WorldWideScience

Sample records for film dosimeter response

  1. Dose response of thin-film dosimeters irradiated with 80-120 keV electrons

    DEFF Research Database (Denmark)

    Helt-Hansen, J.; Miller, A.; Sharpe, P.

    2005-01-01

    Thin-film dosimeters (Riso B3 and alanine films) were irradiated at 10 MeV and 80-120 keV electron accelerators, and it has been shown that the radiation response of the dosimeter materials (the radiation chemical yields) are constant at these irradiation energies. However, dose gradients within...... the dosimeters mean that calibration functions at the lower electron energies will be dependent on both irradiation energy and the required effective point of measurement of the dosimeter. These are general effects that apply to any dosimeters that have non-linear response functions and where dose gradients...

  2. Effects of temperature and humidity during irradiation on the response of a film dosimeter

    Science.gov (United States)

    Khan, Hasan M.; Wahid, Mian S.

    1995-09-01

    A commercially available leuco dye containing polyvinyl butyral based film (FWT-63-02) has been investigated ctrophotometrically for its dosimetric characteristic and for its use as routine dosimeter in radiation processing for the absorbed dose range 0.1 to 10 kGy. The present study was carried out to evaluate the performance of dosimeter under different environmental conditions (i.e. effects of temperature and relative humidity during irradiation). The response was measured at peak wavelength of 600 nm as well as at a number of other wavelengths (550, 625, 640 and 650 nm). The dosimeter was found to show quite stable response up to a radiation chamber temperature of 40°C. The dosimeter also showed stable behavior at low or moderate relative humidity conditions (<76%) in the radiation chamber. The characteristics of the dosimeter are suitable for its possible application in radiation processing, food irradiation and sterilization applications.

  3. Response of radiochromic film dosimeters to gamma rays in different atmospheres

    Science.gov (United States)

    McLaughlin, W. L.; Humphreys, J. C.; Wenxiu, Chen

    The high-dose gamma ray response (10 3 - 5×10 5 Gy) of radiochromic film dosimeters, with ten kinds of plastic matrices (polychlorostyrene containing 1 or 25% C ?, polybromostyrene containing 2 or 43% Br, nylon, polyvinyl chloride, cellulose triacetate, and an aromatic polymide) were investigated when irradiated under certain conditions in vacuum and in different atmospheres (air, oxygen, nitrogen, and nitrous oxide). In addition, the stability of the films was studied for storage periods up to one month after irradiation under these conditions. The responses and stabilities of the polyhalostyrene and nylon films were only slightly affected by the different atmospheres of irradiation, but there were marked differences of response for the other film types. The dyed cellulose triacetate films and polyvinylchloride films are generally more sensitive in N 2O and O 2-deprived atmospheres than in air or in O 2, but the opposite is true for the dyed polyvinyl butyral and aromatic nylon films. The dyed cellulose triacetate and dyed polychlorostryrene with 1% C ? are the most stable films for all conditions or irradiation. For accurate routine radiation processing dosimetry, it is important to know the conditions of irradiation so that appropriate dosimetry systems and procedures may be used and so that suitable correction factors can be applied. Emphasis must be given to differences in atmospheric conditions encountered by dosimeters in practical industrial situations, which may cause marked differences in ultimate response factors.

  4. NONLINEAR RESPONSES OF GAMMA —RAY DOSIMETERS

    Institute of Scientific and Technical Information of China (English)

    罗达玲; 杨健明; 等

    1994-01-01

    Either sublinear or supralinear responses of dosimeters to γ-ray can be described by a response function derived from statistical Poisson distribution.The characteristic parameters of the function determine linearity,sublinearity and supralinearlty in their responses.The experimental data of gamma dose-responses of alanine ESR dosimeters film dosimeters.LiF(Mg,Cu,P) and LiF(Mg,Ti) thermoluminescence dosimeters are used to test the response function.

  5. Spectral response of solvent-cast polyvinyl chloride (PVC) thin film used as a long-term UV dosimeter.

    Science.gov (United States)

    Amar, Abdurazaq; Parisi, Alfio V

    2013-08-01

    The spectral response of solvent-cast polyvinyl chloride (PVC) thin film suitable for use as a long-term UV dosimeter has been determined by measuring the UV induced change in the 1064 cm(-1) peak intensity of the PVC's infrared (IR) spectra as a function of the wavelength of the incident radiation. Measurements using cut-off filters, narrow band-pass filters and monochromatic radiation showed that the 16 μm PVC film responds mainly to the UVB band. The maximum response was at 290 nm and decreasing exponentially with wavelength up to about 340 nm independent of temperature and exposure dose. The most suitable concentration (W/V%) of PVC/Tetrahydrofuran solution was found to be 10% and the best thickness for the dosimeter was determined as 16 μm.

  6. A new radiochromic thin-film dosimeter system

    Science.gov (United States)

    Miller, A.; Batsberg, W.; Karman, W.

    A film dosimeter based on pararosaniline cyanide dissolved in polyvinyl butyral (PVB) has been developed and its properties are described. The dosimeter is made in 3 versions: 1) a clear, thin film that requires a thickness measurement for evaluation, 2) a film with a relatively high absorbance for automatic thickness correction, 3) a UV-protected pressure-sensitive adhesive tape. The response of the dosimeter is independent on the dose rate, and it may be used for routine dose measurement of both gamma and electron irradiation. Its high spatial resolution makes it particularly useful for dose distribution measurements.

  7. A PC based thin film dosimeter system

    DEFF Research Database (Denmark)

    Miller, A.; Hargittai, P.; Kovacs, A.

    2000-01-01

    A dosimeter system based on the Riso B3 dosimeter film, an office scanner for use with PC and the associated software is presented. The scanned image is analyzed either with standard software (Paint Shop Pro 5 or Excel) functions or with the computer code "Scanalizer" that allows presentation...

  8. Energy Response and Physical Reoperties of NTA* Personnel NeutronDosimeter Nuclear Track Film

    Energy Technology Data Exchange (ETDEWEB)

    Lehman, Richard L

    1961-03-13

    This paper reports the chemical and physical properties of the NTA film packet. It correlates with these properties the response of this packet to neutrons of various energies. In this correlation the concept of the track unit is introduced as a basic unit for reporting film-packet response.

  9. Temperature and relative humidity dependence of radiochromic film dosimeter response to gamma electron radiation

    DEFF Research Database (Denmark)

    McLaughlin, W.L.; Puhl, J.M.; Miller, A.

    1995-01-01

    on some earlier studies, their response functions have been reported to be dependent on the temperature and relative humidity during irradiation. The present study investigates differences in response over practical ranges of temperature, relative humidity, dose, and for different recent batches of films...... of both types. It is observed that for each new batch of film to be used for radiation processing, the effects of such parameters on response to both gamma rays and electrons should be investigated. It is also suggested that the films should be packaged under controlled atmospheric conditions (relative...

  10. Radiation-induced color bleaching of methyl red in polyvinyl butyral film dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Al Zahrany, Awad A., E-mail: azahrany@kacst.edu.sa [Atomic Energy Research Institute, King Abdulaziz City for Science and Technology, (KACST), P.O. BOX 6086, Riyadh 11442 (Saudi Arabia); Rabaeh, Khalid A. [Atomic Energy Research Institute, King Abdulaziz City for Science and Technology, (KACST), P.O. BOX 6086, Riyadh 11442 (Saudi Arabia); Radiography Department, Faculty of Allied Health Sciences, Hashemite University, Zarqa (Jordan); Basfar, Ahmed A. [Atomic Energy Research Institute, King Abdulaziz City for Science and Technology, (KACST), P.O. BOX 6086, Riyadh 11442 (Saudi Arabia)

    2011-11-15

    Radio-chromic film based on polyvinyl butyral (PVB) containing different concentrations of methyl red (MR) dye for 0.125, 0.25 and 0.5 mM has been introduced as high dose dosimeter. The dosimeters were irradiated with gamma ray from {sup 60}Co source at doses from 5 to 150 kGy. UV/vis spectrophotometry was used to investigate the optical density of unirradiated and irradiated films in terms of absorbance at 497 nm. The dose sensitivity of MR-PVB film dosimeter increases strongly with increase of absorbed dose as well as increase of concentrations of MR dye. The effects of irradiation temperature, relative humidity, dose rate and the stability of the response of the films after irradiation were investigated and found that these films could be used as routine dosimeter in industrial radiation processing. The useful dose range of developed MR-PVB film dosimeters is in the range of 5-100 kGy. - Highlights: > This manuscript relates to radio-chromic dosimeter for used in high dose radiation processing. > Methyl red MR contains azo group which breaking due to gamma radiation, resulting in color bleaching. > Radio-chromic film PVB containing different concentrations of MR dye has been introduced. > The color bleaching of MR-PVB film dosimeter increases gradually with increasing absorbed dose. > Response of MR-PVB films was slightly affected by irradiation temperature and relative humidity.

  11. Comparison of dosimeter response: ionization chamber, TLD, and Gafchromic EBT2 film in 3D-CRT, IMRT, and SBRT techniques for lung cancer

    Science.gov (United States)

    Fitriandini, A.; Wibowo, W. E.; Pawiro, S. A.

    2016-03-01

    This research was conducted by measuring point dose in the target area (lungs), heart, and spine using four dosimeters (PTW N30013, Exradin A16, TLD, and the Gafchromic EBT2 film). The measurement was performed in CIRS 002LFC thorax phantom. The main objective of this study was to compare the dosimetry of those different systems. Dose measurements performed only in a single fraction of irradiation. The measurements result shown that TLD has the least accuracy and precision. As the effect of volume averaging, ionization chamber reaches the discrepancy value up to -13.30% in the target area. EBT2 film has discrepancy value of <1% in the 3D-CRT and IMRT techniques. This dosimeter is proposed to be an appropriate alternative dosimeter to be used at point dose verification.

  12. Radiation-induced color bleaching of methyl red in polyvinyl butyral film dosimeter

    Science.gov (United States)

    Al Zahrany, Awad A.; Rabaeh, Khalid A.; Basfar, Ahmed A.

    2011-11-01

    Radio-chromic film based on polyvinyl butyral (PVB) containing different concentrations of methyl red (MR) dye for 0.125, 0.25 and 0.5 mM has been introduced as high dose dosimeter. The dosimeters were irradiated with gamma ray from 60Co source at doses from 5 to 150 kGy. UV/vis spectrophotometry was used to investigate the optical density of unirradiated and irradiated films in terms of absorbance at 497 nm. The dose sensitivity of MR-PVB film dosimeter increases strongly with increase of absorbed dose as well as increase of concentrations of MR dye. The effects of irradiation temperature, relative humidity, dose rate and the stability of the response of the films after irradiation were investigated and found that these films could be used as routine dosimeter in industrial radiation processing. The useful dose range of developed MR-PVB film dosimeters is in the range of 5-100 kGy.

  13. Photographic film as a pocket radiation dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Pardue, L.A.; Goldstein, N.; Wollan, E.O.

    1944-04-25

    The energy dependence of film blackening is discussed and shown graphically. The exposure range of films is discussed, and blackening is plotted vs exposure for DuPont No. 502, and for the less sensitive DuPont No. 351. A plan is then described for monitoring radiation exposure to workers by requiring the worker to carry an x-ray film of dental packet size in a badge designed for the purpose. (LEW)

  14. Automatic scanning of NTA film neutron dosimeters

    CERN Document Server

    Müller, R

    1999-01-01

    At the European Laboratory for Particle Physics CERN, personal neutron monitoring for over 4000 collaborators is performed with Kodak NTA film, one of the few suitable dosemeters in the stray radiation environment of a high energy accelerator. After development, films are scanned with a projection microscope. To overcome this lengthy and strenuous procedure an automated analysis system for the dosemeters has been developed. General purpose image recognition software, tailored to the specific needs with a macro language, analyses the digitised microscope image. This paper reports on the successful automatic scanning of NTA films irradiated with neutrons from a /sup 238/Pu-Be source (E approximately=4 MeV), as well as on the extension of the method to neutrons of higher energies. The question of detection limits is discussed in the light of an application of the method in routine personal neutron monitoring. (9 refs).

  15. An automatic evaluation system for NTA film neutron dosimeters

    CERN Document Server

    Müller, R

    1999-01-01

    At CERN, neutron personal monitoring for over 4000 collaborators is performed with Kodak NTA films, which have been shown to be the most suitable neutron dosimeter in the radiation environment around high-energy accelerators. To overcome the lengthy and strenuous manual scanning process with an optical microscope, an automatic analysis system has been developed. We report on the successful automatic scanning of NTA films irradiated with sup 2 sup 3 sup 8 Pu-Be source neutrons, which results in densely ionised recoil tracks, as well as on the extension of the method to higher energy neutrons causing sparse and fragmentary tracks. The application of the method in routine personal monitoring is discussed. $9 overcome the lengthy and strenuous manual scanning process with an optical microscope, an automatic analysis system has been developed. We report on the successful automatic scanning of NTA films irradiated with /sup 238/Pu-Be source $9 discussed. (10 refs).

  16. Mercuric iodide dosimeter response to high energy electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Loewinger, E.; Nissenbaum, J.; Schieber, M.M.

    1988-01-01

    Mercuric iodide solid state dosimeter response to high energy electron beams of up to 35 MeV is reported. High sensitivity of up to 1.5 V/cGy was observed with a 200 V external bias, as well as several mV/cGy, with no external bias for small volume (approx. 10 mm/sup 3/) detectors. The physical characteristics of the detector response are discussed, showing the feasibility of mercuric iodide as a reliable dosimeter for high energy electron beams.

  17. Miniature personal electronic UVR dosimeter with erythema response and time-stamped readings in a wristwatch.

    Science.gov (United States)

    Heydenreich, Jakob; Wulf, Hans Christian

    2005-01-01

    Personal ultraviolet radiation (UVR) dosimetry is important because sunlight is the most important risk factor for skin cancer and a risk factor for some eye diseases and immunosuppression and related disorders. Integrating devices, such as polysulphone film dosimeters, are generally used. To measure the exact dose at specific times, we have developed a personal electronic UVR dosimeter that makes time-stamped measurements. It has a sensor with an erythema action spectrum response and a linear sensitivity (dose-response) with no offset. The sensor has cosine response, and the dosimeter can cope with environmental conditions such as rain, temperature and dirt. It can be programmed to measure with different time intervals and save the average of a specified number of measurements in the memory that can store 32 000 time-stamped measurements. It is small (36 x 28 x 13 mm), weighs 14 g and can work for 4 months without maintenance. It is worn on the wrist, is equipped with a watch showing the time and may thus be used in large-scale studies. The sensitivity can change by 10% due to temperature changes from -5 to 40 degrees C. The UVR dosimeter sensitivity is 0.09 standard erythema doses (SED)/h and the difference in total received dose during 7 days between a Solar Light 501 UV-Biometer (186 SED) and our UVR dosimeter was 3% and the median difference in daily total dose was 2.2%. The dosimeter provides unique possibilities. Examples of personal UVR measurements, data calculations and how they can be interpreted are given.

  18. Response of ionization chamber based pocket dosimeter to beta radiation.

    Science.gov (United States)

    Kumar, Munish; Gupta, Anil; Pradhan, S M; Bakshi, A K; Chougaonkar, M P; Babu, D A R

    2013-12-01

    Quantitative estimate of the response of ionization chamber based pocket dosimeters (DRDs) to various beta sources was performed. It has been established that the ionization chamber based pocket dosimeters do not respond to beta particles having energy (Emax)1 MeV, the DRDs exhibit measureable response and the values are ~8%, ~14% and ~27% per mSv for natural uranium, (90)Sr/(90)Y and (106)Ru/(106)Rh beta sources respectively. As the energy of the beta particles increases, the response also increases. The response of DRDs to beta particles having energy>1 MeV arises due to the fact that the thickness of the chamber walls is less than the maximum range of beta particles. This may also be one of the reasons for disparity between doses measured with passive/legal dosimeters (TLDs) and DRDs in those situations in which radiation workers are exposed to mixed field of gamma photons and beta particles especially at uranium processing plants, nuclear (power and research) reactors, waste management facilities and fuel reprocessing plants etc. The paper provides the reason (technical) for disparity between the doses recorded by TLDs and DRDs in mixed field of photons and beta particles.

  19. The Response of Alanine Dosimeters in Thermal Neutron Fields

    DEFF Research Database (Denmark)

    Schmitz, T.; Bassler, Niels; Sharpe, P.

    Purpose: Boron Neutron Capture Therapy (BNCT) is a special kind of particle therapy, based on the neutron induced fission of the boron isotope 10B [1]. We have performed dosimetry experiments on the mixed neutron and gamma fields at the TRIGA Mark II research reactor in Mainz. Commonly, dosimetry...... in such fields is realized by foil activation and ion chambers [2]. Here we investigate alanine as an easier and more robust alternative dosimeter. Methods: We have performed four phantom experiments at the TRIGA Mark II research reactor in Mainz [3], in a predominantly thermal neutron field with a strong gamma...... neutron capture of hydrogen. The primary gamma dose deposited originate from the reactor core itself. Conclusion: Alanine dosimeters are suitable of measurements in mixed neutron fields and the alanine response in thermal neutron fields can be fully understood by the used interpretation model. In further...

  20. Film dosimeters based on methylene blue and methyl orange in polyvinyl alcohol

    DEFF Research Database (Denmark)

    Chung, W.H.; Miller, A.

    1994-01-01

    Polyvinyl alcohol (PVA) films containing methylene blue and methyl orange are useful as gamma and electron radiation dosimeters. Absorbed doses should not exceed 40 kGy for methylene blue and 500 kGy for methyl orange. Because PVA is water-soluble, the films may be made without toxic solvents. Th...

  1. Polyvinyl butyral films containing leuco-malachite green as low-dose dosimeters

    Science.gov (United States)

    Mai, Hoang Hoa; Solomon, H. M.; Taguchi, M.; Kojima, T.

    2008-04-01

    Thin films containing leuco-malachite green (LMG) dye in polyvinyl butyral (PVB) have been developed for dose measurements of a few hundreds Gy level. The film shows significant color change in the visible range, and the sensitivity of the film to absorbed dose was enhanced by addition of chloride-containing compounds, such as chloral hydrate or 2,2,2-trichloroethanol. The film is suitable as dosimeters for dose measurements, e.g. in food irradiation and environmental protection.

  2. Polyvinyl butyral films containing leuco-malachite green as low-dose dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Hoang Hoa Mai [Institute for Nuclear Science Technique, Vietnam Atomic Energy Commission (VAEC), 59 Ly Thuong Kiet, Hanoi (Viet Nam); Solomon, H.M. [Philippine Nuclear Research Institute (PNRI), Commonwealth Avenue, Diliman Quezon City (Philippines); Taguchi, M. [Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), 1233 Watanuki-machi, Takasaki-shi. Gunma 370-1292 (Japan); Kojima, T. [Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), 1233 Watanuki-machi, Takasaki-shi. Gunma 370-1292 (Japan)], E-mail: kojima.takuji@jaea.go.jp

    2008-04-15

    Thin films containing leuco-malachite green (LMG) dye in polyvinyl butyral (PVB) have been developed for dose measurements of a few hundreds Gy level. The film shows significant color change in the visible range, and the sensitivity of the film to absorbed dose was enhanced by addition of chloride-containing compounds, such as chloral hydrate or 2,2,2-trichloroethanol. The film is suitable as dosimeters for dose measurements, e.g. in food irradiation and environmental protection.

  3. Thin plastic radiochromic dye films as ionizing radiation dosimeters

    Science.gov (United States)

    Buenfil-Burgos, A. E.; Uribe, R. M.; de la Piedad, A.; McLaughlin, W. L.; Miller, A.

    Radiochromic dye films were fabricated by casting polyvinyl butyral (PVB) in weakly acidic solution with the leucocyanide of pararosaniline. Calibrated films of 10-25 μm thickness were useful over a response range of about 10 3-10 5 Gy, by applying spectrophotometric analysis at the wavelength of the maximum of the radiation-induced absorption band (550 nm). The effects of temperature, pressure, and humidity during curing of the films pointed to the need for carefully controlling these parameters. For casting films at the high altitude of Mexico City (≈ 2500 meters), the optimum conditions are 45-75% r.h. and 20-25° C for a drying period of 72 to 92 hours, when the solvent is a mixture of ethanol and 2-methoxyethanol. The response of films fabricated in this way were compared with those of commercially available PVB and Nylon films. The effects of temperature, humidity, and period of storage on the response of these films were studied in the range from -5 to 60° C and from 11.8 to 96.6% r.h. for up to four months between irradiation and spectral analysis, and within nominal experimental uncertainty (≈ 10%), we found that all the radiochromic films studied can be stored for extended periods under steady-state conditions in the temperature range from -5 to 30° C and from 11.8-75.6% r.h. without correction factors for instability, but under extreme conditions of moisture at elevated temperatures the radiochromic image showed a fading effect on storage.

  4. Comprehensive Angular Response Study of LLNL Panasonic Dosimeter Configurations and Artificial Intelligence Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Stone, D. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-06-30

    In April of 2016, the Lawrence Livermore National Laboratory External Dosimetry Program underwent a Department of Energy Laboratory Accreditation Program (DOELAP) on-site assessment. The assessment reported a concern that the study performed in 2013 Angular Dependence Study Panasonic UD-802 and UD-810 Dosimeters LLNL Artificial Intelligence Algorithm was incomplete. Only the responses at ±60° and 0° were evaluated and independent data from dosimeters was not used to evaluate the algorithm. Additionally, other configurations of LLNL dosimeters were not considered in this study. This includes nuclear accident dosimeters (NAD) which are placed in the wells surrounding the TLD in the dosimeter holder.

  5. Calibration of thin-film dosimeters irradiated with 80-120 kev electrons

    DEFF Research Database (Denmark)

    Helt-Hansen, J.; Miller, A.; McEwen, M.

    2004-01-01

    A method for calibration of thin-film dosimeters irradiated with 80-120keV electrons has been developed. The method is based on measurement of dose with a totally absorbing graphite calorimeter, and conversion of dose in the graphite calorimeter to dose in the film dosimeter by Monte Carlo...... calculations. A thermal model was developed to estimate the temperature contributions from the air above the calorimeter that is heated by the electron beam. As an example, Riso B3 thin-film dosimeters were calibrated by 80-120 keV electron irradiation and compared with a calibration carried out at 10 Me......V electron irradiation. The two calibrations were found to be equal within the estimated uncertainties of +/-10% at 1 s.d. (C) 2004 Elsevier Ltd. All rights reserved....

  6. Enhancement of Dose Response and Nuclear Magnetic Resonance Image of PAGAT Polymer Gel Dosimeter by Adding Silver Nanoparticles

    Science.gov (United States)

    Sabbaghizadeh, Rahim; Shamsudin, Roslinda; Deyhimihaghighi, Najmeh; Sedghi, Arman

    2017-01-01

    In the present study, the normoxic polyacrylamide gelatin and tetrakis hydroxy methyl phosphoniun chloride (PAGAT) polymer gel dosimeters were synthesized with and without the presence of silver (Ag) nanoparticles. The amount of Ag nanoparticles varied from 1 to 3 ml with concentration 3.14 g/l, thus forming two types of PAGAT polymer gel dosimeters before irradiating them with 6 to 25 Gy produced by 1.25-MeV 60Co gamma rays. In this range, the predominant gamma ray interaction with matter is by Compton scattering effect, as the photoelectric absorption effect diminishes. MRI was employed when evaluating the polymerization of the dosimeters and the gray scale of the MRI film was determined via an optical densitometer. Subsequent analyses of optical densities revealed that the extent of polymerization increased with the increase in the absorbed dose, while the increase of penetration depth within the dosimeters has a reverse effect. Moreover, a significant increase in the optical density-dose response (11.82%) was noted for dosimeters containing 2 ml Ag nanoparticles. PMID:28060829

  7. Evaluation of the effect of temperature variation on response of PRESAGE® dosimeter

    Directory of Open Access Journals (Sweden)

    Bagher Farhood

    2017-01-01

    Conclusion: The finding showed that temperature changes have not impact on the absorption peak. In addition, the results related to the effect of temperature variation on the response of PRESAGE ® dosimeter showed that in the range of clinical applications (temperatures below 75°C, temperature variation has no effect on PRESAGE ® dosimeter response.

  8. OSL and TL dosimeter characterization of boron doped CVD diamond films

    Science.gov (United States)

    Gonçalves, J. A. N.; Sandonato, G. M.; Meléndrez, R.; Chernov, V.; Pedroza-Montero, M.; De la Rosa, E.; Rodríguez, R. A.; Salas, P.; Barboza-Flores, M.

    2005-04-01

    Natural diamond is an exceptional prospect for clinical radiation dosimetry due to its tissue-equivalence properties and being chemically inert. The use of diamond in radiation dosimetry has been halted by the high market price; although recently the capability of growing high quality CVD diamond has renewed the interest in using diamond films as radiation dosimeters. In the present work we have characterized the dosimetric properties of diamond films synthesized by the HFCVD method. The thermoluminescence and the optically stimulated luminescence of beta exposed diamond sample containing a B/C 4000 ppm doping presents excellent properties suitable for dosimetric applications with β-ray doses up to 3.0 kGy. The observed OSL and TL performance is reasonable appropriate to justify further investigation of diamond films as dosimeters for ionizing radiation, specially in the radiotherapy field where very well localized and in vivo and real time radiation dose applications are essential.

  9. The responses of three kinds of passive dosimeters to secondary cosmic rays in the lower atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhen; Chen, Bo, E-mail: bochenfys@fudan.edu.cn; Zhuo, Weihai; Fan, Dunhuang; Zhang, Yu [Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032 (China); Zhao, Chao [Shanghai Institute of Measurement and Testing Technology, 1500 Zhangheng Road, Shanghai 201203 (China)

    2015-12-15

    For accurate measurements of the secondary cosmic rays by using passive dosimeters, the relative responses of the thermoluminescence dosimeter (TLD), optically stimulated luminescence (OSL) dosimeter, and radiophotoluminescent glass dosimeter (RPLGD) were studied. The cosmic-ray shower generator was used to simulate the secondary cosmic rays at the sea level. Monte Carlo simulations were performed to calculate the air kerma and absorbed doses in each kind of dosimeter. The results showed that compared with their responses to gamma rays of {sup 137}Cs, the relative responses of the TLD, OSL, and RPLGD were 0.786, 0.707, and 0.735 to the hard component of cosmic rays, respectively, and the values were 0.904, 0.838, and 0.857 to the soft component of cosmic rays, respectively. To verify the simulations results, an in situ measurement with the three kinds of dosimeters was performed at the same place. The results indicated that the secondary cosmic rays monitored with the three kinds of dosimeters were well consistent with each other provided their relative responses were taken into account.

  10. Study of Fricke gel dosimeter response for different gel quality

    Science.gov (United States)

    Cavinato, C. C.; Campos, L. L.

    2010-11-01

    The Fricke xylenol gel (FXG) dosimeter has been studied for application in radiotherapy because it is capable of to measure the spatial distribution of radiation doses. The dosimetry is based on the oxidation of ferrous (Fe2+) to ferric (Fe3+) ions radiation induced, related to the radiation dose. The gel material usually employed is the 300 Bloom gelatin, which is imported and very expensive in Brazil. Aiming to analyze the viability of to use a locally produced and low cost gel material, in this work the spectrophotometric responses of FXG solutions prepared using 270 Bloom gelatin commercially available and 300 Bloom gelatin imported were compared. The absorption spectra of solutions prepared with 5% by weight 270 and 300 Bloom gelatins non-irradiated and irradiated with 60Co gamma radiation in the dose range between 0.5 and 100 Gy were analysed, the dose-response curves were evaluated and the useful dose range was established. The obtained results indicate that the FXG solution prepared with 270 Bloom gelatin presents good performance, similar to that presented by the FXG solution prepared with 300 Bloom gelatin and its use can be recommended owing to the low cost and the availability in local market.

  11. FXG dosimeter response for three-dimensional conformal radiotherapy using different evaluation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Cavinato, Christianne C.; Campos, Leticia L., E-mail: ccavinato@ipen.b, E-mail: lcrodri@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Souza, Benedito H.; Carrete Junior, Henrique; Daros, Kellen A.C.; Medeiros, Regina B., E-mail: bhsouza@unifesp.b, E-mail: daros.kellen@unifesp.b, E-mail: rbitel-li.ddi@epm.b [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Dept. de Diagnostico por Imagem; Giordani, Adelmo J. [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Servico de Radioterapia

    2011-07-01

    This work aims to compare the dose-response of the Fricke xylenol gel (FXG) dosimeter developed at IPEN using 270 Bloom gelatin from porcine skin made in Brazil evaluated using the magnetic resonance imaging (MRI) technique with the dosimetric response evaluated using the optical absorption (OA) spectrophotometry technique, in order to verify the possibility of quality assurance (QA) and reproducibility of FXG dosimeter to be carried out routinely using the OA technique for three-dimensional conformal radiotherapy (3DCRT) application using a 6 MV photons linear accelerator. The response in function of the absorbed dose of FXG dosimeter developed at IPEN presents linear behavior in clinical interest dose range when irradiated with Co-60 gamma radiation and 6 MV photons and evaluated using the MRI and OA techniques. The results indicate that the optical technique can be used for QA of FXG dosemeter when used in the possible application in QA of 3DCRT. (author)

  12. On the response of electronic personal dosimeters in constant potential and pulsed X-ray beams

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Margarete C.; Silva, Teogenes; Silva, Claudete R.E., E-mail: margaretecristinag@gmail.com [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Oliveira, Paulo Marcio C. de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Anatomia e Imagem

    2015-07-01

    Electronic personal dosimeters (EPDs) based on solid state detectors have widely been used but some deficiencies in their response in pulsed radiation beams have been reported. Nowadays, there is not an international standard for pulsed X-ray beams for calibration or type testing of dosimeters. Irradiation conditions for testing the response of EPDs in both the constant potential and pulsed X-ray beams were established in CDTN. Three different types of EPDs were tested in different conditions in similar ISO and IEC X-ray qualities. Results stressed the need of performing additional checks before using EPDs in constant potential or pulsed X-rays. (author)

  13. On the response of electronic personal dosimeters in constant potential and pulsed x- ray beams

    Science.gov (United States)

    Guimarães, M. C.; Silva, C. R. E.; Oliveira, P. M. C.; da Silva, T. A.

    2016-07-01

    Electronic personal dosimeters (EPDs) based on solid state detectors have widely been used but some deficiencies in their response in pulsed radiation beams have been reported. Nowadays, there is not an international standard for pulsed x-ray beams for calibration or type testing of dosimeters. Irradiation conditions for testing the response of EPDs in both the constant potential and pulsed x-ray beams were established in CDTN. Three different types of EPDs were tested in different conditions in similar ISO and IEC x-ray qualities. Results stressed the need of performing additional checks before using EPDs in constant potential or pulsed x-rays.

  14. Dependence of alanine gel dosimeter response as a function of photon clinical beams dose rate

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cleber Feijo, E-mail: cleber.feijo@famesp.com.br [Faculdade Metodo de Sao Paulo (FAMESP), SP (Brazil); Campos, Leticia Lucente, E-mail: Icrodri@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-11-01

    Gel dosimetry is a new area developed by Gore, it is ery useful for application in radiotherapy because using NMR imaging as evaluation technique is possible to evaluate three dimensional absorbed dose distribution. The measure technique is based on difference of ferrous (Fe{sup 2+}) and ferric (Fe{sup 3+}) ) ions concentration that can be measured also by spectrophotometry technique. The Alanine gel dosimeter was developed at IPEN. The alanine is an amino acid and tissue equivalent material that presents significant improvement on previous alanine dosimetry systems. The addition of Alanine increases the production of ferric ions in the solution. This work aims to study the dose rate dependence of photon clinical beams radiation on the alanine gel dosimeter optical response, as well as the response repeatability and gel production reproducibility, since this property is very important for characterization and standardization of any dosimeter. (author)

  15. Temperature response of a number of plastic dosimeters for radiation processing

    Science.gov (United States)

    Sohrabpour, M.; Kazemi, A. A.; Mousavi, H.; Solati, K.

    1993-10-01

    Various plastic dosemeters are employed for dosimetry control of radiation processing within gamma and electron irradiation facilities. The temperature response of a dosimeter is important when the dose to such a dosimeter is accumulated under varying irradiation temperatures. Such measurements would be significant for proper assessment of the dose for better process control, as well as, performance evaluation of dosimetry systems. In this work we have developed a high current peltier junction temperature controller system for our Gammacell-220. This system has been designed to regulate the operating temperature of the irradiation chamber in the range of 0 to 80 C this system has been applied to measure the temperature response of the red perspex, a local clear PMMA, Gammex, Gammachrome, and Gafchromic dosimeters. The curves of relative performance or variation of the induced optical densities of the above dosemeters versus the irradiation temperature at fixed dose values are obtained.

  16. Development and evaluation of polycrystalline cadmium telluride dosimeters for accurate quality assurance in radiation therapy

    Science.gov (United States)

    Oh, K.; Han, M.; Kim, K.; Heo, Y.; Moon, C.; Park, S.; Nam, S.

    2016-02-01

    For quality assurance in radiation therapy, several types of dosimeters are used such as ionization chambers, radiographic films, thermo-luminescent dosimeter (TLD), and semiconductor dosimeters. Among them, semiconductor dosimeters are particularly useful for in vivo dosimeters or high dose gradient area such as the penumbra region because they are more sensitive and smaller in size compared to typical dosimeters. In this study, we developed and evaluated Cadmium Telluride (CdTe) dosimeters, one of the most promising semiconductor dosimeters due to their high quantum efficiency and charge collection efficiency. Such CdTe dosimeters include single crystal form and polycrystalline form depending upon the fabrication process. Both types of CdTe dosimeters are commercially available, but only the polycrystalline form is suitable for radiation dosimeters, since it is less affected by volumetric effect and energy dependence. To develop and evaluate polycrystalline CdTe dosimeters, polycrystalline CdTe films were prepared by thermal evaporation. After that, CdTeO3 layer, thin oxide layer, was deposited on top of the CdTe film by RF sputtering to improve charge carrier transport properties and to reduce leakage current. Also, the CdTeO3 layer which acts as a passivation layer help the dosimeter to reduce their sensitivity changes with repeated use due to radiation damage. Finally, the top and bottom electrodes, In/Ti and Pt, were used to have Schottky contact. Subsequently, the electrical properties under high energy photon beams from linear accelerator (LINAC), such as response coincidence, dose linearity, dose rate dependence, reproducibility, and percentage depth dose, were measured to evaluate polycrystalline CdTe dosimeters. In addition, we compared the experimental data of the dosimeter fabricated in this study with those of the silicon diode dosimeter and Thimble ionization chamber which widely used in routine dosimetry system and dose measurements for radiation

  17. Characteristics of a novel polymer gel dosimeter formula for MRI scanning: Dosimetry, toxicity and temporal stability of response.

    Science.gov (United States)

    Abtahi, S M

    2016-09-01

    The present study intended to investigate the composition of a new polymer gel dosimeter. The new composition would be more suitable for a wide range of applications in comparison to polyacrylamide gel dosimeter since its extremely toxic acrylamide has been replaced with less harmful monomer i.e. 2-Acrylamido-2-MethylPropane Sulfonic acid (AMPS). To this end, the PAGAT gel dosimeter formula was used as a basis to test the new formulation of polymer gel dosimeter with a different monomer (AMPS) instead of acrylamide by using the %6T and %50C to the formula. The new formulation was named PAMPSGAT (Poly AMPS, Gelatin and THPC) polymer gel dosimeter. Moreover, the MRI response (R2) of dosimeters was analyzed in terms of different dose range as well as post-irradiation time. The results indicated that the dose-response (R2) of AMPS/Bis had a linear trend over a wide dose range. Furthermore, the results showed an acceptable temporal stability for the new polymer gel dosimeter.

  18. New Neutron Dosimeter

    CERN Multimedia

    2001-01-01

    CERN has been operating an Individual Dosimetry Service for neutrons for about 35 years. The service was based on nuclear emulsions in the form of film packages which were developed and scanned in the Service. In 1999, the supplier of theses packages informed CERN that they will discontinue production of this material. TIS-RP decided to look for an external service provider for individual neutron dosimetry. After an extensive market survey and an invitation for tender, a supplier that met the stringent technical requirements set up by CERN's host states for personal dosimeters was identified. The new dosimeter is based on a track-etching technique. Neutrons have the capability of damaging plastic material. The microscopic damage centres are revealed by etching them in a strong acid. The resulting etch pits can be automatically counted and their density is proportional to dose equivalent from neutrons. On the technical side, the new dosimeter provides an improved independence of its response from energy and th...

  19. Dosimetry for small fields in stereotactic radiosurgery using gafchromic MD-V2-55 film, TLD-100 and alanine dosimeters.

    Directory of Open Access Journals (Sweden)

    Guerda Massillon-J L

    Full Text Available This work investigated the suitability of passive dosimeters for reference dosimetry in small fields with acceptable accuracy. Absorbed dose to water rate was determined in nine small radiation fields with diameters between 4 and 35 mm in a Leksell Gamma Knife (LGK and a modified linear accelerator (linac for stereotactic radiosurgery treatments. Measurements were made using Gafchromic film (MD-V2-55, alanine and thermoluminescent (TLD-100 dosimeters and compared with conventional dosimetry systems. Detectors were calibrated in terms of absorbed dose to water in (60Co gamma-ray and 6 MV x-ray reference (10×10 cm(2 fields using an ionization chamber calibrated at a standards laboratory. Absorbed dose to water rate computed with MD-V2-55 was higher than that obtained with the others dosimeters, possibly due to a smaller volume averaging effect. Ratio between the dose-rates determined with each dosimeter and those obtained with the film was evaluated for both treatment modalities. For the LGK, the ratio decreased as the dosimeter size increased and remained constant for collimator diameters larger than 8 mm. The same behaviour was observed for the linac and the ratio increased with field size, independent of the dosimeter used. These behaviours could be explained as an averaging volume effect due to dose gradient and lack of electronic equilibrium. Evaluation of the output factors for the LGK collimators indicated that, even when agreement was observed between Monte Carlo simulation and measurements with different dosimeters, this does not warrant that the absorbed dose to water rate in the field was properly known and thus, investigation of the reference dosimetry should be an important issue. These results indicated that alanine dosimeter provides a high degree of accuracy but cannot be used in fields smaller than 20 mm diameter. Gafchromic film can be considered as a suitable methodology for reference dosimetry. TLD dosimeters are not

  20. Hanford personnel dosimeter supporting studies FY-1981

    Energy Technology Data Exchange (ETDEWEB)

    1982-08-01

    This report examined specific functional components of the routine external personnel dosimeter program at Hanford. Components studied included: dosimeter readout; dosimeter calibration; dosimeter field response; dose calibration algorithm; dosimeter design; and TLD chip acceptance procedures. Additional information is also presented regarding the dosimeter response to light- and medium-filtered x-rays, high energy photons and neutrons. This study was conducted to clarify certain data obtained during the FY-1980 studies.

  1. Relative response of the alanine dosimeter to medium energy x-rays.

    Science.gov (United States)

    Anton, M; Büermann, L

    2015-08-01

    The response of the alanine dosimeter to kilovoltage x-rays with respect to the dose to water was measured, relative to the response to Co-60 radiation.Two series of x-ray qualities were investigated, one ranging from 30 kV to 100 kV tube voltage (TW series), the other one ranging from 70 kV to 280 kV (TH series). Due to the use of the water calorimeter as a primary standard, the uncertainty of the delivered dose is significantly lower than for other published data. The alanine response was measured as described in a previous publication (Anton et al 2013 Phys. Med. Biol. 58 3259-82). The uncertainty component due to the alanine measurement and analysis is ⩽0.4%, the major part of the combined uncertainty of the relative response originates from the uncertainty of the delivered dose. The relative uncertainties of the relative response vary from ⩽2% for the TW series to ⩽1.1% for the TH series.Different from the behaviour of the alanine dosimeter for megavoltage x-rays or electrons, the relative response drops significantly from unity for Co-60 radiation to less than 64% for the TW quality with a tube voltage of 30 kV. In order to reproduce this behaviour through Monte Carlo simulations, not only the ratio of the absorbed dose to alanine to the absorbed dose to water has to be known, but also the intrinsic efficiency, i.e. the dependence of the number of free radicals generated per unit of absorbed dose on the photon energy. This quantity is not yet accessible for the TW series.For a possible use of the alanine dosimeter for kilovoltage x-rays, for example in electronic brachytherapy, users should rely on the measured data for the relative response which have become available with this publication.

  2. Production dosimeter LiF: Mg, Ti and comparison its responses with dosimeter LiF: Mg, Ti (TLD-100 in Harshaw company against of gamma rays

    Directory of Open Access Journals (Sweden)

    KH Mohammadi

    2010-03-01

    Full Text Available Thermoluminescence dosimeters are small tablets used with 3. 2*3. 2*0. 9mm^3 for measurement of received dose from radioactive various beams. The most common dosimeter is TLD-100 which is lithium-fluoride family and this dosimeter contain magnesium impurities. In this study, first lithium-flouride powder was mixed with titanium and controlled atmosphere samples were heated. After measuring of samples density and hardness, their glow curves were drawn and microscopic pictures of producted samples were provided. Of course, the reader should know that the best press pressure, the best range of temperature heating and the best range of samples heating were determined in 6-8 (ton/cm2, 775-800 ° C and 15-20 h, respectively [1]. Then, the response of producted TLD-100 under radiation of gamma sources, 60Co, was measured in 500 mSv rate and obtained values were compared with obtained values by Harshaw producted samples. Dosimetry characteristics of producted samples was evaluated according to ASTM E 668-00, IEC-ISO 1066 standards. The results of comparisions indicate good agreements between producted sample and Harshaw sample.

  3. Synthesis of aluminum nitride thin films and their potential applications in solid state thermoluminescence dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Choudhary, R.K., E-mail: rupeshkr@barc.gov.in [Materials Processing Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Soni, A. [Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Mishra, P. [Materials Processing Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Mishra, D.R.; Kulkarni, M.S. [Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2014-11-15

    In this work, aluminum nitride thin films were deposited on Si (1 1 1) substrate by magnetron sputtering. The obtained film was studied for thermoluminescence after irradiating it to various doses of γ-rays. Thermoluminescence measurement showed photon emission at an irradiation dose of 100 Gy or higher. Deconvolution of the experimental glow curve indicated that recombination centers in AlN were present below 2 eV trap depth. Irradiated AlN films showed less than 2% fading of TL signals on storage for 1 month in dark conditions and for the same period, light induced fading was also less than 4%. A linear variation of integrated thermoluminescence counts with absorbed dose has been observed up to an irradiation dose of 10 kGy. The deposited film was also characterized by grazing incidence X-ray diffraction, atomic force microscopy and secondary ion mass spectroscopy. Grazing incidence X-ray diffraction measurement of the obtained film has shown formation of polycrystalline wurtzite AlN having preferred orientation along (1 0 0) plane. Secondary ion mass spectroscopy analysis revealed the presence of oxygen in the film. - Highlights: • TL emission in sputter deposited AlN thin films when irradiated to gamma rays. • Linear dose–response up to 10 kGy irradiation dose. • Negligible fading of TL signals on storage. • Nominal light induced TL fading. • AlN thin films found potentially suitable for high dose dosimetry applications.

  4. Comparative dose evaluations between XVI and OBI cone beam CT systems using Gafchromic XRQA2 film and nanoDot optical stimulated luminescence dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Giaddui, Tawfik; Cui Yunfeng; Galvin, James; Yu Yan; Xiao Ying [Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 (United States)

    2013-06-15

    Purpose: To investigate the effect of energy (kVp) and filters (no filter, half Bowtie, and full Bowtie) on the dose response curves of the Gafchromic XRQA2 film and nanoDot optical stimulated luminescence dosimeters (OSLDs) in CBCT dose fields. To measure surface and internal doses received during x-ray volume imager (XVI) (Version R4.5) and on board imager (OBI) (Version 1.5) CBCT imaging protocols using these two types of dosimeters. Methods: Gafchromic XRQA2 film and nanoDot OSLD dose response curves were generated at different kV imaging settings used by XVI (software version R4.5) and OBI (software version 1.5) CBCT systems. The settings for the XVI system were: 100 kVp/F0 (no filter), 120 kVp/F0, and 120 kVp/F1 (Bowtie filter), and for the OBI system were: 100 kVp/full fan, 125 kVp/full fan, and 125 kVp/half fan. XRQA2 film was calibrated in air to air kerma levels between 0 and 11 cGy and scanned using reflection scanning mode with the Epson Expression 10000 XL flat-bed document scanner. NanoDot OSLDs were calibrated on phantom to surface dose levels between 0 and 14 cGy and read using the inLight{sup TM} MicroStar reader. Both dosimeters were used to measure in field surface and internal doses in a male Alderson Rando Phantom. Results: Dose response curves of XRQA2 film and nanoDot OSLDs at different XVI and OBI CBCT settings were reported. For XVI system, the surface dose ranged between 0.02 cGy in head region during fast head and neck scan and 4.99 cGy in the chest region during symmetry scan. On the other hand, the internal dose ranged between 0.02 cGy in the head region during fast head and neck scan and 3.17 cGy in the chest region during chest M20 scan. The average (internal and external) dose ranged between 0.05 cGy in the head region during fast head and neck scan and 2.41 cGy in the chest region during chest M20 scan. For OBI system, the surface dose ranged between 0.19 cGy in head region during head scan and 4.55 cGy in the pelvis region during

  5. Characterization of a medical X-ray machine for testing the response of electronic dosimeters in pulsed radiation fields

    Science.gov (United States)

    Guimarães, Margarete C.; Da Silva, Teógenes A.

    2014-11-01

    Electronic personal dosimeters (EPD) based on solid state detectors have been used for personnel monitoring for radiation protection purpose; their use has been extended to practices with pulsed radiation beams although their performance is not well known. Deficiencies in the EPD response in pulsed radiation fields have been reported; they were not detected before since type tests and calibrations of EPDs were established in terms of continuous X and gamma reference radiations. An ISO working group was formed to elaborate a standard for test conditions and performance requirements of EPDs in pulsed beams; the PTB/Germany implemented a special X-ray facility for generating the reference pulsed radiation beams. In this work, an 800 Plus VMI medical X-ray machine of the Dosimeter Calibration Laboratory of CDTN/CNEN was characterized to verify its feasibility to perform EPD tests. Characterization of the x-ray beam was done in terms of practical peak voltage, half-value layer, mean energy and air kerma rate. Reference dosimeters used for air kerma measurements were verified as far their metrological coherence and a procedure for testing EDPs was established. Electronic personal dosimeters (EPD) have been used for personnel monitoring. EPD use has been extended to pulsed radiation beams. Deficiencies in the EPD response in pulsed beams have been reported. The feasibility of using a medical X-ray machine to perform EPD tests was studied. Reference dosimeters were verified and EPD testing procedure was established.

  6. Response of biological uv dosimeters to the simulated extraterrestrial uv radiation

    Science.gov (United States)

    Bérces, A.; Rontó, G.; Kerékgyártó, T.; Kovács, G.; Lammer, H.

    In the Laboratory polycrystalline uracil thin layer and bacteriophage T7 detectors have been developed for UV dosimetry on the EarthSs surface. Exponential response of the uracil polycrystal has been detected both by absorption spectroscopy and measurements of the refractive index under the influence of terrestrial solar radiation or using UV-C sources. In UV biological dosimetry the UV dose scale is additive starting at a value of zero according to the definition of CIE (Technical Report TC-6-18). The biological dose can be defined by a measured end-effect. In our dosimeters (phage T7 and uracil dosimeter) exposed to natural (terrestrial) UV radiation the proportion of pyrimidin photoproducts among the total photoproducts is smaller than 0.1 and the linear correlation between the biological and physical dose is higher than 0.9. According to the experimental data this linear relationship is often not valid. We observed that UV radiation did not only induce dimerisation but shorter wavelengths caused monomerisation of pyrimidin dimers. Performing the irradiation in oxygen free environment and using a Deuterium lamp as UV source, we could increase monomerisation against dimerisation thus the DNA-based dosimetrySs additivity rule is not fulfilled in these conditions. In this study we will demonstrate those non-linear experiments which constitute the basis of our biological experiments on the International Space Station.

  7. The effect of irradiation temperatures between ambient and 80 deg. C on the response of alanine dosimeters

    DEFF Research Database (Denmark)

    Sharpe, P.H.G.; Miller, Arne; Sephton, J.P.;

    2009-01-01

    Published data on the effect of irradiation temperature on the response of alanine dosimeters does not extend to the temperatures that may be experienced in high-dose industrial irradiations, particularly in the case of electron beams. We describe here results of the irradiation of alanine...... begins to deviate significantly from linearity and shows marked dose dependence. The effect of this behaviour under conditions typically experienced in industrial processing is evaluated and recommendations made concerning the use of alanine dosimeters at high doses and temperatures....

  8. Characteristics of radiophotoluminescent glass dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Masashi; Shiraishi, Akemi; Murakami, Hiroyuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-07-01

    In Japan Atomic Energy Research Institute, a film badge is recently replaced by a new type radiophotoluminescent (RPL) glass dosimeter for external personal monitoring. Some fundamental characteristics of this dosimeter, such as dose dependence linearity, energy dependence, angular dependence, dose evaluation accuracy at mixed irradiation conditions, fading, etc., were examined at the Facility of Radiation Standard (FRS), JAERI. The results have proved that the RPL glass dosimeter has sufficient characteristics for practical use as a personal dosimeter for all of the items examined. (author)

  9. Electronic UV dosimeters.

    Science.gov (United States)

    Wulf, H C; Gniadecka, M

    1996-08-01

    The pathogenic role of ultraviolet (UV) in the development of skin cancer, skin ageing and immunosuppression makes it important to monitor human exposure to UV radiation. In a previous study we constructed UVB and UVC dosimeters based on a thermoluminescent phenomenon induced by UV in CaF2 :Dy and CaF2 crystals. However, these dosimeters were insensitive to UVA radiation and readout was time-consuming. In the present study we aimed to develop an electronic dosimeter suitable for UVA, UVB and UVC. The principle of this dosimeter is a measure of accumulated electric current induced by UV on a photodetector. Electric current induced by UV on a photodetector was accumulated in a Plessey's E-cell coulometer. A special reading device was constructed to quantify total charge of the coulometer. Sensitivity for UVA, UVB and UVC was achieved by the use of appropriate filters in front of the photodetector. The sensitivity of the electronic dosimeter increased with increasing wavelength of UV radiation; therefore, in UVB and UVC dosimeters the use of amplifiers was necessary. A linear response to UVA, UVB and UVC was achieved. Dosimeters with a linear response to increasing doses of UVA, UVB and UVC have been constructed for personal monitoring of UV exposure.

  10. Small field diode correction factors derived using an air core fibre optic scintillation dosimeter and EBT2 film.

    Science.gov (United States)

    Ralston, Anna; Liu, Paul; Warrener, Kirbie; McKenzie, David; Suchowerska, Natalka

    2012-05-07

    There is no commercially available real-time dosimeter that can accurately measure output factors for field sizes down to 4 mm without the use of correction factors. Silicon diode detectors are commonly used but are not dosimetrically water equivalent, resulting in energy dependence and fluence perturbation. In contrast, plastic scintillators are nearly dosimetrically water equivalent. A fibre optic dosimeter (FOD) with a 0.8 mm(3) plastic scintillator coupled to an air core light guide was used to measure the output factors for Novalis/BrainLab stereotactic cones of diameter 4-30 mm and Novalis MLC fields of width 5-100 mm. The FOD data matched the output factors measured by a 0.125 cm(3) Semiflex ion chamber for the MLC fields above 30 mm and those measured with the EBT2 radiochromic film for the cones and MLC fields below 30 mm. Relative detector readings were obtained with four diode types (IBA SFD, EFD, PFD, PTW 60012) for the same fields. Empirical diode correction factors were determined by taking the ratio of FOD output factors to diode relative detector readings. The diodes were found to over-respond by 3%-16% for the smallest field. There was good agreement between different diodes of the same model number.

  11. MCz diode response as a high-dose gamma radiation dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, F. [Instituto de Pesquisas Energeticas e Nucleares-IPEN-CNEN/SP, Caixa Postal 11049 - 05422 970 Sao Paulo/SP (Brazil); Goncalves, J.A.C. [Instituto de Pesquisas Energeticas e Nucleares-IPEN-CNEN/SP, Caixa Postal 11049 - 05422 970 Sao Paulo/SP (Brazil); Depto. de Fisica, Pontificia Universidade Catolica de Sao Paulo-PUC/SP, Rua Marques de Paranagua no 111-01303 050 Sao Paulo/SP (Brazil); Khoury, H.J. [Nuclear Energy Department, Universidade Federal de Pernambuco-UFPE, Av. Prof. Luiz Freire no 1000-50740 540 Recife/PE (Brazil); Napolitano, C.M. [Instituto de Pesquisas Energeticas e Nucleares-IPEN-CNEN/SP, Caixa Postal 11049 - 05422 970 Sao Paulo/SP (Brazil); Haerkoenen, J. [Helsinki Institute of Physics-HIP, University of Helsinki, 00014 Helsinki (Finland); Bueno, C.C. [Instituto de Pesquisas Energeticas e Nucleares-IPEN-CNEN/SP, Caixa Postal 11049 - 05422 970 Sao Paulo/SP (Brazil); Depto. de Fisica, Pontificia Universidade Catolica de Sao Paulo-PUC/SP, Rua Marques de Paranagua no 111-01303 050 Sao Paulo/SP (Brazil)], E-mail: ccbueno@ipen.br

    2008-02-15

    This work presents the preliminary results obtained with a high-resistivity magnetic Czochralski (MCz) silicon diode processed at the Helsinki Institute of Physics as a high-dose gamma dosimeter in radiation processing. The irradiation was performed using a {sup 60}Co source (Gammacell 220, MDS Nordion) within total doses from 100 Gy up to 3 kGy at a dose rate of 3 kGy/h. In this interval, the dosimetric response of the diode is linear with a correlation coefficient (r{sup 2}) higher than 0.993. However, without any irradiation procedure, the device showed a small sensitivity dependence on the accumulated dose. For total dose of 3 kGy, the observed decrease was about 2%. To clarify the origin of this possible radiation damage effect, some studies are under way.

  12. Response of the DIS-1 personal dosimeter to neutrons, protons and other hadrons

    CERN Document Server

    Otto, Thomas

    2010-01-01

    The DIS-1 personal dosimeter is approved for assessment of personal dose Hp(10) and Hp(0.07) from γ and β radiation. Dose measurement in the DIS-1 is based on miniaturized ionization chambers. In mixed radiation fields with components other than photons and electrons, the dosimeter will not indicate personal dose, but the ionization chambers will produce a spurious signal that will add to the signal from γ and β radiation. The purpose of this paper is the evaluation of the magnitude of the spurious signal from other radiation types. For this purpose, irradiations of DIS-1 dosimeters were performed in a neutron calibration field and two mixed radiation fields at a particle accelerator. The results show, that the DIS-1 dosimeter indicates absorbed dose in arbitrary radiation fields. This property of the DIS-1 dosimeter can give critical information after accidental exposures or when investigating suspected overexposures.

  13. Investigation of the response characteristics of OSL albedo neutron dosimeters in a 241AmBe reference neutron field

    Science.gov (United States)

    Liamsuwan, T.; Wonglee, S.; Channuie, J.; Esoa, J.; Monthonwattana, S.

    2017-06-01

    The objective of this work was to systematically investigate the response characteristics of optically stimulated luminescence Albedo neutron (OSLN) dosimeters to ensure reliable personal dosimetry service provided by Thailand Institute of Nuclear Technology (TINT). Several batches of InLight® OSLN dosimeters were irradiated in a reference neutron field generated by the in-house 241AmBe neutron irradiator. The OSL signals were typically measured 24 hours after irradiation using the InLight® Auto 200 Reader. Based on known values of delivered neutron dose equivalent, the reading correction factor to be used by the reader was evaluated. Subsequently, batch homogeneity, dose linearity, lower limit of detection and fading of the OSLN dosimeters were examined. Batch homogeneity was evaluated to be 0.12 ± 0.05. The neutron dose response exhibited a linear relationship (R2=0.9974) within the detectable neutron dose equivalent range under test (0.4-3 mSv). For this neutron field, the lower limit of detection was between 0.2 and 0.4 mSv. Over different post-irradiation storage times of up to 180 days, the readings fluctuated within ±5%. Personal dosimetry based on the investigated OSLN dosimeter is considered to be reliable under similar neutron exposure conditions, i.e. similar neutron energy spectra and dose equivalent values.

  14. Calculation of the Energy Dependence of Dosimeter Response to Ionizing Photons

    DEFF Research Database (Denmark)

    Miller, Arne; McLaughlin, W. L.

    1982-01-01

    Using a program in BASIC applied to a desk-top calculator, simplified calculations provide approximate energy dependence correction factors of dosimeter readings of absorbed dose according to Bragg-Gray cavity theories. Burlin's general cavity theory is applied in the present calculations, and ce...... as given here are available for certain dosimeter probe materials and combinations used with intermediate energy photon spectra (0.01–100 MeV)....

  15. A 'quad-phantom' film dosimeter for use as a multi-planar verification tool for PRESAGE/optical-CT.

    Science.gov (United States)

    Stunja, L; Thomas, A; Adamovics, J; Deasy, J; Oldham, M

    2010-01-01

    INTRODUCTION: To develop and characterize the accuracy and reproducibility of a quad-phantom dosimeter which will serve as an independent verification tool during commissioning of a PRESAGE/optical-CT 3D dosimetry system. METHODS: A 16cm × 12cm cylindrical quad-phantom was constructed from four pieces of solid polyurethane mimicking the PRESAGE material. Films were placed and anchored in orthogonal planes and the quad-phantom was fastened tightly together and placed in a water-filled Styrofoam container for irradiation. A simple, two-field plan consisting of 6×6cm anterior-posterior and right-lateral 6MV photon beams (400cGy) was delivered three times (fresh films inserted for each) with a Varian Clinac 600C. Image registration was performed in the Computational Environment for Radiological Research (CERR) and dose profiles and gamma analysis was performed in CERR and MATLAB. RESULTS #ENTITYSTARTX00026; DISCUSSION: Excellent reproducibility was observed during the irradiations, with ~2.3% standard deviation between all pixels. Using a 3%, 3mm gamma criteria, excellent dosimetric accuracy was observed, with 98.8% and 96.3% passing rates in the sagittal and axial planes, respectively. CONCLUSION: The preliminary results indicate that the quad-phantom can serve as a reproducible and accurate system for high resolution dosimetry in orthogonal planes and should serve as an effective verification tool for PRESAGE/optical-CT in more challenging clinical scenarios.

  16. A 'quad-phantom' film dosimeter for use as a multi-planar verification tool for PRESAGE/optical-CT

    Science.gov (United States)

    Stunja, L.; Thomas, A.; Adamovics, J.; Deasy, J.; Oldham, M.

    2010-11-01

    Introduction: To develop and characterize the accuracy and reproducibility of a 'quad-phantom' dosimeter which will serve as an independent verification tool during commissioning of a PRESAGE/optical-CT 3D dosimetry system. Methods: A 16cm × 12cm cylindrical quad-phantom was constructed from four pieces of solid polyurethane mimicking the PRESAGE material. Films were placed and anchored in orthogonal planes and the quad-phantom was fastened tightly together and placed in a water-filled Styrofoam container for irradiation. A simple, two-field plan consisting of 6×6cm anterior-posterior and right-lateral 6MV photon beams (400cGy) was delivered three times (fresh films inserted for each) with a Varian Clinac 600C. Image registration was performed in the Computational Environment for Radiological Research (CERR) and dose profiles and gamma analysis was performed in CERR and MATLAB. Results & Discussion: Excellent reproducibility was observed during the irradiations, with ~2.3% standard deviation between all pixels. Using a 3%, 3mm gamma criteria, excellent dosimetric accuracy was observed, with 98.8% and 96.3% passing rates in the sagittal and axial planes, respectively. Conclusion: The preliminary results indicate that the quad-phantom can serve as a reproducible and accurate system for high resolution dosimetry in orthogonal planes and should serve as an effective verification tool for PRESAGE/optical-CT in more challenging clinical scenarios.

  17. Production and testing of a synthetic diamond film radiation dosimeter for radiotherapy

    CERN Document Server

    Fidanzio, A; Venanzi, C; Pinzari, F; Piermattei, A

    2002-01-01

    A detector, constituted by a polycrystalline chemical vapor deposited diamond film, has been made for on-line radiotherapy beam analysis in terms of dose distributions in water equivalent material. Preliminary results are reported which evidence that the leakage current can be a limiting parameter for an efficient collection of the charge carriers produced by the ionizing radiation. A signal to noise ratio near to 100 has been obtained. A priming effect similar to that found in natural diamond devices has also been evidenced, and a stable detector response was obtained after an accumulated dose of 5 Gy. The linearity has been achieved between the detector reading and the dose. The detector sensitivity resulted was equal to 77 nC/Gy per mm sup 3 of detector sensitive volume. A power law with exponent DELTA less than one has been found between detector reading and dose rate. However, when the dose rate dependence was corrected, the percentage depth doses, along an X-ray beam central axis, was in agreement with ...

  18. Optical properties of a long dynamic range chemical UV dosimeter based on solvent cast polyvinyl chloride (PVC).

    Science.gov (United States)

    Amar, Abdurazaq; Parisi, Alfio V

    2013-11-01

    The dosimetric properties of the recently introduced UV dosimeter based on 16 μm PVC film have been fully characterised. Drying the thin film in air at 50 °C for at least 28 days was found to be necessary to minimise the temperature effects on the dosimeter response. This research has found that the dosimeter response, previously reported to be mainly to UVB, has no significant dependence on either exposure temperature or dose rate. The dosimeter has negligible dark reaction and responds to the UV radiation with high reproducibility. The dosimeter angular response was found to have a similar pattern as the cosine function but deviates considerably at angles larger than 70°. Dose response curves exhibit monotonically increasing shape and the dosimeter can measure more than 900 SED. This is about 3 weeks of continuous exposure during summer at subtropical sites. Exposures measured by the PVC dosimeter for some anatomical sites exposed to solar radiation for twelve consecutive days were comparable with those concurrently measured by a series of PPO dosimeters and were in line with earlier results reported in similar studies.

  19. Characterization of the energy response and backscatter contribution for two electronic personal dosimeter models.

    Science.gov (United States)

    Meier, Joseph; Kappadath, S Cheenu

    2015-11-08

    We characterized the energy response of personal dose equivalent (Hp(10) in mrem) and the contribution of backscatter to the readings of two electronic personal dosimeter (EPD) models with radionuclides commonly used in a nuclear medicine clinic. The EPD models characterized were the RADOS RAD-60R, and the SAIC PD-10i. The experimental setup and calculation of EPD energy response was based on ANSI/HPS N13.11-2009. Fifteen RAD-60R and 2 PD-10i units were irradiated using (99m)Tc, (131)I, and (18)F radionuclides with emission energies at 140 keV, 364 keV, and 511 keV, respectively. At each energy, the EPDs output in Hp(10) [mrem] were recorded with 15 inch thick PMMA to simulate backscatter form the torso. Simultaneous free-in-air exposure rate measurements were also performed using two Victoreen ionization survey meters to calculate the expected EPD Hp(10) values per ANSI/HPS N13.11-2009. The energy response was calculated by taking the ratio of the EPD Hp(10) readings with the expected Hp(10) readings and a two-tailed z-test was used to determine the significance of the ratio deviating away from unity. The contribution from backscatter was calculated by taking the ratio of the EPD Hp(10) readings with and without backscatter material. A paired, two-tailed t-test was used to determine the significance of change in EPD Hp(10) readings. The RAD-60R mean energy response at 140 keV was 0.85, and agreed to within 5% and 11% at 364 and 511 keV, respectively. The PD-10i mean energy response at 140 keV was 1.20, and agreed to within 5% at 364 and 511 keV, respectively. On average, in the presence of acrylic, RAD-60R values increased by 32%, 12%, and 14%, at 140, 364, and 511 keV, respectively; all increases were statistically significant. The PD-10i increased by 25%, 19%, and 10% at 140 keV, 364 keV, and 511 keV, respectively; however, only the 140 keV measurement was statistically significant. Although both EPD models performed within the manufacturers' specifications of

  20. The response of a radiophotoluminescent glass dosimeter in megavoltage photon and electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Araki, Fujio, E-mail: f-araki@kumamoto-u.ac.jp; Ohno, Takeshi [Department of Health Sciences, Faculty of Life Sciences, Kumamoto University, 4-24-1 Kuhonji, Chuo-ku, Kumamoto 862-0976 (Japan)

    2014-12-15

    Purpose: This study investigated the response of a radiophotoluminescent glass dosimeter (RGD) in megavoltage photon and electron beams. Methods: The RGD response was compared with ion chamber measurements for 4–18 MV photons and 6–20 MeV electrons in plastic water phantoms. The response was also calculated via Monte Carlo (MC) simulations with EGSnrc/egs-chamber and Cavity user-codes, respectively. In addition, the response of the RGD cavity was analyzed as a function of field sizes and depths according to Burlin’s general cavity theory. The perturbation correction factor, P{sub Q}, in the RGD cavity was also estimated from MC simulations for photon and electron beams. Results: The calculated and measured RGD energy response at reference conditions with a 10 × 10 cm{sup 2} field and 10 cm depth in photons was lower by up to 2.5% with increasing energy. The variation in RGD response in the field size range of 5 × 5 cm{sup 2} to 20 × 20 cm{sup 2} was 3.9% and 0.7%, at 10 cm depth for 4 and 18 MV, respectively. The depth dependence of the RGD response was constant within 1% for energies above 6 MV but it increased by 2.6% and 1.6% for a large (20 × 20 cm{sup 2}) field at 4 and 6 MV, respectively. The dose contributions from photon interactions (1 − d) in the RGD cavity, according to Burlin’s cavity theory, decreased with increasing energy and decreasing field size. The variation in (1 − d) between field sizes became larger with increasing depth for the lower energies of 4 and 6 MV. P{sub Q} for the RGD cavity was almost constant between 0.96 and 0.97 at 10 MV energies and above. Meanwhile, P{sub Q} depends strongly on field size and depth for 4 and 6 MV photons. In electron beams, the RGD response at a reference depth, d{sub ref}, varied by less than 1% over the electron energy range but was on average 4% lower than the response for 6 MV photons. Conclusions: The RGD response for photon beams depends on both (1 − d) and perturbation effects in the

  1. Response of thermoluminescent dosimeters to photons simulated with the Monte Carlo method

    Science.gov (United States)

    Moralles, M.; Guimarães, C. C.; Okuno, E.

    2005-06-01

    Personal monitors composed of thermoluminescent dosimeters (TLDs) made of natural fluorite (CaF 2:NaCl) and lithium fluoride (Harshaw TLD-100) were exposed to gamma and X rays of different qualities. The GEANT4 radiation transport Monte Carlo toolkit was employed to calculate the energy depth deposition profile in the TLDs. X-ray spectra of the ISO/4037-1 narrow-spectrum series, with peak voltage (kVp) values in the range 20-300 kV, were obtained by simulating a X-ray Philips MG-450 tube associated with the recommended filters. A realistic photon distribution of a 60Co radiotherapy source was taken from results of Monte Carlo simulations found in the literature. Comparison between simulated and experimental results revealed that the attenuation of emitted light in the readout process of the fluorite dosimeter must be taken into account, while this effect is negligible for lithium fluoride. Differences between results obtained by heating the dosimeter from the irradiated side and from the opposite side allowed the determination of the light attenuation coefficient for CaF 2:NaCl (mass proportion 60:40) as 2.2 mm -1.

  2. Study of the relative dose-response of BANG-3® polymer gel dosimeters in epithermal neutron irradiation

    Science.gov (United States)

    Uusi-Simola, J.; Savolainen, S.; Kangasmäki, A.; Heikkinen, S.; Perkiö, J.; Abo Ramadan, U.; Seppälä, T.; Karila, J.; Serén, T.; Kotiluoto, P.; Sorvari, P.; Auterinen, I.

    2003-09-01

    Polymer gels have been reported as a new, potential tool for dosimetry in mixed neutron-gamma radiation fields. In this work, BANG-3 (MGS Research Inc.) gel vials from three production batches were irradiated with 6 MV photons of a Varian Clinac 2100 C linear accelerator and with the epithermal neutron beam of the Finnish boron neutron capture therapy (BNCT) facility at the FiR 1 nuclear reactor. The gel is tissue equivalent in main elemental composition and density and its T2 relaxation time is dependent on the absorbed dose. The T2 relaxation time map of the irradiated gel vials was measured with a 1.5 T magnetic resonance (MR) scanner using spin echo sequence. The absorbed doses of neutron irradiation were calculated using DORT computer code, and the accuracy of the calculational model was verified by measuring gamma ray dose rate with thermoluminescent dosimeters and 55Mn(n,gamma) activation reaction rate with activation detectors. The response of the BANG-3 gel dosimeter for total absorbed dose in the neutron irradiation was linear, and the magnitude of the response relative to the response in the photon irradiation was observed to vary between different gel batches. The results support the potential of polymer gels in BNCT dosimetry, especially for the verification of two- or three-dimensional dose distributions.

  3. Calibration of dosimeters at 80-120 keV electron irradiation

    DEFF Research Database (Denmark)

    Miller, A.; Helt-Hansen, J.

    We describe calorimeters for dose measurement at low-energy electron accelerator energies (80–120 keV). Three calorimeters with different characteristics were designed and their dose response and measurement uncertainties were characterized. The heatedair between the electron beam exit window...... to calibrate thin-film dosimeters (Risø B3 and alanine films) by irradiation at the 80–120 keV electron accelerators. This calibration was compared to a 10MeV calibration, and we show that the radiation response of the dosimeter materials (the radiation chemical yield) is constant at these irradiation energies...

  4. Study on the angular dependence of personal exposure dosimeter - Focus on thermoluminescent dosimeter and photoluminescent dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Kyung-Rae [Department of Radiological Technology, Gwangju Health College University (Korea, Republic of); Department of Nuclear Engineering, Chosun University (Korea, Republic of); Kweon, Dae Cheol [Department of Radiologic Science, Shin Heung College University (Korea, Republic of); Chung, Woon-Kwan, E-mail: wkchung@chosun.ac.kr [Department of Nuclear Engineering, Chosun University (Korea, Republic of); Goo, Eun-Hoe [Department of Diagnostic Radiology, Seoul National University Hospital (Korea, Republic of); Department of Physics, Soonchunhyang University (Korea, Republic of); Dieter, Kevin [Department of Physical Therapy, Gwangju Health College University (Korea, Republic of); Choe, Chong-Hwan [Department of White Memorial Medical Center (United States)

    2011-02-15

    Radiation management departments place more emphasis on the accuracy of measurements than on the increase in the average dose and personal exposure dose from the use of radiation equipment and radioactive isotopes. Although current measurements are taken using devices, such as film badge dosimeters, pocket dosimeters and thermoluminescent dosimeters (TLDs), this study compared the angular dependence between the widely used TLDs and photoluminescent dosimeter (PLDs) in order to present primary data and evaluate the utility of PLD as a new dosimeter device. For X-ray fluoroscopy, a whole body phantom was placed on a table with a setting for the G-I technical factors fixed at a range of approximately 40 cm with a range of {+-}90{sup o} at an interval scale of 15{sup o} from the center location of an average radiological worker for PLDs (GD-450) and TLDs (Carot). This process was repeated 10 times, and at each time, the cumulative dosage was interpreted from 130 dosimeters using TLDs (UD-710R, Panasonic) and PLDs (FGD-650). The TLD and PLD showed a 52% and 23% decrease in the depth dosage from 0{sup o} to -90{sup o}, respectively. Therefore, PLDs have a lower angular dependence than TLDs.

  5. The use of oscillometry as a measure of airway responsiveness in asthmatic children after histamine and methacholine bronchoprovocation with dosimeter-MedicAid and DeVilbiss nebulizers.

    Science.gov (United States)

    Kopriva, F; Szotkowská, J; Plocová, A; Závodská, J; Zápalka, M; Smatanová, D; Látalová, M; Slezáková, L; Radová, L

    2007-05-01

    To explore the use of oscillometry as a measure of airway responsiveness, 69 asthmatic children underwent histamine and methacholine bronchoprovocation using dosimeter-MedicAid (Jaeger Co.; Germany) and DeVilbiss nebulizers (DeVilbiss, Bornemouth; England). The mean increase in R5 resistance in challenge testing measured after methacholine with the dosimeter-MedicAid nebulizer was 77.14% compared with 65.05% using histamine. Using the dosimeter-DeVilbiss nebulizer, the mean increases in R5 resistance following methacholine and histamine testing were 57.50% and 59.36%, respectively. The resistance R5 over R20 significantly correlated with forced expiratory volume in 1 second (FEV1). The MedicAid produced a more aggressive challenge than the DeVilbliss nebulizer. Oscillometry can be used to monitor the level of airway hyperresponsiveness following bronchoprovocation tests.

  6. OSL and Tl response characterization of micro LiF:Mg, Ti dosimeters to be applied to VMAT quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Bravim, A.; Campos, L. L. [Instituto de Pesquisas Energeticas e Nucleares / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil); Sakuraba, R. K.; Da Cruz, J. C., E-mail: ambravim@hotmail.com [Sociedade Beneficente Israelita Brasileira - Hospital Albert Einstein, Av. Albert Einstein 627/701, Jardim Leonor, 05652-900 Sao Paulo (Brazil)

    2014-08-15

    VMAT Rapid Arc is a new method of treatment responsible for a change in the setting of radiotherapy, bringing benefits and allowing a lower toxicity in the treatment of patients. With this treatment is possible to minimize the radiation dose to the healthy tissues and escalate the dose to the target volume (tumor) (Hall, 1998; Mundt, 2005; Bortfeld, 2006). The quality assurance is essential to verify the operation of all components involved in the process of treatment planning and dose delivery. Several organizations recommended the verification of patient dose for quality improvement in radiotherapy and the recommended maximum values for the uncertainty in the dose range of ± 5% (ICRU, 1976, AAPM, 1983). This paper aims to evaluate the feasibility of applying LiF:Mg,Ti micro dosimeters as a new method of dosimetry to VMAT Rapid Arc. (Author)

  7. Visible absorption spectra of radiation exposed SIRAD dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Butson, Martin J [Department of Physics and Materials Science, City University of Hong Kong, Kowloon Tong, Hong Kong (China); Cheung Tsang [Department of Physics and Materials Science, City University of Hong Kong, Kowloon Tong, Hong Kong (China); Yu, Peter K N [Department of Physics and Materials Science, City University of Hong Kong, Kowloon Tong, Hong Kong (China)

    2006-12-07

    SIRAD badge dosimeters are a new type of personal dosimeter designed to measure radiation exposure up to 200 R and give a visual qualitative measurement of exposure. This is performed using the active dosimeter window, which contains a radiochromic material amalgamated in the badge assembly. When irradiated, the badges active window turns blue, which can be matched against the given colour chart for a qualitative assessment of the exposure received. Measurements have been performed to analyse the absorption spectra of the active window, and results show that the window automatically turns a blue colour upon irradiation and produces two peaks in the absorption spectra located at 617 nm and 567 nm. When analysed with a common computer desktop scanner, the optical density response of the film to radiation exposure is non-linear but reproducible. The net OD of the film was 0.21 at 50 R exposure and 0.31 at 200 R exposure when irradiated with a 6 MV x-ray energy beam. When compared to the calibration colour strips at 6 MV x-ray energy the film's OD response matches relatively well within 3.5%. An approximate 8% reduction in measured OD to exposure was seen for 250 kVp x-rays compared to 6 MV x-rays. The film provides an adequate measurement and visually qualitative assessment of radiation exposure for levels in the range of 0 to 200 R. (note)

  8. Response of TLD-100 LiF dosimeters for X-rays of low energies; Respuesta de dosimetros de TLD-100 de LiF para rayos X de bajas energias

    Energy Technology Data Exchange (ETDEWEB)

    Bonzi, E. V.; Mainardi, R. T. [Universidad Nacional de Cordoba, Facultad de Matematica, Astronomia y Fisica, Av. Haya de la Torre y Av. Medina Allende s/n, Ciudad Universitaria, X5016LEA Cordoba (Argentina)

    2011-10-15

    In diverse practical applications as the existent in radiological clinics, industrial facilities and research laboratories, the solid state dosimeters are used for the measure of the different types of ionizing radiations. At the present time dosimeters are manufactured with different types of materials that present thermoluminescent properties, to the effects of determining the absorbed radiation dose. Under these conditions, the radiation dose is determined integrated in all the range of energies of the beam of X-rays, since it assumes that the response of these dosimeters is lineal with the energy of the photons or radiant particles. Because interest exists in advancing in the development of a determination method in the way of the X-rays spectrum emitted by a tube of those used in diagnostic or therapy, we have measured the response of TLD-100 LiF dosimeters for low energies, minor at 60 keV, for a several group of these dosimeters. (Author)

  9. The effect of a compression paddle on energy response, calibration and measurement with mammographic dosimeters using ionization chambers and solid-state detectors.

    Science.gov (United States)

    Hourdakis, C J; Boziari, A; Koumbouli, E

    2009-02-21

    A compression paddle is always used in mammography x-ray examinations, in order to improve image quality and reduce patient doses. Although clinical dose measurements should be performed with the paddle to interfere with the x-ray beam, calibration of mammography dosimeters is performed free in air without the presence of the paddle. The paddle hardens the x-ray beam, which has an impact on a dosimeter performance, particularly on high-energy-dependent detectors. Due to the paddle, clinical mammography x-ray systems may exhibit beams with HVL values exceeding those of the IEC 61267 RQR-M series qualities at which dosimeters are usually calibrated. In this study, the influence of the paddle in mammography dosimetry is examined, in Mo/Mo anode/filter x-ray qualities. PMMA slabs of 1, 2 and 3 mm thickness and Al foils of 0.05, 0.10 and 0.15 mm thicknesses were used to simulate the paddles, producing beams with HVL values from 0.28 up to 0.43 mmAl. In these qualities, four solid-state (ST) detectors and three ionizations chambers (IC) were calibrated in terms of Kair and N(K) and k(Q) were deduced. The results showed that all IC and two modern-type ST dosimeters have a flat energy response in the above HVL range (less than 3%), so their calibration factor at RQR-M2 quality could be safely used for clinical measurements. Two other ST dosimeters exhibit up to 20% energy response, so differences up to 15% in dose measurement may be observed if the effect of paddle on their performance is ignored. Finally, the need of additional mammographic calibration qualities to the existing IEC 61267 RQR-M series is examined and discussed.

  10. The Response of an Albedo Neutron Dosimeter to Moderated AmBe and 252(Cf) Neutron Sources.

    Science.gov (United States)

    2014-09-26

    neutrons is deter- mined by making multiple integrations on the glow curves from the detectors [41, or by computer analysis of the glow curves [5-61...Falk, "A Personnel Neutron Dosimeter Using Lithium Fluoride Thermoluminescent Dosim- eters," Report No. RFP-1581, Dow Chemical Co., Golden CO (1971...Addison Wesley, Reading, MA, 1953). 18. D.E. Hankins, "Factors Affecting the Design of Albedo Neutron Dosimeters Containing Lithium Fluoride

  11. Effects of the pre-irradiation storage procedure on the dose response of a Fricke xylenol orange gel dosimeter

    Directory of Open Access Journals (Sweden)

    Liosi Giulia Maria

    2015-09-01

    Full Text Available The Fricke xylenol orange (FX gel system is a chemical dosimeter characterized by good sensitivity, linear dose response, tissue equivalence, no toxicity, easy preparation, reproducibility and low cost. Thanks to the presence of the gelatinous matrix, the system is particularly suitable to perform reliable 3D mapping of the absorbed dose spatial distribution via magnetic resonance imaging (MRI or optical techniques. The aim of this work is to study in a systematic way the influence of the pre-irradiation storage procedure upon sensitivity, dose response stability and lifetime of use of a FX gel system made with gelatin from porcine skin subjected to homogeneous irradiation. For this purpose, different pre-irradiation storage procedures, in terms of temperature and duration of each storage step, were investigated. In order to evaluate the dose response stability, the optical analyses of the samples were performed up to 6 hours after irradiation. Moreover, the samples were irradiated at time intervals of 24 hours for up to 7 days after preparation in order to evaluate the system lifetime of use. Regardless of their thermal and temporal life, the samples show linear dose responses in the investigated dose range (3-24 Gy and an increase of sensitivity with the time elapsed between preparation and irradiation. Among the three pre-irradiation storage procedures considered here, a procedure that provides the best dose response stability and lifetime of use was identified and recommended for further use. The analyzed dosimetric system possesses good properties that make it promising for medical application, particularly concerning the evaluation of pre-treatment plan quality assurance within the conformational external beam radiotherapy

  12. A comprehensive study on the photon energy response of RadFET dosimeters using the PENELOPE Monte Carlo code

    Science.gov (United States)

    Kahraman, A.; Kaya, S.; Jaksic, A.; Yilmaz, E.

    2015-05-01

    Radiation-sensing Field Effect Transistors (RadFETs or MOSFET dosimeters) with SiO2 gate dielectric have found applications in space, radiotherapy clinics, and high-energy physics laboratories. More sensitive RadFETs, which require modifications in device design, including gate dielectric, are being considered for personal dosimetry applications. This paper presents results of a detailed study of the RadFET energy response simulated with PENELOPE Monte Carlo code. Alternative materials to SiO2 were investigated to develop high-efficiency new radiation sensors. Namely, in addition to SiO2, Al2O3 and HfO2 were simulated as gate material and deposited energy amounts in these layers were determined for photon irradiation with energies between 20 keV and 5 MeV. The simulations were performed for capped and uncapped configurations of devices irradiated by point and extended sources, the surface area of which is the same with that of the RadFETs. Energy distributions of transmitted and backscattered photons were estimated using impact detectors to provide information about particle fluxes within the geometrical structures. The absorbed energy values in the RadFETs material zones were recorded. For photons with low and medium energies, the physical processes that affect the absorbed energy values in different gate materials are discussed on the basis of modelling results. The results show that HfO2 is the most promising of the simulated gate materials.

  13. A ‘quad-phantom’ film dosimeter for use as a multi-planar verification tool for PRESAGE/optical-CT

    Science.gov (United States)

    Stunja, L; Thomas, A; Adamovics, J; Deasy, J; Oldham, M

    2010-01-01

    Introduction To develop and characterize the accuracy and reproducibility of a quad-phantom dosimeter which will serve as an independent verification tool during commissioning of a PRESAGE/optical-CT 3D dosimetry system. Methods A 16cm × 12cm cylindrical quad-phantom was constructed from four pieces of solid polyurethane mimicking the PRESAGE material. Films were placed and anchored in orthogonal planes and the quad-phantom was fastened tightly together and placed in a water-filled Styrofoam container for irradiation. A simple, two-field plan consisting of 6×6cm anterior-posterior and right-lateral 6MV photon beams (400cGy) was delivered three times (fresh films inserted for each) with a Varian Clinac 600C. Image registration was performed in the Computational Environment for Radiological Research (CERR) and dose profiles and gamma analysis was performed in CERR and MATLAB. Results & Discussion Excellent reproducibility was observed during the irradiations, with ~2.3% standard deviation between all pixels. Using a 3%, 3mm gamma criteria, excellent dosimetric accuracy was observed, with 98.8% and 96.3% passing rates in the sagittal and axial planes, respectively. Conclusion The preliminary results indicate that the quad-phantom can serve as a reproducible and accurate system for high resolution dosimetry in orthogonal planes and should serve as an effective verification tool for PRESAGE/optical-CT in more challenging clinical scenarios. PMID:21218141

  14. A 'quad-phantom' film dosimeter for use as a multi-planar verification tool for PRESAGE/optical-CT

    Energy Technology Data Exchange (ETDEWEB)

    Stunja, L; Thomas, A; Adamovics, J; Deasy, J; Oldham, M, E-mail: les34@duke.ed

    2010-11-01

    Introduction: To develop and characterize the accuracy and reproducibility of a 'quad-phantom' dosimeter which will serve as an independent verification tool during commissioning of a PRESAGE/optical-CT 3D dosimetry system. Methods: A 16cm x 12cm cylindrical quad-phantom was constructed from four pieces of solid polyurethane mimicking the PRESAGE material. Films were placed and anchored in orthogonal planes and the quad-phantom was fastened tightly together and placed in a water-filled Styrofoam container for irradiation. A simple, two-field plan consisting of 6x6cm anterior-posterior and right-lateral 6 MV photon beams (400 cGy) was delivered three times (fresh films inserted for each) with a Varian Clinac 600C. Image registration was performed in the Computational Environment for Radiological Research (CERR) and dose profiles and gamma analysis was performed in CERR and MATLAB. Results and Discussion: Excellent reproducibility was observed during the irradiations, with {approx}2.3% standard deviation between all pixels. Using a 3%, 3mm gamma criteria, excellent dosimetric accuracy was observed, with 98.8% and 96.3% passing rates in the sagittal and axial planes, respectively. Conclusion: The preliminary results indicate that the quad-phantom can serve as a reproducible and accurate system for high resolution dosimetry in orthogonal planes and should serve as an effective verification tool for PRESAGE/optical-CT in more challenging clinical scenarios.

  15. The shelf life of dyed polymethylmethacrylate dosimeters

    Science.gov (United States)

    Bett, R.; Watts, M. F.; Plested, M. E.

    2002-03-01

    The long-term stability of the radiation response of Harwell Red 4034 and Amber 3042 Perspex Dosimeters has been monitored for more than 15 years, and the resulting data used in the justification of their shelf-life specifications.

  16. Use of borated polyethylene to improve low energy response of a prompt gamma based neutron dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Priyada, P.; Ashwini, U.; Sarkar, P.K., E-mail: pradip.sarkar@manipal.edu

    2016-05-21

    The feasibility of using a combined sample of borated polyethylene and normal polyethylene to estimate neutron ambient dose equivalent from measured prompt gamma emissions is investigated theoretically to demonstrate improvements in low energy neutron dose response compared to only polyethylene. Monte Carlo simulations have been carried out using the FLUKA code to calculate the response of boron, hydrogen and carbon prompt gamma emissions to mono energetic neutrons. The weighted least square method is employed to arrive at the best linear combination of these responses that approximates the ICRP fluence to dose conversion coefficients well in the energy range of 10{sup −8} MeV to 14 MeV. The configuration of the combined system is optimized through FLUKA simulations. The proposed method is validated theoretically with five different workplace neutron spectra with satisfactory outcome. - Highlights: • An improved method is proposed for estimating H⁎(10) using prompt gamma emissions. • A combination of BHDPE and HDPE cylinders is used as a sample. • Linear combination of prompt gamma intensities approximates ICRP-DCC closely. • Feasibility of the method was tested theoretically using workplace neutron spectra.

  17. Description and evaluation of the Hanford personnel dosimeter program from 1944 through 1989. [Contain Glossary

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, R.H.; Fix, J.J.; Baumgartner, W.V.; Nichols, L.L.

    1990-09-01

    This report describes the evolution of personnel dosimeter technology at Hanford since the inception of Hanford operations in 1944. Each of the personnel dosimeter systems used by people working or visiting Hanford is described. In addition, the procedures used to calibrate and calculate dose for each of the dosimeter systems are described. The accuracy of the recorded dose, primarily whole body deep dose, for the different dosimeter systems is evaluated. The evaluation is based on an extensive review of historical literature, as well as a 1989 intercomparison study of all film dosimeters and performance testing of the thermoluminescent dosimeter, also conducted during 1989. 73 refs., 40 figs., 41 tabs.

  18. A method for the quantitative analysis of Intensity-Modulated Radiation Therapy (IMRT) treatment plan verification with radiographic film and polymer gel dosimeters

    Science.gov (United States)

    Witten, Matthew Roy

    The clinical implementation of intensity-modulated radiotherapy has necessitated the development of sophisticated quality assurance techniques to ensure that the radiation dose distribution calculated by the computerized radiotherapy treatment planning system is reproduced with an acceptable degree of fidelity during treatment delivery. The index of agreement is introduced as a quantitative quality assurance tool capable of comparing the planned dose distribution with the dose distribution measured with a radiation dosimeter. The index of agreement method begins with solving a constrained optimization problem for each pixel (or voxel) of the planned dose distribution. Each pixel (or voxel) of the planned distribution is then assigned a score based upon the solution of the constrained optimization problem. The index of agreement is then calculated by dividing the number of pixels (or voxels) that are clinically relevant and for which the score function is equal to zero by the total number of clinically relevant pixels (or voxels). Data acquired with radiographic film and polymer gel indicate that the index of agreement is a stable quality assurance parameter.

  19. Response of bacteriophage T7 biological dosimeter to dehydration and extraterrestrial solar UV radiation

    Science.gov (United States)

    Hegedüs, M.; Fekete, A.; Módos, K.; Kovács, G.; Rontó, Gy.; Lammer, H.; Panitz, C.

    2007-02-01

    The experiment "Phage and uracil response" (PUR) will be accommodated in the EXPOSE facility of the ISS. Bacteriophage T7/isolated T7 DNA will be exposed to different subsets of extreme environmental parameters in space, in order to study the Responses of Organisms to the Space Environment (ROSE). Launch into orbit is preceded by EXPOSE Experiment Verification Tests (EVT) to optimize the methods and the evaluation. Bacteriophage T7/isolated T7 DNA thin layers were exposed to vacuum ( 10-6Pa), to monochromatic (254 nm) and polychromatic (200-400 nm) UV radiation in air as well as in simulated space vacuum. Using neutral density (ND) filters dose-effect curves were performed in order to define the maximum doses tolerated. The effect of temperature fluctuation in vacuum was also studied. The structural/chemical effects on bacteriophage T7/isolated T7 DNA were analyzed by spectroscopic and microscopical methods. Characteristic changes in the absorption spectrum and in the electrophoretic pattern of phage/DNA have been detected indicating the damage of isolated and intraphage DNA. DNA damage was also determined by quantitative PCR (QPCR) using 555 and 3826 bp fragments of T7 DNA. We obtained substantial evidence that DNA lesions (e.g. strand breaks, DNA-protein cross-links, cyclobutane pirimidine dimers (CPDs) etc.) accumulate throughout exposure. Preliminary results suggest a synergistic action of space vacuum and UV radiation with DNA being the critical target.

  20. Micromechanical radiation dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Thundat, T.; Sharp, S.L.; Fisher, W.G.; Warmack, R.J.; Wachter, E.A. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6123 (United States))

    1995-03-20

    We demonstrate the use of microcantilevers coated with ultraviolet cross-linking polymers as optical radiation dosimeters. Upon exposure to radiation, a treated cantilever bends due to stress and its resonance frequency increases due to stiffening. These phenomena can be used to develop sensitive radiation dosimeters which respond to radiation affecting the mechanical properties of the selected coating.

  1. NOTE: Study of Gafchromic® EBT film response over a large dose range

    Science.gov (United States)

    Martišíková, Mária; Jäkel, Oliver

    2010-05-01

    Presently Gafchromic EBT films are widely used for relative dose verification in standard radiation therapy using high-energy photons, inclusive IMRT. The use of films for dosimetry in medical ion beams is more complicated due to the strongly inhomogeneous dose deposition by ions on microscopic level. Track structure models, presently used to describe dosimeter response as a function of the ion field properties, are based on input information which can be obtained from the film response in photon beams. We therefore studied the performance of Gafchromic EBT films, ancestors of currently available EBT2 films, in 60Co photon beams. The dose-response curve was measured from 7.5 × 10-2 Gy to 3 × 104 Gy. The dynamic range, linearity and dose rate dependence of this calibration curve were studied. A high saturation dose of 3 × 103 Gy, and thus a large dynamic range, was observed. No signs of supralinearity and bleaching due to radiation were found. No dependence of the response on the dose rate at high dose rates and high doses was found. All those properties justify the use of simplified models of the film response to ions. Furthermore, fits of the calibration data by predictions of different models for signal creation mechanism of dosimetric materials were performed. The best description was found for the recently published gamma-distributed single-hit model which takes into account different sizes of the active centres.

  2. Sensitivity and variability of Presage dosimeter formulations in sheet form with application to SBRT and SRS QA

    Energy Technology Data Exchange (ETDEWEB)

    Dumas, Michael, E-mail: mdumas1127@gmail.com [Department of Radiation Oncology, Wayne State University School of Medicine and Karmanos Cancer Institute Detroit, Detroit, Michigan 48201 and Department of Radiation Oncology, Henry Ford Hospital, Detroit, Michigan 48202 (United States); Rakowski, Joseph T. [Department of Radiation Oncology, Wayne State University School of Medicine and Karmanos Cancer Institute Detroit, Detroit, Michigan 48201 (United States)

    2015-12-15

    Purpose: To measure sensitivity and stability of the Presage dosimeter in sheet form for various chemical concentrations over a range of clinical photon energies and examine its use for stereotactic body radiation therapy (SBRT) and stereotactic radiosurgery (SRS) QA. Methods: Presage polymer dosimeters were formulated to investigate and optimize their sensitivity and stability. The dosimeter is composed of clear polyurethane base, leucomalachite green (LMG) reporting dye, and bromoform radical initiator in 0.9–1.0 mm thick sheets. The chemicals are mixed together for 2 min, cast in an aluminum mold, and left to cure at 60 psi for a minimum of two days. Dosimeter response was characterized at energies Co-60, 6 MV, 10 MV flattening-filter free, 15 MV, 50 kVp (mean 19.2 keV), and Ir-192. The dosimeters were scanned by a Microtek Scanmaker i800 at 300 dpi, 2{sup 16} bit depth per color channel. Red component images were analyzed with ImageJ and RIT. SBRT QA was done with gamma analysis tolerances of 2% and 2 mm DTA. Results: The sensitivity of the Presage dosimeter increased with increasing concentration of bromoform. Addition of tin catalyst decreased curing time and had negligible effect on sensitivity. LMG concentration should be at least as high as the bromoform, with ideal concentration being 2% wt. Gamma Knife SRS QA measurements of relative output and profile widths were within 2% of manufacturer’s values validated at commissioning, except the 4 mm collimator relative output which was within 3%. The gamma pass rate of Presage with SBRT was 73.7%, compared to 93.1% for EBT2 Gafchromic film. Conclusions: The Presage dosimeter in sheet form was capable of detecting radiation over all tested photon energies and chemical concentrations. The best sensitivity and photostability of the dosimeter were achieved with 2.5% wt. LMG and 8.2% wt. bromoform. Scanner used should not emit any UV radiation as it will expose the dosimeter, as with the Epson 10000 XL scanner

  3. Spectroscopic Dosimeter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Analysis of Phase I test data demonstrates that the Photogenics Spectroscopic Dosimeter will detect neutron energies from 0.8 up to 600 MeV. The detector...

  4. Hanford beta-gamma personnel dosimeter prototypes and evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Fix, J.J.; Holbrook, K.L.; Soldat, K.L.

    1983-04-01

    Upgraded and modified Hanford dosimeter prototypes were evaluated for possible use at Hanford as a primary beta-gamma dosimeter. All prototypes were compatible with the current dosimeter card and holder design, as well as processing with the automated Hanford readers. Shallow- and deep-dose response was determined for selected prototypes using several beta sources, K-fluorescent x rays and filtered x-ray techniques. All prototypes included a neutron sensitive chip. A progressive evaluation of the performance of each of the upgrades to the current dosimeter is described. In general, the performance of the current dosimeter can be upgraded using individual chip sensitivity factors to improve precision and an improved algorithm to minimize bias. The performance of this dosimeter would be adequate to pass all categories of the ANSI N13.11 performance criteria for dosimeter procesors, provided calibration techniques compatible with irradiations adopted in the standard were conducted. The existing neutron capability of the dosimeter could be retained. Better dosimeter performance to beta-gamma radiation can be achieved by modifying the Hanford dosimeter so that four of the five chip positions are devoted to calculating these doses instead of the currently used two chip positions. A neutron sensitive chip was used in the 5th chip position, but all modified dosimeter prototypes would be incapable of discriminating between thermal and epithermal neutrons. An improved low energy beta response can be achieved for the current dosimeter and all prototypes considered by eliminating the security credential. Further improvement can be obtained by incorporating the 15-mil thick TLD-700 chips.

  5. SU-E-T-643: Pure Alanine Dosimeter for Verification Dosimetry in IMRT

    Energy Technology Data Exchange (ETDEWEB)

    Al-Karmi, Anan M.; Zraiqat, Fadi [Physics Department, King Fahd University of Petroleum & Minerals, Dhahran 31261 (Saudi Arabia)

    2015-06-15

    Purpose: The objective of this study was evaluation of accuracy of pure alanine dosimeters measuring intensity-modulated radiation therapy (IMRT) dose distributions in a thorax phantom. Methods: Alanine dosimeters were prepared in the form of 110 mg pure L-α-alanine powder filled into clear tissue-equivalent polymethylmethacrylate (PMMA) plastic tubes with the dimensions 25 mm length, 3 mm inner diameter, and 1 mm wall thickness. A dose-response calibration curve was established for the alanine by placing the dosimeters at 1.5 cm depth in a 30×30×30 cm{sup 3} solid water phantom and then irradiating on a linac with 6 MV photon beam at 10×10 cm{sup 2} field size to doses ranging from 1 to 5 Gy. Electron paramagnetic resonance (EPR) spectroscopy was used to determine the absorbed dose in alanine. An IMRT treatment plan was designed for a commercial heterogeneous CIRS thorax phantom and the dose values were calculated at three different points located in tissue, lung, and bone equivalent materials. A set of dose measurements was carried out to compare measured and calculated dose values by placing the alanine dosimeters at those selected locations inside the thorax phantom and delivering the IMRT to the phantom. Results: The alanine dose measurements and the IMRT plan dose calculations were found to be in agreement within ±2%. Specifically, the deviations were −0.5%, 1.3%, and −1.7% for tissue, lung, and bone; respectively. The slightly large deviations observed for lung and bone may be attributed to tissue inhomogeneity, steep dose gradients in these regions, and uncontrollable changes in spectrometer conditions. Conclusion: The results described herein confirmed that pure alanine dosimeter was suitable for in-phantom dosimetry of IMRT beams because of its high sensitivity and acceptable accuracy. This makes the dosimeter a promising option for quality control of the therapeutic beams, complementing the commonly used ionization chambers, TLDs, and films.

  6. Enhancement of the optical properties of a new radiochromic dosimeter based on aliphatic-aromatic biodegradable polymers

    Energy Technology Data Exchange (ETDEWEB)

    Schimitberger, Thiago, E-mail: tschimitberger@ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Escola de Engenharia. Departamento de Engenharia Nuclear; Faria, Luiz O., E-mail: farialo@cdtn.br [Centro de desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-07-01

    The development of a dosimeter that is of low cost, easy to process without dependence on expensive complex instruments and environment friendly is a challenging in irradiation quality control. Recently, an aliphatic-aromatic biodegradable polymer has been proposed as radiochromic dosimeter. The dosimeter is based on biodegradable poly(butylene adipate-co-terephthalate) copolymers (PBAT). In order to improve the photoluminescence (PL) properties of PBAT, increasing its range of applicability (50 kGy to 1000 kGy), this work investigates the influence of solution concentration in the dose response. Films with thickness of c.a. 80 μm were produce by wirebar coating, a simple deposition method for preparing large areas of organic films at low cost. The irradiation of samples was performed at room temperature using a Co-60 source at dose rate of 20 kGy/h. The films were exposed to doses ranging from 501 kGy to 1000 kGy. A 405 nm LED light source was used to excite the films. The USB2000 spectrometer made by Ocean Optics was used to collect the emission spectra of the luminescent films. The photoluminescent intensity captured by the spectrometer present linear radiation dose dependence. The maximum PL for the film sample made from a 0.05 g.mL{sup -1} solution is 1.5 (a.u.) while it is about 3.5 (a.u.) for a film sample made from a 0.2 mg.mL{sup -1} solution, when irradiated with 1000 kGy. These results indicate that PBAT films have great potential to be used as a high gamma dose radiochromic dosimeter over a wide dose range, expanding its applicability for different radiations process. (author)

  7. Feasibility Study on Applying Radiophotoluminescent Glass Dosimeters for CyberKnife SRS Dose Verification.

    Science.gov (United States)

    Hsu, Shih-Ming; Hung, Chao-Hsiung; Liao, Yi-Jen; Fu, Hsiao-Mei; Tsai, Jo-Ting; Huang, Yung-Hui; Huang, David Y C

    2017-01-01

    CyberKnife is one of multiple modalities for stereotactic radiosurgery (SRS). Due to the nature of CyberKnife and the characteristics of SRS, dose evaluation of the CyberKnife procedure is critical. A radiophotoluminescent glass dosimeter was used to verify the dose accuracy for the CyberKnife procedure and validate a viable dose verification system for CyberKnife treatment. A radiophotoluminescent glass dosimeter, thermoluminescent dosimeter, and Kodak EDR2 film were used to measure the lateral dose profile and percent depth dose of CyberKnife. A Monte Carlo simulation for dose verification was performed using BEAMnrc to verify the measured results. This study also used a radiophotoluminescent glass dosimeter coupled with an anthropomorphic phantom to evaluate the accuracy of the dose given by CyberKnife. Measurements from the radiophotoluminescent glass dosimeter were compared with the results of a thermoluminescent dosimeter and EDR2 film, and the differences found were less than 5%. The radiophotoluminescent glass dosimeter has some advantages in terms of dose measurements over CyberKnife, such as repeatability, stability, and small effective size. These advantages make radiophotoluminescent glass dosimeters a potential candidate dosimeter for the CyberKnife procedure. This study concludes that radiophotoluminescent glass dosimeters are a promising and reliable dosimeter for CyberKnife dose verification with clinically acceptable accuracy within 5%.

  8. Evaluation of a Colorimetric Personal Dosimeter for Nitrogen Oxide.

    Science.gov (United States)

    Diamond, Philip

    A personal colorimetric dosimeter for nitrogen dioxide was developed. Tests were performed to determine the response of these strips to various concentrations of NO2. The dosimeter strips were satisfactory for approximate determinations of total exposure (concentration + time) of nitrogen dioxide. The total exposure was calculated in terms of time…

  9. Neutron Activation Foil and Thermoluminescent Dosimeter Responses to a Polyethylene Reflected Pulse of the CEA Valduc SILENE Critical Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Thomas Martin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Celik, Cihangir [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McMahan, Kimberly L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lee, Yi-kang [French Atomic Energy Commission (CEA), Saclay (France); Gagnier, Emmanuel [French Atomic Energy Commission (CEA), Centre de Saclay, Gif sur Yvette; Authier, Nicolas [French Atomic Energy Commission (CEA), Salives (France). Valduc Centre for Nuclear Studies; Piot, Jerome [French Atomic Energy Commission (CEA), Salives (France). Valduc Centre for Nuclear Studies; Jacquet, Xavier [French Atomic Energy Commission (CEA), Salives (France). Valduc Centre for Nuclear Studies; Rousseau, Guillaume [French Atomic Energy Commission (CEA), Salives (France). Valduc Centre for Nuclear Studies; Reynolds, Kevin H. [Y-12 National Security Complex, Oak Ridge, TN (United States)

    2016-09-01

    This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 19, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. The CIDAS detects gammas with a Geiger-Muller tube and the Rocky Flats detects neutrons via charged particles produced in a thin 6LiF disc depositing energy in a Si solid state detector. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

  10. Neutron Activation Foil and Thermoluminescent Dosimeter Responses to a Polyethylene Reflected Pulse of the CEA Valduc SILENE Critical Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Thomas Martin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Celik, Cihangir [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McMahan, Kimberly L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lee, Yi-kang [French Atomic Energy Commission (CEA), Saclay (France); Gagnier, Emmanuel [French Atomic Energy Commission (CEA), Centre de Saclay, Gif sur Yvette; Authier, Nicolas [French Atomic Energy Commission (CEA), Salives (France). Valduc Centre for Nuclear Studies; Piot, Jerome [French Atomic Energy Commission (CEA), Salives (France). Valduc Centre for Nuclear Studies; Jacquet, Xavier [French Atomic Energy Commission (CEA), Salives (France). Valduc Centre for Nuclear Studies; Rousseau, Guillaume [French Atomic Energy Commission (CEA), Salives (France). Valduc Centre for Nuclear Studies; Reynolds, Kevin H. [Y-12 National Security Complex, Oak Ridge, TN (United States)

    2016-09-01

    This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 19, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. The CIDAS detects gammas with a Geiger-Muller tube and the Rocky Flats detects neutrons via charged particles produced in a thin 6LiF disc depositing energy in a Si solid state detector. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

  11. Neutron Activation Foil and Thermoluminescent Dosimeter Responses to a Lead Reflected Pulse of the CEA Valduc SILENE Critical Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Thomas Martin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Celik, Cihangir [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Isbell, Kimberly McMahan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lee, Yi-kang [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Gagnier, Emmanuel [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Authier, Nicolas [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Piot, Jerome [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Jacquet, Xavier [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Rousseau, Guillaume [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Reynolds, Kevin H. [Y-12 National Security Complex, Oak Ridge, TN (United States)

    2016-09-01

    This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 13, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. The CIDAS detects gammas with a Geiger-Muller tube, and the Rocky Flats detects neutrons via charged particles produced in a thin 6LiF disc, depositing energy in a Si solid-state detector. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

  12. Linearization of dose-response curve of the radiochromic film dosimetry system

    Energy Technology Data Exchange (ETDEWEB)

    Devic, Slobodan; Tomic, Nada; Aldelaijan, Saad; DeBlois, Francois; Seuntjens, Jan; Chan, Maria F.; Lewis, Dave [Medical Physics Unit, McGill University, Montreal, Quebec H3G 1A4 (Canada) and Department of Radiation Oncology, SMBD Jewish General Hospital, McGill University, Montreal, Quebec H3T 1E2 (Canada); Executive Administration for Radiation Protection and Safety Medical Devices Sector, Saudi Food and Drug Authority, Riyadh, Kingdom of Saudi Arabia 13312 (Saudi Arabia); Medical Physics Unit, McGill University, Montreal, Quebec H3G 1A4 (Canada) and Department of Radiation Oncology, SMBD Jewish General Hospital, McGill University, Montreal, Quebec H3T 1E2 (Canada); Medical Physics Unit, McGill University, Montreal, Quebec H3G 1A4 (Canada); Department of Medical Physics, Memorial Sloan-Kettering Cancer Center Basking Ridge, New Jersey 07920 (United States); Ashland Inc., Wayne, New Jersey 07470 (United States)

    2012-08-15

    Purpose: Despite numerous advantages of radiochromic film dosimeter (high spatial resolution, near tissue equivalence, low energy dependence) to measure a relative dose distribution with film, one needs to first measure an absolute dose (following previously established reference dosimetry protocol) and then convert measured absolute dose values into relative doses. In this work, we present result of our efforts to obtain a functional form that would linearize the inherently nonlinear dose-response curve of the radiochromic film dosimetry system. Methods: Functional form [{zeta}= (-1){center_dot}netOD{sup (2/3)}/ln(netOD)] was derived from calibration curves of various previously established radiochromic film dosimetry systems. In order to test the invariance of the proposed functional form with respect to the film model used we tested it with three different GAFCHROMIC Trade-Mark-Sign film models (EBT, EBT2, and EBT3) irradiated to various doses and scanned on a same scanner. For one of the film models (EBT2), we tested the invariance of the functional form to the scanner model used by scanning irradiated film pieces with three different flatbed scanner models (Epson V700, 1680, and 10000XL). To test our hypothesis that the proposed functional argument linearizes the response of the radiochromic film dosimetry system, verification tests have been performed in clinical applications: percent depth dose measurements, IMRT quality assurance (QA), and brachytherapy QA. Results: Obtained R{sup 2} values indicate that the choice of the functional form of the new argument appropriately linearizes the dose response of the radiochromic film dosimetry system we used. The linear behavior was insensitive to both film model and flatbed scanner model used. Measured PDD values using the green channel response of the GAFCHROMIC Trade-Mark-Sign EBT3 film model are well within {+-}2% window of the local relative dose value when compared to the tabulated Cobalt-60 data. It was also

  13. Dielectric material for dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Moran, P.R.; Podgorsak, E.; Fullerton, G.D.; Fuller, G.E.

    1976-01-27

    A RITAD dosimeter is described having a dielectric material such as sapphire wherein the efficiency as measured by mean drift distance and trapping efficiency is increased by making use of a dielectric material in which the total active impurity does not exceed 50 ppm and in which any one active impurity does not exceed 10 ppm.

  14. Neutron Activation Foil and Thermoluminescent Dosimeter Responses to a Lead Reflected Pulse of the CEA Valduc SILENE Critical Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Thomas Martin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Celik, Cihangir [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Isbell, Kimberly McMahan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lee, Yi-kang [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Gagnier, Emmanuel [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Authier, Nicolas [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Piot, Jerome [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Jacquet, Xavier [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Rousseau, Guillaume [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Reynolds, Kevin H. [Y-12 National Security Complex, Oak Ridge, TN (United States)

    2016-09-01

    This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 13, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. The CIDAS detects gammas with a Geiger-Muller tube, and the Rocky Flats detects neutrons via charged particles produced in a thin 6LiF disc, depositing energy in a Si solid-state detector. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

  15. EDR-2 film response to charged particles.

    Science.gov (United States)

    Moyers, M F

    2008-05-21

    A useful tool for verifying segmental or dynamic treatments with multiple multi-leaf collimator positions, spinning range modulator propellors or magnetically scanned beams would be a film with a linear dose response up to several hundred centiGray, as typical for delivered treatments. Kodak has released an extended range film (EDR-2) that may satisfy this desire. In this study, dose response curves were obtained for several electron, proton, carbon ion and iron ion beams of different energies to determine the utility of this film.

  16. Basic radiological characteristics of a non-scattering gel dosimeter for 3D dosimetry

    Science.gov (United States)

    Chang, Kyung Hwan; Ji, Yunseo; Lee, Suk; Kim, Kwang Hyeon; Yang, Dae Sik; Lee, Jung Ae; Park, Young Je; Yoon, Won Sup; Kim, Chul Yong; Cao, Yuanjie; Cho, Samju

    2016-12-01

    We used a spectrophotometer to compare the dosimetric properties of two non-scattering (radiochromic) gel dosimeters: a non-scattering gel dosimeter developed in-house and a PRESAGE™ gel dosimeter. We evaluated the dosimetric characteristics, including spectral absorption, dose linearity, reproducibility, and dose rate dependency of the two gel dosimeters. The non-scattering gel and the PRESAGE™ gel dosimeters showed peak sensitivity at wavelengths of 600 nm and 630 nm, respectively. Over a range of doses the best dose linearities of the non-scattering and the PRESAGE™ gel dosimeters resulted in R2 values of 0.99 at wavelengths of 600 nm and 630 nm, respectively. The reproducibility and dose-rate dependence of each of the two gel dosimeters were within the range of ±3 %. Our results revealed that the peak sensitivities of the two radiochromic gel dosimeters were significantly different; the in-house non-scattering gel dosimeter demonstrated peak sensitivity at a wavelength of 600 nm while the PRESAGE™ gel dosimeter had peak sensitivity at a wavelength of 630 nm. We confirmed that for 3D gel dosimetry, the in-house non-scattering gel dosimeter had a more stable dose response compared with a commercial non-scattering gel dosimeter.

  17. Dosimeter Design Program

    Science.gov (United States)

    2015-01-05

    to measure the radiation at various altitudes and orbital inclinations. By understanding the actual levels, this allows developers of large (and...surface (200km – 400km) from many of the effects of solar radiation . This means that standard commercial electronics (which are much cheaper) can often...applied over each dosimeter to provide an indication of the energy spectrum of the space radiation . The instrument incorporates radiation hardened

  18. Radiochromic film containing methyl viologen for radiation dosimetry

    DEFF Research Database (Denmark)

    Lavalle, M.; Corda, U.; Fuochi, P.G.;

    2007-01-01

    , humidity and temperature on the response of the PVA-MV2+ dosimeter film have been studied under laboratory conditions. We conclude that the PVA film containing MV2+ is a promising tool for the absorbed dose measurements in several industrial applications of ionizing radiations. (C) 2007 Elsevier Ltd. All...

  19. SU-E-T-265: Presage Thin Sheet Dosimeter Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Dumas, M; Rakowski, J [Wayne State University/Karmanos Cancer Institute, Detroit, MI (United States)

    2014-06-01

    Purpose: To quantify the sensitivity and stability of the Presage dosimeter in sheet form for different concentrations of chemicals and for a diverse range of clinical photon energies. Methods: Presage polymer dosimeters are formulated to investigate and optimize their sensitivity and stability. The dosimeter is composed of clear polyurethane base, leucomalachite green reporting dye, and bromoform radical initiator in 1mm thick sheets. The chemicals are well mixed together, cast in an aluminum mold, and left to cure at 60 psi for a minimum of 2 days. Dosimeter response will be characterized at multiple energies including Co-60, 6 MV, 15 MV, 50 kVp, and 250 kVp. The dosimeters are read by an Epson 10000 XL scanner at 800 dpi, 2{sup 16} bit depth. Red component images are analyzed with ImageJ. Results: Analysis of optical density verse dose for Co-60 energies indicates that the bromoform containing Presage was able to quantify dose from 0 to 300 Gy, with saturation beyond 300 Gy. Initial results show two regions of linear response, 0–100 Gy and 150–300 Gy. The 150–300 Gy region has a sensitivity of 0.0024 net OD/Gy. Further results on other energies are still in progress. Conclusions: This work shows the potential for use of thin sheets of Presage dosimeter as a dosimeter capable of being analyzed with a flatbed scanner.

  20. Investigating the accuracy of microstereotactic-body-radiotherapy utilizing anatomically accurate 3D printed rodent-morphic dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Bache, Steven T.; Juang, Titania; Belley, Matthew D. [Duke University Medical Physics Graduate Program, Durham, North Carolina 27705 (United States); Koontz, Bridget F.; Yoshizumi, Terry T.; Kirsch, David G.; Oldham, Mark, E-mail: mark.oldham@duke.edu [Duke University Medical Center, Durham, North Carolina 27710 (United States); Adamovics, John [Rider University, Lawrenceville, New Jersey 08648 (United States)

    2015-02-15

    continuous arc at 225 kVp with a 20 × 10 mm field size. Dose response was evaluated using both the Presage/optical-CT 3D dosimetry system described above, and independent verification in select planes using EBT2 radiochromic film placed inside rodent-morphic dosimeters that had been sectioned in half. Results: Rodent-morphic 3D dosimeters were successfully produced from Presage radiochromic material by utilizing 3D printed molds of rat CT contours. The dosimeters were found to be compatible with optical-CT dose readout in high-resolution 3D (0.5 mm isotropic voxels) with minimal artifacts or noise. Cone-beam CT image guidance was possible with these dosimeters due to sufficient contrast between high-Z spinal inserts and tissue equivalent Presage material (CNR ∼10 on CBCT images). Dose at isocenter measured with optical-CT was found to agree with nanoscintillator measurement to within 2.8%. Maximum dose in line profiles taken through Presage and film dose slices agreed within 3%, with FWHM measurements through each profile found to agree within 2%. Conclusions: This work demonstrates the feasibility of using 3D printing technology to make anatomically accurate Presage rodent-morphic dosimeters incorporating spinal-mimicking inserts. High quality optical-CT 3D dosimetry is feasible on these dosimeters, despite the irregular surfaces and implanted inserts. The ability to measure dose distributions in anatomically accurate phantoms represents a powerful useful additional verification tool for preclinical microSBRT.

  1. Fast infrared response of YBCO thin films

    Science.gov (United States)

    Ballentine, P. H.; Kadin, A. M.; Donaldson, W. R.; Scofield, J. H.; Bajuk, L.

    1990-01-01

    The response to short infrared pulses of some epitaxial YBCO films prepared by sputter deposition and by electron-beam evaporation is reported. The response is found to be essentially bolometric on the ns timescale, with some indirect hints of nonequilibrium electron transport on the ps scale. Fast switching could be obtained either by biasing the switch close to the critical current or by cooling the film below about 20 K. These results are encouraging for potential application to a high-current optically-triggered opening switch.

  2. The annealing effect of radiochromic film dosimeter%辐射变色薄膜剂量计的退火效应

    Institute of Scientific and Technical Information of China (English)

    王硕; 陈家胜; 何捷; 孙鹏

    2013-01-01

    In this study, a batch of radiochromic films were prepared. The cdor of the film became blue after irradiating by low energy density of ultraviolet radiation using CL-1000UV cross-linking instrument. An absorption peak appeared at 670nm. The absorption peak absorbance has a good linear response relationship of radiation dose. The annealing experiments of the film were conducted after the irradiation. When the temperature was raised to 45 ℃ , a new absorption peak appeared at 545nm. Along with the further elevation of the temperature, 670nm peak gradually disappeared and 545nm peak rose gradually. When the temperature reached 110℃ , 670nm peak completely disappeared, 545nm peak was stabilized, and the color of the film was also correspondingly changed from blue to pink. The change of radiochromic film after irradiation could be expounded by infrared spectroscopy which showed that carbon-carbon triple bond conjugated (colorless) changed into a carbon-carbon triple bond and carbon-carbon double bond conjugate in different planes (blue) ,finally into the carbon-carbon triple bond and carbon-carbon double bond conjugate in a same plane (red).%制备了一批辐射变色薄膜,利用紫外线辐照该薄膜,辐照后薄膜由无色变为蓝色,并在670nm处出现一吸收峰,吸收峰的吸光度对辐照剂量有良好的线性响应关系.对辐照后的薄膜进行了退火实验,当温度升高到45℃后,出现一新的吸收峰(545nm),随着温度进一步升高670nm峰逐渐消失,545nm峰逐渐升高.当温度达到110℃时,670nm峰完全消失,545nm峰达到稳定,薄膜也相应地由蓝色变为粉红色.薄膜颜色的变化主要是由于其内部分子结构发生了变化:由碳碳三键共轭(无色)变为辐照后的碳碳三键和碳碳双键不在一个平面内的共轭(蓝),最后变为退火后的碳碳三键和碳碳双键在一个平面内的共轭(粉红).进一步的红外光谱分析也证实了对薄膜结构变化的解释.

  3. ESR dosimeter material properties of phenols compound exposed to radiotherapeutic electron beams

    Science.gov (United States)

    Gallo, Salvatore; Iacoviello, Giuseppina; Bartolotta, Antonio; Dondi, Daniele; Panzeca, Salvatore; Marrale, Maurizio

    2017-09-01

    There is a need for a sensitive dosimeter using Electron Spin Resonance spectroscopy for use in medical applications, since non-destructive read-out and dose archival could be achieved with this method. This work reports a systematic ESR investigation of IRGANOX ® 1076 exposed to clinical electron beams produced by a LINAC used for radiation therapy treatments. Recently, dosimetric features of this material were investigated for irradiation with 60Co γ -photons and neutrons in both pellet and film shape and have been found promising thanks to their high efficiency of radiation-matter energy transfer and radical stability at room temperature. Here the analysis of the dosimetric features of these ESR dosimeters exposed to clinical electron beams at energies of 7, 10 and 14 MeV, is described in terms of dependence on microwave power and modulation amplitude, response on dose, dependence on beam type, detection limits, and signal stability after irradiation. The analysis of the ESR signal as function of absorbed dose highlights that the response of this material is linear in the dose range investigated (1-13 Gy) and is independent of the beam energy. The minimum detectable dose is found to be smaller than 1 Gy. Comparison of electron stopping power values of these dosimeters with those of water and soft tissue highlights equivalence of the response to electron beams in the energy range considered. The signal intensity was monitored for 40 days after irradiation and for all energies considered and it shows negligible variations in the first 500 h after irradiation whereas after 1100 h the signal decay is only of about 4%. In conclusion, it is found that phenolic compounds possess good dosimetric features which make it useful as a sensitive dosimeter for medical applications.

  4. Theoretical and practical implications of the effects of temperature during irradiation and during pre- and post-irradiation storage on the response of thermoluminescence dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Gail de Planque, E.

    1984-01-01

    Experiments have been conducted to determine the applicability of the Randall-Wilkins theory for describing the behavior of CaF/sub 2/:Mn thermoluminescence dosimeters (Harshaw TLD-400 chips). Results were obtained for four different conditions: irradiation followed by storage, irradiation after storage, irradiation both preceded and followed by storage, and continuous simultaneous irradiation and storage. The experiments were performed for storage intervals of approximately 1, 2, 3, 5, 6 and 7 days at five different storage temperatures: -25, +20, +65, +150 and +175/sup 0/C. The results indicate fading that is described not by the Randall-Wilkins theory but rather as a linear function of the logarithm of the storage time. While the results suggest that the trapping efficiency is independent of temperature, they do demonstrate a small decrease in TL response with storage time prior to irradiation which is independent of temperature and time (>17 hours) and hence probably not dosimetric in origin but perhaps optically related. Glow curve analyses support the concept of a band of traps rather than a single trap. The overall results are compared to other data available in the literature most of which is for room-temperature storage. These data, for storage periods ranging from minutes to one year, can also be described as a linear function of the logarithm of the storage time and are remarkably consistent when uniformly normalized. Although peripheral experiments revealed problems associated with self-irradiation as well as a decline in sensitivity with use, the stability experiment results verify the highly favorable stability properties of CaF/sub 2/:Mn for widespread application.

  5. Positioning of personnel dosimeters - comments on replies

    Energy Technology Data Exchange (ETDEWEB)

    Field, R.W. (Academy of Health Sciences, U.S. Army, Fort Sam Houston, TX); Wiatrowski, W.A. (Audi L. Murphy Memorial Veterans Hospital, San Antonio, TX (USA)); Bushong, S.C. (Baylor Univ., Houston, TX (USA). Coll. of Medicine)

    1982-02-01

    Comments are made on a paper published in 1980 concerning the positioning of personnel dosimeters on individuals wearing protective aprons in diagnostic radiology. The main issue under discussion is whether an additional film badge should be worn on the collar to monitor head and neck exposure while wearing the lead apron over the whole body badge to avoid misinterpretations of reported 'whole body' exposure data. The recommendations on this issue are conflicting in NRCP Reports 57 and 59 and thus clarification is sought.

  6. Antioxidant effect of green tea on polymer gel dosimeter

    Science.gov (United States)

    Samuel, E. J. J.; Sathiyaraj, P.; Deena, T.; Kumar, D. S.

    2015-01-01

    Extract from Green Tea (GTE) acts as an antioxidant in acrylamide based polymer gel dosimeter. In this work, PAGAT gel was used for investigation of antioxidant effect of GTE.PAGAT was called PAGTEG (Polyacrylamide green tea extract gel dosimeter) after adding GTE. Free radicals in water cause pre polymerization of polymer gel before irradiation. Polyphenols from GTE are highly effective to absorb the free radicals in water. THPC is used as an antioxidant in polymer gel dosimeter but here we were replaced it by GTE and investigated its effect by spectrophotometer. GTE added PAGAT samples response was lower compared to THPC added sample. To increase the sensitivity of the PAGTEG, sugar was added. This study confirmed that THPC was a good antioxidant for polymer gel dosimeter. However, GTE also can be used as an antioxidant in polymer gel if use less quantity (GTE) and add sugar as sensitivity enhancer.

  7. Modified ferrous ammonium sulfate benzoic acid xyelenol orange (MFBX) and thermoluminescent dosimeters--a comparative study.

    Science.gov (United States)

    Brindha, S; Rose, J V R; Sathyan, S; Singh I, Rabi Raja; Ravindran, B Paul

    2002-06-07

    Radiation dosimetry deals with the determination of absorbed dose to the medium exposed to ionizing radiation. Chemical dosimetry depends on oxidation or reduction of chemicals by ionizing radiation. A ferrous ammonium sulfate benzoic acid xyelenol orange (FBX) dosimeter based on this principle is being used as a clinical dosimeter at present. Certain modifications were carried out in the preparation and storage of the FBX dosimeter to increase its shelf life. The resulting dosimeter was called a modified FBX (MFBX) dosimeter and has been used in our department for the past few years. An extensive study of the dose, dose rate and energy response of the dosimeter was carried out and compared with a thermoluminescent (LiF7) dosimeter. The results obtained were found to be comparable to the thermoluminescent (LiF7) dosimeter. Hence it was concluded that the MFBX dosimeter could be used for phantom dosimetry, data collection and in vivo measurements. Easier preparation and availability of the reagents are added advantages of using MFBX as a clinical dosimeter in small radiotherapy departments.

  8. Personnel Photon Dosimeter on the Base of TLD natLiF

    CERN Document Server

    Kaskanov, G Ya

    2003-01-01

    A personnel photon dosimeter on the base of thermoluminescence detectors (TLD) ^{nat}LiF is described. Experimental responses of the dosimeters in the unit of individual equivalent dose H_p(10) for energy of photons 59.5, 120, 662, and 1250 keV are presented. It is shown that the dosimeter allows one to measure H_p(10) with admissible uncertainty in the energy range from 60 to 1250 keV.

  9. Entrance surface dose measurements using a small OSL dosimeter with a computed tomography scanner having 320 rows of detectors.

    Science.gov (United States)

    Takegami, Kazuki; Hayashi, Hiroaki; Yamada, Kenji; Mihara, Yoshiki; Kimoto, Natsumi; Kanazawa, Yuki; Higashino, Kousaku; Yamashita, Kazuta; Hayashi, Fumio; Okazaki, Tohru; Hashizume, Takuya; Kobayashi, Ikuo

    2017-03-01

    Entrance surface dose (ESD) measurements are important in X-ray computed tomography (CT) for examination, but in clinical settings it is difficult to measure ESDs because of a lack of suitable dosimeters. We focus on the capability of a small optically stimulated luminescence (OSL) dosimeter. The aim of this study is to propose a practical method for using an OSL dosimeter to measure the ESD when performing a CT examination. The small OSL dosimeter has an outer width of 10 mm; it is assumed that a partial dose may be measured because the slice thickness and helical pitch can be set to various values. To verify our method, we used a CT scanner having 320 rows of detectors and checked the consistencies of the ESDs measured using OSL dosimeters by comparing them with those measured using Gafchromic™ films. The films were calibrated using an ionization chamber on the basis of half-value layer estimation. On the other hand, the OSL dosimeter was appropriately calibrated using a practical calibration curve previously proposed by our group. The ESDs measured using the OSL dosimeters were in good agreement with the reference ESDs from the Gafchromic™ films. Using these data, we also estimated the uncertainty of ESDs measured with small OSL dosimeters. We concluded that a small OSL dosimeter can be considered suitable for measuring the ESD with an uncertainty of 30 % during CT examinations in which pitch factors below 1.000 are applied.

  10. Dosimetric comparison on tissue interfaces with TLD dosimeters, L-alanine, EDR2 films and Penelope simulation for a Co-60 source and linear accelerator in radiotherapy; Comparacion dosimetrica en interfaces de tejidos con dosimetros TLD, L-alanina, peliculas EDR2 y simulacion Penelope para una fuente de Co-60 y acelerador lineal en radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Vega R, J. L.; Cayllahua, F.; Apaza, D. G.; Javier, H., E-mail: josevegaramirez@yahoo.es [Universidad Nacional de San Agustin, Departamento de Fisica, Av. Independencia s/n, Arequipa (Peru)

    2015-10-15

    Percentage depth dose curves were obtained with TLD-100 dosimeters, EDR2 films and Penelope simulation at the interfaces in an inhomogeneous mannequin, composed by equivalent materials to the human body built for this study, consisting of cylindrical plates of solid water-bone-lung-bone-solid water of 15 cm in diameter and 1 cm in height; plates were placed in descending way (4-2-8-2-4). Irradiated with Co-60 source (Theratron Equinox-100) for small radiation fields 3 x 3 cm{sup 2} and 1 x 1 cm{sup 2} at a surface source distance of 100 cm from mannequin. The TLD-100 dosimeters were placed in the center of each plate of mannequin irradiated at 10 Gy. The results were compared between these measurement techniques, giving good agreement in interfaces better than 97%. This study was compared with the same characteristics of another study realized with other equivalent materials to human body not homogeneous acrylic-bone-cork-bone-acrylic. The percentage depth dose curves were obtained with mini-dosimeters L-alanine of 1 mm in diameter and 3 mm in height and 3.5 to 4.0 mg of mass with spectrometer band K (EPR). The mini-dosimeters were irradiated with a lineal accelerator PRIMUS Siemens 6 MV. The results of percentage depth dose of L-alanine mini-dosimeters show a good agreement with the percentage depth dose curves of Penelope code, better than 97.7% in interfaces of tissues. (Author)

  11. Feasibility of Ultra-Thin Fiber-Optic Dosimeters for Radiotherapy Dosimetry

    Directory of Open Access Journals (Sweden)

    Bongsoo Lee

    2015-11-01

    Full Text Available In this study, prototype ultra-thin fiber-optic dosimeters were fabricated using organic scintillators, wavelength shifting fibers, and plastic optical fibers. The sensor probes of the ultra-thin fiber-optic dosimeters consisted of very thin organic scintillators with thicknesses of 100, 150 and 200 μm. These types of sensors cannot only be used to measure skin or surface doses but also provide depth dose measurements with high spatial resolution. With the ultra-thin fiber-optic dosimeters, surface doses for gamma rays generated from a Co-60 therapy machine were measured. Additionally, percentage depth doses in the build-up regions were obtained by using the ultra-thin fiber-optic dosimeters, and the results were compared with those of external beam therapy films and a conventional fiber-optic dosimeter.

  12. Miniature spectrally selective dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Adams, R.R.; Macconochie, I.O.; Poole, B.D.

    1983-02-08

    The present invention discloses a miniature spectrally selective dosimeter capable of measuring selected bandwidths of radiation exposure on small mobile areas. This is achieved by the combination of photovoltaic detectors, electrochemical integrators (e-cells) and filters in a small compact case which can be easily attached in close proximity to and substantially parallel to the surface being measured. In one embodiment two photovoltaic detectors, two e-cells and three filters are packaged in a small case with attaching means consisting of a safety pin. In another embodiment, two detectors, one e-cell and three filters are packaged in a small case with attaching means consisting of a clip to clip over a side piece of an eye glass frame in a further embodiment, the electro-optic elements a packaged in a wristwatch case with attaching means being a watchband. The filters in all embodiments allow only selected wavelengths of radiation to be detected by the photovoltaic detectors and then integrated by the e-cells.

  13. Experiences with electronic personal dosimeters at Dukovany Nuclear Power Plant-Czech Republic

    Energy Technology Data Exchange (ETDEWEB)

    Jurochova, Bozena; Zelenka, Zdenik [Personal Dosimetry Department NPP Dukovany (Czech Republic)

    2004-07-01

    The Dukovany Nuclear Power Plant operates four WWER-440 type reactors. Unit 1 has been operating since 1985, Unit 2 and Unit 3 since 1986, Unit 4 was connected to the grid in 1987. At Dukovany NPP occupational dosimetry is performed by approved Personal Dosimetry Service. The basic facilities for measuring external exposure are film badge (legal dosimeter), electronic personal dosimeter (EPD) and radio-photoluminescent dosimeter (RPL) as operational dosimeter, TLD for measuring doses to the extremities and TLD albedo dosimeter as neutron dosimeter. The presentation is based on the experiences with electronic personal dosimeters gathered at Dukovany NPP for the last three years. Electronic Personal Dosimetry System (EPDS) was developing by Czech company VF, a.s. and from 2002 year is also used at Temelin NPP (Czech Republic), SE VYZ Bohunice (Slovakia) and SE Mochovce NPP (Slovakia) as well. EPDS is designed for Merlin Gerin, Siemens and RADOS electronic dosimeters. Application SW for data analysis is used for daily monitoring of personal doses and for evaluation of collective doses during outages. System gives information about collective doses on devices and collective doses for select work tasks during outages. In addition EPDS allows the calculation of dose indexes I{sub D}. (I{sub D} is the ratio of the relevant collective dose and the number of equivalent working hours). This information is applicable for planning doses on special working activities for next outages and allows a detection radiation sources also.

  14. Clinical application of glass dosimeter for in vivo dose measurements of total body irradiation treatment technique

    Energy Technology Data Exchange (ETDEWEB)

    Rah, Jeong-Eun; Hwang, Ui-Jung; Jeong, Hojin; Lee, Sang-Yeob; Lee, Doo-Hyun; Shin, Dong Ho; Yoon, Myonggeun; Lee, Se Byeong [Proton Therapy Center, National Cancer Center, 809 Madu-dong, Ilsan-gu, Goyang-si, Gyeonggi-do, 410-769 (Korea, Republic of); Lee, Rena [Department of Radiation Oncology, Mokdong Hospital, Ewha Womans University College of Medicine (Korea, Republic of); Park, Sung Yong, E-mail: cool_park@ncc.re.k [Proton Therapy Center, National Cancer Center, 809 Madu-dong, Ilsan-gu, Goyang-si, Gyeonggi-do, 410-769 (Korea, Republic of)

    2011-01-15

    The commercially available glass dosimeter (model GD-301) was investigated for its dosimetric characteristics, in order to evaluate its use for in vivo dosimetry. We specifically assessed overall precision of dosimetric dose data in patients who received treatment with the total body irradiation (TBI). Uniformity obtained in this study was within 1.2% (1 SD). The dose-response was linear in the range of 0.5-10 Gy with R of 0.999. Dose rate, SSD, field size, angular and energy dependence were found to be within 3.0%. In vivo skin dosimetry for TBI was performed for 3 patients. For all patients, the glass dosimeter was exposed and measured dose recorded for one fraction in addition to conventional used TLD and MOSFET. Overall uncertainty of the glass dosimeter for in vivo dose measurement was estimated at 2.4% (68.3% confidence level). The measured doses of the glass dosimeter were well within {+-}5.0% of the prescription dose at all sites expect mediastinum of one patient, for which it is within {+-}5.7%. Agreement of measured doses between glass dosimeter and TLD, MOSFET was within {+-}6.3% and {+-}6.6%, respectively. Results show that the glass dosimeter can be used as an accurate and reproducible dosimeter for TBI treatment skin dose measurements. The glass dosimeter is a practical alternative to TLD or MOSFET as an in vivo dosimeter.

  15. To the attention of all dosimeter users

    CERN Multimedia

    2005-01-01

    Many regular users of CERN personal dosimeters do not respect the safety regulations, which include the compulsory monthly read-out of the dosimeter. Therefore we would like to remind everybody that if the dosimeter is not read for a period of 3 months or more, we will ask for a return or replacement of the dosimeter, which has a value of CHF 350.-. We would like to emphasise that the dosimeter must be read even if you have not entered controlled areas. Staff members or CERN users who enter controlled areas only occasionally may exchange their regular dosimeter for a short term visitor dosimeter (VCT). This dosimeter has a limited validity period but without for a compulsory periodic read-out. For further information please contact dosimetry.service@cern.ch Thank you for your cooperation. Dosimetry Service Bld 24 E 011 http://cern.ch/rp-dosimetry

  16. To the attention of all dosimeter users

    CERN Multimedia

    Dosimetry Service

    2006-01-01

    Many regular users of CERN personal dosimeters do not respect the safety regulations, which include the compulsory monthly read-out of the dosimeter. We would therefore like to remind everybody that if the dosimeter is not read for a period of 3 months or more, we will ask for a return or replacement of the dosimeter, which has a value of CHF 350,-. We would like to emphasise that the dosimeter must be read even if you have not entered controlled areas. Staff members or CERN users who enter controlled areas only occasionally may exchange their regular dosimeter for a short-term visitor dosimeter (VCT). This dosimeter has a limited validity period but does not require a periodic read-out. For further information please contact dosimetry.service@cern.ch Thank you for your cooperation. Dosimetry Service - Bldg. 24 E 011 - http://cern.ch/rp-dosimetry

  17. To the attention of all dosimeter users

    CERN Multimedia

    2005-01-01

    Many regular users of CERN personal dosimeters do not respect the safety regulations, which include a compulsory monthly read-out of the dosimeter. Therefore we would like to remind everybody that if the dosimeter is not read for a period of 3 months or more, we will ask for a return or replacement of the dosimeter, which has a value of CHF 350.-. We would like to emphasise that the dosimeter must be read even if you have not entered controlled areas. Staff members or CERN users who enter controlled areas only occasionally may exchange their regular dosimeter for a short term visitor dosimeter (VCT). This dosimeter has a limited validity period but without for a compulsory periodic read-out. For further information please contact dosimetry.service@cern.ch Thank you for your cooperation. Dosimetry Service Bldg. 24 E 011 http://cern.ch/rp-dosimetry

  18. Reproducibility Experiment of OSL and TL Dosimeter

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Reproducibility is an important property of personal dosimeter. It not only can indicate the stability of dosimeter, appraise the precision and accuracy of measured value, but also can evaluate the

  19. TSC response of irradiated CVD diamond films

    CERN Document Server

    Borchi, E; Bucciolini, M; Guasti, A; Mazzocchi, S; Pirollo, S; Sciortino, S

    1999-01-01

    CVD diamond films have been irradiated with electrons, sup 6 sup 0 Co photons and protons in order to study the dose response to exposure to different particles and energies and to investigate linearity with dose. The Thermally Stimulated Current (TSC) has been studied as a function of the dose delivered to polymethilmetacrilate (PMMA) in the range from 1 to 12 Gy with 20 MeV electrons from a linear accelerator. The TSC spectrum has revealed the presence of two components with peak temperatures of about 470 and 520 K, corresponding to levels lying in the diamond band gap with activation energies of the order of 0.7 - 1 eV. After the subtraction of the exponential background the charge emitted during the heating scan has been evaluated and has been found to depend linearly on the dose. The thermally emitted charge of the CVD diamond films has also been studied using different particles. The samples have been irradiated with the same PMMA dose of about 2 Gy with 6 and 20 MeV electrons from a Linac, sup 6 sup 0 ...

  20. Responsive copolymer films obtained by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Burillo, G.; Bucio, E. [Departamento de Quimica de Radiaciones y Radioquimica, Instituto de Ciencias Nucleares, UNAM, Circuito Exterior, Ciudad Universitaria, Mexico 04510, D. F. (Mexico)], e-mail: burillo@nucleares.unam.mx

    2009-07-01

    The graft copolymerization of ph and/or thermo sensitive monomers onto polymeric films can be achieved by different radiation methods which have great advantages compared to conventional methods. Their ph and thermal sensitivity properties, as well as LCST and critical ph point, have been studied by DSC, UV, FTIR, water contact angle and swelling. Graft copolymerization can be carried out by pre-irradiation oxidative and direct methods, using {sup 6}0Co gamma radiation or a Van de Graaff electron beam accelerator. The influence of synthesis conditions, such as pre-irradiation or radiation doses, dose rate, reaction time, monomer concentration, and reaction temperature are being studied. Advances in the field of responsive polymeric systems synthesized by ionizing radiation, their applications and promising future research on radiation graft polymerization and crosslinking will be discussed. (Author)

  1. Type testing of the SDM2000 personal dosimeter

    CERN Document Server

    LiuZhengShan; Deng Chang Ming; Guo Zhan Jie; Zhang Zhi Yong

    2001-01-01

    The results of the performance of a new type of personal dosimeter, the SDM2000 Personal Dosimeter made by China Institute for Radiation Protection is presented. Tests were performed on radiological performance including radiation energy, incidence angular, beta radiation, neutron radiation, accuracy of alarm levels, relative intrinsic error, overload, response time, linearity, retention of reading. There are also tests on the effects of a variety of environmental factors, such as temperature, humidity, external magnetic fields, electrostatic discharge, external electromagnetic fields. Other characteristics tested were dropping test, vibration test and battery life. The test results were compared with the relevant requirements of three standards: CIRP standard: Q/DSC1-92, National standard: GB/T 13161-91, IEC standard: IEC1283. In general, the performance of the SDM2000 personal dosimeter was found to be quite acceptable; it meets most of the relevant requirements of the three standards

  2. Neuroticism modifies psychophysiological responses to fearful films.

    Directory of Open Access Journals (Sweden)

    Emmanuelle Reynaud

    Full Text Available BACKGROUND: Neuroticism is a personality component frequently found in anxious and depressive psychiatric disorders. The influence of neuroticism on negative emotions could be due to its action on stimuli related to fear and sadness, but this remains debated. Our goal was thus to better understand the impact of neuroticism through verbal and physiological assessment in response to stimuli inducing fear and sadness as compared to another negative emotion (disgust. METHODS: Fifteen low neurotic and 18 high neurotic subjects were assessed on an emotional attending task by using film excerpts inducing fear, disgust, and sadness. We recorded skin conductance response (SCR and corrugator muscle activity (frowning as indices of emotional expression. RESULTS: SCR was larger in high neurotic subjects than in low neurotics for fear relative to sadness and disgust. Moreover, corrugator activity and SCR were larger in high than in low neurotic subjects when fear was induced. CONCLUSION: After decades of evidence that individuals higher in neuroticism experience more intense emotional reactions to even minor stressors, our results indicate that they show greater SCR and expressive reactivity specifically to stimuli evoking fear rather than to those inducing sadness or disgust. Fear processing seems mainly under the influence of neuroticism. This modulation of autonomic activity by neurotics in response to threat/fear may explain their increased vulnerability to anxious psychopathologies such as PTSD (post traumatic stress disorder.

  3. Radiochromic film containing methyl viologen for radiation dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Lavalle, M. [ISOF-CNR, Via P. Gobetti 101, 40129 Bologna (Italy)]. E-mail: lavalle@isof.cnr.it; Corda, U. [ISOF-CNR, Via P. Gobetti 101, 40129 Bologna (Italy); Fuochi, P.G. [ISOF-CNR, Via P. Gobetti 101, 40129 Bologna (Italy); Caminati, S. [ISOF-CNR, Via P. Gobetti 101, 40129 Bologna (Italy); Venturi, M. [Dipartimento di Chimica ' G. Ciamician' , Universita di Bologna, Via Selmi 2, 40126 Bologna (Italy); Kovacs, A. [Institute of Isotopes, HAS, P.O. Box 77, 1525 Budapest (Hungary); Baranyai, M. [Institute of Isotopes, HAS, P.O. Box 77, 1525 Budapest (Hungary); Safrany, A. [Institute of Isotopes, HAS, P.O. Box 77, 1525 Budapest (Hungary); Miller, A. [High Dose Reference Laboratory, Riso National Laboratory, DK-4000, Roskilde (Denmark)

    2007-08-15

    Poly(vinyl alcohol) (PVA) films containing methyl viologen (MV{sup 2+}) that colours blue upon exposure to ionizing radiation were investigated as possible dosimeters for use in radiation processing applications. In order to find the most suitable composition of the PVA-MV{sup 2+} film, different concentrations of the dye have been studied. The absorbance values at selected wavelengths, obtained from irradiation of the PVA film containing the most suitable MV{sup 2+} concentration, can be satisfactorily related to the absorbed dose over a wide range, from 50 Gy up to 40 kGy. The effects of dose, dose rate, humidity and temperature on the response of the PVA-MV{sup 2+} dosimeter film have been studied under laboratory conditions. We conclude that the PVA film containing MV{sup 2+} is a promising tool for the absorbed dose measurements in several industrial applications of ionizing radiations.

  4. Worlds of Possibilities in Response to Literature, Film, and Life.

    Science.gov (United States)

    Cox, Carole; Many, Joyce E.

    1989-01-01

    Examines the interrelationships between cinematic and literary works in terms of possible responses, or the possible worlds created when children encounter and create literary discourse. Notes that these responses reflect previous encounters with literature, film, and life. (MM)

  5. An assessment of radiotherapy dosimeters based on CVD grown diamond

    CERN Document Server

    Ramkumar, S; Conway, J; Whitehead, A J; Sussman, R S; Hill, G; Walker, S

    2001-01-01

    Diamond is potentially a very suitable material for use as a dosimeter for radiotherapy. Its radiation hardness, the near tissue equivalence and chemical inertness are some of the characteristics of diamond, which make it well suited for its application as a dosimeter. Recent advances in the synthesis of diamond by chemical vapour deposition (CVD) technology have resulted in the improvement in the quality of material and increased its suitability for radiotherapy applications. We report in this paper, the response of prototype dosimeters based on two different types (CVD1 and CVD2) of CVD diamond to X-rays. The diamond devices were assessed for sensitivity, dependence of response on dose and dose rate, and compared with a Scanditronix silicon photon diode and a PTW natural diamond dosimeter. The diamond devices of CVD1 type showed an initial increase in response with dose, which saturates after approx 6 Gy. The diamond devices of CVD2 type had a response at low fields (1162.8 V/cm), the CVD2-type devices show...

  6. Review of the dose-to-water energy dependence of alanine and lithium formate EPR dosimeters and LiF TL-dosimeters - Comparison with Monte Carlo simulations

    Energy Technology Data Exchange (ETDEWEB)

    Waldeland, Einar, E-mail: einar.waldeland@oslo-universitetssykehus.no [Department of Medical Physics, Oslo University Hospital, Norwegian Radium Hospital, P.O. Box 4953 Nydalen, N-0424 Oslo (Norway); Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Malinen, Eirik [Department of Medical Physics, Oslo University Hospital, The Norwegian Radium Hospital, P.O. Box 4953 Nydalen, N-0424 Oslo (Norway); Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway)

    2011-09-15

    The dose-to-water energy dependence may be defined as the dosimeter reading per absorbed dose to water for a given radiation beam relative to that for {sup 60}Co {gamma} rays. The purpose of this work was to review the literature on the dose-to-water energy dependence of lithium formate and alanine EPR dosimeters and LiF:Mg,Ti TL-dosimeters for clinical beam qualities and to compare the findings with Monte Carlo simulations. Monte Carlo simulations of the energy dependence of lithium formate and alanine EPR dosimeters and LiF:Mg,Ti TL-dosimeters were performed using the EGSnrc code. The following common clinical radiation qualities were applied: 4-24 MV photons, 4-20 MeV electrons, 50-200 kV{sub p} X-rays, {sup 192}Ir {gamma} rays, and {sup 60}Co {gamma} rays as the reference. All dosimeter materials showed measured and Monte Carlo simulated energy responses around unity for MV photons, electrons and {sup 192}Ir {gamma} rays, except LiF TL-dosimeters which showed an average underresponse of approximately 3% for electrons. For medium energy X-rays (50-200 kV{sub p}), LiF displayed an increasing overresponse with decreasing energy to a maximum of about 40% for 50 kV{sub p} X-rays. The two EPR dosimeter materials showed decreasing energy response with decreasing X-ray energy, but lithium formate was less dependent on energy than alanine. Comparisons between Monte Carlo simulations and measurements revealed some deviations for medium energy X-rays, which may be due to LET-effects caused by low energy electrons. In conclusion, lithium formate is the dosimeter material with the lowest energy dependence over a wide range of clinically relevant radiation qualities, which clearly is advantageous for accurate dosimetry.

  7. Psychophysiological response patterns to affective film stimuli.

    Directory of Open Access Journals (Sweden)

    Marieke G N Bos

    Full Text Available Psychophysiological research on emotion utilizes various physiological response measures to index activation of the defense system. Here we tested 1 whether acoustic startle reflex (ASR, skin conductance response (SCR and heart rate (HR elicited by highly arousing stimuli specifically reflect a defensive state and 2 the relation between resting heart rate variability (HRV and affective responding. In a within-subject design, participants viewed film clips with a positive, negative and neutral content. In contrast to SCR and HR, we show that ASR differentiated between negative, neutral and positive states and can therefore be considered as a reliable index of activation of the defense system. Furthermore, resting HRV was associated with affect-modulated characteristics of ASR, but not with SCR or HR. Interestingly, individuals with low-HRV showed less differentiation in ASR between affective states. We discuss the important value of ASR in psychophysiological research on emotion and speculate on HRV as a potential biological marker for demarcating adaptive from maladaptive responding.

  8. Dosimetry characterization of nitro-blue tetrazolium polyvinyl butyral films for radiation processing

    Science.gov (United States)

    Basfar, Ahmed A.; Rabaeh, Khalid A.; Moussa, Akram A.; Msalam, Rashed I.

    2011-06-01

    Nitro-blue tetrazolium polyvinyl butyral film dosimeters (NBT-PVB) were prepared and investigated based on radiation-induced reduction of NBT 2+. NBT-PVB film dosimeters containing different concentrations of NBT dye from 1 to 5 mM were prepared in a solution of ethanol. The dosimeters were irradiated with γ-ray from 60Co source at doses from 5 up to 55 kGy. UV/vis spectrophotometry was used to investigate the optical density of unirradiated and irradiated films in terms of absorbance at 529 nm. The absorbance increases with absorbed dose up to 55 kGy for NBT-PVB film dosimeters. The dose sensitivity of NBT-PVB film increases strongly with an increase in concentrations of NBT dye. The effects of irradiation temperature, humidity, dose rate and the stability of the response of the films after irradiation were investigated. The influence of irradiation temperature and humidity on the performance of the film was reduced significantly due to the use of PVB as a binder containing NBT dye.

  9. Dosimetry characterization of nitro-blue tetrazolium polyvinyl butyral films for radiation processing

    Energy Technology Data Exchange (ETDEWEB)

    Basfar, Ahmed A., E-mail: abasfar@kacst.edu.s [Radiation Technology Center, Atomic Energy Research Institute, King Abdulaziz City for Science and Technology, Riyadh (Saudi Arabia); Rabaeh, Khalid A. [Radiation Technology Center, Atomic Energy Research Institute, King Abdulaziz City for Science and Technology, Riyadh (Saudi Arabia); Radiography Department, Faculty of Allied Health Sciences, Hashemite University, Zarqa (Jordan); Moussa, Akram A. [Biomedical Physics Department, Research Center, King Faisal Specialist Hospital and Research Center, Riyadh (Saudi Arabia); Msalam, Rashed I. [Radiation Technology Center, Atomic Energy Research Institute, King Abdulaziz City for Science and Technology, Riyadh (Saudi Arabia)

    2011-06-15

    Nitro-blue tetrazolium polyvinyl butyral film dosimeters (NBT-PVB) were prepared and investigated based on radiation-induced reduction of NBT{sup 2+}. NBT-PVB film dosimeters containing different concentrations of NBT dye from 1 to 5 mM were prepared in a solution of ethanol. The dosimeters were irradiated with {gamma}-ray from {sup 60}Co source at doses from 5 up to 55 kGy. UV/vis spectrophotometry was used to investigate the optical density of unirradiated and irradiated films in terms of absorbance at 529 nm. The absorbance increases with absorbed dose up to 55 kGy for NBT-PVB film dosimeters. The dose sensitivity of NBT-PVB film increases strongly with an increase in concentrations of NBT dye. The effects of irradiation temperature, humidity, dose rate and the stability of the response of the films after irradiation were investigated. The influence of irradiation temperature and humidity on the performance of the film was reduced significantly due to the use of PVB as a binder containing NBT dye.

  10. Improved Response of ZnO Films for Pyroelectric Devices

    Directory of Open Access Journals (Sweden)

    Shih-Yuan Yu

    2012-12-01

    Full Text Available Increasing the temperature variation rate is a useful method for enhancing the response of pyroelectric devices. A three-dimensional ZnO film was fabricated by the aerosol deposition (AD rapid process using the shadow mask method, which induces lateral temperature gradients on the sidewalls of the responsive element, thereby increasing the temperature variation rate. To enhance the quality of the film and reduce the concentration of defects, the film was further treated by laser annealing, and the integration of a comb-like top electrode enhanced the voltage response and reduced the response time of the resulting ZnO pyroelectric devices.

  11. Improvements in opti-chromic dosimeters for radiation processing

    Science.gov (United States)

    Humpherys, K. C.; Kantz, A. D.

    "Opti-Chromic" dosimeters consisting of radiachromic dye in flourinated polymer tubing have been introduced as a dosimetry system in the range from 10 1 to 5 × 10 4 Gy. Batches of "Opti-Chromic" dosimeters have been produced to evaluate performance under large scale industrial conditions. A systematic study was undertaken to determine the effect of various dosimeter parameters on radiation sensitivity, shelf life, and response characteristics at the higher absorbed doses. These parameters were (A) Type of flourinated polymer tubing; (B) Organic solvent used to activate the radiachromic dye; (C) Concentration of radiachromic dye; (D) Additives to provide proper viscosity, color stability, and high-dose response. Prototype batches were produced and experimental dosimeters exposed to a range of absorbed doses and the response measured as a function of shelf life and dose. The results of the study are presented, and an improved formulation recommended for application to Food Processing. Other formulations may be of value in specific requirements of sensitivity or temperature.

  12. Development of colored alumilite dosimeter

    CERN Document Server

    Obara, K; Yagi, T; Yokoo, N

    2003-01-01

    In the ITER (International Thermonuclear Experimental Reactor), in-vessel components such as blanket and divertor, which are installed in the vacuum vessel of the ITER, are maintained by remote handling equipment (RH equipment). The RH equipment for maintenance is operated under sever environmental conditions, such as high temperature (50 approx 100 degC), high gamma-ray radiation (approx 1 kGy/h) in an atmosphere of inert gas or vacuum; therefore many components of the RH equipment must have a suitable radiation resistance efficiency for long time operation (10 approx 100 MGy). Typical components of the RH equipment have been extensively tested under an intensive gamma-ray radiation. Monitoring of the radiation dose of the components of the RH equipment is essential to control the operation period of the RH equipment considering radiation resistance. However, the maximum measurable radiation dose of the conventional dosimeters, such as ionization chamber, liquid, glass and plastic dosimeters are limited to b...

  13. Applications of Neutron Bubble Dosimeters for Neutron Dose Monitoring in Mixed n-γ Fields

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Bubble dosimeter is a promising technology in the field of neutron dosimetry. It provides real-time monitoring of neutron dose, stable energy response over wide range of neutron energy, and a very low

  14. VALIDATION OF HANFORD PERSONNEL AND EXTREMITY DOSIMETERS IN PLUTONIUM ENVIRONMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Scherpelz, Robert I.; Fix, John J.; Rathbone, Bruce A.

    2000-02-10

    A study was performed in the Plutonium Finishing Plant to assess the performance of Hanford personnel neutron dosimetry. The study was assessed whole body dosimetry and extremity dosimetry performance. For both parts of the study, the TEPC was used as the principle instrument for characterizing workplace neutron fields. In the whole body study, 12.7-cm-diameter TEPCs were used in ten different locations in the facility. TLD and TED personnel dosimeters were exposed on a water-filled phantom to enable a comparison of TEPC and dosimeter response. In the extremity study, 1.27-cm-diameter TEPCs were exposed inside the fingers of a gloveboxe glove. Extremity dosimeters were wrapped around the TEPCs. The glove was then exposed to six different cans of plutonium, simulating the exposure that a worker's fingers would receive in a glovebox. The comparison of TEPC-measured neutron dose equivalent to TLD-measured gamma dose equivalent provided neutron-to-gamma ratios that can be used to estimate the neutron dose equivalent received by a worker's finger based on the gamma readings of an extremity dosimeter. The study also utilized a Snoopy and detectors based on bubble technology for assessing neutron exposures, providing a comparison of the effectiveness of these instruments for workplace monitoring. The study concludes that the TLD component of the HCND performs adequately overall, with a positive bias of 30%, but exhibits excessive variability in individual results due to instabilities in the algorithm. The TED response was less variable but only 20% of the TEPC reference dose on average because of the low neutron energies involved. The neutron response of the HSD was more variable than the TLD component of the HCND and biased high by a factor of 8 overall due to its calibration to unmoderated 252Cf. The study recommends further work to correct instabilities in the HCND algorithm and to explore the potential shown by the bubble-based dosimeters.

  15. Feasibility study of a lead monoxide-based dosimeter for quality assurance in radiotherapy

    Science.gov (United States)

    Kim, K. T.; Han, M. J.; Heo, Y. J.; Park, J. E.; Lee, Y. K.; Kim, J. N.; Oh, K. M.; Cho, H. L.; Choi, Y. S.; Kim, J. Y.; Nam, S. H.; Park, S. K.

    2016-11-01

    Lately, cancer has been treated using high-energy radiation, and this requires highly reliable treatment plans. Therefore, a dosimeter with excellent performance, which is capable of precise dose measurement, is critical. In current clinical practices, an ionization chamber and diode utilizing the ionization reaction mechanism are widely used. Several studies have been carried out to determine optimal materials for the detector in a dosimeter to enable diagnostic imaging. Recently, studies with lead monoxide, which was shown to have low drift current and high resolving power at a high bias, were reported with the dosimeter exhibiting a fast response time against incident photons. This research aims to investigate the feasibility of a lead monoxide-based dosimeter for QA (quality assurance) in radiotherapy. In this paper, we report that the manufactured dosimeter shows similar linearity to a silicon diode and demonstrates similar characteristics in terms of PDD (percent depth dose) results for the thimble ionization chamber. Based on these results, it is demonstrated that the lead monoxide-based dosimeter complies with radiotherapy QA requirements, namely rapid response time, dose linearity, dose rate independence. Thus, we expect the lead monoxide-based dosimeter to be used commercially in the future.

  16. Dosimeter placement in the Rando phantom

    Energy Technology Data Exchange (ETDEWEB)

    Archer, B.R.; Glaze, S.; North, L.B.; Bushong, S.C.

    1977-07-01

    Each section of the Alderson Rando phantom contains a tissue-equivalent plastic coating layer approximately 2 mm thick, applied to both faces. This compensates for material removed in the sawing process. Conventional use of thermoluminescent dosimeters positions them totally or partially within the coating layer. Analysis shows that, in the lung region, dosimeters placed in this layer received a dose averaging 39% lower than those placed at midsection. Where bony structures interfere, some dosimeters in the coating layer received an 18% higher dose than those at midsection. Therefore, positioning dosimeters at the center of a section is recommended.

  17. Modeling, simulation and measurement of radiation exposure using electronic personal dosimeters on realistic and ICRU phantoms

    CERN Document Server

    Fuelle, D

    2003-01-01

    Exposure studies with voxel phantoms were carried out to understand the new personal dose measurand Hp(10) measured by personal dosimeters under realistic wearing conditions. Two simulated realistic voxel phantoms and the dosimeter assembly are described in a first step. Conditions such as photon fluence, radiation field geometry, and photon energy for simulating the external photon fields at the realistic model are specified. Person-related effective doses are calculated to evaluate the personal dose. The relation between measured deep personal dose and effective dose is demonstrated and discussed by means of the simulated response function of the dosimeters at realistic phantoms.

  18. Chemically tuned linear energy transfer dependent quenching in a deformable, radiochromic 3D dosimeter

    DEFF Research Database (Denmark)

    Høye, Ellen Marie; Skyt, Peter Sandegaard; Balling, Peter

    2017-01-01

    the observed quenching in proton beams. The dependency of dose response on linear energy transfer, as calculated through Monte Carlo simulations of the dosimeter, was investigated in 60 MeV proton beams. We found that the amount of quenching varied with the chemical composition: peak-to-plateau ratios (1cm...... chemical compositions of the dosimeter showed dose-rate dependency; however this was not dependent on the linear energy transfer. Track-structure theory was used to explain the observed quenching effects. In conclusion, this study shows that the silicone-based dosimeter has potential for use in measuring 3...

  19. EDR-2 (registered) film response to charged particles

    Energy Technology Data Exchange (ETDEWEB)

    Moyers, M F [Department of Radiation Medicine, Loma Linda University Medical Center, Loma Linda, CA 92354 (United States)], E-mail: MFMoyers@roadrunner.com

    2008-05-21

    A useful tool for verifying segmental or dynamic treatments with multiple multi-leaf collimator positions, spinning range modulator propellors or magnetically scanned beams would be a film with a linear dose response up to several hundred centiGray, as typical for delivered treatments. Kodak has released an extended range film (EDR-2) that may satisfy this desire. In this study, dose response curves were obtained for several electron, proton, carbon ion and iron ion beams of different energies to determine the utility of this film. (note)

  20. Optical and Nonlinear Optical Response of Light Sensor Thin Films

    Directory of Open Access Journals (Sweden)

    S. Z. Weisz

    2005-04-01

    Full Text Available For potential ultrafast optical sensor application, both VO2 thin films andnanocomposite crystal-Si enriched SiO2 thin films grown on fused quartz substrates weresuccessfully prepared using pulsed laser deposition (PLD and RF co-sputteringtechniques. In photoluminescence (PL measurement c-Si/SiO2 film containsnanoparticles of crystal Si exhibits strong red emission with the band maximum rangingfrom 580 to 750 nm. With ultrashort pulsed laser excitation all films show extremelyintense and ultrafast nonlinear optical (NLO response. The recorded holography fromall these thin films in a degenerate-four-wave-mixing configuration shows extremelylarge third-order response. For VO2 thin films, an optically induced semiconductor-tometalphase transition (PT immediately occurred upon laser excitation. it accompanied.It turns out that the fast excited state dynamics was responsible to the induced PT. For c-Si/SiO2 film, its NLO response comes from the contribution of charge carriers created bylaser excitation in conduction band of the c-Si nanoparticles. It was verified byintroducing Eu3+ which is often used as a probe sensing the environment variations. Itturns out that the entire excited state dynamical process associated with the creation,movement and trapping of the charge carriers has a characteristic 500 ps duration.

  1. Characterization of metal oxide semiconductor field effect transistor dosimeters for application in clinical mammography.

    Science.gov (United States)

    Benevides, Luis A; Hintenlang, David E

    2006-02-01

    Five high-sensitivity metal oxide semiconductor field effect transistor dosimeters in the TN-502 and 1002 series (Thomson Nielsen Electronics Ltd., 25B, Northside Road, Ottawa, ON K2H8S1, Canada) were evaluated for use in the mammography x-ray energy range (22-50 kVp) as a tool to assist in the documentation of patient specific average glandular dose. The dosimeters were interfaced with the Patient Dose Verification System, model No. TN-RD 15, which consisted of a dosimeter reader and up to four dual bias power supplies. Two different dual bias power supplies were evaluated in this study, model No. TN-RD 22 in high-sensitivity mode and a very-high sensitivity prototype. Each bias supply accommodates up to five dosimeters for 20 dosimeters per system. Sensitivity of detectors, defined as the mV/C kg(-1), was measured free in air with the bubble side of the dosimeter facing the x-ray field with a constant exposure. All dosimeter models' angular response showed a marked decrease in response when oriented between 120 degrees and 150 degrees and between at 190 degrees and 220 degrees relative to the incident beam. Sensitivity was evaluated for Mo/Mo, Mo/Rh, and Rh/Rh target-filter combinations. The individual dosimeter model sensitiVity was 4.45 x 10(4) mV/C kg(-1) (11.47 mV R(-1)) for TN-502RDS(micro); 5.93 x 10(4) mV per C kg(-1) (15.31 mV R(-1)) for TN-1002RD; 6.06 x 10(4) mV/C kg(-1) (15.63 mV R(-1)) for TN-1002RDI; 9.49 x 10(4) mV per C kg(-1) (24.49 mV R(-1)) for TN-1002RDM (micro); and 11.20 x 10(4) mV/C kg(-1) (28.82 mV R(-1)) for TN-1002RDS (micro). The energy response is presented and is observed to vary with dosimeter model, generally increasing with tube potential through the mammography energy range. An intercomparison of the high-sensitivity mode of TN-RD-22 was made to the very-high sensitivity bias power supply using a Mo/Mo target-filter. The very-high sensitivity-bias power supply increased dosimeter response by 1.45 +/- 0.04 for dosimeter models TN

  2. Reproducibility study of TLD-100 dosimeters for {sup 122}I seeds used in brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Zeituni, Carlos A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Universidade Presbiteriana Mackenzie, Sao Paulo, SP (Brazil); E-mail: czeituni@ipen.br; Moura, Eduardo S. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Faculdade Oswaldo Cruz, Sao Paulo, SP (Brazil); Manzoli, Jose E. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Universidade Sao Judas Tadeu, Sao Paulo, SP (Brazil); Terremoto, Luis A.A.; Rostelato, Maria Elisa C.M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2007-07-01

    In order to provide the dosimetry for {sup 125}I seed production in Brazil, Harshaw thermoluminescent dosimeters (TLD-100) will be used. Even if measurements with TLD-100 of the same batch of fabrication are performed, the precision of the response will not be the same. As a consequence, they must be measured one by one. This paper presents the calculation methodology for selection procedure to TLD-100 dosimeter used, embracing 143 TLD-100 dosimeters prepared by Harshaw Company on December 19th, 2005. These dosimeters are LiF type with a micro-cube (1 mm x 1 mm x 1 mm) shape. The annealing procedure used for these dosimeters consists of annealing the TLD dosimeters at 400 deg C for 65 minutes using a PC controlled annealing oven. This procedure is followed by an oven-typical cooling down profile to about 100 deg C for 127 minutes. The pre-readout thermal stabilization was used and it consists of an annealing at 100 deg C for 15 minutes. Irradiations were performed using 36 {sup 125}I seeds with activity of 0,623 mCi (23,05 MBq) on October 20th, 2006 for approximately 150 minutes, to guarantee a minimum of 5 Gy absorbed dose in each dosimeter. Different evanescence times have been used. These complete procedures were carried out four times in order to compare the data and minimize the systematic error. (author)

  3. Polycarbonate-based benzo-δ-sultam films for high-dose dosimetry in radiation processing

    Energy Technology Data Exchange (ETDEWEB)

    Feizi, Shazad [University of Tehran, Tehran (India). School of Chemistry; Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Radiation Application Research School; Ziaie, Farhood [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Radiation Application Research School; Ghandi, Mehdi [University of Tehran, Tehran (India). School of Chemistry

    2015-05-01

    In this work characteristics of the polycarbonate films with 20 μm in thickness containing different weight percentage of Benzo-δ-sultam were studied for use as a high dose dosimetry system in radiation processing facilities. The sensitivity of the dosimeters and the linearity of dose-response curves were investigated under {sup 60}Co γ-rays in a dose range of 0-100 kGy, and obtained results were compared with the commercial CTA and FWT film dosimeters. The results show that the absorbance at 348 nm depends linearly on the dose in the investigated dose range. The effects of pre-irradiation (shelf-life) and post-irradiation storage in dark and in indirect sunlight are also discussed. The results show that the dosimeters characteristics are stable within 1% at 25 C, 3 months after the irradiation.

  4. Development of colored alumilite dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Obara, Kenjiro; Shibanuma, Kiyoshi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Yagi, Toshiaki [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Yokoo, Noriko [Radiation Application Development Association, Tokai, Ibaraki (Japan)

    2003-03-01

    In the ITER (International Thermonuclear Experimental Reactor), in-vessel components such as blanket and divertor, which are installed in the vacuum vessel of the ITER, are maintained by remote handling equipment (RH equipment). The RH equipment for maintenance is operated under sever environmental conditions, such as high temperature (50{approx}100 degC), high gamma-ray radiation ({approx}1 kGy/h) in an atmosphere of inert gas or vacuum; therefore many components of the RH equipment must have a suitable radiation resistance efficiency for long time operation (10{approx}100 MGy). Typical components of the RH equipment have been extensively tested under an intensive gamma-ray radiation. Monitoring of the radiation dose of the components of the RH equipment is essential to control the operation period of the RH equipment considering radiation resistance. However, the maximum measurable radiation dose of the conventional dosimeters, such as ionization chamber, liquid, glass and plastic dosimeters are limited to be approximately 1MGy which is too low to monitor the RH equipment for the ITER. In addition, these conventional dosimeters do not involve sufficient radiation resistance against the high gamma-ray radiation as well as are not easy handling and low cost. Based on the above backgrounds, a new dosimeter with bleaching of an azo group dye to be applied to a radiation monitor has been developed for high gamma-ray radiation use. The colored alumilite dosimeter is composed of the azo group dye (-N=N-) in an anodic oxidation layer of aluminum alloy (Al{sub 2}O{sub 3}). It can monitor the radiation dose by measuring the change of the bleaching of azo dye in the Al{sub 2}O{sub 3} layer due to gamma-ray irradiation. The degree of bleaching is measured as the change of hue (color) and brightness based on the Munsell's colors with a three dimensional universe using spectrophotometer. In the tests, the dependencies such as colors, anodized layer thickness, type of azo

  5. Variation in the calibrated response of LiF, Al2O3, and silicon dosimeters when used for in-phantom measurements of source photons with energies between 30 KeV AND 300 KeV.

    Science.gov (United States)

    Poudel, Sashi; Currier, Blake; Medich, David C

    2015-04-01

    The MCNP5 radiation transport code was used to quantify changes in the absorbed dose conversion factor for LiF, Al2O3, and silicon-based electronic dosimeters calibrated in-air using standard techniques and summarily used to measure absorbed dose to water when placed in a water phantom. A mono-energetic photon source was modeled at energies between 30 keV and 300 keV for a point-source placed at the center of a water phantom, a point-source placed at the surface of the phantom, and for a 10-cm radial field geometry. Dosimetric calculations were obtained for water, LiF, Al2O3, and silicon at depths of 0.2 cm and 10 cm from the source. These results were achieved using the MCNP5 *FMESH photon energy-fluence tally, which was coupled with the appropriate DE/DF card for each dosimetric material studied to convert energy-fluence into the absorbed dose. The dosimeter's absorbed dose conversion factor was calculated as a ratio of the absorbed dose to water to that of the dosimeter measured at a specified phantom depth. The dosimeter's calibration value also was obtained. Based on these results, the absorbed dose conversion factor for a LiF dosimeter was found to deviate from its calibration value by up to 9%, an Al2O3 dosimeter by 43%, and a silicon dosimeter by 61%. These data therefore can be used to obtain LiF, Al2O3, and silicon dosimeter correction factors for mono-energetic and poly-energetic sources at measurement depths up to 10 cm under the irradiation geometries investigated herein.

  6. Performance Testing Of Selected Types of Electronic Personal Dosimeters in X- and Gamma Radiation Fields.

    Science.gov (United States)

    Kržanović, Nikola; Živanović, Miloš; Ciraj-Bjelac, Olivera; Lazarević, Đorđe; Ćeklić, Sandra; Stanković, Srboljub

    2017-10-01

    Electronic personal dosimeters (EPDs) are increasingly being used alongside conventional thermoluminescent dosimeters to measure the dose of legal record in terms of personal dose equivalent. Therefore, it is of great importance to execute performance tests of these dosimeters in photon fields of various energies and at various angles of incidence. This testing is done in order to simulate the behavior of these dosimeters in realistic multidirectional polyenergetic ionizing radiation fields. Tests of accuracy, linearity, energy response, and angular response have been performed on 10 EPDs from multiple manufacturers. Various radiation qualities have been used in the energy range from 33 keV to 1.33 MeV and for angles of incidence 0° to 80°. This research proves that many of the EPDs tested performed according to the manufacturer's specifications and the requirements of the international standards regarding personal dosimetry.

  7. Characterization and application of two kinds of ESR dosimeters

    Science.gov (United States)

    Marchioni, Eric; Pabst, Jean-Yves; Kuntz, Florent

    2002-09-01

    Many previous papers described the use of low-concentration alanine pellets, powder or films for industrial high-dose application, but very few authors presented applications of such dosimeters to the low-dose range used for wastewater, flowers or radiotherapy treatment. The present paper describes the large-scale manufacturing process of high-concentration alanine pellets used for radiotherapy dose control in some French hospitals. The fading process due to sunlight exposure has been evaluated by means of direct UV light irradiation. The major disadvantage of alanine is its strong solubility in water (the pellets are completely dissolved when immersed for 10 min in pure water). The use of barium sulphate, not soluble in water, made it possible to carry out dosimetric measurements even when the dosimeter is completely immersed in water or stored after irradiation in high humidity levels. The paper presents manufacturing process of barium sulphate pellets, their dosimetric characteristics and one application of this dosimeter for the control of the absorbed doses during wastewater treatments.

  8. SU-D-213-07: Initial Characterization of a Gel Patch Dosimeter for in Vivo Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Matrosic, C; Culberson, W; Rosen, B; Madsen, E; Frank, G; Bednarz, B [Univ of Wisc Madison, Madison, WI (United States)

    2015-06-15

    Purpose: In vivo dosimetry, despite being the most direct method for monitoring the dose delivered during radiation therapy and being recommended by several national and international organizations (AAPM, ICRU, NACP), is underutilized in the clinic due to issues associated with dose sensitivity, feasibility, and cost. Given the increasing complexity of radiation therapy modern treatments, there is a compelling need for a robust, affordable in vivo dosimetry option. In this work we present the initial characterization of a novel gel patch in vivo dosimeter. Methods: DEFGEL (6%T) was used to make 1-cm thick small cylindrical patch dosimeters. The optical density of each dosimeter was read before and after irradiation by an in-house laser densitometer. The dosimeters were irradiated using a Varian Clinac EX linac. Three separate batches of gel patches were used to create dose response curves and evaluate repeatability. The development time of the dosimeter was also evaluated. Results: The dose response of the dosimeter was found to be linear from a range of approximately 1-Gy to 20-Gy, which is a larger window of linearity compared to other in vivo dosimeters. At doses below 1-Gy, the cumulative uncertainties were on the order of the measured data. When compared, the three batches demonstrated repeatability from 1-Gy to approximately 13-Gy, with some variation at higher doses. For doses of >8-Gy, the dosimeter reached full optical density after 4-hours, whereas low doses developed within an hour. Conclusion: Initial results indicate that the gel patch dosimeter is a reliable and simple way to measure a large range of doses, including high doses such as those delivered during hypofractionated treatments (e.g. SBRT or MR-guided radiotherapy). The simple fabrication method for the dosimeter and the use of a laser densitometer would allow for the dosimeter to used and read in-house, cheaply and easily.

  9. PHOTOELECTRIC AND PHOTOMAGNETIC RESPONSE OF INDIUM-TIN OXIDE FILMS

    Directory of Open Access Journals (Sweden)

    I. K. Meshkovsky

    2015-11-01

    Full Text Available Subject of Research. The goal of the present research is investigation of photoelectric and photomagnetic response of ITO (indium-tin oxide films under UV laser irradiation. Method. The ITO films were prepared by magnetron sputtering with the thickness equal to 300nm. The films were irradiated by UV laser light with 248 nm wavelength in laser pulse energy range from 10 mJ to 150 mJ by KrF excimer laser. Metallic electrodes were deposited on the films. Information about the films surface topography was obtained by atomic force microscopy and scanning electron microscopy. The film structure was investigated by X-ray diffraction. Main Results. It was shown that voltage appears between metallic contacts under the UV light effect. The electric current was observed through resistive load. The anisotropy of electric field producing photoelectric response was demonstrated for the first time. The appearance of magnetic field under the laser light irradiation was observed for the first time. The dependence of the response voltage on the laser pulse energy was linear over the whole measured energy range. The following physical mechanism was proposed for description of the observed phenomenon: electric voltage is associated with non-uniform distribution of the average crystallite size along the film surface, and, therefore, with mean free path of the charge carriers along the film surface. Photomagnetic response could be associated with collective behavior of the large number of charged particles, created due to high intensity laser irradiation. Practical Relevance. The phenomenon being studied could be applied for creation of new optoelectronic devices, for example, modulators, optical detectors, etc. Particularly, due to linear dependence of photoelectric response on the laser pulse energy, this phenomenon is attractive for manufacturing of simple and cheap excimer laser pulse energy detectors.

  10. Feasibility of smartphone diaries and personal dosimeters to quantitatively study exposure to ultraviolet radiation in a small national sample

    DEFF Research Database (Denmark)

    Køster, Brian; Søndergaard, Jens; Nielsen, Jesper B

    2015-01-01

    studies and of smartphones as a data collection tool. MATERIALS AND METHODS: Participants were sent a dosimeter which they wore for 7 days, received a short diary questionnaire by text message each day and subsequently a longer questionnaire. Correlation between responses from questionnaire, smartphone...... diaries and dosimeters were examined. RESULTS: This study shows a 99.5% return rate (n = 205) of the dosimeters by ordinary mail and high response-rates for a smartphone questionnaire dairy. Correlation coefficients for outdoor-time reported through smartphones and dosimeters as average by week 0.62 (0...... that dosimeter studies are feasible in national settings and that smartphones are a useful tool for monitoring and collecting UV behavior data. CONCLUSION: We found diary data reported on a daily basis through smartphones more strongly associated with actual outdoor time than questionnaire data. Our results...

  11. New polymer gel dosimeters consisting of less toxic monomers with radiation-crosslinked gel matrix

    Science.gov (United States)

    Hiroki, A.; Yamashita, S.; Sato, Y.; Nagasawa, N.; Taguchi, M.

    2013-06-01

    New polymer gel dosimeters consisting of less toxic methacrylate-type monomers such as 2-hydroxymethyl methacrylate (HEMA) and polyethylene glycol 400 dimethacrylate (9G) with hydroxypropyl cellulose (HPC) gel were prepared. The HPC gels were obtained by using a radiation-induced crosslinking technique to be applied in a matrix instead of a gelatin, which is conventionally used in earlier dosimeters, for the polymer gel dosimeters. The prepared polymer gel dosimeters showed cloudiness by exposing to 60Co γ-ray, in which the cloudiness increased with the dose up to 10 Gy. At the same dose, the increase in the cloudiness appeared with increasing concentration of 9G. As a result of the absorbance measurement, it was found that the dose response depended on the composition ratio between HEMA and 9G.

  12. Novel composition of polymer gel dosimeters based on N-(Hydroxymethyl)acrylamide for radiation therapy

    Science.gov (United States)

    Basfar, Ahmed A.; Moftah, Belal; Rabaeh, Khalid A.; Almousa, Akram A.

    2015-07-01

    A new composition of polymer gel dosimeters is developed based on radiation induced polymerization of N-(Hydroxymethyl)acrylamide (NHMA) for radiotherapy treatment planning. The dosimeters were irradiated by 10 MV photon beam of a medical linear accelerator at a constant dose rate of 600 cGy/min with doses up to 20 Gy. The polymerization occurs and increases with increasing absorbed dose. The dose response of polymer gel dosimeters was studied using nuclear magnetic imaging (NMR) for relaxation rate (R2) of water proton. Dose rate, energy of radiation and the stability of the polymerization after irradiation were investigated. No appreciable effects of these parameters on the performance of the novel gel dosimeters were observed.

  13. K-band EPR dosimetry: small-field beam profile determination with miniature alanine dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Felipe [Departmento de Fisica e Matematica, FFCLRP-Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto-SP (Brazil); Department of Radiological Health, Caja de Seguro Social, Panama City (Panama); Department of Physics, Faculty of Natural and Exact Sciences and Technology, University of Panama, Panama City (Panama); Graeff, Carlos F.O. [Departmento de Fisica e Matematica, FFCLRP-Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto-SP (Brazil); Baffa, Oswaldo [Departmento de Fisica e Matematica, FFCLRP-Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto-SP (Brazil)

    2005-02-01

    The use of small-size alanine dosimeters presents a challenge because the signal intensity is less than the spectrometer sensitivity. K-band (24 GHz) EPR spectrometer seems to be a good compromise between size and sensitivity of the sample. Miniature alanine pellets were evaluated for small-field radiation dosimetry. Dosimeters of DL-alanine/PVC with dimensions of 1.5 mm diameter and 2.5 mm length with 5 mg mass were developed. These dosimeters were irradiated with 10 MV X-rays in the dose range 0.05-60 Gy and the first harmonic (1 h) spectra were recorded. Microwave power, frequency and amplitude of modulation were optimized to obtain the best signal-to-noise ratio (S/N). For beam profile determination, a group of 25 dosimeters were placed in an acrylic device with dimensions of (7.5x2.5x1) cm{sup 3} and irradiated with a (3x3) cm{sup 2} 10 MV X-rays beam field size. The dose at the central region of the beam was 20 Gy at a depth of 2.2 cm (build up for acrylic). The acrylic device was oriented perpendicular to the beam axis and to the gantry rotation axis. For the purposes of comparison of the spatial resolution, the beam profile was also determined with a radiographic film and 2 mm aperture optical densitometer; in this case the dose was 1 cGy. The results showed a similar spatial resolution for both types of dosimeters. The dispersion in dose reading was larger for alanine in comparison with the film, but alanine dosimeters can be read faster and more directly than film over a wide dose range.

  14. Monte-Carlo based prediction of radiochromic film response for hadrontherapy dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Frisson, T. [Universite de Lyon, F-69622 Lyon (France); CREATIS-LRMN, INSA, Batiment Blaise Pascal, 7 avenue Jean Capelle, 69621 Villeurbanne Cedex (France); Centre Leon Berrard - 28 rue Laennec, F-69373 Lyon Cedex 08 (France)], E-mail: frisson@creatis.insa-lyon.fr; Zahra, N. [Universite de Lyon, F-69622 Lyon (France); IPNL - CNRS/IN2P3 UMR 5822, Universite Lyon 1, Batiment Paul Dirac, 4 rue Enrico Fermi, F-69622 Villeurbanne Cedex (France); Centre Leon Berrard - 28 rue Laennec, F-69373 Lyon Cedex 08 (France); Lautesse, P. [Universite de Lyon, F-69622 Lyon (France); IPNL - CNRS/IN2P3 UMR 5822, Universite Lyon 1, Batiment Paul Dirac, 4 rue Enrico Fermi, F-69622 Villeurbanne Cedex (France); Sarrut, D. [Universite de Lyon, F-69622 Lyon (France); CREATIS-LRMN, INSA, Batiment Blaise Pascal, 7 avenue Jean Capelle, 69621 Villeurbanne Cedex (France); Centre Leon Berrard - 28 rue Laennec, F-69373 Lyon Cedex 08 (France)

    2009-07-21

    A model has been developed to calculate MD-55-V2 radiochromic film response to ion irradiation. This model is based on photon film response and film saturation by high local energy deposition computed by Monte-Carlo simulation. We have studied the response of the film to photon irradiation and we proposed a calculation method for hadron beams.

  15. Monte-Carlo based prediction of radiochromic film response for hadrontherapy dosimetry

    Science.gov (United States)

    Frisson, T.; Zahra, N.; Lautesse, P.; Sarrut, D.

    2009-07-01

    A model has been developed to calculate MD-55-V2 radiochromic film response to ion irradiation. This model is based on photon film response and film saturation by high local energy deposition computed by Monte-Carlo simulation. We have studied the response of the film to photon irradiation and we proposed a calculation method for hadron beams.

  16. Calcium carbonate as a possible dosimeter for high irradiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Negron M, A.; Ramos B, S.; Camargo R, C. [UNAM, Instituto de Ciencias Nucleares, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Uribe, R. M. [Kent State University, College of Technology, Kent OH (United States); Gomez V, V. [UNAM, Instituto de Quimica, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Kobayashi, K., E-mail: negron@nucleares.unam.mx [Yokohama National University (Japan)

    2014-08-15

    The aim of this work is to analyze the interactions of 5 MeV electron beam radiation and a 290 MeV/u Carbon beam with calcium carbonate (powder) at 298 K and at different irradiation doses, for the potential use of calcium carbonate as a high-dose dosimeter. The irradiation doses with the electron beam were from 0.015 to 9 MGy, and with Carbon beam from 1.5 kGy to 8 kGy. High-energy radiation induces the formation of free radicals in solid calcium carbonate that can be detected and measured by electron paramagnetic resonance (EPR). An increase of the EPR response for some of the free radicals produced in the sample was observed as a function of the irradiation dose. The response of one of the radicals decreased with the dose. These measurements are reproducible; the preparation of the sample is simple and inexpensive; and the signal is stable for several months. The response curves show that the dosimeter tends to saturate at 10 MGy. Based on these properties, we propose this chemical compound as a high-dose dosimeter, mainly for electron irradiation. (author)

  17. SU-E-T-296: Dosimetric Analysis of Small Animal Image-Guided Irradiator Using High Resolution Optical CT Imaging of 3D Dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Na, Y; Qian, X; Wuu, C [Columbia University, New York, NY (United States); Adamovics, J [John Adamovics, Skillman, NJ (United States)

    2015-06-15

    Purpose: To verify the dosimetric characteristics of a small animal image-guided irradiator using a high-resolution of optical CT imaging of 3D dosimeters. Methods: PRESAEGE 3D dosimeters were used to determine dosimetric characteristics of a small animal image-guided irradiator and compared with EBT2 films. Cylindrical PRESAGE dosimeters with 7cm height and 6cm diameter were placed along the central axis of the beam. The films were positioned between 6×6cm{sup 2} cubed plastic water phantoms perpendicular to the beam direction with multiple depths. PRESAGE dosimeters and EBT2 films were then irradiated with the irradiator beams at 220kVp and 13mA. Each of irradiated PRESAGE dosimeters named PA1, PA2, PB1, and PB2, was independently scanned using a high-resolution single laser beam optical CT scanner. The transverse images were reconstructed with a 0.1mm high-resolution pixel. A commercial Epson Expression 10000XL flatbed scanner was used for readout of irradiated EBT2 films at a 0.4mm pixel resolution. PDD curves and beam profiles were measured for the irradiated PRESAGE dosimeters and EBT2 films. Results: The PDD agreements between the irradiated PRESAGE dosimeter PA1, PA2, PB1, PB2 and the EB2 films were 1.7, 2.3, 1.9, and 1.9% for the multiple depths at 1, 5, 10, 15, 20, 30, 40 and 50mm, respectively. The FWHM measurements for each PRESAEGE dosimeter and film agreed with 0.5, 1.1, 0.4, and 1.7%, respectively, at 30mm depth. Both PDD and FWHM measurements for the PRESAGE dosimeters and the films agreed overall within 2%. The 20%–80% penumbral widths of each PRESAGE dosimeter and the film at a given depth were respectively found to be 0.97, 0.91, 0.79, 0.88, and 0.37mm. Conclusion: Dosimetric characteristics of a small animal image-guided irradiator have been demonstrated with the measurements of PRESAGE dosimeter and EB2 film. With the high resolution and accuracy obtained from this 3D dosimetry system, precise targeting small animal irradiation can be

  18. An investigation into the sensitivity of various albedo neutron dosimeters aimed at correcting the readings

    Science.gov (United States)

    Alekseev, A. G.; Mokrov, Yu. V.; Morozova, S. V.

    2012-03-01

    The results of an experimental determination of the sensitivity of three types of individual neutron albedo dosimeters in neutron reference fields on the basis of radionuclide sources and at the top concrete shielding of the U-70 accelerator are presented. The results show that the ratios between the responses of the albedo dosimeters designed earlier at the Joint Institute for Nuclear Research (the albedo dosimeter (AD) and the multicomponent dosimeter (MD)) and the currently used DVGN-01 dosimeter are constant within 25% in a wide range of neutron energy. This fact makes it possible to use the results of measuring the AD and MD responses obtained earlier in neutron fields of nuclear-physical installations at the Joint Institute for Nuclear Research (JINR) for the correction of DVGN-01 dosimeter measurement results to apply it to personal radiation monitoring (PRM) at these installations. The correction factors for DVGN-01 measurement results are found and recommended to be used in PRM for most JINR installations.

  19. Potential High Resolution Dosimeters For MRT

    Science.gov (United States)

    Bräuer-Krisch, E.; Rosenfeld, A.; Lerch, M.; Petasecca, M.; Akselrod, M.; Sykora, J.; Bartz, J.; Ptaszkiewicz, M.; Olko, P.; Berg, A.; Wieland, M.; Doran, S.; Brochard, T.; Kamlowski, A.; Cellere, G.; Paccagnella, A.; Siegbahn, E. A.; Prezado, Y.; Martinez-Rovira, I.; Bravin, A.; Dusseau, L.; Berkvens, P.

    2010-07-01

    resolution and a dose range over several orders of magnitude. This paper will give an overview of all dosimeters tested in the past at the ESRF with their advantages and drawbacks. These detectors comprise: Ionization chambers, Alanine Dosimeters, MOSFET detectors, Gafchromic® films, Radiochromic polymers, TLDs, Polymer gels, Fluorescent Nuclear Track Detectors (Al2O3:C, Mg single crystal detectors), OSL detectors and Floating Gate-based dosimetry system. The aim of such a comparison shall help with a decision on which of these approaches is most suitable for high resolution dose measurements in MRT. The principle of these detectors will be presented including a comparison for some dosimeters exposed with the same irradiation geometry, namely a 1×1 cm5 field size with microbeam exposures at the surface, 0.1 cm and 1 cm in depth of a PMMA phantom. For these test exposures, the most relevant irradiation parameters for future clinical trials have been chosen: 50 micron FWHM and 400 micron c-t-c distance. The experimental data are compared with Monte Carlo calculations.

  20. A universal dose–response curve for radiochromic films

    Energy Technology Data Exchange (ETDEWEB)

    Martín-Viera Cueto, J. A., E-mail: josea.martinviera.sspa@juntadeandalucia.es; Parra Osorio, V.; Moreno Sáiz, C.; Navarro Guirado, F.; Casado Villalón, F. J.; Galán Montenegro, P. [Radiofísica Hospitalaria, Hospital Regional Universitario, Málaga 29010 (Spain)

    2015-01-15

    Purpose: This paper presents a model for dose–response curves of radiochromic films. It is based on a modified version of single-hit model to take into account the growth experienced by lithium salt of pentacosa-10,12-diynoic acid polymers after irradiation. Methods: Polymer growth in radiochromic films is a critical phenomenon that can be properly described by means of percolation theory to provide an appropriate distribution function for polymer sizes. Resulting functional form is a power function featuring a critical exponent and two adjustable parameters. Moreover, these parameters act as scaling factors setting a natural scale for sensitometric curves where the dependence on channel sensitivity is removed. A unique reduced response curve is then obtained from all the color channels describing film behavior independently of film dosimetry system. Results: Resulting functional form has been successfully tested in several sensitometric curves from different Gafchromic EBT models, providing excellent agreement with experimental data in a wide dose range up to about 40 Gy and low dose uncertainty. Conclusions: The model presented in this paper describes accurately the sensitometric curves of radiochromic films in wide dose ranges covering all typical ranges used in external radiotherapy. Resulting dose uncertainty is low enough to render a reasonably good performance in clinical applications. Due to cross-correlation, only one of the adjustable parameters is totally independent and characterizes film batches.

  1. Radiation Monitoring Equipment Dosimeter Experiment

    Science.gov (United States)

    Hardy, Kenneth A.; Golightly, Michael J.; Quam, William

    1992-01-01

    Spacecraft crews risk exposure to relatively high levels of ionizing radiation. This radiation may come from charged particles trapped in the Earth's magnetic fields, charged particles released by solar flare activity, galactic cosmic radiation, energetic photons and neutrons generated by interaction of these primary radiations with spacecraft and crew, and man-made sources (e.g., nuclear power generators). As missions are directed to higher radiation level orbits, viz., higher altitudes and inclinations, longer durations, and increased flight frequency, radiation exposure could well become a major factor for crew stay time and career lengths. To more accurately define the radiological exposure and risk to the crew, real-time radiation monitoring instrumentation, which is capable of identifying and measuring the various radiation components, must be flown. This presentation describes a radiation dosimeter instrument which was successfully flown on the Space Shuttle, the RME-3.

  2. Enhancement in dose sensitivity of polymer gel dosimeters composed of radiation-crosslinked gel matrix and less toxic monomers

    Science.gov (United States)

    Hiroki, A.; Yamashita, S.; Taguchi, M.

    2015-01-01

    Polymer gel dosimeters based on radiation-crosslinked hydroxypropyl cellulose gel were prepared, which comprised 2-hydroxyethyl methacrylate (HEMA) and polyethylene glycol #400 dimethacrylate (9G) as less toxic monomers and tetrakis (hydroxymethyl) phosphonium chloride (THPC) as an antioxidant. The dosimeters exposed to 60Co γ-rays became cloudy at only 1 Gy. The irradiated dosimeters were optically analyzed by using a UV- vis spectrophotometer to evaluate dose response. Absorbance of the dosimeters linearly increased in the dose range from 0 to 10 Gy, in which dose sensitivity increased with increasing 9G concentration. The dose sensitivity of the dosimeters with 2 wt% HEMA and 3 wt% 9G was also enhanced by increment in THPC.

  3. Effect of D-(+-Glucose on the Stability of Polyvinyl Alcohol Fricke Hydrogel Three-Dimensional Dosimeter for Radiotherapy

    Directory of Open Access Journals (Sweden)

    Yuejiao Yang

    2016-06-01

    Full Text Available D-(+-glucose (Glc was added to the original Fricke polyvinyl alcohol–glutaraldehyde–xylenol orange (FPGX hydrogel dosimeter system to make a more stable FPGX hydrogel three-dimensional dosimeter in this paper. Polyvinyl alcohol was used as a substrate, which was combined with Fricke solution. Various concentrations of Glc were tested with linear relevant fitting for optimal hydrogel production conditions. The effects of various formulations on the stability and sensitivity of dosimeters were evaluated. The results indicated that D-(+-Glc, as a free radical scavenger, had a great effect on stabilizing the dose response related to absorbency and reducing the auto-oxidization of ferrous ions. A careful doping with Glc could slow down the color change of the dosimeter before and after radiation without any effect on the sensitivity of the dosimeter.

  4. Effect of D-(+)-glucose on the stability of polyvinyl alcohol fricke hydrogel three dimensional dosimeter for radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yue Jiao; Chen, Jie; Yang, Liming; Chen, Bin; Sheng, Zhenmei; Luo, Wen Yun [School of Environmental and Chemical Engineering, Shanghai University, Shanghai (China); Chen, Jian Xin; Lu, Xun; Sui, Guo Ping [Chemical and Ionizing Radiation Metrology Institute, Shanghai Institute of Measurement and Testing Technology, Shanghai (China)

    2016-06-15

    D-(+)-glucose (Glc) was added to the original Fricke polyvinyl alcohol-glutaraldehyde-xylenol orange (FPGX) hydrogel dosimeter system to make a more stable FPGX hydrogel three-dimensional dosimeter in this paper. Polyvinyl alcohol was used as a substrate, which was combined with Fricke solution. Various concentrations of Glc were tested with linear relevant fitting for optimal hydrogel production conditions. The effects of various formulations on the stability and sensitivity of dosimeters were evaluated. The results indicated that D-(+)-Glc, as a free radical scavenger, had a great effect on stabilizing the dose response related to absorbency and reducing the auto-oxidization of ferrous ions. A careful doping with Glc could slow down the color change of the dosimeter before and after radiation without any effect on the sensitivity of the dosimeter.

  5. Development of an absolute neutron dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Acevedo, C; Birstein, L; Loyola, H [Section de Desarrollos Innovativos, Comision Chilena de EnergIa Nuclear (CCHEN), Casilla 188-D, Santiago (Chile)], E-mail: lbirstei@cchen.cl

    2008-11-01

    An Absolute Neutron Dosimeter was developed to be used as a calibration standard for the Radiation Metrology Laboratory at CCHEN. The main component of the Dosimeter consists of a Proportional Counter of cylindrical shape, with Polyethylene walls and Ethylene gas in its interior. It includes a cage shaped arrangement of graphite bars that operates like the Proportional Counter cathode and a tungsten wire of 25 {mu}m in diameter {mu}m as the anode. Results of a Montecarlo modeling for the Dosimeter operation and results of tests and measurements performed with a radioactive source are presented.

  6. Photoacoustic response of thin films: Thermal memory influence

    Directory of Open Access Journals (Sweden)

    Nešić Mioljub

    2013-01-01

    Full Text Available On the basis of the generalized photoacoustic response model, which includes the influence of thermal memory on both thermoconducting and thermoelastic components, photoacoustic response of thin films is analyzed. It is demonstrated that the influence of thermal memory is manifested at frequencies above certain boundary frequency, which depends on thermal memory properties of the sample and its depth. A linear relation, linking heat propagation velocity and measured signal, is derived. Taking into account the confinement of the frequency range imposed by the measuring system, it is indicated that thermal memory properties of non-cristaline thin films can be determined in a photoacoustic experiment.

  7. Solar ultraviolet radiation response of EBT2 Gafchromic, radiochromic film.

    Science.gov (United States)

    Butson, Ethan T; Yu, Peter K N; Butson, Martin J

    2013-11-07

    Measurement of solar ultraviolet (UV) radiation is an important aspect of dosimetry for the improved knowledge of UV exposure and its associated health related issues. EBT2 Gafchromic film has been designed by its manufacturers as an improved tool for ionizing radiation dosimetry. The film is stated as exhibiting a significant reduction in UV response. However, results have shown that when exposed to UV from the 'bottom side' i.e. from the thick laminate side, the film exhibits a sensitivity to solar UV radiation which is both measurable and accurate for UV dosimetry. Films were irradiated in this position to known solar UV exposures and results are quantified showing a reproducibility of measurement to within ±7% (1 SD) when compared to calibrated UV meters. With an exposure of 20 J cm(-2) broad spectrum solar UV, the films net OD change was found to be 0.248 OD ± 0.021 OD when analysing the results using the red channel region of an Epson V700 desktop scanner. This was compared to 0.0294 OD ± 0.0053 OD change with exposure to the same UV exposure from the top side. This means that solar UV dosimetry can be performed using EBT2 Gafchromic film utilizing the underside of the film for dosimetry. The main advantages of this film type for measurement of UV exposure is the visible colour change and thus easy analysis using a desktop scanner as well as its uniformity in response and its robust physical strength for use in outside exposure situations.

  8. Improvement of electronic circuit and performance of electronic dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Chang, S. Y.; Lee, B. J.; Kim, B. H.; Kim, J. S.; Lee, K. C. [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2001-03-01

    An electronic personnal dosimeter(EPD) adopting a PIN type Silicon semiconductor as a radiation detector has been designed and manufactured. A hybrid type design of electronic circuit for processing a radiation signal has been adopted not only to improve the EPD response to radiation detection but also to reduce a size as well as a weight. The EPD can be independently used as an individual personal dosimeter for exposure monitoring if necessary after setting some variables by operator. The performance of this EPD has been tested and finally accredited by Korea Testing Laboratory(KTL) through a series of performance test under international criteria given in IEC61526 standard on the mechanical, electronical and radiation performance. The EPD reader which can interface an EPD with entrance door for proper access control has been designed and manufactured. A hangul is supported in this EPD reader in operational display menu for the user convenience. 10 refs., 30 figs., 5 tabs. (Author)

  9. A new electronic neutron dosimeter (END) for reliable personal dosimetry

    Science.gov (United States)

    Ing, H.; Cousins, T.; Andrews, H. R.; Machrafi, R.; Voevodskiy, A.; Kovaltchouk, V.; Clifford, E. T. H.; Robins, M.; Larsson, C.; Hugron, R.; Brown, J.

    2008-04-01

    Tests of existing electronic neutron dosimeters by military and civilian groups have revealed significant performance limitations. To meet the operational requirements of emergency response personnel to a radiological/nuclear incident as well as those in the nuclear industry, a new END has been developed. It is patterned after a unique commercial neutron spectral dosemeter known as the N-probe. It uses a pair of small special scintillators on tiny photomultiplier tubes. Special electronics were designed to minimize power consumption to allow for weeks of operation on a single charge. The size, performance, and data analysis for the END have been designed to meet/exceed international standards for electronic neutron dosimeters. Results obtained with the END prototype are presented.

  10. Dose-response curve of EBT, EBT2, and EBT3 radiochromic films to synchrotron-produced monochromatic x-ray beams

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Thomas A. D.; Hogstrom, Kenneth R.; Alvarez, Diane; Matthews, Kenneth L. II; Ham, Kyungmin; Dugas, Joseph P. [Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, Louisiana 70809 and Department of Physics and Astronomy, Louisiana State University and A and M College, 202 Nicholson Hall, Baton Rouge, Louisiana 70803 (United States); Department of Physics and Astronomy, Louisiana State University and A and M College, 202 Nicholson Hall, Baton Rouge, Louisiana 70803 (United States); Center for Advanced Microstructures and Devices, Louisiana State University and A and M College, 6980 Jefferson Highway, Baton Rouge, Louisiana 70806 (United States); Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, Louisiana 70809 and Department of Physics and Astronomy, Louisiana State University and A and M College, 202 Nicholson Hall, Baton Rouge, Louisiana 70803 (United States)

    2012-12-15

    Purpose: This work investigates the dose-response curves of GAFCHROMIC{sup Registered-Sign} EBT, EBT2, and EBT3 radiochromic films using synchrotron-produced monochromatic x-ray beams. EBT2 film is being utilized for dose verification in photoactivated Auger electron therapy at the Louisiana State University Center for Advanced Microstructures and Devices (CAMD) synchrotron facility. Methods: Monochromatic beams of 25, 30, and 35 keV were generated on the tomography beamline at CAMD. Ion chamber depth-dose measurements were used to determine the dose delivered to films irradiated at depths from 0.7 to 8.5 cm in a 10 Multiplication-Sign 10 Multiplication-Sign 10-cm{sup 3} polymethylmethacrylate phantom. AAPM TG-61 protocol was applied to convert measured ionization into dose. Films were digitized using an Epson 1680 Professional flatbed scanner and analyzed using the net optical density (NOD) derived from the red channel. A dose-response curve was obtained at 35 keV for EBT film, and at 25, 30, and 35 keV for EBT2 and EBT3 films. Calibrations of films for 4 MV x-rays were obtained for comparison using a radiotherapy accelerator at Mary Bird Perkins Cancer Center. Results: The sensitivity (NOD per unit dose) of EBT film at 35 keV relative to that for 4-MV x-rays was 0.73 and 0.76 for doses 50 and 100 cGy, respectively. The sensitivity of EBT2 film at 25, 30, and 35 keV relative to that for 4-MV x-rays varied from 1.09-1.07, 1.23-1.17, and 1.27-1.19 for doses 50-200 cGy, respectively. For EBT3 film the relative sensitivity was within 3% of unity for all three monochromatic x-ray beams. Conclusions: EBT and EBT2 film sensitivity showed strong energy dependence over an energy range of 25 keV-4 MV, although this dependence becomes weaker for larger doses. EBT3 film shows weak energy dependence, indicating that it would be a better dosimeter for kV x-ray beams where beam hardening effects can result in large changes in the effective energy.

  11. Responsive Plasma Polymerized Ultrathin Nanocomposite Films

    Science.gov (United States)

    2012-01-01

    al. Soft Matter 2008;4:1796e8. [2] Schmidt S, Motschman H, Hellweg T, von Klitzing R. Polymer 2008;49:749e56. [3] Julthongpiput D, Lin Y-H, Teng J...et al. Nat Mater 2010;9:101e13. [7] Xu W, Yin X, He G, Zhao J, Wang H. Soft Matter 2012;8:3105e11. [8] Luzinov I, Minko S, Tsukruk VV. Prog Polym Sci...Films 2006;515:2618e24. [35] Yagüe JL, Gleason KK. Soft Matter 2012;8:2890e4. [36] Cheng X, Canavan HE, Stein MJ, Hull JR, Kweskin SJ, Wagner MS, et al

  12. Characterization of a silicate glass as a high dose dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Farah, K., E-mail: k.farah@cnstn.rnrt.t [Laboratoire de Radiotraitement. Centre National des Sciences et Technologie Nucleaires, 2020 Sidi-Thabet (Tunisia); Mejri, A.; Hosni, F. [Laboratoire de Radiotraitement. Centre National des Sciences et Technologie Nucleaires, 2020 Sidi-Thabet (Tunisia); Ben Ouada, H. [Laboratoire de Physique et Chimie des Interfaces, Faculte des Sciences de Monastir, 5000 Monastir (Tunisia); Fuochi, P.G.; Lavalle, M. [ISOF-CNR, Via P. Gobetti 101, 40129 Bologna (Italy); Kovacs, A. [Institute of Isotopes, HAS, P.O. Box 77, H-1525 Budapest (Hungary)

    2010-02-21

    Commercial silicate glass has been investigated as a possible high dose dosimeter using an UV-vis spectrophotometer. Glass samples were irradiated by {sup 60}Co gamma rays and the results compared with those obtained with 3.4 and 8.4 MeV electron beams. The irradiated samples showed rapid fading at room temperature immediately after irradiation. In order to improve the stability of absorbance, glass samples were submitted to post-irradiation thermal treatments (150 deg. C for 20 min). The influences of the dose, type and energy of the ionizing radiation on the fading characteristics and on the response of the irradiated and thermally treated glasses were studied. Dependence of the glass response on the temperature during gamma irradiation in the range -3 to 80 deg. C is reported. The reproducibility to reuse glass dosimeter by thermal bleaching the radiation induced colour centres at 300 deg. C for 30 min was also investigated. Calibration curves in the range 0.1-17 kGy were obtained by using in-plant calibration techniques against transfer standard alanine dosimeters in the Tunisian semi-industrial gamma irradiation facility.

  13. 自显色个人剂量计研究%Investigation of Self-indicating Radiation Personal Dosimeter

    Institute of Scientific and Technical Information of China (English)

    夏文; 叶宏生; 林敏; 徐利军; 陈克胜; 陈义珍

    2014-01-01

    A self-indicating radiation personal dosimeter was investigated using radiation sensitive material diacetylene monomer PCDA ,which was a component of the polymeri-zation system .The substrate material ,solvent ,sensitive material ,solution tempera-ture ,thickness of film and the preparation method were studied .The dosimeter colour changes from w hite to blue w hen exposed 0.1-2.5 Gy ,and the linearly dependent coeffi-cient of the exposure response is 0.999 8 ,the stability of absorbency in two weeks after exposure is testified well . It can be used as self-indicating radiation alert personal dosimeter .%采用聚合变色体系,以类丁二炔单体PCDA为变色染料,制备了一种用于辐照剂量预警的自显色个人剂量计。对基体材料、稀释剂种类、变色染料、溶解温度、成膜厚度以及膜制备工艺进行了研究,建立了自显色个人剂量计制备方法。剂量计接受0.1~2.5 Gy辐照后,颜色从白色变为蓝色,在681.5 nm处测得剂量响应曲线线性相关系数为0.9998,照后两周内稳定性良好,可作为预警式个人剂量计使用。

  14. Hydrogen response of porous palladium nano-films

    Science.gov (United States)

    Gupta, D.; Barman, P. B.; Hazra, S. K.

    2015-08-01

    Palladium nanoparticles were synthesized by reducing sodium tetrachloropalladate at 100°C using Ethylene Glycol as reducing agent. The nanoparticles were characterized by TEM (Transmission Electron Microscopy), and optical absorption spectroscopy. The average particle size (cleaned glass substrates. The high porosity of these films, as revealed by Atomic Force Microscopy (AFM) studies, made these films suitable for hydrogen sensor applications. The resistance of the films, measured by making silver paste contacts on the porous surface, changed upon exposure to 1000 ppm hydrogen in nitrogen. Optimum sensor response was obtained at 50°C, beyond which it deteriorated. The total response comprising of initial rise and subsequent fall in resistance, is due to the formation of Pd-hydrides (whose resistivity is higher relative to Pd), and closure of interparticle gaps due to lattice expansion of palladium, respectively. A detailed analysis of the results based on the sensing mechanism has been discussed in the paper.

  15. Transient hot-film sensor response in a shock tube

    Science.gov (United States)

    Roberts, A. S., Jr.; Ortgies, K. R.; Gartenberg, E.

    1989-01-01

    Shock tube experiments were performed to determine the response of a hot-film sensor, mounted flush on the side wall of a shock tube, to unsteady flow behind a normal shock wave. The present experiments attempt to isolate the response of the anemometer due only to the change in convective heat transfer at the hot-film surface. The experiments, performed at low supersonic shock speeds in air, are described along with the data acquisition procedure. The change in convective heat transfer is deduced from the data and the results are compared with those from transient boundary layer theory and another set of experimental results. Finally, a transient local heat transfer coefficient is formulated for use as the forcing function in a hot-film sensor instrument model simulation.

  16. Far infrared and Raman response in tetragonal PZT ceramic films

    Energy Technology Data Exchange (ETDEWEB)

    Buixaderas, E.; Kadlec, C.; Vanek, P.; Drnovsek, S.; Ursic, H.; Malic, B.

    2015-07-01

    PbZr{sub 0}.38Ti{sub 0}.62O{sub 3} and PbZr{sub 0}.36Ti{sub 0}.64{sub O}3 thick films deposited by screen printing on (0 0 0 1) single crystal sapphire substrates and prepared at two different sintering temperatures, were studied by Fourier-transform infrared reflectivity, time-domain TH{sub z} transmission spectroscopy and micro-Raman spectroscopy. The dielectric response is discussed using the Lichtenecker model to account for the porosity of the films and to obtain the dense bulk dielectric functions. Results are compared with bulk tetragonal PZT 42/58 ceramics. The dynamic response in the films is dominated by an overdamped lead-based vibration in the TH{sub z} range, as known in PZT, but its evaluated dielectric contribution is affected by the porosity and roughness of the surface. (Author)

  17. Miniature Active Space Radiation Dosimeter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Space Micro will extend our Phase I R&D to develop a family of miniature, active space radiation dosimeters/particle counters, with a focus on biological/manned...

  18. Josephson effects and microwave response of hts thin films

    Energy Technology Data Exchange (ETDEWEB)

    Gallop, J.C.; Radcliffe, W.J.; Langham, C.D. (National Physical Lab., Teddington (UK)); Sobolewski, R.; Kula, W.; Gierlowski, P. (Inst. of Physics, Polish Academy of Sciences, Warszawa (Poland))

    1989-12-01

    The response of thin films YBCO and BSCCO to microwave fields has been investigated. Some unexpected features have been observed and an explanation is given in terms of a robust fluxon lattice whose motion is correlated with the applied microwave field. (orig.).

  19. A fibre optic dosimeter customised for brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Suchowerska, N. [Department of Radiation Oncology, Royal Prince Alfred Hospital, Camperdown, NSW 2050 (Australia); School of Physics, University of Sydney, NSW 2006 (Australia)], E-mail: Natalka@email.cs.nsw.gov.au; Lambert, J.; Nakano, T. [Department of Radiation Oncology, Royal Prince Alfred Hospital, Camperdown, NSW 2050 (Australia); School of Physics, University of Sydney, NSW 2006 (Australia); Law, S. [School of Physics, University of Sydney, NSW 2006 (Australia); Optical Fibre Technology Centre, University of Sydney, 206 National Innovation Centre, Australian Technology Park, Eveleigh, NSW 1430 (Australia); Elsey, J. [Bandwidth Foundry Pty Ltd, Australian Technology Park, NSW, 1430 (Australia); McKenzie, D.R. [School of Physics, University of Sydney, NSW 2006 (Australia)

    2007-04-15

    In-vivo dosimetry for brachytherapy cancer treatment requires a small dosimeter with a real time readout capability that can be inserted into the patient to determine the dose to critical organs. Fibre optic scintillation dosimeters, consisting of a plastic scintillator coupled to an optical fibre, are a promising dosimeter for this application. We have implemented specific design features to optimise the performance of the dosimeter for specific in-vivo dosimetry during brachytherapy. Two sizes of the BrachyFOD{sup TM} scintillation dosimeter have been developed, with external diameters of approximately 2 and 1 mm. We have determined their important dosimetric characteristics (depth dose relation, angular dependence, energy dependence). We have shown that the background signal created by Cerenkov and fibre fluorescence does not significantly affect the performance in most clinical geometries. The dosimeter design enables readout at less than 0.5 s intervals. The clinical demands of real time in-vivo brachytherapy dosimetry can uniquely be satisfied by the BrachyFOD{sup TM}.

  20. TH-C-19A-05: Evaluation of a New Reusable 3D Dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Juang, T [Medical Physics Graduate Program, Duke University Medical Center, Durham, NC (United States); Adamovics, J [Rider University, Skillman, NJ (United States); Oldham, M [Duke University Medical Center, Durham, NC (United States)

    2014-06-15

    Purpose: PRESAGE is a radiochromic plastic which has demonstrated strong potential for high resolution single-use 3D dosimetry. This study evaluates a new PRESAGE formulation (Presage-RU) in which the radiochromic response is reversible (the dosimeter optically clears after irradiation), enabling the potential for reusability. Methods: Presage-RU dose response and optical-clearing rates were evaluated in both small volume dosimeters (1×1×4.5cm) and a larger cylindrical dosimeter (8cm diameter, 4.5cm length). All dosimeters were allowed to fully optically clear in dark, room temperature conditions between irradiations. Dose response was determined by irradiating small volume samples from 0–8.0Gy and measuring change in optical density. The cylindrical dosimeter was irradiated with a simple 4-field box plan (parallel opposed pairs of 4cm×4cm AP-PA beams and 2cm×4cm lateral beams) to 20Gy. High resolution 3D dosimetry was achieved utilizing optical-CT readout. Readings were tracked up to 14 days to characterize optical clearing. Results: Initial irradiation yielded a response of 0.0119△OD/(Gy*cm) while two subsequent reirradiations yielded a lower but consistent response of 0.0087△OD/(Gy*cm). Strong linearity of dose response was observed for all irradiations. In the large cylindrical dosimeter, the integral dose within the high dose region exhibited an exponential decay in signal over time (halflife= 23.9 hours), with the dosimeter effectively cleared (0.04% of the initial signal) after 10 days. Subsequent irradiation resulted in 19.5% lower initial signal but demonstrated that the exponential clearing rate remained consistent. Results of additional subsequent irradiations will also be presented. Conclusion: This work introduces a new re-usable radiochromic dosimeter (Presage-RU) compatible with high resolution (sub-millimeter) 3D dosimetry. Sensitivity of the initial radiation was observed to be slightly higher than subsequent irradiations, but the

  1. Gamma-ray irradiation and post-irradiation at room and elevated temperature response of pMOS dosimeters with thick gate oxides

    Directory of Open Access Journals (Sweden)

    Pejović Momčilo M.

    2011-01-01

    Full Text Available Gamma-ray irradiation and post-irradiation response at room and elevated temperature have been studied for radiation sensitive pMOS transistors with gate oxide thickness of 100 and 400 nm, respectively. Their response was followed based on the changes in the threshold voltage shift which was estimated on the basis of transfer characteristics in saturation. The presence of radiation-induced fixed oxide traps and switching traps - which lead to a change in the threshold voltage - was estimated from the sub-threshold I-V curves, using the midgap technique. It was shown that fixed oxide traps have a dominant influence on the change in the threshold voltage shift during gamma-ray irradiation and annealing.

  2. Determining the applicability of the Landauer nanoDot as a general public dosimeter in a research imaging facility.

    Science.gov (United States)

    Charlton, Michael A; Thoreson, Kelly F; Cerecero, Jennifer A

    2012-11-01

    The Research Imaging Institute (RII) building at the University of Texas Health Science Center at San Antonio (UTHSCSA) houses two cyclotron particle accelerators, positron emission tomography (PET) machines, and a fluoroscopic unit. As part of the radiation protection program (RPP) and meeting the standard for achieving ALARA (as low as reasonably achievable), it is essential to minimize the ionizing radiation exposure to the general public through the use of controlled areas and area dose monitoring. Currently, thirty-four whole body Luxel+ dosimeters, manufactured by Landauer, are being used in various locations within the RII to monitor dose to the general public. The intent of this research was to determine if the nanoDot, a single point dosimeter, can be used as a general public dosimeter in a diagnostic facility. This was tested by first verifying characteristics of the nanoDot dosimeter including dose linearity, dose rate dependence, angular dependence, and energy dependence. Then, the response of the nanoDot dosimeter to the Luxel+ dosimeter when placed in a continuous, low dose environment was investigated. Finally, the nanoDot was checked for appropriate response in an acute, high dose environment. Based on the results, the current recommendation is that the nanoDot should not replace the Luxel+ dosimeter without further work to determine the energy spectra in the RII building and without considering the limitation of the microStar reader, portable on-site OSL reader, at doses below 0.1 mGy (10 mrad).

  3. Proton response of alanine based pellets and films

    Energy Technology Data Exchange (ETDEWEB)

    Onori, S.; De Angelis, C.; Fattibene, P. [Istituto Superiore di Sanita, Rome (Italy). Lab. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Rome (Italy). Sezione Sanita; D`Errico, F. [DCMN, Universita degli Studi di Pisa (Italy); Egger, E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Janovsky, I. [Nuclear Research Institute, Rez (Czech Republic)

    1997-01-01

    The performance of two different alanine-ESR systems (1 mm ISS pellets and NRI films) in therapy proton beams was checked against reference dosimetry provided by a Markus parallel plate ionization chamber. Irradiations were performed at the OPTIS facility of the PSI with a 62 MeV proton beam. The energy dependence of the response was derived from the analysis of film stacks irradiated with pristine beams. In fact, 250 {mu}m films allowed for a high resolution sampling of the proton slowing down mechanisms. Moreover pellets were irradiated in unmodulated and modulated beams. Alanine dose distributions were always in good agreement with the PSI Markus chamber results. Simple density scaling allowed for the conversion of the results to the dose distributions in water, consistently with the good tissue equivalence properties of these detectors. (Author).

  4. A study on Fricke-PVA-xylenol orange hydrogel dosimeter for E-beam radiotherapy

    Institute of Scientific and Technical Information of China (English)

    CAO Fangqi; YANG Liming; CHEN Jie; LIN Han; FAN Jinchen; RONG Liang; LUO Wenyun; ZHA Yuanzi; WU Guohua

    2009-01-01

    A Fricke-PVA-xylenol orange (FPX) hydrogel dosimeter, in good transparency, was prepared by physical crosslinking for three-dimensional dose measurements. The process of mixing the chemical dosimeter with the PVA solution was carried out at room temperature, which reduced the influence of auto-oxidation rate. Gradation in color was obviously observed with different distance from the radiation source after 6 MeV electron beam irradiation for radiotherapy. The effects of irradiation dose and three components of the FPX gel dosimeter, i.e. ferrous ions, xylenol orange (XO) and sulphuric acid on sensitivity and stability of dose response were investigated by UV-vis spectropho-tometric measurement. The dose response of the FPX gel dosimeter was linear in the range 0~2.0 Gy. The orthogonal test was employed to find the optimal composition of the gel dosimeter with a sensitivity of about 0.095 cm-1·Gy-1. It was found that XO concentration greatly affected the sensitivity of dose response and lower concentrations of the fer-rous ion and XO gave higher sensitivity within the range 0~2.0 Gy.

  5. Early development and characterization of a DNA-based radiation dosimeter

    Science.gov (United States)

    Avarmaa, Kirsten A.

    It is the priority of first responders to minimize damage to persons and infrastructure in the case of a nuclear emergency due to an accident or deliberate terrorist attack -- if this emergency includes a radioactive hazard, first responders require a simple-to-use, accurate and complete dosimeter for radiation protection purposes in order to minimize the health risk to these individuals and the general population at large. This work consists of the early evaluation of the design and performance of a biologically relevant dosimeter which uses DNA material that can respond to the radiation of any particle type. The construct consists of fluorescently tagged strands of DNA. The signalling components of this dosimeter are also investigated for their sensitivity to radiation damage and light exposure. The dual-labelled dosimeter that is evaluated in this work gave a measurable response to gamma radiation at dose levels of 10 Gy for the given detector design and experimental setup. Further testing outside of this work confirmed this finding and indicated a working range of 100 mGy to 10 Gy using a custom-built fluorimeter as part of a larger CRTI initiative. Characterization of the chromatic components of the dosimeter showed that photobleaching is not expected to have an effect on dosimeter performance, but that radiation can damage the non-DNA signalling components at higher dose levels, although this damage is minimal at lower doses over the expected operating ranges. This work therefore describes the early steps in the quantification of the behaviour of the DNA dosimeter as a potential biologically-based device to measure radiation dose.

  6. Tl and OSL dose response of LiF:Mg, Ti and Al{sub 2}O{sub 3}:C dosimeters using a PMMA phantom for IMRT technique quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Matsushima, L. C.; Veneziani, G. R.; Campos, L. L. [Instituto de Pesquisas Energeticas e Nucleares, Gerencia de Metrologia das Radiacoes / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil); Sakuraba, R. K.; Cruz, J. C., E-mail: lmatsushima@usp.br [Sociedade Beneficente Israelita Brasileira - Hospital Albert Einstein, Av. Albert Einstein 627/701, Morumbi, 05652-000 Sao Paulo (Brazil)

    2014-08-15

    The principle of IMRT is to treat a patient from a number of different directions (or continuous arcs) with beams of nonuniform fluences, which have been optimized to deliver a high dose to the target volume and an acceptably low dose to the surrounding normal structures (Khan, 2010). This study intends to provide information to the physicist regarding the application of different dosimeters type, phantoms and analysis technique for Intensity Modulated Radiation Therapy (IMRT) dose distributions evaluation. The measures were performed using dosimeters of LiF:Mg,Ti and Al{sub 2}O{sub 3}:C evaluated by techniques of thermoluminescent (Tl) and Optically Stimulated Luminescence (OSL). A polymethylmethacrylate (PMMA) phantom with five cavities, two principal target volumes considered like tumours to be treated and other three cavities to measure the scattered radiation dose was developed to carried out the measures. (Author)

  7. The radiation response of mesoporous nanocrystalline zirconia thin films

    Science.gov (United States)

    Manzini, Ayelén M.; Alurralde, Martin A.; Giménez, Gustavo; Luca, Vittorio

    2016-12-01

    The next generation of nuclear systems will require materials capable of withstanding hostile chemical, physical and radiation environments over long time-frames. Aside from its chemical and physical stability, crystalline zirconia is one of the most radiation tolerant materials known. Here we report the first ever study of the radiation response of nanocrystalline and mesoporous zirconia and Ce3+-stabilized nanocrystalline zirconia (Ce0.1Zr0.9O2) thin films supported on silicon wafers. Zirconia films prepared using the block copolymer Brij-58 as the template had a thickness of around 60-80 nm. In the absence of a stabilizing trivalent cation they consisted of monoclinic and tetragonal zirconia nanocrystals with diameters in the range 8-10 nm. Films stabilized with Ce3+ contained only the tetragonal phase. The thin films were irradiated with iodine ions of energies of 70 MeV and 132 keV at low fluences (1013 - 1014 cm-2) corresponding to doses of 0.002 and 1.73 dpa respectively, and at 180 keV and high fluences (2 × 1016 cm-2) corresponding to 82.4 dpa. The influence of heavy ion irradiation on the nanocrystalline structure was monitored through Rietveld analysis of grazing incidence X-ray diffraction (GIXRD) patterns recorded at angles close to the critical angle to ensure minimum contribution to the diffraction pattern from the substrate. Irradiation of the mesoporous nanocrystalline zirconia thin films with 70 MeV iodine ions, for which electronic energy loss is dominant, resulted in slight changes in phase composition and virtually no change in crystallographic parameters as determined by Rietveld analysis. Iodine ion bombardment in the nuclear energy loss regime (132-180 keV) at low fluences did not provoke significant changes in phase composition or crystallographic parameters. However, at 180 keV and high fluences the monoclinic phase was totally eliminated from the GIXRD pattern of films prepared at both 350 and 500 °C implying either a monoclinic

  8. Fiber optic dosimeter with silicon photomultipliers

    Science.gov (United States)

    Moutinho, L. M.; Castro, I. F.; Peralta, L.; Abreu, M. C.; Veloso, J. F. C. A.

    2014-08-01

    A small dimension, real-time readout dosimeter is desirable for specific applications in medical physics as for example, dose measurement in prostate brachytherapy. This particular radiotherapy procedure consists in the permanent deposition of low energy, low-dose and low-dose rate small sized radioactive seeds. We developed a scintillating fiber optic based dosimeter suitable for in-vivo, real-time low dose and low dose rate measurements. Due to the low scintillation light produced in the scintillating fiber, a high sensitive and high gain light detector is required. The Silicon Photomultipliers are an interesting option that allowed us to obtain good results in our studies.

  9. Linearization of EBT3 film dose response and virtual film dosimetry for SBRT quality assurance

    Science.gov (United States)

    Cai, M.; Archibald-Heeren, B.; Wang, Y.; Metcalfe, P.

    2017-01-01

    EBT3 film offers high spatial resolution and low energy dependence, making it a suitable choice for quality assurance where high dose gradients are present, such as the case for SBRT. This work presents a simple method to adjust scanner settings so that dose response becomes linear. This linearity eliminates the need to obtain a calibration curve and associated uncertainties in curve fitting. Relative dosimetry can be performed after dose normalization to a reference point. Linearity is also a more robust condition than calibration curve with respect to scanner warm-up conditions, resulting in reduced uncertainty in dose measurement. An in-house developed program reads the film scan and a 2D dose map then constructs both to virtual films using grayscale values. Film intensity value was normalized to dose at reference point. Relative dosimetry was performed by comparing the two resulting images. Patient specific quality assurance was conducted for two SBRT cases. In both plans more than 95% gamma function points passed the gamma criteria of 2%/3mm.

  10. Fast-response humidity-sensing films based on methylene blue aggregates formed on nanoporous semiconductor films

    Science.gov (United States)

    Ishizaki, Ryota; Katoh, Ryuzi

    2016-05-01

    We prepared fast-response colorimetric humidity-sensing (vapochromic) films based on methylene blue adsorption onto nanoporous semiconductor (TiO2, Al2O3) films. Color changes caused by changes of humidity could be easily identified visually. A characteristic feature of the vapochromic films was their fast response to changes of humidity. We found that the response began to occur within 10 ms. The response was rapid because all the methylene blue molecules attached to the nanoporous semiconductor surface were directly exposed to the environment. We also deduced that the color changes were caused by structural changes of the methylene blue aggregates on the surface.

  11. The elastic mechanical response of supported thin polymer films.

    Science.gov (United States)

    Chung, Peter C; Glynos, Emmanouil; Green, Peter F

    2014-12-23

    Nanoindentation studies of the mechanical properties of sufficiently thin polymer films, supported by stiff substrates, indicate that the mechanical moduli are generally higher than those of the bulk. This enhancement of the effective modulus, in the thickness range of few hundred nanometers, is indicated to be associated with the propagation and impingement of the indentation tip induced stress field with the rigid underlying substrate; this is the so-called "substrate effect". This behavior has been rationalized completely in terms of the moduli and Poisson's ratios of the individual components, for the systems investigated thus far. Here we show that for thin supported polymer films, in general, information regarding the local chain stiffness and local vibrational constants of the polymers provides an appropriate rationalization of the overall mechanical response of polymers of differing chemical structures and polymer-substrate interactions. Our study should provide impetus for atomistic simulations that carefully account for the role of intermolecular interactions on the mechanical response of supported polymer thin films.

  12. Biological and physical dosimeters for monitoring solar UV-B light.

    Science.gov (United States)

    Furusawa, Y; Suzuki, K; Sasaki, M

    1990-06-01

    A biological dosimetry system for measuring solar UV-B light was established using bacteriophage T1 with E. coli Bs-1 as the host cell. Also a new physical UV-B dosimeter was developed which can specifically detect the UV spectral region related to inactivation of phage T1. Phage T1 is very stable in liquid suspension and it has adequate sensitivity to measure the intensity of solar UV-B. In addition, the survival of phage T1 responded linearly to UV fluences when plotted semi-logarithmic ally. Thus T1 seemed to have characteristic features making it suitable material as a biological dosimeter for sunlight. Outdoor experiments throughout one year showed that the mean amount of solar UV light in summer was about 6 fold larger than that in winter at Isehara (139.5 degrees E, 35.5 degrees N), Japan. A novel physical dosimeter which responds faithfully to UV-B light under atmospheric conditions on the ground was developed as well. The spectral response was very close to that of biological materials. Readings of this UV-B dosimeter could be converted into the efficiency of sunlight upon biological materials. This instrument is compact; it can also be used as an erythemal dosimeter.

  13. Applicability of the Sunna dosimeter for food irradiation control

    Science.gov (United States)

    Kovács, A.; Baranyai, M.; Wojnárovits, L.; Miller, S.; Murphy, M.; McLaughlin, W. L.; Slezsák, I.; Kovács, A. I.

    2002-03-01

    The quick development concerning the commercial application of food irradiation in the USA recently resulted in growing marketing of irradiated red meat as well as irradiated fresh and dried fruits. These gamma and electron irradiation technologies require specific dosimetry systems for process control. The new version of the Sunna dosimeter has been characterized in gamma, electron and bremsstrahlung radiation fields by measuring the optically stimulated luminescence (osl) at 530 nm both below and above 1 kGy, i.e. for disinfestation and for meat irradiation purposes. No humidity and no significant dose rate effect on the green osl signal was observed. The temperature coefficient was determined from 0°C up to about 40°C and to stabilize the osl signal after irradiation a heat treatment method was introduced. Based on these investigations the Sunna 'gamma' film is a suitable candidate for dose control below and above 1 kGy for food irradiation technologies.

  14. Investigation of nanoscale structures by small-angle X-ray scattering in a radiochromic dosimeter

    DEFF Research Database (Denmark)

    Skyt, Peter Sandegaard; Jensen, Grethe Vestergaard; Wahlstedt, Isak Hannes

    2014-01-01

    This study examines the nanoscale structures in a radiochromic dosimeter that was based on leuco-malachite-green dye and the surfactant sodium dodecyl sulfate (SDS) suspended in a gelatin matrix. Small-angle X-ray scattering was used to investigate the structures of a range of compositions...... of the dosimeter. When omitting gelatin, ellipsoidal micelles of SDS were formed with a core radius near 15 Å, an eccentricity of 1.6, and a head-group shell thickness near 7 Å. Gelatin significantly changed the micelles to a cylindrical shape with around three times lower core radius and four times larger shell...... thickness, which shows that the gelatin is present in the shell and the outer part of the core. Insight into the detailed structure might help to improve the dosimeter performance and increase the dose response to clinically relevant dose levels....

  15. Initial characterization of a gel patch dosimeter for in vivo dosimetry

    Science.gov (United States)

    Matrosic, C.; Culberson, W.; Rosen, B.; Madsen, E.; Frank, G.; Bednarz, B.

    2016-05-01

    In vivo dosimetry is a greatly underutilized tool for patient safety in clinical external beam radiotherapy treatments, despite being recommended by several national and international organizations (AAPM, ICRU, IAEA, NACP). The reasons for this underutilization mostly relate to the feasibility and cost of in vivo dosimetry methods. Due to the increase in the number of beam angles and dose per fraction in modern treatments, there is a compelling need for a novel dosimeter that is robust and affordable while able to operate properly in these complex conditions. This work presents a gel patch dosimeter as a novel method of in vivo dosimetry. DEFGEL, a 6% T normoxic polyacrylamide gel, was injected into 1 cm thick acrylic molds to create 1 cm thick small cylindrical patch dosimeters. To evaluate the change in optical density due to radiation induced polymerization, dosimeters were scanned before and after irradiation using an in-house developed laser densitometer. The dose-responses of three separate batches of gel were evaluated and compared to check for linearity and repeatability. The response development time was evaluated to ensure that the patch dosimeter could be high throughput. Additionally, the potential of this system to be used as an in vivo dosimeter was tested with a clinically relevant end-to-end in vivo phantom test. All irradiations were performed with a Varian Clinac 21EX at the University of Wisconsin Medical Radiation Research Center (UWMRRC). The dose-response of all three batches of gel was found to be linear within the range of 2-20 Gy. At doses below 0.5 Gy the statistical uncertainties were prohibitively large to make quantitative assessments of the results. The three batches demonstrated good repeatability in the range of 2 Gy to up to 10 Gy, with only slight variations in response at higher doses. For low doses the dosimeter fully developed within an hour while at higher doses they fully developed within four hours. During the in vivo

  16. Radiant energy dosimeter for field use

    Science.gov (United States)

    A. Broido; A.W. McMasters

    1967-01-01

    Thermal radiation measurements in Project Flambeau fires involved a limited number of conventional radiometers located outside the fire periphery. A simple, cheap, easily-fabricated, light-weight, self-contained, rugged dosimeter was desired to withstand a hot fire environment, including a specific energy input of 5,000 cal cm -2, and to record...

  17. Dosimetric comparison among different head and neck radiotherapy techniques using PRESAGE® dosimeter

    Directory of Open Access Journals (Sweden)

    Jalil Rehman

    2015-12-01

    Full Text Available Purpose: The purpose of this analysis was to investigate dose distribution of Three Dimensional Conformal Radiation Therapy (3DCRT, Intensity Modulated Radiation Therapy (IMRT and Volumetric Modulated Arc Therapy (VMAT for Head and Neck cancer using 3-dimensional PRESAGE® dosimeter. Method: Computer Tomography (CT scans of Radiological Physics Center (RPC Head and Neck anthropomorphic phantom with both RPC standard insert and PRESAGE® insert were acquired separated with Philipp’s CT scanner and both CT scans were exported via DICOM to the pinnacle treatment planning system (TPS. Each plan was delivered twice to the RPC phantom first containing the RPC standard insert having Thermoluminescent detectors (TLD and film dosimeters and then again containing the PRESAGE® insert having three dimensional dosimeter (PRESAGE® by using a Varian True beam linear accelerator. After irradiation, the standard insert including point dose measurement (TLD and planner GafChromic® EBT film measurement was read using RPC standard procedure. The 3D dose distribution from PRESAGE® was read out with the Duke Midsized optical scanner dedicated to RPC (DMOS-RPC. Dose volume histogram (DVH, mean and maximal doses for organ-at-risk (OARs were calculated and compared among each Head and Neck technique. The prescription dose was same for all Head and Neck radiotherapy techniques which was 6.60 Gy per friction. Beam profile comparison and gamma analysis were used to quantify agreement among film measurement, PRESAGE® measurement and calculated dose distribution. Quality assurances of all plans were performed by using ArcCHECK method. Results: VMAT delivered the lowest mean and maximal doses to organ at risk (spinal cord and parotid than IMRT and 3DCRT. Such dose distribution was verified by absolute dose distribution using TLD system. 2D gamma 5%/3 mm criteria of Pinnacle vs. EBT2 film 3DCRT (92.34%, IMRT (92.3% and VMAT (96.63% in axial plan respectively. It was

  18. SU-E-T-274: Does Atmospheric Oxygen Affect the PRESAGE Dosimeter?

    Energy Technology Data Exchange (ETDEWEB)

    Alqathami, M; Ibbott, G [UT MD Anderson Cancer Center, Houston, TX (United States); Blencowe, A [The University of South Australia, South Australia, SA (Australia)

    2015-06-15

    Purpose: To experimentally determine the influence of atmospheric oxygen on the efficiency of the PRESAGE dosimeter and its reporting system. Methods: Batches of the reporting system – a mixture of chloroform and leuchomalachite green dye – and PRESAGE were prepared in aerobic and anaerobic conditions. For anaerobic batches, samples were deoxygenated by bubbling nitrogen through the dosimeter precursors or reporting system for 10 min. The dosimeters and reporting systems were prepared in spectrophotometric cuvettes and glass vials, respectively, and were irradiated with 6 MV photons to various radiation doses using a clinical linear accelerator. Changes in optical density of the dosimeters and reporting system before and after irradiation were measured using a spectrophotometer. In addition, the concentrations of dissolved oxygen were measured using a dissolved oxygen meter. Results: The experiments revealed that oxygen has little influence on the characteristics of PRESAGE, with the radical initiator oxidizing the leucomalachite green even in the presence of oxygen. However, deoxygenation of the reporting system leads to an increase in sensitivity to radiation dose by ∼ 30% when compared to the non-deoxygenated system. A slight improvement in sensitivity (∼ 5%) was also achieved by deoxygenating the PRESAGE precursor prior to casting. Measurement of the dissolved oxygen revealed low levels (0.4 ppm) in the polyurethane precursor used to fabricate the dosimeters, as compared to water (8.6 ppm). In addition, deoxygenation had no effect on the retention of the post-response absorption value of the PRESAGE dosimeter. Conclusion: The results suggest that the presence of oxygen does not inhibit the radiochromic properties of the PRESAGE system. In addition, there were no observed changes in the dose linearity, absorption spectrum and post-response photofading characteristics of the PRESAGE under the conditions investigated.

  19. Deficiencies of active electronic radiation protection dosimeters in pulsed fields.

    Science.gov (United States)

    Ankerhold, U; Hupe, O; Ambrosi, P

    2009-07-01

    Nowadays nearly all radiation fields used for X-ray diagnostics are pulsed. These fields are characterised by a high dose rate during the pulse and a short pulse duration in the range of a few milliseconds. The use of active electronic dosimeters has increased in the past few years, but these types of dosimeters might possibly not measure reliably in pulsed radiation fields. Not only personal dosimeters but also area dosimeters that are used mainly for dose rate measurements are concerned. These cannot be substituted by using passive dosimeter types. The characteristics of active electronic dosimeters determined in a continuous radiation field cannot be transferred to those in pulsed fields. Some provisional measurements with typical electronic dosimeters in pulsed radiation fields are presented to reveal this basic problem.

  20. Effect of Electron-Beam Irradiation on Organic Semiconductor and Its Application for Transistor-Based Dosimeters.

    Science.gov (United States)

    Kim, Jae Joon; Ha, Jun Mok; Lee, Hyeok Moo; Raza, Hamid Saeed; Park, Ji Won; Cho, Sung Oh

    2016-08-03

    The effects of electron-beam irradiation on the organic semiconductor rubrene and its application as a dosimeter was investigated. Through the measurements of photoluminescence and the ultraviolet photoelectron spectroscopy, we found that electron-beam irradiation induces n-doping of rubrene. Additionally, we fabricated rubrene thin-film transistors with pristine and irradiated rubrene, and discovered that the decrease in transistor properties originated from the irradiation of rubrene and that the threshold voltages are shifted to the opposite directions as the irradiated layers. Finally, a highly sensitive and air-stable electron dosimeter was fabricated based on a rubrene transistor.

  1. Thermoluminescence characterisation of chemical vapour deposited diamond films

    CERN Document Server

    Mazzocchi, S; Bucciolini, M; Cuttone, G; Pini, S; Sabini, M G; Sciortino, S

    2002-01-01

    The thermoluminescence (TL) characteristics of a set of six chemical vapour deposited diamond films have been studied with regard to their use as off-line dosimeters in radiotherapy. The structural characterisation has been performed by means of Raman spectroscopy. Their TL responses have been tested with radiotherapy beams ( sup 6 sup 0 Co photons, photons and electrons from a linear accelerator (Linac), 26 MeV protons from a TANDEM accelerator) in the dose range 0.1-7 Gy. The dosimetric characterisation has yielded a very good reproducibility, a very low dependence of the TL response on the type of particle and independence of the radiation energy. The TL signal is not influenced by the dose rate and exhibits a very low thermal fading. Moreover, the sensitivity of the diamond samples compares favourably with that of standard TLD100 dosimeters.

  2. Quenching effect in an optical fiber type small size dosimeter irradiated with 290 MeV·u{sup -1} carbon ions

    Energy Technology Data Exchange (ETDEWEB)

    Hirata, Yuho; Watanabe, Kenichi; Uritani, Akira; Yamazaki, Atsushi [Graduate School of Engineering, Nagoya University, Nagoya (Japan); Koba, Yusuke; Matsufuji, Naruhiro [National Institute of Radiological Sciences, Chiba (Japan)

    2016-09-15

    We are developing a small size dosimeter for dose estimation in particle therapies. The developed dosimeter is an optical fiber based dosimeter mounting an radiation induced luminescence material, such as an OSL or a scintillator, at a tip. These materials generally suffer from the quenching effect under high LET particle irradiation. We fabricated two types of the small size dosimeters. They used an OSL material Eu:BaFBr and a BGO scintillator. Carbon ions were irradiated into the fabricated dosimeters at Heavy Ion Medical Accelerator in Chiba (HIMAC). The small size dosimeters were set behind the water equivalent acrylic phantom. Bragg peak was observed by changing the phantom thickness. An ion chamber was also placed near the small size dosimeters as a reference. Eu:BaFBr and BGO dosimeters showed a Bragg peak at the same thickness as the ion chamber. Under high LET particle irradiation, the response of the luminescence-based small size dosimeters deteriorated compared with that of the ion chamber due to the quenching effect. We confirmed the luminescence efficiency of Eu:BaFBr and BGO decrease with the LET. The reduction coefficient of luminescence efficiency was different between the BGO and the Eu:BaFBr. The LET can be determined from the luminescence ratio between Eu:BaFBr and BGO, and the dosimeter response can be corrected. We evaluated the LET dependence of the luminescence efficiency of the BGO and Eu:BaFBr as the quenching effect. We propose and discuss the correction of the quenching effect using the signal intensity ratio of the both materials. Although the correction precision is not sufficient, feasibility of the proposed correction method is proved through basic experiments.

  3. A dual-stimuli-responsive fluorescent switch ultrathin film

    Science.gov (United States)

    Li, Zhixiong; Liang, Ruizheng; Liu, Wendi; Yan, Dongpeng; Wei, Min

    2015-10-01

    Stimuli-responsive fluorescent switches have shown broad applications in optical devices, biological materials and intelligent responses. Herein, we describe the design and fabrication of a dual-stimuli-responsive fluorescent switch ultrathin film (UTF) via a three-step layer-by-layer (LBL) technique: (i) encapsulation of spiropyran (SP) within an amphiphilic block copolymer (PTBEM) to give the (SP@PTBEM) micelle; (ii) the mixture of riboflavin (Rf) and poly(styrene 4-sulfonate) (PSS) to enhance the adhesion ability of small molecules; (iii) assembly of negatively charged SP@PTBEM and Rf-PSS with cationic layered double hydroxide (LDH) nanoplatelets to obtain the (Rf-PSS/LDH/SP@PTBEM)n UTFs (n: bilayer number). The assembly process of the UTFs and their luminescence properties, as monitored by fluorescence spectroscopy and scanning electron microscopy (SEM), present a uniform and ordered layered structure with stepwise growth. The resulting Rf-PSS/LDH/SP@PTBEM UTF serves as a three-state switchable multicolor (green, yellow, and red) luminescent system based on stimulation from UV/Vis light and pH, with an acceptable reversibility. Therefore, this work provides a facile way to fabricate stimuli-responsive solid-state film switches with tunable-color luminescence, which have potential applications in the areas of displays, sensors, and rewritable optical memory and fluorescent logic devices.Stimuli-responsive fluorescent switches have shown broad applications in optical devices, biological materials and intelligent responses. Herein, we describe the design and fabrication of a dual-stimuli-responsive fluorescent switch ultrathin film (UTF) via a three-step layer-by-layer (LBL) technique: (i) encapsulation of spiropyran (SP) within an amphiphilic block copolymer (PTBEM) to give the (SP@PTBEM) micelle; (ii) the mixture of riboflavin (Rf) and poly(styrene 4-sulfonate) (PSS) to enhance the adhesion ability of small molecules; (iii) assembly of negatively charged SP

  4. Alcohol solutions of triphenyl-tetrazolium chloride as high-dose radiochromic dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Kovacs, A.; Wojnarovits, L.; El-Assy, N.B.; Afeefy, H.Y.; Al-Sheikhly, M.; Walker, M.L.; McLaughlin, W.L. [National Inst. of Standards and Technology (NML), Gaithersburg, MD (United States). Ionizing Radiation Div.

    1995-10-01

    The radiolytic reduction of colorless tetrazolium salts in aqueous solution to the highly colored formazan dye is a well-known acid-forming radiation chemical reaction. Radiochromic thin films and three-dimensional hydrocolloid gels have been used for imaging and mapping absorbed dose distributions. The high solubility of 2,3,5-triphenyl-tetrazolium chloride (TTC) in alcohols provides a useful liquid dosimeter (45 mM TTC in aerated ethanol) and shows a linear response of absorbance increase ({lambda}{sub max} = 480 nm) with dose over the range 1-16 kGy. The linear molar absorption coefficient ({epsilon}{sub m}) for the formazan at the absorption peak is 1.5 x 10{sup 3} m{sup 2} mol{sup -1}, and the radiation chemical yield for the above solution is G (formazan) 0.014 {mu}mol J{sup -1}. The irradiation temperature coefficient is about 0.8 percent per degree Celsius rise in temperature over the temperature range 0-30 {sup o}C but is much larger between 30{sup o} and 60 {sup o}C. The unirradiated and irradiated solutions are stable over at least five days storage at normal laboratory temperature in the dark, but when stored in daylight at elevated temperature, the unirradiated solution in sealed amber glass ampoules undergoes slow photolytic dye formation, and the irradiated solution experiences initial fading and subsequent reversal (photochromism) when exposed to direct sunlight. (author).

  5. In situ ion-beam-induced luminescence analysis for evaluating a micrometer-scale radio-photoluminescence glass dosimeter

    Science.gov (United States)

    Kawabata, Shunsuke; Kada, Wataru; Parajuli, Raj Kumar; Matsubara, Yoshinori; Sakai, Makoto; Miura, Kenta; Satoh, Takahiro; Koka, Masashi; Yamada, Naoto; Kamiya, Tomihiro; Hanaizumi, Osamu

    2016-06-01

    Micrometer-scale responses of radio-photoluminescence (RPL) glass dosimeters to focused ionized particle radiation were evaluated by combining ion-beam-induced luminescence (IBIL) and proton beam writing (PBW) using a 3 MeV focused proton microbeam. RPL phosphate glass dosimeters doped with ionic Ag or Cu activators at concentrations of 0.2 and 0.1% were fabricated, and their scintillation intensities were evaluated by IBIL spectroscopy under a PBW micropatterning condition. Compared with the Ag-doped dosimeter, the Cu-doped dosimeter was more tolerant of the radiation, while the peak intensity of its luminescence was lower, under the precise dose control of the proton microprobe. Proton-irradiated areas were successfully recorded using these dosimeters and their RPL centers were visualized under 375 nm ultraviolet light. The reproduction of the irradiated region by post-RPL imaging suggests that precise estimation of irradiation dose using microdosimeters can be accomplished by optimizing RPL glass dosimeters for various proton microprobe applications in organic material analysis and in micrometer-scale material modifications.

  6. A comparison of the dosimetric characteristics of a glass rod dosimeter and a thermoluminescent dosimeter for mailed dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Rah, Jeong-Eun [Department of Biomedical Engineering, Catholic University of Korea, College of Medicine, Seoul (Korea, Republic of); Research Institute of Biomedical Engineering, Catholic University of Korea, Seoul (Korea, Republic of); Hong, Ju-Young [Department of Radiation Oncology, Kangnam St. Mary' s Hospital, College of Medicine, Catholic University of Korea, Seoul (Korea, Republic of); Kim, Gwe-Ya [Department of Radiation Oncology, Austin Caner Centers, Austin, TX (United States); Kim, Yon-Lae [Department of Radiation Oncology, Konkuk University Hospital, Seoul (Korea, Republic of); Shin, Dong-Oh [Department of Radiation Oncology, Kyung Hee University, School of Medicine, Seoul (Korea, Republic of); Suh, Tae-Suk [Department of Biomedical Engineering, Catholic University of Korea, College of Medicine, Seoul (Korea, Republic of); Research Institute of Biomedical Engineering, Catholic University of Korea, Seoul (Korea, Republic of)], E-mail: suhsanta@catholic.ac.kr

    2009-01-15

    A radiophotoluminescent glass rod dosimeter (RPL-GRD) system has recently become commercially available. The purpose of this study was to investigate the dosimetric characteristics (reproducibility, linearity, fading, energy dependence and angular dependence) of the RPL-GRD for a mailed dosimeter and to compare it with LiF-TLD powder. In this study, the model GD-301 GRD and TLD-700 were powder type used. All measurements with the exception of angular dependence were performed in a water phantom using a holder stand. The RPL-GRD has better reproducibility than the TLD for the Co-60 beam as well as for the clinical photon beam. The RPL-GRD signal was linear as a function of applied dose in the range of 0.5-3 Gy for the Co-60 gamma rays. The fading of the RPL-GRD after a received dose of 2 Gy was initially found to be within 1.7% for five months. The energy dependence of both dosimeters was found to be less than 1.6% for photon beams, but was less than 5.0% for electron beams, which was in agreement with published data. The angular dependence of the RPL-GRD was measured to be approximately 1.4% for angles ranging {+-}90 deg. from the beam axis using a spherical polystyrene phantom. The measurements comparing RPL-GRD and TLD dosimetric characteristics demonstrated that the RPL-GRD is suitable for mailed dosimetry in a quality assurance (QA) audit program.

  7. A small animal image guided irradiation system study using 3D dosimeters

    Science.gov (United States)

    Qian, Xin; Admovics, John; Wuu, Cheng-Shie

    2015-01-01

    In a high resolution image-guided small animal irradiation platform, a cone beam computed tomography (CBCT) is integrated with an irradiation unit for precise targeting. Precise quality assurance is essential for both imaging and irradiation components. The conventional commissioning techniques with films face major challenges due to alignment uncertainty and labour intensive film preparation and scanning. In addition, due to the novel design of this platform the mouse stage rotation for CBCT imaging is perpendicular to the gantry rotation for irradiation. Because these two rotations are associated with different mechanical systems, discrepancy between rotation isocenters exists. In order to deliver x-ray precisely, it is essential to verify coincidence of the imaging and the irradiation isocenters. A 3D PRESAGE dosimeter can provide an excellent tool for checking dosimetry and verifying coincidence of irradiation and imaging coordinates in one system. Dosimetric measurements were performed to obtain beam profiles and percent depth dose (PDD). Isocentricity and coincidence of the mouse stage and gantry rotations were evaluated with starshots acquired using PRESAGE dosimeters. A single PRESAGE dosimeter can provide 3 -D information in both geometric and dosimetric uncertainty, which is crucial for translational studies.

  8. Radiation-induced defects in magnesium lactate as ESR dosimeter

    CERN Document Server

    Hassan, G M; Takaki, S

    1999-01-01

    Magnesium lactate (Mg-lactate: (CH sub 3 CH(OH)COO) sub 2 Mg), magnesium lactate doped with lithium lactate (Mg(Li)-lactate) and nominal pure lithium lactate (CH sub 3 CH(OH)COOLi) doped with Mg-lactate (Li(Mg)-lactate) were irradiated by gamma-rays to study radicals for materials of radiation dosimeter with electron spin resonance (ESR). Quartet spectra were ascribed to lactate radicals in Mg-lactate and Li(Mg)-lactate with the spectroscopic splitting factors (g-factor) of 2.0032+-0.004 and 2.0029+-0.004 and the intensity ratio of 1:3:3:1 due to the hyperfine coupling constants of (A/g beta) of 1.92+-0.06 and 1.82+-0.06 mT, respectively. The response to gamma-ray dose and the thermal stability as well as the effect of UV-illumination have been studied to establish this material as an ESR dosimeter. The number of free radicals per 100 eV (G-value) was obtained to be 1.15+-0.32, 1.35+-0.35, 0.46+-0.14 and 0.78+-0.24 for Mg-lactate, Mg(Li)-lactate, Li-lactate and Lie(Mg)-lactate, respectively. Thermoluminescenc...

  9. Physico-chemical studies for strontium sulfate radiation dosimeter

    Directory of Open Access Journals (Sweden)

    M.A.H. Rushdi

    2015-04-01

    Full Text Available Anhydrous strontium sulfate (SrSO4 has shown a promise candidate as a dosimeter for low dose applications producing unique EPR signals with γ-rays which it has a linear response relationship (r2 = 0.999 in the range of 1–100 Gy. The present study extended to evaluate the properties of strontium sulfate dosimeter in intermediate dose range of technology applications. It was observed that the intensity of the EPR signal at g = 2.01081 increases with a 3rd polynomial function in the range of 0.10–15 kGy. In addition, the radical (SO4− provides a stable signal with a good reproducibility (0.107%. Other physics characteristic including the collision of mass stopping power dependence of the system and the effect of atomic number in different energy regions were investigated. The uncertainty budget for high doses has obtained from the measurement with value of 3.57% at 2σ confidence level.

  10. Optical Fibre Dosimeter for SASE FEL Undulators

    CERN Document Server

    Körfer, M

    2003-01-01

    Single pass Free Electron Lasers (FELs) based on self-amplified spontaneous emission (SASE) are developed for high brightness and short wavelength applications. They use permanent magnet undulators which are radiation sensitive devices. During accelerator commissioning beam losses can appear anywhere along the undulator line. To avoid damage of the permanent magnets due to radiation, an optical fibre dosimeter system can be used. The increase of absorption caused by ionizing radiation is measured in radiation sensitive optical fibers. The dose system enables relatively fast particle loss tuning during accelerator operation and allows the monitoring of the accumulated dose. Dose measurements in narrow gaps which are inaccessible for any other (online) dosimeter type become possible. The electromagnetic insensitivity of optical fibre sensor is an advantage of applications in strong magnetic undulator fields. At each location the light absorption is measured by using an optical power-meter. The dynamic range is ...

  11. Characteristics of polyacrylamide gel with THPC and Turnbull Blue gel dosimeters evaluated using optical tomography

    Science.gov (United States)

    Pilařová (Vávrů), Kateřina; Kozubíková, Petra; Šolc, Jaroslav; Spěváček, Václav

    2014-11-01

    The purpose of this study was to compare characteristics of radiochromic gel - Turnbull Blue gel (TB gel) with polymer gel - polyacrylamide gel and tetrakis hydroxymethyl phosphonium chloride (PAGAT) using optical tomography. Both types of gels were examined in terms of dose sensitivity, dose response linearity and background value of spectrophotometric absorbance. The calibration curve was obtained for 60Co irradiation performed on Gammacell 220 at predefined gamma dose levels between 0 and 140 Gy for TBG and 0-15 Gy for PAGAT. To measure relative dose distributions from stereotactic irradiation, dosimeters were irradiated on Leksell Gamma Knife Perfexion. The cylindrical glass housings filled with gel were attached to the stereotactic frame. They were exposed with single shot and 16 mm collimator by 65 Gy to a 50% prescription isodose for TB gel and 4 Gy to a 50% prescription isodose for PAGAT. Evaluations of dosimeters were performed on an UV-vis Spectrophotometer Helios β and an optical cone beam homemade tomography scanner with a 16-bit astronomy CCD camera with a set of color filters. The advantages and potential disadvantages for both types of gel dosimeters were summarized. Dose distribution in central slice and measured profiles of 16 mm shot shows excellent correspondence with treatment planning system Leksell GammaPlan® for both PAGAT and Turnbull Blue gels. Gel dosimeters are suitable for steep dose gradient verification. An optical tomography evaluation method is successful. Dose response characteristics of TB gel and PAGAT gel are presented.

  12. Picosecond Photovoltaic Response in Tilted Lanthanum Doped Manganite Films

    Directory of Open Access Journals (Sweden)

    Zhiqing Lu

    2013-01-01

    Full Text Available Anisotropic picosecond photovoltaic responses were observed in lanthanum doped manganite LaxCa1-xMnO3 (x=0.67 and 0.4 thin films, which were deposited on miscut LaSrAlO4 substrates under ultraviolet pulsed laser irradiation without external bias. The 10%–90% rise time and the full width at half maximum of La0.67Ca0.33MnO3 were 470 and 585 ps, respectively, and those of La0.4Ca0.6MnO3 were 220 and 515 ps. The photovoltage sensitivities of La0.67Ca0.33MnO3 and La0.4Ca0.6MnO3, which are sensitive to the concentrations of lanthanum of the samples, are 0.28 V/mJ and 3.47 V/mJ, respectively. The photosensitivity in the films deposited on MgO is higher than that in those deposited on LaSrAlO4 substrates, for it has a big lattice mismatch. These results should open a route for the application of lanthanum doped manganite as an ultrafast photodetector material.

  13. SU-E-T-386: Evaluation of EBT3 Film Response in Different Batches

    Energy Technology Data Exchange (ETDEWEB)

    Escarcia, F [Universidad Nacional Autonoma de Mexico, Mexico Df, DF (Mexico); Herrera, J; Garcia, O [Instituto Nacional de Neurologia y Neurocirugia, Mexico Df, DF (Mexico)

    2015-06-15

    Purpose: To investigate the uniformity of film response of EBT3 film of two different film batches. It has been reported that the response of the EBT film family is not homogenous between film batches. The later may have an impact in the dosimetry of small radiotherapy beams. Methods: A solid water phantom was used for dosimetric measurements. EBT3 film irradiation was performed with a 6 MV photon beam at 5 cm depth with a SAD of 100 cm. All irradiations were performed perpendicularly to the film plane covering the dose range 1 to 10 Gy. Three square field sizes were used to analyze the film response energy dependence: 10, 5 and 1 cm{sup 2}. Two batches of film EBT3 were used #A03181302 (B1) and #03031403 (B2). Film read out was carrying out with an Epson Perfection V750-Pro flatbed scanner in transmission mode with a spatial resolution of 72 dpi, with all post-processing and colour management options turned off, using 48 bits RGB colour depth. The scans were analyzed with the red channel. Results: The results shown that there were differences between the film response for each batch. The differences between batches for 1 Gy were 2%, 6% and 12% for 10, 5 and 1 cm2 square field sizes, respectively. The differences found for 10 Gy were 13%, 14% and 13% for 10, 5 and 1 cm{sup 2} square field sizes, respectively. It can be observed that the dependence with field size dismissed for higher doses. The later may be due to film response saturation at 10 Gy. Conclusion: The EBT3 film -as its predecessors-, it suffer for inter-batch variability in the film response. Further research is required to assess the possible impact in small beam dosimetry.

  14. Fluorescent diazapyrenium films and their response to dopamine.

    Science.gov (United States)

    Cejas, Mabel A; Raymo, Françisco M

    2005-06-21

    Experimental protocols for the preparation of 2,7-diazapyrenium films on glass, quartz, and silica in one or two steps have been developed. The one-step procedures involve the adsorption of preformed 2,7-diazapyrenium dications with trimethoxysilane appendages to the hydroxylated substrates. The two-step procedures consist in the formation of interfacial polysiloxanes with pendent chloromethyl groups and their subsequent coupling to monoalkylated 2,7-diazapyrene derivatives. For the modification of the glass slides, the silane building blocks have been copolymerized with Si(OEt)4. The transmission absorption spectra of the coated glass and quartz slides all reveal the characteristic bands of the 2,7-diazapyrenium chromophores. Combustion analyses confirm the adsorption of the 2,7-diazapyrenium dications on the silica particles. A comparison of the surface coverages of all films indicates that the one-step procedures are significantly more efficient than their two-step counterparts. Furthermore, the copolymerization of the silane building blocks with Si(OEt)4 translates into an increase in 2,7-diazapyrenium surface coverage of approximately 1 order of magnitude. The emission and excitation spectra of all modified substrates reveal the characteristic bands of the 2,7-diazapyrenium fluorophores. The fluorescence quantum yield, however, decreases as the surface coverage increases. Presumably, interactions between adjacent fluorophores encourage nonradiative deactivation pathways. With the exception of the glass slides modified in two steps, all films respond to the presence of dopamine, in aqueous environments at neutral pH, with pronounced decreases in emission intensity. The association of the 2,7-diazapyrenium acceptors and dopamine donors at the solid/liquid interface is responsible for fluorescence quenching. The glass slides and silica particles modified in one step are the most sensitive substrates and respond to sub-millimolar concentrations of dopamine with

  15. Dosimetric characteristics of a radiochromic polyvinyl butyral film containing 2,4-hexadiyn-1,6-bis(n-butyl urethane).

    Science.gov (United States)

    Abdel-Fattah, A A; Soliman, Y S; Bayomi, A M M; Abdel-Khalek, A A

    2014-04-01

    A radiation-sensitive compound 2,4-hexadiyn-1,6-bis(n-butyl urethane) (HDDBU) was synthesized, characterized by FTIR spectroscopy, and introduced into a thin polyvinyl butyral film to form a radiation dosimeter for industrial irradiation facilities. The monomer polymerizes under gamma radiation, inducing change in the film spectrum in the range of 200-400 nm. According to XRD spectroscopy, the film contains monomeric HDDBU in a non-crystalline state. The dose response function, radiation sensitivity, and dependences of the response on environmental factors were studied. Uncertainty of dose measurements with the proposed dosimetry system was analyzed in detail.

  16. SU-E-T-171: Characterization of the New Xoft Axxent Electronic Brachytherapy Source Using PRESAGE Dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Steinmann, A; Followill, D; Ibbott, G [UT MD Anderson Cancer Center, Houston, TX (United States); Adamovics, J [John Adamovics, Skillman, NJ (United States)

    2015-06-15

    Purpose: To characterize the Xoft Axxent electronic brachytherapy source using PRESAGE™ dosimeters to obtain independent confirmation of TG-43U1 dosimetry values from previous studies and ascertain its reproducibility in HDR brachytherapy. Methods: PRESAGE™ dosimeters are solid, polyurethane-based dosimeters doped with radiochromic leucodyes that produce a linear optical-density response when exposed to radiation. Eight 1-kg dosimeters were scanned prior to irradiation on an optical-CT scanner to eliminate background signal and any optical imperfections from each dosimeter. To quantify potential imaging artifacts due to oversaturated responses in the immediate range of the source, half of the eight dosimeters were cast with a smaller channel diameter of 5.4 mm, and the other half were cast with a larger channel diameter of 15mm. During irradiation, the catheters were placed in the center of each channel. Catheters fit the 5.4mm diameters channels whereas polyurethane plugs were inserted into the larger channels to create a sturdy, immobile catheter which allowed uniform dose distributions. Two dosimeters of each 5.4mm and 15mm were irradiated at either 1517.3 cGy or 2017.5 cGy. Post-irradiation scans were performed within 48 hours of irradiation. A 3D reconstruction based on subtraction of these two images and the relative dose measurements were made using in-house software. Results: Comparing measured radial dose rates with previous results revealed smaller percent errors when PRESAGE™ irradiations were at lower maximum dose. The dosimeters showed small deviations in radial dose function, g{sub p} (r), from previous studies. Among the dosimeters irradiated at 1517.3 cGy, the g{sub p}(r) compared to previous studies fluctuated from 0.0043 to 0.3922. This suggests small fluctuations can drastically change radial dose calculations. Conclusion: The subtraction of pre-irradiation and post-irradiation scans of PRESAGE™ dosimeters using an optical-CT scanner

  17. Development of semiconductor radiation sensors for portable alarm-dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y. K.; Moon, B. S.; Chung, C. E.; Hong, S. B.; Kim, J. Y.; Kim, J. B.; Han, S. H.; Lee, W. G. [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2001-01-01

    We studied Semiconductor Radiation Sensors for Portable Alarm-Dosimeter. We calculated response functions for gamma energy 0.021, 0.122, 0.662, 0.835, 1.2 MeV using EGS4 codes. When we measured at various distance from source to detector, the detection efficiency of Si semiconductor detector was better than that of GM tube. The linear absorption coefficients of steel and aluminum plate were measured. These experimental results of the response of detector for intensity of radiation field coincide to the theoretical expectation. The count value of Si detector was changed with changing thickness of steel as changing threshold voltage of discriminator, and the linear absorption coefficient increased with increasing threshold voltage. Radiation detection efficiency shows difference at each threshold voltage condition. This results coincided to the theoretical simulation. 33 refs., 27 figs., 8 tabs. (Author)

  18. Standard Procedure for Calibrating an Areal Calorimetry Based Dosimeter

    Science.gov (United States)

    2015-05-01

    2015 AFRL-RH-FS-TR-2015-0013 Standard Procedure for Calibrating an Areal Calorimetry Based Dosimeter Charles W. Beason Devon Ryan...0013 "Standard Procedure for Calibrating an Areal Calorimetry Based Dosimeter" TR LELAND JOHNSON, DR-III, DAF Contract Monitor Radio Frequency...Calibrating an Areal Calorimetry Based Dosimeter 5b. GRANT NUMBER N/A 5c. PROGRAM ELEMENT NUMBER 62202F 6. AUTHOR(S) 5d. PROJECT NUMBER N/A Charles W

  19. Reactor Gamma Heat Measurements with Calorimeters and Thermoluminescence Dosimeters

    DEFF Research Database (Denmark)

    Haack, Karsten; Majborn, Benny

    1973-01-01

    Intercomparison measurements of reactor γ-ray heating were carried out with calorimeters and thermoluminescence dosimeters. Within the measurement uncertainties the two methods yield coincident results. In the actual measurement range thermoluminescence dosimeters are less accurate than calorimet...... calorimeters, but possess advantages such as a small probe size and the possibility of making simultaneous measurements at many different positions. Hence, thermoluminescence dosimeters may constitute a valuable supplement to calorimeters for reactor γ-ray heating measurements....

  20. Comparison of the fiber optic dosimeter and semiconductor dosimeter for use in diagnostic radiology

    Science.gov (United States)

    Yoo, W. J.; Shin, S. H.; Sim, H. I.; Hong, S.; Kim, S. G.; Jang, J. S.; Kim, J. S.; Jeon, H. S.; Kwon, G. W.; Jang, K. W.; Cho, S.; Lee, B.

    2014-05-01

    A fiber-optic dosimeter (FOD) was fabricated using a plstic scintillating fiber, a plastic optical fiber, and a multi-pixel photon counter to measure entrance surface dose (ESD) in diagnostic radiology. Under changing tube current and irradition time of the digital radiography (DR) system, we measured the scintillating light and the ESD simultaneously. As experiemtnal results, the total counts of the FOD were changed in a manner similar to the ESDs of the semiconductor dosimeter (SCD). In conclusion, we demonstrated that the proposed FOD minimally affected the diagnostic information of DR image while the SCD caused serious image artifacts.

  1. Turnbull Blue Gel (TBG) evaluation as optical dosimeter

    Science.gov (United States)

    Borguezan Neto, E.; Batistuti, M. R.; Pavoni, J. F.; Bachmann, L.

    2017-05-01

    The radiochromic Turnbull Blue Gel (TBG) is sensitive to X- and γ-rays. When exposed to high-energy radiation, TBG can simulate biological tissues, so this gel has potential use in ionizing radiation dosimetry. After irradiation, the yellow TBG changes to the blue Turnbull Blue dye. This work aims to evaluate how TBG responds to exposure to ultraviolet, visible, and infrared radiation from the sun. The gel was irradiated with a solar simulator, which sensitized TBG and transformed it into the Turnbull Blue dye; a change in the optical absorption ensued. The fluence values delivered by the source did not provide a linear response, but it was still possible to use TBG as an optical dosimeter. In conclusion, TBG can be applied to detect solar radiation because it is sensitive enough to measure sun exposure values at time intervals of few minutes.

  2. Durability patch and damage dosimeter: a portable battery-powered data acquisition computer and durability patch design process

    Science.gov (United States)

    Haugse, Eric D.; Johnson, Patrick E.; Smith, David L.; Rogers, Lynn C.

    2000-05-01

    Repairs of secondary structure can be accomplished by restoring structural integrity at the damaged area and increasing the structure's damping in the repair region. Increased damping leads to a reduction in resonant response and a repair that will survive for the life of the aircraft. In order to design a repair with effective damping properties, the in-service structural strains and temperatures must be known. A rugged, small and lightweight data acquisition unit called the Damage Dosimeter has been developed to accomplish this task with minimal impact to the aircraft system. Running autonomously off of battery power, the Damage Dosimeter measures three channels of strain at sample rates as high as 15 kilo-samples per second and a single channel of temperature. It merges the functionality of both analog signal conditioning and a digital single board computer on one 3.5 by 5 inch card. The Damage Dosimeter allows an engineer to easily instrument an in-service aircraft to assess the structural response characteristics necessary to properly select damping materials. This information in conjunction with analysis and design procedures can be used to design a repair with optimum effectiveness. This paper will present the motivation behind the development of the Damage Dosimeter along with an overview of its functional capabilities and design. In-service flight data and analysis results will be discussed for two applications. The paper will also describe how the Damage Dosimeter is used to enable the Durability Patch design process.

  3. A cyanocobalamin dosimeter for monitoring gamma-radiation doses of 0.1-2 kGy

    Science.gov (United States)

    Maged, A. F.; Hamza, M. S. A.; Saad, E. A.

    1997-08-01

    A simple dosimeter is described for measuring gamma-ray doses useful for insect sterilization, seed-sprouting inhibition and food shelf-life extensions. The red aqueous solution of cyanocobalamin (B 12) before irradiation, assumes a stable yellow color when irradiated. It shows a linear response of absorbance decrease with the dose over the range of 0.1-2.0 kGy when the concentration of cyanocobalamin is equal 0.09 mM. The radiation-induced color is analyzed spectrophotometrically at the maximum absorption band (361 nm). The absorption spectra, dose response and post-irradiation stability of the dosimeter are discussed.

  4. A cyanocobalamin dosimeter for monitoring gamma-radiation doses of 0.1-2 kGy

    Energy Technology Data Exchange (ETDEWEB)

    Maged, A.F. [National Centre for Radiation Research and Technology, Cairo (Egypt); Hamza, M.S.A.; Saad, E.A. [Ain Shams Univ., Cairo (Egypt). Faculty of Science

    1997-08-01

    A simple dosimeter is described for measuring gamma-ray doses useful for insect sterilization, seed-sprouting inhibition and food shelf-life extension. The red aqueous solution of cyanocobalamin (B{sub 12}) before irradiation, assumes a stable yellow color when irradiated. It shows a linear response of absorbance decrease with the dose over the rage of 0.1-2.0 kGy when the concentration of cyanocobalamin is equal 0.09 mM. The radiation-induced color is analyzed spectrophotometrically at the maximum absorption band (361 nm). The absorption spectra, dose response and post-irradiation stability of the dosimeter are discussed. (author).

  5. Technical Note: On GAFChromic EBT-XD film and the lateral response artifact.

    Science.gov (United States)

    Lewis, David F; Chan, Maria F

    2016-02-01

    The new radiochromic film, GAFChromic EBT-XD, contains the same active material, lithium-10,12-pentacosadiynoate, as GAFChromic EBT3, but the crystalline form is different. This work investigates the effect of this change on the well-known lateral response artifact when EBT-XD film is digitized on a flatbed scanner. The dose response of a single production lot of EBT-XD was characterized by scanning an unexposed film plus a set of films exposed to doses between 2.5 and 50 Gy using 6 MV photons. To characterize the lateral response artifact, the authors used the unexposed film plus a subset of samples exposed to doses between 20 and 50 Gy. Digital images of these films were acquired at seven discrete lateral locations perpendicular to the scan direction on three Epson 10000XL scanners. Using measurements at the discrete lateral positions, the scanner responses were determined as a function of the lateral position of the film. From the data for each scanner, a set of coefficients were derived whereby measured response values could be corrected to remove the effects of the lateral response artifact. The EBT-XD data were analyzed as in their previous work and compared to results reported for EBT3 in that paper. For films scanned in the same orientation and having equal responses, the authors found that the lateral response artifact for EBT-XD and EBT3 films was remarkably similar. For both films, the artifact increases with increased net response. However, as EBT-XD is less sensitive than EBT3, a greater exposure dose is required to reach the same net response. On this basis, the lower sensitivity of EBT-XD relative to EBT3 results in less net response change for equal exposure and a reduction in the impact of the lateral response artifact. The shape of the crystalline active component in EBT-XD and EBT3 does not affect the fundamental existence of the lateral response artifact when the films are digitized on flatbed scanners. Owing its lower sensitivity, EBT-XD film

  6. Phosphate Glass Gamma-Radiation Dosimeter

    Science.gov (United States)

    1952-11-30

    JH Section 3F» 3he PluftXmafoSEP 3 illM^An «ft*i tiöu« Plate 1 Shows the appearance of the !?P-60(XN-»3)/H) dosimeter, or radiac detector...200 r and MB! RESTRICTED FyT^&jw^* ^XJ^ WWW^^S^*^?^^?^’ ’:myv) f’Ol.ArO!»’« rOf.f’. JhV fiOll HI.V-fc "• KCH ÜfPARTMFMT RESTRICTED -56- The

  7. Personnel exposure control system with auto thermoluminescence dosimeter in Shimane Nuclear Power Station

    Energy Technology Data Exchange (ETDEWEB)

    Matsubayashi, Hideo; Ochi, Susumu (Chugoku Electric Power Co. Inc., Hiroshima (Japan))

    1982-03-01

    In the past, film badges and pocket dosimeters were put on the persons who entered a controlled area in a nuclear power station to measure the external radiation exposure. For these, read out error or mistake, delay in taking out the result, trouble for monitoring many persons, etc. were problems. To solve these problems, the auto thermoluminescence dosimeter (ATLD) system has been introduced in Shimane Nuclear Power Station in place of pocket dosimeters since the second half of fiscal 1978. The outline of the system and the composition and software of the TLD automatic readout system are described. For the control of access to controlled areas, workers are forced to pass the check point where watchmen check everyone's ID card, and subjected to the check-up with the TLD automatic readout device. The checking items in the case of entering the areas are: (1) confirmation of licensee, (2) confirmation of the term of validity for the medical examination on ionizing radiation, (3) checking for exposure dose compared to the controlled exposure level, (4) confirmation of time limit to stay in controlled areas, and (5) TLD element annealing condition. The checking items in the case of leaving the areas are: (1) checking for identifying the TLD element that the personnel has brought in, (2) exposure dose compared to the controlled exposure level, (3) time for which the personnel stayed in controlled areas.

  8. Numerical Analysis of Transient Temperature Response of Soap Film

    Science.gov (United States)

    Tanaka, Seiichi; Tatesaku, Akihiro; Dantsuka, Yuki; Fujiwara, Seiji; Kunimine, Kanji

    2015-11-01

    Measurements of thermophysical properties of thin liquid films are important to understand interfacial phenomena due to film structures composed of amphiphilic molecules in soap film, phospholipid bilayer of biological cell and emulsion. A transient hot-wire technique for liquid films less than 1 \\upmu m thick such as soap film has been proposed to measure the thermal conductivity and diffusivity simultaneously. Two-dimensional heat conduction equations for a solid cylinder with a liquid film have been solved numerically. The temperature of a thin wire with liquid film increases steeply with its own heat generation. The feasibility of this technique is verified through numerical experiments for various thermal conductivities, diffusivities, and film thicknesses. Calculated results indicate that the increase in the volumetric average temperature of the thin wire sufficiently varies with the change of thermal conductivity and diffusivity of the soap film. Therefore, the temperature characteristics could be utilized to evaluate both the thermal conductivity and diffusivity using the Gauss-Newton method.

  9. CCD imaging for optical tomography of gel radiation dosimeters.

    Science.gov (United States)

    Wolodzko, J G; Marsden, C; Appleby, A

    1999-11-01

    are compared. The correlation coefficients obtained are typically on the order of 0.98, and the p value from analysis of variance is approximately 0.05, indicating a linear and reproducible response for the dosimeter formulation and imaging system.

  10. A quantum size effect in infrared optical response of aliminum thin films

    Science.gov (United States)

    Xiao, Mufei; Villagómez, Ricardo

    1998-03-01

    We present a quantum mechanical calculation for diamagnetic optical response of metallic thin films. The study shows that in the optical response of the thin films, such as the reflectance, there exists an oscillatory dependence on the film thickness when the film contents less than about 100 monolayers, and the period of the oscillation corresponds to one or few monolayers. We show that the oscillation can be attributed to the intraband fluctuations of the valence electrons at discrete energy states as well as at continuum energy states. For comparison, we present some experimental results for Aluminum thin films of thickness 5 ~112ÅInfrared (λ=9.2μ m) optical reflectance of the films was measured, which demonstrates experimentally the predicted oscillating fine structures.

  11. A stimuli-responsive and bioactive film based on blended polyvinyl alcohol and cashew gum polysaccharide.

    Science.gov (United States)

    Silva, Fábio E F; Batista, Karla A; Di-Medeiros, Maria C B; Silva, Cassio N S; Moreira, Bruna R; Fernandes, Kátia F

    2016-01-01

    In this study, a stimuli-responsive, biodegradable and bioactive film was produced by blending cashew gum polysaccharide (CGP) and polyvinyl alcohol (PVA). The film presented malleability and mechanical properties enabling an easy handling. Wetting the film changed the optical property from opacity to levels of transparency higher than 70% and resulted in up to 2-fold increase in its superficial area. Different swelling indexes were obtained varying the pH of solvent, which allows classifying the CGP/PVA film as pH sensitive stimuli-responsive material. The bioactivity was achieved through covalent immobilization of papain, which remained active after storage of CGP/PVA-papain film for 24h in the presence of buffer or in a dry form. These results evidenced that CGP/PVA-papain film is a very promising material for biomedical applications.

  12. Influence of films thickness and structure on the photo-response of ZnO films

    Science.gov (United States)

    Ali Yıldırım, M.; Ateş, Aytunç

    2010-04-01

    ZnO thin films were grown using Successive Ionic Layer Adsorption and Reaction (SILAR) method on glass substrates at room temperature. Annealing temperatures and film thickness effect on the structural, morphological, optical and electrical properties of the films were studied. For this as-deposited films were annealed at 200, 300, 400 and 500 °C for 30 min in oxygen atmosphere. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies showed that the films are covered well with glass substrates and have good polycrystalline structure and crystalline levels. The film thickness effect on band gap values was investigated and band gap values were found to be within the range of 3.49-3.19 eV. The annealing temperature and light effect on electrical properties of the films were investigated and it was found that the current increased with increasing light intensity. The resistivity values were found as 10 5 Ω-cm for as-deposited films from electrical measurements. The resistivity decreased decuple with annealing temperature and decreased centuple with light emission for annealed films.

  13. Aerosol deposition in automatic dosimeter nebulization

    Energy Technology Data Exchange (ETDEWEB)

    Nieminen, M.M.; Lahdensuo, A.; Muittari, A.; Holli, H.; Karvonen, J.

    1987-01-01

    A new dosimeter nebulization method was studied in 10 asthmatics and 8 normal volunteers by delivering fixed doses of /sup 99m/Tc-traced radioaerosol in 0.2 s periods of tidal breathing. Two separate inspiratory phases were studied with the onset of nebulization, when in the earlier phase 15% and in the later phase 60% of tidal volume was inhaled. Further, bronchodilator administration was analogically assessed in the asthmatics. In healthy subjects, the total lung deposition was 17% greater in the earlier phase (P<0.005) than in the later one. In asthmatics, the difference was not significant. The losses of aerosol outside the lower respiratory tract were minimized, in the mouthwashing 0.3% and in the exhaled air 1.4%. The onset of nebulization (early or late) had no significant effect on bronchodilation with salbutamol in asthmatics. We conclude that the present dosimeter method is useful for efficient delivery of radioaerosols and drugs, and for standardization of bronchoprovocation.

  14. Local Electrical Response in Alkaline-Doped Electrodeposited CuInSe2/Cu Films

    Directory of Open Access Journals (Sweden)

    Javier A. Barón-Miranda

    2016-12-01

    Full Text Available The local electrical response in alkaline-doped CuInSe2 films prepared by single-step electrodeposition onto Cu substrates was studied by current-sensing atomic force microscopy. The CuInSe2 (CIS films were prepared from single baths containing the dopant ions (Li, Na, K or Cs and were studied by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and photocurrent response. Increased crystallinity and surface texturing as the ion size increased were observed, as well as an enhanced photocurrent response in Cs-doped CIS. Li- and Na-doped films had larger conductivity than the undoped film while the K- and Cs-doped samples displayed shorter currents and the current images indicated strong charge accumulation in the K- and Cs-doped films, forming surface capacitors. Corrected current-sensing AFM IV curves were adjusted with the Shockley equation.

  15. The behaviour of alanine dosimeters at temperatures between 100 and 300 K

    Energy Technology Data Exchange (ETDEWEB)

    Sharpe, P.H.G. [National Physical Laboratory, Teddington TW11 0LW (United Kingdom)], E-mail: peter.sharpe@npl.co.uk; Sephton, J.P.; Gouldstone, C.A. [National Physical Laboratory, Teddington TW11 0LW (United Kingdom)

    2009-07-15

    A cryostat has been constructed to enable irradiations in a MDS Nordion Gammacell 220 irradiator to be carried out at selected temperatures between 100 and 300 K. The principle of operation and the performance of this cryostat are described and results are given of a study into the behaviour of alanine dosimeters at cryogenic temperatures. This work extends previously published data to the region between solid CO{sub 2} and liquid N{sub 2} temperatures and has demonstrated complex dose-dependent behaviour. A sharp discontinuity in the effect of temperature on alanine dosimeter response has been found in the region between 150 and 180 K, with no further influence of irradiation temperature on response observed below this point.

  16. The behaviour of alanine dosimeters at temperatures between 100 and 300 K

    Science.gov (United States)

    Sharpe, P. H. G.; Sephton, J. P.; Gouldstone, C. A.

    2009-07-01

    A cryostat has been constructed to enable irradiations in a MDS Nordion Gammacell 220 irradiator to be carried out at selected temperatures between 100 and 300 K. The principle of operation and the performance of this cryostat are described and results are given of a study into the behaviour of alanine dosimeters at cryogenic temperatures. This work extends previously published data to the region between solid CO 2 and liquid N 2 temperatures and has demonstrated complex dose-dependent behaviour. A sharp discontinuity in the effect of temperature on alanine dosimeter response has been found in the region between 150 and 180 K, with no further influence of irradiation temperature on response observed below this point.

  17. Luminescent metal-organic framework films as highly sensitive and fast-response oxygen sensors.

    Science.gov (United States)

    Dou, Zhongshang; Yu, Jiancan; Cui, Yuanjing; Yang, Yu; Wang, Zhiyu; Yang, Deren; Qian, Guodong

    2014-04-16

    Luminescent metal-organic framework films, CPM-5⊃Tb(3+) and MIL-100(In)⊃Tb(3+), have been constructed by postfunctionalization of two porous indium-organic frameworks with different structures, respectively. The MIL-100(In)⊃Tb(3+) film shows high oxygen sensitivity (KSV = 7.59) and short response/recovery time (6 s/53 s).

  18. Combining the Converse Humidity/Resistance Response Behaviors of RGO Films for Flexible Logic Devices

    KAUST Repository

    Tai, Yanlong

    2017-03-23

    Carbon nanomaterials have excellent humidity sensing performance. Here, we demonstrate that reduced-graphene-oxide- (rGO) based conductive films with different thermal reduction times have gradient and invertible humidity/electrical resistance responses: rGO films (< 11 h, negative response, regarded as a signal of “0”), rGO films (around 11-13 h, balance point) and rGO films (> 13 h, negative response, regarded as a signal of “1”). We propose a new mechanism that describes a “scale”-like model for rGO films to explain these behaviors based on contributions from Ohm-contact resistance and capacitive reactance at interplate junctions, and intrinsic resistances of the nanoplates, respectively. This mechanism is accordingly validated via a series of experiments and electrical impedance spectroscopies, which complement more classical models based on proton conductivity. To explore the practical applications of the converse humidity/resistance responses, three simple flexible logic devices were developed, i) a rGO pattern for humidity-insensitive conductive film, which has the potential to greatly improve the stability of carbon-based electrical device to humidity; ii) a Janus pattern of rGO films for gesture recognition, which is very useful to human/machine interactions; iii) a sandwich pattern of rGO films for 3-dimensional (3D) noncontact sensing, which will be complementary to existing 3D touch technique.

  19. SINGLE ANODE TRIPLE GEM TISSUE EQUIVALENT PROPORTIONAL COUNTER AS THE BASIS FOR A PERSONAL NEUTRON DOSIMETER.

    Science.gov (United States)

    Seydaliev, M; Dubeau, J; Ali, F

    2017-04-28

    This paper reports on a tissue-equivalent proportional counter (TEPC) based on a triple gas electron multiplier structure, with a single pad readout, as a basis for a personal neutron dosimeter. Its dosimetric response was studied using the 252Cf neutron source at the Health Physics Generator Facility of the Canadian Nuclear Laboratories. Measured lineal energy spectra were found to be in agreement with numerical simulations performed with Monte Carlo N-Particle eXtended (MCNPX). Both simulations and measurements showed that the mean pathlength of secondary charged particles in the TEPC gas was best represented by the thickness of the drift region of the device. It was determined that the Cauchy Theorem, used to calculate the mean chord length in spherical and cylindrical TEPCs, overestimated the simulated mean chord length by nearly a factor of two. Important operational characteristics of the device were investigated, including gas gain, sensitivity and dosimetric response, as functions of tissue-equivalent gas pressure. This work demonstrates that the proposed design can serve as the basis for a personal neutron dosimeter device, which would satisfy the angular dosimetric response criteria of the personal dosimeter standard IEC61526. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. A study on the microwave responses of YBCO and TBCCO thin films by coplanar resonator technique

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    YBa2CuaO7(YBCO) thin films have been prepped by thermal coevaporation on LaAlO3 (LAO) substrates, and Tl2Ba2CaCu2O8(TBCCO) thin films are synthesized by magnetron sputtering method on LAO substrates. The transition temperature Tc is 90 K for YBCO/LAO and 104K for TBCCO/LAO. Microwave responses of the films are studied systematically by coplanar resonator technique. Energu gaps of the films obtained are △0 = 1.04kBTc for YBCO films and △0 = 0.84kBTc for TBCCO films by analysing the temperature dependence of resonant frequencies of coplanar resonator. Penetration depth at 0K λ0 = 198 nm for YBCO films and λ0 = 200 nm for TBCCO films could also be obtained by using the weak coupling theory and two fluid theory. Results of penetration depth and energy gap confirm the weak coupling properties of the films. In addition, microwave surface resistances Rs of YBCO/LAO and TBCCO/LAO are also investigated by analysing the quality factor and insert loss of the coplanar resonator. Surface resistance of TBCCO/LAO is less than that of YBCO/LAO, so that TBCCO/LAO films may have more potential applications.

  1. Light scattering in optical CT scanning of Presage dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Y; Adamovics, J; Cheeseborough, J C; Chao, K S; Wuu, C S, E-mail: yx2010@columbia.ed

    2010-11-01

    The intensity of the scattered light from the Presage dosimeters was measured using a Thorlabs PM100D optical power meter (Thorlabs Inc, Newton, NJ) with an optical sensor of 1 mm diameter sensitive area. Five Presage dosimeters were made as cylinders of 15.2 cm, 10 cm, 4 cm diameters and irradiated with 6 MV photons using a Varian Clinac 2100EX. Each dosimeter was put into the scanning tank of an OCTOPUS' optical CT scanner (MGS Research Inc, Madison, CT) filled with a refractive index matching liquid. A laser diode was positioned at one side of the water tank to generate a stationary laser beam of 0.8 mm width. On the other side of the tank, an in-house manufactured positioning system was used to move the optical sensor in the direction perpendicular to the outgoing laser beam from the dosimeters at an increment of 1 mm. The amount of scattered photons was found to be more than 1% of the primary light signal within 2 mm from the laser beam but decreases sharply with increasing off-axis distance. The intensity of the scattered light increases with increasing light attenuations and/or absorptions in the dosimeters. The scattered light at the same off-axis distance was weaker for dosimeters of larger diameters and for larger detector-to-dosimeter distances. Methods for minimizing the effect of the light scattering in different types of optical CT scanners are discussed.

  2. Terahertz response of GaN thin films.

    Science.gov (United States)

    Tsai, Tsong-Ru; Chen, Shi-Jie; Chang, Chih-Fu; Hsu, Sheng-Hsien; Lin, Tai-Yuan; Chi, Cheng-Chung

    2006-05-29

    The indices of refraction, extinction constants and complex conductivities of the GaN film for frequencies ranging from 0.2 to 2.5 THz are obtained using THz time-domain spectroscopy. The results correspond well with the Kohlrausch stretched exponential model. Using the Kohlrausch model fit not only provides the mobility of the free carriers in the GaN film, but also estimates the relaxation time distribution function and average relaxation time.

  3. Predicting Emotional Responses to Horror Films from Cue-Specific Affect.

    Science.gov (United States)

    Neuendorf, Kimberly A.; Sparks, Glenn G.

    1988-01-01

    Assesses individuals' fear and enjoyment reactions to horror films, applying theories of cognition and affect that predict emotional responses to a stimulus on the basis of prior affect toward specific cues included in that stimulus. (MM)

  4. Dosimetric characterization of the PTW Seven29 dosimeter and Octavius Phantom for IMRT quality control; Caracterizacao dosimetrica do dosimetro PTW Seven29 e Octavius Phantom para controle de qualidade em IMRT

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Leandro R.; Habitzreuter, Angela B.; Santos, Gabriela R.; Watanabe, Erica Y.; Silva, Marco A.; Menegussi, Gisela; Rodrigues, Laura N.; Furnari, Laura, E-mail: leandrorg11@hotmail.com [Instituto do Cacer do Estado de Sao Paulo (ICESP), SP (Brazil). Servico de Radioterapia

    2012-12-15

    Techniques like IMRT, VMAT and tomotherapy has been used to improve dose conformity in the target, while sparing adjacent normal tissues. The complexity of this techniques challenge to correctly verify the dose delivery, in an independent way. Matrix detectors have been used for this purpose. Although, to exactly understand the dosimeter response and to identify his limitations, characterization measurements need to be performed. These dosimeters, for instance, can present angular dependence. Phantoms has been designed to, when used together the detector, eliminate this angular dependence. The aim of this work was to characterize PTW Seven 29 dosimeter and also his use with Octavius Phantom (PTW). The dosimeter showed reproducible with 0.25% the biggest standard deviation, good dose linearity and dose rate independence. Differences for output factors were obtained (<6%), but a clinical case measurement showed that the set can be used for IMRT verification. When used with Octavius Phantom the dosimeter showed low angular dependence. (author)

  5. Personal noise dosimeters: accuracy and reliability in varied settings.

    Science.gov (United States)

    Cook-Cunningham, Sheri Lynn

    2014-01-01

    This study investigated the accuracy, reliability, and characteristics of three brands of personal noise dosimeters (N = 7 units) in both pink noise (PN) environments and natural environments (NEs) through the acquisition of decibel readings, Leq readings and noise doses. Acquisition periods included repeated PN conditions, choir room rehearsals and participant (N = 3) Leq and noise dosages procured during a day in the life of a music student. Among primary results: (a) All dosimeters exhibited very strong positive correlations for PN measurements across all instruments; (b) all dosimeters were within the recommended American National Standard Institute (ANSI) SI.25-1991 standard of ±2 dB (A) of a reference measurement; and (c) all dosimeters were within the recommended ANSI SI.25-1991 standard of ±2 dB (A) when compared with each other. Results were discussed in terms of using personal noise dosimeters within hearing conservation and research contexts and recommendations for future research. Personal noise dosimeters were studied within the contexts of PN environments and NEs (choral classroom and the day in the life of collegiate music students). This quantitative study was a non-experimental correlation design. Three brands of personal noise dosimeters (Cirrus doseBadge, Quest Edge Eg5 and Etymotic ER200D) were tested in two environments, a PN setting and a natural setting. There were two conditions within each environment. In the PN environment condition one, each dosimeter was tested individually in comparison with two reference measuring devices (Ivie and Easera) while PN was generated by a Whites Instrument PN Tube. In condition two, the PN procedures were replicated for longer periods while all dosimeters measured the sound levels simultaneously. In the NE condition one, all dosimeters were placed side by side on a music stand and recorded sound levels of choir rehearsals over a 7-h rehearsal period. In NE, condition two noise levels were measured during

  6. Cyanocobalamin solutions as potential dosimeters in low-dose food irradiations.

    Science.gov (United States)

    Prakasan, Velayudhan; Sanyal, Bhaskar; Pritamdas Chawla, Surinder; Chander, Ramesh; Sharma, Arun

    2014-04-01

    Potential of aqueous solutions of cyanocobalamin in gamma radiation dosimetry was investigated. The solutions are inexpensive, nontoxic and easy-to-prepare dosimeters, which could be useful for measuring gamma radiation doses in various applications, such as quarantine treatment of fruit or insect disinfestation of grains and pulses. The optical absorbance of cyanocobalamin solutions of the optimal concentration 0.08 mM decreases with increasing radiation dose. The reproducible dependence of the absorbance decrease on the dose can be described with a polynomial. Pre- and post-irradiation stability of the solution absorbance, as well as effects of the irradiation temperature and dose rate, were studied. The response is not significantly affected by storage of the irradiated dosimeters under ambient conditions for 20 days. The performance characteristics of this chemical dosimetry system suggest that it can be useful to measure doses in irradiations of food. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Radiation-sensitive indicator based on radiation-chemical formation of acids in polyvinyl butyral films containing chloral hydrate

    Science.gov (United States)

    Abdel-Fattah, Atef A.; El-Kelany, M.

    1998-03-01

    Radiation-sensitive indicators based on dyed polyvinyl butyral (PVB) containing acid-sensitive dye (bromophenol blue, BPB) and chloral hydrate (CCl 3CH(OH) 2, 2,2,2-trichloroethane-1, 1-diol) have been developed. These plastic film dosimeters undergo colour change from blue (the alkaline form of BPB) to yellow (the acidic form of BPB), indicating acid formation. The concentration of radiation-formed acids in the films containing different concentrations of chloral hydrate was calculated at different doses. The kinetics of the acid-formation reaction is discussed, indicating a half-order reaction with respect to chloral hydrate concentration. These films can be used as dosimeters for food irradiation applications where the maxima of the useful dose ranges are between 1 and 4 kGy depending on chloral hydrate concentration in the film. The response of these films depends on temperature during irradiation; therefore a correction should be applied. These films have the advantage of negligible humidity effects on response in the intermediate range of relative humidity from 10 to 70% as well as good post-irradiation stability when stored in the dark at room temperature.

  8. Multifactorial study and kinetics of signal development in ferrous-methylthymol blue-gelatin gel dosimeters.

    Science.gov (United States)

    Penev, Kalin I; Mequanint, Kibret

    2017-05-01

    To develop and characterize a ferrous-methylthymol blue-gelatin gel dosimeter with low optical background and appropriate additives for reduced rate of auto-oxidation and diffusion. A mixed-level multifactorial design of experiments was used to test the effects of the concentrations of sulfuric acid, 5-nitro-1,10-phenanthroline (Nn), and glyoxal (Gx) on the background absorbance, dose sensitivity, and auto-oxidation of the tested gel dosimeter. The dosimetric properties of the proposed ferrous-methylthymol blue-gelatin dosimeter, doped with Nn and Gx, were compared with the undoped formulation and with ferrous-xylenol orange-gelatin gel dosimeters. Irradiations were performed in both small-scale cuvette samples and large 400-mL bulk samples. In addition to that, a new kinetic model for the signal development postirradiation was derived based on chemical principles and used for comparison of the different formulations. The new formulation showed a reduced auto-oxidation rate, while maintaining low background absorbance relative to the common ferrous-xylenol orange-gelatin gel dosimeter. Compared with undoped ferrous-xylenol orange or ferrous-methylthymol blue gels, the dose sensitivity of the new formulation is approximately 2 to 3 times lower, but remains clinically adequate. A previously unreported dose rate dependence of the dose sensitivity was observed, and a new kinetic model for the signal development postirradiation was used to investigate this effect. Similar dose rate dependences in gels containing either methylthymol blue or xylenol orange, with or without doping with Nn and Gx, were observed, suggesting that the low ferrous ammonium sulfate concentrations used in studied formulations were responsible for this effect. A multifactorial design of experiments and a new kinetic model for the signal development postirradiation were successfully employed to optimize the composition and characterize the properties of a new ferrous-methylthymol blue-gelatin gel

  9. Evaluation of a multi-guard ring (MGR) structure diode as diagnostic X-ray dosimeter

    Science.gov (United States)

    Camargo, F.; Khoury, H. J.; Nascimento, C. R.; Asfora, V. K.; Bueno, C. C.

    2007-09-01

    In this paper, we describe the results obtained for the evaluation of a multi-guard ring (MGR) structure diode as diagnostic X-ray dosimeter. This device was developed in the framework of R&D programs for the future CMS experiment at the Large Hadron Collider (LHC) with high radiation hardness to fulfill the requirements from this accelerator environment. In order to use the MGR diode as a dosimeter, it was connected in the photovoltaic mode to the input of an integrating electrometer and positioned at the center of an X-ray beam, beside a previously calibrated ionization chamber. The dependence of the diode response on the X-ray beam doses was evaluated for 35-90 kV X-ray generator bias supply, with doses in the range of 50 μGy-5 mGy. The good linearity of the dose-response curve obtained showed the MGR diode dosimeter to be a reliable alternative method for diagnostic X-ray dosimetry.

  10. SU-E-T-353: Effects of Time and Temperature On a Potential Reusable 3D Dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Juang, T; Miles, D; Crockett, E [Medical Physics Graduate Program, Duke University Medical Center, Durham, NC (United States); Adamovics, J [Rider University, Skillman, NJ (United States); Oldham, M [Duke University Medical Center, Durham, NC (United States)

    2015-06-15

    Purpose: Preliminary studies of a novel, optically-clearing PRESAGE 3D dosimeter formulation (Presage-RU) demonstrated potential reusability. This study investigates the effects of time and temperature on the accuracy and reusability of Presage-RU, and reports on progress toward developing a reusable 3D dosimeter. Methods: Presage-RU was cast as small volume samples (1×1×4.5cm). The effect of dose response sensitivity with reirradiation and time was evaluated by irradiating samples from 0–10Gy, measuring change in optical density (ΔOD), clearing at room temperature (RT) (5–7 days to fully clear), and then repeating for a total of 5 irradiations. Effects of heating on clearing rate were investigated by irradiating samples to 8Gy, then tracking measurements with samples held at RT, 35°C, and 45°C. Two cylindrical dosimeters (11cm diameter, 9.5cm length) were evaluated for dosimetric accuracy when stored at RT and −3°C prior to irradiation. Plans delivered were 2 overlapping AP fields (RT) and VMAT (-3°C). Results: Heating the dosimeters reduced the clearing half-life from 16.3h at RT to 5.8h (35°C) and 5.1h (45°C), but also increased background ΔOD by 1.7x (35°C) and 2.3x (45°C). Reductions in dose response were more closely linked to age than reirradiation, and storage at RT showed pronounced desensitization from dosimeter edges. These results suggest desensitization from oxygen diffusion. It should be noted that atmospheric diffusion into the dosimeter is not seen in standard, single-use PRESAGE, and is likely caused by differences in the Presage-RU polyurethane matrix. The dosimeter kept in cold storage, however, showed no evidence of desensitization and exhibited accuracy on par with standard PRESAGE with a 3%/3mm 3D gamma passing rate of 98.1%. Conclusions: Presage-RU is sensitive to storage temperatures and time, both of which affect oxygen diffusion and subsequent desensitization. Development shows promising progress with further formulation

  11. Optical response and activity of ultrathin films of topological insulators

    Science.gov (United States)

    Parhizgar, Fariborz; Moghaddam, Ali G.; Asgari, Reza

    2015-07-01

    We investigate the optical properties of ultrathin film of a topological insulator in the presence of an in-plane magnetic field. We show that due to the combination of the overlap between the surface states of the two layers and the magnetic field, the optical conductivity can show strong anisotropy. This leads to the effective optical activity of the ultrathin film by influencing the circularly polarized incident light. Intriguingly, for a range of magnetic fields, the reflected and transmitted lights exhibit elliptic character. Even for certain values almost linear polarizations are obtained, indicating that the thin film can act as a polaroid in reflection. All these features are discussed in the context of the time-reversal symmetry breaking as one of the key ingredients for the optical activity.

  12. Performance characteristics of mobile MOSFET dosimeter for kilovoltage X-rays used in image guided radiotherapy

    Directory of Open Access Journals (Sweden)

    A Sathish Kumar

    2015-01-01

    Full Text Available The main objective of this study was to investigate the characteristics of metal oxide semiconductor field effect transistor (MOSFET dosimeter for kilovoltage (kV X-ray beams in order to perform the in vivo dosimetry during image guidance in radiotherapy. The performance characteristics of high sensitivity MOSFET dosimeters were investigated for 80, 90, 100, 110, 120, and 125 kV X-ray beams used for imaging in radiotherapy. This study was performed using Clinac 2100 C/D medical electron linear accelerator with on-board imaging and kV cone beam computed tomography system. The characteristics studied in this work include energy dependence, angular dependence, and linearity. The X-ray beam outputs were measured as per American Association of Physicists in Medicine (AAPM TG 61 recommendations using PTW parallel plate (PP ionization chamber, which was calibrated in terms of air kerma (Nk by the National Standard Laboratory. The MOSFET dosimeters were calibrated against the PP ionization chamber for all the kV X-ray beams and the calibration coefficient was found to be 0.11 cGy/mV with a standard deviation of about ±1%. The response of MOSFET was found to be energy independent for the kV X-ray energies used in this study. The response of the MOSFET dosimeter was also found independent of angle of incidence for the gantry angles in the range of 0° to 360° in-air as well as at 3 cm depth in tissue equivalent phantom.

  13. Some spectral response characteristics of ZnTe thin films

    Indian Academy of Sciences (India)

    R Sarma; N Mazumdar; H L Das

    2006-02-01

    Zinc telluride thin films have been grown at room temperature and higher temperature substrates by thermal evaporation technique in a vacuum of 10-6 torr. A main peak in the photocurrent is observed at 781 nm (1.58 eV) with two lower amplitude peaks on the lower wavelength side and one on higher wavelength side. The evaluated thermal activation energy is found to correspond well with the main spectral peak. From these studies it can be inferred that temperatures up to 453 K is still in the extrinsic conductivity region of the studied ZnTe thin films.

  14. Miniature Space Dosimeter Based on Semiconductor Oxides Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Space Micro and Clemson University have teamed for a miniature, ultra low power, space radiation dosimeter. We project this unit, "MicroRad", to be 50X...

  15. Tissue-Equivalent Radiation Dosimeter-On-A-Chip Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Many commercially available digital dosimeters are bulky and are unable to properly measure dose for space radiation. The complexity of space flight design requires...

  16. Tissue-Equivalent Radiation Dosimeter-On-A-Chip Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Available digital dosimeters are bulky and unable to provide real-time monitoring of dose for space radiation. The complexity of space-flight design requires...

  17. A Medipix-Based Small Personal Space Radiation Dosimeter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR effort will take the first step in improving the existing Medipix dosimeter technology in terms of advancing the technique now used to couple the actual...

  18. Surface-enhanced Raman scattering (SERS) dosimeter and probe

    Science.gov (United States)

    Vo-Dinh, Tuan

    1995-01-01

    A dosimeter and probe for measuring exposure to chemical and biological compounds is disclosed. The dosimeter or probe includes a collector which may be analyzed by surface-enhanced Raman spectroscopy. The collector comprises a surface-enhanced Raman scattering-active material having a coating applied thereto to improve the adsorption properties of the collector. The collector may also be used in automated sequential devises, in probe array devices.

  19. Overview on conductometric solid-state gas dosimeters

    OpenAIRE

    I. Marr; Groß, A.; Moos, R.

    2014-01-01

    The aim of this article is to introduce the operation principles of conductometric solid-state dosimeter-type gas sensors, which have found increased attention in the past few years, and to give a literature overview on promising materials for this purpose. Contrary to common gas sensors, gas dosimeters are suitable for directly detecting the dose (also called amount or cumulated or integrated exposure of analyte gases) rather than the actual analyte concentration. Therefore...

  20. Fricke gel dosimeter with improved sensitivity for low-dose-level measurements.

    Science.gov (United States)

    Vaiente, Mauro; Molina, Wladimir; Silva, Lila Carrizales; Figueroa, Rodolfo; Malano, Francisco; Pérez, Pedro; Santibañez, Mauricio; Vedelago, José

    2016-07-01

    Fricke solution has a wide range of applications as radiation detector and dosimetry. It is particularly appreciated in terms of relevant comparative advantages, like tissue-equivalence when prepared in aqueous media like gel matrix, continuous mapping capability, independence of dose rate and incident direction, as well as linear dose response. This work presents the development and characterization of an improved Fricke gel system, based on modified chemical compositions, making possible its application in clinical radiology due to its improved sensitivity. Properties of standard Fricke gel dosimeter for high-dose levels are used as a starting point, and suitable chemical modifications are introduced and carefully investigated in order to attain high resolution for low-dose ranges, like those corresponding to radiology interventions. The developed Fricke gel radiation dosimeter system achieves the expected typical dose-dependency, showing linear response in the dose range from 20 up to 4000 mGy. Systematic investigations including several chemical compositions are carried out in order to obtain an adequate dosimeter response for low-dose levels. A suitable composition from among those studied is selected as a good candidate for low-dose-level radiation dosimetry consisting of a modified Fricke solution fixed to a gel matrix containing benzoic acid along with sulfuric acid, ferrous sulfate, Xylenol orange, and tridistilled water. Dosimeter samples are prepared in standard vials for in-phantom irradiation and further characterization by spectrophotometry measuring visible light transmission and absorbance before and after irradiation. Samples are irradiated using typical X-ray tubes for radiology and calibrated Farmer-type ionization chamber is used as reference to measure dose rates inside phantoms at vial locations. Once sensitive material composition is optimized, dose-response curves show significant improvement regarding overall sensitivity for low dose levels

  1. Poly(acrylic acid surface grafted polypropylene films: Near surface and bulk mechanical response

    Directory of Open Access Journals (Sweden)

    2008-11-01

    Full Text Available Radical photo-grafting polymerization constitutes a promising technique for introducing functional groups onto surfaces of polypropylene films. According to their final use, surface grafting should be done without affecting overall mechanical properties. In this work the tensile drawing, fracture and biaxial impact response of biaxially oriented polypropylene commercial films grafted with poly(acrylic acid (PAA were investigated in terms of film orientation and surface modification. The variations of surface roughness, elastic modulus, hardness and resistance to permanent deformation induced by the chemical treatment were assessed by depth sensing indentation. As a consequence of chemical modification the optical, transport and wettability properties of the films were successfully varied. The introduced chains generated a PAA-grafted layer, which is stiffer and harder than the neat polypropylene surface. Regardless of the surface changes, it was proven that this kind of grafting procedure does not detriment bulk mechanical properties of the PP film.

  2. Irreversible thermochromic response of RF sputtered nanocrystalline BaWO4 films for smart window applications

    Directory of Open Access Journals (Sweden)

    C. Anil Kumar

    2015-10-01

    of oxygen vacancies and the formation of pure BWO phase. The obtained optical responses of BWO films are promising for solar cell and smart window applications.

  3. Irreversible thermochromic response of RF sputtered nanocrystalline BaWO4 films for smart window applications

    Science.gov (United States)

    Anil Kumar, C.; Santhosh Kumar, T.; Pamu, D.

    2015-10-01

    formation of pure BWO phase. The obtained optical responses of BWO films are promising for solar cell and smart window applications.

  4. Some Limitations in the Use of Plastic and Dyed Plastic Dosimeters

    DEFF Research Database (Denmark)

    Miller, Arne; Bjergbakke, Erling; McLaughlin, W. L.

    1975-01-01

    fractionated and uninterrupted absorbed doses in the megarad range with 60Co γ-rays and 10 MeV electron beams. It was found that with some systems, differences in radiation response due to dose-rate and temperature dependence can cause large systematic errors in dose interpretation. Poor reproducibility...... of response may result from batch-to-batch differences or intra-batch variations in thickness, distribution of sensitizers and background optical density. When using these routine dosimeters, careful calibration of the response and monitoring of factors contributing to poor reproducibility are essential....

  5. In vivo clinical dosimetry with LiF: PTFE dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, A. (Junta de Energia Nuclear, Madrid (Spain)); Manzanas, M.J.; Fernandez Leton, P. (Clinica Seg. Soc. 1. Octubre, Madrid (Spain))

    1984-01-01

    The purpose of this report is to describe the implementation of a dosimetric system suitable for ''in vivo'' measurements in some clinical applications. This system is based in re-usable thermoluminiscent dosimeters of Lithium fluoride embebded in teflon (PTFE). The results obtained in the utilization of these dosimeters for the determination of entrance absorbed doses on an antropomorphical phantom and patients are also presented. The irradiations have been made in several anatomical localizations with /sup 60/Co gamma rays. A great number of measurements has been made to determine properly the precision that can be reached with LiF: PTFE dosimeters. A considerable improvement of this precission has been obtained calibrating individually each dosimeter. The effects of the remanent sensibilization of the dosimeters that have received relatively high doses (approx. 1 Gy) are also reported. In order to take into account this unwanted effect it is necessary to calibrate frequently the dosimeters during their useful life, lowering, in this way, the risk of making wrong assignation of absorbed doses. From the results obtained in the measurements of absorbed doses in patients, it is clearly deduced that, even in anatomical localizations without special difficulties, such as the abdominal: flat and without problems to maintain the treatment position, rather high discrepancies can be found between the planned doses and those really imparted in practice. These results confirms the usefulness of making patient dose measurements in order to have effective control of the necessary quality of the therapeutical treatments.

  6. Dose-response of EBT3 radiochromic films to proton and carbon ion clinical beams

    Science.gov (United States)

    Castriconi, Roberta; Ciocca, Mario; Mirandola, Alfredo; Sini, Carla; Broggi, Sara; Schwarz, Marco; Fracchiolla, Francesco; Martišíková, Mária; Aricò, Giulia; Mettivier, Giovanni; Russo, Paolo

    2017-01-01

    We investigated the dose-response of the external beam therapy 3 (EBT3) films for proton and carbon ion clinical beams, in comparison with conventional radiotherapy beams; we also measured the film response along the energy deposition-curve in water. We performed measurements at three hadrontherapy centres by delivering monoenergetic pencil beams (protons: 63-230 MeV; carbon ions: 115-400 MeV/u), at 0.4-20 Gy dose to water, in the plateau of the depth-dose curve. We also irradiated the films to clinical MV-photon and electron beams. We placed the EBT3 films in water along the whole depth-dose curve for 148.8 MeV protons and 398.9 MeV/u carbon ions, in comparison with measurements provided by a plane-parallel ionization chamber. For protons, the response of EBT3 in the plateau of the depth-dose curve is not different from that of photons, within experimental uncertainties. For carbon ions, we observed an energy dependent under-response of EBT3 film, from 16% to 29% with respect to photon beams. Moreover, we observed an under-response in the Bragg peak region of about 10% for 148.8 MeV protons and of about 42% for 398.9 MeV/u carbon ions. For proton and carbon ion clinical beams, an under-response occurs at the Bragg peak. For carbon ions, we also observed an under-response of the EBT3 in the plateau of the depth-dose curve. This effect is the highest at the lowest initial energy of the clinical beams, a phenomenon related to the corresponding higher LET in the film sensitive layer. This behavior should be properly modeled when using EBT3 films for accurate 3D dosimetry.

  7. An ESR study on biological dosimeters: Human hair

    Energy Technology Data Exchange (ETDEWEB)

    Colak, Seyda, E-mail: seyda@hacettepe.edu.t [Hacettepe University, Physics Engineering Department, 06800 Ankara (Turkey); Ozbey, Turan [Hacettepe University, Physics Engineering Department, 06800 Ankara (Turkey)

    2011-05-15

    In the present work, characteristic features of the radicals found in untreated, gamma and UV-irradiated and mechanical damaged human hair samples were investigated by ESR spectroscopy. Heights of the resonance peaks measured with respect to the spectrum base line were used to monitor microwave power, dose-response, storage time and temperature dependent kinetic features of the radical species contributing to the formation of recorded experimental ESR spectra. Peak heights and g-values (2.0037-2.0052) determined from recorded spectra of hair were color dependent with {Delta}Hpp-0.47 mT. The act of cutting hair samples gene rates sulfur centered radicals which are found in the a-keratin structure of hair. The variations of the peak heights with temperature were related with the water content found in the hair samples. In the 6-1100 Gy dose range, a linear + quadratic dose-response curve was recorded for hair and the mean radiation yield (G{sub mean}) was calculated to be 0.4. The gamma radiation induced radicals were stable for a several hours at room temperature storage conditions. Based on these findings it was concluded that human hair samples could be used as biological/personnel dosimeters and that ESR spectroscopy could be successfully used as a potential technique for monitoring its dosimetric behaviours.

  8. Aqueous solution of basic fuchsin as food irradiation dosimeter

    Institute of Scientific and Technical Information of China (English)

    Hasan M. KHAN; Shagufta NAZ

    2007-01-01

    Dosimetric characterization of aqueous solution of basic fuchsin was studied spectrophotometrically for possible application in the low-dose food irradiation dosimetry. Absorption spectra of unirradiated and irradiated solutions were determined and the decrease in absorbance with the dose was noted down. Radiation-induced bleaching of the dye was measured at wavelengths of maximum absorption λmax (540nm) as well as 510nm and 460 nm. At all these wavelengths, the decrease in absorbance of the dosimeter was linear with respect to the absorbed dose from 50 Gy to 600 Gy. The stability of dosimetric solution during post-irradiation storage in the dark at room temperature showed that after initial bleaching during first ten to twenty days, the response was almost stable for about 34 days. The study on the effect of different light and temperature conditions also showed that the response gradually decreased during the storage period of 34 days, which shows that basic fuchsin dye is photosensitive as well as thermally sensitive.

  9. Real time radiation dosimeters based on vertically aligned multiwall carbon nanotubes and graphene

    Science.gov (United States)

    Funaro, Maria; Sarno, Maria; Ciambelli, Paolo; Altavilla, Claudia; Proto, Antonio

    2013-02-01

    Measurements of the absorbed dose and quality assurance programs play an important role in radiotherapy. Ionization chambers (CIs) are considered the most important dosimeters for their high accuracy, practicality and reliability, allowing absolute dose measurements. However, they have a relative large physical size, which limits their spatial resolution, and require a high bias voltage to achieve an acceptable collection of charges, excluding their use for in vivo dosimetry. In this paper, we propose new real time radiation detectors with electrodes based on graphene or vertically aligned multiwall carbon nanotubes (MWCNTs). We have investigated their charge collection efficiency and compared their performance with electrodes made of a conventional material. Moreover, in order to highlight the effect of nanocarbons, reference radiation detectors were also tested. The proposed dosimeters display an excellent linear response to dose and collect more charge than reference ones at a standard bias voltage, permitting the construction of miniaturized CIs. Moreover, an MWCNT based CI gives the best charge collection efficiency and it enables working also to lower bias voltages and zero volts, allowing in vivo applications. Graphene based CIs show better performance with respect to reference dosimeters at a standard bias voltage. However, at decreasing bias voltage the charge collection efficiency becomes worse if compared to a reference detector, likely due to graphene’s semiconducting behavior.

  10. Improving the Success Rate of Delivering Annual Occupational Dosimetry Reports to Persons Issued Temporary External Dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Mallett, Michael Wesley [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-09-09

    Workers who are not routinely monitored for occupational radiation exposure at LANL may be issued temporary dosimeters in the field. Per 10CFR835 and DOE O 231.1A, the Laboratory's radiation protection program is responsible for reporting these results to the worker at the end of the year. To do so, the identity of the worker and their mailing address must be recorded by the delegated person at the time the dosimeter is issued. Historically, this data has not been consistently captured. A new online application was developed to record the issue of temporary dosimeters. The process flow of the application was structured such that: 1) the worker must be uniquely identified in the Lab's HR database, and 2) the mailing address of record is verified live time via a commercial web service, for the transaction to be completed. A COPQ savings (Type B1) of $96K/year is demonstrated for the new application.

  11. Skin autofluorescence as a biological UVR dosimeter.

    Science.gov (United States)

    Sandby-Møller, J; Thieden, E; Philipsen, P A; Heydenreich, J; Wulf, H C

    2004-02-01

    Collagen is one of the major endogenous skin fluorophores. Alteration in the structure of collagen due to chronic ultraviolet radiation (UVR) exposure may influence the intensity of the autofluorescence. The aim of this study was to investigate the relation between collagen-linked autofluorescence and sun exposure to clarify whether the skin can be used as a biological UVR dosimeter. We conducted an in vivo study with 131 healthy volunteers. Fluorescence was measured from sun-exposed (dorsal forearm, forehead and shoulder) and sun-protected (buttock) skin and corrected for the impact of pigmentation and redness. The excitation wavelengths (Ex) and emission wavelengths (Em) were: Ex330:Em370, Ex330:Em455 and Ex370:Em455 nm. Individual UVR exposure data were collected both retrospectively and prospectively using questionnaires and electronic personal UVR dosimeters for a summer period. Age, but not sex, skin type or smoking habits correlated significantly positively with skin autofluorescence at Ex370:Em455 at all body sites (P<0.001, r(2)=0.08-0.26), and at Ex330:Em455 only at the buttock (P=0.001, r(2)=0.08), whereas age was not correlated with Ex330:Em370. Sun-protected buttock skin had significantly higher autofluorescence than sun-exposed skin (P-values<0.0001). Because of great between-subject differences in autofluorescence at different body sites, and because the autofluorescence at the unexposed buttock represents the baseline value, individual correction of skin autofluorescence measurement with that of the buttock was performed. Different measures of individual chronic cumulative UVR doses correlated significantly negatively with the skin autofluorescence ratio (F(ratio)), but the correlations were poor (r(2)=0.03-0.10). The results indicate that the collagen-linked skin F(ratio) might be best to use as a measure of individual photodamage, a UVR dose effect, and that it is also a better marker of individual cumulative UVR dose than the used UVR exposure

  12. Thermoluminescent response of aluminium oxide thin films subject to gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Arrieta, A.; Escobar A, L.; Camps, E.; Villagran, E.; Gonzalez, P.R

    2006-07-01

    The thermoluminescent (TL) properties of amorphous aluminium oxide thin films (thicknesses as low as 0.3 {mu}m) subjected to gamma (Co-60) irradiation are reported. Aluminium oxide thin films were prepared by laser ablation from an Al{sub 2}O{sub 3} target using a Nd: YAG laser with emission at the fundamental line. The films were exposed to gamma radiation (Co-60) in order to study their TL response. Thermoluminescence glow curves exhibited two peaks at 110 and 176 C. The high temperature peak shows good stability and 30% fading in the first 5 days after irradiation. A linear relationship between absorbed dose and the thermoluminescent response for doses span from 150 mGy to 100 Gy was observed. These results suggest that aluminium oxide thin films are suitable for detection and monitoring of gamma radiation. (Author)

  13. Frictional Response of Molecularly Thin Liquid Polymer Films Subject to Constant Shear Stress

    Science.gov (United States)

    Tschirhart, Charles; Troian, Sandra

    2014-03-01

    Measurements of the frictional response of nanoscale viscous films are typically obtained using the surface force apparatus in which a fluid layer is confined between smooth solid substrates approaching at constant speed or force. The squeezing pressure causes lateral flow from which the shear viscosity can be deduced. Under these conditions however, molecularly thin films tend to solidify wholly or partially and estimates of the shear viscosity can exceed those in macroscale films by many orders of magnitude. This problem can be avoided altogether by examining the response of an initially flat, supported, free surface film subject to comparable values of surface shear stress by application of an external inert gas stream. This method was first conceived by Derjaguin in 1944; more recent studies by Mate et al. at IBM Almaden on complex polymeric systems have uncovered fluid layering and other interesting behaviors. The only drawback is that this alternative technique requires an accurate model for interface distortion. We report on ellipsometric measurements of ultrathin polymeric films in efforts to determine whether the usual interface equations for free surface films based purely on continuum models can be properly extended to nanoscale films. Supported by a Fred and Jean Felberg Fellowship and G. W. Housner Student Discovery Fund.

  14. Cylindrical PVF2 film based fiber optic phase modulator - Phase shift nonlinearity and frequency response

    Science.gov (United States)

    Sudarshanam, V. S.; Claus, Richard O.

    1993-03-01

    A new cylindrical coil configuration for polyvinylidene flouride (PVF2) film based fiber optic phase modulator is studied for the frequency response and nonlinearity of phase shift at the resonance frequency. This configuration, hitherto unapproached for PVF2 film modulators, offers resonance at well defined, controllable and higher frequencies than possible for the flat-strip configuration. Two versions of this configuration are presented that differ strongly in both the resonance frequency and the phase shift nonlinearity coefficient.

  15. PDT dose dosimeter for pleural photodynamic therapy

    Science.gov (United States)

    Kim, Michele M.; Darafsheh, Arash; Ahmad, Mahmoud; Finlay, Jarod C.; Zhu, Timothy C.

    2016-03-01

    PDT dose is the product of the photosensitizer concentration and the light fluence in the target tissue. For improved dosimetry during plural photodynamic therapy (PDT), a PDT dose dosimeter was developed to measure both the light fluence and the photosensitizer concentration simultaneously in the same treatment location. Light fluence and spectral data were rigorously compared to other methods of measurement (e.g. photodiode, multi-fiber spectroscopy contact probe) to assess the accuracy of the measurements as well as their uncertainty. Photosensitizer concentration was obtained by measuring the fluorescence of the sensitizer excited by the treatment light. Fluence rate based on the intensity of the laser spectrum was compared to the data obtained by direct measurement of fluence rate by a fiber-coupled photodiode. Phantom studies were done to obtain an optical property correction for the fluorescence signal. Measurements were performed in patients treated Photofrin for different locations in the pleural cavity. Multiple sites were measured to investigate the heterogeneity of the cavity and to provide cross-validation via relative dosimetry. This novel method will allow for accurate real-time determination of delivered PDT dose and improved PDT dosimetry.

  16. Radiochromic film dosimetry. Considerations on precision and accuracy for EBT2 and EBT3 type films

    Energy Technology Data Exchange (ETDEWEB)

    Dreindl, Ralf [Medical Univ. of Vienna/Vienna General Hospital (Austria). Dept. of Radiooncology; EBG MedAustron GmbH, Wiener Neustadt (Austria); Georg, Dietmar; Stock, Markus [Medical Univ. of Vienna/Vienna General Hospital (Austria). Dept. of Radiooncology; Medical Univ. of Vienna (Austria). Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology

    2014-09-01

    Gafchromic {sup registered} EBT2 film is a widely used dosimetric tool for quality assurance in radiation therapy. In 2012 EBT3 was presented as a replacement for EBT2 films. The symmetric structure of EBT3 films to reduce face-up/down dependency as well as the inclusion of a matte film surface to frustrate Newton Ring artifacts present the most prominent improvements of EBT3 films. The aim of this study was to investigate the characteristics of EBT3 films, to benchmark the films against the known EBT2-features and to evaluate the dosimetric behavior over a time period greater than 6 months. All films were irradiated to clinical photon beams (6MV, 10MV and 18MV) on an Elekta Synergy Linac equipped with a Beam Modulator MLC in solid water phantom slabs. Film digitalization was done with a flatbed transparency scanner (Type Epson Expression 1680 Pro). MATLAB {sup registered} was used for further statistical calculations and image processing. The investigations on post-irradiation darkening, film orientation, film uniformity and energy dependency resulted in negligible differences between EBT2 and EBT3 film. A minimal improvement in face-up/down dependence was found for EBT3. The matte film surface of EBT3 films turned out to be a practical feature as Newton rings could be eliminated completely. Considering long-term behavior (> 6 months) a shift of the calibration curve for EBT2 and EBT3 films due to changes in the dynamic response of the active component was observed. In conclusion, the new EBT3 film yields comparable results to its predecessor EBT2. The general advantages of radiochromic film dosimeters are completed by high film homogeneity, low energy dependence for the observed energy range and a minimized face-up/down dependence. EBT2 dosimetry-protocols can also be used for EBT3 films, but the inclusion of periodical recalibration-interval (e.g. once a quarter) is recommended for protocols of both film generations. (orig.)

  17. Few layer graphene to graphitic films: infrared photoconductive versus bolometric response

    Science.gov (United States)

    Kurra, Narendra; Bhadram, Venkata Srinu; Narayana, Chandrabhas; Kulkarni, Giridhar U.

    2012-12-01

    incandescent bulb is shown in Fig. S4. Fig. S5 shows the fall and rise of resistance of the FLG with respect to the IR beam turning on and off respectively. The temporal IR photoresponse of the FLG films on the quartz and sapphire substrates is shown in Fig. S6. Rise and fall curves for the resistance of the bulk graphitic samples are shown in Fig. S7. The band level diagram in Fig. S8 explains the photoconductive and bolometric responses of the graphitic samples. See DOI: 10.1039/c2nr32861e

  18. Preparation of CaF{sub 2}:Dy chips as thermoluminescent dosimeters for environmental measurements using a Harshaw 2080 TL picoprocessor

    Energy Technology Data Exchange (ETDEWEB)

    Matoso, Erika; Leite, Barbara Eliodora [Centro Tecnologico da Marinha em Sao Paulo (CTMSP/CEA), Ipero, SP (Brazil). Centro Experimental Aramar; Nunes, Maira Goes [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    This work presents the necessary steps to prepare the dosimeters for application in environmental measurements. The material used was calcium fluoride doped with dysprosium (CaF{sub 2}: Dy), commercially supplied by Harshaw as TLD-200. It were carried out four initial irradiations (Co-60 source gamma - 0.8 mGy from Dosimetric Material Laboratory LMD/GMP) in a new batch of TLD-200 dosimeters to achieve a stable response and four more irradiations to separate them, according to their response range. A batch of pre-selected 197 dosimeters from 263 was used to finally obtained two batches of 99 (9.2{+-}0.7nC) and 93 (10.5{+-}0.6nC) dosimeters. A calibration curve was prepared relating the thermoluminescent response of the phosphor and the radiation exposure (0 to 600{mu}Gy), obtained by irradiation with Co-60 source of 4P geometry and measurements using a Harshaw Picoprocessor 2080 TL equipment. Repeatability of the measurements was determined for 100{mu}Gy (CV= 5.09%) and 300{mu}Gy (CV=4.18%) and the minimum detectable dose was evaluated as 2{mu}Gy. The fading was determined by irradiating the dosimeters with 0.8 mGy and reading then after 1, 5, 7, 8, 15, 29, 50, 70 and 90 days. (author)

  19. Neutron Fading Characteristics of Copper Doped Lithium Fluoride (LiF: MCP) Thermoluminescent Dosimeters (TLDs)

    Science.gov (United States)

    2008-05-21

    particular type of radiation and has the SI units of Sieverts (Sv) or traditional units of Roentgen Equivalent Man ( rem ). It is calculated by multiplying...dosimeter was irradiated to 50 mSv (5 Rem ). The 10.31 pC 194.5 ROil 689.6 ROl2 8285. ROl3 1040. ROl4 ECC Ra= 1 pA 20 .. 43 44 .. 57 58- 75 76- 92...Methods Laboratory SDDML in Beijing, China shows a sub linear response at about 12 Gy.[73] Italian scientists have effectively measured the dose response

  20. Convective response of a wall-mounted hot-film sensor in a shock tube

    Science.gov (United States)

    Roberts, A. Sidney, Jr.; Ortgies, Kelly R.; Gartenberg, Ehud; Carraway, Debra L.

    1991-01-01

    Shock tube experiments were performed in order to determine the response of a single hot-film element of a sensor array to transiently induced flow behind weak normal shock waves. The experiments attempt to isolate the response due only to the change in convective heat transfer at the hot-film surface mounted on the wall of the shock tube. The experiments are described, the results being correlated with transient boundary layer theory and compared with an independent set of experimental results. One of the findings indicates that the change in the air properties (temperature and pressure) precedes the air mass transport, causing an ambiguity in the sensor response to the development of the velocity boundary layer. Also, a transient, local heat transfer coefficient is formulated to be used as a forcing function in an hot-film instrument model and simulation which remains under investigation.

  1. Research on the piezoelectric response of cubic and hexagonal boron nitride films

    Institute of Scientific and Technical Information of China (English)

    CHEN Xi-ming; SUN Lian-jie; YANG Bao-he; GUO Yan; WU Xiao-guo

    2012-01-01

    Boron nitride (BN) films for high-frequency surface acoustic wave (SAW) devices are deposited on Ti/A(l)/Si(111) wafers byradio frequency (RF) magnetron sputtering.The structure of BN films is investigated by Fourier transform infrared (FTIR)spectroscopy and X-ray diffraction (XRD) spectra,and the surface morphology and piezoelectric properties of BN films are characterized by atomic force microscopy (AFM).The results show that when the flow ratio of nitrogen and argon is 2∶18,the cubic BN (c-BN) film is deposited with high purity and c-axis orientation,and when the flow ratio of nitrogen and argon is 4∶20,the hexagonal BN (h-BN) film is deposited with high c-axis orientation.Both particles are uniform and compact,and the roughnesses are 1.5 nm and 2.29 nm,respectively.The h-BN films have better piezoelectric response and distribution than the c-BN films.

  2. Highly Magneto-Responsive Elastomeric Films Created by a Two-Step Fabrication Process

    KAUST Repository

    Marchi, Sophie

    2015-08-24

    An innovative method for the preparation of elastomeric magnetic films with increased magneto-responsivity is presented. Polymeric films containing aligned magnetic microchains throughout their thickness are formed upon the magnetophoretic transport and assembly of microparticles during polymer curing. The obtained films are subsequently magnetized at a high magnetic field of 3 T directed parallel to the orientation of the microchains. We prove that the combination of both alignment of the particles along a favorable direction during curing and the subsequent magnetization of the solid films induces an impressive increase of the films’ deflection. Specifically, the displacements reach few millimeters, up to 85 times higher than those of the nontreated films with the same particle concentration. Such a process can improve the performance of the magnetic films without increasing the amount of magnetic fillers and, thus, without compromising the mechanical properties of the resulting composites. The proposed method can be used for the fabrication of magnetic films suitable as components in systems in which large displacements at relatively low magnetic fields are required, such as sensors and drug delivery or microfluidic systems, especially where remote control of valves is requested to achieve appropriate flow and mixing of liquids.

  3. New Fast Response Thin Film-Based Superconducting Quench Detectors

    CERN Document Server

    Dudarev, A; van de Camp, W; Ravaioli, E; Teixeira, A; ten Kate, H H J

    2014-01-01

    Quench detection on superconducting bus bars and other devices with a low normal zone propagation velocity and low voltage build-up is quite difficult with conventional quench detection techniques. Currently, on ATLAS superconducting bus bar sections, superconducting quench detectors (SQD) are mounted to detect quench events. A first version of the SQD essentially consists of an insulated superconducting wire glued to a superconducting bus line or windings, which in the case of a quench rapidly builds up a relatively high resistance that can be easily and quietly detected. We now introduce a new generation of drastically improved SQDs. The new version makes the detection of quenches simpler, more reliable, and much faster. Instead of a superconducting wire, now a superconducting thin film is used. The layout of the sensor shows a meander like pattern that is etched out of a copper coated 25 mu m thick film of Nb-Ti glued in between layers of Kapton. Since the sensor is now much smaller and thinner, it is easi...

  4. Spin-Casting Polymer Brush Films for Stimuli-Responsive and Anti-Fouling Surfaces.

    Science.gov (United States)

    Xu, Binbin; Feng, Chun; Hu, Jianhua; Shi, Ping; Gu, Guangxin; Wang, Lei; Huang, Xiaoyu

    2016-03-01

    Surfaces modified with amphiphilic polymers can dynamically alter their physicochemical properties in response to changes of their environmental conditions; meanwhile, amphiphilic polymer coatings with molecular hydrophilic and hydrophobic patches, which can mitigate biofouling effectively, are being actively explored as advanced coatings for antifouling materials. Herein, a series of well-defined amphiphilic asymmetric polymer brushes containing hetero side chains, hydrophobic polystyrene (PS) and hydrophilic poly(ethylene glycol) (PEG), was employed to prepare uniform thin films by spin-casting. The properties of these films were investigated by water contact angle, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and quartz crystal microbalance (QCM). AFM showed smooth surfaces for all films with the roughness less than 2 nm. The changes in water contact angle and C/O ratio (XPS) evidenced the enrichment of PEG or PS chains at film surface after exposed to selective solvents, indicative of stimuli- responsiveness. The adsorption of proteins on PEG functionalized surface was quantified by QCM and the results verified that amphiphilic polymer brush films bearing PEG chains could lower or eliminate protein-material interactions and resist to protein adsorption. Cell adhesion experiments were performed by using HaCaT cells and it was found that polymer brush films possess good antifouling ability.

  5. CO Responses of Sensors Based on Cerium Oxide Thick Films Prepared from Clustered Spherical Nanoparticles

    OpenAIRE

    Woosuck Shin; Takafumi Akamatsu; Toshio Itoh; Ichiro Matsubara; Noriya Izu

    2013-01-01

    Various types of CO sensors based on cerium oxide (ceria) have been reported recently. It has also been reported that the response speed of CO sensors fabricated from porous ceria thick films comprising nanoparticles is extremely high. However, the response value of such sensors is not suitably high. In this study, we investigated methods of improving the response values of CO sensors based on ceria and prepared gas sensors from core-shell ceria polymer hybrid nanoparticles. These hybrid nano...

  6. Thin-film scintillators for extended ultraviolet /UV/ response silicon detectors

    Science.gov (United States)

    Viehmann, W.

    1979-01-01

    The preparation and radiometric properties of silicon detectors coated with fluorescent thin films are described. The films are deposited from solutions of clear plastics, such as acrylic resins, polyvinyl toluene or polystyrene, and of organic laser dyes in a common solvent. They are optically clear, mechanically and chemically stable, yet easily applied and removed. Multiple doped films of a few microns thickness exhibit broad-band absorption from less than 250 nm to about 450 nm and narrow band emissions with peaks ranging from 380 nm to 600 nm. Internal quantum efficiencies are close to 100 percent and fluorescence decay times are in the nanosecond range. When deposited on optically denser media, a large fraction of the fluorescent emission is trapped in the substrate. Silicon photodiodes coated with multiple doped films exhibit high external quantum efficiencies and virtually flat photon response in the near UV.

  7. Thin-film scintillators for extended ultraviolet /UV/ response silicon detectors

    Science.gov (United States)

    Viehmann, W.

    1979-01-01

    The preparation and radiometric properties of silicon detectors coated with fluorescent thin films are described. The films are deposited from solutions of clear plastics, such as acrylic resins, polyvinyl toluene or polystyrene, and of organic laser dyes in a common solvent. They are optically clear, mechanically and chemically stable, yet easily applied and removed. Multiple doped films of a few microns thickness exhibit broad-band absorption from less than 250 nm to about 450 nm and narrow band emissions with peaks ranging from 380 nm to 600 nm. Internal quantum efficiencies are close to 100 percent and fluorescence decay times are in the nanosecond range. When deposited on optically denser media, a large fraction of the fluorescent emission is trapped in the substrate. Silicon photodiodes coated with multiple doped films exhibit high external quantum efficiencies and virtually flat photon response in the near UV.

  8. Bioelectrochemical Response and Kinetics of Choline Oxidase Entrapped in Polyaniline-Polyacrylonitrile Composite Film

    Institute of Scientific and Technical Information of China (English)

    XUE,Huai-Guo(薛怀国); SHEN,Zhi-Quan(沈之荃)

    2002-01-01

    A novel choline oxidase electrode was constructed by entrapping choline oxidase into polyaniline-polyacrylonitrile composite film. The enzyme film was prepared by in situ electropolymerization of aniline into porous polyacrylonitrile-coated platinum electrode in the presence of choline oxidase. The enzyme electrode exhibited sensitive and stable electrochemical response to choline. The kinetics analysis showed that the mass transport is partially rate-limiting. The influences of pH, applied potential and temperature on the response of the enzyme electrode were also described.

  9. Achievement of controlled resistive response of nanogapped palladium film to hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, M. [Research Center for Solid State Physics and Materials, School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009 (China); Wong, M. H.; Ong, C. W., E-mail: c.w.ong@polyu.edu.hk [Department of Applied Physics and Materials Research Center, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

    2015-07-20

    Palladium (Pd) film containing nanogaps of well controlled dimension was fabricated on a Si wafer having a high-aspect-ratio micropillar. The Pd film was arranged to experience hydrogen (H{sub 2})-induced volume expansion. (i) If the nanogap is kept open, its width is narrowed down. A discharge current was generated to give a strong, fast, and repeatable on-off type resistive switching response. (ii) If the nanogap is closed, the cross section of the conduction path varies to give continuous H{sub 2}-concentration dependent resistive response. The influence of stresses and related physical mechanisms are discussed.

  10. PNNL Results from 2010 CALIBAN Criticality Accident Dosimeter Intercomparison Exercise

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Robin L.; Conrady, Matthew M.

    2011-10-28

    This document reports the results of the Hanford personnel nuclear accident dosimeter (PNAD) and fixed nuclear accident dosimeter (FNAD) during a criticality accident dosimeter intercomparison exercise at the CEA Valduc Center on September 20-23, 2010. Pacific Northwest National Laboratory (PNNL) participated in a criticality accident dosimeter intercomparison exercise at the Commissariat a Energie Atomique (CEA) Valduc Center near Dijon, France on September 20-23, 2010. The intercomparison exercise was funded by the U.S. Department of Energy, Nuclear Criticality Safety Program, with Lawrence Livermore National Laboratory as the lead Laboratory. PNNL was one of six invited DOE Laboratory participants. The other participating Laboratories were: Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Savannah River Site (SRS), the Y-12 National Security Complex at Oak Ridge, and Sandia National Laboratory (SNL). The goals of PNNL's participation in the intercomparison exercise were to test and validate the procedures and algorithm currently used for the Hanford personnel nuclear accident dosimeters (PNADs) on the metallic reactor, CALIBAN, to test exposures to PNADs from the side and from behind a phantom, and to test PNADs that were taken from a historical batch of Hanford PNADs that had varying degrees of degradation of the bare indium foil. Similar testing of the PNADs was done on the Valduc SILENE test reactor in 2009 (Hill and Conrady, 2010). The CALIBAN results are reported here.

  11. A critical assessment of two types of personal UV dosimeters.

    Science.gov (United States)

    Seckmeyer, Gunther; Klingebiel, Marcus; Riechelmann, Stefan; Lohse, Insa; McKenzie, Richard L; Liley, J Ben; Allen, Martin W; Siani, Anna-Maria; Casale, Giuseppe R

    2012-01-01

    Doses of erythemally weighted irradiances derived from polysulphone (PS) and electronic ultraviolet (EUV) dosimeters have been compared with measurements obtained using a reference spectroradiometer. PS dosimeters showed mean absolute deviations of 26% with a maximum deviation of 44%, the calibrated EUV dosimeters showed mean absolute deviations of 15% (maximum 33%) around noon during several test days in the northern hemisphere autumn. In the case of EUV dosimeters, measurements with various cut-off filters showed that part of the deviation from the CIE erythema action spectrum was due to a small, but significant sensitivity to visible radiation that varies between devices and which may be avoided by careful preselection. Usually the method of calibrating UV sensors by direct comparison to a reference instrument leads to reliable results. However, in some circumstances the quality of measurements made with simple sensors may be over-estimated. In the extreme case, a simple pyranometer can be used as a UV instrument, providing acceptable results for cloudless skies, but very poor results under cloudy conditions. It is concluded that while UV dosimeters are useful for their design purpose, namely to estimate personal UV exposures, they should not be regarded as an inexpensive replacement for meteorological grade instruments. © 2011 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2011 The American Society of Photobiology.

  12. Photon and neutron kerma coefficients for polymer gel dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    El-Khayatt, A.M., E-mail: Ahmed_el_khayatt@yahoo.com [Physics Department, College of Science, Al Imam Mohammad Ibn Saud Islamic University (IMSIU) (Saudi Arabia); Reactor Physics Department, Nuclear Research Centre, Atomic Energy Authority, 13759 Cairo (Egypt); Vega-Carrillo, Hector Rene [Unidad Academica de Estudios Nucleares, Universidad Autonoma de Zacatecas, C. Cipres 10, Fracc. La Peñuela, 98068 Zacatecas, Zac. (Mexico)

    2015-08-21

    Neutron and gamma ray kerma coefficients were calculated for 17 3D dosimeters, for the neutron and gamma ray energy ranges extend from 2.53×10{sup −8} to 29 MeV and from 1.0×10{sup −3} to 20 MeV, respectively. The calculated kermas given here for discrete energies and the kerma coefficients are referred to as “point-wise data”. Curves of gamma ray kermas showed slight dips at about 60 keV for most 3D dosimeters. Also, a noticeable departure between thermal and epithermal neutrons kerma sets for water and polymers has been observed. Finally, the obtained results could be useful for dose estimation in the studied 3D dosimeters. - Highlights: • Neutron and gamma ray kerma coefficients were calculated in 17 3D dosimeters. • Curves of gamma-ray kermas showed slight dips at about 60 keV. • Disagreement between neutron kermas for water and polymers has been observed. • The obtained results could be useful for dose estimation in the studied dosimeters.

  13. SU-E-T-511: Do Presage 3D Dosimeters Show Dose Fractionation Sensitivity?

    Energy Technology Data Exchange (ETDEWEB)

    Klawikowski, S; Alqathami, M; Ibbott, G [UT MD Anderson Cancer Center, Houston, TX (United States); Adamovics, J [John Adamovics, Skillman, NJ (United States); Benning, R [Rider University, Lawrenceville, NJ (United States)

    2014-06-01

    Purpose: To determine whether Presage 3D polymer dosimeter dose response is sensitive to dose delivery fractionation. Bang gels have demonstrated a dose fractionation related dependence in which a single 400 cGy irradiation would produce a different detector response than four 100 cGy irradiations even if delivered closely in time to one another. Such a fractional dependent response in Presage would be detrimental for measuring multi-beam irradiations. Methods: Two separate batches of Presage were poured into cuvettes, and a third batch was molded into cuvette shaped blocks. A total of 37 cuvettes/blocks were irradiated in a Cobalt-60 irradiator to 400 cGy within solid water phantoms in either one, eight, or sixteen fractions. Another group of 15 cuvettes were also kept unirradiated and used for background subtraction between the pre-scan and post-scan results. The times between fractional deliveries were held constant at 30 seconds and the Cobalt irradiator dose rate was 49 cGy/min. Each Presage batch has a separate dose sensitivity and therefore fractionation response comparisons were only performed within the same batch. The cuvettes were first pre-scanned the day prior to irradiation and post-scanned the day after irradiation. Other than approximately 3 hours warming time prior to each irradiation and optical density measurement the cuvettes were stored in a refrigerator. All cuvettes were stored in a lightless environment throughout manufacturing and testing. The cuvettes’ optical densities were optically measured at 632 nm with a spectrophotometer. Results: No noticeable dose fractionation dependence was detected for any of the three independent batches of Presage for either the eight or sixteen fraction irradiation schemes. Conclusion: These results indicate using Presage 3D dosimeters to measure multi-beam photon irradiations common in IMRT, Gamma Knife, and Cyberknife treatment delivery schemes. Presage dosimeters are made by and trademarked by Heuris

  14. Investigation of the energy response of EBT-2 GAFCHROMIC(TM) film model

    Science.gov (United States)

    Singh, Khushdeep

    The aim of this project is to quantify the energy response of the existing EBT-2 model GAFCHROMIC™ film and investigate for the eventual possible chemical compositions with improved energy response. In this work, the overall energy dependence of the EBT-2 model GAFCHROMIC™ film is quantized through intrinsic and absorbed dose energy response. Absorbed dose energy response is studied by calculating dose to film sensitive layer and dose to water using DOSRZnrc of EGSnrcMP Monte Carlo user-code. The film was simulated inside a large body of solid water for megavoltage beams, while at kilovoltage energies the film was modeled in air. The simulations were repeated to score the dose to water for megavoltage and air kerma for kilo-voltage beams, respectively. The intrinsic energy response is quantified through a measurement of total energy response divided by the Monte Carlo calculated absorbed dose energy response. The measurements consisted of delivering an exact dose of 2 Gy to the sensitive layer of the film at orthovoltage energies (50 kVp, 120 kVp, and 180 kVp), 192Ir and 60Co beam. AAPM TG-51 and TG-61 reports were used to determine the dose-to-water and air-kerma in air in megavoltage and orthovoltage beams, respectively, while Monte Carlo simulated corrections were used to convert these results to the desired dose to the sensitive layer of the film. For EBT-2 model GAFCHROMIC™ film, the overall energy dependence was found to vary by 39 % in the effective energy range from 24 keV to 1.25 MeV (for 60Co beam). It was determined that intrinsic (LET-dependent) energy dependence also plays an important role in the total energy dependence of EBT-2 model GAFCHROMIC™ film and cannot be ignored. The absorbed dose energy dependence was also studied for a wide variety of film active layer compositions in a 10 keV-100 keV energy range as well as at 60Co using Monte Carlo simulations. The composition of the film active layer was varied according to physical limits set

  15. Dynamic and temperature dependent response of physical vapor deposited Se in freely standing nanometric thin films

    Science.gov (United States)

    Yoon, Heedong; McKenna, Gregory B.

    2016-05-01

    Here, we report results from an investigation of nano-scale size or confinement effects on the glass transition and viscoelastic properties of physical vapor deposited selenium films. The viscoelastic response of freely standing Se films was determined using a biaxial membrane inflation or bubble inflation method [P. A. O'Connell and G. B. McKenna, Science 307, 1760-1763 (2005)] on films having thicknesses from 60 to 267 nm and over temperatures ranging from Tg, macroscopic - 15 °C to Tg, macroscopic + 21 °C. Time-temperature superposition and time-thickness superposition were found to hold for the films in the segmental dispersion. The responses are compared with macroscopic creep and recoverable creep compliance data for selenium [K. M. Bernatz et al., J. Non-Cryst. Solids 307, 790-801 (2002)]. The time-temperature shift factors for the thin films show weaker temperature dependence than seen in the macroscopic behavior, being near to Arrhenius-like in their temperature dependence. Furthermore, the Se films exhibit a "rubbery-like" stiffening that increases as film thickness decreases similar to prior observations [P. A. O'Connell et al., Macromolecules 45(5), 2453-2459 (2012)] for organic polymers. In spite of the differences from the macroscopic behavior in the temperature dependence of the viscoelastic response, virtually no change in Tg as determined from the thickness dependence of the retardation time defining Tg was observed in the bubble inflation creep experiments to thicknesses as small as 60 nm. We also find that the observed rubbery stiffening is consistent with the postulate of K. L. Ngai et al. [J. Polym. Sci., Part B: Polym. Phys. 51(3), 214-224 (2013)] that it should correlate with the change of the macroscopic segmental relaxation.

  16. CO responses of sensors based on cerium oxide thick films prepared from clustered spherical nanoparticles.

    Science.gov (United States)

    Izu, Noriya; Matsubara, Ichiro; Itoh, Toshio; Akamatsu, Takafumi; Shin, Woosuck

    2013-03-08

    Various types of CO sensors based on cerium oxide (ceria) have been reported recently. It has also been reported that the response speed of CO sensors fabricated from porous ceria thick films comprising nanoparticles is extremely high. However, the response value of such sensors is not suitably high. In this study, we investigated methods of improving the response values of CO sensors based on ceria and prepared gas sensors from core-shell ceria polymer hybrid nanoparticles. These hybrid nanoparticles have been reported to have a unique structure: The core consists of a cluster of ceria crystallites several nanometers in size. We compared the characteristics of the sensors based on thick films prepared from core-shell nanoparticles with those of sensors based on thick films prepared from conventionally used precipitated nanoparticles. The sensors prepared from the core-shell nanoparticles exhibited a resistance that was ten times greater than that of the sensors prepared from the precipitated nanoparticles. The response values of the gas sensors based on the core-shell nanoparticles also was higher than that of the sensors based on the precipitated nanoparticles. Finally, improvements in sensor response were also noticed after the addition of Au nanoparticles to the thick films used to fabricate the two types of sensors.

  17. LET dependence of the response of EBT2 films in proton dosimetry modeled as a bimolecular chemical reaction

    Science.gov (United States)

    Perles, L. A.; Mirkovic, D.; Anand, A.; Titt, U.; Mohan, R.

    2013-12-01

    The dose response for films exposed to clinical x-ray beams is not linear and a calibration curve based on absorbed dose can be used to account for this effect. However for proton dosimetry the dose response of films exhibits an additional dependence because of the variation of the linear energy transfer (LET) as the protons penetrate matter. In the present study, we hypothesized that the dose response for EBT2 films can be mathematically described as a bimolecular chemical reaction. Furthermore, we have shown that the LET effect can be incorporated in the dose-response curve. A set of EBT2 films was exposed to pristine 161.6 MeV proton beams. The films were exposed to doses ranging from 0.93 to 14.82 Gy at a depth of 2 cm in water. The procedure was repeated with one film exposed to a lower energy beam (85.6 MeV). We also computed the LET and dose to water in the sensitive layer of the films with a validated Monte Carlo system, taking into account the film construction (polyester, adhesive and sensitive layers). The bimolecular model was able to accurately fit the experimental data with a correlation factor of 0.9998, and the LET correction factor was determined and incorporated into the dose-response function. We also concluded that the film orientation is important when determining the LET correction factor because of the asymmetric construction of the film.

  18. Measurements of SNAC2 area dosimeters placed in different configurations around the PROSPERO reactor and comparison with TRIPOLI-4 calculations

    Energy Technology Data Exchange (ETDEWEB)

    Rousseau, G.; Chambru, L.; Authier, N. [CEA, Centre de Valduc, 21120 Is-sur-Tille, (France)

    2015-07-01

    In the context of criticality accident alarm system tests, several experiments were carried out in 2013 on the PROSPERO reactor to study the response to neutron and gamma of different devices and dosimeters, particularly on the SNAC2 dosimeter. This article presents the results of this criticality dosimeter in different configurations, and compares the experimental measurements with the results of calculation performed with the TRIPOLI-4 Monte-Carlo Neutral Particles transport code. PROSPERO is a metallic critical assembly managed by the Criticality, Neutron Science and Measurement Department located at the French CEA Research Center of Valduc. The core, surrounded by a reflector of depleted uranium, is composed of 2 horizontal cylindrical blocks made of a highly enriched uranium alloy which can be placed in contact, and of 4 depleted uranium control rods which allow the reactor to be driven. This reactor, placed in a cell 10 m x 8 m x 6 m high, with 1.4-meter-thick concrete walls, is used as a fast neutron spectrum source and is operated at stable power level in delayed critical state, which can vary from 3 mW to 3 kW. PROSPERO is extensively used for electronic hardening or to study the effect of the neutrons on various materials. The SNAC2 criticality dosimeter is a zone dosimeter allowing the off line measurement of criticality accident neutron doses. This dosimeter consists of the pile up of seven activation foils embedded into a 23 mm diameter x 21 mm height cadmium container. The activation measurement of each foil, using a gamma spectroscopy technique, gives information about the neutron reaction rates. The SNAC2 software allows the spectrum unfolding from these values, taking into account the hypothesis of a particular spectrum shape, in three components: a Maxwell spectrum component for the thermal range, a 1/E component for the epithermal range, and a Watt spectrum component for the high energy range. Moreover, from the neutron spectrum, the SNAC

  19. Thermal response of transparent silver nanowire/PEDOT:PSS film heaters.

    Science.gov (United States)

    Ji, Shulin; He, Weiwei; Wang, Ke; Ran, Yunxia; Ye, Changhui

    2014-12-10

    Thermal response behavior of transparent silver nanowire/PEDOT:PSS film heaters are intensively studied for manipulating heating temperature, response time, and power consumption. Influences of substrate heat capacity, heat transfer coefficient between air and heater, sheet resistance and dimension of Ag nanowire film, on the thermal response are investigated from thermodynamic analysis. Suggestion is given for practical applications that if other parameters are fixed, Ag nanowire coverage can be utilized as an effective parameter to adjust the thermal response. The heat transfer coefficient plays opposite roles on thermal response speed and achievable steady temperature. A value of ≈32 W m(-2) K(-1) is obtained from transient process analysis after correcting it by considering heater resistance variation during heating tests. Guidance of designing heaters with a given response time is provided by forming Ag nanowire film with a suitable sheet resistance on substrate of appropriate material and a certain thickness. Thermal response tests of designed Ag heaters are performed to show higher heating temperature, shorter response time, and lower power consumption (179 °C cm(2) W(-1)) than ITO/FTO heaters, as well as homogeneous temperature distribution and stability for repeated use. Potential applications of the Ag heaters in window defogging, sensing and thermochromism are manifested.

  20. Multi-Stimuli-Responsive Polymer Materials: Particles, Films, and Bulk Gels.

    Science.gov (United States)

    Cao, Zi-Quan; Wang, Guo-Jie

    2016-06-01

    Stimuli-responsive polymers have received tremendous attention from scientists and engineers for several decades due to the wide applications of these smart materials in biotechnology and nanotechnology. Driven by the complex functions of living systems, multi-stimuli-responsive polymer materials have been designed and developed in recent years. Compared with conventional single- or dual-stimuli-based polymer materials, multi-stimuli-responsive polymer materials would be more intriguing since more functions and finer modulations can be achieved through more parameters. This critical review highlights the recent advances in this area and focuses on three types of multi-stimuli-responsive polymer materials, namely, multi-stimuli-responsive particles (micelles, micro/nanogels, vesicles, and hybrid particles), multi-stimuli-responsive films (polymer brushes, layer-by-layer polymer films, and porous membranes), and multi-stimuli-responsive bulk gels (hydrogels, organogels, and metallogels) from recent publications. Various stimuli, such as light, temperature, pH, reduction/oxidation, enzymes, ions, glucose, ultrasound, magnetic fields, mechanical stress, solvent, voltage, and electrochemistry, have been combined to switch the functions of polymers. The polymer design, preparation, and function of multi-stimuli-responsive particles, films, and bulk gels are comprehensively discussed here.

  1. Comparison of Energy Dependence of PAGAT Polymer Gel Dosimeter with Electron and Photon Beams using Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    B. Azadbakht

    2012-02-01

    Full Text Available The purpose of this study was to evaluate dependence of PAGAT polymer gel dosimeter 1/T2 on different electron and photon energies for a standard clinically used 60Co therapy unit and an electa linear accelerator.Using MRI, the formulation to give the maximum change in the transverse relaxation rate R2(1/T2 was determined to be 4.5% N,N'-methylen-bis-acrylamide(bis, 4.5% acrylamid(AA, 5% gelatine, 5 mM tetrakis (hydroxymethyl phosphonium chloride (THPC, 0.01 mM hydroquinone (HQ and 86% HPLC(Water. When the preparation of final polymer gel solution is completed, it is transferred into phantoms and allowed to set by storage in a refrigerator at about 4°C. The optimal post-manufacture irradiation and post imaging times were both determined to be 24 h. The sensitivity of PAGAT polymer gel dosimeter with irradiation of photon and electron beams was represented by the slope of calibration curve in the linear region measured for each modality. The response of PAGAT gel with photon and electron beams is very similar in the lower dose region. The R2-dose response was linear up to 30 Gy and the R2-dose response of the PAGAT polymer gel dosimeter is linear between 10 to 30 Gy. In electron beams the R2-dose response for doses less than 3 Gy is not exact, but in photon beams the R2-dose response for doses less than 2Gy is not exact. Dosimeter energy dependence was studied for electron energies of 4, 12 and 18MeV and photon energies of 1.25, 4, 6 and 18 MV. Evaluation of dosimeters were performed on Siemens Symphony, Germany 1.5T Scanner in the head coil. In this study no trend in polymer-gel dosimeter 1/T2 dependence was found on mean energy for electron and photon beams.

  2. Recall of Personal Dosimeters Not Presently in Use

    CERN Multimedia

    SC Unit

    2008-01-01

    The Dosimetry Service requests all persons who do not require access to radiation areas in the foreseeable future to return their personal dosimeter to the Dosimetry Service. This concerns, for example, experimental physicists whose beam time is over until 2009, or persons whose work profile has changed and therefore no longer need regular access to radiation areas. When regular access to radiation areas is needed again at a later date, a new dosimeter can be attributed if the prerequisites (medical fitness certificate, RP course) are met. This recall will allow personal dosimeters to be attributed to personnel who will soon be working in newly created radiation areas at the LHC. Thank you for your understanding and collaboration. Thomas Otto on behalf of the Dosimetry Service Radiation Protection Group

  3. Monitoring of environmental UV radiation by biological dosimeters.

    Science.gov (United States)

    Ronto, G; Berces, A; Grof, P; Fekete, A; Kerekgyarto, T; Gaspar, S; Stick, C

    2000-01-01

    As a consequence of the stratospheric ozone layer depletion biological systems can be damaged due to increased UV-B radiation. The aim of biological dosimetry is to establish a quantitative basis for the risk assessment of the biosphere. DNA is the most important target molecule of biological systems having special sensitivity against short wavelength components of the environmental radiation. Biological dosimeters are usually simple organisms, or components of them, modeling the cellular DNA. Phage T7 and polycrystalline uracil biological dosimeters have been developed and used in our laboratory for monitoring the environmental radiation in different radiation conditions (from the polar to equatorial regions). Comparisons with Robertson-Berger (RB) meter data, as well as with model calculation data weighted by the corresponding spectral sensitivities of the dosimeters are presented. Suggestion is given how to determine the trend of the increase in the biological risk due to ozone depletion. c2001 COSPAR Published by Elsevier Science Ltd. All rights reserved.

  4. Atomistic modeling of electron relaxation effect on femtosecond laser-induced thermoelastic response of gold films

    Science.gov (United States)

    Xiong, Q. L.; Tian, X. G.; Lu, T. J.

    2012-07-01

    The thermoelastic response of thin gold films induced by femtosecond laser irradiation is numerically simulated using a modified combined two-temperature model (TTM) and molecular dynamics (MD) method, with focus placed upon the influence of the electron relaxation effect. The validity of the numerical approach is checked against existing experimental results. While the electron relaxation effect is found negligible when the laser duration is much longer than the electron thermal relaxation time, it becomes significant if the laser duration matches the electron relaxation time, especially when the former is much shorter than the latter. The characteristics of thermo-mechanical interaction in the thin film are analyzed, and the influence of temperature-dependent material properties upon the thermoelastic response of the film quantified.

  5. Multiscale numerical study on ferroelectric nonlinear response of PZT thin films (Conference Presentation)

    Science.gov (United States)

    Wakabayashi, Hiroki; Uetsuji, Yasutomo; Tsuchiya, Kazuyoshi

    2017-06-01

    PZT thin films have excellent performance in deformation precision and response speed, so it is used widely for actuators and sensors of Micro Electro Mechanical System (MEMS). Although PZT thin films outputs large piezoelectricity at morphotropic phase bounfary (MPB), it shows a complicated hysteresis behavior caused by domain switching and structural phase transition between tetragonal and rhombohedral. In general, PZT thin films have some characteristic crystal morphologies. Additionally mechanical strains occur by lattice mismatch with substrate. Therefore it is important for fabrication and performance improvement of PZT thin films to understand the relation between macroscopic hysteresis response and microstructural changes. In this study, a multiscale nonlinear finite element simulation was proposed for PZT thin films at morphotropic phase boundary (MPB) on the substrate. The homogenization theory was employed for scale-bridging between macrostructure and microstructure. Figure 1 shows the proposed multiscale nonlinear simulation [1-3] based on the homogenization theory. Macrostructure is a homogeneous structure to catch the whole behaviors of actuators and sensors. And microstructure is a periodic inhomogeneous structure consisting of domains and grains. Macrostructure and microstructure are connected perfectly by homogenization theory and are analyzed by finite element method. We utilized an incremental form of fundamental constitutive law in consideration with physical property change caused by domain switching and structural phase transition. The developed multiscale finite element method was applied to PZT thin films with lattice mismatch strain on the substrate, and the relation between the macroscopic hysteresis response and microscopic domain switching and structural phase transition were investigated. Especially, we discuss about the effect of crystal morphologies and lattice mismatch strain on hysteresis response.

  6. Monte Carlo simulation experiments on box-type radon dosimeter

    Science.gov (United States)

    Jamil, Khalid; Kamran, Muhammad; Illahi, Ahsan; Manzoor, Shahid

    2014-11-01

    Epidemiological studies show that inhalation of radon gas (222Rn) may be carcinogenic especially to mine workers, people living in closed indoor energy conserved environments and underground dwellers. It is, therefore, of paramount importance to measure the 222Rn concentrations (Bq/m3) in indoors environments. For this purpose, box-type passive radon dosimeters employing ion track detector like CR-39 are widely used. Fraction of the number of radon alphas emitted in the volume of the box type dosimeter resulting in latent track formation on CR-39 is the latent track registration efficiency. Latent track registration efficiency is ultimately required to evaluate the radon concentration which consequently determines the effective dose and the radiological hazards. In this research, Monte Carlo simulation experiments were carried out to study the alpha latent track registration efficiency for box type radon dosimeter as a function of dosimeter's dimensions and range of alpha particles in air. Two different self developed Monte Carlo simulation techniques were employed namely: (a) Surface ratio (SURA) method and (b) Ray hitting (RAHI) method. Monte Carlo simulation experiments revealed that there are two types of efficiencies i.e. intrinsic efficiency (ηint) and alpha hit efficiency (ηhit). The ηint depends upon only on the dimensions of the dosimeter and ηhit depends both upon dimensions of the dosimeter and range of the alpha particles. The total latent track registration efficiency is the product of both intrinsic and hit efficiencies. It has been concluded that if diagonal length of box type dosimeter is kept smaller than the range of alpha particle then hit efficiency is achieved as 100%. Nevertheless the intrinsic efficiency keeps playing its role. The Monte Carlo simulation experimental results have been found helpful to understand the intricate track registration mechanisms in the box type dosimeter. This paper explains that how radon concentration from the

  7. Measurement of a PAGAT gel dosimeter by ultrasound computed tomography

    Science.gov (United States)

    Khoei, S.; Trapp, J. V.; Langton, C. M.

    2013-06-01

    In this work we used a 3D quantitative CT ultrasound imaging system to characterise polymer gel dosimeters. The system comprised of two identical 5 MHz 128 element phased-array ultrasound transducers co-axially aligned and submerged in water as a coupling agent. Rotational and translational movement of the gel dosimeter sample between the transducers were performed using a robotic arm. Ultrasound signals were generated and received using an Olympus Omniscan unit. Dose sensitivity of attenuation and time of flight ultrasonic parameters were assessed using this system.

  8. The dosimetric characteristics of personal alarm dosimeter : Dependence of dose rate and photon energy

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Ha-Seok; Lee, Jun Hee; Kim, Jae Min; Song, Gi Chang; Park, Jae Duck [Iljin Radiation Engineering Co. Ltd., Hwaseong (Korea, Republic of)

    2015-10-15

    There is a need to accurately measure the radiation dose. The dosimeters such as TLD(main dosimeter) are cumulative personal dosimeter to be measured after the radiation exposure, not provide information in real-time personal dose. Therefore, active dosimeter such as electronic personal dosimeters have used together as an alternative dosimeter to manage radiation dose of worker in the work place. We have developed and produced electronic personal dosimeters using photo diode as a detector(Model name: CLOVER), have also programmed the dose calculating algorithms to fit this dosimeter. We have developed and produced electronic personal dosimeters using photo diode as a detector, have also programmed the dose calculating algorithms to fit this dosimeter. The result of tests to meet in KS C IEC 61526 requirements for this dosimeter could obtain the following conclusions. 3.1. The relative intrinsic error and the dependence of dose equivalent rate of this electronic dosimeter are not exceed 20%, and meet with requirements. 3.2. The dependence of energy in the low energy region is exceeded 30%.

  9. Cortisol response and psychological distress predict susceptibility to false memories for a trauma film.

    Science.gov (United States)

    Monds, Lauren A; Paterson, Helen M; Ali, Sinan; Kemp, Richard I; Bryant, Richard A; McGregor, Iain S

    2016-10-01

    For eyewitness testimony to be considered reliable, it is important to ensure memory remains accurate following the event. As many testimonies involve traumatic, as opposed to neutral, events, it is important to consider the role of distress in susceptibility to false memories. The aim of this study was to investigate whether cortisol response following a stressor would be associated with susceptibility to false memories. Psychological distress responses were also investigated, specifically, dissociation, intrusions, and avoidance. Participants were allocated to one of three conditions: those who viewed a neutral film (N = 35), those who viewed a real trauma film (N = 35), and a trauma "reappraisal" group where participants were told the film was not real (N = 35). All received misinformation about the film in the form of a narrative. Participants provided saliva samples (to assess cortisol) and completed distress and memory questionnaires. Cortisol response was a significant predictor of the misinformation effect. Dissociation and avoidance were related to confabulations. In conclusion, following a stressor an individual may differ with regard to their psychological response to the event, and also whether they experience a cortisol increase. This may affect whether they are more distressed later on, and also whether they remember the event accurately.

  10. Thinning identification technique using stainless steel film heater and response surface method

    Science.gov (United States)

    Ogasawara, Nagahisa; Yamada, Hiroyuki

    2011-05-01

    The infrared thermography has not been widely applied to nondestructive inspection for metals. It is because the metal emissivity is too low to be measured the temperature. To make up for this disadvantage, a new heating technique using a stainless steel film was proposed and a nondestructive inspection system with the response surface method was developed. The stainless film has a high electric resistance and generates large Joule heat. Its response is quick and the quantity of heat is easily controlled. Moreover, the film has a high enough thermal conductivity, therefore a black painted film can be a blackbody surface of metal structures. Consequently IR camera can easily measure the metal temperature accurately. The nondestructive inspection system that can quantitatively identify geometrical parameters of a local thinning was developed. The system consists of a forward analysis and an inverse analysis. In the forward analysis, the response surface that shows a relationship between geometrical parameters and characteristic values is built by experimental design method. In the inverse analysis, substituting the characteristic values into the response surface, the geometrical parameters are finally identified. The inspection system can identify the local thinning shape robustly by selecting the attribute for the shape parameters.

  11. The study on optically stimulated luminescence dosimeter based on the SrS:Eu, Sm and CaS:Eu, Sm

    Institute of Scientific and Technical Information of China (English)

    Liu Yan-Ping; Chen Zhao-Yang; Fan Yan-Wei; Ba Wei-Zhen; Gou Qi; Lu Wu; Tang Xin-Qiang; Du Yan-Zhao

    2008-01-01

    With the increasing use of nuclear energy, there is a need for a wider range of efficient dosimeters for radiation detection and assessment. There has been a tremendous growth in the development of radiation detectors and devices in the past few decades. In recent years, the development of new materials for radiation dosimetry has progressed significantly. Alkaline earth sulfides (AES) have been known for a long time as excellent and versatile phosphor materials.In the present investigation, a number of phosphor samples such as mono-, binary and ternary sulfides of alkaline earths (Ⅱa-Ⅵb) have been prepared and their TL properties have been studied with respect to exposure (x-ray) response and fading. In this paper, some results on SrS:Eu, Sm and CaS:Eu, Sm phosphors are presented. A type of novel OSL dosimeter is described. The dosimeter takes advantage of the characteristics of charge trapping materials SrS:Eu, Sm and CaS:Eu, Sm that exhibit optically stimulated luminescence (OSL). The measuring range of the dosimeter is from 0.01 to 1000 Gy. The OSL dosimeters provide capability for remote monitoring radiation locations which are difficult to access and hazardous. This equipment is relatively simple, small in size and has low power consumption. The device is suitable for space radiation dose exploration. In addition, it also can be used in IC and other radiation occasions and has good prospects.

  12. Reduced graphene oxide film based highly responsive infrared detector

    Science.gov (United States)

    Khan, Mustaque A.; Nanda, Karuna K.; Krupanidhi, Saluru B.

    2017-08-01

    Due to the unique optical properties, graphene can effectively be used for the detection of infrared light. In this regard, reduced graphene oxide (RGO) has drawn considerable attention in scientific society because of simplicity of preparation and tunable properties. Here, we report the synthesis of RGO by solvothermal reduction of graphene oxide (GO) in ethanol and the detection of infrared light (1064 and 1550 nm) with metal—RGO—metal configuration. We have observed that photocurrent, responsivity as well as the external quantum efficiency increase with C/O ratio. The responsivity value in near-infrared region can be as high as 1.34 A · W-1 and the external quantum efficiency is more than 100%. Response times of these devices are in the order of few seconds. Overall, the responsivity of our device is found to be better than many of the already reported values where graphene or reduced graphene oxide is the only active material. The high value of quantum efficiency is due to strong light absorption and the presence of mid-gap states band in RGOs.

  13. pH-responsive layer-by-layer films of zwitterionic block copolymer micelles

    OpenAIRE

    Demirel, Adem Levent; Yusan, Pelin; Tuncel, İrem; Bütün, Vural; Erel-Goktepe, İrem

    2014-01-01

    We report a strategy to incorporate micelles of poly[3-dimethyl (methacryloyloxyethyl) ammonium propane sulfonate]-block-poly[2-(diisopropylamino) ethyl methacrylate] (beta PDMA-b-PDPA) into electrostatic layer-by-layer (LbL) films. We obtained micelles with pH-responsive PDPA-cores and zwitterionic bPDMA-coronae at pH 8.5 through pH-induced self-assembly of bPDMA-b-PDPA in aqueous solution. To incorporate bPDMA-b-PDPA micelles into LbL films, we first obtained a net electrical charge on bPDM...

  14. Dielectric response and novel electromagnetic modes in three-dimensional Dirac semimetal films

    Science.gov (United States)

    Kotov, O. V.; Lozovik, Yu. E.

    2016-06-01

    Using the Kubo formalism we have calculated the local dynamic conductivity of a bulk, i.e., three-dimensional (3D), Dirac semimetal (BDS). We obtain that at frequencies lower than Fermi energy the metallic response in a BDS film manifests in the existence of surface-plasmon polaritons, but at higher frequencies the dielectric response is dominated and it occurs that a BDS film behaves as a dielectric waveguide. At this dielectric regime we predict the existence inside a BDS film of novel electromagnetic modes, a 3D analog of the transverse electric waves in graphene. We also find that the dielectric response manifests as the wide-angle passband in the mid-infrared (IR) transmission spectrum of light incident on a BDS film, which can be used for the interferenceless omnidirectional mid-IR filtering. The tuning of the Fermi level of the system allows us to switch between the metallic and the dielectric regimes and to change the frequency range of the predicted modes. This makes BDSs promising materials for photonics and plasmonics.

  15. Charged vacancy induced enhanced piezoelectric response of reactive assistive IBSD grown AlN thin films

    Science.gov (United States)

    Sharma, Neha; Rath, Martando; Ilango, S.; Ravindran, T. R.; Ramachandra Rao, M. S.; Dash, S.; Tyagi, A. K.

    2017-01-01

    Piezoelectric response of AlN thin films was investigated in a AlN/Ti/Si(1 0 0) layer structure prepared by ion beam sputter deposition (IBSD) in reactive assistance of N+/\\text{N}2+ ions. The samples were characterized for their microstructure, piezoelectric response and charged defects using high resolution x-ray diffraction (HR-XRD), piezo force microscopy (PFM) and photoluminescence (PL) spectroscopy respectively. Our results show that the films are highly textured along the a-axis and charged native point defects are present in the microstructure. Phase images of these samples obtained from PFM show that the films are predominantly N-polar. The measured values of piezoelectric coefficient d 33(eff) for these samples are as high as 206  ±  20 pm V-1 and 668  ±  60 pm V-1 calculated by piezo response loop for AlN films of a thickness of 235 nm and 294 nm respectively. A mechanism for high d 33(eff) values is proposed with a suitable model based on the charged defects induced enhanced polarization in the dielectric continuum of AlN.

  16. A study on the applicability of solid state, real-time dosimeters to the CMS experiment at the large hadron collider

    Energy Technology Data Exchange (ETDEWEB)

    Camanzi, B. E-mail: barbara.camanzi@cern.ch; Glaser, M.; Tsesmelis, E.; Adams, L. E-mail: ladams@aldeburgh.demon.co.uk

    2003-03-11

    MOSFET dosimeters have been exposed to a large range of radiation fields: 192 MeV positive pions, 500 MeV electrons, 23 GeV protons and a wide energy-spectrum of neutrons. This is the first time that pion dosimetry with MOSFETs is presented. The response curves of the devices are given, together with an evaluation of their dynamic range, showing that these dosimeters can be successfully used to monitor radiation fields up to very high doses and fluences. In the 500 MeV electron beam, an irradiation of p{sup +}/n/n{sup +} diodes together with MOSFETs was also performed. The results of this irradiation show that both types of dosimeters can be used in CMS to monitor in real time the radiation environment.

  17. A study on the applicability of solid state, real-time dosimeters to the CMS experiment at the large hadron collider

    Science.gov (United States)

    Camanzi, B.; Glaser, M.; Tsesmelis, E.; Adams, L.

    2003-03-01

    MOSFET dosimeters have been exposed to a large range of radiation fields: 192 MeV positive pions, 500 MeV electrons, 23 GeV protons and a wide energy-spectrum of neutrons. This is the first time that pion dosimetry with MOSFETs is presented. The response curves of the devices are given, together with an evaluation of their dynamic range, showing that these dosimeters can be successfully used to monitor radiation fields up to very high doses and fluences. In the 500 MeV electron beam, an irradiation of p +/n/n + diodes together with MOSFETs was also performed. The results of this irradiation show that both types of dosimeters can be used in CMS to monitor in real time the radiation environment.

  18. Activation of Dosimeters Used in qa of Medical Linear Accelerators

    Science.gov (United States)

    Polaczek-Grelik, Kinga; Nowacka, Magdalena; Raczkowski, Maciej

    2017-09-01

    This paper presents the first results of a project intended to investigate γ-radiation activity induced in dosimeters used in clinical practice during routine quality assurance of high-energy photon beams emitted by electron linear accelerators. Two aspects of the activation via photonuclear reactions (X, n) of therapeutic beam and subsequent capture of secondary neutrons (n,γ) are under considerations: the influence of activation on intrinsic background of the dosimeters and exposure of dosimetrists who operate this equipment. The activation of several types of ionization chambers as well as the silicon diodes was studied after long-time exposure (10 000 MUs) of the 15 MV photon beam (Elekta Synergy). Photon fluxes obtained from spectra of γ-rays registered by HPGe spectrometer were subsequently converted to equivalent doses using appropriate coefficients. The main contribution to the induced activity comes from the neutron capture process on Al, Mn and Cu, therefore it decays quite fast with the half-lives of the order of 15 minutes. Nevertheless, the activation of chlorine was also observed. The estimated equivalent doses to skin and eye lens were in the range 0.19 - 0.62 μSv/min. However, no influence on intrinsic background signal of all studied dosimeters was observed. The preliminary results indicate that induced radioactivity of dosimeters is strongly influenced by therapeutic beam quality and neutron source strength of particular linac. This dependence will be studied deeper in order to quantify it more precisely.

  19. Validation of an Innovative Satellite-Based UV Dosimeter

    Science.gov (United States)

    Morelli, Marco; Masini, Andrea; Simeone, Emilio; Khazova, Marina

    2016-08-01

    We present an innovative satellite-based UV (ultraviolet) radiation dosimeter with a mobile app interface that has been validated by exploiting both ground-based measurements and an in-vivo assessment of the erythemal effects on some volunteers having a controlled exposure to solar radiation.Both validations showed that the satellite-based UV dosimeter has a good accuracy and reliability needed for health-related applications.The app with this satellite-based UV dosimeter also includes other related functionalities such as the provision of safe sun exposure time updated in real-time and end exposure visual/sound alert. This app will be launched on the global market by siHealth Ltd in May 2016 under the name of "HappySun" and available both for Android and for iOS devices (more info on http://www.happysun.co.uk).Extensive R&D activities are on-going for further improvement of the satellite-based UV dosimeter's accuracy.

  20. Maximizing the dielectric response of molecular thin films via quantum chemical design.

    Science.gov (United States)

    Heitzer, Henry M; Marks, Tobin J; Ratner, Mark A

    2014-12-23

    Developing high-capacitance organic gate dielectrics is critical for advances in electronic circuitry based on unconventional semiconductors. While high-dielectric constant molecular substances are known, the mechanism of dielectric response and the fundamental chemical design principles are not well understood. Using a plane-wave density functional theory formalism, we show that it is possible to map the atomic-scale dielectric profiles of molecule-based materials while capturing important bulk characteristics. For molecular films, this approach reveals how basic materials properties such as surface coverage density, molecular tilt angle, and π-system planarity can dramatically influence dielectric response. Additionally, relatively modest molecular backbone and substituent variations can be employed to substantially enhance film dielectric response. For dense surface coverages and proper molecular alignment, conjugated hydrocarbon chains can achieve dielectric constants of >8.0, more than 3 times that of analogous saturated chains, ∼2.5. However, this conjugation-related dielectric enhancement depends on proper molecular orientation and planarization, with enhancements up to 60% for proper molecular alignment with the applied field and an additional 30% for conformations such as coplanarity in extended π-systems. Conjugation length is not the only determinant of dielectric response, and appended polarizable high-Z substituents can increase molecular film response more than 2-fold, affording estimated capacitances of >9.0 μF/cm2. However, in large π-systems, polar substituent effects are substantially attenuated.

  1. Monte Carlo simulation experiments on box-type radon dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Jamil, Khalid, E-mail: kjamil@comsats.edu.pk; Kamran, Muhammad; Illahi, Ahsan; Manzoor, Shahid

    2014-11-11

    Epidemiological studies show that inhalation of radon gas ({sup 222}Rn) may be carcinogenic especially to mine workers, people living in closed indoor energy conserved environments and underground dwellers. It is, therefore, of paramount importance to measure the {sup 222}Rn concentrations (Bq/m{sup 3}) in indoors environments. For this purpose, box-type passive radon dosimeters employing ion track detector like CR-39 are widely used. Fraction of the number of radon alphas emitted in the volume of the box type dosimeter resulting in latent track formation on CR-39 is the latent track registration efficiency. Latent track registration efficiency is ultimately required to evaluate the radon concentration which consequently determines the effective dose and the radiological hazards. In this research, Monte Carlo simulation experiments were carried out to study the alpha latent track registration efficiency for box type radon dosimeter as a function of dosimeter’s dimensions and range of alpha particles in air. Two different self developed Monte Carlo simulation techniques were employed namely: (a) Surface ratio (SURA) method and (b) Ray hitting (RAHI) method. Monte Carlo simulation experiments revealed that there are two types of efficiencies i.e. intrinsic efficiency (η{sub int}) and alpha hit efficiency (η{sub hit}). The η{sub int} depends upon only on the dimensions of the dosimeter and η{sub hit} depends both upon dimensions of the dosimeter and range of the alpha particles. The total latent track registration efficiency is the product of both intrinsic and hit efficiencies. It has been concluded that if diagonal length of box type dosimeter is kept smaller than the range of alpha particle then hit efficiency is achieved as 100%. Nevertheless the intrinsic efficiency keeps playing its role. The Monte Carlo simulation experimental results have been found helpful to understand the intricate track registration mechanisms in the box type dosimeter. This paper

  2. Polyurethane Dispersions with Peptide Corona: Facile Synthesis of Stimuli-Responsive Dispersions and Films.

    Science.gov (United States)

    Breucker, Laura; Schöttler, Susanne; Landfester, Katharina; Taden, Andreas

    2015-08-10

    Peptide-polymer hybrid particles of submicron size yielding stimuli-responsive macroscopic films are presented. A thermoplastic polyurethane (PU) carrying polysiloxane and polyester soft segments serves as core material to obtain flexible, yet semicrystalline films with temperature-sensitivity. The synthesis is based on the high-sheer emulsification of isocyanate-terminated PU prepolymers, which in our model system purposefully lack any ability of colloidal self-stabilization. While emulsification in water leads to immediate coagulation, stable dispersions of polyurethane nanoparticles were formed in aqueous solutions of a hydrolyzed protein from wool. A comparison of dispersion and film properties to nonreactive, otherwise identical dispersions suggests covalent attachment of the peptide to the PU backbone. We show that the colloidal stability of the hybrid particles is completely governed by the peptide corona, and hence pH-triggered coagulation can be employed to induce particle deposition and film formation. Differential scanning calorimetry confirms partial crystallinity in the film and reveals strongly modified crystallization behavior due to the peptide.

  3. Enhanced optical and nonlinear optical responses in a polyelectrolyte templated Langmuir-Blodgett film.

    Science.gov (United States)

    Rajesh, K; Balaswamy, B; Yamamoto, K; Yamaki, H; Kawamata, J; Radhakrishnan, T P

    2011-02-01

    Optical and nonlinear optical properties like fluorescence and second harmonic generation (SHG) of molecular materials can be strongly influenced by the mode of assembly of the molecules. The Langmuir-Blodgett (LB) technique is an elegant route to the controlled assembly of molecules in ultrathin films, and complexation of ionic amphiphiles in the Langmuir film by polyions introduced in the aqueous subphase provides a simple and efficient access to further control, stabilization, and optimization. The monolayer LB film of the hemicyanine-based amphiphile, N-n-octadecyl-4-[2-(4-(N,N-ethyloctadecylamino)phenyl)ethenyl]pyridinium possessing a "tail-head-tail" structure, shows fluorescence as well as SHG response. The concomitant enhancement of both of these linear and nonlinear optical attributes is achieved through templating with the polyanion of carboxymethylcellulose. Brewster angle and atomic force microscopy reveal the influence of polyelectrolyte templating on the morphology of the Langmuir and LB films. Polarized absorption and fluorescence spectroscopy provide insight into the impact of complexation with the polyelectrolyte on the orientation and deaggregation of the hemicyanine headgroup leading to fluorescence and SHG enhancement in the LB film.

  4. a Thermally Desorbable Miniature Passive Dosimeter for Organic Vapors

    Science.gov (United States)

    Gonzalez, Jesus Antonio

    A thermally desorbable miniature passive dosimeter (MPD) for organic vapors has been developed in conformity with theoretical and practical aspects of passive dosimeter design. The device was optimized for low sample loadings resulting from short-term and/or low concentration level exposure. This was accomplished by the use of thermal desorption rather than solvent elution, which provided the GC method with significantly higher sensitivity. Laboratory evaluation of this device for factors critical to the performance of passive dosimeters using benzene as the test vapor included: desorption efficiency (97.2%), capacity (1400 ppm-min), sensitivity (7ng/sample or 0.06 ppmv for 15 minutes sampling) accuracy and precision, concentration level, environmental conditions (i.e., air face velocity, relative humidity) and sample stability during short (15 minutes) and long periods of time (15 days). This device has demonstrated that its overall accuracy meets NIOSH and OSHA requirements for a sampling and analytical method for the exposure concentration range of 0.1 to 50 ppm (v/v) and 15 minutes exposures. It was demonstrated that the MPD operates in accordance with theoretically predicted performance and should be adequate for short-term and/or low concentration exposure monitoring of organic vapors in the workplace. In addition a dynamic vapor exposure evaluation system for passive dosimeters have been validated using benzene as the test vapor. The system is capable of generating well defined short-square wave concentration profiles suitable for the evaluation of passive dosimeters for ceiling exposure monitoring.

  5. Investigation of the dose characteristics of an n-NIPAM gel dosimeter with computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Kuan-Yu [Department of Orthopedic Surgery, Mackay Memorial Hospital Taitung Branch, Taitung, Taiwan (China); Shih, Tian-Yu [Department of Radiology, Cheng Ching Hospital at Chung Kang, Taichung, Taiwan (China); Institute of Radiological Science, Central Taiwan University of Science and Technology, No. 11, Pu-Tzu Lane, Pei-tun District, 40601 Taichung, Taiwan (China); Hsieh, Bor-Tsung [Institute of Radiological Science, Central Taiwan University of Science and Technology, No. 11, Pu-Tzu Lane, Pei-tun District, 40601 Taichung, Taiwan (China); Chang, Shu-Jun [Health Physics Division, Institute of Nuclear Energy Research, Taoyuan, Taiwan (China); Liu, Yan-Lin [Institute of Radiological Science, Central Taiwan University of Science and Technology, No. 11, Pu-Tzu Lane, Pei-tun District, 40601 Taichung, Taiwan (China); Wu, Tung-Hsin [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan (China); Wu, Jay, E-mail: jwu@ctust.edu.tw [Institute of Radiological Science, Central Taiwan University of Science and Technology, No. 11, Pu-Tzu Lane, Pei-tun District, 40601 Taichung, Taiwan (China)

    2011-10-01

    Nowadays, radiotherapy attempts to deliver complex three-dimensional (3-D) dose distribution. The gel dosimeter, which can measure the 3-D dose output, is suitable for clinical use. This study developed an n-NIPAM gel dosimeter based on an N-isopropyl-acrylamide monomer, and used computed tomography (CT) to evaluate the characteristics of n-NIPAM gels. The n-NIPAM gel consisted of 6% gelatin, 5% monomer, and 2.5% cross-linker combined with 5 mM tetrakis (hydroxymethyl) phosphonium chloride (THPC) for deoxygenation. Dose responses of 2-15 Gy delivered by a linear accelerator were examined. Temporal instability, energy dependence, dose rate dependence, and spatial resolution were evaluated as well. Temporal instability appeared before 24 h post-irradiation. The maximum difference of sensitivity reached 33% for various dose rates from 100 to 500 cGy min{sup -1}, while it was within 10% for X-ray energies from 6 to 15 MV. The average sensitivity of n-NIPAM under 6 MV and 400 cGy min{sup -1} was 0.5689 HU Gy{sup -1}, and the linearity (R{sup 2}=0.998) was comparable to that of the conventional NIPAM gels. For the spatial resolution, the edge spread distances were generally shorter than 6.5 mm for adjacent quadrants with different dose gradients of 5/10, 5/15, 10/20, and 15/20 Gy. We conclude that n-NIPAM has high linearity and high sensitivity. Although the energy dependence is minor, there is a slight dose rate dependence. The proposed dosimeter with CT readout is suitable in clinical radiotherapy to increase the accuracy of dose verification.

  6. Characterization of Fricke dosimeter developed at Centro Regional de Ciencias Nucleares, Recife, PE, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Vivianne L.B.; Cunha, Manuela S.; Santos, Carla D.A.; Figueiredo, Marcela D.C.; Rodrigues, Kelia R.G.; Melo, Roberto T.; Hazin, Clovis A., E-mail: vlsouza@cnen.gov.b, E-mail: manusc06@hotmail.co, E-mail: daysebutterfly@hotmail.co, E-mail: keliareja@hotmail.co, E-mail: rtmelo@cnen.gov.b, E-mail: chazin@cnen.gov.b [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2009-07-01

    Fricke Xylenol Gel (FXG) is a modified Fricke dosimeter system that was tested at the Centro Regional de Ciencias Nucleares (CRCN/CNEN), in Recife, Brazil. The Fricke dosimeter system has been used in our laboratory successfully. We decided to test the FXG in our laboratory because this dosimetric system presents some advantages in relation to the Fricke dosimeter, such as: easy preparation, more sensitivity for doses between 5 - 30 Gy, good reproducibility, tissue equivalence and multidimensional dose information. The dosimetric solution was synthesized with 0.392 g of ferrous ammonium sulphate, 0.0060 g of sodium chloride, 0.0076 g of xylenol orange, 5.0 g of gelatine (270 bloom porcine) and 300 mul of sulphuric acid in 100 ml of water. First, the water-gelatin mixture was heated and continuously stirred with a magnetic stirrer while the others reagents were added and the temperature was raised to 45 deg C. Once the solution ready it was transferred to acrylic cuvettes and kept in dark under refrigeration at 5 deg C during 12 h. Characteristics such as absorption spectrum, stability and linearity were evaluated by spectrophotometry (Beckman DU-640 UV-visible spectrophotometer). The developed material presented a good performance: ferric ion concentration at 589 nm, after irradiation; linear dose-response curve between 5 and 30 Gy; and saturation region for doses higher than 30 Gy. One disadvantage of the FXG system is its poor storage stability, because the non-irradiated samples suffer a selfdegradation and this could be a limitation for the use of FXG system. (author)

  7. Feasibility study of a lead(II) iodide-based dosimeter for quality assurance in therapeutic radiology

    Science.gov (United States)

    Heo, Y. J.; Kim, K. T.; Oh, K. M.; Lee, Y. K.; Ahn, K. J.; Cho, H. L.; Kim, J. Y.; Min, B. I.; Mun, C. W.; Park, S. K.

    2017-09-01

    The most widely used form of radiotherapy to treat tumors uses a linear accelerator, and the apparatus requires regular quality assurance (QA). QA for a linear accelerator demands accuracy throughout, from mock treatment and treatment planning, up to treatment itself. Therefore, verifying a radiation dose is essential to ensure that the radiation is being applied as planned. In current clinical practice, ionization chambers and diodes are used for QA. However, using conventional gaseous ionization chambers presents drawbacks such as complex analytical procedures, difficult measurement procedures, and slow response time. In this study, we discuss the potential of a lead(II) iodide (PbI2)-based radiation dosimeter for radiotherapy QA. PbI2 is a semiconductor material suited to measurements of X-rays and gamma rays, because of its excellent response properties to radiation signals. Our results show that the PbI2-based dosimeter offers outstanding linearity and reproducibility, as well as dose-independent characteristics. In addition, percentage depth dose (PDD) measurements indicate that the error at a fixed reference depth Dmax was 0.3%, very similar to the measurement results obtained using ionization chambers. Based on these results, we confirm that the PbI2-based dosimeter has all the properties required for radiotherapy: stable dose detection, dose linearity, and rapid response time. Based on the evidence of this experimental verification, we believe that the PbI2-based dosimeter could be used commercially in various fields for precise measurements of radiation doses in the human body and for measuring the dose required for stereotactic radiosurgery or localized radiosurgery.

  8. 1987 Neutron and gamma personnel dosimeter intercomparison study using a D/sub 2/O-moderated /sup 252/Cf source

    Energy Technology Data Exchange (ETDEWEB)

    Swaja, R.E.; West, L.E.; Sims, C.S.; Welty, T.J.

    1989-05-01

    The thirteenth Personnel Dosimetry Intercomparison Study (i.e., PDIS 13) was conducted during April 1987 as a joint effort by Oak Ridge National Laboratory's (ORNL) Dosimetry Applications Research Group and the Southwest Radiation Calibration Center at the University of Arkansas. A total of 48 organizations (34 from the US and 14 from abroad) participated in PDIS 13. Participants submitted a total of 1,113 neutron and gamma dosimeters for this mixed field study. The dosimeters were transferred by mail and were handled by experimental personnel at ORNL and the University of Arkansas. The type of neutron dosimeter and the percentage of participants submitting that type are as follows: TLD-albedo (49%), direct interaction TLD (31%), CR-39 (17%), film (3%). The type of gamma dosimeter and the percentage of participants submitting that type are as follows: Li/sub 2/B/sub 4/O/sub 7/, alone or in combination with CaSO/sub 4/, (69%), /sup 7/LiF (28%), natural LiF (3%). Radiation exposures in PDIS 13 were limited to 0.5 and 1.5 mSv from /sup 252/Cf moderated by 15-cm of D/sub 2/O. Traditional exposures using the Health Physics Research Reactor (HPRR) were not possible due to the fact that all reactors at ORNL, including the HPRR, were shutdown by order of the Department of Energy at the time the intercomparison was performed. Planned exposures using a /sup 238/PuBe source were negated by a faulty timing mechanism. Based on accuracy and precision, direct interaction TLD dosimeters exhibited the best performance in PDIS 13 neutron measurements. They were followed, in order of best performance, by CR-39, TLD albedo, and film. The Li/sub 2/B/sub 4/O/sub 7/ type TLD dosimeters exhibited the best performance in PDIS 13 gamma measurements. They were followed by natural LiF, /sup 7/LiF, and film. 12 refs., 1 fig., 5 tabs.

  9. Sand of Colombian beaches as low cost thermoluminescent dosimeter for radiotherapy title

    Energy Technology Data Exchange (ETDEWEB)

    Cogollo P, R.; Ricaurte A, D.; Alvarino B, G., E-mail: rrcogollo@sinu.unicordoba.edu.co [University of Cordoba, Materials and Applied Physics Group, Carrera 6 No. 76-103, Monteria, Cordoba (Colombia)

    2013-10-01

    This paper describes the thermoluminescent characteristics of the sand coming from Colombian beaches (Covenas and Monitos), for its use as dosimeter in therapeutic dose. The selected samples, annealed at 400 C per 1 hour, were irradiated under different doses using a unity of {sup 60}Co Theratron 780 C on air at room temperature. The reading was carried out in a Harshaw TLD 4500. The main dosimetric properties of the material (glow curve, response reproducibility, reuse, linearity and thermal decay) have been in detail studied. The results show a lineal response to the dose from 50 c Gy to 1000 c Gy, in the material. The studied samples of sand can be used as thermoluminescent dosimeters for applications in different fields. The importance of this work is that the sand is a natural low cost substance, available in large quantities, and can be used in clinical physics in order to make assessments about the received dose by the patient during the medical treatment. (Author)

  10. Theory for source-responsive and free-surface film modeling of unsaturated flow

    Science.gov (United States)

    Nimmo, J.R.

    2010-01-01

    A new model explicitly incorporates the possibility of rapid response, across significant distance, to substantial water input. It is useful for unsaturated flow processes that are not inherently diffusive, or that do not progress through a series of equilibrium states. The term source-responsive is used to mean that flow responds sensitively to changing conditions at the source of water input (e.g., rainfall, irrigation, or ponded infiltration). The domain of preferential flow can be conceptualized as laminar flow in free-surface films along the walls of pores. These films may be considered to have uniform thickness, as suggested by field evidence that preferential flow moves at an approximately uniform rate when generated by a continuous and ample water supply. An effective facial area per unit volume quantitatively characterizes the medium with respect to source-responsive flow. A flow-intensity factor dependent on conditions within the medium represents the amount of source-responsive flow at a given time and position. Laminar flow theory provides relations for the velocity and thickness of flowing source-responsive films. Combination with the Darcy-Buckingham law and the continuity equation leads to expressions for both fluxes and dynamic water contents. Where preferential flow is sometimes or always significant, the interactive combination of source-responsive and diffuse flow has the potential to improve prediction of unsaturated-zone fluxes in response to hydraulic inputs and the evolving distribution of soil moisture. Examples for which this approach is efficient and physically plausible include (i) rainstorm-generated rapid fluctuations of a deep water table and (ii) space- and time-dependent soil water content response to infiltration in a macroporous soil. ?? Soil Science Society of America.

  11. Pyroelectric and piezoelectric responses of thin AlN films epitaxy-grown on a SiC/Si substrate

    Science.gov (United States)

    Kukushkin, S. A.; Osipov, A. V.; Sergeeva, O. N.; Kiselev, D. A.; Bogomolov, A. A.; Solnyshkin, A. V.; Kaptelov, E. Yu.; Senkevich, S. V.; Pronin, I. P.

    2016-05-01

    This paper presents the results of pyroelectric and piezoelectric studies of AlN films formed by chloride-hydride epitaxy (CHE) and molecular beam epitaxy (MBE) on epitaxial SiC nanolayers grown on Si by the atom substitution method. The surface topography and piezoelectric and pyroelecrtric responses of AlN films have been analyzed. The results of the study have shown that the vertical component of the piezoresponse in CHE-grown AlN films is more homogeneous over the film area than that in MBE-grown AlN films. However, the signal from the MBE-synthesized AlN films proved to be stronger. The inversion of the polar axis (polarization vector) on passage from MBE-grown AlN films to CHE-grown AlN films has been found experimentally. It has been shown that the polar axis in MBE-grown films is directed from the free surface of the film toward the Si substrate while, in CHE-grown films, the polarization vector is directed toward the free surface.

  12. New routes of preparation of polyaniline films and dosimetric characterization for high-doses gamma radiation; Novas rotas de preparacao de filmes de polianilina e caracterizacao dosimetrica para radiacao gama em altas doses

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco, Ana Paula Lima

    2003-08-15

    This work presents a new conducting polymeric material based on polyaniline thin films that will be used in the confection of dosimetric devices. On preparation of the films a homogeneous and viscous solution of poly (acrylic acid) and MnO{sub 2} is deposited on PMMA surface, which after dried, is immersed in an acid aniline solution. The films formed present low resistivity (6.10{sup 2} {omega}m), good mechanical resistance and adherence on the electrodes. The films were characterized by infrared spectroscopy, conductivity measurements and manganese elemental analyses. The resistance variations show linear correlation (r{sup 2} = 0,9928) with gamma irradiation dose in the range of 1000 to 6000 Gy, with medium error less than 5% and sensitivity response. The dosimetric devices present as advantage real time measurements, low cost, use in calibration of industrial radioactive sources. Moreover, this composite could in future replace Fricke dosimeter and its applications. A calibration curve is showed for PANI dosimeter, here proposed, to use at high gamma doses. (author)

  13. Measuring solar UV radiation with EBT radiochromic film.

    Science.gov (United States)

    Butson, Ethan T; Cheung, Tsang; Yu, Peter K N; Butson, Martin J

    2010-10-21

    Ultraviolet radiation dosimetry has been performed with the use of a radiochromic film dosimeter called Gafchromic EBT for solar radiation exposure. The film changes from a clear colour to blue colour when exposed to ultraviolet radiation and results have shown that the colour change is reproducible within ±10% at 5 kJ m(-2) UV exposure under various conditions of solar radiation. Parameters tested included changes in season (summer versus winter exposure), time of day, as well as sky conditions such as cloudy skies versus clear skies. As the radiochromic films' permanent colour change occurs in the visible wavelengths the film can be analysed with a desktop scanner with the most sensitive channel for analysis being the red component of the signal. Results showed that an exposure of 5 kJ m(-2) (approximately 1 h exposure in full sun during summer) produced an approximate 0.28 change in the net OD when analysed in reflection mode on the desktop scanner which is significant darkening. The main advantages of this film type, and thus the new EBT2 film which has replaced EBT for measurement of UV exposure, is the visible colour change and thus easy analysis using a desktop scanner, its uniformity in response and its robust physical strength for use in outside exposure situations.

  14. Gender differences in sexual arousal and affective responses to erotica: the effects of type of film and fantasy instructions.

    Science.gov (United States)

    Carvalho, Joana; Gomes, Ana Quinta; Laja, Pedro; Oliveira, Cátia; Vilarinho, Sandra; Janssen, Erick; Nobre, Pedro

    2013-08-01

    The present study examined men and women's sexual and affective responses to erotic film clips that were combined with different fantasy instructions. Men (n = 29) and women (n = 28) were presented with two types of erotic films (explicit vs. romantic) and two fantasy instructions (fantasizing about one's real-life partner vs. fantasizing about someone else). Genital response, subjective sexual arousal, and affective responses were assessed. Sexually explicit stimuli resulted in larger genital responses; women reported higher subjective sexual arousal than men; and fantasizing about one's partner resulted, overall, in higher subjective sexual arousal and higher levels of positive affect. Moreover, in women, the instruction to fantasize about one's partner resulted in stronger subjective sexual arousal to the explicit film than the instruction to fantasize about someone else. Results suggested that physiological, subjective, and affective responses to erotic film stimuli are impacted not only by stimulus characteristics but also by the viewer's interpretation of the depicted relationship.

  15. Dosimetric response of radiochromic films to protons of low energies in the Bragg peak region

    Science.gov (United States)

    Battaglia, M. C.; Schardt, D.; Espino, J. M.; Gallardo, M. I.; Cortés-Giraldo, M. A.; Quesada, J. M.; Lallena, A. M.; Miras, H.; Guirado, D.

    2016-06-01

    One of the major advantages of proton or ion beams, applied in cancer treatment, is their excellent depth-dose profile exhibiting a low dose in the entrance channel and a distinct dose maximum (Bragg peak) near the end of range in tissue. In the region of the Bragg peak, where the protons or ions are almost stopped, experimental studies with low-energy particle beams and thin biological samples may contribute valuable information on the biological effectiveness in the stopping region. Such experiments, however, require beam optimization and special dosimetry techniques for determining the absolute dose and dose homogeneity for very thin biological samples. At the National Centre of Accelerators in Seville, one of the beam lines at the 3 MV Tandem Accelerator was equipped with a scattering device, a special parallel-plate ionization chamber with very thin electrode foils and target holders for cell cultures. In this work, we present the calibration in absolute dose of EBT3 films [Gafchromic radiotherapy films, http://www.ashland.com/products/gafchromic-radiotherapy-films] for proton energies in the region of the Bragg peak, where the linear energy transfer increases and becomes more significant for radiobiology studies, as well as the response of the EBT3 films for different proton energy values. To irradiate the films in the Bragg peak region, the energy of the beam was degraded passively, by interposing Mylar foils of variable thickness to place the Bragg peak inside the active layer of the film. The results obtained for the beam degraded in Mylar foils are compared with the dose calculated by means of the measurement of the beam fluence with an ionization chamber and the energy loss predicted by srim2008 code.

  16. Thermoluminescence on ZrO{sub 2} films with different dopants; Termoluminiscencia en peliculas de ZrO{sub 2} con distintos impurificantes

    Energy Technology Data Exchange (ETDEWEB)

    Ceron R, P. V.; Rivera M, T.; Ramos G, A. I.; Guzman M, J.; Montes R, E., E-mail: victceronr@hotmail.com [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria No. 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico)

    2015-10-15

    Full text: The metal oxides doped with rare earths have presented good thermoluminescent properties for certain wavelengths in the UV. With respect to zirconium oxide exist several studies in which were incorporated impurities and their properties as dosimeter in several regions of the electromagnetic spectrum were analyzed. Because of this background, in this material thermoluminescent glow curves induced by UV in films of ZrO{sub 2}:Eu and ZrO{sub 2}:Tb were studied for comparison with the response of the material doped with two rare earths (ZrO{sub 2}:Eu + Tb). Samples were deposited on glass by ultrasonic spray pyrolysis technique with different synthesis parameters. It was found that the strongest Tl response was to ZrO{sub 2} film doped with terbium (14 times more intense than the film of ZrO{sub 2}:Eu and 6 times the response of ZrO{sub 2}:Eu + Tb). (Author)

  17. pH-responsiveness of multilayered films and membranes made of polysaccharides

    Science.gov (United States)

    Silva, Joana M.; Caridade, Sofia G.; Costa, Rui R.; Alves, Natália M.; Groth, Thomas; Picart, Catherine; Reis, Rui L.; Mano, João F.

    2016-01-01

    We investigated the pH-dependent properties of multilayered films made of chitosan (CHI) and alginate (ALG) and focused on their post-assembly response to different pH environments using quartz crystal microbalance with dissipation monitoring (QCM-D), swelling studies, zeta potential measurements and dynamic mechanical analysis (DMA). In an acidic environment, the multilayers presented lower dissipation values and, consequently, higher moduli when compared with the values obtained for the pH used during the assembly (5.5). When the multilayers were exposed to alkaline environments the opposite behavior occurred. These results were further corroborated with the ability of this multilayered system to exhibit a reversible swelling-deswelling behavior within the pH range from 3 to 9. The changes of the physicochemical properties of the multilayer system were gradual and different from the ones of individual solubilized polyelectrolytes. This behavior is related to electrostatic interactions between the ionizable groups combined with hydrogen-bonding and hydrophobic interactions. Beyond the pH range of 3-9 the multilayers were stabilized by genipin cross-linking. The multilayered films also became more rigid while preserving the pH-responsiveness conferred by the ionizable moieties of the polyelectrolytes. This work demonstrates the versatility and feasibility of LbL methodology to generate inherently pH stimuli-responsive nanostructured films. Surface functionalization using pH-repsonsiveness endows abilities for several biomedical applications such as drug delivery, diagnostics, microfluidics, biosensing or biomimetic implantable membranes. PMID:26421873

  18. Characterization of hydrogen responsive nanoporous palladium films synthesized via a spontaneous galvanic displacement reaction

    Science.gov (United States)

    Patton, J. F.; Lavrik, N. V.; Joy, D. C.; Hunter, S. R.; Datskos, P. G.; Smith, D. B.; Sepaniak, M. J.

    2012-11-01

    A model is presented regarding the mechanistic properties associated with the interaction of hydrogen with nanoporous palladium (np-Pd) films prepared using a spontaneous galvanic displacement reaction (SGDR), which involves PdCl2 reduction by atomic Ag. Characterization of these films shows both chemical and morphological factors, which influence the performance characteristics of np-Pd microcantilever (MC) nanomechanical sensing devices. Raman spectroscopy, uniquely complemented with MC response profiles, is used to explore the chemical influence of palladium oxide (PdO). These combined techniques support a reaction mechanism that provides for rapid response to H2 and recovery in the presence of O2. Post-SGDR processing via reduction of PdCl2(s) in a H2 environment results in a segregated nanoparticle three-dimensional matrix dispersed in a silver layer. The porous nature of the reduced material is shown by high resolution scanning electron microscopy. Extended grain boundaries, typical of these materials, result in a greater surface area conducive to fast sorption/desorption of hydrogen, encouraged by the presence of PdO. X-ray diffraction and inductively coupled plasma-optical emission spectroscopy are employed to study changes in morphology and chemistry occurring in these nanoporous films under different processing conditions. The unique nature of chemical/morphological effects, as demonstrated by the above characterization methods, provides evidence in support of observed nanomechanical response/recovery profiles offering insight for catalysis, H2 storage and improved sensing applications.

  19. CdWO{sub 4}-on-MEH-PPV:PS as a candidate for real-time dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M.M. [Laboratory of Polymers and Electronic Properties of Materials, UFOP, 35400-000 (Brazil); Novais, S.M.V.; Silva, E.S.S. [Group of Advanced Ceramic Materials, UFS, 49100-000 (Brazil); Schimitberger, T. [Laboratory of Polymers and Electronic Properties of Materials, UFOP, 35400-000 (Brazil); Macedo, Z.S. [Group of Advanced Ceramic Materials, UFS, 49100-000 (Brazil); Bianchi, R.F., E-mail: bianchi@iceb.ufop.br [Laboratory of Polymers and Electronic Properties of Materials, UFOP, 35400-000 (Brazil)

    2012-10-15

    We report on the investigations about the modification of optical properties induced by X-rays onto film detectors of cadmium tungstate (CdWO{sub 4}), poly[2-methoxy-5(2 Prime -ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) and polystyrene (PS) This device takes advantage of reduction of spectral overlap between the radioluminescence (RL) of CdWO{sub 4} and the absorption of MEH-PPV as it is exposed to radiation, forming the basis of a new dosimeter that is capable of converting the orange-red radioluminescence of PS:MEH-PPV:CdWO{sub 4} into green. We propose an explanation of the optical processes occurring in MEH-PPV:CdWO{sub 4} in terms of the radiation hardness of CdWO{sub 4} combined to the RL-induced degradation of MEH-PPV. Highlights: Black-Right-Pointing-Pointer Thin composite film dosimeters using a combination of a scintillator crystal and a light-emitting polymer. Black-Right-Pointing-Pointer A X-ray dose detector based on MEH-PPV/CdWO{sub 4} materials which are rarely seen together. Black-Right-Pointing-Pointer A new smart, disposable and easy-to-read organic-inorganic radiation detector.

  20. Cardiovascular, electrodermal, and respiratory response patterns to fear- and sadness-inducing films.

    Science.gov (United States)

    Kreibig, Sylvia D; Wilhelm, Frank H; Roth, Walton T; Gross, James J

    2007-09-01

    Responses to fear- and sadness-inducing films were assessed using a broad range of cardiovascular (heart rate, T-wave amplitude, low- and high-frequency heart rate variability, stroke volume, preejection period, left-ventricular ejection time, Heather index, blood pressure, pulse amplitude and transit time, and finger temperature), electrodermal (level, response rate, and response amplitude), and respiratory (rate, tidal volume and its variability, inspiratory flow rate, duty cycle, and end-tidal pCO(2)) measures. Subjective emotional experience and facial behavior (Corrugator Supercilii and Zygomaticus Major EMG) served as control measures. Results indicated robust differential physiological response patterns for fear, sadness, and neutral (mean classification accuracy 85%). Findings are discussed in terms of the fight-flight and conservation-withdrawal responses and possible limitations of a valence-arousal categorization of emotion in affective space.

  1. Performances of Dose Measurement of Commercial Electronic Dosimeters using Geiger Muller Tube and PIN Diode

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Hyunjun; Kim, Chankyu; Kim, Yewon; Kim, Giyoon; Cho, Gyuseong [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    There are two categories in personal dosimeters, one is passive type dosimeter such as TLD (thermoluminescence dosimeter) and the other is active type dosimeter such as electronic dosimeter can show radiation dose immediately while TLD needs long time to readout its data by heating process. For improving the reliability of measuring dose for any energy of radiations, electronic dosimeter uses energy filter by metal packaging its detector using aluminum or copper, but measured dose of electronic dosimeter with energy filter cannot be completely compensated in wide radiation energy region. So, in this paper, we confirmed the accuracy of dose measurement of two types of commercial EPDs using Geiger Muller tube and PIN diode with CsI(Tl) scintillator in three different energy of radiation field. The experiment results for Cs-137 was almost similar with calculation value in the results of both electronic dosimeters, but, the other experiment values with Na-22 and Co-60 had higher error comparing with Cs-137. These results were caused by optimization of their energy filters. The optimization was depending on its thickness of energy filter. So, the electronic dosimeters have to optimizing the energy filter for increasing the accuracy of dose measurement or the electronic dosimeter using PIN diode with CsI(Tl) scintillator uses the multi-channel discriminator for using its energy information.

  2. EPR and UV spectroscopic study of table sugar as a high-dose dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Yordanov, N.D. E-mail: ndyepr@bas.bg; Gancheva, V.; Georgieva, E

    2002-10-01

    The possibilities for the estimation of the absorbed dose for high-energy radiation with a new self-calibrated dosimeter containing table sugar as a radiation-sensitive material and Mn{sup 2+}/MgO as an internal standard by the method of electron paramagnetic resonance (EPR) is reported. The dose response of this dosimeter is represented as the ratio between the EPR signal intensities of sugar and Mn{sup 2+} versus absorbed dose. Because the EPR spectra of both substances are simultaneously recorded, the influence of some related instrumental setting parameters were investigated. UV spectral studies on water solutions of irradiated solid sugar were also performed. In all solutions of irradiated sugar samples a band at 267 nm was recorded as linearly increasing intensity with the absorbed dose. The minimum detectable dose using the UV spectrum of water solutions of irradiated sugar is 100 Gy. Combination of EPR and UV spectral data is possible to use for independent internal or international calibration and control of dose estimations.

  3. The use of commercial glass as a potential gamma accidental dosimeter through the absorption spectra

    Energy Technology Data Exchange (ETDEWEB)

    Kharita, M.H., E-mail: prscientific1@aec.org.sy [Atomic Energy Commission, Damascus, P.O. Box 6091 (Syrian Arab Republic); Yousef, S.; Bakr, S. [Atomic Energy Commission, Damascus, P.O. Box 6091 (Syrian Arab Republic)

    2012-05-01

    Various types of commercial glass (ordinary windows, cathode ray tubes, glass kitchenware) have been studied as potential accidental radiation dosimeters. The proposed method utilizes the changes in the glasses' absorption spectra as a result of irradiation. A {sup 60}Co gamma irradiation cell has been used to irradiate samples with doses ranging from 5 to 200 Gy. The transmittance was measured using a photospectrometer (UV-visible spectrometry). The results demonstrate that the transmittance spectra of most of the glass samples change in linear proportion to the exposure dose. Moreover, the study considers the fading effect on the absorption spectra of the irradiated samples for fading times up to 100 days at room temperature. The results of this work demonstrate that several widely used types of glass can be used as high-dose accidental dosimeters for doses ranging between 8 and 200 Gy. A reasonable calibration line can be established for any irradiated glass sample by heating, re-irradiating with standard doses and measuring the related absorption coefficient. Further investigations are needed to decrease the minimum detectable dose of the proposed method and to study the effect of glass composition on radiation response.

  4. Sub-nanometer expansions of redox responsive polymer films monitored by imaging ellipsometry.

    Science.gov (United States)

    Cumurcu, Aysegul; Feng, Xueling; Ramos, Lionel Dos; Hempenius, Mark A; Schön, Peter; Vancso, G Julius

    2014-10-21

    We describe a novel approach to quantitatively visualize sub nm height changes occurring in thin films of redox active polymers upon reversible electrochemical oxidation/reduction in situ and in real-time with electrochemical imaging ellipsometry (EC-IE). Our approach is based on the utilization of a micro-patterned substrate containing circular patterns of passive (non-redox active) 11-mercapto-1-undecanol (MCU) within a redox-responsive oligoethylene sulfide end-functionalized poly(ferrocenyldimethylsilane) (ES-PFS) film on a gold substrate. The non-redox responsive MCU layer was used as a molecular reference layer for the direct visualization of the minute thickness variations of the ES-PFS film. The ellipsometric microscopy images were recorded in aqueous electrolyte solutions at potentials of -0.1 V and 0.6 V vs. Ag/AgCl corresponding to the reduced and oxidized redox states of ES-PFS, respectively. The ellipsometric contrast images showed a 37 (±2)% intensity increase in the ES-PFS layer upon oxidation. The thickness of the ES-PFS layer reversibly changed between 4.0 (±0.1) nm and 3.4 (±0.1) nm upon oxidation and reduction, respectively, as determined by IE. Additionally, electrochemical atomic force microscopy (EC-AFM) was used to verify the redox controlled thickness variations. The proposed method opens novel avenues to optically visualize minute and rapid height changes occurring e.g. in redox active (and other stimulus responsive) polymer films in a fast and non-invasive manner.

  5. Negligible substrate clamping effect on piezoelectric response in (111)-epitaxial tetragonal Pb(Zr, Ti)O{sub 3} films

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Tomoaki, E-mail: t-yamada@nucl.nagoya-u.ac.jp [Department of Materials, Physics and Energy Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Yasumoto, Jun; Ito, Daisuke; Yoshino, Masahito; Nagasaki, Takanori [Department of Materials, Physics and Energy Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Sakata, Osami [Synchrotron X-ray Station at SPring-8 and Synchrotron X-ray Group, National Institute for Materials Science, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Department of Innovative and Engineered Material, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Imai, Yasuhiko [Japan Synchrotron Radiation Research Institute, SPring-8, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Kiguchi, Takanori [Institute for Materials Research, Tohoku University, Sendai, Miyagi 980-8577 (Japan); Shiraishi, Takahisa; Shimizu, Takao; Funakubo, Hiroshi [Department of Innovative and Engineered Material, Tokyo Institute of Technology, Yokohama 226-8503 (Japan)

    2015-08-21

    The converse piezoelectric responses of (111)- and (001)-epitaxial tetragonal Pb(Zr{sub 0.35}Ti{sub 0.65})O{sub 3} [PZT] films were compared to investigate the orientation dependence of the substrate clamping effect. Synchrotron X-ray diffraction (XRD) and piezoelectric force microscopy revealed that the as-grown (111)-PZT film has a polydomain structure with normal twin boundaries that are changed by the poling process to inclined boundaries, as predicted by Romanov et al. [Phys. Status Solidi A 172, 225 (1999)]. Time-resolved synchrotron XRD under bias voltage showed the negligible impact of substrate clamping on the piezoelectric response in the (111)-PZT film, unlike the case for (001)-PZT film. The origin of the negligible clamping effect in the (111)-PZT film is discussed from the viewpoint of the elastic properties and the compensation of lattice distortion between neighboring domains.

  6. Small field in-air output factors: The role of miniphantom design and dosimeter type

    Energy Technology Data Exchange (ETDEWEB)

    Warrener, Kirbie, E-mail: kirbie.warrener@sesiahs.health.nsw.gov.au [Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, New South Wales 2521, Australia and Centre for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales 2522 (Australia); Hug, Benjamin; Ebert, Martin A. [School of Physics, University of Western Australia, Crawley, Western Australia 6009, Australia and Department of Radiation Oncology, Sir Charles Gairdner Hospital, Perth, Western Australia 6009 (Australia); Liu, Paul; McKenzie, David R. [School of Physics, University of Sydney, Darlington, New South Wales 2008 (Australia); Ralston, Anna [Chris O' Brien Lifehouse, Radiation Oncology, Sydney, New South Wales 2050 (Australia); Suchowerska, Natalka [School of Physics, University of Sydney, Darlington, New South Wales 2008, Australia and Chris O' Brien Lifehouse, Radiation Oncology, Sydney, New South Wales 2050 (Australia)

    2014-02-15

    Purpose: The commissioning of treatment planning systems and beam modeling requires measured input parameters. The measurement of relative output in-air, S{sub c} is particularly difficult for small fields. The purpose of this study was to investigate the influence of miniphantom design and detector selection on measured S{sub c} values for small fields and to validate the measurements against Monte Carlo simulations. Methods: Measurements were performed using brass caps (with sidewalls) or tops (no sidewalls) of varying heights and widths. The performance of two unshielded diodes (60012 and SFD), EBT2 radiochromic film, and a fiber optic dosimeter (FOD) were compared for fields defined by MLCs (5–100 mm) and SRS cones (4–30 mm) on a Varian Novalis linear accelerator. Monte Carlo simulations were performed to theoretically predict S{sub c} as measured by the FOD. Results: For all detectors, S{sub c} agreed to within 1% for fields larger than 10 mm and to within 2.3% for smaller fields. Monte Carlo simulation matched the FOD measurements for all size of cone defined fields to within 0.5%. Conclusions: Miniphantom design is the most important variable for reproducible and accurate measurements of the in-air output ratio, S{sub c}, in small photon fields (less than 30 mm). Sidewalls are not required for fields ≤ 30 mm and tops are therefore preferred over the larger caps. Unlike output measurements in water, S{sub cp,} the selection of detector type for S{sub c} is not critical, provided the active dosimeter volume is small relative to the field size.

  7. Hard X-ray dose intensity and spatial distribution in a plasma focus device using thermoluminescence dosimeters

    Indian Academy of Sciences (India)

    A Kanani; M N Nasrabadi; B Shirani; I Jabbari

    2015-07-01

    In the present study, X-ray emission dose characteristics from a small Mather-type PF device in various pressures of argon as the operating gas were studied. The PF device was powered by a 12 F capacitor at 25 kV charging voltage. Time-integrated hard X-ray (HXR) emission was investigated using thermoluminescence dosimeters (TLDs). These detectors were calibrated with 60Co and 131Cs sources. Twenty-four dosimeters were placed at four different radial distances from the axis of the electrodes at the top of the anode to measure the dose spatial distribution at the top of the anode for different pressures (0.5–1.3 mbar). At each radius, six dosimeters were placed circularly with equal angular intervals on the inner surface of the device chamber. It was found that the optimum pressure for the highest yield of X-ray is 0.9 mbar. The maximum measured dose was 17 mGy per shot at the top of the anode and about 0.5 mGy per shot at 90° with respect to the anode axis. Furthermore, these results showed that the dose at each radius is symmetrical at 360° around the top of the anode, but X-ray distribution follows an anisotropical behaviour. A fast plastic scintillator was also used for time-resolved HXR detection, and a linear relation was observed between the amplitude of the scintillator-PMT signals and TLD responses.

  8. Correcting the Response of an Albedo Neutron Dosimeter for Energy

    Science.gov (United States)

    2007-01-01

    Radiat. Prot. Dosim. V19 #2. Gauch, H.G. Jr., 1993. “Prediction Parsimony and Noise,” American Scientist 81 468-478. Glickstein, S.S., 1981...Analysis,” American Scientist 80 64-72. Johnson, J.O., J.D. Drischler, J.M. Barnes, 1991. Analysis of the Fall-1989 Two-Meter Box Test- Bed

  9. Thermal stimulated current response in cupric oxide single crystal thin films over a wide temperature range

    Science.gov (United States)

    Yang, Kungan; Wu, Shuxiang; Yu, Fengmei; Zhou, Wenqi; Wang, Yunjia; Meng, Meng; Wang, Gaili; Zhang, Yueli; Li, Shuwei

    2017-01-01

    Cupric oxide single crystal thin films (~26 nm) were grown by plasma-assisted molecular beam epitaxy. X-ray diffraction, Raman spectra and in situ reflection high-energy electron diffraction show that the thin films are 2  ×  2 reconstructed with an in-plane compression and out-of-plane stretching. A thermal stimulated current measurement indicates that the electric polarization response is shown in the special 2D cupric oxide single crystal thin film over a wide temperature range from 130 K to near-room temperature. We infer that the abnormal electric response involves the changing of phase transition temperature induced by structure distortion, the spin frustration and the magnetic fluctuation effect of a short-range magnetic order, or the combined action of both of the two factors mentioned above. This work suggests a promising clue for finding new room temperature single phase multiferroics or tuning phase transition temperatures.

  10. Study of L-aspartic acid for its possible use as a dosimeter in the interval of 3.4-20 kGy at different irradiation temperatures

    Science.gov (United States)

    Meléndez-López, Adriana; Negrón-Mendoza, Alicia; Gómez-Vidales, Virginia; Uribe, Roberto M.; Ramos-Bernal, Sergio

    2014-11-01

    Certain commercial applications of radiation processing increase the efficiency of chemical reactions at low temperatures to decrease the free radicals in the bulk material and avoid the synergistic effects of heat. Such applications have motivated the search for a reliable, low-temperature dosimeter for use under the conditions of the irradiation process. For this purpose, polycrystalline samples of L-aspartic acid (2-aminobutanedioic acid) were irradiated with gamma rays at low temperatures and doses in the kiloGray range (3.4-64 kGy). The potential use of the aspartic acid system as a chemical dosimeter is based on the formation of stable free radicals when the amino acid is exposed to ionizing radiation. These radicals can be studied and quantified using electron spin resonance (ESR). The response curves at different temperatures show that the intensity of the ESR spectra (the five characteristic lines) depends on the dose received. The response of the dosimeter increases with increasing temperature, and this relationship is linear up to 20 kGy at 298 K. The decay characteristics show that the change in the ESR signal over time is low and reproducible. In addition, the L-aspartic acid dosimeter is easy to handle and has low cost.

  11. Pyroelectric response of lead zirconate titanate thin films on silicon: Effect of thermal stresses

    Energy Technology Data Exchange (ETDEWEB)

    Kesim, M. T.; Zhang, J.; Alpay, S. P. [Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Trolier-McKinstry, S. [Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, Pennsylvania 16802 (United States); Mantese, J. V. [United Technologies Research Center, East Hartford, Connecticut 06118 (United States); Whatmore, R. W. [Tyndall National Institute, Lee Maltings, Dyke Parade, Cork City, County Cork (Ireland)

    2013-11-28

    Ferroelectric lead zirconate titanate [Pb(Zr{sub x}Ti{sub 1-x}O){sub 3}, (PZT x:1-x)] has received considerable interest for applications related to uncooled infrared devices due to its large pyroelectric figures of merit near room temperature, and the fact that such devices are inherently ac coupled, allowing for simplified image post processing. For ferroelectric films made by industry-standard deposition techniques, stresses develop in the PZT layer upon cooling from the processing/growth temperature due to thermal mismatch between the film and the substrate. In this study, we use a non-linear thermodynamic model to investigate the pyroelectric properties of polycrystalline PZT thin films for five different compositions (PZT 40:60, PZT 30:70, PZT 20:80, PZT 10:90, PZT 0:100) on silicon as a function of processing temperature (25–800 °C). It is shown that the in-plane thermal stresses in PZT thin films alter the out-of-plane polarization and the ferroelectric phase transformation temperature, with profound effect on the pyroelectric properties. PZT 30:70 is found to have the largest pyroelectric coefficient (0.042 μC cm{sup −2} °C{sup −1}, comparable to bulk values) at a growth temperature of 550 °C; typical to what is currently used for many deposition processes. Our results indicate that it is possible to optimize the pyroelectric response of PZT thin films by adjusting the Ti composition and the processing temperature, thereby, enabling the tailoring of material properties for optimization relative to a specific deposition process.

  12. A new 2 methylalanine-PVC ESR dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, Bruno T. [Departmento de Fisica e Matematica, FFCLRP-Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto-SP (Brazil); Chen, Felipe [Departmento de Fisica e Matematica, FFCLRP-Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto-SP (Brazil); Department of Radiological Health, Caja de Seguro Social, Panama City (Panama); Department of Physics, Faculty of Natural and Exact Sciences and Technology, University of Panama, Panama City (Panama); Baffa, Oswaldo [Departmento de Fisica e Matematica, FFCLRP-Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto-SP (Brazil)

    2005-02-01

    The use of polyvinyl chloride (PVC) as a binder to 2-methylalanine (2MA) dosimeters was investigated. It was recently shown by Olsson et al. (Radiat. Res. 157 (2002) 113), that 2MA is approximately 70% more sensitive than L-alanine which makes this substance a good candidate to replace alanine in ESR dosimetry. PVC is a low yield material for free radical production by ionizing radiation and a good binding material easily processed and widely available. PVC can be prepared at room temperature and mixed up to 50% in weight with 2MA to produce a pellet stable in mass and physical dimensions, in large quantities and with low background signal. Pure PVC pellet irradiated at 50 Gy gave weaker ESR signals compared to 2MA at the region of spectral interest. Spectrometer settings such as microwave power, and modulation amplitude were optimized for the measurements. This dosimeter production scheme allows the addition of Mn{sup 2+} ions for an internal reference signal, leading to a self-calibrated dosimeter (J. Radional. Nucl. Chem. 240 (1999) 215)

  13. Nano-barium–strontium sulfate as a new thermoluminescence dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Aboelezz, E., E-mail: eslam_genius@hotmail.com [Department of Ionizing Radiation, National Institute for Standards, El-Giza (Egypt); Sharaf, M.A.; Hassan, G.M. [Department of Ionizing Radiation, National Institute for Standards, El-Giza (Egypt); El-Khodary, A. [Department of Physics, Faculty of Science, Mansoura University (Egypt)

    2015-10-15

    A sensitive thermoluminescence (Ba{sub 0.88}Sr{sub 0.12}SO{sub 4}){sub 99.8%}:Eu{sub 0.2%} (B88) nano-phosphor has been prepared using the chemical co-precipitation method. A comparative study of B88 nanophosphor with its corresponding prepared micro-crystalline form has been made. The dose response of nano-B88, to γ-ray in low and intermediate ranges, was studied in comparison with micro-phase and reference material (TL-700H). The supralinearity factors for nano/micro-B88 and TL-700H are calculated and compared between them along both low and intermediate dose ranges. The lower detection limit of dose calculation (D{sub LDL}) method is compared with the detection limit (D{sub DL}) and critical level (D{sub CL}) of dose calculation algorithm. According to B88 energy dependence study, it is energy dependent for all photon energies except from 0.8 to 4 MeV due to their high value of effective atomic number (Z{sub eff}=43.5). Nano-B88 is sensitive to light, so the nano-B88 should be stored in dark region away from any source of visible and UV-light. The fading and reusability studies of both nano/micro-B88 samples are also included. The combined and expanded uncertainties that accompanied the radiation dose measurements are calculated. - Highlights: • A comparative study of nano/micro-B88 form has been made. • The sensitivity of both phases for B88 in low range of dose is ≈50 times TL-700H. • The lower detection limit of dose calculation was found to be ≈135 μGy for nano-B88. • B88 is energy independent for photon energies ranging from 0.8 to 4 MeV. • Nano-B88 can be used as a good TL dosimeter in radiation dosimetry.

  14. SU-E-T-130: Dosimetric Evaluation of Tissue Equivalent Gel Dosimeter Using Saccharide in Radiotherapy System

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Y [Korea Institute of Radiological and Medical Sciences (KIRAMS), Seoul (Korea, Republic of); Lee, D; Jung, H; Ji, Y; Kim, K; Chang, U [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Kwon, S [Kyonggi University, Suwon-si, Gyeonggi-do (Korea, Republic of)

    2014-06-01

    Purpose: In this study, the dose responses of the MAGIC gel with various concentrations and type of saccharide are examined to clarify the roles of mono and disaccharide in the polymerization process. Then we focused on the tissue equivalence and dose sensitivity of MAGIC gel dosimeters. Methods: The gel is composed of HPLC, 8% gelatin, 2 × 10-3 M L-ascorbic acid, 1.8 × 10-2 M hydroquinone, 8 × 10-5 M copper(II)sulfate and 9% methacrylic acid, new polymer gels are synthesized by adding glucose(monosaccharide), sucrose(disaccharide) and urea in the concentration range of 5∼35%. For irradiation of the gel, cesium-137 gamma-ray irradiator was used, radiation dose was delivered from 5∼50 Gy. MRI images of the gel were acquired by using a 3.0 T MRI system. Results: When saccharide and urea were added, the O/C, O/N and C/N ratios agreed with those of soft tissue with 1.7%. The dose-response of glucose and sucrose gel have slope-to-intercept ratio of 0.044 and 0.283 respectively. The slope-to-ratio is one important determinant of gel sensitivity. R-square values of glucose and sucrose gel dosimeters were 0.984 and 0.994 respectively. Moreover when urea were added, the slope-to-intercept ratio is 0.044 and 0.073 respectively. R-square values of mono and disaccharide gel were 0.973 and 0.989 respectively. When a saccharide is added into the MAGIC gel dosimeter, dose sensitivity is increased. However when urea were added, dose sensitivity is slightly decreased. Conclusion: In this study, it was possible to obtain the following conclusions by looking at the dose response characteristics after adding mono-, di-saccharide and urea to a MAGIC gel dosimeter. Saccharide was a tendency of increasing dose sensitivity with disaccharide. Sa.ccharide is cost effective, safe, soft tissue equivalent, and can be used under various experimental conditions, making it a suitable dosimeter for some radiotherapy applications.

  15. A Stimuli-Responsive Biosensor of Glucose on Layer-by-Layer Films Assembled through Specific Lectin-Glycoenzyme Recognition

    Directory of Open Access Journals (Sweden)

    Huiqin Yao

    2016-04-01

    Full Text Available The research on intelligent bioelectrocatalysis based on stimuli-responsive materials or interfaces is of great significance for biosensors and other bioelectronic devices. In the present work, lectin protein concanavalin A (Con A and glycoenzyme glucose oxidase (GOD were assembled into {Con A/GOD}n layer-by-layer (LbL films by taking advantage of the biospecific lectin-glycoenzyme affinity between them. These film electrodes possess stimuli-responsive properties toward electroactive probes such as ferrocenedicarboxylic acid (Fc(COOH2 by modulating the surrounding pH. The CV peak currents of Fc(COOH2 were quite large at pH 4.0 but significantly suppressed at pH 8.0, demonstrating reversible stimuli-responsive on-off behavior. The mechanism of stimuli-responsive property of the films was explored by comparative experiments and attributed to the different electrostatic interaction between the films and the probes at different pH. This stimuli-responsive films could be used to realize active/inactive electrocatalytic oxidation of glucose by GOD in the films and mediated by Fc(COOH2 in solution, which may establish a foundation for fabricating novel stimuli-responsive electrochemical biosensors based on bioelectrocatalysis with immobilized enzymes.

  16. Thin-Film Magnetic-Field-Response Fluid-Level Sensor for Non-Viscous Fluids

    Science.gov (United States)

    Woodard, Stanley E.; Shams, Qamar A.; Fox, Robert L.; Taylor, Bryant D.

    2008-01-01

    An innovative method has been developed for acquiring fluid-level measurements. This method eliminates the need for the fluid-level sensor to have a physical connection to a power source or to data acquisition equipment. The complete system consists of a lightweight, thin-film magnetic-field-response fluid-level sensor (see Figure 1) and a magnetic field response recorder that was described in Magnetic-Field-Response Measurement-Acquisition System (LAR-16908-1), NASA Tech Briefs, Vol. 30, No. 6 (June 2006), page 28. The sensor circuit is a capacitor connected to an inductor. The response recorder powers the sensor using a series of oscillating magnetic fields. Once electrically active, the sensor responds with its own harmonic magnetic field. The sensor will oscillate at its resonant electrical frequency, which is dependent upon the capacitance and inductance values of the circuit.

  17. Standard Guide for Performance Characterization of Dosimeters and Dosimetry Systems for Use in Radiation Processing

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This guide provides guidance on determining the performance characteristics of dosimeters and dosimetry systems used in radiation processing. 1.2 This guide describes the influence quantities that might affect the performance of dosimeters and dosimetry systems and that should be considered during dosimeter/dosimetry system characterization. 1.3 Users of this guide are directed to existing standards and literature for procedures to determine the effects from individual influence quantities and from combinations of more than one influence quantity. 1.4 Guidance is provided regarding the roles of the manufacturers, suppliers, and users in the characterization of dosimeters and dosimetry systems. 1.5 This guide does not address how the dosimeter/dosimetry system characterization information is to be used in radiation processing applications or in the calibration of dosimetry systems. Note 1—For guidance on the use of dosimeter/dosimetry system characterization information for the selection and use o...

  18. Effect of metal coordination on photocurrent response properties of a tetrathiafulvalene organogel film.

    Science.gov (United States)

    Ji, Shu-Fang; Sun, Yong-Gang; Huo, Peng; Shen, Wei-Chun; Huang, Yu-De; Zhu, Qin-Yu; Dai, Jie

    2014-04-07

    Organic low molecular weight gelators with a tetrathiafulvalene (TTF) unit have received considerable attention because the formed gels usually exhibit redox active response and conducting or semiconducting properties. However, to our knowledge, metal coordination systems have not been reported for TTF-derived gels up to date. We have designed and synthesized a series of TTF derivatives with a diamide-diamino moiety that can coordinate to specific metal ions with square coordination geometry. Gelation properties and morphologies of the films prepared by the gelators in different hydrophobic solvents are characterized. The TTF derivative with a dodecyl group shows effective gelation properties, and electrodes with the organogel films are prepared. The effect of the Ni(II) and Cu(II) coordination on the photocurrent response property of the electrodes is examined. The metal square coordination significantly increases the photocurrent response. This gel system is the first metal coordination related TTF-gel-based photoelectric material. The mechanism of the metal coordination-improved photocurrent response property is discussed based on the crystal structural analysis and theoretical calculations.

  19. Laboratory Evaluation of a Colorimetric Hydrazine Dosimeter

    Science.gov (United States)

    1990-06-12

    Dose Response Curve at T=O for PDAB (D12) without Diffusion Membrane o 0.1 ppm x 0.2 ppm v 0.4 ppm - 1-6 ppm 10 0 - 9 o x a 0 8 0 7 x 6 0 O 5 -V...x x 4 0- 1X 3r V x 2 0- x 00 0 2 4 6 8 10 12 14 16 18 20 Dose (TLV-hrs) Fig. 6b. MMH Dose Response Curve at T=I for PDAB (D12) without Diffusion...TLV-hrs) Fig. 6c. MMH Dose Response Curve at T=0 for PDAB (D12) with Diffusion Membrane 11 o 0.1 ppm x 0.2 ppm v 0.4 ppm * 1-6 ppm 10 9 B 8 0 a; xx7

  20. Fabrication and Optimization of a PAGATA Gel Dosimeter: Increasing the Melting Point of the PAGAT Gel Dosimeter with Agarose Additive

    Directory of Open Access Journals (Sweden)

    Bakhtiar Azadbakht

    2010-12-01

    Full Text Available Introduction: The PAGAT polymer gel dosimeter melts at 30 ˚C and even at room temperature during the summer, so it needs to be kept in a cool place such as a refrigerator. To increase the stability of the PAGAT gel, different amounts of agarose were added to the PAGAT gel composition and the PAGATA gel was manufactured. Material and Methods: The PAGATA gel vials were irradiated using a Co-60 machine. Then, the samples were evaluated using a 1.5 T Siemens MRI scanner. The ingredients of the PAGATA normoxic gel dosimeter were 4.5% N-N' methylen-bis-acrylamide, 4.5% acrylamide, 4.5% gelatine, 5 mM tetrakis (THPC, 0.01 mM hydroquinone (HQ, 0.5% agarose and 86% de-ionized water (HPLC. Results: Melting point and sensitivity of the PAGAT gel dosimeter with addition of 0.0, 0.3, 0.5, 1.0, 1.5 and 2.0% of agarose were measured, in which the melting points were increased to 30, 82, 86, 88, 89 and 90°C and their sensitivities found to be 0.113, 0.1059, 0.125, 0.122, 0.115 and 0.2  respectively. Discussion and Conclusions: Adding agarose increased the sensitivity and background R2 of the evaluated samples. The optimum amount of agarose was found to be 0.5% regarding these parameters and also the melting point of the gel dosimeter. A value of 0.5% agarose was found to be an optimum value considering the increase of sensitivity to 0.125 and melting point to 86°C but at the expense of increasing the background R2 to 4.530.

  1. Research of Methodocal Questions of Use of Albedo Personal Neutron Dosi-meter

    CERN Document Server

    Alekseev, A G

    2003-01-01

    In the paper the methods of reception of the correct use of neutron albedo dosimeters are considered. The methods of use such dosimeters in fields with different spectra of neutrons are presented. For testing the experi-mental research of sensitivity DVGN-01and DVN-A-01 dosimeters in reference neutron fields was formed on based of 1-st horizontal research channel of IRT MIPHI reactor.

  2. Ionizing radiation M.O.S. dosimeters: sensibility and stability; Dosimetres M.O.S. de rayonnements ionisants: sensibilite et stabilite

    Energy Technology Data Exchange (ETDEWEB)

    Gessinn, F.

    1993-12-01

    This thesis is a contribution to the study of the ionizing radiation responsivity of P.O.M.S. dosimeters. Unlike the development of processing hardening techniques, our works goal were to increase, on the one hand, the M.O.S. dosimeters sensitivity in order to detect small radiation doses and on the other hand, the stability with time and temperature of the devices, to minimize the absorbed-dose estimation errors. With this aim in mind, an analysis of all processing parameters has been carried out: the M.O.S. dosimeter sensitivity is primarily controlled by the gate oxide thickness and the irradiation electric field. Thus, P.M.O.S. transistors with 1 and 2 {mu}m thick silica layers have been fabricated for our experiments. The radiation response of our devices in the high-field mode satisfactorily fits a D{sub ox}{sup 2} power law. The maximum sensitivity achieved (9,2 V/Gy for 2{mu}m devices) is close to the ideal value obtained when considering only an unitary carrier-trapping level, and allows to measure about 10{sup -2} Gy radiation doses. Read-time stability has been evaluated under bias-temperature stress conditions: experiments underscore slow fading, corresponding to 10{sup -3} Gy/h. The temperature response has also been studied: the analytical model we have developed predicts M.O.S. transistors threshold voltage variations over the military specifications range [-50 deg. C, + 150 deg. C]. Finally, we have investigated the possibilities of irradiated dosimeters thermal annealing for reusing. It appears clearly that radiation-induced damage annealing is strongly gate bias dependent. Furthermore, dosimeters radiation sensitivity seems not to be affected by successive annealings. (author). 146 refs., 58 figs., 9 tabs.

  3. Investigation of radiological properties and water equivalency of PRESAGE dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Gorjiara, Tina; Hill, Robin; Kuncic, Zdenka; Adamovics, John; Bosi, Stephen; Kim, Jung-Ha; Baldock, Clive [Institute of Medical Physics, School of Physics, University of Sydney, New South Wales 2006 (Australia); Institute of Medical Physics, School of Physics, University of Sydney, New South Wales 2006 (Australia) and Department of Radiation Oncology, Royal Prince Alfred Hospital, Sydney, New South Wales 2050 (Australia); Institute of Medical Physics, School of Physics, University of Sydney, New South Wales 2006 (Australia); Department of Chemistry and Biology, Rider University, Lawrenceville, New Jersey 08648 (United States); Institute of Medical Physics, School of Physics, University of Sydney, New South Wales 2006 (Australia) and Department of Radiation Oncology, Prince of Wales Hospital, Randwick, New South Wales 2031 (Australia); Institute of Medical Physics, School of Physics, University of Sydney, New South Wales 2006 (Australia)

    2011-04-15

    Purpose: PRESAGE is a dosimeter made of polyurethane, which is suitable for 3D dosimetry in modern radiation treatment techniques. Since an ideal dosimeter is radiologically water equivalent, the authors investigated water equivalency and the radiological properties of three different PRESAGE formulations that differ primarily in their elemental compositions. Two of the formulations are new and have lower halogen content than the original formulation. Methods: The radiological water equivalence was assessed by comparing the densities, interaction probabilities, and radiation dosimetry properties of the three different PRESAGE formulations to the corresponding values for water. The relative depth doses were calculated using Monte Carlo methods for 50, 100, 200, and 350 kVp and 6 MV x-ray beams. Results: The mass densities of the three PRESAGE formulations varied from 5.3% higher than that of water to as much as 10% higher than that of water for the original formulation. The probability of photoelectric absorption in the three different PRESAGE formulations varied from 2.2 times greater than that of water for the new formulations to 3.5 times greater than that of water for the original formulation. The mass attenuation coefficient for the three formulations is 12%-50% higher than the value for water. These differences occur over an energy range (10-100 keV) in which the photoelectric effect is the dominant interaction. The collision mass stopping powers of the relatively lower halogen-containing PRESAGE formulations also exhibit marginally better water equivalency than the original higher halogen-containing PRESAGE formulation. Furthermore, the depth dose curves for the lower halogen-containing PRESAGE formulations are slightly closer to that of water for a 6 MV beam. In the kilovoltage energy range, the depth dose curves for the lower halogen-containing PRESAGE formulations are in better agreement with water than the original PRESAGE formulation. Conclusions: Based

  4. Enhanced UV-sensitivity of vis-responsive anatase thin films fabricated by using precursor solutions involving Ti complexes

    Energy Technology Data Exchange (ETDEWEB)

    Nagai, Hiroki; Mochizuki, Chihiro; Hara, Hiroki; Sato, Mitsunobu [Coordination Engineering Laboratory, Faculty of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji City, Tokyo 192-0015 (Japan); Takano, Ichiro [Department of Electrical Engineering, Kogakuin University, 2665-1 Nakano, Hachioji City, Tokyo 192-0015 (Japan)

    2008-09-15

    Fabrication of vis-responsive anatase thin films with enhanced UV-sensitivity was attained on an ITO pre-coated glass substrate by applying two precursor solutions involving Ti complexes of oxalic acid and EDTA. The transparent and crack-free thin films were characterized by XRD, XPS, UV-vis and FE-SEM observation. The highest sensitivity to UV light of the vis-responsive film, whose photocatalytic activity was measured by the decomposition rate of methylene blue, was four times as compared with that formed by a sol-gel method under the same conditions. The vis-responsive films showed a characteristic absorption band at around 480 nm. (author)

  5. Bifurcations in the response of a flexible rotor in squeeze-film dampers with retainer springs

    Energy Technology Data Exchange (ETDEWEB)

    Inayat-Hussain, Jawaid I. [School of Engineering, Monash University Malaysia, No. 2, Jalan Kolej, Bandar Sunway, 46150 Petaling Jaya, Selangor Darul Ehsan (Malaysia)], E-mail: jawaid.inayat-hussain@eng.monash.edu.my

    2009-01-30

    Squeeze-film dampers are commonly used in conjunction with rolling-element or hydrodynamic bearings in rotating machinery. Although these dampers serve to provide additional damping to the rotor-bearing system, there have however been some cases of rotors mounted in these dampers exhibiting non-linear behaviour. In this paper a numerical study is undertaken to determine the effects of design parameters, i.e., gravity parameter, W, mass ratio, {alpha}, and stiffness ratio, K, on the bifurcations in the response of a flexible rotor mounted in squeeze-film dampers with retainer springs. The numerical simulations were undertaken for a range of speed parameter, {omega}, between 0.1 and 5.0. Numerical results showed that increasing K causes the onset speed of bifurcation to increase, whilst an increase of {alpha} reduces the onset speed of bifurcation. For a specific combination of K and {alpha} values, the onset speed of bifurcation appeared to be independent of W. The instability of the rotor response at this onset speed was due to a saddle-node bifurcation for all the parameter values investigated in this work with the exception of the combination of {alpha} = 0.1 and K = 0.5, where a secondary Hopf bifurcation was observed. The speed range of non-synchronous response was seen to decrease with the increase of {alpha}; in fact non-synchronous rotor response was totally absent for {alpha}=0.4. With the exception of the case {alpha} = 0.1, the speed range of non-synchronous response was also seen to decrease with the increase of K. Multiple responses of the rotor were observed at certain values of {omega} for various combinations of parameters W, {alpha} and K, where, depending on the values of the initial conditions the rotor response could be either synchronous or quasi-periodic. The numerical results presented in this work were obtained for an unbalance parameter, U, value of 0.1, which is considered as the upper end of the normal unbalance range of most practical

  6. Bifurcations of a flexible rotor response in squeeze-film dampers without centering springs

    Energy Technology Data Exchange (ETDEWEB)

    Inayat-Hussain, Jawaid I. [School of Engineering, Monash University Malaysia, No. 2, Jalan Kolej, Bandar Sunway, Petaling Jaya 46150, Selangor Darul Ehsan (Malaysia)]. E-mail: jawaid.inayat-hussain@eng.monash.edu.my

    2005-04-01

    Squeeze-film dampers are often utilized in high-speed rotating machinery to provide additional external damping to the rotor-bearing system for the purpose of reducing the synchronous response of the rotor especially while traversing critical speeds, or to eliminate rotor instability problems. The application of these dampers are widely found in aircraft gas turbine engines that are usually mounted on rolling element bearings, which are known to provide almost negligible damping to the system. Although the squeeze-film damper is an inherently stable machine element, its operation at certain parameters may give rise to undesirable non-synchronous vibration. The effects of the design and operating parameters, namely the bearing parameter, B, gravity parameter, W, and mass ratio, {alpha}, on the bifurcations in the response of a flexible rotor supported by squeeze-film dampers without centering springs were examined using direct numerical integration. Specifically, the effects of these parameters on the onset speed of bifurcation and the extent of non-synchronous response of the rotor within the range of speed parameter, {omega}, between 0.5 and 5.0 were determined. Numerical simulation results showed the occurrence of period-2, period-4 and quasi-periodic vibrations in the response of the rotor as the speed parameter, {omega}, was varied from 0.5 to 5. The results further showed that increasing B resulted in the increase of the onset speed of bifurcation, and a decrease in the range of {omega} where non-synchronous response was observed. With the exception of the case of W = 0.0, the increase of W was found to increase the onset speed of bifurcation and also the range of {omega} where non-synchronous response was observed. The effect of increasing {alpha} resulted in a decrease in the range of {omega} where non-synchronous response existed. The increase of {alpha} also caused the onset speed of bifurcation to increase, except for the case of B = 0.05, W = 0.0, where

  7. Response of Ag Thick Film Microstripline due to Superstrate Strontium Substituted Bismuth Manganites

    Directory of Open Access Journals (Sweden)

    S.N. Mathad

    2014-06-01

    Full Text Available The purpose of this paper is to describe the use of strontium-substituted bismuth manganites bulk ceramic superstrate on Ag thick film microstripline, to modify its response and measure complex permittivity as a function of strontium. Bismuth strontium manganites (Bi1 − xSrxMnO3 have been synthesized by solid state sintering technique. The perturbation obtained in the transmittance and reflectance of thick film microstripline due to the Bi1 − xSrxMnO3 (0.20  x  0.50 overlay has been used to obtain the permittivity at microwave frequencies in X and Ku band range. Due to the overlay of Bismuth strontium manganites (BSM pellets a substantial increase in the effective dielectric constant was observed in X band more compared to Ku band. The in-touch overlay method provides ease loading and unloading. The perturbation obtained in the transmittance and reflectance of thick film microstripline due to the bismuth strontium manganites overlay has been used to obtain the permittivity.

  8. Dopamine and norepinephrine responses to film-induced sexual arousal in sexually functional and sexually dysfunctional women.

    Science.gov (United States)

    Meston, C M; McCall, K M

    2005-01-01

    This study was designed to assess potential differences between sexually functional and dysfunctional women in dopamine (DA) and norepinephrine (NE) responses to erotic stimuli. Blood levels of homovanillic acid (HVA; the major metabolite of DA) and NE were taken during the showing of a nonsexual and a sexual film from 9 women with female sexual arousal disorder and hypoactive sexual desire disorder and from 13 sexually functional women. We assessed sexual arousal subjectively using a self-report scale and physiologically using a vaginal photoplethysmograph. HVA levels significantly decreased in sexually functional and dysfunctional women during the erotic versus during the neutral film. NE levels were not significantly different for either group of women during the neutral and erotic films. Sexually dysfunctional women had significantly higher levels of NE during both the neutral and erotic films compared with functional women. Subjective or physiological arousal differences between neutral and erotic films were not significantly different between functional and dysfunctional women.

  9. AC Response to Humidity and Propane of Sprayed Fe-Zn Oxide Films

    Directory of Open Access Journals (Sweden)

    Alejandro AVILA-GARCÍA

    2009-09-01

    Full Text Available Iron-zinc oxide films with different Zn contents were ultrasonically sprayed on glass substrates and inter-digital gold electrodes were evaporated upon them. Films were deposited from solutions containing 2, 10 and 30 at. % Zn. Hematite, amorphous and Franklinite structures turned out, respectively. They were assessed as humidity and propane detectors under alternating-current conditions for frequencies from 1 to 105 Hz and temperatures 30 and 250 oC. Their impedances in dry air, humid air and humid air plus propane were determined from voltage measurements with a Lock-In amplifier. Sensitivities to humidity (53 % RH. and 189, 500 and 786 ppm of propane from the response of the resistance, reactance and also the total impedance were determined as functions of frequency. The maximum sensitivity to humidity ranges from 24 % up to 308 %. For propane, the maximum sensitivity ranges from 45 % up to 711 %. The largest sensitivity values correspond in all cases to reactance. From the dynamical response, the response and recovery times are determined, along with the concentration-dependence of the sensitivity. The sensing mechanisms are commented.

  10. Irreversible thermochromic response of RF sputtered nanocrystalline BaWO{sub 4} films for smart window applications

    Energy Technology Data Exchange (ETDEWEB)

    Anil Kumar, C.; Santhosh Kumar, T.; Pamu, D., E-mail: pamu@iitg.ernet.in [Department of Physics, Indian Institute of Technology Guwahati, Guwahati -781039 (India)

    2015-10-15

    quantify the presence of oxygen vacancies and the formation of pure BWO phase. The obtained optical responses of BWO films are promising for solar cell and smart window applications.

  11. Frustrated magnetic response of a superconducting Nb film with a square lattice of columnar defects

    Energy Technology Data Exchange (ETDEWEB)

    Zadorosny, R; Ortiz, W A [Grupo de Supercondutividade e Magnetismo, Departamento de Fisica, Universidade Federal de Sao Carlos, Sao Carlos, SP (Brazil); Lepienski, C M [Universidade Federal do Parana, Departamento de Fisica, Curitiba, PR (Brazil); Patino, E; Blamire, M G [Department of Materials Science, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom)], E-mail: rafazad@df.ufscar.br

    2008-02-01

    The magnetic response of a superconducting system presenting a frustrated state is investigated. The system is a superconducting film with mechanically pierced columns, cooled in a field which is then removed. Frustration originates from the competition between return flux of a dipole - created by flux trapped in the empty columns - and flux exclusion by the surrounding superconductor in the Meissner state. The system resolves the incompatibility among conflicting constraints, leading to frustration, by eliminating return flux, which is possibly assimilated by nearby columns, as manifested by a sudden reduction of the magnetic moment on the decreasing field branch of the hysteresis loop.

  12. Synthesis of environmentally responsive organic materials by application of ion track holes in polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Omichi, Hideki; Yoshida, Masaru; Asano, Masaharu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Katakai, Ryoichi; Spohr, R.; Vetter, J.

    1997-03-01

    Polymer films were irradiated by heavy ion beams and etched by a concentrated alkali solution to produce particle track membranes (PTMs). Then the PTMs were chemically modified by grafting such monomers as amino acid group containing methacryloyl and N-isopropylacrylamide the polymers of which are known as environmentally responsive hydrogels. The size of pores of the modified PTMs under different temperatures in water was followed by electron microscopy. The pore was controlled from an open state to a completely closed state by changing temperature. The conductivity through the membrane was measured by changing the temperature of the cell. (author)

  13. Solid-state dosimeters: A new approach for mammography measurements

    Energy Technology Data Exchange (ETDEWEB)

    Brateman, Libby F., E-mail: bratel@radiology.ufl.edu [Department of Radiology, University of Florida College of Medicine Box 100374, Gainesville, Florida 32610-0374 (United States); Heintz, Philip H. [Department of Radiology, University of New Mexico, MSC10 5530, Albuquerque, New Mexico 87131 (United States)

    2015-02-15

    Purpose: To compare responses of modern commercially available solid-state dosimeters (SStDs) used in mammography medical physics surveys for two major vendors of current digital mammography units. To compare differences in dose estimates among SStD responses with ionization chamber (IC) measurements for several target/filter (TF) combinations and report their characteristics. To review scientific bases for measurements of quantities required for mammography for traditional measurement procedures and SStDs. Methods: SStDs designed for use with modern digital mammography units were acquired for evaluation from four manufacturers. Each instrument was evaluated under similar conditions with the available mammography beams provided by two modern full-field digital mammography units in clinical use: a GE Healthcare Senographe Essential (Essential) and a Hologic Selenia Dimensions 5000 (Dimensions), with TFs of Mo/Mo, Mo/Rh; and Rh/Rh and W/Rh, W/Ag, and W/Al, respectively. Measurements were compared among the instruments for the TFs over their respective clinical ranges of peak tube potentials for kVp and half-value layer (HVL) measurements. Comparisons for air kerma (AK) and their associated relative calculated average glandular doses (AGDs), i.e., using fixed mAs, were evaluated over the limited range of 28–30 kVp. Measurements were compared with reference IC measurements for AK, reference HVLs and calculated AGD, for two compression paddle heights for AK, to evaluate scatter effects from compression paddles. SStDs may require different positioning from current mammography measurement protocols. Results: Measurements of kVp were accurate in general for the SStDs (within −1.2 and +1.1 kVp) for all instruments over a wide range of set kVp’s and TFs and most accurate for Mo/Mo and W/Rh. Discrepancies between measurements and reference values were greater for HVL and AK. Measured HVL values differed from reference values by −6.5% to +3.5% depending on the SStD and

  14. Effect of bath concentration on the growth and photovoltaic response of SILAR-deposited CuO thin films

    Science.gov (United States)

    Visalakshi, S.; Kannan, R.; Valanarasu, S.; Kim, Hyun-Seok; Kathalingam, A.; Chandramohan, R.

    2015-09-01

    Solar cell property of p-CuO/n-Si heterojunction was investigated using SILAR-deposited CuO thin films. The effects of copper salt concentration on the growth of CuO films and its effect on the efficiency in solar cell conversion were investigated. Structural, morphological, optical and electrical studies of the CuO thin films deposited at 90 °C with different copper sulphate concentrations are reported. Crystallinity of the film is found to increase with the increase in copper sulphate concentration. The measured Raman spectrum of the deposited film showed peaks corresponding to CuO phase. It is observed by the SEM that the film is homogeneous fully covering the substrate. The optical band gap of the deposited film has exhibited a decrease in band gap from 1.76 to 1.57 eV with the increase in copper sulphate concentration. Solar cell device was constructed using the p-CuO film deposited on n-silicon substrate, and its photovoltaic response was measured. It showed increasing photoresponse with increasing concentration of copper sulphate.

  15. Hemicyanine LB film—Silver nanoparticle composite: contrasting fluorescence responses sensitive to the ultrathin film assembly sequence

    Science.gov (United States)

    Maganti, Lasya; Dwivedi, Itisha; Jose, Anju; Radhakrishnan, T. P.

    2017-07-01

    Fluorescence emission of molecules is strongly influenced by the plasmonic field of metal nanoparticles, with significant enhancement induced under optimal conditions. Nanocomposite ultrathin films fabricated with citrate-stabilized Ag nanoparticles and LB film of a cationic hemicyanine amphiphile, are shown to produce opposing fluorescence emission trends upon subtle variation in the assembly sequence. Monolayer LB films of the pure amphiphile show aggregation-induced quenching with increasing deposition pressure. Composite films formed by adsorption of Ag nanoparticles on the Langmuir film (self-assembly together with steered assembly) followed by LB transfer, show further quenching. However, adsorption of Ag nanoparticles on the pre-formed amphiphile LB film (self-assembly following steered assembly), causes the fluorescence to increase with the extent of adsorption. Spectroscopy and microscopy provide insight into the contrasting, tunable emission. Formation of Ag nanoparticle chains on the Langmuir film and their direct contact with the monolayer cause the fluorescence quenching; adsorption of isolated Ag nanoparticles on the LB film along with multilayer formation leads to the enhancement. The study illustrates the versatility of LB film—metal nanoparticle composites in producing distinct materials responses through subtle changes in the mode of assembly.

  16. High-dose dosimetry of beta rays using blue beryl dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Carmo, Lucas S. do, E-mail: lsatiro@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Watanabe, Shigueo; Bittencour, Jose F., E-mail: Lacifid@if.usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica. Departamento de Fisica Nuclear

    2015-07-01

    High dose radiation is widely used in industrial applications as sterilization of medical products, improvement of materials properties, color enhancement of jewelry stones, etc. The radiation dosimetry of high doses is quite important for these applications. In this work we have investigated the usage of blue beryl crystal also known as aquamarine in high dose dosimetry of beta rays. Some works have shown that silicate minerals exhibit a good Thermoluminescent response when irradiated up to 2000 kGy of gamma rays. Here, we have produced small beryl pellets of approximately 5 mm in diameter and 3 mm thickness to measure high doses of beta rays produced at an electron accelerator at IPEN. Twelve beryl dosimeters were made and six of them were irradiated from 10kGy up to 100 kGy. The technique used to create a calibration curve was the thermoluminescence using the glow peak at 310°C. (author)

  17. Solid state dosimeters used in medical physics 'A review'

    Energy Technology Data Exchange (ETDEWEB)

    Azorin-Nieto, Juan [Physics Department, Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186 Col. Vicentina, 09340 Mexico, D.F. (Mexico)

    2012-10-23

    Many solid-state detectors have been successfully used to perform the quality control and in vivo dosimetry in medical physics, both in diagnostic radiology and radiotherapy, as they have high sensitivity in a small volume; most of them do not require electrical connection and have dosimetric characteristics of interest such as: good accuracy and reproducibility, as well as a response independent of the energy of radiation, some of them. For this reason, the selection of an appropriate detector for use in medical physics must take into account the energy mass absorption coefficient relative to water for photon sources and the mass stopping power relative to water for beta emitters and electron beams in the energy range of interest in medical physics, as well as the effective atomic number of materials that constitute them. This paper presents a review of the dosimetric characteristics of the solid state dosimeters most suitable for use in medical physics.

  18. Evaluation of thermoluminescent dosimeters using water equivalent phantoms for application in clinical electrons beams dosimetry; Avaliacao de dosimetros termoluminescentes empregando objetos simuladores equivalentes a agua para aplicacao na dosimetria de feixes clinicos de eletrons

    Energy Technology Data Exchange (ETDEWEB)

    Bravim, Amanda

    2010-07-01

    The dosimetry in Radiotherapy provides the calibration of the radiation beam as well as the quality control of the dose in the clinical routine. Its main objective is to determine with greater accuracy the dose absorbed by the tumor. This study aimed to evaluate the behavior of three thermoluminescent dosimeters for the clinical electron beam dosimetry. The performance of the calcium sulfate detector doped with dysprosium (CaSO{sub 4}: Dy) produced by IPEN was compared with two dosimeters commercially available by Harshaw. Both are named TLD-100, however they differ in their dimensions. The dosimeters were evaluated using water, solid water (RMI-457) and PMMA phantoms in different exposure fields for 4, 6, 9, 12 and 16 MeV electron beam energies. It was also performed measurements in photon beams of 6 and 15 MV (2 and 5 MeV) only for comparison. The dose-response curves were obtained for the {sup 60}Co gamma radiation in air and under conditions of electronic equilibrium, both for clinical beam of photons and electrons in maximum dose depths. The sensitivity, reproducibility, intrinsic efficiency and energy dependence response of dosimeters were studied. The CaSO{sub 4}: Dy showed the same behavior of TLD-100, demonstrating only an advantage in the sensitivity to the beams and radiation doses studied. Thus, the dosimeter produced by IPEN can be considered a new alternative for dosimetry in Radiotherapy departments. (author)

  19. Scintillating fiber optic dosimeters for breast and prostate brachytherapy

    Science.gov (United States)

    Moutinho, L. M.; Castro, I. F.; Freitas, H.; Melo, J.; Silva, P.; Gonçalves, A.; Peralta, L.; Rachinhas, P. J.; Simões, P. C. P. S.; Pinto, S.; Pereira, A.; Santos, J. A. M.; Costa, M.; Veloso, J. F. C. A.

    2017-02-01

    Brachytherapy is a radiotherapy modality where the radioactive material is placed close to the tumor, being a common treatment for skin, breast, gynecological and prostate cancers. These treatments can be of low-dose-rate, using isotopes with mean energy of 30 keV, or high-dose-rate, using isotopes such as 192Ir with a mean energy of 380 keV. Currently these treatments are performed in most cases without in-vivo dosimetry for quality control and quality assurance. We developed a dosimeter using small diameter probes that can be inserted into the patient's body using standard brachytherapy needles. By performing real-time dosimetry in breast and prostate brachytherapy it will be possible to perform real-time dose correction when deviations from the treatment plan are observed. The dosimeter presented in this work was evaluated in-vitro. The studies consisted in the characterization of the dosimeter with 500 μm diameter sensitive probes (with a BCF-12 scintillating optical fiber) using an inhouse made gelatin breast phantom with a volume of 566 cm3. A breast brachytherapy treatment was simulated considering a tumor volume of 27 cm3 and a prescribed absolute dose of 5 Gy. The dose distribution was determined by the Inverse Planning Simulated Annealing (IPSA) optimization algorithm (ELEKTA). The dwell times estimated from the experimental measurements are in agreement with the prescribed dwell times, with relative error below 3%. The measured signal-to-noise ratio (SNR) including the stem-effect contribution is below 3%.

  20. Gafchromic EBT3 film dosimetry in electron beams - energy dependence and improved film read-out.

    Science.gov (United States)

    Sipilä, Petri; Ojala, Jarkko; Kaijaluoto, Sampsa; Jokelainen, Ilkka; Kosunen, Antti

    2016-01-01

    For megavoltage photon radiation, the fundamental dosimetry characteristics of Gafchromic EBT3 film were determined in 60Co gamma ray beam with addition of experimental and Monte Carlo (MC)-simulated energy dependence of the film for 6 MV photon beam and 6 MeV, 9 MeV, 12 MeV, and 16 MeV electron beams in water phantom. For the film read-out, two phase correction of scanner sensitivity was applied: a matrix correction for scanning area and dose-dependent correction by iterative procedure. With these corrections, the uniformity of response can be improved to be within ± 50 pixel values (PVs). To improve the read-out accuracy, a procedure with flipped film orientations was established. With the method, scanner uniformity can be improved further and dust particles, scratches and/or dirt on scan-ner glass can be detected and eliminated. Responses from red and green channels were averaged for read-out, which decreased the effect of noise present in values from separate channels. Since the signal level with the blue channel is considerably lower than with other channels, the signal variation due to different perturbation effects increases the noise level so that the blue channel is not recommended to be used for dose determination. However, the blue channel can be used for the detection of emulsion thickness variations for film quality evaluations with unexposed films. With electron beams ranging from 6 MeV to 16 MeV and at reference measurement conditions in water, the energy dependence of the EBT3 film is uniform within 0.5%, with uncertainties close to 1.6% (k = 2). Including 6 MV photon beam and the electron beams mentioned, the energy dependence is within 1.1%. No notable differences were found between the experimental and MC-simulated responses, indicating negligible change in intrinsic energy dependence of the EBT3 film for 6 MV photon beam and 6 MeV-16 MeV electron beams. Based on the dosimetric characteristics of the EBT3 film, the read-out procedure established

  1. Atmospheric effects on the photosensitive response of poly(methylphenylsilane) thin films.

    Energy Technology Data Exchange (ETDEWEB)

    Potter, Barrett George, Jr. (University of Arizona, Tucson, AZ); Chandra, Haripin (University of Arizona, Tucson, AZ); Simmons-Potter, Kelly (University of Arizona, Tucson, AZ); Thomes, William Joseph, Jr.; Jamison, Gregory Marks

    2004-06-01

    Agile ready-when-needed patterning of refractive index structures in photosensitive materials requires an understanding of the impact of local application environment on mechanisms contributing to the desired photoinduced index change. The present work examines the impact of atmosphere on the photosensitive response of poly(methylphenylsilane) (PMPS) thin films whose high photoinduced index change under low incident optical fluence make them attractive candidates for such applications. Changes in optical absorption and refractive index are investigated after exposure to ultraviolet (UV) light resonant with the lowest energy transition exhibited by the Si-Si backbone structure in the material. A comparison between photoinduced absorption changes for thin films exposed in an air atmosphere versus those observed for samples subjected to a nitrogen environment during photoexposure is made for the first time. The study reveals that the anaerobic conditions of the nitrogen atmosphere significantly reduce the photosensitive response of the material to light. These results are discussed in terms of photooxidation processes within the polysilane structure and in the context of the need for predictable photosensitive refractive index change in varied photoimprinting environments.

  2. Preliminary study of diffusion effects in Fricke gel dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Quiroga, A. [Centro de Investigacion y Estudios de Matematica de Cordoba, Oficina 318 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina); Vedelago, J. [Laboratorio de Investigaciones e Instrumentacion en Fisica Aplicada a la Medicina e Imagenes por Rayos X, Laboratorio 448 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina); Valente, M., E-mail: aiquiroga@famaf.unc.edu [Instituto de Fisica Enrique Gaviola, Oficina 102 FaMAF - UNC, Av. Luis Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2014-08-15

    Diffusion of ferric ions in ferrous sulfate (Fricke) gels represents one of the main drawbacks of some radiation detectors, like Fricke gel dosimeters. In practice, this disadvantage can be overcome by prompt dosimeter analysis, constraining strongly the time between irradiation and analysis. Due to required integral accuracy levels, special dedicated protocols are implemented with the aim of minimizing signal blurring due to diffusion effects. This work presents dedicated analytic modelling and numerical calculations of diffusion coefficients in Fricke gel radiation sensitive material. Samples are optically analysed by means of visible light transmission measurements capturing images with a Ccd camera provided with a monochromatic 585 nm filter corresponding to the X O-infused Fricke solution absorbance peak. Dose distributions in Fricke gels are suitably delivered in order to assess specific initial conditions further studied by periodical sample image acquisitions. In a first analytic approach, experimental data are fit with linear models in order to achieve a value for the diffusion coefficient. The second approach to the problem consists on a group of computational algorithms based on inverse problem formulation, along with suitable 2D diffusion model capable of estimating diffusion coefficients by fitting the obtained algorithm numerical solutions with the corresponding experimental data. Comparisons are performed by introducing an appropriate functional in order to analyse both experimental and numerical values. Solutions to second order diffusion equation are calculated in the framework of a dedicated method that incorporates Finite Element Method. Moreover, optimised solutions can be attained by gradient type minimisation algorithms. Knowledge about diffusion coefficient for Fricke gel radiation detector might be helpful in accounting for effects regarding elapsed time between dosimeter irradiation and further analysis. Hence, corrections might be included

  3. DNA as a solar dosimeter in the ocean.

    Science.gov (United States)

    Regan, J D; Carrier, W L; Gucinski, H; Olla, B L; Yoshida, H; Fujimura, R K; Wicklund, R I

    1992-07-01

    Stratospheric ozone depletion may result in increased solar UV-B radiation to the ocean's upper layers and may cause deleterious effects on marine organisms. The primary UV-B damage induced in biological systems is to DNA. While physical measurements of solar UV-B penetration into the sea have been made, the effective depth and magnitude of actual DNA damage have not been determined. In the experiments reported here, UV-B-induced photoproducts (cyclobutane pyrimidine dimers) have been quantified in DNA molecules exposed to solar UV at the surface and at various depths in clear, tropical marine waters off Lee Stocking Island (23 degrees 45' N, 76 degrees 0.7' W), Exuma Cays, Bahamas. (14C)thymidine-labeled DNA or unlabeled bacteriophage phi X174 DNA was placed in specially designed quartz tubes at various depths for up to five days. Following exposure, DNA samples were removed to the laboratory where UV-B-induced pyrimidine dimers were quantified using a radiochromatographic assay, and bacteriophage DNA inactivation by solar UV-B was assayed by plaque formation in spheroplasts of Escherichia coli. Pyrimidine dimer induction was linear with time but the accumulation of dimers in DNA with time varied greatly with depth. Attenuation of dimer formation with depth of water was exponential. DNA at 3 m depth had only 17% of the pyrimidine dimers found at the surface. Bacteriophage phi X174 DNA, while reduced 96% in plaque-forming ability by a one day exposure to solar UV at the surface of the water, showed no effect on plaque formation after a similar exposure at 3 m. The data collected at the water's surface showed a "surface-enhanced dose" in that DNA damages at the real surface were greater than at the imaginary surface, which was obtained by extrapolating the data at depth to the surface. These results show the sensitivity of both the biochemical (dimers) and biological (phage plaques) DNA dosimeters. DNA dosimeters offer a sensitive, convenient and relatively

  4. FBX aqueous chemical dosimeter for measurement of dosimetric parameters

    Energy Technology Data Exchange (ETDEWEB)

    Moussous, O., E-mail: o.moussous@crna.d [Centre de Recherche Nucleaire d' Alger (CRNA), 02 Boulevard Frantz Fanon B.P. 399, 16000 Alger (Algeria); Medjadj, T. [Centre de Recherche Nucleaire d' Alger (CRNA), 02 Boulevard Frantz Fanon B.P. 399, 16000 Alger (Algeria); Benguerba, M. [Faculte de Physique, Universite des Sciences et de la Technologie Houari-Boumediene USTHB, Alger (Algeria)

    2011-02-15

    We investigated the ferrous sulphate-benzoic acid-xylenol orange (FBX) aqueous chemical dosimeter for measurement of dosimetric parameters such as the output factor, backscatter factor and lateral beam profiles for different square fields sizes for {sup 60}Co {gamma}-rays. A water phantom was employed to measure these parameters. An ionization chamber (IC) was used for calibration and comparison. A comparison of the resulting measurements with an ionization chamber's measured parameters showed good agreement. We thus believe that the tissue equivalent FBX dosimetry system can measure the dosimetric parameters for {sup 60}Co with reasonable accuracy.

  5. Design of an improved neutron dose equivalent dosimeter

    CERN Document Server

    Brushwood, J M; Spyrou, N M

    2002-01-01

    This paper describes the design and development of a new active area neutron dosimeter. The design incorporates a traditional central detector with a moderator/filter arrangement and a number of outer PIN type photodiodes sensitised to thermal neutrons by the application of a lithium fluoride converter. The outer thermal detectors allow the determination of the neutron radiation field characteristics. The experimental programme has demonstrated that such an arrangement is capable of discriminating between various neutron fields and the usefulness of MCNP4b as a design tool.

  6. Optimization of the obtaining method of CaSO{sub 4}: Dy + Ptfe dosimeters; Optimizacion del metodo de obtencion de dosimetros de CaSO{sub 4}: Dy + PTFE

    Energy Technology Data Exchange (ETDEWEB)

    Galicia A, J.; Rioja Ch, J.; Torijano C, E.; Azorin N, J., E-mail: blink19871@hotmail.com [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico)

    2012-10-15

    This work contain the obtained results of studying the response when irradiating to different dose of X-rays, dosimeters of CaSO{sub 4}: Dy + Ptfe using different lapses of time in their preparation (a lot of selected dosimeters of an elaboration process of 3 days and another of an elaboration process of 2 hours). For the elaboration of the powdered material, the evaporation method was used; the irradiation were carried out in a lineal accelerator Elekta Synergy property of the National Medical Center, 20 de November. The similarities and differences are shown among the two dosimeters lots together with an analysis of the shine curves and of calibration selecting those that presented a better behaviour and a more rea liable response. (Author)

  7. Photoluminescence response of colloidal quantum dots on VO2 film across metal to insulator transition.

    Science.gov (United States)

    Kuznetsov, Sergey N; Cheremisin, Alexander B; Stefanovich, Genrikh B

    2014-01-01

    We have proposed a method to probe metal to insulator transition in VO2 measuring photoluminescence response of colloidal quantum dots deposited on the VO2 film. In addition to linear luminescence intensity decrease with temperature that is well known for quantum dots, temperature ranges with enhanced photoluminescence changes have been found during phase transition in the oxide. Corresponding temperature derived from luminescence dependence on temperature closely correlates with that from resistance measurement during heating. The supporting reflectance data point out that photoluminescence response mimics a reflectance change in VO2 across metal to insulator transition. Time-resolved photoluminescence study did not reveal any significant change of luminescence lifetime of deposited quantum dots under metal to insulator transition. It is a strong argument in favor of the proposed explanation based on the reflectance data. 71.30. + h; 73.21.La; 78.47.jd.

  8. Pyroelectric response in crystalline hafnium zirconium oxide (Hf1-xZrxO2) thin films

    Science.gov (United States)

    Smith, S. W.; Kitahara, A. R.; Rodriguez, M. A.; Henry, M. D.; Brumbach, M. T.; Ihlefeld, J. F.

    2017-02-01

    Pyroelectric coefficients were measured for 20 nm thick crystalline hafnium zirconium oxide (Hf1-xZrxO2) thin films across a composition range of 0 ≤ x ≤ 1. Pyroelectric currents were collected near room temperature under zero applied bias and a sinusoidal oscillating temperature profile to separate the influence of non-pyroelectric currents. The pyroelectric coefficient was observed to correlate with zirconium content, increased orthorhombic/tetragonal phase content, and maximum polarization response. The largest measured absolute value was 48 μCm-2 K-1 for a composition with x = 0.64, while no pyroelectric response was measured for compositions which displayed no remanent polarization (x = 0, 0.91, and 1).

  9. Quick pH-responsive Films Prepared from Urethane Acrylate Anionomers Under UV Radiation and Their Responsive Performances

    Institute of Scientific and Technical Information of China (English)

    TANG Li-ming; DAI Yu; Fang Yu

    2004-01-01

    Urethane acrylate anionomers(UAA) were prepared in various compositions by three steps. Under UV radiation, UAA formed pH-sensitive films with drying film thicknesses of 60, 200 and 330μm. The equilibrium swelling ratios(SR) of the films in various pH buffer solutions increased with the increase of the molecule weight of UAA. The influence of the film thicknesses on the swelling performances of the films was investigated. The film with a thickness of 60 μm could reach the equilibrium state in 2.5-3.5 min. A high SR was obtained for a thick film due to its low average network density. The cured film could swell reversibly and rapidly with the change of pH, which is important for a controlled release system.

  10. Performance evaluation of an improved optical computed tomography polymer gel dosimeter system for 3D dose verification of static and dynamic phantom deliveries.

    Science.gov (United States)

    Lopatiuk-Tirpak, O; Langen, K M; Meeks, S L; Kupelian, P A; Zeidan, O A; Maryanski, M J

    2008-09-01

    The performance of a next-generation optical computed tomography scanner (OCTOPUS-5X) is characterized in the context of three-dimensional gel dosimetry. Large-volume (2.2 L), muscle-equivalent, radiation-sensitive polymer gel dosimeters (BANG-3) were used. Improvements in scanner design leading to shorter acquisition times are discussed. The spatial resolution, detectable absorbance range, and reproducibility are assessed. An efficient method for calibrating gel dosimeters using the depth-dose relationship is applied, with photon- and electron-based deliveries yielding equivalent results. A procedure involving a preirradiation scan was used to reduce the edge artifacts in reconstructed images, thereby increasing the useful cross-sectional area of the dosimeter by nearly a factor of 2. Dose distributions derived from optical density measurements using the calibration coefficient show good agreement with the treatment planning system simulations and radiographic film measurements. The feasibility of use for motion (four-dimensional) dosimetry is demonstrated on an example comparing dose distributions from static and dynamic delivery of a single-field photon plan. The capability to visualize three-dimensional dose distributions is also illustrated.

  11. Optimization of synthesis conditions of PbS thin films grown by chemical bath deposition using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Yücel, Ersin, E-mail: dr.ersinyucel@gmail.com [Department of Physics, Faculty of Arts and Sciences, Mustafa Kemal University, 31034 Hatay (Turkey); Yücel, Yasin; Beleli, Buse [Department of Chemistry, Faculty of Arts and Sciences, Mustafa Kemal University, 31034 Hatay (Turkey)

    2015-09-05

    Highlights: • For the first time, RSM and CCD used for optimization of PbS thin film. • Tri-sodium citrate, deposition time and temperature were independent variables. • PbS thin film band gap value was 2.20 eV under the optimum conditions. • Quality of the film was improved after chemometrics optimization. - Abstract: In this study, PbS thin films were synthesized by chemical bath deposition (CBD) under different deposition parameters. Response surface methodology (RSM) was used to optimize synthesis parameters including amount of tri-sodium citrate (0.2–0.8 mL), deposition time (14–34 h) and deposition temperature (26.6–43.4 °C) for deposition of the films. 5-level-3-factor central composite design (CCD) was employed to evaluate effects of the deposition parameters on the response (optical band gap of the films). The significant level of both the main effects and the interaction are investigated by analysis of variance (ANOVA). The film structures were characterized by X-ray diffractometer (XRD). Morphological properties of the films were studied with a scanning electron microscopy (SEM). The optical properties of the films were investigated using a UV–visible spectrophotometer. The optimum amount of tri-sodium citrate, deposition time and deposition temperature were found to be 0.7 mL, 18.07 h and 30 °C respectively. Under these conditions, the experimental band gap of PbS was 2.20 eV, which is quite good correlation with value (1.98 eV) predicted by the model.

  12. Adaptation of a Pocket PC for Use as a Wearable Voice Dosimeter

    Science.gov (United States)

    Popolo, Peter S.; Svec, Jan G.; Titze, Ingo R.

    2005-01-01

    This article deals with the adaptation of a commercially available Pocket PC for use as a voice dosimeter, a wearable device that measures the vocal dose of teachers or other individuals on the job, at home, and elsewhere during the course of an entire day. An engineering approach for designing a voice dosimeter is described, and design data are…

  13. Longevity Tests of High-Sensitivity BD-PND Bubble Dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Radev, R; Carlberg, E

    2002-07-09

    Medium- and very-high-sensitivity neutron bubble dosimeters (BD-PNDs) made by Bubble Technology Industries (BTI) were used to study the life span of such dosimeters in a standard setup with a {sup 252}Cf source. Although data on the longevity of bubble dosimeters with low and medium sensitivity exist, such data for dosimeters with high and very high sensitivity are not readily available. The manufacturer guarantees optimum dosimeter performance for 3 months after receipt. However, it is important to know the change in the dosimeters' characteristics with time, especially after the first 3 months. The long-term performance of four sets of very high sensitivity and one set of medium-sensitivity bubble dosimeters was examined for periods of up to 13 months. During that time, the detectors were exposed and reset more than 20 times. Although departures from initial detection sensitivity were observed in several cases, the detectors indicated a significantly longer life span than stated in the manufacturer's warranty. In addition, the change in the number of bubbles and in evaluated neutron dose as a function of the time from the end of exposure until the dosimeters were read was investigated.

  14. [Estimation of personal dose based on the dependent calibration of personal dosimeters in interventional radiology].

    Science.gov (United States)

    Mori, Hiroshige; Koshida, Kichiro; Ichikawa, Katsuhiro

    2007-08-20

    The purpose of present study is, in interventional radiology (IVR), to elucidate the differences between each personal dosimeter, and the dependences and calibrations of area or personal dose by measurement with electronic dosimeters in particular. We compare space dose rate distributions measured by an ionization survey meter with the value measured by personal dosimeter: an optically stimulated luminescence, two fluoroglass, and two electronic dosimeters. Furthermore, with electronic dosimeters, we first measured dose rate, energy, and directional dependences. Secondly, we calibrated the dose rate measured by electronic dosimeters with the results, and estimated these methods with coefficient of determination and Akaike's Information Criterion (AIC). The results, especially in electronic dosimeters, revealed that the dose rate measured fell by energy and directional dependences. In terms of methods of calibration, the method is sufficient for energy dependence, but not for directional dependence, because of the lack of stable calibration. This improvement poses a question for the future. The study suggested that these dependences of the personal dosimeter must be considered when area or personal dose is estimated in IVR.

  15. Ceric and ferrous dosimeters show precision for 50-5000 rad range

    Science.gov (United States)

    Frigerio, N. A.; Henry, V. D.

    1968-01-01

    Ammonium thiocyanate, added to the usual ferrous sulfate dosimeter solution, yielded a very stable, precise and temperature-independent system eight times as sensitive as the classical Fricke system in the 50 to 5000 rad range. The ceric dosimeters, promising for use in mixed radiation fields, respond nearly independently of LET.

  16. A modified Fricke gel dosimeter for fast electron blood dosimetry

    Science.gov (United States)

    Del Lama, L. S.; de Góes, E. G.; Sampaio, F. G. A.; Petchevist, P. C. D.; de Almeida, A.

    2014-12-01

    It has been suggested for more than forty years that blood and blood components be irradiated before allogeneic transfusions for immunosuppressed patients in order to avoid the Transfusion-Associated Graft-versus-Host Disease (TA-GVHD). Whole blood, red blood cells, platelets and granulocytes may have viable T cells and should be irradiated before transfusion for different patient clinical conditions. According to international guides, absorbed doses from 25 up to 50 Gy should be delivered to the central middle plane of each blood bag. Although gamma and X-rays from radiotherapy equipments and dedicated cell irradiators are commonly used for this purpose, electron beams from Linear Accelerators (LINACs) could be used as well. In this work, we developed a methodology able to acquire dosimetric data from blood irradiations, especially after fast electrons exposures. This was achieved using a proposed Fricke Xylenol Gel (FXGp) dosimeter, which presents closer radiological characteristics (attenuation coefficients and stopping-powers) to the whole blood, as well as complete absorbed dose range linearity. The developed methodology and the FXGp dosimeter were also able to provide isodose curves and field profiles for the irradiated samples.

  17. A modified Fricke gel dosimeter for fast electron blood dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Del Lama, L.S., E-mail: lucasdellama@gmail.com [Departamento de Fsica, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo (FFCLRP/USP), Av. Bandeirantes, 3900, CEP 14040-901, Bairro Monte Alegre, Ribeirão Preto, São Paulo (Brazil); Góes, E.G. de [Instituto de Matemática, Estatística e Física, Universidade Federal de Rio Grande (IMEF/FURG), Av. Itália, km 8, CEP 96201-900, Bairro Carreiros, Rio Grande, Rio Grande do Sul (Brazil); Sampaio, F.G.A.; Petchevist, P.C.D.; Almeida, A. de [Departamento de Fsica, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo (FFCLRP/USP), Av. Bandeirantes, 3900, CEP 14040-901, Bairro Monte Alegre, Ribeirão Preto, São Paulo (Brazil)

    2014-12-15

    It has been suggested for more than forty years that blood and blood components be irradiated before allogeneic transfusions for immunosuppressed patients in order to avoid the Transfusion-Associated Graft-versus-Host Disease (TA-GVHD). Whole blood, red blood cells, platelets and granulocytes may have viable T cells and should be irradiated before transfusion for different patient clinical conditions. According to international guides, absorbed doses from 25 up to 50 Gy should be delivered to the central middle plane of each blood bag. Although gamma and X-rays from radiotherapy equipments and dedicated cell irradiators are commonly used for this purpose, electron beams from Linear Accelerators (LINACs) could be used as well. In this work, we developed a methodology able to acquire dosimetric data from blood irradiations, especially after fast electrons exposures. This was achieved using a proposed Fricke Xylenol Gel (FXG{sub p}) dosimeter, which presents closer radiological characteristics (attenuation coefficients and stopping-powers) to the whole blood, as well as complete absorbed dose range linearity. The developed methodology and the FXG{sub p} dosimeter were also able to provide isodose curves and field profiles for the irradiated samples.

  18. High-responsivity UV-Vis Photodetector Based on Transferable WS2 Film Deposited by Magnetron Sputtering.

    Science.gov (United States)

    Zeng, Longhui; Tao, Lili; Tang, Chunyin; Zhou, Bo; Long, Hui; Chai, Yang; Lau, Shu Ping; Tsang, Yuen Hong

    2016-01-29

    The two-dimensional layered semiconducting tungsten disulfide (WS2) film exhibits great promising prospects in the photoelectrical applications because of its unique photoelectrical conversion property. Herein, in this paper, we report the simple and scalable fabrication of homogeneous, large-size and transferable WS2 films with tens-of-nanometers thickness through magnetron sputtering and post annealing process. The produced WS2 films with low resistance (4.2 kΩ) are used to fabricate broadband sensitive photodetectors in the ultraviolet to visible region. The photodetectors exhibit excellent photoresponse properties, with a high responsivity of 53.3 A/W and a high detectivity of 1.22 × 10(11) Jones at 365 nm. The strategy reported paves new way towards the large scale growth of transferable high quality, uniform WS2 films for various important applications including high performance photodetectors, solar cell, photoelectrochemical cell and so on.

  19. Microwave Response of MgB2/Al2O3 Superconducting Thin Films by Microstrip Resonator Technique

    Institute of Scientific and Technical Information of China (English)

    SHI Li-Bin; ZHENG Yan; REN Jun-Yuan; LI Ming-Biao; ZHANG Feng-Yun; LI Bo-Xin; DONG Hai-Kuan

    2007-01-01

    Double-sided superconducting MgB2 thin films are deposited onto c-Al2O3 substrates by the hybrid physical chemical vapour deposition method. The microwave response of MgBz/Al2O3 is investigated by microstrip resonator technique. A grain-size model is introduced to the theory of microstrip resonators to analyse microwave properties of the films. We obtain effective penetration depth of the films at 0K (λe0 = 463 nm) and surface resistance (R3 = 1.52mΩ at 11 K and 8.73 GHz) by analysing the resonant frequency and unload quality factor of the microstrip resonator, which suggests that the impurities and disorders of grain boundaries of MgB2/Al2O3 result in increasing penetration depth and surface resistance of the films.

  20. OPTICAL PHASE CONJUGATION RESPONSE OF PHOTOINDUCED POLYMER FILMS CONTAINING AZOBENZENE MOIETIES WITH CHIRAL GROUP

    Institute of Scientific and Technical Information of China (English)

    Ze-da Xu; Yong Zhang; Xing-he Fan; Xin-hua Wan; Qi-feng Zhou

    2002-01-01

    An optically active monomer containing azobenzene moieties with chiral group (s-2-methyl-butyl), 4-[2-(methacryloyloxy)ethyloxy]-4'-(s-2-methyl-1-butyloxycarbonyl) azobenzene (M1) was synthesized. Polymer (PM1) possessing optical phase conjugated response was obtained by homopolymerization of the optically active monomer (M1) using free radical polymerization. The polymer was very soluble in common solvents and good optical quality films could be easily fabricated by spin coating. The optical phase conjugated responses of the polymer PM1 were measured by degenerate four-wave mixing (DFWM). In comparison with polymer containing no chiral group, it was found from the preliminary measurement of photoisomeric change that optical phase conjugated response of the PM1 in the long-range order hexagonal symmetry microstructure could be easily controlled by choosing the appropriate polarization direction of the irradiating beams (514.5 nm) and the irradiating number, presumably due to the chiral group in the PM1 molecular structure. For the case of the polymer investigated here, a chiral group side chain was introduced to increase optical phase conjugated response intensity with different polarization directions of the irradiating beams, which aims originally at searching for a new photoactive material.

  1. The response of quartz crystals coated with thin fatty acid film to organic gases

    CERN Document Server

    Jin, C N; Kim, K H; Kwon, Y S

    1999-01-01

    We tried to apply a quartz crystal as a sensor by using the resonant frequency and the resistance properties of quartz crystals. Four kinds of fatty acids that have the same head groups were coated on the surfaces of the quartz crystals, and the shift of the resonant frequency and the resistance were observed based on the lengths of the tail groups. Myristic acid (C sub 1 sub 4), palmitic acid (C sub 1 sub 6), stearic acid (C sub 1 sub 8), and arachidic acid (C sub 2 sub 0) were deposited on the surfaces of quartz crystals by using the Langmuir-Blodgett (LB) method. As a result, the resonant frequency change was more sensitive to high molecular-weight fatty acids than to low molecular-weight ones. We also observed the effect of temperature on stearic acid LB films, and the response properties of quartz crystals coated with stearic-acid LB films to organic gases were investigated. As a result, the sensitivity of quartz crystals to organic gases was higher for higher molecular-weight gas, and we found that quar...

  2. Cosmopolitan communication online: YouTube responses to the anti-Islam film Fitna.

    Science.gov (United States)

    Mihelj, Sabina; van Zoonen, Liesbet; Vis, Farida

    2011-12-01

    In 2008, a Dutch member of parliament released a short anti-Islamic film entitled Fitna, which stirred a huge public controversy and provoked public condemnations around the world. In response to the film, hundreds of videos were uploaded on YouTube, mostly with the aim to provide a more positive representation of Islam, express support for the author and his views, or defend his freedom of speech. Drawing on interviews with YouTube users who posted the videos, this paper reflects on the capacity of the Internet to sustain cosmopolitan communication and examines how cosmopolitan attitudes and practices on-line differ depending on the participants' cultural and social background, especially their religious affiliations. Particular attention is paid to how the opportunities for cosmopolitan communication are shaped by the unequal distribution of cosmopolitan attitudes and practices among groups, and by global inequalities of power. In addressing these issues, the paper also engages with broader debates about cosmopolitanism, and argues for an understanding of cosmopolitanism as a quest for universalism, which remains anchored in the particular, but involves communication across difference, and requires openness to the possibility that the other is right.

  3. Response of radiochromic dye films to low energy heavy charged particles

    CERN Document Server

    Buenfil, A E; Gamboa-Debuen, I; Aviles, P; Avila, O; Olvera, C; Robledo, R; Rodriguez-Ponce, M; Mercado-Uribe, H; Rodriguez-Villafuerte, M; Brandan, M E

    2002-01-01

    We have studied the possible use of radiochromic dye films (RCF) as heavy charged particle dosemeters. We present the results of irradiating two commercial RCF (GafChromic HD-810 and MD-55-1) with 1.5, 2.9 and 4.4 MeV protons, 1.4, 2.8, 4.7, 5.9, 6.8 MeV sup 4 He ions and 8.5 and 12.4 MeV sup 1 sup 2 C ions, at proton doses from about 1 Gy up to 3 kGy, helium ions doses from 3 Gy to 5 kGy and carbon ion doses from 30 Gy to 20 kGy. The films were scanned and digitized using commercial equipment. For a given particle, the response per unit dose at different energies indicates an energy dependence of the sensitivity, which is discussed. Comparison was made for the use of a standard spectrophotometer to obtain optical density readings versus a white light scanner.

  4. First dose-map measured with a polycrystalline diamond 2D dosimeter under an intensity modulated radiotherapy beam

    Energy Technology Data Exchange (ETDEWEB)

    Scaringella, M., E-mail: scaringella@gmail.com [Università di Firenze, Dipartimento di Ingegneria dell’Informazione, Firenze (Italy); Zani, M. [INFN Sezione di Firenze, Sesto Fiorentino, Firenze (Italy); Università di Firenze, Dipartimento di Scienze Biomediche, Sperimentali e Cliniche, Firenze (Italy); Baldi, A. [Università di Firenze, Dipartimento di Ingegneria Industriale, Firenze (Italy); Bucciolini, M. [INFN Sezione di Firenze, Sesto Fiorentino, Firenze (Italy); Università di Firenze, Dipartimento di Scienze Biomediche, Sperimentali e Cliniche, Firenze (Italy); Pace, E.; Sio, A. de [INFN Sezione di Firenze, Sesto Fiorentino, Firenze (Italy); Università di Firenze, Dipartimento di Fisica e Astronomia, Sesto Fiorentino, Firenze (Italy); Talamonti, C. [INFN Sezione di Firenze, Sesto Fiorentino, Firenze (Italy); Università di Firenze, Dipartimento di Scienze Biomediche, Sperimentali e Cliniche, Firenze (Italy); Bruzzi, M. [INFN Sezione di Firenze, Sesto Fiorentino, Firenze (Italy); Università di Firenze, Dipartimento di Fisica e Astronomia, Sesto Fiorentino, Firenze (Italy)

    2015-10-01

    A prototype of bidimensional dosimeter made on a 2.5×2.5 cm{sup 2} active area polycrystalline Chemical Vapour Deposited (pCVD) diamond film, equipped with a matrix of 12×12 contacts connected to the read-out electronics, has been used to evaluate a map of dose under Intensity Modulated Radiation Therapy (IMRT) fields for a possible application in pre-treatment verifications of cancer treatments. Tests have been performed under a 6–10 MVRX beams with IMRT fields for prostate and breast cancer. Measurements have been taken by measuring the 144 pixels in different positions, obtained by shifting the device along the x/y axes to span a total map of 14.4×10 cm{sup 2}. Results show that absorbed doses measured by our pCVD diamond device are consistent with those calculated by the Treatment Planning System (TPS)

  5. A computational study of the piezoelectric response due to the material effect in periodic, single island thin films and the geometric effect in periodic, bi-island thin films

    Energy Technology Data Exchange (ETDEWEB)

    Liu, B. [Department of Applied Science, University of Arkansas at Little Rock, 2801 South University, ETAS 575, Little Rock, AR 72204-1099 (United States); Bhattacharyya, A., E-mail: axbhattachar@ualr.ed [Department of Applied Science, University of Arkansas at Little Rock, 2801 South University, ETAS 575, Little Rock, AR 72204-1099 (United States)

    2010-05-03

    The electromechanical response of a square-periodic array of circular piezoelectric (PE) thin films alternating with non-piezoelectric (NPE) films is studied in this paper. The material effects are studied for four film/substrate combinations in absence of NPE films for which it is found that if d{sub zxx} << d{sub zzz} (z-axis being normal to the interfacial plane between the film and the substrate), it results in reduced substrate bending leading to reduced degradation in the electromechanical response of the thin film. The bi-island structure is studied for zinc oxide on strontium titanate, and, in general, it is seen that the NPE films not only reduce degradation of the electromechanical response of the PE films but also increase their internal stresses; the effect on the former is less than the latter. These effects are most prominent when the circular NPE thin films fill the space between the PE thin films and are elastically very stiff compared to the substrate.

  6. Development of a new dosimeter of EPR based on lactose; Desarrollo de un nuevo dosimetro de RPE basado en lactosa

    Energy Technology Data Exchange (ETDEWEB)

    Cruz C, L.; Torijano C, E.; Azorin N, J.; Aguirre G, F. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Cruz Z, E., E-mail: eftc@xanum.uam.mx [UNAM, Instituto de Ciencias Nucleares, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2014-08-15

    50 years have passed since was proposed using the amino acid alanine as dosimeter advantage the phenomenon of electron paramagnetic resonance (EPR); this dosimetric method has reached a highly competitive level regarding others dosimetry classic methods, for example the thermoluminescence or the use of Fricke dosimeters, to measure high dose of radiation. In this type of materials, the free radicals induced by the radiation are stable and their concentration is proportional to the absorbed dose may be determined by the amplitude pick to pick of the first derived of the EPR absorption spectrum. The obtained results studying the EPR response of lactose tablets elaborated in the Universidad Autonoma Metropolitana, Unidad Iztapalapa are presented. The tablets were irradiated with gamma radiation of {sup 60}Co in the irradiator Gamma beam 651-Pt of the Instituto de Ciencias Nucleares de la Universidad Nacional Autonoma de Mexico to a dose rate of 8 kGy-h{sup -1} and their EPR response in a EPR spectrometer e-scan Bruker. The obtained response in function of the dose was lineal in the interval of 1 at 10 kGy. The lactose sensibility was compared with the l-alanine, used as reference, and the result was consistently 0.25 of this. Due to the linearity shown in the interval of used dose and their low production cost, we conclude that the lactose is a promissory option for the dosimetry of high dose of radiation. (author)

  7. A sensitive YBaCuO thin film bolometer with ultrawide wavelength response

    Science.gov (United States)

    Dwir, B.; Pavuna, D.

    1992-11-01

    We have constructed two types of high-temperature superconducting bolometers, whose performance is essentially wavelength independent from 0.6 to 450 microns: the first is a microbridge, of dimensions 20 x 20 microns, and the second is a meander, covering a region of about 1 sq mm. Both were fabricated by photolithography of a superconducting YBaCuO thin film on SrTiO3. The bolometers are current biased, and the ac voltage induced by the chopped radiation is measured using lock-in detection. Operating optimally in the vicinity of the transition temperature (90 K), the first bolometer shows responsivity S about 1 mV/(W/sq cm), while the second gives S about 800 V/W. The response of the first bolometer for various chopping frequencies is basically S about 1/sq rt f, which makes it usuable at frequencies up to over 50 kHz, while the second bolometer has a chopping-frequency response that is basically S about 1/f, with a cutoff frequency near 0.01 Hz.

  8. Procedure for the delivering of personal short-term visitor dosimeters

    CERN Multimedia

    2016-01-01

    Update of the administrative procedure for delivering a personal short-term visitor dosimeter to associated members of CERN’s personnel.   Associated members of the CERN personnel may request a short term visitor dosimeter if working only in Supervised Radiation Areas and for a period of less than two months in a calendar year. Such a dosimeter is delivered without the need to provide the usual regular documents: radiation passport, certificate from the home institute or medical certificate. Periodic verification will ensure that holders of these personal dosimeters do not exceed the maximum allowed personal dose for this type of dosimeter, which is the same as the limit for members of the public at 1 mSv per year. From now on, the two-month period can be spread over a calendar year, offering greater flexibility to users coming to CERN for multiple short periods. Please return unused dosimeters Persons leaving CERN for a period of more than one month should return their dosimeter to the D...

  9. [Is it really not possible to use electronic personal dosimeters in clinical exposure situations?].

    Science.gov (United States)

    Borowski, M; Poppe, B; Looe, H K; von Boetticher, H

    2010-09-01

    Due to significant measuring inaccuracies that can occur under certain conditions, the use of electronic personal dosimeters in statutory measurements in X-ray diagnostics is currently legally restricted. The present study investigates the clinically relevant situations in which measurement errors of more then 20 % can be anticipated. Four series of experiments were made, comparing the results of the electronic personal dosimeter EPD Mk2.3 to those of reference dosimeters (TLDs and diagnostic dosimeters). On the one hand, personal doses have been determined in the routine operation of controlled areas in various departments. On the other hand, measurements on phantoms have been conducted in extreme but realistic situations under radiation protection. Experiments were conducted in unweakened scattered radiation as well as in unattenuated and attenuated direct radiation. The tested electronic personal dosimeter type meets the requirements regarding measurement accuracy for "official" personal dosimeters in all of the examined clinically relevant scattered radiation fields. Only if exposed to radiation directly, an underestimation of the dose can occur and can be greater than 90 %. In the range of scattered radiation of diagnostic X-ray equipment, even in pulsed fields, the use of electronic personal dosimeters is reasonable. Considerable measurement errors can only arise in radiation fields that are not realistic under regular conditions and even in connection with most accidents. Georg Thieme Verlag KG Stuttgart, New York.

  10. Film dosimetry calibration method for pulsed-dose-rate brachytherapy with an 192Ir source.

    Science.gov (United States)

    Schwob, Nathan; Orion, Itzhak

    2007-05-01

    192Ir sources have been widely used in clinical brachytherapy. An important challenge is to perform dosimetric measurements close to the source despite the steep dose gradient. The common, inexpensive silver halide film is a classic two-dimensional integrator dosimeter and would be an attractive solution for these dose measurements. The main disadvantage of film dosimetry is the film response to the low-energy photon. Since the photon energy spectrum is known to vary with depth, the sensitometric curves are expected to be dependent on depth. The purpose of this study is to suggest a correction method for silver halide film dosimetry that overcomes the response changes at different depths. Sensitometric curves have been obtained at different depths with verification film near a 1 Ci 192Ir pulsed-dose-rate source. The depth dependence of the film response was observed and a correction function was established. The suitability of the method was tested through measurement of the radial dose profile and radial dose function. The results were compared to Monte Carlo-simulated values according to the TG43 formalism. Monte Carlo simulations were performed separately for the beta and gamma source emissions, using the EGS4 code system, including the low-energy photon and electron transport optimization procedures. The beta source emission simulation showed that the beta dose contribution could be neglected and therefore the film-depth dependence could not be attributed to this part of the source radioactivity. The gamma source emission simulations included photon-spectra collection at several depths. The results showed a depth-dependent softening of the photon spectrum that can explain the film-energy dependence.

  11. Development of a multichannel dosimeter for radiotherapy; Desenvolvimento de um dosimetro multicanal para radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Menezes, Claudio Jose Mesquita

    2000-06-01

    In radiotherapy, verification of the patient dose is of great important for the success of the treatment. Uncertainties in the evaluation of this dose can produce serious complications such as the loss of the control of the disease and damage to normal tissue. Semiconductor detectors present advantages over other types of radiation detectors such as ionization chambers and thermoluminescent dosimeters including small dimensions, high sensitivity and fast response. In this work, a multichannel dosimetric system is linear with dose, for a 6 MV x-ray beam and also with a beam of cobalt-60 gamma rays. The coefficients of determination of the calibration curves were better then 0,9998 in all cases. The four sensors presented similar response with the dose for different field sizes. The variation of the response was smaller than 1%. In a related study, depth dose was measured, and the results showed a good agreement compared to theoretical values. The angular response of the detectors showed a variation of 7% for angles of 45 deg C. Using the Anderson Random phantom, dose at the isocenter was determined from measurements of the surface dose. From the results obtained it can be concluded that the dosimetric system developed is adequate for the evaluation of many parameters in radiation fields used in radiotherapy. This system can be used to measure the patient entrance dose under treatment conditions, and the equipment can be used in the radiotherapy quality assurance program. (author)

  12. Epitaxial Growth of Large-Grain NiSe Films by Solid-State Reaction for High-Responsivity Photodetector Arrays.

    Science.gov (United States)

    Cai, Caoyuan; Ma, Yang; Jeon, Jaeho; Huang, Fan; Jia, Feixiang; Lai, Shen; Xu, Zhihao; Wu, Congjun; Zhao, Ruiqi; Hao, Yufeng; Chen, Yiqing; Lee, Sungjoo; Wang, Min

    2017-05-01

    Film-based photodetectors have shown superiority for the fabrication of photodetector arrays, which are desired for integrating photodetectors into sensing and imaging systems, such as image sensors. But they usually possess a low responsivity due to low carrier mobility of the film consisting of nanocrystals. Large-grain semiconductor films are expected to fabricate superior-responsivity photodetector arrays. However, the growth of large-grain semiconductor films, normally with a nonlayer structure, is still challenging. Herein, this study introduces a solid-state reaction method, in which the growth rate is supposed to be limited by diffusion and reaction rate, for interface-confined epitaxial growth of nonlayer structured NiSe films with grain size up to micrometer scale on Ni foil. Meanwhile, patterned growth of NiSe films allows the fabrication of NiSe film based photodetector arrays. More importantly, the fabricated photodetector based on as-grown high-quality NiSe films shows a responsivity of 150 A W(-1) in contrast to the value of 0.009 A W(-1) from the photodetector based on as-deposited NiSe film consisting of nanocrystals, indicating a huge responsivity-enhancement up to four orders of magnitude. It is ascribed to the enhanced charge carrier mobility in as-grown NiSe films by dramatically decreasing the amount of grain boundary leading to scattering of charge carrier. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Oscillometric and conductometric analysis of aqueous and organic dosimeter solutions

    DEFF Research Database (Denmark)

    Kovacs, A.; Slezsak, I.; McLaughlin, W.L.

    1995-01-01

    Conductometric and oscillometric evaluation methods have earlier been developed to determine absorbed dose in the ethanol-monochlorobenzene dosimeter solution. Recent investigations on the same solution as well as on alanine solutions included the study of the possible use of different type...... ''conductometric'' electrodes and the study of the effect of frequency on the sensitivity of the method. On the basis of these investigations an oscillometric reader has been designed and tested. The same evaluation methods have been tested on the irradiated aqueous alanine solutions, aiming also at the study...... of the applicable concentration of the alanine solute and the dose (1 to 50 kGy) and dose-rate range using both electron (2.6 mu s at 13 mu A to 4 mu s at 1.0 A pulse length and beam current) and gamma radiation (0.13 to 30 kGy h(-1))....

  14. Dual frequency cavitation event sensor with iodide dosimeter.

    Science.gov (United States)

    Ebrahiminia, Ali; Mokhtari-Dizaji, Manijhe; Toliyat, Tayebeh

    2016-01-01

    The inertial cavitation activity depends on the sonication parameters. The purpose of this work is development of dual frequency inertial cavitation meter for therapeutic applications of ultrasound waves. In this study, the chemical effects of sonication parameters in dual frequency sonication (40 kHz and 1 MHz) were investigated in the progressive wave mode using iodide dosimetry. For this purpose, efficacy of different exposure parameters such as intensity, sonication duration, sonication mode, duty factor and net ultrasound energy on the inertial cavitation activity have been studied. To quantify cavitational effects, the KI dosimeter solution was sonicated and its absorbance at a wavelength of 350 nm was measured. The absorbance values in continuous sonication mode was significantly higher than the absorbance corresponding to the pulsed mode having duty factors of 20-80% (plevel intensity (sensor can be useful for ultrasonic treatments.

  15. [AOR characterization and zoning: a dosimeter for blue light].

    Science.gov (United States)

    Dario, R; Uva, J; Di Lecce, V; Quarto, A

    2011-01-01

    The paper presents the results obtained thanks to an innovative experimental device for the assessment of artificial optical radiation (AOR) exposure in workplace. This . device was developed by 'Politecnico di Bari-DIASS'. The wearable personal dosimeter has three sensors: one is used for measuring head position/movement, therefore there is a color light sensor to determine the AOR and finally there is a video camera to localize sources. Our system is connected to a netbook via USB cable that allows one to obtain the real and extimated value of worker's exposure, also with "augmented reality". The aim of this paper is realizing work place safety zoning for the classifacation of not only specific dangerous areas through the analysis of overlapping information from the device.

  16. A BCCD-based dosimeter for mixed radiation fields

    Science.gov (United States)

    Pierschel, M.; Ehwald, K.-E.; Heinemann, B.; Januschewski, F.; Schmitz, T.; Schröder, O.

    1993-03-01

    The development of a personal dosimeter based on a BCCD-detector for mixed neutron and gamma radiation in the energy range from thermal energy to 20 MeV for neutrons respectively 30 keV to a few MeV for gammas will be presented. The detector has to give information on the total radiation dose, D, and on the radiation quality. Both peaces of information are required to determine the directional dose equivalent. The basic radiation physics requirements for the detector as well as a concept of a buried channel CCD-matrix for radiation applications including the technology process will be described. A two dimensional device simulation package was used for both optimization of the charge storage nodes including free charge transfer and the basic electronic processes depending on radiation interaction with silicon.

  17. An evaluation of the BD-100R rechargeable neutron bubble dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Millett, M.; Munno, F.; Ebert, D.; Nelson, M. (Univ. of Maryland, College Park (USA))

    1991-03-01

    The purpose of this paper is to present data gathered in the evaluation of the BD-100R neutron bubble dosimeter done at the University of Maryland and the Naval Research Lab. The performance of 12 dosimeters has been followed over 15 exposure-recharge cycles under a wide range of exposure conditions. Included in this paper are the results from tests on dose rate dependence, neutron energy dependence, beta and gamma exposure, and recharge cycle performance. A statistical analysis of the reusability performance of the dosimeter as a function of dose equivalent is also presented.

  18. FILM TOURISM RESPONSES TO THE TOURIST’S EXPECTATIONS - NEW CHALLENGES

    Directory of Open Access Journals (Sweden)

    Anna POLIANSKAIA

    2016-05-01

    Full Text Available This paper sheds light on the world of film tourism, the connection between the film as an image-making tool and the attractiveness of tourism destinations. In this context the present research analyses the phenomenon of film-induced tourism. Even though the phenomenon of the film tourism has been recognized, there are still few profound studies and a lack of the statistical data. However, the evidence of existence of such a phenomenon as film-induced tourism is incontrovertible. Thus, the little statistical data available on this topic indicates that such countries as UK, Australia, and New Zealand lead the way from the point of view of the film tourism. Existence of this type of tourism and its potentially significant economic value make understanding the drivers of film-induced tourism extremely important to know.

  19. Calibration factors for the SNOOPY - NP-100 neutron dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Moscu, D.F. [Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario, L8S 4L8 (Canada)], E-mail: moscudf@mcmaster.ca; McNeill, F.E. [Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario, L8S 4L8 (Canada); Chase, J. [Radiation Protection Division, Ontario Power Generation, Whitby, Ontario, L1N 9E3 (Canada)

    2007-10-15

    Within CANDU nuclear power facilities, only a small fraction of workers are exposed to neutron radiation. For these individuals, roughly 4.5% of the total radiation equivalent dose is the result of exposure to neutrons. When this figure is considered across all workers receiving external exposure of any kind, only 0.25% of the total radiation equivalent dose is the result of exposure to neutrons. At many facilities, the NP-100 neutron dosimeter, manufactured by Canberra Industries Incorporated, is employed in both direct and indirect dosimetry methods. Also known as 'SNOOPY', these detectors undergo calibration, which results in a calibration factor relating the neutron count rate to the ambient dose equivalent rate, using a standard Am-Be neutron source. Using measurements presented in a technical note, readings from the dosimeter for six different neutron fields in six source-detector orientations were used, to determine a calibration factor for each of these sources. The calibration factor depends on the neutron energy spectrum and the radiation weighting factor to link neutron fluence to equivalent dose. Although the neutron energy spectra measured in the CANDU workplace are quite different than that of the Am-Be calibration source, the calibration factor remains constant - within acceptable limits - regardless of the neutron source used in the calibration; for the specified calibration orientation and current radiation weighting factors. However, changing the value of the radiation weighting factors would result in changes to the calibration factor. In the event of changes to the radiation weighting factors, it will be necessary to assess whether a change to the calibration process or resulting calibration factor is warranted.

  20. Co-sputtered metal and polymer nanocomposite films and their electrical responses for gas sensing application

    Energy Technology Data Exchange (ETDEWEB)

    Rujisamphan, Nopporn [Department of Physics, Faculty of Science, King Mongkut' s University of Technology Thonburi, Bangkok 10140 (Thailand); Murray, Roy E. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Deng, Fei [Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716 (United States); Supasai, Thidarat, E-mail: fscitrs@ku.ac.th [Department of Materials Science, Faculty of Science, Kasetsart University, Bangkok 10900 (Thailand)

    2016-04-15

    Graphical abstract: - Highlights: • The well-controlled Ti–PTFE composite films were prepared by co-sputtering. • Ti clusters showed particle sizes varied between 10 and 30 nm in the PTFE matrix. • The swelling of polymer is the driving force to change interparticle distance and therefore a change in resistance. • The sensitivities of the Ti–PTFE devices were found to be in a range of 1.01–1.04. - Abstract: Titanium and polytetrafluoroethylene (Ti–PTFE) nanocomposite thin films were successfully fabricated on glass substrates using a combination of dc and rf magnetron sputtering. When the Ti–PTFE composites were prepared at below the percolation threshold i.e. 27% metal volume filling (F), Ti clusters with the average sizes of 7 ± 2 nm were found. As the Ti content was increased above the percolation threshold (F = 62%), the connecting regions of Ti were formed within the polymer matrix and the electrical property changed rapidly from insulator-like to metal-like properties. The Ti–PTFE composites prepared near the percolation threshold showed the electrical response to different volatile organic compounds (VOCs). The sensitivity significantly depended upon the VOCs concentrations. These composites devices showed the presence of distinct chemical bonds of C−C, C−CF, C−F and CF{sub 2} and TiF in TiO{sub 2} on the surface as investigated by X-ray photoelectron spectroscopy (XPS) while the surface morphology, characterized by atomic force microscopy (AFM) presented the root mean square (RMS) surface roughness of 13.3 nm. Cross-section transmission electron microscopy (TEM) images of the device revealed Ti clusters dispersed in PTFE matrix with particle sizes varied between 10 nm and 30 nm.

  1. A Rapid Response Thin-Film Plasmonic-Thermoelectric Light Detector

    Science.gov (United States)

    Pan, Ying; Tagliabue, Giulia; Eghlidi, Hadi; Höller, Christian; Dröscher, Susanne; Hong, Guo; Poulikakos, Dimos

    2016-11-01

    Light detection and quantification is fundamental to the functioning of a broad palette of technologies. While expensive avalanche photodiodes and superconducting bolometers are examples of detectors achieving single-photon sensitivity and time resolutions down to the picosecond range, thermoelectric-based photodetectors are much more affordable alternatives that can be used to measure substantially higher levels of light power (few kW/cm2). However, in thermoelectric detectors, achieving broadband or wavelength-selective performance with high sensitivity and good temporal resolution requires careful design of the absorbing element. Here, combining the high absorptivity and low heat capacity of a nanoengineered plasmonic thin-film absorber with the robustness and linear response of a thermoelectric sensor, we present a hybrid detector for visible and near-infrared light achieving response times of the order of 100 milliseconds, almost four times shorter than the same thermoelectric device covered with a conventional absorber. Furthermore, we show an almost two times higher light-to-electricity efficiency upon replacing the conventional absorber with a plasmonic absorber. With these improvements, which are direct results of the efficiency and ultra-small thickness of the plasmonic absorber, this hybrid detector constitutes an ideal component for various medium-intensity light sensing applications requiring spectrally tailored absorption coatings with either broadband or narrowband characteristics.

  2. Application of Response Surface Methodology in Development of Sirolimus Liposomes Prepared by Thin Film Hydration Technique

    Directory of Open Access Journals (Sweden)

    Saeed Ghanbarzadeh

    2013-04-01

    Full Text Available Introduction: The present investigation was aimed to optimize the formulating process of sirolimus liposomes by thin film hydration method. Methods: In this study, a 32 factorial design method was used to investigate the influence of two independent variables in the preparation of sirolimus liposomes. The dipalmitoylphosphatidylcholine (DPPC /Cholesterol (Chol and dioleoyl phosphoethanolamine(DOPE /DPPC molar ratios were selected as the independent variables. Particle size (PS and Encapsulation Efficiency (EE % were selected as the dependent variables. To separate the un-encapsulated drug, dialysis method was used. Drug analysis was performed with a validated RP-HPLC method. Results: Using response surface methodology and based on the coefficient values obtained for independent variables in the regression equations, it was clear that the DPPC/Chol molar ratio was the major contributing variable in particle size and EE %. The use of a statistical approach allowed us to see individual and/or interaction effects of influencing parameters in order to obtain liposomes with desired properties and to determine the optimum experimental conditions that lead to the enhancement of characteristics. In the prediction of PS and EE % values, the average percent errors are found to be as 3.59 and 4.09%. This value is sufficiently low to confirm the high predictive power of model. Conclusion: Experimental results show that the observed responses were in close agreement with the predicted values and this demonstrates the reliability of the optimization procedure in prediction of PS and EE % in sirolimus liposomes preparation.

  3. Qualification of the monitor Pug-7N like dosimeter for neutrons; Habilitacion del monitor PUG-7N como dosimetro para neutrones

    Energy Technology Data Exchange (ETDEWEB)

    Benites R, J. L. [Centro Estatal de Cancerologia de Nayarit, Av. Enfermeria, Fracc. Fray Junipero Serra, 63000 Tepic, Nayarit (Mexico); Vega C, H. R.; Murillo O, R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Velazquez F, J. B., E-mail: jlbenitesr@prodigy.net.mx [Universidad Autonoma de Nayarit, Postgrado CBAP, Carretera Tepic Compostela Km. 9, Xalisco, Nayarit (Mexico)

    2011-10-15

    By means of an inter-comparison method, the monitor for neutrons Pug-7N was enabled like dosimeter for neutrons of two magnitudes: the environmental equivalent dose, H*(10), and the H equivalent dose. The monitor Pug-7N has a plastic detector of scintillation Pns-20 that can be used inside or outside of its polyethylene cylindrical moderator. This designed to detect the neutrons presence that is shown in ana logical form by means of a fast count. Although the instrument is useful to detect the neutrons presence its design it does not allow to estimate the dose. With the purpose of enabling it as dosimeter for neutrons, their response was compared with the response of the area monitor for neutrons Bert hold Lb 6411 and Eberline NRD model Asp-1. Under the same irradiation conditions the 3 instruments were exposed to a source of {sup 241}AmBe of 3.7E(9) Bq (100 mCi) of activity whose spectrum and dosimetric magnitudes were determined with a spectrometric system of Bonner spheres with scintillator of {sup 6}Lil(Eu) and the NSDUAZ code. Conversion factors of H*(10)/cpm and H/cpm were obtained for the two options of the monitor detector Pug-7N, with this procedure the monitor Pug-7N besides determining the presence of neutrons, it has been enabled for their use as dosimeter for neutrons. (Author)

  4. The relationship of over density to overexposure each film/screen systems in chest radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Min; Huo Joon [Korea University, Seoul (Korea, Republic of); Taro, Hayash; Yuji, Ishida; Tatsuya, Sakurai [The Chemotherapeutic Istitute Hospital, Tokyo (Japan)

    1999-06-01

    This study is to calculate the exposed radiation dose using Bit method, NDD calculation method and monogram method without dosimeter. In addition,we can calculate the radiation dose from x-ray film density as a film badge. The authors examined the entrance skin dose from 2 {approx} 3 intercostal chest x-ray film density. We also studied the relationship between film density and equivalent dose in the each screen film system under the different radiation quality and the poor geometry condition of grid ratio. As results, we established the deductive method to define the entrance skin dose from chest x-ray film density. The error range was found in the range -13 percent {approx} +17 percent for between deductive entrance skin dose and the 2 {approx} 3 inter coastal chest x-ray film density to actual detective radiation dose with dosimeter. (author)

  5. Investigation of neutron converters for production of optically stimulated luminescence (OSL) neutron dosimeters using Al{sub 2}O{sub 3}:C

    Energy Technology Data Exchange (ETDEWEB)

    Mittani, J.C.R. [Department of Physics, Oklahoma State University, Stillwater, OK 74078-3072 (United States); Silva, A.A.R. da [Department of Physics, Oklahoma State University, Stillwater, OK 74078-3072 (United States); Vanhavere, F. [SCK.CEN, Belgian Nuclear Research Centre, Boeretang 200, 2400 Mol (Belgium); Akselrod, M.S. [Landauer, Inc., Stillwater Crystal Growth Division, 723 1/2 Eastgate Rd., Stillwater, OK 74074 (United States); Yukihara, E.G. [Department of Physics, Oklahoma State University, Stillwater, OK 74078-3072 (United States)]. E-mail: eduardo.yukihara@okstate.edu

    2007-07-15

    This paper presents the optically stimulated luminescence (OSL) properties of neutron dosimeters in powder and in the form of pellets prepared with a mixture of Al{sub 2}O{sub 3}:C and neutron converters. The neutron converters investigated were high density polyethylene (HDPE), lithium fluoride (LiF), lithium fluoride 95% enriched with {sup 6}Li ({sup 6}LiF), lithium carbonate 95% enriched with {sup 6}Li ({sup 6}Li{sub 2}CO{sub 3}), boric acid enriched with 99% of {sup 10}B (H{sub 3}{sup 10}BO{sub 3}) and gadolinium oxide (Gd{sub 2}O{sub 3}). The proportion of Al{sub 2}O{sub 3}:C and neutron converter in the mixture was varied to optimize the total OSL signal and neutron sensitivity. The neutron sensitivity and dose-response were determined for the OSL dosimeters using a bare {sup 252}Cf source and compared to the response of Harshaw TLD-600 and TLD-700 dosimeters ({sup 6}LiF:Mg,Ti and {sup 7}LiF:Mg,Ti). The results demonstrate the possibility of developing an OSL dosimeter made of Al{sub 2}O{sub 3}:C powder and neutron converter with a neutron sensitivity (defined as the ratio between the {sup 60}Co equivalent gamma dose and the reference neutron absorbed dose) and neutron-gamma discrimination comparable to the TLD-600/TLD-700 combination. It was shown that the shape of the OSL decay curves varied with the type of the neutron converter, demonstrating the influence of the energy deposition mechanism and ionization density on the OSL process in Al{sub 2}O{sub 3}:C.

  6. SU-E-I-57: Estimating the Occupational Eye Lens Dose in Interventional Radiology Using Active Personal Dosimeters Worn On the Chest

    Energy Technology Data Exchange (ETDEWEB)

    Omar, A; Marteinsdottir, M; Kadesjo, N; Fransson, A [Dept. of Medical Physics, Karolinska University Hospital, Stockholm (Sweden)

    2015-06-15

    Purpose: To provide a general formalism for determination of occupational eye lens dose based on the response of an active personal dosimeter (APD) worn at chest level above the radiation protection apron. Methods: The formalism consists of three factors: (1) APD conversion factor converting the reading at chest level (APDchest) to the corresponding personal dose equivalent at eye level, (2) Dose conversion factor transferring the measured dose quantity, Hp(10), into a dose quantity relevant for the eye lens dose, (3) Correction factor accounting for differences in exposure of the eye(s) compared to the exposure at chest level (e.g., due to protective lead glasses).The different factors were investigated and evaluated based on phantom and clinical measurements performed in an x-ray angiography suite for interventional cardiology. Results: The eye lens dose can be conservatively estimated by assigning an appropriate numerical value to each factor entering the formalism that in most circumstances overestimates the dose. Doing so, the eye lens dose to the primary operator and assisting staff was estimated in this work as D-eye,primary = 2.0 APDchest and D-eye,assisting = 1.0 APDchest, respectively.The annual eye lens dose to three nurses and one cardiologist was estimated to be 2, 2, 2, and 13 mSv (Hp(0.07)), respectively, using a TLD dosimeter worn at eye level. In comparison, using the formalism and APDchest measurements, the respective doses were 2, 2, 2, and 16 mSv (Hp(3)). Conclusion: The formalism outlined in this work can be used to estimate the occupational eye lens dose from the response of an APD worn on the chest. The formalism is general and could be applied also to other types of dosimeters. However, the numerical value of the different factors may differ from those obtained with the APD’s used in this work due to differences in dosimeter properties.

  7. Design and test of a scintillation dosimeter for dosimetry measurements of high energy radiotherapy beams; Conception et realisation d'un dosimetre a scintillation adapte a la dosimetrie de faisceaux de rayonnements ionisants en faisceaux de rayonnements ionisants en radiotherapie

    Energy Technology Data Exchange (ETDEWEB)

    Fontbonne, J.M

    2002-12-01

    This work describes the design and evaluation of the performances of a scintillation dosimeter developed for the dosimetry of radiation beams used in radiotherapy. The dosimeter consists in a small plastic scintillator producing light which is guided by means of a plastic optical fiber towards photodetectors. In addition to scintillation, high energy ionizing radiations produce Cerenkov light both in the scintillator and the optical fiber. Based on a wavelength analysis, we have developed a deconvolution technique to measure the scintillation light in the presence of Cerenkov light. We stress the advantages that are anticipated from plastic scintillator, in particular concerning tissue or water equivalence (mass stopping power, mass attenuation or mass energy absorption coefficients). We show that detectors based on this material have better characteristics than conventional dosimeters such as ionisation chambers or silicon detectors. The deconvolution technique is exposed, as well as the calibration procedure using an ionisation chamber. We have studied the uncertainty of our dosimeter. The electronics noise, the fiber transmission, the deconvolution technique and the calibration errors give an overall combined experimental uncertainty of about 0,5%. The absolute response of the dosimeter is studied by means of depth dose measurements. We show that absolute uncertainty with photons or electrons beams with energies ranging from 4 MeV to 25 MeV is less than {+-} 1 %. Last, at variance with other devices, our scintillation dosimeter does not need dose correction with depth. (author)

  8. Free-carrier contribution to the optical response of N-rich Cu{sub 3}N thin films

    Energy Technology Data Exchange (ETDEWEB)

    Gordillo, N; Agullo-Lopez, F [Centro de Microanalisis de Materiales, Universidad Autonoma de Madrid 28049-Madrid (Spain); Gonzalez-Arrabal, R [Instituto de Microelectronica de Madrid CSIC C/ Isaac Newton, 8. Tres Cantos, 28760-Madrid (Spain); Alvarez-Herrero, A, E-mail: nuria.gordillo@uam.e [Laboratorio de Instrumentacion Espacial, INTA, Torrejon de Ardoz, 28850-Madrid (Spain)

    2009-08-21

    The influence of nitrogen excess on the optical response of N-rich Cu{sub 3}N films is reported. The optical spectra measured in the wavelength range from 0.30 to 20.00 {mu}m have been correlated with the elemental film composition which can be adjusted in the nitrogen atomic percentage (at%) range from 27 {+-} 2 up to 33 {+-} 2. The absorption spectra for the N-rich films are consistent with direct optical transitions corresponding to the stoichiometric semiconductor Cu{sub 3}N plus a free-carrier contribution that can be tuned in accordance with the N-excess. The data are consistent with the incorporation of the excess N in the lattice as an electron acceptor that generates free holes.

  9. Gel dosimeters as useful dose and thermal-fluence detectors in Boron Neutron Capture Therapy (BNCT)

    Energy Technology Data Exchange (ETDEWEB)

    Gambarini, G.; Valente, M. [Department of Physics of the University and INFN, Via Celoria 16, I-20133 Milan (Italy); Moss, R.L.; Daquino, G.G.; Nievaart, V.A. [Joint Research Centre, Institute for Energy, P.O. Box 2, NL-1755ZG Petten, The Netherlands (Netherlands); Mariani, M.; Vanossi, E. [Department of Nuclear Engineering of Polytechnic, CESNEF, Via Ponzio, 34/3 - I-20133 Milan (Italy); Carrara, M. [Medical Physics Department, National Cancer Institute, Via Venezian 1, I-20131, Milan (Italy)

    2006-07-01

    The dosimetry method based on Fricke-Xylenol-Orange-infused gels in form of layers has shown noticeable potentiality for in-phantom or in-free-beam dose and thermal flux profiling and imaging in the high fluxes of thermal or epithermal neutrons utilised for boron neutron capture therapy (BNCT). Gel-dosimeters in form of layers give the possibility not only of obtaining spatial dose distributions but also of achieving measurements of each dose contribution in neutron fields. The discrimination of the various dose components is achieved by means of pixel-to-pixel manipulations of pairs of images obtained with gel-dosimeters having different isotopic composition. It is possible to place large dosimeters, detecting in such a way large dose images, because the layer geometry of dosimeters avoids sensitive variation of neutron transport due to the gel isotopic composition. Some results obtained after the last improvements of the method are reported. (Author)

  10. Dose verification to cochlea during gamma knife radiosurgery of acoustic schwannoma using MOSFET dosimeter

    Directory of Open Access Journals (Sweden)

    Sunil D Sharma

    2012-01-01

    Conclusion: The measured dose values were found in good agreement with the dose values calculated using the TPS. The MOSFET dosimeter can be a suitable choice for routine dose verification in the Gamma Knife radiosurgery.

  11. An intercomparison of neutron dosimeters and detectors for in-containment dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Auman, L.E.; Miller, W.H.; Graham, C.C.; Stretch, C.D.; Welty, T.J.; West, L. Jr. (Department of Nuclear Engineering, University of Missouri, Columbia (United States))

    1992-02-01

    To improve the methodology for assessing neutron dose at Union Electric's Callaway Nuclear Power Plant, an intercomparison of neutron detectors and dosimeters was performed. Seven different neutron detectors and dosimeters were tested in four different neutron fields utilizing facilities at the Missouri University Research Reactor and at the Southwest Radiation Calibration Center at the University of Arkansas. In general, all results agree within a factor of 2 in predicting the neutron dose equivalent. It was concluded that measurements of dose in containment should utilize the Tissue-Equivalent Proportional Counter (TEPC), the Bonner-sphere system, and the proton recoil spectrometer to accurately assess the neutron dose. These data can then be used to provide correction factors for more traditionally used dosimeters in containment, such as thermoluminescent dosimeters and survey meters.

  12. Voltage-Responsive Controlled Release Film with Cargo Release Self-Monitoring Property Based on Hydrophobicity Switching.

    Science.gov (United States)

    Jiao, Xiangyu; Li, Yanan; Li, Fengyu; Sun, Ruijuan; Wang, Wenqian; Wen, Yongqiang; Song, Yanlin; Zhang, Xueji

    2017-03-16

    Herein, voltage-responsive controlled release film was constructed by grafting ferrocene on the mesoporous inverse opal photonic crystal (mIOPC). The film achieved free-blockage controlled release and realized the monitoring of cargo release without external indicator. Free-blockage was attributed to the voltage switchable nanovalves which undergo hydrophobic-to-hydrophilic transition when applying voltage. Monitoring of cargo release was attributed to the optical property of mIOPC, the bandgap of mIOPC had a red shift when the solution invaded in. The film was hydrophobic enough to stop solution intrusion. Once the voltage was applied, the film became hydrophilic, leading to invasion of the solution. As a result, the cargos were released and the bandgap of mIOPC was red-shifted. Therefore, in this paper both a free-blockage controlled release film and a release sensing system was prepared. The study provides new insights into highly effective controlled release and release sensing without indicator.

  13. FlexyDos3D: a deformable anthropomorphic 3D radiation dosimeter: radiation properties

    DEFF Research Database (Denmark)

    De Deene, Yves; Skyt, Peter Sandegaard; Hill, Robin

    2015-01-01

    Three dimensional radiation dosimetry has received growing interest with the implementation of highly conformal radiotherapy treatments. The radiotherapy community faces new challenges with the commissioning of image guided and image gated radiotherapy treatments (IGRT) and deformable image...... and oxygen concentration has also been investigated. The radiophysical properties of this new dosimeter are discussed including stability, spatial integrity, temperature dependence of the dosimeter during radiation, readout and storage, dose rate dependence and tissue equivalence....

  14. Characterization of a water-equivalent fiber-optic coupled dosimeter for use in diagnostic radiology.

    Science.gov (United States)

    Hyer, Daniel E; Fisher, Ryan F; Hintenlang, David E

    2009-05-01

    This work reports on the characterization of a new fiber-optic coupled (FOC) dosimeter for use in the diagnostic radiology energy range. The FOC dosimeter was constructed by coupling a small cylindrical plastic scintillator, 500 microm in diameter and 2 mm in length, to a 2 m long optical fiber, which acts as a light guide to transmit scintillation photons from the sensitive element to a photo-multiplier tube (PMT). A serial port interface on the PMT permits real-time monitoring of light output from the dosimeter via a custom computer program. The FOC dosimeter offered excellent sensitivity and reproducibility, allowing doses as low as 0.16 mGy to be measured with a coefficient of variation of only 3.64%. Dose linearity was also excellent with a correlation coefficient of 1.000 over exposures ranging from 0.16 to 57.29 mGy. The FOC dosimeter exhibited little angular dependence from axial irradiation, varying by less than 5% over an entire revolution. A positive energy dependence was observed and measurements performed within a scatter medium yielded a 10% variation in sensitivity as beam quality changed due to hardening and scatter across a 16 cm depth range. The current dosimetry system features an array of five PMTs to allow multiple FOC dosimeters to be monitored simultaneously. Overall, the system allows for rapid and accurate dose measurements relevant to a range of diagnostic imaging applications.

  15. Compliance and data reliability in sun exposure studies with diaries and personal, electronic UV dosimeters.

    Science.gov (United States)

    Thieden, Elisabeth; Philipsen, Peter A; Wulf, Hans Christian

    2006-04-01

    Skin cancer risk estimations are based on sun exposure data. However, the reliability of collected data in personal ultraviolet (UV) dosimeters studies has not previously been validated. We aimed at investigating the data reliability and subject compliance in a study of sun exposure behaviour among 407 subjects (age range, 4-68 years) during 54 943 days based on time-stamped personal UV dosimeter readings and diary records. By comparing diary records and UV dosimeter readings on a daily basis, we investigated subject compliance, total sun exposure record, reasons for non-responding along with rates of diary completing errors. Efforts to improve compliance were described. The subject compliance rate was median 93.5% (percent days where the diary was completed and the UV dosimeter was worn). The total sun exposure record rate was median 84.1% (percent of participation days with both UV dosimeter and diary records and where the UV dosimeter was worn). Children, adolescents and golfers had lower sun exposure record rates than the rest of the groups (Pdosimeter maintenance service within 24 h and scrutinized data for errors and mistakes.

  16. UV dosimeter based on polyamide woven fabric and nitro blue tetrazolium chloride as an active compound

    Energy Technology Data Exchange (ETDEWEB)

    Kozicki, Marek, E-mail: mkozicki@mitr.p.lodz.pl [Institute of Architecture of Textiles, Technical University of Lodz, Zeromskiego 116, 90-924 Lodz (Poland); European Centre of Bio- and Nano-Technology (ECBNT), Technical University of Lodz, Zeromskiego 116, 90-924 Lodz (Poland); Sasiadek, Elzbieta [Institute of Architecture of Textiles, Technical University of Lodz, Zeromskiego 116, 90-924 Lodz (Poland); European Centre of Bio- and Nano-Technology (ECBNT), Technical University of Lodz, Zeromskiego 116, 90-924 Lodz (Poland)

    2011-10-15

    This paper reports on the preparation and features of a UV light dosimeter composed of nitro blue tetrazolium chloride (NBT) and polyamide woven fabric. This textile dosimeter is based on the conversion reaction of NBT into formazan, which was initially examined in aerated aqueous solutions through steady state UV irradiation. Irradiated solutions change their colour as a consequence of the formation of polydisperse NBT formazan particles. This was analysed in relation to the absorbed dose of UV light through UV-VIS spectrophotometry and dynamic laser light scattering measurements. When NBT substrate molecules are embedded in polyamide textile, UV irradiation leads to similar effects as in solution. However, the tinge intensity changes at much lower absorbed doses. The dependence of the tinge intensity on the absorbed dose was followed by measurements of the remission of light from the NBT-polyamide samples. Consequently, the calibration parameters were calculated such as the dose sensitivity, dose range, and quasi-linear dose range. An improvement of the NBT-polyamide samples by application of a colour levelling agent and improvement of their resistance to humidity is presented. Finally, the samples were used for estimation of absorbed UV energy distribution showing their capability as new dosimeters for in-plane high resolution radiation dose measurements. - Highlights: > Preparation of a textile dosimeter with nitro blue tetrazolium chloride is shown. > The dosimeter responds to UV light by a colour change. > 2D radiation dose measurements are possible. > PC scanners can be employed for measurements of the dosimeter.

  17. Fundamental study of nanoDot OSL dosimeters for entrance skin dose measurement in diagnostic x-ray examinations

    Energy Technology Data Exchange (ETDEWEB)

    Okazaki, Tohru; Kobayashi, Ikuo [Nagase Landauer, Ltd., Tsukuba (Japan); Hayashi, Hiroaki; Takegami, Kazuki; Okino, Hiroki; Kimoto, Natsumi; Maehata, Itsumi [Tokushima University, Tokushima (Japan)

    2016-09-15

    In order to manage the patient exposure dose in X-ray diagnosis, it is preferred to evaluate the entrance skin dose; although there are some evaluations about entrance skin dose, a small number of report has been published for direct measurement of patient. We think that a small-type optically stimulated luminescence (OSL) dosimeter, named nanoDot, can achieve a direct measurement. For evaluations, the corrections of angular and energy dependences play an important role. In this study, we aimed to evaluate the angular and the energy dependences of nanoDot. Materials and Methods We used commercially available X-ray diagnostic equipment. For angular dependence measurement, a relative response of every 15 degrees of nanoDot was measured in 40-140 kV X-ray. And for energy dependence measurement, mono-energetic characteristic X-rays were generated using several materials by irradiating the diagnostic X-rays, and the nanoDot was irradiated by the characteristic X-rays. We evaluated the measured response in an energy range of 8.1-75.5 keV. In addition, we performed Monte-Carlo simulation to compare experimental results. The experimental results were in good agreement with those of Monte-Carlo simulation. The angular dependence of nanoDot was almost steady with the response of 0 degrees except for 90 and 270 degrees. Furthermore, we found that difference of the response of nanoDot, where the nanoDot was irradiated from the randomly set directions, was estimated to be at most 5%. On the other hand, the response of nanoDot varies with the energy of incident X-rays; slightly increased to 20 keV and gradually decreased to 80 keV. These results are valuable to perform the precise evaluation of entrance skin dose with nanoDot in X-ray diagnosis. Conclusion The influence of angular dependence and energy dependence in X-ray diagnosis is not so large, and the nanoDot OSL dosimeter is considered to be suitable dosimeter for direct measurement of entrance surface dose of patient.

  18. Fast-response, sensitivitive and low-powered chemosensors by fusing nanostructured porous thin film and IDEs-microheater chip.

    Science.gov (United States)

    Dai, Zhengfei; Xu, Lei; Duan, Guotao; Li, Tie; Zhang, Hongwen; Li, Yue; Wang, Yi; Wang, Yuelin; Cai, Weiping

    2013-01-01

    The chemiresistive thin film gas sensors with fast response, high sensitivity, low power consumption and mass-produced potency, have been expected for practical application. It requires both sensitive materials, especially exquisite nanomaterials, and efficient substrate chip for heating and electrical addressing. However, it is challenging to achieve repeatable microstructures across the films and low power consumption of substrate chip. Here we presented a new sensor structure via the fusion of metal-oxide nanoporous films and micro-electro-mechanical systems (MEMS)-based sensing chip. An interdigital-electrodes (IDEs) and microheater integrated MEMS structure is designed and employed as substrate chip to in-situ fabricate colloidal monolayer template-induced metal-oxide (egg. SnO2) nanoporous sensing films. This fused sensor demonstrates mW-level low power, ultrafast response (~1 s), and parts-per-billion lever detection for ethanol gas. Due to the controllable template strategy and mass-production potential, such micro/nano fused high-performance gas sensors will be next-generation key miniaturized/integrated devices for advanced practical applications.

  19. Temperature-dependent stoichiometric alteration in ZnO:Mn nanostructured thin films for enhanced ferromagnetic response

    Science.gov (United States)

    Ilyas, Usman; Lee, P.; Tan, T. L.; Chen, R.; Anwar, Abdul Waheed; Zhang, Sam; Sun, H. D.; Rawat, R. S.

    2016-11-01

    The study investigates the effect of in-situ substrate temperature and argon-oxygen ambient gas pressure of pulsed laser deposition facility on material composition, optical quality and magnetic response of ZnO:Mn thin films. Structural and optical analyses revealed the existence of an optimal in-situ substrate temperature (450 °C) at which thin films showed relatively better texture and optical quality with minimum concentration of structural defects. The detailed analysis of Zn 2p3/2 and O 1s core level XPS spectra revealed that the structural disorder was considerably reduced in thin films after being annealed (in-situ) at substrate temperature of 450 °C. Magnetic measurements revealed the stronger p-d hybridization between oxygen 2p and Mn 3d orbitals in ZnO:Mn thin films being annealed in-situ at 450 °C under Ar:O2 admixture of 2.5 mbar subsequently leading to improved ferromagnetic response.

  20. Thin-film silica sol-gels doped with ion responsive fluorescent lipid bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, D.Y.; Shea, L.E.; Sinclair, M.B.

    1999-01-12

    A metal ion sensitive, fluorescent lipid-b i layer material (5oA PSIDA/DSPC) was successfully immobilized in a silica matrix using a tetramethoxysilane (TMOS) sol-gel procedure. The sol-gel immobilization method was quantitative in the entrapment of seif-assembled Iipid-bilayers and yielded thin films for facile configuration to optical fiber piatforms. The silica matrix was compatible with the solvent sensitive lipid bilayers and provided physical stabilization as well as biological protection. Immobilization in the silica sol-gel produced an added benefit of improving the bilayer's metal ion sensitivity by up to two orders of magnitude. This enhanced performance was attributed to a preconcentrator effect from the anionic surface of the silica matrix. Thin gels (193 micron thickness) were coupled to a bifurcated fiber optic bundle to produce a metal ion sensor probe. Response times of 10 - 15 minutes to 0.1 M CUCIZ were realized with complete regeneration of the sensor using an ethylenediarninetetraacetic acid (EDTA) solution.

  1. Kinetic Inductance Photodetectors Based on Nonequilibrium Response in Superconducting Thin-Film Structures

    Science.gov (United States)

    Sergeev, A. V.; Karasik, B. S.; Gogidze, I. G.; Mitin, V. V.

    2001-01-01

    While experimental studies of kinetic-inductance sensors have been limited so far by the temperature range near the superconducting transition, these detectors can be very sensitivity at temperatures well below the transition, where the number of equilibrium quasiparticles is exponentially small. In this regime, a shift of the quasiparticle chemical potential under radiation results in the change of the kinetic inductance, which can be measured by a sensitive SQUID readout. We modeled the kinetic inductance response of detectors made from disordered superconducting Nb, NbC, and MoRe films. Low phonon transparency of the interface between the superconductor and the substrate causes substantial re-trapping of phonons providing high quantum efficiency and the operating time of approximately 1 ms at 1 K. Due to the small number of quasiparticles, the noise equivalent power of the detector determined by the quasiparticle generation-recombination noise can be as small as approximately 10(exp -19) W/Hz(exp 1/2) at He4 temperatures.

  2. Co-sputtered metal and polymer nanocomposite films and their electrical responses for gas sensing application

    Science.gov (United States)

    Rujisamphan, Nopporn; Murray, Roy E.; Deng, Fei; Supasai, Thidarat

    2016-04-01

    Titanium and polytetrafluoroethylene (Ti-PTFE) nanocomposite thin films were successfully fabricated on glass substrates using a combination of dc and rf magnetron sputtering. When the Ti-PTFE composites were prepared at below the percolation threshold i.e. 27% metal volume filling (F), Ti clusters with the average sizes of 7 ± 2 nm were found. As the Ti content was increased above the percolation threshold (F = 62%), the connecting regions of Ti were formed within the polymer matrix and the electrical property changed rapidly from insulator-like to metal-like properties. The Ti-PTFE composites prepared near the percolation threshold showed the electrical response to different volatile organic compounds (VOCs). The sensitivity significantly depended upon the VOCs concentrations. These composites devices showed the presence of distinct chemical bonds of Csbnd C, Csbnd CF, Csbnd F and CF2 and TiF in TiO2 on the surface as investigated by X-ray photoelectron spectroscopy (XPS) while the surface morphology, characterized by atomic force microscopy (AFM) presented the root mean square (RMS) surface roughness of 13.3 nm. Cross-section transmission electron microscopy (TEM) images of the device revealed Ti clusters dispersed in PTFE matrix with particle sizes varied between 10 nm and 30 nm.

  3. Layer-by-Layer Assembly of a pH-Responsive and Electrochromic Thin Film

    Science.gov (United States)

    Schmidt, Daniel J.; Pridgen, Eric M.; Hammond, Paula T.; Love, J. Christopher

    2010-01-01

    This article summarizes an experiment on thin-film fabrication with layer-by-layer assembly that is appropriate for undergraduate laboratory courses. The purpose of this experiment is to teach students about self-assembly in the context of thin films and to expose students to the concepts of functional polymeric coatings. Students dip coat…

  4. Mechanical and Ferroelectric Response of Highly Textured PZT Films for Low Power MEMS

    Science.gov (United States)

    2012-10-01

    titanate films", Journal of Applied Physics , 89 (2), pp. 1336-1348, 2001. 4. Zavala, G., Fendler, J., Mckinstry, S. “Characterization of ferroelectric lead...zirconate titanate films by scanning force microscopy, Journal of Applied Physics , 81 (11), pp. 7480-7491, 1997. 5. Hidaka, T., et al

  5. Development of a wavelength-separated type scintillator with optical fiber (SOF) dosimeter to compensate for the Cerenkov radiation effect.

    Science.gov (United States)

    Ishikawa, Masayori; Nagase, Naomi; Matsuura, Taeko; Hiratsuka, Junichi; Suzuki, Ryusuke; Miyamoto, Naoki; Sutherland, Kenneth Lee; Fujita, Katsuhisa; Shirato, Hiroki

    2015-03-01

    The scintillator with optical fiber (SOF) dosimeter consists of a miniature scintillator mounted on the tip of an optical fiber. The scintillator of the current SOF dosimeter is a 1-mm diameter hemisphere. For a scintillation dosimeter coupled with an optical fiber, measurement accuracy is influenced by signals due to Cerenkov radiation in the optical fiber. We have implemented a spectral filtering technique for compensating for the Cerenkov radiation effect specifically for our plastic scintillator-based dosimeter, using a wavelength-separated counting method. A dichroic mirror was used for separating input light signals. Individual signal counting was performed for high- and low-wavelength light signals. To confirm the accuracy, measurements with various amounts of Cerenkov radiation were performed by changing the incident direction while keeping the Ir-192 source-to-dosimeter distance constant, resulting in a fluctuation of Optical fiber bending was also addressed; no bending effect was observed for our wavelength-separated SOF dosimeter.

  6. Thin film synthesis of SbSI micro-crystals for self-powered photodetectors with rapid time response.

    Science.gov (United States)

    Gödel, Karl C; Steiner, Ullrich

    2016-09-21

    We describe a new thin film deposition method for the growth of crystalline SbSI micro-needles via the conversion of Sb2S3 using SbI3 vapour, in a facile process that takes less than 15 minutes. These films were used to construct photodetectors in a sandwich-type architecture, which are superior to previously reported SbSI photodetectors. The devices exhibit a detectivity of D* = 10(9) Jones, a signal-to-noise ratio greater than SNR = 10(3) and a responsivity of R = 10(-5) A W(-1). In time response measurements, raise and fall times of less than 8 ms and 34 ms were determined. This manufacturing method greatly simplifies the creation of fast photodetectors.

  7. Production of LiF films for dosimetric thermoluminescence application; Producao de filmes de LiF para aplicacao em dosimetria termoluminescente

    Energy Technology Data Exchange (ETDEWEB)

    Mauricio, Claudia Lucia de Pinho

    2000-12-01

    This work studies the LiF monolayer and multilayer polycrystalline film's dosimetric properties. The films were produced by electron beam evaporation technique in aluminium and stainless steel substrates maintained at several temperatures. As dosimetric variable, the intensity of the thermoluminescent (TL) glow curve of the films was used. effects of the substrate type and temperature; of the addition of layers of Mg F{sub 2} NaF and Cu F{sub 2} to the LiF films; and of thermal treatments in the TL response of the produced films were studied. The microstructural characterization of the films was accomplished through measures of scanning electronic microscopy and grazing incidence X-rays diffraction analysis. The dosimetric characterization was made of gamma radiation exposure in a {sup 60} Co source, with kerma from 0,1 to 500 Gy. Studies of reproducibility, homogeneity, stability and other environmental effects were also made. LiF and Cu F{sub 2}: LiF; Mg F{sub 2} films were the only ones that presented mechanical stability and reproducibility of the TL emission. There is a strong indication of some correlation between the residual tension fields inside the films and the intensity of its TL emission peaks. LiF monolayer films present supralinear behaviour from 0,2 to 100 Gy. These films present a main TL glow peak around 150 deg C, whose half-time is about 30 days. Its volumetric sensitivity can reach about 60 times that of LiF powder and about 0,25 that of TLD100 (LiF:Mg, Ti commercial dosimeter from Harshaw Chemical Co.) The homogeneity and reproducibility inside a same film batch is better than 12% for 95% confidence level. Cu F{sub 2} : LiF: Mg F{sub 2} films present linear behaviour from 3 to 500 Gy and its main TL glow peak around 200 deg C did not present any fading for a a period of 30 days, in laboratory conditions. This glow peak is characteristic of the Mg doping of LiF, which confirms the diffusion of Mg ions from the Mg F{sub 2} layer to the Li

  8. A novel method for alpha dosimetry using peeled-off Gafchromic EBT3 films

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwang-Ho; Kim, Eun-Hee [Seoul National University, Seoul (Korea, Republic of)

    2016-10-15

    One can estimate dose imposed to film by measuring the optical density of film. EBT3 film has been used in dose measurement for photon, proton, and electron beams but not for alpha particles. Both sides of diacetylene monomer layer are covered with 100 μm-thick polyester coating layers, through which alpha particles even at several MeV cannot penetrate. A recent study demonstrated the use of EBT3 film in alpha dosimetry by peeling off one side of polyester coating layer. Their study did not inform the reliability of measurement using the peeled-off films. In this study, we evaluated the feasibility of EBT3 film as a substitute for conventional alpha dosimeters and checked the uncertainty of dose measurements obtained with peeled-off EBT3 films. We also applied this film dosimeter to measuring of the fluence distribution at cell targets in a culture dish set in the alpha irradiation chamber of the Radiation Bioengineering Laboratory (RadBio Lab) at Seoul National University (SNU). In this work, we confirmed the feasibility of using Gafchromic EBT3 films for alpha dosimetry. The peeled-off EBT3 films can make a convenient alpha dosimeter by carrying an uncertainty less than 9 %.

  9. Visible light responsive photocatalytic ZnO:Al films decorated with Ag nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bizarro, M., E-mail: monserrat@iim.unam.mx; Martínez-Padilla, E.

    2014-02-28

    The spray pyrolysis technique was used to grow ZnO:Al films decorated with silver nanoparticles in their surface, in order to increase and stabilize the photocatalytic activity of ZnO. The appropriate amount of Ag nanoparticles was determined varying the concentration of an AgNO{sub 3} solution and the spraying time. The films were characterized by X-ray diffraction, scanning electron microscopy and energy dispersed spectroscopy. The photocatalytic activity of the films was evaluated by the degradation of a methyl orange dye solution. The stability of the photocatalytic activity was studied along five degradation cycles while exposed to simulated sunlight, white light and UV light. We found that a spraying time of 8 min of the AgNO{sub 3} solution gives nearly 3 at% of Ag in the ZnO:Al films. This amount of Ag nanoparticles stabilized the photoactivity under UV and sunlight along five degradation cycles, showing a synergistic effect between Al and Ag that greatly improved the photocatalytic performance of ZnO films. - Highlights: • ZnO:Al/Ag films were produced in a two step process by spray pyrolysis. • ZnO:Al/Ag films presented a high photocatalytic activity under visible light. • Ag nanoparticles stabilized the photocatalytic efficiency after several reuses. • Al and Ag impurities gave a synergistic effect that improved ZnO photocatalytic performance.

  10. The application of polymer gel dosimeters to dosimetry for targeted radionuclide therapy

    Energy Technology Data Exchange (ETDEWEB)

    Gear, J I [Joint Department of Physics, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, Surrey (United Kingdom); Flux, G D [Joint Department of Physics, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, Surrey (United Kingdom); Charles-Edwards, E [Clinical Magnetic Research Group, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, Surrey (United Kingdom); Partridge, M [Joint Department of Physics, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, Surrey (United Kingdom); Cook, G [Department of Nuclear Medicine, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, Surrey (United Kingdom); Ott, R J [Joint Department of Physics, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, Surrey (United Kingdom)

    2006-07-21

    There is a lack of standardized methodology to perform dose calculations for targeted radionuclide therapy and at present no method exists to objectively evaluate the various approaches employed. The aim of the work described here was to investigate the practicality and accuracy of calibrating polymer gel dosimeters such that dose measurements resulting from complex activity distributions can be verified. Twelve vials of the polymer gel dosimeter, 'MAGIC', were uniformly mixed with varying concentrations of P-32 such that absorbed doses ranged from 0 to 30 Gy after a period of 360 h before being imaged on a magnetic resonance scanner. In addition, nine vials were prepared and irradiated using an external 6 MV x-ray beam. Magnetic resonance transverse relaxation time, T{sub 2}, maps were obtained using a multi-echo spin echo sequence and converted to R{sub 2} maps (where T{sub 2} = 1/R{sub 2}). Absorbed doses for P-32 irradiated gel were calculated according to the medical internal radiation dose schema using EGSnrc Monte Carlo simulations. Here the energy deposited in cylinders representing the irradiated vials was scored. A relationship between dose and R{sub 2} was determined. Effects from oxygen contamination were present in the internally irradiated vials. An increase in O{sub 2} sensitivity over those gels irradiated externally was thought to be a result of the longer irradiation period. However, below the region of contamination dose response appeared homogenous. Due do a drop-off of dose at the periphery of the internally irradiated vials, magnetic resonance ringing artefacts were observed. The ringing did not greatly affect the accuracy of calibration, which was comparable for both methods. The largest errors in calculated dose originated from the initial activity measurements, and were approximately 10%. Measured R{sub 2} values ranged from 5-35 s{sup -1} with an average standard deviation of 1%. A clear relationship between R{sub 2} and dose was

  11. Radiochromic dye dosimeter solutions as reference measurement systems

    Science.gov (United States)

    Farahani, Mahnaz; McLaughlin, William L.

    Solutions of leucocyanides of triphenylmethane dyes in organic solvents are designed as stable reference dosimeters for large radiation doses, with useful characteristics, both for steady-state and pulsed radiation fields. These radiochromic solutions may be used in conventional glass ampoules to cover the absorbed dose range 10 2-10 4kGy, when analyzed spectrophotometrically at visible wavelengths at the maxima of radiation-induced absorption bands. The radiation chemical yields of dye formation ( G-values) and molar linear absorption coefficients (ɛ m) of the dyes in several formulations, with and without dissolved polymer and weak oxidizing agents, are established. The most stable formulation before and after irradiation consists of new fuchsin cyanide in a mixture of dimethyl sulfoxide and triethyl phosphate containing small amounts of acetic acid, p-nitrobenzoic acid and polyvinyl butyral. The useful range of doses for this solution is 10 2-4 x 10 3 Gy when measured at 557 nm wavelength. The radiation chemical yield, G-value for dye production, is 3.35 x 10 15 molec J -1 (0.0055 μmol J -1) and the value of ɛ m at this wavelength is 1.32 x 10 5 M -1 cm -1.

  12. Quality control for X-ray dosimetry with Fricke dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Vivianne Lucia Bormann de [Centro Regional de Cincias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil)]. E-mail: lsouza@cnen.gov.br; Austerlitz, C. [East Carolina University, NC (United States)]. E-mail: camposc@ecu.edu

    2007-07-01

    It is a well-established fact that the success of radiation therapy is dependent on the accurate dosimetry of the radiation beam used. This dosimetry must include equipment performance as well. A system for Fricke dosimetry was used for this purpose. The Fricke solution and a parallel ionization chamber (used for comparison) were irradiated with an X-ray beam from a Pantak X-ray equipment. The ionization chamber was positioned at a distance of 500 mm of the focal point, in the central axis of the X-ray field which is defined as 100x100 mm{sup 2} at the calibration distance. A plexiglas phantom appropriate to hold the polypropylene tube was used to irradiate the vials with the Fricke solution. The irradiated solutions were transferred directly from the polypropylene vials to 10 mm length cuvettes and the optical densities were measured in 304 nm using a Beckman Counter Model DU 640 spectrophotometer. Three institutions were visited to verify their procedures and two were in accordance with the lAEA recommended procedures for soft X-ray dosimetry. The results of the measurements performed in the institutions visited show that the Fricke dosimeter system developed can be used for quality control for soft X-ray equipment. (author)

  13. Impact of stoichiometry on the linear and nonlinear optical response of SnOx thin films

    Science.gov (United States)

    Li, Zhong-guo; Liang, Ling-yan; Cao, Hong-tao; Song, Ying-lin

    2017-06-01

    SnO is a promising p-type oxide semiconductor materials for applications such as transparent electronics and solar cells. However, further improvement of its performance is hindered by its diverse stoichiometry. We investigated the nonlinear and saturable absorption characteristics of pristine SnO and O-rich SnOx films by femtosecond degenerate pump-probe measurements at 515 nm. UV-Vis absorption data indicate bandgap blueshift with increasing oxygen concentration. Pristine SnO film exhibit saturable absorption while nonlinear absorption is observed in O-rich SnOx films. Our results shed light on the utilization of SnO in future device applications.

  14. MO-F-CAMPUS-T-04: Utilization of Optical Dosimeter for Modulated Spot-Scanning Particle Beam

    Energy Technology Data Exchange (ETDEWEB)

    Hsi, W; Li, Y; Huang, Z; Sheng, Y; Deng, Y; Zhao, J; Zhao, F; Sun, L; Moyers, M [Shanghai Proton and Heavy Ion Center, Pudong, Shangai (China)

    2015-06-15

    Purpose: To present the utilization of an optical dosimeter for modulated spot-scanning carbon-ion and proton beams during the acceptance test of Siemens IONTRIS system. Method and Materials: An optical dosimeter using phosphor scintillation was developed to map and interactively analyze the shapes and sizes of spots over 190 energies for ProTom modulated-scanning system. The dose response to proton had been characterized with proper pixel calibration at ProTom system. The dose response was further studied at 0.7 cm depths by uniform 8cm in-diameter fields of 424.89 MeV/u (E290) carbon-ions and 215.18MeV (E282) protons at IONTRIS system. The virtual source axial distances (vSAD) of carbonions and protons of IONTRIS system was investigated by measuring either variations of spot position or field size at five different locations to Isocenter. By measuring lateral profiles of uniform doses with varied thin-thicknesses of chest-board pattern and placing the scintillation plate at near to the distal edge, range variations at different off-axis-distances (rOAD) were examined. Relative accuracy and reproducibility of beam range were measured for three beam ranges with a ramping block at front of scintillation plate. Results: Similar dose response was observed for high energies of carbon ions and protons. Mean vSAD at X and Y axes were 744.1 cm and 807.4cm with deviation of 7.4cm and 7.7cm, respectively. Variation of rOAD was within 0.35 mm over 10cm for both protons and carbon ions. Accuracy of measuring relative distal range using the ramping block was 0.2mm. Measured range over repeated three times for each range were within 0.25mm at same room, and within 1.0mm between four rooms. Conclusions: The optical dosimeter could efficiently measure the virtual source distance. And, to measure small range variation at different off-axial locations, and for the relative beam range between rooms during acceptance test of a modulated spot-scanning particle system.

  15. SU-E-T-368: Effect of a Strong Magnetic Field On Select Radiation Dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Mathis, M; Wen, Z; Tailor, R; Sawakuchi, G; Flint, D; Beddar, S; Ibbott, G [The University of Texas MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-01

    Purpose: To determine the effect of a strong magnetic field on TLD-100, OSLD (Al{sub 2}O{sub 2}:C), and PRESAGE dosimetry devices. This study will help to determine which types of dosimeters can be used for quality assurance and in-vivo dosimetry measurements in a magnetic resonance imaginglinear accelerator (MRI-linac) system. Methods: The dosimeters were separated into two categories which were either exposed or not exposed to a strong magnetic field. In each category a set of dosimeters was irradiated with 0, 2, or 6 Gy. To expose the dosimeters to a magnetic field the samples in that category were place in a Bruker small animal magnetic resonance scanner at a field strength slightly greater than 2.5 T for at least 1 hour preirradiation and at least 1 hour post-irradiation. Irradiations were performed with a 6 MV x-ray beam from a Varian TrueBeam linac with 10×10 cm{sup 2} field at a 600 MU/min dose rate. The samples that received no radiation dose were used as control detectors. Results: The readouts of the dosimeters which were not exposed to a strong magnetic field were compared with the measurements of the dosimetry devices which were exposed to a magnetic field. No significant differences (less than 2% difference) in the performance of TLD, OSLD, or PRESAGE dosimeters due to exposure to a strong magnetic field were observed. Conclusion: Exposure to a strong magnetic field before and after irradiation does not appear to change the dosimetric properties of TLD, OSLD, or PRESAGE which indicates that these dosimeters have potential for use in quality assurance and in-vivo dosimetry in a MRI-linac. We plan to further test the effect of magnetic fields on these devices by irradiating them in the presence of a magnetic fields similar to those produced by a MRI-linac system. Elekta-MD Anderson Cancer Center Research Agreement.

  16. Study of a non-diffusing radiochromic gel dosimeter for 3D radiation dose imaging

    Science.gov (United States)

    Marsden, Craig Michael

    2000-12-01

    This thesis investigates the potential of a new radiation gel dosimeter, based on nitro-blue tetrazolium (NBTZ) suspended in a gelatin mold. Unlike all Fricke based gel dosimeters this dosimeter does not suffer from diffusive loss of image stability. Images are obtained by an optical tomography method. Nitro blue tetrazolium is a common biological indicator that when irradiated in an aqueous medium undergoes reduction to a highly colored formazan, which has an absorbance maximum at 525nm. Tetrazolium is water soluble while the formazan product is insoluble. The formazan product sticks to the gelatin matrix and the dose image is maintained for three months. Methods to maximize the sensitivity of the system were evaluated. It was found that a chemical detergent, Triton X-100, in combination with sodium formate, increased the dosimeter sensitivity significantly. An initial G-value of formazan production for a dosimeter composed of 1mM NBTZ, gelatin, and water was on the order of 0.2. The addition of Triton and formate produced a G-value in excess of 5.0. The effects of NBTZ, triton, formate, and gel concentration were all investigated. All the gels provided linear dose vs. absorbance plots for doses from 0 to >100 Gy. It was determined that gel concentration had minimal if any effect on sensitivity. Sensitivity increased slightly with increasing NBTZ concentration. Triton and formate individually and together provided moderate to large increases in dosimeter sensitivity. The dosimeter described in this work can provide stable 3D radiation dose images for all modalities of radiation therapy equipment. Methods to increase sensitivity are developed and discussed.

  17. Taurine-EVA copolymer-paraffin rods dosimeters for EPR high-dose radiation dosimetry

    Directory of Open Access Journals (Sweden)

    Maghraby Ahmed M.

    2014-03-01

    Full Text Available Taurine/EPR rods (3 × 10 mm have been prepared by a simple technique in the laboratory where taurine powder was mixed with a molten mixture of paraffin wax and an ethylene vinyl acetate (EVA copolymer. The binding mixture EVA/Paraffin does not present interference or noise in the EPR signal before or after irradiation. The rods show good mechanical properties for safe and multi-use handling. An EPR investigation of radiation induced radicals in taurine rods revealed that there are two types of radicals produced after exposure to gamma radiation (60Co. EPR spectra were recorded and analyzed - also the microwave power saturation and modulation amplitude were studied and optimized. Response of taurine to different radiation doses (1.5-100 kGy was studied and found to follow a linear relationship up to 100 kGy. Radiation induced radicals in taurine persists and showed a noticeable stability over 94 days following irradiation. Uncertainities associated with the evaluation of radiation doses using taurine dosimeters were discussed and tabulated. It was found that taurine possesses good dosimetric properties using EPR spectroscopy in high doses in addition to its simple spectrum.

  18. 3D dose distribution measurements in brachytherapy using radiochromic gel dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Solc, J., E-mail: jsolc@cmi.c [Czech Metrology Institute-Inspectorate for Ionizing Radiation, Radiova 1, CZ 102 00 Prague 10 (Czech Republic); Sochor, V.; Kacur, M.; Smoldasova, J. [Czech Metrology Institute-Inspectorate for Ionizing Radiation, Radiova 1, CZ 102 00 Prague 10 (Czech Republic)

    2010-07-21

    The paper informs about the joint research project 'Increasing cancer treatment efficacy using 3D brachytherapy' which is a three-year project carried out in cooperation with European national metrology institutes and co-funded by the European Community's Seventh Framework Program for research and technological development. The goal of the project is to improve the measurement and standardization of dose-to-water rate by brachytherapy (BT) sources. The paper gives a summary of the individual parts of the whole project and describes in more detail the task of the Czech Metrology Institute: the determination of spatial distribution of dose-to-water by BT sources using radiochromic gel dosimeters, including a new gel with suppressed diffusion. The response of irradiated gels is evaluated using the optical cone beam computed tomography (CT) technique. The characteristics of the optical CT scanner are discussed with respect to CCD camera performance and light source. The optimized composition of the new gel and its dosimetric properties are highlighted. The results show that the radiochromic gels are convenient for measuring the 3D distribution of dose-to-water and could be an alternative to current methods of dose distribution measurements.

  19. 3D dose distribution measurements in brachytherapy using radiochromic gel dosimeters

    Science.gov (United States)

    Šolc, J.; Sochor, V.; Kačur, M.; Šmoldasová, J.

    2010-07-01

    The paper informs about the joint research project "Increasing cancer treatment efficacy using 3D brachytherapy" which is a three-year project carried out in cooperation with European national metrology institutes and co-funded by the European Community's Seventh Framework Program for research and technological development. The goal of the project is to improve the measurement and standardization of dose-to-water rate by brachytherapy (BT) sources. The paper gives a summary of the individual parts of the whole project and describes in more detail the task of the Czech Metrology Institute: the determination of spatial distribution of dose-to-water by BT sources using radiochromic gel dosimeters, including a new gel with suppressed diffusion. The response of irradiated gels is evaluated using the optical cone beam computed tomography (CT) technique. The characteristics of the optical CT scanner are discussed with respect to CCD camera performance and light source. The optimized composition of the new gel and its dosimetric properties are highlighted. The results show that the radiochromic gels are convenient for measuring the 3D distribution of dose-to-water and could be an alternative to current methods of dose distribution measurements.

  20. Dedicated multichannel readout ASIC coupled with single crystal diamond for dosimeter application

    Science.gov (United States)

    Fabbri, A.; Falco, M. D.; De Notaristefani, F.; Galasso, M.; Marinelli, M.; Orsolini Cencelli, V.; Tortora, L.; Verona, C.; Verona Rinati, G.

    2013-02-01

    This paper reports on the tests of a low-noise, multi-channel readout integrated circuit used as a readout electronic front-end for a diamond multi-pixel dosimeter. The system is developed for dose distribution measurement in radiotherapy applications. The first 10-channel prototype chip was designed and fabricated in a 0.18 um CMOS process. Every channel includes a charge integrator with a 10 pF capacitor and a double slope A/D converter. The diamond multi-pixel detector, based on CVD synthetic single crystal diamond Schottky diodes, is made by a 3 × 3 sensor matrix. The overall device has been tested under irradiation with 6 MeV radio therapeutic photon beams at the Policlinico ``Tor Vergata'' (PTV) hospital. Measurements show a 20 fA RMS leakage current from the front-end input stage and a negligible dark current from the diamond detector, a stable temporal response and a good linear behaviour as a function of both dose and dose rate. These characteristics were common to each tested channel.

  1. Preliminary results on TL and OSL aluminium oxide dosimeters developed at IPEN

    Energy Technology Data Exchange (ETDEWEB)

    Fukumori, David T.; Yoshito, Walter K.; Ussui, Valter; Lazar, Dolores R.R.; Campos, Leticia L., E-mail: fukumori@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    The aluminum oxide composes the modern TL and OSL radiation dosimeters. TL and OSL phenomena are related to chemical elements in the crystalline structure of {alpha}-Al{sub 2}O{sub 3}. The aim of this work was to develop materials based on aluminum oxide for use in TL and OSL dosimetry. The studies included the dosimetric properties of alumina samples obtained by electro fusion, adsorption and coprecipitation. Electro fused alumina commercially available as abrasive particles was used to produce the pellets by glass sintering. Adsorption and coprecipitation were the methods used to insert metal ions to alumina. The best results were achieved with electro fused alumina and Tm{sup 3+} doped Al{sub 2}O{sub 3} pellets. The electro fused alumina-glass pellets show TL and OSL signals and the TL curve has two peaks. Its minimum detectable radiation dose is 7.2 mGy and the linearity of TL response as function of dose is up to about 800 mGy. The {alpha}-Al{sub 2}O{sub 3}:Tm pellets produced by sintering at 1550 deg C presented a meaningful TL glow curve so that it is worth studying their properties and viability of use in dosimetry. (author)

  2. Process optimization of deposition conditions of PbS thin films grown by a successive ionic layer adsorption and reaction (SILAR) method using response surface methodology

    Science.gov (United States)

    Yücel, Ersin; Yücel, Yasin; Beleli, Buse

    2015-07-01

    In this study, lead sulfide (PbS) thin films were synthesized by a successive ionic layer adsorption and reaction (SILAR) method with different pH, dipping time and dipping cycles. Response surface methodology (RSM) and central composite design (CCD) were successfully used to optimize the PbS films deposition parameters and understand the significance and interaction of the factors affecting the film quality. 5-level-3-factor central composite design was employed to evaluate the effects of the deposition parameters (pH, dipping time and dipping cycles) on the response (the optical band gap of the films). Data obtained from RSM were subjected to the analysis of variance (ANOVA) and analyzed using a second order polynomial equation. The optimal conditions for the PbS films deposition have been found to be: pH of 9.1, dipping time of 10 s and dipping cycles of 10 cycles. The predicted band gap of PbS film was 2.13 eV under the optimal conditions. Verification experiment (2.24 eV) confirmed the validity of the predicted model. The film structures were characterized by X-ray diffractometer (XRD). Morphological properties of the films were studied with a scanning electron microscopy (SEM). The optical properties of the films were investigated using a UV-visible spectrophotometer.

  3. Synthesis and biological response of casein-based silica nano-composite film for drug delivery system.

    Science.gov (United States)

    Ma, Jianzhong; Xu, Qunna; Zhou, Jianhua; Zhang, Jing; Zhang, Limin; Tang, Huiru; Chen, Lihong

    2013-11-01

    Casein possesses many interesting properties that make it a good candidate for conventional and novel drug delivery systems. In this study, casein-based silica nano-composite was prepared via double in situ method, and the as-prepared latex particles were evaluated in terms of their morphology and size through transmission electron microscopy (TEM). The film morphology was investigated by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX), and the mechanical property and response behavior of the films as a function of silica content were discussed. Ibuprofen was used as the model drug. The drug load and release properties were studied by solid-state nuclear magnetic resonance (solid-state NMR), Fourier transform infrared (FT-IR), SEM and in vitro test. The composite latex particle showed a stable core-shell structure, and the film exhibited a regular surface with even SiO2 distribution. The drug load efficiency of the composite films increased with adding silica because of the adsorption of the drugs on the silica. In an acidic release medium, the ibuprofen-loaded composite showed a slower drug release dependent on the silica content. These behaviors were most likely due to the reduced diffusion rate of the drug through the composite microsphere, which resulted from the interaction between the silica and the drug.

  4. Ultrafast lattice response of photoexcited thin films studied by X-ray diffraction

    Directory of Open Access Journals (Sweden)

    Daniel Schick

    2014-11-01

    Full Text Available Using ultrafast X-ray diffraction, we study the coherent picosecond lattice dynamics of photoexcited thin films in the two limiting cases, where the photoinduced stress profile decays on a length scale larger and smaller than the film thickness. We solve a unifying analytical model of the strain propagation for acoustic impedance-matched opaque films on a semi-infinite transparent substrate, showing that the lattice dynamics essentially depend on two parameters: One for the spatial profile and one for the amplitude of the strain. We illustrate the results by comparison with high-quality ultrafast X-ray diffraction data of SrRuO3 films on SrTiO3 substrates.

  5. Enhanced high temperature thermoelectric response of sulphuric acid treated conducting polymer thin films

    KAUST Repository

    Sarath Kumar, S. R.

    2015-11-24

    We report the high temperature thermoelectric properties of solution processed pristine and sulphuric acid treated poly(3, 4-ethylenedioxythiophene):poly(4-styrenesulfonate) (or PEDOT:PSS) films. The acid treatment is shown to simultaneously enhance the electrical conductivity and Seebeck coefficient of the metal-like films, resulting in a five-fold increase in thermoelectric power factor (0.052 W/m. K ) at 460 K, compared to the pristine film. By using atomic force micrographs, Raman and impedance spectra and using a series heterogeneous model for electrical conductivity, we demonstrate that acid treatment results in the removal of PSS from the films, leading to the quenching of accumulated charge-induced energy barriers that prevent hopping conduction. The continuous removal of PSS with duration of acid treatment also alters the local band structure of PEDOT:PSS, resulting in simultaneous enhancement in Seebeck coefficient.

  6. Calcium phosphate thin films enhance the response of human mesenchymal stem cells to nanostructured titanium surfaces

    Directory of Open Access Journals (Sweden)

    Mura M McCafferty

    2014-05-01

    Full Text Available The development of biomaterial surfaces possessing the topographical cues that can promote mesenchymal stem cell recruitment and, in particular, those capable of subsequently directing osteogenic differentiation is of increasing importance for the advancement of tissue engineering. While it is accepted that it is the interaction with specific nanoscale topography that induces mesenchymal stem cell differentiation, the potential for an attendant bioactive chemistry working in tandem with such nanoscale features to enhance this effect has not been considered to any great extent. This article presents a study of mesenchymal stem cell response to conformal bioactive calcium phosphate thin films sputter deposited onto a polycrystalline titanium nanostructured surface with proven capability to directly induce osteogenic differentiation in human bone marrow–derived mesenchymal stem cells. The sputter deposited surfaces supported high levels of human bone marrow–derived mesenchymal stem cell adherence and proliferation, as determined by DNA quantification. Furthermore, they were also found to be capable of directly promoting significant levels of osteogenic differentiation. Specifically, alkaline phosphatase activity, gene expression and immunocytochemical localisation of key osteogenic markers revealed that the nanostructured titanium surfaces and the bioactive calcium phosphate coatings could direct the differentiation towards an osteogenic lineage. Moreover, the addition of the calcium phosphate chemistry to the topographical profile of the titanium was found to induce increased human bone marrow–derived mesenchymal stem cell differentiation compared to that observed for either the titanium or calcium phosphate coating without an underlying nanostructure. Hence, the results presented here highlight that a clear benefit can be achieved from a surface engineering strategy that combines a defined surface topography with an attendant, conformal

  7. Predictors of men's sexual response to erotic film stimuli: the role of affect and self-reported thoughts.

    Science.gov (United States)

    Oliveira, Cátia; Laja, Pedro; Carvalho, Joana; Quinta Gomes, Ana; Vilarinho, Sandra; Janssen, Erick; Nobre, Pedro J

    2014-11-01

    Both emotions and cognitions seem to play a role in determining sexual arousal. However, no studies to date have tested the effects of self-reported thoughts on subjective sexual arousal and genital response using psychophysiological methods. The aim of the present study was to evaluate the role of self-reported thoughts and affect during exposure to erotic material in predicting subjective and genital responses in sexually healthy men. Twenty-seven men were presented with two explicit films, and genital responses, subjective sexual arousal, self-reported thoughts, and positive and negative affect were assessed. Men's genital responses, subjective sexual arousal, affective responses, and self-reported thoughts during exposure to sexual stimulus were measured. Regression analyses revealed that genital responses were predicted by self-reported thoughts (explaining 20% of the variance) but not by affect during exposure to erotic films. On the other hand, subjective sexual arousal was significantly predicted by both positive and negative affect (explaining 18% of the variance) and self-reported thoughts (explaining 37% of the variance). Follow-up analyses using the single predictors showed that "sexual arousal thoughts" were the only significant predictor of subjective response (β = 0.64; P < 0.01) and that "distracting/disengaging thoughts" were the best predictor of genital response (β = -0.51; P < 0.05). The findings of this study suggest that both affect and sexual arousal thoughts play an important role in men's subjective sexual response, whereas genital response seems to be better predicted by distracting thoughts. © 2014 International Society for Sexual Medicine.

  8. Photocatalytic Activity of Vis-Responsive Ag-Nanoparticles/TiO2 Composite Thin Films Fabricated by Molecular Precursor Method (MPM

    Directory of Open Access Journals (Sweden)

    Mitsunobu Sato

    2013-07-01

    Full Text Available The Ag-nanoparticles (Ag-NP/TiO2 composite thin films with various amounts of Ag (10 mol% ≤ n ≤ 80 mol% were examined as a potential photocatalyst by decoloration reaction of methylene blue (MB in an aqueous solution. These composite thin films of ca. 100 nm thickness were fabricated by the MPM at 600 °C in air. The decoloration rates monitored by the absorption intensity of the MB solution indicated that the composite thin films of Ag with an amount less than 40 mol% are not effective under vis-irradiation, though they can work as a photocatalyst under UV-irradiation. Further, the UV-sensitivity of the composite thin films gradually decreased to almost half the level of that of the TiO2 thin film fabricated under the identical conditions when the Ag amount increased from 10 to 40 mol%. Contrarily, the composite thin films of Ag content larger than 50 mol% showed the vis-responsive activity, whose level was slightly lower than the decreased UV-sensitivity. Diffuse reflectance spectra suggested that the vis-responsive activity of the composite thin films is due to the conductivity, localized surface plasmon resonance and surface plasmon resonance of Ag-NP. It was also elucidated that the vis-responsive level of the composite thin films corresponds to their electrical conductivity that depends on the Ag content.

  9. Effect of Mixed Solvents Consisting of Water and Organic Solvent on Preparation of Medium-Responsive Grafted Cellulose Film by Means of Photografting

    Directory of Open Access Journals (Sweden)

    Irwan Ginting-Suka

    2006-11-01

    Full Text Available Cellulose having a medium-responsive function were synthesized by photografting of methacrylic acid (MAA on regenerated cellulose film (thickness = 20 µm at 60°C using mixed solvent consisting of water and organic solvents such as acetone and methanol. Xanthone was used as photoinitiator by coating on the film surfaces. A maximum percentage of grafting was observed at a certain concentration of organic solvent. MAA-grafted cellulose films produced showing homogeneous distribution of grafted chains, which was examined by scanning electron microscopy. The modified films also exhibit medium responsive character, it shrinks in acidic and swells in basic solution. Moreover, the grafted film exhibited the ability to absorb copper ion, which was not influenced by the solvent used in grafting processes.

  10. Single and multichannel scintillating fiber dosimeter for radiotherapic beams with SiPM readout

    Science.gov (United States)

    Berra, A.; Ferri, A.; Novati, C.; Ostinelli, A.; Paternoster, G.; Piemonte, C.; Prest, M.; Vallazza, E.

    2016-12-01

    The treatment of many neoplastic diseases requires the use of radiotherapy, which consists in the irradiation of the tumor, identified as the target volume, with ionizing radiations generated both by administered radiopharmaceuticals or by linear particle accelerators (LINACs). The radiotherapy beam delivered to the patient must be regularly checked to assure the best tumor control probability: this task is performed with dosimeters, i.e. devices able to provide a measurement of the dose deposited in their sensitive volume. This paper describes the development of two scintillator dosimeter prototypes for radiotherapic applications based on plastic scintillating fibers read out by high dynamic range Silicon PhotoMultipliers. The first dosimeter, consisting of a single-channel prototype with a pair of optical fibers, a scintillating and a white one, read out by two SiPMs, has been fully characterized and led to the development of a second multi-channel dosimeter based on an array of scintillating fibers: this device represents the first step towards the assembly of a "one-shot" device, capable to perform some of the daily quality controls in a few seconds. The dosimeters characterization was performed with a Varian Clinac iX linear accelerator at the Radiotherapy Department of the St. Anna Hospital in Como (IT).

  11. 128 slice computed tomography dose profile measurement using thermoluminescent dosimeter

    Science.gov (United States)

    Salehhon, N.; Hashim, S.; Karim, M. K. A.; Ang, W. C.; Musa, Y.; Bahruddin, N. A.

    2017-05-01

    The increasing use of computed tomography (CT) in clinical practice marks the needs to understand the dose descriptor and dose profile. The purposes of the current study were to determine the CT dose index free-in-air (CTDIair) in 128 slice CT scanner and to evaluate the single scan dose profile (SSDP). Thermoluminescent dosimeters (TLD-100) were used to measure the dose profile of the scanner. There were three sets of CT protocols where the tube potential (kV) setting was manipulated for each protocol while the rest of parameters were kept constant. These protocols were based from routine CT abdominal examinations for male adult abdomen. It was found that the increase of kV settings made the values of CTDIair increased as well. When the kV setting was changed from 80 kV to 120 kV and from 120 kV to 140 kV, the CTDIair values were increased as much as 147.9% and 53.9% respectively. The highest kV setting (140 kV) led to the highest CTDIair value (13.585 mGy). The p-value of less than 0.05 indicated that the results were statistically different. The SSDP showed that when the kV settings were varied, the peak sharpness and height of Gaussian function profiles were affected. The full width at half maximum (FWHM) of dose profiles for all protocols were coincided with the nominal beam width set for the measurements. The findings of the study revealed much information on the characterization and performance of 128 slice CT scanner.

  12. The influence of asymmetry in centralizing spring of squeeze film damper on stability and bifurcation of rigid rotor response

    Directory of Open Access Journals (Sweden)

    Hamidreza Heidari

    2016-12-01

    Full Text Available One of the main challenges in the design of rotating machinery is the occurrence of undesirable vibration. In this paper, stability and bifurcation of the unbalance response of a rigid rotor supported by squeeze film damper with asymmetry in centralizing spring are investigated. The unbalanced rotor response is determined by the shooting method and the stability of these solutions is examined by using the Floquet theorem. Numerical examples are given for both symmetric (Kx=Ky and asymmetry (Kx≠Ky centralizing springs in x or y direction. Jump phenomenon and subharmonic and quasi-periodic vibrations are predicted for a range of design and operating parameters such as the unbalancing (U, gravity (W, bearing (B and spring (K. The results show that increasing the spring stiffness asymmetry parameter in y direction has no influence on the nature of system response and occurrence of bifurcation. But, examining the effect of increase in stiffness parameter in x direction leads to occurrence instability and period-doubling bifurcation in response to the system. Our findings show that this phenomena are due to the weight force in the y direction. Finally, it is shown that the unsymmetrical stiffness of squeeze film dampers in the presence of cavitation promoting the chance of undesirable nonsynchronous vibrations.

  13. Thin film AlSb carrier transport properties and room temperature radiation response

    Science.gov (United States)

    Vaughan, Erin Ivey

    Theoretical predictions for AlSb material properties have not been realized using bulk growth methods. This research was motivated by advances in molecular beam epitaxial (MBE) growth technology to produce high-quality thin-film AlSb for the purpose of evaluating transport properties and suitability for radiation detection. Simulations using MCNP5 were performed to benchmark an existing silicon surface barrier detector and to predict ideal AlSb detector behavior, with the finding that AlSb should have improved detection efficiency due to the larger atomic number of Sb compared with Si. GaSb diodes were fabricated by both homoepitaxial MBE and ion implantation methods in order to determine the effect on the radiation detection performance. It was found that the radiation response for the MBE grown GaSb diodes was very uniform, whereas the ion-implanted GaSb diodes exhibited highly variable spectral behavior. Two sets of AlSb heterostructures were fabricated by MBE methods; one for a Hall doping study and the other for a radiation response study. The samples were characterized for material quality using transmission electron microscopy (TEM), Nomarski imaging, atomic force microscopy (AFM), x-ray diffraction (XRD), I-V curve analysis, and Hall effect measurements. The Hall study samples were grown on semi-insulating (SI) GaAs substrates and contained a thin GaAs layer on top to protect the AlSb from oxygen. Doping for the AlSb layer was achieved using GaTe and Be for n- and p-type conductivity, respectively, with intended doping densities ranging from 1015 to 1017 cm -3. Results for net carrier concentration ranged 2x10 9 to 1x1017 cm-3, 60 to 3000 cm 2/Vs for mobility, and 2 to 106 Ω-cm for resistivity, with the undoped AlSb samples presenting the best values. The radiation detector samples were designed to be PIN diodes, with undoped AlSb sandwiched between n-type GaAs substrate and p-type GaSb as a conductive oxygen-protective layer. Energy spectra were measured

  14. Pyroelectric response of spray-deposited BaTiO3 thin film

    Science.gov (United States)

    Peale, Robert E.; Oladeji, Isaiah O.; Smith, Evan M.; Vasilyev, Vladimir; Alhasan, Sarmad Fawzi Hamza; Abouelkhair, Hussain; Todorovski, Dalibor; Kimani, Martin; Cleary, Justin W.

    2016-09-01

    Pyroelectric photoresponse of aqueous spray deposited thin films containing BaTiO3 nano-crystals is reported. X-ray diffraction data indicate the presence of hexagonal BaTiO3 nano-crystals with 20 nm crystalline domains in a matrix of some as yet unidentified nano-crystalline material. When the film is annealed at 600 C, the X-ray pattern changes significantly and indicates a conversion to one of the non-hexagonal phases of BaTiO3 as well as a complete change in the matrix. With suitable amplifier, the measured photoresponse was 40V/W. Ferroelectric hysteresis on a film with significant presence of hexagonal BaTiO3 shows saturated polarization which is about 5-times smaller than for the bulk tetragonal phase. A potential application is a patternable infrared detector for photonic and plasmonic devices, such as chip-scale spectral sensors.

  15. Nonlinear response and two stable electroconducting states in transparent plasticized PVC films

    Science.gov (United States)

    Vlasov, D. V.; Apresyan, L. A.; Vlasova, T. V.; Kryshtob, V. I.

    2010-10-01

    The electric conductivity of transparent plasticized poly(vinyl chloride) (PVC) films with thicknesses about 30-50 μm has been studied in electric fields with strengths significantly below the breakdown level. It is established that the PVC films exhibit spontaneous reversible transitions between two stable states—with high and relatively low conductivities, in which the bulk resistivity amounts to ˜103 and 106 Ω m, respectively. Relaxation current-voltage characteristics have been measured in a continuous regime, which allowed the Debye relaxation processes to be taken into consideration and effects related to the nonlinearity and transitions between indicated states to be separated. A regime with deterministic switching between the two conducting states has been observed. A simple qualitative model that describes the anomalous character of conductivity in polymer films is proposed.

  16. Cathodoluminescence and green-thermoluminescence response of CaSO{sub 4}:Dy,P films

    Energy Technology Data Exchange (ETDEWEB)

    Roman-Lopez, J., E-mail: holand_jeos@hotmail.com [CICATA-IPN, Legaria 694, D.F. 11500, Mexico, CIEMAT, Av., Complutense 22, Madrid 28040 (Spain); Correcher, V. [CIEMAT, Av., Complutense 22, Madrid 28040 (Spain); Garcia-Guinea, J. [Museo Nacional de Ciencias Naturales (CSIC), Jose Gutierrez Abascal 2, Madrid 28006 (Spain); Rivera, T.; Lozano, I.B. [CICATA-IPN, Legaria 694, D.F. 11500 (Mexico)

    2013-03-15

    We herein report on the cathodoluminescence (CL) and green-thermoluminescence (TL) emission of CaSO{sub 4}:Dy,P films deposited by the spray pyrolysis method at different temperatures. The samples have been previously structurally and chemically characterized by means of Raman spectroscopy and energy dispersive spectroscopy (EDS). The CL spectra show (i) a broad emission band centered at 374 nm that corresponds to the intrinsic emission of (SO{sub 4}){sup 2-} and (ii) emission bands centered on 486, 574, 668, 758 nm assigned to the electronic transitions of the Dy{sup 3+} ions. The TL glow curves of the films showed three groups of components peaked at around of 98, 152 and 300 Degree-Sign C that exhibit a gradual and progressively linear shifting of the T{sub max} as function of T{sub stop}. This TL behavior is related to a continuum in the trap distribution associated with general or multi-order kinetics and involving continuous processes of trapping-detrapping. The activation energy in the range of 0.97-1.53 eV has been estimated using the initial rise method. - Highlights: Black-Right-Pointing-Pointer The CaSO{sup 4}:Dy,P films were prepared by using the ultrasonic spray pyrolysis method. Black-Right-Pointing-Pointer Luminescence spectra of the CaSO{sub 4}:Dy,P films display the emission bands of the ions (SO{sub 4}){sup 2-} and Dy{sup 3+}. Black-Right-Pointing-Pointer The CaSO{sub 4}:Dy,P films were irradiated with a {sup 90}Sr/{sup 90}Y beta source. Black-Right-Pointing-Pointer The TL intensity of the films depends on the temperature of deposit.

  17. Application of beam irradiation in preparation of visible light responsive TiO2 Films

    Institute of Scientific and Technical Information of China (English)

    HOU Xinggang; LIU Andong

    2007-01-01

    TiO2 films were prepared by sol-gel method.In order to improve the utilization of light, the technologiesof implantation of transition metal ions (V+ and Cr+) and electron beam irradiation to deposit noble metal particles (Ag and Pt) were used. A red shift was found in the spectrum of modified TiO2 films. The photocatalytic experiments showed that the photocatalytic ability under visible light irradiation could be improved dramatically by both the implantation of transition metal and the electron beam irradiation.

  18. A Scintillating Fiber Dosimeter for Radiology and Brachytherapy with photodiode readout

    CERN Document Server

    Rêgo, Florbela; Abreu, Maria da Conceição

    2011-01-01

    Purpose: For more than a decade that plastic optical fiber based dosimeters have been developed for medical applications. The feasibility of dosimeters using optical fibers that are almost Cherenkov light free has been demonstrated in some prototypes, particularly suitable for photon high-energy beams. In the energy range up to a few hundred keV, where the production of Cherenkov light by secondary electrons is negligible or small, the largest source of background are the fluorescence mechanisms. Methods: In recent years our group has developed an optical fiber dosimeter with photodiode readout named DosFib, which has small energy dependence in the range below 100 keV relevant for radiology. Photodiodes are robust photodetectors, presenting good stability over time and enough sensitivity to allow the use of an electrometer as a measuring device without extra electronics. Results: In-vitro tests using a High Dose Rate 192Ir source have demonstrated its suitability for brachytherapy applications using this impo...

  19. Considerations concerning the use of counting active personal dosimeters in pulsed fields of ionising radiation.

    Science.gov (United States)

    Ambrosi, Peter; Borowski, Markus; Iwatschenko, Michael

    2010-06-01

    Active personal electronic dosimeters (APDs) exhibit limitations in pulsed radiation fields, which cannot be overcome without the use of new detection technology. As an interim solution, this paper proposes a method by which some conventional dosimeters can be operated in a way such that, based on the basic knowledge about the pulsed radiation field, any dosimetric failure of the dosimeter is signalised by the instrument itself. This method is not applicable to all combinations of APD and pulsed radiation field. The necessary requirements for the APD and for the parameters of the pulsed radiation field are given in the paper. Up to now, all such requirements for APDs have not been tested or verified in a type test. The suitability of the method is verified for the use of one APD used in two clinical pulsed fields.

  20. A passive radon dosimeter based on the combination of a track etch detector and activated charcoal

    CERN Document Server

    Deynse, A V; Poffijn, A

    1999-01-01

    The aim of this work is to test a combination of a Makrofol track detector with a new type of charcoal (Carboxen-564) to design a personal radon dosimeter. The intention is to use this dosimeter as a personal radon dosimeter to measure the monthly radon exposure in workplaces, especially when the occupancy is not exactly known. The proposed combination was exposed to low and high concentrations of radon in a large range of relative humidity (RH). For the optimal layer thickness, a charcoal bed of 2.2 mm, a specific track density of 5.1 tracks cm sup - sup 2 /kBq h m sup - sup 3 was obtained. For a monthly working exposure (170 h) at an average radon concentration of 100 Bq/m sup 3 , this means 87 tracks/cm sup 2 or 10 times the background of the Makrofol detector, with a statistical uncertainty of 15%.

  1. SU-D-213-06: Dosimetry of Modulated Electron Radiation Therapy Using Fricke Gel Dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Gawad, M Abdel; Elgohary, M; Hassaan, M; Emam, M [Al Azhar University, Cairo Egypt (Egypt); Desouky, O [National center for radiation research and technology-Egyptian atomic energy, Cairo (Egypt); Eldib, A [Al Azhar University, Cairo Egypt (Egypt); Fox Chase Cancer Center, Philadelphia, PA (United States); Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States)

    2015-06-15

    Purpose: Modulated electron radiation therapy (MERT) has been proposed as an effective modality for treatment of superficial targets. MERT utilizes multiple beams of different energies which are intensity modulated to deliver optimized dose distribution. Energy independent dosimeters are thus needed for quantitative evaluations of MERT dose distributions and measurements of absolute doses delivered to patients. Thus in the current work we study the feasibility of Fricke gel dosimeters in MERT dosimetry. Methods: Batches of radiation sensitive Fricke gel is fabricated and poured into polymethyl methacrylate cuvettes. The samples were irradiated in solid water phantom and a thick layer of bolus was used as a buildup. A spectrophotometer system was used for measuring the color changes (the absorbance) before and after irradiation and then we calculate net absorbance. We constructed calibration curves to relate the measured absorbance in terms of absorbed dose for all available electron energies. Dosimetric measurements were performed for mixed electron beam delivery and we also performed measurement for segmented field delivery with the dosimeter placed at the junction of two adjacent electron beams of different energies. Dose measured by our gel dosimetry is compared to that calculation from our precise treatment planning system. We also initiated a Monte Carlo study to evaluate the water equivalence of our dosimeters. MCBEAM and MCSIM codes were used for treatment head simulation and phantom dose calculation. PDDs and profiles were calculated for electron beams incident on a phantom designed with 1cm slab of Fricke gel. Results: The calibration curves showed no observed energy dependence with all studied electron beam energies. Good agreement was obtained between dose calculated and that obtained by gel dosimetry. Monte Carlo results illustrated the tissue equivalency of our Gel dosimeters. Conclusion: Fricke Gel dosimeters represent a good option for the dosimetric

  2. On the development of a VIPARnd radiotherapy 3D polymer gel dosimeter

    Science.gov (United States)

    Kozicki, Marek; Jaszczak, Malwina; Maras, Piotr; Dudek, Mariusz; Cłapa, Marian

    2017-02-01

    This work presents an improvement of the VIPARnd (‘nd’ stands for ‘normoxic, double’, or VIP) polymer gel dosimeter. The gel composition was altered by increasing the concentration of the monomeric components, N-vinylpyrrolidone (NVP) and N,N‧-methylenebisacrylamide (MBA), in co-solvent solutions. The optimal composition (VIPARCT, where ‘CT’ stands for computed tomography, or VIC) comprised: 17% NVP, 8% MBA, 12% t-BuOH, 7.5% gelatine, 0.007% ascorbic acid, 0.0008% CuSO4  ×  5H2O and 0.02% hydroquinone. The following characteristics of VIC were achieved: (i) linear dose range of 0.9_30 Gy, (ii) saturation for radiation doses of over 50 Gy, (iii) threshold dose of about 0.5 Gy, (iv) dose sensitivity of 0.171 Gy-1 s-1, which is roughly 2.2 times higher than that of VIP (for nuclear magnetic resonance measurements). It was also found that VIC is dose- rate-independent, and its dose response does not alter if the radiation source is changed from electrons to photons for external beam radiotherapy. The gel responded similarly to irradiation with small changes in radiation energy but was sensitive to larger energy changes. The VIC gel retained temporal stability from 20 h until at least 10 d after irradiation, whereas spatial stability was retained from 20 h until at least 6 d after irradiation. The scheme adopted for VIC manufacturing yields repeatable gels in terms of radiation dose response. The VIC was also shown to perform better than VIP using x-ray computed tomography as a readout method; the dose sensitivity of VIC (0.397 HU Gy-1) was 1.5 times higher than that of VIP. Also, the dose resolution of VIC was better than that of VIP in the whole dose range examined.

  3. On the GHz frequency response in nanocrystalline FeXN ultra-soft magnetic films

    NARCIS (Netherlands)

    Chechenin, NG; Craus, CB; Chezan, AR; Vystavel, T; Boerma, DO; De Hosson, JTM; Niesen, L; Tidrow, SC; Horwitz, JS; Xi, XX; Levy, J

    2002-01-01

    The periodicity and angular spread of the in-plane magnetization for ultrasoft nanocrystalline FeZrN films were estimated from an analysis of the ripple structure, observed in Lorentz transmission electron microscopy (LTEM) images. The influence of the micromagnetic ripple on the ferromagnetic reson

  4. On the GHz frequency response in nanocrystalline FeXN ultra-soft magnetic films

    NARCIS (Netherlands)

    Chechenin, NG; Craus, CB; Chezan, AR; Vystavel, T; Boerma, DO; De Hosson, JTM; Niesen, L; Tidrow, SC; Horwitz, JS; Xi, XX; Levy, J

    2002-01-01

    The periodicity and angular spread of the in-plane magnetization for ultrasoft nanocrystalline FeZrN films were estimated from an analysis of the ripple structure, observed in Lorentz transmission electron microscopy (LTEM) images. The influence of the micromagnetic ripple on the ferromagnetic reson

  5. Sub-nanometer expansions of redox responsive polymer films monitored by imaging ellipsometry

    NARCIS (Netherlands)

    Cumurcu, Aysegul; Feng, X.; Dos Ramos, L.; Hempenius, M.A.; Schon, P.M.; Vancso, G.J.

    2014-01-01

    We describe a novel approach to quantitatively visualize sub nm height changes occurring in thin films of redox active polymers upon reversible electrochemical oxidation/reduction in situ and in real-time with electrochemical imaging ellipsometry (EC-IE). Our approach is based on the utilization of

  6. Piezoelectric response of a PZT thin film to magnetic fields from permanent magnet and coil combination

    Science.gov (United States)

    Guiffard, B.; Seveno, R.

    2015-01-01

    In this study, we report the magnetically induced electric field E 3 in Pb(Zr0.57Ti0.43)O3 (PZT) thin films, when they are subjected to both dynamic magnetic induction (magnitude B ac at 45 kHz) and static magnetic induction ( B dc) generated by a coil and a single permanent magnet, respectively. It is found that highest sensitivity to B dc——is achieved for the thin film with largest effective electrode. This magnetoelectric (ME) effect is interpreted in terms of coupling between eddy current-induced Lorentz forces (stress) in the electrodes of PZT and piezoelectricity. Such coupling was evidenced by convenient modelling of experimental variations of electric field magnitude with both B ac and B dc induction magnitudes, providing imperfect open circuit condition was considered. Phase angle of E 3 versus B dc could also be modelled. At last, the results show that similar to multilayered piezoelectric-magnetostrictive composite film, a PZT thin film made with a simple manufacturing process can behave as a static or dynamic magnetic field sensor. In this latter case, a large ME voltage coefficient of under B dc = 0.3 T was found. All these results may provide promising low-cost magnetic energy harvesting applications with microsized systems.

  7. In vivo dosimetry thermoluminescence dosimeters during brachytherapy with a 370 GBq {sup 192}Ir source

    Energy Technology Data Exchange (ETDEWEB)

    Cuepers, S.; Piessens, M.; Verbeke, L.; Roelstraete, A. [Onze-Lieve-Vrouw Hospitaal, Aalst (Belgium). Dept. of Radiotherapy and Oncology

    1995-12-01

    When using LiF thermoluminescence dosimeters in brachytherapy, we have to take into account the properties of a high dose rate {sup 192}Ir source (energy spectrum ranging form 9 to 885 keV, steep dose gradient in the vicinity of the source) and these of the dosimeters themselves (supralinearity, reproducibility, size). All these characteristics combine into a set of correction factors which have been determined during in phantom measurements. These results have then been used to measure the dose delivered to organs at risk (e.g. rectum, bladder, etc.) during high dose rate brachytherapy with a 370 GBq {sup 192}Ir source for patients with gyn