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Sample records for radiocromic film tld

  1. Radiocromic film, TLD, OSL and 'Paracas Phantom' by dosimetric intercomparation in stereotactic radiosurgery

    International Nuclear Information System (INIS)

    Paucar Jauregui, R.; Condori Marcos, P.; Vidarte Garcia, F.

    2008-01-01

    Full text: In Peru, one deals to patients with arteriovenous malformations or cerebral tumors by means of stereotactic radiosurgery, using fine photon beams of high energy of 6 MeV, generated by a linear accelerator Varian 2100 Clinac CD of the Complejo Hospitalario San Pablo in Lima, Peru. In this work we describes the 'Dosimetric Intercomparation System of the Quality Assurance Program in Stereotactic Radiosurgery of the Complejo Hospitalario San Pablo (DIS)'. The DIS allows to guarantee application of the doses with high accuracy. It shows the good performance of the Local DIS's components: dosimetry of radiocromics films, dosimetry termoluminiscent (TLD), dosimetry of optically stimulated luminescence (OSL) and an anthropomorphic phantom of head constructed locally, denominated 'Paracas Phantom'. Also, in the International DIS practiced with The University of Texas Md Anderson Cancer Center, stands out results within the ranges: a) Dose to the center of the target (RDS/Institution): 0,95-1,05; b) Treated volumen (Measured/Institution): 0,75 - 1,05; c) Ratio of measure treated volume to target volume: 1,00 - 2,00; and d) Minimum dose to target (Minimum dose/Prescription dose): >0,90. It concludes that the DIS is important for the good decision making on the radiological safety of the patients dealt with stereotactic radiosurgery. (author)

  2. Data processing of personnel exposure in TLD and film systems

    International Nuclear Information System (INIS)

    Lerner, A.; Liav, N.; Eisen, Y.

    1979-01-01

    The program for the processing and storage of data on the personnel irradiation exposure in Israel is built on the data base of the Weizmann Institute of Science; it is a general program suitable for both TLD and film dosimetry. The TSO system helped bring up-to-date the data of the various collections in an interactive way. The introduction of the TLD dosemeters in the badge service required certain changes in the thinking line - this because the TLD being a personal dosemeter is returned into service after having been deciphered. This demands following up the dosemeter when the worker moves from unit to unit or after he had finished his work. The program takes into account the internal exposures,too and conforms to the new recommendation published in ICRP-26. (B.G.)

  3. Dose rate dependence for different dosimeters and detectors: TLD, OSL, EBT films, and diamond detectors

    International Nuclear Information System (INIS)

    Karsch, L.; Beyreuther, E.; Burris-Mog, T.; Kraft, S.; Richter, C.; Zeil, K.; Pawelke, J.

    2012-01-01

    Purpose: The use of laser accelerators in radiation therapy can perhaps increase the low number of proton and ion therapy facilities in some years due to the low investment costs and small size. The laser-based acceleration technology leads to a very high peak dose rate of about 10 11 Gy/s. A first dosimetric task is the evaluation of dose rate dependence of clinical dosimeters and other detectors. Methods: The measurements were done at ELBE, a superconductive linear electron accelerator which generates electron pulses with 5 ps length at 20 MeV. The different dose rates are reached by adjusting the number of electrons in one beam pulse. Three clinical dosimeters (TLD, OSL, and EBT radiochromic films) were irradiated with four different dose rates and nearly the same dose. A faraday cup, an integrating current transformer, and an ionization chamber were used to control the particle flux on the dosimeters. Furthermore two diamond detectors were tested. Results: The dosimeters are dose rate independent up to 410 9 Gy/s within 2% (OSL and TLD) and up to 1510 9 Gy/s within 5% (EBT films). The diamond detectors show strong dose rate dependence. Conclusions: TLD, OSL dosimeters, and EBT films are suitable for pulsed beams with a very high pulse dose rate like laser accelerated particle beams.

  4. Parallel analysis of film and TLD application in personal dosimetry of medical staff during application of invasive radiological procedures

    International Nuclear Information System (INIS)

    Misovic, M.; Boskovic, Z.; Spasic-Jokic, V.

    1997-01-01

    Although both types of dosimeters showed similar results for mentioned category of health care workers we wished to emphasize some advantages in use of TLD and film dosemeters in personal dosimetry. The main advantageous of film for dosimetric purposes are that it can provide visual representation of the radiation field and they are cheap, but there are lot of disadvantages. Advantages of TLD are based on: possibility for re-use, practically for whole users working life, small dimensions suitable for results, high precision and specially wide dose range. They are sensitive on low dose, practically for ten times more than film is. Disadvantages of TLD are based on their previous thermal and radiation history and on the fact that information about dose disappears after reading procedure. Considering advantages and disadvantages of both types of dosemeters we decided to propose TLD for routine hospital practice in personal dosimetry. (author)

  5. Reproducibility Test for Thermoluminescence Dosimeter (TLD) Using TLD Radpro

    International Nuclear Information System (INIS)

    Nur Khairunisa Zahidi; Ahmad Bazlie Abdul Kadir; Faizal Azrin Abdul Razalim

    2016-01-01

    Thermoluminescence dosimeters (TLD) as one type of dosimeter which are often used to substitute the film badge. Like a film badge, it is worn for a period of time and then must be processed to determine the dose received. This study was to test the reproducibility of TLD using Radpro reader. This study aimed to determine the dose obtained by TLD-100 chips when irradiated with Co-60 gamma source and to test the effectiveness of TLD Radpro reader as a machine to analyse the TLD. Ten chips of TLD -100 were irradiated using Eldorado machine with Co-60 source at a distance of 5 meters from the source with 2 mSv dose exposure. After the irradiation process, TLD-100 chips were read using the TLD Radpro reader. These steps will be repeated for nine times to obtain reproducibility coefficient, r i . The readings of dose obtained from experiment was almost equivalent to the actual dose. Results shows that the average value obtained for reproducibility coefficient, r i is 6.39 % which is less than 10 %. As conclusion, the dose obtained from experiment considered accurate because its value were almost equivalent to the actual dose and TLD Radpro was verified as a good reader to analyse the TLD. (author)

  6. Experimental comparison of profiles of acquired small fields with ionization chambers, diodes, radiochromic s and TLD films

    International Nuclear Information System (INIS)

    Venencia, D.; Garrigo, E.; Filipuzzi, M.; Germanier, A.

    2014-08-01

    The use of radiation small fields, introduced by new techniques, can bring a considerable uncertainty in the precision of the acquired profiles, due to the conditions of lateral electronic non-equilibrium and the perturbations introduced by the detectors (volume effect and alteration of the charged particles flowing) [Das et al., 2007]. The development of new miniature detectors looks to diminish the uncertainty created by the material and the size of the sensitive volume of the dosimeter. For this reason, comparative measurements for three sizes of square field were carried out (20 mm, 10 mm and 5 mm, of side) using a detectors series: 3 ionization chambers (PTW-31003, IBA-CC04, PTW-31016), 2 diodes (PTW-60012, IBA-Sfd), thermoluminescent detectors micro-cubes of 1 mm of edge (TLD-700) and radiochromic s films EBT-3. These last two were used as reference detectors, due to their spatial high resolution and similar performance with Monte Carlo simulations [Francescon et al., 1998]. So much the thermoluminescent detectors as the radiochromic films resolved the profiles in a similar way. Both diodes responded correctly, but the rest of the detectors overestimated the gloom of the fields, which allows conclude that the used TLD (and both diodes) can resolve field sizes correctly, usually utilized in radio-surgery, without producing significant alterations in the acquired data. (author)

  7. The intercomparison of 137Cs irradiator output measurement and personal dose equivalent, Hp(10), using TLD and film

    International Nuclear Information System (INIS)

    Nazaroh; Susetyo Trijoko; Sri Inang Sunaryati

    2010-01-01

    Intercomparison of output measurement of 137 Cs irradiator and personal dose equivalent, Hp(10) using TLD and film have been carried out in the year of 2006 to 2008. According to IAEA recommendation, intercomparison is one of audit activities but it is performed in the spirit of collaboration and support rather than in the spirit of inspection. The aim of intercomparison of output measurement of 137 Cs irradiator is to verify the dose stated by the participant laboratories. Intercomparison is also to assess the competency of the participant, to keep traceability and consistency of measurement result, to assure that instrument work correctly and the result of evaluation was in agreement, and also for fulfilling one of the clauses of ISO-17025-2005. Besides that, this intercomparison aimed to facilitate link between the system and members of national measurement and transfer of experience in measurement technique and dose evaluation of radiation. The benefit of intercomparison is important among others as tests of proficiency in dose evaluation or measurement, upgrading quality of service and for obeying supervisor body legislation (BAPETEN). TLD was used as a means of output 137 Cs irradiator measurement, whereas film and TLD were used for dose intercomparison. This paper presented result of intercomparison of output measurement and evaluation of personal dose equivalent, Hp(10) in the year of 2006 to 2008 followed by 6 participants: Balai Pengamanan Fasilitas Kesehatan (BPFK) Jakarta, Medan, Surabaya, Makasar, PTLR and Laboratory of Keselamatan dan Kesehatan Lingkungan (KKL)-PTKMR BATAN. In this intercomparison, the dose of TLD stated by participant were compared with the dose measured by Radiation Metrology Laboratory (LMR), and the results showed the differences were within 10 %, so it was satisfied. The results of intercomparison of personal dose equivalent, Hp(10) were evaluated based on ISO/IEC Guide 43-1, 1997 analysis and expressed as E n . The values of E n

  8. Experimental comparison of profiles of acquired small fields with ionization chambers, diodes, radiochromic s and TLD films; Comparacion experimental de perfiles de campos pequenos adquiridos con camaras de ionizacion, diodos, peliculas radiocromicas y TLD

    Energy Technology Data Exchange (ETDEWEB)

    Venencia, D.; Garrigo, E. [Instituto Privado de Radioterapia, Obispo Oro 423, X5000BFI Cordoba (Argentina); Filipuzzi, M. [Instituto Balseiro, Centro Atomico Bariloche, Av. Bustillo 9500, 8400 Bariloche - Rio Negro (Argentina); Germanier, A., E-mail: devenencia@radioncologia-zunino.org [Centro de Excelencia en Productos y Procesos, Santa Maria de Punilla, 5164 Cordoba (Argentina)

    2014-08-15

    The use of radiation small fields, introduced by new techniques, can bring a considerable uncertainty in the precision of the acquired profiles, due to the conditions of lateral electronic non-equilibrium and the perturbations introduced by the detectors (volume effect and alteration of the charged particles flowing) [Das et al., 2007]. The development of new miniature detectors looks to diminish the uncertainty created by the material and the size of the sensitive volume of the dosimeter. For this reason, comparative measurements for three sizes of square field were carried out (20 mm, 10 mm and 5 mm, of side) using a detectors series: 3 ionization chambers (PTW-31003, IBA-CC04, PTW-31016), 2 diodes (PTW-60012, IBA-Sfd), thermoluminescent detectors micro-cubes of 1 mm of edge (TLD-700) and radiochromic s films EBT-3. These last two were used as reference detectors, due to their spatial high resolution and similar performance with Monte Carlo simulations [Francescon et al., 1998]. So much the thermoluminescent detectors as the radiochromic films resolved the profiles in a similar way. Both diodes responded correctly, but the rest of the detectors overestimated the gloom of the fields, which allows conclude that the used TLD (and both diodes) can resolve field sizes correctly, usually utilized in radio-surgery, without producing significant alterations in the acquired data. (author)

  9. Personal exposure control using TLD

    International Nuclear Information System (INIS)

    Ishiguro, Hideharu; Takeda, Shinso

    1979-01-01

    In the Tokai Works of the Power Reactor and Nuclear Fuel Development Corporation (PNC), for personal exposure control, the switching from film badges to TLD badges (and also finger-ring type local dosimeters) was made in fiscal 1974. The facilities involved are a fuel reprocessing plant, a PuO 2 -UO 2 mixed fuel production facility, and a centrifugal uranium enrichment development facility. The types of radiation concerned are various, such as γ(x), β and n. The situation of personal exposure control with TLD and the dose evaluation methods for respective radiations are explained. The number of personnel subject to exposure control, including transient people, is about 2500 - 3000 per three months. The TLD badges used are a special PNC type with TLDs to measure separately γ(x), β and n. With casings made of ABS resin, the external dimensions are 76 mm x 46 mm. (J.P.N.)

  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

    International Nuclear Information System (INIS)

    Vega R, J. L.; Cayllahua, F.; Apaza, D. G.; Javier, H.

    2015-10-01

    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 2 and 1 x 1 cm 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. The quality of dental radiography in the Czech Republic - Results of a TLD and film postal audit

    International Nuclear Information System (INIS)

    Novak, L.

    2006-01-01

    Since 2002, the postal audit in dental radiography has been supplementing standard quality control (QC) tools for dental intraoral X-ray machines. An aim of the audit is to check basic X-ray machine parameters (field size, exposure reproducibility), and a quality of the whole process of diagnostic imaging (entrance surface air-kerma measurement, a check of film processing and an image quality evaluation). The standard QC tests, performed by private companies, check mainly the X-ray unit. Conversely, the audit gives better information about the patient examination practices. During the period of January 2002 to May 2004 ∼4000 audits were performed. The results confirmed that main problems in dental radiography are due to incorrect film processing, non-optimised setting of the exposure parameters and use of obsolete X-ray machines. Only ∼30% of performed audits were satisfactory with respect to all checked parameters. (authors)

  12. 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)

  13. TLD audit in the radiotherapy at the national level

    International Nuclear Information System (INIS)

    Kroutilikova, D.; Zackova, H.; Novotny, J.; Pridal, I.

    1998-01-01

    Czech legislation requires that all radiotherapy departments undertake quality independent audit annually. An authorized auditing group was created as a body of the National Radiation Protection Institute. It has been decided that TLD postal audit combined with film dosimetry would alternate with in situ audit every two or three years. For this, a local TLD measuring network has been established. The methods applied in the TLD audit were taken from EROPAQ and EURAQA projects in 1996 and modified to comply with Czech local circumstances. First TLD audits were started in February 1997. During the February to September period, 60 beams were checked: 26 Co-60 beams, 10 Cs-137 beams, 15 X-ray beams, and 9 electron beams. Details of the measurements and their results are given. (P.A.)

  14. Optimal selection of TLD chips

    International Nuclear Information System (INIS)

    Phung, P.; Nicoll, J.J.; Edmonds, P.; Paris, M.; Thompson, C.

    1996-01-01

    Large sets of TLD chips are often used to measure beam dose characteristics in radiotherapy. A sorting method is presented to allow optimal selection of chips from a chosen set. This method considers the variation

  15. TLD array for precise dose measurements in stereotactic radiation techniques

    International Nuclear Information System (INIS)

    Ertl, A.; Kitz, K.; Griffitt, W.; Hartl, R.F.E.; Zehetmayer, M.

    1996-01-01

    We developed a new TLD array for precise dose measurement and verification of the spatial dose distribution in small radiation targets. It consists of a hemicylindrical, tissue-equivalent rod made of polystyrene with 17 parallel moulds for an exact positioning of each TLD. The spatial resolution of the TLD array was evaluated using the Leskell spherical phantom. Dose planning was performed with KULA 4.4 under stereotactic conditions on axial CT images. In the Leksell gamma unit the TLD array was irradiated with a maximal dose of 10 Gy with an unplugged 14 mm collimator. The doses delivered to the TLDs were rechecked by diode detector and film dosimetry and compared to the computer-generated dose profile. We found excellent agreement of our measured values, even at the critical penumbra decline. For the 14 mm and 18 mm collimator and for the 11 mm collimator combination we compared the measured and calculated data at full width at half maximum. This TLD array may be useful for phantom or tissue model studies on the spatial dose distribution in confined radiation targets as used in stereotactic radiotherapy. (author)

  16. Environmental effects on TLD 100

    International Nuclear Information System (INIS)

    Lilley, E.; Howard, R.

    1976-01-01

    Reference is made to a recent paper by Dhar et al (Health Phys.; 25:427 (1973)) in which significant differences in the sensitivity of TLD 100 crystals following the same heat treatments in different environments, were reported. Similar work is here reported on TLD 100 at 400 0 C with half the crystals being heat treated in vacuum, irradiated and readout an then annealed in air, irradiated and readout while the other half of the crystals were air annealed and readout before vacuum annealing and readout. In both cases no significant change was detected in contrast to the results of Dhar et al. (U.K.)

  17. Minimizing TLD-DRD differences

    International Nuclear Information System (INIS)

    Riley, D.L.; McCoy, R.A.; Connell, W.D.

    1987-01-01

    When substantial differences exist in exposures recorded by TLD's and DRD's, it is often necessary to perform an exposure investigation to reconcile the difference. In working with several operating plants, the authors have observed a number of causes for these differences. This paper outlines these observations and discusses procedures that can be used to minimize them

  18. A new TLD system for space research

    International Nuclear Information System (INIS)

    Feher, I.; Deme, S.; Szabo, B.; Vagvoelgyi, J.; Szabo, P.P.; Csoeke, A.; Ranky, M.; Akatov, Yu.A.

    1980-06-01

    A small, portable, vibration and shock resistant thermoluminescent dosemeter (TLD) system was developed to measure the cosmic radiation dose on board of a spacecraft. The TLD system consists of a special bulb dosemeter and a TLD reader. The measuring dose range of the TLD system is from 10 μGy up to 100 mGy. The TLD reader can operate on a battery; its electrical power consumption is about 5 W, its volume is about 1 dm 3 and its mass is about 1 kg. Details are given of the construction and technical parameters of the dosemeter and reader. (author)

  19. Postal TLD audits in radiotherapy in the Czech Republic: current status, experience and potential

    International Nuclear Information System (INIS)

    Ekendahl, Daniela; Kapucianova, Michaela; Dufek, Vladimir

    2014-01-01

    The paper deals with practice and performance of postal TLD audits in radiotherapy with emphasis on the possibilities of application of the advanced versions that were developed following up technological progress in radiotherapy. The new methodologies of the TLD audit are focused specifically on up-to-date linear accelerators, equipped with multileaf collimators, and modern treatment planning systems. The dose is checked by the TLD not only for reference conditions but also in conditions of radiation fields influenced by presence of inhomogeneities in the irradiated volume. As regards small radiation fields, the check also includes dose profile verification using gafchromic films. The methodologies were tested within pilot studies performed in collaboration with some Czech radiotherapy centers. The results and experience gave evidence of the usefulness and appropriateness of the new TLD audit methodologies. (orig.)

  20. Environmental monitoring with a portable TLD system

    Energy Technology Data Exchange (ETDEWEB)

    Szabo, P P; Feher, I; Deme, S; Szabo, B; Vagvoelgyi, J; German, E [Hungarian Academy of Sciences, Budapest. Central Research Inst. for Physics

    1984-01-01

    Two types of TLD systems are used for environmental dose monitoring. One is based on an NHZ-203 laboratory TLD reader and CaSO/sub 4/:Dy powder. The other is based on CaSO/sub 4/:Tm bulbs and a small, portable TLD reader built into a cross-country car and operated by means of the car battery. The laboratory TLD system has been used for many years for environmental monitoring and it has been tested and proved satisfactory at international intercomparisons for environmental dosemeters. The new portable TLD system has the advantage of being able to establish the dose in a few minutes at the environmental station. The transport dose is omitted as the TLDs are evaluated at the field site. The evaluation of a bulb needs only a few minutes and the measured dose value can be reported back by radio - an important aspect during an emergency situation.

  1. Centralized TLD service and record keeping in Canada

    International Nuclear Information System (INIS)

    Grogan, D.; Ashmore, J.P.; Bradley, R.P.

    1979-01-01

    A centralized automated TLD service operated by the Department of National Health and Welfare went into operation in May 1977 to monitor radiation workers throughout Canada. Twenty-thousand employees from a wide range of disciplines are enrolled and the number will be increased to fifty thousand by September l978. A prototype of the system, operational from September 1976 to May 1977 for three-thousand people, has already been described. A description of technical and operational highlights is presented as well as a description of problems experienced during the first full year of operation. Details of costs, conversion logistics, operational performance and technical problems are included. A comparison of the advantages and disadvantages of changing from film dosimetry to TLD in a nationwide context is detailed. The dose meter read-out unit is interfaced, through video terminals, with a time-sharing computer system programmed to provide direct access to the Canadian National Dose Registry. Details of this linkage are described, as are the computer programmes for routine processing of raw batch data. The centralized TLD service interactively linked with the National Dose Registry provides a comprehensive occupational monitoring programme invaluable for regulatory control. (author)

  2. An automated thermoluminescence dosimetry (TLD) system

    International Nuclear Information System (INIS)

    Kicken, P.J.H.; Huyskens, C.J.

    1979-01-01

    In the Health Physics Division of the Eindhoven University of Technology work is going on in developing an automated TLD-system. Process automization, statistical computation, dose calculation as well as dose recording are carried out, using a microcomputer and floppy disk unit. The main features of this TLD-system are its low costs, flexibility, easy to operate, and the feasibility for use in routine dosimetry as well as in complex TLD research. Because of its modular set-up several components of the system are multifunctional in other operations. The system seems suited for medium sized Health Physics groups. (Auth.)

  3. NRC TLD Direct Radiation Monitoring Network

    International Nuclear Information System (INIS)

    Struckmeyer, R.; McNamara, N.

    1991-12-01

    This report provides the status and results of the NRC Thermoluminescent Dosimeter (TLD) Direct Radiation Monitoring Network. It presents the radiation levels measured in the vicinity of NRC licensed facilities throughout the country for the third quarter of 1991

  4. Automated TLD system for gamma radiation monitoring

    International Nuclear Information System (INIS)

    Nyberg, P.C.; Ott, J.D.; Edmonds, C.M.; Hopper, J.L.

    1979-01-01

    A gamma radiation monitoring system utilizing a commercially available TLD reader and unique microcomputer control has been built to assess the external radiation exposure to the resident population near a nuclear weapons testing facility. Maximum use of the microcomputer was made to increase the efficiency of data acquisition, transmission, and preparation, and to reduce operational costs. The system was tested for conformance with an applicable national standard for TLD's used in environmental measurements

  5. Personnel dose equivalent monitoring at SLAC using lithium-fluoride TLD's [thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    Jenkins, T.M.; Busick, D.D.

    1987-03-01

    TLD's replaced film badges in the early 1970's for all dose equivalent monitoring, both neutron and photon, and for all locations at SLAC. The photon TLD's, composed of Li-7 loaded teflon discs, are calibrated using conventional gamma-ray sources; i.e., Co-60, Cs-137, etc. For these TLD's a nominal value of 1 nC/mrem is used, and is independent of source energy for 100 keV to 3 MeV. Since measured dose equivalents at SLAC are only a small fraction of the allowable levels, it was not deemed necessary to develop neutron dosimeters which would measure dose equivalent accurately for all possible neutron spectra. Today, wallet TLD's, composed of pairs of Li-7 and Li-6 discs, are used, with the Li-6 measuring only thermal neutrons; i.e., they aren't moderated in any way to make them sensitive to neutrons with energies greater than thermal. The assumption is made that there is a correlation between thermal neutron fluences and fast neutron fluences around the research area where almost all neutron doses (exclusive of sealed sources) are received. The calibration factor for these Li-6 TLD's is 1 nC/mrem of fast neutrons. The method of determining the validity of this calibration is the subject of this note. 4 refs., 9 figs., 1 tab

  6. Environmental monitoring system with TLD

    International Nuclear Information System (INIS)

    Aguerre, L.; Carelli, J.; Gregori, B.

    2006-01-01

    Presently work the methodology used by the Laboratory of Thermoluminescent Dosimetry (TLD) of the Nuclear Regulatory Authority (RNA) to gauge it system of environmental monitoring in function of the media absorbed dose rate in free air and the environmental dose equivalent, H * (10), according to the recommendation ICRU Report 47 is described. It was studied the response of the environmental dosemeter (DA) in fields of photonic radiation of energies W60, Wl 10, W200 and 137 Cs. The irradiations were carried out following the recommendations of the standard ISO:4037. It was analyzed the response in the DA of the detectors LiF: Mg, Ti and CaF 2 : Dy for the different radiation qualities and the relative response at 137 Cs of both. The methodology used in the evaluation of the dose includes: the correction of the readings of both detectors by fading, gotten experimentally, the witness of transfers, the energy answer and the value of the zero. The dose is calculated applying the average pondered in uncertainty of the dose obtained for each type of detector. Its were analyzed and calculated the uncertainties that affect to the measurement following the recommendation of the Argentine standard IRAM 35050. The detection limit of the absorbed dose rate in free air of this system it is 3.5 n Gy/h for a period of sampling of 3 months. With this detection limit environmental dose equivalent rates of the order of 70 n Sv/h are measured with an expanded uncertainty of the order of 10% with a cover factor k = 2. (Author)

  7. A new fully automated TLD badge reader

    International Nuclear Information System (INIS)

    Kannan, S.; Ratna, P.; Kulkarni, M.S.

    2003-01-01

    At present personnel monitoring in India is being carried out using a number of manual and semiautomatic TLD badge Readers and the BARC TL dosimeter badge designed during 1970. Of late the manual TLD badge readers are almost completely replaced by semiautomatic readers with a number of performance improvements like use of hot gas heating to reduce the readout time considerably. PC based design with storage of glow curve for every dosimeter, on-line dose computation and printout of dose reports, etc. However the semiautomatic system suffers from the lack of a machine readable ID code on the badge and the physical design of the dosimeter card not readily compatible for automation. This paper describes a fully automated TLD badge Reader developed in the RSS Division, using a new TLD badge with machine readable ID code. The new PC based reader has a built-in reader for reading the ID code, in the form of an array of holes, on the dosimeter card. The reader has a number of self-diagnostic features to ensure a high degree of reliability. (author)

  8. Neutron area monitor with TLD pairs

    International Nuclear Information System (INIS)

    Guzman G, K. A.; Borja H, C. G.; Valero L, C.; Hernandez D, V. M.; Vega C, H. R.

    2011-11-01

    The response of a passive neutron area monitor with pairs of thermoluminescent dosimeters has been calculated using the Monte Carlo code MCNP5. The response was calculated for one TLD 600 located at the center of a polyethylene cylinder, as moderator. When neutrons collide with the moderator lose their energy reaching the TLD with thermal energies where the ambient dose equivalent is calculated. The response was calculated for 47 monoenergetic neutron sources ranging from 1E(-9) to 20 MeV. Response was calculated using two irradiation geometries, one with an upper source and another with a lateral source. For both irradiation schemes the response was calculated with the TLDs in two positions, one parallel to the source and another perpendicular to the source. The advantage of this passive neutron monitor area is that can be used in locations with intense, pulsed and mixed radiation fields. (Author)

  9. Improvements of RGD3 TLD reader

    International Nuclear Information System (INIS)

    Zhao Jianxing; Wang Jiaqi; Li Yuanfang; Wu Furong; Xiao Wuyun

    1999-01-01

    The author summarized the main features of the improved RGD3 TLD reader. Through a large number of experiments some persuasive data are obtained, which show that an remarkable improvement has been achieved, especially in its stability to the standard illuminates, data dispersivity, and effectiveness to glow curves analysis. Working with the newly developed data processing software, the comprehensive performance of the whole system will be enhanced greatly

  10. Determination of the TLD-100 physical parameters

    International Nuclear Information System (INIS)

    Paucar J, J.; Picon C, C.

    1998-01-01

    This study was realized in the Physics service at the Radiotherapy Department of the National Institute of Neoplasic Diseases in Lima, Peru, it was determined the activation energy, the kinetic order and the frequency factor of the fifth peak of the TLD-100 thermoluminescent spectra using different algorithms. This was carried out in parallel with the implementation and design of a software and an interface associated with the Tl lecturer which allows a semiautomatic control for a thermoluminescent lecturer process. (Author)

  11. Microcomputer control of automated TLD reader

    International Nuclear Information System (INIS)

    Bjarland, Bert.

    1979-10-01

    The interfacing electronics, the control algorithms and the developed programs of a 6800 microcomputer controlled automated TLD reader are described. The TL reading system is implemented with a photomultiplier tube and a charge-to-pulse converter. The gain of the TL reading system is controlled through the use of a temperature compensated LED reference light source. Automatic compensation of PM tube dark current is optional. The short term stability of TL readings is better than 3 %. (author)

  12. Ionizing radiation source detection by personal TLD

    International Nuclear Information System (INIS)

    Marinkovic, O.; Mirkov, Z.

    2002-01-01

    The Laboratory for personal dosimetry has about 3000 workers under control. The most of them work in medicine. Some institutions, as big health centers, have different ionizing radiation sources. It is usefull to analyze what has been the source of irradiation, special when appears a dosimeter with high dose. Personal dosimetry equipment is Harshaw TLD Reader Model 6600 and dosimeters consist of two chips LiF TLD-100 assembled in bar-coded cards which are wearing in holders with one tissue-equivalent filter (to determine H(10)) and skin-equivalent the other (to determine H(0.07)). The calibration dosimeters have been irradiated in holders by different sources: x-ray (for 80keV and 100keV), 6 0C o, 9 0S r (for different distances from beta source) and foton beem (at radiotherapy accelerator by 6MeV, 10MeV and 18MeV). The dose ratio for two LiF cristals was calculated and represented with graphs. So, it is possible to calculate the ratio H(10)/H(0.07) for a personal TLD and analyze what has been the source of irradiation. Also, there is the calibration for determination the time of irradiation, according to glow curve deconvolution

  13. Next Generation Model 8800 Automatic TLD Reader

    International Nuclear Information System (INIS)

    Velbeck, K.J.; Streetz, K.L.; Rotunda, J.E.

    1999-01-01

    BICRON NE has developed an advanced version of the Model 8800 Automatic TLD Reader. Improvements in the reader include a Windows NT TM -based operating system and a Pentium microprocessor for the host controller, a servo-controlled transport, a VGA display, mouse control, and modular assembly. This high capacity reader will automatically read fourteen hundred TLD Cards in one loading. Up to four elements in a card can be heated without mechanical contact, using hot nitrogen gas. Improvements in performance include an increased throughput rate and more precise card positioning. Operation is simplified through easy-to-read Windows-type screens. Glow curves are displayed graphically along with light intensity, temperature, and channel scaling. Maintenance and diagnostic aids are included for easier troubleshooting. A click of a mouse will command actions that are displayed in easy-to-understand English words. Available options include an internal 90 Sr irradiator, automatic TLD calibration, and two different extremity monitoring modes. Results from testing include reproducibility, reader stability, linearity, detection threshold, residue, primary power supply voltage and frequency, transient voltage, drop testing, and light leakage. (author)

  14. TLD territorial network in the Czech Republic

    Energy Technology Data Exchange (ETDEWEB)

    Kroutilikova, D. [National Radiation Protection Institute, Prague (Czech Republic)

    1996-12-31

    At present, there are 236 measuring points practically homogeneously distributed on the territory of the Czech Republic. 98 measuring points are distributed as local TLD-networks in the surroundings of Czech two nuclear power plants. Both of the TLD-networks are operated by the National Radiation Protection Institute in Prague. The dosimeters hitherto used are the CaSO{sub 4}:Dy-teflon detectors placed in TL-badges and shielded on both sides by energy compensation filters composed of lead and tin. Recently, a new modernization of the measuring system, type of dosimeter and methods of evaluation is under way. From 1996 the Czech Radiation Monitoring Network will be used the TLD system HARSHAW 4000, along with the type 8807 ENVIRONMENTAL DOSIMETER. The dosimeter is composed of four TL-elements - two LiF and two CaF{sub 2}, placed in a plastic badge. In addition, the CaF{sub 2} elements are shielded on both sides by energy compensation filters composed of tantalum and lead. Before the routine use of the new system a testing of the dosimeters was made. The following text summarizes the obtained results (J.K.). 4 tabs.

  15. How to diagnose any type of TLD Reader?; Como diagnosticar cualquier tipo de TLD Reader?

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Manuel Lopez; Garcia, Jose A. Tamayo; Gil, Alex Vergara; Lores, Stefan Gutierrez; Acosta, Andry Romero; Villanueva, Gilberto Alonso, E-mail: manolo@cphr.edu.cu, E-mail: jotag@cphr.edu.cu, E-mail: alex@cphr.edu.cu, E-mail: stefan@cphr.edu.cu, E-mail: andy@cphr.edu.cu, E-mail: gilberto@cphr.edu.cu [Centro de Proteccion e Higiene de las Radiaciones (CPHR), La Habana (Cuba)

    2013-07-01

    The acquisition of know how of practical experiences obtained in the repair and maintenance of readers TLD RADOS for five years of work and the request by the International Atomic Energy for signing new Research Contracts (CRP), made possible the CRP 13328, in which the specialist is committed in the course of a year, to deliver educational software in order to train personnel associated with the operation of the TLD readers RADOS. Due to the importance of continuous transfer of knowledge for new generations of technicians and specialists who join our laboratories, the idea came when the first interactive CD that grouped 19 videos, divided into three blocks was ready: learning, repair and maintenance; it was suggested to expand the training for any TLD reader. Thus a much more complete than the first version package emerged. 7 cases were subsequently published in an IAEA TECDOC, 1599 were included.

  16. RFID based TLD monitoring system - a prospective development

    International Nuclear Information System (INIS)

    Jeevanram, S.S.; Pawar, S.T.; Mahule, K.N.; Rath, D.P.

    2008-01-01

    Thermo Luminescence Dosimetry (TLD) is an established method of monitoring the radiation dose received by workers in radiation environments. In Radiometallurgy Laboratory, BARC, the TLD movement inside a nuclear facility is completely carried out by a radiation worker. However, there is a chance that the TLDs may get lost in laboratories or some places without the knowledge of the concerned TLD user or health physicist. It may later lead to a false effective dose. Effort is being done to initiate a RFID based TLD monitoring system so that the use of TLD can be acknowledged through a self operating software which can prevent misuse of the detector. A novel method of improving the administrative control through Radio Frequency Identification (RFID) based monitoring to avoid such inadvertent misplacement of TLD, is in progress. This paper discusses the method and techniques through which administrative control can be exercised to reduce the number of such in explainable exposures. (author)

  17. Postal TLD audit in radiotherapy in the Czech Republic

    International Nuclear Information System (INIS)

    Kapucianova, M.; Ekendah, D. l.; Bulanek, B.

    2014-01-01

    The postal TLD audit in radiotherapy is an independent check of dose applied by radiotherapy centers. Our poster provides basic information on the methodology of dose determination within the TLD audit. An overview of different versions of the TLD audit that are focused on specific techniques in radiotherapy is given. We also present results of so called basic version of the TLD audit that is performed regularly for purposes of the State Office for Nuclear Safety. Moreover, results of intercomparison measurements organized by the IAEA (International Atomic Energy Agency), in which our laboratory takes part every year, are shown.The methodology of dose determination is based on TL measurement of LiF:Mg,Ti powder. The TL dosemeter (TLD) has form of a plastic capsule containing approximately 160 mg of this material. Before the TL reading, the powder of each particular irradiated dosemeter is divided into 9 identical samples by means of an accurate dispenser. The dosemeter response is given as average of TL responses of the 9 samples. The dose absorbed in water is computed from the TLD response by application of calibration factor and correction coefficients for elimination of energy dependence, supra-linearity and fading of the TL material. The evaluation of the TLD audit is based on comparison of the dose measured by the TLD and the dose stated by a radiotherapy center. Relative deviation between these doses is calculated. Several versions of the TLD audit are available. (authors)

  18. Results and discussion of laboratory experiences with different automated TLD readers for personnel monitoring

    International Nuclear Information System (INIS)

    Regulla, D.F.; Drexeler, G.

    Although the film seems to continue serving as the main personnel dosemeter in Germany for the time in sight, the evolution of particularly solid state techniques and their properties are thoroughly considered with respect to a possible generalized application in personnel monitoring. For this reason different automated TLD systems that are commercially available have been investigated in the laboratory in order to find out their usefulness for a largescale or also decentralized service. Along with studying the dosimetrical and apparative parameters, the question has been discussed to which monitoring philosophy these TLD systems seem to fit. It is reported both on experimental experiences achieved as well as on the results of basic discussions that in return influence the discussion about the necessary outfit of personnel TL dosemeters

  19. A personnel TLD system with person identification

    International Nuclear Information System (INIS)

    Widell, C.O.

    1974-01-01

    The TLD system uses Li 2 B 4 O 7 :Mn, Si sintered tablets which are heated by hot nitrogen. The slide which holds the tablets is coded by a self adhesive polyester-aluminium tape. This tape is BCD coded in an ordinary tape punch. The information on the punched tape includes a ten digit social-security number and a two digit information on location and type of dosimetry. By this system dosimetric data is directly transfered into a central dose register for Sweden. All personnel doses are there stored on social-security numbers. (author)

  20. TLD Quality Assurance (QA) network in radiotherapy and radiology in the Czech Republic

    International Nuclear Information System (INIS)

    Kroutilikova, D.; Novak, N.; Novotny, J.

    2002-01-01

    two years, a total of 50-80 beams are checked annually in this way. If a center shows a deviation outside the acceptance level, it is audited more often. Presently about 90% of these beams comply with the acceptance level. The rest of 10% show deviations up to ±6%, deviations higher than ±6% are very rare nowadays. There are 8 different types of treatment planning systems (TPS) presently used in the Czech Republic. These TPS were tested at 10 radiotherapy centers using the advanced form of the TLD audit. According to multipurpose checks performance, most of the TPS comply with the tolerance level for simple treatment set-ups in case of central beam axis measurements. For off axis measurements some of them exhibit discrepancies above the acceptance level, especially for set-ups with inhomogeneities, oblique incidence and wedges. Two of the tested treatment planning systems showed deviations within the acceptance level of ±3%, another two showed a few deviations up to ±6%, for the rest of systems a few deviations exceeding ±6% were detected. In dental radiology, the audit is aimed to check not only some basic dosimetric characteristics of the X-ray apparatus, but also conditions of film processing process used by dentists. It is well known that dentists often do not keep recommended chemical procedures for film processing. Consequently, they deliver higher exposures to patients in order to speed up the film developing process. For the audit purpose, the dentist receives a dosimetric set with instructions. The dosimetric part of the method includes irradiation of a radiographic film simultaneously with an attached TLD in order to check K a output, irradiation field size and exposure reproducibility. The dentist is instructed to apply usual setting for upper molar exposure. The developing process is checked by means of two dental films and a standardized phantom. The dentist is required to develop an enclosed dental film irradiated under reference conditions in the

  1. Environmental monitoring with TLD in Costa Rica

    International Nuclear Information System (INIS)

    Mora, P.; Mora, E.

    2003-01-01

    Using thermoluminescent dosimeters (Harshaw TLD-200) the first set of costarican data on absorbed doses in air from natural radiation is obtained. During the period from September 1996 to october 2000 eight different sites throughout the country were chosen to instal the TLD stations. Each station had eight cards (five were changed every three months and three changed annually). The dosimeters were read in the Applied Nuclear Physics Laboratory using a 4000 Harshaw reader and with the help a mathematical algorithm and the equipment calibration factors the dose rate in air (nGy h -1 ) was calculated. The national average is 108.9 ± 32.4 nGy h -1 , the lowest values (in nGy h -1 ) were obtain at sea level at Quebrada Honda with 53 ± 11 and the highest values (in nGy h -1 ) at Cartago with 160 ± 19. A slight increase with altitude is observed even though the Cartago station was always the highest. The values found agree with reported worldwide values for environmental doses in air. (Author) [es

  2. Experience of TLD personnel monitoring laboratory

    International Nuclear Information System (INIS)

    Jakhete, Prashant

    2002-01-01

    Full text: Renentech Laboratories is the first Private Enterprise in India to have been chosen to provide Personnel radiation monitoring services to radiation workers at different parts of the country. Since 1992 the Company has been manufacturing TLD phosphor powder of requisite quality and from 1995 commenced the production of TLD cards for radiation monitoring. After getting the necessary approval from the competent authorities in the country, the company undertook a rigorous quality assurance programme and received the accreditation in 1999 to carry out the personnel monitoring of radiation. Since then the trained staff of the Company is covering 1200 institutions in 16 states where radiation is being used. This translates to processing of 60,000 Till cards annually, the maximum limit permitted by BARC. Processing of exposure data is done strictly according well-laid guidelines. Any cases of overexposure are immediately referred to Calibration and Dose Record Section of BARC to meet the regulatory requirements. Necessary procedural guidelines are followed to handle such cases. In this lecture, learning, operation and implementation experience of a typical Private Company in a task, which, hitherto had been regarded as exclusive responsibility of state owned institution, is enumerated

  3. NRC TLD Direct Radiation Monitoring Network

    International Nuclear Information System (INIS)

    Struckmeyer, R.; McNamara, N.

    1992-06-01

    The US Nuclear Regulatory Commission (NRC) Direct Radiation Monitoring Network is operated by the NRC in cooperation with participating states to provide continuous measurement of the ambient radiation levels around licensed NRC facilities, primarily power reactors. Ambient radiation levels result from naturally occurring radionuclides present in the soil, cosmic radiation constantly bombarding the earth from outer space, and the contribution, if any, from the monitored facilities and other man-made sources. The Network is intended to measure radiation levels during routine facility operations and to establish background radiation levels used to assess the radiological impact of an unusual condition, such as an accident. This report presents the radiation levels measured around all facilities in the Network for the first quarter of 1992. All radiation measurements are made using small, passive detectors called thermoluminescent dosimeters (TLDs), which provide a quantitative measurement of the radiation levels in the area in which they are placed. Each site is monitored by arranging approximately 40 to 50 TLD stations in two concentric rings extending to about five miles from the facility. All TLD stations are outside the site boundary of the facility

  4. Robust determination of effective atomic numbers for electron interactions with TLD-100 and TLD-100H thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    Taylor, M.L.

    2011-01-01

    Lithium fluoride thermoluminescent dosimeters (TLD) are the most commonly implemented for clinical dosimetry. The small physical magnitude of TLDs makes them attractive for applications such as small field measurement, in vivo dosimetry and measurement of out-of-field doses to critical structures. The most broadly used TLD is TLD-100 (LiF:Mg,Ti) and, for applications requiring higher sensitivity to low-doses, TLD-100H (LiF:Mg,Cu,P) is frequently employed. The radiological properties of these TLDs are therefore of significant interest. For the first time, in this study effective atomic numbers for radiative, collisional and total electron interaction processes are calculated for TLD-100 and TLD-100H dosimeters over the energy range 1 keV-100 MeV. This is undertaken using a robust, energy-dependent method of calculation rather than typical power-law approximations. The influence of dopant concentrations and unwanted impurities is also investigated. The two TLDs exhibit similar effective atomic numbers, ranging from approximately 5.77-6.51. Differences arising from the different dopants are most pronounced in low-energy radiative effects. The TLDs have atomic numbers approximately 1.48-2.06 times that of water. The effective atomic number of TLD-100H is consistently higher than that of TLD-100 over a broad energy range, due to the greater influence of the higher-Z dopants on the electron interaction cross sections. Typical variation in dopant concentration does not significantly influence the effective atomic number. The influence on TLD-100H is comparatively more pronounced than that on TLD-100. Contrariwise, unwanted hydroxide impurities influence TLD-100 more than TLD-100H. The effective atomic number is a key parameter that influences the radiological properties and energy response of TLDs. Although many properties of these TLDs have been studied rigorously, as yet there has been no investigation of their effective atomic numbers for electron interactions. The

  5. Determination of the TLD-100 physical parameters; Determinacion de parametros fisicos del TLD-100

    Energy Technology Data Exchange (ETDEWEB)

    Paucar J, J.; Picon C, C. [Instituto Nacional de Enfermedades Neoplasicas. INEN. Av. Angamos Este 2520, Lima 34 (Peru)

    1998-12-31

    This study was realized in the Physics service at the Radiotherapy Department of the National Institute of Neoplasic Diseases in Lima, Peru, it was determined the activation energy, the kinetic order and the frequency factor of the fifth peak of the TLD-100 thermoluminescent spectra using different algorithms. This was carried out in parallel with the implementation and design of a software and an interface associated with the Tl lecturer which allows a semiautomatic control for a thermoluminescent lecturer process. (Author)

  6. New advanced TLD system for space dosimetry

    International Nuclear Information System (INIS)

    Feher, I.; Szabo, B.; Vagvoelgyi, J.; Deme, S.; Szabo, P.P.; Csoeke, A.

    1983-10-01

    A new version of the TLD reader type PILLE has been developed for space applications. The earlier compact and portable device could also be used for measurements during space flights but its range was limited. A new bulb detector with easier handling has also been developed with an upper limit of linear dose response of 10 Gy. The range of this new and more versatile reader, NA206S, (1μGy-10 Gy) is 3 orders of magnitude higher than that of the earlier system; it also has increased sensitivity and decreased mass. It can be used not only in space applications but also for environmental monitoring or even in accident dosimetry. The measured dose value is displayed on a four-digit display with automatic range switch. Another new version, the NA206E, has been developed for environmental dosimetry; it can be operated from a battery or from the mains. (author)

  7. The IAEA/WHO TLD postal programme for radiotherapy hospitals

    International Nuclear Information System (INIS)

    Izewska, J.; Andreo, P.

    2000-01-01

    Since 1969 the International Atomic Energy Agency (IAEA), together with the World Health Organization (WHO), has performed postal TLD audits to verify the calibration of radiotherapy beams in developing countries. A number of changes have recently been implemented to improve the efficiency of the IAEA/WHO TLD programme. The IAEA has increased the number of participants and reduced significantly the total turn-around time to provide results to the hospitals within the shortest possible time following the TLD irradiations. The IAEA has established a regular follow-up programme for hospitals with results outside acceptance limits of ±5%. The IAEA has, over 30 years, verified the calibration of more than 3300 clinical photon beams at approximately 1000 radiotherapy hospitals. Only 65% of those hospitals who receive TLDs for the first time have results within the acceptance limits, while more than 80% of the users that have benefited from a previous TLD audit are successful. The experience of the IAEA in TLD audits has been transferred to the national level. The IAEA offers a standardized TLD methodology, provides Guidelines and gives technical back-up to the national TLD networks. The unsatisfactory status of the dosimetry for radiotherapy, as noted in the past, is gradually improving however, the dosimetry practices in many hospitals in developing countries need to be revised in order to reach adequate conformity to hospitals that perform modern radiotherapy in Europe, USA and Australia. (author)

  8. X-rays individual dose assessment using TLD dosimeters

    International Nuclear Information System (INIS)

    Salas, Carlos

    2008-01-01

    This paper describes the methodology used in Embalse NPP for measuring individual X-ray dose in dentists and radiologists, who work in areas near the plant. Personnel is provided with TLD personal dosimeters for thoracic use, as well as TLD ring dosimeters. This individual X-ray dosimetry is fundamental in order to know the effective energy coming from the radiation field, since the dosimetry factors depend on it. On the other hand, the response of the TLD crystals also depends of the effective energy; this accentuates the problem when assessing the individual dose. The X-ray dosimeter must simultaneously determine the value of the effective energy and the corresponding dose value. The basic principle for determining effective energy is by using at least two different TLD materials covered by filters of different thickness. The TLD materials used have totally energy responses. Therefore, different readouts from each of the crystals are obtained. The ratio between both readouts provides a factor that depends of the effective energy but that is 'independent' from the exposure values irradiated to the dosimeter. The Personal TLD dosimeter currently in use is Bicron-Harshaw. It comprises a carrier model 8807. This carrier contains a card model 2211 which groups two TLD 200 crystals and two TLD 100 crystals. It has internal filters at each side of the TLD 200 crystals. The periodical calibration of these dosimeters consists in the irradiation of some dosimeters with different X-ray energy beams in the National Atomic Energy Commission (CNEA). This dosimeter was used, by the National Regulatory Authority (ARN) in several comparisons, always getting satisfactory results. (author)

  9. TLD audit in radiotherapy in the Czech Republic

    International Nuclear Information System (INIS)

    Kroutilikova, D.; Zackova, H.; Judas, L.

    1998-01-01

    National Radiation Protection Institute in Prague organizes the TLD audit. The aim of the TLD postal audit is to provide control of the clinical dosimetry in the Czech Republic for purposes of state supervision in radiotherapy, to investigate and to reduce uncertainties involved in the measurements of absorbed dose and to improve consistency in dose determination in the regional radiotherapy centers. TLD audit covers absorbed dose measurements under reference conditions for 60 Co and 137 Cs beams, high-energy X-ray and electron beams of of linear accelerators and betatrons. The thermo-luminescence dosemeters are sent regularly to all radiotherapy centers. Absorbed dose measures by the TLD is compared to absorbed dose stated by radiotherapy center. Encapsulated LiF:Mg, Ti powder is used for the measurement. Deviation of 3% between stated and TLD measured dose is considered for photons and ±5% for electron beams. First TLD audit was started in 1997. A total of 135 beams was checked. There were found seven major deviations (more than ±6%), which were very carefully investigated. Medical Physicists from these departments reported a set-up mistake. However, at most of those hospitals with major deviations, an in situ audit in details was made soon after TLD audit. There were found discrepancies of clinical dosimetry but also bad technical state of some of the irradiation units. In 1998, second course TLD audit was started. No major deviation was found. Regular TLD audit seems to be a good way to eliminate big mistakes in the basic clinical dosimetry. Repeated audit in the regional radiotherapy centers that had major deviation during the first audit exhibited improvement of their dosimetry. It is intended to broaden the method and to control also beam parameters by means of a multi-purpose phantom. (authors)

  10. Measurement of annual dose on porcelain using surface TLD method

    International Nuclear Information System (INIS)

    Xia Junding; Wang Weida; Leung, P.L.

    2001-01-01

    In order to improve accuracy of TL authentication test for porcelain, a method of measurement of annual dose using ultrathin (CaSO 4 :Tm) dosage layer on porcelain was studied. The TLD was placed on the part of porcelain without glaze. A comparison of measurement of annual dose for surface TLD, inside TLD and alpha counting on porcelain was made. The results show that this technique is suitable for measuring annual dose and improving accuracy of TL authentication test for both porcelain and pottery

  11. Thermoluminescent dosimeters (TLD) quality assurance network in the Czech Republic.

    Science.gov (United States)

    Kroutilķková, Daniela; Novotný, Josef; Judas, Libor

    2003-02-01

    The Czech thermoluminescent dosimeters (TLD) quality assurance network was established in 1997. Its aim is to pursue a regular independent quality audit in Czech radiotherapy centres and to support state supervision. The audit is realised via mailed TL dosimetry. The TLD system consists of encapsulated LiF:Mg,Ti powder (type MT-N) read with Harshaw manual reader model 4000. Basic mode of the TLD audit covers measurements under reference conditions, specifically beam calibration checks for all clinically used photon and electron beams. Advanced mode consists of measurements under both reference and non-reference conditions using a solid multipurpose phantom ('Leuven phantom') for photon beams. The radiotherapy centres are instructed to deliver to the TLD on central beam axis absorbed dose of 2 Gy calculated with their treatment planning system for a particular treatment set-up. The TLD measured doses are compared with the calculated ones. Deviations of +/-3% are considered acceptable for both basic and advanced mode of the audit. There are 34 radiotherapy centres in the Czech Republic. They undergo the basic mode of the TLD audit regularly every 2 years. If a centre shows a deviation outside the acceptance level, it is audited more often. Presently, most of the checked beams comply with the acceptance level. The advanced TLD audit has been implemented as a pilot study for the present. The results were mostly within the acceptance limit for the measurements on-axis, whereas for off-axis points they fell beyond the limit more frequently, especially for set-ups with inhomogeneities, oblique incidence and wedges. The results prove the importance of the national TLD quality assurance network. It has contributed to the improvement of clinical dosimetry in the Czech Republic. In addition, it helps the regulatory authority to monitor effectively and regularly radiotherapy centres.

  12. Thermoluminescent dosimeters (TLD) quality assurance network in the Czech Republic

    International Nuclear Information System (INIS)

    Kroutilikova, Daniela; Novotny, Josef; Judas, Libor

    2003-01-01

    Introduction: The Czech thermoluminescent dosimeters (TLD) quality assurance network was established in 1997. Its aim is to pursue a regular independent quality audit in Czech radiotherapy centres and to support state supervision. Materials and methods: The audit is realised via mailed TL dosimetry. The TLD system consists of encapsulated LiF:Mg,Ti powder (type MT-N) read with Harshaw manual reader model 4000. Basic mode of the TLD audit covers measurements under reference conditions, specifically beam calibration checks for all clinically used photon and electron beams. Advanced mode consists of measurements under both reference and non-reference conditions using a solid multipurpose phantom ('Leuven phantom') for photon beams. The radiotherapy centres are instructed to deliver to the TLD on central beam axis absorbed dose of 2 Gy calculated with their treatment planning system for a particular treatment set-up. The TLD measured doses are compared with the calculated ones. Deviations of ±3% are considered acceptable for both basic and advanced mode of the audit. Results: There are 34 radiotherapy centres in the Czech Republic. They undergo the basic mode of the TLD audit regularly every 2 years. If a centre shows a deviation outside the acceptance level, it is audited more often. Presently, most of the checked beams comply with the acceptance level. The advanced TLD audit has been implemented as a pilot study for the present. The results were mostly within the acceptance limit for the measurements on-axis, whereas for off-axis points they fell beyond the limit more frequently, especially for set-ups with inhomogeneities, oblique incidence and wedges. Conclusions: The results prove the importance of the national TLD quality assurance network. It has contributed to the improvement of clinical dosimetry in the Czech Republic. In addition, it helps the regulatory authority to monitor effectively and regularly radiotherapy centres

  13. Dosimetric characteristics of a TLD dosemeter with extremities; Caracteristicas dosimetricas de un dosimetro TLD de extremidades

    Energy Technology Data Exchange (ETDEWEB)

    Molina P, D.; Diaz B, E.; Lien V, R. [Centro de Proteccion e Higiene de las Radiaciones, CPHR, Apdo.Postal 6195, Habana 6, CP 10600, Ciudad Habana (Cuba)

    1999-07-01

    It was designed a TLD dosemeter for the monitoring of the extremities. This one consists in a metallic ring with a circular orifice where is arranged a T L detector of LiF: Mg,Ti (Model JR1152C) 5 x 5 x 0.8 mm{sup 3} covered by a polyethylene fine layer. In this work were studied the dosimetric properties of the dosemeter for its application in the dosimetry of extremities for photonic radiation. the results obtained allow conclude that the designed dosemeter can be used for the extremities monitoring. (Author)

  14. Estimation of uncertainty in TLD calibration

    International Nuclear Information System (INIS)

    Hasabelrasoul, H. A.

    2013-07-01

    In this study thermoluminescence dosimeter TLD was use of individual control devices to make sure the quality assurance and quality control in individual monitoring. The uncertainty measured in reader calibration coefficients for tow reader and uncertainty in radiation dose after irradiate in SSDL laboratory. Fifty sample was selected for the study was placed in the oven at a temperature of 400 for an hour to get zero or background and took zero count by or background and took zero count by reader (1) and reader (2) and then irradiate in SSDL by cesium-137 at a dose of 5 mGy and laid back in the oven at degrees 100 and degrees 10 minutes, to 10 chips for calibration and readout count by reader one and reader two. The RCF was found for each reader above 1.47 and 1.11, respectively, and found the uncertainty RCF was found for each reader above 1.47 and 1.11, respectively, and found the uncertainly RCF 0.430629 and 0.431973. Radiation dose was measured for fifty samples irradiate to dose of 5 mGy and read the count by reader 1 and reader 2 the uncertainty was found for each reader 0.490446 and 0.587602.(Author)

  15. Comparison of LiF (TLD-100 and TLD-100H) detectors for extremity monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Freire, L. [Departamento de Proteccao Radiologica e Seguranca Nuclear, Instituto Tecnologico e Nuclear, E.N. 10, 2683-953 Sacavem (Portugal); Laboratorio de Medicina Nuclear, Lda, Atomedical, Rua Helena Felix, 11D, 1600-121 Lisboa (Portugal); Calado, A.; Cardoso, J.V.; Santos, L.M. [Departamento de Proteccao Radiologica e Seguranca Nuclear, Instituto Tecnologico e Nuclear, E.N. 10, 2683-953 Sacavem (Portugal); Alves, J.G. [Departamento de Proteccao Radiologica e Seguranca Nuclear, Instituto Tecnologico e Nuclear, E.N. 10, 2683-953 Sacavem (Portugal)], E-mail: jgalves@itn.pt

    2008-02-15

    In this work the results aimed at assessing the performance of two types of LiF detectors, TLD-100 and TLD-100H, used in the context of extremity dosimetry are presented. Each detector variety was studied for reproducibility, batch homogeneity, residual dose, linearity and energy dependence using, when appropriate, the {sup 90}Sr/{sup 90}Y radiation source built-in one of the Harshaw 6600 readers, the ISO narrow X-ray beams of N30, N40, N60, N80, N100 and N120 or the gamma radiations of {sup 137}Cs and {sup 60}Co. Two calibration energies (N120 and {sup 137}Cs) were also used. The reproducibility and linearity results indicate that both LiF:Mg,Ti and LiF:Mg,Cu,P performed equally well. However, LiF:Mg,Cu,P presents a higher residual signal. In terms of energy dependence, LiF:Mg,Cu,P shows less variation than LiF:Mg,Ti particularly when N120 is used as calibration radiation. This seems to be a more realistic setup since the energy of the most frequently used radioisotopes in Nuclear Medicine departments with single photon emission computed tomography (SPECT) use gamma radiation energies closer to N120 than to {sup 137}Cs.

  16. Quality control in medical radiology using T.L.D

    International Nuclear Information System (INIS)

    Rolemberg Silva, F.A.; Nascimento Souza, D. do

    2006-01-01

    In this work tests of quality control in beams of X rays have been carried out, at diagnostic level, of two radiological services equipments of Brazilian hospitals (Aracaju, SE). We obtained the air kerma and kerma rate values, the beams efficiency, the coherence between the luminous fields and the referring fields of irradiation and half-value layer to each equipment and set of parameters. The measures of direct form have been obtained using two ionization chambers, one cylindrical and another one with parallel plates. An optional method for accomplishment some of the tests were carried out with CaSO 4 :Dy + Teflon thermoluminescent dosimeters. The values of air kerma were evaluated for three tube voltage, 40, 60 and 81 kV at 1.0 m from the focus of the equipments. For each one of the voltages three distinct current values were chosen besides a fixed value of exposition time. The results showed that the values of air kerma varied between 8.0 μGy and 0.35 μGy. The T.L.D. have revealed useful for the measures if the response to the dose is previously known for each set of beam parameters used for the irradiations. Otherwise, the tests with the dosimeters can serve to evaluate the beams conditions and their reproducibility. The evaluation results of coherence between the luminous fields and the irradiation fields demonstrated that the difference between the radiation and the luminous fields did not exceed 2% of the distance between the focal point and the film. We found satisfactory values for half-value layer. (author)

  17. Measurement of TLD Albedo response on various calibration phantoms

    International Nuclear Information System (INIS)

    Momose, T.; Tsujimura, N.; Shinohara, K.; Ishiguro, H.; Nakamura, T.

    1996-01-01

    The International Commission on Radiation Units and Measurements (ICRU) has recommended that individual dosemeter should be calibrated on a suitable phantom and has pointed out that the calibration factor of a neutron dosemeter is strongly influenced by the the exact size and shape of the body and the phantom to which the dosemeter is attached. As the principle of an albedo type thermoluminescent personal dosemeter (albedo TLD) is essentially based on a detection of scattered and moderated neutron from a human body, the sensitivity of albedo TLD is strongly influenced by the incident neutron energy and the calibration phantom. (1) Therefore for albedo type thermoluminescent personal dosemeter (albedo TLD), the information of neutron albedo response on the calibration phantom is important for appropriate dose estimation. In order to investigate the effect of phantom type on the reading of the albedo TLD, measurement of the TLD energy response and angular response on some typical calibration phantoms was performed using dynamitron accelerator and 252 Cf neutron source. (author)

  18. How to diagnose any type of TLD Reader?

    International Nuclear Information System (INIS)

    Rodriguez, Manuel Lopez; Garcia, Jose A. Tamayo; Gil, Alex Vergara; Lores, Stefan Gutierrez; Acosta, Andry Romero; Villanueva, Gilberto Alonso

    2013-01-01

    The acquisition of know how of practical experiences obtained in the repair and maintenance of readers TLD RADOS for five years of work and the request by the International Atomic Energy for signing new Research Contracts (CRP), made possible the CRP 13328, in which the specialist is committed in the course of a year, to deliver educational software in order to train personnel associated with the operation of the TLD readers RADOS. Due to the importance of continuous transfer of knowledge for new generations of technicians and specialists who join our laboratories, the idea came when the first interactive CD that grouped 19 videos, divided into three blocks was ready: learning, repair and maintenance; it was suggested to expand the training for any TLD reader. Thus a much more complete than the first version package emerged. 7 cases were subsequently published in an IAEA TECDOC, 1599 were included

  19. Positional glow curve simulation for thermoluminescent detector (TLD) system design

    International Nuclear Information System (INIS)

    Branch, C.J.; Kearfott, K.J.

    1999-01-01

    Multi- and thin element dosimeters, variable heating rate schemes, and glow-curve analysis have been employed to improve environmental and personnel dosimetry using thermoluminescent detectors (TLDs). Detailed analysis of the effects of errors and optimization of techniques would be highly desirable. However, an understanding of the relationship between TL light production, light attenuation, and precise heating schemes is made difficult because of experimental challenges involved in measuring positional TL light production and temperature variations as a function of time. This work reports the development of a general-purpose computer code, thermoluminescent detector simulator, TLD-SIM, to simulate the heating of any TLD type using a variety of conventional and experimental heating methods including pulsed focused or unfocused lasers with Gaussian or uniform cross sections, planchet, hot gas, hot finger, optical, infrared, or electrical heating. TLD-SIM has been used to study the impact on the TL light production of varying the input parameters which include: detector composition, heat capacity, heat conductivity, physical size, and density; trapped electron density, the frequency factor of oscillation of electrons in the traps, and trap-conduction band potential energy difference; heating scheme source terms and heat transfer boundary conditions; and TL light scatter and attenuation coefficients. Temperature profiles and glow curves as a function of position time, as well as the corresponding temporally and/or spatially integrated glow values, may be plotted while varying any of the input parameters. Examples illustrating TLD system functions, including glow curve variability, will be presented. The flexible capabilities of TLD-SIM promises to enable improved TLD system design

  20. Study of physical factors affecting the TLD readout

    International Nuclear Information System (INIS)

    Ahmed, Amira Abd Elrhman Ebrahim

    2015-10-01

    The aim of the study was to study the effects of physical factors in TLD reading. The dosimeters have been irradiated with x rays of (0.5 mGy to 5 mGy) using plastic holder with Aluminum filters with dimensions 1.5 x 0.8 mm and 0.5 mm in thickness to obtain the equivalent dose Hp (10) flux of nitrogen gas and annealing after data collection by TLD Reader Analyzer 04 (Version 0.9.400 micro lab (krakow 2012). The count and dose analysis shows that; The count/s given by TLD appears to be higher in case of using filtration which was 7189.9 eps in contrast with reading without filter which was 4055.8 eps. There was proportional linear relationship between the applied dose and the TLD count for both cases with and without filter. And the correlation could be fitted in the form of equations: y=423.9 x + 1023 and y = 432.5 x + 405.3 for filtered and y refers to count/s. Such increment in count is ascribed to increasing applied radiation dose as well it indicates and confirms the linearity of TLD in measuring the radiation dose since R 2 = 0.9. However the count with filter for the applied radiation dose in mGy was greater than that without filter. The that measured with pellets annealing (reading of zero doses). TLD pellets reading without zero dose measurement usually gives greater dose ( 441.8 and 563.6 μGy) relative to the case where the zero doses have been measured which were 289.6 and 429.2 μGy, respectively. While the effect of using filtration is so obvious and leads to increase of zero dose, respectively relative to dose s of un reading of zero dose, and reading of zero dose, but without filter.(Author)

  1. Direct measurement of annual β dose using TLD on porcelain

    International Nuclear Information System (INIS)

    Leung, P.L.; Stokes, M.J.; Xia Junding; Wang Weida; Zhou Zhixin

    1999-01-01

    In order to improve accuracy of TL authentication test for porcelain, a method of direct measurement of annual β dose using ultrathin TLD (CaSO 4 :Tm) on porcelain was studied. Since the TLD was placed into a hole left after sampling for the TL measurement, the method will not cause any new damage to the studied object. The results show that the technique is suitable for measuring annual β dose and improving accuracy of TL authentication test for both porcelain and pottery

  2. Differences in TLD 600 and TLD 700 glow curves derived from distict mixed gamma/neutron field irradiations

    International Nuclear Information System (INIS)

    Cavalieri, Tassio A.; Castro, Vinicius A.; Siqueira, Paulo T.D.

    2013-01-01

    In Neutron Capture Therapy, a thermal neutron beam shall impinge on a specific nuclide, such as 10 B, to promote a nuclear reaction which releases the useful therapeutic energy. A nuclear reactor is usually used as the neutron source, and therefore field contaminants such as gamma and high energy neutrons are also present in the field. However, mixed field dosimetry still stands as a challenge in some cases, due to the difficulty to experimentally discriminate the dose from each field component. For the mixed field dosimetry, the International Commission on Radiation end Units (ICRU) recommends the use of detector pairs with different responses for each beam component. The TLD 600/700 pair meets this need, because these LiF detectors have different Li isotopes concentration, with distinct thermal neutron responses because 6 Li presents a much higher neutron capture cross section than does 7 Li for low energy neutrons. TLD 600 is 6 Li enriched while TLD 700 is 7 Li enriched. However, depending on the neutron spectrum presented in the mixed field, TLD 700 response to thermal neutrons cannot be disregarded. This work aims to study the difference in TLD 600 and TLD 700 glow curves when these TLDs are submitted to mixed fields of different energy spectra and components balance. The TLDs were irradiated in a pure gamma source, and in mixed fields from an AmBe sealed source and from the IPEN/MB-01 reactor. These TLDs were read and had their two main dosimetric regions analyzed to observe the differences in the glow curves of these TLDs in each irradiation. Field components discrimination was achieved through Monte Carlo simulations run with MCNP radiation transport code. (author)

  3. Towards an automated TLD system that meets international requirements

    International Nuclear Information System (INIS)

    Boetter-Jensen, L.; Vanamo, V.

    1988-01-01

    The new recently introduced fully automated TLD system developed by Alnor OY on the basis of the Riso prototype, is intended to meet draft IEC/ISO proposals and ANSI requirements. Part of the system is a personal dosemeter badge and an environmental dosemeter package following ICRU recommendations. The overall system consists of a software-controlled automated reader, a programable irradiator/calibrator, a computer, and dosemeters for environmental, whole body, extremity and clinical applications. The personal TLD badge that contains four TLD pellets is designed to agree with ICRU H p (10) and H s (0.07) quantities for determining dose equivalent. The badge can accommodate a large variety of the most commonly used solid TL dosemeter products. A special effort was put into the evaluation of skin dose by considering the use of graphite-mixed hot-sintered LiF pellets. The TLD system is described and results from a performance test that comprised measurements of photon energy response, angular dependence, and reproducibility are presented

  4. Periodicity of TLD badge personnel monitoring service in India

    International Nuclear Information System (INIS)

    Kher, R.K.; Joshi, V.D.; Kaushik, Aruna; Sharma, Amiy; Chatterjee, S.

    2003-01-01

    The periodicity of an individual monitoring service is an important aspect. Presently minimum period for TLD badge service is maintained as 'calendar month' and choice of quarterly service is also offered. The periodicity of the TLD service for a given category/application type of institution, is to be fixed taking into account level of average occupational doses in all or typical institutions of given category and other information indicating the status of safety and possible fluctuations of exposure levels and potential for overexposure cases. This paper presents the status on the periodicity of TLD Badge Service as is evolved and adopted for the four broad categories i.e. DAE (Nuclear Fuel Cycle) Institutions, Industrial, Medical, Research institutions. It is concluded that quarterly service is a convenient option for institution categories where type of work/workload, and work practices are such that occupational exposures could be normally kept below about one mSv or so in the monitoring period, average annual dose less than 1 mSv and persons receiving annual dose >10 mSv is less than 1% of total in the category. Also, the judicious use of the flexibility in the periodicity of TLD Badge service would help (i) to keep the monitoring related workload to the optimum for the monitoring units and (ii) to keep the expenses incurred by the institution towards monitoring to the minimum without sacrificing radiation safety (iii) to focus the extra monitoring efforts on the applications/situations requiring improvement in radiation safety. (author)

  5. Environmental dose measurement with microprocessor based portable TLD reader

    International Nuclear Information System (INIS)

    Deme, S.; Apathy, I.; Feher, I.

    1996-01-01

    Application of TL method for environmental gamma-radiation dosimetry involves uncertainty caused by the dose collected during the transport from the point of annealing to the place of exposure and back to the place of evaluation. Should an accident occur read out is delayed due to the need to transport to a laboratory equipped with a TLD reader. A portable reader capable of reading out the TL dosemeter at the place of exposure ('in situ TLD reader') eliminates the above mentioned disadvantages. We have developed a microprocessor based portable TLD reader for monitoring environmental gamma-radiation doses and for on board reading out of doses on space stations. The first version of our portable, battery operated reader (named Pille - 'butterfly') was made at the beginning of the 80s. These devices used CaSO 4 bulb dosemeters and the evaluation technique was based on analogue timing circuits and analogue to digital conversion of the photomultiplier current with a read out precision of 1 μGy and a measuring range up to 10 Gy. The measured values were displayed and manually recorded. The version with an external power supply was used for space dosimetry as an onboard TLD reader

  6. Introducing 2D barcode on TLD cards - a step towards automation in personnel monitoring

    International Nuclear Information System (INIS)

    Ajoy, K.C.; Dhanasekaran, A.; Annalakshmi, O; Rajagopal, V.; Santhanam, R.; Jose, M.T.

    2018-01-01

    As part of personnel monitoring services, TLD lab, RSD, IGCAR issues and receives large numbers of TLD cards every month, for use by occupational workers belonging to various hot facilities at Kalpakkam. Considering the nature of the work being manual, routine, labour intensive and being prone for human errors, introducing automation would be necessary at the TLD lab as well as at the user facility. This requires identification of the individual components of the TLD and embed them with unique identification for the system to accomplish the task. The paper discusses the automation part related to the TLD cards

  7. Dosimetric quality control in radiotherapy using TLD methodology

    International Nuclear Information System (INIS)

    Saravi, M.C.; Kessler, C.; Alvarez, P.E.; Feld, D.B.

    2002-01-01

    In the frame of the IAEA Co-ordinated Research Project 'Development of a Quality Assurance Program for Radiation Therapy Dosimetry in Developing Countries' a Dosimetric Quality Control Group was set up in Argentina in 1996, to develop a program in order to improve radiotherapy in the country. Nowadays, this Group, briefly called External Audit Group (EAG), is composed by the national Secondary Standard Dosimetry Laboratory (SSDL), which has the responsibility for dose determinations, traceability to international dosimetry chain and TLD measurements, and two Medical Physicists from CNEA who are working at the Oncology Hospital 'Marie Curie' in Buenos Aires. The present paper reports the activities performed by the EAG with external high energy photon beams in reference conditions and the results of two pilot studies on cobalt 60 beams in non-reference conditions. The first step of the program was to update the existing data base about the radiotherapy centres operating in the country. A form was sent to each of them in order to obtain basic information about their staff, number and type of treatment machines, brachytherapy sources, measuring devices, beam calibration, treatment planning system, simulator and other relevant data. 90 radiotherapy centres were registered in the EAG data base. Forms were completed by 75/90 centres. There are nowadays 69 cobalt 60 units and 42 LINACs operating in the country (18/42 LINACs producing high energy X ray and electron beams). EAG deals with measurements performed with mailed TLD irradiated at radiotherapy centres. Internal quality control on our TLD system is made during each audit by means of reference capsules irradiated by IAEA; external controls consist in blind tests performed by IAEA once a year. The correction factor, K en , determined at our SSDL for high energy X-rays was checked with the collaboration of IAEA and Prague National Radiation Protection Institute (PNRPI) by means of a blind test. Results for 4 MV, 6 MV

  8. Environmental monitoring system with TLD; Sistema de monitoreo ambiental con TLD

    Energy Technology Data Exchange (ETDEWEB)

    Aguerre, L.; Carelli, J.; Gregori, B. [Autoridad Regulatoria Nuclear Argentina (Argentina)]. e-mail: laguerre@cae.arn.gov.ar

    2006-07-01

    Presently work the methodology used by the Laboratory of Thermoluminescent Dosimetry (TLD) of the Nuclear Regulatory Authority (RNA) to gauge it system of environmental monitoring in function of the media absorbed dose rate in free air and the environmental dose equivalent, H{sup *}(10), according to the recommendation ICRU Report 47 is described. It was studied the response of the environmental dosemeter (DA) in fields of photonic radiation of energies W60, Wl 10, W200 and {sup 137} Cs. The irradiations were carried out following the recommendations of the standard ISO:4037. It was analyzed the response in the DA of the detectors LiF: Mg, Ti and CaF{sub 2}: Dy for the different radiation qualities and the relative response at {sup 137} Cs of both. The methodology used in the evaluation of the dose includes: the correction of the readings of both detectors by fading, gotten experimentally, the witness of transfers, the energy answer and the value of the zero. The dose is calculated applying the average pondered in uncertainty of the dose obtained for each type of detector. Its were analyzed and calculated the uncertainties that affect to the measurement following the recommendation of the Argentine standard IRAM 35050. The detection limit of the absorbed dose rate in free air of this system it is 3.5 n Gy/h for a period of sampling of 3 months. With this detection limit environmental dose equivalent rates of the order of 70 n Sv/h are measured with an expanded uncertainty of the order of 10% with a cover factor k = 2. (Author)

  9. Photon energy response of an aluminum oxide TLD environmental dosimeter

    International Nuclear Information System (INIS)

    Olsher, R.H.

    1992-01-01

    Because of aluminum oxide's significant advantage in sensitivity (about a factor of 30) over LiF, minimal fading characteristics and ease of processing, aluminum oxide thermoluminescent dosimeters (TLDS) are being phased in at Los alamos for environmental monitoring of photon radiation. The new environmental dosimeter design consists of a polyethylene holder, about 0. 5 cm thick, loaded with a stack of four aluminum oxide TLD chips, each 1 mm thick and 5 mm in diameter. As part of the initial evaluation of the new design, the photon energy response of the dosimeter was calculated over the range from 10 keV to 1 MeV. Specific goals of the analysis included the determination of individual chip response in the stack, assessment of the response variation due to TLD material (i.e., LiF versus A1 2 O 3 ), and the effect of copper filtration in flattening the response

  10. Quality Assurance and Quality Control in TLD Measurement

    International Nuclear Information System (INIS)

    Bhuiyan, S.I.; Qronfla, M.M.; Abulfaraj, W.H.; Kinsara, A.A.; Taha, T.M.; Molla, N.I.; Elmohr, S.M.

    2008-01-01

    TLD technique characterized by high precision and reproducibility of dose measurement is presented by addressing pre-readout annealing, group sorting, dose evaluation, blind tests, internal dose quality audit and external quality control audits. Two hundred and forty TLD chips were annealed for 1 hour at 4000 degree C followed by 2 h at 1000 degree C. After exposure of 1 mGy from 90 Sr irradiator TLDs were subjected to pre-readout annealing at 1000 degree C, then readout, sorted into groups each with nearly equal sensitivity. Upon repeating the procedures, TLDs having response >3.5% from group mean were dropped to assuring group stability. Effect of pre-readout annealing has been studied. Series of repeated measurements were conducted to stabilize calibration procedures and DCF generation using SSDL level 137 Cs calibrator, dose master, ionization chambers. Performed internal dose quality audits, blind tests and validated by external QC tests with King Abdulaziz City of Science and Technology

  11. Environmental radiation measurements using TLD in and around AERE, Dhaka

    International Nuclear Information System (INIS)

    Mollah, A.S.; Husain, S.R.; Rahman, M.M.

    1986-01-01

    The external background radiation level in and around the Atomic Energy Research Establishment (AERE) in Dhaka has been measured. The measurements were performed using lithium fluoride (LiF) thermoluminescence dosemeters (TLD-100) at 32 locations, all one metre above the ground. The annual average dose rate measured in the AERE environs was 1.74+-0.23 mGy.y -1 in air, based on analysis of thermoluminescence dosemeter data collected from 1982 to 1984. (author)

  12. Meeting regulatory standards with BeO ceramic TLD

    International Nuclear Information System (INIS)

    Gammage, R.B.; Christian, D.J.

    1978-01-01

    Measurements of exposures below 1 mR are possible with BeO ceramic TLD by signal recording that discriminates against an interfering pyroelectric incandescence. Performance under environmental monitoring conditions is considered in light of current regulatory criteria. Factors such as reproducibility and batch uniformity are satisfactory. An anomalous energy dependence causes an over-response that will probably require use of an energy compensation shield

  13. Indoor gamma radiation monitoring In Rawalpindi, Pakistan using TLD100

    International Nuclear Information System (INIS)

    Azam, Sana; Tufail, Muhammad; Sohail, Muhammad

    2008-01-01

    Full text: Natural radioactivity originates from extraterrestrial sources as well as from radioactive elements in earth's crust. The amount of radioactivity varies from place to place and with altitude. The aim of this study was to observe the indoor radiation level in Rawalpindi using TLD. For this purpose LiF:Mg:Ti (TLD100) chips were used. Chips were annealed and then calibrated using different sources and the calibration factor obtained by using Cs137 source was selected for dose estimation. Its value was 0.1403 μGy/TL response. Rawalpindi categorized into six regions. In each region, 5 cemented houses were selected and TLD 100 chips were placed at a distance of 0.5 m from ground the level. Chips were properly covered to protect them from ultraviolet light and moisture and were placed for three months. The average annual indoor dose rate for Rawalpindi was estimated to be 392.105μGy/yr and average dose to be 97.65μGy. Therefore, the effective dose for population of Rawalpindi from indoor gamma radiation was estimated to be 313.68μSv/yr using an indoor occupancy factor of 80%. (author)

  14. Self-shielding factors for TLD-600 and TLD-100 in an isotropic flux of thermal neutrons

    International Nuclear Information System (INIS)

    Horowitz, Y.S.; Dubi, A.; Ben Shahar, B.

    1976-01-01

    The applications of lithium fluoride thermoluminescent dosemeters in mixed n-γ environments, and the dependence of LiF-TL on linear energy transfer are both topics of current interest. Monte Carlo calculations have therefore been carried out to determine the thermal neutron absorption probability (and consequently the self-shielding factor) for an isotropic flux of neutrons impinging on different sized cylindrical samples of LiF TLD-100 and TLD-600. The calculations were performed for cylinders of radius up to 10 cm and heights of 0.1 to 1.5 cm. The Monte Carlo results were found to be significantly different from the analytic calculations for infinitely long cylinders, but, as expected, converged to the same value for (r/h) << 1. (U.K.)

  15. Neutron dose measurements of Varian and Elekta linacs by TLD600 and TLD700 dosimeters and comparison with MCNP calculations.

    Science.gov (United States)

    Nedaie, Hassan Ali; Darestani, Hoda; Banaee, Nooshin; Shagholi, Negin; Mohammadi, Kheirollah; Shahvar, Arjang; Bayat, Esmaeel

    2014-01-01

    High-energy linacs produce secondary particles such as neutrons (photoneutron production). The neutrons have the important role during treatment with high energy photons in terms of protection and dose escalation. In this work, neutron dose equivalents of 18 MV Varian and Elekta accelerators are measured by thermoluminescent dosimeter (TLD) 600 and TLD700 detectors and compared with the Monte Carlo calculations. For neutron and photon dose discrimination, first TLDs were calibrated separately by gamma and neutron doses. Gamma calibration was carried out in two procedures; by standard 60Co source and by 18 MV linac photon beam. For neutron calibration by (241)Am-Be source, irradiations were performed in several different time intervals. The Varian and Elekta linac heads and the phantom were simulated by the MCNPX code (v. 2.5). Neutron dose equivalent was calculated in the central axis, on the phantom surface and depths of 1, 2, 3.3, 4, 5, and 6 cm. The maximum photoneutron dose equivalents which calculated by the MCNPX code were 7.06 and 2.37 mSv.Gy(-1) for Varian and Elekta accelerators, respectively, in comparison with 50 and 44 mSv.Gy(-1) achieved by TLDs. All the results showed more photoneutron production in Varian accelerator compared to Elekta. According to the results, it seems that TLD600 and TLD700 pairs are not suitable dosimeters for neutron dosimetry inside the linac field due to high photon flux, while MCNPX code is an appropriate alternative for studying photoneutron production.

  16. Developmental roles of the BMP1/TLD metalloproteinases.

    Science.gov (United States)

    Ge, Gaoxiang; Greenspan, Daniel S

    2006-03-01

    The astacin family (M12A) of the metzincin subclan MA(M) of metalloproteinases has been detected in developing and mature individuals of species that range from hydra to humans. Functions of this family of metalloproteinase vary from digestive degradation of polypeptides, to biosynthetic processing of extracellular proteins, to activation of growth factors. This review will focus on a small subgroup of the astacin family; the bone morphogenetic protein 1 (BMP1)/Tolloid (TLD)-like metalloproteinases. In vertebrates, the BMP1/TLD-like metalloproteinases play key roles in regulating formation of the extracellular matrix (ECM) via biosynthetic processing of various precursor proteins into mature functional enzymes, structural proteins, and proteins involved in initiating mineralization of the ECM of hard tissues. Roles in ECM formation include: processing of the C-propeptides of procollagens types I-III, to yield the major fibrous components of vertebrate ECM; proteolytic activation of the enzyme lysyl oxidase, necessary to formation of covalent cross-links in collagen and elastic fibers; processing of NH2-terminal globular domains and C-propeptides of types V and XI procollagen chains to yield monomers that are incorporated into and control the diameters of collagen type I and II fibrils, respectively; processing of precursors for laminin 5 and collagen type VII, both of which are involved in securing epidermis to underlying dermis; and maturation of small leucine-rich proteoglycans. The BMP1/TLD-related metalloproteinases are also capable of activating the vertebrate transforming growth factor-beta (TGF-beta)-like "chalones" growth differentiation factor 8 (GDF8, also known as myostatin), and GDF11 (also known as BMP11), involved in negative feedback inhibition of muscle and neural tissue growth, respectively; by freeing them from noncovalent latent complexes with their cleaved prodomains. BMP1/TLD-like proteinases also liberate the vertebrate TGF

  17. IAEA/WHO TLD postal dose audit service and high precision measurements for radiotherapy level dosimetry

    International Nuclear Information System (INIS)

    Izewska, J.; Bera, P.; Vatnitsky, S.

    2002-01-01

    Since 1969 the International Atomic Energy Agency, together with the World Health Organization, has performed postal TLD audits to verify calibration of radiotherapy beams in developing countries. The TLD programme also monitors activities of Secondary Standard Dosimetry Laboratories (SSDLs). The programme has checked approximately 4000 clinical beams in over 1100 hospitals, and in many instances significant errors have been detected in the beam calibration. Subsequent follow-up actions help to resolve the discrepancies, thus preventing further mistreatment of patients. The audits for SSDLs check the implementation of the dosimetry protocol in order to assure proper dissemination of dosimetry standards to the end-users. The TLD audit results for SSDLs show good consistency in the basic dosimetry worldwide. New TLD procedures and equipment have recently been introduced by the IAEA that include a modified TLD calibration methodology and computerised tools for automation of dose calculation from TLD readings. (author)

  18. The characteristics of CaF2:Tm crystals (TLD-300) irradiated by electromagnetic radiation

    International Nuclear Information System (INIS)

    Ben-Shachar, B.; Yona, S.; Laichter, Y.; German, U.; Weiser, G.

    1985-09-01

    The main characteristics of the CaF 2 :Tm crystals (TLD-300), as a dosimeter, were measured: the glow curve, sensitivity, linearity, fading and energy dependence for photons, and compared to those of LiF (TLD-100) and CaF 2 :Dy (TLD-200). It was found that CaF 2 :Tm can be used for environmental dosimetry by reading the crystals after four days. (Author)

  19. Ten years experience with a large computerized TLD-personnel monitoring system

    International Nuclear Information System (INIS)

    Duftschmid, K.E.

    1986-01-01

    It is now ten years since our Institute for Radiation Protection has fully replaced its filmdosimetry service by a computerized automated TLD system. Presently more than 13000 radiation workers are monthly monitored by three automated TLD readers linked to the computer center. The paper describes system hardware and software and experience gained in long-term routine operation. In particular the introduction of the new ICRU quantities for personnel dosimetry in the existing TLD system is discussed. (Author)

  20. Study of a method based on TLD detectors for in-phantom dosimetry in BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Gambarini, G. [Dept. of Physics of the Univ., Via Celoria 16, 20133 Milan (Italy); INFN, Natl. Inst. of Nuclear Physics, Via Celoria 16, 20133 Milan (Italy); Klamert, V. [Dept. of Nuclear Eng. of Polytechnic, CESNEF, Via Ponzio 34/3, 20133 Milan (Italy); Agosteo, S. [INFN, Natl. Inst. of Nuclear Physics, Via Celoria 16, 20133 Milan (Italy); Dept. of Nuclear Eng. of Polytechnic, CESNEF, Via Ponzio 34/3, 20133 Milan (Italy); Birattari, C.; Gay, S. [Dept. of Physics of the Univ., Via Celoria 16, 20133 Milan (Italy); INFN, Natl. Inst. of Nuclear Physics, Via Celoria 16, 20133 Milan (Italy); Rosi, G. [FIS-ION, ENEA, Casaccia, Via Anguillarese 301, 00060 Santa Maria di Galeria, Rome (Italy); Scolari, L. [Dept. of Physics of the Univ., Via Celoria 16, 20133 Milan (Italy); INFN, Natl. Inst. of Nuclear Physics, Via Celoria 16, 20133 Milan (Italy)

    2004-07-01

    A method has been developed, based on thermoluminescent dosemeters (TLD), aimed at measuring the absorbed dose in tissue-equivalent phantoms exposed to thermal or epithermal neutrons, separating the contributions of various secondary radiation generated by neutrons. The proposed method takes advantage of the very low sensitivity of CaF{sub 2}:Tm (TLD-300) to low energy neutrons and to the different responses to thermal neutrons of LiF:Mg,Ti dosemeters with different {sup 6}Li percentage (TLD-100, TLD-700, TLD-600). The comparison of the results with those obtained by means of gel dosemeters and activation foils has confirmed the reliability of the method. The experimental modalities allowing reliable results have been studied. The glow curves of TLD-300 after gamma or neutron irradiation have been compared; moreover, both internal irradiation effect and energy dependence have been investigated. For TLD-600, TLD-100 and TLD-700, the suitable fluence limits have been determined in order to avoid radiation damage and loss of linearity. (authors)

  1. Dosimetric characteristics of a TLD dosemeter with extremities

    International Nuclear Information System (INIS)

    Molina P, D.; Diaz B, E.; Lien V, R.

    1999-01-01

    It was designed a TLD dosemeter for the monitoring of the extremities. This one consists in a metallic ring with a circular orifice where is arranged a T L detector of LiF: Mg,Ti (Model JR1152C) 5 x 5 x 0.8 mm 3 covered by a polyethylene fine layer. In this work were studied the dosimetric properties of the dosemeter for its application in the dosimetry of extremities for photonic radiation. the results obtained allow conclude that the designed dosemeter can be used for the extremities monitoring. (Author)

  2. Dosimetry Measurements around the Angiography Units Using Thermoluminescence Detectors (TLD)

    International Nuclear Information System (INIS)

    Salah El-den, T.; Shahein, A.Y.; Gomaa, M.A.

    2008-01-01

    The thermoluminescent dosimeters (TLDs) are widely used not only in the field of personnel monitoring (dosimetry) service for ionizing radiation to medical, and research communities, but also for measurements of X-rays emitted from different angiography's unit. Measurements ionizing radiation around the bed area during cardiac catheterization procedures using X-rays was measured. TLD Badges used to determine the annual effective doses, the safe distance for the staff to minimize radiation exposure and the effectiveness of shield and used leaded apron. The results indicated that annual effective dose for by angiography cardiac Catheterization room may exceed the limits

  3. NRC TLD Direct Radiation Monitoring Network. Progress report, January-June 1981

    International Nuclear Information System (INIS)

    1982-04-01

    This report provides the status and results of the NRC Thermoluminescent Dosimeter (TLD) Direct Radiation Monitoring Network. It presents the radiation levels measured in the vicinity of 55 NRC-licensed facility sites throughout the country for the first half of 1981. The program objectives, scope, and methodology are given. The TLD system, dosimeter location, data processing scheme, and quality assurance program are outlined

  4. A TLD dose algorithm using artificial neural networks

    International Nuclear Information System (INIS)

    Moscovitch, M.; Rotunda, J.E.; Tawil, R.A.; Rathbone, B.A.

    1995-01-01

    An artificial neural network was designed and used to develop a dose algorithm for a multi-element thermoluminescence dosimeter (TLD). The neural network architecture is based on the concept of functional links network (FLN). Neural network is an information processing method inspired by the biological nervous system. A dose algorithm based on neural networks is fundamentally different as compared to conventional algorithms, as it has the capability to learn from its own experience. The neural network algorithm is shown the expected dose values (output) associated with given responses of a multi-element dosimeter (input) many times. The algorithm, being trained that way, eventually is capable to produce its own unique solution to similar (but not exactly the same) dose calculation problems. For personal dosimetry, the output consists of the desired dose components: deep dose, shallow dose and eye dose. The input consists of the TL data obtained from the readout of a multi-element dosimeter. The neural network approach was applied to the Harshaw Type 8825 TLD, and was shown to significantly improve the performance of this dosimeter, well within the U.S. accreditation requirements for personnel dosimeters

  5. Environmental radiation monitoring of nuclear sites by thermoluminescent dosimeters (TLD)

    International Nuclear Information System (INIS)

    Duftschmid, K.E.; Strachotinsky, Ch.

    1978-04-01

    The measurement of environmental radiation doses around nuclear facilities requires the detection of few mrem/year. The properties of the automatic TLD-system Harshaw Mod. 2271 for such measurements have been evaluated under practical conditions and optimized techniques derived. The automatic TLD-system is based on LiF dosimeter cards with two crystals providing gamma and beta dose values. Limit of detection defined as three standard deviations of residuel dose is 1,2 mR. Automatic readout combined with electronic data evaluation are especially useful for large monitoring networks. Practical intercomparisons of this dosimeter with bulb-type CaF 2 detectors have been performed showing good agreement of both detector. Although bulb-dosimeters proved to be extremely sensitive with a limit of detection at 0,012 mR which makes them very suitable for very short exposure times, the automatic LiF system is superior in regards of man power requirement if monthly monitoring periods are sufficient. The system has been tested in practice during two international intercomparisons performed by the US Department of Energy - Health and Safety Laboratory New York and the Physikalisch Technische Bundesanstalt Braunschweig, Germany, showing excellent agreement. Furthermore a routine monitoring network consisting of 12 measurement positions around the Research Center Seibersdorf has been operated with this technique since more than two years. (author)

  6. Influences of scattering radiation in a TLD irradiation room, 2

    International Nuclear Information System (INIS)

    Suzuki, Osamu; Suwa, Shigeo

    1985-01-01

    The influence of scattering radiation (SR) on radiation dose rate (DR) in a TLD irradiation room was assessed. A single SD from a standard TLD apparatus, i.e., an acrylic or aluminum table, was examined. The maximum DR was attained at approximately 80 cm from the radiation source. Energy spectra of SR ranged up to the energy of direct radiation beam. Circular SD at one m from the radiation source, which contributed to DR to the direct radiation beam, was almost homogeneous. SD was large near the irradiation table, and the influence of SD on DR became smaller with SD being vertically farther from the apparatus. The influence of SD on RD to the direct radiation beam became less with an increase in gamma ray energy. At one m from the radiation source, 6 - 7 % of SD contributed to DR to the direct radiation beam for 0.662 MeV of gamma ray. This figure was one half of that with NaI (Tl) scintillation detector. (Namekawa, K.)

  7. Response of TLD-100"T"M microtubes to two RQR3 quality radiation beams

    International Nuclear Information System (INIS)

    Nunes, M.G.; Villani, D.; Almeida, S.B.; Vivolo, V.; Yoriyaz, H.; Louis, G.M.J.

    2016-01-01

    The present work compares the response of TLD-100"T"M microcubes to two RQR 3 diagnostic radiology reference quality radiation beams, defined by IEC-61267 norm, aiming to evaluate the detectability of TLD-100"T"M energy dependence reported in literature within the same reference quality radiation range. TLD-100"T"M microcubes reproducibility is assessed through the response of a second set of TLD-100"T"M microcubes, evaluated in a second thermoluminescence reader, to the RQR 3 diagnostic radiology reference quality radiation beam implemented at the Laboratorio de Calibracao de Instrumentos of IPEN, Sao Paulo, SP, Brazil. The dependence of TLD-100"T"M microcubes TL response was not detectable in these conditions and the reproducibility of the measurements is 90,2%. (author)

  8. Brazilian two-component TLD albedo neutron individual monitoring system

    Energy Technology Data Exchange (ETDEWEB)

    Martins, M.M., E-mail: marcelo@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD), Av. Salvador Allende, s/n, CEP: 22780-160, Rio de Janeiro, RJ (Brazil); Mauricio, C.L.P., E-mail: claudia@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD), Av. Salvador Allende, s/n, CEP: 22780-160, Rio de Janeiro, RJ (Brazil); Fonseca, E.S. da, E-mail: evaldo@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD), Av. Salvador Allende, s/n, CEP: 22780-160, Rio de Janeiro, RJ (Brazil); Silva, A.X. da, E-mail: ademir@con.ufrj.b [Coordenacao dos Programas de Pos-Graduacao em Engenharia, COPPE/PEN Caixa Postal 68509, CEP: 21941-972, Rio de Janeiro, RJ (Brazil)

    2010-12-15

    Since 1983, Instituto de Radioprotecao e Dosimetria, Brazil, uses a TLD one-component albedo neutron monitor, which has a single different calibration factor specifically for each installation type. In order to improve its energy response, a two-component albedo monitor was developed, which measure the thermal neutron component besides the albedo one. The two-component monitor has been calibrated in reference neutron fields: thermal, five accelerator-produced monoenergetic beams (70, 144, 565, 1200 and 5000 keV) and five radionuclide sources ({sup 252}Cf, {sup 252}Cf(D{sub 2}O), {sup 241}Am-Be, {sup 241}Am-B and {sup 238}Pu-Be) at several distances. Since January 2008, mainly Brazilian workers who handle neutron sources at different distances and moderation, such as in well logging and calibration facilities are using it routinely.

  9. Performance analysis of the TNO TLD individual monitoring service

    International Nuclear Information System (INIS)

    Dijk, J.W.E. van; Julius, H.W.

    1990-01-01

    The purpose of this study was to analyse the performance and to establish the lowest detectable occupational dose (LDOD) of the TNO TL dosemeter, in use for large scale routine individual monitoring since 1983. The TNO individual monitoring service uses three TLD reader systems and over 45000 TL dosemeters, designed to measure H s (0.07) and H p (10). Each reader system is normalised daily and each individual dosemeter is calibrated every ten readout cycles. The performance of the service is monitored by a double blind experimental set-up. A series of 10 routine dosemeters is issued every fortnight, mailed, exposed by staff not involved in the monitoring service, sent back and evaluated. The conclusion of this study is that the lowest detectable occupational dose is less than 0.04 mSv and that the integrated dose at the level of the annual dose limit is measured within 2%. (author)

  10. Analysis of uncertainties in the IAEA/WHO TLD postal dose audit system

    Energy Technology Data Exchange (ETDEWEB)

    Izewska, J. [Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Wagramer Strasse 5, Vienna (Austria)], E-mail: j.izewska@iaea.org; Hultqvist, M. [Department of Medical Radiation Physics, Karolinska Institute, Stockholm University, Stockholm (Sweden); Bera, P. [Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Wagramer Strasse 5, Vienna (Austria)

    2008-02-15

    The International Atomic Energy Agency (IAEA) and the World Health Organisation (WHO) operate the IAEA/WHO TLD postal dose audit programme. Thermoluminescence dosimeters (TLDs) are used as transfer devices in this programme. In the present work the uncertainties in the dose determination from TLD measurements have been evaluated. The analysis of uncertainties comprises uncertainties in the calibration coefficient of the TLD system and uncertainties in factors correcting for dose response non-linearity, fading of TL signal, energy response and influence of TLD holder. The individual uncertainties have been combined to estimate the total uncertainty in the dose evaluated from TLD measurements. The combined relative standard uncertainty in the dose determined from TLD measurements has been estimated to be 1.2% for irradiations with Co-60 {gamma}-rays and 1.6% for irradiations with high-energy X-rays. Results from irradiations by the Bureau international des poids et mesures (BIPM), Primary Standard Dosimetry Laboratories (PSDLs) and Secondary Standards Dosimetry Laboratories (SSDLs) compare favourably with the estimated uncertainties, whereas TLD results of radiotherapy centres show higher standard deviations than those derived theoretically.

  11. Traceability of a panoramic gamma irradiator using different TLD systems as transfer instruments

    International Nuclear Information System (INIS)

    Romero, A.M.; Saez, J.C.

    1994-01-01

    This work shows the calibration in terms of the new operational radiological quantities Hp(10) and H*(10) for different TLD systems (Harshaw TLD-100 and Panasonic UD-802) used in personal and environmental monitoring. The irradiations were performed in the Spanish Reference Laboratory in radiation protection levels, managed by the CIEMAT Metrology of ionizing radiations Unit. With these data, different calibrations of a panoramic gamma irradiator in terms of the radiological quantity for unit of time were established, providing the traceability of the irradiator to the Reference Laboratory using the corresponding TLD systems as transfer instruments. (Author) 9 refs

  12. Traceability of a panoramic gamma irradiator using different TLD systems as transfer Instruments

    International Nuclear Information System (INIS)

    Romero, A. M.; Saez, J. C

    1994-01-01

    This work shows the calibration in terms of the new operational radiological quantities Hp (10) and H(10) for different TLD systems (Harshaw TLD-100 and Panasonic UD-002) used in personal and environmental monitoring. The irradiations were performed in the Spanish Reference Laboratory in radiation protection levels, managed by the CIEMAT Metrology of ionizing radiations Unit. With those data, different calibrations of a panoramic gamma irradiator in terms of the radiological quantity for unit of time were established, providing the traceability of the irradiator to the Reference Laboratory using the corresponding TLD systems as transfer instruments. (Author) 9 refs

  13. Experimental determination of the photon-energy dependent dose-to-water response of TLD600 and TLD700 (LiF:Mg,Ti) thermoluminescence detectors

    Energy Technology Data Exchange (ETDEWEB)

    Schwahofer, Andrea [Vivantes Clinic Neukoelln, Berlin (Germany). Dept. of Radiation Therapy; German Cancer Research Center, Heidelberg (Germany). Medical Physics in Radiation Therapy; Feist, Harald [Munich Univ. (Germany). Dept. of Radiation Therapy; Georg, Holger [PTW Freiburg (Germany). Calibration Lab.; Haering, Peter; Schlegel, Wolfgang [German Cancer Research Center, Heidelberg (Germany). Medical Physics in Radiation Therapy

    2017-05-01

    The aim of this study has been the experimental determination of the energy dependent dose-to-water response of TLD600 and TLD700 thermoluminescent detectors (Harshaw) in X-ray beams with mean photon energies from about 20 to 200 keV in comparison with {sup 60}Co gamma rays and 6 MV X-rays. Experiments were carried out in collaboration with the German secondary standard laboratory PTW Freiburg. The energy dependent relative responses of TLD600 and TLD700 thermoluminescence detectors were determined at radiation qualities between 30 kV{sub p} and 280 kV{sub p}. The overall uncertainty of the measured values was characterized by standard deviations varying from 1.2 to 3%. The present results agree with previous studies on the energy dependent dose-to-water response of TLD100. As an application example, the results were used to measure doses associated with X-ray imaging in image-guided radiotherapy.

  14. Vivo dosimetry using TLD detectors in prostate seed implants of I-125: preliminary results

    International Nuclear Information System (INIS)

    Sanchez-Reyes, A.; Pedro, A.; Bassas, P.; Duch, M. A.; Cros, M.; Mane, S.

    2011-01-01

    We present preliminary results of a new in vivo dosimetry technique that could allow to know immediately after implantation of the prostate if the dose distribution determined by the scheduler is similar to the actual dose measured with TLD detectors.

  15. NRC [Nuclear Regulatory Commission] TLD [thermoluminescent dosimeter] direct radiation monitoring network

    International Nuclear Information System (INIS)

    Struckmeyer, R.; McNamara, N.

    1989-09-01

    This report provides the status and results of the NRC Thermoluminescent Dosimeter (TLD) Direct Radiation Monitoring Network. It presents the radiation levels measured in the vicinity of NRC licensed facility sites throughout the country for the second quarter of 1989

  16. NRC TLD [thermoluminescent dosimeter] Direct Radiation Monitoring Network: Progress report, January-March 1988

    International Nuclear Information System (INIS)

    Struckmeyer, R.; McNamara, N.

    1988-06-01

    This report provides the status and results of the NRC Thermoluminescent Dosimeter (TLD) Direct Radiation Monitoring Network. It presents the radiation levels measured in the vicinity of NRC licensed facility sites throughout the country for the first quarter of 1988

  17. Dosimetric properties of the 'Pille' portable, wide dose range TLD reader

    International Nuclear Information System (INIS)

    Szabo, P.P.; Feher, I.; Deme, S.; Szabo, B.; Vagvoelgyi, J.

    1986-01-01

    The dosimetric properties of a portable TLD reader are described. The TLD system named 'Pille' or 'moth' consists of a lightweight battery-operated portable TLD reader and its CaSO 4 :Dy bulb dosemeters. The reproducibility of the TLD system at constant temperature was found to be better than + -2%, and the mean time between failures exceeded 5 years. The dose range of the system is wide, covering more than 6 orders of magnitude, from 5 μGy to 10 Gy. The energy dependence of the CaSO 4 :Dy bulb dosemeters is less than + - 20% above 100 keV in the energy compensation capsules. Without additional annealing, the bulb dosemeters can be re-used at least 100 times, which is an important aspect during in situ measurements. (author)

  18. NRC TLD direct radiation monitoring network: Progress report, April--June 1988

    International Nuclear Information System (INIS)

    Struckmeyer, R.; McNamara, N.

    1988-09-01

    This report provides the status and results of the NRC Thermoluminescent Dosimeter (TLD) Direct Radiation Monitoring Network. It presents the radiation levels measured in the vicinity of NRC licensed facility sites throughout the country for the second quarter of 1988

  19. Methods on TLD management be applicable in nuclear power plantsunder the multi-reactor operational mode

    International Nuclear Information System (INIS)

    Luo Huiyong; Wen Qinghua; Li Ruirong; Yu Enjian

    2006-01-01

    This paper discusses the methods on management of TLD dosimeters adopted in DNMC and other NPPs, analyzes and evaluates their both defects and advantages. Facing the coming of the multi-reactor operational mode applied in NPPs, a new method intelligent management mode is put forward, this optimized method not only assures the accuracy of TLD's measurement but also reduces the cost of production and improves the efficiency of management greatly. (authors)

  20. TLD system for the monitoring of the environmental radioactivity

    International Nuclear Information System (INIS)

    Stochioiu, Ana; Sahagia, Maria; Tudor, Ion

    2008-01-01

    The paper presents a high sensitivity TLD system, designed for the survey of the environmental radioactivity. It is based on the use of TL detectors type LiF:Mg, Cu, P, commercially known as GR-200A. The dosimeter designed in our Institute, contains 3 detectors, and the measurement value is calculated as the arithmetic mean. A very sensitive, TL Reader, READER ANALYSER RA'94 was chosen and an optimal thermal cycle was designed, such as to enhance the measurement performances. For each placement, a set of 3 dosemeters is used, and survey intervals from 1 to 100 days, depending on the radioactivity level and reporting requirements, are selected. The technical characteristics of the system were determined by exposing the dosimeters in reference X and gamma radiation fields, such as required by the IEC standard 61066:iun.2006 'Thermoluminescence dosimetry systems for personal and environmental monitoring'. The main technical parameters are of highest quality and recommend it for use in the survey of the environmental radioactivity, at the level of ambient dose equivalent rate, due to normal natural radioactivity, in open areas. The paper describes the method of characterisation and measurement results, as well as their relevance. (author)

  1. The application of artificial neural networks to TLD dose algorithm

    International Nuclear Information System (INIS)

    Moscovitch, M.

    1997-01-01

    We review the application of feed forward neural networks to multi element thermoluminescence dosimetry (TLD) dose algorithm development. A Neural Network is an information processing method inspired by the biological nervous system. A dose algorithm based on a neural network is a fundamentally different approach from conventional algorithms, as it has the capability to learn from its own experience. The neural network algorithm is shown the expected dose values (output) associated with a given response of a multi-element dosimeter (input) many times.The algorithm, being trained that way, eventually is able to produce its own unique solution to similar (but not exactly the same) dose calculation problems. For personnel dosimetry, the output consists of the desired dose components: deep dose, shallow dose, and eye dose. The input consists of the TL data obtained from the readout of a multi-element dosimeter. For this application, a neural network architecture was developed based on the concept of functional links network (FLN). The FLN concept allowed an increase in the dimensionality of the input space and construction of a neural network without any hidden layers. This simplifies the problem and results in a relatively simple and reliable dose calculation algorithm. Overall, the neural network dose algorithm approach has been shown to significantly improve the precision and accuracy of dose calculations. (authors)

  2. TLD DRD dose discrepancy: role of beta radiation fields

    International Nuclear Information System (INIS)

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

    2014-01-01

    Ionization chamber based direct reading/pocket dosimeters (DRDs), are used along with the legal dosimeters (thermoluminescent dosimeters-TLDs) for day to day monitoring and control of radiation doses received by radiation workers. The DRDs are routinely used along with the passive dosimeters (TLDs) in nuclear industry at different radiation installations where radiation levels could vary significantly and the possibility of receiving doses beyond investigation levels by radiation workers is not ruled out. Recently, recommendations for dealing with discrepancies between personal dosimeter systems used in parallel were issued by ISO. The present study was performed to measure the response of ionization chamber based pocket dosimeters to various beta sources having energy (E max ) ranging from 0.224 MeV-3.54 MeV. It is expected that the above study will be useful in resolving the disparity between TLD and DRD doses at those radiation installations where radiation workers are likely to be exposed simultaneously from photons and beta particles

  3. Dose measurements in space by the Hungarian Pille TLD system

    International Nuclear Information System (INIS)

    Apathy, I.; Deme, S.; Feher, I.; Akatov, Y.A.; Reitz, G.; Arkhanguelski, V.V.

    2002-01-01

    Exposure of crew, equipment, and experiments to the ambient space radiation environment in low Earth orbit poses one of the most significant problems to long-term space habitation. Accurate dose measurement has become increasingly important during the assembly (extravehicular activity (EVA)) and operation of space stations such as on Space Station Mir. Passive integrating detector systems such as thermoluminescent dosemeters (TLDs) are commonly used for dosimetry mapping and personal dosimetry on space vehicles. The well-known advantages of passive detector systems are their independence of power supply, small dimensions, high sensitivity, good stability, wide measuring range, resistance to environmental effects, and relatively low cost. Nevertheless, they have the general disadvantage that for evaluation purposes they need a laboratory or large--in mass and power consumption--terrestrial equipment, and consequently they cannot provide time-resolved dose data during long-term space flights. KFKI Atomic Energy Research Institute (KFKI AEKI) has developed and manufactured a series of thermoluminescent dosemeter systems for measuring cosmic radiation doses in the 10 μGy to 10 Gy range, consisting of a set of bulb dosemeters and a compact, self-contained, TLD reader suitable for on-board evaluation of the dosemeters. By means of such a system, highly accurate measurements were carried out on board the Salyut-6, -7 and Mir Space Stations as well as on the Space Shuttle. A detailed description of the system is given and the comprehensive results of these measurements are summarised

  4. Use of MCNP to compare the response of dose deposited in the TLD 100, TLD 600 and TLD 700 in radiation fields due to {sup 60}Co and {sup 241}AmBe source; Uso do MCNP para comparacao das respostas de dose depositada nos TLD 100, TLD 600 e TLD 700 em campos de irradiacao devido a fontes de {sup 60}Co e {sup 241}AmBe

    Energy Technology Data Exchange (ETDEWEB)

    Cavalieri, Tassio A.; Castro, Vinicius A.; Siqueira, Paulo T.D., E-mail: tassio.cavalieri@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2012-08-15

    The successes of Boron Neutron Capture Therapy (BNCT) depend on the ability to deliver an adequate irradiation field to the target cells. Neutron beams used in BNCT are mostly driven from reactors and therefore, not only have a neutron energy range which far exceeds the thermal region but also do have a great gamma component. Beam characterization and dosimetry are consequently one of the essential procedures to be overcome to properly apply this technique. One of the methods currently used in mixed field (field containing both neutron and gamma) characterization, lies on the use of a pair of detectors with distinct responses to each beam component. But this technique needs to be better understood of how each thermoluminescent dosimeter (TLD) behaves in a mixed field or in a pure field. This work presents the results of a set of simulations performed in order to analyze the response of three ordinary types of TLDs - TLD 100, TLD 600 and TLD 700 - submitted to different irradiation fields from a Cobalt source and an Americium-Beryllium source inside a paraffin disk. And is also a possible method for performing the selection and calibration of theses TLDs. (author)

  5. Assessment of dose using TLD during activity handling at RPhL, BRIT

    International Nuclear Information System (INIS)

    Choughule, Nitin V.; Bairwa, S.M.; Murali, S.; Rakesh, R.B.; Madhumita, B.; Adtani, M.M.; Mehra, Kiran; Padmanabhan, D.; Borkute, S.D.; Pal, N.; Sachdev, S.S.

    2012-01-01

    Radiopharmaceutical Lab (RPhL), BRIT undertakes production, supply of radiopharmaceuticals. At RPhL short lived isotopes 131 I, 99 Mo, 99m Tc, 125 I, 153 Sm, 32 P and 51 Cr, are handled with total activity handled per week ranging from MBq to TBq (mCiCi). Radiological survey provides idea on radiation level helps to ensure safe working condition. In order to improve the working condition and to estimate the integrated dose over a period of week with uniform pattern of activity handling in the period, a study was carried out using TLD badges. Specifically prepared TLD badges containing CaSO 4 :Dy phosphor were placed at various locations at RPhL It is used for personnel monitoring. One set of TLD was exposed for a week long period while the other set was exposed only during activity handling, kept in the lead pot during the rest of the period. Dose measured by TLDs were compared with the dose estimated using the survey data for the respective locations as well as with the dose estimated using the activity handled by taking into account the time, distance and shielding. The maximum radiation level recorded during lab survey was used to estimate the TLD exposure during the period. It was observed that results on TLD dose measurement and estimated doses using survey results were of same order. The cumulative TLD dose recorded for week duration (168 h) was significantly higher than doses recorded by exposed TLD only during activity handling (8 h). It was expected that the TLD dose would not be more than dose estimated using radiation survey data, while in 3 among 8 experimental TLDs, the dose was ∼ 25% higher. This could be due to the movement of active material or open handling of activity do not get reflected during normal radiation survey and contribution from background radiation at the lab where those TLDs were placed. The individual dose of all the personnel working in different labs were well within the relevant dose limits indicating the safe working condition

  6. Hand book on the use of TLD badge based on CaSO4:Dy teflon TLD discs for individual monitoring

    International Nuclear Information System (INIS)

    Pradhan, A.S.; Adtani, M.M.; Varadharajan, G.; Bakshi, A.K.; Srivastava, Kshama; Bihari, R.R.

    2002-10-01

    Individual monitoring is one of the most important aspects of a radiation protection programme. In India, an official and centralized personnel monitoring service to radiation workers started in 1952. With the indigenous development of a TLD badge system in 1975 at Bhabha Atomic Research Centre, decentralization of monitoring service was initiated. At present, about 40,000 radiation workers are monitored using this system through twelve TLD units located in different parts of the country, including a private accredited laboratory. Regulatory and other inspecting bodies have often asked outstation TLD units to produce a duly approved document on the procedures being practiced for the assessment of personal doses. A need for such a document has also been felt to ensure the uniformity in processing of dosemeters, recording and reporting of doses by different TLD units and to provide guidelines regarding the infrastructure requirement. This document in the form of a handbook has been prepared to cater to the above needs. The handbook is expected to provide necessary guidelines not only to the newcomers/ forthcoming units and the existing laboratories but also to help the regulators, inspectors and assessors. (author)

  7. SU-E-I-09: Application of LiF:Mg,Cu (TLD-100H) Dosimeters for in Diagnostic Radiology

    International Nuclear Information System (INIS)

    Sina, S; Zeinali, B; Karimipourfard, M; Lotfalizadeh, F; Sadeghi, M; Faghihi, R

    2014-01-01

    Purpose: Accurate dosimetery is very essential in diagnostic radiology. The goal of this study is to verify the application of LiF:Mg,Cu,P (TLD100H) in obtaining the Entrance skin dose (ESD) of patients undergoing diagnostic radiology. The results of dosimetry performed by TLD-100H, were compared with those obtained by TLD100, which is a common dosimeter in diagnostic radiology. Methods: In this study the ESD values were measured using two types of Thermoluminescence dosimeters (TLD-100, and TLD-100H) for 16 patients undergoing diagnostic radiology (lumbar spine imaging). The ESD values were also obtained by putting the two types of TLDs at the surface of Rando phantom for different imaging techniques and different views (AP, and lateral). The TLD chips were annealed with a standard procedure, and the ECC values for each TLD was obtained by exposing the chips to equal amount of radiation. Each time three TLD chips were covered by thin dark plastic covers, and were put at the surface of the phantom or the patient. The average reading of the three chips was used for obtaining the dose. Results: The results show a close agreement between the dose measuered by the two dosimeters.According to the results of this study, the TLD-100H dosimeters have higher sensitivities (i.e.signal(nc)/dose) than TLD-100.The ESD values varied between 2.71 mGy and 26.29 mGy with the average of 11.89 mGy for TLD-100, and between 2.55 mGy and 27.41 mGy with the average of 12.32 mGy for measurements. Conclusion: The TLD-100H dosimeters are suggested as effective dosimeters for dosimetry in low dose fields because of their higher sensitivities

  8. SU-E-I-09: Application of LiF:Mg,Cu (TLD-100H) Dosimeters for in Diagnostic Radiology

    Energy Technology Data Exchange (ETDEWEB)

    Sina, S [Radiation Research Center, Shiraz University, Shiraz (Iran, Islamic Republic of); Zeinali, B; Karimipourfard, M; Lotfalizadeh, F; Sadeghi, M [Nuclear Engineering Department, Shiraz University, Shiraz (Iran, Islamic Republic of); Faghihi, R [Radiation Research Center, Shiraz University, Shiraz (Iran, Islamic Republic of); Nuclear Engineering Department, Shiraz University, Shiraz (Iran, Islamic Republic of)

    2014-06-01

    Purpose: Accurate dosimetery is very essential in diagnostic radiology. The goal of this study is to verify the application of LiF:Mg,Cu,P (TLD100H) in obtaining the Entrance skin dose (ESD) of patients undergoing diagnostic radiology. The results of dosimetry performed by TLD-100H, were compared with those obtained by TLD100, which is a common dosimeter in diagnostic radiology. Methods: In this study the ESD values were measured using two types of Thermoluminescence dosimeters (TLD-100, and TLD-100H) for 16 patients undergoing diagnostic radiology (lumbar spine imaging). The ESD values were also obtained by putting the two types of TLDs at the surface of Rando phantom for different imaging techniques and different views (AP, and lateral). The TLD chips were annealed with a standard procedure, and the ECC values for each TLD was obtained by exposing the chips to equal amount of radiation. Each time three TLD chips were covered by thin dark plastic covers, and were put at the surface of the phantom or the patient. The average reading of the three chips was used for obtaining the dose. Results: The results show a close agreement between the dose measuered by the two dosimeters.According to the results of this study, the TLD-100H dosimeters have higher sensitivities (i.e.signal(nc)/dose) than TLD-100.The ESD values varied between 2.71 mGy and 26.29 mGy with the average of 11.89 mGy for TLD-100, and between 2.55 mGy and 27.41 mGy with the average of 12.32 mGy for measurements. Conclusion: The TLD-100H dosimeters are suggested as effective dosimeters for dosimetry in low dose fields because of their higher sensitivities.

  9. Deviations outside the acceptance limits in the IAEA/WHO TLD audits for radiotherapy hospitals

    International Nuclear Information System (INIS)

    Vatnitsky, S.; Izewska, J.

    2002-01-01

    The main purpose of the IAEA/WHO TLD postal dose audit programme for dosimetry in radiotherapy is to provide an independent verification of the dose delivered by treatment machines in radiotherapy hospitals. The results of the TLD audit are considered acceptable if the relative deviation between the participant's stated dose and the TLD determined dose is within ±5%. The goal of this note is to draw the attention of participants of the TLD programme to some of the common reasons for deviations outside the acceptance limits. Armed with this knowledge, other participants may avoid similar problems in the future. The analysis of deviations presented here is based on the results of TLD audits of the calibration of approximately 1000 Co-60 beams and 600 high-energy X-ray beams performed in the period 1996-2001. A total of 259 deviations outside the ±5% limits have been detected, including 204 deviations for Co-60 beams (20% of all Co-60 beams checked) and 55 for high-energy X-ray beams (10% of all X-ray beams checked). It is worth mentioning that the percentage of large deviations (beyond 10%) is also higher for Co-60 beams than for high-energy X-ray beams. Some problems may be caused by obsolete dosimetry equipment or poor treatment machine conditions. Other problems may be due to insufficient training of staff working in radiotherapy. The clinical relevance of severe TLD deviations detected in the audit programme was confirmed in many cases, but, fortunately, not all-poor dosimetric results reflect deficiencies in the calibration of clinical beams or machine faults. Sometime it happens, that the TLDs are irradiated with an incorrect dose due to misunderstanding of the instructions on how to perform the TLD irradiation. Such dosimetry errors would have no direct impact on actual dose delivered to a patient

  10. Evaluation of TLD dose response compared to MCNP-5 simulation of diagnostic X ray equipment - radiation diagnostic image

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez G, R.; Cavalieri, T. A.; De Paiva, F.; Dalledone S, P. de T.; Yoriyaz, H. [Instituto de Pesquisas Energeticas e Nucleares, Centro de Engenharia Nuclear / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil); Rodrigues F, M. A. [Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, Departamento de Dermatologia e Radioterapia, Av. Prof. Montenegro s/n, Rubiao Junior, 18601-970 Botucatu (Brazil); Vivolo, V., E-mail: chancez@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares, Gerencia de Metrologia das Radiacoes / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil)

    2014-08-15

    The thermo luminescent dosimeter (TLD) is used as a radiation dosimeter and can be used as environmental and staff personnel monitoring. The TLD measures ionizing radiation exposure by a process in which the amount of radiation collected by the dosimeter is converted in visible light when the crystal is heated. The amount of emitted light is proportional to the radiation exposure, and then the response of the TLD must be the related to the real dose. In this work it was used twenty four TLD 700 in order to obtain eight values of doses from a diagnostic X-ray equipment. The TLD-700 is a LiF TLD enriched with {sup 7}Li isotope. One way to compare and study the response of TLD is by Monte Carlo method, which has been used as a computational tool to solve problems stochastically. This method can be applied to any geometry, even those where the boundary conditions are unknown, making the method particularly useful to solve problems a priori. In this work it was modeled the X-ray tube exactly as the one used to irradiate the TLD, after the simulation and the TLD irradiation the results of dose value from both were compared. (Author)

  11. Evaluation of TLD dose response compared to MCNP-5 simulation of diagnostic X ray equipment - radiation diagnostic image

    International Nuclear Information System (INIS)

    Sanchez G, R.; Cavalieri, T. A.; De Paiva, F.; Dalledone S, P. de T.; Yoriyaz, H.; Rodrigues F, M. A.; Vivolo, V.

    2014-08-01

    The thermo luminescent dosimeter (TLD) is used as a radiation dosimeter and can be used as environmental and staff personnel monitoring. The TLD measures ionizing radiation exposure by a process in which the amount of radiation collected by the dosimeter is converted in visible light when the crystal is heated. The amount of emitted light is proportional to the radiation exposure, and then the response of the TLD must be the related to the real dose. In this work it was used twenty four TLD 700 in order to obtain eight values of doses from a diagnostic X-ray equipment. The TLD-700 is a LiF TLD enriched with 7 Li isotope. One way to compare and study the response of TLD is by Monte Carlo method, which has been used as a computational tool to solve problems stochastically. This method can be applied to any geometry, even those where the boundary conditions are unknown, making the method particularly useful to solve problems a priori. In this work it was modeled the X-ray tube exactly as the one used to irradiate the TLD, after the simulation and the TLD irradiation the results of dose value from both were compared. (Author)

  12. TLD Intercomparison in accelerators for radiotherapy in three Latin american countries; Intercomparacion TLD en aceleradores para radioterapia en tres paises latinoamericanos

    Energy Technology Data Exchange (ETDEWEB)

    Gaona, E.; Azorin N, J.; Perez, M.A.; Picon, C.; Castellanos, E.; Plazas, M.C.; Murcia, G.; Archundia, L. [Depto. El Hombre y su Ambiente. Universidad Autonoma Metropolitana, Calz. Del Hueso 1100, 04960 Mexico D.F. (Mexico)

    1998-12-31

    In Radiotherapy one of the objectives is to establish and to give follow up to quality assurance programs which make sure that the doses administered to the patients with cancer are a high probability of a success in external radiation. Likewise, one of the present preoccupations of the United Nations Agencies as well as the International Atomic Energy Agency and the Pan-American Health Organization is the optimal employment of the radiations in the treatment of cancer patients since the administered dose in Radiotherapy suffers considerable variations by the lack of quality assurance programs. The use of Electron linear accelerators requires a program of quality assurance that includes expert personnel, equipment and adequate facilities. The more used methodology for the dosimetry calibration and characterization of X-ray beams and high energy electrons for radiotherapy use is using a ionization chamber dosemeter calibrated in a regional secondary standardization laboratory. However, to establish and give follow up to the quality assurance programs it is necessary the dosimetric intercomparison through TLD. In this study it was designed plastic phantoms with TLD crystals and it was made its characterization to realize an absorbed dose analysis in the crystals exposed at X-ray beams 6 MV and high energy electrons 10 and 12 MeV to standardize the dosimetric procedures and proceeding to realize an International Pilot intercomparison of absorbed doses in TLD crystals in three Latin American countries: Mexico, Peru and Colombia with the participation of accelerators of five different institutions. The found results show that the majority of the measured doses with TLD in the different accelerators were in the 0.95-1.05 range though it had two cases outside of this range. The use of the phantoms with TLD crystals shows that they are of excellent aid to make analysis of the doses administered to the patients and an intercomparison of results to standardize procedures at

  13. A method to minimise the fading effects of LiF:Mg,Ti (TLD-600 and TLD-700) using a pre-heat technique.

    Science.gov (United States)

    Lee, YoungJu; Won, Yuho; Kang, Kidoo

    2015-04-01

    Passive integrating dosemeters [thermoluminescent dosimeter (TLD) and optically stimulated luminescence (OSL)] are the only legally permitted individual dosemeters for occupational external radiation exposure monitoring in Korea. Also its maximum issuing cycle does not exceed 3 months, and the Korean regulations require personal dosemeters for official assessment of external radiation exposure to be issued by an approved or rather an accredited dosimetry service according to ISO/IEC 17025. KHNP (Korea Hydro & Nuclear Power, LTD), a unique operating company of nuclear power plants (NPPs) in Korea, currently has a plan to extend a TLD issuing cycle from 1 to 3 months under the authors' fading error criteria, ±10%. The authors have performed a feasibility study that minimises post-irradiation fading effects within their maximum reading cycle employing pre-heating technique. They repeatedly performed irradiation/reading a bare TLD chip to determine optimum pre-heating conditions by analysing each glow curve. The optimum reading conditions within the maximum reading cycle of 3 months were decided: a pre-heating temperature of 165°C, a pre-heating time of 9 s, a heating rate of 25°C s(-1), a reading temperature of 300°C and an acquisition time of 10 s. The fading result of TLD-600 and TLD-700 carried by newly developed time temperature profile (TTP) showed a much smaller fading effect than that of current TTP. The result showed that the fading error due to a developed TTP resulted in a ∼5% signal loss, whereas a current TTP caused a ∼15% loss. The authors also carried out a legal performance test on newly developed TTP to confirm its possibility as an official dosemeter. The legal performance tests that applied the developed TTP satisfied the criteria for all the test categories. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. IAEA/ WHO TLD postal dose intercomparison results in Bangladesh

    International Nuclear Information System (INIS)

    Mollah, A.S.; Bhuiyan, N.U.; Rahman, S.

    2001-01-01

    Full text: For the accurate delivery of prescribed dose to the patients, high precision and accuracy in radiation dosimetry is required. The hospital/medical physicist is responsible for the accurate delivery of whole planned radiation doses to the patients prescribed by the radio therapist. The proper delivery of radiation doses depends upon the accurate output measurements of doses from the therapy machines. In Bangladesh, only six 60 Co units and five deep therapy machines are in use. Some more are expected to be installed soon. Still in 2001, none of the Government radiotherapy centers in Bangladesh was properly equipped with medical physicists as well as radiotherapy dosimetry equipment. Bangladesh Atomic Energy Commission (BAEC) is responsible for radiation safety in Bangladesh and BAEC has assigned Secondary Standard Dosimetry Laboratory (SSDL) of Bangladesh for providing dosimetry calibration to all radiotherapy centers in Bangladesh. The output measurements of therapy machines are performed once in a year by SSDL and the results are compared by participating in the annual TLD postal dose intercomparison program organized by IAEA/WHO SSDL Network. The absorbed dose to water is determined using IAEA dosimetry protocol (TRS 277 and 381) and water phantom of size 30 x 30 x 30 cm 3 , The measurements of SSDL are traceable to NPL of UK. The accuracy achieved in SSDL, Bangladesh has been found better than ± 3.5%, which is within the prescribed limit of dosimetry standard of IAEA. The methodology of output dose measurements in different radiotherapy centers in Bangladesh is described along with the IAEA/WHO intercomparison results

  15. Performance test of a portable TLD system for accidental doses

    International Nuclear Information System (INIS)

    Mihelic, M.; Stuhec, M.; Mitic, D.; Vekic, B.; Miljanic, S.; Ban, R.

    2005-01-01

    Full text: A portable TLD measuring system was constructed at the J. Stefan Institute many years ago, motivated by the thread of a catastrophic nuclear event. It was designed for fast measurements in accidental dosimetry mainly for military and civil protection use. The system consists of a robust portable measuring unit built for measurements in field conditions, sized about 40 cm in diameter and weighting 5 kg. Dosimeters are based on CaF 2 :Mn ceramic tablets closed in water resistant plastic housings. In original design producer assured measuring range from cGy to kGy. Specially designed energy compensating filters are used to satisfy requirements for energy response from 0,1 to 3 MeV. Stability of readings is maintained with the temperature stabilized light source. Measuring time for manually driven heating-reading cycle of one dosimeter is about 30 sec. Many systems of the type with sets of dosimeters were stored unused for some years in depositories of different institutions. Modernization of equipment in last years raised questions of applicability of such measurement systems for contemporary needs. The system was thus tested in a secondary standards dosimetry laboratory for compliance with up to date requirements for accidental individual monitoring. Dosimeter characteristics as repeatability, linearity and directional response were of particular interest. As a result of the tests, technical improvements are suggested to extent systems measuring capabilities in order to meet new standards. Possibilities of its use in different fields of dosimetry are discussed, where quick in field measurements of high doses is required as for example in medicine or in civil protection motivated by the new threads of terrorist attacks. (author)

  16. The study of new calibration features in the Harshaw TLD system

    International Nuclear Information System (INIS)

    Luo, L. Z.

    2007-01-01

    The Harshaw TLD system has three key calibration procedures: the Reader, the Dosemeter and the Algorithm. These functions must be properly calibrated for the system to achieve the optimum results. For the conventional reader and dosemeter calibration, Harshaw TLD recommends a pre-fade and a post-fade of 24-48 h when calibrating the system for LiF:Mg,Ti type dosemeter. It is also recommended that keeping the fade time consistent is important to maintain the quality of the system performance. In recent years, new calibration features have been introduced into the Harshaw TLD models 6600 and 8800 operating systems. These new features are Auto Calibration, Auto QC and Auto Blank, and they give the user the ability to set up the clear-expose-read process to be performed automatically in a sequence for each dosemeter. This saves processing time and keeps the fade time the same. However, since the fade time is near zero, will it affect the TLD system calibration factors? What should the user expect? This paper presents a study of the effect of Auto Calibration/Auto QC to the TLD operation. (authors)

  17. Improvement of Accuracy in Environmental Dosimetry by TLD Cards Using Three-dimensional Calibration Method

    Directory of Open Access Journals (Sweden)

    HosseiniAliabadi S. J.

    2015-06-01

    Full Text Available Background: The angular dependency of response for TLD cards may cause deviation from its true value on the results of environmental dosimetry, since TLDs may be exposed to radiation at different angles of incidence from the surrounding area. Objective: A 3D setting of TLD cards has been calibrated isotropically in a standard radiation field to evaluate the improvement of the accuracy of measurement for environmental dosimetry. Method: Three personal TLD cards were rectangularly placed in a cylindrical holder, and calibrated using 1D and 3D calibration methods. Then, the dosimeter has been used simultaneously with a reference instrument in a real radiation field measuring the accumulated dose within a time interval. Result: The results show that the accuracy of measurement has been improved by 6.5% using 3D calibration factor in comparison with that of normal 1D calibration method. Conclusion: This system can be utilized in large scale environmental monitoring with a higher accuracy

  18. Investigation of LiF, Mg and Ti (TLD-100 Reproducibility

    Directory of Open Access Journals (Sweden)

    Sadeghi M.

    2015-12-01

    Full Text Available LiF, Mg and Ti cubical TLD chips (known as TLD-100 are widely used for dosimetry purposes. The repeatability of TL dosimetry is investigated by exposing them to doses of (81, 162 and 40.5 mGy with 662keV photons of Cs-137. A group of 40 cubical TLD chips was randomly selected from a batch and the values of Element Correction Coefficient (ECC were obtained 4 times by irradiating them to doses of 81 mGy (two times, 162mGy and 40.5mGy. Results of this study indicate that the average reproducibility of ECC calculation for 40 TLDs is 1.5%, while these values for all chips do not exceed 5%.

  19. Investigation of LiF, Mg and Ti (TLD-100) Reproducibility.

    Science.gov (United States)

    Sadeghi, M; Sina, S; Faghihi, R

    2015-12-01

    LiF, Mg and Ti cubical TLD chips (known as TLD-100) are widely used for dosimetry purposes. The repeatability of TL dosimetry is investigated by exposing them to doses of (81, 162 and 40.5 mGy) with 662keV photons of Cs-137. A group of 40 cubical TLD chips was randomly selected from a batch and the values of Element Correction Coefficient (ECC) were obtained 4 times by irradiating them to doses of 81 mGy (two times), 162mGy and 40.5mGy. Results of this study indicate that the average reproducibility of ECC calculation for 40 TLDs is 1.5%, while these values for all chips do not exceed 5%.

  20. Optimization of the temperature profiles due to a nitrogen jet impinging on a TLD detector

    International Nuclear Information System (INIS)

    Cohen, I.; Bar-Kohany, T.; German, U.; Ziskind, G.

    2014-01-01

    A study was conducted to simulate the temperature profiles during readout in a typical, commercial thermo-luminescence dosimeter (TLD) chip and to optimize the readout conditions. The study makes use of a previously developed numerical model which calculates the crystal's temperature profile evolution inside a TLD crystal compound. The calculated profiles were implemented in the Randall-Wilkins equation to obtain the estimated glow curve. A number of jet temperature profiles were investigated in order to optimize the readout process. - Highlights: • The temperature profiles in a TLD chip compound were simulated. • Some non-routine heating profiles are proposed. • A better efficiency and shorter time can be obtained with these profiles. • The resulting glow curves were evaluated as well

  1. Personal neutron monitoring using TLD albedo combined with etched tracks detector

    Energy Technology Data Exchange (ETDEWEB)

    Tsujimura, N.; Momose, T. [Japan Nuclear Cycle Development Institute, Ibarakiken (Japan)

    2002-07-01

    The albedo dosimetry has been carried out in personal neutron monitoring in the MOX fuel plant of JNC Tokai Works, however, it has shortcomings mainly due to the inherently poor energy response. This paper describes our efforts to overcome these difficulties in practical use of albedo dosemeters. The following four subjects are presented: (1) the neutron energy response functions of albedo TLD obtained from the mono-energetic neutron irradiation experiments and the Monte-Carlo calculations, (2) the location- dependent correction factors calculated from the response functions and neutron energy spectra measured in the workplaces, (3) the results of the international personal neutron dosimetry intercomparison program, and (4) the operational comparison program of TLD albedo and etched tracks detector worn by workers engaged in the fabrication process of the MOX fuel plant. Finally, the characteristics of the combination neutron dosemeter using TLD albedo and solid state etched track detector are summarized.

  2. Program of TLD audits for quality control in radiotherapy

    International Nuclear Information System (INIS)

    Alvarez, P.; Feld, D.; Gomez, C.; Kessler, C.; Montano, R.G.; Lindner, C.; Peretti, M.; Saravi, M.; Miguez, V.; Paidon, S.; Raslawski, E.

    1998-01-01

    Full text: It is known that a high precision in radiotherapy is essential to ensure a successful radiation treatment. To reach this goal it is necessary to detect and minimise many errors, which can be done through a periodic program of quality control, not only internal checks but also participating in external audits that attempt to control the absorbed dose delivered and detect any source of error, coming from the machine itself or from human mistakes. Under the frame of the International Quality Assurance Network for Dosimetry in Radiotherapy proposed by the International Atomic Energy Agency, a National External Audit Group (EAG) has been created in our country, composed by the Secondary Standard Dosimetry Laboratory (SSDL), 2 Medical Physics and 1 Medical Radiotherapist. The SSDL and one of the Medical Physics belong to the National Atomic Energy Agency, meanwhile the rest of the group belong to the National Pediatric Hospital P rof. J.P.Garrahan . This EAG performs external audits to Radiation Therapy Centres with a thermoluminescence system, which is checked periodically by the IAEA. The audits are performed to the 60 Co γ-ray and high energy X-ray beams that are being used for medical application in the whole country. The SSDL is the responsible of the thermoluminescence measurements; deviation of the absorbed dose determined by the TLD system from the one informed by the Responsible of the Center within the interval ± 5% are considered acceptable while deviations out of this interval require the intervention of the Medical Physic Group and the Radiotherapist in order to determine the cause of the discrepancies. In 1997, 4 audits performed in reference conditions were carried out 68 60 Co units participated in the audits, 61 of them with deviation within the acceptable interval in their first participation, meanwhile 1 got this deviation in repeated audits, after the follow up performed by the Medical Physic Group. Regarding high energy X-ray beams

  3. Audit on dose delivery by using TLD in Radiotherapy Centers in Malaysia

    International Nuclear Information System (INIS)

    Md Saion Salikin; Taiman Kadni; Husaini Salleh; Asmaliza Hashim; Hasrul Husham Hussain

    2004-01-01

    The External Audit Group (EAQ) is established and supported by IAEA. Its main objective is to audit the accuracy of dose delivery to patients in radiotherapy centres or hospitals in developing countries in IAEA member states. At MINT the operation of EAG is managed by Medical Physics Group and supported by Secondary Standard Dosimetry Laboratory (SSDL), MINT. The selected radiotherapy centers are supplied with TLD powder in capsule form, to be irradiated with the required radiation doses, by their physicists. The irradiated TLD is analysed at SSDL. The result of the audit for a few radiotherapy centres in Malaysia, is presented in brief in this paper. (Author)

  4. Automated TLD systems: what can we expect from the market today?

    International Nuclear Information System (INIS)

    Duftschmid, K.E.; Strachotinsky, Ch.

    1990-01-01

    The personnel monitoring service at the Austrian Research Centre Seibersdorf, which presently handles some 16,000 dosemeters per month, has been operating for more than ten years with three automated TLD systems, Harshaw model 2271. In order to renew the instrumentation an extensive evaluation and comparison of four commercially available automated systems designed to the present state-of-the-art has been carried out. The test procedures included dosimetric performance, reliability, handling speed and throughput, and additional information such as glow curve evaluation etc. The results should provide useful advice to monitoring services interested in the application of modern automated TLD systems currently on the market. (author)

  5. A microcontroller based readout unit for a smart personnel monitoring TLD badge

    International Nuclear Information System (INIS)

    Gaonkar, U.P.; Kulkarni, M.S.; Kannan, S.

    1997-01-01

    An automated TLD personnel monitoring system is under development to cope up with the requirements of personnel monitoring of rapidly growing number of radiation workers. The core of the system is a smart TLD badge incorporating a memory device and a microcontroller based readout unit for reading the memory contents of the badge. The memory is used to store personnel data including the accumulated dose data. The reader unit has a serial RS 232C interface for connection to a PC for entering/modifying data in the memory. A password protected software has also been developed in C for entering/modifying the data in the single memory. 3 figs

  6. Skin dose measurements using MOSFET and TLD for head and neck patients treated with tomotherapy

    International Nuclear Information System (INIS)

    Kinhikar, Rajesh A.; Murthy, Vedang; Goel, Vineeta; Tambe, Chandrashekar M.; Dhote, Dipak S.; Deshpande, Deepak D.

    2009-01-01

    The purpose of this work was to estimate skin dose for the patients treated with tomotherapy using metal oxide semiconductor field-effect transistors (MOSFETs) and thermoluminescent dosimeters (TLDs). In vivo measurements were performed for two head and neck patients treated with tomotherapy and compared to TLD measurements. The measurements were subsequently carried out for five days to estimate the inter-fraction deviations in MOSFET measurements. The variation between skin dose measured with MOSFET and TLD for first patient was 2.2%. Similarly, the variation of 2.3% was observed between skin dose measured with MOSFET and TLD for second patient. The tomotherapy treatment planning system overestimated the skin dose as much as by 10-12% when compared to both MOSFET and TLD. However, the MOSFET measured patient skin doses also had good reproducibility, with inter-fraction deviations ranging from 1% to 1.4%. MOSFETs may be used as a viable dosimeter for measuring skin dose in areas where the treatment planning system may not be accurate.

  7. Calibration of TLD cards to beta ray spectra of 32P

    International Nuclear Information System (INIS)

    Ben-Shachar, B.; German, U.; Naim, E.

    1994-01-01

    The results of the evaluation of TLD chips are received in nC, and we need to transform these values to mGy, in order to obtain the penetrating and the non-penetrating dose. The calibration factors were determined experimentally by irradiation the TLD chips with an uranium source. Beta rays having other spectra can cause incorrect values when estimating the non-penetrating dose. If the spectrum of the beta source is known, a specific evaluation of the calibration factor can be performed. In this report, the estimation of the calibration factor for a 32 P source is presented. LiF:Ti,Mg TLD cards were irradiated calibrated source of 90 Sr/ 90 Y and 204 Tl and non-calibrated source of 32 P, in order to find the beta correction factor for the spectrum of 32 P. Calculations of the beta correction factor were performed too, by applying the Loevinger equations to the geometry of the TLD chips used in our routine measurements. The calculated values of the beta correction factors are lower than the experimental ones. When comparing the ratios, between the beta factors of 32 P and 90 Sr/ 90 Y received from the experiments and from the calculation, we found them to be constant up to ±5%. (authors) 15 refs, 2 figs, 6 tabs

  8. Development and extension of TLD audit in radiation therapy in the Czech Republic

    International Nuclear Information System (INIS)

    Valenta, J.; Ekendahl, D.

    2005-01-01

    A comprehensive and adequate quality assurance (QA) program is a crucial factor in minimizing gross errors and in reducing uncertainties caused during any of consecutive steps of radiation therapy process. Since 1997, the measuring centre of National Radiation Protection Institute in Prague (NRPI) has been performing TLD audit in external beam radiation therapy via mailed TL dosimeters, as a part of comprehensive QA program. The objective of TLD audit is to check dose delivery accuracy at radiation therapy centers and to inform the State Office for Nuclear Safety (SONS) on the situation. The flexibility of the method enables NRPI to inspect each centre at least once every two years. Compared with the EU average, situation in the Czech Republic seems to be similar. 95 % of measurements show deviation up to 5 % (97 % in the EQUAL network). Nevertheless, the acceptance level is stricter (3 %) in the Czech Republic. This is affordable because o(the small size of the country, and better ability to confirm the results promptly , if tolerance levels are exceeded. Still, 84 % of results meet the criteria of 3 %. Both basic and advanced modes of TLD audit may discover deviations in clinical dosimetry or in treatment planning for reference and non reference .conditions, although they do not provide enough data for proper interpretation of errors. The results show the importance of independent TLD audit as a flexible and operational part of the comprehensive quality assurance program. (authors)

  9. Operating experience of an automated TLD dispensing system at CORAL facility

    International Nuclear Information System (INIS)

    Ajoy, K.C.; Dhanasekaran, A.; Arun, R.; Yuvaraj, N.; Karthikeyan, D.; Dheeraj, R.; Akila, R.; Santhanam, R.; Rajagopal, V.; Kumar, Amudhu Ramesh

    2016-01-01

    Monitoring of exposures to occupational workers on individual basis is a regulatory requirement to demonstrate compliance that the dose to the workers is well within the dose limit. Over three decades for monitoring of external exposures, CaSO 4 based Thermo luminescence dosimeters (TLDs), which exhibit the required accuracy, reliability and ruggedness have been employed. TLD cards with unique identification number are loaded in plastic cassettes along with photographs are placed in wooden racks at the entry of the controlled area of the plant. However, there is always a chance that a TLD may be misplaced, used by others or there could be a deliberate act of misuse or abuse. To circumvent this it was decided to install an automated TLD dispensing system with individual TLD tracking as well as locking arrangement. CORAL reprocessing facility at IGCAR was the first to install one such system at Kalpakkam and the operating experience of the system for the last two years is brought out in this paper

  10. Skin dose measurements using MOSFET and TLD for head and neck patients treated with tomotherapy.

    Science.gov (United States)

    Kinhikar, Rajesh A; Murthy, Vedang; Goel, Vineeta; Tambe, Chandrashekar M; Dhote, Dipak S; Deshpande, Deepak D

    2009-09-01

    The purpose of this work was to estimate skin dose for the patients treated with tomotherapy using metal oxide semiconductor field-effect transistors (MOSFETs) and thermoluminescent dosimeters (TLDs). In vivo measurements were performed for two head and neck patients treated with tomotherapy and compared to TLD measurements. The measurements were subsequently carried out for five days to estimate the inter-fraction deviations in MOSFET measurements. The variation between skin dose measured with MOSFET and TLD for first patient was 2.2%. Similarly, the variation of 2.3% was observed between skin dose measured with MOSFET and TLD for second patient. The tomotherapy treatment planning system overestimated the skin dose as much as by 10-12% when compared to both MOSFET and TLD. However, the MOSFET measured patient skin doses also had good reproducibility, with inter-fraction deviations ranging from 1% to 1.4%. MOSFETs may be used as a viable dosimeter for measuring skin dose in areas where the treatment planning system may not be accurate.

  11. Environmental dosimetry system based on LiF : Mg, Ti (TLD-100)

    International Nuclear Information System (INIS)

    Saez Vergara, J.C.

    1990-01-01

    The report presents the various tests carried out to the characterize a thermoluminescence environmental dosimetry systems, using the phosphor LiF:mg,Ti (TLD-100) in chip form. The holder has been specifically designed in order to obtain simplicity in the operation and to assure correct measurements in terms of the new operational quantities in radiation protection (ICRU-1985). Some topics in TLD Environmental Monitoring are discussed (Dark Current, Reference Light, Zero Reading, Free-in-Air or Phantom Calibration, Fading Correction, Transit Dose, etc.), and the proposed solutions are exposed. The tests performed have been designed to conform with the different existing international Standards and Recommendations (ANSI : N545-1975; IEC: Draft 45B-1987, ISO : DP 8034-19849. The data from an European Interlaboratory Programm (EUR-8932) have been used to evaluate the performance : the TLD System presented is among the best systems using TLD-100. The results obtained in the characterization (linearity, repeatability, detection threshold, residue, angular response, stability of stored information, etc.) show the optimum performance of this dosimetric system in its application to environmental gamma dose monitoring. Based on these results, two operational procedures have been developed for the application of this Dosimetric System, specially in Quality Assurance Monitoring Programs around Nuclear Plants in Spain. (author)

  12. Electronic stability and reproducible accuracy of HARSHAW 2000(A,B) TLD-analyzer

    International Nuclear Information System (INIS)

    Yossef, S.K.; Henaish, B.A.

    1985-01-01

    Nowadays, the thermoluminescence techniques utilizing natural materials and assorted chemical compound of various geometrical configurations are widely and popularly used on the international scale as a dose evaluation system. The main problems which are usually encounting the accuracy of the evaluated dose by means of such various dosimeter forms are the long and short term stability of the measuring system. Also this manuscript is a very essential details stated out the principle mechanisms which cause that produced TL-readers instability. As it is stated out through the different sections of this issue, it is mainly due to the interior mechanisms of the TLD measuring systems. Further more, the various detailed discussions availed through the different sections of such issue are mainly accompanied by long term experiences gained by the authors. A novel heating cycle mechanism applied to HARSHOW 2000(A and b) TLD analyzer is tested experimentally. Also long and short term stability beside the reproducibility of the TLD reader system were experimentally tested under various seasonable environmental thermal conditions. The results of experimental measurements were noted for a total duration of six months during continuous operation of the TLD reader for one year. 1 fig., 3 tab

  13. Measurement of computed tomography dose profile with pitch variation using Gafchromic XR-QA2 and thermoluminescence dosimeter (TLD)

    Science.gov (United States)

    Purwaningsih, S.; Lubis, L. E.; Pawiro, S. A.; Soejoko, D. S.

    2016-03-01

    This research was aimed to check the patterns of dose profile on adult and pediatric head scan. We compared measurement result on dose profile along the z- axis rotation at peripheries and center phantom with a variety of pitch, i.e. 0.75, 1, 1.5 for adult and pediatric head protocol, keeping the rest of the scan parameters constant. Measurements were performed on homogeneous, cylindrical PMMA phantom with diameters of 16 and 10 cm using XR-QA2 Gafchromic film and TLD as dosimeters. The measurement result indicated a decrease in the dose about 50% and 47% for adult and pediatric head scan with the increase of pitch. For 0.75 value of pitch adult head scan, dose range for each position were (2.4 - 5.0) cGy, (3.1 - 5.3) cGy, (2.2 - 4.5) cGy, (2.8 - 5.3) cGy, and (3.3 - 5.6) cGy for position of center, 3, 6, 9 and 12 o'clock peripheral phantom position respectively. Dose profile for adult and pediatric head scan protocols has pattern curve with the maximum dose in the middle and tendency of symmetry near the edges, with different the plateau length along z- axis direction in accordance to the measurement position in the phantom.

  14. TLD Intercomparison in accelerators for radiotherapy in three Latin american countries

    International Nuclear Information System (INIS)

    Gaona, E.; Azorin N, J.; Perez, M.A.; Picon, C.; Castellanos, E.; Plazas, M.C.; Murcia, G.; Archundia, L.

    1998-01-01

    In Radiotherapy one of the objectives is to establish and to give follow up to quality assurance programs which make sure that the doses administered to the patients with cancer are a high probability of a success in external radiation. Likewise, one of the present preoccupations of the United Nations Agencies as well as the International Atomic Energy Agency and the Pan-American Health Organization is the optimal employment of the radiations in the treatment of cancer patients since the administered dose in Radiotherapy suffers considerable variations by the lack of quality assurance programs. The use of Electron linear accelerators requires a program of quality assurance that includes expert personnel, equipment and adequate facilities. The more used methodology for the dosimetry calibration and characterization of X-ray beams and high energy electrons for radiotherapy use is using a ionization chamber dosemeter calibrated in a regional secondary standardization laboratory. However, to establish and give follow up to the quality assurance programs it is necessary the dosimetric intercomparison through TLD. In this study it was designed plastic phantoms with TLD crystals and it was made its characterization to realize an absorbed dose analysis in the crystals exposed at X-ray beams 6 MV and high energy electrons 10 and 12 MeV to standardize the dosimetric procedures and proceeding to realize an International Pilot intercomparison of absorbed doses in TLD crystals in three Latin American countries: Mexico, Peru and Colombia with the participation of accelerators of five different institutions. The found results show that the majority of the measured doses with TLD in the different accelerators were in the 0.95-1.05 range though it had two cases outside of this range. The use of the phantoms with TLD crystals shows that they are of excellent aid to make analysis of the doses administered to the patients and an intercomparison of results to standardize procedures at

  15. A Computerized QC Analysis of TLD Glow Curves for Personal Dosimetry Measurements Using Tag QC Program

    International Nuclear Information System (INIS)

    Primo, S.; Datz, H.; Dar, A.

    2014-01-01

    The External Dosimetry Lab (EDL) at the Radiation Safety Division at Soreq Nuclear Research Center (SNRC) is ISO 17025 certified and provides its services to approximately 13,000 users throughout the country from various sectors such as medical, industrial and academic. About 95% of the users are monitored monthly for X-rays, radiation using Thermoluminescence Dosimeter (TLD) cards that contain three LiF:Mg,Ti elements and the other users, who work also with thermal neutrons, use TLD cards that contain four LiF:Mg,Ti elements. All TLD cards are measured with the Thermo 8800pc reader. Suspicious TLD glow curve (GC) can cause wrong dose estimation so the EDL makes great efforts to ensure that each GC undergoes a careful QC procedure. The current QC procedure is performed manually and through a few steps using different softwares and databases in a long and complicated procedure: EDL staff needs to export all the results/GCs to be checked to an Excel file, followed by finding the suspicious GCs, which is done in a different program (WinREMS), According to the GC shapes (Figure 1 illustrates suitable and suspicious GC shapes) and the ratio between the elements result values, the inspecting technician corrects the data. The motivation for developing the new program is the complicated and time consuming process of our the manual procedure to the large amount of TLDs each month (13,000), similarly to other Dosimetry services that use computerized QC GC analysis. it is important to note that only ~25% of the results are above the EDL recorded level (0.10 mSv) and need to be inspected. Thus, the purpose of this paper is to describe a new program, TagQC, which allows a computerized QC GC analysis that identifies automatically, swiftly, and accurately suspicious TLD GC

  16. Comparative study on skin dose measurement using MOSFET and TLD for pediatric patients with acute lymphatic leukemia.

    Science.gov (United States)

    Al-Mohammed, Huda I; Mahyoub, Fareed H; Moftah, Belal A

    2010-07-01

    The object of this study was to compare the difference of skin dose measured in patients with acute lymphatic leukemia (ALL) treated with total body irradiation (TBI) using metal oxide semiconductor field-effect transistors (mobile MOSFET dose verification system (TN-RD-70-W) and thermoluminescent dosimeters (TLD-100 chips, Harshaw/ Bicron, OH, USA). Because TLD has been the most-commonly used technique in the skin dose measurement of TBI, the aim of the present study is to prove the benefit of using the mobile MOSFET (metal oxide semiconductor field effect transistor) dosimeter, for entrance dose measurements during the total body irradiation (TBI) over thermoluminescent dosimeters (TLD). The measurements involved 10 pediatric patients ages between 3 and 14 years. Thermoluminescent dosimeters and MOSFET dosimetry were performed at 9 different anatomic sites on each patient. The present results show there is a variation between skin dose measured with MOSFET and TLD in all patients, and for every anatomic site selected, there is no significant difference in the dose delivered using MOSFET as compared to the prescribed dose. However, there is a significant difference for every anatomic site using TLD compared with either the prescribed dose or MOSFET. The results indicate that the dosimeter measurements using the MOSFET gave precise measurements of prescribed dose. However, TLD measurement showed significant increased skin dose of cGy as compared to either prescribed dose or MOSFET group. MOSFET dosimeters provide superior dose accuracy for skin dose measurement in TBI as compared with TLD.

  17. Comparison of neutron dose measured by Albedo TLD and etched tracks detector at PNC plutonium fuel facilities

    International Nuclear Information System (INIS)

    Tsujimura, N.; Momose, T.; Shinohara, K.; Ishiguro, H.

    1996-01-01

    Power Reactor and Nuclear Fuel Development Corporation (PNC) has fabricated Plutonium and Uranium Mixed OXide (MOX) fuel for FBR MONJU at Tokai works. In this site, PNC/Panasonic albedo TLDs/1/ are used for personnel neutron monitoring. And a part of workers wore Etched Tracks Detector (ETD) combined with TLD in order to check the accuracy of the neutron dose estimated by albedo TLD. In this paper, the neutron dose measured by TLD and ETD in the routine monitoring is compared at PNC plutonium fuel facilities. (author)

  18. Pilot study: relative dose of the TLD, OSL and Radiochromic film applied in CT exams dosimetry

    International Nuclear Information System (INIS)

    Kikuti, C.F.; Maia, R.S.I.; Romano, R.F.T.; Daros, K. A.C.

    2015-01-01

    At DDI/UNIFESP, the abdomen and chest CT exams correspond to 38% of the exams, becoming the focus of studies. The aim of this study is to assess the relative dose using TLDs, OSLs and RF for the evaluation of the dose distribution in the skin in abdomen CT exams. The simulation of the CT exam was performed in an anthropomorphic phantom, using a CT scanner Philips, Brilliance/64 and TLDs, OSLs and RF fixed along the sagittal axis of the phantom. The OSLs showed similar performance to the TLDs and RF shows low accuracy, resulting in an average value (0.927±0.022). (author)

  19. Pilot study: relative dose of the TLD, OSL and Radiochromic film applied in CT exams dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Kikuti, C.F. [Universidade Federal do Mato Grosso do Sul (UFMS), Campo Grande, MS (Brazil). Hospital Universitario Maria Aparecida Pedrossian; Maia, R.S.I.; Romano, R.F.T.; Daros, K. A.C., E-mail: daros.kellen@unifesp.br [Universidade Federal de Sao Paulo (UNIFESP), Sao Paulo, SP (Brazil). Escola Paulista de Medicina. Departamento de Diagnostico por Imagem

    2015-07-01

    At DDI/UNIFESP, the abdomen and chest CT exams correspond to 38% of the exams, becoming the focus of studies. The aim of this study is to assess the relative dose using TLDs, OSLs and RF for the evaluation of the dose distribution in the skin in abdomen CT exams. The simulation of the CT exam was performed in an anthropomorphic phantom, using a CT scanner Philips, Brilliance/64 and TLDs, OSLs and RF fixed along the sagittal axis of the phantom. The OSLs showed similar performance to the TLDs and RF shows low accuracy, resulting in an average value (0.927±0.022). (author)

  20. Vivo dosimetry using TLD detectors in prostate seed implants of I-125: preliminary results; Dosimetria in vivo mediante detectores de TLD en implantes de prostata con semillas de I-125: resultados preliminares

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Reyes, A.; Pedro, A.; Bassas, P.; Duch, M. A.; Cros, M.; Mane, S.

    2011-07-01

    We present preliminary results of a new in vivo dosimetry technique that could allow to know immediately after implantation of the prostate if the dose distribution determined by the scheduler is similar to the actual dose measured with TLD detectors.

  1. Thermoluminescent relative efficiencies of TLD-100 for nitrogen ions respect of gamma radiation; Eficiencias termoluminiscentes relativas de TLD-100 para iones de nitrogeno respecto de radiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Concha S, K. [UNAM, Facultad de Ciencias, 04510 Mexico D.F. (Mexico); Avila, O. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Gamboa de Buen, I. [ICN-UNAM, 04510 Mexico D.F. (Mexico); Rodriguez V, M.; Buenfil, A.E.; Ruiz T, C.; Brandan, M.E. [IFUNAM, 04510 Mexico D.F. (Mexico)

    2004-07-01

    The purpose of this work is to measure the thermoluminescent relative efficiency of those TLD-100 dosemeters irradiated with nitrogen ions with respect to the gamma radiation of {sup 60} Co, in function of the linear energy transfer (LET). Two energy of such nitrogen ions were selected that has the same value from LET when impacting in the dosemeters but with E{sub 1} energy (4.8 MeV) and E{sub 2} (9.95 MeV) smaller and greater respectively that the energy of the Bragg peak. (Author)

  2. Effects of phosphor proportion and grain size on photon energy response of CaSO4:Dy teflon TLD discs

    International Nuclear Information System (INIS)

    Pradhan, A.S.; Bhatt, R.C.

    1979-01-01

    Effects of phosphor proportion and grain size on the photon energy dependence of CaSO 4 :Dy embedded teflon TLD discs have been studied. It was found that in the commonly used TLD disc compositions, the proportion of phosphor has only little effect on energy dependence. This dependence could be significantly reduced by using phosphor of grain size less than 1 μm. The experimental results are compared with calculated results. (Auth.)

  3. Impact of ANSI 2009 criteria for performance testing in TLD personnel monitoring

    International Nuclear Information System (INIS)

    MeenaI, P.; Rakesh, R.B.; Srivastava, Kshama; KoIambe, D.H.; Sapra, B.K.

    2014-01-01

    External Quality Assurance in TLD Personnel Monitoring Service was initiated in 1985, for periodic performance evaluation of various TLD Laboratories through postal exercise. Presently, all the 16 laboratories involved in Personnel Monitoring Service are covered under QA exercise. Since beginning, American National Standards Institute (ANSI) criteria have been adopted for performance testing in QA exercise. Presently, ANSI 2001 performance criteria along with ISO trumpet curve analysis method are being used for performance evaluation. In 2009, ANSI modified the performance evaluation criteria and this study evaluates its impact and feasibility of implementation of ANSI 2009 criteria in the quality assurance program for personnel monitoring. The performance of some laboratories evaluated using both ANSI 2001 and ANSI 2009 criteria have been discussed. The study shows that the ANSI 2009 criteria is more stringent and encourages even distribution of bias and standard deviation. This can be implemented with suitable modifications for performance evaluation

  4. Fast neutron responses of CaF2:Tm Teflon TLD discs of different thicknesses

    International Nuclear Information System (INIS)

    Pradhan, A.S.; Hoffmann, W.

    1986-01-01

    The fact that in CaF 2 :Tm (TLD-300) the ratio of the heights of thermoluminescence (TL) glow peaks at 240 0 C and 150 0 C is greater for irradiations by high LET radiations than by gamma rays has been found useful for the simultaneous and separate measurement of fast neutron and gamma ray absorbed doses. A recent study has indicated that the mixed field dosimetric characteristics of CaF 2 :Tm could be significantly improved by using thin TLDs. In the present study, CaF 2 :Tm Teflon TLD discs of thickness as low as 0.05 mm were evaluated. The thin discs could be read out by using normal planchette heating if a 400 0 C heat treatment is given to the discs prior to irradiation and TL readout. Influence of encapsulation of thin dosemeters was studied and their utility in situations such as interface dosimetry is discussed. (author)

  5. Pattern check of TLD disc readings - an important tool to identify abnormal conditions in workplace

    International Nuclear Information System (INIS)

    Pradhan, S.M.; Sneha, C.; Bhattacharya, M.; Sahai, M.K.; Pradeep, Ratna; Datta, D.; Bhatnagar, Amit

    2016-01-01

    Personnel monitoring for external radiation using CaSO 4 :Dy based TLD badge is well established in Indian radiation protection program. TLD badge enables evaluation of occupational dose based on the pattern and values of the three disc readings. Different patterns of disc readings are obtained depending on the type and energy of radiation in the workplace. Pattern not conforming to the radiation in the workplace also called as improper pattern can be a useful tool for investigation of any deviation / abnormality in workplace or monitoring practices. The paper presents different examples of improper pattern observed in monitoring that has helped to find out the deviations in the workplace or monitoring practices. Results of the experiments conducted to simulate some of the observed pattern are also presented in the paper

  6. The Dependence of the Dose Response Supralinearity of Peak 5 in TLD-100 on Recombination Temperature

    International Nuclear Information System (INIS)

    Horowitz, Y.S.; Satinger, D.; Oster, L.

    1999-01-01

    Isothermal readout of LiF:Mg,Ti (TLD-700) has recently been used to study the dependence of the supralinearity of peak 5 on recombination temperature. The results were interpreted to be in conflict with earlier results which investigated the effect of readout heating rate on the supralinearity of peak 5 in TLD-100. In this work the two experiments are inspected in greater detail. It is illustrated that the isothermal decay data is not in conflict with the heating rate data. However, the heating rate results do apparently indicate a strong transition in the temperature dependence of the relative strengths of the recombination and competitive cross sections at approximately 235 deg. C, which requires further study and analysis. (author)

  7. Adequacy of annealing duration in reducing the background counts of personnel monitoring TLD cards - a study

    International Nuclear Information System (INIS)

    Srivastava, Kshama; Varadharajan, Geetha; Punekar, M.P.; Chougaokar, M.P.; Ayappan, P.

    2010-01-01

    In India, the personnel monitoring service of ∼ 70,000 radiation workers is being provided using indigenously developed TLD system comprising three CaSO 4 :Dy embedded Teflon discs. In order to remove TL and reset the distribution of defects/trapping centres, all TLD cards are subjected to an annealing treatment at elevated temperature prior to their next use. As per the standardized protocol annealing is carried out in a hot air circulating oven at 230 deg C for 4 hr, which is sufficient to reset the TL dosemeters for dose levels upto 100 mSv. In order to verify the appropriateness of annealing procedures adopted by the Laboratory, a detailed study was conducted using four sets of cards namely A, B, C and D series, exposed to various dose levels

  8. Further characteristics important in the operation of ceramic BeO TLD

    International Nuclear Information System (INIS)

    Gammage, R.B.

    1977-01-01

    There is now a considerable volume of published research dealing with ceramic BeO--TLD (Crase and Gammage, 1975; Yamashita et al., 1974; Scarpa et al., 1971). Its high sensitivity to radiation (1 mR), cheapness, commercial availability, non-toxicity, chemical stability, an atomic number of near tissue equivalence, and resistance to thermal fading, suggest that it should, by now, have found widespread acceptance as a TLD phosphor. It has not. There are only a small handful of reports dealing with the practical application of this type of dosimeter (Puite et al., 1974; Gammage and Haywood, 1976; Gesell et al., 1975). It seems wise, therefore, to look at the phosphor more closely and to focus on characteristics likely to cause problems under real operating conditions, especially those which are acting as a deterrent to its widespread acceptance. Operational characteristics were studied and the results are discussed

  9. PorTL - a compact, portable TLD reader for environmental and personal dosimetry

    International Nuclear Information System (INIS)

    Deme, S.; Apathy, I.; Bodnar, L.; Csoke, A.; Feher, I.; Pazmandi, T.

    2005-01-01

    Thermoluminescent dosimeters (TLDs) are commonly used for environmental monitoring, for personal and medical dosimetry, for dosimetry in nuclear facilities, etc. Major advantages are their independence of the power supply, small dimension, sensitivity, good stability, wide measuring range, resistance to environmental changes and relatively low cost. The disadvantage is that the detector must be transported for evaluation to a laboratory equipped with a large, heavy and expensive TLD Reader operated by qualified personnel, which considerably increases the costs and delays results. To overcome this disadvantage, the KFKI Atomic Energy Research Institute (KFKI AEKI), in co-operation with BL Electronics (Hungary), has developed a new and unique TLD system containing a small, portable, battery powered and moderate-price reader for commercial use. This paper gives a detailed description and parameters of this system.(author)

  10. Verification or treatment planning system of radiotherapy using TLD-100; Verificacion de los sistemas de planificacion de tratamiento de radioterapia empleando TLD-100

    Energy Technology Data Exchange (ETDEWEB)

    Pinuela, J., E-mail: jcpinuela@hotmail.co [Hospital Central de Maracay (Venezuela, Bolivarian Republic of). Servicio de Radioterapia

    2010-07-01

    The evaluation of the treatment planning system (TPS) used in radiotherapy Precise Plan, was carried out using TLD-100 dosimeters, comparing the dose obtained with an ionization chamber. The TLD-100 were calibrated using secondary standard of SSDL, selecting dosimeters which had a standard deviation less than 1% for dosimeter calibration and less than 5% for dosimeter of field, for the tests conducted in TPS, The Alderson Phantom was used to evaluate the wedge and bolus, and Lucy 3D allowed us to evaluate correspondence of CT numbers, volume expansion, beam shaping, precise dose and beam weigh assignment. It was observed that the results of Lucy 3D were within the values expected except the volume expansion process with more than 10% difference, the evaluation of beam modulators systems with wedges and bolus as beam shaping yielded values within the expected with variations less than 5% and to assess the supply of specific doses, it was observed that the values obtained were precise and accurate since the same variation was less than 0.5% for the test. The importance of assessing the TPS lies in our country there is no procedure to verify that system and these tests provide a basis for future comparisons. (author)

  11. Measurement of high natural background radiation levels by TLD at Cox's Bazar coastal areas in Bangladesh

    International Nuclear Information System (INIS)

    Mollah, A.S.; Rahman, M.M.; Koddus, M.A.; Husain, S.R.; Malek, M.A.

    1987-01-01

    High natural background radiation levels at the Cox's Bazar coastal areas in Bangladesh were measured by LiF (TLD-100) dosemeters. The dose rates varied from 2621 to 35391 μGy.y -1 with a mean of 11968 μGy.y -1 . The average dose rate is found to significantly higher than the world average value. In order to formulate appropriate guidelines for radiation protection of the population in this area, the necessary recommendations are described. (author)

  12. Performance testing of the environmental TLD system for the Three Mile Island Nuclear Station.

    Science.gov (United States)

    Toke, L F; Carson, B H; Baker, G G; McBride, M H; Plato, P A; Miklos, J A

    1984-05-01

    Panasonic UD-801 thermoluminescent dosimeters ( TLDs ) containing two calcium sulfate phosphors were tested under Performance Specification 3.1 established by the American National Standard Institute ( ANSI75 ) and in the U.S. Nuclear Regulatory Commission's Regulatory Guide 4.13 ( NRC77 ). The specific qualifying tests included TLD uniformity, reproducibility, energy dependence and directional dependence. The overall measurement uncertainties and associated confidence levels are within the prescribed guidelines defined in the qualifying requirements for environmental TLDs .

  13. Evaluation of LiF:Mg,Ti (TLD-100 for Intraoperative Electron Radiation Therapy Quality Assurance.

    Directory of Open Access Journals (Sweden)

    Raffaele Liuzzi

    Full Text Available Purpose of the present work was to investigate thermoluminescent dosimeters (TLDs response to intraoperative electron radiation therapy (IOERT beams. In an IOERT treatment, a large single radiation dose is delivered with a high dose-per-pulse electron beam (2-12 cGy/pulse during surgery. To verify and to record the delivered dose, in vivo dosimetry is a mandatory procedure for quality assurance. The TLDs feature many advantages such as a small detector size and close tissue equivalence that make them attractive for IOERT as in vivo dosimeters.LiF:Mg,Ti dosimeters (TLD-100 were irradiated with different IOERT electron beam energies (5, 7 and 9 MeV and with a 6 MV conventional photon beam. For each energy, the TLDs were irradiated in the dose range of 0-10 Gy in step of 2 Gy. Regression analysis was performed to establish the response variation of thermoluminescent signals with dose and energy.The TLD-100 dose-response curves were obtained. In the dose range of 0-10 Gy, the calibration curve was confirmed to be linear for the conventional photon beam. In the same dose region, the quadratic model performs better than the linear model when high dose-per-pulse electron beams were used (F test; p<0.05.This study demonstrates that the TLD dose response, for doses ≤10 Gy, has a parabolic behavior in high dose-per-pulse electron beams. TLD-100 can be useful detectors for IOERT patient dosimetry if a proper calibration is provided.

  14. Response of TLD-albedo and nuclear track dosimeters exposed to plutonium sources

    International Nuclear Information System (INIS)

    Brackenbush, L.W.; Baumgartner, W.V.; Fix, J.J.

    1991-12-01

    Neutron dosimetry has been extensively studied at Hanford since the mid-1940s. At the present time, Hanford contractors use thermoluminescent dosimeter (TLD)-albedo dosimeters to record the neutron dose equivalent received by workers. The energy dependence of the TLD-albedo dosimeter has been recognized and documented since introduced at Hanford in 1964 and numerous studies have helped assure the accuracy of dosimeters. With the recent change in Hanford's mission, there has been a significant decrease in the handling of plutonium tetrafluoride, and an increase in the handling of plutonium metal and plutonium oxide sources. This study was initiated to document the performance of the current Hanford TLD-albedo dosimeter under the low scatter conditions of the calibration laboratory and under the high scatter conditions in the work place under carefully controlled conditions at the Plutonium Finishing Plant (PFP). The neutron fields at the PFP facility were measured using a variety of instruments, including a multisphere spectrometer, tissue equivalent proportional counters, and specially calibrated rem meters. Various algorithms were used to evaluate the TLD-albedo dosimeters, and the results are given in this report. Using current algorithms, the dose equivalents evaluated for bare sources and sources with less than 2.5 cm (1 in.) of acrylic plastic shielding in high scatter conditions typical of glove box operations are reasonably accurate. Recently developed CR-39 track etch dosimeters (TEDs) were also exposed in the calibration laboratory and at the PFP. The results indicate that the TED dosimeters are quite accurate for both bare and moderated neutron sources. Until personnel dosimeter is available that incorporates a direct measure of the neutron dose to a person, technical uncertainties in the accuracy of the recorded data will continue

  15. Response of TLD-albedo and nuclear track dosimeters exposed to plutonium sources

    Energy Technology Data Exchange (ETDEWEB)

    Brackenbush, L.W.; Baumgartner, W.V.; Fix, J.J.

    1991-12-01

    Neutron dosimetry has been extensively studied at Hanford since the mid-1940s. At the present time, Hanford contractors use thermoluminescent dosimeter (TLD)-albedo dosimeters to record the neutron dose equivalent received by workers. The energy dependence of the TLD-albedo dosimeter has been recognized and documented since introduced at Hanford in 1964 and numerous studies have helped assure the accuracy of dosimeters. With the recent change in Hanford`s mission, there has been a significant decrease in the handling of plutonium tetrafluoride, and an increase in the handling of plutonium metal and plutonium oxide sources. This study was initiated to document the performance of the current Hanford TLD-albedo dosimeter under the low scatter conditions of the calibration laboratory and under the high scatter conditions in the work place under carefully controlled conditions at the Plutonium Finishing Plant (PFP). The neutron fields at the PFP facility were measured using a variety of instruments, including a multisphere spectrometer, tissue equivalent proportional counters, and specially calibrated rem meters. Various algorithms were used to evaluate the TLD-albedo dosimeters, and the results are given in this report. Using current algorithms, the dose equivalents evaluated for bare sources and sources with less than 2.5 cm (1 in.) of acrylic plastic shielding in high scatter conditions typical of glove box operations are reasonably accurate. Recently developed CR-39 track etch dosimeters (TEDs) were also exposed in the calibration laboratory and at the PFP. The results indicate that the TED dosimeters are quite accurate for both bare and moderated neutron sources. Until personnel dosimeter is available that incorporates a direct measure of the neutron dose to a person, technical uncertainties in the accuracy of the recorded data will continue.

  16. Response of TLD-albedo and nuclear track dosimeters exposed to plutonium sources

    Energy Technology Data Exchange (ETDEWEB)

    Brackenbush, L.W.; Baumgartner, W.V.; Fix, J.J.

    1991-12-01

    Neutron dosimetry has been extensively studied at Hanford since the mid-1940s. At the present time, Hanford contractors use thermoluminescent dosimeter (TLD)-albedo dosimeters to record the neutron dose equivalent received by workers. The energy dependence of the TLD-albedo dosimeter has been recognized and documented since introduced at Hanford in 1964 and numerous studies have helped assure the accuracy of dosimeters. With the recent change in Hanford's mission, there has been a significant decrease in the handling of plutonium tetrafluoride, and an increase in the handling of plutonium metal and plutonium oxide sources. This study was initiated to document the performance of the current Hanford TLD-albedo dosimeter under the low scatter conditions of the calibration laboratory and under the high scatter conditions in the work place under carefully controlled conditions at the Plutonium Finishing Plant (PFP). The neutron fields at the PFP facility were measured using a variety of instruments, including a multisphere spectrometer, tissue equivalent proportional counters, and specially calibrated rem meters. Various algorithms were used to evaluate the TLD-albedo dosimeters, and the results are given in this report. Using current algorithms, the dose equivalents evaluated for bare sources and sources with less than 2.5 cm (1 in.) of acrylic plastic shielding in high scatter conditions typical of glove box operations are reasonably accurate. Recently developed CR-39 track etch dosimeters (TEDs) were also exposed in the calibration laboratory and at the PFP. The results indicate that the TED dosimeters are quite accurate for both bare and moderated neutron sources. Until personnel dosimeter is available that incorporates a direct measure of the neutron dose to a person, technical uncertainties in the accuracy of the recorded data will continue.

  17. Assessment of radiation exposure of nuclear medicine staff using personal TLD dosimeters and charcoal detectors

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, F.; Garcia-Talavera, M.; Pardo, R.; Deban, L. [Valladolid Univ., Dept. de Quimica Analitica, Facultad de Ciencias (Spain); Garcia-Talavera, P.; Singi, G.M.; Martin, E. [Hospital Clinico Univ., Servicio de Medicina Nuclear, Salamanca (Spain)

    2006-07-01

    Although the main concern regarding exposure to ionizing radiation for nuclear medicine workers is external radiation, inhalation of radionuclides can significantly contribute to the imparted doses. We propose a new approach to assess exposure to inhalation of {sup 131}I based on passive monitoring using activated charcoal detectors. We compared the inhalation doses to the staff of a nuclear medicine department, based on the measurements derived from charcoal detectors placed at various locations, and the external doses monitored using personal TLD dosimeters. (authors)

  18. Assessment of radiation exposure of nuclear medicine staff using personal TLD dosimeters and charcoal detectors

    International Nuclear Information System (INIS)

    Jimenez, F.; Garcia-Talavera, M.; Pardo, R.; Deban, L.; Garcia-Talavera, P.; Singi, G.M.; Martin, E.

    2006-01-01

    Although the main concern regarding exposure to ionizing radiation for nuclear medicine workers is external radiation, inhalation of radionuclides can significantly contribute to the imparted doses. We propose a new approach to assess exposure to inhalation of 131 I based on passive monitoring using activated charcoal detectors. We compared the inhalation doses to the staff of a nuclear medicine department, based on the measurements derived from charcoal detectors placed at various locations, and the external doses monitored using personal TLD dosimeters. (authors)

  19. TLD gamma-ray energy deposition measurements in the zero energy fast reactor ZEBRA

    International Nuclear Information System (INIS)

    Knipe, A.D.

    1977-01-01

    A recent study of gamma-ray energy deposition was carried out in the Zebra reactor at AEE Winfrith during a collaborative programme between the UKAEA and PNC of Japan. The programme was given the title MOZART. This paper describes the TLD experiments in the MOZART MZB assembly and discusses the technique and various corrections necessary to relate the measured quantity to the calculated energy deposition

  20. Measurement of exposure dose rate by TLD in 60Co garden

    International Nuclear Information System (INIS)

    Fan Chengfang; Li Pinfang; Wu Maoliang; Zhao Quan

    1987-01-01

    The use of TLD method to measure exposure dose rate in 60 Co garden is described. As compared with chemical dosimetry, the relative deviation of measurement would not exceed 10%. The good repeatability has been proved by comparing the measurements of different times and distances with correction of decay law and 1/1 2 law. Besides, the distribution of exposure dose rate was influenced by scattering of the living plants

  1. NRPB TLD and dose record keeping service - further progress

    International Nuclear Information System (INIS)

    Greenslade, E.

    1979-01-01

    Various aspects of the National Radiological Protection Board's service are described. An increasing number of UK employers are transferring from film monitors, and record keeping is now provided for both large and small groups of workers. Data entry directly from punched cards prepared by the larger employers has reduced initial costs and therefore carries a reduced registration fee for these users. Computerized dose record keeping allows automatic retrieval of cumulative dose information from any NRPB record of previous employment, thus safeguarding itinerant workers. Warning Dose Reports are issued automatically when cumulative dose totals reach or exceed 60% of a limit, or when a dose rate greater than 0.1 rem per 4 weeks is recorded. Flexibility in wearing period results in dosemeter economy and reduces laboratory work load. High recorded doses can be checked by UV stimulation of both disks to confirm the accuracy of the previous measurement. Employers are provided with a comprehensive and accurate monitoring package, fulfilling HSE requirements and exempting employers from their former responsibility to keep their own comprehensive records. (UK)

  2. The evaluation of dose of TSEI with TLD and diode detector of the uterine cervix cancer

    International Nuclear Information System (INIS)

    Je, Young Wan; Na, Keyung Su; Yoon, Il Kyu; Park, Heung Deuk

    2005-01-01

    To evaluate radiation dose and accuracy with TLD and diode detector when treat total skin with electron beam. Using Stanford Technique, we treated patient with Mycosis Fungoides. 6 MeV electron beam of LINAC was used and the SSD was 300 cm. Also, acrylic speller(0.8 cm) was used. The patient position was 6 types and the gantry angle was 64, 90 and 116 degree. The patient's skin dose and the output were detected 5 to 6 times with TLD and diode. The deviations of dose detected with TLD from tumor dose were CA + 6%, thigh + 8%, umbilicus + 4%, calf - 8%, vertex - 74.4%, deep axillae - 10.2%, anus and testis - 87%, sole - 86% and nails shielded with 4 mm lead + 4%. The deviations of dose detected with diode were - 4.5% ∼ + 5% at the patient center and - 1.1% ∼ + 1% at the speller. The deviation of total skin dose was + 8% ∼ - 8% and that deviation was within the acceptable range(±10%). The boost dose was irradiated for the low dose areas(vertex, anus, sole). The electron beam output detected at the sootier was stable. It is thought that the deviation of dose at patient center detected with diode was induced by detection point and patient position.

  3. Comparative study of trapping parameters of LiF(TLD-100) from different production batches

    Energy Technology Data Exchange (ETDEWEB)

    Bos, A.J.J.; Piters, T.M.; Vries, W. de; Hoogenboom, J.E. (Delft Univ. of Technology (Netherlands). Interfaculty Reactor Institute)

    1990-01-01

    Computerised glow curve analysis has been used to determine the trapping parameters of the main peaks of the thermoluminescent (TL) material LiF(TLD-100). The TL material (solid state chips) originated from six different production batches with at least 19 chips per batch. The maxima of glow peaks 2 to 5 are found at the same temperature within very small limits. The activation energy and frequency factor of the main glow peak (peak 5) of TLD-100 originating from two batches differ significantly from those of the other four investigated batches. Nevertheless, the sensitivity of glow peak 5 is more or less the same for all batches. The trapping parameters of glow peaks 2 to 4 of TLD-100 vary little from batch to batch. The measured half-life of peak 2 differed strongly from batch to batch. For all investigated peaks no correlation has been found between glow peak sensitivity and trapping parameters. The results of this study suggest that both defect concentration and nature of the trapping centres vary from batch to batch. It would appear that as a consequence of selection by the manufacturer, the differences between the batches in terms of total light output are small. (author).

  4. Quality control of the breast cancer treatments on Hdr brachytherapy with TLD-100

    Energy Technology Data Exchange (ETDEWEB)

    Torres H, F. [Universidad de Cordoba, Materials and Applied Physics Group, 230002 Monteria, Cordoba (Colombia); De la Espriella V, N. [Universidad de Cordoba, Grupo Avanzado de Materiales y Sistemas Complejos, 230002 Monteria, Cordoba (Colombia); Sanchez C, A., E-mail: franciscotorreshoyos@yahoo.com [Universidad de Cordoba, Departamento de Enfermeria, 230002 Monteria, Cordoba (Colombia)

    2014-07-01

    An anthropomorphic Phantom, a female trunk, was built with a natural bone structure and experimental material coated, glycerin and water-based material called JJT to build soft tissue equivalent to the muscle of human tissue, and a polymer (styrofoam) to build the lung as critical organ to simulate the treatment of breast cancer, with high dose rate brachytherapy (Hdr) and sources of Ir-192. The treatments were planned and calculated for the critical organ: Lung, and injury of 2 cm in diameter in breast with Micro Selectron Hdr system and the software Plato Brachytherapy V 14.1 of the Nucletron (Netherlands) which uses the standard protocol of radiotherapy for brachytherapy treatments. The dose experimentally measured with dosimeters TLD-100 LiF: Mg; Ti, which were previously calibrated, were placed in the same positions and bodies mentioned above, with less than 5% uncertainty. The reading dosimeters was carried out in a Harshaw TLD 4500. The results obtained for calculated treatments, using the standard simulator, and the experimental with TLD-100, show a high concordance, as they are on average a ± 1.1% making process becomes in a quality control of this type of treatments. (Author)

  5. Application of Glow Curve Deconvolution Method to Evaluate Low Dose TLD LiF

    International Nuclear Information System (INIS)

    Kurnia, E; Oetami, H R; Mutiah

    1996-01-01

    Thermoluminescence Dosimeter (TLD), especially LiF:Mg, Ti material, is one of the most practical personal dosimeter in known to date. Dose measurement under 100 uGy using TLD reader is very difficult in high precision level. The software application is used to improve the precision of the TLD reader. The objectives of the research is to compare three Tl-glow curve analysis method irradiated in the range between 5 up to 250 uGy. The first method is manual analysis, dose information is obtained from the area under the glow curve between pre selected temperature limits, and background signal is estimated by a second readout following the first readout. The second method is deconvolution method, separating glow curve into four peaks mathematically and dose information is obtained from area of peak 5, and background signal is eliminated computationally. The third method is deconvolution method but the dose is represented by the sum of area of peak 3,4 and 5. The result shown that the sum of peak 3,4 and 5 method can improve reproducibility six times better than manual analysis for dose 20 uGy, the ability to reduce MMD until 10 uGy rather than 60 uGy with manual analysis or 20 uGy with peak 5 area method. In linearity, the sum of peak 3,4 and 5 method yields exactly linear dose response curve over the entire dose range

  6. The effect of the build-up wall at the TLD calibration using Co-60

    International Nuclear Information System (INIS)

    Nariyama, N.

    2000-01-01

    Absorbed dose in thermoluminescent dosimeter (TLD) material at the calibration using Co-60 gamma rays depends on the TLD thickness and the wall material used for electric equilibrium condition. The relation was examined for LiF, BeO and CaF 2 TLDs sandwiched with PMMA, Teflon and Pyrex glass walls using a Monte Carlo transport code and compared with cavity ionization theory calculations. For the mismatched combination of LiF, BeO/Pyrex glass and CaF 2 /PMMA, it was found that the energy deposition did not change monotonously with TLD thickness from small cavity to large cavity value: a depression observed around 1-mm thickness for LiF/Pyrex glass and a peak around 0.6-mm thickness for CaF 2 /PMMA. The phenomena were explained by using different exponential attenuation coefficients β and β' for the weighting functions of cavity theory. Moreover, use of large cavity values was found to lead possibly to 3-5% errors in the calibration of thin TLDs. (author)

  7. The study of new calibration features in the Harshaw TLD system

    International Nuclear Information System (INIS)

    Luo, L.Z.

    2005-01-01

    Full text: In the Harshaw TLD system, there are three key calibration procedures; the reader, the dosimeter and the algorithm. These procedures must be properly calibrated for the system to achieve the optimum results. For the conventional reader and dosimeter calibration, Harshaw recommends a pre-fade and a post-fade of 24 - 48 hours when calibrating the system. Harshaw also emphasizes that keeping the fade time consistent is important to maintain the quality of the system performance. In recent years, new calibration features have been introduced into the operating system. These new features are auto calibration, auto QC and auto blank, and they give the user the ability to set up the clear-expose-read performed automatically in a sequence for each dosimeter. This saves processing time and keeps the fade time the same. However, since the fade time is near zero, will it affect the TLD system calibration factors? What should the user expect? This paper presents a study of the effect of auto calibration / auto QC to the TLD operation. (author)

  8. Alanine and TLD coupled detectors for fast neutron dose measurements in neutron capture therapy (NCT)

    Energy Technology Data Exchange (ETDEWEB)

    Cecilia, A.; Baccaro, S.; Cemmi, A. [ENEA-FIS-ION, Casaccia RC, Via Anguillarese 301, 00060 Santa Maria di Galeria, Rome (Italy); Colli, V.; Gambarini, G. [Dept. of Physics of the Univ., INFN, Via Celoria 16, 20133 Milan (Italy); Rosi, G. [ENEA-FIS-ION, Casaccia RC, Via Anguillarese 301, 00060 Santa Maria di Galeria, Rome (Italy); Scolari, L. [Dept. of Physics of the Univ., INFN, Via Celoria 16, 20133 Milan (Italy)

    2004-07-01

    A method was investigated to measure gamma and fast neutron doses in phantoms exposed to an epithermal neutron beam designed for neutron capture therapy (NCT). The gamma dose component was measured by TLD-300 [CaF{sub 2}:Tm] and the fast neutron dose, mainly due to elastic scattering with hydrogen nuclei, was measured by alanine dosemeters [CH{sub 3}CH(NH{sub 2})COOH]. The gamma and fast neutron doses deposited in alanine dosemeters are very near to those released in tissue, because of the alanine tissue equivalence. Couples of TLD-300 and alanine dosemeters were irradiated in phantoms positioned in the epithermal column of the Tapiro reactor (ENEA-Casaccia RC). The dosemeter response depends on the linear energy transfer (LET) of radiation, hence the precision and reliability of the fast neutron dose values obtained with the proposed method have been investigated. Results showed that the combination of alanine and TLD detectors is a promising method to separate gamma dose and fast neutron dose in NCT. (authors)

  9. Evaluation of mixed energy neutron doses using TLD NG-67 type

    International Nuclear Information System (INIS)

    Akhadi, Mukhlis; Thoyib Thamrin, M; Usmiyati Dewi, K.

    2000-01-01

    A research has been carried out to develop dose evaluation method of mixed neutron source with its neutron doses can be classified to two groups, I.e neutron doses with energy ≥ 0.5 eV and thermal neutron doses with energy less than 0.5 e V consist of epithermal and fast neutron, but in this research they were classified as fast neutron. Development of this dose evaluation method was carried out by sensitivity (S) intercomparison of TLD-600 to fast neutron, mixed energy neutron of nuclear rectors, and thermal neutron. From the experiment it was obtained that the value of Sfast : Sreactor : Sthermal = 0.005 : 0.010 : 1. Calibration factor (CF) of TLD is defined as 1/S. from the sensitivity data it can be obtained that the value of Cffast : Cfreactor : Cfthermal = 200 :100 : 1. The value of Cfreactor can be applied for mixed energy neutron doses evaluation of TLD-600. Key word : dosemeter, neutron dose, calibration factor, fast neutron, thermal neutron, nuclear reactor

  10. A study on dose attenuation in bone density when TBI using diode detector and TLD

    International Nuclear Information System (INIS)

    Im, Hyun Sil; Lee, Jung Jin; Jang, Ahn Ki; KIm, Wan Sun

    2003-01-01

    Uniform dose distribution of the whole body is essential factor for the total body irradiation(TBI). In order to achieved this goal, we used to compensation filter to compensate body contour irregularity and thickness differences. But we can not compensate components of body, namely lung or bone. The purpose of this study is evaluation of dose attenuation in bone tissue when TBI using diode detectors and TLD system. The object of this study were 5 patients who undergo TBI at our hospital. Dosimetry system were diode detectors and TLD system. Treatment method was bilateral and delivered 10 MV X-ray from linear accelerator. Measurement points were head, neck, pelvis, knees and ankles. TLD used two patients and diode detectors used three patients. Results are as followed. All measured dose value were normalized skin dose. TLD dosimetry : Measured skin dose of head, neck, pelvis, knees and ankles were 92.78±3.3, 104.34±2.3, 98.03±1.4, 99.9±2.53, 98.17±0.56 respectably. Measured mid-depth dose of pelvis, knees and ankles were 86±1.82, 93.24±2.53, 91.50±2.84 respectably. There were 6.67%-11.65% dose attenuation at mid-depth in pelvis, knees and ankles. Diode detector : Measured skin dose of head, neck, pelvis, knees and ankles were 95.23±1.18, 98.33±0.6, 93.5±1.5, 87.3±1.5, 86.90±1.16 respectably. There were 4.53%-12.6% dose attenuation at mid-depth in pelvis, knees and ankles. We concluded that dose measurement with TLD or diode detector was inevitable when TBI treatment. Considered dose attenuation in bone tissue, We must have adequately deduction of compensator thickness that body portion involved bone tissue.

  11. Recommendations: Introducing the quality system into the use of significant ionizing radiation sources in radiotherapy. TLD audit by mail within the quality system in radiotherapy

    International Nuclear Information System (INIS)

    Ekendahl, D.; Valenta, J.; Horakova, I.

    2005-01-01

    The publication consists of the following sections: TLD measurement methodology (Description of the TLD system; Dose determination); TLD audit in radiotherapy: methodologies and evaluation of results (Checking the dose calculated by the planning system and beam quality control; Checking the calculated dose distribution using a versatile phantom; Checking the calculated doses for linear accelerators with multilammelar collimators; Evaluation and analysis of results; Organizing a performing audits by mail); and Annexes: Detailed guidelines and protocols for radiotherapy departments. (P.A.)

  12. Composite depth dose measurement for total skin electron (TSE) treatments using radiochromic film

    International Nuclear Information System (INIS)

    Gamble, Lisa M; Farrell, Thomas J; Jones, Glenn W; Hayward, Joseph E

    2003-01-01

    Total skin electron (TSE) radiotherapy is routinely used to treat cutaneous T-cell lymphomas and can be implemented using a modified Stanford technique. In our centre, the composite depth dose for this technique is achieved by a combination of two patient positions per day over a three-day cycle, and two gantry angles per patient position. Due to patient morphology, underdosed regions typically occur and have historically been measured using multiple thermoluminescent dosimeters (TLDs). We show that radiochromic film can be used as a two-dimensional relative dosimeter to measure the percent depth dose in TSE radiotherapy. Composite depth dose curves were measured in a cylindrical, polystyrene phantom and compared with TLD data. Both multiple films (1 film per day) and a single film were used in order to reproduce a realistic clinical scenario. First, three individual films were used to measure the depth dose, one per treatment day, and then compared with TLD data; this comparison showed a reasonable agreement. Secondly, a single film was used to measure the dose delivered over three daily treatments and then compared with TLD data; this comparison showed good agreement throughout the depth dose, which includes doses well below 1 Gy. It will be shown that one piece of radiochromic film is sufficient to measure the composite percent depth dose for a TSE beam, hence making radiochromic film a suitable candidate for monitoring underdosed patient regions

  13. Reasons for deviations outside the acceptance limits in the IAEA/WHO TLD audits for radiotherapy hospitals

    International Nuclear Information System (INIS)

    Vatnitsky, Stanislav; Izewska, Joanna

    2002-01-01

    The main purpose of the IAEA/WHO TLD postal dose audit programme for dosimetry in radiotherapy [1] is to provide an independent verification of the dose delivered by treatment machines in radiotherapy hospitals. The results of the TLD audit are considered acceptable if the relative deviation between the participant's stated dose and the TLD determined dose is within ±5%. The goal of this note is to draw the attention of participants of the TLD programme to some of the common reasons for deviations outside the acceptance limits. Armed with this knowledge, other participants may avoid similar problems in the future. The analysis of deviations presented here is based on the results of TLD audits of the calibration of approximately 1000 Co-60 beams and 600 high-energy X-ray beams performed in the period 1996-2001. A total of 259 deviations outside the ±5% limits have been detected, including 204 deviations for Co-60 beams (20% of all Co-60 beams checked) and 55 for high-energy X-ray beams (10% of all X-ray beams checked). It is worth mentioning that the percentage of large deviations (beyond 10%) is also higher for Co-60 beams than for highenergy X-ray beams. Some problems may be caused by obsolete dosimetry equipment or poor treatment machine conditions. Other problems may be due to insufficient training of staff working in radiotherapy. The clinical relevance of severe TLD deviations detected in the audit programme was confirmed in many cases, but, fortunately, not all-poor dosimetric results reflect deficiencies in the calibration of clinical beams or machine faults. Sometime it happens, that the TLDs are irradiated with an incorrect dose due to misunderstanding of the instructions on how to perform the TLD irradiation. Such dosimetry errors would have no direct impact on actual dose delivered to a patient

  14. Comparison of wrist and head TLD doses with whole body TLD doses during high active jobs at RAPS-5 and 6

    International Nuclear Information System (INIS)

    Sharma, Ravi Kant; Abhishek, Neel; Kakkar, Amandeep; Kumar, Rajesh

    2016-01-01

    In nuclear power plant radiation dose monitoring and assessment is done to control the individual dose and station collective doses. While performing a radioactive job on systems or equipment with significant radiation levels of non uniform and beaming radiation; there is potential of localized exposure to extremities hands in particular and lens of the eye in comparison to other body parts. Keeping in view of this, separate equivalent dose limit to the extremities (hands and feet) and lens of the eye are defined by ICRP. A study has been carried out during Biennial Shutdown (BSD) of RAPS-6 in the month of October-2015 to establish the correlation between the doses received by chest TLDs which is being used to estimate the effective whole body dose of the radiation worker and the doses received in wrist TLD and head TLDs which are being used to monitor the equivalent dose received by hands and lens of the eye with applying a suitable correction factor

  15. TLD postal dose quality audit service for Co-60 beams in reference conditions in Cuba

    International Nuclear Information System (INIS)

    Gutierrez Lores, S.; Walwyn Salas, G.; Alonso Villanueva, G.

    2008-01-01

    This report presents the methodology and experience of the Cuban's Secondary Standard Dosimetry Laboratory for the implementation of postal dose quality audits service for Co-60 beams in reference conditions, using TLDs. Under coordinated research project (Contract 10794) were bought (TLD -100) Tl rods type JR 1152F made in China, with dimensions of 6 mm x 1 mm x 1 mm. All of these rods were identified individually with a consecutive number made over one of its sides, using a fine tip of graphite. The method used to determinate the individual sensibility of the TL detectors was: irradiating a group of them, with the same history of irradiation and readout (100 rods approximately), four serial times in the same geometrical conditions, to read them out and to attribute to each of them a sensitivity factor. This sensitivity factor is equal to average for the 4 cycle of irradiation and readout of the quote between the TL readout from dosimeter i and the mean of all values for each cycle. The TLD signal was read using HARSHAW 2000C/B reader. The results obtained in the external verification of the accuracy of the dose determination by the TLD system were performed in cooperation with IAEA Dosimetry Laboratory at Seibersdorf in different years are shown, the results obtained of the quality audits carried out to the different services of radiotherapy of the country are analysed also. The quality audits are an useful tool for the improvement of the accuracy in the dosimetry of clinical beams of radiotherapy with Co-60, contributing this way to the improvement of the life quality to cancer patients of the Cuban system of health. (author)

  16. SU-E-T-87: Comparison Study of Dose Reconstruction From Cylindrical Diode Array Measurements, with TLD Measurements and Treatment Planning System Calculations in Anthropomorphic Head and Neck and Lung Phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Benhabib, S; Cardan, R; Huang, M; Brezovich, I; Popple, R [University of Alabama at Birmingham, Birmingham, AL (United States); Faught, A; Followill, D [UT MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-01

    Purpose: To assess dose calculated by the 3DVH software (Sun Nuclear Systems, Melbourne, FL) against TLD measurements and treatment planning system calculations in anthropomorphic phantoms. Methods: The IROC Houston (RPC) head and neck (HN) and lung phantoms were scanned and plans were generated using Eclipse (Varian Medical Systems, Milpitas, CA) following IROC Houston procedures. For the H and N phantom, 6 MV VMAT and 9-field dynamic MLC (DMLC) plans were created. For the lung phantom 6 MV VMAT and 15 MV 9-field dynamic MLC (DMLC) plans were created. The plans were delivered to the phantoms and to an ArcCHECK (Sun Nuclear Systems, Melbourne, FL). The head and neck phantom contained 8 TLDs located at PTV1 (4), PTV2 (2), and OAR Cord (2). The lung phantom contained 4 TLDs, 2 in the PTV, 1 in the cord, and 1 in the heart. Daily outputs were recorded before each measurement for correction. 3DVH dose reconstruction software was used to project the calculated dose to patient anatomy. Results: For the HN phantom, the maximum difference between 3DVH and TLDs was -3.4% and between 3DVH and Eclipse was 1.2%. For the lung plan the maximum difference between 3DVH and TLDs was 4.3%, except for the spinal cord for which 3DVH overestimated the TLD dose by 12%. The maximum difference between 3DVH and Eclipse was 0.3%. 3DVH agreed well with Eclipse because the dose reconstruction algorithm uses the diode measurements to perturb the dose calculated by the treatment planning system; therefore, if there is a problem in the modeling or heterogeneity correction, it will be carried through to 3DVH. Conclusion: 3DVH agreed well with Eclipse and TLD measurements. Comparison of 3DVH with film measurements is ongoing. Work supported by PHS grant CA10953 and CA81647 (NCI, DHHS)

  17. A quality control program for the thermoluminescence dosimeter (TLD) in personnel radiation monitoring

    International Nuclear Information System (INIS)

    Seo, Kyung Won; Kim, Jang Lyul; Lee, Sang Yoon; Lee, Hyung Sub

    1994-01-01

    High quality radiation dosimetry is essential for workers who rely upon personal dosemeters to record the amount of radiation to which they are exposed. The ministry of science and technology (MOST) issued a ministerial ordinance (No 199-15) about the technical criteria on personnel dosimeter processors on 1992. The purpose of this quality control program is to prescribe the procedures approved by the management of KAERI for implementing a quality badge service by means of TLD for personnel working in an area where they may be exposed to ionization radiation. (Author) 10 refs

  18. Thermoluminescent relative efficiencies of TLD-100 for nitrogen ions respect of gamma radiation

    International Nuclear Information System (INIS)

    Concha S, K.; Avila, O.; Gamboa de Buen, I.; Rodriguez V, M.; Buenfil, A.E.; Ruiz T, C.; Brandan, M.E.

    2004-01-01

    The purpose of this work is to measure the thermoluminescent relative efficiency of those TLD-100 dosemeters irradiated with nitrogen ions with respect to the gamma radiation of 60 Co, in function of the linear energy transfer (LET). Two energy of such nitrogen ions were selected that has the same value from LET when impacting in the dosemeters but with E 1 energy (4.8 MeV) and E 2 (9.95 MeV) smaller and greater respectively that the energy of the Bragg peak. (Author)

  19. Evaluation of the breast plan using the TLD and MOSFET for the skin dose

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seon Myeong; Kim, Young Bum; Bak, Sang Yun; Lee, Sang Rok; Jeong, Se Young [Dept. of Radiation Oncology, Korea University Ansan Hospital, Ansan (Korea, Republic of)

    2015-12-15

    The measurement of skin dose is very important that treatment of breast cancer. On account of the cold or hot dose as compared with prescription dose, it is necessary to analyse the skin dose occurring during the various plan of the breast cancer treatment. At our hospital, we want to apply various analyses using a diversity of dosimeters to the breast cancer treatment. In the study, the anthropomorphic phantom is used to find out the dose difference of the skin(draining site), scar and others occurring from the tangential treatment plan of breast cancer. We took computed tomography scan of the anthropomorphic phantom and made plans for the treatment planing using open and wedge, Field-in-Field, Dose fluence. Using these, we made a comparative analysis of the dose date points by using the Eclipse. For the dose comparison, we place the anthropomorphic phantom in the treatment room and compared the measurement results by using the TLD and MOSFET on the dose data points. On the central point of treatment planing basis, the upward and downward skin dose measured by the MOSFET was the highest when the fluence was used. The skin dose of inner and outer was distinguished from the figure(5.7% - 10.3%) when the measurements were fulfilled by using TLD and MOSFET. The other side of breast dose was the lowest in the open beam, on the other hand, is highest in the Dose fluence plan. In the different kinds of treatment, the dose deviation of inner and outer was the highest, and so this was the same with the TLD and MOSFET measurement case. The outer deviation was highest in the TLD, and the Inner' was highest in the MOSFET. Skin dose in relation to the treatment plan was the highest in the planing using the fluence technique in general and it was supposed that the high dose had been caused by the movement of the MLC. There's some differences among the all the treatment planning, but the sites such as IM node occurring the lack of dose, scar, drain site are needed pay

  20. Development and evaluation of new semi-automatic TLD reader software

    International Nuclear Information System (INIS)

    Pathan, M.S.; Pradhan, S.M.; Palani Selvam, T.; Datta, D.

    2018-01-01

    Nowadays, all technology advancement is primarily focused on creating the user-friendly environment while operating any machine, also minimizing the human errors by automation of procedures. In the present study development and evaluation of new software for semi-automatic TLD badge reader (TLDBR-7B) is presented. The software provides an interactive interface and is compatible with latest windows OS as well as USB mode of data communication. Important new features of the software are automatic glow curve analysis for identifying any abnormality, event log register, user defined limits on TL count and time of temperature stabilization for readout interruption and auto reading resumption options

  1. Evaluation of the breast plan using the TLD and MOSFET for the skin dose

    International Nuclear Information System (INIS)

    Kim, Seon Myeong; Kim, Young Bum; Bak, Sang Yun; Lee, Sang Rok; Jeong, Se Young

    2015-01-01

    The measurement of skin dose is very important that treatment of breast cancer. On account of the cold or hot dose as compared with prescription dose, it is necessary to analyse the skin dose occurring during the various plan of the breast cancer treatment. At our hospital, we want to apply various analyses using a diversity of dosimeters to the breast cancer treatment. In the study, the anthropomorphic phantom is used to find out the dose difference of the skin(draining site), scar and others occurring from the tangential treatment plan of breast cancer. We took computed tomography scan of the anthropomorphic phantom and made plans for the treatment planing using open and wedge, Field-in-Field, Dose fluence. Using these, we made a comparative analysis of the dose date points by using the Eclipse. For the dose comparison, we place the anthropomorphic phantom in the treatment room and compared the measurement results by using the TLD and MOSFET on the dose data points. On the central point of treatment planing basis, the upward and downward skin dose measured by the MOSFET was the highest when the fluence was used. The skin dose of inner and outer was distinguished from the figure(5.7% - 10.3%) when the measurements were fulfilled by using TLD and MOSFET. The other side of breast dose was the lowest in the open beam, on the other hand, is highest in the Dose fluence plan. In the different kinds of treatment, the dose deviation of inner and outer was the highest, and so this was the same with the TLD and MOSFET measurement case. The outer deviation was highest in the TLD, and the Inner' was highest in the MOSFET. Skin dose in relation to the treatment plan was the highest in the planing using the fluence technique in general and it was supposed that the high dose had been caused by the movement of the MLC. There's some differences among the all the treatment planning, but the sites such as IM node occurring the lack of dose, scar, drain site are needed pay

  2. TLD Postal service for quality audits of beams of Co-60 in reference conditions in Cuba

    International Nuclear Information System (INIS)

    Gutierrez L, S.; Walwyn S, G.; Alonso V, G.

    2006-01-01

    Purpose: To describe the methodology and experience of the Secondary Laboratory of Dosimetric Calibration of Cuba in the establishment of the TLD Postal Service for quality audits of beams of Co-60 in reference conditions. Materials and methods: Through the Coordinated Project of Research (Contract 10794) its was bought 200 solid thermoluminescent detectors of LiF: Mg, Ti (TLD-100) in micro bars form with dimensions of 6 x 1 x 1 mm and of the JR 1152F type manufactured in China. All these detectors were identified individually with a serial number on one of its faces, using a graphite fine sheet. Those detectors for its irradiation are introduced in cylindrical plastic capsules developed and used by the International Atomic Energy Agency (IAEA) in the Audit Postal Service of Dose IAEA/WHO, the capsules have one cavity equal to 3 mm for that is necessary to recover this cavity with a fine plastic tube so that the detectors remain immobile during the irradiation. The method used to determine the individual sensitivity of the thermoluminescent detectors is: to irradiate a detectors group (100 micro bars) 4 times in those same geometric conditions, with the same irradiation history and reading, then it is determine for each detector a sensitivity factor equal to the average of those readings obtained for the 4 irradiation cycles for each i detector among the average of all the reading values obtained during the 4 cycles. The thermoluminescent signal is obtained with a Harshaw 2000C/B reader manual. Results: The satisfactory results obtained in the verification of the calibration of the TLD system, using the reference irradiation service of the Seibersdorf Dosimetry Laboratory of the IAEA in three different years are shown. The results of the audits carried out to the different radiotherapy services of the country in different years are also presented. Conclusions: The experience with the detectors acquired in the project demonstrates that with an appropriate

  3. Interpretation of TLD data measured in the vicinity of nuclear power plants

    International Nuclear Information System (INIS)

    Czarnecki, J.; Baggenstos, M.; Schuler, J.; Voelkle, H.

    1981-01-01

    It is shown that incorporating the location-specific characteristics of natural radiation into the interpretation of the surrounding measurements makes some valuable contributions to the improvement of the measuring quality of thermoluminescent enviromental dosimetry. This brings the possibility to determine the net dose of the additional man-made radiations (e.g. caused by the nuclear power plant) with better accuracy. The authors propose a method of analysing the measured results which enables one to include the measured data from the evidence finding phase in the interpretation of the environment monitoring-TLD-measurement (orig./DG) [de

  4. Analysis of read-out heating rate effects on the glow peaks of TLD-100 using WinGCF software

    Energy Technology Data Exchange (ETDEWEB)

    Bauk, Sabar, E-mail: sabar@usm.my [Physics Section, School of Distance Education, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Hussin, Siti Fatimah [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Alam, Md. Shah [Physics Section, School of Distance Education, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Physics Department, Shahjalal University of Science and Technology, Sylhet (Bangladesh)

    2016-01-22

    This study was done to analyze the effects of the read-out heating rate on the LiF:Mg,Ti (TLD-100) thermoluminescent dosimeters (TLD) glow peaks using WinGCF computer software. The TLDs were exposed to X-ray photons with a potential difference of 72 kVp and 200 mAs in air and were read-out using a Harshaw 3500 TLD reader. The TLDs were read-out using four read-out heating rates at 10, 7, 4 and 1 °C s{sup −1}. It was observed that lowering the heating rate could separate more glow peaks. The activation energy for peak 5 was found to be lower than that for peak 4. The peak maximum temperature and the integral value of the main peak decreased as the heating rate decreases.

  5. Unusual ratio of TL readouts of different discs of personnel monitoring TLD badge based on CaSO4: Dy teflon disc

    International Nuclear Information System (INIS)

    Pradhan, S.M.; Ande, C.D.; Kher, R.K.; Chourasiya, G.; Vashishtha, R.; Gupta, A.K.

    2005-01-01

    In India Personnel Monitoring against external radiation hazard of gamma, beta and X-rays is provided using a TLD badge based on CaSO 4 : Dy Teflon TLD disc. Unusual ratios of TL readouts of different discs of TLD badge (Disc Ratios) observed for service TLD badges of radiation workers were investigated and simulated. Simulations were carried out by exposure of TLD badges by speck type radioactive sources placed in contact of badges, exposure of TLD badges placed on concrete floor to a radiography source. Clues for the simulation were obtained from nature of work, radiological conditions during course of individuals' work whose TLD badges showed the unusual disc ratios and geometrical calculations performed. It is concluded that although the actual exposure condition during use is unknown, the unusual disk ratios observed for the service TLD badges can be simulated and utilized to arrive at probable exposure conditions. The study helped in investigations of the abnormal exposures and assigning doses to the concerned radiation workers. (author)

  6. Development of a TLD mailed system for remote dosimetry audit for 192Ir HDR and PDR sources

    International Nuclear Information System (INIS)

    Roue, Amelie; Venselaar, Jack L.M.; Ferreira, Ivaldo H.; Bridier, Andre; Dam, Jan van

    2007-01-01

    Background and purpose: In the framework of an ESTRO ESQUIRE project, the BRAPHYQS Physics Network and the EQUAL-ESTRO laboratory have developed a procedure for checking the absorbed dose to water in the vicinity of HDR or PDR sources using a mailed TLD system. The methodology and the materials used in the procedure are based on the existing EQUAL-ESTRO external radiotherapy dose checks. Materials and methods: A phantom for TLD postal dose assurance service, adapted to accept catheters from different HDR afterloaders, has been developed. The phantom consists of three PMMA tubes supporting catheters placed at 120 degrees around a central TLD holder. A study on the use of LiF powder type DTL 937 (Philitech) has been performed in order to establish the TLD calibration in dose-to-water at a given distance from 192 Ir source, as well as to determine all correction factors to convert the TLD reading into absorbed dose to water. The dosimetric audit is based on the comparison between the dose to water measured with the TL dosimeter and the dose calculated by the clinical TPS. Results of the audits are classified in four different levels depending on the ratio of the measured dose to the stated dose. The total uncertainty budget in the measurement of the absorbed dose to water using TLD near an 192 Ir HDR source, including TLD reading, correction factors and TLD calibration coefficient, is determined as 3.27% (1 s). Results: To validate the procedures, the external audit was first tested among the members of the BRAPHYQS Network. Since November 2004, the test has been made available for use by all European brachytherapy centres. To date, 11 centres have participated in the checks and the results obtained are very encouraging. Nevertheless, one error detected has shown the usefulness of this audit. Conclusion: A method of absorbed dose to water determination in the vicinity of an 192 Ir brachytherapy source was developed for the purpose of a mailed TL dosimetry system. The

  7. External assurance program in radiotherapy dose by TLD: implementation of a quality system and extension to complex treatments

    International Nuclear Information System (INIS)

    Mojsiejczuk, N.; Lohr, J.; Molina, L.; Vallejos, M.; Montaño, G.; Stefanic, A.; Zaretzky, A.

    2011-01-01

    Until now, the Regional Reference Center with secondary patterns for dosimetry ('Centro Regional de Referencia con Patrones Secundarios para Dosimetria' (CRRD)) has done dosimetry verifications with thermoluminescent dosimeters (TLD) in radiotherapy in square and rectangular fields. The objective of this paper is to inform about the first tests done to span new verification conditions in irradiations with multi-leaf collimator using regular and irregular field shapes. On the other hand, it will briefly describe the progress in the implementation of a quality management system adopted by the CRRD, regarding the TLD verification service. (author)

  8. Development of a TLD mailed system for remote dosimetry audit for (192)Ir HDR and PDR sources.

    Science.gov (United States)

    Roué, Amélie; Venselaar, Jack L M; Ferreira, Ivaldo H; Bridier, André; Van Dam, Jan

    2007-04-01

    In the framework of an ESTRO ESQUIRE project, the BRAPHYQS Physics Network and the EQUAL-ESTRO laboratory have developed a procedure for checking the absorbed dose to water in the vicinity of HDR or PDR sources using a mailed TLD system. The methodology and the materials used in the procedure are based on the existing EQUAL-ESTRO external radiotherapy dose checks. A phantom for TLD postal dose assurance service, adapted to accept catheters from different HDR afterloaders, has been developed. The phantom consists of three PMMA tubes supporting catheters placed at 120 degrees around a central TLD holder. A study on the use of LiF powder type DTL 937 (Philitech) has been performed in order to establish the TLD calibration in dose-to-water at a given distance from (192)Ir source, as well as to determine all correction factors to convert the TLD reading into absorbed dose to water. The dosimetric audit is based on the comparison between the dose to water measured with the TL dosimeter and the dose calculated by the clinical TPS. Results of the audits are classified in four different levels depending on the ratio of the measured dose to the stated dose. The total uncertainty budget in the measurement of the absorbed dose to water using TLD near an (192)Ir HDR source, including TLD reading, correction factors and TLD calibration coefficient, is determined as 3.27% (1s). To validate the procedures, the external audit was first tested among the members of the BRAPHYQS Network. Since November 2004, the test has been made available for use by all European brachytherapy centres. To date, 11 centres have participated in the checks and the results obtained are very encouraging. Nevertheless, one error detected has shown the usefulness of this audit. A method of absorbed dose to water determination in the vicinity of an (192)Ir brachytherapy source was developed for the purpose of a mailed TL dosimetry system. The accuracy of the procedure was determined. This method allows a

  9. Unfolding neutron spectra obtained from BS–TLD system using genetic algorithm

    International Nuclear Information System (INIS)

    Santos, J.A.L.; Silva, E.R.; Ferreira, T.A.E; Vilela, E.C.

    2012-01-01

    Due to the variability of neutron spectrum within the same environment, it is essential that the spectral distribution as a function of energy should be characterized. The precise information allows radiological quantities establishment related to that spectrum, but it is necessary that a spectrometric system covers a large interval of energy and an unfolding process is appropriate. This paper proposes use of a technique of Artificial Intelligence (AI) called genetic algorithm (GA), which uses bio-inspired mathematical models with the implementation of a specific matrix to unfolding data obtained from a combination of TLDs embedded in a BS system to characterize the neutron spectrum as a function of energy. The results obtained with this method were in accordance with reference spectra, thus enabling this technique to unfold neutron spectra with the BS–TLD system. - Highlights: ► The unfolding code used the artificial intelligence technique called genetic algorithms. ► A response matrix specific to the unfolding data obtained with the BS–TLD system is used by the AGLN. ► The observed results demonstrate the potential use of genetic algorithms in solving complex nuclear problems.

  10. Measurements of environmental background radiation levels by TLD in and around the Jahangirnagar University Campus

    International Nuclear Information System (INIS)

    Mollah, A.S.; Aleya Begum; Idris Miah, M.; Yunus, Afrozi

    1997-01-01

    The background radiation levels at 30 locations in and around the Jahangirnagar University Campus (JUC) were measured using a LiF(TLD-100) thermoluminescent dosimeter (TLD). In addition, dose rates at three pre-selected locations were measured on a monthly as well as quarterly basis for one year period (July 1993 - June 1994). The dose rate ranges from 1016 to 2167 μSv.y -1 (101.6 to 216.7 mrem.y -1 ) with a mean value of 1595 μSv.y -1 (159.5 mrem.y -1 ). These values are comparable with those of pre- and post-operational values for the reactor site. The estimated average annual effective dose equivalent to the inhabitants at the study areas was found to be 1276 μSv (127.6 mrem). Variation of background radiation level with meteorological parameters, namely, temperature, rainfall, relative humidity and pressure was also studied. The influence on the dose rate of the meteorological parameters was observed. (author)

  11. TLD personnel monitoring dose estimation- extending the upper limit of the dose range

    International Nuclear Information System (INIS)

    Popli, K.L.; Sathian, Deepa; Divakaran, T.; Massand, O.P.

    2001-01-01

    TLD personnel monitoring was introduced in the year 1975 in India and at present nearly 41,000 radiation workers are being monitored by 13 monitoring laboratories all over India. The BARC- TLD being used for personnel monitoring is based on CaSO 4 :Dy embedded in PTFE and semi-automatic TL reader using hot N 2 Gas for heating the dosimeters. This reader has the range to measure γ dose from ten μSv to 3 μSv and x-ray dose form 1 μ Sv to 0.3 Sv due to the higher sensitivity of CaSO 4 : Dy to lower energy photons (20keV-50 keV) generated by diagnostic x-ray units. The x-ray radiation workers are at present nearly 35% of the total radiation workers monitored and this number is expected to grow as more and more number of x-ray workers are covered under this service. The upper limit of the x-ray dose range of the instrument is 0.3 Sv, whereas in the past one year it has been observed that at least 25% of the total overexposures reported in case of x-ray workers have recorded the dose more than 0.3 Sv. This paper presents the technique developed to extend the upper limit of the range from 0.3 Sv to 1 Sv for x-rays and 10 Sv for γ rays

  12. The design philosophy for an automatic TLD system to meet current international specifications

    International Nuclear Information System (INIS)

    Haaslahti, J.

    1986-01-01

    The object of this paper is to describe the elements of a new automatic TLD system intended to meet draft IEC/ISO proposals and ANSI requirements in the USA. Dosemeter badge design is based on ICRU recommendations. The basic intent has been to produce a standard system that can measure and file raw data that can be adapted to specific user requirements with software. The system consists of a programmable automatic reader, an automatic irradiator, a computer, and dosemeters for environmental, whole body, extremity, and clinical applications. The reader uses hot nitrogen heating and photon counting, and measurement conditions may be chosen with complete freedom. The reader can produce a real-time glow curve to assist in checking performance. The irradiator has a 90 Sr- 90 Y source to permit programmed irradiation for calibration and material sensitivity checks. Cassettes are used to hold TLD cards during processing. Cassette coding both identifies samples and calls measurement parameters into use from memory. The system can be preprogrammed to measure all common materials and all common dosemeter elements (both square and round). (author)

  13. On the determination of the post-irradiation time from the glow curve of TLD-100

    International Nuclear Information System (INIS)

    Weinstein, M.; German, U.; Dubinsky, S.; Alfassi, Z.B.

    2003-01-01

    The ratio of peak 3 to the sum of peaks 4 + 5 in TLD-100 was measured for various pre-irradiation and post-irradiation time periods, under conditions characteristic of routine personal dosimetry. It was confirmed that the value of this ratio depends only on the elapsed time between the prior readout and the present one, independent of the moment when the irradiation took place during the total time interval (storage time). This effect indicates that fading of peak 3 seems to be due mainly to changes in the unoccupied traps, and not to decay of trapped charges, being almost independent of the presence of electrons or holes in the traps. This observation leads to the conclusion that the suggestions in the past to use the decay of peak 3 in TLD-100 for the measurement of the elapsed time between irradiation and readout may have been wrong. On the other hand, the decay of peak 2 can be used to measure the elapsed time from irradiation, since the rate of decay is different when related to pre-irradiation and post-irradiation times, indicating a much higher decay rate of the trapped charges (Randall-Wilkins decay). However, because of the fast decay rate of peak 2, its use for determination of the elapsed time since irradiation is of little practical significance. (author)

  14. A Computerized QC Analysis of TLD Glow Curves for Personal Dosimetry Measurements Using TagQC Program

    International Nuclear Information System (INIS)

    Primo, S.; Datz, H.; Dar, A.

    2014-01-01

    The External Dosimetry Lab (EDL) at the Radiation Safety Division at Soreq Nuclear Research Center (SNRC) is ISO 17025 certified and provides its services to approximately 13,000 users throughout the country from various sectors such as medical, industrial and academic. About 95% of the users are monitored monthly for X-rays, and radiation using Thermoluminescence Dosimeter (TLD) cards that contain three LiF:Mg,Ti elements and the other users, who work also with thermal neutrons, use TLD cards that contain four LiF:Mg,Ti elements. All TLD cards are measured with the Thermo 8800pc reader.Suspicious TLD glow curve (GC) can cause wrong dose estimation so the EDL makes great efforts to ensure that each GC undergoes a careful QC procedure. The current QC procedure is performed manually and through a few steps using different softwares and databases in a long and complicated procedure: EDL staff needs to export all the results/GCs to be checked to an Excel file, followed by finding the suspicious GCs, which is done in a different program (WinREMS), According to the GC shapes (Figure 1 illustrates suitable and suspicious GC shapes) and the ratio between the elements result values, the inspecting technician corrects the data

  15. Response of TLD badge for the estimation of exposure conditions in diagnostic x-ray departments - use of lead aprons

    International Nuclear Information System (INIS)

    Pradhan, A.S.; Chatterjee, S.; Bakshi, A.K.

    2002-01-01

    The present study was undertaken to ascertain the conditions of exposure of the TLD badge and to evaluate the inaccuracy involved in the estimation of dose received by the worker using an averaged lead apron transmission factor for the use of the badge above lead apron

  16. Malaysia Participation in the IAEA/ WHO TLD Postal Dose Quality Audit Service: Data Analysis From 2011-2015

    International Nuclear Information System (INIS)

    Norhayati Abdullah; Taiman Kadni

    2016-01-01

    In this paper, we report the dosimetry methodology used and the results of 22 Malaysian radiotherapy centres participated in the Thermoluminescent Dosimeter (TLD) Postal Dose Quality Audit Service organised by the International Atomic Energy Agency (IAEA) in collaboration with World Health Organisation (WHO) from 2011 to 2015. In this audit, a set of three capsules of TLD (encapsulated with Lithium Flouride powder) including a control TLD were sent to the participating centres for irradiation with 2 Gy of absorbed dose to water under reference condition. In this period, a total of 70 photon beams consists of 43 beams and 27 beams produced by 6 MV and 10 MV photon beams, respectively have been audited. The results demonstrated that all participating centres comply with the acceptance limits of ±5 % as recommended by the International Commission on Radiation Units and Measurements (ICRU) Report 24, except eight photon beams from six centres. However, these centres presented better compliance results after followed up with a second round of TLD irradiation. (author)

  17. Application of combined TLD and CR-39 PNTD method for measurement of total dose and dose equivalent on ISS

    International Nuclear Information System (INIS)

    Benton, E.R.; Deme, S.; Apathy, I.

    2006-01-01

    To date, no single passive detector has been found that measures dose equivalent from ionizing radiation exposure in low-Earth orbit. We have developed the I.S.S. Passive Dosimetry System (P.D.S.), utilizing a combination of TLD in the form of the self-contained Pille TLD system and stacks of CR-39 plastic nuclear track detector (P.N.T.D.) oriented in three mutually orthogonal directions, to measure total dose and dose equivalent aboard the International Space Station (I.S.S.). The Pille TLD system, consisting on an on board reader and a large number of Ca 2 SO 4 :Dy TLD cells, is used to measure absorbed dose. The Pille TLD cells are read out and annealed by the I.S.S. crew on orbit, such that dose information for any time period or condition, e.g. for E.V.A. or following a solar particle event, is immediately available. Near-tissue equivalent CR-39 P.N.T.D. provides Let spectrum, dose, and dose equivalent from charged particles of LET ∞ H 2 O ≥ 10 keV/μm, including the secondaries produced in interactions with high-energy neutrons. Dose information from CR-39 P.N.T.D. is used to correct the absorbed dose component ≥ 10 keV/μm measured in TLD to obtain total dose. Dose equivalent from CR-39 P.N.T.D. is combined with the dose component <10 keV/μm measured in TLD to obtain total dose equivalent. Dose rates ranging from 165 to 250 μGy/day and dose equivalent rates ranging from 340 to 450 μSv/day were measured aboard I.S.S. during the Expedition 2 mission in 2001. Results from the P.D.S. are consistent with those from other passive detectors tested as part of the ground-based I.C.C.H.I.B.A.N. intercomparison of space radiation dosimeters. (authors)

  18. Implementation of a self-directed work team in a TLD Processing Center

    International Nuclear Information System (INIS)

    Arnwine, A.A.; Bogard, R.S.; Teasley, N.A.; Somers, D.E.; Souleyrette, M.L.

    1994-01-01

    In an effort to maintain productivity with a decreasing work force, the Oak Ridge Y-12 Plant has adopted the concept of Self-Directed Work Teams in various disciplines. The plant's Health Physics Department was able to eliminate a layer of front-line supervisors by establishing four self-directed work teams. Each team was able to choose their method of implementation. The TLD Processing Center Team chose to use project managment tools to ensure a smooth transition from the traditional work group to a self-directed approach. This process focused on establishing responsibilities, determining training requirements, determining a leadership style for the group, and performing a potential problem analysis for the transition. The transition also reviewed interface issues that could occur with upper management, matrix management, technical oversight, and organizational peers. The team's experience is also evaluated in comparison to other Self-Directed Work Teams

  19. Performance and Test Results of Harshaw Pelletised LiF:Mg,Ti TLD Material

    International Nuclear Information System (INIS)

    Velbeck, K.J.; Zhang, L.; Green, R.; Tomlins, P.

    1999-01-01

    BICRON NE has recently introduced a pelletised version of their popular TLD-100, 600 and 700 lithium fluoride based thermoluminescence dosemeters (TLDs). These materials can be used unmounted or in card and ring formats. Applications include whole-body, environmental, medical, and extremity monitoring. The former manufacturing process included purifying, growing doped LiF, grinding, blending, pressing, slicing, and dicing. The new process eliminates the last four steps, replacing them with a pelletising process. This process transforms the material directly from a powder to its final form. This new process provides the benefits of better batch uniformity and excellent dimensional consistency. The testing is described that was performed for the purpose of accepting the pelletised material as a directly interchangeable substitute for the same material produced by the former process. Tests performed include reproducibility, batch homogeneity, linearity, detection threshold, and light sensitivity. (author)

  20. A new TLD badge with machine readable ID for fully automated readout

    International Nuclear Information System (INIS)

    Kannan, S. Ratna P.; Kulkarni, M.S.

    2003-01-01

    The TLD badge currently being used for personnel monitoring of more than 40,000 radiation workers has a few drawbacks such as lack of on-badge machine readable ID code, delicate two-point clamping of dosimeters on an aluminium card with the chances of dosimeters falling off during handling or readout, projections on one side making automation of readout difficult etc. A new badge has been designed with a 8-digit identification code in the form of an array of holes and smooth exteriors to enable full automation of readout. The new badge also permits changing of dosimeters when necessary. The new design does not affect the readout time or the dosimetric characteristics. The salient features and the dosimetric characteristics are discussed. (author)

  1. Characterization of TLD-100 micro-cubes for use in small field dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Peña-Jiménez, Salvador, E-mail: zoid-9861@yahoo.com.mx; Gamboa-deBuen, Isabel, E-mail: gamboa@nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Av. Universidad 3000, 04510 DF (Mexico); Lárraga-Gutiérrez, José Manuel, E-mail: jose.larraga.gtz@gmail.com, E-mail: amanda.garcia.g@gmail.com; García-Garduño, Olivia Amanda, E-mail: jose.larraga.gtz@gmail.com, E-mail: amanda.garcia.g@gmail.com [Laboratorio de Física Médica, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Av. Insurgentes Sur 3877, 14269 DF (Mexico)

    2014-11-07

    At present there are no international regulations for the management of millimeter scale fields and there are no suggestions for a reference detector to perform the characterization and dose determination for unconventional radiation beams (small fields) so that the dosimetry of small fields remains an open research field worldwide because these fields are used in radiotherapy treatments. Sensitivity factors and reproducibility of TLD-100 micro-cubes (1×1×1 mm3) were determinate irradiating the dosimeters with a 6 MV beam in a linear accelerator dedicated to radiosurgery at the Instituto Nacional de Neurología y Neurocirugía (INNN). Thermoluminescent response as a function of dose was determined for doses in water between 0.5 and 3 Gy and two field sizes (2×2 cm2 and 10×10 cm2). It was found that the response is linear over the dose range studied and it does not depend on field size.

  2. Evaluation of the uncertainties in the TLD radiosurgery postal dose system

    Science.gov (United States)

    Campos, L. T.; Leite, S. P.; de Almeida, C. E. V.; Magalhães, L. A. G.

    2018-03-01

    Stereotactic radiosurgery is a single-fraction radiation therapy procedure for treating intracranial lesions using a stereotactic apparatus and multiple narrow beams delivered through noncoplanar isocentric arcs. To guarantee a high quality standard, a comprehensive Quality Assurance programme is extremely important to ensure that the measured dose is consistent with the tolerance considered to improve treatment quality. The Radiological Science Laboratory operates a postal audit programme in SRT and SRS. The purpose of the programme is to verify the target localization accuracy in known geometry and the dosimetric conditions of the TPS. The programme works in such a way those thermoluminescence dosimeters, consisting of LiF chips, are sent to the centre where they are to be irradiated to a certain dose. The TLD are then returned, where they are evaluated and the absorbed dose is obtained from TLDs readings. The aim of the present work is estimate the uncertainties in the process of dose determination, using experimental data.

  3. TLD environmental monitoring at the Institute of Nuclear Engineering in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Taam, I.H. [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Caixa Postal 68550, 21945-970 Rio de Janeiro, RJ (Brazil); Rosa, L.A.R. da [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Av. Salvador Allende s/n, Caixa Postal 37760, 22780-160 Rio de Janeiro, RJ (Brazil)], E-mail: lrosa@ird.gov.br; Crispim, V.R. [PEN/COPPE-DNC/POLI/CT/UFRJ, Caixa Postal 68509, 21941-972 Rio de Janeiro, RJ (Brazil)

    2008-09-15

    Since 2003 the Institute of Nuclear Engineering in Rio de Janeiro city, Brazil, operates a new cyclotron, RDS-111, to produce {sup 18}F-Fluorodeoxyglucose to be used in nuclear medicine. Additionally, the IEN radioactive waste repository has been enlarged during the past last years, receiving a considerable amount of radioactive materials. Therefore, it became necessary to evaluate a possible increase of the environmental gamma exposure rates at the institute site due to the operation of the new accelerator and the enlargement of the institute waste repository as well. LiF:Mg,Cu,P, TLD-100H, and TL detectors were employed for environmental kerma rate evaluation and the results were compared with previous results obtained before the RDS-111 operation initialisation and the enlargement of IEN waste repository. No significant contribution for the enhancement of environmental gamma kerma rates was detected.

  4. Nuclear accident dosimeter designed for use with the Panasonic TLD system

    International Nuclear Information System (INIS)

    Hankins, D.E.

    1985-01-01

    A new design for the nuclear accident dosimeter (NAD) compatible with the Panasonic TLD badge has recently been adopted for use at LLNL. This NAD was tested at the 1984 Oak Ridge National Laboratory Intercomparison of Criticality Accident Dosimeters study. We describe the procedures and constants developed to evaluate the NAD components. These constants were averaged to give reasonable results from bare and moderated spectra. Other procedures to evaluate a person's neutron dose using activation of the blood sodium and hair are described. These latter procedures are used to complement the dose determined using the NAD, or to determine a dose if a NAD had not been worn during exposure. If little is known about the configuration of the fissile material or shielding between the material and the exposed person, a procedure which combines the blood and hair activations gives a good estimate of the dose. (DT) 3 refs., 2 figs., 6 tabs

  5. Effect of temperatures up to 130 deg C on the responses of TLD 700

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, J A; Binns, P J [UKAEA Atomic Energy Research Establishment, Harwell. Environmental and Medical Sciences Div.

    1984-01-01

    The need to measure doses at temperatures up to 130 deg C led to an investigation into the effect of exposure and storage at these temperatures on the response of TLD 700 before and after UV phototransfer. As a preliminary, the delays required during the UV re-estimation process were optimised. The effects of storage and exposure were compared. This was followed by a detailed examination of the effects of storage at temperatures up to 130 deg C. Glow curves were analysed to investigate the rates of growth and decay of the different peaks. The findings for peaks 6 and 7 are compatible with previously reported effects at lower temperatures on peaks 3, 4 and 5. Storage at temperatures of 130 deg C or below for periods up to 28 days does not affect the UV photo-transfer response.

  6. Radiation doses measured by TLD (thermo luminescent dosimeter) in x-ray examination

    International Nuclear Information System (INIS)

    Yamamoto, Seiichi; Hiraki, Motoji; Murakami, Shozo; Nishikawa, Naozo; Yagi, Takayuki

    1977-01-01

    By means of TLD, we measured the radiation doses to the skin in the central area of the field of radiation and doses scattered outside of the radiation field, utilizing a phantom to define a suitable radiation field. Clinically, when radiography of the gall bladder and the chest was done, we measured both the radiation doses of the central skin area where radiation was done and the skin above the area of the female gonads. In radiography of the chest, the radiation doses to the skin area above the female gonads situate was under 0.1 mR. When female gonads are less than 15 cm from the margin of the radiation field of the radiation dose can be decreased by 30% if gum sheets containing lead are used to cover the skin area outside the radiation field. (auth.)

  7. A review of TLD's zero-count based on temperature and radiation history of them

    Science.gov (United States)

    Tunçel, Nina; Karakuş, İsmail; Dündar, Ertuğrul; Toykan Çiflikçi, Özlem

    2017-09-01

    In order to review the background value of a group of TLD-100, the zero-count values were collected from the first reading and after seven years after using them in experimental irradiations. The zero-counts for these two conditions were collected, as well as the dependence of temperature and radiation history of this group was evaluated. This study recommended that after frequently irradiation of TLDs the rearrangement for obtaining zero-count value must be performed before using TLDs in a new irradiation examination. Regarding on memory of radiation and thermal history, the sensitivity can change after receiving a large dose of radiation and undergoing readout. Additional annealing would be necessary to restore the original sensitivity. TLDs must be used under reproducible conditions to obtain consistent results.

  8. The cardiac catheterization laboratory personnel TLD dosimetry in Dr. Faghihi Hospital in Shiraz

    International Nuclear Information System (INIS)

    Derakhshan, Sh.

    2004-01-01

    In this study all of the personnel of Angiography of Dr.Faghihi hospital used TLD service During 2002-2003. This service was given by center for Radiation Protection and Application of the Shiraz University. These staff were divided in two group, one groups was technicians and the other group was the nurses. The result of this research shows that the maximum dose received to Technicians and nurses were 0.4mSv and 0.55mSV respectively. The average annual dose to technicians and nurses were 0.02 mSv and 0.19 mSv. This result shows that the nurses of this hospital receive more dose than the techniques

  9. Response of TLD-100 LiF dosimeters for X-rays of low energies

    International Nuclear Information System (INIS)

    Bonzi, E. V.; Mainardi, R. T.

    2011-10-01

    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)

  10. Thermoluminescence of pure LiF and Lif (TLD-100) irradiated at room temperature

    International Nuclear Information System (INIS)

    Sagastibelza Chivite, F.

    1980-01-01

    The thermoluminescence of pure LiF and LiF (TLD-100) crystals irradiated at room temperature with x - or gamma-rays has been studied up to 460 degree centigree. For most of the glow peaks found the kinetics, preexponential factors and activation energies have been determined. These parameters have been obtained by means of the isothermal method. The study of the thermal annealing of the radiation induced F and Z centres has allow to show that there is a correlation among the glow peaks and the annealing stages of these centres. It is concluded that the F and Z - centres play the role of recombination centres for halogen interstitial atom thermally released from traps. Light emission occurs in this recombination. (Author) 120 refs

  11. Evaluation of the kinetic parameters of CaF2:Tm (TLD-300) thermoluminescence dosemeters

    International Nuclear Information System (INIS)

    Azorin, Juan; Gutierrez, Alicia; Furetta, Claudio

    1989-01-01

    The kinetic parameters of the first, third and fifth peaks of CaF 2 :Tm (TLD-300) dosemeters were determined experimentally using methods based on initial rise, peak shape, different heating rates, isothermal decay and numerical fitting method and a comparison was made between the results obtained. The average activation energy values determined by the methods used here were 0.72, 1.16 and 1.77 eV, with mean values for the frequency factor of 2.58 x 10 8 , 2.89 x 10 13 and 6.16 x 10 16 s -1 for the first, third and fifth peaks respectively. The values of activation energy obtained for each peak using the different methods covered a spread of about 4%. However, the spread for each of the frequency factors was very high. (author)

  12. Unfolding neutron spectra with BS-TLD system using genetic algorithms

    International Nuclear Information System (INIS)

    Santos, Joelan A.L.; Silva, Everton R.; Vilela, Eudice C.

    2011-01-01

    Due to the variability of neutron spectrum within the same environment, it is essential that the spectral distribution as function of energy to be characterized. To perform this task, the neutron spectrometer has a primary role in determining the neutron flux (Φ E (E)). Precise information allows radiological quantities establishment related to that spectrum but it is necessary, however, a series of steps with a spectrometric system that can cover a large interval of energy and whose answer is isotropic. The most widely used for accomplishing this task is the spectrometric Bonner spheres system. One of the biggest problems related to neutron spectrometry is the process of data analysis, known as unfolding. Most of the work undertaken to implement new techniques of this process, using data obtained with the scintillator 6 LiI(I). However, characteristics related to the dead time make it not be so effective when used in high flow neutron fields. An alternative to this problem is the use of thermoluminescent detectors (TLD), but the codes used do not provide a more specific response matrix to unfolding the information obtained through these materials, which makes the development of a specific response matrix important to adequately characterize the response obtained by them. This paper proposes using a technique of artificial intelligence called genetic algorithm, which uses bio-inspired mathematical models and through the implementation of a specific matrix to unfolding data obtained from a combination of TLDs embedded in a system of Bonner spheres, such as thermal neutron detectors, to characterize the neutron spectrum as a function of energy. The results obtained with this method were in accordance with reference spectra, thus enables of this technique to unfolding neutrons spectra with BS-TLD system. (author)

  13. Unfolding neutron spectra with BS-TLD system using genetic algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Joelan A.L., E-mail: jasantos@cnen.gov.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Silva, Everton R. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Centro de Informatica; Ferreira, Tiago A.E. [Universidade Federal Rural de Pernambuco (UFRPE), Recife, PE (Brazil). Dept. de Estatistica e Informatica; Fonseca, Evaldo S. [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Vilela, Eudice C., E-mail: ecvilela@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2011-07-01

    Due to the variability of neutron spectrum within the same environment, it is essential that the spectral distribution as function of energy to be characterized. To perform this task, the neutron spectrometer has a primary role in determining the neutron flux ({Phi}{sub E}(E)). Precise information allows radiological quantities establishment related to that spectrum but it is necessary, however, a series of steps with a spectrometric system that can cover a large interval of energy and whose answer is isotropic. The most widely used for accomplishing this task is the spectrometric Bonner spheres system. One of the biggest problems related to neutron spectrometry is the process of data analysis, known as unfolding. Most of the work undertaken to implement new techniques of this process, using data obtained with the scintillator {sup 6}LiI(I). However, characteristics related to the dead time make it not be so effective when used in high flow neutron fields. An alternative to this problem is the use of thermoluminescent detectors (TLD), but the codes used do not provide a more specific response matrix to unfolding the information obtained through these materials, which makes the development of a specific response matrix important to adequately characterize the response obtained by them. This paper proposes using a technique of artificial intelligence called genetic algorithm, which uses bio-inspired mathematical models and through the implementation of a specific matrix to unfolding data obtained from a combination of TLDs embedded in a system of Bonner spheres, such as thermal neutron detectors, to characterize the neutron spectrum as a function of energy. The results obtained with this method were in accordance with reference spectra, thus enables of this technique to unfolding neutrons spectra with BS-TLD system. (author)

  14. A TLD-based personal dosemeter system for air crew monitoring

    International Nuclear Information System (INIS)

    Hajek, M.; Berger, T.; Vana, N.

    2003-01-01

    Full text: Due to the complex spectrum of different particles and energies involved, in-flight radiation dosimetry is usually associated with extensive instrumentation. The exposure of air crew personnel to cosmic radiation is paid serious attention, being further enhanced by the release of the European Council Directive 96/29/Euratom which makes the surveillance of crew members an obligatory issue. The high temperature ratio (HTR) method for small and easy-to-handle LiF:Mg,Ti thermoluminescent dosimeters was developed at the Atomic Institute of the Austrian Universities and fulfils these demands by permitting the determination of dose equivalent in radiation fields of unknown composition. The method uses the relative intensity of glow peaks 6 and 7 compared with the dominant peak 5 in the LiF Tl emission as an indication for the average LET and, thus, the mean quality factor of the radiation field. Extensive experiments in various ion beams established a HTR vs. LET calibration curve for the commercially available Tl phosphors TLD-600 and TLD-700. Additionally, the different neutron sensitivity of both types may be exploited for the determination of the dose equivalent delivered from neutrons which dominate at aviation altitudes. However, it is essential that the calibration of the Tl detectors is performed in a neutron environment of similar spectral shape as that encountered in flight. In our case, this constraint was satisfied by the CERN-EU High-Energy Reference Field (CERF). Results of both neutron and total dose equivalent for several different north-bound and trans-equatorial routes are presented, ranging from 2.1 ± 0.1 μSv/h with a 30 % neutron contribution for Vienna-Sydney to 4.9 ± 0.2 μSv/h and a roughly 55 % neutron contribution for Vienna-Tokyo. The measured route doses are compared with CARI-6M calculations. (author)

  15. Measuring thermo-luminescence efficiency of TLD-2000 detectors to different energy photons

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Wei Min; Chen, Bao Wei; Han, Yi; Yang, Zhong Jian [China Institute for Radiation Protection, Taiyuan (China)

    2016-06-15

    As an important detecting device, TLD is a widely used in the radiation monitoring. It is essential for us to study the property of detecting element. The aim of this study is to calculate the thermo-luminescence efficiency of TL elements. A batch of thermo-luminescence elements were irradiated by the filtered X-ray beams of average energies in the range 40-200 kVp, 662 keV {sup 137}Cs gamma rays and then the amounts of lights were measured by the TL reader. The deposition energies in elements were calculated by theory formula and Monte Carlo simulation. The unit absorbed dose in elements by photons with different energies corresponding to the amounts of lights was calculated, which is called the thermo luminescent efficiency (η(E)). Because of the amounts of lights can be calculated by the absorbed dose in elements multiply η(E), the η(E) can be calculated by the experimental data (the amounts of lights) divided by absorbed dose. The deviation of simulation results compared with theoretical calculation results were less than 5%, so the absorbed dose in elements was calculated by simulation results in here. The change range of η(E) value, relative to 662 keV {sup 137}Cs gamma rays, is about 30% in the energy range of 33 keV to 662 keV, is in accordance by the comparison with relevant foreign literatures. The η(E) values can be used for updating the amounts of lights that are got by the direct ratio assumed relations with deposition energy in TL elements, which can largely reduce the error of calculation results of the amounts of lights. These data can be used for the design of individual dosimeter which used TLD-2000 thermo-luminescence elements, also have a certain reference value for manufacturer to improve the energy-response performance of TL elements by formulation adjustment.

  16. QA Programme of the TLD laboratory of the University of Costa Rica: IEC 61066 testing

    International Nuclear Information System (INIS)

    Mora, Patricia; Porras Chaverria, Mariela

    2008-01-01

    The Thermoluminescence Personal Dosimetry Laboratory of the University of Costa Rica provides dose measurements for around 90% of occupational radiation workers in the country. The assessment of doses to workers routinely exposed to external sources of radiation constitutes an integral part of any radiation protection programme and helps national authorities to ensure acceptably safe and satisfactory radiological conditions in workplaces. Harshaw Readers Model 4000 and 4500, dosimeter holders Type 8814 with TLD-100 in 0110 cards and loose TLD-100 chips are used to monitor personal dose equivalent, Hp(10) and Hp(0.07). In order to provide a reliable measurement of the operational quantities, a study was undertaken to verify the fulfillment of international requirements in our system (Model 4500 with cards) against the Thermoluminescence dosimetry systems for personal and environmental monitoring CEI IEC 61066 (1991 -2012). The type tests performed were nine in total: batch homogeneity, reproducibility, linearity, detection threshold, effect of climate conditions on reader, effect of light exposure on dosimeters, isotropy, transient voltage and dropping on dosimeters. A Cesium-137 source was used to irradiate the dosimeters and all procedures follow the indications given on the standard. Results showed that all IEC criteria were met by our Laboratory. Acceptable uncertainties were also studied under the ICRP recommendations; the analysis of the Trumpet Curve was done with satisfactory results (for doses above 0.5 mSv; quotient of measure to real dose less than 3%). For purposes of accreditation (ISO/IEC 17025:2005) and performance testing this work is very relevant since the University of Costa Rica wants to establish a solid individual monitoring programme for external radiation exposure that will provide users, registrants, licensees and regulatory bodies with information that can be used for the optimization of protection and dose limitation of Costa Rican workers

  17. The IAEA/WHO TLD postal dose quality audits for radiotherapy: a perspective of dosimetry practices at hospitals in developing countries

    International Nuclear Information System (INIS)

    Izewska, Joanna; Andreo, Pedro; Vatnitsky, Stanislav; Shortt, Ken R.

    2003-01-01

    Background and purpose: The IAEA/WHO TLD postal programme for external audits of the calibration of high-energy photon beams used in radiotherapy has been in operation since 1969. This work presents a survey of the 1317 TLD audits carried out during 1998-2001. The TLD results are discussed from the perspective of the dosimetry practices in hospitals in developing countries, based on the information provided by the participants in their TLD data sheets. Materials and methods: A detailed analysis of the TLD data sheets is systematically performed at the IAEA. It helps to trace the source of any discrepancy between the TLD measured dose and the user stated dose, and also provides information on equipment, dosimetry procedures and the use of codes of practice in the countries participating in the IAEA/WHO TLD audits. Result: The TLD results are within the 5% acceptance limit for 84% of the participants. The results for accelerator beams are typically better than for Co-60 units. Approximately 75% of participants reported dosimetry data, including details on their procedure for dose determination from ionisation chamber measurements. For the remaining 25% of hospitals, who did not submit these data, the results are poorer than the global TLD results. Most hospitals have Farmer type ionisation chambers calibrated in terms of air kerma by a standards laboratory. Less than 10% of the hospitals use new codes of practice based on standards of absorbed dose to water. Conclusion: Despite the differences in dosimetry equipment, traceability to different standards laboratories and uncertainties arising from the use of various dosimetry codes of practice, the determination of absorbed dose to water for photon beams typically agrees within 2% among hospitals. Correct implementation of any of the dosimetry protocols should ensure that significant errors in dosimetry are avoided

  18. Personal dosimetry TLD 100 in orthopedic surgeons exposed to ionizing radiation in Bogota - Colombia; Dosimetria personal TLD 110 en medicos ortopedistas expuestos a radiacion ionizante en Bogota - Colombia

    Energy Technology Data Exchange (ETDEWEB)

    Sierra C, B. Y.; Jimenez, Y. [Universidad Nacional de Colombia, Departamento de Fisica, Grupo de Fisica Medica, Carrera 45 No. 26-85, Bogota (Colombia); Plazas, M. C. [Hospital Universitario Fundacion Santa Fe de Bogota, Instituto de Oncologia Carlos Ardila Lulle, Calle 119, No. 7-90, 220246 Bogota (Colombia); Eslava S, J. [Universidad Nacional de Colombia, Instituto de Investigaciones Clinicas, Grupo Equidad en Salud, Carrera 45 No. 26-85, Bogota (Colombia); Groot R, H., E-mail: brigith.sierra@gmail.com [Universidad de los Andes, Laboratorio de Genetica Humana, Carrera 1 No. 18A -12, Bogota (Colombia)

    2014-08-15

    Orthopedic surgeons should be considered as professionals occupationally exposed to ionizing radiation, for using C arc (fluoroscope) an equipment of X type radiation emission, during surgical procedures for imaging generation. Some health institutes, use of C arc under uncontrolled circumstances, such a lack of dosimetry control, incomplete or absence of personnel protective elements and protective measures, which in turn, lead to a high exposition to the personnel. Materials and methods. Study of double match cohort by age and gender, was conducted, in four health institutions of second and third level of attention in Bogota city. Personal dosimetry measurements with TLD-100 dosimetry crystals in both cohorts and environmental dosimetry in each of operation rooms used for orthopedic procedures, were carry out during six months of follow up. Dosimetry crystals were read in a Harshaw 4500 - Bicron equipment, in the Medical Physics Laboratory of National University of Colombia. Results. Dosimetry measurements are compatibles with those of occupationally exposed personnel 3.44 mSv/6 m CI 95% (1.66-3.99), even does not overpass ICRP recommendations, are higher as were expect at the beginning of the study. The median of effective accumulative dose in thorax is 3,4 mSv CI 95% (1,66-3,99), higher in comparison with neck value 2,7 mSv CI 95% (1,73-3,80) and hand dosimetry 1,42 mSv CI 95% (0,96-2,34). Conclusions: Orthopedic surgeons should be considered occupational exposed to ionizing radiation, who has to accomplish to the radiological protection measures, dosimetric follow up and maintenance of the used X ray equipment. It was confirm throughout this study that dosimetry shows higher levels as expected at the beginning of the study, compatible with occupationally exposed personnel. (Author)

  19. Traceability of a panoramic gamma irradiator using different TLD systems as transfer Instruments; Trazabilidad de un irradiador panoramico mediante sistemas de dosimetria TL

    Energy Technology Data Exchange (ETDEWEB)

    Romero, A. M.; Saez, J. C

    1994-07-01

    This work shows the calibration in terms of the new operational radiological quantities Hp (10) and H(10) for different TLD systems (Harshaw TLD-100 and Panasonic UD-002) used in personal and environmental monitoring. The irradiations were performed in the Spanish Reference Laboratory in radiation protection levels, managed by the CIEMAT Metrology of ionizing radiations Unit. With those data, different calibrations of a panoramic gamma irradiator in terms of the radiological quantity for unit of time were established, providing the traceability of the irradiator to the Reference Laboratory using the corresponding TLD systems as transfer instruments. (Author) 9 refs.

  20. Traceability of a panoramic gamma irradiator using different TLD systems as transfer instruments; Trazabilidad de un irradiador panoramico mediante sistemas de dosimetria TL

    Energy Technology Data Exchange (ETDEWEB)

    Romero, A.M.; Saez, J.C.

    1994-08-01

    This work shows the calibration in terms of the new operational radiological quantities Hp(10) and H*(10) for different TLD systems (Harshaw TLD-100 and Panasonic UD-802) used in personal and environmental monitoring. The irradiations were performed in the Spanish Reference Laboratory in radiation protection levels, managed by the CIEMAT Metrology of ionizing radiations Unit. With these data, different calibrations of a panoramic gamma irradiator in terms of the radiological quantity for unit of time were established, providing the traceability of the irradiator to the Reference Laboratory using the corresponding TLD systems as transfer instruments. (Author) 9 refs.

  1. Relative thermoluminescent efficiencies proton/gamma and helium/gamma of high temperature peaks in TLD-100 dosemeters; Eficiencias termoluminiscentes relativas proton/gamma y helio/gamma de picos de alta temperatura en dosimetros TLD-100

    Energy Technology Data Exchange (ETDEWEB)

    Flores M, E.; Avila, O.; Rodriguez V, M. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico); Massillon, J.L.G.; Buenfil A, E.; Ruiz T, C.; Brandan, M.E. [IFUNAM, 04500 Mexico D.F. (Mexico); Gamboa De Buen, I. [ICN-UNAM, 04500 Mexico D.F. (Mexico)

    2007-07-01

    This work presents measures of relative thermoluminescent efficiency of those high temperature peaks of TLD-100 dosemeters exposed to protons of 1.5 MeV and to helium nuclei of 3 and 7.5 MeV. A rigorous reading and of deconvolution protocol was used for the calculation of the TL efficiencies. Additionally an Excel program that facilitated the deconvolution adjustment process of the glow curves was elaborated. (Author)

  2. Comparison between indicators dosimetric released by teams and estimates by dosimetry TLD in the mammography of the Hospital Universitario 12 de Octubre

    International Nuclear Information System (INIS)

    Rot San Juan, M. J.; Martinez Gomez, L. C.; Gilarranz Moreno, R.; Milanes Gaillet, A. I.; Adaimi Hernandez, P.; Delgado rodriguez, J. M.

    2013-01-01

    With the incorporation of new technology, computers have indicators of dose for this magnitude. In this work we will compare to the mammography in our area the measure with the DSE TLD values thrown by the equipment. (Author)

  3. Performance evaluation of vertical feed fully automated TLD badge reader using 0.8 and 0.4 mm teflon embedded CaSO4:Dy dosimeters

    International Nuclear Information System (INIS)

    Ratna, P.; More, Vinay; Kulkarni, M.S.

    2012-01-01

    The personnel monitoring of more than 80,000 radiation workers in India is at present carried out by semi-automated TLD badge Reader systems (TLDBR-7B) developed by Radiation Safety Systems Division, Bhabha Atomic Research Centre. More than 60 such reader systems are in use in all the personnel monitoring centers in the country. Radiation Safety Systems Division also developed the fully automated TLD badge reader based on a new TLD badge having built-in machine readable ID code (in the form of 16x3 hole pattern). This automated reader is designed with minimum of changes in the electronics and mechanical hardware in the semiautomatic version (TLDBR-7B) so that such semi-automatic readers can be easily upgraded to the fully automated versions by using the new TLD badge with ID code. The reader was capable of reading 50 TLD cards in 90 minutes. Based on the feedback from the users, a new model of frilly automated TLD badge Reader (model VEFFA-10) is designed which is an improved version of the previously reported fully Automated TLD badge reader. This VEFFA-10 PC based Reader incorporates vertical loading of TLD bards having machine readable ID code. In this new reader, a vertical rack, which can hold 100 such cards, is mounted from the right side of the reader system. The TLD card falls into the channel by gravity from where it is taken to the reading position by rack and pinion method. After the readout, the TLD card is dropped in a eject tray. The reader employs hot N 2 gas heating method and the gas flow is controlled by a specially designed digital gas flow meter on the front panel of the reader system. The system design is very compact and simple and card stuck up problem is totally eliminated in the reader system. The reader has a number of self-diagnostic features to ensure a high degree of reliability. This paper reports the performance evaluation of the Reader using 0.4 mm thick Teflon embedded CaSO 4 :Dy TLD cards instead of 0.8 mm cards

  4. TLD-100 glow-curve deconvolution for the evaluation of the thermal stress and radiation damage effects

    CERN Document Server

    Sabini, M G; Cuttone, G; Guasti, A; Mazzocchi, S; Raffaele, L

    2002-01-01

    In this work, the dose response of TLD-100 dosimeters has been studied in a 62 MeV clinical proton beams. The signal versus dose curve has been compared with the one measured in a sup 6 sup 0 Co beam. Different experiments have been performed in order to observe the thermal stress and the radiation damage effects on the detector sensitivity. A LET dependence of the TL response has been observed. In order to get a physical interpretation of these effects, a computerised glow-curve deconvolution has been employed. The results of all the performed experiments and deconvolutions are extensively reported, and the TLD-100 possible fields of application in the clinical proton dosimetry are discussed.

  5. N2 gas station and gas distribution system for TLD personnel monitoring gas based semi-automatic badge readers

    International Nuclear Information System (INIS)

    Chourasiya, G.; Pradhan, S.M.; Kher, R.K.; Bhatt, B.C

    2003-01-01

    Full text: New improvised hot gas based Auto TLD badge reader has several advantages over the earlier contact heating based manual badge reader. It requires constant supply of N 2 gas for its operation; The gas supplied using replaceable individual gas cylinders may have some safety hazards in their handling. It was therefore considered worthwhile to setup a N 2 gas assembly/ station outside the lab area and to bring regulated gas supply through network of tubes with proper regulation to the individual readers. The paper presents detailed description of the gas station and distribution system. The system is quite useful and offers several practical advantages for readout of TLD badges on the semiautomatic badge readers based on gas heating. Important advantage from dosimetric point of view is avoidance of gas flow rate fluctuations and corresponding variations in TL readouts

  6. An approach to an analysis of the energy response of LiF-TLD to high energy electrons

    International Nuclear Information System (INIS)

    Shiragai, A.

    1977-01-01

    Responses of LiF-TLD to high energy electrons relative to 60 Co γ-rays were investigated experimentally and theoretically. The Burlin et al. theory (Burlin, T.E., Snelling, R.J., and Owen, B., 1969, in Proc.2nd Symp. on Microdosimetry, Stresa, Italy; Brussels: Commission of European Communities; p.455), its modified version by Almond and McCray (Almond, P.R., and McCray, K., 1970, Phys.Med.Biol., vol.15, 335 and 746) and the Holt et al. semi-empirical theory (Holt, J.G., Edelstein, G.R., and Clark, T.E., 1975, Phys.Med.Biol., vol.20, 559) were examined in comparison with each experiment. An approximate approach to theoretical analysis of energy response of LiF-TLD was attempted and compared with some experimental results. (author)

  7. Thermoluminescent response of dosemeters TLD-100 exposed to distinct baker protocols, irradiation and reading

    International Nuclear Information System (INIS)

    Estrada E, D.

    2002-01-01

    The interest that motivated the realization of this work is the opposing discrepancy among the values of the efficiency thermoluminescent of heavy charged particles (PCP) regarding gamma radiation (η PCP , γ) reported in different works and gathered recently for Horowitz (Ho 01). The measures of relative thermoluminescent efficiency have importance in relation to the dosimetry associated to medical therapy with heavy charged particle. The measurement of η PCP , γ depends of multiple experimental factors. To understand this dependence it was quantified the effect of using different procedures experimental in the estimate of the relative thermoluminescent efficiency of dosemeters TLD-100 (LiF: Ti; Mg) for protons of 3 MeV regarding gamma rays of 60 Co (η PCP , γ), varying the lot, the presentation, the one baked and the team reader. When was used the same global procedure values they were obtained for (η PCP , γ) inside the interval [0.30, 0.58] for the peak 5 and [0.35, 0.76] for the total thermoluminescent signal (Tl). At the use different equipment, baked and lot are obtained maximum differences of 30%, 12% and 6% respectively in the values of (η PCP , γ) for the peak 5, and 25%, 28% and 7% for the total Tl signal. The changes more significant of 36% and 44% for peak 5 and total signal respectively are obtained when changing the presentation of the dosemeter. As a complementary investigation it was studied the distribution of the Tl signal of each peak in the deconvolution of the curve of brightness with regard to the total signal in exposed dosemeters to high fluence of protons (1x10 10 p/cm 2 ) varying the experimental protocol. It was found that the distribution of the Tl signal has a difference of the order of 5% when changing the used reading team. It was observed that the contribution of the peak 5 regarding the total signal are preserved when changing baked and that it results to be 8% greater for the presentation in dosemeters of 1 x 1 x 1 mm 3

  8. Personnel photon dosimeter on the base of TLD sup n sup a sup t LiF

    CERN Document Server

    Kaskanov, G Y

    2003-01-01

    A personnel photon dosemeter on the basis of thermoluminescence detectors (TLD) sup n sup a sup t LiF is described. Experimental responses of the dosemeters in the unit of individual equivalent dose H sub p (10) for energy of photons 59.5, 120, 662, and 1250 keV are presented. It is shown that the dosemeter allows one to measure H sub p (10) with admissible uncertainty in the energy range from 60 to 1250 keV.

  9. Relative thermoluminescent efficiencies proton/gamma and helium/gamma of high temperature peaks in TLD-100 dosemeters

    International Nuclear Information System (INIS)

    Flores M, E.; Avila, O.; Rodriguez V, M.; Massillon, J.L.G.; Buenfil A, E.; Ruiz T, C.; Brandan, M.E.; Gamboa De Buen, I.

    2007-01-01

    This work presents measures of relative thermoluminescent efficiency of those high temperature peaks of TLD-100 dosemeters exposed to protons of 1.5 MeV and to helium nuclei of 3 and 7.5 MeV. A rigorous reading and of deconvolution protocol was used for the calculation of the TL efficiencies. Additionally an Excel program that facilitated the deconvolution adjustment process of the glow curves was elaborated. (Author)

  10. Study of the influence of the time temperature profile on the minimum detectable dose of TLD-100

    Energy Technology Data Exchange (ETDEWEB)

    Meireles, Leonardo S.; Lacerda, Marco Aurelio S.; Meira-Belo, Luiz C.; Ferreira, Hudson R., E-mail: meirelesls@cdtn.br, E-mail: masl@cdtn.br, E-mail: lcmb@cdtn.br, E-mail: hrf@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    Monitoring of workers and workplaces is an integral part of any radiation protection programme (RPP). It is essential to demonstrate compliance with regulations that limit the allowable dose to the public from manmade sources and to enable the responsible of the installations to verify compliance with the legal dose limits to the workers and ALARA goals. Thermoluminescent dosemeters (TLDs) are generally employed to assess the environmental and personnel doses. To completely characterize a TLD dosimetry system is fundamental to determine the Lowest Dose that the system is capable of measuring. As the amount of the light emitted by TLD material is a function of the time temperature profile (TTP), in the present study, the influence of the TTP on the Detection Threshold (MDD) of the LiF:Mg,Ti (TLD-100) detectors was evaluated. Eighteen different TTPs were tested for two different annealing processes: (I) utilization of the TTP itself and; (II) a microprocessor controlled oven annealing procedure. Results showed that TTP choice can influence significantly in the MDD values. The worst results were generally found for TLDs annealed by the TTP itself. The lack of pattern or the unexpected behavior to the influence of some parameters of the TTP on the calculated MDDs must be carefully investigated. Greater variations on the TTP parameters must be undertaken. Special attention must be also done on the methodology of calculating the MDDs. (author)

  11. Test of an albedo neutron dosimetry system: TLD calibration and readout procedure, neutron calibration, dosimetry properties, routine application

    International Nuclear Information System (INIS)

    Piesch, E.; Burgkhardt, B.

    1988-03-01

    The two-component albedo dosemeter in use consists of an universal boron-loaded plastic encapsulation, the beta and albedo neutron windows of which are adopted to the corresponding TLD system of the manufacturers Alnor, Harshaw, Panasonic and Vinten. Beside the TLD detectors the capsule may contain also track etch detectors. Within a BMU project the system was investigated by four governmental measurement services in the FRG with respect to its qualification for personnel monitoring with emphasis in the readout and calibration procedures for the TLD system, the evaluation technique for the estimation of the photon and neutron dose equivalent in routine monitoring and the calibration of the personnel dosemeter in stray neutron fields. The test has shown the readiness of the system to act in the application areas of nuclear power reactors and linacs behind heavy shieldings, in the fuel element cycle, use of fissile materials, criticality, use of radionuclide sources, high energy particle accelerators. The uncertainty due to energy dependence was found to be within a factor of 2 for a single application area. In the case of irradiations from the front half space the dose equivalent H'(10) is indicated sufficiently independent of the direction of the radiation incidence. After completion of the test the albedo dosemeter became the official neutron personnel dosemeter in the FRG. It allows the separate estimation of the dose equivalent of hard beta radiation, photon radiation and neutrons. (orig./HP) [de

  12. A Pb-TLD spectrometer to measure high energy photons in z-pinch experiments on the primary test stand

    International Nuclear Information System (INIS)

    Si, Fenni; Yang, Jianlun; Xu, Rongkun; Yuan, Xi; Huang, Zhanchang; Ye, Fan; Wang, Dong; Zhang, Chuanfei

    2017-01-01

    Highlights: • A Pb-TLD spectrometer has been developed to measure spectra of high energy photons in wire-array z pinches on PTS. • Energy spectra of high energy photons on PTS has been firstly obtained by unfolding programs developed with MATLAB code. • The energy of high energy x-ray on PTS is obtained to be mainly within the region of 100 keV to 1.3 MeV. - Abstract: A Pb-TLD spectrometer has been developed based on attenuation techniques to measure high energy photons in wire-array z-pinch experiments on the primary test stand (PTS). It is composed of a stack of 18 lead filters interspersed with 19 thermoluminescent dosimeters (TLD). A shield is constructed for the spectrometer and scattered radiation is reduced to less than 5% by the shield. Response functions of the spectrometer are calculated by MCNP5 for 0–2 MeV photons. Based on response functions and 19 dose data measured in experiments, energy spectra of high energy photons on PTS has been firstly obtained by unfolding programs developed with MATLAB code using iterative least square fit. Results show that energy peak locates within 200 keV and 300 keV, and the fluence decreases to background level at energy higher than 1.3 MeV.

  13. In-vivo dosimetry in radiotherapy: a comparison of the response of semiconductor and thermoluminescence (TLD700) dosemeters

    Energy Technology Data Exchange (ETDEWEB)

    Vynckier, S [Universite Catholique de Louvain, Brussels (Belgium). Cliniques Universitaires St. Luc; Greffe, J L; Loncol, T; Vanneste, F; Octave-Prignot, M; Denis, J M; De Patoul, N

    1995-12-01

    Semiconductor dosemeters and thermoluminescence dosemeters were calibrated in view of in-vivo dosimetry. Their response in a 8 MV photon beam and the respective correction factors for the treatment conditions were systematically studied. A total of 249 entrance and exit measurements with this dual detector combination were performed, mainly for treatments of the head and neck region. The resulting entrance and exit doses were compared with the expected doses at these positions, calculated on basis of the treatment and patient parameters. The results at the entrance showed a value of 1.010 (2.8% for the ratio of the measured to the calculated dose by diodes, 1.013) 4.9% for the ratio of the measured to the calculated dose by TLD and 1.003 (3.6% for the ratio of the measured dose by TLD to diodes. With respect the exit dose, the results were 0.998) 4.9%, 1.016 (7.7% and 1.019) 7.0% respectively after correction for the heterogeneity`s. Although the standard deviation for the TLD dosemeters is systematically larger than the standard deviation for the diodes, it is concluded that both dosemeters will yield similar results for-in-vivo dosimetry, if utilized under the same conditions.

  14. A Pb-TLD spectrometer to measure high energy photons in z-pinch experiments on the primary test stand

    Energy Technology Data Exchange (ETDEWEB)

    Si, Fenni; Yang, Jianlun; Xu, Rongkun; Yuan, Xi; Huang, Zhanchang; Ye, Fan; Wang, Dong; Zhang, Chuanfei, E-mail: sifenni@163.com

    2017-05-15

    Highlights: • A Pb-TLD spectrometer has been developed to measure spectra of high energy photons in wire-array z pinches on PTS. • Energy spectra of high energy photons on PTS has been firstly obtained by unfolding programs developed with MATLAB code. • The energy of high energy x-ray on PTS is obtained to be mainly within the region of 100 keV to 1.3 MeV. - Abstract: A Pb-TLD spectrometer has been developed based on attenuation techniques to measure high energy photons in wire-array z-pinch experiments on the primary test stand (PTS). It is composed of a stack of 18 lead filters interspersed with 19 thermoluminescent dosimeters (TLD). A shield is constructed for the spectrometer and scattered radiation is reduced to less than 5% by the shield. Response functions of the spectrometer are calculated by MCNP5 for 0–2 MeV photons. Based on response functions and 19 dose data measured in experiments, energy spectra of high energy photons on PTS has been firstly obtained by unfolding programs developed with MATLAB code using iterative least square fit. Results show that energy peak locates within 200 keV and 300 keV, and the fluence decreases to background level at energy higher than 1.3 MeV.

  15. Study of the influence of the time temperature profile on the minimum detectable dose of TLD-100

    International Nuclear Information System (INIS)

    Meireles, Leonardo S.; Lacerda, Marco Aurelio S.; Meira-Belo, Luiz C.; Ferreira, Hudson R.

    2013-01-01

    Monitoring of workers and workplaces is an integral part of any radiation protection programme (RPP). It is essential to demonstrate compliance with regulations that limit the allowable dose to the public from manmade sources and to enable the responsible of the installations to verify compliance with the legal dose limits to the workers and ALARA goals. Thermoluminescent dosemeters (TLDs) are generally employed to assess the environmental and personnel doses. To completely characterize a TLD dosimetry system is fundamental to determine the Lowest Dose that the system is capable of measuring. As the amount of the light emitted by TLD material is a function of the time temperature profile (TTP), in the present study, the influence of the TTP on the Detection Threshold (MDD) of the LiF:Mg,Ti (TLD-100) detectors was evaluated. Eighteen different TTPs were tested for two different annealing processes: (I) utilization of the TTP itself and; (II) a microprocessor controlled oven annealing procedure. Results showed that TTP choice can influence significantly in the MDD values. The worst results were generally found for TLDs annealed by the TTP itself. The lack of pattern or the unexpected behavior to the influence of some parameters of the TTP on the calculated MDDs must be carefully investigated. Greater variations on the TTP parameters must be undertaken. Special attention must be also done on the methodology of calculating the MDDs. (author)

  16. Status of services, overexposure and QAC in TLD PMS to defence

    International Nuclear Information System (INIS)

    Rathore, A.S.; Gupta, D.K.; Samaria, H.C.; Chouhan, R.L.; Mishra, M.; Goyal, J.K.; Gautam, M.; Kalla, R.

    2008-01-01

    Individual monitoring has always played an important role in radiological protection. There is continuous development in the field of dosimetry systems and many changes have taken place in last many years. The use of radiation for peaceful purposes is increasing with advancement of technological growth in the country. Thermo luminescence dosimeters (TLDs) have emerged as one of the best alternatives for personal monitoring. Defence sector has nearly 2100 persons, who are working in various Military Hospitals, Military Colleges, DRDO Labs, Defence Ordinance factories and many others CPMFs like CISF, BSF, who are likely to receive radiation doses. Defence Laboratory, Jodhpur is providing the TLD personal monitoring service since Jan 1999 as per the guideline by B.A.R.C. to all the institutions mentioned above. This paper brings out salient features of this service in terms of facility available, procedures fulfilling the requirement of accreditation, over exposure reported, quality measures adopted and quality assurance results conducted by BARC, utility and suggestions for such type of services. (author)

  17. PTTL Dose Re-estimation Applied to Quality Control in TLD-100 Based Personal Dosimetry

    International Nuclear Information System (INIS)

    Muniz, J.L.; Correcher, V.; Delgado, A.

    1999-01-01

    A new method for quality control of dose performance in Personal Dosimetry using TLD-100 is presented. This method consists of the application of dose reassessment techniques based on phototransferred thermoluminescence (PTTL). Reassessment is achieved through a second TL readout of the dosemeters worn by the controlled workers, after a reproducible UV exposure. Recent refinements in the PTTL technique developed in our laboratory allow reassessing doses as low as 0.2 mSv, thus extending the reassessment capability to the entire dose range that must be monitored in personal dosimetry. After a one month exposure, even purely environmental doses can be reassessed. This method can be applied for either re-estimation of single doses or of the total dose accumulated after a number of exposures and dose measurements. Several tests to reconfirm low doses in normal working conditions for personal dosimetry have been performed. Each test consisted of several cycles of exposure and TL evaluations and a final PTTL re-estimation of the total accumulated dose in those cycles. The results obtained always showed very good agreement between the sum of the partial doses and the total reassessed dose. The simplicity of the method and the possibility of re-evaluating the doses assessed to the workers employing their own dosemeters are advantageous features to be considered in designing systems for the determination of real performance in personal dosimetry. (author)

  18. Systematical and statistical errors in using reference light sources to calibrate TLD readers

    International Nuclear Information System (INIS)

    Burgkhardt, B.; Piesch, E.

    1981-01-01

    Three light sources, namely an NaI(Tl) scintillator + Ra, an NaI(Tl) scintillator + 14 C and a plastic scintillator + 14 C, were used during a period of 24 months for a daily check of two TLD readers: the Harshaw 2000 A + B and the Toledo 651. On the basis of light source measurements long-term changes and day-to-day fluctuations of the reader response were investigated. Systematical changes of the Toledo reader response of up to 6% during a working week are explained by nitrogen effects in the plastic scintillator light source. It was found that the temperature coefficient of the light source intensity was -0.05%/ 0 C for the plastic scintillator and -0.3%/ 0 C for the NaI(Tl) scintillator. The 210 Pb content in the Ra activated NaI(Tl) scintillator caused a time-dependent decrease in light source intensity of 3%/yr for the light source in the Harshaw reader. The internal light sources revealed a relative standard deviation of 0.5% for the Toledo reader and the Harshaw reader after respective reading times of 0.45 and 100 sec. (author)

  19. Measurement of dose to skin using TLD of several radiodiagnostic studies in San Jose, Costa Rica

    International Nuclear Information System (INIS)

    Mora, P.

    1998-01-01

    It is quantified the radiation doses on skin for several radiodiagnostic studies in patients of the Calderon Guardia Hospital in San Jose, Costa Rica at the period October 1997-September 1998 using thermoluminescent dosemeters TLD 100. The crystals receive the decoction standard procedures and they are arranged at the middle of the irradiation field. For a total of 973 radiodiagnostic studies it was found that the dose on skin in mGy are: 2.09 for thorax AP/AP, 5.33 for thorax LAT, 5.35 for skull AP/PA, 2.98 for skull LAT, 10.74 for abdomen, hips and pelvis, 6.20 for spines AP, 9.35 for spines LAT, 11.48 for lumbar columns AP, 29.99 for lumbar columns LAT and 6.87 for intravenous skin diagrams (first plate ap). It is produced thus the first reference bank for the national hospitals, which is compared with the orientation levels of doses for IAEA. Recommendations to diminish the collective doses through quality control programs are discussed, taking as goal to have got radiographs of excellent diagnostic quality, but with the less possible doses. (Author)

  20. External radiation monitoring in TAPS and RAPS environs (1980-81) using TLD

    International Nuclear Information System (INIS)

    Basu, A.S.; Nambi, K.S.V.; Sunta, C.M.

    1983-01-01

    Results of environmental external radiation monitoring using quarterly integrated TLD measurements are presented for environments of the Tarapur Atomic Power Station (TAPS) and the Rajasthan Atomic Power Station (RAPS) for the two year monitoring period (1980-81). The data fit into the unimodal log-normal distribution except for locations where gaseous radioactivity escaping from the plant makes a significant contribution. The average natural radiation background in TAPS and RAPS environment is estimated to be 59.6 +- 4.7 mR yr -1 and 65.1 +- 9.8 mR yr -1 respectively. Contribution from the plant superimposed over the natural level leads frequently to bi-normal distribution. The effect of stack-released gaseous radioactivity is seen in locations within 1.6 km of TAPS: for example Ghivoli village registered an excess of 9.3 mR yr -1 over the natural background. The quarterly background values indicate minor temporal and spatial variations which can be attributed to changes in natural as well as stack released radioactivity. (author)

  1. Thermoluminescent dosemeters (TLD) exposed to high fluxes of gamma radiation, thermal neutrons and protons

    International Nuclear Information System (INIS)

    Gambarini, G.; Martini, M.; Meinardi, F.; Raffaglio, C.; Salvadori, P.; Scacco, A.; Sichirollo, A.E.

    1996-01-01

    Thermoluminescent dosemeters (TLD), widely experimented and utilized in personal dosimetry, have some advantageous characteristics which induce one to employ them also in radiotherapy. The new radiotherapy techniques are aimed at selectively depositing a high dose in cancerous tissues. This goal is reached by utilising both conventional and other more recently proposed radiation, such as thermal neutrons and heavy charged particles. In these inhomogeneous radiation fields a reliable mapping of the spatial distribution of absorbed dose is desirable, and the utilized dosemeters have to give such a possibility without notably perturbing the radiation field with the materials of the dosemeters themselves. TLDs, for their small dimension and their tissue equivalence for most radiation, give good support in the mapping of radiation fields. After exposure to the high fluxes of therapeutic beams, some commercial TL dosemeters have shown a loss of reliability. An investigation has therefore be performed, both on commercial and on laboratory made phosphors, in order to investigate their behaviour in such radiation fields. In particular the thermal neutron and gamma ray mixed field of the thermal column of a nuclear reactor, of interest for Boron Neutron Capture Therapy (B.N.C.T.) and a proton beam, of interest for proton therapy, were considered. Here some results obtained with new TL phosphors exposed in such radiation fields are presented, after a short description of some radiation damage effect on commercial LiF TLDs exposed in the (n th ,γ) field of the thermal column of a reactor. (author)

  2. Reproducibility study of TLD-100 micro-cubes at radiotherapy dose level

    International Nuclear Information System (INIS)

    Rosa, Luiz Antonio R. da; Regulla, Dieter F.; Fill, Ute A.

    1999-01-01

    The precision of the thermoluminescent response of Harshaw micro-cube dosimeters (TLD-100), evaluated in both Harshaw thermoluminescent readers 5500 and 3500, for 1 Gy dose value, was investigated. The mean reproducibility for micro-cubes, pre-readout annealed at 100 deg. C for 15 min, evaluated with the manual planchet reader 3500, is 0.61% (1 standard deviation). When micro-cubes are evaluated with the automated hot-gas reader 5500, reproducibility values are undoubtedly worse, mean reproducibility for numerically stabilised dosimeters being equal to 3.27% (1 standard deviation). These results indicate that the reader model 5500, or, at least, the instrument used for the present measurements, is not adequate for micro-cube evaluation, if precise and accurate dosimetry is required. The difference in precision is apparently due to geometry inconsistencies in the orientation of the imperfect micro-cube faces during readout, requiring careful and manual reproducible arrangement of the selected micro-cube faces in contact with the manual reader planchet

  3. Personal dosimetry TLD 100 in orthopedic surgeons exposed to ionizing radiation in Bogota - Colombia

    International Nuclear Information System (INIS)

    Sierra C, B. Y.; Jimenez, Y.; Plazas, M. C.; Eslava S, J.; Groot R, H.

    2014-08-01

    Orthopedic surgeons should be considered as professionals occupationally exposed to ionizing radiation, for using C arc (fluoroscope) an equipment of X type radiation emission, during surgical procedures for imaging generation. Some health institutes, use of C arc under uncontrolled circumstances, such a lack of dosimetry control, incomplete or absence of personnel protective elements and protective measures, which in turn, lead to a high exposition to the personnel. Materials and methods. Study of double match cohort by age and gender, was conducted, in four health institutions of second and third level of attention in Bogota city. Personal dosimetry measurements with TLD-100 dosimetry crystals in both cohorts and environmental dosimetry in each of operation rooms used for orthopedic procedures, were carry out during six months of follow up. Dosimetry crystals were read in a Harshaw 4500 - Bicron equipment, in the Medical Physics Laboratory of National University of Colombia. Results. Dosimetry measurements are compatibles with those of occupationally exposed personnel 3.44 mSv/6 m CI 95% (1.66-3.99), even does not overpass ICRP recommendations, are higher as were expect at the beginning of the study. The median of effective accumulative dose in thorax is 3,4 mSv CI 95% (1,66-3,99), higher in comparison with neck value 2,7 mSv CI 95% (1,73-3,80) and hand dosimetry 1,42 mSv CI 95% (0,96-2,34). Conclusions: Orthopedic surgeons should be considered occupational exposed to ionizing radiation, who has to accomplish to the radiological protection measures, dosimetric follow up and maintenance of the used X ray equipment. It was confirm throughout this study that dosimetry shows higher levels as expected at the beginning of the study, compatible with occupationally exposed personnel. (Author)

  4. Long-term TLD measurements of environmental background radiation in the New York City Area

    International Nuclear Information System (INIS)

    Maiello, M.

    1994-11-01

    The results of month-long TLD measurements at seven locations within 150 km of New York City are reported for 12 years at a few locations and for up to 18 years at others. At some locations, multiple dosimeters were deployed to acquire concurrent indoor and outdoor measurements. The sites were varied and include an urban high-rise residence, three suburban backyards, a rural hillside, and the wooded outskirts of a nuclear power plant (nonoperational). Long-term mean dose rates in air ranged from 50.8 to 123.1 nGy h -1 (5.8 to 14.1 μR h -1 ) across the area. The typical seasonal dose rate in air variations are presented for two of the sites and are briefly discussed in terms of soil conditions. The data indicate that it is possible to achieve monthly variations from the long-term mean as high as 20 to 40%. One of these locations was monitored for indoor (2 floors) and outdoor air dose rates. This allowed for a time series comparison to be performed illustrating the changing contribution of terrestrial radiation to the total dose rate relative to the steady building material-derived radioactivity. This site also permitted the calculation of indoor/outdoor ratios for two floors. Another suburban location yielded an indoor/outdoor ratio using ground floor dose-rate-in-air measurements. Also presented are mean annual dose rates in air showing a long-term decrease at some locations. A statistical Kendall test was performed to quantify the magnitude of the decrease. A definitive explanation of this trend requires further study

  5. Measurement of Thyroid Dose by TLD arising from Radiotherapy of Breast Cancer Patients from Supraclavicular Field

    Directory of Open Access Journals (Sweden)

    Farhood B.

    2016-06-01

    Full Text Available Background: Breast cancer is the most frequently diagnosed cancer and the leading global cause of cancer death among women worldwide. Radiotherapy plays a significant role in treatment of breast cancer and reduces locoregional recurrence and eventually improves survival. The treatment fields applied for breast cancer treatment include: tangential, axillary, supraclavicular and internal mammary fields. Objective: In the present study, due to the presence of sensitive organ such as thyroid inside the supraclavicular field, thyroid dose and its effective factors were investigated. Materials and Methods: Thyroid dose of 31 female patients of breast cancer with involved supraclavicular lymph nodes which had undergone radiotherapy were measured. For each patient, three TLD-100 chips were placed on their thyroid gland surface, and thyroid doses of patients were measured. The variables of the study include shield shape, the time of patient’s setup, the technologists’ experience and qualification. Finally, the results were analyzed by ANOVA test using SPSS 11.5 software. Results: The average age of the patients was 46±10 years. The average of thyroid dose of the patients was 140±45 mGy (ranged 288.2 and 80.8 in single fraction. There was a significant relationship between the thyroid dose and shield shape. There was also a significant relationship between the thyroid dose and the patient’s setup time. Conclusion: Beside organ at risk such as thyroid which is in the supraclavicular field, thyroid dose possibility should be reduced. For solving this problem, an appropriate shield shape, the appropriate time of the patient’s setup, etc. could be considered.

  6. Response analysis of TLD-300 dosimeters in heavy-particle beams

    International Nuclear Information System (INIS)

    Loncol, Th.; Hamal, M.; Vynckier, S.; Scalliet, P.; Denis, J.M.; Wambersie, A.

    1996-01-01

    In vivo dosimetry is recommended as part of the quality control procedure for treatment verification in radiation therapy. Using thermoluminescence, such controls are planned in the p(65)+Be neutron and 85 MeV proton beams produced at the cyclotron at Louvain-La-Neuve and dedicated to therapy applications. A preliminary study of the peak 3 (150 deg. C) and peak 5 (250 deg. C) response of CaF 2 :Tm (TLD-300) to neutron and proton beams aimed to analyse the effect of different radiation qualities on the dosimetric behaviour of the detector irradiated in phantom. To broaden the range of investigation, the study was extended to an experimental C-12 heavy ion beam (95 MeV/nucleon). The peak 3 and 5 sensitivities in the neutron beam, compared to Co-60, varied little with depth. A major change of peak 5 sensitivity was observed for samples positioned under five leaves of the multi-leaf collimator. While peak 3 sensitivity was constant with depth in the unmodulated proton beam, peak 5 sensitivity increased by 15%. Near the Bragg peak, peak 3 showed the highest decrease of sensitivity. In the modulated proton beam, the sensitivity values were not significantly smaller than those measured in the unmodulated beam far from the Bragg peak region. The ratio of the heights of peak 3 and peak 5 decreased by 70% from the Co-60 reference radiation to the C-12 heavy-ion beam. This parameter was strongly correlated with the change of radiation quality. (author)

  7. Study of the OSL response of the CaF2:Dy (TLD-200) dosimeter

    International Nuclear Information System (INIS)

    Medeiros, Beatriz M.; Alencar, Marcus A.V. de

    2013-01-01

    The OSL dosimetry has become, in recent years, a successful technique in personal and environmental dosimetry due to high luminescence efficiency, excellent reproducibility, fast readout of signal and repeated and successive OSL measurements of the same dosimeter. Another factor that contributes to the increased use of OSL dosimetry is the use of the aluminum oxide doped with carbon (Al 2 O 3 :C) as dosimeter. Developed initially as thermoluminescent dosimeter, the Al 2 O 3 :C has an excellent OSL sensitivity, high efficiency, good linearity, low or no fading and excellent stability with respect to environmental conditions. However, the OSL dose response for aluminum oxide is linear only for low doses. For intermediate doses (doses in radiotherapy), the response is supralinear. For the values of high doses used in the processes of food irradiation and sterilization of surgical materials, the OSL signal of the aluminum oxide already saturated. Furthermore, the degree of supralinearity and the saturation value vary from sample to sample (∼ 30-300 Gy). Therefore, the use of aluminum oxide as OSL dosimeter is inappropriate in radiotherapy and in the irradiation industrial processes. The objective of this work is the study of the OSL properties of other dosimetric materials irradiated with values of intermediate and high dose to verify the applicability of the OSL dosimetry in radiotherapy and in the processes of food irradiation and sterilization of medical materials. The dosimetric material used in this work is the calcium fluoride doped with dysprosium (CaF 2 :Dy) produced by Harshaw and known commercially as TLD-200. The results demonstrate that the CaF 2 :Dy has OSL signal and the OSL dose response is linear in the range of 10 Gy to 300 Gy. Therefore, the dosimetry OSL with this dosimeter can be used in the evaluation of doses of the order of dozens to hundreds of grays. (author)

  8. Development and characterization of a three-dimensional radiochromic film stack dosimeter for megavoltage photon beam dosimetry.

    Science.gov (United States)

    McCaw, Travis J; Micka, John A; DeWerd, Larry A

    2014-05-01

    Three-dimensional (3D) dosimeters are particularly useful for verifying the commissioning of treatment planning and delivery systems, especially with the ever-increasing implementation of complex and conformal radiotherapy techniques such as volumetric modulated arc therapy. However, currently available 3D dosimeters require extensive experience to prepare and analyze, and are subject to large measurement uncertainties. This work aims to provide a more readily implementable 3D dosimeter with the development and characterization of a radiochromic film stack dosimeter for megavoltage photon beam dosimetry. A film stack dosimeter was developed using Gafchromic(®) EBT2 films. The dosimeter consists of 22 films separated by 1 mm-thick spacers. A Virtual Water™ phantom was created that maintains the radial film alignment within a maximum uncertainty of 0.3 mm. The film stack dosimeter was characterized using simulations and measurements of 6 MV fields. The absorbed-dose energy dependence and orientation dependence of the film stack dosimeter were investigated using Monte Carlo simulations. The water equivalence of the dosimeter was determined by comparing percentage-depth-dose (PDD) profiles measured with the film stack dosimeter and simulated using Monte Carlo methods. Film stack dosimeter measurements were verified with thermoluminescent dosimeter (TLD) microcube measurements. The film stack dosimeter was also used to verify the delivery of an intensity-modulated radiation therapy (IMRT) procedure. The absorbed-dose energy response of EBT2 film differs less than 1.5% between the calibration and film stack dosimeter geometries for a 6 MV spectrum. Over a series of beam angles ranging from normal incidence to parallel incidence, the overall variation in the response of the film stack dosimeter is within a range of 2.5%. Relative to the response to a normally incident beam, the film stack dosimeter exhibits a 1% under-response when the beam axis is parallel to the film

  9. TLD Postal service for quality audits of beams of Co-60 in reference conditions in Cuba; Servicio Postal TLD para auditorias de calidad de haces de Co-60 en condiciones de referencia en Cuba

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez L, S.; Walwyn S, G.; Alonso V, G. [CPHR, Calle 20 No. 4113 e/41 y 47, Playa, C.P. 11300, C. Habana (Cuba)]. e-mail: stefan@cphr.edu.cu

    2006-07-01

    Purpose: To describe the methodology and experience of the Secondary Laboratory of Dosimetric Calibration of Cuba in the establishment of the TLD Postal Service for quality audits of beams of Co-60 in reference conditions. Materials and methods: Through the Coordinated Project of Research (Contract 10794) its was bought 200 solid thermoluminescent detectors of LiF: Mg, Ti (TLD-100) in micro bars form with dimensions of 6 x 1 x 1 mm and of the JR 1152F type manufactured in China. All these detectors were identified individually with a serial number on one of its faces, using a graphite fine sheet. Those detectors for its irradiation are introduced in cylindrical plastic capsules developed and used by the International Atomic Energy Agency (IAEA) in the Audit Postal Service of Dose IAEA/WHO, the capsules have one cavity equal to 3 mm for that is necessary to recover this cavity with a fine plastic tube so that the detectors remain immobile during the irradiation. The method used to determine the individual sensitivity of the thermoluminescent detectors is: to irradiate a detectors group (100 micro bars) 4 times in those same geometric conditions, with the same irradiation history and reading, then it is determine for each detector a sensitivity factor equal to the average of those readings obtained for the 4 irradiation cycles for each i detector among the average of all the reading values obtained during the 4 cycles. The thermoluminescent signal is obtained with a Harshaw 2000C/B reader manual. Results: The satisfactory results obtained in the verification of the calibration of the TLD system, using the reference irradiation service of the Seibersdorf Dosimetry Laboratory of the IAEA in three different years are shown. The results of the audits carried out to the different radiotherapy services of the country in different years are also presented. Conclusions: The experience with the detectors acquired in the project demonstrates that with an appropriate

  10. Effective dose assessment in the maxillofacial region using thermoluminescent (TLD) and metal oxide semiconductor field-effect transistor (MOSFET) dosemeters: a comparative study.

    Science.gov (United States)

    Koivisto, J; Schulze, D; Wolff, J; Rottke, D

    2014-01-01

    The objective of this study was to compare the performance of metal oxide semiconductor field-effect transistor (MOSFET) technology dosemeters with thermoluminescent dosemeters (TLDs) (TLD 100; Thermo Fisher Scientific, Waltham, MA) in the maxillofacial area. Organ and effective dose measurements were performed using 40 TLD and 20 MOSFET dosemeters that were alternately placed in 20 different locations in 1 anthropomorphic RANDO(®) head phantom (the Phantom Laboratory, Salem, NY). The phantom was exposed to four different CBCT default maxillofacial protocols using small (4 × 5 cm) to full face (20 × 17 cm) fields of view (FOVs). The TLD effective doses ranged between 7.0 and 158.0 µSv and the MOSFET doses between 6.1 and 175.0 µSv. The MOSFET and TLD effective doses acquired using four different (FOV) protocols were as follows: face maxillofacial (FOV 20 × 17 cm) (MOSFET, 83.4 µSv; TLD, 87.6 µSv; -5%); teeth, upper jaw (FOV, 8.5 × 5.0 cm) (MOSFET, 6.1 µSv; TLD, 7.0 µSv; -14%); tooth, mandible and left molar (FOV, 4 × 5 cm) (MOSFET, 10.3 µSv; TLD, 12.3 µSv; -16%) and teeth, both jaws (FOV, 10 × 10 cm) (MOSFET, 175 µSv; TLD, 158 µSv; +11%). The largest variation in organ and effective dose was recorded in the small FOV protocols. Taking into account the uncertainties of both measurement methods and the results of the statistical analysis, the effective doses acquired using MOSFET dosemeters were found to be in good agreement with those obtained using TLD dosemeters. The MOSFET dosemeters constitute a feasible alternative for TLDs for the effective dose assessment of CBCT devices in the maxillofacial region.

  11. Evaluating secondary neutron doses of a refined shielded design for a medical cyclotron using the TLD approach

    International Nuclear Information System (INIS)

    Lin, Jye-Bin; Tseng, Hsien-Chun; Liu, Wen-Shan; Lin, Ding-Bang; Hsieh, Teng-San; Chen, Chien-Yi

    2013-01-01

    An increasing number of cyclotrons at medical centers in Taiwan have been installed to generate radiopharmaceutical products. An operating cyclotron generates immense amounts of secondary neutrons from reactions such the 18 O(p, n) 18 F, used in the production of FDG. This intense radiation can be hazardous to public health, particularly to medical personnel. To increase the yield of 18 F-FDG from 4200 GBq in 2005 to 48,600 GBq in 2011, Chung Shan Medical University Hospital (CSMUH) has prolonged irradiation time without changing the target or target current to meet requirements regarding the production 18 F. The CSMUH has redesigned the CTI Radioisotope Delivery System shield. The lack of data for a possible secondary neutron doses has increased due to newly designed cyclotron rooms. This work aims to evaluate secondary neutron doses at a CTI cyclotron center using a thermoluminescent dosimeter (TLD-600). Two-dimensional neutron doses were mapped and indicated that neutron doses were high as neutrons leaked through self-shielded blocks and through the L-shaped concrete shield in vault rooms. These neutron doses varied markedly among locations close to the H 2 18 O target. The Monte Carlo simulation and minimum detectable dose are also discussed and demonstrated the reliability of using the TLD-600 approach. Findings can be adopted by medical centers to identify radioactive hot spots and develop radiation protection. - Highlights: • Neutron doses were verified using TLD approach. • Neutron doses were increased at cyclotron centers. • Revised L-shaped shield suppresses effectively the neutrons. • Neutron dose can be attenuated to 1.13×10 6 %

  12. Analysis on the evaluation of dose of the team reader TLD SOLARO, post-adjustment of the heating resistance marks

    International Nuclear Information System (INIS)

    Morales C, M.

    2000-09-01

    This report describes the process carried out in the area of personal dosimetry as for different evaluations carried out in the team reader TLD SOLARO it marks, which evaluates chips of LiF and cards containing two pellets of LiF-700, to determine if after having carried out an adjustment in the heating system the dose evaluations they continue being acceptable, that is to say, the evaluated doses stay inside the error margin allowed for the case of external individual monitoring

  13. Obtention of thermoluminescent efficiencies by means of irradiation of TLD-100 dosemeters with proton beams helium and carbon

    International Nuclear Information System (INIS)

    Avila, O.; Rodriguez V, M.; Aviles, P.; Gamboa de Buen, I.; Buenfil, A.E.; Ruiz T, C.; Brandan, M.E.

    2002-01-01

    In this work, the advances of a serial of measurements of relative efficiency thermoluminescent of heavy charged particles (PCP) with respect to gamma radiation for TLD-100, dosemeters of LiF: Mg,Ti manufactured by the Harshaw-Bicron company are reported. The PCP are essentials in the implementation of dosimetry associated with medical applications. The measurements before gamma radiation were carrying out using the Vickrad irradiator of the National Institute of Nuclear Research at dose of 1.663 Gy. The measures which are reported about protons, helium and carbon were realized using the Pelletron accelerator of the Physics Institute of the UNAM. (Author)

  14. In vivo TLD-measurement of the radiation burden after intake of sup(99m)Tc-labelled compounds

    International Nuclear Information System (INIS)

    Kletter, K.; Frischauf, H.; Dudczak, R.; Nowotny, R.

    1978-01-01

    Organ and whole-body radiation doses by sup(99m)Tc labelled preparations were measured on patients subjected to scintigraphy of liver (+spleen), thyroid of kidneys. Body surface doses were determined by means of TLD-100 (LiF) dosimeters. From these values organ doses were calculated by inference from surface and organ measurements on a Remcal - Alderson phantom which also served to examine the influence of variable fat layers on the surface doses. The results were compared with data calculated from pharmacokinetic measurements of organ uptake as well as blood and urine activity. Both methods gave corresponding results. (author)

  15. Film Reviews.

    Science.gov (United States)

    Lance, Larry M.; Atwater, Lynn

    1987-01-01

    Reviews four Human Sexuality films and videos. These are: "Personal Decisions" (Planned Parenthood Federation of America, 1985); "The Touch Film" (Sterling Production, 1986); "Rethinking Rape" (Film Distribution Center, 1985); "Not A Love Story" (National Film Board of Canada, 1981). (AEM)

  16. SU-E-T-594: Out-Of-Field Neutron and Gamma Dose Estimated Using TLD-600/700 Pairs in the Wobbling Proton Therapy System

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y [College of Medicine, Chang Gung University, Linkou, Taoyuan, Taiwan (China); Lin, Y [College of Medicine, Chang Gung University, Linkou, Taoyuan, Taiwan (China); Medical Physics Research Center, Institute for Radiological Research, Chang Gung University / Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan (China); Chen, H [College of Medicine, Chang Gung University, Linkou, Taoyuan, Taiwan (China); Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan (China); Tsai, H [College of Medicine, Chang Gung University, Linkou, Taoyuan, Taiwan (China); Medical Physics Research Center, Institute for Radiological Research, Chang Gung University / Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan (China); Healthy Aging Research Center, Chang Gung University, Linkou, Taoyuan, Taiwan (China)

    2015-06-15

    Purpose: Secondary fast neutrons and gamma rays are mainly produced due to the interaction of the primary proton beam with the beam delivery nozzle. These secondary radiation dose to patients and radiation workers are unwanted. The purpose of this study is to estimate the neutron and gamma dose equivalent out of the treatment volume during the wobbling proton therapy system. Methods: Two types of thermoluminescent (TL) dosimeters, TLD-600 ({sup 6}LiF: Mg, Ti) and TLD-700 ({sup 7}LiF: Mg, Ti) were used in this study. They were calibrated in the standard neutron and gamma sources at National Standards Laboratory. Annealing procedure is 400°C for 1 hour, 100°C for 2 hours and spontaneously cooling down to the room temperature in a programmable oven. Two-peak method (a kind of glow curve analysis technique) was used to evaluate the TL response corresponding to the neutron and gamma dose. The TLD pairs were placed outside the treatment field at the neutron-gamma mixed field with 190-MeV proton beam produced by the wobbling system through the polyethylene plate phantom. The results of TLD measurement were compared to the Monte Carlo simulation. Results: The initial experiment results of calculated dose equivalents are 0.63, 0.38, 0.21 and 0.13 mSv per Gy outside the field at the distance of 50, 100, 150 and 200 cm. Conclusion: The TLD-600 and TLD-700 pairs are convenient to estimate neutron and gamma dosimetry during proton therapy. However, an accurate and suitable glow curve analysis technique is necessary. During the wobbling system proton therapy, our results showed that the neutron and gamma doses outside the treatment field are noticeable. This study was supported by the grants from the Chang Gung Memorial Hospital (CMRPD1C0682)

  17. SU-E-T-594: Out-Of-Field Neutron and Gamma Dose Estimated Using TLD-600/700 Pairs in the Wobbling Proton Therapy System

    International Nuclear Information System (INIS)

    Chen, Y; Lin, Y; Chen, H; Tsai, H

    2015-01-01

    Purpose: Secondary fast neutrons and gamma rays are mainly produced due to the interaction of the primary proton beam with the beam delivery nozzle. These secondary radiation dose to patients and radiation workers are unwanted. The purpose of this study is to estimate the neutron and gamma dose equivalent out of the treatment volume during the wobbling proton therapy system. Methods: Two types of thermoluminescent (TL) dosimeters, TLD-600 ( 6 LiF: Mg, Ti) and TLD-700 ( 7 LiF: Mg, Ti) were used in this study. They were calibrated in the standard neutron and gamma sources at National Standards Laboratory. Annealing procedure is 400°C for 1 hour, 100°C for 2 hours and spontaneously cooling down to the room temperature in a programmable oven. Two-peak method (a kind of glow curve analysis technique) was used to evaluate the TL response corresponding to the neutron and gamma dose. The TLD pairs were placed outside the treatment field at the neutron-gamma mixed field with 190-MeV proton beam produced by the wobbling system through the polyethylene plate phantom. The results of TLD measurement were compared to the Monte Carlo simulation. Results: The initial experiment results of calculated dose equivalents are 0.63, 0.38, 0.21 and 0.13 mSv per Gy outside the field at the distance of 50, 100, 150 and 200 cm. Conclusion: The TLD-600 and TLD-700 pairs are convenient to estimate neutron and gamma dosimetry during proton therapy. However, an accurate and suitable glow curve analysis technique is necessary. During the wobbling system proton therapy, our results showed that the neutron and gamma doses outside the treatment field are noticeable. This study was supported by the grants from the Chang Gung Memorial Hospital (CMRPD1C0682)

  18. Production of LiF films for dosimetric thermoluminescence application

    International Nuclear Information System (INIS)

    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 2 NaF and Cu F 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 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 2 : LiF; Mg F 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 2 : LiF: Mg F 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 2 layer to the LiF layer. The TL volumetric sensitivity of these

  19. Use of TL - dosimeters of TLD - 500K type for precision estimation of spatial distributions of mixed dose fields in 'Ukryttia' conditions

    CERN Document Server

    Lagutin, I G; Ershova, N N

    2003-01-01

    In some works being currently carried out in ISTC 'Ukryttia' divisions within the framework of 'Complex program of works at 'Ukryttia' object', a necessary arose to estimate local values of radiation dose fields of mixed type (beta + gamma). The most convenient tool for estimation of local values of long - term integrals of such doses are dosimeters fabricated on the basis of thermoluminescent detectors (TLD) having small sensitive volume under sufficient radiating capacity, convenient performance and high reproducibility of results. It was offered to use TL - detectors of TLD-500K type on the basis of sapphire monocrystal (alpha-Al sub 2 O sub 3).

  20. Difficulty in estimation of dose for the abnormal patterns of the TLD disc readings - need investigation and improvement in work practices

    International Nuclear Information System (INIS)

    Madhumita, B.; Ande, C.D.; Sneha, C.; Bakshi, A.K.; Datta, D.

    2018-01-01

    TLD badge based on CaSO 4 :Dy detector used for external radiation monitoring of occupational workers of radiation facilities in India plays a vital role in radiation protection program. Energy and type of radiation in the work-field can be well identified from the dose evaluation algorithm. Algorithm developed earlier use the set of disc ratio from the three disc readings of the TLD badge to arrive at the dose and the type of radiation. Algorithm fails to estimate the dose for the abnormal patterns. The paper discusses the root cause of the abnormal patterns and investigation followed to arrive the estimation of dose

  1. Image-guided method for TLD-based in vivo rectal dose verification with endorectal balloon in proton therapy for prostate cancer

    International Nuclear Information System (INIS)

    Hsi, Wen C.; Fagundes, Marcio; Zeidan, Omar; Hug, Eugen; Schreuder, Niek

    2013-01-01

    Purpose: To present a practical image-guided method to position an endorectal balloon that improves in vivo thermoluminiscent dosimeter (TLD) measurements of rectal doses in proton therapy for prostate cancer. Methods: TLDs were combined with endorectal balloons to measure dose at the anterior rectal wall during daily proton treatment delivery. Radiopaque metallic markers were employed as surrogates for balloon position reproducibility in rotation and translation. The markers were utilized to guide the balloon orientation during daily treatment employing orthogonal x-ray image-guided patient positioning. TLDs were placed at the 12 o'clock position on the anterior balloon surface at the midprostatic plane. Markers were placed at the 3 and 9 o'clock positions on the balloon to align it with respect to the planned orientation. The balloon rotation along its stem axis, referred to as roll, causes TLD displacement along the anterior-posterior direction. The magnitude of TLD displacement is revealed by the separation distance between markers at opposite sides of the balloon on sagittal x-ray images. Results: A total of 81 in vivo TLD measurements were performed on six patients. Eighty-three percent of all measurements (65 TLD readings) were within +5% and −10% of the planning dose with a mean of −2.1% and a standard deviation of 3.5%. Examination of marker positions with in-room x-ray images of measured doses between −10% and −20% of the planned dose revealed a strong correlation between balloon roll and TLD displacement posteriorly from the planned position. The magnitude of the roll was confirmed by separations of 10–20 mm between the markers which could be corrected by manually adjusting the balloon position and verified by a repeat x-ray image prior to proton delivery. This approach could properly correct the balloon roll, resulting in TLD positioning within 2 mm along the anterior-posterior direction. Conclusions: Our results show that image-guided TLD

  2. Calibration of TLD badge to photons of energies above 6 MeV encountered in nuclear reactors

    International Nuclear Information System (INIS)

    Pradhan, A.S.; Bakshi, A.K.

    1999-01-01

    Response of CaSO 4 :Dy Teflon discs based TLD badge has been evaluated for radiation fields having photons of energy above 6 MeV, often encountered in nuclear power plants. Gamma ray response of the TLD disc under metal filter in the badge (used for evaluation of gamma ray doses) was found to increase by about 10% to photons above 6 MeV as compared to the response for reference calibration to 60 Co gamma rays. Response of discs under the open window and the plastic filter was found to be only 40-60% of that under metal filter. Thus, while measurement of whole body dose is not affected seriously, the estimation of beta dose in the mixed fields of high energy gamma rays and beta rays could be in serious error. In the above fields for situations having beta doses of about 1.65 times the gamma ray doses, the present use of dose evaluation will record beta dose as zero, a serious under estimation of beta ray doses. Study also provides an explanation to an anomalous situation where reading under window or plastic filter is much less than that under metal filter. These aspects of personal dosimetry need attention. (author)

  3. Design of photon energy compensation filters for the new four element CaSO4:Dy TLD badge

    International Nuclear Information System (INIS)

    Mishra, D.R.; Kulkarni, M.S.; Pradeep, Ratna; Kannan, S.

    2001-01-01

    A new four element TLD badge using CaSO 4 :Dy is being developed for the estimation of personal dose equivalents Hp(10) and Hp(0.07) and to discriminate them in the mix field (low energy x-ray and high energy γ-ray). Design of energy compensation filters for the new TLD badge is discussed. The total metal filter thickness is kept less than 1 mm. The first and second elements of the badge are planned to be open and plastic (≅180 gm/cm 2 ) window. For the third element a combination of 0.2 mm Sn + 0.7mm Cu + 0.1 mm Al with mass thickness ≅ 1100 mg/cm 2 is proposed which gives energy dependent response similar to Hp(10) within ± 20% (above 80 keV). For the fourth dosimeter a filter combination of 0.4 mm Al + 0.07 mm Sn is proposed which gives Hp(10)xR response for diagnostic x-rays within ± 10% in the mix field. (author)

  4. Lateral vibration behavior analysis and TLD vibration absorption design of the soft yoke single-point mooring system

    Science.gov (United States)

    Lyu, Bai-cheng; Wu, Wen-hua; Yao, Wei-an; Du, Yu

    2017-06-01

    Mooring system is the key equipment of FPSO safe operation. The soft yoke mooring system is regarded as one of the best shallow water mooring strategies and widely applied to the oil exploitation in the Bohai Bay in China and the Gulf of Mexico. Based on the analysis of numerous monitoring data obtained by the prototype monitoring system of one FPSO in the Bohai Bay, the on-site lateral vibration behaviors found on the site of the soft yoke subject to wave load were analyzed. ADAMS simulation and model experiment were utilized to analyze the soft yoke lateral vibration and it was determined that lateral vibration was resonance behaviors caused by wave excitation. On the basis of the soft yoke longitudinal restoring force being guaranteed, a TLD-based vibration damper system was constructed and the vibration reduction experiments with multi-tank space and multi-load conditions were developed. The experimental results demonstrated that the proposed TLD vibration reduction system can effectively reduce lateral vibration of soft yoke structures.

  5. Glow-peak stability in 6LiF:Mg, Ti (TLD-600) exposed to a Fe-ion beam

    International Nuclear Information System (INIS)

    Yasuda, Hiroshi

    2001-01-01

    The stability of glow peaks in 6 LiF:Mg, Ti (TLD-600) exposed to a high-energy Fe-ion beam was examined in comparison to 137 Cs γ-ray irradiation under changing annealing conditions. The peak areas induced by the Fe ions were much smaller than those by γ-rays. The sizes and positions of peaks 3-5 in Fe-ion irradiated samples were hardly changed after post-annealing at 100 deg C x 30 min, regardless of the pre-annealing conditions (fast quenching or subsequent pre-annealing at 100 deg C x 2 h). Whereas, the peaks in γ-ray irradiated samples were notably affected by post-annealing; the peak positions and peak-area sizes changed in different ways depending on the pre-annealing conditions. The effects of post-annealing on peak 6 were identical for Fe ions and γ-rays. These facts suggest that peaks 3-5 in TLD-600 comprised both stable and unstable luminescent centers, and that the latter part would be easily depleted in highly dense ionization. (author)

  6. Dosimetric evaluation of the response of the TLD-100 dosemeters in the IMRT technique by 'Step and Shoot'

    International Nuclear Information System (INIS)

    Vasquez, J.; Benavides, S.O.

    2005-01-01

    We show the results of the dosimetry response of LiF thermoluminescent crystals: TLD-100, where they were radiated in a linear accelerator Siemens Primus Hl using the Intensity Modulated Radiation Therapy (IMRT) by step and shoot technique. Previous to the crystals calibration and response evaluation, the acceptation procedures recommended by the TG-53 protocol for validation of the technique were carried out. The planning system utilized was the Theraplan Plus 3.8, using the algorithm of Pencil Kernel. The register and verification system was Lantis 5.2. The response curve of dose versus charge was obtained from the readings of the TLD in a Harshaw 3500. The crystals were radiated in a Bench- Marck phantom with doses previously determined by using ionization chambers for square radiation fields, in a beam with a 0.68 TPR20,10 corresponding to 6 MV of energy. We compare the response of these through of radiation of segmented fields in a Anthropomorphic phantom and the calculated doses by the planning system. The results obtained in the crystals response show deviations less than 5 % between the measured dose and the calculated dose in the zones of low gradient. It allows its implementation like routine control of quality by IMRT. (Author)

  7. Effect of quality control implementation on image quality of radiographic films and irradiation doses to patients

    International Nuclear Information System (INIS)

    Cheng Yuxi; Zhou Qipu; Ge Lijuan; Hou Changsong; Qi Xuesong; Yue Baorong; Wang Zuoling; Wei Kedao

    1999-01-01

    Objective: To study the changes in the image quality of radiographic films and the irradiation doses to patients after quality control (QC) implementation. Methods: The entrance surface doses (ESD) to patients measured with TLD and the image quality of radiographic films were evaluated on the basis of CEC image quality criteria. Results: The ESD to patients were significantly reduced after QC implementation (P 0.05), but the post-QC image quality was significantly improved in chest PA, lumbar spine AP and pelvis AP(P0.01 or P<0.05). Conclusion: Significantly reduced irradiation dose with improved image quality can be obtained by QC implementation

  8. Determination of the dose in eyes lens by TLD, in PET/CT by technicians in PET/CT service; Determinacion de la dosis en cristalino por medio de TLD, en personal tecnico de servicio PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Marino, Emiliano A., E-mail: eam.marino@gmail.com [Universidad Nacional de Cuyo (UNC), Rio Negro (Argentina). Instituto Balseiro; Arenas, German M. [Fundacion Escuela de Medicina Nuclear (FUESMEN), Mendoza (Argentina)

    2013-11-01

    This work was supported, on the one hand, in a part of the project ORAMED which consisted of a design of a TLD dosimeter for measurements of Hp (3) in areas close to the lens, for interventional radiology physicians. On the other hand, Berhens work proposes using calibrated TLDs Hp (0.07) and Hp (10) to estimate Hp (3) crystal. This resulted in dosimeters calibrated using Hp (10) slab, and mount them on glasses, to estimate the dose to the lens of the technical staff of the Service PET / CT. The value obtained 29mSv/year of Lens Dose Equivalent exceeds the recommended limit. We also demonstrate that, under the current working conditions, the values of Hp (3) reported from whole body dosimeter does not represent faithfully the lens dose.

  9. 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)

  10. Thermoluminescence of pure LiF and Lif (TLD-100) irradiated at room temperature; Termoluminiscencia en LiF puro y LiF dosimetrico (TLD-100), irradiados a temperatura ambiente

    Energy Technology Data Exchange (ETDEWEB)

    Sagastibelza Chivite, F

    1980-07-01

    The thermoluminescence of pure LiF and LiF (TLD-100) crystals irradiated at room temperature with x - or gamma-rays has been studied up to 460 degree centigree. For most of the glow peaks found the kinetics, preexponential factors and activation energies have been determined. These parameters have been obtained by means of the isothermal method. The study of the thermal annealing of the radiation induced F and Z centres has allow to show that there is a correlation among the glow peaks and the annealing stages of these centres. It is concluded that the F and Z - centres play the role of recombination centres for halogen interstitial atom thermally released from traps. Light emission occurs in this recombination. (Author) 120 refs.

  11. Metal filters for the compensation of photon energy dependence of the response of CaSO4: Dy - Teflon TLD Discs

    International Nuclear Information System (INIS)

    Pradhan, A.S.; Bhatt, R.C.

    1979-01-01

    Metal filters of aluminium, stainless steel, copper, cadmium, tin and lead were studied for compensation of the photon energy dependence of the response of CaSO 4 : Dy Teflon TLD Discs. It was found that metals such as cadmium and tin (which are normally used for this purpose) with their K absorption edges around 30 keV, are poor compensators of photon energy dependence. However, if either cadmium or tin is used in combination with either copper or stainless steel (with the lower Z filter nearer to the TLD dosimeter disc) a better compensation of photon energy dependence is achieved. Consequently, for personnel monitoring of X and gamma radiations, a TLD badge with CaSO 4 : Dy Teflon TLD discs and two sets of combination filters has been recommended. In the range of 27 keV -1.25 MeV this badge offers a photon energy response which varies within +-15%. This is a considerable improvement on the corresponding limits of +-65% on using a single filter. (orig.)

  12. Effective dose assessment in the maxillofacial region using thermoluminescent (TLD) and metal oxide semiconductor field-effect transistor (MOSFET) dosemeters: a comparative study

    NARCIS (Netherlands)

    Koivisto, J.; Schulze, D.; Wolff, J.E.H.; Rottke, D.

    2014-01-01

    Objectives: The objective of this study was to compare the performance of metal oxide semiconductor field-effect transistor (MOSFET) technology dosemeters with thermoluminescent dosemeters (TLDs) (TLD 100; Thermo Fisher Scientific, Waltham, MA) in the maxillofacial area. Methods: Organ and effective

  13. Relative thermoluminescent efficiencies proton/gamma and helium/gamma of peaks of high temperature in TLD-100 dosemeters; Eficiencias termoluminiscentes relativas proton/gamma y helio/gamma de picos de alta temperatura en dosimetros TLD-100

    Energy Technology Data Exchange (ETDEWEB)

    Flores M, E. [UNAM, Facultad de Ciencias, 04510 Mexico D.F. (Mexico)

    2007-07-01

    The increase of the applications of ion beams in radiotherapy treatments has generated interest in the study of the thermoluminescent materials (TL) that allow to determine the applied doses. A way to quantify the TL response from these materials to ions is by means of the relative thermoluminescent efficiency. In the group of Thermoluminescent dosimetry of the Institute of Physics of the UNAM (IFUNAM) the thermoluminescent response of the TLD-100 dosemeters has been studied, which present a glow curve characteristic with several peaks that correspond to traps and luminescent centers in the material. The stable peaks know each other as 4, 5, 6a, 6b, 7, 8, 9 and 10. The efficiencies should be measured using the response so much to the radiation of interest (in this case protons and helium ions) as the response to gamma radiation. In previous works with ions of low energy taken place in the Pelletron accelerator of the IFUNAM was only measured the TL efficiency for the peak 5 and the total signal. It had not been possible to measure the efficiency of the peaks of high temperature (6a-10) because, for the gamma radiation, the peaks of high temperature show very small signals; however, recently Massillon carries out measures of efficiency TL of peaks of high temperature for ions of intermediate energy using a protocol special of reading and of deconvolution that allows to measure the signals coming from the peaks of high temperature. In this work is implemented this same protocol to complete the study of TL efficiencies at low energy of protons and helium and to determine if the values of efficiency depend on the used reading protocol. For it is reported it measures of the relative efficiency of the peaks of high temperature from the TLD-100 exposed to protons of 1.5 MeV and nuclei of helium of 3 and 7.5 MeV. (Author)

  14. Measure of the attenuation curve of a beam of X-rays with TLD-100 dosimeters of LiF; Medicion de la curva de atenuacion de un haz de rayos X con dosimetros TLD-100 de LiF

    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, Cordoba (Argentina); Germanier, A. [Ministerio de Ciencia y Tecnologia, Ceprocor, Unidad de Estudios Fisicos, Alvarez de Arenas 230, X5004AAP Barrio Juniors, Cordoba (Argentina); Delgado, V. [Universidad Complutense de Madrid, Departamento de Fisica Medica, Ciudad Universitaria, 28040 Madrid (Spain)

    2011-10-15

    The attenuation curve of a beam of X-rays represents the beam intensity in function of the attenuator thickness interposed between the source and the detector. To know with the major possible precision the attenuation curve is indispensable in procedures of spectral reconstruction. Their periodic measuring also offers valuable information on the correct operation of a tube of X-rays, diagnostic or therapy, when not have a specific detector for that activity. In this work was measured the attenuation curve of a tube of X-rays operated to 50 kV and 0.5 ma, using existent elements in any diagnostic or therapy laboratory with radiations. In the measures commercial aluminum foil was used, bent until 24 times and thermoluminescent dosimeters TLD 100 - LiF. Also, for comparison, was measured this attenuation curve with an ionization chamber brand Capintec model 192. Was determined by X-rays fluorescence the composition of the aluminium foil, since the present elements in the alloy can to affect the form of the attenuation curve. It is interesting to observe that these elements are in very low proportion (ppm) that they do not alter the attenuation capacity of the pure aluminium. Finally in a precision balance we weigh a big piece (30 cm x 100 cm) of aluminium foil and we obtained the thickness in g/c m2. It is possible to obtain attenuation curves of a beam of X-rays, with a high precision procedure and reproducibility. The use of TLD-100 dosimeters of LiF or similar makes that this activity was also quick and simple. (Author)

  15. Use of lead aprons - further considerations of estimation of doses and conditions of acute exposures of TLD badge in diagnostic x-ray institutions

    International Nuclear Information System (INIS)

    Pradhan, A.S.; Chatterjee, S.

    2003-01-01

    In the recent study the authors reported that the exposure conditions of the use of the TLD badge, whether worn under or over the lead apron could be estimated from the readout of the TLD badge used in X-ray diagnostic departments. The effectiveness of lead aprons procured from different suppliers having the same value of quoted nominal lead equivalence was found to vary severely and this indicated some limitation in the applicability of the method of evaluation of exposure conditions of the badge. The transmission factors for the lead aprons varied up to a factor of 15 for the same value of quoted nominal lead equivalence procured from three different suppliers. This is of serious consequences in radiation protection and attracts attention for quality control. An error in the estimation of the exposure conditions of the TLD badge could lead to an underestimation of doses up to 4 times using the prevalent method. The estimation of the actual doses of radiation workers in the cases of over-exposures for the situations of the use of the TLD badge over the lead apron showed that the variation in the quality of lead aprons could be wrong in the range from 1.6 to 25 times even if the kVp of the machine is exactly known. Therefore, attempt should not be made to estimate the actual doses under lead apron from the readout of the TLD badge worn over the apron, as the real values of the transmission factors of the aprons and kVp of the X-ray machine may not be available. (author)

  16. Quality Assurance in Individual Monitoring: 10 Years of Performance Monitoring of the TLD Based TNO Individual Monitoring Service (invited paper)

    International Nuclear Information System (INIS)

    Dijk, J.W.E. van

    1998-01-01

    The QA subscription forms the nucleus of the Quality Assurance (QA) programme of the TLD-based Individual Monitoring Service of TNO-CSD. This QA subscription is the subscription of a dummy customer to the service. As this customer is treated exactly like a normal customer, all aspects of the service are monitored by the QA subscription. An overview is given of 10 years of monitoring the performance of the service. Various improvements over the past decade have resulted in a standard deviation in a low dose measurement of 0.01 mSv and a relative standard deviation at higher doses of 5%. These figures represent the performance under routine circumstances and thus include variations due to variations in the natural background from place to place and, for example, due to transport. (author)

  17. Determination of the dose in eyes lens by TLD, in PET/CT by technicians in PET/CT service

    International Nuclear Information System (INIS)

    Marino, Emiliano A.

    2013-01-01

    This work was supported, on the one hand, in a part of the project ORAMED which consisted of a design of a TLD dosimeter for measurements of Hp (3) in areas close to the lens, for interventional radiology physicians. On the other hand, Berhens work proposes using calibrated TLDs Hp (0.07) and Hp (10) to estimate Hp (3) crystal. This resulted in dosimeters calibrated using Hp (10) slab, and mount them on glasses, to estimate the dose to the lens of the technical staff of the Service PET / CT. The value obtained 29mSv/year of Lens Dose Equivalent exceeds the recommended limit. We also demonstrate that, under the current working conditions, the values of Hp (3) reported from whole body dosimeter does not represent faithfully the lens dose

  18. Doses Due to the South Atlantic Anomaly During the Euromir'95 Mission Measured by an On-Board TLD System

    International Nuclear Information System (INIS)

    Deme, S.; Apathy, I.; Hejja, I.; Lang, E.; Feher, I.; Reitz, G.

    1999-01-01

    During the Euromir'95 mission, a specially designed microprocessor-controlled thermoluminescent detector (TLD) system, called the 'Pille'95', was used by ESA astronaut Thomas Reiter to measure the cosmic radiation dose inside the Mir space station. One of the experiment's objectives was to determine the dose fraction on Mir due to the South Atlantic Anomaly (SAA) on an orbit inclined at 51.6 deg. and at an altitude of about 400 km. Using an hourly measuring period for 170 h in automatic mode, dose components both of galactic (independent of SAA) and SAA origin were determined. It was found that the maximum dose due to crossing the SAA was equal to 55 μGy. Averaging all the measurements it was calculated that the mean dose rate inside the Mir was 12-14 μGy.h -1 , and that half of this value was caused by the SAA. (author)

  19. Quality Assurance in Individual Monitoring: 10 Years of Performance Monitoring of the TLD Based TNO Individual Monitoring Service (invited paper)

    Energy Technology Data Exchange (ETDEWEB)

    Dijk, J.W.E. van

    1998-07-01

    The QA subscription forms the nucleus of the Quality Assurance (QA) programme of the TLD-based Individual Monitoring Service of TNO-CSD. This QA subscription is the subscription of a dummy customer to the service. As this customer is treated exactly like a normal customer, all aspects of the service are monitored by the QA subscription. An overview is given of 10 years of monitoring the performance of the service. Various improvements over the past decade have resulted in a standard deviation in a low dose measurement of 0.01 mSv and a relative standard deviation at higher doses of 5%. These figures represent the performance under routine circumstances and thus include variations due to variations in the natural background from place to place and, for example, due to transport. (author)

  20. On the effect of updated MCNP photon cross section data on the simulated response of the HPA TLD.

    Science.gov (United States)

    Eakins, Jonathan

    2009-02-01

    The relative response of the new Health Protection Agency thermoluminescence dosimeter (TLD) has been calculated for Narrow Series X-ray distribution and (137)Cs photon sources using the Monte Carlo code MCNP5, and the results compared with those obtained during its design stage using the predecessor code, MCNP4c2. The results agreed at intermediate energies (approximately 0.1 MeV to (137)Cs), but differed at low energies (<0.1 MeV) by up to approximately 10%. This disparity has been ascribed to differences in the default photon interaction data used by the two codes, and derives ultimately from the effect on absorbed dose of the recent updates to the photoelectric cross sections. The sources of these data have been reviewed.

  1. Beta response of CaSO4:Dy based TLD badge and its angular dependence studies for personnel monitoring applications

    International Nuclear Information System (INIS)

    Kumar, Munish; Rakesh, R.B.; Sneha, C.; Ratna, P.; Bakshi, A.K.; Datta, D.

    2016-01-01

    In India, shallow/skin doses received by radiation workers from beta particles are measured using CaSO 4 :Dy based Teflon embedded TLD badge. The beta particles having maximum energy E max > 0.6 MeV - ≥ 3.54 MeV are monitored. The ratio of the response of discs under open and plastic regions (D Open/ D Perspex ) is used to estimate the energy of the beta source and to apply response correction factor. This is required as the disc dosimeters are thick and exhibit energy dependent response. Due to lack of comprehensive information regarding disc ratios and associated beta multiplication/response correction factors, present study was performed

  2. The use of TLD-700H dosemeters in the assessment of external doses at the former Semipalatinsk nuclear test site.

    Science.gov (United States)

    Hill, P; Dederichs, H; Pillath, J; Schlecht, W; Hille, R; Artemev, O; Ptitskaya, L; Akhmetov, M

    2002-01-01

    The joint projects performed since 1995 by the Jülich Research Centre in co-operation with the Kazakh National Nuclear Centre in the area of the former nuclear test site near Semipalatinsk, in eastern Kazakhstan, have assessed the current dose rate of the population at and around the test site, as well as determining retrospectively the dose rate of persons affected by the atmospheric tests. Measurements of the population by personal dosemeters depend on reliably wearing these dosemeters over prolonged periods of time, and of a sufficient dosemeter return. In the past, such measurements have been particularly successful whenever short wearing times were possible. This requires high sensitivity of the dosemeters. The suitability of the highly sensitive TLD material of the BICRON TLD 700H type for such personal dosimetry measurements was investigated. It was tested in practical field application at the Semipalatinsk nuclear test site in September 2000. Initial results are available from individual doses received by a group of geologists and a group of herdsmen at the test site. For the first time, the individual dose was measured directly in these population groups. Detection limits below 1 microSv permit informative measurements for wearing times of less than two weeks. Most individual doses did not arise significantly out of local fluctuations of natural background. A conservative assessment from the aspect of practical health physics yielded a mean personal dose of 0.55 microSv per day for the herdsmen, whereas the geologists received a mean personal dose of 0.45 microSv per day. For an annual exposure period of typically, about three months, the radiation dose received by the persons investigated, in addition to the natural radiation exposure, is thus well below the international limit value of 1 mSv x a(-1) for the population dose.

  3. Measure of the attenuation curve of a beam of X-rays with TLD-100 dosimeters of LiF

    International Nuclear Information System (INIS)

    Bonzi, E. V.; Mainardi, R. T.; Germanier, A.; Delgado, V.

    2011-10-01

    The attenuation curve of a beam of X-rays represents the beam intensity in function of the attenuator thickness interposed between the source and the detector. To know with the major possible precision the attenuation curve is indispensable in procedures of spectral reconstruction. Their periodic measuring also offers valuable information on the correct operation of a tube of X-rays, diagnostic or therapy, when not have a specific detector for that activity. In this work was measured the attenuation curve of a tube of X-rays operated to 50 kV and 0.5 ma, using existent elements in any diagnostic or therapy laboratory with radiations. In the measures commercial aluminum foil was used, bent until 24 times and thermoluminescent dosimeters TLD 100 - LiF. Also, for comparison, was measured this attenuation curve with an ionization chamber brand Capintec model 192. Was determined by X-rays fluorescence the composition of the aluminium foil, since the present elements in the alloy can to affect the form of the attenuation curve. It is interesting to observe that these elements are in very low proportion (ppm) that they do not alter the attenuation capacity of the pure aluminium. Finally in a precision balance we weigh a big piece (30 cm x 100 cm) of aluminium foil and we obtained the thickness in g/c m2. It is possible to obtain attenuation curves of a beam of X-rays, with a high precision procedure and reproducibility. The use of TLD-100 dosimeters of LiF or similar makes that this activity was also quick and simple. (Author)

  4. Relative thermoluminescent efficiencies proton/gamma and helium/gamma of peaks of high temperature in TLD-100 dosemeters

    International Nuclear Information System (INIS)

    Flores M, E.

    2007-01-01

    The increase of the applications of ion beams in radiotherapy treatments has generated interest in the study of the thermoluminescent materials (TL) that allow to determine the applied doses. A way to quantify the TL response from these materials to ions is by means of the relative thermoluminescent efficiency. In the group of Thermoluminescent dosimetry of the Institute of Physics of the UNAM (IFUNAM) the thermoluminescent response of the TLD-100 dosemeters has been studied, which present a glow curve characteristic with several peaks that correspond to traps and luminescent centers in the material. The stable peaks know each other as 4, 5, 6a, 6b, 7, 8, 9 and 10. The efficiencies should be measured using the response so much to the radiation of interest (in this case protons and helium ions) as the response to gamma radiation. In previous works with ions of low energy taken place in the Pelletron accelerator of the IFUNAM was only measured the TL efficiency for the peak 5 and the total signal. It had not been possible to measure the efficiency of the peaks of high temperature (6a-10) because, for the gamma radiation, the peaks of high temperature show very small signals; however, recently Massillon carries out measures of efficiency TL of peaks of high temperature for ions of intermediate energy using a protocol special of reading and of deconvolution that allows to measure the signals coming from the peaks of high temperature. In this work is implemented this same protocol to complete the study of TL efficiencies at low energy of protons and helium and to determine if the values of efficiency depend on the used reading protocol. For it is reported it measures of the relative efficiency of the peaks of high temperature from the TLD-100 exposed to protons of 1.5 MeV and nuclei of helium of 3 and 7.5 MeV. (Author)

  5. Thermoluminescent response of dosemeters TLD-100 exposed to distinct baker protocols, irradiation and reading; Respuesta termoluminiscente de dosimetros TLD-100 sujetos a distintos protocolos de horneado, irradiacion y lectura

    Energy Technology Data Exchange (ETDEWEB)

    Estrada E, D

    2002-07-01

    The interest that motivated the realization of this work is the opposing discrepancy among the values of the efficiency thermoluminescent of heavy charged particles (PCP) regarding gamma radiation ({eta}{sub PCP}, {gamma}) reported in different works and gathered recently for Horowitz (Ho 01). The measures of relative thermoluminescent efficiency have importance in relation to the dosimetry associated to medical therapy with heavy charged particle. The measurement of {eta}{sub PCP}, {gamma} depends of multiple experimental factors. To understand this dependence it was quantified the effect of using different procedures experimental in the estimate of the relative thermoluminescent efficiency of dosemeters TLD-100 (LiF: Ti; Mg) for protons of 3 MeV regarding gamma rays of {sup 60}Co ({eta}{sub PCP}, {gamma}), varying the lot, the presentation, the one baked and the team reader. When was used the same global procedure values they were obtained for ({eta}{sub PCP}, {gamma}) inside the interval [0.30, 0.58] for the peak 5 and [0.35, 0.76] for the total thermoluminescent signal (Tl). At the use different equipment, baked and lot are obtained maximum differences of 30%, 12% and 6% respectively in the values of ({eta}{sub PCP}, {gamma}) for the peak 5, and 25%, 28% and 7% for the total Tl signal. The changes more significant of 36% and 44% for peak 5 and total signal respectively are obtained when changing the presentation of the dosemeter. As a complementary investigation it was studied the distribution of the Tl signal of each peak in the deconvolution of the curve of brightness with regard to the total signal in exposed dosemeters to high fluence of protons (1x10{sup 10} p/cm{sup 2}) varying the experimental protocol. It was found that the distribution of the Tl signal has a difference of the order of 5% when changing the used reading team. It was observed that the contribution of the peak 5 regarding the total signal are preserved when changing baked and that it

  6. 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

  7. Comparative study of thermoluminescent properties of LiF: Mg, Cu, P, LiF: Mg, Ti and TLD-100 irradiated with X-rays

    International Nuclear Information System (INIS)

    Azorin, J.; Rivera, T.; Gonzalez, P.; Ortega, X.; Ginjaume, M.

    2000-01-01

    The thermoluminescent properties (Tl) of LiF: Mg, Cu, P, and LiF: Mg, Ti, were investigated both developed in Mexico and comparing them with the properties of TLD-100 when they are exposure to X-rays. The Tl curve of LiF: Mg, Cu, P exhibited two peaks at 200 and 300 Centigrade. Its response Tl in function of dose resulted linear in the interval of 0.5 Gy until 5 Gy and its sensitivity to X-ray was around 25 times greater that of the TLD-100. Also it was measured the Tl response of the three materials in function of photon energy. The results showed that LiF: Mg, Cu, P has potential to be used as X-ray dosemeter. (Author)

  8. Measurement of dose to skin using TLD of several radiodiagnostic studies in San Jose, Costa Rica; Medicion de dosis a piel utilizando TLD de varios estudios radiodiagnosticos en San Jose, Costa Rica

    Energy Technology Data Exchange (ETDEWEB)

    Mora, P. [Laboratorio de Fisica Nuclear Aplicada, Escuela de Fisica, Universidad de Costa Rica, San Jose (Costa Rica)

    1998-12-31

    It is quantified the radiation doses on skin for several radiodiagnostic studies in patients of the Calderon Guardia Hospital in San Jose, Costa Rica at the period October 1997-September 1998 using thermoluminescent dosemeters TLD 100. The crystals receive the decoction standard procedures and they are arranged at the middle of the irradiation field. For a total of 973 radiodiagnostic studies it was found that the dose on skin in mGy are: 2.09 for thorax AP/AP, 5.33 for thorax LAT, 5.35 for skull AP/PA, 2.98 for skull LAT, 10.74 for abdomen, hips and pelvis, 6.20 for spines AP, 9.35 for spines LAT, 11.48 for lumbar columns AP, 29.99 for lumbar columns LAT and 6.87 for intravenous skin diagrams (first plate ap). It is produced thus the first reference bank for the national hospitals, which is compared with the orientation levels of doses for IAEA. Recommendations to diminish the collective doses through quality control programs are discussed, taking as goal to have got radiographs of excellent diagnostic quality, but with the less possible doses. (Author)

  9. Dosimetric intercomparison in Cobalt 60 unities using TLD-100 crystals and CaSO{sub 4}: Dy + Ptfe; Intercomparacion dosimetrica en unidades de cobalto 60 usando cristales de TLD-100 y CaSO{sub 4}: Dy + PTFE

    Energy Technology Data Exchange (ETDEWEB)

    Gaona, E. [Universidad Autonoma Metropolitana Xochimilco, Mexico D.F. (Mexico); Azorin N, J. [Universidad Autonoma Metropolitana Iztapalapa, Mexico D.F. (Mexico); Perez P, M.A. [Instituto Nacional de Cancerologia, Mexico D.F. (Mexico); Castillo H, M. [Centro Medico Nacional 20 de Noviembre, ISSSTE, Mexico D.F. (Mexico); Flores F, F. [Unidad de Oncologia, Centro Medico Nacional, IMSS, Mexico D.F. (Mexico); Guzman R, L.V. [Unidad de Oncologia, Hospital General de Mexico, Mexico D.F. (Mexico)

    1999-07-01

    The purpose of this work is to design and construct a phantom in basis of thermoplastic polymer of methyl methacrylate that is reutilizable and which allows to do an analysis of the absorbed doses in thermoluminescent crystals (Tl) exposed to cobalt 60 to establish the dosimetric intercomparison in cobalt units which allows to do the follow-up of the Quality assurance programs, standardization of calibration procedures, dosimetry and TLD post intercomparison in radiotherapy. This work allows also prove new thermoluminescent materials of national manufacture developed by Juan Azorin and collaborators as the CaSO{sub 4}: Dy + Ptfe. This is a first study which is realized in Mexico with the system crystal-phantom for aims to intercomparison in cobalt 60 units. In this work participate eight unities of cobalt 60 of different trades belonging at four radiotherapy centers. The results of the dose intercomparison of the eight unities of cobalt 60 were in the range 0.95-1.13, taking in account that the values between 0.95 and 1.05 were considered acceptable in terms of the requirements by the standing legislation. (Author)

  10. TLD-300 detectors for separate measurement of total and gamma absorbed dose distributions of single, multiple, and moving-field neutron treatments

    International Nuclear Information System (INIS)

    Rassow, J.

    1984-01-01

    Fast neutron therapy requirements, because of the poor depth dose characteristic of present therapeutical sources, are at least as complex in treatment plans as photon therapy. The physical part of the treatment planning is very important; however, it is much more complicated than for photons or electrons owing to the need for: Separation of total and gamma absorbed dose distributions (Dsub(T) and Dsub(G)); and more stringent tissue-equivalence conditions of phantoms than in photon therapy. Therefore, methods of clinical dosimetry for the separate determination of total and gamma absorbed dose distributions in irregularly shaped (inhomogeneous) phantoms are needed. A method using TLD-300 (CaF 2 :Tm) detectors is described, which is able to give an approximate solution of the above-mentioned dosimetric requirements. The two independent doses, Dsub(T) and Dsub(G), can be calculated by an on-line computer analysis of the digitalized glow curve of TLD-300 detectors, irradiated with d(14)+Be neutrons of the cyclotron isocentric neutron therapy facility CIRCE in Essen. Results are presented for depth and lateral absorbed dose distributions (Dsub(T) and Dsub(G)) for fixed neutron beams of different field sizes compared with measurements by standard procedures (TE-TE ionization chamber, GM counter) in an A-150 phantom. The TLD-300 results for multiple and moving-field treatments (with and without wedge filters) in a patient simulating irregularly shaped (inhomogeneous) phantoms, are shown together with computer calculations of these dose distributions. The probable causes for some systematic deviations are discussed, which lead to open problems for further investigations owing to features of the detector material and the evaluation method, but mainly to differences in the composition of phantom materials used for the calculations (standard dose distributions) and TLD-300 measurements. (author)

  11. Dosimetric analysis using glasses TLD-100 Lif; Mg; TI for the optimization of the quality control programs in radio surgery stereo tactic

    International Nuclear Information System (INIS)

    Maldonado, J. C; Plazas, M. C.; Dussan, R.; Conrado, Z.; Pena, G.; Jimenez, E.; Hakim, F.; Bermudez, S.

    2001-01-01

    The conditions of Stereo Tactic Radio Surgery treatments are simulated by means of the use of thermo luminescent glasses TLD-100 LiF; Mg; Ti placed in mannequins, to demonstrate that the doses received by the patients, either in the fractioned or in the mono fractioned techniques, are over the 500cGy, making urgent the use of a reliable dosimetric method [es

  12. Personal and environmental dosimetric measurements using TLD method in Cardiac Catheterization Laboratory (CathLab) at the Rzeszow's Regional Hospital No 2, Poland

    International Nuclear Information System (INIS)

    Kisielewicz, K.; Truszkiewicz, A.; Wach, S.; Budzanowski, M.

    2007-01-01

    Complete test of publication follows. One of the basic problem in CathLab is the monitoring of ionizing radiation, calculations of doses for workers and finally to build a system to prevent workers from X-ray radiation. To measure doses from X-rays a passive method with thermoluminescent dosemeters (TLD) were applied. Experimental part was based on creating 3D grid of Tl environmental dosemeters with 2 high sensitive TL detectors based on MCP-N (LiF:Mg,Cu,P). Dosemeters were placed evenly (as far as staff's work conditions allowed such positioning) in operating room and a control room. Grid of about 100 dosemeters was designed to measure X-ray dose distribution present during interventional cardiology procedures. That part of the project was especially important for hospital's employee, because it has brought an information about most radiative dangerous areas of each room. Patient dosimetry measurements have been also made using TLD method just during the interventional cardiology procedures. Every patient got a few dosemeters dor different parts of body. Experimental part consists of measurements of absorbed dose equivalent, mean dose rate of absorbed dose equivalent, and mean dose of effective dose per each body part. That last measurements were accomplished by placing TLD's near patient's head, chest and gonads. Personal dosimetry for employees, has been made using TLD's during hemodynamics procedures. Every employee (medical doctors, nurses, technicians and charwoman) has received few dosemeters also based on high sensitive MCP-N detectors. The main dosimetry was done for whole body covered by led gown and additionally for unprotected parts: (hands, arm, eyes and protected by gown: chest, gonads). For individual dosimetry Hp(10) in mSv was calculated, while using environmental dosemeters KERMA in air in mGy. This work will present results obtained from ca. 100 environmental placed in CathLab room. Additionally personal doses for whole body and for parts of

  13. Operational comparison of TLD albedo dosemeters and etched-track detectors in the PuO2-UO2 mixed oxide fuel fabrication facilities

    International Nuclear Information System (INIS)

    Tsujimura, N.; Takada, C.; Yoshida, T.; Momose, T.

    2005-01-01

    Full text: The authors carried out an operational study that compared the use of TLD albedo dosemeters with etched-track detector in plutonium environments of Japan Nuclear Cycle Development Institute, Tokai Works. A selected group of workers engaged in the fabrication process of MOX (PuO 2 -UO 2 mixed oxide) fuel wore both TLD albedo dosemeters and etched-track detectors over a period from 1991 to 1993. The TLD albedo dosemeter is the Panasonic model UD-809P and the etched-track detector is the NEUTRAK (polyallyl diglycol carbonate + 1mm-t polyethylene radiator) commercially available from Nagase-Landauer Ltd. Both dosemeters were issued and read monthly. It was found that the TL readings were generally proportional to the counted etch-pits, and thus the dose equivalent results obtained from TLD albedo dosemeter agreed with those from etched-track detector within a factor of 1.5. This result indicates that, in the workplaces of the MOX plants, the neutron spectrum remained almost constant in terms of time and space, and the appropriate range of field-specific correction with spectrum variations could be small in albedo dosimetry. In addition, the calibrations of both dosemeters in the workplaces and in a bare and moderated 252 Cf calibration field were performed for quantitative validation for the results from the operational comparison. In the former experiments, locations were selected that were representative of typical neutron measurements according to the prior neutron spectra measurements with the multi-sphere spectrometer. In the latter experiments, the workplace environments were simulated by using a 252 Cf source surrounded with cylindrical steel/PMMA moderators. From both experiments, the relationship between TL readings and counted etch-pits with neutron spectrum variation was determined. As expected, the relationship obtained from the simulated workplace field calibration reproduced that from the operational comparison. (author)

  14. Investigation of a new LiF TLD individual dosimeter for measuring personal dose equivalent Hp(d) on different phantoms

    International Nuclear Information System (INIS)

    Jin, H.; Duftschmid, K.E.; Strachotinsky, C.

    1992-09-01

    The paper describes a new LiF TLD dosimeter designed for measuring personal dose equivalent, H p (d). Its energy and angular response have been studied in detail on a PMMA slab phantom using the conversion factors for TE slab phantom. According to the results obtained with four types of different conversion coefficients and phantoms, i.e. a PMMA slab, Water slab, ICRU sphere and Alderson Rando phantom, the conversion coefficients for the TE slab phantom are suitable for the calibration of TLD individual dosimeters on PMMA slab phantom. In the energy range 17 keV to 1250 KeV the energy response for H p (10) and H p (0.07) is energy independent within -20% to 8.4% for frontal irradiation. For angles within ±60 deg the new TLD dosimeters indicate H p (10) within 0 to 22.5% and H p (0.07) within -11.1% to 1.3%, respectively. (authors)

  15. Monte Carlo determination of the infinite matrix dose rate correction factors for 250 μm quartz and TLD500 chip

    International Nuclear Information System (INIS)

    Baly, L.; Martín, G.; Quesada, I.; Padilla, F.; Arteche, R.

    2015-01-01

    A new approach based on the Monte Carlo simulation is used to calculate the infinite matrix dose rate correction factors of gamma, beta and internal conversion radiations for 250 μm diameter grains of quartz and TLD500 chips. Here, the dependence of the correction factor on the radiation energy is initially calculated for each type of emitted particle and with this result the correction factors for the 232 Th and 238 U series and 40 K are determined. This analysis is made for dry soil and also for different levels of water content in it. The obtained beta correction factors for quartz are in good agreement with those previously reported. For the TLD500 chip certain differences with previously reported data are found. The analysis of the gamma water correction factor for quartz based on Zimmerman equation shows the correspondence with the similar correction factor for electrons. In the case of TLD500 chip a gamma water correction factor value of 1.0 was found. - Highlights: • A new approach based on Monte Carlo simulation is used to compute infinite matrix dose rate correction factors. • Infinite matrix models with real dimensions were analyzed within 3% uncertainties. • The dependence of grain size attenuation on particle energy is determined. • The same dependence for water correction factors is also analyzed

  16. Dosimetric intercomparison in Cobalt 60 unities using TLD-100 crystals and CaSO4: Dy + Ptfe

    International Nuclear Information System (INIS)

    Gaona, E.; Azorin N, J.; Perez P, M.A.; Castillo H, M.; Flores F, F.; Guzman R, L.V.

    1999-01-01

    The purpose of this work is to design and construct a phantom in basis of thermoplastic polymer of methyl methacrylate that is reutilizable and which allows to do an analysis of the absorbed doses in thermoluminescent crystals (Tl) exposed to cobalt 60 to establish the dosimetric intercomparison in cobalt units which allows to do the follow-up of the Quality assurance programs, standardization of calibration procedures, dosimetry and TLD post intercomparison in radiotherapy. This work allows also prove new thermoluminescent materials of national manufacture developed by Juan Azorin and collaborators as the CaSO 4 : Dy + Ptfe. This is a first study which is realized in Mexico with the system crystal-phantom for aims to intercomparison in cobalt 60 units. In this work participate eight unities of cobalt 60 of different trades belonging at four radiotherapy centers. The results of the dose intercomparison of the eight unities of cobalt 60 were in the range 0.95-1.13, taking in account that the values between 0.95 and 1.05 were considered acceptable in terms of the requirements by the standing legislation. (Author)

  17. Study of crystal structure and of dynamic behaviour in the various phases of TlD2PO4

    International Nuclear Information System (INIS)

    Rios, S.

    1997-01-01

    TlH2PO4 (TDP) and its deuterated form TlD2PO4 (DTDP) belong to the family of ferroelectric materials of KH2PO4 (KDP). The compounds of this family, on deuteration, show a large isotopic effect in their ferroelectric transition temperatures. This work begins with a review of theoretical models which allowed a better understanding of the antiferroelectric transition. The crystal structures of TDP and DTDP have been studied at different temperatures, using single-crystal neutron diffraction and the results show that the phase diagrams for both compounds have very different characteristics. The dynamics of antiferroelectric transition of DTDP has been investigated by means of neutron inelastic scattering. Supported by these experimental results we propose a mechanism to explain the different phase sequences in these compounds. In the last part of this work a more qualitative study suggests that the effect of deuteration could be seen as a pressure effect. This result has to be confirmed by using a more appropriate means of investigation than neutron scattering. (A.C.)

  18. Effects of annealing on the sensitivity of LiF TLD-100 after repeated use for low dose measurements

    International Nuclear Information System (INIS)

    Ogunleye, O.T.; Richmond, R.G.

    1987-01-01

    The changes in sensitivity of LiF TLD-100 extruded ribbons subjected to repeated use up to 100 times were investigated. Three different annealing regimes were compared. The dosemeters were annealed at 400 0 C followed by (i) a slow or (ii) fast cooling to room temperature or (iii) utilising a 20 s readout process in the reader without a high temperature annealing at 400 0 C. Each of the three groups consisted of two sets of 20 chips each, with one set receiving 500 μ Gy of 90 Sr beta radiation and the other unirradiated. Sensitivity evaluations were performed every five cycles through the first 50 cycles, and on each tenth cycle thereafter. On the average, the fast cooled group maintained their integrity best, while a maximum variation in sensitivity of about 15% was observed in the irradiated set of the slowly cooled group. A permanent increase in sensitivity of at least 10% was observed for the set of dosemeters receiving radiation without annealing. Glow curve analyses showed an increase in the ratio of peaks 4 and 5 with repeated use of this group. (author)

  19. Extra Dose Due to Extravehicular Activity During the NASA4 Mission, Measured by an On-Board TLD System

    Energy Technology Data Exchange (ETDEWEB)

    Deme, S.; Apathy, I.; Hejja, I.; Lang, E.; Feher, I. [Budapest (Hungary)

    1999-07-01

    A microprocessor-controlled on-board TLD system, 'Pille'96', was used during the NASA4 (1997) mission to monitor the cosmic radiation dose inside the Mir Space Station and to measure the extra dose to two astronauts in the course of their extravehicular activity (EVA). For the EVA dose measurements, CaSO{sub 4}:Dy bulb dosemeters were located in specially designed pockets of the ORLAN spacesuits. During an EVA lasting 6 h, the dose ratio inside and outside Mir was measured. During the EVA, Mir crossed the South Atlantic Anomaly three times. Taking into account the influence of these three crossings the mean EVA/internal dose rate ratio was 3.2. Internal dose mapping using CaSO{sub 4}:Dy dosemeters gave mean dose rates ranging from 9.3 to 18.3 {mu}Gy.h{sup -1} at locations where the shielding effect was not the same. Evaluation results of the high temperature region of LiF dosemeters are given to estimate the mean LET. (author)

  20. Analysis of QUADOS problem on TLD-ALBEDO personal dosemeter responses using discrete ordinates and Monte Carlo methods

    International Nuclear Information System (INIS)

    Kodeli, I.; Tanner, R.

    2005-01-01

    In the scope of QUADOS, a Concerted Action of the European Commission, eight calculational problems were prepared in order to evaluate the use of computational codes for dosimetry in radiation protection and medical physics, and to disseminate 'good practice' throughout the radiation dosimetry community. This paper focuses on the analysis of the P4 problem on the 'TLD-albedo dosemeter: neutron and/or photon response of a four-element TL-dosemeter mounted on a standard ISO slab phantom'. Altogether 17 solutions were received from the participants, 14 of those transported neutrons and 15 photons. Most participants (16 out of 17) used Monte Carlo methods. These calculations are time-consuming, requiring several days of CPU time to perform the whole set of calculations and achieve good statistical precision. The possibility of using deterministic discrete ordinates codes as an alternative to Monte Carlo was therefore investigated and is presented here. In particular the capacity of the adjoint mode calculations is shown. (authors)

  1. Application of the Cavity theory in the calibration of the powder TLD-100 for energies of 60 Co, 137 Cs, 192 Ir and RX 50, 250 k Vp

    International Nuclear Information System (INIS)

    Loaiza C, S.P.; Alvarez R, J.T.

    2006-01-01

    A powder lot TLD-100 (LiF:Mg,Ti) in absorbed dose terms in water D w for the following radiation sources: 60 Co, 137 Cs and RX 50 and 250 k Vp is calibrated; to continuation is made a lineal interpolation of the TLD response in function of the effective energy of the sources to calibrate a source of 192 Ir. The calibration of those fields in D w are carried out with aid of the Bragg-Gray cavity theory, the one which finds implicit in the following protocols: IAEA-TRS 398 for the 60 Co and the AAPM TG61 for X Rays of 50 and 250 k Vp. Additionally the AAPM protocol TG43 to determine the D w in function of the kerma intensity S k in the case of the 137 Cs is used. The calibration curves for the response of the TLD-100 R TLD vs D w , corresponding to each one of the sources already mentioned are constructed. The R TLD vs D w by least heavy square by means of a second order polynomial that corrects the supralineality of the response is adjusted. The curves are validated by lack of LOF adjustment and by the Anderson Darling normality test. Later the factors of sensitivity (F s ) for the sources of 192 Ir: Micro Selectron and Vari Source are interpolated, used respectively in the A and B hospitals for treatments of brachytherapy of high dose rate (HDR), the expanded uncertainties associated to the D w and F s are also determined. Finally, an acrylic phantom and a couple of capsules are already sent to the hospitals mentioned, to verify a nominal D w of 2 Gy, in a case an underestimate in 5.5% in the imparted D w and in other an overestimation in a range of -1.5 to -8.0% was obtained. The obtained results in this work establish the bases for the development of a national dosimetric quality control program for brachytherapy of HDR with sources of 192 Ir. (Author)

  2. Thin films

    International Nuclear Information System (INIS)

    Strongin, M.; Miller, D.L.

    1976-01-01

    This article reviews the phenomena that occur in films from the point of view of a solid state physicist. Films form the basis for many established and developing technologies. Metal layers have always been important for optical coatings and as protective coatings. In the most sophisticated cases, films and their interaction on silicon surfaces form the basis of modern electronic technology. Films of silicon, GaAs and composites of these materials promise to lead to practical photovoltaic devices

  3. Neutron-photon mixed field dosimetry by TLD-700 glow curve analysis and its implementation in dose monitoring for Boron Neutron Capture Therapy (BNCT) treatments

    Energy Technology Data Exchange (ETDEWEB)

    Boggio, E. F.; Longhino, J. M. [Centro Atomico Bariloche, Departamento de Fisica de Reactores y Radiaciones / CNEA, Av. E. Bustillo Km 9.5, R8402AGP San Carlos de Bariloche (Argentina); Andres, P. A., E-mail: efboggio@cab.cnea.gov.ar [Centro Atomico Bariloche, Division Proteccion Radiologica / CNEA, Av. E. Bustillo Km 9.5, R8402AGP San Carlos de Bariloche (Argentina)

    2015-10-15

    BNCT is a cancerous cells selective, non-conventional radiotherapy modality to treat malignant tumors such as glioblastoma, melanoma and recurrent head and neck cancer. It consists of a two-step procedure: first, the patient is injected with a tumor localizing drug containing a non-radioactive isotope (Boron-10) with high slow neutron capture cross-section. In a second step, the patient is irradiated with neutrons, which are absorbed by the Boron-10 agent with the subsequently nuclear reaction B- 10(n,a)Li-7, thereby resulting in dose at cellular level due to the high-Let particles. The neutron fields suitable for BNCT are characterized by high neutron fluxes and low gamma dose. Determination of each component is not an easy task, especially when the volume of measurement is quite small or inaccessible for a miniature ionization chamber, for example. A method of measuring the photon and slow neutron dose(mainly by N-14 and B-10) from the glow curve (GC) analysis of a single {sup 7}LiF thermoluminescence detector is evaluated. This method was suggested by the group headed by Dr. Grazia Gambarini. The dosemeters used were TLD-600 ({sup 6}LiF:Mg,Ti with 95.6% {sup 6}Li) and TLD-700 ({sup 7}LiF:Mg,Ti with 99.9% {sup 7}LiF) from Harshaw. Photon dose measurement using the GC analysis method with TLD-700 in mixed fields requires the relation of the two main peaks of a TLD-600 GC shape obtained from an exposition to the same neutron field, and a photon calibrated GC with TLD-700. The requirements for slow neutron dose measurements are similar. In order to properly apply the GC analysis method at the Ra-6 Research Reactor BNCT facility, measurements were carried out in a standard water phantom, fully characterized on the BNCT beam by conventional techniques (activation detectors and paired ionization chambers technique). Next, the method was implemented in whole body dose monitoring of a patient undergoing a BNCT treatment, using a Bo MAb (Bottle Manikin Absorption) phantom

  4. Nuclear films

    International Nuclear Information System (INIS)

    Malone, Peter.

    1985-01-01

    This booklet is a resource for the study of feature films that highlight the theme of nuclear war. It provides basic credits and brief indication of the theme, treatment, quality and particular notable aspects; and a series of questions raised by the film. Seventy feature films and thirty documentaries are examined

  5. Development of measurement method using TLD for workers occupation personally exposed to 125I seed source in the implant

    International Nuclear Information System (INIS)

    Luo Suming; He Zhijian; Yuan Jilong; Yue Baorong; Wei Kedao

    2011-01-01

    Objective: To explore the method for measuring and calculating both absorbed dose and effective dose received in organ and tissues of occupational workers by using TLDs for the implantation of 125 I seed sources. Methods The experiments with 60 Co γ-rays were carried out for the stability. A group of TLD chips was exposed to 125 I seed sources to establish standard dose curve for air kerma. During the 125 I seed implantation, the TLD chips were pasted to 13 locations like thyroid inside and outside the lead aprons worn by occupational workers to measure average absorbed dose and calculate the absorbed doses and effective to organs and tissues. Results: For 3 cases of prostate cancers with implantation of 125 I seeds, the worker's organs and tissues received the absorbed dose 0.02 -3.80 μ Gy and effective dose 0.06- 1.81 μSv outside lead aprons and the highest absorbed dose 2.35 μ Gy and effective 0.02 μSv inside lead aprons, respectively, with more than 65.9% of rays shielded. For 3 cases of brain cancers with implantation of 125 I seeds, the workers received the absorbed dose 0.23 - 11.31 μGy and effective dose 0.88-4.07 μSv outside lead aprons and the highest absorbed dose 2.22 μ Gy and effective dose 0.09 μSv inside lead aprons, respectively, with more than 54.5% of rays shielded. For 3 cases of lung cancers with implantation of 125 I seeds, the workers received the absorbed dose 0.03 - 14.78 μGy and effective dose 0.35 -7.59 μSv outside lead aprons and the highest absorbed dose 4.09 μGy and effective 0.22 μSv inside lead aprons, respectively, with more than 58.4% of rays shielded. For 2 cases of mediastinum cancers with implantation of 125 Iseeds, the workers received the absorbed dose 0.06 - 74.91 μGy and effective dose 0.83-17.96 μSv outside lead aprons and the highest absorbed dose 10.29 μGy and effective 0.5 μSv inside lead aprons, respectively, with more than 85% of rays shielded. For one case of ovary cancer with implantation of 125

  6. Effect of improved TLD dosimetry on the determination of dose rate constants for 125I and 103Pd brachytherapy seeds

    International Nuclear Information System (INIS)

    Rodriguez, M.; Rogers, D. W. O.

    2014-01-01

    Purpose: To more accurately account for the relative intrinsic energy dependence and relative absorbed-dose energy dependence of TLDs when used to measure dose rate constants (DRCs) for 125 I and 103 Pd brachytherapy seeds, to thereby establish revised “measured values” for all seeds and compare the revised values with Monte Carlo and consensus values. Methods: The relative absorbed-dose energy dependence, f rel , for TLDs and the phantom correction, P phant , are calculated for 125 I and 103 Pd seeds using the EGSnrc BrachyDose and DOSXYZnrc codes. The original energy dependence and phantom corrections applied to DRC measurements are replaced by calculated (f rel ) −1 and P phant values for 24 different seed models. By comparing the modified measured DRCs to the MC values, an appropriate relative intrinsic energy dependence, k bq rel , is determined. The new P phant values and relative absorbed-dose sensitivities, S AD rel , calculated as the product of (f rel ) −1 and (k bq rel ) −1 , are used to individually revise the measured DRCs for comparison with Monte Carlo calculated values and TG-43U1 or TG-43U1S1 consensus values. Results: In general, f rel is sensitive to the energy spectra and models of the brachytherapy seeds. Values may vary up to 8.4% among 125 I and 103 Pd seed models and common TLD shapes. P phant values depend primarily on the isotope used. Deduced (k bq rel ) −1 values are 1.074 ± 0.015 and 1.084 ± 0.026 for 125 I and 103 Pd seeds, respectively. For (1 mm) 3 chips, this implies an overall absorbed-dose sensitivity relative to 60 Co or 6 MV calibrations of 1.51 ± 1% and 1.47 ± 2% for 125 I and 103 Pd seeds, respectively, as opposed to the widely used value of 1.41. Values of P phant calculated here have much lower statistical uncertainties than literature values, but systematic uncertainties from density and composition uncertainties are significant. Using these revised values with the literature’s DRC measurements, the

  7. Characterization of {sup 6}LiF:Mg,Cu,P (TLD-600 H) estimate of E, b and s parameters

    Energy Technology Data Exchange (ETDEWEB)

    Andres, P. A., E-mail: andresp@cab.cnea.gov.ar [Centro Atomico Bariloche, Division Proteccion Radiologica / CNEA, Av. E. Bustillo Km 9.5, R8402AGP San Carlos de Bariloche (Argentina)

    2015-10-15

    LiF:Mg,Cu,P dosemeters are useful for low-dose measurements because of its high sensitivity compared to the LiF:Mg,Ti dosemeters. {sup 7}LiF:Mg,Cu,P have been used for environmental dosimetry in Bariloche Atomic Centre for almost a decade. Since {sup 6}LiF:Mg,Cu,P dosemeters were intended to be used for X ray diagnosis dosimetry in neonatology, they had to be characterized first. The main goal of measuring and analyzing Tl glow curves is the extraction of some parameters that can be used to describe the Tl process in the material. This job focused on the estimation of the activation energy E for the Tl traps, the frequency factor s and the order of kinetics b of the Tl process. Furthermore, the most appropriate time-temperature profile (Ttp) was determined as well as the annealing temperature and time, which resulted being 240 degrees C for 10 minutes. The Ttp used was 140 degrees C for 10 seconds, a heating rate of 20/s until 240 degrees C, remaining at this temperature for 20 seconds, and then an exponential cooling until 50 degrees C. After applying the whole glow-peak method for different orders of kinetic, and the Kitis equation assuming a first order kinetics, the values obtained were: E = (1.066 ± 0.025) eV, as a weighted average of both methods, and a frequency factor s = (3.57 ± 1.56) E-10 s{sup -1} again as a weighted average of both methods. In both cases a first order kinetics (b = 1) was assumed. The dosemeters were irradiated with a calibrated {sup 137}Cs source and read with a Harshaw TLD{sup TM} Model 3500 reader resulting in a minimum detectable dose of about 20 μGy. (Author)

  8. Gamma radiation induced sensitization and photo-transfer in Mg2SiO4:Tb TLD phosphor

    International Nuclear Information System (INIS)

    Lakshmanan, A.R.; Vohra, K.G.

    1979-01-01

    Mg 2 SiO 4 :Tb TLD phosphor was found to show enhanced TL sensitivity to both gamma and UV radiations after high pre-gamma exposures (>100 R) and a post-annealing treatment at 300 0 C for 1 h. Maximum sensitization factors of 2.8 and 55 were obtained at the pre-expsoure levels of 5.2x10 1 C/kg and 1.3x10 3 C/kg for gamma and UV test radiations respectively. The near constancy of the intensity of the residual TL (RTL) peak at 500 0 C for the sensitized sample with increasing test-gamma exposures has ruled out the re-trapping model proposed earlier for the gamma radiation induced sensitization in this phosphor. The Tsub(max) for the sensitized phosphor was found to occur at a higher temperature compared to that for the virgin phosphor. The dependence of sensitization on RTL was explained qualitatively on the basis of competition between sensitization traps (having higher energy than the dosimetry traps) and RTL traps while capturing the charge carriers generated during the test-gamma exposure. The sensitization observed in this phosphor to UV test radiation was found to be a consequence of the photo-transfer of charge carriers from deep (RTL) traps to the shallow (dosimetry) traps. The reduction in RTL peak (500 0 C) intensity of the sensitized sample with increasing test-UV exposure has demonstrated the photo-transfer mechanism in this phosphor. The TL response of the virgin Mg 2 SiO 4 :Tb phosphor was found to be supralinear to both gamma and UV radiations. The TL response of the sensitized phosphor was found to be linear to gamma radiation and sublinear to UV radiation. (Auth.)

  9. Assessment of the effectiveness of attenuation of leaded aprons through TLD dosimetry and Monte Carlo simulation method

    Energy Technology Data Exchange (ETDEWEB)

    Olaya D, H.; Diaz M, J. A.; Martinez O, S. A. [Universidad Pedagogica y Tecnologica de Colombia, Grupo de Fisica Nuclear Aplicada y Simulacion, 150003 Tunja, Boyaca (Colombia); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

    2016-10-15

    Were performed experimental setups using an X-ray equipment continuous emission Pantak DXT-3000 and three types of leaded aprons with thickness of 0.25, 0.5 and 0.75 mm coated with Mylar Fiber coated Mylar on its surface. Apron was located at a distance of 2.5 m with respect focus in order to cover a radiation field size of a meter in diameter. At the beam output were added aluminum filtration in order to reproduce qualities of narrow beams N-40 (E{sub efective} = 33 keV), N-80 (E{sub efective} = 65 keV) and N-100 (E{sub efective} = 83 keV) according to the ISO standard 4037 (1-3). Each lead apron were fixed 10 TLD dosimeters over its surface, 5 dosimeters before and 5 dosimeters after with respect to X-ray beam and were calibrated for Harshaw 4500 thermoluminescent reader system order to assess the attenuation of each apron. Were performed dosimeters readings and were calculated the attenuation coefficients for each effective energy of X-ray quality. In order to confirm the method of effective energy of ISO-4037 and evaluate effectiveness of lead aprons based on energy range for each medical practice was made a Monte Carlo simulation using code GEANT-4, calculating the fluence and absorbed dose in each one of the dosimeters Monte Carlo, then coefficients of linear attenuation were calculated and compared with the experimental data and reported by the National Institute of Standards and Technology (Nist). Finally, results are consistent between theoretical calculation and experimental measures. This work will serve to make assessments for other personalized leaded protections. (Author)

  10. Assessment of the effectiveness of attenuation of leaded aprons through TLD dosimetry and Monte Carlo simulation method

    International Nuclear Information System (INIS)

    Olaya D, H.; Diaz M, J. A.; Martinez O, S. A.; Vega C, H. R.

    2016-10-01

    Were performed experimental setups using an X-ray equipment continuous emission Pantak DXT-3000 and three types of leaded aprons with thickness of 0.25, 0.5 and 0.75 mm coated with Mylar Fiber coated Mylar on its surface. Apron was located at a distance of 2.5 m with respect focus in order to cover a radiation field size of a meter in diameter. At the beam output were added aluminum filtration in order to reproduce qualities of narrow beams N-40 (E_e_f_e_c_t_i_v_e = 33 keV), N-80 (E_e_f_e_c_t_i_v_e = 65 keV) and N-100 (E_e_f_e_c_t_i_v_e = 83 keV) according to the ISO standard 4037 (1-3). Each lead apron were fixed 10 TLD dosimeters over its surface, 5 dosimeters before and 5 dosimeters after with respect to X-ray beam and were calibrated for Harshaw 4500 thermoluminescent reader system order to assess the attenuation of each apron. Were performed dosimeters readings and were calculated the attenuation coefficients for each effective energy of X-ray quality. In order to confirm the method of effective energy of ISO-4037 and evaluate effectiveness of lead aprons based on energy range for each medical practice was made a Monte Carlo simulation using code GEANT-4, calculating the fluence and absorbed dose in each one of the dosimeters Monte Carlo, then coefficients of linear attenuation were calculated and compared with the experimental data and reported by the National Institute of Standards and Technology (Nist). Finally, results are consistent between theoretical calculation and experimental measures. This work will serve to make assessments for other personalized leaded protections. (Author)

  11. Formation of rod type structures of CaSO4: Ce,P,Dy TLD phosphor using different synthesis routes

    International Nuclear Information System (INIS)

    Atone, M.S.; Wani, J.A.; Dhoble, S.J.

    2011-01-01

    Effect of Ce and P co-activation in CaSO 4 : Dy, standard TLD phosphor prepared by different synthesis root techniques and it's structural morphology is reported first time in this paper. We have already reported the sensitization of luminescence in CaSO 4 : Dy with phosphorous (P) and cerium (Ce) ions separately via acid distillation route. In the current investigation, we have doped these impurities (Ce, P, Dy) simultaneously in CaSO 4 host lattice. We have employed a well known chemical precipitation method and modified acid distillation method and have attempted to analyse the surface morphology resulted from these two synthesis routes. Chemical precipitation usually takes place at room temperature and in this way allows the reaction to take place silently. In case of acid distillation method we have reduced the synthesis temperature to 493K which is considerably less than 653K employed in previously reported literature. In case of precipitation method particle shape seems to be spherical and particle size is around one micro range or in the neighbourhood of nanorange. However, in the case of modified acid distillation method particles have shaped in to rod like structures and particle size again falls in the micro range. The photoluminescence intensity of the phosphor prepared by chemical precipitation method is weak as compared to the phosphor prepared by modified acid distillation method. Both the phosphors prepared by different methods have shown characteristic transitions of dopants. The emission spectra of prepared phosphors at 309 nm and 329 nm of Ce 3+ ions overlap well with excitation of Dy 3+ ions. Thermoluminescence (TL) property of both phosphors is again good though certain variation is observed in case of phosphor prepared by modified acid distillation method which shows rod like structure of phosphor. This variation in TL may be attributed to change in surface morphology (formation of rod type structure of particles) of the phosphor. (author)

  12. SU-E-T-108: Development of a Novel Clinical Neutron Dose Monitor for Proton Therapy Based On Twin TLD500 Chips in a Small PE Moderator

    International Nuclear Information System (INIS)

    Hentschel, R; Mukherjee, B

    2014-01-01

    Purpose: In proton therapy, it could be desirable to measure out-of-field fast neutron doses at critical locations near and outside the patient body. Methods: The working principle of a novel clinical neutron dose monitor is verified by MCNPX simulation. The device is based on a small PE moderator of just 5.5cm side length for easy handling covered with a thermal neutron suppression layer. In the simulation, a polystyrene phantom is bombarded with a standard proton beam. The secondary thermal neutron flux produced inside the moderator by the impinging fast neutrons from the treatment volume is estimated by pairs of α-Al2O3:C (TLD500) chips which are evaluated offline after the treatment either by TL or OSL methods. The first chip is wrapped with 0.5mm natural Gadolinium foil converting the thermal neutrons to gammas via (n,γ) reaction. The second chip is wrapped with a dummy material. The chip centers have a distance of 2cm from each other. Results: The simulation shows that the difference of gamma doses in the TLD500 chips is correlated to the mean fast neutron dose delivered to the moderator material. Different outer shielding materials have been studied. 0.5mm Cadmium shielding is preferred for cost reasons and convenience. Replacement of PE moderator material by other materials like lead or iron at any place is unfavorable. The spatial orientation of the moderator cube is uncritical. Using variance reduction techniques like splitting/Russian roulette, the TLD500 gamma dose simulation give positive differences up to distances of 0.5m from the treatment volume. Conclusion: Applicability and basic layout of a novel clinical neutron dose monitor are demonstrated. The monitor measures PE neutron doses at locations outside the patient body up to distances of 0.5m from the treatment volume. Tissue neutron doses may be calculated using neutron kerma factors

  13. Numerical simulation of a TLD pulsed laser-heating scheme for determination of shallow dose and deep dose in low-LET radiation fields

    International Nuclear Information System (INIS)

    Kearfott, K.J.; Han, S.; Wagner, E.C.; Samei, E.; Wang, C.-K.C.

    2000-01-01

    A new method is described to determine the depth-dose distribution in low-LET radiation fields using a thick thermoluminescent dosimeter (TLD) with a pulsed laser-heating scheme to obtain TL glow output. The computational simulation entails heat conduction and glow curve production processes. An iterative algorithm is used to obtain the dose distribution in the detector. The simulation results indicate that the method can predict the shallow and deep dose in various radiation fields with relative errors less than 20%

  14. Film processing

    International Nuclear Information System (INIS)

    Abdul Nassir Ibrahim; Azali Muhammad; Ab. Razak Hamzah; Abd. Aziz Mohamed; Mohamad Pauzi Ismail

    2008-01-01

    The processing was made not only to show what are in the film but also to produce radiograph with high quality where the information gathered really presented level of the quality of the object inspected. Besides that, good procedure will make the film with good quality can keep the film in long time for reference. Here, more detailed on how the dark room functioned and its design. So, the good procedure while processed the film will be discussed detailed in this chapter from entering the dark room to exit from there.

  15. Demens Film

    DEFF Research Database (Denmark)

    Jensen, Anders Møller

    2012-01-01

    Vi vil skabe film til mennesker med demens – ikke film om demens sygdommen eller beretninger om livet og hverdagen med en kronisk lidelse. Filmene skal medvirke til at frembringe en behagelig stemning omkring og hos mennesker med demens, så hverdagen bliver så tryg som mulig. Filmene skal samtidig...... var at afgrænse og prioritere projektet, samt komme med anbefalinger omkring hvad der er vigtigt, i forbindelse med produktion af film målrettet mennesker med demens. Resultat af ekspertgruppen sammenfattes i denne rapport. Projektet gennemføres som et samarbejde mellem Retrospect Film...

  16. 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.

  17. thin films

    Indian Academy of Sciences (India)

    microscopy (SEM) studies, respectively. The Fourier transform ... Thin films; chemical synthesis; hydrous tin oxide; FTIR; electrical properties. 1. Introduction ... dehydrogenation of organic compounds (Hattori et al 1987). .... SEM images of (a) bare stainless steel and (b) SnO2:H2O thin film on stainless steel substrate at a ...

  18. Into films

    DEFF Research Database (Denmark)

    Tan, Ed S.; Doicaru, Miruna M.; Hakemulder, Frank

    2017-01-01

    Most film viewers know the experience of being deeply absorbed in the story of a popular film. It seems that at such moments they lose awareness of watching a movie. And yet it is highly unlikely that they completely ignore the fact that they watch a narrative and technological construction. Perh...

  19. MCNP SIMULATION OF THE HP(10) ENERGY RESPONSE OF A BRAZILIAN TLD ALBEDO NEUTRON INDIVIDUAL DOSEMETER, FROM THERMAL TO 20 MeV.

    Science.gov (United States)

    Freitas, B M; Martins, M M; Pereira, W W; da Silva, A X; Mauricio, C L P

    2016-09-01

    The Brazilian Instituto de Radioproteção e Dosimetria (IRD) runs a neutron individual monitoring system with a home-made TLD albedo dosemeter. It has already been characterised and calibrated in some reference fields. However, the complete energy response of this dosemeter is not known, and the calibration factors for all monitored workplace neutron fields are difficult to be obtained experimentally. Therefore, to overcome such difficulties, Monte Carlo simulations have been used. This paper describes the simulation of the HP(10) neutron response of the IRD TLD albedo dosemeter using the MCNPX transport code, for energies from thermal to 20 MeV. The validation of the MCNPX modelling is done comparing the simulated results with the experimental measurements for ISO standard neutron fields of (241)Am-Be, (252)Cf, (241)Am-B and (252)Cf(D2O) and also for (241)Am-Be source moderated with paraffin and silicone. Bare (252)Cf are used for normalisation. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Proton/gamma relative thermoluminescence efficiencies of LiF:Mg,Cu,P+PTFE prepared at ININ and TLD-100H

    International Nuclear Information System (INIS)

    Avila, O.; Gonzalez, P.; Murillo, G.

    2009-10-01

    Properties of LiF:Mg,Cu,P+PTFE dosemeters developed at ININ have been investigated in order to evaluate their performance compared to those of equivalent commercial dosemeters. In this work both LiF:Mg,Cu,P+PTFE and TLD-100H pellets were exposed to low fluence 3 MeV protons and to low dose gamma radiation to evaluate experimental proton/gamma efficiencies. Gamma irradiation was performed using the Vic krad irradiator at ININ at varying doses between 25 and 500 mGy. For proton irradiation the Tandem Van de Graaff accelerator at ININ was used. Dosemeters were placed on a holder inside a scattering chamber where protons impinge on a gold target and scatter in all directions. The holder allows for several angular positions so that dosemeters receive proton fluence between 10 6 and 10 1 0 p/cm 2 . Experimental efficiency values found for LiF:Mg,Cu,P+PTFE and TLD-100H were 0.18 +- 03 and 0.23 +- 0.03, respectively. These results allow to confirm the reliability of the dosemeters developed at ININ. (Author)

  1. Comparative study of main dosimetric characteristics between the GR-200A and MCP-N LiF (Mg, Cu, P) TLD chips

    International Nuclear Information System (INIS)

    Shen Wenxiu; Tang Kaiyong; Wang Shoushan; Cai Gangang; Zhu Hongying; Lu Min

    1999-01-01

    GR-200A and MCP-N are the same kind of LiF(Mg, Cu, P) chip detectors. The main dosimetric characteristics of two LiF (Mg, Cu, P) chip TLDs (GR-200A made in Solid Dosimetric Detector and Method Laboratory, Beijing, and MCP-N made in Poland) are compared, including glow curve structure, TL sensitivity, anti-moisture, reproducibility, background, detection threshold and photosensitivity. Sensitivity of GR-200a is 1.6 times as much as that of MCP-N. The sensitivity of GR-200A is stable after being used for six times, but the sensitivity of MCP-N dropped 2.8%, and its colour turned from white into light brown. The sensitivity and colour of GR-200A did not vary after being stored for 25 days at 98% RH, by comparison the sensitivity of MCP-N dropped 14%, and its colour turned into light brown. It was found that the GR-200A TLD is superior to the MCP-N TLD in above-mentioned characteristics

  2. Demens Film

    DEFF Research Database (Denmark)

    Ridder, Hanne Mette Ochsner

    2012-01-01

    I forbindelse med opstarten af Demens Film projektet har der været nedsat en ekspertgruppe, som er kommet med en række anbefalinger omkring film til mennesker med demens. Anbefalingerne skal bruges i de næste faser af projektet. Deltagerne i ekspertgruppen var sammensat af en bred gruppe...... fagpersoner inde for forskellige fagområder. Læs mere om gruppens anbefalinger og sammensætning af ekspertgruppen i den kort rapport som er offentlig tilgængelig. Læs Ekspertgruppe anbefalingerne til Demens Film projekt....

  3. Design and implementation of a ''cheese'' phantom-based Tomotherapy TLD dose intercomparison

    Energy Technology Data Exchange (ETDEWEB)

    Schiefer, Hans; Buchauer, Konrad; Heinze, Simon [Medical Physics Group, Department of Radiation Oncology, St. Gallen (Switzerland); Henke, Guido; Plasswilm, Ludwig [Department of Radiation Oncology, St. Gallen (Switzerland)

    2015-11-15

    The unique beam-delivery technique of Tomotherapy machines (Accuray Inc., Sunnyvale, Calif.) necessitates tailored quality assurance. This requirement also applies to external dose intercomparisons. Therefore, the aim of the 2014 SSRMP (Swiss Society of Radiobiology and Medical Physics) dosimetry intercomparison was to compare two set-ups with different phantoms. A small cylindrical Perspex phantom, which is similar to the IROC phantom (Imaging and Radiation Oncology Core, Houston, Tex.), and the ''cheese'' phantom, which is provided by the Tomotherapy manufacturer to all institutions, were used. The standard calibration plans for the TomoHelical and TomoDirect irradiation techniques were applied. These plans are routinely used for dose output calibration in Tomotherapy institutions. We tested 20 Tomotherapy machines in Germany and Switzerland. The ratio of the measured (D{sub m}) to the calculated (D{sub c}) dose was assessed for both phantoms and irradiation techniques. The D{sub m}/D{sub c} distributions were determined to compare the suitability of the measurement set-ups investigated. The standard deviations of the TLD-measured (thermoluminescent dosimetry) D{sub m}/D{sub c} ratios for the ''cheese'' phantom were 1.9 % for the TomoHelical (19 measurements) and 1.2 % (11 measurements) for the TomoDirect irradiation techniques. The corresponding ratios for the Perspex phantom were 2.8 % (18 measurements) and 1.8 % (11 measurements). Compared with the Perspex phantom-based set-up, the ''cheese'' phantom-based set-up without individual planning was demonstrated to be more suitable for Tomotherapy dose checks. Future SSRMP dosimetry intercomparisons for Tomotherapy machines will therefore be based on the ''cheese'' phantom set-up. (orig.) [German] Die einzigartige Bestrahlungstechnik mit Tomotherapie-Bestrahlungsgeraeten (Accuray Inc., Sunnyvale, CA, USA) erfordert spezifische

  4. Polymer films

    Science.gov (United States)

    Granick, Steve; Sukhishvili, Svetlana A.

    2004-05-25

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  5. Radiotherapy verification film for estimating cumulative entrance skin exposure for fluoroscopic examinations

    International Nuclear Information System (INIS)

    Geise, R.A.; Ansel, H.J.

    1990-01-01

    Measurement of skin entrance exposures during fluoroscopic procedures is complicated by the use of automatic exposure control devices and the presence of contrast media. Due to variability in positioning spot films from patient to patient, standard dosimeters, such as thermoluminescent, cannot be properly placed on the skin prior to examination. Prepackaged film of the type used for portal verification in radiation therapy held next to the patient's skin in a specially modified patient examination gown was found to be useful for determining the entrance skin exposure from both fluoroscopy and spot films during air contrast barium enema exams. The usable sensitivity range of this film has been found satisfactory for exposure measurements at exposures and kVps typically used for gastrointestinal fluoroscopic procedures. Errors in exposure estimates due to changes in film speed and contrast with kVp are less than 5% for the range of kVps used. Errors from variations in beam quality due to the adjacency of scattering material are approximately 5%. Entrance exposures determined with film agreed with those determined from TLD measurements to within 21%, with an average difference of 9%

  6. SU-E-T-222: Investigation of Pre and Post Irradiation Fading of the TLD100 Thermoluminescence Dosimetry for Photon Beams

    International Nuclear Information System (INIS)

    Sina, S; Sadeghi, M; Faghihi, R

    2014-01-01

    Purpose: The pre-irradiation and post-irradiation fading of the Thermoluminescense dosimeter signals were investigated in this study. Methods: Two groups of TLD chips with pre-determined ECC values were used in this study. The two groups were divided into 6 series, each composing of 5 TLD chips.The first group was used for pre-irradiation fading. 5 TLDs were exposed to a known amount of radiation from Cs-137 source, and were read out the next day. After seven days, the other 5 TLDs were exposed to the same amount of radiation and were read out after a day. The other series of 5 TLDs were also exposed after 7,19,28, 59, and 90 days, and were read out a day after irradiation. The loss in TLD signal were obtained for all the above cases. The second group, was used for postirradiation fading. All the TLDs of this group were exposed to a known amount of radiation from Cs-137 source. The 6 series composed of 5 TLDs were read out after 1,7,19,28,59, and 90 days. The above-mentioned procedures for obtaining pre-irradiation, and post-irradiation fading were performed for three storage temperatures (25°C, 4°C, and −18°C). Results: According to the results obtained in this study, in case of pre-irradiation fading study, the signal losses after 90 days are 12%, 24%, and 17% for 25°C, 4°C, and −18°C respectively. In case of post-irradiation fading study, the sensitivity losses after 90 days are 25%, 216%, and 20% for 25°C, 4°C, and −18°C respectively. Conclusion: The results indicate that the optimized time between exposing and reading out, and also the optimized time between annealing and exposing is 1 day.The reduction of Storage temperature will reduce the post-irradiation fading, While temperature reduction does not have any effect on pre-irradiation fading

  7. SU-E-T-222: Investigation of Pre and Post Irradiation Fading of the TLD100 Thermoluminescence Dosimetry for Photon Beams

    Energy Technology Data Exchange (ETDEWEB)

    Sina, S [Radiation Research Center, Shiraz University, Shiraz (Iran, Islamic Republic of); Sadeghi, M [Nuclear Engineering department, Shiraz university, Shiraz (Iran, Islamic Republic of); Faghihi, R [Radiation Research Center, Shiraz University, Shiraz (Iran, Islamic Republic of); Nuclear Engineering department, Shiraz university, Shiraz (Iran, Islamic Republic of)

    2014-06-01

    Purpose: The pre-irradiation and post-irradiation fading of the Thermoluminescense dosimeter signals were investigated in this study. Methods: Two groups of TLD chips with pre-determined ECC values were used in this study. The two groups were divided into 6 series, each composing of 5 TLD chips.The first group was used for pre-irradiation fading. 5 TLDs were exposed to a known amount of radiation from Cs-137 source, and were read out the next day. After seven days, the other 5 TLDs were exposed to the same amount of radiation and were read out after a day. The other series of 5 TLDs were also exposed after 7,19,28, 59, and 90 days, and were read out a day after irradiation. The loss in TLD signal were obtained for all the above cases. The second group, was used for postirradiation fading. All the TLDs of this group were exposed to a known amount of radiation from Cs-137 source. The 6 series composed of 5 TLDs were read out after 1,7,19,28,59, and 90 days. The above-mentioned procedures for obtaining pre-irradiation, and post-irradiation fading were performed for three storage temperatures (25°C, 4°C, and −18°C). Results: According to the results obtained in this study, in case of pre-irradiation fading study, the signal losses after 90 days are 12%, 24%, and 17% for 25°C, 4°C, and −18°C respectively. In case of post-irradiation fading study, the sensitivity losses after 90 days are 25%, 216%, and 20% for 25°C, 4°C, and −18°C respectively. Conclusion: The results indicate that the optimized time between exposing and reading out, and also the optimized time between annealing and exposing is 1 day.The reduction of Storage temperature will reduce the post-irradiation fading, While temperature reduction does not have any effect on pre-irradiation fading.

  8. Investigation of a new LiF TLD individual dosimeter for measuring personal dose equivalent Hp(d) on different phantoms

    International Nuclear Information System (INIS)

    Jin Hua

    1993-01-01

    The paper describes the design of a new LiF TL dosimeter optimized for measuring personal dose equivalent, H p (d). The results obtained with four types of different phantoms, i.e. a PMMA slab, water slab, ICRU sphere and Alderson Rando phantom, and pertinent conversion coefficients show, that the conversion coefficients for the TE slab phantom are suitable for the calibration of TLD individual dosimeters on a PMMA slab phantom. In the energy range 17 keV to 1250 keV the energy response for H 0 (10) and H p (0.07) is within-20% to 8.4% for frontal irradiation. For angles within +- 60 degree the dosimeters indicate H p (10) within 0 to 22.5%, and H p (0.07) within-11.1% to 1.3%. respectively

  9. Experimental determination of relative light conversion factors of TLD-100 for protons with energies from 2.0 to 9.0 MeV

    International Nuclear Information System (INIS)

    Schmidt, P.; Fellinger, J.; Henniger, J.; Huebner, K.

    1988-01-01

    The efficiency of thermoluminescent (TL) detectors to heavy charged particles is described by the so-called light conversion factor η. Relative light conversion factors for protons, alphas and heavier recoils are needed for the calculation of the neutron sensitivity of TL detectors. Such light conversion factors can be determined experimentally. In this paper a method is presented for the experimental determination of relative light conversion factors. Using the experimental arrangement described, relative light conversion factors for LiF material (TLD-100) for protons were determined. In LiF the relative main peak (peak V) efficiency is always lower than 1. It increases with increasing proton energy whereas the relative efficiency of the high temperature peak (peak VI) shows an opposite dependence on the proton energy. Relative light conversion factors for peak VI clearly exceed 1. (orig.)

  10. Studies on dosimetric tests applying source irradiation force of Cs-137 for using in chambers for calibration and TLD type dosimeters

    International Nuclear Information System (INIS)

    Ribeiro, Laila Lorena X.; Barbosa, Rugles Cesar; Correa, Rosangela S.

    2011-01-01

    The West Central region of Brazil does not have a basic infrastructure for research, development, training programs, and personnel dosimetry education. All of them applied to environmental, industrial and medical uses. Service deployment for irradiance of TLD, via 137 Cs irradiator J. L. SHEPHERD model 28-8A (444 activity GBq) in CRCN-CO, it is necessary to introduce procedures for calibration of the radiator and other procedures related to dosimetry and calibration. Such procedures should be repeated periodically, as necessary to introduce techniques that make the service of the CRCN-CO a template, and that meet all standards requirements for radioprotection and operation of dosimetry and calibration. The objective of this work was to evaluate the radiation field of Cs-137, and the automatic system which systematizes the calibration procedures attached to a system control target for the radiator/calibration of monitors, and portable dosimeters. (author)

  11. Experimental determination of relative light conversion factors of TLD-100 for protons with energies from 2.0 to 9.0 MeV

    International Nuclear Information System (INIS)

    Schmidt, P.; Fellinger, J.; Huebner, K.; Henniger, J.

    1985-01-01

    Relative light conversion factors (RLCF) for heavy charged particles (protons, deuterons, recoils) are needed for the calculation of the neutron sensitivity of thermoluminescent (TL) detectors. Such light conversion factors can be determined experimentally. A method is represented for the experimental determination of RLCF. The described experimental facility gives the possibility of irradiation of different luminophor samples with heavy charged particles and flux determination and particle spectrometry at the same time. For the determination of RLCF the doses are needed which are applicated at the irradiation with heavy charged particles and gamma radiation, respectively, and the according detector readings at the TL evaluation. The problems arising at the dose determination are discussed. With this experimental facility the RLCF for TLD-100 for protons were determined. The relative light conversion factors determined according to the light sum method as well as the peak height method are summarizinhly represented and discussed. Furthermore a comparison of the glow curves is made after gamma and proton irradiation

  12. Radiation doses measured by TLD (thermoluminescent dosimeter) in x-ray examination, especially on the skin area beneath of which female gonads situate

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, S; Hiraki, M; Murakami, S; Nishikawa, N; Yagi, T [Nissei Hospital, Osaka (Japan)

    1977-03-01

    By means of TLD, we measured the radiation doses to the skin in the central area of the field of radiation and doses scattered outside of the radiation field, utilizing a phantom to define a suitable radiation field. Clinically, when radiography of the gall bladder and the chest was done, we measured both the radiation doses of the central skin area where radiation was done and the skin above the area of the female gonads. In radiography of the chest, the radiation doses to the skin area above the female gonads situate was under 0.1 mR. When female gonads are less than 15 cm from the margin of the radiation field of the radiation dose can be decreased by 30% if gum sheets containing lead are used to cover the skin area outside the radiation field.

  13. Determination of exposure rates from natural background radiation in Khartoum using LiF:Mg,Cu,P (GR-200) and CaSo4: Mn TLD chips

    International Nuclear Information System (INIS)

    Suliman, I.I.; Khangi, F.A.; Shaddad, I.A.; Suliman, I.A.; El Amin, O.I.

    2002-01-01

    The exposure rates from natural background radiation - including terrestrial gamma radiation and the ionizing component of cosmic rays - were measured for the first time in the city of khartoum using two types of TLD materials: LiF:Mg,Cu,P (GR-200) and CaSo 4 :Mn TLD chips. Measurements were performed at two sites simultaneously, one site was selected on land in the vicinity of the Sudan Atomic Energy Commission, for the purposes of the measurement of the total exposure rate outdoors, while the other site was located on a buoy anchored in the Blue Nile, and was selected to measure the exposure rate due to the ionizing component of cosmic rays. The investigations were conducted for periods of between 5 and 28 days. Calibration was performed on a selected number of dosimeters to determine the exposure rates at each site. The exposure rates from the ionizing component of cosmic rays in Khartoum were found to be respectively 33 nGy.h -1 and 30 nGy.h -1 , in the measurements performed within the scope of this work using GR-200 and CaSo 4 :Mn dosimeters, while the total values for exposure on land were found to be 45 nGy.h -1 and 42 nGy.h -1 respectively. These values compare reasonably well with other national averages reported in the UNSCEAR publication. The comparison of the results for the two dosimetric materials demonstrates both the sensitivity and suitability of GR-200 for the purposes of environmental monitoring (orig.)

  14. Science Fiction on Film.

    Science.gov (United States)

    Burmester, David

    1985-01-01

    Reviews science fiction films used in a science fiction class. Discusses feature films, short science fiction films, short story adaptations, original science fiction pieces and factual science films that enrich literature. (EL)

  15. Dosimetric parameters for small field sizes using Fricke xylenol gel, thermoluminescent and film dosimeters, and an ionization chamber

    International Nuclear Information System (INIS)

    Guzman Calcina, Carmen S; Oliveira, Lucas N de; Almeida, Carlos E de; Almeida, Adelaide de

    2007-01-01

    Dosimetric measurements in small therapeutic x-ray beam field sizes, such as those used in radiosurgery, that have dimensions comparable to or smaller than the build-up depth, require special care to avoid incorrect interpretation of measurements in regions of high gradients and electronic disequilibrium. These regions occur at the edges of any collimated field, and can extend to the centre of small fields. An inappropriate dosimeter can result in an underestimation, which would lead to an overdose to the patient. We have performed a study of square and circular small field sizes of 6 MV photons using a thermoluminescent dosimeter (TLD), Fricke xylenol gel (FXG) and film dosimeters. PMMA phantoms were employed to measure lateral beam profiles (1 x 1, 3 x 3 and 5 x 5 cm 2 for square fields and 1, 2 and 4 cm diameter circular fields), the percentage depth dose, the tissue maximum ratio and the output factor. An ionization chamber (IC) was used for calibration and comparison. Our results demonstrate that high resolution FXG, TLD and film dosimeters agree with each other, and that an ionization chamber, with low lateral resolution, underestimates the absorbed dose. Our results show that, when planning small field radiotherapy, dosimeters with adequate lateral spatial resolution and tissue equivalence are required to provide an accurate basic beam data set to correctly calculate the absorbed dose in regions of electronic disequilibrium

  16. Dosimetric evaluation of the response of the TLD-100 dosemeters in the IMRT technique by 'Step and Shoot'; Evaluacion dosimetrica de la respuesta de los dosimetros TLD-100 en la tecnica de IMRT por 'Step and Shoot'

    Energy Technology Data Exchange (ETDEWEB)

    Vasquez, J. [Fundacion Clinica Valle del Lili, A.A. 020338, Cali (Colombia); Benavides, S.O. [Depto. de Fisica, Universidad del Valle, A.A. 25360, Cali (Colombia)

    2005-07-01

    We show the results of the dosimetry response of LiF thermoluminescent crystals: TLD-100, where they were radiated in a linear accelerator Siemens Primus Hl using the Intensity Modulated Radiation Therapy (IMRT) by step and shoot technique. Previous to the crystals calibration and response evaluation, the acceptation procedures recommended by the TG-53 protocol for validation of the technique were carried out. The planning system utilized was the Theraplan Plus 3.8, using the algorithm of Pencil Kernel. The register and verification system was Lantis 5.2. The response curve of dose versus charge was obtained from the readings of the TLD in a Harshaw 3500. The crystals were radiated in a Bench- Marck phantom with doses previously determined by using ionization chambers for square radiation fields, in a beam with a 0.68 TPR20,10 corresponding to 6 MV of energy. We compare the response of these through of radiation of segmented fields in a Anthropomorphic phantom and the calculated doses by the planning system. The results obtained in the crystals response show deviations less than 5 % between the measured dose and the calculated dose in the zones of low gradient. It allows its implementation like routine control of quality by IMRT. (Author)

  17. Black Films and Film-Makers.

    Science.gov (United States)

    Patterson, Lindsay, Ed.

    The development of black films and the attitudes of the film industry toward black films and black actors are some of the topics examined in this anthology of essays. Section 1, "Nigger to Supernigger," contains such articles as "The Death of Rastus: Negroes in American Films" by Thomas R. Cripps and "Folk Values in a New Medium" by Alain Locke…

  18. In-situ Long-range Alpha Particles and X-ray Detection for Thin-film Pd Cathodes During Electrolysis in Li_2SO_4/H_2O

    Science.gov (United States)

    Lipson, A. G.; Roussetski, A. S.; Castano, C. H.; S-O, Kim; Miley, G. H.

    2002-03-01

    Measurements of long-range alpha and soft X-ray emissions have been performed using cyclotron calibrated CR-39 plastic track and LiF/Al_2O_3:C-Thermo-Luminescent (TLD) detectors. Application of CR-39 and TLD detectors to the surface of the thin Pd film-cathodes sputtered on the insulator substrate (glass, Al_2O_3, PMMA) allows detection of both alpha and soft X-ray emissions simultaneously with excess heat measurements during electrolysis using 1 Molar Li_2SO_4/H_20 electrolyte. The alpha particles in the range of 8.0 d> 6.0 μm) were detected upon the electrolysis. Those alpha-tracks are quite unique, never having been observed during CR-39 exposure with trans-uranium alpha -sources (Am^241, Pu^239). The TLD measurement shows generation of the low intensity 5.0-10.0 keV X-ray quanta (Φx < 5.0 s -1*cm-2) accompanying the alpha emission.

  19. Characterization of TLD-100 in powders for dosimetric quality control of 192 Ir sources used in brachytherapy of high dose rate

    International Nuclear Information System (INIS)

    Loaiza C, S.P.

    2007-01-01

    The Secondary Standard Dosimetric at the National Institute of Nuclear Research (ININ) calibrated a lot of powdered TLD-100 (LiF:Mg,Ti) in terms of absorbed dose to water D w for the energy of: 60 Co, 137C s, X rays of 250 and 50 kVp. Later on, it is carried out an interpolation of the calibration for the energy of the 192 Ir. This calibration is part of a dosimetric quality control program, to solve the problems of traceability for the measurements carried out by the users of 192 Ir sources employed in the treatments of High Dose Rate Brachytherapy (HDR) at the Mexican Republic. The calibrations of the radiation beams are made with the following protocols: IAEA TRS-398 for the 60 Co for D w , using a secondary standard ionization chamber PTW N30013 calibrated in D w by the National Research Council (NRC, Canada). AAPM TG-43 for D w in terms of the strength kerma Sk, calibrating this last one quantity for the 137 Cs radioactive source, with a well chamber HDR 1000 PLUS traceable to the University of Wisconsin (US). AAPM TG-61 for X ray of 250 and 50 kVp for D w start to Ka using field standard a Farmer chamber PTW 30001 traceable to K for the Central Laboratory of Electric Industries (CLEI, France). The calibration curves (CC) they built for the response of the powder TLD: R TLD vs D w : For the energy of 60 Co, 137 Cs, X rays of 250 and 50 kVp. Fitting them with the least square method weighed by means of a polynomial of second grade that corrects the supra linearity of the response. iii. Each one of the curves was validated with a test by lack of fitting and for the Anderson Darling normality test, using the software MINITAB in both cases. iv. The sensibility factor (F s ) for each energy corresponds to the slope of the CC, v. The F s for the two 192 Ir sources used are interpolated: one for a Micro Selectron source and the other one a Vari Source source. Finally, a couple of capsules were sent to two hospitals that have the HDR Brachytherapy with sources of 192

  20. Estimation of eye lens dose during brain scans using Gafchromic XR-QA2 film in various multidetector CT scanners

    International Nuclear Information System (INIS)

    Akhilesh, Philomina; Jamhale, Shramika H.; Sharma, S.D.; Kumar, Rajesh; Datta, D.; Kulkarni, Arti R.

    2017-01-01

    The purpose of this study was to estimate eye lens dose during brain scans in 16-, 64-, 128- and 256-slice multidetector computed tomography (CT) scanners in helical acquisition mode and to test the feasibility of using radiochromic film as eye lens dosemeter during CT scanning. Eye lens dose measurements were performed using Gafchromic XR-QA2 film on a polystyrene head phantom designed with outer dimensions equivalent to the head size of a reference Indian man. The response accuracy of XR-QA2 film was validated by using thermoluminescence dosemeters. The eye lens dose measured using XR-QA2 film on head phantom for plain brain scanning in helical mode ranged from 43.8 to 45.8 mGy. The XR-QA2 film measured dose values were in agreement with TLD measured dose values within a maximum variation of 8.9%. The good correlation between the two data sets confirms the viability of using XR-QA2 film for eye lens dosimetry. (authors)

  1. The effect of sample/planchet geometry and temperature resolution on the reproducibility of glow curve shapes and precision of dose measurement in LiF-TLD-100 thermoluminescent dosimetry

    International Nuclear Information System (INIS)

    Sibony, D.; Horowitz, Y.; Oster, L.

    2014-01-01

    The effect of accurate positioning of TLD-100 samples in the center of the reader planchet on precision and kinetic parameters was investigated. Significant improvement in precision is obtained by careful positioning of the sample in the center of the planchet, by as much as 40%, 20% and 30% using different methods of glow curve analysis to estimate the intensity of the TL signal. - Highlights: • The effect of accurate positioning of TLD-100 samples on precision and kinetic parameters was investigated. • Significant improvement in precision was obtained. • Significant improvement in the calculation of the kinetic parameters of individual peaks was achieved. • The optimum protocol involves a depression matched to the size of the sample was developed

  2. Design, fabrication, installation and shielding integrity testing of source storage container for automatic source movement system used in TLD calibration facility

    International Nuclear Information System (INIS)

    Subramanian, V.; Baskar, S.; Annalakshmi, O.; Jose, M.T.; Jayshree, C.P.; Choudry, Shreelatha

    2012-01-01

    A state-of-art TLD laboratory has been commissioned in January 2000 at Radiological Safety Division of Indira Gandhi Centre for Atomic Research (IGCAR). The laboratory provides personnel monitoring service to 2000 occupational workers from Indira Gandhi Centre for Atomic Research and Bhabha Atomic Research Centre facilities. The laboratory has been accredited by the Radiation Safety Systems Division (RSSD), Bhabha Atomic Research Centre (BARC) since year 2002. The laboratory has exclusive facility for the calibration of the TLD cards. As apart of accreditation procedure and taking into account of geometry effect, the dose rate at the card position is determined by the accreditation authorities by using graphite chamber (secondary or national standard instrument) and often re estimated by a condenser R meter (M/s Victoreen, Germany) by our laboratory. As per the regulatory requirement, the exposure protocols should be automated. Towards this an automatic source movement system has been augmented in the calibration facility. By using the system, the source will be brought to the irradiation position by pneumatically and exposures will be terminated by counter, timer and triggering system. To accomplish this task a lead container has been designed, fabricated and mounted at the beneath of the calibration table for the storage of source. As per the automation process, a lead container for the source storage has been designed and installed beneath to the Calibration Table. The container was designed to hold a 3Ci 137 Cs source, but present activity of the source is 1.2Ci. Hence, the shielding integrity was tested with higher active source (1.7Ci 60 Co). The dose rate measured outside on the circumference of the container at the middle of the source is found to be the same as calculated using QAD CGGP calculations. The top plug is so designed to avoid inadvertent upward movement of the source. Though, the shielding was not adequate on top of the top plug, however it does

  3. Film: An Introduction.

    Science.gov (United States)

    Fell, John L.

    "Understanding Film," the opening section of this book, discusses perceptions of and responses to film and the way in which experiences with and knowledge of other media affect film viewing. The second section, "Film Elements," analyzes the basic elements of film: the use of space and time, the impact of editing, sound and color, and the effects…

  4. Film and History.

    Science.gov (United States)

    Schaber, Robin L.

    2002-01-01

    Provides an annotated bibliography of Web sites that focus on using film to teach history. Includes Web sites in five areas: (1) film and education; (2) history of cinema; (3) film and history resources; (4) film and women; and (5) film organizations. (CMK)

  5. Application of artificial neural network for development of an algorithm for TLD badge system in the mixed field dosimetry of X and gamma radiation in terms of Hp(10)

    International Nuclear Information System (INIS)

    Srivastava, K.; Bakshi, A.K.; Geetha, V.; Kher, R.K.; Dhar, V.K.

    2005-01-01

    ICRU has introduced new operational quantities for individual monitoring. Therefore it is required to develop an algorithm that gives direct response of the TLD badge in terms of the operational quantities. For this purpose and also to improve the precision in the mixed fields dosimetry, two methods were studied i)- analytical method by developing an algorithm based on of higher order polynomial fit of the data points for known delivered doses and ii) use of Artificial Neural Network (ANN). Study on the response of the TLD badge system based on CaSO 4 : Dy Teflon TLD discs in the mixed fields of X and gamma radiation in terms of operational quantity Hp(10) was carried out using the prevalent algorithm, algorithm developed using higher order polynomial and neural network predicted algorithm for different proportion of dose delivered by X and gamma radiations. It was found that the uncertainties in the dose response for few fields are beyond the acceptable limit for prevalent algorithm and within the acceptable limit for other two algorithms. Algorithm based on ANN gives higher precision in the mixed field of two radiations compared to other two algorithms. (author)

  6. Measurement of the Dose to the Family Members Taking Care of Thyroid Cancer Patients Undergoing I-131 Therapy in Nuclear Medicine Using TLD-100.

    Science.gov (United States)

    Zehtabian, M; Dehghan, N; Danaei Ghazanfarkhani, M; Haghighatafshar, M; Sina, S

    2017-05-01

    The family members or friends of the patients undergoing treatment using radioiodine in nuclear medicine are inevitably exposed to ionization radiation. The purpose of this study is measurement of the dose received by the people taking care of the thyroid cancer patients treated by 131I. For this purpose, the dose amounts received by 29 people accompanying patients were measured using thermoluminescence dosimeters. A badge containing three TLD-100 chips was given to each caregiver. The people were asked to wear the badges for 24 days, when they are taking care of the patients. Finally the dose to each person was estimated by averaging the readings of the three TLDs. The measured dose amounts to the people were compared with the recommendations of international commitions. According to the results obtained in this study, the amounts of dose received by the caregivers were between 0.03 and 0.38 mSv, with the average of 0.12 mSv. By comparison of the results of this study with the recommendations of International Commission on Radiological Protection (ICRP), it can be observed that the dose to family members of the patients is less than the dose constraints. However, it is recommended that the caregivers be aware of the radiation protection principles in order to reduce their dose. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Comparison of the calculated absorbed dose using the Cadplan™ treatment planning software and Tld-100 measurements in an Alderson-Rando phantom for a bronchogenic treatment

    Energy Technology Data Exchange (ETDEWEB)

    Gutiérrez Castillo, J. G., E-mail: jggc59@hotmail.com [Departamento de Física, Hospital de Oncología, IMSS, CMN Siglo XXI, Cuauhtémoc 330 Col. Doctores (Mexico); Álvarez Romero, J. T., E-mail: trinidad.alvarez@inin.gob.mx, E-mail: fisarmandotorres@gmail.com, E-mail: victor.tovar@inin.gob.mx; Calderón, A. Torres, E-mail: trinidad.alvarez@inin.gob.mx, E-mail: fisarmandotorres@gmail.com, E-mail: victor.tovar@inin.gob.mx; M, V. Tovar, E-mail: trinidad.alvarez@inin.gob.mx, E-mail: fisarmandotorres@gmail.com, E-mail: victor.tovar@inin.gob.mx [SSDL, Departamento de Metrología ININ, Salazar, Estado de México 15245 (Mexico)

    2014-11-07

    To verify the accuracy of the absorbed doses D calculated by a TPS Cadplan for a bronchogenic treatment (in an Alderson-Rando phantom) are chosen ten points with the following D's and localizations. Point 1, posterior position on the left edge with 136.4 Gy. Points: 2, 3 and 4 in the left lung with 104.9, 104.3 and 105.8 Gy, respectively; points 5 and 6 at the mediastinum with 192.4 and 173.5 Gy; points 7, 8 and 9 in the right lung with 105.8, 104.2 and 104.7 Gy, and 10 at posterior position on right edge with 143.7 Gy. IAEA type capsules with TLD 100 powder are placed, planned and irradiated. The evaluation of the absorbed dose is carried out a curve of calibration for the LiF response (nC) {sup vs} {sup DW}, to several cavity theories. The traceability for the DW is obtained with a secondary standard calibrated at the NRC (Canada). The dosimetric properties for the materials considered are determined from the Hounsfield numbers reported by the TPS. The stopping power ratios are calculated for nominal spectrum to 6 MV photons. The percent variations among the planned and determined D in all the cases they are < ± 3%.

  8. Measurement of the dose to the family members taking care of thyroid cancer patients undergoing I-131 therapy in nuclear medicine using TLD-100

    International Nuclear Information System (INIS)

    Zehtabian, M.; Dehghan, N.; Danaei Ghazanfarkhani, M.; Haghighatafshar, M.; Sina, S.

    2017-01-01

    The family members or friends of the patients undergoing treatment using radioiodine in nuclear medicine are inevitably exposed to ionization radiation. The purpose of this study is measurement of the dose received by the people taking care of the thyroid cancer patients treated by "1"3"1I. For this purpose, the dose amounts received by 29 people accompanying patients were measured using thermoluminescence dosimeters. A badge containing three TLD-100 chips was given to each caregiver. The people were asked to wear the badges for 24 days, when they are taking care of the patients. Finally the dose to each person was estimated by averaging the readings of the three TLDs. The measured dose amounts to the people were compared with the recommendations of international commissions. According to the results obtained in this study, the amounts of dose received by the caregivers were between 0.03 and 0.38 mSv, with the average of 0.12 mSv. By comparison of the results of this study with the recommendations of International Commission on Radiological Protection (ICRP), it can be observed that the dose to family members of the patients is less than the dose constraints. However, it is recommended that the caregivers be aware of the radiation protection principles in order to reduce their dose. (authors)

  9. Angular and radial dependence of the energy response factor for LiF-TLD micro-rods in 125I permanent implant source

    International Nuclear Information System (INIS)

    Mobit, P.; Badragan, I.

    2006-01-01

    EGSnrc Monte Carlo simulations were used to calculate the angular and radial dependence of the energy response factor for LiF-thermoluminescence dosemeters (TLDs) irradiated with a commercially available 125 I permanent brachytherapy source. The LiF-TLDs were modelled as cylindrical micro-rods of length 6 mm and with diameters of 1 mm and 5 mm. The results show that for a LiF-TLD micro-rod of 1 mm diameter, the energy response relative to 60 Co gamma rays is 1.406 ± 0.3% for a polar angle of 90 deg. and radial distance of 1.0 cm. When the diameter of the micro-rod is increased from 1 to 5 mm, the energy response decreases to 1.32 ± 0.3% at the same point. The variation with position of the energy response factor is not >5% in a 6 cm x 6 cm x 6 cm calculation grid for the 5 mm diameter micro-rod. The results show that there is a change in the photon spectrum with angle and radial distance, which causes the variation of the energy response. (authors)

  10. Ferroelectric ultrathin perovskite films

    Science.gov (United States)

    Rappe, Andrew M; Kolpak, Alexie Michelle

    2013-12-10

    Disclosed herein are perovskite ferroelectric thin-film. Also disclosed are methods of controlling the properties of ferroelectric thin films. These films can be used in a variety materials and devices, such as catalysts and storage media, respectively.

  11. Film Noir Style Genealogy

    OpenAIRE

    Rietuma, Dita

    2012-01-01

    Annotation for the Doctoral Work Film Noir Style Genealogy (The Genealogy of the Film Noir Style) The doctoral work topic Film Noir Style Genealogy encompasses traditionally approved world film theory views on the concept of film noir and its related cinematographic heritage, and an exploration of its evolution and distinctive style, including – the development of film noir in the USA, Europe, and also in Latvia, within the context of both socio-political progression and the paradigm of m...

  12. Contemporary Films' Mini Course on Film Study.

    Science.gov (United States)

    Schillaci, Peter

    This minicourse on film study can be a unit in English, in arts, or in the humanities. It can help to launch a film study course or complement an introduction to theater. Whatever form it takes, it helps to build a bridge to the student's media environment. Part one, the language of images, utilizes four films which demonstrate the basic elements…

  13. The Evolution of Film: Rethinking Film Studies

    OpenAIRE

    Harbord, Janet P.

    2007-01-01

    How is film changing? What does it do, and what do we do with it? This book examines the reasons why we should be studying film in the twenty-first century, connecting debates from philosophy, anthropology and new media with historical concerns of film studies.

  14. Film quality in film mammography. Pt. 2

    International Nuclear Information System (INIS)

    Friedrich, M.; Weskamp, P.; Freie Univ. Berlin

    1976-01-01

    During consideration of three film mammographic systems, the concept of signal/noise ratio is developed as a quantitative measure of film quality. The ability to recognise detail related to detail size, film blackening and exposure geometry was studied for various systems, and the quality profiles are discussed. There is a considerable difference in quality between industrial films without screens and film-screen combinations; however, exposure geometry during mammography has a considerable effect which tends to reduce the difference. Consequently, detail sizes of 200 μ to 1,000 μ (including the majority of mammographic micro-calcifications) are shown about equally well. Contrast for the lo-dose system is somewhat less than for adequately exposed industrial film. Over-exposure with the lo-dose system, contrary to industrial film, rapidly leads to unsatisfactory results. On the other hand it is often not possible to obtain an adequate exposure when using industrial film. For these reasons it is often an advantage to examine large breasts and the dense breasts of young women with a film-screen combination which requires approximately one eighth of the dose necessary for industrial film. For small or easily compressable breasts best results are obtained, using an adequate exposure by employing industril film; radiation dose it then acceptable. (orig./ORU) [de

  15. Uniformly irradiated polymer film

    International Nuclear Information System (INIS)

    Fowler, S.L.

    1979-01-01

    Irradiated film having substantial uniformity in the radiation dosage profile is produced by irradiating the film within a trough having lateral deflection blocks disposed adjacent the film edges for deflecting electrons toward the surface of the trough bottom for further deflecting the electrons toward the film edge

  16. Films and dark room

    International Nuclear Information System (INIS)

    Abdul Nassir Ibrahim; Azali Muhammad; Ab. Razak Hamzah; Abd. Aziz Mohamed; Mohamad Pauzi Ismail

    2008-01-01

    After we know where the radiographic come from, then we must know about the film and also dark room. So, this chapter 5 discusses the two main components for radiography work that is film and dark room, places to process the film. Film are structured with three structured that are basic structured, emulsion and protection structured. So, this film can be classified either with their speed, screen and standard that used. The process to wash the film must be done in dark room otherwise the radiographer cannot get what are they inspected. The processing of film will be discussed briefly in next chapter.

  17. Characterization of TLD-100 in powders for dosimetric quality control of {sup 192} Ir sources used in brachytherapy of high dose rate; Caracterizacion de TLD-100 en polvo para control de calidad dosimetrico de fuentes de Ir{sup 192} usadas en braquiterapia de alta tasa de dosis

    Energy Technology Data Exchange (ETDEWEB)

    Loaiza C, S.P

    2007-07-01

    The Secondary Standard Dosimetric at the National Institute of Nuclear Research (ININ) calibrated a lot of powdered TLD-100 (LiF:Mg,Ti) in terms of absorbed dose to water D{sub w} for the energy of: {sup 60}Co, {sup 137C}s, X rays of 250 and 50 kVp. Later on, it is carried out an interpolation of the calibration for the energy of the {sup 192}Ir. This calibration is part of a dosimetric quality control program, to solve the problems of traceability for the measurements carried out by the users of {sup 192}Ir sources employed in the treatments of High Dose Rate Brachytherapy (HDR) at the Mexican Republic. The calibrations of the radiation beams are made with the following protocols: IAEA TRS-398 for the {sup 60}Co for D{sub w}, using a secondary standard ionization chamber PTW N30013 calibrated in D{sub w} by the National Research Council (NRC, Canada). AAPM TG-43 for D{sub w} in terms of the strength kerma Sk, calibrating this last one quantity for the {sup 137}Cs radioactive source, with a well chamber HDR 1000 PLUS traceable to the University of Wisconsin (US). AAPM TG-61 for X ray of 250 and 50 kVp for D{sub w} start to Ka using field standard a Farmer chamber PTW 30001 traceable to K for the Central Laboratory of Electric Industries (CLEI, France). The calibration curves (CC) they built for the response of the powder TLD: R{sub TLD} vs D{sub w}: For the energy of {sup 60}Co, {sup 137}Cs, X rays of 250 and 50 kVp. Fitting them with the least square method weighed by means of a polynomial of second grade that corrects the supra linearity of the response. iii. Each one of the curves was validated with a test by lack of fitting and for the Anderson Darling normality test, using the software MINITAB in both cases. iv. The sensibility factor (F{sub s}) for each energy corresponds to the slope of the CC, v. The F{sub s} for the two {sup 192}Ir sources used are interpolated: one for a Micro Selectron source and the other one a Vari Source source. Finally, a couple of

  18. Poster - 24: Characterization of the energy dependence of high-sensitivity MCP-N TLD and Al2O3:C OSLD in-vivo dosimetry systems for 40–100 kVp energies

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, Yannick; Kuznetsova, Svetlana; Barajas, Eduardo Villarreal [Tom Baker Cancer Centre, Calgary AB, University of Calgary, Calgary AB, Tom Baker Cancer Center/University of Calgary, Calgary AB (Canada)

    2016-08-15

    Purpose: To characterize the energy dependence of high-sensitivity MCP-N TLD and Al{sub 2}O{sub 3}:C OSLD dosimetry systems at low (40–100 kVp) energies for in-vivo dosimetry. Methods: We assessed the variation of response with energy of two detectors in the 40–100 kVp energy range: high-sensitivity MCP-N TLDs (LiF:Mg,Cu,P) and OSLDs (Al{sub 2}O{sub 3}:C). The detectors were irradiated with an XRad 320ix biological irradiator under reference conditions. The delivered dose was 10 cGy for 7 beam qualities ranging from 40–100 kVp, 1.7–4.0 mm Al, and effective energies 26.9–37.9 keV. Both sets of detectors were also irradiated under reference conditions at 6 MV using a Varian Clinac 21Ex to assess the change in response from high-energy beams. Results: The MCP-N high-sensitivity TLDs were relatively insensitive to energies in the kV range, as their response varied by ±5%, i.e. well within the reproducibility limits of these detectors. However, the OSLDs exhibited a linearly-decreasing response with energy with a response 18.7% higher at 40 kVp than at 100 kVp for the same nominal dose. Compared to the 6 MV beams used in conventional radiotherapy, OSLDs responded 3.3–3.9 times higher depending on beam quality while the MCP-N TLD response was unchanged within experimental uncertainty. Conclusions: Unlike the more commonly used TLD-100, the high-sensitivity MCP-N TLDs exhibit little to no energy response. OSLDs are shown to be highly energy-dependent, both from MV to kV and within the kV range.

  19. Film som kunst

    DEFF Research Database (Denmark)

    Petersen, Anne Ring

    2013-01-01

    Films by artists induce scholars to work across art, film and cultural history. Accordingly, this article adopts an interdisciplinary approach to the British-Nigerian artist Yinka Shonibare’s film Un Ballo in Maschera (2004). The film is grounded in Shonibare’s unique use of African-print fabric...... in conjunction with references to European cultural and political history, but the film is also – it is alleged – rooted in Black British cinema and the transnational postcolonialism which emerged in the UK of the 1980s. The article starts with a general introduction to Shonibare’s art and the colonial...... connotations of the African-print fabric, which are also central to the critique of power in Un Ballo in Maschera. Its critical agenda is then analysed and put into historical perspective by relating the film to Black British film. A comparison with the Black Audio Film Collective’s key work Handsworth Songs...

  20. The Educational Film Industry

    Science.gov (United States)

    Tortora, Vincent R.; Schillaci, Peter

    1975-01-01

    Increased dialog is needed among educational film producers, distributors, and consumers in order to be sure that what is being produced meets educators' needs and also to help solve the financial problems of the film industry. (LS)

  1. Electrochromic nanocomposite films

    Science.gov (United States)

    Milliron, Delia; Llordes, Anna; Buonsanti, Raffaella; Garcia, Guillermo

    2018-04-10

    The present invention provides an electrochromic nanocomposite film. In an exemplary embodiment, the electrochromic nanocomposite film, includes (1) a solid matrix of oxide based material and (2) transparent conducting oxide (TCO) nanostructures embedded in the matrix. In a further embodiment, the electrochromic nanocomposite film farther includes a substrate upon which the matrix is deposited. The present invention also provides a method of preparing an electrochromic nanocomposite film.

  2. Lars von Triers film

    DEFF Research Database (Denmark)

    Nielsen, Lisbeth Overgaard

    2007-01-01

    Afhandlingen undersøger Lars von Triers filmæstetik, som den kommer til udtryk i spillefilmene fra perioden 1984-2007. Afhandlingen analyserer de enkelte films stil, virkningsstrategi og betydningsdannelse.......Afhandlingen undersøger Lars von Triers filmæstetik, som den kommer til udtryk i spillefilmene fra perioden 1984-2007. Afhandlingen analyserer de enkelte films stil, virkningsstrategi og betydningsdannelse....

  3. Defining Documentary Film

    DEFF Research Database (Denmark)

    Juel, Henrik

    2006-01-01

    A discussion of various attemts at defining documentary film regarding form, content, truth, stile, genre or reception - and a propoposal of a positive list of essential, but non-exclusive characteristica of documentary film......A discussion of various attemts at defining documentary film regarding form, content, truth, stile, genre or reception - and a propoposal of a positive list of essential, but non-exclusive characteristica of documentary film...

  4. Dosimetry and LET spectrometry in C 290 MeV/n and Ne 400 MeV/n HIMAC ion beam by different TLD's, TED based LET spectrometers, and Si energy-deposition spectrometer

    International Nuclear Information System (INIS)

    Spurny, F.; Brabcova, K.; Jadrnickova, I.; Uchihori, Y.; Kitamura, H.; Yasuda, N.; Molokanov, A. G.

    2009-01-01

    The sets of track etched detectors based (TED) spectrometer's of the linear energy transfer (LET) have been, together with two types of thermoluminescent detectors (TLD)and MDU- Liulin energy deposition spectrometer exposed in the C 290 MeV/n and Ne 400 MeV/n ion beams at the HlMAC installation at NIRS, Chiba, Japan. The experiment has been performed in the frame of NPI project 20P241 agreed by HlMAC P AC at the beginning of 2008 year. Up to now, moxstle only results obtained in C-ion beam have been treated and analyzed. Sets of TED spectrometer's and TLD detectors have been exposed in 19 depths in the C-ion beam with expected LET values of primary particles from 13 keV/μm in water, through the Bragg peak area up to two depth behind the Bragg peak. The contribution of fragments to total number of events, and to the energy absorbed in Si has been determined, when possible separately for different fragments. In all cases also total contribution of fragments (and other secondary particles) to the total number of energy deposition events and to the absorbed dose has been estimated. LET and energy deposition spectra obtained will be compared together , a good agreement of data has bee stated. Some of results have been also compared with those obtained by calculation by means of PHITS code. (authors)

  5. Implementing a new TLD system

    International Nuclear Information System (INIS)

    Rhea, T.A.

    1988-01-01

    Martin Marietta Energy Systems will soon be issuing new personnel dosimeters at four of their five Department of Energy (DOE) facilities, The Piketon, Ohio uranium enrichment facility is not included in this dosimetry upgrade program. This talk will focus on the ORNL perspective of this program, especially the new beta-gamma dosimeter. Neutron dosimetry will be discussed briefly. The objective of this upgrade is to put in place a state-of-the-art personnel dosimetry system and to meet the recent DOE Laboratory Accreditation Program performance criteria. Processing such a large number of dosimeters will require stringent quality controls. Approximately 18,000 beta-gamma dosimeters are scheduled for issue in January 1989. 15 figs

  6. Personnel photographic film dosimetry

    International Nuclear Information System (INIS)

    Keirim-Markus, I.B.

    1981-01-01

    Technology of personnel photographic film dosimetry (PPD) based on the photographic effect of ionizing radiation is described briefly. Kinds of roentgen films used in PPD method are enumerated, compositions of a developer and fixing agents for these films are given [ru

  7. Radiochromic film dosimetry

    International Nuclear Information System (INIS)

    Xu Zhiyong

    2002-01-01

    Radiochromic film dosimetry was developed to measure ionization irradiation dose for industry and medicine. At this time, there are no comprehensive guideline on the medical application, calibration method and densitometer system for medicine. The review gives update on Radiochromic film dosimetry used for medicine, including principles, film model and material, characteristics, calibration method, scanning densitometer system and medical application

  8. Australian Film Studies.

    Science.gov (United States)

    Breen, Myles P.

    Although Australia had a vigorous film industry in the silent film era, it was stifled in the 1930s when United States and British interests bought up the Australian distribution channels and closed down the indigenous industry. However, the industry and film study have undergone a renaissance since the advent of the Labor government in 1972,…

  9. Getting into Film.

    Science.gov (United States)

    London, Mel

    This book describes the various aspects of the film industry and the many jobs related to filmmaking, stressing that no "formula" exists for finding a successful career in the film industry. Chapters provide information on production, writing for film, cinematography, editing, music, sound, animation and graphics, acting and modeling, the "unsung…

  10. The Sponsored Film.

    Science.gov (United States)

    Klein, Walter J.

    For public relations professionals and would-be sponsors of films, this book provides guidelines for understanding the film medium and its potential as a persuasive force in industry, government, organizations, and religious orders. For filmmakers, it brings together practical information needed to survive in the sponsored-film industry and to…

  11. Introduction to Film Making.

    Science.gov (United States)

    Davis, Robert E.

    This booklet is intended for teachers who are now teaching units in film production as part of a program in communication or who wish to begin work with filmmaking in such a program. The first section is intended to serve as a brief introduction to film theory, while a major portion of the rest of the booklet is devoted to film projects which may…

  12. Teaching Culture Through Films

    Institute of Scientific and Technical Information of China (English)

    徐婷

    2016-01-01

    Cultural teaching is an issue which is associated with complexity and paradox and also it is a big challenge for faculty. Teaching culture through films has become an important way of cross-cultural teaching This paper focuses on the reasons for teaching culture through films, the value and how it works. And finally it leads out the prospects of cultural teaching through films.

  13. Film studies the basics

    CERN Document Server

    Villarejo, Amy

    2013-01-01

    Film Studies: The Basics is a compelling guide to the study of cinema in all its forms. This second edition has been thoroughly revised and updated to take account of recent scholarship, the latest developments in the industry and the explosive impact of new technologies. Core topics covered include:   The history, technology and art of cinema Theories of stardom, genre and film-making The movie industry from Hollywood to Bollywood Who does what on a film set   Complete with film stills, end-of-chapter summaries and a substantial glossary, Film Studies: The Basics is the ideal introduction to those new to the study of cinema.

  14. Thin film processes II

    CERN Document Server

    Kern, Werner

    1991-01-01

    This sequel to the 1978 classic, Thin Film Processes, gives a clear, practical exposition of important thin film deposition and etching processes that have not yet been adequately reviewed. It discusses selected processes in tutorial overviews with implementation guide lines and an introduction to the literature. Though edited to stand alone, when taken together, Thin Film Processes II and its predecessor present a thorough grounding in modern thin film techniques.Key Features* Provides an all-new sequel to the 1978 classic, Thin Film Processes* Introduces new topics, and sever

  15. Pyrolyzed thin film carbon

    Science.gov (United States)

    Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Harder, Theodore (Inventor); Konishi, Satoshi (Inventor); Miserendino, Scott (Inventor)

    2010-01-01

    A method of making carbon thin films comprises depositing a catalyst on a substrate, depositing a hydrocarbon in contact with the catalyst and pyrolyzing the hydrocarbon. A method of controlling a carbon thin film density comprises etching a cavity into a substrate, depositing a hydrocarbon into the cavity, and pyrolyzing the hydrocarbon while in the cavity to form a carbon thin film. Controlling a carbon thin film density is achieved by changing the volume of the cavity. Methods of making carbon containing patterned structures are also provided. Carbon thin films and carbon containing patterned structures can be used in NEMS, MEMS, liquid chromatography, and sensor devices.

  16. Reproducibility and calibration studies of TLD 600, TLD 700 and TLD 400

    International Nuclear Information System (INIS)

    Cavalieri, T.A.; Castro, V.A.; Siqueira, P.T.D.

    2013-01-01

    A new method to study of reproducibility of the thermoluminescent dosimeters (TLDs) and their calibration was carried on and compared with the method previously used by the BNCT research group of IPEN/CNEN. In this new method, aimed to identify the relations between the individual response of certain types of TLDs with their average response, it was observed a relation approximately constant even at different irradiations. From these relations, normalization of TLDs responses were made, and this method was compared with the method previously adopted by BNCT research group of IPEN/CNEN given better responses. With this new method, the dose response calibration o were made for two gamma sources, with different energies, 60 Co and 137 Cs, for doses ranging from 20 mGy to 1 Gy, and it has been possible to observe the response dependence of these TLDs on energy. (author)

  17. Screen-film mammography

    International Nuclear Information System (INIS)

    Logan, W.W.; Janus, J.A.

    1987-01-01

    The development of screen-film mammography has resulted in the re-emergence of confidence, rather than fear, in mammography. When screen-film mammography is performed with state-of-the-art dedicated equipment utilizing vigorous breast compression and a ''soft'' x-ray beam for improved contrast, screen-film images are equivalent or superior to those of reduced-dose xeromammography and superior to those of nonscreen film mammography. Technological aids for conversion from xeromammographic or nonscreen film mammographic techniques to screen-film techniques have been described. Screen-film mammography should not be attempted until dedicated equipment has been obtained and the importance of vigorous compression has been understood

  18. Ceramic Composite Thin Films

    Science.gov (United States)

    Ruoff, Rodney S. (Inventor); Stankovich, Sasha (Inventor); Dikin, Dmitriy A. (Inventor); Nguyen, SonBinh T. (Inventor)

    2013-01-01

    A ceramic composite thin film or layer includes individual graphene oxide and/or electrically conductive graphene sheets dispersed in a ceramic (e.g. silica) matrix. The thin film or layer can be electrically conductive film or layer depending the amount of graphene sheets present. The composite films or layers are transparent, chemically inert and compatible with both glass and hydrophilic SiOx/silicon substrates. The composite film or layer can be produced by making a suspension of graphene oxide sheet fragments, introducing a silica-precursor or silica to the suspension to form a sol, depositing the sol on a substrate as thin film or layer, at least partially reducing the graphene oxide sheets to conductive graphene sheets, and thermally consolidating the thin film or layer to form a silica matrix in which the graphene oxide and/or graphene sheets are dispersed.

  19. Radiation dose during tomography of the petrous bone. Experimental investigations with film dosimetry on an Alderson phantom

    Energy Technology Data Exchange (ETDEWEB)

    Grehn, S.

    1988-06-01

    Using filmdosimetry and an Alderson skull phantom, the iso-dose distribution during tomography of the petrous bone was investigated. We were particularly concerned with the radiation dose to the lens of the eye, the critical organ in the skull, and to the inner ear, using different types of examination and various positions of the skull. The choice of suitable film material and standardisation against TLD measurements is crucial for the accuracy of film dosimetry, allowing for correction of film blackening in relation to varying energies. Tomography of the petrous bone in the prone position produced a reduction in radiation dose to the eye to only 1 to 4% of the dose incident on the occiput. In this way, and using high definition screen and grinds, it is possible to obtain optimal tomographic images despite drastic reduction of the scattered radiation to the eye. Radiation dose to the inner ear is greatly below any significant somatic dose, irrespective of projection or technique. Special measures to reduce radiation to the inner ear are neither effective nor sensible.

  20. Virtual film technique used in 3d and step-shot IMRT planning check

    International Nuclear Information System (INIS)

    Wang, Y.; Zealey, W.; Deng, X.; Huang, S.; Qi, Z.

    2004-01-01

    Full text: A virtual film technique developed and used in segmented field dose reconstruction for IMRT planning dose distribution check. Film dosimetry analysis is commonly used for the isodose curve comparison but the result can be affected by film dosimetry technical problems, and the film processing also takes a significant amount of workload. This study is focused on using digital image technique to reconstruct dose distribution for a 3D plan by mapping water-scanning data on screen in black and white intensity value, and by simulating the film analysis process to plot equivalent Isodose curve for the planning Isodose comparison check. In-house developed software is used to select the TPR (Tissue-Phantom Ratio) and OCR (Off Central-Axis Ratio) data for different beam field types and sizes; each point dose of the field is interpolated and converted into the greyscale pixel value. The location of the pixel is calculated by the triangular function according to the beam entry position and gantry/collimator angles. After each segment field is processed, the program gathers all the segments and overlays the greyscale value pixel by pixel for all the segments into a combined map. The background value is calibrated to match the water scan curve background level. The penumbra slope is adjusted by an interpolated divergent angle according to the OAD (Off Central-Axis Distance) of the field. A normal film dosimetry analysis can then be performed to plot the Isodose curves. By comparing some typical fields with both single beam and segmented IMRT fields, with the point dose checked by ionization measurement, the central point dose discrepancy is within ±2% and the maximum 3-5% for a random point using TLD technique. Compare the Isodose overlaying result to planning curves for both perpendicular and lateral beam. Although the curve shape for the virtual film viewed is more artificial compared with real film, the results are easier to compare for the quantity analysis with

  1. Film: Genres and Genre Theory

    DEFF Research Database (Denmark)

    Bondebjerg, Ib

    2015-01-01

    Genre is a concept used in film studies and film theory to describe similarities between groups of films based on aesthetic or broader social, institutional, cultural, and psychological aspects. Film genre shares similarities in form and style, theme, and communicative function. A film genre...

  2. Film Music. Factfile No. 8.

    Science.gov (United States)

    Elsas, Diana, Ed.; And Others

    Organizations listed here with descriptive information include film music clubs and music guilds and associations. These are followed by a representative list of schools offering film music and/or film sound courses. Sources are listed for soundtrack recordings, sound effects/production music, films on film music, and oral history programs. The…

  3. Demagnetization in photomagnetic films

    Energy Technology Data Exchange (ETDEWEB)

    Pajerowski, Daniel M., E-mail: daniel@pajerowski.com [NIST Center for Neutron Research, Gaithersburg, Maryland 20899 (United States); Hallock, Scott J. [NIST Center for Neutron Research, Gaithersburg, Maryland 20899 (United States); Winston Churchill High School, Potomac, Maryland 20854 (United States)

    2012-05-15

    We present a model for demagnetization in photomagnetic films, and investigate different regimes for the magnetizing process using finite element analysis. It is found that the demagnetizing factor may depend strongly upon the high-spin fraction of the film, and the specifics of the dependence are dictated by the microscopic morphology of the photomagnetic domains. This picture allows for facile interpretation of existing data on photomagnetic films, and can even explain an observed photoinduced decrease in low-field magnetization concurrent with increase in high-spin fraction. As a whole, these results reiterate the need to consider demagnetizing effects in photomagnetic films. - Highlights: Black-Right-Pointing-Pointer Finite element methods are used to examine demagnetization in photomagnetic films. Black-Right-Pointing-Pointer Under the right conditions, photomagnetic films may show a photoinduced decrease. Black-Right-Pointing-Pointer Demagnetization in photomagnets will be important to consider in possible devices.

  4. Superconducting thin films

    International Nuclear Information System (INIS)

    Hebard, A.F.; Vandenberg, J.M.

    1982-01-01

    This invention relates to granular metal and metal oxide superconducting films formed by ion beam sputter deposition. Illustratively, the films comprise irregularly shaped, randomly oriented, small lead grains interspersed in an insulating lead oxide matrix. The films are hillock-resistant when subjected to thermal cycling and exhibit unusual josephson-type switching characteristics. Depending on the oxygen content, a film may behave in a manner similar to that of a plurality of series connected josephson junctions, or the film may have a voltage difference in a direction parallel to a major surface of the film that is capable of being switched from zero voltage difference to a finite voltage difference in response to a current larger than the critical current

  5. Underwater 3D filming

    Directory of Open Access Journals (Sweden)

    Roberto Rinaldi

    2014-12-01

    Full Text Available After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie’s box offices due to the overall quality of its products. Special environments such as space (“Gravity” and the underwater realm look perfect to be reproduced in 3D. “Filming in space” was possible in “Gravity” using special effects and computer graphic. The underwater realm is still difficult to be handled. Underwater filming in 3D was not that easy and effective as filming in 2D, since not long ago. After almost 3 years of research, a French, Austrian and Italian team realized a perfect tool to film underwater, in 3D, without any constrains. This allows filmmakers to bring the audience deep inside an environment where they most probably will never have the chance to be.

  6. Den danske independent film

    DEFF Research Database (Denmark)

    Hansen, Kim Toft

    2014-01-01

    at producere film, og derved er filmproduktion potentielt gjort tilgængelig for en større gruppe personer som både afsender og modtager. For det fjerde implicerer diskussionen af de to film også genre- og stilmæssige spørgsmål om dansk filmkultur, fordi indiefilmen både i film og uden for filmene italesætter...

  7. Religion og film

    DEFF Research Database (Denmark)

    Hvithamar, Annika; Eskjær, Mikkel Fugl

    2007-01-01

    Artiklen søger at stipulere en ramme for analyse af religion og film. Dels ved at række ud over den blotte konstatering af tilstedeværelse af religiøse elementer i film, dels ved at anslå en række temaer, der kan anvendes til analyse af sådanne film (individualisering, (de-)sekularisering, banal...

  8. Horror films and psychiatry.

    Science.gov (United States)

    Friedman, Susan Hatters; Forcen, Fernando Espi; Shand, John Preston

    2014-10-01

    Horror films have been popular for generations. The purpose of this article is to illustrate psychiatric conditions, themes and practice seen in horror films. Horror films often either include psychiatrists as characters or depict (Hollywood's dangerous version of) serious mental illness. Demonic possession, zombies, and 'slasher' killers are described, as well as the horror genre's characterizations of psychiatrists. © The Royal Australian and New Zealand College of Psychiatrists 2014.

  9. Renaissance of the Film.

    Science.gov (United States)

    Bellone, Julius, Ed.

    The post-World War II period was one of the liveliest in the history of the cinema. This is a collection of 33 critical articles on some of the best films of the perd. Most of the essays explicate the themes and symbols of the films. The essays deal with these films: "The Apu Trilogy,""L'Avventura,""Balthazar,""Blow-Up,""Bonnie and Clyde," Citizen…

  10. Experimental calibration and determination of the relative response for Lif: Mg, Ti(TLD-100) dosemeters at 60Co gamma and 60 kVp X-ray energies

    International Nuclear Information System (INIS)

    Marco, M.L.; Gonzalez, L.; Delgado, V.; Vano, E.; Moran, P.

    1985-01-01

    The thermoluminescence efficiency of LiF: Mg, Ti (TLD-100) dosemeters has been determined for photon beams from 60 Co gamma rays and 60 kVp X-rays. It has been proven that light yield varies as a function of the photon energy. An experiment was performed using an X-ray beam whose spectrum has been determined by an X-ray fluorescence method. This enabled a direct calculation of the absorbed doses in the T1 material for the different operation conditions. These values and the experimental ones from measuring T1 intensities have been used to obtain the efficiency for energy X-ray spectrum. From the above values, the dosemeter T1 response, relative to 60 Co, has been evaluated. (author)

  11. Film in concert

    OpenAIRE

    2017-01-01

    From the very beginning of cinema, music always played an important role in the history of filmmaking. Nonetheless, film music is judged by critics as a kind of low-grade art form. However, the majority of film score composers enjoyed a classical education and composed as well for the silver screen as for the concert hall. Film music also has its roots in the musical era of romanticism. Therefore, symphonic film scores can be regarded as program music in a broader sense. These scores were inf...

  12. Film, Neuroaesthetics, and Empathy

    DEFF Research Database (Denmark)

    Grodal, Torben Kragh; Kramer, Mette

    2014-01-01

    The article analyzes the link between film viewing and human 'ultra-sociality' (Boyd and Richardson 1998), describing how empathy is supported by mirror resonances but also modified by appraisal mechanisms and how emotions are communicated, It further discusses how 'attainment' to film builds...... on mother-child communication and also how film genres of attachment use such attainment, especially by means of close-ups of human faces and shot-reverse shots. Finally it deals with how films boost development of cognitive and emotional intelligence...

  13. The Possibility of Film Criticism.

    Science.gov (United States)

    Poague, Leland; Cadbury, William

    1989-01-01

    Examines the role of critical language in film criticism. Compares and contrasts Monroe Beardsley's philosophy on film aesthetics with the New Criticism. Outlines some of the contributions Beardsley has made to the study of film criticism. (KM)

  14. Thin Film & Deposition Systems (Windows)

    Data.gov (United States)

    Federal Laboratory Consortium — Coating Lab: Contains chambers for growing thin film window coatings. Plasma Applications Coating Lab: Contains chambers for growing thin film window coatings. Solar...

  15. FAA Film Catalog.

    Science.gov (United States)

    Federal Aviation Administration (DOT), Washington, DC.

    Some 75 films from the U.S. Department of Transportation's Federal Aviation Administration are listed in this catalog. Topics dealt with include aerodynamics, airports, aviation history and careers, flying clubs, navigation and weather. Most of the films are 16mm sound and color productions. Filmstrips requiring a 35mm projector and phonograph or…

  16. What Is Film Phenomenology?

    NARCIS (Netherlands)

    Hanich, Julian; Ferencz-Flatz, Christian

    2016-01-01

    In this article Christian Ferencz-Flatz and I try to give an answer to the question what film phenomenology actually is. We proceed in three steps. First, we provide a survey of five different research practices within current film phenomenological writing: We call them excavation, explanation,

  17. Stabilized chromium oxide film

    Science.gov (United States)

    Garwin, Edward L.; Nyaiesh, Ali R.

    1988-01-01

    Stabilized air-oxidized chromium films deposited on high-power klystron ceramic windows and sleeves having a thickness between 20 and 150.ANG. are useful in lowering secondary electron emission yield and in avoiding multipactoring and window failure due to overheating. The ceramic substrate for the film is chosen from alumina, sapphire or beryllium oxide.

  18. On Teaching Ethnographic Film

    Science.gov (United States)

    Clarfield, Geoffrey

    2013-01-01

    The author of this article, a developmental anthropologist, illustrates how the instructor can use ethnographic films to enhance the study of anthropology and override notions about the scope and efficacy of Western intervention in the Third World, provided the instructor places such films in their proper historical and cultural context. He…

  19. Determining Film Art.

    Science.gov (United States)

    Bullis, Roger

    1974-01-01

    The criteria by which films can and should be analyzed as art are discussed in this paper. A triangular model of theme-form-content is presented with form given greater significance than is usually the case in film criticism. The form-content-theme synthesis is the process in which theme is made clear by means of form and content within an…

  20. Thick film hydrogen sensor

    Science.gov (United States)

    Hoffheins, Barbara S.; Lauf, Robert J.

    1995-01-01

    A thick film hydrogen sensor element includes an essentially inert, electrically-insulating substrate having deposited thereon a thick film metallization forming at least two resistors. The metallization is a sintered composition of Pd and a sinterable binder such as glass frit. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors.

  1. "Fate: The short film"

    OpenAIRE

    Maya Quintana, Jennifer

    2014-01-01

    "Fate: The Short Film" is a four minute short film which reflects the idea that nobody can escape from the fate. It has a good picture and sound quality with an understandable message for all public and with the collaboration of actors, filmmaker, stylist, script advisor and media technician.

  2. Malaysian Cinema, Asian Film

    NARCIS (Netherlands)

    Heide, van der William

    2002-01-01

    This title series departs from traditional studies of national cinema by accentuating the intercultural and intertextual links between Malaysian films and Asian (as well as European and American) film practices. Using cross-cultural analysis, the author characterizes Malaysia as a pluralist society

  3. Abstract Film and Beyond.

    Science.gov (United States)

    Le Grice, Malcolm

    A theoretical and historical account of the main preoccupations of makers of abstract films is presented in this book. The book's scope includes discussion of nonrepresentational forms as well as examination of experiments in the manipulation of time in films. The ten chapters discuss the following topics: art and cinematography, the first…

  4. Protolytic carbon film technology

    Energy Technology Data Exchange (ETDEWEB)

    Renschler, C.L.; White, C.A.

    1996-04-01

    This paper presents a technique for the deposition of polyacrylonitrile (PAN) on virtually any surface allowing carbon film formation with only the caveat that the substrate must withstand carbonization temperatures of at least 600 degrees centigrade. The influence of processing conditions upon the structure and properties of the carbonized film is discussed. Electrical conductivity, microstructure, and morphology control are also described.

  5. Selective inorganic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, M.L.F.; Weisenbach, L.A.; Anderson, M.T. [Sandia National Laboratories, Albuquerque, NM (United States)] [and others

    1995-05-01

    This project is developing inorganic thin films as membranes for gas separation applications, and as discriminating coatings for liquid-phase chemical sensors. Our goal is to synthesize these coatings with tailored porosity and surface chemistry on porous substrates and on acoustic and optical sensors. Molecular sieve films offer the possibility of performing separations involving hydrogen, air, and natural gas constituents at elevated temperatures with very high separation factors. We are focusing on improving permeability and molecular sieve properties of crystalline zeolitic membranes made by hydrothermally reacting layered multicomponent sol-gel films deposited on mesoporous substrates. We also used acoustic plate mode (APM) oscillator and surface plasmon resonance (SPR) sensor elements as substrates for sol-gel films, and have both used these modified sensors to determine physical properties of the films and have determined the sensitivity and selectivity of these sensors to aqueous chemical species.

  6. Conceiving Landscape through Film

    DEFF Research Database (Denmark)

    Farsø, Mads; Munck Petersen, Rikke

    2015-01-01

    This article shows how the media of film can be integrated, explored and can add value to architectural design studios and practice. It elucidates how film may offer an alternative position in architecture, where landscapes and cities are thought, planned and developed in closer relation...... to their spatial and sensory effects on humans. It underscores that the film camera can work as a kind of amplifier of how we, with our bodies, perceive space and project space. In the “Landscape Film” Studio at University of Copenhagen the film medium was tested as a combined registration and design tool...... for a new Nature Park south of Copenhagen. The final studio films and designs show how resonate recordings of sound, time and a bodily presence may simulate an Einfühling that inspires an alternative architecture of relations: the ambient, the changeable and the volatile. They also emphasize that an ability...

  7. Film sheet cassette

    International Nuclear Information System (INIS)

    1981-01-01

    A novel film sheet cassette is described for handling CAT photographic films under daylight conditions and facilitating their imaging. A detailed description of the design and operation of the cassette is given together with appropriate illustrations. The resulting cassette is a low-cost unit which is easily constructed and yet provides a sure light-tight seal for the interior contents of the cassette. The individual resilient fingers on the light-trap permit the ready removal of the slide plate for taking pictures. The stippled, non-electrostatic surface of the pressure plate ensures an air layer and free slidability of the film for removal and withdrawal of the film sheet. The advantage of the daylight system is that a darkroom need not be used for inserting and removing the film in and out of the cassette resulting in a considerable time saving. (U.K.)

  8. IAEA film library

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1959-01-15

    Most of the scientific and technical films shown during the Second Geneva Conference for the Peaceful Uses of Atomic Energy were donated to IAEA by the producing countries at the end of the Conference. They will form the basic stock for the Agency's loan service intended to provide atomic energy institutions in Member States with film material. A detailed catalogue of the films, classified according to subject and giving conditions of loan or purchase, is now being prepared. In addition to this, information on all films produced in Member Countries dealing with the peaceful uses cf atomic energy is being assembled. The documentary information contained in the films in IAEA's possession relates to the following subjects: national programmes; nuclear physics; accelerators; plasma and fusion; reactors (power, research, material testing and experimental); prospecting and mining; ore dressing; metallurgy; production of fuel elements; treatment of irradiated fuel elements; protection against radiation; detection and counting; uses of radiation in medicine, biochemistry, agriculture and industry; industrial application of nuclear explosions. Most of the commentaries are in the language of the producing country. A few films are available in a choice of two languages. The films donated to the Agency total 82, two of which have been produced in Canada, 13 in France, one in India, one in Romania, one in Spain, 14 in the United Kingdom, one in the Union of South Africa, 47 in the United States of America and two in the USSR: they are mostly illustrations of papers presented at the Second Geneva Conference. In arranging for the circulation of scientific and technical films IAEA wishes to help meet some of the training and information needs of Member States. It is hoped that all organizations producing films on the peaceful uses of atomic energy will entrust copies to the IAEA with a view to their widest possible circulation. In the meantime, the Agency's films have been given

  9. IAEA film library

    International Nuclear Information System (INIS)

    1959-01-01

    Most of the scientific and technical films shown during the Second Geneva Conference for the Peaceful Uses of Atomic Energy were donated to IAEA by the producing countries at the end of the Conference. They will form the basic stock for the Agency's loan service intended to provide atomic energy institutions in Member States with film material. A detailed catalogue of the films, classified according to subject and giving conditions of loan or purchase, is now being prepared. In addition to this, information on all films produced in Member Countries dealing with the peaceful uses cf atomic energy is being assembled. The documentary information contained in the films in IAEA's possession relates to the following subjects: national programmes; nuclear physics; accelerators; plasma and fusion; reactors (power, research, material testing and experimental); prospecting and mining; ore dressing; metallurgy; production of fuel elements; treatment of irradiated fuel elements; protection against radiation; detection and counting; uses of radiation in medicine, biochemistry, agriculture and industry; industrial application of nuclear explosions. Most of the commentaries are in the language of the producing country. A few films are available in a choice of two languages. The films donated to the Agency total 82, two of which have been produced in Canada, 13 in France, one in India, one in Romania, one in Spain, 14 in the United Kingdom, one in the Union of South Africa, 47 in the United States of America and two in the USSR: they are mostly illustrations of papers presented at the Second Geneva Conference. In arranging for the circulation of scientific and technical films IAEA wishes to help meet some of the training and information needs of Member States. It is hoped that all organizations producing films on the peaceful uses of atomic energy will entrust copies to the IAEA with a view to their widest possible circulation. In the meantime, the Agency's films have been given

  10. Films Deliver: Teaching Creatively with Film.

    Science.gov (United States)

    Schillaci, Anthony, Ed.; Culkin, John M., Ed.

    The fifteen papers in this resource guide are grouped into four sections. Section one contains formulations of the basic rationale for screen education and descriptions of new concepts and approaches to film study. Section two presents a definition of the elements involved in filmmaking and viewing, and it describes several model programs which…

  11. Process and apparatus for irradiating film, and irradiated film

    International Nuclear Information System (INIS)

    1981-01-01

    A process for irradiating film is described, which consists of passing the film through an electron irradiation zone having an electron reflection surface disposed behind and generally parallel to the film; and disposing within the irradiation zone adjacent the edges of the film a lateral reflection member for reflecting the electrons toward the reflection surface to further reflect the reflected electrons towards the adjacent edges of the film. (author)

  12. Biomimetic thin film synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Graff, G.L.; Campbell, A.A.; Gordon, N.R.

    1995-05-01

    The purpose of this program is to develop a new process for forming thin film coatings and to demonstrate that the biomimetic thin film technology developed at PNL is useful for industrial applications. In the biomimetic process, mineral deposition from aqueous solution is controlled by organic functional groups attached to the underlying substrate surface. The coatings process is simple, benign, inexpensive, energy efficient, and particularly suited for temperature sensitive substrate materials (such as polymers). In addition, biomimetic thin films can be deposited uniformly on complex shaped and porous substrates providing a unique capability over more traditional line-of-sight methods.

  13. Intermetallic semiconducting films

    CERN Document Server

    Wieder, H H

    1970-01-01

    Intermetallic Semiconducting Films introduces the physics and technology of AшВv compound films. This material is a type of a polycrystalline semiconductor that is used for galvanomagnetic device applications. Such material has a high electron mobility that is ideal for generators and magnetoresistors. The book discusses the available references on the preparation and identification of the material. An assessment of its device applications and other possible use is also enumerated. The book describes the structures and physical parts of different films. A section of the book covers the three t

  14. X-ray film

    International Nuclear Information System (INIS)

    Arndt, U.W.; Gilmore, D.J.; Wonacott, A.J.

    1977-01-01

    The performance of film as an X-ray detector is discussed and its behaviour is compared with that of a perfect Poissonian detector. The efficiency of microdensitometry as a method of extracting the information recorded on the film is discussed. More emphasis is placed in the precision of microdensitometric measurements than on the more obvious characteristic of film speed. The effects of chemical fog and background on the precision of the measurements is considered and it is concluded that the final limit to precision is set by the chemical fog. (B.D.)

  15. Ultrahard carbon nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    Siegal, M. P. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States); Tallant, D. R. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States); Provencio, P. N. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States); Overmyer, D. L. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States); Simpson, R. L. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States); Martinez-Miranda, L. J. [Department of Materials and Nuclear Engineering, University of Maryland, College Park, Maryland 20742 (United States)

    2000-05-22

    Modest thermal annealing to 600 degree sign C of diamondlike amorphous-carbon (a-C) films grown at room temperature results in the formation of carbon nanocomposites with hardness similar to diamond. These nanocomposite films consist of nanometer-sized regions of high density a-C embedded in an a-C matrix with a reduced density of 5%-10%. We report on the evolution of density and bonding topologies as a function of annealing temperature. Despite a decrease in density, film hardness actually increases {approx}15% due to the development of the nanocomposite structure. (c) 2000 American Institute of Physics.

  16. Ultrahard carbon nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    SIEGAL,MICHAEL P.; TALLANT,DAVID R.; PROVENCIO,PAULA P.; OVERMYER,DONALD L.; SIMPSON,REGINA L.; MARTINEZ-MIRANDA,L.J.

    2000-01-27

    Modest thermal annealing to 600 C of diamondlike amorphous-carbon (a-C) films grown at room temperature results in the formation of carbon nanocomposites with hardness similar to diamond. These nanocomposite films consist of nanometer-sized regions of high density a-C embedded in an a-C matrix with a reduced density of 5--10%. The authors report on the evolution of density and bonding topologies as a function of annealing temperature. Despite a decrease in density, film hardness actually increases {approximately} 15% due to the development of the nanocomposite structure.

  17. FEMINIST FILM THEORY

    OpenAIRE

    Wijaya, Haris

    2015-01-01

    The developing of film industry has brought us into a complexity of art and business. If the first movie audiences were delighted to see that it was possible to record a moving scene on film; today we debate the desirability behind every movie, rather than just the possibility of capturing an image. Film has already become entertainment tool and communication media with quite powerful effect to influence people at the early 20th century. The problem that happens now is there are not many wome...

  18. Nopal cactus film

    Science.gov (United States)

    Toxqui-López, S.; Olivares-Pérez, A.; Fuentes-Tapia, I.; Conde-Cuatzo, María. G.

    2017-03-01

    Nopal mucilage potentially has certain properties required for the preparation biofilms which can be used as holographic replication recording medium. In this study, mucilage from nopal was extracted and characterized by its ability to form films under different concentration with polyvinyl alcohol. The transmission holographic diffraction gratings (master) were replicated into nopal films. The results showed good diffraction efficiencies. Mucilage from nopal could represent a good option for the development of films to replication holographic, owing to; its low cost and its compatibility with the environmental.

  19. Underwater 3D filming

    OpenAIRE

    Rinaldi, Roberto

    2014-01-01

    After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie’s box offices due to the overall quality of its products. Special environments such as space (“Gravity” ) and the underwater realm look perfect to be reproduced in 3D. “Filming in space” was possible in “Gravity” using special effects and computer graphic. The underwater realm is still difficult to be handled. Unde...

  20. Radiographic film digitizing devices

    International Nuclear Information System (INIS)

    McFee, W.H.

    1988-01-01

    Until recently, all film digitizing devices for use with teleradiology or picture archiving and communication systems used a video camera to capture an image of the radiograph for subsequent digitization. The development of film digitizers that use a laser beam to scan the film represents a significant advancement in digital technology, resulting in improved image quality compared with video scanners. This paper discusses differences in resolution, efficiency, reliability, and the cost between these two types of devices. The results of a modified receiver operating characteristic comparison study of a video scanner and a laser scanner manufactured by the same company are also discussed

  1. Film Scriptwriting: A Practical Manual.

    Science.gov (United States)

    Swain, Dwight V.

    Dealing with both documentary and feature films, this book is a guide to using particular tools and procedures in developing ideas and concepts for writing film scripts. Part one deals with the factual, or documentary, film and discusses the proposal outline, film treatment, sequence outline, shooting script, and narration writing. Part two…

  2. Discovery in Film, Book Two.

    Science.gov (United States)

    Gordon, Malcolm W.

    Approximately 80 16 millimeter (16mm) short films are reviewed in this introduction and guide which attempts to be comprehensive in touching the major areas and styles of 16mm films now being produced. An attempt is made to describe as carefully as possible the style and content of each film and suggest ways in which the films might be used. Films…

  3. Thin films for precision optics

    International Nuclear Information System (INIS)

    Araujo, J.F.; Maurici, N.; Castro, J.C. de

    1983-01-01

    The technology of producing dielectric and/or metallic thin films for high precision optical components is discussed. Computer programs were developed in order to calculate and register, graphically, reflectance and transmittance spectra of multi-layer films. The technology of vacuum evaporation of several materials was implemented in our thin-films laboratory; various films for optics were then developed. The possibility of first calculate film characteristics and then produce the film is of great advantage since it reduces the time required to produce a new type of film and also reduces the cost of the project. (C.L.B.) [pt

  4. Film and Visual Perception

    Science.gov (United States)

    Giltrow, David

    1978-01-01

    One practical method which development film makers can adopt to increase comprehension of important scenes is to eliminate extraneous background information by putting it out of focus, or by shooting against plain backgrounds. (Author/STS)

  5. Film documentaire, lecture documentarisante

    Directory of Open Access Journals (Sweden)

    Roger Odin

    2012-06-01

    Full Text Available Réfléchir sur la relation entre le cinéma et la réalité n’est pas, bien sûr, tenter de distinguer l’espace du documentaire de celui de la fiction, au point que l’opposition avec le film de fiction est devenu le critère de définition privilégié du film documentaire. Prenant acte l’existence, dans le espace de la lecture des films, d’une lecture documentaire ou, plus exactement, d’une lecture documentarisante, nous pensons qu’il y a un ensemble de films que s’affiche comme documentaire (tout le problème est précisément étudier comment s’effetue cet affichage.

  6. Fra bog til film

    DEFF Research Database (Denmark)

    Schepelern, Peter

    2010-01-01

    Efter en historisk oversigt over samspillet mellem film og litteratur i dansk film, opstilles en råkke begreber, som filmatiseringer kan analyseres ud fra. Der ses pa det litteråre vårks status — evt. som klassiker eller bestseller. Der ses pa de centrale filmatiseringsproblemer, forhold som pråger...... adaptionsprocessen fra bog til film. De kan opdeles dels i forhold, der udspringer af filmsprogets specifikke sys- tem, dels forhold, der udspringer af filmens status som massemedium. Den färste kategori er pråget af, at filmsproget generelt fremstiller handling snarere end refleksion, noget konkret snarere end...... noget abstrakt, en scene snarere end et resume og det ydre snarere det indre. Den anden kategori kan forklare filmens tilbäjelighed til åndring af forlågget, til forkortelse, forenkling og modernisering. Eksemplerne er en råkke centrale danske film/romaner...

  7. Thin Film Microbatteries

    International Nuclear Information System (INIS)

    Dudney, Nancy J.

    2008-01-01

    Thin film batteries are built layer by layer by vapor deposition. The resulting battery is formed of parallel plates, much as an ordinary battery construction, just much thinner. The figure (Fig. 1) shows an example of a thin film battery layout where films are deposited symmetrically onto both sides of a supporting substrate. The full stack of films is only 10 to 15 (micro)m thick, but including the support at least doubles the overall battery thickness. When the support is thin, the entire battery can be flexible. At least six companies have commercialized or are very close to commercializing such all-solid-state thin film batteries and market research predicts a growing market and a variety of applications including sensors, RFID tags, and smarter cards. In principle with a large deposition system, a thin film battery might cover a square meter, but in practice, most development is targeting individual cells with active areas less than 25 cm 2 . For very small battery areas, 2 , microfabrication processes have been developed. Typically the assembled batteries have capacities from 0.1 to 5 mAh. The operation of a thin film battery is depicted in the schematic diagram (Fig. 2). Very simply, when the battery is allowed to discharge, a Li + ion migrates from the anode to the cathode film by diffusing through the solid electrolyte. When the anode and cathode reactions are reversible, as for an intercalation compound or alloy, the battery can be recharged by reversing the current. The difference in the electrochemical potential of the lithium determines the cell voltage. Most of the thin films used in current commercial variations of this thin film battery are deposited in vacuum chambers by RF and DC magnetron sputtering and by thermal evaporation onto unheated substrates. In addition, many publications report exploring a variety of other physical and chemical vapor deposition processes, such as pulsed laser deposition, electron cyclotron resonance sputtering, and

  8. Thin film device applications

    CERN Document Server

    Kaur, Inderjeet

    1983-01-01

    Two-dimensional materials created ab initio by the process of condensation of atoms, molecules, or ions, called thin films, have unique properties significantly different from the corresponding bulk materials as a result of their physical dimensions, geometry, nonequilibrium microstructure, and metallurgy. Further, these characteristic features of thin films can be drasti­ cally modified and tailored to obtain the desired and required physical characteristics. These features form the basis of development of a host of extraordinary active and passive thin film device applications in the last two decades. On the one extreme, these applications are in the submicron dimensions in such areas as very large scale integration (VLSI), Josephson junction quantum interference devices, magnetic bubbles, and integrated optics. On the other extreme, large-area thin films are being used as selective coatings for solar thermal conversion, solar cells for photovoltaic conver­ sion, and protection and passivating layers. Ind...

  9. Quantitative film radiography

    International Nuclear Information System (INIS)

    Devine, G.; Dobie, D.; Fugina, J.; Hernandez, J.; Logan, C.; Mohr, P.; Moss, R.; Schumacher, B.; Updike, E.; Weirup, D.

    1991-01-01

    We have developed a system of quantitative radiography in order to produce quantitative images displaying homogeneity of parts. The materials that we characterize are synthetic composites and may contain important subtle density variations not discernible by examining a raw film x-radiograph. In order to quantitatively interpret film radiographs, it is necessary to digitize, interpret, and display the images. Our integrated system of quantitative radiography displays accurate, high-resolution pseudo-color images in units of density. We characterize approximately 10,000 parts per year in hundreds of different configurations and compositions with this system. This report discusses: the method; film processor monitoring and control; verifying film and processor performance; and correction of scatter effects

  10. Min Morfars Film

    DEFF Research Database (Denmark)

    Juel, Henrik

    1957-01-01

    Reflektioner over filmhistoriebegrebet og gennemgang af konkrete filmoplevelser i 1957 og i nutiden med udgangspunkt i mødet med en gammel familiefilm. Reflektioner over valg af motiver i en social- og personhistorisk dateret film.......Reflektioner over filmhistoriebegrebet og gennemgang af konkrete filmoplevelser i 1957 og i nutiden med udgangspunkt i mødet med en gammel familiefilm. Reflektioner over valg af motiver i en social- og personhistorisk dateret film....

  11. Architecture and Film

    OpenAIRE

    Mohammad Javaheri, Saharnaz

    2016-01-01

    Film does not exist without architecture. In every movie that has ever been made throughout history, the cinematic image of architecture is embedded within the picture. Throughout my studies and research, I began to see that there is no director who can consciously or unconsciously deny the use of architectural elements in his or her movies. Architecture offers a strong profile to distinguish characters and story. In the early days, films were shot in streets surrounde...

  12. Anthropology of Film

    Directory of Open Access Journals (Sweden)

    Ivan Kovačević

    2017-08-01

    Full Text Available The second volume of the journal in 2017, which is part of the thematic issue, includes foreign films, and five of the eight papers contribute analyses of dystopian films. These are: A Clockwork Orange (1971, Westworld (1973, Gattaca (1997 The Lobster (2015 and Man and Chicken (2015. Aside from this thematic block, the first part of the thematic issue comprises the analyses of Miracolo a Milano (1951, Happiness (1998 and American Gangster (2007.

  13. Isodose curves through films

    International Nuclear Information System (INIS)

    Moura, A.M.S.; Campos, J.C.F. de; Scaff, L.A.M.; Val Kopacek, A.B. do

    1985-01-01

    Information about the beam profile of 4 MV X-rays through irradiation of radiographic films is presented. The films were irradiated in parallel to the central axis, within tissue-like phantom and in conditions of clinical application. The conclusion is that the method does not supply absolute values of percentage depth dose over points outside of beam bounds, but throughout the corrections it may be of great utility in radiation dosimetry. (Author) [pt

  14. Isodose curves through films

    Energy Technology Data Exchange (ETDEWEB)

    Moura, A.M.S.; Campos, J.C.F. de; Scaff, L.A.M.; Val Kopacek, A.B. do

    Information about the beam profile of 4 MV X-rays through irradiation of radiographic films is presented. The films were irradiated in parallel to the central axis, within tissue-like phantom and in conditions of clinical application. The conclusion is that the method does not supply absolute values of percentage depth dose over points outside of beam bounds, but throughout the corrections it may be of great utility in radiation dosimetry. (Author).

  15. Thin film tritium dosimetry

    Science.gov (United States)

    Moran, Paul R.

    1976-01-01

    The present invention provides a method for tritium dosimetry. A dosimeter comprising a thin film of a material having relatively sensitive RITAC-RITAP dosimetry properties is exposed to radiation from tritium, and after the dosimeter has been removed from the source of the radiation, the low energy electron dose deposited in the thin film is determined by radiation-induced, thermally-activated polarization dosimetry techniques.

  16. Innovative polyimide film

    International Nuclear Information System (INIS)

    Yaro, L.

    1988-01-01

    This paper reports on a new type of polyimide film with a unique chemical structure. Developed using proprietary technology, Upilex features outstanding properties over a wide range of temperatures, and offers the following advantages over previously available polyimide film: ultra-high heat resistance, excellent cryogenic properties, high tensile strength and modulus, excellent radiation resistance, excellent weather resistance (ultraviolet), superior dimensional stability, excellent chemical resistance, low water absorption, and low gas permeability

  17. Equilibrium helium film in the thick film limit

    International Nuclear Information System (INIS)

    Klier, J.; Schletterer, F.; Leiderer, P.; Shikin, V.

    2003-01-01

    For the thickness of a liquid or solid quantum film, like liquid helium or solid hydrogen, there exist still open questions about how the film thickness develops in certain limits. One of these is the thick film limit, i.e., the crossover from the thick film to bulk. We have performed measurements in this range using the surface plasmon resonance technique and an evaporated Ag film deposited on glass as substrate. The thickness of the adsorbed helium film is varied by changing the distance h of the bulk reservoir to the surface of the substrate. In the limiting case, when h > 0, the film thickness approaches about 100 nm following the van der Waals law in the retarded regime. The film thickness and its dependence on h is precisely determined and theoretically modeled. The equilibrium film thickness behaviour is discussed in detail. The agreement between theory and experiment is very good

  18. Comparison of film dosimetry and Monte Carlo simulations in small field IMRT

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.R.; Suh, T.S.; Choe, B.Y.; Lee, H.K. [The Catholic Univ., Seoul (Korea, Republic of); Sohn. Jason W. [Washington Univ., St. Louis (United States)

    2002-07-01

    Intensity modulated radiation therapy(IMRT) is a recent useful technique that conforms a high dose to the target volume while restricting dose to the surrounding critical organs. In IMRT, the small size beam let is used for intensity modulation. Thus, dose calculation in small field is very important. But, dose calculation in small field is not accurate in recent RTP system because electronic disequilibrium and the effect of multiple scattering electron are not considered in dose calculation. and therefore, We have evaluated the errors of depth dose and beam profile between measurement data and Monte Carlo simulation. With a homogeneous phantom and two heterogeneous phantoms, A thermoluminescent dosimeter (TLD) and radiochromic films have been selected for dose measurement in 6 MV photon beams. A linear accelerator Varian 2300C (Varian Medical Systems, USA) equipped with a multileaf collimator have been used in dose measurement. The results of simulations using the Monte Carlo systems BEAM/EGS4 (NRC, Canada) to model the beam geometry have been compared with dose measurements. Generally good agreements were found between measurements and dose calculations of Monte Carlo simulation. But some discrepancies were found in this study. Thus further study will be needed to compensate these errors.

  19. Radiochromic film dosimetry

    International Nuclear Information System (INIS)

    Soares, Christopher G.

    2006-01-01

    The object of this paper is to give a new user some practical information on the use of radiochromic films for medical applications. While various aspects of radiochromic film dosimetry for medical applications have been covered in some detail in several other excellent review articles which have appeared in the last few years [Niroomand-Rad, A., Blackwell, C.R., Coursey, B.M., Gall, K.P., McLaughlin, W.L., Meigooni, A.S., Nath, R., Rodgers, J.E., Soares, C.G., 1998. Radiochromic dosimetry: recommendations of the AAPM Radiation Therapy Committee Task Group 55. Med. Phys. 25, 2093-2115; Dempsey, J.F., Low, D.A., Mutic, S., Markman, J., Kirov, A.S., Nussbaum, G.H., Williamson, J.F., 2000. Validation of a precision radiochromic film dosimetry system for quantitative two-dimensional imaging of acute exposure dose distributions. Med. Phys. 27, 2462-2475; Butson, M.J., Yu, P.K.N., Cheung, T., Metcalfe, P., 2003. Radiochromic film for medical radiation dosimetry. Mater. Sci. Eng. R41, 61-120], it is the intent of the present author to present material from a more user-oriented and practical standpoint. That is, how the films work will be stressed much less than how to make the films work well. The strength of radiochromic films is most evident in applications where there is a very high dose gradient and relatively high absorbed dose rates. These conditions are associated with brachytherapy applications, measurement of small fields, and at the edges (penumbra regions) of larger fields

  20. Energy dependence of the supralinearity (f(D)max) of peaks 7 and 8 in the high temperature thermoluminescence of LiF:Mg,Ti (TLD-100) : Interpretation using the Unified Interaction Model

    International Nuclear Information System (INIS)

    Datz, H.; Horowitz, Y.S.; Epstein, L.; Oster, L.; Livingstone, J.; Horowitz, A.; Kol, M.; Margaliot, M.

    2011-01-01

    It is demonstrated that the supralinearity of the dose response of glow peaks 7, 8 in the glow curve of LiF:Mg,Ti (TLD-100) are very strongly dependent on photon/electron energy. Previously published data on f(D) max at photon energies of 1.25 MeV, 100 keV and 8.1 keV effective energy coupled with new data at ∼ 540 keV using 90 Sr/ 90 Y beta rays reveals that the maximum supralinearity f(D) max decreases from values of ∼200 and ∼30 at 1.25 MeV, through intermediate values at 540 keV and 100 keV, to values of ∼ 30 and ∼3 at 8.1 keV effective energy. The normalized dose response f(D) for all energies is modeled using the Unified Interaction Model and the dependence of f(D) max on energy is interpreted as arising from strong dependence of the relative intensity of localized recombination on particle energy (ionization density).

  1. Thin films and nanomaterials

    International Nuclear Information System (INIS)

    Jayakumar, S.; Kannan, M.D.; Prasanna, S.

    2012-01-01

    The objective of this book is to disseminate the most recent research in Thin Films, Nanomaterials, Corrosion and Metallurgy presented at the International Conference on Advanced Materials (ICAM 2011) held in PSG College of Technology, Coimbatore, India during 12-16 December 2011. The book is a compilation of 113 chapters written by active researchers providing information and critical insights into the recent advancements that have taken place. Important new applications are possible today in the fields of microelectronics, opto-electronics, metallurgy and energy by the application of thin films on solid surfaces. Recent progress in high vacuum technology and new materials has a remarkable effect in thin film quality and cost. This has led to the development of new single or multi-layered thin film devices with diverse applications in a multitude of production areas, such as optics, thermal barrier coatings and wear protections, enhancing service life of tools and to protect materials against thermal and atmospheric influence. On the other hand, thin film process techniques and research are strongly related to the basic research activities in nano technology, an increasingly important field with countless opportunities for applications due to the emergence of new properties at the nanoscale level. Materials and structures that are designed and fabricated at the nano scale level, offer the potential to produce new devices and processes that may enhance efficiencies and reduce costs in many areas, as photovoltaic systems, hydrogen storage, fuel cells and solar thermal systems. In the book, the contributed papers are classified under two sections i) thin films and ii) nanomaterials. The thin film section includes single or multi layer conducting, insulating or semiconducting films synthesized by a wide variety of physical or chemical techniques and characterized or analyzed for different applications. The nanomaterials section deals with novel or exciting materials

  2. Film beyond boundaries: film, migrant narratives and other media

    OpenAIRE

    Anelise Reich Corseuil

    2006-01-01

    The articles here presented are representative of the debates about the various transformational aspects of film studies, fostering the discussion about the transformations and interactions between national and international narrative forms, the interrelations between film and literature, and film with other media. The critical perspectives here presented range from an emphasis on cultural materialism, dialogism, reception theory, deconstructionism, narrative studies to film aesthetics or fil...

  3. Filming eugenics: teaching the history of eugenics through film.

    Science.gov (United States)

    Ooten, Melissa; Trembanis, Sarah

    2007-01-01

    In teaching eugenics to undergraduate students and general public audiences, film should he considered as a provocative and fruitful medium that can generate important discussions about the intersections among eugenics, gender, class, race, and sexuality. This paper considers the use of two films, A Bill of Divorcement and The Lynchburg Story, as pedagogical tools for the history of eugenics. The authors provide background information on the films and suggestions for using the films to foster an active engagement with the historical eugenics movement.

  4. Gammel Sherlock Holmes-film fundet - igen

    DEFF Research Database (Denmark)

    Lauridsen, Palle Schantz

    2017-01-01

    Om genfunden af en forsvundet Sherlock Holmes-film fra 1911, produceret af Nordisk Films Kompagni......Om genfunden af en forsvundet Sherlock Holmes-film fra 1911, produceret af Nordisk Films Kompagni...

  5. Film Propaganda: Ikonografi Kekuasaan

    Directory of Open Access Journals (Sweden)

    Budi Irawanto

    2004-07-01

    Full Text Available As a modern technological invention cinema has numerous potentialities such as economic, social and political power. Fascist regimes as well as film corporations have employed cinema as a tool of propaganda to control and mobilize the masses for the sake of their power longevity. Moreover, the character of film itself is a perfect fascist medium which came from the network of proto-fascism of the twentieth century civilization. By using various genres of Indonesian cinema from different eras as a case study, this article argues that Indonesian propaganda films have monolithic representation which can be described as a cult of "bapakisme" (patronism, "kultur komando" (command culture, marginalisation of women' role in Indonesian revolutionary movement and demonization of progressive women organisation, and glorification of the role of Soeharto in Indonesian revolutionary movement.

  6. Influence of film dimensions on film droplet formation.

    Science.gov (United States)

    Holmgren, Helene; Ljungström, Evert

    2012-02-01

    Aerosol particles may be generated from rupturing liquid films through a droplet formation mechanism. The present work was undertaken with the aim to throw some light on the influence of film dimensions on droplet formation with possible consequences for exhaled breath aerosol formation. The film droplet formation process was mimicked by using a purpose-built device, where fluid films were spanned across holes of known diameters. As the films burst, droplets were formed and the number and size distributions of the resulting droplets were determined. No general relation could be found between hole diameter and the number of droplets generated per unit surface area of fluid film. Averaged over all film sizes, a higher surface tension yielded higher concentrations of droplets. Surface tension did not influence the resulting droplet diameter, but it was found that smaller films generated smaller droplets. This study shows that small fluid films generate droplets as efficiently as large films, and that droplets may well be generated from films with diameters below 1 mm. This has implications for the formation of film droplets from reopening of closed airways because human terminal bronchioles are of similar dimensions. Thus, the results provide support for the earlier proposed mechanism where reopening of closed airways is one origin of exhaled particles.

  7. Buy, Borrow, or Steal? Film Access for Film Studies Students

    Science.gov (United States)

    Rodgers, Wendy

    2018-01-01

    Libraries offer a mix of options to serve the film studies curriculum: streaming video, DVDs on Reserve, and streaming DVDs through online classrooms. Some professors screen films and lend DVDs to students. But how do students obtain the films required for their courses? How would they prefer to do so? These are among the questions explored using…

  8. Radiographic film cassette unloading apparatus

    International Nuclear Information System (INIS)

    Stievenart, E.F.; Plessers, H.S.; Neujens, G.J.

    1980-01-01

    Apparatus for unloading cassettes, containing exposed radiographic films, has means for unfastening the cassettes, an inclined pathway for gravity feeding and rotating feed members (rollers or belts) to propel the films into the processor. (UK)

  9. Partnervalg på film

    DEFF Research Database (Denmark)

    Kramer, Mette

    2006-01-01

    Nye kognitions- og evolutionspsykologiske aspekter på kvinders filmpræferencer for romantiske film og melodramer......Nye kognitions- og evolutionspsykologiske aspekter på kvinders filmpræferencer for romantiske film og melodramer...

  10. Thin film metal-oxides

    CERN Document Server

    Ramanathan, Shriram

    2009-01-01

    Presents an account of the fundamental structure-property relations in oxide thin films. This title discusses the functional properties of thin film oxides in the context of applications in the electronics and renewable energy technologies.

  11. Optical thin film deposition

    International Nuclear Information System (INIS)

    Macleod, H.A.

    1979-01-01

    The potential usefulness in the production of optical thin-film coatings of some of the processes for thin film deposition which can be classified under the heading of ion-assisted techniques is examined. Thermal evaporation is the process which is virtually universally used for this purpose and which has been developed to a stage where performance is in almost all respects high. Areas where further improvements would be of value, and the possibility that ion-assisted deposition might lead to such improvements, are discussed. (author)

  12. Thin Film Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Zweibel, K.

    1998-11-19

    The motivation to develop thin film technologies dates back to the inception of photovoltaics. It is an idea based on achieving truly low-cost photovoltaics appropriate for mass production and energy significant markets. The key to the idea is the use of pennies worth of active materials. Since sunlight carries relatively little energy in comparison with combustion-based energy sources, photovoltaic (PV) modules must be cheap to produce energy that can be competitive. Thin films are presumed to be the answer to that low-cost requirement. But how cheap do they have to be? The following is an oversimplified analysis that allows some insight into this question.

  13. Oxidation films morphology

    International Nuclear Information System (INIS)

    Paidassi, J.

    1960-01-01

    After studying the oxidation of several pure polyvalent metals (Fe, Cu, Mn, Ni, U) and of their oxides at high temperature and atmospheric pressure, the author suggests how to modify the usual representation of the oxide film (a piling of different oxide layers, homogeneous on a micrographic scale with a equi-axial crystallisation, free of mechanical tensions, with flat boundary surfaces) to have it nearer to reality. In this first part, the author exposes the study of the real micrographic structure of the oxidation film and gives examples of precipitation in the oxides during the cooling of the oxidised sample. (author) [fr

  14. Films and nursing education

    Directory of Open Access Journals (Sweden)

    María GABRIELA FELIPPA

    2016-01-01

    Full Text Available The purpose of this paper is to provide some ideas about the importance of film, with it’s audiovisual narrative, in the nursing education. The use of films during teaching gives the posibility to increase the construction of a professional view.The nursing carreer of Isalud University of Argentina is founded a sistematic work with cinematographic support. In this case are presented different ways of work with cinematographic support in a curricular space of Fundamentals of Nursing of the career of a professional Nurse of the Isalud University.

  15. Superconducting Electronic Film Structures

    Science.gov (United States)

    1991-02-14

    Segmuller, A., Cooper, E.I., Chisholm, M.F., Gupta, A. Shinde, S., and Laibowitz, R.B. Lanthanum gallate substrates for epitaxial high-T superconducting thin...M. F. Chisholm, A. Gupta, S. Shinde, and R. B. Laibowitz, " Lanthanum Gallate Substrates for Epitaxial High-T c Superconducting Thin Films," Appl...G. Forrester and J. Talvacchio, " Lanthanum Copper Oxide Buffer Layers for Growth of High-T c Superconductor Films," Disclosure No. RDS 90-065, filed

  16. Storyboarding an Animated Film

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth

    2009-01-01

    This paper applies notions of transformation to the analysis of data on semiotic processes related to making an animated film. The data derives from a study conducted in an upper secondary school in Copenhagen with students (18 years old) participating in a week-long workshop. The paper applies...... the concept of transduction with a focus on film storyboards: how students transform ideas when working with different modes (audio, visual) of representation. Data includes discourse analysis of semiotic processes and texts, referring to Social Semiotics and the methodology of Mediated Discourse Analysis...

  17. Intellectual Video Filming

    DEFF Research Database (Denmark)

    Juel, Henrik

    in favour of worthy causes. However, it is also very rewarding to draw on the creativity, enthusiasm and rapidly improving technical skills of young students, and to guide them to use video equipment themselves for documentary, for philosophical film essays and intellectual debate. In the digital era......Like everyone else university students of the humanities are quite used to watching Hollywood productions and professional TV. It requires some didactic effort to redirect their eyes and ears away from the conventional mainstream style and on to new and challenging ways of using the film media...

  18. Superconducting oxypnictide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Reisner, Andreas; Kidszun, Martin; Reich, Elke; Holzapfel, Bernhard; Schultz, Ludwig; Haindl, Silvia [IFW Dresden, Institute of Metallic Materials (Germany); Thersleff, Thomas [Uppsala University, Angstrom Laboratory (Sweden)

    2012-07-01

    We present an overview on the oxypnictide thin film preparation. So far, only LaAlO{sub 3} (001) single crystalline substrates provided a successful growth using pulsed laser deposition in combination with a post annealing process. Further experiments on the in-situ deposition will be reported. The structure of the films was investigated by X-ray diffractometry and transmission electron microscopy. Transport properties were measured with different applied fields to obtain a magnetic phase diagram for this new type of superconductor.

  19. Mechanics of Thin Films

    Science.gov (United States)

    1992-02-06

    and the second geometry was that of squat cylinders (diameter 6.4 mm, height 6.4 mm). These two geometries were tested in thermal shock tests, and a...milder [13]. More recently, Lau, Rahman and stressa nce ntrati, tha n films of lmalla rat ve spc Delale calculated the free edge singularity for stress...thickness of 3 mm); the second geometry was that As an example of the shielding effect of thin films, we of squat cylinders (diameter 6.4 mm, height 6.4

  20. Den umulige film

    DEFF Research Database (Denmark)

    Moestrup, Steffen Damkjær

    2014-01-01

    Den smertelige Sorg og Glæde fuldender en lang og glorværdig karriere for danske Nils Malmros. Den er en yderst vellykket film, fordi den forbliver usentimental om en skæbnesvanger dag i instruktørens liv.......Den smertelige Sorg og Glæde fuldender en lang og glorværdig karriere for danske Nils Malmros. Den er en yderst vellykket film, fordi den forbliver usentimental om en skæbnesvanger dag i instruktørens liv....

  1. Thin film ceramic thermocouples

    Science.gov (United States)

    Gregory, Otto (Inventor); Fralick, Gustave (Inventor); Wrbanek, John (Inventor); You, Tao (Inventor)

    2011-01-01

    A thin film ceramic thermocouple (10) having two ceramic thermocouple (12, 14) that are in contact with each other in at least on point to form a junction, and wherein each element was prepared in a different oxygen/nitrogen/argon plasma. Since each element is prepared under different plasma conditions, they have different electrical conductivity and different charge carrier concentration. The thin film thermocouple (10) can be transparent. A versatile ceramic sensor system having an RTD heat flux sensor can be combined with a thermocouple and a strain sensor to yield a multifunctional ceramic sensor array. The transparent ceramic temperature sensor that could ultimately be used for calibration of optical sensors.

  2. NMR characterization of thin films

    Science.gov (United States)

    Gerald II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

    2010-06-15

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  3. Film beyond boundaries: film, migrant narratives and other media Film beyond boundaries: film, migrant narratives and other media

    OpenAIRE

    Anelise Reich Corseuil

    2008-01-01

    The articles here presented are representative of the debates about the various transformational aspects of film studies, fostering the discussion about the transformations and interactions between national and international narrative forms, the interrelations between film and literature, and film with other media. The critical perspectives here presented range from an emphasis on cultural materialism, dialogism, reception theory, deconstructionism, narrative studies to film aesthetics or fil...

  4. Antikken på film

    DEFF Research Database (Denmark)

    Krasilnikoff, Jens

    2012-01-01

    Review af forskning om den græsk-romerske oldtid på film. Dertil en skitse til videre arbejde med antikken på film ud fra et historiefagligt og kulturhistorisk udgangspunkt.......Review af forskning om den græsk-romerske oldtid på film. Dertil en skitse til videre arbejde med antikken på film ud fra et historiefagligt og kulturhistorisk udgangspunkt....

  5. NMR characterization of thin films

    Science.gov (United States)

    Gerald, II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

    2008-11-25

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  6. Rare Earth Oxide Thin Films

    CERN Document Server

    Fanciulli, Marco

    2007-01-01

    Thin rare earth (RE) oxide films are emerging materials for microelectronic, nanoelectronic, and spintronic applications. The state-of-the-art of thin film deposition techniques as well as the structural, physical, chemical, and electrical properties of thin RE oxide films and of their interface with semiconducting substrates are discussed. The aim is to identify proper methodologies for the development of RE oxides thin films and to evaluate their effectiveness as innovative materials in different applications.

  7. Film in Education: This Worked For Me.

    Science.gov (United States)

    Breen, Myles P.

    Several techniques for teaching film appreciation to adults are discussed, including the use of audio cassettes, instructional films, silent films, and film dissection. Included are the techniques, philosophy, and content of a seminar on the short film, in which the short film is viewed as a variant of a short story, a pop song, a joke, and a…

  8. Estimating Effective Dose from Phantom Dose Measurements in Atrial Fibrillation Ablation Procedures and Comparison of MOSFET and TLD Detectors in a Small Animal Dosimetry Setting

    Science.gov (United States)

    Anderson-Evans, Colin David

    Two different studies will be presented in this work. The first involves the calculation of effective dose from a phantom study which simulates an atrial fibrillation (AF) ablation procedure. The second involves the validation of metal-oxide semiconducting field effect transistors (MOSFET) for small animal dosimetry applications as well as improved characterization of the animal irradiators on Duke University's campus. Atrial Fibrillation is an ever increasing health risk in the United States. The most common type of cardiac arrhythmia, AF is associated with increased mortality and ischemic cerebrovascular events. Managing AF can include, among other treatments, an interventional procedure called catheter ablation. The procedure involves the use of biplane fluoroscopy during which a patient can be exposed to radiation for as much as two hours or more. The deleterious effects of radiation become a concern when dealing with long fluoroscopy times, and because the AF ablation procedure is elective, it makes relating the risks of radiation ever more essential. This study hopes to quantify the risk through the derivation of dose conversion coefficients (DCCs) from the dose-area product (DAP) with the intent that DCCs can be used to provide estimates of effective dose (ED) for typical AF ablation procedures. A bi-plane fluoroscopic and angiographic system was used for the simulated AF ablation procedures. For acquisition of organ dose measurements, 20 diagnostic MOSFET detectors were placed at selected organs in a male anthropomorphic phantom, and these detectors were attached to 4 bias supplies to obtain organ dose readings. The DAP was recorded from the system console and independently validated with an ionization chamber and radiochromic film. Bi-plane fluoroscopy was performed on the phantom for 10 minutes to acquire the dose rate for each organ, and the average clinical procedure time was multiplied by each organ dose rate to obtain individual organ doses. The

  9. Radical Pedagogy, Prison, and Film

    Science.gov (United States)

    O'Neill, Dierdre

    2015-01-01

    This article explores the work of The Inside Film project. Inside Film works with a specific group of people (prisoners and ex-prisoners) in a particular set of circumstances (in prison or on parole) exploring how film making can be used within prison education or with people who have been to prison as a means of fostering a critical engagement…

  10. Film Analysis through Linguistic Base

    Science.gov (United States)

    Tanriverdi, Belgin

    2007-01-01

    Studies made in the last few years show that using films in language classrooms is an effective way in teaching a foreign language. Well-chosen films can serve as a valuable pedagogical aid, both for classroom use and self-study. This article is about using films in language classrooms through a specially designed course, whose outline description…

  11. Diamond films: Historical perspective

    Energy Technology Data Exchange (ETDEWEB)

    Messier, R. [Pennsylvania State Univ., University Park (United States)

    1993-01-01

    This section is a compilation of notes and published international articles about the development of methods of depositing diamond films. Vapor deposition articles are included from American, Russian, and Japanese publications. The international competition to develop new deposition methodologies is stressed. The current status of chemical vapor deposition of diamond is assessed.

  12. The magnetohydrodynamic squeeze film

    International Nuclear Information System (INIS)

    Hamza, E.A.

    1987-06-01

    The motion of an electrically conducting fluid film squeezed between two parallel disks in the presence of a magnetic field applied perpendicular to the disks is studied. Analytic solutions through use of a regular perturbation scheme are obtained. The results show that the electromagnetic forces increase the load carrying capacity considerably. (author). 5 refs, 10 figs, 3 tabs

  13. A Film Canister Colorimeter.

    Science.gov (United States)

    Gordon, James; James, Alan; Harman, Stephanie; Weiss, Kristen

    2002-01-01

    A low-cost, low-tech colorimeter was constructed from a film canister. The student-constructed colorimeter was used to show the Beer-Lambert relationship between absorbance and concentration and to calculate the value of the molar absorptivity for permanganate at the wavelength emission maximum for an LED. Makes comparisons between this instrument…

  14. FILM I KUFFERTEN

    DEFF Research Database (Denmark)

    Johansen, Stine Liv; Hansen, Adriana Maria

    2013-01-01

    kulturen, medierne er i kulturen – også i legekulturen. Denne rapport beskriver og undersøger et særligt eksempel på medialiseret leg. På baggrund af feltstudier i fem danske børnehaver, hvor et nyt filmpædagogisk materiale – Film i Kufferten - introduceres, er det rapportens formål at eksemplificere...

  15. Filmens krop, kroppens film

    DEFF Research Database (Denmark)

    Moestrup, Steffen Damkjær

    2014-01-01

    Vi har i nyere tid set en lind strøm af dokumentarfilm, der iscenesætter afvigende kroppe. Det gælder film som Shape of the Shapeless (2010), Herbstgold (2010), Beating Time (2010), Planet of Snail (2011), Whole (2003) og Kinbaku – the Art of Bondage (2009). Fælles for filmene er, at de dels...

  16. History, Memory and Film

    DEFF Research Database (Denmark)

    Bondebjerg, Ib

    In this paper I discuss history and memory from a theoretical and philosophical point of view and the non-fiction and fiction aspects of historical representation. I use Edgar Reitz’ monumental work Heimat 1-3 (and his recent film Die Andere Heimat) as examples of very different transformative...

  17. Our Favorite Film Shocks

    DEFF Research Database (Denmark)

    Willerslev, Rane; Suhr, Christian

    2014-01-01

    The modern medium of film has long been hailed for its capacity for producing shocks of an entertaining, thought-provoking, or even politically emancipative nature. But what is a shock, how and when does it occur, how long does it last, and are there particular techniques for producing cinematic...

  18. Intercultural Training with Films

    Science.gov (United States)

    Roell, Christine

    2010-01-01

    Films are a great medium to use not only to practice English, but also to facilitate intercultural learning. Today English is a global language spoken by people from many countries and cultural backgrounds. Since culture greatly impacts communication, it is helpful for teachers to introduce lessons and activities that reveal how different…

  19. "Gudbai, Lenin!" - film goda

    Index Scriptorium Estoniae

    2003-01-01

    Euroopa Filmiakadeemia tänavused auhinnasaajad : Saksa film "Good bye, Lenin!" võitis 6 auhinda, kaasaarvatud parima filmi tiitel. Parim režissöör - Lars von Trier "Dogville'i" eest, aasta üllatus - Andrei Zvjagintsevi "Tagasitulek"

  20. Introduction to Film.

    Science.gov (United States)

    Burns, Gary

    There are numerous ways to structure the introduction to film course so as to meet the needs of the different types of students who typically enroll. Assuming there is no production component in the course, the teacher is left with two major approaches to choose from--historical and aesthetic. The units in the course will typically be built around…

  1. Korupsi dalam Film Indonesia

    Directory of Open Access Journals (Sweden)

    Rhafidilla Vebrynda

    2015-01-01

    Full Text Available Abstract: Corruption has been rooted and institutionalized in our smallest environment. The campaign to fight corruption comes from various organizations through numerous varieties of means. This study looks at the Komisi Pemberantasan Korupsi (KPK campaign through a film entitled “Kita Versus Korupsi”. This study uses narrative analysis by looking at the elements of narrative, narrative structure, the analysis model of aktan and the Greimas’ semiotic square. It is found that the film narrates corruption as trouble and resistor. The various forms of corruption are narrated using the combination of techniques scene, dialogue and flashback. Abstrak: Korupsi sudah mengakar dan melembaga hingga lingkungan terkecil kita. Kampanye untuk melawannya datang dari berbagai pihak melalui beragam sarana. Penelitian ini melihat kampanye Komisi Pemberantasan Korupsi (KPK melalui film “Kita Versus Korupsi”. Menggunakan metode analisis naratif dengan melihat unsur naratif, struktur naratif, analisis model aktan dan oposisi segi empat Algirdas Greimas, penelitian ini menemukan bahwa korupsi dinarasikan sebagai gangguan dan penghambat. Film tersebut selalu menghadapkan pelaku korupsi dengan pihak yang tidak korupsi secara langsung. Latar belakang pengetahuan tokoh utama tentang korupsi berpengaruh dalam pengambilan keputusannya. Berbagai bentuk korupsi dinarasikan dengan teknik penggabungan scene, dialog dan flashback.

  2. Film o Heraklicie

    OpenAIRE

    Tytko, Marek Mariusz

    1987-01-01

    Tekst jest wierszem metafizycznym o relacji człowieka ze światem na przykładzie filozofii Heraklita i manipulacji filmowej. The text is a metaphysical verse on relationship a man and the world for example philosophy of Heraclitus and film manipulation.

  3. Film selection in medical radiology

    International Nuclear Information System (INIS)

    Bor, Dogan

    1988-01-01

    Importing of medical imaging films is the responsibility of Turkish Red Croscend, but some institutions have currently started to import their own films. Because of the different resources in individual departments throughout Turkey, a general purpose medical film is imported by Turkish Red Croscend. This kind of film has the advantage to tolerate some technical faults related to the exposure, dark room and processing conditions and still reveals the necessary image quality. In addition to general purpose film, many companies produce special used films which improve some film characteristics in order to have a better image. The initial results of a project already started by Turkish Atomic Energy Authority showed that some other technical reasons prevent obtaining films with optimum quality. The film is the last step of diagnostic procedure and not only gives necessary clinical information, but also visualizes all the problems related to the lock of the calibration of X-ray system and dark room processing conditions. Because of these reasons, many people hold the film responsible for every technical problem. During the selection of the best film among the different companies, institutions have to fulfill some prerequisites at the beginning and than evaluate the quantitative results obtained from measurements according to their clinical purposes. It is the subject of this paper to show how to use film parameter as a comparison to different types of films measured with light sensitometry method. The dark room and processing problems which adversely effect the results are also given. The requirements for the best film selection both for general and special purposes are also evaluated. The extent of this paper is limited only to films using radiology and does not cover the types used in other imaging areas

  4. Ion beam assisted film growth

    CERN Document Server

    Itoh, T

    2012-01-01

    This volume provides up to date information on the experimental, theoretical and technological aspects of film growth assisted by ion beams.Ion beam assisted film growth is one of the most effective techniques in aiding the growth of high-quality thin solid films in a controlled way. Moreover, ion beams play a dominant role in the reduction of the growth temperature of thin films of high melting point materials. In this way, ion beams make a considerable and complex contribution to film growth. The volume will be essential reading for scientists, engineers and students working in thi

  5. Handbook of thin film technology

    CERN Document Server

    Frey, Hartmut

    2015-01-01

    “Handbook of Thin Film Technology” covers all aspects of coatings preparation, characterization and applications. Different deposition techniques based on vacuum and plasma processes are presented. Methods of surface and thin film analysis including coating thickness, structural, optical, electrical, mechanical and magnetic properties of films are detailed described. The several applications of thin coatings and a special chapter focusing on nanoparticle-based films can be found in this handbook. A complete reference for students and professionals interested in the science and technology of thin films.

  6. Development of nano-sized α-Al2O3:C films for application in digital radiology

    International Nuclear Information System (INIS)

    Silva, Edna C.

    2011-01-01

    Ceramic materials are widely used as sensors for ionizing radiation. In nuclear applications, the alpha-alumina doped with carbon (α-Al 2 O 3 :C) is the most widely ceramic used because of its excellent optically stimulated luminescence (OSL) and thermoluminescent (TL) properties applied to detection of ionizing radiation. Another application of OSL and TL materials are in Digital Radiography, with ceramic/polymeric film composites. Recently, Computed Radiography (CR) devices based on OSL materials are replacing the old conventional film radiography. In this study we investigate the thermoluminescence of nano-sized α-Al 2 O 3 samples doped with different percentages of carbon, sintered in reducing atmospheres at temperatures ranging from 1300 to 1750 deg C. The results indicate that the nano-sized α-Al 2 O 3 :C materials have a luminescent response that could be due to both OSL and RPL properties, but without application to radiation dosimetry. Moreover, the results indicate that micro-sized α-Al 2 O 3 :C, doped with 0.5% carbon, and nano-sized ones doped with 2% of carbon, present thermoluminescent signal around 30 to 100 times the TL output signal of commercial TLD-100, the most used TL dosimeter in the world. The results indicate that these ceramic nano-particles have great potential for use in Digital Radiography based on thermoluminescent film imaging, being able to provide image resolutions much higher than the micro-sized α-Al 2 O 3 :C, in view of their improved resolution provided by nano-particulates. (author)

  7. Professor Camillo Negro's Neuropathological Films.

    Science.gov (United States)

    Chiò, Adriano; Gianetto, Claudia; Dagna, Stella

    2016-01-01

    Camillo Negro, Professor in Neurology at the University of Torino, was a pioneer of scientific film. From 1906 to 1908, with the help of his assistant Giuseppe Roasenda and in collaboration with Roberto Omegna, one of the most experienced cinematographers in Italy, he filmed some of his patients for scientific and educational purposes. During the war years, he continued his scientific film project at the Military Hospital in Torino, filming shell-shocked soldiers. In autumn 2011, the Museo Nazionale del Cinema, in partnership with the Faculty of Neurosciences of the University of Torino, presented a new critical edition of the neuropathological films directed by Negro. The Museum's collection also includes 16 mm footage probably filmed in 1930 by Doctor Fedele Negro, Camillo's son. One of these films is devoted to celebrating the effects of the so-called "Bulgarian cure" on Parkinson's disease.

  8. Host thin films incorporating nanoparticles

    Science.gov (United States)

    Qureshi, Uzma

    The focus of this research project was the investigation of the functional properties of thin films that incorporate a secondary nanoparticulate phase. In particular to assess if the secondary nanoparticulate material enhanced a functional property of the coating on glass. In order to achieve this, new thin film deposition methods were developed, namely use of nanopowder precursors, an aerosol assisted transport technique and an aerosol into atmospheric pressure chemical vapour deposition system. Aerosol assisted chemical vapour deposition (AACVD) was used to deposit 8 series of thin films on glass. Five different nanoparticles silver, gold, ceria, tungsten oxide and zinc oxide were tested and shown to successfully deposit thin films incorporating nanoparticles within a host matrix. Silver nanoparticles were synthesised and doped within a titania film by AACVD. This improved solar control properties. A unique aerosol assisted chemical vapour deposition (AACVD) into atmospheric pressure chemical vapour deposition (APCVD) system was used to deposit films of Au nanoparticles and thin films of gold nanoparticles incorporated within a host titania matrix. Incorporation of high refractive index contrast metal oxide particles within a host film altered the film colour. The key goal was to test the potential of nanopowder forms and transfer the suspended nanopowder via an aerosol to a substrate in order to deposit a thin film. Discrete tungsten oxide nanoparticles or ceria nanoparticles within a titanium dioxide thin film enhanced the self-cleaning and photo-induced super-hydrophilicity. The nanopowder precursor study was extended by deposition of zinc oxide thin films incorporating Au nanoparticles and also ZnO films deposited from a ZnO nanopowder precursor. Incorporation of Au nanoparticles within a VO: host matrix improved the thermochromic response, optical and colour properties. Composite VC/TiC and Au nanoparticle/V02/Ti02 thin films displayed three useful

  9. Silk Film Embossing System

    Science.gov (United States)

    Paquette, Mark S.

    New tools are often required to facilitate new discoveries and test new methods. Commercial offerings can be prohibitively expensive and difficult to customize. The development of ad-hoc tools provides the most flexibility and provides an opportunity to modify and refine a technology. An embossing system was developed for silk film imprinting and stamping in order to facilitate and add versatility to the efforts involving micro- and nanoscale device manufacturing in biopolymers. This system features temperature controlled embossing surfaces, adjustable embossing pressures, and variable embossing times. The device can also be fitted with interchangeable temperature controlled embossing and stamping tools. The design, development, fabrication, applications, and future improvements are explored for the system. This device may facilitate new discoveries in the realm of biopolymer micro- and nanomanufacturing and may provide a path towards high volume production of silk film based technologies.

  10. Reading through Films

    Directory of Open Access Journals (Sweden)

    Madhavi Gayathri Raman

    2016-02-01

    Full Text Available This paper captures the design of a comprehensive curriculum incorporating the four skills based exclusively on the use of parallel audio-visual and written texts. We discuss the use of authentic materials to teach English to Indian undergraduates aged 18 to 20 years. Specifically, we talk about the use of parallel reading (screen-play and audio-visual texts (Shawshank Redemption, and Life is Beautiful, A Few Good Men and Lion King drawn from popular culture in the classroom as an effective teaching medium. Students were gradually introduced to films based on novels with extracts from the original texts (Schindler’s List, Beautiful Mind for extended reading and writing practice. We found that students began to pay more attention to aspects such as pronunciation, intonational variations, discourse markers and vocabulary items (phrasal verbs, synonyms, homophones, and puns. Keywords: Reading, films, popular culture, ESL classroom, language skills

  11. Strategic Talk in Film.

    Science.gov (United States)

    Payr, Sabine; Skowron, Marcin; Dobrosovestnova, Anna; Trapp, Martin; Trappl, Robert

    2017-01-01

    Conversational robots and agents are being designed for educational and/or persuasive tasks, e.g., health or fitness coaching. To pursue such tasks over a long time, they will need a complex model of the strategic goal, a variety of strategies to implement it in interaction, and the capability of strategic talk. Strategic talk is incipient ongoing conversation in which at least one participant has the objective of changing the other participant's attitudes or goals. The paper is based on the observation that strategic talk can stretch over considerable periods of time and a number of conversational segments. Film dialogues are taken as a source to develop a model of the strategic talk of mentor characters. A corpus of film mentor utterances is annotated on the basis of the model, and the data are interpreted to arrive at insights into mentor behavior, especially into the realization and sequencing of strategies.

  12. Polyether ether ketone film. Polyether ether ketone film

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, S. (Sumitomo Chemical Co. Ltd., Tokyo (Japan))

    1990-07-05

    The characteristics and the film making process of polyether ether ketone (PEEK) resin, and the characteristics and the applications of PEEK film, are described. PEEK is aromatic polyketone with super thermal resistance. Though it is a crystalline polymer of which the crystallinity is controlled to 48% in a highest degree, it has also amorphous property, thus it shows unique property. The characteristics of PEEK resin are found in thermal resistance, incombusti-bility, transparency, chemical resistance, light resistance and radiation resistance. As for the film making process, casting method by T-die is generally adopted. The general properties of PEEK film are excellent in high thermal resistance, good electrical properties, chemical resistance, hydrolysis resistance, radiation resistance and imcombusti-bility. In the application of PEEK film, new development is expected in following fields; a high performance composite, flexible print substrate with high thermal resistance, insulating tape with thermal resistance, and a general film in the nuclear energy industry. 5 figs., 5 tabs.

  13. Thin film processes

    CERN Document Server

    Vossen, John L

    1978-01-01

    Remarkable advances have been made in recent years in the science and technology of thin film processes for deposition and etching. It is the purpose of this book to bring together tutorial reviews of selected filmdeposition and etching processes from a process viewpoint. Emphasis is placed on the practical use of the processes to provide working guidelines for their implementation, a guide to the literature, and an overview of each process.

  14. Darwinisme, film og filmteori

    DEFF Research Database (Denmark)

    Grodal, Torben Kragh

    2010-01-01

    Artiklen giver først en oversigt over evolutionshistorisk baseret kulturanalyse og dennes tilknytning til neuropsykologi, herunder evolutionsteoretiske studier af religion og andre overnaturlige forestillingssystemer. Derefter redegøres der kort for, hvorledes Darwinismen har  stødt på modstand, ...... kulturhistoriske baggrund for retssag og film.   Keywords: evolutionsteori, filmteori, evolutionær religionsanalyse, Inherit the wind.     Udgivelsesdato: april 2010...

  15. Ellipsometry of anodic film growth

    Energy Technology Data Exchange (ETDEWEB)

    Smith, C.G.

    1978-08-01

    An automated computer interpretation of ellisometer measurements of anodic film growth was developed. Continuous mass and charge balances were used to utilize more fully the time dependence of the ellipsometer data and the current and potential measurements. A multiple-film model was used to characterize the growth of films which proceeds via a dissolution--precipitation mechanism; the model also applies to film growth by adsorption and nucleation mechanisms. The characteristic parameters for film growth describe homogeneous and heterogeneous crystallization rates, film porosities and degree of hydration, and the supersaturation of ionic species in the electrolyte. Additional descriptions which may be chosen are patchwise film formation, nonstoichiometry of the anodic film, and statistical variations in the size and orientation of secondary crystals. Theories were developed to describe the optical effects of these processes. An automatic, self-compensating ellipsometer was used to study the growth in alkaline solution of anodic films on silver, cadmium, and zinc. Mass-transport conditions included stagnant electrolyte and forced convection in a flow channel. Multiple films were needed to characterize the optical properties of these films. Anodic films grew from an electrolyte supersatuated in the solution-phase dissolution product. The degree of supersaturation depended on transport conditions and had a major effect on the structure of the film. Anodic reaction rates were limited by the transport of charge carriers through a primary surface layer. The primary layers on silver, zinc, and cadmium all appeared to be nonstoichiometric, containing excess metal. Diffusion coefficients, transference numbers, and the free energy of adsorption of zinc oxide were derived from ellipsometer measurements. 97 figures, 13 tables, 198 references.

  16. Polymer Thin Film Stabilization.

    Science.gov (United States)

    Costa, A. C.; Oslanec, R.; Composto, R. J.; Vlcek, P.

    1998-03-01

    We study the dewetting dynamics of thin polystyrene (PS) films deposited on silicon oxide surfaces using optical (OM) and atomic force (AFM) microscopes. Quantitative analysis of the hole diameter as a function of annealing time at 175^oC shows that blending poly(styrene-block-methyl-methacrylate) (PS-b-PMMA) with PS acts to dramatically slow down the dewetting rate and even stops holes growth before they impinge. AFM studies show that the hole floor is smooth for a pure PS film but contains residual polymer for the blend. At 5% vol., a PS-b-PMMA with high molar mass and low PMMA is a more effective stabilizing agent than a low molar mass/high PMMA additive. The optimum copolymer concentration is 3% vol. beyond which film stability doesn't improve. Although dewetting is slowed down relative to pure PS, PS/PS-b-PMMA bilayers dewet at a faster rate than blends having the same overall additive concentration.

  17. Automatic film loader for X-ray spot film device

    International Nuclear Information System (INIS)

    1975-01-01

    A light tight tunnel extends over the top of a diagnostic X-ray table. A film cassette is mounted for reciprocating in the tunnel between an X-ray exposure position and a position in which the cassette is unloaded or loaded with film automatically. Unexposed films are dispensed one at a time into the cassette from a feed magazine at one end of the tunnel. After exposure, the film is ejected from the cassette into a receiving magazine at the same end of the tunnel. (Auth.)

  18. FOREIGN LANGUAGE FILMS IN LOUISIANA DEPOSITORIES.

    Science.gov (United States)

    BABINEAUX, AUDREY

    THIS MANUAL IS AN ANNOTATED LIST OF 16-MILLIMETER EDUCATIONAL FOREIGN LANGUAGE FILMS (BOTH LINGUISTIC AND CULTURAL) WHICH WERE PURCHASED WITH STATE AND FEDERAL FUNDS AND PLACED IN LOUISIANA'S NINE FILM LIBRARIES. FILMS ARE ARRANGED ALPHABETICALLY BY LANGUAGES. FILMS IN THE TARGET LANGUAGE ARE LISTED SEPARATELY FROM FILMS WITH ENGLISH NARRATION. A…

  19. Olympic Training Film Profiles. Volume III.

    Science.gov (United States)

    1971

    Approximately 250 instructional films are described in Volume Three (1970-1971) of this review. After an introduction which considers film discussions from the instructor's point of view and offers some ideas for conducting a film showing and ordering the films, profiles of the films are presented grouped under such areas as management…

  20. Silent Film in the German Classroom.

    Science.gov (United States)

    Caldwell, David

    In addition to using films in the German classroom to introduce students to German culture and history, it is important to show and study the film as film. This procedure emphasizes the importance of the film as a part of creative arts in Germany and demands student participation in observation and discussion. Many German silent films are…