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Sample records for tl dosimeters developed

  1. Development of a TL personal dosimeter identifiable PA exposure, and comparison with commercial TL dosimeters

    International Nuclear Information System (INIS)

    Kwon, J.W.; Kim, H.K.; Lee, J.K.; Kim, J.L.

    2004-01-01

    A single-dosimeter worn on the anterior surface of the body of a worker was found to significantly underestimate the effective dose to the worker when the radiation comes from the back. Several researchers suggested that this sort of underestimation can be corrected to a certain extent by using an extra dosimeter on the back. However, use of multiple dosimeters also has disadvantages such as complication in control or incurrence of extra cost. Instead of the common multi-dosimeter approach, in this study, a single dosimeter introducing asymmetric filters which enabled to identify PA exposure was designed, and its dose evaluation algorithm for AP-PA mixed radiation fields was established. A prototype TL personal dosimeter was designed and constructed. The Monte Carlo simulations were utilized in the design process and verified by experiments. The dosimeter and algorithm were applicable to photon radiation having an effective energy beyond 100 keV in AP-PA mixed radiation fields. A simplified performance test based on ANSI N13.11 showed satisfactory results. Considering that the requirements of the International Electrotechnical Commission (IEC) and the American National Standards Institute (ANSI) with regard to the dosimeter on angular dependency is reinforced, the dosimeter and the dose evaluation algorithm developed in this study provides a useful approach in practical personal dosimetry against inhomogeneous high energy radiation fields. (author)

  2. Preliminary results on TL and OSL aluminium oxide dosimeters developed at IPEN

    Energy Technology Data Exchange (ETDEWEB)

    Fukumori, David T.; Yoshito, Walter K.; Ussui, Valter; Lazar, Dolores R.R.; Campos, Leticia L., E-mail: fukumori@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    The aluminum oxide composes the modern TL and OSL radiation dosimeters. TL and OSL phenomena are related to chemical elements in the crystalline structure of {alpha}-Al{sub 2}O{sub 3}. The aim of this work was to develop materials based on aluminum oxide for use in TL and OSL dosimetry. The studies included the dosimetric properties of alumina samples obtained by electro fusion, adsorption and coprecipitation. Electro fused alumina commercially available as abrasive particles was used to produce the pellets by glass sintering. Adsorption and coprecipitation were the methods used to insert metal ions to alumina. The best results were achieved with electro fused alumina and Tm{sup 3+} doped Al{sub 2}O{sub 3} pellets. The electro fused alumina-glass pellets show TL and OSL signals and the TL curve has two peaks. Its minimum detectable radiation dose is 7.2 mGy and the linearity of TL response as function of dose is up to about 800 mGy. The {alpha}-Al{sub 2}O{sub 3}:Tm pellets produced by sintering at 1550 deg C presented a meaningful TL glow curve so that it is worth studying their properties and viability of use in dosimetry. (author)

  3. Environmental monitoring by CaSO4:Dy TL dosimeters

    International Nuclear Information System (INIS)

    Deme, S.; Szabo, P.P.

    1975-12-01

    The thermoluminescent dosimeters of high sensitivity are useful for monitoring the area near nuclear installations. CaSO 4 :Dy TL dosimeters have high sensitivity and low fading so that by means of them the dose from the background can be measured with an accuracy of 10-20%. An increase of 2 mR in the background can be observed and doses as high as 1000R can be registered with an accuracy of 5%. The measuring method and results are reported here. For two years these CaSO 4 :Dy dosimeters have been successfully used at the site of the Central Research Institute for Physics. (K.A.)

  4. Measurement of effective dose in clinic radiation diagnosis with TL dosimeters developed in Mexico; Medicion de dosis efectiva en radiodiagnostico clinico con dosimetros TL desarrollados en Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Martinez, Pedro R. [Instituto Nacional de Investigaciones Nucleares, Mexico, D.F. (Mexico); Azorin Nieto, Juan [Universidad Autonoma Metropolitana-Iztapalapa, Mexico D.F. (Mexico); Gonzalez Urquidi, Blanca [Universidad Veracruzana, Xalapa (Mexico); Maldonado Sanchez, Guadalupe [Instituto Mexicano del Seguro Social (IMSS), Toluca (Mexico). Hospital de Gineco Obstetricia

    2001-07-01

    At the moment the radiation diagnosis is one of the main causes of exposition to the ionizing radiations, and in many of the cases the limits to the limits of dose established by the Commission the International of Radiological safety are not applied. In this work the results obtained in the measurement of the effective dose with dosemeters Tl of LiF:Mg,Cu, P+PTFE developed in the National Institute of Nuclear Investigations (ININ), in patients to studies of clinical radiation diagnosis of urography and hysterosalpingography. The effective dose was considered in gonads, breasts and thyroid. Whereas in the radiologist physician the dose was measured in crystalline, thyroid and hands, in this work ware made whole body measurements in addition. The results showed that the dose received by patients is equivalent with the results reported in Literature; in the case of the radiologist physician, the dose considered in the made studies is below the limits recommended for POE.

  5. Development of Thermoluminescence Dosimeter CaSO4:Dy as Personal and Environmental Dosimeters

    International Nuclear Information System (INIS)

    Hasnel Sofyan

    2009-01-01

    Development of personal and environmental dosimeters using material phosphors of CaSO 4 :Dy powder in form capillary glass and disc teflon thermoluminescence (TL) dosimeter have been done. TL dosimeter CaSO 4 :Dy powder used can record dose response less than 0.01 mGy. Fading of TL dosimeter capillary glass after 29 days is 25%. In 1 batch, making of CaSO 4 :Dy powder can obtain 2 groups of dosimeter capillaries with coefficient variance smaller than 10%. This discrepancy caused difference in powder making and reading of the TL dosimeter. TL dosimeter CaSO 4 :Dy teflon disc with dia. 5 mm and 0.8 mm thickness is homogeneous mixture between phosphor powder with dia. 80 to 150 mesh and teflon powder dia. 20 μm. The composition of CaSO 4 :Dy and teflon in TL dosimeter influence sensitivity of the dosimeter. It’ concluded that in order to obtain optimal sensitivity of TL dosimeter, the composition of CaSO 4 :Dy and teflon is 3 and 1 with pressured of disc in 700 MPa. (author).

  6. Comparison of laboratory and in situ evaluation of environmental TL dosimeters

    International Nuclear Information System (INIS)

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

    1996-01-01

    The passive environmental gamma-radiation dosimetry is mainly based on TL (thermoluminescent) dosimetry. This method offers considerable advantages due to its high precision, low cost, wide range, etc.. At the same time its application 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 dosimeter at the place of exposure (in situ TLD reader) eliminates the disadvantages mentioned above. A microprocessor based portable TLD reader was developed by us for monitoring environmental gamma-radiation doses. Using a portable reader for in situ evaluation there are several disadvantages as well. The method requires the transport of the reader instead of dosimeters. The portable reader should be battery operated with low power consumption. Due to this requirement the temperature stabilization of the reader requests different solution as in laboratory type devices. Comparison of recently developed in situ and traditional laboratory evaluation methods of environmental TL dosimeters is given in recent paper. The comparison was made in the same conditions. The most characteristic - for environmental monitoring - numerical TL data (dose range, reproducibility, fading, self dose etc.) are given for manufactured by us CaSO 4 :Dy bulbs (portable reader) and very advantageous, high sensitive Al 2 O 3 :C dosimeters (laboratory evaluation). (author)

  7. Magnetic field dosimeter development

    International Nuclear Information System (INIS)

    Lemon, D.K.; Skorpik, J.R.; Eick, J.L.

    1980-09-01

    In recent years there has been increased concern over potential health hazards related to exposure of personnel to magnetic fields. If exposure standards are to be established, then a means for measuring magnetic field dose must be available. To meet this need, the Department of Energy has funded development of prototype dosimeters at the Battelle Pacific Northwest Laboratory. This manual reviews the principle of operation of the dosimeter and also contains step-by-step instructions for its operation

  8. Photon and neutron energy response of Thermoluminescent (TL) dosimeters

    International Nuclear Information System (INIS)

    Thilagam, L.; Priya, M.R.; Mohapatra, D.K.

    2018-01-01

    Theoretical Monte Carlo (MC) simulations are carried out to investigate the relative thermoluminesence (TL) response of the most commonly used TLD materials to a wide range of photon energy. The effect of polytetrafluoroethylene (PTFE) on TL response of CaSO 4 :Dy is also studied. Additionally, the neutron response of LiF:Mg,Ti TL materials with different concentrations of 6 Li is estimated in terms of the number of 6 Li(n, t) 4 He capture reactions for a wider neutron energy

  9. Sand as in situ TL dosimeter in radiation hygienisation of sewage sludge

    International Nuclear Information System (INIS)

    Benny, P.G.; Bhatt, B.C.

    1999-01-01

    Recently, we have investigated the thermoluminescence (TL) properties of the sand, collected from the sewage sludge, after various extensive cleansing procedures. In the present studies, the sand separated from the sludge was used to estimate irradiation dose to sludge at Sludge Hygienisation Research Irradiator (SHRI), Vadodara, India. A dose vs TL response calibration curve was established for the 220 deg. C TL peak for the hydrogen peroxide (H 2 O 2 )-treated and HF-treated sludge sand samples collected from the unirradiated batch. This was used to estimate the dose absorbed in the corresponding batch of the irradiated sludge. Similar curve was plotted for the 370 deg. C TL peak for the HF-treated sand samples for its application as an in-situ dosimeter. Using this method, the absorbed dose rate delivered to the sludge during irradiation at SHRI was estimated to be 0.49 ± 0.02 kGy per hour. Also, the saturation levels of the TL response curves for these peaks are reported here. (author)

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

    Science.gov (United States)

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

    2005-04-01

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

  11. Characteristics Of Dosimeter TL CaSO4:Dy Glass Capillaries For Environmental Radiation Dose Monitoring

    International Nuclear Information System (INIS)

    Sofyan Hasnel; Yulianti, Helfi; Ramain, Abubakar; Kusumawati, Dyah D.; Suyati

    2000-01-01

    research on the characteristic of dosimeter TL CaSO 4 : Dy glass capillaries for environmental dose radiation have been carried out. The results obtained are uniform response and reproducibility during three cycles consumption with average percentage standard deviation of 7.31 % and 5.45%. The response dose is linear and has a minimum detectable dose of 0.01 mGy, sunshine effect with non-penetrating light capsule of 4.65%, humidity effects is not significant by using non-penetrating light capsule. Radiation dose information during 30 days are fading 25%

  12. Evaluation of spurious readings in Los Alamos personnel TL dosimeters

    International Nuclear Information System (INIS)

    Eisen, Y.; Littlejohn, G.J.; Cortez, J.R.

    1984-08-01

    This study investigates the possibility of tritium build-up in TLD-600 chips irradiated with neutrons and the causes of spurious readings in the Harshaw TLD cards used for personnel dosimetry. Experiments indicated that spurious readings in TLD-600 chips, previously irradiated with neutrons, might occur in cases where the cards had been accidentally read at temperatures lower than 300 0 C as a result of bad contact between the hot finger in the reading system and the chips. Because a TLD card contains glue and paper bar-code labels, the postannealing is performed at 80 0 C for 17 hours. This annealing procedure alone does not effectively deplete the high-energy traps, such as those near 260 0 C, populated by high-LET (Linear Energy Transfer) particles. TLD-600 chips, irradiated on a phantom by 400 mrem of moderated fission neutrons, read at 240 0 C, annealed at 80 0 C for 17 hours, and then reread at 280 0 C, showed residual doses as large as 200 mrem (equivalent photons). Calculations and experiments show that for neutron exposures around 1 rem of moderated fission neutrons with an average energy of 500 keV, the maximum build-up of dose as a result of tritium formation is less than 1 mrem. The dose build-up in properly annealed TLD-600 and TLD-700 chips, is nearly the same, even though the TLD-600 chips were previously irradiated by neutrons. Both kinds of chips show natural background accumulation. A mechanism for annealing the Harshaw cards at high temperatures, without destroying the label or the adhesive material, was developed and found to be useful. 7 references, 4 figures, 3 tables

  13. Development of colored alumilite dosimeter

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-03-01

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

  14. Investigation of TL, OSL and PTTL properties of Mg2SiO4:Tb dosimeters

    International Nuclear Information System (INIS)

    Oguz, K. F.; Goekce, M.; Karali, T.; Harmansah, C.

    2010-01-01

    In this study thermoluminescence (TL) and optically stimulated luminescence (OSL) properties of Mg 2 SiO 4 :Tb in the form of sintered pellets were investigated. Mg 2 SiO 4 :Tb is a recently developed dosimetric material which offers high sensitivity for TL and OSL in dosimetric applications. Thermoluminescence glow curve of Tb doped Mg 2 SiO 4 samples show a glow peak at about 200 degree Celsius with two small peaks at about 275 and 330 degree Celsius, respectively. OSL experiments showed that blue light (470 nm) is six times more efficient than green light (532 nm) to stimulate the OSL emission. The aim of this study was to determine the TL and OSL fading properties of Mg 2 SiO 4 : Tb using OSL and TL methods. In addition, PTTL properties of the Mg 2 SiO 4 : Tb was investigated by using blue LEDs, UV lamp and blue laser. Investigations on the fading properties also showed that the TL signal fades % 10 in a period of 1 month and OSL signal fades % 10 in a period of 3 month, which then the signal remains relatively stable for longer periods.

  15. Characterization of TL dosimeters for determination of the gamma component in a mixed n+γ radiation field

    International Nuclear Information System (INIS)

    Ranogajec-Komor, M.; Miljanic, S.; Ferek, S.; Dvornik, I.; Osvay, M.

    1996-01-01

    In the International Intercomparison of the Criticality Accident Dosimetry Systems organized by the Commission of European Communities at SILENE Reactor in Valduc, France, 1993, the Ruder Boskovic Institute (RBI) measured the total neutron and gamma tissue absorbed dose (D n+γ ) at the body surface irrespective of neutron and gamma energy spectra variations using the chemical dosimeters DL-M4. For deriving the neutron dose i.e recoil dose, D n , from the differences D n = D n+γ - D t , the total gamma dose (D tγ ) has to be measured with highest accuracy. The determination of the gamma dose in a mixed field is complicated because TL dosimeters are sensitive both to neutrons and gammas. Besides, the radiation doses and energy spectra vary because of scattering and absorption in the body or phantom. Therefore dosimeters with different sensitivities, energy dependences and encapsulations have to be used. In this paper only the study of some characteristics of various TL detectors, such as sensitivity, linearity, supralinearity and fading, for measurement of the gamma component are described. These investigations were carried out in RBI before and after the Valduc intercomparison experiments. The encapsulations, TL response corrections for thermal and fast neutron effects as well as the discussion of Valduc results will be published later

  16. Development of colored alumilite dosimeter

    CERN Document Server

    Obara, K; Yagi, T; Yokoo, N

    2003-01-01

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

  17. Investigation of TL properties of sand collected from sewage sludge as an ''in situ'' dosimeter in radiation disinfection

    International Nuclear Information System (INIS)

    Benny, P.G.; Bhatt, B.C.

    1996-01-01

    Thermoluminescence (TL) properties of sand, collected from sewage sludge, were studied after extensive cleaning procedures. In the sand samples treated with either hydrogen peroxide (H 2 O 2 ) or hydrofluoric acid (HF), there was a prominent TL peak at about 220 o C after γ-irradiation and 120 o C, 20 min post-irradiation annealing treatment. The dose vs TL response curves in hydrogen-peroxide-treated and HF-treated sand samples were found to be linear up to 30 and 100 Gy, respectively, beyond which they were supra-linear. The extent of post-irradiation fading in the sand sample, which was treated with H 2 O 2 and post-irradiation annealed at 120 o C for 20 min, was observed to be 8% after 21 days, while no detectable fading was observed for the sample which was HF treated and annealed at 120 o C for 20 min after γ-irradiation. Therefore, H 2 O 2 - as well as HF-treated sludge sand samples could be considered for use as in situ TL dosimeters for radiation disinfection of sewage sludge. (Author)

  18. Development of a new type thyroid glands dosimeter

    International Nuclear Information System (INIS)

    He Lihua; Song Yiyang; Chen Qin; Chen Yannan

    2000-01-01

    A new dosimeter of 125 I in thyroid gland is described. The dosimeter consists of NaI(Tl) detector and intelligent data recorder. Single-chip-microcomputer is used for data handling. The activity of 125 I in thyroid glands of human being is measured directly, rapidly, and accurately. Furthermore, it can calculate and display the intake, committed dose equivalent and committed effective dose equivalent. The measuring range of 125 I in thyroid glands is 10-2 x 10 6 Bq. The dosimeter has been operating continuously for a long time with high stability

  19. Study of combinations of TL/OSL single dosimeters for mixed high/low ionization density radiation fields

    International Nuclear Information System (INIS)

    Oster, L.; Druzhyna, S.; Orion, I.; Horowitz, Y.S.

    2013-01-01

    In this paper we discuss and compare the potential application of combined OSL/TL measurements using 6 LiF:Mg,Ti (TLD-600 is enriched of isotope 6 Li which has a high cross-section for the reaction with slow neutrons) or 7 LiF:Mg,Ti ( TLD-700 is enriched of 7 Li isotope) and TLD-100 (natural isotopic composition) detectors. The OSL/TL duel readout of LiF:Mg,Ti as an ionization density discriminator avoids some of the difficulties inherent to the various types of discrimination mixed-field passive dosimeters, and in addition has several advantages. The preferential excitation of OSL compared to TL following high ionization density (HID) alpha irradiation, naturally explained via the identification of OSL with the “two-hit” F 2 or F 3 center, whereas the major component of composite TL glow peak 5 is believed to arise from a ''one-hit'' complex defect. This evidence allows near-total discrimination between HID radiation and low-ionization density (LID) radiation. Beta and alpha particle irradiations were carried out with 90 Sr/ 90 Y (∼500 keV average energy) and 241 Am sources (4.7 MeV) respectively and neutron irradiations were carried out at the PTB (Germany) (E n = 5 MeV) and RARAF (Columbia University, USA) (E n = 6 MeV) accelerator facilities. The highest values of the FOM obtained was ∼30 for neutron/gamma discrimination and ∼110 for alpha/gamma discrimination using OSL/TL – peak 5 measurements in TLD-700. -- Highlights: ► The increased response of OSL compared to TL following HID irradiation is observed. ► This evidence is explained via the identification of OSL with the ''two-hit'' F2 centers. ► The potential application of combined OSL/TL in discrimination dosimetry is discussed. ► The values of FOM were 110 for alpha/gamma and 30 for neutron/gamma discrimination

  20. Development and dosimetric evaluation of radiochromic PCDA vesicle gel dosimeters

    International Nuclear Information System (INIS)

    Sun, P.; Fu, Y.C.; Hu, J.; Hao, N.; Huang, W.; Jiang, B.

    2016-01-01

    The gel dosimeter has the unique capacity in recording radiation dose distribution in three dimensions (3D), which has the specific advantages in dosimetry measurements where steep dose gradients exist, such as in intensity-modulated radiation therapy (IMRT), brachytherapy and so on. Some 3D dosimeters, such as Fricke gel dosimeters, polymer gel dosimeters, the PRESAGE plastic dosimeters and micelle gel dosimeters have appeared recently. However, there are several disadvantages of these 3D dosimeters limit their application in radiotherapy dose verification. In this study, a novel radiochromic gel dosimeter for 3D dose verification of radiotherapy was developed by dispersing nanovesicles self-assembled by 10,12-pentacosadiynoic acid (PCDA) into the tissue equivalence gel matrix. The characteristics of radiochromic PCDA vesicle gel dosimeters were evaluated. The results indicate that these radiochromic gel dosimeters have good linear dose response to X-ray irradiation in the dose range of 2–100 Gy. In addition, the radiochromic gel dosimeters breakthrough the limitations of the existing gel dosimeters such as diffusion effect, post-radiation effect, and poor forming ability. The response of the gel dosimeter does not show any dose rate dependence, energy dependence and temperature effect, and there was no obvious difference in the gel response between single and cumulative dose of fractional irradiation. Hence, the radiochromic PCDA vesicle gel dosimeters developed in this study could be generally applied to 3D dose verification in radiotherapy. - Highlights: • A novel radiochromic gel dosimeter was developed by dispersing PCDA nanovesicles into the tissue equivalence gel matrix. • This nanovesicle overcomes the dose image blurring caused by the diffusion of monomer molecules. • This nanovesicle limits the polymer chain growth, so as to reduce the post-radiation effect. • The gel matrixes possess excellent tissue equivalence and elastic strength, which

  1. Electronic dosimeter characteristics and new developments

    International Nuclear Information System (INIS)

    Thompson, I.M.G.

    1999-01-01

    Electronic dosimeters are very much more versatile than existing passive dosimeters such as TLDs and film badges which have previously been the only type of dosimeters approved by national authorities for the legal measurement of doses to occupationally exposed workers. Requirements for the specifications and testing of electronic dosimeters are given in the standards produced by the International Electrotechnical Commission Working Group IEC SC45B/B8. A description is given of these standards and the use of electronic dosimeters as legal dosimeters is discussed. (author)

  2. Dosimeter

    International Nuclear Information System (INIS)

    Thomson, I.

    1986-01-01

    This invention relates to a dosimeter for measuring ionizing radiation, and particularly to a dosimeter using an insulated gate field effect transistor (IGFET) as a sensor, having substantially improved accuracy. An IGFET is a field effect transistor fabricated on a silicon substrate and having an oxide insulator between the gate electrode and the silicon substrate. The gate electrode can be either metal or polycrystalline silicon dioxide. This invention overcomes previously-noted problems with IGFET sensors - the variation of threshold voltage with temperature, their inherent zero offset which varies from wafer to wafer, and the zero drift in threshold voltage - by measuring the differential threshold between two IGFET sensors exposed to the same radiation, in which one is biased into its conducting region, and the other is biased either off or to a conducting level less than the first. The measured differential threshold voltage between the two transistors will be a measure of the gamma radiation dose

  3. Study of LiF:Mg,Ti and CaSO4:Dy dosimeters TL response to electron beams of 6 MeV applied to radiotherapy using PMMA and solid water phantoms

    International Nuclear Information System (INIS)

    Bravim, A.; Sakuraba, R.K.; Cruz, J.C.; Campos, L.L.

    2011-01-01

    The performance of CaSO 4 :Dy and LiF:Mg,Ti dosimeters to electron beams applied to radiotherapy was investigated. The TL response of these dosimeters was studied for 6 MeV electron beams using PMMA and Solid Water (SW) phantoms. The dosimeters were previously separated in groups according to their TL individual sensitivities to 60 Co gamma-radiation in air under electronic equilibrium conditions. After that, they were irradiated with 6 MeV electron doses of 0.1, 0.5, 1, 5 and 10 Gy using a linear accelerator Clinac 2100C Varian of Hospital Israelita Albert Einstein – HIAE. The electron beam irradiations were performed using a 10 × 10 cm 2 field size, 100 cm source-phantom surface distance and the dosimeters were positioned at the depth of maximum dose (1.2 cm). The TL readings were carried out between 24 and 32 h after irradiation using a Harshaw 3500 TL reader. The TL dose–response of both type of dosimeters and phantoms presented linear behavior on the electron dose range from 0.1 to 5 Gy CaSO 4 :Dy dosimeter is 21 times more sensitive than LiF:Mg,Ti, dosimeter commonly used in clinical dosimetry. The obtained results indicate that the performance of CaSO 4 :Dy dosimeters is similar to LiF:Mg,Ti dosimeters and this material can be an alternative dosimetric material to be used to clinical electron beams dosimetry.

  4. Copper doped borate dosimeters revisited

    Energy Technology Data Exchange (ETDEWEB)

    Alajerami, Y.S.M. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Department of Medical Radiography, Al-Azhar University, Gaza Strip, Palestine (Country Unknown); Hashim, S., E-mail: suhairul@utm.my [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Oncology Treatment Centre, Sultan Ismail Hospital, 81100 Johor Bahru (Malaysia); Ghoshal, S.K. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Bradley, D.A. [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Mhareb, M. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Saleh, M.A. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); National Atomic Energy Commission (NATEC), Sana' a (Yemen)

    2014-11-15

    We render a panoramic overview on copper (Cu) doped borate dosimeters. Preparing a dosimeter by mixing specific materials with precise weights and methods is a never-ending quest. The recommended composition is highly decisive for accurate estimation of the absorbed dose, prediction of the biological outcome, determination of the treatment dose for radiation therapy and facilitation of personal monitoring. Based on these principles, the proposed dosimeter must cover a series of dosimetric properties to realize the exact results and assessment. The doped borate dosimeters indeed demonstrate attractive thermoluminescence (TL) features. Several dedicated efforts are attempted to improve the luminescence properties by doping various transition metals or rare-earth elements. The Cu ion being one of the preferred activators shows excellent TL properties as revealed via detail comparison with other dosimeters. Two oxide states of Cu (Cu{sup +} and Cu{sup ++}) with reasonable atomic number allow easy interaction with boron network. Interestingly, the intrinsic luminescent centers of borate lattice are in cross linked with that of Cu{sup +} ions. Thus, the activation of borate dosimeter with Cu ions for the enhancement of the TL sensitivity is recognized. These dosimeters reveal similar glow curves as the standard TLD-100 (LiF:Mg,Ti) one irrespective of the use of modifiers and synthesis techniques. They display high sensitivity, low fading, dose response linearity over wide range and practical minimum detectable dose. Furthermore, the effective atomic number being the most beneficial aspect (equivalent to that of human tissue) of borate dosimeters do not show any change due to Cu ion activations. The past development, major challenges, excitement, applications, recent progress and the future promises of Cu doped borate TL dosimeters are highlighted. - Highlights: • The manuscript gives a panoramic overview on copper doped borate dosimeters. • Cu ions activated

  5. Copper doped borate dosimeters revisited

    International Nuclear Information System (INIS)

    Alajerami, Y.S.M.; Hashim, S.; Ghoshal, S.K.; Bradley, D.A.; Mhareb, M.; Saleh, M.A.

    2014-01-01

    We render a panoramic overview on copper (Cu) doped borate dosimeters. Preparing a dosimeter by mixing specific materials with precise weights and methods is a never-ending quest. The recommended composition is highly decisive for accurate estimation of the absorbed dose, prediction of the biological outcome, determination of the treatment dose for radiation therapy and facilitation of personal monitoring. Based on these principles, the proposed dosimeter must cover a series of dosimetric properties to realize the exact results and assessment. The doped borate dosimeters indeed demonstrate attractive thermoluminescence (TL) features. Several dedicated efforts are attempted to improve the luminescence properties by doping various transition metals or rare-earth elements. The Cu ion being one of the preferred activators shows excellent TL properties as revealed via detail comparison with other dosimeters. Two oxide states of Cu (Cu + and Cu ++ ) with reasonable atomic number allow easy interaction with boron network. Interestingly, the intrinsic luminescent centers of borate lattice are in cross linked with that of Cu + ions. Thus, the activation of borate dosimeter with Cu ions for the enhancement of the TL sensitivity is recognized. These dosimeters reveal similar glow curves as the standard TLD-100 (LiF:Mg,Ti) one irrespective of the use of modifiers and synthesis techniques. They display high sensitivity, low fading, dose response linearity over wide range and practical minimum detectable dose. Furthermore, the effective atomic number being the most beneficial aspect (equivalent to that of human tissue) of borate dosimeters do not show any change due to Cu ion activations. The past development, major challenges, excitement, applications, recent progress and the future promises of Cu doped borate TL dosimeters are highlighted. - Highlights: • The manuscript gives a panoramic overview on copper doped borate dosimeters. • Cu ions activated technique in borate

  6. Measurement of the reduction of terrestrial gamma-ray dose rates by the snow cover using TL-dosimeters

    International Nuclear Information System (INIS)

    Sakamoto, Ryuichi; Saito, Kimiaki; Nagaoka, Toshi; Tsutsumi, Masahiro; Moriuchi, Shigeru

    1990-12-01

    The objective of the investigation is to make clear the effect of the snow cover on environmental gamma-ray field. The reduction in the natural terrestrial gamma-ray dose rate due to snow cover was measured by TL-dosimeters. The measurements were performed in autumn before snowfall and in winter from September 1987 through March 1988 in Nagaoka city, Niigata prefecture. The dosimeters were set at four points, both outside and inside of the houses, for three months. The penetration factors (ratios of terrestrial gamma-ray dose accumulated during snow covered period to those during snow free period) were 0.54-0.67 in the open field, and 0.73-0.95 in the houses. According to theoretical calculation by the Monte Carlo method and the published snowfall data, the corresponding penetration factor was estimated at 0.54 in an ideal open field. As a result, the measured penetration factors were larger than calculated one by 24 % at maximum. The variation of dose rate inside houses by the difference of the amount of snow fall has been investigated. In general, though the amount of snow fall changes every year, dose rates inside the house were proved to be affected little by them. And, the optimum value of snow density which adapted for inference of penetration factor was found to be 0.3 g/cm 3 . The penetration factors inferred from snowdepth data for the year distributed between 0.6 and 1.0 in winter from November 1985 through April 1986 in Niigata prefecture. (author)

  7. Exfoliated graphite with graphene flakes as potential candidates for TL dosimeters at high gamma doses.

    Science.gov (United States)

    Ortiz-Morales, A; López-González, E; Rueda-Morales, G; Ortega-Cervantez, G; Ortiz-Lopez, J

    2018-06-06

    Graphite powder (GP) subjected to microwave radiation (MWG) results in exfoliation of graphite particles into few-layered graphene flakes (GF) intermixed with partially exfoliated graphite particles (PEG). Characterization of MWG by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Raman spectroscopy reveal few-layer GF with sizes ranging from 0.2 to 5 µm. Raman D, G, and 2D (G') bands characteristic of graphitic structures include evidence of the presence of bilayered graphene. The thermoluminescent (TL) dosimetric properties of MWG are evaluated and can be characterized as a gamma-ray sensitive and dose-resistant material with kinetic parameters (activation energy for the main peak located at 400 and 408 K is 0.69 and 0.72 eV) and threshold dose (~1 kGy and 5 kGy respectively). MWG is a low-Z material (Z eff = 6) with a wide linear range of TL dose-response (0.170-2.5 kGy) tested at doses in the 1-20 kGy range with promising results for applications in gamma-ray dosimetry. Results obtained in gamma irradiated MWG are compared with those obtained in graphite powder samples (GP) without microwave treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Dosimetric characterization and identification of TL defect centres in sand for its application in sludge irradiators as an in situ dosimeter

    International Nuclear Information System (INIS)

    Benny, P.G.; Shah, M.R.; Sabharwal, S.; Bhatt, B.C.; Gundu Rao, T.K.

    2003-08-01

    The report presents investigations that have been carried out to establish a method for the routine/ periodic dosimetry for Sludge Hygienisation Research Irradiator (SHRI) facility set up at Baroda (India) for disinfection of liquid sewage sludge in bulk quantity. For this purpose, the possibility of using the sand, one of the components of inorganic matter found in sewage sludge, directly as a TL dosimeter has been explored. The report is presented in two parts. Part 1 presents dosimetric characterization of sand for its application as an in situ dosimeter. A review on various sewage sludge irradiators operating in the world and the different dosimetric techniques used for these facilities are briefly described. In the present studies, in order to investigate the thermoluminescence properties of sand, it was separated from the sewage sludge by an extensive cleaning procedure. Part 1 also describes the procedure for separation of sand from sewage sludge, study on its TL properties, dosimetric characterization of sand and application of cleaned sand collected at the outlet of the SHRI facility for estimating radiation absorbed dose imparted to the sludge during its disinfection as well as for determining distribution of dose for an irradiated sludge batch. A new method by using phototransferred thermoluminescence (PTTL) in quartz separated from sand has been explored for high-level gamma dosimetry. Part 2 of the report presents sensitization properties of TL peaks and study of TL defect centres in quartz. It describes the results on pre-dose sensitization of 220 degC and 110 degC TL peaks in the quartz samples separated from sand. From the TL and ESR studies, a mechanism for TL sensitization has been suggested, which involves the role of competing traps and E I - centres in the sensitization process. The paramagnetic radicals formed in quartz samples after gamma irradiation by using ESR technique have been briefly described. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-15

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

  10. Advances in the development of Cr-39 based neutron dosimeters

    International Nuclear Information System (INIS)

    Hadlock, D.E.; Parkhurst, M.A.

    1987-12-01

    A combination thermoluminescent dosimeter (TLD) and track etch dosimeter (TED), which can be used for detecting neutrons over a wide energy range, has been developed through recent research in passive neutron dosimetery. This dosimeter uses Li-600 TLDs to detect thermal and low energy neutrons reflected from the body, and the TED polymer of CR-39, to detect fast neutrons from proton recoil interactions with the polyethylene radiator or with CR-39 itself. Some form of the combination dosimeter is currently in use at several US Department of Energy (DOE) facilities, and its use is expected to expand over the next year to include all DOE facilities where significant neutron exposures may occur. The extensive research conducted on the TED component over the past six years has continually focused on material improvements, reduction in processing time and dosimeter handling, and ease of sample readout with the goal of automating the process as much as possible. 1 fig

  11. Development of tailor-made silica fibres for TL dosimetry

    International Nuclear Information System (INIS)

    Bradley, D.A.; Abdul Sani, Siti F.; Alalawi, Amani I.; Jafari, S.M.; Noor, Noramaliza M.; Hairul Azhar, A.R.; Mahdiraji, Ghafour Amouzad; Tamchek, Nizam; Ghosh, S.; Paul, M.C.; Alzimami, Khalid S.; Nisbet, A.; Maah, M.J.

    2014-01-01

    The Ge dopant in commercially available silica optical fibres gives rise to appreciable thermoluminscence (TL), weight-for-weight offering sensitivity to MV X-rays several times that of the LiF dosimeter TLD100. The response of these fibres to UV radiation, X-rays, electrons, protons, neutrons and alpha particles, with doses from a fraction of 1 Gy up to 10 kGy, have stimulated further investigation of the magnitude of the TL signal for intrinsic and doped SiO 2 fibres. We represent a consortium effort between Malaysian partners and the University of Surrey, aimed at production of silica fibres with specific TL dosimetry applications, utilizing modified chemical vapour deposition (MCVD) doped silica–glass production and fibre-pulling facilities. The work is informed by defect and dopant concentration and various production dependences including pulling parameters such as temperature, speed and tension; the fibres also provide for spatial resolutions down to <10 µm, confronting many limitations faced in use of conventional (TL) dosimetry. Early results are shown for high spatial resolution (∼0.1 mm) single-core Ge-doped TL sensors, suited to radiotherapy applications. Preliminary results are also shown for undoped flat optical fibres of mm dimensions and Ge-B doped flat optical fibres of sub-mm dimensions, with potential for measurement of doses in medical diagnostic applications. - Highlights: • Optical fibres tailor-made for TL dosimetry. • Sensitive to diagnostic as well as therapy doses in medicine. • Preform and fibre pulling facilities. • Relative TL and EPR measurements

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

  13. Development of a multichannel dosimeter for radiotherapy

    International Nuclear Information System (INIS)

    Menezes, Claudio Jose Mesquita

    2000-06-01

    In radiotherapy, verification of the patient dose is of great important for the success of the treatment. Uncertainties in the evaluation of this dose can produce serious complications such as the loss of the control of the disease and damage to normal tissue. Semiconductor detectors present advantages over other types of radiation detectors such as ionization chambers and thermoluminescent dosimeters including small dimensions, high sensitivity and fast response. In this work, a multichannel dosimetric system is linear with dose, for a 6 MV x-ray beam and also with a beam of cobalt-60 gamma rays. The coefficients of determination of the calibration curves were better then 0,9998 in all cases. The four sensors presented similar response with the dose for different field sizes. The variation of the response was smaller than 1%. In a related study, depth dose was measured, and the results showed a good agreement compared to theoretical values. The angular response of the detectors showed a variation of 7% for angles of 45 deg C. Using the Anderson Random phantom, dose at the isocenter was determined from measurements of the surface dose. From the results obtained it can be concluded that the dosimetric system developed is adequate for the evaluation of many parameters in radiation fields used in radiotherapy. This system can be used to measure the patient entrance dose under treatment conditions, and the equipment can be used in the radiotherapy quality assurance program. (author)

  14. Electrochemical development of particle tracks in CR-39 polymer dosimeter

    International Nuclear Information System (INIS)

    Hadlock, D.E.; Parkhurst, M.A.; Yang, C.S.; Groeger, J.; Johnson, J.R.; Huang, S.J.

    1985-09-01

    Electrochemical etching of CR-39 polymeric track etch neutron detectors results in proton-recoil tracks can be distinguished from background tracks much better than tracks developed solely by chemical etching. A newly designed and constructed electrochemical etching apparatus allows large numbers of dosimeters to be processed simultaneously with consistent results. Many processing systems have been developed for chemical and electrochemical etching of the track etch dosimeters. Three systems specifically show great promise and are being studied extensively

  15. 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).

  16. Storage Telemetry of Radionuclide Tracers by Implantable Thermoluminescent Dosimeters

    DEFF Research Database (Denmark)

    Bojsen, J.; Møller, U.; Christensen, Poul

    1977-01-01

    A storage telemetrical method using thermoluminescent (TL) dosimeters for long-term measurements of incorporated radioactive substances in unrestrained rats has been developed. The system has been used in combination with radiotelemetrical registration of the circadian temperature rhythm. By sequ...

  17. Design and development of a PMOSFET gamma ray dosimeter

    International Nuclear Information System (INIS)

    Khanna, V.K.; Kumar, A.; Gupta, R.P.; Pandya, A.; Roy, Rajesh

    2005-01-01

    A P-channel MOSFET chip has been designed for detection of gamma radiations. The chip consists of three MOSFETs of different geometrical parameters for achieving sensitivity to low and high dose ranges. One of the MOSFET structures has a closed geometry to reduce the leakage current. The developed dosimeter being a MOSFET, its IC (Integrated Circuit)-compatibility helps in easy interfacing with readout circuitry. The dosimeter fabrication process is based on metal-gate MOSFET technology with thick gate oxide to increase the effective number of electron-hole pairs generated by the gamma rays impinging on the device. The process for the chip realization has been designed and simulated to achieve the required impurity diffusion profile. The chip has been fabricated using the above process and electrically characterized. The device has been exposed to gamma ray source and its characteristics measured. The change in threshold voltage of the MOSFET after exposure has been used to calculate the sensitivity of the device. The developed dosimeter has potential applications in personnel dosimetry and cancer treatment. This paper describes the basic detection mechanism of the MOSFET, the design approach, and fabrication process of the MOSFET dosimeter. (author)

  18. Development of low background CsI(Tl) and NaI(Tl) crystals for WIMP search

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Su [Department of Physics, Ewha Womans University, Seoul 120-750 (Korea, Republic of)

    2015-08-17

    We have developed low background CsI(Tl) and NaI(Tl) crystals to search for weakly interacting massive particles as well as to verify the origin of the annual modulation signal observed by the DAMA/LIBRA experiment. Extensive studies about the contamination mechanisim of {sup 137}Cs in CsI powder lead to the growth of ultra-low-background CsI(Tl) crystals. Similar approaches for NaI(Tl) crystals have been applied to reduce internal backgrounds to less than 0.5 counts/kg/day/keV. Status and understanding of backgrounds and background reduction in NaI(Tl) crystals will be discussed.

  19. US progress on the development of CR-39 based neutron dosimeters

    International Nuclear Information System (INIS)

    Hadlock, D.E.

    1987-06-01

    Historically at US nuclear facilities, two types of personnel neutron dosimeters have been in routine use: nuclear track emulsion-Type A (NTA) film and thermoluminescent dosimeter (TLD)-albedo. Both of these dosimeters have energy-dependent responses. Therefore, the neutron energy spectra must be known, to interpret the dosimeter results properly. A new state-of-the-art dosimetry system has been developed within the US Department of Energy (US DOE) Personnel Neutron Dosimeter Evaluation and Upgrade Program. This system is called the combination thermoluminescent dosimeter/track etch dosimeter (TLD/TED). This paper briefly describes US DOE research currently being conducted to further enhance the TED portion of the combination TLD/TED system. The research areas involved include dose sensitivity, neutron energy range, specialized radiators, self-developing dosimeters, and neutron spectrometry. 1 fig., 1 tab

  20. Microcomputer control of automated TL reader

    International Nuclear Information System (INIS)

    Bjarland, B.

    1980-01-01

    An automatic TL reader has been developed for use within a TLD based personal monitoring service. A 6800 based microcomputer is used for system control, operator communication, calibration and checking of reader operation, and for output of data. The dosimeter identity code is printed in human readable characters on the dosimeter card, and is read by using an optical character recognition unit. The code may include individual sensitivity correction coefficients for the TL chips on the card. The chips are heated with hot nitrogen gas and the thermoluminescence is recorded by a photomultiplier tube circuit, the gain and offset of which are continuously monitored and, when necessary, adjusted, to maintain calibration. The reader may operate in any of seven modes, i.e. reading modes for three types of dosimeters, semiautomatic modes for production of the three types of dosimeters, and a monitor mode. (Auth.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-15

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

  2. Developing a biological dosimeter based on mitochondrial DNA

    Energy Technology Data Exchange (ETDEWEB)

    Adams, S; Carlisle, S M; Unrau, P; Deugau, K V [Atomic Energy of Canada Ltd., Chalk River, ON (Canada)

    1996-12-31

    Direct measurement of deoxyribonucleic acid (DNA) damage from ionizing radiation may be advantageous in determining radiation radiation exposures and assessing their effects on atomic radiation workers. The mitochondrial DNA molecule is one potential cellular DNA target which is: fully defined and sequenced; present in many copies per cell; not vital to cellular survival; and less subject to DNA repair than nuclear DNA. A method is described to isolate and analyse normal mitochondrial DNA. We describe the developments needed to determine DNA damage in mitochondrial DNA. The target is to make a biological dosimeter. (author). 6 refs., 3 figs.

  3. Developing a biological dosimeter based on mitochondrial DNA

    International Nuclear Information System (INIS)

    Adams, S.; Carlisle, S.M.; Unrau, P.; Deugau, K.V.

    1995-01-01

    Direct measurement of deoxyribonucleic acid (DNA) damage from ionizing radiation may be advantageous in determining radiation radiation exposures and assessing their effects on atomic radiation workers. The mitochondrial DNA molecule is one potential cellular DNA target which is: fully defined and sequenced; present in many copies per cell; not vital to cellular survival; and less subject to DNA repair than nuclear DNA. A method is described to isolate and analyse normal mitochondrial DNA. We describe the developments needed to determine DNA damage in mitochondrial DNA. The target is to make a biological dosimeter. (author). 6 refs., 3 figs

  4. Challenges to Disciplinary Knowing and Identity: Experiences of Scholars in a SoTL Development Program

    Science.gov (United States)

    Miller-Young, Janice E.; Yeo, Michelle; Manarin, Karen

    2018-01-01

    Faculty members from five years of an annual Scholarship of Teaching and Learning (SoTL) development program were invited to participate in a study about the impact of SoTL on their teaching, scholarship, and career trajectory. During semi-structured interviews, many expressed feeling discomfort during their journey into SoTL. A qualitative…

  5. Development of a miniaturized watch-type dosimeter using a silicon printed-circuit board

    International Nuclear Information System (INIS)

    Ishikura, Takeshi; Sakamaki, Tsuyoshi; Matsumoto, Iwao; Aoyama, Kei; Nakamura, Takashi

    2008-01-01

    The electrical personal dosimeter using a silicon semiconductor sensor has the advantage of real time response and alarm function, which can prevent unexpected over-exposure. We tried to develop a miniaturized watch-type dosimeter by incorporating the silicon semiconductor sensor on a silicon printed-circuit board. Thin film resistors, capacitors and wiring patterns are formed on a downsized printed-circuit board. Electronic parts including transistors are mounted by soldering on the silicon printed-circuit board. The dosimeter is further miniaturized by downsizing the amplifier circuit, the semiconductor radiation sensor, the power supply circuit, setting parts and alarm part. The performance of the developed dosimeter was evaluated with respect to the gamma-ray spectra, angular dependence and linearity to dose equivalent rate, and it was confirmed that this dosimeter has the performance equivalent to a commercially available electrical personal dosimeter. (author)

  6. Development of a gamma dosimeter using a photodiode

    International Nuclear Information System (INIS)

    Melo, F.A. de.

    1988-05-01

    In the last years, the application of semiconductor detectors in radiation spectroscopy and dosimetry has increased. Silicon diodes have found utility in radiation dosimetry principally because a diode produces a current approximately 18000 times larger than of an ionization chamber of an equal sensitive volume. As the characteristics of the semiconductor detectors are the same as the common photodiode, a gamma dosimeter using this type of electronic component was developed. The photodiode SFH206 operating in photovoltaic mode was used. An electrometric unit was constructed to measure the current generated in this detector. The results obtained showed: the response of the photodiode was linear with the dose and that variation of 40 degrees in the incidence angle of the radiation caused a variation of 5% in the dose determination; the response reproducibility of the photodiode was studied, and the results showed that the variation coefficient is smaller than 0,02%; the small dimension of the silicon photodiode recommend its use as a gamma dosimeter for medical applications. (author). 19 refs, 32 figs, 1 tab

  7. Review of four novel dosimeters developed for use in radiotherapy

    Science.gov (United States)

    Metcalfe, P.; Quinn, A.; Loo, K.; Lerch, M.; Petasecca, M.; Wong, J.; Hardcastle, N.; Carolan, M.; McNamara, J.; Cutajar, D.; Fuduli, I.; Espinoza, A.; Porumb, C.; Rosenfeld, A.

    2013-06-01

    Centre for Medical Radiation Physics (CMRP) is a research strength at the University of Wollongong, the main research theme of this centre is to develop prototype novel radiation dosimeters. Multiple detector systems have been developed by Prof Rosenfelds' group for various radiation detector applications. This paper focuses on four current detector systems being developed and studied at CMRP. Two silicon array detectors include the magic plate and dose magnifying glass (DMG), the primary focus of these two detectors is high spatial and temporal resolution dosimetry in intensity modulated radiation therapy (IMRT) beams. The third detector discussed is the MOSkinTM which is a high spatial resolution detector based on MOSFET technology, its primary role is in vivo dosimetry. The fourth detector system discussed is BrachyView, this is a high resolution dose viewing system based on Medipix detector technology.

  8. LLL development of a combined etch track: albedo dosimeter

    International Nuclear Information System (INIS)

    Griffith, R.V.; Fisher, J.C.; Harder, C.A.

    1977-01-01

    The addition of polycarbonate sheet to albedo detectors for electrochemical etching provides a simple, inexpensive way to reduce the spectral sensitivity of the personnel dosimeter without losing the albedo features of sensitivity and ease of automation. The ECEP technique also provides the dosimetrist with the potential for identifying conditions of body orientation that might otherwise lead to significant error in dosimeter evaluation

  9. Developing SoTL through Organized Scholarship Institutes

    Directory of Open Access Journals (Sweden)

    Elizabeth Marquis

    2015-12-01

    Full Text Available The need to further integrate SoTL into college and university cultures has been discussed relatively frequently in recent teaching and learning literature. While a number of useful strategies to assist in this task have been advanced, one especially promising suggestion is the development of organized, institutionally-recognized scholarship institutes. Centres or units of this sort have been created at higher education institutions in a number of countries, but little published information currently exists about the design of these institutes or the experiences of individuals affiliated with them. To that end, the present study sought to examine the perceived benefits, challenges and design features of teaching and learning scholarship institutes at research-intensive universities worldwide. A website scan and a survey of individuals affiliated with these units were used to collect qualitative and quantitative data of relevance to the research questions. Based on the findings, and on ideas from the existing research institute and scholarship of teaching and learning literatures, a series of recommendations for individuals and campuses interested in developing effective SoTL institutes are provided.

  10. Development of surgical gamma probes with TlBr semiconductors and CsI(Tl) scintillators crystals

    International Nuclear Information System (INIS)

    Costa, Fabio Eduardo da

    2006-01-01

    Radio guided surgery, using probes with radiation detectors, has been prominence in the medical area in the last decade. This technique consists in injecting a radioactive substance to concentrate in tumour and assist the localization during the surgical procedure. The radio guided surgeries allowing the identification of lymph node has revolutioned the behavior of tumour in initial stadium when are being spread by lymphatic way. The conditions imposed to the surgery due the proximity between some lymph nodes, demands of the probes, a small diameters and capacity of individual identification of these lymph nodes radiolabelled by a specific tracer. The international market supplies these probes with CdTe semiconductors and scintillators, but there is some time lack a promptly technical assistance in the Brazilian market. This work developed probes with national technology, using CsI(Tl) scintillators crystals and, in substitution to CdTe crystals semiconductors, the TlBr crystal, that is a new semiconductor detector in a world-wide development, with advantages in relation to the CdTe. Both crystals have been grown in IPEN. All the necessary electronics, specially, the preamplifier, that was also a restrictive factor for development of these types of probe in the country, have been developed with components found in the national market. Systematic measures of spatial resolution, spatial selectivity, maximum sensitivity and quality of the shielding have been carried the probes development. The results have shown that the probes, one with the CsI(Tl) crystal and another with TlBr semiconductor presented the requested performance in the international literature for radio guided probes. (author)

  11. How Experienced SoTL Researchers Develop the Credibility of Their Work

    Directory of Open Access Journals (Sweden)

    Jennie Billot

    2017-03-01

    Full Text Available Teaching and learning research in higher education, often referred to as the Scholarship of Teaching and Learning (SoTL, is still relatively novel in many academic contexts compared to the mainstay of disciplinary research. One indication of this is the challenges those who engage in SoTL report in terms of how this work is valued or considered credible amongst disciplinary colleagues and in the face of institutional policies and practices. This paper moves beyond the literature that describes these specific challenges to investigate how 23 experienced SoTL researchers from five different countries understood the notion of credibility in relationship to their SoTL research and how they went about developing credibility for their work. Semi-structured interviews were facilitated and analyzed using inductive analysis. Findings indicate that notions of credibility encompassed putting SoTL research into action and building capacity and community around research findings, as well as gaining external validation through traditional indicators such as publishing. SoTL researchers reported a variety of strategies and approaches they were using, both formal and informal, to develop credibility for their work. The direct focus of this paper on credibility of SoTL work as perceived by experienced SoTL researchers, and how they go about developing credibility, is a distinct contribution to the discussions about the valuing of SoTL work.

  12. Development of neutron dosimeter using CR-39 for measurement of ambient dose equivalent

    International Nuclear Information System (INIS)

    Maki, Daisuke; Shinozaki, Wakako; Ohguchi, Hiroyuki; Yamamoto, Takayoshi; Nakamura, Takayoshi

    2010-01-01

    A CR-39 has good advantages such as cumulative type dosimeter, small fading effect and gamma-ray insensitive. Therefore, we developed the wide energy-range environmental neutron dosimeter using eight CR-39s for area monitoring in this study. This dosimeter is made of octagonal columnar polyethylene block which height is 60 mm and bottom side is 25 mm. The dosimeter contains two types of CR-39s for fast neutron detection and slow neutron detection. Four CR-39s for fast neutron detection are used for detection of recoil protons produced by H (n, p) reactions. Four CR-39s for slow neutron detection are used with boron nitride converter to detect alpha-rays produced by 10 B (n, α) 7 Li reactions. Ambient dose equivalent is obtained by adding the number of etch-pits observed in four CR-39s for fast neutron detection to the number of etch-pits observed in four CR-39s for slow neutron detection with appropriate constants respectively. Dosimeters were irradiated with some energetic neutrons and evaluated results of ambient dose equivalent were compared with results from neutron transport calculations. Energy response of dosimeter shows good agreement with neutron fluence to ambient dose equivalent conversion coefficients. Directional dependence of dosimeter is at the same level as the rem-counter. (author)

  13. Development and characterization of real-time wide-energy range personal neutron dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Takashi; Tsujimura, Norio (Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center); Yamano, Toshiya; Suzuki, Toshikazu; Okamoto, Eisuke

    1994-04-01

    The authors developed a real-time personal neutron dosimeter which could give neutron dose equivalent over wide energy region from thermal to 10 odd MeV by using 2 silicon detectors, fast neutron sensor and slow neutron sensor. The energy response of this dosimeter was evaluated under thermal neutron field, monoenergetic neutron field between 200 keV and 15 MeV, and moderated [sup 252]Cf neutron field. The neutron dose equivalent was estimated by adding neutron dose equivalent below 1 MeV given by slow neutron sensor and that above 1 MeV by fast neutron sensor. It was verified from various field tests that this dosimeter is able to give neutron dose equivalent within a factor of 2 margin of accuracy in reactor, accelerator, fusion research and nuclear fuel handling facilities. This dosimeter has more than one order higher sensitivity than conventional personal neutron dosimeters and is insensitive to [gamma]-rays up to about 500 mSv/h. This dosimeter will soon be commercially available as a personal dosimeter which gives neutron and [gamma]-ray dose equivalents simultaneously by installing [gamma]-ray silicon sensor. (author).

  14. Development of bead-type radiophotoluminescence glass dosimeter applicable to various purposes

    International Nuclear Information System (INIS)

    Sato, F.; Toyota, Y.; Maki, D.; Zushi, N.; Kato, Y.; Yamamoto, T.; Iida, T.

    2013-01-01

    Bead-type radiophotoluminescence (RPL) glass dosimeters were well fabricated with a gas-particle jet flame system for glass melting-cooling process. A rod of silver-activated phosphate glass was pulverized into micrometer-size particles. Spherical glass particles were formed from the pulverized glass particles in the high-temperature jet flame owing to the surface tension of the glass material. Some groups of spherical glass particles were irradiated with X-rays and their RPL was demonstrably observed for their exposure to UV light. A flexible RPL glass sheet was also made of bead-type RPL glass dosimeters and was useful for radiation imaging. Bead-type RPL glass dosimeters are expected to be used for dose monitoring in highly radioactively-contaminated area. -- Highlights: ► We developed bead-type radiophotoluminescence glass dosimeters. ► Bead-type glass RPL dosimeters are satisfactorily used as radiation dosimeters. ► A flexible RPL glass sheet is made of bead-type RPL glass dosimeters

  15. Radiation dosimeters for medical use

    International Nuclear Information System (INIS)

    Risticj, S. Goran

    2013-01-01

    The several personal radiation dosimeter types for medical use, which look like promising for this kind of application, as pMOS (RADFET) dosimeter, direct ion storage (DIS) dosimeters, thermoluminescent (TL) and optically stimulated luminescent (OSL) dosimeters, are described, and their advantages and disadvantages are analyzed. The p-channel metal-oxide-semiconductor (pMOS) dosimetric transistors allow dose measurements in vivo in real time, and they are especially important for radiotherapy. Direct ion storage (DIS) dosimeters are a hybrid of ion chamber and floating gate MOSFETs (FGMOSFETs), show very high sensitivity. Radiative processes that happen during the exposure of crystal to radiation are classified as prompt luminescence or radioluminescence (RL). In the case of an emission during stimulation, this phenomenon is referred to thermoluminescence or optically stimulated luminescence depending on whether the stimulation source is heat or light. TL and OSL dosimeters are natural or synthetic materials, which the intensity of emitted light is proportional to the irradiation dose. (Author)

  16. 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

  17. An in-house developed resettable MOSFET dosimeter for radiotherapy.

    Science.gov (United States)

    Verellen, Dirk; Van Vaerenbergh, Sven; Tournel, Koen; Heuninckx, Karina; Joris, Laurent; Duchateau, Michael; Linthout, Nadine; Gevaert, Thierry; Reynders, Truus; Van de Vondel, Iwein; Coppens, Luc; Depuydt, Tom; De Ridder, Mark; Storme, Guy

    2010-02-21

    The purpose of this note is to report the feasibility and clinical validation of an in-house developed MOSFET dosimetry system and describe an integrated non-destructive reset procedure. Off-the-shelf MOSFETs are connected to a common PC using an 18 bit/analogue-input and 16 bit/output data acquisition card. A reading algorithm was developed defining the zero-temperature-coefficient point (ZTC) to determine the threshold voltage. A wireless interface was established for ease of use. The reset procedure consists of an internal circuit generating a local heating induced by an electrical current. Sensitivity has been investigated as a function of bias voltage (0-9 V) to the gate. Dosimetric properties have been evaluated for 6 MV and 15 MV clinical photon beams and in vivo benchmarking was performed against thermoluminescence dosimeters (TLD) for conventional treatments (two groups of ten patients for each energy) and total body irradiation (TBI). MOSFETS were pre-irradiated with 20 Gy. Sensitivity of 0.08 mV cGy(-1) can be obtained for 200 cGy irradiations at 5 V bias voltage. Ten consecutive measurements at 200 cGy yield a SD of 2.08 cGy (1.05%). Increasing the dose in steps from 5 cGy to 1000 cGy yields a 1.00 Pearson correlation coefficient and agreement within 2.0%. Dose rate dependence (160-800 cGy min(-1)) was within 2.5%, temperature dependence within 2.0% (25-37 degrees C). A strong angular dependence has been observed for gantry incidences exceeding +/-30 degrees C. Dose response is stable up to 50 Gy (saturation occurs at approximately 90 Gy), which is used as threshold dose before resetting the MOSFET. An average measured-over-calculated dose ratio within 1.05 (SD: 0.04) has been obtained in vivo. TBI midplane-dose assessed by entrance and exit dose measurements agreed within 1.9% with ionization chamber in phantom, and within 1.0% with TLD in vivo. An in-house developed resettable MOSFET-based dosimetry system is proposed. The system has been validated

  18. Development of diffusion-based radon daughter dosimeters

    International Nuclear Information System (INIS)

    Phillips, C.R.; Khan, A.; Leung, H.

    1983-07-01

    The objective of this work is to investigate the possible application of the mechanisms of thermophoresis and electrostatic collection via electrets to the collection of radon daughters with reference to personal alpha dosimeters for use in uranium mines. The potential advantage accruing from adoption of either one of these collection mechanisms is that collection is passive and does not depend upon the use of a pump (active), and is, therefore, intrinsically much more reliable

  19. Development of new chemical dosimeter for low dose range

    International Nuclear Information System (INIS)

    Mhatre, Sachin G.V.; Adhikari, S.

    2012-01-01

    Accurate measurement of low dose radiation in complex systems is of utmost importance in radiation biology and related areas. Ferrous Benzoic acid Xylenol orange (FBX) system is being widely used for measurement of low dose gamma radiation because of its reproducibility and precision. However, an additional step, i.e., dissolution of benzoic acid in water at higher temperature followed by cooling at room temperature is involved for the preparation of this dosimeter. This makes it inconvenient as a ready to use dosimeter. In the present work, the organic molecule, sorbitol has been used for measurement of low doses of radiation. The advantages of using sorbitol are its ready availability and instantaneous water solubility. Owing to its dissolution at room temperature, possible errors those are involved in calculation of dose due to thermal oxidation of ferrous ions during preparation of the FBX dosimetric solution could be made insignificant in the proposed dosimeter. In the present system, sorbitol acts as radiolytic sensitizer for the oxidation of ferrous ion, and xylenol orange forms a 1:1 complex specifically with ferric ions. Thus, the analytical detection limit of ferric ions is enhanced compared to other systems. Final composition of the dosimetric solution is; 0.5 mol/m 3 xylenol orange, 10 mol/m 3 sorbitol and 0.2 mol/m 3 ferrous ion in 50 mol/m 3 sulfuric acid. Radiolytic sensitization in combination with analytical enhancement of the ferrous based system, allows us to measure radiation dose in the range of 0.05 Gy–12 Gy with ease and high reproducibility.

  20. Development of a new dosimeter of EPR based on lactose

    International Nuclear Information System (INIS)

    Cruz C, L.; Torijano C, E.; Azorin N, J.; Aguirre G, F.; Cruz Z, E.

    2014-08-01

    50 years have passed since was proposed using the amino acid alanine as dosimeter advantage the phenomenon of electron paramagnetic resonance (EPR); this dosimetric method has reached a highly competitive level regarding others dosimetry classic methods, for example the thermoluminescence or the use of Fricke dosimeters, to measure high dose of radiation. In this type of materials, the free radicals induced by the radiation are stable and their concentration is proportional to the absorbed dose may be determined by the amplitude pick to pick of the first derived of the EPR absorption spectrum. The obtained results studying the EPR response of lactose tablets elaborated in the Universidad Autonoma Metropolitana, Unidad Iztapalapa are presented. The tablets were irradiated with gamma radiation of 60 Co in the irradiator Gamma beam 651-Pt of the Instituto de Ciencias Nucleares de la Universidad Nacional Autonoma de Mexico to a dose rate of 8 kGy-h -1 and their EPR response in a EPR spectrometer e-scan Bruker. The obtained response in function of the dose was lineal in the interval of 1 at 10 kGy. The lactose sensibility was compared with the l-alanine, used as reference, and the result was consistently 0.25 of this. Due to the linearity shown in the interval of used dose and their low production cost, we conclude that the lactose is a promissory option for the dosimetry of high dose of radiation. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-01-01

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

  2. Development and underground testing of the α dosimeter: a solid state electronic personal radiation dosimeter for uranium miners

    International Nuclear Information System (INIS)

    Parkinson, R.N.; Roze, V.; Shepherd, R.

    1981-01-01

    The αDOSIMETER is a complete, integrated system designed to monitor the immediate worksite of underground miners where the disintegration for radon daughters is a risk to the health of mining personnel. The dosimeter weighing little more than one pound is worn by each miner throughout the entire shift and is powered by the miner's cap lamp battery. After this integration period, the unit is connected to a reading network whereupon the day's data is dumped, calculated and stored. Beginning in July 1980, prototype units were subjected to vigorous underground testing in uranium mines in Canada and the United States and in tin mines in Cornwall, UK. The testing results are summarized and proposals advanced for a typical mine monitoring system utilizing the αDOSIMETER

  3. A comparative study of the thermoluminescent response to beta irradiation of CVD diamond and LiF dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Bogani, F. [Florence Univ. (Italy). Dipt. di Energetica; Borchi, E. [Florence Univ. (Italy). Dipt. di Energetica; Bruzzi, M. [Florence Univ. (Italy). Dipt. di Energetica; Leroy, C. [Florence Univ. (Italy). Dipt. di Energetica; Sciortino, S. [Florence Univ. (Italy). Dipt. di Energetica

    1997-04-01

    The thermoluminescent (TL) response of chemical vapour deposited (CVD) diamond films to beta irradiation has been investigated. A numerical curve-fitting procedure, calibrated by means of a set of LiF TLD100 experimental spectra, has been developed to deconvolute the complex structured TL glow curves. The values of the activation energy and of the frequency factor related to each of the TL peaks involved have been determined. The TL response of the CVD diamond films to beta irradiation has been compared with the TL response of a set of LiF TLD100 and TLD700 dosimeters. The results have been discussed and compared in view of an assessment of the efficiency of CVD diamond films in future applications as in vivo dosimeters. (orig.).

  4. A comparative study of the thermoluminescent response to beta irradiation of CVD diamond and LiF dosimeters

    Science.gov (United States)

    Bogani, F.; Borchi, E.; Bruzzi, M.; Leroy, C.; Sciortino, S.

    1997-02-01

    The thermoluminescent (TL) response of Chemical Vapour Deposited (CVD) diamond films to beta irradiation has been investigated. A numerical curve-fitting procedure, calibrated by means of a set of LiF TLD100 experimental spectra, has been developed to deconvolute the complex structured TL glow curves. The values of the activation energy and of the frequency factor related to each of the TL peaks involved have been determined. The TL response of the CVD diamond films to beta irradiation has been compared with the TL response of a set of LiF TLD100 and TLD700 dosimeters. The results have been discussed and compared in view of an assessment of the efficiency of CVD diamond films in future applications as in vivo dosimeters.

  5. A comparative study of the thermoluminescent response to beta irradiation of CVD diamond and LiF dosimeters

    International Nuclear Information System (INIS)

    Bogani, F.; Borchi, E.; Bruzzi, M.; Leroy, C.; Sciortino, S.

    1997-01-01

    The thermoluminescent (TL) response of chemical vapour deposited (CVD) diamond films to beta irradiation has been investigated. A numerical curve-fitting procedure, calibrated by means of a set of LiF TLD100 experimental spectra, has been developed to deconvolute the complex structured TL glow curves. The values of the activation energy and of the frequency factor related to each of the TL peaks involved have been determined. The TL response of the CVD diamond films to beta irradiation has been compared with the TL response of a set of LiF TLD100 and TLD700 dosimeters. The results have been discussed and compared in view of an assessment of the efficiency of CVD diamond films in future applications as in vivo dosimeters. (orig.)

  6. Reflecting on Institutional Support for SoTL Engagement: Developing a Conceptual Framework

    Science.gov (United States)

    Myatt, Paula; Gannaway, Deanne; Chia, Ivy; Fraser, Kym; McDonald, Jacquelin

    2018-01-01

    This paper considers the support required to develop Scholarship of Teaching and Learning (SoTL) capability across institutions. Rather than developing a checklist or a standardised audit approach, this paper describes the reflective journey taken by a group of academic developers who used strategies and structures previously identified in the…

  7. Development of real time personal neutron dosimeter with two silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, T.; Tsujimura, N. [Tohoku Univ., Cyclotron and Radioisotope Center, Aoba, Aramaki, Aoba-ku (Japan); Yamano, T. [Tokyo Factory, Fuji Electric Co. Ltd., Tokyo (Japan)

    1992-07-01

    We developed a real time personal neutron dosimeter by using two types of silicon p-n junction detectors, thermal neutron sensor and fast neutron sensor. The thermal neutron sensor which is {sup 10}B doped n-type silicon with a polyethylene radiator mainly counts neutrons of energy front thermal to I MeV, and the fast neutron sensor which is p-type silicon with a polyethylene radiator is sensitive to neutrons above I MeV. The neutron sensitivity measurements revealed that the dosimeter has a rather flat response for dose equivalent from thermal to 15 MeV, excluding a drop from 50 keV to I MeV. In order to get conversion factor from counts to dose equivalent as accurately as possible, we performed the field test of the dosimeter calibration in several neutron-generating fields. By introducing the two-group dose estimation method, this dosimeter can give the neutron dose equivalent within about 50% errors. (author)

  8. Dosimeter design specifications

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The combination dosimeter and security credential holder was developed as part of the effort involved to provide an automated readout and thermoluminescent dosimetry capability at Hanford. The holder is designed to accomodate the thermoluminescent dosimeter card, appropriate filters, the security credential and a snap type clip. The body of the holder is ABS plastic (acrylontrile-butadiene-styrene). The dosimeter holder and card is mold casted providing uniformity of construction

  9. Improving TL dosimetry for external radiotherapy

    International Nuclear Information System (INIS)

    Bustos, S.R.; Velez, G.; Rubio, M.

    1998-01-01

    Full text: In vivo thermoluminescence dosimetry (TLD) has always been one of the most accurate dosimetry method for external radiotherapy control, but the delay in the response is a well know drawback when it is applied. In this work we show some improvements and demonstrate that keeping the precision and accuracy of this technique, it is possible to obtain a response in few hours. Harshaw 4000 TL reader and LiF TLD-100 dosimeters, chips (3,1 x 3,1 x 0,9 mm 3 ) and rods (1 x 1 x 6 mm 3 ) have been used. The thermal treatment necessary to reuse the TLD is only 1h at 400 degree C, by using a glow curve analyser developed at the Ciemat (Spain), that allows a complete, prompt and precise identification of the individuals peaks. The dosimeters are periodically and individually calibrated. We also have study the factors contributing to the relation TL-dose like linearity, energy correction, directional response and fading. All those results are included into an Excel worksheet which automatically give us the dose resulting from the TL reading (peaks areas 4 and 5). The obtained uncertainty is better than 5%. The TLD already irradiated in radiotherapy institutions distant 30-40 Km from our centre can be read and analysed in about 3-4 hours. These facts render our methods rapid and allow a better control of radiotherapy treatment even if it is bi-fractionated. (author) [es

  10. Dose distribution assessment (comparison) in the target volume treated with VMAT given by the planning system and evaluated by TL dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Bravim, A.; Sakuraba, R.K.; Campos, L.L., E-mail: ambravim@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Gerencia de Metrologia das Radiacoes

    2015-07-01

    Volumetric-modulated arc therapy (VMAT) is a relatively new therapy technique in which treatment is delivered using a cone beam that rotates around the patient. The radiation is delivered in a continuous gantry rotation while the cone beam is modulated by the intertwining of dynamic multileaf collimators (MLCs). Studies of VMAT plans have shown reduction in the treatment delivery time and monitor units (MU) comparable to IMRT plans improving major comfort to the patient and reducing uncertainties associated with patient movement during treatment. The treatment using VMAT minimizes the biological effects of radiation to critical structures near to the target volumes and produces excellent dose distributions. The dosimetry of ionizing radiation is essential for the radiological protection programs for quality assurance and licensing of equipment. For radiation oncology a quality assurance program is essentially to maintain the quality of patient care. As the VMAT is a new technique of radiation therapy it is important to optimize quality assurance mechanisms to ensure that tests are performed in order to preserve the patient and the equipment. This paper aims to determinate the dose distribution in the target volume (tumor to be treated) and the scattered dose distribution in the risk organs for VMAT technique comparing data given by the planning system and thermoluminescent (TL) response. (author)

  11. TL dosimetric properties BAM:EU

    International Nuclear Information System (INIS)

    Rao, Bellam N.; Murthy, K.V.R.; Subba Rao, B.; Saiprasad, A.S.

    2011-01-01

    In phosphor area today top priority is the replacement of the high performance but very expensive rare earth activated phosphors with cheaper materials. This essentially means replacing the rare earth ions with transition metal ions or post transition ions. Now a day's phosphors are used in various fields. After World War II, the advances in the optical spectroscopy of solids, especially those of transition metals ions help to evolve research on phosphor and solid state luminescence. In 1960 efficient rare earth activated phosphors were developed for use in color TV (Tb 3+ green, Eu 3+ red, and Dy 3+ yellow). In 1970 tricolor lamp was introduced blue emission from Ce 3+ + Tb 3+ pair was used in tricolor lamps. At present combination of halo phosphor and tri-band phosphor blend is used in many lamp as a compromise between performance, phosphor cost and the lamp making Cost. Thermo luminescence of 0.5 Gy X-ray irradiated BAM.Eu has been studied. The irradiated phosphor has been studied for its TL dosimetric properties one week after irradiation and after 100 weeks of storage. Interesting TL results are reported in the present paper. Heating rate used in the present experiment is 6.6 deg C/Sec. The following two figures are on TL recorded 100 weeks after irradiation and TL recorded after 235 weeks of storage. Before storage for 100 weeks the TL glow curve with a hump around 180 deg C followed by a peak at 273 deg C. After storage for 100 weeks the TL pattern changes entirely. i.e. the composite TL peak structure emerged as two well resolved peaks and with slightly higher TL peak temperatures at 215 deg C and 300 deg C. Normally after storage for 100 weeks the peak at 190 deg C reduces in its intensity or disappears in some cases, instead of that the peak appears at 215 deg C as well resolved peak and its intensity is almost comparable to that of 300 deg C peak. Since the TL phenomenon observed is interesting the two well resolved, isolated, high intensity peaks

  12. Development and physical characteristics of a novel compound radiophotoluminescent glass dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, S.-M. [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, 155, Li-Nong Street Sec. 2, Pei-tou, Taipei 112, Taiwan (China)], E-mail: d49220003@ym.edu.tw; Yang, H.-W. [Department of Material Science and Engineering, National United University, No. 1, Lien Da, Miao-Li 360, Taiwan (China); Huang, David Y.C. [Facutly of Memorial Sloan-Kettering Cancer Center at Mercy Medical Center, 1000 N, Village Avenue, Rockville Centre, NY (United States); Hsu, W.-L.; Lu, C.-C. [Department of Material Science and Engineering, National United University, No. 1, Lien Da, Miao-Li 360, Taiwan (China); Chen, W.-L. [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, 155, Li-Nong Street Sec. 2, Pei-tou, Taipei 112, Taiwan (China)

    2008-02-15

    The thermoluminescent dosimeters (TLDs) are widely used for measuring the radiation dose. However, the luminescence centers of TLD disappeared by reading process, and then repetition of measurement is impossible. Radiophotoluminescent glass dosimeters (RPLGDs) can be repeatedly read and keep the luminescence centers for a long time. When machine errors occurred, RPLGD data can be re-analyzed to ensure the reliability of measurement results. Our previous study revealed that the RPLGD is one of the most important radiation dose measurement instruments as compared with TLD. Nevertheless, this RPLGD cannot measure the neutron dose. The aims of this study are to develop the novel compound of RPLGD to detect neutrons, and investigate their physical characteristics. In this study, some series self-fabricated glass dosimeters were prepared from reagent powders of AgCl, AgNO{sub 3}, AgPO{sub 3}, Al(OH){sub 3}, NaPO{sub 3}, Na{sub 2}CO{sub 3}, Na{sub 3}PO{sub 4} and P{sub 2}O{sub 5}. Based on this study, we found that the absorption spectra of irradiated glass wavelength maxima typically occurred in the 300-350 nm. Moreover, 0.1 mol% of sliver consist in our newly developed RPLGD showed the highest gamma ray detection sensitivity. The development of a novel compound RPLGD progress will be continuously improved in our laboratory.

  13. Radiation cytogenetic in vitro studies on human donors in the development of a suitable biological dosimeter

    International Nuclear Information System (INIS)

    Barjaktarovic, N.

    1988-02-01

    The final report is on the work carried out under the Agency research contract 3173/RB entitled ''Radiation cytogenetic in vitro studies on human donors in the development of a suitable biological dosimeter'', at the Clinical Hospital Centre ''Zvezdara'' in Belgrade, Yugoslavia. In co-operation and co-ordination dissemination with an international team of cytogeneticists under the IAEA CRP, the development of a suitable biological dosimetry system has been accomplished at the national institute to assist reliably in the absorbed radiation-dose assessment of accidentally-over-exposed personnel. The quantitative yield of asymmetrical chromosomal aberrations, such as dicentrics, rings and fragments consequent to exposure(s) to radiation overdose, help in such estimation of vital prognostic and radiation protection significance. This biological dosimeter system is particularly essential where the exposed person was not wearing any physical dosemeter during the accident. Prerequisite for implementation of an effective biological dosimetry is the availability of a reliable standard dose-response curve and an adherence to a protocol for lymphocytic chromosome analysis in first division phase of lymphocytes. The validation of the reported biological dosimeter is established through its successful analysis of a simulated over-exposure incident, with the associated error of less than 10%. Analytical cytogenetic methods for whole- and part-body acute exposures have been discussed. Part of the results have been reported in the publications under the CRP concerned

  14. Radiation dosimeter

    International Nuclear Information System (INIS)

    Lowe, D.

    1980-01-01

    A radiation dosimeter is described, comprising a thermoluminescent phosphor incorporated in matrix of polyethersulphone. The dosimeter is preferably a thin film formed by spreading a suspension of a powdered phosphor in a solution of polyethersulphone onto a flat surface. The solvent for the polyethersulphone is a mixture of a n-methyl-2-pyrrolidone and xylene in equal proportions. A thin, inert film of polyethersulphone can be cemented to one surface of the dosimeter so as to provide a skin dosimeter. (author)

  15. Plastic dosimeter

    International Nuclear Information System (INIS)

    Nagai, Shiro; Matsuda, Kohji.

    1988-01-01

    The report outlines major features and applications of plastic dosimeters. Some plastic dosimeters, including the CTA and PVC types, detect the response of the plastic material itself to radiations while others, such as pigment-added plastic dosimeters, contain additives as radiation detecting material. Most of these dosimeters make use of color centers produced in the dosimeter by radiations. The PMMA dosimeter is widely used in the field of radiation sterilization of food, feed and medical apparatus. The blue cellophane dosimeter is easy to handle if calibrated appropriately. The rad-color dosimeter serves to determine whether products have been irradiated appropriately. The CTA dosimeter has better damp proofing properties than the blue cellophane type. The pigment-added plastic dosimeter consists of a resin such as nylon, CTA or PVC that contains a dye. Some other plastic dosimeters are also described briefly. Though having many advantages, these plastic dosimeter have disadvantages as well. Some of their major disadvantages, including fading as well as large dependence on dose, temperature, humidity and anviroment, are discussed. (Nogami, K.)

  16. Development of a highly sensitive lithium fluoride thermoluminescence dosimeter

    International Nuclear Information System (INIS)

    Moraes da Silva, Teresinha de; Campos, Leticia Lucente

    1995-01-01

    In recent times, LiF: Mg, Cu, P thermoluminescent phosphor has been increasingly in use for radiation monitoring due its high sensitivity and ease of preparation. The Dosimetric Materials Production Laboratory of IPEN, (Nuclear Energy Institute) has developed a simple method to obtain high sensitivity LiF. The preparation method is described. (author). 4 refs., 1 fig., 1 tab

  17. Development of a semiconductor neutron dosimeter with a PIN diode

    International Nuclear Information System (INIS)

    Kim, Seungho; Lee, Namho; Cho, Jaiwan; Youk, Geunuck

    2004-01-01

    When a Si PIN diode is exposed to fast neutrons, it produces displacement in Si lattice structure of the diode. Defects induced from structural dislocation become effective recombination centers for carriers which pass through the base of a PIN diode. Hence, increasing the resistivity of the diode decreases the current for the applied forward voltage. This paper involves the development of a neutron sensor based on the phenomena of the displacement effect damaged by neutron exposure. The neutron effect on the semiconductor was analyzed, and multi PIN diode arrays with various intrinsic layer (I layer) thicknesses and cross sections were fabricated. Under irradiation tests with a neutron beam, the manufactured diodes have good characteristics of linearity in a neutron irradiation experiment and give results that the increase of thickness of I layer and the decrease of the cross-section of the PIN diodes improve the sensitivity. Newly developed PIN diodes with a thicker I layer and various cross sections were retested and showed the best neutron sensitivity in the condition that the I layer thickness was similar to the length of a side of the cross-section. On the basis of two test results, final PIN diodes with a rectangular shape were manufactured and the characteristics for neutron detectors were analyzed through the neutron beam test using the on-line electronic dosimetry system. The developed PIN diode shows a good linearity to absorbed dose in the range of 0 to 1,000cGy (Tissue) and its neutron sensitivity is 13 mV/cGy at a constant current of 5 mA, that is three higher than that of similar commercially developed neutron detectors. Moreover the device shows less dependency on the orientation of the neutron beam and a considerable stability in an annealing test for a long period. (author)

  18. SDI-100 radiation dosimeter

    International Nuclear Information System (INIS)

    Zheng Zheng; Zhao Yongfu; Dai Honggui

    1995-01-01

    An intelligent radiation dosimeter, with such functions as signal collection and data processing, store, print and display, has been developed. Its detector is made of a micro-semiconductor. This dosimeter can be used in laboratories for agricultural 60 Co irradiators, radiotherapeutic facilities and other small and medium-size 60 Co irradiators

  19. The development of new generation electronic personal dosimeters

    International Nuclear Information System (INIS)

    Aoyama, Kei; Nagase, Yoshiyuki; Suzuki, T.; Watanabe, Shinichi; Taniguchi, Kazufumi; Muramatsu, Kunihiro; Fujita, Mikio; Fujii, Yutaka

    2000-01-01

    We have developed two types of new small, light, electronic personal dosemeters (EPDs) which can be used for dose management of workers at nuclear power plants without additional dosemeters. The one is a card size dosemeter to measure gamma exposure dose and the other is a multi sensor dosemeter to measure gamma, beta and neutron dose respectively. With direct reading, alarm and instant readout, these EPDs have ruggedness and if failure happens, memory readout facility can read dose data in the dosemeter. These dosemeters have enough performance characteristics and reliability for use as a dose record dosemeter. The gamma dosemeter has a lightweight credit card size body to reduce workers' burden of wearing it. The multi sensor dosemeter has four hetero junction silicon detectors that detect gamma, beta, thermal and fast neutron respectively and it is smaller and lighter than conventional alarm dosemeters presently used at nuclear power plant. Thermal neutron detector has thin Boron layer deposited on silicon surface and fast neutron detector has polyethylene radiator in front of silicon wafer. These dosemeters with a rechargeable battery can operate more than 15 hours continuously. The data transmission can be made with radiofrequency wave in area smaller than 30 cm distance between dosemeter and readout system. These dosemeters were introduced into Tokai nuclear power plant on October 1997, Tsuruga nuclear power plant on December 1997 of Japan Atomic Power Company and have been operating satisfactorily. At now these EPD have been used as secondary dosemeters. The performance characteristics comparison between EPD and film badge(FB) have been continuing to assure EPD suitable for use as a primary dosemeter. Near future Japco will abolish FB and establish the radiation control system based on the electronic personal dosemeters as a dose record dosemeter. (author)

  20. Passive radon daughter dosimeters

    International Nuclear Information System (INIS)

    McElroy, R.G.C.; Johnson, J.R.

    1986-03-01

    On the basis of an extensive review of the recent literature concerning passive radon daughter dosimeters, we have reached the following conclusions: 1) Passive dosimeters for measuring radon are available and reliable. 2) There does not presently exist an acceptable passive dosimeter for radon daughters. There is little if any hope for the development of such a device in the foreseeable future. 3) We are pessimistic about the potential of 'semi-passive dosimeters' but are less firm about stating categorically that these devices cannot be developed into a useful radon daughter dosimeter. This report documents and justifies these conclusions. It does not address the question of the worker's acceptance of these devices because at the present time, no device is sufficiently advanced for this question to be meaningful. 118 refs

  1. Fundamentals of Polymer Gel Dosimeters

    Science.gov (United States)

    McAuley, Kim B.

    2006-12-01

    The recent literature on polymer gel dosimetry contains application papers and basic experimental studies involving polymethacrylic-acid-based and polyacrylamide-based gel dosimeters. The basic studies assess the relative merits of these two most commonly used dosimeters, and explore the effects of tetrakis hydroxymethyl phosphonium chloride (THPC) antioxidant on dosimeter performance. Polymer gel dosimeters that contain THPC or other oxygen scavengers are called normoxic dosimeters, because they can be prepared under normal atmospheric conditions, rather than in a glove box that excludes oxygen. In this review, an effort is made to explain some of the underlying chemical phenomena that affect dosimeter performance using THPC, and that lead to differences in behaviour between dosimeters made using the two types of monomer systems. Progress on the development of new more effective and less toxic dosimeters is also reported.

  2. Fast-neutron solid-state dosimeter

    International Nuclear Information System (INIS)

    Kecker, K.H.; Haywood, F.F.; Perdue, P.T.; Thorngate, J.H.

    1975-01-01

    This patent relates to an improved fast-neutron solid-state dosimeter that does not require separation of materials before it can be read out, that utilizes materials that do not melt or otherwise degrade at about 300 0 C readout temperature, that provides a more efficient dosimeter, and that can be reused. The dosimeters are fabricated by intimately mixing a TL material, such as CaSO 4 :Dy, with a powdered polyphenyl, such as p-sexiphenyl, and hot-pressing the mixture to form pellets, followed by out-gassing in a vacuum furnace at 150 0 C prior to first use dosimeters

  3. Pen dosimeters

    CERN Multimedia

    SC/RP Group

    2006-01-01

    The Radiation Protection Group has decided to withdraw all pen dosimeters from the main PS and SPS access points. This will be effective as of January 2006. The following changes will be implemented: All persons working in a limited-stay controlled radiation area must wear an operational dosimeter in addition to their personal DIS dosimeter. Any persons not equipped with this additional dosimeter must contact the SC/RP Group, which will make this type of dosimeter available for temporary loan. A notice giving the phone numbers of the SC/RP Group members to contact will be displayed at the former distribution points for the pen dosimeters. Thank you for your cooperation. The SC/RP Group

  4. Alarm pocket dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Hiraki, H; Kitamura, S [Matsushita Electric Industrial Co. Ltd., Kadoma, Osaka (Japan)

    1975-04-01

    This instrument is a highly reliable pocket dosimeter which has been developed for personal monitoring use. The dosimeter generates an alarm sound when the exposure dose reaches a preset value. Using a tiny GM tube for a radiation detector and measuring the integrated dose by means of a digital counting method, this new pocket dosimeter has high accuracy and stability. Using a sealed alkali storage battery for the power supply, and with an automatic control charger, this dosimetry system is easy and economical to operate and maintain. Detectable radiation by the dosimeter are X and ..gamma.. rays. Standard preset dose values are 30, 50, 80 and 100 mR. Detection accuracy is betwen +10% and -20%. The dosimeter is continuously usable for more than 14 hours after charging for 2 hours. The dosimeter has the following features; good realiability, shock-proof loud and clear alarm sound, the battery charger also serves as a stock container for the dosimeters, and no switching operation required for the power supply due to the internal automatic switch. Therefore, the dosimetry system is very useful for personal monitoring management in many radiation industry establishments.

  5. Dosimetric characteristics of LKB:Cu,P solid TL detector

    International Nuclear Information System (INIS)

    Hashim, S.; Alajerami, Y.S.M.; Ghoshal, S.K.; Saleh, M.A.; Saripan, M.I.; Kadir, A.B.A.; Bradley, D.A.; Alzimami, K.

    2014-01-01

    The dosimetric characteristics of newly developed borate glass dosimeter modified with lithium and potassium carbonate (LKB) and co-doped with CuO and NH 4 H 2 PO 4 are reported. Broad peaks in the absence of any sharp peak confirms the amorphous nature of the prepared glass. A simple glow curve of Cu doped sample is observed with a single prominent peak (T m ) at 220 °C. The TL intensity response shows an enhancement of ∼100 times due to the addition of CuO (0.1 mol%) to LKB compound. A further enhancement of the intensity by a factor of 3 from the addition of 0.25 mol% NH 4 H 2 PO 4 as a co-dopant impurity is attributed to the creation of extra electron traps with consequent increase in energy transfer of radiation recombination centers. The TL yield performance of LKB:Cu,P with Z eff ≈8.92 is approximately seventeen times less sensitive compared to LiF:Mg,Ti (TLD-100). The proposed dosimeter shows good linearity up to 10 3 Gy, minimal fading and photon energy independence. These attractive features offered by our dosimeter is expected to pave the way towards dosimetric applications. - Highlights: • The NH 4 H 2 PO 4 impurities are cross linked with the CuO defect. • The addition of NH 4 H 2 PO 4 as a co-dopant improved the TL intensity by a factor of 3. • The proposed dosimeter shows good linearity up to 10 3 Gy. • Minimal fading and photon energy independence were observed

  6. Development of based on 89S51 single-chip microcomputer electronic dosimeter

    International Nuclear Information System (INIS)

    Wang Junhua; Zhou Jiachao; Sun Jianghan; Du Xiao

    2009-01-01

    It describes the main design features and basic properties of based on 89S51 single-chip microcomputer electronic dosimeter with wide range and multi purposes. The dosimeter can display dose rate or accumulative dose or the maximum dose rate, record accumulative dose, the maximum dose rate and classes. (authors)

  7. Development study of a quality control for clinical dosimeters of radiotherapy

    International Nuclear Information System (INIS)

    Damatto, Willian B.; Potiens, Maria P.A.; Santos, Gelson P.; Vivolo, Vitor

    2011-01-01

    This paper presents the partial results of a scientific initiation which the main objective is the enhancement of the quality system of the dosimeter calibration laboratory (LCI-IPEN) on 60 Co gamma radiation to the International Atomic Energy Agency (IAEA), being this the new protocol denominated Calibration of Reference Dosimeters for External Beam Radiotherapy (Technical Reports Series 469). This paper is an actualization of the protocol Absorbed Dose Determination for External Beam Radiotherapy (Technical Reports Series 398). Therefore, in this paper it will presented the study on the clinical dosimeters composed of electrometer, wires, triaxial connectors, and thimble type ionization chamber - 0.60 cm 3 . (author)

  8. Determination of kinetic parameters in Tl dosemeters of LiF: Mg, Cu, P + PTFE developed in the ININ

    International Nuclear Information System (INIS)

    Basurto G, B.S.

    2002-01-01

    The objective of this work, is the one of determining the kinetic parameters of the dosemeter of LiF: Mg, Cu, P + Ptfe; starting from the curves Tl obtained at being irradiated with alpha radiation (α), beta (β) and gamma (γ). As like to compare its sensitivity with each radiation type, considering the sensitivity of the TLD-100 as the unit. In the Chapter 1, the fundamental structure of the matter is described, making emphasis in the different radiation types, and their interaction with this. In the Chapter 2, the units are described but used in the dosimetry of the radiation. In the Chapter 3, the basic concepts of the phenomenon of Tl are described and those are explained characteristic of the deconvolution method to determine the kinetics of the one phenomenon. In the Chapter 4, the methodology is detailed that was used in the elaboration of this thesis work, describing the material Tl that were considered like reference, as well as the sources of ionizing radiation, with those that the dosemeters were irradiated and the equipment in the one that the curves Tl was obtained. Reference is made to the software used to carry out the deconvolution of the curves Tl that were obtained in the one experimental development. In the Chapter 5, the obtained results of this study are presented, showing the tables of homogenization of dosemeters and the reading of the same one; they are observed the curves Tl obtained to different radiation doses (alpha, beta and gamma), the intensity Tl in function of the dose. Also they are tabulated, the obtained results in the kinetic parameters of the three different study materials (TLD-100H, USA; TLD-100, USA and LiF: Mg, Cu, P + Ptfe developed in the l.N.l.N). They are analyzed shortly for each material Tl their sensitivity to the ionizing radiation as well as their kinetic parameters. The obtained results showed that the Tl dosemeters of LiF: Mg,Cu,P + Ptfe, they presented a bigger sensitivity that the TLD-100 when being

  9. Development of GM tube electronic personal dosimeter with wide range and multi-purposes

    International Nuclear Information System (INIS)

    Li Jing; Weng Puyu; Chen Mingjun; Hu Zunsu; Huang Chenguang; Lei Jindian

    2003-01-01

    This paper describes the main design features and basic properties of a GM tube electronic personal dosimeter with wide range and multi-purposes. the dosimeter can display dose-rate or accumulative dose or the maximum dose-rate, record accumulative dose and the maximum dose-rate as well as the time of its appearance and at most 160 historical dose values within 8 h. All recorded data can directly be sent to PC by the infrared communication

  10. Neutron dosimeter

    International Nuclear Information System (INIS)

    Bartko, J.; Schoch, K.F. Jr.; Congedo, T.V.; Anderson, S.L. Jr.

    1989-01-01

    This patent describes a nuclear reactor. It comprises a reactor core; a thermal shield surrounding the reactor core; a pressure vessel surrounding the thermal shield; a neutron dosimeter positioned outside of the thermal shield, the neutron dosimeter comprising a layer of fissile material and a second layer made of a material having an electrical conductivity which permanently varies as a function of its cumulative ion radiation dose; and means, outside the pressure vessel and electrically connected to the layer of second material, for measuring electrical conductivity of the layer of second material

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

    Science.gov (United States)

    Avarmaa, Kirsten A.

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

  12. TL transgenic mouse strains

    International Nuclear Information System (INIS)

    Obata, Y.; Matsudaira, Y.; Hasegawa, H.; Tamaki, H.; Takahashi, T.; Morita, A.; Kasai, K.

    1993-01-01

    As a result of abnormal development of the thymus of these mice, TCR αβ lineage of the T cell differentiation is disturbed and cells belonging to the TCR γδ CD4 - CD8 - double negative (DN) lineage become preponderant. The γδ DN cells migrate into peripheral lymphoid organs and constitute nearly 50% of peripheral T cells. Immune function of the transgenic mice is severely impaired, indicating that the γδ cells are incapable of participating in these reactions. Molecular and serological analyses of T-cell lymphomas reveal that they belong to the γδ lineage. Tg.Tla a -3-1 mice should be useful in defining the role of TL in normal and abnormal T cell differentiation as well as in the development of T-cell lymphomas, and further they should facilitate studies on the differentiation and function of γδ T cells. We isolated T3 b -TL gene from B6 mice and constructed a chimeric gene in which T3 b -TL is driven by the promoter of H-2K b . With the chimeric gene, two transgenic mouse strains, Tg. Con.3-1 and -2 have been derived in C3H background. Both strains express TL antigen in various tissues including skin. The skin graft of transgenic mice on C3H and (B6 X C3H)F 1 mice were rejected. In the mice which rejected the grafts, CD8 + TCRαβ cytotoxic T cells (CTL) against TL antigens were recognized. The recognition of TL by CTL did not require the antigen presentation by H-2 molecules. The results indicated that TL antigen in the skin becomes a transplantation antigen and behaves like a typical allogeneic MHC class I antigen. The facts that (B6 X C3H)F 1 mice rejected the skin expressing T3 b -TL antigen and induced CTL that killed TL + lymphomas of B6 origin revealed that TL antigen encoded by T3 b -TL is recognized as non-self in B6 mice. Experiments are now extended to analyze immune responses to TL antigen expressed on autochthonous T cell lymphomas. (J.P.N.)

  13. Scintillation counter based radiation dosimeter

    International Nuclear Information System (INIS)

    Shin, Jeong Hyun

    2009-02-01

    The average human exposure per year is about 240mrem which is come from Radon and human body and terrestrial and cosmic radiation and man-made source. Specially radiation exposure through air from environmental radiation sources is 80mrem/yr(= 0.01mR/hr) which come from Terrestrial and cosmic radiation. Radiation dose is defined as energy deposit/mass. There are two major methods to detect radiation. First method is the energy integration using Air equivalent material like GM counter wall material. Second method is the spectrum to dose conversion method using NaI(Tl), HPGe. These two methods are using generally to detect radiation. But these methods are expensive. So we need new radiation detection method. The research purpose is the development of economical environmental radiation dosimeter. This system consists of Plastic/Inorganic scintillator and Si photo-diode based detector and counting based circuitry. So count rate(cps) can be convert to air exposure rate(R/hr). There are three major advantages in this system. First advantages is no high voltage power supply like GM counter. Second advantage is simple electronics. Simple electronics system can be achieved by Air-equivalent scintillation detector with Al filter for the same detection efficiency vs E curve. From former two advantages, we can know the most important advantages of the this system. Third advantage is economical system. The price of typical GM counter is about $1000. But the price of our system is below $100 because of plastic scintillator and simple electronics. The role of scintillation material is emitting scintillation which is the flash of light produced in certain materials when they absorb ionizing radiation. Plastic scintillator is organic scintillator which is kind of hydrocarbons. The special point are cheap price, large size production(∼ton), moderate light output, fast light emission(ns). And the role of Al filter is equalizing counting efficiency of air and scintillator for

  14. Development of a multichannel dosimeter for radiotherapy; Desenvolvimento de um dosimetro multicanal para radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Menezes, Claudio Jose Mesquita

    2000-06-01

    In radiotherapy, verification of the patient dose is of great important for the success of the treatment. Uncertainties in the evaluation of this dose can produce serious complications such as the loss of the control of the disease and damage to normal tissue. Semiconductor detectors present advantages over other types of radiation detectors such as ionization chambers and thermoluminescent dosimeters including small dimensions, high sensitivity and fast response. In this work, a multichannel dosimetric system is linear with dose, for a 6 MV x-ray beam and also with a beam of cobalt-60 gamma rays. The coefficients of determination of the calibration curves were better then 0,9998 in all cases. The four sensors presented similar response with the dose for different field sizes. The variation of the response was smaller than 1%. In a related study, depth dose was measured, and the results showed a good agreement compared to theoretical values. The angular response of the detectors showed a variation of 7% for angles of 45 deg C. Using the Anderson Random phantom, dose at the isocenter was determined from measurements of the surface dose. From the results obtained it can be concluded that the dosimetric system developed is adequate for the evaluation of many parameters in radiation fields used in radiotherapy. This system can be used to measure the patient entrance dose under treatment conditions, and the equipment can be used in the radiotherapy quality assurance program. (author)

  15. Low-cost commercial glass beads as dosimeters in radiotherapy

    International Nuclear Information System (INIS)

    Jafari, S.M.; Bradley, D.A.; Gouldstone, C.A.; Sharpe, P.H.G.; Alalawi, A.; Jordan, T.J.; Clark, C.H.; Nisbet, A.; Spyrou, N.M.

    2014-01-01

    Recent developments in advanced radiotherapy techniques using small field photon beams, require small detectors to determine the delivered dose in steep dose gradient fields. Commercially available glass jewellery beads exhibit thermoluminescent properties and have the potential to be used as dosimeters in radiotherapy due to their small size ( 60 Co gamma rays over doses ranging from 1 to 2500 cGy. A thermoluminescence (TL) system and an electron paramagnetic resonance (EPR) system were employed for read out. Both the TL and EPR studies demonstrated a radiation-induced signal, the sensitivity of which varied with bead colour. White coloured beads proved to be the most sensitive for both systems. The smallest and therefore least sensitive bead sizes allowed measurement of doses of 1 cGy using the TL system while that for the EPR system was approximately 1000 cGy. The fading rate was found to be 10% 30 days after irradiation with both readout systems. The dose response is linear with measured dose over the dose range 1 to 2500 cGy, with an R 2 correlation coefficient of greater than 0.999. The batch-to-batch reproducibility of a set of dosimeters after a single irradiation was found to be 3% (1 SD). The reproducibility of individual dosimeters was found to be 1.7%. No measurable angular dependence was found (results agreed within 1%). Dose rate response was found to agree within 1% for dose rates of 100 to 600 cGy/min. These results demonstrate the potential use of glass beads as TL dosimeters over the dose range commonly applied in radiotherapy. - Highlights: • We examined the dosimetric properties of a low cost commercially produced glass seed beads. • Glass beads are available in small size of 1–3 mm, suitable for dosimetry of small radiation fields. • The results demonstrate a mean reproducibility of 0.23% (2 SD), batch homogeneity of within 5%. • Dose response was linear over wide dose range tested for 1 cGy to kGy. • Improved fading effect of 10

  16. Development of NaI(Tl) scintillating films for imaging soft x-rays

    International Nuclear Information System (INIS)

    Shepherd, J.A.

    1993-01-01

    Thin film NaI(Tl) scintillators, of areas of up to 130 cm 2 , have been fabricated and characterized for use on soft x-ray imaging photomultiplier tubes. Relevant parameters of photon-counting imaging detectors are defined and used to predict the performance of several materials, including CsI(Na), CsI(Tl), CaF 2 (Eu), Lu 2 (SiO 4 )O:Ce, and NaI(Tl), as thin film scintillators on fiber optic substrates. Also, x-ray imaging methodologies are compared. The NaI(Tl) films were vapor-deposited onto quartz and fiber optic substrates using a powder flash deposition technique. When compared to single crystal NaI(Tl), the films were found to have equally high light yield but lower energy resolution. Light yield optimization was studied in detail including the effects of substrate temperature, activator concentration in the evaporant, and boat temperature. Spatial resolution as well as parallax errors are discussed and measured for film thicknesses up to 61 μm. A technique is described that can substantially increase the light collection of high index films on fiber optic disks. The light collection was improved by 20% by coating the disk with potassium silicate before the NaI(Tl) deposition. Large area films, up to 130 cm 2 , had a spatial uniformity of response within ±1.5% for count rate and ±3.5% for light yield, and their spatial resolution exceeded 16.6 lp mm -1 when deposited onto fiber optic substrates. The 8-keV x-ray detection efficiency of the microchannel plate imaging photomultiplier tube coupled to a NaI(Tl) film scintillator is predicted to be 88%. Other uses for the films are also described

  17. Development of portable ESR spectrometer as a reader for alanine dosimeters

    International Nuclear Information System (INIS)

    Kojima, T.; Haruyama, Y.; Tachibana, H.; Tanaka, R.; Okamoto, J.

    1993-01-01

    A prototype portable electron spin resonance (ESR) spectrometer was designed and tested, and its feasibility as a reader of alanine dosimeters was studied from the two standpoints of reproducibility of readings and sensitivity sufficient for dosimetry in the absorbed dose range 1-100 kGy. It has two main components: a permanent magnet and resonator; and a unit box with a microwave and auto-frequency control (AFC) circuit, a sweep controller of magnetic field, display, etc. In the present preliminary study, reproducibility values are measured with the same ESR parameters and alanine-polystyrene (alanine-PS) dosimeter at a dose of 1 kGy: repeatedly measuring without removing dosimeter from the cavity; individual measurement with removing and inserting again into the cavity with readjustment of ESR parameters. Alanine/ESR dosimetry using this spectrometer has a measurable dose range from 1 to 100 kGy with relatively high precision within ± 3% (1σ) as a preliminary result. The portable ESR spectrometer may also be modified as an automatic, more precise, dedicated alanine dosimeter reader. (author)

  18. Chemical dosimeter

    International Nuclear Information System (INIS)

    Baker, W.B.; Clark, D.G.

    1979-01-01

    The dosimeter may be carried by individuals e.g. at the belt and serves to monitor for vinyl-chloride vapors in industrial plants and for toxic radon gas and toxic radon gas products in mines. It contains a pump, sucking an air flow through an orifice and a filter, as well as a sensor circuit for detecting low air flow rates and a battery testing circuit. (DG) 891 HP/DG 892 MKO [de

  19. Determination of kinetic parameters in Tl dosemeters of LiF: Mg, Cu, P + PTFE developed in the ININ; Determinacion de parametros cineticos en dosimetros Tl de LiF: Mg, Cu, P + PTFE desarrollados en el ININ

    Energy Technology Data Exchange (ETDEWEB)

    Basurto G, B.S

    2002-07-01

    The objective of this work, is the one of determining the kinetic parameters of the dosemeter of LiF: Mg, Cu, P + Ptfe; starting from the curves Tl obtained at being irradiated with alpha radiation ({alpha}), beta ({beta}) and gamma ({gamma}). As like to compare its sensitivity with each radiation type, considering the sensitivity of the TLD-100 as the unit. In the Chapter 1, the fundamental structure of the matter is described, making emphasis in the different radiation types, and their interaction with this. In the Chapter 2, the units are described but used in the dosimetry of the radiation. In the Chapter 3, the basic concepts of the phenomenon of Tl are described and those are explained characteristic of the deconvolution method to determine the kinetics of the one phenomenon. In the Chapter 4, the methodology is detailed that was used in the elaboration of this thesis work, describing the material Tl that were considered like reference, as well as the sources of ionizing radiation, with those that the dosemeters were irradiated and the equipment in the one that the curves Tl was obtained. Reference is made to the software used to carry out the deconvolution of the curves Tl that were obtained in the one experimental development. In the Chapter 5, the obtained results of this study are presented, showing the tables of homogenization of dosemeters and the reading of the same one; they are observed the curves Tl obtained to different radiation doses (alpha, beta and gamma), the intensity Tl in function of the dose. Also they are tabulated, the obtained results in the kinetic parameters of the three different study materials (TLD-100H, USA; TLD-100, USA and LiF: Mg, Cu, P + Ptfe developed in the l.N.l.N). They are analyzed shortly for each material Tl their sensitivity to the ionizing radiation as well as their kinetic parameters. The obtained results showed that the Tl dosemeters of LiF: Mg,Cu,P + Ptfe, they presented a bigger sensitivity that the TLD-100 when

  20. Composite material dosimeters

    Science.gov (United States)

    Miller, Steven D.

    1996-01-01

    The present invention is a composite material containing a mix of dosimeter material powder and a polymer powder wherein the polymer is transparent to the photon emission of the dosimeter material powder. By mixing dosimeter material powder with polymer powder, less dosimeter material is needed compared to a monolithic dosimeter material chip. Interrogation is done with excitation by visible light.

  1. A new radiochromic dosimeter film

    Science.gov (United States)

    Sidney, L. N.; Lynch, D. C.; Willet, P. S.

    By employing acid-sensitive leuco dyes in a chlorine-containing polymer matrix, a new radiochromic dosimeter film has been developed for gamma, electron beam, and ultraviolet radiation. These dosimeter films undergo a color change from colorless to royal blue, red fuchsia, or black, depending on dye selection, and have been characterized using a visible spectrophotometer over an absorbed dose range of 1 to 100 kGy. The primary features of the film are improved color stability before and after irradiation, whether stored in the dark or under artificial lights, and improved moisture resistance. The effects of absorbed dose, dose rate, and storage conditions on dosimeter performance are discussed. The dosimeter material may be produced as a free film or coated onto a transparent substrate and optionally backed with adhesive. Potential applications for these materials include gamma sterilization indicator films for food and medical products, electron beam dosimeters, and in-line radiation monitors for electron beam and ultraviolet processing.

  2. Immunity against mouse thymus-leukemia antigen (TL) protects against development of lymphomas induced by a chemical carcinogen, N-butyl-N-nitrosourea.

    Science.gov (United States)

    Tsujimura, Kunio; Obata, Yuichi; Matsudaira, Yasue; Ozeki, Satoshi; Taguchi, Osamu; Nishida, Keiko; Okanami, Yuko; Akatsuka, Yoshiki; Kuzushima, Kiyotaka; Takahashi, Toshitada

    2004-11-01

    Mouse thymus-leukemia antigens (TL) are aberrantly expressed on T lymphomas in C57BL/6 (B6) and C3H/He (C3H) mice, while they are not expressed on normal T lymphocytes in these strains. When N-butyl-N-nitrosourea (NBU), a chemical carcinogen, was administered orally to B6 and C3H strains, lymphoma development was slower than in T3(b)-TL gene-transduced counterpart strains expressing TL ubiquitously as self-antigens, suggesting that anti-TL immunity may play a protective role. In addition, the development of lymphomas was slightly slower in C3H than in B6, which seems to be in accordance with the results of skin graft experiments indicating that both cellular and humoral immunities against TL were stronger in C3H than B6 mice. The interesting finding that B lymphomas derived from a T3(b)-TL transgenic strain (C3H background) expressing a very high level of TL were rejected in C3H, but not in H-2K(b) transgenic mice (C3H background), raises the possibility that TL-specific effector T cell populations are eliminated and/or energized to a certain extent by interacting with H-2K(b) molecules.

  3. Development of direct reading dosimeters for the dose 0-3 mSv and 0-5 mSv ranges for personnel monitoring

    International Nuclear Information System (INIS)

    Gaikwad, P.V.; Shirkar, Y.B.; Patil, A.S.; Madgaonkar, P.P.; Kale, K.L.; Guhagarkar, H.V.; Gandhi, D.P.; Gupta, S.K.; Kothiyal, G.P.; Sahni, V.C.

    1998-01-01

    Direct reading dosimeters (DRDs) are widely used to measure cumulative dose received by personnel working at nuclear reactor sites or in other environment having x- and gamma rays. A DRD operates on the principle of gold leaf electroscope, and is a small, rugged, hermetically sealed, self reading type device easily carried by an individual in his pocket. The development of dosimeters suitable for the dose ranges 0-3 mSv and 0-5 mSv is reported

  4. Development of low-background CsI(Tl) crystals for WIMP search

    International Nuclear Information System (INIS)

    Lee, H.S.; Bhang, H.; Hahn, I.S.; Hwang, M.J.; Kim, H.J.; Kim, S.C.; Kim, S.K.; Kim, S.Y.; Kim, T.Y.; Kim, Y.D.; Kwak, J.W.; Kwon, Y.J.; Lee, J.; Lee, J.I.; Lee, M.J.; Li, J.; Myung, S.S.; Park, H.; Zhu, J.J.

    2007-01-01

    Search for weakly interacting massive particles (WIMPs) is being carried out at the underground laboratory, Yangyang, Korea. Characteristics and internal background of CsI(Tl) crystal have been investigated. In our extensive R and D, we reduced internal background in the CsI(Tl) crystal. With the latest, we have achieved 5.50+/-0.10cpd (counts/keV/kg/day) at 10-15keV low-energy region. Further reduction of internal background is foreseen with the CsI powder lately produced

  5. On the Mechanisms of Formation of Memory Channels and Development of Negative Differential Resistance in Solid Solutions of the TlInTe2-TlYbTe2 System

    Science.gov (United States)

    Akhmedova, A. M.

    2018-04-01

    The behavior of an electronic subsystem is investigated in the course of formation and development of a memory channel in solid solutions of the TlInTe2-TlYbTe2 system. An analysis of the current-voltage characteristics allows getting an insight into the reason for a sharp change in electrical conductance of the specimens under study during their transition from the high-resistance to high-conductance state and the reasons for the well known instability of threshold converters, which makes it possible to design devices with high threshold voltage stability.

  6. Raising Awareness of Research Ethics in SoTL: The Role of Educational Developers

    Science.gov (United States)

    Stockley, Denise; Balkwill, Laura-Lee

    2013-01-01

    Does the subject of research ethics take you by surprise? Does it make you somewhat uncomfortable? Does it seem to have nothing to do with your research or your practice? These are the attitudes we have encountered about research ethics among some SoTL researchers at workshops and conferences. In many cases, these researchers had conducted…

  7. Optical dosimeter

    International Nuclear Information System (INIS)

    Drukaroff, I.; Fishman, R.

    1984-01-01

    A reflecting optical dosimeter is a thin block of optical material having an input light pipe at one corner and an output light pipe at another corner, arranged so that the light path includes several reflections off the edges of the block to thereby greatly extend its length. In a preferred embodiment, one corner of the block is formed at an angle so that after the light is reflected several times between two opposite edges, it is then reflected several more times between the other two edges

  8. Development of an alanine dosimeter for gamma dosimetry in mixed environments

    International Nuclear Information System (INIS)

    Vehar, D.W.; Griffin, P.J.

    1992-01-01

    L-αa-Alanine, a nontoxic polycrystalline amino acid, has been investigated for use in high-precision, high-level absorbed-dose measurements in mixed neutron/photon environments such as research and test reactors. The technique is based on the use of electron paramagnetic resonance (EPR) spectroscopy to determine the extent of free radical production in a sample exposed to ionizing radiation, and has been successfully used for photon absorbed-dose measurements at levels exceeding 10 5 Gy with high measurement precision. Application of the technique to mixed environments requires knowledge of the energy-dependent response of the dosimeter for both photons and neutrons. Determination of the dosimeter response to photons is accomplished by irradiations in 60 Co and bremsstrahlung sources and by calculations of energy-dependent photon kerma. Neutron response is determined by calculations in conjunction with CaF 2 :Mn thermoluminescence dosimeters and by calculations of energy-dependent neutron kerma. Several neutron environments are used, including the ACRR and SPR-III reactors

  9. Development of an alanine dosimeter for gamma dosimetry in mixed environments -- Summary of research

    International Nuclear Information System (INIS)

    Vehar, D.W.; Griffin, P.J.

    1994-02-01

    L-α-alanine, a nontoxic polycrystalline amino acid, has been investigated for use in high-precision, high-level absorbed-dose measurements in mixed neutron/photon environments such as research and test reactors. The technique is based on the use of electron paramagnetic resonance spectroscopy to determine the extent of free radical production in a sample exposed to ionizing radiation, and has been successfully used for photon absorbed-dose measurements at levels exceeding 10 5 Gy with high measurement precision. Application of the technique to mixed environments requires knowledge of the energy-dependent response of the dosimeter for both photons and neutrons. Determination of the dosimeter response to photons is accomplished by irradiations in 60 Co and bremsstrahlung sources and by calculations of energy-dependent photon kerma. Neutron response is determined by irradiations in conjunction with CaF 2 :Mn thermoluminescence dosimeters and by calculations of energy-dependent neutron kerma. Several neutron environments are used, including those provided by the Annular Core Research Reactor and Sandia Pulsed Reactor

  10. Development of a synthetic single crystal diamond dosimeter for dose measurement of clinical proton beams

    Science.gov (United States)

    Moignier, Cyril; Tromson, Dominique; de Marzi, Ludovic; Marsolat, Fanny; García Hernández, Juan Carlos; Agelou, Mathieu; Pomorski, Michal; Woo, Romuald; Bourbotte, Jean-Michel; Moignau, Fabien; Lazaro, Delphine; Mazal, Alejandro

    2017-07-01

    The scope of this work was to develop a synthetic single crystal diamond dosimeter (SCDD-Pro) for accurate relative dose measurements of clinical proton beams in water. Monte Carlo simulations were carried out based on the MCNPX code in order to investigate and reduce the dose curve perturbation caused by the SCDD-Pro. In particular, various diamond thicknesses were simulated to evaluate the influence of the active volume thickness (e AV) as well as the influence of the addition of a front silver resin (250 µm in thickness in front of the diamond crystal) on depth-dose curves. The simulations indicated that the diamond crystal alone, with a small e AV of just 5 µm, already affects the dose at Bragg peak position (Bragg peak dose) by more than 2% with respect to the Bragg peak dose deposited in water. The optimal design that resulted from the Monte Carlo simulations consists of a diamond crystal of 1 mm in width and 150 µm in thickness with the front silver resin, enclosed by a water-equivalent packaging. This design leads to a deviation between the Bragg peak dose from the full detector modeling and the Bragg peak dose deposited in water of less than 1.2%. Based on those optimizations, an SCDD-Pro prototype was built and evaluated in broad passive scattering proton beams. The experimental evaluation led to probed SCDD-Pro repeatability, dose rate dependence and linearity, that were better than 0.2%, 0.4% (in the 1.0-5.5 Gy min-1 range) and 0.4% (for dose higher than 0.05 Gy), respectively. The depth-dose curves in the 90-160 MeV energy range, measured with the SCDD-Pro without applying any correction, were in good agreement with those measured using a commercial IBA PPC05 plane-parallel ionization chamber, differing by less than 1.6%. The experimental results confirmed that this SCDD-Pro is suitable for measurements with standard electrometers and that the depth-dose curve perturbation is negligible, with no energy dependence and no significant dose rate

  11. Portable dosimeter

    International Nuclear Information System (INIS)

    Buffa, A.; Caley, R.; Pfaff, K.

    1986-01-01

    A simple but very accurate portable dosimeter is described for indicating the intensity of ionizing radiation, comprising, as a unit: (a) a radiation-detection chamber having a pair of parallel, facing, electrically-conducting, radiation-permeable electrodes spaced from each other to define a volume for a gas which is ionized by the radiation when exposed thereto; (b) electric potential supply means connected across the electrodes for attracting the gas ions to the electrodes and transferring their charge to the electrodes; (c) detection circuit means connected across the electrodes and having at least one of high-frequency electromagnetic- and radiation-sensitive components for detecting the charge on the electrodes and indicating therefrom a representation of the intensity of the radiation; (d) radiation shield means surrounding the radiation-sensitive components of the detection circuit means for shielding the latter from the ionizing radiation; (e) electric shield means surrounding the sensitive components of the detection circuit means for shielding the latter from electromagnetic interference including any caused by the ionizing radiation; and (f) ion shield means potting the ion-sensitive components for shielding them from radiation-caused ambient ionization; whereby the entire dosimeter may be assembled as the unit and portably transported into various radiation sources

  12. Dose determination algorithms for a nearly tissue equivalent multi-element thermoluminescent dosimeter

    International Nuclear Information System (INIS)

    Moscovitch, M.; Chamberlain, J.; Velbeck, K.J.

    1988-01-01

    In a continuing effort to develop dosimetric systems that will enable reliable interpretation of dosimeter readings in terms of the absorbed dose or dose-equivalent, a new multi-element TL dosimeter assembly for Beta and Gamma dose monitoring has been designed. The radiation-sensitive volumes are four LiF-TLD elements, each covered by its own unique filter. For media-matching, care has been taken to employ nearly tissue equivalent filters of thicknesses of 1000 mg/cm 2 and 300 mg/cm 2 for deep dose and dose to the lens-of-the-eye measurements respectively. Only one metal filter (Cu) is employed to provide low energy photon discrimination. A Thin TL element (0.09 mm thick) is located behind an open window designed to improve the energy under-response to low energy beta rays and to provide closer estimate of the shallow dose equivalent. The deep and shallow dose equivalents are derived from the correlation of the response of the various TL elements to the above quantities through computations based on previously defined relationships obtained from experimental results. The theoretical formalization for the dose calculation algorithms is described in detail, and provides a useful methodology which can be applied to different tissue-equivalent dosimeter assemblies. Experimental data has been obtained by performing irradiation according to the specifications established by DOELAP, using 27 types of pure and mixed radiation fields including Cs-137 gamma rays, low energy photons down to 20 keV, Sr/Y-90, Uranium, and Tl-204 beta particles

  13. Development of label dosimeters and analytical methods to verify absorbed dose in irradiated dried fruits/tree nuts

    International Nuclear Information System (INIS)

    Sattar, Abdus; Ahmad, Anwar; Atta, Shaheen

    2001-01-01

    Density measurements of fresh/dried fruits and tree nuts varied depending upon the package size, type and the nature of the sample. For the development of label dosimeters, the samples of clear PMMA in the thickness range of 410 mm gave a linear response in relation to the irradiation doses (0.125-1.0 kGy) and the optical response was stable almost for 6 months at ambient storage (20-35 deg. C; R.H 40-80%). Flexible polymers (polyethylene and PVC) materials were not found suitable in the dose range of 0.1-3.0 kGy. Subjective evaluation of Sterin indicator, an ISP product from USA, revealed that this new material is generally reliable, however, they were also affected by the doses lower than their threshold values (125 and 300 Gy) as well as exposure to light during storage. The yellow PMMA dosimeter (YLPMMA) developed by China was useful in the range of 125-1000 Gy of gamma radiation. Dose distribution studies of research irradiator at NIFA and a commercial gamma source (PARAS) at Lahore, indicated almost a good dose uniformity in the product containers in each case. Among the analytical methods (thermoluminescence and gas chromatography) the thermoluminescence measurements exhibited clearly reproducible and dose dependent differences between treated (0.5-1.5 kGy) and untreated samples of dried fruits/nuts. (author)

  14. Performance testing of personnel extremity dosimeters by Korean LiF: Mg, Cu, Na, Si TLD(KLT-300)

    International Nuclear Information System (INIS)

    Kim, J.L.; Lee, J.I.; Chang, S.Y.; Choi, H.S.; Lee, D.H.; Han, S.J.

    2005-01-01

    Full text: As the needs and opportunities for utilization of atomic energy and radiation are increasing, the related industries, medicines, environments are developing and the relevant organizations and companies are also becoming diverse. In result, the types and kinds of the radiation related to occupational environments are becoming diversified. For the whole body dosimeters, the methodology and criteria for the performance evaluation and safety regulations and laws have been prepared in some detail, but for the extremity dosimeters, those are not prepared yet in Korea. The extremity dosimeters are required when the extremity part of our body, such as hand, elbow, and arm below the elbow, the foot, knee, and leg below the knee are exposed to the radiation in specific work environments. The dosimeter irradiation conditions are clearly discriminated between the whole body exposure condition and the extremity exposure condition. By the investigation and analysis of the management status and dose evaluation methods of the extremity dosimeters for the local absorbed dose, the personnel monitoring system of the extremity dosimeter services in Korea can be diagnosed, and the performance testing criteria and procedures can be established. Therefore, this study presents the performance testing results of extremity dosimeters on the finger and arm/leg phantoms by the procedures recommended in the ANSI (American National Standard) N13.32 using KLT-300 TL materials (LiF:Mg,Cu,Nas,Si) which were developed in Korea Atomic Energy Research Institute (KAERI). The results show that the performance index for the two types of phantoms are sufficiently satisfied with the prescribed tolerance level in the all of the test categories listed in the ANSI N13.32. These results and procedures used in this study can be applicable for regulatory body to establish the standard criteria for acceptable performance and testing conditions for personnel extremity dosimeters services in the

  15. Development of a gamma dosimeter using a photodiode; Desenvolvimento de um dosimetro para radiacao gama utilizando fotodiodo

    Energy Technology Data Exchange (ETDEWEB)

    Melo, F.A. de

    1988-05-01

    In the last years, the application of semiconductor detectors in radiation spectroscopy and dosimetry has increased. Silicon diodes have found utility in radiation dosimetry principally because a diode produces a current approximately 18000 times larger than of an ionization chamber of an equal sensitive volume. As the characteristics of the semiconductor detectors are the same as the common photodiode, a gamma dosimeter using this type of electronic component was developed. The photodiode SFH206 operating in photovoltaic mode was used. An electrometric unit was constructed to measure the current generated in this detector. The results obtained showed: the response of the photodiode was linear with the dose and that variation of 40 degrees in the incidence angle of the radiation caused a variation of 5% in the dose determination; the response reproducibility of the photodiode was studied, and the results showed that the variation coefficient is smaller than 0,02%; the small dimension of the silicon photodiode recommend its use as a gamma dosimeter for medical applications. (author). 19 refs, 32 figs, 1 tab.

  16. Development of a coincidence circuit with nanosecond resolving time for NaI(Tl) scintillator pulses

    International Nuclear Information System (INIS)

    Ripon, R.; Coussot, G.

    1969-01-01

    The principle and the details of a slow-fast type coincidence circuit for pulses delivered by Nal(Tl) scintillators are presented. Thanks to a voluntary limitation of the analysis band (150 keV to 1 MeV) an excellent stability is obtained with respect to thermal drifts. The resolving time which has been adopted, 4 ns with 100 per cent efficiency, is quite sufficient for the projected experiment but does not represent the optimum performance of which the circuit is capable [fr

  17. Intrinsic thermoluminescence of NaCl:Tl in UV dosimetry

    International Nuclear Information System (INIS)

    Barghare, S.P.; Joshi, R.V.; Joshi, T.R.; Kathuria, S.P.

    1982-01-01

    NaCl:Tl(T) phosphor is found to have high intrinsic thermoluminescence (TL) sensitivity to 253.7 nm UV-radiation. The dosimetric glow peak II grows sublinearly with increase in UV dose in the range 10 3 to 10 6 JM -2 . The other requirements of an efficient dosimeter material such as high storage stability, matching of the spectral response of detector tube and TL-emission from phosphor, reproducibility, desirable size and shape, easy availability in powder, pellet and crystal forms at cheaper rates, and repeated re-usability of the same phosphor without much difficulty, etc., are additional factors which strengthen the claim of NaCl:Tl(T) phosphor as UV dosimetric material. It is proposed that present NaCl:Tl(T) material is suitable TL-phosphor for UV dosimetry in the range 10 3 to 10 6 JM -2 . (author)

  18. Recent progress in the development of CsI(Tl) crystal-Si-photodiode spectrometric detection assemblies

    International Nuclear Information System (INIS)

    Semynozhenko, V.P.; Grinyov, B.V.; Nekrasov, V.V.; Borodenko, Yu.A.

    2005-01-01

    Highly sensitive spectrometric γ-detection assemblies are developed using a comprehensive approach (optimization of crystal growth conditions as well as of treatment and packing of scintillators, creation of low-noise charge-sensitive preamplifiers and shapers). The detection assemblies with CsI(Tl)≤100 cm 3 have a sensitivity of about 20 pulse/s(mcR/h), their energy resolution with respect to 137 Cs γ-line being ≤8.5%. The assemblies with lesser scintillator volumes (1-5 cm 3 ) provide a resolution lower than 6% with respect to 137 Cs and ≤40% with respect to 241 Am

  19. New Neutron Dosimeter

    CERN Multimedia

    2001-01-01

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

  20. Luminescence studies of rare earth doped dosimeters

    International Nuclear Information System (INIS)

    Karali, T.

    1999-10-01

    The main objective of this thesis has been to address the applications and fundamentals of thermoluminescence (TL) and to contribute to existing knowledge about TL mechanisms in materials which are applied as radiation dosimeters. This issue has been explored for a long time but the mechanisms lack completeness and certainty. TL, Radioluminescence (RL) and Radio-thermoluminescence (RLTL) measurements have been conducted on a high sensitivity TL spectrometer both at low (30-290 K) and high (25-400 deg. C) temperatures, and different heat treatments (furnace and laser) were conducted in order to study the possible impurity clustering which changes the TL spectra and efficiency of the dosimeters. Studies have been based on three different host structure, namely sulphate, borates and zircon. The spectra of calcium sulphate samples doped with Tm 3+ and Dy 3+ at different concentration were examined using TL, RL and RLTL. Similar procedures were applied to the borate samples. Modifications of the material by thermal treatments convert the state of dispersion of the rare earth ions between isolated, pair or defect clusters, which alter the dosimeter efficiency. In some cases, modified geometries are detectable by movement of the line emissions such as for quenched samples which are attributable to new microcrystal line phases. The study of co-doped samples showed unequivocal evidence of a glow peak displacement of the two dopants within a single sample. This result supports the new view that RE 3+ ions could form part of a complex defect acting as both charge trap and recombination centres. Pulsed laser heating with a UV laser changed the glow curve shape and lead to strong signals. The detailed mechanisms for this process are discussed. The RL and TL spectra of synthetic zircon crystals doped with different RE 3+ ions (Pr, Sm, Eu, Gd, Ho, Dy, Er, and Yb) and phosphorus are reported. Even though there is some intrinsic emission from the host lattice the major signals are

  1. Applicability of thermoluminescent dosimeters in X-ray organ dose determination and in the dosimetry of systemic and boron neutron capture radiotherapy

    International Nuclear Information System (INIS)

    Aschan, C.

    1999-01-01

    The main detectors used for clinical dosimetry are ionisation chambers and semiconductors. Thermoluminescent (TL) dosimeters are also of interest because of their following advantages: (i) wide useful dose range, (ii) small physical size, (iii) no need for high voltage or cables, i.e. stand alone character, and (iv) tissue equivalence (LiF) for most radiation types. TL detectors can particularly be used for the absorbed dose measurements performed with the aim to investigate cases where dose prediction is difficult and not as part of a routine verification procedure. In this thesis, the applicability of TL detectors was studied in different clinical applications. Particularly, the major phenomena (e.g. energy dependence, sensitivity to high LET radiation, reproducibility) affecting on the precision and accuracy of TL detectors in the dose estimations were considered in this work. In organ dose determinations of diagnostic X-ray examinations, the TL detectors were found to be accurate within 5% (1 S.D.). For in viva studies using internal irradiation source, i.e. for systemic radiation therapy, a method for determining the absorbed doses to organs was introduced. The TL method developed was found to be able to estimate the absorbed doses to those critical organs near the body surface within 50%. In the mixed neutron-gamma field of boron neutron capture therapy (BNCT), TL detectors were used for gamma dose and neutron fluence measurements. They were found able to measure the neutron dose component with the accuracy of 16%, and therefore to be a useful addition to the activation foils in BNCT neutron dosimetry. The absorbed gamma doses can be measured with TL detectors within 20% in the mixed neutron-gamma field, which enables in viva measurements at BNCT beams with approximately the same accuracy. In this study, the uncertainties of TL dosimeters were found to be high but not essentially greater than those in other measurement techniques used for clinical dosimetry

  2. Accidental and retrospective dosimetry using TL method

    International Nuclear Information System (INIS)

    Mesterházy, D.; Osvay, M.; Kovács, A.; Kelemen, A.

    2012-01-01

    Retrospective dosimetry is one of the most important tools of accidental dosimetry for dose estimation when dose measurement was not planned. In the affected area many objects can be applied as natural dosimeters. The paper discusses our recent investigations on various electronic components and common salt (NaCl) having useful thermoluminescence (TL) properties. Among materials investigated the electronic components of cell phones seem promising for retrospective dosimetry purposes, having high TL responses, proper glow curve peaks and the intensity of TL peaks vs. gamma dose received provided nearly linear response in the dose range of 10 mGy–1.5 Gy. - Highlights: ► Electronic components and common salt were investigated for accidental and retrospective dosimetry. ► SMD resistors seem promising for retrospective dosimetry purposes. ► Table salt can be used effectively for accidental dosimetry purposes, as well.

  3. Acoustic evaluation of polymer gel dosimeters

    International Nuclear Information System (INIS)

    Mather, M.L.; De Deene, Y.; Baldock, C.; Whittaker, A.K.

    2002-01-01

    Advances in radiotherapy treatment techniques such as intensity modulated radiotherapy are placing increasing demands on radiation dosimetry for verification of dose distributions in 3D. In response, polymer gel dosimeters that are capable of recording dose distributions in 3D are currently being developed. Recently, a new technique for evaluation of absorbed dose distributions in these dosimeters using ultrasound was introduced. The current work aims to demonstrate the potential of ultrasound as an evaluation technique for polymer gel dosimeters and to investigate the ultrasound properties of two different dosimeter formulations, PAG and MAGIC gels

  4. Characterization of a new dosimeter for the development of a position-sensitive detector of radioactive sources in industrial NDT equipment

    Science.gov (United States)

    Kim, K. T.; Kim, J. H.; Han, M. J.; Heo, Y. J.; Park, S. K.

    2018-02-01

    Imaging technology based on gamma-ray sources has been extensively used in non-destructive testing (NDT) to detect any possible internal defects in products without changing their shapes or functions. However, such technology has been subject to increasingly stricter regulations, and an international radiation-safety management system has been recently established. Consequently, radiation source location in NDT systems has become an essential process, given that it can prevent radiation accidents. In this study, we focused on developing a monitoring system that can detect, in real time, the position of a radioactive source in the source guide tube of a projector. We fabricated a lead iodide (PbI2) dosimeter based on the particle-in-binder method, which has a high production yield and facilitates thickness and shape adjustment. Using a gamma-ray source, we then tested the reproducibility, linearity of the dosimeter response, and the dosimeter's percentage interval distance (PID). It was found that the fabricated PbI2 dosimeter yields highly accurate, reproducible, and linear dose measurements. The PID analysis—conducted to investigate the possibility of developing a monitoring system based on the proposed dosimeter—indicated that the valid detection distance was approximately 11.3 cm. The results of this study are expected to contribute to the development of an easily usable radiation monitoring system capable of significantly reducing the risk of radiation accidents.

  5. Development of dosimeters with rad-hard silicon diodes for high dose dosimetry

    International Nuclear Information System (INIS)

    Camargo, Fabio de

    2009-01-01

    In this work we report on results obtained with rad-hard Standard Float Zone (FZ), Diffusion Oxygenated Float Zone (DOFZ) and Magnetic Czochralski (MCz) silicon diodes in gamma radiation processing dosimetry. These p ± n-n + junction devices were manufactured by Okmetic Oyj. (Vantaa, Finland) and processed by the Microelectronics Center of Helsinki University of Technology in the framework of the CERN RD50 Collaboration. The dosimetric probes, based on FZ, DOFZ and M Cz devices, were designed to operate without bias voltage in the direct current mode as on-line radiation dosimeter. The irradiations were performed in the Radiation Technology Center (CTR) at IPEN-CNEN/SP using a 60 Co source (Gamma cell 220 - Nordion) with a dose rate around of 2.4 kGy/h. The current response of each diode was measured as a function of the exposure time in steps from 5 kGy up to 50 kGy to achieve a total absorbed dose of 275 kGy. The results obtained showed a significant decrease in the photocurrent generated in all devices for total absorbed doses higher than approximately 25 kGy. To reduce this effect, the samples were pre-irradiated with 60 Co gamma rays at 700 kGy in order to saturate the trap production in the diode's sensitive volume. After pre-irradiation, despite of being less sensitive, all devices exhibited more stable photocurrent signals, even for total absorbed doses of 275 kGy. To monitor possible gamma radiation damage effects produced on the diodes, their dynamic leakage current and capacitance were measured as a function of the absorbed dose. (author)

  6. Development of a red TL detection system for a single grain of quartz

    International Nuclear Information System (INIS)

    Yawata, T.; Hashimoto, T.

    2007-01-01

    Red thermoluminescence (RTL) of natural quartz grains offers many desirable properties for quaternary chronology and archaeological dating, although RTL measurements suffer from high thermal background due to black-body radiation on heating. To reduce the thermal background to as low a level as possible, a silver sample disc covered with a biotite plate with a sample hole was used in combination with a light guide, cluster heater, optical filters, and photomultiplier tube cooling to -20 deg. C in the present system. As a result, the thermal background decreased from 2x10 4 to 1000 cps in the temperature range 350-380 deg. C, resulting in a detection limit of approximately 100 cps, corresponding to the RTL signal from a single quartz grain (250-500μm) irradiated with 4.0 Gy. In addition, application of lower heating rates retarded the thermal quenching effect, resulting in high RTL signals, which are preferable for young or insensitive quartz samples. Using RTL measurements with the single quartz grain method under optimal RTL conditions, comparison of equivalent doses from artificially irradiated single quartz grains to the known dose was within the 20% measurement error. Based on equivalent dose determinations for single quartz grains, large irregularities on non-etched quartz surfaces might be very detrimental to the TL detection process. This result confirms that surface etching treatment is required to achieve reliable dating with high counting efficiency

  7. 205Tl experiment

    International Nuclear Information System (INIS)

    Henning, W.; Kutschera, W.; Ernst, H.

    1984-01-01

    205 Tl has been previously proposed as a geological detector for solar neutrinos, making use of the reaction 205 Tl(nu, e - ) 205 Pb with a neutrino threshold of only approx. = 43 keV. We report on an experiment performed to study the feasibility of detecting radioactive 205 Pb nuclei (T/sub 1/2/ = 15 million years) at very low concentrations using the recently developed technique of accelerator mass spectrometry. Employing the high-energy ion beams of good quality from the UNILAC heavy-ion accelerator at the GSI Darmstadt, we are able to demonstrate a suppression of neighbouring isotopes to better than 1 in 10 16 and of neighbouring elements to about 1 in 10 3 . While these results are very encouraging, the minimum number of atoms detectable is still severely limited by the efficiency of producing multiply-charged ions from present ion sources. Future improvements in ion-source performance are briefly discussed

  8. The influence of thermal annealing on the characteristics of different AL2O3 thermoluminescence dosimeters

    International Nuclear Information System (INIS)

    Ranogajec-Komor, M.; Vincekovic, M.; Knezevic, Z.; Miljanic, S.

    2002-01-01

    The manufacturers of TL detectors usually recommend the annealing temperature and time, however they do not give instructions about the heating and cooling rates. From the aspect of practical routine work, every laboratory has to find the optimum heating and cooling method. In this work the influence of various parameters of annealing on the properties of TL dosimeters (sensitivity, reproducibility, the shape of the glow curve) was investigated. Various Al 2 O 3 :dosimeters were used. The TL dosimeters based on Al 2 O 3 can be used in different dose ranges depending on the crystal structure of the dosimeter material as well as the kind and concentration of the activator. In this work Al 2 O 3 :C 4 and Al 2 O 3 :Mg,Y with 0.5% and 1% of activator were investigated

  9. Performances of Dose Measurement of Commercial Electronic Dosimeters using Geiger Muller Tube and PIN Diode

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Hyunjun; Kim, Chankyu; Kim, Yewon; Kim, Giyoon; Cho, Gyuseong [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    There are two categories in personal dosimeters, one is passive type dosimeter such as TLD (thermoluminescence dosimeter) and the other is active type dosimeter such as electronic dosimeter can show radiation dose immediately while TLD needs long time to readout its data by heating process. For improving the reliability of measuring dose for any energy of radiations, electronic dosimeter uses energy filter by metal packaging its detector using aluminum or copper, but measured dose of electronic dosimeter with energy filter cannot be completely compensated in wide radiation energy region. So, in this paper, we confirmed the accuracy of dose measurement of two types of commercial EPDs using Geiger Muller tube and PIN diode with CsI(Tl) scintillator in three different energy of radiation field. The experiment results for Cs-137 was almost similar with calculation value in the results of both electronic dosimeters, but, the other experiment values with Na-22 and Co-60 had higher error comparing with Cs-137. These results were caused by optimization of their energy filters. The optimization was depending on its thickness of energy filter. So, the electronic dosimeters have to optimizing the energy filter for increasing the accuracy of dose measurement or the electronic dosimeter using PIN diode with CsI(Tl) scintillator uses the multi-channel discriminator for using its energy information.

  10. Evaluation of optical fibres as gamma radiation dosimeter

    International Nuclear Information System (INIS)

    Bohra, Dinesh; Chaudhary, H.S.; Panwar, Lalit; Vaijapurkar, S.G.; Bhatnagar, P.K.; Dasgupta, K.

    2005-01-01

    Semiconductor base gamma and neutron sensors are the fastest and popular dosimeters and are in competition with Thermoluminescence (TL) and Radio photoluminescence (RPL) dosimeters. All over the world armed forces require a dosimeter which records cumulative doses of ionizing radiations from mcGy to 10 Gy and is readable repeatedly without loss of dose information. TL dosimeters do not meet the criteria and RPL dosimeter meet the expectations and are in use by armed forces. Technologists have used laser as an excitation source to stimulate the glass and have achieved success in recording gamma doses of occupational/accidental span (mcGy to 10 Gy). However synthesizing RPL glass batches with exactly same characteristics predoses is a difficult task. Silicon base phosphorous doped step index multimode optical fibre can be made in a significant quantity and large number of dosimeters from it can be achieved with uniform predose. The radiation induced transmission loss gives a measure of gamma dose which is cumulative, readable repeatedly without loss of information. Assorted composition, core dia optical fibres have been synthesized and evaluated for dose linearity, dose rate independence, fading, length optimization. Here in is described some results of recent experiments and sensitivities achieved. (author)

  11. Passive dosimeters other than film and TLDs [thermoluminescent dosimeter

    International Nuclear Information System (INIS)

    Hankins, D.E.

    1986-01-01

    This presentation will describe CR-39 plastic as a personnel neutron dosimeter. Recent research at LLNL and elsewhere has resulted in the development of a dosimetry system that is superior to any personnel neutron dosimeter previously available. The author describes the features of the dosimetry system and the new etching procedures and techniques in detail. Most of the research was done at the LLNL and has been supported as a part of the DOE Neutron Dosimetry Upgrade Program. 10 refs., 4 figs., 1 tab

  12. Neutron dosimeter utilizing CR-39

    International Nuclear Information System (INIS)

    Souza, H.V.C. de.

    1991-05-01

    A personnel neutron dosimeter has been developed with discretization in a wide range of energies of real interest, utilizing the CR-39 polymer, to detect recoil protons in the fast range, and alpha particles in the thermal and epithermal ranges, with possibility to be disposed in the IRD/CNEN's conventional film badge suport. They are presented, abstractly, the difficulties and importance of the neutron dosimetry, beyond the general objectives that motivated this work execution. The details of the materials utilized in the dosimeter confection, and the experimental methodology employed to obtain the performance curves are presented. The results about linearity response of the dosimeter with respect to equivalent dose, in a wide range of doses, and about the verified angular dependence are analysed. (author)

  13. Indoor radon level measurements in Iran using AEOI passive dosimeters

    International Nuclear Information System (INIS)

    Sohrabi, M.; Solaymanian, A.R.

    1988-01-01

    A passive radon diffusion dosimeter was developed at the RPD of AEOI for nationwide indoor radon level measurements. Several parameters of the dosimeter were studied. Radon levels were determined in about 250 houses in Ramsar (a high natural radiation area), Tehran, Babolsar and Gonabad. In this paper, the results of some dosimeter parameters as well as radon levels in indoor air are reported

  14. Calibration and testing of the DMG gamma dosimeter

    International Nuclear Information System (INIS)

    Dolgirev, E.I.

    1987-01-01

    25-1000 nGy/h (2.5-1000 μrad/h) absorbed dose gamma dosimeter for measuring the efficient equivalent irradiation dose for population is developed. It has two subranges 1000 nGy/h and 250 nGy/h. Results of dosimeter calibration and testing are presented. The dosimeter error for both subranges is less than 10%

  15. Dosimeter charging apparatus

    International Nuclear Information System (INIS)

    Reuter, F.A.; Moorman, Ch.J.

    1985-01-01

    An apparatus for charging a dosimeter which has a capacitor connected between first and second electrodes and a movable electrode in a chamber electrically connected to the first electrode. The movable electrode deflects varying amounts depending upon the charge present on said capacitor. The charger apparatus includes first and second charger electrodes couplable to the first and second dosimeter electrodes. To charge the dosimeter, it is urged downwardly into a charging socket on the charger apparatus. The second dosimeter electrode, which is the dosimeter housing, is electrically coupled to the second charger electrode through a conductive ring which is urged upwardly by a spring. As the dosimeter is urged into the socket, the ring moves downwardly, in contact with the second charger electrode. As the dosimeter is further urged downwardly, the first dosimeter electrode and first charger electrode contact one another, and an insulator post carrying the first and second charger electrodes is urged downwardly. Downward movement of the post effects the application of a charging potential between the first and second charger electrodes. After the charging potential has been applied, the dosimeter is moved further into the charging socket against the force of a relatively heavy biasing spring until the dosimeter reaches a mechanical stop in the charging socket

  16. Doped Tl-1212 and Tl-1223 superconductors

    International Nuclear Information System (INIS)

    Eder, M.H.

    2001-09-01

    This work describes the preparation and characterization of thallium-lead-strontium-barium-calcium-(uranium)-copperoxide (Tl-1212, Tl-1223) high-temperature superconductors. The precursors were prepared via nitrate method. After calcination the oxidic powders were mixed with stoichiometric amounts of an Tl 2 O 3 , PbO, Er 2 O 3 and Gd 2 O 3 by milling and afterwards uniaxial compressed. Sintering was carried out in silver foils. X-ray diffractometry and high-resolution microscopy in combination with scanning electron microscopy (including EDAX) were used to study the influence of varying thallium/lead-, strontium/barium-, calcium/rare earth element ratios and the effect of uranium on the phase composition and microstructure of bulk superconductors. Furthermore the influence of the composition on the electrical and magnetical properties was studied. On phase pure Tl-1212 and Tl-1223 superconductors NMR-measurements were done. Small amounts of gadolinium and erbium instead of calcium and excess-uranium have a positive impact on the electrical and magnetical properties of the Tl-1223 superconductors. Higher amounts of these doping elements favor the Tl-1212 phase. Tl-1212 superconductors with varying thallium/lead- strontium/barium- and calcium/gadolinium ratios were prepared phasepure in wide range of doping. Transition temperatures up to 96 K were achieved. It was shown that lead has an oxidation number of +4 and thallium of +3. (author)

  17. Application of the thermoluminescent (TL) and optically stimulated luminescence (OSL) dosimetry techniques to determinate the isodose curves in a cancer treatment planning simulation using Volumetric Modulated Arc Therapy - VMAT

    International Nuclear Information System (INIS)

    Bravim, Amanda

    2015-01-01

    The Volumetric Modulated Arc Therapy (VMAT) is an advance technique of Intensity Modulated Radiation Therapy (IMRT). This progress is due to the continuous gantry rotation with the radiation beam modulation providing lower time of the patient treatment. This research aimed the verification of the isodose curves in a simulation of a vertebra treatment with spinal cord protection using the thermoluminescent (TL) and optically stimulated luminescence (OSL) dosimetry techniques and the LiF:Mg,Ti (TLD-100), CaS0 4 :Dy and Al 2 0 3 :C dosimeters and LiF:Mg,Ti micro dosimeters (TLD-100). The dosimeters were characterized using PMMA plates of 30 x 30 x 30 cm 3 and different thickness. All irradiations were done using Truebeam STx linear accelerator of Hospital Israelita Albert Einstein, with 6 MV photons beam. After the dosimeter characterization, they were irradiated according the specific planning simulation and using a PMMA phantom developed to VMAT measurements. This irradiation aimed to verify the isodose curves of the treatment simulation using the two dosimetry techniques. All types of dosimeters showed satisfactory results to determine the dose distribution but analysing the complexity of the isodose curves and the proximity of them, the LiF:Mg,Ti micro dosimeter showed the most appropriate for use due to its small dimensions. Regarding the best technique, as both technique showed satisfactory results, the TL technique presents less complex to be used because the most of the radiotherapy departments already have a TL laboratory. The OSL technique requires more care and greater investment in the hospital. (author)

  18. OSL and TL retrospective dosimetry with a fluorapatite glass-ceramic used for dental restorations

    International Nuclear Information System (INIS)

    Ekendahl, Daniela; Judas, Libor; Sukupova, Lucie

    2013-01-01

    Optically Stimulated Luminescence (OSL) and Thermoluminescence (TL) properties of a fluorapatite glass-ceramic have been investigated, with a view to developing a dose assessment technique for medical triage following unplanned exposures of individuals to ionizing radiation. The ceramic is an innovative material used in dental prostheses and restorations. It is strongly sensitive to radiation and the intensity of both the OSL and TL signals are proportional to the absorbed radiation dose. We focused on the optimization of the measuring procedure and investigated characteristics such as reproducibility, fading, minimum detectable dose (MDD), dose response and photon energy response of TL and OSL signals. The dental ceramic exhibited very good reproducibility (<5% at 2σ level) when measured and a linear dose response for a wide range of doses (50 mGy–20 Gy). The MDD values for the samples investigated were ∼5 mGy. The material is not tissue equivalent and the OSL and TL signals are strongly dependent on incident photon energy. Both the luminescence signals exhibited significant fading during the first few hours after irradiation. Its rate was dependent on the parameters of measurement. The results indicate that the material can be used for the purposes of accident dosimetry, however, the fading and photon energy response have to be properly corrected for a reliable dose assessment. - Highlights: ► A dental ceramic was considered as a retrospective and accident dosimeter. ► Dosimetry application was investigated using OSL and TL. ► TL and OSL signals are proportional to absorbed radiation dose. ► Accuracy is dependent on correction of fading and photon energy response

  19. Development of Solid Ceramic Dosimeters for the Time-Integrative Passive Sampling of Volatile Organic Compounds in Waters.

    Science.gov (United States)

    Bonifacio, Riza Gabriela; Nam, Go-Un; Eom, In-Yong; Hong, Yong-Seok

    2017-11-07

    Time-integrative passive sampling of volatile organic compounds (VOCs) in water can now be accomplished using a solid ceramic dosimeter. A nonporous ceramic, which excludes the permeation of water, allowing only gas-phase diffusion of VOCs into the resin inside the dosimeter, effectively captured the VOCs. The mass accumulation of 11 VOCs linearly increased with time over a wide range of aqueous-phase concentrations (16.9 to 1100 μg L -1 ), and the linearity was dependent upon the Henry's constant (H). The average diffusivity of the VOCs in the solid ceramic was 1.46 × 10 -10 m 2 s -1 at 25 °C, which was 4 orders of magnitude lower than that in air (8.09 × 10 -6 m 2 s -1 ). This value was 60% greater than that in the water-permeable porous ceramic (0.92 × 10 -10 m 2 s -1 ), suggesting that its mass accumulation could be more effective than that of porous ceramic dosimeters. The mass accumulation of the VOCs in the solid ceramic dosimeter increased in the presence of salt (≥0.1 M) and with increasing temperature (4 to 40 °C) but varied only slightly with dissolved organic matter concentration. The solid ceramic dosimeter was suitable for the field testing and measurement of time-weighted average concentrations of VOC-contaminated waters.

  20. Development of a biological dosimeter for translocation scoring based on two-color fluorescence in situ hybridization of chromosome subsets

    Energy Technology Data Exchange (ETDEWEB)

    Popp, S; Cremer, T [Heidelberg Univ. (Germany). Inst. of Human Genetics and Anthropology

    1992-03-01

    Recently fluorescence in situ hybridization protocols have been developed which allow the paining of individual chromosomes using DNA-libraries from sorted human chromosomes. This approach has the particular advantage that radiation induced chromosome translocations can be easily detected, if chromosomes of distinctly different colors take part in the translocation event. To enhance the sensitivity of this approach two metaphase chromosome subsets A and B (A: chromosome 1, 2, 4, 8, 16; B: 3, 5, 9, 10, 13) were simultaneously painted in green and red color. Counterstaining of the chromosomes with DAPI resulted in a third subset which exhibited blue fluorescence only. Green-red, green-blue and red-blue translocation chromosomes could be easily detected after irradiation of lymphocyte cultures with {sup 137}Cs-{gamma}-rays. Analyses of painted chromosomes can be combined with conventional GTG-banding analyses. This new biological dosimeter should become useful to monitor both long term effects of single irradiation events and the cumulative effects of multiple or chronic irradiation exposure. In contrast to translocation scoring based on the analysis of banded chromosomes, this new approach has the particular advantage that a rapid, automated scoring of translocations can now be envisaged. (author).

  1. Evaluation of gamma radiation cumulative exposure monitoring system in the Nuclear Technology Development Center (CDTN) with thermoluminescent dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Domingues, Danieli S.; Barreto, Alberto A.; Siqueira, Gessilane M.; Oliveira, Eugênio M.; Silva, Robson L.; Belo, Luiz Cláudio M., E-mail: danielisilva@ymail.com, E-mail: aab@cdtn.br, E-mail: gessilane.siqueira@cdtn.br, E-mail: emo@cdtn.br, E-mail: rls@cdtn.br, E-mail: lcmb@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2017-07-01

    Cumulative exposure to gamma radiation is monitored at the Nuclear Technology Development Center - CDTN, located on the campus of the Federal University of Minas Gerais in Belo Horizonte - MG, since 1986. This monitoring is part of the Institution's Environmental Monitoring Program. The measurement is carried out through the use of thermoluminescent dosimeters (TLD's), which are placed in the perimeter of the CDTN property, distanced approximately 50 m each other, and at the air sampling stations, totaling 36 sampling points. The TLDs are positioned one meter from the ground, inside a PVC pipe where they remain exposed for a period of approximately three months. The objective of this work is to present and evaluate the results of this monitoring by investigating the dose values of gamma radiation (Dose Equivalent to Photons) obtained. Another important issue presented is about some failures identified in certain periods. There were problems with the sampling methodology and changes were proposed in the shelters to avoid contact of TLDs with excess moisture, which can compromise the results and the equipment of measurement of the thermoluminescence of crystals. The change was made at a sampling point and the results were compared with the historical data in the last 30 years. (author)

  2. Evaluation of gamma radiation cumulative exposure monitoring system in the Nuclear Technology Development Center (CDTN) with thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    Domingues, Danieli S.; Barreto, Alberto A.; Siqueira, Gessilane M.; Oliveira, Eugênio M.; Silva, Robson L.; Belo, Luiz Cláudio M.

    2017-01-01

    Cumulative exposure to gamma radiation is monitored at the Nuclear Technology Development Center - CDTN, located on the campus of the Federal University of Minas Gerais in Belo Horizonte - MG, since 1986. This monitoring is part of the Institution's Environmental Monitoring Program. The measurement is carried out through the use of thermoluminescent dosimeters (TLD's), which are placed in the perimeter of the CDTN property, distanced approximately 50 m each other, and at the air sampling stations, totaling 36 sampling points. The TLDs are positioned one meter from the ground, inside a PVC pipe where they remain exposed for a period of approximately three months. The objective of this work is to present and evaluate the results of this monitoring by investigating the dose values of gamma radiation (Dose Equivalent to Photons) obtained. Another important issue presented is about some failures identified in certain periods. There were problems with the sampling methodology and changes were proposed in the shelters to avoid contact of TLDs with excess moisture, which can compromise the results and the equipment of measurement of the thermoluminescence of crystals. The change was made at a sampling point and the results were compared with the historical data in the last 30 years. (author)

  3. Dopant concentration and thermoluminescence (TL) properties of tailor-made Ge-doped SiO2 fibres

    International Nuclear Information System (INIS)

    Zahaimi, Nurul Arina; Ooi Abdullah, Mohd Haris Ridzuan; Zin, Hafiz; Abdul Rahman, Ahmad Lutfi; Hashim, Suhairul; Saripan, Mohd Iqbal; Paul, Mukul Chandra; Bradley, D.A.; Abdul Rahman, Ahmad Taufek

    2014-01-01

    Study focuses on characterisation of diverse concentrations of Ge-doped SiO 2 fibre as a potential thermoluminescence (TL) system for radiotherapy dosimetry. Irradiations were made using a linear accelerator providing 6 MV and 10 MV photon beams. Investigation has been done on various doped core diameter Ge-doped SiO 2 glass fibres such as commercial telecommunication fibres of 8 µm and 9 µm (CorActive High Tech, Canada), tailor-made fibres of 23 and 50 µm produced by the Central Glass and Ceramic Research Institute Kolkata, and tailor-made fibres of 11 µm produced by the University of Malaya Photonics Research Centre. The fibres have been characterised for TL sensitivity, reproducibility, dose- and energy-dependence. The area under the TL glow curve increases with increasing core diameter. For repeat irradiations at a fixed dose the dosimeter produces a flat response better than 4% (1SD) of the mean of the TL distribution. Minimal TL signal fading was found, less than 0.5% per day post irradiation. Linearity of TL has been observed with a correlation coefficient (r 2 ) of better than 0.980 (at 95% confidence level). For particular dopant concentrations, the least square fits show the change in TL yield, in counts per second per unit mass, obtained from 50 µm core diameter fibres irradiated at 6 MV of photon to be 8 times greater than that of 8 µm core diameter fibre. With respect to energy response, the TL yield at 10 MV decreases by∼5% compared to that at 6 MV, primarily due to the lower mass energy absorption coefficient at higher photon energy. These early results indicate that selectively screened fibres can be developed into a promising TL system, offering high spatial resolution capability and, with this, verification of complex radiotherapy dose distributions. - Highlights: • We examined the TL glow curve intensity for various diameter sizes of germanium doped silica glass fibre. • TL sensitivity increased with the increase of fibre core

  4. The TL and OSL study of hydroxyapatites for dosimetric applications

    International Nuclear Information System (INIS)

    Alencar, Marcus A. Vallim de

    2009-01-01

    The hydroxyapatite, the principal mineral component of the bone and tooth enamel, is one of the dosimetric materials that has distinguished itself in the high dose and accidents dosimetry, as well as in the dating, for the Electron Paramagnetic Resonance (EPR) technique. For this reason, the hydroxyapatite could also be used as Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) dosimeter in the dosimetry of high doses and accidents, and also in the archaeological and geological dating. This work presents a brief study of the TL and OSL behaviour of the B type synthetic carbonated hydroxyapatite, observing the possibility to use this material in TL and OSL dosimetry. The samples were irradiated to a dose of 100 Gy and 1000 Gy, and the TL and OSL measurements were obtained by the RISOE TL/OSL reader, model TL/OSL-DA-15B. The first results demonstrate the presence of three peaks in the TL glow curve in the temperatures of 100 deg C, 150 deg C and 280 deg C. The synthetic carbonated hydroxyapatite also presents an OSL signal when the sample is stimulated with blue light and a small OSL signal for stimulation with infrared light (IR). These results indicate the possibility of this synthetic carbonated hydroxyapatite to be used as dose indicator material using the TL and OSL techniques. (author)

  5. Converting Hg-1212 to Tl-2212 via Tl-Hg cation exchange in combination with Tl cation intercalation

    International Nuclear Information System (INIS)

    Zhao Hua; Wu, Judy Z

    2007-01-01

    In a cation exchange process developed recently for epitaxy of HgBa 2 CaCu 2 O 6 (Hg-1212) thin films, TlBa 2 CaCu 2 O 7 (Tl-1212) or Tl 2 Ba 2 CaCu 2 O 9 (Tl-2212) precursor films were employed as the precursor matrices and Hg-1212 was obtained by replacing Tl cations on the precursor lattice with Hg cations. The reversibility of the cation exchange dictates directly the underlying mechanism. Following our recent success in demonstrating a complete reversibility within '1212' structure, we show the conversion from Hg-1212 to Tl-2212 can be achieved via two steps: conversion from Hg-1212 to Tl-1212 followed by Tl intercalation to form double Tl-O plans in each unit cell. The demonstrated reversibility of the cation exchange process has confirmed the process is a thermal perturbation of weakly bonded cations on the lattice and the direction of the process is determined by the population ratio between the replacing cations and that to be replaced

  6. Thermoluminescent dosimeter system

    International Nuclear Information System (INIS)

    Felice, P.E.; Gonzalez, J.L.; Seidel, J.G.

    1979-01-01

    An improved thermoluminescent dosimeter system and apparatus for sensing alpha particle emission is described. A thermoluminescent body is sealed between a pair of metallized plastic films. The dosimeter is mounted within a protective inverted cup or a tube closed at one end, which is disposed in a test hole for exposure to radioactive radon gas which is indicaive of uranium deposits

  7. Calcium flouride (CaF2) from oyster shell as a raw material for thermoluminescence dosimeter

    International Nuclear Information System (INIS)

    Coloma, Lyra C.; Fanuga, Lyn N.; Ocreto, Cherries Ann; Rodriguez, Richita

    2006-03-01

    This study aims to develop a thermoluminescence dosimeter raw material made of calcium fluoride from locally available seashells that is suitable for personal radiation monitoring. Oyster shells were collected and grounded as powder samples and analyzed for calcium fluoride (CaF 2 ) content using XRF and XRD testing. Samples include pure CaF 2 , pure oyster shell, and oyster shells treated with acid. Based from the XRF results, natural oyster shell (w/ and w/o HNO 3 ) had high percentage of calcium about 49.64% and 47.45%, next to the pure calcium fluoride of 51.08%. X-ray diffractrogram shows that oyster sample had the nearest desired structure of CaF 2 compared with two seashells relative to the pure CaF 2 as standard materials. Results show that all of the natural oyster samples displayed TL emission glow curves at the temperature range 200-300 o C. It was also found that pure oyster sample has better TL response as compared to the treated ones. The researchers concluded that the calcium fluoride from oyster shells (without acid and heated) is a potentially good low-cost TLD raw material and may be used as an alternative for the much more expensive LiF dosimeters. (Authors)

  8. Tl response of KMgF{sub 3}: Lu + PTFE at ultraviolet radiation; Respuesta Tl de KMgF{sub 3}: Lu + PTFE a radiacion ultravioleta

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, P R [Instituto Nacional de Investigaciones Nucleares, A.P. 18 -1027, 11801 Mexico D.F. (Mexico); Alarcon, N G [Facultad de Quimica, Universidad Autonoma del Estado de Mexico. Paseo Tollocan, Esq. con Jesus Carranza, 50180 Toluca, Estado de Mexico (Mexico); Furetta, C; Azorin, J [Universidad Autonoma Metropolitana- Iztapalapa, San Rafael Atlixco 186, 09340 Mexico. D.F. (Mexico)

    2003-07-01

    Ionizing radiation has different types of interaction with a crystalline solid. However, only few effects are interesting to optimize some thermoluminescent (Tl) properties of certain Tl materials. This paper presents results obtained by irradiating KMgF{sub 3}: Lu + Ptfe Tl dosimeters with ultraviolet (UV) radiation previously exposed to gamma radiation. These results showed that those dosimeters not exposed previously to gamma radiation did not presented any Tl signal. Meanwhile, those previously submitted to gamma irradiation showed that their sensitivity was increased as the gamma dose increased. The glow curve of sensitized KMgF{sub 3}: Lu + Ptfe exposed to UV radiation, presented the dosimetric pea at 212 C. This makes this material to be promissory for measuring UV radiation. (Author)

  9. A population-based exposure assessment methodology for carbon monoxide: Development of a carbon monoxide passive sampler and occupational dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Apte, Michael G. [Univ. of California, Berkeley, CA (United States)

    1997-09-01

    Two devices, an occupational carbon monoxide (CO) dosimeter (LOCD), and an indoor air quality (IAQ) passive sampler were developed for use in population-based CO exposure assessment studies. CO exposure is a serious public health problem in the U.S., causing both morbidity and mortality (lifetime mortality risk approximately 10{sup -4}). Sparse data from population-based CO exposure assessments indicate that approximately 10% of the U.S. population is exposed to CO above the national ambient air quality standard. No CO exposure measurement technology is presently available for affordable population-based CO exposure assessment studies. The LOCD and IAQ Passive Sampler were tested in the laboratory and field. The palladium-molybdenum based CO sensor was designed into a compact diffusion tube sampler that can be worn. Time-weighted-average (TWA) CO exposure of the device is quantified by a simple spectrophotometric measurement. The LOCD and IAQ Passive Sampler were tested over an exposure range of 40 to 700 ppm-hours and 200 to 4200 ppm-hours, respectively. Both devices were capable of measuring precisely (relative standard deviation <20%), with low bias (<10%). The LOCD was screened for interferences by temperature, humidity, and organic and inorganic gases. Temperature effects were small in the range of 10°C to 30°C. Humidity effects were low between 20% and 90% RH. Ethylene (200 ppm) caused a positive interference and nitric oxide (50 ppm) caused a negative response without the presence of CO but not with CO.

  10. Miniature Active Space Radiation Dosimeter, Phase II

    Data.gov (United States)

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

  11. The development of an automatic scanning method for CR-39 neutron dosimeter

    International Nuclear Information System (INIS)

    Tawara, Hiroko; Miyajima, Mitsuhiro; Sasaki, Shin-ichi; Hozumi, Ken-ichi

    1989-01-01

    A method of measuring low level neutron dose has been developed with CR-39 track detectors using an automatic scanning system. It is composed of the optical microscope with a video camera, an image processor and a personal computer. The focus point of the microscope and the X-Y stage are controlled from the computer. The minimum detectable neutron dose is estimated at 4.6 mrem in the uniform field of neutron with equivalent energy spectrum to Am-Be source from the results of automatic measurements. (author)

  12. Developments of directional detectors with NaI(Tl)/BGO scintillators

    International Nuclear Information System (INIS)

    Shirakawa, Y.

    2004-01-01

    This paper describes directional gamma ray detectors with different types of scintillators. The detectors, which positively increase directional sensitivity to incident gamma rays, have been developed to measure directions, energies and counts of gamma rays, and to search for radioactive materials such as orphan radioisotopes or contaminations. Experimental results have shown that proposed directional detectors have a potential for practical use in real fields and will contribute to radiation protection and safety

  13. Development of a dosimeter for high doses assessment based on Alanine/EPR

    International Nuclear Information System (INIS)

    Galante, O.L.; Rodrigues, O. Jr.; Campos, L.L.

    2000-01-01

    The increasing use of radiation sources of high activity for industrial and medical applications becomes important the research and the development of detectors and dosimetric methods for quality control of the applied doses. This work presents the current stage of the research at IPEN/CNEN-SP that has as objective the development of a standard dosimetric system for high doses assessment based on the alanine as radiation detector and electron paramagnetic resonance (EPR) as measurement technique. The developed system consists of the cylindrical container built in polyethylene of high density and the detector element based on DL-alanine commercially available. For the detector preparation different binding materials such as paraffin and acetate polyvinyl solution (pva) and also the use of a polyethylene tube of low density with 3.2 mm of external diameter, 2 mm of internal diameter and 30 mm of length were tested to provide the easier preparation method and the most sensitive detector. For the alanine + paraffin detector it was used 80% of alanine and 20% of paraffin, for the alanine + pva detector it was used 70% of alanine and 30% of pva solution, and pure alanine was encapsulated, compacted and sealed in the case of the polyethylene tube. The obtained results with respect to handling, packing and construction easiness showed that the polyethylene tube presents all characteristics to obtain of a good detector element. The validation of the dosimetric system was carried out with gamma radiation of the cobalt-60 with doses in the range between 0.2 Gy to 200 kGy. Type tests such as fading, lowest detection limit, reproducibility and energy dependence of the sign EPR were performed. All measurements were carried out at room temperature using a spectrometer of electron paramagnetic resonance (EPR) Bruker model MXE. Taking into account the results obtained: linearity of the EPR signal between 10 Gy and 50 kGy, reproducibility better than 3%, low fading associated with

  14. Development of a Real-time Personal Dosimeter System and its Application to Hanul Unit-4

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kidoo; Cho, Moonhyung; Son, Jungkwon [Korea Hydro Nuclear Power Co., Seoul (Korea, Republic of)

    2013-10-15

    The main reasons to adopt the system are to minimize unnecessary exposure, to calculate one's dose faster, to provide a possible alternatives of personnel such as radiation safety manager. The KHNP's Remote radiation Monitoring System (KRMS) is characterized as integrated, less bulky, lighter comparing to existing instrument although it have multifunction of real-time dosimetry and voice communication. After laboratory test in Central Research Institute (CRI) and field test in Hanbit unit-3 and 4, KRMS was applied to main radiation works in Hanul unit-4. KHNP-CRI has developed real-time personal dose monitoring system and applied to Hanul overhaul which include steam generator replacement. It took 5 days to install the system in reactor building and the optimal location for the repeater was 3 points at 122ft and 3 points at 100ft. Owing to the optimization of repeater and high sensitivity antenna, there was no shaded area of wireless network and no loss of dose data in spite of wearing lead jacket. The average deviation of personal dose received by KRMS and existing ADR is about 2%, which tell us it matches well. The lessons learned in Hanul unit-4 are it needs simplification of operating system and it requires a function to be able to check battery level at remote area.

  15. Development of a low-cost-high-sensitivity Compton camera using CsI (Tl) scintillators (γI)

    Energy Technology Data Exchange (ETDEWEB)

    Kagaya, M., E-mail: 13nd401n@vc.ibaraki.ac.jp [College of Science, Ibaraki University, 2-1-1 Bunkyo, Mito City, Ibaraki 310-8512 (Japan); Open-It consortium (Japan); Katagiri, H. [College of Science, Ibaraki University, 2-1-1 Bunkyo, Mito City, Ibaraki 310-8512 (Japan); Open-It consortium (Japan); Enomoto, R. [Institute for Cosmic Ray Research, University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa City, Chiba 277-8582 (Japan); Open-It consortium (Japan); Hanafusa, R.; Hosokawa, M.; Itoh, Y. [Fuji Electric, 1 Fujimachi, Hino City, Tokyo 191-8502 (Japan); Muraishi, H. [School of Allied Health Science, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara City, Kanagawa 252-0373 (Japan); Open-It consortium (Japan); Nakayama, K. [College of Science, Ibaraki University, 2-1-1 Bunkyo, Mito City, Ibaraki 310-8512 (Japan); Open-It consortium (Japan); Satoh, K. [Shinsei Corporation, 4-9-1 Nihonbashi-honcho, Chuo-ku, Tokyo 103-0023 (Japan); Takeda, T. [School of Allied Health Science, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara City, Kanagawa 252-0373 (Japan); Tanaka, M.M.; Uchida, T. [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba City, Ibaraki 305-0801 (Japan); Open-It consortium (Japan); Watanabe, T. [School of Allied Health Science, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara City, Kanagawa 252-0373 (Japan); Open-It consortium (Japan); Yanagita, S.; Yoshida, T.; Umehara, K. [College of Science, Ibaraki University, 2-1-1 Bunkyo, Mito City, Ibaraki 310-8512 (Japan); Open-It consortium (Japan)

    2015-12-21

    We have developed a novel low-cost gamma-ray imaging Compton camera γI that has a high detection efficiency. Our motivation for the development of this detector was to measure the arrival directions of gamma rays produced by radioactive nuclides that were released by the Fukushima Daiichi nuclear power plant accident in 2011. The detector comprises two arrays of inorganic scintillation detectors, which act as a scatterer and an absorber. Each array has eight scintillation detectors, each comprising a large CsI (Tl) scintillator cube of side 3.5 cm, which is inexpensive and has a good energy resolution. Energies deposited by the Compton scattered electrons and subsequent photoelectric absorption, measured by each scintillation counter, are used for image reconstruction. The angular resolution was found to be 3.5° after using an image-sharpening technique. With this angular resolution, we can resolve a 1 m{sup 2} radiation hot spot that is located at a distance of 10 m from the detector with a wide field of view of 1 sr. Moreover, the detection efficiency 0.68 cps/MBq at 1 m for 662 keV (7.6 cps/μSv/h) is sufficient for measuring low-level contamination (i.e., less than 1 μSv/h) corresponding to typical values in large areas of eastern Japan. In addition to the laboratory tests, the imaging capability of our detector was verified in various regions with dose rates less than 1 μSv/h (e.g., Fukushima city).

  16. Evaluation of personal dosimeters

    International Nuclear Information System (INIS)

    Correa, C. A.

    2007-01-01

    This work makes a screening of the different types of dosimeters present in the international market, to provide operative dosimetry of individual monitoring to measure Hp(10) and Hp(0,07)-specifically for external radiation gamma and beta, as well as to give knowledge of advances of passive and operative dosimetry, and the changes in the regulatory policy relative to these aspects. The data has been extracted from several providers of dosimeters, and the importance has been stressed in a good election of the dosimeter before its use, as well as the important advances in these equipment. (Author) 14 refs

  17. The LLNL CR-39 personnel neutron dosimeter

    International Nuclear Information System (INIS)

    Hankins, D.E.; Homann, S.; Westermark, J.

    1987-01-01

    We developed a personnel neutron dosimetry system based on the electrochemical etching of CR-39 plastic at elevated temperatures. The doses obtained using this dosimeter system are more accurate than those obtained using other dosimetry systems, especially when varied neutron spectra are encountered. This CR-39 dosimetry system does not have the severe energy dependence that exists with albedo neutron dosimeters or the fading and reading problems encountered with NTA film. 3 refs., 4 figs

  18. Use of wrist albedo neutron dosimeters

    International Nuclear Information System (INIS)

    Hankins, D.E.

    1983-01-01

    We are developing a wrist dosimeter that can be used to measure the exposure at the wrist to x-rays, gamma rays, beta-particles, thermal neutrons and fast neutrons. It consists of a modified Hankins Type albedo neutron dosimeter and also contains three pieces of CR-39 plastic. ABS plastic in the form of an elongated hemisphere provides the beta and low energy x-ray shielding necessary to meet the requirement of depth dose measurements at 1 cm. The dosimeter has a beta window located in the side of the hemisphere oriented towards an object being held in the hands. A TLD 600 is positioned under the 1 cm thick ABS plastic and is used to measure the thermal neutron dose. At present we are using Velcro straps to hold the dosimeter on the inside of the wrist. 9 figures

  19. Composite Resin Dosimeters: A New Concept and Design for a Fibrous Color Dosimeter.

    Science.gov (United States)

    Kinashi, Kenji; Iwata, Takato; Tsuchida, Hayato; Sakai, Wataru; Tsutsumi, Naoto

    2018-04-11

    Polystyrene (PS)-based composite microfibers combined with a photochromic spiropyran dye, 1,3,3-trimethylindolino-6'-nitrobenzopyrylospiran (6-nitro BIPS), and a photostimulable phosphor, europium-doped barium fluorochloride (BaFCl:Eu 2+ ), were developed for the detection of X-ray exposure doses on the order of approximately 1 Gy. To produce the PS-based composite microfibers, we employed a forcespinning method that embeds a high concentration of phosphor in PS in a safe, inexpensive, and simple procedure. On the basis of the optimization of the forcespinning process, fibrous color dosimeters with a high radiation dose sensitivity of 1.2-4.4 Gy were fabricated. The color of the dosimeters was found to transition from white to blue in response to X-ray exposure. The optimized fibrous color dosimeter, made from a solution having a PS/6-nitro BIPS/BaFCl:Eu 2+ /C 2 Cl 4 ratio of 7.0/0.21/28.0/28.0 (wt %) and produced with a 290 mm distance between the needle and collectors, a 0.34 mm 23 G needle nozzle, and a spinneret rotational rate of 3000 rpm, exhibited sensitivity to a dose as low as 1.2 Gy. To realize practical applications, we manufactured the optimized fibrous color dosimeter into a clothlike color dosimeter. The clothlike color dosimeter was mounted on a stuffed bear, and its coloring behavior was demonstrated upon X-ray exposure. After exposure with X-ray, a blue colored and shaped in the form of the letter "[Formula: see text]" clearly appeared on the surface of the clothlike color dosimeter. The proposed fibrous color dosimeters having excellent workability will be an unprecedented dosimetry and contributed to all industries utilizing radiation dosimeters. This new fibrous "composite resin dosimeter" should be able to replace traditional, wearable, and individual radiation dose monitoring devices, such as film badges.

  20. Tl response of KMgF3: Lu + PTFE at ultraviolet radiation

    International Nuclear Information System (INIS)

    Gonzalez, P.R.; Alarcon, N.G.; Furetta, C.; Azorin, J.

    2003-01-01

    Ionizing radiation has different types of interaction with a crystalline solid. However, only few effects are interesting to optimize some thermoluminescent (Tl) properties of certain Tl materials. This paper presents results obtained by irradiating KMgF 3 : Lu + Ptfe Tl dosimeters with ultraviolet (UV) radiation previously exposed to gamma radiation. These results showed that those dosimeters not exposed previously to gamma radiation did not presented any Tl signal. Meanwhile, those previously submitted to gamma irradiation showed that their sensitivity was increased as the gamma dose increased. The glow curve of sensitized KMgF 3 : Lu + Ptfe exposed to UV radiation, presented the dosimetric pea at 212 C. This makes this material to be promissory for measuring UV radiation. (Author)

  1. Bronchial dosimeter for radon progeny

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, T.K.; Yu, K.N.; Nikezic, D.; Haque, A.K.M.M. [City University of Hong Kong, Hong Kong (China); Vucic, D. [Faculty of Technology, University of Nis, Lescovac (Yugoslavia)

    2000-05-01

    Traditionally, assessments of the bronchial dose from radon progeny were carried out by measuring the unattached fraction (f{sub p}) of potential alpha energy concentration (PAEC), the total PAEC, activity median diameters (AMDs) and equilibrium factor, and then using dosimetric lung models. A breakthrough was proposed by Hopke et al. (1990) to use multiple metal wire screens to mimic the deposition properties of radon progeny in the nasal (N) and tracheobronchial (T-B) regions directly. In particular, they were successful in using four layers of 400-mesh wire screens with a face velocity of 12 cm s{sup -1} for the simulation of radon progeny deposition in the T-B region. Oberstedt and Vanmarcke (1995) carried out precise calibrations for the system, and named the system as the 'bronchial dosimeter'. Based on these, Yu and Guan (1998) proposed a portable bronchial dosimeter similar to a normal measurement system for radon progeny or PAEC and consisted of only a single sampler and employed only one 400-mesh wire screen and one filter. However, all these 'bronchial dosimeters' in fact only determined the fraction of potential alpha energy from radon progeny deposited in the T-B region, which required certain assumptions and calculations to further give the final bronchial dose. In the present work, a true 'bronchial dosimeter' was designed, which consisted of three 400-mesh wire screens and a filter. With a face velocity of 11 cm s{sup -1}, the deposition pattern on the wire screens was found to satisfactorily match the variation of the dose conversion factor (in the unit of mSv/WLM) with the size of radon progeny from 1 to 1000 nm. In this way, this bronchial dosimeter directly gave the bronchial dose from the alpha counts recorded on the wire-screens and the filter paper. With the development of this bronchial dosimeter, the present practice of 'dose estimation' from large-scale radon surveys can be replaced by large

  2. Application of solid dosimeter to radiation control

    International Nuclear Information System (INIS)

    Tsujimoto, Tadashi

    1988-01-01

    Individual exposure dose measuring devices are used to measure the dose of each person in facilities using radiations. Major devices of this type currently used in Japan include the film badge, thermoluminescence dosimeter, portable radiation dosimeter and fluorescent glass dosimeter. All of these devices except the portable radiation dosimeter are of a solid type. Various portable-type spatial dose rate measuring devices, generally called survey meters, are available to determine the spatial distribution of radiations. Major survey meters incorporates an ionization chamber, GM counter tube or scintillation counter, while BF 3 counting tubes are available for neutron measurement. Of these, the scintillation dosimeter is of a solid type. A new scintillation survey meter has recently been developed which incorporated a discrimination bias modulation circuit. Dosimeters incorporating an ionization chamber or a GM counter tube are generally used as portable alarms. Recently, a new solid-type alarm has been developed which incorporates a solicon radiation detector. Microcomputers are also used for self-diagnosis, data processing, automatic calibration, etc. (Nogami, K.)

  3. Activation analysis of thallium in urine using the 203Tl(n,2n) 202Tl reaction

    International Nuclear Information System (INIS)

    Korob, R.O.; Cohen, I.M.; Lage, M.; Baro, G.B.

    1976-04-01

    The method developed by the authors of thallium determination in human urine, based on the 203 Tl(n,2n) 202 Tl reaction followed by chemical separation and measurement of the produced 202 Tl by gamma spectrometry, is described. Its application in some cases of intoxication by thallium is reported. The advantages and limitations of the described technique are discussed. (author) [es

  4. A fibre optic dosimeter customised for brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-04-15

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

  5. Development of a new dosimeter of EPR based on lactose; Desarrollo de un nuevo dosimetro de RPE basado en lactosa

    Energy Technology Data Exchange (ETDEWEB)

    Cruz C, L.; Torijano C, E.; Azorin N, J.; Aguirre G, F. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Cruz Z, E., E-mail: eftc@xanum.uam.mx [UNAM, Instituto de Ciencias Nucleares, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2014-08-15

    50 years have passed since was proposed using the amino acid alanine as dosimeter advantage the phenomenon of electron paramagnetic resonance (EPR); this dosimetric method has reached a highly competitive level regarding others dosimetry classic methods, for example the thermoluminescence or the use of Fricke dosimeters, to measure high dose of radiation. In this type of materials, the free radicals induced by the radiation are stable and their concentration is proportional to the absorbed dose may be determined by the amplitude pick to pick of the first derived of the EPR absorption spectrum. The obtained results studying the EPR response of lactose tablets elaborated in the Universidad Autonoma Metropolitana, Unidad Iztapalapa are presented. The tablets were irradiated with gamma radiation of {sup 60}Co in the irradiator Gamma beam 651-Pt of the Instituto de Ciencias Nucleares de la Universidad Nacional Autonoma de Mexico to a dose rate of 8 kGy-h{sup -1} and their EPR response in a EPR spectrometer e-scan Bruker. The obtained response in function of the dose was lineal in the interval of 1 at 10 kGy. The lactose sensibility was compared with the l-alanine, used as reference, and the result was consistently 0.25 of this. Due to the linearity shown in the interval of used dose and their low production cost, we conclude that the lactose is a promissory option for the dosimetry of high dose of radiation. (author)

  6. Radon daughter dosimeter

    International Nuclear Information System (INIS)

    Durkin, J.

    1977-01-01

    This patent describes a portable radon daughter dosimeter unit used to measure radon gas alpha daughters in ambient air. These measurements can then be related to preselected preestablished standards contained in a remote central readout unit. The dosimeter unit is adapted to be worn by an operator in areas having alpha particle radiation such as in uranium mines. Within the dosimeter is a detector head housing having a filter head and a solid state surface barrier radiation detector; an air pump to get air to the detector head; a self contained portable power supply for the unit; and electronic circuitry to process detected charged electrons from the detector head to convert and count their pulses representatives of two alpha radon emitter daughters. These counted pulses are in binary form and are sent to a readout unit where a numerical readout displays the result in terms of working level-hours

  7. Radon daughter dosimeter

    International Nuclear Information System (INIS)

    Durkin, J.

    1977-01-01

    A portable radon daughter dosimeter unit used to measure Radon gas alpha daughters in ambient air is described. These measurements can then be related to preselected preestablished standards contained in a remote central readout unit. The dosimeter unit is adapted to be worn by an operator in areas having alpha particle radiation such as uranium mines. Within the dosimeter is a detector head housing having a filter head and a solid state surface barrier radiation detector; an air pump to get air to the detector head; a self contained portable power supply for the unit; and electronic circuitry to process detected charged electrons from the detector head to convert and count their pulses representatives of two alpha radon emitter daughters. These counted pulses are in binary form and are sent to a readout unit where a numerical readout diplays the result in terms of working level-hours

  8. Development of dark-striped field mice, Apodemus agrarius coreae, as a biological dosimeter in a radio-ecological monitoring system: 2. Survival rates and hematology

    International Nuclear Information System (INIS)

    Kim, Hee Sun; Kim, Chong Soon; Nishmura, Y.

    2005-01-01

    Regarding the management of nuclear power plants and the installation of facilities for radiation waste storage: social concerns over radiation safety are increasing. To understand how environmental radiation affects on human beings, the development of an reasonable monitoring system is required. The existing radio-environmental surveillance systems can be classified into physical and biological monitoring systems. The wild small animals and livestocks were reported to be effective biological indicators of environmental radiation This study investigated the possibility of using dark-striped field mice as a biological dosimetric model to assess the effect of radiation on the human environments. For this study, the criteria for the biological dosimeters of environmental radiation were established as the following: first, it should be an animal from a clear background of species; second, it should inhabit a broad range of areas and in considerable numbers; third, it should maintain identical ecological characteristics; fourth, it should be cohabitating with humans; fifth, it should have been consuming food found in their habitat; and finally, it should indicate a clear doseresponse relationship with high sensitivity. Based on such criteria, this study investigated the possibility of using dark-striped field mice as an effective biological dosimeter. Primarily, their species were classified based on their morphological external characteristics and isoenzymic patterns. The taxonomically classified darkstriped field mice, A. agrarius coreae, were then irradiated to investigate their radiation sensitivity based on the survival rate and hematology in this study

  9. Development of dark-striped field mice, Apodemus agrarius coreae, as a biological dosimeter in a radio-ecological monitoring system: 2. Survival rates and hematology

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hee Sun; Kim, Chong Soon [Korea Hydro and Nuclear Power Co., Ltd., Daejeon (Korea, Republic of); Nishmura, Y. [National Institute of Radiological Sciences, Chiba (Japan)

    2005-07-01

    Regarding the management of nuclear power plants and the installation of facilities for radiation waste storage: social concerns over radiation safety are increasing. To understand how environmental radiation affects on human beings, the development of an reasonable monitoring system is required. The existing radio-environmental surveillance systems can be classified into physical and biological monitoring systems. The wild small animals and livestocks were reported to be effective biological indicators of environmental radiation This study investigated the possibility of using dark-striped field mice as a biological dosimetric model to assess the effect of radiation on the human environments. For this study, the criteria for the biological dosimeters of environmental radiation were established as the following: first, it should be an animal from a clear background of species; second, it should inhabit a broad range of areas and in considerable numbers; third, it should maintain identical ecological characteristics; fourth, it should be cohabitating with humans; fifth, it should have been consuming food found in their habitat; and finally, it should indicate a clear doseresponse relationship with high sensitivity. Based on such criteria, this study investigated the possibility of using dark-striped field mice as an effective biological dosimeter. Primarily, their species were classified based on their morphological external characteristics and isoenzymic patterns. The taxonomically classified darkstriped field mice, A. agrarius coreae, were then irradiated to investigate their radiation sensitivity based on the survival rate and hematology in this study.

  10. Development of a Bio-Equivalent Ultraviolet Dosimeter to Monitor the Capacity for Vitamin D Synthesis of Sunlight Final Report CRADA No. TC02086.0

    Energy Technology Data Exchange (ETDEWEB)

    Smith, C. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wood, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-15

    This project represents a collaborative effort between Lawrence Livermore National Security, LLC as manager and operator of Lawrence Livermore National Laboratory (LLNL) and Rhyolite Technology Group, Inc. (Rhyolite) to develop concepts and designs for a consumer ultraviolet (UV) biodosimeter based on the human biochemistry of Vitamin D synthesis. Rhyolite was established to engage in product development, licensing and consulting for the manufacture and supply of new products worldwide. Rhyolite worked jointly with LLNL and the Kiev Institute of Physics (KIP) in Ukraine to leverage previously developed UV sensor technologies by extending the previous work into commercially viable products. The project consisted primarily of the scientific, engineering and business activities needed to develop the UV bio-dosimeter for applications that include health and industrial measurement of ultraviolet radiation.

  11. Radiation dosimeter assembly

    International Nuclear Information System (INIS)

    Seidel, J.G.

    1982-01-01

    A technique is disclosed for securing a thermoluminescent radiation dosimeter, used for monitoring underground radon gas in uranium prospecting, to a cup-like support member made of heavy gauge aluminum foil. A metalized film, consisting of an aluminum layer and a high tensile strength plastic layer, covers an aperture in the support members for the dosimeter. The film is secured by a high temperature adhesive to the support member, and both are capable of withstanding an annealing temperature of up to 300 0 C

  12. Personnel ionizing radiation dosimeter

    International Nuclear Information System (INIS)

    Williams, R.A.

    1975-01-01

    A dosimeter and method for use by personnel working in an area of mixed ionizing radiation fields for measuring and/or determining the effective energy of x- and gamma radiation; beta, x-, and gamma radiation dose equivalent to the surface of the body; beta, x-, and gamma radiation dose equivalent at a depth in the body; the presence of slow neutron, fast neutron dose equivalent; and orientation of the person wearing the dosimeter to the source of radiation is disclosed. Optionally integrated into this device and method are improved means for determining neutron energy spectrum and absorbed dose from fission gamma and neutron radiation resulting from accidental criticality

  13. Thermoluminescence dosimeter reader

    International Nuclear Information System (INIS)

    Robertson, M.E.A.; Marshall, J.; Brabants, J.A.P.; Davies, M.E.

    1975-01-01

    An electric circuit arrangement is described including a photomultiplier tube and a high voltage source therefor also includes a feedback loop from the output of the tube to the high voltage source, and loop providing automatic gain stabilization for the tube. The arrangement is used in a dosimeter reader to provide sensitivity correction for the reader each time the reader is to be used

  14. Fiber-optic dosimeters for radiation therapy

    Science.gov (United States)

    Li, Enbang; Archer, James

    2017-10-01

    According to the figures provided by the World Health Organization, cancer is a leading cause of death worldwide, accounting for 8.8 million deaths in 2015. Radiation therapy, which uses x-rays to destroy or injure cancer cells, has become one of the most important modalities to treat the primary cancer or advanced cancer. The newly developed microbeam radiation therapy (MRT), which uses highly collimated, quasi-parallel arrays of x-ray microbeams (typically 50 μm wide and separated by 400 μm) produced by synchrotron sources, represents a new paradigm in radiotherapy and has shown great promise in pre-clinical studies on different animal models. Measurements of the absorbed dose distribution of microbeams are vitally important for clinical acceptance of MRT and for developing quality assurance systems for MRT, hence are a challenging and important task for radiation dosimetry. On the other hand, during the traditional LINAC based radiotherapy and breast cancer brachytherapy, skin dose measurements and treatment planning also require a high spatial resolution, tissue equivalent, on-line dosimeter that is both economical and highly reliable. Such a dosimeter currently does not exist and remains a challenge in the development of radiation dosimetry. High resolution, water equivalent, optical and passive x-ray dosimeters have been developed and constructed by using plastic scintillators and optical fibers. The dosimeters have peak edge-on spatial resolutions ranging from 50 to 500 microns in one dimension, with a 10 micron resolution dosimeter under development. The developed fiber-optic dosimeters have been test with both LINAC and synchrotron x-ray beams. This work demonstrates that water-equivalent and high spatial resolution radiation detection can be achieved with scintillators and optical fiber systems. Among other advantages, the developed fiber-optic probes are also passive, energy independent, and radiation hard.

  15. Measurement of the dose by dispersed radiation in a lineal accelerator using thermoluminescent dosimeters of CaSO4:Dy

    International Nuclear Information System (INIS)

    Chavez C, N.; Torijano, E.; Azorin, J.; Herrera, A.

    2014-08-01

    The thermoluminescence (Tl) is based on the principle of the luminescent in a material when is heated below their incandescence temperature. Is a technique very used in dosimetry that is based on the property that have most of the crystalline materials regarding the storage of the energy that they absorb when are exposed to the ionizing radiations. When this material has been irradiated previously, the radioactive energy that contains is liberated in form of light. In general, the principles that govern the thermoluminescence are in essence the same of those responsible for all the luminescent processes and, this way, the thermoluminescence is one of the processes that are part of the luminescence phenomenon. For this work, the dispersed radiation was measured in the therapy area of the lineal accelerator of medical use type Elekta, using thermoluminescent dosimeters of CaSO 4 :Dy + Ptfe developed and elaborated in the Universidad Autonoma Metropolitana, Unidad Iztapalapa. With the dosimeters already characterized and calibrated, we proceeded to measure the dispersed radiation being a patient in treatment. The results showed values for the dispersed radiation the order of a third of the dose received by the patient on the treatment table at 30 cm of the direct beam and the order of a hundredth in the control area (4 m of the direct beam, approximately). The conclusion is that the thermoluminescent dosimeters of CaSO 4 : Dy + Ptfe are appropriate to measure dispersed radiation dose in radiotherapy. (author)

  16. Influence of dose history on thermoluminescence response of Ge-doped silica optical fibre dosimeters

    International Nuclear Information System (INIS)

    Moradi, F.; Mahdiraji, G.A.; Dermosesian, E.; Khandaker, M.U.; Ung, N.M.; Mahamd Adikan, F.R.; Amin, Y.M.

    2017-01-01

    Nowadays, silica based optical fibres show enough potential to be used as TL dosimeters in different applications. Reuse of optical fibre as a practical dosimeter demands to complete removal of accumulated doses via previous irradiations. This work investigates the existence and/or effect of remnant doses in fibre dosimeter from the previous irradiations, and proposes a method to control this artifact. A single mode Ge-doped optical fibre is used as TL radiation sensor, while a well calibrated Gammacell with 60 Co source is used for irradiations. The effect of irradiation history on the TL response of optical fibres is surveyed extensively for doses ranged from 1 to 1000 Gy. The results show that the absorbed dose history in a fibre affects its response in the next irradiation cycles. It is shown that a dose history of around 100 Gy can increase the response of optical fibre by a factor of 1.72. The effect of annealing at higher temperatures on stabilizing the fibre response is also examined and results revealed that another alteration in the structure of trapping states occurs in glass medium which can change the sensitivity of fibres. Preservation of the sensitivity during successive irradiation cycles can be achieved by a proper annealing procedure accompanied by a pre-dose treatment. - Highlights: • Influence of dose history on TL characteristics of fibre dosimeter is explored. • The phenomenon behind the TL variation caused by dose history is discussed. • Effect of annealing temperature on performance of fibre dosimeter is studied. • Pre-treatment methods for mitigating variation in reproducibility are proposed.

  17. Tl response of LiF: Mg, Cu, P + PTFE (Mexico) and GR200A (China) dosemeters

    International Nuclear Information System (INIS)

    Gonzalez M, P.R.; Azorin N, J.; Furetta, C.

    2003-01-01

    TLD-100 was the commercial dosemeter more known since some decades ago. This dosemeter was considered for many research groups as the reference material for developing new Tl materials for ionizing radiation dosimetry. Actually it seems that TLD-100 is going to be replaced by the Chinese material GR200A, as reference material due that this material in addition to be considered as a tissue equivalent material, is 30 to 35 times more sensitive that TLD- 100. Results of the study of the Tl response of LiF: Mg, Cu, P + Ptfe developed at ININ-Mexico, comparing them with those of GR200A are presented. These results showed that the sensitivity (s = Tl intensity/weight x dose) to gamma radiation of the LiF: Mg, Cu, P + Ptfe dosimeters was 4.34 meanwhile that of the commercial dosemeter was 3.41. Detection threshold of the dosemeters studied was 2.22 and 0.52 μGy respectively Repeatability after 10 cycles Irradiation-reading-annealing was ±1.39% and ±1.86% respectively. Both types of dosemeters presented a linear response as a function of gamma radiation in the range from 0.02 mGy and 100 Gy. (Author)

  18. Design and development of wide energy neutron REM equivalent spectrometer-dosimeters based on polycarbonates and Cr-39

    International Nuclear Information System (INIS)

    Faermann, S.

    1985-03-01

    This work describes a system composed of a Rem response personnel neutron dosemeter, based on boron radiators and a polycarbonate track detector, for monitoring dose equivalents in the energy range 1 eV to 14 MeV, an electrochemical etching system for revealing damage sites in solid state track etch detectors, a reader for magnifying the etched pits and a microprocessor for evaluating the dose equivalents and their uncertainties. The performance and directional dependence of the dosemeter when exposed to monoenergetic and polyenergetic neutron fields in the epithermal and fast energy regions are discussed. Saturation effects in polycarbonate foils are presented and a comparison is made between the response of polycarbonate and CR-39 foils, used as passive detectors in the dosemeter. A new passive miniature fast neutron spectrometer-dosimeter is also described. The device is based on the detection of proton tracks by electrochemical etching of CR-39 foils covered with thin polyethylene layers of different thicknesses. By means of this device it is possible to assess the fast neutron energy spectrum in 10 energy intervals in the energy range 0.5-15 MeV. Dose equivalents can be determined in the dose equivalent range 20 mRem to 8 Rem, approximately (author)

  19. Development of a dosimetric system for the quality control of breast cancer treatments

    International Nuclear Information System (INIS)

    Chaves, Roberio C.; Crispim, Verginia R.; Santos, Delano B.V.

    2013-01-01

    A system for evaluating the values of absorbed dose in breast teletherapy was developed, using thermoluminescent dosimeters (TLD-100), to compare them to those provided by Therapy planning system. A breast phantom was made to distribute the dosimeters TL shaped chip in breast volume and irradiate it under the same conditions of planning. Three different techniques of teletherapy were considered: one with irradiation from a therapy unit of 60 Co and two with an X-ray beam coming from a 6 MV linear accelerator. Doses measures allowed checking that the performance of the quality control system used in breast cancer treatment is appropriate, since the planned doses differed about 1.5% of the responses provided by TL dosimeters

  20. Automated Calibration of Dosimeters for Diagnostic Radiology

    International Nuclear Information System (INIS)

    Romero Acosta, A.; Gutierrez Lores, S.

    2015-01-01

    Calibration of dosimeters for diagnostic radiology includes current and charge measurements, which are often repetitive. However, these measurements are usually done using modern electrometers, which are equipped with an RS-232 interface that enables instrument control from a computer. This paper presents an automated system aimed to the measurements for the calibration of dosimeters used in diagnostic radiology. A software application was developed, in order to achieve the acquisition of the electric charge readings, measured values of the monitor chamber, calculation of the calibration coefficient and issue of a calibration certificate. A primary data record file is filled and stored in the computer hard disk. The calibration method used was calibration by substitution. With this system, a better control over the calibration process is achieved and the need for human intervention is reduced. the automated system will be used in the calibration of dosimeters for diagnostic radiology at the Cuban Secondary Standard Dosimetry Laboratory of the Center for Radiation Protection and Hygiene. (Author)

  1. Automating the personnel dosimeter monitoring program

    International Nuclear Information System (INIS)

    Compston, M.W.

    1982-12-01

    The personnel dosimetry monitoring program at the Portsmouth uranium enrichment facility has been improved by using thermoluminescent dosimetry to monitor for ionizing radiation exposure, and by automating most of the operations and all of the associated information handling. A thermoluminescent dosimeter (TLD) card, worn by personnel inside security badges, stores the energy of ionizing radiation. The dosimeters are changed-out periodically and are loaded 150 cards at a time into an automated reader-processor. The resulting data is recorded and filed into a useful form by computer programming developed for this purpose

  2. CRRES dosimeter simulations

    International Nuclear Information System (INIS)

    Auchampaugh, G.; Cayton, T.

    1993-04-01

    Conflicting data have been obtained from electron instruments aboard CRRES (Combined Release and Radiation Effects Satellite). To gain insight and to help in the interpretation of the data, we have calculated electron- and proton-flux and dose response functions for the four domes of the CRRES dosimeters using the Los Alamos Monte Carlo radiation transport codes. The response functions were calculated for electron and proton energies representative of those present in the space radiation environment. We also calculated the response of the dosimeters to a model radiation environment for orbit 607, which occurred on April 1, 1991 and compared the results to the measured values. The electron and proton components of the radiation environment were calculated using the solar maximum versions of the AE8 and AP8 models, namely, AE8MAX and AP8MAX. To facilitate the second task, we wrote two FORTRAN programs (CRRESunderscoreSIMP for AP8MAX and CRRESunderscoreSIME for AE8MAX) to read in a standard CRRES data file and to produce a comparison file of the calculated and measured values for all four dosimeter domes.The FORTRAN code will be available to the Phillips Laboratory for their use in making comparisons to other orbital data

  3. Development and validation of a protocol for field validation of passive dosimeters for ethylene oxide excursion limit monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Puskar, M.A.; Szopinski, F.G.; Hecker, L.H. (Corporate Industrial Hygiene Laboratory, Abbott Laboratories, North Chicago, IL (USA))

    1991-04-01

    An exposure and analysis protocol is described for the field validation of passive dosimeters for ethylene oxide (EtO) excursion limit monitoring. The protocol calls for the use of a field exposure chamber with concurrent sampling using Tedlar air-sampling bags. The bags are analyzed immediately after sampling by gas chromatography with flame ionization detection (GC-FID). The chamber design allows all monitors to be exposed for the exact same time in the field. The sampling and analysis procedure not only determines the actual concentration of EtO present during the monitor's exposure but estimates if concentrations of EtO vary from point to point in the monitor array during the exposure. In chamber operation, the accuracy of the standard generator used to calibrate the GC-FID was independently verified in the field by the standard additions method. The sampling bias of the sampling train was determined to be -3.5% in the 2.4 ppm to 14.3 ppm concentration range. To estimate the stability of collected EtO samples in Tedlar bags, the rate of EtO loss in the bags was determined to be 0.011 ppm/hr at 2.57 ppm and 0.066 ppm/hr at 8.07 ppm. Sampling bias of the passive methods by additional EtO exposure of the monitors in the closed chamber after sampling and during purging was determined to be +1.5%. The Tedlar bag sampling method with subsequent GC-FID determination demonstrated a coefficient of variation of 1.8% at 2.43 ppm.

  4. OSL and TL of Resistors of Mobile Phones for Retrospective Accident Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. I.; Kim, J. L.; Pradhan, A. S.; Chang, I.; Kim, B. H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    Optically stimulated luminescence (OSL) and thermoluminescence (TL) of ubiquitous materials continue to draw wider attention for individual dosimetry in nuclear and radiation accidents. Use of ubiquitous objects for radiation dosimetry is preferred because the affected persons in such unexpected events are usually not covered by personal dosimetry services and do not carry personal dosimeters. Often accident sites do not have area monitoring system in place. As the main concern of the dosimetry is health effects, a quick distinction of level of exposures of the affected persons for the required medical care becomes important in all accidents involving radiation. Both in large scale nuclear accidents such Fukushima, Chernobyl or Hiroshima and Nagasaki where large population around the accident site get exposed to radiation (evacuation is based on doses) and in smaller but panicky events, such as misuse of radiological exposure device (RED), radiological dispersive device (RDD: 'Dirty Bomb'), improvised nuclear device (IND) and deliberate dispersal of radioactive contaminants, a need for an ubiquitous personal dosimeter is well recognized. As biological dosimetry systems are yet to become viable for measurements of doses with required accuracy and speed, use of physical dosimeters is often explored. Among the various types of physical dosimetry systems, use of TL and OSL by processing common material such as bricks or tiles and measuring the doses cumulated for long periods of time has already become an accepted tool for large scale nuclear accidents such as Hiroshima and Nagasaki or Chernobyl involving higher doses. In the other potential cases of unexpected situations where the doses encountered could be much lower (even to escape the range of remotely installed area monitors), the need to measure even the low doses in shortest possible time becomes important. It is often realized that in such situations, the main problem could become the panic at the

  5. OSL and TL of Resistors of Mobile Phones for Retrospective Accident Dosimetry

    International Nuclear Information System (INIS)

    Lee, J. I.; Kim, J. L.; Pradhan, A. S.; Chang, I.; Kim, B. H.

    2012-01-01

    Optically stimulated luminescence (OSL) and thermoluminescence (TL) of ubiquitous materials continue to draw wider attention for individual dosimetry in nuclear and radiation accidents. Use of ubiquitous objects for radiation dosimetry is preferred because the affected persons in such unexpected events are usually not covered by personal dosimetry services and do not carry personal dosimeters. Often accident sites do not have area monitoring system in place. As the main concern of the dosimetry is health effects, a quick distinction of level of exposures of the affected persons for the required medical care becomes important in all accidents involving radiation. Both in large scale nuclear accidents such Fukushima, Chernobyl or Hiroshima and Nagasaki where large population around the accident site get exposed to radiation (evacuation is based on doses) and in smaller but panicky events, such as misuse of radiological exposure device (RED), radiological dispersive device (RDD: 'Dirty Bomb'), improvised nuclear device (IND) and deliberate dispersal of radioactive contaminants, a need for an ubiquitous personal dosimeter is well recognized. As biological dosimetry systems are yet to become viable for measurements of doses with required accuracy and speed, use of physical dosimeters is often explored. Among the various types of physical dosimetry systems, use of TL and OSL by processing common material such as bricks or tiles and measuring the doses cumulated for long periods of time has already become an accepted tool for large scale nuclear accidents such as Hiroshima and Nagasaki or Chernobyl involving higher doses. In the other potential cases of unexpected situations where the doses encountered could be much lower (even to escape the range of remotely installed area monitors), the need to measure even the low doses in shortest possible time becomes important. It is often realized that in such situations, the main problem could become the panic at the work place

  6. The neutron diffraction of molten TlCl, TlBr, and TlI

    International Nuclear Information System (INIS)

    Satow, T.; Uemura, O.; Hoshino, K.; Watanabe, T.

    1984-01-01

    Structure factors S(K) for liquid TlCl, TlBr, and TlI are determined by neutron diffraction measurements. Atomic radial distribution functions (RDF) derived from S(K) are presented. All RDF values are slightly smaller than those of their solid state counter parts. Results show that TlX has a tendency not to retain cesium-chloride type local order, but to take sodium-chloride type order when melting

  7. Characteristics of radiophotoluminescent glass dosimeters

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-07-01

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

  8. Expanding the Teaching Commons: Making the Case for a New Perspective on SoTL

    Directory of Open Access Journals (Sweden)

    Kim A. Case, PhD

    2013-08-01

    Full Text Available As a reflection on O’Meara, Terosky, and Neumann’s (2011 work on scholarship of teaching and learning (SoTL faculty development, this essay describes the benefits of SoTL to individual faculty and university goals. In support and expansion of arguments advanced by O’Meara et al., this work calls for the use of SoTL faculty development to promote the shared teaching commons, active recruitment of new SoTL scholars, institutionalization of SoTL values, and integration of SoTL initiatives in both teaching centers and research-focused development offices.

  9. Fast fluence measurement for JOYO irradiation field using niobium dosimeter

    International Nuclear Information System (INIS)

    Ito, Chikara

    2004-03-01

    Neutron fluence and spectrum are key parameters in various irradiation tests and material surveillance tests so they need to be evaluated accurately. The reactor dosimetry test has been conducted by the multiple foil activation method, and a niobium dosimeter has been developed for measurement of fast neutron fluence in the experimental fast reactor JOYO. The inelastic scattering reaction of 93 Nb has a low threshold energy, about 30 keV, and the energy distribution of reaction cross section is similar to the displacement cross section for iron. Therefore, a niobium dosimeter is suitable for evaluation of the fast neutron fluence and the displacement per atom for iron. Moreover, a niobium dosimeter is suited to measure neutron fluence in long-term irradiation test because 93 Nb, which is produced by the reaction, has a long half-life (16.4 years). This study established a high precision measurement technique using the niobium reaction rate. The effect of self-absorption was decreased by the solution and evaporation to dryness of niobium dosimeter. The dosimeter weight was precisely measured using the inductively coupled plasma mass spectrometer. This technique was applied to JOYO dosimetry. The fast neutron fluences (E > 0.1 MeV) found by measuring the reaction rate in the niobium dosimeter were compared with the values evaluated using the multiple foil activation method. The ratio of measured fast neutron fluences by means of niobium dosimeter and multiple foil activation method range from 0.97 to 1.03 and agree within the experimental uncertainty. The measurement errors of fast neutron fluence by niobium dosimeter range from 4.5% (fuel region) to 10.1% (in-vessel storage rack). As a result of this study, the high precision measurement of fast neutron fluence by niobium dosimeters was confirmed. The accuracy of fast reactor dosimetry will be improved by application of niobium dosimeters to the irradiation tests in the JOYO MK-III core. (author)

  10. Hanford personnel dosimeter supporting studies FY-1981

    International Nuclear Information System (INIS)

    1982-08-01

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

  11. Selfcalibrated alanine/EPR dosimeters. A new generation of solid state/EPR dosimeters

    International Nuclear Information System (INIS)

    Yordanov, N.D.; Gancheva, V.

    1999-01-01

    Alanine/EPR dosimeters are well established as secondary, reference dosimeters for high-energy radiation. However, there are various sources of uncertainty in the evaluation of absorbed dose. This arises primarily from the necessity to calibrate each EPR spectrometer and each batch of dosimeters before their use. In order to overcome this disadvantage, a new generation alanine/EPR dosimeter has been developed, and its possibilities as a radiation detector are reported. Principally, it is a mixture of alanine, some quantity of EPR active substance, and a binding material. The EPR active substance, acting as an internal EPR standard, is chosen to have EPR parameters which are independent of the irradiation dose. The simultaneous recording of the spectra of both the sample and the standard under the same experimental conditions and the estimation of the ratio I alanine /I Mn as a function of the absorbed dose strongly reduces the uncertainties. The response of these dosimeters for 60 Co γ-radiation exhibits excellent linearity and reproducibility in the range of absorbed dose, 10 2 - 5 x 10 4 Gy. (author)

  12. Radiation dosimeter utilizing the thermoluminescence of lithium fluoride.

    Science.gov (United States)

    CAMERON, J R; DANIELS, F; JOHNSON, N; KENNEY, G

    1961-08-04

    A dosimeter, with little wavelength dependence and large useful energy range for electromagnetic radiation, which is simple to use and read, has been developed. It appears to have applications in personnel monitoring as well as radiation research.

  13. Device for the automatic evaluation of pencil dosimeters

    International Nuclear Information System (INIS)

    Schallopp, B.

    1976-01-01

    In connenction with the automation of radiation protection in nuclear power plants, an automatic reading device has been developed for the direct input of the readings of pencil dosimeters into a computer. Voltage measurements would be simple but are excluded, because the internal electrode of the dosimeter may not be touched, for operational reasons. This paper describes an optical/electronic conversion device in which the reading of the dosimeter is projected onto a Vidicon, scanned, and converted into a digital signal for output to the computer. (orig.) [de

  14. Development of a dosimetric system for the quality control of breast cancer treatments; Desenvolvimento de um sistema dosimetrico para o controle de qualidade nos tratamentos de cancer de mama

    Energy Technology Data Exchange (ETDEWEB)

    Chaves, Roberio C.; Crispim, Verginia R., E-mail: rchaves@nuclear.ufrj.br, E-mail: verginia@nuclear.ufrj.br [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEN/COPPE/lUFRJ), RJ (Brazil). Programa de Pos-Graduacao em Engenharia Nuclear; Rosa, Luiz A.R. da, E-mail: Irosa@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN), Rio de Janeiro, RJ (Brazil); Santos, Delano B.V., E-mail: delano@inca.gov.br [Instituto Nacional do Cancer (INCA/MS), Rio de Janeiro, RJ (Brazil)

    2013-11-01

    A system for evaluating the values of absorbed dose in breast teletherapy was developed, using thermoluminescent dosimeters (TLD-100), to compare them to those provided by Therapy planning system. A breast phantom was made to distribute the dosimeters TL shaped chip in breast volume and irradiate it under the same conditions of planning. Three different techniques of teletherapy were considered: one with irradiation from a therapy unit of {sup 60}Co and two with an X-ray beam coming from a 6 MV linear accelerator. Doses measures allowed checking that the performance of the quality control system used in breast cancer treatment is appropriate, since the planned doses differed about 1.5% of the responses provided by TL dosimeters.

  15. An approved personal dosimetry service based on an electronic dosimeter

    International Nuclear Information System (INIS)

    Marshall, T.O.; Bartlett, D.T.; Burgess, P.H.; Campbell, J.I.; Hill, C.E.; Pook, E.A.; Sandford, D.J.

    1991-01-01

    At the Second Conference on Radiation Protection and Dosimetry a paper was presented which, in part, announced the development of an electronic dosimeter to be undertaken in the UK by the National Radiological Protection Board (NRPB) and Siemens Plessey Controls Ltd. This dosimeter was to be of a standard suitable for use as the basis of an approved personal dosimetry service for photon and beta radiations. The project has progressed extremely well and dosimeters and readers are about to become commercially available. The system and the specification of the dosimeter are presented. The NRPB is in the process of applying for approval by the Health and Safety Executive (HSE) to operate as personal monitoring service based on this dosimeter. As part of the approval procedure the dosimeter is being type tested and is also undergoing an HSE performance test and wearer trials. The tests and the wearer trials are described and a summary of the results to date presented. The way in which the service will be organized and operated is described and a comparison is made between the running of the service and others based on passive dosimeters at NRPB

  16. Development of the 60Co gamma-ray standard field for therapy-level dosimeter calibration in terms of absorbed dose to water (ND,W)

    International Nuclear Information System (INIS)

    Fukumura, Akifumi; Mizuno, Hideyuki; Fukahori, Mai; Sakata, Suoh

    2013-01-01

    A primary standard for the absorbed dose rate to water in a 60 Co gamma-ray field was established at National Metrology Institute of Japan (NMIJ) in fiscal year 2011. Then, a 60 Co gamma-ray standard field for therapy-level dosimeter calibration in terms of absorbed dose to water was developed at National Institute of Radiological Sciences (NIRS) as a secondary standard dosimetry laboratory (SSDL). The results of an International Atomic Energy Agency (IAEA)/World Health Organization (WHO) TLD SSDL audit demonstrated that there was good agreement between NIRS stated absorbed dose to water and IAEA measurements. The IAEA guide based on the International Organization for Standardization (ISO) standard was used to estimate the relative expanded uncertainty of the calibration factor for a therapy-level Farmer type ionization chamber in terms of absorbed dose to water (N D,W ) with the new field. The uncertainty of N D,W was estimated to be 1.1% (k=2), which corresponds to approximately one third of the value determined in the existing air kerma field. The dissemination of traceability of the calibration factor determined in the new field is expected to diminish the uncertainty of dose delivered to patients significantly. (author)

  17. Direct reading dosimeter

    International Nuclear Information System (INIS)

    Thomson, I.

    1985-01-01

    This invention is a direct reading dosimeter which is light, small enough to be worn on a person, and measures both dose rates and total dose. It is based on a semiconductor sensor. The gate threshold voltage change rather than absolute value is measured and displayed as a direct reading of the dose rate. This is effected by continuously switching the gate of an MOS transistor from positive to negative bias. The output can directly drive a digital readout or trigger an audible alarm. The sensor device can be a MOSFET, bipolar transistor, or MOSFET capacitor which has its electrical characteristics change due to the trapped charge in the insulating layer of the device

  18. Colorimetric gas dosimeter

    International Nuclear Information System (INIS)

    McConnaughey, P.W.; McKee, E.S.

    1984-01-01

    A gas dosimeter comprises a stack of porous sheets, impregnated with a reagent that changes color on contact with the gas to be determined, contained in a housing which has an opening to expose one end of the stack to the atmosphere to be tested. The gas to be determined penetrates by diffusion the layers of porous sheets, causing the sheets in the stack to change color sequentially from the end of the stack exposed to the atmosphere. The degree of penetration through the layers of porous sheets is a function of dosage exposure. The housing may be transparent with each superposed sheet in the stack being larger than the adjacent underlying sheet, so that each sheet is visible through the housing endwall

  19. The intelligence of dosimeter for ionization radiation

    International Nuclear Information System (INIS)

    He Jinglun

    1992-01-01

    The connection of dosimeter with microcomputer system is described, which has the functions of sampling, data handling, display and printing dose values in legal units of measurement. The accuracy and speed of measurement for dosimeters are also raised, thereby the dosimeters are made to have intelligence and the application range of dosimeter is enlarged

  20. Silver nitrate based gel dosimeter

    International Nuclear Information System (INIS)

    Titus, D; Samuel, E J J; Srinivasan, K; Roopan, S M; Madhu, C S

    2017-01-01

    A new radiochromic gel dosimeter based on silver nitrate and a normoxic gel dosimeter was investigated using UV-Visible spectrophotometry in the clinical dose range. Gamma radiation induced the synthesis of silver nanoparticles in the gel and is confirmed from the UV-Visible spectrum which shows an absorbance peak at around 450 nm. The dose response function of the dosimeter is found to be linear upto12Gy. In addition, the gel samples were found to be stable which were kept under refrigeration. (paper)

  1. Evaluation of personal integrating dosimeters

    International Nuclear Information System (INIS)

    Correa, C.A.; Bisauta, Mauricio A.

    2007-01-01

    The objective of this work is to analyze the different types of dosimeters present in the international market that are used to provide personal dose monitoring, specifically for external gamma and beta radiation, Hp(10) and Hp (0,07), as well as to add comments of advances in the field of passive and operative dosimetry, and the changes that are being produced in the regulating policy in other countries regarding the use of this devices. The technical specification of each dosimeter has been extracted of different catalogues of products. To conclude, the importance has been stressed in a proper selection of dosimeters with its advantages and disadvantages before its use. (author) [es

  2. Brain SPECT with Tl-201 DDC

    International Nuclear Information System (INIS)

    Bruine, J.F. de.

    1988-01-01

    The development, animal and human experiments and the first clinical results of a new blood flow tracer thallium-201 diethyldithiocarbamate (Tl-201 DDC) are discussed for functional brain imaging with single-photon emission computed tomography (SPECT). 325 refs.; 43 figs.; 22 tabs

  3. Heater design for reading radiation dosimeters

    International Nuclear Information System (INIS)

    Seidel, J.G.; Felice, P.E.

    1982-01-01

    The nichrome heating element of a conventional dosimeter reading apparatus has been redesigned to include a flat-bottomed depression big enough to hold a thermoluminescent dosimeter. A thin glass plate is positioned in the recess on top of the dosimeter to retain it in the recess during the heating and reading process. This technique of securing the dosimeter in contact with the heating element avoids physical scratching or damage to the dosimeter

  4. LOW-COST PERSONNEL DOSIMETER.

    Science.gov (United States)

    specification was achieved by simplifying and improving the basic Bendix dosimeter design, using plastics for component parts, minimizing direct labor, and making the instrument suitable for automated processing and assembly. (Author)

  5. Citizen's dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Klemic, Gladys [Naperville, IL; Bailey, Paul [Chicago, IL; Breheny, Cecilia [Yonkers, NY

    2008-09-02

    The present invention relates to a citizen's dosimeter. More specifically, the invention relates to a small, portable, personal dosimetry device designed to be used in the wake of a event involving a Radiological Dispersal Device (RDD), Improvised Nuclear Device (IND), or other event resulting in the contamination of large area with radioactive material or where on site personal dosimetry is required. The card sized dosimeter generally comprises: a lower card layer, the lower card body having an inner and outer side; a upper card layer, the layer card having an inner and outer side; an optically stimulated luminescent material (OSLM), wherein the OSLM is sandwiched between the inner side of the lower card layer and the inner side of the upper card layer during dosimeter radiation recording, a shutter means for exposing at least one side of the OSLM for dosimeter readout; and an energy compensation filter attached to the outer sides of the lower and upper card layers.

  6. Investigating potential physicochemical errors in polymer gel dosimeters

    International Nuclear Information System (INIS)

    Sedaghat, Mahbod; Lepage, Martin; Bujold, Rachel

    2011-01-01

    Measurement errors in polymer gel dosimetry can originate either during irradiation or scanning. One concern related to the exothermic nature of polymerization reaction was that the heat released in polymer gel dosimeters during irradiation modifies their dose response. In this paper, the effect of heat released from the exothermal polymerization reaction on the dose response of a number of dosimeters was studied. In addition, we investigated whether heat-generated geometric distortion existed in newly proposed gel dosimeters that contain highly thermoresponsive polymers. Our results suggest that despite a significant internal temperature increase in some gel compositions, their dose responses are not affected when oxygen is well expelled mechanically from the gel mixture. We also report on significant pre-irradiation instability in some recently developed polymer gel dosimeters but that geometric distortions were not observed. Data obtained by a set of small calibration vials are compared to those obtained from larger phantoms, and potential physicochemical causes of deviations between them are identified.

  7. Investigating potential physicochemical errors in polymer gel dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Sedaghat, Mahbod; Lepage, Martin [Centre d' imagerie moleculaire de Sherbrooke, Departement de medecine nucleaire et radiobiologie, Universite de Sherbrooke, Sherbrooke, QC (Canada); Bujold, Rachel, E-mail: martin.lepage@usherbrooke.ca [Service de radio-oncologie, Centre hospitalier universitaire de Sherbrooke, Sherbrooke, QC (Canada)

    2011-09-21

    Measurement errors in polymer gel dosimetry can originate either during irradiation or scanning. One concern related to the exothermic nature of polymerization reaction was that the heat released in polymer gel dosimeters during irradiation modifies their dose response. In this paper, the effect of heat released from the exothermal polymerization reaction on the dose response of a number of dosimeters was studied. In addition, we investigated whether heat-generated geometric distortion existed in newly proposed gel dosimeters that contain highly thermoresponsive polymers. Our results suggest that despite a significant internal temperature increase in some gel compositions, their dose responses are not affected when oxygen is well expelled mechanically from the gel mixture. We also report on significant pre-irradiation instability in some recently developed polymer gel dosimeters but that geometric distortions were not observed. Data obtained by a set of small calibration vials are compared to those obtained from larger phantoms, and potential physicochemical causes of deviations between them are identified.

  8. An Emergency Dosimeter for Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Braun, J; Nilsson, R

    1960-05-15

    A neutron dosimeter suitable for single emergency exposures is described. The dosimeter is furnished with detectors for thermal, epi-thermal and fast neutrons. This means that three of the constants by which the spectrum of the incident neutron flux is approximated, can be determined. The dose calculated from these approximated spectra is compared to the dose from spectra obtained in different standard spectra of types which may be expected in a radiation accident.

  9. Review of Fricke gel dosimeters

    International Nuclear Information System (INIS)

    Schreiner, L J

    2004-01-01

    The innovation of adding a gel matrix to the traditional Fricke dosimeter to stabilize geometric information established the field of gel dosimetry for radiation therapy. A discussion of Fricke gels provides an overview of the issues that determine the dose response of all gel dosimeters in general. In this paper we review some of the features of Fricke systems to illustrate these issues and, in addition, to motivate renewed clinical interest in Fricke gels

  10. Development of pulsed stimulation and Photon Timer attachments to the Risø TL/OSL reader

    DEFF Research Database (Denmark)

    Lapp, Torben; Jain, Mayank; Ankjærgaard, Christina

    2009-01-01

    in the OSL/IRSL process, a Photon Timer attachment to the Risø reader has been developed which measures data at 100 ps resolution. Furthermore a post-processing program has been developed to present the data in a compressed 3D form that gives a useful overview of the data before further analysis of relevant...

  11. Spectral measurements of loess TL

    International Nuclear Information System (INIS)

    Rendell, H.M.; Mann, S.J.; Townsend, P.D.

    1988-01-01

    Variations in thermoluminescence (TL) glow curves are reported for two loess samples when examined with broad band filters in the range 275-650 nm. Samples show striking differences in bleaching behaviour, when their TL emissions are observed in the u.v., blue, green and yellow spectral regions. The age estimates, given by the equivalent dose (ED) values, differ by up to a factor of two for analyses using the green and u.v. TL signals. These ED values also vary with prolonged room temperature storage between the bleaching and irradiation steps. The anomalies in the bleaching behaviour are interpreted in terms of changes in TL efficiency. The results have major implications for the regeneration method of TL dating for these fine-grained sediments and suggest that reliable dates obtained by it may be fortuitous. (author)

  12. 201Tl heart studies

    International Nuclear Information System (INIS)

    Bell, R.L.

    1976-01-01

    At the annual meeting of the Society of Nuclear Medicine there was a preponderance of papers dealing with the heart. The most impressive papers detailed the use of monovalent cation 201 Tl in the evaluation of coronary artery disease. Thallium-201 behaves like potassium in that it enters heart muscle quickly and persists in that organ for several hours. It is unlike most radioactive potassium analogues used for heart studies in that: (1) its gamma energy peaks (69 keV and 80 keV) are more easily collimated with resultant image improvement, (2) its physical half life of 72 hours is sufficiently short to attain high counting rates without too much radiation and is sufficiently long so that storage is not prohibitive, (3) its short half life and lack of Beta radiation results in lower radiation to the patient, and (4) its uptake in heart is greater and uptake in liver and stomach less than other potassium analogues

  13. TL and OSL dosimetric properties of Opal gemstone for gamma radiation dosimetry

    International Nuclear Information System (INIS)

    Antonio, Patrícia L.; Gronchi, Claudia C.; Oliveira, Raquel A.P.; Khoury, Helen J.; Caldas, Linda V.E.

    2016-01-01

    In this work, the response of the natural material Opal was studied in relation to its thermoluminescence (TL) and optically stimulated luminescence (OSL), after exposure to the gamma radiation of a "6"0Co source. The structure of the powdered Opal was verified using the X-ray diffraction, scanning electronic microscopy and energy-dispersive X-ray spectroscopy techniques. The material, in its stone form, was turned into powder and mixed to Teflon (also in powder) in three different concentrations, and then pellets were manufactured. The aim of this work was to evaluate the response of these pellets in high-doses of gamma radiation beams, and to observe their possible application as dosimeters, using the TL and OSL techniques. The dosimetric properties of the samples were analyzed by means of different tests, as: TL emission curves and OSL signal decay curves, reproducibility of TL and OSL response, minimum detectable dose, TL and OSL dose–response curves (5 Gy–10 kGy), and fading. The results obtained in this work, for the TL and OSL phenomena, demonstrated that the pellets of Opal + Teflon present an adequate performance e possibility of use as dosimeters in beams of high-dose gamma radiation. - Highlights: • The XRD, SEM and EDX techniques were used to investigate powdered Opal. • Pellets of three different concentrations of Opal and Teflon were studied. • The dosimetric properties of the Opal + Teflon pellets were verified. • TL and OSL techniques were used to analyze the characteristics of the pellets. • Pellets of concentration of 2:1 (Opal:Teflon) presented the most adequate results.

  14. Small is beautiful: SAIC's new dosimeter

    International Nuclear Information System (INIS)

    Benson, R.G.

    1991-01-01

    Science Applications International Corporation (California) has developed an energy-compensated Geiger tube in a package the size of a small pocket pager. In fact, the whole dosimeter measures just 48mm x 72mm x 17mm. The rugged, lightweight unit is sensitive enough to record radiation ranging from low background levels caused by the earth's surface, the sun, or cosmic radiation, to beyond lethal dose levels. The PD-1 provides dose measurement, dose rate measurement, and ''chip'' functions. A chirper sounds each time a specified dose is accumulated, and the chirp increments are defined by the user. A dosimeter reader provides a simple interface for bi-directional communication with host PC. The Geiger tube provides improved accuracy over a wider energy range than current solid state devices. Features such as long battery life, long calibration life (two years or longer), and easy calibration procedure should help to simplify the work of health physicists overseeing dosimetry management programmes. (author)

  15. Digital neutron dosimeter

    International Nuclear Information System (INIS)

    Ramondetta, P.W.; Groeber, E.O.Jr.

    1978-01-01

    Design features for a portable battery-operated neutron dosimeter are described. The system employs a 50-mil PIN detector diode, whose forward voltage increases with exposure to fast neutrons. Because this change is permanent and cumulative, the system is able to integrate small doses (from 0 to 1000 rad) over long periods of time. The system is temperature compensated over its operating range of -40 C to +52C. Display accuracies of +-20 rad for readings below 100 rad and +-20% for readings above 100 rad are maintained throughout the range. Temperature correction is performed digitally after an initial analog-to-digital conversion of both the forward diode voltage and the ambient temperature. System flexibility is promoted with the use of a replaceable ROM for the final voltage-to-dose conversion table. This digital approach to temperature compensation, combined with the extensive use of CMOS circuitry, suggests the use of custom large-scale integration as a means of further reducing system weight and size. This possibility, as well as others, is discussed as a means of reducing system size. Test and evaluation results are also included. (author)

  16. The Calvet calorimetric dosimeter

    International Nuclear Information System (INIS)

    Puig, J.R.; Romano, F.

    1965-01-01

    This report describes a dosimeter based on the conduction calorimetry principle, and designed to operate in swimming-pool type nuclear reactors. The properties of the apparatus are as follows: 1 - the measurement is independent of the specific heat of the calorimetric elements; 2 - each calorimetric element is fitted with an electrical calibration; 3 - the apparatus is made up of two independent calorimetric elements; 4 - the nature of the calorimetric elements makes it possible to analyse the radiation received; 5 - the measurable intensities of the absorbed radiation vary from 4 to 4000 M/rads per hour; 6 - the sensitive part of the apparatus is fitted inside a cylinder 5 cm high and 2 cm in diameter. One pre-production unit made up of graphite and beryllium cores has been tried out in the reactor Siloe with radiation intensities of about 1 to 2 watts per gram. It absorbed an accumulated dose of 1.2*1O 12 rads without any weaknesses appearing. (authors) [fr

  17. Personnel radiation dosimetry laboratory accreditation programme for thermoluminescent dosimeters : a proposal

    International Nuclear Information System (INIS)

    Bhatt, B.C.; Srivastava, J.K.; Iyer, P.S.; Venkatraman, G.

    1993-01-01

    Accreditation for thermoluminescent dosimeters is the process of evaluating a programme intending to use TL personnel dosimeters to measure, report and record dose equivalents received by radiation workers. In order to test the technical competence for conducting personnel dosimetry service as well as to decentralize personnel monitoring service, it has been proposed by Radiological Physics Division (RPhD) to accredit some of the laboratories, in the country. The objectives of this accreditation programme are: (i) to give recognition to competent dosimetry processors, and (ii) to provide periodic evaluation of dosimetry processors, including review of internal quality assurance programme to improve the quality of personnel dosimetry processing. The scientific support for the accreditation programme will be provided by the scientific staff from Radiological Physics Division (RPhD) and Radiation Protection Services Division (RPSD). This paper describes operational and technical requirements for the Personnel Radiation Dosimetry Laboratory Accreditation Programme for Thermoluminescent Dosimeters for Personnel Dosimetry Processors. Besides, many technical documents dealing with the TL Personnel Dosimeter System have been prepared. (author). 5 refs., 2 figs

  18. Performance evaluation of a colorimetric hydrazine dosimeter

    Science.gov (United States)

    Brenner, Karen P.; Rose-Pehrsson, Susan L.

    1994-06-01

    A dosimeter for real-time, colorimetric detection of hydrazine in air has been developed. The passive badge consists of a dosimeter card containing a vanillin solution coated on a thin paper substrate. The active patch consists of a thick cellulose substrate coated with a vanillin solution. When placed in a plastic sample holder attached to a personnel pump, up to 5 L/min can be drawn through the active badge substrate. Through a condensation reaction, vanillin reacts with hydrazine to form a colored product that absorbs in the visible region. The hydrazone formed in the reaction is yellow; its intensity is proportional to the dose. When exposed passively to hydrazine, the experimental detection limit is less than 20 ppb-hrs. Extrapolated results indicate a detection limit of less than 5 ppb-hrs for long sampling periods. Actively sampling of hydrazine vapors gives an experimental detection limit of less than 100 ppb-L at a sample rate of 5 L/min. Relative humidity effects on badge response were minor. High humidity enhanced the color development on the vanillin badge; while low humidity had no effect on badge response. Interference testing of the dosimeters revealed a tobacco smoke interference. Preliminary shelf life tests indicated no decrease in sensitivity to hydrazine when stored at room temperature for 6 months.

  19. Conceptual design of the SMART dosimeter

    Science.gov (United States)

    Johnson, Erik B.; Vogel, Sam; Frank, Rebecca; Stoddard, Graham; Vera, Alonzo; Alexander, David; Christian, James

    2017-08-01

    Active dosimeters for astronauts and space weather monitors are critical tools for mitigating radiation induced health issues or system failure on capital equipment. Commercial spaceflight, deep space flight, and satellites require smarter, smaller, and lower power dosimeters. There are a number of instruments with flight heritage, yet as identified in NASA's roadmaps, these technologies do not lend themselves to a viable solution for active dosimetry for an astronaut, particularly for deep space missions. For future missions, nano- and micro-satellites will require compact instruments that will accurately assess the radiation hazard without consuming major resources on the spacecraft. RMD has developed the methods for growing an advanced scintillation material called phenylcarbazole, which provides pulse shape discrimination between protons and electrons. When used in combination with an anti-coincidence detector system, an assessment of the dose from charged ions and neutral particles can be determined. This is valuable as damage on a system (such as silicon or tissue) is dependent on the particle species. Using this crystal with readout electronics developed in partnership with COSMIAC at the University of New Mexico, the design of the Small Mixed field Autonomous Radiation Tracker (SMART) Dosimeter consists of a low-power analog to digital conversion scheme with low-power digital signal processing algorithms, which are to be implemented within a compact system on a chip, such as the Xilinx Zynq series. A review of the conceptual design is presented.

  20. Stable Chemical Dosimeters for Partial Reconstruction of Nuclear Accident Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Dvornik, I.; Zec, U.; Baric, M.; Razem, D. [Ruder Boskovic Nuclear Institute, Zagreb, Yugoslavia (Croatia)

    1969-10-15

    The application of chemical dosimeters, tissue equivalent with respect to gamma rays and neutrons, is proposed for dosimetric topography of the space around nuclear devices in case of accidents. The dosimeters in the form of sealed glass ampoules have sufficient sensitivity and long-term stability and are evaluated or checked directly by conventional spectrophotometry. The sensitivity, expressed as yield per rad, is approximately equal for gamma rays and neutrons. The resolution in both cases is about one rad, and the range is up to several thousand rads. The precision of dosimetry is {+-} 1 rad or {+-} 2%, whichever is higher. In free space and unshielded the dosimeter measures the total rad-absorbed dose delivered by gamma rays and neutrons, i.e. the first collision gamma plus neutron dose. If used on- or in-phantom, especially if several dosimeters are disposed within and around the same phantom, it can give important data about the amount of the neutron component of the dose and about the effective mean energy of incident neutrons. The neutron component of the dose can be directly measured if the gamma dosimeter is used together with the chemical dosimeter. The experiments giving the change of optical density per rad and the radiation chemical yield with respect to the absorbed dose delivered by 14-MeV neutrons are described in detail. The possibility is also mentioned of applying the dosimeter as a very sensitive monitor for thermal neutrons, which is due to the chlorine content of 4.73% and activation to {sup 38}Cl. The opinion is expressed that this dosimeter deserves some attention as a part of future planning and development work on area and personnel accidental dosimetry systems. (author)

  1. Improvement of routes and production of CaSO4-based dosimeters with unusual doping

    International Nuclear Information System (INIS)

    Junot, Danilo Oliveira

    2017-01-01

    The widespread use of ionizing radiation in medicine and industry, associated with the known risks that this type of radiation can cause, has motivated the search for new radiation detectors, seeking improvements in the dosimetric characteristics and in the cost of production in comparison with commercial dosimeters disseminated. The motivation of this work is, therefore, to produce new thermoluminescent detectors through improved routes. Unusual elements in CaSO 4 matrix doping, such as terbium (Tb) and ytterbium (Yb), were used as dopants in this matrix, as well as the europium (Eu), the thulium (Tm) and the silver (Ag), resulting in samples of CaSO 4 :Eu,Tb, CaSO 4 :Tb,Yb, CaSO 4 :Tm,Ag and CaSO 4 :Eu,Ag that were prepared by means of an adaptation of the method developed by Yamashita (1971). The route of synthesis is based on the mixture of calcium carbonate (CaCO 3 ) and dopant oxide (except for silver, incorporated in the form of metallic nanoparticles) in a solution of sulfuric acid. The mixture is heated until all the acid evaporates and only the powder of the material remains. In this route, the sulfuric acid is collected and can be reused. The phosphors produced were characterized by X-ray diffraction and radioluminescence techniques. The silver particles, produced by the polyol method, were characterized by scanning electron microscopy. Composites were obtained from the addition of Teflon to the phosphors. The thermoluminescence (TL) and the optically stimulated luminescence (OSL) of the new materials produced were investigated. Thermoluminescent characteristics such as sensitivity, linearity, reproducibility, minimum detectable dose, kinetic order and fading were evaluated and discussed. The CaSO 4 :Tb,Eu composites showed TL glow curves with peaks at temperatures of 170 °C, 270 °C and 340 °C. The CaSO 4 :Tb,Yb composites presented TL glow curves with peaks at temperatures of 90 °C, 160 °C, 240 °C and 340 °C. CaSO 4 :Tm showed peaks at

  2. DNA adducts as molecular dosimeters

    International Nuclear Information System (INIS)

    Lucier, G.W.

    1990-01-01

    There is compelling evidence that DNA adducts play an important role in the actions of many pulmonary carcinogens. During the last ten years sensitive methods (antibodies and 32 P-postlabeling) have been developed that permit detection of DNA adducts in tissues of animals or humans exposed to low levels of some genotoxic carcinogens. This capability has led to approaches designed to more reliably estimate the shape of the dose-response curve in the low dose region for a few carcinogens. Moreover, dosimetry comparisions can, in some cases, be made between animals and humans which help in judging the adequacy of animal models for human risk assessments. There are several points that need to be considered in the evaluation of DNA adducts as a molecular dosimeter. For example, DNA adduct formation is only one of many events that are needed for tumor development and some potent carcinogens do not form DNA adducts; i.e., TCDD. Other issues that need to be considered are DNA adduct heterogeneity, DNA repair, relationship of DNA adducts to somatic mutation and cell specificity in DNA adduct formation and persistence. Molecular epidemiology studies often require quantitation of adducts in cells such as lymphocytes which may or may not be reliable surrogates for adduct concentrations in target issues. In summary, accurate quantitation of low levels of DNA adducts may provide data useful in species to species extrapolation of risk including the development of more meaningful human monitoring programs

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

    International Nuclear Information System (INIS)

    Dong, Kyung-Rae; Kweon, Dae Cheol; Chung, Woon-Kwan; Goo, Eun-Hoe; Dieter, Kevin; Choe, Chong-Hwan

    2011-01-01

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

  4. Characterization of Thymol blue Radiochromic dosimeters for high dose applications

    Directory of Open Access Journals (Sweden)

    Feras M. Aldweri

    2018-03-01

    Full Text Available Thymol blue (TB solutions and Thymol blue Polyvinyl Alcohol (TB-PVA films have been introduced as Radiochromic dosimeter for high dose applications. The dosimeters were irradiated with gamma ray (60Co source from 5 to 30 kGy for film, and from 0.150 kGy to 4 kGy for solution. The optical density of unirradiated and irradiated TB solution as well as TB-PVA film dosimeters were studied in terms of absorbance at 434 nm using UV/VIS spectrophotometer. The effects of scan temperature, light pre-gamma irradiation, dose rate, relative humidity and stability of the absorbance of solutions and films after irradiation were investigated. We found the dose sensitivity of TB solution and TB-PVA film dosimeters increases significantly with increases of the absorbed dose as well as with the increases of TB dye concentrations. The useful dose range of developed TB solutions and TB-PVA films dosimeters is in the range 0.125–1 kGy and of 5–20 kGy, respectively. Keywords: Dose sensitivity, Radio-chromic dosimeter, Thymol blue, Absorbance, Concentrations

  5. Investigation of thermoluminescence properties of mobile phone screen displays as dosimeters for accidental dosimetry

    International Nuclear Information System (INIS)

    Mrozik, Anna; Marczewska, B.; Bilski, P.; Kłosowski, M.

    2014-01-01

    The rapid assessment of the radiation dose after unexpected exposure is a task of accidental dosimetry. In case of a radiological accident glasses originating from mobile phone screens, placed usually near the human body, could be used as emergency thermoluminescent (TL) personal dosimeters. The time between irradiation and TL readout is crucial and therefore preparation of the mobile phone screens and their readout conditions should be optimized. The influence of the samples etching, bleaching and selection of the optical filters based on measurement of the emission spectrum of irradiated glass samples during heating for different types of mobile phones were the subjects of our investigation. Obtained results showed that glasses extracted from different brands of mobile phones have different dosimetric properties but all of them give a luminescent signal which can be used to calculate the dose. - Highlights: • Application of acids mixture for more effective glass samples etching. • Bleaching can be performed not only by blue but also by UV light. • The readout with BG39 optical filter improves the TL signal intensity. • The glass samples from touch mobile phones are worse emergency TL dosimeters

  6. High-precision mass measurements of neutron-deficient Tl isotopes at ISOLTRAP and the development of an ultra-stable voltage source for the PENTATRAP experiment

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Christine

    2015-01-14

    Atomic masses and hence binding energies of nuclides are of great importance for studies of nuclear structure since they reflect all effective interactions in a nucleus. Within this thesis the masses of seven nuclides, namely {sup 194}Au, {sup 194}Hg, {sup 190,193,198}Tl and {sup 202,208}Pb, were determined at the Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN. The thallium region in the chart of isotopes is of special interest due to the occurrence of nuclear structure effects like low-lying isomers, level inversion, shape coexistence and deformations. These effects are investigated by applying finite-difference mass formulas, such as the two-neutron separation energies or the so-called empirical pairing gaps. The second topic addressed within the present thesis is an ultra-stable voltage source, called StaReP (Stable Reference for Penning Trap Experiments), which was developed at the Max-Planck-Institut fuer Kernphysik. It is one of the key components of the high-precision mass spectrometer PENTATRAP, containing a tower of five Penning traps. A 25-channel voltage source with a relative stability of few 10{sup -8} over a period of 10 minutes in the range of 0 to -100V is mandatory for PENTATRAP aiming for mass measurements with relative mass uncertainties of ≤ 10{sup -11}. Mass values with such a high precision allow for stringent tests of quantum electrodynamics in strong electric fields, testing Einstein's mass-energy relation E = mc{sup 2} as well as measurements of decay energies (Q-values) with applications in neutrino physics.

  7. Correlation between TL and OSL properties of CaF2:N

    International Nuclear Information System (INIS)

    Polymeris, George S.; Kitis, George; Tsirliganis, Nestor C.

    2006-01-01

    Natural CaF 2 is very well known thermoluminescent (TL) material, since it has been extensively used as a dosimeter. Its basic advantage is the exhibited high TL sensitivity. In the present work, the optically stimulated luminescence (OSL) sensitivity of this material was studied by exposing it to environmental radiation for time intervals of few hours up to a few days, and was found to be very high. By analyzing the TL glow curves and the OSL decay curves into their individual glow-peaks and components respectively, a relation between specific glow-peaks and OSL components was established. An intense thermal transfer effect occurring during optical stimulation at high temperature was observed and an explanation is offered according to existing models

  8. Glow curve characteristics of bulb type thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    Deme, S.; Feher, I.; Felszerfalvi, J.

    1993-01-01

    TL dosemeter readers are equipped usually with thermocouples connected to the heater unit. This layout can well be applied to stabilize the position of the glow curve as a function of heating-up time. Bulb type TL dosemeters do not have temperature sensors, no possibility for stabilization, which can cause an additional readout error of dose determination. For this reason, the time dependence of glow curves for bulb-type TL dosemeters was measured, and a new microprocessor controlled readout device was developed. (N.T.) 2 refs.; 2 figs

  9. Mexican gems as thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    Azorin N, J.

    1979-01-01

    The possibility of using naturally ocurring mexican gems as thermoluminescent dosimeters (TLD) was investigated. Twelve types of gems were irradiated with X and gamma rays in order to determinate their dosimetric properties. Three of these gems showed favorable thermoluminescent characteristics compared with commercial thermoluminescent dosimeters. The plots of their thermoluminescent response as a function of gamma dose are straight lines on full log paper in the dose range 10 -2 to 10 2 Gy. The energy dependence is very strong to low energies of the radiation. Their fading was found to be about 5%/yr. and they may be annealed as reused without loss in sensitivity. Therefore, these gems can be used as X and gamma radiation dosimeters. (author)

  10. CVD diamond detectors and dosimeters

    International Nuclear Information System (INIS)

    Manfredotti, C.; Fizzotti, F.; LoGiudice, A.; Paolini, C.; Oliviero, P.; Vittone, E.; Torino Univ., Torino

    2002-01-01

    Natural diamond, because of its well-known properties of tissue-equivalence, has recorded a wide spreading use in radiotherapy planning with electron linear accelerators. Artificial diamond dosimeters, as obtained by Chemical Vapour Deposition (CVD) could be capable to offer the same performances and they can be prepared in different volumes and shapes. The dosimeter sensitivity per unit volume may be easily proved to be better than standard ionization microchamber. We have prepared in our laboratory CVD diamond microchamber (diamond tips) in emispherical shape with an external diameter of 200 μm, which can be used both as X-ray beam profilometers and as microdosimeters for small field applications like stereotaxy and also for in vivo applications. These dosimeters, which are obtained on a wire substrate that could be either metallic or SiC or even graphite, display good performances also as ion or synchrotron X-rays detectors

  11. To the attention of all dosimeter users

    CERN Multimedia

    2005-01-01

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

  12. To the attention of all dosimeter users

    CERN Multimedia

    Dosimetry Service

    2005-01-01

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

  13. To the attention of all dosimeter users

    CERN Multimedia

    Dosimetry Service

    2006-01-01

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

  14. Flame-sintered ceramic exoelectron dosimeter samples

    International Nuclear Information System (INIS)

    Petel, M.; Holzapfel, G.

    1979-01-01

    New techniques for the preparation of integrating solid state dosimeters, particularly exoelectron dosimeters, have been initiated. The procedure consists in melting the powdered dosimeter materials in a hot, fast gas stream and depositing the ceramic layer. The gas stream is generated either through a chemical flame or by an electrical arc plasma. Results will be reported on the system Al 2 O 3 /stainless steel as a first step to a usable exoelectron dosimeter

  15. Spectrophotometric determination of Tl carrier in 201Tl-TlCl injection

    International Nuclear Information System (INIS)

    Gong Quansheng; Jing Lie

    1997-01-01

    A simple and sensitive method for the spectrophotometric determination of carrier content (Thallium) in 201 Tl-TlCl injection is described. Thallium (I) is oxidised to Thallium (III) by aqueous bromine, then excess bromine is removed by adding sulfosalicylic acid. In buffer solution (NH 4 Cl-NH 4 OH) at pH 11.7 with the presence of emulsifier OP, thallium (III) and cadion form a complex having an absorption maximum at 469 nm with a molar absorptivity of 1.37 x 10 4 m 2 /mol. Beer's law is obeyed in the concentration range of 0-7 μg/5 mL. The effect of impurity elements in 201 Tl-TlCl injection is examined. It is an ideal method for the analysis of radioactive solution

  16. Personnel neutron dosimeter evaluation and upgrade program

    International Nuclear Information System (INIS)

    Fix, J.J.; Brackenbush, L.W.; McDonald, J.C.; Roberson, P.L.; Holbrook, K.L.; Endres, G.W.R.; Faust, L.G.

    1983-01-01

    Evaluation of neutron dosimeters from twelve DOE laboratories involved about 2500 dosimeter irradiations at both PNL and the National Bureau of Standards (NBS) using neutrons of several energies and doses and several irradiations for good statistical analysis. The data and their analyses will be published later. The information evaluates accuracy, precision, lower dose detection, and energy response of dosimeters

  17. Dosimeter charging and/or reading apparatus

    International Nuclear Information System (INIS)

    Fine, L.T.; Jackson, T.P.

    1980-01-01

    A device is disclosed for charging and/or reading a capacitor associated with an electrometer incorporated in a radiation dosimeter for the purpose of initializing or ''zeroing'', the dosimeter at the commencement of a radiation measurement cycle or reading it at any time thereafter. The dosimeter electrometer has a movable electrode the position of which is indicative of the charge remaining on the dosimeter capacitor and in turn the amount of radiation incident on the dosimeter since it was zeroed. The charging device also includes means for discharging, immediately upon conclusion of the dosimeter capacitor charging operation, stray capacitance inherent in the dosimeter by reason of its mechanical construction. The charge on the stray capacitance, if not discharged at the conclusion of the dosimeter capacitor charging operation, leaks off during the measurement cycle, introducing measurement errors. A light source and suitable switch means are provided for automatically illuminating the movable electrode of the dosimeter electrometer as an incident to charging the dosimeter capacitor to facilitate reading the initial, or ''zero'', position of the movable electrometer electrode after the dosimeter capacitor has been charged and the stray capacitance discharged. Also included is a manually actuatable switch means, which is operable independently of the aforementioned automatic switch means, to energize the lamp and facilitate reading of the dosimeter without charging

  18. Solid-state personal dosimeter using dose conversion algorithm

    International Nuclear Information System (INIS)

    Lee, B.J.; Lee, Wanno; Cho, Gyuseong; Chang, S.Y.; Rho, S.R.

    2003-01-01

    Solid-state personal dosimeters using semiconductor detectors have been widely used because of their simplicity and real time operation. In this paper, a personal dosimeter based on a silicon PIN photodiode has been optimally designed by the Monte Carlo method and also developed. For performance test, the developed dosimeter was irradiated within the energy range between 50 keV and 1.25 MeV, the exposure dose rate between 3 mR/h and 25 R/h. The thickness of 0.2 mm Cu and 1.0 mm Al was selected as an optimal filter by simulation results. For minimizing the non-linear sensitivity on energy, dose conversion algorithm was presented, which was able to consider pulse number as well as pulse amplitude related to absorbed energies. The sensitivities of dosimeters developed by the proposed algorithm and the conventional method were compared and analyzed in detail. When dose conversion algorithm was used, the linearity of sensitivity was better about 38%. This dosimeter will be used for above 65 keV within the relative response of ±10% to 137 Cs

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  20. Cell-phone interference with pocket dosimeters

    International Nuclear Information System (INIS)

    Djajaputra, David; Nehru, Ramasamy; Bruch, Philip M; Ayyangar, Komanduri M; Raman, Natarajan V; Enke, Charles A

    2005-01-01

    Accurate reporting of personal dose is required by regulation for hospital personnel that work with radioactive material. Pocket dosimeters are commonly used for monitoring this personal dose. We show that operating a cell phone in the vicinity of a pocket dosimeter can introduce large and erroneous readings of the dosimeter. This note reports a systematic study of this electromagnetic interference. We found that simple practical measures are enough to mitigate this problem, such as increasing the distance between the cell phone and the dosimeter or shielding the dosimeter, while maintaining its sensitivity to ionizing radiation, by placing it inside a common anti-static bag. (note)

  1. Cell-phone interference with pocket dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Djajaputra, David; Nehru, Ramasamy; Bruch, Philip M; Ayyangar, Komanduri M; Raman, Natarajan V; Enke, Charles A [Department of Radiation Oncology, University of Nebraska Medical Center, 987521 Nebraska Medical Center, Omaha, NE 68198-7521 (United States)

    2005-05-07

    Accurate reporting of personal dose is required by regulation for hospital personnel that work with radioactive material. Pocket dosimeters are commonly used for monitoring this personal dose. We show that operating a cell phone in the vicinity of a pocket dosimeter can introduce large and erroneous readings of the dosimeter. This note reports a systematic study of this electromagnetic interference. We found that simple practical measures are enough to mitigate this problem, such as increasing the distance between the cell phone and the dosimeter or shielding the dosimeter, while maintaining its sensitivity to ionizing radiation, by placing it inside a common anti-static bag. (note)

  2. Acceptance Testing of Thermoluminescent Dosimeter Holders.

    Science.gov (United States)

    Romanyukha, Alexander; Grypp, Matthew D; Sharp, Thad J; DiRito, John N; Nelson, Martin E; Mavrogianis, Stanley T; Torres, Jeancarlo; Benevides, Luis A

    2018-05-01

    The U.S. Navy uses the Harshaw 8840/8841 dosimetric (DT-702/PD) system, which employs LiF:Mg,Cu,P thermoluminescent dosimeters (TLDs), developed and produced by Thermo Fisher Scientific (TFS). The dosimeter consists of four LiF:Mg,Cu,P elements, mounted in Teflon® on an aluminum card and placed in a plastic holder. The holder contains a unique filter for each chip made of copper, acrylonitrile butadiene styrene (ABS), Mylar®, and tin. For accredited dosimetry labs, the ISO/IEC 17025:2005(E) requires an acceptance procedure for all new equipment. The Naval Dosimetry Center (NDC) has developed and tested a new non-destructive procedure, which enables the verification and the evaluation of embedded filters in the holders. Testing is based on attenuation measurements of low-energy radiation transmitted through each filter in a representative sample group of holders to verify that the correct filter type and thickness are present. The measured response ratios are then compared with the expected response ratios. In addition, each element's measured response is compared to the mean response of the group. The test was designed and tested to identify significant nonconformities, such as missing copper or tin filters, double copper or double tin filters, or other nonconformities that may impact TLD response ratios. During the implementation of the developed procedure, testing revealed a holder with a double copper filter. To complete the evaluation, the impact of the nonconformities on proficiency testing was examined. The evaluation revealed failures in proficiency testing categories III and IV when these dosimeters were irradiated to high-energy betas.

  3. Improved sample holders for the PMMA dosimeters

    International Nuclear Information System (INIS)

    Kobayashi, Toshikazu; Sone, Koji; Iso, Katsuaki

    1994-01-01

    PMMA dosimeters are widely used for high dose dosimetry. Dose is determined by measuring the change in optical density of the irradiated PMMA dosimeter element. Measurement precision depends on the mounting method of a dosimeter element in the sample room of a spectrophotometer. We tried to prepare three types of holders, (holders A, B and C in Figs. 1-3), according to the shape of PMMA dosimeter elements. We measured optical density of the irradiated PMMA dosimeter elements by using the three types of holders. It is revealed that the holder of the type A gives more precise results for the Red 4034 or Gammachrome YR dosimeter than that of the type B. The measurements with a spectrophotometer using the type C holder gives better results for the Red acrylic dosimeter than the case of the measurements by the exclusive reader. (author)

  4. Design, construction and characterization of a dosimeter for neutron radiation

    International Nuclear Information System (INIS)

    Souto, Eduardo de Brito

    2007-01-01

    An individual dosimeter for neutron-gamma mixed field dosimetry was design and developed aiming monitoring the increasing number of workers potentially exposed to neutrons. The proposed dosimeter was characterized to an Americium-Beryllium source spectrum and dose range of radiation protection interest (up to 20 mSv). Thermoluminescent albedo dosimetry and nuclear tracks dosimetry, traditional techniques found in the international literature, with materials of low cost and national production, were used. A commercial polycarbonate, named SS-1, was characterized for solid state tack detector application. The chemical etching parameters and the methodology of detectors evaluation were determined. The response of TLD-600, TLD-700 and SS-1 were studied and algorithms for dose calculation of neutron and gamma radiation of Americium- Beryllium sources were proposed. The ratio between thermal, albedo and fast neutrons responses, allows analyzing the spectrum to which the dosimeter was submitted and correcting the track detector response to variations in the radiation incidence angle. The new dosimeter is fully characterized, having sufficient performance to be applied as neutron dosimeter in Brazil. (author)

  5. Personnel neutron dosimeter for use in a plutonium processing plant

    International Nuclear Information System (INIS)

    Brunskill, R.T.; Hwang, F.S.W.

    1978-01-01

    A thermoluminesence dosimeter for personnel neutron dose measurement, which is based on the albedo principle, has been developed at Windscale works. The dosimeter has been calibrated against a 238 Pu/Be neutron source using different degrees of moderation and against a variety of neutron spectra prevailing in different areas of the Plutonium Finishing Plant. The dosimeter consists of two identical parts in which the sensitive elements are graphite discs which have thermoluminescent crystals sealed to the plane faces with a high temperature resin. The graphite discs are supported in teflon washers which fit into a body of tufnol. A circular insert of boronated polythene in each tufnol body provides a thermal neutron absorber for the sensitive element in the other half of the dosimeter. Natural lithium borate was used as the neutron sensitive phosphor and a lithium borate made from isotopes 7 Li (99.9%) and 11 B (99.2%) as the neutron insensitive materials. Neutron-sensitive lithium borate is sealed to one face of each disc and the neutron-insensitive material to the opposite face. The dosimeter is so assembled that the neutron-sensitive faces both lie in the central plane. The design is such that one neutron sensitive face responds to the incident flux of neutron only while the other responds to the albedo flux

  6. Optimizing the sensitivity and radiological properties of the PRESAGE® dosimeter using metal compounds

    International Nuclear Information System (INIS)

    Alqathami, Mamdooh; Blencowe, Anton; Qiao, Greg; Adamovics, John; Geso, Moshi

    2012-01-01

    The aim of this study is to investigate the radiation-modifying effects of incorporating commercially available bismuth-, tin- and zinc-based compounds in the composition of the PRESAGE ® dosimeter, and the feasibility of employing such compounds for radiation dose enhancement. Furthermore, we demonstrate that metal compounds can be included in the formulation to yield water-equivalent PRESAGE ® dosimeters with enhanced dose response. Various concentrations of the metal compounds were added to a newly developed PRESAGE ® formulation and the resulting dosimeters were irradiated with 100 kV and 6 MV photon beams. A comparison between sensitivity and radiological properties of the PRESAGE ® dosimeters with and without the addition of metal compounds was carried out. Optical density changes of the dosimeters before and after irradiation were measured using a spectrophotometer. In general, when metal compounds were incorporated in the composition of the PRESAGE ® dosimeter, the sensitivity of the dosimeters to radiation dose increased depending on the type and concentration of the metal compound, with the bismuth compound showing the highest dose enhancement factor. In addition, these metal compounds were also shown to improve the retention of the post-response absorption value of the PRESAGE ® dosimeter over a period of 2 weeks. Thus, incorporating 1–3 mM (ca. 0.2 wt%) of any of the three investigated metal compounds in the composition of the PRESAGE ® dosimeter is found to be an efficient way to enhance the sensitivity of the dosimeter to radiation dose and stabilize its post-response for longer times. Furthermore, the addition of small amounts of the metal compounds also accelerates the polymerization of the PRESAGE ® dosimeter precursors, significantly reducing the fabrication time. Finally, a novel water-equivalent PRESAGE ® dosimeter formula optimized with metal compounds is proposed for clinical use in both kilovoltage and megavoltage radiotherapy

  7. Remote TL and OSL for asteroid and meteorite study

    International Nuclear Information System (INIS)

    Takaki, Shunji; Ikeya, Motoji; Yamanaka, Chihiro

    1997-01-01

    Thermoluminescence (TL) and optically stimulated luminescence (OSL) of the Allende meteorite have been studied using infrared CO 2 laser light as a heat source and He-Ne laser light to excite the material, respectively from a long distance. New techniques of remote TL (R-TL) and remote OSL (R-OSL) have been developed for future remote dating from a long distance in a planetary survey. The upper limits of the distance for R-TL and R-OSL were estimated using the laboratory TL signal of the meteorite peaking at 320 o C: about 400 photons s -1 for the R-TL and 60 photons s -1 for R-OSL at a distance of 1 km using a laser beam with the divergence of 0.1 mrad at powers of 100 and 1 W, respectively. An age limit of 10 5 or 10 6 years due to the signal saturation and the objects heterogeneity, as expected from previous studies, may make the asteroid survey difficult but would still help to investigate the surface activities of icy planets and satellites in outer planet worlds. (author)

  8. Phototransfered thermoluminescence for dose reassessment in LiF:mg,ti , LiF: mg,Cu,p TL detectors

    International Nuclear Information System (INIS)

    Rodriguez Otazo, M.; Baly, L.

    2001-01-01

    Phototransfered Thermoluminescence (PTTL) from LiF:Mg,Ti (TLD-100) and LiF: Mg,Cu,P (GR-200) was studied at different conditions using different sources of UV light for dose reassessment purposes. The TL dosimeters were irradiated with 137Cs in the range 2 mGy to 100 mGy. The convenience of using PTTL for dose reassessment was analyzed

  9. Operation of Personal Electronic Dosimeters at NRCN

    International Nuclear Information System (INIS)

    Weinstein, M.; Abraham, A.; Tshuva, A.; German, U.

    2004-01-01

    In the recent years, electronic personal dosimeters (EPD's) are increasingly being used at NRCN, replacing the old direct reading dosimeters that are still widely used. The most significant advantage of the new dosimeters is the real time alarm in a radiation field exceeding a pre-determined threshold. The EPD dosimeters are more precise and can measure γ, β and x rays of a wide range of energies. In addition, the electronic dosimeters collects and stores the reading at a fixed pattern (every 10 seconds) and keeps the data until it is downloaded from the dosimeter. This feature gives the ability to build a personal time-dependent exposure report for each worker who carries this device and to analyze, identify and measure the exact dose, time and duration of any exposure event he was involved in. Designing and building a personal electronic dosimeter became possible as a result of the massive technological improvements of semi conductor detectors and the minimization processes of microprocessors and low energy electronic devices. The main purpose for personal electronic dosimeters was to monitor on-line doses for radiation workers.A special reader device enables to download data and upload operational settings of the dosimeters. By means of this communication channel, one can save the data acquired by the dosimeter, clear the dosimeter memory and set the dosimeter operational parameters. There are two possible working patterns. The first is to read and set all the dosimeters at a central point, normally a dosimetry laboratory (single reader) and the second and more expensive one, is to build a network of readers covering the plant for obtaining on-line communication

  10. Electret dosimeter utilizing gas multiplication

    International Nuclear Information System (INIS)

    Ikeya, M.; Miki, T.

    1980-01-01

    It was found that the high electric field around the surface of an electret leads to cascade multiplication of the ionization process in a surrounding gas. Very sensitive charge decay constants of the order of 1mrad, were obtained for electrets composed of polyvinyliden fluoride or teflon polymers. The reduced charge is stable and can be utilized in personnel dosimetry. A simple pocket chamber dosimeter is described consisting of a small speaker or buzzer, a cylindrical chamber filled with air, argon or other gases, a polymer thermoelectret foil and an electrode. The sonic vibration of the foil induces an alternating charge on the electrode which is amplified and detected. The feasibility of this dosimeter and its shock and vibration resistance have been demonstrated. (author)

  11. Tl Cuprate Superconductors Studied by XPS

    Energy Technology Data Exchange (ETDEWEB)

    Vasquez, R. P. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099 (United States); Siegal, M. P. [Sandia National Laboratories, Albuquerque, NM 87185-1421 (United States); Overmyer, D. L. [Sandia National Laboratories, Albuquerque, NM 87185-1421 (United States); Ren, Z. F. [Department of Chemistry, State University of New York, Buffalo, NY 14260-3000 (United States); Lao, J. Y. [Department of Chemistry, State University of New York, Buffalo, NY 14260-3000 (United States); Wang, J. H. [Department of Chemistry, State University of New York, Buffalo, NY 14260-3000 (United States)

    1999-07-01

    XPS measurements on epitaxial thin films of the Tl cuprate superconductors Tl2Ba2CaCu2O8, Tl2Ba2Ca2Cu3O10, and Tl0.78Bi0.22Ba0.4Sr1.6Ca2Cu3O9-{delta} are presented. These data, together with previous measurements in this lab on Tl2Ba2CuO6-{delta} and TlBa2CaCu2O7-{delta}, comprise a comprehensive data set for comparison of Tl cuprates in which the number of Tl-O and Cu-O layers, and hence the chemical and electronic properties, vary. (c) 2000 American Vacuum Society.

  12. Tl Cuprate Superconductors Studied by XPS

    International Nuclear Information System (INIS)

    Vasquez, R. P.; Siegal, M. P.; Overmyer, D. L.; Ren, Z. F.; Lao, J. Y.; Wang, J. H.

    1999-01-01

    XPS measurements on epitaxial thin films of the Tl cuprate superconductors Tl2Ba2CaCu2O8, Tl2Ba2Ca2Cu3O10, and Tl0.78Bi0.22Ba0.4Sr1.6Ca2Cu3O9-δ are presented. These data, together with previous measurements in this lab on Tl2Ba2CuO6-δ and TlBa2CaCu2O7-δ, comprise a comprehensive data set for comparison of Tl cuprates in which the number of Tl-O and Cu-O layers, and hence the chemical and electronic properties, vary. (c) 2000 American Vacuum Society

  13. RADIATION DOSIMETER AND DOSIMETRIC METHODS

    Science.gov (United States)

    Taplin, G.V.

    1958-10-28

    The determination of ionizing radiation by means of single fluid phase chemical dosimeters of the colorimetric type is presented. A single fluid composition is used consisting of a chlorinated hydrocarbon, an acidimetric dye, a normalizer and water. Suitable chlorinated hydrocarbons are carbon tetrachloride, chloroform, trichloroethylene, trichlorethane, ethylene dichioride and tetracbloroethylene. Suitable acidimetric indicator dyes are phenol red, bromcresol purple, and creosol red. Suitable normallzers are resorcinol, geraniol, meta cresol, alpha -tocopberol, and alpha -naphthol.

  14. Approving of personal dosimeter services

    International Nuclear Information System (INIS)

    Bergman, K.; Malmqvist, L.

    2001-09-01

    The Swedish regulation SSI FS 98:5 requires that radiological workers of category A use dosemeters from an approved personal dosimetry service. The regulation also includes certain specific dosimeter requirements, which are based on those presented in the Technical Recommendations by the European Commission (Report EUR 14852 EN, 1994). All services have been tested for their ability to determine Hp(10) and some of them to determine Hp(0.07) at one radiation quality. The test was performed in the interval 0.2 mSv to 100 mSv at three different dose equivalents unknown to the system owner. The 11 services operating in Sweden at the moment use 5 different types of dosimeters. The five unique systems have been tested regarding the angular and energy dependence of the response of the dosimeters. The dosimeters were irradiated to a personal dose equivalent of about 1 mSv at three photon energies and at four angles (0, 20, 40 and 60 deg. resp. ) both vertically and horizontally rotated. Only 2 of the services determine Hp(0.07) for beta and gamma radiation and were tested for this quantity. The test results for Hp(10) are all except two within the trumpet curve. For the unique systems it is shown that the uncertainty related to angular response at a specified energy is within the required ±40 % except for the lowest X-ray quality at 40 kV. The response is more dependent on photon energy than on the direction of the photon radiation and the choice of radiation quality for the calibration is of great importance for the system performance

  15. Radiation sensitive polymer gel dosimeters

    International Nuclear Information System (INIS)

    Lepage, M.; Back, S.A.J.; Baldock, C.; Whittaker, A.K.; Rintoul, L.

    2000-01-01

    Full text: Radiation sensitive gels are studied for their potential to retain a permanent 3D dose distribution for applications in radiotherapy. Co-monomers dissolved in a tissue-equivalent hydrogel undergo a polymerization reaction upon absorption of ionizing radiation. The polymer formed influences the local spin-spin relaxation time (T 2 ) of the dosimeter that can be determined using magnetic resonance imaging (MRI). The relationship between T2 and the absorbed dose was studied for different initial chemical compositions. The aim was to find a model linking the changes in T 2 with absorbed dose to the initial composition of the dosimeter. It is believed this will help designing new gel dosimeters having desired properties to minimize the uncertainty in the determination of the dose distribution. 1 H, 13 C nuclear magnetic resonance spectroscopy and FT-Raman spectroscopy were used to quantify the amount of monomers still remaining after the absorption of a given dose of radiation. This data is used to model the changes of T2 as a function of the absorbed dose. A model of fast exchange of magnetization between three proton pools was used, where the fraction of protons (f x H ) in the x th pool is obtained from the chemical composition of the dosimeter and the apparent T2 of each pool is determined for a given composition. Initially, the protons are contained in two pools; a mobile (mob), which contains the water protons and the monomers protons, and a gelatin (gela) proton pool. The mobile pool is partially depleted as polymer is formed, the protons are transferred into the polymer (pol) pool. In the figure, the experimental data along with the calculated values are plotted for three different monomer concentrations, with the gelatin concentration fixed. The model is seen to provide a good fit to the experimental data

  16. Radiation accident dosimetry: TL properties of mobile phone screen glass

    International Nuclear Information System (INIS)

    Bassinet, C.; Pirault, N.; Baumann, M.; Clairand, I.

    2014-01-01

    Mobile phones are carried by a large part of the population and previous studies have shown that they may be able to function as individual fortuitous dosimeters in case of radiological accident. This study deals with thermoluminescence (TL) properties of mobile phone screen glass. The presence of a significant background signal which partially overlaps with the radiation-induced signal is a serious issue for dose reconstruction. A mechanical method to reduce this signal using a diamond grinding bit is presented. An over-response at low energy (∼50 keV) is observed for two investigated glasses. The results of a dose recovery test using a single-aliquot regenerative-dose (SAR) procedure are discussed. - Highlights: • Mobile phone screen glass is a promising material for retrospective dosimetry. • The TL non-radiation induced background signal can be significantly reduced by a mechanical method. • A dose recovery test using an SAR procedure was successfully carried out for the investigated glass

  17. The dosimeter personal use in controlled area

    International Nuclear Information System (INIS)

    Costa, R. F.

    2015-01-01

    The discovery of X-rays revolutionized medicine because it allowed a patient to be examined internally with no surgery. But also caused damage to health professionals and patients due, its oxidizing action. In the beginning of its discovery, many doctors were exposed and exposed beams to their patients for long periods of time, therefore, they developed diseases caused by radiation and the medical community realized that something was wrong. Then created a radiological protection commission to regulate its use in humans and so limit your exposure. Today we know that many companies still did not fit the standards of radiation protection. So we evaluate the technical professionals in radiology regarding the correct use of personal dosimeter, through a descriptive study with a quantitative approach, we used the information collection technique based on a questionnaire developed for this purpose which was delivered and collected personally. From this survey, we sought to assess the knowledge of the basic guidelines of radiological protection. He concluded that the majority of respondents know the rules of use of the personal dosimeter, but do not use it properly, due mainly to lack of supervision by the company, overwork and neglect. (author)

  18. DEPRON dosimeter for ``Lomonosov'' satellite

    Science.gov (United States)

    Brilkov, Ivan; Vedenkin, Nikolay; Panasyuk, Mikhail; Amelyushkin, Aleksandr; Petrov, Vasily; Nechayev, Oleg; Benghin, Victor

    It is commonly known, that cosmic radiation generates negative impact on the human body during space flight. The structure of the radiation fields in the near-Earth space was studied during intensive research of recent decades. Huge number of dosimetry studies was conducted on manned and unmanned space vehicles in order to solve the problem of radiation safety humans during space flights. It should be noted that most of the measurements was made onboard the spacecrafts, flying along the orbits with inclination of up to 51.6 degrees. Due to the prospect of manned missions at the orbits with larger inclination it seems advisable to conduct preliminary detailed dosimetry measurements at high-altitude orbit, for which the "Lomonosov" satellite provides good opportunities. We chose a method of cosmic radiation dosimetry based on semiconductor detectors. Proposed in the late 70's this method is widely used onboard spacecraft, including full-time radiation monitoring onboard the ISS. Recently it has been improved, providing an opportunity to register not only the absorbed dose of charged particles radiation, but also range of their ionization losses. It allowed assessment of equivalent dose. Appropriate procedure based on using of a telescope consisting of two semiconductor detectors provided a basis of the developed unit. It should be noted that not only the charged particles contribute significantly in the equivalent dose, but also neutrons do. Semiconductor detectors have low sensitivity to neutron radiation and are not sufficient for detecting the expected flux of neutrons. It was therefore decided to add thermal neutrons counter to the developed device in order to provide an opportunity of estimation of neutron flux variations along the satellite trajectory. A gas-discharge counter SI-13N, operated in a mode of corona discharge was chosen as a neutron detector. This method of neutron detection is well-proven and used many times in SINP MSU experiments. Thus, the

  19. 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)

  20. Assessment of Siemens plessey electronic personal dosimeter

    International Nuclear Information System (INIS)

    Hirning, C.R.; Lopez, S.; Yuen, P.S.

    1994-01-01

    This report presents the results of a laboratory assessment of the performance of a new type of personal dosimeter. The Electronic Personal Dosimeter, or EPD, was developed jointly by the National Radiological Protection Board and Siemens Plessey Controls Limited, both of the United Kingdom. Twenty pre-production units of the EPD and a reader were purchased by Ontario Hydro for the assessment. The tests were conducted jointly by Ontario Hydro's Health and Safety Division and AECL Research's Chalk River Laboratories (CRL), with funding from the Candu Owner's Group. A total of 26 tests were conducted, divided between Ontario Hydro and AECL. The test results were compared with the relevant requirements of three standards. In general, the performance of the EPD was found to be quite acceptable. It met most of the relevant requirements of the three standards and most of the design specifications. However, the following deficiencies were found: slow response time; sensitivity to high-frequency EMF; poor resistance to dropping; and an alarm that is not loud enough. In addition, the response of the EPD to low-energy beta rays may be too low for some applications. There were serious problems with the reliability of operation of the pre production EPDs used in these tests. 9 refs., 34 tabs., 20 figs

  1. Assessment of Siemens plessey electronic personal dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Hirning, C R; Lopez, S [Ontario Hydro, Toronto, ON (Canada); Yuen, P S [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.

    1994-01-01

    This report presents the results of a laboratory assessment of the performance of a new type of personal dosimeter. The Electronic Personal Dosimeter, or EPD, was developed jointly by the National Radiological Protection Board and Siemens Plessey Controls Limited, both of the United Kingdom. Twenty pre-production units of the EPD and a reader were purchased by Ontario Hydro for the assessment. The tests were conducted jointly by Ontario Hydro`s Health and Safety Division and AECL Research`s Chalk River Laboratories (CRL), with funding from the Candu Owner`s Group. A total of 26 tests were conducted, divided between Ontario Hydro and AECL. The test results were compared with the relevant requirements of three standards. In general, the performance of the EPD was found to be quite acceptable. It met most of the relevant requirements of the three standards and most of the design specifications. However, the following deficiencies were found: slow response time; sensitivity to high-frequency EMF; poor resistance to dropping; and an alarm that is not loud enough. In addition, the response of the EPD to low-energy beta rays may be too low for some applications. There were serious problems with the reliability of operation of the pre production EPDs used in these tests. 9 refs., 34 tabs., 20 figs.

  2. Measurements of environmental gamma-ray spectra using a multi-element TL dosemeter

    International Nuclear Information System (INIS)

    Furuta, Sadaaki; Boetter-Jensen, L.; Nielsen, S.P.

    1986-12-01

    A method to estimate the energy distribution and dose of environmental gamma radiation was developed using a multielement TL dosemeter. Experimentally obtained energy responses from a multi-element TL dosemeter with different kinds of filters were used to calculate the energy distribution and related dose by the SAND-II computer code. The code was originally developed to estimate the neutron flux using a multiple foil activation method. Measurements were made at several locations with the multi-element TL dosemeter and comparisons were made with results from a NaI(Tl) scintillation detector and a high-pressure ionization chamber. (author)

  3. Angular response characterization of the Martin Marietta Energy Systems, Inc., personnel dosimeter

    International Nuclear Information System (INIS)

    Ahmed, A.B.; McMahan, K.L.; Colwell, D.S.

    1993-08-01

    An evaluation of the Martin Marietta Energy Systems, Inc., personnel dosimeter to radiation incident from non-perpendicular angles was carried out to meet the Department of Energy Laboratory Accreditation Program (DOELAP) requirements. Dosimeters were exposed to six different radiation sources. For each source, dosimeters were rotated about their horizontal and vertical axes at seven different angles each. Raw readings were processed through the dose calculation algorithm used for routine personnel dosimetry to determine dose equivalent values. Dose equivalent responses relative to zero degree incident angle were found to be within ± 20% for M150, K-59 and 137 Cs photons when the incident angle was 60 degree or less. For low-energy photon irradiations (M30 and K-16), responses for angles other than perpendicular incidence are generally unpredictable. Reasons include: (1) failure of dose calculation algorithm to identify the radiation field correctly due to unusual element ratios; and (2) at extreme angles (± 85 degree), the dosimeter design (in relation to the irradiation geometry) becomes the limiting factor in producing reproducible results. Response to 204 Tl beta particles decreases rapidly with increasing angle of incidence

  4. Water equivalence of NIPAM based polymer gel dosimeters with enhanced sensitivity for x-ray CT

    Science.gov (United States)

    Gorjiara, Tina; Hill, Robin; Bosi, Stephen; Kuncic, Zdenka; Baldock, Clive

    2013-10-01

    Two new formulations of N-isopropylacrylamide (NIPAM) based three dimensional (3D) gel dosimeters have recently been developed with improved sensitivity to x-ray CT readout, one without any co-solvent and the other one with isopropanol co-solvent. The water equivalence of the NIPAM gel dosimeters was investigated using different methods to calculate their radiological properties including: density, electron density, number of electrons per grams, effective atomic number, photon interaction probabilities, mass attenuation and energy absorption coefficients, electron collisional, radiative and total mass stopping powers and electron mass scattering power. Monte Carlo modelling was also used to compare the dose response of these gel dosimeters with water for kilovoltage and megavoltage x-ray beams and for megavoltage electron beams. We found that the density and electron density of the co-solvent free gel dosimeter are more water equivalent with less than a 2.6% difference compared to a 5.7% difference for the isopropanol gel dosimeter. Both the co-solvent free and isopropanol solvent gel dosimeters have lower effective atomic numbers than water, differing by 2.2% and 6.5%, respectively. As a result, their photoelectric absorption interaction probabilities are up to 6% and 19% different from water, respectively. Compton scattering and pair production interaction probabilities of NIPAM gel with isopropanol differ by up to 10% from water while for the co-solvent free gel, the differences are 3%. Mass attenuation and energy absorption coefficients of the co-solvent free gel dosimeter and the isopropanol gel dosimeter are up to 7% and 19% lower than water, respectively. Collisional and total mass stopping powers of both gel dosimeters differ by less than 2% from those of water. The dose response of the co-solvent free gel dosimeter is water equivalent (with x-ray beams over the energy range 180 keV-18 MV, both gel dosimeters have less than 2% discrepancy with water. For

  5. SCOPE-mTL: A non-invasive tool for identifying and lateralizing mesial temporal lobe seizures prior to scalp EEG ictal onset.

    Science.gov (United States)

    Lam, Alice D; Maus, Douglas; Zafar, Sahar F; Cole, Andrew J; Cash, Sydney S

    2017-09-01

    In mesial temporal lobe (mTL) epilepsy, seizure onset can precede the appearance of a scalp EEG ictal pattern by many seconds. The ability to identify this early, occult mTL seizure activity could improve lateralization and localization of mTL seizures on scalp EEG. Using scalp EEG spectral features and machine learning approaches on a dataset of combined scalp EEG and foramen ovale electrode recordings in patients with mTL epilepsy, we developed an algorithm, SCOPE-mTL, to detect and lateralize early, occult mTL seizure activity, prior to the appearance of a scalp EEG ictal pattern. Using SCOPE-mTL, 73% of seizures with occult mTL onset were identified as such, and no seizures that lacked an occult mTL onset were identified as having one. Predicted mTL seizure onset times were highly correlated with actual mTL seizure onset times (r=0.69). 50% of seizures with early mTL onset were lateralizable prior to scalp ictal onset, with 94% accuracy. SCOPE-mTL can identify and lateralize mTL seizures prior to scalp EEG ictal onset, with high sensitivity, specificity, and accuracy. Quantitative analysis of scalp EEG can provide important information about mTL seizures, even in the absence of a visible scalp EEG ictal correlate. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  6. Water equivalence of NIPAM based polymer gel dosimeters with enhanced sensitivity for x-ray CT

    International Nuclear Information System (INIS)

    Gorjiara, Tina; Hill, Robin; Bosi, Stephen; Kuncic, Zdenka; Baldock, Clive

    2013-01-01

    Two new formulations of N-isopropylacrylamide (NIPAM) based three dimensional (3D) gel dosimeters have recently been developed with improved sensitivity to x-ray CT readout, one without any co-solvent and the other one with isopropanol co-solvent. The water equivalence of the NIPAM gel dosimeters was investigated using different methods to calculate their radiological properties including: density, electron density, number of electrons per grams, effective atomic number, photon interaction probabilities, mass attenuation and energy absorption coefficients, electron collisional, radiative and total mass stopping powers and electron mass scattering power. Monte Carlo modelling was also used to compare the dose response of these gel dosimeters with water for kilovoltage and megavoltage x-ray beams and for megavoltage electron beams. We found that the density and electron density of the co-solvent free gel dosimeter are more water equivalent with less than a 2.6% difference compared to a 5.7% difference for the isopropanol gel dosimeter. Both the co-solvent free and isopropanol solvent gel dosimeters have lower effective atomic numbers than water, differing by 2.2% and 6.5%, respectively. As a result, their photoelectric absorption interaction probabilities are up to 6% and 19% different from water, respectively. Compton scattering and pair production interaction probabilities of NIPAM gel with isopropanol differ by up to 10% from water while for the co-solvent free gel, the differences are 3%. Mass attenuation and energy absorption coefficients of the co-solvent free gel dosimeter and the isopropanol gel dosimeter are up to 7% and 19% lower than water, respectively. Collisional and total mass stopping powers of both gel dosimeters differ by less than 2% from those of water. The dose response of the co-solvent free gel dosimeter is water equivalent (with 100 keV, correction factor is required for the gels. • For MV electron, correction factor needed for the gels to

  7. Luminescence properties of common salt (NaCl available in Nigeria for use as accident dosimeter in radiological emergency situation

    Directory of Open Access Journals (Sweden)

    Janet Ayobami Ademola

    2017-04-01

    Full Text Available In the event of a radiological accident or attack, it is important to assess and quantify radiation dose to the population. This could be done using materials in the vicinity that are sensitive to ionizing radiation. Common salt (NaCl is known to be a sensitive thermoluminescence (TL phosphor. Luminescence properties of common salt (NaCl used in Nigeria were investigated using an automated luminescence reader Risø TL/OSL-DA-15, with attention focused more on the Optically Stimulated Luminescence (OSL. Strong radiation-induced TL and OSL signals were observed. The TL peaks occurred at about 100 °C, 240 °C and 280 °C. The dose response of both the TL and OSL signals showed a linear relationship. From the OSL pulse anneal curve with TL curve, a preheat temperature of 190 °C for 10 s was found adequate for the OSL measurements. There was no significant difference in the OSL decay for stimulation temperatures of 100 and 120 °C. Fading experiment over a storage period of 14 days showed about 13 and 3% decrease in the OSL signal of sample 1 and sample 2, respectively. The ratios of measured to given dose for dose recovery test were within ±19% of unity. Within the limit of error the samples could be used as a complementary emergency dosimeter in radiological accident situation.

  8. Temperature dependence of gafchromic MD-55 dosimeter

    International Nuclear Information System (INIS)

    Klassen, Norman V.; Zwan, Len van der; Cygler, Joanna

    1997-01-01

    Objective: Gafchromic MD-55 is a fairly new, thin film dosimeter that develops a blue color (λ max = 676 nm) when irradiated with ionizing radiation. The increase in absorbance is nearly proportional to the absorbed dose. MD-55 can be used for high precision dosimetry if care is taken to assure reproducible film orientation in the spectrophotometer as well as temperature control during both irradiation and reading. In order to achieve the maximum sensitivity of this dosimeter the readings of the optical density should be taken at λ max . It was reported for another type of Gafchromic film (DM-1260), that both λ max and ε max decrease with an increase in the temperature of the spectrophotometer. The purpose of this study was to characterize the reading temperature dependence of the new type of Gafchromic film available on the market and to find optimal conditions for using it for high precision dosimetry. Materials and Methods: Irradiations were carried out using 60 Co gamma rays from an Eldorado irradiator. The dosimeters were sandwiched in a lucite phantom with 4.4 mm build-up and irradiated in the center of a 10 cm x 10 cm field at 1 meter from the source. The temperature during irradiations was 22 deg. C. The dose rate was about 0.68 Gy/min. Measurements of optical density were made using a Cary 210 spectrophotometer. A bandpass of 3.5 nm was used. The temperature of the baseplate of the sample holder was regulated to +/-0.05 deg. C and measured by a probe lying on the baseplate. In all cases, values of OD were only recorded after they had come to a constant value, which was reached within 5 minutes of inserting the dosimeter into the sample chamber of the spectrophotometer. Results: The temperature dependence of the OD at 676 nm was measured in 2 studies using 6 dosimeters that had received 0, 1.0, 3.5, 6.2, 14.5 Gy. Readings were taken at 7 temperatures between 18.8 and 28.1 deg. C. By returning to the initial temperature several hours later, it was found

  9. Investigation of thermoluminescence properties of mobile phone screen displays as dosimeters for accidental dosimetry

    Science.gov (United States)

    Mrozik, Anna; Marczewska, B.; Bilski, P.; Kłosowski, M.

    2014-11-01

    The rapid assessment of the radiation dose after unexpected exposure is a task of accidental dosimetry. In case of a radiological accident glasses originating from mobile phone screens, placed usually near the human body, could be used as emergency thermoluminescent (TL) personal dosimeters. The time between irradiation and TL readout is crucial and therefore preparation of the mobile phone screens and their readout conditions should be optimized. The influence of the samples etching, bleaching and selection of the optical filters based on measurement of the emission spectrum of irradiated glass samples during heating for different types of mobile phones were the subjects of our investigation. Obtained results showed that glasses extracted from different brands of mobile phones have different dosimetric properties but all of them give a luminescent signal which can be used to calculate the dose.

  10. Benchmarking NaI(Tl) Electron Energy Resolution Measurements

    International Nuclear Information System (INIS)

    Mengesha, Wondwosen; Valentine, J D.

    2002-01-01

    A technique for validating electron energy resolution results measured using the modified Compton coincidence technique (MCCT) has been developed. This technique relies on comparing measured gamma-ray energy resolution with calculated values that were determined using the measured electron energy resolution results. These gamma-ray energy resolution calculations were based on Monte Carlo photon transport simulations, the measured NaI(Tl) electron response, a simplified cascade sequence, and the measured electron energy resolution results. To demonstrate this technique, MCCT-measured NaI(Tl) electron energy resolution results were used along with measured gamma-ray energy resolution results from the same NaI(Tl) crystal. Agreement to within 5% was observed for all energies considered between the calculated and measured gamma-ray energy resolution results for the NaI(Tl) crystal characterized. The calculated gamma-ray energy resolution results were also compared with previously published gamma-ray energy resolution measurements with good agreement (<10%). In addition to describing the validation technique that was developed in this study and the results, a brief review of the electron energy resolution measurements made using the MCCT is provided. Based on the results of this study, it is believed that the MCCT-measured electron energy resolution results are reliable. Thus, the MCCT and this validation technique can be used in the future to characterize the electron energy resolution of other scintillators and to determine NaI(Tl) intrinsic energy resolution

  11. Improvements in the Tl dosimetry for Radiotherapy

    International Nuclear Information System (INIS)

    Bustos, S.; Velez, G.; Rubio, M.

    1998-01-01

    The thermoluminescent dosimetry (TLD) in vivo has been demonstrated to be one of the most reliable for the control of radiotherapeutic treatments, but the delay in the response is the main disadvantage in its applicability. In this work are presented important improvements and it is demonstrated that maintaining the accuracy and reliability of the technique, it is possible to accelerate the response times at a few hours. To realize this work is utilized a lecturer Harshaw 4000, dosemeters LiF-TLD-100 chips (3.1 x 3.1 x 0.89 mm 3 ) and rods (1 x 1 x 6 mm 3 ). With the implementation of a glow curve analysis program developed in CIEMAT, its obtained a Tl peaks separation in such manner rapid and accurate, by that the thermal treatment of dosemeters may be reduced at one unique annealing pre-irradiation for 1 hr at 400 Centigrade. It is realized a periodical and individual calibration of the TLD and a study of the factors which influencing the ratio Tl signal-dose as linearity, correction by energy, directional response and pride of Tl signal. the results of this study are introducing in a calculation list specially designed and which allows to obtain absorbed dose by TLD starting of the dates (dosimetric peaks area) which appear of the glow curves analysis. The dose is obtained with an accuracy less than 5 %. The dosemeters already irradiated (in vivo) are analysed and informed in only four hours, allowing a greater control of the treatment and a correction of the possible errors for the next session, still in bi fractional treatments. The method implemented results thus accurate, rapid and reliable. (Author)

  12. Unfolding neutron spectra from simulated response of thermoluminescence dosimeters inside a polyethylene sphere using GRNN neural network

    Science.gov (United States)

    Lotfalizadeh, F.; Faghihi, R.; Bahadorzadeh, B.; Sina, S.

    2017-07-01

    Neutron spectrometry using a single-sphere containing dosimeters has been developed recently, as an effective replacement for Bonner sphere spectrometry. The aim of this study is unfolding the neutron energy spectra using GRNN artificial neural network, from the response of thermoluminescence dosimeters, TLDs, located inside a polyethylene sphere. The spectrometer was simulated using MCNP5. TLD-600 and TLD-700 dosimeters were simulated at different positions in all directions. Then the GRNN was used for neutron spectra prediction, using the TLDs' readings. Comparison of spectra predicted by the network with the real spectra, show that the single-sphere dosimeter is an effective instrument in unfolding neutron spectra.

  13. A PC based thin film dosimeter system

    DEFF Research Database (Denmark)

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

    2000-01-01

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

  14. The passive radon-thoron discriminative dosimeter for practical use

    International Nuclear Information System (INIS)

    Doi, Masahiro; Kobayashi, Sadayoshi

    1994-01-01

    A passive radon-thoron discriminative dosimeter for practical use has been developed. The body of the practical R-T dosimeter is made of two hemispheric diffusion chambers of carbonized plastic whose diameters are 110 mm and 70 mm, respectively. These diameters are determined to improve the detection efficiency of radon as well as thoron and also the discrimination ratio of radon to thoron. Inner surface of the detector housing is smooth and free from electrified charge to assure the uniform deposition of radon and thoron progeny, because the detector housing is molded out of carbonized plastic as an anti-static material. In addition, structure of an air inlet has improved to contact more tightly with a glass fiber filter to prevent dust from entering the detector housing. The air inlet of the detector housing is also covered with a half-cutted hemispherical windbreak to protect the glass fiber filter from weathering and to stabilize the influence of convectional air flow on the radon and thoron entry rate into two hemispherical diffusion chambers of the dosimeter. The results of calibration exercises showed that the lower detection limit of radon and thoron concentrations were estimated to be 5.1 Bqm -3 and 7.9 Bqm -3 respectively in 2 months exposure. And an interim measurement in the concrete cellar proved that the practical R-T dosimeter has enough specifications to be used in the large-scale radon-thoron discriminative survey. (author)

  15. Ionizing radiation M.O.S. dosimeters: sensibility and stability

    International Nuclear Information System (INIS)

    Gessinn, F.

    1993-12-01

    This thesis is a contribution to the study of the ionizing radiation responsivity of P.O.M.S. dosimeters. Unlike the development of processing hardening techniques, our works goal were to increase, on the one hand, the M.O.S. dosimeters sensitivity in order to detect small radiation doses and on the other hand, the stability with time and temperature of the devices, to minimize the absorbed-dose estimation errors. With this aim in mind, an analysis of all processing parameters has been carried out: the M.O.S. dosimeter sensitivity is primarily controlled by the gate oxide thickness and the irradiation electric field. Thus, P.M.O.S. transistors with 1 and 2 μm thick silica layers have been fabricated for our experiments. The radiation response of our devices in the high-field mode satisfactorily fits a D ox 2 power law. The maximum sensitivity achieved (9,2 V/Gy for 2μm devices) is close to the ideal value obtained when considering only an unitary carrier-trapping level, and allows to measure about 10 -2 Gy radiation doses. Read-time stability has been evaluated under bias-temperature stress conditions: experiments underscore slow fading, corresponding to 10 -3 Gy/h. The temperature response has also been studied: the analytical model we have developed predicts M.O.S. transistors threshold voltage variations over the military specifications range [-50 deg. C, + 150 deg. C]. Finally, we have investigated the possibilities of irradiated dosimeters thermal annealing for reusing. It appears clearly that radiation-induced damage annealing is strongly gate bias dependent. Furthermore, dosimeters radiation sensitivity seems not to be affected by successive annealings. (author). 146 refs., 58 figs., 9 tabs

  16. Radiation-induced change of optical property of hydroxypropyl cellulose hydrogel containing methacrylate compounds: As a basis for development of a new type of radiation dosimeter

    International Nuclear Information System (INIS)

    Yamashita, Shinichi; Hiroki, Akihiro; Taguchi, Mitsumasa

    2014-01-01

    Hydrogels with matrix of a cellulose derivative, hydrogel of hydroxpropyl cellulose (HPC), containing two of methacrylate compounds (2-hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol) dimethacrylate (9G)) were irradiated with 60 Co γ-rays. The gels become white with irradiation, and thus, could be candidates of a new type of radiation dosimeter utilized in radiation therapy because the gels become white with irradiation and can be confirmed directly by human eyes even at low doses of 1–2 Gy. Radiation-induced change of optical properties, haze value and UV–vis absorption spectrum, of the irradiated gels was measured. Dose response of the white turbidity appearance was different for different compositions of the methacrylate compounds as well as for different dose rates. The degree of the radiation-induced white turbidity was quantified by measuring haze value, showing linear dose response in low dose region (<2 Gy). We also analyzed the gels with a UV–vis spectrometer and HEMA- and 9G-rich gels gave different spectral shapes, indicating that there are at least two mechanisms leading to the white turbidity. In addition, dose rate dependence was smaller for 9G-rich gels than HEMA-rich gels in the range of 0.015–1.5 Gy/min. - Highlights: • White turbidity appeared even at 1 or 2 Gy of 60 Co γ-ray irradiation. • Haze could be used as an index of the degree of white turbidity. • UV–vis spectroscopy indicated multiple mechanisms leading to white turbidity

  17. Integrated circuits from mobile phones as possible emergency OSL/TL dosimeters

    International Nuclear Information System (INIS)

    Sholom, S.; McKeever, S.W.S.

    2016-01-01

    In this article, optically stimulated luminescence (OSL) data are presented from integrated circuits (ICs) extracted from mobile phones. The purpose is to evaluate the potential of using OSL from components in personal electronic devices such as smart phones as a means of emergency dosimetry in the event of a large-scale radiological incident. ICs were extracted from five different makes and models of mobile phone. Sample preparation procedures are described, and OSL from the IC samples following irradiation using a 90 Sr/ 90 Y source is presented. Repeatability, sensitivity, dose responses, minimum measurable doses, stability and fading data were examined and are described. A protocol for measuring absorbed dose is presented, and it was concluded that OSL from these components is a viable method for assessing dose in the days following a radiological incident. (authors)

  18. INTEGRATED CIRCUITS FROM MOBILE PHONES AS POSSIBLE EMERGENCY OSL/TL DOSIMETERS.

    Science.gov (United States)

    Sholom, S; McKeever, S W S

    2016-09-01

    In this article, optically stimulated luminescence (OSL) data are presented from integrated circuits (ICs) extracted from mobile phones. The purpose is to evaluate the potential of using OSL from components in personal electronic devices such as smart phones as a means of emergency dosimetry in the event of a large-scale radiological incident. ICs were extracted from five different makes and models of mobile phone. Sample preparation procedures are described, and OSL from the IC samples following irradiation using a (90)Sr/(90)Y source is presented. Repeatability, sensitivity, dose responses, minimum measureable doses, stability and fading data were examined and are described. A protocol for measuring absorbed dose is presented, and it was concluded that OSL from these components is a viable method for assessing dose in the days following a radiological incident. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-11-11

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

  20. Design of the passive personal dosimeter for miners using an allyl diglycol carbonate plastic. Phase 1

    International Nuclear Information System (INIS)

    1983-12-01

    The report summarizes the results of the feasibility study on the design and development of a passive personal dosimeter incorporating an allyl diglycol carbonate plastic (CR39) detector, for use by uranium miners. Based upon the feasibility study, a passive personal dosimeter using a capacitor-type electrostatic enhancement device has been designed. Preliminary tests indicate that the prototype could be used in the mine environment to differentiate radon and thoron daughters with a detection efficiency comparable to that of a typical active device. Further study is required, however, into the possible influence in the mine environment of local variations in charged fraction, upon the calibration of this dosimeter

  1. An NMR relaxometry and gravimetric study of gelatin-free aqueous polyacrylamide dosimeters

    International Nuclear Information System (INIS)

    Babic, Steven; Schreiner, L John

    2006-01-01

    In conformal radiation therapy, a high dose of radiation is given to a target volume to increase the probability of cure, and care is taken to minimize the dose to surrounding healthy tissue. The techniques used to achieve this are very complicated and the precise verification of the resulting three-dimensional (3D) dose distribution is required. Polyacrylamide gelatin (PAG) dosimeters with magnetic resonance imaging and optical computed tomography scanning provide the required 3D dosimetry with high spatial resolution. Many basic studies have characterized these chemical dosimeters that polymerize under irradiation. However, the investigation of the fundamental properties of the radiation-induced polymerization in PAG dosimeters is complicated by the presence of the background gelatin matrix. In this work, a gelatin-free model system for the study of the basic radiation-induced polymerization in PAG dosimeters has been developed. Experiments were performed on gelatin-free dosimeters, named aqueous polyacrylamide (APA) dosimeters, containing equal amounts of acrylamide and N,N'-methylene-bisacrylamide. The APA dosimeters were prepared with four different total monomer concentrations (2, 4, 6 and 8% by weight). Nuclear magnetic resonance (NMR) spin-spin and spin-lattice proton relaxation measurements at 20 MHz, and gravimetric analyses performed on all four dosimeters, show a continuous degree of polymerization over the dose range of 0-25 Gy. The developed NMR model explains the relationship observed between the relaxation data and the amount of crosslinked polymer formed at each dose. This model can be extended with gelatin relaxation data to provide a fundamental understanding of radiation-induced polymerization in the conventional PAG dosimeters

  2. Standardization of 201Tl and 55Fe radionuclides in a 4 (PC)-NaI(Tl) coincidence system

    International Nuclear Information System (INIS)

    Pires, Carlos Augusto

    2008-01-01

    In the present work the procedure for the standardization of radionuclides using the 4π(PC)-NaI(Tl) coincidence system was developed. The radionuclides selected were 201 Tl, used in nuclear medicine, and 55 Fe primary standard source, used for x-ray spectrometers calibration. The 4π(PC)-NaI(Tl) is composed of a 4 proportional counter operated at 0.1MPa coupled to two NaI(Tl) crystals. The 201 Tl decays by electron capture process followed by a prompt gamma-ray. The disintegration rate was determined by extrapolation technique using two methods: electronic discrimination and external absorbers. The radioactive sources were prepared in a 20 μg cm -2 thick Collodion film. The conventional electronic system was used. The observed events were registered by the TAC method. The 55 Fe decays by electron capture process to the ground state of 55 Mn, emitting x rays with around 6 keV. The standardization was obtained by the tracing method. This technique was applied using two radionuclides, which decay by electron capture process followed by a prompt gamma-ray, namely 51 Cr and 54 Mn, as tracers. Measurements with 1 and 2 aluminum foils, each 150 g cm-2 thick were carried out. The activity was obtained by extrapolation for zero thickness Al foil. The uncertainties were treated by means of matrix covariance methodology and takes into account all correlations involved. (author)

  3. On the Constitution of SoTL: Its Domains and Contexts

    Science.gov (United States)

    Booth, S.; Woollacott, L. C.

    2018-01-01

    In this paper, we present an analysis of the Scholarship of Teaching and Learning in Higher Education (SoTL) which contributes to SoTL both as a field of research practice and as a background to professional development in higher education. We analyse and describe the constitution of the field, and in so doing address its nature in the face of the…

  4. Superconducting transition in TlBiTe/sub 2/ and TlTe compounds

    Energy Technology Data Exchange (ETDEWEB)

    Kantser, V G; Popovich, N S; Sidorenko, A S

    1985-10-01

    On the basis of zone structure calculation for TlBiTe/sub 2/ and TlTe it is found that TlBiTe/sub 2/ is a narrow-gap semiconductor and TlTe is a p-metal. At Tsub(c)=0.19 K TlTe is found to experience the superconducting transition. In TlBiTe/sub 2/ superconductivity is not observed to occur up to 0.05 K, since there is a possibility of occupying the high density of states zones because they are remote from actual ones. The earlier discovered superconducting transition in TlBiTe/sub 2/ is inherent in the alien phase of TlTe.

  5. 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

  6. 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.

  7. 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.

  8. Alpha efficiency under TL and OSL - A subtraction technique using OSL and TL to detect artificial irradiation

    International Nuclear Information System (INIS)

    Zink, A.J.C.; Dabis, S.; Porto, E.; Castaing, J.

    2010-01-01

    With the development of thermoluminescence (TL) and optically stimulated luminescence (OSL) to determine the authenticity of old ceramics, forgers use artificial irradiation by gamma ray to age modern productions. Besides fraudulent action, objects can be exposed to various sources of X-rays (e.g. radiography, security control at airports). For all these reasons, the determination of artificial irradiation is an important topic for dating art objects. The main technique to identify artificial irradiations is the subtraction technique. It is based on the fact that alpha efficiency varies according to the luminescence technique (fine grain, coarse grains, predose, OSL). Having observed a rather significant difference of alpha efficiency for TL and OSL, we propose a new subtraction technique using OSL and TL of fine grains.

  9. Measurement of the dose by dispersed radiation in a lineal accelerator using thermoluminescent dosimeters of CaSO{sub 4}:Dy; Medicion de la dosis por radiacion dispersa en un acelerador lineal usando dosimetros termoluminiscentes de CaSO{sub 4}:Dy

    Energy Technology Data Exchange (ETDEWEB)

    Chavez C, N.; Torijano, E.; Azorin, J. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Herrera, A. [ISSSTE, Hospital Nacional 20 de Noviembre, Eje 7 Sur Felix Cuevas Esq. Av. Coyoacan, Col. del Valle, 03229 Mexico D. F. (Mexico)

    2014-08-15

    The thermoluminescence (Tl) is based on the principle of the luminescent in a material when is heated below their incandescence temperature. Is a technique very used in dosimetry that is based on the property that have most of the crystalline materials regarding the storage of the energy that they absorb when are exposed to the ionizing radiations. When this material has been irradiated previously, the radioactive energy that contains is liberated in form of light. In general, the principles that govern the thermoluminescence are in essence the same of those responsible for all the luminescent processes and, this way, the thermoluminescence is one of the processes that are part of the luminescence phenomenon. For this work, the dispersed radiation was measured in the therapy area of the lineal accelerator of medical use type Elekta, using thermoluminescent dosimeters of CaSO{sub 4}:Dy + Ptfe developed and elaborated in the Universidad Autonoma Metropolitana, Unidad Iztapalapa. With the dosimeters already characterized and calibrated, we proceeded to measure the dispersed radiation being a patient in treatment. The results showed values for the dispersed radiation the order of a third of the dose received by the patient on the treatment table at 30 cm of the direct beam and the order of a hundredth in the control area (4 m of the direct beam, approximately). The conclusion is that the thermoluminescent dosimeters of CaSO{sub 4}: Dy + Ptfe are appropriate to measure dispersed radiation dose in radiotherapy. (author)

  10. Performance testing of extremity dosimeters, Study 2

    International Nuclear Information System (INIS)

    Harty, R.; Reece, W.D.; Hooker, C.D.

    1990-04-01

    The Health Physics Society Standards Committee (HPSSC) Working Group on Performance Testing of Extremity Dosimeters has issued a draft of a proposed standard for extremity dosimeters. The draft standard proposes methods to be used for testing dosimetry systems that determine occupational radiation dose to the extremities and the performance criterion used to determine compliance with the standard. Pacific Northwest Laboratory (PNL) has conducted two separate evaluations of the performance of extremity dosimeter processors to determine the appropriateness of the draft standard, as well as to obtain information regarding the performance of extremity dosimeters. Based on the information obtained during the facility visits and the results obtained from the performance testing, it was recommended that changes be made to ensure that the draft standard is appropriate for extremity dosimeters. The changes include: subdividing the mixture category and the beta particle category; eliminating the neutron category until appropriate flux-to-dose equivalent conversion factors are derived; and changing the tolerance level for the performance criterion to provide consistency with the performance criterion for whole body dosimeters, and to avoid making the draft standard overly difficult for processors of extremity dosimeters to pass. 20 refs., 10 figs., 6 tabs

  11. Working conditions analysis according T.L. personal dosimetry results

    International Nuclear Information System (INIS)

    Marinkovic, O.; Jovanovic, S.

    2006-01-01

    Laboratory for personal dosimetry in the Institute of Occupational and Radiological Health, Belgrade, used TLD more than twenty years. Before that, film dosimetry was main method in external monitoring. T.L. dosimetry was started with Reader Toledo 654 and crystals Mg B 4 O 7 . Finally, from 1992 laboratory has Harshaw TLD Reader Model 6600. Dosimeters are crystals LiF type 100, card packed, worn in standard filtrated holders. Personal dosimetry data are keeping 30 years for each worker according to regulations. The data from 1990 are in electronic form. Long experience enables conclusion that new technique means more advantages in practice. Recommendation from this laboratory practice refers to TLD read-out cycle. The longest period should be one month. LiF is recommended crystal. Glow curve deconvolution gives information about chronological irradiation. It is very important to conclude was dosimetry irradiated by 'one-shot' or continuously. Preparing calibration for determination the time since accident laboratory has to define adequate dose calibration methodology including low temperature peaks. Possibility to follow working conditions analyzing TLD glow curve is much more important than low decrease of dose severity. Time depend analyze is not possible if TLD would be read-out more than (approximately) six weeks after irradiation. If ionizing sources produce such low dose and has negligible probability of accidental exposure (according nowadays regulation read-out frequency could be once in three month), the recommendation is not to use external personal monitoring. Reading personal dosimeters once in three months deemed not useful. Complete and successful personal dosimetry dictates using system that enables glow curve shape representation to be sure that signal is ionizing irradiation result or not. Time depend analyze imparts information about protection permanence. In special circumstance, it is possible to estimate the time of exposure. This is extremely

  12. Study of the reaction {sup 22}O(p,p') with MUST detector. Development of the Cs(Tl) part of MUST-2 detector; Etude de la reaction {sup 22}O(p,p') avec le detecteur MUST. Developpement de l'etage CsI(Tl) de l'ensemble MUST 2

    Energy Technology Data Exchange (ETDEWEB)

    Becheva, E

    2004-11-01

    Elastic and inelastic proton scattering on the unstable nuclei {sup 22}O was measured in inverse kinematics at the GANIL facility. A secondary beam of {sup 22}O at 46.6 MeV/A with intensity of {approx} 1000 pps, impinged on a (CH{sub 2}){sub n} target. Recoiling protons were detected in the silicon strip array MUST. We measured the angular distributions of the ground and 2{sub 1}{sup +} states of {sup 22}O. Phenomenological and microscopic analysis of the data were performed. The phenomenological analysis using a global potential parameterization of Becchetti and Greenlees and CH89 yields a value of the deformation parameter {beta}{sub p,p}, = 0.23{+-}0.04 for {sup 22}O, much lower than that of {sup 20}O. The ratio of neutron and proton matrix element M{sub n}/M{sub p} is found equal to 1.46{+-}0.50. The microscopic analysis used of densities and transition densities calculated within HFB and QRPA models respectively. Optical potential were obtained through both folding and JLM procedures. A ratio M{sub n}/M{sub p}=2.5{+-}1.0 is deduced. Contrary of {sup 20}O, {sup 22}O behaviours like a doubly magic nucleus, suggesting a pronounced sub-shell closure at N=14. To develop the study of direct reactions induced by radioactive beams, we have developed and built, a new multi-detector MUST II devoted to light charged particle detection. In this work we established the requirements for the CsI(Tl) detector stage, and test four CsI detector prototypes, constructed by the SCIONIX company. (author)

  13. Environmental gamma radiation monitoring at Visakhapatnam using thermoluminescence dosimeters

    International Nuclear Information System (INIS)

    Swarnkar, M.; Sahu, S.K.; Takale, R.A.; Shetty, P.G.; Pundit, G.G.; Puranik, V.D.

    2012-01-01

    The gamma rays are the most significant part of environmental dose due to its large range and deep penetrating power. The environmental gamma radiation is mainly originated from two sources natural radiation and artificially produced radiation. The natural radiation dose arises from the cosmic radiation (galactic and solar) and from the Earth (terrestrial) surface. In the last few decades there is a growing concern all over the world about radiation and their exposure to population. Thus it is necessary to conduct radiological environmental surveillance. The radiation survey data are useful to establish the natural background gamma radiation levels. Extensive gamma radiation survey was carried out around the surroundings of Vishakhapatnam using Thermoluminescence Dosimeters (TLDs). The CaSO 4 :(0.2 mole %) Dy Teflon TLD discs, specifically designed for environmental gamma radiation monitoring purpose were used. These TLD badge are having very high TL sensitivity, a negligible fading rate and a stable TL response. TLDs were deployed on quarterly basis for two years to obtain the cumulative gamma background radiation levels in the study area. The radiological survey was also carried out by using a calibrated radiation survey meter. The annual dose rates were computed from quarterly values actually found and normalised to 365 days. The environmental gamma radiation levels around Vishakhapatnam were found to be in the range of 0.79 mGy/y to 1.86 mGy/y. It is clearly seen from the results that location to location there is a large variation in external gamma radiation levels. During the cycle of the TLD survey, spot readings of the background radiation levels were taken, both while placing the TLDs and while removing them. The instantaneous dose rates measured using survey meter, are also following the large variation as found in TLDs. It varies between 110 nGy/hr to 210 nGy/hr. (author)

  14. TL dosimetric characterization of gamma irradiated SrSO{sub 4}:Eu phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Jayasudha, S., E-mail: jsnair.india@gmail.com [Mahatma Gandhi College, Kesavadasapuram, Pattom Palace P.O., Thiruvananthapuram 695004 (India); Madhukumar, K.; Nair, C.M.K.; Nair, Resmi G. [Mahatma Gandhi College, Kesavadasapuram, Pattom Palace P.O., Thiruvananthapuram 695004 (India); Rajesh, S. [Department of Materials & Ceramic Engineering, University of Aveiro, Aveiro 3810-193 (Portugal); Elias, T.S. [State Institute of Cancer Research, Medical College P.O., Thiruvananthapuram 695011 (India); Anandakumar, V.M. [Mahatma Gandhi College, Kesavadasapuram, Pattom Palace P.O., Thiruvananthapuram 695004 (India); State Institute of Cancer Research, Medical College P.O., Thiruvananthapuram 695011 (India); Department of Materials & Ceramic Engineering, University of Aveiro, Aveiro 3810-193 (Portugal); Gopakumar, N. [Mahatma Gandhi College, Kesavadasapuram, Pattom Palace P.O., Thiruvananthapuram 695004 (India)

    2017-03-15

    Thermoluminescence (TL) characteristics of SrSO{sub 4}:Eu nanostructured phosphor under gamma excitation has been studied and their suitability for environmental radiation dosimetry applications is discussed. The dopant level is tuned for optimum TL response. The effect of radiation dose and heating rate were investigated. The phosphor preserves linearity in the low dose region, 0.1 Gy to 20 Gy. PL studies of irradiated and un-irradiated phosphors reveal that the dopant Eu exists in divalent state and are the luminescence emission centres in the material. The fading properties of SrSO{sub 4}:Eu phosphor are observed to be better than that of the commercial dosimeters TLD-200 and TLD-400. The kinetic parameters are calculated using Chen's method and initial rise method and verified by Computerized Glow curve Deconvolution (CGCD). The sensitivity of the synthesized phosphor is found to be very high when compared with that of the commercial standard dosimeter CaSO{sub 4}:Dy. The phosphor is found to be stable for short term radiation monitoring.

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

    DEFF Research Database (Denmark)

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

    2004-01-01

    A method for calibration of thin-film dosimeters irradiated with 80-120keV electrons has been developed. The method is based on measurement of dose with a totally absorbing graphite calorimeter, and conversion of dose in the graphite calorimeter to dose in the film dosimeter by Monte Carlo calcul......V electron irradiation. The two calibrations were found to be equal within the estimated uncertainties of +/-10% at 1 s.d. (C) 2004 Elsevier Ltd. All rights reserved....

  16. Reproducibility and signal response linearity of Alanine gel dosimeter

    International Nuclear Information System (INIS)

    Silva, Cleber Feijo Silva; Campos, Leticia Lucente

    2008-01-01

    Gel Dosimetry has been studied mainly for medical applications, because it presents signal response in the dose range used in radiotherapy treatments and it can be applied for three dimensional dosimetry. Alanine gel dosimeter is a new gel material developed at IPEN that presents significant improvement on previous alanine systems developed by Costa (1994). The DL-Alanine (C 3 H 7 NO 2 ) is an amino acid tissue equivalent that improves the production of ferric ions in the solution. These ferric ions concentration can be measured by spectrophotometry technique. This work aims to study the reproducibility of the alanine gel solutions and the signal response as a function of gamma radiation dose, considering that these two properties are very important for characterizing and standardizing any dosimeter. (author)

  17. Intercomparison measurements with albedo neutron dosimeters

    International Nuclear Information System (INIS)

    Alberts, W.G.; Kluge, H.

    1994-01-01

    Since the introduction of the albedo dosimeter as the official personal neutron dosimeter the dosimetry services concerned have participated in intercomparison measurements at the PTB. Their albedo dosimeters were irradiated in reference fields produced by unmoderated and D 2 O-moderated 252 Cf neutron sources in the standard irradiation facility of the PTB. Six fields with fluences different in energy and angle distribution could be realised in order to determine the response of the albedo dosimeter. The dose equivalent values evaluated by the services were compared with the reference values of the PTB for the directional dose equivalent H'(10). The results turned out to be essentially dependent on the evaluation method and the choice of the calibration factors. (orig.) [de

  18. The shelf life of dyed polymethylmethacrylate dosimeters

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  19. An improved dosimeter having constant flow pump

    International Nuclear Information System (INIS)

    Baker, W.B.

    1980-01-01

    A dosemeter designed for individual use which can be used to monitor toxic radon gas and toxic related products of radon gas in mines and which incorporates a constant air stream flowing through the dosimeter is described. (U.K.)

  20. Floating Gate CMOS Dosimeter With Frequency Output

    Science.gov (United States)

    Garcia-Moreno, E.; Isern, E.; Roca, M.; Picos, R.; Font, J.; Cesari, J.; Pineda, A.

    2012-04-01

    This paper presents a gamma radiation dosimeter based on a floating gate sensor. The sensor is coupled with a signal processing circuitry, which furnishes a square wave output signal, the frequency of which depends on the total dose. Like any other floating gate dosimeter, it exhibits zero bias operation and reprogramming capabilities. The dosimeter has been designed in a standard 0.6 m CMOS technology. The whole dosimeter occupies a silicon area of 450 m250 m. The initial sensitivity to a radiation dose is Hz/rad, and to temperature and supply voltage is kHz/°C and 0.067 kHz/mV, respectively. The lowest detectable dose is less than 1 rad.

  1. Comparison of the TL intensity of the sintered composites of CaSO4+Tm

    International Nuclear Information System (INIS)

    Junot, O.D.; Sousa, F.L. de; Chagas, M.A.P.; Souza, D.N.

    2009-01-01

    The objective of this work is to compare the thermoluminescent intensity (TL) of CaSO 4 +Tm, CaSO 4 +Tm+glass and glass+Tm composites for use as thermoluminescent dosimeter (TLD). The route used to prepare the CaSO 4 +Tm and the CaSO 4 +Tm+glass was by mixing 1 g of CaSO 4 with 0.02 g of thulium oxide (99,9% purity) and 0.3 g of commercial and colorless glass. To mixing the composites were taken to a magnetic stirrer for 30 min with 10 mL of distilled water for better homogenization. The powder mixtures were dried in a stove at 100 deg C for 24 h. After drying, it was added polyvinyl alcohol (PVA) to improve the binding material. The pellets were compacted by application of an uniaxial pressing and sintered at 700 deg C/ 6 h. The route used in the preparation of glass+Tm pellets was similar to one previously mentioned, except by the use of 1 g of glass and 0.02 of Tm. After the sintering, the pellets dimensions were 1 mm thick and 6 mm in diameter. All samples were irradiated by a beta source ( 90 Sr + 90 Y) and received doses from 1.00 Gy to 20 Gy. Each composite presented a characteristic emission curve. The dosimeter of CaSO 4 +Tm+glass presented two peaks, the first at 115 deg C, and the second, very intense, ate 150 deg C. The CaSO 4 +Tm dosimeter showed a less intense peak at 140 deg C and another, more intense, at 235 deg C. In the composites of glass+Tm, the most intense peak has a thermoluminescent signal 94,04% lower than the most intense peak of CaSO 4 +Tm+glass and 81.57% lower than the most intense peak of CaSO 4 +Tm. After the analysis of TL emission curves, we observed that the CaSO 4 +Tm+glass have the highest TL intensity and a TL response proportional to the dose absorbed. (author)

  2. Determination of personnel exposures in the lower energy ranges of X-ray by photographic dosimeter

    International Nuclear Information System (INIS)

    Ha, C.W.; Kim, J.R.; Suk, K.W.

    1986-01-01

    This paper described an improved technical method required for proper evaluation of personnel exposures by means of the photographic dosimeter developed by KAERI in lower gamma or X-ray energy regions, with which response of the dosimeter varies significantly. With calibration of the dosimeter in the energy range from 30 to 300 keV, the beam spectrum was carefully selected and specified it adequately. The absorber combinations and absorber thickness used to obtain the specified X-ray spectra from a constant potential X-ray machine were determined theoretically and also experimentally. A correlation between the density and exposure for the four separate energies, such as 49 keV eff , 154 keV eff 250 keV eff and 662 keV, is experimentally determined. As a result, it can be directly evaluated the exposure from the measured response of dosimeter. (Author)

  3. Mayak Film Dosimeter Response Studies Part III: Application to Worker Dose Assessment

    International Nuclear Information System (INIS)

    Smetanin, Mikhail; Vasilenko, E. K.; Scherpelz, Robert I.

    2007-01-01

    This paper describes the methods used to convert individual dosimeter readings for workers to obtain estimates of worker doses received in Mayak facilities. Film dosimeters were used at Mayak PA for worker monitoring from 1948 until 1992. The method requires a determination of the relationship between the absorbed dose in film emulsion and the dose in air under calibration conditions, then an extension of this relationship to exposures in the actual radiation fields of the workplace. Corrections needed to account for actual workplace exposure conditions were determined by modeling with the Monte-Carlo radiation transport computer code MCNP. Correction factors were developed to convert from dosimeter reading to a realistic worker dose. The method was applied as a basis for individual dose reconstruction using film dosimeters in realistic photon spectra and geometries at Mayak PA work areas

  4. Perfection of the individual photographic emulsion dosimeter

    International Nuclear Information System (INIS)

    Soudain, G.

    1960-01-01

    A photographic dosimeter making possible the measurement of γ radiation doses of from 10 mr up to 800 r by means of 3 emulsion bands of varying sensitivity stuck to the same support is described. The dosimeter has also a zone for marking and a test film insensitive to radiation. This requires a photometric measurement by diffuse reflection an d makes it possible to measure doses with an accuracy of 20 per cent. (author) [fr

  5. Prolate yrast cascade in 183Tl

    International Nuclear Information System (INIS)

    Reviol, W.; Carpenter, M. P.; Janssens, R. V. F.; Jenkins, D.; Toth, K. S.; Bingham, C. R.; Riedinger, L. L.; Weintraub, W.; Cizewski, J. A.; Lauritsen, T.

    2000-01-01

    The yrast sequence in 183 Tl has been studied for the first time in recoil-mass selected γ-ray spectroscopic measurements. A rotational-like cascade of seven transitions is established down to the band head with probable spin and parity (13/2 + ). Unlike in the adjacent odd-mass Tl nuclei, prompt γ decay from the yrast band to a lower lying weakly deformed (oblate) structure is not observed. These features are consistent with the predicted drop of the prolate band head in 183 Tl compared to 185 Tl. The implications for the prolate energy minimum in odd-mass Tl nuclei at the neutron i 13/2 midshell (N=103) are discussed. (c) 2000 The American Physical Society

  6. Intercomparison of high energy neutron personnel dosimeters

    International Nuclear Information System (INIS)

    McDonald, J.C.; Akabani, G.; Loesch, R.M.

    1993-03-01

    An intercomparison of high-energy neutron personnel dosimeters was performed to evaluate the uniformity of the response characteristics of typical neutron dosimeters presently in use at US Department of Energy (DOE) accelerator facilities. It was necessary to perform an intercomparison because there are no national or international standards for high-energy neutron dosimetry. The testing that is presently under way for the Department of Energy Laboratory Accreditation Program (DOELAP) is limited to the use of neutron sources that range in energy from about 1 keV to 2 MeV. Therefore, the high-energy neutron dosimeters presently in use at DOE accelerator facilities are not being tested effectively. This intercomparison employed neutrons produced by the 9 Be(p,n) 9 B interaction at the University of Washington cyclotron, using 50-MeV protons. The resulting neutron energy spectrum extended to a maximum of approximately 50-MeV, with a mean energy of about 20-MeV. Intercomparison results for currently used dosimeters, including Nuclear Type A (NTA) film, thermoluminescent dosimeter (TLD)-albedo, and track-etch dosimeters (TEDs), indicated a wide variation in response to identical doses of high-energy neutrons. Results of this study will be discussed along with a description of plans for future work

  7. Polymer gel dosimeter based on itaconic acid

    International Nuclear Information System (INIS)

    Mattea, Facundo; Chacón, David

    2015-01-01

    A new polymeric dosimeter based on itaconic acid and N, N’-methylenebisacrylamide was studied. The preparation method, compositions of monomer and crosslinking agent and the presence of oxygen in the dosimetric system were analyzed. The resulting materials were irradiated with an X-ray tube at 158 cGy/min, 226 cGy min and 298 cGy/min with doses up to 1000 Gy. The dosimeters presented a linear response in the dose range 75–1000 Gy, sensitivities of 0.037 1/Gy at 298 cGy/min and an increase in the sensitivity with lower dose rates. One of the most relevant outcomes in this study was obtaining different monomer to crosslinker inclusion in the formed gel for the dosimeters where oxygen was purged during the preparation method. This effect has not been reported in other typical dosimeters and could be attributed to the large differences in the reactivity among these species. - Highlights: • A novel polymer gel dosimeters based on itaconic acid is presented and characterized. • The typical linear trend of the dose behavior in a specific dose range was found. • Different gel structures were formed when oxygen and an antioxidant were present. • Absorbed dose is univocally correlated with optic absorbance and Raman spectroscopy. • Itaconic acid appears as a reliable radiation dosimeter that may be further improved.

  8. Comparative study of some new EPR dosimeters

    International Nuclear Information System (INIS)

    Alzimami, K.S.; Maghraby, Ahmed M.; Bradley, D.A.

    2014-01-01

    Investigations have been made of four new radiation dosimetry EPR candidates from the same family of materials: sulfamic acid, sulfanillic acid, homotaurine, and taurine. Mass energy attenuation coefficients, mass stopping power values and the time dependence of the radiation induced radicals are compared. Also investigated are the microwave saturation behavior and the effect of applied modulation amplitude on both peak-to-peak line width (W PP ) and peak-to-peak signal height (H PP ). The dosimeters are characterized by simple spectra and stable radiation-induced radicals over reasonable durations, especially in taurine dosimeters. Sulfamic acid dosimeters possessed the highest sensitivity followed by taurine and homotaurine and sulfanillic. - Highlights: ► Several EPR dosimeters were suggested based on SO 3 − radical. ► Taurine, homotaurine, sulfanilic, and sulfamic acid all possess simple EPR spectra. ► Dosimeters were compared to each other in terms of the dosimetric point of view. ► Energy dependence curves of the selected dosimeters were compared to eachother

  9. Design and test of a scintillation dosimeter for dosimetry measurements of high energy radiotherapy beams

    International Nuclear Information System (INIS)

    Fontbonne, J.M.

    2002-12-01

    This work describes the design and evaluation of the performances of a scintillation dosimeter developed for the dosimetry of radiation beams used in radiotherapy. The dosimeter consists in a small plastic scintillator producing light which is guided by means of a plastic optical fiber towards photodetectors. In addition to scintillation, high energy ionizing radiations produce Cerenkov light both in the scintillator and the optical fiber. Based on a wavelength analysis, we have developed a deconvolution technique to measure the scintillation light in the presence of Cerenkov light. We stress the advantages that are anticipated from plastic scintillator, in particular concerning tissue or water equivalence (mass stopping power, mass attenuation or mass energy absorption coefficients). We show that detectors based on this material have better characteristics than conventional dosimeters such as ionisation chambers or silicon detectors. The deconvolution technique is exposed, as well as the calibration procedure using an ionisation chamber. We have studied the uncertainty of our dosimeter. The electronics noise, the fiber transmission, the deconvolution technique and the calibration errors give an overall combined experimental uncertainty of about 0,5%. The absolute response of the dosimeter is studied by means of depth dose measurements. We show that absolute uncertainty with photons or electrons beams with energies ranging from 4 MeV to 25 MeV is less than ± 1 %. Last, at variance with other devices, our scintillation dosimeter does not need dose correction with depth. (author)

  10. 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

  11. Medical extrapolation chamber dosimeter model XW6012A

    International Nuclear Information System (INIS)

    Jin Tao; Wang Mi; Wu Jinzheng; Guo Qi

    1992-01-01

    An extrapolation chamber dosimeter has been developed for clinical dosimetry of electron beams and X-rays from medical linear accelerators. It consists of a new type extrapolation chamber, a water phantom and an intelligent portable instrument. With a thin entrance window and a φ20 mm collecting electrode made of polystyrene, the electrode spacing can be varied from 0.2 to 6 mm. The dosimeter can accomplish dose measurement automatically, and has functions of error self-diagnosis and dose self-recording. The energy range applicable is 0.5-20 MeV, and the dose-rate range 0.02-40 Gy/min. The total uncertainty is 2.7%

  12. Investigations of CR39 dosimeters for neutron routine dosimetry

    International Nuclear Information System (INIS)

    Weinstein, M.; Abraham, A.; Tshuva, A.; German, U.

    2004-01-01

    CR-39 is a polymeric nuclear track detector which is widely used for neutron dosimetry. CR-39 detector development was conducted at a number of laboratories throughout the world(1,2) , and was accepted also for routine dosimetry. However, there are shortcomings which must be taken into consideration the lack of a dosimetry grade material which causes batch variations, significant angular dependence and a moderate sensitivity. CR-39 also under-responds for certain classes of neutron spectra (lower energy neutrons from reactors or high energy accelerator-produced neutrons).In order to introduce CR-39 as a routine dosimeter at NRCN, a series of checks were performed. The present work describes the results of some of our checks, to characterize the main properties of CR-39 dosimeters

  13. Electronic personal dosimeter heralds a revolution in legal dosimetry

    International Nuclear Information System (INIS)

    Fletcher, R.

    1991-01-01

    The Electronic Personal Dosimeter (EPD) developed by Siemens Plessey Controls and the UK's national Radiological Protection Board is approaching the pre-production stage. It provides ''legal'' dosimetry and all the features of a personal alarming dosimeter. The EPD uses solid state semiconductor detectors for gamma and beta radiation and has a dose threshold of about 1μ Sv, with a low energy gamma range down to 20 KeV. It has a multi function liquid crystal display for instant readout and audible and visual alarms. Two separates dose stores are maintained. Short term dose for tactical management and long term dose for approved dosimetry service record keeping. The latter can be reset only by an approved dosimetry service and is maintained on a search memory disk which can be read even if the EPD is destroyed. (UK)

  14. An improved design of QFE dosimeter charging unit

    International Nuclear Information System (INIS)

    Speight, R.G.; Clifton, J.J.

    1976-02-01

    The availability of commercial charging units for quartz fibre electroscope dosimeters (QFEs) in the United Kingdom has been limited to small battery units intended for use in laboratory conditions. The use of large numbers of QFEs by semi-skilled staff has resulted in damage to many dosimeters, particularly at the charging pins. Difficulties have also been experienced in the viewing of the scale and fibre in non-laboratory lighting conditions. These problems have resulted in the development of a robust charging and viewing unit, which is described in this report. The new unit which is mains electricity powered, is contained in a case 230 x 305 x 150 mm weighing 4.5 kg. (U.K.)

  15. Thermoluminescent dosimeters for low dose X-ray measurements

    International Nuclear Information System (INIS)

    Del Sol Fernández, S.; García-Salcedo, R.; Sánchez-Guzmán, D.; Ramírez-Rodríguez, G.; Gaona, E.; León-Alfaro, M.A. de; Rivera-Montalvo, T.

    2016-01-01

    The response of TLD-100, CaSO_4:Dy and LiF:Mg,Cu,P for a range of X-ray low dose was measured. For calibration, the TLDs were arranged at the center of the X-ray field. The dose output of the X-ray machine was determined using an ACCU-Gold. All dosimeters were exposed at the available air kerma values of 14.69 mGy within a field 10×10 cm"2 at 80 cm of SSD. Results of LiF:Mg,Cu,P X-ray irradiated showed 4.8 times higher sensitivity than TLD-100. Meanwhile, TL response of CaSO_4:Dy exposed at the same dose was 5.6 time higher than TLD-100. Experimental results show for low dose X-ray measurements a better linearity for LiF:Mg,Cu,P compared with that of TLD-100. CaSO_4:Dy showed a linearity from 0.1 to 60 mGy - Highlights: • Low dose X-ray doses for personal dosimetry were measured. • Radiation dose (µGy ) for environmental dosimetry were determined. • Scattering radiation dose were measured by TLDs. • Linearity of pair TLD system was successful in the range of microgray. • Pair TLDs composed by CaSO_4:Dy and by LiF:Mg,Cu,P. is suggested for clinical dosimetry.

  16. Evaluation of aluminum oxide dosimeters using OSL technique in dosimetry of clinical photon beams on volumetric modulated arc treatment

    International Nuclear Information System (INIS)

    Villani, Daniel

    2017-01-01

    Treatment using Volumetric Modulated Arc Radiation Therapy is the most modern modality of conformational radiotherapy so that, with the overlapping of several fields, the dose distributions provide a perfect conformation to the tumor, reducing the probability of complications in adjacent normal tissues. In this sense, many efforts are being invested to improve dose distribution compliance as well as the integration of imaging techniques for tumor screening and correction of inter and intrafraction variations. To this end, an intensive monitoring of the quality of the processes and a quality assurance program are fundamental for patient safety and compliance with current legislation; besides the use of different dosimetry methodologies for intercomparison and validation of the results. The aim of this study is to evaluate and compare the performance of aluminum oxide (Al_2O_3:C) OSL dosimeters manufactured by Landauer Inc. with those produced by Rexon™ in the dosimetry of high energy photon clinical bundles used in Volumetric Modulated Arc Therapy - (VMAT) using different simulating objects. The dosimeters were characterized for gamma radiation of the "6"0Co and for clinical photon beams of 6 MV typical of treatments by VMAT under conditions of electronic equilibrium and maximum dose respectively. Performance tests of the TL and OSL readers used and repeatability of the samples were evaluated. After all tests, the dosimeters were irradiated in the simulation of different radiotherapy treatments by VMAT and their responses compared to the planning system. All types of dosimeters presented satisfactory results in verifying the doses of this type of planning simulation. The Al_2O_3:C dosimeters presented compatible results and validated by the other dosimeters and ionization chamber. Regarding the best technique, the OSL InLight commercial system presents greater practicality and versatility for use and application in the clinical routine. (author)

  17. Improvements in the Tl dosimetry for Radiotherapy; Mejoras en la dosimetria Tl para Radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Bustos, S.; Velez, G.; Rubio, M. [CEPROCOR. Arenales 230 Juniors Cordoba 5000 (Argentina)

    1998-12-31

    The thermoluminescent dosimetry (TLD) in vivo has been demonstrated to be one of the most reliable for the control of radiotherapeutic treatments, but the delay in the response is the main disadvantage in its applicability. In this work are presented important improvements and it is demonstrated that maintaining the accuracy and reliability of the technique, it is possible to accelerate the response times at a few hours. To realize this work is utilized a lecturer Harshaw 4000, dosemeters LiF-TLD-100 chips (3.1 x 3.1 x 0.89 mm{sup 3}) and rods (1 x 1 x 6 mm{sup 3}). With the implementation of a glow curve analysis program developed in CIEMAT, its obtained a Tl peaks separation in such manner rapid and accurate, by that the thermal treatment of dosemeters may be reduced at one unique annealing pre-irradiation for 1 hr at 400 Centigrade. It is realized a periodical and individual calibration of the TLD and a study of the factors which influencing the ratio Tl signal-dose as linearity, correction by energy, directional response and pride of Tl signal. the results of this study are introducing in a calculation list specially designed and which allows to obtain absorbed dose by TLD starting of the dates (dosimetric peaks area) which appear of the glow curves analysis. The dose is obtained with an accuracy less than 5 %. The dosemeters already irradiated (in vivo) are analysed and informed in only four hours, allowing a greater control of the treatment and a correction of the possible errors for the next session, still in bi fractional treatments. The method implemented results thus accurate, rapid and reliable. (Author)

  18. Technology development for evaluation of operational quantities in radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jang Lyul; Chang, S. Y.; Lee, L. T.; Kim, B. H.; Chung, K. K.; Lee, J. I.; Lim, G. S.; Kim, J. S.; Nam, Y. M.; Chang, J. K.; Kim, D. Y.; Yang, J. S

    2000-03-01

    A study on the fabrication of a new personal thermo-luminescence dosimeter, which can evaluate the personal dose equivalent H{sub p}(d), has been performed. Optimum conditions for fabrication of a LiF:Mg,Cu,Na,Si TL phosphor powder has been determined and a disc type TL pellet has been fabricated from this TL powder. Another type of CaSO{sub 4}:Dy,Mo TL material has been also fabricated. These two TL materials have shown greater TL sensitivity than the foreign-made commercial TL materials. Mono-energetic fluorescence X-ray from 8.6 keV to 75 keV for use in performance testing of the developed TLDs energy response have been constructed and evaluated for the performance of the purity, air kerma, beam uniformity and distribution, and scattered fraction of X-rays. Reference neutron field of a D{sub 2}O moderated {sup 252}Cf source was characterized and the irradiation system using {sup 226}Ra and {sup 137}Cs sources was installed to construct the environmental gamma reference radiation and the low-level gamma radiation. A capability of calibration and measurement of KAERI In Vivo counting system for transuranic elements in the lung has been evaluated through the participation in the overseas intercomparison study on the In Vivo radioactivity measurement. An improvement and advancement of KAERI lung counting technology have been made by the analysis off uncertainties from the assumption of uniform radioactivity distribution in the lung, experimental determination and comparing of detection efficiency with different lung sets, and mathematical efficiency calibration of In Vivo counting system. (author)

  19. A gelatin-free model system for the study of the basic radiation-induced polymerization in PAG dosimeters

    International Nuclear Information System (INIS)

    Babic, S; Park, Y S; Schreiner, L J

    2004-01-01

    In this presentation we show results of investigations on gelatin-free dosimeters containing equal amounts of acrylamide and N,N'-methylene-bisacrylamide (named Aqueous Polyacrylamide, APA, dosimeters). The dosimeters were prepared with three different total monomer concentrations (2, 6, and 8% by weight). Nuclear magnetic resonance (NMR) spin-spin and spin-lattice proton relaxation measurements at 20 MHz, and gravimetric analyses performed on all three dosimeters, show a continuous degree of polymerization over the range of dose 0.5 - 25 Gy. The developed NMR model explains the relationship observed between the relaxation data and the amount of cross-linked polymer formed at each dose. This model may be extended with gelatin relaxation data to provide a fundamental understanding of radiation-induced polymerization in the conventional PAG dosimeters

  20. Application of TL dosimetry in epidemiological studies in HBRAs

    International Nuclear Information System (INIS)

    Chougaonkar, M.P.

    2006-01-01

    Luminescence as a phenomenon has been extensively used in radiation dosimetry, using thermoluminescence. The nuclear industry all over the world over uses TL dosimetry in radiation protection since they have to ensure that the radiation workers and workers involved in industrial applications of radiation sources are not exposed beyond limits set by international monitoring bodies. They have also to ensure that the nuclear applications do not give rise to elevated radiation levels in the environs. In addition, epidemiologists and radiobiologists world over have been working over the past few decades, to study health effects of chronic radiation exposures in populations living in the elevated natural radiation environment. This paper discusses the importance of dosimetric studies, in the normal as well as high background radiation areas (HBRAs), due to the radiation effects on the humans. The application of thermoluminescent dosimeters (TLDs) in population dosimetry with the end point of epidemiological studies is then discussed. The paper outlines the construction of TLDs, methodology of deployment and retrieval and analysis to arrive the dose. To obtain total dose, dosimetric techniques suitable for external gamma radiation, inhalation dose due to radon, thoron and their progenies and radiological analysis of the food items is required. The techniques arriving at the effective dose are outlined. Basics of epidemiological analysis, particularly using case-control methodology and its advantages/ disadvantages are also discussed. Using the previous work by the author, the paper also reviews various analyses that can be carried out the dosimetric data. (author)

  1. An environmental BeO-OSL dosimeter for emergency response

    International Nuclear Information System (INIS)

    Woda, Clemens; Kaiser, Jan Christian; Urso, Laura; Greiter, Matthias

    2012-01-01

    A conceptual design is presented to use measurements of localized absorbed dose in inner cities for production of high resolution maps of the radioactive contamination following a nuclear emergency or radiological attack. The doses are derived from luminescent detectors pre-fixed at places of high importance (e.g. public squares). For such an environmental dosimeter, BeO is used, which can be read out using optically stimulated luminescence (OSL). A suitable casing of black Perspex has been developed to give a sufficiently accurate estimate of the air kerma value at the detector position. The dosimeter is characterized according to light tightness, dose response and angular photon energy dependence. A short overview of the approach for map production is also given. - Highlights: ► An inexpensive, environmentally stable BeO based OSL dosimeter has been developed for emergency response. ► The detector enables fast readouts and shows highly favorable dosimetric properties. ► A conceptual design is described to produce maps of radioactive contamination from localized dose measurements in urban areas.

  2. TH-CD-201-08: Flexible Dosimeter Bands for Whole-Body Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Kim, T; Fahimian, B; Pratx, G [Department of Radiation Oncology, Stanford University, Palo Alto, CA (United States)

    2016-06-15

    Purpose: The two commonly used radiotherapy techniques are total body irradiation (TBI) and the total skin irradiation (TSI). In order to ensure the accuracy of the prescription beams, the dose received throughout the entire body must be checked using dosimetry. However, the available number of data points is limited as the dosimeters are manually placed on the patient. We developed a flexible and wearable dosimeter that can collect 1D continuous dose information around the peripheral of the patients’ body, including areas obscured from the beam path. Methods: The flexible dosimeter bands are fabricated by embedding storage phosphor powders in a thin layer of non-toxic silicone based elastomer (PDMS). An additional elastomer layer is formed on top of the phosphor layer to provide additional mechanical support for the dosimeter. Once the curing process is complete, the dosimeter is cut into multiple bands and rolled into spools prior to use. Results: The dose responses are tested using a preclinical cabinet X-ray system, where the readout is performed with a storage phosphor reader. Results show that the dose calibration factor is ∼1400 (A.U./Gy) from the beam center. Also, 1-D dose distribution experiment was performed in water phantoms, where preliminary results demonstrate that the dose in water is indeed attenuated compared to in air. Conclusion: Dose response and high-resolution 1-D dosimetry is demonstrated using the flexible dosimeters. By providing a detailed spatial description of the beam dose profile, we expect that the dosimeter bands may aid in enhancing the current existing modality in dosimetry. Since the dosimeter is flexible (can retract back to its original length), they can be comfortably worn around the patient. Potentially, multiple 1-D dose information can be stitched together and extrapolated to provide a coarse 3-D image of the dose distribution. This work was supported by funding from the Cutaneous Lymphoma Foundation under the CLARIONS

  3. TH-CD-201-08: Flexible Dosimeter Bands for Whole-Body Dosimetry

    International Nuclear Information System (INIS)

    Kim, T; Fahimian, B; Pratx, G

    2016-01-01

    Purpose: The two commonly used radiotherapy techniques are total body irradiation (TBI) and the total skin irradiation (TSI). In order to ensure the accuracy of the prescription beams, the dose received throughout the entire body must be checked using dosimetry. However, the available number of data points is limited as the dosimeters are manually placed on the patient. We developed a flexible and wearable dosimeter that can collect 1D continuous dose information around the peripheral of the patients’ body, including areas obscured from the beam path. Methods: The flexible dosimeter bands are fabricated by embedding storage phosphor powders in a thin layer of non-toxic silicone based elastomer (PDMS). An additional elastomer layer is formed on top of the phosphor layer to provide additional mechanical support for the dosimeter. Once the curing process is complete, the dosimeter is cut into multiple bands and rolled into spools prior to use. Results: The dose responses are tested using a preclinical cabinet X-ray system, where the readout is performed with a storage phosphor reader. Results show that the dose calibration factor is ∼1400 (A.U./Gy) from the beam center. Also, 1-D dose distribution experiment was performed in water phantoms, where preliminary results demonstrate that the dose in water is indeed attenuated compared to in air. Conclusion: Dose response and high-resolution 1-D dosimetry is demonstrated using the flexible dosimeters. By providing a detailed spatial description of the beam dose profile, we expect that the dosimeter bands may aid in enhancing the current existing modality in dosimetry. Since the dosimeter is flexible (can retract back to its original length), they can be comfortably worn around the patient. Potentially, multiple 1-D dose information can be stitched together and extrapolated to provide a coarse 3-D image of the dose distribution. This work was supported by funding from the Cutaneous Lymphoma Foundation under the CLARIONS

  4. Comparison of Panasonic’s Dosimetric System with Gamma-31 Dosimeters

    Directory of Open Access Journals (Sweden)

    Paweł Urban

    2013-01-01

    Full Text Available Equipment being used in medical or industrial institutions is often a source of ionizing radiation with different energies and types, which complicates the detection and assessment of doses. Up until now, for dosimetric measurements of ionizing radiation, Gamma-31 dosimeters have been used in the Central Mining Institute for many years. Now, this system will be expanded by a Panasonic system, for which measurement procedures were developed and comparisons with other dosimeters were held. The method is based on a four-element dosimeters UD-802 Panasonic equipped with CaSO and LiBO detectors additionally sheltered by filters of different surface mass. The use of UD-802 dosimeters, in contrast to Gamma-31 dosimeters, permits measuring radiation doses in a different range of photon energy. Consequently, it is possible to obtain a more accurate analysis of the hazards caused by gamma radiation in underground mines. The publication includes a description of the dosimetry system and presents the results of measurements conducted by means of both types of dosimeters. In order to verify the correctness of the indications of the new dosimetry system a series of measurements were carried out, which allowed examining the behaviour of the dosimeters under different environmental conditions. As a place of exposure, the selected laboratories in the Silesian Centre for Environmental Radiometry were chosen, where the work is connected with (TENORM and equipment producing ionizing radiation or containing sources of this type of radiation. Moreover, to observe the dosimeters behaviour in difficult environmental conditions, they were exposed in water treatment plants and an underground potassium salt mine.

  5. High current Tl-203, Rh-103 targets preparation for cyclotron production of Tl-201 and Pd-103 radionuclides

    International Nuclear Information System (INIS)

    Arzumanov, A.; Berger, V.; Borissenko, A.; Gorodisskaya, N.; Ilmatov, I.; Knyazev, A.; Koptev, V.; Lyssukhin, S.; Platov, A.; Sychikov, G.; Zheltov, D.

    2004-01-01

    The objectives of the present work are to increase thermal stability of cyclotron targets for production of Tl-201 isotope, increase Tl-203 regeneration rate at radiochemical reprocessing of the targets and develop production technology for radiochemical sources based on Rd-103 isotope. Electrochemical coating of copper substrate with Tl increased the beam current at target irradiation from 100 μA to 125 μA. Further increase of the beam current results in sharp decrease of target stability time at irradiation to 15 min at beam current 150 μA. Thermal calculations and tests at the electron-beam stand predict satisfactory stability at such currents. The discrepancy with the irradiation results has not been explained. More accurate specification of regimes for Tl-203 electrochemical recovery from irradiated targets and better matching of the electrolyte composition made it possible to increase the recovery rate up to 99.5%. Before the present Project, the INP had no experience in production of radioactive sources based on Pd-103. Thermo-diffusion extraction of Pd-103 from irradiated rhodium foil has been chosen as a technology-defining method. The process assures good extraction rate and high purity of extracted isotope. Production of Pd-103 sources based on this technology is much simpler compared to the same based on electrochemical processes. (author)

  6. TH-CD-201-11: Optimizing the Response and Cost of a DNA Double-Strand Break Dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Obeidat, M; Cline, K; Stathakis, S; Papanikolaou, N; Rasmussen, K; Gutierrez, A; Ha, CS; Lee, SE; Shim, EY; Kirby, N [University of Texas HSC SA, San Antonio, TX (United States)

    2016-06-15

    Purpose: A DNA double-strand break (DSB) dosimeter was developed to measure the biological effect of radiation. The goal here is to refine the fabrication method of this dosimeter to reproducibly create a low coefficient of variation (CoV) and reduce the cost for the dosimeter. Methods: Our dosimeter consists of 4 kilo-base pair DNA strands (labeled on one end with biotin and on the other with fluorescein) attached to streptavidin magnetic beads. The final step of the DNA dosimeter fabrication is to suspend these attached beads in phosphate-buffered saline (PBS). The amount of PBS used to suspend the attached beads and the relative volume of the DNA strands to the beads both affect the CoV and dosimeter cost. We diluted the beads attached with DNA in different volumes of PBS (100, 200, and 400 µL) to create different concentrations of the DNA dosimeter. Then we irradiated these dosimeters (50 µL samples) in a water-equivalent plastic phantom at 25 and 50 Gy (three samples per dose) and calculated the CoV for each dosimeter concentration. Also, we used different masses of DNA strands (1, 2, 8, 16, 24, and 32 µg) to attach to the same volume of magnetic beads (100 µL) to explore how this affects the cost of the dosimeter. Results: The lowest CoV was produced for the highest concentration of dosimeter (100 µL of PBS), which created CoV of 2.0 and 1.0% for 25 and 50 Gy, respectively. We found that the lowest production cost for the dosimeter occurs by attaching 16 µg of DNA strands with 100 µL of beads. Conclusion: : We optimized the fabrication of the DNA dosimeter to produce low CoV and cost, but we still need to explore ways to further improve the dosimeter for use at lower doses. This work was supported in part by Yarmouk University (Irbid, Jordan) and CPRIT (RP140105)

  7. Synthetic diamond devices for radiotherapy applications: Thermoluminescent dosimeter and ionisation chamber

    International Nuclear Information System (INIS)

    Descamps, C.; Tromson, D.; Mer, C.; Nesladek, M.; Bergonzo, P.

    2006-01-01

    In radiotherapy field, the major usage of dosimeters is in the measurement of the dose received by the patient during radiotherapy (in-vivo measurements) and in beam calibration and uniformity checks. Diamond exhibits several interesting characteristics that make it a good candidate for radiation detection. It is indeed soft-tissue equivalent (Z=6 compared to Z=7.42 for human tissue), mechanically robust and relatively insensitive to radiation damage, chemically stable and non toxic. Moreover, the recent availability of synthetic samples, grown under controlled conditions using the chemical vapour deposition (C.V.D.) technique, allowed decreasing the high cost and the long delivery time of diamond devices. Diamond can be use for off-line dosimetry as thermoluminescent dosimeters or for on-line dosimetry as ionisation chamber [2,3]. These both applications are reported here. For this study, samples were grown in the laboratory and devices were then tested under X-ray irradiations and in clinical environment under medical cobalt source. The work described in this paper was performed in the framework of the European Integrated Project M.A.E.S.T.R.O., Methods and Advanced Equipment for Simulation and Treatment in Radio-Oncology, (6. FP) which is granted by the European Commission.The first results of this study clearly show that C.V.D. diamond detectors are suitable for dosimetry in radiotherapy applications. Moreover, for both T.L. dosimeters and ionisation chambers applications, and even though the sensitivity is subsequently reduced, nitrogen incorporation in films seems to significantly improve the dosimetric characteristics of the devices. Therefore, the optimisation of the material quality appears as a very important issue in order to increase the dosimetric characteristics of devices and more particularly, for use as thermoluminescent dosimeters, other impurities (Nickel, Phosphorus) will be tested. For ionisation chamber applications, experiments with

  8. Characteristics and application of alanine dosimeter 'Aminogray'

    International Nuclear Information System (INIS)

    Kashiwazaki, Shigeru; Matsuyama, Shigeki; Hatta, Toshimasa; Yagyu, Hideki; Kojima, Takuji; Tanaka, Ryuichi; Morita, Yohsuke.

    1988-01-01

    Recently, accompanying the progress of nuclear power generation and space development, the evaluation of reliability for the materials and parts used under irradiation has become important. For the evaluation of reliability, the accurate grasp of radiation dose is the prerequisite. In some case, the measurement of cumulative dose in a long period in an actual environment becomes necessary. In this paper, the characteristics and application of a new dosimeter element 'Aminogray' which is suitable to the above requirement are reported. Aminogray is rodshape element made by forming alanine, a kind of amino acid, using a binder polymer, and the alanine content is 70 wt.%, and the polymer is polystyrene. An element of 3 mm diameter and 30 mm length is enclosed in a polystyrene cylinder of 4 mm thickness. This thickness was determined by considering the electronic equilibrium condition in Co-60 gamma-ray irradiation. The principle of the measurement is to determine a dose by measuring the amount of free radicals produced in alanine by radiation using ESR method. The free radicals are extremely stable, and exist for a long period, and the amount of radical production is proportional to absorbed dose. The development, characteristics and application of Aminogray are reported. (K.I.)

  9. Design and Implementation of Accurate and Efficient Pocket Dosimeter

    International Nuclear Information System (INIS)

    Shehata, S.A.; Abdelkhalek, K.L.

    2005-01-01

    It is so important in the field of radiation therapy and radiation protection to have dosimeters to determine the absorbed dose, which is transferred to human body by ionizing radiation. In this paper the design and implementation of a wide-range pocket dosimeter (PKD-1) with high accuracy to measure personal equivalent dose and dose rate of gamma radiation will be presented. This pocket dosimeter is micro controller-based and powered from 9 V rechargeable battery. The overall power consumption is significantly reduced by smart software and hardware design allowing longer time intervals between recharging. The integrated alphanumerical LCD displays not only of the accumulated dose and current dose rate, but also displays alarm messages such as low battery. For reasons of power saving the LCD is activated on demand by pressing the push button or automatically when an alarm occurs. Audible and visual alarms have been added to PKD-1 in order that they cannot be accidentally overlooked or ignored. PKD-1 can be connected to any PC through its serial port (RS232) and User Interface software has been developed for easy displaying and recording of radiation readings over any time period

  10. Latest developments in silica fibre luminescence dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, D. A.; Abdul S, S. F.; Jafari, S. M.; Alanazi, A. [University of Surrey, Department of Physics, GU2 7XH Guildford, Surrey (United Kingdom); Amouzad M, G. [University of Malaya, Faculty of Engineering, Department of Electrical Engineering, Integrated Lightwave Research Group, 50603 Kuala Lumpur (Malaysia); Addul R, H. A.; Mizanur R, A. K. M.; Zubair, H. T.; Begum, M.; Yusoff, Z.; Omar, N. Y. M. [Multimedia University, Faculty of Engineering, 2010 Cyberjaya, Selangor (Malaysia); Maah, M. J. [University of Malaya, Department of Chemistry, 50603 Kuala Lumpur (Malaysia); Collin, S. [National Physical Laboratory, Hampton Road, Teddington, TW11 OLW Middlesex (United Kingdom); Mat-Sharif, K. A.; Muhd-Yassin, S. Z.; Zulkifli, M. I., E-mail: d.a.bradley@surrey.ac.uk [Telekom Malaysia Research and Development Sdn Bhd., 63000 Cyberjaya, Selangor (Malaysia)

    2015-10-15

    Full text: Using tailor made sub-mm diameter doped-silica fibres, we are carrying out luminescence dosimetry studies for a range of situations, including thermoluminescence (Tl)investigations on a liquid alpha source formed of {sup 223}RaCl (the basis of the Bayer Health care product Xofigo), the Tl response to a 62 MeV proton source and Tl response to irradiation from an {sup 241}Am-Be neutron source. In regard to the former, in accord with the intrinsic high linear energy transfer (Let) and short path length (<100 um) of the α-particles in calcified tissue, the product is in part intended as a bone-seeking radionuclide for treatment of metastatic cancer, offering high specificity and efficacy. The Tl yield of Ge-doped SiO{sub 2} fibres has been investigated including for photonic crystal fibre un collapsed, flat fibres and single mode fibres, these systems offering many advantages over conventional passive dosimetry types. In particular, one can mention comparable and even superior sensitivity, an effective atomic number Z{sub eff} of the silica dosimetric material close to that of bone, and the glassy nature of the fibres offering the additional advantage of being able to place such dosimeters directly into liquid environments. Finally we review the use of our tailor made fibres for on-line radioluminescence measurements of radiotherapy beams. The outcome from these various lines of research is expected to inform development of doped fiber radiation dosimeters of versatile utility, ranging from clinical applications through to industrial studies and environmental evaluations. (Author)

  11. Blood proteins as carcinogen dosimeters

    International Nuclear Information System (INIS)

    Tannenbaum, S.R.; Skipper, P.L.

    1986-01-01

    The problem of quantifying exposure to genotoxins in a given individual represents a formidable challenge. In this paper methods which rely on the covalent binding of carcinogens and their metabolites to blood proteins are described. That carcinogens interact with proteins as well as with DNA has been established, although whether protein-carcinogen adducts can result in genetic damage has not been established. It has been shown, however, that the amount of a protein carcinogen adduct formed may be used as a quantitative measure of exposure to a carcinogen. Such a measure presumably is reflective of the absorption, metabolism, and excretion of the compound in an exposed individual. Protein adduction may reflect exposure in a time-frame of weeks to months. Thus, protein adduct measurement is a form of human chemical dosimetry. Hemoglobin and albumin are promising candidates for such dosimeters. Hemoglobin has a lifetime of about 120 days in humans; thus, circulating levels of carcinogen-modified hemoglobin will reflect the level of carcinogen exposure during a period of nearly four months. It also possesses some metabolic competence, particularly, the ability to oxidize aromatic hydroxylamines to nitroso compounds which react quite efficiently with sulfhydryl groups. Albumin has a half-life of 20 to 25 days in man. This protein does not possess metabolic capacity other than, perhaps, some esterase activity. In contrast to hemoglobin, though, it is not protected by the erythrocyte membrane and might be the target for a greater number of carcinogens. It is present and is synthesized in the same cells in which the reactive metabolic intermediates of carcinogens are mostly formed - the hepatocytes. Also, albumin has a number of high-affinity binding sites for a broad spectrum of xenobiotics and endobiotics. 25 refs., 1 tab

  12. RDM lifetime measurements in 187Tl

    International Nuclear Information System (INIS)

    Chamoli, S.K.; Joshi, P.; Kumar, A.; Govil, I.M.; Mukherjee, G.; Singh, R.P.; Muralithar, S.; Bhowmik, R.K.

    2003-01-01

    The present work is an attempt to study the shape changes in 187 Tl through a measurement of electromagnetic transition probabilities of the high spin states. The Doppler shifted recoil distance technique was used to measure the lifetimes

  13. Disquisition and technical alteration about TL apparatus

    International Nuclear Information System (INIS)

    Wang Guangxiang; Li Mingliang

    2002-01-01

    The author simply introduces the disadvantage of TL apparatus controlled by single chip. The project uses the PC computer to replace single chip control. So it must be changed the interface and made up a software with Chinese

  14. Progress and problems with automated TL dating

    International Nuclear Information System (INIS)

    McKerrell, H.; Mejdahl, V.

    1981-01-01

    A number of basic problems connected with the measurement of beta and gamma dose-rates are discussed, and the possibility of using low-temperature peaks in quartz and feldspar for dose-rate measurements is examined. Preliminary results of TL measurements on individual grains of quartz and feldspar are presented. A TL dating method based on the difference in the archaeological dose received by potassium feldspar and quartz grains is proposed. (author)

  15. Water equivalence of polymer gel dosimeters

    International Nuclear Information System (INIS)

    Sellakumar, P.; James Jebaseelan Samuel, E.; Supe, Sanjay S.

    2007-01-01

    To evaluate the water equivalence and radiation transport properties of polymer gel dosimeters over the wide range of photon and electron energies 14 different types of polymer gels were considered. Their water equivalence was evaluated in terms of effective atomic number (Z eff ), electron density (ρ e ), photon mass attenuation coefficient (μ/ρ), photon mass energy absorption coefficient (μ en /ρ) and total stopping power (S/ρ) tot of electrons using the XCOM and the ESTAR database. The study showed that the effective atomic number of polymer gels were very close ( en /ρ for all polymer gels were in close agreement ( tot of electrons in polymer gel dosimeters were within 1% agreement with that of water. From the study we conclude that at lower energy (<80keV) the polymer gel dosimeters cannot be considered water equivalent and study has to be carried out before using the polymer gel for clinical application

  16. Diffusion measurement in ferrous infused gel dosimeters

    International Nuclear Information System (INIS)

    Zahmatkesh, M. H.; Healy, B. J.

    2003-01-01

    Background: The compositions of Ferrous sulphate, Agarose and Xylenol orange dye and Ferrous sulphate, Gelatin and Xylenol orange dye in solution of distilled water and sulphuric acid are two tissue-equivalent gel dosimeters. Ionizing radiation causes oxidation of Fe 2+ ion to Fe 3+ ions which diffuse through the gel matrix and blur the image of absorbed dose over a period of hours after irradiation. Materials and methods: 25 m M sulphuric acid, 0.4 mm ferrous ammonium sulphate, 0.2 mm xylenol orange dye and 1% by weight agarose in distilled water named Agarose and Xylenol orange dye and 0.1 mm ferrous ammonium sulphate, 0.1 mm xylenol orange dye, 50 mm sulphuric acid and 5% by weight gelatin in distilled water named Gelatin and Xylenol orange dye are used as two gel dosimeters. All chemicals were supplied by Sigma Ald ridge Company, Germany. The gels were poured in Perspex casts and were irradiated to a beam of X ray from linear accelerators or X ray machine. Results: In this study diffusion coefficients of Agarose and Xylenol orange dye and Gelatin and Xylenol orange dye dosimeters have been measured through a computer program for different temperature. The ferric ion diffusion coefficient (D) for the Agarose and Xylenol orange dye and Gelatin and Xylenol orange dye dosimeters were measured as (1.19.±0.03) x 10 -2 cm 2 .hr -1 and (0.83±0.03) x 10 -2 cm 2 .hr -1 respectively at room temperature. Conclusion: For both dosimeters the diffusion coefficients decreased with gel storage temperatures down to 6 d ig C . Gelatin and Xylenol orange dye dosimeters have advantage of lower diffusion coefficient for a specified temperature

  17. Research on the formula of radiochromic film dosimeters

    International Nuclear Information System (INIS)

    Li Huazhi; Xiao Zhenhong; Lin Min; Cui Ying; Chen Kesheng; Chen Yundong; Ye Hongsheng; Lin Jingwen

    2006-10-01

    The formula of radiochromic film dosimeters was studied. Commercially available nylon was used as the matrix, while hexahydroxyethyl pararosaniline cyanide (HPR-CN) and pararosaniline cyanide (PR-CN) that are made in China and other countries were used as the dyes of the dosimeters. the performance of the thin film dosimeters made in CIAE was tested and compared with each other. The formula of the dosimeters was finally confirmed by testing its physical properties and dosimetric characteristics. (authors)

  18. Development and evaluation of dosimeters from locally available perspex for high dose measurement in industrial radiation processing. Final report for the period December 1985 - December 1989

    International Nuclear Information System (INIS)

    Amin, R.

    1989-11-01

    The objective of the study was to find, develop and evaluate suitable low cost perspex materials to be used as routine dosemeters for high dose measurements, particularly in industrial radiation processing. Red, amber and white perspex materials of local origin were investigated for their dosimetric properties and evaluated against Harwell red perspex, Fricke and ethanol-monochlorobenzene dosemeters. 5 refs, 13 figs, 5 tabs

  19. Development and evaluation of dosimeters from locally available perspex for high dose measurement in industrial radiation processing. Final report for the period December 1985 - December 1989

    Energy Technology Data Exchange (ETDEWEB)

    Amin, R [Atomic Energy Research Establishment, Dhaka (Bangladesh). Inst. of Food and Radiation Biology

    1989-11-01

    The objective of the study was to find, develop and evaluate suitable low cost perspex materials to be used as routine dosemeters for high dose measurements, particularly in industrial radiation processing. Red, amber and white perspex materials of local origin were investigated for their dosimetric properties and evaluated against Harwell red perspex, Fricke and ethanol-monochlorobenzene dosemeters. 5 refs, 13 figs, 5 tabs.

  20. The use of thallium diethyldithiocarbamate for mapping CNS potassium metabolism and neuronal activity: Tl+ -redistribution, Tl+ -kinetics and Tl+ -equilibrium distribution.

    Science.gov (United States)

    Wanger, Tim; Scheich, Henning; Ohl, Frank W; Goldschmidt, Jürgen

    2012-07-01

    The potassium (K(+)) analogue thallium (Tl(+)) can be used as a tracer for mapping neuronal activity. However, because of the poor blood-brain barrier (BBB) K(+) -permeability, only minute amounts of Tl(+) enter the brain after systemic injection of Tl(+) -salts like thallium acetate (TlAc). We have recently shown that it is possible to overcome this limitation by injecting animals with the lipophilic chelate complex thallium diethyldithiocarbamate (TlDDC), that crosses the BBB and releases Tl(+) prior to neuronal or glial uptake. TlDDC can thus be used for mapping CNS K(+) metabolism and neuronal activity. Here, we analyze Tl(+) -kinetics in the rodent brain both experimentally and using simple mathematical models. We systemically injected animals either with TlAc or with TlDDC. Using an autometallographic method we mapped the brain Tl(+) -distribution at various time points after injection. We show that the patterns and kinetics of Tl(+) -redistribution in the brain are essentially the same irrespective of whether animals have been injected with TlAc or TlDDC. Data from modeling and experiments indicate that transmembrane Tl(+) -fluxes in cells within the CNS in vivo equilibrate at similar rates as K(+) -fluxes in vitro. This equilibration is much faster than and largely independent of the equilibration of Tl(+) -fluxes across the BBB. The study provides further proof-of-concept for the use of TlDDC for mapping neuronal activity and CNS K(+) -metabolism. A theoretical guideline is given for the use of K(+) -analogues for imaging neuronal activity with general implications for the use of metal ions in neuroimaging. © 2012 The Authors. Journal of Neurochemistry © 2012 International Society for Neurochemistry.

  1. The effect of heat treatment on the thermoluminescence of naturally-occurring calcites and their use as a gamma-ray dosimeter

    International Nuclear Information System (INIS)

    Engin, Birol; Gueven, Olgun

    2000-01-01

    The feasibility of using naturally-occurring calcite for gamma-ray dosimetry was investigated. Anneal treatment above 350 deg. C increased the sensitivity of all radiation-induced TL peaks except the glow peaks above 300 deg. C. On the other hand, annealing in air, at a temperature of 700 deg. C caused a collapse in the TL sensitivity. The increase in TL efficiency was found to depend on the annealing temperature and time. Heating at 600 deg. C for 5 h and quenching in ambient air are the optimum conditions for TL sensitivity enhancement in the calcite materials investigated. These results are explained using the energy scheme of the pre-dose model of and in terms of the impurity rearrangements in the crystal lattice induced by heating. It was found that the values of the kinetic parameters E, s and b for TL glow peaks remained unchanged for annealed samples. The TL dose-response curves for stable dosimetric peaks of annealed and unannealed calcite samples could be fitted to the same linear mathematical function. This implies that the annealing process probably does not change the nature of the trapping centers except the low temperature TL peaks at 125 and 160 deg. C of flowstone. The TL dosimetric parameters of calcite samples annealed, including glow curves, fading characteristics, dose-responses, dose-rate responses and energy responses, have also been studied in detail. The response to gamma-rays of annealed calcite samples was found to be linear from 0.05 to 10 4 Gy. The lower limit of observable doses for each calcite sample was about 0.05 Gy. This offers the possibility of applying the investigated materials for gamma-ray dosimetry within this useful range. These dosimeters can be used in various applications, such as, in industries related to chemical technology (polymerization), food processing and in determining the dose received by the patient during medical examination and treatment

  2. Investigating hydrogel dosimeter decomposition by chemical methods

    International Nuclear Information System (INIS)

    Jordan, Kevin

    2015-01-01

    The chemical oxidative decomposition of leucocrystal violet micelle hydrogel dosimeters was investigated using the reaction of ferrous ions with hydrogen peroxide or sodium bicarbonate with hydrogen peroxide. The second reaction is more effective at dye decomposition in gelatin hydrogels. Additional chemical analysis is required to determine the decomposition products

  3. Response characteristics of selected personnel neutron dosimeters

    International Nuclear Information System (INIS)

    McDonald, J.C.; Fix, J.J.; Hadley, R.T.; Holbrook, K.L.; Yoder, R.C.; Roberson, P.L.; Endres, G.W.R.; Nichols, L.L.; Schwartz, R.B.

    1983-09-01

    Performance characteristics of selected personnel neutron dosimeters in current use at Department of Energy (DOE) facilities were determined from their evaluation of neutron dose equivalent received after irradiations with specific neutron sources at either the National Bureau of Standards (NBS) or the Pacific Northwest Laboratory (PNL). The characteristics assessed included: lower detection level, energy response, precision and accuracy. It was found that when all of the laboratories employed a common set of calibrations, the overall accuracy was approximately +-20%, which is within uncertainty expected for these dosimeters. For doses above 80 mrem, the accuracy improved to better than 10% when a common calibration was used. Individual differences found in this study may reflect differences in calibration technique rather than differences in the dose rates of actual calibration standards. Second, at dose rates above 100 mrem, the precision for the best participants was generally below +-10% which is also within expected limits for these types of dosimeters. The poorest results had a standard deviation of about +-25%. At the lowest doses, which were sometimes below the lower detection limit, the precision often approached or exceeded +-100%. Third, the lower level of detection for free field 252 Cf neutrons generally ranged between 20 and 50 mrem. Fourth, the energy dependence study provided a characterization of the response of the dosimeters to neutron energies far from the calibration energy. 11 references, 22 figures, 26 tables

  4. Silicon Diode Dosimeter for Fast Neutrons

    International Nuclear Information System (INIS)

    Svansson, L.; Widell, C.O.; Swedberg, P.; Wik, M.

    1968-11-01

    The change of the current-voltage characteristics of a small silicon diode is used as a measure of fast neutron dose in the Fast Neutron Dosimeter 5422. This change is permanent and therefore it is possible to integrate doses over a long period of time. Doses from some rad up to 1000 rad can be measured and the information stored is not destroyed during readout. Considerable research work in this field has previously been carried out by the Swedish Institute for National Defence in collaboration with the Institute of Semiconductor Research Stockholm. The present investigation has been made in order to establish the possibilities of the dosimeter for practical applications and to study the variations of important parameters as a function of the production process. In particular the following parameters have been studied: - dose sensitivity, - energy dependence; - fading effect; - temperature influence; - maximum measurable dose. In general one might conclude that the dosimeter 5422 well fulfills requirements usually specified for a dosimeter for field service. Temperature influence and fading effect are of little practical importance within the recommended range of measurement

  5. Silicon Diode Dosimeter for Fast Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Svansson, L; Widell, C O; Swedberg, P [The Inst. of Semiconductor Researc h, Stockholm (Sweden); Wik, M [The Swedish Institute for National Defence, Sun dbyberg (Sweden)

    1968-11-15

    The change of the current-voltage characteristics of a small silicon diode is used as a measure of fast neutron dose in the Fast Neutron Dosimeter 5422. This change is permanent and therefore it is possible to integrate doses over a long period of time. Doses from some rad up to 1000 rad can be measured and the information stored is not destroyed during readout. Considerable research work in this field has previously been carried out by the Swedish Institute for National Defence in collaboration with the Institute of Semiconductor Research Stockholm. The present investigation has been made in order to establish the possibilities of the dosimeter for practical applications and to study the variations of important parameters as a function of the production process. In particular the following parameters have been studied: - dose sensitivity, - energy dependence; - fading effect; - temperature influence; - maximum measurable dose. In general one might conclude that the dosimeter 5422 well fulfills requirements usually specified for a dosimeter for field service. Temperature influence and fading effect are of little practical importance within the recommended range of measurement.

  6. Compton effect thermally activated depolarization dosimeter

    Science.gov (United States)

    Moran, Paul R.

    1978-01-01

    A dosimetry technique for high-energy gamma radiation or X-radiation employs the Compton effect in conjunction with radiation-induced thermally activated depolarization phenomena. A dielectric material is disposed between two electrodes which are electrically short circuited to produce a dosimeter which is then exposed to the gamma or X radiation. The gamma or X-radiation impinging on the dosimeter interacts with the dielectric material directly or with the metal composing the electrode to produce Compton electrons which are emitted preferentially in the direction in which the radiation was traveling. A portion of these electrons becomes trapped in the dielectric material, consequently inducing a stable electrical polarization in the dielectric material. Subsequent heating of the exposed dosimeter to the point of onset of ionic conductivity with the electrodes still shorted through an ammeter causes the dielectric material to depolarize, and the depolarization signal so emitted can be measured and is proportional to the dose of radiation received by the dosimeter.

  7. Single and multichannel scintillating fiber dosimeter for radiotherapic beams with SiPM readout

    Energy Technology Data Exchange (ETDEWEB)

    Berra, A., E-mail: alessandro.berra@gmail.it [Università degli Studi dell' Insubria e INFN sezione di Milano Bicocca (Italy); Ferri, A. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (Italy); Novati, C. [Università degli Studi dell' Insubria e INFN sezione di Milano Bicocca (Italy); Ostinelli, A. [Ospedale Sant' Anna, Servizio di Fisica Sanitaria (Italy); Paternoster, G.; Piemonte, C. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (Italy); Prest, M. [Università degli Studi dell' Insubria e INFN sezione di Milano Bicocca (Italy); Vallazza, E. [INFN Sezione di Trieste (Italy)

    2016-12-01

    The treatment of many neoplastic diseases requires the use of radiotherapy, which consists in the irradiation of the tumor, identified as the target volume, with ionizing radiations generated both by administered radiopharmaceuticals or by linear particle accelerators (LINACs). The radiotherapy beam delivered to the patient must be regularly checked to assure the best tumor control probability: this task is performed with dosimeters, i.e. devices able to provide a measurement of the dose deposited in their sensitive volume. This paper describes the development of two scintillator dosimeter prototypes for radiotherapic applications based on plastic scintillating fibers read out by high dynamic range Silicon PhotoMultipliers. The first dosimeter, consisting of a single-channel prototype with a pair of optical fibers, a scintillating and a white one, read out by two SiPMs, has been fully characterized and led to the development of a second multi-channel dosimeter based on an array of scintillating fibers: this device represents the first step towards the assembly of a “one-shot” device, capable to perform some of the daily quality controls in a few seconds. The dosimeters characterization was performed with a Varian Clinac iX linear accelerator at the Radiotherapy Department of the St. Anna Hospital in Como (IT).

  8. Clinical dosimeter based on diamond detector

    International Nuclear Information System (INIS)

    Chervjakov, A.M.; Ljalina, L.I.; Ljutina, G.J.; Khrunov, V.S.; Martynov, S.S.; Popov, S.A.

    2002-01-01

    Full text: Diamond detectors have found application in the relative dosimetry and their parameters have been described elsewhere. Today, the exclusive producer of the diamond detector is the Institute of Physical and Technical Problems, Russia, and exclusive dealer is the PTW-Freiburg. The main features of the diamond detector are good long time stability, suitable range of the energy dependence for photon and electron beams in clinical use, independence of the measured date from temperature and pressure. The high sensitivity per volume unit of the diamond detector (1500 times higher than ionization chamber) allowed using detectors with very small volume (1-5 mm 3 ) and rather simple electronics for ionization current registration. The new dosimeter consists of the diamond detector itself, 40 m registration cable, pre-amplifier, micro-processor block for data handling and absorbed dose calculation using the calibration factor of diamond detector in terms of absorbed dose to water. Dosimeter has the possibility to work with PC using standard RS-232 interface. The main features of the dosimeter are as follows: the range of dose rate measurements for photon, electron and proton beams is within 0.01-1.0 Gy/s; the energy ranges for photons are 0.08-25 MeV, and 4-25 MeV for electrons, with energy dependence no more than ±2%; the main uncertainty of the dose measurements is within ±2%; the pre-irradiation dose for diamond detector is no more than 10 Gy; the sensitive volume of the used diamond detectors is within 1-5 mm 3 ; the weight of the dosimeter no more than 2 kg. The new dosimeter was evaluated at the Central Research Institute of Roentgenology and Radiology, St. Petersburg, Russia to verify its performance. The dosimeter was used as a reference instrument for dose measurements at Cobalt-60 unit, SL75-5 and SL-20 linear accelerators and the test results have shown that the device have met the specifications. It is planned to produce dosimeter as serial device by

  9. NaI(Tl) electron energy resolution

    CERN Document Server

    Mengesha, W

    2002-01-01

    NaI(Tl) electron energy resolution eta sub e was measured using the Modified Compton Coincidence Technique (MCCT). The MCCT allowed detection of nearly monoenergetic internal electrons resulting from the scattering of incident 662 keV gamma rays within a primary NaI(Tl) detector. Scattered gamma rays were detected using a secondary HPGe detector in a coincidence mode. Measurements were carried out for electron energies ranging from 16 to 438 keV, by varying the scattering angle. Measured HPGe coincidence spectra were deconvolved to determine the scattered energy spectra from the NaI(Tl) detector. Subsequently, the NaI(Tl) electron energy spectra were determined by subtracting the energy of scattered spectra from the incident source energy (662 keV). Using chi-squared minimization, iterative deconvolution of the internal electron energy spectra from the measured NaI(Tl) spectra was then used to determine eta sub e at the electron energy of interest. eta sub e values determined using this technique represent va...

  10. Role of gel dosimeters in boron neutron capture therapy

    International Nuclear Information System (INIS)

    Khajeali, Azim; Farajollahi, Ali Reza; Khodadadi, Roghayeh; Kasesaz, Yaser; Khalili, Assef

    2015-01-01

    Gel dosimeters have acquired a unique status in radiotherapy, especially with the advent of the new techniques in which there is a need for three-dimensional dose measurement with high spatial resolution. One of the techniques in which the use of gel dosimeters has drawn the attention of the researchers is the boron neutron capture therapy. Exploring the history of gel dosimeters, this paper sets out to study their role in the boron neutron capture therapy dosimetric process. - Highlights: • Gel dosimeters have been investigated. • Conventional dosimetric proses of BNCT has been investigated. • Role of gel dosimeters in BNCT has been investigated

  11. Directional Radiation Dosimeter for Area and Environmental Monitoring

    International Nuclear Information System (INIS)

    Manzoli, J.E.; Campos, V.P.; Moura, E.S.

    2009-01-01

    It is presented a dosimeter that is able to measure the photon exposure and the direction from where the radiation came from. Preliminary measurements performed by this new directional radiation dosimeter demonstrate its application. This dosimeter consists of a small lead cube with thermoluminescent discs on each face, placed in well known coordinates. Only one dosimeter of this kind indicates the direction of the radiation beam, if it came from a unique position. This study was conducted inside the radiation room of a Cobalt-60 Gamma Irradiator and the dosimeter indicated the source position

  12. Dental tissue as a thermoluminescence dosimetry dosimeter

    International Nuclear Information System (INIS)

    Solaimani, F.; Zahmatkesh, M.H.; Akhlaghpoor, Sh.

    2003-01-01

    Background: Thermoluminescence dosimetry is one of the dosimetry procedures used widely as routine and personal dosimeters. In order to extend this kind of dosimeters, dental tissue has been examined and was found promising as a Thermoluminescence Dosimetry dosimeter. Materials and Methods: In this study, 70 health teeth were collected. The only criterion, wich was considered for selection of the teeth, was the healthiness of them regardless of age and gender of the donors. All collected samples were washed and cleaned and milled uniformly. The final powder had a uniform grain size between 100-300 micrometer. The sample was divided into four groups. Group A and B were used for measurement of density and investigation of variation of thermoluminescent characteristics with temperature respectively. Groups C and D were used for investigation of variation of thermoluminescent intensity with dose and fading of this intensity with time. In all cases the results obtained with dental tissue were compared to a standard LiF, thermoluminescence dosimetry dosimeter. Results: It was found that, average density of the dental tissue was 1.570 g/cm 3 , which is comparable to density of LiF, which is 1.612g/cm 3 . It was also concluded that the range of 0-300 d ig C , dental tissue has a simple curve with two specific peaks at 140 and 25 d ig C respectively. The experiment also showed that, the variation of relative intensity versus dose is linear in the range of 0.04-0.1 Gy. The fading rate of dental tissue is higher than LiF but still in the acceptable range (14% per month in compare to 5.2% per month). Conclusion: Dental tissue as a natural dosimeter is comparable with Thermoluminescence Dosimetry and can be used in accidental events with a good approximation

  13. Tl response of LiF:Mg, Cu, P + PTFE to Am-Be neutrons

    International Nuclear Information System (INIS)

    Gonzalez M, P.R.

    2000-01-01

    In different laboratories of the world it is followed the research about development of new Tl materials, whose main characteristics should be their equivalence with the tissue and their high sensibility to any type of radiation. The study consists in to measure the Tl peak intensity which TLD-100 presents at being irradiated with neutrons and that appears over 250 Centigrade, for compare it with the Tl intensity of the LiF: Mg, Cu, P + PTFE dosemeters. However, not all dosemeters of the same group show the interesting peak, by this only can be the total Tl intensity of dosemeters studied. In the ININ dosemeters development laboratory, we have developed a Tl material of lithium fluoride activated with magnesium, copper and phosphorus (LiF: Mg, Cu, P) that in polycrystalline powder form is almost 35 times more sensitive than the TLD-100 commercial dosemeter of Harshaw/Filtrol, USA. With the use of polytetrafluorethylene (PTFE) and with the above described Tl material, it has been possible to obtain dosemeters in pellet form of LiF: Mg, Cu, P + PTFE. (Author)

  14. Guide for the implementation in external radiation therapy of quality insurance by in vivo measurements by thermoluminescent dosimeters and semi-conductors. S.F.P.M. report nr 18-2000

    International Nuclear Information System (INIS)

    Goyet, Dominique; Dusserre, Andree; Marcie, Serge; Telenczak, Pascale; Waultier, Serge; Costa, Andre; Lisbona, Albert; Noel, Alain

    2000-01-01

    This report aims at gathering all necessary information for the implementation of treatment quality insurance procedures by in vivo measurements in the case of external radiation therapy. It presents the different techniques, describes characteristics of TL meters, electro-meters, TL dosimeters, and semi-conductors currently available on the French market, and indicates all accessories required by these techniques. It also recalls principles of in vivo measurements, as well as calibration procedures. The last part proposes a description of acceptance and quality control procedures for these equipment

  15. TL process in europium doped alkaline earth sulphate phosphors- a review

    International Nuclear Information System (INIS)

    Bhatt, B.C.

    2003-01-01

    CaSO 4 doped with the rare earth (RE) ion dysprosium or thulium is used routinely as a thermoluminescent dosimeter (TLD) to monitor personal exposure to x- and γ-radiation. The CaSO 4 :Eu phosphor is potentially important for radio photoluminescence (RPL) and ultraviolet (UV) dosimetry. Eu 3+ → Eu 2+ conversion is suggested to play a pivotal role in UV and γ-ray induced thermoluminescence. However, there is disagreement among different workers on the mechanism of gamma and UV induced TL in this phosphor system. This paper will review the work reported on CaSO 4 :Eu and make effects to project overall picture on this phosphor system. (author)

  16. 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.

  17. 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

  18. Kinetic Modeling of the Lif:Mg,Ti TL System including Defect Creation: Implications to, and Development of Track Structure Theory Calculations of Heavy Charged Particle Radiation Effects

    International Nuclear Information System (INIS)

    Eliyahu, Ian

    2015-01-01

    In this research, various kinetic models were developed for LiF:Mg,Ti crystals, both in the irradiation and recombination stages. The models were later used to improve on track structure theory, which attempts to describe radiation effects of Heavy charged particle. To achieve this goal, the research focused on three main areas of endeavor. 1. In the first experimental measurements of optical absorption on LiF:Mg,Ti following low ionization density radiation (photons) and high ionization density protons and He ions were carried out in order to investigate the degree of applicability of track structure theory to the prediction of heavy charged particle induced effects of radiation. These measurements are described below. a) Photon induced optical absorption (OA) dose response was measured over an extended dose-range from 10 Gy to 105 Gy for the main OA bands in LiF:Mg,Ti, i.e., the 4.0 eV band (trapping center associated with glow peak 5 in the thermoluminescence glow curve), 4.77 eV band , 5.08 eV (F band) and 5.45 eV band. The extended dose-range allowed the unambiguous determination of linear/exponentially saturation behavior for all the OA bands. For the two main OA bands of interest at 4.0 eV and 5.08 eV, the dose filling factor was determined to be 5 ± 0.6.10-4 Gy-1 and 6.1 ± 0.4 × 10-5 Gy-1 respectively. The surprising, previously unexplained, linear/exponentially saturating dose response of the F band even though vacancies/F centers are being created by the radiation was explained in a kinetic analysis also described in the following. b) Heavy charged particle (HCP) optical absorption was carried out for 1.4 MeV protons and 4 MeV He ions at the SARAF, RARAF and BINA accelerators. Fluence response was measured over the extended range from 1010 cm-2 to 2.1014 cm-2. The low fluence region from 1010 cm-2 to 1011 cm-2 in the no-track-overlap regime allows a comparison of the experimental measurements and the track structure theory (TST) evaluations of the

  19. Report on the results of the third intercomparison study of thermoluminescent dosimeters for environmental measurements

    International Nuclear Information System (INIS)

    Driscoll, C.M.H.

    1988-01-01

    Scientific laboratories within the Member States of the European Communities have a continuing interest in the use and development of both thermoluminescent dosimeters and thermoluminescence measurement techniques for the assessment of exposure from environmental gamma radiation. In the United Kingdom, for example, environmental thermoluminescent dosimeters have been developed by the National Radiological Protection Board (NRPB) and used in a national survey of indoor radiation exposure. Other laboratories in various Member States are currently involved in similar studies of natural radiation exposure or are using thermoluminescent dosimeters for environmental measurements at reactor sites. Therefore, it is appropriate that such laboratories have facilities within the European Community for standardization and intercomparison of their environmental measurement techniques

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

    International Nuclear Information System (INIS)

    Silva, Cleber Feijo; Campos, Leticia Lucente

    2013-01-01

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

  1. Redox-Phen solution: A water equivalent dosimeter for UVA, UVB and X-rays radiation

    Science.gov (United States)

    Marini, A.; Ciribolla, C.; Lazzeri, L.; d'Errico, F.

    2018-06-01

    Polysulphone films are the only type of UV passive dosimeters that are widely adopted for research and personal monitoring. Even though many studies concentrated on the development and characterization of these films, they still present some shortcomings. The more important limitations of them are that they can measure only UVB radiations and that they change color at 330 nm, requiring special equipment to read them. To overcome these limitations we developed an aqueous dosimeter that is sensitive to UVA, UVB and X-rays named Redox-Phen solution. This dosimeter is inexpensive and water equivalent, being made of more than 99 wt% of water. It changes color in the visible region upon irradiation, thus it can be measured via simple optical method, and an evaluation of the exposition can be made also by naked eyes.

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

    International Nuclear Information System (INIS)

    Cavinato, Christianne C.; Campos, Leticia L.; Souza, Benedito H.; Carrete Junior, Henrique; Daros, Kellen A.C.; Medeiros, Regina B.; Giordani, Adelmo J.

    2011-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

  4. Desk-top computer assisted processing of thermoluminescent dosimeters

    International Nuclear Information System (INIS)

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

    1977-01-01

    An accurate dosimetric system utilizing a desk-top computer and high sensitivity ribbon type TLDs has been developed. The system incorporates an exposure history file and procedures designed for constant spatial orientation of each dosimeter. Processing of information is performed by two computer programs. The first calculates relative response factors to insure that the corrected response of each TLD is identical following a given dose of radiation. The second program computes a calibration factor and uses it and the relative response factor to determine the actual dose registered by each TLD. (U.K.)

  5. Oscillometric and conductometric analysis of aqueous and organic dosimeter solutions

    DEFF Research Database (Denmark)

    Kovacs, A.; Slezsak, I.; McLaughlin, W.L.

    1995-01-01

    Conductometric and oscillometric evaluation methods have earlier been developed to determine absorbed dose in the ethanol-monochlorobenzene dosimeter solution. Recent investigations on the same solution as well as on alanine solutions included the study of the possible use of different type ''con...... of the applicable concentration of the alanine solute and the dose (1 to 50 kGy) and dose-rate range using both electron (2.6 mu s at 13 mu A to 4 mu s at 1.0 A pulse length and beam current) and gamma radiation (0.13 to 30 kGy h(-1))....

  6. Electrochemically produced alumina as TL detector

    International Nuclear Information System (INIS)

    Osvay, M.

    1996-01-01

    The goal of this work was to compare the TL properties of various electrochemically produced alumina layers (E-AIO) in order to investigate the effect of the electrolyte and the Mg content on the alloys. It has been found that the TL sensitivity of oxidised layers is more influenced by the type of electrolyte, than by the composition of alloy. Hard oxide layer evolved in reduction electrolyte has rather different character compared to other alumina production investigated. The effect of reducing media seems to be very important during preparation of alumina layer. One of the advantages properties of E-AIO is, that it serve a promising method to increase the measuring range of TL method above 10 kGy as well. (author)

  7. Detailed α -decay study of 180Tl

    Science.gov (United States)

    Andel, B.; Andreyev, A. N.; Antalic, S.; Barzakh, A.; Bree, N.; Cocolios, T. E.; Comas, V. F.; Diriken, J.; Elseviers, J.; Fedorov, D. V.; Fedosseev, V. N.; Franchoo, S.; Ghys, L.; Heredia, J. A.; Huyse, M.; Ivanov, O.; Köster, U.; Liberati, V.; Marsh, B. A.; Nishio, K.; Page, R. D.; Patronis, N.; Seliverstov, M. D.; Tsekhanovich, I.; Van den Bergh, P.; Van De Walle, J.; Van Duppen, P.; Venhart, M.; Vermote, S.; Veselský, M.; Wagemans, C.

    2017-11-01

    A detailed α -decay spectroscopy study of 180Tl has been performed at ISOLDE (CERN). Z -selective ionization by the Resonance Ionization Laser Ion Source (RILIS) coupled to mass separation provided a high-purity beam of 180Tl. Fine-structure α decays to excited levels in the daughter 176Au were identified and an α -decay scheme of 180Tl was constructed based on an analysis of α -γ and α -γ -γ coincidences. Multipolarities of several γ -ray transitions deexciting levels in 176Au were determined. Based on the analysis of reduced α -decay widths, it was found that all α decays are hindered, which signifies a change of configuration between the parent and all daughter states.

  8. Provision of dosimeters by official monitoring services for eye lens dose estimation

    International Nuclear Information System (INIS)

    Engelhardt, J.; Martini, E.

    2013-01-01

    Recent epidemiological studies are implying that the radio sensitivity of the eye lens is much higher than supposed in the past. International recommendations and standards demand to lower down the annual limit of the eye lens organ dose to 20 mSv. Since about 10 years German monitoring services offer partial-body dosimeters fixed on the head or on glasses for monitoring the eye lens dose. These dosimeters are optimized to measure the (surface) personal dose equivalent H p (0,07) from 0,5 mSv up to 10 Sv, which clearly overestimate the organ dose of the eye lens. With special features like different calibrations partial-body dosimeters should be applicable for legal dosimetry to avoid the development of special H p (3) dosimeters. Accepting the right way for wearing these dosimeters it is important to get the right results. Practical experiences are shown with measuring results and the difficulties of rounding the exact measuring values to discrete dose steps. Closing this article we point to still missing legal basis and open questions regarding to type testing procedures. (orig.)

  9. A personal radio-frequency dosimeter with cumulative-dose recording capabilities

    International Nuclear Information System (INIS)

    Rochelle, R.W.; Moore, M.R.; Thomas, R.S.; Ewing, P.D.; Hess, R.A.; Hoffheins, B.S.

    1990-01-01

    The radio-frequency (rf) dosimeter developed by the Oak Ridge National Laboratory is a portable, pocket-sized cumulative-dose recording device designed to detect and record the strengths and durations of electric fields present in the work areas of naval vessels. The device measures an integrated dose and records the electric fields that exceed the permissible levels set by the American National Standards Institute. Features of the rf dosimeter include a frequency range of 30 MHz to 10 GHz and a three-dimensional sensor. Data obtained with the rf dosimeter will be used to determine the ambient field-strength profile for shipboard personnel over an extended time. Readings are acquired and averaged over a 6-min period corresponding to the rise time of the core body temperature. These values are stored for up to 6 months, after which the data are transferred to a computer via the dosimeter's serial port. The rf dosimeter should increase knowledge of the levels of electric fields to which individuals are exposed. 13 refs., 16 figs., 2 tabs

  10. TL dosimetry for quality control of CR mammography imaging systems

    Science.gov (United States)

    Gaona, E.; Nieto, J. A.; Góngora, J. A. I. D.; Arreola, M.; Enríquez, J. G. F.

    The aim of this work is to estimate the average glandular dose with thermoluminescent (TL) dosimetry and comparison with quality imaging in computed radiography (CR) mammography. For a measuring dose, the Food and Drug Administration (FDA) and the American College of Radiology (ACR) use a phantom, so that dose and image quality are assessed with the same test object. The mammography is a radiological image to visualize early biological manifestations of breast cancer. Digital systems have two types of image-capturing devices, full field digital mammography (FFDM) and CR mammography. In Mexico, there are several CR mammography systems in clinical use, but only one system has been approved for use by the FDA. Mammography CR uses a photostimulable phosphor detector (PSP) system. Most CR plates are made of 85% BaFBr and 15% BaFI doped with europium (Eu) commonly called barium flourohalideE We carry out an exploratory survey of six CR mammography units from three different manufacturers and six dedicated X-ray mammography units with fully automatic exposure. The results show three CR mammography units (50%) have a dose greater than 3.0 mGy without demonstrating improved image quality. The differences between doses averages from TLD system and dosimeter with ionization chamber are less than 10%. TLD system is a good option for average glandular dose measurement for X-rays with a HVL (0.35-0.38 mmAl) and kVp (24-26) used in quality control procedures with ACR Mammography Accreditation Phantom.

  11. Modelling the behaviour of the push-pull gel dosimeter

    International Nuclear Information System (INIS)

    Bosi, S.G.; Davies, J.B.; Gorjiara, T.; Baldock, C.

    2010-01-01

    Full text: Recent development of a gel dosimeter based on the radiobleaching pigment, genipin, allows development of a new 3D optically scanned gel dosimeter-the p ush-pull g el. This gel would contain two spectrally complementary pigments, one which darkens with dose and another (e.g. genipin) which bleaches. The two pigments deal separately with the high and low dose ends of the dosimeter's dynamic range. The bleaching pigment would be optimised for high sensitivity and the darkening pigment for low. Employing dual pigments, optimised independently, relaxes the need for compromise between sensitivity at low dose and accuracy at high dose. Such a gel, after exposure, would be read using two successive optical CT scans, at two different wavelengths. The reduction in sensitivity of the darkening pigment (allowed by the use of push-pull) would reduce the occurrence of regions of high optical attenuation which can generate optical CT artefacts. Simulated optical CT reconstructions of the optical density map (Fig. La) scanned at the darkening pigment wavelength of a hypothetical push-pull gel, confirms the reduction in susceptibility to artefacts. Fig. I b shows a profile through the map with no stray light added. The centre of the profile in Fig. I d shows a cupping artefact produced by 10 ppm of stray light. The similarity of Fig. Ic and b show that a 30% sensitivity reduction allowed by push-pull, renders the artefact negligible. This paper presents the results of' these simulations of a push-pull gel scanned using optical CT and also some results of experiments with genipin gel. (author)

  12. Experimental Validation of Ex-Vessel Neutron Spectrum by Means of Dosimeter Materials Activation Method

    Directory of Open Access Journals (Sweden)

    S.A. Santa

    2017-06-01

    Full Text Available Neutron spectrum information in reactor core and around of ex-vessel reactor needs to be known with a certain degree of accuracy to support the development of fuels, materials, and other components. The most common method to determine neutron spectra is by utilizing the radioactivation of dosimeter materials. This report presents the evaluation of neutron flux incident on M3dosimeter sets which were irradiated outside the reactor vessel,as well as the validation of  neutron spectrum calculation. Al capsules containing both dosimeter set covered withCd and dosimeter set without Cd cover have been irradiated during the 35th operational cycle in the M3 ex-vessel irradiation hole position207 cmfrom core centerline at the space between the reactor vessel and the safety vessel. The capsules were positioned at Z=0.0 cm of core midplane. Each dosimeter set consists of Co-Al, Sc, Fe, Np, Nb, Ni, B, and Ta. The gamma-ray spectra of irradiated dosimeter materials were measured by 63 cc HPGe solid-state detector and photo-peak spectra were analyzed using BOB75 code. The reaction rates of each dosimeter materials and its uncertainty were analyzed based on 59Co (n,g 60Co, 237Np (n,f 95Zr-103Ru,  45Sc (n,g 46Sc, 58Fe (n,g 59Fe, 181Ta (n,g 182Ta, and 58Ni (n,p58Co reactions. The measured Cd ratios indicate that neutron spectrum at the irradiated dosimeter sets was dominated by low energy neutron. The experimental result shows that the calculated neutron spectra by DORT code at the ex-vessel positions need correction, especially in the fast neutron energy region, so as to obtain reasonable unfolding result consistent with the reaction rate measurement without any exception. Using biased DORT initial spectrum, the neutron spectrum and its integral quantity were unfolded by NEUPAC code. The result shows that total neutron flux, flux above 1.0 MeV, flux above 0.1 MeV, and the displacement rate of the dosimeter set not covered with Cd were 1.75× 1012 n cm2 s-1, 1

  13. Energy-dependency correction factors for the digital dosimeters using in NMD environment dose assessment

    International Nuclear Information System (INIS)

    Lai, Y.C.; Huang, Y. F.; Chen, Y.W.

    2008-01-01

    Full text: Short-term environment dose-rate assessments using real-time digital dosimeters within a Nuclear Medicine Department (NMD) are gaining more world-wide uses recently. In the past, conventional ion chamber-type survey-meters are used dominantly in environmental dose rates evaluation. Although it has suffered less gamma energy-dependency, but it is less sensitive in comparison with other digital dosimeters and more bulky in design that can hardly make it into a pocket size application. With modern electronic advancement and its shrinking in physical size, real-time personal dosimeter nowadays has gaining more popular to use a miniature G-M counter or a solid-state diode sensor, or even a NaI(Tl) scintillation device for ambient radiation monitoring. Radiation sensor operated in pulse-mode can never been used in doses or dose rates determination since each digital pulse has carried no energy information of the impinging gamma ray being interactive with, especially in the G-M counter or the diode sensor case. The raw count rates measured from a pulse-mode device are heavily dependent on the packaging of the sensor to make it less energy-sensitive. The doses or dose rates are then calculated by using a built-in conversion factor, based on a Cs-137 beam source calibration data conducted by various manufacturing vendors, to convert its raw counts into a so-called dose or dose-rate unit. In this study, we have focused our interests in the low energy response of the digital dosimeters from several brands currently for our in-house uses. Mainly, Tc-99m and I-131 in point sources and water phantoms detection configurations have been deployed to simulate our NMD outpatients for environment radiation monitoring purpose. The energy-dependent correction factors of the digital dosimeters will be evaluated by using calibrated Tc-99m or I-131 standard sources directly that has much lower gamma energy than the Cs-137 beam source of 661 keV. In the near future, we would

  14. Comparison of alanine dosimeters using silicone as their binder to a commercial, polystyrene-bound, alanine dosimeter

    International Nuclear Information System (INIS)

    Galindo, S.; Urena-Nunez, F.

    1997-01-01

    The feasibility of practical boron-containing alanine ESR dosimeters for gamma-neutron mixed field irradiation dosimeters depends in part on whether the γ response characteristics of these silicone-bound dosimeters are comparable to those of a commercially available dosimeter that has been used by the International Atomic Energy Agency (International Dose Assurance Service) as a transfer reference dosimeter. This work presents the results of the comparison of 3 batches of silicone-bound alanine dosimeters. The first batch consists of a mixture of alanine and boric acid; the second, alanine and borax; and the last contains only alanine. Results indicate that γ response characteristics of the silicone-bound samples are comparable to those of the commercial, polystyrene-bound, alanine dosimeter and that silicone has a strong potential as a binding substance for alanine ESR dosimetry. (Author)

  15. Application of estimating effective dose from external radiation using two dosimeters during maintenance periods at KNPPS

    International Nuclear Information System (INIS)

    Kim, Hee Geun; Kong, Tae Young

    2008-01-01

    The application of a two-dosimeter and its algorithm and a test of its use in an inhomogeneous high radiation field are described. The goal was to develop an improved method for estimating the effective dose during maintenance periods at Korean nuclear power plants (NPPs). The use of the method in domestic and international NPPs including USA, Canada and Japan was also investigated. The algorithms used by the Canadian Ontario Power Generation (OPG) and American ANSI HPS N13.41, Lakshmanan, NCRP, EPRI and Texas A and M University were extensively analyzed as two-dosimeter algorithms. The possibility of their application to NPPs was evaluated using data for each algorithm from two-dosimeter results for an inhomogeneous high radiation field during maintenance periods at Korean NPPs. (author)

  16. A passive environmental 222Rn monitor based on the exoelectron dosimeter

    International Nuclear Information System (INIS)

    Gammage, R.B.; Cheka, J.S.; Gesell, T.F.

    1978-01-01

    A high efficiency for BeO ceramic exoelectron dosimeters is demonstrated in the integrated monitoring of Mylar radon at concentrations close to natural background levels. Electrostatic collection of radon daughters onto aluminized mylar foil covering a BeO disk is achieved inside a porous, hemispherical chamber of the type developed by Costa-Ribeiro et al. This application of the exoelectron dosimeter for radon monitoring inside dwellings is a particularly favorable one; the lack of excessively high humidities and the clean conditions inside the hemisphere favor the reliable performance of the exoelectron dosimeter. Radon concentration - exposure times of 3 pCi h/l, or more, can be measured with an accuracy of about +-25% when the temperature and relative humidity are fluctuating. This means that radon concentrations of a few tenths of a pCi/l can be measured using exposure times of only a day or two. (Auth.)

  17. X-ray computer tomography, ultrasound and vibrational spectroscopic evaluation techniques of polymer gel dosimeters

    International Nuclear Information System (INIS)

    Baldock, Clive

    2004-01-01

    Since Gore et al published their paper on Fricke gel dosimetry, the predominant method of evaluation of both Fricke and polymer gel dosimeters has been magnetic resonance imaging (MRI). More recently optical computer tomography (CT) has also been a favourable evaluation method. Other techniques have been explored and developed as potential evaluation techniques in gel dosimetry. This paper reviews these other developments

  18. Isotopic exchange in a neutron-irradiated mixed-valence compound: Tl3(I) Tl(III)Cl6

    International Nuclear Information System (INIS)

    Fernandez Valverde, S.; Duplatre, G.

    1977-01-01

    The initial distribution of Tl(I) and Tl(III) species, and its change on heating, have been investigated in solid thermal neutron-irradiated Th 4 Cl 6 . An initial ratio of 5/1 for 204 Tl(I)/ 204 Tl(III) is found and this remains constant for integral gamma-doses of 3 to 12 MRad. The variation of the 204 Tl(III) fraction with temperature is found identical to that observed in labelled Tl 4 Cl 6 for which a genuine isotopic exchange has previously been described. It is concluded that the recoil species are rapidly converted, after the recoil processes, into stable ions

  19. Dose measurements using thermoluminescent dosimeters and DoseCal software at two paediatric hospitals in Rio de Janeiro

    International Nuclear Information System (INIS)

    Mohamadain, K.E.M.; Azevedo, A.C.P.; Rosa, L.A.R. da; Guebel, M.R.N.; Boechat, M.C.B.

    2003-01-01

    A dosimetric survey in paediatric radiology is currently being carried out at the paediatric units of two large hospitals in Rio de Janeiro city: IPPMG (Instituto de Pediatria e Puericultura Martagao Gesteira, University Hospital of Federal University of Rio de Janeiro) and IFF (Instituto Fernandes Figueira, FIOCRUZ). Chest X-ray examination doses for AP, PA and LAT projections of paediatric patients have been obtained with thermoluminescent dosimeters (TLDs) and with use of a software package DoseCal. In IPPMG and IFF 100 patients have been evaluated with the use of the TLDs and another group of 100 patients with the DoseCal software. The aim of this work was to estimate the entrance skin dose (ESD) for frontal, back and lateral chest X-rays exposure of paediatric patients. For ESD evaluation, three different TL dosimeters have been used, namely LIF:Mg, Ti (TLD100), CaSO 4 :Dy and LiF:Mg, Cu, P (TLD100H). The age intervals considered were 0-1, 1-5, 5-10 and 10-15 years. The results obtained with all dosimeters are similar, and it is in good agreement with the DoseCal software, especially for AP and PA projections. However, some larger discrepancies are presented for the LAT projection

  20. A new electret dosimeter for fast neutrons

    International Nuclear Information System (INIS)

    Campos, L.L.; Suarez, A.A.; Mascarenhas, S.

    1982-01-01

    A new electret for fast-neutron personnel dosimetry is described and calibration curves obtained. Its performance may be improved by changes in the wall composition and geometric parameters. The advantages of electrets over TL and film are the non-erasure of information, low cost, fast reading and portability. (U.K.)

  1. Dosimeter incorporating radiophotoluminescent detectors for thermal neutrons and γ-rays in n-γ fields

    Energy Technology Data Exchange (ETDEWEB)

    Salem, Y.O. [Groupe RaMsEs, Institut Pluridisciplinaire Hubert Curien (IPHC), UMR 7178 CNRS/IN2P3, 23 rue du Loess, BP 28, F-67037 Strasbourg Cedex 2 (France); Nachab, A., E-mail: a.nachab@uca.ma [Département de physique, Faculté Poly-disciplinaire, Université Cadi Ayyad, Route Sidi Bouzid BP 4162, 46000 Safi (Morocco); Roy, C.; Nourreddine, A. [Groupe RaMsEs, Institut Pluridisciplinaire Hubert Curien (IPHC), UMR 7178 CNRS/IN2P3, 23 rue du Loess, BP 28, F-67037 Strasbourg Cedex 2 (France)

    2016-10-15

    We have developed a dosimeter associating different neutron converters with two radiophotoluminescent detectors to measure thermal neutrons and γ-rays in a mixed n-γ field. Tests show that the H{sup ∗}(10) and H{sub p}(10) responses to thermal neutrons and γ-rays are linear with detection limits lower than 0.4 mSv. The angular dependence of the dosimeter response is satisfactory and the influence of a phantom on the results is examined.

  2. A CaS : Ce, Sm-based dosimeter for online dosimetry measurement

    International Nuclear Information System (INIS)

    Sun Yurun; Chen Zhaoyang; Fan Yanwei; Yan Shiyou; He Chengfa

    2011-01-01

    A film dosimeter based on optically stimulated luminescence (OSL) material of CaS : Ce, Sm was developed for online irradiation dosimetry measurement. The stimulation is provided by a laser with a wavelength of 980 nm, and the OSL luminescence is collected by a photodiode. Using 60 Co γ-rays, we investigated the dosimetry characteristic of the dosimeter at different dose rates and total doses. The real-time detection results showed that the OSL signals versus total ionizing dose exhibited a good linearity in a dose range of 0.1-185 Gy. (authors)

  3. Automation of dosimeters calibration for radiotherapy in secondary dosimetric calibration laboratory of the CPHR

    International Nuclear Information System (INIS)

    Acosta, Andy L. Romero; Lores, Stefan Gutierrez

    2013-01-01

    This paper presents the design and implementation of an automated system for measurements in the calibration of reference radiation dosimeters. It was made a software application that performs the acquisition of the measured values of electric charge, calculated calibration coefficient and automates the calibration certificate issuance. These values are stored in a log file on a PC. The use of the application improves control over the calibration process, helps to humanize the work and reduces personnel exposure. The tool developed has been applied to the calibration of dosimeters radiation patterns in the LSCD of the Centro de Proteccion e Higiene de las Radiaciones, Cuba

  4. The status of ANSI N13.11 - The dosimeter performance test standard

    International Nuclear Information System (INIS)

    Sims, C.S.

    1991-01-01

    The standard designated ANSI N13.11 was issued in 1983 and is the basis for the dosimeter performance test associated with the National Voluntary Laboratory Accreditation Program (NVLAP). The standard is important because the Nuclear Regulatory Commission requires that all licensees use personnel dosimeters processed by NVLAP-accredited processors. The standard has undergone review and modifications have been recommended. Historical information concerning the development and utilization of the present standard, ANSI N13.11-1983, is presented. Details associated with the review of the standard (e.g., policy, group selection) are then given. Finally, the modifications recommended by the review group are discussed

  5. Review of doped silica glass optical fibre: Their TL properties and potential applications in radiation therapy dosimetry

    International Nuclear Information System (INIS)

    Bradley, D.A.; Hugtenburg, R.P.; Nisbet, A.; Abdul Rahman, Ahmad Taufek; Issa, Fatma; Mohd Noor, Noramaliza; Alalawi, Amani

    2012-01-01

    Review is made of dosimetric studies of Ge-doped SiO 2 telecommunication fibre as a 1-D thermoluminescence (TL) system for therapeutic applications. To-date, the response of these fibres has been investigated for UV sources, superficial X-ray beam therapy facilities, a synchrotron microbeam facility, electron linear accelerators, protons, neutrons and alpha particles, covering the energy range from a few eV to several MeV. Dosimetric characteristics include, reproducibility, fading, dose response, reciprocity between TL yield and dose-rate and energy dependence. The fibres produce a flat response to fixed photon and electron doses to within better than 3% of the mean TL distribution. Irradiated Ge-doped SiO 2 optical fibres show limited signal fading, with an average loss of TL signal of ∼0.4% per day. In terms of dose response, Ge-doped SiO 2 optical fibres have been shown to provide linearity to x and electron doses, from a fraction of 1 Gy up to 2 kGy. The dosimeters have also been used in measuring photoelectron generation from iodinated contrast media; TL yields being some 60% greater in the presence of iodine than in its absence. The review is accompanied by previously unpublished data. - Highlights: ► We review our TLD studies of Ge-doped SiO 2 fibres for therapeutic applications. ► Sources include UV, X-rays, protons, neutrons and alpha particles. ► These TLDs have also been used to measure photoelectrons from I 2 contrast media. ► The review is accompanied by previously unpublished data.

  6. Preliminary study of diffusion effects in Fricke gel dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Quiroga, A. [Centro de Investigacion y Estudios de Matematica de Cordoba, Oficina 318 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina); Vedelago, J. [Laboratorio de Investigaciones e Instrumentacion en Fisica Aplicada a la Medicina e Imagenes por Rayos X, Laboratorio 448 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina); Valente, M., E-mail: aiquiroga@famaf.unc.edu [Instituto de Fisica Enrique Gaviola, Oficina 102 FaMAF - UNC, Av. Luis Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2014-08-15

    in standard dependence of optical density differences and actual, non-diffused, absorbed dose distributions. The obtained values for ferric ion diffusion coefficient, in mm{sup 2} h{sup -1} were (1.24 ± 0.07) and (1.15 ± 0.05) for the 1D and 2D method, respectively, in the first approach method and (0.65 ± 0.01), (0.68 ± 0.02) and (0.65 ± 0.02) in the second approach method. The results show good agreement with previous works corresponding to similar Fricke gel dosimeter compositions. Thus, more accurate 2D and 3D dose mapping might be attained that constitutes valuable improvements in Fricke gel dosimetry, and parallel a high precision methods of diffusion model and calculation have been developed. (Author)

  7. Preliminary study of diffusion effects in Fricke gel dosimeters

    International Nuclear Information System (INIS)

    Quiroga, A.; Vedelago, J.; Valente, M.

    2014-08-01

    in standard dependence of optical density differences and actual, non-diffused, absorbed dose distributions. The obtained values for ferric ion diffusion coefficient, in mm 2 h -1 were (1.24 ± 0.07) and (1.15 ± 0.05) for the 1D and 2D method, respectively, in the first approach method and (0.65 ± 0.01), (0.68 ± 0.02) and (0.65 ± 0.02) in the second approach method. The results show good agreement with previous works corresponding to similar Fricke gel dosimeter compositions. Thus, more accurate 2D and 3D dose mapping might be attained that constitutes valuable improvements in Fricke gel dosimetry, and parallel a high precision methods of diffusion model and calculation have been developed. (Author)

  8. Radiation Dose Measurement Using Chemical Dosimeters

    International Nuclear Information System (INIS)

    Lee, Min Sun; Kim, Eun Hee; Kim, Yu Ri; Han, Bum Soo

    2010-01-01

    The radiation dose can be estimated in various ways. Dose estimates can be obtained by either experiment or theoretical analysis. In experiments, radiation impact is assessed by measuring any change caused by energy deposition to the exposed matter, in terms of energy state (physical change), chemical production (chemical change) or biological abnormality (biological change). The chemical dosimetry is based on the implication that the energy deposited to the matter can be inferred from the consequential change in chemical production. The chemical dosimetry usually works on the sample that is an aqueous solution, a biological matter, or an organic substance. In this study, we estimated absorbed doses by quantitating chemical changes in matter caused by radiation exposure. Two different chemical dosimeters, Fricke and ECB (Ethanol-Chlorobenzene) dosimeter, were compared in several features including efficacy as dose indicator and effective dose range

  9. Sensitive color dosimeters using photochromic diarylethenes

    International Nuclear Information System (INIS)

    Irie, Setsuko; Irie, Masahiro

    2008-01-01

    Various types of color dosimeters are conveniently used for estimating absorbed dose in the radiation sterilization of biomedical materials. Diarylethenes with heterocyclic aryl groups are extensively studied for the applications to the optoelectronic devices, such as optical memory media and photowitching devices because of their thermally irreversible and fatigue-resistant properties. The colors of diarylethenes never fade in the dark conditions. The thermally stable dithienylethene derivatives are applied to sensitive color dosimeters. Upon γ-irradiation, polystyrene films containing diarylethene derivatives, such as 1,2-bis(2-methyl-5-phenyl-3-thienyl) perfluorocyclopentene 1 or 1,2-bis(2,5-dimethyl-3-thienyl) perfluorocyclopentene 2, and fluorescent metal complexes turned blue or red. Even if the absorbed dose was as small as 10 Gy, a clear color change was observed. (author)

  10. Individual dosimeter for radon and thoron daughters

    International Nuclear Information System (INIS)

    Chapuis, A.M.; Duport, P.; Zettwoog, P.

    1979-01-01

    The dosimeter is designed for the continuous measurement of the concentration of α emitters from the uranium 238 and thorium 232 series. It enables the measurement of, firstly the aerosol concentration of 218 Po (Radium A), 214 Po (Radium C') and 212 Po (Thorium C') and secondly the activity of long-lived α emitters in aerosols coming from ore dusts. One light weight version of this dosimeter is autonomous for 18 hours and is designed to measure individual doses, due to inhalation, for workers employed in uranium mines and ore processing plants. An other version using the same sampling head allows the monitoring of air concentrations in working environments. Living quarters, or free air

  11. Human hair as a pollutant dosimeter

    International Nuclear Information System (INIS)

    Al-Hashimi, A.

    1991-01-01

    Human hair has been proved to be a better dosimeter than even blood for tracing most of the heavy metal toxins when they penetrate the biosphere. The high precision of the neutron activation analysis (NAA) enabled researchers to elegantly differentiate between endogenous and exogenous contamination and thoroughly study poisonings caused by these physiologically-unimportant elements. Extensive volume of bench-scale work has been accomplished in these laboratories to show the capacity of INAA to detect the presence of 10 nuclides (or more) with a precision of about 5%. The principal objective of the present study is to employ this assaying power and the tendency of scalp hair to uptake heavy metals from aqueous solutions, to design a dosimeter which can easily be used by the environmentalists. The findings should also be of interest to the waste-management people who are searching for a cost-effective technique to remove these pollutants from relatively large volumes of industrial effluents

  12. High dose potassium-nitrate chemical dosimeter

    International Nuclear Information System (INIS)

    Dorda de Cancio, E.M.; Munoz, S.S.

    1982-01-01

    This dosimeter is used to control 10 kGY-order doses (1 Mrad). Nitrate suffers a radiolitic reduction phenomena, which is related to the given dose. The method to use potassium nitrate as dosimeter is described, as well as effects of the temperature of irradiation, pH, nitrate concentration and post-irradiation stability. Nitrate powder was irradiated at a Semi-Industrial Plant, at Centro Atomico Ezeiza, and also in a Gammacell-220 irradiator. The dose rates used were 2,60 and 1,80 KGY/hour, and the given doses varied between 1,0 and 150 KGY. The uncertainty was +-3% in all the range. (author) [es

  13. A pocket type thermoluminescent personnel dosimeter

    International Nuclear Information System (INIS)

    Vora, K.G.; Nagpal, J.S.; Pendurkar, H.K.; Gangadharan, P.

    1979-01-01

    A pocket type thermoluminescent personnel dosemeter using CaSO 4 : Dy phosphor is described. Two glass capillaries containing the phosphor are fitted into a plastic tube and covered by a cylindrical filter. The combination is fitted into an ink barrel of a fountain pen. The response of this Dy glass dosimeter was studied for various incident photon energies. A uniform response over the energy range from 33 keV to 1250 keV is achieved. (A.K.)

  14. Phosphor for thermoluminescent type radiation dosimeter

    International Nuclear Information System (INIS)

    Nada, N.; Yamashita, T.

    1975-01-01

    This has the accumulation effect of radiation energy and is mainly used as the element for thermoluminescent type radiation dosimeters. It has as the principal constituent a phosphor consisting of calcium sulfate as the principal constituent and other impurity elements such as dysprosium, thulium and the like. It is more sensitive by the order of 1 to 2 or more figures than the conventional ones and is excellent in the retention of absorbed radiation energy. (U.S.)

  15. Dosimeter characteristics and service performance requirements

    International Nuclear Information System (INIS)

    Ambrosi, P.; Bartlett, D.T.

    1999-01-01

    The requirements for personal dosimeters and dosimetry services given by ICRP 26, ICRP 35, ICRP 60 and ICRP 75 are summarised and compared with the requirements given in relevant international standards. Most standards could be made more relevant to actual workplace conditions. In some standards, the required tests of energy and angular dependence of the response are not sufficient, or requirements on overall uncertainty are lacking. (author)

  16. Color-indicator dosimeter for ionizing radiation

    International Nuclear Information System (INIS)

    Panchenkov, G.M.; Kozlov, L.L.; Molin, A.A.; Ershova, Z.F.; Mikhailov, L.M.; Juzvyak, A.G.; Valitov, R.B.; Churov, V.P.; Grinev, M.P.

    1980-01-01

    Colorimetric dosimeter of ionizing radiation, containing 70-100 w % of a thermoplastic polymer, 10-40 w. % of a softener, 0.5-3.0 w. % of stabilizer and two dyes compatible with the polymer is designed. The first dye is chosen among zanthene- polymethine- or pyrazolon dyes, while the other is a triarylmethane- indigo- thiazine- indophenol- indiamine- or indaniline dye. (E.G.)

  17. (Tl, Sb) and (Tl, Bi) binary surface reconstructions on Ge(111) substrate

    Science.gov (United States)

    Gruznev, D. V.; Bondarenko, L. V.; Tupchaya, A. Y.; Yakovlev, A. A.; Mihalyuk, A. N.; Zotov, A. V.; Saranin, A. A.

    2018-03-01

    2D compounds made of Group-III and Group-V elements on the surface of silicon and germanium attract considerable attention due to prospects of creating III-V binary monolayers, which are predicted to hold advanced physical properties. In the present work, we have investigated two such systems, (Tl, Sb)/Ge(111) and (Tl, Bi)/Ge(111) using scanning tunneling microscopy, low energy electron diffraction observations and density-functional-theory calculations. In addition to the previously reported surface structures of 2D (Tl, Sb) and (Tl, Bi) compounds on Si(111), we found new ones, namely, √{ 7} × √{ 7} and 3 × 3. Formation processes and plausible models of their atomic arrangements are discussed.

  18. A modified Fricke gel dosimeter for fast electron blood dosimetry

    International Nuclear Information System (INIS)

    Del Lama, L.S.; Góes, E.G. de; Sampaio, F.G.A.; Petchevist, P.C.D.; Almeida, A. de

    2014-01-01

    It has been suggested for more than forty years that blood and blood components be irradiated before allogeneic transfusions for immunosuppressed patients in order to avoid the Transfusion-Associated Graft-versus-Host Disease (TA-GVHD). Whole blood, red blood cells, platelets and granulocytes may have viable T cells and should be irradiated before transfusion for different patient clinical conditions. According to international guides, absorbed doses from 25 up to 50 Gy should be delivered to the central middle plane of each blood bag. Although gamma and X-rays from radiotherapy equipments and dedicated cell irradiators are commonly used for this purpose, electron beams from Linear Accelerators (LINACs) could be used as well. In this work, we developed a methodology able to acquire dosimetric data from blood irradiations, especially after fast electrons exposures. This was achieved using a proposed Fricke Xylenol Gel (FXG p ) dosimeter, which presents closer radiological characteristics (attenuation coefficients and stopping-powers) to the whole blood, as well as complete absorbed dose range linearity. The developed methodology and the FXG p dosimeter were also able to provide isodose curves and field profiles for the irradiated samples

  19. A modified Fricke gel dosimeter for fast electron blood dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Del Lama, L.S., E-mail: lucasdellama@gmail.com [Departamento de Fsica, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo (FFCLRP/USP), Av. Bandeirantes, 3900, CEP 14040-901, Bairro Monte Alegre, Ribeirão Preto, São Paulo (Brazil); Góes, E.G. de [Instituto de Matemática, Estatística e Física, Universidade Federal de Rio Grande (IMEF/FURG), Av. Itália, km 8, CEP 96201-900, Bairro Carreiros, Rio Grande, Rio Grande do Sul (Brazil); Sampaio, F.G.A.; Petchevist, P.C.D.; Almeida, A. de [Departamento de Fsica, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo (FFCLRP/USP), Av. Bandeirantes, 3900, CEP 14040-901, Bairro Monte Alegre, Ribeirão Preto, São Paulo (Brazil)

    2014-12-15

    It has been suggested for more than forty years that blood and blood components be irradiated before allogeneic transfusions for immunosuppressed patients in order to avoid the Transfusion-Associated Graft-versus-Host Disease (TA-GVHD). Whole blood, red blood cells, platelets and granulocytes may have viable T cells and should be irradiated before transfusion for different patient clinical conditions. According to international guides, absorbed doses from 25 up to 50 Gy should be delivered to the central middle plane of each blood bag. Although gamma and X-rays from radiotherapy equipments and dedicated cell irradiators are commonly used for this purpose, electron beams from Linear Accelerators (LINACs) could be used as well. In this work, we developed a methodology able to acquire dosimetric data from blood irradiations, especially after fast electrons exposures. This was achieved using a proposed Fricke Xylenol Gel (FXG{sub p}) dosimeter, which presents closer radiological characteristics (attenuation coefficients and stopping-powers) to the whole blood, as well as complete absorbed dose range linearity. The developed methodology and the FXG{sub p} dosimeter were also able to provide isodose curves and field profiles for the irradiated samples.

  20. Thin layer alanine dosimeter with optical spectrophotometric evaluation

    International Nuclear Information System (INIS)

    Zagorski, Z.P.

    2000-01-01

    Experience in the high dose dosimetry of gamma radiation, gathered in our group from the sixties till now, allows to express the opinion, that techniques applied are adequate to solve problems. It can be confirmed by the fact that 60% of laboratories participating in the international comparison during the duration of the contract obtained satisfactory results. Adaptation of these methods, in particular of the alanine-ESR dosimetry to highly inhomogeneous fields of EB gives poor results, as it has been shown on thin films of the alanine/polymer composite. However, the applications of these films give excellent results if the concentration of the radical CH 3 C·H CO 2 - is measured by diffuse reflection spectrophotometry, which tolerates poor transparency of the composite and is insensitive to the orientation of crystals of alanine in thin films, what is disqualifying the ESR measurements. The development of thin-film dosimeters for EB processing was possible due to new developments in solid state radiation chemistry. The research has revealed some unsolved questions, e.g. of the high temperature coefficient of alanine based dosimeters, of the role of the size of spurs and the necessity to adapt dosimetry to the energy spectrum of electrons, because every type of accelerators differs in that respect. (author)

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

    International Nuclear Information System (INIS)

    Chen, Felipe; Graeff, Carlos F.O.; Baffa, Oswaldo

    2005-01-01

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

  2. Operational aspects of the direct ion storage dosimeter system: 18 months of experience at CERN

    International Nuclear Information System (INIS)

    Carbonez, P.; Kotamaki, E.; Otto, Th.

    2006-01-01

    CERN, the European Organization for Nuclear Research, operates a dosimetry service for external exposure. The service monitors approximately 5000 Staff, scientific visitors and contractors personnel working on the organizations sites with personal dosimeters for personal dose equivalent (Hp(10), Hp(0.07)) from gamma, beta and neutron radiation. The dosimetry service is approved by the Swiss Federal Health Office, the competent authority for radiation protection. In 2004, the R.A.D.O.S. D.I.S. -1 dosemeter has been introduced to CERN as a gamma-beta dosemeter. Technical characteristics of this dosimeter, based on the direct ion storage technology, are high sensitivity, excellent linearity of the personal dose response with respect to radiation energy or dose, and long-term physical storage of personal dose-related information without the risk of fading. One important technical feature of the dosemeter is its 'instant reading' capability: the user himself can evaluate the received personal dose nondestructively on specific reader stations. This information is digitized, centralized by the CERN-wide network and stored in a database. The consequence of the 'instant reading' capability is a break with in the traditional organisation of a dosimetry service. The personal dosimeters are no longer exchanged periodically for evaluation, but a monthly value of personal dose is calculated from the readings initiated by the user. After a wearing period of one year, users are invited to exchange the dosimeter against a new, recently calibrated unit. The introduction of the D.I.S.-1 dosimeter has profoundly changed the type of work in CERN dosimetry service. Technical and laboratory work (development of film dosimeters, densitometric evaluation) have made place for computer-based procedures and database management. (authors)

  3. Principles of Good Practice in SoTL

    Science.gov (United States)

    Felten, Peter

    2013-01-01

    For the Scholarship of Teaching and Learning (SoTL) to be understood as significant intellectual work in the academy, SoTL practitioners need to identify shared principles of good practice. While honoring the diversity of SoTL in its many forms across the globe, such principles can serve as a heuristic for assessing work in our field. These…

  4. Anthracene dosimeter characterization under radiotherapy photons

    International Nuclear Information System (INIS)

    Czelusniak, Caroline

    2011-01-01

    New radiotherapy techniques such as intensity-modulated radiation therapy and stereotactic radiosurgery have increased the need for dosimeters that can provide measurements in real time with high spatial resolution. Organic scintillation dosimeters are able to measure with accuracy small radiation fields and fields with high gradients, besides having advantages such as water and soft tissue equivalence and the possibility to be used in vivo. Anthracene is an organic scintillator crystal with the highest known scintillation efficiency among organic scintillation materials. The objective of this work is to characterize the anthracene as a dosimeter under radiotherapy photons energies, analysing its signal against average granulosity, intern capsule diameter, absorbed dose, absorbed dose rate, photon energy and its spatial resolution; with the last one analysed under three methods (edge spread function, line spread function and modulation transfer function). The photons energies used were 1.25 MeV ( 60 Co), 0.661 MeV ( 137 Cs) and X-rays (effective energies of 28.4; 46.5; 48.5; 94.0 e 106.0 keV). The scintillation detection system consisted of an optical fiber with one end attached to the anthracene capsule and the other to a photomultiplier tube maintained by power supply followed by an electrometer. Once Cerenkov radiation occurs in the optical fiber, it was removed from the total scintillation signal trough the subtraction of the signal, taken irradiating the optical fiber without the anthracene attached to one of its extremity. From results obtained, one can infer that the dosimeter signal increases proportionally with average granulosity and intern capsule diameter. The signal is linearly dependent of absorbed dose, linearly dependent of low photons energies and independent for high photons energies, as well as independent of the absorbed dose rate. From the spatial resolution values obtained it was possible to infer that the one obtained through modulation

  5. Comparison of electronic digital alarm dosimeter with TLD

    International Nuclear Information System (INIS)

    Kumar, Pankaj; Pandey, J.P.N.; Shinde, A M.; Purohit, R.G.; Sarkar, P.K.

    2012-01-01

    Control of exposure of radiation workers on day to day basis has been made easy by use of semiconductor based electronic digital dosimeter. Additional dose constraints of 10 mSv for occupational radiation workers have made it essential to use such type of digital personal monitoring devices. In addition to conventional ionisation chamber based direct reading dosimeters, additional 35 semiconductor based digital dosimeters model MGP DMC 2000 S were used for the monitoring of personal exposure of radiation workers in a spent fuel reprocessing plant. Though better least count and good performance over a wide range of dose rate are claimed by the manufacture, before making use of such dosimeter on large scale, validation of its performance is required to be checked. In this paper, an effort is made to determine the performance of digital dosimeters, by exposing these digital dosimeters in combination with TLDs at different radiation levels and obtained results were compared and analysed

  6. Dose measurement during defectoscopic work using electronic personal dosimeters

    International Nuclear Information System (INIS)

    Smoldasova, J.

    2008-01-01

    Personal monitoring of the external radiation of radiation, personnel exposed to sources of ionizing radiation at a workplace is an important task of the radiological protection. Information based on the measured quantities characterizing the level of the exposure of radiation personnel enable to assess the optimum radiological protection at the relevant workplace and ascertain any deviation from the normal operation in time. Different types of personal dosimeters are used to monitor the external radiation of radiation personnel. Basically, there are two types of dosimeters, passive and active (electronic). Passive dosimeters provide information on the dose of exposure after its evaluation, while electronic dosimeters provide this information instantly. The goal of the work is to compare data acquired during different working activities using the DMC 2000 XB electronic dosimeters and the passive film dosimeters currently used at the defectoscopic workplace. (authors)

  7. TL and OSL studies of carbon doped magnesium aluminate (MgAl2O4:C)

    Science.gov (United States)

    Raj, Sanu S.; Mishra, D. R.; Soni, Anuj; Grover, V.; Polymeris, G. S.; Muthe, K. P.; Jha, S. K.; Tyagi, A. K.

    2016-10-01

    The MgAl2O4:C has been synthesized by using two different methods by electron gun and vacuum assisted melting of MgAl2O4 in presence of graphite. The MgAl2O4:C phosphor thus developed by these two different methods have similar types of the TL/OSL defects with multiple overlapping TL glow peaks from 100 °C to 400 °C. The Computerized Curve De-convolution Analysis (CCDA) has been used to measure TL parameters such as thermal trap depth, frequency factor and order of kinetic associated with charge transfer process in TL phenomenon. The investigated TL/OSL results show that these two methods of incorporating carbon in MgAl2O4 have generated closely resemble the defects of similar types in MgAl2O4:C lattice. However, the MgAl2O4:C synthesized by electron gun shows relatively larger concentration of the TL/OSL defects as compared to MgAl2O4:C synthesized using vacuum assisted melting method. The photo-ionization cross-section (PIC) associated with fastest OSL component of MgAl2O4: C is found to be ∼ 0.5 times than that of fastest OSL component of commercially available dosimetric grade α-Al2O3:C. The MgAl2O4:C thus developed shows good dynamic OSL dose linearity from few mGy to 1 Gy. This work reveals that MgAl2O4:C could be developed as potential tissue equivalent OSL / TL material.

  8. Improvement of routes and production of CaSO{sub 4}-based dosimeters with unusual doping; Aprimoramento de rotas e producao de dosimetros a base de CaSO{sub 4} com dopagens nao usuais

    Energy Technology Data Exchange (ETDEWEB)

    Junot, Danilo Oliveira

    2017-07-01

    The widespread use of ionizing radiation in medicine and industry, associated with the known risks that this type of radiation can cause, has motivated the search for new radiation detectors, seeking improvements in the dosimetric characteristics and in the cost of production in comparison with commercial dosimeters disseminated. The motivation of this work is, therefore, to produce new thermoluminescent detectors through improved routes. Unusual elements in CaSO{sub 4} matrix doping, such as terbium (Tb) and ytterbium (Yb), were used as dopants in this matrix, as well as the europium (Eu), the thulium (Tm) and the silver (Ag), resulting in samples of CaSO{sub 4}:Eu,Tb, CaSO{sub 4}:Tb,Yb, CaSO{sub 4}:Tm,Ag and CaSO{sub 4}:Eu,Ag that were prepared by means of an adaptation of the method developed by Yamashita (1971). The route of synthesis is based on the mixture of calcium carbonate (CaCO{sub 3}) and dopant oxide (except for silver, incorporated in the form of metallic nanoparticles) in a solution of sulfuric acid. The mixture is heated until all the acid evaporates and only the powder of the material remains. In this route, the sulfuric acid is collected and can be reused. The phosphors produced were characterized by X-ray diffraction and radioluminescence techniques. The silver particles, produced by the polyol method, were characterized by scanning electron microscopy. Composites were obtained from the addition of Teflon to the phosphors. The thermoluminescence (TL) and the optically stimulated luminescence (OSL) of the new materials produced were investigated. Thermoluminescent characteristics such as sensitivity, linearity, reproducibility, minimum detectable dose, kinetic order and fading were evaluated and discussed. The CaSO{sub 4}:Tb,Eu composites showed TL glow curves with peaks at temperatures of 170 °C, 270 °C and 340 °C. The CaSO{sub 4}:Tb,Yb composites presented TL glow curves with peaks at temperatures of 90 °C, 160 °C, 240 °C and 340 °C. Ca

  9. A new method for crosstalk correction in simultaneous dual-isotope myocardial imaging with Tl-201 and I-123

    International Nuclear Information System (INIS)

    Tsuji, Akinori; Kojima, Akihiro; Oyama, Yoichi; Tomiguchi, Seiji; Kira, Tomohiro; Takagi, Yoshikazu; Shimomura, Osamu; Takahashi, Mutsumasa; Matsumoto, Masanori

    1999-01-01

    We have developed a new method of crosstalk correction in simultaneous dual-isotope imaging with Tl-201 and I-123 by using crosstalk ratios and a blurring filter. Single isotope myocardial studies (10 for Tl-201 and 7 for I-123) were performed with a dual energy window acquisition mode and two low energy general-purpose collimators. Then two planar images acquired with dual energy windows for a Tl-201 line source and an I-123 line source were obtained to measure line spread functions (LSFs) and crosstalk ratios for each image. The line source experiments showed that the LSFs for the Tl-201 imaging window from the single Tl-201 source were very similar to those for the I-123 imaging window from the single Tl-201 source, but the LSFs for the Tl-201 imaging window from the single I-123 source had broad shapes which differed from those for the I-123 imaging window from the single I-123. To obtain accurate I-123 crosstalk images in the Tl-201 imaging window from the I-123 images in the I-123 imaging window, we designed a low-pass blurring filter. In 7 clinical I-123 MIBG studies, I-123 window images processed with this filter became very similar to the Tl-201 window image from the single I-123 source. The method proposed in this study can accurately correct the crosstalk in dual isotope studies with Tl-201 and I-123 and is easily applicable to conventional gamma camera systems with any dual energy window acquisition mode. (author)

  10. Automation of the Calibration of Reference Dosimeters Used in Radiotherapy

    International Nuclear Information System (INIS)

    Romero Acosta, A.; Gutierrez Lores, S.

    2013-01-01

    Traceability, accuracy and consistency of radiation measurements are essential in radiation dosimetry, particularly in radiotherapy, where the outcome of treatments is highly dependent on the radiation dose delivered to patients. The role of Secondary Standard Dosimetry Laboratories (SSDLs) is crucial in providing traceable calibrations to hospitals, since these laboratories disseminate calibrations at specific radiation qualities appropriate to the use of radiation measuring instruments. These laboratories follow IAEA/WHO guidelines for calibration procedures, often being current and charge measurements described in these guidelines a tedious task. However, these measurements are usually done using modern electrometers which are equipped with a RS-232 interface that allows instrument control from a PC. This paper presents the design and employment of an automated system aimed to the measurements of the radiotherapy dosimeters calibration process for Cobalt-60 gamma rays. A software was developed using Lab View, in order to achieve the acquisition of the charge values measured, calculation of the calibration coefficient and issue of a calibration certificate. A primary data report file is filled and stored in the PC's hard disk. By using this software tool, a better control over the calibration process is achieved, it reduces the need for human intervention and it also reduces the exposure of the laboratory staff. The automated system has been used for the calibration of reference dosimeters used in radiotherapy at the Cuban Secondary Standard Dosimetry Laboratory of the Center for Radiation Protection and Hygiene (Author)

  11. Work place monitoring in accelerator facilities using thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    Ribeiro, M.S.; Sanches, M.P.; Osima, A.M.; Rodriguez, D.L.; Carvalho, R.N.; Somessari, R.N.

    1998-01-01

    The increase in the use of large amounts of energy and large particles accelerators in development or in industrial processes for the reticulation, polymerization and sterilization of cables and wires allowed to discover and monitor work places in facilities having particle accelerators at the Institute of Energy and Nuclear Inquiries Comissao National de Energy Nuclear. Measures previously taken by technicians in routine monitoring, show that radiation doses found in the beams tube and at the door of the accelerator area is high enough to require routine programs to monitor work places at the installation. That is why, fifteen thermoluminescent dosimeters (TLD) where placed in different points of the facility where doses must be measured along a three month period and at the same time readings must be taken from control dosimeters kept within a shielded container. The monitor had a small double layer with three pellets of TLD CaSO4 Dy inside of a route carrier adopted in routine workers dosimetry usually. Outcomes show that the radiological protection program must be implemented to ameliorate and guarantee safety procedures

  12. Dehydrochlorinated poly vinyl alcohol (PVA) films for food irradiation dosimeters

    International Nuclear Information System (INIS)

    Susilawati; Saion, E.B.; Doyan, A.; Lepit, A.; Wan Yusoff, W.M.D.

    2002-01-01

    Radiation sensitive dosimeters based on dyed poly vinyl alcohol (PVA) films containing chloral hydrate CCl 3 CH(OH) 2 and acid-sensitive cresol-red dye have been developed for use in food irradiation dosimetry. These polymer dosimeters undergo colour change from yellow (colour of basic form) to red (colour of acid form) upon exposure to gamma radiation. The radiation-induced change in colour was analysed using UV-Vis spectrometer. The absorption spectra produced two absorption modes, peaking at 438 nm for low doses and 529 nm for high doses. The dose-response was obtained by the changes in absorbance as a function of the absorbed dose. Results of the dose-response curves show the absorption decreases and increases experientially at modes 438 nm and 529 nm respectively with absorbed dose. The change in colour of the irradiated films was analysed using Raman spectrometer, which provides the spectra of molecular stretching modes of vibration of some chemical bonds in the films. The relative intensity at C-Cl stretching peaks of chloral hydrate decreases with absorbed dose and makes the films more acidic. Consequently the relative intensity at S-H and C=C stretching peaks of the dye increases with absorbed dose as the acid reacts with the dye and changes the structure and colour of the dye. (Author)

  13. Hanford beta-gamma personnel dosimeter prototypes and evaluation

    International Nuclear Information System (INIS)

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

    1983-04-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-15

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

  15. Model-based visual tracking the OpenTL framework

    CERN Document Server

    Panin, Giorgio

    2011-01-01

    This book has two main goals: to provide a unifed and structured overview of this growing field, as well as to propose a corresponding software framework, the OpenTL library, developed by the author and his working group at TUM-Informatik. The main objective of this work is to show, how most real-world application scenarios can be naturally cast into a common description vocabulary, and therefore implemented and tested in a fully modular and scalable way, through the defnition of a layered, object-oriented software architecture.The resulting architecture covers in a seamless way all processin

  16. Tl and OSL on diopside crystal

    International Nuclear Information System (INIS)

    Cano, N.F.; Watanabe, S.; Mittani, J.C.R.; Yukihara, E.G.

    2006-01-01

    The diopside with chemical composition CaMgSi 2 O 6 is part of an important solid solution series of the pyroxene group. The mineral is commonly found in meteorites and it is an important rock forming mineral of medium and high grade metamorphic rocks which are rich in calcium. In the bibliography it is possible to found several studies on electron spin resonance (ESR), reflectance, etc. but not on thermoluminescence (TL) or optically stimulated luminescence (OSL). In the present work we studied diopside TL and OSL behaviour on natural and natural irradiated samples. The sample used in our study is a white coloured diopside provided by Mineracao Sao Judas located in Sao Paulo, Brazil. The X-Ray Fluorescence technique has shown high concentrations of SiO 2 (55.81 % mol), CaO (23.47 % mol), MgO (18.03 % mol), Al 2 O 3 (1.56 % mol), Fe 2 O 3 (0.53 % mol), K 2 O (0.44 % mol), TiO 2 (0.065 % mol), P 2 O 5 (0.026 % mol), and MnO (0.013 % mol). TL measurements on natural samples show four TL peaks at 160, 260, 360, and 450 C. After beta-irradiation an increment mainly in the low temperature peaks is observed. As for OSL measurements, low OSL signal was observed on natural samples using blue light stimulation and UV detection. The intensity of the signal was observed to increase with the irradiation dose. (Author)

  17. Measurement of conversion coefficients in 208Tl

    International Nuclear Information System (INIS)

    Wendling, F.

    1976-06-01

    A electron spectrometer composed by a Li drifted Si detector and a uniform magnetic field was constructed. The magnetic field is used to focus the electrons on the detector and to filter the other radiations. After the construction the instrument was calibrated in absolute eficience and was used together with a Ge(Li) spectrometer also calibrated, in the measurement of internal conversion coeficients of the 433 and 453 keV transitions in 208 Tl [pt

  18. Evaluation of discrepancies between thermoluminescent dosimeter and direct-reading dosimeter results

    International Nuclear Information System (INIS)

    Shaw, K.R.

    1993-07-01

    Currently at Oak Ridge National Laboratory (ORNL), the responses of thermoluminescent dosimeters (TLDs) and direct-reading dosimeters (DRDs) are not officially compared or the discrepancies investigated. However, both may soon be required due to the new US Department of Energy (DOE) Radiological Control Manual. In the past, unofficial comparisons of the two dosimeters have led to discrepancies of up to 200%. This work was conducted to determine the reasons behind such discrepancies. For tests conducted with the TLDs, the reported dose was most often lower than the delivered dose, while DRDs most often responded higher than the delivered dose. Trends were identified in personnel DRD readings, and ft was concluded that more training and more control of the DRDs could improve their response. TLD responses have already begun to be improved; a new background subtraction method was implemented in April 1993, and a new dose algorithm is being considered. It was concluded that the DOE Radiological Control Manual requirements are reasonable for identifying discrepancies between dosimeter types, and more stringent administrative limits might even be considered

  19. IAEA reference dosimeter: Alanine-ESR

    International Nuclear Information System (INIS)

    Mehta, K.; Girzikowsky, R.

    1999-01-01

    Since 1985, the IAEA has been using alanine-ESR as a transfer dosimeter for its dose quality audit service, namely the International Dose Assurance Service. The alanine dosimeters are rod-type containing 70 wt% DL--α-alanine and 30 wt% polystyrene. We have two self-shielded gamma facilities for the calibration of the dosimetry system, where the temperature within the irradiation chamber can be controlled by a specially designed unit. A 4th order polynomial is fitted to the 16 data points in the dose range of 100 Gy to 50 kGy. The measured value of the irradiation temperature coefficient at two dose values (15 and 45 kGy) is 0.23 %/deg. C. Also, the ESR-response was followed for several dosimeters for about 8 months to study the post-irradiation effect. A value of 0.008 %/day was observed for the fading of the response for two dose values (15 and 45 kGy) and three irradiation temperatures (15, 27 and 40 deg. C). The effect of the analysis temperature on the ESR response was also studied. The combined relative uncertainty for the IAEA alanine-ESR dosimetry system is 1.5% (k=1). This includes that transferred from the primary laboratory for the dose rate measurements of the gamma facilities, dosimetry system calibration uncertainties, batch variability and uncertainty in the curve fitting procedure. This value however does not include the contribution due to the irradiation temperature correction which is applied when it differs from that during calibration; this component being specific for each dose measurement. (author)

  20. Thallium (Tl) sorption onto illite and smectite: Implications for Tl mobility in the environment

    Science.gov (United States)

    Martin, Loïc A.; Wissocq, Aubéry; Benedetti, M. F.; Latrille, Christelle

    2018-06-01

    Clay minerals play a relevant role in the transport and fate of trace elements in the environment. Though illite has been referred as an important Thallium (Tl) bearing phase in soils, mechanisms and affinity of thallium for clay minerals remain poorly known. This study investigated the sorption behavior of thallium as Tl(I) onto illite and smectite, two clay minerals occurring mainly in soils and sediments. Different sorption experiments were carried out under various pH conditions and Tl concentrations, in competition with sodium and calcium at a constant ionic strength of 0.01 mol L-1. Our results showed that illite displayed more affinity than smectite for thallium. With illite, the distribution coefficients (Kd in L kg-1) varied between 102.75 ± 0.17 and 104.0 ± 0.17 in Na solutions versus between 102.25 ± 0.17 and 103.0 ± 0.17 in Ca solutions, depending on pH. With smectite, Kd (in L kg-1) ranged between 102.50 ± 0.16 and 103.20 ± 0.16 and between 101.25 ± 0.16 and 101.95 ± 0.16 in Na and Ca solutions, respectively. Sorption behavior was described with the Multi-Site Ion Exchanger model and selectivity coefficients with respect to protons were calculated for the first time. In all cases, independently of clay mineral and background electrolyte, low capacity but highly reactive sites were dominant in thallium uptake, highlighting Tl affinity for those sites. Moreover, the exchangeable and reversible interactions between Tl+ and clays reactive sites suggested that in changing conditions, thallium could be released in solution. The role of clay minerals in thallium environmental cycle is evident and confirmed illite to be a dominant Tl bearing phase, in some environment competing with manganese oxides. Compared to others Tl bearing mineral phases, clays are ranked as follows: MnO2 > illite > smectite ∼ ferrihydrite ≥ Al2O3 ∼ goethite > SiO2. Finally, over the three monovalent cations (Tl, Rb, Cs) Tl is the one less sorbed on illite independently of

  1. Evaluation of fading factor and self-dose for glass dosimeter and thermoluminescence dosimeter

    International Nuclear Information System (INIS)

    Yamasaki, T.; Yamanishi, H.; Miyake, H.; Komura, K.

    2000-01-01

    The glass dosimeter (GD) and thermoluminescence dosimeter (TLD) are both passive radiation detectors. They are often used for measuring environmental radiation. In order to measure low dose rate preciously, it is important to evaluate decreased dose due to fading and self-dose during the exposure period. We evaluate the fading factor and self-dose of thee passive detectors, GD and TLD. We select Ogoya tunnel for the experiment. The tunnel is suitable field for measuring faded dose and self-dose because it is low cosmic radiation. At the center of the tunnel, the intensity of cosmic ray is reduced to about 1/177 than the outside of the funnel. We prepared two sets of dosimeters. One set consists of five GDs, five TLDs and some pre-irradiated GDs and TLDs that are exposed to standard radiation of 4 mGy by Cs-137. These dosimeters are put in the 10 cm thick lead box in order to shield the terrestrial gamma ray. One set is located at the center of the tunnel and the other is the outside of the funnel. The dosimeters were exposed for ten months, from May 1998 to March 1999. After the exposure, the readers of dosimeters are carried into the funnel to read out the signals promptly as soon as taking out the dosimeters. As a result of the measurement, four kinds of data are taken for GD and TLD respectively. Assumed that the self-dose and cosmic ray are constant during exposure, the four independent unknown quantities, a self-dose a dose due to cosmic ray and a fading coefficient at the center of the tunnel and at the outside, are considered. Therefore four simultaneous equations should be obtained. From these examinations, the faded dose of GD is less than 1%, but that of TLD is about 16% during ten months. The coefficient for compensation of fading of GD and TLD is given as the half of the each value. At the outside of the tunnel, the measured dose rate of cosmic ray that can pass through the 10 cm lead is evaluated to be about 16 nGy/h by both detectors. The self

  2. Importance of the effective atomic number (Zeff) of TL materials for radiation dosimetry in clinical applications

    International Nuclear Information System (INIS)

    Gonzalez M, P.R.

    2008-01-01

    The electric power generation, it has been one of the radiation applications of bigger weight, mainly in developed countries. Another sector of more impact is without a doubt that of the medicine. However, for a sure operation with radiations, those international organisms of radiological safety, exist every time more precise detection systems. The thermoluminescent dosimetry is one of the more reliable methods for this purpose, for that several groups of investigators from different parts of the world, they have guided its investigations in the development of new TL materials. However, to avoid underestimate or overestimation of the measured dose with the use of these materials, it should take into account it effective atomic number (Z eff ) it is well known that some TL materials considered as equivalent to the tissue, presents smaller TL intensity when being irradiated with low energy photons, while the TL material known as not equivalent to the tissue, they present the supra sensitivity effect for this radiation type. Nowadays, the estimate of the Z eff has not been clear, in this work the Z eff is determined by means of the traditional methods and an own method is presented for its determination. The results of the TL signal of different materials, when being irradiated with photons of effective energy between 24 keV and 1.25 MeV and their relationship with their calculated Z eff are also presented. (Author)

  3. Wallac automatic alarm dosimeter type RAD21

    International Nuclear Information System (INIS)

    Burgess, P. H.; Iles, W.J.

    1980-02-01

    The Automatic Alarm Dosimeter type RAD 21 is a batterypowered personal dosemeter and exposure rate alarm monitor, designed to be worn on the body, covering an exposure range from 0.1 to 999.9 mR and has an audible alarm which can be pre-set over the range 1 mR h -1 to 250 mR h -1 . The instrument is designed to measure x- and γ radiation over the energy range 50 keV to 3 MeV. The facilities and controls, the radiation, electrical, environmental and mechanical characteristics, and the manual, have been evaluated. (U.K.)

  4. An automatic evaluation system for NTA film neutron dosimeters

    CERN Document Server

    Müller, R

    1999-01-01

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

  5. TL and EPR dating: some applications

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, S. [Institute of Physics, University of Sao Paulo, Sao Paulo (Brazil)

    2006-07-01

    The intensity of thermoluminescence light emitted by a crystal is a function of radiation dose. The number of defects or of radicals in a crystal or organic substances is also a function of radiation dose. Since such defects or radicals present EPR signals, the EPR intensity is also a function of radiation dose. These facts are basis for radiation dosimetry and can be applied in dating of archaeological potteries or other materials, as well as in dating geological substances such as sediments, caves speleothemes, animal teeth and bones. Recent investigation on sensitized quartz based dosimeters and dating calcite covering ancient wall painting to find early settlers in Brazil will be presented. (Author)

  6. Thermoluminescence characteristics of Li2B4O7 single crystal dosimeters doped with Mn

    International Nuclear Information System (INIS)

    Ekdal, E.; Karalı, T.; Kelemen, A.; Ignatovych, M.; Holovey, V.; Harmansah, C.

    2014-01-01

    In this study, thermoluminescence (TL) characterization of newly developed Li 2 B 4 O 7 :Mn single crystal phosphor is reported. It is a very attractive material in personal dosimetry because of its near tissue equivalency (Z eff =7.25). The crystal was grown by the Czochralski method from high purity compounds. Glow curve, dose response, and fading and reproducibility properties of this material were investigated. Its TL glow curve showed two well separated peaks at about 105 and 220 °C with a heating rate of 2 °C s −1 . The main peak at 220 °C has a linear dose response of up to 60 Gy. The thermal fading ratio of the material is about 8% for the main peak in 10 days. The results showed that there is no significant variation of TL responses for 15 sequential measurements. Apart from the dosimetric properties above, the TL kinetic parameters of the main peak at 220 °C of Li 2 B 4 O 7 :Mn single crystal phosphor were also calculated using the various heating rates method. Activation energy and frequency factor were found as 1.21 eV and 3.75×10 11 s −1 , respectively. - Highlights: • Li 2 B 4 O 7 :Mn single crystal was investigated in terms of TL characteristics. • The material shows highly satisfactory dosimetric properties. • Various heating rates method was used for determining the kinetic parameter

  7. Liquid polymers for using in a holographic ionizing radiation dosimeter

    International Nuclear Information System (INIS)

    Nicolau-Rebigan, S.

    1979-01-01

    Some liquid polymeric systems for using in the holographic ionizing radiation dosimeter are presented. It is shown that the action of radiation on polymers leads to the destruction of the polymeric chains or to perform them, the both processes being applied in radiation dosimetry. Some advantages of the holographic dosimeter are outlined comparatively with those common used. (author)

  8. Performance improvement of pentacosa-diynoic acid label dosimeter for radiation processing technology

    Science.gov (United States)

    Abdel-Fattah, A. A.; Soliman, Y. S.

    2017-12-01

    A radiation sensitive material, 10,12-pentacosa-diynoic acid (PCDA), was incorporated into polyvinyl butyral (PVB) films to develop indicators/dosimeters for blood and food irradiation. The present study aims to improve the dosimetric performance of these previously prepared dosimeters and to extend their shelf life by the combination of a radical scavenger, propyl gallate (PG), and a UV absorber, tinuvin-p (TP). The X-ray diffraction (XRD) patterns of the dosimeters were analysed and their dosimetric characteristics were investigated by specular reflectance in the visible spectrum range of 400-700 nm. Upon irradiation, the films turn blue exhibiting two main bands around 670 and 620 nm. Their dose-response functions were fitted by a double exponential growth, 5 parameters, equation. Irradiation temperature influences the dosimeter response at 670 nm without causing thermochromic transition up to 50 °C in poly-PCDA. The useful dose range is 5-4000 Gy depending on the wavelengths of analysis and PCDA content in the films. The overall uncertainty of dose measurement is less than 6% at 2σ.

  9. Considerations in the application of the electronic dosimeter to dose of record

    International Nuclear Information System (INIS)

    Swinth, K.L.

    1997-12-01

    This report describes considerations for application of the electronic dosimeter (ED) as a measurement device for the dose of record (primary dosimetry). EDs are widely used for secondary dosimetry and advances in their reliability and capabilities have resulted in interest in their use to meet the needs of both primary and secondary dosimetry. However, the ED is an active device and more complex than the thermoluminescent and film dosimeters now in use for primary dosimetry. The user must evaluate the ED in terms of reliability, serviceability and radiations detected its intended application(s). If an ED is selected for primary dosimetry, the user must establish methods both for controlling the performance of the ED to ensure long term reliability of the measurements and for their proper use as a primary dosimeter. Regulatory groups may also want to develop methods to ensure adequate performance of the ED for dose of record. The purpose of the report is to provide an overview of considerations in the use of the ED for primary dosimetry. Considerations include recognizing current limitations, type testing of EDs, testing by the user, approval performance testing, calibration, and procedures to integrate the dosimeter into the users program

  10. Towards a new thickness-independent gamma radiation plastic film dosimeter

    International Nuclear Information System (INIS)

    Vieira, Marli Barbosa; Araujo, Patricia L.; Araujo, Elma S.

    2013-01-01

    A 100% national single-use gamma radiation plastic film dosimeter is presented in this work. A new approach for the development of this material allowed a step forward in the performance of poly (methyl metacrylate) films (PMMA) colored with bromothymol blue (BTB) acid-base indicator. We manage to improve dosimeter performance by introducing a gamma radiation insensitive dye to compensate film thickness variations. By doing so, we were able to obtain consistent dose-response correlations within a set of samples presenting 46 to 110 micrometers in thickness. Hence, our PMMA/BTB-P film dosimeter is suitable to measure absorbed dose in the 2-100kGy range even when film thickness undergoes more than 100% of variation. In addition, dose response data remain practically unaltered for four months after the exposure, when dosimeter films are kept in dark conditions and under refrigeration. The radiation effects on the optical properties were evaluated for Ultraviolet-Visible (UV-Vis) spectrophotometric analysis. Data of characteristic dose-response correlation in terms of changes in the maximum UV-Vis absorption due to radiation, and stability in time are also described. This potential new product is a promising tool for industrial radiation facilities, especially in gamma sterilization of medical supplies. (author)

  11. New colour centres in KCl:(Tl+ + Ca2+) and KCl:(Tl+ + Sr2+) crystals

    International Nuclear Information System (INIS)

    Ioan, A.; Topa, V.; Giurgea, M.

    1978-01-01

    Electrolytic colouring under unusual conditions (low temperature and high voltage) gives rise to the appearance of three new absorption bands peaking at 3.2, 2.5, and 1.7 eV and at 2.8, 2.1, and 1.5 eV in KCl:(Tl + + Ca 2+ ) and in KCl:(Tl + + Sr 2+ ) single crystals, respectively. The modifications of the absorption spectra of the coloured crystals induced by the application of a reversed electric field at the colouring temperature or by heat treatment are investigated. It is likely that the colour centre responsible for the new absorption bands is an aggregate centre which, besides an Tl - -complex, contains also at least an Ca(Sr) ion, a trapped electron, and an anionic vacancy. (author)

  12. Regional analysis of annual maximum rainfall using TL-moments method

    Science.gov (United States)

    Shabri, Ani Bin; Daud, Zalina Mohd; Ariff, Noratiqah Mohd

    2011-06-01

    Information related to distributions of rainfall amounts are of great importance for designs of water-related structures. One of the concerns of hydrologists and engineers is the probability distribution for modeling of regional data. In this study, a novel approach to regional frequency analysis using L-moments is revisited. Subsequently, an alternative regional frequency analysis using the TL-moments method is employed. The results from both methods were then compared. The analysis was based on daily annual maximum rainfall data from 40 stations in Selangor Malaysia. TL-moments for the generalized extreme value (GEV) and generalized logistic (GLO) distributions were derived and used to develop the regional frequency analysis procedure. TL-moment ratio diagram and Z-test were employed in determining the best-fit distribution. Comparison between the two approaches showed that the L-moments and TL-moments produced equivalent results. GLO and GEV distributions were identified as the most suitable distributions for representing the statistical properties of extreme rainfall in Selangor. Monte Carlo simulation was used for performance evaluation, and it showed that the method of TL-moments was more efficient for lower quantile estimation compared with the L-moments.

  13. Evaluation of coronary hemodynamics and exercise 201Tl-myocardial scintigraphy in patients with vasospastic angina

    International Nuclear Information System (INIS)

    Matsumura, Kentaro; Nakase, Emiko; Haiyama, Tohru; Hasegawa, Akira; Saito, Takayuki

    1992-01-01

    To clarify the coronary hemodynamics and myocardial perfusion in patients with vasospastic angina, we performed exercise 201 Tl-myocardial scintigraphy (planar and SPECT) in 72 patients and left coronary digital subtraction angiography (DSA) in 37 patients without significant organic coronary artery stenosis. Coronary artery spasm was documented by coronary angiography in all patients. Fifty-four patients (75%) developed exercise-induced 201 Tl-myocardial perfusion defect on SPECT. 201 Tl pulmonary uptake (L/H) was significantly increased in patients with vasospastic angina. Especially, L/H was higher in patients with multiple small perfusion defect on 201 Tl-SPECT, so that exercise-induced left ventricular dysfunction existed in patients with vasospastic angina and especially in cases of multiple small perfusion defect on 201 Tl-SPECT. The left coronary circulation time (CCT) was prolonged in patients with vasospastic angina. The mechanism of prolonged CCT is still unknown, but we suspected that prolonged CCT was induced by increased peripheral coronary vascular resistance in patients with vasospastic angina. It was concluded that the peripheral coronary circulation was disturbed in patients with vasospastic angina, but its abnormal coronary circulation had no relation to location of spasm-induced vessels. We concluded that impaired coronary microcirculation was taken a part of pathophysiology in vasospastic angina. (author)

  14. X-ray dosimetry of TlGaSe2 single crystals

    International Nuclear Information System (INIS)

    Kerimova, E.M.; Mustafaeva, S.N.; Mamedbeili, S.D.; Jabarov, J.N.; Iskenderova, P.M.; Kazimov, S.B.

    2002-01-01

    TlGaSe 2 compound belongs to group of layered semiconductors of A 3 B 3 C 2 6 -type. Photoelectric and optical properties of TlGaSe 2 single crystals were investigated in detail. Influence of gamma-, electron and neutron radiation on photoelectric properties of TlGaSe 2 single crystals is investigated too. The present work deals with experimental results relative to X-ray dosimetric characteristics of TlGaSe 2 crystals at 300 K. X-ray conductivity and X-ray dosimetric characteristic measurements are carried out in low load resistance regime. The source of X-ray radiation is the installation of X-ray diffraction analysis (URS-55a) with the BCV-2(Cu). Intensity of X-ray radiation (E) is regulated by measurement with current variation in tube at each given value of X-ray radiation dose E (R/min) are measured by crystal dosimeter DRGZ-02. X-ray conductivity coefficients K σ characterising X-ray sensitivity of investigated crystals are determined as the relative change of conductivity under X-ray radiation a per dose. There have been determined values of characteristic coefficients of TlGaSe 2 single crystal X-ray conductivity at different values of accelerating voltage (V a ) on the tube and corresponding doses of X-ray radiation. Analysis of obtained data showed that X-ray conductivity coefficients K σ in studied crystals are regularly decreased (from 0.276 to 0.033) as with the rise of dose (E=0.75-78.0 R/min) as with the increase of values of V a on X-ray tube (V a =254-50 keV). One of the possible reasons of observed regularities is that X-ray conductivity in investigated crystals, especially at comparatively low V a is due predominantly to radiation of thin layer of crystal. In this case with the rise of radiation intensity there have been started to prevail the mechanism of surface quadratic recombination which leads to observed decrease of X-ray conductivity. With the rise of accelerating potential 'effective hardness' is increased, as a result of which there

  15. Component resolved bleaching study in natural calcium fluoride using CW-OSL, LM-OSL and residual TL glow curves after bleaching

    International Nuclear Information System (INIS)

    Angeli, Vasiliki; Polymeris, George S.; Sfampa, Ioanna K.; Tsirliganis, Nestor C.; Kitis, George

    2017-01-01

    Natural calcium fluoride has been commonly used as thermoluminescence (TL) dosimeter due to its high luminescence intensity. The aim of this work includes attempting a correlation between specific TL glow curves after bleaching and components of linearly modulated optically stimulated luminescence (LM-OSL) as well as continuous wave OSL (CW-OSL). A component resolved analysis was applied to both integrated intensity of the RTL glow curves and all OSL decay curves, by using a Computerized Glow-Curve De-convolution (CGCD) procedure. All CW-OSL and LM-OSL components are correlated to the decay components of the integrated RTL signal, apart from two RTL components which cannot be directly correlated with either LM-OSL or CW-OSL component. The unique, stringent criterion for this correlation deals with the value of the decay constant λ of each bleaching component. There is only one, unique bleaching component present in all three luminescence entities which were the subject of the present study, indicating that each TL trap yields at least three different bleaching components; different TL traps can indicate bleaching components with similar values. According to the data of the present work each RTL bleaching component receives electrons from at least two peaks. The results of the present study strongly suggest that the traps that contribute to TL and OSL are the same. - Highlights: • A component resolved bleaching study was attempted to CaF_2:N in terms of CW-OSL, LM-OSL and RTL. • Bleaching decay constants originating from different TL peaks yield overlapping values. • Three to five individual components were used in order to describe the bleaching behavior in all luminescence entities. • There is only one, unique bleaching component present in all three luminescence entities.

  16. Copper interactions in TlCu7S4 and TlCu7Se4

    International Nuclear Information System (INIS)

    Noren, L.; Delaplane, R.G.; Berger, R.

    1999-01-01

    Complete text of publication follows. The copper chalcogenides ACu 7 S 4 (A=NH 4 + , Tl + , Rb + ) are quasi-one-dimensional metals at ambient and higher temperatures which is due to the high mobility of copper in these structures. TlCu 7 S 4 and TlCu 7 Se 4 are isostructural compounds, space group I4/m, which can be described on the basis of a TlX 8 cube with two different Cu sites, Cu(1) and Cu(2). Cu(2)-Cu(2) zigzag chains run along the c axis with only 3/4 occupation of the Cu(2) sites. However, these two compounds differ in behaviour on cooling. The sulphide shows a polymorphic first-order transition to the CsAg 7 S 4 type (P4/n) owing to ordering of the vacancies in the Cu(2)-Cu(2) chains. In order to study the nature of the Cu(2) order/disorder in the two title compounds, a series of neutron diffraction measurements (both Bragg and diffuse scattering) were made at several temperatures from 40 to 713 K on the instrument SLAD at Studsvik. The structure at each temperature was modelled using RMC techniques. The resulting configuration show that as the temperature increases, there is a marked increase in the mobility of the Cu atoms in the Cu(2)-Cu(2) chains for TlCu 7 S 4 but not for TlCu 7 Se 4 . This is due to the initial difference in the Cu(2)-Cu(2) distances, only 2.2A for the thiocuprate, but 2.7A in the selenocuprate which explains the relative ease for Cu(2) ordering in the latter case. (author)

  17. Insight on a novel layered semiconductors: CuTlS and CuTlSe

    Energy Technology Data Exchange (ETDEWEB)

    Aliev, Ziya S., E-mail: ziyasaliev@gmail.com [Institute of Catalysis and Inorganic Chemistry, ANAS, H.Javid ave. 113, AZ1143 Baku (Azerbaijan); Institute of Physics, ANAS, H.Javid ave. 131, AZ1143 Baku (Azerbaijan); Donostia International Physics Center (DIPC), 20080 San Sebastian (Spain); Zúñiga, Fco. Javier [Departamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao (Spain); Koroteev, Yury M. [Institute of Strength Physics and Materials Science, Russian Academy of Sciences, Siberian Branch, 634055 Tomsk (Russian Federation); Tomsk State University, Tomsk, 634050 (Russian Federation); Breczewski, Tomasz [Departamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao (Spain); Babanly, Nizamaddin B. [Institute of Catalysis and Inorganic Chemistry, ANAS, H.Javid ave. 113, AZ1143 Baku (Azerbaijan); Amiraslanov, Imamaddin R. [Institute of Physics, ANAS, H.Javid ave. 131, AZ1143 Baku (Azerbaijan); Politano, Antonio [Department of Physics, University of Calabria, 87036 Rende (CS) (Italy); Madariaga, Gotzon [Departamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao (Spain); Babanly, Mahammad B. [Institute of Catalysis and Inorganic Chemistry, ANAS, H.Javid ave. 113, AZ1143 Baku (Azerbaijan); and others

    2016-10-15

    Single crystals of the ternary copper compounds CuTlS and CuTlSe have been successfully grown from stoichiometric melt by using vertical Bridgman-Stockbarger method. The crystal structure of the both compounds has been determined by powder and single crystal X-Ray diffraction. They crystallize in the PbFCl structure type with two formula units in the tetragonal system, space group P4/nmm, a=3.922(2); c=8.123(6); Z=2 and a=4.087(6); c=8.195(19) Å; Z=2, respectively. The band structure of the reported compounds has been analyzed by means of full-potential linearized augmented plane-wave (FLAPW) method based on the density functional theory (DFT). Both compounds have similar band structures and are narrow-gap semiconductors with indirect band gap. The resistivity measurements agree with a semiconductor behavior although anomalies are observed at low temperature. - Graphical abstract: The crystal structures of CuTl and CuTlSe are isostructural with the PbFCl-type and the superconductor LiFeAs-type tetragonal structure. The band structure calculations confirmed that they are narrow-gap semiconductors with indirect band gaps of 0.326 and 0.083 eV. The resistivity measurements, although confirming the semiconducting behavior of both compounds exhibit unusual anomalies at low temperatures. - Highlights: • Single crystals of CuTlS and CuTlSe have been successfully grown by Bridgman-Stockbarger method. • The crystal structure of the both compounds has been determined by single crystal XRD. • The band structure of the both compounds has been analyzed based on the density functional theory (DFT). • The resistivity measurements have been carried out from room temperature down to 10 K.

  18. Thallium speciation in plant tissues-Tl(III) found in Sinapis alba L. grown in soil polluted with tailing sediment containing thallium minerals.

    Science.gov (United States)

    Krasnodębska-Ostręga, Beata; Sadowska, Monika; Ostrowska, Sylwia

    2012-05-15

    Besides the dominant species in plants-Tl(I), noticeable amounts of Tl(III) (about 10% of total Tl content) were found in extracts of plants cultivated in the presence of tailing sediments, which are the main source of anthropogenic thallium already present in the environment. It is an important step of gaining knowledge about the detoxification mechanisms developed by Sinapis alba. This plant species is highly tolerant to Tl and it is able to cumulate high amounts of Tl and transport it into the above-ground organs. For more adequate estimation of accumulating abilities of S. alba, the elements' bioavailability was taken into consideration. The obtained bioconcentration factors of Cd (AF=0.6) and Zn (AF=1-2) were significantly lower than of Tl (AF=100-200). The biomass production was similar to the biomass of control cultivation. The results were based on ICP MS measurements of total elements' content and HPLC ICP MS for speciation analysis. The quality of obtained results was evaluated based on the intermethod comparison with voltammetry as a reference method. Comparison of data obtained using ICP MS and electrochemical methods (after a proper chemical treatment) was also used for indication of Tl(III) presence and for proving that Tl(I) was not transferred into Tl(III) during analytical procedures. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Laser readable thermoluminescent radiation dosimeters and methods for producing thereof

    International Nuclear Information System (INIS)

    Braunlich, P.F.; Tetzlaff, W.

    1989-01-01

    Thin layer thermoluminescent radiation dosimeters for use in laser readable dosimetry systems, and methods of fabricating such thin layer dosimeters are disclosed. The thin layer thermoluminescent radiation dosimeters include a thin substrate made from glass or other inorganic materials capable of withstanding high temperatures and high heating rates. A thin layer of a thermoluminescent phosphor material is heat bonded to the substrate using an inorganic binder such as glass. The dosimeters can be mounted in frames and cases for ease in handling. Methods of the invention include mixing a suitable phosphor composition and binder, both being in particulate or granular form. The mixture is then deposited onto a substrate such as by using mask printing techniques. The dosimeters are thereafter heated to fuse and bond the binder and phosphor to the substrate. 34 figs

  20. Reactor Gamma Heat Measurements with Calorimeters and Thermoluminescence Dosimeters

    DEFF Research Database (Denmark)

    Haack, Karsten; Majborn, Benny

    1973-01-01

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

  1. Energy response study of modified CR-39 neutron personnel dosimeter

    International Nuclear Information System (INIS)

    Sathian, Deepa; Bakshi, A.K.; Datta, D.; Nair, Sreejith S.; Sathian, V.; Mishra, Jitendra; Sen, Meghnath

    2018-01-01

    Personnel neutron dosimetry is an integral part of radiation protection. No single dosimeter provides the satisfactory energy response, sensitivity, angular dependence characteristics and accuracy necessary to meet the requirement of an ideal personnel neutron dosimeter. The response of a personnel neutron dosimeter is critically dependent upon the energy distribution of the neutron field. CR-39 personnel neutron dosimeters were typically calibrated in the standard neutron field of 252 Cf and 241 Am-Be in our laboratory, although actual neutron fields may vary from the calibration neutron spectrum. Recently the badge cassette of the personnel neutron dosimeter was changed due to frequent damage of the PVC badge used earlier. This paper discusses energy response of CR-39 solid state nuclear track detector loaded in this modified badge cassette as per latest ISO recommendation

  2. Tl-201 per rectum scintigraphy in chronic liver disease: assessment of Tl-201 uptake indices

    International Nuclear Information System (INIS)

    Moon, Won Jin; Choi, Yun Young; Cho, Suk Shin; Lee, Min Ho

    1999-01-01

    Heart to liver ratio on Tl-201 per rectal scintigraphy (shunt index) is known to be useful in the assessment of portal systemic shunt. We assessed Tl-201 uptake pattern and early liver/heart uptake rate of Tl-201 and correlated with shunt index in patients with chronic active hepatitis (CAH) and liver cirrhosis (LC). Fifty eight patients with biopsy-proven chronic liver disease (35 with CAH, 23 with LC) underwent Tl-201 per rectum scintigraphy after instillation of 18.5 MBq of Tl-201 into the upper rectum. We evaluated hepatic uptake (type 1: homogeneous, 2: inhomogeneous segmental, 3: inhomogeneous nonsegmental) and extrahepatic uptake of spleen, heart and kidney (grade 0: no uptake, 1: less than liver, 2: equal to liver, 3: greater than liver). We measured the early liver/heart uptake rate (the slope of the liver to heart uptake ratio for 10 mim) and shunt index (heart to liver uptake ratio). Tl-201 uptake pattern and early liver/heart uptake rate of Tl-201 was correlated with the pathologic diagnosis and shunt index. Hepatic uptake patterns of type 1 and 2 were dominant in CAH (CAH: 27/35, LC: 8/23), and type 3 in LC (CAH: 8/35, LC: 15/23)(p<0.005). The grades of extrahepatic uptake were higher in LC than in CAH (spleen: p<0.001, other soft tissue: p<0.005). The early liver/heart uptake rate of CAH (0.110±0.111) was significantly higher than that of LC (0.014±0.090)(p<0.001). The sensitivity and specificity of the early liver/heart uptake rate were 77.7% and 67.7% in differentiating LC from CAH. There was negative correlation between early liver/heart uptake rate and shunt index (r=-0.3347, p<0.01). Hepatic and extrahepatic uptake pattern and early liver/heart uptake rate on Tl-201 per rectum scintigraphy are useful in the assessment of portal systemic shunt in patients with chronic liver disease

  3. Super-ionic conductivity in (1D) nanofibrous TlGaTe2

    International Nuclear Information System (INIS)

    Sardarly, R.M.; Samedov, O.A.; Abdullaev, A.P.; Salmanov, F.T.; Urbanovic, A.; Garet, F.; Coutaz, J.-L.

    2010-01-01

    Full text : Nanodimension topologic-disorder materials constitute an important feature in the development of modern electronics. Among such materials, TlGaTe 2 is a p-type semiconductor with a nanofibrous structure Ga 3 +Te 2 - 2 groups form chains extending along the c-axis of the material. These negatively charged chains are bonded together by Tl+ ions. The resulting tetragonal lattice is characterized by a 18 D4h group symmetry. Recently, much attention has been paid to systems that behave as if they had less than 3 spatial dimensions. Such materials are often called quasi-one-dimensional (1D) nanorods, nanofibrous or nanochains. It was already studied the temperature dependence of conductivity σ (T) and current-voltage (I-V) characteristics of TlGaTe 2 . In the ohmic region of the I -V curve, σ (T) exhibits a behavior typical of hopping conductivity, which can be modeled in the framework of the Mott approximation. Moreover, it was determined the values of the density of localized states, the activation energy, the hop lengths, and the difference between the energies of states and the concentration of deep traps. The abrupt variation of the I-V curve is ascribed to the Pool-Frenkel thermal-field effect, which allows to obtain the concentration of ionized centers, the free-path lengths, the Frenkel coefficients and the shape of the potential well of TlGaTe 2 . For T>300 K, TlGaTe 2 crystals present interesting nonlinear electrical behaviors, such as switching effects and a negative-differential-resistance (NDR) region in their S-type I-V characteristics. In the NDR region, self-excited oscillations of the voltage were also observed. Here, it was investigated the temperature dependence of TlGaTe 2 crystals conductivity σ (T) in two experimental geometries, i.e. parallel and perpendicularly to the tetragonal c-axis of the crystal. The observed sharp increase of TlGaTe 2 conductivity results from a strong change of the number of the high-mobility ions. The

  4. Impact of precursor purity on optical properties and radiation detection of CsI:Tl scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Saengkaew, Phannee; Cheewajaroen, Kulthawat; Yenchai, Chadet; Thong-aram, Decho [Chulalongkorn University, Department of Nuclear Engineering, Faculty of Engineering, Bangkok (Thailand); Sanorpim, Sakuntam [Chulalongkorn University, Department of Physics, Faculty of Science, Bangkok (Thailand); Jitpukdee, Manit [Kasetsart University, Department of Applied Radiation and Isotope, Faculty of Science, Bangkok (Thailand); Yordsri, Visittapong; Thanachayanont, Chanchana [Ministry of Science and Technology, National Metal and Materials Technology Center, National Science and Technology Development Agency, Pathumthani (Thailand); Nuntawong, Noppadon [Ministry of Science and Technology, National Electronic and Computer Technology Center, National Science and Technology Development Agency, Pathumthani (Thailand)

    2016-08-15

    Cesium iodide doped with thallium (CsI:Tl) crystals was grown to develop the gamma-ray detectors by using low-cost raw materials. Effect of impurities on optical properties and radiation detection performance was investigated. By a modified homemade Bridgman-Stockbarger technique, CsI:Tl samples were grown in two levels of CsI and TlI reactant materials, i.e., having as a very high purity of 99.999 % and a high purity of 99.9 %. XRD measurements indicate CsI:Tl crystals having a good quality with a dominant (110) plane. Having a cubic structure, a lattice constant of CsI crystals of 0.4574 nm and a crystallite size of 43.539 nm were obtained. From the lower-purity raw materials, calcite was found in an orange crystal with a lattice constant of 0.4560 nm and a crystallite size of 43.089 nm. By PL measurements, the optical properties of the CsI:Tl crystals were analyzed. ∝540-nm-wavelength PL peak was observed from the colorless high-purity crystal, and ∝600-nm-wavelength PL peak was observed from the orange crystal. The brighter PL emission was obtained from the orange crystals suggesting impurities. CsI:Tl surface morphology by SEM exhibited a smooth surface with some parallel crystal facets. For electrical properties of high-quality CsI:Tl crystals, the electrical resistances were 230 ± 16 MΩ in cross-sectional direction and 714 ± 136 MΩ in vertical direction with respect to more homogeneous crystal quality in cross-sectional direction than that in vertical direction. TEM measurement was applied to evaluate the microstructure of colorless CsI:Tl crystal with different patterns of a cubic structure. Both CsI:Tl crystals show good efficiencies and good resolutions. Maintaining the same electronic conditions and amplifications, the colorless CsI:Tl scintillators represented a higher detection efficiency at 122 keV of Co-57 of 78.4 % and the energy resolution of 23.3 % compared to the detection efficiency of 75.9 % and the energy resolution of 34.6 % of the

  5. Applicability of the Sunna dosimeter for food irradiation control

    International Nuclear Information System (INIS)

    Kovacs, A.; Baranyai, M.; Wojnarovits, L.; Miller, S.; Murphy, M.; McLaughlin, W.L.; Slezsak, I.; Kovacs, A.I.

    2002-01-01

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

  6. [AOR characterization and zoning: a dosimeter for blue light].

    Science.gov (United States)

    Dario, R; Uva, J; Di Lecce, V; Quarto, A

    2011-01-01

    The paper presents the results obtained thanks to an innovative experimental device for the assessment of artificial optical radiation (AOR) exposure in workplace. This . device was developed by 'Politecnico di Bari-DIASS'. The wearable personal dosimeter has three sensors: one is used for measuring head position/movement, therefore there is a color light sensor to determine the AOR and finally there is a video camera to localize sources. Our system is connected to a netbook via USB cable that allows one to obtain the real and extimated value of worker's exposure, also with "augmented reality". The aim of this paper is realizing work place safety zoning for the classifacation of not only specific dangerous areas through the analysis of overlapping information from the device.

  7. A new luminescence detection and stimulation head for the Risø TL/OSL reader

    International Nuclear Information System (INIS)

    Lapp, T.; Kook, M.; Murray, A.S.; Thomsen, K.J.; Buylaert, J.-P.; Jain, M.

    2015-01-01

    A new automated Detection And Stimulation Head (DASH) has been developed for the Risø TL/OSL luminescence reader to provide easy access to new technologies, new signals and new measurement methods. The automated DASH includes a filter changer and a detector changer that makes it possible to change stimulation filters (4 × 4 filter combinations possible) and detectors (3 detectors possible) as part of a measurements sequence. The new automated DASH with dedicated driver electronics does not affect the use of other attachments, and can be retrospectively fitted to existing Risø TL/OSL readers. - Highlights: • A new detection and stimulation head for the Risø TL/OSL reader is described. • An example of the use of the filter changer is presented. • The power and spatial uniformity of blue, green and IR stimulation are characterised. • The potential of an EMCCD camera detector is described.

  8. 207Pb and 205Tl NMR on Perovskite Type Crystals APbX3 (A = Cs, Tl, X = Br, I)

    Science.gov (United States)

    Sharma, Surendra; Weiden, Norbert; Weiss, Alarich

    1987-11-01

    By 205Tl and 207Pb NM R the chemical shift in polycrystalline samples of binary halides AX, BX2 and ternary halides ABX3 (A = Cs, Tl; B = Pb; X = Br, I) was studied at room temperature. The chemical shift tensors δ ( 205Tl) and δ (207Pb) were determined in magnitude and orientation on single crystals of the orthorhombic TlPbI3. The components of the δ(205Tl) tensor are δx (205Tl) || a = 611ppm; δy (205Tl) || b = 680 ppm; δZ(205Tl) || c = 1329 ppm; δiso(205Tl) = 873.3 ppm (with respect to 3.4 molar aqueous solution of TlOOCCH3). The chemical shift tensor of 207Pb in TlPbI3 shows two orientations. One of them is: δx (207Pb) = 3760 ppm, inclined 30° from b towards c, δy(207Pb) || a = 3485 ppm, δz(207Pb) = 2639 ppm inclined 120° from b towards c. δiso(207Pb) = 3295 ppm (with respect to saturated aqueous solution of Pb(NO3)2). The results are discussed with respect to the crystal structure and a model to explain orientation and anisotropy of the tensors δ(205Tl) and δ(207Pb) in TlPbI3 is proposed. In the system CsPbBr3-x Ix δ(207Pb) was studied on polycrystalline samples. The chemical shift increases with increasing x and negative excess shift is observed.

  9. 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)

  10. The TL dating of ancient porcelain

    International Nuclear Information System (INIS)

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

    1997-01-01

    The age determination of ancient porcelain using the pre-dose technique in TL dating was reported. The variation of beta dose with depth below the surface of the porcelain slice, the thermal activation characteristic (TAC) for 110 degree C peak, the measurement of paleodose and the estimation of annual dose were studied. The results show that this technique is suitable for authenticity testing of ancient porcelain, but both accuracy and precision for porcelain dating are worse than those for pottery, because porcelain differs from pottery on composition, structure and firing temperature. Besides, some complicated factors in the pre-dose technique would be the possible cause of the greater errors

  11. Prediction of Phase Separation of Immiscible Ga-Tl Alloys

    Science.gov (United States)

    Kim, Yunkyum; Kim, Han Gyeol; Kang, Youn-Bae; Kaptay, George; Lee, Joonho

    2017-06-01

    Phase separation temperature of Ga-Tl liquid alloys was investigated using the constrained drop method. With this method, density and surface tension were investigated together. Despite strong repulsive interactions, molar volume showed ideal mixing behavior, whereas surface tension of the alloy was close to that of pure Tl due to preferential adsorption of Tl. Phase separation temperatures and surface tension values obtained with this method were close to the theoretically calculated values using three different thermodynamic models.

  12. Characterization of cartilaginous tumors with 201Tl scintigraphy

    International Nuclear Information System (INIS)

    Higuchi, Takahiro; Taki, Junichi; Sumiya, Hisashi; Kinuya, Seigo; Nakajima, Kenichi; Tonami, Norihisa

    2005-01-01

    Histological diagnosis and grading of cartilaginous tumors are closely correlated with patient prognosis; consequently, they are essential elements. We attempted to clarify the characteristics of 201 Tl uptake in various histological types of cartilaginous tumors and to assess its clinical value. Twenty-two cases with histologically proven cartilaginous tumors (3 enchondromas, 15 conventional chondrosarcomas (grade I=9, II=5, III=1), 3 mesenchymal chondrosarcomas, and 1 de-differentiated chondrosarcoma) were examined retrospectively. Planar 201 Tl images were recorded 15 mm following intravenous injection of 201 Tl (111 MBq). 201 Tl uptake in the tumor was evaluated visually employing a five-grade scoring system: 0=no appreciable uptake, 1=faint uptake above the background level, 2=moderate uptake, 3=intense uptake but lower than heart uptake and 4=uptake higher than heart uptake. 201 Tl uptake scores were 0 in 3 of 3 enchondromas, 9 of 9 grade I, and 4 of 5 grade II conventional chondrosarcomas. 201 Tl uptake scores were 1 among 1 of 5 grades II and a grade III conventional chondrosarcoma. Mesenchymal chondrosarcoma and de-differentiated chondrosarcoma displayed 201 Tl uptake scores of 2 or 3. Absence of elevated 201 Tl uptake in cartilaginous tumors was indicative of enchondroma or low-grade conventional chondrosarcoma. However, in instances in which 201 Tl uptake is obvious, high-grade chondrosarcoma or variant types should be considered. (author)

  13. Methods, qualitative and quantitative evaluations of 201Tl myocardial scintiscans

    International Nuclear Information System (INIS)

    Buell, U.; Kleinhans, E.; Klepzig, M.; Seiderer, M.; Strauer, B.E.

    1981-01-01

    Exercise 201 Tl myocardial scintiscanning is a technique used to supplement exercise electrocardiography. The procedure employed should be identical to the standard procedure of electrocardiography. If the coronary disease has already been established by coronary angiography and kineventriculography, 201 Tl examinations should be carried out before surgery in order to determine the ''regional functional reserve''. Visual evaluations of the 201 Tl scintiscans should be supplemented by quantification methods. Quantification is also required between 201 Tl examination and surgery and to assure constant diagnostic accuracy in case of examination by different examiners. (orig./MG) [de

  14. Validation of an "Intelligent Mouthguard" Single Event Head Impact Dosimeter.

    Science.gov (United States)

    Bartsch, Adam; Samorezov, Sergey; Benzel, Edward; Miele, Vincent; Brett, Daniel

    2014-11-01

    Dating to Colonel John Paul Stapp MD in 1975, scientists have desired to measure live human head impacts with accuracy and precision. But no instrument exists to accurately and precisely quantify single head impact events. Our goal is to develop a practical single event head impact dosimeter known as "Intelligent Mouthguard" and quantify its performance on the benchtop, in vitro and in vivo. In the Intelligent Mouthguard hardware, limited gyroscope bandwidth requires an algorithm-based correction as a function of impact duration. After we apply gyroscope correction algorithm, Intelligent Mouthguard results at time of CG linear acceleration peak correlate to the Reference Hybrid III within our tested range of pulse durations and impact acceleration profiles in American football and Boxing in vitro tests: American football, IMG=1.00REF-1.1g, R2=0.99; maximum time of peak XYZ component imprecision 3.6g and 370 rad/s2; maximum time of peak azimuth and elevation imprecision 4.8° and 2.9°; maximum average XYZ component temporal imprecision 3.3g and 390 rad/s2. Boxing, IMG=1.00REF-0.9 g, R2=0.99, R2=0.98; maximum time of peak XYZ component imprecision 3.9 g and 390 rad/s2, maximum time of peak azimuth and elevation imprecision 2.9° and 2.1°; average XYZ component temporal imprecision 4.0 g and 440 rad/s2. In vivo Intelligent Mouthguard true positive head impacts from American football players and amateur boxers have temporal characteristics (first harmonic frequency from 35 Hz to 79 Hz) within our tested benchtop (first harmonic frequencyIntelligent Mouthguard qualifies as a single event dosimeter in American football and Boxing.

  15. A rapid alpha dosimeter for measuring nasal cavity wipe matter

    International Nuclear Information System (INIS)

    Tuo, Xianguo; Mu, Keliang; Zhong, Hongmei; Yang, Guoshan; Yuan, Yong

    2008-01-01

    Full text: It is necessary for people who work in the special condition to know whether the alpha radiation is inhaled through detecting quickly nasal cavity wipe matter. This measure method requires that the dosimeter must be portable and easy to operate, and be able to overcome some disadvantages, such as high environment background, few sample quantity, short measure time, and so on. Based on the above requests, a new intelligent portable system is developed for measuring alpha radiated degree, which is suitable for solid wiping matter detected of which diameter is smaller than 20 mm. This system is mainly made up of the detector, self- circumrotating sample shelf, I/A converter, signal gathering and processing system, power supply etc. The system chooses PIPS (Planar Implanted Passivated Silicon) detector which is a designed logical signal gathering hardware. The detector is with small volume, high efficiency and good resolution. PIPS detector doesn't need working gas and is easy to use compared with gas ionization chamber detector. The self-circumrotating sample shelf carries on measuring samples cubically and this improves the accuracy. The system uses compensating adjustment technology to remove background, automatically identify and compensate for radon, thoron and progeny interference, and is able to obtain the reliable measurement result. And the power for this system is supplied simultaneously by 220 V AV power and rechargeable Li-battery supply; it also has a mobile storage for more environments. The dosimeter is used to measure the samples of which diameters are 10∼20 mm , the result of tests shows that: detection efficiency ≥ 30%, background count ≤ 0.2 cpm, stability ≤ 0.3% / h, working temperature -10∼40 C degrees. The parameters of the system basically meet the rapid measurement in a special environment, so it has valuable application prospect in the field of environment, laboratories, and nuclear facilities etc. (author)

  16. Light scattering in optical CT scanning of Presage dosimeters

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-11-01

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

  17. Water-resistant alanine-EPR dosimeter alanpol

    International Nuclear Information System (INIS)

    Peimel-Stuglik, Zofia; Bryl-Sandelewska, Teresa; Mirkowski, Krzysztof; Sartowska, Bozena

    2009-01-01

    Alanpol-water-resistant alanine-electron paramagnetic resonance (EPR) dosimeter consisted of cheap DL-α-alanine (9.8-27%) suspended in polyethylene matrix was presented. The rods (O=2.8 mm) were extruded from a hot mixture of alanine and low-density polyethylene. No grinding or crushing was used for alanine preparation. An orientation of cylindrical crystals, up to 300 μm long in parallel to the rod axis was responsible for some differences in a shape of EPR signal. These differences had no negative consequences for dosimetric applications. Signal-to-dose dependence was linear up to 10 kGy. Standard deviation of dosimetric answer was up to ±1.8% and up to 2.4% for dosimeters with 9.8% and 27% of DL-α-alanine, respectively. Irradiation temperature coefficient for both dosimeters was equal 0.2%/ deg. C. Hydrophobic properties of polyethylene and small number of alanine crystals located on the surface of the rod led to high resistance of dosimeters to water and humidity. The 24 h soaking of irradiated dosimeters in liquid water-reduced EPR signals by 3-4% and by 2-3% for dosimeters with 27% and 9.8% of DL-α-alanine, respectively. Three month storage time of irradiated dosimeters in room conditions decreases EPR signal for ∼3%.

  18. Investigating On Colour Stability Conditions Of Postirradiation Radiochromic Film Dosimeter

    International Nuclear Information System (INIS)

    Nguyen Nguyet Dieu; Doan Binh; Pham Thu Hong; Cao Van Chung; Nguyen Thanh Duoc

    2011-01-01

    B3 dosimeter is a thin film with average thickness of 0.0194 mm, which is supplied by the Gex company, the United States. This dosimeter was influenced by many factors: light, temperature, humidity during and after irradiation process. In fact, B3 film dosimeters will be stable under certain conditions such as tightly sealed packs, controlled irradiation and stored temperature after irradiated. Therefore, investigation of the stability effect of postirradiated B3 film dosimeters on the heating temperature, heating time and storing time is carried out before the absorbed dose is read and followed standard reading procedures. When exposed to ionizing radiation, the dosimeters change from colorless to colour. The absorbed doses are read on a Genesys 20 spectrophotometer at a wavelength of 544 nm. Absorbed dose range is investigated from 0.55 to 80 kGy. Experimental results were indicated that colour stability of the postirradiated dosimeters at a temperature of 65 ± 3 o C for 30 minutes and keeping them in desiccator for 5 minutes before read out. Under these conditions, colour stability of B3 film dosimeter has maintained for 3 months. (author)

  19. Effect of thermal treatment on TL response of CaSO₄:Dy obtained using a new preparation method.

    Science.gov (United States)

    González, P R; Cruz-Zaragoza, E; Furetta, C; Azorín, J; Alcántara, B C

    2013-05-01

    We report the effect of thermal treatment on thermoluminescent (TL) sensitivity property of CaSO4:Dy obtained by a new preparation method at Instituto Nacional de Investigaciones Nucleares (ININ) of Mexico. Samples of phosphor powder were subjected to different thermal treatments respectively at 773, 873, 973 and 1,173K for 1h and then irradiated from 0.1 to 1,000 Gy gamma doses. Low energy dependence was analyzed too by irradiating with X-rays in the range of 16-145 keV. The results were normalized to the energy (1,252 keV) of (60)Co and they were compared with those obtained using the commercial dosimeters TLD-100. Also the kinetic parameters were determined by deconvolution of glow curve. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. New Generation of self-calibrated SS/EPR dosimeters: Alanine/EPR dosimeters

    International Nuclear Information System (INIS)

    Yordanov, N.D.; Gancheva, V.

    1999-01-01

    A new type of solid state/EPR dosimeters is described. Principally, it contains radiation sensitive diamagnetic material, some quantity of EPR active, but radiation insensitive, substance (for example Mn 2+ /MgO) and a binding material. In the present case alanine is used as a radiation sensitive substance. With this dosimeter, the EPR spectra of alanine and Mn 2+ are simultaneously recorded and the calibration graph represents the ratio of alanine versus Mn 2+ EPR signal intensity as a function of absorbed dose. In this way the reproducibility of the results is expected to be improved significantly including their intercomparison among different laboratories. Homogeneity of the prepared dosimeters and their behaviour (fading of EPR signals with time, influence of different meteorological conditions) show satisfactory reproducibility and stability with time. Because two different EPR active samples are recorded simultaneously, the influence of some instrument setting parameters (microwave power, modulation amplitude and modulation frequency) on the ratio I alanine /I Mn is also investigated. (author)

  1. p-MOSFET total dose dosimeter

    Science.gov (United States)

    Buehler, Martin G. (Inventor); Blaes, Brent R. (Inventor)

    1994-01-01

    A p-MOSFET total dose dosimeter where the gate voltage is proportional to the incident radiation dose. It is configured in an n-WELL of a p-BODY substrate. It is operated in the saturation region which is ensured by connecting the gate to the drain. The n-well is connected to zero bias. Current flow from source to drain, rather than from peripheral leakage, is ensured by configuring the device as an edgeless MOSFET where the source completely surrounds the drain. The drain junction is the only junction not connected to zero bias. The MOSFET is connected as part of the feedback loop of an operational amplifier. The operational amplifier holds the drain current fixed at a level which minimizes temperature dependence and also fixes the drain voltage. The sensitivity to radiation is made maximum by operating the MOSFET in the OFF state during radiation soak.

  2. Guidelines for the calibration of personnel dosimeters

    International Nuclear Information System (INIS)

    Roberson, P.L.; Holbrook, K.L.

    1984-01-01

    This guide describes minimum acceptable performance levels for personnel dosimetry systems used at Department of Energy (DOE) facilities. The goal is to improve both the quality of radiological calibrations and the methods of comparing reported occupational doses between DOE facilities. Reference calibration techniques are defined. A standard for evaluation of personnel dosimetry systems and recommended design parameters for personnel dosimeters are also included. Approximate intervals for the radiation energies for which these guidelines are appropriate are 15 keV to 2 MeV for photons; above 0.3 MeV for beta particles; and 1 keV to 2 MeV for neutrons. An analysis of ANSI N13.11 was completed using performance evaluations of selected personnel dosimetry systems in use at DOE facilities. The results of this analysis are incorporated in the guidelines

  3. Study of an individual neutron dosimeter

    International Nuclear Information System (INIS)

    Debeauvais, M.; Tripier, J.

    1976-01-01

    A dosimeter using Kodak LR 115 cellulose nitrate as detecting material was designed. It serves to determine 3 neutron energy ranges. The 6 Li(n,α)t reaction is used for the thermal region, the sensitivity being 0.2mrads to 1 rad for neutron energies between thermal and 0.05eV. The same reaction defines the 0.05eV to 1000eV energy range but the detection system is placed inside a cadmium screen; the sensitivity is 0.2 to 500rads. Finally above 1MeV the neutron reactions used are those on the detector components themselves, i.e. elastic collisions and (nα) reactions on carbon, nitrogen and oxygen nuclei. Detection is possible between 0.7 and 700 rads [fr

  4. SU-E-T-749: Thorough Calibration of MOSFET Dosimeters

    International Nuclear Information System (INIS)

    Plenkovich, D; Thomas, J

    2015-01-01

    Purpose: To improve the accuracy of the MOSFET calibration procedure by performing the measurement several times and calculating the average value of the calibration factor for various photon and electron energies. Methods: The output of three photon and six electron beams of Varian Trilogy linear accelerator SN 5878 was calibrated. Five reinforced standard sensitivity MOSFET dosimeters were placed in the calibration jig and connected to the Reader Module. As the backscatter material was used 7 cm of Virtual Water. The MOSFET dosimeters were covered with 1.5 cm thick bolus for the regular and SRS 6 MV beams, 3 cm bolus for 15 MV beam, 1.5 cm bolus for 6 MeV electron beam, and 2 cm bolus for the electron energies of 9, 12, 15, 18, and 22 MeV. The dosimeters were exposed to 100 MU, and the calibration factor was determined using the mobileMOSFET software. To improve the accuracy of calibration, this procedure was repeated ten times and the calibration factors were averaged. Results: As the number of calibrations was increasing the variability of calibration factors of different dosimeters was decreasing. After ten calibrations, the calibration factors for all five dosimeters were within 1% of one another for all energies, except 6 MV SRS photons and 6 MeV electrons, for which the variability was 2%. Conclusions: The described process results in calibration factors which are almost independent of modality or energy. Once calibrated, the dosimeters may be used for in-vivo dosimetry or for daily verification of the beam output. Measurement of the radiation dose under bolus and scatter to the eye are examples of frequent use of calibrated MOSFET dosimeters. The calibration factor determined for full build-up is used under these circumstances. To the best of our knowledge, such thorough procedure for calibrating MOSFET dosimeters has not been reported previously. Best Medical Canada provided MOSFET dosimeters for this project

  5. NaI(Tl) response functions

    International Nuclear Information System (INIS)

    Vega C, H. R.; Ortiz R, J. M.; Benites R, J. L.; De Leon M, H. A.

    2015-09-01

    The response functions of a NaI(Tl) detector have been estimated using Monte Carlo methods. Response functions were calculated for monoenergetic photon sources (0.05 to 3 MeV). Responses were calculated for point-like sources and for sources distributed in Portland cement cylinders. The responses were used to calculate the efficiency functions in term of photon energy. Commonly, sources used for calibration are point-like, and eventually sources to be measured have different features. In order to use the calibrated sources corrections due to solid angle, self-absorption and scattering, must be carried out. However, some of these corrections are not easy to perform. In this work, the calculated responses were used to estimate the detector efficiency of point-like sources, and sources distributed in Portland type cement. Samples of Portland paste were prepared and were exposed to photoneutrons produced by a 15 MV linac. Some of the elements in the cement were activated producing γ-emitting radionuclides that were measured with a NaI(Tl) gamma-ray spectrometer, that was calibrated with point-like sources. In order to determine the specific activity in the induced radioisotopes calculated efficiencies were used to make corrections due to the differences between the solid angle, photon absorption and photon scattering in the point-like calibration sources and the sources distributed in cement. During the interaction between photoneutrons and the cement samples three radioisotopes were induced: 56 Mn, 24 Na, and 28 Al. (Author)

  6. Organic liquids as ''activ media'' in a holographic ionizing radiation dosimeter

    International Nuclear Information System (INIS)

    Nicolau-Rebigan, S.

    1979-01-01

    Some types of organic liquids for using as activ media in a holographic ionizing radiation dosimeter are presented. One outlined the advantages of the holographic dosimeter comparatively with those of common used dosimeters. One presented the advantages of utilization of the organic liquids comparatively with another chemical systems used in a holographic ionizing radiation dosimeter. (author)

  7. Design of calibration method in neutron and individual dosimeter

    International Nuclear Information System (INIS)

    Belkhodia, M.

    1984-12-01

    Usually albedo dosemeters are calibrated with beam of monoenergetic neutrons. Since neutron energy around neutron sources varies greatly, we applied the calibration method to a mixed field whose energy spectrum lies between 0.025 ev and 10 Mev. The method is based on a mathematical model that deals with the dosimeter response as a function at the neutron energy. The measurements carried out with solid state nuclear track detectors show the dosimeter practical aspect. The albedo dosimeter calibration gave results on good agreement with the international institution recommendations

  8. Polymer gel dosimeter with AQUAJOINT® as hydrogel matrix

    Science.gov (United States)

    Maeyama, Takuya; Ishida, Yasuhiro; Kudo, Yoshihiro; Fukasaku, Kazuaki; Ishikawa, Kenichi L.; Fukunishi, Nobuhisa

    2018-05-01

    We report a polymer gel dosimeter based on a new gel matrix (AQUAJOINT®) that is a thermo-irreversible hydrogel formed by mixing two types of water-based liquids at room temperature. Normoxic N-vinylpyrrolidone-based polymer gels were prepared with AQUAJOINT® instead of gelatin. This AQUAJOINT®-based gel dosimeter exhibits a 2.5-fold increase in sensitivity over a gelatin-based gel dosimeter and a linear dose-response in the dose range of 0-8 Gy. This gel has heat resistance in a jar and controlled gel properties such as viscoelastic and mechanical characters, which may be useful for deformable polymer gel dosimetry.

  9. Alanine EPR dosimeter response in proton therapy beams

    International Nuclear Information System (INIS)

    Gall, K.; Serago, C.; Desrosiers, M.; Bensen, D.

    1997-01-01

    We report a series of measurements directed to assess the suitability of alanine as a mailable dosimeter for dosimetry quality assurance of proton radiation therapy beams. These measurements include dose-response of alanine at 140 MeV, and comparison of response vs energy with a parallel plate ionization chamber. All irradiations were made at the Harvard Cyclotron Laboratory, and the dosimeters were read at NIST. The results encourage us that alanine could be expected to serve as a mailable dosimeter with systematic error due to differential energy response no greater than 3% when doses of 25 Gy are used. (Author)

  10. Investigation of self-indicating radiation personal dosimeter

    International Nuclear Information System (INIS)

    Xia Wen; Ye Honsheng; Lin Min; Xu Lijun; Chen Kesheng; Chen Yizhen

    2014-01-01

    A self-indicating radiation personal dosimeter was investigated using radiation sensitive material diacetylene monomer PCDA, which was a component of the polymerization system. The substrate material, solvent, sensitive material, solution temperature, thickness of film and the preparation method were studied. The dosimeter colour changes from white to blue when exposed 0.1-2.5 Gy, and the linearly dependent coefficient of the exposure response is 0.9998, the stability of absorbency in two weeks after exposure is testified well. It can be used as self-indicating radiation alert personal dosimeter. (authors)

  11. Measurement of extremely low level dose with LiF(Mg,Cu,P) TL chips

    International Nuclear Information System (INIS)

    Zha Ziying; Wang Shoushan; Wu Fang; Chen Guolong; Li Yuanfang; Zhu Jianhuan

    1986-01-01

    This paper presents some of the dosimetric characteristics of newly developed LiF(Mg,Cu,P) TL chips with high signal-to-noise ratio for measurement at the 10 -7 to 10 -4 Gy dose level. Measuring techniques and optimum procedures for annealing and readout are also presented. (author)

  12. Personal noise dosimeters: Accuracy and reliability in varied settings

    Directory of Open Access Journals (Sweden)

    Sheri Lynn Cook-Cunningham

    2014-01-01

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

  13. [Tl(III)(dota)](-): An Extraordinarily Robust Macrocyclic Complex.

    Science.gov (United States)

    Fodor, Tamás; Bányai, István; Bényei, Attila; Platas-Iglesias, Carlos; Purgel, Mihály; Horváth, Gábor L; Zékány, László; Tircsó, Gyula; Tóth, Imre

    2015-06-01

    The X-ray structure of {C(NH2)3}[Tl(dota)]·H2O shows that the Tl(3+) ion is deeply buried in the macrocyclic cavity of the dota(4-) ligand (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) with average Tl-N and Tl-O distances of 2.464 and 2.365 Å, respectively. The metal ion is directly coordinated to the eight donor atoms of the ligand, which results in a twisted square antiprismatic (TSAP') coordination around Tl(3+). A multinuclear (1)H, (13)C, and (205)Tl NMR study combined with DFT calculations confirmed the TSAP' structure of the complex in aqueous solution, which exists as the Λ(λλλλ)/Δ(δδδδ) enantiomeric pair. (205)Tl NMR spectroscopy allowed the protonation constant associated with the protonation of the complex according to [Tl(dota)](-) + H(+) ⇆ [Tl(Hdota)] to be determined, which turned out to be pK(H)Tl(dota) = 1.4 ± 0.1. [Tl(dota)](-) does not react with Br(-), even when using an excess of the anion, but it forms a weak mixed complex with cyanide, [Tl(dota)](-) + CN(-) ⇆ [Tl(dota)(CN)](2-), with an equilibrium constant of Kmix = 6.0 ± 0.8. The dissociation of the [Tl(dota)](-) complex was determined by UV-vis spectrophotometry under acidic conditions using a large excess of Br(-), and it was found to follow proton-assisted kinetics and to take place very slowly (∼10 days), even in 1 M HClO4, with the estimated half-life of the process being in the 10(9) h range at neutral pH. The solution dynamics of [Tl(dota)](-) were investigated using (13)C NMR spectroscopy and DFT calculations. The (13)C NMR spectra recorded at low temperature (272 K) point to C4 symmetry of the complex in solution, which averages to C4v as the temperature increases. This dynamic behavior was attributed to the Λ(λλλλ) ↔ Δ(δδδδ) enantiomerization process, which involves both the inversion of the macrocyclic unit and the rotation of the pendant arms. According to our calculations, the arm-rotation process limits the Λ(λλλλ) ↔

  14. Evaluation of LLNL's Nuclear Accident Dosimeters at the CALIBAN Reactor September 2010

    International Nuclear Information System (INIS)

    Hickman, D.P.; Wysong, A.R.; Heinrichs, D.P.; Wong, C.T.; Merritt, M.J.; Topper, J.D.; Gressmann, F.A.; Madden, D.J.

    2011-01-01

    The Lawrence Livermore National Laboratory uses neutron activation elements in a Panasonic TLD holder as a personnel nuclear accident dosimeter (PNAD). The LLNL PNAD has periodically been tested using a Cf-252 neutron source, however until 2009, it was more than 25 years since the PNAD has been tested against a source of neutrons that arise from a reactor generated neutron spectrum that simulates a criticality. In October 2009, LLNL participated in an intercomparison of nuclear accident dosimeters at the CEA Valduc Silene reactor (Hickman, et.al. 2010). In September 2010, LLNL participated in a second intercomparison of nuclear accident dosimeters at CEA Valduc. The reactor generated neutron irradiations for the 2010 exercise were performed at the Caliban reactor. The Caliban results are described in this report. The procedure for measuring the nuclear accident dosimeters in the event of an accident has a solid foundation based on many experimental results and comparisons. The entire process, from receiving the activated NADs to collecting and storing them after counting was executed successfully in a field based operation. Under normal conditions at LLNL, detectors are ready and available 24/7 to perform the necessary measurement of nuclear accident components. Likewise LLNL maintains processing laboratories that are separated from the areas where measurements occur, but contained within the same facility for easy movement from processing area to measurement area. In the event of a loss of LLNL permanent facilities, the Caliban and previous Silene exercises have demonstrated that LLNL can establish field operations that will very good nuclear accident dosimetry results. There are still several aspects of LLNL's nuclear accident dosimetry program that have not been tested or confirmed. For instance, LLNL's method for using of biological samples (blood and hair) has not been verified since the method was first developed in the 1980's. Because LLNL and the other DOE

  15. The response of different types of TL lithium fluoride detectors to high-energy mixed radiation fields

    Energy Technology Data Exchange (ETDEWEB)

    Obryk, B. [Institute of Nuclear Physics PAN (IFJ), ul. Radzikowskiego 152, 31-342 Krakow (Poland)], E-mail: barbara.obryk@ifj.edu.pl; Bilski, P.; Budzanowski, M. [Institute of Nuclear Physics PAN (IFJ), ul. Radzikowskiego 152, 31-342 Krakow (Poland); Fuerstner, M. [CERN - European Organization for Nuclear Research, 1211 Geneva 23 (Switzerland); Ilgner, C. [CERN - European Organization for Nuclear Research, 1211 Geneva 23 (Switzerland) and University of Dortmund, Dortmund (Germany); Jaquenod, F. [Ecole d' Ingenieurs de Geneve, Geneva (Switzerland); Olko, P.; Puchalska, M. [Institute of Nuclear Physics PAN (IFJ), ul. Radzikowskiego 152, 31-342 Krakow (Poland); Vincke, H. [CERN - European Organization for Nuclear Research, 1211 Geneva 23 (Switzerland)

    2008-02-15

    Thermoluminescent (TL) dosimeters are routinely used to monitor absorbed doses in many kinds of radiation fields which contain photons, electrons and neutrons. However, TLDs are mainly calibrated to photon sources. We studied the response of TLDs to complex secondary fields arising during the operation of high-energy accelerators (e.g. the Large Hadron Collider (LHC) at CERN). The experiments were conducted at the CERN-EU high-energy reference field facility (CERF). Six different LiF-based TLDs (MTS-N, MTS-7, MTS-6, MCP-N, MCP-7, MCP-6) were exposed to various secondary CERF's fields (both for high and low doses), by placing them at various positions: at the target and concrete top and side positions. For the experiment at the target the corresponding Monte Carlo calculations were also carried out using the FLUKA transport code and compared with experimental results. In addition, alanine dosimeters were used as an independent reference. The results show that TLDs are well suited for monitoring radiation fields around the LHC. Nevertheless, further investigations are required, some of which are in progress.

  16. Phytotoxicity of thallium (Tl) in culture solution. Pt. 1. Effects of Tl(I) on the growth and heavy metal contents of pea and field bean plants

    Energy Technology Data Exchange (ETDEWEB)

    Poetsch, U; Austenfeld, F A

    1985-01-01

    The effects of TlNO/sub 3/ and Tl(I)EDTA on growth and heavy metal contents of pea plants and field bean plants were compared in hydroponic culture experiments. In the presence of TlNO/sub 3/, the essential heavy metals were available to the plants in their ionic forms. When Tl(I)EDTA was present the essential heavy metals were available as chelated complexes. With increasing concentration of TlNO/sub 3/ dry matter production of pea plants was lowered and the Tl content of each organ was increased. The highest Tl content was found within the stems. The increased Tl contents were accompanied by depressed Mn, Zn, and Cu contents of the roots and depressed Mn contents of the stems, but increased Fe contents of the stems. Substitution of TlNO/sub 3/ by Tl(I)EDTA resulted in a stronger growth inhibition of the pea plants, and higher Tl contents of each organ. The highest Tl content was found within the stems. Tl(I)EDTA depressed Mn in the roots, but increased Fe and Mn in the stems, and Fe, Zn and Cu in the leaves. The increases may due to concentration by growth inhibition. The growth of the field bean was not effected by TlNO/sub 3/ nor by Tl(I)EDTA. The field bean contained most of the Tl within the roots and translocated only relatively small amounts to the shoots. This pattern was independent of the Tl compound. Increasing concentrations of TlNO/sub 3/ resulted in depressed Mn and Zn contents of the roots, and Mn contents of the stems. Chelation of Tl(I) resulted in a decrease of the Tl content of each organ. Tl(I)EDTA depressed only the Mn content of the roots.

  17. Assessment of FIV-C infection of cats as a function of treatment with the protease inhibitor, TL-3

    Directory of Open Access Journals (Sweden)

    de Rozières Sohela

    2004-11-01

    Full Text Available Abstract Background The protease inhibitor, TL-3, demonstrated broad efficacy in vitro against FIV, HIV and SIV (simian immunodeficiency virus, and exhibited very strong protective effects on early neurologic alterations in the CNS of FIV-PPR infected cats. In this study, we analyzed TL-3 efficacy using a highly pathogenic FIV-C isolate, which causes a severe acute phase immunodeficiency syndrome, with high early mortality rates. Results Twenty cats were infected with uncloned FIV-C and half were treated with TL-3 while the other half were left untreated. Two uninfected cats were used as controls. The general health and the immunological and virological status of the animals was monitored for eight weeks following infection. All infected animals became viremic independent of TL-3 treatment and seven of 20 FIV-C infected animals developed severe immunodepletive disease in conjunction with significantly (p ≤ 0.05 higher viral RNA loads as compared to asymptomatic animals. A marked and progressive increase in CD8+ T lymphocytes in animals surviving acute phase infection was noted, which was not evident in symptomatic animals (p ≤ 0.05. Average viral loads were lower in TL-3 treated animals and of the 6 animals requiring euthanasia, four were from the untreated cohort. At eight weeks post infection, half of the TL-3 treated animals and only one of six untreated animals had viral loads below detection limits. Analysis of protease genes in TL-3 treated animals with higher than average viral loads revealed sequence variations relative to wild type protease. In particular, one mutant, D105G, imparted 5-fold resistance against TL-3 relative to wild type protease. Conclusions The findings indicate that the protease inhibitor, TL-3, when administered orally as a monotherapy, did not prevent viremia in cats infected with high dose FIV-C. However, the modest lowering of viral loads with TL-3 treatment, the greater survival rate in symptomatic animals of

  18. Leading the Charge for SoTL--Embracing Collaboration

    Science.gov (United States)

    Cassard, Anita; Sloboda, Brian

    2014-01-01

    The scholarship of teaching and learning (SoTL) enables colleges and universities to assess student learning and measure the outcomes by engaging in meaningful research, and to disseminate this research. The objective of this paper is to give a snapshot of and assess the current thinking behind this scholarship by presenting examples of SoTL, and…

  19. Abnormal 201Tl limb scan due to unilateral tremor

    International Nuclear Information System (INIS)

    Simons, M.; Schelstraete, K.; Bratzlavsky, M.

    1982-01-01

    A abnormal intra- and interextremity distribution pattern on 201 Tl was observed on the limb scan of a patient with a unilateral tremor. This is ascribed to the increased blood flow in the muscles responsible for the tremor. The suggestion is made that the existence of tremor should be considered as a possible explanation for unexpected abnormalities on 201 Tl limb scintigrams

  20. Kinetic parameters and TL mechanism in cadmium tetra borate phosphor

    International Nuclear Information System (INIS)

    Annalakshmi, O.; Jose, M.T.; Sridevi, J.; Venkatraman, B.; Amarendra, G.; Mandal, A.B.

    2014-01-01

    Polycrystalline powder samples of cadmium tetra borate were synthesized by a simple solid state sintering technique and gamma irradiated sample showed a simple Thermoluminescence (TL) glow peak around 460 K. The TL kinetic parameters of gamma irradiated phosphor were determined by initial rise (IR), isothermal decay (ID), peak shape (PS), variable heating rate (VHR) and glow curve de-convolution method. The kinetic parameters such as activation energy (E), frequency factor (s) and order of kinetics (b) were calculated by IR, ID, PS and VHR methods are in the order of ∼1.05 eV, 10 9 –10 12 s −1 and 1.58, respectively. From the results of TL and PL emission studies carried out on the phosphor revealed that the defect centers related to TL is different from that for PL. EPR measurements were carried out to identify the defect centers formed in cadmium tetra borate phosphor on gamma irradiation. Based on EPR studies the mechanism for TL process in cadmium tetra borate is proposed in this paper -- Highlights: • Polycrystalline powder samples of undoped cadmium tetra borate synthesized. • Cadmium tetra borate phosphor exhibits a dosimetric peak at 458 K. • Kinetic parameters of the trap responsible for TL evaluated. • TL mechanism is proposed from TL to EPR correlation studies

  1. Kinetic parameters and TL mechanism in cadmium tetra borate phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Annalakshmi, O. [Radiological Safety Division, Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Jose, M.T., E-mail: mtj@igcar.gov.in [Radiological Safety Division, Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Sridevi, J. [Central Leather Research Institute, Council of Scientific and Industrial Research, Chennai 600 020, Tamilnadhu (India); Venkatraman, B. [Radiological Safety Division, Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Amarendra, G. [Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Mandal, A.B. [Central Leather Research Institute, Council of Scientific and Industrial Research, Chennai 600 020, Tamilnadhu (India)

    2014-03-15

    Polycrystalline powder samples of cadmium tetra borate were synthesized by a simple solid state sintering technique and gamma irradiated sample showed a simple Thermoluminescence (TL) glow peak around 460 K. The TL kinetic parameters of gamma irradiated phosphor were determined by initial rise (IR), isothermal decay (ID), peak shape (PS), variable heating rate (VHR) and glow curve de-convolution method. The kinetic parameters such as activation energy (E), frequency factor (s) and order of kinetics (b) were calculated by IR, ID, PS and VHR methods are in the order of ∼1.05 eV, 10{sup 9}–10{sup 12} s{sup −1} and 1.58, respectively. From the results of TL and PL emission studies carried out on the phosphor revealed that the defect centers related to TL is different from that for PL. EPR measurements were carried out to identify the defect centers formed in cadmium tetra borate phosphor on gamma irradiation. Based on EPR studies the mechanism for TL process in cadmium tetra borate is proposed in this paper -- Highlights: • Polycrystalline powder samples of undoped cadmium tetra borate synthesized. • Cadmium tetra borate phosphor exhibits a dosimetric peak at 458 K. • Kinetic parameters of the trap responsible for TL evaluated. • TL mechanism is proposed from TL to EPR correlation studies.

  2. A pocket warning γ-dosimeter with numerical display

    International Nuclear Information System (INIS)

    Jones, A.R.

    1980-09-01

    A pocket warning dosimeter is described. It provides alarms (continuous tone and a flashing red light) when a presettable dose has been accumulated in the range .064 - 16.4 rads (0.64 - 164 μGy). This warning level can be selected in nine steps of 2 with a switch inside the dosimeter. The dose rate is indicated by a series of sound pulses whose repetition rate is proportional to the dose rate. At 1 rad/h (10 mGy/h) about 17 pluses/minute are emitted. The accumulated dose up to 20 rads (0.2 Gy) is displayed in steps of 1 mrad (10 μGy) with a liquid crystal display. A red LED lights before battery failure occurs. The effects of changes in temperature, battery voltage, dose rate and photon energy upon dosimeter sensitivity are presented. Finally, the applications of the dosimeter are discussed. (auth)

  3. UVB DNA dosimeters analyzed by polymerase chain reactors

    International Nuclear Information System (INIS)

    Yoshida, Hiroko; Regan, J.D.; Florida Inst. of Tech., Melbourne, FL

    1997-01-01

    Purified bacteriophage λ DNA was dried on a UV-transparent polymer film and served as a UVB dosimeter for personal and ecological applications. Bacteriophage λ DNA was chosen because it is commercially available and inexpensive, and its entire sequence is known. Each dosimeter contained two sets of DNA sandwiched between UV-transparent polymer films, one exposed to solar radiation (experimental) and another protected from UV radiation by black paper (control). The DNA dosimeter was then analyzed by a polymerase chain reaction (PCR) that amplifies a 500 base pair specific region of λ DNA. Photoinduced damage in DNA blocks polymerase from synthesizing a new strand; therefore, the amount of amplified product in UV-exposed DNA was reduced from that found in control DNA. The dried λ DNA dosimeter is compact, robust, safe and transportable, stable over long storage times and provides the total UVB dose integrated over the exposure time. (author)

  4. Limitations of commonly used thick-element personal dosimeters

    International Nuclear Information System (INIS)

    Gupta, V.P.

    1983-01-01

    In the ANSI Standard N13.11, accepted in June 1982, radiation dose depths of 1.0 cm and 0.007 cm in tissue for protection dosimetry have been adopted for deep and shallow dose equivalent estimations respectively. This standard is presently used for a mandatory personnel dosimetry performance testing program in the United States. Estimation of shallow-dose equivalent using a two-element dosimeter is described under the guidelines of this standard and the dosimetry practices followed by most dosimeter processors. A mathematical formulation, correlating a dosimeter response and shallow-dose equivalent factors at different energies, is presented. Also, the performance of a two-element thermoluminescent dosimeter is examined and the shallow-dose equivalent response results, both for the beta particles and photons, are discussed

  5. Temperature, humidity and time. Combined effects on radiochromic film dosimeters

    DEFF Research Database (Denmark)

    Abdel-Fattah, A.A.; Miller, A.

    1996-01-01

    The effects of both relative humidity and temperature during irradiation on the dose response of FWT-60-00 and Riso B3 radiochromic film dosimeters have been investigated in the relative humidity (RH) range 11-94% and temperature range 20-60 degrees C for irradiation by Co-60 photons and 10-Me......V electrons. The results show that humidity and temperature cannot be treated as independent variables, rather there appears to be interdependence between absorbed dose, temperature, and humidity. Dose rate does not seem to play a significant role. The dependence of temperature during irradiation is +0.......25 +/- 0.1% per degrees C for the FWT-60-00 dosimeters and +0.5 +/- 0.1% per degrees C For Riso B3 dosimeters at temperatures between 20 and 50 degrees C and at relative humidities between 20 and 53%. At extreme conditions both with respect to temperature and to humidity, the dosimeters show much stronger...

  6. Comparison of the effectiveness of polymer gel dosimeters (Magic ...

    African Journals Online (AJOL)

    demonstrate that the gel dosimeters are best suited for nuclear medicine. Keywords: Magic ... International Pharmaceutical Abstract, Chemical Abstracts, Embase, Index Copernicus, EBSCO, African. Index Medicus .... Reaction rate. 2.15E-6.

  7. Antioxidant effect of green tea on polymer gel dosimeter

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  8. Feasibility study of a photoconductor based dosimeter for quality assurance in radiotherapy

    Science.gov (United States)

    Lee, Y. K.; Kim, S. W.; Kim, J. N.; Kang, Y. N.; Kim, J. Y.; Lee, D. S.; Kim, K. T.; Han, M. J.; Ahn, K. J.; Park, S. K.

    2017-09-01

    With the recent market entries of new types of linear accelerators (LINACs) with a multi leaf collimator (MLC) mounted on them, high-precision radiosurgery applying a LINAC to measure high-dose radiation on the target region has been gaining popularity. Systematic and accurate quality assurance (QA) is of vital important for high-precision radiosurgery because of its increased risk of side effects including life-threatening ones such as overexposure of healthy tissues to high-dose radiation beams concentrated on small areas. Therefore, accurate dose and dose-distribution measurements are crucial in the treatment procedure. The accurate measurement of the properties of beams concentrated on small areas requires high-precision dosimeters capable of high-resolution output and dose mapping as well as accurate dosimetry in penumbra regions. In general, the properties of beams concentrated on small areas are measured using thermos luminescent dosimeters (TLD), diode detectors, ion chambers, diamond detectors, or films, and many papers have presented the advantages and disadvantages of each of these detectors for dosimetry. In this study, a solid-state photoconductor dosimeter was developed, and its clinical usability was tested by comparing its relative dosimetric performance with that of a conventional ion chamber. As materials best-suited for radiation dosimeters, four candidates namely lead (II) iodide (PbI2), lead (II) oxide (PbO), mercury (II) iodide (HgI2), and HgI2/ titanium dioxide (TiO2) composite, the performances of which were proved in previous studies, were used. The electrical properties of each candidate material were examined using the sedimentation method, one of the particle-in-binder (PIB) methods, and unit-cell-type prototypes were fabricated. The unit-cell samples thus prepared were cut into specimens of area 1 × 1 cm2 with 400-μ m thickness. The electrical properties of each sample, such as sensitivity, dark current, output current, rising time

  9. Study on the effect of deposition rate and concentration of Eu on the fluorescent lifetime of CsI: Tl thin film

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Yijun; Guo, Lina [University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, Chengdu 610054 (China); Liu, Shuang, E-mail: shuangliu@uestc.edu.cn [University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, Chengdu 610054 (China); Wang, Qianfeng; Zhang, Shangjian; Liu, Yong [University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, Chengdu 610054 (China); Zhong, Zhiyong [University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, Chengdu 610054 (China)

    2017-06-21

    Although there are many new scintillators being developed recently, CsI: Tl is still very efficient among them. The fluorescent lifetime is a very important parameter of CsI: Tl thin film and two series of experiments have been conducted to learn about it. Our experiments, however, have demonstrated that the deposition rate and the codoping of Eu{sup 2+} will significantly influence its fluorescent lifetime. In order to increase the efficiency of the imaging system, we intend to obtain a higher fluorescent lifetime for CsI: Tl thin film by controlling these two conditions. - Highlights: • We used vacuum vapor deposition method to grow the high-quality thin films. • The relationship between the deposition rate and the fluorescent lifetime of CsI: Tl thin film was tested. • Concentration of Eu on fluorescent lifetime of the CsI: Tl thin film was studied.

  10. ESR and TL age determination of caliche nodules

    Energy Technology Data Exchange (ETDEWEB)

    Oezer, A.M. (Middle East Technical Univ., Ankara (Turkey)); Wieser, A.; Goeksu, H.Y.; Mueller, P.; Regulla, D.F. (Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen, Neuherberg (Germany, F.R.). Inst. fuer Strahlenschutz); Erol, O. (Istanbul Univ. (Turkey). School of Geography and Marine Sciences)

    1989-01-01

    Feasibility of dating caliche nodules by ESR and TL is investigated. For both methods the properties of the dating signal are described. Chemical composition as well as TL glow curves of caliches originating from different localities exhibit some differences. Due to the complexity of the TL glow curves, some samples required a special post-annealing procedure in order to resolve the main TL peak for age determination. Typical ESR calcite signals do not exist in caliche, therefore usefulness of the g=2.0040 ESR signal is studied. The results of TL and ESR ages are found to be compatible except for two samples. Possible causes of the discrepancy in these samples are discussed. It is shown that, with proper treatment of the radiation-induced signals, it was possible to date caliche formations older than 350 ka, which is not achievable with other methods like uranium series disequilibrium and/or radiocarbon dating. (author).

  11. ESR and TL age determination of caliche nodules

    International Nuclear Information System (INIS)

    Oezer, A.M.; Wieser, A.; Goeksu, H.Y.; Mueller, P.; Regulla, D.F.; Erol, O.

    1989-01-01

    Feasibility of dating caliche nodules by ESR and TL is investigated. For both methods the properties of the dating signal are described. Chemical composition as well as TL glow curves of caliches originating from different localities exhibit some differences. Due to the complexity of the TL glow curves, some samples required a special post-annealing procedure in order to resolve the main TL peak for age determination. Typical ESR calcite signals do not exist in caliche, therefore usefulness of the g=2.0040 ESR signal is studied. The results of TL and ESR ages are found to be compatible except for two samples. Possible causes of the discrepancy in these samples are discussed. It is shown that, with proper treatment of the radiation-induced signals, it was possible to date caliche formations older than 350 ka, which is not achievable with other methods like uranium series disequilibrium and/or radiocarbon dating. (author)

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  13. 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)

  14. Angular dependence of the nanoDot OSL dosimeter

    OpenAIRE

    Kerns, James R.; Kry, Stephen F.; Sahoo, Narayan; Followill, David S.; Ibbott, Geoffrey S.

    2011-01-01

    Purpose: Optically stimulated luminescent detectors (OSLDs) are quickly gaining popularity as passive dosimeters, with applications in medicine for linac output calibration verification, brachytherapy source verification, treatment plan quality assurance, and clinical dose measurements. With such wide applications, these dosimeters must be characterized for numerous factors affecting their response. The most abundant commercial OSLD is the InLight∕OSL system from Landauer, Inc. The purpose of...

  15. The NRPB's new dosimeter and dose record keeping services

    International Nuclear Information System (INIS)

    Dennis, J.A.; Marshall, T.O.; Shaw, K.B.

    1976-01-01

    A new automated dosimeter and record keeping service which the National Radiological Protection Board (UK) intends to introduce in 1977 is described. The automated system, based on a thermoluminescent dosimeter, will be linked to a fully computerised record keeping system with automatic printing of dose records and Transfer Records operated at its Headquarters at Harwell. The new system will dispense with much manual labour which in the past has introduced inevitable errors and incurred increasing costs. (U.K.)

  16. The automated Risoe TL dating reader system

    International Nuclear Information System (INIS)

    Boetter-Jensen, L.

    1988-01-01

    The features of the new modified Riso TL dating reader system are described. A vacuum chamber that accommodates the entire 24-position sample changer unit has been designed. The vacuum and N 2 -gas functions are software-controlled. A newly designed heater system is capable of repeated heating cycles to 700 0 C. The sample changer system accommodates fine-grain discs as well as planchettes for coarse grains. Two software-controlled beta irradiators can be attached to the reader, e.g. for predose measurement. The software allows a user without programming expertise to create any desired measuring sequence, and to store and recall data and glow curves for making analyses. (author)

  17. Evaluasi Pengendalian Sistem Informasi Pengiriman pada TL

    Directory of Open Access Journals (Sweden)

    Nelly Nelly

    2011-06-01

    Full Text Available The purpose of this study is to evaluate the control systems on the TL shipping information, in order to discern weaknesses or problems in delivery of enterprise information systems control using CobIT approach. The research method used is the data collecting by observation, checklists, interviews, and literature study. The results achieved are findings and issue recommendations that provide an illustration about a control of the running information delivery systems. From the illustration it is known that on the company’s control of information delivery system, there are still many things that have not been up to standard. The conclusion obtained is that the control of information delivery systems that have been implemented meets only partially the standards set small, so it still needs much improvement. 

  18. Core excitations across the neutron shell gap in 207Tl

    Directory of Open Access Journals (Sweden)

    E. Wilson

    2015-07-01

    Full Text Available The single closed-neutron-shell, one proton–hole nucleus 207Tl was populated in deep-inelastic collisions of a 208Pb beam with a 208Pb target. The yrast and near-yrast level scheme has been established up to high excitation energy, comprising an octupole phonon state and a large number of core excited states. Based on shell-model calculations, all observed single core excitations were established to arise from the breaking of the N=126 neutron core. While the shell-model calculations correctly predict the ordering of these states, their energies are compressed at high spins. It is concluded that this compression is an intrinsic feature of shell-model calculations using two-body matrix elements developed for the description of two-body states, and that multiple core excitations need to be considered in order to accurately calculate the energy spacings of the predominantly three-quasiparticle states.

  19. Quality control 201TlCl solution obtained at IPEN-CNEN/SP through the direct method of 201Tl preparation

    International Nuclear Information System (INIS)

    Fernandes, L.; Silva, C.P.G. da.

    1991-09-01

    The radiopharmaceutical 201 TlCl is used in Nuclear medicine for myocardial visualization. The solution of 201 TlCl was prepared using 201 Tl obtained by irradiating a natural mercury target with protons. This radionuclide was subjected to different quality control processes to verify the purity required for its use in Medicine. Some of these controls concerned the determination of 200 Tl, 201 Tl and 202 Tl; the chemical identification of 201 Tl +1 ; the hydrazine concentration, mercury contamination and the presence of phosphate. Furthermore, the biologic distribution in Wistar rats and tests for sterility, pyrogens and for toxicity were carried out. It was verified that the solution obtained was in the form of thallous chloride. This radiopharmaceutical can give a good heart image in animals but due to the contamination of 201 Tl with 200 Tl and 202 Tl its use in human beings is not possible unless enriched 202 Hg is used as target of irradiation. (author)

  20. Silicon drift detectors coupled to CsI(Tl) scintillators for spaceborne gamma-ray detectors

    International Nuclear Information System (INIS)

    Marisaldi, M.; Fiorini, C.; Labanti, C.; Longoni, A.; Perotti, F.; Rossi, E.; Soltau, H.

    2006-01-01

    Silicon Drift Detectors (SDDs), thanks to their peculiar low noise characteristics, have proven to be excellent photodetectors for CsI(Tl) scintillation light detection. Two basic detector configurations have been developed: either a single SDD or a monolithic array of SDDs coupled to a single CsI(Tl) crystal. A 16 independent detectors prototype is under construction, designed to work in conjunction with the MEGA Compton telescope prototype under development at MPE, Garching, Germany. A single SDD coupled to a CsI(Tl) crystal has also been tested as a monolithic detector with an extended energy range between 1.5 keV and 1 MeV. The SDD is used as a direct X-ray detector for low energy photons interacting in silicon and as a scintillation light photodetector for photons interacting in the crystal. The type of interaction is identified by means of pulse shape discrimination technique. Detectors based on an array of SDDs coupled to a single CsI(Tl) crystal have also been built. The readout of these detectors is based on the Anger camera technique, and submillimeter spatial resolution can be achieved. The two detectors' approaches and their applications will be described