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

International Nuclear Information System (INIS)

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

2014-01-01

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

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

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

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)

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

International Nuclear Information System (INIS)

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

1987-03-01

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

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

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.).

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.

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.)

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.

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

International Nuclear Information System (INIS)

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

2008-01-01

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

Methods for implementation of in vivo dosimetry (entrance dose) using thermoluminescent dosimeters during radiotherapy treatment with photon beam

International Nuclear Information System (INIS)

Barsanelli, Cristiane

2006-01-01

Selection, calibration procedure to convert TLD signal into absorbed dose and physical characteristics at the thermoluminescent dosimeters, as well as the determination of correction factors and the methodology to determine expected entrance dose, are described in this work. Practical aspects and the utility of entrance dose measures with thermoluminescent dosimeters were investigated, as well as the exactness and the reproducibility of the daily dose release. The entrance dose measures were performed in five patients with diagnosis of breast cancer treated with a 6 MV photon beam. The measured dose and the expected dose values agreed in ± 5%, due to excellent treatment equipment stability, to automatic verification system and the good exactness in the daily treatment adjustment. Good precision can be achieved when the correction factors for each parameter of influence in the dosimeter response are carefully determined and applied to convert the thermoluminescent signal into absorbed dose. The study demonstrates the viability of thermoluminescent dosimeters use for in vivo dosimetry and its utility as part of a quality assurance program in a radiation therapy service. (author)

The application of thermoluminescence dosimeter on the measurement of hard X-ray pulse energy spectrum

International Nuclear Information System (INIS)

Song Zhaohui; Wang Baohui; Wang Kuilu; Hei Dongwei; Sun Fengrong; Li Gang

2001-01-01

This paper introduce the application of thermoluminescence dosimeter (TLD) which composed by TLD-3500 Reader and TLD-100M chips on the measurement of hard X-ray pulse energy spectrum. The idea, using Filter Fluorescence Method (FFM) and TLD to measure hard X-ray pulse energy spectrum (from 10 keV to 100 keV), is discussed in details. Considering all the factors of the measuring surroundings, the measurement system of hard X-ray pulse has been devised. The calibration technique of absolute energy response of TLD is established. This method has been applied successfully on the radiation parameters measurement of the huge pulse radiation device -high-power pulser I. Hard X-ray pulse energy spectrum data of the pulser are acquired

Application of thermoluminescence dosimeter on the measurement of hard X-ray pulse energy spectrum

International Nuclear Information System (INIS)

Song Zhaohui; Wang Baohui; Wang Kuilu; Hei Dongwei; Sun Fengrong; Li Gang

2003-01-01

This paper introduces the application of thermoluminescence dosimeter (TLD) which composed by TLD-3500 reader and GR-100 M chips on the measurement of hard X-ray pulse energy spectrum. The idea using Filter Fluorescence Method (FFM) and TLD to measure hard X-ray pulse energy spectrum (from 10 keV to 100 keV) is discussed in details. Considering all the factors of the measuring surrounding, the measurement system of hard X-ray pulse has been devised. The calibration technique of absolute energy response of TLD is established. This method has been applied successfully on the radiation parameters measurement of the huge pulse radiation device-high-power pulser I. Hard X-ray pulse energy spectrum data of the pulser are acquired

Assessment of CaSO4:Dy and LiF:Mg,Ti thermoluminescent dosimeters performance in the dosimetry of clinical electron beams

International Nuclear Information System (INIS)

Nunes, Maira Goes

2008-01-01

The assessment of the performance of CaS0 4 :Dy thermoluminescent detectors produced by IPEN in the dosimetry of clinical electron beams aims to propose an alternative to the LiF:Mg,Ti commercial dosimeters (TLD-100) largely applied in radiation therapy. The two types of thermoluminescent dosimeters were characterised with the use of PMMA, RMI-457 type solid water and water phantoms in radiation fields of 4, 6, 9, 12 and 16 MeV electrons of nominal energies in which the dose-response curves were obtained and the surface and depth doses were determined. The thermoluminescent response dependency with the electron nominal energies and the applied phantom were studied. The CaS0 4 :Dy presented the same behaviour than the LiF:Mg,Ti in such a way that its application as an alternative to the TLD-100 pellets in the radiation therapy dosimetry of electron beams is viable and presents the significantly higher sensitivity to the electron radiation as its main advantage. (author)

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)

The measurement of dose at 70 micrometres' depth using thermoluminescent dosimeters (tlds)

International Nuclear Information System (INIS)

Jones, A.R.

1989-01-01

The measurement of dose with thermoluminescent dosimeters (TLD) at a tissue-equivalent depth of 70 μm can be done in three ways. These are by using: very thin TLDs (made by cementing fine, powdered, TLD particles to a high-temperature plastic film); opaque TLDs whose surface alone is sensitive. (Light emitted at a greater depth has a low probability of emergence and, thus, they behave as if they were thin.); at least three TLDs covered with absorbers of differing thickness. The approaches were studied using examples of dosimeter arrangements of the three types. The characteristics which were measured to form a basis of comparison were: the performance at high and low doses; the effect of changing angle of incidence and beta-ray energy; the effect on performance of repeated irradiation, annealing and reading. It was concluded that the very thin TLDs (powdered) are the best suited to the measurement of doses at 70 μm depth

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

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....

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

Science.gov (United States)

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

2014-01-01

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

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

Science.gov (United States)

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

2010-07-01

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

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

International Nuclear Information System (INIS)

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

1994-01-01

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

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

International Nuclear Information System (INIS)

1982-04-01

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

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

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.

NRC TLD Direct Radiation Monitoring Network

International Nuclear Information System (INIS)

Struckmeyer, R.; McNamara, N.

1991-12-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2011-10-15

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

Calibration of Mg2SiO4(Tb) thermoluminescent dosimeters for use in determining diagnostic X-ray doses to Adult Health Study participants

International Nuclear Information System (INIS)

Kato, Kazuo; Antoku, Shigetoshi; Sawada, Shozo; Russell, W.J.

1989-11-01

Characteristics of Mg 2 SiO 4 (Tb) thermoluminescent dosimeters (TLD) were ascertained preparatory to measuring dose from diagnostic X-ray examinations received by Adult Health Study participants. These detectors are small, relatively sensitive to low-dose X rays, and are appropriate for precise dosimetry. Extensive calibration is necessary for precisely determining doses according to their thermoluminescent intensities. Their sensitivities were investigated, by dose according to X-ray tube voltage, and by exposure direction, to obtain directional dependence. Dosimeter sensitivity lessened due to the fading effect and diminution of the planchet. However, these adverse effects can be avoided by storing the dosimeters at least 1.5 hours and by using fresh silver-plated planchets. Thus, the TLDs, for which sensitivities were determined in this study, will be useful in subsequent diagnostic X-ray dosimetry. (author)

Personnel radiation monitoring by thermoluminescence dosimetry (1995-96)

International Nuclear Information System (INIS)

Daw Mi Cho Cho; Daw Yi Yi Khin; Daw San San; U Maung Maung Tin; Daw Hla Hla Win

2001-01-01

Personnel radiation monitoring which is the dose assessment of individual doses from external radiation received by radiation workers has been carried out by Thermoluminescence Dosimetry system consisting of a Vinten Toledo TLD reader, LiF dosimeters and associated equipment. The exposed TLD dosimeters were measured by TLD reader and the dose evaluation and dose registration were done on personal computer. Due to the records of 1995-96, most of the radiation workers complied with the permissible dose recommended by IAEA and ICRP 60. (author)

Evaluation of thermoluminescent dosimeters (TLDs) of two different designs for beta particle and low energy photon dosimetry

International Nuclear Information System (INIS)

Nugent, K.J.; Ahmed, A.B.; Groer, P.G.

1992-11-01

The purpose of this research was to compare the response of the thermoluminescent dosimeters (TLDs) currently used at Martin Marietta Energy Systems with that of a newly designed TLD which is now under consideration. The new TLD consists of a thicker chip in element No. 3 and a thinner, more opaque mylar filter over this same element. The goals were to determine if the new (proposed) TLD would perform significantly different from the old (current) TLD when measuring dose equivalents from beta particles and low energy photons (x-rays) and to find out if changing from the old to the new design would require that modifications be made to the calibration factors currently used in the dose calculation algorithm. To accomplish these objectives, tests were performed using both types of dosimeters placed under identical conditions. Their responses were then compared and analyzed. It was concluded that the new TLDs would allow for the detection of lower levels of radiation and give more precise readouts at very low (i.e., background) levels in addition to the obvious advantages of the new design, such as, a thicker, more durable chip and a more opaque mylar. It was also determined that no adjustments to the calibration factors would be necessary in switching to the new design

Background radiation accumulation and lower limit of detection in thermoluminescent beta-gamma dosimeters used by the centralized external dosimetry system

International Nuclear Information System (INIS)

Sonder, E.; Ahmed, A.B.

1991-12-01

A value for ''average background radiation'' of 0.75 mR/week has been determined from a total of 1680 thermoluminescent dosimeters (TLD's) exposed in 70 houses for periods up to one year. The distribution of results indicates a rather large variation among houses, with a few locations exhibiting backgrounds double the general average. Some discrepancies in the short-term background accumulation of TLD's have been explained as being due to light leakage through the dosimeter cases. In addition the lower limit of detection (L D ) for deep and shallow dose equivalents has been determined for these dosimeters. The L D for occupational exposure depends strongly on the time a dosimeter is exposed to background radiation in the field. The L D can vary from a low of 2.4 mrem for high energy gamma rays when the background accumulation period is less than a few weeks to values as high as 66 mrem for uranium beta particles when background has been allowed to accumulate for more than 21 weeks

Evaluation of thermoluminescent dosimeters using water equivalent phantoms for application in clinical electrons beams dosimetry

International Nuclear Information System (INIS)

Bravim, Amanda

2010-01-01

The dosimetry in Radiotherapy provides the calibration of the radiation beam as well as the quality control of the dose in the clinical routine. Its main objective is to determine with greater accuracy the dose absorbed by the tumor. This study aimed to evaluate the behavior of three thermoluminescent dosimeters for the clinical electron beam dosimetry. The performance of the calcium sulfate detector doped with dysprosium (CaSO 4 : Dy) produced by IPEN was compared with two dosimeters commercially available by Harshaw. Both are named TLD-100, however they differ in their dimensions. The dosimeters were evaluated using water, solid water (RMI-457) and PMMA phantoms in different exposure fields for 4, 6, 9, 12 and 16 MeV electron beam energies. It was also performed measurements in photon beams of 6 and 15 MV (2 and 5 MeV) only for comparison. The dose-response curves were obtained for the 60 Co gamma radiation in air and under conditions of electronic equilibrium, both for clinical beam of photons and electrons in maximum dose depths. The sensitivity, reproducibility, intrinsic efficiency and energy dependence response of dosimeters were studied. The CaSO 4 : Dy showed the same behavior of TLD-100, demonstrating only an advantage in the sensitivity to the beams and radiation doses studied. Thus, the dosimeter produced by IPEN can be considered a new alternative for dosimetry in Radiotherapy departments. (author)

Clinical use of carbon-loaded thermoluminescent dosimeters for skin dose determination

International Nuclear Information System (INIS)

Ostwald, Patricia M.; Kron, Tomas; Hamilton, Christopher S.; Denham, James W.

1995-01-01

Purpose: Carbon-loaded thermoluminescent dosimeters (TLDs) are designed for surface/skin dose measurements. Following 4 years in clinical use at the Mater Hospital, the accuracy and clinical usefulness of the carbon-loaded TLDs was assessed. Methods and Materials: Teflon-based carbon-loaded lithium fluoride (LiF) disks with a diameter of 13 mm were used in the present study. The TLDs were compared with ion chamber readings and TLD extrapolation to determine the effective depth of the TLD measurement. In vivo measurements were made on patients receiving open-field treatments to the chest, abdomen, and groin. Skin entry dose or entry and exit dose were assessed in comparison with doses estimated from phantom measurements. Results: The effective depth of measurement in a 6 MV therapeutic x-ray beam was found to be about 0.10 mm using TLD extrapolation as a comparison. Entrance surface dose measurements made on a solid water phantom agreed well with ion chamber and TLD extrapolation measurements, and black TLDs provide a more accurate exit dose than the other methods. Under clinical conditions, the black TLDs have an accuracy of ± 5% (± 2 SD). The dose predicted from black TLD readings correlate with observed skin reactions as assessed with reflectance spectroscopy. Conclusion: In vivo dosimetry with carbon-loaded TLDs proved to be a useful tool in assessing the dose delivered to the basal cell layer in the skin of patients undergoing radiotherapy

Preparation Of Thermoluminescence Dosimeters For External Radiotherapy Beam Audit In Malaysia

International Nuclear Information System (INIS)

Norhayati Abdullah; Siti Sara Deraman; Taiman Kadni; Mohd Taufik Dollah; Norhayati Salleh

2014-01-01

The external beam audit is a part of the Quality Assurance Programme (QAP) in radiotherapy that should be carried out to check the accuracy of dose delivered by the radiotherapy treatment units are within the tolerance limit of A ± 5 % as recommended by the International Commission of Radiation Units and Measurements (ICRU) Report No. 24. In this work, thermoluminescence dosimeters (TLD) in powder form were chosen to be used in the dose quality audit for the radiotherapy treatment units in Malaysia. As a preparation, the characterizations of a new batch of TLD-100 powders were studied. The studies include checks for the response of TLD-100 before and after pre-annealing process, reproducibility and linearity of TL signal. Results show that the response of TLD-100 powder after pre-annealing increases by 65 % compared with before pre-annealing process. These TLD-100 powders also provide reliable and consistent readings for the absorbed dose to water within the range of 150 cGy to 250 cGy with the maximum standard uncertainty of 0.554 μC. Finally, the calibration curves for 6 MV and 10 MV photon beams were established. These curves will be used in determining the absorbed dose to water (Dw) from user's irradiated TLDs. The expanded uncertainty (coverage factor k=2) of Dw determination was estimated to be 4.1 %. As a conclusion, these TLD-100 powders are ready to be used as a transfer detector for evaluating the accuracy of user's delivery dose in the radiotherapy beam audit program in Malaysia. (author)

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

Dosimetric parameters for small field sizes using Fricke xylenol gel, thermoluminescent and film dosimeters, and an ionization chamber

International Nuclear Information System (INIS)

Guzman Calcina, Carmen S; Oliveira, Lucas N de; Almeida, Carlos E de; Almeida, Adelaide de

2007-01-01

Dosimetric measurements in small therapeutic x-ray beam field sizes, such as those used in radiosurgery, that have dimensions comparable to or smaller than the build-up depth, require special care to avoid incorrect interpretation of measurements in regions of high gradients and electronic disequilibrium. These regions occur at the edges of any collimated field, and can extend to the centre of small fields. An inappropriate dosimeter can result in an underestimation, which would lead to an overdose to the patient. We have performed a study of square and circular small field sizes of 6 MV photons using a thermoluminescent dosimeter (TLD), Fricke xylenol gel (FXG) and film dosimeters. PMMA phantoms were employed to measure lateral beam profiles (1 x 1, 3 x 3 and 5 x 5 cm 2 for square fields and 1, 2 and 4 cm diameter circular fields), the percentage depth dose, the tissue maximum ratio and the output factor. An ionization chamber (IC) was used for calibration and comparison. Our results demonstrate that high resolution FXG, TLD and film dosimeters agree with each other, and that an ionization chamber, with low lateral resolution, underestimates the absorbed dose. Our results show that, when planning small field radiotherapy, dosimeters with adequate lateral spatial resolution and tissue equivalence are required to provide an accurate basic beam data set to correctly calculate the absorbed dose in regions of electronic disequilibrium

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).

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

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-06-15

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

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)

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

International Nuclear Information System (INIS)

Struckmeyer, R.; McNamara, N.

1988-09-01

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

measurement of the supralinearity of 7LiF thermoluminescent dosimeters

International Nuclear Information System (INIS)

Hancock, I.B.

1978-04-01

A study has been made of the supralinearity of the 7 LiF thermoluminesecent dosimeter (T.L.D.) used in the UKAEA personnel criticality dosimeter by exposure to a 60 Co source. the response of the T.L.D. was linear up to approximately 450 rad, above which it became increasingly supralinear, over-reading by about 50% at 2000 rad. The results have been used to produce a correction graph, as a function of apparent dose up to 3500 rad, for routine use in nuclear accident dosimetry. (author)

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-05-01

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

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)

Thermoluminescence: how safe are we? ask the crystals

International Nuclear Information System (INIS)

Madiyal, Ananya; Alva, Priyadharshini

2013-01-01

Thermoluminescence means 'light emitted from heat'. Thermoluminescent dosimeter (TLD) is a type of radiation measuring instrument used for the measurement of actual dose received by the operator or patient as a result of radiographic exposure. TLD calculates the ionising radiation exposure by measuring the amount of visible light emitted from a crystal in the detector when the crystal is heated. The two types of TLD are Calcium Fluoride type and the Lithium Fluoride type. The former is used for environmental detection of radiation exposure while the latter is used for detection of personal radiation exposure. A TLD card consists of a nickel plated aluminium plate and 3 filters. The equipment used to heat the exposed material and measure the emitted light produced by heat is called TLD reader. It comprises of a heater, a photomultiplier tube and the electronic system. TLD is used to measure the dose received by a patient while undergoing radiotherapy, for radio-diagnosis and as personnel monitoring devices. It has the advantage of being small in size, chemically inert, accurate and gives a reproducible reading. (author)

Fast neutron dosimetry using CaSO4:Dy thermoluminescent dosimeters

International Nuclear Information System (INIS)

Azorin, N.G.; Salvi, C.R.; Rubio, J.L.; Gutierrez, C.A.

1980-01-01

The use of CaSO 4 :Dy phosphor powder in fast neutron dose measurements using the activation of sulphur from the 32 S(n,p) 32 P reaction is described. The thermoluminescence induced during the irradiation and that due to the decay of short-lived activation products, is erased by annealing the dosimeters after a post-irradiation time of 3 days. The self-induced thermoluminescence measured at different intervals of post-irradiation time, gives an estimation of the fast neutron dose to which the dosimeters were exposed

Thermoluminescent dosemeters characterization for patient dosimetry in diagnostic radiology preliminary results

International Nuclear Information System (INIS)

Castro, William J.; Squair, Peterson L.; Gonzaga, Natalia B.; Nogueira, Maria S.; Silva, Teogenes A. da

2009-01-01

The determination of the metrological characteristics of thermoluminescent (TL) dosimeters plays an important role in dosimetry of patients submitted to x-ray examinations for diagnostic purpose. Entrance surface doses can be measured with TL dosimeters to verify the compliance with the diagnostic reference levels. Organ doses can be estimated through TL measurements in an anthropomorphic phantom which it allows the radiation risk assessment. In this work, LiF:Mg,Ti (TLD-100) rod and chip thermoluminescent dosimeters were characterized considering their use for patient dosimetry in computerized tomography and mammography. Preliminary results showed that TL dosimeters have a response reproducibility of 7.8% and 4.8% and homogeneity of 18.4% and 6.5% for rod and chip shapes, respectively. (author)

Optimized computational method for determining the beta dose distribution using a multiple-element thermoluminescent dosimeter system

International Nuclear Information System (INIS)

Shen, L.; Levine, S.H.; Catchen, G.L.

1987-01-01

This paper describes an optimization method for determining the beta dose distribution in tissue, and it describes the associated testing and verification. The method uses electron transport theory and optimization techniques to analyze the responses of a three-element thermoluminescent dosimeter (TLD) system. Specifically, the method determines the effective beta energy distribution incident on the dosimeter system, and thus the system performs as a beta spectrometer. Electron transport theory provides the mathematical model for performing the optimization calculation. In this calculation, parameters are determined that produce calculated doses for each of the chip/absorber components in the three-element TLD system. The resulting optimized parameters describe an effective incident beta distribution. This method can be used to determine the beta dose specifically at 7 mg X cm-2 or at any depth of interest. The doses at 7 mg X cm-2 in tissue determined by this method are compared to those experimentally determined using an extrapolation chamber. For a great variety of pure beta sources having different incident beta energy distributions, good agreement is found. The results are also compared to those produced by a commonly used empirical algorithm. Although the optimization method produces somewhat better results, the advantage of the optimization method is that its performance is not sensitive to the specific method of calibration

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.)

A TLD dose algorithm using artificial neural networks

International Nuclear Information System (INIS)

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

1995-01-01

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

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).

Thermoluminescent dosimetry for LDEF experiment M0006

International Nuclear Information System (INIS)

Chang, J.Y.; Giangano, D.; Kantorcik, T.; Stauber, M.; Snead, L.

1992-01-01

Experiment M0006 on the Long Duration Exposure Facility had as its objective the investigation of space radiation effects on various electronic and optical components, as well as on seed germination. The Grumman Corporate Research Center provided the radiation dosimetric measurements for M0006, comprising the preparation of thermoluminescent dosimeters (TLD) and the subsequent measurement and analysis of flight exposed and control samples. In addition, various laboratory exposures of TLD's with gamma rays and protons were performed to obtain a better understanding of the flight exposures

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)

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

Hanford environmental CaF2:Mn thermoluminescent dosimeter

Energy Technology Data Exchange (ETDEWEB)

Fix, J.J.; Miller, M.L.

1978-03-01

The TLD-400 chips combined with the Pb-Ta field capsule provide a sensitive method of measuring penetrating ambient radiation in the environment. The method is best used for field deployments of about 1 month or less to minimize problems associated with fading. A correction factor of about 10% is necessary for the readings obtained for a 28-day field deployment and a 1-day wait before readout. Integration of reader output from 150/sup 0/C to 280/sup 0/C provides a good signal-to-noise ratio for TLD-400 chips exposed to 5 mR for the reader and planchet described herein. Visual inspection of the glow curves is recommended during startup of any new program or following any major instrument repair. The glow curves can be easily drawn with an X-Y recorder. Because of the large energy dependence of bare TLD-400 chips, an energy-flattening filter is necessary to allow a direct conversion from a reference exposure to observed field exposures. The field capsule used, consisting of 10 mil of tantalum and 2 mil of lead, provides an approximate uniform energy response above 70 keV. Below 70 keV, the response decreases rapidly because of the shielding. Experiments conducted have not shown the TLD-400 chips to be sensitive to the extremes of summer temperature (approximately 50/sup 0/C) occasionally encountered at Hanford. Although the field dosimeter exhibits a directional dependence, this is of primary concern during calibration, in which the axis of the dosimeter should be normal to the photon beam. The procedures used to interpret the TLD chip reader output in terms of dose are fully described in the text.

Site-specific calibration of the Hanford personnel neutron dosimeter

International Nuclear Information System (INIS)

Endres, A.W.; Brackenbush, L.W.; Baumgartner, W.V.; Rathbone, B.A.

1994-10-01

A new personnel dosimetry system, employing a standard Hanford thermoluminescent dosimeter (TLD) and a combination dosimeter with both CR-39 nuclear track and TLD-albedo elements, is being implemented at Hanford. Measurements were made in workplace environments in order to verify the accuracy of the system and establish site-specific factors to account for the differences in dosimeter response between the workplace and calibration laboratory. Neutron measurements were performed using sources at Hanford's Plutonium Finishing Plant under high-scatter conditions to calibrate the new neutron dosimeter design to site-specific neutron spectra. The dosimeter was also calibrated using bare and moderated 252 Cf sources under low-scatter conditions available in the Hanford Calibration Laboratory. Dose equivalent rates in the workplace were calculated from spectrometer measurements using tissue equivalent proportional counter (TEPC) and multisphere spectrometers. The accuracy of the spectrometers was verified by measurements on neutron sources with calibrations directly traceable to the National Institute of Standards and Technology (NIST)

Dosimetric behavior of thermoluminescent dosimeters at low doses in diagnostic radiology

International Nuclear Information System (INIS)

Del Sol F, S.; Garcia S, R.; Guzman M, J.; Sanchez G, D.; Rivera M, T.; Ramirez R, G.; Gaona, E.

2015-10-01

Thermoluminescent (Tl) characteristics of TLD-100, LiF:Mg,Cu,P, and CaSO 4 : Dy the under homogeneous field of X-ray beams of diagnostic irradiation and its verification using thermoluminescent dosimetry is presented. The irradiations were performed utilizing an X-ray beam generated by a Radiology Mexican Company: MRH-II E GMX 325-AF SBV-1 model, with Rotating Anode X-Ray Tube installed in the Hospital Juarez Norte de Mexico in Mexico City. Different thermoluminescent characteristics of dosimetric material were studied, such as, batch homogeneity, Tl glow curve, Tl response as a function of X-ray dose, reproducibility and fading. Materials were calibrated in terms of absorbed dose to the standard calibration distance and positioned in a generic Phantom was used. Dose verification and comparison with the measurements made with that obtained by TLD-100 were analyzed. Preliminary results indicate the dosimetric peak appears at 243, 236 and 277 ± 5 degrees C respectively, these peaks are in agreement with that reported in the literature. Tl glow curve as a function of X-ray dose showed a linearity in the range from 1.76 mGy up to 14.70 mGy for all materials. Fading for a period of one month at room temperature showed low fading LiF:Mg,Cu,P, medium and high for TLD-100 and CaSO 4 : Dy. The results suggest that the three materials are suitable for measurements at low doses in radiodiagnostic, however, for its dosimetric characteristics are most effective for individual applications: personal dosimetry and monitors limb (LiF:Mg,Cu,P), clinical dosimetry and environmental (TLD-100 and CaSO 4 : Dy). (Author)

Thermoluminescent dosimetry and assessment of personal dose

International Nuclear Information System (INIS)

Boas, J.F.; Martin, L.J.; Young, J.G.

1982-01-01

Thermoluminescence is discussed in terms of the energy band structure of a crystalline solid and the trapping of charge carriers by point defects. Some general properties of thermoluminescent materials used for dosimetry are outlined, with thermoluminescence of CaSO 4 :Dy being described in detail. The energy response function and the modification of the energy response of a dosimeter by shielding are discussed. The final section covers the connection between exposure, as recorded by a TLD badge, and the absorbed dose to various organs from gamma radiation in a uranium mine; the conversion from absorbed dose to dose equivalent; and uncertainties in assessment of dose equivalent

Assessment of CaSO{sub 4}:Dy and LiF:Mg,Ti thermoluminescent dosimeters performance in the dosimetry of clinical electron beams; Avaliacao do desempenho dos detectores termoluminesncetes de CaSO{sub 4}:Dy e LiF:Mg,Ti na dosimetria de feixes clinicos de eletrons

Energy Technology Data Exchange (ETDEWEB)

Nunes, Maira Goes

2008-07-01

The assessment of the performance of CaS0{sub 4}:Dy thermoluminescent detectors produced by IPEN in the dosimetry of clinical electron beams aims to propose an alternative to the LiF:Mg,Ti commercial dosimeters (TLD-100) largely applied in radiation therapy. The two types of thermoluminescent dosimeters were characterised with the use of PMMA, RMI-457 type solid water and water phantoms in radiation fields of 4, 6, 9, 12 and 16 MeV electrons of nominal energies in which the dose-response curves were obtained and the surface and depth doses were determined. The thermoluminescent response dependency with the electron nominal energies and the applied phantom were studied. The CaS0{sub 4}:Dy presented the same behaviour than the LiF:Mg,Ti in such a way that its application as an alternative to the TLD-100 pellets in the radiation therapy dosimetry of electron beams is viable and presents the significantly higher sensitivity to the electron radiation as its main advantage. (author)

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

International Nuclear Information System (INIS)

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

2012-01-01

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

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

Directory of Open Access Journals (Sweden)

Raffaele Liuzzi

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

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...

BaSO4:Eu as an energy independent thermoluminescent radiation dosimeter for gamma rays and C6+ ion beam

Science.gov (United States)

Sharma, Kanika; Bahl, Shaila; Singh, Birendra; Kumar, Pratik; Lochab, S. P.; Pandey, Anant

2018-04-01

BaSO4:Eu nanophosphor is delicately optimized by varying the concentration of the impurity element and compared to the commercially available thermoluminescent dosimeter (TLD) LiF:Mg,Ti (TLD-100) and by extension also to CaSO4:Dy (TLD-900) so as to achieve its maximum thermoluminescence (TL) sensitivity. Further, the energy dependence property of this barite nanophosphor is also explored at length by exposing the phosphor with 1.25 MeV of Co-60, 0.662 MeV of Cs-137, 85 MeV and 65 MeV of Carbon ion beams. Various batches of the phosphor at hand (with impurity concentrations being 0.05, 0.10, 0.20, 0.50 and 1.00 mol%) are prepared by the chemical co-precipitation method out of which BaSO4:Eu with 0.20 mol% Eu exhibits the maximum TL sensitivity. Further, the optimized nanophosphor exhibits a whopping 28.52 times higher TL sensitivity than the commercially available TLD-100 and 1.426 times higher sensitivity than TLD-900, a noteworthy linear response curve for an exceptionally wide range of doses i.e. 10 Gy to 2 kGy and a simple glow curve structure. Furthermore, when the newly optimized nanophosphor is exposed with two different energies of gamma radiations, namely 1.25 MeV of Co-60 (dose range- 10-300 Gy) and 0.662 MeV of Cs-137 (dose range- 1-300 Gy), it is observed that the shape and structure of the glow curves remain remarkably similar for different energies of radiation while the TL response curve shows little to no variation. When exposed to different energies of carbon ion beam BaSO4:Eu displays energy independence at lower doses i.e. from 6.059 to 14.497 kGy. Finally, even though energy independence is lost at higher doses, the material shows high sensitivity to higher energy (85 MeV) of carbon beam compared to the lower energy (65 MeV of C6+) and saturation is apparent only after 121.199 kGy. Therefore the present nanophosphor displays potential as an energy independent TLD.

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

International Nuclear Information System (INIS)

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

2009-01-01

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

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

Science.gov (United States)

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

2009-09-01

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

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.)

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.)

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

Evaluating the consistency of location of the most severe acute skin reaction and highest skin dose measured by thermoluminescent dosimeter during radiotherapy for breast cancer

Energy Technology Data Exchange (ETDEWEB)

Sun, Li-Min, E-mail: limin.sun@yahoo.com [Department of Radiation Oncology, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung City, Taiwan (China); Huang, Chih-Jen [Department of Radiation Oncology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Department of Faculty of Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Department of College of Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Chen, Hsiao-Yun [Department of Radiation Oncology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Chang, Gia-Hsin [Department of Radiation Oncology, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung City, Taiwan (China); Tsao, Min-Jen [Department of General Surgery, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung City, Taiwan (China)

2016-10-01

We conducted this prospective study to evaluate whether the location of the most severe acute skin reaction matches the highest skin dose measured by thermoluminescent dosimeter (TLD) during adjuvant radiotherapy (RT) for patients with breast cancer after breast conservative surgery. To determine whether TLD measurement can reflect the location of the most severe acute skin reaction, 80 consecutive patients were enrolled in this prospective study. We divided the irradiated field into breast, axillary, inframammary fold, and areola/nipple areas. In 1 treatment session when obvious skin reaction occurred, we placed the TLD chips onto the 4 areas and measured the skin dose. We determined whether the highest measured skin dose area is consistent with the location of the most severe skin reaction. The McNemar test revealed that the clinical skin reaction and TLD measurement are more consistent when the most severe skin reaction occurred at the axillary area, and the p = 0.0108. On the contrary, TLD measurement of skin dose is less likely consistent with clinical observation when the most severe skin reaction occurred at the inframammary fold, breast, and areola/nipple areas (all the p > 0.05). Considering the common site of severe skin reaction over the axillary area, TLD measurement may be an appropriate way to predict skin reaction during RT.

In vivo dosimetry with thermoluminescent dosimeters in radiotherapy: entrance and exit doses

International Nuclear Information System (INIS)

Alves, C.; Lopes, M.C.

2000-01-01

In vivo dosimetry, by entrance and exit dose measurements, is a vital part of a radiotherapy quality assurance program. The uncertainty associated with dose delivery is internationally accepted to be within 5% or inferior depending on the tumor pathology. Thermoluminescent dosimetry is one of the dosimetric techniques used to verify the agreement between delivered and prescribed doses. Nevertheless, it requires a very accurate calibration methodology. We have used LiF chips (4.5 mm diameter and 0.8 mm thick) calibrated towards a PTW ionization chamber of 0.3 cc, in three photon energies: Co-60, 4 and 6 MeV. The TLD reader used was a Rialto 688 from NE Technology and the annealing oven the Eurotherm type 815. The calibration methodology relies on the experimental determination of individual correction factors and on a correction factor derived from a control group of dosimeters. The exit and entrance dose measurements are performed in quite different situations. To be able to achieve those two quantities with TLD, these should be independently calibrated according to the measurement conditions. Alternatively, we can use a single calibration, in entrance dose, and convert the result to the exit dose value by introducing some correction factors. These corrections are related to the different measurement depths and to the different backscattering contributions. We have proved that within an acceptable error we can perform a single calibration and adopt the correction factors which are energy and field size dependent. (author)

Comparison of characteristics of LiF:Mg,Ti e LiF:Mg,Cu,P thermoluminescent dosemeters; Comparacao das caracteristicas dos dosimetros termoluminescentes LiF:Mg,Ti e LiF:Mg,Cu,P

Energy Technology Data Exchange (ETDEWEB)

Pereira, M.S.; Filipov, D., E-mail: dfilipov@utfpr.edu.br [Universidade Tecnologica Federal do Parana (UTFPR/DAFIS), Curitiba, PR (Brazil). Departamento Academicao de Fisica; Schelin, H.R. [Instituto de Pesquisa Pele Pequeno Principe (IPPPP), Curitiba, PR (Brazil)

2014-07-01

The aim of the current study was to compare the thermoluminescent dosimeters LiF:Mg,Ti (TLD-100) and LiF:Mg,Cu,P (MCP) data, which were acquired by the Federal Technological University - Parana. Tests were realized, for this purpose, such as: sensitivity (only one MCP TLD did not present results within the limit range), linearity (whose MCP result was better than the TLD-100 one), energy dependence (TLD-100 presented lower variation than MCP TLD) and reproducibility (whose TLD-100 results were better than the MCP ones). The results from both dosimeters show that these TLDs attend radiodiagnostic dosimetry criteria, however MCP had more satisfactory results. (author)

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)

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.

Thermoluminescence and phosphate glass dosimeter systems in the low dose range

International Nuclear Information System (INIS)

Piesch, E.; Burgkhardt, B.

1978-06-01

This report describes a standard test program for TLD and RPL systems worked out by the Working Party on 'Dose Measurement of External Radiation' by the Fachverband fuer Strahlenschutz e.V. to demonstrate the performance of dosimeter systems to be employed in environmental monitoring and in personnel dosimetry. The results of an intercomparison study are outlined in which 17 laboratories from the German speaking countries participated with 43 dosimeter systems. (orig.) [de

TLD DRD dose discrepancy: role of beta radiation fields

International Nuclear Information System (INIS)

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

2014-01-01

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

Environmental monitoring with TLD in Costa Rica

International Nuclear Information System (INIS)

Mora, P.; Mora, E.

2003-01-01

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

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)

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

International Nuclear Information System (INIS)

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

2011-10-01

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

Thermoluminescent properties of CVD diamond: applications to ionising radiation dosimetry

International Nuclear Information System (INIS)

Petitfils, A.

2007-09-01

Remarkable properties of synthetic diamond (human soft tissue equivalence, chemical stability, non-toxicity) make this material suitable for medical application as thermoluminescent dosimeter (TLD). This work highlights the interest of this material as radiotherapy TLD. In the first stage of this work, we looked after thermoluminescent (TL) and dosimetric properties of polycrystalline diamond made by Chemically Vapor Deposited (CVD) synthesis. Dosimetric characteristics are satisfactory as TLD for medical application. Luminescence thermal quenching on diamond has been investigated. This phenomenon leads to a decrease of dosimetric TL peak sensitivity when the heating rate increases. The second part of this work analyses the use of synthetic diamond as TLD in radiotherapy. Dose profiles, depth dose distributions and the cartography of an electron beam obtained with our samples are in very good agreement with results from an ionisation chamber. It is clearly shown that CVD) diamond is of interest to check beams of treatment accelerators. The use of these samples in a control of treatment with Intensity Modulated Radiation Therapy underlines good response of synthetic diamond in high dose gradient areas. These results indicate that CVD diamond is a promising material for radiotherapy dosimetry. (author)

In vivo thermoluminescent dosimetry on the radiotherapy of limphomas, esophageal and uterine tumour

International Nuclear Information System (INIS)

Morales, F.C.

1982-01-01

A comparative study between dose distribution in pre-selected tumoral plans was established through measurements with thermoluminescent dosimeters and calculations based on 'scatter-air-ratios' properties, isodose curves and collected data. Clinic dosimetry was performed 'in vivo' with LiF dosimeters (TLD-100) and LiF Teflon (1 mm theta, 6 mm lenght). Patients with Hodgkin's disease, carcinoma of the esophagus and of the uterine cervix were selected. Telecobaltherapy was used for these groups of neoplasic conditions. (M.A.C.) [pt

An experimental system for thermoluminescent dosimetry

International Nuclear Information System (INIS)

Perry, K.E.G.; George, E.

1965-08-01

A thermoluminescent dosimeter (T.L.D.) reader has been developed for experimental investigations on the use of lithium fluoride for 'finger tip' dosimetry. The design of the reader is based on the maximum use of standard electronic units in the A.E.R.E. Type 2000 series but some new unit development has been necessary. The reader gives improved experimental facilities over present commercially-available designs. The technique for 'finger-tip' dosimetry is described and the initial experimental results are given. (author)

Dosimetric Characteristics of Radio-Photoluminescent Glass Dosimeters for Medical Applications: Linearity

Energy Technology Data Exchange (ETDEWEB)

Shehzadi, N. N.; Jeong, J. P.; Kim, B. C.; Kim, I. J.; Yi, C. Y. [Center for Ionizing Radiation, Korea Research Institute of Standards and Science, Seoul (Korea, Republic of)

2017-04-15

Radio-photoluminescent glass dosimeter (GD) has advantage of non-destructive reading process, negligible fading and superior radiation detection characteristics than other personal dosimeters like thermoluminescent dosimeters (TLD) or film dosimeters. In this study, one dosimetric characteristic of GDs, dose linearity was evaluated with two different approaches: one for each set of GDs selected and another for a batch of them using accumulated doses of same set of GDs and GDs in a batch, respectively. Within a dose range upto 10 Gy, not only each set of GDs but also a batch of them showed excellent linearity. Within a dose range upto 10 Gy, not only each set of GDs but also a batch of them showed excellent linearity.

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

International Nuclear Information System (INIS)

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

1992-09-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2008-02-15

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

An optical fibre-type silicate glass thermoluminescent detector

International Nuclear Information System (INIS)

Zheng Zheng; Dai Honggui; Hu Shangze; Liu Jian; Fang Jie

1991-01-01

A description of dosimetric properties and the preparation method of an optical fibre-type silicate glass thermoluminescent detector (TLD) is presented. Results showed that this new phosphor is a good one which could be used as a routine dosimeter in the range 10 -1 -10 3 Gy. The preparation method is a new one which differs greatly from all previous ones. Furthermore this kind of detector is small and of low weight. (orig.)

Determination of the intrinsic energy dependence of LiF:Mg,Ti thermoluminescent dosimeters for 125I and 103Pd brachytherapy sources relative to 60Co.

Science.gov (United States)

Reed, J L; Rasmussen, B E; Davis, S D; Micka, J A; Culberson, W S; DeWerd, L A

2014-12-01

To determine the intrinsic energy dependence of LiF:Mg,Ti thermoluminescent dosimeters (TLD-100) for (125)I and (103)Pd brachytherapy sources relative to (60)Co. LiF:Mg,Ti TLDs were irradiated with low-energy brachytherapy sources and with a (60)Co teletherapy source. The brachytherapy sources measured were the Best 2301 (125)I seed, the OncoSeed 6711 (125)I seed, and the Best 2335 (103)Pd seed. The TLD light output per measured air-kerma strength was determined for the brachytherapy source irradiations, and the TLD light output per air kerma was determined for the (60)Co irradiations. Monte Carlo (MC) simulations were used to calculate the dose-to-TLD rate per air-kerma strength for the brachytherapy source irradiations and the dose to TLD per air kerma for the (60)Co irradiations. The measured and MC-calculated results for all irradiations were used to determine the TLD intrinsic energy dependence for (125)I and (103)Pd relative to (60)Co. The relative TLD intrinsic energy dependences (relative to (60)Co) and associated uncertainties (k = 1) were determined to be 0.883 ± 1.3%, 0.870 ± 1.4%, and 0.871 ± 1.5% for the Best 2301 seed, OncoSeed 6711 seed, and Best 2335 seed, respectively. The intrinsic energy dependence of TLD-100 is dependent on photon energy, exhibiting changes of 13%-15% for (125)I and (103)Pd sources relative to (60)Co. TLD measurements of absolute dose around (125)I and (103)Pd brachytherapy sources should explicitly account for the relative TLD intrinsic energy dependence in order to improve dosimetric accuracy.

Determination of the intrinsic energy dependence of LiF:Mg,Ti thermoluminescent dosimeters for 125I and 103Pd brachytherapy sources relative to 60Co

International Nuclear Information System (INIS)

Reed, J. L.; Micka, J. A.; Culberson, W. S.; DeWerd, L. A.; Rasmussen, B. E.; Davis, S. D.

2014-01-01

Purpose: To determine the intrinsic energy dependence of LiF:Mg,Ti thermoluminescent dosimeters (TLD-100) for 125 I and 103 Pd brachytherapy sources relative to 60 Co. Methods: LiF:Mg,Ti TLDs were irradiated with low-energy brachytherapy sources and with a 60 Co teletherapy source. The brachytherapy sources measured were the Best 2301 125 I seed, the OncoSeed 6711 125 I seed, and the Best 2335 103 Pd seed. The TLD light output per measured air-kerma strength was determined for the brachytherapy source irradiations, and the TLD light output per air kerma was determined for the 60 Co irradiations. Monte Carlo (MC) simulations were used to calculate the dose-to-TLD rate per air-kerma strength for the brachytherapy source irradiations and the dose to TLD per air kerma for the 60 Co irradiations. The measured and MC-calculated results for all irradiations were used to determine the TLD intrinsic energy dependence for 125 I and 103 Pd relative to 60 Co. Results: The relative TLD intrinsic energy dependences (relative to 60 Co) and associated uncertainties (k = 1) were determined to be 0.883 ± 1.3%, 0.870 ± 1.4%, and 0.871 ± 1.5% for the Best 2301 seed, OncoSeed 6711 seed, and Best 2335 seed, respectively. Conclusions: The intrinsic energy dependence of TLD-100 is dependent on photon energy, exhibiting changes of 13%–15% for 125 I and 103 Pd sources relative to 60 Co. TLD measurements of absolute dose around 125 I and 103 Pd brachytherapy sources should explicitly account for the relative TLD intrinsic energy dependence in order to improve dosimetric accuracy

Electron-energy deposition in skin and thermoluminescence dosimeters

International Nuclear Information System (INIS)

Mei, G.T.Y.

1986-01-01

The primary object of this study was to investigate the relations between dosimeter response and skin dose resulting from beta-particle irradiation. This object was achieved by combining evaluation of beta-source energy spectra, calculation of flux energy spectra, and employment of a Monte-Carlo electron-transport computer program for determination of depth-dose distribution in multislab geometries. Intermediate results from three steps of evaluation were compared individually with experimental data or with other theoretical results and showed excellent agreement. The combined method is applicable for the electron agreement. The combined method is applicable for the electron energy range of 1 keV to 5 MeV for both monoenergetic electrons and energy-distributed electrons. Determination of dosimeter response - skin dose relationships for homogeneous atmospheric beta-particle sources and for two specific configurations of LiF TLD's have been carried out in this study. Information based on these calculations is of value in designing beta-particle dosimeters as well as in assessing potential occupational and public health risks associated with the nuclear power industry

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

Energy Technology Data Exchange (ETDEWEB)

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

2012-08-15

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

Thermoluminescent dosemeters characterization for patient dosimetry in diagnostic radiology preliminary results;Caracterizacao de dosimetros termoluminescentes para dosimetria de pacientes em radiodiagnostico - resultados iniciais

Energy Technology Data Exchange (ETDEWEB)

Castro, William J.; Squair, Peterson L. [Faculdade Novo Rumo, Belo Horizonte, MG (Brazil); Centro de Desenvolvimento de Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Gonzaga, Natalia B. [Universidade Unincor, Belo Horizonte, MG (Brazil); Centro de Desenvolvimento de Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Nogueira, Maria S.; Silva, Teogenes A. da [Centro de Desenvolvimento de Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2009-07-01

The determination of the metrological characteristics of thermoluminescent (TL) dosimeters plays an important role in dosimetry of patients submitted to x-ray examinations for diagnostic purpose. Entrance surface doses can be measured with TL dosimeters to verify the compliance with the diagnostic reference levels. Organ doses can be estimated through TL measurements in an anthropomorphic phantom which it allows the radiation risk assessment. In this work, LiF:Mg,Ti (TLD-100) rod and chip thermoluminescent dosimeters were characterized considering their use for patient dosimetry in computerized tomography and mammography. Preliminary results showed that TL dosimeters have a response reproducibility of 7.8% and 4.8% and homogeneity of 18.4% and 6.5% for rod and chip shapes, respectively. (author)

The study on production of CaSO4 (Dy) dosimeters

International Nuclear Information System (INIS)

Sriratchatchaval, V.

1989-05-01

The purpose of this experiment is to find out the techniques of preparation and production and to study the characteristic of Thermoluminescence Dosimeter (TLD); CaSO 4 (Dy). This dosimeter is produced as pellets with 1.0 mm thickness and diameter 4.8 mm, which is suitable for gamma rays and X-rays detector. CeSO 4 (Dy) is prepared by adding Dy 2 O 3 (0.2 mole %Dy) to CaSO 4 .2H 2 O then taking this mixture to crystallize in conc. H 2 SO 4 at 300 0 C responds linearly to gamma rays in the range of 0.01-100 mGy and gives the highest peak at 205 0 C. This TLD is fading 3% per month, low sensitivity to light and the response of signal depends on the energy level of gamma rays

Exposure times and ratio of readings produced by irradiation of thermoluminescence dosemeters in PTB neutron standard fields between 0.1 MeV and 19 MeV

International Nuclear Information System (INIS)

Jahr, R.; Guldbakke, S.; Cosack, M.

1979-06-01

6 LiF and 7 LiF thermoluminescence dosimeters (TLD) irradiated in a standard field of monoenergetic neutrons (Esub(n) = 0.1 MeV to 19 MeV), respond as well to the photon as to the neutron component of this radiation field. The ratio of the two TLD readings as well as the duration of irradiation required to obtain a preset TLD reading are calculated as a function of the neutron energy. (orig.) [de

Neutron area monitor with TLD pairs

International Nuclear Information System (INIS)

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

2011-11-01

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

The application of thermoluminescence dosimeters to studies of released activity distributions

International Nuclear Information System (INIS)

Ruden, B.I.

1969-06-01

In this report the theoretical conditions necessary for the study of the behaviour of released activity by the use of CaSO 4 : Mn thermoluminescence dosimeters are considered. A method is derived for calculating exposure distributions from drifting volume activity. The correlation between exposure distributions and concentration distributions is discussed. One of thirty experiments where Br 82 was released into water through a nozzle some metres above the bottom is described. The resulting exposure distribution was measured in a vertical plane at distances of 10, 50 and 200 metres by CaSO 4 : Mn thermoluminescence dosimeters. The measured exposures are described and discussed. The advantages and disadvantages of the technique are compared with other methods. The method using exposure measurements for the study of active release in water has given satisfactory results in practice. The measurements have been made at concentration levels which are considerably below that permissible for drinking water according to the recommendations by ICRPA special advantage with this method is that the measurements can be made simultaneously at a large number of places and that integration is possible over sufficiently long periods of time. An experiment is described where Ar 41 was released in free air at a height of one metre above ground and the resulting exposure distribution was measured in a vertical plane at 100 and 250 metres distance by CaSO 4 : Mn thermoluminescence dosimeters. Shielding problems in connection with the experiments have been small since the method permits the measurement of very small doses. An account is given of the possibility of using the beta emitting isotope Kr 85 instead of the gamma emitting Ar 41 for diffusion experiments in air. The results obtained from some experiments are presented and discussed. The thermoluminescent signal from the dosimeters are, at the same concentration and exposure time, 2.5 times greater for Kr 85 than for Ar 41. The Kr

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

International Nuclear Information System (INIS)

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

1999-01-01

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

Similarities and differences between two different types of the thermoluminescence dosimeters belonging to the LiF family

Energy Technology Data Exchange (ETDEWEB)

Sadek, A.M. [Ionizing Radiation Metrology Department, National Institute for Standards, Giza (Egypt); Khamis, F. [Physics Department, University of Tripoli, Tripoli (Lebanon); Polymeris, George S. [Institute of Nuclear Science, Ankara University, Besevler, Ankara (Turkey); Carinou, E. [Greek Atomic Energy Commission (GAEC), Ag. Paraskevi (Greece); Kitis, G. [Nuclear Physics and Elementary Particles Physics Section, Physics Department, Aristotle University of Thessaloniki, Makedonia (Greece)

2017-01-15

The kinetic parameters of the glow-peaks of Harshaw - LiF:Mg, Ti (TLD) and Poland - LiF:Mg,Ti (MTS) dosimeters were investigated at different dose levels using the computerized glow-curve deconvolution (CGCD) algorithm. The results showed that the glow-curve structure and the kinetic parameters of the MTS - 6 and the TLD dosimeter are identical. In addition, the glow-curve structure and the kinetic parameters of the MTS - N and MTS - 7 dosimeters. However, unusual low activation energy (∝1.67 eV) and frequency factor (∝10{sup 15} s{sup -1}) values were detected for peak 5 of MTS - N, and MTS - 7 at the 50 Gy dose-level. Moreover, unlike the activation energy and the frequency factor of peak 5 of the TLD dosimeters, the activation energy and the frequency factor of peak 5 of MTS - N and MTS - 7 are substantially dependent on the absorbed dose level. The results also showed that peak 2 of the same dosimeters has also unusual low activation energy and frequency factor values. However, these values showed high stability over the different dose levels. The explanations of these unusual behaviors of peak 5 were discussed and a correlation between peak 2 and peak 5 was pointed out. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Biokinetics of radiolabeled Iodophenylpentadecanoic acid (I-123-IPPA) and thallium-201 in a rabbit model of chronic myocardial infarction measured using a series of thermoluminescent dosimeters

Science.gov (United States)

Medich, David Christopher

1997-09-01

The biokinetics of Iodophenylpentadecanoic acid (123I-IPPA) during a chronic period of myocardial infarction were determined and compared to 201Tl. IPPA was assessed as a perfusion and metabolic tracer in the scintigraphic diagnosis of coronary artery disease. The myocardial clearance kinetics were measured by placing a series of thermoluminescent dosimeters (TLDs) on normal and infarcted tissue to measure the local myocardial activity content over time. The arterial blood pool activity was fit to a bi-exponential function for 201Tl and a tri-exponential function for 123I-IPPA to estimate the left ventricle contribution to TLD response. At equilibrium, the blood pool contribution was estimated experimentally to be less than 5% of the total TLD response. The method was unable to resolve the initial uptake of the imaging agent due in part to the 2 minute TLD response integration time and in part to the 30 second lag time for the first TLD placement. A noticeable disparity was observed between the tracer concentrations of IPPA in normal and ischemic tissue of approximately 2:1. The fitting parameters (representing the biokinetic eigenvalue rate constants) were related to the fundamental rate constants of a recycling biokinetic model. The myocardial IPPA content within normal tissue was elevated after approximately 130 minutes post injection. This phenomenon was observed in all but one (950215) of the IPPA TLD kinetics curves.

Internal background build-up measurements in CaF2:Mn thermoluminescent dosimeters

International Nuclear Information System (INIS)

Balasybrahmanyam, V.; Measures, M.P.

1977-01-01

Some problems associated with the internal background build-up (IBB) of CaF 2 :Mn thermoluminescent dosimeters are reported. As a result of an investigation of batches of the EG and G model 15 dosimeter it is considered that measurements using this type of dosimeter are accurate and reproducible once the IBB has been determined. However, the use of the Manufacturer's claimed average of 0.064 mR/day can lead to erroneous results when determining environmental background dose rates. The authors therefore urge a rigid quality control program by the manufacturer and suggest that purchasers should be supplied with IBB information of each batch of dosimeters. Meanwhile each user should be aware of the IBB problem and be extremely cautious when using these dosimeters for environmental monitoring purposes. (U.K.)

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

International Nuclear Information System (INIS)

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

2014-01-01

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

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)

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)

External gamma radiation monitoring in the environs of Kaiga Generating Station (KGS), using thermoluminescent dosimeters, during the period 1989-2003

International Nuclear Information System (INIS)

Basu, A.S.; Chougaonkar, M.P.; Mayya, Y.S.; Puranik, V.D.; Reji, T.K.; Ravi, P.M.; Hegde, A.G.

2005-05-01

This publication reports the results of external gamma radiation monitoring using Thermoluminescent Dosimeters (TLDs), in the environs of Kaiga Generating Station (KGS) during its preoperational survey between October 1989 and June 1998. The report also presents quarterly and annual values of air dose during the operational phase of the station between July 1998 and Dec. 2003 around the environmcnt of KGS. The results of TLD analysis, during the period October 1989-June 1998, indicate that the average annual air dose for the locations monitored, was 502± 91 μGy/a. The general background of the environs around Kaiga during the operational period, i.e. July 1998 and Dec. 2003, between 2.3 km. to 32km. has been found to be 509±74 μGy/a. The report discusses the methodology and different analyses carried out. (author)

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

Science.gov (United States)

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

1984-05-01

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

Study and characterization of dosimeter LiF:Mg,Cu,P for using in aeronautical dosimetry

International Nuclear Information System (INIS)

Flavia, Hanna; Federico, Claudio; Lelis, Odair; Pereira, Heloisa; Pereira, Marlon

2014-01-01

The effects of cosmic ionizing radiation incidents in aircraft components and crews has been a source of concern and motivated increasingly studies and improvements in the area. The low dose rates involved in this radiation field in aircraft flight altitudes imply Dosimetric necessity of using materials with high efficiency of detection, to enable studies lower cumulative doses resulting in shorter routes or lower altitude. The choice of thermoluminescent dosimeters LiF: Mg, Cu, P was done by having a detection efficiency of about fifteen times higher than its predecessor (LiF: Mg, Ti), and therefore, applied in very low doses dosimetry, and environmental dosimetry . The implementation of the use of pair dosimetric TLD-600H and 700H-TLD will serve as support for testing and studies on the effects of low doses of cosmic radiation in environmental dosimetry applied in the aviation environment in the usual flight altitudes. In this paper are presented the results of development of a methodology for dosimetry low doses of gamma radiation and neutrons using the pair dosimetric TLD-600H and 700H-TLD. The results demonstrate a sensitivity of dosimeters well above the dosimeters LiF: Mg, Ti confirming its suitability for dosimetry of low doses

Dose Measurements of Parotid Glands and Spinal Cord in Conventional Treatment of Nasopharyngeal Carcinoma Using RANDO Phantom and Thermoluminescent Dosimeters

Directory of Open Access Journals (Sweden)

Mohammad Taghi Bahreyni Toossi

2015-07-01

Full Text Available Introduction Radiotherapy is regarded as the first treatment of choice for nasopharyngeal carcinoma. Despite the advantages of radiotherapy, patients may suffer from a wide range of side-effects due to the presence of many sensitive normal tissues in these regions. If the absorbed dose exceeds the tolerance level in parotid glands and the spinal cord, myelopathy, Lhermitte's sign and xerostomia cannot be avoided. Materials and Methods The head and neck of a RANDO phantom (reference man, which was regarded as a hypothetical patient with nasopharyngeal carcinoma was evaluated. The full course of treatment consisted of three phases. At the beginning of each phase, an oncologist marked conventional fields on the RANDO phantom using a simulator. For measuring the absorbed dose, Thermoluminescent Dosimeters(TLD chips (TLD-100 were utilized.The absorbed dose by TLDs was read by Harshaw 3500 TLD reader. Results The total absorbed dose was calculated by measuring the absorbed dose in each phase, multiplied by the fraction numbers of each phase; the obtained values were summed up. The results showed that the received doses by spinal cord ranged from 15.24 to 54.56 Gy. Also, the absorbed dose of parotid glands was approximately 39.23 Gy. Conclusion Considering the minimum tolerance dose the absorbed doses in the spinal cord and parotid glands were above the tolerance level. The incidence rate of xerostomia and myelopathy were higher in patients, treated by conventional methods.

Evaluation of the response to xenon-133 radiations by thermoluminescent dosimeters used during the accident at Three Mile Island.

Science.gov (United States)

Riley, R J; Zanzonico, P B; Masterson, M E; St Germain, J M; Laughlin, J S

1982-03-01

An evaluation is presented of the accuracy and sensitivity of three types of TLD's used during the accident at the Three Mile Island Nuclear Station. This evaluation indicated that, due to the method of calibration, all the dosimeters over-responded to 133Xe radiations. The response ranged from slightly above unity to almost two. Exposures of the TLD's were of two types, namely, the characteristic X-rays either were or were not filtered from the beam. The angular sensitivity of the dosimeters is also reported.

Characterization of MOSFET dosimeters for low-dose measurements in maxillofacial anthropomorphic phantoms.

Science.gov (United States)

Koivisto, Juha H; Wolff, Jan E; Kiljunen, Timo; Schulze, Dirk; Kortesniemi, Mika

2015-07-08

The aims of this study were to characterize reinforced metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters to assess the measurement uncertainty, single exposure low-dose limit with acceptable accuracy, and the number of exposures required to attain the corresponding limit of the thermoluminescent dosimeters (TLD). The second aim was to characterize MOSFET dosimeter sensitivities for two dental photon energy ranges, dose dependency, dose rate dependency, and accumulated dose dependency. A further aim was to compare the performance of MOSFETs with those of TLDs in an anthropomorphic phantom head using a dentomaxillofacial CBCT device. The uncertainty was assessed by exposing 20 MOSFETs and a Barracuda MPD reference dosimeter. The MOSFET dosimeter sensitivities were evaluated for two photon energy ranges (50-90 kVp) using a constant dose and polymethylmethacrylate backscatter material. MOSFET and TLD comparative point-dose measurements were performed on an anthropomorphic phantom that was exposed with a clinical CBCT protocol. The MOSFET single exposure low dose limit (25% uncertainty, k = 2) was 1.69 mGy. An averaging of eight MOSFET exposures was required to attain the corresponding TLD (0.3 mGy) low-dose limit. The sensitivity was 3.09 ± 0.13 mV/mGy independently of the photon energy used. The MOSFET dosimeters did not present dose or dose rate sensitivity but, however, presented a 1% decrease of sensitivity per 1000 mV for accumulated threshold voltages between 8300 mV and 17500 mV. The point doses in an anthropomorphic phantom ranged for MOSFETs between 0.24 mGy and 2.29 mGy and for TLDs between 0.25 and 2.09 mGy, respectively. The mean difference was -8%. The MOSFET dosimeters presented statistically insignificant energy dependency. By averaging multiple exposures, the MOSFET dosimeters can achieve a TLD-comparable low-dose limit and constitute a feasible method for diagnostic dosimetry using anthropomorphic phantoms. However, for single in

The Properties of CaSO{sub 4}: Mn Thermoluminescence Dosimeters

Energy Technology Data Exchange (ETDEWEB)

Bjaerngard, Bengt

1963-06-15

The properties of the radio thermoluminescence of CaSO{sub 4}:Mn, used for dosimetry of gamma and roentgen radiation, have been investigated. The light yield of the luminophore has been determined to 1.5 percent for 1 MeV gamma radiation. The dependence of the thermoluminescence light sum on the exposure, the exposure rate, and the exposure time can qualitatively be described by the first order process model, modified by a broad energy distribution of the electron trap depths. Some applications are discussed. The cheapness of the dosimeters, the convenient read-out, and the broad range of measurable exposures suggest that CaSO{sub 4}:Mn can be a valuable complement to other dosimetry systems.

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

International Nuclear Information System (INIS)

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

2011-01-01

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

Thermoluminescent dosimetry in fluoroscopy of pediatric patients

International Nuclear Information System (INIS)

Garcia V, E.; Azorin N, J.; Hidalgo T, S.; Dies S, P.

2016-10-01

The use of thermoluminescent dosimeters in the area of medical physics and especially in radiology is of paramount importance to guarantee the quality of a particular study, which for this reason the need to verify by means of measurements of peripheral dose in studies of esophagogastroduodenal series by fluoroscopy using TLD of LiF:Mg, Ti. For this the necessary measurements were carried out directly in patients of the Children s Hospital of Mexico Federico Gomez. Previously characterized the dosimeters were used the graphs of the linear equation to obtain the absorbed dose of each dosimeter and was found that the values of the absorbed dose in each patient changes for various reasons like the anatomy, thickness of the tissues, age and exposure time during the study and was verify that none of the studies performed on patients exceeded dose levels that could affect healthy organs. (Author)

Peripheral dose measurements with diode and thermoluminescence dosimeters for intensity modulated radiotherapy delivered with conventional and un-conventional linear accelerator

International Nuclear Information System (INIS)

Kinhikar, Rajesh; Tambe, Chandrashekhar; Kadam, Sudarshan; Deshpande, Deepak; Gamre, Poonam; Biju, George; Suryaprakash; Magai, C.S.; Shrivastava, Shyam; Dhote, Dipak

2013-01-01

The objective of this paper was to measure the peripheral dose (PD) with diode and thermoluminescence dosimeter (TLD) for intensity modulated radiotherapy (IMRT) with linear accelerator (conventional LINAC), and tomotherapy (novel LINAC). Ten patients each were selected from Trilogy dual-energy and from Hi-Art II tomotherapy. Two diodes were kept at 20 and 25 cm from treatment field edge. TLDs (LiF:MgTi) were also kept at same distance. TLDs were also kept at 5, 10, and 15 cm from field edge. The TLDs were read with REXON reader. The readings at the respective distance were recorded for both diode and TLD. The PD was estimated by taking the ratio of measured dose at the particular distance to the prescription dose. PD was then compared with diode and TLD for LINAC and tomotherapy. Mean PD for LINAC with TLD and diode was 2.52 cGy (SD 0.69), 2.07 cGy (SD 0.88) at 20 cm, respectively, while at 25 cm, it was 1.94 cGy (SD 0.58) and 1.5 cGy (SD 0.75), respectively. Mean PD for tomotherapy with TLD and diode was 1.681 cGy (SD 0.53) and 1.58 (SD 0.44) at 20 cm, respectively. The PD was 1.24 cGy (SD 0.42) and 1.088 cGy (SD 0.35) at 25 cm, respectively, for tomotherapy. Overall, PD from tomotherapy was found lower than LINAC by the factor of 1.2-1.5 PD measurement is essential to find out the potential of secondary cancer. PD for both (conventional LINAC) and novel LINACs (tomotherapy) were measured and compared with each other. The comparison of the values for PD presented in this work and those published in the literature is difficult because of the different experimental conditions. The diode and TLD readings were reproducible and both the detector readings were comparable. (author)

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

International Nuclear Information System (INIS)

Struckmeyer, R.; McNamara, N.

1990-03-01

This report presents the results of the NRC Direct Radiation Monitoring Network for the fourth quarter of 1989. It provides the ambient radiation levels measured in the vicinity of 75 sites throughout the United States. In addition, it describes the equipment used, monitoring station selection criteria, characterization of the dosimeter response, calibration procedures, statistical methods, intercomparison, and quality assurance program

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.

Evaluation and comparison of absorbed dose for electron beams by LiF and diamond dosimeters

International Nuclear Information System (INIS)

Mosia, G.J.; Chamberlain, A.C.

2007-01-01

The absorbed dose response of LiF and diamond thermoluminescent dosimeters (TLDs), calibrated in 60 Co γ-rays, has been determined using the MCNP4B Monte Carlo code system in mono-energetic megavoltage electron beams from 5 to 20 MeV. Evaluation of the dose responses was done against the dose responses of published works by other investigators. Dose responses of both dosimeters were compared to establish if any relation exists between them. The dosimeters were irradiated in a water phantom with the centre of their top surfaces (0.32x0.32 cm 2 ), placed at d max perpendicular to the radiation beam on the central axis. For LiF TLD, dose responses ranged from 0.945±0.017 to 0.997±0.011. For the diamond TLD, the dose response ranged from 0.940±0.017 to 1.018±0.011. To correct for dose responses by both dosimeters, energy correction factors were generated from dose response results of both TLDs. For LiF TLD, these correction factors ranged from 1.003 up to 1.058 and for diamond TLD the factors ranged from 0.982 up to 1.064. The results show that diamond TLDs can be used in the place of the well-established LiF TLDs and that Monte Carlo code systems can be used in dose determinations for radiotherapy treatment planning

The application of an automated thermoluminescence dosimetry system to environmental γ-dosimetry

International Nuclear Information System (INIS)

Jones, A.R.

1977-07-01

A personnel monitoring system comprising thermoluminescent dosimeters (TLDs) and an automatic TLD reader has been applied to environmental gamma dosimetry. For this purpose the accuracy of measurement at low exposures (10 to 100 mR) acquired over long periods (3 or 12 months) is important. To improve the accuracy and reliability of the system for this application the following steps were taken: the dosimeters were sensitized by irradiation with γ-rays and annealed while being irradiated with UV light; the sensitivity of each, identified dosimeter was measured and used to correct exposure measurements; the gasketted holders were modified to contain TLDs mounted on two identified plaques. Measurements of linearity, variability (with and without individual calibration) fading and energy dependence are presented. (author)

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

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

Statistical methods to evaluate thermoluminescence ionizing radiation dosimetry data

International Nuclear Information System (INIS)

Segre, Nadia; Matoso, Erika; Fagundes, Rosane Correa

2011-01-01

Ionizing radiation levels, evaluated through the exposure of CaF 2 :Dy thermoluminescence dosimeters (TLD- 200), have been monitored at Centro Experimental Aramar (CEA), located at Ipero in Sao Paulo state, Brazil, since 1991 resulting in a large amount of measurements until 2009 (more than 2,000). The data amount associated with measurements dispersion, since every process has deviation, reinforces the utilization of statistical tools to evaluate the results, procedure also imposed by the Brazilian Standard CNEN-NN-3.01/PR- 3.01-008 which regulates the radiometric environmental monitoring. Thermoluminescence ionizing radiation dosimetry data are statistically compared in order to evaluate potential CEA's activities environmental impact. The statistical tools discussed in this work are box plots, control charts and analysis of variance. (author)

A method for reducing energy dependence of thermoluminescence dosimeter response by means of filters

International Nuclear Information System (INIS)

Bapat, V.N.

1980-01-01

This work describes the application of the method of partial surface shielding for reducing the energy dependence of the X-ray and γ-ray response of a dosimeter containing a CaSO 4 :Dy thermoluminescent phosphor mixed with KCl. in pellet form. Results are given of approximate computation of filter combinations that accomplish this aim, and of experimental verifications. Incorporation of the described filter combination makes it possible to use this relatively sensitive dosimeter for environmental radiation monitoring. A similar approach could be applied to any type of dosimeter in the form of a thin pellet or wafer. (author)

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

Energy Technology Data Exchange (ETDEWEB)

Bonzi, E. V.; Mainardi, R. T. [Universidad Nacional de Cordoba, Facultad de Matematica, Astronomia y Fisica, Av. Haya de la Torre y Av. Medina Allende s/n, Ciudad Universitaria, Cordoba (Argentina); Germanier, A. [Ministerio de Ciencia y Tecnologia, Ceprocor, Unidad de Estudios Fisicos, Alvarez de Arenas 230, X5004AAP Barrio Juniors, Cordoba (Argentina); Delgado, V. [Universidad Complutense de Madrid, Departamento de Fisica Medica, Ciudad Universitaria, 28040 Madrid (Spain)

2011-10-15

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

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

International Nuclear Information System (INIS)

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

2004-01-01

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

Dose profile for electron beams obtained with CaSO{sub 4}:Ce,Eu thermoluminescent dosimeters; Perfil de dose de feixes de eletrons obtidos com dosimetros termoluminescentes de CaSO{sub 4}:Ce,Eu

Energy Technology Data Exchange (ETDEWEB)

Nunes, Maira G.; Rodrigues, Leticia L.C., E-mail: mgnunes@ipen.br [Instituto de Pesquisas Energerticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2012-12-15

The calcium sulphate activated with cerium and europium (CaSO{sub 4}:Ce,Eu) thermoluminescent dosimeters (TLD) recently developed at Nuclear and Energy Research Institute as well as the calcium sulphate activated with dysprosium (CaSO{sub 4}: Dy) and lithium fluoride activated with magnesium and titanium, (LiF:Mg,Ti; TLD-100) TLDs, with long term applications in dosimetry and considered as standards, were used to obtain the dose profile for 3.43, 5.48, 8.27 and 11.67 MeV electron beams generated by a linear accelerator Clinac 2100-C (Varian) in the reference conditions defined by the TRS-398 code of practice. The routine dosimetry of the electron beams, performed with a calibrated ionization chamber, ensures that the electron beams fulfill the requirements of flatness and symmetry established in this code of practice. Thus, as the TRS-398 Code of Practice requirements are fulfilled by the measurements performed with the new TLD type, CaSO{sub 4}:Ce,Eu may be applied in clinical dosimetry of high energy electron beams. (author)

Manufacturing polycrystalline pellets of natural quartz for applications in thermoluminescence dosimetry

Energy Technology Data Exchange (ETDEWEB)

Carvalho Junior, Alvaro Barbosa de; Khoury, Helen Jamil [Federal University of Pernambuco (UFPE), Recife, PE (Brazil). Department of Nuclear Energy; Barros, Thiago Fernandes; Guzzo, Pedro Luiz [Federal University of Pernambuco (UFPE), Recife, PE (Brazil). Department of Mining Engineering

2012-07-15

This paper describes the manufacturing process of quartz-pellets and shows their potential use as thermoluminescence dosimeters (TLD) for those applications where low-levels of ionising radiation are present. Two batches of cold-pressed pellets were produced and their resistance were evaluated by vibration tests and weight-loss measurements. The batch manufactured with 75 Multiplication-Sign 150 Micro-Sign m particles showed enough resistance to be employed as TLD. The dosimetric properties of the 310 Degree-Sign C peak appearing in the glow curves of these pellets were characterized together with commercial TLD-100 units using {gamma}- and X-ray beams with different energies. The uncertainties related to reproducibility and stability of the TL signal were better than 10%. The sensitivity and the linearity of the TL response of quartz-pellets were better than that measured for TLD-100 for doses ranging from 0.5 to 200mGy. The energy dependence of the quartz-pellets was higher than that of TLD-100 but it cannot be considered a restriction to their use in clinical procedures and industrial applications. (author)

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

International Nuclear Information System (INIS)

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

2005-01-01

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

Comparative study of thermoluminescent, radiophotoluminescent and photographic dosemeters

International Nuclear Information System (INIS)

Deus, S.F.

1976-01-01

Comparison was made between the response of three differents dosimetric systems, namely, photographic, thermoluminescent (TL) and radiophotoluminescent (RPL). The comparison was divided in two parts. The first was carried out in known radiation conditions (exposure, normal incidence, energy) and under controlled environment (approximately 27 0 C temperature, approximately 70% relative humidity). Under these conditions, the response as a function of exposure and energy, the relation of the linearity to the energy, the lowest detectable exposure, and the reproducibility, were studied. The response against esposure at 37 KeVef and at 1 MeV was found to be linear in the region of interest to routine personnel dosimetry for all dosimeters except for the filmes. In the second part, the relative response of the dosimeters was verified under the uncontrolled conditions of personnel dosimetry. As the CaSO 4 :Dy is the most sensitive dosimeter, comparison was made using this dosimeter as the standard, in which case one finds that 20 of 29 TLD-100 dosimeters give the same reading within 30%, 13 of 29 RPL dosimeters agree within 30%, and only 3 of 29 films fall within 30% [pt

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

International Nuclear Information System (INIS)

Mora, Patricia; Porras Chaverria, Mariela

2008-01-01

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

Nuclear accident dosimeter designed for use with the Panasonic TLD system

International Nuclear Information System (INIS)

Hankins, D.E.

1985-01-01

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

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

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)

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-01-22

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

Calculation of dose distribution in compressible breast tissues using finite element modeling, Monte Carlo simulation and thermoluminescence dosimeters

Science.gov (United States)

Mohammadyari, Parvin; Faghihi, Reza; Mosleh-Shirazi, Mohammad Amin; Lotfi, Mehrzad; Rahim Hematiyan, Mohammad; Koontz, Craig; Meigooni, Ali S.

2015-12-01

Compression is a technique to immobilize the target or improve the dose distribution within the treatment volume during different irradiation techniques such as AccuBoost® brachytherapy. However, there is no systematic method for determination of dose distribution for uncompressed tissue after irradiation under compression. In this study, the mechanical behavior of breast tissue between compressed and uncompressed states was investigated. With that, a novel method was developed to determine the dose distribution in uncompressed tissue after irradiation of compressed breast tissue. Dosimetry was performed using two different methods, namely, Monte Carlo simulations using the MCNP5 code and measurements using thermoluminescent dosimeters (TLD). The displacement of the breast elements was simulated using a finite element model and calculated using ABAQUS software. From these results, the 3D dose distribution in uncompressed tissue was determined. The geometry of the model was constructed from magnetic resonance images of six different women volunteers. The mechanical properties were modeled by using the Mooney-Rivlin hyperelastic material model. Experimental dosimetry was performed by placing the TLD chips into the polyvinyl alcohol breast equivalent phantom. The results determined that the nodal displacements, due to the gravitational force and the 60 Newton compression forces (with 43% contraction in the loading direction and 37% expansion in the orthogonal direction) were determined. Finally, a comparison of the experimental data and the simulated data showed agreement within 11.5%  ±  5.9%.

Calculation of dose distribution in compressible breast tissues using finite element modeling, Monte Carlo simulation and thermoluminescence dosimeters

International Nuclear Information System (INIS)

Mohammadyari, Parvin; Faghihi, Reza; Mosleh-Shirazi, Mohammad Amin; Lotfi, Mehrzad; Hematiyan, Mohammad Rahim; Koontz, Craig; Meigooni, Ali S

2015-01-01

Compression is a technique to immobilize the target or improve the dose distribution within the treatment volume during different irradiation techniques such as AccuBoost ® brachytherapy. However, there is no systematic method for determination of dose distribution for uncompressed tissue after irradiation under compression. In this study, the mechanical behavior of breast tissue between compressed and uncompressed states was investigated. With that, a novel method was developed to determine the dose distribution in uncompressed tissue after irradiation of compressed breast tissue. Dosimetry was performed using two different methods, namely, Monte Carlo simulations using the MCNP5 code and measurements using thermoluminescent dosimeters (TLD). The displacement of the breast elements was simulated using a finite element model and calculated using ABAQUS software. From these results, the 3D dose distribution in uncompressed tissue was determined. The geometry of the model was constructed from magnetic resonance images of six different women volunteers. The mechanical properties were modeled by using the Mooney–Rivlin hyperelastic material model. Experimental dosimetry was performed by placing the TLD chips into the polyvinyl alcohol breast equivalent phantom. The results determined that the nodal displacements, due to the gravitational force and the 60 Newton compression forces (with 43% contraction in the loading direction and 37% expansion in the orthogonal direction) were determined. Finally, a comparison of the experimental data and the simulated data showed agreement within 11.5%  ±  5.9%. (paper)

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

Science.gov (United States)

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

2016-03-01

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

THERMOLUMINESCENT DOSIMETRY

Energy Technology Data Exchange (ETDEWEB)

Malsky, Stanley J.; Amato, Charles G.; Roswit, Bernard

1963-06-15

The performance of CaF/sub 2/: Mn and LiF as thermoluminescent in vivo dosimeters is studied. The facility with which this type of dosimeter can be inserted into the body is discussed. The dosimeter is inserted into the body by trocar or catheter techniques and exposed to radiation; it is then removed and heated, and the thermoluminescence is measured and used as an indication of the absorbed dose. (T.F.H.)

Thermoluminescence dosimetry and its applications in medicine. Part 2: history and applications

International Nuclear Information System (INIS)

Kron, T.

1995-01-01

Thermoluminescence dosimetry (TLD) has been available for dosimetry of ionising radiation for nearly 100 years. The variety of materials and their different physical forms allow the determination of different radiation qualities over a wide range of absorbed dose. This makes TL dosimeters useful in radiation protection where dose levels of μ Gy are monitored as well as in radiotherapy where doses up to several Gray are to be measured. The major advantages of TL detectors are their small physical size and that no cables or auxiliary equipment is required during the dose assessment. TLD is considered to be a good method for point dose measurements in phantoms as well as for in vivo dosimetry on patients during radiotherapy treatment. As an integrative dosimetric technique, it can be applied to personal dosimetry and it lends itself to the determination of dose distributions due to multiple or moving radiation sources (e.g. conformal and dynamic radiotherapy, computed tomography). In addition, TL dosimeters are easy to transport, and they can be mailed. This makes them well suited for intercomparison of doses delivered in different institutions. The present article aims at describing the various applications TLD has found in medicine by taking into consideration the physics and practice of TLD measurements which have been discussed in the first part of this review. 198 refs., 4 tabs., 2 figs

128 slice computed tomography dose profile measurement using thermoluminescent dosimeter

International Nuclear Information System (INIS)

Salehhon, N; Hashim, S; Karim, M K A; Ang, W C; Musa, Y; Bahruddin, N A

2017-01-01

The increasing use of computed tomography (CT) in clinical practice marks the needs to understand the dose descriptor and dose profile. The purposes of the current study were to determine the CT dose index free-in-air (CTDI air ) in 128 slice CT scanner and to evaluate the single scan dose profile (SSDP). Thermoluminescent dosimeters (TLD-100) were used to measure the dose profile of the scanner. There were three sets of CT protocols where the tube potential (kV) setting was manipulated for each protocol while the rest of parameters were kept constant. These protocols were based from routine CT abdominal examinations for male adult abdomen. It was found that the increase of kV settings made the values of CTDI air increased as well. When the kV setting was changed from 80 kV to 120 kV and from 120 kV to 140 kV, the CTDI air values were increased as much as 147.9% and 53.9% respectively. The highest kV setting (140 kV) led to the highest CTDI air value (13.585 mGy). The p -value of less than 0.05 indicated that the results were statistically different. The SSDP showed that when the kV settings were varied, the peak sharpness and height of Gaussian function profiles were affected. The full width at half maximum (FWHM) of dose profiles for all protocols were coincided with the nominal beam width set for the measurements. The findings of the study revealed much information on the characterization and performance of 128 slice CT scanner. (paper)

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)

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

Characterization of MOSFET dosimeters for low‐dose measurements in maxillofacial anthropomorphic phantoms

Science.gov (United States)

Wolff, Jan E.; Kiljunen, Timo; Schulze, Dirk; Kortesniemi, Mika

2015-01-01

The aims of this study were to characterize reinforced metal‐oxide‐semiconductor field‐effect transistor (MOSFET) dosimeters to assess the measurement uncertainty, single exposure low‐dose limit with acceptable accuracy, and the number of exposures required to attain the corresponding limit of the thermoluminescent dosimeters (TLD). The second aim was to characterize MOSFET dosimeter sensitivities for two dental photon energy ranges, dose dependency, dose rate dependency, and accumulated dose dependency. A further aim was to compare the performance of MOSFETs with those of TLDs in an anthropomorphic phantom head using a dentomaxillofacial CBCT device. The uncertainty was assessed by exposing 20 MOSFETs and a Barracuda MPD reference dosimeter. The MOSFET dosimeter sensitivities were evaluated for two photon energy ranges (50–90 kVp) using a constant dose and polymethylmethacrylate backscatter material. MOSFET and TLD comparative point‐dose measurements were performed on an anthropomorphic phantom that was exposed with a clinical CBCT protocol. The MOSFET single exposure low dose limit (25% uncertainty, k=2) was 1.69 mGy. An averaging of eight MOSFET exposures was required to attain the corresponding TLD (0.3 mGy) low‐dose limit. The sensitivity was 3.09±0.13 mV/mGy independently of the photon energy used. The MOSFET dosimeters did not present dose or dose rate sensitivity but, however, presented a 1% decrease of sensitivity per 1000 mV for accumulated threshold voltages between 8300 mV and 17500 mV. The point doses in an anthropomorphic phantom ranged for MOSFETs between 0.24 mGy and 2.29 mGy and for TLDs between 0.25 and 2.09 mGy, respectively. The mean difference was −8%. The MOSFET dosimeters presented statistically insignificant energy dependency. By averaging multiple exposures, the MOSFET dosimeters can achieve a TLD‐comparable low‐dose limit and constitute a feasible method for diagnostic dosimetry using anthropomorphic phantoms. However

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

International Nuclear Information System (INIS)

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

2007-01-01

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

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

International Nuclear Information System (INIS)

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

1985-01-01

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

Thermoluminescence characterisation of chemical vapour deposited diamond films

CERN Document Server

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

2002-01-01

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

Manufacture of thermoluminescent dosimeter of LiF(Mg) by sintherization technique

International Nuclear Information System (INIS)

Borges, V.; Elbern, A.W.

1984-01-01

A technique to produce solid state dosemeters, that can be used in personal dosimetry, using LiF powder is described. Many differents baths of cold compacted and sinterized dosimeters were investigated as a function of the dopant concentration and the sinterization time. Some termoluminescent characteristics were measured, and compared to those of the extruded TLD-100 dosemeters, which are used as an international reference. The experimental methodology and the obtained results, with their respective analyses, are the subject of this paper. (M.A.C.) [pt

An automated thermoluminescence dosimetry (TLD) system

International Nuclear Information System (INIS)

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

1979-01-01

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

A new fully automated TLD badge reader

International Nuclear Information System (INIS)

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

2003-01-01

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

NRC TLD Direct Radiation Monitoring Network

International Nuclear Information System (INIS)

Struckmeyer, R.; McNamara, N.

1992-06-01

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

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

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

International Nuclear Information System (INIS)

Estrada E, D.

2002-01-01

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

Thermoluminescent properties of CVD diamond: applications to ionising radiation dosimetry; Proprietes thermoluminescentes du diamant CVD: applications a la dosimetrie des rayonnements ionisants

Energy Technology Data Exchange (ETDEWEB)

Petitfils, A

2007-09-15

Remarkable properties of synthetic diamond (human soft tissue equivalence, chemical stability, non-toxicity) make this material suitable for medical application as thermoluminescent dosimeter (TLD). This work highlights the interest of this material as radiotherapy TLD. In the first stage of this work, we looked after thermoluminescent (TL) and dosimetric properties of polycrystalline diamond made by Chemically Vapor Deposited (CVD) synthesis. Dosimetric characteristics are satisfactory as TLD for medical application. Luminescence thermal quenching on diamond has been investigated. This phenomenon leads to a decrease of dosimetric TL peak sensitivity when the heating rate increases. The second part of this work analyses the use of synthetic diamond as TLD in radiotherapy. Dose profiles, depth dose distributions and the cartography of an electron beam obtained with our samples are in very good agreement with results from an ionisation chamber. It is clearly shown that CVD) diamond is of interest to check beams of treatment accelerators. The use of these samples in a control of treatment with Intensity Modulated Radiation Therapy underlines good response of synthetic diamond in high dose gradient areas. These results indicate that CVD diamond is a promising material for radiotherapy dosimetry. (author)

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

NARCIS (Netherlands)

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

2014-01-01

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

Dosimetry of Al2O3 optically stimulated luminescent dosimeter at high energy photons and electrons

Science.gov (United States)

Yusof, M. F. Mohd; Joohari, N. A.; Abdullah, R.; Shukor, N. S. Abd; Kadir, A. B. Abd; Isa, N. Mohd

2018-01-01

The linearity of Al2O3 OSL dosimeters (OSLD) were evaluated for dosimetry works in clinical photons and electrons. The measurements were made at a reference depth of Zref according to IAEA TRS 398:2000 codes of practice at 6 and 10 MV photons and 6 and 9 MeV electrons. The measured dose was compared to the thermoluminescence dosimeters (TLD) and ionization chamber commonly used for dosimetry works for higher energy photons and electrons. The results showed that the measured dose in OSL dosimeters were in good agreement with the reported by the ionization chamber in both high energy photons and electrons. A reproducibility test also reported excellent consistency of readings with the OSL at similar energy levels. The overall results confirmed the suitability of OSL dosimeters for dosimetry works involving high energy photons and electrons in radiotherapy.

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

Numerical analysis of thermoluminescence glow curves

International Nuclear Information System (INIS)

Gomez Ros, J. M.; Delgado, A.

1989-01-01

This report presents a method for the numerical analysis of complex thermoluminescence glow curves resolving the individual glow peak components. The method employs first order kinetics analytical expressions and is based In a Marquart-Levenberg minimization procedure. A simplified version of this method for thermoluminescence dosimetry (TLD) is also described and specifically developed to operate whit Lithium Fluoride TLD-100. (Author). 36 refs

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

International Nuclear Information System (INIS)

Norhayati Abdullah; Taiman Kadni

2016-01-01

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

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

CERN Document Server

Kaskanov, G Y

2003-01-01

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

Dosimetric behavior of thermoluminescent dosimeters at low doses in diagnostic radiology; Comportamiento dosimetrico de dosimetros termoluminiscentes a bajas dosis en radiodiagnostico

Energy Technology Data Exchange (ETDEWEB)

Del Sol F, S.; Garcia S, R.; Guzman M, J.; Sanchez G, D.; Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Ramirez R, G. [Hospital Juarez de Mexico, Av. IPN 5160, Col. Magdalena de las Salinas, 07760 Mexico D. F. (Mexico); Gaona, E., E-mail: susi2489@hotmail.com [Universidad Autonoma Metropolitana, Unidad Xochimilco, Calz. del Hueso 1100, Col. Villa Quietud, 04960 Mexico D. F. (Mexico)

2015-10-15

Thermoluminescent (Tl) characteristics of TLD-100, LiF:Mg,Cu,P, and CaSO{sub 4}: Dy the under homogeneous field of X-ray beams of diagnostic irradiation and its verification using thermoluminescent dosimetry is presented. The irradiations were performed utilizing an X-ray beam generated by a Radiology Mexican Company: MRH-II E GMX 325-AF SBV-1 model, with Rotating Anode X-Ray Tube installed in the Hospital Juarez Norte de Mexico in Mexico City. Different thermoluminescent characteristics of dosimetric material were studied, such as, batch homogeneity, Tl glow curve, Tl response as a function of X-ray dose, reproducibility and fading. Materials were calibrated in terms of absorbed dose to the standard calibration distance and positioned in a generic Phantom was used. Dose verification and comparison with the measurements made with that obtained by TLD-100 were analyzed. Preliminary results indicate the dosimetric peak appears at 243, 236 and 277 ± 5 degrees C respectively, these peaks are in agreement with that reported in the literature. Tl glow curve as a function of X-ray dose showed a linearity in the range from 1.76 mGy up to 14.70 mGy for all materials. Fading for a period of one month at room temperature showed low fading LiF:Mg,Cu,P, medium and high for TLD-100 and CaSO{sub 4}: Dy. The results suggest that the three materials are suitable for measurements at low doses in radiodiagnostic, however, for its dosimetric characteristics are most effective for individual applications: personal dosimetry and monitors limb (LiF:Mg,Cu,P), clinical dosimetry and environmental (TLD-100 and CaSO{sub 4}: Dy). (Author)

Thermoluminescent response of Y2O3:Ce,Eu irradiated with X-rays

International Nuclear Information System (INIS)

Sanchez J, F. del R.; Sosa A, M. A.

2017-10-01

The thermoluminescent response of various materials has been studied when irradiated with X-rays, and the parameters that characterize the order of the kinetics of the material, depth of traps and frequency have been determined. The objective of this project was to characterize the thermoluminescent response of dosimeters based on yttrium oxide (Y 2 O 3 ) irradiated with X-rays. To do this, the thermoluminescent response of the Y 2 O 3 :Ce,Eu dosimeter was measured and exposed to an X-ray radiation field; five levels of radiation were used: in the first, a potential of 53.5 kv was used and a working load of 5.6 m As, in the second: 70.0 kv, 12.5 m As; in the third: 81.0 kv, 20.0 m As; in the fourth: 109 kv, 32 m As, in the fifth: 121 kv, 80.0 m As, applying an exposure range between 17.7 and 40 R. The irradiation was performed exposing the sample at 104 cm from the focus of the X-ray tube. To obtain the readings of the thermoluminescent response, a Harshaw TLD 3500 reader was used. The data captured by the reader was processed using the WinREMS software. The deletion protocol was as follows: the dosimeters already read were placed, one hour in the Terlab MA12D muffle at a temperature of (400 ± 1) degrees centigrade, the dosimeters were removed and left at room temperature of 20 degrees centigrade for 20 minutes. Then they were placed in the Binder high temperature oven ED23 at 100 ± 1 centigrade degrees for 2 hours. The brightness curves were de convolved using the WebPlotDigitizer v 3.8 software and the individual peaks of the brightness curves were obtained. We found that: the synthesized materials presented a good thermoluminescent response when irradiated with X-rays. However, only one of the dosimeters, of Yttrium oxide doped with 0.5% Cerium, showed a relatively linear response in the applied dose range. The analysis made to the brightness curve of the Yttrium oxide doped with Cerium at 0.5%, applying the method of the three points for the parameters

Effect of co-doping of sodium on the thermoluminescence dosimetry properties of copper-doped zinc lithium borate glass system

International Nuclear Information System (INIS)

Saidu, A.; Wagiran, H.; Saeed, M.A.; Alajerami, Y.S.M.; Kadir, A.B.A.

2016-01-01

The effect of sodium as a co-dopant on the thermoluminescence (TL) properties of copper-doped zinc lithium borate (ZLB: Cu) subjected to Co-60 gamma radiation is reported in this study. TL intensity is enhanced with the introduction of sodium in ZLB: Cu. The obtained glow curve is simple with a single peak. The annealing procedure and the best heating rate for the proposed thermoluminescent dosimeter (TLD) are established, and the phosphor is reusable. The TL response within the dose range of 0.5–1000 Gy is investigated. The results show that the thermal fading behaviour is improved significantly. - Highlights: • Dosimetry properties of an improved TL dosimeter. • The dosimeter is made of lithium borate, modified with ZnO, doped with CuO and co-doped with Na 2 O. • With addition of Na to Cu in the ZLB host, TL yield and sensitivity has significantly enhanced. • The fading behaviour has also been minimized significantly. • The new material is also characterized with the linear dose response, and good reproducibility behaviour.

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

International Nuclear Information System (INIS)

Kurnia, E; Oetami, H R; Mutiah

1996-01-01

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

NRC TLD [thermoluminescent dosimeter] Direct Radiation Monitoring Network: Progress report, October--December 1988

International Nuclear Information System (INIS)

Struckmeyer, R.; NcNamara, N.

1989-04-01

This report presents the results of the NRC Direct Radiation Monitoring Network for the fourth quarter of 1988. It provides the ambient radiation levels measured in the vicinity of 75 sites throughout the United States. In addition, it describes the equipment used, monitoring station selection criteria, characterization of the dosimeter response, calibration procedures, statistical methods, intercomparison, and quality assurance program. 4 tabs

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

International Nuclear Information System (INIS)

Nariyama, N.

2000-01-01

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

Measurement of dose enhancement close to high atomic number media using optical fibre thermoluminescence dosimeters

International Nuclear Information System (INIS)

Alalawi, Amani I.; Hugtenburg, R.P.; Abdul Rahman, A.T.; Barry, M.A.; Nisbet, A.; Alzimami, Khalid S.; Bradley, D.A.

2014-01-01

Present interest concerns development of a system to measure photoelectron-enhanced dose close to a tissue interface using analogue gold-coated doped silica-fibre thermoluminescence detectors and an X-ray set operating at 250 kVp. Study is made of the dose enhancement factor for various thicknesses of gold; measurements at a total gold thickness of 160 nm (accounting for incident and exiting photons) produces a mean measured dose enhancement factor of 1.33±0.01 To verify results, simulations of the experimental setup have been performed. - Highlights: • Dose enhancement • Thermoluminescence dosimeter • Monte Carlo simulation

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

International Nuclear Information System (INIS)

Flores M, E.

2007-01-01

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

In vivo dosimetry thermoluminescence dosimeters during brachytherapy with a 370 GBq 192Ir source

International Nuclear Information System (INIS)

Cuepers, S.; Piessens, M.; Verbeke, L.; Roelstraete, A.

1995-01-01

When using LiF thermoluminescence dosimeters in brachytherapy, we have to take into account the properties of a high dose rate 192 Ir source (energy spectrum ranging form 9 to 885 keV, steep dose gradient in the vicinity of the source) and these of the dosimeters themselves (supralinearity, reproducibility, size). All these characteristics combine into a set of correction factors which have been determined during in phantom measurements. These results have then been used to measure the dose delivered to organs at risk (e.g. rectum, bladder, etc.) during high dose rate brachytherapy with a 370 GBq 192 Ir source for patients with gynaecological tumors

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.

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

Energy Technology Data Exchange (ETDEWEB)

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

2006-07-01

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

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

International Nuclear Information System (INIS)

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

2006-01-01

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

TLD territorial network in the Czech Republic

Energy Technology Data Exchange (ETDEWEB)

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

1996-12-31

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

Quantitative relations between beta-gamma mixed-field dosimeter responses and dose-equivalent conversion factors according to the testing standard

International Nuclear Information System (INIS)

Gupta, V.P.

1982-08-01

The conventional two-element personnel dosimeters, usually having two thick TLD (thermoluminescent dosimetry) ribbons, are used extensively for radiation protection dosimetry. Many of these dosimeters are used for the measurement of beta and gamma radiation doses received in mixed beta-gamma fields. Severe limitations exist, however, on the relative magnitudes and energies of these fields that may be measured simultaneously. Moreover, due to a well-known energy dependence of these dosimeters, particularly for the beta-radiations, systematic errors will occur whenever the differences in workplaces and calibration radiation energies exist. A simple mathematical approach is presented to estimate the deep and shallow dose equivalent values at different energies for such dosimeters. The formulae correlate the dosimeter responses and dose equivalent conversion factors at different energies by taking into account the guidelines of the adopted ANSI Standard N13.11 and the dosimetry practices followed by most dosimeter processors. This standard is to be used in a mandatory testing program in the United States

Thermoluminescent dosimetry in fluoroscopy of pediatric patients; Dosimetria termoluminiscente en fluoroscopia de pacientes pediatricos

Energy Technology Data Exchange (ETDEWEB)

Garcia V, E.; Azorin N, J. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Departamento de Fisica, San Rafael Atlixco 186, Col. Vicentina, 09340 Ciudad de Mexico (Mexico); Hidalgo T, S.; Dies S, P., E-mail: azorin@xanum.uam.mx [Hospital Infantil de Mexico Federico Gomez, Dr. Marquez 162, Col. Doctores, 06720 Ciudad de Mexico (Mexico)

2016-10-15

The use of thermoluminescent dosimeters in the area of medical physics and especially in radiology is of paramount importance to guarantee the quality of a particular study, which for this reason the need to verify by means of measurements of peripheral dose in studies of esophagogastroduodenal series by fluoroscopy using TLD of LiF:Mg, Ti. For this the necessary measurements were carried out directly in patients of the Children s Hospital of Mexico Federico Gomez. Previously characterized the dosimeters were used the graphs of the linear equation to obtain the absorbed dose of each dosimeter and was found that the values of the absorbed dose in each patient changes for various reasons like the anatomy, thickness of the tissues, age and exposure time during the study and was verify that none of the studies performed on patients exceeded dose levels that could affect healthy organs. (Author)

Diffusion from a Ground Level Point Source Experiment with Thermoluminescence Dosimeters and Kr 85 as Tracer Substance

Energy Technology Data Exchange (ETDEWEB)

Ruden, B I

1969-06-15

In this report the theoretical conditions necessary for the study of the behaviour of released activity by the use of CaSO{sub 4}: Mn thermoluminescence dosimeters are considered. A method is derived for calculating exposure distributions from drifting volume activity. The correlation between exposure distributions and concentration distributions is discussed. One of thirty experiments where Br 82 was released into water through a nozzle some metres above the bottom is described. The resulting exposure distribution was measured in a vertical plane at distances of 10, 50 and 200 metres by CaSO{sub 4}: Mn thermoluminescence dosimeters. The measured exposures are described and discussed. The advantages and disadvantages of the technique are compared with other methods. The method using exposure measurements for the study of active release in water has given satisfactory results in practice. The measurements have been made at concentration levels which are considerably below that permissible for drinking water according to the recommendations by ICRPA special advantage with this method is that the measurements can be made simultaneously at a large number of places and that integration is possible over sufficiently long periods of time. An experiment is described where Ar 41 was released in free air at a height of one metre above ground and the resulting exposure distribution was measured in a vertical plane at 100 and 250 metres distance by CaSO{sub 4}: Mn thermoluminescence dosimeters. Shielding problems in connection with the experiments have been small since the method permits the measurement of very small doses. An account is given of the possibility of using the beta emitting isotope Kr 85 instead of the gamma emitting Ar 41 for diffusion experiments in air. The results obtained from some experiments are presented and discussed. The thermoluminescent signal from the dosimeters are, at the same concentration and exposure time, 2.5 times greater for Kr 85 than for

Thermoluminescence responses of photon- and electron-irradiated lithium potassium borate co-doped with Cu+Mg or Ti+Mg

International Nuclear Information System (INIS)

Alajerami, Y.S.M.; Hashim, S.; Ramli, A.T.; Saleh, M.A.; Saripan, M.I.; Alzimami, K.; Min Ung, Ngie

2013-01-01

New glasses Li 2 CO 3 –K 2 CO 3 –H 3 BO 3 (LKB) co-doped with CuO and MgO, or with TiO 2 and MgO, were synthesized by the chemical quenching technique. The thermoluminescence (TL) responses of LKB:Cu,Mg and LKB:Ti,Mg irradiated with 6 MV photons or 6 MeV electrons were compared in the dose range 0.5–4.0 Gy. The standard commercial dosimeter LiF:Mg,Ti (TLD-100) was used to calibrate the TL reader and as a reference in comparison of the TL properties of the new materials. The dependence of the responses of the new materials on 60 Co dose is linear in the range of 1–1000 Gy. The TL yields of both of the co-doped glasses and TLD-100 are greater for electron irradiation than for photon irradiation. The TL sensitivity of LKB:Ti,Mg is 1.3 times higher than the sensitivity of LKB:Cu,Mg and 12 times less than the sensitivity of TLD-100. The new TL dosimetric materials have low effective atomic numbers, good linearity of the dose responses, excellent signal reproducibility, and a simple glow curve structure. This combination of properties makes them suitable for radiation dosimetry. - Highlights: • Enhancement of about three times has been shown with the increment of MgO. • A comparison was carried out between the TL responses of the prepared dosimeters and TLD-100. • The prepared dosimeters show simple glow curve, low Z material and excellent reproducibility. • The TL measurements show a linear dose response in a long span of exposures. • The electron response shows 1.18 times greater than photon response for the prepared dosimeters

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

International Nuclear Information System (INIS)

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

2000-01-01

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

The thermoluminescence response of Ge-doped flat fibre for proton beam measurements: A preliminary study

International Nuclear Information System (INIS)

Hassan, M F; Fadzil, M S Ahmad; Noor, N Mohd; Abdul Rahman, W N Wan; Tominaga, T; Geso, M; Akasaka, H; Bradley, D A

2017-01-01

The aim of this study was to investigate the thermoluminescence (TL) response of fabricated 2.3 mol% and 6.0 mol% germanium (Ge) doped flat optical fibres to proton irradiation. The fundamental dosimetric characteristics of the fibres have been investigated including dose linearity, reproducibility and fading. The thermoluminescent dosimeters (TLDs) were used as a reference dosimeter to allow the relative response of the fibres. The results show that Ge-doped flat fibres offer excellent dose linearity over the dose range from 1 Gy up to 10 Gy with correlation of determination (R 2 ) of 0.99. The fibres also demonstrated good reproducibility within the standard deviation (SD) of 0.86% to 6.41%. After 96 days post-irradiation, TLD-100 chips gave rise to the least loss in TL signal at around 18% followed by fabricated 2.3 mol% Ge-doped flat fibres about 24%. This preliminary study has demonstrated that the proposed fabricated Ge-doped flat fibre offers a promising potential for use in proton beam measurements. (paper)

Study and characterization of dosimeter LiF:Mg,Cu,P for using in aeronautical dosimetry; Estudo e caracterizacao do dosimetro de LiF:Mg,Cu,P para utilizacao em dosimetria aeronautica

Energy Technology Data Exchange (ETDEWEB)

Flavia, Hanna, E-mail: hannasantana.f@gmail.com [Universidade Paulista (UNIP), Sao Jose dos Campos, SP (Brazil); Federico, Claudio; Lelis, Odair; Pereira, Heloisa; Pereira, Marlon, E-mail: claudiofederico@ieav.cta.br [Instituto de Estudos Avancados (EFA-A/IEAV), Sao Jose dos Campos, SP (Brazil). Div. de Fisica Aplicada

2014-07-01

The effects of cosmic ionizing radiation incidents in aircraft components and crews has been a source of concern and motivated increasingly studies and improvements in the area. The low dose rates involved in this radiation field in aircraft flight altitudes imply Dosimetric necessity of using materials with high efficiency of detection, to enable studies lower cumulative doses resulting in shorter routes or lower altitude. The choice of thermoluminescent dosimeters LiF: Mg, Cu, P was done by having a detection efficiency of about fifteen times higher than its predecessor (LiF: Mg, Ti), and therefore, applied in very low doses dosimetry, and environmental dosimetry . The implementation of the use of pair dosimetric TLD-600H and 700H-TLD will serve as support for testing and studies on the effects of low doses of cosmic radiation in environmental dosimetry applied in the aviation environment in the usual flight altitudes. In this paper are presented the results of development of a methodology for dosimetry low doses of gamma radiation and neutrons using the pair dosimetric TLD-600H and 700H-TLD. The results demonstrate a sensitivity of dosimeters well above the dosimeters LiF: Mg, Ti confirming its suitability for dosimetry of low doses.

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

International Nuclear Information System (INIS)

Sagastibelza Chivite, F.

1980-01-01

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

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

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

In vivo dosimetry thermoluminescence dosimeters during brachytherapy with a 370 GBq {sup 192}Ir source

Energy Technology Data Exchange (ETDEWEB)

Cuepers, S; Piessens, M; Verbeke, L; Roelstraete, A [Onze-Lieve-Vrouw Hospitaal, Aalst (Belgium). Dept. of Radiotherapy and Oncology

1995-12-01

When using LiF thermoluminescence dosimeters in brachytherapy, we have to take into account the properties of a high dose rate {sup 192}Ir source (energy spectrum ranging form 9 to 885 keV, steep dose gradient in the vicinity of the source) and these of the dosimeters themselves (supralinearity, reproducibility, size). All these characteristics combine into a set of correction factors which have been determined during in phantom measurements. These results have then been used to measure the dose delivered to organs at risk (e.g. rectum, bladder, etc.) during high dose rate brachytherapy with a 370 GBq {sup 192}Ir source for patients with gynaecological tumors.

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

A new TLD system for space research

International Nuclear Information System (INIS)

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

1980-06-01

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

New laser technique revives old ideas for thermoluminescence neutron dosimetry

International Nuclear Information System (INIS)

Braeunlich, P.; Brown, M.; Gasiot, J.; Fillard, J.P.

1982-01-01

Laser heating is discussed as a means to evaluate thermoluminescence dosimeters in neutron dosimetry. Direct energy coupling from the photon beam to the phonons of the TL material permits heating of thin layers with rates of temperature increase exceeding 10 4 Ks - 1 . Rapid TLD evaluation will allow the design of dosimetry badges containing a number of different small thin film TLD elements in various orientations and behind appropriate filters, hydrogenous radiators, etc. Desired redundance is readily possible by using back-up TLDs for every specific task. Reading occurs with a scanning laser beam rather than by mechanically manipulating the TLD toward a fixed heat source. Improvements in the signal-to-noise ratio of up to a factor of 1000 are readily obtained. Thus, sensitive thin-film TLDs can be designed with negligible self-shielding for thermal neutrons in albedo applications and with known, nearly energy dependent cavity correction factors for dosimetry in mixed n-#betta# fields. Due to the greatly increased sensitivity possible with fast laser heating, significant advances are expected in the fast neutron dosimetry techniques which are based on hydrogeneous proton radiators or LET-dependent slow peak formation

Measurement of TLD Albedo response on various calibration phantoms

International Nuclear Information System (INIS)

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

1996-01-01

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

Optimization of the preparation method of LiF: Mg, Cu, P and study of its thermoluminescent properties to be used in ionizing radiation dosimetry

International Nuclear Information System (INIS)

Gonzalez M, P.R.

1995-01-01

In this thesis the preparation and dosimetric properties of the thermoluminescence phosphor LiF doped with magnesium, copper and phosphorus are studied. In chapter 1 luminescence phenomenon in solids is described, emphasizing the importance of thermally stimulated luminescence known as thermoluminescence (TL) as well as its application in ionizing radiation dosimetry. The models used to determine the kinetics parameters in the TL phenomenon are described in chapter 2. In chapter 3, the dosimetric characteristics of a TL materials and its requirements for dosimetry are analyzed. The preparation method of LiF: Mg, Cu, P is presented in chapter 4 studying its general characteristics for dosimetry. The concentrations of dopants, glow curve structure, TL response to gamma, beta and alpha exposures are studied along with those of LiF: Mg, Cu, P prepared for other authors and with those of LiF: Mg, Ti (TLD-100). The kinetic parameters of the phosphor were determined by the deconvolution method. Pellets of this new phosphor powder were made by pressing it at room temperature and sintering in inert atmosphere at 700 Centigrade degrees. Dosimetric characteristics of these pellets were also studied. Chapter 5 presents the results and conclusions of this study. The new dosimeter exhibited three peaks in its glow curve at 140, 180 and 220 Centigrade degrees respectively. Its TL response to gamma radiation was linear from 43.5 μ Gy to 100 Gy. This dosimeter is reusable and stable without significant loss of sensitivity. Its sensitivity was about 30 times higher than that of TLD-100. Fading of this dosimeter was negligible at room temperature as well as at body temperature (37 Centigrade degrees), and 65% at 60 Centigrade degrees. In conclusion, this dosimeter meets all the requirements of the ANSI standard. These and other characteristics render this dosimeter useful in diverse applications of radiation dosimetry. (Author)

In vivo dosimetry with semiconductor and thermoluminescent detectors applied to head and neck cancer treatment

International Nuclear Information System (INIS)

Viegas, Claudio Castelo Branco

2003-03-01

In vivo dosimetry in radiotherapy, i. e, the assessment of the doses received by patients during their treatments, permits a verification of the therapy quality. A routine of in vivo dosimetry is, undoubtedly, a direct benefit for the patient. Unfortunately, in Brazil and in Latin America this procedure is still a privilege for only a few patients. This routine is of common application only in developed countries. The aim of this work is to show the viability and implementation of a routine in vivo dosimetry, using diodes semiconductors and thermoluminescent dosimeters (TLD), at the radiotherapy section of the National Institute of Cancer in Brazil, in the case of head and neck cancer treatment. In order to reach that aim, the characteristics of the response of diodes ISORAD-p and LiF:Mg;Ti (TLD-100) thermoluminescent detectors in powder form were determined. The performance of those detectors for in vivo dosimetry was tested using an RANDO Alderson anthropomorfic phantom and, once their adequacy proved for the kind of measurements proposed, they were used for dose assessment in the case of tumour treatments in the head and neck regions, for Cobalt-60 irradiations. (author)

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

Energy Technology Data Exchange (ETDEWEB)

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

2004-07-01

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

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

International Nuclear Information System (INIS)

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

1997-01-01

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

Assessing Doses to Interventional Radiologists Using a Personal Dosimeter Worn Over a Protective Apron

Energy Technology Data Exchange (ETDEWEB)

Stranden, E.; Widmark, A.; Sekse, T. (Buskerud Univ. College, Drammen (Norway))

2008-05-15

Background: Interventional radiologists receive significant radiation doses, and it is important to have simple methods for routine monitoring of their exposure. Purpose: To evaluate the usefulness of a dosimeter worn outside the protective apron for assessments of dose to interventional radiologists. Material and Methods: Assessments of effective dose versus dose to dosimeters worn outside the protective apron were achieved by phantom measurements. Doses outside and under the apron were assessed by phantom measurements and measurements on eight radiologists wearing two routine dosimeters for a 2-month period during ordinary working conditions. Finger doses for the same radiologists were recorded using thermoluminescent dosimeters (TLD; DXT-RAD Extremity dosimeters). Results: Typical values for the ratio between effective dose and dosimeter dose were found to be about 0.02 when the radiologist used a thyroid shield and about 0.03 without. The ratio between the dose to the dosimeter under and outside a protective apron was found to be less than 0.04. There was very good correlation between finger dose and dosimeter dose. Conclusion: A personal dosimeter worn outside a protective apron is a good screening device for dose to the eyes and fingers as well as for effective dose, even though the effective dose is grossly overestimated. Relatively high dose to the fingers and eyes remains undetected by a dosimeter worn under the apron

Assessing Doses to Interventional Radiologists Using a Personal Dosimeter Worn Over a Protective Apron

International Nuclear Information System (INIS)

Stranden, E.; Widmark, A.; Sekse, T.

2008-01-01

Background: Interventional radiologists receive significant radiation doses, and it is important to have simple methods for routine monitoring of their exposure. Purpose: To evaluate the usefulness of a dosimeter worn outside the protective apron for assessments of dose to interventional radiologists. Material and Methods: Assessments of effective dose versus dose to dosimeters worn outside the protective apron were achieved by phantom measurements. Doses outside and under the apron were assessed by phantom measurements and measurements on eight radiologists wearing two routine dosimeters for a 2-month period during ordinary working conditions. Finger doses for the same radiologists were recorded using thermoluminescent dosimeters (TLD; DXT-RAD Extremity dosimeters). Results: Typical values for the ratio between effective dose and dosimeter dose were found to be about 0.02 when the radiologist used a thyroid shield and about 0.03 without. The ratio between the dose to the dosimeter under and outside a protective apron was found to be less than 0.04. There was very good correlation between finger dose and dosimeter dose. Conclusion: A personal dosimeter worn outside a protective apron is a good screening device for dose to the eyes and fingers as well as for effective dose, even though the effective dose is grossly overestimated. Relatively high dose to the fingers and eyes remains undetected by a dosimeter worn under the apron

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

Energy Technology Data Exchange (ETDEWEB)

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

1995-12-01

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

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

International Nuclear Information System (INIS)

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

2014-01-01

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

Instrumentation in thermoluminescence dosimetry

International Nuclear Information System (INIS)

Julius, H.W.

1986-01-01

In the performance of a thermoluminescence dosimetry (TLD) system the equipment plays an important role. Crucial parameters of instrumentation in TLD are discussed in some detail. A review is given of equipment available on the market today - with some emphasis on automation - which is partly based on information from industry and others involved in research and development. (author)

Proposal of a methodology for quality control in thermoluminescent dosimetry laboratory

International Nuclear Information System (INIS)

Feital, Joao Carlos da S.; Almeida, Claudio Domingues de; Bezerra, Marcos A.

2005-01-01

Taken into account that in thermoluminescence dosimetry adequate selection procedures as well as accurate TLD readings are necessary, this paper presents results of methodology that can be applied as part of quality control programs in thermoluminescence dosimetry laboratories. For the experiment, a set of 200 TLDs ( LiF 100 ) were used and 9 from which were selected, a standard source of Cs -137 , a PTW kiln, a TL 'Harshaw' reader - model 5500 operating under the 'Win Rem' software and a Sr 90 / Y 90 'Bicron' irradiator. In the proceeding the selected dosimeters were irradiated and read 28 times during 18 months, then by one of the standard deviation properties, values up to 14 % were found, for a confidence level of 95 %. The results found and the bibliographic data related to the responses (arbitrary reading) in the crystals used in TLDs, have shown that this methodology can be applied in quality control programs. (author)

TLD system for the monitoring of the environmental radioactivity

International Nuclear Information System (INIS)

Stochioiu, Ana; Sahagia, Maria; Tudor, Ion

2008-01-01

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

SU-G-201-08: Energy Response of Thermoluminescent Microcube Dosimeters in Water for Kilovoltage X-Ray Beams

Energy Technology Data Exchange (ETDEWEB)

Di Maso, L; Lawless, M; Culberson, W; DeWerd, L [University of Wisconsin- Madison, Madison, WI (United States)

2016-06-15

Purpose: To characterize the energy dependence for TLD-100 microcubes in water at kilovoltage energies. Methods: TLD-100 microcubes with dimensions of (1 × 1 × 1) mm{sup 3} were irradiated with kilovoltage x-rays in a custom-built thin-window liquid water phantom. The TLD-100 microcubes were held in Virtual Water™ probes and aligned at a 2 cm depth in water. Irradiations were performed using the M-series x-ray beams of energies ranging from 50-250 kVp and normalized to a {sup 60}Co beam located at the UWADCL. Simulations using the EGSnrc Monte Carlo Code System were performed to model the x-ray beams, the {sup 60}Co beam, the water phantom and the dosimeters in the phantom. The egs-chamber user code was used to tally the dose to the TLDs and the dose to water. The measurements and calculations were used to determine the intrinsic energy dependence, absorbed-dose energy dependence, and absorbed-dose sensitivity. These values were compared to TLD-100 chips with dimensions of (3.2 × 0.9 × 0.9) mm{sup 3}. Results: The measured TLD-100 microcube response per dose to water among all investigated x-ray energies had a maximum percent difference of 61% relative to {sup 60}Co. The simulated ratio of dose to water to the dose to TLD had a maximum percent difference of 29% relative to {sup 60}Co. The ratio of dose to TLD to the TLD output had a maximum percent difference of 13% relative to {sup 60}Co. The maximum percent difference for the absorbed-dose sensitivity was 15% more than the used value of 1.41. Conclusion: These results confirm that differences in beam quality have a significant effect on TLD response when irradiated in water. These results also indicated a difference in TLD-100 response between microcube and chip geometries. The intrinsic energy dependence and the absorbed-dose energy dependence deviated up to 10% between TLD-100 microcubes and chips.

Thermoluminescent Dosimeter as the Gamma Component of a Nuclear Accident Dosimeter; Utilisation du Dosimetre Thermoluminescent Comme Element Detecteur Gamma d'un Dosimetre pour les cas d'Accident Nucleaire; 0422 0415 0420 041c 0414 ; Los Detectores de Termoluminiscencia Como Elemento Gammametrico de un Dosimetro para Casos de Accidente Nuclear

Energy Technology Data Exchange (ETDEWEB)

Handloser, J. S. [Edgerton, Germeshausen and Grier, Inc., Santa Barbara, CA (United States)

1965-06-15

Various types of gamma dosimeters have been employed as the gamma-measuring component of accident dosimeters. These have included various types of glass dosimeters, film, chemical dosimeters and polymerization dosimeters. The thermoluminescent dosimeter has notable advantages over these other types. The wide range of the thermoluminescent dosimeter permits it to be used both as a daily monitor for radiation protection purposes and as an accident dosimeter. This concept eliminates the need for special instrumentation for accident dosimeters and allows the well-calibrated instrumentation in daily use to be utilized in the accident dosimeter system. Commonly, the thermoluminescent dosimeter's inherent range is from 5 mr to 100 000 r, with a reproducibility of {+-} 10%. A single-type calcium fluoride dosimeter and associated readout equipment has been designed and manufactured to cover 5 mr to 5000 r. Readout of the dosimeter is accomplished by heating the phosphor and measuring the light output. Six decade readout instruments are available and completely automated systems have been designed. None of the readout equipment requires more than 20 seconds per dosimeter. Another advantage of the thermoluminescent dosimeter is the low neutron response. The neutron response will vary with the type of container and the type of phosphor. One type of calcium fluoride dosimeter has a neutron response of 0.27 x 10{sup -9} rad per n/cm{sup 2}. Two physical forms of the thermoluminescent dosimeter are considered. The first is an internally heated evacuated dosimeter contained in a glass envelope. This dosimeter is about 3/8-in diam.x 2 Vulgar-Fraction-One-Half -in long. The second type consists of a small-bore glass tube with the phosphor sealed inside. This dosimeter is 0.8-mm diam. x 6-mm long. Energy response correction shields have been designed for both types of dosimeter. (author) [French] L'auteur a employe divers types de cellules comme elements detecteurs des rayons gamma

Comparing of the yield curve of the pediatric X-ray equipment using thermoluminescent dosimeters and cylindrical ionization chamber

International Nuclear Information System (INIS)

Filipov, Danielle; Schelin, Hugo R.; Tilly Junior, Joao G.

2014-01-01

The determination of the yield curve of a radiographic equipment should be realized once a year, or when the unit be serviced. Besides being a requirement of ANVISA, through this test is possible to determine the incident air kerma (at a given point in the center of the beam) - INAK. Based on these concepts, the main objective of this work is the comparison of yield curves of the pediatric X-ray apparatus using two different detectors: one cylindrical ionization chamber and thermoluminescent dosimeters type LiF: Mg, Cu, P, as per protocol RLA / 9/057 IAEA. Then the equation of the yield curve (generated by each detector) was used to determine the INAK of 10 pediatric examinations, performed on this equipment. After the process of calibration of both detectors, they were placed side by side at a focus of the tube equipment for determining the performance of the same curve. Finally, using the curves generated by two detectors, INAK values of the 10 tests were calculated (from the kVp values, and mAs focus-patient of each exams), generating difference values at most 5%. As a conclusion, it can be said that the TLD lithium fluoride doped with Mg, Cu and P and the cylindrical ionization chambers may be used satisfactorily to determine the yield curve, whether as quality control or dosimetry

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-08-15

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

Exposure of treating physician to radiation during prostate brachytherapy using iodine-125 seeds. Dose measurements on both hands with thermoluminescence dosimeters

International Nuclear Information System (INIS)

Schiefer, Hans; Seelentag, Wolf; Plasswilm, Ludwig; Ries, Gerhard; Toggenburg, Friedrich von; Lenggenhager, Cornelius; Schmid, Hans-Peter; Leippold, Thomas; Engeler, Daniel; Prikler, Ladislav; Krusche, Bernd; Roth, Jakob

2009-01-01

Background and purpose: only sparse reports have been made about radiation exposure of the treating physician during prostate seed implantation. Therefore, thermoluminescence dosimeter (TLD) measurements on the index fingers and the backs of both hands were conducted. Material and methods: stranded iodine-125 seeds with a mean apparent activity of 27.4 MBq per seed were used. During application, the treating physician manipulated the loaded needle with the index fingers, partially under fluoroscopic control. Four physicians with varying experience treated 24 patients. The radiation exposure was determined with TLD-100 chips attached to the index fingertips and the backs of hands. Radiation exposure was correlated with the physician's experience. Results: the average brachytherapy duration by the most experienced physician was 19.2 min (standard deviation σ = 1.2 min; novices: 34.8 min [σ = 10.2 min]). The mean activity was 1,703 MBq (σ = 123 MBq), applied with 16.3 needles (σ = 2.5 needles; novices: 1,469 MBq [σ = 229 MBq]; 16.8 needles [σ = 2.3 needles ]). The exposure of the finger of the ''active hand'' and the back of the hand amounted to 1.31 mSv (σ = 0.54 mSv) and 0.61 mSv (σ = 0.23 mSv), respectively (novices: 2.07 mSv [σ = 0.86 mSv] and 1.05 mSv [σ = 0.53 mSv]). Conclusion: if no other radiation exposure needs to be considered, an experienced physician can perform about 400 applications per year without exceeding the limit of 500 mSv/year; for novices, the corresponding figure is about 200. (orig.)

X-ray quality control using TLD-100

International Nuclear Information System (INIS)

Rojas S, D. A.; Garcia V, E.; Azorin N, J.; Gaona, E.

2017-10-01

The use of thermoluminescent dosimeters in the area of medical physics and especially in radiology is of great importance to guarantee the quality of a given study, for this reason the need to verify by means of measurements for quality control in X-rays using thermoluminescent dosimeters of LiF:Mg,Ti was raised. For this, measurements of air Kerma, beam efficiency (reproducibility and linearity) and determination of the hemi-reductive layer were carried out, where previously the dosimeters were used, the graphs of the linear equation were used to obtain the absorbed dose of each dosimeter and thus the results of the absorbed dose calculated analytically against the value estimated by an electronic dosimeter were compared; it was found that the values of the absorbed dose are quantities similar to those stipulated by the electronic dosimeter. These measurements made it possible to verify the quality of the equipment that was used in the comparison. (Author)

Practical use of lithium borate in thermoluminescent dosimetry

International Nuclear Information System (INIS)

Chavaudra, J.; Nguyen, J.; Marinello, G.; Brule, A.M.

1976-01-01

The functional principles of thermoluminescent dosimeters are recalled: heating, apparatus for measuring the emitted light, circulation of nitrogen, reference source. The essential role played by the circulation of nitrogen over the dosimeters which equilibrates the temperature of the photomultiplier, reduces the emission of unwanted light, prevents the combustion of dust or other possible impurities and finally improves the accuracy of the measurements even for high doses, is underlined. Lithium borate is taken as an example and a simple method for finding the optimum working conditions for the heating apparatus of the planchette in the most simple T.L.D. readers and in those where the heating apparatus of the planchette has a pre-heating phase is proposed. The dosimetric properties of lithium borate incorporated in thin teflon discs (type DLB. 0.13 and 0.4) are studied. This shows itself to be very interesting for certain uses because it is a solid dosimeter which does not require annealing between two measurements. The accuracy of the measurements obtained with this material, the stability of the response relative to the delay between radiation and reading (fading), the response relative to the absorbed dose plus the nature and the energy of the rays, are presented with the usual reservations made for this type of dosimetry [fr

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

Energy Technology Data Exchange (ETDEWEB)

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

2007-07-01

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

Thermoluminescence of magnesium doped zirconium oxide (ZrO2:Mg) UV irradiated

International Nuclear Information System (INIS)

Rivera Montalvo, Teodoro; Furetta, Claudio

2008-01-01

Full text: The monitoring of ultraviolet radiation (UVR) different thermoluminescent (TL) materials have been used to measure UVR. UV dosimetry using thermoluminescence phenomena has been suggested in the past by several authors. This technique has an advantage over others methods due to the readout of the samples. Other advantages of these phosphors are their small size, portability, lack of any power requirements, linear response to increasing radiation dose and high sensitivity. Zirconium oxide, recently received full attention in view of their possible use as thermoluminescent dosimeter (TLD), if doped with suitable activators, in radiation dosimetry. In the present investigation thermoluminescent (TL) properties of magnesium doped zirconium oxide (ZrO 2 :Mg) under ultraviolet radiation (UVR) were studied. The ZrO 2 :Mg powder of size 30-40 nm, having mono clinical structure, exhibit a thermoluminescent glow curve with one peak centered at 180 C degrees. The TL response of ZrO 2 :Mg as a function ultraviolet radiation exhibits four maxima centered at 230, 260, 310 and 350 nmn. TL response of ZrO 2 :Mg as a function of spectral irradiance of UV Light was linear in a wide range. Fading and reusability of the phosphor were also studied. The results showed that ZrO 2 :Mg nano powder has the potential to be used as a UV dosemeter in UVR dosimetry. (author)

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)

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

Energy Technology Data Exchange (ETDEWEB)

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

1998-12-31

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

Statistical differences and systematic effect on measurement procedure in thermoluminescent dosimetry of the Iodine-125 brachytherapy seed

International Nuclear Information System (INIS)

Zeituni, Carlos A.; Moura, Eduardo S.; Rostelato, Maria Elisa C.M.; Manzoli, Jose E.; Moura, Joao Augusto; Feher, Anselmo; Karam, Dib

2009-01-01

In order to provide the dosimetry for Iodine-125 seed production in Brazil, Harshaw thermoluminescent dosimeters (TLD-100) will be used. Even if measurements with TLD-100 of the same batch of fabrication are performed, the response will not be the same. As a consequence, they must be measured one by one. These dosimeters are LiF type with a micro-cube (1 mm x 1 mm x 1 mm) shape. Irradiations were performed using Iodine-125 seeds to guarantee the same absorbed dose of 5 Gy in each dosimeter. It has been used a Solid Water Phantom with three concentrically circle with 20 mm, 50 mm and 70 mm diameters. The angle of positions used was 0 deg, 30 deg, 60 deg and 90 deg. Of course there are 2 positions in 0 deg and 90 deg and 4 positions in 30 deg and 60 deg. These complete procedures were carried out five times in order to compare the data and minimize the systematic error. The iodine-125 seed used in the experiment was take off in each measure and put again turning his position 180 deg to guarantee the systematic error was minimized. This paper presents also a little discussion about the statistical difference in the measurement and the calculation procedure to determine the systematic error in these measurements. (author)

Statistical differences and systematic effect on measurement procedure in thermoluminescent dosimetry of the Iodine-125 brachytherapy seed

Energy Technology Data Exchange (ETDEWEB)

Zeituni, Carlos A.; Moura, Eduardo S.; Rostelato, Maria Elisa C.M.; Manzoli, Jose E.; Moura, Joao Augusto; Feher, Anselmo, E-mail: czeituni@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP) Sao Paulo, SP (Brazil); Karam, Dib [Universidade de Sao Paulo (USP Leste), Sao Paulo, SP (Brazil). Escola de Artes, Ciencias e Humanidades

2009-07-01

In order to provide the dosimetry for Iodine-125 seed production in Brazil, Harshaw thermoluminescent dosimeters (TLD-100) will be used. Even if measurements with TLD-100 of the same batch of fabrication are performed, the response will not be the same. As a consequence, they must be measured one by one. These dosimeters are LiF type with a micro-cube (1 mm x 1 mm x 1 mm) shape. Irradiations were performed using Iodine-125 seeds to guarantee the same absorbed dose of 5 Gy in each dosimeter. It has been used a Solid Water Phantom with three concentrically circle with 20 mm, 50 mm and 70 mm diameters. The angle of positions used was 0 deg, 30 deg, 60 deg and 90 deg. Of course there are 2 positions in 0 deg and 90 deg and 4 positions in 30 deg and 60 deg. These complete procedures were carried out five times in order to compare the data and minimize the systematic error. The iodine-125 seed used in the experiment was take off in each measure and put again turning his position 180 deg to guarantee the systematic error was minimized. This paper presents also a little discussion about the statistical difference in the measurement and the calculation procedure to determine the systematic error in these measurements. (author)

Obtention of a thermoluminescent material for dosimetry of ionizing radiation

International Nuclear Information System (INIS)

Gonzalez M, P.R.

1990-01-01

The thermoluminescent dosemeters are small crystals which suffer changes in their structure by the radiation effect, being displaced the electrons toward higher energy levels. On heating the previously irradiated crystals, the electrons come back to their base state emitting light photons. The light quantity emitted is proportional to the received radiation dose. The light quantity emitted is proportional to the received radiation dose. The lithium fluoride is one of the thermoluminescent materials considered as tissue equivalents by having a low effective atomic number (Z ef ). At present, the more used commercial product used of this type is the TLD-100*. In this work the obtained results in the preparation of the lithium fluoride thermoluminescent material are presented. This is activated with magnesium (Mg) and titanium (Ti), which we have labelled as: LiF: Mg, Ti. The results from the tests performed for verifying his thermoluminescent properties are presented too, as powder form as in pellets form. These tests were performed in simultaneous form with TLD-100 samples, which is considered as reference. The LiF: Mg, Ti thermoluminescent material manufactured in the ININ presents similar dosimetric characteristics to those ones of the TLD-100. Therefore being able to replace the imported dosemeters. * (TLD-100 is a commercial trademark registered by Harshaw/Filtrol (US) for LiF: Mg, Ti Tl dosemeters) (Author)

Thermoluminescence response of Ge-, Al- and Nd- doped optical fibers by 6 MeV - electron and 6 MeV - photon irradiations

International Nuclear Information System (INIS)

Hossain, I.; Moburak, A. A.; Saeed, M.A.; Wagiran, H.; Hida, N.; Yaakob, H.N.

2015-01-01

In this paper, we report the prediction of thermoluminescence responses of Neodymium-doped SiO 2 optical fibre with various dose ranges from 0.5 Gy to 4.0 Gy by 6 MeV - electron irradiations without requirement for experimental measurements. A technique has been developed to calculate prediction of 6 MeV - electron response of Neodymium-doped SiO 2 optical fibre by observing the measured TL response of 6 MV - photon and the ratio of known measured photon/electron yield ratio distribution for Ge-doped, Al-doped optical fibre and standard TLD 100 dosimeter. The samples were kept in gelatin capsule an irradiated with 6 MV - photon at the dose range from 0.5 Gy to 4.0 Gy. Siemens model Primus 3368 linear accelerator located at Hospital Sultan Ismail, Johor Bahru has been used to deliver the photon beam to the samples. We found the average response ratio of 6 MV - photon and 6 MeV - electron in Ge-doped, Al-doped optical fibre and standard TLD-100 dosimeter are 0.83(3). Observing the measured value of 6 MV - photon irradiation this average ratio is useful to find the prediction of thermoluminescence responses by 6 MeV - electron irradiation of Neodymium-doped SiO 2 optical fibre by the requirement for experimental measurements with various dose ranges from 0.5 Gy to 4.0 Gy by 6 MV - photon irradiations.

The application of thermoluminescent dosimeters to the measurement of thermal neutron distributions in bulk media

International Nuclear Information System (INIS)

Bubb, I.F.; Tang, J.C.N.

1981-01-01

The work described was designed to investigate the suitability of measuring neutron flux distributions in bulk media using neutron sensitive thermoluminescent dosimeters, with the initial interest being in wet coal matrices. The phosphors used were 6 LiF and 7 LiF 3.2mmx3.2mmx0.9mm chips. As 7 LiF is sensitive to gamma rays only it was used to correct for the gamma-ray response of 6 LiF

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

International Nuclear Information System (INIS)

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

2000-01-01

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

Dose measurements in intraoral radiography using thermoluminescent dosimeters

Science.gov (United States)

Azorín, C.; Azorín, J.; Aguirre, F.; Rivera, T.

2015-01-01

The use of X-ray in medicine demands to expose the patient and the professional to the lowest radiation doses available in agreement with ALARA philosophy. The reference level for intraoral dental radiography is 7 mGy and, in Mexico, a number of examinations of this type are performed annually. It is considered that approximately 25% of all the X-rays examinations carried out in our country correspond to intraoral radiographies. In other hand, most of the intraoral X-ray equipment correspond to conventional radiological systems using film, which are developed as much manual as automatically. In this work the results of determining the doses received by the patients in intraoral radiological examinations made with different radiological systems using LiF:Mg,Cu,P+PTFE thermoluminescent dosimeters are presented. In some conventional radiological systems using film, when films are developed manual or automatically, incident kerma up to 10.61 ± 0.74 mGv were determined. These values exceed that reference level suggested by the IAEA and in the Mexican standards for intraoral examinations.

Dose measurements in intraoral radiography using thermoluminescent dosimeters

International Nuclear Information System (INIS)

Azorín, C; Rivera, T; Azorín, J; Aguirre, F

2015-01-01

The use of X-ray in medicine demands to expose the patient and the professional to the lowest radiation doses available in agreement with ALARA philosophy. The reference level for intraoral dental radiography is 7 mGy and, in Mexico, a number of examinations of this type are performed annually. It is considered that approximately 25% of all the X-rays examinations carried out in our country correspond to intraoral radiographies. In other hand, most of the intraoral X-ray equipment correspond to conventional radiological systems using film, which are developed as much manual as automatically. In this work the results of determining the doses received by the patients in intraoral radiological examinations made with different radiological systems using LiF:Mg,Cu,P+PTFE thermoluminescent dosimeters are presented. In some conventional radiological systems using film, when films are developed manual or automatically, incident kerma up to 10.61 ± 0.74 mGv were determined. These values exceed that reference level suggested by the IAEA and in the Mexican standards for intraoral examinations

Dosimetric comparison on tissue interfaces with TLD dosimeters, L-alanine, EDR2 films and Penelope simulation for a Co-60 source and linear accelerator in radiotherapy

International Nuclear Information System (INIS)

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

2015-10-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Estrada E, D

2002-07-01

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

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

International Nuclear Information System (INIS)

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

2002-01-01

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

A computerized glow curve analysis (GCA) method for WinREMS thermoluminescent dosimeter data using MATLAB

International Nuclear Information System (INIS)

Harvey, John A.; Rodrigues, Miesher L.; Kearfott, Kimberlee J.

2011-01-01

A computerized glow curve analysis (GCA) program for handling of thermoluminescence data originating from WinREMS is presented. The MATLAB program fits the glow peaks using the first-order kinetics model. Tested materials are LiF:Mg,Ti, CaF 2 :Dy, CaF 2 :Tm, CaF 2 :Mn, LiF:Mg,Cu,P, and CaSO 4 :Dy, with most having an average figure of merit (FOM) of 1.3% or less, with CaSO 4 :Dy 2.2% or less. Output is a list of fit parameters, peak areas, and graphs for each fit, evaluating each glow curve in 1.5 s or less. - Highlights: → Robust algorithm for performing thermoluminescent dosimeter glow curve analysis. → Written in MATLAB so readily implemented on variety of computers. → Usage of figure of merit demonstrated for six different materials.

Thermoluminescence dosimetry in quality imaging in CR mammography systems

Energy Technology Data Exchange (ETDEWEB)

Gaona, E.; Franco E, J.G. [UAM-Xochimilco, 04960 Mexico D.F. (Mexico); Azorin N, J. [UAM-Iztapalapa, 09340 Mexico D.F. (Mexico); Diaz G, J.A.I. [CICATA, Unidad Legaria, Av. Legaria 694, 11599 mexico D.F. (Mexico); Arreola, M. [Department of Radiology, Shands Hospital at UF, PO Box 100374, Gainesville, FL 32610-0374 (United States)

2006-07-01

The aim of this work is to estimate the average glandular dose with Thermoluminescence Dosimetry (TLD) and comparison with quality imaging in CR mammography. For measuring dose, FDA and 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 CR mammography 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 fluoro halide. 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 that overcomes 3.0 mGy and it doesn't improve the image quality and dose to the breast will be excessive. 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. (Author)

Thermoluminescence dosimetry in quality imaging in CR mammography systems

International Nuclear Information System (INIS)

Gaona, E.; Franco E, J.G.; Azorin N, J.; Diaz G, J.A.I.; Arreola, M.

2006-01-01

The aim of this work is to estimate the average glandular dose with Thermoluminescence Dosimetry (TLD) and comparison with quality imaging in CR mammography. For measuring dose, FDA and 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 CR mammography 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 fluoro halide. 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 that overcomes 3.0 mGy and it doesn't improve the image quality and dose to the breast will be excessive. 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. (Author)

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

International Nuclear Information System (INIS)

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

2014-08-01

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

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)

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

Science.gov (United States)

Lee, YoungJu; Won, Yuho; Kang, Kidoo

2015-04-01

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

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

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2007-07-01

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

Thermoluminescence dosimetry materials: properties and uses

International Nuclear Information System (INIS)

McKeever, S.W.S.; Moscovitch, M.; Townsend, P.D.

1995-01-01

This book selects a range of the most popular thermoluminescence dosemeter (TLD) materials in use today and provides a critical account of their thermoluminescence (TL) and dosimetric properties. The information provided includes in-depth discussions of TL mechanisms, including an account of luminescence properties, and relevant information regarding dosimetric characteristics. The book is intended for those involved in TLD materials research, and for technicians and workers involved in the practical application of these materials in TL dosimetry. The advent of modern spectroscopic methods for measuring TL emission spectra (the so-called ''3-D'' presentation) seemed to the authors to be an invitation to compile such spectra for all the major TLD materials. Further consideration led to an expansion of the initial idea to include a compilation of dosimetric properties. One intention is to provide a synopsis of the TL and dosimetric properties of the most widely used TLD materials currently available and to form a link between the solid state defect properties of these materials and their actual dosimetric properties. A second intention is to provide a solid framework from which future studies of TLD materials could be launched. Too often in the past research into TLD materials has been haphazard, to say the least. By illustrating the links between solid state physics and the radiation dosimetry properties of these materials the book points to the future and to the pressing need for enhanced research on TLD materials. (Author)

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

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

Science.gov (United States)

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

2014-01-01

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

Ionizing radiation source detection by personal TLD

International Nuclear Information System (INIS)

Marinkovic, O.; Mirkov, Z.

2002-01-01

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

Numerical analysis of thermoluminescence glow curves; Analisis numerico de las cruvas de termoluminiscencia

Energy Technology Data Exchange (ETDEWEB)

Gomez Ros, J M; Delgado, A

1989-07-01

This report presents a method for the numerical analysis of complex thermoluminescence glow curves resolving the individual glow peak components. The method employs first order kinetics analytical expressions and is based In a Marquart-Levenberg minimization procedure. A simplified version of this method for thermoluminescence dosimetry (TLD) is also described and specifically developed to operate whit Lithium Fluoride TLD-100. (Author). 36 refs.

Evaluation of environmental monitoring thermoluminescent dosimeter locations

International Nuclear Information System (INIS)

Kinnison, R.

1992-12-01

Geostatistics, particularly kriging, has been used to assess the adequacy of the existing NTS thermoluminescent dosimeter network for determination of environmental exposure levels. (Kriging is a linear estimation method that results in contour plots of both the pattern of the estimated gamma radiation over the area of measurements and also of the standard deviations of the estimated exposure levels.) Even though the network was not designed as an environmental monitoring network, ft adequately serves this function in the region of Pahute and Rainier Mesas.. The Yucca Flat network is adequate only if a reasonable definition of environmental exposure levels is required; R is not adequate for environmental monitoring in Yucca Flat if a coefficient of variation of 10 percent or less is chosen as the criterion for network design. A revision of the Yucca Flat network design should be based on a square grid pattern with nodes 5000 feet (about one mile) apart, if a 10 percent coefficient of variation criterion is adopted. There were insufficient data for southern and western sections of the NTS to perform the geostatistical analysis. A very significant finding was that a single network design cannot be used for the entire NTS, because different areas have different variograms. Before any design can be finalized, the NTS management must specify the exposure unit area and coefficient of variation that are to be used as design criteria

Area monitoring dosimeter program for the Pacific Northwest National Laboratory: Results for CY 1997

International Nuclear Information System (INIS)

Bivins, S.R.; Stoetzel, G.A.

1998-07-01

In January 1993, Pacific Northwest National Laboratory (PNNL) established an area monitoring dosimeter program in accordance with Article 514 of the US Department of Energy (DOE) Radiological Control Manual (RCM). The purpose of the program was to minimize the number of areas requiring issuance of personnel dosimeters and to demonstrate that doses outside Radiological Buffer Areas are negligible. In accordance with 10 CFR Part 835.402 (a) (1)--(3) and Article 511.1 of the RCM, personnel dosimetry shall be provided to (1) radiological workers who are likely to receive at least 100 mrem annually, and (2) declared pregnant workers, minors, and members of the public who are likely to receive at least 50 mrem annually. Program results for calendar years (CY) 1993--1996 confirmed that personnel dosimetry was not needed for individuals located in areas monitored by the program. A total of 93 area thermoluminescent dosimeters (TLDs) were placed in PNNL facilities during CY 1997. The TLDs were exchanged and analyzed quarterly. All routine area monitoring TLD results were less than 50 mrem annually after correcting for worker occupancy. The results support the conclusions that personnel dosimeters are not necessary for staff, declared pregnant workers, minors, or members of the public in these monitored areas

Area Monitoring Dosimeter Program for the Pacific Northwest National Laboratory: Results for CY 1998

International Nuclear Information System (INIS)

GA Stoetzel; SR Bivins

1999-01-01

In January 1993, Pacific Northwest National Laboratory (PNNL) established an area monitoring dosimeter program in accordance with Article 514 of the Department of Energy (DOE) Radiological Control Manual (RCM). The purpose of the program was to minimize the number of areas requiring issuance of personnel dosimeters and to demonstrate that doses outside Radiological Buffer Areas are negligible. In accordance with 10 CFR Part 835.402 (a)(1)-(4) and Article 511.1 of the RCM, personnel dosimetry shall be provided to (1) radiological workers who are likely to receive at least 100 mrem annually and (2) declared pregnant workers, minors, and members of the public who are likely to receive at least 50 mrem annually. Program results for calendar years 1993-1997 confirmed that personnel dosimetry was not needed for individuals located in areas monitored by the program. A total of 97 area thermoluminescent dosimeters (TLDs) were placed in PNNL facilities during calendar year 1998. The TLDs were exchanged and analyzed quarterly. All routine area monitoring TLD results were less than 50 mrem annually after correcting for worker occupancy. The results support the conclusion that personnel dosimeters are not necessary for staff, declared pregnant workers, minors, or members of the public in these monitored areas

As the thermoluminescent dosimetry can help in the quality control in radiotherapy

International Nuclear Information System (INIS)

Araujo, Anna Maria Campos de; Marin, Alfredo Viamonte; Viegas, Claudio C.B.; Souza, Roberto Salomon de; Alves, Victor Gabriel Leandro

2011-01-01

According to the international (International Atomic Energy Agency) and national (Agencia Nacional de Vigilancia Sanitaria- ANVISA) rules, the irradiators of any radiotherapy department should be periodical/y checked through a quality control external audit. In Brazil, where we have about 300 radiotherapy equipment, is very difficult to perform these audits on site with a acceptable frequency. For this reason, the Quality Service on Ionizing Radiations from the National Cancer Institute-INCA/Rio de Janeiro, developed and implemented postal systems to evaluate the main parameters of the radiotherapeutic equipment (Co-60, linear accelerators and high dose rate brachytherapy). All the postal systems developed are based on thermoluminescent dosimeters. The aim of this paper is to share the INCA experience in the use of TLD for dose evaluation and quality control measurements. Following the same philosophy, INCA developed also a postal system to evaluate the doses in mammography, since Brazil has 4000 equipment and performs about 8 millions of mammograms per year. A new experience is studying the OSL dosimeters to be used also for dose evaluation, including for in vivo dosimetry. (author)

PTFE Additive and Re-annealing Effect on Thermoluminescence Response of CaSO4:Dy Derived from Co-precipitation Method

Science.gov (United States)

Nuraeni, Nunung; Dwi Septianto, Ricky; Iskandar, Ferry; Haryanto, Freddy; Waris, Abdul; Hiswara, Eri

2017-07-01

Effect of re-annealing treatment in thermoluminescence response of thermoluminescent dosimeter (TLD) CaSO4:Dy and CaSO4:Dy with PTFE (Polytetrafluoroethylene) addition was investigated. CaSO4:Dy was prepared by a co-precipitation method. The PTFE was added before re-annealing treatment which the mass ratio of CaSO4:Dy and PTFE was fixed to 2:3. The re-annealing treatments of the samples were done at temperature 700 °C for 1 hr. The obtained samples were characterized using a Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) to observe the molecule bonding in sample and crystal properties, respectively. From the experimental results, it was observed that the thermoluminescence intensity of CaSO4:Dy, CaSO4:Dy re-annealed at 700 °C, and CaSO4:Dy + PTFE re-annealed at 700 °C are 57.03, 75.15, and 1191.11 nC, respectively. The intensity of 700 °C-re-annealed CaSO4:Dy increased significantly after PTFE addition.

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

International Nuclear Information System (INIS)

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

2014-08-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-08-15

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

Application of numerical analysis methods to thermoluminescence dosimetry

International Nuclear Information System (INIS)

Gomez Ros, J. M.; Delgado, A.

1989-01-01

This report presents the application of numerical methods to thermoluminescence dosimetry (TLD), showing the advantages obtained over conventional evaluation systems. Different configurations of the analysis method are presented to operate in specific dosimetric applications of TLD, such as environmental monitoring and mailed dosimetry systems for quality assurance in radiotherapy facilities. (Author) 10 refs

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

International Nuclear Information System (INIS)

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

2017-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-05-15

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

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

Determination of the TLD-100 physical parameters

International Nuclear Information System (INIS)

Paucar J, J.; Picon C, C.

1998-01-01

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

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)

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

Science.gov (United States)

Eakins, Jonathan

2009-02-01

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

Clinical use of LiF:Mg,Cu,P: Critical evaluation of an ultrasensitive material for thermoluminescence dosimetry

International Nuclear Information System (INIS)

Duggan, Lisa

2002-01-01

Radiation dosimetry is an essential part of optimization in medical exposures. However there are medical procedures that are particularly challenging for existing dosimetric techniques: neonatal radiography (low dose), mammography (low energy), cardiac catheterization (moving radiation fields), and brachytherapy using implanted radionuclides (steep dose gradients). Hence, the objectives of this thesis were to study the dosimetric characteristics of ultrasensitive LiF:Mg,Cu,P thermoluminescence dosimeters (TLDs) in radiation beams typical for both diagnostics and therapy, and develop procedures to implement this dosimeter into clinical practice for those selected scenarios. GR-200 (SDDML, China) and MCP-N (TLD Poland) TLDs were compared to other TLD materials (LiF:Mg,Ti, Al 2 O 3 :C) and tested for reproducibility, dose response (1 μGy to 500 Gy), photon energy response (10 keV to 18 MVp), light sensitivity (240-800 nm), long-term stability (6 months) using different annealing cycles and glow curve deconvolution. A miniaturized TLD form (MCP-Np) was developed by TLD Poland for the present investigations. Detection limit of GR-200 and MCP-Np was found to be less than 1 and 8 μGy, respectively, with dose response linear up to 18 Gy. To obtain adequate detection limits and precision, accurate temperature calibration of heating cycles and a dual-anneal technique with dose history monitoring was performed. Energy response was similar for both materials within 5% and essentially uniform except for a minimum of 0.82 at 185 keV. LiF:Mg,Cu,P proved to be more suitable than LiF:Mg,Ti for dosimetry in low dose medical applications particularly when kilovoltage photons are to be used. The high sensitivity and resulting scope for miniaturization provided the opportunity to perform unique in vivo measurements within brachytherapy implants and for mammography

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

Evaluation of the uncertainties in the TLD radiosurgery postal dose system

Science.gov (United States)

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

2018-03-01

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

Recent research into thermoluminescent dosimetry

Energy Technology Data Exchange (ETDEWEB)

Nakajima, T [National Inst. of Radiological Sciences, Chiba (Japan)

1979-04-01

The trend of basic research in thermoluminescent dosimetry (TLD), the results, and developing fields in which it can be applied are reported. This trend is outlined from the viewpoint fields of application, a new trend in TLD readers, the conditions of development of new photogenic substances, and research in the radiation characteristics of photogenic substances (radiosensitivity to particle rays and ultraviolet rays, dose rate dependence, temperature dependence at irradiation, and ..gamma.. ray energy dependence). Utilization of TLD in the medical field for measurement of environmental radiation and as a monitor for workers exposed to radiation is discussed. An international comparison of dose was necessary in order to prove its universal validity.

The study of new calibration features in the Harshaw TLD system

International Nuclear Information System (INIS)

Luo, L.Z.

2005-01-01

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

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

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

Energy Technology Data Exchange (ETDEWEB)

Sagastibelza Chivite, F

1980-07-01

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

Type tests to the automatic thermoluminescent dosimetry system acquired by the CPHR for personal dosimetry

International Nuclear Information System (INIS)

Molina P, D.; Pernas S, R.; Martinez G, A.

2006-01-01

The CPHR individual monitoring service acquired an automatic RADOS TLD system to improve its capacities to satisfy the increasing needs of their national customers. The TLD system consists of: two automatic TLD reader, model DOSACUS, a TLD irradiator and personal dosimeters card including slide and holders. The dosimeters were composed by this personal dosimeters card and LiF:Mg,Cu,P (model GR-200) detectors. These readers provide to detectors a constant temperature readout cycle using hot nitrogen gas. In order to evaluate the performance characteristics of the system, different performance tests recommended by the IEC 1066 standard were carried out. Important dosimetric characteristics evaluated were batch homogeneity, reproducibility, detection threshold, energy dependence, residual signal and fading. The results of the tests showed good performance characteristics of the system. (Author)

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

International Nuclear Information System (INIS)

Miller, Thomas Martin; Celik, Cihangir; Isbell, Kimberly McMahan; Lee, Yi-kang; Gagnier, Emmanuel; Authier, Nicolas; Piot, Jerome; Jacquet, Xavier; Rousseau, Guillaume; Reynolds, Kevin H.

2016-01-01

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

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

International Nuclear Information System (INIS)

Miller, Thomas Martin; Celik, Cihangir; McMahan, Kimberly L.; Lee, Yi-kang; Gagnier, Emmanuel; Authier, Nicolas

2016-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-09-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-09-01

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

Estimation of eye absorbed doses in head & neck radiotherapy practices using thermoluminescent detectors

Directory of Open Access Journals (Sweden)

Gh Bagheri

2011-09-01

Full Text Available  Determination of eye absorbed dose during head & neck radiotherapy is essential to estimate the risk of cataract. Dose measurements were made in 20 head & neck cancer patients undergoing 60Co radiotherapy using LiF(MCP thermoluminescent dosimeters. Head & neck cancer radiotherapy was delivered by fields using SAD & SSD techniques. For each patient, 3 TLD chips were placed on each eye. Head & neck dose was about 700-6000 cGy in 8-28 equal fractions. The range of eye dose is estimated to be (3.49-639.1 mGy with a mean of maximum dose (98.114 mGy, which is about 3 % of head & neck dose. Maximum eye dose was observed for distsnces of about 3 cm from edge of the field to eye.

The application of artificial neural networks to TLD dose algorithm

International Nuclear Information System (INIS)

Moscovitch, M.

1997-01-01

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

Determination of trapping parameters of dosimetric thermoluminescent glow peak of lithium triborate (LiB{sub 3}O{sub 5}) activated by aluminum

Energy Technology Data Exchange (ETDEWEB)

Kafadar, V. Emir [University of Gaziantep, Department of Engineering Physics, 27310 Gaziantep (Turkey); Yazici, A. Necmeddin, E-mail: yazici@gantep.edu.t [University of Gaziantep, Department of Engineering Physics, 27310 Gaziantep (Turkey); Yildirim, R. Gueler [University of Gaziantep, Department of Engineering Physics, 27310 Gaziantep (Turkey)

2009-07-15

Lithium triborate (LBO) is a newly developed ideal nonlinear optical (NLO) crystal used in laser weapon, welder, radar, tracker, surgery, communication, etc. The effective atomic number (Z{sub eff}=7.3) makes it a tissue equivalent material and this encourages studies on its thermoluminescence (TL) properties for a radiation dosimetry. The previous studies have shown that Al-doped LiB{sub 3}O{sub 5} is a promising thermoluminescent dosimetric (TLD) material for dosimetric purposes and continuous and systematic investigations to improve its quality to get ones suited for dosimeter applications are worthy. In the given study, the additive dose (AD), initial rise with partial cleaning (IR), variable heating rate (VHR), peak shape (PS), three-points method (TPM) and computerized glow deconvolution (CGCD) methods were used to determine the kinetic parameters, namely the order of kinetics (b), activation energy (E{sub a}) and the frequency factor (s) associated with the dosimetric thermoluminescent glow peak (P3) of Al-doped LiB{sub 3}O{sub 5} after different dose levels with beta-irradiation.

N.R.P.B.'s new record-keeping service and thermoluminescent dosemeter

International Nuclear Information System (INIS)

Dennis, J.A.; Marshall, T.O.; Shaw, K.B.; Kendall, G.M.

1977-01-01

With the approval of the Health and Safety Executive the National Radiological Protection Board is introducing a radiation dose record keeping service in association with a thermoluminescent dosimeter. This service will relieve employers of the responsibility for maintaining and keeping dose records. Both the record keeping and dosimeter systems are described, including the documents which will be produced for employers. The thermoluminescent dosimeter is more accurate and less sensitive to environmental factors than the film dosimeter, which it replaces. It also reduces the consumption of materials and, with automated processing, is labour saving. (author)

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-11-07

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

Thermoluminescence of zirconium oxide nanostructured to mammography X-ray beams

International Nuclear Information System (INIS)

Palacios, L.L.; Rivera, T.; Roman, J.; Azorín, J.; Gaona, E.

2012-01-01

In the present work thermoluminescent (TL) response of zirconium oxide (ZrO 2 ) nanostructured induced by mammography X-ray radiation was investigated. Measurements were made of the response per unit air kerma of ZrO 2 with mammography equipment parameters (semiautomatic exposure control, 24 kVp and 108 mAs). The calibration curves were obtained by simultaneously irradiating ZrO 2 samples and ion chamber. Samples of ZrO 2 showed a linear response as a function of entrance skin air kerma. The observed results in TL properties suggest that ZrO 2 nanostructured could be considered as an effective material for X-ray beams dosimetry if appropriate calibration procedures are performed. - Highlights: ► X-ray low energy thermoluminescent of ZrO 2 dosimeter is developed. ► Air kerma measurements were made by thermoluminescent dosimeter ZrO 2 using mammography equipment parameters. ► Entrance surface skin doses were made using thermoluminescent dosimeter of ZrO 2 to X-ray beam quality control.

Type tests to the automatic system of thermoluminescent dosimetry acquired by the CPHR for personnel dosimetry

International Nuclear Information System (INIS)

Molina P, D.; Pernas S, R.

2005-01-01

The CPHR individual monitoring service acquired an automatic RADOS TLD system to improve its capacities to satisfy the increasing needs of their national customers. The TLD system consists of: two automatic TLD reader, model DOSACUS, a TLD irradiator and personal dosimeters card including slide and holders. The dosimeters were composed by this personal dosimeters card and LiF: Mg,Cu,P (model GR-200) detectors. These readers provide to detectors a constant temperature readout cycle using hot nitrogen gas. In order to evaluate the performance characteristics of the system, different performance tests recommended by the IEC 1066 standard were carried out. Important dosimetric characteristics evaluated were batch homogeneity, reproducibility, detection threshold, energy dependence, residual signal and fading. The results of the tests showed good performance characteristics of the system. (Author)

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

Calibration procedure for thermoluminescent dosemeters in water absorbed doses for Iridium-192 high dose rate sources

International Nuclear Information System (INIS)

Reyes Cac, Franky Eduardo

2004-10-01

Thermoluminescent dosimeters are used in brachytherapy services quality assurance programs, with the aim of guaranteeing the correct radiation dose supplied to cancer patients, as well as with the purpose of evaluating new clinical procedures. This work describes a methodology for thermoluminescent dosimeters calibration in terms of absorbed dose to water for 192 Ir high dose rate sources. The reference dose used is measured with an ionization chamber previously calibrated for 192 Ir energy quality, applying the methodology proposed by Toelli. This methodology aims to standardizing the procedure, in a similar form to that used for external radiotherapy. The work evolves the adaptation of the TRS-277 Code of the International Atomic Energy Agency, for small and big cavities, through the introduction for non-uniform experimental factor, for the absorbed dose in the neighborhood of small brachytherapy sources. In order to simulate a water medium around the source during the experimental work, an acrylic phantom was used. It guarantees the reproducibility of the ionization chamber and the thermoluminescent dosimeter's location in relation to the radiation source. The values obtained with the ionization chamber and the thermoluminescent dosimeters, exposed to a 192 Ir high dose rate source, were compared and correction factors for different source-detector distances were determined for the thermoluminescent dosimeters. A numeric function was generated relating the correction factors and the source-detector distance. These correction factors are in fact the thermoluminescent dosimeter calibration factors for the 192 Ir source considered. As a possible application of this calibration methodology for thermoluminescent dosimeters, a practical range of source-detector distances is proposed for quality control of 192 Ir high dose rate sources. (author)

A microcomputer controlled thermoluminescence dosimetry system

International Nuclear Information System (INIS)

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

1980-01-01

Using a microcomputer, an automatic thermoluminescence dosimetry system for personal dosimetry and thermoluminescence detector (TLD) research was developed. Process automation, statistical computation and dose calculation are provided by this microcomputer. Recording of measurement data, as well as dose record keeping for radiological workers is carried out with floppy disk. The microcomputer also provides a human/system interface by means of a video display and a printer. The main features of this dosimetry system are its low cost, high degree of flexibility, high degree of automation and the feasibility for use in routine dosimetry as well as in TLD research. The system is in use for personal dosimetry, environmental dosimetry and for TL-research work. Because of its modular set-up several components of the system are in use for other applications, too. The system seems suited for medium sized health physics groups. (author)

Thermoluminescence, a universal tool for dosimetry

International Nuclear Information System (INIS)

Barthe, J.

1999-01-01

Radio-thermoluminescence is a transient light emission occurring when certain substances, which have been exposed to ionizing radiation, are heated. Under some conditions the quantity of emitted light is proportional to the absorbed dose. This linearity allows thermoluminescence to be used in various fields such as dosimetry, geology and age determination. Dosimeters based on thermoluminescence are passive, they do not require a source of energy and they can sustain high temperatures and high levels of irradiation. Thermoluminescence has been applied for determining the dose absorbed by meteorites and lunar rocks

Estimation of uncertainty in TLD calibration

International Nuclear Information System (INIS)

Hasabelrasoul, H. A.

2013-07-01

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

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

International Nuclear Information System (INIS)

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

2014-01-01

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

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

International Nuclear Information System (INIS)

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

1996-01-01

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

Environmental radiation measurements using TLD in and around AERE, Dhaka

International Nuclear Information System (INIS)

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

1986-01-01

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

Thermoluminescent response of LiF before variation of the heating rate

International Nuclear Information System (INIS)

Barrios, R.; Avila, O.

2003-01-01

Comparisons of glow curves of lithium fluoride dosemeters TLD-100 measured to two heating rates with the purpose of quantifying the change in the temperature of the peaks 5 and 7 for the thermoluminescent reader equipment Harshaw 4000 of the thermoluminescence laboratory of the ININ were carried out. (Author)

Personal exposure control using TLD

International Nuclear Information System (INIS)

Ishiguro, Hideharu; Takeda, Shinso

1979-01-01

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

High-energy neutron dosimetry at the Clinton P. Anderson Meson Physics Facility

International Nuclear Information System (INIS)

Mallett, M.W.; Vasilik, D.G.; Littlejohn, G.J.; Cortez, J.R.

1990-01-01

Neutron energy spectrum measurements performed at the Clinton P. Anderson Meson Physics Facility indicated potential areas for high energy neutron exposure to personnel. The low sensitivity of the Los Alamos thermoluminescent dosimeter (TLD) to high energy neutrons warranted issuing a NTA dosimeter in addition to the TLD badge to employees entering these areas. The dosimeter consists of a plastic holder surrounding NTA film that has been desiccated and sealed in a dry nitrogen environment. A study of the fading of latent images in NTA film demonstrated the success of this packaging method to control the phenomenon. The Los Alamos NTA dosimeter is characterized and the fading study discussed. 10 refs., 4 figs., 2 tabs

Thermoluminescence of zirconium oxide nanostructured to mammography X-ray beams

Energy Technology Data Exchange (ETDEWEB)

Palacios, L.L. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-Legaria, IPN. Av. Legaria 694, 11500 Mexico D.F. (Mexico); Rivera, T., E-mail: trivera@ipn.mx [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-Legaria, IPN. Av. Legaria 694, 11500 Mexico D.F. (Mexico); Roman, J. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-Legaria, IPN. Av. Legaria 694, 11500 Mexico D.F. (Mexico); Azorin, J. [Universidad Autonoma Metropolitana-Iztapalapa. Av. San Rafael Atlixco 187, 09340 Mexico D.F. (Mexico); Gaona, E. [Universidad Autonoma Metropolitana-Xochimilco. Calz. Del Hueso 1100, 04960 Mexico D.F. (Mexico)

2012-07-15

In the present work thermoluminescent (TL) response of zirconium oxide (ZrO{sub 2}) nanostructured induced by mammography X-ray radiation was investigated. Measurements were made of the response per unit air kerma of ZrO{sub 2} with mammography equipment parameters (semiautomatic exposure control, 24 kVp and 108 mAs). The calibration curves were obtained by simultaneously irradiating ZrO{sub 2} samples and ion chamber. Samples of ZrO{sub 2} showed a linear response as a function of entrance skin air kerma. The observed results in TL properties suggest that ZrO{sub 2} nanostructured could be considered as an effective material for X-ray beams dosimetry if appropriate calibration procedures are performed. - Highlights: Black-Right-Pointing-Pointer X-ray low energy thermoluminescent of ZrO{sub 2} dosimeter is developed. Black-Right-Pointing-Pointer Air kerma measurements were made by thermoluminescent dosimeter ZrO{sub 2} using mammography equipment parameters. Black-Right-Pointing-Pointer Entrance surface skin doses were made using thermoluminescent dosimeter of ZrO{sub 2} to X-ray beam quality control.

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

International Nuclear Information System (INIS)

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

1985-09-01

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

Study of analysis techniques of thermoluminescent dosimeters response

International Nuclear Information System (INIS)

Castro, Walber Amorim

2002-01-01

The Personal Monitoring Service of the Centro Regional de Ciencias Nucleares uses in its dosemeter the TLD 700 material . The TLD's analysis is carried out using a Harshaw-Bicron model 6600 automatic reading system. This system uses dry air instead of the traditional gaseous nitrogen. This innovation brought advantages to the service but introduced uncertainties in the reference of the detectors; one of these was observed for doses below 0,5 mSv. In this work different techniques of analysis of the TLD response were investigated and compared, involving dose values in this interval. These techniques include thermal pre-treatment, and different kinds of the glow curves analysis methods were investigated. Obtained results showed the necessity of developing a specific software that permits the automatic background subtraction for the glow curves for each dosemeter . This software was developed and it bean tested. Preliminary results showed the software increase the response reproducibility. (author)

Performance of thermoluminescent materials for high dose dosimetry

International Nuclear Information System (INIS)

Texeira, Maria I.; Cecatti, Sonia G.P.; Caldas, Linda V.E.

2008-01-01

Cases involving high-doses of ionizing radiation are becoming increasingly common.The objective of this work was to characterize thermoluminescent materials for the dosimetry of workers exposed to high doses. Samples of TLD-200, TLD-400 and TLD-800 pellets from Thermo Electron Corporation were studied in gamma high-doses. Dose-response curves were obtained for doses between 100 mGy and 100 Gy. The reproducibility, the lower detection limits and dose-response curves were obtained for all three materials. The different kinds of detectors show usefulness for dosimetry of workers exposed accidentally to high doses. (author)

Thermoluminescent response of Y{sub 2}O{sub 3}:Ce,Eu irradiated with X-rays; Respuesta termoluminiscente del Y{sub 2}O{sub 3}:Ce,Eu irradiado con rayos X

Energy Technology Data Exchange (ETDEWEB)

Sanchez J, F. del R. [Universidad APEC, Escuela de Ingenieria, Apdo. Postal No. 2867, 10107 Santo Domingo (Dominican Republic); Sosa A, M. A., E-mail: sanchezjaquez@gmail.com [Universidad de Guanajuato, Division de Ciencias e Ingenierias, Campus Leon, 37670 Leon, Guanajuato (Mexico)

2017-10-15

The thermoluminescent response of various materials has been studied when irradiated with X-rays, and the parameters that characterize the order of the kinetics of the material, depth of traps and frequency have been determined. The objective of this project was to characterize the thermoluminescent response of dosimeters based on yttrium oxide (Y{sub 2}O{sub 3}) irradiated with X-rays. To do this, the thermoluminescent response of the Y{sub 2}O{sub 3}:Ce,Eu dosimeter was measured and exposed to an X-ray radiation field; five levels of radiation were used: in the first, a potential of 53.5 kv was used and a working load of 5.6 m As, in the second: 70.0 kv, 12.5 m As; in the third: 81.0 kv, 20.0 m As; in the fourth: 109 kv, 32 m As, in the fifth: 121 kv, 80.0 m As, applying an exposure range between 17.7 and 40 R. The irradiation was performed exposing the sample at 104 cm from the focus of the X-ray tube. To obtain the readings of the thermoluminescent response, a Harshaw TLD 3500 reader was used. The data captured by the reader was processed using the WinREMS software. The deletion protocol was as follows: the dosimeters already read were placed, one hour in the Terlab MA12D muffle at a temperature of (400 ± 1) degrees centigrade, the dosimeters were removed and left at room temperature of 20 degrees centigrade for 20 minutes. Then they were placed in the Binder high temperature oven ED23 at 100 ± 1 centigrade degrees for 2 hours. The brightness curves were de convolved using the WebPlotDigitizer v 3.8 software and the individual peaks of the brightness curves were obtained. We found that: the synthesized materials presented a good thermoluminescent response when irradiated with X-rays. However, only one of the dosimeters, of Yttrium oxide doped with 0.5% Cerium, showed a relatively linear response in the applied dose range. The analysis made to the brightness curve of the Yttrium oxide doped with Cerium at 0.5%, applying the method of the three points for the

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

Energy Technology Data Exchange (ETDEWEB)

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

2010-07-01

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

Thermoluminescence of LiF: Mg, Ti between 77 and 315 K

International Nuclear Information System (INIS)

Rosa, L.A.R. da.

1989-01-01

A special thermoluminescent system was developed. It is able to operate right from liquid nitrogen temperature and also permits the determination of the sample thermoluminescent emission spectrum. Using this system, the thermoluminescence displayed by 77 K irradiated LiF:Mg,Ti (TLD-100), from the irradiation temperature to 315 K, was studied. In this temperature range seven glow peaks, at 139, 153, 194, 240, 260, 283 and 300 K, were determined. (author)

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

International Nuclear Information System (INIS)

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

1976-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-10-15

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

In vivo dosimetry with semiconductor and thermoluminescent detectors applied to head and neck cancer treatment; Dosimetria in vivo com uso de detectores semicondutores e termoluminescentes aplicada ao tratamento de cancer de cabeca e pescoco

Energy Technology Data Exchange (ETDEWEB)

Viegas, Claudio Castelo Branco

2003-03-15

In vivo dosimetry in radiotherapy, i. e, the assessment of the doses received by patients during their treatments, permits a verification of the therapy quality. A routine of in vivo dosimetry is, undoubtedly, a direct benefit for the patient. Unfortunately, in Brazil and in Latin America this procedure is still a privilege for only a few patients. This routine is of common application only in developed countries. The aim of this work is to show the viability and implementation of a routine in vivo dosimetry, using diodes semiconductors and thermoluminescent dosimeters (TLD), at the radiotherapy section of the National Institute of Cancer in Brazil, in the case of head and neck cancer treatment. In order to reach that aim, the characteristics of the response of diodes ISORAD-p and LiF:Mg;Ti (TLD-100) thermoluminescent detectors in powder form were determined. The performance of those detectors for in vivo dosimetry was tested using an RANDO Alderson anthropomorfic phantom and, once their adequacy proved for the kind of measurements proposed, they were used for dose assessment in the case of tumour treatments in the head and neck regions, for Cobalt-60 irradiations. (author)

The properties of CaF2:Dy used as a thermoluminescent dosimeter at low doses

International Nuclear Information System (INIS)

Budd, T.

1976-05-01

Chips of CaF 2 :Dy have been studied to assess their usefulness as a thermoluminescent dosimeter for the measurement of doses of the order of 1 mrad in water. The glow curve structure and the total light output from peaks below about 240 0 C have both been studied. Experiments have been done to study linearity, fading and energy dependence. Fading was found to be 15% in the first day and a further 21% over four weeks. The response of the material per rad in water showed a peak at 30 keV where the sensitivity was 17.5 times the value at 1 MeV. Doses of 0.1 mrad have been assessed with a standard deviation of 25%. (author)

Thermoluminescence of strontium tetraborate

International Nuclear Information System (INIS)

Santiago, M.; Caselli, E.; Lester, M.

1999-01-01

The thermoluminescent properties of crystalline strontium tetraborate are reported. Without activators it has an efficiency comparable to that of TLD-700 powder. Its fading after 40 days amount to less than 2%. The isometric plot shows that most of the emitted light is concentrated at wavelengths ranging from 350 to 450 nm, which accounts partially for the high efficiency. (author)

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-10-15

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

Measurement assurance studies of high-energy electron and photon dosimetry in radiation-therapy applications

Energy Technology Data Exchange (ETDEWEB)

Ehrlich, M; Soares, C G [National Bureau of Standards, Washington, DC (USA)

1981-08-01

This is a brief review of surveys on the dosimetry of radiation-therapy beams by the National Bureau of Standards (NBS). Covered are the NBS ferrous-sulfate (Fricke) dosimetry service, a recently completed survey carried out with thermoluminescence dosimeters (TLD) on the dosimetry in cobalt-60 teletherapy beams, and plans for a TLD survey of dosimetry in high-energy bremsstrahlung beams.

Measurement assurance studies of high-energy electron and photon dosimetry in radiation-therapy applications

International Nuclear Information System (INIS)

Ehrlich, M.; Soares, C.G.

1981-01-01

This is a brief review of surveys on the dosimetry of radiation-therapy beams by the National Bureau of Standards (NBS). Covered are the NBS ferrous-sulfate (Fricke) dosimetry service, a recently completed survey carried out with thermoluminescence dosimeters (TLD) on the dosimetry in cobalt-60 teletherapy beams, and plans for a TLD survey of dosimetry in high-energy bremsstrahlung beams. (author)

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

Quality control in medical radiology using T.L.D

International Nuclear Information System (INIS)

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

2006-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2004-07-01

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

Performance and type testing of selected dosimeters used for individual monitoring

International Nuclear Information System (INIS)

Almhena, E. H. Y.

2010-07-01

This study describes calibration and performance testing carried out for a set of 14 electronic personal dosimeters (EPDs) and thermoluminescence dosimeters (TLDs ) at the Secondary Standard Dosimetry Laboratory of Sudan. Also the conversion coefficients from air kerma have been determined. Dosimeters tested are belonging to three manufactures representing most commonly used types in Sudan. Calibrations were carried out at three X-ray qualities: 80, 120 and 150 kV, ISO 'narrow' spectra and for ''1''3''7Cs, '' 60 Co gamma rays. The experiments were carried out using ICRU Slab phantom with dimension 30x30x15 cm. Secondary standard ionization chamber was used to measure the personal dose equivalent, Hp(10) as standard dosimetric quantity of interest. parameters tested include: The variation of response with radiation energy and angle of incident in addition to dose rate dependence. The angular dependence factors have been experimentally determined for the same qualities and for different angles (0, ±20, ±40, ±60u) + were performed in accordance to the relevant international standards. Excellent energy, angular and dose rate response was demonstrated for 662 137 Cs, 1250 60 Co beam and (118, 100,65 keV) x-ray beam qualities exception the EPD at PM1203M are slightly larger but still with the acceptable. The response of electronic dosimeters were found to in limits of acceptable performance. For the mean response of all energies is range of EPDs Type RADOS 60, Greatz ED 150, Polimaster PM1203M, TLD were (0.75 ±0.08- 1.13±0.13), (0.83±0.29 -1.06±0.07), (1.08±0.14-1.27±0.09), (0.99±0.05 - 1.14±0.13) respectively. The majority of the dosimeters tested showed good energy and angular response. (Author)

Thermoluminescent Signals Caused by Disturbing Effects

International Nuclear Information System (INIS)

German, U.; Weinstein, M.; Ben-Shachar, B.

1999-01-01

One of the major sources of uncertainty in the measurement of low radiation doses by means of thermoluminescence dosemeters is the presence of disturbing thermoluminescence signals, especially luminescence caused by visible light, and by materials attached to the heated areas. Glow curves of thermoluminescence dosemeters contain useful information that can improve the accuracy and the reliability of the thermoluminescent measurements. The influence of the various disturbing effects can be recognised in the shape of the glow curves and can sometimes be separated from the exposure. Some examples are presented of signals arising from the two disturbing effects mentioned above, the signal contributed by Teflon used in the TLD-100 cards of Bicron/Harshaw and some abnormal glow curves due to dirt attached to the cards. Subtraction of the contributions due to these effects is suggested to obtain the net exposure signal. (author)

Natural dose level determination at Johor State with thermoluminescence dosimetry

International Nuclear Information System (INIS)

Ahmad Termizi Ramli; Yusof Jasman

1995-01-01

This paperwork presented the results of using thermoluminescence dosimetry (TLD) method in measuring background dose level, which is done at State of Johor, South Malaysia. The problems faced also discussed

MO-A-BRB-00: TG191: Clinical Use of Luminescent Dosimeters

Energy Technology Data Exchange (ETDEWEB)

NONE

2016-06-15

This presentation will highlight the upcoming TG-191 report: Clinical Use of Luminescent Dosimeters. Luminescent dosimetry based on TLD and OSLD is a practical, accurate, and precise technique for point dosimetry in medical physics applications. The charges of Task Group 191 were to detail the methodologies for practical and optimal luminescent dosimetry in a clinical setting. This includes (1) To review the variety of TLD/OSL materials available, including features and limitations of each. (2) To outline the optimal steps to achieve accurate and precise dosimetry with luminescent detectors and to evaluate the uncertainty induced when less rigorous procedures are used. (3) To develop consensus guidelines on the optimal use of luminescent dosimeters for clinical practice. (4) To develop guidelines for special medically relevant uses of TLDs/OSLs (e.g., mixed field i.e. photon/neutron dosimetry, particle beam dosimetry, skin dosimetry). While this report provides general guidelines for arbitrary TLD and OSLD processes, the report, and therefore this presentation, provide specific guidance for TLD-100 (LiF:Ti,Mg) and nanoDot (Al2O3:C) dosimeters because of their prevalence in clinical practice. Learning Objectives: Understand the available dosimetry systems, and basic theory of their operation Understand the range of dose determination methodologies and the uncertainties associated with them Become familiar with special considerations for TLD/OSLD relevant for special clinical situations Learn recommended commissioning and QA procedures for these dosimetry systems.

MO-A-BRB-01: TG191: Clinical Use of Luminescent Dosimeters

Energy Technology Data Exchange (ETDEWEB)

Kry, S. [UT MD Anderson Cancer Center (United States)

2016-06-15

This presentation will highlight the upcoming TG-191 report: Clinical Use of Luminescent Dosimeters. Luminescent dosimetry based on TLD and OSLD is a practical, accurate, and precise technique for point dosimetry in medical physics applications. The charges of Task Group 191 were to detail the methodologies for practical and optimal luminescent dosimetry in a clinical setting. This includes (1) To review the variety of TLD/OSL materials available, including features and limitations of each. (2) To outline the optimal steps to achieve accurate and precise dosimetry with luminescent detectors and to evaluate the uncertainty induced when less rigorous procedures are used. (3) To develop consensus guidelines on the optimal use of luminescent dosimeters for clinical practice. (4) To develop guidelines for special medically relevant uses of TLDs/OSLs (e.g., mixed field i.e. photon/neutron dosimetry, particle beam dosimetry, skin dosimetry). While this report provides general guidelines for arbitrary TLD and OSLD processes, the report, and therefore this presentation, provide specific guidance for TLD-100 (LiF:Ti,Mg) and nanoDot (Al2O3:C) dosimeters because of their prevalence in clinical practice. Learning Objectives: Understand the available dosimetry systems, and basic theory of their operation Understand the range of dose determination methodologies and the uncertainties associated with them Become familiar with special considerations for TLD/OSLD relevant for special clinical situations Learn recommended commissioning and QA procedures for these dosimetry systems.

MO-A-BRB-01: TG191: Clinical Use of Luminescent Dosimeters

International Nuclear Information System (INIS)

Kry, S.

2016-01-01

This presentation will highlight the upcoming TG-191 report: Clinical Use of Luminescent Dosimeters. Luminescent dosimetry based on TLD and OSLD is a practical, accurate, and precise technique for point dosimetry in medical physics applications. The charges of Task Group 191 were to detail the methodologies for practical and optimal luminescent dosimetry in a clinical setting. This includes (1) To review the variety of TLD/OSL materials available, including features and limitations of each. (2) To outline the optimal steps to achieve accurate and precise dosimetry with luminescent detectors and to evaluate the uncertainty induced when less rigorous procedures are used. (3) To develop consensus guidelines on the optimal use of luminescent dosimeters for clinical practice. (4) To develop guidelines for special medically relevant uses of TLDs/OSLs (e.g., mixed field i.e. photon/neutron dosimetry, particle beam dosimetry, skin dosimetry). While this report provides general guidelines for arbitrary TLD and OSLD processes, the report, and therefore this presentation, provide specific guidance for TLD-100 (LiF:Ti,Mg) and nanoDot (Al2O3:C) dosimeters because of their prevalence in clinical practice. Learning Objectives: Understand the available dosimetry systems, and basic theory of their operation Understand the range of dose determination methodologies and the uncertainties associated with them Become familiar with special considerations for TLD/OSLD relevant for special clinical situations Learn recommended commissioning and QA procedures for these dosimetry systems.

MO-A-BRB-00: TG191: Clinical Use of Luminescent Dosimeters

International Nuclear Information System (INIS)

2016-01-01

This presentation will highlight the upcoming TG-191 report: Clinical Use of Luminescent Dosimeters. Luminescent dosimetry based on TLD and OSLD is a practical, accurate, and precise technique for point dosimetry in medical physics applications. The charges of Task Group 191 were to detail the methodologies for practical and optimal luminescent dosimetry in a clinical setting. This includes (1) To review the variety of TLD/OSL materials available, including features and limitations of each. (2) To outline the optimal steps to achieve accurate and precise dosimetry with luminescent detectors and to evaluate the uncertainty induced when less rigorous procedures are used. (3) To develop consensus guidelines on the optimal use of luminescent dosimeters for clinical practice. (4) To develop guidelines for special medically relevant uses of TLDs/OSLs (e.g., mixed field i.e. photon/neutron dosimetry, particle beam dosimetry, skin dosimetry). While this report provides general guidelines for arbitrary TLD and OSLD processes, the report, and therefore this presentation, provide specific guidance for TLD-100 (LiF:Ti,Mg) and nanoDot (Al2O3:C) dosimeters because of their prevalence in clinical practice. Learning Objectives: Understand the available dosimetry systems, and basic theory of their operation Understand the range of dose determination methodologies and the uncertainties associated with them Become familiar with special considerations for TLD/OSLD relevant for special clinical situations Learn recommended commissioning and QA procedures for these dosimetry systems.

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.

Custom synthesized diamond crystals as state of the art radiation dosimeters

International Nuclear Information System (INIS)

Keddy, R.J.; Nam, T.L.; Fallon, P.J.

1991-01-01

The fact that as a radiation detector, diamond is a stable, non-toxic and tissue equivalent (Z = 6) material makes it an ideal candidate for in vivo radiation dosimetry or the dosimetry of general radiation fields in environmental monitoring. Natural diamond crystals, however, have the disadvantage that no two crystals can be guaranteed to have the same response characteristics. This disadvantage can be overcome by synthesizing the crystals under controlled conditions and by using very selective chemistry. Such synthetic diamonds can be used as thermoluminescence dosimeters where they exhibit characteristics comparable to presently available commercial TLD's or they can be used as ionization chambers to produce either ionization currents or pulses where the small physical size of the diamond (1 mm 3 ) and possibilities of digital circuitry makes miniaturization an extremely attractive possibility. It has also been found that they can perform as scintillation detectors. Aspects of the performance characteristics of such diamonds in all three modes are described

Neutron dosimetry using activation of thermoluminescent CaSO 4

Science.gov (United States)

Azorín, Juan; Gutiérrez, Alicia

1984-11-01

Sulfur activation in calcium sulfate doped with dysprosium (CaSO 4:Dy) thermoluminescent powder, which is bound in pure sulfur, has been used to measure the fast neutron dose at the tangential beam port of a Triga Mark III reactor. After a post-irradiation time of 3 d, the dosimeters were annealed at 600°C for 30 min in order to erase all the thermoluminescence acquired during the irradiation. The dosimeters were then stored to allow self-irradiation by betas from 32P produced by sulfur activation. The thermoluminescent signal accumulated during a post-irradiation time of 20 d due to a neutron fluence of 2.2 × 10 11 n/cm 2 was equivalent to an absorbed dose of 10 mGy of 60Co gamma rays. The thermoluminescence as a function of fast neutron dose fitted to a straight line on a log-log scale from 1 Gy to 10 4Gy.

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

International Nuclear Information System (INIS)

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

2016-01-01

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

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

Thermoluminescent dosimetry of critical organs in CT pediatric patients

International Nuclear Information System (INIS)

Azorin, Juan; Tabares, Musel

2008-01-01

This paper presents the determination of absorbed dose in critical organs of pediatric patients submitted to head computed tomography (CT) studies. This research included patients up to 16 years old submitted to head CT studies using a Siemens Somaton 16 plus multislice CT scanner. Doses were measured using locally made LiF: Mg,Cu,P + PTFE thermoluminescent dosimeters (TLD) due to its tissue equivalence and low fading. Results showed that both the organ absorbed doses and the volume computed tomography dose index (CTDI vol ) determined for simple studies were half of those obtained for contrasted studies. In the case of head three-dimensional reconstruction CT studies the CTDI vol value obtained was almost the same that the obtained for simple CT studies but the organ doses were significantly different. These results suggest that the CTDI vol value is a good indication for choosing the exposure parameters of the CT studies and is useful in the determination of the effective dose but it is not related with the organ doses. (author)

Obtention of a thermoluminescent material for dosimetry of ionizing radiation; Obtencion de un material termoluminiscente para dosimetria de la radiacion ionizante

Energy Technology Data Exchange (ETDEWEB)

Gonzalez M, P R

1990-07-01

The thermoluminescent dosemeters are small crystals which suffer changes in their structure by the radiation effect, being displaced the electrons toward higher energy levels. On heating the previously irradiated crystals, the electrons come back to their base state emitting light photons. The light quantity emitted is proportional to the received radiation dose. The light quantity emitted is proportional to the received radiation dose. The lithium fluoride is one of the thermoluminescent materials considered as tissue equivalents by having a low effective atomic number (Z{sub ef}). At present, the more used commercial product used of this type is the TLD-100*. In this work the obtained results in the preparation of the lithium fluoride thermoluminescent material are presented. This is activated with magnesium (Mg) and titanium (Ti), which we have labelled as: LiF: Mg, Ti. The results from the tests performed for verifying his thermoluminescent properties are presented too, as powder form as in pellets form. These tests were performed in simultaneous form with TLD-100 samples, which is considered as reference. The LiF: Mg, Ti thermoluminescent material manufactured in the ININ presents similar dosimetric characteristics to those ones of the TLD-100. Therefore being able to replace the imported dosemeters. * (TLD-100 is a commercial trademark registered by Harshaw/Filtrol (US) for LiF: Mg, Ti Tl dosemeters) (Author)

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

International Nuclear Information System (INIS)

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

2015-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-06-15

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

Angular dependence of optical fibre thermoluminescent dosimeters irradiated using kilo- and megavoltage X-rays

International Nuclear Information System (INIS)

Moradi, F.; Ung, N.M.; Mahdiraji, G.A.; Khandaker, M.U.; Entezam, A.; See, M.H.; Taib, N.A.; Amin, Y.M.; Bradley, D.A.

2017-01-01

Prior investigation of the suitability of optical fibres as thermoluminescent dosimeters for diagnostic and therapeutic radiation beams has not included detailed study of the effect of beam angulation. Present study of such response has made use of optical fibre of cylindrical shape, exposed to 30 kVp photons from an X-ray tube and a 6 MV photon beam from a linear accelerator. The effect of the irradiation medium was also studied, comparing response free-in-air against on-surface and in-depth irradiations through use of solid-water™ phantom. Standard optical fibre (ø =125 µm) shows non-uniform response to beams delivered at different incident angles. Monte Carlo simulation provided support for the experimental results, also obtaining absorbed dose in the fibres. The results of free-in-air condition simulated with mono-energy beam show angle-independent response for photons within the energy range 100–500 keV, while dependency has been observed for beam energies of <100 keV and >500 keV. Experimentally, the angular dependency up to 35% is observed in 30 kVp free-in-air, while in 6 MeV beam, this is reduced to 20%, 10%, and 3% in free-in-air, on phantom surface, and in-depth conditions, respectively. The observations have been justified by considering the range of secondary electrons in the dosimeter and the effect of scattered radiation. - Highlights: • Irradiated free-in-air standard optical fibre dosimeters show significant angular dependence. • The dependency varies for photon energies obtained at kVp and MV potentials. • The irradiation medium influences the angular dependence. • With MeV beam irradiations under CPE conditions the angular dependence decreases to 3%.

An intercomparison of the thermoluminescent efficiency of various preparations of lithium fluoride

CERN Document Server

Driscoll, C M H

1977-01-01

Possible alternative sources of supply of lithium fluoride to that used at present in the NRPB automated TLD system dosemeter are being considered on the grounds of economy and quality control. Initial measurements on the thermoluminescent properties and efficiency of various preparations of lithium fluoride are described, including the Harshaw TLD-700 which is currently in use in the automated thermoluminescent dosemeter. Material obtained from British Nuclear Fuels Ltd (which may be an atypical batch) showed 75% of the sensitivity of the Harshaw material, with around 20% fading of the signal after 1 month's storage. French material, obtained from Desmarquest and Carbonisation Entreprise et Ceramique and used by the Commissariat a l'Energie Atomique, showed good fading resistance but, after standard preparational treatments, was only half as sensitive in the thermoluminescent response. Without additional treatments to improve the characteristics of these materials, they cannot be considered as being satisfac...

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

International Nuclear Information System (INIS)

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

2016-10-01

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

Pulse monitor for upper extremities dosimetry in nuclear medicine

International Nuclear Information System (INIS)

Cledison de Jesus, Cunha; Divanizia do Nascimento, Souza

2006-01-01

In the manipulation of radioactive materials in Nuclear Medicine service the body parts of workers that are more displayed to the ionizing radiation are hands, underarm and arm. Therefore is necessary to developing personal dosimeters to monitoring of easy reproduction and low cost with purpose to determine the doses level radiation received by the worker in these extremities. However thermoluminescent dosimeters do not provide an instantaneous exposure reading, they are suitable for personal dosimetry because of their following advantages: wide useful dose range, small physical size and no need for high voltage or cables, i.e. stand alone character. The aim of this work is to investigation of a new pulse monitor, that has been developing with thermoluminescent detectors of CaSO 4 :Dy (TLD) using a small plate of acrylic, perforated cardboard to deposit the TLD. This set was involved in plastic to protect from humidity and other harmful ambient factors; moreover, a bracelet was inserted, adaptable for any worker. During the preparation of the personal dosimeters to monitor exposure it was necessary to verify their effectiveness to use by workers in a nuclear medicine service. The monitors have been submitted to procedures of performance evaluations by several tests: badges homogeneity, reproducibility, linearity, low detection limit, auto-irradiation, dosimeters stability, verification of the residual T.L. signal, visible light effect on dosimeters, energetic and angular dependence and TLD answer by influence of a simulator during radiation. Was possible to verify the efficiency of such upper extremities dosimeters and were obtained satisfactory results within of the limits demanded in the described tests above to this type of personal dosimeters. (authors)

Thermoluminescence dosimeters with narrow bandpass filters

Science.gov (United States)

Walker, Scottie W.

2004-07-20

A dosimetry method exposes more than one thermoluminescence crystals to radiation without using conventional filters, and reads the energy stored in the crystals by converting the energy to light in a conventional manner, and then filters each crystal output in a different portion of the spectrum generated by the crystals.

Method of making isodose curve using thermoluminescence dosemeter

International Nuclear Information System (INIS)

Bakar Ramain, A.

1975-01-01

Line source of 60 Co in the form of needles and tubes are extensively used in radiotherapy in moulds, implants, and intracavitary techniques for the treatment of malignant lesions. It is important to have isodose distributions in tissue for those source for purposes of treatment planning. The isodose distributions have been obtained experimentally by using tinny lithium-fluoride (Lsub(i)F) thermoluminescent dosemeters (TLD) and they are compared to the theoretical results. The distinct advantages of Lsub(i)F (TLD) in such measurements are briefly discussed. (author)

1987 Neutron and gamma personnel dosimeter intercomparison study using a D2O-moderated 252Cf source

International Nuclear Information System (INIS)

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

1989-05-01

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

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)

VALIDATION OF HANFORD PERSONNEL AND EXTREMITY DOSIMETERS IN PLUTONIUM ENVIRONMENTS

Energy Technology Data Exchange (ETDEWEB)

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

2000-02-10

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

Measurement of gamma radiation doses at the RA reactor by thermoluminescent dosemeters

International Nuclear Information System (INIS)

Prokic, M.

1974-01-01

This paper presents the procedures and gamma radiation doses measured at the exit from the horizontal experimental channel HK-5, vertical experimental channel VK-5 and in the thermal column of the RA reactor in Vinca. Measurement of gamma radiation dose in the mixed intense gamma and neutron radiation field was done by two types of thermoluminescent dosemeters, LiF (TLD-700) and CaF 2 (TLD-08). Gamma dose in the VK-5 was measured in the air and on the bottle filled with tissue-equivalent solution. Increase of the dose on the surface of the bottle was 2.3 compared to the gamma dose value in the air. Correction for the influence of neutrons having different energies was done by using the known sensitivity values of both TL dosemeter types for thermal, intermediate and fast neutrons. Results showed that the TLD-700 dosemeter contains 5 time more Li-6 isotopes (0.035%) than the declared value causing increased neutron sensitivity of this dosemeter. This paper includes numerical sensitivity data for neutrons of different energies for both types of TL dosemeters. Neutron sensitivity values for TLD-700 are related to LiF with 0.035% of Li-6 isotope. Result of measurement have also shown that the CaF 2 :Mn (TLD-08) thermoluminescent dosemeter is more suitable for gamma radiation dose measurements in mixed n-gamma fields with intensive neutron fluxes due to lower neutron sensitivity compared to TLD-700 [sr

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

International Nuclear Information System (INIS)

Gail de Planque, E.

1984-01-01

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

In vivo dosimetry using thermoluminescent detector in cancer therapy of head and neck

International Nuclear Information System (INIS)

Viegas, Claudio C.B.; Batista, D.V.; Campos, A.M.; Lopes, R.T.

2002-01-01

The viability and implementation of a routine in vivo dosimetry, using thermoluminescent dosemeters (TLD), at the radiotherapy section of the National Institute of Cancer in Brazil, in the case of head and neck treatment is shown. In order to reach that aim, the characteristics of the response of the LiF:Mg;Ti (TLD-100) thermoluminescent detectors in powder form were determined. The performed of this detector for in vivo dosimetry was testes using an RANDO Alderson anthropomorphic phantom and, once their adequability proved for the kind of measurements proposed , it was used for dose assessment in the case of tumour treatments in the head and neck regions, for Cobalt-60 irradiations. (author)

Temperature measurement device

International Nuclear Information System (INIS)

Oltman, B.G.; Eckerman, K.F.; Romberg, G.P.; Prepejchal, W.

1975-01-01

Thermoluminescent dosimeter (TLD) material is exposed to a known amount of radiation and then exposed to the environment where temperature measurements are to be taken. After a predetermined time period, the TLD material is read in a known manner to determine the amount of radiation energy remaining in the TLD material. The difference between the energy originally stored by irradiation and that remaining after exposure to the temperature ofthe environment is a measure of the average temperature of the environment during the exposure. (U.S.)

Study of some thermoluminescent phosphors for the dosimetry of ionizing radiations

International Nuclear Information System (INIS)

Jaafari, M.

1983-01-01

Thermoluminescence dosimetry techniques are reviewed and interactions radiation matter are recalled. The need for new phosphors is evidenced. Numerous phosphors are examined and calcium, strontium and barium sulfides are synthetized and deposited on glass supports. The thermoluminescence of the dosimeters obtained with these materials is analyzed [fr

Performance of neutron and gamma personnel dosimetry in mixed radiation fields

International Nuclear Information System (INIS)

Swaja, R.E.; Sims, C.S.

1981-01-01

From 1974 to 1980, six personnel dosimetry intercomparison studies (PDIS) were conducted at the Oak Ridge National Laboratory (ORNL) to evaluate the performance of personnel dosimeters in a variety of neutron and gamma fields produced by operating the Health Physics Research Reactor (HPRR) in the steady state mode with and without spectral modifying shields. A total of 58 different organizations participated in these studies which produced approximately 2000 measurements of neutron and gamma dose equivalents on anthropomorphic phantoms for five different reactor spectra. Based on these data, the relative performance of three basic types of neutron dosimeters [nuclear emulsion film, thermoluminescent (TLD), and track-etch] and two basic types of gamma dosimeters (film and TLD) in mixed radiation fields was assessed

TLD audit in radiotherapy in the Czech Republic

International Nuclear Information System (INIS)

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

1998-01-01

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

Outdoor and indoor dose assessment using environmental thermoluminescence dosimeters (TLDs) in Costa Rica

International Nuclear Information System (INIS)

Mora, Patricia

2003-01-01

Costa Rica lies at the intersection of the Cocos and Caribbean plates in Central America. It has mountain ranges with many active volcanoes along its territory. Its soils are predominantly of volcanic origin. Natural radiation measurements utilising environmental CaF 2 :Dy thermoluminescence dosimeters were used for the first time in Costa Rica by the Dosimetry Section of the Atomic, Nuclear and Molecular Sciences Research Center of the University of Costa Rica. Seven hundred outdoor measurements were obtained in a 3.5-year period at eight different sites throughout the country. One hundred and seventy-four indoor readings were also collected at four sites for a 2-year period. Population-weighted averages give 82 nGy h -1 for outdoors and 130 nGy h -1 for indoors. The values lie on the upper range of worldwide reported values due to reported soil characteristics rich in uranium and potassium. A preliminary population-weighted value of 0.74 mSv/year for the effective dose is calculated for natural terrestrial gamma radiation in Costa Rica

Radiation monitoring at Pakistan research reactor

International Nuclear Information System (INIS)

Ali, A.

1984-05-01

Area radiation monitoring is accomplished by using Tracer Lab. radiation monitor. Personnel monitoring is carried out using film badges, TLDs (Thermoluminescent Dosimeters) and pocket dosimeters. For the evaluation of monthly accumulated doses of radiation workers film badges/TLDs and for instantaneous/short term dose measurement in higher radiation zones pocket dosimeters are used in addition to film badge/TLD. Environmental monitoring is necessary to check the PARR operation effect on background radiation level in the vicinity of PINSTECH. (A.B.). 4 refs

Commissioning and characteristics of MOSFET dosimeter

International Nuclear Information System (INIS)

Gopiraj, A.; Billimagga, Ramesh S.; Rekha, M.; Ramasubramaniam, V.

2007-01-01

The verification of the dose delivered to a patient is an important part of the quality assurance in radiotherapy. Thermoluminescent dosimeters (TLDs) and semiconductor diodes were mostly used for this purpose. Recently Metal Oxide Semiconductor field effect transistors (MOSFET) have been proposed for the application in radiotherapy. Each type of detector has its own advantages and disadvantages. The TLD size is very small and therefore can be used both for measurement and dose delivered to a patient and for measurements of dose distribution in a humanoid phantom. The main disadvantages of the TLDs are the time required by the preparation procedure and the limited accuracy which depends on the experience of the user. Additionally, TLDs do not allow an immediate readout. The main disadvantages of semiconductor diodes are the necessity of using a cable which can disturb normal clinical work especially when in vivo measurements are carried out, and the necessity of applying of many correction factors to achieve high accuracy. We procured MOSFET system from Thomson and Nielsen Electronic Ltd. The reproducibility as a function of dose and linearity and calibration factor of the MOSFET detectors were measured. The effects of energy, field size and accumulated dose on the response of the detectors were investigated

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

International Nuclear Information System (INIS)

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

2013-01-01

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

A quality audit program for external beam radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Hanson, W.F.; Stovall, M. [Univ. of Texas, Houston, TX (United States)

1993-12-31

For more than 25 years, the University of Texas M. D. Anderson Cancer Center has had a quality audit program using mailed dosimeters to verify radiation therapy machine output. Two programs, one compulsory and one voluntary, presently monitor therapy beams at more than 1000 megavoltage-therapy facilities. A successful program requires two major components: a high-precision thermoluminescent dosimeter (TLD) system and dedicated staff that interact closely with the users to resolve discrepancies. The TLD system, the logistics used, and the human interaction of these programs are described. Examples show that the programs can identify major discrepancies, exceeding 5 %, as well as discrepancies as small as 3%.

A quality audit program for external beam radiotherapy

International Nuclear Information System (INIS)

Hanson, W.F.; Stovall, M.

1993-01-01

For more than 25 years, the University of Texas M. D. Anderson Cancer Center has had a quality audit program using mailed dosimeters to verify radiation therapy machine output. Two programs, one compulsory and one voluntary, presently monitor therapy beams at more than 1000 megavoltage-therapy facilities. A successful program requires two major components: a high-precision thermoluminescent dosimeter (TLD) system and dedicated staff that interact closely with the users to resolve discrepancies. The TLD system, the logistics used, and the human interaction of these programs are described. Examples show that the programs can identify major discrepancies, exceeding 5 %, as well as discrepancies as small as 3%

Effect of surface contaminants on the light emission spectrum of LiF TLDs

International Nuclear Information System (INIS)

Abhold, M.E.

1987-01-01

Recent results show the differences between the light emissions spectra from LiF Thermoluminescent Dosimeters (TLDs) for gamma vs. alpha irradiations to be due to contaminants on the surface of the TLD. The light emission spectrum for thermal neutron irradiations was observed to be identical to that for a Cs-137 gamma irradiation in Harshaw TLD-100. Further experiments with surface treatments on TLD-100 indicate trace contaminants introduced by the standard methanol cleansing rinse in reagent grade methanol to have a substantial effect on the light emission spectrum for Am-241 alpha irradiations

The results of dosimetric type tests on the sample of LiF:Mg,Ti thermoluminescence dosimeters produced in Iran

International Nuclear Information System (INIS)

Jafarizadeh, M.; Hosseini Pooya, S. M.; Firoozi, B.; Kamali Shoroodani, A. R.; Mohammadi, Kh.

2011-01-01

In this investigation, the standard type tests performed on the LiF:Mg,Ti chip samples which have been produced in Iran. The dosimetry tests are consisting of sensitivity, homogeneity, linearity, reproducibility, minimum measurable dose, self and residual doses. The obtained results show that some of the tests such as sensitivity, minimum measurable dose, self and residual doses fulfill the criteria given by IEC 61066 and ASTM E668 standards; however, the remaining tests show some discrepancies in comparison with the standards. Also the sensitivity was measured to be 0.92 of that of commercially available TLD-100 (Harshaw) sample. So, the produced LiF:Mg,Ti dosimeter can be used in a routine personal/environmental and medical dosimetry with considering its precision.

Analytical evaluation of dose measurement of critical accident at SILENE (Contract research)

CERN Document Server

Nakamura, T; Tonoike, K

2003-01-01

Institute for Radioprotection and Nuclear Safety (IRSN) and the OECD Nuclear Energy Agency (NEA) jointly organized SILENE Accident Dosimetry Intercomparison Exercise to intercompare the dose measurement systems of participating countries. Each participating country carried out dose measurements in the same irradiation field, and the measurement results were mutually compared. The participated in the exercise to measure the doses of gamma rays and neutron from SILENE by using thermoluminescence dosimeters (TLD's) and an alanine dosimeter. In this examination, the derived evaluation formulae for obtaining a tissue-absorbed dose from measured value (ambient dose equivalent) of TLD for neutron. We reported the tissue-absorbed dose computed using this evaluation formula to OECD/NEA. TLD's for neutron were irradiated in the TRACY facility to verify the evaluation formulae. The results of TLD's were compared with the calculations of MCNP and measurements with alanine dose meter. We found that the ratio of the dose b...

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

Study on carbonated hydroxyapatite as a thermoluminescence dosimeter

International Nuclear Information System (INIS)

Shafaei, M.; Sardari, D.; Ziaie, F.; Larijani, M.M.

2015-01-01

In this study, carbonated hydroxyapatite nanoparticles were used for thermoluminescence dosimetry. The nano-structure carbonated hydroxyapatite synthesized via hydrolysis of CaHPO 4 and CaCO 3 . The obtained nano powders were characterized by XRD technique and FTIR spectroscopy system. The carbonated hydroxyapatite samples were irradiated at different doses using 60 Co gamma rays, and were subjected to thermoluminescence measurement system, consequently. The TL glow curve exhibited two distinguishable peaks centered at around of 165 C and 310 C. The TL response of carbonated hydroxyapatite samples as a function of absorbed dose was linear in the range of 25-1000 Gy. Other dosimetric features of the carbonated hydroxyapatite nanoparticles including fading and reproducibility were also investigated.

Calibration of an ALBEDO termoluminiscent dosimeter for its use in personal dosimetry

International Nuclear Information System (INIS)

Diaz Bernal, E.; Molina Perez, D.; Cornejo Diaz, N.; Carrazana Gonzalez, J.

1996-01-01

The dosimetric studies began after the Radiological Individuals Surveillance Department from the Radiation Protection and Hygiene Center acquired the albedo thermoluminescent dosimeters model JR1104. This paper reviews the response of those dosimeters to the different spectrums and incidence angles of neutronic radiation

A TLD-based personal dosemeter system for air crew monitoring

International Nuclear Information System (INIS)

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

2003-01-01

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

Establishment of Ge-doped optical fibres as thermoluminescence dosimeters for brachytherapy

International Nuclear Information System (INIS)

Issa, Fatma; Abdul Rahman, A.T.; Hugtenburg, Richard P.; Bradley, David A.; Nisbet, Andrew

2012-01-01

This study aims to establish the sensitive, ∼120 μm high spatial resolution, high dynamic range Ge-doped optical fibres as thermoluminescence (TL) dosimeters for brachytherapy dose distribution. This requires investigation to accommodate sensitivity of detection, both for the possibility of short range dose deposition from beta components as well as gamma/x-mediated dose. In-air measurements are made at distances close to radionuclide sources, evaluating the fall off in dose along the transverse axis of 133 Ba and 60 Co radioactive sources, at distances from 2 mm up to 20 mm from their midpoints. Measurements have been compared with Monte Carlo code DOSRZnrc simulations for photon-mediated dose only, agreement being obtained to within 3% and 1% for the 133 Ba and 60 Co sources, respectively. As such, in both cases it is determined that as intended, beta dose has been filtered out by source encapsulation. - Highlights: ► We seek to establish Ge-doped optical fibres as TLDs for brachytherapy. ► Dose was evaluated along the central axis of 133 Ba and 60 Co, at 2 mm–20 mm. ► We verify values using DOSRZnrc Monte Carlo code simulations. ► Good agreement is between dose measurements and calculation to within 3% and 1%. ► Methodology is to be used in obtaining doses around 125 I and 192 Ir sources.

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

International Nuclear Information System (INIS)

Luo Huiyong; Wen Qinghua; Li Ruirong; Yu Enjian

2006-01-01

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

Solid thermoluminescent dosemeter of sodium tetraborate and brazilian fluoride sensitive to thermal neutrons

International Nuclear Information System (INIS)

Fratin, L.

1988-01-01

The techniques of compacting sodium tetraborate and natural fluoride mixtures were studied in this work, with the aim of producing a solid dosimeter sensitive to thermal neutrons. The production procedure involves the vitrification of the sodium tetraborate, the grinding, mixture, cold pressing and the sinterization of the pellets. A special arrangement was built for irradiation where paraffin was used as moderator for neutrons from a 241 Am-Be source. Two different mass ratios of sodium tetraborate and flourite showed a linear thermoluminescent response to the neutron fluence in the range of 1.0 to 7.0 x 10 8 n (sub)tcm -2 . Solid dosimeters, manufactured from natural fluorite and sodium chloride, showed a response to gamma radiation similar to the response of the dosimeters sensitive to neutrons. These dosimeters are need to identify the proportion of thermoluminescent response due to gamma radiation present in a neutron field. (author) [pt

Ceramic BeO exoelectron dosimeters for tritium and radon monitoring

International Nuclear Information System (INIS)

Gammage, R.B.

1979-01-01

An environmental monitoring device with BeO ceramic dosimeters can be used to measure 222 Rn in dwellings. Radon diffuses into a porous hemispheric chamber and the radon daughters are electrostatically collected on aluminized Mylar foil covering the BeO dosimeter that records the alpha activity. A 10:1 signal-to-background ratio results from a radon exposure of only pCi-h/l. This high sensitivity makes accurate radon measurement possible within one day, even at near background levels of a few tenths pCi/l. The BeO exoelectron dosimeter is also uniquely suited for monitoring occupational exposure to insoluble tritium gas. At one-fifth the maximum permissible concentration, exposure for 8 hours gives a 10:1 signal-to-background exoelectron response to the low energy beta rays. Compensation for any exoelectron response caused by photon radiation can be made by reading the thermoluminescence. The tritium exposure produces negligible thermoluminescence. Progress in these and other applications is now totally dependent on achieving reliability and long-term stability of the exoelectron dosimeter

SSDL Argentina: Dosimetric intercomparison programme for cobalt 60 therapy units

Energy Technology Data Exchange (ETDEWEB)

Saravi, M; Papadopulos, S; Mugliaroli, H [Comision Nacional de Energia Atomica, Buenos Aires (Argentina)

1996-08-01

Thermoluminescence dosimeters (TLD) are widely used to verify absorbed dose delivered from radiation therapy beams. The Secondary Standard Dosimetry Laboratory (SSDL) of Argentina uses TLD for its mailed dose intercomparison programme for cobalt 60 radiation therapy units. Results obtained since 1978 as well as causes of dose discrepancies greater than 5% are analyzed. Results of the external quality control performed by the IAEA for this programme indicate that the dose evaluated by the SSDL TLD service for the participating centers is about 1% lower than that evaluated by the IAEA TLD service. This deviation is accepted taking on account that a {+-} 2% dose uncertainty for TLD dosimetry is reasonable. (author). 5 refs, 5 figs, 2 tabs.

Determination of radiation direction in environmental monitoring

International Nuclear Information System (INIS)

Campos, Vicente de Paulo de; Moura, Eduardo S.; Rocha, Felicia D.G.; Manzoli, Jose Eduardo

2009-01-01

The assessment of environmental exposure has been performed in Brazil using the thermoluminescence technique at Thermoluminescence Dosimetry Laboratory (LDT), at Nuclear and Energetic Research Institute (IPEN/CNEN-SP). To carry out these measurements, several thermoluminescent dosimeters (TLD's) were used to measure the expose. In this procedure, very few information of direction where the radiation came from is available. A vague supposition about the direction from where the radiation came from could be inferred only by evaluation of multiple dosimeters displaced at entire region of monitoring, but this demand to much effort or sometimes become impractical for certain situations. In this work, a single device is used to provide information about the direction from where the radiation came through. This device is called directional dosimeter (DD). Using more than one DD it is possible to reduce the uncertainty of the measurements and determine the radiation source position. The DD basically consists of a regular solid with high effective atomic number, where one TLD is positioned at each face. The DD allows evaluating the environmental exposure and the direction of the radiation by a simple vector sum. At each face of the DD, it is associated an orthogonal vector, and modulus of this vector represents the correspond exposure measured by the TLD. The direction of the radiation source is the sum of these faces vectors. The prototype used in this work was a lead cube with six TLDs of CaSO 4 :Dy/Teflon. The TLDs have high sensibility and are already used in area, environmental and personal monitoring. The measurements had shown the correct environmental exposure and a good indication of the radiation direction. (author)

Neutron H*(10) estimation and measurements around 18MV linac.

Science.gov (United States)

Cerón Ramírez, Pablo Víctor; Díaz Góngora, José Antonio Irán; Paredes Gutiérrez, Lydia Concepción; Rivera Montalvo, Teodoro; Vega Carrillo, Héctor René

2016-11-01

Thermoluminescent dosimetry, analytical techniques and Monte Carlo calculations were used to estimate the dose of neutron radiation in a treatment room with a linear electron accelerator of 18MV. Measurements were carried out through neutron ambient dose monitors which include pairs of thermoluminescent dosimeters TLD 600 ( 6 LiF: Mg, Ti) and TLD 700 ( 7 LiF: Mg, Ti), which were placed inside a paraffin spheres. The measurements has allowed to use NCRP 151 equations, these expressions are useful to find relevant dosimetric quantities. In addition, photoneutrons produced by linac head were calculated through MCNPX code taking into account the geometry and composition of the linac head principal parts. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-07-01

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

Operating experience of an automated TLD dispensing system at CORAL facility

International Nuclear Information System (INIS)

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

2016-01-01

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

Comparison of two techniques for natural dose measurements

International Nuclear Information System (INIS)

Ekdal, E.; Ege, A.; Goekce, M.; Karali, T.; Derin, Z.

2006-01-01

In the study of luminescence dating, age of an archaeological sample is calculated by the ratio of total exposed dose to annual dose resulted from the environmental radioactivity. Determination of the annual dose level of an archaeological area is one of the most important parameter in calculating the archaeological age of the sample using luminescence techniques. Therefore, the knowledge of the concentrations of the natural radionuclides is important since naturally occurring radioactivity provides major contribution to the annual dose. The natural radioactivity is originated from natural radionuclides consisting mainly of 2 38U, 2 32Th and 4 0K isotopes together with their daughters in soils. In this study, annual dose level of the archaeological site was determined with two different methods: an indirect method that is determining the concentrations of the naturally occurring radioactive elements using gamma spectroscopy and a direct method that uses thermoluminescence dosimeters. Soil samples were collected from the Yesilova Hoeyuek archaeological site located in Izmir City at the Aegean Region of Turkey. The concentrations of the natural radioactivity ( 2 38U, 2 32Th and 4 0K) in soil samples were determined using 3 x 3 N aI (Tl) γ-ray spectrometry system. In direct method, Al 2 O 3 :C thermoluminescence dosimeters (TLD's) were used. These dosimeters were chosen because of their sensitivity and usability in dating studies. They were buried in same archaeological site, 30 cm depth from the soil surface for 30 days period. The luminescence intensity of Al 2 O 3 :C dosimeters was measured by a TLD reader and the dose level was calculated by the luminescence signals emitted by the dosimeters. The results obtained from natural radionuclides and Al 2 O 3 :C thermoluminescence dosimeters were compared and the source of the differences between two methods were discussed

Investigations on thermoluminescent dosimetry (TLD) with doped alumina ceramics

International Nuclear Information System (INIS)

Janas, R.; Huebner, K.

1976-01-01

Alumina ceramics doped and burned under various conditions have been investigated with regard to their suitability for thermoluminescent dosimetry. The production of ceramics is described. The properties essential for dosimetric purposes, such as glow curve, energy dose characteristics, fading, recoverability, lower detection limit and energy dependence, are indicated. The advantages and disadvantages of alumina ceramics are compared. (author)

Ultraviolet dosimetry using thermoluminescent phosphors - an update

International Nuclear Information System (INIS)

Nagpal, J.S.

1998-04-01

Intrinsic response of various thermoluminescent (TL) materials such as CaSO 4 (Dy, Eu, Mn, Sm, Tb, or Tm), LiF (Mg, Cu, P), Mg 2 SiO 4 :Tb, CaF 2 :Dy, CaF 2 :Tb, ThO 2 :Tb and Al 2 O 3 (Si, Ti); cathodoluminescent phosphors Y 3 Al 5 O 12 :Ce, Y 3 Al 5 O 12 :Tb and Y(V,P)O 4 :Eu; and fluorescent lamp phosphors calcium halophosphate (Mn,Sb) and Ce Mg aluminate (Eu, Tb) to ultraviolet (UV) radiations has been studied. Intrinsic TL response of most of the phosphors is rate (radiant flux) dependent. For the first time, UV response of the materials is reported for a fixed total radiant energy (total UV dose), at a single radiant flux (260 μW.cm -2 ), for an appropriate comparison. A wide range of UV sensitivity is observed. Studies conducted using UV radiation from two unfiltered low pressure mercury lamps show significant differences in glow curves, as compared to those obtained with nearly monochromatic UV radiations. Photons of wavelength 365 nm induce bleaching of TL induced by 254 nm photons, in most of the materials. Sequential/tandem exposures to 254 nm and 365 nm photons have yielded new but alarming results in CaF 2 :Tb. Preferential induction and bleaching of specific TL glow peaks by 365 nm and 254 nm photons are interesting characteristics discovered in CaSO 4 :Eu. Photoluminescence studies of Tb 3+ and Eu 3+ activated phosphors have augmented the inferences drawn from the bleaching effects produced by 365 nm photons. Earlier work carried out on phototransferred thermoluminescence of CaSO 4 :Dy-teflon dosimeters, TLD-100, Mg 2 SiO 4 :Tb and Al 2 O 3 (Si,Ti) has also been reviewed. (author)

Type tests to the automatic thermoluminescent dosimetry system acquired by the CPHR for personal dosimetry; Pruebas tipo al sistema de dosimetria termoluminiscente automatico adquirido por el CPHR para dosimetria personal

Energy Technology Data Exchange (ETDEWEB)

Molina P, D.; Pernas S, R.; Martinez G, A. [Centro de Proteccion e Higiene de las Radiaciones (CPHR), Calle 20 No. 4113 e/41 y 47. Playa, C.P. 11300, A.P. 6195, C.P. 10600 La Habana (Cuba)

2006-07-01

The CPHR individual monitoring service acquired an automatic RADOS TLD system to improve its capacities to satisfy the increasing needs of their national customers. The TLD system consists of: two automatic TLD reader, model DOSACUS, a TLD irradiator and personal dosimeters card including slide and holders. The dosimeters were composed by this personal dosimeters card and LiF:Mg,Cu,P (model GR-200) detectors. These readers provide to detectors a constant temperature readout cycle using hot nitrogen gas. In order to evaluate the performance characteristics of the system, different performance tests recommended by the IEC 1066 standard were carried out. Important dosimetric characteristics evaluated were batch homogeneity, reproducibility, detection threshold, energy dependence, residual signal and fading. The results of the tests showed good performance characteristics of the system. (Author)

Dose measurements in dental radiology using thermoluminescent dosimetry

International Nuclear Information System (INIS)

Chiara, Ana Claudia M. de; Costa, Alessandro M.; Pardini, Luiz Carlos

2009-01-01

The aim of this work was the implementation of a code of practice for dosimetry in dental radiology using the technique of thermoluminescent dosimetry. General principles for the use of thermoluminescent dosimeters were followed. The irradiations were performed using ten X-ray equipment for intra-oral radiography and an X-ray equipment for panoramic radiography. The incident air kerma was evaluated for five different exposure times used in clinical practice for intra-oral radiographs. Using a backscatter factor of 1.2, it was observed that approximately 40% of the entrance skin dose values found for intra-oral radiographs are above the diagnostic reference level recommended in national regulation. Different configurations of voltage and current were used representing the exposure as a child, woman and man for panoramic radiographs. The results obtained for the air kerma area product were respectively 53.3 +- 5.2 mGy.cm 2 , 101.5 +- 9.5 mGy.cm 2 and 116.8 +- 10.4 mGy.cm 2 . The use of thermoluminescent dosimetry requires several procedures before a result is recorded. The use of dosimeters with ionization chambers or semiconductors provides a simple and robust method for routine measurements. However, the use of thermoluminescent dosimetry can be of great value to large-scale surveys to establish diagnostic reference levels. (author)

SU-E-T-222: Investigation of Pre and Post Irradiation Fading of the TLD100 Thermoluminescence Dosimetry for Photon Beams

Energy Technology Data Exchange (ETDEWEB)

Sina, S [Radiation Research Center, Shiraz University, Shiraz (Iran, Islamic Republic of); Sadeghi, M [Nuclear Engineering department, Shiraz university, Shiraz (Iran, Islamic Republic of); Faghihi, R [Radiation Research Center, Shiraz University, Shiraz (Iran, Islamic Republic of); Nuclear Engineering department, Shiraz university, Shiraz (Iran, Islamic Republic of)

2014-06-01

Purpose: The pre-irradiation and post-irradiation fading of the Thermoluminescense dosimeter signals were investigated in this study. Methods: Two groups of TLD chips with pre-determined ECC values were used in this study. The two groups were divided into 6 series, each composing of 5 TLD chips.The first group was used for pre-irradiation fading. 5 TLDs were exposed to a known amount of radiation from Cs-137 source, and were read out the next day. After seven days, the other 5 TLDs were exposed to the same amount of radiation and were read out after a day. The other series of 5 TLDs were also exposed after 7,19,28, 59, and 90 days, and were read out a day after irradiation. The loss in TLD signal were obtained for all the above cases. The second group, was used for postirradiation fading. All the TLDs of this group were exposed to a known amount of radiation from Cs-137 source. The 6 series composed of 5 TLDs were read out after 1,7,19,28,59, and 90 days. The above-mentioned procedures for obtaining pre-irradiation, and post-irradiation fading were performed for three storage temperatures (25°C, 4°C, and −18°C). Results: According to the results obtained in this study, in case of pre-irradiation fading study, the signal losses after 90 days are 12%, 24%, and 17% for 25°C, 4°C, and −18°C respectively. In case of post-irradiation fading study, the sensitivity losses after 90 days are 25%, 216%, and 20% for 25°C, 4°C, and −18°C respectively. Conclusion: The results indicate that the optimized time between exposing and reading out, and also the optimized time between annealing and exposing is 1 day.The reduction of Storage temperature will reduce the post-irradiation fading, While temperature reduction does not have any effect on pre-irradiation fading.

SU-E-T-222: Investigation of Pre and Post Irradiation Fading of the TLD100 Thermoluminescence Dosimetry for Photon Beams

International Nuclear Information System (INIS)

Sina, S; Sadeghi, M; Faghihi, R

2014-01-01

Purpose: The pre-irradiation and post-irradiation fading of the Thermoluminescense dosimeter signals were investigated in this study. Methods: Two groups of TLD chips with pre-determined ECC values were used in this study. The two groups were divided into 6 series, each composing of 5 TLD chips.The first group was used for pre-irradiation fading. 5 TLDs were exposed to a known amount of radiation from Cs-137 source, and were read out the next day. After seven days, the other 5 TLDs were exposed to the same amount of radiation and were read out after a day. The other series of 5 TLDs were also exposed after 7,19,28, 59, and 90 days, and were read out a day after irradiation. The loss in TLD signal were obtained for all the above cases. The second group, was used for postirradiation fading. All the TLDs of this group were exposed to a known amount of radiation from Cs-137 source. The 6 series composed of 5 TLDs were read out after 1,7,19,28,59, and 90 days. The above-mentioned procedures for obtaining pre-irradiation, and post-irradiation fading were performed for three storage temperatures (25°C, 4°C, and −18°C). Results: According to the results obtained in this study, in case of pre-irradiation fading study, the signal losses after 90 days are 12%, 24%, and 17% for 25°C, 4°C, and −18°C respectively. In case of post-irradiation fading study, the sensitivity losses after 90 days are 25%, 216%, and 20% for 25°C, 4°C, and −18°C respectively. Conclusion: The results indicate that the optimized time between exposing and reading out, and also the optimized time between annealing and exposing is 1 day.The reduction of Storage temperature will reduce the post-irradiation fading, While temperature reduction does not have any effect on pre-irradiation fading

Application of numerical analysis methods to thermoluminescence dosimetry; Aplicacion de metodos de analisis numerico a la dosimetria por termoluminiscencia

Energy Technology Data Exchange (ETDEWEB)

Gomez Ros, J M; Delgado, A

1989-07-01

This report presents the application of numerical methods to thermoluminescence dosimetry (TLD), showing the advantages obtained over conventional evaluation systems. Different configurations of the analysis method are presented to operate in specific dosimetric applications of TLD, such as environmental monitoring and mailed dosimetry systems for quality assurance in radiotherapy facilities. (Author) 10 refs.

The effectiveness of thermoluminescent crystals for calculation of required barrier against radiation at the diagnostic X-ray units

International Nuclear Information System (INIS)

Rahimi, Seyed Ali

2008-01-01

Concerning the importance of radiography techniques for diagnosis of disease and considering daily application and emerging new techniques in radiography from one hand and potential misuse of radiation and exposure to patients and personnel from other, it seems necessary the measure the amount of received radiation in current radiography procedures. The aim of this research is to determine the surface dose to patients in chest and skull radiography procedures in the hospitals of Mazandaran medical science university and compare those to given standards for such examinations from national and international recommendations. The study was based on the procedures, performed at six X-ray machines in six hospitals of the medical science university. Totally 120 patients with normal BMI, undergoing prescribed chest and skull examinations were involved. The exposure parameters, such as kVp - mAs product, film-screen combination and overall procedure setup at the all 6 X-ray machines were similar, thus provided unbiased evaluation of the surface dose. Surface dose was measured, using LiF thermoluminescent dosimeters (TLD). TLD after calibration was attached to the back and front skin surface of patients and after exposure TLD5 radiance was read with TLD reader. The average surface dose, measured for patients undergoing examinations of posterior - anterior view for pectoral, profile view for chest and posterior - anterior or anterior - posterior view of skull and profile view of skull where 0.51 , 3.36 , 7.25 and 7.59 mGy, respectively. These figures exceed recommended standards. To decrease patient surface dose, such measures, as periodic and continuous on-the-job education as well as supervision could increase technical and technological knowledge and rise awareness about radiation protection issues, thus improving the situation in hospitals. (author)

Analytical evaluation of dose measurement of critical accident at SILENE (Contract research)

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Takemi; Tonoike, Kotaro; Miyoshi, Yoshinori [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2003-03-01

Institute for Radioprotection and Nuclear Safety (IRSN) and the OECD Nuclear Energy Agency (NEA) jointly organized SILENE Accident Dosimetry Intercomparison Exercise to intercompare the dose measurement systems of participating countries. Each participating country carried out dose measurements in the same irradiation field, and the measurement results were mutually compared. The authors participated in the exercise to measure the doses of gamma rays and neutron from SILENE by using thermoluminescence dosimeters (TLD's) and an alanine dosimeter. In this examination, the authors derived evaluation formulae for obtaining a tissue-absorbed dose from measured value (ambient dose equivalent) of TLD for neutron. We reported the tissue-absorbed dose computed using this evaluation formula to OECD/NEA. TLD's for neutron were irradiated in the TRACY facility to verify the evaluation formulae. The results of TLD's were compared with the calculations of MCNP and measurements with alanine dose meter. We found that the ratio of the dose by the evaluation formula to the measured value by the alanine dosimeter was 0.94 and the formula agreed within 6%. From examination of this TRACY, we can conclude that the value reported to OECD/NEA has equivalent accuracy. (author)

Thermoluminescent dosemeter in a X-ray diffractometer

International Nuclear Information System (INIS)

Mendoza A, D.; Gonzalez M, P.; Falcon B, T.; Castano, V.M.

1999-01-01

In this work it was presented the results obtained of the dosimetry which was realized in a X-ray diffractometer for powders, trademark Siemens D5000, using the thermoluminescent signal generated by the X-rays in the commercial dosemeter TLD-100 of Harshaw, US. In according to the results obtained, the radiation quantity received by an analysed material in the diffractometer, will be proportional to exposure time and it can vary from unities until tenths of grays. These results are very outstanding when are analysed crystalline materials in a diffractometer, for knowing the present crystalline phases, mainly if these are highly sensitive to the ionizing radiation, as it is the case of the thermoluminescent materials. (Author)

Type tests to the automatic system of thermoluminescent dosimetry acquired by the CPHR for personnel dosimetry; Pruebas tipo al sistema de dosimetria termoluminiscente automatico adquirido por el CPHR para dosimetria personal

Energy Technology Data Exchange (ETDEWEB)

Molina P, D.; Pernas S, R. [Centro de Proteccion e Higiene de las Radiaciones (CPHR), Calle 20, No. 4113 e/ 41 y 47, Miramar, Ciudad de la Habana (Cuba)]. e-mail: daniel@cphr.edu.cu

2005-07-01

The CPHR individual monitoring service acquired an automatic RADOS TLD system to improve its capacities to satisfy the increasing needs of their national customers. The TLD system consists of: two automatic TLD reader, model DOSACUS, a TLD irradiator and personal dosimeters card including slide and holders. The dosimeters were composed by this personal dosimeters card and LiF: Mg,Cu,P (model GR-200) detectors. These readers provide to detectors a constant temperature readout cycle using hot nitrogen gas. In order to evaluate the performance characteristics of the system, different performance tests recommended by the IEC 1066 standard were carried out. Important dosimetric characteristics evaluated were batch homogeneity, reproducibility, detection threshold, energy dependence, residual signal and fading. The results of the tests showed good performance characteristics of the system. (Author)

QA/QC Program Developed For Environmental Monitoring In-House Applications Using TLDs

International Nuclear Information System (INIS)

Kamal, S.M.

2007-01-01

Thermoluminescent dosimetry (TLD) is widely used for environmental monitoring. Dosimetry measurements are an important component of the program and must be of high quality. To ensure accurate and reliable measurements, quality assurance/quality control (QNQC) procedures must be established, reviewed and followed. Dosimetry performance tests and Q A procedures are outlined in ANSI documents such as N/A, N.29 and N.37. The program includes calibration of the TLD reader (TLD-4000) using traceable radiation standards and annealing and sensitivity checks for the dosimeters. The operating parameters of TLD reader were controlled with internal checks creating constant measurement conditions. Overall system performance assessed using control dosimeters exposed to known amounts of radiation. This program led to improvements in the elements of TLD system (detector, reader and measurement cycle). Measurement cycle includes annealing, package and storage, irradiation, readout and mathematical evaluation. The main characteristics tested for TLDs are batch homogeneity, sensitivity, reproducibility, linearity, light sensitivity, fading and energy dependence. Thus, the influence of this program will be appeared in precision of dose assessment especially in low doses of environmental exposures

Establishment of Ge-doped optical fibres as thermoluminescence dosimeters for brachytherapy

Energy Technology Data Exchange (ETDEWEB)

Issa, Fatma, E-mail: f.issa@surrey.ac.uk [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Department of Radiotherapy, Tripoli Medical Centre (TMC), Tripoli (Libya); Abdul Rahman, A.T. [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); School of Physics and Material Studies, Faculty of Applied Sciences, Universiti Teknologi MARA Malaysia, Campus of Negeri Sembilan, 72000 Kuala Pilah (Malaysia); Hugtenburg, Richard P. [Department of Medical Physics and Clinical Engineering, Abertawe Bro Morgannwg UHB and School of Medicine, Swansea University, Swansea, SA2 8PP (United Kingdom); Bradley, David A. [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Department of Radiological Sciences, King Saud University, P.O. Box 10219, Riyadh 11432 (Saudi Arabia); Nisbet, Andrew [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Department of Medical Physics, Royal Surrey County Hospital NHS Foundation Trust, Guildford, GU2 7XX (United Kingdom)

2012-07-15

This study aims to establish the sensitive, {approx}120 {mu}m high spatial resolution, high dynamic range Ge-doped optical fibres as thermoluminescence (TL) dosimeters for brachytherapy dose distribution. This requires investigation to accommodate sensitivity of detection, both for the possibility of short range dose deposition from beta components as well as gamma/x-mediated dose. In-air measurements are made at distances close to radionuclide sources, evaluating the fall off in dose along the transverse axis of {sup 133}Ba and {sup 60}Co radioactive sources, at distances from 2 mm up to 20 mm from their midpoints. Measurements have been compared with Monte Carlo code DOSRZnrc simulations for photon-mediated dose only, agreement being obtained to within 3% and 1% for the {sup 133}Ba and {sup 60}Co sources, respectively. As such, in both cases it is determined that as intended, beta dose has been filtered out by source encapsulation. - Highlights: Black-Right-Pointing-Pointer We seek to establish Ge-doped optical fibres as TLDs for brachytherapy. Black-Right-Pointing-Pointer Dose was evaluated along the central axis of {sup 133}Ba and {sup 60}Co, at 2 mm-20 mm. Black-Right-Pointing-Pointer We verify values using DOSRZnrc Monte Carlo code simulations. Black-Right-Pointing-Pointer Good agreement is between dose measurements and calculation to within 3% and 1%. Black-Right-Pointing-Pointer Methodology is to be used in obtaining doses around {sup 125}I and {sup 192}Ir sources.

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

International Nuclear Information System (INIS)

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

1996-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-06-30

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

Values of dose and individual of a individual thermoluminescent dosimeter submitted to x and gamma radiations

International Nuclear Information System (INIS)

Moraes, Cassiana Viccari de; Pela, Carlos Alberto

2001-01-01

The individual monitoring provides information for the control of exposures, and estimates the dose received by individuals. This is an essential tool in personal dosimetry. It's based on a radiation protection concept, allowing an individual exposure control, besides guaranteeing that the dose restrictions will not be exceeded. Usually, the dose monitoring is performed by using an individual dosemeter placed on a representative position of the most exposed point on the thoracic surface. The dosemeter, which is analyzed in the present work, is made of three CaSO 4 -Dy thermoluminescent detectors, plastic filters, copper and copper-lead, mounted in an acrylic support. The dose received by on each detector, which forms the dosemeter, is related according to their energetic curve dependence. The dose amount is calculated from these curves by using an algorithm, and it was taken in to consideration the detector calibration and thermoluminescent responses, due to the x and g radiation exposure. That algorithm has the capacity to determine the energies that were irradiated the detector. Therefore, to aid the service in the moment of evaluate the dose received by the individual and where it is coming from. The algorithm has provided individual dose value H x , defined as operational quantity for photons adopted in the Brazilian Metric System. The algorithm can determine two dose values and such values have been analyzed according to the kind of irradiated energy on the dosimeter and it has shown that both values are within established limits by Instituto de Radioprotecao e Dosimetria (IRD). (author)

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

Thermoluminescent characteristics of LiF:Mg, Cu, P and CaSO_4:Dy for low dose measurement

International Nuclear Information System (INIS)

Del Sol Fernández, S.; García-Salcedo, R.; Mendoza, J. Guzmán; Sánchez-Guzmán, D.; Rodríguez, G. Ramírez; Gaona, E.; Montalvo, T. Rivera

2016-01-01

Thermoluminescence (TL) characteristics for LiF:Mg, Cu, P, and CaSO_4:Dy under the homogeneous field of X-ray beams of diagnostic irradiation and its verification using thermoluminescence dosimetry are presented. The irradiation were performed utilizing a conventional X-ray equipment installed at the Hospital Juárez Norte of México. Different thermoluminescence characteristics of two material were studied, such as batch homogeneity, glow curve, linearity, detection threshold, reproducibility, relative sensitivity and fading. Materials were calibrated in terms of absorbed dose to the standard calibration distance and they were positioned in a generic phantom. The dose analysis, verification and comparison with the measurements obtained by the TLD-100 were performed. Results indicate that the dosimetric peak appears at 202 °C and 277.5 °C for LiF:Mg, Cu, P and CaSO_4:Dy, respectively. TL response as a function of X-ray dose showed a linearity behavior in the very low dose range for all materials. However, the TLD-100 is not accurate for measurements below 4 mGy. CaSO_4:Dy is 80% more sensitive than TLD-100 and it show the lowest detection threshold, whereas LiF:Mg, Cu, P is 60% more sensitive than TLD-100. All materials showed very good repeatability. Fading for a period of one month at room temperature showed low fading LiF:Mg, Cu, P, medium and high for TLD-100 and CaSO_4:Dy. The results suggest that CaSO_4:Dy and LiF:Mg, Cu, P are suitable for measurements at low doses used in radiodiagnostic. - Highlights: • Several dosimetric characteristics were evaluated. • TL dose response to very low dose X-rays was studied. • The applications proposed for each material may be useful for diagnostic radiology dosimetry.

Reproducibility and calibration studies of TLD 600, TLD 700 and TLD 400

International Nuclear Information System (INIS)

Cavalieri, T.A.; Castro, V.A.; Siqueira, P.T.D.

2013-01-01

A new method to study of reproducibility of the thermoluminescent dosimeters (TLDs) and their calibration was carried on and compared with the method previously used by the BNCT research group of IPEN/CNEN. In this new method, aimed to identify the relations between the individual response of certain types of TLDs with their average response, it was observed a relation approximately constant even at different irradiations. From these relations, normalization of TLDs responses were made, and this method was compared with the method previously adopted by BNCT research group of IPEN/CNEN given better responses. With this new method, the dose response calibration o were made for two gamma sources, with different energies, 60 Co and 137 Cs, for doses ranging from 20 mGy to 1 Gy, and it has been possible to observe the response dependence of these TLDs on energy. (author)

Studies on dosimetric tests applying source irradiation force of Cs-137 for using in chambers for calibration and TLD type dosimeters

International Nuclear Information System (INIS)

Ribeiro, Laila Lorena X.; Barbosa, Rugles Cesar; Correa, Rosangela S.

2011-01-01

The West Central region of Brazil does not have a basic infrastructure for research, development, training programs, and personnel dosimetry education. All of them applied to environmental, industrial and medical uses. Service deployment for irradiance of TLD, via 137 Cs irradiator J. L. SHEPHERD model 28-8A (444 activity GBq) in CRCN-CO, it is necessary to introduce procedures for calibration of the radiator and other procedures related to dosimetry and calibration. Such procedures should be repeated periodically, as necessary to introduce techniques that make the service of the CRCN-CO a template, and that meet all standards requirements for radioprotection and operation of dosimetry and calibration. The objective of this work was to evaluate the radiation field of Cs-137, and the automatic system which systematizes the calibration procedures attached to a system control target for the radiator/calibration of monitors, and portable dosimeters. (author)

Semi-empirical simulation of thermoluminescent response under different filter geometries

International Nuclear Information System (INIS)

Shammas, Gabriel Issa Jabra

2006-01-01

Many thermoluminescent materials has been developed and used for photon personal dosimetry but no one has all desired characteristics alone. These characteristics include robustness, high sensitivity, energy photon independence, large range of photon energy detection, good reproducibility, small fading and simple glow curve with peaks above 150 deg C. Calcium Sulfate Dysprosium doped (CaSO 4 :Dy) phosphor Thermoluminescent Dosimeter (TLD) has been used by many laboratories, mainly in Brazil and India. Another interesting phosphor is Calcium Fluoride (CaF 2 ). These phosphor advantages begin to be more required and its disadvantages have became more apparent, in a global market more and more competitive. These phosphors are used in environmental and area monitoring, once they present more sensibility than other phosphors, like LiF:Mg. Theirs mainly disadvantage is a strong energetic dependence response, which must be corrected for theirs application in the field, where photon radiation is unknown a priori. An interesting way do make this correction in orthogonal incidence of the radiation on the phosphor is to interject a plane leaked filter between the beam and the phosphor. In order to reduce the energetic dependence on any incidence angle, reducing the field dose measurement uncertainty too, this work presents a simulation study on spherical filter geometries. It was simulated photon irradiations with Gamma rays of 60 Co and x-rays of 33; 48 and 118 keV, on many incidence angles from zero to ninety degrees. These semi-empirical computational simulations using finite differences in three dimensions were done in spherical coordinates. The results pointed out the best filter thicknesses and widths, in order to optimize the correction on energetic dependence. (author)

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

International Nuclear Information System (INIS)

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

2003-01-01

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

Analysis of personnel monitoring control card data

International Nuclear Information System (INIS)

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

2018-01-01

In India, personnel monitoring of radiation workers for X-, beta- and gamma- radiation is carried out using a thermoluminescence dosemeter (TLD) system based on CaSO 4 :Dy Teflon TLD disc. A large number of radiation workers get very low occupational doses and their doses are reported as zero since it is not above detectable limits. Therefore, the detection of low levels of occupational dose over and above the natural background assumes great importance. In the present system, the estimation of the background dose is achieved by use of control dosemeters. An analysis of the readings of the control dosimeters sent to various institutions was carried out to arrive at conclusions regarding the validity of the use of control dosimeter

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.)

Dosimetric Characteristics of a LKB:Cu,Mg Solid Thermoluminescence Detector

International Nuclear Information System (INIS)

Alajerami Yasser Saleh Mustafa; Hashim Suhairul; Ramli Ahmad Termizi; Saleh Muneer Aziz; Kadir Ahmad Bazlie Bin Abdul; Saripan, Mohd. Iqbal

2013-01-01

We present the main thermoluminescence characteristics of a newly borate glass dosimeter modified with lithium and potassium carbonate (LKB) and co-doped with CuO and MgO. An enhancement of about three times has been shown with the increment of 0.1mol% MgO as a co-dopant impurity. The effects of dose linearity, storage capacity, effective atomic number and energy dose response are studied. The proposed dosimeter shows a simple glow curve, good linearity up to 10 3 Gy, close effective atomic number and photon energy independence. The current results suggest using the proposed dosimeter in different dosimetric applications

Energy absorption buildup factors for thermoluminescent dosimetric materials and their tissue equivalence

DEFF Research Database (Denmark)

Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif

2010-01-01

Gamma ray energy-absorption buildup factors were computed using the five-parameter geometric progression (G-P) fitting formula for seven thermoluminescent dosimetric (TLD) materials in the energy range 0.015-15 MeV, and for penetration depths up to 40 mfp (mean free path). The generated energy-absorption...

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.)

Thermoluminescent response of LiF before variation of the heating rate; Respuesta termoluminiscente de LiF ante variacion de la tasa de calentamiento

Energy Technology Data Exchange (ETDEWEB)

Barrios, R. [Facultad de Quimica, UAEM, 50000 Toluca, Estado de Mexico (Mexico); Avila, O. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

2003-07-01

Comparisons of glow curves of lithium fluoride dosemeters TLD-100 measured to two heating rates with the purpose of quantifying the change in the temperature of the peaks 5 and 7 for the thermoluminescent reader equipment Harshaw 4000 of the thermoluminescence laboratory of the ININ were carried out. (Author)

Production of thermoluminescent dosemeters based on MgB4O7: Dy and MgB4O7: Tm

International Nuclear Information System (INIS)

Souza, Luiza Freire de; Souza, Divanizia N.

2013-01-01

The thermoluminescent dosimetry (TL) is a well-established technique for the detection of ionizing radiation in hospitals, clinics, and industrial establishments where there is the need to quantify the radiation. For this practice is require the use phosphors which are sensitive to radiation. Some phosphors are already commonly used in this practice, for example, TLD-100 (LiF: Mg, Ti), CaSO 4 :Tm and CaSO 4 :Dy. A compound that was most recently introduced in dosimetry and has many advantageous features to detect neutrons, electrons and gamma is the magnesium tetraborate (MgB 4 O 7 ), but the undoped material is not good for dosimetry, since signal does not show satisfactory thermoluminescence. The present work presents the analysis of the compound MgB 4 O 7 when doped with rare earth elements, thulium (Tm) and dysprosium (Dy). The production of MgB 4 O 7 : Dy and MgB 4 O 7 : Tm occurred under acidic conditions. Following the process of crystal growth, several tests were made on phosphors produced to verify the quality of materials as TL dosimeter. Initially, was made the identification of the crystalline phases found in the material, using the technique of X-ray diffractometry, and then were evaluated and compared the TL emission curves of the crystals with two different types of dopants, to this, the samples were irradiated with different radiation sources: 137 Cs (0,66 MeV), 60 Co (1.25 MeV) and X-rays (0.41 MeV) and based on the results was evaluated the energy dependence of phosphors. Another characteristic analyzed, was the decay of TL signal for the material (fading). The results show that the material can be an excellent TL dosimeter when doped with rare earth elements Dy and Tm. (author)

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.

A study on the application of two-dosimeter algorithm to estimate the effective dose in an inhomogeneous radiation field at Korean Nuclear Power Plants

International Nuclear Information System (INIS)

Kim, Hee Geun; Kong, Tae Young

2008-01-01

In Korean Nuclear Power Plants (NPPs), two ThermoLuminescent Dosimeters (TLD) were provided to workers who work in an inhomogeneous radiation field; one on the chest and the other on the head. In this way, the effective dose for radiation workers at NPPs was determined by the high deep dose between two radiation dose from these TLDs. This represented a conservative method of evaluating the degree of exposure to radiation. In this study, to prevent the overestimation of the effective dose, field application experiments were implemented using two-dosimeter algorithms developed by several international institutes for the selection of an optimal algorithm. The algorithms used by the Canadian Ontario Power Generation (OPG) and American ANSI HPS N13.41, NCRP (55/50), NCRP (70/30), EPRI (NRC), Lakshmanan, and Kim (Texas A and M University) were extensively analyzed as two-dosimeter algorithms. In particular, three additional TLDs were provided to radiation workers who wore them on the head, chest, and back during maintenance periods, and the measured value were analyzed. The results found no significant differences among the calculated effective doses, apart from Lakshmanan's algorithm. Thus, this paper recommends the NCRP(55/50) algorithm as an optimal two-dosimeter algorithm in consideration of the solid technical background of NCRP and the convenience of radiation works. In addition, it was determined that a two-dosimeter is provided to a single task which is expected to produce a dose rate of more than 1 mSv/hr, a difference of dose rates depending on specific parts of the body of more than 30%, and an exposure dose of more than 2 mSv

Estimation of organ cumulated activities and absorbed doses on intakes of several 11C labelled radiopharmaceuticals from external measurement with thermoluminescent dosimeters.

Science.gov (United States)

Nakamura, T; Hayashi, Y; Watabe, H; Matsumoto, M; Horikawa, T; Fujiwara, T; Ito, M; Yanai, K

1998-02-01

We have developed a method for obtaining the cumulated activities in organs from radionuclides, which are injected into the patient in nuclear medicine procedures, by external exposure measurement with thermoluminescent dosimeters (TLDs) which are attached to the patient's body surface close to source organs to obtain information on body-surface doses. As the surface dose is connected to the cumulated activities in source organs through radiation transmission in the human body which can be estimated with the aid of a mathematical phantom, the organ cumulated activities can be obtained by the inverse transform method. The accuracy of this method was investigated by using a water phantom in which several gamma-ray volume sources of known activity were placed to simulate source organs. We then estimated by external measurements the organ cumulated activities and absorbed doses in subjects to whom the radiopharmaceuticals 11C-labelled Doxepin, 11C-labelled YM09151-2 and 11C-labelled Benzotropin were administered in clinical nuclear medicine procedures. The cumulated activities in the brain obtained with TLDs for Doxepin and YM09151-2 are 63.6 +/- 6.2 and 32.1 +/- 12.0 kBq h MBq-1 respectively, which are compared with the respective values of 33.3 +/- 9.9 and 23.9 +/- 6.2 kBq h MBq-1 with direct PET (positron emission tomography) measurements. The agreement between the two methods is within a factor of two. The effective doses of Doxepin, YM09151-2 and Benzotropin are determined as 6.92 x 10(-3), 7.08 x 10(-3) and 7.65 x 10(-3) mSv MBq-1 respectively with the TLD method. This method has great advantages, in that cumulated activities in several organs can be obtained easily with a single procedure, and the measurements of body surface doses are performed simultaneously with the nuclear medicine procedure, as TLDs are too small to interfere with other medical measurements.

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.)

Study of physical factors affecting the TLD readout

International Nuclear Information System (INIS)

Ahmed, Amira Abd Elrhman Ebrahim

2015-10-01

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

Biological and clinical dosimetry. Progress report July 1, 1964-June 30, 1979

International Nuclear Information System (INIS)

Laughlin, J.S.; McDonald, J.C.

1979-01-01

The dosimetric studies at this laboratory were initiated with the primary goal of developing systems for the determination of absorbed dose in biological research and clinical applications. The primary method under study is the local absorbed dose calorimeter, a concept initiated and developed by J. S. Laughlin. In addition, secondary dosimetric systems such as ionization chambers, chemical dosimeters and thermoluminescent dosimeters (TLD) are being developed and applied to provide an absolute basis for the evaluation and comparison of experiments, treatments, and other procedures using radiation

Investigation and measurement of radio thermoluminescence properties of some calci tic mollusc shells of the Persian Gulf and the Oman Sea (for γ radiation dosimetry)

International Nuclear Information System (INIS)

Ghafourian, H.; Rabbani, M.; Rouhi, U.

2000-01-01

Biogenic Calcium Carbonate, particularly as naturally thermoluminescent calci tic mollusc shells may serve as excellent radio thermoluminescent dosimeters. In this study the radio thermoluminescence properties of 8 different bivalves of the Persian Gulf, the Oman Sea and the internal calcite shell of Sepia sp. are investigated. The results of this investigation have shown that the shells of Sepia sp., Pinctata radiata and Card ita bicolor as appropriate dosimeters for both personal and industrial dosimetry purposes, among which Sepia sp. is the most sensitive one. Callista umbonella and Mactra sp. are relatively less thermoluminescent while Saccostrea Cucullata and Chlamys ruschenbergerii are completely inert with respect to γ - thermoluminescence. Thermoluminescence properties of Anadara refescens and Anadara secticostata decrease surprisingly by an increase in the absorbed dose of γ radiation, which can mainly be interpreted as the result of crystal lattice destruction caused by ionizing radiation

Radiation protection in medicine (542) comparison of different dosimetry systems for dose measurements in diagnostic radiology

International Nuclear Information System (INIS)

Milkovic, D.; Ranogajec-Komor, M.; Miljanic, S.; Knezevic, Z.; Krpan, K.

2006-01-01

The dose measurement on patients in X-ray diagnostic is not simple, because low doses with low and various energies have to be measured. The aim of this preliminary study was to compare high sensitivity thermoluminescent dosimeter (T.L.D.) (LiF:Mg,Cu,P) and radio-photoluminescent (R.P.L.) glass dosimeters for dose measurements in routine X-ray diagnostic of chest of children. The energy dependence of the dosimeters was investigated in Secondary Standard Dosimetry Laboratory (SSDL). The energy range was 33- 65 keV mean energy, the dosimeters were placed free in air and on the water phantom. The results were compared to calculated values of Hp(10). The next step was the irradiation in a routine X-ray diagnostic unit. Irradiations were performed by the Shimadzu X-ray unit. The selected irradiation conditions were the same as that most commonly used for baby examinations. Doses were measured with dosimeters placed free-in-air and also with the dosimeters placed on the water phantom and baby phantom. The results show that the R.P.L. glass dosimeters and LiF:Mg,Cu,P based T.L.D. are suitable for low dose measurements in X-ray diagnostic. The uncertainty of dose determination is mainly caused by the energy dependence of dosimeters. (authors)

Neutron field characterization in the installation for BNCT study in the IEA-R1 reactor; Caracterizacao do campo de neutrons na instalacao para estudo em BNCT no reator IEA-R1

Energy Technology Data Exchange (ETDEWEB)

Carneiro Junior, Valdeci

2008-07-01

This work aims to characterize the mixed neutron and gamma field, in the sample irradiation position, in a research installation for Boron Neutron Capture Therapy (BNCT), in the IPEN IEA-R1 reactor. The BNCT technique has been studied as a safe and selective option in the treatment of resistant cancerigenous tumors or considered non-curable by the conventional techniques, for example, the Glioblastoma Multiform - a brain cancerigenous tumor. Neutron flux measurements were carried out: thermal, resonance and fast, as well as neutron and gamma rays doses, in the sample position, using activation foils detectors and thermoluminescent dosimeters. For the determination of the neutron spectrum and intensity, a set of different threshold activation foils and gold foils covered and uncovered with cadmium irradiated in the installation was used, analyzed by a high Pure Germanium semiconductor detector, coupled to an electronic system suitable for gamma spectrometry. The results were processed with the SAND-BP code. The doses due to gamma and neutron rays were determined using thermoluminescent dosimeters TLD 400 and TLD 700 sensitive to gamma and TLD 600, sensitive to neutrons. The TLDs were selected and used for obtaining the calibration curves - dosimeter answer versus dose - from each of the TLD three types, which were necessary to calculate the doses due to neutron and gamma, in the sample position. The radiation field, in the sample irradiation position, was characterized flux for thermal neutrons of 1.39.10{sup 8} {+-} 0,12.10{sup 8} n/cm{sup 2}s the doses due to thermal neutrons are three times higher than those due to gamma radiation and confirm the reproducibility and consistency of the experimental findings obtained. Considering these results, the neutron field and gamma radiation showed to be appropriated for research in BNCT. (author)

Neutron field characterization in the installation for BNCT study in the IEA-R1 reactor

International Nuclear Information System (INIS)

Carneiro Junior, Valdeci

2008-01-01

This work aims to characterize the mixed neutron and gamma field, in the sample irradiation position, in a research installation for Boron Neutron Capture Therapy (BNCT), in the IPEN IEA-R1 reactor. The BNCT technique has been studied as a safe and selective option in the treatment of resistant cancerigenous tumors or considered non-curable by the conventional techniques, for example, the Glioblastoma Multiform - a brain cancerigenous tumor. Neutron flux measurements were carried out: thermal, resonance and fast, as well as neutron and gamma rays doses, in the sample position, using activation foils detectors and thermoluminescent dosimeters. For the determination of the neutron spectrum and intensity, a set of different threshold activation foils and gold foils covered and uncovered with cadmium irradiated in the installation was used, analyzed by a high Pure Germanium semiconductor detector, coupled to an electronic system suitable for gamma spectrometry. The results were processed with the SAND-BP code. The doses due to gamma and neutron rays were determined using thermoluminescent dosimeters TLD 400 and TLD 700 sensitive to gamma and TLD 600, sensitive to neutrons. The TLDs were selected and used for obtaining the calibration curves - dosimeter answer versus dose - from each of the TLD three types, which were necessary to calculate the doses due to neutron and gamma, in the sample position. The radiation field, in the sample irradiation position, was characterized flux for thermal neutrons of 1.39.10 8 ± 0,12.10 8 n/cm 2 s the doses due to thermal neutrons are three times higher than those due to gamma radiation and confirm the reproducibility and consistency of the experimental findings obtained. Considering these results, the neutron field and gamma radiation showed to be appropriated for research in BNCT. (author)

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

International Nuclear Information System (INIS)

Saez Vergara, J.C.

1990-01-01

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

Thermoluminescent dose measurements on board Salyut type orbital stations

International Nuclear Information System (INIS)

Akatov, Yu.A.; Arkhangelskij, V.V.; Aleksandrov, A.P.

1984-06-01

A small, vibration- and shock-resistant thermoluminescent dosemeter (TLD) system - named PILLE - was developed for orbital stations at the Central Research Institute for Physics, Hungary, to measure the cosmic radiation dose on-board. The first on-board measurements with this system were performed by B. Farkas, the Hungarian astronaut, on the Salyut-6 space station in 1980. The same instrument was used by other crews in the following years. Doses measured at different sites in Salyut-6 are presented. The dose rates varied from 0.7 to 0.11 mGy.day -1 . After the first cosmic measurements, the system was further developed. The minimum detectable dose of the new TLD system is 1 μGy, i.e. less by one order of magnitude than that of the former system. The self-irradiation dose rate of the TLD bulbs is also reduced by more than an order of magnitude to 10 nGy.h -1 , by use of potassium-free glass for the bulb envelope. This new type of PILLE TLD system is currently on-board Salyut-7. The dose rates (0.12-0.23 mGy.day -1 ) measured in 1983 are presented in detail. (author)

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

Energy Technology Data Exchange (ETDEWEB)

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

1990-09-01

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

ESR/Alanine {gamma}-dosimetry in the 10-30 Gy range

Energy Technology Data Exchange (ETDEWEB)

Fainstein, C. E-mail: cfainstein@cab.cnea.gov.ar; Winkler, E.; Saravi, M

2000-05-15

We report Alanine Dosimeter preparation, procedures for using the ESR/Dosimetry method, and the resulting calibration curve for {gamma}-irradiation in the range from 10-30 Gy. We use calibration curve to measure the irradiation dose in {gamma}-irradiation of human blood, as required in Blood Transfusion Therapy. The ESR/Alanine results are compared against those obtained using the thermoluminescent dosimetry (TLD) method.

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

Comparing of the yield curve of the pediatric X-ray equipment using thermoluminescent dosimeters and cylindrical ionization chamber; Comparacao da curva de rendimento de um aparelho de raios X pediatrico utilizando dosimetros termoluminescentes e camara de ionizacao cilindrica

Energy Technology Data Exchange (ETDEWEB)

Filipov, Danielle, E-mail: dfilipov@utfpr.edu.br [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Schelin, Hugo R., E-mail: ledesmaiorgealberto@gmail.com [Instituto de Pesquisa Pele Pequeno Principe, Curitiba, PR (Brazil); Tilly Junior, Joao G., E-mail: joao.tilly@derax.com.br [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Hospital de Clinicas

2014-07-01

The determination of the yield curve of a radiographic equipment should be realized once a year, or when the unit be serviced. Besides being a requirement of ANVISA, through this test is possible to determine the incident air kerma (at a given point in the center of the beam) - INAK. Based on these concepts, the main objective of this work is the comparison of yield curves of the pediatric X-ray apparatus using two different detectors: one cylindrical ionization chamber and thermoluminescent dosimeters type LiF: Mg, Cu, P, as per protocol RLA / 9/057 IAEA. Then the equation of the yield curve (generated by each detector) was used to determine the INAK of 10 pediatric examinations, performed on this equipment. After the process of calibration of both detectors, they were placed side by side at a focus of the tube equipment for determining the performance of the same curve. Finally, using the curves generated by two detectors, INAK values of the 10 tests were calculated (from the kVp values, and mAs focus-patient of each exams), generating difference values at most 5%. As a conclusion, it can be said that the TLD lithium fluoride doped with Mg, Cu and P and the cylindrical ionization chambers may be used satisfactorily to determine the yield curve, whether as quality control or dosimetry.

Estimation of organ cumulated activities and absorbed doses on intakes of several {sup 11}C labelled radiopharmaceuticals from external measurement with thermoluminescent dosimeters

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Takashi; Hayashi, Yoshiharu; Watabe, Hiroshi; Matsumoto, Masaki; Horikawa, Tohru; Fujiwara, Takehiko; Ito, Masatoshi; Yanai, Kazuhiko [Cyclotron and Radioisotope Center, Tohoku University, Aoba, Aramaki, Sendai 980-77 (Japan)

1998-02-01

We have developed a method for obtaining the cumulated activities in organs from radionuclides, which are injected into the patient in nuclear medicine procedures, by external exposure measurement with thermoluminescent dosimeters (TLDs) which are attached to the patient's body surface close to source organs to obtain information on body-surface doses. As the surface dose is connected to the cumulated activities in source organs through radiation transmission in the human body which can be estimated with the aid of a mathematical phantom, the organ cumulated activities can be obtained by the inverse transform method. The accuracy of this method was investigated by using a water phantom in which several gamma-ray volume sources of known activity were placed to simulate source organs. We then estimated by external measurements the organ cumulated activities and absorbed doses in subjects to whom the radiopharmaceuticals {sup 11}C-labelled Doxepin, {sup 11}C-labelled YM09151-2 and {sup 11}C-labelled Benzotropin were administered in clinical nuclear medicine procedures. The cumulated activities in the brain obtained with TLDs for Doxepin and YM09151-2 are 63.6{+-}6.2 and 32.1{+-}12.0 kBq h MBq{sup -1} respectively, which are compared with the respective values of 33.3{+-}9.9 and 23.9{+-}6.2 kBq h MBq{sup -1} with direct PET (positron emission tomography) measurements. The agreement between the two methods is within a factor of two. The effective doses of Doxepin, YM09151-2 and Benzotropin are determined as 6.92x10{sup -3}, 7.08x10{sup -3} and 7.65x10{sup -3} mSv MBq{sup -1} respectively with the TLD method. This method has great advantages, in that cumulated activities in several organs can be obtained easily with a single procedure, and the measurements of body surface doses are performed simultaneously with the nuclear medicine procedure, as TLDs are too small to interfere with other medical measurements. (author)

Measurement of Gamma Knife registered helmet factors using MOSFETs

International Nuclear Information System (INIS)

Kurjewicz, Laryssa; Berndt, Anita

2007-01-01

The relative dose rate for the different Gamma Knife registered helmets (4, 8, 14, and 18 mm) is characterized by their respective helmet factors. Since the plateau of the dose profile for the 4 mm helmet is at most 1 mm wide, detector choices are limited. Traditionally helmet factors have been measured using 1x1x1 mm 3 thermoluminescent dosimeters (TLDs). However, these are time-consuming, cumbersome measurements. This article investigates the use of metal-oxide-semiconductor field effect transistors (MOSFETs) (active area of 0.2x0.2 mm 2 ) as a more accurate and convenient dosimeter. Their suitability for these measurements was confirmed by basic characterization measurements. Helmet factors were measured using both MOSFETs and the established TLD approach. A custom MOSFET cassette was designed in analogy to the Elekta TLD cassette (Elekta Instruments AB) for use with the Elekta dosimetry sphere. Although both dosimeters provided values within 3% of the manufacturer's suggestion, MOSFETs provided superior accuracy and precision, in a fraction of the time required for the TLD measurements. Thus, MOSFETs proved to be a reasonable alternative to TLDs for performing helmet factor measurements

Detection of ionizing radiations by studying ceramic tiles materials using thermoluminescence technique

Science.gov (United States)

Mandavia, H. C.; Murthy, K. V. R.; Purohit, R. U.

2017-05-01

Natural background radiation comes from two primary sources: cosmic radiation and terrestrial sources. Our natural environment has both livings and non-livings like - Sun, Moon, Sky, Air, Water, Soil, Rivers, Mountains, Forests, besides plants and animals. The worldwide average background dose for a human being is about 2.4 millisievert (mSv) per year. This exposure is mostly from cosmic radiation and natural radionuclides in the environment. The Earth, and all living things on it, are constantly bombarded by radiation from outer space. This radiation primarily consists of positively charged ions from protons to iron and larger nuclei derived sources outside our solar system. This radiation interacts with atoms in the atmosphere to create secondary radiation, including X-rays, muons, protons, alpha particles, pions, electrons, and neutrons. The present study discusses the utility of ceramic tiles as radiation dosimeters in case of nuclear fallout. Many flooring materials most of them are in natural form are used to manufacture floor tiles for household flooring purpose. Many natural minerals are used as the raw materials required for the manufacturing ceramic ware. The following minerals are used to manufacturing the ceramic tiles i.e. Quartz, Feldspar, Zircon, Talc, Grog, Alumina oxide, etc. Most of the minerals are from Indian mines of Gujarat and Rajasthan states, some of are imported from Russian subcontinent. The present paper reports the thermoluminescence dosimetry Study of Feldspar and Quartz minerals collected from the ceramic tiles manufacturing unit, Morbi. The main basis in the Thermoluminescence Dosimetry (TLD) is that TL output is directly proportional to the radiation dose received by the phosphor and hence provides the means of estimating unknown radiations from environment.

Measuring the absorbed dose in critical organs during low rate dose brachytherapy with 137 Cs using thermoluminescent dosemeters

International Nuclear Information System (INIS)

Torres, A.; Gonzalez, P.R.; Furetta, C.; Azorin, J.; Andres, U.; Mendez, G.

2003-01-01

Intracavitary Brachytherapy is one of the most used methods for the treatment of the cervical-uterine cancer. This treatment consists in the insertion of low rate dose 137 Cs sources into the patient. The most used system for the treatment dose planning is that of Manchester. This planning is based on sources, which are considered fixed during the treatment. However, the experience has shown that, during the treatment, the sources could be displaced from its initial position, changing the dose from that previously prescribed. For this reason, it is necessary to make measurements of the absorbed dose to the surrounding organs (mainly bladder and rectum). This paper presents the results of measuring the absorbed dose using home-made LiF: Mg, Cu, P + Ptfe thermoluminescent dosimeters (TLD). Measurements were carried out in-vivo during 20 minutes at the beginning and at the end of the treatments. Results showed that the absorbed dose to the critical organs vary significantly due to the movement of the patient during the treatment. (Author)

Blind test results - measure of incessant progress in personnel monitoring services at Kudankulam Nuclear Power Project

International Nuclear Information System (INIS)

Jashi, K.B.; Ashok Kumar, A.; Pandaram, P.

2018-01-01

Personnel Monitoring Services (PMS) at Thermoluminescent Dosimeter (TLD) laboratory, Kudankulam Nuclear Power Project (KKNPP) involve monitoring of about 1500 radiation workers of KKNPP for external radiation exposure on monthly basis. Quality assurance in PMS provides an overall estimate of accuracy which depends not only upon the dosimeter quality and reader performance but also on data interpretation, applicable software and the system. Therefore it measures the effectiveness of quality control mechanism. Blind test is an effective tool to check the performance of the processor without their knowledge during routine processing of the service cards

Radiation Exposure Reduction to Brachytherapy Staff By Using Remote Afterloading

International Nuclear Information System (INIS)

Attalla, E.M.

2005-01-01

The radiation exposures to the personnel staff from patients with brachytherapy implants in a brachytherapy service were reviewed. Exposures to the brachytherapy personnel, as determined by Thermoluminescence Dosimeter (TLD) monitors, indicates a four-fold reduction in exposures after the implantation of the use of remote afterloading devices. Quarterly TLD monitor data for seven quarters prior to the use of remote afterloading devices demonstrate an average projected annual dose equivalent to the brachytherapy staff of 2543 Μ Sv. After the implantation of the remote afterloading devices, the quarterly TLD monitor data indicate an average dose equivalent per person of 153 Μ Sv. This is 76% reduction in exposure to brachytherapy personnel with the use of these devices

Characterization of the personal thermoluminescent dosemeter of LiF: Mg, Ti + Ptfe

International Nuclear Information System (INIS)

Azorin N, J.; Gutierrez C, A.; Gonzalez M, P.

1991-01-01

The objective of this work is to characterize the thermoluminescent dosemeters taken place in the laboratory in form of pellets of LiF: Mg, Ti + Ptfe like personal dosemeters, subjecting them to the operation tests proposed by the international standards and comparing them with the TLD-100, the Tl dosemeter more used at the moment for personal dosimetry

Diffusion from a Ground Level Point Source Experiment with Thermoluminescence Dosimeters and Kr 85 as Tracer Substance

Energy Technology Data Exchange (ETDEWEB)

Gyllander, Ch; Hollman, S; Widemo, U

1969-04-15

Within the framework of the IRIS-project (Iodine Research in Safety Project) an experiment to study diffusion at near-ground level was carried out on 19 December 1967 using {sup 85}Kr as the tracer element. The object of the experiment was a) to test the method using |3-sensitive thermoluminescence dosimeters under actual field conditions. b) to study the initial dilution from a ground level point source. The test area chosen was the Tranvik valley just south of Trobbofjaerden, an inland bay of the Baltic. Dose distributions have been studied at two sections, 50 and 200 m respectively, from the release point. At each level various dispersion parameters have been experimentally determined and their conformity to normal distribution have been calculated. Dilution factors valid for the centre of the plume are related to the values reported in the literature. The experiment was made under ideal weather conditions above snow-free ground. Results of the next experiment, a point release at ground level from a building at Studsvik, are expected to yield valuable information concerning the effect of buildings on the diffusion pattern.

Diffusion from a Ground Level Point Source Experiment with Thermoluminescence Dosimeters and Kr 85 as Tracer Substance

International Nuclear Information System (INIS)

Gyllander, Ch.; Hollman, S.; Widemo, U.

1969-04-01

Within the framework of the IRIS-project (Iodine Research in Safety Project) an experiment to study diffusion at near-ground level was carried out on 19 December 1967 using 85 Kr as the tracer element. The object of the experiment was a) to test the method using |3-sensitive thermoluminescence dosimeters under actual field conditions. b) to study the initial dilution from a ground level point source. The test area chosen was the Tranvik valley just south of Trobbofjaerden, an inland bay of the Baltic. Dose distributions have been studied at two sections, 50 and 200 m respectively, from the release point. At each level various dispersion parameters have been experimentally determined and their conformity to normal distribution have been calculated. Dilution factors valid for the centre of the plume are related to the values reported in the literature. The experiment was made under ideal weather conditions above snow-free ground. Results of the next experiment, a point release at ground level from a building at Studsvik, are expected to yield valuable information concerning the effect of buildings on the diffusion pattern

Radiation doses measured by TLD (thermoluminescent dosimeter) in x-ray examination, especially on the skin area beneath of which female gonads situate

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, S; Hiraki, M; Murakami, S; Nishikawa, N; Yagi, T [Nissei Hospital, Osaka (Japan)

1977-03-01

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

Dosimetric properties of dysprosium doped calcium magnesium borate glass subjected to Co-60 gamma ray

Energy Technology Data Exchange (ETDEWEB)

Omar, R. S., E-mail: ratnasuffhiyanni@gmail.com; Wagiran, H., E-mail: husin@utm.my; Saeed, M. A. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru (Malaysia)

2016-01-22

Thermoluminescence (TL) dosimetric properties of dysprosium doped calcium magnesium borate (CMB:Dy) glass are presented. This study is deemed to understand the application of calcium as the modifier in magnesium borate glass with the presence of dysprosium as the activator to be performed as TL dosimeter (TLD). The study provides fundamental knowledge of a glass system that may lead to perform new TL glass dosimetry application in future research. Calcium magnesium borate glass systems of (70-y) B{sub 2}O{sub 3} − 20 CaO – 10 MgO-(y) Dy{sub 2}O{sub 3} with 0.05  mol % ≤ y ≤ 0.7  mol % of dyprosium were prepared by melt-quenching technique. The amorphous structure and TL properties of the prepared samples were determined using powder X-ray diffraction (XRD) and TL reader; model Harshaw 4500 respectively. The samples were irradiated to Co-60 gamma source at a dose of 50 Gy. Dosimetric properties such as annealing procedure, time temperature profile (TTP) setting, optimization of Dy{sub 2}O{sub 3} concentration of 0.5 mol % were determined for thermoluminescence dosimeter (TLD) reader used.

Comparative study of different Al_2O_3:C dosimeters using OSL technique for dosimetry on Volumetric Modulated Arc Radiotherapy Treatment (VMAT)

International Nuclear Information System (INIS)

Villani, Daniel; Campos, LetIcia L.; Mancini, Anselmo; Haddad, Cecilia M.K.

2016-01-01

In modern radiotherapy, the VMAT technique has become a successful treatment alternative. Due to its complexity, a quality assurance program must be established by evaluating, among other items, the dosimetric factors. This paper aims to compare the performance between the OSL aluminum oxide (Al_2O_3:C) nanoDot™ dosimeters (Inlight™ system) manufactured by Landauer Inc. and TLD-500 Al_2O_3:C dosimeters manufactured by Rexon™ for VMAT dosimetry using an anthropomorphic phantom. The results showed that both type of Al_2O_3:C dosimeters presented good repeatability and agreement between the doses measured and calculated by planning system. However, the need of sophisticated readers to OSL analysis of the TLD-500, turns it less practical for routine usage, comparing to Inlight™ system. (author)

External dosimetry by Thermoluminescent Dosimetry Laboratory - IPEN/CNEN - Brazil

International Nuclear Information System (INIS)

Manzoli, Jose Eduardo; Carvalho, Ricardo Nunes

2001-01-01

The Thermoluminescence Dosimetry Laboratory, LDT - IPEN/CNEN - Brazil, executes around six thousand TLD readings monthly. It is responsible for the dose evaluation and registration and for all the manufacture process of preparation and sending the dosemeters which are used by IPEN itself, hospitals, industries, town halls, universities, etc. Although prepared to read many kinds of materials, actually the LDT reads only CaSO 4 :Dy detector chips. Chips, heating molds, plastic packaging and almost every material or instrument are made right here at IPEN. The readings are performed in a Bicron Harshaw TLD model 5500, but an old model 2000-AB is ready to be used if necessary. In this work it is presented some features of this important service realized to the IPEN workers and to the community. (author)

External radiation surveillance

Energy Technology Data Exchange (ETDEWEB)

Antonio, E.J.

1995-06-01

This section of the 1994 Hanford Site Environmental Report describes how external radiation was measured, how surveys were performed, and the results of these measurements and surveys. External radiation exposure rates were measured at locations on and off the Hanford Site using thermoluminescent dosimeters (TLD). External radiation and contamination surveys were also performed with portable radiation survey instruments at locations on and around the Hanford Site.

External radiation surveillance

International Nuclear Information System (INIS)

Antonio, E.J.

1995-01-01

This section of the 1994 Hanford Site Environmental Report describes how external radiation was measured, how surveys were performed, and the results of these measurements and surveys. External radiation exposure rates were measured at locations on and off the Hanford Site using thermoluminescent dosimeters (TLD). External radiation and contamination surveys were also performed with portable radiation survey instruments at locations on and around the Hanford Site

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

Analyses of superficial and depth doses in intraoral radiology

Energy Technology Data Exchange (ETDEWEB)

Silva Santos de Oliveira, C.; Morais, R.P. de; Nascimento Souza, D. do [Universidade Federal de Sergipe - CCET - Dept. de Fisica, Sao Cristovao, SE (Brazil)

2006-07-01

In this work dosimetric analysis using thermoluminescence technique to study the beams characteristics of x-rays employed in dental radiology has been carried out. The obtained results with CaSO{sub 4}:Dy thermoluminescent dosimeters (TLD) were compared to the doses obtained with parallel-plates ionization chamber. Dosimetric evaluations were also done using radiographic films of large dimensions. The x-rays equipments analyzed were installed in the radiological services of Odontology Department of Sergipe Federal University (U.F.S.). Depending on the anatomical region to be examined the proper exposure time was select, for a fix voltage of 70 kV. The results with TLD and ionization chamber have been determined to female and male individuals. The intraoral regions analysed were the peri apical of the incisors, molar and pre-molar teeth and the occlusive region. These regions were simulated using acrylic plates absorbers installed on the film packet holder. The evaluation of the depth doses in the intraoral tissue was obtained using different acrylic plate thickness. The air kerma values have been evaluated with the ionization chamber located in the dental cone exit of the x-rays equipments. The integrated areas of the thermoluminescent glow curves showed coherent values when compared to the ones obtained with the ionization chamber and both methods presented a linear dependence with the exposition time. The analyses with films have allowed the evaluation of the beam scattering in the simulator apparatus. The studies had proven that the analysis of superficial dose and in depth used in dental radiology can be carried with thermoluminescent dosimeters. (authors)

Analyses of superficial and depth doses in intraoral radiology

International Nuclear Information System (INIS)

Silva Santos de Oliveira, C.; Morais, R.P. de; Nascimento Souza, D. do

2006-01-01

In this work dosimetric analysis using thermoluminescence technique to study the beams characteristics of x-rays employed in dental radiology has been carried out. The obtained results with CaSO 4 :Dy thermoluminescent dosimeters (TLD) were compared to the doses obtained with parallel-plates ionization chamber. Dosimetric evaluations were also done using radiographic films of large dimensions. The x-rays equipments analyzed were installed in the radiological services of Odontology Department of Sergipe Federal University (U.F.S.). Depending on the anatomical region to be examined the proper exposure time was select, for a fix voltage of 70 kV. The results with TLD and ionization chamber have been determined to female and male individuals. The intraoral regions analysed were the peri apical of the incisors, molar and pre-molar teeth and the occlusive region. These regions were simulated using acrylic plates absorbers installed on the film packet holder. The evaluation of the depth doses in the intraoral tissue was obtained using different acrylic plate thickness. The air kerma values have been evaluated with the ionization chamber located in the dental cone exit of the x-rays equipments. The integrated areas of the thermoluminescent glow curves showed coherent values when compared to the ones obtained with the ionization chamber and both methods presented a linear dependence with the exposition time. The analyses with films have allowed the evaluation of the beam scattering in the simulator apparatus. The studies had proven that the analysis of superficial dose and in depth used in dental radiology can be carried with thermoluminescent dosimeters. (authors)

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2006-07-01

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

Combination TLD/TED dose assessment

International Nuclear Information System (INIS)

Parkhurst, M.A.

1992-11-01

During the early 1980s, an appraisal of dosimetry programs at US Department of Energy (DOE) facilities identified a significant weakness in dose assessment in fast neutron environments. Basing neutron dose equivalent on thermoluminescence dosimeters (TLDS) was not entirely satisfactory for environments that had not been well characterized. In most operational situations, the dosimeters overrespond to neutrons, and this overresponse could be further exaggerated with changes in the neutron quality factor (Q). Because TLDs are energy dependent with an excellent response to thermal and low-energy neutrons but a weak response to fast neutrons, calibrating the dosimetry system to account for mixed and moderated neutron energy fields is a difficult and seldom satisfactory exercise. To increase the detection of fast neutrons and help improve the accuracy of dose equivalent determinations, a combination dosimeter was developed using TLDs to detect thermal and low-energy neutrons and a track-etch detector (TED) to detect fast neutrons. By combining the albedo energy response function of the TLDs with the track detector elements, the dosimeter can nearly match the fluence-to-dose equivalent conversion curve. The polymer CR-39 has neutron detection characteristics superior to other materials tested. The CR-39 track detector is beta and gamma insensitive and does not require backscatter (albedo) from the body to detect the exposure. As part of DOE's Personnel Neutron and Upgrade Program, we have been developing a R-39 track detector over the past decade to address detection and measurement of fast neutrons. Using CR-39 TEDs in combination with TLDs will now allow us to detect the wide spectrum of occupational neutron energies and assign dose equivalents much more confidently

A technical study of TLD beta calibration factor for exposures to depleted uranium

International Nuclear Information System (INIS)

Ashley, J.C.; Turner, J.E.; McMahan, K.L.; Souleyrette, M.L.; Bogard, R.S.

1995-06-01

The beta calibration factor for converting light output (on reading a thermoluminescent dosimeter) to shallow dose equivalent has been reexamined through theoretical calculations and experimental measurements. The results support the previously determined value for contact with a depleted uranium slab but indicate that for many actual workplace situations, the contact value may be overly conservative

Environmental radiation studies relevant to thermoluminescence dating

International Nuclear Information System (INIS)

Murray, A.S.; Bowman, S.G.E.; Aitken, M.J.

1980-01-01

To determine the age of a potsherd by the thermoluminescence (TL) technique, one must have an accurate knowledge of the cosmic and environmental gamma dose rate in quartz. This is obtained by leaving a sensitive TL dosimeter buried as near as possible to the position from which the sherd was removed. The ratios of the response of a quartz-like dosimeter to those of CaF 2 and LiF have been measured. This experiment used a 1-m cube of concrete containing 3000 ppM of uranium and its daughters. Smaller, less active matrixes of 40 K and thorium and its daughters have also been constructed. A means of making direct dose-rate determinations when the site context remains but burial of a dosimeter is impractical was developed using a NaI(Tl) system. The equipment was field tested on approx. 40 Peruvian archaeological sites, and results are compared with CaF 2 measurements

Dosimertry characteristics and performance comparisons: Environmental radiophotoluminescent glass dosemeters versus thermoluminescent dosemeters

International Nuclear Information System (INIS)

Lee, J.H.; Lin, M.S.; Hsu, S.M.; Chen, I.J.; Chen, W.L.; Wang, C.F.

2009-01-01

This paper describes the dosimetry characteristic comparison of environmental radiophotoluminescent glass dosemeter (RPLGD) and thermoluminescent dosemeter (TLD) systems employed at the Institute of Nuclear Energy Research (INER, Taiwan). The luminescence centers of TLD disappeared by reading process, and repetition of measurement is impossible. RPLGDs can be repeatedly read and keep the luminescence centers for a long time. The RPLGD fading is about 1% within 30 days after being exposed to ionizing radiation. Environmental cumulative doses measured by a RPLGD and a TLD were compared at the same monitoring points of INER during two years. The sensitivity of TLD decreased with gradual loss due to fading at higher temperatures. The difference between results obtained by RPLGD and TLD is discussed mainly with respect to the dependence on the ambient temperature. In addition, this research also refers to the American National Standard Institute (ANSI) Draft Standard N13.29 (1996) to organize the environmental dosimetry performance tests of the INER's RPLGDs and the TLDs. The results mean that both kinds of dosemeters can meet the performance test criteria. An accreditation procedure for the institutes which provide the environmental dosimetry services in Taiwan was suggested based on the comparison results of these two dosimetry systems

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

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.

Thermoluminescent analyses of mean photon energy of a field

Energy Technology Data Exchange (ETDEWEB)

Cavalieri, T. A.; De Paiva, F.; Fonseca, G.; Dalledone S, P. de T.; Yoriyaz, H., E-mail: tassio.cavalieri@usp.br [Instituto de Pesquisas Energeticas e Nucleares / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil)

2014-08-15

Nowadays a common method of dosimetry is utilize the thermoluminescent dosimetry (TLD) of LiF, where for pure gamma field is typically used the LiF or CaF{sub 2} TLDs and for mixed neutron and gamma field dosimetry is used the pair TLD-600/TLD-700. The difference between these three LiF TLDs is the amount of isotope {sup 6}Li in their composition. The isotope {sup 6}Li has a great cross section for thermal neutrons, making the TLD-600 sensitive to thermal neutrons beyond the radiation gamma. Whereas the TLD-700 is considered sensitive only for radiation gamma. Some studies showed an energetic dependence of these TLDs for gammas rays. So the goal of this work was study these energetic dependence of TLDs from the angular coefficient of their response versus dose calibration curves when they were irradiated in four fields with photons of different energies: 43 keV, 662 keV, 1.2 MeV, 3 MeV. In order to create the calibration curves TLD, it was performed three irradiations with distinct exposure times for each photon energy. These studies showed a different angular coefficient to each curve; demonstrate the energetic dependence of these TLDs. By simulation with Monte Carlo based code, MCNP-5, it was observed the deposited photon dose due to different photons energies. From these simulations, it was also possible to observe a difference of dose deposition in TLDs when they were exposed to the same dose provided from different photons energies. These work showed the previously study of photon energetic dependence of LiF TLDs. (Author)