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

The neutron response of a 7 LiF thermoluminescent dosimeter incorporated in the UKAEA criticality dosimeter

International Nuclear Information System (INIS)

Eid, A.M.; Delafield, H.J.

1976-04-01

There are practical advantages in incorporating a 7 LiF thermoluminescent dosimeter (TLD) for the measurement of γ-ray dose, into the personnel criticality dosimeter. This paper investigated the corrections necessary for the inherent direct response of the TLD neutrons, and its enhanced indirect response from prompt γ-rays resulting from neutron interactions with the metallic foils contained in the criticality dosimeter. The response of the TLD to fast fission neutrons was measured to be 0.02 γ rad/n rad. The indirect response of the TLD to thermal neutrons was measured to be 4.8 x 10 -10 rad n -1 cm 2 for dosimeters exposed in free air, and 7 x 10 -10 rad n -1 cm 2 for dosimeters worn on the body respectively. Application of these correction factors to TLD measurements made at International Dosimetry Intercomparisons (sponsored by the I.A.E.A.) gave improved agreement with the values given by other participants. (author)

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)

Personnel neutron dosimeter for use in a plutonium processing plant

International Nuclear Information System (INIS)

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

1978-01-01

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

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

Role of gel dosimeters in boron neutron capture therapy

International Nuclear Information System (INIS)

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

2015-01-01

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

Development of real time personal neutron dosimeter with two silicon detectors

Energy Technology Data Exchange (ETDEWEB)

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

1992-07-01

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

Response characteristics of selected personnel neutron dosimeters

International Nuclear Information System (INIS)

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

1983-09-01

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

Silicon Diode Dosimeter for Fast Neutrons

International Nuclear Information System (INIS)

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

1968-11-01

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

Silicon Diode Dosimeter for Fast Neutrons

Energy Technology Data Exchange (ETDEWEB)

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

1968-11-15

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

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)

Fast neutron dosimeter with wide base silicon diode

International Nuclear Information System (INIS)

Ma Lu

1986-01-01

This paper briefly introduces a wide base silicon diode fast neutron dosimeter with wide measuring range and good energy response to fast neutron. It is suitable to be used to detect fast neutrons in the mixed field of γ-ray, thermal neutrons and fast neutrons

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

International Nuclear Information System (INIS)

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

2010-01-01

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

Research on the formula of radiochromic film dosimeters

International Nuclear Information System (INIS)

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

2006-10-01

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

Design characteristics of a three-component AEOI Neutriran Albedo Neutron Personnel Dosimeter

International Nuclear Information System (INIS)

Sohrabi, M.; Katouzi, M.

1991-01-01

In establishing a national personnel neutron dosimetry service in Iran, different parameters of the AEOI Neutriran Albedo Neutron Personnel Dosimeter (NANPD) have been optimized. A NANPD was designed with three dosimetry components to measure (a) direct thermal neutrons, (b) direct fast neutrons and (C) direct neutrons by the detection of the albedo neutrons reflected from the body. The dosimeter consists of one or more Lexan polycarbonate and/or CR-39 foils and two 10 B (n,α) 7 Li converters in a cadmium cover so arranged as to efficiently measure the three neutron dose components separately. The boron converter thickness, its position relative to the beam direction and its distance from the PC foil were studied and the results were incorporated into the design. The dose response of the dosimeter, its lower detection limit as well as the correction factors related to the field neutrons and albedo neutrons were also determined for a 238 Pu-Be, an 241 Am-Be and a 252 Cf sources. In this paper, the dosimeter design and its dosimetric characteristics are presented and discussed. (author)

Angular dependence of dose equivalent response of an albedo neutron dosimeter

International Nuclear Information System (INIS)

Torres, B.A.; Boswell, E.; Schwartz, R.B.

1994-01-01

The ANSI provides procedures for testing the performance of dosimetry services. Although neutron dose equivalent angular response studies are not now mandated, future standards may well require that such studies be performed. Current studies with an albedo dosimeter will yield information regarding the angular dependence of dose equivalent response for this type of personnel dosimeter. Preliminary data for bare 252 Cf fluences show a marked decrease in dosimeter reading with increasing angle. The response decreased by an approximate factor of four. For the horizontal orientation, the same response was noted from both positive and negative angles. However, for the vertical orientation, the response was unexplainably assymetric. We are also examining the response of the personnel badge in moderated 252 Cf fluences. Responses from the moderated and unmoderated 252 Cf fields and theoretical calculations of the neutron angular response will be compared. This information will assist in building a data base for future comparisons of neutron angular responses with other neutron albedo dosimeters and phantoms

Investigations of CR39 dosimeters for neutron routine dosimetry

International Nuclear Information System (INIS)

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

2004-01-01

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

Investigating On Colour Stability Conditions Of Postirradiation Radiochromic Film Dosimeter

International Nuclear Information System (INIS)

Nguyen Nguyet Dieu; Doan Binh; Pham Thu Hong; Cao Van Chung; Nguyen Thanh Duoc

2011-01-01

B3 dosimeter is a thin film with average thickness of 0.0194 mm, which is supplied by the Gex company, the United States. This dosimeter was influenced by many factors: light, temperature, humidity during and after irradiation process. In fact, B3 film dosimeters will be stable under certain conditions such as tightly sealed packs, controlled irradiation and stored temperature after irradiated. Therefore, investigation of the stability effect of postirradiated B3 film dosimeters on the heating temperature, heating time and storing time is carried out before the absorbed dose is read and followed standard reading procedures. When exposed to ionizing radiation, the dosimeters change from colorless to colour. The absorbed doses are read on a Genesys 20 spectrophotometer at a wavelength of 544 nm. Absorbed dose range is investigated from 0.55 to 80 kGy. Experimental results were indicated that colour stability of the postirradiated dosimeters at a temperature of 65 ± 3 o C for 30 minutes and keeping them in desiccator for 5 minutes before read out. Under these conditions, colour stability of B3 film dosimeter has maintained for 3 months. (author)

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

Science.gov (United States)

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

2017-06-01

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

Calibration of film dosimeters by means of absorbed dose calorimeters

International Nuclear Information System (INIS)

Nikolaev, S.M.; Vanyushkin, B.M.; Kon'kov, N.G.

1980-01-01

Methods of graduating film dosimeters by means of calorimeters of absorbed doses, are considered. Graduating of film dosimeters at the energies of accelerated electrons from 4 to 10 MeV can be carried out by means of quasiadiabatic calorimeter of local absorption, the absorber thickness of which should not exceed 5-10% of Rsub(e) value, where Rsub(e) - free electron path of the given energy. In this case film is located inside the calorimeter. For graduating films with thickness not less than (0.1-0.2)Rsub(e) it is suggested to use calorimeter of full absorption; then the graduated dosimeters are located in front of the calorimeter. Graduation of films at small energies of electrons is exercised by means of a package of films, approximately Rsub(e) thick. A design of quasiadiabatic calorimeter, intended for graduating dosimeters within the energy range of electron beam from 4 to 10 MeV, is considered. The quasiadiabatic calorimeter is a thin graphite tablet with heater and thermocouple, surrounded by foam plastic thermostating case. Electricity quantity, accumulated during the radiation field pass, is measured in the case of using the quasiadiabatic calorimeter for film graduating. The results of graduating film dosimeters, obtained using film package with Rsub(e) thickness, are presented. The obtained results coincide within 5% limits with the data known beforehand [ru

Dating by fission track method: study of neutron dosimetry with natural uranium thin films

International Nuclear Information System (INIS)

Iunes, P.J.

1990-06-01

Fission track dating is described, focalizing the problem of the decay constant for spontaneous fission of 238 U and the use of neutron dosimetry in fission track analysis. Experimental procedures using thin films of natural uranium as neutron dosimeters and its results are presented. The author shows a intercomparison between different thin films and between the dosimetry with thin film and other dosimetries. (M.V.M.). 52 refs, 12 figs, 9 tabs

Dating by fission track method: study of neutron dosimetry with natural uranium thin films; Datacao com o metodo dos tracos de fissao: estudo da dosimetria de neutrons com filmes finos de uranio natural

Energy Technology Data Exchange (ETDEWEB)

Iunes, P J

1990-06-01

Fission track dating is described, focalizing the problem of the decay constant for spontaneous fission of {sup 238} U and the use of neutron dosimetry in fission track analysis. Experimental procedures using thin films of natural uranium as neutron dosimeters and its results are presented. The author shows a intercomparison between different thin films and between the dosimetry with thin film and other dosimetries. (M.V.M.). 52 refs, 12 figs, 9 tabs.

Neutron dosimeters and survey meters in accelerators, reactors and other neutron environments

International Nuclear Information System (INIS)

1989-03-01

Neutron fields in occupationally accessible areas around nuclear reactors, radioisotope sources and medical and high energy accelerators have been characterized using currently available information. Neutron, rem meters, such as the Leake detector, are the most suitable instruments available for conducting neutron dose rate surveys in the vicinity of radioisotope neutron sources, nuclear reactors and medical accelerators. However, these instruments have been shown to be deficient in that they overrespond by a factor of four to neutrons in the 0.1 to 1 MeV range and are insensitive to neutrons from about 1 eV up to about 10 keV. Also, they are insensitive to neutrons above 20 MeV and their use must be restricted near high energy accelerators where significant numbers of neutrons above 20 MeV are known to be present. The most suitable instrument of measure dose from neutrons above 20 MeV is the 12 C(n,2n) 11 C scintillation chamber. Commercially available rem meters frequently use BF 3 counters in the pulse mode to detect thermal neutrons. Therefore, measurements around pulsed accelerators must be made with caution to ensure that the detector is not saturated during each pulse and that the accelerator pulse period is greater than the response time of the detector. The personal neutron dosimeters currently available either are known to be insensitive to neutrons above 20 MeV or have not been tested. Also, all except the albedo dosimeter are insensitive to or have not been tested for neutron energies in the range 1 eV to 10 keV. Several dosimeter types respond reasonably well to neutrons in the energy range 0.1 to 15 MeV, for example, CR-39, bubble and superheated drop detectors. However, the first gas a lower limit of sensitivity of about 0.3 mSv. The bubble detector can be designed to measure doses as small as 1μSv and offers the additional benefit of direct-reading capability. The superheated drop detector is not suitable for use around pulsed accelerators because

A PC based thin film dosimeter system

DEFF Research Database (Denmark)

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

2000-01-01

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

Commissioning optically stimulated luminescence in vivo dosimeters for fast neutron therapy

Energy Technology Data Exchange (ETDEWEB)

Young, Lori A., E-mail: layoung@uw.edu; Sandison, George [Department of Radiation Oncology, University of Washington, Seattle, Washington 98115 (United States); Yang, Fei [Sylvester comprehensive Cancer Center, University of Miami, Miami, Florida 33124 (United States); Woodworth, Davis [Department of Physics, University of Reno, Reno, Nevada 89557 (United States); McCormick, Zephyr [Department of Physics, University of California, Santa Barbara, California 93106 (United States)

2016-01-15

Purpose: Clinical in vivo dosimeters intended for use with photon and electron therapies have not been utilized for fast neutron therapy because they are highly susceptible to neutron damage. The objective of this work was to determine if a commercial optically stimulated luminescence (OSL) in vivo dosimetry system could be adapted for use in fast neutron therapy. Methods: A 50.5 MeV fast neutron beam generated by a clinical neutron therapy cyclotron was used to irradiate carbon doped aluminum oxide (Al{sub 2}O{sub 3}:C) optically simulated luminescence dosimeters (OSLDs) in a solid water phantom under standard calibration conditions, 150 cm SAD, 1.7 cm depth, and 10.3 × 10.0 cm field size. OSLD fading and electron trap depletion studies were performed with the OSLDs irradiated with 20 and 50 cGy and monitored over a 24-h period to determine the optimal time for reading the dosimeters during calibration. Four OSLDs per group were calibrated over a clinical dose range of 0–150 cGy. Results: OSLD measurement uncertainties were lowered to within ±2%–3% of the expected dose by minimizing the effect of transient fading that occurs with neutron irradiation and maintaining individual calibration factors for each dosimeter. Dose dependent luminescence fading extended beyond the manufacturer’s recommended 10 min period for irradiation with photon or electron beams. To minimize OSL variances caused by inconsistent fading among dosimeters, the observed optimal time for reading the OSLDs postirradiation was between 30 and 90 min. No field size, wedge factor, or gantry angle dependencies were observed in the OSLDs irradiated by the studied fast neutron beam. Conclusions: Measurements demonstrated that uncertainties less than ±3% were attainable in OSLDs irradiated with fast neutrons under clinical conditions. Accuracy and precision comparable to clinical OSL measurements observed with photons can be achieved by maintaining individual OSLD calibration factors and

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

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

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

Directory of Open Access Journals (Sweden)

S.A. Santa

2017-06-01

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

Qualification of the monitor Pug-7N like dosimeter for neutrons

International Nuclear Information System (INIS)

Benites R, J. L.; Vega C, H. R.; Murillo O, R.; Velazquez F, J. B.

2011-10-01

By means of an inter-comparison method, the monitor for neutrons Pug-7N was enabled like dosimeter for neutrons of two magnitudes: the environmental equivalent dose, H*(10), and the H equivalent dose. The monitor Pug-7N has a plastic detector of scintillation Pns-20 that can be used inside or outside of its polyethylene cylindrical moderator. This designed to detect the neutrons presence that is shown in ana logical form by means of a fast count. Although the instrument is useful to detect the neutrons presence its design it does not allow to estimate the dose. With the purpose of enabling it as dosimeter for neutrons, their response was compared with the response of the area monitor for neutrons Bert hold Lb 6411 and Eberline NRD model Asp-1. Under the same irradiation conditions the 3 instruments were exposed to a source of 241 AmBe of 3.7E(9) Bq (100 mCi) of activity whose spectrum and dosimetric magnitudes were determined with a spectrometric system of Bonner spheres with scintillator of 6 Lil(Eu) and the NSDUAZ code. Conversion factors of H*(10)/cpm and H/cpm were obtained for the two options of the monitor detector Pug-7N, with this procedure the monitor Pug-7N besides determining the presence of neutrons, it has been enabled for their use as dosimeter for neutrons. (Author)

Towards a new thickness-independent gamma radiation plastic film dosimeter

International Nuclear Information System (INIS)

Vieira, Marli Barbosa; Araujo, Patricia L.; Araujo, Elma S.

2013-01-01

A 100% national single-use gamma radiation plastic film dosimeter is presented in this work. A new approach for the development of this material allowed a step forward in the performance of poly (methyl metacrylate) films (PMMA) colored with bromothymol blue (BTB) acid-base indicator. We manage to improve dosimeter performance by introducing a gamma radiation insensitive dye to compensate film thickness variations. By doing so, we were able to obtain consistent dose-response correlations within a set of samples presenting 46 to 110 micrometers in thickness. Hence, our PMMA/BTB-P film dosimeter is suitable to measure absorbed dose in the 2-100kGy range even when film thickness undergoes more than 100% of variation. In addition, dose response data remain practically unaltered for four months after the exposure, when dosimeter films are kept in dark conditions and under refrigeration. The radiation effects on the optical properties were evaluated for Ultraviolet-Visible (UV-Vis) spectrophotometric analysis. Data of characteristic dose-response correlation in terms of changes in the maximum UV-Vis absorption due to radiation, and stability in time are also described. This potential new product is a promising tool for industrial radiation facilities, especially in gamma sterilization of medical supplies. (author)

Study of an individual neutron dosimeter

International Nuclear Information System (INIS)

Debeauvais, M.; Tripier, J.

1976-01-01

A dosimeter using Kodak LR 115 cellulose nitrate as detecting material was designed. It serves to determine 3 neutron energy ranges. The 6 Li(n,α)t reaction is used for the thermal region, the sensitivity being 0.2mrads to 1 rad for neutron energies between thermal and 0.05eV. The same reaction defines the 0.05eV to 1000eV energy range but the detection system is placed inside a cadmium screen; the sensitivity is 0.2 to 500rads. Finally above 1MeV the neutron reactions used are those on the detector components themselves, i.e. elastic collisions and (nα) reactions on carbon, nitrogen and oxygen nuclei. Detection is possible between 0.7 and 700 rads [fr

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

Science.gov (United States)

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

2017-07-01

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

Digital neutron dosimeter

International Nuclear Information System (INIS)

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

1978-01-01

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

Dosimeter incorporating radiophotoluminescent detectors for thermal neutrons and γ-rays in n-γ fields

Energy Technology Data Exchange (ETDEWEB)

Salem, Y.O. [Groupe RaMsEs, Institut Pluridisciplinaire Hubert Curien (IPHC), UMR 7178 CNRS/IN2P3, 23 rue du Loess, BP 28, F-67037 Strasbourg Cedex 2 (France); Nachab, A., E-mail: a.nachab@uca.ma [Département de physique, Faculté Poly-disciplinaire, Université Cadi Ayyad, Route Sidi Bouzid BP 4162, 46000 Safi (Morocco); Roy, C.; Nourreddine, A. [Groupe RaMsEs, Institut Pluridisciplinaire Hubert Curien (IPHC), UMR 7178 CNRS/IN2P3, 23 rue du Loess, BP 28, F-67037 Strasbourg Cedex 2 (France)

2016-10-15

We have developed a dosimeter associating different neutron converters with two radiophotoluminescent detectors to measure thermal neutrons and γ-rays in a mixed n-γ field. Tests show that the H{sup ∗}(10) and H{sub p}(10) responses to thermal neutrons and γ-rays are linear with detection limits lower than 0.4 mSv. The angular dependence of the dosimeter response is satisfactory and the influence of a phantom on the results is examined.

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

DEFF Research Database (Denmark)

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

2005-01-01

Thin-film dosimeters (Riso B3 and alanine films) were irradiated at 10 MeV and 80-120 keV electron accelerators, and it has been shown that the radiation response of the dosimeter materials (the radiation chemical yields) are constant at these irradiation energies. However, dose gradients within ...... are present within the dosimeter. (C) 2005 Elsevier Ltd. All rights reserved....

The Response of Alanine Dosimeters in Thermal Neutron Fields

DEFF Research Database (Denmark)

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

response of all pellets could be reproduced by calculations within a uncertainty of 5 %. For all experiments three dose components have been separated. A proton dose is generated in the 14N(n,p)14C reaction. Secondary gammas are generated by various (n,γ) reactions, dominated by the 2.2 MeV photon from...... experiments the dosimeters will be exposed to higher neutron energies, which are more typical for BNCT treatments. References: [1] Barth, R.F; 2009: Boron neutron capture therapy at the crossroads: Challenges and opportunities. Applied Radiation and Isotopes 67, 3-6. [2] Rogus, R.D.; Harling, O.K.; Yanch, J.C...... for treatment of liver metastases. Applied Radiation and Isotopes 67, 238-241. [4] Sharpe, P.; Sephtan, J.; 2000: An automated system for the measurement of alanine/EPR dosimeters. Applied Radiation and Isotopes 52, 1185-1188....

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

International Nuclear Information System (INIS)

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

2007-01-01

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

Uses of polymer-alanine film/ESR dosimeters in dosimetry of ionizing radiation

International Nuclear Information System (INIS)

Xie Liqing; Zhang Yinfeng; Dai Jinxian; Lu Ting; Chen Ruyi; Yang Hua

1993-01-01

Alanine ESR dosimetry is a reliable method, used in a various fields of ionizing radiation. The polymer-alanine film/ESR dosimeters of 0.3 -0.4 mm thickness were prepared and their dosimetric properties were studied for 60 Co γ photons and 3 - 5 MeV electrons in the dose range from 20 Gy to 100 kGy. The results show that under normal conditions the alanine calibration curves are linear in the dose range from 100 Gy to 10kGy. The dose profiles at the electron radiation field were measured with the film alanine dosimeters. The polymer-alanine film dosimeters were used for ion implantation of 400 keV ion implantor. Their dose response and energy dependence were investigated initially. (Author)

Neutron dosimetry at commercial nuclear plants. Final report of Subtask B: dosimeter response

Energy Technology Data Exchange (ETDEWEB)

Cummings, F.M.; Endres, G.W.R.; Brackenbush, L.W.

1983-03-01

As part of a larger program to evaluate personnel neutron dosimetry at commercial nuclear power plants, this study was designed to characterize neutron dosimeter responses inside the containment structure of commercial nuclear plants. In order to characterize those responses, dosimeters were irradiated inside containment at 2 pressurized water reactors and at pipe penetrations outside the biological shield at two boiling water reactors. The reactors were operating at full power during the irradiations. Measurements were also performed with electronic instruments, the tissue equivalent proportional counter (TEPC), and portable remmeters, SNOOPY, RASCAL and PNR-4.

Neutron dosimetry at commercial nuclear plants. Final report of Subtask B: dosimeter response

International Nuclear Information System (INIS)

Cummings, F.M.; Endres, G.W.R.; Brackenbush, L.W.

1983-03-01

As part of a larger program to evaluate personnel neutron dosimetry at commercial nuclear power plants, this study was designed to characterize neutron dosimeter responses inside the containment structure of commercial nuclear plants. In order to characterize those responses, dosimeters were irradiated inside containment at 2 pressurized water reactors and at pipe penetrations outside the biological shield at two boiling water reactors. The reactors were operating at full power during the irradiations. Measurements were also performed with electronic instruments, the tissue equivalent proportional counter (TEPC), and portable remmeters, SNOOPY, RASCAL and PNR-4

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

DEFF Research Database (Denmark)

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

2004-01-01

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

Fabrication of a flexible polycarbonate/porphyrin film dosimeter for high dose dosimetry

Energy Technology Data Exchange (ETDEWEB)

Feizi, Shahzad [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of). Radiation Application Research School

2017-10-01

Dyed polycarbonate (PC) Radiochromic films with 20 μm thickness were prepared by casting of organic solution of PC containing 0.5 wt.% tetrakis (pentafluorophenyl) porphyrin (TPPF{sub 20}) on a glass petri dish. Characterization of the film as a routine dosimeter was studied. On subjecting PC/TPPF{sub 20} film dosimeter to gamma radiation, a gradual decrease in the color of films was observed. The sensitivity of these films and the linearity of dose-response curves were studied under {sup 60}Co γ-rays expose in dose range of 0-100 kGy. The results were compared with the commercial and non-commercial dosimeters. Experimental parameters including humidity, temperature and pre-irradiation (shelf-life) and post-irradiation storage in dark and in indirect sunlight were examined. The maximum absorbance of soret band of TPPF{sub 20} had a bathochromic shift and appeared at 414 nm which remained intact in the investigated dose range. The dyed films characteristics were found to be stable enough in media with high degrees of temperature and humidity. The results indicate that radiation induced decoloration of PC/TPPF{sub 20} films can be reliably used in high dose dosimetry.

Intercomparison of personnel dosimetry for thermal neutron dose equivalent in neutron and gamma-ray mixed fields

International Nuclear Information System (INIS)

Ogawa, Yoshihiro

1985-01-01

In order to consider the problems concerned with personnel dosimetry using film badges and TLDs, an intercomparison of personnel dosimetry, especially dose equivalent responses of personnel dosimeters to thermal neutron, was carried out in five different neutron and gamma-ray mixed fields at KUR and UTR-KINKI from the practical point of view. For the estimation of thermal neutron dose equivalent, it may be concluded that each personnel dosimeter has good performances in the precision, that is, the standard deviations in the measured values by individual dosimeter were within 24 %, and the dose equivalent responses to thermal neutron were almost independent on cadmium ratio and gamma-ray contamination. However, the relative thermal neutron dose equivalent of individual dosimeter normalized to the ICRP recommended value varied considerably and a difference of about 4 times was observed among the dosimeters. From the results obtained, it is suggested that the standardization of calibration factors and procedures is required from the practical point of radiation protection and safety. (author)

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

Qualification of the monitor Pug-7N like dosimeter for neutrons; Habilitacion del monitor PUG-7N como dosimetro para neutrones

Energy Technology Data Exchange (ETDEWEB)

Benites R, J. L. [Centro Estatal de Cancerologia de Nayarit, Av. Enfermeria, Fracc. Fray Junipero Serra, 63000 Tepic, Nayarit (Mexico); Vega C, H. R.; Murillo O, R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Velazquez F, J. B., E-mail: jlbenitesr@prodigy.net.mx [Universidad Autonoma de Nayarit, Postgrado CBAP, Carretera Tepic Compostela Km. 9, Xalisco, Nayarit (Mexico)

2011-10-15

By means of an inter-comparison method, the monitor for neutrons Pug-7N was enabled like dosimeter for neutrons of two magnitudes: the environmental equivalent dose, H*(10), and the H equivalent dose. The monitor Pug-7N has a plastic detector of scintillation Pns-20 that can be used inside or outside of its polyethylene cylindrical moderator. This designed to detect the neutrons presence that is shown in ana logical form by means of a fast count. Although the instrument is useful to detect the neutrons presence its design it does not allow to estimate the dose. With the purpose of enabling it as dosimeter for neutrons, their response was compared with the response of the area monitor for neutrons Bert hold Lb 6411 and Eberline NRD model Asp-1. Under the same irradiation conditions the 3 instruments were exposed to a source of {sup 241}AmBe of 3.7E(9) Bq (100 mCi) of activity whose spectrum and dosimetric magnitudes were determined with a spectrometric system of Bonner spheres with scintillator of {sup 6}Lil(Eu) and the NSDUAZ code. Conversion factors of H*(10)/cpm and H/cpm were obtained for the two options of the monitor detector Pug-7N, with this procedure the monitor Pug-7N besides determining the presence of neutrons, it has been enabled for their use as dosimeter for neutrons. (Author)

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)

Evaluation of the implementation and use of active personal dosimeters for neutrons in Brazil

International Nuclear Information System (INIS)

Castro B, C. P.; Wagner P, W.; De Souza P, K. C.

2014-08-01

This work was conducted through of a field research based on a questionnaire sent to users of active personal dosimeters. A retrospective study of the last six years was also carried out of the services in the Neutron Metrology Laboratory (2008-2013) referent to the active personal dosimeters, taking into consideration the standards ISO-8529-3 and IEC-61526. The active personal dosimeters are defined as any instrument of individual monitoring with direct reading capacity, used by individuals exposed to ionizing radiation fields. Through research was verified that the active personal dosimeters work associated with other dosimeter types. Considering all dosimeters declared in the questionnaire, only two dosimeters (MGP brand Dmc 2000-GN model and the brand ATOMTEX model AT2503A) have conformity declaration with the international standard IEC-61526: 2005 reported by the manufacturers. (author)

Practical consequences for the use of a personal dosimeter for fast neutrons based on CR39 exposed up to one year

International Nuclear Information System (INIS)

Boschung, Markus; Fiechtner, Annette; Mayer, Sabine; Wernli, Christian

2008-01-01

Full text: At the Paul Scherrer Institut a personal neutron dosimetry system based on chemically etched CR-39 detectors and automatic track counting is in routine use since 1998. In its original design, the dosimeter is sensitive to thermal neutrons and to neutrons in the energy range from 200 keV up to several MeV. The standard exposition period is 3 months. Recently, a novel concept for individual monitoring was implemented at CERN. In this concept, each worker who possibly enters a radiation zone is equipped with a combined dosimeter for the measurement of personal photon and neutron doses. The dosimeter for photon dose measurement has an instant readout capability and dose measurements are done monthly. The dosimeter for neutron measurement is based on CR-39 detectors and is sensitive to fast neutrons only. The CR-39 detector is only evaluated and a neutron dose determined if the monthly personal photon dose exceeds 2 mSv or if the exposition period of the neutron dosimeter exceeds one year. This novel regime of use of the neutron dosimeter has had some important consequences for its practical implementation. A priori, the wearing period of a neutron dosimeter is not known and can range from 1 month up to 12 or even more months. A good knowledge of the long-term behaviour and characteristics of the detector material is needed. But also organisational and administrative issues have to be considered. The paper will outline the adopted procedure covering not only technical but also organisational aspects. The long-term behaviour of background track density and response to 241 Am-Be over one year are described as well as calibrations performed with 241 Am-Be and 252 Cf sources and in the High-Energy Reference Field Facility at CERN (CERF). The concept of individual monitoring at CERN could be transferred to other locations with high energy accelerators such as PSI and DESY. The experience gained with the neutron dosimeter based on CR-39 since introduction of the

Raman vibrational spectra of thymol blue dyed polyvinyl alcohol (PVA) film dosimeters

International Nuclear Information System (INIS)

Lepit, A.; Saion, E.B.; Susilawati; Doyan, A.; Wan Yusoff, W.M.D.

2002-01-01

Radiation-sensitive dyed polyvinyl alcohol (PVA) film indicators containing chloral hydrate and acid-sensitive thymol blue dye have been studied for routine food irradiation dosimeters. The free standing dyed film dosimeters of different chloral hydrate concentrations (0.1, 0.5, 1.0, 2.0 and 2.5 g) were irradiated with the absorbed dose ranges from 1 kGy to 12 kGy using gamma rays from Co-60 teletherapy. Upon exposure the dosimeters undergo chemical change and become more acidic, resulting in colour change from yellow to red at the critical doses depending on the chloral hydrate concentrations. The radiation-induced change in colour was analysed using UV-Vis spectrometer that the absorption spectra produced two maximal of the visible bands peaking at 445 nm for low doses and 554 nm for high doses. Spectra of inelastic Raman scattering photons corresponding to Raman shift frequency of unirradiated and irradiated films were measured using a dispersive Raman spectrometer. The spectral intensity of C=C, C-0 and S-H molecular vibration peaks for their respective Raman shifts were studied which provide the dose response to the change of dye molecular structure of the dosimeters. (Author)

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.)

Study of a plastic detector as a neutron dosimeter

International Nuclear Information System (INIS)

Cuauhtecatl Hernandes, V.

1982-01-01

Studies were carried out through nuclear reactions (n, p); (n, heavy ion), and (n,α) of the dosimetric properties of CR 39 commercial brand polymers. A system was devised for calculating the number of neutron induced nuclear reactions and geometric absolute efficiency factors. Feasibility of the utilization of CR 39 in monitoring and in personnel dosimeters is also discussed. (author)

Results of the systematic study of neutron dosimeters and neutron radiometers responses from Bruyeres and Valduc's experiments

International Nuclear Information System (INIS)

Pras, Ph.; Ledoux, X.; Patin, Y.

1999-01-01

This document gives the results of the systematic study of neutron dosimeters (Bubbles detectors) and neutron radiometers (Cramal, Nausicaa, EGG Lb6411) with standard sources and with the Bruyeres Van de Graaff 4MV accelerator. The dose equivalent rate response as a function of the neutron energy is parameterized. Even for low dose equivalent rate, a good reproducibility of the measurements is found in the strict respect of a given method. The response of the different systems is independent of the dose equivalent rate. (author)

Solid state neutron dosimeter for space applications. Final Report

International Nuclear Information System (INIS)

Entine, G.; Nagargar, V.; Sharif, D.

1990-08-01

Personnel engaged in space flight are exposed to significant flux of high energy neutrons arising from both primary and secondary sources of ionizing radiation. Presently, there exist no compact neutron sensor capable of being integrated in a flight instrument to provide real time measurement of this radiation flux. A proposal was made to construct such an instrument using special PIN silicon diode which has the property of being insensitive to the other forms of ionizing radiation. Studies were performed to determine the design and construction of a better reading system to allow the PIN diode to be read with high precision. The physics of the device was studied, especially with respect to those factors which affect the sensitivity and reproducibility of the neutron response. This information was then used to develop methods to achieve high sensitivity at low neutron doses. The feasibility was shown of enhancing the PIN diode sensitivity to make possible the measurement of the low doses of neutrons encountered in space flights. The new PIN diode will make possible the development of a very compact, accurate, personal neutron dosimeter

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

Personnel Neutron Monitoring at AB Atomenergi

International Nuclear Information System (INIS)

Hagsgaard, S.; Widell, C.O.

1964-02-01

The routine personnel monitoring of fast neutrons is carried out by the counting of tracks in a nuclear emulsion. The tracks are counted in a microscope on a projection screen. This is a very tedious job and is only done on irradiated films which are counted over 6 mm 2 . The irradiated films are selected according to the recorded dose on the gamma film. It is often difficult to tell how much the visible tracks have faded during a two-weeks period. Fortunately the fading does not often exceed 20 % for this period. If the dosimeter has been gamma-irradiated, it may be difficult to recognize the proton tracks. If the film is stored for some time before being developed, this gamma fog will to some extent fade away. For large neutron doses a foil activation dosimeter is used. This dosimeter consists of a cadmium-shielded phosphorus foil, a cadmium shielded gold foil and an unshielded gold foil. The phosphorus foil has to be counted shortly after exposure

Personnel Neutron Monitoring at AB Atomenergi

Energy Technology Data Exchange (ETDEWEB)

Hagsgaard, S; Widell, C O

1964-02-15

The routine personnel monitoring of fast neutrons is carried out by the counting of tracks in a nuclear emulsion. The tracks are counted in a microscope on a projection screen. This is a very tedious job and is only done on irradiated films which are counted over 6 mm{sup 2}. The irradiated films are selected according to the recorded dose on the gamma film. It is often difficult to tell how much the visible tracks have faded during a two-weeks period. Fortunately the fading does not often exceed 20 % for this period. If the dosimeter has been gamma-irradiated, it may be difficult to recognize the proton tracks. If the film is stored for some time before being developed, this gamma fog will to some extent fade away. For large neutron doses a foil activation dosimeter is used. This dosimeter consists of a cadmium-shielded phosphorus foil, a cadmium shielded gold foil and an unshielded gold foil. The phosphorus foil has to be counted shortly after exposure.

Systematic approach to personnel neutron monitoring

International Nuclear Information System (INIS)

Griffith, R.V.; Hankins, D.E.

1980-01-01

NTA film and albedo detectors represent the major portion of personnel dosimeters now used for occupational neutron monitoring. However, recent attention to the spectral response of these systems has demonstrated the need for detectors that have a better match to the fields being monitored. Recent developments in direct recoil track etch dosimeters present some intriguing alternatives, and careful use of 237 Np fission fragment detectors offers the advantage of a good dose equivalent spectral match. Work continues on a number of other new detector mechanisms, but problems with sensitivity, energy response, gamma interference, etc., continue to prevent development of most mechanisms into viable personnel dosimeters. Current dosimeter limitations make a systematic approach to personnel neutron monitoring particularly important. Techniques have been developed and tested, using available portable survey instruments, that significantly improve the quality of dosimeter interpretation. Even simple spectrometry can be done with modest effort, significantly improving the health physicists ability to provide accurate neutron monitoring

Chemical Processing effects on the radiation doses measured by Film Dosimeter System

International Nuclear Information System (INIS)

Mihai, F.

2009-01-01

Halide film dosimetry is a quantitative method of measurement of the radiation doses. The fog density and chemical processing of the dosimeter film affect the radiation dose measurement accuracy. This work presents the effect of the developer solution concentration on the response of the dosimetric film which different fog densities. Thus, three batches of film, dosimeters with following fog density 0.312 ± 1.31 %, 0.71 ± 0.59% and 0.77 ± 0.81 %, were irradiated to 137 Cs standard source to dose value of 1mSv. The halide films have been chemical processed at different concentrations of the developer solution: 20 %; 14.29 %; 11.11%; all other physics-chemical conditions in baths of development have been kept constants. Concentration of 20% is considered to be chemical processed standard conditions of the films. In case of the films exposed to 1 mSv dose, optical density recorded on the low fog films processed at 20% developer solution is rather closed of high fog film optical densities processed at 11.11% developer solution concentration. Also, the chemical processing effect on the image contrast was taken into consideration

Temperature, humidity and time. Combined effects on radiochromic film dosimeters

DEFF Research Database (Denmark)

Abdel-Fattah, A.A.; Miller, A.

1996-01-01

The effects of both relative humidity and temperature during irradiation on the dose response of FWT-60-00 and Riso B3 radiochromic film dosimeters have been investigated in the relative humidity (RH) range 11-94% and temperature range 20-60 degrees C for irradiation by Co-60 photons and 10-Me......V electrons. The results show that humidity and temperature cannot be treated as independent variables, rather there appears to be interdependence between absorbed dose, temperature, and humidity. Dose rate does not seem to play a significant role. The dependence of temperature during irradiation is +0.......25 +/- 0.1% per degrees C for the FWT-60-00 dosimeters and +0.5 +/- 0.1% per degrees C For Riso B3 dosimeters at temperatures between 20 and 50 degrees C and at relative humidities between 20 and 53%. At extreme conditions both with respect to temperature and to humidity, the dosimeters show much stronger...

OSL and TL dosimeter characterization of boron doped CVD diamond films

Science.gov (United States)

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

2005-04-01

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

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

International Nuclear Information System (INIS)

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

2008-01-01

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

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

DEFF Research Database (Denmark)

Chung, W.H.; Miller, A.

1994-01-01

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

An attempt to fabricate an ion injection type fast neutron dosimeter

International Nuclear Information System (INIS)

Pells, G.P.; Hughes, A.E.

1976-10-01

This report describes the results of work carried out to investigate a novel type of solid state, fast neutron dosimeter. The concept and quantitative features of the dosimeter, in which collisions between fast neutrons and ions in a source compound cause the ions to be injected into a host compound where they could then be detected by their characteristic luminescence, are described. It is shown that with the aid of a complex reader mrad sensitivities should in principle be possible. Initial experiments showed that accelerator implantation of Bi 3+ ions into CaO gives a linear dependence of luminescence output with fluence of activator ions. A number of host/activator combinations were investigated from which SiO 2 :Gd 3+ appeared the most promising. Host/activator configurations are briefly considered. The production of compacts of SiO 2 and Gd 2 O 3 ultrafine powders is described. Attempts were made to characterise these compacts using scanning electron microscopy and luminescence spectroscopy. After fast neutron irradiation to 250 Mrad no Gd 3+ ion injection could be detected. An alternative configuration of ultrafine SiO 2 powder dispersed in a solid Gd(NO 3 ) 3 .5H 2 O matrix is described but again no Gd 3+ ion injection into the SiO 2 could be detected after fast neutron irradiation. Perspex, as a host, was also tried without success. An appendix is included which demonstrates that the lack of success in detecting ion-injection may be largely due to the optically opaque nature of the specimens that could be produced. (author)

Temperature, humidity and time., Combined effects on radiochromic film dosimeters

International Nuclear Information System (INIS)

Abdel-Fattah, A.A.; Miller, A.

1996-01-01

The effects of both relative humidity and temperature during irradiation on the dose response of FWT-60-00 and Riso B3 radiochromic film dosimeters have been investigated in the relative humidity (RH) range 11-94% and temperature range 20-60 o C for irradiation by 60 Co photons and 10-MeV electrons. The results show that humidity and temperature cannot be treated as independent variables, rather there appears to be interdependence between absorbed dose, temperature, and humidity. Dose rate does not seem to play a significant role. The dependence of temperature during irradiation is + 0.25 ± 0.1% per o C for the FWT-60-00 dosimeters and +0.5 ± 0.1% per o C for Riso B3 dosimeters at temperatures between 20 and 50 o C and at relative humidities between 20 and 53%. At extreme conditions both with respect to temperature and to humidity, the dosimeters show much stronger dependences. Whenever possible one should use dosimeters sealed in pouches under controlled intermediate humidity conditions (30-50%) or, if that is impractical, one should maintain conditions of calibration as close as possible to the conditions of use. Without that precaution, severe dosimetry errors may result. (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.

Detector and dosimeter for neutrons and other radiation

International Nuclear Information System (INIS)

Apfel, R.E.

1979-01-01

A radiation detector and dosimeter is based on the fact that a sufficiently finely-dispersed liquid suspended in a host liquid of high viscosity or gel is stable at temperatures above its normal boiling point for long periods of time provided it is protected from contact with walls, or other types of initiators which can cause volatilization or vaporization of the droplets. Radiation, and particularly neutron radiation of sufficient energy and intensity on coming in contact with such droplets can trigger volatilization. The volume of vapor evolved can then serve as a measure of radiation intensity and dosage

Personnel ionizing radiation dosimeter

International Nuclear Information System (INIS)

Williams, R.A.

1975-01-01

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

Some aspects on neutron dosimetry

International Nuclear Information System (INIS)

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

1988-01-01

The American National Council on Radiation Protection and measurements (1) has recently issued a statement regarding dose limitation system for neutrons. The changes proposed in that statement presented substantial problems regarding the personnel exposure to neutrons and had pointed out the need to reassess an adequate current neutron dosimetry practice. Generally, the same types of dosimeters i.e. Nuclear Track (NTA films) and TLD-Albedo, have been used at major nuclear facilities over the past 15 years. here recently, other dosimetry methods such as track etch with polycarbonates such as CR-39 have been developed. However these should be recognized as local systems aiming to the development of better and more applicable dosimeters. 4 tab

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

Dehydrochlorinated poly vinyl alcohol (PVA) films for food irradiation dosimeters

International Nuclear Information System (INIS)

Susilawati; Saion, E.B.; Doyan, A.; Lepit, A.; Wan Yusoff, W.M.D.

2002-01-01

Radiation sensitive dosimeters based on dyed poly vinyl alcohol (PVA) films containing chloral hydrate CCl 3 CH(OH) 2 and acid-sensitive cresol-red dye have been developed for use in food irradiation dosimetry. These polymer dosimeters undergo colour change from yellow (colour of basic form) to red (colour of acid form) upon exposure to gamma radiation. The radiation-induced change in colour was analysed using UV-Vis spectrometer. The absorption spectra produced two absorption modes, peaking at 438 nm for low doses and 529 nm for high doses. The dose-response was obtained by the changes in absorbance as a function of the absorbed dose. Results of the dose-response curves show the absorption decreases and increases experientially at modes 438 nm and 529 nm respectively with absorbed dose. The change in colour of the irradiated films was analysed using Raman spectrometer, which provides the spectra of molecular stretching modes of vibration of some chemical bonds in the films. The relative intensity at C-Cl stretching peaks of chloral hydrate decreases with absorbed dose and makes the films more acidic. Consequently the relative intensity at S-H and C=C stretching peaks of the dye increases with absorbed dose as the acid reacts with the dye and changes the structure and colour of the dye. (Author)

Application of semiconductor MOSFET and pin diode dosimeters to epithermal neutron beam dose distribution measurements in phantoms

International Nuclear Information System (INIS)

Carolan, M.G.; Wallace, S.A.; Allen, B.J.; Rosenfeld, A.B.; Mathur, J.N.

1996-01-01

For any clinical application of Boron Neutron Capture Therapy (BNCT) fast and accurate dose calculations will be required for treatment planning. Such calculations are also necessary for the planning and interpretation of results from pre-clinical and clinical trials where the speed of calculation is not so critical. A dose calculation system based on the MCNP Monte Carlo Neutron transport code has been developed by Wallace. This system takes image data from CT scans and constructs a voxel based geometrical model for input into MCNP. To validate the calculations, a number of phantoms were constructed and exposed in the HB11 epithermal neutron beam at the HFR of the CEC Joint Research Centre in Petten. The doses recorded by arrays of PIN diode neutron dosimeters and MOSFET gamma dosimeters in these phantoms were compared with the calculated results from the MCNP dose planning system. Initial results have been reported elsewhere. Poster 197. (author)

A systematic approach to personnel neutron monitoring

International Nuclear Information System (INIS)

Griffith, R.V.; Hankins, D.E.

1980-01-01

In selection, calibration and interpretation of personnel neutron dosimeters used in radiation protection, adequate attention is often not given to matching the characteristics of the dosimeter with the quality of the neutron field. A particular concern is the use of albedo detectors which have little energy response similarity to the neutron dose equivalent conversion curve. At the Lawrence Livermore Laboratory we have developed a system for dosimeter calibration and neutron field characterization using Bonner spheres and remmeters. Rapid surveys of the work area with detectors in 3-in and 9-in polyethylene spheres establish a qualitative estimate of spectral variation found in the facility. We also use this data to determine the appropriate albedo dosimeter calibration factors. At several locations representing the spectral range, multisphere spectra measure-ments are made and the spectrum weighted dose equivalent rates calculated. These rates are compared with survey instrument results to establish correction factors for the relative over- or under-response expected from these instruments, particularly in highly moderated neutron fields where remmeters overrespond. We also use the spectral information to determine the appropriateness of dosimeters considered for future use. This technique has been applied at power reactors to provide information valuable to selection of proper personnel dosimeters. We find that the spectral range is sufficiently narrow that albedo detectors can be used with confidence. On the other hand, most of the dose occurs at energies below the effective threshold NTA film. (author)

Stable Chemical Dosimeters for Partial Reconstruction of Nuclear Accident Conditions

Energy Technology Data Exchange (ETDEWEB)

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

1969-10-15

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

Fast fluence measurement for JOYO irradiation field using niobium dosimeter

International Nuclear Information System (INIS)

Ito, Chikara

2004-03-01

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

Current situation for exoelectron dosimeters of BeO ceramic in neutron dosimetry

International Nuclear Information System (INIS)

Gammage, R.B.

1977-01-01

Much of the early enthusiasm for using exoelectron dosimeters (ceramic BeO Thermalox 995) in neutron dosimetry was predicted on the belief that the response to fast neutrons, relative to gamma rays, was 0.18 to 0.28 on a R/sub γ/ equiv/tissue rad n/sub f/ basis for neutron energies between 0.1 and 16 MeV. Pairs of BeO disks had to be used, one covered with a polyethylene radiator for producing recoil protons, and the other covered with Teflon. More recent studies indicated a considerably lower ratio of 0.11 for Health Physics Reactor Research fission neutrons. In the earlier work the BeO was coated with gold to enhance the surface conductivity during reading of the thermally stimulated exoelectron emission (TSEE). No metallic coating is now deemed to be necessary. Perhaps thermal neutron contamination of the fast neutron beams due to some thermalization within the hydrogenous radiator was sufficient to cause the high apparent fast neutron sensitivity via n, γ reactions. Whatever the cause, however, the lower value of 0.11 has caused a marked subsidence of enthusiasm in this technique of fast neutron monitoring

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

Triton and alpha-particle contribution from LiF converter for neutron dosimeter

CERN Document Server

Camacho, M E; Balcazar, M

1999-01-01

A personnel neutron dosimeter prototype based on chemical and electrochemical etched CR-39 detector, combined with LiF converter, has been calibrated using an ICRP-like phantom, under a heavy-water moderated Californium source neutron spectra; A conversion factor of 1.052+-126 spots cm sup - sup 2 mSv sup - sup 1 was obtained. The sealing properties of the detector holder showed a ten-fold reduction in radon background when it was tested in a high radon atmosphere. A convenient mechanical shock resistance was achieved in LiF converters by sintering to 11 tons pressure LiF powder at 650 deg. C, during one hour.

Personnel neutron dosimetry using electrochemically etched CR-39 foils

International Nuclear Information System (INIS)

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

1986-01-01

A personnel neutron dosimetry system has been developed based on the electrochemical etching of CR-39 plastic at elevated temperatures. The doses obtained using this dosimeter system are more accurate than those obtained using other dosimetry systems, especially when varied neutron spectra are encountered. This Cr-39 dosimetry system does not have the severe energy dependence that exists with albedo neutron dosimeters or the fading and reading problems encountered with NTA film. The dosimetry system employs an electrochemical etch procedure that be used to process large numbers of Cr-39 dosimeters. The etch procedure is suitable for operations where the number of personnel requires that many CR-39 dosimeters be processed. Experience shows that one full-time technician can etch and evaluate 2000 foils per month. The energy response to neutrons is fairly flat from about 80 keV to 3.5 MeV, but drops by about a factor of three in the 13 to 16 MeV range. The sensitivity of the dosimetry system is about 7 tracks/cm 2 /mrem, with a background equivalent to about 8 mrem for new CR-39 foils. The limit of sensitivity is approximately 10 mrem. The dosimeter has a significant variation in directional dependence, dropping to about 20% at 90 0 . This dosimeter has been used for personnel neutron dosimetry at the Lawrence Livermore National Laboratory for more tha 18 months. 6 refs., 23 figs., 2 tabs

Neutron response study

International Nuclear Information System (INIS)

Endres, G.W.R.; Fix, J.J.; Thorson, M.R.; Nichols, L.L.

1981-01-01

Neutron response of the albedo type dosimeter is strongly dependent on the energy of the incident neutrons as well as the moderating material on the backside of the dosimeter. This study characterizes the response of the Hanford dosimeter for a variety of neutron energies for both a water and Rando phantom (a simulated human body consisting of an actual human skeleton with plastic for body muscles and certain organs). The Hanford dosimeter response to neutrons of different energies is typical of albedo type dosimeters. An approximate two orders of magnitude difference in response is observed between neutron energies of 100 keV and 10 MeV. Methods were described to compensate for the difference in dosimeter response between a laboratory neutron spectrum and the different spectra encountered at various facilities in the field. Generally, substantial field support is necessary for accurate neutron dosimetry

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

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

Development of neutron diffuse scattering analysis code by thin film and multilayer film

International Nuclear Information System (INIS)

Soyama, Kazuhiko

2004-01-01

To research surface structure of thin film and multilayer film by neutron, a neutron diffuse scattering analysis code using DWBA (Distorted-Wave Bron Approximation) principle was developed. Subjects using this code contain the surface and interface properties of solid/solid, solid/liquid, liquid/liquid and gas/liquid, and metal, magnetism and polymer thin film and biomembran. The roughness of surface and interface of substance shows fractal self-similarity and its analytical model is based on DWBA theory by Sinha. The surface and interface properties by diffuse scattering are investigated on the basis of the theoretical model. The calculation values are proved to be agreed with the experimental values. On neutron diffuse scattering by thin film, roughness of surface of thin film, correlation function, neutron propagation by thin film, diffuse scattering by DWBA theory, measurement model, SDIFFF (neutron diffuse scattering analysis program by thin film) and simulation results are explained. On neutron diffuse scattering by multilayer film, roughness of multilayer film, principle of diffuse scattering, measurement method and simulation examples by MDIFF (neutron diffuse scattering analysis program by multilayer film) are explained. (S.Y.)To research surface structure of thin film and multilayer film by neutron, a neutron diffuse scattering analysis code using DWBA (Distorted-Wave Bron Approximation) principle was developed. Subjects using this code contain the surface and interface properties of solid/solid, solid/liquid, liquid/liquid and gas/liquid, and metal, magnetism and polymer thin film and biomembran. The roughness of surface and interface of substance shows fractal self-similarity and its analytical model is based on DWBA theory by Sinha. The surface and interface properties by diffuse scattering are investigated on the basis of the theoretical model. The calculation values are proved to be agreed with the experimental values. On neutron diffuse scattering

A new electret dosimeter for fast neutrons

International Nuclear Information System (INIS)

Campos, L.L.; Suarez, A.A.; Mascarenhas, S.

1982-01-01

A new electret for fast-neutron personnel dosimetry is described and calibration curves obtained. Its performance may be improved by changes in the wall composition and geometric parameters. The advantages of electrets over TL and film are the non-erasure of information, low cost, fast reading and portability. (U.K.)

Evaluation of the implementation and use of active personal dosimeters for neutrons in Brazil; Evaluacion de la implementacion y del uso de los dosimetros individuales activos para neutrones en el Brasil

Energy Technology Data Exchange (ETDEWEB)

Castro B, C. P.; Wagner P, W.; De Souza P, K. C., E-mail: karla@ird.gov.br [Instituto de Radioprotecao e Dosimetria, Av. Salvador Allende s/n, Recreio Bandeirantes, 22780-160 Rio de Janeiro (Brazil)

2014-08-15

This work was conducted through of a field research based on a questionnaire sent to users of active personal dosimeters. A retrospective study of the last six years was also carried out of the services in the Neutron Metrology Laboratory (2008-2013) referent to the active personal dosimeters, taking into consideration the standards ISO-8529-3 and IEC-61526. The active personal dosimeters are defined as any instrument of individual monitoring with direct reading capacity, used by individuals exposed to ionizing radiation fields. Through research was verified that the active personal dosimeters work associated with other dosimeter types. Considering all dosimeters declared in the questionnaire, only two dosimeters (MGP brand Dmc 2000-GN model and the brand ATOMTEX model AT2503A) have conformity declaration with the international standard IEC-61526: 2005 reported by the manufacturers. (author)

Comparison between dosimeter films and electronic dosimeters results obtained in F-18 production practices at IEN/CNEN

International Nuclear Information System (INIS)

Paulo, Osvaldir; Carlos, Luiz R.J.; Mendes, Milton

2008-01-01

Full text: The aim of the present work is the comparison of the dose rates values obtained from dosimeter films with the values obtained from electronic dosimeters used by radiological protection technician involved in practices with fluorine-18 production in CV-28 cyclotron at IEN/CNEN. The motivation for this work was the increase on the demand of this radiopharmaceutical. Nowadays there is an increase demand on the number of clinics and hospitals which had started to use the technique of radiodiagnostic using positron-emission tomography (PET). Therefore, the produced radionuclide activities (physics quantity) and also the complexity of the practices of radiological protection in the areas of that facility had increased a lot. The conventional statistical methods will be used to evaluate the results obtained in the analysis of the data obtained in the reading of the dosimeters. This comparative method is however a first step to taking decisions regarding radiological protection service. Therefore that the radiometric surveys of routine are taken in consideration, as well as the information from the technician of radiological protection that is working in those areas. All this data will give support to improve and implement methods and practices on the accelerators' facilities. In addition, the use of these electronic dosimeters will makes possible the technician read these dose rates received immediately during the practices and use these information you make decisions. In case of dose rates values to present above the expected the practice will be ploughed. Another point to be considered is that this work will propitiate the future updates of the procedures designated to those practices and to conduct at the radiological protection optimization. (author)

MONTE CARLO CALCULATION OF THE ENERGY RESPONSE OF THE NARF HURST-TYPE FAST- NEUTRON DOSIMETER

Energy Technology Data Exchange (ETDEWEB)

De Vries, T. W.

1963-06-15

The response function for the fast-neutron dosimeter was calculated by the Monte Carlo technique (Code K-52) and compared with a calculation based on the Bragg-Gray principle. The energy deposition spectra so obtained show that the response spectra become softer with increased incident neutron energy ahove 3 Mev. The K-52 calculated total res nu onse is more nearly constant with energy than the BraggGray response. The former increases 70 percent from 1 Mev to 14 Mev while the latter increases 135 percent over this energy range. (auth)

Electronic dosimeter characteristics and new developments

International Nuclear Information System (INIS)

Thompson, I.M.G.

1999-01-01

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

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

International Nuclear Information System (INIS)

Galindo, S.; Urena-Nunez, F.

1997-01-01

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

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

Characterization of Thymol blue Radiochromic dosimeters for high dose applications

Directory of Open Access Journals (Sweden)

Feras M. Aldweri

2018-03-01

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

Evaluation of a locally manufactured polyester film (Garfilm-EM) as a dosimeter in radiation processing

International Nuclear Information System (INIS)

Bhat, R.M.; Kini, U.R.; Gupta, B.L.

1998-01-01

Locally manufactured 250 μm thick polyester film (Garfilm-EM) was evaluated spectrophotometrically for its dosimetric properties for use as a high dose radiation dosimeter. This film has good clarity, consistent thickness, scratch resistance and is easy to handle. Radiation induced changes in the absorption spectra were analyzed and 340 nm was chosen as the wavelength for absorption measurements. The reproducibility of the response for gamma rays of 60 Co was found to be within ±2%. The effect of post irradiation storage time on the response was also investigated. From the studies carried out, Garfilm-EM has been found to have a good potential as a dosimeter to measure absorbed doses in the range 20 kGy-200 kGy due to its linear dose-response relationship. (author)

Characteristics of radiophotoluminescent glass dosimeters

Energy Technology Data Exchange (ETDEWEB)

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

2001-07-01

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

Diffuse neutron scattering signatures of rough films

International Nuclear Information System (INIS)

Pynn, R.; Lujan, M. Jr.

1992-01-01

Patterns of diffuse neutron scattering from thin films are calculated from a perturbation expansion based on the distorted-wave Born approximation. Diffuse fringes can be categorised into three types: those that occur at constant values of the incident or scattered neutron wavevectors, and those for which the neutron wavevector transfer perpendicular to the film is constant. The variation of intensity along these fringes can be used to deduce the spectrum of surface roughness for the film and the degree of correlation between the film's rough surfaces

Dosimetric evaluation of the Fricke gel dosimeter using the spectrophotometric technique for application in electron and neutron dosimetry

International Nuclear Information System (INIS)

Mangueira, Thyago Fressatti

2009-01-01

In this work the main dosimetric characteristics of the Fricke Xylenol Gel (FXG) solution were established for further application in the measurement of dose distribution of clinical electron fields. The dose-response curves of the FXG in a neutron field were also evaluated for the research in Boron Neutron Capture Therapy (BNCT) and industrial electron fields. The standard reading technique was the spectrophotometric. For the clinical field, the intra and inter-batch reproducibility are better than 1.4% and 5.1 %, respectively, the response presents a linear behavior for doses ranging from 0.2 to 40 Gy independently of the energy and the dose rate in the studied ranges. Due to the effects of the FXG natural oxidation, the optimum elapsed time between FXG preparation and irradiation was established as 24h period and the behavior of the dose-response curve of the FXG using the variation in the absorbance relative to the non-irradiated dosimeter as a basis during the whole studied period were not altered. The dose-response to the industrial electron beam presented an exponential decreasing behavior and the neutron beam for research in BNCT presented a linear behavior for the complete studied dose range. According to the obtained results for the different types of radiation studied for the FXG, there was no change in the position of the characteristic bands of the absorption spectrum due to the interaction of these radiation types. Additional tests were performed to determine the digital photographic imaging of FXG analyses viability and the application of FXG dosimetry on intracavitary brachytherapy. The good performance of the FXG dosimeter in the tests that were carried out indicates that this dosimeter may be applied to the tri-dimensional dose evaluation in radiotherapic treatments using electrons and neutron beams. (author)

Radiological practices using dosimetric films and electronic dosimeters in F-18 production at cyclotron complex center at IEN/CNEN

International Nuclear Information System (INIS)

Santos, Osvaldir P. dos; Silva, J.C.P.; Silva, Luiz Carlos Reina P. da

2009-01-01

The aim of this work is to evaluate, guide and correct radiological practices based on dose rate values obtained from dosimetric films and electronic dosimeters used by technicians involved in Fluorine-18 production facilities at IEN/CNEN. Standard statistical methods have been used to analyze and to evaluate these results. The comparison between these results is the first step to orient decisions concerning radiological practices. Besides, radiometric routine surveys are under evaluation in order to improve radiological control in these facility areas. The electronic dosimeters provide the technicians immediate reading and this help them take protective action immediately. So the comparison between dosimetric film and electronic dosimeters data will provide information about how the recently employed electronic dosimeters are being used and what corrections in their practical use are necessary in order to achieve correct practices. In addition the results and observations obtained will be very important to implement possible changes in radiological routine practices in order to optimize them and keep occupationally exposed individuals radiological dose rates, as low as reasonably achievable, according to ALARA principle. (author)

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

A polymeric dosimeter film based on optically-stimulated luminescence for dose measurements below 1 kGy

International Nuclear Information System (INIS)

Kovacs, A.; Baranyai, M.; Wojnarovits, L.; Slezsak, I.; McLaughlin, W.L.; Miller, S.D.; Miller, A.; Fuochi, P.G.; Lavalle, M.

1999-01-01

A new potential dosimetry system 'Sunna' containing a microcrystalline dispersion of an optically-stimulated fluor in a plastic matrix has been recently developed to measure and image high doses. Our previous investigations have revealed that the new dosimeter system is capable of measuring absorbed doses in the dose range of 1-100 kGy. The optically-stimulated luminescence (OSL) analysis is based on the blue light stimulation of the colour center states produced upon irradiation, and the intensity of the resulting red-light emission is used to measure absorbed dose. This analysis is carried out with a simple table-top fluorimeter developed for this purpose having also the ability to calculate the mathematical formula of the calibration function. The Sunna dosimeter was recently investigated for potential use in lower dose range below 1 kGy. These investigations have shown that the film is suitable for measuring doses in the range of 1-1000 Gy for both electron and gamma radiation. To test the applicability of the film, its reproducibility, stability, sensitivity to ambient and UV light and irradiation temperature were measured. The stability of the dosimeter was investigated by monitoring the change of the OSL signal with storage time after irradiation. Further experiments proved the homogeneity of the film with respect to thickness variation, and limited differences in its response were found between batches. (author)

SEVENTH DOE WORKSHOP ON PERSONNEL NEUTRON DOSIMETRY

Energy Technology Data Exchange (ETDEWEB)

Vallario, E J

1978-10-24

This workshop was the seventh of a series and was held on October 23-24. 1978, at the Central Electricity Generating Board, HQ, London, England. Typically~ attendees at the Workshop were concerned with one of three activities: studying and refining existing techniques in an attempt to quantify already-known parameters with greater precision, looking for ways to apply existing neutron dosirr:etry techniques to a specific local problem, identifying the needs and weaknesses of existing systems, with the goal of improving and passibly simplifying field measurements. The types of neutron dosimetry techniques discussed by participants included albedo dosimeters, track etch, and TLD. One speaker reported on NTA film, noting that fading could be eliminated by drying the emulsion in dry nitrogen before field use. There were no reports on tissue equivalent proportional counters or activation analysis. One participant discussed a metal oxide silicon dosimeter. The need to develop a consistent standard terminology, as well as calibration sources and techniques, on both the national and international level was evident. The need for standardization is particularly acute in the U.S. Techniques for evaluating dosimeter response in the field should he standardized, since several different instruments with widely different response characteristics are currently being used. The choice of instruments is often parochial. Also. the type and use of phantoms should be standardized. Neutron dose assignment is significantly affected by the position of the dosimeter on the body. for example, a typical albedo dosimeter may give differences of up to 20% depending on whether it is worn on the belt or chest. Larger errors are encountered with front-to-back (angular} orientation. 1n an attempt to minimize such errors~ at least two European facilities are using neutron dosimeter belts, which provide dosimeters both in front and in back of the wearer. The gamma-to-neutron ratio around nuclear power

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

International Nuclear Information System (INIS)

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

1991-12-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1991-12-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1991-12-01

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

SSDL Preparation for Implementation of the Use of OSL Dosimeters in Malaysia

International Nuclear Information System (INIS)

Sangau, J.K.; Taiman Kadni; Ahmad Bazlie Abdul Kadir

2013-01-01

Since the early 1980's, film badge has been widely used as a device of personal dose monitoring in Malaysia. Secondary Standard Dosimetry Laboratory (SSDL), as a service center for film badge has obtained the supply of personal monitoring film from Agfa Gevaert, Belgium every year. As the uses of film badge have some weaknesses, it has prompted SSDL to find an alternative dosimeter to replace the film badge. Based on the studies that have been conducted, SSDL has selected OSL dosimeter (Optically Stimulated Luminescent Dosimeter) to replace the film badge and is expected to be fully operational by middle of 2015. This paper aims to explain the selection of OSL dosimeter and planning carried out to ensure the success of their application in Malaysia. (author)

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.

Calibration of dosimeters at 80-120 keV electron irradiation

DEFF Research Database (Denmark)

Miller, A.; Helt-Hansen, J.

to calibrate thin-film dosimeters (Risø B3 and alanine films) by irradiation at the 80–120 keV electron accelerators. This calibration was compared to a 10MeV calibration, and we show that the radiation response of the dosimeter materials (the radiation chemical yield) is constant at these irradiation energies....... However, dose gradients within the dosimeters, when it is irradiated at low electron energies,mean that calibration function here will depend on both irradiation energy and the required effective point of measurement of the dosimeter. These are general effects that apply to any dosimeter that has a non...

Some aspects of the use of proton recoil proportional counters for fast neutron personnel dosimeters

International Nuclear Information System (INIS)

Yule, T.J.; Bennett, E.F.

1984-01-01

Gas-filled proton recoil proportional counters have been used extensively for the measurement of neutron spectra in degraded fission-spectrum environments. Some considerations relating to the use of these counters for personnel dosimetry are here described. High sensitivity and good accuracy in the determination of dose-equivalent can be obtained if relatively high pressure hydrogen-filled proportional counters are used as the active element in a dosimeter system

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.

Track-etch dosemeter response to neutrons up to 300 MeV

International Nuclear Information System (INIS)

Devine, R.T.; Walker, S.; Staples, P.; Duran, M.; Mundis, R.; Miller, J.

1996-01-01

Electro-chemical and chemical track-etch dosemeters were obtained from commercial suppliers and exposed to neutrons produced at the LANTF WNR white neutron source at 15 degree with no shielding and filtered by polyethylene blocks of 2.5, 5.1, 10.2, 20.3 and 40.6 cin thickness. The neutron spectrum was determined using calculations. Mean energies from 28 to 300 MeV were produced. Dose was calculated from the NCRP-38 flux-to-dose conversion. The results are compared with NTA film which was exposed in the same configuration. The response of track etch dosimeters was found to reach a minimum and then rise as the average neutron energy increased. The response of the NTA film increased as the neutron energy increased

Characterization of a new photo-fluorescent film dosimeter for high-radiation dose applications

International Nuclear Information System (INIS)

Murphy, Mark K.; Miller, Steven D.; Kovacs, Andras; Mclaughlin, William L.; Slezsak, Istvan

2001-01-01

Characterization studies on one of the first versions of the Sunna fluorescent dosimeter have been published by Kovacs and McLaughlin. This present study describes testing results of a newer version of the dosimeter (Model and 61543;, batch 0399-20). This dosimeter is a 1-cm by 3-cm polymeric film of 0.5 mm thickness that emits a green fluorescence component at intensities almost linear with dose. The manufacturing method (injection molding) allows potential batch sizes on the order of a million while maintaining a signal precision on the order of+/- 1%. Studies include dose response, dose rate dependence, energy dependence, post-irradiation stability, environmental effects, and variation of response within a batch. Data for both food irradiation and sterilization dose levels were obtained. The results indicate that the green signal (0.3-200 kGy) works well for food irradiation dose levels, especially in refrigerated facilities that maintain tight temperature control. The green signal also works well in sterilization facilities because its irradiation temperature coefficient above room temperature is minimal at sterilization doses. If the user requires readout results in less than 22 hours after room temperature irradiation, the user can either calibrate for a specific post-irradiation readout time(s) or simply heat the dosimeters in a small laboratory oven to quickly stabilize the signal

Characterization of a new photo-fluorescent film dosimeter for high-radiation dose applications

International Nuclear Information System (INIS)

Murphy, M.K.; Miller, S.D.; Kovacs, A.; McLaughlin, W.L.; Slezsak, I.

2002-01-01

Characterization studies on one of the first versions of the Sunna fluorescent dosimeter TM have been published by Kovacs and McLaughlin. This present study describes testing results of a newer version of the dosimeter (Model γ, batch 0399-20). This dosimeter is a 1-cmx3-cm polymeric film of 0.5 mm thickness that emits a green fluorescence component at intensities almost linear with dose. The manufacturing method (injection molding) allows potential batch sizes on the order of a million while maintaining a signal precision on the order of ±1%. Studies include dose response, dose rate dependence, energy dependence, post-irradiation stability, environmental effects, and variation of response within a batch. Data for both food irradiation and sterilization dose levels were obtained. The results indicate that the green signal (0.3-250 kGy) works well for food irradiation dose levels, especially in refrigerated facilities that maintain tight temperature control. The green signal also works well in sterilization facilities because its irradiation temperature coefficient above room temperature is minimal at sterilization doses. If the user requires readout results in <22 h after room temperature irradiation, the user can either calibrate for a specific post-irradiation readout time(s) or simply heat the dosimeters in a small laboratory oven to quickly stabilize the signal

Neutron spectrum survey around the cyclotron of IEN/Brazilian CNEN: calibration of neutron personnel dosemeter

International Nuclear Information System (INIS)

Fajardo, P.W.

1991-01-01

The albedo neutron dosimeter is calibrated directly at the work place due to its high energy dependence. This thesis deals with the study, analysis and application of neutron measurement techniques in order to obtain information about the neutron spectrum and neutron dose equivalent at several representative working places of the cyclotron laboratory of the Nuclear Engineering Institute (IEN). These data are employed mainly in the calibration of the brazilian albedo neutron dosimeter. Bonner spheres and foil activation were used in neutron spectra measurements and the neutron dose equivalents were measured with the single sphere albedo technique. BF 3 and 3 He proportional detectors and 6 LiI scintillation detector were also used in these measurements. The single sphere technique turned out to be more appropriate for neutron dosimetry for calibrating the albedo dosimeter in the varying fields of the cyclotron. Calibration the albedo dosimeter in the varying fields of the cyclotron. Calibration factors were found for routine applications, when the workers are protected by shielding and for radiological accident applications, in the case that a worker is exposed inside the cyclotron room. In all situations the performance of the brazilian albedo dosimeter is compared with that of the german albedo dosimeters. (author)

Development of an alanine dosimeter for gamma dosimetry in mixed environments

International Nuclear Information System (INIS)

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

1992-01-01

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

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.

Personnel neutron dose assessment upgrade: Volume 1, Personnel neutron dosimetry assessment: [Final report

International Nuclear Information System (INIS)

Hadlock, D.E.; Brackenbush, L.W.; Griffith, R.V.; Hankins, D.E.; Parkhurst, M.A.; Stroud, C.M.; Faust, L.G.; Vallario, E.J.

1988-07-01

This report provides guidance on the characteristics, use, and calibration criteria for personnel neutron dosimeters. The report is applicable for neutrons with energies ranging from thermal to less than 20 MeV. Background for general neutron dosimetry requirements is provided, as is relevant federal regulations and other standards. The characteristics of personnel neutron dosimeters are discussed, with particular attention paid to passive neutron dosimetry systems. Two of the systems discussed are used at DOE and DOE-contractor facilities (nuclear track emulsion and thermoluminescent-albedo) and another (the combination TLD/TED) was recently developed. Topics discussed in the field applications of these dosimeters include their theory of operation, their processing, readout, and interpretation, and their advantages and disadvantages for field use. The procedures required for occupational neutron dosimetry are discussed, including radiation monitoring and the wearing of dosimeters, their exchange periods, dose equivalent evaluations, and the documenting of neutron exposures. The coverage of dosimeter testing, maintenance, and calibration includes guidance on the selection of calibration sources, the effects of irradiation geometries, lower limits of detectability, fading, frequency of calibration, spectrometry, and quality control. 49 refs., 6 figs., 8 tabs

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

International Nuclear Information System (INIS)

Aschan, C.

1999-01-01

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

Water-equivalent one-dimensional scintillating fiber-optic dosimeter for measuring therapeutic photon beam

International Nuclear Information System (INIS)

Moon, Jinsoo; Won Jang, Kyoung; Jae Yoo, Wook; Han, Ki-Tek; Park, Jang-Yeon; Lee, Bongsoo

2012-01-01

In this study, we fabricated a one-dimensional scintillating fiber-optic dosimeter, which consists of 9 scintillating fiber-optic dosimeters, septa, and PMMA blocks for measuring surface and percentage depth doses of a therapeutic photon beam. Each dosimeter embedded in the 1-D scintillating fiber-optic dosimeter is composed of square type organic scintillators and plastic optical fibers. Also black PVC films are used as septa to minimize cross-talk between the scintillating fiber-optic dosimeters. To construct a dosimeter system, a 1-D scintillating fiber-optic dosimeter and a CMOS image sensor were combined with 20 m-length plastic optical fibers. Using the dosimeter system, we measured surface and percentage depth doses of 6 and 15 MV photon beams and compared the results with those of EBT films and an ionization chamber. - Highlights: ► Fabrication of a one-dimensional scintillating fiber-optic dosimeter. ► The one-dimensional scintillating fiber-optic dosimeter has 9 scintillating fiber-optic dosimeters. ► Measurements of surface and percentage depth doses of a therapeutic photon beam. ► The results were compared with those of EBT films and an ionization chamber.

Suitability of CR-39 dosimeters for personal dosimetry around CANDU reactors

International Nuclear Information System (INIS)

Cross, W.G.

1992-08-01

The capabilities and limitations of CR-39 damage track detectors have been evaluated for their use as personal neutron dosimeters around CANDU reactors. Since the energy response is a critical characteristic, the neutron energy spectra expected within CANDU containments were studied. In the boiler rooms, around the moderator cooling systems, and in most of the fueling machine vaults, the spectra vary considerably, but the majority of the dose is expected to be delivered by neutrons above 80 keV, the approximate threshold for electrochemically-etched CR-39 detectors. In the Pickering A fueling machine vault, and in areas in other stations to which neutrons from reactors have been multiply scattered, lower energy neutrons may be important. In nearly all areas where people work, it appears that working times will be limited by gamma rays rather than by neutrons. The characteristics of other neutron dosimeters - bubble and superheated drop detectors, albedo detectors, and Si real-time detectors - were also reviewed. For workers who typically receive neutron doses that are small compared with regulatory limits, CR-39 is the most suitable available dosimeter for demonstrating compliance. All single dosimeters have poor angular response over the range 0 to 180 degrees because of the shielding of the body. Albedo and Si detectors have particularly poor energy responses over the energy range of importance. Bubble and superheated drop detectors have the advantages of immediate readout and high sensitivity, but the disadvantages of inability to integrate doses over a long period, temperature dependence, very limited range and higher cost. (Author) (110 refs., 45 figs.)

Studies and applications of neutron radiography with film methods

International Nuclear Information System (INIS)

Ikeda, Yasushi

1989-01-01

Neutron radiography has been studied with film methods and applied to some industrial applications. The film methods include not only conventional silver-halide emulsion films, such as industrial, medical or soft X-ray ones, but also track-etch films and those for indirect methods. The characteristics of the film methods are analyzed and investigated with using various image converters, such as gadolinium metal foil and evaporation films, or some scintillation converters such as NE426. The sensitivities and MTFs for various sets of films and converters have been obtained, which gives a chart of the correlation between the appropriate exposure and resolving powers for them. From the chart, one can select some proper sets for the purpose and given conditions of neutron radiography facilities. The film methods have been applied to inspect very fine cracks in thick steel blocks and plates. It is also applied to observe nuclear fuel pellets or irradiated nuclear fuel pins. Furthermore, the film method has been used for neutron computed tomography. Very fine Eu-particles in TiO pellets, which diameters are nearly 300 micron, can be reconstructed by the neutron CT. The fine neutron CT will be useful for the inspection of Pu-particles in mixed oxide nuclear fuel pellets for future advance nuclear reactors. (author)

Optical properties of poly(2,6-dimethyl-1,4-phenylene oxide) film and its potential for a long-term solar ultraviolet dosimeter

International Nuclear Information System (INIS)

Lester, R A; Parisi, A V; Kimlin, M G; Sabburg, J

2003-01-01

The optical properties of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) film have been characterized in order to develop an alternative method for UV dosimetry with a focus on long-term human exposure measurements. The dynamic range of PPO film was found to extend to 2 MJ m -2 of broadband UV exposure independently of film thickness, providing an exposure range of roughly four summer days at subtropical latitudes. The sensitivity of the film to UV exposure was positively related to film thickness in the 20-40 μm range. Films of 40 μm thickness proved to be the most suitable for long-term human UV exposure measurements. The temperature independence of the response of 40 μm PPO film was established from 1.5 deg. C to 50 deg. C within a dosimeter response uncertainty of 6.5%. Dose-rate independence was also demonstrated within 8% of the mean dosimeter response. The spectral response approximates the CIE erythemal action spectrum between 300 and 340 nm, with a peak response at 305 nm. A large deviation from this action spectrum was observed at shorter wavelengths. Investigation of the angular response in both the azimuth and altitude planes showed a cosine error of less than 6.2% between 0 deg. and 40 deg., and did not exceed 13.3% at any angle greater than 40 deg. These results indicate that PPO film satisfies the requirements for use as a UV dosimeter, and may be employed in long-term human exposure measurements

High energy neutron dosimeter

International Nuclear Information System (INIS)

Rai, K.S.F.

1994-01-01

A device for measuring dose equivalents in neutron radiation fields is described. The device includes nested symmetrical hemispheres (forming spheres) of different neutron moderating materials that allow the measurement of dose equivalents from 0.025 eV to past 1 GeV. The layers of moderating material surround a spherical neutron counter. The neutron counter is connected by an electrical cable to an electrical sensing means which interprets the signal from the neutron counter in the center of the moderating spheres. The spherical shape of the device allows for accurate measurement of dose equivalents regardless of its positioning. 2 figures

Neutron skyshine measurement at a K1200 superconducting heavy ion cyclotron using bubble dosimeters

Energy Technology Data Exchange (ETDEWEB)

Mukherjee, B. [Safety Div., Australian Nuclear Science and Technology Organisation, Menai (Australia); Ronningen, R.M. [Michigan State Univ., National Superconducting Cyclotron Lab., East Lansing, MI (United States); Rossi, P. [Michigan State Univ., Office of Radiation, Chemical and Biological Safety, East Lansing, MI (United States)

1999-07-01

Understanding the characteristics of the neutron skyshine radiation is necessary for an accurate assessment of the environmental dose in the vicinity of the containment of a high-energy particle accelerator. At the National Superconducting Cyclotron Laboratory (NSCL), neutron skyshine was measured, using beams of 140 MeV/nucleon {sup 4}He and 80 MeV/nucleon {sup 22}Ne ions from the K1200 superconducting cyclotron. After passing through a radioactive-beam production target, the ion beam stopped in a solid aluminium stopping bar inside of a dipole magnet, resulting in the production of high energy fragmentation as well as evaporation neutrons in the NSCL Analysis Hall. The neutron dose equivalent and energy spectrum at the 1.37 m thick concrete roof of the Analysis Hall, directly above the aluminium target bar (reference point), were estimated, using a spherical 'rem-counter' and a set of seven Bonner-spheres, respectively. The skyshine dose, from neutrons transmitted through 21.5-cm local iron 'shielding' of the dipole magnet and the concrete roof, were evaluated using superheated bubble dosimeters at 50 m, 75 m, 100 m and 115 m from the reference point. The neutron doses beyond the extremity of the NSCL facility were extrapolated from the results of this investigation and were used to predict the exposure to members of the public by considering the operation schedule of the K1200 cyclotron. (authors)

Effects of temperature and humidity during irradiation on the response of radiachromic film dosimeters

International Nuclear Information System (INIS)

Ningnoi, T.; Ehlermann, D.A.E.

1994-01-01

The effects of temperature and humidity during γ irradiation on the response of two types of film dosimeters (Far West radiochromic and GafChromic films) were studied in the dose range of 0.3-3 kGy. Both films show a significant effect of temperature and humidity and a simple correction function is proposed. This correction is usually between 5 and 10% for the range studied. For the GafChromic film, a colour change at temperatures above 50 o C was observed and, consequently, this system cannot be used at these temperatures. At lower temperatures down to -70 o C the sensitivity of both films is reduced and a simple correction is possible. In this study and for the dose ranges used, only a slight dependence on humidity was observed for both films from 0 to 60% r.h. Whereas the GafChromic film at humidities up to 90% r.h. shows only a moderate effect, the Far West film shows a considerable inconsistency for the dose range studied. A simple correction function may be applied for humidity effects, except for the Far West film above 60% r.h. where the effect of humidity is also dose dependent. (author)

UVB DNA dosimeters analyzed by polymerase chain reactors

International Nuclear Information System (INIS)

Yoshida, Hiroko; Regan, J.D.; Florida Inst. of Tech., Melbourne, FL

1997-01-01

Purified bacteriophage λ DNA was dried on a UV-transparent polymer film and served as a UVB dosimeter for personal and ecological applications. Bacteriophage λ DNA was chosen because it is commercially available and inexpensive, and its entire sequence is known. Each dosimeter contained two sets of DNA sandwiched between UV-transparent polymer films, one exposed to solar radiation (experimental) and another protected from UV radiation by black paper (control). The DNA dosimeter was then analyzed by a polymerase chain reaction (PCR) that amplifies a 500 base pair specific region of λ DNA. Photoinduced damage in DNA blocks polymerase from synthesizing a new strand; therefore, the amount of amplified product in UV-exposed DNA was reduced from that found in control DNA. The dried λ DNA dosimeter is compact, robust, safe and transportable, stable over long storage times and provides the total UVB dose integrated over the exposure time. (author)

Spin interference of neutrons tunneling through magnetic thin films

International Nuclear Information System (INIS)

Hino, Masahiro; Achiwa, Norio; Tasaki, Seiji; Ebisawa, Toru; Akiyoshi, Tsunekazu; Kawai, Takeshi.

1996-01-01

Larmor precession of a neutron spin is represented as the superposition of the wave functions of the two Stern-Gerlach states ↑ and ↓. A transverse neutron spin echo (NSE) spectrometer can hence be used as a neutron spin interferometer (NSI) by setting a magnetic film, such as iron and permalloy45 (Fe 55 Ni 45 ), thin enough to permit tunneling at an incident angle above and below the critical angle of the total reflection in the Larmor precession field. The NSI can be used to study spin coherent superposition and rotation of the Larmor precession through a magnetic thin film for a tunneling ↑ spin neutron and a non-tunneling ↓ spin neutron and to get the tunneling time using Larmor clock. The NSI experiments were carried out to measure the shifts of NSE signals transmitted through magnetic iron films with thicknesses of 200 and 400 A and those magnetic permalloy45 films with thicknesses of 200 and 400 A, respectively, as a function of the incident angle. Then even in tunneling ↑ spin neutron and non-tunneling ↓ spin neutron, NSE signal was observed. The phase delay was measured in iron and permalloy45 films with thickness of 200 A, and the tunneling time using Larmor clock was estimated to be 4 ± 0.6 x 10 -9 sec. (author)

SU-E-T-75: Commissioning Optically Stimulated Luminescence Dosimeters for Fast Neutron Therapy

Energy Technology Data Exchange (ETDEWEB)

Young, L [UniversityWashington, Seattle, WA (United States); Yang, F; Sandison, G [University of Washington, Seattle, WA (United States); Woodworth, D [University of California, Santa Barbara, Santa Barbara, CA (United States); McCormick, Z [University of Nevada - Reno, Reno, Nevada (United States)

2014-06-01

Purpose: Fast neutrons therapy used at the University of Washington is clinically proven to be more effective than photon therapy in treating salivary gland and other cancers. A nanodot optically stimulated luminescence (OSL) system was chosen to be commissioned for patient in vivo dosimetry for neutron therapy. The OSL-based radiation detectors are not susceptible to radiation damage caused by neutrons compared to diodes or MOSFET systems. Methods: An In-Light microStar OSL system was commissioned for in vivo use by radiating Landauer nanodots with neutrons generated from 50.0 MeV protons accelerated onto a beryllium target. The OSLs were calibrated the depth of maximum dose in solid water localized to 150 cm SAD isocenter in a 10.3 cm square field. Linearity was tested over a typical clinical dose fractionation range i.e. 0 to 150 neutron-cGy. Correction factors for transient signal fading, trap depletion, gantry angle, field size, and wedge factor dependencies were also evaluated. The OSLs were photo-bleached between radiations using a tungsten-halogen lamp. Results: Landauer sensitivity factors published for each nanodot are valid for measuring photon and electron doses but do not apply for neutron irradiation. Individually calculated nanodot calibration factors exhibited a 2–5% improvement over calibration factors computed by the microStar InLight software. Transient fading effects had a significant impact on neutron dose reading accuracy compared to photon and electron in vivo dosimetry. Greater accuracy can be achieved by calibrating and reading each dosimeter within 1–2 hours after irradiation. No additional OSL correction factors were needed for field size, gantry angle, or wedge factors in solid water phantom measurements. Conclusion: OSL detectors are a useful for neutron beam in vivo dosimetry verification. Dosimetric accuracy comparable to conventional diode systems can be achieved. Accounting for transient fading effects during the neutron beam

Problems in the measurement of electron-dose distribution with film dosimeters inserted into solid materials

International Nuclear Information System (INIS)

Okuda, Shuichi; Fukuda, Kyue; Tabata, Tatsuo; Okabe, Shigeru

1981-01-01

On the insertion of film dosimeters into solid materials, thin air gaps are formed. The influence of such gaps on measured profiles of depth-dose distributions was investigated for aluminum irradiated with collimated beams of 15-MeV electrons. Measurements were made by changing the gap width or the incidence angle of the electrons. The present results showed that streaming of incident electrons through the gaps resulted in the appearance of a peak and a minimum in a depth-dose curve measured. This effect was suppressed by the increase of the angle between the film and the electron-beam axis. (author)

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

Science.gov (United States)

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

2018-04-11

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

Performance testing of extremity dosimeters, Study 2

International Nuclear Information System (INIS)

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

1990-04-01

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

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

International Nuclear Information System (INIS)

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

1994-02-01

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

Measurement of relative depth-dose distribution in radiochromic film dosimeters irradiated with 43-70 keV electron beam for industrial application

Science.gov (United States)

Matsui, Shinjiro; Hattori, Takeaki; Nonaka, Takashi; Watanabe, Yuki; Morita, Ippei; Kondo, Junichi; Ishikawa, Masayoshi; Mori, Yoshitaka

2018-05-01

The relative dose in a layer, which is thinner than the thickness of the dosimeter is evaluated using simulated depth-dose distributions, and the measured responses of dosimeters with acceleration voltages from 43 to 70 kV, via ultra-low-energy electron beam (ULEB) irradiation. By stacking thin film dosimeters, we confirmed that the simulated depth-dose distributions coincided with the measured depth-dose curve within the measurement uncertainty (k = 2). Using the measurement dose of the 47 μm dosimeter and the simulated depth-dose distribution, the dose of 11 μm dosimeters in the surface was evaluated within the measurement uncertainty (k = 2). We also verified the effectiveness of this method for a thinner layer by changing the acceleration voltage of the irradiation source. We evaluated the relative dose for an adjusted depth of energy deposition from 4.4 μm to 22.8 μm. As a result, this method was found to be effective for a thickness, which is less than the thickness of the dosimeter. When irradiation conditions are well known with accuracy, using the confirmed relative depth-dose distributions across any dosimeter thickness range, a dose evaluation, in several μm steps will possibly improve the design of industrial ULEB processes.

Automatic dosimeter for kerma measurement based on commercial PIN photo diodes

International Nuclear Information System (INIS)

Kushpil, V.; Kushpil, S.; Huna, Z.

2011-01-01

A new automatic dosimeter for measurement of radiation dose from neutron and ionization radiation is presented. The dosimeter (kerma meter) uses commercial PIN diodes with long base as its active element. Later it provides a maximal dependence of the minority carriers life time versus absorbed dose. The characteristics of the dosimeter were measured for several types of commercial diodes. Device can be useful in many environmental or industrial applications. (authors)

Investigation of self-indicating radiation personal dosimeter

International Nuclear Information System (INIS)

Xia Wen; Ye Honsheng; Lin Min; Xu Lijun; Chen Kesheng; Chen Yizhen

2014-01-01

A self-indicating radiation personal dosimeter was investigated using radiation sensitive material diacetylene monomer PCDA, which was a component of the polymerization system. The substrate material, solvent, sensitive material, solution temperature, thickness of film and the preparation method were studied. The dosimeter colour changes from white to blue when exposed 0.1-2.5 Gy, and the linearly dependent coefficient of the exposure response is 0.9998, the stability of absorbency in two weeks after exposure is testified well. It can be used as self-indicating radiation alert personal dosimeter. (authors)

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

Establishing personal dosimetry procedure using optically stimulated luminescence dosimeters in photon and mixed photon-neutron radiation fields

International Nuclear Information System (INIS)

Le Ngoc Thiem; Bui Duc Ky; Trinh Van Giap; Nguyen Huu Quyet; Ho Quang Tuan; Vu Manh Khoi; Chu Vu Long

2017-01-01

According to Vietnamese Law on Atomic Energy, personal dosimetry (PD) for radiation workers is required periodically in order to fulfil the national legal requirements on occupational radiation dose management. Since the radiation applications have become popular in Vietnamese society, the thermal luminescence dosimeters (TLDs) have been used as passive dosimeters for occupational monitoring in the nation. Together with the quick increase in radiation applications and the number of personnel working in radiation fields, the Optically Stimulated Luminescence Dosimeters (OSLDs) have been first introduced since 2015. This work presents the establishment of PD measuring procedure using OSLDs which are used for measuring photons and betas known as Inlight model 2 OSL (OSLDs-p,e) and for measuring mixed radiations of neutrons, photons and betas known as Inlight LDR model 2 (OSLDs-n,p,e). Such following features of OSLDs are investigated: detection limit, energy response, linearity, reproducibility, angular dependency and fading with both types of OSLDs-p,e and OSLDs-n,p,e. The result of an intercomparison in PD using OSLDs is also presented in the work. The research work also indicates that OSL dosimetry can be an alternative method applied in PD and possibly become one of the most popular personal dosimetry method in the future. (author)

Methods for Probing Magnetic Films with Neutrons

Science.gov (United States)

Kozhevnikov, S. V.; Ott, F.; Radu, F.

2018-03-01

We review various methods in the investigation of magnetic films with neutrons, including those based on the effects of Larmor precession, Zeeman spatial splitting of the beam, neutron spin resonance, and polarized neutron channeling. The underlying principles, examples of the investigated systems, specific features, applications, and perspectives of these methods are discussed.

B{sub 4}C thin films for neutron detection

Energy Technology Data Exchange (ETDEWEB)

Hoeglund, Carina [European Spallation Source ESS AB, P.O. Box 176, SE-221 00 Lund (Sweden); Department of Physics, Chemistry and Biology (IFM), Thin Film Physics Division, Linkoeping University, SE-581 83 Linkoeping (Sweden); Birch, Jens; Jensen, Jens; Hultman, Lars [Department of Physics, Chemistry and Biology (IFM), Thin Film Physics Division, Linkoeping University, SE-581 83 Linkoeping (Sweden); Andersen, Ken; Hall-Wilton, Richard [European Spallation Source ESS AB, P.O. Box 176, SE-221 00 Lund (Sweden); Bigault, Thierry; Buffet, Jean-Claude; Correa, Jonathan; Esch, Patrick van; Guerard, Bruno; Piscitelli, Francesco [Institute Laue Langevin, Rue Jules Horowitz, FR-380 00 Grenoble (France); Khaplanov, Anton [European Spallation Source ESS AB, P.O. Box 176, SE-221 00 Lund (Sweden); Institute Laue Langevin, Rue Jules Horowitz, FR-380 00 Grenoble (France); Vettier, Christian [European Spallation Source ESS AB, P.O. Box 176, SE-221 00 Lund (Sweden); European Synchrotron Radiation Facility, BP 220, FR-380 43 Grenoble Cedex 9 (France); Vollenberg, Wilhelmus [Vacuum, Surfaces and Coatings Group (TE/VSC), CERN, CH-1211 Geneva 23 (Switzerland)

2012-05-15

Due to the very limited availability of {sup 3}He, new kinds of neutron detectors, not based on {sup 3}He, are urgently needed. Here, we present a method to produce thin films of {sup 10}B{sub 4}C, with maximized detection efficiency, intended to be part of a new generation of large area neutron detectors. B{sub 4}C thin films have been deposited onto Al-blade and Si wafer substrates by dc magnetron sputtering from {sup nat}B{sub 4}C and {sup 10}B{sub 4}C targets in an Ar discharge, using an industrial deposition system. The films were characterized with scanning electron microscopy, elastic recoil detection analysis, x-ray reflectivity, and neutron radiography. We show that the film-substrate adhesion and film purity are improved by increased substrate temperature and deposition rate. A deposition rate of 3.8 A/s and substrate temperature of 400 deg. C result in films with a density close to bulk values and good adhesion to film thickness above 3 {mu}m. Boron-10 contents of almost 80 at. % are obtained in 6.3 m{sup 2} of 1 {mu}m thick {sup 10}B{sub 4}C thin films coated on Al-blades. Initial neutron absorption measurements agree with Monte Carlo simulations and show that the layer thickness, number of layers, neutron wavelength, and amount of impurities are determining factors. The study also shows the importance of having uniform layer thicknesses over large areas, which for a full-scale detector could be in total {approx}1000 m{sup 2} of two-side coated Al-blades with {approx}1 {mu}m thick {sup 10}B{sub 4}C films.

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

Dose intercomparison for 400–500 keV electrons using FWT-60 film and glutamine (spectrophotometric readout) dosimeters

DEFF Research Database (Denmark)

Gupta, B. L.; Nilekani, S. R.; Gehringer, P.

1986-01-01

This paper describes the dose and the depth dose measurements with FWT-60 film and glutamine (Spectrophotometric readout) dosimeters for 400–500 keV electrons. The glutamine powder was spread uniformly in polyethylene bags and the powder thickness in each bag was 5 mg cm−2. Both techniques show...

Magnetic neutron diffraction of MnO thin films

International Nuclear Information System (INIS)

Neubeck, W.; Vettier, C.; Mannix, D.; Bernhoeft, N.; Hiess, A.; Ranno, L.; Givord, D.

1999-01-01

We report on magnetic neutron diffraction carried out on various epitaxial MnO(III) thin films grown on sapphire and MgO substrates. In all samples, of masses between 5 and 50 μg, magnetic Bragg peaks have been observed. The films exhibit what appears to be continuous phase-transitions in contrast to the strongly discontinuous transition exhibited by bulk samples. In addition, the Neel temperature of films prepared on sapphire substrates is strongly enhanced above that of the bulk whilst that of the film grown on MgO is depressed. The possibility to measure magnetic excitations in such thin film systems is discussed in the light of promising test results obtained from an inelastic magnetic neutron scattering experiment on the IN8 spectrometer. (authors)

Neutron Measurements At Hanford's Plutonium Finishing Plant

International Nuclear Information System (INIS)

Conrady, Matthew M.; Berg, Randal K.; Scherpelz, Robert I.; Rathbone, Bruce A.

2009-01-01

The Pacific Northwest National Laboratory (PNNL) conducted neutron measurements at Hanford's Plutonium Finishing Plant (PFP). The measurements were performed to evaluate the performance of the Hanford Standard Dosimeter (HSD) and the 8816 TLD component of the Hanford Combination Neutron Dosimeter (HCND) in the neutron fields responsible for worker neutron exposures. For this study, TEPC detectors and multisphere spectrometers were used to measure neutron dose equivalent rate, and multispheres were used to measure average neutron energy. Water-filled phantoms holding Hanford dosimeters were positioned at each measurement location. The phantoms were positioned in the same location where a multisphere measurement was taken and TEPCs were also positioned there. Plant survey meters were also used to measure neutron dose rates at all locations. Three measurement locations were chose near the HC-9B glovebox in room 228A of Building 234-5. The multisphere spectrometers measured average neutron energies in the range of 337 to 555 keV at these locations. Personal dose equivalent, Hp(10)n, as measured by the multisphere and TEPC, ranged from 2.7 to 9.7 mrem/h in the three locations. Effective dose assuming a rotational geometry (EROT) was substantially lower than Hp(10), ranging from 1.3 to 3.6 mrem/h. These values were lower than the reported values from dosimeters exposed on a rotating phantom. Effective dose assuming an AP geometry (EAP) was also substantially lower than Hp(10), ranging from 2.3 to 6.5 mrem/h. These values were lower than the reported values from the dosimeters on slab phantoms. Since the effective dose values were lower than reported values from dosimeters, the dosimeters were shown to be conservative estimates of the protection quantities.

Setting-Up of a Neutron Dosimeter Using Ionographic Tracks in an Insulating Solid; Realisation d'un Dosimetre a Neutrons Utilisant les Traces Ionographiques dans un Solide Isolant

Energy Technology Data Exchange (ETDEWEB)

Carfi, N.; Dugnani Lonati, R.; Mangialajo, M. [Centro Informazioni Studi Esperienze, Segrate, Milan (Italy)

1971-06-15

The use of dielectrics such as mica, glasses and plastic materials for charged particle track recording has been developed in the past years; track recording of fission fragments produced in fissile materials under neutron irradiation is particularly interesting. The method has not as yet been applied to neutron dosimetry owing to the difficulties of track observation and counting using optical microscopes. A method has recently been proposed which results in markedly reduced counting times, electronic counting of the electric discharges between two electrodes through the dielectric which was perforated by the fission fragments. The reasons for adopting this new technique to set-up a neutron dosimeter are: (a) economic advantages, since a rather simple electronic instrumentation will give a reading of the dosimeter, preparation of which can be carried out immediately and at a modest cost; (b) fast reading, since the response can be obtained in less than two hours from irradiation; (c) dosimetric advantages owing to the lack of fading and insensitivity to {beta} or {gamma} radiations. The present work describes the method adopted and the equipment used to set up the dosimeter. Results are reported and briefly discussed. (author) [French] Au cours des dernieres annees on a assiste a un developpement remarquable de l' utilisation d' isolants tels que le mica, les verres et les materiaux plastiques pour l' enregistrement des traces de particules chargees; l' enregistrement des traces de fragments de fission produits dans les materiaux fissiles sous irradiation neutronique est particulierement interessant. Cette methode n'a pas, jusqu a present, ete appliquee a la dosimetrie des neutrons a cause des difficultes que presentent l' observation et le comptage des traces au microscope optique. On a propose recemment une methode qui permet de reduire considerablement la duree de l' operation en comptant electroniquement les decharges electriques qui se produisent entre deux

Preliminary experiment of fast neutron imaging with direct-film method

International Nuclear Information System (INIS)

Pei Yuyang; Tang Guoyou; Guo Zhiyu; Zhang Guohui

2005-01-01

A preliminary experiment is conducted with direct-film method under the condition that fast neutron is generated by the reaction of 9 Be(d, n) on the Beijing University 4.5 MV Van de Graaff, whose energy is lower than 7 MeV. Basic characteristics of direct-film neutron radiography system are investigated with the help of samples in different materials, different thickness and holes of different diameter. The fast neutron converter, which is vital for fast neutron imaging, is produced with the materials made in China. The result indicates that fast neutron converter can meet the requirement of fast neutron imaging; further research of fast neutron imaging can be conducted on the accelerator and neutron-generator in China. (authors)

Effects of additives and impurities on the properties of CR-39 neutron dosimeters

International Nuclear Information System (INIS)

Tarle, G.

1982-01-01

Several problems have plagued users of commercial CR-39 for neutron dosimetry work. Large variations in sensitivity have been observed in samples received from different manufacturers, from different batches from the same manufacturer and even within a given sheet. The latter variations have taken several forms. Clear etching regions of lower sensitivity near the gasket and sometimes extending well away from the gasket in drip-like patterns have been observed. Large demarcated patches of differing sensitivity and sensitivity variations with depth have been found in many commercial samples of CR-39. In addition, we have observed a general roughening of the post-etch surface and a patchiness of bulk etching associated with contact patterns of adjacent sheets, which have been stored for extended (greater than or equal to 6 mos) periods of time. All of these problems combine to make commercially available CR-39 unreliable as a neutron dosimeter. In an attempt to identify and correct the causes of these problems, a systematic study of the effects of additives, impurities and manufacturing conditions on the uniformity of CR-39 track detectors has been undertaken, and is reported in this paper

A feasibility study using radiochromic films for fast neutron 2D passive dosimetry

International Nuclear Information System (INIS)

Brady, Samuel L; Fallin, Brent; Gunasingha, Rathnayaka; Yoshizumi, Terry T; Howell, Calvin R; Crowell, Alexander S; Tonchev, Anton P; Dewhirst, Mark W

2010-01-01

The objective of this paper is threefold: (1) to establish sensitivity of XRQA and EBT radiochromic films to fast neutron exposure; (2) to develop a film response to radiation dose calibration curve and (3) to investigate a two-dimensional (2D) film dosimetry technique for use in establishing an experimental setup for a radiobiological irradiation of mice and to assess the dose to the mice in this setup. The films were exposed to a 10 MeV neutron beam via the 2 H(d,n) 3 He reaction. The XRQA film response was a factor of 1.39 greater than EBT film response to the 10 MeV neutron beam when exposed to a neutron dose of 165 cGy. A film response-to-soft tissue dose calibration function was established over a range of 0-10 Gy and had a goodness of fit of 0.9926 with the calibration data. The 2D film dosimetry technique estimated the neutron dose to the mice by measuring the dose using a mouse phantom and by placing a piece of film on the exterior of the experimental mouse setup. The film results were benchmarked using Monte Carlo and aluminum (Al) foil activation measurements. The radiochromic film, Monte Carlo and Al foil dose measurements were strongly correlated, and the film within the mouse phantom agreed to better than 7% of the externally mounted films. These results demonstrated the potential application of radiochromic films for passive 2D neutron dosimetry.

Sensitive silicon PIN-diode dosimeter for fast neutrons and method to control and increase its sensitivity

International Nuclear Information System (INIS)

Swinehart, P.R.; Swartz, J.M.

1978-01-01

With the personnel dosimeter, applicable e.g. in medicine, a dose of 0.1 rad for neutrons with an energy greater than 10 keV can be detected. In the range between 0.1 and 20 rad sensitivity is increased to 5 mV/rad. This sensitivity can be achieved by distributing the mass of the semiconductor material of the diode or equal to four times the reciprocal base width. Appropriate dimensions are 750 μm for the edge length of the end surface resp. diameter and 750 μm up to 5000 μm for the base width. (DG) [de

Dose measurement during defectoscopic work using electronic personal dosimeters

International Nuclear Information System (INIS)

Smoldasova, J.

2008-01-01

Personal monitoring of the external radiation of radiation, personnel exposed to sources of ionizing radiation at a workplace is an important task of the radiological protection. Information based on the measured quantities characterizing the level of the exposure of radiation personnel enable to assess the optimum radiological protection at the relevant workplace and ascertain any deviation from the normal operation in time. Different types of personal dosimeters are used to monitor the external radiation of radiation personnel. Basically, there are two types of dosimeters, passive and active (electronic). Passive dosimeters provide information on the dose of exposure after its evaluation, while electronic dosimeters provide this information instantly. The goal of the work is to compare data acquired during different working activities using the DMC 2000 XB electronic dosimeters and the passive film dosimeters currently used at the defectoscopic workplace. (authors)

Operational aspects of the direct ion storage dosimeter system: 18 months of experience at CERN

International Nuclear Information System (INIS)

Carbonez, P.; Kotamaki, E.; Otto, Th.

2006-01-01

CERN, the European Organization for Nuclear Research, operates a dosimetry service for external exposure. The service monitors approximately 5000 Staff, scientific visitors and contractors personnel working on the organizations sites with personal dosimeters for personal dose equivalent (Hp(10), Hp(0.07)) from gamma, beta and neutron radiation. The dosimetry service is approved by the Swiss Federal Health Office, the competent authority for radiation protection. In 2004, the R.A.D.O.S. D.I.S. -1 dosemeter has been introduced to CERN as a gamma-beta dosemeter. Technical characteristics of this dosimeter, based on the direct ion storage technology, are high sensitivity, excellent linearity of the personal dose response with respect to radiation energy or dose, and long-term physical storage of personal dose-related information without the risk of fading. One important technical feature of the dosemeter is its 'instant reading' capability: the user himself can evaluate the received personal dose nondestructively on specific reader stations. This information is digitized, centralized by the CERN-wide network and stored in a database. The consequence of the 'instant reading' capability is a break with in the traditional organisation of a dosimetry service. The personal dosimeters are no longer exchanged periodically for evaluation, but a monthly value of personal dose is calculated from the readings initiated by the user. After a wearing period of one year, users are invited to exchange the dosimeter against a new, recently calibrated unit. The introduction of the D.I.S.-1 dosimeter has profoundly changed the type of work in CERN dosimetry service. Technical and laboratory work (development of film dosimeters, densitometric evaluation) have made place for computer-based procedures and database management. (authors)

Perfection of the individual photographic emulsion dosimeter

International Nuclear Information System (INIS)

Soudain, G.

1960-01-01

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

Neutron dosimetry in containment of a pressurized water reactor utilizing the Panasonic UD-802 dosimetry system

International Nuclear Information System (INIS)

Kralick, S.C.

1984-01-01

The Panasonic UD-802 dosimeter was evaluated as a potential neutron dosimeter for use in containment of a PWR. The Panasonic UD-802 dosimeter, although designed as a beta and gamma dosimeter, is also sensitive to neutrons. UD-802 dosimeters were mounted on polyethylene phantoms and irradiated to known doses at selected locations in containment. The known neutron dose equivalents were determined based on remmeter dose rate measurements and stay times. The thermoluminescent response of the dosimeters and the known neutron dose equivalents were used to obtain a calibration factor at each location. The average calibration factor was 3.7 (unit of dosimeter response per mrem) and all calibration factors were within +-30% of this mean value. The dosimeter distance from the phantom was found to have minimal effect on the response but the system was directionally dependent, necessitating a correction in the calibration factor. The minimum significant dosimeter response was determined independent of any calibration factor. The minimum significant response of the UD-802 to neutrons is a function of the corresponding gamma exposure rate. It is concluded that the Panasonic UD-802 dosimeter can be used for neutron dosimetry in PWR containment

DOE personnel neutron dosimetry evaluation and upgrade program

International Nuclear Information System (INIS)

Faust, L.G.; Stroud, C.M.; Vallario, E.J.

1988-01-01

The US Department of Energy (DOE) sponsors an extensive research program to improve the methods, dosimeters, and instruments available to DOE facilities for measuring neutron dose and assessing its effects on the work force. The Total Dose Meter was recently developed for measuring in real time the absorbed dose of mixed neutron and gamma radiation and for calculating the dose equivalent. The Field Neutron Spectrometer was developed to provide a portable instrument for determining neutron spectra in the workplace for flux-to-dose equivalent conversion and quality factor calculation. The Combination Thermoluminescence/Track Etch Dosimeter (TLD/TED) was developed to extend the effective neutron energy range of the conventional TLDs to improve detection of fast-energy neutrons. An Optically Stimulated Luminescence Dosimeter is presently being developed for application to gamma, neutron, and beta radiation. An Effective Dose Equivalent System is being developed to provide guidance in implementing the January 1987 Presidential Directive to determine effective dose equivalent. Superheated Drop Detectors are being investigated for their potential as real time neutron dosimeters. This paper includes discussions of these improvements brought about by the DOE research program

Transparent lithiated polymer films for thermal neutron detection

Energy Technology Data Exchange (ETDEWEB)

Mabe, Andrew N., E-mail: andrew.n.mabe@gmail.com [Department of Chemistry, University of Tennessee, Knoxville, TN 37996 (United States); Auxier, John D. [Department of Chemistry, University of Tennessee, Knoxville, TN 37996 (United States); Urffer, Matthew J. [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Penumadu, Dayakar [Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Schweitzer, George K. [Department of Chemistry, University of Tennessee, Knoxville, TN 37996 (United States); Miller, Laurence F. [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN 37996 (United States)

2013-09-11

Novel water-soluble {sup 6}Li loaded copolymer scintillation films have been designed and fabricated to detect thermal neutrons. Styrene and maleic anhydride were copolymerized to form an alternating copolymer, then the anhydride functionality was hydrolyzed using {sup 6}Li hydroxide. The resulting poly(styrene-co-lithium maleate) was mixed with salicylic acid as a fluor and cast as a thin film from water. The maximum {sup 6}Li loading obtained that resulted in a transparent film was 4.36% by mass ({sup 6}Li to polymer). The optimum fluorescence output was obtained for 11.7% salicylic acid by mass, presumably in the form of lithium salicylate, resulting in an optimum film containing 3.85% by mass of {sup 6}Li. A facile and robust synthesis method, film fabrication protocol, photoluminescence results, and scintillation responses are reported herein. -- Highlights: • A transparent polymer scintillator containing 3.85 wt% {sup 6}Li has been synthesized. • This class of polymeric thermal neutron scintillation detector is water-soluble. • Salicylic acid, presumably in the form of lithium salicylate, is used as a fluor. • The material emits 373 photons/α ({sup 241}Am) and an average of 139 photons/β ({sup 36}Cl). • The material emits 360 photons per thermal neutron capture event.

Thermal neutron imaging through XRQA2 GAFCHROMIC films coupled with a cadmium radiator

Energy Technology Data Exchange (ETDEWEB)

Sacco, D. [INFN – LNF, Via E. Fermi n.40, Frascati, 00044 Roma (Italy); INAIL – DIT, Via di Fontana Candida n.1, 00040 Monteporzio Catone (Italy); Bedogni, R., E-mail: roberto.bedogni@lnf.infn.it [INFN – LNF, Via E. Fermi n.40, Frascati, 00044 Roma (Italy); Bortot, D. [Politecnico di Milano, Dipartimento di Energia, Via La Masa 34, 20156 Milano (Italy); INFN – Milano, Via Celoria16, 20133 Milano (Italy); Palomba, M. [ENEA Casaccia, Via Anguillarese, 301, S. Maria di Galeria, 00123 Roma (Italy); Pola, A. [Politecnico di Milano, Dipartimento di Energia, Via La Masa 34, 20156 Milano (Italy); INFN – Milano, Via Celoria16, 20133 Milano (Italy); Introini, M.V.; Lorenzoli, M. [Politecnico di Milano, Dipartimento di Energia, Via La Masa 34, 20156 Milano (Italy); Gentile, A. [INFN – LNF, Via E. Fermi n.40, Frascati, 00044 Roma (Italy); Strigari, L. [Laboratory of Medical Physics, Regina Elena National Cancer Institute, Via E. Chianesi 53, 00144 Roma (Italy); Pressello, C. [Department of Medical Physics, Azienda Ospedaliera San Camillo Forlanini, Circonvallazione Gianicolense 87, 00152 Roma (Italy); Soriani, A. [Laboratory of Medical Physics, Regina Elena National Cancer Institute, Via E. Chianesi 53, 00144 Roma (Italy); Gómez-Ros, J.M. [INFN – LNF, Via E. Fermi n.40, Frascati, 00044 Roma (Italy); CIEMAT, Av. Complutense 40, 28040 Madrid (Spain)

2015-10-21

A simple and inexpensive method to perform passive thermal neutron imaging on large areas was developed on the basis of XRQA2 GAFCHROMIC films, commonly employed for quality assurance in radiology. To enhance their thermal neutron response, the sensitive face of film was coupled with a 1 mm thick cadmium radiator, forming a sandwich. By exchanging the order of Cd filter and sensitive film with respect to the incident neutron beam direction, two different configurations (beam-Cd-film and beam-film-Cd) were identified. These configurations were tested at thermal neutrons fluence values in the range 10{sup 9}–10{sup 10} cm{sup −2}, using the ex-core radial thermal neutron column of the ENEA Casaccia – TRIGA reactor. The results are presented in this work.

Performance improvement of pentacosa-diynoic acid label dosimeter for radiation processing technology

Science.gov (United States)

Abdel-Fattah, A. A.; Soliman, Y. S.

2017-12-01

A radiation sensitive material, 10,12-pentacosa-diynoic acid (PCDA), was incorporated into polyvinyl butyral (PVB) films to develop indicators/dosimeters for blood and food irradiation. The present study aims to improve the dosimetric performance of these previously prepared dosimeters and to extend their shelf life by the combination of a radical scavenger, propyl gallate (PG), and a UV absorber, tinuvin-p (TP). The X-ray diffraction (XRD) patterns of the dosimeters were analysed and their dosimetric characteristics were investigated by specular reflectance in the visible spectrum range of 400-700 nm. Upon irradiation, the films turn blue exhibiting two main bands around 670 and 620 nm. Their dose-response functions were fitted by a double exponential growth, 5 parameters, equation. Irradiation temperature influences the dosimeter response at 670 nm without causing thermochromic transition up to 50 °C in poly-PCDA. The useful dose range is 5-4000 Gy depending on the wavelengths of analysis and PCDA content in the films. The overall uncertainty of dose measurement is less than 6% at 2σ.

Development and implementation of a fast neutron monitoring system based on plastic track detectors

International Nuclear Information System (INIS)

Bradley, R.P.; Ryan, R.N.

1988-01-01

The Bureau of Radiation and Medical devices has provided neutron dosimetry services for Canadian industrial and research applications since the late 1960's. The program used a nuclear emulsion film, Kodak NTA, as the personal dosimeter. Despite its two principle shortcomings, that of a relatively high energy threshold, approximately 700 keV, and highly labor intensive analysis technique, there was little else conveniently available for use. For quite a number of years we pursued, as did many laboratories, the possibilities of developing an albedo dosimeter based on paired thermoluminescent elements in some form of cadmium and plastic encapsulation. Some promise has been shown by this method and several major laboratories have designed and are currently using albedo dosimeters. At the first symposium on Personnel Radiation Dosimetry held in Knoxville in 1984, Dale Hankins of the Lawrence Livermore Laboratories, in his paper entitled, Improvements in the Etching of CR-39 for Large Scale Neutron Dosimetry, reported on his laboratories work with the polycarbonate, CR-39. Using this paper as a start and following up on similar work by W. G. Cross at the Chalk River Nuclear Laboratories, we have developed a replacement dosimeter. This paper will describe the principle features of the system introduced into routine use in Canada in October 1987

Assessment of fast and thermal neutron ambient dose equivalents around the KFUPM neutron source storage area using nuclear track detectors

Energy Technology Data Exchange (ETDEWEB)

Fazal-ur-Rehman [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)]. E-mail: fazalr@kfupm.edu.sa; Al-Jarallah, M.I. [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Abu-Jarad, F. [Radiation Protection Unit, Environmental Protection Department, Saudi Aramco, P. O. Box 13027, Dhahran 31311 (Saudi Arabia); Qureshi, M.A. [Center for Applied Physical Sciences, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

2005-11-15

A set of five {sup 241}Am-Be neutron sources are utilized in research and teaching at King Fahd University of Petroleum and Minerals (KFUPM). Three of these sources have an activity of 16Ci each and the other two are of 5Ci each. A well-shielded storage area was designed for these sources. The aim of the study is to check the effectiveness of shielding of the KFUPM neutron source storage area. Poly allyl diglycol carbonate (PADC) Nuclear track detectors (NTDs) based fast and thermal neutron area passive dosimeters have been utilized side by side for 33 days to assess accumulated low ambient dose equivalents of fast and thermal neutrons at 30 different locations around the source storage area and adjacent rooms. Fast neutron measurements have been carried out using bare NTDs, which register fast neutrons through recoils of protons, in the detector material. NTDs were mounted with lithium tetra borate (Li{sub 2}B{sub 4}O{sub 7}) converters on their surfaces for thermal neutron detection via B10(n,{alpha})Li6 and Li6(n,{alpha})H3 nuclear reactions. The calibration factors of NTD both for fast and thermal neutron area passive dosimeters were determined using thermoluminescent dosimeters (TLD) with and without a polyethylene moderator. The calibration factors for fast and thermal neutron area passive dosimeters were found to be 1.33 proton tracks cm{sup -2}{mu}Sv{sup -1} and 31.5 alpha tracks cm{sup -2}{mu}Sv{sup -1}, respectively. The results show variations of accumulated dose with the locations around the storage area. The fast neutron dose equivalents rates varied from as low as 182nSvh{sup -1} up to 10.4{mu}Svh{sup -1} whereas those for thermal neutron ranged from as low as 7nSvh{sup -1} up to 9.3{mu}Svh{sup -1}. The study indicates that the area passive neutron dosimeter was able to detect dose rates as low as 7 and 182nSvh{sup -1} from accumulated dose for thermal and fast neutrons, respectively, which were not possible to detect with the available active neutron

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

International Nuclear Information System (INIS)

Na, Y; Qian, X; Wuu, C; Adamovics, J

2015-01-01

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

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

International Nuclear Information System (INIS)

Faermann, S.

1985-03-01

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

Correlation of Neutron Data Taken at Commercial Nuclear Sites

Energy Technology Data Exchange (ETDEWEB)

Rathbun, L. A.; Endres, G. W.R.

1983-10-01

In this report, data from neutron measurement and dosimetry studies performed by Pacific Northwest Laboratory, the Environmental Measurements Laboratory, and Rensselaer Polytechnic Institute are examined and compared. The purpose of this data correlation effort is to determine whether useful relationships exist between the actual neutron dose equivalent in a typical commercial nuclear power reactor and various measurement parameters, such as ratios of the response of 9-in. to 3-in. spheres, neutron/gamma ratios, albedo dosimeter response and neutron spectrometer readings. In most neutron radiation fields found in the reactors visited, the response of albedo dosimeters can be brought into reasonable agreement with dose equivalents measured with multispheres, tissue equivalent proportional counters (TEPCs) or remmeters. Because the responses of the remmeters, like the responses of albedo dosimeters, are energy dependent, it is preferable to correct the responses of the albedo dosimeters to agree with dose equivalents measured with either TEPCs or multispheres. If one of these laboratory systems has been used to measure neutron dose equivalents at a specific pressurized water reactor, a calculated average albedo dosimeter correction factor can be used for most locations at that reactor. However, if the measured 9-in. to 3-in. remmeter ratio is greater than 0.20, it is advisable to use a plot of 9-in. to 3-in. remmeter ratios versus albedo dosimeter correction factors to obtain an albedo dosimeter correction factor. Because 9-in. to 3-in. remmeter ratios at boiling water reactors are typically greater than 0.20, the latter approach applies to this type of reactor.

Sensitive chemical neutron dosimetry using silver colloids

International Nuclear Information System (INIS)

Brede, O.; Boes, J.; Hoesselbarth, B.

1982-01-01

The radiation-induced formation of silver colloid was checked for its use as a sensitive dosimeter for neutron irradiation. For non-monoenergetic pulsed neutron irradiation in the Dubna IBR-30 reactor, the colloid dosimeter was found to be suitable to indicate the chemical neutron effect, i.e., to determine the sum concentration of the primary particles of water radiolysis: esub(aq)sup(-), OH and H. (author)

Personal fast neutrons dosimetry using radiophotoluminescent glass

International Nuclear Information System (INIS)

Salem, Y. O.; Nachab, A.; Nourreddine, A.; Roy, C.

2013-06-01

In a previous paper we described a new ambient RPL dosimeter that detects fast neutrons in a mixed n-γ field via (n, p) reactions in a polyethylene converter. In the present study, a personal dosimeter is introduced to enable evaluating the individual dose equivalent H p (10) taking into account the albedo. A calibration factor for estimating H p (10) has been determined from the diminishing angular response as the angle of neutron incidence increases to 60 deg from the normal. MCNPX simulations for 241 Am-Be and 252 Cf neutrons, together with a series of monoenergetic neutron beams from 0.144 to 5 MeV, have been used to characterize the dosimeter response, which agrees well with the experimental 241 Am-Be response. (authors)

Neutron diffraction studies of thin film multilayer structures

International Nuclear Information System (INIS)

Majkrzak, C.F.

1985-01-01

The application of neutron diffraction methods to the study of the microscopic chemical and magnetic structures of thin film multilayers is reviewed. Multilayer diffraction phenomena are described in general and in particular for the case in which one of the materials of a bilayer is ferromagnetic and the neutron beam polarized. Recent neutron diffraction measurements performed on some interesting multilayer systems are discussed. 70 refs., 5 figs

Evaluation of optical fibres as gamma radiation dosimeter

International Nuclear Information System (INIS)

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

2005-01-01

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

Neutron reflectivity of electrodeposited thin magnetic films

International Nuclear Information System (INIS)

Cooper, Joshaniel F.K.; Vyas, Kunal N.; Steinke, Nina-J.; Love, David M.; Kinane, Christian J.; Barnes, Crispin H.W.

2014-01-01

Highlights: • Electrodeposited magnetic bi-layers were measured by polarised neutron reflectivity. • When growing a CoNiCu alloy from a single bath a Cu rich region is initially formed. • This Cu rich region is formed in the first layer but not subsequent ones. • Ni deposition is inhibited in thin film growth and Co deposits anomalously. • Alloy magnetism and neutron scattering length give a self-consistent model. - Abstract: We present a polarised neutron reflectivity (PNR) study of magnetic/non-magnetic (CoNiCu/Cu) thin films grown by single bath electrodeposition. We find that the composition is neither homogeneous with time, nor consistent with bulk values. Instead an initial, non-magnetic copper rich layer is formed, around 2 nm thick. This layer is formed by the deposition of the dilute, but rapidly diffusing, Cu 2+ ions near the electrode surface at the start of growth, before the region is depleted and the deposition becomes mass transport limited. After the region has been depleted, by growth etc., this layer does not form and thus may be prevented by growing a copper buffer layer immediately preceding the magnetic layer growth. As has been previously found, cobalt deposits anomalously compared to nickel, and even inhibits Ni deposition in thin films. The layer magnetisation and average neutron scattering length are fitted independently but both depend upon the alloy composition. Thus these parameters can be used to check for model self-consistency, increasing confidence in the derived composition

Evaluation of neutron dosimetry techniques for well-logging operations

International Nuclear Information System (INIS)

Cummings, F.M.; Haggard, D.L.; Endres, G.W.R.

1985-07-01

Neutron dose and energy spectral measurements from 241 AmBe and a 14 MeV neutron generator were performed at a well-logging laboratory. The measurement technique included the tissue equivalent proportional counter, multisphere, two types of remmeters and five types of personnel neutron dosimeters. Several source configurations were used to attempt to relate data to field situations. The results of the measurements indicated that the thermoluminescent albedo dosimeter was the most appropriate personnel neutron dosimeter, and that the most appropriate calibration source would be the source normally employed in the field with the calibration source being used in the unmoderated configuration. 7 refs., 35 figs., 14 tabs

Investigation of water films on fuel rods in boiling water reactors using neutron tomography

Energy Technology Data Exchange (ETDEWEB)

Lanthen, Jonas

2006-09-15

In a boiling water reactor, thin films of liquid water around the fuel rods play a very important role in cooling the fuel, and evaporation of the film can lead to fuel damage. If the thickness of the water film could be measured accurately the reactor operation could be both safer and more economical. In this thesis, the possibility to use neutron tomography, to study thin water films on fuel rods in an experimental nuclear fuel set-up, has been investigated. The main tool for this has been a computer simulation software. The simulations have shown that very thin water films, down to around 20 pm, can be seen on fuel rods in an experimental set-up using neutron tomography. The spatial resolution needed to obtain this result is around 300 pm. A suitable detector system for this kind of experiment would be plastic fiber scintillators combined with a CCD camera. As a neutron source it would be possible to use a D-D neutron generator, which generates neutrons with energies of 2.5 MeV. Using a neutron generator with a high enough neutron yield and a detector with high enough detection efficiency, a neutron tomography to measure thin water films should take no longer than 25 - 30 minutes.

Investigation of water films on fuel rods in boiling water reactors using neutron tomography

International Nuclear Information System (INIS)

Lanthen, Jonas

2006-09-01

In a boiling water reactor, thin films of liquid water around the fuel rods play a very important role in cooling the fuel, and evaporation of the film can lead to fuel damage. If the thickness of the water film could be measured accurately the reactor operation could be both safer and more economical. In this thesis, the possibility to use neutron tomography, to study thin water films on fuel rods in an experimental nuclear fuel set-up, has been investigated. The main tool for this has been a computer simulation software. The simulations have shown that very thin water films, down to around 20 pm, can be seen on fuel rods in an experimental set-up using neutron tomography. The spatial resolution needed to obtain this result is around 300 pm. A suitable detector system for this kind of experiment would be plastic fiber scintillators combined with a CCD camera. As a neutron source it would be possible to use a D-D neutron generator, which generates neutrons with energies of 2.5 MeV. Using a neutron generator with a high enough neutron yield and a detector with high enough detection efficiency, a neutron tomography to measure thin water films should take no longer than 25 - 30 minutes

A new method for the measurement of the polarization characteristics of ferromagnetic films on ultracold neutrons

International Nuclear Information System (INIS)

Taran, Yu.V.

1985-01-01

A new method has been developed for measuring the polarization characteristics of ferromagnetic films on ultracold neutrons (UCN) by single-, double- and triple-transmission of UCN beam through one and the same film. To realize the method an installation has been proposed consisting of the two UCN storage traps connected with a mirror neutron guide. An investigated film is placed in the slit in the middle of the neutron guide. On both sides of the film a spin-flipper is installed bottle is equiped with three neutron values which permit filling in the bottle with UCN and allow oneto let UCN out to the neutron guide or detector. The neutrons once let out from one bottle into the neutron guide are caught by the other. The film can be moved out of the neutron guide or rotated. By manipulating with spin-flippers and the film one may take the integral polarization parameters of the film: transmission, polarizing and analysing efficiencies, so-called S-factor, which is the fourth independent linear combination of the elements of the square 2x2 transmission matrix of the film. The measurement parameters help to restore the film transmission matrix. Then a comparison is drawn with the theoretical models of UCN depolarization on transmission through a ferromagnetic film

Gadolinium oxide coated fully depleted silicon-on-insulator transistors for thermal neutron dosimetry

Energy Technology Data Exchange (ETDEWEB)

Vitale, Steven A., E-mail: steven.vitale@ll.mit.edu; Gouker, Pascale M.

2013-09-01

Fully depleted silicon-on-insulator transistors coated with gadolinium oxide are shown to be effective thermal neutron dosimeters. The theoretical neutron detection efficiency is calculated to be higher for Gd{sub 2}O{sub 3} than for other practical converter materials. Proof-of-concept dosimeter devices were fabricated and tested during thermal neutron irradiation. The transistor current changes linearly with neutron dose, consistent with increasing positive charge in the SOI buried oxide layer generated by ionization from high energy {sup 157}Gd(n,γ){sup 158}Gd conversion electrons. The measured neutron sensitivity is approximately 1/6 the maximum theoretical value, possibly due to electron–hole recombination or conversion electron loss in interconnect wiring above the transistors. -- Highlights: • A novel Gd{sub 2}O{sub 3} coated FDSOI MOSFET thermal neutron dosimeter is presented. • Dosimeter can detect charges generated from {sup 157}Gd(n,γ){sup 158}Gd conversion electrons. • Measured neutron sensitivity is comparable to that calculated theoretically. • Dosimeter requires zero power during operation, enabling new application areas.

Nevada test site neutron dosimetry-problems/solutions

International Nuclear Information System (INIS)

Sygitowicz, L.S.; Bastian, C.T.; Wells, I.J.; Koch, P.N.

1991-01-01

Historically, neutron dosimetry at the NTS was done using NTA film and albedo LiF TLD's. In 1987 the dosimeter type was changed from the albedo TLD based system to a CR-39 track etch based system modeled after the program developed by D. Hankins at LLNL. Routine issue and return is performed quarterly for selected personnel using bar-code readers at permanent locations. The capability exists for work site issue as-needed. Issue data are transmitted by telephone to a central computer where it is stored until the dosimeter is returned, processed and read, and the dose calculation is performed. Dose equivalent calculations are performed using LOTUS 123 and the results are printed as a hard copy record. The issue and dose information are hand-entered into the Dosimetry database. An application is currently being developed to automate this sequence

A Dosimetry Study of Deuterium-Deuterium Neutron Generator-based In Vivo Neutron Activation Analysis.

Science.gov (United States)

Sowers, Daniel; Liu, Yingzi; Mostafaei, Farshad; Blake, Scott; Nie, Linda H

2015-12-01

A neutron irradiation cavity for in vivo neutron activation analysis (IVNAA) to detect manganese, aluminum, and other potentially toxic elements in human hand bone has been designed and its dosimetric specifications measured. The neutron source is a customized deuterium-deuterium neutron generator that produces neutrons at 2.45 MeV by the fusion reaction 2H(d, n)3He at a calculated flux of 7 × 10(8) ± 30% s(-1). A moderator/reflector/shielding [5 cm high density polyethylene (HDPE), 5.3 cm graphite and 5.7 cm borated (HDPE)] assembly has been designed and built to maximize the thermal neutron flux inside the hand irradiation cavity and to reduce the extremity dose and effective dose to the human subject. Lead sheets are used to attenuate bremsstrahlung x rays and activation gammas. A Monte Carlo simulation (MCNP6) was used to model the system and calculate extremity dose. The extremity dose was measured with neutron and photon sensitive film badges and Fuji electronic pocket dosimeters (EPD). The neutron ambient dose outside the shielding was measured by Fuji NSN3, and the photon dose was measured by a Bicron MicroREM scintillator. Neutron extremity dose was calculated to be 32.3 mSv using MCNP6 simulations given a 10-min IVNAA measurement of manganese. Measurements by EPD and film badge indicate hand dose to be 31.7 ± 0.8 mSv for neutrons and 4.2 ± 0.2 mSv for photons for 10 min; whole body effective dose was calculated conservatively to be 0.052 mSv. Experimental values closely match values obtained from MCNP6 simulations. These are acceptable doses to apply the technology for a manganese toxicity study in a human population.

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

Science.gov (United States)

Lee, Bongsoo; Kwon, Guwon; Shin, Sang Hun; Kim, Jaeseok; Yoo, Wook Jae; Ji, Young Hoon; Jang, Kyoung Won

2015-11-17

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

Spectra of fast neutrons using a lithiated glass film on silicon

International Nuclear Information System (INIS)

Wallace, Steven; Stephan, Andrew C.; Womble, Phillip C.; Begtrup, Gavi; Dai Sheng

2003-01-01

Experimental results of a neutron detector manufactured by coating a silicon charged particle detector with a film of lithiated glass are presented. The silicon surface barrier detector (SBD) responds to the 6 Li(n, alpha)triton reaction products generated in the thin film of lithiated glass entering the SBD. Neutron spectral information is present in the pulse height spectrum. An energy response is seen that clearly shows that neutrons from a Pu-Be source and from a deuterium-tritium (D-T) pulsed neutron generator can be differentiated and counted above a gamma background. The significant result is that the fissile content within a container can be measured using a pulsed D-T neutron generator using the neutrons that are counted in the interval between the pulses

Electrochemical development of particle tracks in CR-39 polymer dosimeter

International Nuclear Information System (INIS)

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

1985-09-01

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

Dosimetry methods in boron neutron capture therapy

Energy Technology Data Exchange (ETDEWEB)

Gambarini, G.; Artuso, E.; Felisi, M.; Regazzoni, V.; Giove, D. [Universita degli Studi di Milano, Department of Physics, Via Festa del Patrono 7, 20122 Milano (Italy); Agosteo, S.; Barcaglioni, L. [Istituto Nazionale di Fisica Nucleare, Milano (Italy); Campi, F.; Garlati, L. [Politecnico di Milano, Energy Department, Piazza Leonardo Da Vinci 32, 20133 Milano (Italy); De Errico, F. [Universita degli Studi di Pisa, Department of Civil and Industrial Engineering, Lungamo Pacinotti 43, 56126 Pisa (Italy); Borroni, M.; Carrara, M. [Fondazione IRCCS Istituto Nazionale Tumori, Medical Physics Unit, Via Venezian 1, 20133 Milano (Italy); Burian, J.; Klupak, V.; Viererbl, L.; Marek, M. [Research Centre Rez, Department of Neutron Physics, 250-68 Husinec-Rez (Czech Republic)

2014-08-15

Dosimetry studies have been carried out at thermal and epithermal columns of Lvr-15 research reactor for investigating the spatial distribution of gamma dose, fast neutron dose and thermal neutron fluence. Two different dosimetry methods, both based on solid state detectors, have been studied and applied and the accuracy and consistency of the results have been inspected. One method is based on Fricke gel dosimeters that are dilute water solutions and have good tissue equivalence for neutrons and also for all the secondary radiations produced by neutron interactions in tissue or water phantoms. Fricke gel dosimeters give the possibility of separating the various dose contributions, i.e. the gamma dose, the fast neutron dose and the dose due to charged particles generated during thermal neutron reactions by isotopes having high cross section, like 10-B. From this last dose, thermal neutron fluence can be obtained by means of the kerma factor. The second method is based on thermoluminescence dosimeters. In particular, the developed method draw advantage from the different heights of the peaks of the glow curve of such phosphors when irradiated with photons or with thermal neutrons. The results show that satisfactory results can be obtained with simple methods, in spite of the complexity of the subject. However, the more suitable dosimeters and principally their utilization and analysis modalities are different for the various neutron beams, mainly depending on the relative intensities of the three components of the neutron field, in particular are different for thermal and epithermal columns. (Author)

Dosimetry methods in boron neutron capture therapy

International Nuclear Information System (INIS)

Gambarini, G.; Artuso, E.; Felisi, M.; Regazzoni, V.; Giove, D.; Agosteo, S.; Barcaglioni, L.; Campi, F.; Garlati, L.; De Errico, F.; Borroni, M.; Carrara, M.; Burian, J.; Klupak, V.; Viererbl, L.; Marek, M.

2014-08-01

Dosimetry studies have been carried out at thermal and epithermal columns of Lvr-15 research reactor for investigating the spatial distribution of gamma dose, fast neutron dose and thermal neutron fluence. Two different dosimetry methods, both based on solid state detectors, have been studied and applied and the accuracy and consistency of the results have been inspected. One method is based on Fricke gel dosimeters that are dilute water solutions and have good tissue equivalence for neutrons and also for all the secondary radiations produced by neutron interactions in tissue or water phantoms. Fricke gel dosimeters give the possibility of separating the various dose contributions, i.e. the gamma dose, the fast neutron dose and the dose due to charged particles generated during thermal neutron reactions by isotopes having high cross section, like 10-B. From this last dose, thermal neutron fluence can be obtained by means of the kerma factor. The second method is based on thermoluminescence dosimeters. In particular, the developed method draw advantage from the different heights of the peaks of the glow curve of such phosphors when irradiated with photons or with thermal neutrons. The results show that satisfactory results can be obtained with simple methods, in spite of the complexity of the subject. However, the more suitable dosimeters and principally their utilization and analysis modalities are different for the various neutron beams, mainly depending on the relative intensities of the three components of the neutron field, in particular are different for thermal and epithermal columns. (Author)

Synthesis of high quality diamond film for the dosimeter realization in the radiotherapy domain

International Nuclear Information System (INIS)

Vaissiere, Nicolas

2014-01-01

This thesis aims to master the MPCVD synthesis of heteroepitaxial diamond films of high crystalline quality on iridium substrate for radiotherapy dosimeters. This objective has led us to develop the epitaxial iridium layer grown on SrTiO 3 substrates (001). A vacuum frame equipped with an electron gun has been developed and calibrated. The obtained layers characterized by XRD, possess a structural quality equivalent to the state of the art/in literature. Bias Enhanced Nucleation (BEN)- MPCVD induces nucleation of 'domains' on the iridium surface, according a unique nucleation pathway. Significant work has been conducted on (BEN)-MPCVD optimization to obtain a reliable and reproducible method for generating homogeneous 'domains' on a surface of 5 x 5 mm 2 . Combined characterizations (SEM, XPS, AES) of 'domains' surface enabled us to establish the identity card of their chemical and morphological properties. We demonstrate that they contain diamond nuclei. In addition, the temporal expansion of these 'domains' seems to follow preferential directions <110> of iridium lattice during the (BEN)-MPCVD stage. From these results, self-supported heteroepitaxial diamond films 100μ-m thick have been grown. The correlation between their crystalline quality and their detection response was conducted with the LCD dosimeter team. The inhomogeneities in the crystal structure due to structural defects have been identified. To study more locally these samples, a measurement campaign was carried out by microbeam X on the DIFFABS line at Soleil Synchrotron. The combination of the different knowledge acquired during this thesis has allowed the fabrication and characterization of the first detector based on heteroepitaxial diamond at the LCD laboratory. (author) [fr

Automated gamma spectrometry and data analysis on radiometric neutron dosimeters

International Nuclear Information System (INIS)

Matsumoto, W.Y.

1983-01-01

An automated gamma-ray spectrometry system was designed and implemented by the Westinghouse Hanford Company at the Hanford Engineering Development Laboratory (HEDL) to analyze radiometric neutron dosimeters. Unattended, automatic, 24 hour/day, 7 day/week operation with online data analysis and mainframe-computer compatible magnetic tape output are system features. The system was used to analyze most of the 4000-plus radiometric monitors (RM's) from extensive reactor characterization tests during startup and initial operation of th Fast Flux Test Facility (FFTF). The FFTF, operated by HEDL for the Department of Energy, incorporates a 400 MW(th) sodium-cooled fast reactor. Aumomated system hardware consists of a high purity germanium detector, a computerized multichannel analyzer data acquisition system (Nuclear Data, Inc. Model 6620) with two dual 2.5 Mbyte magnetic disk drives plus two 10.5 inch reel magnetic tape units for mass storage of programs/data and an automated Sample Changer-Positioner (ASC-P) run with a programmable controller. The ASC-P has a 200 sample capacity and 12 calibrated counting (analysis) positions ranging from 6 inches (15 cm) to more than 20 feet (6.1 m) from the detector. The system software was programmed in Fortran at HEDL, except for the Nuclear Data, Inc. Peak Search and Analysis Program and Disk Operating System (MIDAS+)

Plastic dosimeter

International Nuclear Information System (INIS)

Nagai, Shiro; Matsuda, Kohji.

1988-01-01

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

Evaluation of LLNL's Nuclear Accident Dosimeters at the CALIBAN Reactor September 2010

International Nuclear Information System (INIS)

Hickman, D.P.; Wysong, A.R.; Heinrichs, D.P.; Wong, C.T.; Merritt, M.J.; Topper, J.D.; Gressmann, F.A.; Madden, D.J.

2011-01-01

The Lawrence Livermore National Laboratory uses neutron activation elements in a Panasonic TLD holder as a personnel nuclear accident dosimeter (PNAD). The LLNL PNAD has periodically been tested using a Cf-252 neutron source, however until 2009, it was more than 25 years since the PNAD has been tested against a source of neutrons that arise from a reactor generated neutron spectrum that simulates a criticality. In October 2009, LLNL participated in an intercomparison of nuclear accident dosimeters at the CEA Valduc Silene reactor (Hickman, et.al. 2010). In September 2010, LLNL participated in a second intercomparison of nuclear accident dosimeters at CEA Valduc. The reactor generated neutron irradiations for the 2010 exercise were performed at the Caliban reactor. The Caliban results are described in this report. The procedure for measuring the nuclear accident dosimeters in the event of an accident has a solid foundation based on many experimental results and comparisons. The entire process, from receiving the activated NADs to collecting and storing them after counting was executed successfully in a field based operation. Under normal conditions at LLNL, detectors are ready and available 24/7 to perform the necessary measurement of nuclear accident components. Likewise LLNL maintains processing laboratories that are separated from the areas where measurements occur, but contained within the same facility for easy movement from processing area to measurement area. In the event of a loss of LLNL permanent facilities, the Caliban and previous Silene exercises have demonstrated that LLNL can establish field operations that will very good nuclear accident dosimetry results. There are still several aspects of LLNL's nuclear accident dosimetry program that have not been tested or confirmed. For instance, LLNL's method for using of biological samples (blood and hair) has not been verified since the method was first developed in the 1980's. Because LLNL and the other DOE

EVIDOS: Individual dosimetry in mixed neutron and photon radiation fields

International Nuclear Information System (INIS)

Vanhavere, F.

2006-01-01

The EVIDOS project (partly funded by the European Commission RTD Programme: Nuclear Energy, Euratom Framework Programme V, 1998-2002, Contract No FIKR-CT-2001-00175) aimed at improving individual monitoring in mixed neutron-photon radiation fields by evaluating the performance of routine and novel personal dosimeters for mixed radiation, and by giving guidelines for deriving sufficiently accurate values of personal dose equivalent from the readings of area survey instruments and dosimeters. The main objective of EVIDOS was to evaluate different methods for individual dosimetry in mixed neutron-photon work-places in nuclear industry. This implied a determination of the capabilities and limitations of personal dosimeters and the establishment of methods to enable sufficiently accurate values of personal dose equivalent from spectrometers, area survey instruments and routine personal dosimeters. Also novel electronic personal dosimeters were investigated. To this end spectrometric and dosimetric investigations in selected representative workplaces in nuclear industry where workers can receive significant neutron doses were performed. As part of this project, a number of tasks were executed, in particular: (1) the determination of the energy and direction distribution of the neutron fluence; (2) the derivation of the (conventionally true) values of radiation protection quantities; (3) the determination of the readings of routine and innovative personal dosimeters and of area monitors; and (4) the comparison between dosimeter readings and values of the radiation protection quantities

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-07-01

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

Method to improve the evaluation of a combination track-etch dosimeter/spectrometer

International Nuclear Information System (INIS)

Brackenbush, L.W.; Parkhurst, M.A.; Hadlock, D.E.; Faust, L.G.

1983-09-01

A paper is summarized which describes a method of determining the neutron energy spectrum through spectrum unfolding techniques to more accurately assess the dose equivalent from track-etch dosimeters. A mathematical technique is described which can be used in conjunction with the neutron detectors to more accurately estimate neutron dose equivalent. The technique is based upon solutions to a system of Fredholm integral equations of the first type

Personal dosimetry in a mixed field of high energy muons and neutrons

International Nuclear Information System (INIS)

Cossairt, J.D.; Elwyn, A.J.

1986-11-01

High energy accelerators quite often emit muons. These particles behave in matter as would heavy electrons and are thus difficult to attenuate with shielding in many situations. Hence, these muons can be a source of radiation exposure to personnel and suitable methods of measuring the absorbed dose received to these people is obviously required. In practical situations, such muon radiation fields are often mixed with neutrons, well-known to be an even more troublesome particle species with respect to dosimetry. In this paper, we report on fluence measurements made in such a mixed radiation field and a comparison of dosimeter responses. We conclude that commercial self-reading dosimeters and film badges provided an adequate measure of the absorbed dose due to muons

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.

Neutron/gamma dose separation by the multiple-ion-chamber technique

International Nuclear Information System (INIS)

Goetsch, S.J.

1983-01-01

Many mixed n/γ dosimetry systems rely on two dosimeters, one composed of a tissue-equivalent material and the other made from a non-hydrogenous material. The paired chamber technique works well in fields of neutron radiation nearly identical in spectral composition to that in which the dosimeters were calibrated. However, this technique is drastically compromised in phantom due to the degradation of the neutron spectrum. The three-dosimeter technique allows for the fall-off in neutron sensitivity of the two non-hydrogenous dosimeters. Precise and physically meaningful results were obtained with this technique with a D-T source in air and in phantom and with simultaneous D-T neutron and 60 Co gamma ray irradiation in air. The MORSE-CG coupled n/γ three-dimensional Monte Carlo code was employed to calculate neutron and gamma doses in a water phantom. Gamma doses calculated in phantom with this code were generally lower than corresponding ion chamber measurements. This can be explained by the departure of irradiation conditions from ideal narrow-beam geometry. 97 references

Neutron methods for the direct determination of the magnetic induction in thick films

Energy Technology Data Exchange (ETDEWEB)

Kozhevnikov, S.V., E-mail: kozhevn@nf.jinr.ru [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Ott, F. [CEA, IRAMIS, Laboratoire Léon Brillouin, F-91191 Gif sur Yvette (France); CNRS, IRAMIS, Laboratoire Léon Brillouin, F-91191 Gif sur Yvette (France); Radu, F. [Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein Strasse 15, D-12489 Berlin (Germany)

2016-03-15

We review different neutron methods which allow extracting directly the value of the magnetic induction in thick films: Larmor precession, Zeeman spatial beam-splitting and neutron spin resonance. Resulting parameters obtained by the neutron methods and standard magnetometry technique are presented and compared. The possibilities and specificities of the neutron methods are discussed. - Highlights: • We present neutron methods for investigations of the thick magnetic films. • It is the methods for the direct determination of the magnetic induction. • Magnetic induction in bulk, at single interface and in a single domain. • It is Larmor precession, Zeeman spatial beam-splitting and neutron spin resonance. • These methods are complementary to polarized neutron reflectometry.

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.

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

International Nuclear Information System (INIS)

Chen, Felipe; Graeff, Carlos F.O.; Baffa, Oswaldo

2005-01-01

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

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

International Nuclear Information System (INIS)

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

1996-01-01

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

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

Neutron measuring instruments for radiation protection

International Nuclear Information System (INIS)

Heinzelmann, M.; Schneider, W.; Hoefert, M.; Kuehn, H.; Jahr, R.; Wagner, S.; Piesch, E.

1979-09-01

The present report deals with selected topics from the field of neutron dosimetry for radiation protection connected with the work of the subcommittee 6802 in the Standards Committee on Radiology (NAR) of the German Standards Institute (DIN). It is a sort of material collection. The topics are: 1. Measurement of the absorbed-energy dose by a) ionization chambers in fields of mixed radiation and b) recoil-proton proportional counting tubes. 2. Measurement of the equivalent dose, neutron monitors, combination methods by a) rem-meters, b) recoil-proton counting tubes, c) recombination method, tissue-equivalent proportional counters, activation methods for high energies in fields of mixed radiation, d) personnel dosimetry by means of ionization chambers and counting tubes, e) dosimetry by means of activation methods, nuclear track films, nonphotographic nuclear track detectors and solid-state dosimeters. (orig./HP) [de

Estimation of low-level neutron dose-equivalent rate by using extrapolation method for a curie level Am–Be neutron source

International Nuclear Information System (INIS)

Li, Gang; Xu, Jiayun; Zhang, Jie

2015-01-01

Neutron radiation protection is an important research area because of the strong radiation biological effect of neutron field. The radiation dose of neutron is closely related to the neutron energy, and the connected relationship is a complex function of energy. For the low-level neutron radiation field (e.g. the Am–Be source), the commonly used commercial neutron dosimeter cannot always reflect the low-level dose rate, which is restricted by its own sensitivity limit and measuring range. In this paper, the intensity distribution of neutron field caused by a curie level Am–Be neutron source was investigated by measuring the count rates obtained through a 3 He proportional counter at different locations around the source. The results indicate that the count rates outside of the source room are negligible compared with the count rates measured in the source room. In the source room, 3 He proportional counter and neutron dosimeter were used to measure the count rates and dose rates respectively at different distances to the source. The results indicate that both the count rates and dose rates decrease exponentially with the increasing distance, and the dose rates measured by a commercial dosimeter are in good agreement with the results calculated by the Geant4 simulation within the inherent errors recommended by ICRP and IEC. Further studies presented in this paper indicate that the low-level neutron dose equivalent rates in the source room increase exponentially with the increasing low-energy neutron count rates when the source is lifted from the shield with different radiation intensities. Based on this relationship as well as the count rates measured at larger distance to the source, the dose rates can be calculated approximately by the extrapolation method. This principle can be used to estimate the low level neutron dose values in the source room which cannot be measured directly by a commercial dosimeter. - Highlights: • The scope of the affected area for

Measurement of epithermal neutrons by a coherent demodulation technique

CERN Document Server

Horiuchi, N; Takahashi, H; Kobayashi, H; Harasawa, S

2000-01-01

Epithermal neutrons have been measured using a neutron dosimeter via a coherent demodulation technique. This dosimeter consists of CsI(Tl)-photodiode scintillation detectors, four of which are coupled to neutron-gamma converting foils of various sizes. Neutron-gamma converting foils of In, Au and Co materials were used, each of which has a large capture cross section which peaks in the epithermal neutron energy region. The type of foil was selected according to the material properties that best correspond to the energy of the epithermal neutrons to be measured. In addition, the proposed technique was applied using Au-foils in order to measure the Cd ratio. The validity of the proposed technique was examined using an sup 2 sup 4 sup 1 Am-Be source placed in a testing stack of polyethylene blocks, and the results were compared with the theoretical values calculated by the Monte Carlo calculation. Finally, the dosimeter was applied for measuring epithermal neutrons and the Cd ratio in an experimental beam-tube o...

A new polarized neutrons method for studying depth-inhomogeneously magnetized magnetic films

International Nuclear Information System (INIS)

Korneev, D.A.

1990-01-01

The main specific features of the process of polarized thermal neutrons specular reflection from the surface of depth-inhomogeneously magnetic films are considered theoretically. It is shown how using the method of specular reflection of polarized thermal neutrons from such a films surface, one may restore the depth distribution of the local magnetization vector M-vector(z). 9 refs

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

International Nuclear Information System (INIS)

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

2008-01-01

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

Test of the fast thin-film ferromagnetic shutters for ultracold neutrons

International Nuclear Information System (INIS)

Pokotilovskij, Yu.N.; Novopol'tsev, M.I.; Geltenbort, P.

2008-01-01

Test of thin-film ferromagnetic shutters of two types for ultracold neutrons has been performed. The first type is based on neutron reflection from the sequence of successively placed thin ferromagnetic layers with oppositely directed magnetization. The second one is based on neutron refraction in ferromagnetic foils inserted in the beam

Measurement of neutron dose and spectra at light-water reactors

International Nuclear Information System (INIS)

Soldat, K.L.; Endres, G.W.R.; Cummings, F.M.

1982-08-01

In choosing one dosimeter over another, both sensitivity and precision must be addressed. It has been determined that dosimeters employing NTA film lack adequate sensitivity for use inside containment of nuclear plants. From this study, it is apparent that CR-39 and polycarbonate track etch films used without radiators are also inadequate. The rest of the dosimeters tested displayed adequate sensitivity. The two general types of dosimeters which comprise that group are: (1) TLDs and (2) the polycarbonate track etch which was used in conjunction with (n, α) radiators. The precision of the TLD dosimeter depends on the calibration technique and response correction technique. TLD dosimeters calibrated to D 2 O-moderated californium-252 or corrected based on 9- to 3-in. sphere response rates seemed to function best inside reactor containment. Polycarbonate track etch film with (n, α) radiators was found to be sensitive enough for use inside reactor containment; however, the standard deviation for the results was roughly twice the value of the most precise TLD albedo dosimeters. Also, several of the polycarbonate dosimeters saturated, rendering any evaluation impossible

Conversion from film to image plates for transfer method neutron radiography of nuclear fuel

Energy Technology Data Exchange (ETDEWEB)

Craft, Aaron E.; Papaioannou, Glen C.; Chichester, David L.; Williams, Walter J.

2017-02-01

This paper summarizes efforts to characterize and qualify a computed radiography (CR) system for neutron radiography of irradiated nuclear fuel at Idaho National Laboratory (INL). INL has multiple programs that are actively developing, testing, and evaluating new nuclear fuels. Irradiated fuel experiments are subjected to a number of sequential post-irradiation examination techniques that provide insight into the overall behavior and performance of the fuel. One of the first and most important of these exams is neutron radiography, which provides more comprehensive information about the internal condition of irradiated nuclear fuel than any other non-destructive technique to date. Results from neutron radiography are often the driver for subsequent examinations of the PIE program. Features of interest that can be evaluated using neutron radiography include irradiation-induced swelling, isotopic and fuel-fragment redistribution, plate deformations, and fuel fracturing. The NRAD currently uses the foil-film transfer technique with film for imaging fuel. INL is pursuing multiple efforts to advance its neutron imaging capabilities for evaluating irradiated fuel and other applications, including conversion from film to CR image plates. Neutron CR is the current state-of-the-art for neutron imaging of highly-radioactive objects. Initial neutron radiographs of various types of nuclear fuel indicate that radiographs can be obtained of comparable image quality currently obtained using film. This paper provides neutron radiographs of representative irradiated fuel pins along with neutron radiographs of standards that informed the qualification of the neutron CR system for routine use. Additionally, this paper includes evaluations of some of the CR scanner parameters and their effects on image quality.

Increase of the electrical resistance of thin aluminium film due to 14 MeV neutron irradiation

Energy Technology Data Exchange (ETDEWEB)

Agrawal, S K; Kumar, U; Singh, S P; Bhattacharya, S; Nigam, A K [Banaras Hindu Univ. (India). Dept. of Physics

1978-01-01

The effect of 14 MeV neutron bombardment on the electrical resistance of 500 A thick vacuum-coated Al film is investigated. In the beginning, a slow, then sharp and finally again slow increase is observed in the electrical resistance of the film. Transmission electron micrographs of the film after the same dose of neutron irradiation show a large number of defects produced in the film due to neutron irradiation, which seems to be the cause of this increase.

Study of the Radiochromic Film for High Dose Measurement in Radiation Processing

Directory of Open Access Journals (Sweden)

CHEN Yi-zhen

2016-02-01

Full Text Available To establish the radiochromic film dosimeter for high dose level measurement during radiation processing, By corresponding formula and its preparation process research, batches of radiochromic film dosimeters were prepared using nylon as substrate and pararosaniline cyanide as dye. In Co-60 gamma reference radiation field, dosimetry response performance of radiochromic film was studied and results showed that the repeatability was good to 1.0%. The response curves demonstrated good linearity in the dose range of 5-210 kGy, and the signal of radiochromic film dosimeters after irradiation under the condition of low temperature storage within 2 weeks was stable. In addition, the radiochromic film dosimeters were not found to have noticeable dose rate dependence in the range of this experiment. In the linear dose range, radiochromic film dosimeter measures the absorbed dose, with extended uncertainty 4.2% (k=2 for Co-60 gamma rays. The film was suitable as dosimeters for the parameters measurement of the electron beam on the accelerator.

Evaluation of the neutron dose received by personnel at the LLNL

International Nuclear Information System (INIS)

Hankins, D.E.

1982-01-01

This report was prepared to document the techniques being used to evaluate the neutron exposures received by personnel at the LLNL. Two types of evaluations are discussed covering the use of the routine personnel dosimeter and of the albedo neutron dosimeter. Included in the report are field survey results which were used to determine the calibration factors being applied to the dosimeter readings. Calibration procedures are discussed and recommendations are made on calibration and evaluation procedures

Personnel neutron dosimetry using TLD elements at PNC

International Nuclear Information System (INIS)

Ishiguro, Hideharu

1985-01-01

The evaluation method of neutron dose equivalent was studied on the basis of the albedo type neutron dosimetory to design the personnel dosimeter. The dosimeter was composed of three 6 Li 2 10 B 4 O 7 (Cu) TL elements and one 7 Li 2 11 B 4 O 7 (Cu) element. The equations for assessing thermal, epithermal and fast neutron dose equivalents were derived by 252 Cf, 241 Am-Be and PuO 2 neutron sources. The minimum detectable amount of 6 Li 2 10 B 4 O 7 (Cu) element to thermal neutron was 0.02 m rem. The neutron dose equivalent and the gamma one were evaluated separately within about 20 % error in the mixed radiation field. (author)

Thin layer alanine dosimeter with optical spectrophotometric evaluation

International Nuclear Information System (INIS)

Zagorski, Z.P.

2000-01-01

Experience in the high dose dosimetry of gamma radiation, gathered in our group from the sixties till now, allows to express the opinion, that techniques applied are adequate to solve problems. It can be confirmed by the fact that 60% of laboratories participating in the international comparison during the duration of the contract obtained satisfactory results. Adaptation of these methods, in particular of the alanine-ESR dosimetry to highly inhomogeneous fields of EB gives poor results, as it has been shown on thin films of the alanine/polymer composite. However, the applications of these films give excellent results if the concentration of the radical CH 3 C·H CO 2 - is measured by diffuse reflection spectrophotometry, which tolerates poor transparency of the composite and is insensitive to the orientation of crystals of alanine in thin films, what is disqualifying the ESR measurements. The development of thin-film dosimeters for EB processing was possible due to new developments in solid state radiation chemistry. The research has revealed some unsolved questions, e.g. of the high temperature coefficient of alanine based dosimeters, of the role of the size of spurs and the necessity to adapt dosimetry to the energy spectrum of electrons, because every type of accelerators differs in that respect. (author)

Pen dosimeters

CERN Multimedia

SC/RP Group

2006-01-01

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

Investigation of the effect of some irradiation parameters on the response of various types of dosimeters to electron irradiation

International Nuclear Information System (INIS)

Farah, K.; Kuntz, F.; Kadri, O.; Ghedira, L.

2004-01-01

Several undyed and dyed polymer films are commercially available for dosimetry in intense radiation fields, especially for radiation processing of food and sterilisation of medical devices. The effects of temperature during irradiation and post-irradiation stability, on the response of these dosimeters are of importance to operators of irradiation facilities. The present study investigates the effects of temperature during irradiation by 2.2 MeV electrons beam accelerator and post irradiation storage on the response of several types of dosimeter films. All dosimeters showed a significant effect of temperature during irradiation and post-irradiation storage

Investigation of the effect of some irradiation parameters on the response of various types of dosimeters to electron irradiation

Energy Technology Data Exchange (ETDEWEB)

Farah, K. E-mail: k.farah@cnstn.rnrt.tn; Kuntz, F.; Kadri, O.; Ghedira, L

2004-10-01

Several undyed and dyed polymer films are commercially available for dosimetry in intense radiation fields, especially for radiation processing of food and sterilisation of medical devices. The effects of temperature during irradiation and post-irradiation stability, on the response of these dosimeters are of importance to operators of irradiation facilities. The present study investigates the effects of temperature during irradiation by 2.2 MeV electrons beam accelerator and post irradiation storage on the response of several types of dosimeter films. All dosimeters showed a significant effect of temperature during irradiation and post-irradiation storage.

Preparation of alanine/ESR dosimeter using different binder of polymer blend

International Nuclear Information System (INIS)

Razzak, M.T.; Sudiro, Sutjipto; Sudradjat, Adjat; Waskito, Ashar; Djamili, M.F.

1995-01-01

Different composition of polymer blend of low density polyethylene (PE) and polystyrene (PS) have been studied to be used as a binder for the preparation of Alanine/ESR dosimeter. The polymer binder and Alanine powder were blended in Laboplastomil Mixer at 140 o C and then it was pressed into a plastic film of 0.50 mm thickness. The film was cut into sample size of 250 mm x 2.5 mm and irradiated by gamma rays from a cobalt-60 source at different dose and dose rate. It was found that a blend of Alanine, PS and PE in composition of 60:30:10 is appropriate to prepare the Alanine/ESR dosimeter. (author)

Studies on the radiation-induced coloration mechanism of the cellulose triacetate film dosimeter

International Nuclear Information System (INIS)

Matsuda, Koji; Nagai, Siro

1991-01-01

The species responsible for the coloration of the cellulose triacetate (CTA) film dosemeter have been studied using ultraviolet, electron spin resonance, infrared and gas chromatographic techniques. The post-irradiation change in the optical density at 280 nm indicates that the coloration occurs not only during irradiation (in situ coloration) but also after irradiation (post-irradiation coloration) and that in situ coloration is due to unstable and stable components. The species responsible for the unstable component of in situ coloration are ascribed to the radicals produced from CTA molecules and those for the stable component to the radiolysis products from CTA and triphenyl phosphate contained in the dosimeter. On the other hand, post-irradiation coloration is attributed to the formation of carbonyl groups in CTA molecules, which is induced by reaction with NO 2 produced by irradiation of air. (author)

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

Science.gov (United States)

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

2018-06-01

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

Thermogravimetric analysis of reactor-neutrons-irradiated LEXAN polycarbonate film

International Nuclear Information System (INIS)

Kalsi, P.C.

2000-01-01

The effects of reactor-neutrons irradiation on the thermogravimetric (TG) analysis of LEXAN polycarbonate film in air were studied. Irradiation enhances the degradation rate and the effect increases further with increasing neutron fluence. The kinetics of the different steps of degradation were also evaluated from the TG curves. The activation energy values calculated for all the degradation stages decrease on irradiation. (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

Polarized Neutron Reflectivity Simulation of Ferromagnet/ Antiferromagnet Thin Films

Energy Technology Data Exchange (ETDEWEB)

Kim, Ki Yeon; Lee, Jeong Soo

2008-02-15

This report investigates the current simulating and fitting programs capable of calculating the polarized neutron reflectivity of the exchange-biased ferromagnet/antiferromagnet magnetic thin films. The adequate programs are selected depending on whether nonspin flip and spin flip reflectivities of magnetic thin films and good user interface are available or not. The exchange-biased systems such as Fe/Cr, Co/CoO, CoFe/IrMn/Py thin films have been simulated successfully with selected programs.

Radiation dosimetry by neutron or X ray fluorescence activation of residual silver in ionographic emulsions

International Nuclear Information System (INIS)

Heilmann, C.

1987-01-01

A global measuring technique which is sensitive enough to detect small silver contents in films for dosimetry applications is presented. The applications studied are neutron dosimetry by measuring residual silver due to recoil protons in developed emulsions and high dose dosimetry by the detection of photolytic silver in fixed emulsions. An individual fast neutron dosimeter which can be used in radiation protection was developed, along with an automatic data analysis and readout system. Application of this technique to the measurement of high radiation doses (100 to 1 million Gy) via the measurement of photolytic silver in fixed, but undeveloped, emulsions confirms the usefulness of the method [fr

Evaluation of a thermoluminescent dosimeter for personnel monitoring in the nuclear-radiation environment

International Nuclear Information System (INIS)

Johnson, F.A.; McGowan, S.; Gravelle, R.A.

1983-09-01

Efforts to improve the responses of phosphor/polyethylene TLDs to neutrons in the 1-MeV range have been only partially successful. Some increases in response have resulted from reduction of phosphor grain size and substitution of CaSO 4 :Tm with CaF 2 :Mn or CaF 2 :Dy. Reasons for the continuing low response are not fully understood. Calculated responses of the TLDs, when located on the body, show a closer correlatin with the dose received by the bone marrow as a result of exposure to a weapon spectrum than is evident for the case of flat-response dosimeters. However the TLDs exhibit a greater difference in their response to a weapon spectrum as compared with that to a pure gamma spectrum than is the case for a flat-response dosimeter. The disparity becomes even larger when the dose measured by the dosimeters is expressed in terms of the biologically effective dose absorbed in the bone marrow. Investigation of the ability of a dosimeter, which is sensitive only to γ-rays, to provide a measure of the total bone marrow dose produced by a combined flux of γ-rays and neutrons, indicates that there is an unacceptable difference between the response to a pure gamma spectrum and that to a mixed spectrum from a weapon

Sensitive color dosimeters using photochromic diarylethenes

International Nuclear Information System (INIS)

Irie, Setsuko; Irie, Masahiro

2008-01-01

Various types of color dosimeters are conveniently used for estimating absorbed dose in the radiation sterilization of biomedical materials. Diarylethenes with heterocyclic aryl groups are extensively studied for the applications to the optoelectronic devices, such as optical memory media and photowitching devices because of their thermally irreversible and fatigue-resistant properties. The colors of diarylethenes never fade in the dark conditions. The thermally stable dithienylethene derivatives are applied to sensitive color dosimeters. Upon γ-irradiation, polystyrene films containing diarylethene derivatives, such as 1,2-bis(2-methyl-5-phenyl-3-thienyl) perfluorocyclopentene 1 or 1,2-bis(2,5-dimethyl-3-thienyl) perfluorocyclopentene 2, and fluorescent metal complexes turned blue or red. Even if the absorbed dose was as small as 10 Gy, a clear color change was observed. (author)

Neutron dosimetry program at Mound - problems and solutions

International Nuclear Information System (INIS)

Winegardner, M.K.

1991-01-01

The Mound personnel neutron dosimetry program utilizes TLD albedo technology. The neutron dosimeter design incorporates a two-element spectrometer for site-specific neutron quality determination and empirical application of field neutron calibration factors. Design elements feature two Li(6)F (TLD- 600) chips for neutron detection and one Li(7)F (TLD-700) chip for gamma compensation of the TLD- 600 chips. One TLD-600 chip is Cadmium shielded on the front side of the dosimeter, the other is Cadmium shielded from the back side. Tin filters are placed opposite of the Cadmium shield on each of the TLD-600 chips and on both sides of the TLD-700 chip for symmetrically equivalent gamma absorption characteristics. Neutron quality determination is accomplished by the albedo neutron-to- incident thermal neutron response ratio above the Cadmium cutoff. This front Cadmium shielded-to-back Cadmium shielded response ratio, compensated for the presence of gamma radiation, provides the basis for neutron energy calibration via the albedo response curve

Composite material dosimeters

Science.gov (United States)

Miller, Steven D.

1996-01-01

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

Investigation on feasibility and detection limits for determination of coating film thickness by neutron activation analysis

International Nuclear Information System (INIS)

Yao Maoying; Xu Jiayun; Zhang Dida; Yang Zunyong; Yao Zhenqiang; Wang Mingqiu; Gao Dangzhong

2010-01-01

A method for the determination of coating film thickness by neutron activation was proposed in this paper. After Au, Al and Cu et al.films were activated with a Am-Be neutron source, the characteristic γ-rays emitted by the activated nuclides in the films were counted with a HPGe γ spectrometer. The detection limits of film thickness by using a nuclear reactor neutron source were deduced on the basis of the γ-ray counts and the Monte-Carlo simulated detection efficiencies. The possible detection limits are typically 4-5 orders of magnitude better than those by fluorescent X-ray method, which is currently widely used to determine coating film thickness. (authors)

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

Sunna 535-nm photo-fluorescent film dosimeter response to different environmental conditions

International Nuclear Information System (INIS)

Murphy, M.K.; Kovacs, A.; McLaughlin, W.L.; Miller, S.D.; Puhl, J.M.

2003-01-01

Evaluations on the influence of environmental variabilities on the red fluorescence component of the Sunna Model γ photo-fluorescent dosimeter TM have previously been reported. This present paper describes the environmental effects on the response of the green fluorescence component of the same dosimeter, which is manufactured using the injection molding technique. The results presented include temperature, relative humidity, and light influences both during and after irradiation. The green fluorescence signal shows a significant dependence on irradiation temperature below room temperature at 1%/ deg. C. Above room temperature (approximately 24-60 deg. C), the irradiation temperature effect varies from -0.1%/ deg. C to 1.0%/ deg. C, depending on the absorbed dose level. For facilities with irradiation temperatures between 30 deg. C and 60 deg. C and absorbed dose levels above 10 kGy, irradiation temperature effects are minimal. Light-effects results indicate that the dosimeter is influenced by ultraviolet and blue wavelengths during irradiation as well as during the post-irradiation stabilization period (approximately 22 h), requiring the use of light-tight packaging. Results also show that the dosimeter exhibits negligible effects from ambient moisture during and after irradiation when in the range of 33-95% relative humidity

Human hair as a pollutant dosimeter

International Nuclear Information System (INIS)

Al-Hashimi, A.

1991-01-01

Human hair has been proved to be a better dosimeter than even blood for tracing most of the heavy metal toxins when they penetrate the biosphere. The high precision of the neutron activation analysis (NAA) enabled researchers to elegantly differentiate between endogenous and exogenous contamination and thoroughly study poisonings caused by these physiologically-unimportant elements. Extensive volume of bench-scale work has been accomplished in these laboratories to show the capacity of INAA to detect the presence of 10 nuclides (or more) with a precision of about 5%. The principal objective of the present study is to employ this assaying power and the tendency of scalp hair to uptake heavy metals from aqueous solutions, to design a dosimeter which can easily be used by the environmentalists. The findings should also be of interest to the waste-management people who are searching for a cost-effective technique to remove these pollutants from relatively large volumes of industrial effluents

Dosimeter charging apparatus

International Nuclear Information System (INIS)

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

1985-01-01

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

Evaluation of gamma and neutron irradiation effects on the properties of mica film capacitors

International Nuclear Information System (INIS)

Roy, Rajesh; Pandya, Arun

2005-01-01

We present an investigation of gamma and neutron radiation effects on mica film capacitors from an electrical point of view. We have studied quantitatively the effects of gamma and neutron irradiation on mica film capacitors of thickness, 20 and 40 μm (0.7874 and 1.5748 mil) with two different areas, 01 and 04 cm 2 . The capacitance has been measured at room temperature in the frequency range 100 Hz-10 MHz. Negligible change in the capacitance due to high gamma dose of 60 Co, 15 kGy at dose rate 0.25 kGy/h, has been observed. However, appreciable change in the capacitance has been observed due to low doses of fast neutrons (cumulative dose, 115 cGy) with flux ∼ 9.925 X 10 7 neutrons/cm 2 h from 252 Cf neutron source of fluence, 2.5 x 10 7 neutrons/s. We have also observed that the impact of gamma and neutron irradiation is more at frequencies higher than 10 kHz, These results show that the mica capacitors do not show any radiation response below 10 kHz. The study shows the radiation response of mica film capacitors to gamma and fast neutron radiations. Mica capacitors show low gamma radiation response in comparison to fast neutron radiation, because a total dose of kGy order has been given by gamma source and only few cGy dose has been given by fast neutron source. (author)

Characterization of film-converter screens systems for neutron radiography; Caracterizacao de sistemas filme-conversor para radiografia com neutrons

Energy Technology Data Exchange (ETDEWEB)

Andrade, Marcos Leandro Garcia

2002-07-01

In general a good quality radiography is that one able to furnish high contrast and sharp edge images. Technically 'high contrast' means high capability to discern material thickness and 'sharp edges', high resolution power. In the present work the optimal conditions to obtain neutron radiography images by using the following film-converter screen systems, Kodak-AA/Gd vaporated; Kodak-AA/Gd metallic; Kodak-AA/LiF; Min-R/GdS{sub 2}O{sub 4}, have been determined. The irradiations were performed in a radiographic facility which was designed and constructed by the neutron radiography working group and is installed at the beamhole 08 of the IEA-R1 nuclear research reactor of the IPEN-CNEN/SP. In order to determine such conditions, the start point was to evaluate the neutron exposure interval for which the optical contrast is maximal and so quantify the sensitivity or capability to discern material thickness, as well as the spatial resolution achieved in the radiographic image, for these systems. The best results have been obtained for the Kodak-AA/Gd vaporated system which is able to discern, for example, 0,024 cm of lucite, with a maximal resolution of 22{mu}m. The radiography images presently obtained in IPEN-CNEN/SP have similar quality when compared to the ones from several other research centers, around the world, whose making use of the same film-converter screens systems. (author)

Thin film tritium dosimetry

Science.gov (United States)

Moran, Paul R.

1976-01-01

The present invention provides a method for tritium dosimetry. A dosimeter comprising a thin film of a material having relatively sensitive RITAC-RITAP dosimetry properties is exposed to radiation from tritium, and after the dosimeter has been removed from the source of the radiation, the low energy electron dose deposited in the thin film is determined by radiation-induced, thermally-activated polarization dosimetry techniques.

Neutron irradiation of sputtered NbN films

International Nuclear Information System (INIS)

Weber, H.W.; Gregshammer, P.; Gray, K.E.; Kampwirth, R.T.

1989-01-01

In addition to the excellent high-field superconducting properties of NbN, it is the strain and radiation tolerance, measured in bulk NbN, which makes the material so attractive for large high-field magnets, especially for fusion applications. The authors report neutron irradiation experiments on sputtered NbN films, up to a fluence of 10/sup 23/ m/sup -2/ (E > 0.1 MeV), which prove that NbN films are also extremely radiation-hard high-field superconductors. Both the transition temperatures, T/sub c/, and the normal state resistivities show only small changes with neutron fluence. Concerning the critical current densities, j/sub c/, degradations by as much as 30% are observed at low fields, whereas in an intermediate field range (11-15 T) virtually no change of j/sub c/ and at high fields near 20 T even an increase of j/sub c/ are found. The latter observation is ascribed to a radiation-induced increase of the upper critical field, B/sub c2/, and to the occurence of peak effects near B/sub c2/

Neutron accident dosimeter based on SSNTDs

International Nuclear Information System (INIS)

Palfalvi, J.; Sajo-Bohus, L.

1998-01-01

A sandwich type track etch detector of CR-39 was developed utilizing neutron-proton recoil and (n,α) reactions. Applying gold and Cd filters this system turns into a threshold detector and also it combines the albedo and the direct detection methods; thus it becomes possible to detect neutrons in three or more energy ranges depending on the number of gold degraders of different thickness allowing dose assessment with an uncertainty of about 20%, as blank tests have proved when a single gold foil of 20 μm thick was used. (author)

Improving neutron dosimetry using bubble detector technology

International Nuclear Information System (INIS)

Buckner, M.A.

1993-02-01

Providing accurate neutron dosimetry for a variety of neutron energy spectra is a formidable task for any dosimetry system. Unless something is known about the neutron spectrum prior to processing the dosimeter, the calculated dose may vary greatly from that actually encountered; that is until now. The entrance of bubble detector technology into the field of neutron dosimetry has eliminated the necessity of having an a priori knowledge of the neutron energy spectra. Recently, a new approach in measuring personnel neutron dose equivalent was developed at Oak Ridge National Laboratory. By using bubble detectors in combination with current thermoluminescent dosimeters (TLDs) as a Combination Personnel Neutron Dosimeter (CPND), not only is it possible to provide accurate dose equivalent results, but a simple four-interval neutron energy spectrum is obtained as well. The components of the CPND are a Harshaw albedo TLD and two bubble detectors with theoretical energy thresholds of 100 key and 1500 keV. Presented are (1) a synoptic history surrounding emergence of bubble detector technology, (2) a brief overview of the current theory on mechanisms of interaction, (3) the data and analysis process involved in refining the response functions, (4) performance evaluation of the original CPND and a reevaluation of the same data under the modified method, (5) the procedure used to determine the reference values of component fluence and dose equivalent for field assessment, (6) analysis of the after-modification results, (7) a critique of some currently held assumptions, offering some alternative explanations, and (8) thoughts concerning potential applications and directions for future research

CFRMF spectrum update and application to dosimeter cross-section data testing

International Nuclear Information System (INIS)

Anderl, R.A.; Harker, Y.D.; Millsap, D.A.; Rogers, J.W.; Ryskamp, J.M.

1982-01-01

The Coupled Fast Reactivity Measurements Facility (CFRMF) at the Idaho National Engineering Laboratory (INEL) is a Cross Section Evaluation Working Group (CSEWG) benchmark for data testing of dosimetry, fission-product and actinide cross sections important to fast-reactor technology. In this paper we present the results of our work in updating the CFRMF spectrum characterization and in applying CFRMF integral data to testing ENDF/B-V dosimeter cross sections. Updated characterization of the central neutron spectrum includes the results of neutronics calculations with ENDF/B-V nuclear data, the generation of a fine-group spectrum representation for integral data-testing applications, and a sensitivity and uncertainty analysis which provides a flux-spectrum covariance matrix related to uncertainties and correlations in the nuclear data used in a neutronics calculation. Our application of CFRMF integral data to cross section testing has included both conventional integral testing analyses and least-squares-adjustment analyses with the FERRET code. The conventional integral data-testing analysis, based on C/E ratios, indicates discrepancies outside the estimated integral test uncertainty for the 6 Li(n,He), 10 B(n,He), 47 Ti(n,p), 58 Fe(n,γ), 197 Au(n,γ) and 232 Th(n,γ) cross sections. The integral test uncertainty included contributions from the measured integral data and from the spectrum and cross sections used to obtain the calculated integral data. Within the uncertainty and correlation specifications for the input spectrum and dosimeter cross sections, the least-squares-adjustment analysis indicated a high degree of consistency between the measured integral data and the ENDF/B-V dosimeter cross sections for all reactions except 10 B

Neutron radiography with ultracold neutrons

International Nuclear Information System (INIS)

Bates, J.C.

1981-01-01

The neutron transmission factor of very thin films may be low if the neutron energy is comparable to the pseudo-potential of the film material. Surprisingly, perhaps, it is relatively easy to obtain neutrons with such low energies in sufficient numbers to produce neutron radiographs. (orig.)

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.

Reactor neutron dosimetry

International Nuclear Information System (INIS)

Najzer, M.; Pauko, M.; Glumac, B.; Acquah, I.N.; Moskon, F.

1977-01-01

An analysis of requirements and possibilities for experimental neutron spectrum determination during the reactor pressure vessel surveil lance programme is given. Fast neutron spectrum and neutron dose rate were measured in the Fast neutron irradiation facility of our TRIGA reactor. It was shown that the facility can be used for calibration of neutron dosimeters and for irradiation of samples sensitive to neutron radiation. The investigation of the unfolding algorithm ITER was continued. Based on this investigations are two specialized unfolding program packages ITERAD and ITERGS written this year. They are able to unfold data from activation detectors and NaI(T1) gamma spectrometer respectively

A CaS : Ce, Sm-based dosimeter for online dosimetry measurement

International Nuclear Information System (INIS)

Sun Yurun; Chen Zhaoyang; Fan Yanwei; Yan Shiyou; He Chengfa

2011-01-01

A film dosimeter based on optically stimulated luminescence (OSL) material of CaS : Ce, Sm was developed for online irradiation dosimetry measurement. The stimulation is provided by a laser with a wavelength of 980 nm, and the OSL luminescence is collected by a photodiode. Using 60 Co γ-rays, we investigated the dosimetry characteristic of the dosimeter at different dose rates and total doses. The real-time detection results showed that the OSL signals versus total ionizing dose exhibited a good linearity in a dose range of 0.1-185 Gy. (authors)

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)

A preliminary investigation of the EBT2 radiochromic films response to low energy fast neutrons

Energy Technology Data Exchange (ETDEWEB)

Aydarous, Abdulkadir, E-mail: Aydarous@gmail.com [Physics Department, Faculty of Science, Taif University, Al-Hawiah, Taif, PO Box 888 (Saudi Arabia); Faculty of Energy Systems and Nuclear Science, University of Ontario Institute of Technology, 2000 Simcoe St North, Oshawa, ON, L1H 7K4 (Canada); Aslam [Faculty of Energy Systems and Nuclear Science, University of Ontario Institute of Technology, 2000 Simcoe St North, Oshawa, ON, L1H 7K4 (Canada); Waker, Anthony [Faculty of Energy Systems and Nuclear Science, University of Ontario Institute of Technology, 2000 Simcoe St North, Oshawa, ON, L1H 7K4 (Canada); Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON, L8S 4M1 (Canada)

2012-07-15

EBT2 radiochromic films were used to study the relative dose distribution of the neutron field. The correlation between the beam current and the optical density showed good linear dependence with a correlation coefficient exceeding 98%. At any given beam energy, neutron dose rates can be changed by a factor of 40 without changing the neutron spectrum. This result is consistent with what was found by the Tissue Equivalent Proportional Counter measurements. The uniformity of the neutron field was inspected by the optical density profile of the exposed film. - Highlights: Black-Right-Pointing-Pointer Developing a 2D image for neutron field. Black-Right-Pointing-Pointer Investigation of EBT2 sensitivity to neutrons. Black-Right-Pointing-Pointer Studying the effect of irradiation parameters (beam energy and beam current) to the measured optical density.

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

International Nuclear Information System (INIS)

Giaddui, Tawfik; Cui Yunfeng; Galvin, James; Yu Yan; Xiao Ying

2013-01-01

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

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).

Experimental verification of a new neutron spectrometer for environmental dosimetry and area; Verficiacion experimental de un nuevo espectrometro de neutrones para dosimetria ambiental y de area

Energy Technology Data Exchange (ETDEWEB)

Gomez-Ros, J. M.; Romero, A.; Begogini, R.; Esposito, A.; Moraleda, M.; Lagares, J. I.; Sansaloni, F.; Arce, P.; Llop, J.

2011-07-01

In this communication, we present experimental results with a new neutron spectrometer, developed jointly by the Radiation Dosimetry Unit of CIEMAT Unita di Fisica and INFN-LNF Sanitary (Italy), consisting of a polyethylene moderating sphere detectors thermal neutrons (paired thermoluminescent dosimeters and activation foils) located in different positions. The device configuration and distribution of dosimeters are designed to elicit a response in a nearly isotropic up to 20 MeV energy range. (Author)

Neutron personnel dosimetry considerations for fusion reactors

International Nuclear Information System (INIS)

Barton, T.P.; Easterly, C.E.

1979-07-01

The increasing development of fusion reactor technology warrants an evaluation of personnel neutron dosimetry systems to aid in the concurrent development of a radiation protection program. For this reason, current state of knowledge neutron dosimeters have been reviewed with emphasis placed on practical utilization and the problems inherent in each type of dosimetry system. Evaluations of salient parameters such as energy response, latent image instability, and minimum detectable dose equivalent are presented for nuclear emulsion films, track etch techniques, albedo and other thermoluminescent dosimetry techniques, electrical conductivity damage effects, lyoluminescence, thermocurrent, and thermally stimulated exoelectron emission. Brief summaries of dosimetry regulatory requirements and intercomparison study results help to establish compliance and recent trends, respectively. Spectrum modeling data generated by the Neutron Physics Division of Oak Ridge National Laboratory for the Princeton Tokamak Fusion Test Reactor (TFTR) Facility have been analyzed by both International Commission on Radiological Protection fluence to dose conversion factors and an adjoint technique of radiation dosimetry, in an attempt to determine the applicability of current neutron dosimetry systems to deuterium and tritium fusion reactor leakage spectra. Based on the modeling data, a wide range of neutron energies will probably be present in the leakage spectra of the TFTR facility, and no appreciable risk of somatic injury to occupationally exposed workers is expected. The relative dose contributions due to high energy and thermal neutrons indicate that neutron dosimetry will probably not be a serious limitation in the development of fusion power

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

International Nuclear Information System (INIS)

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

2015-01-01

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

Angular dependence of the MOSFET dosimeter and its impact on in vivo surface dose measurement in breast cancer treatment.

Science.gov (United States)

Qin, S; Chen, T; Wang, L; Tu, Y; Yue, N; Zhou, J

2014-08-01

The focus of this study is the angular dependence of two types of Metal Oxide Semiconductor Field Effect Transistor (MOSFET) dosimeters (MOSFET20 and OneDose/OneDosePlus) when used for surface dose measurements. External beam radiationat different gantry angles were delivered to a cubic solid water phantom with a MOSFET placed on the top surface at CAX. The long axis of the MOSFET was oriented along the gantry axis of rotation, with the dosimeter (bubble side) facing the radiation source. MOSFET-measured surface doses were compared against calibrated radiochromic film readings. It was found that both types of MOSFET dosimeters exhibited larger than previously reported angular dependence when measuring surface dose in beams at large oblique angles. For the MOSFET20 dosimeter the measured surface dose deviation against film readings was as high as 17% when the incident angle was 72 degrees to the norm of the phantom surface. It is concluded that some MOSFET dosimeters may have a strong angular dependence when placed on the surface of water-equivalent material, even though they may have an isotropic angular response when surrounded by uniform medium. Extra on-surface calibration maybe necessary before using MOSFET dosimeters for skin dose measurement in tangential fields.

Investigation of a new generation of dosimeter based on BaFBr(Eu)-type photostimulable sensors: characterization and application to environmental and individual dosimetry

International Nuclear Information System (INIS)

Mouhssine, Dounia

2004-01-01

This research thesis deals with the characterization and implementation of a new dosimetry system for alpha, gamma and neutron radiations in compliance with new recommendations. This system is based on the use of photostimulable sensors (radio-luminescent films) which have some benefits with respect to conventional dosimeters. After an overview of radiation-matter interaction processes and of the main physical, radiometric and dosimetric quantities used in the field of radiation protection and dosimetry, the author presents various radiation detection methods based on semiconductors, on solid sensors of nuclear traces, and on luminophores. She presents and discusses experimental results obtained with the herein developed dosimeters, as well as the investigation of several parameters. Experimental results are compared with computation results obtained with the MCNP simulation code (Monte Carlo N Particles). Then, after an overview of radon (properties, origin, health risks) and of different active and passive methods of measurement of radon concentrations and of its descendants, the authors comments the first feasibility tests of this system for the detection of a radon signal

Scanning tunneling spectroscopy on neutron irradiated MgB2 thin films

International Nuclear Information System (INIS)

Di Capua, Roberto; Salluzzo, Marco; Vaglio, Ruggero; Ferdeghini, Carlo; Ferrando, Valeria; Putti, Marina; Xi Xiaoxing; Aebersold, Hans U.

2007-01-01

Neutron irradiation was performed on MgB 2 thin films grown by hybrid physical chemical vapor deposition. Samples irradiated with different neutron fluences, having different critical temperatures, were studied by scanning tunneling spectroscopy in order to investigate the effect of the introduced disorder on the superconducting and spectroscopic properties. A monotonic increase of the π gap with increasing disorder was found

The neutron and low-energy gamma operational dosimetry in Melox plant

International Nuclear Information System (INIS)

Devita, A.D.

2006-01-01

M.E.L.O.X., subsidiary of A.R.E.V.A., produce M.O.X. fuels, a mixture of uranium and plutonium oxides. With the use in the process of plutonium oxide, there is a risk of external exposure to neutrons and low -energy gamma rays. By their characteristics, both these types of radiation are difficult to measure. The difficulty in measuring neutron doses lies in the fact that the fluence -to-dose equivalent conversion factor varies with the neutron energy level. In low -energy gamma (between 20 and 60 keV) dose measurement, the problem is detection using an electronic system. Just some years ago, very few industrial players were tempted to develop dosimeters in these areas in view of the poor demand and market prospects. Furthermore, radiation protection specialists needed a highly functional and robust direct reading dosimeters or, in other words, a device that was simple, reliable, inexpensive, small, and quick and easy to use in a wide range of working environments that could vary in terms of both the workstation and external exposure. In addition, at sites such as Melox, where company employees work alongside personnel from outside companies, the same types of dosimeters must be used so that dose -related data can be managed globally in one data base. Two technical solutions are available for neutron operational dosimetry - spectrometer-dosimeters and calibration dosimeters. Melox has opted for the use of calibration dosimeters. The reasons for this choice (technical, financial and organizational criteria) are given in this presentation. Before and during the various campaigns of M.O.X. fuels, the spectral characteristics relating to neutron fluence at different workstations and representative of personnel exposure levels were determined. A reference spectrometer was then used to determine the transfer function between fluence and dose in order to calibrate passive and operational dosimeters appropriately.The methodology to be set up should guarantee good

Alarm pocket dosimeter

Energy Technology Data Exchange (ETDEWEB)

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

1975-04-01

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

SU-F-T-550: Radiochromic Plastic Thin Sheet Dosimeter: Initial Performance

Energy Technology Data Exchange (ETDEWEB)

Jordan, K [London Regional Cancer Program, London, ON (United Kingdom); Adamovics, J [John Adamovics, Skillman, NJ (United States)

2016-06-15

Purpose: Thin sheets, of a high sensitivity formulation of radiochromic dosimeter, Presage were prepared and evaluated for optical readout. Methods: Sheets of radiochromic polyurethane, 12 cm long, 10 cm wide and 0.2 cm thick were prepared with leuco crystal violet as the reporter molecule. Sample transmission was evaluated at a wavelength of 590 nm with in-house constructed instruments: optical cone beam laser CT scanner, fixed and scanning spot densitometers. Sample sequential irradiations to a total dose of 40 Gy were conducted with a modified, Theratron 60, cobalt radiotherapy machine at dose rates of 1 or 0.25 Gy per minute. Exposure to ambient and readout light was minimized to limit background photochromic signals. Samples were stored at 4°C. Optical activity was assessed from linearly polarized transmission images. Comparison sensitivity measurements with EBT3 film were conducted. Results: Samples were transparent, smooth and pale purple before irradiation. Radiochromic reaction was completed in less than 5 minutes. A linear dose response with a sensitivity of 0.5 cm-1Gy-1 was observed. Micrometer measurements found sheet thickness variations up to 20%. Uniform dose, 2 Gy attenuation images, correlated with local sheet thicknesses. Comparable measurements with EBT3 film were 3 times more sensitive at 1 Gy but above 15 Gy, EBT3 film had lower sensitivity than 0.2 cm thick Presage sheet dosimeter due to its non-linear response. Conclusion: Dose sensitivity provided a 10% decrease in transmission for a 1 Gy dose. Improvements in mold design are expected to allow production of sheets with less than 5% variation in thickness. Above, 10 Gy, Presage sheet dosimeter performance expected to exceed EBT3 film based on linearity, sensitivity, transparency and smoothness of samples. J Adamovics is owner of Heuris Inc.

Method of measuring neutron spectra in JMTR exclusively used for irradiation and their evaluation

International Nuclear Information System (INIS)

Sakurai, Kiyoshi

1983-01-01

In the core of the Japan Materials Testing Reactor, about 60 capsules are irradiated. These are the material capsules for irradiating reactor materials, the fuel capsules for irradiating reactor fuel, the RI capsules for producing radioisotopes and so on. In the irradiation experiment using a reactor, the information on the neutron fluence is indispensable, and the neutron fluence in the irradiated specimen part is evaluated with a dosimeter or the nuclear calculation for the core of the JMTR. At the time of irradiating reactor materials, the dosimeter Fe-54 (n,p) Mn-54 is generally used for evaluating the neutron fluence more than 1 MeV. In the case of fuel irradiation, the thermal neutron fluence is evaluated with the dosimeter Co-59 (n,γ) Co-60. It is important to examine in detail neutron spectra by both calculation and experiment in the reactors exclusively used for irradiation such as the JMTR. The neutron irradiation field in the JMTR, neutron spectrum measuring experiment, the neutron flux monitors for standardizing data, the measurement of X-ray and gamma ray, neutron guess spectrum, the compilation of neutron cross section for SAND 2, and the unfolding of neutron spectra are reported. The degree of agreement of the neutron fluence more than 1 MeV by measurement and calculation was +- 10 to 20 %. (Kako, I.)

Calibration of a TLD system to estimate personal doses in fields of gamma-neutrons radiation

International Nuclear Information System (INIS)

Villegas, E.N.; Somarriba, S.I.

2016-01-01

Currently Nicaragua has no personal neutron dosimetry system. The calibration of a batch of albedo neutron dosimeters consisting of two pairs of "6LiF and "7LiF (Mg, Ti) detectors was done. The dosimeter and reader sensitivities were obtained using a "1"3"7Cs source, and a neutron calibration factor was found with a "2"4"1AmBe source. Reproducibility and homogeneity tests were performed, and the detection limit of the system was determined. This calibration will allow the beginning of neutron personal monitoring in the country. (author)

Thin film CdTe based neutron detectors with high thermal neutron efficiency and gamma rejection for security applications

Energy Technology Data Exchange (ETDEWEB)

Smith, L.; Murphy, J.W. [Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Kim, J. [Korean Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of); Rozhdestvenskyy, S.; Mejia, I. [Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Park, H. [Korean Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of); Allee, D.R. [Flexible Display Center, Arizona State University, Phoenix, AZ 85284 (United States); Quevedo-Lopez, M. [Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Gnade, B., E-mail: beg031000@utdallas.edu [Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States)

2016-12-01

Solid-state neutron detectors offer an alternative to {sup 3}He based detectors, but suffer from limited neutron efficiencies that make their use in security applications impractical. Solid-state neutron detectors based on single crystal silicon also have relatively high gamma-ray efficiencies that lead to false positives. Thin film polycrystalline CdTe based detectors require less complex processing with significantly lower gamma-ray efficiencies. Advanced geometries can also be implemented to achieve high thermal neutron efficiencies competitive with silicon based technology. This study evaluates these strategies by simulation and experimentation and demonstrates an approach to achieve >10% intrinsic efficiency with <10{sup −6} gamma-ray efficiency.

Temperature dependence of gafchromic MD-55 dosimeter

International Nuclear Information System (INIS)

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

1997-01-01

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

Personnel-dosimetry intercomparison studies at the Oak Ridge National Laboratory

International Nuclear Information System (INIS)

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

1982-01-01

Since 1974, seven annual personnel dosimetry intercomparison studies have been conducted at the Oak Ridge National Laboratory using the Health Physics Reactor. These studies have produced more than 2000 measurements by 72 participating organizations of neutron and gamma dose equivalents between 0.1 to 15.0 mSv in six mixed radiation fields. The relative performance of three basic types of personnel neutron dosimeters (nuclear emulsion film, thermoluminescent, and track-etch) and two basic types of gamma dosimeters (film and thermoluminescent) was assessed based on experimental results obtained during the seven intercomparisons

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.)

Experimental study and Monte Carlo modeling of operational quantities in metrology of ionizing radiation: application to neutrons dosimetry by radio-photoluminescence

International Nuclear Information System (INIS)

Salem, Youbba-Ould

2014-01-01

We characterize a passive dosimeter capable of measuring both fast and thermal neutrons for ambient and personal dosimetry. These neutrons can be detected in a mixed neutron-gamma field with appropriate converters (polyethylene for fast neutrons, cadmium for thermal neutrons). Monte Carlo simulations with MCNPX helped with the geometrical conception of the dosimeter and the choice of materials. The responses of the RPL dosimeter to these neutrons are linear in H * (10) and H p (10) with detection limits of 2 mSv for fast neutrons and 0.19 mSv for thermal neutrons. The angular dependencies are satisfactory according to the ISO 21909 norm. A calibration factor of (9.5 ± 0.5)*10 -2 mSv.cm 2 /RPL signal is obtained to the fast neutrons of the IPHC's 241 Am-Be calibrator. This factor is (9.7 ± 0.3)*10 -3 mSv.cm 2 /RPL signal for the thermalized neutrons. (author)

A radiation-sensitive monomer of 2,4-hexadiyn-1,6-bis(p-toluene sulphonyl urethane) in PVA as a radiochromic film dosimeter

Science.gov (United States)

Soliman, Yasser S.; Abdel-Fattah, A. A.; Hamed, A. A.; Bayomi, A. M. M.

2018-03-01

A conjugated monomer 2,4-hexadiyn-1,6-bis(p-toluene sulphonyl urethane) (HDTU) was synthesized. Thereafter, it was incorporated into polyvinyl alcohol (PVA), and coated on self-adhesive sheet, thus to prepare film dosimeters. The monomer and films were analyzed using X-ray diffraction (XRD), FTIR spectroscopy and specular reflectance colorimetry. This monomer polymerizes in the films by radiation and turns progressively blue in proportion to absorbed dose, indicating the formation of π-conjugated colored poly-HDTU. Color development was investigated at 480 nm and 610 nm for dose monitoring ranging from 10 Gy to 15 kGy. HDTU in PVA film is highly ordered and crystalline and, upon irradiation, it forms a semi-crystalline polymer with nearly the same interplanar distances as the monomer, indicating the occurrence of topochemical polymerization. During irradiation, polymerization of the monomer is nearly independent of humidity in the range of 0-53% and temperature in the range of 25-45 °C. The uncertainty of this system is 5.16% at 95% confidence level.

Measurement of multi-slice computed tomography dose profile with the Dose Magnifying Glass and the MOSkin radiation dosimeter

International Nuclear Information System (INIS)

Lian, C.P.L.; Wong, J.H.D.; Young, A.; Cutajar, D.; Petasecca, M.; Lerch, M.L.F.; Rosenfeld, A.B.

2013-01-01

This study describes the application of two in-house developed dosimeters, the Dose Magnifying Glass (DMG) and the MOSkin dosimeter at the Centre for Medical Radiation Physics, University of Wollongong, Australia, for the measurement of CT dose profiles for a clinical diagnostic 16-slice MSCT scanner. Two scanner modes were used; axial mode and helical mode, and the effect of varying beam collimation and pitch was studied. With an increase in beam collimation in axial mode and an increase of CT pitch in helical mode, cumulative point dose at scanner isocentre decreased while FWHM increased. There was generally good agreement to within 3% between the acquired dose profiles obtained by the DMG and the film except at dose profile tails, where film over-responded by up to 30% due to its intrinsic depth dose dependence at low doses. -- Highlights: ► This study shows the CT beam profiles acquired with our institution's detectors. ► The DMG is a relative dosimeter calibrated to absolute MOSkin readings. ► There was good agreement between dose profiles acquired by the DMG and the film

Calibration and automatic counting in a neutrons dosimeter

International Nuclear Information System (INIS)

Tavera-Davila, M.L.

1991-01-01

Over the past decade, the majority of improvements in spectrometry have not come from improved detectors but from better computing facilities, in Folding codes, and nuclear data. However several types of passive neutron detectors have the potential for development into crude, low resolution spectrometers, to be worn by individuals, making them attractive to be subject of more time of investigation. This thesis contributes to the understanding of the properties of solid state nuclear tracks (SSNTD) in order to use them in neutron dosimetry and spectrometry. In the first chapter the basic principles on neutron interaction with matter and some relevant considerations about detection and dosimetry are presented. The third chapter deals with detection properties of solid state nuclear track detectors (SSNTD). Calibration methods are presented for three different applications, detection of heavy ions, radon and neutrons. In chapter 4, some equations are derived which predict the whole efficiency formation of thin plastic detectors as a function of range, angle, and type of inciding particle as well as residual thickness. Using experimental data on proton registration properties in thin plastic detectors and the former derived equations, mathematical expressions are developed to predict the sparking counting efficiency for recoll protons and trions produced by neutrons in SSNTD. Chapter five deals with the comparison between experimental results and theoretical results of chapter 4. In chapter 6 experimental optimum parameters for electrochemical etching of thin plastic detectors are presented. The electrochemical etching efficiency is compared with the spark countering efficiency obtained in chapter 5. In chapter 7, general comments on applications to neutron dosimetry are presented. (Author)

Neutron measurements at nuclear power reactors [55

CERN Document Server

Scherpelz, R I

2002-01-01

Staff from the Pacific Northwest National Laboratory (operated by Battelle Memorial Institute), have performed neutron measurements at a number of commercial nuclear power plants in the United States. Neutron radiation fields at light water reactor (LWR) power plants are typically characterized by low-energy distributions due to the presence of large amounts of scattering material such as water and concrete. These low-energy distributions make it difficult to accurately monitor personnel exposures, since most survey meters and dosimeters are calibrated to higher-energy fields such as those produced by bare or D sub 2 O-moderated sup 2 sup 5 sup 2 Cf sources. Commercial plants typically use thermoluminescent dosimeters in an albedo configuration for personnel dosimetry and survey meters based on a thermal-neutron detector inside a cylindrical or spherical moderator for dose rate assessment, so their methods of routine monitoring are highly dependent on the energy of the neutron fields. Battelle has participate...

Investigation of dose distribution in mixed neutron-gamma field of boron neutron capture therapy using N isopropylacrylamide gel

Energy Technology Data Exchange (ETDEWEB)

Bavarmegin, Elham; Sadremomtaz, Alireza [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of); Khalafi, Hossein; Kasesaz, Yaser [Dept. of Physics, University of Guilan, Rasht (Iran, Islamic Republic of); Khajeali, Azim [Medical Education Research Center, Tabriz (Iran, Islamic Republic of)

2017-02-15

Gel dosimeters have unique advantages in comparison with other dosimeters. Until now, these gels have been used in different radiotherapy techniques as a reliable dosimetric tool. Because dose distribution measurement is an important factor for appropriate treatment planning in different radiotherapy techniques, in this study, we evaluated the ability of the N-isopropylacrylamide (NIPAM) polymer gel to record the dose distribution resulting from the mixed neutron-gamma field of boron neutron capture therapy (BNCT). In this regard, a head phantom containing NIPAM gel was irradiated using the Tehran Research Reactor BNCT beam line, and then by a magnetic resonance scanner. Eventually, the R2 maps were obtained in different slices of the phantom by analyzing T2-weighted images. The results show that NIPAM gel has a suitable potential for recording three-dimensional dose distribution in mixed neutron-gamma field dosimetry.

Effect of Gamma Rays on Fast Neutron Registration in CR-39

CERN Document Server

Kobzev, A P; El-Halem, A A; Abdul-Ghaphar, U S; Salama, T A

2002-01-01

A set of CR-39 plastic detectors with front PE radiator was exposed to Am-Be neutron source, which has an emission rate of 0.86\\cdot 10^{7} sec^{-1}, and the neutron dose equivalent rate 1 m apart from the source is equal to 11 mrem/hr. Another set of samples was irradiated by a neutron dose of 4 rem, then exposed to different gamma-ray doses using ^{60}Co source. It was found that the track density grows with the increase of neutron dose and etching time. It was also found that the bulk etching rate V_{B}, the track diameter and the sensitivity of the CR-39 plastic detector with respect to the neutron irradiation increased with increasing gamma-ray dose in the range 1?10 Mrad. These results show that CR-39 can be considered as a promising fast neutron dosimeter and gamma-ray dosimeter.

Radiochromic film containing methyl viologen for radiation dosimetry

DEFF Research Database (Denmark)

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

2007-01-01

Poly(vinyl alcohol) (PVA) films containing methyl viologen (MV2+) that colours blue upon exposure to ionizing radiation were investigated as possible dosimeters for use in radiation processing applications. In order to find the most suitable composition of the PVA-MV2+ film, different......, humidity and temperature on the response of the PVA-MV2+ dosimeter film have been studied under laboratory conditions. We conclude that the PVA film containing MV2+ is a promising tool for the absorbed dose measurements in several industrial applications of ionizing radiations. (C) 2007 Elsevier Ltd. All...

Neutron personnel dosimetry

International Nuclear Information System (INIS)

Griffith, R.V.

1982-01-01

The measurement of neutron exposures to personnel is an issue that has received increased attention in the last few years. It is important to consider key aspects of the whole dosimetry system when developing dose estimates. This begins with selection of proper dosimeters and survey instruments, and extends through the calibration methods. One must match the spectral response and sensitivity of the dosimeter to the spectral characteristics of the neutron fields. Threshold detectors that are insensitive to large fractions of neutrons in the lower energy portion of reactor spectra should be avoided. Use of two or more detectors with responses that complement each other will improve measurement quality. It is important to understand the spectral response of survey instruments, so that spectra which result in significant overresponse do not lead to overestimation of dose. Calibration sources that do not match operational field spectra can contribute to highly erroneous results. In those situations, in-field calibration techniques should be employed. Although some detection developments have been made in recent years, a lot can be done with existing technology until fully satisfactory, long term solutions are obtained

Fast neutron personnel dosimetry by CR-39 plastics a new electrochemical etching procedure

International Nuclear Information System (INIS)

Djeffal, S.

1984-07-01

In the first part of this work a brief description of solid state nuclear track detectors, the principles of track registration and the different reading techniques are given. In the experimental part of the present work we systematically analysed different etching procedures and set a new electrochemical etching method, which enables us to develop a new fast neutron dosimeter. This fast neutron dosimeter makes possible the measurement of low neutron doses in the energy range from 10 Kev to 20 Mev with a reasonably flat energy response. These new developments are very attractive in personnel neutron dosimetry where nuclear emulsions are still used despite their insensitivity to neutron energies down to 500 Kev (i.e. the energy range one often encounters around nuclear facilities)

Scanning tunneling spectroscopy on neutron irradiated MgB{sub 2} thin films

Energy Technology Data Exchange (ETDEWEB)

Di Capua, Roberto [University of Napoli and CNR-INFM/Coherentia, Via Cinthia, Naples I-80126 (Italy)], E-mail: rdicapua@na.infn.it; Salluzzo, Marco; Vaglio, Ruggero [University of Napoli and CNR-INFM/Coherentia, Via Cinthia, Naples I-80126 (Italy); Ferdeghini, Carlo [CNR-INFM/LAMIA, Via Dodecaneso 33, Genova I-16146 (Italy); Ferrando, Valeria [CNR-INFM/LAMIA, Via Dodecaneso 33, Genova I-16146 (Italy); Pennsylvania State University, University Park, PA 16802 (United States); Putti, Marina [CNR-INFM/LAMIA, Via Dodecaneso 33, Genova I-16146 (Italy); Xi Xiaoxing [Pennsylvania State University, University Park, PA 16802 (United States); Aebersold, Hans U. [Paul Scherrer Institut, Villigen CH-5232 (Switzerland)

2007-09-01

Neutron irradiation was performed on MgB{sub 2} thin films grown by hybrid physical chemical vapor deposition. Samples irradiated with different neutron fluences, having different critical temperatures, were studied by scanning tunneling spectroscopy in order to investigate the effect of the introduced disorder on the superconducting and spectroscopic properties. A monotonic increase of the {pi} gap with increasing disorder was found.

Interface alloying in multilayer thin films using polarized neutron reflectometry

International Nuclear Information System (INIS)

Basu, Saibal

2013-01-01

Polarized Neutron Reflectometry (PNR) is an excellent tool to probe magnetic depth profile in multilayer thin film samples. In case of multilayer films with alternating magnetic and non-magnetic layers, PNR can provide magnetic depth profile at the interfaces with better than nanometer resolution. Using PNR and Xray Reflectometry (XRR) together one can obtain chemical composition and magnetic structure, viz. magnetic moment density at interfaces in multilayer films. We have used these two techniques to obtain kinetics of alloy formation at the interfaces and the magnetic nature of the alloy at the interfaces in several important thin films with magnetic/non-magnetic bilayers. These include Ni/Ti, Ni/Al and Si/Ni pairs. Results obtained from these studies will be presented in this talk. (author)

Trends of personal dosimetry at atomic power plants

International Nuclear Information System (INIS)

Yamamura, Seini

1998-01-01

The individual dosimetry at the atomic power station is sorted for monthly dosimetry, daily dosimetry and special job dosimetry in high dose circumstance. Film badge (passive dosimeter) can measure gamma dose, beta dose and neutron dose respectively lower than about 0.1 mSv. While workers are in the radiation controlled area, they have to wear the dosimeters and the individual dose is accumulated for every one month. Recently the Silicon semiconductors detecting beta ray and neutron have been developed. With microcircuit technology and these new sensors, new multiple function dosimeter of the card size had been put to practical use. The result of dose measurement obtained by the electronic dosimeter is consistent well with the measurement of usual film badge and new dosimeter can determine the dose as low as 0.01 mSv. The result is stored in the non-volatile memory in the electronic personal dosimeter and held for more than one year without the power supply. The function to read data directly from the memory improves the reliability of the data protection. The realization of the unified radiation control system that uses the electronic personal dosimeter for monthly dosimetry is expected. (J.P.N.)

Fundamentals of Polymer Gel Dosimeters

Science.gov (United States)

McAuley, Kim B.

2006-12-01

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

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

Comparison Study of the Response of Several Passive PDA Based Personal Dosimeter to Gamma and X-Ray Radiation

International Nuclear Information System (INIS)

Cohen, S.; Abraham, A.; Pelled, O.; Tubul, Y.; Kresner, E.; Ashkenazi, A.; Yaar, I.

2014-01-01

In the case of a radiological terror event or a nuclear accident, there is a need to perform a fast and reliable personal dosimetry measurements for first responders and other intervention forces. The dosimeters should be simple, instant and cumulative readout small and lightweight energy independent (iv) wide dose range (v) withstand intense environments cheap, and disposable. In the last decade, two simple dosimeters were presented for radiological emergencies self-indicating radiation alert dosimeters (SIRAD) and (ii) RADview by J.P Labs and M/s RADeCO, respectively. Both dosimeters contain radio-chromic films based on PDA (poly-di-acetylene) material that change the colors in their active window as a function of radiation dose. In the current study, the dose response of SIRAD and RADview personal dosimeters to 137Cs and M150 X-Ray radiation at the range of 0.01-11 Sv is presented. In addition, the environmental, fading effects and usage effects on the response of these dosimeters is evaluated

Development of a semiconductor neutron dosimeter with a PIN diode

International Nuclear Information System (INIS)

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

2004-01-01

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

Fast neutron dosimetry by means of different solid state nuclear track detectors

International Nuclear Information System (INIS)

Spurny, F.; Turek, K.

1977-01-01

The comparative study of three different types of fast neutron dosimeters based on solid state nuclear track detectors is presented; the dosimeters studied were: - microscopic soda glass in contact with 232 Th; - polycarbonate Makrofol E; and - cellulose nitrate Kodak LR 115. All detectors were evaluated by visual counting in a microscope. The authors have studied such properties as the background, angular as well as energetical dependences of detectors. The results obtained show that all studied detectors are suitable for fast neutron dosimetry; their application depends however on the concrete experimental conditions (neutron spectrum, fluence etc.). Both advantages and disadvantages of each of them are presented. (Auth.)

The Effect of Radiator on CR-39 Registration of Fast Neutrons

International Nuclear Information System (INIS)

El-Badrya, B.A.; Hegazya, T.M.; Morsya, A.A.; Zaki, M.F.

2008-01-01

Three different configurations of a personal neutron dosimeter using CR-39 plastic detector were placed in Plastiplast pouch composed from inside to outside of Aluminum ( 27 Al, 40 Ξ m), polyethylene (PE, 20 Ξ m), Cellulose Nitrate (CN, 40 Ξ m). One dosimeter was composed of a CR-39 detector and a PE radiator (1 mm thick), another of two CR-39 detectors with one serving as radiator, and the other of CR-39 alone (without radiator). These dosimeters have been irradiated with fast neutrons of average energy 4.5 MeV with neutron fluence ranging from 5.5 x 10 6 to 0.5 x 10 8 cm - 2 emitted from 241 Am-Be neutron source. The polymeric materials have been chosen on the basis of their hydrogen contents, which are as followed: CR-39, 48%, Polyethylene, 66.7% and CN, 32% by atomic ratio to produce protons via (n, p) elastic scattering with hydrogen and increasing the detection efficiency of CR-39. After irradiation, the dose equivalent response of the detectors has been studied by using conventional etching for two periods, 6h and 8h for these configurations. The thicknesses and compositions of the radiators are chosen so as to suppress the CR-39 response below 4 MeV by preventing the recoils of hydrogen nuclei, out of the hydrogen-rich radiators (PE, CR-39), from reaching the post-etch surface of the detector. Track counting was performed using an automated system. It was found that the dosemeter responses were linear as a function of a neutron equivalent dose and that the CR-39 detector has the same response with radiator or without radiator and thus appears as a promising fast neutron dosimeter. The results are discussed and compared with the literature

Application of the adjoint function methodology for neutron fluence determination

International Nuclear Information System (INIS)

Haghighat, A.; Nanayakkara, B.; Livingston, J.; Mahgerefteh, M.; Luoma, J.

1991-01-01

In previous studies, the neutron fluence at a reactor pressure vessel has been estimated based on consolidation of transport theory calculations and experimental data obtained from in-vessel capsules and/or cavity dosimeters. Normally, a forward neutron transport calculation is performed for each fuel cycle and the neutron fluxes are integrated over the reactor operating time to estimate the neutron fluence. Such calculations are performed for a geometrical model which is composed of one-eighth (0 to 45 deg) of the reactor core and its surroundings; i.e., core barrel, thermal shield, downcomer, reactor vessel, cavity region, concrete wall, and instrumentation well. Because the model is large, transport theory calculations generally require a significant amount of computer memory and time; hence, more efficient methodologies such as the adjoint transport approach have been proposed. These studies, however, do not address the necessary sensitivity studies needed for adjoint function calculations. The adjoint methodology has been employed to estimate the activity of a cavity dosimeter and that of an in-vessel capsule. A sensitivity study has been performed on the mesh distribution used in and around the cavity dosimeter and the in-vessel capsule. Further, since a major portion of the detector response is due to the neutrons originated in the peripheral fuel assemblies, a study on the use of a smaller calculational model has been performed

Eleventh ORNL personnel dosimetry intercomparison study, May 22-23, 1985

International Nuclear Information System (INIS)

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

1986-07-01

The Eleventh Personnel Dosimetry Intercomparison Study was conducted at the Oak Ridge National Laboratory (ORNL) during May 22-23, 1985. Dosimeter badges from 44 participating organizations were mounted on Lucite block phantoms and exposed to four mixed-radiation fields with neutron dose equivalents around 5 mSv and gamma dose equivalents between 0.1 and 0.7 mSv. Results of this study indicated that no participants had difficulty obtaining measurable indication of neutron exposure at the provided dose equivalent levels, and very few had difficulty obtaining indication of gamma exposure at dose equivalents as low as 0.10 mSv. Average neutron results for all dosimeter types were within 20% of reference values with no obvious spectrum dependence. Different dosimeter types (albedo, direct interaction TLD, film, recoil track, and combination albedo-track) with 10 or more reported measurements provided average results within 35% of reference values for all spectra. With regard to precision, about 80% of the reported neutron results had single standard deviations within 10% at the means which indicates that precision is not a problem relative to accuracy for most participants. Average gamma results were greater than reference values by factors of 1.07 to 1.52 for the four exposures with TLD systems being more accurate than film. About 80% of all neutron results and 67% of all gamma results met regulatory standards for measurement accuracy and approximately 70% of all neutron data satisfied national dosimetry accreditation criteria for accuracy plus precision. In general, neutron dosimeter performance observed in this intercomparison was much improved compared to that observed in the prior studies while gamma dosimeter performance was about the same

Neutron dosimetric measurements in shuttle and MIR

International Nuclear Information System (INIS)

Reitz, G.

2001-01-01

Detector packages consisting of thermoluminescence detectors (TLD), nuclear emulsions and plastic track detectors were exposed at identical positions inside MIR space station and on shuttle flights inside Spacelab and Spacehab during different phases of the solar cycle. The objectives of the investigations are to provide data on charge and energy spectra of heavy ions, and the contribution of events with low-energy deposit (protons, electrons, gamma, etc.) to the dose, as well as the contribution of secondaries, such as nuclear disintegration stars and neutrons. For neutron dosimetry 6 LiF (TLD600) and 7 LiF (TLD700) chips were used both of which have almost the same response to gamma rays but different response to neutrons. Neutrons in space are produced mainly in evaporation and knock-on processes with energies mainly of 1-10 MeV and up to several 100 MeV, respectively. The energy spectrum undergoes continuous changes toward greater depth in the attenuating material until an equilibrium is reached. In equilibrium, the spectrum is a wide continuum extending down to thermal energies to which the 6 LiF is sensitive. Based on the difference of absorbed doses in the 6 LiF and 7 LiF chips, thermal neutron fluxes from 1 to 2.3 cm -2 s -1 are calculated using the assumption that the maximum induced dose in TLD600 for 1 neutron cm -2 is 1.6x10 -10 Gy (Horrowitz and Freeman, Nucl. Instr. and Meth. 157 (1978) 393). It is assumed that the flux of high-energy neutrons is at least of that quantity. Tissue doses were calculated taking as a mean ambient absorbed dose per neutron 6x10 -12 Gy cm 2 (for a 10 MeV neutron). The neutron equivalent doses for the above-mentioned fluxes are 52 μGy d -1 and 120 μGy d -1 . In recent experiments, a personal neutron dosimeter was integrated into the dosimeter packages. First results of this dosimeter which is based on nuclear track detectors with converter foils are reported. For future measurements, a scintillator counter with

Characterisation of the epithermal neutron irradiation facility at the Portuguese research reactor using MCNP.

Science.gov (United States)

Beasley, D G; Fernandes, A C; Santos, J P; Ramos, A R; Marques, J G; King, A

2015-05-01

The radiation field at the epithermal beamline and irradiation chamber installed at the Portuguese Research Reactor (RPI) at the Campus Tecnológico e Nuclear of Instituto Superior Técnico was characterised in the context of Prompt Gamma Neutron Activation Analysis (PGNAA) applications. Radiographic films, activation foils and thermoluminescence dosimeters were used to measure the neutron fluence and photon dose rates in the irradiation chamber. A fixed-source MCNPX model of the beamline and chamber was developed and compared to measurements in the first step towards planning a new irradiation chamber. The high photon background from the reactor results in the saturation of the detector and the current facility configuration yields an intrinsic insensitivity to various elements of interest for PGNAA. These will be addressed in future developments. Copyright © 2015 Elsevier Ltd. All rights reserved.

The active personnel dosimeter---APFEL enterprises superheated drop detector

International Nuclear Information System (INIS)

Ipe, N.E.; Donahue, R.J.; Busick, D.D.

1991-03-01

The Active Personnel Dosimeter (APD) provides a digital readout of events caused by neutrons interacting with superheated liquid droplets. The droplets are suspended in a gel held in a replaceable cartridge. Upon neutron interaction, the superheated droplet vaporizes, forming a bubble. The sound produced in this process is recorded by transducers that sense the accompanying pressure pulse. The APD electronically discriminates against spurious noise and vibration. Studies with the production prototype APDs indicate that the detector response is linear up to about 0.40 mSv, with large variations sometimes from predicted values and between cartridges at higher dose equivalents. The response to standard neutron sources (bare 252 Cf, PuBe, PuB, PuF, PuLi) is reported and compared with the expected response. Unirradiated cartridges self-nucleate when heated to temperatures of 46 degrees C. The APD is insensitive to low-energy photons but responds to high-energy photons and electrons. 8 refs., 2 figs., 3 tabs

Investigation of gamma-ray sensitivity of neutron detectors based on thin converter films

Energy Technology Data Exchange (ETDEWEB)

Khaplanov, A; Hall-Wilton, R [European Spallation Source, P.O Box 176, SE-22100 Lund (Sweden); Piscitelli, F; Buffet, J-C; Clergeau, J-F; Correa, J; Esch, P van; Ferraton, M; Guerard, B [Institute Laue Langevin, Rue Jules Horowitz, FR-38042 Grenoble (France)

2013-10-15

Currently, many detector technologies for thermal neutron detection are in development in order to lower the demand for the rare {sup 3}He gas. Gas detectors with solid thin film neutron converters readout by gas proportional counter method have been proposed as an appropriate choice for applications where large area coverage is necessary. In this paper, we investigate the probability for {gamma}-rays to generate a false count in a neutron measurement. Simulated results are compared to measurement with {sup 10}B thin film prototypes and a {sup 3}He detector. It is demonstrated that equal {gamma}-ray rejection to that of {sup 3}He tubes is achieved with the new technology. The arguments and results presented here are also applicable to gas detectors with converters other than solid {sup 10}B layers, such as {sup 6}Li layers and {sup 10}BF{sub 3} gas.

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

ΔOSI: a prototype microstrip dosimeter for characterization of medical radiotherapy and radiosurgery systems

International Nuclear Information System (INIS)

Redondo-Fernandez, I.; Buttar, C.; Walsh, S.; Manolopoulos, S.; Homer, J.M.; Young, S.; Conway, J.

2006-01-01

As the technology for medical radiotherapy and radiosurgery evolves, there is a growing need for dosimeters capable of measuring dose distributions on-line with submillimeter spatial resolution, both for facility commissioning and patient-related quality assurance. We have designed and built a high spatial resolution dosimeter based on silicon micro-strip technology for characterization of small radiotherapy and radiosurgery fields. The aim is to provide relative dosimetry measurement with film-like spatial resolution and to be able to resolve the temporal evolution. Following the description of the prototypes, first beam test results of a 250 μm pitch, 128 channels prototype with X-rays in a clinical 6 MV accelerator are presented. The device demonstrated good dosimetric capabilities when compared to reference measurements made with ionization chambers and agrees with radiographic film in the steep dose gradient region produced by the collimator edge

Orientation of crystals in alanine dosimeter assessed by DRS, as seen in EPR spectra evaluation

International Nuclear Information System (INIS)

Grazyna Przybytniak; Zagorski, Z.P.

1996-01-01

The alanine dosimeter made for evaluation by diffuse light reflection spectrophotometry (ALA/DRS) does not show the effect of orientation of crystals. Supposed deviation from random orientation has been investigated by EPR spectroscopy. EPR investigation shows that in spite of the very fine size of L-alanine crystals, they are oriented in thin layers of the polyethylene matrix. Specially prepared films with deliberately well oriented crystals have confirmed this observation. Our ALA/DRS dosimeter can be evaluated by the EPR method for the concentration of free radicals, providing that the dominating crystal orientation in the dosimetric film is indicated on it as an arrow, and the sample is inserted into the magnetic cavity always in the same orientation as has been done during the calibration operation. (author). 6 refs., 2 figs

Neutron reflectometry

DEFF Research Database (Denmark)

Klösgen-Buchkremer, Beate Maria

2014-01-01

of desired information. In the course, an introduction into the method and an overview on selected instruments at large scale facilities will be presented. Examples will be given that illustrate the potential of the method, mostly based on organic films. Results from the investigation of layered films......Neutron (and X-ray) reflectometry constitute complementary interfacially sensitive techniques that open access to studying the structure within thin films of both soft and hard condensed matter. Film thickness starts oxide surfaces on bulk substrates, proceeding to (pauci-)molecular layers and up...... films or films with magnetic properties. The reason is the peculiar property of neutron light since the mass of a neutron is close to the one of a proton, and since it bears a magnetic moment. The optical properties of matter, when interacting with neutrons, are described by a refractive index...

Refraction of polarized neutrons on the boundary in thick magnetic film FeAlSi

Energy Technology Data Exchange (ETDEWEB)

Aksenov, V L; Kozhevnikov, S V; Nikitenko, Yu V [Joint Inst. for Nuclear Research, Dubna (Russian Federation). Frank Lab. of Neutron Physics

1999-07-01

Complete text of publication follows. Refraction of polarized neutrons in multilayer structure FeAlSi(20 mkm)/Cr(0.05 mkm)/CaTiO{sub 3}(1000 mkm) has been investigated. An external magnetic field was applied under an angle to the sample surface. Refraction on themagnetic boundaries of two types has been investigated. First type is the boundary vacuum-magnetic film. Second type is magnetic film - non-magnetic substrate CaTiO{sub 3} (thin non-magnetic Cr layer doesn't refract the beam). On the boundary there are spin-flip and beam-splitting. Four spatial splitted beams were observed for different spin transitions on each type of the boundary: '+-', '++', '-+' and '--'. From the experimental values of the glancing angles of refracted beam the following parameters has been derives: the nuclear potentials of the magnetic film and the non-magnetic substrate, the magnitude and the direction of a magnetic induction in the magnetic film. It has been shown that the method of refractometry of polarized neutrons can be used for investigation of thick (about mkm) magnetic films. (author)

Summary of the recent conference on thin-film neutron optical devices

International Nuclear Information System (INIS)

Majkrzak, C.F.

1989-01-01

The proceedings of the conference of the International Society for Optical Engineering on Thin-Film Neutron Optical Devices: Mirrors, Supermirrors, Multilayer Monochromators, Polarizers and Beam Guides, which was held in San Diego, California in August, 1988, are summarized here. 2 refs

Considerations in the application of the electronic dosimeter to dose of record

International Nuclear Information System (INIS)

Swinth, K.L.

1997-12-01

This report describes considerations for application of the electronic dosimeter (ED) as a measurement device for the dose of record (primary dosimetry). EDs are widely used for secondary dosimetry and advances in their reliability and capabilities have resulted in interest in their use to meet the needs of both primary and secondary dosimetry. However, the ED is an active device and more complex than the thermoluminescent and film dosimeters now in use for primary dosimetry. The user must evaluate the ED in terms of reliability, serviceability and radiations detected its intended application(s). If an ED is selected for primary dosimetry, the user must establish methods both for controlling the performance of the ED to ensure long term reliability of the measurements and for their proper use as a primary dosimeter. Regulatory groups may also want to develop methods to ensure adequate performance of the ED for dose of record. The purpose of the report is to provide an overview of considerations in the use of the ED for primary dosimetry. Considerations include recognizing current limitations, type testing of EDs, testing by the user, approval performance testing, calibration, and procedures to integrate the dosimeter into the users program

Use of Ukrainian semiconductor dosimeters in a CERN particle accelerator field

Science.gov (United States)

Rosenfeld, A.; Khivrich, V.; Kuts, V.; Tavlet, M.; Malfante, L.; Munoz-Ferrada, C.

1994-08-01

The results of the application of p-i-n and MOS dosimeters in the PS-ACOL Irradiation Facility (PSAIF) at CERN for separate measurements of gamma dose and fast neutron fluences are presented. The mixed gamma-neutron field was due to 26 GeV protons hitting an irridium target, yielding an instantaneous dose rate of approximately 3.10(sup 5) Gy/s. Good agreement with calibration curves is found for MOS in a (sup 60)Co gamma source as well as for p-i-n sensors in a neutron reactor spectrum with mean energy of 1 MeV. Experimental results from PSAIF are presented and pulse current injection annealing of p-i-n diodes is considered. Such sensors are very convenient for on-line separated total dose measurements in mixed gamma-neutron radiation fields, as well as for radiation hardness testing of electronic components on irradiation facilities, and could be installed near the detector area of LHC.

Passive radon daughter dosimeters

International Nuclear Information System (INIS)

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

1986-03-01

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

Light-emitting dendrimer film morphology: A neutron reflectivity study

Science.gov (United States)

Vickers, S. V.; Barcena, H.; Knights, K. A.; Thomas, R. K.; Ribierre, J.-C.; Gambino, S.; Samuel, I. D. W.; Burn, P. L.; Fragneto, Giovanna

2010-06-01

We have used neutron reflectivity (NR) measurements to probe the physical structure of phosphorescent dendrimer films. The dendrimers consisted of fac-tris(2-phenylpyridyl)iridium(III) cores, biphenyl-based dendrons (first or second generation), and perdeuterated 2-ethylhexyloxy surface groups. We found that the shape and hydrodynamic radius of the dendrimer were both important factors in determining the packing density of the dendrimers. "Cone" shaped dendrimers were found to pack more effectively than "spherical" dendrimers even when the latter had a smaller radius. The morphology of the films determined by NR was consistent with the measured photoluminescence and charge transporting properties of the materials.

CAP vessel monitoring. Programme, measurement and neutron calculation

International Nuclear Information System (INIS)

Farrugia, J.M.; Nimal, J.C.; Totth, B.; Lloret, R.; Perdreau, R.

1982-03-01

Starting with the design of the CAP (Prototype Advanced NSSS), a programme for pressure vessel monitoring has been prepared, including dosimetry. The dosimetry programme encompasses activation dosimeters (Cu, Nb, Co) and fission dosimeters ( 237 Np, 238 U) installed either inside the pressure vessel with the monitoring test-samples, or in a counting tube outside the pressure vessel. In the first place, a description of the method for neutronic calculation is given; such calculations use the codes ANISN and MERCURE 4 allowing assessment of the neutron spectrum seen by the detectors and the related reaction coefficient. This is followed by a description of the instrumentation. The initial dosimetry results available after the initial operating cycles concur with calculations [fr

A radiochromic film based on leucomalachite green for high-dose dosimetry applications

International Nuclear Information System (INIS)

Soliman, Y.S.; Basfar, A.A.; Msalam, R.I.

2014-01-01

A colorless polyvinyl butyral film (PVB) based on radiation-sensitive dye of leucomalachite green (LMG) was investigated as a high-dose dosimeter for gamma radiation processing applications in the dose range of 3–150 kGy. The useful applications for such dose range are food irradiation treatment, medical devices sterilization and polymer modification. Gamma irradiation of the film induces a significant intensity of green color, which can be characterized by a main absorption band at 627 nm and a small band at 425 nm. The variation in response of irradiated film stored in the dark and under laboratory light illumination was less than 3% during the first 6 days of storage. The response of film during irradiation was slightly influenced by relative humidity in the range of 12–76%; however, it was significantly affected by temperature in the range of 5–40 °C. The radiation chemical yield was reported to be 6.76 × 10 −6  mol/J at the absorbed dose of 30 kGy for the film containing 6.5% of LMG dye. The overall uncertainty associated with routine dose monitoring would be less than 6% at a 95% confidence level if the dosimeter was being corrected for irradiation conditions and being calibrated with reference standard dosimeter in the production facility. - Highlights: • Development of a radiochromic film based on leucomalachite green dye for radiation processing dosimetry. • The dosimeter useful dose range is 3–150 kGy. • The dosimeter was slightly influenced by humidity levels during irradiation over the range of 12–76%. • The films stored in the dark have a good shelf life with a good stable response after irradiation. • Overall uncertainty of the dosimeter was less than 4.3% at σ

Neutron dose and energy spectra measurements at Savannah River Plant

International Nuclear Information System (INIS)

Brackenbush, L.W.; Soldat, K.L.; Haggard, D.L.; Faust, L.G.; Tomeraasen, P.L.

1987-08-01

Because some workers have a high potential for significant neutron exposure, the Savannah River Plant (SRP) contracted with Pacific Northwest Laboratory (PNL) to verify the accuracy of neutron dosimetry at the plant. Energy spectrum and neutron dose measurements were made at the SRP calibrations laboratory and at several other locations. The energy spectra measurements were made using multisphere or Bonner sphere spectrometers, 3 He spectrometers, and NE-213 liquid scintillator spectrometers. Neutron dose equivalent determinations were made using these instruments and others specifically designed to determine dose equivalent, such as the tissue equivalent proportional counter (TEPC). Survey instruments, such as the Eberline PNR-4, and the thermoluminescent dosimeter (TLD)-albedo and track etch dosimeters (TEDs) were also used. The TEPC, subjectively judged to provide the most accurate estimation of true dose equivalent, was used as the reference for comparison with other devices. 29 refs., 43 figs., 13 tabs

Dosimeter charging and/or reading apparatus

International Nuclear Information System (INIS)

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

1980-01-01

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

Neutron radiography using neutron imaging plate

International Nuclear Information System (INIS)

Chankow, Nares; Wonglee, Sarinrat

2008-01-01

Full text: The aims of this research are to study properties of neutron imaging plate, to obtain a suitable condition for neutron radiography and to use the neutron imaging plate for testing of materials nondestructively. The experiments were carried out by using a neutron beam from the Thai Research Reactor TRR-1/M1 at a power of 1.2 MW. A BAS-ND 2040 FUJI neutron imaging plate and a MX125 Kodak X-ray film/Gadolinium neutron converter screen combination were tested for comparison. It was found that the photostimulated light (PSL) read out of the imaging plate was directly proportional to the exposure time. It was also found that radiography with neutron using the imaging plate was approximately 40 times faster than the conventional neutron radiography using x-ray film/Gd converter screen combination. The sensitivity of the imaging plate to gamma-rays was investigated by using gamma-rays from an 192 Ir and a 60 Co radiographic sources. The imaging plate was found to be 5-6 times less sensitive to gamma-rays than a FUJI BAS-MS 2040 gamma-ray imaging plate. Finally, some specimens were selected to be radiographed with neutrons using the imaging plate and the x-ray film/Gd converter screen combination in comparison to x-rays. Parts containing light elements could be clearly observed by the two neutron radiographic techniques. It could be concluded that the image quality from the neutron imaging plate was comparable to the conventional x-ray film/Gd converter screen combination but the exposure time could be approximately reduced by a factor of 40

Design and development of an in-line sputtering system and process development of thin film multilayer neutron supermirrors

Energy Technology Data Exchange (ETDEWEB)

Biswas, A.; Sampathkumar, R.; Kumar, Ajaya; Bhattacharyya, D.; Sahoo, N. K. [Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Lagoo, K. D.; Veerapur, R. D.; Padmanabhan, M.; Puri, R. K. [Division of Remote Handling and Robotics, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Bhattacharya, Debarati; Singh, Surendra; Basu, S. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2014-12-15

Neutron supermirrors and supermirror polarizers are thin film multilayer based devices which are used for reflecting and polarizing neutrons in various neutron based experiments. In the present communication, the in-house development of a 9 m long in-line dc sputtering system has been described which is suitable for deposition of neutron supermirrors on large size (1500 mm × 150 mm) substrates and in large numbers. The optimisation process of deposition of Co and Ti thin film, Co/Ti periodic multilayers, and a-periodic supermirrors have also been described. The system has been used to deposit thin film multilayer supermirror polarizers which show high reflectivity up to a reasonably large critical wavevector transfer of ∼0.06 Å{sup −1} (corresponding to m = 2.5, i.e., 2.5 times critical wavevector transfer of natural Ni). The computer code for designing these supermirrors has also been developed in-house.

The Efficiency of the BC-720 Scintillator in a High-Energy (20--800 MeV) Accelerator Neutron Field

Energy Technology Data Exchange (ETDEWEB)

Miles, Leslie H. [Univ. of Missouri, Columbia, MO (United States)

2005-12-01

High-energy neutron doses (>20 MeV) are of little importance to most radiation workers. However, space and flight crews, and people working around medical and scientific accelerators receive over half of their radiation dose from high-energy neutrons. Unfortunately, neutrons are difficult to measure, and no suitable dosimetry has yet been developed to measure this radiation. In this paper, basic high-energy neutron interactions, characteristics of high-energy neutron environments, present neutron dosimetry, and quantities used in neutron dosimetry are discussed before looking into the potential of the BC-720 scintillator to improve dosimetry. This research utilized 800 MeV protons impinging upon the WNR Facility spallation neutron source at Los Alamos National Laboratory. Time-of-flight methods and a U-238 Fission Chamber were used to aid evaluation of the efficiency of the BC-720. Results showed that the efficiency is finite over the 20–650 MeV energy region studied, although it decreases by a factor of ten between 40 and 100 MeV. This limits the use of this dosimeter to measure doses at sitespecific locations. It also encourages modifications to use this dosimeter for any unknown neutron field. As such, this dosimeter has the potential for a small, lightweight, real-time dose measurement, which could impact neutron dosimetry in all high-energy neutron environments.

Survey of neutrons inside the containment of a pressurized water reactor

International Nuclear Information System (INIS)

Hankins, D.E; Griffith, R.V.

1978-01-01

A neutron survey was made inside the containment of the Farley Nuclear Plant, Alabama Power and Light Company, Dothan, Alabama, in November 1977. The survey was made to determine the spectra of leakage neutrons and to evaluate the accuracy of albedo neutron dosimeters and a 9-in.-diameter sphere rem meter. The survey also covered variations in the neutron spectra, the ratio of gamma-to-neutron dose rates, and the thermal neutron component of the neutron dose

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-12-15

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

Electron trapping in neutron-irradiated very thin films of Al2O3

International Nuclear Information System (INIS)

Srivastava, P.C.; Bardhan, A.R.

1979-01-01

Oxide layers of thicknesses less than 100 A have been prepared by thermal-oxidation of a base metal electrode film of aluminium. These films were then neutron-irradiated from a laboratory Ra-Be source to a fluence of approximately 10 11 neutrons cm -2 and the sandwich structure, Al-Al 2 O 3 -Au, was completed by depositing a thin metal film of gold over the irradiated oxide layer. D.C. steady and transient flow through the sandwich structures have been studied. Results obtained in the experiments with irradiated sandwiches have been compared with unirradiated ones to show that traps are introduced because of the damage caused by the incident neutrons. Transient voltage measurement across the junction gives a trap density of approximately 10 18 cm -3 . A capture cross-section of the order 10 -28 cm 2 is estimated for the traps. It is found that the (identified) traps are uniformly distributed within an energy of 0.099 eV below the conduction band edge of aluminium oxide. The physical nature of the traps is discussed by comparing the capture cross-sections of the physically known trapping centres. The possibility of vacancies or F-centres acting as traps (for the identified ones) has been suggested. (author)

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

Reproducibility Test for Thermoluminescence Dosimeter (TLD) Using TLD Radpro

International Nuclear Information System (INIS)

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

2016-01-01

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

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

International Nuclear Information System (INIS)

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

2004-01-01

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

Personnel neutron dosimetry at Department of Energy facilities

International Nuclear Information System (INIS)

Brackenbush, L.W.; Endres, G.W.R.; Selby, J.M.; Vallario, E.J.

1980-08-01

This study assesses the state of personnel neutron dosimetry at DOE facilities. A survey of the personnel dosimetry systems in use at major DOE facilities was conducted, a literature search was made to determine recent advances in neutron dosimetry, and several dosimetry experts were interviewed. It was concluded that personnel neutron dosimeters do not meet current needs and that serious problems exist now and will increase in the future if neutron quality factors are increased and/or dose limits are lowered

Doped organic films for OLEDs probed with neutron reflectometry

International Nuclear Information System (INIS)

Smith, Arthur R. G.; Lo, Shih-Chun; Gentle, Ian R.

2009-01-01

Full text: Conjugated organic semiconductors form an exciting class of materials that can be used in a variety of cutting edge technologies including organic light-emitting diodes, solar cells and transistors. In all these technologies the thin film morphology and interfacial interactions are key areas for their operation. In order to optimise the materials and devices it is critical to understand the structural property relationships for the organic semiconductors by relating the 'molecular' structure to the film morphology and correlating these to the photophysical and device characteristics. Organic light emitting diodes (OLEO) have gained interest for their superior performance compared to current display technologies. Optimising the active emissive layer remains a challenge which can significantly affect the final performance of the device [1]. We have investigated the layering behaviour of small molecule co-evaporated films of deuterated 4,4'-bis(9-carbazolyl)-1, 1 '-biphenyl doped with tris-phenylpyridine iridium(llI) using neutron reflectometry The behaviour of doped emissive layers is dependent on the ratio between dopant and host material. The morphology and internal structure of such films have not yet been investigated, leading to questions about the phase separation and ordering of layers within the film.

A simultaneous electron energy and dosimeter calibration method for an electron beam irradiator

International Nuclear Information System (INIS)

Tanaka, R.; Sunaga, H.; Kojima, T.

1991-01-01

In radiation processing using electron accelerators, the reproducibility of absorbed dose in the product depends not only on the variation of beam current and conveyor speed, but also on variations of other accelerator parameters. This requires routine monitoring of the beam current and the scan width, and also requires periodical calibration of routine dosimeters usually in the shape of film, electron energy, and other radiation field parameters. The electron energy calibration is important especially for food processing. The dose calibration method using partial absorption calorimeters provides only information about absorbed dose. Measurement of average electron current density provides basic information about the radiation field formed by the beam scanning and scattering at the beam window, though it does not allow direct dose calibration. The total absorption calorimeter with a thick absorber allows dose and dosimeter calibration, if the depth profile of relative dose in a reference absorber is given experimentally. It also allows accurate calibration of the average electron energy at the surface of the calorimeter core, if electron fluence received by the calorimeter is measured at the same time. This means that both electron energy and dosimeters can be simultaneously calibrated by irradiation of a combined system including the calorimeter, the detector of the electron current density meter, and a thick reference absorber for depth profile measurement of relative dose. We have developed a simple and multifunctional system using the combined calibration method for 5 MeV electron beams. The paper describes a simultaneous calibration method for electron energy and film dosimeters, and describes the electron current density meter, the total absorption calorimeter, and the characteristics of this method. (author). 13 refs, 7 figs, 3 tabs

X-ray and neutron scattering from amorphous diamondlike carbon and hydrocarbon films

International Nuclear Information System (INIS)

Findeisen, E.

1994-10-01

In this report amorphous, diamondlike, carbon and hydrocarbon films are investigated by two different methods, namely, X-ray scattering and a combination of X-ray and neutron reflectivity. As specular reflectivity probes the scattering length density profile of a sample perpendicular to its surface, the combination of X-ray and neutron reflectivity reveals the nuclei density of both carbon and hydrogen separately. This allows to calculate the concentration of hydrogen in the films, which varies in the presented experiments between 0 and 36 atomic %. This method is a new and nondestructive technique to determine the concentration of hydrogen within an error of about ±1 at. % in samples with sharp interfaces. It is well suited for thin diamondlike carbon films. X-ray scattering is used to obtain structural information on the atomic scale, especially the average carbon-carbon distance and the average coordination number of the carbon atoms. As grazing incidence diffraction experiments were not successful, free-standing films are used for the scattering experiments with synchrotron light. However, the scattered intensity for large scattering vectors is, in spite of the intense primary beam, very weak, and therefore the accuracy of the obtained structural parameter is not sufficient to prove the diamondlike properties also on the atomic scale. (au) (10 tabs., 76 ills., 102 refs.)

Hydrogen Absorption in Metal Thin Films and Heterostructures Investigated in Situ with Neutron and X-ray Scattering

Directory of Open Access Journals (Sweden)

Sara J. Callori

2016-05-01

Full Text Available Due to hydrogen possessing a relatively large neutron scattering length, hydrogen absorption and desorption behaviors in metal thin films can straightforwardly be investigated by neutron reflectometry. However, to further elucidate the chemical structure of the hydrogen absorbing materials, complementary techniques such as high resolution X-ray reflectometry and diffraction remain important too. Examples of work on such systems include Nb- and Pd-based multilayers, where Nb and Pd both have strong affinity to hydrogen. W/Nb and Fe/Nb multilayers were measured in situ with unpolarized and polarized neutron reflectometry under hydrogen gas charging conditions. The gas-pressure/hydrogen-concentration dependence, the hydrogen-induced macroscopic film swelling as well as the increase in crystal lattice plane distances of the films were determined. Ferromagnetic-Co/Pd multilayers were studied with polarized neutron reflectometry and in situ ferromagnetic resonance measurements to understand the effect of hydrogen absorption on the magnetic properties of the system. This electronic effect enables a novel approach for hydrogen sensing using a magnetic readout scheme.

Design and operation of a 2-D thin-film semiconductor neutron detector array for use as a beamport monitor

International Nuclear Information System (INIS)

Unruh, Troy C.; Bellinger, Steven L.; Huddleston, David E.; McNeil, Walter J.; Patterson, Eric; Sobering, Tim J.; McGregor, Douglas S.

2009-01-01

Silicon-based diodes coated with a thin film of neutron reactive materials have been shown to produce excellent low-efficiency neutron detectors. This work employs the same technology, but groups 25 equally sized and spaced diodes on a single 29 mm by 29 mm substrate. A 5x5 array was fabricated and coated with a thin film of 6 LiF for use as a low-efficiency neutron beam monitor. The 5x5 neutron detector array is coupled to an array of amplifiers, allowing the response to be interpreted using a LabVIEW FPGA. The 5x5 array has been characterized in a diffracted neutron beam. This work is a part of on-going research to develop various designs of high- and low-efficiency semiconductor neutron detectors.

On the characteristics of color film dosimeter

International Nuclear Information System (INIS)

Ohnishi, Tokuhiro; Hiraoka, Eiichi; Furuta, Junichiro

1978-01-01

Practical applicability of dosimetric color films available as Nitto Radocolor in commerce have been examined. The characteristics for dosimetry were studied using gamma-rays from Co-60 sources. The films can be stored without any deterioration unless they are exposed directly to sunlight or ultraviolet light. The dosage is easily estimated by comparing the irradiation-changed color of the film with a given standardized color chart. The dosage can be determined within an accuracy of 40% by the use of the printed color chart (Color Standard) supplied Nitto Co. and within an accuracy of 20% by the use of a color chart with color films which has been prepared by the present study. (auth.)

Ordering phenomena in FeCo-films and Fe/Cr-multilayers: an X-ray and neutron scattering study

Energy Technology Data Exchange (ETDEWEB)

Nickel, B.

2001-07-01

The following topics are covered: critical phenomena in thin films, critical adsorption, finite size scaling, FeCo Ising model, kinematical scattering theory for thin films, FeCo thin films, growth and characterisation of single crystal FeCo thin films, X-ray study of ordering in FeCo films, antiferromagnetic coupling in Fe/Cr multilayers, neutron scattering on Fe/Cr multilayers (WL)

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

International Nuclear Information System (INIS)

Yordanov, N.D.; Gancheva, V.

1999-01-01

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

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

Film badge personnel monitoring and dose distribution of industrial and medical workers in the country (1994-1998)

International Nuclear Information System (INIS)

Mittal, Hariom; Pandey, R.L.; Massand, O.P.

2001-03-01

Personnel Monitoring Section, Bhabha Atomic Research Centre, Mumbai, is entrusted with the responsibility of providing a countrywide personnel monitoring to radiation workers using extemal radiation like X, beta, gamma and neutron. As per Radiation Protection Rules (RPR) of 1971 promulgated by the competent authority the personnel monitoring service is mandatory for all the workers working with radiation. The radiation exposures received by them should be within the limits stipulated by AERB. Nearly 43,000 radiation workers in about 3000 DAE and non DAE institutions using radiation and radioisotopes are monitored, using both the Film Badges and the Thermoluminescent dosimeters. This report presents various aspects of film dosimetry which was introduced more than four decades ago in the country and also analysis of doses received by the radiation workers in the five year block 1994-1998 covered by film badge service. (author)

Lithium Blanket Module dosimetry measurements at the LOTUS 14-MeV neutron source facility

International Nuclear Information System (INIS)

Tsang, F.Y.; Leo, W.R.; Sahraoui, C.; Wuthrich, S.; Harker, Y.D.

1986-01-01

This paper describes the measurements and results of the dosimeter material reaction rates inside the Lithium Blanket Module (LBM) after irradiation by the LOTUS 14-MeV neutron source at the Ecole Polytechnique Federale de Lausanne. The measurement program has been designed to utilize sets of passive dosimeter materials in the form of foils and wires. The dosimetry materials reaction thresholds and interaction response ranges chosen for this series of measurements encompass the entire neutron spectra along the full length of the LBM fuel rods

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)

Aerated Systems of the Type RH-RCl-Ethanol-Thymolsulphonphthalein Stable Low-Level Chemical Dosimeters

Energy Technology Data Exchange (ETDEWEB)

Dvornik, I.; Zec, U.; Anic, A.; Ranogajec, F. [Institute Ruder Boskovic, Zagreb, Yugoslavia (Croatia)

1967-03-15

The characteristic of dosimeters described in this paper is concerned with the very sensitive colorimetric method of dose evaluation giving a fair sensitivity with low G(HC1). In addition, the systems are thermally stable and simple to manufacture. With photocolorimetric or spectrophotometric evaluation of about 100 rad the dosimetric: error can be as low as 1 rad, or lower. The examined technique of visual colorimetric evaluation at the same dose level gives the combined error of 10-20 rad, and up to {+-} 5 or 10% at 500 rad. Owing to the practically unlimited shelf life of dosimeters and visual colorimeters, and to the very low production costs of both devices, such chemical dosimeters could be of special interest for massive use as personal gamma dosimeters for wide populations, or as dosimeters for gamma and fast neutron dosimetric topography of nuclear accidents. With tetrachloroethylene and iso-octane G(HC1) has been found constant (8.4) for temperatures of between -10 and +35 Degree-Sign C and for dose-rates of between 80 and 80 000 rad/h. The upper dose limit of colorimetric evaluation is about 2000 rad. With other components G(HC1) can be lower and the range extends to higher doses. The colorimetric properties of the systems RH-ethanol-thymolsulphonphthalein, as well as some of the most interesting features of the production procedure, are described. The radiation chemical aspects are discussed briefly. (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)

Chemical methods for the use of niobium from pressure vessel cladding as a fast neutron dosimeter

International Nuclear Information System (INIS)

Karnani, Hari

1986-08-01

the steel samples from the cladding of a pressure vessel of an operating nuclear power reactor were obtained by scraping. The cladding material of the pressure vessel contained about 0.5 % niobium. It was desired to use the niobium as a dosimeter for estimating fast fluences at the pressure vessel. The weak radiation from the reaction product 93m Nb cannot be measured in the presence of other elements and interfering activities. A method was developed to separate niobium from other metals present; the concentration and yield of niobium were determined spectrophotometrically. The irradiated niobium was electrodeposited from aqueous solutions on copper discs. The amount of the deposited niobium was determined by a radiochemical method which makes use of its own radioactivity - measured with a liquid scintillation counter - and the known starting mass of niobium. It was possible to determine the deposited niobium masses (5 to 200 microgram) with a desired degree of accuracy. The absolute emission rate of X-rays could then be measured without any self-absorption or interference from other activities. The mass of niobium on each preparate and its X-ray emission rate, later on, were used as basic experimental data for the estimation of last neutron doses at the pressure vessel

Remeasurement of early Harwell personnel film dosimeters

International Nuclear Information System (INIS)

Smith, J.W.; McGuinness, E.A.

1981-05-01

The A.E.A. epidemiological study depends for its radiation dose data on records of film badge doses which have been stored continuously since 1947. The records were originally kept to assist in the control of radiation hazard to the individual and for that purpose doses below the measurement threshold were unimportant. The epidemiological study could consider these doses to be either zero or equal to the measurement threshold, but both assumptions risk introducing a bias. Samples of old films worn in 1955 and 1960 were therefore remeasured using the present-day lower threshold of 0.005 rems to aid the choice of the most correct estimate. It was found that there had been little change in the blackening on the films or in the assessed radiation dose for 238 films above the original threshold of 0.05 rems, confirming that remeasurement was possible. The 2426 films previously recorded as ''<0.05 rems'' were found on remeasurement to give an average dose of 0.009 rems. A similar epidemiological study of radiation workers at Hanford took threshold doses as equal to zero and considered only positive measured doses. The errors possible with this approach are discussed. (author)

Study on boron-film thermal neutron converter prepared by pulsed laser deposition

International Nuclear Information System (INIS)

Song Zifeng; Ye Shuzhen; Chen Ziyu; Song Liao; Shen Ji

2011-01-01

The boron film converter used in the position-sensitive thermal neutron detector is discussed and the method of preparing this converter layer via Pulsed Laser Deposition (PLD) is introduced. The morphology and the composition were studied by Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). Both boron and boride existed on the layer surface. It was shown that the energy intensity of laser beam and the substrate temperature both had an important influence on the surface morphology of the film.

Study on boron-film thermal neutron converter prepared by pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Song Zifeng; Ye Shuzhen; Chen Ziyu; Song Liao [Department of Modern Physics, University of Science and Technology of China, Anhui Hefei 230026 (China); Shen Ji, E-mail: shenji@ustc.edu.c [Department of Modern Physics, University of Science and Technology of China, Anhui Hefei 230026 (China)

2011-02-15

The boron film converter used in the position-sensitive thermal neutron detector is discussed and the method of preparing this converter layer via Pulsed Laser Deposition (PLD) is introduced. The morphology and the composition were studied by Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). Both boron and boride existed on the layer surface. It was shown that the energy intensity of laser beam and the substrate temperature both had an important influence on the surface morphology of the film.

Determination of oxide film thickness on aluminium using 14-MeV neutron activation and BET method

International Nuclear Information System (INIS)

Foerster, H.

1983-01-01

A new method is described for the determination of the mean film thickness of aluminium oxides by 14-MeV neutron activation analysis of the oxygen and by BET measurement of the surface area. The mean film thickness obtained is independent of the surface roughness. Stable oxide films consisting of only a few atomic layers of oxygen are detected on aluminium. (author)

Dyed grafted films for large-dose radiation dosimetry

Energy Technology Data Exchange (ETDEWEB)

Abdel Rehim, F; El-Sawy, N M; Abdel-Fattah, A A [National Centre for Radiation Research and Technology, Cairo (Egypt)

1993-07-01

By radiation-induced polymerization of acrylic acid onto poly(ethylene-tetrafluoroethylene) (ET) copolymer film and reacting the resulted grafted film with both Rhodamine B (RB) and Malachite Green (MG), new dosimeter films have been developed for high-dose gamma radiation applications in the range of absorbed doses from 10 to 180 kGy. The radiation-induced color bleaching has been analysed with visible spectrophotometry, either at the maximum of the absorption band peaking at 559 nm (for ETRB) or that peaking at 627 nm (for ETMG). The effects of different conditions of absorbed dose rate, temperature and relative humidity during irradiation and post-irradiation storage on dosimeter performance are discussed. (author).

A real time scintillating fiber Time of Flight spectrometer for LINAC photoproduced neutrons

Science.gov (United States)

Maspero, M.; Berra, A.; Conti, V.; Giannini, G.; Ostinelli, A.; Prest, M.; Vallazza, E.

2015-03-01

The use of high-energy (> 8 MeV) LINear ACcelerators (LINACs) for medical cancer treatments causes the photoproduction of secondary neutrons, whose unwanted dose to the patient has to be calculated. The characterization of the neutron spectra is necessary to allow the dosimetric evaluation of the neutron beam contamination. The neutron spectrum in a hospital environment is usually measured with integrating detectors such as bubble dosimeters, Thermo Luminescent Dosimeters (TLDs) or Bonner Spheres, which integrate the information over a time interval and an energy one. This paper presents the development of a neutron spectrometer based on the Time of Flight (ToF) technique in order to perform a real time characterization of the neutron contamination. The detector measures the neutron spectrum exploiting the fact that the LINAC beams are pulsed and arranged in bunches with a rate of 100-300 Hz depending on the beam type and energy. The detector consists of boron loaded scintillating fibers readout by a MultiAnode PhotoMultiplier Tube (MAPMT). A detailed description of the detector and the acquisition system together with the results in terms of ToF spectra and number of neutrons with a Varian Clinac iX are presented.

CMOS-Based Neutron Spectroscopic Dosimeter (CNSD), Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Monitoring space radiation and the dose received by astronauts is important, especially for future long-duration missions. Neutrons contribute a significant...

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

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.

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

Correlation between locally deformed structure and oxide film properties in austenitic stainless steel irradiated with neutrons

Energy Technology Data Exchange (ETDEWEB)

Chimi, Yasuhiro, E-mail: chimi.yasuhiro@jaea.go.jp [Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Kitsunai, Yuji [Nippon Nuclear Fuel Development, 2163 Narita-cho, Oarai-machi, Higashi-ibaraki-gun, Ibaraki 311-1313 (Japan); Kasahara, Shigeki [Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Chatani, Kazuhiro; Koshiishi, Masato [Nippon Nuclear Fuel Development, 2163 Narita-cho, Oarai-machi, Higashi-ibaraki-gun, Ibaraki 311-1313 (Japan); Nishiyama, Yutaka [Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan)

2016-07-15

To elucidate the mechanism of irradiation-assisted stress corrosion cracking (IASCC) in high-temperature water for neutron-irradiated austenitic stainless steels (SSs), the locally deformed structures, the oxide films formed on the deformed areas, and their correlation were investigated. Tensile specimens made of irradiated 316L SSs were strained 0.1%–2% at room temperature or at 563 K, and the surface structures and crystal misorientation among grains were evaluated. The strained specimens were immersed in high-temperature water, and the microstructures of the oxide films on the locally deformed areas were observed. The appearance of visible step structures on the specimens' surface depended on the neutron dose and the applied strain. The surface oxides were observed to be prone to increase in thickness around grain boundaries (GBs) with increasing neutron dose and increasing local strain at the GBs. No penetrative oxidation was observed along GBs or along surface steps. - Highlights: • Visible step structures depend on the neutron dose and the applied strain. • Local strain at grain boundaries was accumulated with the neutron dose. • Oxide thickness increases with neutron dose and local strain at grain boundaries. • No penetrative oxidation was observed along grain boundaries or surface steps.

Operation of Personal Electronic Dosimeters at NRCN

International Nuclear Information System (INIS)

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

2004-01-01

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

Application of the alanine detector to gamma-ray, X-ray and fast neutron dosimetry

International Nuclear Information System (INIS)

Waligorski, M.P.R.; Hansen, J.W.; Byrski, E.

1987-01-01

A dosimeter based on alanine has been developed at the INP in Krakow and at Risoe National Laboratory. Due to its near tissue-equivalence and stability of signal, measured using ESR spectrometry at room temperature, this free-radical amino-acid dosimetric system is particularly suitable for measuring X-ray, gamma-ray and fast neutron doses in the range 10-10 5 Gy. The relative effectiveness (with respect to 60 Co γ-rays) of the alanine dosimeter to 250 kVp X-rays and to cyclotron-produced fast neutrons (mean neutron energy 5.6 MeV) is measured to be 0.76± 0.06 and 0.60±0.05, respectively. The suitability of the alanine dosimeter for intercomparison gamma-ray dosimetry is also shown. The estimated absolute difference between 60 Co dosimetry at Risoe National Laboratory and at the Centre of Oncology in Krakow is about 5%, somewhat more than the experimental uncertainty. These results are based on ESR measurements performed in Krakow on about 25% of the exposed detectors. 28 refs., 2 figs., 3 tabs. (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)

To the attention of all dosimeter users

CERN Multimedia

2005-01-01

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

To the attention of all dosimeter users

CERN Multimedia

Dosimetry Service

2005-01-01

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

To the attention of all dosimeter users

CERN Multimedia

Dosimetry Service

2006-01-01

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

Development of neutron fluence measurement and evaluation technology for the test materials in the capsule

Energy Technology Data Exchange (ETDEWEB)

Hong, U.; Choi, S. H.; Kang, H. D. [Kyungsan University, Kyungsan (Korea)

2000-03-01

The four kinds of the fluence monitor considered by self-shielding are design and fabricated for evaluation of neutron irradiation fluence. They are equipped with dosimeters consisting of Ni, Fe and Ti wires and so forth. The nuclear reaction rate is obtained by measurement on dosimeter using the spectroscopic analysis of induced {gamma}-ray. We established the nuetron fluence evaluating technology that is based on the measurement of the reaction rate considering reactor's irradiation history, burn-out, self-shielding in fluence monitor, and the influence of impurity in dosimeter. The distribution of high energy neutron flux on the vertical axis of the capsule shows fifth order polynomial equation and is good agree with theoretical value in the error range of 30% by MCNP/4A code. 22 refs., 50 figs., 27 tabs. (Author)

Cell-phone interference with pocket dosimeters

International Nuclear Information System (INIS)

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

2005-01-01

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

Cell-phone interference with pocket dosimeters

Energy Technology Data Exchange (ETDEWEB)

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

2005-05-07

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

Flame-sintered ceramic exoelectron dosimeter samples

International Nuclear Information System (INIS)

Petel, M.; Holzapfel, G.

1979-01-01

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

U and Th thin film neutron dosimetry for fission-track dating: application to the age standard Moldavite

International Nuclear Information System (INIS)

Iunes, P.J.; Bigazzi, G.; Hadler Neto, J.C.; Laurenzi, M.A.; Balestrieri, M.L.; Norelli, P.; Osorio Araya, A.M.; Guedes, S.; Tello S, C.A.; Paulo, S.R.; Moreira, P.A.F.P.; Palissari, R.; Curvo, E.A.C.

2005-01-01

Neutron dosimetry based on U and Th thin films was used for fission-track dating of the age standard Moldavite, the central European tektite, from the Middle Miocene deposit of Jankov (southern Bohemia, Czech Republic). Our fission-track age (13.98+/-0.58Ma) agrees with a recent 40 Ar/ 39 Ar age, 14.34+/-0.04Ma, based on several determinations on Moldavites from different sediments, including the Jankov deposit. This result indicates that the U and Th thin film neutron dosimetry represents a reliable alternative for an absolute approach in fission-track dating

Neutron image intensifier tubes

International Nuclear Information System (INIS)

Verat, M.; Rougeot, H.; Driard, B.

1983-01-01

The most frequently used techniques in neutron radiography employ a neutron converter consisting of either a scintillator or a thin metal sheet. The radiation created by the neutrons exposes a photographic film that is in contact with the converter: in the direct method, the film is exposed during the time that the object is irradiated with neutrons; in the transfer method, the film is exposed after the irradiation of the object with neutrons. In industrial non-destructive testing, when many identical objects have to be checked, these techniques have several disadvantages. Non-destructive testing systems without these disadvantages can be constructed around neutron-image intensifier tubes. A description and the operating characteristics of neutron-image intensifier tubes are given. (Auth.)

DEPRON dosimeter for ``Lomonosov'' satellite

Science.gov (United States)

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

appearance of the instrument DEPRON (Dosimeter of Electrons, PROtons and Neutrons) was determined. DEPRON is intended for registration of the absorbed doses and linear energy transfer spectra for high-energy electrons, protons and nuclei of space radiation, as well as registration of thermal and slow neutrons. The experiment based on DEPRON instrument is aimed at the studies of the distribution of space radiation dose rate at high latitude paths in order to study the flight paths of perspective manned spacecraft. Present work provides a brief description of the DEPRON instrument, its calibration results and the structure of the output data.

Potentialities and practical limitations of absolute neutron dosimetry using thin films of uranium and thorium applied to the fission track dating

CERN Document Server

Bigazzi, G; Hadler-Neto, J C; Iunes, P J; Paulo, S R; Oddone, M; Osorio, A M A; Zúñiga, A G

1999-01-01

Neutron dosimetry using natural uranium and thorium thin films makes possible that mineral dating by the fission-track method can be accomplished, even when poor thermalized neutron facilities are employed. In this case, the contributions of the fissions of sup 2 sup 3 sup 5 U, sup 2 sup 3 sup 8 U and sup 2 sup 3 sup 2 Th induced by thermal, epithermal and fast neutrons to the population of tracks produced during irradiation are quantified through the combined use of natural uranium and thorium films. If the Th/U ratio of the sample is known, only one irradiation (where the sample and the films of uranium and thorium are present) is necessary to perform the dating. However, if that ratio is unknown, it can be determined through another irradiation where the mineral to be dated and both films are placed inside a cadmium box. Problems related with film manufacturing and calibration are discussed. Special attention is given to the utilization of thin films having very low uranium content. The problems faced sugg...

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.

Separation and correlation of structural and magnetic roughness in a Ni thin film by polarized off-specular neutron reflectometry.

Science.gov (United States)

Singh, Surendra; Basu, Saibal

2009-02-04

Diffuse (off-specular) neutron and x-ray reflectometry has been used extensively for the determination of interface morphology in solids and liquids. For neutrons, a novel possibility is off-specular reflectometry with polarized neutrons to determine the morphology of a magnetic interface. There have been few such attempts due to the lower brilliance of neutron sources, though magnetic interaction of neutrons with atomic magnetic moments is much easier to comprehend and easily tractable theoretically. We have obtained a simple and physically meaningful expression, under the Born approximation, for analyzing polarized diffuse (off-specular) neutron reflectivity (PDNR) data. For the first time PDNR data from a Ni film have been analyzed and separate chemical and magnetic morphologies have been quantified. Also specular polarized neutron reflectivity measurements have been carried out to measure the magnetic moment density profile of the Ni film. The fit to PDNR data results in a longer correlation length for in-plane magnetic roughness than for chemical (structural) roughness. The magnetic interface is smoother than the chemical interface.

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

Improved analytical formulas for x-ray and neutron reflection from surface films

International Nuclear Information System (INIS)

Zhou, X.; Chen, S.; Felcher, G.P.

1992-01-01

A general and exact expression for x-ray and neutron reflectance and transmittance is given in terms of an integral of the real-space scattering-length-density profile fluctuation of the film, with respect to an arbitrary constant reference density level, over the wave function inside the film. Various special cases and approximations are then derived from this exact form by suitable approximations of the wave function. In particular, two practical approximate formulas are derived which are improvement over the corresponding distorted-wave Born approximations. One is for an arbitrary film deposited on a known substrate and the other for a free liquid surface. Numerical results are used to illustrate the accuracy of these formulas

Do you know DIS? a novel passive individual dosimeterd. Direct Ion Storage dosimeter DIS-1 officially approved in Switzerland

International Nuclear Information System (INIS)

Fiechtner, A.; Wernli, C.

2001-01-01

For individual monitoring film and TLD are the most often used types of dosimeters. On a smaller scale phosphate glasses and detectors based on optically stimulated luminescence (OSL) are also in use. As a new addition to the list of available personnel dosimeters the direct ion storage (DIS) system became legally approved for the first time in Switzerland. At the Paul Scherrer Institute (PSI) the RADOS dosimetry system DIS-1 is in official use since beginning of 2001. (orig.) [de

Radiation detectors for personnel monitoring - current developments and future trends

International Nuclear Information System (INIS)

Kannan, S.

2003-01-01

The radiation detectors for personnel monitoring range from the conventional passive dosimeters like the film badge and the TLD, to sophisticated active dosimeters for integrated gamma, beta and neutron dose measurement. With the availability of high accuracy active dosimeters, the process of personnel monitoring, acceptability among radiation workers, record keeping and dose control have become more simplified. However the high level of sophistication in the active dosimeter has its own inevitable price tag and the new breed of active dosimeters are prohibitively costly. The silver lining, in the otherwise dark cost scenario of these dosimeters is the potential for cost reduction at least in some of the dosimeters in the near future

A novel method for alpha dosimetry using peeled-off Gafchromic EBT3 films

Energy Technology Data Exchange (ETDEWEB)

Lee, Kwang-Ho; Kim, Eun-Hee [Seoul National University, Seoul (Korea, Republic of)

2016-10-15

One can estimate dose imposed to film by measuring the optical density of film. EBT3 film has been used in dose measurement for photon, proton, and electron beams but not for alpha particles. Both sides of diacetylene monomer layer are covered with 100 μm-thick polyester coating layers, through which alpha particles even at several MeV cannot penetrate. A recent study demonstrated the use of EBT3 film in alpha dosimetry by peeling off one side of polyester coating layer. Their study did not inform the reliability of measurement using the peeled-off films. In this study, we evaluated the feasibility of EBT3 film as a substitute for conventional alpha dosimeters and checked the uncertainty of dose measurements obtained with peeled-off EBT3 films. We also applied this film dosimeter to measuring of the fluence distribution at cell targets in a culture dish set in the alpha irradiation chamber of the Radiation Bioengineering Laboratory (RadBio Lab) at Seoul National University (SNU). In this work, we confirmed the feasibility of using Gafchromic EBT3 films for alpha dosimetry. The peeled-off EBT3 films can make a convenient alpha dosimeter by carrying an uncertainty less than 9 %.

Radiation dose measurements of the insertion devices using radiachromic film dosimeters

International Nuclear Information System (INIS)

Alderman, J.; Semones, E.; Job, P. K.

2004-01-01

The Advanced Photon Source (APS) uses Nd-Fe-B permanent magnets in the insertion devices to produce x-rays for scientific research [1,2]. Earlier investigations have exhibited varying degrees of demagnetization of these magnets [3] due to irradiation from electron beams [4,5,6], 60 Co γ-rays [5], and high-energy neutrons [7,8]. Radiation-induced demagnetization has been observed in the APS insertion devices [9] and was first measured in December of 2001. Partial demagnetization has also been observed in insertion devices at the European Synchrotron Radiation Facility (ESRF) [4,6], where Nd-Fe-B permanent magnets are also used. Growing concern for the lifetime of APS insertion devices, as well as the permanent magnets that will be used in next-generation, high-power light sources, like the FEL [10,11], resulted from the partial demagnetization observations made at both facilities. This concern in relation to radiation-induced demagnetization spurred a long-term project to measure and analyze the absorbed doses received by the APS insertion devices. The project required a reliable photon high-dose dosimetry technique capable of measuring absorbed doses greater than 10 6 rad, which was not readily available at the APS. Through a collaboration with the National Institute of Standards and Technology (NIST), one such technique using radiachromic films was considered, tested, and calibrated at the APS. This consequently led to the implementation of radiachromic film dosimetry for measuring the absorbed doses received by the insertion devices for each of the APS runs

Application of Monte Carlo codes to neutron dosimetry

International Nuclear Information System (INIS)

Prevo, C.T.

1982-01-01

In neutron dosimetry, calculations enable one to predict the response of a proposed dosimeter before effort is expended to design and fabricate the neutron instrument or dosimeter. The nature of these calculations requires the use of computer programs that implement mathematical models representing the transport of radiation through attenuating media. Numerical, and in some cases analytical, solutions of these models can be obtained by one of several calculational techniques. All of these techniques are either approximate solutions to the well-known Boltzmann equation or are based on kernels obtained from solutions to the equation. The Boltzmann equation is a precise mathematical description of neutron behavior in terms of position, energy, direction, and time. The solution of the transport equation represents the average value of the particle flux density. Integral forms of the transport equation are generally regarded as the formal basis for the Monte Carlo method, the results of which can in principle be made to approach the exact solution. This paper focuses on the Monte Carlo technique

Calibration of neutrons monitors with moderators and application in the calibration factors of albedo dosemeters

International Nuclear Information System (INIS)

Schuch, L.A.

1978-11-01

The calibration factors and the reproducibility of an Albedo Dosimeter designed for personal neutron monitoring were determined. These factor were obtained simulating the dosimeter reading and the equivalent dose in the locality by a convenient combination of responses of the Bonner Sphere Spectrometer. The results obtained in the simulation were verified experimentally for different spectra employing the Am-Be, bare 252 Cf source and 253 Cf source with graphite sields of varying thickness. Different standards were used in the procedures necessary for the determination of the calibration factors. An Am-Be neutron source, standardized by the activation of a manganese sulphate bath was used as a primary standard. As a secondary standard, for the measurement of the neutron fluence, a De Pangher Long Counter was used and the scattering effects were determined using the shadow cone method. The other monitors such as the Rem-Counter and the Bonner Sphere Spectrometer were also calibrated with reference to the secondary standard with a view to comparing the results obtained with those furnished by the Albedo Dosimeter. (Author) [pt

Evaluation of personal dosimeters

International Nuclear Information System (INIS)

Correa, C. A.

2007-01-01

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

Improved sample holders for the PMMA dosimeters

International Nuclear Information System (INIS)

Kobayashi, Toshikazu; Sone, Koji; Iso, Katsuaki

1994-01-01

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

The dielectric track and thermoluminescent detectors applied to neutron dosimetry in personnel monitoring

International Nuclear Information System (INIS)

Mebhah, D.

1984-03-01

The personnal dosimeter for neutron based on the detection of fission fragments from 237 Np and 232 Th by a polycarbonate 10 gm, and lithium fluorite 6 LIF/ 7 LIF, allow to cover an energy spectrum from 0.05 eV to 14 MeV with a easy neutron gamma discrimination. In criticality dosimetry, the energy spectrum of the incident neutrons can be defined by two components: the fast component by E b exp(-ae) with E between 0.1 and 14 MeV, a and b determined by a combination of 237 Np and 232 Th track detector responses, and the epithermal component in 1/E, the thermal component having a minor contribution to the total equivalent dose. We took into account the body influence on the detectors response by introducing effective cross section. The equivalent dose obtained by this dosimeter is 20% overestimated in low doses dosimetry. The interpretation of the detectors responses is based on the definition of a factor and a calibration parameter for each zone in which the spectrum is constant. The knowledge of this parameter for individual dosimeters allows to account for the variations of the conditions of calibration

The intelligence of dosimeter for ionization radiation

International Nuclear Information System (INIS)

He Jinglun

1992-01-01

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

ESR-dosimetry in thermal and epithermal neutron fields for application in boron neutron capture therapy

Energy Technology Data Exchange (ETDEWEB)

Schmitz, Tobias

2016-01-22

Dosimetry is essential for every form of radiotherapy. In Boron Neutron Capture Therapy (BNCT) mixed neutron and gamma fields have to be considered. Dose is deposited in different neutron interactions with elements in the penetrated tissue and by gamma particles, which are always part of a neutron field. The therapeutic dose in BNCT is deposited by densely ionising particles, originating from the fragmentation of the isotope boron-10 after capture of a thermal neutron. Despite being investigated for decades, dosimetry in neutron beams or fields for BNCT remains complex, due to the variety in type and energy of the secondary particles. Today usually ionisation chambers combined with metal foils are used. The applied techniques require extensive effort and are time consuming, while the resulting uncertainties remain high. Consequently, the investigation of more effective techniques or alternative dosimeters is an important field of research. In this work the possibilities of ESR-dosimeters in those fields have been investigated. Certain materials, such as alanine, generate stable radicals upon irradiation. Using Electron Spin Resonance (ESR) spectrometry the amount of radicals, which is proportional to absorbed dose, can be quantified. Different ESR detector materials have been irradiated in the thermal neutron field of the research reactor TRIGA research reactor in Mainz, Germany, with five setups, generating different secondary particle spectra. Further irradiations have been conducted in two epithermal neutron beams. The detector response, however, strongly depends on the dose depositing particle type and energy. It is hence necessary to accompany measurements by computational modelling and simulation. In this work the Monte Carlo code FLUKA was used to calculate absorbed doses and dose components. The relative effectiveness (RE), linking absorbed dose and detector response, has been calculated using amorphous track models. For the simulation, detailed models of

Citizen's dosimeter

Energy Technology Data Exchange (ETDEWEB)

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

2008-09-02

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

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

Reference radiation fields - Simulated workplace neutron fields - Part 2: Calibration fundamentals related to the basic quantities

International Nuclear Information System (INIS)

2008-01-01

ISO 8529-1, ISO 8529-2 and ISO 8529-3, deal with the production, characterization and use of neutron fields for the calibration of personal dosimeters and area survey meters. These International Standards describe reference radiations with neutron energy spectra that are well defined and well suited for use in the calibration laboratory. However, the neutron spectra commonly encountered in routine radiation protection situations are, in many cases, quite different from those produced by the sources specified in the International Standards. Since personal neutron dosimeters, and to a lesser extent survey meters, are generally quite energy dependent in their dose equivalent response, it might not be possible to achieve an appropriate calibration for a device that is used in a workplace where the neutron energy spectrum and angular distribution differ significantly from those of the reference radiation used for calibration. ISO 8529-1 describes four radionuclide based neutron reference radiations in detail. This part of ISO 12789 includes the specification of neutron reference radiations that were developed to closely resemble radiation that is encountered in practice

Influence of environmental factors on some high dose dosimeter responses in Yazd Radiation Processing Center

International Nuclear Information System (INIS)

Ziaie, F.; Tahami, S.M.; Zareshahi, H.; Lanjanian, H.; Durrani, S.A.

2008-01-01

In this paper attempt has been made to study the influence of temperature and UV light (exist in laboratory due to the fluorescent light or diffused sunlight) on some high dose dosimetry responses that are being used in Yazd Radiation Processing Center (YRPC). The CTA, FWT and B3 film dosimeters were used for this investigation. The correction of the read response of the dosimeters to the real absorbed dose values is very important especially while we need to measure the precise dose values in the medical devices and in foodstuff materials. Yazd city is near to the desert, and so temperature and UV light due to the sun are very different in compare to other cities. Therefore, we tried to investigate the temperature and UV light effects on the dosimeter response in different doses and obtain its variation as a function of temperature (up to ∼60 0 C) and exposure time (up to ∼1 year), respectively

Investigation of Workplace-like Calibration Fields via a Deuterium-Tritium (D-T) Neutron Generator.

Science.gov (United States)

Mozhayev, Andrey V; Piper, Roman K; Rathbone, Bruce A; McDonald, Joseph C

2017-04-01

Radiation survey meters and personal dosimeters are typically calibrated in reference neutron fields based on conventional radionuclide sources, such as americium-beryllium (Am-Be) or californium-252 (Cf), either unmodified or heavy-water moderated. However, these calibration neutron fields differ significantly from the workplace fields in which most of these survey meters and dosimeters are being used. Although some detectors are designed to yield an approximately dose-equivalent response over a particular neutron energy range, the response of other detectors is highly dependent upon neutron energy. This, in turn, can result in significant over- or underestimation of the intensity of neutron radiation and/or personal dose equivalent determined in the work environment. The use of simulated workplace neutron calibration fields that more closely match those present at the workplace could improve the accuracy of worker, and workplace, neutron dose assessment. This work provides an overview of the neutron fields found around nuclear power reactors and interim spent fuel storage installations based on available data. The feasibility of producing workplace-like calibration fields in an existing calibration facility has been investigated via Monte Carlo simulations. Several moderating assembly configurations, paired with a neutron generator using the deuterium tritium (D-T) fusion reaction, were explored.

Dosimetry auditing procedure with alanine dosimeters for light ion beam therapy

International Nuclear Information System (INIS)

Ableitinger, Alexander; Vatnitsky, Stanislav; Herrmann, Rochus; Bassler, Niels; Palmans, Hugo; Sharpe, Peter; Ecker, Swantje; Chaudhri, Naved; Jäkel, Oliver; Georg, Dietmar

2013-01-01

Background and purpose: In the next few years the number of facilities providing ion beam therapy with scanning beams will increase. An auditing process based on an end-to-end test (including CT imaging, planning and dose delivery) could help new ion therapy centres to validate their entire logistic chain of radiation delivery. An end-to-end procedure was designed and tested in both scanned proton and carbon ion beams, which may also serve as a dosimetric credentialing procedure for clinical trials in the future. The developed procedure is focused only on physical dose delivery and the validation of the biological dose is out of scope of the current work. Materials and methods: The audit procedure was based on a homogeneous phantom that mimics the dimension of a head (20 × 20 × 21 cm 3 ). The phantom can be loaded either with an ionisation chamber or 20 alanine dosimeters plus 2 radiochromic EBT films. Dose verification aimed at measuring a dose of 10 Gy homogeneously delivered to a virtual-target volume of 8 × 8 × 12 cm 3 . In order to interpret the readout of the irradiated alanine dosimeters additional Monte Carlo simulations were performed to calculate the energy dependent detector response of the particle fluence in the alanine detector. A pilot run was performed with protons and carbon ions at the Heidelberg Ion Therapy facility (HIT). Results: The mean difference of the absolute physical dose measured with the alanine dosimeters compared with the expected dose from the treatment planning system was −2.4 ± 0.9% (1σ) for protons and −2.2 ± 1.1% (1σ) for carbon ions. The measurements performed with the ionisation chamber indicate this slight underdosage with a dose difference of −1.7% for protons and −1.0% for carbon ions. The profiles measured by radiochromic films showed an acceptable homogeneity of about 3%. Conclusions: Alanine dosimeters are suitable detectors for dosimetry audits in ion beam therapy and the presented end-to-end test is

Dosimetry auditing procedure with alanine dosimeters for light ion beam therapy.

Science.gov (United States)

Ableitinger, Alexander; Vatnitsky, Stanislav; Herrmann, Rochus; Bassler, Niels; Palmans, Hugo; Sharpe, Peter; Ecker, Swantje; Chaudhri, Naved; Jäkel, Oliver; Georg, Dietmar

2013-07-01

In the next few years the number of facilities providing ion beam therapy with scanning beams will increase. An auditing process based on an end-to-end test (including CT imaging, planning and dose delivery) could help new ion therapy centres to validate their entire logistic chain of radiation delivery. An end-to-end procedure was designed and tested in both scanned proton and carbon ion beams, which may also serve as a dosimetric credentialing procedure for clinical trials in the future. The developed procedure is focused only on physical dose delivery and the validation of the biological dose is out of scope of the current work. The audit procedure was based on a homogeneous phantom that mimics the dimension of a head (20 × 20 × 21 cm(3)). The phantom can be loaded either with an ionisation chamber or 20 alanine dosimeters plus 2 radiochromic EBT films. Dose verification aimed at measuring a dose of 10Gy homogeneously delivered to a virtual-target volume of 8 × 8 × 12 cm(3). In order to interpret the readout of the irradiated alanine dosimeters additional Monte Carlo simulations were performed to calculate the energy dependent detector response of the particle fluence in the alanine detector. A pilot run was performed with protons and carbon ions at the Heidelberg Ion Therapy facility (HIT). The mean difference of the absolute physical dose measured with the alanine dosimeters compared with the expected dose from the treatment planning system was -2.4 ± 0.9% (1σ) for protons and -2.2 ± 1.1% (1σ) for carbon ions. The measurements performed with the ionisation chamber indicate this slight underdosage with a dose difference of -1.7% for protons and -1.0% for carbon ions. The profiles measured by radiochromic films showed an acceptable homogeneity of about 3%. Alanine dosimeters are suitable detectors for dosimetry audits in ion beam therapy and the presented end-to-end test is feasible. If further studies show similar results, this dosimetric audit could be

Acoustic evaluation of polymer gel dosimeters

International Nuclear Information System (INIS)

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

2002-01-01

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

The accreditation programs and proficiency test in Taiwan for personnel dosimeter services (1991-1998)

International Nuclear Information System (INIS)

Lee, B.T.; Hwang, W.S.; Su, S.H.

2000-01-01

According to the ionizing radiation safety regulation approved by the ROC Atomic Energy Council (AEC), personnel dosimeter processors shall be accredited by the Chinese National Laboratory Accreditation (CNLA) program before offering dosimeter services and shall be accredited every two years (now has been rescheduled to be every three years since 1996). The aim of this program is to secure quality and technical capability of personnel dosimeters, and to provide systematic improvement for the internal calibration and testing laboratory applying for accreditation by means of assessment procedures. The criteria used to evaluate the capability at laboratories are ISO/IEC 25 (1990) and technical guide in different accreditation fields. The Institute of Nuclear Energy Research (INER) was entrusted by CNLA as the central laboratory to perform the proficiency test of personnel dosimeters for laboratory accreditation in December 1990. Such proficiency tests, based on ANSI N13.11 (1983), which is mainly separated to accident categories and protection categories which consists of eight parts of tests including single and mixture radiation of x-ray, gamma, beta and neutron, have been conducted four times, in 1991, 1993, 1995 and 1998. This paper deals with the test procedures and results of proficiency tests of personnel dosimeters from 1991 until 1998. The results of the four proficiency tests showed that, for accident categories, the pass rate is about 91%; for protection categories, the pass rate is about 98%. Meanwhile, the central laboratory will adopt a new version of HPS N13.11 (1993) to replace ANSI N13.11 (1983) as new criteria for the next proficiency test to be conducted in 2001. (author)

Water-resistant alanine-EPR dosimeter alanpol

International Nuclear Information System (INIS)

Peimel-Stuglik, Zofia; Bryl-Sandelewska, Teresa; Mirkowski, Krzysztof; Sartowska, Bozena

2009-01-01

Alanpol-water-resistant alanine-electron paramagnetic resonance (EPR) dosimeter consisted of cheap DL-α-alanine (9.8-27%) suspended in polyethylene matrix was presented. The rods (O=2.8 mm) were extruded from a hot mixture of alanine and low-density polyethylene. No grinding or crushing was used for alanine preparation. An orientation of cylindrical crystals, up to 300 μm long in parallel to the rod axis was responsible for some differences in a shape of EPR signal. These differences had no negative consequences for dosimetric applications. Signal-to-dose dependence was linear up to 10 kGy. Standard deviation of dosimetric answer was up to ±1.8% and up to 2.4% for dosimeters with 9.8% and 27% of DL-α-alanine, respectively. Irradiation temperature coefficient for both dosimeters was equal 0.2%/ deg. C. Hydrophobic properties of polyethylene and small number of alanine crystals located on the surface of the rod led to high resistance of dosimeters to water and humidity. The 24 h soaking of irradiated dosimeters in liquid water-reduced EPR signals by 3-4% and by 2-3% for dosimeters with 27% and 9.8% of DL-α-alanine, respectively. Three month storage time of irradiated dosimeters in room conditions decreases EPR signal for ∼3%.

Gracing incidence small angle neutron scattering of incommensurate magnetic structures in MnSi thin films

Energy Technology Data Exchange (ETDEWEB)

Wiedemann, Birgit; Pfleiderer, Christian; Boeni, Peter [Physik Department, Technische Universitaet Muenchen (Germany); Zhang, Shilei; Hesjedal, Thorsten [Clarendon Laboratory, Department of Physics, University of Oxford (United Kingdom); Khaydukov, Yury; Soltwedel, Olaf; Keller, Thomas [Max-Planck-Institut fuer Festkoerperforschung (Germany); Max Planck Society, Outstation at FRM-II (Germany); Muehlbauer, Sebastian [Forschungsneutronenquelle Heinz Maier Leibnitz, Technische Universitaet Muenchen (Germany); Chacon, Alfonso [Physik Department, Technische Universitaet Muenchen (Germany); Forschungsneutronenquelle Heinz Maier Leibnitz, Technische Universitaet Muenchen (Germany)

2015-07-01

The topological stability of skyrmions in bulk samples of MnSi and the observation of spin transfer torque effects at ultra-low current densities have generated great interest in skyrmions in chiral magnets as a new route towards next generation spintronics devices. Yet, the formation of skyrmions in MBE grown thin films of MnSi reported in the literature is highly controversial. We report gracing incidence small angle neutron scattering (GISANS) of the magnetic order in selected thin films of MnSi grown by state of the art MBE techniques. In combination with polarised neutron reflectometry (PNR) and magnetisation measurements of the same samples our data provide direct reciprocal space information of the incommensurate magnetic order, clarifying the nature of magnetic phase diagram.

SDI-100 radiation dosimeter

International Nuclear Information System (INIS)

Zheng Zheng; Zhao Yongfu; Dai Honggui

1995-01-01

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

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

International Nuclear Information System (INIS)

Bache, Steven T.; Juang, Titania; Belley, Matthew D.; Koontz, Bridget F.; Yoshizumi, Terry T.; Kirsch, David G.; Oldham, Mark; Adamovics, John

2015-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-02-15

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

Exposure potential to neutrons of the Brazilian workers

International Nuclear Information System (INIS)

Martins, Marcelo M.; Almeida, Carlos E. de

1995-01-01

Nowadays, there are 222 neutron radioactive sources registered in use in Brazil, in addition to several neutron fields, power and research reactors and neutron generators. Secondary neutron fields can also be generated in particle accelerators by nuclear reactions with its shielding, the experimental set up and the conversion target. These neutron fields are very different, not only in their spectra but also in their fluences. Around 200 radiation workers are monthly monitored since 1983 by an albedo system. Of the evaluated dosimeters 4% only have shown neutron doses, being 13 mSv the maximum measured value. Most of these doses were received by workers of the oil-well logging and research activities users of 241 Am-Be sources. (author). 7 refs., 3 tabs

Layered magnets: polarized neutron reflection studies

Energy Technology Data Exchange (ETDEWEB)

Zabel, H; Schreyer, A [Ruhr-Univ. Bochum, Lehrstuhl fuer Experimentalphysik/Festkoerperphysik, Bochum (Germany)

1996-11-01

Neutron reflectivity measurements from extended surfaces, thin films and superlattices provide information on the chemical profile parallel to the film normal, including film thicknesses, average composition and interfacial roughness parameters. Reflectivity measurements with polarized neutrons are particularly powerful for analyzing the magnetic density profiles in thin films and superlattices in addition to chemical profiles. The basic theory of polarized neutron reflectivity is provided, followed by some examples and more recent applications concerning polarized neutron reflectivity studies from exchange coupled Fe/Cr superlattices. (author) 5 figs., 13 refs.

The Martin Marietta Energy Systems personnel neutron dosimetry program

International Nuclear Information System (INIS)

McMahan, K.L.

1991-01-01

Martin Marietta Energy Systems, Inc. (Energy Systems), manages five sites for the US Department of Energy. Personnel dosimetry for four of the five sites is coordinated through a Centralized External Dosimetry System (CEDS). These four sites are the Oak Ridge National Laboratory (ORNL), the Oak Ridge Y-12 Plant (Y-12), the Oak Ridge K-25 Site (K-25), and the Paducah Gaseous Diffusion Plant (PGDP). The fifth Energy Systems site, Portsmouth Gaseous Diffusion Plant, has an independent personnel dosimetry program. The current CEDS personnel neutron dosimeter was first issued in January 1989, after an evaluation and characterization of the dosimeters' response in the workplaces was performed. For the workplace characterization, Energy Systems contracted with Pacific Northwest Laboratory (PNL) to perform neutron measurements at selected locations at ORNL and Y-12. K-25 and PGDP were not included because their neutron radiation fields were similar to others already planned for characterization at ORNL and Y-12. Since the initial characterization, PNL has returned to Oak Ridge twice to perform follow up measurements, and another visit is planned in the near future

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