TLD territorial network in the Czech Republic

Energy Technology Data Exchange (ETDEWEB)

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

1996-12-31

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

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

International Nuclear Information System (INIS)

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

2018-01-01

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

Data processing of personnel exposure in TLD and film systems

International Nuclear Information System (INIS)

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

1979-01-01

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

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

International Nuclear Information System (INIS)

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

1979-01-01

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

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

International Nuclear Information System (INIS)

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

2012-01-01

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

RFID based TLD monitoring system - a prospective development

International Nuclear Information System (INIS)

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

2008-01-01

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

Automation at NRCN Dosimetry Laboratory

International Nuclear Information System (INIS)

Abraham, A.; Arad, I.; Mesing, M.; Levinson, S.; Weinstein, M.; Pelled, O.; Broida, A.; German, U.

2014-01-01

Running a dosimetric service based on TLD technology such as at the Nuclear Research Centre Negev (NRCN) requires a large group of workers to carry out simple mechanical actions such as opening and closing TLD badges, placing and removal of TLD cards from the badges and operating the TLD reader. These actions can be automated to free human resources for other assignments and to improve the quality assurance. At NRCN a project was undertaken to design and build a robotic system based on a manipulator arm. The design was based on the experience achieved with an earlier prototype (1,2). The system stores the TLD badges in special designed boxes, which are transported and stored in computer defined bins. The robotic arm loads and unloads TLD cards to the badges, and loads/unloads the cards to a magazine for the TLD reader. At the Nuclear Research Center Negev (NRCN) each badge is assigned to a specific worker and bears a sticker containing the worker's personal details, also in a machine readable form (barcode). In order to establish a proper QA check, a barcode reader records the information on the badge and on the TLD card placed in this badge and checks their compatibility with the information contained in the main database. Besides the TLD cards loading/unloading station, there is a contamination check station, a cards cleaning station and a UV irradiation box used to reduce the history dependent residual dose. The system was installed at the NRCN dosimetry laboratory It was successfully tested for several hundreds of cycles and will become operational in the first quarter of 2014. As far as we know, there is no similar product available for automatic handling in a TLD laboratory

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

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

International Nuclear Information System (INIS)

Haaslahti, J.

1986-01-01

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

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

International Nuclear Information System (INIS)

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

2008-01-01

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

Are Badges Useful in Education?: It Depends upon the Type of Badge and Expertise of Learner

Science.gov (United States)

Abramovich, Samuel; Schunn, Christian; Higashi, Ross Mitsuo

2013-01-01

Educational Badges are touted as an alternative assessment that can increase learner motivation. We considered two distinct models for educational badges; merit badges and videogame achievements. To begin unpacking the relationship between badges and motivation, we conducted a study using badges within an intelligent-tutor system for teaching…

Development and evaluation of new semi-automatic TLD reader software

International Nuclear Information System (INIS)

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

2018-01-01

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

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

International Nuclear Information System (INIS)

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

1994-01-01

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

Open badges for education: what are the implications at the intersection of open systems and badging?

Directory of Open Access Journals (Sweden)

June Ahn

2014-08-01

Full Text Available Badges have garnered great interest among scholars of digital media and learning. In addition, widespread initiatives such as Mozilla’s Open Badge Framework expand the potential of badging into the realm of open education. In this paper, we explicate the concept of open badges. We highlight some of the ways that researchers have examined badges as part of educational practice and also highlight the different definitions of open-ness that are employed in popular and scholarly thought. By considering badges from three different perspectives (motivation, pedagogy, and credential and the concept of openness from three different perspectives (production, access and appropriation we develop a framework to consider the tensions where these competing conceptions meet. This explication illuminates how the ideas of open and badges intersect, and clarifies situations where these concepts come into direct conflict or mutually enhance each other. Our analysis pinpoints and elucidates particular areas where research is needed to better understand the complex phenomenon of open badges, and also offers design considerations for developers, educators, and organizations that are actively involved in open badges.

Environmental dose measurement with microprocessor based portable TLD reader

International Nuclear Information System (INIS)

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

1996-01-01

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

Low-level dosimetry based on activation analysis of badge film, 1

International Nuclear Information System (INIS)

Morikawa, Kaoru; Yamashita, Kazuya; Inamoto, Kazuo; Maeda, Masayuki; Sato, Takashi; Ono, Koichi.

1988-01-01

Underexposed badge film contains a minor quantity of silver which corresponds to the low radiation dose even after completion of the photographic densitometry ; however, it cannot be detected with a photographic densitometer. We intended to clarify the minor silver content based on radioactivation analysis with thermal neutrons at KUR (Kyoto University Research Reactor). The natural silver consists of two stable nuclides, i.e., 107 Ag and 109 Ag. These can be activated with irradiation of thermal neutrons to two radionuclides, i.e., 108 Ag and 110 Ag. In this paper, through the activation analysis of an underexposed badge film, methods of measurements are shown regarding both 108 Ag produced by the 107 Ag (n, γ) reaction and 110 Ag by the 109 Ag (n, γ). After underexposed badge films were irradiated with thermal neutrons, some gamma-rays emitted from the radionuclides in the activated films were measured with a high pure Ge detector or a NaI (Tl) scintillation detector. The following results were obtained: (1) several elements such as silver, iodine, gold, antimony, manganese and copper were detected by activation analyses of films exposed to low level 60 Co gamma-rays, (2) the exposure vs 108 Ag or 110 Ag activity curve was linear in the lower dose range of 60 Co gamma-rays. These data indicate that low level radiation doses, which is indeterminable by ordinary photographic densitometry, can be estimated by activation analysis of silver atoms in badge films. (author)

Stratified dosimetric badge

International Nuclear Information System (INIS)

Cox, F.M.; Shoffner, B.M.; Chamberlain, J.D.; Shrader, E.F.

1974-01-01

That badge is of the type comprising a perforated rigid supporting member of nonluminescent matter and a film-like non-luminescent foil rendered pervious to light according to the code and mounted so as to be in register with holes in the supporting member. The badge is characterized in that it comprises a depressed portion in the upper surface of the supporting member, the lower/surface of which is correspondingly bulged, in that the peripherical edges of the supporting member extend vertically downwards beyond said depressed portion, in that one or several ports in each of which a dosimeter is fixed are provided in said bulged portion, and in the said film-like foil is fixed within the peripheral edges of the supporting member, so that the badge lower surface to which said film-like foil is fixed comprises a planar surface. That badge can be used in particular for checking radiations to which individuals have been exposed [fr

Accuracy of effective dose estimation in personal dosimetry: a comparison between single-badge and double-badge methods and the MOSFET method.

Science.gov (United States)

Januzis, Natalie; Belley, Matthew D; Nguyen, Giao; Toncheva, Greta; Lowry, Carolyn; Miller, Michael J; Smith, Tony P; Yoshizumi, Terry T

2014-05-01

The purpose of this study was three-fold: (1) to measure the transmission properties of various lead shielding materials, (2) to benchmark the accuracy of commercial film badge readings, and (3) to compare the accuracy of effective dose (ED) conversion factors (CF) of the U.S. Nuclear Regulatory Commission methods to the MOSFET method. The transmission properties of lead aprons and the accuracy of film badges were studied using an ion chamber and monitor. ED was determined using an adult male anthropomorphic phantom that was loaded with 20 diagnostic MOSFET detectors and scanned with a whole body CT protocol at 80, 100, and 120 kVp. One commercial film badge was placed at the collar and one at the waist. Individual organ doses and waist badge readings were corrected for lead apron attenuation. ED was computed using ICRP 103 tissue weighting factors, and ED CFs were calculated by taking the ratio of ED and badge reading. The measured single badge CFs were 0.01 (±14.9%), 0.02 (±9.49%), and 0.04 (±15.7%) for 80, 100, and 120 kVp, respectively. Current regulatory ED CF for the single badge method is 0.3; for the double-badge system, they are 0.04 (collar) and 1.5 (under lead apron at the waist). The double-badge system provides a better coefficient for the collar at 0.04; however, exposure readings under the apron are usually negligible to zero. Based on these findings, the authors recommend the use of ED CF of 0.01 for the single badge system from 80 kVp (effective energy 50.4 keV) data.

Studies on α-Al2O3: C based optically stimulated luminescence badge for eye lens monitoring applications

International Nuclear Information System (INIS)

Kumar, Munish; Kulkarni, M.S.; Ratna, P.; Gaikwad, N.; Tripathi, S.M.; Sharma, S.D.; Babu, D.A.R.; Bhatnagar, Amit; Muthe, K.P.; Sharma, D.N.

2014-01-01

The prototype two element eye-lens dosimeter badge based on indigenously developed α-Al 2 O 3 : C optically stimulated luminescence dosimeter was investigated comprehensively for its suitability for eye-lens monitoring applications. The badge is calibrated to measure the eye-lens dose in terms of H p (3). The minimum measurable dose using the eye-lens dosimeter badge is observed to be ∼ 35 μSv. This prototype eye-lens dosimeter badge was found to be suitable for measuring doses from X-rays, beta and gamma radiations to the eye-lens. The satisfactory performance of the prototype two element eye-lens dosimeter badge along with its attractive features such as multiple readout, less processing time, very good beta response uniquely position it for monitoring the eye-lens dose are presented. (author)

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

Energy Technology Data Exchange (ETDEWEB)

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

2004-07-01

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

Badging people not on your payroll.

Science.gov (United States)

Hogan, Mary Alice

2009-01-01

A complex badging process to create a culture of safety in a medical center is described by the author. Badging is not only used to control access by employees, but non-employees--medical students, vendors, contractors, volunteers, etc.--are subjected to similar processing procedures before they can be issued badges.

Digital Badges in Education

Science.gov (United States)

Gibson, David; Ostashewski, Nathaniel; Flintoff, Kim; Grant, Sheryl; Knight, Erin

2015-01-01

Digital badges provide new affordances for online educational activities and experiences. When used with points and leaderboards, a badge can become a gamification element allowing learners to compete with themselves or others, and to know how close they are to accomplishing a goal and acquiring its accompanying reputation. In this role, badges…

Passive Badge Assessment for Long-Term, Low-level Air Monitoring on Submarines: Acrolein Badge Validation

National Research Council Canada - National Science Library

Williams, Kimberly P; Rose-Pehrsson, Susan L; Kidwell, David A

2006-01-01

.... Passive badge monitors for acrolein detection were tested. Long-term sampling efficiency was evaluated for a 28-day period by comparing the response of the passive badge to an active tube sampling method...

Digital Badges for STEM Learning in Secondary Contexts: A Mixed Methods Study

Science.gov (United States)

Elkordy, Angela

The deficit in STEM skills is a matter of concern for national economies and a major focus for educational policy makers. The development of Information and Communications Technologies (ICT) has resulted in a rapidly changing workforce of global scale. In addition, ICT have fostered the growth of digital and mobile technologies which have been the learning context, formal and informal, for a generation of youth. The purpose of this study was to design an intervention based upon a competency-based, digitally-mediated, learning intervention: digital badges for learning STEM habits of mind and practices. Designed purposefully, digital badge learning trajectories and criteria can be flexible tools for scaffolding, measuring, and communicating the acquisition of knowledge, skills, or competencies. One of the most often discussed attributes of digital badges, is the ability of badges to motivate learners. However, the research base to support this claim is in its infancy; there is little empirical evidence. A skills-based digital badge intervention was designed to demonstrate mastery learning in key, age-appropriate, STEM competencies aligned with Next Generation Science Standards (NGSS) and other educational standards. A mixed methods approach was used to study the impact of a digital badge intervention in the sample middle and high school population. Among the findings were statistically significant measures which substantiate that in this student population, the digital badges increased perceived competence and motivated learners to persist at task.

CJEP will offer open science badges.

Science.gov (United States)

Pexman, Penny M

2017-03-01

This editorial announces the decision of the Canadian Journal of Experimental Psychology (CJEP) to offer Open Science Framework (OSF) Badges. The Centre for Open Science provides tools to facilitate open science practices. These include the OSF badges. The badges acknowledge papers that meet standards for openness of data, methods, or research process. They are now described in the CJEP Submission Guidelines, and are provided in the editorial. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Student perceptions of digital badges in a drug information and literature evaluation course.

Science.gov (United States)

Fajiculay, Jay R; Parikh, Bhavini T; Wright, Casey V; Sheehan, Amy Heck

2017-09-01

The purpose of this article is to describe student perceptions of implementation of digital badges in a drug information and literature evaluation course. Two digital badges were developed as voluntary learning opportunities. Student perceptions were obtained through pre- and post-survey instruments consisting of selected questions from the Motivated Strategies for Learning Questionnaire. The response rate was 69% (106/153). At baseline, 53% of respondents agreed that digital badges could help them better understand course material. More students agreed they would share earned digital badges on LinkedIn (68%) than Facebook (19%). Most students who earned digital badges agreed that badges helped increase their confidence in course material (73%), focus on specific learning objectives (55%), look deeper into course competencies (64%), and were a useful adjunct to the traditional teaching method (82%). Digital badges were perceived by students as a positive adjunct to learning and may provide a novel mechanism for development of an electronic skills-based portfolio. Copyright © 2017 Elsevier Inc. All rights reserved.

Evaluation algorithm for Hp (10), Hp (0.07) and response matrix in mixed fields of 137Cs+90Sr/90Y for badge TLD without use of its commercial holder

International Nuclear Information System (INIS)

Alvarez R, Jose T.; Tovar M, Victor M.; Castaneda P, Mario; Padilla, Ismael

2008-01-01

American standards HPS N 13.11 (1993, 2001) set up performance category tests for deep and shallow personal equivalent dose evaluated by dosimetry processors. These standards establish the parameters bias B, standard deviation S and tolerance level L, whose values indicate the deviations from the conventionally true value for the equivalent dose. On the other hand, for a right evaluation of the equivalent dose, all personal dosimetry systems have four basic components: badge, holder, reading protocol and dose evaluation algorithm. However, in Nuclear Plant Laguna Verde NPP dosimetry laboratory uses the badges Panasonic 802 A without Panasonic UD874AT holder, and instead employs a polyethylene holder bag to protect the badge from misuse. This situation disables the manufacturer algorithm designed for the combination: badge + holder. Therefore, the purpose of this work is to design a personal equivalent dose algorithm for this badge + bag, such this corrected algorithm let fulfill the HPS N 13.11 (1993) categories II, IV, V and VII. The algorithm starts from the readings of the elements: E1, E2, E3 and E4, only corrected by their element correction factor ECF. Additionally, we characterize the badge + bag by means of the response function for: 137 Cs, 85 Kr and 90 Sr/ 90 Y radiation fields. Finally, for validation of the algorithm one verifies that parameters B, S and L accomplish with the limits indicated by the standard. (author)

Engaging Undergraduate Students in a Co-Curricular Digital Badging Platform

Science.gov (United States)

Coleman, Jonathan D.

2018-01-01

Digital badging continues to garner attention in the educational community. What remains to be seen is how badging will interact with traditional curricular elements. While concerns have been raised about using badges as extrinsic motivators in coursework, there are alternate areas of application for digital badging. Badges may actually serve to…

Radon-film-badges by solid radiators to complement track detector-based radon monitors

International Nuclear Information System (INIS)

Tommasino, L.; Tommasino, M.C.; Viola, P.

2009-01-01

Existing passive radon monitors, based on track detectors, present many shortcomings, such as a limited response sensitivity for one-week-indoor measurements and a limited response linearity for the assessment of large radon exposures indoors, in thermal spa, in caves, and in soil. Moreover, for in-soil measurements these monitors are too bulky and are often conducive to wrong results. For what concerns the radon-in-water measurements, they are just not suitable. A new generation of passive radon monitors is introduced in this paper, which are very similar to the compact badges used in neutron- and gamma-dosimetry and will be referred to as radon-film-badges. These film-badges are formed by thin-film radiators with suitable radon-sorption characteristics, facing track detectors. The key strategy adopted for these radiators is to exploit an equilibrium type of radon sorption in solids. Even though this new generation of passive monitors is at its infancy, it appears already clear that said monitors make it finally possible to overcome most of the shortcomings of existing passive radon monitors. These devices are uniquely simple and can be easily acquired by any existing radon service to complement their presently used passive radon monitors with little or no effort.

MOOC Badging and the Learning Arc

OpenAIRE

Cross, Simon; Galley, Rebecca

2012-01-01

The first part of the post expands on some of our thinking behind the digital badging strategy used in the 2012 OLDS MOOC by using a pictorial representation to explain the place of the badges in the course. This is predicated on (a) the idea that a course, just like a novel, a movie or a video game, contains a broad central 'story arc' - a 'learning arc' or journey with a start (beginning of course) and an end, and (b) the idea that there are different types of badge that have different rela...

Environmental monitoring with a portable TLD system

Energy Technology Data Exchange (ETDEWEB)

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

1984-01-01

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

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

International Nuclear Information System (INIS)

Saez Vergara, J.C.

1990-01-01

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

Matrix effect on leaching of Bisphenol A diglycidyl ether (BADGE) from epoxy resin based inner lacquer of aluminium tubes into semi-solid dosage forms.

Science.gov (United States)

Lipke, Uwe; Haverkamp, Jan Boris; Zapf, Thomas; Lipperheide, Cornelia

2016-04-01

To study the impact of different semi-solid dosage form components on the leaching of Bisphenol A (BPA) and Bisphenol A diglycidyl ether (BADGE) from the epoxy resin-based inner lacquer of aluminium tubes, the tubes were filled with different matrix preparations and stored at an elevated temperature. Despite compliance with the European Standards EN 15348 and EN 15766 on porosity and polymerisation of internal coatings of aluminium tubes, the commercially available tubes used in the study contained an increased amount of polymerisation residues, such as unbound BPA, BADGE and BADGE derivatives in the lacquer, as determined by acetonitrile extraction. Storage of Macrogol ointments in these tubes resulted in an almost quantitative migration of the unbound polymerisation residues from the coating into the ointment. In addition, due to alterations observed in the RP-HPLC chromatograms of the matrix spiked with BADGE and BADGE derivatives it is supposed that the leachates can react with formulation components. The contamination of the medicinal product by BPA, BADGE and BADGE derivatives can be precluded by using aluminium tubes with an internal lacquer with a low degree of unbound polymerisation residues. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Quality assurance of the manual OSLD Badge based personnel monitoring system

International Nuclear Information System (INIS)

Kumar, Munish; Gaonkar, U.P.; Koul, D.K.; Datta, D.; Singh, S.K.; Rakesh, R.B.; Kulkarni, M.S.; Ratna, P.

2018-01-01

Optically stimulated luminescence (OSL) based technique is widely used for monitoring of radiation workers exposed to x, gamma and beta radiations. Features such as multiple readout, short processing time, better beta response, absence of infra red signal (no heating), flexibility in the dosimeter design using binders or substrates having low melting point are associated advantages. Presently α-Al 2 O 3 :C and BeO based dosimeters are popularly used for personnel monitoring applications worldwide. The present paper describe results of the external quality control check (QAC) tests performed for the present OSLD badge based personnel monitoring system. The results were analyzed as per ANSI criteria and Trumpet curve methods

Postal TLD audit in radiotherapy in the Czech Republic

International Nuclear Information System (INIS)

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

2014-01-01

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

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

Tweeting badges: user motivations for displaying achievement in publicly networked environments.

Science.gov (United States)

Kwon, K Hazel; Halavais, Alexander; Havener, Shannon

2015-02-01

Badge systems, a common mechanism for gamification on social media platforms, provide a way for users to present their knowledge or experience to others. This study aims to contribute to the understanding of why social media users publicize their achievements in the form of online badges. Five motivational factors for badge display in public networked environments are distinguished-self-efficacy, social incentives, networked support, passing time, and inattentive sharing-and it is suggested that different badge types are associated with different motivations. System developers are advised to consider these components in their designs, applying the elements most appropriate to the communities they serve. Comparing user motivations associated with badges shared across boundaries provides a better understanding of how online badges relate to the larger social media ecosystem.

Using digital badges in South Africa informing the validation of a multi-channel open badge system at a German university

CSIR Research Space (South Africa)

Niehaus, E

2017-05-01

Full Text Available strategy, remains an area to explore. One of the most crucial points of concern currently with digital badging is how to validate or credit a competence or skillset and what value this validation will carry for the individual. The Mozilla digital badge...

Badge Office Process Analysis

Energy Technology Data Exchange (ETDEWEB)

Haurykiewicz, John Paul [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dinehart, Timothy Grant [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Parker, Robert Young [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-05-12

The purpose of this process analysis was to analyze the Badge Offices’ current processes from a systems perspective and consider ways of pursuing objectives set forth by SEC-PS, namely increased customer flow (throughput) and reduced customer wait times. Information for the analysis was gathered for the project primarily through Badge Office Subject Matter Experts (SMEs), and in-person observation of prevailing processes. Using the information gathered, a process simulation model was constructed to represent current operations and allow assessment of potential process changes relative to factors mentioned previously. The overall purpose of the analysis was to provide SEC-PS management with information and recommendations to serve as a basis for additional focused study and areas for potential process improvements in the future.

Opportunities and Challenges with Digital Open Badges

Science.gov (United States)

Farmer, Tadd; West, Richard E.

2016-01-01

With increasing interest in competency and outcome-based education, and the blending of formal and informal learning, there is increasing need for credentials to match these learning paradigms. In this article, the authors discuss the benefits, challenges, and potential future directions for open digital badges--one potential alternative…

The response of film badge dosemeters to high energy photon radiation

International Nuclear Information System (INIS)

Playle, T.S.

1988-12-01

The sites of the earlier magnox reactor power stations at Berkeley and Bradwell in the United Kingdom are subject to 6 MeV photon radiation from the coolant gas. Since 1966 the Central Electricity Generating Board has included in its film badge personal dosimetry procedures an algorithm for applying a correction for over-response to high energy photon radiation. The correction is based on laboratory irradiations using a source of pure 6 MeV photon radiation. Recently, the opportunity arose to evaluate the response of the film badges at locations around the Berkeley reactors where spectrum-dependent dose equivalent rates had been measured. This report compares the response of the film badge in these characterised radiation environments with the response measured in the calibration laboratory. It is concluded that in the location where measurements were made, the high energy enhancement of measured dose was obscured by the effects of low energy scattered radiation, and it is considered that this will be the case for all practical situations on the power station site. There is therefore no advantage in using the 6 MeV correction factors for routine film badge dosimetry in these locations. (author)

Adding Badging to a Marketing Simulation to Increase Motivation to Learn

Science.gov (United States)

Saxton, M. Kim

2015-01-01

Badging has become a popular tool for obtaining social recognition for personal accomplishments. This innovation describes a way to add badging to a marketing simulation to increase student motivation to achieve the simulation's goals. Assessments indicate that badging both motivates students to perform better and helps explain students' perceived…

The Effect of Achievement Badges on Students’ Behavior: An Empirical Study in a University-Level Computer Science Course

Directory of Open Access Journals (Sweden)

Lasse Hakulinen

2015-02-01

Full Text Available Achievement badges are a form of gamification that are used in an attempt to increase user engagement and motivation in various systems. A badge is typically a graphical icon that appears as a reward for the user after reaching an achievement but that has no practical value. In this study, we describe and evaluate the use of achievement badges in the ANONYMOUS online learning environment where students solve interactive, automatically assessed exercises in a Data Structures and Algorithms course throughout the semester. We conducted an experiment where the students (N=281 were randomly divided into a treatment and a control group, with and without achievement badges. Students in the treatment group were awarded achievement badges, for example, for solving exercises on the first attempt, doing exercises early, or solving all the exercises in a round with full points. Grading was the same for both groups, i.e. collecting badges did not affect the final grade, even though the exercise points themselves did. Students’ activity in ANONYMOUS was logged in order to find out whether the achievement badges had an effect on their behavior. We also collected numerical and open-ended feedback in order to find out students’ attitudes towards the badges. Our results show that achievement badges can be used to affect students’ behavior. Statistically significant differences were observed in the time used per exercise, number of sessions, total time, and normalized total number of badges. Furthermore, the majority of the students reported being motivated by the badges. Based on our findings, achievement badges seem to be a promising method to motivate students and to encourage desired study practices.

Carrying an anti-nuclear-power badge in the teaching profession

International Nuclear Information System (INIS)

Anon.

1990-01-01

The carrying of an anti-nuclear-power badge by a teacher during school hours violates the order to practice reticence in political activities. At the beginning of 1977 some teachers, the plaintiff as well, carried anti-nuclear-power badges, i.e. a round badge with a stylized red sun on a yellow background with the inscription 'Nuclear power - No, thank you'. Following a general direction by the educational authorities, the headmistress forbade plaintiff on 4.11.77 to visibly carry this badge during lessons. This protest having been without success, action was brought with partial success at the Administrative and Higher Administrative Court. The Federal Administrative Court dismissed the case. (orig./HSCH) [de

Tutoring Online Tutors: Using Digital Badges to Encourage the Development of Online Tutoring Skills

Science.gov (United States)

Hrastinski, Stefan; Cleveland-Innes, Martha; Stenbom, Stefan

2018-01-01

Online tutors play a critical role in e-learning and need to have an appropriate set of skills in addition to subject matter expertise. This paper explores how digital badges can be used to encourage the development of online tutoring skills. Based on previous research, we defined three digital badges, which are examples of essential tutoring…

Glass badge dosimetry system for large scale personal monitoring

International Nuclear Information System (INIS)

Norimichi Juto

2002-01-01

Glass Badge using silver activated phosphate glass dosemeter was specially developed for large scale personal monitoring. And dosimetry systems such as an automatic leader and a dose equipment calculation algorithm were developed at once to achieve reasonable personal monitoring. In large scale personal monitoring, both of precision for dosimetry and confidence for lot of personal data handling become very important. The silver activated phosphate glass dosemeter has basically excellent characteristics for dosimetry such as homogeneous and stable sensitivity, negligible fading and so on. Glass Badge was designed to measure 10 keV - 10 MeV range of photon. 300 keV - 3 MeV range of beta, and 0.025 eV - 15 MeV range of neutron by included SSNTD. And developed Glass Badge dosimetry system has not only these basic characteristics but also lot of features to keep good precision for dosimetry and data handling. In this presentation, features of Glass Badge dosimetry systems and examples for practical personal monitoring systems will be presented. (Author)

Measurement of TLD Albedo response on various calibration phantoms

International Nuclear Information System (INIS)

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

1996-01-01

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

User's guide for survey-meter- and film-badge-dosimetry data bases

International Nuclear Information System (INIS)

Phillips, W.G.; Sherman, S.; Young, R.

1981-05-01

This manual describes the data storage and retrieval system designed by Environmental Monitoring Systems Laboratory Las Vegas (EMSL-LV) for radiation exposure data recorded in offsite areas during and after nuclear weapons tests conducted at the Nevada Test Site in the 1950's and early 1960's. Referred to hereinafter as the EMSL-LV system, this system contains two distinct subsets of offsite radiological measurements collected during early nuclear atmospheric tests at the Nevada Test Site. The purpose of the manual is to present the methods for using the EMSL-LV system to examine all or any portion of either data subset. The two distinct subsets which comprise the EMSL-LV system are survey meter data and film badge dosimetry data. The survey meter data consist of readings obtained from portable radiation monitoring instruments used around the Nevada Test Site during the 1950's and early 1960's to measure radiation exposure rates resulting from the nuclear testing program. The dosimetry data consist of measurements of integrated radiation exposure made with film badge type dosimeters in areas surrounding the Nevada Test Site

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

International Nuclear Information System (INIS)

Taylor, M.L.

2011-01-01

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

Digital Badges and Library Instructional Programs: Academic Library Case Study

Science.gov (United States)

Rodgers, Andrea Reed; Puterbaugh, Mark

2017-01-01

This case study describes the planning, implementation, and migration process of Eastern University Library's information literacy digital badge. Prior to implementing a badging program, information literacy sessions were informally embedded in first-year college writing courses as a "one-shot" presentation. Spurred on by accreditation…

A new TLD system for space research

International Nuclear Information System (INIS)

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

1980-06-01

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

Developing a conceptual model for facilitating the issuing of digital badges in a resource constrained environment

CSIR Research Space (South Africa)

Salerno, S

2015-09-01

Full Text Available Gamification and digital badging are new concepts to the educational environment, where on completion of specific tasks, an individual can earn a badge or badges showing their achievement. Currently Mozilla Open Badges is the standard...

Gamification of Nursing Education With Digital Badges.

Science.gov (United States)

White, Meagan; Shellenbarger, Teresa

Digital badges (DBs) serve as an innovative approach to gamifying nursing education by engaging socially connected, technologically savvy nursing students in learning. Because assessment and credentialing mechanisms are housed and managed online, DBs are designed as visible indicators of accomplishment and skill. This article describes important considerations for faculty when incorporating game-based pedagogies such as DB into nursing education and identifies potential pitfalls with DB use that faculty should consider.

Employer Perceptions of Critical Information Literacy Skills and Digital Badges

Science.gov (United States)

Raish, Victoria; Rimland, Emily

2016-01-01

Digital badges are an educational innovation used to measure learning of specific skills, such as information literacy. However, few studies have quantitatively surveyed employers for their perceptions about information literacy skills or digital badges. An online survey was developed and sent to employers to gauge perceptions of information…

Analysis of glow curves of TL readouts of CaSO4:Dy teflon based TLD badge in semiautomatic TLD badge reader

International Nuclear Information System (INIS)

Pradhan, S.M.; Sneha, C.; Adtani, M.M.

2010-01-01

The facility of glow curve storage and recall provided in the reader software is helpful for manual screening of the glow curves; however no further analysis is possible due to absence of numerical TL data at the sampling intervals. In the present study glow curves are digitized by modifying the reader software and then normalized to make them independent of the dose. The normalized glow curves are then analyzed by dividing them into five equal parts on time scale. This method of analysis is used to correlate the variation of total TL counts of the three discs with time elapsed post irradiation

Effects of the Badge Mechanism on Self-Efficacy and Learning Performance in a Game-Based English Learning Environment

Science.gov (United States)

Yang, Jie Chi; Quadir, Benazir; Chen, Nian-Shing

2016-01-01

A growing number of studies have been conducted on digital game-based learning (DGBL). However, there has been a lack of attention paid to individuals' self-efficacy and learning performance in the implementation of DGBL. This study therefore investigated how the badge mechanism in DGBL enhanced users' self-efficacy in the subject domain of…

Badges to Acknowledge Open Practices: A Simple, Low-Cost, Effective Method for Increasing Transparency.

Directory of Open Access Journals (Sweden)

Mallory C Kidwell

2016-05-01

Full Text Available Beginning January 2014, Psychological Science gave authors the opportunity to signal open data and materials if they qualified for badges that accompanied published articles. Before badges, less than 3% of Psychological Science articles reported open data. After badges, 23% reported open data, with an accelerating trend; 39% reported open data in the first half of 2015, an increase of more than an order of magnitude from baseline. There was no change over time in the low rates of data sharing among comparison journals. Moreover, reporting openness does not guarantee openness. When badges were earned, reportedly available data were more likely to be actually available, correct, usable, and complete than when badges were not earned. Open materials also increased to a weaker degree, and there was more variability among comparison journals. Badges are simple, effective signals to promote open practices and improve preservation of data and materials by using independent repositories.

Analysis of reaction products of food contaminants and ingredients: bisphenol A diglycidyl ether (BADGE) in canned foods.

Science.gov (United States)

Coulier, Leon; Bradley, Emma L; Bas, Richard C; Verhoeckx, Kitty C M; Driffield, Malcolm; Harmer, Nick; Castle, Laurence

2010-04-28

Bisphenol A diglycidyl ether (BADGE) is an epoxide that is used as a starting substance in the manufacture of can coatings for food-contact applications. Following migration from the can coating into food, BADGE levels decay and new reaction products are formed by reaction with food ingredients. The significant decay of BADGE was demonstrated by liquid chromatographic (LC) analysis of foodstuffs, that is, tuna, apple puree, and beer, spiked with BADGE before processing and storage. Life-science inspired analytical approaches were successfully applied to study the reactions of BADGE with food ingredients, for example, amino acids and sugars. An improved mass balance of BADGE was achieved by selective detection of reaction products of BADGE with low molecular weight food components, using a successful combination of stable isotopes of BADGE and analysis by LC coupled to fluorescence detection (FLD) and high-resolution mass spectrometric (MS) detection. Furthermore, proteomics approaches showed that BADGE also reacts with peptides (from protein digests in model systems) and with proteins in foods. The predominant reaction center for amino acids, peptides, and proteins was cysteine.

Superciliums in white-eared hummingbirds as badges of status signaling dominance.

Science.gov (United States)

González-García, Juan Manuel; Lara, Carlos; Quesada, Javier; Chávez-Zichinelli, Carlos A; Serrano-Meneses, Martín A

2018-04-03

The role of badges as indicators of contest ability has been previously described. In hummingbirds, the exhibition of a badge is expected to save energy expenditure in agonistic interactions and to favor energy intake. Here, we investigate whether variable supercilium size in the white-eared hummingbird has a role in dominance status signaling. Firstly, 45 hummingbird males were captured and their superciliums were photographed to investigate variation in size and any possible allometric relationships. Secondly, 42 male birds were used to analyze whether the supercilium has a role in dominance status signaling in a dyadic contest. We found that supercilium size varied continuously but that despite variability between individuals, there was no relationship between supercilium size and body size. However, our dyad experiment indicated that birds with larger badges were able to make more visits to the feeders than individuals with smaller badges. We suggest a status signaling function of the supercilium.

Teachers' Perceptions of Digital Badges as Recognition of Professional Development

Science.gov (United States)

Jones, W. Monty; Hope, Samantha; Adams, Brianne

2018-01-01

This mixed methods study examined teachers' perceptions and uses of digital badges received as recognition of participation in a professional development program. Quantitative and qualitative survey data was collected from 99 K-12 teachers who were awarded digital badges in Spring 2016. In addition, qualitative data was collected through…

Radiation monitoring policy at the advanced light source

International Nuclear Information System (INIS)

Donahue, R.; Heinzelman, K.; Perdue, G.

1998-01-01

When the accelerator first began operation it was decided that, until we had the necessary dosimetry data to decide otherwise, we would badge the entire worker and experimental population. Each person was issued a dosimetry badge that contained 4 TLD elements. Badges were processed on a monthly basis. After three years of analyzing a total of 65,000 TLD elements, the decision was made to modify the radiation monitoring policy at the ALS. Only those individuals in the workforce that have any potential for exposure, no matter how small, would be badged. Subsequently, DOE conducted an independent review of the ALS radiation monitoring and dosimetry program. This review concluded that the ALS program, if expanded as proposed, would be adequate under the 10 CFR 835 Rule to establish radiation exposures to an acceptable level of confidence. The review team recommended the ALS provide more comprehensive documentation on the basis for its radiation protection and monitoring program. This document describes the technical justification for that program

Development of CaSO4:Dy based ring dosemeter for extremity monitoring of radiation workers in India

International Nuclear Information System (INIS)

Srivastava, Kshama; Meenal, P.; Bhagat, R.V.; Singh, R.; Kolambe, D.H.; Chougaonkar, M.P.; Sapra, B.K.

2014-01-01

Extremity dosemeters are required to be worn in cases where the dose to extremities is expected to be significantly greater than the dose to the whole body. In India, CaSO 4 :Dy based three element personnel monitoring TLD badge worn at chest and wrist level are used for whole body and extremity monitoring, respectively. Presently no official/legal finger dosemeter is available for extremity monitoring for radiation workers in the country. To cater to the long standing requirement of finger dosimeter, a new compact three-element Extremity Ring Badge Dosemeter (ERBD) has been developed for measurement of the equivalent doses received by the extremities of radiation workers in terms of operational quantity Hp(0.07). It was aimed to meet the performance requirement of IEC/ISO standards. This paper gives the design detail and result of experimental studies of ERB dosemeter

X-rays individual dose assessment using TLD dosimeters

International Nuclear Information System (INIS)

Salas, Carlos

2008-01-01

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

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

International Nuclear Information System (INIS)

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

2013-01-01

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

Next Generation Model 8800 Automatic TLD Reader

International Nuclear Information System (INIS)

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

1999-01-01

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

An automated thermoluminescence dosimetry (TLD) system

International Nuclear Information System (INIS)

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

1979-01-01

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

TLD audit in radiotherapy in the Czech Republic

International Nuclear Information System (INIS)

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

1998-01-01

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

Girl Scout Camps and Badges: Engaging Girls in NASA Science

Science.gov (United States)

Harman, P. K.; DeVore, E. K.

2017-12-01

Reaching for the Stars: NASA Science for Girl Scouts (Girl Scout Stars) disseminates NASA STEM education-related resources, fosters interaction between Girl Scouts and NASA Subject Matter Experts (SMEs), and engages Girl Scouts in NASA science and programs through space science badges and summer camps. A space science badge is in development for each of the six levels of Girl Scouts: Daisies, Grades K - 1; Brownies, Grades 2 -3; Juniors, Grades 4 -5; Cadettes, Grades 6 -8; Seniors, Grades 9 -10: and Ambassadors, Grades 11 -12. Daisy badge will be accomplished by following three steps with two choices each. Brownie to Ambassador badges will be awarded by completing five steps with three choices for each. The badges are interwoven with science activities, role models (SMEs), and steps that lead girls to explore NASA missions. External evaluators monitor three rounds of field-testing and deliver formative assessment reports. Badges will be released in Fall of 2018 and 2019. Girl Scout Stars supports two unique camp experiences. The University of Arizona holds an Astronomy Destination, a travel and immersion adventure for individual girls ages 13 and older, which offers dark skies and science exploration using telescopes, and interacting with SMEs. Girls lean about motion of celestial objects and become astronomers. Councils send teams of two girls, a council representative and an amateur astronomer to Astronomy Camp at Goddard Space Flight Center. The teams were immersed in science content and activities, and a star party; and began to plan their new Girl Scout Astronomy Clubs. The girls will lead the clubs, aided by the council and amateur astronomer. Camps are evaluated by the Girl Scouts Research Institute. In Girl Scouting, girls discover their skills, talents and what they care about; connect with other Girl Scouts and people in their community; and take action to change the world. This is called the Girl Scout Leadership Experience. With girl-led, hands on

Badges of modern slavery

OpenAIRE

Paz-Fuchs, Amir

2016-01-01

Notwithstanding the 19th century formal abolition of slavery as legal ownership of people, modern slavery and forced labour have not been consigned to the past. In fact, their existence is more widespread, and made more difficult to tackle due to the lack of formal, legal criteria. This article suggests that reference to the past, historical institutions reveals seven ‘badges of slavery’ that are helpful in identifying occurrences of modern slavery and forced labour. These are: humiliation, o...

Measurement of the dose to the family members taking care of thyroid cancer patients undergoing I-131 therapy in nuclear medicine using TLD-100

International Nuclear Information System (INIS)

Zehtabian, M.; Dehghan, N.; Danaei Ghazanfarkhani, M.; Haghighatafshar, M.; Sina, S.

2017-01-01

The family members or friends of the patients undergoing treatment using radioiodine in nuclear medicine are inevitably exposed to ionization radiation. The purpose of this study is measurement of the dose received by the people taking care of the thyroid cancer patients treated by "1"3"1I. For this purpose, the dose amounts received by 29 people accompanying patients were measured using thermoluminescence dosimeters. A badge containing three TLD-100 chips was given to each caregiver. The people were asked to wear the badges for 24 days, when they are taking care of the patients. Finally the dose to each person was estimated by averaging the readings of the three TLDs. The measured dose amounts to the people were compared with the recommendations of international commissions. According to the results obtained in this study, the amounts of dose received by the caregivers were between 0.03 and 0.38 mSv, with the average of 0.12 mSv. By comparison of the results of this study with the recommendations of International Commission on Radiological Protection (ICRP), it can be observed that the dose to family members of the patients is less than the dose constraints. However, it is recommended that the caregivers be aware of the radiation protection principles in order to reduce their dose. (authors)

Dosimetric quality control in radiotherapy using TLD methodology

International Nuclear Information System (INIS)

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

2002-01-01

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

Recognising Informal Elearning with Digital Badging: Evidence for a Sustainable Business Model

Science.gov (United States)

Law, Patrina

2015-01-01

Digital badging as a trend in education is now recognised. It offers a way to reward and motivate, providing evidence of skills and achievements. Badged Open Courses (BOCs) were piloted by The Open University (OU) in 2013. The project built on research into the motivations and profiles of learners using free educational resources which the OU…

Operating experience of an automated TLD dispensing system at CORAL facility

International Nuclear Information System (INIS)

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

2016-01-01

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

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

International Nuclear Information System (INIS)

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

2013-01-01

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

Occupational exposure to ionizing radiation in Kenya

International Nuclear Information System (INIS)

Shadrack, Anthony Kiti

2008-01-01

Full text: This project is based on studies of radiation doses received by radiation workers from sample of radiation facilities in Nairobi, Kenya, using TLD badges. Radiation doses received by workers during performance of a few types of radiological exposures and application of sealed and unsealed radionuclides have been measured at a number of x ray departments (diagnostic radiology), radiotherapy and nuclear medicine and training and research. Radiation dose measurements were based on thermoluminescence dosimetry (TLD) techniques, using the laboratory facilities of the National Radiation Protection Laboratory (NRPL) at KNH, in Nairobi, Kenya. Evaluation of doses from TLD badges exposed to X-rays and radioisotopes are discussed. Nuclear medicine recorded the highest dose as compared to Radiotherapy, Training and research and Diagnostic radiology. Age and gender have no relation with dose absorption. Yearly average dose seems to have been reducing from 2002 to 2005, representing an improvement in radiation protection. Overall, the results show that radiation workers in Kenya are working under safe environments since the doses received are within acceptable limits of radiation protection. The data presented in this research provides a database, which should serve as a useful reference for comparison with similar studies in the future. (author)

Modification of beta dose evaluation algorithm for better accuracy in personnel monitoring

International Nuclear Information System (INIS)

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

2016-01-01

Dose due to beta radiations is the main contributor to the skin dose. Assessment of individual dose (whole body, skin, extremity) in India is based on CaSO 4 :Dy based Teflon embedded TLD badge used for personnel monitoring. The design of the dosemeter enables identification of radiation type which, in turn, allows use of radiation specific algorithm for dose evaluation. The difference of response of three discs of the TLD badge to beta radiation in beta/beta-gamma fields is due to the presence of different filters corresponding to the three discs. The response of disc under metal filter (D 1 ) to beta being negligible while that of open disc (D 3 ) is the maximum. The ratio of response of open disc to that under Perspex (D 3 /D 2 ) to beta is highly dependent on its energy and angle of incidence. Therefore estimation of dose due to beta is based on response of open disc corrected for the energy of beta using D 3 /D 2

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-07-01

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

Using badges to motivate and engage students

DEFF Research Database (Denmark)

Christensen, Inger-Marie F.; Hansen, Pernille Stenkil

The gap between educational institutions and students is widening. Many institutions maintain traditional methods and adopt new at a slow pace. Some educators and developers are looking to gamification to bridge the gap. This workshop will help participants’ explore the potential of badges...

Radiation monitoring at Pakistan research reactor

International Nuclear Information System (INIS)

Ali, A.

1984-05-01

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

Digital dosimetry and personal and environmental monitoring assembly

International Nuclear Information System (INIS)

Cerovac, Z.; Radalj, Z.; Prlic, I.; Cerovac, H.

1996-01-01

Film+TLD and film or TLD Dosimetry have a certain delay in dose reporting, since the reports on occupational doses are usually available to the users within 40 days after the actual exposure. This is particularly important when the dose is received within the short-time interval or when the radiation source has some technical failures. For this reason, the additional monitoring is recommendable. The common Dosimetry service in Croatia is well established and the data available shows that over 80% of occupationally exposed persons are working in medical facilities, mainly with x-ray sources. Dosimetry services in the country are providing three types of dosemeters, film dosemeter badge, film+TLD dosemeter badge or plane TLD badge. We have decided to introduce the palette of digital pocket dosemeters to be used at different workplaces occupationally exposed to ionizing radiation. After the first experience with the ALARA 1G digital dosemeter it came out that this type of ionizing radiation measuring device is suitable for the various non-occupational purposes. After some technical improvement and with some telecommunication electronics this device is usable as a point environmental measuring station. This means that the probe of the record any change in normal environmental radiation field, send the data to the central station and to raise alarm if necessary. That is why we have made a prototype for environmental monitoring able to be connected to any kind of telecommunication net. (author)

The IAEA/WHO TLD postal programme for radiotherapy hospitals

International Nuclear Information System (INIS)

Izewska, J.; Andreo, P.

2000-01-01

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

Measurement of the Dose to the Family Members Taking Care of Thyroid Cancer Patients Undergoing I-131 Therapy in Nuclear Medicine Using TLD-100.

Science.gov (United States)

Zehtabian, M; Dehghan, N; Danaei Ghazanfarkhani, M; Haghighatafshar, M; Sina, S

2017-05-01

The family members or friends of the patients undergoing treatment using radioiodine in nuclear medicine are inevitably exposed to ionization radiation. The purpose of this study is measurement of the dose received by the people taking care of the thyroid cancer patients treated by 131I. For this purpose, the dose amounts received by 29 people accompanying patients were measured using thermoluminescence dosimeters. A badge containing three TLD-100 chips was given to each caregiver. The people were asked to wear the badges for 24 days, when they are taking care of the patients. Finally the dose to each person was estimated by averaging the readings of the three TLDs. The measured dose amounts to the people were compared with the recommendations of international commitions. According to the results obtained in this study, the amounts of dose received by the caregivers were between 0.03 and 0.38 mSv, with the average of 0.12 mSv. By comparison of the results of this study with the recommendations of International Commission on Radiological Protection (ICRP), it can be observed that the dose to family members of the patients is less than the dose constraints. However, it is recommended that the caregivers be aware of the radiation protection principles in order to reduce their dose. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The Dose Estimation Formula Of Photon Radiation To Film Badge Of Kodak Type 2

International Nuclear Information System (INIS)

Rohmah, Nur

2000-01-01

Study to determine the formula of dose estimation for photon radiation to film badge of Kodak type 2 has been carried out. The irradiation was done by irradiated film badge of Kodak type 2 using photon sources of X-rays machine, 137 Cs and 60 Co. By determining the apparent dose and also the sensitivity values each filters of the calibration curve and the weighting factors of energy dependence curve, the formula of the dose estimation for film badge of Kodak type 2 could be obtained, i.e. H 1cm 2.066761E-02N ADPI-2 + 1.953342N ADAI - 8.946254N ADCu + 24.80611N ADSn/pb

Buy badges and help finance Cap Loisirs activities!

CERN Multimedia

2008-01-01

Please give a warm welcome to Cap Loisirs’ volunteers who will be manning a stand at the main entrance on Friday 8 February! In honour of St. Valentine’s Day, they will be selling a selection of 5 badges designed by artist Anna Sommer, depicting declarations of love by our friends from the animal kingdom. Price : Frs. 3.- per badge The aim of Fondation Cap Loisirs is to provide leisure activities for mentally handicapped children, adolescents and adults. The Foundation offers a wide range of activities which allow the mentally handicapped to enjoy quality leisure in areas as varied as culture, sport, tourism, travel and artistic expression. Fondation Cap Loisirs Rue de Monthoux 66 – 1201 Geneva – Tel: 022 731 86 00 – CCP Genève 12-5587-5 – caploisirs@caploisirs.ch – http://www.Caploisirs.ch

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-05-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2012-08-15

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

Recognising Informal Elearning with Digital Badging: Evidence for a Sustainable Business Model

Directory of Open Access Journals (Sweden)

Patrina Law

2015-11-01

Full Text Available Digital badging as a trend in education is now recognised. It offers a way to reward and motivate, providing evidence of skills and achievements. Badged Open Courses (BOCs were piloted by The Open University (OU in 2013. The project built on research into the motivations and profiles of learners using free educational resources which the OU makes available through its OpenLearn platform (Law, Perryman & Law, 2013. This research found that an increasing proportion of learners are keen to have their informal learning achievements recognised (Law & Law, 2014. Based on these data, a suite of free BOCs, assessed through the deployment of Moodle quizzes, was launched. This paper reports on evaluation of the BOCs and what we now know of the strategic importance of informal learning recognition. The initiative aligns with University strategies to provide accessible routes into formal learning for those who might not otherwise have the opportunity.

Design Principles for Digital Badges Used in Libraries

Science.gov (United States)

Rimland, Emily; Raish, Victoria

2017-01-01

Digital badges give libraries greater flexibility in delivering impactful instruction to students. They serve as flexible, stackable microcredentials that sequence an information literacy experience across the curriculum. Design considerations rooted in learning theory have a foundation through which to drive decisions. Information literacy badges…

Routine monitoring of eye dose; and reply

Energy Technology Data Exchange (ETDEWEB)

Palmer, K; Jeans, S P; Faulkner, K; Bardsley, R A; Love, H G

1985-12-01

This letter briefly reports the assessment at Papworth Hospital of the feasibility of monitoring eye doses of staff using a film badge worn on the shoulder in addition to the badge worn under the lead apron. For three consecutive months hand and eye (forehead) dose were monitored using TLDs, while shoulder and body dose, recorded under the lead apron, were measured with film badges. For the four doctors monitored, (two radiologists and two cardiologists) the shoulder badge somewhat overestimated the eye dose. In the case of nurses, the dose recorded by the shoulder badge was of a similar order to the TLD-recorded eye dose. The reply from the Christie Hospital at Manchester comments on the use of the shoulder badge and contends that the use of forehead dosemeters to measure eye dose is to be preferred whenever possible.

Environmental effects on TLD 100

International Nuclear Information System (INIS)

Lilley, E.; Howard, R.

1976-01-01

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

TLD audit in the radiotherapy at the national level

International Nuclear Information System (INIS)

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

1998-01-01

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

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

Science.gov (United States)

Kroutilķková, Daniela; Novotný, Josef; Judas, Libor

2003-02-01

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

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

International Nuclear Information System (INIS)

Kroutilikova, Daniela; Novotny, Josef; Judas, Libor

2003-01-01

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

Study of physical factors affecting the TLD readout

International Nuclear Information System (INIS)

Ahmed, Amira Abd Elrhman Ebrahim

2015-10-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2008-02-15

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

Automated TLD system for gamma radiation monitoring

International Nuclear Information System (INIS)

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

1979-01-01

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

Radiation Protection Services Division: progress report for 1992-1993

International Nuclear Information System (INIS)

Massand, O.P.; Murthy, B.K.S.

1994-01-01

This report describes the work of the Radiation Protection Services Division during 1993, for implementation of radiation safety in all institutions in India using radiation sources in medical, industrial and research applications. It gives information about personnel monitoring using photographic film and TLD badges, neutron monitoring badges, advisory and licensing services, regulation, transport of radioactive materials and periodic protection survey. About 33 publications by the staff of the Division are also listed. (author). 4 tabs

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

International Nuclear Information System (INIS)

Vatnitsky, S.; Izewska, J.

2002-01-01

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

Measurement of annual dose on porcelain using surface TLD method

International Nuclear Information System (INIS)

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

2001-01-01

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

TLD array for precise dose measurements in stereotactic radiation techniques

International Nuclear Information System (INIS)

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

1996-01-01

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

Estimation of whole body dose in an unusual event: spillage of radioactive material on the chair

International Nuclear Information System (INIS)

Adtani, M.M.; Biju, K.; Deshpande, M.D.; Shivde, R.K.; Kulkarni, V.V.

2005-01-01

The personnel monitoring in India is done using thermoluminescence dosimeters worn at chest level. In research institutions and in nuclear facilities where radiation sources are processed in dispersible forms, a remote possibility exists that radiation source entering in the area where installed monitor does not exist and the source may get spilled on chair and causing exposure to persons sitting on the chair. In such case TLD may not give the correct exposure as there is shielding of individuals body. An attempt is made to find out a factor for estimating the whole body dose by knowing the TLD badge dose or by measuring the gonad dose. Experiments are performed using TLDs and also measurement by teletector. Monte Carlo simulations are also done. It is observed that a factor of 8 to TLD Badge dose will give whole body dose if worker has received dose only on said chair or by applying a factor of 0.23 to dose measured at gonad level will give whole body dose. (author)

Analysis of reaction products of food contaminants and ingredients: Bisphenol A diglycidyl ether (BADGE) in canned foods

NARCIS (Netherlands)

Coulier, L.; Bradley, E.L.; Bas, R.C.; Verhoeckx, K.C.M.; Driffield, M.; Harmer, N.; Castle, L.

2010-01-01

Bisphenol A diglycidyl ether (BADGE) is an epoxide that is used as a starting substance in the manufacture of can coatings for food-contact applications. Following migration from the can coating into food, BADGE levels decay and new reaction products are formed by reaction with food ingredients. The

Optimal selection of TLD chips

International Nuclear Information System (INIS)

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

1996-01-01

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

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

International Nuclear Information System (INIS)

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

2003-01-01

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

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

International Nuclear Information System (INIS)

Duftschmid, K.E.

1986-01-01

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

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

International Nuclear Information System (INIS)

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

1999-01-01

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

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

International Nuclear Information System (INIS)

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

1976-01-01

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

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

International Nuclear Information System (INIS)

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

2018-01-01

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

A TLD dose algorithm using artificial neural networks

International Nuclear Information System (INIS)

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

1995-01-01

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

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

International Nuclear Information System (INIS)

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

1997-01-01

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

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

International Nuclear Information System (INIS)

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

1986-01-01

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

How to diagnose any type of TLD Reader?

International Nuclear Information System (INIS)

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

2013-01-01

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

Survey of medical radium installations in Wisconsin

International Nuclear Information System (INIS)

Tapert, A.C.; Lea, W.L.

1975-05-01

A radiation protection survey was performed at 70 medical radium installations in the State of Wisconsin. The requirements of the State's Radiation Protection Code were used as survey criteria. Radiation measurements of radium storage containers, radium capsule leakage tests, and monitoring of work surfaces for contamination were performed. Film badge monitoring data of whole body and extremity doses are presented for 221 individuals at 17 hospitals. Whole body doses during single treatments ranged from 10 to 1360 mrems per individual. The estimate of 500 mrems per treatment was determined as the dose aggregate to hospital personnel. Whole body doses from film badges are compared with analogous TLD doses. Four physicians and six technicians at nine hospitals participated in a study for monitoring the extremities with TLD. Cumulative extremity doses ranged from 28 to 6628 mrems per participant during the study. (U.S.)

Influence of TLD position on the estimate of fetal dose

International Nuclear Information System (INIS)

Majola, J.; Jamieson, T.J.

1995-11-01

This report examines the adequacy of the practice of using a single dosimeter worn at the front of the body as an estimate of the dose received by nuclear medicine technologies. In order to investigate this, a group of approximately 50 technologists at 9 different hospitals were double-badged, i.e. provided with front and back dosimeters, and the ratio of front to back dose computed. Both aggregate data and hospital-specific data are presented and accompanied by several forms of statistical analysis. Apparent trends and possible explanations are discussed. Recommendations are provided for additional studies relating to the badging of nuclear medicine technologists. (author). 125 refs., 15 tabs., 13 figs

Influence of TLD position on the estimate of fetal dose

Energy Technology Data Exchange (ETDEWEB)

Majola, J; Jamieson, T J [Science Applications International Corp., Ottawa, ON (Canada)

1995-11-01

This report examines the adequacy of the practice of using a single dosimeter worn at the front of the body as an estimate of the dose received by nuclear medicine technologies. In order to investigate this, a group of approximately 50 technologists at 9 different hospitals were double-badged, i.e. provided with front and back dosimeters, and the ratio of front to back dose computed. Both aggregate data and hospital-specific data are presented and accompanied by several forms of statistical analysis. Apparent trends and possible explanations are discussed. Recommendations are provided for additional studies relating to the badging of nuclear medicine technologists. (author). 125 refs., 15 tabs., 13 figs.

Minimizing TLD-DRD differences

International Nuclear Information System (INIS)

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

1987-01-01

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

The study of new calibration features in the Harshaw TLD system

International Nuclear Information System (INIS)

Luo, L. Z.

2007-01-01

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

Open digital badges in Open edX

OpenAIRE

Hickey, Daniel T.; Barba, Lorena A.; Lemoie, Kerri; Amigot, Michael; Ewens, Damian

2014-01-01

Slides for the presentation at the Open edX Conference, Cambridge, MA 2014.   This talk presented the first public update of our collaboration to implement open digital badges in Dr. Barba's new MOOC, "Practical Numerical Methods with Python." It's a collaboration between Indiana University's Center for Research on Learning and Technology (led by Prof. Daniel T. Hickey);  Prof. Lorena Barba and her team at George Washington University, with her partners at IBL Studios Education, and...

The personnel dosimetry record keeping system at AEE Winfrith

International Nuclear Information System (INIS)

Gill, D.W.

1979-09-01

Since May 1978 the exposure of personnel to external radiation has been assessed by Thermoluminescent Dosimetry, (TLD). The dosemeter consists of a TLD card similar to that used by the National Radiological Protection Board, held in a plastic badge designed at AEE Winfrith, and used in conjunction with a D A Pitman Ltd Type 605 Automatic Reader. The report describes the dosemeter, the operation of the dosimetry service and the system for maintaining a computerised record keeping system. (author)

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

International Nuclear Information System (INIS)

Vatnitsky, Stanislav; Izewska, Joanna

2002-01-01

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

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

Science.gov (United States)

Sadeghi, M; Sina, S; Faghihi, R

2015-12-01

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

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

International Nuclear Information System (INIS)

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

2016-01-01

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

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.

Measurement of radiocesium concentration in trees using cumulative gamma radiation dose rate detection systems - A simple presumption for radiocesium concentration in living woods using glass-badge based gamma radiation dose rate detection system

Energy Technology Data Exchange (ETDEWEB)

Yoshihara, T.; Hashida, S.N. [Plant Molecular Biology, Laboratory of Environmental Science, Central Research Institute of Electric Power Industry (CRIEPI), 1646 Abiko, Chiba 270-1194 (Japan); Kawachi, N.; Suzui, N.; Yin, Y.G.; Fujimaki, S. [Radiotracer Imaging Gr., Quantum Beam Science Center, Japan Atomic Energy Agency (JAEA), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Nagao, Y.; Yamaguchi, M. [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

2014-07-01

Radiocesium from the severe accident at the Fukushima Dai-ichi Nuclear Power Plant on 11 March 2011 contaminates large areas. After this, a doubt for forest products, especially of mushroom, is indelible at the areas. Pruned woody parts and litters are containing a considerable amount of radiocesium, and generates a problem at incineration and composting. These mean that more attentive survey for each subject is expected; however, the present survey system is highly laborious/expensive and/or non-effective for this purpose. On the other hand, we can see a glass-badge based gamma radiation dose rate detection system. This system always utilized to detect a personal cumulative radiation dose, and thus, it is not suitable to separate a radiation from a specific object. However, if we can separate a radiation from a specific object and relate it with the own radiocesium concentration, it would enable us to presume the specific concentration with just an easy monitoring but without a destruction of the target nature and a complicated process including sampling, pre-treatment, and detection. Here, we present the concept of the measurement and results of the trials. First, we set glass-badges (type FS, Chiyoda Technol Corp., Japan) on a part of bough (approximately 10 cm in diameter) of Japanese flowering cherry trees (Prunus x yedoensis cv. Somei-Yoshino) with four different settings: A, a direct setting without any shield; B, a setting with an aluminum shield between bough and the glass-badge; C, a setting with a lead shield between bough and the glass-badge; D, a setting with a lead shield covering the glass-badge to shut the radiation from the surrounding but from bough. The deduction between the amount of each setting should separate a specific radiation of the bough from unlimited radiation from the surrounding. Even if the hourly dose rate is not enough to count the difference, a moderate cumulative dose would clear the difference. In fact, results demonstrated a

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

Directory of Open Access Journals (Sweden)

Sadeghi M.

2015-12-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1998-12-31

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

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

International Nuclear Information System (INIS)

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

2007-01-01

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

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

Science.gov (United States)

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

2007-04-01

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

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

International Nuclear Information System (INIS)

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

2002-01-01

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

Feasibility Study on Sterilization of Badge using Radiation and Cultivation by Nano-bubble Water for Matsutake Mushroom Cultivation

International Nuclear Information System (INIS)

Jung, Inha

2013-12-01

This report on the 'Sterilization of Badge using Radiation and Cultivation by Nano-bubble Water for Matsutake Mushroom Cultivation' is belonged to the final report on the preliminary study of the first subject in 2013 for civilian project. This was complimented on the responsible of the Korea Atomic Energy Research Institute for 1 st of June 2013 to 30 th of November 2013. We are going to make sterilization the badge using the gamma ray and supplying the oxygen by nano-bubble oxygen rich water for cultivating the Matsutake Mushroom, instead of the conventional process of sterilization of the badge by hot steam over 120 .deg. C consuming over 8 hours and expensive ventilation system for supplying the fresh air for delivering the oxygen

Ionizing radiation source detection by personal TLD

International Nuclear Information System (INIS)

Marinkovic, O.; Mirkov, Z.

2002-01-01

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

NRC TLD Direct Radiation Monitoring Network

International Nuclear Information System (INIS)

Struckmeyer, R.; McNamara, N.

1991-12-01

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

Feasibility Study on Sterilization of Badge using Radiation and Cultivation by Nano-bubble Water for Matsutake Mushroom Cultivation

Energy Technology Data Exchange (ETDEWEB)

Jung, Inha

2013-12-15

This report on the 'Sterilization of Badge using Radiation and Cultivation by Nano-bubble Water for Matsutake Mushroom Cultivation' is belonged to the final report on the preliminary study of the first subject in 2013 for civilian project. This was complimented on the responsible of the Korea Atomic Energy Research Institute for 1{sup st} of June 2013 to 30{sup th} of November 2013. We are going to make sterilization the badge using the gamma ray and supplying the oxygen by nano-bubble oxygen rich water for cultivating the Matsutake Mushroom, instead of the conventional process of sterilization of the badge by hot steam over 120 .deg. C consuming over 8 hours and expensive ventilation system for supplying the fresh air for delivering the oxygen.

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

Science.gov (United States)

Lee, YoungJu; Won, Yuho; Kang, Kidoo

2015-04-01

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

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

International Nuclear Information System (INIS)

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

1985-09-01

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

Neutron area monitor with TLD pairs

International Nuclear Information System (INIS)

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

2011-11-01

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

Detection of narcotics with an immunoassay film badge

International Nuclear Information System (INIS)

Lukens, H.R.

1993-01-01

Efficient personnel performance, a major requirement for a safe nuclear industry, is jeopardized where personnel use narcotics. However, detection of narcotics at nuclear plants is a challenge. The unique specificity and sensitivity of an immunoassay has been implemented in the form of a small, dry immunoassay film badge (IFB) for the detection of vapors emitted by narcotics. The device is suitable as an area monitor, and its characteristics are suitable for use as a breath monitor for the detection of drug use

Centralized TLD service and record keeping in Canada

International Nuclear Information System (INIS)

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

1979-01-01

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

A TLD-based personal dosemeter system for air crew monitoring

International Nuclear Information System (INIS)

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

2003-01-01

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

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

International Nuclear Information System (INIS)

1982-04-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-07-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-06-01

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

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

International Nuclear Information System (INIS)

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

2014-01-01

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

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

International Nuclear Information System (INIS)

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

2014-08-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-08-15

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

Direct measurement of annual β dose using TLD on porcelain

International Nuclear Information System (INIS)

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

1999-01-01

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

Developmental roles of the BMP1/TLD metalloproteinases.

Science.gov (United States)

Ge, Gaoxiang; Greenspan, Daniel S

2006-03-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2008-02-15

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

Digital Badges for Staff Training: Motivate Employees to Learn with Micro-Credentials

Science.gov (United States)

Copenhaver, Kimberly; Pritchard, Liz

2017-01-01

Integrating micro-credentialing into employee training programs offers libraries an innovative and individualized way to recognize and certify learning and achievement. Digital badges provide a low-cost initiative to support learning benefiting both the individual and institution, offering evidence of skill development that transcends the library…

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

International Nuclear Information System (INIS)

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

1994-01-01

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

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

International Nuclear Information System (INIS)

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

1994-01-01

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

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

International Nuclear Information System (INIS)

Ekendahl, Daniela; Kapucianova, Michaela; Dufek, Vladimir

2014-01-01

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

Division of Radiological Protection : progress report, 1989-1991

International Nuclear Information System (INIS)

Gupta, B.L.; Nagarajan, P.S.; Bhatt, B.C.; Seethapathy, A.; Pradhan, A.S.; Vishwakarma, R.R.

1992-01-01

This report describes the work of the Division of Radiological Protection during 1989-91, for implementation of radiation safety in all institutions in the country using radiation sources for medical, industrial and research applications. It gives information about personnel monitoring using photographic film and TLD badges, neutron monitoring badges, dosimetric techniques developed, calibration techniques for high-dose irradiators, design and fabrication of special radiation protection instruments, advisory and licensing services, regulation and transport of radioactive materials, periodic protection survey, education and training related to radiation safety programmes. About 164 publications by the staff of this Division are listed. (author). 1 index., 1 tab

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

International Nuclear Information System (INIS)

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

1985-01-01

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

Environmental radiation measurements using TLD in and around AERE, Dhaka

International Nuclear Information System (INIS)

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

1986-01-01

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

Personal neutron monitoring using TLD albedo combined with etched tracks detector

Energy Technology Data Exchange (ETDEWEB)

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

2002-07-01

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

Nobels Nobels laureates photographed by Peter Badge

CERN Document Server

2008-01-01

A unique photographic record of all living Nobel laureates. In this handsome coffee-table book, photographer Peter Badge captures the likeness of every living Nobel laureate in a lasting black-and-white image -- more than 300 striking portraits in all. Brief biographical sketches accompanying the large-scale photographs pay homage to each laureate's singular contribution to science, literature or world peace. Bringing readers face-to-face with Nelson Mandela, Jimmy Carter, the Dalai Lama, James Watson, Gabriel García Márquez, Toni Morrison, Rita Levi-Montalcini, Linda Buck, and Paul Samuelson among many others, NOBELS offers an intimate and compelling look at well-known honorees as well as lesser-known recipients. A fascinating word/image tableau.

Calibration of TLD cards to beta ray spectra of 32P

International Nuclear Information System (INIS)

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

1994-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1998-12-31

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

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

International Nuclear Information System (INIS)

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

2006-01-01

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

Learning Analytics and Digital Badges: Potential Impact on Student Retention in Higher Education

Science.gov (United States)

Mah, Dana-Kristin

2016-01-01

Learning analytics and digital badges are emerging research fields in educational science. They both show promise for enhancing student retention in higher education, where withdrawals prior to degree completion remain at about 30% in Organisation for Economic Cooperation and Development member countries. This integrative review provides an…

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

International Nuclear Information System (INIS)

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

2000-01-01

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

Improvement of personal dosimetry - Digital pocket dosemeter

International Nuclear Information System (INIS)

Radalj, Z.; Cerovac, Z.; Cerovac, H.; Brumen, V.; Prlic, I.

1996-01-01

Physical dosimetric surveillance of professional groups working with various radiation sources is a regular procedure in Croatia, established almost 40 years ago. Data available point out that the majority of professionals under surveillance are those employed in medical facilities, most of them working with X-ray sources. Depending on the nature of professional activities, personnel occupationally exposed to radiation sources are obliged to wear either film badge, TLD or film+TLD badge. Unfortunately, due to the line of data processing, all standard dosemeters have the same disadvantage i.e. up to 40 days delay in dose reporting, regarding the time of actual exposure. The significance of such a delay raises in cases when radiation dose was received within the short time or when technical failure on the operating unit(s) is suspected. Bearing this in mind, the additional dosimetric monitoring becomes an imperative. Therefore, we decided to introduce a palette of digital pocket dosemeters, meant to be used in different workplaces in the radiation zone, each of them being adjusted to the specificities of a particular workplace

Experience of TLD personnel monitoring laboratory

International Nuclear Information System (INIS)

Jakhete, Prashant

2002-01-01

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

NRC TLD Direct Radiation Monitoring Network

International Nuclear Information System (INIS)

Struckmeyer, R.; McNamara, N.

1992-06-01

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

Perceptions and Uses of Digital Badges for Professional Learning Development in Higher Education

Science.gov (United States)

Dyjur, Patti; Lindstrom, Gabrielle

2017-01-01

Few instructors in higher education have completed a formal teaching program and, therefore, rely on informal professional development opportunities to enhance their teaching practice. Micro-credentialing in the form of digital badges is one way in which instructors can document their non-credit learning and accomplishments. This mixed methods…

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

Science.gov (United States)

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

2010-07-01

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

Indoor gamma radiation monitoring In Rawalpindi, Pakistan using TLD100

International Nuclear Information System (INIS)

Azam, Sana; Tufail, Muhammad; Sohail, Muhammad

2008-01-01

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

TLD Intercomparison in accelerators for radiotherapy in three Latin american countries

International Nuclear Information System (INIS)

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

1998-01-01

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

The study of new calibration features in the Harshaw TLD system

International Nuclear Information System (INIS)

Luo, L.Z.

2005-01-01

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

Environmental monitoring with TLD in Costa Rica

International Nuclear Information System (INIS)

Mora, P.; Mora, E.

2003-01-01

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

A scoping review towards the conceptualization of a digital Open Badges ecosystem in South Africa

CSIR Research Space (South Africa)

Motheeram, Preia

2016-11-01

Full Text Available relevant and rewarding pathways for learners. Open Badges can provide the infrastructure to facilitate this recognition of skills and achievements. In the absence of specific skills accreditation for informal skills and small scale competency development...

Improvements of RGD3 TLD reader

International Nuclear Information System (INIS)

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

1999-01-01

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

A LC-MS/MS method for the determination of BADGE-related and BFDGE-related compounds in canned fish food samples based on the formation of [M+NH(4)](+) aducts.

Science.gov (United States)

Míguez, J; Herrero, C; Quintás, I; Rodríguez, C; Gigosos, P G; Mariz, O C

2012-12-01

A new and simple liquid chromatography tandem mass-spectrometry method for the determination of different bisphenol A (BPA) derivatives such as bisphenol A diglycidyl ether (BADGE), bisphenol F diglycidyl ether (BFDGE) and their reaction products with water and hydrochloric acid in different fish food products was developed. The extraction procedure and the chromatographic conditions were optimised for complex food matrices such as fish products. Food samples were homogenised and extracted with a 1:1 solution of acetonitrile-hexane, the solvent was eliminated in a N(2) stream and the extract was reconstituted with 0.5mL of a 0.01M solution of ammonium formate. The sample solution obtained was directly measured by LC-MS/MS without any further purification under the developed conditions. The use of a mobile phase composed by ammonium formate-methanol in a binary gradient mode produced [M+NH(4)](+) aducts for the different BADGEs and BFDGEs. These aduct's fragmentations were employed for the LC-MS/MS quantification of BPA derivatives in canned fish samples. The results of the validation were appropriate: the method was linear for BADGE and its hydrolysed derivatives up to 1000μgkg(-1), for the remaining compounds linearity achieved up to 100μgkg(-1). Quantification limits were in the range 2-10μgkg(-1). RSD (intra and inter-day) was 6-12% and the recovery was comprised between 89% and 109%. Under the optimised conditions, the chromatographic separation was performed in 8min per sample. The method was applied to the determination of BADGE, BFDGE and their reaction products in different samples of canned fish from Spanish origin. Migration results obtained were in compliance with the EU regulations. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

International Nuclear Information System (INIS)

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

2009-01-01

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

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

Science.gov (United States)

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

2009-09-01

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

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market.

Science.gov (United States)

Uematsu, Y; Hirata, K; Suzuki, K; Iida, K; Saito, K

2001-02-01

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GC-MS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1 mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl anti BFDGE.HCl.H2O at a level of 1.5 mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.

Quality Assurance and Quality Control in TLD Measurement

International Nuclear Information System (INIS)

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

2008-01-01

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

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

International Nuclear Information System (INIS)

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

2017-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-05-15

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

Environmental Science and Engineering Merit Badges: An Exploratory Case Study of a Non-Formal Science Education Program and the U.S. Scientific and Engineering Practices

Science.gov (United States)

Vick, Matthew E.; Garvey, Michael P.

2016-01-01

The Boy Scouts of America's Environmental Science and Engineering merit badges are two of their over 120 merit badges offered as a part of a non-formal educational program to U.S. boys. The Scientific and Engineering Practices of the U.S. Next Generation Science Standards provide a vision of science education that includes integrating eight…

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

International Nuclear Information System (INIS)

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

1996-01-01

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

Performance tests of a CaSO4:Dy based thermoluminescence personal dosemeter

International Nuclear Information System (INIS)

Azorin, J.; Gutierrez, A.; Niewiadomski, T.

1986-01-01

In order to replace LiF commercial thermoluminescence dosemeters (TLDs) now used in personnel monitoring, we developed a TLD personnel monitoring badge based on pellets of CaSO 4 :Dy bound in pure KBr placed in plastic holders provided with 0.8 mm Pb filters to compensate for the energy dependence of CaSO 4 :Dy. Performance tests, based on the proposals of international standards for TLDs intended to be used as general deep tissue personal dosemeters, were done by developing the detailed test methods both for the tests required by the International Atomic Energy Agency (fading, linearity, effect of fluorescent light and sunlight and stability under standard climatic conditions) and to meet the requirements of the International Electrotechnical Commission (batch homogeneity, detection threshold, stability of zero point repeatibility and residual). Initial tests showed a high residual and an increase of inhomogeneity. However, these drawbacks were overcome by changing the annealing procedure and the readout conditions. Using these new conditions TLDs met all the requirements for personal dosemeters. (author)

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

International Nuclear Information System (INIS)

Duftschmid, K.E.; Strachotinsky, Ch.

1990-01-01

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

Microcomputer control of automated TLD reader

International Nuclear Information System (INIS)

Bjarland, Bert.

1979-10-01

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

Division of Radiological Protection progress report 1982-1988

International Nuclear Information System (INIS)

Gupta, B.L.; Bhat, R.M.; Narayan, G.R.

1989-01-01

This report describes the work of the Division of Radiological Protection during 2-88, for implementation of radiation safety in all institutions in the country using radiation sources for medical, industrial and research applications. It gives information about personnel monitoring using photographic film and TLD badges, neutron monitoring badges, dosimetric techniques developed, calibration facilities and maintenance of national standards for radiation and radioactivity, design and fabrication of special radiation protection instruments, development of coloured indicators for indentification of radiation sterilized medical products, advisory and licencing services, regulation and transport of radioactive materials, periodic protection survey, education and training related to radiation safety programmes. About 500 publications by the staff of this Division are listed. (author). 46 figs

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.

Carrying an anti-nuclear-power badge in the teaching profession. BVerwG, decision of January 25, 1990. Tragen einer Anti-Atomkraft-Plakette im Schuldienst. Urteil des BVerwG vom 25. 1. 1990

Energy Technology Data Exchange (ETDEWEB)

Anon,

1990-06-15

The carrying of an anti-nuclear-power badge by a teacher during school hours violates the order to practice reticence in political activities. At the beginning of 1977 some teachers, the plaintiff as well, carried anti-nuclear-power badges, i.e. a round badge with a stylized red sun on a yellow background with the inscription 'Nuclear power - No, thank you'. Following a general direction by the educational authorities, the headmistress forbade plaintiff on 4.11.77 to visibly carry this badge during lessons. This protest having been without success, action was brought with partial success at the Administrative and Higher Administrative Court. The Federal Administrative Court dismissed the case. (orig./HSCH).

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

International Nuclear Information System (INIS)

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

2014-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1999-07-01

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

The interpretability of doctor identification badges in UK hospitals: a survey of nurses and patients.

Science.gov (United States)

Hickerton, Bethan C; Fitzgerald, Daniel John; Perry, Elizabeth; De Bolla, Alan R

2014-07-01

Hospital badges have multiple important purposes, but their essential role remains the clear identification of the bearer, including their professional status. The modernisation of medical careers in the National Health Service has changed terminology dramatically, resulting in a plethora of new job titles emerging among both doctors and nurses. To determine whether the new or old terminology allowed clearer identification of medical doctors by patients and nurses. We replicated 11 identification badges used in the Royal Cornwall Hospital and Wrexham Maelor Hospital, both current and before the introduction of new medical training terminology. Data were collected from 114 patients and 67 nurses, by asking them to (1) identify which name badges represented doctors and (2) rank them in order of seniority. Only 11% of patients and 60% of nurses identified a 'Foundation Year 1 Trainee' as a qualified medical doctor. Indeed, only 'General Practice Vocational Trainee' and 'Consultant' were both readily identifiable as qualified doctors to both patients and nurses. Ranking was also a problem, with only 19% of patients and 45% of nurses able to correctly grade medical doctors using the current terminology. The old terminology allowed more accurate identification by nurses, with over 80% successfully ranking and marking the title appropriately. Current terminology is a source of confusion to both patients and members of the immediate medical care team, with nurses unable to correctly identify medical doctors. Our study indicates that a review of terminology is necessary to ensure patients, and staff, are able to communicate effectively. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

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

International Nuclear Information System (INIS)

Duftschmid, K.E.; Strachotinsky, Ch.

1978-04-01

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

The actual state and problems of radiation control in medical facilities

International Nuclear Information System (INIS)

Kaneko, Masao

1978-01-01

Utilization of radiation was started in university hospitals, but recently, the established general inspections come to be very popular among general hospitals. Numerous kinds of nuclides are utilized for a number of purposes in university hospitals, while the kinds of nuclides utilized in general hospitals are quite limited. Concerning radiation safety control, film badge method is most popular among personal exposure control methods, while the combinations of film badge and pocket chamber methods, and film badge and TLD methods are also adopted. In many general hospitals, however, the exposure control tools are not equipped. Many kinds of safety control devices are installed for general controls. The laws so far mainly regulated the standards of buildings and installations, but did not specify the standard for accommodating RI-administered patients, and the preventive measures to secondary exposure and pollution, which often causes careless control. Therefore, the preventive measures to secondary injuries are required. (Kobatake, H.)

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

International Nuclear Information System (INIS)

Valenta, J.; Ekendahl, D.

2005-01-01

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

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

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)

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

International Nuclear Information System (INIS)

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

2004-01-01

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

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

CERN Document Server

Kaskanov, G Y

2003-01-01

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

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

International Nuclear Information System (INIS)

Luo Huiyong; Wen Qinghua; Li Ruirong; Yu Enjian

2006-01-01

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

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

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

Directory of Open Access Journals (Sweden)

HosseiniAliabadi S. J.

2015-06-01

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

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.

Photon energy response of an aluminum oxide TLD environmental dosimeter

International Nuclear Information System (INIS)

Olsher, R.H.

1992-01-01

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

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

International Nuclear Information System (INIS)

Norhayati Abdullah; Taiman Kadni

2016-01-01

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

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

International Nuclear Information System (INIS)

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

2015-01-01

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

Meeting regulatory standards with BeO ceramic TLD

International Nuclear Information System (INIS)

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

1978-01-01

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

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

International Nuclear Information System (INIS)

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

2003-01-01

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

Determination of the TLD-100 physical parameters

International Nuclear Information System (INIS)

Paucar J, J.; Picon C, C.

1998-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2006-07-01

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

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

International Nuclear Information System (INIS)

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

2006-01-01

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

The Effect of Badges on the Engagement of Students with Special Educational Needs: A Case Study

Science.gov (United States)

Sitra, Ourania; Katsigiannakis, Vangelis; Karagiannidis, Charalampos; Mavropoulou, Sofia

2017-01-01

This paper addresses the perceived benefits from gamification in the context of special education. It presents the findings of a study evaluating the effects of a specific gamification element (badges) on the engagement of five students with special learning needs, through online courses developed on the Moodle Learning Management System (LMS).…

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

Science.gov (United States)

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

2014-01-01

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

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

Science.gov (United States)

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

2017-06-01

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

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

International Nuclear Information System (INIS)

Nariyama, N.

2000-01-01

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

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

International Nuclear Information System (INIS)

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

2014-01-01

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

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

International Nuclear Information System (INIS)

Struckmeyer, R.; McNamara, N.

1989-09-01

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

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

International Nuclear Information System (INIS)

Struckmeyer, R.; McNamara, N.

1988-09-01

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

Pupil's motivation in the 3. grades for required reading and The Reading Badge

OpenAIRE

Logar, Renata

2013-01-01

Reading is extremely important for pupils and their development. The pupil with reading habits riches his vocabulary and gaining knowledge. On the other hand the pupil through reading entry into the world of imagination and stories. Major role in motivating students to read have parents and teachers. In this graduation thesis I was interested in how third grade teachers motivate their pupils to read. In doing so, I was focused mainly to reading for required reading and The Reading Badge. ...

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

International Nuclear Information System (INIS)

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

2014-01-01

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

Access control system in Hamaoka Nuclear Power Station

International Nuclear Information System (INIS)

Kaneda, Hisashi; Shimura, Shigetaka; Suzuki, Katsuhiko; Kitazawa, Toshiichi

1983-01-01

The new computerized system has introduced to improve function of radiation protection for those who enter the radiation control area, by dealing with measurement of radiation dose, check of personal qualification, resistration of working condition and statistical treatment of these data. This system uses combined TLD, ''TL BADGE'', as a radiation detection sensor, instead of conventional pocket dosimeter and film badge. TL BADGE reading instrument are installed at the entrance to the control area and at working areas. The data of radiation dose, personal qualification etc. read by the reading instrument are transmitted directly to the computer system, which compiles and transacts these data. This system is consisted of three minicomputers, double memory files, CRTs for effective data search and display and floppy disks as a medium for registration, etc. Thus the computer system improves its reliability and the maintenanceability of data, being capable of automatical transaction of a great amount of data quickly. This report describes: Concept of using computer system, System outline, Measurement of radiation dose and Operational functions. (author)

A personnel TLD system with person identification

International Nuclear Information System (INIS)

Widell, C.O.

1974-01-01

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

Levels of doses to radiological workers in Ethiopia: 1977-1988

International Nuclear Information System (INIS)

Bayou, Teshome.

1991-01-01

During the period 1977 to 1988, a total of 10,494 Eastman Kodak type 2 film badges and 19,236 Vinten lithium fluoride thermoluminescence dosimeters (TLDS) were delivered to medical workers in Ethiopia of which 5,135 (48.93%) film badges and 19,177 (99.69%) TLDS were evaluated. The annual average occupational doses to the workers were estimated to be of 1.44 and 4.51 man-Sv with corresponding collective dose equivalents to 0.29 and 4.51 man-Sv respectively. Comparisons of doses to similar workers in different countries were compiled from the literature. Based on the TLD results and the 1977 International Commission on Radiological Protection (ICRP) risk coefficients it is estimated that the occurrence of extra fatal and non-fatal cancer cases is in the order of 74 per million radiological workers per year. The hereditary defects expected are 18 and 36 cases in the next two and in all future generations respectively. During these periods, the number of institutions monitored rose from 35 to 88 while the workers monitored increased from 100 to 450

Further characteristics important in the operation of ceramic BeO TLD

International Nuclear Information System (INIS)

Gammage, R.B.

1977-01-01

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

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

Science.gov (United States)

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

2017-09-01

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

TLD DRD dose discrepancy: role of beta radiation fields

International Nuclear Information System (INIS)

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

2014-01-01

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

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

International Nuclear Information System (INIS)

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

2005-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2004-07-01

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

Influences of scattering radiation in a TLD irradiation room, 2

International Nuclear Information System (INIS)

Suzuki, Osamu; Suwa, Shigeo

1985-01-01

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

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

International Nuclear Information System (INIS)

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

2007-01-01

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

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

Directory of Open Access Journals (Sweden)

Raffaele Liuzzi

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-01-22

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

Effects of the Boy Scouts of America Personal Fitness Merit Badge on Cardio-Metabolic Risk, Health Related Fitness and Physical Activity in Adolescent Boys.

Science.gov (United States)

Maxwell, Justin; Burns, Ryan D; Brusseau, Timothy A

2017-01-01

A growing number of adolescents are more sedentary and have fewer formal opportunities to participate in physical activity. With the mounting evidence that sedentary time has a negative impact on cardiometabolic profiles, health related fitness and physical activity, there is a pressing need to find an affordable adolescent physical activity intervention. One possible intervention that has been overlooked in the past is Boy Scouts of America. There are nearly 900,000 adolescent boys who participate in Boy Scouts in the United States. The purpose of this research study was to evaluate the effect of the Personal Fitness merit badge system on physical activity, health-related fitness, and cardio-metabolic blood profiles in Boy Scouts 11-17 years of age. Participants were fourteen (N = 14) Boy Scouts from the Great Salt Lake Council of the Boy Scouts of America who earned their Personal Fitness merit badge. Classes were held in the Spring of 2016 where boys received the information needed to obtain the merit badge and data were collected. Results from the related-samples Wilcoxon signed rank test showed that the median of differences between VO 2 peak pre-test and post-test scores were statistically significant ( p = 0.004). However, it also showed that the differences between the Pre-MetS (metabolic syndrome) and Post-MetS scores (p = 0.917), average steps taken per day ( p = 0.317), and BMI ( p = 0.419) were not statistically significant. In conclusion, the merit badge program had a positive impact on cardiovascular endurance, suggesting this program has potential to improve cardiovascular fitness and should be considered for boys participating in Boy Scouts.

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

Energy Technology Data Exchange (ETDEWEB)

Dijk, J.W.E. van

1998-07-01

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

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

International Nuclear Information System (INIS)

Dijk, J.W.E. van

1998-01-01

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

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

International Nuclear Information System (INIS)

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

2002-01-01

Full text: The Czech TLD QA network was established in 1997, as a part of the External Auditing Group (EAG) originated in 1995, in order to perform an independent quality audit in external beam therapy for two purposes: a) to unify the dose within radiotherapy departments, b) to impact state supervision. On basis of a good experience with this network in radiotherapy, new methods were developed to expand the network also to radiology in order to simplify the operation of state supervision. The TLD QA network in dental radiology has been brought into practice in 2001. Both the TLD audits performed in radiotherapy and radiology are realized via mailed dosimetry. In radiotherapy, two modes of the audit are used. Basic mode of TLD audit covers measurements under reference conditions, specifically beam calibration checks for all clinically used photon and electron beams. According to Czech regulations every beam must be checked in this way at least once during two years' period. Advanced mode consists of measurements under both reference and non- reference conditions using Leuven multi-purpose phantom for photon beams. It enables to check a substantial part of the treatment planning process inclusive of final dose realization of the planned radiotherapy. The radiotherapy centers are instructed to deliver absorbed dose of 2 Gy to the TLDs on central beam axis based on calculated treatment time or monitor units by their treatment planning system for a particular treatment set-up. In this way the TLD measured doses are compared with the calculated ones. Deviations of ±3% are considered acceptable for both basic and advanced modes of the audit, deviations up to ±6% are still tolerable, but new audit is repeated as soon as possible to solve the dosimetry problem. Deviations above ±6% leads immediately to investigation by EAG. There are 34 centers in the Czech Republic, which provide external beam radiotherapy. Since they must undergo the basic TLD audit regularly every

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

Energy Technology Data Exchange (ETDEWEB)

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

1990-01-01

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

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

International Nuclear Information System (INIS)

Nazaroh; Susetyo Trijoko; Sri Inang Sunaryati

2010-01-01

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

Ten years of a National Service of Dosimetric calibration at radiation protection

International Nuclear Information System (INIS)

Morales, J.A.; Jova, L.; Hernandez, E.; Campa, R.; Walwyn, G.

1996-01-01

Since 1986, the CPHR has offered a national service of calibration of dosimetric instruments at levels of radiation protection. The history of such a service is the chronology of efforts to reduce the uncertainties of the calibration process, expand the ranges of useful dose rates, and enhance the radiological safety when using the sources. The crowning of those efforts is the complement and start-up of the secondary la laboratory of dosimetric calibration (SLDC), which is currently a member of the IAEA/WHO. SLDC international network. As a result of this service, 256 instruments have been calibration and 867 personal dosimeters film badges and TLD and 72 environmental TLD dosimeters have been irradiated at known doses. The service rendered has benefited 62 national institutions which are users of ionizing radiations

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

Energy Technology Data Exchange (ETDEWEB)

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

2010-07-01

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

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

International Nuclear Information System (INIS)

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

2014-01-01

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

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

International Nuclear Information System (INIS)

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

1999-01-01

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

Dosimetric characteristics of a TLD dosemeter with extremities

International Nuclear Information System (INIS)

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

1999-01-01

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

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

International Nuclear Information System (INIS)

Regulla, D.F.; Drexeler, G.

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

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

International Nuclear Information System (INIS)

Kurnia, E; Oetami, H R; Mutiah

1996-01-01

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

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

International Nuclear Information System (INIS)

Hentschel, R; Mukherjee, B

2014-01-01

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

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

International Nuclear Information System (INIS)

Struckmeyer, R.; McNamara, N.

1988-06-01

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

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

International Nuclear Information System (INIS)

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

1979-01-01

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

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

International Nuclear Information System (INIS)

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

2005-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1994-07-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1994-08-01

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

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

International Nuclear Information System (INIS)

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

2001-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2011-07-01

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

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

International Nuclear Information System (INIS)

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

2012-01-01

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

Evaluation on the Radiation Exposure of Radiation Workers in Proton Therapy

International Nuclear Information System (INIS)

Lee, Seung Hyun; Jang, Yo Jong; Kim, Tae Yoon; Jeong, Do Hyung; Choi, Gye Suk

2012-01-01

Unlike the existing linear accelerator with photon, proton therapy produces a number of second radiation due to the kinds of nuclide including neutron that is produced from the interaction with matter, and more attention must be paid on the exposure level of radiation workers for this reason. Therefore, thermoluminescence dosimeter (TLD) that is being widely used to measure radiation was utilized to analyze the exposure level of the radiation workers and propose a basic data about the radiation exposure level during the proton therapy. The subjects were radiation workers who worked at the proton therapy center of National Cancer Center and TLD Badge was used to compare the measured data of exposure level. In order to check the dispersion of exposure dose on body parts from the second radiation coming out surrounding the beam line of proton, TLD (width and length: 3 mm each) was attached to on the body spots (lateral canthi, neck, nipples, umbilicus, back, wrists) and retained them for 8 working hours, and the average data was obtained after measuring them for 80 hours. Moreover, in order to look into the dispersion of spatial exposure in the treatment room, TLD was attached on the snout, PPS (Patient Positioning System), Pendant, block closet, DIPS (Digital Image Positioning System), Console, doors and measured its exposure dose level during the working hours per day. As a result of measuring exposure level of TLD Badge of radiation workers, quarterly average was 0.174 mSv, yearly average was 0.543 mSv, and after measuring the exposure level of body spots, it showed that the highest exposed body spot was neck and the lowest exposed body spot was back (the middle point of a line connecting both scapula superior angles). Investigation into the spatial exposure according to the workers' movement revealed that the exposure level was highest near the snout and as the distance becomes distant, it went lower. Even a small amount of exposure will eventually increase

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

CERN Document Server

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

2002-01-01

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

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

International Nuclear Information System (INIS)

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

1992-09-01

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

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

International Nuclear Information System (INIS)

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

2011-01-01

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

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

International Nuclear Information System (INIS)

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

2005-01-01

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

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

International Nuclear Information System (INIS)

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

2015-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-06-15

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

A Radiation Badge Survey for Family Members Living With Patients Treated With a 103Pd Permanent Breast Seed Implant

International Nuclear Information System (INIS)

Keller, Brian M.; Pignol, Jean-Philippe; Rakovitch, Eileen; Sankreacha, Raxa; O'Brien, Peter

2008-01-01

Purpose: Sixty-seven patients with early-stage breast cancer were treated in a Phase I/II clinical trial using a 103 Pd permanent breast seed implant as adjuvant radiotherapy after breast-conserving surgery. We report the dose received by family members living with these patients and compare measured doses with theoretical worst-case scenario estimates. Methods and Materials: Exposure-rate measurements were taken at 1 m from the patient by using a calibrated low-energy survey meter. Landauer (Landauer Inc., Glenwood, IL) Luxel badges, with sensitivity of 0.01 mSv, were given to family members to wear after the implantation. Badge readings for 33 spouses and 28 other family members were used to estimate effective doses, and these were compared with theory. Results: Average preimplantation planning target volume from computed tomography was 50.3 ml (range, 18.0-96.7 ml), and average preimplantation distance between the skin and the most anterior planning target volume margin was 0.57 cm. The average maximum exposure rate was measured to be 2.4 ± 1.1 mR/h, and average measured dose to a spouse was 0.99 ± 1.0 mSv. The calculated exposure rates and spousal doses using preimplantation computed tomography scan data overestimated those measured. Average measured family member dose (excluding spouses) was 0.20 ± 0.58 mSv. Conclusions: Based on measured and calculated spousal doses, a permanent breast seed implant using 103 Pd is safe for the public. However, it is recommended that extra precautions in the way of a breast patch be used when patients with an implant will be in the vicinity of toddlers or pregnant women

Comparing Digital Badges-and-Points with Classroom Token Systems: Effects on Elementary School ESL Students' Classroom Behavior and English Learning

Science.gov (United States)

Homer, Ryan; Hew, Khe Foon; Tan, Cheng Yong

2018-01-01

This paper reports the findings of a field experiment that gamified the classroom experience of elementary school ESL students by implementing digital badges-and-points which students could earn by achieving specific behavioral and learning goals. Altogether, 120 children in eight different classes participated in this study. Four of the classes…

Measurement of exposure dose rate by TLD in 60Co garden

International Nuclear Information System (INIS)

Fan Chengfang; Li Pinfang; Wu Maoliang; Zhao Quan

1987-01-01

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

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

International Nuclear Information System (INIS)

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

2011-01-01

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

Dosimetric evaluation of the staff working in a PET/CT department

International Nuclear Information System (INIS)

Dalianis, K.; Malamitsi, J.; Gogou, L.; Pagou, M.; Efthimiadou, R.; Andreou, J.; Louizi, A.; Georgiou, E.

2006-01-01

The dosimetric literature data concerning the medical personnel working in positron emission tomography/computed tomography (PET/CT) departments are limited. Therefore, we measured the radiation dose of the staff working in the first PET/CT department in Greece at the Diagnostic and Therapeutic Center of Athens HYGEIA-Harvard Medical International. As, for the time being, only 2-deoxy-2-[ 18 F]fluoro-d-glucose (FDG) PET studies are performed, radiation dose measurements concern those derived from dispensing of the radiopharmaceutical as well as from the patients undergoing FDG-PET imaging. Our aim is to develop more effective protective measures against radionuclide exposure. To estimate the effective dose from external exposure, all seven members of the staff (two nurses, two medical physicists, two technologists, one secretary) had TLD badges worn at the upper pocket of their overall, TLD rings on the right hand and digital dosimeters at their upper side pocket. In addition, isodose curves were measured with thermoluminescence detectors for distances of 20, 50, 70 and 100 cm away from patients who had been injected with 18 F-FDG. Dose values of the PET/CT staff were measured with digital detectors, TLD badges and TLD rings over the first 8 months for a total of 160 working days of the department's operation, consisting of a workload of about 10-15 patients/week who received 250-420 MBq of 18 F-FDG each. Whole - body collective doses and hand doses for the staff were the following: Nurse no. 1 received 1.6 mSv as a whole body dose and 2,1 as a hand dose, Nurse no. 2 received 1.9 and 2.4 mSv respectively. For medical physicist no. 1 the dose values were 1.45 mSv whole body and 1.7 mSv hand dose, for medical physicist no. 2 1.67 mSv wholebody dose and 1.55 mSv hand dose and for technologists no. 1 and no. 2 the whole body doses were 0.7 and 0.64 mSv respectively. Lastly, the secretary received 0.1 mSv whole body dose. These preliminary data have shown that the dose

Dosimetric evaluation of the staff working in a PET/CT department

Energy Technology Data Exchange (ETDEWEB)

Dalianis, K. [Department of PET/CT, Diagnostic and Therapeutic Center of Athens Hygeia-Harvard Medical International, Erythrau Stavrou 4, 5123 Athens (Greece)]. E-mail: k.dalianis@hygeia.gr; Malamitsi, J. [Department of PET/CT, Diagnostic and Therapeutic Center of Athens Hygeia-Harvard Medical International, Erythrau Stavrou 4, 5123 Athens (Greece); Gogou, L. [Department of PET/CT, Diagnostic and Therapeutic Center of Athens Hygeia-Harvard Medical International, Erythrau Stavrou 4, 5123 Athens (Greece); Pagou, M. [Department of PET/CT, Diagnostic and Therapeutic Center of Athens Hygeia-Harvard Medical International, Erythrau Stavrou 4, 5123 Athens (Greece); Efthimiadou, R. [Department of PET/CT, Diagnostic and Therapeutic Center of Athens Hygeia-Harvard Medical International, Erythrau Stavrou 4, 5123 Athens (Greece); Andreou, J. [Department of PET/CT, Diagnostic and Therapeutic Center of Athens Hygeia-Harvard Medical International, Erythrau Stavrou 4, 5123 Athens (Greece); Louizi, A. [Department of Medical Physics Medical School University of Athens, Athens (Greece); Georgiou, E. [Department of Medical Physics Medical School University of Athens, Athens (Greece)

2006-12-20

The dosimetric literature data concerning the medical personnel working in positron emission tomography/computed tomography (PET/CT) departments are limited. Therefore, we measured the radiation dose of the staff working in the first PET/CT department in Greece at the Diagnostic and Therapeutic Center of Athens HYGEIA-Harvard Medical International. As, for the time being, only 2-deoxy-2-[{sup 18}F]fluoro-d-glucose (FDG) PET studies are performed, radiation dose measurements concern those derived from dispensing of the radiopharmaceutical as well as from the patients undergoing FDG-PET imaging. Our aim is to develop more effective protective measures against radionuclide exposure. To estimate the effective dose from external exposure, all seven members of the staff (two nurses, two medical physicists, two technologists, one secretary) had TLD badges worn at the upper pocket of their overall, TLD rings on the right hand and digital dosimeters at their upper side pocket. In addition, isodose curves were measured with thermoluminescence detectors for distances of 20, 50, 70 and 100 cm away from patients who had been injected with {sup 18}F-FDG. Dose values of the PET/CT staff were measured with digital detectors, TLD badges and TLD rings over the first 8 months for a total of 160 working days of the department's operation, consisting of a workload of about 10-15 patients/week who received 250-420 MBq of {sup 18}F-FDG each. Whole - body collective doses and hand doses for the staff were the following: Nurse no. 1 received 1.6 mSv as a whole body dose and 2,1 as a hand dose, Nurse no. 2 received 1.9 and 2.4 mSv respectively. For medical physicist no. 1 the dose values were 1.45 mSv whole body and 1.7 mSv hand dose, for medical physicist no. 2 1.67 mSv wholebody dose and 1.55 mSv hand dose and for technologists no. 1 and no. 2 the whole body doses were 0.7 and 0.64 mSv respectively. Lastly, the secretary received 0.1 mSv whole body dose. These preliminary data have

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

International Nuclear Information System (INIS)

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

1999-01-01

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

Automating the personnel dosimeter monitoring program

International Nuclear Information System (INIS)

Compston, M.W.

1982-12-01

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

Results of the IAEA/RCA personal dosemeter intercomparison

Energy Technology Data Exchange (ETDEWEB)

Tsujimura, Norio; Momose, Takumaro; Hayashi, Naomi [Environment and Safety Division, Tokai Works, Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan)

2000-06-01

The intercomparison of personal dosemeters for photon was carried out between 1990 and 1996 as part of the IAEA/RCA 'strengthening of radiation protection infrastructure' project. Japan Nuclear Cycle Development Institute participated in the intercomparison as one of the in-house personal dosimetry service organizations in Japan and also served the host irradiating laboratory. This report summarizes the dose evaluation results obtained from the JNC-TLD badges in the past four intercomparison programs. In the latest intercomparison the evaluated doses agreed to the reference doses with an accuracy of 10%. (author)

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

International Nuclear Information System (INIS)

Pradhan, A.S.; Hoffmann, W.

1986-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1995-12-01

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

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

International Nuclear Information System (INIS)

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

2010-01-01

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

Determination of BPA, BPB, BPF, BADGE and BFDGE in canned energy drinks by molecularly imprinted polymer cleaning up and UPLC with fluorescence detection.

Science.gov (United States)

Gallo, Pasquale; Di Marco Pisciottano, Ilaria; Esposito, Francesco; Fasano, Evelina; Scognamiglio, Gelsomina; Mita, Gustavo Damiano; Cirillo, Teresa

2017-04-01

A new method for simultaneous determination of five bisphenols in canned energy drinks by UPLC with fluorescence detection, after clean up on molecularly imprinted polymers, is herein described. The method was validated at two concentration levels, calculating trueness, repeatability and within-laboratory reproducibility, specificity, linearity of detector response, the limits of quantifications and the limits of detection for each bisphenol. The method is specific, reliable and very sensitive, allowing for determination of bisphenol F diglycidyl ether (BFDGE), bisphenol A (BPA), bisphenol B (BPB), bisphenol F (BPF) and bisphenol A diglycidyl ether (BADGE) down to 0.50ng/mL; it was employed to determine contamination levels from these bisphenols in forty energy drinks of different brands, collected from the market in Naples. BPA was detected in 17 out of 40 samples (42.5%); in some energy drinks also BPF, BADGE and BFDGE were determined. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-12-15

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

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

International Nuclear Information System (INIS)

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

2015-01-01

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

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

International Nuclear Information System (INIS)

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

2006-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-07-01

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

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

International Nuclear Information System (INIS)

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

2013-01-01

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

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

International Nuclear Information System (INIS)

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

1997-01-01

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

TLD system for the monitoring of the environmental radioactivity

International Nuclear Information System (INIS)

Stochioiu, Ana; Sahagia, Maria; Tudor, Ion

2008-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2006-07-01

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

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

International Nuclear Information System (INIS)

Shiragai, A.

1977-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2006-07-01

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

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

International Nuclear Information System (INIS)

Knipe, A.D.

1977-01-01

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

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

International Nuclear Information System (INIS)

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

2008-01-01

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

Personal neutron diode dosemeter

International Nuclear Information System (INIS)

Barthe, J.; Lahaye, T.; Moiseev, T.; Portal, G.

1993-01-01

The control and management of neutron doses, received by workers in nuclear power or research facilities, requires a knowledge of cumulated dose equivalent or dose equivalent rate in real time. Individual dosemeters so far developed for this purpose are scarce and not very satisfactory. Passive dosemeters such as TLD systems based on the albedo effect, nuclear emulsions or solid track detectors, do not give sufficiently accurate measurements. Furthermore, the increase in the quality factor and the more restrictive new ICRP recommendations diminish the maximum admissible threshold making currently used systems obsolete. Other than bubble dosemeter systems, based on thermodynamic effects of a superheated gel, no simple electronic device is available at the present time. The development of diode based dosimetric gamma badges, having a size similar to that of credit cards, has stimulated us to design and develop a personal neutron dosemeter based on a double diode system. The results obtained are very encouraging and practical models should become available in the near future. (author)

Design of a new two element OSLD Badge for eye lens monitoring

International Nuclear Information System (INIS)

Kulkarni, M.S.; Munish Kumar; Ratna, P.; Babu, D.A.R.; Muthe, K.P.; Biju, K.; Sunil, C.; Sharma, D.N.

2014-01-01

Normally the dose to the vicinity of the eye is received by the occupational radiation workers who handle radioisotopes or doctors who perform interventional radiographic procedures. The Eye dosimeters provide an estimate of the radiation dose to the lens of the eye. In the recent ICRP-2011 recommendations, the equivalent dose limit for the lens of the eye has been reduced from 150 mSv in a year to 20 mSv in a year for all the occupational workers. To ensure that the dose limit for the eye lens does not exceed the prescribed dose limits, various eye lens dosimeters have been designed and are being used internationally. All these eye dosimeters consist of one natural LiF based thermoluminescence dosimeter (TLD) element sealed in a plastic holder. The design of the eye dosimeter and place of wear (near the eye) plays an important role in correct estimation of the dose to the lens of the eye. It is generally seen that the eye dosimeter when worn with the head strap on the forehead near the eye, the dose the element receives can be easily correlated to the eye dose. This paper presents the design of a new Eye lens dosimeter based on optically stimulated luminescence (OSL) detectors for its possible use by the occupational workers covering the medical, industrial and nuclear facilities for assessing the Hp(3)

SSDL personel dosimetry system: migration from a client - server system into a web-based system

International Nuclear Information System (INIS)

Maizura Ibrahim; Rosnah Shariff; Ahmad Bazlie Abdul Kadir; John Konsoh Sangau; Mohd Amin Sharifuldin Salleh; Taiman Kadni; Noriah Mod Ali

2007-01-01

Personnel Dosimetry System has been used by the Secondary Standard Dosimetry Laboratory (SSDL), Nuclear Malaysia since ten years ago. The system is a computerized database system with a client-server concept. This system has been used by Film Badge Laboratory, SSDL to record details of clients, calculation of Film Badge dosage, management of radiation workers data's, generating of dosage report, retrieval of statistical reports regarding film badge usage for the purpose of reporting to monitoring bodies such as Atomic Energy Licensing Board (AELB), Ministry of Health and others. But, due to technical problems that frequently occurs, the system is going to be replaced by a newly developed web- based system called e-SSDL. This paper describe the problems that regularly occurs in the previous system, explains how the process of replacing the client-server system with a web-based system is done and the differences between the previous and current system. This paper will also present details architecture of the new system and the new process introduced in processing film badges. (Author)

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

International Nuclear Information System (INIS)

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

1999-01-01

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

New advanced TLD system for space dosimetry

International Nuclear Information System (INIS)

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

1983-10-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2004-07-01

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

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

International Nuclear Information System (INIS)

Azorin, Juan; Gutierrez, Alicia; Furetta, Claudio

1989-01-01

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

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

International Nuclear Information System (INIS)

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

2006-01-01

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

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

International Nuclear Information System (INIS)

Piesch, E.; Burgkhardt, B.

1988-03-01

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

The application of artificial neural networks to TLD dose algorithm

International Nuclear Information System (INIS)

Moscovitch, M.

1997-01-01

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

Unfolding neutron spectra with BS-TLD system using genetic algorithms

Energy Technology Data Exchange (ETDEWEB)

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

2011-07-01

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

Unfolding neutron spectra with BS-TLD system using genetic algorithms

International Nuclear Information System (INIS)

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

2011-01-01

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

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

International Nuclear Information System (INIS)

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

1981-01-01

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

Brazilian two-component TLD albedo neutron individual monitoring system

Energy Technology Data Exchange (ETDEWEB)

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

2010-12-15

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

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

International Nuclear Information System (INIS)

Rassow, J.

1984-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2007-07-01

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

Dosimetry and LET spectrometry in C 290 MeV/n and Ne 400 MeV/n HIMAC ion beam by different TLD's, TED based LET spectrometers, and Si energy-deposition spectrometer

International Nuclear Information System (INIS)

Spurny, F.; Brabcova, K.; Jadrnickova, I.; Uchihori, Y.; Kitamura, H.; Yasuda, N.; Molokanov, A. G.

2009-01-01

The sets of track etched detectors based (TED) spectrometer's of the linear energy transfer (LET) have been, together with two types of thermoluminescent detectors (TLD)and MDU- Liulin energy deposition spectrometer exposed in the C 290 MeV/n and Ne 400 MeV/n ion beams at the HlMAC installation at NIRS, Chiba, Japan. The experiment has been performed in the frame of NPI project 20P241 agreed by HlMAC P AC at the beginning of 2008 year. Up to now, moxstle only results obtained in C-ion beam have been treated and analyzed. Sets of TED spectrometer's and TLD detectors have been exposed in 19 depths in the C-ion beam with expected LET values of primary particles from 13 keV/μm in water, through the Bragg peak area up to two depth behind the Bragg peak. The contribution of fragments to total number of events, and to the energy absorbed in Si has been determined, when possible separately for different fragments. In all cases also total contribution of fragments (and other secondary particles) to the total number of energy deposition events and to the absorbed dose has been estimated. LET and energy deposition spectra obtained will be compared together , a good agreement of data has bee stated. Some of results have been also compared with those obtained by calculation by means of PHITS code. (authors)

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

CERN Document Server

Lagutin, I G; Ershova, N N

2003-01-01

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

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

International Nuclear Information System (INIS)

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

2013-01-01

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

Nuclear accident dosimetry measurements at the fourth IAEA intercomparison, Harwell, United Kingdom, April 1975

International Nuclear Information System (INIS)

Majborn, B.

1975-11-01

During the fourth IAEA intercomparison at Harwell, teams from several countries compared their systems for assessing doses in criticality accidents. The dosimeters were exposed to mixed pulses of neutron and gamma radiation produced by the VIPER reactor at AWRE, Aldermaston. Risoe participated in this intercomparison with the routine personnel dosimeters employed in 'criticality areas' at Risoe. These include the UKAEA criticality dosimeter for the measurement of neutron doses and the Risoe TLD badge for the measurement of gamma doses. The final results of the Risoe measurements are presented in this report in a form designed for ease of comparison with results of other pparticipants. (author)

Thermoluminescent dosimetry and assessment of personal dose

International Nuclear Information System (INIS)

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

1982-01-01

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

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

Science.gov (United States)

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

1984-05-01

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

Estimation of uncertainty in TLD calibration

International Nuclear Information System (INIS)

Hasabelrasoul, H. A.

2013-07-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-10-15

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

Radiation hazard control report

International Nuclear Information System (INIS)

Morishima, Hiroshige; Koga, Taeko; Hisanaga, Saemi; Miki, Ryota; Kawai, Hiroshi; Aoki, Yutaka; Sone, Koji; Okada, Hirokazu

1990-01-01

The report describes the radiation hazard control activities performed at the Atomic Energy Research Institute of Kinki University, Japan, during the one-year period from April 1989 to March 1990. Personal radiation hazard control is outlined first focusing on results of physical examination and data of personal exposure dose equivalent. Radiation control in laboratory is then described. Dose equivalent at various places is discussed on the basis of monthly total dose equivalent measured on film badges, measurements made by TLD, and observations made through a continuous radiations monitoring system. The concentration of radiations in air and water is discussed focusing on their measured concentrations in air at the air outlets of tracer/accelerator facilities, and radioactivity in waste water sampled in the reactor facilities and tracer/accelerator facilities. Another discussion is made on the surface contamination density over the floors, draft systems, sink surface, etc. Concerning outdoor radiation hazard control, furthermore, TLD measurements of environmental gamma-rays, data on total gamma-ray radioactivity in environmental samples, and analysis of gamma-ray emitting nuclides in environmental samples are described and discussed. (N.K.)

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

International Nuclear Information System (INIS)

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

2016-01-01

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

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

International Nuclear Information System (INIS)

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

2004-01-01

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

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

International Nuclear Information System (INIS)

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

2005-01-01

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

Calibration of the indium foil used for criticality accident dosimetry in the UCC-ND employee identification badge

International Nuclear Information System (INIS)

Ryan, M.T.; Butler, H.M.; Gupton, E.D.; Sims, C.S.

1982-05-01

The UCC-ND Employee Identification Badge contains an indium foil disc that is intended for use as a dosimetry screening device in the event of a criticality accident. While it is recognized that indium is not a precise mixed neutron-gamma dosimeter, its activation by neutrons provides adequate means for separating potentially exposed persons into three groups. These groups are: (1) personnel exposed below annual dose limits, (2) personnel exposed above annual dose limits but below 25 rem, and (3) personnel exposed above 25 rem. This screening procedure is designed to facilitate dosimeter processing in order to meet regulatory reporting requirements. A quick method of interpreting induced activity measurements is presented and discussed

Development and evaluation of a new baDge/filter for thermoluminescent monitoring with CaSO4: Dy/PTFE

International Nuclear Information System (INIS)

Campos, Vicente de Paula

2005-01-01

Calcium Sulfate (CaSO 4 :Dy) phosphor Thermoluminescent Dosimeter (TLD) has been used by the Instituto de Pesquisas Energeticas e Nucleares (IPEN), SP, Brazil since 70's and 80's, due to important work of its researchers and collaborators. This phosphor advantages, beside the fact that it is produced by IPEN itself, begin to be more required and its disadvantages have became more apparent, in a global market more and more competitive. This phosphors was used primarily in environmental and area monitoring at IPEN facilities and in a few external institutions, once it presents more sensibility than other phosphors, like LiF:Mg. Its mainly disadvantage is a strong energetic dependence response to ionizing radiation, which must be corrected for its application in every radiation field. This phosphor has been used inside a badge which is an adaptation from photographic film badges used in the past. This badge permits a reasonable correction in the energetic dependence, only for orthogonal beam incidence. With the objective of improve the performance and reduce the energetic dependence on any incidence angle, reducing the dose measurement uncertainty too, this work presents a study on a new badge, with a new filter geometry, and its performance was compared to the actual dosimeter in use, with significant improve on results. Gamma irradiations of 60 Co and x-rays of 25,1; 33; 37,3 and 82,1 keV, on incidence angles of 0 deg, 30 deg, 45 deg and 90 deg were done at facility conditions of IPEN. Semi-empirical computational simulation using finite differences in three dimensions were done. The results pointed out the best filter thickness and width for initiate the prototype production, in order to optimize the correction on energetic dependence on irradiation of photons of 33, 48, 118 and 1250 keV energies under many incidence angles. (author)

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

International Nuclear Information System (INIS)

Yasuda, Hiroshi

2001-01-01

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

Performance analysis of the TNO TLD individual monitoring service

International Nuclear Information System (INIS)

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

1990-01-01

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

Measurement error in longitudinal film badge data

International Nuclear Information System (INIS)

Marsh, J.L.

2002-04-01

The classical measurement error model is that of a simple linear regression with unobservable variables. Information about the covariates is available only through error-prone measurements, usually with an additive structure. Ignoring errors has been shown to result in biased regression coefficients, reduced power of hypothesis tests and increased variability of parameter estimates. Radiation is known to be a causal factor for certain types of leukaemia. This link is mainly substantiated by the Atomic Bomb Survivor study, the Ankylosing Spondylitis Patients study, and studies of various other patients irradiated for therapeutic purposes. The carcinogenic relationship is believed to be a linear or quadratic function of dose but the risk estimates differ widely for the different studies. Previous cohort studies of the Sellafield workforce have used the cumulative annual exposure data for their risk estimates. The current 1:4 matched case-control study also uses the individual worker's film badge data, the majority of which has been unavailable in computerised form. The results from the 1:4 matched (on dates of birth and employment, sex and industrial status) case-control study are compared and contrasted with those for a 1:4 nested (within the worker cohort and matched on the same factors) case-control study using annual doses. The data consist of 186 cases and 744 controls from the work forces of four BNFL sites: Springfields, Sellafield, Capenhurst and Chapelcross. Initial logistic regressions turned up some surprising contradictory results which led to a re-sampling of Sellafield mortality controls without the date of employment matching factor. It is suggested that over matching is the cause of the contradictory results. Comparisons of the two measurements of radiation exposure suggest a strongly linear relationship with non-Normal errors. A method has been developed using the technique of Regression Calibration to deal with these in a case-control study context

Environmental monitoring system with TLD

International Nuclear Information System (INIS)

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

2006-01-01

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

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

International Nuclear Information System (INIS)

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

2000-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-08-15

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

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

International Nuclear Information System (INIS)

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

2007-01-01

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

Performing personnel dosimetry investigations and records quality assurance

International Nuclear Information System (INIS)

Perle, S.C.

2002-01-01

Radiation Safety Officers (RSOs) sometimes face situations in which personnel dosimetry estimates are required after dosimeters issued to radiation workers (film or TLD badges, extremity dosimeters, etc.) are lost or damaged before processing. This article was prepared to help those involved with personnel dosimetry investigations became aquatinted with this process. A factor that contributes to the anxiety of those unfamiliar with dosimetry investigations is the lack of published guidance available in this subject. More printed resources are needed to help radiation safety professionals familiarize themselves and understand personnel dosimetry investigations. Topics discussed in this presentation include the justification of performing dosimetry investigations, recommendations on how to perform them and the advantages of performing such investigations

Networked National Occupational Dose Registry System (NODRS)

International Nuclear Information System (INIS)

Sapra, B.K.

2016-01-01

Recording of occupational doses received by radiation workers during their working life is a mandatory aspect of radiation protection. Maintaining of life-time dose data of these radiation workers is also necessary for (i) ensuring and reviewing radiation safety of workers, (ii) certification and other legal purposes, and (iii) for statistical analysis and epidemiological studies. Centralized dose records are being maintained by BARC since the inception of Directorate of Radiation Protection in late sixties. The dose records were computerized since 1975 and the systems were upgraded from time to time. The requirement of personnel data information was made a pre-requisite for allotment of personnel number to new persons for TLD Badge services since 1992

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

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

International Nuclear Information System (INIS)

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

2003-01-01

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

Australian participation in international intercomparisons of environmental dosemeters

International Nuclear Information System (INIS)

Boas, J.F.; David, R.C.; Jones, J.

2002-01-01

The Environmental Measurements Laboratory of the U.S. Department of Energy has conducted international intercomparisons of environmental dosemeters at regular intervals since 1974. This paper reports the results obtained in the 10th and 11th intercomparisons by JFB and JGY at the Australian Radiation Laboratory (in 1992 and 1996 respectively) and in the 12th intercomparison by JFB and DRCT at the Australian Radiation Protection and Nuclear Safety Agency and by JGY and JJ at Australian Radiation Serviceces during 2000 and 2001. The ARL/ARPANSA measurements used a simple dosemeter holder containing two CaSO 4 :Dy impregnated Teflon discs, one unshielded and the other shielded by approximately 2.4 mm of Cu. The ARS measurements used a commercially available TLD badge case containing a CaSO 4 :Dy impregnated Teflon card. The commercial badge case was not symmetrical in design. The filtration in the front and rear sections of the commercial badge case varied from an open area to an area shielded by copper, tin and cadmium. The results obtained were generally within ±15% of the reference values measured by EML using high-pressure ionisation chambers for dosemeters exposed hi the field to environmental radiation and for dosemeters given a single exposure to 137 Cs or 241 Am at EML or an associated laboratory. Similar agreement was obtained for dosemeters exposed in the field and also given a single exposure to 137 Cs radiation. In order to obtain this measure of agreement, the dosemeters were individually calibrated and the readouts corrected for fading. Copyright (2002) Australasian Radiation Protection Society Inc

Occupational exposure from external radiation used in medical practices in Pakistan by film badge dosimetry

International Nuclear Information System (INIS)

Jabeen, A.; Munir, M.; Khalil, A.; Masood, M.; Akhter, P.

2010-01-01

Occupational exposure data of workers due to external sources of radiation in various medical practices such as nuclear medicine (NM), radiotherapy and diagnostic radiology (DR) in Pakistan were collected and analysed. Whole-body doses of workers were measured by film badge dosimetry technique during 2003-2007. Annual average effective dose in NM, radio-therapy and DR varied in the range of 1.39-1.80, 1.05-1.45 and 1.22-1.71 mSv, respectively, during 2003-2007. These values are quite low and well below the annual limit of 20 mSv averaged over a period of 5 consecutive years. Nobody received the radiation dose >50 mSv in any single year over a period of 5 consecutive years; therefore, no overexposure case has been detected. Decreasing trend of annual average dose values in aforementioned categories of work during 2003-2007 indicates the improvement of radiation protection status in medical field in Pakistan. (authors)

A critical review of an extremity monitoring program at the Instituto de Engenharia Nuclear in Brazil

International Nuclear Information System (INIS)

Fajardo, Patricia Wieland; Rosa, Luiz Antonio Ribeiro da

1993-01-01

Eventually the cyclotron of the Instituto de Engenharia Nuclear (IEN) may need maintenance; Its components are made of copper and they become highly activated after irradiations producing extensive 65 Zn sources. The individual monitoring of the maintenance workers is based on film badges and TLD rings. Both systems are calibrated in terms of 'Photon Dose Equivalent' and the extremity dosemeter is not able to discriminate the gamma and beta contributions to the total dose. Conservatively, it was possible to estimate, using another extremity dosemeter, that beta doses received by the workers' hands are three times higher than the gamma doses. Considering this result, and the ring TL responses, it was possible to estimate Hp(0.07), in the case of the hands, for all the IEN cyclotron maintenance workers, since 1983. The results show that Hp(0.07) values are about 2.88 times higher than the previous reported extremity doses in mSv. (author)

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

International Nuclear Information System (INIS)

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

2013-01-01

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

Measurement of the external doses at low and high exposures by Agfa personal monitoring film, FD-III-B badge

International Nuclear Information System (INIS)

Mihai, F.; Stochioiu, A.; Bercea, S.; Udup, E.; Tudor, I.

2008-01-01

Full text: A growing number of papers report occupational exposure monitoring by different dosemeter devices. Researches into improvement of the personal dosemeter systems are encouraged. Dose measurement and especially skin dose measurement, are therefore increasingly important. Methods and acceptable dosemeter are not clearly defined and differ from a dosimetry laboratory to other depending on their specifically work procedure and type of dosemeter utilized. Taking into account the characteristic of the work place (industry, research, medical application) dosemeter have to cover a large dose range. The dose assessment problems are manly in low doses range (under 0.2 mSv) and higher doses range. For example, typical for radiation oncology and nuclear accident dosimetry the dose ranges are on the order of 2-70 Gy and 0.1-5 Gy. This work presents the performance of the Agfa personal monitoring film, badge FD-III-B type used in the most of the occupational exposure monitoring from Romania. The FD-III-B dosimeter, manufactured in Romania, is used for monitoring personnel working in radioactive environment - the photodosimetric method is the one of the most reliable method presenting the advantage that the film may be considered as master probe over 30 year and may be utilized during litigation. The dosimeter contains metallic filters of Al, Cu, Pb with different thicknesses, a plastic filter and a open window. The badge FD-III-B is a class B dosimeter according to the dose range and an indices 3 dosimeter from energy range of the radiations in conformity with Romanian Standard in force. Film Agfa 'personal monitoring', tacked in this experiment, consists of a low speed film (D2) and a very sensitive film (D10) designed for recording X-ray, gamma and beta radiation over the doses range 0.1 mSv to 1 Sv. The experiments have been effectuated at different background optical density (base fog) of the films and at different sources of radiation: 13 :7Cs, 60 Co and 24 : 1 Am

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

Energy Technology Data Exchange (ETDEWEB)

Sagastibelza Chivite, F

1980-07-01

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

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

International Nuclear Information System (INIS)

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

2009-10-01

Properties of LiF:Mg,Cu,P+PTFE dosemeters developed at ININ have been investigated in order to evaluate their performance compared to those of equivalent commercial dosemeters. In this work both LiF:Mg,Cu,P+PTFE and TLD-100H pellets were exposed to low fluence 3 MeV protons and to low dose gamma radiation to evaluate experimental proton/gamma efficiencies. Gamma irradiation was performed using the Vic krad irradiator at ININ at varying doses between 25 and 500 mGy. For proton irradiation the Tandem Van de Graaff accelerator at ININ was used. Dosemeters were placed on a holder inside a scattering chamber where protons impinge on a gold target and scatter in all directions. The holder allows for several angular positions so that dosemeters receive proton fluence between 10 6 and 10 1 0 p/cm 2 . Experimental efficiency values found for LiF:Mg,Cu,P+PTFE and TLD-100H were 0.18 +- 03 and 0.23 +- 0.03, respectively. These results allow to confirm the reliability of the dosemeters developed at ININ. (Author)

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

International Nuclear Information System (INIS)

Derakhshan, Sh.

2004-01-01

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

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

International Nuclear Information System (INIS)

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

1987-01-01

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

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

NARCIS (Netherlands)

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

2014-01-01

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

TLD environmental monitoring at the Institute of Nuclear Engineering in Brazil

Energy Technology Data Exchange (ETDEWEB)

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

2008-09-15

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

Dosimetric evaluation of the response of the TLD-100 dosemeters in the IMRT technique by 'Step and Shoot'; Evaluacion dosimetrica de la respuesta de los dosimetros TLD-100 en la tecnica de IMRT por 'Step and Shoot'

Energy Technology Data Exchange (ETDEWEB)

Vasquez, J. [Fundacion Clinica Valle del Lili, A.A. 020338, Cali (Colombia); Benavides, S.O. [Depto. de Fisica, Universidad del Valle, A.A. 25360, Cali (Colombia)

2005-07-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-06-15

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

Individual dosimetry in planned, existing and accidental exposure situations

International Nuclear Information System (INIS)

Gomaa, M.A.M; El Deen, T.S.; Morsy, T.; Shabon, M.H.

2010-01-01

There are three types of radiation exposure which include Planned exposure situations, Existing exposure situations and Emergency exposure situations which are defined as Situations that may occur during the operation of a planned situation, or from a malicious act, or from any other unexpected situation, and require urgent action in order to avoid or reduce undesirable consequences. A given individual may be exposed as a worker, and/or as a member of the public, and/or as a patient. Workers in medical professions involving radiation are occupationally exposed. For individual monitoring of exposed workers, Film badges or thermo luminescence dosimeters are in use. In cases where individual may be suspected to be contaminated internally, contamination monitors are used to monitor the site and whole body counters to monitor individuals. Members of the public are exposure to cosmic rays during air flights. Film badges were used to exposure of workers to NORM during maintenance work in old oil field. TLD is used for exposure workers in nuclear medicine department. Any radiation accident will add knowledge and experience. Accidents from lost, stolen or neglected sources are particularly special because the radiation exposure patterns of the individuals involved and the scenario of the accident are always different

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

International Nuclear Information System (INIS)

Vasquez, J.; Benavides, S.O.

2005-01-01

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

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

International Nuclear Information System (INIS)

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

2014-08-01

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

Comparative study of main dosimetric characteristics between the GR-200A and MCP-N LiF (Mg, Cu, P) TLD chips

International Nuclear Information System (INIS)

Shen Wenxiu; Tang Kaiyong; Wang Shoushan; Cai Gangang; Zhu Hongying; Lu Min

1999-01-01

GR-200A and MCP-N are the same kind of LiF(Mg, Cu, P) chip detectors. The main dosimetric characteristics of two LiF (Mg, Cu, P) chip TLDs (GR-200A made in Solid Dosimetric Detector and Method Laboratory, Beijing, and MCP-N made in Poland) are compared, including glow curve structure, TL sensitivity, anti-moisture, reproducibility, background, detection threshold and photosensitivity. Sensitivity of GR-200a is 1.6 times as much as that of MCP-N. The sensitivity of GR-200A is stable after being used for six times, but the sensitivity of MCP-N dropped 2.8%, and its colour turned from white into light brown. The sensitivity and colour of GR-200A did not vary after being stored for 25 days at 98% RH, by comparison the sensitivity of MCP-N dropped 14%, and its colour turned into light brown. It was found that the GR-200A TLD is superior to the MCP-N TLD in above-mentioned characteristics

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

International Nuclear Information System (INIS)

Sagastibelza Chivite, F.

1980-01-01

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

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

International Nuclear Information System (INIS)

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

1977-01-01

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

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

International Nuclear Information System (INIS)

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

2008-01-01

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

Evaluation of the uncertainties in the TLD radiosurgery postal dose system

Science.gov (United States)

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

2018-03-01

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

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

International Nuclear Information System (INIS)

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

1999-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-06-01

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

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

International Nuclear Information System (INIS)

Sina, S; Sadeghi, M; Faghihi, R

2014-01-01

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

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

Science.gov (United States)

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

2016-09-01

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

Performance test of a portable TLD system for accidental doses

International Nuclear Information System (INIS)

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

2005-01-01

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

Application of environmental Cs-137 techniques to problems of sediment redistribution Sungai Lui Representative Basin, Selangor, Malaysia

International Nuclear Information System (INIS)

Daud bin Mohamad; Moo Siew Pheng.

1980-10-01

Secondary standard dosimetry laboratory (UPDK), Nuclear Energy Unit, is well equipped with all necessary irradiation facilities and radiation measuring devices. The establishment of the Laboratory is partly aimed at giving calibration services for all kinds of dosemeters, personnel radiation monitoring by using film badges and TLD etc. In running the above services, safe and correct handling procedures of the mentioned facilities and devices are necessary. Furthermore, the accuracy of measurements is of great importance. This report outlined the procedures of handling the equipment, of performing experimental works as well as of getting the mentioned services from UPDK. This report is referred as a guide containing all the standard procedures aiming at a safety operation of radiation and electrical devices and finally to achieve a high degree of dosimetric accuracies. (author)

Skin dose assessment in routine personnel beta/gamma dosimetry

International Nuclear Information System (INIS)

Christensen, P.

1980-01-01

Three alternative methods are outlined by which substantial improvements of the capabilities of existing routine monitoring systems for skin dose assessment can be obtained. The introduction of a supplementary skin dosemeter may be an attractive method for systems with badges that have a capability for an additional dosemeter already built-in. The two-side reading method has limited possibilities because of reduced accuracy for mixed radiation and technical difficulties in using it for TLD systems with planchet heating. The use of a boron diffused LiF layer for skin dose assessment seems to be most attractive method since the only modification needed here is replacement of a dosemeter. However the study of this method is so far only in a preliminary stage and further investigations are needed. (U.K.)

The effect of sample/planchet geometry and temperature resolution on the reproducibility of glow curve shapes and precision of dose measurement in LiF-TLD-100 thermoluminescent dosimetry

International Nuclear Information System (INIS)

Sibony, D.; Horowitz, Y.; Oster, L.

2014-01-01

The effect of accurate positioning of TLD-100 samples in the center of the reader planchet on precision and kinetic parameters was investigated. Significant improvement in precision is obtained by careful positioning of the sample in the center of the planchet, by as much as 40%, 20% and 30% using different methods of glow curve analysis to estimate the intensity of the TL signal. - Highlights: • The effect of accurate positioning of TLD-100 samples on precision and kinetic parameters was investigated. • Significant improvement in precision was obtained. • Significant improvement in the calculation of the kinetic parameters of individual peaks was achieved. • The optimum protocol involves a depression matched to the size of the sample was developed

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

International Nuclear Information System (INIS)

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

1994-01-01

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

Review and analysis of the over exposure cases in the non-DAE institutions in India during 2004-2007

International Nuclear Information System (INIS)

Varadharajan, Geetha; Srivastava, Kshama; Kolambe, D.H.; Punekar, M.P.; Kher, R.K.

2008-01-01

The radiation protection programme aims at providing adequate protection from undue radiation exposure to the personnel directly or indirectly involved with radiation, without limiting the benefits of radiation. Personnel Monitoring of the radiation workers is an integral part of effective radiation protection programme and is mandatory as per the Radiation Protection Rule-71 (RPR-71) and its revised version in 2004 (RPR -2004). In India, countrywide personnel monitoring of 65,000 radiation workers is carried out by 14 TLD units spread all over the country using CaSO 4 :Dy based TLD Badge system developed by Bhabha Atomic Research Centre. Prior to the accreditation of the first private laboratory in 1999, the personnel monitoring service was provided by Bhabha Atomic Research Centre. At present the total workload of about 35000 workers in the non-DAE sector has been transferred to the three private accredited laboratories catering the service in different zones of the country. The effective radiation control and safe work practices can be ensured by proper reporting of doses and investigation and follow up of overexposure cases. Any exposure exceeding 10 mSv in a singe monitoring period is treated as a case of over exposure and such cases are discussed by an AERB appointed investigation committee. The committee decides the genuineness of the exposure after looking into the various aspects relevant to these cases. This paper presents the analysis of over exposure cases reported for non-DAE institutions in the field of medicine, industry and research in India during 2004-2007. (author)

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

Energy Technology Data Exchange (ETDEWEB)

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

2011-10-15

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

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

International Nuclear Information System (INIS)

Mora, Patricia; Porras Chaverria, Mariela

2008-01-01

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

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

International Nuclear Information System (INIS)

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

2001-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2011-10-15

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-11-07

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

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

International Nuclear Information System (INIS)

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

1983-01-01

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

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

International Nuclear Information System (INIS)

Morales C, M.

2000-09-01

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

Pre-school reading badge called "Iridescent Little Fish" and its impact on reading habits later in life

Directory of Open Access Journals (Sweden)

Slavka Kristan

1997-01-01

Full Text Available The project called Footsteps to the Book is being carried out at the youth department of the Library Miran Jarc in Novo mesto; in it, preschool children from the municipalities Novo mesto, Šentjernej and Škocjan participate. The child wins the reading badge - Iridescent Little Fish with a pin - by telling four stories (or poemsin the library that havebeen told or read to him by his parents. Family appreciation can be won by both parents and children. The project has been started with the intention of lessening the impact of media upon children, and of strengthening the spiritual bondage among parents and children through reading. The purpose of the above mentioned activity is to develop and enrich child's language and thinking and help h im form positive self esteem. Through family reading, we tried to attract to the library not only small children but also their parents and to get them accustomed to the regular use of library materials. The opinions of parents,librarians, teachers and educators are very encouraging and the cooperation of children is better each year.

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

International Nuclear Information System (INIS)

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

1978-01-01

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

Pulse monitor for upper extremities dosimetry in nuclear medicine

International Nuclear Information System (INIS)

Cledison de Jesus, Cunha; Divanizia do Nascimento, Souza

2006-01-01

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

Design and implementation of a ''cheese'' phantom-based Tomotherapy TLD dose intercomparison

Energy Technology Data Exchange (ETDEWEB)

Schiefer, Hans; Buchauer, Konrad; Heinze, Simon [Medical Physics Group, Department of Radiation Oncology, St. Gallen (Switzerland); Henke, Guido; Plasswilm, Ludwig [Department of Radiation Oncology, St. Gallen (Switzerland)

2015-11-15

The unique beam-delivery technique of Tomotherapy machines (Accuray Inc., Sunnyvale, Calif.) necessitates tailored quality assurance. This requirement also applies to external dose intercomparisons. Therefore, the aim of the 2014 SSRMP (Swiss Society of Radiobiology and Medical Physics) dosimetry intercomparison was to compare two set-ups with different phantoms. A small cylindrical Perspex phantom, which is similar to the IROC phantom (Imaging and Radiation Oncology Core, Houston, Tex.), and the ''cheese'' phantom, which is provided by the Tomotherapy manufacturer to all institutions, were used. The standard calibration plans for the TomoHelical and TomoDirect irradiation techniques were applied. These plans are routinely used for dose output calibration in Tomotherapy institutions. We tested 20 Tomotherapy machines in Germany and Switzerland. The ratio of the measured (D{sub m}) to the calculated (D{sub c}) dose was assessed for both phantoms and irradiation techniques. The D{sub m}/D{sub c} distributions were determined to compare the suitability of the measurement set-ups investigated. The standard deviations of the TLD-measured (thermoluminescent dosimetry) D{sub m}/D{sub c} ratios for the ''cheese'' phantom were 1.9 % for the TomoHelical (19 measurements) and 1.2 % (11 measurements) for the TomoDirect irradiation techniques. The corresponding ratios for the Perspex phantom were 2.8 % (18 measurements) and 1.8 % (11 measurements). Compared with the Perspex phantom-based set-up, the ''cheese'' phantom-based set-up without individual planning was demonstrated to be more suitable for Tomotherapy dose checks. Future SSRMP dosimetry intercomparisons for Tomotherapy machines will therefore be based on the ''cheese'' phantom set-up. (orig.) [German] Die einzigartige Bestrahlungstechnik mit Tomotherapie-Bestrahlungsgeraeten (Accuray Inc., Sunnyvale, CA, USA) erfordert spezifische

Haste makes waste: accelerated molt adversely affects the expression of melanin-based and depigmented plumage ornaments in house sparrows.

Directory of Open Access Journals (Sweden)

Csongor I Vágási

2010-12-01

Full Text Available Many animals display colorful signals in their integument which convey information about the quality of their bearer. Theoretically, these ornaments incur differential production and/or maintenance costs that enforce their honesty. However, the proximate mechanisms of production costs are poorly understood and contentious in cases of non-carotenoid-based plumage ornaments like the melanin-based badge and depigmented white wing-bar in house sparrows Passer domesticus. Costly life-history events are adaptively separated in time, thus, when reproduction is extended, the time available for molt is curtailed and, in turn, molt rate is accelerated.We experimentally accelerated the molt rate by shortening the photoperiod in order to test whether this environmental constraint is mirrored in the expression of plumage ornaments. Sparrows which had undergone an accelerated molt developed smaller badges and less bright wing-bars compared to conspecifics that molted at a natural rate being held at natural-like photoperiod. There was no difference in the brightness of the badge or the size of the wing-bar.These results indicate that the time available for molt and thus the rate at which molt occurs may constrain the expression of melanin-based and depigmented plumage advertisements. This mechanism may lead to the evolution of honest signaling if the onset of molt is condition-dependent through the timing of and/or trade-off between breeding and molt.

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

Energy Technology Data Exchange (ETDEWEB)

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

2007-07-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1984-01-01

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

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

International Nuclear Information System (INIS)

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

2002-01-01

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

Radiation exposure of non-monitored hospital personnel

International Nuclear Information System (INIS)

Renaud, L.; Blanchette, J.; Galand, C.

1993-02-01

This project investigated the radiological impact of nuclear medicine patients on non-monitored personnel in hospital environments. More than 800 workers and 135 specific areas in three Quebec hospitals were surveyed daily during a six-month period with Geiger counters, TLD badges, and TLD chips. Average dose rates of up to 2.2 μSv/h were measured in some waiting areas. The radiation level of a nursing unit is a direct function of the ambulatory radioactivity carried by nuclear medicine patients. Three percent of the workers surveyed had a work-related dose in excess of 0.3 mSv/6 months (maximum 1.4 mSv/6 months). Over 88 percent were in the range between local background and 0.3 mSv/6 months. Less than 4 percent belong to groups of workers who were exposed to a level indistinguishable from background. Thus many workers surveyed in this study receive a work-related dose similar to those of medical workers monitored by Health and Welfare Canada. The average annual dose for these workers was 104 person-millisieverts. The authors recommend: better management of radioactive patients; the provision of information and education for all hospital workers having regular contact with radioactive patients; and the facilitation of the identification of nuclear medicine patients within the hospital environment. (28 tabs., 23 figs.)

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

International Nuclear Information System (INIS)

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

2011-10-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-11-01

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

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)

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

International Nuclear Information System (INIS)

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

2011-10-01

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

Environmental gamma radiation monitoring at Visakhapatnam using thermoluminescence dosimeters

International Nuclear Information System (INIS)

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

2012-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Estrada E, D

2002-07-01

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

Photon and neutron doses of the personnel using moisture and density measurement devices

Energy Technology Data Exchange (ETDEWEB)

Carinou, E.; Papadomarkaki, E.; Tritakis, P.; Hourdakis, C.I.; Kamenopoulou, V. [Greek Atomic Energy Commission, Agia Paraskevi, Attiki, 60092 (Greece)

2006-07-01

The objective of this study is to present the evolution of the photon doses received by the workers who use mobile devices for measuring the moisture and the density in various materials and to estimate the neutron doses. The workers employed in more than 30 construction companies in Greece were 76 in 2004. The devices used for that purpose incorporate a {sup 137}Cs source for density measurements and an {sup 241}Am-Be source for moisture measurements of soil, asphalt or concrete. Photon and neutron measurements were performed occasionally during the on site inspections. The results of the measurements showed that the photon and neutron dose rates were not negligible. The workers were monitored for photon radiation using film badges (Kodak Type 2, Holder NRPB type) till the year 2000 and then TLD badges issued by the Greek Atomic Energy Commission (GAEC), on a monthly basis. Since the neutron dose rates measured by a rem-meter were not so high, no neutron dosemeters were issued for them. Their personal dose equivalent data for photons are kept in the National Dose Registry Information System (N.D.R.I.S.) in G.A.E.C. and were used for statistical analysis for the period from 1997 till 2004. As far as the neutrons are concerned, a Monte Carlo code was used to simulate the measuring devices and the working positions in order to calculate the neutron individual doses. (authors)

Photon and neutron doses of the personnel using moisture and density measurement devices

International Nuclear Information System (INIS)

Carinou, E.; Papadomarkaki, E.; Tritakis, P.; Hourdakis, C.I.; Kamenopoulou, V.

2006-01-01

The objective of this study is to present the evolution of the photon doses received by the workers who use mobile devices for measuring the moisture and the density in various materials and to estimate the neutron doses. The workers employed in more than 30 construction companies in Greece were 76 in 2004. The devices used for that purpose incorporate a 137 Cs source for density measurements and an 241 Am-Be source for moisture measurements of soil, asphalt or concrete. Photon and neutron measurements were performed occasionally during the on site inspections. The results of the measurements showed that the photon and neutron dose rates were not negligible. The workers were monitored for photon radiation using film badges (Kodak Type 2, Holder NRPB type) till the year 2000 and then TLD badges issued by the Greek Atomic Energy Commission (GAEC), on a monthly basis. Since the neutron dose rates measured by a rem-meter were not so high, no neutron dosemeters were issued for them. Their personal dose equivalent data for photons are kept in the National Dose Registry Information System (N.D.R.I.S.) in G.A.E.C. and were used for statistical analysis for the period from 1997 till 2004. As far as the neutrons are concerned, a Monte Carlo code was used to simulate the measuring devices and the working positions in order to calculate the neutron individual doses. (authors)

Application of conventional chromosomal aberration and fluorescence in-situ hybridisation translocation in the assessment of occupationally derived irradiation

International Nuclear Information System (INIS)

Samavat, H.; Seaward, M. R. D.; Gonzales, D. H.; Azizian, Gh.

2004-01-01

Background: Most of our current understanding of the biological effects of exposure to ionising radiation is based on conventional cytogenetic techniques, which enable our to determine the relationship between chromosomal aberration and dose received by radiation workers. However, conventional techniques have numerous limitations and chromosomal aberrations can be easily missed. Since fluorescence in situ hybridisation plays an important role in detecting chromosomal changes, this method was used to reassess data derived from previous studies employing conventional techniques. Materials and Methods: Two groups of radiographers were the subject of a study on conventional chromosomal aberration and fluorescence in situ hybridisation for translocation. The first group was chosen following an accidental contamination incident in a nuclear medicine department. The second group was composed of six radiographers working in an x-ray department with a previous record of overdose as recorded by film-badges; these workers had been the subjects of a previous chromosomal study. Coded blood samples from 11 radiographers and 11 controls were analysed for chromosomal aberration and by fluorescence in-situ hybridisation for translocation. 200 metaphases from the peripheral blood lymphocytes per subject were analysed to investigate possible frequencies of chromosome and chromatid type aberration and 2000 metaphases per subject were scored in fluorescence in-situ hybridisation method. Results: There was no significant difference between the radiographers and the control groups in conventional analysis; also there was no significant difference at the 95 % level of confidence in fluorescence in-situ hybridisation analysis. There was no correlation between levels of translocation and total lifetime doses from occupational ( according film-badge and TLD) and/or background irradiation. Conclusion: The overall conclusion is that the frequency of chromosomal damage in both groups of

Radiological surveillance employed at industrial application in a nuclear research centre

International Nuclear Information System (INIS)

Sanches, M.P.; Sordi, G.M.; Sahyun, A.; Rodrigues, D.L.

1996-01-01

The monitoring and dosimetry systems used at Industrial Application and Engineering Service Department of the Instituto de Pesquisas Energeticas e Nucleares of the Brazilian Nuclear Energy Commission (GE-IPEN-CNEN/SP) are analyzed,in order to verify the compliance with the condition established by the dose system limitation and the basic radiation protection standards. The criteria about the use of individual dosimetry for persons that work in these facilities are established. In case of an external radiation dosimetry, by using film badge method, a level of 200μGy has been assigned, considering the detection significant threshold. For dose in air due to electromagnetic radiation, using TLD dosimetry of CaSO 4 :Dy a quarter year significant threshold is 101μGy. A symbiosis between the workplace monitoring and the individual monitoring became necessary for optimization purpose. (authors). 5 refs., 2 tabs., 1 fig

Radiation exposure of nurses in a coronary care unit

International Nuclear Information System (INIS)

Jankowski, C.B.

1984-01-01

In response to increasing awareness of radiation as a possible occupational hazard, nursing personnel staffing a hospital CCU were monitored over a 3-year period to determine occupational exposure. Portable x-ray machines, fluoroscopic units, and patients injected with radiopharmaceuticals were all potential radiation sources on such a unit. Whole-body TLD badges, exchanged monthly, indicated no cumulative exposures over 80 mR during the entire study period. The minimal exposures reported do not justify regular use of dosimeters. Adherence to standard protective measures precludes most exposure to machine-produced radiation. Close, prolonged contact with a patient after an RVG study that utilizes /sup 99m/Tc may account for some exposure. The data indicate that radiation is not a significant occupational hazard for CCU nurses at this hospital; similar minimal exposures would be expected of other nonoccupationally exposed nursing personnel in like environments

Calibration of instrument and personnel monitoring in radiological protection

International Nuclear Information System (INIS)

Abdul Aziz Mohamad Ramli; Wan Saffiey Wan Abdullah

1987-01-01

It is difficult to choose radioprotection equipments that are not too expensive and suit the purpose. Some of the dosimetric characteristics of good dosemeters outlined by ISO 4071-1978 (E) namely scale linearity, energy dependence, radiation quality dependence and angular dependence for some of the commercially available dosemeters are discussed. The calibration procedures practised at the National Secondary Standard Dosimetry Laboratory (SSDL), of the Nuclear Energy Unit (NEU) is also explained. The radiological equipments for personnel monitoring such as film badge and TLD are widely used to estimate the radiation dose delivered to the whole or partial body of a personnel. Both of the personnel monitoring procedures have been established at the NEU. The objective, use and maintenance of the devices are also discussed in detail. The evaluation of the monthly dose received by a personnel from various establishments in the country are also presented. (author). 17 figs

Real time gamma monitoring for employees working in an operational underground copper / uranium mine

International Nuclear Information System (INIS)

Lawrence, Cameron E.

2010-01-01

For many years electronic devices have been available that are compact enough to utilise for personal gamma radiation monitoring. At BHP Billiton's Olympic Dam underground copper / uranium mine two different types of electronic gamma dosimeters are being used to assess and control exposure to gamma rays present in the underground operations. Canberra Dosicards are being used as part of a program that replaced the use of monthly issued Thermoluminescent Dosimeter (TLD) badges with quarterly issue for some work groups. Two types of Polimaster gamma watches have also been introduced to specific work groups to assist with the determination of sites that may require remedial controls for their level of gamma radiation. To date, both programs have been successfully implemented into the radiation monitoring program for the underground operation and have provided dramatic improvements for the control and determination of sources of gamma radiation in the underground environment.

IAEA/ WHO TLD postal dose intercomparison results in Bangladesh

International Nuclear Information System (INIS)

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

2001-01-01

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

Quality control in medical radiology using T.L.D

International Nuclear Information System (INIS)

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

2006-01-01

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

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

International Nuclear Information System (INIS)

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

2000-01-01

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

Dose measurements in space by the Hungarian Pille TLD system

International Nuclear Information System (INIS)

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

2002-01-01

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

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

International Nuclear Information System (INIS)

Flores M, E.

2007-01-01

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

Concentrations of bisphenol a, bisphenol a diglycidyl ether, and their derivatives in canned foods in Japanese markets.

Science.gov (United States)

Yonekubo, Jun; Hayakawa, Kazuichi; Sajiki, Junko

2008-03-26

Bisphenol A (BPA), bisphenol A diglycidyl ether (BADGE), and their derivatives in 38 canned foods sold in Japan were measured using high-performance liquid chromatography-mass spectrometry (LC-MS) and LC-tandem mass spectrometry (LC-MS/MS). BPA, BADGE, BADGE.2H 2O, BADGE.HCl.H2O, BADGE.HCl, and BADGE.2HCl were 0-235.4, 0-3.4, 0-247.2, 0.2-196.4, 0-3.0, and 0-25.7 ng/g, respectively, which did not exceed acceptable daily intake for BPA and specific migration limit for BADGEs. BADGE was degraded by 58, 100, 46, and 58% in water (pH 7), 0.01 N HCl (pH 2), 0.01 N NaCl (pH 6.8), and 0.01 N NaCl with acetic acid (pH 2.5), respectively, when it was allowed to stand at 120 degrees C for 30 min. The prominent derivatives formed were BADGE.2H 2O and BADGE.HCl.H2O, which was formed not only in BADGE with added HCl but also in that with NaCl. Acetic acid accelerated the formation of both BADGE.2H2O and BADGE.HCl.H2O in NaCl. No BPA was detected in any simulation samples started from BADGE. The results suggest that BPA and BADGE are independently leached into canned foods and that BADGE is easily changed to more stable compounds such as BADGE.2H2O and BADGE.HCl.H2O by sterilization.

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

Science.gov (United States)

Eakins, Jonathan

2009-02-01

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

Development of neutron induced prompt γ-ray spectroscopy system using 252Cf

International Nuclear Information System (INIS)

Park, Yong-Joon; Song, Byung-Chul; Jee, Kwang-Yong

2003-01-01

For the design and set-up of neutron induced prompt γ-ray spectroscopy system using 252 Cf neutron source, the effects of shielding and moderator materials have been examined. The 252 Cf source being used for TLD badge calibration in Korea Atomic Energy Research Institute was utilized for this preliminary experiment. The γ-ray background and prompt γ-ray spectrum of the sample containing Cl were measured using HPGe (GMX 69% relative efficiency) located at the inside of the system connected to notebook PC at the outside of the system (about 20 meter distance). The background activities of neutron and γ-rays were measured with neutron survey meter as well as γ-ray survey meters, respectively and the system was designed to minimize the activities. Prompt γ-ray spectrum was measured using γ-γ coincident system for reduce the background and the continuum spectrum. The optimum system was designed and set up using the experimental data obtained

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

International Nuclear Information System (INIS)

Burgkhardt, B.; Piesch, E.

1981-01-01

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

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

International Nuclear Information System (INIS)

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

1996-01-01

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

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

International Nuclear Information System (INIS)

Estrada E, D.

2002-01-01

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

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

Science.gov (United States)

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

2002-01-01

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

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

International Nuclear Information System (INIS)

Marino, Emiliano A.

2013-01-01

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

Clinical evaluation of a dose monitoring software tool based on Monte Carlo Simulation in assessment of eye lens doses for cranial CT scans

Energy Technology Data Exchange (ETDEWEB)

Guberina, Nika; Suntharalingam, Saravanabavaan; Nassenstein, Kai; Forsting, Michael; Theysohn, Jens; Wetter, Axel; Ringelstein, Adrian [University Hospital Essen, Institute of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany)

2016-10-15

The aim of this study was to verify the results of a dose monitoring software tool based on Monte Carlo Simulation (MCS) in assessment of eye lens doses for cranial CT scans. In cooperation with the Federal Office for Radiation Protection (Neuherberg, Germany), phantom measurements were performed with thermoluminescence dosimeters (TLD LiF:Mg,Ti) using cranial CT protocols: (I) CT angiography; (II) unenhanced, cranial CT scans with gantry angulation at a single and (III) without gantry angulation at a dual source CT scanner. Eye lens doses calculated by the dose monitoring tool based on MCS and assessed with TLDs were compared. Eye lens doses are summarized as follows: (I) CT angiography (a) MCS 7 mSv, (b) TLD 5 mSv; (II) unenhanced, cranial CT scan with gantry angulation, (c) MCS 45 mSv, (d) TLD 5 mSv; (III) unenhanced, cranial CT scan without gantry angulation (e) MCS 38 mSv, (f) TLD 35 mSv. Intermodality comparison shows an inaccurate calculation of eye lens doses in unenhanced cranial CT protocols at the single source CT scanner due to the disregard of gantry angulation. On the contrary, the dose monitoring tool showed an accurate calculation of eye lens doses at the dual source CT scanner without gantry angulation and for CT angiography examinations. The dose monitoring software tool based on MCS gave accurate estimates of eye lens doses in cranial CT protocols. However, knowledge of protocol and software specific influences is crucial for correct assessment of eye lens doses in routine clinical use. (orig.)

Clinical evaluation of a dose monitoring software tool based on Monte Carlo Simulation in assessment of eye lens doses for cranial CT scans

International Nuclear Information System (INIS)

Guberina, Nika; Suntharalingam, Saravanabavaan; Nassenstein, Kai; Forsting, Michael; Theysohn, Jens; Wetter, Axel; Ringelstein, Adrian

2016-01-01

The aim of this study was to verify the results of a dose monitoring software tool based on Monte Carlo Simulation (MCS) in assessment of eye lens doses for cranial CT scans. In cooperation with the Federal Office for Radiation Protection (Neuherberg, Germany), phantom measurements were performed with thermoluminescence dosimeters (TLD LiF:Mg,Ti) using cranial CT protocols: (I) CT angiography; (II) unenhanced, cranial CT scans with gantry angulation at a single and (III) without gantry angulation at a dual source CT scanner. Eye lens doses calculated by the dose monitoring tool based on MCS and assessed with TLDs were compared. Eye lens doses are summarized as follows: (I) CT angiography (a) MCS 7 mSv, (b) TLD 5 mSv; (II) unenhanced, cranial CT scan with gantry angulation, (c) MCS 45 mSv, (d) TLD 5 mSv; (III) unenhanced, cranial CT scan without gantry angulation (e) MCS 38 mSv, (f) TLD 35 mSv. Intermodality comparison shows an inaccurate calculation of eye lens doses in unenhanced cranial CT protocols at the single source CT scanner due to the disregard of gantry angulation. On the contrary, the dose monitoring tool showed an accurate calculation of eye lens doses at the dual source CT scanner without gantry angulation and for CT angiography examinations. The dose monitoring software tool based on MCS gave accurate estimates of eye lens doses in cranial CT protocols. However, knowledge of protocol and software specific influences is crucial for correct assessment of eye lens doses in routine clinical use. (orig.)

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

Energy Technology Data Exchange (ETDEWEB)

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

1998-12-31

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

Poster - 24: Characterization of the energy dependence of high-sensitivity MCP-N TLD and Al2O3:C OSLD in-vivo dosimetry systems for 40–100 kVp energies

Energy Technology Data Exchange (ETDEWEB)

Poirier, Yannick; Kuznetsova, Svetlana; Barajas, Eduardo Villarreal [Tom Baker Cancer Centre, Calgary AB, University of Calgary, Calgary AB, Tom Baker Cancer Center/University of Calgary, Calgary AB (Canada)

2016-08-15

Purpose: To characterize the energy dependence of high-sensitivity MCP-N TLD and Al{sub 2}O{sub 3}:C OSLD dosimetry systems at low (40–100 kVp) energies for in-vivo dosimetry. Methods: We assessed the variation of response with energy of two detectors in the 40–100 kVp energy range: high-sensitivity MCP-N TLDs (LiF:Mg,Cu,P) and OSLDs (Al{sub 2}O{sub 3}:C). The detectors were irradiated with an XRad 320ix biological irradiator under reference conditions. The delivered dose was 10 cGy for 7 beam qualities ranging from 40–100 kVp, 1.7–4.0 mm Al, and effective energies 26.9–37.9 keV. Both sets of detectors were also irradiated under reference conditions at 6 MV using a Varian Clinac 21Ex to assess the change in response from high-energy beams. Results: The MCP-N high-sensitivity TLDs were relatively insensitive to energies in the kV range, as their response varied by ±5%, i.e. well within the reproducibility limits of these detectors. However, the OSLDs exhibited a linearly-decreasing response with energy with a response 18.7% higher at 40 kVp than at 100 kVp for the same nominal dose. Compared to the 6 MV beams used in conventional radiotherapy, OSLDs responded 3.3–3.9 times higher depending on beam quality while the MCP-N TLD response was unchanged within experimental uncertainty. Conclusions: Unlike the more commonly used TLD-100, the high-sensitivity MCP-N TLDs exhibit little to no energy response. OSLDs are shown to be highly energy-dependent, both from MV to kV and within the kV range.

Characterization of TLD-100 in powders for dosimetric quality control of 192 Ir sources used in brachytherapy of high dose rate

International Nuclear Information System (INIS)

Loaiza C, S.P.

2007-01-01

The Secondary Standard Dosimetric at the National Institute of Nuclear Research (ININ) calibrated a lot of powdered TLD-100 (LiF:Mg,Ti) in terms of absorbed dose to water D w for the energy of: 60 Co, 137C s, X rays of 250 and 50 kVp. Later on, it is carried out an interpolation of the calibration for the energy of the 192 Ir. This calibration is part of a dosimetric quality control program, to solve the problems of traceability for the measurements carried out by the users of 192 Ir sources employed in the treatments of High Dose Rate Brachytherapy (HDR) at the Mexican Republic. The calibrations of the radiation beams are made with the following protocols: IAEA TRS-398 for the 60 Co for D w , using a secondary standard ionization chamber PTW N30013 calibrated in D w by the National Research Council (NRC, Canada). AAPM TG-43 for D w in terms of the strength kerma Sk, calibrating this last one quantity for the 137 Cs radioactive source, with a well chamber HDR 1000 PLUS traceable to the University of Wisconsin (US). AAPM TG-61 for X ray of 250 and 50 kVp for D w start to Ka using field standard a Farmer chamber PTW 30001 traceable to K for the Central Laboratory of Electric Industries (CLEI, France). The calibration curves (CC) they built for the response of the powder TLD: R TLD vs D w : For the energy of 60 Co, 137 Cs, X rays of 250 and 50 kVp. Fitting them with the least square method weighed by means of a polynomial of second grade that corrects the supra linearity of the response. iii. Each one of the curves was validated with a test by lack of fitting and for the Anderson Darling normality test, using the software MINITAB in both cases. iv. The sensibility factor (F s ) for each energy corresponds to the slope of the CC, v. The F s for the two 192 Ir sources used are interpolated: one for a Micro Selectron source and the other one a Vari Source source. Finally, a couple of capsules were sent to two hospitals that have the HDR Brachytherapy with sources of 192

Radiation incident in oil well logging

International Nuclear Information System (INIS)

Lozada, J.A.

1998-01-01

On June 4th 1997 equipment failure and violation of approved procedures by a crew of workers initiated a series of events that resulted in the unnecessary exposure to neutron and gamma radiation, from a 666 GBq Am 241 Be source, of forty two workers from a well logging company in Venezuela. Due to the presence of dry mud or drilling fluids inside the logging tool, the nosepiece was screwed off the rest of the source holder; this piece was mistaken for the entire source holder thus leaving the source inside the tool. The tool was labelled for maintenance and electronic laboratory personal worked near the source for seven hours before they identify its presence. As soon as the incident was detected a contingency plan was implemented and the source could be retrieved from the tool and placed in its shipping container. The TLD badges indicate doses well below the annual limit of 20 mSv, and none of the workers involved in the incident seem to show serious health consequences from it. After the incident, in order to avoid the occurrence of similar situations, a better source and tool maintenance program was implemented, all the workers were re-trained, and area monitors were installed in all operations bases. (author)

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

International Nuclear Information System (INIS)

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

2008-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-10-15

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

Annual radiation background in Isfahan city

International Nuclear Information System (INIS)

Tavakoli, Mohammad B.

2002-01-01

Measurement of environmental exposure is very important from different points of view. It is especially important for human health. It has been measured accurately in many countries. In Iran, it is also measured in some cities especially in high background areas such as Ramsar, but there is not any measurement in Isfahan. Measurement of background radiation in this study is performed using TLD method. The TLDs used are made from CaSO 4 :Dy, which is very sensitive. The locations under investigations in this research were 52 health centers distributed all around Isfahan city. Each TLD badge was put in a special plastic bag and left over the roofs of the selected health center for a month. The procedure was repeated for all 12 months of the year 1379(21 st March 2000 to 20 th March 2001). The results were used to obtain mean and SD in each month and at different places. The maximum and the minimum of obtained results for dose equivalent in different months and locations were 15.9x10 -2 and 6.5x10 -2 mSv. Obtained maximum and minimum of the means between all the locations were 10.5x10 -2 and 8.6x10 2 mSv for the whole year. Monthly mean and SD for Isfahan city for the whole year were 9.7x10 -2 and 1.5x10 -2 respectively therefore mean annual dose equivalent in Isfahan city is 1.16mSv. The results do not show any high background radiation area

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

International Nuclear Information System (INIS)

Jin Hua

1993-01-01

The paper describes the design of a new LiF TL dosimeter optimized for measuring personal dose equivalent, H p (d). The results obtained with four types of different phantoms, i.e. a PMMA slab, water slab, ICRU sphere and Alderson Rando phantom, and pertinent conversion coefficients show, that the conversion coefficients for the TE slab phantom are suitable for the calibration of TLD individual dosimeters on a PMMA slab phantom. In the energy range 17 keV to 1250 keV the energy response for H 0 (10) and H p (0.07) is within-20% to 8.4% for frontal irradiation. For angles within +- 60 degree the dosimeters indicate H p (10) within 0 to 22.5%, and H p (0.07) within-11.1% to 1.3%. respectively

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-06-01

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

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

International Nuclear Information System (INIS)

Kodeli, I.; Tanner, R.

2005-01-01

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

Characterization of TLD-100 in powders for dosimetric quality control of {sup 192} Ir sources used in brachytherapy of high dose rate; Caracterizacion de TLD-100 en polvo para control de calidad dosimetrico de fuentes de Ir{sup 192} usadas en braquiterapia de alta tasa de dosis

Energy Technology Data Exchange (ETDEWEB)

Loaiza C, S.P

2007-07-01

The Secondary Standard Dosimetric at the National Institute of Nuclear Research (ININ) calibrated a lot of powdered TLD-100 (LiF:Mg,Ti) in terms of absorbed dose to water D{sub w} for the energy of: {sup 60}Co, {sup 137C}s, X rays of 250 and 50 kVp. Later on, it is carried out an interpolation of the calibration for the energy of the {sup 192}Ir. This calibration is part of a dosimetric quality control program, to solve the problems of traceability for the measurements carried out by the users of {sup 192}Ir sources employed in the treatments of High Dose Rate Brachytherapy (HDR) at the Mexican Republic. The calibrations of the radiation beams are made with the following protocols: IAEA TRS-398 for the {sup 60}Co for D{sub w}, using a secondary standard ionization chamber PTW N30013 calibrated in D{sub w} by the National Research Council (NRC, Canada). AAPM TG-43 for D{sub w} in terms of the strength kerma Sk, calibrating this last one quantity for the {sup 137}Cs radioactive source, with a well chamber HDR 1000 PLUS traceable to the University of Wisconsin (US). AAPM TG-61 for X ray of 250 and 50 kVp for D{sub w} start to Ka using field standard a Farmer chamber PTW 30001 traceable to K for the Central Laboratory of Electric Industries (CLEI, France). The calibration curves (CC) they built for the response of the powder TLD: R{sub TLD} vs D{sub w}: For the energy of {sup 60}Co, {sup 137}Cs, X rays of 250 and 50 kVp. Fitting them with the least square method weighed by means of a polynomial of second grade that corrects the supra linearity of the response. iii. Each one of the curves was validated with a test by lack of fitting and for the Anderson Darling normality test, using the software MINITAB in both cases. iv. The sensibility factor (F{sub s}) for each energy corresponds to the slope of the CC, v. The F{sub s} for the two {sup 192}Ir sources used are interpolated: one for a Micro Selectron source and the other one a Vari Source source. Finally, a couple of

Radiation dose of staff during positron emission tomography study

Energy Technology Data Exchange (ETDEWEB)

Hachiya, Takenori; Shoji, Yasuaki; Hagami, Eiichi; Aizawa, Yasuo; Onodera, Hiroshi; Kan, Mikio; Sasaki, Nobuo; Toyoshima, Eiji; Sugawara, Shigeki

1989-04-01

In this paper, the radiation dose of the PET staff including blood sampling operators (medical doctors), PET operators (radio technologists), nurses, blood analysts (medical technologists), radiochemists and cyclotron operators in the cyclotron-PET unit was evaluated. The dose was measured using the film-badges for whole body and TLD ring-badges for fingers. These data were obtained from June, 1986 to May, 1987. In the average dose per month, those with the highest dose were radiochemists. The whole body dose was 1.08 mSv (108 mrem) for /gamma/-ray, 520 /mu/Sv (52 mrem) for /beta/-ray and the dose for fingers, 7.6mSv (760 mrem). The total dose per year both for /gamma/ and /beta/-ray was 19.2 mSv (1.92 rem) for whole body and 91.2 mSv (9.12 rem) for fingers. The staff with the lowest whole body dose for /gamma/-ray per month was blood analysts whose dose was 30 /mu/Sv (3 mrem). For the staff consisting of doctors, radiotechnologists and nurses, the whole body dose per month was 70-170/mu/Sv (7-17 mrem) for /gamma/-ray, 20 /mu/Sv (2 mrem) for /beta/-ray and the dose for fingers per month was 210-540 /mu/Sv (21-54 mrem). For cyclotron operators, the dose was 90 /mu/Sv (9 mrem) for /gamma/-ray, 30 /mu/Sv (3 mrem) for /beta/-ray and the dose for fingers was 160 /mu/Sv (16 mrem). For cyclotron operators and radiochemists, the whole body dose for the neutron ray was measured by solid state nuclear track detector (SSNTD), but the dose was found to be negligible. (author).

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

International Nuclear Information System (INIS)

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

1999-01-01

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

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)

Determination of exposure rates from natural background radiation in Khartoum using LiF:Mg,Cu,P (GR-200) and CaSo4: Mn TLD chips

International Nuclear Information System (INIS)

Suliman, I.I.; Khangi, F.A.; Shaddad, I.A.; Suliman, I.A.; El Amin, O.I.

2002-01-01

The exposure rates from natural background radiation - including terrestrial gamma radiation and the ionizing component of cosmic rays - were measured for the first time in the city of khartoum using two types of TLD materials: LiF:Mg,Cu,P (GR-200) and CaSo 4 :Mn TLD chips. Measurements were performed at two sites simultaneously, one site was selected on land in the vicinity of the Sudan Atomic Energy Commission, for the purposes of the measurement of the total exposure rate outdoors, while the other site was located on a buoy anchored in the Blue Nile, and was selected to measure the exposure rate due to the ionizing component of cosmic rays. The investigations were conducted for periods of between 5 and 28 days. Calibration was performed on a selected number of dosimeters to determine the exposure rates at each site. The exposure rates from the ionizing component of cosmic rays in Khartoum were found to be respectively 33 nGy.h -1 and 30 nGy.h -1 , in the measurements performed within the scope of this work using GR-200 and CaSo 4 :Mn dosimeters, while the total values for exposure on land were found to be 45 nGy.h -1 and 42 nGy.h -1 respectively. These values compare reasonably well with other national averages reported in the UNSCEAR publication. The comparison of the results for the two dosimetric materials demonstrates both the sensitivity and suitability of GR-200 for the purposes of environmental monitoring (orig.)

Comparative study of eye dose and chest dose received during radiopharmaceutical production processes

International Nuclear Information System (INIS)

Chindarkar, A.S.; Chavan, S.V.; Sawant, D.K.; Sahoo, L.; Gopalakrishnan, R.K.; Sneha, C.; Sachdev, S.S.; Dey, A.C.

2018-01-01

Radiopharmaceutical laboratory, BRIT, Vashi produces different radiopharmaceuticals of 131 I, 153 Sm, 99 Mo/ 99m Tc and 177 Lu. Principle gamma energies of these isotopes vary from 103 to 740 KeV and their maximum beta energies vary from 384 to 1214 KeV. In the light of the revised eye lens dose limit recommended in IAEA Basic Safety Standard Interim Edition No. GSR Part 3 (IAEA-2011), the study of radiation dose for eye lens was carried out using CaSO 4 : Dy based Thermo luminescence dosimeter (TLD). This TLD was worn at center of the forehead to measure eye lens dose. This TLD dose was then compared with chest TLD dose to deduce any correlation between these TLD doses. These TLD doses were assessed on quarterly basis. Eight quarter data of these TLD doses were compared

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

Energy Technology Data Exchange (ETDEWEB)

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

1999-07-01

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

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

International Nuclear Information System (INIS)

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

1999-01-01

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

Is dosimetry still a necessity in current dental practice?

International Nuclear Information System (INIS)

Reddy, S S; Rakesh, N; Clint, Joseph Ben; Sharma, Shivani; Chauhan, Pallavi

2015-01-01

Today, dentists have a wide range of imaging modalities to choose from, the film based techniques, digital techniques, and the recent introduction of 3D volumetric or cone beam computed tomography (CBCT). The inherent design features of the new generation dental x-ray equipment has significantly improved over the years with no evidence of substandard x-ray units in operation. In dental facilities radiological workload is comparatively low, newer radiation equipments and accessories follow safety guidelines and employ better radiation protection measures for the patient and the operator. Dentists’ knowledge and expertise in radiation protection measures is good, enabling them to carry out riskfree radiation procedures in their practice. Therefore, the present study is aimed at assessing the need for dosimeters in current dental scenario.‘Is there currently a significant risk from dental radiography to merit the use of personal dosimetery in dental practice.’Dental health professionals (Oral radiologists) and radiographic assistants of fourteen dental colleges in Karnataka state participated in this questionnaire study. The questionnaire consisted of the following questions—the make, type, year of manufacture of radiographic machines used in their setup, number of radiographs made per day in the institution, type of receptors used, number of personnel at risk for radiation exposure, radiation protection measures used, regular monitoring by personal dosimeters, equivalent dosage readings for the past 12 months and whether the reading of thermoluminescent dosimeters (TLD) for any personnel had exceeded the recommended exposure value in the last 3 years.Dosimetry records of the radiology staff in the last three years shows doses no more than 1.50 mSv per year. The various institutions’ dose (person mSv) was in the range of 3.70 mSv–3.90 mSv.Personal monitoring for Dentists can be omitted in the dental colleges since the estimated dose of oral radiologists

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

International Nuclear Information System (INIS)

Mora, P.

1998-01-01

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

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

Staff eye doses in a large medical centre in Saudi Arabia: are they meeting the new ICRP recommendations?

International Nuclear Information System (INIS)

Al-Haj, Abdalla N.; Al-Gain, Ibrahim; Lobriguito, Aida M.

2015-01-01

A 5-y retrospective analysis of the cardiology staff eye doses was performed on 34 staff from different categories (cardiologists, nurses and technologists) at King Faisal Specialist Hospital and Research Centre (KFSHRC) in Riyadh, Saudi Arabia. KFSHRC is a tertiary medical centre with 800-bed capacity having more than 5000 cardiac catheterisation procedures performed annually. The aim of the study is to derive staff doses to the lens of the eyes using the personal dose equivalent Hp(0.07) values from the annual TLD dose report for the years 2008-2012 and determine the category of staff with high estimated eye doses. The study also aims to investigate the causes for high doses and recommend dose-reduction techniques. The dose to the lens of the eye was estimated by using the ratio Hp(0.07) slab /H lens of 1.1 where Hp(0.07) values are the reported doses read from TLD badge worn at the collar level. The average annual eye dose of each category for the 5-y monitoring period was determined. Cardiologists tend to receive higher doses than the nurses by a factor of 2-4 and can exceed 5 mSv y -1 . No correlation exists between the eye doses of nurses and the cardiologists. There is a need to use a conversion coefficient in terms of eye lens dose per dose-area product for faster estimation of eye lens doses. However, there is a limitation on the use of the conversion coefficient because it will depend on the clinical procedure and the X-ray tube angulation. Further investigation on this limitation is needed. (authors)

Efficacy of a radiation absorbing shield in reducing dose to the interventionalist during peripheral endovascular procedures: a single centre pilot study.

Science.gov (United States)

Power, S; Mirza, M; Thakorlal, A; Ganai, B; Gavagan, L D; Given, M F; Lee, M J

2015-06-01

This prospective pilot study was undertaken to evaluate the feasibility and effectiveness of using a radiation absorbing shield to reduce operator dose from scatter during lower limb endovascular procedures. A commercially available bismuth shield system (RADPAD) was used. Sixty consecutive patients undergoing lower limb angioplasty were included. Thirty procedures were performed without the RADPAD (control group) and thirty with the RADPAD (study group). Two separate methods were used to measure dose to a single operator. Thermoluminescent dosimeter (TLD) badges were used to measure hand, eye, and unshielded body dose. A direct dosimeter with digital readout was also used to measure eye and unshielded body dose. To allow for variation between control and study groups, dose per unit time was calculated. TLD results demonstrated a significant reduction in median body dose per unit time for the study group compared with controls (p = 0.001), corresponding to a mean dose reduction rate of 65 %. Median eye and hand dose per unit time were also reduced in the study group compared with control group, however, this was not statistically significant (p = 0.081 for eye, p = 0.628 for hand). Direct dosimeter readings also showed statistically significant reduction in median unshielded body dose rate for the study group compared with controls (p = 0.037). Eye dose rate was reduced for the study group but this was not statistically significant (p = 0.142). Initial results are encouraging. Use of the shield resulted in a statistically significant reduction in unshielded dose to the operator's body. Measured dose to the eye and hand of operator were also reduced but did not reach statistical significance in this pilot study.

Development and characterization of two-component albedo based neutron individual monitoring system using thermoluminescent detectors

International Nuclear Information System (INIS)

Martins, Marcelo Marques

2008-01-01

A TLD-albedo based two-component neutron individual monitoring system was developed and characterized in this work. The monitor consists of a black plastic holder, an incident neutron boron loaded shield, a moderator polyethylene body (to increase its response), two pairs of TLD-600 and TLD-700 (one pair to each component) and an adjustable belt. This monitoring system was calibrated in thermal neutron fields and in 70 keV, 144 keV, 565 keV, 1.2 MeV and 5 MeV monoenergetic neutron fields. In addition, it was calibrated in 252C f(D 2 O), 252 Cf, 241 Am-B, 241 Am-Be and 238 Pu-Be source fields. For the latter, the lower detection levels are, respectively, 0.009 mSv, 0.06 mSv, 0.12 mSv, 0.09 mSv and 0.08 mSv. The participation in an international intercomparison sponsored by IAEA with simulated workplace fields validated the system. The monitoring system was successfully characterized in the ISO 21909 standard and in an IRD - the Brazilian Institute for Radioprotection and Dosimetry - technical regulation draft. Nowadays, the neutron individual system is in use by IRD for whole body individual monitoring of five institutions, which comprehend several activities. (author)

Review of present beta dosimetry problems in radiation protection; to day's answers and future trends

International Nuclear Information System (INIS)

Fracas, P.

1986-01-01

The large use of pure beta radionuclides needs to be develop beta dosimetry methods for radiation protection. The different types of present dosimetry assessments are reviewed. In all the cases the quantity to take into account is the absorbed dose rate in human tissus and more particularly in skin. In the case of point sources of known nature and activity this quantity can be worked out. This calculation is achieved either by incident beta spectrum analysis or theoretical considerations based on Kernel point. The absorbed dose rate can also be measured by extrapolation ionization chamber which characteristics and working are detailed here. All present survey meter were not initially planned for such a beta dosimetry, as this performed with the extrapolation ionization chamber which is taken here as a reference. So responses of usual dosimeters compared to this reference need to be estimated. Responses of personal film badges used in CEA, portable ionization chambers as babyline, pocket dosimeters SEQ7 and the thermoluminescent dosimeters TLD700 are exposed here. Results show that all these survey meters are not completely suitable for routine beta dosimetry. Consequently other operational dosimetry techniques have to be pursued. In particular some thermoluminescence dosimeters for instance boron diffused in surface layer and multi-elements, and furthermore Thermally Stimulated Exoelectron Emission (TSEE) and surface barrier detectors are described [fr

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-10-15

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

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

International Nuclear Information System (INIS)

Hadlock, D.E.

1987-06-01

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

Employment of MCNP in the study of TLDS 600 and 700 seeking the implementation of radiation beam characterization of BNCT facility at IEA-R1

International Nuclear Information System (INIS)

Cavalieri, Tassio Antonio

2013-01-01

Boron Neutron Capture Therapy, BNCT, is a bimodal radiotherapy procedure for cancer treatment. Its useful energy comes from a nuclear reaction driven by impinging thermal neutron upon Boron 10 atoms. A BNCT research facility has been constructed in IPEN at the IEA-R1 reactor, to develop studies in this area. One of its prime experimental parameter is the beam dosimetry which is nowadays made by using activation foils, for neutron measurements, and TLD 400, for gamma dosimetry. For mixed field dosimetry, the International Commission on Radiation Units and Measurements, ICRU, recommends the use of pair of detectors with distinct responses to the field components. The TLD 600/ TLD 700 pair meets this criteria, as the amount of 6 Li, a nuclide with high thermal neutron cross section, greatly differs in their composition. This work presents a series of experiments and simulations performed in order to implement the mixed field dosimetry based on the use of TLD 600/TLD 700 pair. It also intended to compare this mixed field dosimetric methodology to the one so far used by the BNCT research group of IPEN. The response of all TLDs were studied under irradiations in different irradiation fields and simulations, underwent by MCNP, were run in order to evaluate the dose contribution from each field component. Series of repeated irradiations under pure gamma field and mixed field neutron/gamma field showed differences in the TLD individual responses which led to the adoption of a Normalization Factor. It has allowed to overcome TLD selection. TLD responses due to different field components and spectra were studied. It has shown to be possible to evaluate the relative gamma/neutron fluxes from the relative responses observed in the two Regions of Interest, ROIs, from TLD 600 and TLD 700. It has also been possible to observe the TLD 700 response to neutron, which leads to a gamma dose overestimation when one follows the ICRU recommended mixed field dosimetric procedure. Dose

Employment of MCNP in the study of TLDS 600 and 700 seeking the implementation of radiation beam characterization of BNCT facility at IEA-R1; Emprego do MCNP no estudo dos TLDS 600 e 700 visando a implementacao da caracterizacao do feixe de irradiacao da instalacao de BNCT do IEA-R1

Energy Technology Data Exchange (ETDEWEB)

Cavalieri, Tassio Antonio

2013-07-01

Boron Neutron Capture Therapy, BNCT, is a bimodal radiotherapy procedure for cancer treatment. Its useful energy comes from a nuclear reaction driven by impinging thermal neutron upon Boron 10 atoms. A BNCT research facility has been constructed in IPEN at the IEA-R1 reactor, to develop studies in this area. One of its prime experimental parameter is the beam dosimetry which is nowadays made by using activation foils, for neutron measurements, and TLD 400, for gamma dosimetry. For mixed field dosimetry, the International Commission on Radiation Units and Measurements, ICRU, recommends the use of pair of detectors with distinct responses to the field components. The TLD 600/ TLD 700 pair meets this criteria, as the amount of {sup 6}Li, a nuclide with high thermal neutron cross section, greatly differs in their composition. This work presents a series of experiments and simulations performed in order to implement the mixed field dosimetry based on the use of TLD 600/TLD 700 pair. It also intended to compare this mixed field dosimetric methodology to the one so far used by the BNCT research group of IPEN. The response of all TLDs were studied under irradiations in different irradiation fields and simulations, underwent by MCNP, were run in order to evaluate the dose contribution from each field component. Series of repeated irradiations under pure gamma field and mixed field neutron/gamma field showed differences in the TLD individual responses which led to the adoption of a Normalization Factor. It has allowed to overcome TLD selection. TLD responses due to different field components and spectra were studied. It has shown to be possible to evaluate the relative gamma/neutron fluxes from the relative responses observed in the two Regions of Interest, ROIs, from TLD 600 and TLD 700. It has also been possible to observe the TLD 700 response to neutron, which leads to a gamma dose overestimation when one follows the ICRU recommended mixed field dosimetric procedure. Dose

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-08-15

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

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

International Nuclear Information System (INIS)

Rios, S.

1997-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1999-07-01

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

Program of TLD audits for quality control in radiotherapy

International Nuclear Information System (INIS)

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

1998-01-01

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

Design, fabrication, installation and shielding integrity testing of source storage container for automatic source movement system used in TLD calibration facility

International Nuclear Information System (INIS)

Subramanian, V.; Baskar, S.; Annalakshmi, O.; Jose, M.T.; Jayshree, C.P.; Choudry, Shreelatha

2012-01-01

A state-of-art TLD laboratory has been commissioned in January 2000 at Radiological Safety Division of Indira Gandhi Centre for Atomic Research (IGCAR). The laboratory provides personnel monitoring service to 2000 occupational workers from Indira Gandhi Centre for Atomic Research and Bhabha Atomic Research Centre facilities. The laboratory has been accredited by the Radiation Safety Systems Division (RSSD), Bhabha Atomic Research Centre (BARC) since year 2002. The laboratory has exclusive facility for the calibration of the TLD cards. As apart of accreditation procedure and taking into account of geometry effect, the dose rate at the card position is determined by the accreditation authorities by using graphite chamber (secondary or national standard instrument) and often re estimated by a condenser R meter (M/s Victoreen, Germany) by our laboratory. As per the regulatory requirement, the exposure protocols should be automated. Towards this an automatic source movement system has been augmented in the calibration facility. By using the system, the source will be brought to the irradiation position by pneumatically and exposures will be terminated by counter, timer and triggering system. To accomplish this task a lead container has been designed, fabricated and mounted at the beneath of the calibration table for the storage of source. As per the automation process, a lead container for the source storage has been designed and installed beneath to the Calibration Table. The container was designed to hold a 3Ci 137 Cs source, but present activity of the source is 1.2Ci. Hence, the shielding integrity was tested with higher active source (1.7Ci 60 Co). The dose rate measured outside on the circumference of the container at the middle of the source is found to be the same as calculated using QAD CGGP calculations. The top plug is so designed to avoid inadvertent upward movement of the source. Though, the shielding was not adequate on top of the top plug, however it does

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

International Nuclear Information System (INIS)

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

2016-10-01

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

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

International Nuclear Information System (INIS)

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

2011-01-01

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

Experimental determination of relative light conversion factors of TLD-100 for protons with energies from 2.0 to 9.0 MeV

International Nuclear Information System (INIS)

Schmidt, P.; Fellinger, J.; Henniger, J.; Huebner, K.

1988-01-01

The efficiency of thermoluminescent (TL) detectors to heavy charged particles is described by the so-called light conversion factor η. Relative light conversion factors for protons, alphas and heavier recoils are needed for the calculation of the neutron sensitivity of TL detectors. Such light conversion factors can be determined experimentally. In this paper a method is presented for the experimental determination of relative light conversion factors. Using the experimental arrangement described, relative light conversion factors for LiF material (TLD-100) for protons were determined. In LiF the relative main peak (peak V) efficiency is always lower than 1. It increases with increasing proton energy whereas the relative efficiency of the high temperature peak (peak VI) shows an opposite dependence on the proton energy. Relative light conversion factors for peak VI clearly exceed 1. (orig.)

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

Energy Technology Data Exchange (ETDEWEB)

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

1977-03-01

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

Efficacy of a Radiation Absorbing Shield in Reducing Dose to the Interventionalist During Peripheral Endovascular Procedures: A Single Centre Pilot Study

International Nuclear Information System (INIS)

Power, S.; Mirza, M.; Thakorlal, A.; Ganai, B.; Gavagan, L. D.; Given, M. F.; Lee, M. J.

2015-01-01

PurposeThis prospective pilot study was undertaken to evaluate the feasibility and effectiveness of using a radiation absorbing shield to reduce operator dose from scatter during lower limb endovascular procedures.Materials and MethodsA commercially available bismuth shield system (RADPAD) was used. Sixty consecutive patients undergoing lower limb angioplasty were included. Thirty procedures were performed without the RADPAD (control group) and thirty with the RADPAD (study group). Two separate methods were used to measure dose to a single operator. Thermoluminescent dosimeter (TLD) badges were used to measure hand, eye, and unshielded body dose. A direct dosimeter with digital readout was also used to measure eye and unshielded body dose. To allow for variation between control and study groups, dose per unit time was calculated.ResultsTLD results demonstrated a significant reduction in median body dose per unit time for the study group compared with controls (p = 0.001), corresponding to a mean dose reduction rate of 65 %. Median eye and hand dose per unit time were also reduced in the study group compared with control group, however, this was not statistically significant (p = 0.081 for eye, p = 0.628 for hand). Direct dosimeter readings also showed statistically significant reduction in median unshielded body dose rate for the study group compared with controls (p = 0.037). Eye dose rate was reduced for the study group but this was not statistically significant (p = 0.142).ConclusionInitial results are encouraging. Use of the shield resulted in a statistically significant reduction in unshielded dose to the operator’s body. Measured dose to the eye and hand of operator were also reduced but did not reach statistical significance in this pilot study

Efficacy of a Radiation Absorbing Shield in Reducing Dose to the Interventionalist During Peripheral Endovascular Procedures: A Single Centre Pilot Study

Energy Technology Data Exchange (ETDEWEB)

Power, S.; Mirza, M.; Thakorlal, A.; Ganai, B.; Gavagan, L. D.; Given, M. F.; Lee, M. J., E-mail: mlee@rcsi.ie [Beaumont Hospital, Imaging and Interventional Radiology Department (Ireland)

2015-06-15

PurposeThis prospective pilot study was undertaken to evaluate the feasibility and effectiveness of using a radiation absorbing shield to reduce operator dose from scatter during lower limb endovascular procedures.Materials and MethodsA commercially available bismuth shield system (RADPAD) was used. Sixty consecutive patients undergoing lower limb angioplasty were included. Thirty procedures were performed without the RADPAD (control group) and thirty with the RADPAD (study group). Two separate methods were used to measure dose to a single operator. Thermoluminescent dosimeter (TLD) badges were used to measure hand, eye, and unshielded body dose. A direct dosimeter with digital readout was also used to measure eye and unshielded body dose. To allow for variation between control and study groups, dose per unit time was calculated.ResultsTLD results demonstrated a significant reduction in median body dose per unit time for the study group compared with controls (p = 0.001), corresponding to a mean dose reduction rate of 65 %. Median eye and hand dose per unit time were also reduced in the study group compared with control group, however, this was not statistically significant (p = 0.081 for eye, p = 0.628 for hand). Direct dosimeter readings also showed statistically significant reduction in median unshielded body dose rate for the study group compared with controls (p = 0.037). Eye dose rate was reduced for the study group but this was not statistically significant (p = 0.142).ConclusionInitial results are encouraging. Use of the shield resulted in a statistically significant reduction in unshielded dose to the operator’s body. Measured dose to the eye and hand of operator were also reduced but did not reach statistical significance in this pilot study.

ICRP-26 and skin contamination

International Nuclear Information System (INIS)

Finnigan, T.; Huda, W.; Newbery, G.R.

1979-01-01

The experience of dealing with skin contamination incidents at The Radiochemical Centre over a 3-year period is presented. Data are given for the primary isotopes involved, the duration of skin contamination, and the skin doses that arise from these incidents. The methods employed in performing dosimetry for skin contamination are discussed and examples involving the isotopes carbon-14 and indium-111 are described. For skin contamination incidents, the mode of penetration of the activity into skin is normally not known and this can be of major significance for the final skin dose estimate. The operational health physics difficulties encountered in complying with both ICRP-26 and UK legislation for skin contamination are considered. In the event of multiple exposure (i.e. skin doses calculated from whole body film badges, extremity TLD dose meters and skin contamination) there is ambiguity in the precise meaning of the skin dose. The usefulness of Derived Working Levels is also discussed. Experience at The Radiochemical Centre has shown that good plant design, proper training and prompt action in dealing with contamination incidents ensures that overexposures to skin from accidental contamination are rare occurrences. (author)

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

International Nuclear Information System (INIS)

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

1996-01-01

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

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

International Nuclear Information System (INIS)

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

1987-01-01

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

The Battle for Critical Internet Resources: South America vs. Amazon.com, Inc.

OpenAIRE

Patricia Vargas-Leon; Andreas Kuehn

2015-01-01

Purpose – To analyze the controversy about the allocation of critical Internet resources generated by ICANN's new gTLD program with a particular focus on the .AMAZON TLD. Methodology/approach/design – This article presents an exploratory case study about the .AMAZON controversy. The initial analysis of this ongoing research is based on data collected from various reports and media coverage on ICANN's new gTLD policy. The article draws from political economy theory to analyze disputes about...

Experimental calibration and determination of the relative response for Lif: Mg, Ti(TLD-100) dosemeters at 60Co gamma and 60 kVp X-ray energies

International Nuclear Information System (INIS)

Marco, M.L.; Gonzalez, L.; Delgado, V.; Vano, E.; Moran, P.

1985-01-01

The thermoluminescence efficiency of LiF: Mg, Ti (TLD-100) dosemeters has been determined for photon beams from 60 Co gamma rays and 60 kVp X-rays. It has been proven that light yield varies as a function of the photon energy. An experiment was performed using an X-ray beam whose spectrum has been determined by an X-ray fluorescence method. This enabled a direct calculation of the absorbed doses in the T1 material for the different operation conditions. These values and the experimental ones from measuring T1 intensities have been used to obtain the efficiency for energy X-ray spectrum. From the above values, the dosemeter T1 response, relative to 60 Co, has been evaluated. (author)

Experimental determination of relative light conversion factors of TLD-100 for protons with energies from 2.0 to 9.0 MeV

International Nuclear Information System (INIS)

Schmidt, P.; Fellinger, J.; Huebner, K.; Henniger, J.

1985-01-01

Relative light conversion factors (RLCF) for heavy charged particles (protons, deuterons, recoils) are needed for the calculation of the neutron sensitivity of thermoluminescent (TL) detectors. Such light conversion factors can be determined experimentally. A method is represented for the experimental determination of RLCF. The described experimental facility gives the possibility of irradiation of different luminophor samples with heavy charged particles and flux determination and particle spectrometry at the same time. For the determination of RLCF the doses are needed which are applicated at the irradiation with heavy charged particles and gamma radiation, respectively, and the according detector readings at the TL evaluation. The problems arising at the dose determination are discussed. With this experimental facility the RLCF for TLD-100 for protons were determined. The relative light conversion factors determined according to the light sum method as well as the peak height method are summarizinhly represented and discussed. Furthermore a comparison of the glow curves is made after gamma and proton irradiation

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

International Nuclear Information System (INIS)

Maiello, M.

1994-11-01

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

Bisphenol diglycidyl ethers and bisphenol A and their hydrolysis in drinking water.

Science.gov (United States)

Lane, R F; Adams, C D; Randtke, S J; Carter, R E

2015-04-01

Epoxy coatings are commonly used to protect the interior (and exterior) surfaces of water mains and storage tanks and can be used on the interior surfaces of water pipes in homes, hospitals, hotels, and other buildings. Common major components of epoxies include bisphenols, such as bisphenol A (BPA) or bisphenol F (BPF), and their reactive prepolymers, bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE), respectively. There currently are health concerns about the safety of BPA and BPF due to known estrogenic effects. Determination of key bisphenol leachates, development of a hydrolysis model, and identification of stable hydrolysis products will aid in assessment of human bisphenol exposure through ingestion of drinking water. Liquid chromatography/mass spectrometry (LC/MS/MS) was used for quantitation of key analytes, and a pseudo-first order kinetic approach was used for modeling. In fill-and-dump studies on epoxy-coated pipe specimens, BADGE and a BPA-like compound were identified as leachates. The BADGE hydrolysis model predicts BADGE half-lives at pH 7 and 15, 25, 35, and 40 °C to be 11, 4.6, 2.0, and 1.4 days respectively; the BFDGE half-life was 5 days at pH 7 and 25 °C. The two identified BADGE hydrolysis products are BADGE-H2O and BADGE 2H2O, with BADGE 2H2O being the final end product under the conditions studied. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dose assessment of the patient and the helper in emergency head computed tomography

International Nuclear Information System (INIS)

Chang, Rong-Chou; Yu, Cheng-Ching; Hsu, Fang-Yuh; Chen, Tou-Rong; Hsu, Shih-Ming; Tyan, Yeu-Sheng

2011-01-01

Computed Tomography (CT) becomes more and more important and is frequently used in modern diagnostic techniques. CT offers an effective diagnosis on lesion and pathology; however, it also delivers a radiation dose to patients. Besides, in some special emergency cases, the patient may require someone to help him in the examination room to perform the head CT, due to the patient lost intellectual and operational capacity. This study evaluated the delivered radiation dose and the risk of radiation-induced cancer for the patient and for the helper after carrying out the emergent head CT examination. A Rando phantom with thermoluminescent dosimeter (TLD) chips inside relevant organs was used to simulate the patient during head CT examination. An effective dose of 2.06 ± 0.16 mSv and 1.46 ± 0.07 mSv without and with wearing the lead apron were found respectively, considering ICRP 60 recommendation. ICRP 103 recommendations the readings would have been 1.29 ± 0.15 mSv and 0.71 ± 0.04 mSv. The effective dose determined from the dose-length product (DLP) method (2.19 mSv) was similar to the value (2.06 ± 0.16 mSv) estimated by TLD method considering the ICRP 60 recommendation (without lead apron). Assuming a 5% total risk for fatal cancer per Sv in the general population, risk of radiation-induced cancer for patients were 1.03 × 10 −2 % (without lead apron) and 7.80 × 10 −3 % (with lead apron) for ICRP 60, and were 6.45 × 10 −3 % (without lead apron) and 3.55 × 10 −3 % (with lead apron) for ICRP 103. The dose received by the helper was assessed by wearing a personal badge. The helper during emergent head CT examination may receive a personal dose equivalent (H p (10)) of 19.36 ± 5.89 μSv and 138.81 ± 101.28 μSv with and without lead apron, respectively, at distance of 0.3–1 m from the center of CT scanner. Based on the observed dose reduction of a factor of 7.17 we recommend that helpers wear lead apron in the CT examination room.

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

Science.gov (United States)

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

2016-03-01

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

Collecting location-based voice messages on a TalkingBadge

DEFF Research Database (Denmark)

Hansen, John Paulin; Glenstrup, Arne John; Wusheng, Wang

2012-01-01

and specific enough to distinguish between zones located just 20 meters apart. Finally, we played digitized voice messages to 11 participants walking into a zone. They received most of the messages well, but a majority of their comments were negative, expressing concerns for the potential infringement...... of privacy. We conclude that location specific audio messaging works from a technical perspective, but requires careful consideration of social comfort....

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

International Nuclear Information System (INIS)

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

2014-08-01

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

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

International Nuclear Information System (INIS)

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

2013-01-01

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

Risk assessment of topically applied products

DEFF Research Database (Denmark)

Søborg, Tue; Basse, Line Hollesen; Halling-Sørensen, Bent

2007-01-01

The human risk of harmful substances in semisolid topical dosage forms applied topically to normal skin and broken skin, respectively, was assessed. Bisphenol A diglycidyl ether (BADGE) and three derivatives of BADGE previously quantified in aqueous cream and the UV filters 3-BC and 4-MBC were used...... as model compounds. Tolerable daily intake (TDI) values have been established for BADGE and derivatives. Endocrine disruption was chosen as endpoint for 3-BC and 4-MBC. Skin permeation of the model compounds was investigated in vitro using pig skin membranes. Tape stripping was applied to simulate broken...... parameters for estimating the risk. The immediate human risk of BADGE and derivatives in topical dosage forms was found to be low. However, local treatment of broken skin may lead to higher exposure of BADGE and derivatives compared to application to normal skin. 3-BC permeated skin at higher flux than 4-MBC...

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

Directory of Open Access Journals (Sweden)

Farhood B.

2016-06-01

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

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.

Adaptive and accelerated tracking-learning-detection

Science.gov (United States)

Guo, Pengyu; Li, Xin; Ding, Shaowen; Tian, Zunhua; Zhang, Xiaohu

2013-08-01

An improved online long-term visual tracking algorithm, named adaptive and accelerated TLD (AA-TLD) based on Tracking-Learning-Detection (TLD) which is a novel tracking framework has been introduced in this paper. The improvement focuses on two aspects, one is adaption, which makes the algorithm not dependent on the pre-defined scanning grids by online generating scale space, and the other is efficiency, which uses not only algorithm-level acceleration like scale prediction that employs auto-regression and moving average (ARMA) model to learn the object motion to lessen the detector's searching range and the fixed number of positive and negative samples that ensures a constant retrieving time, but also CPU and GPU parallel technology to achieve hardware acceleration. In addition, in order to obtain a better effect, some TLD's details are redesigned, which uses a weight including both normalized correlation coefficient and scale size to integrate results, and adjusts distance metric thresholds online. A contrastive experiment on success rate, center location error and execution time, is carried out to show a performance and efficiency upgrade over state-of-the-art TLD with partial TLD datasets and Shenzhou IX return capsule image sequences. The algorithm can be used in the field of video surveillance to meet the need of real-time video tracking.

Extremely secure identification documents

International Nuclear Information System (INIS)

Tolk, K.M.; Bell, M.

1997-09-01

The technology developed in this project uses biometric information printed on the document and public key cryptography to ensure that an adversary cannot issue identification documents to unauthorized individuals or alter existing documents to allow their use by unauthorized individuals. This process can be used to produce many types of identification documents with much higher security than any currently in use. The system is demonstrated using a security badge as an example. This project focused on the technologies requiring development in order to make the approach viable with existing badge printing and laminating technologies. By far the most difficult was the image processing required to verify that the picture on the badge had not been altered. Another area that required considerable work was the high density printed data storage required to get sufficient data on the badge for verification of the picture. The image processing process was successfully tested, and recommendations are included to refine the badge system to ensure high reliability. A two dimensional data array suitable for printing the required data on the badge was proposed, but testing of the readability of the array had to be abandoned due to reallocation of the budgeted funds by the LDRD office

The Battle for Critical Internet Resources: South America vs. Amazon.com, Inc.

Directory of Open Access Journals (Sweden)

Patricia Vargas-Leon

2015-04-01

Full Text Available Purpose – To analyze the controversy about the allocation of critical Internet resources generated by ICANN's new gTLD program with a particular focus on the .AMAZON TLD. Methodology/approach/design – This article presents an exploratory case study about the .AMAZON controversy. The initial analysis of this ongoing research is based on data collected from various reports and media coverage on ICANN's new gTLD policy. The article draws from political economy theory to analyze disputes about critical Internet resources. Findings – This article discusses preliminary findings of the .AMAZON case, a contested prime example in ICANN's efforts to extend the Internet's domain name space. Practical implications – The findings may inform related controversies in the gTLD program and contribute to a differentiated understanding of CIR allocation in Internet governance, and respective policy-making. Originality/value – The value of this article is the specific discussion of the .AMAZON case in the larger context of ICANN's new gTLD program, and its analysis that describes the controversy from a property rights perspective.

The Battle for Critical Internet Resources: South America vs. Amazon.com, Inc.

Directory of Open Access Journals (Sweden)

Patricia Vargas-Leon

2015-05-01

Full Text Available Purpose – To analyze the controversy about the allocation of critical Internet resources generated by ICANN's new gTLD program with a particular focus on the .AMAZON TLD. Methodology/approach/design – This article presents an exploratory case study about the .AMAZON controversy. The initial analysis of this ongoing research is based on data collected from various reports and media coverage on ICANN's new gTLD policy. The article draws from political economy theory to analyze disputes about critical Internet resources. Findings – This article discusses preliminary findings of the .AMAZON case, a contested prime example in ICANN's efforts to extend the Internet's domain name space. Practical implications – The findings may inform related controversies in the gTLD program and contribute to a differentiated understanding of CIR allocation in Internet governance, and respective policy-making. Originality/value – The value of this article is the specific discussion of the .AMAZON case in the larger context of ICANN's new gTLD program, and its analysis that describes the controversy from a property rights perspective.

The Seibersdorf TL Personnel Dosimetry Service

Energy Technology Data Exchange (ETDEWEB)

Duftschmid, K E [Oesterreichisches Forschungszentrum Seibersdorf GmbH (Austria)

1994-11-01

Since 1976 the Department for Radiation Protection of the Austrian Research Centre Seibersdorf has been operating a TLD Personnel Monitoring Service, which presently covers about 18,000 radiation workers in Austria, with monthly monitoring periods. We have been the first accredited monitoring service in Europe, which fully converted from film dosimetry to TLD. From the beginning up to 1991 the service was based on three automated TLD systems Model 2271 from HARSHAW, USA. After extensive testing and comparisons, since almost four years now, the monitoring service has been operating on two HARSHAW 8800 systems, which are described in more detail below. (author).

The Seibersdorf TL Personnel Dosimetry Service

International Nuclear Information System (INIS)

Duftschmid, K.E.

1994-11-01

Since 1976 the Department for Radiation Protection of the Austrian Research Centre Seibersdorf has been operating a TLD Personnel Monitoring Service, which presently covers about 18,000 radiation workers in Austria, with monthly monitoring periods. We have been the first accredited monitoring service in Europe, which fully converted from film dosimetry to TLD. From the beginning up to 1991 the service was based on three automated TLD systems Model 2271 from HARSHAW, USA. After extensive testing and comparisons, since almost four years now, the monitoring service has been operating on two HARSHAW 8800 systems, which are described in more detail below. (author)

Proximity credentials: A survey

International Nuclear Information System (INIS)

Wright, L.J.

1987-04-01

Credentials as a means of identifying individuals have traditionally been a photo badge and more recently, the coded credential. Another type of badge, the proximity credential, is making inroads in the personnel identification field. This badge can be read from a distance instead of being veiewed by a guard or inserted into a reading device. This report reviews proximity credentials, identifies the companies marketing or developing proximity credentials, and describes their respective credentials. 3 tabs

Angular and radial dependence of the energy response factor for LiF-TLD micro-rods in 125I permanent implant source

International Nuclear Information System (INIS)

Mobit, P.; Badragan, I.

2006-01-01

EGSnrc Monte Carlo simulations were used to calculate the angular and radial dependence of the energy response factor for LiF-thermoluminescence dosemeters (TLDs) irradiated with a commercially available 125 I permanent brachytherapy source. The LiF-TLDs were modelled as cylindrical micro-rods of length 6 mm and with diameters of 1 mm and 5 mm. The results show that for a LiF-TLD micro-rod of 1 mm diameter, the energy response relative to 60 Co gamma rays is 1.406 ± 0.3% for a polar angle of 90 deg. and radial distance of 1.0 cm. When the diameter of the micro-rod is increased from 1 to 5 mm, the energy response decreases to 1.32 ± 0.3% at the same point. The variation with position of the energy response factor is not >5% in a 6 cm x 6 cm x 6 cm calculation grid for the 5 mm diameter micro-rod. The results show that there is a change in the photon spectrum with angle and radial distance, which causes the variation of the energy response. (authors)

Instrumentation in thermoluminescence dosimetry

International Nuclear Information System (INIS)

Julius, H.W.

1986-01-01

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

Coordinated research efforts for establishing an international radiotherapy dose intercomparison service based on the alanine/ESR system

International Nuclear Information System (INIS)

Nette, H.P.; Onori, S.; Fattibene, P.; Regulla, D.; Wieser, A.

1993-01-01

The IAEA has long been active in the field of high-dose standardization. An International Dose Assurance Service (IDAS) was established based on alanine/ESR dosimetry. This service operates over the range of 100 Gy to 100 kGy and is directed towards industrial radiation processing in IAEA member states. It complements the IAEA/WHO TLD postal dose intercomparison service for dose assurance in hospital radiotherapy departments. Experience with the alanine high dose service suggests that the alanine dosimeter might provide superior performance to TLD in the therapy dose range. Preliminary test measurements with the participation of GSF/Germany, Istituto Superiore di Sanita/Italy (both providing alanine dosimeters and their evaluation) and IAEA (providing reference irradiations) seems to justify research efforts through an IAEA Coordinated Research Programme (CRP). This CRP, entitled ''Therapy Level Dosimetry with the Alanine/ESR System'' is presently under set-up. It will include general work common to all assigned/potential contract holders as well as some specific research topics in accordance to individual proposals of each participant. (author)

Development and characterization of two-component albedo based neutron individual monitoring system using thermoluminescent detectors; Desenvolvimento e caracterizacao de um sistema de monitoracao individual de neutrons tipo albedo de duas componentes usando detectores termoluminescentes

Energy Technology Data Exchange (ETDEWEB)

Martins, Marcelo Marques

2008-07-01

A TLD-albedo based two-component neutron individual monitoring system was developed and characterized in this work. The monitor consists of a black plastic holder, an incident neutron boron loaded shield, a moderator polyethylene body (to increase its response), two pairs of TLD-600 and TLD-700 (one pair to each component) and an adjustable belt. This monitoring system was calibrated in thermal neutron fields and in 70 keV, 144 keV, 565 keV, 1.2 MeV and 5 MeV monoenergetic neutron fields. In addition, it was calibrated in {sup 252C}f(D{sub 2}O), {sup 252}Cf, {sup 241}Am-B, {sup 241}Am-Be and {sup 238}Pu-Be source fields. For the latter, the lower detection levels are, respectively, 0.009 mSv, 0.06 mSv, 0.12 mSv, 0.09 mSv and 0.08 mSv. The participation in an international intercomparison sponsored by IAEA with simulated workplace fields validated the system. The monitoring system was successfully characterized in the ISO 21909 standard and in an IRD - the Brazilian Institute for Radioprotection and Dosimetry - technical regulation draft. Nowadays, the neutron individual system is in use by IRD for whole body individual monitoring of five institutions, which comprehend several activities. (author)

Badge of Honor or Scarlet Letter?

DEFF Research Database (Denmark)

Zunino, Diego; Dushnitsky, Gary; Van Praag, Mirjam

Research shows that most ventures fail, yet it has devoted limited attention to the consequences of entrepreneurs’ past failure for investors’ decisions. Our motivating insight is that failure can be due to bad luck, lack of skill or both. Therefore, failure conveys ambiguous information about...... of skill, however, is not discounted. The findings indicate no discount of failure based on the “failed” label only. Overall, our analysis sheds light on the rationality of investors. In a world where entrepreneurial failure is prevalent, we find that investors are sensitive to its core drivers: luck...

UV dosimetry in Antarctica (Baia Terranova): analysis of data from polysulphone films and GUV 511 radiometer

Science.gov (United States)

Mariutti, Gianni F.; Bortolin, Emanuela; Polichetti, Alessandro; Anav, Andrea; Casale, Giuseppe R.; Di Menno, Massimo; Rafanelli, Claudio

2003-11-01

This paper shows the results of measurements carried out in November 2002 in the Italian Antarctic Base of Baia Terranova (74.07°S, 164.08°E) to test polysulphone film badges as possible UV personal dosimeters in such extreme environmental conditions. In the Italian Antarctic Base a multichannel radiometer GUV 511 (Biospherical Inc.) is routinely used by the Italian National Research Council (CNR) for UV irradiance at sea level. This instrument measures the intensity of the solar UV spectrum at four different wavelengths: 305, 320, 340, 380 nm, respectively. Data obtained from polysulphone badges exposed in the horizontal and the vertical configurations during diverse time lapses of the day, and from polysulphone badges worn by three volunteers of the base staff during several outdoors activities, have been compared with the irradiance data calculated from the measured values of GUV 511. A preliminary analysis of the whole data, also in the light of other recorded atmospheric and climatic parameters, shows a reasonable consistency. As also shown by previous measurements, carried out in June 2002 in the locality of Ny Alesund (Svalbard -- Artic Region), the calibration of the above mentioned personal dosimeters by means of another instrument operating in the same locality is a crucial step. Further work is required to demonstrate this approach is suitable for an acceptable evaluation of personal radiant exposures.

Volume 10 No. 2 February 2010 2152 DETERMINATION OF ...

African Journals Online (AJOL)

2010-02-02

Feb 2, 2010 ... lacquered with epoxyphenolic or organosol resins. BADGE concentrations were ... Key words: Epoxyphenolic resin, BADGE, Can, Food ..... monomers and additives used in the manufacture of plastics and coatings intended to ...

Technical Area 55 Entry Control System (ECS)

International Nuclear Information System (INIS)

Beaumont, A.; Brundige, E.; DesJardin, R.; Rivera, R.

1984-01-01

The exchange badge system which was used at the Plutonium Facility located in Technical Area 55 was replaced on a trial basis with an automated Entry Control System. As a result of the success of the trial system, a new system incorporating expanded features and increased reliability is being implemented. The new Entry Control System incorporates several features not previously available in relatively inexpensive entry systems. The reliability of the system is enhanced by redundant microprocessors incorporating bubble memory for nonvolatile storage of the system data base. The badge readers incorporate dual communication lines to two different controllers to further increase the total system reliability

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

Energy Technology Data Exchange (ETDEWEB)

Gomez Ros, J M; Delgado, A

1989-07-01

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

Numerical analysis of thermoluminescence glow curves

International Nuclear Information System (INIS)

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

1989-01-01

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

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

International Nuclear Information System (INIS)

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

2013-01-01

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

A global lightning parameterization based on statistical relationships among environmental factors, aerosols, and convective clouds in the TRMM climatology

Science.gov (United States)

Stolz, Douglas C.; Rutledge, Steven A.; Pierce, Jeffrey R.; van den Heever, Susan C.

2017-07-01

The objective of this study is to determine the relative contributions of normalized convective available potential energy (NCAPE), cloud condensation nuclei (CCN) concentrations, warm cloud depth (WCD), vertical wind shear (SHEAR), and environmental relative humidity (RH) to the variability of lightning and radar reflectivity within convective features (CFs) observed by the Tropical Rainfall Measuring Mission (TRMM) satellite. Our approach incorporates multidimensional binned representations of observations of CFs and modeled thermodynamics, kinematics, and CCN as inputs to develop approximations for total lightning density (TLD) and the average height of 30 dBZ radar reflectivity (AVGHT30). The results suggest that TLD and AVGHT30 increase with increasing NCAPE, increasing CCN, decreasing WCD, increasing SHEAR, and decreasing RH. Multiple-linear approximations for lightning and radar quantities using the aforementioned predictors account for significant portions of the variance in the binned data set (R2 ≈ 0.69-0.81). The standardized weights attributed to CCN, NCAPE, and WCD are largest, the standardized weight of RH varies relative to other predictors, while the standardized weight for SHEAR is comparatively small. We investigate these statistical relationships for collections of CFs within various geographic areas and compare the aerosol (CCN) and thermodynamic (NCAPE and WCD) contributions to variations in the CF population in a partial sensitivity analysis based on multiple-linear regression approximations computed herein. A global lightning parameterization is developed; the average difference between predicted and observed TLD decreases from +21.6 to +11.6% when using a hybrid approach to combine separate approximations over continents and oceans, thus highlighting the need for regionally targeted investigations in the future.

Impact of a smoking ban in hospitality venues on second hand smoke exposure: a comparison of exposure assessment methods.

Science.gov (United States)

Rajkumar, Sarah; Huynh, Cong Khanh; Bauer, Georg F; Hoffmann, Susanne; Röösli, Martin

2013-06-04

In May 2010, Switzerland introduced a heterogeneous smoking ban in the hospitality sector. While the law leaves room for exceptions in some cantons, it is comprehensive in others. This longitudinal study uses different measurement methods to examine airborne nicotine levels in hospitality venues and the level of personal exposure of non-smoking hospitality workers before and after implementation of the law. Personal exposure to second hand smoke (SHS) was measured by three different methods. We compared a passive sampler called MoNIC (Monitor of NICotine) badge, to salivary cotinine and nicotine concentration as well as questionnaire data. Badges allowed the number of passively smoked cigarettes to be estimated. They were placed at the venues as well as distributed to the participants for personal measurements. To assess personal exposure at work, a time-weighted average of the workplace badge measurements was calculated. Prior to the ban, smoke-exposed hospitality venues yielded a mean badge value of 4.48 (95%-CI: 3.7 to 5.25; n = 214) cigarette equivalents/day. At follow-up, measurements in venues that had implemented a smoking ban significantly declined to an average of 0.31 (0.17 to 0.45; n = 37) (p = 0.001). Personal badge measurements also significantly decreased from an average of 2.18 (1.31-3.05 n = 53) to 0.25 (0.13-0.36; n = 41) (p = 0.001). Spearman rank correlations between badge exposure measures and salivary measures were small to moderate (0.3 at maximum). Nicotine levels significantly decreased in all types of hospitality venues after implementation of the smoking ban. In-depth analyses demonstrated that a time-weighted average of the workplace badge measurements represented typical personal SHS exposure at work more reliably than personal exposure measures such as salivary cotinine and nicotine.

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

International Nuclear Information System (INIS)

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

1979-01-01

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