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

International Nuclear Information System (INIS)

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

2016-01-01

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

Comparative study of different Al{sub 2}O{sub 3}:C dosimeters using OSL technique for dosimetry on Volumetric Modulated Arc Radiotherapy Treatment (VMAT); Estudo comparativo de diferentes dosimetros de Al{sub 2}O{sub 3}:C pela tecnica OSL na dosimetria de tratamentos Radioterapicos por Arco Modulado Volumetrico (VMAT)

Energy Technology Data Exchange (ETDEWEB)

Villani, Daniel; Campos, LetIcia L., E-mail: dvillani@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Mancini, Anselmo; Haddad, Cecilia M.K. [Hospital Sirio-Libanes, Sao Paulo, SP (Brazil). Centro de Radioterapia

2016-07-01

In modern radiotherapy, the VMAT technique has become a successful treatment alternative. Due to its complexity, a quality assurance program must be established by evaluating, among other items, the dosimetric factors. This paper aims to compare the performance between the OSL aluminum oxide (Al{sub 2}O{sub 3}:C) nanoDot™ dosimeters (Inlight™ system) manufactured by Landauer Inc. and TLD-500 Al{sub 2}O{sub 3}:C dosimeters manufactured by Rexon™ for VMAT dosimetry using an anthropomorphic phantom. The results showed that both type of Al{sub 2}O{sub 3}:C dosimeters presented good repeatability and agreement between the doses measured and calculated by planning system. However, the need of sophisticated readers to OSL analysis of the TLD-500, turns it less practical for routine usage, comparing to Inlight™ system. (author)

Intercomparison of dispersed radiation readings among film dosimetry, electronic and OSL with X-rays for low dose; Intercomparacion de lecturas de radiacion dispersa entre dosimetria film, electronica y OSL con rayos X para dosis bajas

Energy Technology Data Exchange (ETDEWEB)

Andisco, D. [Universidad de Buenos Aires, Facultad de Medicina, Paraguay 2155, C1121AAA Buenos Aires (Argentina); Blanco, S. [CONICET, Saavedra 15, C1083ACA Buenos Aires (Argentina); Bourel, V.; Schmidt, L. [Universidad Favaloro, Facultad de Ciencias e Ingenieria, Solis 453, C1078AAI, Buenos Aires (Argentina); Di Risio, C., E-mail: dandisco@fmed.uba.ar [Universidad de Belgrano, Facultad de Ingenieria, Zabala 1837, C1426DQG, Buenos Aires (Argentina)

2014-08-15

One of the personal dosimetry methods more used for several decades is the dosimetry type film, characterized to possess readings with certain margin of trust. Today other methods exist that many times are presupposed more reliable due to the nature of the detection like the electronic dosimeters or the OSL (Optically Stimulated Luminescence) dosimetry. With the purpose of comparing different methods and to can determining the existent differences among each method has been carried out an intercomparison assay. The different dosimeters have been exposed to dispersed radiation generated by a Hemodynamics equipment of the type -arch in C- and a dispersing system of the primary beam. Film dosimeters have been used; OSL (In Light), OSL (Nano Dots) and Electronic with the purpose of knowing and to valorize the existent differences among its readings. Always, the intercomparison exercises have demonstrated to be an useful tool when establishing the measurement capacity and the quality of the results emitted by the laboratories of personal dosimetry services. Also, this type of assays allows obtaining quality indicators of the laboratory performance and they are habitual part of the procedures for accreditation of the same ones. The Optically Stimulated Luminescence is a technology that has grown in Argentina so much in the area of personal dosimetry as in dosimetry in vivo (radiotherapy area). In this intercomparison study, the answers corresponding to each technology were looked for oneself irradiation of the disperse type, that is to say, of very low energy. (Author)

Intercomparison of dispersed radiation readings among film dosimetry, electronic and OSL with X-rays for low dose

International Nuclear Information System (INIS)

Andisco, D.; Blanco, S.; Bourel, V.; Schmidt, L.; Di Risio, C.

2014-08-01

One of the personal dosimetry methods more used for several decades is the dosimetry type film, characterized to possess readings with certain margin of trust. Today other methods exist that many times are presupposed more reliable due to the nature of the detection like the electronic dosimeters or the OSL (Optically Stimulated Luminescence) dosimetry. With the purpose of comparing different methods and to can determining the existent differences among each method has been carried out an intercomparison assay. The different dosimeters have been exposed to dispersed radiation generated by a Hemodynamics equipment of the type -arch in C- and a dispersing system of the primary beam. Film dosimeters have been used; OSL (In Light), OSL (Nano Dots) and Electronic with the purpose of knowing and to valorize the existent differences among its readings. Always, the intercomparison exercises have demonstrated to be an useful tool when establishing the measurement capacity and the quality of the results emitted by the laboratories of personal dosimetry services. Also, this type of assays allows obtaining quality indicators of the laboratory performance and they are habitual part of the procedures for accreditation of the same ones. The Optically Stimulated Luminescence is a technology that has grown in Argentina so much in the area of personal dosimetry as in dosimetry in vivo (radiotherapy area). In this intercomparison study, the answers corresponding to each technology were looked for oneself irradiation of the disperse type, that is to say, of very low energy. (Author)

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)

Development of nano-sized α-Al2O3:C films for application in digital radiology

International Nuclear Information System (INIS)

Silva, Edna C.

2011-01-01

Ceramic materials are widely used as sensors for ionizing radiation. In nuclear applications, the alpha-alumina doped with carbon (α-Al 2 O 3 :C) is the most widely ceramic used because of its excellent optically stimulated luminescence (OSL) and thermoluminescent (TL) properties applied to detection of ionizing radiation. Another application of OSL and TL materials are in Digital Radiography, with ceramic/polymeric film composites. Recently, Computed Radiography (CR) devices based on OSL materials are replacing the old conventional film radiography. In this study we investigate the thermoluminescence of nano-sized α-Al 2 O 3 samples doped with different percentages of carbon, sintered in reducing atmospheres at temperatures ranging from 1300 to 1750 deg C. The results indicate that the nano-sized α-Al 2 O 3 :C materials have a luminescent response that could be due to both OSL and RPL properties, but without application to radiation dosimetry. Moreover, the results indicate that micro-sized α-Al 2 O 3 :C, doped with 0.5% carbon, and nano-sized ones doped with 2% of carbon, present thermoluminescent signal around 30 to 100 times the TL output signal of commercial TLD-100, the most used TL dosimeter in the world. The results indicate that these ceramic nano-particles have great potential for use in Digital Radiography based on thermoluminescent film imaging, being able to provide image resolutions much higher than the micro-sized α-Al 2 O 3 :C, in view of their improved resolution provided by nano-particulates. (author)

Development of nano-sized {alpha}-Al{sub 2}O{sub 3}:C films for application in digital radiology

Energy Technology Data Exchange (ETDEWEB)

Silva, Edna C., E-mail: edca@cdtn.b [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte (Brazil). Dept. de Engenharia Nuclear; Fontainha, Crissia C. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte (Brazil). Dept. de Propedeutica Complemetar; Oliveira, Vitor H.; Ferraz, Wilmar B.; Faria, Luiz O. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2011-07-01

Ceramic materials are widely used as sensors for ionizing radiation. In nuclear applications, the alpha-alumina doped with carbon ({alpha}-Al{sub 2}O{sub 3}:C) is the most widely ceramic used because of its excellent optically stimulated luminescence (OSL) and thermoluminescent (TL) properties applied to detection of ionizing radiation. Another application of OSL and TL materials are in Digital Radiography, with ceramic/polymeric film composites. Recently, Computed Radiography (CR) devices based on OSL materials are replacing the old conventional film radiography. In this study we investigate the thermoluminescence of nano-sized {alpha}-Al{sub 2}O{sub 3} samples doped with different percentages of carbon, sintered in reducing atmospheres at temperatures ranging from 1300 to 1750 deg C. The results indicate that the nano-sized {alpha}-Al{sub 2}O{sub 3}:C materials have a luminescent response that could be due to both OSL and RPL properties, but without application to radiation dosimetry. Moreover, the results indicate that micro-sized {alpha}-Al{sub 2}O{sub 3}:C, doped with 0.5% carbon, and nano-sized ones doped with 2% of carbon, present thermoluminescent signal around 30 to 100 times the TL output signal of commercial TLD-100, the most used TL dosimeter in the world. The results indicate that these ceramic nano-particles have great potential for use in Digital Radiography based on thermoluminescent film imaging, being able to provide image resolutions much higher than the micro-sized {alpha}-Al{sub 2}O{sub 3}:C, in view of their improved resolution provided by nano-particulates. (author)

TL and OSL studies on lithium borate single crystals doped with Cu and Ag

International Nuclear Information System (INIS)

Rawat, N.S.; Kulkarni, M.S.; Tyagi, M.; Ratna, P.; Mishra, D.R.; Singh, S.G.; Tiwari, B.; Soni, A.; Gadkari, S.C.; Gupta, S.K.

2012-01-01

Lithium borate (LBO) single crystals doped with Cu and Ag (0.25 mol% each) (Li 2 B 4 O 7 :Cu,Ag) are grown by the Czochralski method. The thermoluminescence readout on Li 2 B 4 O 7 :Cu,Ag crystals showed three glow peaks at∼375, 441 and 516 K for the heating rate of 1 K/s. The thermoluminescence sensitivity of the grown Li 2 B 4 O 7 :Cu,Ag single crystals is found to be 5 times TLD-100 and a linear dose response in the range 1 mGy to 1 kGy. The glow curve deconvolution reveals nearly first order kinetics for all the three peaks with trap depths 0.77, 1.25 and 1.34 eV respectively and corresponding frequency factors 1.6×10 9 , 1.3×10 13 and 6.8×10 11 s −1 . The continuous wave optically stimulated luminescence (CW-OSL) measurements were performed on the LBO:Cu,Ag single crystals using blue light stimulation. The traps responsible for the three thermoluminescence peaks in Li 2 B 4 O 7 :Cu,Ag are found to be OSL sensitive. The qualitative correlation between TL peaks and CW-OSL response is established. The photoluminescence studies show that in case of co-doping of Ag in LBO:Cu the emission at 370 nm in Cu states dominates over the transitions in Ag states implying doping of Ag plays a role as sensitizer when co-doped with Cu and increases overall emission. - Highlights: ► Growth of crack free single crystals of Li2B4O7 :Cu and Ag. ► Study of TL and OSL parameters for Li2B4O7 :Cu and Ag. ► Correlation of OSL with TL peaks. ► Optimization of OSL readout time with respect to residual TL.

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.

Personal exposure control using TLD

International Nuclear Information System (INIS)

Ishiguro, Hideharu; Takeda, Shinso

1979-01-01

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

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.)

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

Recent developments of optically stimulated luminescence materials and techniques for radiation dosimetry and clinical applications

Directory of Open Access Journals (Sweden)

Pradhan A

2008-01-01

Full Text Available During the last 10 years, optically stimulated luminescence (OSL has emerged as a formidable competitor not only to thermoluminescence dosimetry (TLD but also to several other dosimetry systems. Though a large number of materials have been synthesized and studied for OSL, Al 2 O 3 :C continues to dominate the dosimetric applications. Re-investigations of OSL in BeOindicate that this material might provide an alternative to Al 2 O 3 :C. Study of OSL of electronic components of mobile phones and ID cards appears to have opened up a feasibility of dosimetry and dose reconstruction using the electronic components of gadgets of everyday use in the events of unforeseen situations of radiological accidents, including the event of a dirty bomb by terrorist groups. Among the newly reported materials, a very recent development of NaMgF 3 :Eu 2+ appears fascinating because of its high OSL sensitivity and tolerable tissue equivalence. In clinical dosimetry, an OSL as a passive dosimeter could do all that TLD can do, much faster with a better or at least the same efficiency; and in addition, it provides a possibility of repeated readout unlike TLD, in which all the dose information is lost in a single readout. Of late, OSL has also emerged as a practical real-time dosimeter for in vivo measurements in radiation therapy (for both external beams and brachytherapy and in various diagnostic radiological examinations including mammography and CT dosimetry. For in vivo measurements, a probe of Al 2 O 3 :C of size of a fraction of a millimeter provides the information on both the dose rate and the total dose from the readout of radioluminescence and OSL signals respectively, from the same probe. The availability of OSL dosimeters in various sizes and shapes and their performance characteristics as compared to established dosimeters such as plastic scintillation dosimeters, diode detectors, MOSFET detectors, radiochromic films, etc., shows that OSL may soon become

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)

Natural and laboratory TT-OSL dose response curves: Testing the lifetime of the TT-OSL signal in nature

International Nuclear Information System (INIS)

Chapot, M.S.; Roberts, H.M.; Duller, G.A.T.; Lai, Z.P.

2016-01-01

This study compares natural and laboratory generated thermally transferred optically stimulated luminescence (TT-OSL) dose response curves (DRCs) for fine-grain quartz extracts from the Luochuan loess section in central China. Both DRCs saturate at high doses relative to the quartz OSL signal; the natural TT-OSL DRC saturates at about 2200 Gy and laboratory DRCs saturate at about 2700 Gy. However, the natural and laboratory TT-OSL DRCs deviate from one another at circa 150 Gy resulting in TT-OSL equivalent dose underestimation relative to palaeodoses expected from dose rates and independent age control. The lifetime of the TT-OSL signal at 10 °C, calculated from values of trap parameters E and s, is compared against the value for lifetime of the TT-OSL signal in nature at average burial temperature as determined from the age underestimation caused by deviation of the natural and laboratory generated DRCs. These two independent assessments of TT-OSL signal lifetime at Luochuan give similar values, suggesting that laboratory measurements of thermal stability reflect natural burial lifetimes and can potentially be used to correct TT-OSL ages for the difference between natural and laboratory dose response curves. - Highlights: • Natural and laboratory TT-OSL DRCs deviate at ∼150 Gy but saturate at higher doses. • TT-OSL signal lifetime at 10 °C calculated from measured E and s values is ∼180 ka. • TT-OSL signal lifetime at Luochuan estimated from the DRCs' deviation is ∼175 ka. • Natural and laboratory TT-OSL DRC deviation may be caused by low thermal stability. • Laboratory measurements of signal lifetime may be able to correct old TT-OSL ages.

A simple transformation for converting CW-OSL curves to LM-OSL curves

DEFF Research Database (Denmark)

Bulur, E.

2000-01-01

A simple mathematical transformation is introduced to convert from OSL decay curves obtained in the conventional way to those obtained using a linear modulation technique based on a linear increase of the stimulation light intensity during OSL measurement. The validity of the transformation...... was tested by the IR-stimulated luminescence curves from feldspars, recorded using both the conventional and the linear modulation techniques. The transformation was further applied to green-light-stimulated OSL from K and Na feldspars. (C) 2000 Elsevier Science Ltd. All rights reserved....

Emergency OSL dosimetry with commonplace materials

International Nuclear Information System (INIS)

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

2014-01-01

Several commonplace materials were studied as possible emergency optically stimulated luminescence (OSL) dosimeters. The materials included: paper currency (banknotes) and coins of different denomination and from different countries; plastic cards of different types (credit and debit cards, driver's license cards, membership cards, etc.), parts and details of clothing and shoes as well as samples of different fabrics. The samples displayed significant variability in their OSL properties. They differed in the intensity of the initial ‘native’ signal; the bleaching time of the OSL signal; the sensitivity to light of different wavelengths; the fading rate of OSL signals, etc. Procedures of OSL analysis were proposed to account for this variety. Values of the minimum measurable dose (MMD) were below 2 Gy for most tested samples if OSL measurements were conducted within one week of exposure and the samples were kept in dark since exposure (except samples of shoes that were kept under environmental light). The OSL signals in banknotes appear to originate from compounds containing aluminum, silicon, calcium and titanium – these elements were detected using X-ray microanalysis. For coins, the source of the OSL signals is speculated to be small particles of quartz, which were detected on the coins' surfaces. The X-ray microanalysis spectra from fabrics and shoes revealed sodium, aluminum, titanium, iron and nickel as elements that appeared to be responsible for the radiation sensitivity of those samples. It was concluded that, under certain constrained circumstances, paper and metallic money, personal plastic cards, clothing and shoes could be used as emergency OSL dosimeters in triage applications. - Highlights: • Money, plastic cards, clothing and shoes were studied as emergency OSL dosimeters. • Values of the minimum measurable doses were below 2 Gy for most tested samples. • Tested materials could be used as emergency OSL dosimeters in triage applications

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)

Development of an Equipment for Measuring OSL

International Nuclear Information System (INIS)

Chung, Ki Soo; Choe, Hong Soo

2010-05-01

A measurement system optically simulated luminescence (OSL) and thermoluminescence (TL) is developed. The system is composed by stimulation light part assembled by 3 ea of high brightness blue LEDs, temperature control system which can be controlled from room temperature to 300 .deg. C and filter package for separation of OSL and stimulation light with GG-420 and U-340 optical filters. The system was tested using Al 2 O 3 C OSL samples and a typical OSL curves were obtained. In addition, several OSL curves from LiAlO 2 C (a candidate of new OSLD material) were obtained and analyzed. A new algorithm for analysis of OSL curve and software (TOLAnal, Windows based) is developed and tested

A primary assessment of a daybreak 2200 OSL reader using fine grain quartz and CaSO4:Tm TLD

International Nuclear Information System (INIS)

Zhang Keqi; Chen Jie; Lu Yanchou; Wang Changsheng; Yang Chuancheng

2007-01-01

Daybreak 2200 OSL readers are widely used for luminescence dating applications. As the sample irradiation and illumination may affect discs in adjacent positions, it is critical to confirm that these factors do not introduce significant systematic errors. Effects of cross-irradiation and cross-bleaching were examined and quantified using fine-grain quartz and highly sensitive CaSO 4 :Tm dosimeters, and the irradiation offset time was measured. The cross-bleaching effect on adjacent aliquots is non-linear with no more than 15% OSL signal reduction following 10ks illumination with the power of blue LED being at 95% maximum. But at positions other than the nearest neighboring sample, almost no effect of cross-bleaching was found. The cross-talk dose, even to the nearest samples, was about 0.02% of the applied dose, and it decreased with increasing distance from the source. Offset time of the built-in Beta source shutter is 0.22 s, which can be neglected in regular dating, and leak dose of the source can be ignored as well. Finally, measurement consistency at Position 0.5, 10, ..... and 55 of the sample tray is better than 3% in relative standard deviation. (authors)

Enhancing and quenching luminescence with gold nanoparticle films: the influence of substrate on the luminescent properties

International Nuclear Information System (INIS)

Guidelli, Eder José; Baffa, Oswaldo; Ramos, Ana Paula

2016-01-01

Gold nanoparticle (AuNP) films were sputtered over glass and aluminum substrates to enhance optically stimulated luminescence (OSL), a luminescent technique employed for radiation detection, from x-ray irradiated NaCl nanocrystals. The AuNP films deposited over glass led to enhanced-OSL emission, whereas the AuNP films deposited on aluminum substrates quenched the OSL emission. The enhanced-OSL intensity is proportional to the optical density of the film's plasmon resonance band at the stimulation wavelength. For the case of the AuNP/aluminum films, the luminescence quenching diminishes, and OSL intensity partially recovers upon increasing the distance between the AuNPs and the aluminum substrates, and between the luminescent nanocrystals and the AuNP films. These results suggest that plasmonic interactions between the emitter nanocrystals, the localized surface plasmons (LSP) of the AuNPs, and the substrate are responsible for the OSL enhancement and quenching. In this sense, the substrate dictates whether LSP relaxation occurs by radiative or non-radiative transisitions, leading to enhanced or quenched OSL, respectively. Therefore, besides showing that AuNP films can enhance and/or tune the sensitivity of luminescent radiation detectors, and demonstrating OSL as a new technique to investigate mechanisms of plasmon-enhanced luminescence, these results bring insights on how substrates strongly modify the optical properties of AuNP films. (paper)

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.)

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)

Remote system for measurement of radon alpha emitter for population safety guards

International Nuclear Information System (INIS)

Jesus, Vasquez; Sajo-Bohus, Laszlo; Palacios, Daniel; Barros, Haydn

2013-01-01

The objective of this research project is to study the OSL properties for high doses of dosemeters traditionally applied in thermoluminescent dosimetry (TL), as CaF2: Dy (TLD 200) and CaF2: Mn (TLD 400), and thus verify the applicability of OSL technique in high-dose dosimetry

Remote system for measurement of radon alpha emitter for population safety guards; Sistema remoto de medicion de radon alfa emisor para la salvaguarda poblacional-3599

Energy Technology Data Exchange (ETDEWEB)

Jesus, Vasquez, E-mail: jesus.vasguez@lnl.infn.it [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Laboratorio Nazionale di Legnaro; Sajo-Bohus, Laszlo; Palacios, Daniel; Barros, Haydn, E-mail: sajobohus@gmail.com, E-mail: sanjuro.perdomo@gmail.com, E-mail: lab.nuclear@gmail.com [Universidad Simon Bolivar (USB), Caracas (Venezuela, Bolivarian Republic of). Laboratorio de Fisica Nuclear

2013-07-01

The objective of this research project is to study the OSL properties for high doses of dosemeters traditionally applied in thermoluminescent dosimetry (TL), as CaF2: Dy (TLD 200) and CaF2: Mn (TLD 400), and thus verify the applicability of OSL technique in high-dose dosimetry.

Component resolved bleaching study in natural calcium fluoride using CW-OSL, LM-OSL and residual TL glow curves after bleaching

International Nuclear Information System (INIS)

Angeli, Vasiliki; Polymeris, George S.; Sfampa, Ioanna K.; Tsirliganis, Nestor C.; Kitis, George

2017-01-01

Natural calcium fluoride has been commonly used as thermoluminescence (TL) dosimeter due to its high luminescence intensity. The aim of this work includes attempting a correlation between specific TL glow curves after bleaching and components of linearly modulated optically stimulated luminescence (LM-OSL) as well as continuous wave OSL (CW-OSL). A component resolved analysis was applied to both integrated intensity of the RTL glow curves and all OSL decay curves, by using a Computerized Glow-Curve De-convolution (CGCD) procedure. All CW-OSL and LM-OSL components are correlated to the decay components of the integrated RTL signal, apart from two RTL components which cannot be directly correlated with either LM-OSL or CW-OSL component. The unique, stringent criterion for this correlation deals with the value of the decay constant λ of each bleaching component. There is only one, unique bleaching component present in all three luminescence entities which were the subject of the present study, indicating that each TL trap yields at least three different bleaching components; different TL traps can indicate bleaching components with similar values. According to the data of the present work each RTL bleaching component receives electrons from at least two peaks. The results of the present study strongly suggest that the traps that contribute to TL and OSL are the same. - Highlights: • A component resolved bleaching study was attempted to CaF_2:N in terms of CW-OSL, LM-OSL and RTL. • Bleaching decay constants originating from different TL peaks yield overlapping values. • Three to five individual components were used in order to describe the bleaching behavior in all luminescence entities. • There is only one, unique bleaching component present in all three luminescence entities.

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)

Influence of thermal treatment on OSL regeneration in potassium chloride

International Nuclear Information System (INIS)

Majgier, Renata; Biernacka, Magdalena; Mandowski, Arkadiusz

2016-01-01

Optically stimulated luminescence (OSL) of pure analytical potassium chloride (KCl) prepared in two different forms (crystals and pellets) was studied. The occurrence of regeneration effect (self-renewal of the OSL signal) in the material was examined. The experiments using the variable delay OSL (VD-OSL) method were carried out. Performed measurements allowed to determine time scale of the phenomenon, as well as quantitative changes of regeneration depending on thermal treatment before and after irradiation. Significant increase of the OSL regeneration was noticeable for pellets after the application of the annealing before irradiation, while for crystals a substantial decrease of regeneration was observed. Preheating applied after irradiation caused that self-renewal of OSL signal was drastically reduced or completely suppressed depending on the form of KCl samples. - Highlights: • Optically stimulated luminescence (OSL) of potassium chloride (KCl) was studied. • The measurements were performed using the variable delay OSL method (VD-OSL). • It was found that regeneration of OSL intensity in KCl could be as high as 2000%. • Annealing caused reduction of OSL renewal for crystals and its increase for pellets. • Preheating after irradiation removed or significantly reduced the OSL regeneration.

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

International Nuclear Information System (INIS)

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

2002-01-01

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

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

International Nuclear Information System (INIS)

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

2010-01-01

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

Utilisation of OSL from table salt in retrospective dosimetry

International Nuclear Information System (INIS)

Fujita, Hiroki; Jain, Mayank; Murray, Andrew S.

2011-01-01

Common salt (NaCl) has previously been suggested for use in dose estimation in accident dosimetry. In this study, we investigated the optically stimulated luminescence (OSL) and violet thermoluminescence (VTL) characteristics of 'Aji-Shio' (Ajinomoto), a Japanese commercial salt. A comparison of OSL and TL signals allowed identification of common source traps. The initial OSL signal contained a dominant thermally unstable component, which necessitated prior heat treatment. Based on these luminescence characteristics, a single-aliquot regenerative-dose (SAR) OSL protocol was modified and tested. The protocol worked very well for six types of salt, but not for four other types of salt. A minimum detection limit of ∼15 mGy was estimated using the OSL protocol; this is lower than the value obtained from other forms of OSL retrospective dosimetry and lower than that obtained using electron spin resonance (ESR) dosimetry. It was concluded that the OSL from Japanese commercial salt could be used successfully to derive precise estimates of accident dose. (author)

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

International Nuclear Information System (INIS)

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

1987-03-01

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

A study on the development of personal radiation dosimetry system based on the pulsed optically stimulated luminescence of α-Al2O3:C

International Nuclear Information System (INIS)

Lee, Sang Yoon

2000-02-01

High quality radiation dosimetry is for workers who rely upon personal dosimeters to record the amount of radiation to which they are exposed. Radiation physicists have been exploring thermoluminescence dosimeter (TLD) for personal monitoring since the mid 1960s, although, widespread use has only occurred in the last 20 years as automated analytical systems and high quality TLD crystals became commercially available. nowadays, multiple TLD (thermoluminescence dosimeter) chips with appropriate physical filters are generally used for measurements of the personal dose equivalent quantities, H p (d). Though the TLD offers several advantages not possessed by radiological film, it does not offer the some type of advantages as films: re-analysis of an exposure situation is prohibited because the analysis process clears all of the useful dosimetric traps and a record of the luminescence intensity in the form of a glow curve is all that is available after analysis. In addition, the high heating temperatures restrict packaging methods and prevent competitively priced thin films of TLD crystal powders. Optically stimulated luminescence (OSL) technology avoids many engineering limitations imposed by the high heating temperatures used for TLD technology. OSL crystalline powders can be dispersed in various plastics unable to withstand the TLD heating regimen. With uniform dispersion in the plastic, mass-manufacturing techniques can produce large quantities of identically performing detectors. The first proposal conducted by Markey et al. for applications and potentials of α-AI 2 O 3 :C for OSL dosimetry opened a new era for this phosphor. Pulsed and continuous wave OSL studies carried out on α-AI 2 O 3 :C have shown that the material seems to be the most promising for routine application of OSL for dosimetric purposes. The main objective of this study is to develop a multi-area personal OSL dosimetry system using α-AI 2 O 3 :C by taking advantage of its optical properties and

OSL at elevated temperatures: Towards the simultaneous thermal and optical stimulation

International Nuclear Information System (INIS)

Polymeris, George S.

2015-01-01

In routine OSL dating measurements, a preheat procedure at high temperatures is used to empty the shallow traps. Thus no contribution from shallow traps was expected as each OSL measurement is subsequently performed at moderately high temperatures, around 110–125 °C. The present work attempts to consider the OSL measurements performed at elevated temperatures without any previous preheat as a case of simultaneous thermal and optical stimulation of the same trap. Towards this direction, a set of proposed equations is derived for all three different cases of optical stimulation modes, namely CW-OSL, LM-OSL as well as PS-LM-OSL. According to these equations, indicative features of thermally activated OSL processes are expected, such as the steepening of CW-OSL decay curves as either stimulation temperature or intensity increases, as well as the shifting of the stimulation time of the maximum intensity for both LM-OSL and PS-LM-OSL curves towards shorter times with increasing temperatures. Experimentally, specific measurement sequences after varying stimulation temperature and/or intensity were applied in order to estimate the values of associated trap parameters, such as activation energy and photo-ionization cross-section. Experimental OSL data from a milky natural quartz sample stand in good agreement of these theoretical considerations in the case of 110 °C TL peak and the intense OSL component C 2 monitored at RT. - Highlights: • OSL at elevated temperatures without preheat results from two simultaneous stimulation modes. • Equations were derived assuming of linear superposition of two stimulation modes. • Data for 110 °C TL peak and OSL C 2 at RT stand in agreement with these equations. • Results verify the linear superposition of the two stimulation modes

BeOSL system for personal dosimetry : dosimetric characteristics and practical application; Sistema BeOSL para dosimetria personal : caracteristicas dosimetricas y la aplicacion practica

Energy Technology Data Exchange (ETDEWEB)

Mende, E. [Helmholtz Zentrum Munchen, German Research Center for Environmental Health, Working Group Engineering, D-85764 Neuherberg (Germany)

2015-10-15

Full text: BeOSL system of Dosimetric s is very easy to use, assimilate and maintain. Our dosimeter defines a milestone in the supervision of personal equivalent dose of Hp (10) and Hp (0.07) it covers the range of total energy of 16 KeV to 10 MeV. For this energy range is exceptional in its energy dependence for official personal dosimetry. The BeOSL system consists of two modules, one of them is the BeOSL reader that measures the radiation exposure using the latest technology, optically stimulated luminescence (OSL). The reading is extremely fast; it does not require consumables such as nitrogen or other. The detector material is beryllium oxide (Be O); this is an OSL material tissue equivalent and therefore is ideal for personal dosimetry. The BeOSL technology allows multiple readings of the dosimeter (re-read) to verify the dose or archive the dosimeter. One of the biggest advantages of BeOSL system is its modular concept allows the system to run as a manual solution or as a complete automated robotic system, which can be filled with up to 5,000 dosimeters as bulk cargo. (Author)

The TL and OSL study of hydroxyapatites for dosimetric applications

International Nuclear Information System (INIS)

Alencar, Marcus A. Vallim de

2009-01-01

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

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

Introduction of a new dosimetry system based on optically stimulated luminescence (OSL) in our personal monitoring service

International Nuclear Information System (INIS)

Hubner, S.

2014-08-01

The personal monitoring service named Auswertungsstelle is part of the Helmholtz Zentrum Munchen, a non-profit-making research center in Germany. As one of the four monitoring services in Germany, we have been a reliable partner in radiation protection for more than 60 years. With about 1.9 million dose assessments per year, we are the largest monitoring service in Europe. For dozens of years, our main dosimeter used in whole-body dosimetry has been a film dosimeter. Although its dosimetric properties are still up to date, film dosimetry won.t be a sustainable technique for the use in monitoring services. Therefore, a project with the objective of investigating alternative dosimetric materials and methods was launched in the late 1990 at the Helmholtz Zentrum Munchen. Based on this research work, the use of Be O as an OSL dosimeter was studied by the radiation physics group of the Tu Dresden, by order and on account of the Auswertungsstelle at the Helmholtz Zentrum Munchen. It was shown, that ceramic Be O features promising dosimetric properties, making Be O detectors particularly suitable for being used in all applications in whole-body dosimetry measuring photons. Ceramic Be O material has an excellent resistance to environmental influences. The Be O chips are almost tissue equivalent. Therefore, these detectors show low photon energy dependence. A new personal dosimetry system based on the OSL dosimetry of Be O was developed. Applying this system, the Auswertungsstelle offers OSL-dosimeters for official monitoring of the Personal Dose Equivalent Hp(10) since 2011. This OSL-System is accredited according to DIN IEC 62387 and we obtained the corresponding type approval by the Ptb, the national metrology institute in Germany. Sophisticated logistics was developed and installed. High degree of automation was achieved by robots for dosimeter assembly and machines for packing, labelling and unpacking of the dosimeters. To become a sustainable dosimetry system not only

Introduction of a new dosimetry system based on optically stimulated luminescence (OSL) in our personal monitoring service

Energy Technology Data Exchange (ETDEWEB)

Hubner, S., E-mail: stephan.huebner@helmholtz-muenchen.de [Helmholtz Zentrum Munchen, German Research Center for Environmental Health, D-80219, Munich (Georgia)

2014-08-15

The personal monitoring service named Auswertungsstelle is part of the Helmholtz Zentrum Munchen, a non-profit-making research center in Germany. As one of the four monitoring services in Germany, we have been a reliable partner in radiation protection for more than 60 years. With about 1.9 million dose assessments per year, we are the largest monitoring service in Europe. For dozens of years, our main dosimeter used in whole-body dosimetry has been a film dosimeter. Although its dosimetric properties are still up to date, film dosimetry won.t be a sustainable technique for the use in monitoring services. Therefore, a project with the objective of investigating alternative dosimetric materials and methods was launched in the late 1990 at the Helmholtz Zentrum Munchen. Based on this research work, the use of Be O as an OSL dosimeter was studied by the radiation physics group of the Tu Dresden, by order and on account of the Auswertungsstelle at the Helmholtz Zentrum Munchen. It was shown, that ceramic Be O features promising dosimetric properties, making Be O detectors particularly suitable for being used in all applications in whole-body dosimetry measuring photons. Ceramic Be O material has an excellent resistance to environmental influences. The Be O chips are almost tissue equivalent. Therefore, these detectors show low photon energy dependence. A new personal dosimetry system based on the OSL dosimetry of Be O was developed. Applying this system, the Auswertungsstelle offers OSL-dosimeters for official monitoring of the Personal Dose Equivalent Hp(10) since 2011. This OSL-System is accredited according to DIN IEC 62387 and we obtained the corresponding type approval by the Ptb, the national metrology institute in Germany. Sophisticated logistics was developed and installed. High degree of automation was achieved by robots for dosimeter assembly and machines for packing, labelling and unpacking of the dosimeters. To become a sustainable dosimetry system not only

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

International Nuclear Information System (INIS)

Bravim, Amanda

2015-01-01

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

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)

The origin of the medium OSL component in West Australian quartz

International Nuclear Information System (INIS)

Wang, X.L.; Du, J.H.; Adamiec, G.; Wintle, A.G.

2015-01-01

Optically stimulated luminescence (OSL) of a coarse-grained sedimentary quartz from West Australia was investigated. Observations of OSL and TL (thermoluminescence) were made following a series of experiments using different heating and optical bleaching conditions, and with optical stimulation at several different temperatures. Analysis of the fast and medium OSL components suggests that the medium OSL component observed after heating at 260 °C is a by-product of the production of the fast component, and both of them have as their original source the 325 °C TL trap. During fast OSL production following irradiation and preheating, some of the electrons evicted into the conduction band are re-trapped in an intermediate trap corresponding to the 170 °C TL peak; from here they are instantaneously stimulated to give rise to the medium OSL signal when the blue light stimulation is switched on, and subsequently result in the residual recuperated TL after the blue light is switched off. The kinetic properties of the medium OSL component are determined by the properties of both the 170 °C and 325 °C TL traps in contrast to the conventional interpretation of the medium component being derived from an independent source trap. Therefore, the 170 °C TL trap also plays unexpected roles in quartz OSL production with elevated stimulation temperatures (e.g. 125 °C or 130 °C, currently used for OSL dating), while the 110 °C TL trap and its influences are being avoided. - Highlights: • Quartz medium OSL component is a by-product of fast OSL component production. • Medium component is mediated by the 170 C TL peak. • Phototransfer is responsible for the medium OSL

More on the TR-OSL signal from BeO ceramics

International Nuclear Information System (INIS)

Bulur, Enver

2014-01-01

Time Resolved Optically Stimulated Luminescence (TR-OSL) from BeO ceramics was investigated using blue (445 nm) and near-IR light (852 nm) for stimulation. Stimulation spectrum of the TR-OSL signal – as measured in the interval 700 to 420 nm- was observed to increase monotonically with the decreasing stimulation wavelength. In addition to the “fast” and “slow” components observed with blue light stimulation, IR stimulated TR-OSL spectra of irradiated BeO ceramics were observed to have two components with average lifetimes around ∼2.5 μs and ∼17 μs. Emission spectra of the both IR stimulated TR-OSL components were observed to have a broad emission band peaking around 330 nm. Thermal stability of the IR stimulated TR-OSL signal was studied by making preheating experiments in the range from 100 °C to 190 °C. It was observed that the IR stimulated OSL signal is stable up to ∼150 °C and decay afterwards. Radiation dose response of the IR stimulated luminescence signal was obtained in the range from 5 to 500 Gy. Both blue and IR stimulated TR-OSL signals grew up to 100 Gy and exhibited saturation for higher doses. Additionally, measurement temperature dependence of the components was also investigated and for the ∼2 μs component thermal assistance with activation energy around 0.16 eV was observed. It seems that the fast component of the blue stimulated TR-OSL component can be correlated to the ∼2 μs IR stimulated TR-OSL component. - Highlights: • IR Stimulated Time-Resolved OSL from BeO was studied. • Two components with lifetimes ∼2 and ∼17us were observed. • IR stimulated TR-OSL signal is found to be stable up to 150 °C. • Thermal quenching energy of the 2us component was found as 0.16 eV

Remote TL and OSL for asteroid and meteorite study

International Nuclear Information System (INIS)

Takaki, Shunji; Ikeya, Motoji; Yamanaka, Chihiro

1997-01-01

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

BeOSL system for personal dosimetry : dosimetric characteristics and practical application

International Nuclear Information System (INIS)

Mende, E.

2015-10-01

Full text: BeOSL system of Dosimetric s is very easy to use, assimilate and maintain. Our dosimeter defines a milestone in the supervision of personal equivalent dose of Hp (10) and Hp (0.07) it covers the range of total energy of 16 KeV to 10 MeV. For this energy range is exceptional in its energy dependence for official personal dosimetry. The BeOSL system consists of two modules, one of them is the BeOSL reader that measures the radiation exposure using the latest technology, optically stimulated luminescence (OSL). The reading is extremely fast; it does not require consumables such as nitrogen or other. The detector material is beryllium oxide (Be O); this is an OSL material tissue equivalent and therefore is ideal for personal dosimetry. The BeOSL technology allows multiple readings of the dosimeter (re-read) to verify the dose or archive the dosimeter. One of the biggest advantages of BeOSL system is its modular concept allows the system to run as a manual solution or as a complete automated robotic system, which can be filled with up to 5,000 dosimeters as bulk cargo. (Author)

Application of pulsed OSL to polymineral fine-grained samples

International Nuclear Information System (INIS)

Feathers, James K.; Casson, M. Aksel; Schmidt, Amanda Henck; Chithambo, Makaiko L.

2012-01-01

Pulsed OSL is applied to nine fine-grained sediment samples from Sichuan province, China, using stimulating pulses of 10 μs on and 240 μs off, with an infrared exposure prior to each OSL measurement. Comparison of fading rates between pulsed and non-pulsed signals, the latter also obtained with a preceding IR exposure, shows that fading is significant for mainly the non-pulsed signals. Presence of a pulsed IRSL and the magnitudes of b-value to correct for lower alpha efficiency suggest that pulsing does not fully remove a significant feldspar signal, only a fading component. Comparison with ages of quartz extracts shows that pulsed OSL ages are consistent, while CW-OSL ages are slightly older and CW-IRSL ages are much older. The older ages suggest a less well-bleached feldspar component.

Performance of OSL dosimeters in clinical beams from mammography; Desempenho de dosimetros OSL em feixes clinicos empregados na mamografia

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Caio V.; Cabete, Henrique V.; Alves, Fatima F.R.; Pires, Silvio R.; Medeiros, Regina B.; Freitas, Marcelo B. [Universidade Federal de Sao Paulo (HSP/EPM/UNIFESP), SP (Brazil). Escola Paulista de Medicina; Malthez, Anna Luiza M.C. [Universidade Estadual de Campinas (CPG/FEEC/UNICAMP), Campinas, SP (Brazil). Faculdade de Engenharia Eletrica e de Computacao. Programa de Pos-Graduacao

2015-08-15

The search for the relationship between dose and mammography image is critical to the quality of clinical practice. In this sense, dosimetry using optically stimulated luminescent detectors (OSLD) is configured as alternative to traditional methods and allows on-site dose checks received by patients. This study aimed to verify the performance of OSL dosimeters in clinical beams typically used in mammography. For this, aluminum oxide detectors, especially designed to reduce interference on the image quality, were exposed to radiation beam combining targets and filters of a mammography equipment with digital imaging system. In addition were also employed lithium fluoride detectors irradiated under the same conditions, together with a ionization chamber for determination of dose values. A homogeneous acrylic phantom was designed and used for simulating different breast and also determine internal dose values under the irradiation conditions. The results allowed the determination of calibration factors (OSL signal x dose) of the exposed detectors to the radiation beams typically used in clinical practice. The phantom images and the comparison between TL and OSL responses suggest the possibility of routine use of the OSL dosimetry system in mammography. (author)

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.

Tl and OSL on diopside crystal

International Nuclear Information System (INIS)

Cano, N.F.; Watanabe, S.; Mittani, J.C.R.; Yukihara, E.G.

2006-01-01

The diopside with chemical composition CaMgSi 2 O 6 is part of an important solid solution series of the pyroxene group. The mineral is commonly found in meteorites and it is an important rock forming mineral of medium and high grade metamorphic rocks which are rich in calcium. In the bibliography it is possible to found several studies on electron spin resonance (ESR), reflectance, etc. but not on thermoluminescence (TL) or optically stimulated luminescence (OSL). In the present work we studied diopside TL and OSL behaviour on natural and natural irradiated samples. The sample used in our study is a white coloured diopside provided by Mineracao Sao Judas located in Sao Paulo, Brazil. The X-Ray Fluorescence technique has shown high concentrations of SiO 2 (55.81 % mol), CaO (23.47 % mol), MgO (18.03 % mol), Al 2 O 3 (1.56 % mol), Fe 2 O 3 (0.53 % mol), K 2 O (0.44 % mol), TiO 2 (0.065 % mol), P 2 O 5 (0.026 % mol), and MnO (0.013 % mol). TL measurements on natural samples show four TL peaks at 160, 260, 360, and 450 C. After beta-irradiation an increment mainly in the low temperature peaks is observed. As for OSL measurements, low OSL signal was observed on natural samples using blue light stimulation and UV detection. The intensity of the signal was observed to increase with the irradiation dose. (Author)

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

International Nuclear Information System (INIS)

Fiechtner, A.; Wernli, C.

2001-01-01

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

Developing a SAR TT-OSL protocol for volcanically-heated aeolian quartz from Datong (China)

DEFF Research Database (Denmark)

Liu, Jinfeng; Murray, Andrew S.; Jain, Mayank

2012-01-01

The thermally-transferred optically stimulated luminescence (TT-OSL) responses of chemically-purified fine-grained quartz from a lava-baked aeolian sediment from Datong (China) are presented. Our main focus is to examine the suitability of the test dose TT-OSL and OSL response to monitor sensitiv......The thermally-transferred optically stimulated luminescence (TT-OSL) responses of chemically-purified fine-grained quartz from a lava-baked aeolian sediment from Datong (China) are presented. Our main focus is to examine the suitability of the test dose TT-OSL and OSL response to monitor...

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)

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

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)

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)

Occupational radiation exposure in Slovakia

International Nuclear Information System (INIS)

Boehm, K.; Cabanekova, H.

2014-01-01

Recently are 2 nuclear power plants in operation in the Slovak republic. Apart from nuclear facilities there are 450 licensed undertakings with monitored workers. The majority of the licensed undertakings are active in health care. In Slovak republic are five dosimetry services performing assessments on personal doses due to external exposure and two dosimetry services are approved to carry out monitoring of internal exposure. Dosemeters used for the monitoring of external individual exposure include: personal whole-body film dosemeters, thermoluminescence dosemeters (TLD) or optically stimulated luminescence dosimeters (OSL) for measurements of beta and gamma radiation; TLD for measurements of neutron radiation and TLD for extremities. The measured operational dose quantities are Hp(10), Hp(3) and Hp(0.07). Approved dosimetry service reports the measured dose data to the employers and to the Central register of occupational doses (CROD). Annually are monitored about 12500 - 16200 active workers. Average effective doses per one monitored worker are presented. (author)

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)

Dosimetry in the multi kilo-Gray range using optically-stimulated luminescence (OSL) and thermally-transferred OSL from quartz

International Nuclear Information System (INIS)

Burbidge, C.I.; Cabo Verde, S.I.; Fernandes, A.C.; Prudencio, M.I.; Botelho, M.L.; Dias, M.I.; Cardoso, G.

2011-01-01

This study explores the potential for using photon-stimulated luminescence of quartz grains to retrospectively evaluate multi-kGy gamma radiation doses. Subsamples from two ceramic tiles were given 60 Co gamma doses of 1, 3, 5, 15 and 30 kGy (nominal), accompanied by PMMA dosimeters and quartz grains from a geological sample known to exhibit thermally-transferred optically-stimulated luminescence (TTOSL). Following gamma irradiation, quartz grains were prepared from each subsample. OSL and TTOSL signals were measured for different preheat temperatures, and following re-irradiation with beta doses designed to equal the nominal gamma doses. OSL responses to 10 Gy beta test doses were measured following each cycle of high dose irradiation. Gamma doses were predicted from the beta responses, to evaluate the effectiveness of retrospective dose evaluation for different signal integrals, preheat combinations, and dose intervals. The use of linear modulation limited maximum OSL signal levels to 1.5 x 10 6 cps without reducing detector sensitivity, for the measurement of smaller TTOSL signals. The dosimetric behaviour of the three samples differed significantly: the best results were obtained from the pre-prepared geological quartz. OSL signals evident at short stimulation times, which are conventionally used for dosimetry and dating, did not in general appear appropriate for dosimetry in the range of doses examined. They exhibited dose response characteristics that were highly preheat dependant and variable in form between samples, which contained rapidly saturating and/or non-monotonic components. Higher preheats, up to 300 o C, preferentially removed OSL and TTOSL signals evident at longer stimulation times: those that remained yielded growth in signal with dose to approximately 10 kGy, but the accuracy of retrospective dose determinations was variable. TTOSL signals evident at short stimulation times increased proportionally with dose when 300 o C preheats were used, up

Constraining the timing of palaeosol development in Iranian arid environments using OSL dating

DEFF Research Database (Denmark)

Rashidi, Zakieh; Sohbati, Reza; Karimi, Alireza

2018-01-01

are compared to investigate the degree of bleaching of quartz OSL in individual samples at the time of deposition. A comparison between the quartz OSL and K-feldspar IR50 ages shows that 12 out of 15 samples were probably well-bleached prior to deposition. The 17 OSL ages constrain at least four broad phases......The ages of palaeosols in arid environments in Iran are constrained using the optically stimulated luminescence (OSL) signal from quartz. The luminescence properties of quartz OSL and K-feldspar infrared stimulated luminescence (IRSL) at 50 °C (IR50) and post-IR IRSL at 290 °C (pIRIR290) signals...

Influence of pre-measurement thermal treatment on OSL of synthetic quartz measured at room temperature

International Nuclear Information System (INIS)

Kale, Y.D.; Gandhi, Y.H.

2008-01-01

Much effort has been made to study the influence of pre-measurement thermal treatment and ionizing radiation on quartz specimens owing to its use in a large number of applications. Optically stimulated luminescence (OSL) being a structured and sensitive phenomenon promises to correlate the responsible color center and luminescence emission. OSL studies on quartz with such conditions can reveal many significant results. The aim of the present investigation is to understand the effect of annealing temperature on OSL characteristics of synthetic quartz recorded at room temperature. At identical annealing duration and β-dose, the shape of OSL decay curve remains non-exponential; when specimens annealed at lower temperature (∼400 deg. C). The shape of decay curve changes to exponential in nature along with rise in OSL intensity when the specimen was given higher temperature of annealing (>400 deg. C). The effects of such protocol on pattern of OSL sensitivity as well as area under the OSL decay curve are also presented here. The presence of shallow traps, when OSL decay curve was recorded at room temperature seems to be responsible for the changes in OSL pattern. The influence of shallow traps is attributed to non-exponential decay of OSL recorded at room temperature

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)

Application of the Sunna dosimeter film in gamma and electron beam radiation processing

DEFF Research Database (Denmark)

Kovács, A.; Baranyai, M.; Wojnárovits, L.

2000-01-01

The OSL (optically stimulated luminescence) based Sunna film containing a microcrystalline dispersion of LIF in a polymer matrix has been recently introduced for high-dose dosimetry. Our previous investigations revealed the applicability of the system in the dose range of 0.01-100 kGy, but irradi...... significant in the case of OSL analysis for doses above 5 kGy. The applicability of two types of Sunna films in electron and gamma radiation processing is discussed in the paper. (C) 2000 Elsevier Science Ltd. All rights reserved.......The OSL (optically stimulated luminescence) based Sunna film containing a microcrystalline dispersion of LIF in a polymer matrix has been recently introduced for high-dose dosimetry. Our previous investigations revealed the applicability of the system in the dose range of 0.01-100 k......Gy, but irradiation temperature and dose rate effects above 5 kGy reduced its usefulness. The recent discovery of the use of spectrophotometric analysis in the UV range for measuring doses above 5 kGy is a suitable option, while the OSL analysis can be applied for measuring lower doses due to the lack of temperature...

The new IRSN passive dosemeter using the RPL technique

International Nuclear Information System (INIS)

Fraboulet, P.; Cale, E.; Itie, C.; Bottollier-Depois, Jean-Francois

2008-01-01

Full text: The Institute for Radiological Protection and Nuclear Safety (IRSN) is the French public organisation in charge of research and expertise into nuclear safety and radiation protection. IRSN provides also services in these areas like dosimetric survey for 150,000 workers liable to be exposed to ionising radiation. At present whole-body dosemeters provided by the IRSN laboratory for photons and beta-particles are based on photographic films. In order to anticipate likely supplying decrease and to improve the service, IRSN has decided to replace photographic films by dosemeters based on the radio-photoluminescence (RPL) technology, supplied by the Japanese Company Chiyoda Technol. RPL was chosen after a thorough comparison with other available passive techniques (thermoluminescent dosemeters: TLD, and optically stimulated luminescence: OSL). Constraints due to large-scale production of dosemeters (packaging, shipping, etc.) were taken into account as well. Irradiation tests for five different dosemeters, based on the 3 available techniques (TLD, OSL, RPL) were performed. The main results of these tests are presented (energy, dose and angular response, detection threshold, etc.) together with main technical characteristics of the new RPL dosemeter (range in energy and dose, homogeneity, reproducibility, re-reading, information about radiation type from reading, etc.). This dosemeter is expected to give significative improvements in the IRSN laboratory's provision of service thanks to better dosimetric performances and because it offers the possibility to get information to analyse over-exposure circumstances. (author)

Desiccants for retrospective dosimetry using optically stimulated luminescence (OSL)

International Nuclear Information System (INIS)

Geber-Bergstrand, Therése; Bernhardsson, Christian; Christiansson, Maria; Mattsson, Sören; Rääf, Christopher L.

2015-01-01

Optically stimulated luminescence (OSL) was used to test different kinds of desiccants for their potential use in retrospective dosimetry. Desiccants are used for the purpose of absorbing liquids and can be found in a number of items which may be found in the immediate environment of a person, including hand bags, drug packages, and the vehicles of rescue service teams. Any material exhibiting OSL properties suitable for retrospective dosimetry is a useful addition to the existing dosimetry system available in emergency preparedness. Eleven kinds of desiccants were investigated in order to obtain an overview of the fundamental OSL properties necessary for retrospective dosimetry. Measurements were made using a Risø TL/OSL reader and irradiations were achieved with the 90 Sr/ 90 Y source incorporated in the reader. Several of the desiccants exhibited promising properties as retrospective dosemeters. Some of the materials exhibited a strong as-received signal, i.e. without any laboratory irradiation, but the origin of this signal has not yet been established. The minimum detectable dose ranged from 8 to 450 mGy for ten of the materials and for one material (consisting of natural clay) the minimum detectable dose was 1.8 Gy. - Highlights: • Desiccants can be used as fortuitous dosemeters using OSL. • The minimum detectable dose for processed desiccants range from 8 to 450 mGy. • The minimum detectable dose for natural clay was 1.8 Gy

Using OSL dating to quantify rates of Earth surface processes

Science.gov (United States)

Rhodes, E. J.; Rittenour, T. M.

2010-12-01

In Optically Stimulated Luminescence (OSL), the dating signal is reset when mineral grains are exposed to light or heat, and gradually rebuilds during subsequent burial by interaction with ionising radiation. Quartz and feldspar provide useful OSL signals demonstrating rapid signal reduction in only seconds of light exposure. Age estimates ranging from under 1 year to around 200,000 years can be determined for a wide range of sedimentary contexts, including dunes, marine deposits, fluvial and glacial environments, and recent developments provide the framework for low temperature thermochronometric applications on timescales comparable with rapid climate fluctuations. In this presentation, we explore the range of applications for determining rates of Earth surface processes using OSL. We examine technical limitations, and provide a framework for overcoming current difficulties experienced in several specific regions and contexts. We will focus on OSL dating applications to glacigenic and fluvial records, along with use of the technique in tectonic and paleoseismic contexts. In many ways, these represent the most challenging environments for OSL; rapid high energy deposition is associated with incomplete signal zeroing, and the characteristics of quartz in many of these environments make it difficult to derive precise age estimates using this mineral. We will introduce innovative methods to overcome these limitations, both existing and those under development.

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.

Optically stimulated luminescence (OSL) of dental enamel for retrospective assessment of radiation exposure

International Nuclear Information System (INIS)

Yukihara, E.G.; Mittani, J.; McKeever, S.W.S.; Simon, S.L.

2007-01-01

This paper briefly reviews the optically stimulated luminescence (OSL) properties of dental enamel and discusses the potential and challenges of OSL for filling the technology gap in biodosimetry required for medical triage following a radiological/nuclear accident or terrorist event. The OSL technique uses light to stimulate a radiation-induced luminescence signal from materials previously exposed to ionizing radiation. This luminescence originates from radiation-induced defects in insulating crystals and is proportional to the absorbed dose of ionizing radiation. In our research conducted to date, we focused on fundamental investigations of the OSL properties of dental enamel using extracted teeth and tabletop OSL readers. The objective was to obtain information to support the development of the necessary instrumentation for retrospective dosimetry using dental enamel in laboratory, or for in situ and non-invasive accident dosimetry using dental enamel in emergency triage. An OSL signal from human dental enamel was detected using blue, green, or IR stimulation. Blue/green stimulation associated with UV emission detection seems to be the most appropriate combination in the sense that there is no signal from un-irradiated samples and the shape of the OSL decay is clear. Improvements in the minimum detection level were achieved by incorporating an ellipsoidal mirror in the OSL system to maximize light collection. Other possibilities to improve the sensitivity and research steps necessary to establish the feasibility of the technique for retrospective assessment of radiation exposure are also discussed

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

International Nuclear Information System (INIS)

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

2016-01-01

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

Natural and laboratory OSL growth curve–Verification of the basic assumption of luminescence dating

International Nuclear Information System (INIS)

Kijek, N.; Chruścińska, A.

2016-01-01

The basic assumption of luminescence dating is the equality between the growth curve of OSL generated by the natural radiation and the OSL growth curve reconstructed in laboratory conditions. The dose rates that generate the OSL in nature and in laboratory experiments differ by about ten orders of magnitude. Recently some discrepancies between the natural and laboratory growth curves have been observed. It is important to establish their reasons in order to introduce appropriate correction into the OSL dating protocol or to find a test that allows to eliminate the samples which should not be used for dating. For this purpose, both growth curves, natural and laboratory, were reconstructed by means of computer simulations of the processes occurring in the sample during its deposition time in environment as well as those which occur in a laboratory during dating procedure. The simulations were carried out for three models including one shallow trap, two OSL traps, one disconnected deep and one luminescence center. The OSL model for quartz can be more complex than the one used in the presented simulations, but in spite of that the results show effects of growth curves discrepancies similar to those observed in experiments. It is clear that the consistency of growth curves is not a general feature of the OSL processes, but rather a result of an advantageous configuration of trap parameters. The deep disconnected traps play the key role and their complete filling before the zeroing of OSL signal is a necessary condition of the growth curves' consistency. - Highlights: • Process of OSL growth curve generation in nature and in laboratory was simulated. • Discrepancies between the natural and the laboratory growth curves are observed. • Deep disconnected traps play the key role in growth curve inequality. • Empty deep traps before zeroing of OSL cause the inequality of growth curves.

Emergency EPR and OSL dosimetry with table vitamins and minerals.

Science.gov (United States)

Sholom, S; McKeever, S W S

2016-12-01

Several table vitamins, minerals and L-lysine amino acid have been preliminarily tested as potential emergency dosemeters using electron paramagnetic resonance (EPR) and optically stimulated luminescence (OSL) techniques. Radiation-induced EPR signals were detected in samples of vitamin B2 and L-lysine while samples of multivitamins of different brands as well as mineral Mg demonstrated prominent OSL signals after exposure to ionizing radiation doses. Basic dosimetric properties of the radiation-sensitive substances were studied, namely dose response, fading of the EPR or OSL signals and values of minimum measurable doses (MMDs). For EPR-sensitive samples, the EPR signal is converted into units of dose using a linear dose response and correcting for fading using the measured fading dependence. For OSL-sensitive materials, a multi-aliquot, enhanced-temperature protocol was developed to avoid the problem of sample sensitization and to minimize the influence of signal fading. The sample dose in this case is also evaluated using the dose response and fading curves. MMDs of the EPR-sensitive samples were below 2 Gy while those of the OSL-sensitive materials were below 500 mGy as long as the samples are analyzed within 1 week after exposure. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Modelling the thermal bleaching of OSL signal in the case of a competition between recombination centres

International Nuclear Information System (INIS)

Chruscinska, A.

2009-01-01

The thermal bleaching of the optically stimulated luminescence (OSL) has been investigated by computer simulations for a model including three traps and two luminescence centres. The deepest trap is active only during the OSL process. Two other traps are active only during the thermal bleaching. The thermal bleaching effects on the OSL intensity as well as on the OSL curve shape are presented for the wide range of trap and luminescence centre parameters and for the different settings of optical detection window. The conventional OSL curve analysis consisting in decomposition of the OSL curve into first order components is applied to the simulation results and the optical cross section spectra obtained as a result of this analysis are compared with the model assumptions. The simulations show that OSL signal can decrease to undetectable level even when the traps related to this signal are not emptied during thermal bleaching. The residual level of the OSL signal after bleaching process, however, depends strongly on centre parameters and concentrations. The modifications of optical detection spectral window lead to significant changes of bleaching effects. The thermal bleaching influences also the optical cross section spectra obtained as a result of the OSL curve decomposition.

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)

Assessing the completeness of optical resetting of quartz OSL in the natural environment

International Nuclear Information System (INIS)

Singarayer, J.S.; Bailey, R.M.; Ward, S.; Stokes, S.

2005-01-01

Resetting of previously accumulated optically stimulated luminescence (OSL) signals during transport of sediment is a fundamental requirement for reliable optical dating. The completeness of optical resetting of 46 modern-age quartz samples from a variety of depositional environments was examined. All equivalent dose (D e ) estimates were e from easy-to-bleach through to hard-to-bleach components. For all modern fluvial samples with non-zero D e values, SAR D e (t) analysis and component-resolved linearly modulated OSL (LM OSL) D e estimates showed this to be the case, implying incomplete resetting of previously accumulated charge. LM OSL measurements were also made to investigate the extent of bleaching of the slow components in the natural environment. In aeolian sediments examined, the natural LM OSL was effectively zero (i.e. all components were fully reset). The slow components of modern fluvial samples displayed measurable residual signals up to 15Gy

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)

A new fully automated TLD badge reader

International Nuclear Information System (INIS)

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

2003-01-01

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

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

International Nuclear Information System (INIS)

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

2016-01-01

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

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.

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

Science.gov (United States)

Sholom, S; McKeever, S W S

2016-09-01

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

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)

OSL Age Determination of the Hearths in a Bronze Age Dwelling Site by using Bayesian Statistics

International Nuclear Information System (INIS)

Kim, Myung Jin; Yang, Hye Jin; Hong, Duk Geun

2011-01-01

OSL dating for three hearths having the sequence of use and discard in No. 29 and 29-1 dwelling sites at Sogol cultural site was carried out. Resulting from the deconvolution of natural CW-OSL decay curve and thermal zeroing test, it was turned out that OSL signal was entirely composed of the heat- and light-sensitive fast component with high photoionization cross-section and all quartz OSL signals were thermally bleached under 300 .deg. C which is the minimum temperature related to heating and cooking in Bronze age. After dose recovery test and plateau test, paleodose of each hearth sample was evaluated by using SAR method, and OSL age was determined from the ratio of paleodose to annual dose rate. For the purpose of the precision improvement of OSL age, Bayesian statistics was applied to each hearth's age and the archaeological sequence information. Finally, it could be concluded to the accurate use period of each hearth from the resultant OSL ages

OSL Age Determination of the Hearths in a Bronze Age Dwelling Site by using Bayesian Statistics

Energy Technology Data Exchange (ETDEWEB)

Kim, Myung Jin [Neosiskorea Co. Ltd., Seoul (Korea, Republic of); Yang, Hye Jin [Baekje Cultural Properties Research Institute, Gongju (Korea, Republic of); Hong, Duk Geun [Kangwon National University, Chuncheon (Korea, Republic of)

2011-06-15

OSL dating for three hearths having the sequence of use and discard in No. 29 and 29-1 dwelling sites at Sogol cultural site was carried out. Resulting from the deconvolution of natural CW-OSL decay curve and thermal zeroing test, it was turned out that OSL signal was entirely composed of the heat- and light-sensitive fast component with high photoionization cross-section and all quartz OSL signals were thermally bleached under 300 .deg. C which is the minimum temperature related to heating and cooking in Bronze age. After dose recovery test and plateau test, paleodose of each hearth sample was evaluated by using SAR method, and OSL age was determined from the ratio of paleodose to annual dose rate. For the purpose of the precision improvement of OSL age, Bayesian statistics was applied to each hearth's age and the archaeological sequence information. Finally, it could be concluded to the accurate use period of each hearth from the resultant OSL ages.

Study of Optically Stimulated Luminescence of LiF:Mg,Ti for beta and gamma dosimetry

International Nuclear Information System (INIS)

Matsushima, Luciana C.; Veneziani, Glauco R.; Campos, Letícia L.

2013-01-01

Modern advances in radiation medicine – radiodiagnosis, radiotherapy and interventional radiography – each present dosimetry challenges for the medical physicist that did not exist previously. In all of these areas a constant balance has to be made between the treatment necessary to destroy the tumor and the unnecessary exposure of healthy tissue. Innovative applications of OSL dosimetry are now appearing in each of these areas to help the medical physicist and oncologist design the most effective, and least deleterious, treatment for their patients. High sensitivity, precise delivery of light, fast readout times, simpler readers and easier automation are the main advantages of OSL in comparison with TLD. This work aimed to study the application of OSL technique using lithium fluoride dosimeters doped with magnesium and titanium (LiF:Mg,Ti) for application in beta and gamma dosimetry. -- Highlights: •Study of Optically Stimulated Luminescence of LiF:Mg,Ti and microLiF:Mg,Ti. •OSL response of TLD-100 dosimeters to beta and gamma radiation. •Analysis of repeatability and lowest levels of detection of detectors LiF:Mg,Ti

Development of α - Al_2O_3:C films nanoparticulate for application in digital radiology

International Nuclear Information System (INIS)

Silva, Edna C.; Fontainha, Crissia C.; Ferraz, Wilmar B.; Faria, Luiz O.

2011-01-01

Phosphorescent ceramics are widely used in Ionizing radiation sensors. In nuclear applications, alpha-alumina doped with carbon (α-Al_2O_3: C) is most commonly used because of its excellent properties photoluminescent (OSL) and thermoluminescent (TL) in ionizing radiation detections. Another application of OSL and TL materials is the use in digital radiography. Recently, Computerized Radiography (CR) equipment, which use OSL materials, have been replacing the old X-ray devices. In this work we investigated the thermoluminescence of α-Al_2O_3 doped with different percentages of carbon, sintered in reducing atmospheres, in temperatures from 1300 to 1750 ° C. The results indicate that micro alumina doped with 0.5% of carbon and nano-alumina doped with 2% of carbon present TL signal of the order of 30 to 100 times the signal of the TLD-100, the most widely used TL dosimeter in the world. The results indicate that α-Al_2O_3: C nano-particulate has great potential for application in digital thermoluminescent radiography, because of its high TL response to radiation Ionization and the possibility of forming TL digital images with resolution increased by about 1000 times, depending on the size of the nanoparticles

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

International Nuclear Information System (INIS)

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

2010-01-01

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

The preliminary application of OSL in comparison with TL for authentication of ancient Chinese bricks

International Nuclear Information System (INIS)

Leung, P.L.; Tang Qiang; Li, Mike; Zhang Chunxiang

2005-01-01

The single-aliquot regenerative-dose (SAR) protocol with optically stimulated luminenscence (OSL) was applied to measure the equivalent dose (ED) of ancient Chinese bricks ranging in age from 180 to 1600 years. In the protocol, sensitivity changes can be corrected by using OSL response to a fixed test dose during measurement. For comparative study between OSL and TL, thermoluminescence (TL) measurement procedures were also applied to determine the paleodose of the bricks. Both results of OSL and TL are in agreement with the known ages of the bricks, and the paleodose ratios(ED OSL / ED TL ) are between 0.96 and 1.21, mean value 1.08+/-0.02. The annual doses of the bricks, estimated by the paleodoses and the known ages, range from 5.07 to 6.79mGy/a, comparable with the measured annual dose values of the bricks. Therefore, it is concluded that the SAR protocol is a rapid and effective OSL technique to authenticate Chinese bricks

A comparative study between OSL and TL techniques for the dating of ancient chinese bricks

International Nuclear Information System (INIS)

Leung, P.L.; Li, M.; Tang Qiang; Zhang Chunxiang

2004-01-01

The single-aliquot regenerative-dose (SAR) protocol to the optically stimulated luminescence (OSL) was applied to measure the paleodose of ancient Chinese bricks with an age range from 180 to 1600 years. In the protocol, sensitivity changes can be corrected by using OSL response to a fixed test dose during measurement. For comparative study between OSL and TL, thermoluminescence (TL) measurement procedures were also applied to determine the paleodose of the bricks. Both results of OSL and TL are in good agreement with, and the paleodose ratios (De OSL /De TL ) are between 0.96 and 1.21, with a mean value of 1.08 ± 0.07. The annual dose of the bricks, estimated by the paleodoses and the known ages, ranges from 5.07 to 6.85 mGy/a, comparable with the measured annual dose values. Therefore, it is concluded that the SAR protocol is a rapid and effective OSL technique to authenticate Chinese bricks. (authors)

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.)

Properties of lithium aluminate for application as an OSL dosimeter

International Nuclear Information System (INIS)

Twardak, A.; Bilski, P.; Marczewska, B.; Lee, J.I.; Kim, J.L.; Gieszczyk, W.; Mrozik, A.; Sądel, M.; Wróbel, D.

2014-01-01

Several samples of undoped and carbon or copper doped lithium aluminate (LiAlO 2 ) were prepared in an attempt to achieve a material, which can be applicable in optically stimulated luminescence (OSL) dosimetry. All investigated samples are highly sensitive to ionizing radiation and show good reproducibility. The undoped and copper doped samples exhibit sensitivity several times higher than that of Al 2 O 3 :C, while sensitivity of the carbon doped samples is lower. The studied samples exhibit significant fading, but dynamics of signal loss is different for differently doped samples, what indicates a possibility of improving this characteristic by optimizing dopant composition. - Highlights: • OSL properties of lithium aluminate for personal dosimetry. • Doping influence on OSL fading of lithium aluminate. • Application of lithium aluminate in thermal neutron measurements

OSL-thermochronometry using bedrock quartz: a note of caution

DEFF Research Database (Denmark)

Guralnik, B.; Ankjærgaard, Christina; Jain, Mayank

2015-01-01

Optically stimulated luminescence (OSL) thermochronometry is an emerging application, whose capability to record sub-Million-year thermal histories is of increasing interest to a growing number of subdisciplines of Quaternary research. However, several recent studies have encountered difficulties......, and may hamper successful OSL dating. Furthermore, even when the desirable signal is present, its concentration might be indistinguishable from its environmental steady-state prediction, thus preventing its conversion to a cooling or heating history. We explore the saturation properties and the thermal...

A comparison of single and multiple aliquot TT-OSL data sets for sand-sized quartz from the Arabian Peninsula

International Nuclear Information System (INIS)

Rosenberg, T.M.; Preusser, F.; Wintle, A.G.

2011-01-01

The quartz OSL signal from dune sands from Saudi Arabia and Oman start to saturate at doses of about 100 Gy. In order to try to date dune sands with greater expected doses, a previously published, single-aliquot, regenerative-dose protocol (SAR) for thermally-transferred optically stimulated luminescence (TT-OSL) was tested. Dose recovery tests, recycling and recuperation ratios showed robust functioning and dose response curves demonstrated the potential to extend the dose range to beyond 600 Gy. Multiple aliquot additive dose (MAAD) TT-OSL protocols were used to test for sensitivity changes in the SAR TT-OSL protocol up to doses of 1200 Gy. A strong dose dependent deviation of the SAR TT-OSL relative to the MAAD TT-OSL dose response is observed. Comparison of the TT-OSL and OSL sensitivity data obtained from the MAAD and SAR data sets shows a lack of proportionality between TT-OSL and OSL for the SAR data which will result in a problem when SAR dose response curves are constructed using many regeneration points with doses above 300 Gy.

Thermally and optically stimulated luminescence of AlN-Y2O3 ceramics after ionising irradiation

DEFF Research Database (Denmark)

Trinkler, L.; Bos, A.J.J.; Winkelman, A.J.M.

1999-01-01

, an essential drawback of AlN-Y2O3 is its high fading rate. Special attention has been focused on understanding and improving the fading properties. In particular, the influence of the ceramics production conditions and the additive concentration on the fading rate have been studied. Experimental results......Thermally (TL) and optically stimulated luminescence (OSL) were studied in AlN-Y2O3 ceramics after irradiation with ionising radiation. The extremely high TL sensitivity (approximately 60 times the sensitivity of LiF:Mg,Tl (TLD-100)) makes AlN-Y2O3 ceramics attractive as a TLD material. However...... on spectral properties and thermal evolution of OSL are also presented. The stimulation spectrum covers the spectral range from green to infrared light. A combination of thermal and optical stimulation allowed a correlation to be found between parameters of OSL and TL after the same irradiation dose...

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 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)

Luminescence characteristics of quartz from the Southern Kenyan Rift Valley: Dose estimation using LM-OSL SAR

International Nuclear Information System (INIS)

Choi, J.H.; Duller, G.A.T.; Wintle, A.G.; Cheong, C.-S.

2006-01-01

Linearly modulated (LM) optically stimulated luminescence (OSL) measurements have revealed that some sedimentary quartz samples from the Kenyan Rift Valley do not have a fast OSL component, but contain a medium component and several slow components. It was impossible to recover a known dose for these samples using the conventional single-aliquot regenerative-dose (SAR) procedure. The dose-response curves and continuous wave (CW) OSL decay curves for these samples showed several undesirable properties for dating. We have compared various luminescence characteristics of these samples with other quartz samples from elsewhere in the world for which the SAR procedure has been shown to be appropriate; the latter were dominated by a fast OSL component. The characteristics include photoionisation cross-sections for each component and the relative proportions of the different components in the initial and total OSL signals. It was found that those samples that had greater than 90% of the initial 0.8 s of their OSL signal from the fast component were suitable for dating using the conventional SAR protocol. A novel method of displaying the relative contributions of the different OSL components in a ternary diagram is proposed. The thermal stability of each component was investigated using pulse-annealing experiments. We then examined the possibility of applying an LM-OSL SAR protocol to samples that have a substantial medium component

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.

OSL response bleaching of BeO samples, using fluorescent light and blue LEDs

International Nuclear Information System (INIS)

Groppo, Daniela Piai; Caldas, Linda V.E.

2015-01-01

The optically stimulated luminescence (OSL) is widely used as a dosimetric technique for many applications. In this work, the OSL response bleaching of BeO samples was studied. The samples were irradiated using a beta radiation source ( 90 Sr+ 90 Y); the bleaching treatments (fluorescent light and blue LEDs) were performed, and the results were compared. Various optical treatment time intervals were tested until reaching the complete bleaching of the OSL response. The best combination of the time interval and bleaching type was analyzed. (author)

OSL response bleaching of BeO samples, using fluorescent light and blue LEDs

International Nuclear Information System (INIS)

Groppo, D P; Caldas, L V E

2016-01-01

The optically stimulated luminescence (OSL) is widely used as a dosimetric technique for many applications. In this work, the OSL response bleaching of BeO samples was studied. The samples were irradiated using a beta radiation source ("9"0Sr+"9"0Y); the bleaching treatments (fluorescent light and blue LEDs) were performed, and the results were compared. Various optical treatment time intervals were tested until reaching the complete bleaching of the OSL response. The best combination of the time interval and bleaching type was analyzed. (paper)

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

Correlation between TL and OSL properties of CaF2:N

International Nuclear Information System (INIS)

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

2006-01-01

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

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

International Nuclear Information System (INIS)

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

2002-10-01

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

Sample dependent correlation between TL and LM-OSL in Al2O3:C

International Nuclear Information System (INIS)

Dallas, G.I.; Polymeris, G.S.; Stefanaki, E.C.; Afouxenidis, D.; Tsirliganis, N.C.; Kitis, G.

2008-01-01

Al 2 O 3 :C single crystals are known to exhibit different, sample dependent, glow-curve shapes. The relation between the Thermoluminescence (TL) traps and the linear modulated optically stimulation luminescence (LM-OSL) traps is of high importance. In the present work a correlation study is attempted using 23 single crystals with dimensions between 400 and 500μm. The correlation study involved two steps. In the first step, both TL glow curves and LM-OSL decay curves are deconvoluted and a one-to-one correlation between TL peaks and LM-OSL components is attempted. In the second step the TL glow-curves are corrected for thermal quenching, the corrected curves are deconvoluted and a new correlation between TL and LM-OSL individual components is performed

Correlation of basic TL, OSL and IRSL properties of ten K-feldspar samples of various origins

Energy Technology Data Exchange (ETDEWEB)

Sfampa, I.K. [Aristotle University of Thessaloniki, Nuclear Physics Laboratory, 54124 Thessaloniki (Greece); Polymeris, G.S. [Institute of Nuclear Sciences, Ankara University, 06100 Besevler, Ankara (Turkey); Pagonis, V. [McDaniel College, Physics Department, Westminster, MD 21157 (United States); Theodosoglou, E. [Department of Mineralogy-Petrology-Economic Geology, School of Geology, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Tsirliganis, N.C. [Laboratory of Radiation Applications and Archaeological Dating, Department of Archaeometry and Physicochemical Measurements, ‘Athena’ R.& I.C., Kimmeria University Campus, GR67100 Xanthi (Greece); Kitis, G., E-mail: gkitis@auth.gr [Aristotle University of Thessaloniki, Nuclear Physics Laboratory, 54124 Thessaloniki (Greece)

2015-09-15

Highlights: • OSL and IRSL bleaching behavior of ten K-feldspar samples is presented. • OSL and IRSL decay curves were component resolved using tunneling model. • The growth of integrated OSL and IRSL signals versus time was described by new expression based on tunneling model. • Correlation between TL, OSL and IRSL signals and of all properties with K-feldspar structure was discussed. - Abstract: Feldspars stand among the most widely used minerals in dosimetric methods of dating using thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Having very good dosimetric properties, they can in principle contribute to the dating of every site of archaeological and geological interest. The present work studies basic properties of ten naturally occurring K-feldspar samples belonging to three feldspar species, namely sanidine, orthoclase and microcline. The basic properties studied are (a) the influence of blue light and infrared stimulation on the thermoluminescence glow-curves, (b) the growth of OSL, IRSL, residual TL and TL-loss as a function of OSL and IRSL bleaching time and (c) the correlation between the OSL and IRSL signals and the energy levels responsible for the TL glow-curve. All experimental data were fitted using analytical expressions derived from a recently developed tunneling recombination model. The results show that the analytical expressions provide excellent fits to all experimental results, thus verifying the tunneling recombination mechanism in these materials and providing valuable information about the concentrations of luminescence centers.

Thermal activation of OSL as a geothermometer for quartz grain heating during fault movements

CERN Document Server

Rink, W J; Rees-Jones, J; Schwarcz, H P

1999-01-01

In discussions of ESR dating of fault movements, there has been much debate whether zeroing of ESR signals is a mechanical shearing effect or caused by frictional heating. The OSL (optically stimulated luminescence) sensitivity of quartz is known to increase after heating. This thermal activation of dose response of the OSL in quartz should be useful as a geothermometer to test whether quartz particles in fault gouge had been heated. We tested the OSL sensitivities of quartz from fault gouge, and from a control (quartz grains from sandstone) and were able to show heat-induced enhancement of OSL sensitivity to a test dose. We observed that relative enhancement of OSL dose response (ratio of heated to unheated single aliquots) is significantly less for the finest grains (45-75 and 100-150 mu m) compared with coarser grains (150-250 mu m). These data are consistent with a model of zeroing of the quartz grains during faulting, by frictional heating localized to the grain boundaries, which would be expected to aff...

Pure thermal sensitisation and pre-dose effect of OSL in both unfired and annealed quartz samples

Energy Technology Data Exchange (ETDEWEB)

Oniya, Ebenezer O., E-mail: ebenezer.oniya@aaua.edu.ng [Physics and Electronics Department, Adekunle Ajasin University, 342111 Akungba Akoko (Nigeria); Polymeris, George S. [Institute of Nuclear Sciences, Ankara University, Beşevler 06100, Ankara (Turkey); Jibiri, Nnamdi N. [Department of Physics, University of Ibadan, Ibadan (Nigeria); Tsirliganis, Nestor C. [Department of Archaeometry and Physicochemical Measurements, R.C. ‘Athena’, P.O. Box 159, Kimmeria University Campus, 67100 Xanthi (Greece); Babalola, Israel A. [Department of Physics, University of Ibadan, Ibadan (Nigeria); Kitis, George [Nuclear Physics Laboratory, Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

2017-06-01

The sensitisation of quartz has attracted much attention since its thorough understanding is important in luminescence studies and dating applications. The present investigation examines the influence of pure thermal activation and predose treatments on the sensitisation of different components of linearly modulated optically stimulated luminescence (LM-OSL) measured at room temperature (RT) thereby eliminating undesired thermal quenching effects. Annealed and unfired quartz samples from Nigeria were used. The OSL measurements were carried out using an automated RISØTL/OSL reader (model-TL/OSL–DA–15). A new approach was adopted to match each of the resolved components of the RT-LM-OSL to respective thermoluminescence (TL) peaks that share the same electron trap and recombination centers. Pure thermal activation and pre-dose treatments respectively affect the sensitisation of all the components of the RT-LM-OSL in a similar manner as the one reported for the 110 °C TL peak but without thermal quenching contributions. Component C4 in annealed samples that was identified to share the same electron trap and recombination centers with the 110 °C TL peak was also proved appropriate for RT-LM-OSL, instead of the initial part of the continuous wave (CW) OSL signal, thus the methods can serve as complementary dating methods.

Pure thermal sensitisation and pre-dose effect of OSL in both unfired and annealed quartz samples

International Nuclear Information System (INIS)

Oniya, Ebenezer O.; Polymeris, George S.; Jibiri, Nnamdi N.; Tsirliganis, Nestor C.; Babalola, Israel A.; Kitis, George

2017-01-01

The sensitisation of quartz has attracted much attention since its thorough understanding is important in luminescence studies and dating applications. The present investigation examines the influence of pure thermal activation and predose treatments on the sensitisation of different components of linearly modulated optically stimulated luminescence (LM-OSL) measured at room temperature (RT) thereby eliminating undesired thermal quenching effects. Annealed and unfired quartz samples from Nigeria were used. The OSL measurements were carried out using an automated RISØTL/OSL reader (model-TL/OSL–DA–15). A new approach was adopted to match each of the resolved components of the RT-LM-OSL to respective thermoluminescence (TL) peaks that share the same electron trap and recombination centers. Pure thermal activation and pre-dose treatments respectively affect the sensitisation of all the components of the RT-LM-OSL in a similar manner as the one reported for the 110 °C TL peak but without thermal quenching contributions. Component C4 in annealed samples that was identified to share the same electron trap and recombination centers with the 110 °C TL peak was also proved appropriate for RT-LM-OSL, instead of the initial part of the continuous wave (CW) OSL signal, thus the methods can serve as complementary dating methods.

Relative response of TL and component-resolved OSL to alpha and beta radiations in annealed sedimentary quartz

International Nuclear Information System (INIS)

Polymeris, George S.; Afouxenidis, Dimitrios; Raptis, Spyridoula; Liritzis, Ioannis; Tsirliganis, Nestor C.; Kitis, George

2011-01-01

Knowledge of the relative luminescence response to alpha and beta radiation is very important in TL and OSL dating. In the present study the relative alpha to beta response is studied in a sedimentary quartz sample, previously fired at 900 deg. C for 1 h, in the dose region between 1 and 128 Gy, for both thermoluminescence (TL) and linearly modulated optically stimulated luminescence (LM - OSL). The LM - OSL measurements were performed at room temperature and at 125 deg. C. All OSL signals were deconvolved into their individual components. Comparison of OSL curves after alpha and beta irradiation strongly supports that quartz OSL components follow first order kinetics in both cases. In the case of TL, the relative alpha to beta response is found to be very different for each TL glow-peak, but it does not depend strongly on irradiation dose. In the case of LM - OSL measurements, it is found that the relative behaviour of the alpha to beta response is different for three distinct regions, namely the fast OSL component, the region of medium OSL component originating from the TL glow-peak at 110 deg. C when stimulation takes place at room temperature and finally the region of slow OSL component. Following stimulation at ambient temperature, the relative alpha to beta response of all components was not observed to depend significantly on dose, with the value of ratio being 0.03 and a tendency to decrease with increasing dose. However, in the case of measurements performed at 125 deg. C, the relative response of the fast components is much enhanced, and for the remaining components it increases with increasing dose. Special care must be taken to examine the relative alpha to beta response of the fast component at 125 deg. C which contrasts the relative response of the TL peak at ca. 325 deg. C. The implications for the dating of annealed quartz are also briefly discussed. - Highlights: → Relative alpha to beta response for TL and LM-OSL is studied in annealed

Towards an automated TLD system that meets international requirements

International Nuclear Information System (INIS)

Boetter-Jensen, L.; Vanamo, V.

1988-01-01

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

Sources of uncertainty in individual monitoring for photographic,TL and OSL dosimetry techniques

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Max S.; Silva, Everton R.; Mauricio, Claudia L.P., E-mail: max.das.ferreira@gmail.com, E-mail: everton@ird.gov.br, E-mail: claudia@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2015-07-01

The identification of the uncertainty sources and their quantification is essential to the quality of any dosimetric results. If uncertainties are not stated for all dose measurements informed in the monthly dose report to the monitored radiation facilities, they need to be known. This study aims to analyze the influence of different sources of uncertainties associated with photographic, TL and OSL dosimetric techniques, considering the evaluation of occupational doses of whole-body exposure for photons. To identify the sources of uncertainty it was conducted a bibliographic review in specific documents that deal with operational aspects of each technique and the uncertainties associated to each of them. Withal, technical visits to individual monitoring services were conducted to assist in this identification. The sources of uncertainty were categorized and their contributions were expressed in a qualitative way. The process of calibration and traceability are the most important sources of uncertainties, regardless the technique used. For photographic dosimetry, the remaining important uncertainty sources are due to: energy and angular dependence; linearity of response; variations in the films processing. For TL and OSL, the key process for a good performance is respectively the reproducibility of the thermal and optical cycles. For the three techniques, all procedures of the measurement process must be standardized, controlled and reproducible. Further studies can be performed to quantify the contribution of the sources of uncertainty. (author)

Luminescence properties of Eu{sup 2+} doped SrB{sub 4}O{sub 7} phosphor for radiation dosimetry

Energy Technology Data Exchange (ETDEWEB)

Palan, C.B., E-mail: chetanpalan27@yahoo.in; Bajaj, N.S.; Omanwar, S.K.

2016-04-15

Highlights: • Report TL/OSL properties of SrB{sub 4}O{sub 7}:Eu{sup 2+} under beta irradiations. • OSL Sensitivity was about 33% than that of commercially available α-Al{sub 2}O{sub 3.} • TL glow peaks was appear at 305° C and TL sensitivity about 200 times higher than TLD-500. • OSL decay pattern was faster than α- Al{sub 2}O{sub 3}:C and dose response was linear nature. - Abstract: In this report, we presented the TL/OSL properties of Eu doped SrB{sub 4}O{sub 7} phosphor under β-irradiation. This phosphor was synthesized by using solid state method. The phosphor shows OSL sensitivity about 33% than that of commercially available α-Al{sub 2}O{sub 3}: C phosphor. CW-OSL curve possess two components having photoionization cross-sections 0.707 × 10{sup −17} and 18.58 × 10{sup −17} cm{sup 2} respectively and TL sensitivity about 200 times higher than TLD-500. The kinetic parameters such as activation energy, frequency factor and order of kinetics of TL curve were calculated by using peak shape method. In TL/OSL mode dose-response was almost linear in the range of measurements. The MDD was found to be 1.26 mGy with 3σ of background. Also reusability studies showed the phosphor can be reused for 10 cycles with 1% change in the OSL output. The PL spectra of SrB{sub 4}O{sub 7} showed emission in NUV region when excited with 318 nm under UV source.

Firing temperature of pottery using TL and OSL techniques

International Nuclear Information System (INIS)

Polymeris, G.S.; Sakalis, A.; Papadopoulou, D.; Dallas, G.; Kitis, G.; Tsirliganis, N.C.

2007-01-01

Several methods of thermal analysis are used to determine in the laboratory the firing temperature of ancient ceramic sherds. These methods are based primarily on changes of physical characteristics occurring when clay minerals are heated. The luminescence properties of quartz grains in a ceramic matrix also undergo certain changes during firing. The possibility of measuring the sensitivity change (sensitization) of quartz in order to determine the firing temperature of archeological ceramic artifacts was investigated. The sensitivity change was studied for both the thermoluminescence (TL) and the optically stimulated luminescence (OSL) signal for a ceramic sample of known firing temperature. Various segments of the sample were annealed to a different temperature. Subsequently, the initial sensitivity, as well as the thermal and the pre-dose sensitization were measured for both TL and OSL at room temperature as a function of the annealing temperature. The obtained TL glow curves showed different shapes for annealing temperatures above the firing temperature. Thermal and pre-dose sensitizations also exhibited a similar, although less prominent, rise. The OSL signal was analyzed by integrating the raw signal over the initial second of stimulation. The initial sensitivity showed an abrupt change for annealing temperatures around the firing temperature. An alternative approach used for the analysis of the OSL signal involved a full-component resolved sensitization study. The same abrupt change for the initial sensitivity of both the first and second components was observed, as well as, a clear but not very prominent thermal sensitization trend for annealing temperatures above the firing temperature

OSL and IRSL characteristics of quartz and feldspar from southern California, USA

International Nuclear Information System (INIS)

Lawson, Michael J.; Roder, Belinda J.; Stang, Dallon M.; Rhodes, Edward J.

2012-01-01

Southern California comprises of a wide range of diverse landscapes and environments, from high mountains with glacial and periglacial sediments to deserts with large sand dunes, extensive alluvial fans and ephemeral playas. Highly active tectonic processes has exposed ancient (c. 2 Ga) plutonic and metamorphic basement from deep within the crust, while similar Palaeozoic, Mesozoic and Cenozoic rocks are also common. A rich array of volcanic lithologies extending into the late Quaternary complement many thick sedimentary sequences that formed in equally diverse ancient environments typical of an accreting active continental margin. In some locations, notably in the Coachella Valley close to Palm Springs and the Salton Sea, low OSL sensitivity and poor characteristics restrict the application of the quartz SAR protocol to date late Pleistocene and Holocene fluvial sediments. In other locations such as the Malibu coastline, high sensitivity of the quartz OSL signal is observed, despite local source rocks being dominated by volcanic lithologies. Problems of poor quartz characteristics, along with uncertainty in predicting quartz OSL behavior for future dating campaigns poses a significant problem for projects, in particular for neotectonic contexts. While K-feldspar has been used extensively to date eolian and fluvial sediments in southern California, little information regarding signal stability is available. We explore the characteristics of both quartz and feldspar sub-samples from eolian, fluvial, lacustrine environments, in order to help develop mineral selection criteria for optical dating applications and clarify these issues. The importance of radiation quenching in quartz grains recently eroded from bedrock and the role of fires in enhancing OSL sensitivity are considered. The relative bleachability of quartz and feldspar fractions, along with thermal stability considerations is discussed. A simple test for quartz OSL signal contamination based on thermal

OSL surface exposure dating of a lithic quarry in Tibet: Laboratory validation and application

DEFF Research Database (Denmark)

Gliganic, L.A.; Meyer, M.C.; Sohbati, R.

2018-01-01

developed OSL Surface exposure dating technique (OSL-Surf) to date flake scars at lithic quarry sites. We performed the first quantitative validation of the model describing the OSL-Surf dating technique using a controlled laboratory experiment. Our results show that longer laboratory bleaching durations......-depth profile that could be used to calibrate the model to estimate the exposure duration of a flake scar associated with human exploitation of the area. Finally, we observe that the μ parameter of the OSL-Surf model varies considerably between the laboratory-bleached and two naturally daylight-bleached...... datasets, despite having identical lithologies. We thus infer that, in addition to lithological controls, the μ parameter is primarily sensitive to the daylight irradiation geometry and only weakly dependent on spectrum of the incident light; this interpretation implies a narrow effective bleaching...

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

OSL, TL and IRSL emission spectra of sedimentary quartz and feldspar samples

International Nuclear Information System (INIS)

Lomax, Johanna; Mittelstraß, Dirk; Kreutzer, Sebastian; Fuchs, Markus

2015-01-01

This contribution presents a variety of different luminescence emission spectra from sedimentary feldspar and quartz samples under various stimulation modes. These are green stimulated quartz (OSL-) spectra, quartz TL spectra, feldspar IRSL and post-IR IRSL spectra. A focus was set at recording OSL and IRSL spectra at elevated stimulation temperatures such as routinely applied in luminescence dating. This was to test whether optical stimulation at elevated temperatures results in a shift of emission peaks. For OSL emissions of quartz, this has so far not been tested. In case of feldspar emissions, post-IR IRSL conditions, hence IRSL emissions at a low temperature, directly followed by high temperature post-IRSL emissions, are explicitly investigated. All spectra were recorded using a new system incorporated into a Lexsyg luminescence reader. Thus, this study, besides presenting new spectral data, also serves as a feasibility study for this new device. It is shown that (a) the new device is capable of automatically measuring different sorts of spectra, also at elevated temperatures, (b) known thermally and optically stimulated peak emissions of quartz and feldspar are confirmed, (c) obtained IRSL and OSL spectra indicate that there is no significant relation between peak emission and stimulation temperature. - Highlights: • We have measured OSL, IRSL and TL emission spectra of sedimentary quartz and feldspar samples. • Spectral analyses were performed at elevated stimulation temperatures. • Emission spectra show very little variation with stimulation temperatures.

TL and OSL studies of carbon doped magnesium aluminate (MgAl2O4:C)

Science.gov (United States)

Raj, Sanu S.; Mishra, D. R.; Soni, Anuj; Grover, V.; Polymeris, G. S.; Muthe, K. P.; Jha, S. K.; Tyagi, A. K.

2016-10-01

The MgAl2O4:C has been synthesized by using two different methods by electron gun and vacuum assisted melting of MgAl2O4 in presence of graphite. The MgAl2O4:C phosphor thus developed by these two different methods have similar types of the TL/OSL defects with multiple overlapping TL glow peaks from 100 °C to 400 °C. The Computerized Curve De-convolution Analysis (CCDA) has been used to measure TL parameters such as thermal trap depth, frequency factor and order of kinetic associated with charge transfer process in TL phenomenon. The investigated TL/OSL results show that these two methods of incorporating carbon in MgAl2O4 have generated closely resemble the defects of similar types in MgAl2O4:C lattice. However, the MgAl2O4:C synthesized by electron gun shows relatively larger concentration of the TL/OSL defects as compared to MgAl2O4:C synthesized using vacuum assisted melting method. The photo-ionization cross-section (PIC) associated with fastest OSL component of MgAl2O4: C is found to be ∼ 0.5 times than that of fastest OSL component of commercially available dosimetric grade α-Al2O3:C. The MgAl2O4:C thus developed shows good dynamic OSL dose linearity from few mGy to 1 Gy. This work reveals that MgAl2O4:C could be developed as potential tissue equivalent OSL / TL material.

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

LM-OSL signals from some insulators: an analysis of the dependency of the detrapping probability on stimulation light intensity

DEFF Research Database (Denmark)

Bulur, E.; Bøtter-Jensen, L.; Murray, A.S.

2001-01-01

Optically stimulated luminescence (OSL) signals from various insulators including quartz, Al2O3 : C, BeO and NaCl have been studied using the linear modulation OSL (LM-OSL) technique. LM-OSL is based on the linear increase of the stimulation light power from zero to a maximum during the measurement...... is not always correct. The initial decay rates of the blue (similar to 470 nm) light stimulated constant power OSL decay curves were examined to test the relation between the detrapping rates and the stimulation light intensity. In SiO2, Al2O3 : C and BeO a linear relation between the detrapping rates....... The resultant OSL curve initially increases and then decays after reaching a maximum, The analysis of LM-OSL data usually assumes a linear relationship between the detrapping rate and the stimulation light intensity. However, experiments carried out using various insulators have shown that this assumption...

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

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

International Nuclear Information System (INIS)

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

2003-01-01

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

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)

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

Optically stimulated luminescence (OSL) from Ag-doped Li2B4O7 crystals

International Nuclear Information System (INIS)

Kananen, B.E.; Maniego, E.S.; Golden, E.M.; Giles, N.C.; McClory, J.W.; Adamiv, V.T.; Burak, Ya.V.; Halliburton, L.E.

2016-01-01

Optically stimulated luminescence (CW-OSL) is observed from Ag-doped lithium tetraborate (Li 2 B 4 O 7 ) crystals. Photoluminescence, optical absorption, and electron paramagnetic resonance (EPR) are used to identify the defects participating in the OSL process. As-grown crystals have Ag + ions substituting for Li + ions. They also have Ag + ions occupying interstitial sites. During a room-temperature exposure to ionizing radiation, holes are trapped at the Ag + ions that replace Li + ions and electrons are trapped at the interstitial Ag + ions, i.e., the radiation forms Ag 2+ (4d 9 ) ions and Ag 0 (4d 10 5s 1 ) atoms. These Ag 2+ and Ag 0 centers have characteristic EPR spectra. The Ag 0 centers also have a broad optical absorption band peaking near 370 nm. An OSL response is observed when the stimulation wavelength overlaps this absorption band. Specifically, stimulation with 400 nm light produces an intense OSL response when emission is monitored near 270 nm. Electrons optically released from the Ag 0 centers recombine with holes trapped at Ag 2+ ions to produce the ultraviolet emission. The OSL response is progressively smaller as the stimulation light is moved to longer wavelengths (i.e., away from the 370 nm peak of the absorption band of the Ag 0 electron traps). Oxygen vacancies are also present in the Ag-doped Li 2 B 4 O 7 crystals, and their role in the OSL process as a secondary relatively short-lived electron trap is described.

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)

OSL dating of sediments from Negro and Solimões rivers – Amazon, Brazil

International Nuclear Information System (INIS)

Fiore, M.; Soares, E.A.A.; Mittani, J.C.R.; Yee, M.; Tatumi, S.H.

2014-01-01

In this work, the OSL dating results of Quaternary fluvial deposits from the confluence of Negro and Solimões rivers were studied. The equivalent doses (D e ) of sediments were obtained using a Single Aliquot Regeneration (SAR) protocol. Statistic studies were made using frequency histogram, weighted histogram and Radial plot in order to analyze the D e fluctuations. Ages from 74.5 to 205 thousand of years (Pleistocene) were recorded. The gamma-ray spectroscopy was used to evaluate the natural radioisotopes concentrations of the samples and low concentrations were found with values between 0.64 and 3.71 ppm for 235 U and 238 U; 2.01–9.77 ppm for 232 Th; already, for 40 K, the concentration was negligible. The OSL dating of sediments has contributed to a better understanding of the evolution of Negro and Solimões rivers, in Amazon, Brazil. - Highlights: ► OSL dating of fluvial terraces from Amazon. ► SAR protocols applied to Amazon sediments dating. ► OSL dating of Solimão and Negro rivers sediments

Mechanical properties of rubberwood oriented strand lumber (OSL: The effect of strand length

Directory of Open Access Journals (Sweden)

Buhnnum Kyokong

2005-09-01

Full Text Available Effect of strand length on mechanical properties (tension, compression and bending of oriented strand lumber (OSL made of rubberwood (Hevea brasiliensis Muell. Arg. was reported. Three strand lengths of 50 mm, 100 mm, and 150 mm with 1 mm thickness and 15 mm width were used. The strands were mixed with 5% pMDI glue (weight basis in a tumble mixer. The OSL specimens were formed by hot pressing process of unidirectionally aligned strands. Average specific gravity and moisture content were 0.76 and 8.34%, respectively. Tension and compression tests were carried out for directions both parallel and perpendicular to grain while bending test was performed only in parallel direction. Ultimate stresses and moduli of elasticity were examined from the stress-strain curves. It was found that for the parallel-to-grain direction, the longer strand OSL gave higher strength. The role of the strand length did not appear for the direction normal to the grain. The relationship between the mechanical properties of OSL and strand length was well described by the modified Hankinson formula.

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

BeO-OSL detectors for dose measurements in cell cultures

International Nuclear Information System (INIS)

Andreeff, M.; Freudenberg, R.; Kotzerke, J.; Sommer, D.; Reichelt, U.; Henniger, J.

2009-01-01

Aim: The absorbed dose is an important parameter in experiments involving irradiation of cells in vitro with unsealed radionuclides. Typically, this is estimated with a model calculation, although the results thus obtained cannot be verified. Generally used real-time measurement methods are not applicable in this setting. A new detector material with in vitro suitability is the subject of this work. Methods: Optically-stimulated luminescence (OSL) dosimeters based on beryllium oxide (BeO) were used for dose measurement in cell cultures exposed to unsealed radionuclides. Their qualitative properties (e. g. energy-dependent count rate sensitivity, fading, contamination by radioactive liquids) were determined and compared to the results of a Monte Carlo simulation (using AMOS software). OSL dosimeters were tested in common cell culture setups with a known geometry. Results: Dose reproducibility of the OSL dosimeters was ± 1.5%. Fading at room temperature was 0.07% per day. Dose loss (optically-stimulated deletion) under ambient lighting conditions was 0.5% per minute. The Monte Carlo simulation for the relative sensitivity at different beta energies provided corresponding results to those obtained with the OSL dosimeters. Dose profile measurements using a 6 well plate and 14 ml PP tube showed that the geometry of the cell culture vessel has a marked influence on dose distribution with 188 Re. Conclusion: A new dosimeter system was calibrated with β-emitters of different energy. It turned out as suitable for measuring dose in liquids. The dose profile measurements obtained are suitably precise to be used as a check against theoretical dose calculations. (orig.)

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

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)

The fast ratio: A rapid measure for testing the dominance of the fast component in the initial OSL signal from quartz

International Nuclear Information System (INIS)

Durcan, Julie A.; Duller, Geoff A.T.

2011-01-01

The signal from the fast component is usually considered preferable for quartz optically stimulated luminescence (OSL) dating, however its presence in a continuous wave (CW) OSL signal is often assumed, rather than verified. This paper presents an objective measure (termed the fast ratio) for testing the dominance of the fast component in the initial part of a quartz OSL signal. The ratio is based upon the photo ionisation cross-sections of the fast and medium components and the power of the measurement equipment used to record the OSL signal, and it compares parts of the OSL signal selected to represent the fast and medium components. The ability of the fast ratio to distinguish between samples whose CW-OSL signal is dominated by the fast and non-fast components is demonstrated by comparing the fast ratio with the contribution of the fast component calculated from curve deconvolution of measured OSL signals and from simulated data. The ratio offers a rapid method for screening a large number of OSL signals obtained for individual equivalent dose estimates, it can be calculated and applied as easily as other routine screening methods, and is transferrable between different aliquots, samples and measurement equipment. - Highlights: → Fast ratio is a measure which tests dominance of fast component in quartz OSL signals. → A fast ratio above 20 implies a CW-OSL signal is dominated by fast component. → Fast ratio can be easily and rapidly applied to a large number of OSL signals. → Uses include signal comparison, data screening, identify need for further analysis.

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

Energy Technology Data Exchange (ETDEWEB)

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

2011-07-01

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

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

International Nuclear Information System (INIS)

Ekendahl, Daniela; Judas, Libor; Sukupova, Lucie

2013-01-01

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

Thermal activation of OSL as a geothermometer for quartz grain heating during fault movements

International Nuclear Information System (INIS)

Rink, W.J.; Toyoda, S.; Rees-Jones, J.; Schwarcz, H.P.

1999-01-01

In discussions of ESR dating of fault movements, there has been much debate whether zeroing of ESR signals is a mechanical shearing effect or caused by frictional heating. The OSL (optically stimulated luminescence) sensitivity of quartz is known to increase after heating. This thermal activation of dose response of the OSL in quartz should be useful as a geothermometer to test whether quartz particles in fault gouge had been heated. We tested the OSL sensitivities of quartz from fault gouge, and from a control (quartz grains from sandstone) and were able to show heat-induced enhancement of OSL sensitivity to a test dose. We observed that relative enhancement of OSL dose response (ratio of heated to unheated single aliquots) is significantly less for the finest grains (45-75 and 100-150 μm) compared with coarser grains (150-250 μm). These data are consistent with a model of zeroing of the quartz grains during faulting, by frictional heating localized to the grain boundaries, which would be expected to affect smaller grains more than large ones. This argues against a zeroing model in which the entire fault gouge is heated by friction. Higher laboratory preheating of sandstone quartz reduces between-aliquot variability of OSL dose response in the unheated grains to nearly zero. Unheated coarsest fault gouge grains displayed virtually no among-aliquot variability, whereas fine grains showed much larger between-aliquot variability; as with the quartz sand, variability dropped to near zero after laboratory heating, suggesting that fine grains in fault gouge have experienced a wide range of natural thermal histories during faulting. This may present a problem for ESR dating of fault gouge using the plateau method

Application of the OSL dosimetry technique in the identification of irradiated foods, such as condiments and spices

International Nuclear Information System (INIS)

Silva, Catherine C.O.; Alencar, Marcus A.V. de

2013-01-01

The use of ionizing radiation in food preservation is considered a well-established technique, so many countries, including Brazil, now allow the use of irradiated foods. Many methods have been tested for dosimetry and identification of irradiated foods including thermoluminescence, electron paramagnetic resonance, and others based on microbiological changes and in viscosity, and which requires a sample processing. The technique of optically stimulated luminescence (OSL) presents an advantage over other methods mentioned: The samples may be used without the need for a prior processing. This work aims to study the OSL properties of condiments and spices irradiated, in order to verify the possibility of the application of the OSL technique in identifying and dosimetry of irradiated foods. The samples used were of four kinds of spices: cumin, oregano, white pepper and black pepper. All samples were subjected to gamma irradiation from a Co-60 source with dose values of kerma in air of 100 Gy to 35 kGy. The samples of cumin presents the OSL signal, however, is only possible to identify whether the condiment was irradiated or not. The sample of oregano also presents the OSL signal, and for this condiment is possible to identify addition to its irradiation, the value of dose. The black pepper and white pepper samples don't presents the OSL signal. The results obtained in this study indicate the possibility of using the OSL technique for the identification and dosimetry of irradiated foods. (author)

Detection of sub micro Gray dose levels using OSL phosphor LiMgPO_4:Tb,B

International Nuclear Information System (INIS)

Rawat, N.S.; Dhabekar, Bhushan; Muthe, K.P.; Koul, D.K.; Datta, D.

2017-01-01

Highlights: • LiMgPO4:Tb,B has been studied and shown to possesses minimum measurable dose (MMD) in sub micro Gray region. • MMD as low as 0.49 µGy in readout time of less than 1 s at stimulation intensity of 32 mW/cm"2 has been achieved. • The OSL measurements for low doses has strengthened and validated this claim. • OSL spectrum shows several emission peaks and the prominent peak around 380 nm. - Abstract: Detection of sub micro Gray doses finds application in personnel and environmental monitoring, and nuclear forensics. Recently developed LiMgPO_4:Tb,B (LMP) is highly sensitive Optically Stimulated Luminescence (OSL) phosphor with excellent dosimetric properties. The OSL emission spectrum of LMP consists of several peaks attributed to characteristic Tb"3"+ emission. The OSL emission peak at 380 nm is favorable for bi-alkali PMT used in RISO reader system. It is demonstrated that significant improvement in dose detection threshold can be realized for LMP by optimization of continuous wave (CW–) OSL parameters like stimulation intensity and readout time. The minimum measurable dose (MMD) as low as 0.49 µGy in readout time of less than 1 s at stimulation intensity of 32 mW/cm"2 has been achieved using this phosphor. The recommendations for choice of parameters for personnel and environmental monitoring are also discussed.

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.

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%.

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

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)

On the OSL curve shape and preheat treatment of electronic components from portable electronic devices

DEFF Research Database (Denmark)

Woda, Clemens; Greilich, Steffen; Beerten, Koen

2010-01-01

The shape of the OSL decay curve and the effect of longer time delays between accidental exposure and readout of alumina-rich electronic components from portable electronic devices are investigated. The OSL decay curve follows a hyperbolic decay function, which is interpreted as an approximation ...

OSL signal of IC chips from mobile phones for dose assessment in accidental dosimetry

International Nuclear Information System (INIS)

Mrozik, A.; Marczewska, B.; Bilski, P.; Książek, M.

2017-01-01

The rapid assessment of the radiation dose is very important for the prediction of biological effects after unintended exposition. The materials for use as dosimeters in accidental dosimetry should be everyday objects which are usually placed near the human body, for example mobile phones. IC (Integrated Circuit) chip is one of several electronic components of mobile phones which give a luminescent signal. The measurements of samples from different mobile phones and smartphones were conducted by optically stimulated luminescence (OSL) and thermoluminescence (TL) methods. The OSL measurement was performed in two ways: with readouts at room temperature and at 100 °C. This work is focused on determination of OSL dose response of IC chips, minimum detectable dose (MDD), OSL signal stability in the time after the exposition, its repeatability and sensitivity to light. Several tests of the assessment of unknown doses were also conducted. The readouts at 100 °C indicate the reducing of the fading of OSL signal in the first hours after irradiation in comparison with room temperature readouts. The obtained results showed relatively good dosimetric properties of IC chips: their high sensitivity to the ionizing radiation, linear dose response up to 10 Gy and a good reproducibility of OSL signal which can allow the dose recovery of doses less than 2 Gy in 14 days after an incident with the accuracy better than 25%. The fading is a drawback of IC chips and the fading factor should be considered when calculating the dose. - Highlights: • IC chips from smartphones demonstrated high potential for accidental dosimetry. • Minimum detectable dose was estimated as a value of 50 mGy. • Samples showed linear dose response for the dose range from 0.05 Gy up to 10 Gy.

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.

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

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

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

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%.

Pulse and integral optically stimulated luminescence (OSL). Similarities and dissimilarities to thermoluminescence (TL) dose dependence and dose-rate effects

International Nuclear Information System (INIS)

Chen, R.; Leung, P.L.

2000-01-01

Optically stimulated luminescence (OSL) and thermoluminescence (Tl) are two possible methods to monitor the absorbed radiation in solid samples, and therefore are utilized for dosimetry. For this application, two properties are desirable, namely, linear dose dependence of the measured quantity and dose-rate independence. For Tl, different kinds of super linear dose dependence have been reported in the literature in different materials, and in some cases, dose-rate dependence has also been found. These have been explained as being the result of competition. In OSL, some recent works reported on super linear dose dependence in annealed samples. In the present work, we explain the possible occurrence of these phenomena in OSL by solving numerically the relevant rate equations governing the process during irradiation, relaxation and read-out (heating or light stimulation). The results show that for short pulse OSL, quadratic dose dependence can be expected when only one trapping state and one kind of recombination center are involved and when the excitation starts with empty traps and centers. With the short pulse OSL, the calculation also reveals a possible dose-rate effect. Under the same circumstances, the area under the OSL curve depends linearly on the dose. The dependence of the whole area under the OSL curve on the dose is shown to be super linear when a disconnected trapping state or radiationless center take part in the process. Also, dose-rate effect can be expected in these cases, although no experimental effect of this sort has been reported so far. In pulse OSL, the analogy is made between the measured intensity and the initial rise range of non-first order Tl, whereas for the total area OSL, there is a nearly full analogy with the dose behavior of the Tl maximum. (Author)

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

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)

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

Potential and limits of OSL, TT-OSL, IRSL and pIRIR290 dating methods applied on a Middle Pleistocene sediment record of Lake El'gygytgyn, Russia

Directory of Open Access Journals (Sweden)

A. Zander

2013-03-01

Full Text Available This study tests the paleomagnetic and proxy-data based Mid- to Upper Pleistocene sediment deposition history of Lake El'gygytgyn by applying different approaches of luminescence dating techniques on sediment cores taken from the centre of the 175 m deep lake. For dating polymineral and quartz fine grains (4–11 μm grain size range were extracted from nine different levels from the upper 28 m of sediment cores 5011-1A and 5011-1B. According to the independent age model, the lowest sample from 27.8–27.9 m below lake bottom level correlates to the Brunhes-Matuyama (B/M reversal. Polymineral sub-samples were analysed by infra-red stimulated luminescence (IRSL and post-IR IRSL measured at 290 °C (pIRIR290 using single aliquot regenerative dose (SAR sequences. SAR protocols were further applied to measure the blue light optically stimulated luminescence (OSL and thermally-transferred OSL (TT-OSL of fine-grained quartz supplemented by a multiple aliquot approach. Neither low temperature IRSL measurements at 50 °C nor any OSL dating approach on quartz yielded reliable results. Deconvolution of their dose response curves revealed a pseudo-increase of the dose response curves and explains the observed underestimation. The pIRIR protocol applied to polymineral fine grains was the only luminescence technique able to provide dating results of acceptable accuracy up to ca. 700 ka when correlated to the existing proxy-data and paleomagnetic based age record. We present the potential and limits of the different dating techniques and a correlation of pIRIR290 results with the proxy-data based age model.

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

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

Energy Technology Data Exchange (ETDEWEB)

NONE

2016-06-15

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-06-15

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

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

International Nuclear Information System (INIS)

Kry, S.

2016-01-01

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

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

International Nuclear Information System (INIS)

2016-01-01

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

Optical stimulated luminescence (OSL) dating

International Nuclear Information System (INIS)

Banerjee, D.

1999-01-01

Since the pioneering work by Huntley et al. (1985), optical dating is being increasingly recognised as an important technique for establishing a time frame of deposition of sediments (Aitken, 1998). Optical dating differs from thermoluminescence (TL) dating in that visible/infrared light from lasers or LEDs (light-emitting-diodes) is used as a means of stimulation, in contrast to thermal stimulation. It has several advantages over TL dating: (i) the resetting of the OSL (optically stimulated luminescence) clock is more effective than that of TL clock; for sediments transported under water or in other situations where the sediment grains have undergone inhomogeneous bleaching, this property ensures that ages based on optical dating are generally more reliable than TL ages, (ii) the optical dating technique is non-destructive, and multiple readouts of the optical signal is possible; this feature has resulted in the development of single-aliquot and single-grain protocols (Murray and Wintle, 1999; Banerjee et al. 1999), (iii) the sample is not heated as in TL; thus, spurious luminescence is avoided and there is a significant reduction in blackbody radiation. Dating of materials which change phase on heating is also practical, and finally, (iv) thermal quenching of luminescence is negligible, allowing accurate estimation of kinetic parameters using standard techniques and providing access to deep OSL traps. This characteristic may be helpful in extending the limits of optical dating beyond the last 150 ka from a global point of view

The correlation of fast OSL component with the TL peak at 3250C in quartz of various origins

International Nuclear Information System (INIS)

Kitis, G.; Kiyak, N.; Polymeris, G.S.; Tsirliganis, N.C.

2010-01-01

The fast component of the optically stimulated luminescence (OSL) signal in quartz is the basic tool for the optical dating. Its relation with the thermoluminescence (TL) glow-peak at about 325 deg. C is well established for naturally irradiated quartz. This relationship is also an important part of a general model for quartz on which many theoretical simulations of various OSL experimental results have been based. In the present work this relationship is systematically investigated in nine quartz samples of different origin. The linearly modulated OSL (LM-OSL) curves of all quartz samples for stimulation time less than 50 s consists of two components discriminated easily by a computerized curve deconvolution (CCD) analysis. By comparing the un-bleached to the respective bleached TL glow-curve, it is found that the system of these two fast OSL components is directly related with only a small portion of the electron traps responsible for the TL glow-peaks in the temperature region 200-400 0 C. By increasing the stimulation times, besides the two fast components, the medium and the slow components are also obtained. The medium and slow components are clearly related with the main body of the electron traps responsible for TL glow-peaks in the same temperature region 200-400 0 C. Despite their different origin all quartz samples show an appreciable homogeneity concerning the number and time position of the individual components, whereas, the relative TL/OSL intensities vary strongly from sample to sample with the integrated TL intensity being generally much less than the integrated OSL intensity.

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)

The dependence of dose recovery experiments on the bleaching of natural quartz OSL using different light sources

International Nuclear Information System (INIS)

Choi, J.H.; Murray, A.S.; Cheong, C.-S.; Hong, S.C.

2009-01-01

In this paper, the dependence of dose recovery tests on the different bleaching light sources (blue-LEDs, solar simulator, natural sunlight) is investigated with a variety of sedimentary quartz samples, selected so that their OSL signals are dominated by the fast OSL component. We observed that when long solar simulator bleaching was applied, various known doses were underestimated in an SAR-based dose recovery test. However, when blue-LEDs and short solar simulator bleaching were used (10 s and 60 s) the known doses were accurately recovered. In repeated measurement of the OSL signals induced by the same regeneration and test dose, we observed a considerable increase in quartz OSL sensitivity during or after the first OSL measurement when long solar simulator bleaching was used; this seems to provide a possible explanation for the observed underestimation of the laboratory known doses. A series of experimental results using a sample from a modern aeolian dune surface shows that there are no subsequent sensitivity changes when the naturally zeroed samples are bleached with sunlight for long time. It seems that there is a dependence of the sensitivity change on the amount of dose administered before solar simulator bleaching and on the light intensity of solar simulator. When small doses were given to the naturally zeroed sample, the sensitivity change during or after the first OSL measurement was not significant. However, when a considerable amount of beta dose (∼4000 Gy) is administered to the sample, a clear sensitivity change during or after the first OSL measurement (∼20%) was observed. Such a sensitivity change was not observed when the bleaching light intensity of solar simulator was reduced by increasing the distance between samples and the UV lamp. Our results show that, at least for the samples described here, the outcomes of dose recovery experiments are dependent on the bleaching conditions.

Detection of sub micro Gray dose levels using OSL phosphor LiMgPO{sub 4}:Tb,B

Energy Technology Data Exchange (ETDEWEB)

Rawat, N.S., E-mail: naru@barc.gov.in [Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Trombay, Mumbai (India); Dhabekar, Bhushan [Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Trombay, Mumbai (India); Muthe, K.P. [Technical Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai (India); Koul, D.K.; Datta, D. [Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Trombay, Mumbai (India)

2017-04-15

Highlights: • LiMgPO4:Tb,B has been studied and shown to possesses minimum measurable dose (MMD) in sub micro Gray region. • MMD as low as 0.49 µGy in readout time of less than 1 s at stimulation intensity of 32 mW/cm{sup 2} has been achieved. • The OSL measurements for low doses has strengthened and validated this claim. • OSL spectrum shows several emission peaks and the prominent peak around 380 nm. - Abstract: Detection of sub micro Gray doses finds application in personnel and environmental monitoring, and nuclear forensics. Recently developed LiMgPO{sub 4}:Tb,B (LMP) is highly sensitive Optically Stimulated Luminescence (OSL) phosphor with excellent dosimetric properties. The OSL emission spectrum of LMP consists of several peaks attributed to characteristic Tb{sup 3+} emission. The OSL emission peak at 380 nm is favorable for bi-alkali PMT used in RISO reader system. It is demonstrated that significant improvement in dose detection threshold can be realized for LMP by optimization of continuous wave (CW–) OSL parameters like stimulation intensity and readout time. The minimum measurable dose (MMD) as low as 0.49 µGy in readout time of less than 1 s at stimulation intensity of 32 mW/cm{sup 2} has been achieved using this phosphor. The recommendations for choice of parameters for personnel and environmental monitoring are also discussed.

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)

TL/OSL properties of natural schist for archaeological dating and retrospective dosimetry

International Nuclear Information System (INIS)

Afouxenidis, D.; Stefanaki, E.C.; Polymeris, G.S.; Sakalis, A.; Tsirliganis, N.C.; Kitis, G.

2007-01-01

Schist, a metamorphic rock composed largely of quartz and muscovite, has been used as a building stone through the centuries in many parts of the world. In ancient Greece, it was used in buildings and monuments (Knossos, Karthaia, etc). Basic TL and OSL properties of schist are studied in the present work to evaluate its potential use in archaeological dating and retrospective dosimetry. In particular, the optical stability, as well as the linearity of the TL and OSL signal were investigated for samples of natural schist obtained from a roofing slate. The results indicate that both signals are rapidly bleached when the sample is exposed to sunlight. An exposure of 1 min reduces the TL signal by 93%, the IRSL signal by 99% and the post-IR BSL signal by 90%. The dose response was found to be linear for a radiation dose at least up to 75 Gy for the TL and the IR OSL signal and at least up to 25 Gy for the post-IR BSL signal

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

Retrospective radiation dosimetry using OSL of electronic components: Results of an inter-laboratory comparison

International Nuclear Information System (INIS)

Bassinet, C.; Woda, C.; Bortolin, E.; Della Monaca, S.; Fattibene, P.; Quattrini, M.C.; Bulanek, B.; Ekendahl, D.; Burbidge, C.I.; Cauwels, V.; Kouroukla, E.; Geber-Bergstrand, T.; Mrozik, A.; Marczewska, B.; Bilski, P.; Sholom, S.; McKeever, S.W.S.; Smith, R.W.; Veronese, I.

2014-01-01

In the framework of the EU-FP7 MULTIBIODOSE project, two protocols using OSL of resistors removed from the circuit board of mobile phones were developed with the aim to use the resistors as fortuitous dosimeters in the event of a large scale radiological accident. This paper presents the results of an inter-laboratory comparison carried out under the umbrella of EURADOS. The two aims of this exercise were the validation of the MULTIBIODOSE protocols by a large number of laboratories and the dissemination of the method with the objective of preparing the basis for a network that could increase Europe's response capacity in the case of a mass casualty radiological emergency. Twelve institutes from eleven European countries and one institute from the USA, with various degrees of expertise in OSL dosimetry, took part in the OSL inter-laboratory comparison. Generally, a good agreement within uncertainties was observed between estimated and nominal doses. - Highlights: • Resistors in mobile phones could function as reliable fortuitous dosimeters in case of a large scale radiological accident. • Two OSL protocols were validated by an inter-laboratory comparison. • It is feasible to set up a network of laboratories so as to increase the measurement capacity

Optically stimulated luminescence (OSL) and some other luminescence images from granite slices exposed with radiations

International Nuclear Information System (INIS)

Hashimoto, T.; Notoya, S.; Ojima, T.; Hoteida, M.

1995-01-01

Optically stimulated luminescence (OSL) images of some X- and γ-irradiated granite slices were obtained using photon detection through a 570 nm bandpass filter with diode-laser excitation of 910 nm. Alternative photo-induced phosphorescence (PIP) images, which were colour photographed immediately after the sunlight exposure of slice samples, were also found to be helpful in the observation of the luminescence properties and to filter selection for OSL measurements. These OSL and PIP images were compared with some other colour luminescence images, including thermoluminescence images (TLCI) and after-glow images (AGCI). It was obvious that there exists a variety of coloured emissions derived mainly from feldspar constituents and these were found to be dependent on the geological history or metamorphism of the granites. (Author)

A single-aliquot regenerative-dose method based on IR (1.49 eV) bleaching of the fast OSL component in quartz

DEFF Research Database (Denmark)

Jain, M.; Murray, A.S.; Bøtter-Jensen, L.

2005-01-01

In the optically stimulated luminescence (OSL) dating of quartz, the presence of significant medium and slow components in the initial-OSL signal (first 0.8 s or so) can give rise to erroneous dose estimates. Thus it is desirable to develop a dose estimation method that is based on the OSL from t...

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

Fiber optic based OSL set up for online and offline measurements of dose due to ionizing radiation

International Nuclear Information System (INIS)

Rawat, N.S.; Kulkarni, M.S.; Upadhyay, B.N.; Srikanth, G.; Bindra, K.S.; Oak, S.M.

2016-01-01

An optic-fiber dosimetry system based on optically stimulated luminescence (OSL) and radio-luminescence (RL) from Al_2O_3 : C single-crystal (detector) was designed and developed. The set up is intended to measure dose and dose rates at various radiological installations. The Al_2O_3:C single crystal (from Landaeur Inc. USA) was coupled to a fiber optic delivery system and OSL from the detector is stimulated via the optical fiber cable using light from a Nd:YAG laser. OSL and RL signals are later used to predict cumulative dose and dose rates using "6"0Co gamma source. (author)

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)

Attaining provenance proxies from OSL and TL sensitivities: Coupling with grain size and heavy minerals data from southern Brazilian coastal sediments

International Nuclear Information System (INIS)

Zular, André; Sawakuchi, André O.; Guedes, Carlos C.F.; Giannini, Paulo C.F.

2015-01-01

In the São Francisco do Sul (SFS) barrier in southern Brazil, the optically stimulated luminescence (OSL) and thermoluminescence (TL) sensitivities of coastal sands vary according to geomorphological units. Sands from older beach ridges (ages older than 2000 years ago) show higher OSL and TL sensitivities than younger units (ages younger than 2000 years). Geomorphological units in the SFS attest to changes in provenance as a result of a coastal climate shift evidenced through grain size and heavy mineral analysis. We argue that in the SFS barrier sands, OSL and TL sensitivity signals provide an additional proxy to climate events and can be used as an alternative method to assess changes in provenance and tracking source-to-sink systems to monitor past and future environmental changes. - Highlights: • OSL and TL sensitivities are confronted with grain size and heavy minerals data. • We report OSL and 110 °C TL sensitivities as provenance proxies. • 110 °C TL sensitivity outlines environmental changes better than OSL sensitivity data.

Periodicity of TLD badge personnel monitoring service in India

International Nuclear Information System (INIS)

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

2003-01-01

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

Study of morphological and luminescent properties (TL and OSL) of ZnO nanocrystals synthetized by coprecipitation method

Energy Technology Data Exchange (ETDEWEB)

Soares, A.F., E-mail: alvarodefarias@hotmail.com; Tatumi, S.H., E-mail: sonia.tatumi@gmail.com; Mazzo, T.M.; Rocca, R.R.; Courrol, L.C.

2017-06-15

In this work, ZnO nanocrystalline phosphorus were synthesized using the method of coprecipitation, subsequently different heat treatments at 900 and 1000 °C for 2 h and 1000 °C for 4 h were performed. Afterward, Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) emissions were verified after exposure to β-radiation. Photoluminescence results showed UV and VIS emissions. Morphological studies with X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) confirmed the crystallinity of the samples, with their well-shaped wurtzite hexagonal structures in nanoscale. ZnO calcinated at 900 °C – 2 h emitted a broad TL peak located between the 362–372 °C; for ZnO calcinated at 1000 °C – 2 h, two intense peaks were observed at 144 and 308 °C, this TL emission curve was investigated with more details using Computerized Glow Curve Deconvolution and six individual TL peaks were obtained, for sample irradiated with 40.6 Gy, corroborating with the T{sub m}-T{sub stop} results. A study of Minimum Detectable Dose (MDD) was made and a dose of (492±40) μGy was determined. CW-OSL and LM-OSL analysis were made for ZnO calcinated at 1000 °C – 2 h, allowed to verify the behaviour, and the curve existing components (fast and medium, depending on dose). As well as the calculation of the Minimum Detectable Dose for CW-OSL. - Highlights: •ZnO nanocrystals were successfully produced by the method of coprecipitation. •Grains sizes by Scherrer Equation were between 26.9–40.6 nm, corroborating with SEM. •Study of the TL emission: Computerized Glow Curve Deconvolution (CGCD) and Tm-Tstop. •TL emission of ZnO calcinated supplied the minimum detectable dose of (492±40) μGy. •Study of CW-OSL and LM-OSL with CGCD. MDD for CW-OSL evaluation of ZnO calcinated.

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

A new luminescence detection and stimulation head for the Risø TL/OSL reader

International Nuclear Information System (INIS)

Lapp, T.; Kook, M.; Murray, A.S.; Thomsen, K.J.; Buylaert, J.-P.; Jain, M.

2015-01-01

A new automated Detection And Stimulation Head (DASH) has been developed for the Risø TL/OSL luminescence reader to provide easy access to new technologies, new signals and new measurement methods. The automated DASH includes a filter changer and a detector changer that makes it possible to change stimulation filters (4 × 4 filter combinations possible) and detectors (3 detectors possible) as part of a measurements sequence. The new automated DASH with dedicated driver electronics does not affect the use of other attachments, and can be retrospectively fitted to existing Risø TL/OSL readers. - Highlights: • A new detection and stimulation head for the Risø TL/OSL reader is described. • An example of the use of the filter changer is presented. • The power and spatial uniformity of blue, green and IR stimulation are characterised. • The potential of an EMCCD camera detector is described.

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.

Optically stimulated luminescence (OSL) from Ag-doped Li{sub 2}B{sub 4}O{sub 7} crystals

Energy Technology Data Exchange (ETDEWEB)

Kananen, B.E.; Maniego, E.S.; Golden, E.M.; Giles, N.C.; McClory, J.W. [Department of Engineering Physics, Air Force Institute of Technology, Wright-Patterson Air Force Base, OH 45433 (United States); Adamiv, V.T.; Burak, Ya.V. [Vlokh Institute of Physical Optics, Dragomanov 23, L’viv 79005 (Ukraine); Halliburton, L.E., E-mail: Larry.Halliburton@mail.wvu.edu [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506 (United States)

2016-09-15

Optically stimulated luminescence (CW-OSL) is observed from Ag-doped lithium tetraborate (Li{sub 2}B{sub 4}O{sub 7}) crystals. Photoluminescence, optical absorption, and electron paramagnetic resonance (EPR) are used to identify the defects participating in the OSL process. As-grown crystals have Ag{sup +} ions substituting for Li{sup +} ions. They also have Ag{sup +} ions occupying interstitial sites. During a room-temperature exposure to ionizing radiation, holes are trapped at the Ag{sup +} ions that replace Li{sup +} ions and electrons are trapped at the interstitial Ag{sup +} ions, i.e., the radiation forms Ag{sup 2+} (4d{sup 9}) ions and Ag{sup 0} (4d{sup 10}5s{sup 1}) atoms. These Ag{sup 2+} and Ag{sup 0} centers have characteristic EPR spectra. The Ag{sup 0} centers also have a broad optical absorption band peaking near 370 nm. An OSL response is observed when the stimulation wavelength overlaps this absorption band. Specifically, stimulation with 400 nm light produces an intense OSL response when emission is monitored near 270 nm. Electrons optically released from the Ag{sup 0} centers recombine with holes trapped at Ag{sup 2+} ions to produce the ultraviolet emission. The OSL response is progressively smaller as the stimulation light is moved to longer wavelengths (i.e., away from the 370 nm peak of the absorption band of the Ag{sup 0} electron traps). Oxygen vacancies are also present in the Ag-doped Li{sub 2}B{sub 4}O{sub 7} crystals, and their role in the OSL process as a secondary relatively short-lived electron trap is described.

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

SU-E-T-592: OSL Response of Al2O3:C Detectors Exposed to Therapeutic Proton Beams

Energy Technology Data Exchange (ETDEWEB)

Granville, DA [Carleton Laboratory for Radiotherapy Physics, Carleton University, Ottawa, ON (Canada); Flint, DB; Sawakuchi, GO [The University of Texas MD Anderson Cancer Center, Houston, TX (United States)

2015-06-15

Purpose: To characterize the response of Al{sub 2}O{sub 3}:C optically stimulated luminescence (OSL) detectors (OSLDs) exposed to therapeutic proton beams of differing beam quality. Methods: We prepared Al{sub 2}O{sub 3}:C OSLDs from the same material as commercially available nanoDot dosimeters (Landauer, Inc). We irradiated the OSLDs in modulated proton beams of varying quality, as defined by the residual range. An absorbed dose to water of 0.2 Gy was delivered to all OSLDs with the residual range values varying from 0.5 to 23.5 cm (average LET in water from ∼0.5 to 2.5 keV/µm). To investigate the beam quality dependence of different emission bands within the OSL spectrum, we performed OSLD readouts using both continuous-wave stimulation (CW-OSL) and pulsed stimulation (P-OSL) with two sets of optical filters (Hoya U-340 and Kopp 5113). For all readout modes, the relative absorbed dose sensitivity (S{sub rel}) for each beam quality was calculated using OSLDs irradiated in a 6 MV photon beam as a reference. Results: We found that the relative absorbed dose sensitivity was highly dependent on both readout mode and integration time of the OSL signal. For CW-OSL signals containing only the blue emission band, S{sub rel} was between 0.85 and 0.94 for 1 s readouts and between 0.82 and 0.93 for 10 s readouts. Similarly, for P-OSL readouts containing only the blue emission band S{sub rel} ranged from 0.86 to 0.91, and 0.82 to 0.93 for 1 s and 10 s readouts, respectively. For OSLD signals containing only the UV emission band, S{sub rel} ranged from 1.00 to 1.46, and 0.97 to 1.30 for P-OSL readouts of 1 s and 10 s, respectively. Conclusion: For measurements of absorbed dose using Al{sub 2}O{sub 3}:C OSLDs in therapeutic proton beams, dependence on beam quality was smallest for readout protocols that selected the blue emission band with small integration times. DA Granville received financial support from the Natural Sciences and Engineering

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)

Application of pulsed OSL to the separation of the luminescence components from a mixed quartz/feldspar sample

International Nuclear Information System (INIS)

Denby, P.M.; Botter-Jensen, L.; Murray, A.S.; Thomsen, K.J.; Moska, P.

2006-01-01

It is known that the pulsed optically stimulated luminescence (OSL) characteristics of quartz and feldspars are very different. These differences can be used to preferentially discriminate against the feldspar signal in mixed quartz-bar feldspar mineral assemblages, or in separated quartz contaminated with a feldspar signal. We have developed instrumentation for the study of high-speed pulse stimulated OSL. Our system uses the standard blue/IR LED stimulation unit of a Riso reader (allowing stimulation pulses down to 1-2μs duration) and can thus be applied to the routine analysis of samples. Using this stimulation source, and high-speed photon timing, the OSL yield can be monitored throughout the pulsing cycle and subsequent OSL decay. It is found that the total photon yield per unit stimulation power in pulsed mode is, for quartz, twice and, for feldspar, nearly four times, that in continuous wave mode. Observation of this OSL signal, between stimulation pulses, is seen to be characteristic of the mineral being examined, and has been used to preferentially discriminate against feldspar contamination in a mixed quartz/feldspar sample. Simple implementation of this technique by gating the counting period, so that counts are only accumulated during a windowed period, reduces the feldspar signal to 1.6% of its original value relative to that of the quartz

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

Science.gov (United States)

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

2018-01-01

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

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

Does deposition depth control the OSL bleaching of fluvial sediment?

NARCIS (Netherlands)

Cunningham, A. C.; Wallinga, J.; Hobo, N.; Versendaal, A. J.; Makaske, B.; Middelkoop, H.

2014-01-01

The Optically Stimulated Luminescence (OSL) signal from fluvial sediment often contains a remnant from the previous deposition cycle, leading to a partially bleached equivalent-dose distribution. Although identification of the burial dose is of primary concern, the degree of bleaching could

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

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.

Temperature dependence of OSL decay curves: Experimental and theoretical aspects

DEFF Research Database (Denmark)

McKeever, S.W.S.; Bøtter-Jensen, L.; Agersnap Larsen, N.

1997-01-01

; (2) thermally assisted optical stimulation; (3) thermal quenching; and (4) localized donor-acceptor type recombination. Experimental OSL data from natural quartz and feldspars, stimulated with both green and infra-red light, are examined in the light of the theoretical considerations. (C) 1997...

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)

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

Correlation between TL and OSL signals in KMgF3:Ce3+: Bleaching study of individual glow-peaks

International Nuclear Information System (INIS)

Dallas, G.I.; Polymeris, G.S.; Afouxenidis, D.; Tsirliganis, N.C.; Tsagas, N.F.; Kitis, G.

2010-01-01

KMgF 3 :Ce 3+ is an ultra sensitive Thermoluminescence (TL) material with a complex TL and OSL glow-curve structure. The aim of the present work is to attempt a one-to-one correspondence between specific TL glow-peaks and OSL components in KMgF 3 :Ce 3+ . The correlation study involves the deconvolution of the TL curves and the estimation of the bleaching decay constants for individual glow-peaks followed by the deconvolution of the LM-OSL curve using the estimated decay constants. It was found that the bleaching of each individual glow-peak takes place in three different rates; namely in a fast, medium and slow rate.

Angular dependence of the nanoDot OSL dosimeter

OpenAIRE

Kerns, James R.; Kry, Stephen F.; Sahoo, Narayan; Followill, David S.; Ibbott, Geoffrey S.

2011-01-01

Purpose: Optically stimulated luminescent detectors (OSLDs) are quickly gaining popularity as passive dosimeters, with applications in medicine for linac output calibration verification, brachytherapy source verification, treatment plan quality assurance, and clinical dose measurements. With such wide applications, these dosimeters must be characterized for numerous factors affecting their response. The most abundant commercial OSLD is the InLight∕OSL system from Landauer, Inc. The purpose of...

Passive dosimetry: introduction of a new dosimeter based on OSL technology

International Nuclear Information System (INIS)

Archambault, V.; Le Roy, G.; Prugnaud, B.

2005-01-01

A new passive dosimeter based on OSL technology has been introduced on the French market. In this article are described: the technology and the material on which this new detector relied, the dosimeter itself. (author)

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

Energy Technology Data Exchange (ETDEWEB)

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

1998-12-31

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

Improvement of the M/S manipulator maintenance at OSL

International Nuclear Information System (INIS)

Kuwana, Koichi; Ouchi, Hiroshi; Ito, Yutaka; Sato, Yoshihiro; Midorikawa, Mituhiro; Hayakawa, Tuyoshi

2010-01-01

The safeguards inspection samples from the JNFL Rokkasho Reprocessing Plant (RRP) are received and analyzed at the On Site Laboratory (OSL). Since the samples from the input accountancy tank of the RRP contain a lot of fission products, they are treated in a hot-cell line with a M/S (Master /Slave) manipulator. Special equipment and tools were used for the maintenance of the M/S manipulator, especially for the exchange of the M/S manipulator. However, the manipulator exchange work was not easy due to the limitation of the space in the OSL. For solution to this problem, a monorail and monorail hoist equipment was installed onto wall surface of analytical room close to each M/S manipulator, and then it made the exchange of M/S manipulator easy without special equipment and tools. Additionally, operator was freed from the burden of working space arranging for the exchange of M/S manipulator such as removing of analytical equipments. This report represents the improvement of operation for the exchange of M/S manipulator with installation of monorail and hoist equipment. (author)

An environmental BeO-OSL dosimeter for emergency response

International Nuclear Information System (INIS)

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

2012-01-01

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

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

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

International Nuclear Information System (INIS)

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

2005-01-01

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

LM-OSL from single grains of quartz: A preliminary study

DEFF Research Database (Denmark)

Bulur, E.; Duller, G.A.T.; Solongo, S.

2002-01-01

the easy-to-bleach component, those with only the hard-to-bleach component, and those exhibiting all components. The results of this preliminary study show that LM-OSL experiments carried out at the single grain level may give important insights into the luminescence properties observed when viewing...

Characterization of an optically stimulated luminescence (OSL) material for thermal neutron detection: SrS:Ce,Sm,B

International Nuclear Information System (INIS)

Ravotti, Federico; Garcia, Pierre; Prevost, Hildegarde; Dusseau, Laurent; Lapraz, Dominique; Vaille, Jean-Roch; Benoit, David

2008-01-01

SrS:Ce,Sm exhibits some interesting phosphorescent and charge storage properties that are used in OSL (optically stimulated luminescence) radiation dosimetry. To enhance the thermal neutron sensitivity of this phosphor, a new material obtained by boron doping has been developed. This OSL, B material was analysed with respect to its optical and structural characteristics in order to study possible modifications induced by doping procedure. Optical study highlights a decrease in the material luminescence of about 40% with TL and OSL experiments. The emission spectrum remains the same after boron addition. This result is in agreement with the structural characterization analysis since the lattice parameters were not modified. 11B MAS NMR results indicate that boron atoms are present in the host lattice in form of BO4 groups. Consequences on dosimetry applications are discussed. The neutron response of the OSL, B irradiated in a nuclear reactor is linear up to a fluence of 5 x 1011 cm -2 and it is possible to separate the thermal neutron and gamma components. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Optically stimulated luminescence (OSL) dating of shallow marine sediments to develop an analysis method of late Quaternary geodynamics

International Nuclear Information System (INIS)

Hataya, Ryuta; Shirai, Masaaki

2003-01-01

To develop an analysis method of geodynamics, we have examined the applicability of the OSL dating of marine terrace deposits. We have done the OSL dating, using the multiple-aliquot additive-dose technique, of shallow marine sediments from the upper part the Kioroshi Formation in Ibaraki Prefecture, which are correlated to Marine Oxygen Isotope Stage (MIS) 5e-5c. Marine terrace deposit consists mainly of shallow marine sediment. OSL ages of foreshore and foreshore-shoreface beds are 88-112 Ka, and are in good agreement with the geological/geomorphological data. On the other hand, OSL ages of the backshore bed are younger, and ones of the shoreface bed are older than geologically estimated ages. These results show that OPSL dating method can date shallow marine sediment using samples from foreshore and foreshore-shoreface beds, and that this method can distinguish terrace deposits formed in MIS5 and that in MIS7 by taking geomorphologic information into account. These results contribute to the characterization of long-term geological movement in coastal areas. (author)

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

Thermally assisted OSL from deep traps in Al2O3:C

International Nuclear Information System (INIS)

Polymeris, G.S.; Raptis, S.; Afouxenidis, D.; Tsirliganis, N.C.; Kitis, G.

2010-01-01

The present work suggests an alternative experimental method in order to not only measure the signal of the deep traps in Al 2 O 3 :C without heating the sample to temperatures greater than 500 o C, but also use this signal for high dose level dosimetry purposes as well. This method consists of photo transfer OSL measurements performed at elevated temperatures using the blue LEDs (470 nm, FWHM 20 nm) housed at commercial Riso TL/OSL systems, after the sample was previously heated up to 500 o C in order to empty its main TL dosimetric trap. The influence of this procedure on specific features such as glow curve shape and sensitivity of the main TL glow peak was also studied.

The TL and room temperature OSL properties of the glow peak at 110 deg. C in natural milky quartz: A case study

International Nuclear Information System (INIS)

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

2009-01-01

The LM-OSL signal of quartz, while measured at room temperature, is dominated by an intermediate, broad and intense OSL component, so that its contribution and general characteristics are derived very accurately. Through a series of dose-response, bleaching and thermal decay at room temperature experiments, in conjunction with curve fitting studies, a component resolved analysis is carried out studying the correlation between this specific component, termed as LM-OSL component C 2 and the 110 deg. C TL glow peak in quartz. The dose-response of these two luminescence components behaves exactly similar being linear at low doses and saturating at almost 100 Gy. Both signals decay exponentially under illumination, providing identical optical detrapping cross-section values. Residual of both luminescence signals after thermal decay at room temperature follows an exponential law, yielding similar mean half-lives. All previous luminescence features provide strong evidence for the electron trap being the same for both the 110 deg. C TL trap and the LM-OSL component C 2 . The results of the present work are very promising and clearly support the possibility of extrapolating the TL pre-dose methodology to the OSL pre-dose effect using only the LM-OSL component C 2

Dependence of the anomalous fading of the TL and blue-OSL of fluorapatite on the occupancy of the tunnelling recombination sites

International Nuclear Information System (INIS)

Tsirliganis, N.C.; Polymeris, G.S.; Kitis, G.; Pagonis, V.

2007-01-01

The anomalous fading (AF) of thermoluminescence (TL) and optically stimulated luminescence (OSL) signals in Durango apatite is attributed to tunnelling effects. Electrons from the TL and OSL traps in this material are transferred, via a tunnelling effect, to the recombination sites. The availability of recombination sites for tunnelled electrons is of major importance for the degree of AF rate observed in this material. It is expected that a variation of the number of the electron recombination sites will be reflected in the experimentally measured AF rate. In the present work an investigation of the recombination sites for the tunnelled electrons is attempted by studying the AF effect using a special technique, in which the anomalously faded TL (OSL) is replaced by an equal amount of TL (OSL) induced by a beta dose

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)

A fiber-dosimetry method based on OSL from Al2O3:C for radiotherapy applications

International Nuclear Information System (INIS)

Gaza, R.; McKeever, S.W.S.; Akselrod, M.S.; Akselrod, A.; Underwood, T.; Yoder, C.; Andersen, C.E.; Aznar, M.C.; Marckmann, C.J.; Boetter-Jensen, L.

2004-01-01

We describe a high-sensitivity, fiber-optic dosimetry system based on optically stimulated luminescence (OSL) and radioluminescence from Al 2 O 3 :C single-crystal fibers (detectors). The detectors are coupled to a fiber optic delivery system and OSL from the detector is stimulated via the optical fiber cable using light from a Nd:YAG laser. The OSL is guided back along the same fiber and is detected by a photomultiplier tube. The Al 2 O 3 :C detectors are small and demonstrate high sensitivity with a large signal-to-noise ratio. We describe two modes of operation of the system and discuss algorithms that provide accurate estimation of dose rate and integrated dose in near real time. The system is free from magnetic and electrical interference, and is designed for use in several forms of radiotherapy, including in vitro brachytherapy source calibration, and in vivo dosimetry during patient treatment

Retrospective dosimetry using Japanese brick quartz: A way forward despite an unstable fast decaying OSL signal

DEFF Research Database (Denmark)

Fujita, Hiroki; Jain, Mayank; Murray, A.S.

2011-01-01

signals has been carried out towards identification of common source traps. It is observed that OSL from Japanese brick quartz shows unusual luminescence characteristics; in particular, the initial fast decaying OSL signal contains a dominant (>90%) thermally unstable component related to the 85 °C TL...... peak, which necessitates a prior heat treatment. A single-aliquot regenerative-dose (SAR) protocol is developed and tested using thermal treatments intended to isolate a stable dosimetric signal. A minimum detection limit of 65 mGy is then estimated using this protocol. Following irradiation using 60Co...... of Japanese brick quartz examined here can be used to derive precise estimates of accident dose, and, possibly to distinguish between sources of gamma radiation in a nuclear accident. To our knowledge, this is the first report on the existence of an unstable fast decaying OSL signal in quartz derived from...

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

Germanium-doped optical fiber for real-time radiation dosimetry

International Nuclear Information System (INIS)

Mizanur Rahman, A.K.M.; Zubair, H.T.; Begum, Mahfuza; Abdul-Rashid, H.A.; Yusoff, Z.; Ung, N.M.; Mat-Sharif, K.A.; Wan Abdullah, W.S.; Amouzad Mahdiraji, Ghafour; Amin, Y.M.; Maah, M.J.; Bradley, D.A.

2015-01-01

Over the past three decades growing demand for individualized in vivo dosimetry and subsequent dose verification has led to the pursuit of newer, novel and economically feasible materials for dosimeters. These materials are to facilitate features such as real-time sensing and fast readouts. In this paper, purposely composed SiO 2 :Ge optical fiber is presented as a suitable candidate for dosimetry. The optical fiber is meant to take advantage of the RL/OSL technique, providing both online remote monitoring of dose rate, and fast readouts for absorbed dose. A laboratory-assembled OSL reader has been used to acquire the RL/OSL response to LINAC irradiations (6 MV photons). The notable RL characteristics observed include constant level of luminescence for the same dose rate (providing better consistency compared to TLD-500), and linearity of response in the radiotherapy range (1 Gy/min to 6 Gy/min). The OSL curve was found to conform to an exponential decay characteristic (illumination with low LED source). The Ge doping resulted in an effective atomic number, Z eff , of 13.5 (within the bone equivalent range). The SiO 2 :Ge optical fiber sensor, with efficient coupling, can be a viable solution for in vivo dosimetry, besides a broad range of applications. - Highlights: • Purposely fabricated Ge doped silica fiber for real-time dose measurements. • Constant RL response for dose rates in radiotherapy range. • Linearity of RL curve during irradiation using LINAC. • RL response comparison between SiO 2 :Ge optical fiber and TLD-500.

Optimization of CW-OSL parameters for improved dose detection threshold in Al2O3:C

International Nuclear Information System (INIS)

Rawat, N.S.; Dhabekar, B.; Kulkarni, M.S.; Muthe, K.P.; Mishra, D.R.; Soni, A.; Gupta, S.K.; Babu, D.A.R.

2014-01-01

Continuous wave optically stimulated luminescence (CW-OSL) is relatively a simple technique that offers good signal to noise ratio (SNR) and involves simple instrumentation. This study reports the influence and optimization of CW-OSL parameters on minimum detectable dose (MDD) using α-Al 2 O 3 :C phosphor. It is found that at a given stimulation intensity MDD in CW-OSL mode depends on signal integration time. At lower integration times MDD is inferior. It exhibits an improvement for intermediate values, shows a plateau region and deteriorates as integration time increases further. MDD is found to be ∼127 μGy at 4 mW/cm 2 stimulation intensity for integration time of 0.1 s, which improves to ∼10.5 μGy for 60 s. At stimulation intensity of 72 mW/cm 2 , MDD is 37 μGy for integration time of 60 s and improves significantly to 7 μGy for 1 s. - Highlights: • CW-OSL parameters are optimized to obtain best SNR and MDD in Al 2 O 3 :C. • MDD is found to depend on signal integration time and stimulation intensity. • With time, MDD initially improves, stabilizes then deteriorates. • At a given intensity, MDD is optimum for a certain range of integration time

On the use of OSL of wire-bond chip card modules for retrospective and accident dosimetry

Energy Technology Data Exchange (ETDEWEB)

Woda, Clemens [Helmholtz Zentrum Muenchen - German Research Centre for Environmental Health, Institute of Radiation Protection, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany)], E-mail: clemens.woda@helmholtz-muenchen.de; Spoettl, Thomas [Infineon Technologies AG, Wernerwerkstrasse 1, D-93049 Regensburg (Germany)

2009-05-15

The potential of optically stimulated luminescence of wire-bond chip card modules, used in health insurance, ID, cash and credit cards for retrospective and accident dosimetry is investigated. Chip card modules obtained directly from the producer, using a widely spread UV-cured epoxy product for encapsulation, are used as basis for the study. The radiation sensitivity is due to silica grains added to the epoxy for controlling the thixotropic properties. Luminescence properties are complex due to the presumed thermo-optical release of electrons from the epoxy and transfer into the silica. Best results and highest sensitivity are obtained by using no or only low preheat treatments. A high degree of fading of the OSL signal during storage at room temperature is observed, which is tentatively explained by the superposition of thermal decay of shallow OSL traps and athermal (anomalous) decay of deeper OSL traps. The dose response of the OSL signal shows exponentially saturating behaviour, with saturation doses of 77 Gy or 9.6 Gy, depending on pretreatment. Dose recovery tests show that given doses can be recovered within a deviation of {+-}14%, if measured signals are corrected for fading. The minimum detectable dose is estimated at {approx}3 mGy, {approx}10 mGy and {approx}20 mGy for readouts immediately, 1 day and 10 days after exposure, respectively.

On the use of OSL of wire-bond chip card modules for retrospective and accident dosimetry

International Nuclear Information System (INIS)

Woda, Clemens; Spoettl, Thomas

2009-01-01

The potential of optically stimulated luminescence of wire-bond chip card modules, used in health insurance, ID, cash and credit cards for retrospective and accident dosimetry is investigated. Chip card modules obtained directly from the producer, using a widely spread UV-cured epoxy product for encapsulation, are used as basis for the study. The radiation sensitivity is due to silica grains added to the epoxy for controlling the thixotropic properties. Luminescence properties are complex due to the presumed thermo-optical release of electrons from the epoxy and transfer into the silica. Best results and highest sensitivity are obtained by using no or only low preheat treatments. A high degree of fading of the OSL signal during storage at room temperature is observed, which is tentatively explained by the superposition of thermal decay of shallow OSL traps and athermal (anomalous) decay of deeper OSL traps. The dose response of the OSL signal shows exponentially saturating behaviour, with saturation doses of 77 Gy or 9.6 Gy, depending on pretreatment. Dose recovery tests show that given doses can be recovered within a deviation of ±14%, if measured signals are corrected for fading. The minimum detectable dose is estimated at ∼3 mGy, ∼10 mGy and ∼20 mGy for readouts immediately, 1 day and 10 days after exposure, respectively.

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

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

An application of artificial neural intelligence for personal dose assessment using a multi-area OSL dosimetry system

International Nuclear Information System (INIS)

Lee, S.-Y.Sang-Yoon.; Kim, B.-H.Bong-Hwan; Lee, K.J.Kun Jai

2001-01-01

Significant advances have been made in recent years to improve measurement technology and performance of phosphor materials in the fields of optically stimulated luminescence (OSL) dosimetry. Pulsed and continuous wave OSL studies recently carried out on α-Al 2 O 3 : C have shown that the material seems to be the most promising for routine application of OSL for dosimetric purposes. The main objective of the study is to propose a new personal dosimetry system using α-Al 2 O 3 : C by taking advantage of its optical properties and energy dependencies. In the process of the study, a new dose assessment algorithm was developed using artificial neural networks in hopes of achieving a higher degree of accuracy and precision in personal OSL dosimetry system. The original hypothesis of this work is that the spectral information of an X- and γ-ray fields may be obtained by the analysis of the response of a multi-element system. In this study, a feedforward neural network using the error back-propagation method with Bayesian optimization was applied for the response unfolding procedure. The validation of the proposed algorithm was investigated by unfolding the 10 measured responses of α-Al 2 O 3 : C for arbitrarily mixed photon fields which range from 20 to 662 keV

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.

TL and OSL properties of Mn2+-doped MgGa2O4 phosphor

Science.gov (United States)

Luchechko, A.; Zhydachevskyy, Ya; Maraba, D.; Bulur, E.; Ubizskii, S.; Kravets, O.

2018-04-01

The oxide MgGa2O4 spinel ceramics doped with Mn2+ ions was synthesized by a solid-state reaction at 1200 °C in air. The activator concentration was equal 0.05 mol% of MnO. Phase purity of the synthesized samples was analyzed by X-ray diffraction technique. This spinel ceramics show efficient green emission in the range from 470 to 550 nm with a maximum at about 505 nm under UV or X-ray excitations, which is due to Mn2+ ions. MgGa2O4: Mn2+ exhibits intense thermoluminescence (TL) and optically stimulated luminescence (OSL) after influence of ionizing radiation. Are complex nature of the TL glow curves is associated with a significant number of structural defects that are responsible for the formation of shallow and deep electron traps. In this work, time-resolved OSL characteristics of the samples exposed to beta particles are reported for the first time. A light from green LED was used for optical stimulation. Obtained TL and OSL results suggest MgGa2O4:Mn2+ as perspective material for further research and possible application in radiation dosimetry.

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

Analysis of optical bleaching of OSL signal in sediment quartz

International Nuclear Information System (INIS)

Przegiętka, K.R.; Chruścińska, A.

2013-01-01

The aim of this work was to study the effect of the quality of optical bleaching on the results of OSL (Optically Stimulated Luminescence) dating method. The large aliquots of coarse quartz grains extracted from fluvial deposit were used in the study. The poor, medium and good bleaching were simulated in laboratory with help of Blue LED light source in series of experiments. Then the samples were irradiated with a common laboratory dose. The equivalent doses (DE) were measured by the help of standard Single Aliquot Regeneration (SAR) technique, but obtained DE distributions are analyzed in a new way. The method for recognizing and compensating for partial bleaching is proposed. The conclusions for dating sediment quartz samples are presented and discussed. -- Highlights: ► Bleaching experiments on sediment quartz are performed. ► Blue LED light source incorporated in luminescence reader is used. ► New analysis of data measured by standard SAR OSL technique is proposed. ► The results are promising for recognizing and compensating for partial bleaching

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

Quartz OSL Dating of the loess deposit in the eastern Tibetan Plateau and its environment implications since the Last Glaciation

Science.gov (United States)

Yang, S.; Cheng, T.; Liu, W.; Fang, X.

2017-12-01

Loess deposit is widespread in the Chuanxi Plateau, the eastern Tibetan Plateau, which is a critical archive for understanding the aeolian process, the evolution of the westerly and the environment changes on the Plateau. Previous studies have shown its aeolian origin, and mainly transported by wind from the western part of the Tibetan Plateau. However, the aeolian processes of the loess and its environment implications are not well understood mainly due to lack of detailed age controls. We carry out a combined quartz optically stimulated luminescence (OSL) dating and accelerator mass spectrometry radiocarbon dating (AMS 14-C) for the loess deposits in Garzê and Jinchuan. The results indicate that the quartz OSL dating can provide reliable age controls for the loess-paleosol sequences from the Chuanxi Plateau, showing the potential of OSL to date loess in the high altitude region. The results indicate that the OSL ages are in agreement with the observed stratigraphy in the field. The constructed OSL and AMS 14-C chronology of the Garzê loess reveals that the widespread loess in Ganzi Region deposited since the Last Glacial. The dust accumulation is rapid during marine isotope stage (MIS) 3 and 2, and a relative low accumulation rate in the Holocene, which may related with the desertification processes of the inner Tibetan Plateau.

Optically stimulated luminescence (OSL) as a chronometer for surface exposure dating

DEFF Research Database (Denmark)

Sohbati, Reza; Murray, Andrew S.; Chapot, Melissa S.

2012-01-01

We pioneer a technique of surface-exposure dating based upon the characteristic form of an optically stimulated luminescence (OSL) bleaching profile beneath a rock surface; this evolves as a function of depth and time. As a field illustration of this new method, the maximum age of a premier example...... exposure histories; one of these samples was exposed at the time of sampling and one was buried and no longer light exposed. A third sample is known to have been first exposed 80 years ago and was still exposed at the time of sampling. First, the OSL-depth profile of the known-age sample is modeled...... to estimate material-dependent and environmental parameters. These parameters are then used to fit the model to the corresponding data for the samples of unknown exposure history. From these fits we calculate that the buried sample was light exposed for similar to 700 years before burial and that the unburied...

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)

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)

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

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

Science.gov (United States)

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

2014-05-01

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

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)

Single-grain quartz OSL dating of debris flow deposits from Men Tou Gou, south west Beijing, China

DEFF Research Database (Denmark)

Zhao, Qiuyue; Thomsen, Kristina Jørkov; Murray, A. S.

2017-01-01

of the return frequency of these debris flows, risk assessment and climate change research. In this project, we use quartz single-grain optically stimulated luminescence (OSL) methods to determine the burial ages of five debris flow samples from the Zhai Tang region -60 km west of Beijing. OSL characteristics...... poorly bleached prior to deposition; relative over-dispersions are larger than 60%. Minimum age modelling indicates that all five samples were deposited within the past few hundred years, indicating that catastrophic debris flows are occurring under the historically-recent land-use pattern....

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)

Mortar and surface dating with Optically Stimulated Luminescence (OSL): Innovative techniques for the age determination of buildings

International Nuclear Information System (INIS)

Panzeri, L.

2013-01-01

In this work the results of a dating study on bricks and mortars using both Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) are shown. The samples came from the outside walls of the Certosa di Pavia, located in northern Italy and independently dated (XVII-XVIII century). TL dating, applied to bricks using the fine grain technique, allowed to determine the time of manufacture of the bricks (XII century), that resulted therefore re-used. To circumvent this problem the application of two innovative dating techniques, OSL surface dating and mortar dating, was attempted. The first was applied to the light-shielded surfaces of bricks and allowed to successfully determine the edification of the wall (XVII century). Mortar dating gave instead severe age overestimation: the results obtained on coarse grain quartz with the SAR technique both on multi-grains aliquots and with single-grain analyses were highly dispersed indicating an incomplete bleaching of the quartz grains. The shine-down curves were in fact characterized by the absence of the so-called fast component, as confirmed by Linear Modulated OSL technique.

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)

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

International Nuclear Information System (INIS)

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

1997-01-01

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

A method to acquire CT organ dose map using OSL dosimeters and ATOM anthropomorphic phantoms

Energy Technology Data Exchange (ETDEWEB)

Zhang, Da; Li, Xinhua; Liu, Bob [Division of Diagnostic Imaging Physics and Webster Center for Advanced Research and Education in Radiation, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States); Gao, Yiming; Xu, X. George [Nuclear Engineering Program, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

2013-08-15

Purpose: To present the design and procedure of an experimental method for acquiring densely sampled organ dose map for CT applications, based on optically stimulated luminescence (OSL) dosimeters “nanoDots” and standard ATOM anthropomorphic phantoms; and to provide the results of applying the method—a dose data set with good statistics for the comparison with Monte Carlo simulation result in the future.Methods: A standard ATOM phantom has densely located holes (in 3 × 3 cm or 1.5 × 1.5 cm grids), which are too small (5 mm in diameter) to host many types of dosimeters, including the nanoDots. The authors modified the conventional way in which nanoDots are used, by removing the OSL disks from the holders before inserting them inside a standard ATOM phantom for dose measurements. The authors solved three technical difficulties introduced by this modification: (1) energy dependent dose calibration for raw OSL readings; (2) influence of the brief background exposure of OSL disks to dimmed room light; (3) correct pairing between the dose readings and measurement locations. The authors acquired 100 dose measurements at various positions in the phantom, which was scanned using a clinical chest protocol with both angular and z-axis tube current modulations.Results: Dose calibration was performed according to the beam qualities inside the phantom as determined from an established Monte Carlo model of the scanner. The influence of the brief exposure to dimmed room light was evaluated and deemed negligible. Pairing between the OSL readings and measurement locations was ensured by the experimental design. The organ doses measured for a routine adult chest scan protocol ranged from 9.4 to 18.8 mGy, depending on the composition, location, and surrounding anatomy of the organs. The dose distribution across different slices of the phantom strongly depended on the z-axis mA modulation. In the same slice, doses to the soft tissues other than the spinal cord demonstrated

A method to acquire CT organ dose map using OSL dosimeters and ATOM anthropomorphic phantoms

International Nuclear Information System (INIS)

Zhang, Da; Li, Xinhua; Liu, Bob; Gao, Yiming; Xu, X. George

2013-01-01

Purpose: To present the design and procedure of an experimental method for acquiring densely sampled organ dose map for CT applications, based on optically stimulated luminescence (OSL) dosimeters “nanoDots” and standard ATOM anthropomorphic phantoms; and to provide the results of applying the method—a dose data set with good statistics for the comparison with Monte Carlo simulation result in the future.Methods: A standard ATOM phantom has densely located holes (in 3 × 3 cm or 1.5 × 1.5 cm grids), which are too small (5 mm in diameter) to host many types of dosimeters, including the nanoDots. The authors modified the conventional way in which nanoDots are used, by removing the OSL disks from the holders before inserting them inside a standard ATOM phantom for dose measurements. The authors solved three technical difficulties introduced by this modification: (1) energy dependent dose calibration for raw OSL readings; (2) influence of the brief background exposure of OSL disks to dimmed room light; (3) correct pairing between the dose readings and measurement locations. The authors acquired 100 dose measurements at various positions in the phantom, which was scanned using a clinical chest protocol with both angular and z-axis tube current modulations.Results: Dose calibration was performed according to the beam qualities inside the phantom as determined from an established Monte Carlo model of the scanner. The influence of the brief exposure to dimmed room light was evaluated and deemed negligible. Pairing between the OSL readings and measurement locations was ensured by the experimental design. The organ doses measured for a routine adult chest scan protocol ranged from 9.4 to 18.8 mGy, depending on the composition, location, and surrounding anatomy of the organs. The dose distribution across different slices of the phantom strongly depended on the z-axis mA modulation. In the same slice, doses to the soft tissues other than the spinal cord demonstrated

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)

Two-dimensional chronostratigraphic modelling of OSL ages from recent beach-ridge deposits, SE Australia

DEFF Research Database (Denmark)

Tamura, Toru; Cunningham, Alastair C.; Oliver, Thomas S.N.

2018-01-01

Optically-stimulated luminesecne (OSL) dating, in concert with two-dimensional ground-penetrating radar (GPR) profiling, has contributed to significant advances in our understanding of beach-ridge systems and other sedimentary landforms in various settings. For recent beach-ridges, the good OSL...... samples may be larger than the difference in sample ages. Age inversions can be avoided, however, if the stratigraphic constraints are included in the age estimation process. Here, we create a custom Bayesian chronological model for a recent (..., for direct comparison with a GPR profile. The model includes a full ‘burial-dose model’ for each sample and a dose rate term with the modelled ages constrained by the vertical and shore-normal sample order. The modelled ages are visualized by plotting isochrones on the beach-ridge cross section...

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

Constraining Middle Pleistocene Glaciations in Birmingham, England; Using Optical Stimulated Luminescence (OSL) Dating.

Science.gov (United States)

Gibson, S. M.; Gibbard, P. L.; Bateman, M. D.; Boreham, S.

2014-12-01

Birmingham is built on a complex sequence of Middle Pleistocene sediments, representing at least three lowland glaciations (MIS12, MIS6, and MIS2). British Geological Survey mapping accounts 75% of the land mass as Quaternary deposits; predominantly glacial-sandy tills, glacial-fluvial sands, clays and organic silts and peats. Understanding the age of fluvial-glacial outwash, related to specific glaciations, is critical in establishing a Geochronology of Birmingham. Shotton (1953) found a series of Middle Pleistocene glacial sediments, termed the Wolstonian, intermediate in age between MIS11 and MIS5e Interglacial's. Uncertainty surrounding the relation to East Anglian sequences developed by Rose (1987) implies Birmingham sequences should be referred to MIS12. Despite this, younger Middle Pleistocene glacial sequences occur in Birmingham, yet uncertainty has deepened over our understanding of the complex, inaccessible sediments, especially as deposits have similar extent with MIS2 sequences. Five Optical Stimulated Luminescence (OSL) dates from three sites around Birmingham have been sampled. East of Birmingham, ice advanced from the Irish Sea and later the North East. In Wolston, a sample of outwash sand, associated with the Thurssington Till, is dated. In Meriden, two samples of outwash sands, associated with a distal Oadby Till, are dated. West of Birmingham, ice advanced from the Welsh Ice Sheet. In Seisdon, two samples of an Esker and outwash sand, associated with a Ridgeacre Till, are dated. Correlation of OSL dates provide an important constraint on understanding the history of Birmingham. Using GSI3D modeling to correlate geochronology and sedimentology, the significance of OSL dating can be understood within the complex sequences (and regional stratigraphy), complimented by Cosmogenic and Palynology dates taken in South West and North East. OSL dating on Birmingham's outwash sands, deposited by extensive repeated Middle Pleistocene glaciations, asserts the

Production of LiF films for dosimetric thermoluminescence application; Producao de filmes de LiF para aplicacao em dosimetria termoluminescente

Energy Technology Data Exchange (ETDEWEB)

Mauricio, Claudia Lucia de Pinho

2000-12-01

This work studies the LiF monolayer and multilayer polycrystalline film's dosimetric properties. The films were produced by electron beam evaporation technique in aluminium and stainless steel substrates maintained at several temperatures. As dosimetric variable, the intensity of the thermoluminescent (TL) glow curve of the films was used. effects of the substrate type and temperature; of the addition of layers of Mg F{sub 2} NaF and Cu F{sub 2} to the LiF films; and of thermal treatments in the TL response of the produced films were studied. The microstructural characterization of the films was accomplished through measures of scanning electronic microscopy and grazing incidence X-rays diffraction analysis. The dosimetric characterization was made of gamma radiation exposure in a {sup 60} Co source, with kerma from 0,1 to 500 Gy. Studies of reproducibility, homogeneity, stability and other environmental effects were also made. LiF and Cu F{sub 2}: LiF; Mg F{sub 2} films were the only ones that presented mechanical stability and reproducibility of the TL emission. There is a strong indication of some correlation between the residual tension fields inside the films and the intensity of its TL emission peaks. LiF monolayer films present supralinear behaviour from 0,2 to 100 Gy. These films present a main TL glow peak around 150 deg C, whose half-time is about 30 days. Its volumetric sensitivity can reach about 60 times that of LiF powder and about 0,25 that of TLD100 (LiF:Mg, Ti commercial dosimeter from Harshaw Chemical Co.) The homogeneity and reproducibility inside a same film batch is better than 12% for 95% confidence level. Cu F{sub 2} : LiF: Mg F{sub 2} films present linear behaviour from 3 to 500 Gy and its main TL glow peak around 200 deg C did not present any fading for a a period of 30 days, in laboratory conditions. This glow peak is characteristic of the Mg doping of LiF, which confirms the diffusion of Mg ions from the Mg F{sub 2} layer to the Li

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

Estimation of identification limit for a small-type OSL dosimeter on the medical images by measurement of X-ray spectra.

Science.gov (United States)

Takegami, Kazuki; Hayashi, Hiroaki; Okino, Hiroki; Kimoto, Natsumi; Maehata, Itsumi; Kanazawa, Yuki; Okazaki, Tohru; Hashizume, Takuya; Kobayashi, Ikuo

2016-07-01

Our aim in this study is to derive an identification limit on a dosimeter for not disturbing a medical image when patients wear a small-type optically stimulated luminescence (OSL) dosimeter on their bodies during X-ray diagnostic imaging. For evaluation of the detection limit based on an analysis of X-ray spectra, we propose a new quantitative identification method. We performed experiments for which we used diagnostic X-ray equipment, a soft-tissue-equivalent phantom (1-20 cm), and a CdTe X-ray spectrometer assuming one pixel of the X-ray imaging detector. Then, with the following two experimental settings, corresponding X-ray spectra were measured with 40-120 kVp and 0.5-1000 mAs at a source-to-detector distance of 100 cm: (1) X-rays penetrating a soft-tissue-equivalent phantom with the OSL dosimeter attached directly on the phantom, and (2) X-rays penetrating only the soft-tissue-equivalent phantom. Next, the energy fluence and errors in the fluence were calculated from the spectra. When the energy fluence with errors concerning these two experimental conditions was estimated to be indistinctive, we defined the condition as the OSL dosimeter not being identified on the X-ray image. Based on our analysis, we determined the identification limit of the dosimeter. We then compared our results with those for the general irradiation conditions used in clinics. We found that the OSL dosimeter could not be identified under the irradiation conditions of abdominal and chest radiography, namely, one can apply the OSL dosimeter to measurement of the exposure dose in the irradiation field of X-rays without disturbing medical images.

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

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)

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

Online fibre optic OSL in vivo dosimetry for quality assurance of external beam radiation therapy treatments: The ANR-TECSAN Codofer Project

International Nuclear Information System (INIS)

Magne, S.; Ferdinand, P.; De Carlan, L.; Bridier, A.; Isambert, A.; Hugon, R.; Guillon, J.

2010-01-01

The Codofer Project (2007-2009), led under the ANR-TECSAN Call, was coordinated by CEA LIST, in partnership with IGR and the Fimel company. The aim of the project was to design and test both metrologically and in clinical conditions OSL optical fiber sensors dedicated to in vivo dosimetry during external beam radiation therapy treatment with high-energy electrons. This study, combined with the results of clinical tests obtained within the European Project Maestro, has demonstrated the advantages of OSL/FO dosimetry for providing quality assurance of treatments. However, the French market for dosimetry has greatly changed as a result of the rules decreed by the French government in 2007. The OSL/FO product is now targeted for other treatment modalities lacking suitable dosimeters (ANR-INTRADOSE Project [2009-2011]). (authors)

Quartz OSL dating of late Holocene beach ridges from the Magdalen Islands (Quebec, Canada)

DEFF Research Database (Denmark)

Remillard, A.M.; Buylaert, Jan-Pieter; Murray, Andrew

2015-01-01

Quartz optically stimulated luminescence (OSL) dating has been applied to sandy beach ridge systems from the Magdalen Islands in the center of the Gulf of St. Lawrence (Quebec, Canada) to provide the first chronological framework for these features. Nineteen beach ridges (22 samples) from four......). The OSL ages indicate that the ridges were built between 2.6 ± 0.2 ka and 0.40 ± 0.10 ka, i.e. during a period of sea level rise. This rise eroded adjacent sandstone cliffs, which contributed a significant sediment supply to the littoral drift and beaches. Some low-lying coasts in the archipelago...... great potential in this area, and is an appropriate method for establishing precise chronologies for coastal sediments in this region of the Gulf of St. Lawrence. © 2015 Elsevier B.V. All rights reserved....

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.

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

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)

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)

TL/OSL ages from Salto Formation (Uruguay)tectonic, climatic and environmental considerations

International Nuclear Information System (INIS)

Ubilla, M.; Veroslavsky, G.

2004-01-01

TL/OSL ages from Salto Formation based on two sandy samples collected at Salto City and Route 3 (Boycua Creek) are provided: 986±100 ky (LVD-948) and 830±95 ky (LVD-949) respectively. Both support a Pleistocene age for Salto Formation, approximately late early/early middle Pleistocene. Neotectonic and climatic processes are also discussed [es

OSL sensitivity changes during single aliquot procedures: Computer simulations

DEFF Research Database (Denmark)

McKeever, S.W.S.; Agersnap Larsen, N.; Bøtter-Jensen, L.

1997-01-01

We present computer simulations of sensitivity changes obtained during single aliquot, regeneration procedures. The simulations indicate that the sensitivity changes are the combined result of shallow trap and deep trap effects. Four separate processes have been identified. Although procedures can...... be suggested to eliminate the shallow trap effects, it appears that the deep trap effects cannot be removed. The character of the sensitivity changes which result from these effects is seen to be dependent upon several external parameters, including the extent of bleaching of the OSL signal, the laboratory...

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.

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)

Production of LiF films for dosimetric thermoluminescence application

International Nuclear Information System (INIS)

Mauricio, Claudia Lucia de Pinho

2000-12-01

This work studies the LiF monolayer and multilayer polycrystalline film's dosimetric properties. The films were produced by electron beam evaporation technique in aluminium and stainless steel substrates maintained at several temperatures. As dosimetric variable, the intensity of the thermoluminescent (TL) glow curve of the films was used. effects of the substrate type and temperature; of the addition of layers of Mg F 2 NaF and Cu F 2 to the LiF films; and of thermal treatments in the TL response of the produced films were studied. The microstructural characterization of the films was accomplished through measures of scanning electronic microscopy and grazing incidence X-rays diffraction analysis. The dosimetric characterization was made of gamma radiation exposure in a 60 Co source, with kerma from 0,1 to 500 Gy. Studies of reproducibility, homogeneity, stability and other environmental effects were also made. LiF and Cu F 2 : LiF; Mg F 2 films were the only ones that presented mechanical stability and reproducibility of the TL emission. There is a strong indication of some correlation between the residual tension fields inside the films and the intensity of its TL emission peaks. LiF monolayer films present supralinear behaviour from 0,2 to 100 Gy. These films present a main TL glow peak around 150 deg C, whose half-time is about 30 days. Its volumetric sensitivity can reach about 60 times that of LiF powder and about 0,25 that of TLD100 (LiF:Mg, Ti commercial dosimeter from Harshaw Chemical Co.) The homogeneity and reproducibility inside a same film batch is better than 12% for 95% confidence level. Cu F 2 : LiF: Mg F 2 films present linear behaviour from 3 to 500 Gy and its main TL glow peak around 200 deg C did not present any fading for a a period of 30 days, in laboratory conditions. This glow peak is characteristic of the Mg doping of LiF, which confirms the diffusion of Mg ions from the Mg F 2 layer to the LiF layer. The TL volumetric sensitivity of these

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

A luminescence imaging system for the routine measurement of single-grain OSL dose distributions

DEFF Research Database (Denmark)

Kook, Myung Ho; Lapp, Torben; Murray, Andrew

2015-01-01

the potential of an electron multiplying charge-coupled device (EMCCD), providing extremely low level light detection. We characterize the performance of the device by discussing reproducibility and evaluating uncertainties in OSL signals. Finally we derive a typical single grain natural dose distribution...

Dose evaluation using multiple-aliquot quartz OSL: Test of methods and a new protocol for improved accuracy and precision

DEFF Research Database (Denmark)

Jain, M.; Bøtter-Jensen, L.; Singhvi, A.K.

2003-01-01

-dose-dependent sensitivity changes during the pre-heat, and fundamental variability in the shapes of quartz OSL (blue-green or blue-light stimulated luminescence) decay forms. A new protocol using a combination of 'elevated temperature IR cleaning' (ETIR) and 'component-specific dose normalisation' (CSDN) has been developed....... CSDN accounts for variability in the OSL decay forms and absorbs such sensitivity changes. A combination of ETIR and CSDN protocol increased palaeodose precision from +/-100% to +/-4% in quartz separates from the fluvially transported sands in the Thar desert. A comparison with palaeodose estimates...

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

International Nuclear Information System (INIS)

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

2012-01-01

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

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)

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

High-resolution OSL chronology of a sediment core from Lake Nam Co on the southern Tibetan Plateau: Comparison with radiocarbon dating

Science.gov (United States)

Long, Hao; Shen, Ji; Haberzettl, Torsten; Fuchs, Markus; Frechen, Manfred; Wang, Junbo

2013-04-01

Numerous studies on lake sediment cores from the Tibetan Plateau aimed to reconstruct spatial and temporal changes of the late Glacial and Holocene monsoon variations, which are characterized by fluctuations in precipitation and expansion of monsoonal air masses across the Plateau. Accurate and reliable dating of lacustrine deposits is of crucial importance in both the reconstruction of palaeolake and palaeoclimate evolution and the understanding of the mechanisms for climate changes, especially abrupt changes of regional-hemispheric hydrological circulation. Radiocarbon dating is the most commonly used method for establishing chronologies of lake sediments. However, 14C dating of such sediments could be problematic due to the lack of organic matter or a reservoir effect, which appears common in radiocarbon dating of lacustrine sediments from the Tibetan Plateau. In this study, ca. 10.5 m long core (NC core) was retrieved from the water depth of 93 m at Nam Co Lake, which is the second largest saline lake in China, located on the southern Tibetan Plateau. For this core, high-resolution samples (23 samples) were obtained for optically stimulated luminescence (OSL) dating. Quartz of fine-grain (4-11 μm) fraction were extracted from this samples for OSL dating, which is compared with the 14C chronology of NC core based on accelerator mass spectrometry (AMS) dating of bulk organic matter of 22 samples. The sample from the top of NC core was dated to approximate zero age, indicating the sediments bleached well before deposition. Luminescence behaviors of the study samples further confirmed the robustness of OSL ages. Comparison between OSL and 14C ages suggested that: (1) two kinds of ages are in agreement within error from top to 1.8 m, (2) from 1.8 m to the base of NC core, the 14C ages show a general trend to ca. 4 ka higher ages than the OSL ages. Although 14C dating overestimate the ages from 1.8 m to base, they still show the general trend in sedimentation rate

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

Energy Technology Data Exchange (ETDEWEB)

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

2012-05-15

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

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

International Nuclear Information System (INIS)

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

2012-01-01

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

Real time dose rate measurements with fiber optic probes based on the RL and OSL of beryllium oxide

International Nuclear Information System (INIS)

Teichmann, T.; Sponner, J.; Jakobi, Ch.; Henniger, J.

2016-01-01

This work covers the examination of fiber optical probes based on the radioluminescence and real time optically stimulated luminescence of beryllium oxide. Experiments are carried out to determine the fundamental dosimetric and temporal properties of the system and evaluate its suitability for dose rate measurements in brachytherapy and other applications using non-pulsed radiation fields. For this purpose the responses of the radioluminescence and optically stimulated luminescence signal have been investigated in the dose rate range of 20 mGy/h to 3.6 Gy/h and for doses of 1 mGy up to 6 Gy. Furthermore, a new, efficient analysis procedure, the double phase reference summing, is introduced, leading to a real time optically stimulated luminescence signal. This method allows a complete compensation of the stem effect during the measurement. In contrast to previous works, the stimulation of the 1 mm cylindrical beryllium oxide detectors is performed with a symmetric function during irradiation. The investigated dose rates range from 0.3 to 3.6 Gy/h. The real time optically stimulated luminescence signal of beryllium oxide shows a dependency on both the dose rate and the applied dose. To overcome the problem of dose dependency, further experiments using higher stimulation intensities have to follow. - Highlights: • RL and OSL measurements with BeO extended to low dose (rate) range. • A new method to obtain the real time OSL: Dual Phase Reference Summing. • Real time OSL signal shows both dose and dose rate dependency. • Real time OSL enables a complete discrimination of the stem effect.

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

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

International Nuclear Information System (INIS)

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

1999-01-01

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

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)

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

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)

TL, OSL and C-14 dating results of the sediments and bricks from mummified nuns' grave

Directory of Open Access Journals (Sweden)

Diego R.G. Tudela

2012-06-01

Full Text Available This paper presents the results of TL and OSL dating of soil and fragments of bricks from a grave, which was occupied by two mummified nuns, found at "Luz" Monastery, located in the state of São Paulo, Brazil. The TL and OSL ages were compared to C-14 dating ones obtained from bone collagens of the mummies. The majority of the ages is related to the eighteenth century. The gamma-ray spectroscopy was used to evaluate natural radioisotope concentrations in the samples, and by using these concentrations the annual dose rates, from 3.0 to 5.3 Gy/kyr, were obtained. Neutron activation analysis was performed and the radioisotope contents results are in agreement with those obtained by gamma-ray spectroscopy. The contents of U, Th and Ce elements were higher than those found in usual sediments.Este artigo apresenta os resultados de datação por TL e OSL de solos, e fragmentos de tijolos de um túmulo, que foi ocupado por duas freiras mumificadas encontradas no Mosteiro da "Luz", localizado no Estado de São Paulo, Brasil. As idades encontradas por TL e OSL foram comparadas às obtidas a partir de C-14 dos colágenos contidos em amostras de osso das múmias. A maioria das idades obtidas são do século XVIII. A espectroscopia de radiação-gama foi utilizada para avaliar concentrações de radioisótopos naturais nas amostras e para calcular as taxas de dose anual que resultaram em 3,0 a 5,3 Gy/kano. As concentrações radioativas são próximas daquelas obtidas através de Análise por Ativação de Nêutrons. Os conteúdos de elementos U, Th e Ce são superiores aos encontrados na maioria dos sedimentos.

Resetting of Quartz OSL (optically stimulated luminescence) Signals by Frictional Heating in Experimentally Sheared Gouges at Seismic Slip Rates.

Science.gov (United States)

Kim, J. H.; Choi, J. H.; Chauhan, N.; Lee, S.; Hirose, T.; Ree, J. H.

2014-12-01

Recent studies on natural and experimental seismic faults have revealed that frictional heating plays an important role in earthquake dynamics as well as in producing mineralogical and microstructural signatures of seismic faulting. Here, we report changes in OSL signals in quartz by frictional heating in experimental fault gouges. The gouges (80% of quartz and 20% of bentonite by weight) with a thickness of 1 mm were sheared between sandstone cylinders (diameter: 25 mm) at a normal stress of 1 MPa and slip rate of 1.31 m/s. The quartz grains from a sand dune on the western coast of South Korea were sieved to select size fractions between 90 and 250 μm. The equivalent dose (De) of the undeformed quartz grains was 8.0 ± 0.3 Gy. Upon displacement, the friction abruptly increases to the 1st peak (with friction coefficient μ ≈ 0.75) followed by slip weakening. Then the fault zones show two more peak frictions (μ ≈ 0.53~0.75) and finally reach a steady-state friction (μ ≈ 0.2~0.35). The fault can be divided into three zones based grain size (thus slip rate); slip localization (SLZ), intermediate slip-rate (ISZ) and low slip-rate (LSZ) zones. SLZ develops adjacent to the moving side of the sandstone cylinder with P-foliation and shear band. The size of quartz (Dq) in ISZ and LSZ is 5-30 μm and 50-250 μm, respectively. SEM and TEM analyses indicate that the fault gouge of SLZ consists of subangular quartz clasts (Dq ≈ 3 μm) and matrix of nano-scale quartz, unidentified silicate minerals and amorphous material. The fault zones were sectioned into six layers (~160 µm thick for each layer) parallel to the fault zone boundary for OSL analyses. Quartz grains from all the layers except the one immediately adjacent to the stationary side of the sandstone cylinder show De of 'effectively' 0 Gy indicating a full resetting of OSL signals. The partial resetting of OSL signal in the layer adjacent to the stationary side of the cylinder indicates the temperature (T

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.)

PIXE multivariate statistics and OSL investigation for the classification and dating of archaeological pottery excavated at Tell Al-Rawda site, Syria

Energy Technology Data Exchange (ETDEWEB)

Bakraji, E.H., E-mail: cscientificl@aec.org.sy [Archaeometry Laboratory, Chemistry Department, Atomic Energy Commission of Syria, P. O. Box 6091, Damascus (Syrian Arab Republic); Rihawy, M.S. [Archaeometry Laboratory, Chemistry Department, Atomic Energy Commission of Syria, P. O. Box 6091, Damascus (Syrian Arab Republic); Castel, C. [CNRS – Maison de l’Orient et de la Méditerranée, Laboratoire “Archéorient”, CNRS/Université Lumière-Lyon 2 (France); Abboud, R. [Archaeometry Laboratory, Chemistry Department, Atomic Energy Commission of Syria, P. O. Box 6091, Damascus (Syrian Arab Republic)

2015-03-15

Highlights: •PIXE and OSL methods were used to classify and date pottery from Tell Al-Rawda site. •Three groups were classified using PIXE, which suggest different sources of the clay. •OSL was used for dating the site and the date found was consistent with typology. -- Abstract: Particle Induced X-ray Emission (PIXE) technique has been utilised to study 48 Syrian ancient pottery fragments taken from excavations at Tell Al-Rawda site. Eighteen elements (Mg, Al, Si, P, S, K, Ca, Ti, Mn, Fe, Ni, Zn, As, Br, Rb, Sr, Y, and Pb) were determined. The elements concentrations have been processed using two multivariate statistical methods, to classify the pottery where one main group and other two small groups were defined. In addition, four samples from different places on the site were subjected to optically stimulated luminescence (OSL) dating. The average age obtained using a single aliquot regeneration (SAR) protocol was found to be 4350 ± 240 year.

Establishing a luminescence chronology for a palaeosol-loess profile at Tokaj (Hungary): A comparison of quartz OSL and polymineral IRSL signals

DEFF Research Database (Denmark)

Schatz, Ann-Kathrin; Buylaert, Jan-Pieter; Murray, Andrew

2012-01-01

We present a comparative study of quartz OSL, polymineral IRSL at low temperature (50 °C, IR50) and post-IR elevated temperature (290 °C) IRSL (pIRIR290) feldspar dating on nine samples from the Tokaj loess section in NE Hungary (SE Europe). Preheat plateau tests show a drop in quartz OSL De...... between 160 and 240 °C but above 240 °C a clear De plateau is present. Quartz OSL SAR is shown to be generally appropriate to these samples (recycling, recuperation) but a satisfactory dose recovery result was only obtained when a dose was added to a sample without any prior optical or thermal pre...... of the Tokaj loess has been deposited during MIS 3 (60–24 ka), with periods of soil formation occurring during the onset of MIS 3 (≥58 ka) and between about 35 and 25 ka. Our results also indicate episodic deposition of loess and varying, non-linear sedimentation rates during MIS 3. Proxy analyses...

PIXE multivariate statistics and OSL investigation for the classification and dating of archaeological pottery excavated at Tell Al-Rawda site, Syria

International Nuclear Information System (INIS)

Bakraji, E.H.; Rihawy, M.S.; Castel, C.; Abboud, R.

2015-01-01

Highlights: •PIXE and OSL methods were used to classify and date pottery from Tell Al-Rawda site. •Three groups were classified using PIXE, which suggest different sources of the clay. •OSL was used for dating the site and the date found was consistent with typology. -- Abstract: Particle Induced X-ray Emission (PIXE) technique has been utilised to study 48 Syrian ancient pottery fragments taken from excavations at Tell Al-Rawda site. Eighteen elements (Mg, Al, Si, P, S, K, Ca, Ti, Mn, Fe, Ni, Zn, As, Br, Rb, Sr, Y, and Pb) were determined. The elements concentrations have been processed using two multivariate statistical methods, to classify the pottery where one main group and other two small groups were defined. In addition, four samples from different places on the site were subjected to optically stimulated luminescence (OSL) dating. The average age obtained using a single aliquot regeneration (SAR) protocol was found to be 4350 ± 240 year

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.

Synthesis and TL/OSL properties of a novel high-sensitive blue-emitting LiSrPO{sub 4}:Eu{sup 2+} phosphor for radiation dosimetry

Energy Technology Data Exchange (ETDEWEB)

Palan, C.B.; Koparkar, K.A.; Omanwar, S.K. [Sant Gadge Baba Amravati University, Department of Physics, Amravati (India); Bajaj, N.S. [Toshniwal Arts, Commerce and Science College, Sengoan, Hingoli District, MH (India); Soni, A. [Bhabha Atomic Research Centre, Radiological Physics and Advisory Division, Mumbai (India)

2016-07-15

In this study, a series of Eu{sup 2+}-doped LiSrPO{sub 4} phosphors were synthesized via solid-state method. The structural and morphological characterizations were done through X-ray diffraction and scanning electronic microscope. Additionally, the photoluminescence (PL), thermoluminescence (TL) and optically stimulated luminescence (OSL) behaviours of LiSrPO{sub 4}:Eu{sup 2+} phosphors were studied. The LiSrPO{sub 4}:Eu{sup 2+} phosphor shows OSL sensitivity about 8 times than that of α-Al{sub 2}O{sub 3}:C phosphor and 6 times than that of LiMgPO{sub 4}:Tb{sup 3+}, B phosphor. Moreover, TL sensitivity was about 15 times more as compared to α-Al{sub 2}O{sub 3}:C phosphor. The kinetic parameters of TL curve were calculated using peak shape method. In TL/OSL mode, dose-response was almost linear nature, in the range of measurement. The minimum detectable dose was found to be 25.18 μGy with 3σ of background. Also, reusability was also studies, which shows the phosphor can be reusable for 10 cycles with 0.1 % change in OSL output. (orig.)

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.

Persistent luminescence, TL and OSL characterization of beta irradiated SrAl2O4:Eu2+, Dy3+ combustion synthesized phosphor

International Nuclear Information System (INIS)

Zúñiga-Rivera, N.J.; García, R.; Rodríguez-Mijangos, R.; Chernov, V.; Meléndrez, R.; Pedroza-Montero, M.; Barboza-Flores, M.

2014-01-01

The persistent luminescence (PLUM), thermoluminescence (TL) and optically stimulated luminescence (OSL) properties of strontium aluminates co-doped with Eu +2 and Dy +3 exposed to beta radiation is reported. The phosphor was synthesized by the combustion synthesis method employing a highly exothermic redox reaction between the metal nitrates [Al(NO 3 ) 3 , Sr(NO 3 ) 2 , Eu(NO 3 ) 3 and Dy(NO 3 ) 3 ] and organic fuel carbohydrazide (CH 6 N 4 O). The long decay PLUM emission, TL and OSL were measured as a function of beta radiation dose. A wide emission band centered at 510 nm (green) related to Eu 2+ ions and lattice defects were observed for the synthesized samples. The presence of a variety of defects and aggregates were responsible for the observed broad 100 °C peaked TL glow curve of the irradiated sample which is composed of several overlapped TL peaks. The existence of multiple trapping levels, with different trapping/detrapping probabilities, is behind the particular features for the PLUM, TL and OSL emissions. We conclude that in the SrAl 2 O 4 :Eu 2+ , Dy 3+ phosphors, the low temperature TL peaked around 30–75 °C is responsible for the PLUM emission and those around 100 °C were related to very stable trapping states which provide suitable radiation storage properties to be used as a PLUM/TL/OSL radiation phosphor

TL, OSL and C-14 dating results of the sediments and bricks from mummified nuns' grave

International Nuclear Information System (INIS)

Tudela, Diego R.G.; Tatumi, Sonia H.; Yee, Marcio; Brito, Silvio L.M.

2012-01-01

This paper presents the results of TL and OSL dating of soil and fragments of bricks from a grave, which was occupied by two mummified nuns, found at 'Luz' Monastery, located in the state of Sao Paulo, Brazil. The TL and OSL ages were compared to C-14 dating ones obtained from bone collagens of the mummies. The majority of the ages is related to the eighteenth century. The gamma-ray spectroscopy was used to evaluate natural radioisotope concentrations in the samples, and by using these concentrations the annual dose rates, from 3.0 to 5.3 Gy/kyr, were obtained. Neutron activation analysis was performed and the radioisotope contents results are in agreement with those obtained by gamma-ray spectroscopy. The contents of U, Th and Ce elements were higher than those found in usual sediments. (author)

Assessment of influence of OSL dosimeters in the skin dose in radiotherapy: study for Monte Carlo simulation; Avaliacao da influencia de dosimetros OSL na dose na pele em radioterapia: estudo por simulacao Monte Carlo

Energy Technology Data Exchange (ETDEWEB)

Schuch, Franciely F.; Nicolucci, Patricia, E-mail: franschuch@yahoo.com.br [Universidade de Sao Paulo (USP), Ribeiraoo Preto, SP (Brazil)

2017-11-01

The interest in optically stimulated luminescence (OSL) dosimetry materials is growing due to its potential use in quality control in Radiotherapy. The use of these dosimeters for in vivo dosimetry, however, may influence the dose to the skin and deeper tissues in the patient. The goal of this study is to evaluate the influence of the OSL Al{sub 2}O{sub 3} material in dose deposited in the skin and deep in Radiotherapy. Monte Carlo simulation is used to evaluate this purpose when OSL dosimeters of Al{sub 2}O{sub 3} are positioned on the skin surface of the patient. Percentage depth dose curves for clinical beams of 6 and 10 MV were simulated with and without the presence of the dosimeter on the surface of a water phantom. The results showed a decrease of doses in regions close to the surface of the skin. In the build-up region, the maximum decreases of dose produced by the presence of the dosimeters were 52,5% and 47,5% for the 6 and 10 MV beams, respectively. After the build-up region, there are not significant changes in the doses for any of the used beams. The differences of doses found are due to the influence of the dosimetric material on the relative fluence of electrons near the end surface of the dosimeter. Thus, the results showed that the presence of the dosimetric material on the surface interferes on the skin dose. However, these dosimeters do not cause dose variations in depths of clinical interest, allowing its application in routine in vivo dosimetry in Radiotherapy. (author)

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).

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.)

SU-F-T-327: Total Body Irradiation In-Vivo Dose Measurements Using Optically Stimulated Luminescence (OSL) NanoDots and Farmer Type Ion Chamber

International Nuclear Information System (INIS)

Kaur, H; Kumar, S; Sarkar, B; Ganesh, T; Giri, U; Jassal, K; Rathinamuthu, S; Gulia, G; Gopal, V; Mohanti, B; Munshi, A

2016-01-01

Purpose: This study was performed to analyze the agreement between optically stimulated luminescence (OSL) nanoDots measured doses and 0.6 cc Farmer type ionization chamber measured doses during total body irradiation (TBI). Methods: In-vivo dose measurements using OSL nanoDots and Farmer chamber were done in a total of twelve patients who received TBI at our center by bilateral parallel-opposed beams technique. In this technique, the patient is kept inside the TBI box which is filled with rice bags and irradiated using two bilateral parallel opposed beams of 40×40 cm"2 size with 45° collimator rotation at an SSD of 333.5 cm in an Elekta Synergy linear accelerator. All patients received a dose of 2 Gy in single fraction as conditioning regimen. The beams were equally weighted at the midplane of the box. The nanoDots were placed over forehead, right and left neck, right and left lung, umbilicus, right and left abdomen, medial part of thigh, knee and toe. A 0.6 cc Farmer chamber was placed in between the thighs of the patient. Measured doses are reported along with the statistical comparisons using paired sample t-test. Results: For the above sites the mean doses were 212.2±21.1, 218.2±7.6, 218.7±9.3, 215.6±9.5, 217.5±11.5, 214.5±7.7, 218.3±6.8, 221.5±15, 229.1±11.0, 220.5±7.7 and 223.3±5.1 cGy respectively. For all OSL measurements the mean dose was 218.6±11.8 cGy. Farmer chamber measurements yielded a mean dose of 208.8±15.6 cGy. Statistical analysis revealed that there was no significant difference between OSL measured doses in forehead, right and left neck, right and left lung, umbilicus, right and left abdomen and toe and Farmer chamber measured doses (0.72≤p≤0.06). However the mean OSL doses at thigh and knee were statistically different (p<0.05) from the Farmer chamber measurements. Conclusion: OSL measurements were found to be in agreement with Farmer type ionization chamber measurements in in-vivo dosimetry of TBI.

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

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)

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)

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

TL, OSL and C-14 dating results of the sediments and bricks from mummified nuns' grave

Energy Technology Data Exchange (ETDEWEB)

Tudela, Diego R.G.; Tatumi, Sonia H.; Yee, Marcio; Brito, Silvio L.M., E-mail: tatumi@fatecsp.br [Faculdades de Tecnologia de Sao Paulo (FATECs/CEETEPS/UNESP), Sao Paulo, SP (Brazil). Centro Estadual de Educacao Tecnologica Paula Souza; Morais, Jose L.; Morais, Daisy de; Piedade, Silvia C. [Universidade de Sao Paulo (USP), SP (Brazil). Museu de Arqueologia e Etnologia; Munita, Casimiro S.P.; Hazenfratz, Roberto [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2012-06-15

This paper presents the results of TL and OSL dating of soil and fragments of bricks from a grave, which was occupied by two mummified nuns, found at 'Luz' Monastery, located in the state of Sao Paulo, Brazil. The TL and OSL ages were compared to C-14 dating ones obtained from bone collagens of the mummies. The majority of the ages is related to the eighteenth century. The gamma-ray spectroscopy was used to evaluate natural radioisotope concentrations in the samples, and by using these concentrations the annual dose rates, from 3.0 to 5.3 Gy/kyr, were obtained. Neutron activation analysis was performed and the radioisotope contents results are in agreement with those obtained by gamma-ray spectroscopy. The contents of U, Th and Ce elements were higher than those found in usual sediments. (author)

Validation and dosimetric evaluation employing the techniques of TL and OSL of thermoluminescent materials for application in the dosimetry of clinical beams of electrons used in total irradiation of the skin - TSI

International Nuclear Information System (INIS)

Almeida, Shirlane Barbosa de

2017-01-01

In vivo dosimetry has become an important role for the treatment of total skin irradiation within a rigorous quality assurance program that should be an integral part of the radiotherapy departments. TSI dosimetry is difficult because of the complexity of the treatment in assessing dose uniformity and measuring the dose absorbed at shallow depths throughout the skin surface extent, resulting in a wide variation in dose distribution. The TLDs have proven to be very useful for the distribution and verification of the dose prescribed for the patient as the dose may differ from place to place due to patient body geometry, overlapping of structures and asymmetries of the radiation field. The use of TLDs in vivo can identify variations in the prescribed dose because its measurement accuracy and great precision. Several types of dosimeters have been used in the radiotherapy sectors, the most commonly used are Lithium Fluride (TLD-100), where it obtains a long history in this type of application. New dosimetric materials have gained great importance in the dosimetry of clinical electron beams, such as Dysprosium-doped Calcium Sulphate (TL) and Carbon doped (OSL) based Aluminum Oxide, This work evaluates the performance of the respective thermoluminescent dosimeters and the optically stimulated luminescence in the dosimetry of clinical electron beams used in total irradiation of the skin. (author)

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.)

Stability of fine-grained TT-OSL and post-IR IRSL signals from a c. 1 Ma sequence of aeolian and lacustrine deposits from the Nihewan Basin (northern China)

DEFF Research Database (Denmark)

Liu, Jinfeng; Murray, Andrew Sean; Buylaert, Jan-Pieter

2016-01-01

We tested the suitability of the fine-grained quartz (4–11 μm) Optical Stimulated Luminescence (OSL) and thermally-transferred OSL (TT-OSL), and the fine-grained polymineral (4–11 μm) post-infrared IRSL (post-IR IRSL or pIRIR) signals for dating samples from aeolian-lacustrine deposits from...... accurate ones; nevertheless, these ages provide the first long series absolute chronology for study of local palaeolithic and geomorphic evolution history aside from the  magnetostratigraphical results available before this research....

SU-F-T-327: Total Body Irradiation In-Vivo Dose Measurements Using Optically Stimulated Luminescence (OSL) NanoDots and Farmer Type Ion Chamber

Energy Technology Data Exchange (ETDEWEB)

Kaur, H; Kumar, S; Sarkar, B; Ganesh, T; Giri, U; Jassal, K; Rathinamuthu, S; Gulia, G; Gopal, V; Mohanti, B; Munshi, A [Fortis Memorial Research Institute, Gurgaon, Haryana (India)

2016-06-15

Purpose: This study was performed to analyze the agreement between optically stimulated luminescence (OSL) nanoDots measured doses and 0.6 cc Farmer type ionization chamber measured doses during total body irradiation (TBI). Methods: In-vivo dose measurements using OSL nanoDots and Farmer chamber were done in a total of twelve patients who received TBI at our center by bilateral parallel-opposed beams technique. In this technique, the patient is kept inside the TBI box which is filled with rice bags and irradiated using two bilateral parallel opposed beams of 40×40 cm{sup 2} size with 45° collimator rotation at an SSD of 333.5 cm in an Elekta Synergy linear accelerator. All patients received a dose of 2 Gy in single fraction as conditioning regimen. The beams were equally weighted at the midplane of the box. The nanoDots were placed over forehead, right and left neck, right and left lung, umbilicus, right and left abdomen, medial part of thigh, knee and toe. A 0.6 cc Farmer chamber was placed in between the thighs of the patient. Measured doses are reported along with the statistical comparisons using paired sample t-test. Results: For the above sites the mean doses were 212.2±21.1, 218.2±7.6, 218.7±9.3, 215.6±9.5, 217.5±11.5, 214.5±7.7, 218.3±6.8, 221.5±15, 229.1±11.0, 220.5±7.7 and 223.3±5.1 cGy respectively. For all OSL measurements the mean dose was 218.6±11.8 cGy. Farmer chamber measurements yielded a mean dose of 208.8±15.6 cGy. Statistical analysis revealed that there was no significant difference between OSL measured doses in forehead, right and left neck, right and left lung, umbilicus, right and left abdomen and toe and Farmer chamber measured doses (0.72≤p≤0.06). However the mean OSL doses at thigh and knee were statistically different (p<0.05) from the Farmer chamber measurements. Conclusion: OSL measurements were found to be in agreement with Farmer type ionization chamber measurements in in-vivo dosimetry of TBI.

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

DEFF Research Database (Denmark)

Lapp, Torben; Jain, Mayank; Ankjærgaard, Christina

2009-01-01

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

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.

Single-grain and multi-grain OSL dating of river terrace sediments in the Tabernas Basin, SE Spain

DEFF Research Database (Denmark)

Geach, M.R.; Thomsen, Kristina Jørkov; Buylaert, Jan-Pieter

2015-01-01

River terraces represent important records of landscape response to e.g. base-level change and tectonicmovement. Both these driving forces are important in the southern Iberian Peninsula. In this study,Optically Stimulated Luminescence (OSL) dating was used to date two principal river terraces...

New data on OSL dating of Early Khalynian deposits of Northern Caspian

Science.gov (United States)

Sychev, Nikita; Yanina, Tamara; Svitoch, Alexander; Kurbanov, Redzhep; Badyukova, Ekaterina

2016-04-01

Ponto-Caspian region is the key region the study of which can provide information about the paleogeographic history of the central Eurasia, particularly revealing the history of the East European Plain, the Caucasus and Central Asia. However, despite the long history of the study, today there is no accepted general stratigraphic scheme of the Caspian Sea. One of the most interesting and important stages of Late Pleistocene history of Caspian is Khalynian transgression which is divided into two major phases: early and ate. In the Caspian lowland Lower Khalynian stage are represented by a unique type of deposit - "chocolate clays". A distinctive feature of these sediments is widely distributed among Lower Khalynian deposits of Northern Caspian and the Volga region. All clay deposits are confined to the diverse origins of depression before-Khalynian relief. Chocolate clays formation consists of facies: mono-clay (typological), layered, sand- and silty-clay (Svitoch, Yanina, 1997). Determining the age of chocolate clays by optically stimulated luminescence (OSL) in our view will allow bettering the understanding of their genesis. Age of chocolate clays of Lower Volga was widely dated using the radiocarbon. However, the existing chronology is controversial, raises a number of issues, primarily due to the material of which are used for dating - thin shells of Caspian mollusks of the Didacna Eichw. genus, which are characterized by a significant isotopic exchange with the enclosing sediments (Arslanov, 2015). Lower Volga region is characterized by very complex geological structure of the Late Pleistocene deposits (alternating continental aeolian, alluvial and slope sediments with marine Caspian deposits of different age). There are many conflicting opinions, not only with respect to paleogeographic features of the area, but also to its precise chronology. The differences in opinion over the age of the individual stages of development of the Caspian Sea (transgressions and

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)

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.

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)

Investigation of OSL signal of resistors from mobile phones for accidental dosimetry

International Nuclear Information System (INIS)

Mrozik, A.; Marczewska, B.; Bilski, P.; Gieszczyk, W.

2014-01-01

Resistors from mobile phones, usually located near the human body, are considered as individual dosimeters of ionizing radiation in emergency situations. The resistors contain Al 2 O 3 , which is optically stimulated luminescence (OSL) material sensitive to ionizing radiation. This work is focused on determination of dose homogeneity within mobile phones which was carried out by OSL measurements of resistors placed in different parts inside the mobile phone. Separate, commercially available resistors, similar in the shape and size to the resistors from circuit board of the studied mobile phone, were situated in different locations inside it. The irradiations were performed in uniform 60 Co and 137 Cs radiation fields, with the mobile phones connected and not connected to the cellular network. The dose decrease of 9% was measured for original resistors situated between circuit board and battery, in comparison to the dose at the front of the phone. The resistors showed the lower signal when the mobile phone was connected to the cellular network, due to higher temperature inside the housing. The profile of fading was investigated within 3 month period for resistors irradiated with 1 Gy of gamma rays to estimate of the fading coefficient. - Highlights: • Impact of a mobile phone mode (switched on/off) on absorbed dose by resistors was showed. • The influence of the temperature during irradiation on absorbed dose was measured. • Dose distribution inside of a mobile phone was performed. • Fading factor of resistors was calculated

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)

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

International Nuclear Information System (INIS)

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

2016-01-01

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

Optically stimulated luminescence (OSL) dating of quartzite cobbles from the Tapada do Montinho archaeological site (east-central Portugal)

DEFF Research Database (Denmark)

Sohbati, Reza; Murray, Andrew S.; Buylaert, Jan-Pieter

2012-01-01

The burial age of an alluvially deposited cobble pavement at the Tapada do Montinho archaeological site (east-central Portugal) is investigated using optically stimulated luminescence (OSL) dating. Measurements on the cobbles (quartzite clasts) were carried out on intact slices and large aliquots...

In-situ Long-range Alpha Particles and X-ray Detection for Thin-film Pd Cathodes During Electrolysis in Li_2SO_4/H_2O

Science.gov (United States)

Lipson, A. G.; Roussetski, A. S.; Castano, C. H.; S-O, Kim; Miley, G. H.

2002-03-01

Measurements of long-range alpha and soft X-ray emissions have been performed using cyclotron calibrated CR-39 plastic track and LiF/Al_2O_3:C-Thermo-Luminescent (TLD) detectors. Application of CR-39 and TLD detectors to the surface of the thin Pd film-cathodes sputtered on the insulator substrate (glass, Al_2O_3, PMMA) allows detection of both alpha and soft X-ray emissions simultaneously with excess heat measurements during electrolysis using 1 Molar Li_2SO_4/H_20 electrolyte. The alpha particles in the range of 8.0 d> 6.0 μm) were detected upon the electrolysis. Those alpha-tracks are quite unique, never having been observed during CR-39 exposure with trans-uranium alpha -sources (Am^241, Pu^239). The TLD measurement shows generation of the low intensity 5.0-10.0 keV X-ray quanta (Φx < 5.0 s -1*cm-2) accompanying the alpha emission.

OSL-SAR dating of sediments from Brazilian aeolian system: Dama Branca, Rio de Janeiro, morphodynamic study

Energy Technology Data Exchange (ETDEWEB)

Carmo, Lucas S. do; Watanabe, Shigueo, E-mail: lsatiro@usp.br, E-mail: lacifid@if.usp.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); DeWitt, Regina, E-mail: dewittr@ecu.edu [East Carolina University (ECU), Greenville, NC (United States)

2017-07-01

It has been reported that the formation and stabilization of coastal dune fields in Brazil have a dependence on the climate changes and Relative Sea Level (RSL) variations. A few topics regarding the morphodynamics of coastal aeolian systems in Brazil can be the RSL variations in the Holocene and weather conditions. In this work, a dune field known as 'Dama Branca', located in the town of Cabo Frio, Rio de Janeiro, has been studied to understand its formation and stabilization. Dating by trapped charge dating techniques as Optically Stimulated Luminescence (OSL) using the Single Aliquot Regenerative protocol (SAR), help to understand the formation and dynamics of aeolian systems in Brazil. Samples from a dune were collected from different heights and points for dating. The results obtained by OSL-SAR showed that ages decrease as the height from the dune base increase and older samples are found in deeper horizontal positions. The ages for the base of the studied dunes indicated that its stabilization occurred during the recess of the sea level. (author)

OSL-SAR dating of sediments from Brazilian aeolian system: Dama Branca, Rio de Janeiro, morphodynamic study

International Nuclear Information System (INIS)

Carmo, Lucas S. do; Watanabe, Shigueo; DeWitt, Regina

2017-01-01

It has been reported that the formation and stabilization of coastal dune fields in Brazil have a dependence on the climate changes and Relative Sea Level (RSL) variations. A few topics regarding the morphodynamics of coastal aeolian systems in Brazil can be the RSL variations in the Holocene and weather conditions. In this work, a dune field known as 'Dama Branca', located in the town of Cabo Frio, Rio de Janeiro, has been studied to understand its formation and stabilization. Dating by trapped charge dating techniques as Optically Stimulated Luminescence (OSL) using the Single Aliquot Regenerative protocol (SAR), help to understand the formation and dynamics of aeolian systems in Brazil. Samples from a dune were collected from different heights and points for dating. The results obtained by OSL-SAR showed that ages decrease as the height from the dune base increase and older samples are found in deeper horizontal positions. The ages for the base of the studied dunes indicated that its stabilization occurred during the recess of the sea level. (author)

Study of sensitivity change of OSL signals from quartz and feldspars as a function of preheat temperature

DEFF Research Database (Denmark)

Jungner, H.; Bøtter-Jensen, L.

1994-01-01

and as a result, the equivalent dose (ED) would be underestimated. A study of sensitivity changes in feldspars and quartz was carried out with emphasis on the effect of preheat and annealing on the OSL signal. Measurement results obtained are presented, and possible elimination of errors in dating caused...

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)

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)

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)

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.

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)

An investigation of coseismic OSL / TL time zeroing of quartz gouge based on low- to high-velocity friction experiments

Science.gov (United States)

Akasegawa, K.; Oohashi, K.; Hasebe, N.; Miura, K.

2016-12-01

To determine an age of coseismic event of an active fault, we generally examine crosscutting relationship between faults and overlying strata by trenching. However, we could not apply this method in case there are no overlying young strata in the vicinity of the fault zones. The alternative is a dating of fault zone materials whose age experienced resetting with seismic fault slip (for example, the ESR method;. Ikeya et al,1982; the OSL and TL methods). The idea behinds to the OSL (optically stimulated luminescence) and TL (thermoluminescence) dating methods for a determination of paleo-earthquake event is the accumulated natural radiation damage becomes to zero (time zeroing) by the frictional heating and grinding. However, physical and geological conditions required to induce time zeroing is not well understood because there is only few experimental investigations under the limited conditions (Hiraga et al,2004;. Kim et al, 2014) . In this study, we conduct low- to high-velocity friction experiments using quartz gouge under various experimental conditions (e.g., normal stress, displacement, moisture content) to establish an empirical relationship and physical and geological conditions of coseismic OSL time zeroing. In this experiment, we carry out the friction experiments using quartz in Tsushigawa granite taken from the east wall of the Nojima fault Ogura trench site, which was excavated in 2015. Samples were taken from the most distant position from the fault in the trench site. The samples were clashed using a mortar and sieved to a grain size of treatment. The residual is user for the friction experiments after having known radiation dose using an artificial gamma-ray source. In this presentation, we show results of the friction experiments and dating of the quartz gouge and discuss physical and geological conditions of OSL time zeroing. References Okumura, T., and Shitaoka, Y., 2011. Engineering Geology of Japan, No. 1, 5-17. Hiraga, S., Yoshimoto, A., and

Reliability of equivalent-dose determination and age-models in the OSL dating of historical and modern palaeoflood sediments

DEFF Research Database (Denmark)

Medialdea, Alicia; Thomsen, Kristina Jørkov; Murray, Andrew Sean

2014-01-01

model to small aliquot (similar to 30 grains) dose distributions. From our study we conclude that these and similar young slack-water flood deposits can be accurately dated using quartz OSL, opening up the possibility of establishing time series of flood discharge in catchments for which no instrumental...

Validation and dosimetric evaluation employing the techniques of TL and OSL of thermoluminescent materials for application in the dosimetry of clinical beams of electrons used in total irradiation of the skin - TSI; Validação e avaliação dosimétrica empregando as técnicas de TL e OSL de materiais termoluminescentes para aplicação na dosimetria de feixes clínicos de elétrons utilizados na irradiação total da pele

Energy Technology Data Exchange (ETDEWEB)

Almeida, Shirlane Barbosa de

2017-07-01

In vivo dosimetry has become an important role for the treatment of total skin irradiation within a rigorous quality assurance program that should be an integral part of the radiotherapy departments. TSI dosimetry is difficult because of the complexity of the treatment in assessing dose uniformity and measuring the dose absorbed at shallow depths throughout the skin surface extent, resulting in a wide variation in dose distribution. The TLDs have proven to be very useful for the distribution and verification of the dose prescribed for the patient as the dose may differ from place to place due to patient body geometry, overlapping of structures and asymmetries of the radiation field. The use of TLDs in vivo can identify variations in the prescribed dose because its measurement accuracy and great precision. Several types of dosimeters have been used in the radiotherapy sectors, the most commonly used are Lithium Fluride (TLD-100), where it obtains a long history in this type of application. New dosimetric materials have gained great importance in the dosimetry of clinical electron beams, such as Dysprosium-doped Calcium Sulphate (TL) and Carbon doped (OSL) based Aluminum Oxide, This work evaluates the performance of the respective thermoluminescent dosimeters and the optically stimulated luminescence in the dosimetry of clinical electron beams used in total irradiation of the skin. (author)

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

Persistent luminescence, TL and OSL characterization of beta irradiated SrAl{sub 2}O{sub 4}:Eu{sup 2+}, Dy{sup 3+} combustion synthesized phosphor

Energy Technology Data Exchange (ETDEWEB)

Zúñiga-Rivera, N.J. [Departamento de Física, Posgrado en Nanotecnología, Universidad de Sonora, Hermosillo, Sonora 83000 (Mexico); García, R.; Rodríguez-Mijangos, R.; Chernov, V.; Meléndrez, R.; Pedroza-Montero, M. [Departamento de Investigación en Física, Universidad de Sonora, Hermosillo, Sonora 83000 (Mexico); Barboza-Flores, M., E-mail: mbarboza@cifus.uson.mx [Departamento de Investigación en Física, Universidad de Sonora, Hermosillo, Sonora 83000 (Mexico)

2014-05-01

The persistent luminescence (PLUM), thermoluminescence (TL) and optically stimulated luminescence (OSL) properties of strontium aluminates co-doped with Eu{sup +2} and Dy{sup +3} exposed to beta radiation is reported. The phosphor was synthesized by the combustion synthesis method employing a highly exothermic redox reaction between the metal nitrates [Al(NO{sub 3}){sub 3}, Sr(NO{sub 3}){sub 2}, Eu(NO{sub 3}){sub 3} and Dy(NO{sub 3}){sub 3}] and organic fuel carbohydrazide (CH{sub 6}N{sub 4}O). The long decay PLUM emission, TL and OSL were measured as a function of beta radiation dose. A wide emission band centered at 510 nm (green) related to Eu{sup 2+} ions and lattice defects were observed for the synthesized samples. The presence of a variety of defects and aggregates were responsible for the observed broad 100 °C peaked TL glow curve of the irradiated sample which is composed of several overlapped TL peaks. The existence of multiple trapping levels, with different trapping/detrapping probabilities, is behind the particular features for the PLUM, TL and OSL emissions. We conclude that in the SrAl{sub 2}O{sub 4}:Eu{sup 2+}, Dy{sup 3+} phosphors, the low temperature TL peaked around 30–75 °C is responsible for the PLUM emission and those around 100 °C were related to very stable trapping states which provide suitable radiation storage properties to be used as a PLUM/TL/OSL radiation phosphor.

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

International Nuclear Information System (INIS)

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

1999-01-01

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

High resolution OSL and post-IR IRSL dating of the last interglacialeglacial cycle at the Sanbahuo loess site (northeastern China)

DEFF Research Database (Denmark)

Yi, Shuangwen; Buylaert, Jan-Pieter; Murray, Andrew

2015-01-01

Northeastern China is located in the East Asian monsoon region; it is sensitive to both high and low latitude global climate systems. Loess deposits in the region have considerable potential as sensitive archives of past climate changes. However, research into loess deposition and climate change...... to have been a period of fast loess deposition at ~62 ka, perhaps indicative of winter monsoon intensification with a very cold and dry climate that lead to a serious desertification of dunefields in northeastern China. © 2015 Elsevier B.V. All rights reserved....... in this region is restricted by the lack of independent age control. In this study, coarse-grained quartz SAR OSL and K-feldspar post-IR infrared (IR) stimulated luminescence (post-IR IRSL; pIRIR290) methods have been used to date the Sanbahuo loess site in northeastern China. The quartz OSL characteristics...

Radiotherapy verification film for estimating cumulative entrance skin exposure for fluoroscopic examinations

International Nuclear Information System (INIS)

Geise, R.A.; Ansel, H.J.

1990-01-01

Measurement of skin entrance exposures during fluoroscopic procedures is complicated by the use of automatic exposure control devices and the presence of contrast media. Due to variability in positioning spot films from patient to patient, standard dosimeters, such as thermoluminescent, cannot be properly placed on the skin prior to examination. Prepackaged film of the type used for portal verification in radiation therapy held next to the patient's skin in a specially modified patient examination gown was found to be useful for determining the entrance skin exposure from both fluoroscopy and spot films during air contrast barium enema exams. The usable sensitivity range of this film has been found satisfactory for exposure measurements at exposures and kVps typically used for gastrointestinal fluoroscopic procedures. Errors in exposure estimates due to changes in film speed and contrast with kVp are less than 5% for the range of kVps used. Errors from variations in beam quality due to the adjacency of scattering material are approximately 5%. Entrance exposures determined with film agreed with those determined from TLD measurements to within 21%, with an average difference of 9%

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

Sources of uncertainties in OSL dating of archaeological mortars: The case study of the Roman amphitheatre “Palais-Gallien” in Bordeaux

International Nuclear Information System (INIS)

Urbanova, P.; Hourcade, D.; Ney, C.; Guibert, P.

2015-01-01

Archaeological mortars are more convenient and much more representative for the chronology of buildings than brick or wood constructions that can be re-used from older buildings. Before dating unknown samples of mortars, further investigation of OSL from mortars is required and the most efficient methodology needs to be established. In this study we compared the ages obtained by OSL dating of quartz extracted from mortars of the Roman amphitheatre Palais-Gallien in Bordeaux with independent age information. Resetting of the OSL signal occurred during the preparation of mortar when grains of sand (quartz) were extracted and mixed with lime and water. The mortar was subsequently hidden from light by embedding within the structure which is the event to be dated. Various factors contribute to uncertainties in the age determination. The frequency of measured equivalent doses reveals a large scattering. Optical bleaching of certain grains can be partial due to the short duration of the exposure to light. We worked with the single grain technique in order to find and select the grains that were sufficiently exposed to daylight. To determine the average equivalent dose, we tried three different approaches: a calculation of an arithmetic mean and one following either the central age model or the 3-parameter minimum age model, the latter turned out to be the only relevant way to evaluate the experimental data. The proportion of grains included in the calculation of the average equivalent dose represents 2.7–4.7 % of the overall analysed grains. The results obtained for the three out of four samples are approaching the expected age, however, the minimum doses and the corresponding ages are significantly over-estimated in case of two samples. The studied material is very coarse, which causes heterogeneity of irradiation at the single grain scale, and contributes to a dispersion of equivalent doses. Different analytical methods (scanning electron microscopy with energy

Quartz OSL dating of late quaternary Chinese and Serbian loess: A cross Eurasian comparison of dust mass accumulation rates

DEFF Research Database (Denmark)

Peric, Zoran; Adolphi, Emma Lagerbäck; Stevens, Thomas

2018-01-01

on multi-millennial timescales, with no detailed examination of dust MAR at the two ends of the Eurasian loess belt on shorter, sub-orbital scales. Here we present a detailed quartz optically stimulated luminescence (OSL) chronology from the Serbian Titel Loess Plateau (Veliki Surduk loess core...

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

International Nuclear Information System (INIS)

Pradhan, A.S.; Chatterjee, S.

2003-01-01

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

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)

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.

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)

Bioactivity characterization of 45S5 bioglass using TL, OSL and EPR: Comparison with the case of 58S sol-gel bioactive glass

Energy Technology Data Exchange (ETDEWEB)

Polymeris, G.S., E-mail: gspolymeris@ankara.edu.tr [Ankara University, Institute of Nuclear Sciences, 06100 Beşevler, Ankara (Turkey); Giannoulatou, V. [Ankara University, Institute of Nuclear Sciences, 06100 Beşevler, Ankara (Turkey); Solid State Section, Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Kyriakidou, A. [Solid State Section, Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Sfampa, I.K. [Nuclear Physics Laboratory, Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Theodorou, G.S. [Solid State Section, Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Şahiner, E.; Meriç, N. [Ankara University, Institute of Nuclear Sciences, 06100 Beşevler, Ankara (Turkey); Kitis, G. [Nuclear Physics Laboratory, Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Paraskevopoulos, K.M. [Solid State Section, Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

2017-01-01

The current work exploits the effective application of thermoluminescence (TL), optically stimulated luminescence (OSL) and the possibility of applying Electron Paramagnetic Resonance (EPR) for the discrimination between different bioactive responses in the case of the 45S5 bioactive glass (SiO{sub 2} 45, Na{sub 2}O 24.5, CaO 24.5, P{sub 2}O{sub 5} 6 in wt%), which was synthesized through melting process. These techniques are suggested mainly due to their low spectroscopic detection thresholds. The original 45S5 in grain size range of 20–40 μm was immersed in the Simulated Body Fluid (SBF) for various different immersion times ranging over one week. In this work the 110 °C TL peak, a specific OSL component and the EPR signal at g = 2.013 ascribed to oxygen hole center (OHC) are used due to their sensitivity to the different bioactive responses. For all luminescence and EPR components, the intensity plot versus immersion time yields sharp discontinuities, resulting in effective probes regarding the timescale for both the beginning as well as the end of the procedure of the crystalline HCAp formation respectively. On the contrary to the smooth decreasing pattern of both luminescence entities, the peak to peak amplitude of the EPR signal indicates an initial increase for the initial 16 min of immersion, followed by a further decrease throughout the immersion time duration. The discontinuities monitored for both sensitivity of TL, OSL and EPR, in conjunction with the discontinuities monitored for the sensitization of TL and OSL, when plotted versus immersion time, provide an individual time scale for each one of the chemical reactions involved in the five steps of the aforementioned procedure. According to the authors' best knowledge, scarce characterization techniques could provide this time scale frame, while it is the first time that such an application of OSL and EPR is attempted. Finally, the bioactive response of the 45S5 bioglass was compared with that

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

Estimation of eye lens dose during brain scans using Gafchromic XR-QA2 film in various multidetector CT scanners

International Nuclear Information System (INIS)

Akhilesh, Philomina; Jamhale, Shramika H.; Sharma, S.D.; Kumar, Rajesh; Datta, D.; Kulkarni, Arti R.

2017-01-01

The purpose of this study was to estimate eye lens dose during brain scans in 16-, 64-, 128- and 256-slice multidetector computed tomography (CT) scanners in helical acquisition mode and to test the feasibility of using radiochromic film as eye lens dosemeter during CT scanning. Eye lens dose measurements were performed using Gafchromic XR-QA2 film on a polystyrene head phantom designed with outer dimensions equivalent to the head size of a reference Indian man. The response accuracy of XR-QA2 film was validated by using thermoluminescence dosemeters. The eye lens dose measured using XR-QA2 film on head phantom for plain brain scanning in helical mode ranged from 43.8 to 45.8 mGy. The XR-QA2 film measured dose values were in agreement with TLD measured dose values within a maximum variation of 8.9%. The good correlation between the two data sets confirms the viability of using XR-QA2 film for eye lens dosimetry. (authors)

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)

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

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)

Dosimetric validation of planning system Eclipse 10 in partial breast irradiation treatments with IMRT; Validacion dosimetrica del sistema de planeacion Eclipse 10 en tratamientos de irradiacion parcial de mama con IMRT

Energy Technology Data Exchange (ETDEWEB)

Velazquez T, J. J.; Gutierrez M, J. G.; Ortiz A, C. S.; Chagoya G, A.; Gutierrez C, J. G., E-mail: jvelaesfm@gmail.com [Centro Medico Nacional Siglo XXI, Hospital de Oncologia, Departamentos de Fisica Medica y Radioterapia, Av. Cuauhtemoc 330, 03020 Mexico D. F. (Mexico)

2015-10-15

Partial breast irradiation is a new type of external radiation therapy to treat breast cancer in early clinical stages. Consist of administering to the channel surgical high doses of radiation in few treatment sessions. In this paper the dose calculations of the planning system Eclipse version 10 for a treatment of partial breast irradiation with X-rays beams (6 MV) intensity modulated were compared against the measurements made with OSL dosimeters and radio-chromic dye film. An anthropomorphic mannequin was used in which OSL dosimeters were collocated near the surface, an inside the radio-chromic dye film one plate; with this latest one dimensional dose distribution was measured. Previously dosimeters were calibrated irradiating them with a beam of X-rays 6 MV under the conditions specified in the IAEA-398 protocol. The OSL dosimeters were read in the Micro star Landauer equipment, the radio-chromic dye films were read with a scanner Epson 10000-Xl and analyzed with FilmCal and PTW Verisoft programs. The differences between measured and calculated dose were as follows: 3.6±1% for the OSL dosimeter and 96.3±1% of the analyzed points approved the gamma index criterion (3%, 3m m) when comparing the matrices of calculated dose and measured with the radio-chromic dye film. These results confirm the good dosimetric performance of planning system used under specific conditions used in the partial breast irradiation technique. (Author)

Dosimetric validation of planning system Eclipse 10 in partial breast irradiation treatments with IMRT

International Nuclear Information System (INIS)

Velazquez T, J. J.; Gutierrez M, J. G.; Ortiz A, C. S.; Chagoya G, A.; Gutierrez C, J. G.

2015-10-01

Partial breast irradiation is a new type of external radiation therapy to treat breast cancer in early clinical stages. Consist of administering to the channel surgical high doses of radiation in few treatment sessions. In this paper the dose calculations of the planning system Eclipse version 10 for a treatment of partial breast irradiation with X-rays beams (6 MV) intensity modulated were compared against the measurements made with OSL dosimeters and radio-chromic dye film. An anthropomorphic mannequin was used in which OSL dosimeters were collocated near the surface, an inside the radio-chromic dye film one plate; with this latest one dimensional dose distribution was measured. Previously dosimeters were calibrated irradiating them with a beam of X-rays 6 MV under the conditions specified in the IAEA-398 protocol. The OSL dosimeters were read in the Micro star Landauer equipment, the radio-chromic dye films were read with a scanner Epson 10000-Xl and analyzed with FilmCal and PTW Verisoft programs. The differences between measured and calculated dose were as follows: 3.6±1% for the OSL dosimeter and 96.3±1% of the analyzed points approved the gamma index criterion (3%, 3m m) when comparing the matrices of calculated dose and measured with the radio-chromic dye film. These results confirm the good dosimetric performance of planning system used under specific conditions used in the partial breast irradiation technique. (Author)

TL-OSL study of Li{sub 3}PO{sub 4}: Mg, Cu phosphor

Energy Technology Data Exchange (ETDEWEB)

Rahangdale, S. R., E-mail: sachin.rahangdale1@gmail.com; Wankhede, S. P. [Department of Physics, K.D.K.College of Engineering, Nagpur (India); Dhabekar, B. S. [RPAD, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Palikundwar, U. A.; Moharil, S. V. [Department of Physics, RTM Nagpur University, Nagpur, 440010 (India)

2015-08-28

In the present work, we report the thermoluminescence and optically stimulated luminescence properties of Mg and Cu doped Li{sub 3}PO{sub 4} phosphor. The phosphor was synthesized by precipitation method. The thermoluminescence dosimetric peak temperature for the phosphor varies with concentrations of Mg and Cu. Li{sub 3}PO{sub 4} shows good response to 470nm optical stimulation. The OSL sensitivity of the phosphor is approximately 12 times than that of standard Lithium magnesium phosphate. This study may help to develop this material for the application in real time dosimetry using optically stimulated luminescence.

Study on Public Exposure and External Radiation Level at Gamma Green House and around MINT Dengkil Complex Boarder

International Nuclear Information System (INIS)

Faizal Azrin Abdul Razalim; Ismail Sulaiman; Khairuddin Mohamad Kontol; Ahmad Bazlie Abdul Kadir; Noor Fadilla Ismail; Hassan Sham; Ahmad Zainuri Mohd Dzomir

2014-01-01

This paper will discussing on the measurement of external radiation and the dose level which is acceptable to the public around the Gamma Green House and the border between Malaysian Nuclear Agency and housing project developed by Mah Sing Group. This research is made to verify the level of safety, especially for civilians residing in this area and to ensure compliance with the limit that has been set by the authorities, AELB (BSS/2010). Measurement method used in this research by using survey meter, TLD and OSL. (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 aluminum oxide dosimeters using OSL technique in dosimetry of clinical photon beams on volumetric modulated arc treatment

International Nuclear Information System (INIS)

Villani, Daniel

2017-01-01

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

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)

Comparison of single-grain and small-aliquot OSL dose estimates in < 3000 years old river sediments from South India

DEFF Research Database (Denmark)

Thomas, P.J.; Jain, M.; Juyal, N.

2005-01-01

We report on OSL dose distributions derived from small-aliquot and single grains of quartz in young fluvial sediments sampled from the Penner River basin, South India. The single-grain dose distributions suggest that 13 out of 19 samples were well bleached. In many well-bleached samples, there wa......We report on OSL dose distributions derived from small-aliquot and single grains of quartz in young fluvial sediments sampled from the Penner River basin, South India. The single-grain dose distributions suggest that 13 out of 19 samples were well bleached. In many well-bleached samples......, there was an underestimation in the single-aliquot dose estimates as compared to those from the single grain-the difference between average dose estimates determined by the two methods ranged from similar to 1% to 31%. Such a dose underestimation was not detectable in poorly bleached samples. Various possible reasons...... perhaps be one of the reasons; this may occur because the stimulation wavelength affects the proportion of the medium and slow components in the initial signal. (c) 2004 Elsevier Ltd. All rights reserved....

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

OSL properties of three commonly available salt brands in India for its use in accident dosimetry

Science.gov (United States)

Singh, A. K.; Menon, S. N.; Kadam, S. Y.; Koul, D. K.; Datta, D.

2018-03-01

Thermally stimulated luminescence (TL) and Optically Stimulated Luminescence (OSL) characterization of three commonly available salt brands in India were undertaken for their application in accident dosimetry. The investigations showed that the luminescence properties differed to some extent with that reported in literature. Dosimetric properties of these salt samples showed that these can be useful in accident dosimetry. Based on the sensitization and fading behaviour of the samples a Single Aliquot Regenerative (SAR) protocol has been proposed for dose estimation.

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

Energy Technology Data Exchange (ETDEWEB)

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

1997-04-01

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

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

Science.gov (United States)

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

1997-02-01

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

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

International Nuclear Information System (INIS)

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

1997-01-01

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

Evaluation of aluminum oxide dosimeters using OSL technique in dosimetry of clinical photon beams on volumetric modulated arc treatment; Avaliacao de dosimetros de oxido de aluminio pela tecnica OSL na dosimetria de campos de fotons clinicos utilizados no tratamento radioterapico em arco modulado volumetrico

Energy Technology Data Exchange (ETDEWEB)

Villani, Daniel

2017-07-01

Treatment using Volumetric Modulated Arc Radiation Therapy is the most modern modality of conformational radiotherapy so that, with the overlapping of several fields, the dose distributions provide a perfect conformation to the tumor, reducing the probability of complications in adjacent normal tissues. In this sense, many efforts are being invested to improve dose distribution compliance as well as the integration of imaging techniques for tumor screening and correction of inter and intrafraction variations. To this end, an intensive monitoring of the quality of the processes and a quality assurance program are fundamental for patient safety and compliance with current legislation; besides the use of different dosimetry methodologies for intercomparison and validation of the results. The aim of this study is to evaluate and compare the performance of aluminum oxide (Al{sub 2}O{sub 3}:C) OSL dosimeters manufactured by Landauer Inc. with those produced by Rexon™ in the dosimetry of high energy photon clinical bundles used in Volumetric Modulated Arc Therapy - (VMAT) using different simulating objects. The dosimeters were characterized for gamma radiation of the {sup 60}Co and for clinical photon beams of 6 MV typical of treatments by VMAT under conditions of electronic equilibrium and maximum dose respectively. Performance tests of the TL and OSL readers used and repeatability of the samples were evaluated. After all tests, the dosimeters were irradiated in the simulation of different radiotherapy treatments by VMAT and their responses compared to the planning system. All types of dosimeters presented satisfactory results in verifying the doses of this type of planning simulation. The Al{sub 2}O{sub 3}:C dosimeters presented compatible results and validated by the other dosimeters and ionization chamber. Regarding the best technique, the OSL InLight commercial system presents greater practicality and versatility for use and application in the clinical routine

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

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

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

International Nuclear Information System (INIS)

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

2003-01-01

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

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

International Nuclear Information System (INIS)

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

2007-01-01

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

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)

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)

Single-grain OSL dating of Early Middle Palaeolithic deposits at Cuesta de la Bajada, Ebro Basin, Spain

Science.gov (United States)

Arnold, Lee; Demuro, Martina; Santonja, Manuel; Perez-Gonzalez, Alfredo; Pares, Josep

2013-04-01

The open-air site of Cuesta de la Bajada comprises a 2-2.5 m-thick sequence of fluvial-lacustrine sediments inset into the +50-60 m terrace deposits preserved along the south-eastern margins of the Alfambra river valley, Teruel, Spain. The main archaeological horizons lie ~20 m above the present-day river level and consists of an upward-fining sequence of massive fluvial silts and fine sands with dispersed gravels, detritic marls and shales that collectively overlie a series of planar bedded fluvial gravels. These units have yielded ~3000 lithic artefacts displaying reduction techniques characteristic of an early Middle Palaeolithic techno-complex, as well as a multitude of faunal remains indicative of a late Middle Pleistocene origin. The paucity of open-air Palaeolithic sites in the interior eastern sector of the Iberian Peninsula, and the relatively low number of documented early Middle Palaeolithic archives in this region, means that Cuesta de la Bajada is of key importance for understanding the coexistence/transition of Iberian Acheulean and Mousterian techno-complexes during the Middle Pleistocene period. Establishing reliable absolute chronologies at Cuesta de la Bajada remains essential for understanding the regional significance of this site. In an attempt to redress the existing chronological uncertainty we are undertaking an interdisciplinary dating study of the Middle Palaeolithic deposits using OSL dating, ESR/U-series dating of teeth and ESR dating of sedimentary quartz. Here we present results obtained using quartz single-grain OSL dating of 4 samples collected from a 7 m vertical profile bracketing the archaeological horizons. 2 samples were collected from the archaeology-bearing silt and fine sand horizons, while the remaining samples were obtained from well-bedded fine-sands and silts 3.5 m above and 3 m below the main excavation. The measured quartz grains are characterised by relatively bright OSL signals and typically display dose

OSL dating of fine-grained quartz from Holocene Yangtze delta sediments

DEFF Research Database (Denmark)

Sugisaki, Saiko; Buylaert, Jan-Pieter; Murray, Andrew

2015-01-01

Holocene flood events in the Yangtze River are associated with variations in East Asian Summer Monsoon (EASM) precipitation, and so Yangtze delta sediments may preserve information about the frequency and magnitude of EASM precipitation. These flood/drought cycles of the EASM directly affect...... the living standards of East Asian population. However, despite its importance, little chronological control is available for the Yangtze Delta sediments; because biogenic carbonate only occurs sporadically, it has proved the difficulty to discuss sedimentation mechanisms and rates in any detail. In 2013 two...... sediment cores (YD13-G3 and H1) were taken from the Yangtze subaqueous delta to investigate precipitation history. In this study, we investigate the potential of quartz OSL dating of the fine silt fraction (fine-grained quartz; 4-11 μm) from these cores to estimate the depositional age of the sediments. We...

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)

Energy dependence measurement of small-type optically stimulated luminescence (OSL) dosimeter by means of characteristic X-rays induced with general diagnostic X-ray equipment.

Science.gov (United States)

Takegami, Kazuki; Hayashi, Hiroaki; Okino, Hiroki; Kimoto, Natsumi; Maehata, Itsumi; Kanazawa, Yuki; Okazaki, Tohru; Hashizume, Takuya; Kobayashi, Ikuo

2016-01-01

For X-ray inspections by way of general X-ray equipment, it is important to measure an entrance-skin dose. Recently, a small optically stimulated luminescence (OSL) dosimeter was made commercially available by Landauer, Inc. The dosimeter does not interfere with the medical images; therefore, it is expected to be a convenient detector for measuring personal exposure doses. In an actual clinical situation, it is assumed that X-rays of different energies will be detected by a dosimeter. For evaluation of the exposure dose measured by a dosimeter, it is necessary to know the energy dependence of the dosimeter. Our aim in this study was to measure the energy dependence of the OSL dosimeter experimentally in the diagnostic X-ray region. Metal samples weighing several grams were irradiated and, in this way, characteristic X-rays having energies ranging from 8 to 85 keV were generated. Using these mono-energetic X-rays, the dosimeter was irradiated. Simultaneously, the fluence of the X-rays was determined with a CdTe detector. The energy-dependent efficiency of the dosimeter was derived from the measured value of the dosimeter and the fluence. Moreover, the energy-dependent efficiency was calculated by Monte-Carlo simulation. The efficiency obtained in the experiment was in good agreement with that of the simulation. In conclusion, our proposed method, in which characteristic X-rays are used, is valuable for measurement of the energy dependence of a small OSL dosimeter in the diagnostic X-ray region.

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 %

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.

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

International Nuclear Information System (INIS)

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

2011-01-01

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

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

Performance of CVD diamond as an optically and thermally stimulated luminescence dosemeter

International Nuclear Information System (INIS)

Preciado-Flores, S.; Schreck, M.; Melendrez, R.; Chernov, V.; Bernal, R.; Cruz-Vazquez, C.; Cruz-Zaragoza, E.; Barboza-Flores, M.

2006-01-01

Diamond is a material with extreme physical properties. Its radiation hardness, chemical inertness and tissue equivalence qualify it as an ideal material for radiation dosimetry. In the present work, the optically stimulated luminescence (OSL) and thermoluminescence (TL) characteristics of a 10 μm thick CVD diamond (polycrystalline diamond films prepared by chemical vapor deposition) film were studied in order to test its performance as a beta radiation dosemeter. The TL response is composed of four main TL glow peaks; two of these are in the range of 150-200 deg. C and two additional peaks in the 250-400 deg. C temperature range. The integrated TL as a function of radiation dose is linear up to 100 Gy and increases with increasing dose exposure. The dose dependence of the integrated OSL exhibits a similar behavior. The observed OSL/TL behavior for the CVD diamond film clearly demonstrate its capability for applications in radiation dosimetry with special relevance in medical dosimetry owing to the diamond's intrinsic material properties. (authors)

Testing the accuracy of a Bayesian central-dose model for single-grain OSL, using known-age samples

DEFF Research Database (Denmark)

Guerin, Guillaume; Combès, Benoit; Lahaye, Christelle

2015-01-01

on multi-grain OSL age estimates, these samples are presumed to have been both well-bleached at burial, and unaffected by mixing after deposition. Two ways of estimating single-grain ages are then compared: the standard approach on the one hand, consisting of applying the Central Age Model to De values...... for well-bleached samples; (ii) dose recovery experiments do not seem to be a very reliable tool to estimate the accuracy of a SAR measurement protocol for age determination....

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)

Evaluation of personal dosemeters and comparative measurements performed by PTB in the years 1979 through 1984. Pt. 1

International Nuclear Information System (INIS)

Boehm, J.; Buchholz, G.

1986-01-01

Comparison measurements of the official individual dosemeters performed in the PTB from 1979 to 1984 are described. Also a number of other, unofficial individual dosemeters participated. The performance of the comparison measurements and the types of the individual dosemeters are described. Tables show the values measured with the film dosemeters, with film and TLD dosemeters, and TLD dosemeters as well as dosimetric probes for whole-body and partial body dose measurement. (DG) [de

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

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

International Nuclear Information System (INIS)

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

2001-01-01

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

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.

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)

De determination for young samples using the standardised OSL response of coarse-grain quartz

International Nuclear Information System (INIS)

Burbidge, C.I.; Duller, G.A.T.; Roberts, H.M.

2006-01-01

It has recently been shown that it is possible to construct standardised curves of the sensitivity corrected growth in optically stimulated luminescence (OSL) with exposure to ionising radiation, and that they may be used in the dating of quartz and polymineral samples. Standardised growth curves are particularly advantageous where measurement time is limited, as once they have been defined, only the natural signal and the response to a subsequent test dose are required in order to determine the equivalent dose of a sub-sample. The present study is concerned with the application of the standardised growth curve approach to OSL dating of Holocene age samples. Systematic changes in the shape of the standardised growth curve of coarse-grain quartz are identified as the size of the test dose is varied, because of non-proportionality between the test dose and the luminescence test response. The effect is characterised by fitting the change in gradient of the standardised growth curve as test dose is varied. An equation is defined to describe standardised growth as a function of regenerative dose and test dose. Regenerative dose responses of other samples in this study are treated as unknowns and recovered through different growth curves to compare precision and accuracy of various methods of D e determination. The standardised growth curve is found to yield similar precision to conventional fits of single aliquot regenerative data, but slightly poorer accuracy. The standardised growth curve approach was refined by incorporating the measurement of one regenerative response for each aliquot as well as its natural signal. Measurements of this additional data point for aliquots of 22 samples were used to adjust the standardised growth equation, improving its accuracy. The incorporation of this additional data point also indicated a systematic uncertainty of 2.4% in the estimates of D e

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

Application of pulsed OSL to the separation of the luminescence components from a mixed quartz/feldspar sample

DEFF Research Database (Denmark)

Denby, Phil M.; Bøtter-Jensen, L.; Murray, A.S.

2006-01-01

with a feldspar signal. We have developed instrumentation for the study of high-speed pulse stimulated OSL. Our system uses the standard blue/IR LED stimulation unit of a Riso reader (allowing stimulation pulses down to 1-2 mu s duration) and can thus be applied to the routine analysis of samples. Using...... that counts are only accumulated during a windowed period, reduces the feldspar signal to 1.6% of its original value relative to that of the quartz. (c) 2006 Elsevier Ltd. All rights reserved....

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

Thyroid dose measurement in patients undergoing to digital orthopantomography using optical stimulation dosimeters

International Nuclear Information System (INIS)

Gutierrez M, J. G.; Lopez V, A.; Rivera M, T.; Avalos P, L. Y.

2016-10-01

In this paper we present the study of the thyroid equivalent dose in 300 patients undergoing to digital orthopantomography for dental treatment purposes using optical stimulation dosimeters (OSL) as in-vivo dosimeters, in order to verify if this is within acceptable parameters to prevent stochastic risks and to evaluate the possible risks caused by the technique used for this type of study (66 kv, 5 m A, 14.1 s). Three OSL dosimeters were used per patient, which were placed by the physician on the skin above the thyroid gland (using anatomical references and palpation); the information of the patients was divided by neck size and sex, finding a slight increase in the equivalent dose for female and small size patient, this combination being the group that was submitted to a higher dose. The results obtained were compared with similar studies performed on anthropomorphic mannequins with TLD dosimeters obtaining lower results. The equivalent dose found even though is below the threshold stochastic damage must be motorized for radiological protection and registration purposes. (Author)

Thyroid dose measurement in patients undergoing to digital orthopantomography using optical stimulation dosimeters; Medicion de dosis en tiroides en pacientes sometidos a ortopantografia digital utilizando dosimetros de estimulacion optica

Energy Technology Data Exchange (ETDEWEB)

Gutierrez M, J. G.; Lopez V, A.; Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Legaria, Calz. Legaria 694, Col. Irrigacion, 11500 Ciudad de Mexico (Mexico); Avalos P, L. Y., E-mail: jggm25@yahoo.com.mx [UNAM, Facultad de Odontologia, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico)

2016-10-15

In this paper we present the study of the thyroid equivalent dose in 300 patients undergoing to digital orthopantomography for dental treatment purposes using optical stimulation dosimeters (OSL) as in-vivo dosimeters, in order to verify if this is within acceptable parameters to prevent stochastic risks and to evaluate the possible risks caused by the technique used for this type of study (66 kv, 5 m A, 14.1 s). Three OSL dosimeters were used per patient, which were placed by the physician on the skin above the thyroid gland (using anatomical references and palpation); the information of the patients was divided by neck size and sex, finding a slight increase in the equivalent dose for female and small size patient, this combination being the group that was submitted to a higher dose. The results obtained were compared with similar studies performed on anthropomorphic mannequins with TLD dosimeters obtaining lower results. The equivalent dose found even though is below the threshold stochastic damage must be motorized for radiological protection and registration purposes. (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)

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)

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

International Nuclear Information System (INIS)

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

2002-01-01

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

A novel KMgPO{sub 4}:Tb{sup 3+}(KMPT) phosphor for radiation dosimetry

Energy Technology Data Exchange (ETDEWEB)

Palan, C.B., E-mail: chetanpalan27@gmail.com [Department of Physics, Sant Gadge Baba Amravati University, Amravati 44602 (India); Bajaj, N.S. [Department of Physics, Toshniwal ACS College, Sengaon, Hingoli 431542 (India); Soni, A. [Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400094 (India); Omanwar, S.K. [Department of Physics, Sant Gadge Baba Amravati University, Amravati 44602 (India)

2016-08-15

The polycrystalline sample of KMgPO{sub 4}:Tb{sup 3+}(KMPT) phosphor was successfully synthesized by using solid state method. The X-ray powder diffraction, photoluminescence (PL) emission and excitation spectra, thermoluminescence (TL) and optically stimulated luminescence (OSL) were thoroughly measured. The PL spectra of as-prepared KMPT phosphor showed characteristic blue-green emission, when excited by 226 nm under UV excitation. The optimum PL intensity was observed at 0.01 mol concentration of Tb{sup 3+}ions and this phosphor used for remaining studies. The TL glow curve of KMPT phosphor consist two characterized peaks, which were deconvoluted and the kinetic parameters i.e. trap depth or activation energy, order of kinetic and frequency factor determined by using peak shape method. TL sensitivity of KMPT phosphors was found to be 10% than that of TL sensitivity of TLD-500 phosphor. The OSL sensitivity of KMPT was 0.92 times than OSL sensitivity of α-Al{sub 2}O{sub 3}:C phosphor. The OSL decay curve KMPT phosphor consist of three component having photoionization cross sections were found to be 0.26548×10{sup −17}, 0.220×10{sup −17}, 2.92×10{sup −17} cm{sup 2}. The KMPT phosphor showed linear dose response in range 100–6000 mGy and fading of KMPT phosphor was found to be 31% in 15 days. The Minimum detectable dose (MDD) was found to be 0.39 mGy with corresponding 3σ back ground. The phosphor shows good dosimetry properties such as sensitivity, dose response, MDD, Fading.

Dating recent floodplain sediments in the Hawkesbury-Nepean River system, eastern Australia using single-grain quartz OSL

DEFF Research Database (Denmark)

Sim, Anna K.; Thomsen, Kristina Jørkov; Murray, K.J.

2014-01-01

Two fluvial sediment cores taken from a floodplain of the Hawkesbury-Nepean River system in the Sydney region, eastern Australia are dated using Optically Stimulated Luminescence (OSL) to provide a reliable chronology essential for the management and planning of water resources. Nine charcoal 14C...... in an average apparent age overestimation of ~200 years, which is significant for these samples, but negligible for sediments older than a few thousand years. The intention is that the chronology obtained in this study will be used in conjunction with a proxy flood record, derived from floodplain sediments...

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)

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

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

The quality of dental radiography in the Czech Republic - Results of a TLD and film postal audit

International Nuclear Information System (INIS)

Novak, L.

2006-01-01

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

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)

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

International Nuclear Information System (INIS)

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

1999-01-01

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

Thermoluminescence characterisation of chemical vapour deposited diamond films

CERN Document Server

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

2002-01-01

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

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)

Luminescence dating of Pleistocene alluvial sediments affected by the Alhama de Murcia fault (eastern Betics, Spain) – a comparison between OSL, IRSL and post-IRIRSL ages

DEFF Research Database (Denmark)

Sohbati, Reza; Murray, Andrew S.; Buylaert, Jan-Pieter

2012-01-01

The ages of nine alluvial units, identified by the integration of data obtained from five trenches at the southern termination of the Alhama de Murcia Fault (AMF) (eastern Betics, Spain), are constrained using luminescence dating based on the Optically Stimulated Luminescence (OSL) from quartz...

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)

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)

Preliminary results of chronostratigraphic field work, OSL-dating and morphogenetic reconstruction of an alluvial apron at Alborz southern foothill, Damghan basin, Iran

Science.gov (United States)

Büdel, Christian; Fuchs, Markus; Majid Padashi, Seyed; Baumhauer, Roland

2014-05-01

Here we present preliminary results of a chronostratigraphic study of an alluvial fan in the Damghan Basin, northern Iran. The basin sediments date back to the Mio- and Pliocene and therefore represent the starting point of alluvial fan aggradation. Today, the still active alluvial fans prograde from the Albors Mountain ranges and sit on the older sediment bodies. In this study, our focus is on the late Pleistocene to Holocene alluvial fan sedimentation history. The upper stratigraphy of the alluvial fans and intercalated lake deposits is characterized by six individual layers of gravels and fines, representing six different stratigraphic units. These units are described and classified by detailed geomorphological and stratigraphic mapping. To establish an alluvial fan chronology, six profiles were sampled for OSL dating. As expected, due to the high-energy transport system of alluvial fan aggradation in semi-desert environments, OSL dating of these sediments is challenging due to the problem of insufficient bleaching. Consequently, most of the samples are interpreted as maximum ages. However, the measurements show a consistent internal age structure and the overall OSL-based chronology is in agreement with the age model derived from our geomorphological analysis. As a first interpretation, based on surveyed geomorphological features and chronological analysis, we could identify seven morphodynamic phases, leading to a genetic model of alluvial fan aggradation. The oldest Pleistocene age estimate is derived from a former lake terrace. The following ages represent ongoing lake sediment deposition and the development of a proximal and mid-fan gravel cover. After the youngest lake deposits were accumulated within the Holocene, the lake starts to retreat and small alluvial fans are filling up the former lake bottom. This last sedimentation phase can be divided in at least two sub-phases, probably coupled to a lateral shifting of the active depositional lobe and to the

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)

Radiation dose during tomography of the petrous bone. Experimental investigations with film dosimetry on an Alderson phantom

Energy Technology Data Exchange (ETDEWEB)

Grehn, S.

1988-06-01

Using filmdosimetry and an Alderson skull phantom, the iso-dose distribution during tomography of the petrous bone was investigated. We were particularly concerned with the radiation dose to the lens of the eye, the critical organ in the skull, and to the inner ear, using different types of examination and various positions of the skull. The choice of suitable film material and standardisation against TLD measurements is crucial for the accuracy of film dosimetry, allowing for correction of film blackening in relation to varying energies. Tomography of the petrous bone in the prone position produced a reduction in radiation dose to the eye to only 1 to 4% of the dose incident on the occiput. In this way, and using high definition screen and grinds, it is possible to obtain optimal tomographic images despite drastic reduction of the scattered radiation to the eye. Radiation dose to the inner ear is greatly below any significant somatic dose, irrespective of projection or technique. Special measures to reduce radiation to the inner ear are neither effective nor sensible.

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)

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.

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)

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

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

International Nuclear Information System (INIS)

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

2003-01-01

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

Skin dose for head and neck cancer patients treated with intensity-modulated radiation therapy(IMRT)

Science.gov (United States)

Fu, Hsiao-Ju; Li, Chi-Wei; Tsai, Wei-Ta; Chang, Chih-Chia; Tsang, Yuk-Wah

2017-11-01

The reliability of thermoluminescent dosimeters (ultrathin TLD) and ISP Gafchromic EBT2 film to measure the surface dose in phantom and the skin dose in head-and-neck patients treated with intensity-modulated radiation therapy technique(IMRT) is the research focus. Seven-field treatment plans with prescribed dose of 180 cGy were performed on Eclipse treatment planning system which utilized pencil beam calculation algorithm(PBC). In calibration tests, the variance coefficient of the ultrathin TLDs were within 3%. The points on the calibration curve of the Gafchromic film was within 1% variation. Five measurements were taken on phantom using ultrathin TLD and EBT2 film respectively. The measured mean surface doses between ultrathin TLD or EBT2 film were within 5% deviation. Skin doses of 6 patients were measured for initial 5 fractions and the mean dose per-fraction was calculated. If the extrapolated doses for 30 fractions were below 4000 cGy, the skin reaction grading observed according to Radiation Therapy Oncology Group (RTOG) was either grade 1 or grade 2. If surface dose exceeded 5000 cGy in 32 fractions, then grade 3 skin reactions were observed.

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.

Angular dependence of the nanoDot OSL dosimeter

International Nuclear Information System (INIS)

Kerns, James R.; Kry, Stephen F.; Sahoo, Narayan; Followill, David S.; Ibbott, Geoffrey S.

2011-01-01

Purpose: Optically stimulated luminescent detectors (OSLDs) are quickly gaining popularity as passive dosimeters, with applications in medicine for linac output calibration verification, brachytherapy source verification, treatment plan quality assurance, and clinical dose measurements. With such wide applications, these dosimeters must be characterized for numerous factors affecting their response. The most abundant commercial OSLD is the InLight/OSL system from Landauer, Inc. The purpose of this study was to examine the angular dependence of the nanoDot dosimeter, which is part of the InLight system. Methods: Relative dosimeter response data were taken at several angles in 6 and 18 MV photon beams, as well as a clinical proton beam. These measurements were done within a phantom at a depth beyond the build-up region. To verify the observed angular dependence, additional measurements were conducted as well as Monte Carlo simulations in MCNPX. Results: When irradiated with the incident photon beams parallel to the plane of the dosimeter, the nanoDot response was 4% lower at 6 MV and 3% lower at 18 MV than the response when irradiated with the incident beam normal to the plane of the dosimeter. Monte Carlo simulations at 6 MV showed similar results to the experimental values. Examination of the results in Monte Carlo suggests the cause as partial volume irradiation. In a clinical proton beam, no angular dependence was found. Conclusions: A nontrivial angular response of this OSLD was observed in photon beams. This factor may need to be accounted for when evaluating doses from photon beams incident from a variety of directions.

A compact design for monochromatic OSL measurements in the wavelength range 380-1020 NM

DEFF Research Database (Denmark)

Bøtter-Jensen, L.; Poolton, N.R.J.; Willumsen, F.

1994-01-01

automated Riso TL/OSL dating apparatus, thus allowing for either routine scanning or more detailed thermo-optical investigations. The high throughput efficiency of the unit means that the existing 75 W tungsten-halogen lamp can be directly used for such measurements on both quartz and feldspar samples......The development and performance of a compact module is described that allows for the monochromatic illumination of samples in the wavelength range 380-1020 nm, enabling the measurement of energy-resolved optically stimulated luminescence. The unit is designed to couple directly to the existing....... The design allows for rapid spectral scanning with a choice of resolution of anywhere between 10 and 80 nm: stray light levels are less than 0.01%. The unit can equally be used for recording wavelength-resolved emission spectra, whether photo-excited or thermally stimulated; the capabilities of the system...

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)

Estimation of identification limit for a small-type OSL dosimeter on the medical images by measurement of X-ray spectra

OpenAIRE

Takegami, Kazuki ; Hayashi, Hiroaki; Okino, Hiroki; Kimoto, Natsumi ; Maehata, Itsumi ; Kanazawa, Yuki ; Okazaki, Tohru ; Hashizume, Takuya ; Kobayashi, Ikuo 

2016-01-01

Our aim in this study is to derive an identification limit on a dosimeter for not disturbing a medical image when patients wear a small-type optically stimulated luminescence (OSL) dosimeter on their bodies during X-ray diagnostic imaging. For evaluation of the detection limit based on an analysis of X-ray spectra, we propose a new quantitative identification method. We performed experiments for which we used diagnostic X-ray equipment, a soft-tissue-equivalent phantom (1–20 cm), and a CdTe X...

Measurement of neutron dose and spectra at light-water reactors

International Nuclear Information System (INIS)

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

1982-08-01

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

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.

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)

A low-cost personal dosemeter based on optically stimulated luminescence (OSL) of common household salt (NaCl)

International Nuclear Information System (INIS)

Ekendahl, Daniela; Bulánek, Boris; Judas, Libor

2016-01-01

Salt represents a radiation sensitive material that can be used for dosimetry. The objective of this experimental study was to test a low-cost salt dosemeter that was designed for personnel that are not radiation workers, but can operate in low probability events resulting in a serious external radiation exposure. The dosemeter is based on use of optically stimulated luminescence (OSL) of a common household salt. Attention was concentrated on its energy and angular responses. The dosemeter was fixed to the ICRU slab phantom and irradiated by photons of reference radiation qualities (ISO 4037-1) with mean energies between 33 and 1250 keV. Angular response was investigated for angles of incidence from 0° to 80° for radiation qualities of N-150 (∼118 keV) and S-Cs (∼662 keV). Single-Aliquot Regenerative-dose analytical protocol was employed for dose reconstruction. The results were evaluated with respect to H_p(10) measurement. The salt dosemeter can provide reliable or reasonably conservative H_p(10) estimates in radiation fields where photon energies > 100 keV predominate, radiation incidence angles are from 0° to 80° and also for rotational geometry. Furthermore, a personal dose reconstruction trial was demonstrated. Relative deviation between the measured and reference H_p(10) values was 5.5%. A practical disadvantage of the method is the more demanding analytical protocol. - Highlights: • Common salt has a considerable potential for dosimetry based on use of OSL. • A simple salt personal dosemeter was designed and tested. • Photon energy and angular responses were satisfactory for purposes of accidental dosimetry. • Dose reconstruction trial proved the potential for reliable estimate of personal doses.

The dose dependency of the over-dispersion of quartz OSL single grain dose distributions

DEFF Research Database (Denmark)

Thomsen, Kristina Jørkov; Murray, Andrew S.; Jain, Mayank

2012-01-01

The use of single grain quartz OSL dating has become widespread over the past decade, particularly with application to samples likely to have been incompletely bleached before burial. By reducing the aliquot size to a single grain the probability of identifying the grain population most likely...... to have been well-bleached at deposition is maximised and thus the accuracy with which the equivalent dose can be determined is – at least in principle – improved. However, analysis of single grain dose distributions requires knowledge of the dispersion of the well-bleached part of the dose distribution....... This can be estimated by measurement of a suitable analogue, e.g. a well-bleached aeolian sample, but this requires such an analogue to be available, and in addition the assumptions that the sample is in fact a) well-bleached, and b) has a similar dose rate heterogeneity to the fossil deposit. Finally...

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

Application of artificial neural network for development of an algorithm for TLD badge system in the mixed field dosimetry of X and gamma radiation in terms of Hp(10)

International Nuclear Information System (INIS)

Srivastava, K.; Bakshi, A.K.; Geetha, V.; Kher, R.K.; Dhar, V.K.

2005-01-01

ICRU has introduced new operational quantities for individual monitoring. Therefore it is required to develop an algorithm that gives direct response of the TLD badge in terms of the operational quantities. For this purpose and also to improve the precision in the mixed fields dosimetry, two methods were studied i)- analytical method by developing an algorithm based on of higher order polynomial fit of the data points for known delivered doses and ii) use of Artificial Neural Network (ANN). Study on the response of the TLD badge system based on CaSO 4 : Dy Teflon TLD discs in the mixed fields of X and gamma radiation in terms of operational quantity Hp(10) was carried out using the prevalent algorithm, algorithm developed using higher order polynomial and neural network predicted algorithm for different proportion of dose delivered by X and gamma radiations. It was found that the uncertainties in the dose response for few fields are beyond the acceptable limit for prevalent algorithm and within the acceptable limit for other two algorithms. Algorithm based on ANN gives higher precision in the mixed field of two radiations compared to other two algorithms. (author)

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)

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