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Sample records for formate epr dosimetry

  1. EPR Dosimetry - Present and Future

    Energy Technology Data Exchange (ETDEWEB)

    Regulla, D.F. [GSF - National Research Centre for Environment and Health, Institute of Radiation Protection, 85764 Neuherberg (Germany)

    1999-07-01

    In the past, IAEA has played a central role in stipulating research and development in EPR high-dose standardisation as well as in coordinating and organising international dose intercomparison programs, within the Member States of the United Nations from the mid-seventies till today. The future tasks of EPR dosimetry seem to tend towards different subjects such as bio markers, biological radiation effects, post-accident dose reconstruction in the environment, and retrospective human dosimetry. The latter may be considered a promising tool for epidemiology on the way to re-define radiation risk of man for chronicle radiation exposures, based on e.g. South Ural civil population and radiation workers. There are on-going international activities in the field of standardising high-level dosimetry by the American Standards on Testing and Materials (Astm), and by the International Organisation of Standards (ISO). The International Commission on Radiation Units and Measurements (ICRU) is considering the establishment of relevant recommendations concerning industrial radiation processing, but also human dose reconstruction. (Author)

  2. Protocol for emergency EPR dosimetry in fingernails

    OpenAIRE

    Trompier, F; Kornak, L.; Calas, C.; Romanyukha, A.; LeBlanc, B.; Mitchell, C. A.; Swartz, H M; Clairand, I.

    2007-01-01

    There is an increased need for after-the-fact dosimetry because of the high risk of radiation exposures due to terrorism or accidents. In case of such an event, a method is needed to make measurements of dose in a large number of individuals rapidly and with sufficient accuracy to facilitate effective medical triage. Dosimetry based on EPR measurements of fingernails potentially could be an effective tool for this purpose. This paper presents the first operational protocols for EPR fingernail...

  3. Protocol for emergency EPR dosimetry in fingernails.

    Science.gov (United States)

    Trompier, F; Kornak, L; Calas, C; Romanyukha, A; Leblanc, B; Mitchell, C A; Swartz, H M; Clairand, I

    2007-08-01

    There is an increased need for after-the-fact dosimetry because of the high risk of radiation exposures due to terrorism or accidents. In case of such an event, a method is needed to make measurements of dose in a large number of individuals rapidly and with sufficient accuracy to facilitate effective medical triage. Dosimetry based on EPR measurements of fingernails potentially could be an effective tool for this purpose. This paper presents the first operational protocols for EPR fingernail dosimetry, including guidelines for collection and storage of samples, parameters for EPR measurements, and the method of dose assessment. In a blinded test of this protocol application was carried out on nails freshly sampled and irradiated to 4 and 20 Gy; this protocol gave dose estimates with an error of less than 30%.

  4. EPR-dosimetry with carious teeth

    Energy Technology Data Exchange (ETDEWEB)

    Sholom, S.V. E-mail: sholom@leed1.kiev.ua; Haskell, E.H.; Hayes, R.B.; Chumak, V.V.; Kenner, G.H

    2000-12-15

    The effect of caries in EPR dosimetry of tooth enamel (in the dose range of 0-1 Gy) was investigated. The enamel of each tooth was divided into carious, non-carious and intermediate portions. The EPR signals of enamel at g=2.0018 (dosimetric) and g=2.0045 (native) were examined. The intensity of the dosimetric signal was the same for all three portions, while that of the native signal was higher for carious portions than for non-carious and intermediate portions. Reconstruction of the laboratory applied doses was done using all portions. Reasonable correlation between nominal and reconstructed doses was found in most cases. The effect of alkali treatment on the native and dosimetric signals of enamel was also tested. Reduction of the native signal intensity, particularly in the carious portions, was found to be the only significant effect. This resulted in a slight improvement in the accuracy of the reconstructed doses.

  5. Methodological aspects of EPR dosimetry with teeth

    Energy Technology Data Exchange (ETDEWEB)

    Sholom, S.; Chumak, V. [Scientific Center for Radiation Medicine, Kiev (Ukraine)

    2001-07-01

    EPR dosimetry with tooth enamel is known today as one of the most reliable and accurate methods of retrospective dosimetry. In the present study a comprehensive analysis of influence of the major confounding factors (solar UV exposure and dental X-ray diagnostic procedures) on the accuracy of accidental dose reconstruction is given. In this analysis, the facts known from literature as well as own authors' results were considered. Among the latter it is worth to mention study of doses in enamel caused by X-ray diagnostic procedures as well as investigation of dose profiles in front teeth, which are most affected to solar radiation. As a main result, the variant of dosimetric technique is proposed. It comprises the optimal combination of strongest sides of existing techniques which allows to conduct routine reconstruction of accidental doses as low as few tens of mGy with errors of the same order of magnitude. The proposed technique is primarily destined for dosimetry of Chernobyl liquidators, but could be used for reconstruction of doses of other over-exposed categories. (orig.)

  6. EPR tooth dosimetry of SNTS area inhabitants

    Energy Technology Data Exchange (ETDEWEB)

    Sholom, Sergey [Scientific Center for Radiation Medicine, Melnikova str., 53, Kiev (Ukraine); Desrosiers, Marc [Ionizing Radiation Division, National Institute of Standards and Technology, Gaithersburg, MD (United States); Bouville, Andre; Luckyanov, Nicholas [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, 6120 Executive Boulevard, Bethesda, MD (United States); Chumak, Vadim [Scientific Center for Radiation Medicine, Melnikova str., 53, Kiev (Ukraine); Simon, Steven L. [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, 6120 Executive Boulevard, Bethesda, MD (United States)], E-mail: ssimon@mail.nih.gov

    2007-07-15

    The determination of external dose to teeth of inhabitants of settlements near the Semipalatinsk Nuclear Test Site (SNTS) was conducted using the EPR dosimetry technique to assess radiation doses associated with exposure to radioactive fallout from the test site. In this study, tooth doses have been reconstructed for 103 persons with all studied teeth having been formed before the first nuclear test in 1949. Doses above those received from natural background radiation, termed 'accident doses', were found to lie in the range from zero to approximately 2 Gy, with one exception, a dose for one person from Semipalatinsk city was approximately 9 Gy. The variability of reconstructed doses within each of the settlements demonstrated heterogeneity of the deposited fallout as well as variations in lifestyle. The village mean external gamma doses for residents of nine settlements were in the range from a few tens of mGy to approximately 100 mGy.

  7. Software for evaluation of EPR-dosimetry performance.

    Science.gov (United States)

    Shishkina, E A; Timofeev, Yu S; Ivanov, D V

    2014-06-01

    Electron paramagnetic resonance (EPR) with tooth enamel is a method extensively used for retrospective external dosimetry. Different research groups apply different equipment, sample preparation procedures and spectrum processing algorithms for EPR dosimetry. A uniform algorithm for description and comparison of performances was designed and implemented in a new computer code. The aim of the paper is to introduce the new software 'EPR-dosimetry performance'. The computer code is a user-friendly tool for providing a full description of method-specific capabilities of EPR tooth dosimetry, from metrological characteristics to practical limitations in applications. The software designed for scientists and engineers has several applications, including support of method calibration by evaluation of calibration parameters, evaluation of critical value and detection limit for registration of radiation-induced signal amplitude, estimation of critical value and detection limit for dose evaluation, estimation of minimal detectable value for anthropogenic dose assessment and description of method uncertainty.

  8. Identification and dosimetry of irradiated walnuts (Juglans regia) using EPR

    Science.gov (United States)

    Maghraby, A.; Salama, E.; Sami, A.; Mansour, A.; El-Sayed, M.

    2012-03-01

    Electron paramagnetic resonance (EPR) is an easy, fast, and reliable tool for identification of irradiated food. Untreated nuts may encounter hazards of carrying several pathogens or microbial contamination; walnuts are of specific importance due to their nutritional and medicinal values, and hence walnut processing via gamma irradiation is a necessary step. EPR was employed for the identification and dosimetry of Cs-137 gamma-irradiated walnuts (shells and kernels). Several important parameters were studied, such as spectral features, microwave power dependence of signal intensities, and short- and long-term time dependences. Responses of walnut shells and kernels to different radiation doses in the range 0-10 kGy were investigated. Results confirmed that EPR is a suitable tool for the identification and dosimetry of irradiated walnuts using either their shells or only kernels.

  9. EPR/PTFE dosimetry for test reactor environments

    Energy Technology Data Exchange (ETDEWEB)

    Vehar, D.W.; Griffin, P.J.; Quirk, T.J. [Sandia National Laboratories, Albuquerque, NM 87185-1146 (United States)

    2011-07-01

    The use of Electron Paramagnetic Resonance (EPR) spectroscopy with materials such as alanine is well established as a technique for measurement of ionizing radiation absorbed dose in photon and electron fields such as Co-60, high-energy bremsstrahlung and electron-beam fields [1]. In fact, EPR/Alanine dosimetry has become a routine transfer standard for national standards bodies such as NIST and NPL. In 1992 the Radiation Metrology Laboratory (RML) at Sandia National Laboratories implemented EPR/Alanine capabilities for use in routine and calibration activities at its Co-60 and pulsed-power facilities. At that time it also investigated the usefulness of the system for measurement of absorbed dose in the mixed neutron/photon environments of reactors such as the Sandia Pulsed Reactor and the Annular Core Research Reactor used for hardness testing of electronics. The RML concluded that the neutron response of alanine was a sufficiently high fraction of the overall dosimeter response that the resulting uncertainties in the photon dose would be unacceptably large for silicon-device testing. However, it also suggested that non-hydrogenous materials such as polytetrafluoroethylene (PTFE) would exhibit smaller neutron response and might be useful in mixed environments. Preliminary research with PTFE in photon environments indicated considerable promise, but further development was not pursued at that time. Because of renewed interest in absorbed dose measurements that could better define the individual contributions of photon and neutron components to the overall dose delivered to a test object, the RML has re-initiated the development of an EPR/PTFE dosimetry system. This effort consists of three stages: 1) Identification of PTFE materials that may be suitable for dosimetry applications. It was speculated that the inconsistency of EPR signatures in the earlier samples may have been due to variability in PTFE manufacturing processes. 2) Characterization of dosimetry in

  10. Retrospective dosimetry using EPR and TL techniques: a status report

    Energy Technology Data Exchange (ETDEWEB)

    Haskell, E.H.

    1996-12-31

    Methods of retrospective dosimetry, including luminescence and electron paramagnetic resonance spectroscopy (EPR), rely on measurement of accident dose absorbed by naturally occurring materials - ceramics in the case of both thermoluminescence (TL) and optically stimulated luminescence (OSL) and organic materials and bio- minerals in the case of EPR. Each of these methods relies on measurement of radiation defects resulting from accidental exposure. Since defects also result from natural sources of radiation over the lifetime of a sample, analysis is usually restricted to materials for which the natural dose may be determined and subtracted from the measured cumulative dose. Luminescence dating techniques rely heavily on an accurate assessment of cumulative dose from natural radiation sources, and dating research has provided us with the bulk of our knowledge in this area. Virtually all of the work on natural dose determination can be directly applied to retrospective techniques. With EPR techniques the cumulative dose from diagnostic x- rays is also of importance.

  11. Preliminary study for precision dosimetry using electron paramagnetic resonance (EPR) in radiotherapy applications

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

    EPR (Electron paramagnetic resonance) dosimetry for radiotherapy dose range (1-10 Gy) is still being established.Alanine is an important material for EPR dosimetry because in terms of density and radiation absorption properties, it is water equivalent. High repeatability and high reproducibility of alanine spectrum measurement makes it possible to estimate the irradiation dose accurately. This baseline study has been carried out to establish precision EPR dosimetry in therapeutic photon range. For that purpose, an EPR dosimetry system has been setup and repeatability as well as reproducibility of measurements using alanine dosimeter have been evaluated. Effect of anisotropy of alanine dosimeter in spectrometer cavity has also been observed. EPR dosimetry system is set up at KRISS. It is found that reproducibility of the system at therapeutic photon range is 1.5 % - 6.6 %.

  12. Medical reference dosimetry using EPR measurements of alanine

    DEFF Research Database (Denmark)

    Helt-Hansen, Jakob; Rosendal, F.; Kofoed, I.M.

    2009-01-01

    Background. Electron spin resonance (EPR) is used to determine the absorbed dose of alanine dosimeters exposed to clinical photon beams in a solid-water phantom. Alanine is potentially suitable for medical reference dosimetry, because of its near water equivalence over a wide energy spectrum, low...... on scaling of known spectra was developed to extract the alanine signal. Results. The dose accuracy, including calibration uncertainty, is less than 2% (k=1) above 4 Gy (n=4). The measurement uncertainty is fairly constant in absolute terms (30 mGy) and the relative uncertainty therefore rises for dose...... measurements below 4 Gy. Typical reproducibility is 1% (k=1) above 10 Gy and 2% between 4 and 10 Gy. Below 4 Gy the uncertainty is higher. A depth dose curve measurement was performed in a solid-water phantom irradiated to a dose of 20 Gy at the maximum dose point (dmax) in 6 and 18 MV photon beams...

  13. EPR dosimetry of radiation background in the Urals region

    Energy Technology Data Exchange (ETDEWEB)

    Shishkina, E.A.; Degteva, M.O.; Shved, V.A. [Urals Research Center for Radiation Medicine, 48-A Vorovsky, Chelyabinsk 454076 (Russian Federation); Fattibene, P.; Onori, S. [Istituto Superiore di Sanita and Istituto Nazionale di Fisica Nucleare (Italy); Wieser, A. [GSF, Forschungszentrum fuer Umwelt und Gesundheit, Ingolstaedter Landstr (Germany); Ivanov, D.V.; Bayankin, S.N. [Institute of Metal Physics, Russian Academy of Sciences (Russian Federation); Knyazev, V.A.; Vasilenko, E.I.; Gorelov, M. [ZAO, Closed Corporation ' Company GEOSPETSECOLOGIA' (Russian Federation)

    2006-07-01

    Method of Electron Paramagnetic Resonance is extensively applied to individual retrospective dosimetry. The background dose is unavoidable component of cumulative absorbed dose in the tooth enamel accumulated during the lifetime of donor. Estimation of incidental radiation dose using tooth enamel needs in extraction of background dose. Moreover, the variation of background doses in the population is a limited factor for reliable detection of additional irradiation especially for low dose level. Therefore the accurate knowledge of the natural background radiation dose is a critical element of EPR studies of exposed populations. In the Urals region the method applies for such two large cohorts as the workers of Mayak (Ozersk citizens) and Techa River riverside inhabitants (rural population). Current study aimed to investigate the Urals radiation background detected by EPR spectrometry. For this aim two group of unexposed Urals residents were separated, viz: citizens of Ozersk and rural inhabitants of Chelyabinsk region. Comparison of two investigated territories has demonstrated that from the point of view of radiation background it is impossible to assume the Urals population as uniform. The reliable difference between the urban and rural residents has been found. The average background doses of Ozersk donors is in average 50 mGy higher than those detected for rural residents. The individual variability of background doses for Osersk has been higher than in the rural results. The difference in background dose levels between two population results in different limits of accidental dose detection and individualization. The doses for 'Mayak' workers (Ozyorsk citizens) can be classed as anthropogenic if the EPR measurements exceed 120 mGy for teeth younger than 40 years, and 240 mGy for teeth older than 70 years. The anthropogenic doses for Techa River residents (rural population) would be higher than 95 mGy for teeth younger than 50 years and 270 mGy for

  14. EPR/alanine dosimetry for two therapeutic proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Marrale, Maurizio, E-mail: maurizio.marrale@unipa.it [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Gruppo V Sezione INFN di Catania, Via Santa Sofia, 64, 95123 Catania (Italy); Carlino, Antonio [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); EBG MedAustron GmbH, Marie Curie-Straße 5, A-2700 Wiener Neustadt (Austria); Gallo, Salvatore [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Gruppo V Sezione INFN di Catania, Via Santa Sofia, 64, 95123 Catania (Italy); Laboratorio PH3DRA, Dipartimento di Fisica e Astronomia, Università di Catania, Via Santa Sofia 64, 95123 Catania (Italy); Longo, Anna; Panzeca, Salvatore [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Gruppo V Sezione INFN di Catania, Via Santa Sofia, 64, 95123 Catania (Italy); Bolsi, Alessandra; Hrbacek, Jan; Lomax, Tony [Center for Proton Therapy, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland)

    2016-02-01

    In this work the analysis of the electron paramagnetic resonance (EPR) response of alanine pellets exposed to two different clinical proton beams employed for radiotherapy is performed. One beam is characterized by a passive delivery technique and is dedicated to the eyes treatment (OPTIS2 beam line). Alanine pellets were irradiated with a 70 MeV proton beam corresponding to 35 mm range in eye tissue. We investigated how collimators with different sizes and shape used to conform the dose to the planned target volume influence the delivered dose. For this purpose we performed measurements with varying the collimator size (Output Factor) and the results were compared with those obtained with other dosimetric techniques (such as Markus chamber and diode detector). This analysis showed that the dosimeter response is independent of collimator diameter if this is larger than or equal to 10 mm. The other beam is characterized by an active spot-scanning technique, the Gantry1 beam line (maximum energy 230 MeV), and is used to treat deep-seated tumors. The dose linearity of alanine response in the clinical dose range was tested and the alanine dose response at selected locations in depth was measured and compared with the TPS planned dose in a quasi-clinical scenario. The alanine response was found to be linear in the dose in the clinical explored range (from 10 to 70 Gy). Furthermore, a depth dose profile in a quasi-clinical scenario was measured and compared to the dose computed by the Treatment Planning System PSIPLAN. The comparison of calibrated proton alanine measurements and TPS dose shows a difference under 1% in the SOBP and a “quenching” effect up to 4% in the distal part of SOBP. The positive dosimetric characteristics of the alanine pellets confirm the feasibility to use these detectors for “in vivo” dosimetry in clinical proton beams.

  15. EPR dosimetry of teeth in past and future accidents: a prospective look at a retrospective method

    Energy Technology Data Exchange (ETDEWEB)

    Haskell, E.H.; Kenner, G.H.; Hayes, R.B. [Utah Univ., Salt Lake City, UT (United States). Center for Applied Dosimetry; Chumak, V.; Shalom, S. [All-Union Scientific Centre of Radiation Medicine, Kiev (Ukraine)

    1996-01-01

    Electron paramagnetic resonance spectroscopy (EPR) of tooth enamel is a relatively new technique for retrospective dosimetry that in the past two years has seen increasing effort towards its development and evaluation. Efforts have centered on determining the accuracy which may be achieved with current measurement techniques as well as the minimum doses detectable. The study was focused on evaluating some factors which influence the accuracy of EPR dosimetry of enamel. Reported are studies on sample intercomparisions, instrumental considerations, and effects of dental x-rays, environmental sunlight and ultraviolet radiation.

  16. Radiation chemistry of L-Alanine: application to EPR dosimetry (1)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M. J.; Jeo, Y. H.; Ha, Y. K.; Park, Y. S.; Choi, I. G. [KAERI, Taejon (Korea, Republic of)

    2003-10-01

    High energy ionizing radiation leaves stable radicals to certain organic materials, such as alanine and tartrate. Electron Paramagnetic Resonance (EPR) spectroscopy is a powerful tool for the identification and quantification of these radiation-induced radicals. An EPR method has been applied to study the radical characteristics of L-alanine after gamma radiation dose in the range of {approx}mGy to 60 kGy. The free radicals induced by gamma radiation were fairly stable, and EPR intensity, radical concentration, was proportional to the absorbed dose up to 60 kGy. From the results of our EPR measurements, it can be concluded that an alanine/EPR method is a useful technique for gamma radiation dosimetry from very low to high dose range.

  17. New developed cylindrical TM010 mode EPR cavity for X-band in vivo tooth dosimetry.

    Directory of Open Access Journals (Sweden)

    Guo Junwang

    Full Text Available EPR tooth in vivo dosimetry is an attractive approach for initial triage after unexpected nuclear events. An X-band cylindrical TM010 mode resonant cavity was developed for in vivo tooth dosimetry and used in EPR applications for the first time. The cavity had a trapezoidal measuring aperture at the exact position of the cavity's cylindrical wall where strong microwave magnetic field H1 concentrated and weak microwave electric field E1 distributed. Theoretical calculations and simulations were used to design and optimize the cavity parameters. The cavity features were evaluated by measuring DPPH sample, intact incisor samples embed in a gum model and the rhesus monkey teeth. The results showed that the cavity worked at designed frequency and had the ability to make EPR spectroscopy in relative high sensitivity. Sufficient modulation amplitude and microwave power could be applied into the aperture. Radiation induced EPR signal could be observed remarkably from 1 Gy irradiated intact incisor within only 30 seconds, which was among the best in scan time and detection limit. The in vivo spectroscopy was also realized by acquiring the radiation induced EPR signal from teeth of rhesus monkey whose teeth was irradiated by dose of 2 Gy. The results suggested that the cavity was sensitive to meet the demand to assess doses of significant level in short time. This cavity provided a very potential option for the development of X-band in vivo dosimetry.

  18. Retrospective dosimetry with EPR and OSL at McMaster University

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, J.W.; Boreham, D.R.; Rink, W.J.; Mistry, R. [McMaster Univ., Ontario (Canada)

    2010-07-01

    Retrospective dosimetry may be of use following a radiological incident, in order to determine whether individuals may have been exposed. We briefly review the fundamentals of two primary techniques for retrospective biophysical dosimetry: electron paramagnetic resonance (EPR) and optically-stimulated luminescence (OSL). Our facility at McMaster University has the capability to perform both EPR and OSL dosimetry, which provides us with the flexibility to study so-called 'fortuitous' dosimeters with the most appropriate technique. In this paper, we review our research of the past decade, during which we have developed techniques for the measurement of absorbed dose in human, rodent, and canine dental enamel, synthetic quartz oscillators, and gypsum wallboard. (author)

  19. High precision EPR dosimetry as a reference tool for validation of other techniques.

    Science.gov (United States)

    Chumak, V V; Sholom, S V; Bakhanova, E V; Pasalskaya, L F; Musijachenko, A V

    2005-02-01

    We present here a particular application area for EPR dosimetry with teeth--use as a source of reference dose values for validation/verification of other retrospective dosimetry techniques and existing dose records. The conditions of application of EPR dosimetry in this role as well as practical design of such studies are shown. Particular attention is given to the requirements to the techniques in terms of precision and throughput, as well as to the issue of availability of samples for analysis and practical solution of this problem. Practical application of this approach is illustrated by several examples of completed validation sub-studies, which were performed in the framework of large-scale post-Chernobyl epidemiological studies.

  20. Formates and dithionates: sensitive EPR-dosimeter materials for radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Lund, E. [Department of Medicine and Care, Radiation Physics, Faculty of Health Sciences, University of Linkoeping, S-581 85 Linkoeping (Sweden)]. E-mail: eva.lund@imv.liu.se; Gustafsson, H. [Department of Medicine and Care, Radiation Physics, Faculty of Health Sciences, University of Linkoeping, S-581 85 Linkoeping (Sweden); Danilczuk, M. [Chemical Physics Laboratory, IFM, University of Linkoeping, S-581 83 Linkoeping (Sweden); Sastry, M.D. [Chemical Physics Laboratory, IFM, University of Linkoeping, S-581 83 Linkoeping (Sweden); Lund, A. [Chemical Physics Laboratory, IFM, University of Linkoeping, S-581 83 Linkoeping (Sweden); Vestad, T.A. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Malinen, E. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Hole, E.O. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Sagstuen, E. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway)

    2005-02-01

    Polycrystalline formates and dithionates are promising materials for EPR dosimetry, as large yields of radiation induced stable radicals are formed with a linear dose response. Rapid spin relaxation rates were detected in many of the substances, indicating that a high microwave power can be applied during EPR acquisition in order to improve sensitivity. Different techniques used to further improve the sensitivity, such as the replacement of {sup 7}Li with {sup 6}Li or exchange of protons with deuterons in the corresponding crystalline matrices and metal ion doping are discussed. It is concluded that formates and dithionates may be up to 10 times as sensitive as L-{alpha}-alanine.

  1. EPR/Homotaurine: A possible dosimetry system for high doses

    Energy Technology Data Exchange (ETDEWEB)

    Maghraby, A., E-mail: maghrabism@yahoo.com [National Institute of Standards (NIS) - Radiation Dosimetry Department - Tersa st. 12211 Giza, P.O. Box 136 (Egypt); Salama, E. [Physics Department, Faculty of Science, Ain Shams University, 11566 Cairo (Egypt); Mansour, A. [National Center for Radiation Research and Technology, Atomic Energy Authority, Nasr City, Cairo (Egypt)

    2011-12-11

    An EPR investigation of radiation induced radicals in Homotaurine revealed that there are two types of radicals produced after exposure to gamma radiation ({sup 60}Co). EPR spectra were recorded and analyzed; also the microwave power saturation curves for both radicals were studied. The effect of change in modulation amplitude on peak-to-peak signal height and line width was investigated; this is in addition to the evaluation of energy dependence parameters compared to soft tissue and alanine dosimeters. Response of Homotaurine to different radiation doses (0.5 kGy-50 kGy) was studied and found to follow a linear relationship. Radiation induced radicals in Homotaurine persisted and showed a noticeable stability over 30 days following irradiation. It was found that Homotaurine possesses good dosimetric properties using EPR spectroscopy in high doses and is characterized by its simple spectrum.

  2. EPR/Homotaurine: A possible dosimetry system for high doses

    Science.gov (United States)

    Maghraby, A.; Salama, E.; Mansour, A.

    2011-12-01

    An EPR investigation of radiation induced radicals in Homotaurine revealed that there are two types of radicals produced after exposure to gamma radiation (60Co). EPR spectra were recorded and analyzed; also the microwave power saturation curves for both radicals were studied. The effect of change in modulation amplitude on peak-to-peak signal height and line width was investigated; this is in addition to the evaluation of energy dependence parameters compared to soft tissue and alanine dosimeters. Response of Homotaurine to different radiation doses (0.5 kGy-50 kGy) was studied and found to follow a linear relationship. Radiation induced radicals in Homotaurine persisted and showed a noticeable stability over 30 days following irradiation. It was found that Homotaurine possesses good dosimetric properties using EPR spectroscopy in high doses and is characterized by its simple spectrum.

  3. Review of the correlation between results of cytogenetic dosimetry from blood lymphocytes and EPR dosimetry from tooth enamel for victims of radiation accidents.

    Science.gov (United States)

    Khvostunov, I K; Ivannikov, A I; Skvortsov, V G; Nugis, V Yu; Golub, E V

    2015-03-01

    The goal of this study was to compare dose estimates from electron paramagnetic resonance (EPR) dosimetry with teeth and cytogenetic dosimetry with blood lymphocytes for 30 victims of radiation accidents. The whole-body exposures estimated by tooth enamel EPR dosimetry were ranging from 0.01 to 9.3 Gy. Study group comprised victims exposed to acute and prolonged irradiation at high and low dose rate in different accidents. Blood samples were taken from each of them for cytogenetic analysis. Aberrations were scored and analysed according to International Atomic Energy Agency (IAEA) guidelines for conventional and FISH analysis. Tooth samples were collected in dental clinics after they had been extracted during ordinary practice. EPR dosimetry was performed according to the IAEA protocol. EPR dosimetry showed good correlation with dosimetry based on chromosomal analysis. All estimations of cytogenetic dose below detection limit coincide with EPR dose estimates within the ranges of uncertainty. The differences between cytogenetic and EPR assays may occur in a case of previous unaccounted exposure, non-homogeneous irradiation and due to contribution to absorbed dose from neutron irradiation.

  4. Nonlinear Simulation of the Tooth Enamel Spectrum for EPR Dosimetry

    Science.gov (United States)

    Kirillov, V. A.; Dubovsky, S. V.

    2016-07-01

    Software was developed where initial EPR spectra of tooth enamel were deconvoluted based on nonlinear simulation, line shapes and signal amplitudes in the model initial spectrum were calculated, the regression coefficient was evaluated, and individual spectra were summed. Software validation demonstrated that doses calculated using it agreed excellently with the applied radiation doses and the doses reconstructed by the method of additive doses.

  5. The Chernobyl accident: EPR dosimetry on dental enamel of children

    Energy Technology Data Exchange (ETDEWEB)

    Gualtieri, G. E-mail: gianni@fismedw2.univaq.it; Colacicchi, S.; Sgattoni, R.; Giannoni, M

    2001-07-01

    The radiation dose on tooth enamel of children living close to Chernobyl has been evaluated by EPR. The sample preparation was reduced to a minimum of mechanical steps to remove a piece of enamel. A standard X-ray tube at low energy was used for additive irradiation. The filtration effect of facial soft tissue was taken into account. The radiation dose for a group of teeth slightly exceeds the annual dose, whereas for another group the dose very much exceeds the annual dose. Since the higher dose is found in teeth whose enamel have much lower EPR sensitivity to the radiation, it can be suggested that for these teeth the native signal could alter the evaluation of the smaller radiation signal.

  6. A sensitive EPR dosimetry system based on sulfamic acid

    Science.gov (United States)

    Maghraby, A.

    2007-08-01

    There is a need for a sensitive dosimeter using electron paramagnetic resonance spectroscopy (EPR) for use in medical applications, since with this method non-destructive read-out and dose archival could be achieved. Sulfamic acid as a possible detector substance was investigated before and after irradiation, its EPR spectra were recorded and analyzed, some dosimetric characteristics were studied: microwave power saturation behavior, the effect of modulation amplitude on peak-to-peak signal intensity and the line width. Energy-dependence parameters were compared to soft tissue and alanine, and the response to ionizing radiation was studied, also the decay behavior along 133 days after irradiation is presented. It is found that sulfamic acid possesses high-sensitivity and reasonable signal stability which may make it useful as a sensitive dosimeter for medical applications.

  7. The Chernobyl accident: EPR dosimetry on dental enamel of children.

    Science.gov (United States)

    Gualtieri, G; Colacicchi, S; Sgattoni, R; Giannoni, M

    2001-07-01

    The radiation dose on tooth enamel of children living close to Chernobyl has been evaluated by EPR. The sample preparation was reduced to a minimum of mechanical steps to remove a piece of enamel. A standard X-ray tube at low energy was used for additive irradiation. The filtration effect of facial soft tissue was taken into account. The radiation dose for a group of teeth slightly exceeds the annual dose, whereas for another group the dose very much exceeds the annual dose. Since the higher dose is found in teeth whose enamel have much lower EPR sensitivity to the radiation, it can be suggested that for these teeth the native signal could alter the evaluation of the smaller radiation signal.

  8. EPR dosimetry intercomparison using smart phone touch screen glass.

    Science.gov (United States)

    Fattibene, Paola; Trompier, Francois; Wieser, Albrecht; Brai, Maria; Ciesielski, Bartlomej; De Angelis, Cinzia; Della Monaca, Sara; Garcia, Tristan; Gustafsson, H; Hole, Eli Olag; Juniewicz, M; Krefft, K; Longo, Anna; Leveque, Philippe; Lund, Eva; Marrale, Maurizio; Michalec, Barbara; Mierzwińska, Gabriela; Rao, J L; Romanyukha, Alexander A; Tuner, Hasan

    2014-05-01

    This paper presents the results of an interlaboratory comparison of retrospective dosimetry using the electron paramagnetic resonance method. The test material used in this exercise was glass coming from the touch screens of smart phones that might be used as fortuitous dosimeters in a large-scale radiological incident. There were 13 participants to whom samples were dispatched, and 11 laboratories reported results. The participants received five calibration samples (0, 0.8, 2, 4, and 10 Gy) and four blindly irradiated samples (0, 0.9, 1.3, and 3.3 Gy). Participants were divided into two groups: for group A (formed by three participants), samples came from a homogeneous batch of glass and were stored in similar setting; for group B (formed by eight participants), samples came from different smart phones and stored in different settings of light and temperature. The calibration curves determined by the participants of group A had a small error and a critical level in the 0.37-0.40-Gy dose range, whereas the curves determined by the participants of group B were more scattered and led to a critical level in the 1.3-3.2-Gy dose range for six participants out of eight. Group A were able to assess the dose within 20 % for the lowest doses (smart phones need to be further investigated. An alongside conclusion is that the protocol was easily transferred to participants making a network of laboratories in case of a mass casualty event potentially feasible.

  9. Application of EPR retrospective dosimetry for large-scale accidental situation.

    Science.gov (United States)

    Skvortsov, V G; Ivannikov, A I; Stepanenko, V F; Tsyb, A F; Khamidova, L G; Kondrashov, A E; Tikunov, D D

    2000-05-01

    Above 3000 tooth enamel samples, collected at population of radioactive contaminated territories after Chernobyl accident, the Chernobyl liquidators, the retired military of high radiation risk and the population of control radiation free territories were investigated by EPR spectroscopy method in order to obtain accumulated individual exposure doses. Results of EPR spectra measurements are stored in data bank; enamel samples are also stored in order to provide the possibility to repeat the measurements in future. Statistical analysis of results has allowed to detect the contribution into EPR signal in tooth enamel due to the action of the natural background radiation, and the radioactive contamination of territory. In general, the average doses of external exposure of the population obtained with EPR spectroscopy of teeth enamel are consistent with results based on other methods of direct and retrospective dosimetry. Essential exceeding of the individual doses above the average level within the population groups was observed for some persons. That gave the possibility to detect the individuals with overexposure, which were included into groups for medical monitoring.

  10. Internal in vitro dosimetry for fish using hydroxyapatite-based EPR detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, D.V. [Urals Division of Russian Academy of Sciences, Institute of Metal Physics, Yekaterinburg (Russian Federation); Ural Federal University, Yekaterinburg (Russian Federation); Shishkina, E.A.; Osipov, D.I.; Pryakhin, E.A. [Urals Research Center for Radiation Medicine, Chelyabinsk (Russian Federation); Razumeev, R.A. [Ural Federal University, Yekaterinburg (Russian Federation)

    2015-08-15

    A number of aquatic ecosystems were exposed to ionizing radiation as a result of the activities of the Mayak Production Association in the Southern Urals, former Soviet Union, in the 1950s. Currently, fishes inhabiting contaminated lakes are being actively studied. These investigations need dosimetric support. In the present paper the results of a pilot study for elaborating an EPR dosimeter which can be used for internal dosimetry in vitro are described. Biological hydroxyapatite is proposed here to be used as a detecting substance. More specifically, small hydroxyapatite grains are proposed for use as point detectors fixed in a solid matrix. After having been pelletized, the detectors were covered by Mylar and placed in the body of a fish to be stored in the fridge for several months. Application of the detectors for internal fish dosimetry demonstrated that the enamel sensitivity is sufficient for passive detection of ionizing radiation in fishes inhabiting contaminated lakes in the Southern Urals. (orig.)

  11. Study for applying microwave power saturation technique on fingernail/EPR dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byeong Ryong; Choi, Hoon; Nam, Hyun Ill; Lee, Byung Ill [Radiation Health Research Institute, Seoul (Korea, Republic of)

    2012-10-15

    There is growing recognition worldwide of the need to develop effective uses of dosimetry methods to assess unexpected exposure to radiation in the event of a large scale event. One of physically based dosimetry methods electron paramagnetic resonance (EPR) spectroscopy has been applied to perform retrospective radiation dosimetry using extracted samples of tooth enamel and nail(fingernail and toenail), following radiation accidents and exposures resulting from weapon use, testing, and production. Human fingernails are composed largely of a keratin, which consists of {alpha} helical peptide chains that are twisted into a left handed coil and strengthened by disulphide cross links. Ionizing radiation generates free radicals in the keratin matrix, and these radicals are stable over a relatively long period (days to weeks). Most importantly, the number of radicals is proportional to the magnitude of the dose over a wide dose range (0{approx}30 Gy). Also, dose can be estimated at four different locations on the human body, providing information on the homogeneity of the radiation exposure. And The results from EPR nail dosimetry are immediately available However, relatively large background signal (BKS) converted from mechanically induced signal (MIS) after cutting process of fingernail, normally overlaps with the radiation induced signal (RIS), make it difficult to estimate accurate dose accidental exposure. Therefore, estimation method using dose response curve was difficult to ensure reliability below 5 Gy. In this study, In order to overcome these disadvantages, we measured the reactions of RIS and BKS (MIS) according to the change of Microwave power level, and researched about the applicability of the Power saturation technique at low dose.

  12. The 4th international comparison on EPR dosimetry with tooth enamel

    Energy Technology Data Exchange (ETDEWEB)

    Fattibene, P., E-mail: paola.fattibene@iss.it [Istituto Superiore di Sanita, Department of Technology and Health, Viale Regina Elena 299, I-00162 Rome (Italy); Wieser, A. [Helmholtz Zentrum Muenchen, Neuherberg D-85764 (Germany); Adolfsson, E. [Linkoeping University, SE-58185 Linkoeping (Sweden); Benevides, L.A. [Naval Dosimetry Center, Bethesda MD 20889-5600 (United States); Brai, M. [University of Palermo, I-90128 Palermo (Italy); Callens, F. [Ghent University, B-9000 Gent (Belgium); Chumak, V. [Research Center for Radiation Medicine AMS, 04050 Kiev (Ukraine); Ciesielski, B. [Medical University of Gdansk, 80-211 Gdansk (Poland); Della Monaca, S. [Istituto Superiore di Sanita, Department of Technology and Health, Viale Regina Elena 299, I-00162 Rome (Italy); Regina Elena Institute, I-00144 Rome (Italy); Emerich, K. [Medical University of Gdansk, 80-211 Gdansk (Poland); Department of Paediatric Dentistry, 80-208 Gdansk (Poland); Gustafsson, H. [Linkoeping University, SE-58185 Linkoeping (Sweden); Hirai, Y. [Radiation Effects Research Foundation, Minami-ku, Hiroshima 732-0815 (Japan); Hoshi, M. [Hiroshima University, Minami-ku, Hiroshima 734-8553 (Japan); Israelsson, A. [Linkoeping University, SE-58185 Linkoeping (Sweden); Ivannikov, A. [Medical Radiological Research Center, Obninsk, Kaluga region (Russian Federation); Ivanov, D. [Institute of Metal Physics, Yekaterinburg 620041 (Russian Federation); Kaminska, J. [Medical University of Gdansk, 80-211 Gdansk (Poland); Ke, Wu [Beijing Institute of Radiation Medicine, Beijing 100850 (China); Lund, E. [Linkoeping University, SE-58185 Linkoeping (Sweden); Marrale, M. [University of Palermo, I-90128 Palermo (Italy)

    2011-09-15

    This paper presents the results of the 4th International Comparison of in vitro electron paramagnetic resonance dosimetry with tooth enamel, where the performance parameters of tooth enamel dosimetry methods were compared among sixteen laboratories from all over the world. The participating laboratories were asked to determine a calibration curve with a set of tooth enamel powder samples provided by the organizers. Nine molar teeth extracted following medical indication from German donors and collected between 1997 and 2007 were prepared and irradiated at the Helmholtz Zentrum Muenchen. Five out of six samples were irradiated at 0.1, 0.2, 0.5, 1.0 and 1.5 Gy air kerma; and one unirradiated sample was kept as control. The doses delivered to the individual samples were unknown to the participants, who were asked to measure each sample nine times, and to report the EPR signal response, the mass of aliquots measured, and the parameters of EPR signal acquisition and signal evaluation. Critical dose and detection limit were calculated by the organizers on the basis of the calibration-curve parameters obtained at every laboratory. For calibration curves obtained by measuring every calibration sample three times, the mean value of the detection limit was 205 mGy, ranging from 56 to 649 mGy. The participants were also invited to provide the signal response and the nominal dose of their current dose calibration curve (wherever available), the critical dose and detection limit of which were also calculated by the organizers.

  13. Use of aspartame-based sweetener tablets in emergency dosimetry using EPR.

    Science.gov (United States)

    Maghraby, A; Salama, E

    2010-06-01

    Accident dosimetry aims to evaluate the unplanned radiation doses delivered to individuals through one of the objects exist in the area of the accident. The gamma dose response of free radicals generated in irradiated aspartame tablets and its usability for emergency dosimetry was studied. EPR spectra of unirradiated and irradiated aspartame-based sweetener were recorded. Two signals arise after irradiating, S(1) at g (S(1)) = 2.00229 +/- 0.00097 and S(2) at g (S(2)) = 2.00262 +/- 0.00088. Some EPR parameters were studied for radiation-induced radicals in aspartame sweeteners tablets, such as the microwave saturation behaviour, the effect of magnetic field modulation amplitude on the peak-to-peak height and peak-to-peak line width for both of S(1) and S(2). Responses of S(1) and S(2) to different radiation doses were studied and resulted in linear relationships, radicals persistence curves were plotted over a 49-d storage period. It was found that Aspartame sweeteners tablets are useful in the range from 0.96 to 39.96 Gy. Radiation-induced radicals possess reasonable stability.

  14. EPR dosimetry teeth in past and future accidents: A prospective look at a retrospective method

    Energy Technology Data Exchange (ETDEWEB)

    Haskell, E.; Kenner, G.; Hayes, R. [Univ. of Utah, Salt Lake City, UT (United States). Center for Applied Dosimetry; Chumak, V.; Shalom, S. [Scientific Center for Radiation Medicine, Kiev (Ukraine)

    1997-03-01

    Accurate assessments of doses received by individuals exposed to radiation from nuclear accidents and incidents such as those at Hiroshima and Nagasaki, the Nevada test site, Cheliabinsk and Mayak are required for epidemiological studies seeking to establish relationships between radiation dose and health effects. One method of retrospective dosimetry which allows for measurement of cumulative gamma ray doses received by exposed individuals is electron paramagnetic resonance spectroscopy (EPR) of tooth enamel. Tooth enamel stores and retains, indefinitely, information on absorbed radiation dose. And teeth are available in every population as a result of dental extraction for medical reasons including periodontal disease and impacted wisdom teeth. In the case of children, deciduous teeth, which are shed between the ages of 7 and 13, can be a very important dosimetric source if documented collection is implemented shortly following an accident.

  15. EPR dosimetry of teeth in past and future accidents. A prospective look at a retrospective method

    Energy Technology Data Exchange (ETDEWEB)

    Haskell, E.; Kenner, G.; Hayes, R. [Center for Applied Dosimetry, Salt Lake City, UT (United States); Chumak, V.; Shalom, S.

    1996-12-31

    Accurate assessments of doses received by individuals exposed to radiation from nuclear accidents and incidents such as those at Hiroshima and Nagasaki, the Nevada test site, Chelyabinsk and Mayak are required for epidemiological studies seeking to establish relationships between radiation dose and health effects. One method of retrospective dosimetry which allows for measurement of cumulative gamma ray doses received by exposed individuals is electron paramagnetic resonance spectroscopy (EPR) of tooth enamel. Tooth enamel stores and retains, indefinitely, information on absorbed radiation dose; and teeth are available in every population as a result of dental extraction for medical reasons including periodontal disease and impacted wisdom teeth. In the case of children, deciduous teeth, which are shed between the ages of 7 and 13, can be a very important dosimetric source if documented collection is implemented shortly following an accident. (author)

  16. Compounds of 6Li and natural Li for EPR dosimetry in photon/neutron mixed radiation fields.

    Science.gov (United States)

    Lund, E; Gustafsson, H; Danilczuk, M; Sastry, M D; Lund, A

    2004-05-01

    Formates and dithionates of 6Li, enriched and 7Li in natural composition of Li offer a possibility to measure the absorbed dose from photons and thermal neutrons in a mixed radiation field for instance at a boron neutron capture therapy (BNCT) facility. Tests with formates and dithionates of enriched 6Li and lithium compounds with natural composition have been performed at the BNCT facility at Studsvik, Sweden. Irradiations have been performed at 3 cm depth in a Perspex phantom in a fluence rate of thermal neutrons 1.8 x 10(9) n cm(-2) s(-1). The compounds were also irradiated in a pure X-ray field from a 4MV linear accelerator at 5 cm depth in a phantom with accurately determined absorbed doses. The signal intensity and shape was investigated within 3 h after the irradiation. A single line spectrum attributed to the CO2- radical was observed after irradiation of lithium formate. An increase in line width occurring after neutron irradiation in comparison with photon irradiation of the 6Li sample was attributed to dipolar broadening between CO2- radicals trapped in the tracks of the alpha particles. A spectrum due to the SO3- radical anion was observed after irradiation of lithium dithionate. The signal amplitude increased using the 6Li in place of the Li with natural composition of isotopes, in studies with low energy X-ray irradiation. Due to the decreased line width, caused by the difference in g(N) and I between the isotopes, the sensitivity with 6Li dithionate may be enhanced by an order of magnitude compared to alanine dosimetry. After comprehensive examination of the different combinations of compounds with different amounts of 6Li and 7Li regarding dosimetry, radiation chemistry and EPR properties these dosimeter material might be used for dose determinations at BNCT treatments and for biomedical experiments. Interesting properties of the radical formation might be visible due to the large difference in ionization density of neutrons compared to photons.

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

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Felipe [Departmento de Fisica e Matematica, FFCLRP-Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto-SP (Brazil); Department of Radiological Health, Caja de Seguro Social, Panama City (Panama); Department of Physics, Faculty of Natural and Exact Sciences and Technology, University of Panama, Panama City (Panama); Graeff, Carlos F.O. [Departmento de Fisica e Matematica, FFCLRP-Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto-SP (Brazil); Baffa, Oswaldo [Departmento de Fisica e Matematica, FFCLRP-Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto-SP (Brazil)

    2005-02-01

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

  18. Preliminary evaluation of second harmonic direct detection scheme for low-dose range in alanine/EPR dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Felipe [Departamento de Fisica e Matematica, FFCLRP, Universidade de Sao Paulo, Ribeirao Preto, SP (Brazil); Departamento de Fisica, Facultad de Ciencias Naturales, Exactas y Tecnologia, Universidad de Panama (Panama); Departamento de Salud Radiologica, Caja de Seguro Social (Panama); Graeff, Carlos F.O.; Baffa, Oswaldo [Departamento de Fisica e Matematica, FFCLRP, Universidade de Sao Paulo, Ribeirao Preto, SP (Brazil)]. E-mail: baffa@ffclrp.usp.br

    2002-04-21

    The usefulness of a direct detection scheme of the second harmonic (2h) overmodulated signal from irradiated alanine in EPR dosimetry was studied. For this purpose, a group of DL-alanine/paraffin cylindrical pellets was produced. The dosimeters were irradiated with a {sup 60}Co radiotherapy gamma source with doses of 0.05, 0.1, 0.5, 1 and 5 Gy. The EPR measurements were carried out in a VARIAN-E4 spectrometer operating in X-band with optimized parameters to obtain highest amplitude signals of both harmonics. The 2h signal was detected directly at twice the modulation frequency. In preliminary results, the 2h showed some advantages over the 1h such as better resolution for doses below 1 Gy, better repeatability results and better linear behaviour in the dose range indicated. (author)

  19. Testing and linearity calibration of films of phenol compounds exposed to thermal neutron field for EPR dosimetry.

    Science.gov (United States)

    Gallo, S; Panzeca, S; Longo, A; Altieri, S; Bentivoglio, A; Dondi, D; Marconi, R P; Protti, N; Zeffiro, A; Marrale, M

    2015-12-01

    This paper reports the preliminary results obtained by Electron Paramagnetic Resonance (EPR) measurements on films of IRGANOX® 1076 phenols with and without low content (5% by weight) of gadolinium oxide (Gd2O3) exposed in the thermal column of the Triga Mark II reactor of LENA (Laboratorio Energia Nucleare Applicata) of Pavia (Italy). Thanks to their size, the phenolic films here presented are good devices for the dosimetry of beams with high dose gradient and which require accurate knowledge of the precise dose delivered. The dependence of EPR signal as function of neutron dose was investigated in the fluence range between 10(11) cm(-2) and 10(14) cm(-2). Linearity of EPR response was found and the signal was compared with that of commercial alanine films. Our analysis showed that gadolinium oxide (5% by weight) can enhance the thermal neutron sensitivity more than 18 times. Irradiated dosimetric films of phenolic compound exhibited EPR signal fading of about 4% after 10 days from irradiation.

  20. Assessment of an alanine EPR dosimetry technique with enhanced precision and accuracy

    CERN Document Server

    Hayes, R B; Wieser, A; Romanyukha, A A; Hardy, B L; Barrus, J K

    2000-01-01

    Dose reconstruction in the course of a series of blind tests demonstrated that an accuracy of 10 mGy for low doses and 1% for high doses can be achieved using EPR spectroscopy. This was accomplished using a combination of methodologies including polynomial filtration of the EPR spectrum, dosimeter rotation during scanning, use of an EPR standard fixed into the resonator and subtraction of all nonradiogenic signals. Doses were reconstructed over the range of 0.01-1000 Gy using this compound spectral EPR analysis. This EPR technique, being equally applicable to fractionated doses (such as those delivered during multiple radiotherapy treatments), was verified to exhibit dose reciprocity. Irradiated alanine dosimeters which were stored exhibited compound spectral EPR signal fading of ca 3% over 9 months. All error estimates given in this paper are given at the 1 standard deviation level and unless otherwise specified do not account for uncertainties in source calibration.

  1. EPR dosimetry in tooth enamel by x radiation; Dosimetria EPR en esmalte dental irradiado con rayos X

    Energy Technology Data Exchange (ETDEWEB)

    Dubner, Diana; Perez, Maria del Rosario; Gisone, P. [Autoridad Regulatoria Nuclear, Buenos Aires (Argentina)] E-mail: ddubner@cae.arn.gov.ar; Fainstein, C.; Winkler, E. [Comision Nacional de Energia Atomica (CNEA), San Carlos de Bariloche (Argentina). Centro Atomico Bariloche]|[Universidad Nacional de Cuyo, Mendoza (Argentina). Inst. Balseiro; Saravi, Margarita [Comision Nacional de Energia Atomica (CNEA) (Argentina). Centro Atomico Ezeiza; Davila, Francisco [Ateneo Argentino de Odontologia, Buenos Aires (Argentina)

    2001-07-01

    Tooth enamel, extracted from molars, was irradiated with 66 keV X-rays, with doses up to 1 Gy. The preparation of the powder samples is described, as well as the protocol for the acquisition and processing of the spectra. The radiation induced paramagnetism is measured, at room temperature, by ESR spectroscopy. The ESR spectra is well described considering two paramagnetic species, with magnetic moments (in units of Bohr magnetrons) g=2,0041, and g1=2,0018, g2=1,9972. The ESR data (peak-to-peak amplitude per mg, hpp/mg, vs dose D), for doses 0 Gydosimetry. (author)

  2. Influence of free radicals signal from dental resins on the radio-induced signal in teeth in EPR retrospective dosimetry.

    Science.gov (United States)

    Levêque, Philippe; Desmet, Céline; Dos Santos-Goncalvez, Ana Maria; Beun, Sébastien; Leprince, Julian G; Leloup, Gaëtane; Gallez, Bernard

    2013-01-01

    In case of radiological accident, retrospective dosimetry is needed to reconstruct the absorbed dose of overexposed individuals not wearing personal dosimeters at the onset of the incident. In such a situation, emergency mass triage will be required. In this context, it has been shown that Electron Paramagnetic Resonance (EPR) spectroscopy would be a rapid and sensitive method, on the field deployable system, allowing dose evaluation of a great number of people in a short time period. This methodology uses tooth enamel as a natural dosimeter. Ionising radiations create stable free radicals in the enamel, in a dose dependent manner, which can be detected by EPR directly in the mouth with an appropriate resonator. Teeth are often subject to restorations, currently made of synthetic dimethacrylate-based photopolymerizable composites. It is known that some dental composites give an EPR signal which is likely to interfere with the dosimetric signal from the enamel. So far, no information was available about the occurrence of this signal in the various composites available on the market, the magnitude of the signal compared to the dosimetric signal, nor its evolution with time. In this study, we conducted a systematic characterization of the signal (intensity, kinetics, interference with dosimetric signal) on 19 most widely used composites for tooth restoration, and on 14 experimental resins made with the most characteristic monomers found in commercial composites. Although a strong EPR signal was observed in every material, a rapid decay of the signal was noted. Six months after the polymerization, the signal was negligible in most composites compared to a 3 Gy dosimetric signal in a tooth. In some cases, a stable atypical signal was observed, which was still interfering with the dosimetric signal.

  3. Influence of free radicals signal from dental resins on the radio-induced signal in teeth in EPR retrospective dosimetry.

    Directory of Open Access Journals (Sweden)

    Philippe Levêque

    Full Text Available In case of radiological accident, retrospective dosimetry is needed to reconstruct the absorbed dose of overexposed individuals not wearing personal dosimeters at the onset of the incident. In such a situation, emergency mass triage will be required. In this context, it has been shown that Electron Paramagnetic Resonance (EPR spectroscopy would be a rapid and sensitive method, on the field deployable system, allowing dose evaluation of a great number of people in a short time period. This methodology uses tooth enamel as a natural dosimeter. Ionising radiations create stable free radicals in the enamel, in a dose dependent manner, which can be detected by EPR directly in the mouth with an appropriate resonator. Teeth are often subject to restorations, currently made of synthetic dimethacrylate-based photopolymerizable composites. It is known that some dental composites give an EPR signal which is likely to interfere with the dosimetric signal from the enamel. So far, no information was available about the occurrence of this signal in the various composites available on the market, the magnitude of the signal compared to the dosimetric signal, nor its evolution with time. In this study, we conducted a systematic characterization of the signal (intensity, kinetics, interference with dosimetric signal on 19 most widely used composites for tooth restoration, and on 14 experimental resins made with the most characteristic monomers found in commercial composites. Although a strong EPR signal was observed in every material, a rapid decay of the signal was noted. Six months after the polymerization, the signal was negligible in most composites compared to a 3 Gy dosimetric signal in a tooth. In some cases, a stable atypical signal was observed, which was still interfering with the dosimetric signal.

  4. Taurine-EVA copolymer-paraffin rods dosimeters for EPR high-dose radiation dosimetry

    OpenAIRE

    Maghraby Ahmed M.; Mansour A; Abdel-Fattah A. A.

    2014-01-01

    Taurine/EPR rods (3 × 10 mm) have been prepared by a simple technique in the laboratory where taurine powder was mixed with a molten mixture of paraffin wax and an ethylene vinyl acetate (EVA) copolymer. The binding mixture EVA/Paraffin does not present interference or noise in the EPR signal before or after irradiation. The rods show good mechanical properties for safe and multi-use handling. An EPR investigation of radiation induced radicals in taurine rods revealed that there are two types...

  5. Taurine-EVA copolymer-paraffin rods dosimeters for EPR high-dose radiation dosimetry

    Directory of Open Access Journals (Sweden)

    Maghraby Ahmed M.

    2014-03-01

    Full Text Available Taurine/EPR rods (3 × 10 mm have been prepared by a simple technique in the laboratory where taurine powder was mixed with a molten mixture of paraffin wax and an ethylene vinyl acetate (EVA copolymer. The binding mixture EVA/Paraffin does not present interference or noise in the EPR signal before or after irradiation. The rods show good mechanical properties for safe and multi-use handling. An EPR investigation of radiation induced radicals in taurine rods revealed that there are two types of radicals produced after exposure to gamma radiation (60Co. EPR spectra were recorded and analyzed - also the microwave power saturation and modulation amplitude were studied and optimized. Response of taurine to different radiation doses (1.5-100 kGy was studied and found to follow a linear relationship up to 100 kGy. Radiation induced radicals in taurine persists and showed a noticeable stability over 94 days following irradiation. Uncertainities associated with the evaluation of radiation doses using taurine dosimeters were discussed and tabulated. It was found that taurine possesses good dosimetric properties using EPR spectroscopy in high doses in addition to its simple spectrum.

  6. Response of L-alanine and 2-methylalanine minidosimeters for K-Band (24 GHz) EPR dosimetry

    Science.gov (United States)

    Chen, F.; Graeff, C. F. O.; Baffa, O.

    2007-11-01

    Minidosimeters of L-alanine and 2-methylalanine (2MA) were prepared and tested as potential candidates for small radiation field dosimetry. To quantify the free radicals created by radiation a K-Band (24 GHz) EPR spectrometer was used. X-rays provided by a 6 MV clinical linear accelerator were used to irradiate the minidosimeters in the dose range of 0.5-30 Gy. The dose-response curves for both radiation sensitive materials displayed a good linear behavior in the dose range indicated with 2MA being more radiation sensitive than L-alanine. Moreover, 2MA showed a smaller LLD (lower limit detection) value. The proposed system minidosimeter/K-Band spectrometer was able to detect 10 Gy EPR spectra with good signal-to-noise ratio (S/N). The overall uncertainty indicates that this system shows a good performance for the detection of dose values of 20 Gy and above, which are dose values typically used in radiosurgery treatments.

  7. Tissue interfaces dosimetry in small field radiotherapy with alanine/EPR mini dosimeters and Monte Carlo-Penelope simulation

    Energy Technology Data Exchange (ETDEWEB)

    Vega R, J. L.; Nicolucci, P.; Baffa, O. [Universidade de Sao Paulo, FFCLRP, Departamento de Fisica, Av. Bandeirantes 3900, Bairro Monte Alegre, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Chen, F. [Universidade Federale do ABC, CCNH, Rua Santa Adelia 166, Bangu, 09210-170 Santo Andre, Sao Paulo (Brazil); Apaza V, D. G., E-mail: josevegaramirez@yahoo.es [Universidad Nacional de San Agustin de Arequipa, Departamento de Fisica, Arequipa (Peru)

    2014-08-15

    The dosimetry system based on alanine mini dosimeters plus K-Band EPR spectrometer was tested in the tissue-interface dosimetry through the percentage depth-dose (Pdd) determination for 3 x 3 cm{sup 2} and 1 x 1 cm{sup 2} radiation fields sizes. The alanine mini dosimeters were produced by mechanical pressure from a mixture of 95% L-alanine and 5% polyvinyl alcohol (Pva) acting as binder. Nominal dimensions of these mini dosimeters were 1 mm diameter and 3 mm length as well as 3 - 4 mg mass. The EPR spectra of the mini dosimeters were registered using a K-Band (24 GHz) EPR spectrometer. The mini dosimeters were placed in a nonhomogeneous phantom and irradiated with 20 Gy in a 6 MV PRIMUS Siemens linear accelerator, with a source-to-surface distance of 100 cm using the small fields previously mentioned. The cylindrical non-homogeneous phantom was comprised of several disk-shaped plates of different materials in the sequence acrylic-bone cork-bone-acrylic, with dimensions 15 cm diameter and 1 cm thick. The plates were placed in descending order, starting from top with four acrylic plates followed by two bone plates plus eight cork plates plus two bone plates and finally, four acrylic plates (4-2-8-2-4). Pdd curves from the treatment planning system and from Monte Carlo simulation with Penelope code were determined. Mini dosimeters Pdd results show good agreement with Penelope, better than 95% for the cork homogeneous region and 97.7% in the bone heterogeneous region. In the first interface region, between acrylic and bone, it can see a dose increment of 0.6% for mini dosimeters compared to Penelope. At the second interface, between bone and cork, there is 9.1% of dose increment for mini dosimeter relative to Penelope. For the third (cork-bone) and fourth (bone-acrylic) interfaces, the dose increment for mini dosimeters compared to Penelope was 4.1% both. (Author)

  8. Analysis of various modifications in spectra analysis on accuracy of dose reconstructions in EPR dosimetry in tooth enamel

    Energy Technology Data Exchange (ETDEWEB)

    Ciesielski, B., E-mail: bciesiel@gumed.edu.pl [Department of Physics and Biophysics, Medical University of Gdansk, Debinki 1, 80-211 Gdansk (Poland); Kaminska, J. [Department of Oncology and Radiotherapy, Medical University of Gdansk, Debinki 7, 80-211 Gdansk (Poland); Emerich, K. [Department of Paediatric Dentistry, Medical University of Gdansk, Orzeszkowej 18, 80-208 Gdansk (Poland)

    2011-09-15

    The results of EPR measurements performed due to our participation in the 4th International Comparison of EPR Dosimetry using tooth enamel were used to analyze the effects of modifications in numerical analysis of the measured spectra on precision and accuracy of reconstructed doses. The studied modifications included effects of: (1) a use of Mn{sup 2+} standard, (2) variations in experimental native background signals of tooth enamel used for dose reconstructions, (3) signal filtration, (4) subtraction of empty tube spectra, and (5) variations in the spectra ranges used for calculations (fitting windows). It was shown, that the use of a Mn standard, for normalization of intensities of the recorded signals in the spectra processing, strongly increased the dosimetric accuracy. The regression lines of the doses reconstructed using different background spectra against nominal doses, obtained without Mn standard, had slopes about 30% higher and their scatter range was about 2 times higher than the same parameters obtained when Mn standard was applied in the spectra processing. Accuracy of the measured doses characterized by root mean square deviations from the nominal doses was 71 mGy for calculations with Mn standard and 241 mGy without normalization to Mn lines. Despite the large beneficial effect of the use of Mn standard on accuracy (root mean square deviations of the data, slope of the regression lines), it did not significantly improve the dosimetry performance characterized by the critical dose and detection limit. The smoothing of the spectra by 9 point filtration resulted in 1.6% increase of the reconstructed doses. The subtraction of empty tube spectrum had no effect on precision and accuracy of the dose reconstruction. The performance parameters were also practically insensitive to a choice of a width of the spectral window used for the analysis, provided it encompassed the {approx}1.6 mT range covering the main peaks of the radiation induced signal in

  9. Irradiated bivalve mollusks: Use of EPR spectroscopy for identification and dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Alberti, Angelo, E-mail: aalberti@isof.cnr.it [CNR-ISOF, Area della Ricerca di Bologna, Via P. Gobetti 101, Bologna I-40129 (Italy); Chiaravalle, Eugenio [Istituto Zooprofilattico Sperimentale della Puglia e Basilicata, Via Manfredonia 20, Foggia I-71100 (Italy); Fuochi, Piergiorgio; Macciantelli, Dante [CNR-ISOF, Area della Ricerca di Bologna, Via P. Gobetti 101, Bologna I-40129 (Italy); Mangiacotti, Michele, E-mail: michelemangiacotti@libero.it [Istituto Zooprofilattico Sperimentale della Puglia e Basilicata, Via Manfredonia 20, Foggia I-71100 (Italy); Marchesani, Giuliana [Istituto Zooprofilattico Sperimentale della Puglia e Basilicata, Via Manfredonia 20, Foggia I-71100 (Italy); Plescia, Elena [CNR-ISOF, Area della Ricerca di Bologna, Via P. Gobetti 101, Bologna I-40129 (Italy)

    2011-12-15

    High energy radiation treatment of foodstuff for microbial control and shelf-life extension is being used in many countries. However, for consumer protection and information, the European Union has adopted the Directives 1999/2/EC and 1999/3/EC to harmonize the rules concerning the treatment and trade of irradiated foods in EU countries. Among the validated methods to detect irradiated foods the EU directives also include Electron Paramagnetic Resonance (EPR/ESR) spectroscopy. We describe herein the use of EPR for identification of four species of bivalve mollusks, i.e. brown Venus shells (Callista chione), clams (Tapes semidecussatus), mussels (Mytilus galloprovincialis) and oysters (Ostrea edulis) irradiated with {sup 60}Co {gamma}-rays. EPR could definitely identify irradiated seashells due to the presence of long-lived free radicals, primarily CO{sub 2}{sup -}, CO{sub 3}{sup 3-}, SO{sub 2}{sup -} and SO{sub 3}{sup -} radical anions. The presence of other organic free radicals, believed to originate from conchiolin, a scleroprotein present in the shells, was also ascertained. The use of one of these radicals as a marker for irradiation of brown Venus shells and clams can be envisaged. We also propose a dosimetric protocol for the reconstruction of the administered dose in irradiated oysters. - Highlights: > EPR spectroscopy is confirmed a valuable identification tool for irradiated mollusks. > A conchiolin-derived radical can be used as irradiation marker for some mollusks. > A reliable protocol is outlined for dose reconstruction of irradiated oysters.

  10. EPR response characterization of drugs excipients for applying in accident dosimetry; Caracterizacao da resposta RPE dos excipientes dos medicamentos para aplicacao em dosimetria de acidente

    Energy Technology Data Exchange (ETDEWEB)

    Marczewski, Barbara S.; Rodrigues Junior, Orlando; Galante, Ocimar L.; Costa, Zelia M. da; Campos, Leticia L. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    2002-07-01

    Some drugs are widely used by the population and can be employed to dose retrospective. The carbohydrates (saccharides), commonly used as excipients in the pharmaceutical industry, produce a quantity of free radicals after gamma irradiation, making them useful for dosimetry in emergency or accident situations that imply in dose evaluation from the materials found nearly or in contact with victims. In general, EPR signal from pulverized pills of some drugs are very complex due to the variety of components in the formulation. Because of this fact, some pharmaceutical excipients identified in the pill composition were also analysed by EPR spectrometry. On the counter drugs were studied: Cebion glucose, AAS, Aspirina, Conmel, Lacto-Purga and sugar substitutive ZeroCal. The excipients were: lactose, amide, anhydrous glucose and magnesium stearate. In some samples the number of radicals produced increased with the dose, showing a linear response for a dose range of interest and an adequate sensibility for dosimetry in accident cases.

  11. Spectra processing at tooth enamel dosimetry: Analytical description of EPR spectrum at different microwave power

    Energy Technology Data Exchange (ETDEWEB)

    Tieliewuhan, E. [Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553 (Japan); Ivannikov, A. [Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553 (Japan) and Medical Radiological Research Center of RAMS, Korolyov str., 4, Obninsk 249036 (Russian Federation)]. E-mail: ivann@mail.ru; Zhumadilov, K. [Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553 (Japan); Nalapko, M. [Medical Radiological Research Center of RAMS, Korolyov str., 4, Obninsk 249036 (Russian Federation); Tikunov, D. [Medical Radiological Research Center of RAMS, Korolyov str., 4, Obninsk 249036 (Russian Federation); Skvortsov, V. [Medical Radiological Research Center of RAMS, Korolyov str., 4, Obninsk 249036 (Russian Federation); Stepanenko, V. [Medical Radiological Research Center of RAMS, Korolyov str., 4, Obninsk 249036 (Russian Federation); Toyoda, S. [Department of Applied Physics, Okayama University of Science, 1-1 Ridai, Okayama 700-0005 (Japan); Tanaka, K. [Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553 (Japan); Endo, S. [Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553 (Japan); Hoshi, M. [Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553 (Japan)

    2006-04-15

    Variation of the electron paramagnetic resonance (EPR) spectrum of the human tooth enamel recorded at different microwave power is investigated. The analytical models describing the native and the radiation-induced signals in the enamel are proposed, which fit the experimental spectra in wide range of microwave power. These models are designed to use for processing the spectra of irradiated enamel at determination of the absorbed dose from the intensity of the radiation-induced signal.

  12. Radiation-induced defects in strontium carbonate rod for EPR dosimetry applications

    Science.gov (United States)

    Rushdi, M. A. H.; Abdel-Fattah, A. A.; Soliman, Y. S.

    2017-02-01

    The radiation-induced defects in strontium carbonate (SrCO3) rod dosimeter in the dose range of 2.5 Gy-25 kGy was investigated using electron paramagnetic resonance (EPR) technique. The EPR spectra of γ-irradiated strontium carbonate (SC) rods exhibit a strong EPR signal with the spectroscopic splitting g-factor 2.008 and a weak signal at g-factor 2.003. This signal increases with increasing irradiation dose. The dose-response function has a good linearity in the low dose range of 2.5-500 Gy and slight sub-linearity in the high dose range of 0.5-25 kGy. The dosimeter is nearly humidity independent in the level of 33-77% relative humidity during irradiation. The temperature coefficient of the dose-response function is 0.22% per °C in the temperature range of 20-40 °C. The rod dosimeter exhibits a maximum deviation from water equivalency by 7% in the energy range of 0.3-5 MeV. The overall uncertainty of dose determination using SC dosimeter is 5.2% and 4.54% (2σ) for low and high dose range, respectively.

  13. Irradiated bivalve mollusks: Use of EPR spectroscopy for identification and dosimetry

    Science.gov (United States)

    Alberti, Angelo; Chiaravalle, Eugenio; Fuochi, Piergiorgio; Macciantelli, Dante; Mangiacotti, Michele; Marchesani, Giuliana; Plescia, Elena

    2011-12-01

    High energy radiation treatment of foodstuff for microbial control and shelf-life extension is being used in many countries. However, for consumer protection and information, the European Union has adopted the Directives 1999/2/EC and 1999/3/EC to harmonize the rules concerning the treatment and trade of irradiated foods in EU countries. Among the validated methods to detect irradiated foods the EU directives also include Electron Paramagnetic Resonance (EPR/ESR) spectroscopy.We describe herein the use of EPR for identification of four species of bivalve mollusks, i.e. brown Venus shells (Callista chione), clams (Tapes semidecussatus), mussels (Mytilus galloprovincialis) and oysters (Ostrea edulis) irradiated with 60Co γ-rays. EPR could definitely identify irradiated seashells due to the presence of long-lived free radicals, primarily CO2-, CO33-, SO2- and SO3- radical anions. The presence of other organic free radicals, believed to originate from conchiolin, a scleroprotein present in the shells, was also ascertained. The use of one of these radicals as a marker for irradiation of brown Venus shells and clams can be envisaged. We also propose a dosimetric protocol for the reconstruction of the administered dose in irradiated oysters.

  14. The 1st Nuclear Test in the former USSR of 29 August 1949: Comparison of individual dose estimates by modeling with EPR retrospective dosimetry and luminescence retrospective dosimetry data for Dolon village, Kazakhstan

    Energy Technology Data Exchange (ETDEWEB)

    Stepanenko, V.F. [Medical Radiological Research Center of RAMS, 4 Korolev Str., Obninsk 249036 (Russian Federation); Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan)], E-mail: mrrc@obninsk.ru; Hoshi, M. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan); Ivannikov, A.I. [Medical Radiological Research Center of RAMS, 4 Korolev Str., Obninsk 249036 (Russian Federation); Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan); Bailiff, I.K. [Luminescence Dating and Dosimetry Laboratory, University of Durham, South Road, Durham, DHI 3LE (United Kingdom); Zhumadilov, K. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan); Skvortsov, V.G. [Medical Radiological Research Center of RAMS, 4 Korolev Str., Obninsk 249036 (Russian Federation); Argembaeva, R. [Scientifical Research Institute for Radiation Medicine, 258, Gagarina Str., P.B. 49, Semipalatinsk 490026 (Kazakhstan); Tsyb, A.F. [Medical Radiological Research Center of RAMS, 4 Korolev Str., Obninsk 249036 (Russian Federation)

    2007-07-15

    Three methods of individual dose reconstruction, namely dose calculations based on the available archive data and on the individual questioning of inhabitants, EPR dosimetry in human tooth enamel, and retrospective luminescence dosimetry (RLD) with quartz inclusions in the bricks were applied for assessment of accumulated external doses in Dolon village (Kazakhstan), which is one of the most affected settlements as a result of 29.08.1949 nuclear test at Semipalatinsk nuclear test site. Dose values obtained by EPR and RLD methods were compared with computed dose values. The available data on soil contamination with {sup 137}Cs and {sup 239+240}Pu in the vicinity and inside Dolon village were used for interpretation of the results of comparison. Based on a calculated value of 2260 mGy for the dose in the air along the central axis of the trace located NW of Dolon, the doses in the air over whole village and for the south-eastern part of the village containing the RLD sampling points were estimated as 775{+-}40 and 645{+-}70mGy, respectively, the latter correlates well with the RLD dose value of 460{+-}92mGy. The 'upper level' of the mean 'shielding and behavior' factor of dose reduction for inhabitants of Dolon village was estimated as 0.28{+-}0.07; this was performed by comparing the individual EPR tooth enamel doses with the calculated mean dose for the settlement. The individual dose estimates by EPR dosimetry were compared with individual dose values obtained by modeling. Uncertainties of the calculated individual doses were evaluated using Monte Carlo simulations. The individual dose estimates by EPR method are lower in comparison with mean computed doses and with RLD data, but they are in a good consistency with computed individual dose values in Dolon village based on the results of individual questioning with account of individual 'shielding and behavior' factors.

  15. Analysis behaviour of free radicals produced by ionizing radiations in human blood by EPR for biological dosimetry in patients; Analisis del comportamiento de los radicales libre en la radiolisis de la sangre por EPR para dosimetria biologia en pacientes

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza, O. O.; Almanza, A.; Plazas, M. M. C.

    2006-07-01

    In this work is analyzed the biological dosimetry of the free radicals produced by ionizing radiations in human blood obtained by EPR and the biological behaviour of samples In-Vitro, with Rh: O+, in tubes with EDTA (Acid Etilen Diamino Tetracetic) the samples was extracted of the main investigator, these samples were radiated with gammas of ''60Co of a Theratron 780 between plates of PMMA to a depth of Z{sub m}ax of 0.5 cm and between doses 1 to 25 Gy. In these results the behaviors of signal the free radicals presented a increasing a their intensity depending on applied dose, of equal way are results of the biologic dosimetry displayed in sanguineous populations like. White Globules, Red. Platelets etc, to being compared with Resonance Paramagnetic Electronic (EPR). The results show changes in sanguineous populations in high doses (D>10 Gy) in the case of lymphocytes, granulocitos, macusanita, plaquetas, hemoglobina, haematocrit with change similarly in medium and low doses (D>10Gy) in linfocites, platelets, granulocytes, monocytes and the haematocrit. A sanguineous sample without radiating analyzes by EPR giving the presence of signals with values of g=2.13 2,41 in blood. For the first certain value of g authors have associated it to free radicals like: globin (Fe(IV)=0) or Cu''+ incorporated to the ceruloplasmin molecule. (Author)

  16. Dosimetry of an accident in mixed field (neutrons, photons) using the spectrometry by electronic paramagnetic resonance(EPR); Dosimetrie d'accident en champ mixte (neutrons, photons) utilisant la spectrometrie par resonance paramagnetique electronique (RPE)

    Energy Technology Data Exchange (ETDEWEB)

    Herve, M.L

    2006-03-15

    In a radiological accident, the assessment of the dose received by the victim is relevant information for the therapeutic strategy. Two complementary dosimetric techniques based on physical means are used in routine practice in the laboratory: EPR spectroscopy performed on materials removed from the victim or gathered from the vicinity of the victim and Monte Carlo calculations. EPR dosimetry, has been used successfully several times in cases of photon or electron overexposures. Accidental exposure may also occur with a neutron component. The aim of this work is to investigate the potentiality of EPR dosimetry for mixed photon and neutron field exposure with different organic materials (ascorbic acid, sorbitol, glucose, galactose, fructose, mannose, lactose and sucrose). The influence of irradiation parameters (dose, dose rate, photon energy) and of environmental parameters (temperature of heating, light exposure) on the EPR signal amplitude was studied. To assess the neutron sensitivity, the materials were exposed to a mixed radiation field of experimental reactors with different neutron to photon ratios. The relative neutron sensitivity was found to range from 10% to 43% according to the materials. Prior knowledge of the ratio between the dose in samples measured by EPR spectrometry and organ or whole body dose obtained by calculations previously performed for these different configurations, makes it possible to give a first estimation of the dose received by the victim in a short delay. The second aim of this work is to provide data relevant for a quick assessment of the dose distribution in case of accidental overexposure based on EPR measurements performed on one or several points of the body. The study consists in determining by calculation the relation between the dose to the organs and whole body and the dose to specific points of the body, like teeth, bones or samples located in the pockets of victim clothes, for different external exposures corresponding

  17. Dose response of xylitol and sorbitol for EPR retrospective dosimetry with applications to chewing gum.

    Science.gov (United States)

    Israelsson, A; Gustafsson, H; Lund, E

    2013-04-01

    The purpose of this investigation was to study the radiation-induced electron paramagnetic resonance signal in sweeteners xylitol and sorbitol for use in retrospective dosimetry. For both sweeteners and chewing gum, the signal changed at an interval of 1-84 d after irradiation with minimal changes after 4-8 d. A dependence on storage conditions was noticed and the exposure of the samples to light and humidity was therefore minimised. Both the xylitol and sorbitol signals showed linearity with dose in the measured dose interval, 0-20 Gy. The dose-response measurements for the chewing gum resulted in a decision threshold of 0.38 Gy and a detection limit of 0.78 Gy. A blind test illustrated the possibility of using chewing gums as a retrospective dosemeter with an uncertainty in the dose determination of 0.17 Gy (1 SD).

  18. Ir-192 HDR transit dose and radial dose function determination using alanine/EPR dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Calcina, Carmen S Guzman [Departamento de FIsica e Matematica, FFCLRP, Universidade de Sao Paulo, Av Bandeirantes 3900, 14040-901, Ribeirao Preto, SP (Brazil); Almeida, Adelaide de [Departamento de FIsica e Matematica, FFCLRP, Universidade de Sao Paulo, Av Bandeirantes 3900, 14040-901, Ribeirao Preto, SP (Brazil); Rocha, Jose R Oliveira [Setor de FIsica Medica-CEB-UNICAMP e Setor de Radioterapia-CAISM-UNICAMP (Brazil); Abrego, Felipe Chen [Departamento de FIsica e Matematica, FFCLRP, Universidade de Sao Paulo, Av Bandeirantes 3900, 14040-901, Ribeirao Preto, SP (Brazil); Baffa, Oswaldo [Departamento de FIsica e Matematica, FFCLRP, Universidade de Sao Paulo, Av Bandeirantes 3900, 14040-901, Ribeirao Preto, SP (Brazil)

    2005-03-21

    Source positioning close to the tumour in high dose rate (HDR) brachytherapy is not instantaneous. An increment of dose will be delivered during the movement of the source in the trajectory to its static position. This increment is the transit dose, often not taken into account in brachytherapeutic treatment planning. The transit dose depends on the prescribed dose, number of treatment fractions, velocity and activity of the source. Combining all these factors, the transit dose can be 5% higher than the prescribed absorbed dose value (Sang-Hyun and Muller-Runkel, 1994 Phys. Med. Biol. 39 1181-8, Nath et al 1995 Med. Phys. 22 209-34). However, it cannot exceed this percentage (Nath et al 1995). In this work, we use the alanine-EPR (electron paramagnetic resonance) dosimetric system using analysis of the first derivative of the signal. The transit dose was evaluated for an HDR system and is consistent with that already presented for TLD dosimeters (Bastin et al 1993 Int. J. Radiat. Oncol. Biol. Phys. 26 695-702). Also using the same dosimetric system, the radial dose function, used to evaluate the geometric dose degradation around the source, was determined and its behaviour agrees better with those obtained by Monte Carlo simulations (Nath et al 1995, Williamson and Nath 1991 Med. Phys. 18 434-48, Ballester et al 1997 Med. Phys. 24 1221-8, Ballester et al 2001 Phys. Med. Biol. 46 N79-90) than with TLD measurements (Nath et al 1990 Med. Phys. 17 1032-40)

  19. Dosimetry in non-homogeneous media with alanine/EPR mini dosemeters and simulation with PENELOPE Monte Carlo code;Dosimetria em meios nao-homogeneos com minidosimetros de alanina/EPR e simulacao Monte Carlo com o codigo PENELOPE

    Energy Technology Data Exchange (ETDEWEB)

    Vega Ramirez, J.L.; Chen, F.; Nicolucci, P.; Baffa, O. [Universidade de Sao Paulo (FFCLRP/USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica e Matematica

    2009-07-01

    The dosimetric system of L-alanine mini dosimeter and K-Band EPR spectrometer was tested for the dosimetry in non-homogeneous media through the determination of the Percentage Depth Dose (PDD) curve for a small radiation field. The alanine mini dosimeters were produced by mechanical pressure of a mixture of L-alanine (95%) and PVA (5%) to nominal dimensions of 1 mm diameter and 3 mm length and 3 - 4 mg. For detecting the EPR signal of the mini dosimeters irradiated to 25 Gy, a K-Band (24 GHz) spectrometer was used. The dosimeters were irradiated in a {sup 60}Co radiotherapy unit using 80 cm source skin distance and field sizes of 2.5 x 2.5 cm{sup 2}. The inhomogeneous phantom consisted of acrylic and cork sheets of 30 x 30 x 1 cm{sup 3}; six cork sheets were sandwiched between five and nine acrylic sheets, which were placed at the top and bottom regions respectively. PDD curves with radiographic film and PENELOPE simulation were also determined. The PDD results for alanine mini dosimeters agreed better than 5.9% with film and PENELOPE. (author)

  20. BiodosEPR-2006 Meeting: Acute dosimetry consensus committee recommendations on biodosimetry applications in events involving uses of radiation by terrorists and radiation accidents

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, George A. [U.S. Department of Health and Human Services, Office of Preparedness and Emergency Operations, 200 Independence Avenue, SW, Room 403B-1, Washington, DC 20201 (United States); Swartz, Harold M. [Dept. of Radiology and Physiology Dept., Dartmouth Medical School, HB 7785, Vail 702, Rubin 601, Hanover, NH 03755 (United States); Amundson, Sally A. [Center for Radiological Research, Columbia University Medical Center, 630 W. 168th Street, VC11-215, New York, NY 10032 (United States); Blakely, William F. [Armed Forces Radiobiology Research Inst., 8901 Wisconsin Avenue, Bethesda, MD 20889-5603 (United States)], E-mail: blakely@afrri.usuhs.mil; Buddemeier, Brooke [Science and Technology, U.S. Department of Homeland Security, Washington, DC 20528 (United States); Gallez, Bernard [Biomedical Magnetic Resonance Unit and Lab. of Medicinal Chemistry and Radiopharmacy, Univ. Catholique de Louvain, Brussels (Belgium); Dainiak, Nicholas [Dept. of Medicine, Bridgeport Hospital, 267 Grant Street, Bridgeport, CT 06610 (United States); Goans, Ronald E. [MJW Corporation, 1422 Eagle Bend Drive, Clinton, TN 37716-4029 (United States); Hayes, Robert B. [Remote Sensing Lab., MS RSL-47, P.O. Box 98421, Las Vegas, NV 89193 (United States); Lowry, Patrick C. [Radiation Emergency Assistance Center/Training Site (REAC/TS), Oak Ridge Associated Universities, P.O. Box 117, Oak Ridge, TN 37831-0117 (United States); Noska, Michael A. [Food and Drug Administration, FDA/CDRH, 1350 Piccard Drive, HFZ-240, Rockville, MD 20850 (United States); Okunieff, Paul [Dept. of Radiation Oncology (Box 647), Univ. of Rochester, 601 Elmwood Avenue, Rochester, NY 14642 (United States); Salner, Andrew L. [Helen and Harry Gray Cancer Center, Hartford Hospital, 80 Seymour Street, Hartford, CT 06102 (United States); Schauer, David A. [National Council on Radiation Protection and Measurements, 7910 Woodmont Avenue, Suite 400, Bethesda, MD 20814-3095 (United States)] (and others)

    2007-07-15

    In the aftermath of a radiological terrorism incident or mass-casualty radiation accident, first responders and receivers require prior guidance and pre-positioned resources for assessment, triage and medical management of affected individuals [NCRP, 2005. Key elements of preparing emergency responders for nuclear and radiological terrorism. NCRP Commentary No. 19, Bethesda, Maryland, USA]. Several recent articles [Dainiak, N., Waselenko, J.K., Armitage, J.O., MacVittie, T.J., Farese, A.M., 2003. The hematologist and radiation casualties. Hematology (Am. Soc. Hematol. Educ. Program) 473-496; Waselenko, J.K., MacVittie, T.J., Blakely, W.F., Pesik, N., Wiley, A.L., Dickerson, W.E., Tsu, H., Confer, D.L., Coleman, C.N., Seed, T., Lowry, P., Armitage, J.O., Dainiak, N., Strategic National Stockpile Radiation Working Group, 2004. Medical management of the acute radiation syndrome: recommendations of the Strategic National Stockpile Radiation Working Group. Ann. Intern. Med. 140(12), 1037-1051; Blakely, W.F., Salter, C.A., Prasanna, P.G., 2005. Early-response biological dosimetry-recommended countermeasure enhancements for mass-casualty radiological incidents and terrorism. Health Phys. 89(5), 494-504; Goans, R.E., Waselenko, J.K., 2005. Medical management of radiation casualties. Health Phys. 89(5), 505-512; Swartz, H.M., Iwasaki, A., Walczak, T., Demidenko, E., Salikhov, I., Lesniewski, P., Starewicz, P., Schauer, D., Romanyukha, A., 2005. Measurements of clinically significant doses of ionizing radiation using non-invasive in vivo EPR spectroscopy of teeth in situ. Appl. Radiat. Isot. 62, 293-299; . Acute radiation injury: contingency planning for triage, supportive care, and transplantation. Biol. Blood Marrow Transplant. 12(6), 672-682], national [. Management of persons accidentally contaminated with radionuclides. NCRP Report No. 65, Bethesda, Maryland, USA; . Management of terrorist events involving radioactive material. NCRP Report No. 138, Bethesda, Maryland

  1. Tooth enamel EPR dosimetry of neutrons: Enhancement of the apparent sensitivity at irradiation in the human head phantom

    Energy Technology Data Exchange (ETDEWEB)

    Khailov, A.M. [Medical Radiological Research Center, Korolyov str., 4, Obninsk 249032 (Russian Federation); Ivannikov, A.I. [Medical Radiological Research Center, Korolyov str., 4, Obninsk 249032 (Russian Federation)], E-mail: ivannikov@mrrc.obninsk.ru; Tikunov, D.D.; Skvortsov, V.G.; Stepanenko, V.F. [Medical Radiological Research Center, Korolyov str., 4, Obninsk 249032 (Russian Federation); Zhumadilov, K.; Tanaka, K.; Endo, S.; Hoshi, M. [Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan)

    2007-07-15

    Induction of the EPR signal in tooth enamel at irradiation by the neutrons produced by a generator with maximal energy of 0.8 MeV in the air and in the human head phantom was investigated. Neutron and photon tissue absorbed doses in the mixed radiation field were determined experimentally and calculated using the Monte-Carlo method. It is shown that the EPR signal response of enamel to neutrons relative to the tissue dose is (2{+-}2)% of the appropriate value for {sup 60}Co gamma radiation. At irradiation in the human head phantom, the EPR signal response relatively to the input neutron tissue dose near the surface of the phantom (apparent EPR sensitivity to neutrons) increases to (14{+-}1)%. The observed EPR signal enhancement is caused by absorption in enamel of the secondary photons produced at H(n,{gamma})H{sup 2}, E{sub {gamma}}=2.23MeV reaction in the material of the phantom.

  2. Review of the dose-to-water energy dependence of alanine and lithium formate EPR dosimeters and LiF TL-dosimeters - Comparison with Monte Carlo simulations

    Energy Technology Data Exchange (ETDEWEB)

    Waldeland, Einar, E-mail: einar.waldeland@oslo-universitetssykehus.no [Department of Medical Physics, Oslo University Hospital, Norwegian Radium Hospital, P.O. Box 4953 Nydalen, N-0424 Oslo (Norway); Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Malinen, Eirik [Department of Medical Physics, Oslo University Hospital, The Norwegian Radium Hospital, P.O. Box 4953 Nydalen, N-0424 Oslo (Norway); Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway)

    2011-09-15

    The dose-to-water energy dependence may be defined as the dosimeter reading per absorbed dose to water for a given radiation beam relative to that for {sup 60}Co {gamma} rays. The purpose of this work was to review the literature on the dose-to-water energy dependence of lithium formate and alanine EPR dosimeters and LiF:Mg,Ti TL-dosimeters for clinical beam qualities and to compare the findings with Monte Carlo simulations. Monte Carlo simulations of the energy dependence of lithium formate and alanine EPR dosimeters and LiF:Mg,Ti TL-dosimeters were performed using the EGSnrc code. The following common clinical radiation qualities were applied: 4-24 MV photons, 4-20 MeV electrons, 50-200 kV{sub p} X-rays, {sup 192}Ir {gamma} rays, and {sup 60}Co {gamma} rays as the reference. All dosimeter materials showed measured and Monte Carlo simulated energy responses around unity for MV photons, electrons and {sup 192}Ir {gamma} rays, except LiF TL-dosimeters which showed an average underresponse of approximately 3% for electrons. For medium energy X-rays (50-200 kV{sub p}), LiF displayed an increasing overresponse with decreasing energy to a maximum of about 40% for 50 kV{sub p} X-rays. The two EPR dosimeter materials showed decreasing energy response with decreasing X-ray energy, but lithium formate was less dependent on energy than alanine. Comparisons between Monte Carlo simulations and measurements revealed some deviations for medium energy X-rays, which may be due to LET-effects caused by low energy electrons. In conclusion, lithium formate is the dosimeter material with the lowest energy dependence over a wide range of clinically relevant radiation qualities, which clearly is advantageous for accurate dosimetry.

  3. DOSIMETRY

    CERN Multimedia

    Service de dosimétrie individuelle

    2000-01-01

    From the distribution Novembre/Decembre 2000 (film colour green), the people who worked in LEP experiments and who have not announced their participation to LEP dismantling or new activities in another experiment or group will be taken out from the regular distribution list of the Individual Dosimetry Service. Please contact Individual Dosimetry Service, tel. 72155 or e-mail to Jeannine.Fraisse@cern.ch We inform all staff and users under regular dosimetric control that the dosimeters for the monitoring period SEPTEMBER/OCTOBER will be available from their usual dispatchers on the 1st of September 2000. Please have your films changed before the 12th of September. The colour of the dosimeter valid in SEPTEMBER/OCTOBER is RED. The service will be closed exceptionally on Friday 8 September.

  4. DOSIMETRY

    CERN Multimedia

    2001-01-01

    From the month of May on, the neutron dosimeter will be worn in an extra package distinct from the usual film-badge. We will give you more ample information in Weekly Bulletin No. 18/2001 of April 30, 2001. In the week following Easter (17 - 20. 4. 2001) the Individual Dosimetry Service will be opened in the mornings from 8:30 to 11:30 h only. The Service will be closed on April 30.

  5. Preliminary study of window silicate glass powder for EPR dosimetry with 10-MeV electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ramezani Moghaddam, Ali, E-mail: ali-ramezani@aut.ac.ir [Department of Physics and Nuclear Engineering, AmirKabir University of Technology (Iran, Islamic Republic of); Shamsaei, Mojtaba [Department of Physics and Nuclear Engineering, AmirKabir University of Technology (Iran, Islamic Republic of); Amraei, Reza [Radiation Applications Research School, Nuclear Science and Technology Research Institute, Yazd (Iran, Islamic Republic of)

    2012-03-01

    Window silicate glass powder has been evaluated as a possible high dose dosimeter using EPR (Electron Paramagnetic Resonance) technique. In this work window glass powder with maximum dimension of 700 {mu}m was irradiated with 10 MeV electrons with doses ranging from 580 Gy to 46.52 kGy. The EPR response of the irradiated samples showed a linear behavior to applied doses up to 8 kGy. The EPR spectra of NBOHC (Non-Bonding Oxygen Hole Center) was found at g{sub 1} = 2.0092 {+-} 0.0001 and g{sub 2} = 2.0042 {+-} 0.0001. The line widths of all spectra were found to be the same. Finally, the thermal fading of EPR intensity was studied for 70 days and showed a sharp decline on the first day. This fading continued up to almost 15 days and then the slope of the decay-curve tended to gradual changes up to 50 days. Afterwards, it presented a fairly constant value with time and a predictable stability was achieved.

  6. EPR study of the formation of radicals in PP with antioxidants irradiated with gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Silva, P. [Instituto Venezolano de Investigaciones Cientificas, Centro de Fisica, Carretera Panamericana Km. 11, Caracas 1020-A (Venezuela)], E-mail: silva@ivic.ve; Albano, C. [Instituto Venezolano de Investigaciones Cientificas, Centro de Quimica, Universidad Central de Venezuela, Facultad de Ingenieria (Venezuela); Perera, R. [Departamento de Mecanica, Universidad Simon Bolivar (Venezuela)

    2007-12-15

    The behavior of different compounds of polypropylene (PP) with stabilizers such as buthyl-hydroxy-toluene (BHT), Chimassorb 944 (Hals) (CHIM), and a copolymer of styrene-butadiene-styrene (SBS) was studied using electron paramagnetic resonance (EPR). A characteristic spectra for pure PP irradiated in air was obtained for all the samples just after being irradiated [M. Dole, The Radiation Chemistry of Macromolecules, Vol. 2, Academic Press, 1973]. A change in the lineshape of the spectra from a pure PP's EPR signal to that of nitroxyl radical as a function of time was observed. The total free radical concentration (TFRC) decayed until approximately 800 h in the PP-HALS and until around 2000 h in all other cases, when the TFRC began to increase in all the cases, except in that of PP-BHT. In this last case, the EPR signal was not detectable after 4000 h. The BHT and the SBS diluted the free radical concentrations, being them smaller when they are present. The behavior observed in all the samples is consistent with the formation of nitroxyl radicals by gamma rays.

  7. Absolute calibration of the Gamma Knife{sup ®} Perfexion™ and delivered dose verification using EPR/alanine dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Hornbeck, Amaury, E-mail: amauryhornbeck@gmail.com, E-mail: tristan.garcia@cea.fr; Garcia, Tristan, E-mail: amauryhornbeck@gmail.com, E-mail: tristan.garcia@cea.fr [CEA, LIST, Laboratoire National Henri Becquerel, 91191 Gif-sur-Yvette Cedex (France); Cuttat, Marguerite; Jenny, Catherine [Radiotherapy Department, Medical Physics Unit, University Hospital Pitié-Salpêtrière, 75013 Paris (France)

    2014-06-15

    Purpose: Elekta Leksell Gamma Knife{sup ®} (LGK) is a radiotherapy beam machine whose features are not compliant with the international calibration protocols for radiotherapy. In this scope, the Laboratoire National Henri Becquerel and the Pitié-Salpêtrière Hospital decided to conceive a new LKG dose calibration method and to compare it with the currently used one. Furthermore, the accuracy of the dose delivered by the LGK machine was checked using an “end-to-end” test. This study also aims to compare doses delivered by the two latest software versions of the Gammaplan treatment planning system (TPS). Methods: The dosimetric method chosen is the electron paramagnetic resonance (EPR) of alanine. Dose rate (calibration) verification was done without TPS using a spherical phantom. Absolute calibration was done with factors calculated by Monte Carlo simulation (MCNP-X). For “end-to-end” test, irradiations in an anthropomorphic head phantom, close to real treatment conditions, are done using the TPS in order to verify the delivered dose. Results: The comparison of the currently used calibration method with the new one revealed a deviation of +0.8% between the dose rates measured by ion chamber and EPR/alanine. For simple fields configuration (less than 16 mm diameter), the “end-to-end” tests showed out average deviations of −1.7% and −0.9% between the measured dose and the calculated dose by Gammaplan v9 and v10, respectively. Conclusions: This paper shows there is a good agreement between the new calibration method and the currently used one. There is also a good agreement between the calculated and delivered doses especially for Gammaplan v10.

  8. EPR study of complex formation between copper (II) ions and sympathomimetic amines in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Preoteasa, E.A. [Inst. of Atomic Physics, IFIN, Bucharest (Romania); Duliu, O.G.; Grecu, V.V. [Bucharest, Univ. (Romania). Dept. of Atomic and Nuclear Physics

    1997-07-01

    The complex formation between sympathomimetic amines (SA): adrenaline (AD), noradrenaline (NA), dopamine (DA), ephedrine (ED) and p-tyramine (pTA), and Cu(II) ion in aqueous solution has been studied by X-band EPR at room temperature. Excepting pTA, all investigated SA yielded two types of complexes in different pH domains. All complexes consistent with a ligand fields having a distorted octahedral symmetry, i.e., hexacoordination of Cu(II). The covalence coefficient calculated from the isotropic g and A values has shown strong ionic sigma-type ligand bonds. A structural model with the Cu(II) ion bound by four catecholic O(hydroxy) atoms for the low pH complexes of AD, NA and DA is proposed. For the high pH complexes of the former compounds as well as for both Ed complexes, the authors suppose Cu(II) bound by two N (amino) and two O (hydroxy) atoms. The spectra are consistent to water binding on the longitudinal octahedron axis in all compounds excepting the high pH complex of Ed, where OH2- ions are bound. Possible implications for the SA-cell receptors interactions are discussed.

  9. Formation of cholesterol bilayer domains precedes formation of cholesterol crystals in cholesterol/dimyristoylphosphatidylcholine membranes: EPR and DSC studies.

    Science.gov (United States)

    Mainali, Laxman; Raguz, Marija; Subczynski, Witold K

    2013-08-01

    Saturation-recovery EPR along with DSC were used to determine the cholesterol content at which pure cholesterol bilayer domains (CBDs) and cholesterol crystals begin to form in dimyristoylphosphatidylcholine (DMPC) membranes. To preserve compositional homogeneity throughout the membrane suspension, lipid multilamellar dispersions were prepared using a rapid solvent exchange method. The cholesterol content increased from 0 to 75 mol %. With spin-labeled cholesterol analogues, it was shown that the CBDs begin to form at ~50 mol % cholesterol. It was confirmed by DSC that the cholesterol solubility threshold for DMPC membranes is detected at ~66 mol % cholesterol. At levels above this cholesterol content, monohydrate cholesterol crystals start to form. The major finding is that the formation of CBDs precedes formation of cholesterol crystals. The region of the phase diagram for cholesterol contents between 50 and 66 mol % is described as a structured one-phase region in which CBDs have to be supported by the surrounding DMPC bilayer saturated with cholesterol. Thus, the phase boundary located at 66 mol % cholesterol separates the structured one-phase region (liquid-ordered phase of DMPC with CBDs) from the two-phase region where the structured liquid-ordered phase of DMPC coexists with cholesterol crystals. It is likely that CBDs are precursors of monohydrate cholesterol crystals.

  10. EPR techniques for space biodosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Haskell, E.; Hayes, R.; Kenner, G.; Sholom, S.; Chumak, V.

    1996-12-31

    Retrospective dosimetry of tooth enamel has become an increasingly complex and difficult discipline to undertake while still attaining accuracy. The paper provides a review of the major obstacles, advances and pertinent phenomenon associated with low level retrospective dosimetry of human tooth enamel. Also covered is the many sources of error in EPR dosimetry, their potential solutions, as well as the different analysis and scanning techniques in use with their prospective pros and cons. Prospective directions for new approaches, methods, and instruments are also reviewed.

  11. 3-Pyridylmethanol vs. N,N‧-diethylnicotinamide in copper(II) complex formation - A comparative EPR study

    Science.gov (United States)

    Husáriková, L.; Repická, Z.; Valigura, D.; Valko, M.; Mazúr, M.

    2013-10-01

    Copper(II) complexes, formed from 4-chlorosalicylic acid anion A (A = 4-Clsal-), different copper(II) salts (Cu(ac)2 or CuSO4) and different N-donor ligands B (B = 3-pyridylmethanol (ron) or N,N'-diethylnicotinamide (denia)) with varying N-donor ligand-to-metal ratio (x), were studied by EPR spectroscopy in the frozen water/methanol (1:3 v/v) solutions. The number of ligand B molecules coordinated to Cu(II) central ion was determined from the nitrogen perpendicular and parallel superhyperfine splitting multiplets of Cu(II) EPR spectra. It was found for both N-donor ligands: (i) At lower ligand B concentrations (x = 1, 2), [CuB] and/or [CuB2] species having one and/or two molecules of ligands B in equatorial position were dominant. The dominant ternary complex particles were [CuA2B2] species. (ii) At higher ligand B concentrations (x ⩾ 4) the formation of [CuB3] and/or [CuB4] species having three and/or four molecules of ligands B in equatorial position was confirmed. Such information is not possible to get from Cu(II) EPR spectra of powdered samples of given copper(II) complexes.

  12. EPFR Formation from Phenol adsorption on Al2O3 and TiO2: EPR and EELS studies

    Science.gov (United States)

    Patterson, Matthew C.; Keilbart, Nathan D.; Kiruri, Lucy W.; Thibodeaux, Chad A.; Lomnicki, Slawo; Kurtz, Richard L.; Poliakoff, E. D.; Dellinger, Barry; Sprunger, Phillip T.

    2013-01-01

    We have examined the formation of environmentally persistent free radicals (EPFRs) from phenol over alumina and titania using both powder and single-crystal samples. Electron paramagnetic resonance (EPR) studies of phenol adsorbed on metal oxide powders indicates radical formation on both titania and alumina, with both oxides forming one faster-decaying species (lifetime on the order of 50-100 hours) and one slower-decayng species (lifetimes on the order of 1000 hours or more). Electron energy loss spectroscopy (EELS) measurements comparing physisorbed phenol on single-crystal TiO2(110) to phenoxyl radicals on the same substrate indicate distinct changes in the π-π* transitions from phenol after radical formation. The identical shifts are observed from EELS studies of phenoxyl radicals on ultrathin alumina grown on NiAl(110), indicating that this shift in the π-π* transition may be taken as a general hallmark of phenoxyl radical formation. PMID:24443627

  13. Chemical dosimetry system for γ-ray irradiation based on the formation of phenol from aqueous benzene solutions.

    Science.gov (United States)

    Takeda, Kazuhiko

    2011-01-01

    A chemical dosimetry system based on the radiochemical formation of phenol from aqueous benzene solutions was applied to measure the intensity of γ-ray irradiation. Using a simple and sensitive isocratic fluorometric HPLC system, radiochemically generated phenol was determined. The radiochemical formation of phenol was linear up to 100 Gy and the lower limit of detection calculated from the detection limits of phenol was estimated to be 7 mGy. The phenol formation rates were not affected by the oxygen saturation. The chemical dosimetry system investigated in this study was sensitive and was easier to use than traditional chemical dosimeters.

  14. The EPR reactor; Le reacteur EPR

    Energy Technology Data Exchange (ETDEWEB)

    Lacoste, A.C.; Dupuy, Ph.; Gupta, O.; Perez, J.R.; Emond, D. [Direction Generale de la Surete Nucleaire et de la Radioprotection, 75 - Paris (France); Cererino, G.; Rousseau, J.M.; Jeffroy, F.; Evrard, J.M. [Institut de Radioprotection et de Surete Nucleaire (IRSN), Dir. de la Surete des Reacteurs, 92 - Clamart (France); Seiler, J.M. [CEA Cadarache (DEN/DTN), 13 - Saint-Paul-lez-Durance (France); Azarian, G. [FRAMATOME ANP, 92 - Paris-La-Defence (France); Chaumont, B. [Institut de Radioprotection et de Surete Nucleaire (IRSN/DSR), 92 - Fontenay-aux-Roses (France); Dubail, A. [Electricite de France (EDF), 78 - Chatou (France); Fischer, M. [Framatome ANP GmbH, Erlangen (Germany); Tiippana, P.; Hyvarinen, J. [Stuk, Autorite de Surete Nucleaire et de Radioprotection (Finland); Zaleski, C.P.; Meritet, S. [Paris-9 Univ. Dauphine, Centre de Geopolitique de l' Energie et des Matieres Premieres, 75 (France); Iglesias, F.; Vincent, C. [Direction Generale de l' Energie et des Matieres Premieres, 75 - Paris (France); Massart, S.; Graillat, G. [Electricite de France (EDF), 75 - Paris (France); Esteve, B. [AREVA/Framatome, 75 - Paris (France); Mansillon, Y. [Commission Nationale de Debat Public, 75 - Paris (France); Gatinol, C. [Assemblee Nationale, 75 - Paris (France); Carre, F. [CEA, Dir. de Programme Systemes du Futur, France (France)

    2005-05-01

    This document reviews economical and environmental aspects of the EPR project. The following topics are discussed: role and point of view of the French Nuclear Safety Authority on EPR, control of design and manufacturing of EPR by the French Nuclear Safety Authority, assessment by IRSN of EPR safety, research and development in support of EPR, STUK safety review of EPR design, standpoint on EPR, the place of EPR in the French energy policy, the place of EPR in EDF strategy, EPR spearhead of nuclear rebirth, the public debate, the local stakes concerning the building of EPR in France at Flamanville (Manche) and the research on fourth generation reactors. (A.L.B.)

  15. Alanine-EPR dosimetry for measurements of ionizing radiation absorbed doses in the range 0.5-10 kGy

    CERN Document Server

    Peimel-Stuglik, Z

    2001-01-01

    The usefulness of two, easy accessible alanine dosimeters (ALANPOL from IChTJ and foil dosimeter from Gamma Service, Radeberg, Germany) to radiation dose measurement in the range of 0.5-10 kGy, were investigated. In both cases, the result of the test was positive. The foil dosemeter from Gamma Service is recommended for dose distribution measurements in fantoms or products, ALANPOL - for routine measurements. The EPR-alanine method based on the described dosimeters can be successfully used, among others, in the technology of radiation protection of food.

  16. Direct detection of second harmonic and its use in alanine/EPR dosimetry; Deteccao direta do segundo harmonico e seu uso na dosimetria alanina/RPE

    Energy Technology Data Exchange (ETDEWEB)

    Chen, F.; Guzman, C.S.; Graeff, C.F.O.; Baffa, O. [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica e Matematica]. E-mail: chen@dfm.ffclrp.usp.br

    2001-07-01

    In this work, the possible use of the second harmonic EPR signal from irradiated alanine for low radiation dose ({approx}1 Gy) was explored, aiming applications to HDR brachytherapy and teletherapy. The second harmonic signal was directly detected after overmodulation. A batch of DL-alanine/paraffin small cylindrical pellets was made. A VARIAN E-4 X-Band EPR spectrometer with optimized operation parameters like microwave power and modulation amplitude to obtain a signal with the highest amplitude was used. The modulation frequency and modulation amplitude were 100 kHz and 1.25 mT (to overmodulate the signal) respectively. The second harmonic signal was directly detected at twice the modulation frequency. One group of dosimeters was irradiated with a {sup 192} Ir brachytherapy source and the other in a 10 MeV X-rays linear accelerator, both group at a dose range: 0.5 - 15 Gy. The second harmonic signal showed better resolution than the first harmonic one making possible a more easy localization of the signal. Moreover, for both types of radiation, the dose-response curve showed a good linear behavior for the dose range indicated. (author)

  17. Applications of EPR in radiation research

    CERN Document Server

    Lund, Anders

    2014-01-01

    Applications of EPR in Radiation Research is a multi-author contributed volume presented in eight themes: I. Elementary radiation processes (in situ and low temperature radiolysis, quantum solids); II: Solid state radiation chemistry (crystalline, amorphous and heterogeneous systems); III: Biochemistry, biophysics and biology applications (radicals in biomaterials, spin trapping, free-radical-induced DNA damage); IV: Materials science (polymeric and electronic materials, materials for treatment of nuclear waste, irradiated food); V: Radiation metrology (EPR-dosimetry, retrospective and medical

  18. Dosimetry; La dosimetrie

    Energy Technology Data Exchange (ETDEWEB)

    Le Couteulx, I.; Apretna, D.; Beaugerie, M.F. [Electricite de France (EDF), 75 - Paris (France)] [and others

    2003-07-01

    Eight articles treat the dosimetry. Two articles evaluate the radiation doses in specific cases, dosimetry of patients in radiodiagnosis, three articles are devoted to detectors (neutrons and x and gamma radiations) and a computer code to build up the dosimetry of an accident due to an external exposure. (N.C.)

  19. EPFR formation from phenol adsorption on Al{sub 2}O{sub 3} and TiO{sub 2}: EPR and EELS studies

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, Matthew C., E-mail: mpatt15@tigers.lsu.edu [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Keilbart, Nathan D., E-mail: kei07001@byui.edu [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Department of Mechanical Engineering, Brigham Young University-Idaho, Rexburg, ID 83460 (United States); Kiruri, Lucy W., E-mail: lkirur1@tigers.lsu.edu [Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 (United States); Thibodeaux, Chad A., E-mail: cthib19@tigers.lsu.edu [Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 (United States); Lomnicki, Slawo, E-mail: slomni1@lsu.edu [Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 (United States); Kurtz, Richard L., E-mail: rlkurtz@lsu.edu [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Poliakoff, E.D., E-mail: epoliak@lsu.edu [Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 (United States); Dellinger, Barry, E-mail: barryd@lsu.edu [Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 (United States); Sprunger, Phillip T., E-mail: phils@lsu.edu [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States)

    2013-08-30

    Highlights: ► EPR studies of phenol adsorption on titania and alumina show radical formation at 505 K. ► EELS of phenol/TiO{sub 2}(1 1 0) at 90 K show π–π{sup ∗} transitions from intact molecule. ► EELS of phenol/TiO{sub 2}(1 1 0) and phenol/alumina adsorbed at 525 K show shift in π–π{sup ∗}. ► Shifted π–π{sup ∗} on single crystal corresponds to radical formation conditions in EPR. - Abstract: We have examined the formation of environmentally persistent free radicals (EPFRs) from phenol over alumina and titania using both powder and single-crystal samples. Electron paramagnetic resonance (EPR) studies of phenol adsorbed on metal oxide powders indicates radical formation on both titania and alumina, with both oxides forming one faster-decaying species (lifetime on the order of 50–100 h) and one slower-decaying species (lifetimes on the order of 1000 h or more). Electron energy loss spectroscopy (EELS) measurements comparing physisorbed phenol on single-crystal TiO{sub 2}(1 1 0) to phenoxyl radicals on the same substrate indicate distinct changes in the π–π{sup ∗} transitions from phenol after radical formation. The identical shifts are observed from EELS studies of phenoxyl radicals on ultrathin alumina grown on NiAl(1 1 0), indicating that this shift in the π–π{sup ∗} transition may be taken as a general hallmark of phenoxyl radical formation.

  20. Study of EPR/ESR Dosimetry in Fingernails as a Method for Assessing Dose of Victims of Radiological Accidents/Incidents

    Science.gov (United States)

    2008-06-17

    peptide chains twisted in a left-handed coil and strengthened by sulfur bridges formed from cystine groups. The alpha keratin in fingernails has a...documented as the signal produced from the formation of radicals in fingernails after cutting, which is most intense on freshly-cut samples [82]. The...centered radicals with a characteristic spectrum [27]. The doublet splitting of about 8.5 G has been assigned to a proton in the unique cystine

  1. TL and EPR dating: some applications

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, S. [Institute of Physics, University of Sao Paulo, Sao Paulo (Brazil)

    2006-07-01

    The intensity of thermoluminescence light emitted by a crystal is a function of radiation dose. The number of defects or of radicals in a crystal or organic substances is also a function of radiation dose. Since such defects or radicals present EPR signals, the EPR intensity is also a function of radiation dose. These facts are basis for radiation dosimetry and can be applied in dating of archaeological potteries or other materials, as well as in dating geological substances such as sediments, caves speleothemes, animal teeth and bones. Recent investigation on sensitized quartz based dosimeters and dating calcite covering ancient wall painting to find early settlers in Brazil will be presented. (Author)

  2. Dosimetry of ionizing radiations by Electron paramagnetic resonance; Dosimetria de radiaciones ionizantes por resonancia paramagnetica electronica

    Energy Technology Data Exchange (ETDEWEB)

    Azorin N, J. [UAM-I, Av. San Rafael Atlixco 186, 09340 Mexico D.F. (Mexico)

    2005-07-01

    In this work, some historical and theoretical aspects about the Electron Paramagnetic Resonance (EPR), its characteristics, the resonance detection, the paramagnetic species, the radiation effects on inorganic and organic materials, the diagrams of the instrumentation for the EPR detection, the performance of an EPR spectrometer, the coherence among EPR and dosimetry and, practical applications as well as in the food science there are presented. (Author)

  3. Radiation dosimetry

    CERN Document Server

    Hine, Gerald J; Hine, Gerald J

    1956-01-01

    Radiation Dosimetry focuses on the advancements, processes, technologies, techniques, and principles involved in radiation dosimetry, including counters and calibration and standardization techniques. The selection first offers information on radiation units and the theory of ionization dosimetry and interaction of radiation with matter. Topics include quantities derivable from roentgens, determination of dose in roentgens, ionization dosimetry of high-energy photons and corpuscular radiations, and heavy charged particles. The text then examines the biological and medical effects of radiation,

  4. Metallomic EPR spectroscopy.

    Science.gov (United States)

    Hagen, Wilfred R

    2009-09-01

    Based on explicit definitions of biomolecular EPR spectroscopy and of the metallome, this tutorial review positions EPR in the field of metallomics as a unique method to study native, integrated systems of metallobiomolecular coordination complexes subject to external stimuli. The specific techniques of whole-system bioEPR spectroscopy are described and their historic, recent, and anticipated applications are discussed.

  5. Electron paramagnetic resonance dosimetry using synthetic hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kwon; Kim, Hwi Young; Ye, Sung Joon [Seoul National University, Seoul (Korea, Republic of); Hirata, Hiroshi [Hokkaido University, Sapporo (Japan); Park, Jong Min [Seoul National University Hospital, Seoul (Korea, Republic of)

    2014-11-15

    The victims exposed doses under 3.5-4.0 Gy have chance to survive if treated urgently. To determine the priority of treatment among a large number of victims, the triage – distinguishing patients who need an urgent treatment from who may not be urgent – is necessary based on radiation biodosimetry. A current gold standard for radiation biodosimetry is the chromosomal assay using human lymphocytes. But this method requires too much time and skilled labors to cover the mass victims in radiation emergencies. Electron paramagnetic resonance (EPR) has been known for its capability of quantifying radicals in matters. EPR dosimetry is based on the measurement of stable radiation-induced radicals in tooth enamel. Hydroxyapatite (HAP) (Ca10(PO4)6(OH)2) contained in tooth enamel is a major probe for radiation dose reconstruction. This HAP dosimetry study was performed using a novel EPR spectrometer in Hokkaido University, Japan. The EPR dose-response curve was made using HAP samples. The blind test using 250 cGy samples showed the feasibility of EPR dosimetry for the triage purpose.

  6. Hematological dosimetry. Dosimetrie hematologique

    Energy Technology Data Exchange (ETDEWEB)

    Fluery-Herard, A. (CEA Centre d' Etudes de Fontenay-aux-Roses, 92 (FR). Direction des Sciences du Vivant)

    1991-01-01

    The principles of hematological dosimetry after acute or protracted whole-body irradiation are reviewed. In both cases, over-exposure is never homogeneous and the clinical consequences, viz medullary aplasia, are directly associated with the mean absorbed dose and the seriousness and location of the overexposure. The main hematological data required to assess the seriousness of exposure are the following: repeated blood analysis, blood precursor cultures, as indicators of whole-body exposure; bone marrow puncture, medullary precursor cultures and medullary scintigraphy as indicators of the importance of a local over-exposure and capacity for spontaneous repair. These paraclinical investigations, which are essential for diagnosis and dosimetry, are also used for surveillance and for the main therapeutic issues.

  7. Dosimetry Service

    CERN Multimedia

    2006-01-01

    Cern Staff and Users can now consult their dose records for an individual or an organizational unit with HRT. Please see more information on our web page: http://cern.ch/rp-dosimetry Dosimetry Service is open every morning from 8.30 - 12.00. Closed in the afternoons. We would like to remind you that dosimeters cannot be sent to customers by internal mail. Short-term dosimeters (VCT's) must always be returned to the Service after the use and must not be left on the racks in the experimental areas or in the secretariats. Dosimetry Service Tel. 7 2155 Dosimetry.service@cern.ch http://cern.ch/rp-dosimetry

  8. Dosimetry for electron Intra-Operative RadioTherapy: Comparison of output factors obtained through alanine/EPR pellets, ionization chamber and Monte Carlo-GEANT4 simulations for IORT mobile dedicate accelerator

    Science.gov (United States)

    Marrale, Maurizio; Longo, Anna; Russo, Giorgio; Casarino, Carlo; Candiano, Giuliana; Gallo, Salvatore; Carlino, Antonio; Brai, Maria

    2015-09-01

    In this work a comparison between the response of alanine and Markus ionization chamber was carried out for measurements of the output factors (OF) of electron beams produced by a linear accelerator used for Intra-Operative Radiation Therapy (IORT). Output factors (OF) for conventional high-energy electron beams are normally measured using ionization chamber according to international dosimetry protocols. However, the electron beams used in IORT have characteristics of dose per pulse, energy spectrum and angular distribution quite different from beams usually used in external radiotherapy, so the direct application of international dosimetry protocols may introduce additional uncertainties in dosimetric determinations. The high dose per pulse could lead to an inaccuracy in dose measurements with ionization chamber, due to overestimation of ks recombination factor. Furthermore, the electron fields obtained with IORT-dedicated applicators have a wider energy spectrum and a wider angular distribution than the conventional fields, due to the presence of electrons scattered by the applicator's wall. For this reason, a dosimetry system should be characterized by a minimum dependence from the beam energy and from angle of incidence of electrons. This become particularly critical for small and bevelled applicators. All of these reasons lead to investigate the use of detectors different from the ionization chamber for measuring the OFs. Furthermore, the complete characterization of the radiation field could be accomplished also by the use of Monte Carlo simulations which allows to obtain detailed information on dose distributions. In this work we compare the output factors obtained by means of alanine dosimeters and Markus ionization chamber. The comparison is completed by the Monte Carlo calculations of OFs determined through the use of the Geant4 application "iort _ therapy" . The results are characterized by a good agreement of response of alanine pellets and Markus

  9. Single-crystal EPR and DFT studies of a [BO4]0 center in datolite: electronic structure, formation mechanism and implications

    Science.gov (United States)

    Li, Rong; Li, Zucheng; Mao, Mao; Pan, Yuanming

    2011-01-01

    A natural datolite CaBSiO4(OH) (Bergen Hill, NJ, USA), before and after gamma-ray irradiation (up to ~70 kGy), has been investigated by single-crystal and powder electron paramagnetic resonance (EPR) spectroscopy from 10 to 295 K. EPR spectra of gamma-ray-irradiated datolite show the presence of a boron-associated oxygen hole center (BOHC) and an atomic hydrogen center (H0), both of which grow with increasing radiation dose. The principal g and A(11B) values of the BOHC at 10 K are: g 1 = 2.04817(3), g 2 = 2.01179(2), g 3 = 2.00310(2), A 1 = -0.401(7) mT, A 2 = -0.906(2) mT, A 3 = -0.985(2) mT, with the orientations of the g 1 and A 1 axes approximately along the B-OH bond direction. These experimental results suggest that the BOHC represents hole trapping on the hydroxyl oxygen atom after the removal of the proton (i.e. a [BO4]0 center): via a reaction O3BOH → O3BO· + H0, where · denotes the unpaired electron. Density functional theory (DFT) calculations (CRYSTAL06, B3PW, all-electron basis sets, and 1 × 2 × 2 supercell) support the proposed structural model and yield the following 11B hyperfine coupling constants: A 1 = -0.429 mT, A 2 = -0.901 mT, A 3 = -0.954 mT, in excellent agreement with the experimental results. The [BO4]0 center undergoes the onset of thermal decay at ~200°C and is completely annealed out at 375°C but can be restored readily by gamma-ray irradiation. Isothermal annealing experiments show that the [BO4]0 center exhibits a second-order thermal decay with an activation energy of 0.96 eV. The confirmation of the [BO4]0 center (and its formation from the O3BOH precursor) in datolite has implications for not only understanding of BOHCs in alkali borosilicate glasses but also their applications to nuclear waste disposal.

  10. Broadband Transmission EPR Spectroscopy

    NARCIS (Netherlands)

    Hagen, W.R.

    2013-01-01

    EPR spectroscopy employs a resonator operating at a single microwave frequency and phase-sensitive detection using modulation of the magnetic field. The X-band spectrometer is the general standard with a frequency in the 9–10 GHz range. Most (bio)molecular EPR spectra are determined by a combination

  11. Computational dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Siebert, B.R.L.; Thomas, R.H.

    1996-01-01

    The paper presents a definition of the term ``Computational Dosimetry`` that is interpreted as the sub-discipline of computational physics which is devoted to radiation metrology. It is shown that computational dosimetry is more than a mere collection of computational methods. Computational simulations directed at basic understanding and modelling are important tools provided by computational dosimetry, while another very important application is the support that it can give to the design, optimization and analysis of experiments. However, the primary task of computational dosimetry is to reduce the variance in the determination of absorbed dose (and its related quantities), for example in the disciplines of radiological protection and radiation therapy. In this paper emphasis is given to the discussion of potential pitfalls in the applications of computational dosimetry and recommendations are given for their avoidance. The need for comparison of calculated and experimental data whenever possible is strongly stressed.

  12. Taking into account absorbed doses in tooth enamel due to internal irradiation of human body by radioactive cesium isotopes at analysis EPR dosimetry data: Calculation by Monte-Carlo method

    Energy Technology Data Exchange (ETDEWEB)

    Borysheva, N. [Medical Radiological Research Center, Korolyov str., 4, Obninsk 249020 (Russian Federation); Ivannikov, A. [Medical Radiological Research Center, Korolyov str., 4, Obninsk 249020 (Russian Federation)], E-mail: Ivannikov-Alexander@yandex.ru; Tikunov, D.; Orlenko, S.; Skvortsov, V.; Stepanenko, V. [Medical Radiological Research Center, Korolyov str., 4, Obninsk 249020 (Russian Federation); Hoshi, M. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553 (Japan)

    2007-07-15

    By Monte-Carlo simulation of ionizing particles transport, for a realistic mathematical phantom of a man supplemented by a dental region, absorbed doses in teeth enamel and whole body doses are calculated for cases of internal irradiation by {sup 137}Cs and {sup 134}Cs isotopes incorporated in the human body resulted from staying in radioactive contaminated territory. It is shown that dose in enamel constitutes (40{+-}4)% and (59{+-}6)% of whole body dose resulted from the decay of {sup 137}Cs and {sup 134}Cs isotopes, respectively. The results of calculations may be used for conversion of absorbed dose in enamel obtained by the tooth enamel EPR spectroscopy method to whole body dose for dosimetric investigation of population of territories contaminated by the radioactive cesium, which is specific for the Chernobyl accident.

  13. Properties of the silica layer during the formation of MCM-41 studied by EPR of a silica-bound spin probe.

    Science.gov (United States)

    Baute, Debbie; Frydman, Veronica; Zimmermann, Herbert; Kababya, Shifi; Goldfarb, Daniella

    2005-04-28

    The properties of the silica layer during the formation of the mesoporous material MCM-41 were investigated by electron paramagnetic resonance (EPR) experiments carried out on a specifically designed, organo(trialkoxy)silane spin probe, SL1SiEt. Minute amounts of the spin probe were co-condensed with the silica source, tetraethyl orthosilicate (TEOS), in the synthesis of MCM-41 with cetyltrimethylammonium bromide (CTAB) under basic conditions. The mobility and location of the spin probe were followed in the CTAB micellar solution before the reaction, in the reaction mixture and in the final ordered material. It was found that the EPR spectra of hydrolyzed SL1SiEt throughout the room temperature part of the reaction are characteristic of a fast tumbling species, indicating that the silica is highly fluid prior to drying. After filtering, a slow motion type spectrum was observed, showing that the spin-label experiences considerable motional hindrance. The liquidlike behavior could be restored upon stirring the material in water. When the reaction is performed with a hydrothermal stage, the spectrum of SL1SiEt in the final product is the same as that of the room temperature synthesized material, but the addition of water did not restore the high mobility, due to a higher degree of silica cross-linking. The location of SL1SiEt throughout the formation process was obtained from electron spin-echo envelope modulation (ESEEM) measurements on MCM-41 prepared with CTAB deuterated either at the N-methyl or the alpha position and in a reaction carried out in D2O. Comparing the deuterium modulation depth, k(2H), induced by CTAB-alpha-d2, CTAB-d9, or D2O in CTAB micellar solutions of a number of reference spin probes with those of SL1SiEt revealed that the hydrolyzed SL1SiEt is located near the polar heads of the surfactant in the absence of base and TEOS. This supports the postulation of charge matching at the interface as a driving force for the formation of the mesostructure

  14. Dosimetry methods

    DEFF Research Database (Denmark)

    McLaughlin, W.L.; Miller, A.; Kovacs, A.;

    2003-01-01

    Chemical and physical radiation dosimetry methods, used for the measurement of absorbed dose mainly during the practical use of ionizing radiation, are discussed with respect to their characteristics and fields of application.......Chemical and physical radiation dosimetry methods, used for the measurement of absorbed dose mainly during the practical use of ionizing radiation, are discussed with respect to their characteristics and fields of application....

  15. Dosimetry Service

    CERN Multimedia

    Dosimetry Service

    2005-01-01

    Please remember to read your dosimeter at least once every month. A regular read-out is indispensable to ensure periodic monitoring of your personal dose. You must read your dosimeter even if you have not visited the controlled areas. Film badges are no longer valid at CERN and holders of film badges are no longer allowed to enter the controlled radiation areas or work with a source. Dosimetry Service Tel. 72155 http://cern.ch/rp-dosimetry

  16. Epid Dosimetry

    Science.gov (United States)

    Greer, Peter B.; Vial, Philip

    2011-05-01

    Electronic portal imaging devices (EPIDs) were introduced originally for patient position verification. The idea of using EPIDs for dosimetry was realised in the 1980s. Little was published on the topic until the mid 1990's, when the interest in EPIDs for dosimetry increased rapidly and continues to grow. The increasing research on EPID dosimetry coincided with the introduction of intensity modulated radiation therapy (IMRT). EPIDs are well suited to IMRT dosimetry because they are high resolution, two-dimensional (2D) digital detectors. They are also pre-existing on almost all modern linear accelerators. They generally show a linear response to increasing dose. Different types of EPIDs have been clinically implemented, and these have been described in several review papers. The current generation of commercially available EPIDs are indirect detection active matrix flat panel imagers, also known as amorphous silicon (a-Si) EPIDs. Disadvantages of a-Si EPIDs for dosimetry include non-water equivalent construction materials, and the energy sensitivity and optical scatter of the phosphor scintillators used to create optical signal from the megavoltage beam. This report discusses current knowledge regarding a-Si EPIDs for dosimetry.

  17. Biomolecular EPR spectroscopy

    CERN Document Server

    Hagen, Wilfred Raymond

    2008-01-01

    Comprehensive, Up-to-Date Coverage of Spectroscopy Theory and its Applications to Biological SystemsAlthough a multitude of books have been published about spectroscopy, most of them only occasionally refer to biological systems and the specific problems of biomolecular EPR (bioEPR). Biomolecular EPR Spectroscopy provides a practical introduction to bioEPR and demonstrates how this remarkable tool allows researchers to delve into the structural, functional, and analytical analysis of paramagnetic molecules found in the biochemistry of all species on the planet. A Must-Have Reference in an Intrinsically Multidisciplinary FieldThis authoritative reference seamlessly covers all important bioEPR applications, including low-spin and high-spin metalloproteins, spin traps and spin lables, interaction between active sites, and redox systems. It is loaded with practical tricks as well as do's and don'ts that are based on the author's 30 years of experience in the field. The book also comes with an unprecedented set of...

  18. EPR spin trapping of protein radicals

    DEFF Research Database (Denmark)

    Davies, Michael Jonathan; Hawkins, Clare Louise

    2004-01-01

    Electron paramagnetic resonance (EPR) spin trapping was originally developed to aid the detection of low-molecular-mass radicals formed in chemical systems. It has subsequently found widespread use in biology and medicine for the direct detection of radical species formed during oxidative stress ...... examples of radical formation on proteins....

  19. ESR dosimetry: achievements and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Baffa, O., E-mail: baffa@usp.br [Universidade de Sao Paulo, Departamento de Fisica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil)

    2015-10-15

    Full text: Electron Spin Resonance (ESR), also known as Electron Paramagnetic Resonance (EPR) and more recently as Electron Magnetic Resonance (Emr), is a spectroscopy technique able to detect unpaired electrons such as those created by the interaction ionizing radiation with matter. When the unpaired electrons created by ionizing radiation are stable over some reasonable time, ESR can be used to measure the radiation dose deposited in the material under study. In principle, any insulating material that satisfies this requisite can be used as a dosimeter. ESR has been used in retrospective dosimetry in case of radiological accidents using natural constituents of human body such as teeth, bones and nails as well as fortuitous materials as sugar, sweeteners and plastics. When using teeth the typical detected dose is 0.5 Gy for, for X-Band spectrometers (9 GHz) and even lower doses if higher frequency spectrometers are used. Clinical dosimetry is another area of potential use of this dosimetric modality. In this application the amino acid alanine has been proposed and being used. Alanine dosimeters are very easy to prepare and require no complicated treatments for use. Alanine/ESR dosimetry satisfies many of the required properties for clinical applications such as water equivalent composition, independence of response for the energy range used in therapy and high precision. Other organic materials such as ammonium tartrate are being investigated to increase the sensitivity of ESR for clinical applications. Finally, industrial applications can also benefit from this dosimetry. The challenges to expand applications, the number of users and research groups of ESR dosimetry will be discussed. (Author)

  20. (Biological dosimetry)

    Energy Technology Data Exchange (ETDEWEB)

    Preston, R.J.

    1990-12-17

    The traveler attended the 1st International Conference on Biological Dosimetry in Madrid, Spain. This conference was organized to provide information to a general audience of biologists, physicists, radiotherapists, industrial hygiene personnel and individuals from related fields on the current ability of cytogenetic analysis to provide estimates of radiation dose in cases of occupational or environmental exposure. There is a growing interest in Spain in biological dosimetry because of the increased use of radiation sources for medical and occupational uses, and with this the anticipated and actual increase in numbers of overexposure. The traveler delivered the introductory lecture on Biological Dosimetry: Mechanistic Concepts'' that was intended to provide a framework by which the more applied lectures could be interpreted in a mechanistic way. A second component of the trip was to provide advice with regard to several recent cases of overexposure that had been or were being assessed by the Radiopathology and Radiotherapy Department of the Hospital General Gregorio Maranon'' in Madrid. The traveler had provided information on several of these, and had analyzed cells from some exposed or purportedly exposed individuals. The members of the biological dosimetry group were referred to individuals at REACTS at Oak Ridge Associated Universities for advice on follow-up treatment.

  1. THERMOLUMINESCENT DOSIMETRY

    African Journals Online (AJOL)

    2005-10-20

    Oct 20, 2005 ... abo area of the city has the least radiation dose rate while Obantoku area has the upper limit. aking this as ... 'n Abeokuta. eywords: Environmental radiation, thermoluminescent dosimetry, Abeokuta, outdoor ... Both 238U and 232Th have long decay series with ... effects of radiation exposure (Hanson and.

  2. THERMOLUMINESCENT DOSIMETRY

    African Journals Online (AJOL)

    2005-10-20

    Oct 20, 2005 ... abo area of the city has the least radiation dose rate while Obantoku area has the upper limit. aking this as ... “n Abeokuta. eywords: Environmental radiation, thermoluminescent dosimetry, Abeokuta, outdoor ... Both 238U and 232Th have long decay series with ... effects of radiation exposure (Hanson and.

  3. EPR measurements of fingernails in Q-band

    Energy Technology Data Exchange (ETDEWEB)

    Romanyukha, Alex, E-mail: Alexander.Romanyukha@med.navy.mil [Naval Dosimetry Center, Bethesda, MD (United States); Trompier, Francois [Institut de Radioprotection et de Surete Nucleaire, Fontenay-aux-Roses Cedex (France); Reyes, Ricardo A. [Uniformed Services University of the Health Sciences, Bethesda, MD (United States); Melanson, Mark A. [Armed Forces Radiobiology Research Institute, Bethesda, MD (United States)

    2011-09-15

    Results of a feasibility study for the use of the Q-band EPR measurements of fingernails are presented. Details of the first protocol developed for Q-band (34 GHz) EPR dose measurements in fingernails and preliminary results of a dosimetry study in comparison with the commonly-used X-band (9 GHz) are reported. It was found that 1-5 mg sample mass was sufficient for EPR measurements in fingernails in the Q-band, which is significantly less than the 15-30 mg needed for the X-band. This finding makes it possible to obtain sufficient fingernail sample for dose measurements, practically from every finger of any person. Another finding was that the spectral resolution of the mechanically-induced signal (MIS) and radiation-induced signal (RIS) in the Q-band was significantly better than in the X-band. The RIS and MIS in the Q-band spectrum have a more complex structure than in the X-band, which potentially offers the possibility to do dose measurements in fingernails without treatment and immediately after clipping. These findings and recent results related to fingernail dosimetry in the Q-band and its perspectives are discussed here.

  4. Dosimetry Service

    CERN Multimedia

    Dosimetry Service

    2005-01-01

    Please remember to read your dosimeter every month at least once and preferably during the first week. A regular read-out is indispensable in order to ensure a periodic monitoring of the personal dose. You should read your dosimeter even if you have not visited the controlled areas. If you still have the old dosimeter (film badge), please send it immediately for evaluation to us (Bdg 24 E-011). After January 2005 there will be no developing process for the old film system. Information for Contractors: Please remember also to bring the form ‘Confirm Reception of a CERN Dosimeter' signed with ‘Feuille d'enregistrement du CERN'. Without these forms the dosimeter cannot be assigned. Thank you for your cooperation. Dosimetry Service Tel 767 2155 http://cern.ch/rp-dosimetry

  5. Radiation dosimetry.

    OpenAIRE

    Cameron, J

    1991-01-01

    This article summarizes the basic facts about the measurement of ionizing radiation, usually referred to as radiation dosimetry. The article defines the common radiation quantities and units; gives typical levels of natural radiation and medical exposures; and describes the most important biological effects of radiation and the methods used to measure radiation. Finally, a proposal is made for a new radiation risk unit to make radiation risks more understandable to nonspecialists.

  6. Use of electron paramagnetic resonance dosimetry with tooth enamel for retrospective dose assessment. Report of a co-ordinated research project

    CERN Document Server

    2002-01-01

    Electron paramagnetic resonance (EPR) dosimetry is a physical method for the assessment of absorbed dose from ionising radiation. It is based on the measurement of stable radiation induced radicals in human calcified tissues (primarily in tooth enamel). EPR dosimetry with teeth is now firmly established in retrospective dosimetry. It is a powerful method for providing information on exposure to ionising radiation many years after the event, since the 'signal' is 'stored' in the tooth or the bone. This technique is of particular relevance to relatively low dose exposures or when the results of conventional dosimetry are not available (e.g. in accidental circumstances). The use of EPR dosimetry, as an essential tool for retrospective assessment of radiation exposure is an important part of radioepidemiological studies and also provides data to select appropriate countermeasures based on retrospective evaluation of individual doses. Despite well established regulations and protocols for maintaining radiation pro...

  7. Broadband transmission EPR spectroscopy.

    Directory of Open Access Journals (Sweden)

    Wilfred R Hagen

    Full Text Available EPR spectroscopy employs a resonator operating at a single microwave frequency and phase-sensitive detection using modulation of the magnetic field. The X-band spectrometer is the general standard with a frequency in the 9-10 GHz range. Most (biomolecular EPR spectra are determined by a combination of the frequency-dependent electronic Zeeman interaction and a number of frequency-independent interactions, notably, electron spin - nuclear spin interactions and electron spin - electron spin interactions, and unambiguous analysis requires data collection at different frequencies. Extant and long-standing practice is to use a different spectrometer for each frequency. We explore the alternative of replacing the narrow-band source plus single-mode resonator with a continuously tunable microwave source plus a non-resonant coaxial transmission cell in an unmodulated external field. Our source is an arbitrary wave digital signal generator producing an amplitude-modulated sinusoidal microwave in combination with a broadband amplifier for 0.8-2.7 GHz. Theory is developed for coaxial transmission with EPR detection as a function of cell dimensions and materials. We explore examples of a doublet system, a high-spin system, and an integer-spin system. Long, straigth, helical, and helico-toroidal cells are developed and tested with dilute aqueous solutions of spin label hydroxy-tempo. A detection limit of circa 5 µM HO-tempo in water at 800 MHz is obtained for the present setup, and possibilities for future improvement are discussed.

  8. Topics in radiation dosimetry radiation dosimetry

    CERN Document Server

    1972-01-01

    Radiation Dosimetry, Supplement 1: Topics in Radiation Dosimetry covers instruments and techniques in dealing with special dosimetry problems. The book discusses thermoluminescence dosimetry in archeological dating; dosimetric applications of track etching; vacuum chambers of radiation measurement. The text also describes wall-less detectors in microdosimetry; dosimetry of low-energy X-rays; and the theory and general applicability of the gamma-ray theory of track effects to various systems. Dose equivalent determinations in neutron fields by means of moderator techniques; as well as developm

  9. Quantitative EPR A Practitioners Guide

    CERN Document Server

    Eaton, Gareth R; Barr, David P; Weber, Ralph T

    2010-01-01

    This is the first comprehensive yet practical guide for people who perform quantitative EPR measurements. No existing book provides this level of practical guidance to ensure the successful use of EPR. There is a growing need in both industrial and academic research to provide meaningful and accurate quantitative EPR results. This text discusses the various sample, instrument and software related aspects required for EPR quantitation. Specific topics include: choosing a reference standard, resonator considerations (Q, B1, Bm), power saturation characteristics, sample positioning, and finally, putting all the factors together to obtain an accurate spin concentration of a sample.

  10. Dosimetry of the mixed field irradiation facility CALIBAN

    Energy Technology Data Exchange (ETDEWEB)

    Trompier, F. [Institute for Radiological Protection and Nuclear Safety, 92265 Fontenay-aux-roses (France)], E-mail: francois.trompier@irsn.fr; Huet, C.; Medioni, R.; Robbes, I. [Institute for Radiological Protection and Nuclear Safety, 92265 Fontenay-aux-roses (France); Asselineau, B. [Institute of Radioprotection and Nuclear Safety, 13115 St Paul-Lez-Durance (France)

    2008-02-15

    The dosimetry of the experimental reactor CALIBAN was established for photon and neutron components, and the kerma variations were evaluated according to position (distance from the core, height, angle with the median room axis). Dosimetry was performed with TLD (Al{sub 2}O{sub 3}) for the photon component, and with passive silicon diodes, activation detectors (Au, In, Ni, Mg, Cu) and alanine pellets measured by EPR spectrometry for the neutron component. The neutron energy distribution was experimentally evaluated at various distances based on the activities measured at the activated foil using the SNAC2 software. It was then compared with those calculated with the Monte Carlo code MCNPX.

  11. A fast method for ionized food identification: EPR. Une methode rapide d'identification des aliments ionises: la RPE

    Energy Technology Data Exchange (ETDEWEB)

    Raffi, J. (CEA Centre d' Etudes Nucleaires de Cadarache, 13 - Saint-Paul-lez-Durance (FR)); Rubel, G. (Bruker spectrospin, 67 - Wissembourg (FR))

    1990-12-01

    Electronic paramagnetic resonance allows the detection of ionized food only after dry storage, avoiding reaction of radicals with water. Dry and solid parts are used for analysis (bones for meat and fish, kernels for fruits). Dosimetry is possible by EPR spectrometry of alanine-L fixed on products treated in industrial irradiators.

  12. In Vivo Imaging of Tissue Physiological Function using EPR Spectroscopy | NCI Technology Transfer Center | TTC

    Science.gov (United States)

    Electron paramagnetic resonance (EPR) is a technique for studying chemical species that have one or more unpaired electrons.  The current invention describes Echo-based Single Point Imaging (ESPI), a novel EPR image formation strategy that allows in vivo imaging of physiological function.  The National Cancer Institute's Radiation Biology Branch is seeking statements of capability or interest from parties interested in in-licensing an in vivo imaging using Electron paramagnetic resonance (EPR) to measure active oxygen species.

  13. Dosimetry for radiation processing

    DEFF Research Database (Denmark)

    Miller, Arne

    1986-01-01

    During the past few years significant advances have taken place in the different areas of dosimetry for radiation processing, mainly stimulated by the increased interest in radiation for food preservation, plastic processing and sterilization of medical products. Reference services both...... and sterilization dosimetry, optichromic dosimeters in the shape of small tubes for food processing, and ESR spectroscopy of alanine for reference dosimetry. In this paper the special features of radiation processing dosimetry are discussed, several commonly used dosimeters are reviewed, and factors leading...

  14. Retrospective accident dosimetry using trapped charges

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

    Dicentric chromosome aberrations technique scoring of aberrations in metaphases prepared from human lymphocytes is most commonly used. This is considered as a reliable technique because the sample is extracted from the individual human body itself. There are other techniques in biological dosimetry such as Fluorescence In Situ Hybridization (FISH) using translocations, premature chromosome condensation (PCC) and micronucleus assay. However the minimum detectable doses (MDD) are relatively high and sample preparation time is also relatively longer. Therefore, there is limitation in use of these techniques for the purpose of triage in a short time in case of emergency situation relating large number of persons. Electronic paramagnetic resonance (EPR) technique is based on the signal from unpaired electrons such as free radicals in irradiated materials especially tooth enamel, however it has also limitation for the purpose of triage because of difficulty of sample taking and its high MDD. Recently as physical methods, thermoluminescence (TL) and optically stimulated luminescence (OSL) technique have been attracted due to its lower MDD and simplicity of sample preparation. Density of the trapped charges is generally proportional to the radiation dose absorbed and the intensity of emitting light is also proportional to the density of trapped charges, thus it can be applied to measure radiation dose retrospectively. In this presentation, TL and OSL techniques are going to introduced and discussed as physical methods for retrospective accident dosimetry using trapped charges especially in electronic component materials. As a tool for dose reconstruction for emergency situation, thermoluminescece and optically stimulated luminescence techniques which are based on trapped charges during exposure of material are introduced. These techniques have several advantages such as high sensitivity, fast evaluation and ease to sample collection over common biological dosimetry and EPR

  15. Formation and characterization of ultrafine nanophosphors of lithium tetraborate (Li2B4O7 for personnel and medical dosimetry

    Directory of Open Access Journals (Sweden)

    Nasrin Khalilzadeh

    2016-07-01

    Full Text Available The present study demonstrates an innovative single-step thermal synthesis of nano-sized lithium tetraborate dosimeter and its characterization. The optimum calcination temperature and time for the synthesis of the nanoparticles material was 750 °C and 2 h, respectively. Characterization of the samples was carried out using X-ray diffractometry (XRD, Fourier transform infrared (FT-IR spectroscopy, transmission electron microscopy (TEM, and thermoluminescence (TL. FT-IR, XRD and TEM results confirmed the formation of pure nano-crystalline lithium tetraborate. The product showed a linear response over a wide range of doses from 10−1 to 1.5 × 102 Gy. Moreover, the samples illustrate non-energy dependence among a wide range energy interval from 24 keV up to 1250 keV and almost no fading during one month storage.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-15

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

  17. Harmonization of dosimetric information obtained by different EPR methods: Experience of the Techa river study

    Energy Technology Data Exchange (ETDEWEB)

    Volchkova, A. [Urals Research Center for Radiation Medicine, 68A, Vorovsky Str., 454076 Chelyabinsk (Russian Federation); Shishkina, E.A., E-mail: ElenaA.Shishkina@gmail.com [Urals Research Center for Radiation Medicine, 68A, Vorovsky Str., 454076 Chelyabinsk (Russian Federation); Ivanov, D. [Institute of Metal Physics, Russian Academy of Sciences, 18, S. Kovalevskoy Str., 620041 Yekaterinburg (Russian Federation); Timofeev, Yu. [Urals Research Center for Radiation Medicine, 68A, Vorovsky Str., 454076 Chelyabinsk (Russian Federation); Fattibene, P.; Della Monaca, S. [Istituto Superiore di Sanita and Istituto Nazionale di Fisica Nucleare, Viale Regina Elena 299, 00161 Rome (Italy); Wieser, A. [Helmholtz Zentrum Muenchen, German Research Centre for Environmental Health, D-85764 Neuherberg (Germany); Degteva, M.O. [Urals Research Center for Radiation Medicine, 68A, Vorovsky Str., 454076 Chelyabinsk (Russian Federation)

    2011-09-15

    Between 1949 and 1956 the Techa River (Southern Urals, Russia) was contaminated as a result of releases of radioactive waste by the Mayak Production Association. EPR dosimetry with tooth enamel has been used to estimate the external exposure of Techa riverside residents over the last 17 years. The database 'Tooth' of the Urals Research Center for Radiation Medicine (URCRM) has accumulated about 1000 EPR measurements of tooth enamel from the rural population of the Urals region. The teeth were investigated by laboratories of Russia, USA, Germany and Italy. Most of the enamel samples were measured several times in different laboratories. Each laboratory used different equipment and its own methods for sample preparation and EPR spectra analysis. Even measurements performed at the same laboratory over 10-15 years may not be assumed as uniform: methods change with time, and equipment is subject to aging. These two factors influenced EPR performance. The purpose of this study is, therefore, the harmonization of EPR data accumulated during long-term dosimetric investigations in the Southern Urals for further pooled analysis. The results will be used for external dose evaluation in the Techa River region.

  18. EPR: the nuclear impasse; EPR: l'impasse nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Marillier, F. [Association Ecologiste Greenpeace (France)

    2008-07-01

    The questions relative to the climatic change constitute crucial challenges for the next ten years. In this context the author aims to show how the EPR project illustrates the nuclear french ''autism''. He presents and analyzes the international and environmental impacts of this obsolete technology, as a project useless and dangerous. (A.L.B.)

  19. Dosimetry service removal

    CERN Multimedia

    Safety Commission

    2010-01-01

    Dear personal dosimeter user, Please note that the Dosimetry service has moved in building 55, the service is now located in the main floor: 55-R-004. Main floor instead of second floor. On your right hand when accessing in the building. Thank you Dosimetry Service

  20. The Flamanville 3 EPR reactor; Le reacteur EPR Flamanville 3

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    On April 10. 2007, the french government authorized EDF to create on the site of Flamanville ( La Manche) a nuclear base installation containing a pressurized water EPR type reactor. This nuclear reactor, conceived by AREVA NP and EDF, is the first copy of a generation susceptible to replace later, at least partly, the French nuclear reactors at present in operation.Within the framework of its mission of technical support of the Authority of Nuclear Safety ( A.S.N.), the I.R.S.N. widely contributed successively: to define the general objectives of safety assigned to this new generation of pressurized water nuclear reactors; to analyze the options of safety proposed by EDF for the EPR project; To deepen, upstream to the authorization of creation, the evaluation of the step of safety and the measures of conception retained by EDF that have to allow to respect the objectives of safety which were notified to it. (N.C.)

  1. Preliminary study on electron paramagnetic resonance (EPR) signal properties of mobile phone components for dose estimation in radiation accident

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byeong Ryong; Ha, Wi Ho; Park, Sun Hoo; Lee, Jin Kyeong; Lee, Seung Sook [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2015-12-15

    We have investigated the EPR signal properties in 12 components of two mobile phones (LCD, OLED) using electron paramagnetic resonance (EPR) spectrometer in this study.EPR measurements were performed at normal atmospheric conditions using Bruker EXEXSYS-II E500 spectrometer with X-band bridge, and samples were irradiated by {sup 137}C{sub s} gamma-ray source. To identify the presence of radiation-induced signal (RIS), the EPR spectra of each sample were measured unirradiated and irradiated at 50 Gy. Then, dose-response curve and signal intensity variating by time after irradiation were measured. As a result, the signal intensity increased after irradiation in all samples except the USIM plastic and IC chip. Among the samples, cover glass(CG), lens, light guide plate(LGP) and diffusion sheet have shown fine linearity (R{sup 2} > 0.99). Especially, the LGP had ideal characteristics for dosimetry because there were no signal in 0 Gy and high rate of increase in RIS. However, this sample showed weakness in fading. Signal intensity of LGP and Diffusion Sheet decreased by 50% within 72 hours after irradiation, while signals of Cover Glass and Lens were stably preserved during the short period of time. In order to apply rapidly EPR dosimetry using mobile phone components in large-scale radiation accidents, further studies on signal differences for same components of the different mobile phone, fading, pretreatment of samples and processing of background signal are needed. However, it will be possible to do dosimetry by dose-additive method or comparative method using unirradiated same product in small-scale accident.

  2. Egyptian limestone for gamma dosimetry: an electron paramagnetic resonance study

    Science.gov (United States)

    Salama, E.

    2014-04-01

    The electron paramagnetic resonance (EPR) properties of limestone from a certain Egyptian site were investigated in order to propose an efficient and low-cost gamma dosimeter. Radiation-induced free radicals were of one type which was produced in the limestone samples at g=2.0066 after exposure to gamma radiation (60Co). EPR spectrum was recorded and analyzed. The microwave power saturation curve and the effect of changing modulation amplitude on peak-to- peak signal height were investigated. The response of limestone to different radiation doses (0.5-20 kGy) was studied. Except for the decrease in signal intensities during the first five hours following irradiation, over the period of two months fair stabilities of signal intensities were noticed. From the current results, it is possible to conclude that natural limestone may be a suitable material for radiation dosimetry in the range of irradiation processing.

  3. A cryogenic receiver for EPR.

    Science.gov (United States)

    Narkowicz, R; Ogata, H; Reijerse, E; Suter, D

    2013-12-01

    Cryogenic probes have significantly increased the sensitivity of NMR. Here, we present a compact EPR receiver design capable of cryogenic operation. Compared to room temperature operation, it reduces the noise by a factor of ≈2.5. We discuss in detail the design and analyze the resulting noise performance. At low microwave power, the input noise density closely follows the emission of a cooled 50Ω resistor over the whole measurement range from 20K up to room temperature. To minimize the influence of the microwave source noise, we use high microwave efficiency (≈1.1-1.7mTW(-1/2)) planar microresonators. Their efficient conversion of microwave power to magnetic field permits EPR measurements with very low power levels, typically ranging from a few μW down to fractions of nW. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Hydrogen Analyses in the EPR

    Energy Technology Data Exchange (ETDEWEB)

    Worapittayaporn, S.; Eyink, J.; Movahed, M. [AREVA NP GmbH, P.O. Box 3220, D-91050 Erlangen (Germany)

    2008-07-01

    In severe accidents with core melting large amounts of hydrogen may be released into the containment. The EPR provides a combustible gas control system to prevent hydrogen combustion modes with the potential to challenge the containment integrity due to excessive pressure and temperature loads. This paper outlines the approach for the verification of the effectiveness and efficiency of this system. Specifically, the justification is a multi-step approach. It involves the deployment of integral codes, lumped parameter containment codes and CFD codes and the use of the sigma criterion, which provides the link to the broad experimental data base for flame acceleration (FA) and deflagration to detonation transition (DDT). The procedure is illustrated with an example. The performed analyses show that hydrogen combustion at any time does not lead to pressure or temperature loads that threaten the containment integrity of the EPR. (authors)

  5. Dosimetry using environmental and biological materials. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Haskell, E.; Kenner, G.; Hayes, R.

    1998-02-01

    This report summarizes a five year effort to improve the sensitivity and reliability of retrospective dosimetry methods, to collaborate with laboratories engaged in related research and to share the technology with startup laboratories seeking similar capabilities. This research program has focused on validation of electron paramagnetic resonance (EPR) as a dosimetry tool and on optimization of the technique by reducing the lower limits of detection, simplifying the process of sample preparation and analysis and speeding analysis to allow greater throughput in routine measurement situations. The authors have investigated the dosimetric signal of hard tissues in enamel, deorganified dentin, synthetic carbonated apatites and synthetic hydroxyapatite. This research has resulted in a total of 27 manuscripts which have been published, are in press, or have been submitted for publication. Of these manuscripts, 14 are included in this report and were indexed separately for inclusion in the data base.

  6. EPR of exchange coupled systems

    CERN Document Server

    Bencini, Alessandro

    2012-01-01

    From chemistry to solid state physics to biology, the applications of Electron Paramagnetic Resonance (EPR) are relevant to many areas. This unified treatment is based on the spin Hamiltonian approach and makes extensive use of irreducible tensor techniques to analyze systems in which two or more spins are magnetically coupled. This edition contains a new Introduction by coauthor Dante Gatteschi, a pioneer and scholar of molecular magnetism.The first two chapters review the foundations of exchange interactions, followed by examinations of the spectra of pairs and clusters, relaxation in oligon

  7. USE OF-EPR-DL FIELD TEST EQUIPMENT FOR DETECTION OF SIGMA PHASE

    Directory of Open Access Journals (Sweden)

    Abraão Danilo Gomes Barreto

    2014-06-01

    Full Text Available This work has objective to correlate the intergranular corrosion susceptibility test named EPR-DL (Electrochemical Potentiokinetic Reactivation of Double Loop with the sigma phase formation and other phases. It has been used samples from a UNS S32760 steel pipe for conducting various aging heat treatments. Held isothermal heat treatment at 850°C for 1 min, 10 min, 30 min, 1 h, 1h30min and 10 h. Each heat treated sample and as received were tested using the electrochemical polarization reactivation of double loop technique (EPR-DL. It was possible the detection of deleterious phases with DL-EPR portable cell. The EPR-DL test of some samples showed a second peak of reactivation in which the results showed that this peak might be associated with ferrite or be related to the presence of chi phase

  8. Overview of LBB implementation for the EPR

    Energy Technology Data Exchange (ETDEWEB)

    Cauquelin, C.

    1997-04-01

    This paper presents an overview of the use of leak-before-break (LBB) analysis for EPR reactors. EPR is an evolutionary Nuclear Island of the 4 loop x 1500 Mwe class currently in the design phase. Application of LBB to the main coolant lines and resulting design impacts are summarized. Background information on LBB analysis in France and Germany is also presented.

  9. INDIVIDUAL DOSIMETRY SERVICE

    CERN Multimedia

    2000-01-01

    Personnel in the distribution groups Aleph, Delphi, L3, Opal who also work for other experiments than at LEP, should contact their dispatchers to explain their activities for the future, after LEP dismantling in order to be maintained on the regular distribution list at Individual DosimetryWe inform all staff and users under regular dosimetric control that the dosimeters for the monitoring period MAY/JUNE will be available from their usual dispatchers on Tuesday 2 May.Please have your films changed before the 12 May.The colour of the dosimeter valid in is MAY/JUNE is YELLOW.Individual Dosimetry Service will be closed on Friday 28 April.

  10. Nuclear medicine radiation dosimetry

    CERN Document Server

    McParland, Brian J

    2010-01-01

    Complexities of the requirements for accurate radiation dosimetry evaluation in both diagnostic and therapeutic nuclear medicine (including PET) have grown over the past decade. This is due primarily to four factors: growing consideration of accurate patient-specific treatment planning for radionuclide therapy as a means of improving the therapeutic benefit, development of more realistic anthropomorphic phantoms and their use in estimating radiation transport and dosimetry in patients, design and use of advanced Monte Carlo algorithms in calculating the above-mentioned radiation transport and

  11. Dosimetry for SIRT; Dosimetrie bei der SIRT

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, S.P. [Universitatesklinikum Essen (Germany). Klinik fuer Nuklearmedizin

    2011-09-15

    Dosimetry is only one aspect of treatment planning for 'Selective internal radiotherapy' (SIRT) or 'transarterial radioembolization' (TARE) with Yttrium-90 Microspheres is an emerging palliative therapy for malignant hepatoma. Dosimetric considerations, together with interventional, oncological and hepatological aspects need to be considered for optimal treatment stratification. The product-specific dosimetric calculations for 2 commercially available microsphere products are compared and set in relation to the average doses to liver and tumor. Ostensible discrepancies between the dose-response of Y-90-microspheres and external beam radiation therapy are discussed in the context of radiobiological concepts. (orig.)

  12. Status of radiation processing dosimetry

    DEFF Research Database (Denmark)

    Miller, A.

    1993-01-01

    Several milestones have marked the field of radiation processing dosimetry since IMRP 7. Among them are the IAEA symposium on High Dose Dosimetry for Radiation Processing and the international Workshops on Dosimetry for Radiation Processing organized by the ASTM. Several standards have been...... or are being published by the ASTM in this field, both on dosimetry procedures and on the proper use of specific dosimeter systems. Several individuals are involved in this international cooperation which contribute significantly to the broader understanding of the role of dosimetry in radiation processing....... The importance of dosimetry is emphasized in the standards on radiation sterilization which are currently drafted by the European standards organization CEN and by the international standards organization ISO. In both standards, dosimetry plays key roles in characterization of the facility, in qualification...

  13. Nitrosyl hemoglobins: EPR above 80 K

    Energy Technology Data Exchange (ETDEWEB)

    Wajnberg, E.; Bemski, G.; El-Jaick, L.J.; Alves, O.C.

    1995-03-01

    The EPR spectra of nitrosyl hemoglobin and myoglobin in different conditions (native, denatured and lyophilized), as well as of hematin-NO were obtained in the temperature range of 80 K-280 K. There is a substantial and reversible.decrease of the areas of the EPR spectra of all the hemoglobin samples above 150 K. The interpretation of the results implies the existence of two conformational states in thermal equilibrium only one of which is EPR detectable. Thermodynamical parameters are determined for the hexa and penta-coordinated cases. (author). 25 refs, 3 figs.

  14. High frequency electromagnetic dosimetry

    CERN Document Server

    Sánchez-Hernández, David A

    2009-01-01

    Along with the growth of RF and microwave technology applications, there is a mounting concern about the possible adverse effects over human health from electromagnetic radiation. Addressing this issue and putting it into perspective, this groundbreaking resource provides critical details on the latest advances in high frequency electromagnetic dosimetry.

  15. Individual dosimetry service

    CERN Document Server

    2004-01-01

    We inform all staff and users under regular dosimetry control that the dosimeters for the monitoring period JULY-AUGUST 2004 are available from their usual dispatchers. Please have your films changed before the 15 JULY 2004. The color of the dosimeter valid in July-August 2004 is PINK.

  16. Tetrachloridocuprates(II—Synthesis and Electron Paramagnetic Resonance (EPR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Peter Strauch

    2012-02-01

    Full Text Available Ionic liquids (ILs on the basis of metal containing anions and/or cations are of interest for a variety of technical applications e.g., synthesis of particles, magnetic or thermochromic materials. We present the synthesis and the results of electron paramagnetic resonance (EPR spectroscopic analyses of a series of some new potential ionic liquids based on tetrachloridocuprates(II, [CuCl4]2−, with different sterically demanding cations: hexadecyltrimethylammonium 1, tetradecyltrimethylammonium 2, tetrabutylammonium 3 and benzyltriethylammonium 4. The cations in the new compounds were used to achieve a reasonable separation of the paramagnetic Cu(II ions for EPR spectroscopy. The EPR hyperfine structure was not resolved. This is due to the exchange broadening, resulting from still incomplete separation of the paramagnetic Cu(II centers. Nevertheless, the principal values of the electron Zeemann tensor (g║ and g┴ of the complexes could be determined. Even though the solid substances show slightly different colors, the UV/Vis spectra are nearly identical, indicating structural changes of the tetrachloridocuprate moieties between solid state and solution. The complexes have a promising potential e.g., as high temperature ionic liquids, as precursors for the formation of copper chloride particles or as catalytic paramagnetic ionic liquids.

  17. The EPR in a few words: all you need to know about the EPR nuclear reactor; L'EPR en bref: ce qu'il faut savoir sur le reacteur nucleaire EPR

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    After a brief presentation of the EPR (European - or Evolutionary - Pressurized Reactor) type nuclear reactor, this paper, proposed by the collective group 'Stop EPR', develops the following points: EPR is as dangerous as other reactors; EPR flouts democracy; France's energy demand do not need the construction of EPRs; the construction of EPRs is not a factor of economical and social development; EPR should not be constructed neither in France nor elsewhere and the present building sites should be cancelled; the EPR will not help France to increase its energy independence and protect itself from oil price increases; choosing the EPR is incompatible with the large investments to be made in energy conservation and renewable energies; the EPR is not a solution to climate change; the VHV line corridor that will starts at Flamanville is not justified and poses risks to the environment and public health

  18. The dosimetry of ionizing radiation

    CERN Document Server

    1990-01-01

    A continuation of the treatise The Dosimetry of Ionizing Radiation, Volume III builds upon the foundations of Volumes I and II and the tradition of the preceeding treatise Radiation Dosimetry. Volume III contains three comprehensive chapters on the applications of radiation dosimetry in particular research and medical settings, a chapter on unique and useful detectors, and two chapters on Monte Carlo techniques and their applications.

  19. SU-C-BRD-05: Non-Invasive in Vivo Biodosimetry in Radiotherapy Patients Using Electron Paramagnetic Resonance (EPR) Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bahar, N; Roberts, K; Stabile, F; Mongillo, N; Decker, RD; Wilson, LD; Husain, Z; Contessa, J; Carlson, DJ [Yale University School of Medicine, New Haven, Connecticut (United States); Williams, BB; Flood, AB; Swartz, HM [Geisel Medical School at Dartmouth University, Hanover, New Hampshire (United States)

    2015-06-15

    Purpose: Medical intervention following a major, unplanned radiation event can elevate the human whole body exposure LD50 from 3 to 7 Gy. On a large scale, intervention cannot be achieved effectively without accurate and efficient triage. Current methods of retrospective biodosimetry are restricted in capability and applicability; published human data is limited. We aim to further develop, validate, and optimize an automated field-deployable in vivo electron paramagnetic resonance (EPR) instrument that can fill this need. Methods: Ionizing radiation creates highly-stable, carbonate-based free radicals within tooth enamel. Using a process similar to nuclear magnetic resonance, EPR directly measures the presence of radiation-induced free radicals. We performed baseline EPR measurements on one of the upper central incisors of total body irradiation (TBI) and head and neck (H&N) radiotherapy patients before their first treatment. Additional measurements were performed between subsequent fractions to examine the EPR response with increasing radiation dose. Independent dosimetry measurements were performed with optically-stimulated luminescent dosimeters (OSLDs) and diodes to more accurately establish the relationship between EPR signal and delivered radiation dose. Results: 36 EPR measurements were performed over the course of four months on two TBI and four H & N radiotherapy patients. We observe a linear increase in EPR signal with increasing dose across the entirety of the tested range. A linear least squares-weighted fit of delivered dose versus measured signal amplitude yields an adjusted R-square of 0.966. The standard error of inverse prediction (SEIP) is 1.77 Gy. For doses up to 7 Gy, the range most relevant to triage, we calculate an SEIP of 1.29 Gy. Conclusion: EPR spectroscopy provides a promising method of retrospective, non-invasive, in vivo biodosimetry. Our preliminary data show an excellent correlation between predicted signal amplitude and delivered

  20. Quantitative imaging for clinical dosimetry

    Science.gov (United States)

    Bardiès, Manuel; Flux, Glenn; Lassmann, Michael; Monsieurs, Myriam; Savolainen, Sauli; Strand, Sven-Erik

    2006-12-01

    Patient-specific dosimetry in nuclear medicine is now a legal requirement in many countries throughout the EU for targeted radionuclide therapy (TRT) applications. In order to achieve that goal, an increased level of accuracy in dosimetry procedures is needed. Current research in nuclear medicine dosimetry should not only aim at developing new methods to assess the delivered radiation absorbed dose at the patient level, but also to ensure that the proposed methods can be put into practice in a sufficient number of institutions. A unified dosimetry methodology is required for making clinical outcome comparisons possible.

  1. Neutron beam measurement dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Amaro, C.R. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1995-11-01

    This report describes animal dosimetry studies and phantom measurements. During 1994, 12 dogs were irradiated at BMRR as part of a 4 fraction dose tolerance study. The animals were first infused with BSH and irradiated daily for 4 consecutive days. BNL irradiated 2 beagles as part of their dose tolerance study using BPA fructose. In addition, a dog at WSU was irradiated at BMRR after an infusion of BPA fructose. During 1994, the INEL BNCT dosimetry team measured neutron flux and gamma dose profiles in two phantoms exposed to the epithermal neutron beam at the BMRR. These measurements were performed as a preparatory step to the commencement of human clinical trials in progress at the BMRR.

  2. INDIVIDUAL DOSIMETRY SERVICE

    CERN Multimedia

    2000-01-01

    Personnel in the distribution groups Aleph, Delphi, L3, Opal who also work for other experiments than at LEP, should contact the Individual Dosimetry Service.We inform all staff and users under regular dosimetric control that the dosimeters for the monitoring period MARCH/APRIL will be available from their usual dispatchers on the third of March 2000.Please have your films changed before the 13th of March.The colour of the dosimeter valid in MARCH/APRIL is BLUE.

  3. INDIVIDUAL DOSIMETRY SERVICE

    CERN Multimedia

    1999-01-01

    Personnel in the distribution groups Aleph, Delphi, L3, Opal who also work for other experiments than at LEP, should contact the Individual Dosimetry ServiceWe inform all staff and users under regular dosimetric control that the dosimeters for the monitoring period JANUARY/FEBRUARY will be available from their usual dispatchers on Monday the third of January 2000.Please have your films changed:before the 12 January.The colour of the dosimeter valid in JANUARY/FEBRUARY is WHITE.

  4. Dosimetry: an ARDENT topic

    CERN Multimedia

    CERN Bulletin

    2012-01-01

    The first annual ARDENT workshop took place in Vienna from 20 to 23 November. The workshop gathered together the Early-Stage Researchers (ESR) and their supervisors, plus other people involved from all the participating institutions.   “The meeting, which was organised with the local support of the Austrian Institute of Technology, was a nice opportunity for the ESRs to get together, meet each other, and present their research plans and some preliminary results of their work,” says Marco Silari, a member of CERN Radiation Protection Group and the scientist in charge of the programme. Two full days were devoted to a training course on radiation dosimetry, delivered by renowned experts. The workshop closed with a half-day visit to the MedAustron facility in Wiener Neustadt. ARDENT (Advanced Radiation Dosimetry European Network Training) is a Marie Curie ITN project funded under EU FP7 with €4 million. The project focuses on radiation dosimetry exploiting se...

  5. Nitric oxide adsorbed on zeolites: EPR studies.

    Science.gov (United States)

    Yahiro, Hidenori; Lund, Anders; Shiotani, Masaru

    2004-05-01

    CW-EPR studies of NO adsorbed on sodium ion-exchanged zeolites were focused on the geometrical structure of NO monoradical and (NO)2 biradical formed on zeolites. The EPR spectrum of NO monoradical adsorbed on zeolite can be characterized by the three different g-tensor components and the resolved y-component hyperfine coupling with the 14N nucleus. Among the g-tensor components, the value of g(zz) is very sensitive to the local environment of zeolite and becomes a measure of the electrostatic field in zeolite. The temperature dependence of the g-tensor demonstrated the presence of two states of the Na-NO adduct, in rigid and rotational states. The EPR spectra of NO adsorbed on alkaline metal ion-exchanged zeolite and their temperature dependency are essentially the same as that on sodium ion-exchanged zeolite. On the other hand, for NO adsorbed on copper ion-exchanged zeolite it is known that the magnetic interaction between NO molecule and paramagnetic copper ion are observable in the spectra recorded at low temperature. The signals assigned to (NO)2 biradical were detected for EPR spectrum of NO adsorbed on Na-LTA. CW-EPR spectra as well as their theoretical calculation suggested that the two NO molecules are aligned along their N-O bond axes. A new procedure for automatical EPR simulation is described which makes it possible to analyze EPR spectrum easily. In the last part of this paper, some instances when other nitrogen oxides were used as a probe molecule to characterize the zeolite structure, chemical properties of zeolites, and dynamics of small molecules were described on the basis of selected literature data reported recently.

  6. Radioembolization dosimetry : the road ahead

    NARCIS (Netherlands)

    Smits, Maarten L J; Elschot, Mattijs; Sze, Daniel Y; Kao, Yung H; Nijsen, JFW; Iagaru, Andre H; de Jong, Hugo W A M; van den Bosch, Maurice A A J; Lam, Marnix G E H

    2015-01-01

    Methods for calculating the activity to be administered during yttrium-90 radioembolization (RE) are largely based on empirical toxicity and efficacy analyses, rather than dosimetry. At the same time, it is recognized that treatment planning based on proper dosimetry is of vital importance for the o

  7. DLTS and EPR study of defects in H implanted silicon

    Energy Technology Data Exchange (ETDEWEB)

    Miksic, V.; Pivac, B. E-mail: pivac@rudjer.irb.hr; Rakvin, B.; Zorc, H.; Corni, F.; Tonini, R.; Ottaviani, G

    2002-01-01

    Single crystal CZ Si samples were implanted with hydrogen ions to the dose of 2E16 He ions/cm{sup 2} at room temperature and subsequently annealed in vacuum in the temperature interval from 100 to 900 deg. C. The aim of the experiment was to determine the conditions for bubble formation within the solid film, which may have important technological application. Defects produced in such samples were studied by deep-level transient spectroscopy (DLTS) and electron paramagnetic resonance (EPR) spectroscopy. It is shown that high dose hydrogen implantation produces vacancy-related and silicon selfinterstitial clusters. The latter are thought to be responsible for the formation of the weak displacement field. The annealing at higher temperatures creates multivacancy-related clusters responsible for the strong displacement field formation.

  8. Investigation of radical locations in various sesame seeds by CW EPR and 9-GHz EPR imaging.

    Science.gov (United States)

    Nakagawa, K; Hara, H

    2015-01-01

    We investigated the location of radical in various sesame seeds using continuous-wave (CW) electron paramagnetic resonance (EPR) and 9-GHz EPR imaging. CW EPR detected persistent radicals (single line) for various sesame seeds. The EPR linewidth of black sesame seeds was narrower than that of the irradiated white sesame seeds. A very small signal was detected for the white sesame seeds. Two-dimensional (2D) imaging using a 9-GHz EPR imager showed that radical locations vary for various sesame seeds. The paramagnetic species in black sesame seeds were located on the seed coat (skin) and in the hilum region. The signal with the highest intensity was obtained from the hilum part. A very low-intensity image was observed for the white sesame seeds. In addition, the 2D imaging of the irradiated white sesame seeds showed that free radicals were located throughout the entire seed. For the first time, CW EPR and 9-GHz EPR imaging showed the exact location of radical species in various sesame seeds.

  9. Computational and instrumental methods in EPR

    CERN Document Server

    Bender, Christopher J

    2006-01-01

    Computational and Instrumental Methods in EPR Prof. Bender, Fordham University Prof. Lawrence J. Berliner, University of Denver Electron magnetic resonance has been greatly facilitated by the introduction of advances in instrumentation and better computational tools, such as the increasingly widespread use of the density matrix formalism. This volume is devoted to both instrumentation and computation aspects of EPR, while addressing applications such as spin relaxation time measurements, the measurement of hyperfine interaction parameters, and the recovery of Mn(II) spin Hamiltonian parameters via spectral simulation. Key features: Microwave Amplitude Modulation Technique to Measure Spin-Lattice (T1) and Spin-Spin (T2) Relaxation Times Improvement in the Measurement of Spin-Lattice Relaxation Time in Electron Paramagnetic Resonance Quantitative Measurement of Magnetic Hyperfine Parameters and the Physical Organic Chemistry of Supramolecular Systems New Methods of Simulation of Mn(II) EPR Spectra: Single Cryst...

  10. Can EPR non-locality be geometrical?

    Energy Technology Data Exchange (ETDEWEB)

    Ne`eman, Y. [Tel-Aviv Univ. (Israel). Raymond and Beverly Sackler Faculty of Exact Sciences]|[Univ. of Texas, Austin, TX (United States). Center for Particle Physics; Botero, A. [Texas Univ., Austin, TX (United States)

    1995-10-01

    The presence in Quantum Mechanics of non-local correlations is one of the two fundamentally non-intuitive features of that theory. The non-local correlations themselves fall into two classes: EPR and Geometrical. The non-local characteristics of the geometrical type are well-understood and are not suspected of possibly generating acausal features, such as faster-than-light propagation of information. This has especially become true since the emergence of a geometrical treatment for the relevant gauge theories, i.e. Fiber Bundle geometry, in which the quantum non-localities are seen to correspond to pure homotopy considerations. This aspect is reviewed in section 2. Contrary-wise, from its very conception, the EPR situation was felt to be paradoxical. It has been suggested that the non-local features of EPR might also derive from geometrical considerations, like all other non-local characteristics of QM. In[7], one of the authors was able to point out several plausibility arguments for this thesis, emphasizing in particular similarities between the non-local correlations provided by any gauge field theory and those required by the preservation of the quantum numbers of the original EPR state-vector, throughout its spatially-extended mode. The derivation was, however, somewhat incomplete, especially because of the apparent difference between, on the one hand, the closed spatial loops arising in the analysis of the geometrical non-localities, from Aharonov-Bohm and Berry phases to magnetic monopoles and instantons, and on the other hand, in the EPR case, the open line drawn by the positions of the two moving decay products of the disintegrating particle. In what follows, the authors endeavor to remove this obstacle and show that as in all other QM non-localities, EPR is somehow related to closed loops, almost involving homotopy considerations. They develop this view in section 3.

  11. Identification of irradiated crab using EPR

    Energy Technology Data Exchange (ETDEWEB)

    Maghraby, A. [Radiation Dosimetry Department, National Institute for Standards (NIS), Ministry of Scientific Research, Haram, 12211- Giza, P.O. Box: 136 (Egypt)]. E-mail: maghrabism@yahoo.com

    2007-02-15

    EPR spectroscopy is a fast and powerful technique for the identification of irradiated food. Crab exoskeleton was divided into six parts: dactyl, cheliped, carapace, apron, swimming legs, and walking legs. Samples of the exoskeleton were prepared and irradiated to Cs-137 gamma radiation in the range (1.156-5.365 kGy). EPR spectra of unirradiated as well as irradiated samples were recorded and analyzed. Response to gamma radiation was plotted for each part of the exoskeleton, dactyl was found to be the most sensitive part, followed by the apron (38%), cheliped (37%), walking legs (30%), swimming legs (24%), and carapace (21%) relative to the dactyl response.

  12. Relocation of Dosimetry Service

    CERN Multimedia

    2007-01-01

    The Dosimetry Service is moving from Building 24 to Building 55 and will therefore be closed on Friday, March 30. From Monday, April 2 onwards you will find us in building 55/1-001. Please note that during that day we might still have some problems with the internet connections and cannot fully guarantee normal service procedures. The service's opening hours and telephone number will not change as a result of the move 8.30 - 12.00, afternoons closed Tel. 72155

  13. INDIVIDUAL DOSIMETRY SERVICE

    CERN Multimedia

    2000-01-01

    Personnel in the distribution groups Aleph, Delphi, L3, Opal who also work for other experiments than at LEP, should contact their dispatchers to explain their activities for the future, after LEP dismantling in order to be maintained on the regular distribution list at Individual Dosimetry ServiceWe inform all staffs and users under regular dosimetric control that the dosimeters for the monitoring period JULY/AUGUST are available from their usual dispatchers.Please have your films changed before the 10th of July.The colour of the dosimeter valid in JULY/AUGUST is PINK.

  14. Using rapid-scan EPR to improve the detection limit of quantitative EPR by more than one order of magnitude.

    Science.gov (United States)

    Möser, J; Lips, K; Tseytlin, M; Eaton, G R; Eaton, S S; Schnegg, A

    2017-08-01

    X-band rapid-scan EPR was implemented on a commercially available Bruker ELEXSYS E580 spectrometer. Room temperature rapid-scan and continuous-wave EPR spectra were recorded for amorphous silicon powder samples. By comparing the resulting signal intensities the feasibility of performing quantitative rapid-scan EPR is demonstrated. For different hydrogenated amorphous silicon samples, rapid-scan EPR results in signal-to-noise improvements by factors between 10 and 50. Rapid-scan EPR is thus capable of improving the detection limit of quantitative EPR by at least one order of magnitude. In addition, we provide a recipe for setting up and calibrating a conventional pulsed and continuous-wave EPR spectrometer for rapid-scan EPR. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Electron Paramagnetic Resonance Imaging: 2. Radiofrequency FT-EPR Imaging

    Indian Academy of Sciences (India)

    2016-08-01

    In this part we shall outline the challenges one faces whiledeveloping time-domain radiofrequency (RF) EPR imagingspectrometer for in vivo studies. Time-domain or FT-EPR isquite a different animal compared to the CW modality. Theevolution of FT-EPR instrumentation at the National CancerInstitute, NIH, USA and representative examples of applicationin cancer research are outlined in this article.

  16. Information from the Dosimetry Service

    CERN Multimedia

    2006-01-01

    Please note the following opening hours of the Service: From 31st July onwards: Every morning from 8:30 to 12:00 The Service is closed in the afternoons. We should like to remind you that dosimeters cannot be sent to customers by internal mail. Short-term dosimeters (VCTs) must always be returned to the Service after use and must not be left on the racks in the experimental areas or in the secretariats. Dosimetry Service Tel 72155 Bldg. 24 E 011 Dosimetry.service@cern.ch http://cern.ch/rp-dosimetry

  17. Monitoring enzymatic ATP hydrolysis by EPR spectroscopy.

    Science.gov (United States)

    Hacker, Stephan M; Hintze, Christian; Marx, Andreas; Drescher, Malte

    2014-07-14

    An adenosine triphosphate (ATP) analogue modified with two nitroxide radicals is developed and employed to study its enzymatic hydrolysis by electron paramagnetic resonance spectroscopy. For this application, we demonstrate that EPR holds the potential to complement fluorogenic substrate analogues in monitoring enzymatic activity.

  18. Internal dosimetry technical basis manual

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-20

    The internal dosimetry program at the Savannah River Site (SRS) consists of radiation protection programs and activities used to detect and evaluate intakes of radioactive material by radiation workers. Examples of such programs are: air monitoring; surface contamination monitoring; personal contamination surveys; radiobioassay; and dose assessment. The objectives of the internal dosimetry program are to demonstrate that the workplace is under control and that workers are not being exposed to radioactive material, and to detect and assess inadvertent intakes in the workplace. The Savannah River Site Internal Dosimetry Technical Basis Manual (TBM) is intended to provide a technical and philosophical discussion of the radiobioassay and dose assessment aspects of the internal dosimetry program. Detailed information on air, surface, and personal contamination surveillance programs is not given in this manual except for how these programs interface with routine and special bioassay programs.

  19. Radioembolization Dosimetry: The Road Ahead

    Energy Technology Data Exchange (ETDEWEB)

    Smits, Maarten L. J., E-mail: m.l.j.smits-3@umcutrecht.nl; Elschot, Mattijs [University Medical Center Utrecht, Department of Radiology and Nuclear Medicine (Netherlands); Sze, Daniel Y. [Stanford University School of Medicine, Division of Interventional Radiology (United States); Kao, Yung H. [Austin Hospital, Department of Nuclear Medicine (Australia); Nijsen, Johannes F. W. [University Medical Center Utrecht, Department of Radiology and Nuclear Medicine (Netherlands); Iagaru, Andre H. [Stanford University School of Medicine, Division of Nuclear Medicine and Molecular Imaging (United States); Jong, Hugo W. A. M. de; Bosch, Maurice A. A. J. van den; Lam, Marnix G. E. H. [University Medical Center Utrecht, Department of Radiology and Nuclear Medicine (Netherlands)

    2015-04-15

    Methods for calculating the activity to be administered during yttrium-90 radioembolization (RE) are largely based on empirical toxicity and efficacy analyses, rather than dosimetry. At the same time, it is recognized that treatment planning based on proper dosimetry is of vital importance for the optimization of the results of RE. The heterogeneous and often clustered intrahepatic biodistribution of millions of point-source radioactive particles poses a challenge for dosimetry. Several studies found a relationship between absorbed doses and treatment outcome, with regard to both toxicity and efficacy. This should ultimately lead to improved patient selection and individualized treatment planning. New calculation methods and imaging techniques and a new generation of microspheres for image-guided RE will all contribute to these improvements. The aim of this review is to give insight into the latest and most important developments in RE dosimetry and to suggest future directions on patient selection, individualized treatment planning, and study designs.

  20. Radioembolization dosimetry: the road ahead.

    Science.gov (United States)

    Smits, Maarten L J; Elschot, Mattijs; Sze, Daniel Y; Kao, Yung H; Nijsen, Johannes F W; Iagaru, Andre H; de Jong, Hugo W A M; van den Bosch, Maurice A A J; Lam, Marnix G E H

    2015-04-01

    Methods for calculating the activity to be administered during yttrium-90 radioembolization (RE) are largely based on empirical toxicity and efficacy analyses, rather than dosimetry. At the same time, it is recognized that treatment planning based on proper dosimetry is of vital importance for the optimization of the results of RE. The heterogeneous and often clustered intrahepatic biodistribution of millions of point-source radioactive particles poses a challenge for dosimetry. Several studies found a relationship between absorbed doses and treatment outcome, with regard to both toxicity and efficacy. This should ultimately lead to improved patient selection and individualized treatment planning. New calculation methods and imaging techniques and a new generation of microspheres for image-guided RE will all contribute to these improvements. The aim of this review is to give insight into the latest and most important developments in RE dosimetry and to suggest future directions on patient selection, individualized treatment planning, and study designs.

  1. Hanford internal dosimetry program manual

    Energy Technology Data Exchange (ETDEWEB)

    Carbaugh, E.H.; Sula, M.J.; Bihl, D.E.; Aldridge, T.L.

    1989-10-01

    This document describes the Hanford Internal Dosimetry program. Program Services include administrating the bioassay monitoring program, evaluating and documenting assessments of internal exposure and dose, ensuring that analytical laboratories conform to requirements, selecting and applying appropriate models and procedures for evaluating internal radionuclide deposition and the resulting dose, and technically guiding and supporting Hanford contractors in matters regarding internal dosimetry. 13 refs., 16 figs., 42 tabs.

  2. Dosimetry of iodoantipyrine.

    Science.gov (United States)

    Chu, R Y; Ekeh, S; Basmadjian, G

    1989-01-01

    Dosimetry of iodoantipyrine labeled with radioactive iodine was determined by measuring the biodistribution of 131I-iodoantipyrine in 41 female rabbits. Following administration of the radiopharmaceutical, subjects were killed at 0.5, 6, 12, 17, 24, 36, and 48 h. Organs and samples of tissues and body fluids were assayed. Results were corrected for physical decay. Exponential functions were employed to describe the time-concentration curves; representative value would be the biological half life of 9.96 +/- 0.55 h for blood. Cumulated activity estimates for 123I, 125I and 131I were then computed. Extrapolation to absorbed dose in humans followed the formulation of the Medical International Radiation Dose (MIRD) Committee of the Society of Nuclear Medicine. The whole body absorbed doses are 7 mu Gray, 5 mu Gray and 29 mu Gray per MBq of 123I, 125I, and 131I administered respectively.

  3. Medical dosimetry in Hungary

    Science.gov (United States)

    Turák, O.; Osvay, M.; Ballay, L.

    2012-09-01

    Radiation exposure of medical staff during cardiological and radiological procedures was investigated. The exposure of medical staff is directly connected to patient exposure. The aim of this study was to determine the distribution of doses on uncovered part of body of medical staff using LiF thermoluminescent (TL) dosimeters in seven locations. Individual Kodak film dosimeters (as authorized dosimetry system) were used for the assessment of medical staff's effective dose. Results achieved on dose distribution measurements confirm that wearing only one film badge under the lead apron does not provide enough information on the personal dose. The value of estimated annual doses on eye lens and extremities (fingers) were in good correlation with international publications.

  4. Strahlungsmessung und Dosimetrie

    CERN Document Server

    Krieger, Hanno

    2013-01-01

    „Strahlungsquellen und Dosimetrie“ ist Teil einer Lehrbuchreihe zur Strahlungsphysik und zum Strahlenschutz. Der erste Teil befasst sich mit den physikalischen Grundlagen der Strahlungsdetektoren und der Strahlungsmessung. Im zweiten Teil werden die Konzepte und Verfahren der klinischen Dosimetrie dargestellt. Der dritte Abschnitt erläutert ausführlich die Dosisverteilungen der klinisch angewendeten Strahlungsarten. Im vierten Teil werden weitere Messaufgaben der Strahlungsphysik einschließlich der Messsysteme für die Bildgebung mit Röntgenstrahlung dargestellt. Neben den grundlegenden Ausführungen enthält dieser Band im laufenden Text zahlreiche Tabellen und Grafiken zur technischen und medizinischen Radiologie, die bei der praktischen Arbeit sehr hilfreich sein können und 199 Übungsaufgaben mit Lösungen zur Vertiefung der Inhalte. Für die zweite Auflage wurden die Darstellungen der Elektronen- und der Protonendosimetrie sowie der bildgebenden Verfahren mit Computertomografen deutlich erweit...

  5. Fundamentals of Radiation Dosimetry

    Science.gov (United States)

    Bos, Adrie J. J.

    2011-05-01

    The basic concepts of radiation dosimetry are reviewed on basis of ICRU reports and text books. The radiation field is described with, among others, the particle fluence. Cross sections for indirectly ionizing radiation are defined and indicated is how they are related to the mass energy transfer and mass energy absorption coefficients. Definitions of total and restricted mass stopping powers of directly ionizing radiation are given. The dosimetric quantities, kerma, absorbed dose and exposure together with the relations between them are discussed in depth. Finally it is indicated how the absorbed dose can be measured with a calorimeter by measuring the temperature increase and with an ionisation chamber measuring the charge produced by the ionizing radiation and making use of the Bragg-Gray relation.

  6. Dosimetry considerations in phototherapy

    Energy Technology Data Exchange (ETDEWEB)

    Profio, A.E.; Doiron, D.R.

    Dosimetry in phototherapy involves a determination of the energy absorbed per unit mass of tissue, corrected for the quantum yield in a photochemical reaction. The dose rate in photochemotherapy of cancer with hematoporphyrin derivative and visible light is related to the extinction coefficient, quantum yield for singlet oxygen production, concentration of sensitizer and energy flux density at depth. Data or methods of determining these quantities are presented. Calculations have been performed for the energy flux density at depth, as a function of the total attenuation coefficient and ratio of scattering coefficient to total attenuation coefficient, for isotropic scattering in slab geometry. For small absorption, these depth dose curves exhibit a maximum within the tissue followed by an exponential decrease.

  7. Dosimetry considerations in phototherapy

    Energy Technology Data Exchange (ETDEWEB)

    Profio, A.E.; Doiron, D.R.

    1981-03-01

    Dosimetry in phototherapy involves a determination of the energy absorbed per unit mass of tissue, corrected for the quantum yield in a photochemical reaction. The dose rate in photochemotherapy of cancer with hematoporphyrin derivative and visible light is related to the extinction coefficient, quantum yield for singlet oxygen production, concentration of sensitizer and energy flux density at depth. Data or methods of determining these quantities are presented. Calculations have been performed for the energy flux density at depth, as a function of the total attenuation coefficient and ratio of scattering coefficient to total attenuation coefficient, for isotropic scattering in slab geometry. For small absorption, these depth dose curves exhibit a maximum within the tissue followed by an exponential decrease.

  8. Synergistic effect of nanoclay and EPR-g-MA on the properties of nylon6/EPR blends.

    Science.gov (United States)

    Mallick, Sumana; Das, Tanya; Das, C K; Khatua, B B

    2009-05-01

    The effect of EPR-g-MA, nanoclay and a combination of the two on phase morphology and properties of (70/30 w/w) nylon6/EPR blends prepared by melt processing technique has been studied. We found that the number average domain diameter (D(n)) of the dispersed EPR phase in the blend decreased in presence of EPR-g-MA, and clay. This observation indicated that nanoclay could be used as an effective compatibilizer in nylon6/EPR blend. X-ray diffraction study and TEM analysis of the blend/clay nanocomposites revealed the delaminated clay morphology and preferential location of the exfoliated clay platelets in nylon6 phase. Thus, selective dispersion of the clay platelets with delaminated morphology in the matrix phase acted as the barrier and thereby prevented the coalescence of dispersed EPR domains during melt processing. However, addition of nanoclay in the blend did not improve the impact property of the blend. Interestingly, the impact strength of the nylon6/EPR/EPR-g-MA/clay blend was much higher than the nylon6/EPR/EPR-g-MA and nylon6/EPR/clay blends at certain compositions with comparable D(n) values. This could be explained by assuming the presence of delaminated clay platelets at the interface, which were stiffer than the polymers. Hence, the bending energy of the interfaces was high.

  9. EPR in characterization of seeds paramagnetic species

    Energy Technology Data Exchange (ETDEWEB)

    Luiz, A.P.C.; Mauro, M.F.F.L.; Portugal, K.O.; Barbana, V.M.; Guedes, C.L.B.; Mauro, E. di; Carneiro, C.E.A.; Zaia, D.A.M.; Prete, C.E.C. [Universidade Estadual de Londrina (UEL), PR (Brazil)

    2011-07-01

    Full text. In Brazil, since 1970s, renewable fuel programs has been developed in order to replace petroleum. Today a program that has been discussed is the bio diesel, which intend to replace diesel fuel, fossil oil, to bio diesel, renewal fuel. As seeds are the basis for production of oil and consequently processed into bio diesel, the goal of this work is to characterize and compare paramagnetic species present in the seeds by Electron Paramagnetic Resonance (EPR). Samples used in this study were seeds of sorghum, barley, corn, peanuts, soy beans, cotton, wheat, oats, mustard, rice, sunflower and turnip. Some paramagnetic species present in soil was also investigated as goethite (FeOOH), hematite (Fe{sub 2}O{sub 3}), magnetite (Fe{sub 3}O{sub 4}), and ferrihydrite (Fe{sub 5}HO{sub 8} {center_dot} 4H{sub 2}O), since, these species present in appreciable quantities in the soil can be present in the seeds and analyzed for comparison. The characterization of these species is essential to understand the EPR seeds spectra. Each sample is placed in a thin quartz tube 4 mm in diameter, and it is inserted into the cavity of the spectrometer at room temperature, at low temperature (77 K) and variable temperature using liquid nitrogen flow and hot flow through a compressor air. It was used as standard Mg O:Mn{sup 2+}, which is also inserted into the cavity. Shortly after the potency is regulated, frequency, amplitude and sweep the field. The spectroscopic analysis by EPR X-band ({approx} 9:5GHz), were performed at the Fluorescence and Electron Paramagnetic Resonance Laboratory, Exact Sciences Center, State University of Londrina, Parana state, Brazil, through an EPR spectrometer JEOL brand (JES-PE-3X). In the EPR spectra, spectroscopic factor or g factor and line width were determined in paramagnetic species. Studies from several seeds with EPR technique detected in all of them presence of same complex of Fe{sup 3+} present in the goethite at g {approx} 2, and in the seeds

  10. EPR spectroscopy of nitrite complexes of methemoglobin.

    Science.gov (United States)

    Schwab, David E; Stamler, Jonathan S; Singel, David J

    2010-07-19

    The chemical interplay of nitrogen oxides (NO's) with hemoglobin (Hb) has attracted considerable recent attention because of its potential significance in the mechanism of NO-related vasoactivity regulated by Hb. An important theme of this interplay-redox coupling in adducts of heme iron and NO's-has sparked renewed interest in fundamental studies of FeNO(x) coordination complexes. In this Article, we report combined UV-vis and comprehensive electron paramagnetic resonance (EPR) spectroscopic studies that address intriguing questions raised in recent studies of the structure and affinity of the nitrite ligand in complexes with Fe(III) in methemoglobin (metHb). EPR spectra of metHb/NO(2)(-) are found to exhibit a characteristic doubling in their sharper spectral features. Comparative EPR measurements at X- and S-band frequencies, and in D(2)O versus H(2)O, argue against the assignment of this splitting as hyperfine structure. Correlated changes in the EPR spectra with pH enable complete assignment of the spectrum as deriving from the overlap of two low-spin species with g values of 3.018, 2.122, 1.45 and 2.870, 2.304, 1.45 (values for samples at 20 K and pH 7.4 in phosphate-buffered saline). These g values are typical of g values found for other heme proteins with N-coordinated ligands in the binding pocket and are thus suggestive of N-nitro versus O-nitrito coordination. The positions and shapes of the spectral lines vary only slightly with temperature until motional averaging ensues at approximately 150 K. The pattern of motional averaging in the variable-temperature EPR spectra and EPR studies of Fe(III)NO(2)(-)/Fe(II)NO hybrids suggest that one of two species is present in both of the alpha and beta subunits, while the other is exclusive to the beta subunit. Our results also reconfirm that the affinity of nitrite for metHb is of millimolar magnitude, thereby making a direct role for nitrite in physiological hypoxic vasodilation difficult to justify.

  11. EFFECT OF CADMIUM(II) ON FREE RADICALS IN DOPA-MELANIN TESTED BY EPR SPECTROSCOPY.

    Science.gov (United States)

    Zdybel, Magdalena; Pilawa, Barbara; Chodurek, Ewa

    2015-01-01

    Electron paramagnetic resonance (EPR) spectroscopy may be applied to examine interactions of melanin with metal ions and drugs. In this work EPR method was used to examination of changes in free radical system of DOPA-melanin--the model eumelanin after complexing with diamagnetic cadmium(II) ions. Cadmium(II) may affect free radicals in melanin and drugs binding by this polymer, so the knowledge of modification of properties and free radical concentration in melanin is important to pharmacy. The effect of cadmium(II) in different concentrations on free radicals in DOPA-melanin was determined. EPR spectra of DOPA-melanin, and DOPA-melanin complexes with cadmium(II) were measured by an X-band (9.3 GHz) EPR spectrometer produced by Radiopan (Poznań, Poland) and the Rapid Scan Unit from Jagmar (Krak6w, Poland). The DOPA (3,4-dihydroxyphenylalanine) to metal ions molar ratios in the reaction mixtures were 2:1, 1:1, and 1: 2. High concentrations of o-semiquinone (g ~2.0040) free radicals (~10(21)-10(22) spin/g) characterize DOPA-melanin and its complexes with cadmium(II). Formation of melanin complexes with cadmium(II) increase free radical concentration in DOPA-melanin. The highest free radical concentration was obtained for DOPA-melanin-cadmium(II) (1:1) complexes. Broad EPR lines with linewidths: 0.37-0.73 mT, were measured. Linewidths increase after binding of cadmium(II) to melanin. Changes of integral intensities and linewidths with increasing microwave power indicate the homogeneous broadening of EPR lines, independently on the metal ion concentration. Slow spin-lattice relaxation processes existed in all the tested samples, their EPR lines saturated at low microwave powers. Cadmium(II) causes fastening of spin-lattice relaxation processes in DOPA-melanin. The EPR results bring to light the effect of cadmium(II) on free radicals in melanin, and probably as the consequence on drug binding to eumelanin.

  12. Holographic EPR Pairs, Wormholes and Radiation

    CERN Document Server

    Chernicoff, Mariano; Pedraza, Juan F

    2013-01-01

    As evidence for the ER=EPR conjecture, it has recently been observed that the string that is holographically dual to an entangled quark-antiquark pair separating with (asymptotically) uniform acceleration has a wormhole on its worldsheet. We point out that a two-sided horizon and a wormhole actually appear for much more generic quark-antiquark trajectories, which is consistent with the fact that the members of an EPR pair need not be permanently out of causal contact. The feature that determines whether the causal structure of the string worldsheet is trivial or not turns out to be the emission of gluonic radiation by the dual quark and antiquark. In the strongly-coupled gauge theory, it is only when radiation is emitted that one obtains an unambiguous separation of the pair into entangled subsystems, and this is what is reflected on the gravity side by the existence of the worldsheet horizon.

  13. Full cycle rapid scan EPR deconvolution algorithm

    Science.gov (United States)

    Tseytlin, Mark

    2017-08-01

    Rapid scan electron paramagnetic resonance (RS EPR) is a continuous-wave (CW) method that combines narrowband excitation and broadband detection. Sinusoidal magnetic field scans that span the entire EPR spectrum cause electron spin excitations twice during the scan period. Periodic transient RS signals are digitized and time-averaged. Deconvolution of absorption spectrum from the measured full-cycle signal is an ill-posed problem that does not have a stable solution because the magnetic field passes the same EPR line twice per sinusoidal scan during up- and down-field passages. As a result, RS signals consist of two contributions that need to be separated and postprocessed individually. Deconvolution of either of the contributions is a well-posed problem that has a stable solution. The current version of the RS EPR algorithm solves the separation problem by cutting the full-scan signal into two half-period pieces. This imposes a constraint on the experiment; the EPR signal must completely decay by the end of each half-scan in order to not be truncated. The constraint limits the maximum scan frequency and, therefore, the RS signal-to-noise gain. Faster scans permit the use of higher excitation powers without saturating the spin system, translating into a higher EPR sensitivity. A stable, full-scan algorithm is described in this paper that does not require truncation of the periodic response. This algorithm utilizes the additive property of linear systems: the response to a sum of two inputs is equal the sum of responses to each of the inputs separately. Based on this property, the mathematical model for CW RS EPR can be replaced by that of a sum of two independent full-cycle pulsed field-modulated experiments. In each of these experiments, the excitation power equals to zero during either up- or down-field scan. The full-cycle algorithm permits approaching the upper theoretical scan frequency limit; the transient spin system response must decay within the scan

  14. Preparation-induced errors in EPR dosimetry of enamel: pre- and post-crushing sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Haskell, E.H.; Hayes, R.B.; Kenner, G.H. [Utah Univ., Salt Lake City, UT (United States). Radiobiology Div.

    1996-01-01

    Errors in dose estimation as a function of grain size for tooth enamel has been previously shown for beta irradiation after crushing. We tested the effect of gamma radiation applied to specimens before and after crushing. We extend the previous work in that we found that post-crushing irradiation altered the slope of the dose-response curve of the hydroxyapatite signal and produced a grain-size dependent offset. No changes in the slope of the dose-response curve were seen in enamel caps irradiated before crushing.

  15. Self-testing through EPR-steering

    Science.gov (United States)

    Šupić, Ivan; Hoban, Matty J.

    2016-07-01

    The verification of quantum devices is an important aspect of quantum information, especially with the emergence of more advanced experimental implementations of quantum computation and secure communication. Within this, the theory of device-independent robust self-testing via Bell tests has reached a level of maturity now that many quantum states and measurements can be verified without direct access to the quantum systems: interaction with the devices is solely classical. However, the requirements for this robust level of verification are daunting and require high levels of experimental accuracy. In this paper we discuss the possibility of self-testing where we only have direct access to one part of the quantum device. This motivates the study of self-testing via EPR-steering, an intermediate form of entanglement verification between full state tomography and Bell tests. Quantum non-locality implies EPR-steering so results in the former can apply in the latter, but we ask what advantages may be gleaned from the latter over the former given that one can do partial state tomography? We show that in the case of self-testing a maximally entangled two-qubit state, or ebit, EPR-steering allows for simpler analysis and better error tolerance than in the case of full device-independence. On the other hand, this improvement is only a constant improvement and (up to constants) is the best one can hope for. Finally, we indicate that the main advantage in self-testing based on EPR-steering could be in the case of self-testing multi-partite quantum states and measurements. For example, it may be easier to establish a tensor product structure for a particular party’s Hilbert space even if we do not have access to their part of the global quantum system.

  16. Upgrading the dosimetry at Ontario Hydro

    Energy Technology Data Exchange (ETDEWEB)

    Hirning, C.R. [Ontario Hydro, Whitby, ON (Canada). Health Physics Dept.

    1996-12-01

    Ontario Hydro has embarked upon a major programme to replace and upgrade its external dosimetry systems. In two year`s time, the utility expects to have two state-of-the-art dosimetry systems in place: a new TLD dosimetry of legal record that was designed nearly 30 years ago; and an electronic dosimetry system which could eventually replace the TLD as the primary system. (Author).

  17. Characterising an aluminium oxide dosimetry system.

    Science.gov (United States)

    Conheady, Clement F; Gagliardi, Frank M; Ackerly, Trevor

    2015-09-01

    In vivo dosimetry is recommended as a defence-in-depth strategy in radiotherapy treatments and is currently employed by clinics around the world. The characteristics of a new optically stimulated luminescence dosimetry system were investigated for the purpose of replacing an aging thermoluminescence dosimetry system for in vivo dosimetry. The stability of the system was not sufficient to satisfy commissioning requirements and therefore it has not been released into clinical service at this time.

  18. Interaction of formin FH2 with skeletal muscle actin. EPR and DSC studies.

    Science.gov (United States)

    Kupi, Tünde; Gróf, Pál; Nyitrai, Miklós; Belágyi, József

    2013-10-01

    Formins are highly conserved proteins that are essential in the formation and regulation of the actin cytoskeleton. The formin homology 2 (FH2) domain is responsible for actin binding and acts as an important nucleating factor in eukaryotic cells. In this work EPR and DSC were used to investigate the properties of the mDia1-FH2 formin fragment and its interaction with actin. MDia1-FH2 was labeled with a maleimide spin probe (MSL). EPR results suggested that the MSL was attached to a single SH group in the FH2. In DSC and temperature-dependent EPR experiments we observed that mDia1-FH2 has a flexible structure and observed a major temperature-induced conformational change at 41 °C. The results also confirmed the previous observation obtained by fluorescence methods that formin binding can destabilize the structure of actin filaments. In the EPR experiments the intermolecular connection between the monomers of formin dimers proved to be flexible. Considering the complex molecular mechanisms underlying the cellular roles of formins this internal flexibility of the dimers is probably important for manifestation of their biological functions.

  19. Retrospective assessment of radiation exposure using biological dosimetry: chromosome painting, electron paramagnetic resonance and the glycophorin a mutation assay.

    Science.gov (United States)

    Kleinerman, R A; Romanyukha, A A; Schauer, D A; Tucker, J D

    2006-07-01

    Biological monitoring of dose can contribute important, independent estimates of cumulative radiation exposure in epidemiological studies, especially in studies in which the physical dosimetry is lacking. Three biodosimeters that have been used in epidemiological studies to estimate past radiation exposure from external sources will be highlighted: chromosome painting or FISH (fluorescence in situ hybridization), the glycophorin A somatic mutation assay (GPA), and electron paramagnetic resonance (EPR) with teeth. All three biodosimeters have been applied to A-bomb survivors, Chernobyl clean-up workers, and radiation workers. Each biodosimeter has unique advantages and limitations depending upon the level and type of radiation exposure. Chromosome painting has been the most widely applied biodosimeter in epidemiological studies of past radiation exposure, and results of these studies provide evidence that dose-related translocations persist for decades. EPR tooth dosimetry has been used to validate dose models of acute and chronic radiation exposure, although the present requirement of extracted teeth has been a disadvantage. GPA has been correlated with physically based radiation dose after high-dose, acute exposures but not after low-dose, chronic exposures. Interindividual variability appears to be a limitation for both chromosome painting and GPA. Both of these techniques can be used to estimate the level of past radiation exposure to a population, whereas EPR can provide individual dose estimates of past exposure. This paper will review each of these three biodosimeters and compare their application in selected epidemiological studies.

  20. Nuclear accident dosimetry intercomparison studies.

    Science.gov (United States)

    Sims, C S

    1989-09-01

    Twenty-two nuclear accident dosimetry intercomparison studies utilizing the fast-pulse Health Physics Research Reactor at the Oak Ridge National Laboratory have been conducted since 1965. These studies have provided a total of 62 different organizations a forum for discussion of criticality accident dosimetry, an opportunity to test their neutron and gamma-ray dosimetry systems under a variety of simulated criticality accident conditions, and the experience of comparing results with reference dose values as well as with the measured results obtained by others making measurements under identical conditions. Sixty-nine nuclear accidents (27 with unmoderated neutron energy spectra and 42 with eight different shielded spectra) have been simulated in the studies. Neutron doses were in the 0.2-8.5 Gy range and gamma doses in the 0.1-2.0 Gy range. A total of 2,289 dose measurements (1,311 neutron, 978 gamma) were made during the intercomparisons. The primary methods of neutron dosimetry were activation foils, thermoluminescent dosimeters, and blood sodium activation. The main methods of gamma dose measurement were thermoluminescent dosimeters, radiophotoluminescent glass, and film. About 68% of the neutron measurements met the accuracy guidelines (+/- 25%) and about 52% of the gamma measurements met the accuracy criterion (+/- 20%) for accident dosimetry.

  1. Dosimetry of iodoantipyrine

    Energy Technology Data Exchange (ETDEWEB)

    Chu, R.Y.L.; Ekeh, S. (Oklahoma Univ., Oklahoma City, OK (USA). Dept. of Radiological Sciences; Veterans Administration Medical Center, Oklahoma City, OK (USA)); Basmadjian, G. (Oklahoma Univ., Oklahoma City, OK (USA). Dept. of Pharmaceutical Sciences)

    1989-12-01

    Dosimetry of iodoantipyrine labeled with radioactive iodine was determined by measuring the biodistribution of {sup 131}I-iodoantipyrine in 41 female rabbits. Following administration of the radiopharmaceutical, subjects were killed at 0.5, 6, 12, 17, 24, 36, and 48 h. Organs and samples of tissues and body fluids were assayed. Results were corrected for physical decay. Exponential functions were employed to describe the time-concentration curves; representative value would be the biological half life of 9.96+-0.55 h for blood. Cumulated activity estimates for {sup 123}I, {sup 125}I and {sup 131}I were then computed. Extrapolation to absorbed dose in humans followed the formulation of the Medical International Radiation Dose (MIRD) Committee of the Society of Nuclear Medicine. The whole body absorbed doses are 0.7 {mu}Gray, 0.5 {mu}Gray and 2.9 {mu}Gray per MBq of {sup 123}I, {sup 123}I, and {sup 131}I administered respectively. (orig.).

  2. Information from the Dosimetry Service

    CERN Multimedia

    2006-01-01

    Please note the following opening hours of the Service: In June: Every morning from 8:30 to 12:00 In July: Mondays, Wednesdays and Fridays from 8:30 to 11:30 Closed all day on Tuesdays and Thursdays From 31st July onwards: Every morning from 8:30 to 12:00 The Service is closed in the afternoons. We should like to remind you that dosimeters cannot be sent to customers by internal mail. Short-term dosimeters (VCTs) must always be returned to the Service after use and must not be left on the racks in the experimental areas or in the secretariats. Dosimetry Service Tel 72155 Bldg. 24 E 011 Dosimetry.service@cern.ch http://cern.ch/rp-dosimetry

  3. For information: Individual dosimetry service

    CERN Multimedia

    2004-01-01

    The service has noticed that there are dosimeter holders who have changed their activities and thus have no longer need of dosimeter as a permanent basis in their work (persons who go rarely to the controlled areas). The reduction of persons in the regular distribution list of dosimeters will lighten the work of the service (distribution, evaluation and consolidation of doses) as well as the work of the distributors, needless to say the economical input this would have for CERN. For the persons who only need a dosimeter temporarily we would like to remind that there is a quick and simple procedure to have one immediately from the Individual Dosimetry Service. Please contact the service (dosimetry.service@cern.ch) if you do not need a dosimeter regularly. Thank you for your cooperation. http://cern.ch/rp-dosimetry

  4. EPR study on gamma-irradiated fruits dehydrated via osmosis

    Energy Technology Data Exchange (ETDEWEB)

    Yordanov, N.D. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)]. E-mail: ndyepr@bas.bg; Aleksieva, K. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

    2007-06-15

    The shape and time stability of the electron paramagnetic resonance (EPR) spectra of non- and {gamma}-irradiated papaya, melon, cherry and fig samples dehydrated via osmosis are reported. It is shown that non-irradiated samples are generally EPR silent whereas {gamma}-irradiated exhibit 'sugar-like' EPR spectra. The recorded EPR spectra are monitored for a period of 7 months after irradiation (stored at low humidity and in the dark). The results suggest longer period of unambiguous identification of the radiation processing of osmose dehydrated fruits. Therefore, the Protocol EN 13708,2001 issued by CEN is fully applicable for the studied fruit samples.

  5. Eleventh DOE workshop on personnel neutron dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    Since its formation, the Office of Health (EH-40) has stressed the importance of the exchange of information related to and improvements in neutron dosimetry. This Workshop was the eleventh in the series sponsored by the Department of Energy (DOE). It provided a forum for operational personnel at DOE facilities to discuss current issues related to neutron dosimetry and for leading investigators in the field to discuss promising approaches for future research. A total of 26 papers were presented including the keynote address by Dr. Warren K. Sinclair, who spoke on, ``The 1990 Recommendations of the ICRP and their Biological Background.`` The first several papers discussed difficulties in measuring neutrons of different energies and ways of compensating or deriving correction factors at individual facilities. Presentations were also given by the US Navy and Air Force. Current research in neutron dosimeter development was the subject of the largest number of papers. These included a number on the development of neutron spectrometers. Selected papers were processed separately for inclusion in the Energy Science and Technology Database.

  6. Examination by EPR spectroscopy of free radicals in melanins isolated from A-375 cells exposed on valproic acid and cisplatin.

    Science.gov (United States)

    Chodurek, Ewa; Zdybel, Magdalena; Pilawa, Barbara; Dzierzewicz, Zofia

    2012-01-01

    Drug binding by melanin biopolymers influence the effectiveness of the chemotherapy, radiotherapy and photodynamic therapy. Free radicals of melanins take part in formation of their complex with drugs. The aim of this work was to determine the effect of the two compounds: valproic acid (VPA) and cisplatin (CPT) on free radicals properties of melanin isolated from A-375 melanoma cells. Free radicals were examined by an X-band (9.3 GHz) electron paramagnetic resonance (EPR) spectroscopy. EPR spectra were measured for the model synthetic eumelanin - DOPA-melanin, the melanin isolated from the control A-375 cells and these cells treated by VPA, CPT and both VPA and CPT. For all the examined samples broad EPR lines (deltaBpp: 0.48-0.68 mT) with g-factors of 2.0045-2.0060 characteristic for o-semiquinone free radicals were observed. Free radicals concentrations (N) in the tested samples, g-factors, amplitudes (A), integral intensities (I) and linewidths (deltaBpp) of the EPR spectra, were analyzed. The EPR lines were homogeneously broadened. Continuous microwave saturation of the EPR spectra indicated that slow spin-lattice relaxation processes existed in all the tested melanin samples. The relatively slowest spin-lattice relaxation processes characterized melanin isolated from A-375 cells treated with both VPA and CPT. The changes of the EPR spectra with increasing microwave power in the range of 2.2-70 mW were evaluated. Free radicals concentrations in the melanin from A-375 cells were higher than in the synthetic DOPA-melanin. The strong increase of free radicals concentration in the melanin from A-375 cells was observed after their treating by VPA. CPT also caused the increase of free radicals concentrations in the examined natural melanin. The free radicals concentration in melanin isolated from A-375 cells treated with both VPA and CPT was slightly higher than those in melanin from the control cells.

  7. Information from the Dosimetry Service

    CERN Multimedia

    2006-01-01

    CERN Staff and Users can now consult their dose records for an individual or an organizational unit with HRT. Please see more information on our web page http://cern.ch/rp-dosimetry. The Dosimetry Service is open every morning from 8.30 - 12.00, and closed in the afternoons. We would like to remind you that dosimeters cannot be sent to customers by internal mail. Short-term dosimeters (VCT's) must always be returned to the Service after use and must not be left on the racks in the experimental areas or in the secretariats.

  8. Information from the Dosimetry Service

    CERN Multimedia

    2006-01-01

    CERN Staff and Users can now consult their dose records for an individual or an organizational unit with HRT. Please see more information on our web page: http://cern.ch/rp-dosimetry. The Dosimetry Service is open every morning from 8.30 to 12.00 and is closed in the afternoons. We would like to remind you that dosimeters cannot be sent to customers by internal mail. Short-term dosimeters (VCT's) must always be returned to the Service after use and must not be left on the racks in the experimental areas or in the secretariats.

  9. Application of EPR spectroscopy to the examination of pro-oxidant activity of coffee.

    Science.gov (United States)

    Krakowian, Daniel; Skiba, Dominik; Kudelski, Adam; Pilawa, Barbara; Ramos, Paweł; Adamczyk, Jakub; Pawłowska-Góral, Katarzyna

    2014-05-15

    Free radicals present in coffee may be responsible for exerting toxic effects on an organism. The objectives of this work were to compare free radicals properties and concentrations in different commercially available coffees, in solid and liquid states, and to determine the effect of roasting on the formation of free radicals in coffee beans of various origins. The free radicals content of 15 commercially available coffees (solid and liquid) was compared and the impact of processing examined using electron paramagnetic resonance (EPR) spectroscopy at X-band (9.3 GHz). First derivative EPR spectra were measured at microwave power in the range of 0.7-70 mW. The following parameters were calculated for EPR spectra: amplitude (A), integral intensity (I), and line-width (ΔBpp); g-Factor was obtained from resonance condition. Our study showed that free radicals exist in green coffee beans (10(16) spin/g), roasted coffee beans (10(18) spin/g), and in commercially available coffee (10(17)-10(18) spin/g). Free radical concentrations were higher in solid ground coffee than in instant or lyophilised coffee. Continuous microwave saturation indicated homogeneous broadening of EPR lines from solid and liquid commercial coffee samples as well as green and roasted coffee beans. Slow spin-lattice relaxation processes were found to be present in all coffee samples tested, solid and liquid commercial coffees as well as green and roasted coffee beans. Higher free radicals concentrations were obtained for both the green and roasted at 240 °C coffee beans from Peru compared with those originating from Ethiopia, Brazil, India, or Colombia. Moreover, more free radicals occurred in Arabica coffee beans roasted at 240 °C than Robusta. EPR spectroscopy is a useful method of examining free radicals in different types of coffee. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Locations of radical species in black pepper seeds investigated by CW EPR and 9 GHz EPR imaging

    Science.gov (United States)

    Nakagawa, Kouichi; Epel, Boris

    2014-10-01

    In this study, noninvasive 9 GHz electron paramagnetic resonance (EPR)-imaging and continuous wave (CW) EPR were used to investigate the locations of paramagnetic species in black pepper seeds without further irradiation. First, lithium phthalocyanine (LiPC) phantom was used to examine 9 GHz EPR imaging capabilities. The 9 GHz EPR-imager easily resolved the LiPC samples at a distance of ∼2 mm. Then, commercially available black pepper seeds were measured. We observed signatures from three different radical species, which were assigned to stable organic radicals, Fe3+, and Mn2+ complexes. In addition, no EPR spectral change in the seed was observed after it was submerged in distilled H2O for 1 h. The EPR and spectral-spatial EPR imaging results suggested that the three paramagnetic species were mostly located at the seed surface. Fewer radicals were found inside the seed. We demonstrated that the CW EPR and 9 GHz EPR imaging were useful for the determination of the spatial distribution of paramagnetic species in various seeds.

  11. Public debate on the EPR reactor; Debat public sur le reacteur EPR

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-10-15

    In the framework of the new EPR European Pressurized Reactor implementation in France, the public asked the first Ministry on the protection of nuclear matters, transports and installations against the terrorism and the spiteful actions. This document provides information on the subject and shows the safety of the new reactor. (A.L.B.)

  12. Sistemas de salvaguardia en reactores EPR

    OpenAIRE

    2015-01-01

    En este documento se describe brevemente el funcionamiento de los diversos sistemas de una planta nuclear operada con un reactor de tipo PWR. Más concretamente, el proyecto se centra en una descripción exhaustiva de los sistemas de salvaguardia y seguridad que regulan el funcionamiento de un reactor de tipo EPR, así como la central nuclear que contiene a dicho reactor. El proceso ha consistido en clasificar y resumir los distintos sistemas que operan en dicha planta, estudiando sus caracterís...

  13. ANALYSIS OF EPR AND FISH STUDIES OF RADIATION DOSES IN PERSONS WHO LIVED IN THE UPPER REACHES OF THE TECHA RIVER

    Energy Technology Data Exchange (ETDEWEB)

    Degteva, M. O.; Shagina, N. B.; Shishkina, Elena A.; Vozilova, Alexandra; Volchkova, A. Y.; Vorobiova, M. I.; Wieser, Albrecht; Fattibene, Paola; Della Monaca, S.; Ainsbury, E.; Moquet, J.; Anspaugh, L. R.; Napier, Bruce A.

    2015-07-24

    Waterborne radioactive releases into the Techa River from the Mayak Production Association in Russia during 1949–1956 resulted in significant doses to about 30,000 persons who lived in downstream settlements. The residents were exposed to internal and external radiation. Two methods for reconstruction of the external dose are considered in this paper, electron paramagnetic resonance (EPR) measurements of teeth and fluorescence in situ hybridization (FISH) measurements of chromosome translocations in circulating lymphocytes. The main issue in the application of the EPR and FISH methods for reconstruction of the external dose for the Techa Riverside residents was strontium radioisotopes incorporated in teeth and bones that served as a source of confounding local exposures. In order to estimate and subtract doses from incorporated 89,90Sr, the EPR and FISH assays were supported by measurements of 90Sr-body burdens and estimates of 90Sr concentrations in dental tissues by the luminescence method. The resulting dose estimates derived from EPR and FISH measurements for residents of the upper Techa River were found to be consistent: the mean values vary from 510 – 550 mGy for the villages located close to the site of radioactive release to 130 – 160 mGy for the more distant villages. The upper bound of individual estimates for both methods is equal to 2.2 – 2.3 Gy. The EPR- and FISH-based dose estimates were compared with the doses calculated for the donors using the Techa River Dosimetry System (TRDS). The TRDS external dose assessments were based on the data on contamination of the Techa River floodplain, simulation of ai r kerma above the contaminated soil, age-dependent life-styles and individual residence histories. For correct comparison TRDS-based doses were calculated from two sources: external exposure from the contaminated environment and internal exposure from 137Cs incorporated in donors’ soft tissues. The TRDS-based absorbed doses in tooth enamel

  14. Dosimetry for Electron Beam Applications

    DEFF Research Database (Denmark)

    Miller, Arne

    1983-01-01

    This report describes two aspects of electron bean dosimetry, on one hand developaent of thin fil« dosimeters and measurements of their properties, and on the other hand developaent of calorimeters for calibration of routine dosimeters, e.g. thin films. Two types of radiochromic thin film...

  15. In aqua vivo EPID dosimetry

    NARCIS (Netherlands)

    Wendling, M.; McDermott, L.N.; Mans, A.; Olaciregui-Ruiz, I.; Pecharroman-Gallego, R.; Sonke, J.J.; Stroom, J.; Herk, M. van; Mijnheer, B.J.

    2012-01-01

    PURPOSE: At the Netherlands Cancer Institute--Antoni van Leeuwenhoek Hospital in vivo dosimetry using an electronic portal imaging device (EPID) has been implemented for almost all high-energy photon treatments of cancer with curative intent. Lung cancer treatments were initially excluded, because t

  16. In vivo dosimetry in brachytherapy

    DEFF Research Database (Denmark)

    Tanderup, Kari; Beddar, Sam; Andersen, Claus Erik;

    2013-01-01

    In vivo dosimetry (IVD) has been used in brachytherapy (BT) for decades with a number of different detectors and measurement technologies. However, IVD in BT has been subject to certain difficulties and complexities, in particular due to challenges of the high-gradient BT dose distribution and th...

  17. Portal dosimetry in wedged beams

    NARCIS (Netherlands)

    Spreeuw, H.; Rozendaal, R.; Camargo, P.; Mans, A.; Wendling, M.; Olaciregui-Ruiz, I.; Sonke, J.J.; Herk, M. van; Mijnheer, B.

    2015-01-01

    Portal dosimetry using electronic portal imaging devices (EPIDs) is often applied to verify high-energy photon beam treatments. Due to the change in photon energy spectrum, the resulting dose values are, however, not very accurate in the case of wedged beams if the pixel-to-dose conversion for the s

  18. Significant pulmonary response to a brief high-level, nose-only nitrogen dioxide exposure: an interspecies dosimetry perspective.

    Science.gov (United States)

    Elsayed, Nabil M; Gorbunov, Nikolai V; Mayorga, Maria A; Kagan, Valerian E; Januszkiewicz, Adolph J

    2002-10-01

    Brief, high-level nitrogen dioxide (NO(2)) exposures are major hazards during fires and heat-generating explosions. To characterize the lung response to a brief high-level NO(2) exposure, we exposed two groups (n = 5) of 325-375 g, male, Sprague-Dawley rats to either 200 +/- 5 ppm (376 +/- 9 mg/m(3)) NO(2) or room air for 15 min. The rats were nose-only exposed in a multiport exposure chamber fitted with pressure transducers to monitor their respiration during exposure. One hour after exposure, we euthanized the rats, collected blood samples, lavaged the lungs with warm saline, and then excised them. One lung lobe was cooled to -196 degrees C and used for low-temperature electron paramagentic resonance (EPR) analysis. The remainder was homogenized and used for biochemical analyses. Inspired minute ventilation (V(i)) during exposure decreased 59% (p < 0.05). Calculated total inspired dose was 0.880 mg NO(2). In lung lavage, both total and alveolar macrophage cell counts declined (approximately 75%, p < 0.05), but epithelial cell count increased 8.5-fold. Lung weight increased 40% (p < 0.05) after exposure. In the blood, potassium and methemoglobin increased 45 and 18% (p < 0.05), respectively; glucose, lactate, and total hemoglobin were not altered significantly. EPR analysis of lung tissue revealed hemoglobin oxidation and carbon-centered radical formation. Vitamins E and C and uric acid were depleted, and lipid peroxidation measured by three different methods (TBARS, conjugated dienes, and fluorescent peroxidation end products) was elevated, but total protein, DNA, and lipid contents were unchanged. These observations combined demonstrate that a brief (15 min) high-level (200 ppm) NO(2) exposure of rats was sufficient to cause significant damage. However, comparison of the exposure dose normalized to rat body weight with previously reported sheep and estimated human values revealed significant differences. This raises a question about interspecies dosimetry and

  19. THE RADIATION CROSSLINKING OF EPR/SBR BLEND

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wanxi; L(U) Yingtao; SUN Jiazhen

    1990-01-01

    The radiation crosslinking of EPR/SBR blend has been studied. A relationship between sol fraction and radiation dose for the different weight ratio polymer blends and the method to calculate βb value of EPR/SBR blend system have been established.

  20. EPR study on tomatoes before and after gamma-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Aleksieva, K. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Georgieva, L.; Tzvetkova, E. [Institute of Cryobiology and Food Technology, 1162 Sofia (Bulgaria); Yordanov, N.D. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)], E-mail: ndyepr@bas.bg

    2009-09-15

    The results from the EPR studies on fresh, air-dried and lyophilized tomato samples before and after gamma-irradiation are reported. Before irradiation fresh and air-dried tomatoes exhibit one singlet EPR line characterized with common g-factor of 2.0048{+-}0.0005, whereas freeze-dried tomato does not show any EPR spectrum. After irradiation, a typical 'cellulose-like' triplet EPR spectrum appears in all samples, attributed to cellulose free radicals, generated by gamma-irradiation. It consists of intense central line with g=2.0048{+-}0.0005 and two weak satellite lines separated ca. 3 mT left and right of it. In air-dried and lyophilized tomatoes the 'cellulose-like' EPR spectrum is superimposed by an additional partly resolved carbohydrate spectrum. Fading measurements of the radiation-induced EPR signals indicate that the intensity of the EPR spectra of air-dried and freeze-dried tomato are reduced to about 50% after 50 days, whereas those of fresh irradiated tomatoes kept at 4 {sup o}C fade completely in 15 days. The reported results unambiguously show that the presence of two satellite lines in the EPR 'cellulose-like' spectra of tomato samples can be used for identification of radiation processing.

  1. Quantum Encryption Protocol Based on Continuous Variable EPR Correlations

    Institute of Scientific and Technical Information of China (English)

    HE Guang-Qiang; ZENG Gui-Hua

    2006-01-01

    A quantum encryption protocol based on Gaussian-modulated continuous variable EPR correlations is proposed. The security is guaranteed by continuous variable EPR entanglement correlations produced by nondegenerate optical parametric amplifier (NOPA). For general beam splitter eavesdropping strategy, the mutual information Ⅰ(α, ε)between Alice and Eve is calculated by employing Shannon information theory. Finally the security analysis is presented.

  2. EPR and NMR spectroscopy on spin-labeled proteins

    NARCIS (Netherlands)

    Finiguerra, Michelina Giuseppina

    2011-01-01

    Spin labeling and electron paramagnetic resonance (EPR) have been employed to study structure and dynamics of proteins. The surface polarity of four single cysteine mutants of the Zn-azurin in frozen solution were studied using 275 GHz EPR (J-band), with the advantage compared to 9 GHz (X-band) and

  3. Which Parts of a Clinical Process EPR Needs Special Configuration

    DEFF Research Database (Denmark)

    Barlach, Anders; Simonsen, Jesper

    2007-01-01

    Subject: Which parts of an electronic patient record (EPR) can initially form a stable standard solution to be used by all clinicians? And which parts of an EPR can we predict needs initial as well as on-going re-configuration to meet the needs from diverse medical specialties. Purpose: To analyz...

  4. Plutonium worker dosimetry.

    Science.gov (United States)

    Birchall, Alan; Puncher, M; Harrison, J; Riddell, A; Bailey, M R; Khokryakov, V; Romanov, S

    2010-05-01

    Epidemiological studies of the relationship between risk and internal exposure to plutonium are clearly reliant on the dose estimates used. The International Commission on Radiological Protection (ICRP) is currently reviewing the latest scientific information available on biokinetic models and dosimetry, and it is likely that a number of changes to the existing models will be recommended. The effect of certain changes, particularly to the ICRP model of the respiratory tract, has been investigated for inhaled forms of (239)Pu and uncertainties have also been assessed. Notable effects of possible changes to respiratory tract model assumptions are (1) a reduction in the absorbed dose to target cells in the airways, if changes under consideration are made to the slow clearing fraction and (2) a doubling of absorbed dose to the alveolar region for insoluble forms, if evidence of longer retention times is taken into account. An important factor influencing doses for moderately soluble forms of (239)Pu is the extent of binding of dissolved plutonium to lung tissues and assumptions regarding the extent of binding in the airways. Uncertainty analyses have been performed with prior distributions chosen for application in epidemiological studies. The resulting distributions for dose per unit intake were lognormal with geometric standard deviations of 2.3 and 2.6 for nitrates and oxides, respectively. The wide ranges were due largely to consideration of results for a range of experimental data for the solubility of different forms of nitrate and oxides. The medians of these distributions were a factor of three times higher than calculated using current default ICRP parameter values. For nitrates, this was due to the assumption of a bound fraction, and for oxides due mainly to the assumption of slower alveolar clearance. This study highlights areas where more research is needed to reduce biokinetic uncertainties, including more accurate determination of particle transport rates

  5. In vivo dosimetry with L-alpha-alanine

    Energy Technology Data Exchange (ETDEWEB)

    Boey, R.; Van Der Velden, K. [Industriele Hogeschool van het Gemeenschapsonderwijs Limburg, Hasselt (Belgium); Schaeken, B. [Algemeen Ziekenhuis Middelheim, Antwerp (Belgium). Dept. of Radiotherapy

    1995-12-01

    When organic substances are irradiated, stable electrons can be formed. The concentration of these electrons is detected via electron paramagnetic resonance (EPR), a non-destructive form of dosimetry. L-alpha-alanine is extremely suited as a detector because of its high stability and high yield of unpaired electrons. With an EMS 104 spectrometer, we measure the peak-to-peak value of the first derivate of the resonance-spectrum. This value is proportional to the concentration of unpaired electrons and therefore with the absorbed dose. Prior to the in vivo measurements in teletherapy, a calibration curve had to be established. This clearly showed a linear relationship between the EPR-signal and the absorbed dose, except for very low dose where precision was low (20% 1 sd). This indicates that the background signal of the dosimeter is strongly orientation dependent. For this reason it was decided to use pre-irradiated detectors. A number of in vivo measurements has been performed. It was found that the error propagation plays a major role in the calculation of the measured absorbed dose, in the range 1 Gy-6 Gy. Contrary to in vivo measurements in brachytherapy, where higher doses are measured, large uncertainties (30% 1 sd) on the entry dose calculations were observed. For this reason, it is recommended to use a statistical method of reducing this standard deviation to an acceptable level. The proposed method, consisting of 2 detectors and the usage of weight coefficients on our standard deviations, gave promising results. However, theoretical calculations and in vivo measurements show that this method is still not satisfactory to reduce the uncertainty to an acceptable standard in clinical situations.

  6. Use of the Frank sequence in pulsed EPR

    DEFF Research Database (Denmark)

    Tseitlin, Mark; Quine, Richard W.; Eaton, Sandra S.;

    2011-01-01

    The Frank polyphase sequence has been applied to pulsed EPR of triarylmethyl radicals at 256MHz (9.1mT magnetic field), using 256 phase pulses. In EPR, as in NMR, use of a Frank sequence of phase steps permits pulsed FID signal acquisition with very low power microwave/RF pulses (ca. 1.5m......W in the application reported here) relative to standard pulsed EPR. A 0.2mM aqueous solution of a triarylmethyl radical was studied using a 16mm diameter cross-loop resonator to isolate the EPR signal detection system from the incident pulses. Keyword: Correlation spectroscopy,Multi-pulse EPR,Low power pulses...

  7. EPR study of phenolic radical stabilization by grafting on SiO 2

    Science.gov (United States)

    Panagiota, Stathi; Louloudi, Maria; Deligiannakis, Yiannis

    2009-04-01

    A hybrid [SiO 2-GA] material has been synthesized by grafting Gallic acid (3,4,5-trihydroxybenzoic acid, GA) on SiO 2 via formation of amide bonds between amine groups on aminopropyl-silica and the carboxyl group of GA. The spatial fixation of GA prevents polymerization effects. EPR spectroscopy shows that GA radicals on [SiO 2-GA] show remarkable stability, comparable to that previously observed only for radicals in biological matrices on in soil organic matter. EPR reveals a bundle-like organization of the GA molecules on [SiO 2-GA] material. The relation of these factors to the enhanced radical stability is discussed.

  8. Results from 2010 Caliban Criticality Dosimetry Intercomparison

    Energy Technology Data Exchange (ETDEWEB)

    Veinot, K. G.

    2011-10-12

    The external dosimetry program participated in a criticality dosimetry intercomparison conducted at the Caliban facility in Valduc, France in 2010. Representatives from the dosimetry and instrumentation groups were present during testing which included irradiations of whole-body beta/gamma (HBGT) and neutron thermoluminescent dosimeters (TLDs), a fixed nuclear accident dosimeter (FNAD), electronic alarming dosimeters, and a humanoid phantom filled with reference man concentrations of sodium. This report reviews the testing procedures, preparations, irradiations, and presents results of the tests.

  9. Membrane remodeling by amyloidogenic and non-amyloidogenic proteins studied by EPR

    Science.gov (United States)

    Varkey, Jobin; Langen, Ralf

    2017-07-01

    The advancement in site-directed spin labeling of proteins has enabled EPR studies to expand into newer research areas within the umbrella of protein-membrane interactions. Recently, membrane remodeling by amyloidogenic and non-amyloidogenic proteins has gained a substantial interest in relation to driving and controlling vital cellular processes such as endocytosis, exocytosis, shaping of organelles like endoplasmic reticulum, Golgi and mitochondria, intracellular vesicular trafficking, formation of filopedia and multivesicular bodies, mitochondrial fusion and fission, and synaptic vesicle fusion and recycling in neurotransmission. Misregulation in any of these processes due to an aberrant protein (mutation or misfolding) or alteration of lipid metabolism can be detrimental to the cell and cause disease. Dissection of the structural basis of membrane remodeling by proteins is thus quite necessary for an understanding of the underlying mechanisms, but it remains a formidable task due to the difficulties of various common biophysical tools in monitoring the dynamic process of membrane binding and bending by proteins. This is largely since membranes generally complicate protein structure analysis and this problem is amplified for structural analysis in the presence of different types of membrane curvatures. Recent EPR studies on membrane remodeling by proteins show that a significant structural information can be generated to delineate the role of different protein modules, domains and individual amino acids in the generation of membrane curvature. These studies also show how EPR can complement the data obtained by high resolution techniques such as X-ray and NMR. This perspective covers the application of EPR in recent studies for understanding membrane remodeling by amyloidogenic and non-amyloidogenic proteins that is useful for researchers interested in using or complimenting EPR to gain better understanding of membrane remodeling. We also discuss how a single

  10. Asymmetric EPR entanglement in continuous variable systems

    CERN Document Server

    Wagner, Katherine; Armstrong, Seiji; Morizur, Jean-Francois; Lam, Ping Koy; Bachor, Hans-Albert

    2012-01-01

    Continuous variable entanglement can be produced in nonlinear systems or via interference of squeezed states. In many of optical systems, such as parametric down conversion or interference of optical squeezed states, production of two perfectly symmetric subsystems is usually used for demonstrating the existence of entanglement. This symmetry simplifies the description of the concept of entanglement. However, asymmetry in entanglement may arise naturally in a real experiment, or be intentionally introduced in a given quantum information protocol. These asymmetries can emerge from having the output beams experience different losses and environmental contamination, or from the availability of non-identical input quantum states in quantum communication protocols. In this paper, we present a visualisation of entanglement using quadrature amplitude plots of the twin beams. We quantitatively discuss the strength of asymmetric entanglement using EPR and inseparability criteria and theoretically show that the optimal...

  11. MISTI Shielding and Dosimetry Experiment Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Reliable on-orbit dosimetry is necessary for understanding effects of space radiation environments on spacecraft microelectronics performance and comparison of...

  12. Identification of gamma-irradiated fruit juices by EPR spectroscopy

    Science.gov (United States)

    Aleksieva, K. I.; Dimov, K. G.; Yordanov, N. D.

    2014-10-01

    The results of electron paramagnetic resonance (EPR) study on commercially available juices from various fruits and different fruit contents: 25%, 40%, 50%, and 100%, homemade juices, nectars and concentrated fruit syrups, before and after gamma-irradiation are reported. In order to remove water from non- and irradiated samples all juices and nectars were filtered; the solid residue was washed with alcohol and dried at room temperature. Only concentrated fruit syrups were dried for 60 min at 40 °C in a standard laboratory oven. All samples under study show a singlet EPR line with g=2.0025 before irradiation with exception of concentrated fruit syrups, which are EPR silent. Irradiation of juice samples gives rise to complex EPR spectra which gradually transferred to "cellulose-like" EPR spectrum from 25% to 100% fruit content. Concentrated fruit syrups show typical "sugar-like" spectra due to added saccharides. All EPR spectra are characteristic and can prove radiation treatment. The fading kinetics of radiation-induced EPR signals were studied for a period of 60 days after irradiation.

  13. Fifth personnel dosimetry intercomparison study

    Energy Technology Data Exchange (ETDEWEB)

    Sims, C.S.

    1980-02-01

    The fifth Personnel Dosimetry Intercomparison Study (PDIS) was conducted at the Oak Ridge National Laboratory's (ORNL) Dosimetry Applications Research (DOSAR) facility on March 20-22, 1979. This study is the latest PDIS in the continuing series started at the DOSAR facility in 1974. The PDIS is a three day study, typically in March, where personnel dosimeters are mailed to the DOSAR facility, exposed to a range of low-level neutron radiation doses (1 to 15 mSv or equivalently, 100 to 1500 mrem) and neutron-to-gamma ratios (1:1-10:1) using the Health Physics Research Reactor (HPRR) as the radiation source, and returned to the participants for evaluation. This report is a summary and analysis of the results reported by the various participants. The participants are able to intercompare their results with those of others who made dose measurements under identical experimental conditions.

  14. Gel dosimetry for conformal radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Gambarini, G. [Department of Physics of the University and INFN, Milan (Italy)]. e-mail: grazia.gambarini@mi.infn.it

    2005-07-01

    With the continuum development of conformal radio therapies, aimed at delivering high dose to tumor tissue and low dose to the healthy tissue around, the necessities has appeared of suitable improvement of dosimetry techniques giving the possibility of obtaining dose images to be compared with diagnostic images. Also if wide software has been developed for calculating dose distributions in the fields of various radiotherapy units, experimental verifications are necessary, in particular in the case of complex geometries in conformal radiotherapy. Gel dosimetry is a promising method for imaging the absorbed dose in tissue-equivalent phantoms, with the possibility of 3D reconstruction of the spatial dose distribution, with milli metric resolution. Optical imaging of gel dosimeters, based on visible light absorbance analysis, has shown to be a reliable technique for achieving dose distributions. (Author)

  15. NOTE FROM THE DOSIMETRY SERVICE

    CERN Multimedia

    2002-01-01

    During March, the Dosimetry Service will be opened from 8h30 to 12h in the morning and closed every afternoon.   We have established that many people, who are provided regularly with a personal dosimeter (film badge), have changed their activity and do not need it anymore, because they do not, or only exceptionally, enter controlled areas. If you are one of these persons, please contact the Personal Dosimeter Service (tel: 72155). There is a simplified procedure for obtaining a dosimeter if you have an immediate need for short-term visits in controlled areas. A reduction of the number of persons on the regular distribution list of dosimeters would decrease our and the distributors workload. It would also contribute to significant savings in the dosimetry, and thus CERN, budget. We thank you in advance for your understanding and for your collaboration.

  16. Dosimetry for the external radiation therapy. Dosimetry with alanine; Dosimetrie fuer die externe Strahlentherapie. Dosimetrie mit Alanin

    Energy Technology Data Exchange (ETDEWEB)

    Anton, Mathias [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany). Arbeitsgruppe ' Alanin-Dosimetrie'

    2013-06-15

    The alanine-ESR dosimetry in the PTB is described. The response power of alanine related to the water energy dose for X-rays with average energy of 10-1000 keV is presented. Furthermore the application of alanine for the quality assurance in the radiation therapy is described by means of the prostate irradiation and the therapy of a tumor in the neck region as examples. (HSI)

  17. Applying the conventional moving average filter for estimation of low radiation doses using EPR spectroscopy: Benefits and drawbacks

    Energy Technology Data Exchange (ETDEWEB)

    Maghraby, Ahmed M., E-mail: maghrabism@yahoo.com [National Institute of Standards (NIS), Radiation Dosimetry Department, Ministry of Scientific Research, Tersa Street, P.O. Box 136, Giza, Haram 12211 (Egypt); Physics Department, Faculty of Science and Humanities, Salman Bin AbdulAziz University, Alkharj (Saudi Arabia)

    2014-02-11

    Alanine/EPR is the most common dosimetry system for high radiation doses because of its high stability and wide linear response, however, use of alanine in most of medical applications still require special sophisticated methodologies and techniques in order to extend alanine detection limit to low levels of radiation doses. One of these techniques is the use of digital processing of acquired alanine spectra for enhancing useful components in spectra while useless features are suppressed. Simple moving average filter (MA) impacts on alanine EPR spectra have been studied in terms of peak-to-peak height, peak-to-peak line width, and associated uncertainty. Three types of the used filter were investigated: upward MA, central MA, and downward MA filters, effects of each on the peak position for different values of filter width were studied. It was found that MA filter always lead to the reduction in signal intensity and the increase of line width of the central peak of alanine spectrum. Peak position also changes in cases of the upward MA and downward MA filters while no significant changes were observed in the case of central MA. Uncertainties associated to the averaging process were evaluated and plotted versus the filter width resulting in a linear relationship. Filter width value should be carefully selected in order to avoid probable distortion in processed spectra while gaining less noisy spectra with less associated uncertainties.

  18. FID detection of EPR and ENDOR spectra at high microwave frequencies.

    Science.gov (United States)

    Blok, H; Akimoto, I; Milikisyants, S; Gast, P; Groenen, E J J; Schmidt, J

    2009-11-01

    High-frequency pulsed EPR spectroscopy allows FID detection of EPR spectra owing to the short dead time that can be achieved. This FID detection is particularly attractive for EPR and ENDOR spectroscopy of paramagnetic species that exhibit inhomogeneously broadened EPR lines and short dephasing times. Experiments are reported for the metalloprotein azurin at 275 GHz.

  19. FID detection of EPR and ENDOR spectra at high microwave frequencies

    Science.gov (United States)

    Blok, H.; Akimoto, I.; Milikisyants, S.; Gast, P.; Groenen, E. J. J.; Schmidt, J.

    2009-11-01

    High-frequency pulsed EPR spectroscopy allows FID detection of EPR spectra owing to the short dead time that can be achieved. This FID detection is particularly attractive for EPR and ENDOR spectroscopy of paramagnetic species that exhibit inhomogeneously broadened EPR lines and short dephasing times. Experiments are reported for the metalloprotein azurin at 275 GHz.

  20. I-124 Imaging and Dosimetry

    Directory of Open Access Journals (Sweden)

    Russ Kuker

    2017-02-01

    Full Text Available Although radioactive iodine imaging and therapy are one of the earliest applications of theranostics, there still remain a number of unresolved clinical questions as to the optimization of diagnostic techniques and dosimetry protocols. I-124 as a positron emission tomography (PET radiotracer has the potential to improve the current clinical practice in the diagnosis and treatment of differentiated thyroid cancer. The higher sensitivity and spatial resolution of PET/computed tomography (CT compared to standard gamma scintigraphy can aid in the detection of recurrent or metastatic disease and provide more accurate measurements of metabolic tumor volumes. However the complex decay schema of I-124 poses challenges to quantitative PET imaging. More prospective studies are needed to define optimal dosimetry protocols and to improve patient-specific treatment planning strategies, taking into account not only the absorbed dose to tumors but also methods to avoid toxicity to normal organs. A historical perspective of I-124 imaging and dosimetry as well as future concepts are discussed.

  1. Dosimetry studies in Zaborie village.

    Science.gov (United States)

    Takada, J; Hoshi, M; Endo, S; Stepanenko, V F; Kondrashov, A E; Petin, D; Skvortsov, V; Ivannikov, A; Tikounov, D; Gavrilin, Y; Snykov, V P

    2000-05-01

    Dosimetry studies in Zaborie, a territory in Russia highly contaminated by the Chernobyl accident, were carried out in July, 1997. Studies on dosimetry for people are important not only for epidemiology but also for recovery of local social activity. The local contamination of the soil was measured to be 1.5-6.3 MBq/m2 of Cs-137 with 0.7-4 microSv/h of dose rate. A case study for a villager presently 40 years old indicates estimations of 72 and 269 mSv as the expected internal and external doses during 50 years starting in 1997 based on data of a whole-body measurement of Cs-137 and environmental dose rates. Mean values of accumulated external and internal doses for the period from the year 1986 till 1996 are also estimated to be 130 mSv and 16 mSv for Zaborie. The estimation of the 1986-1996 accumulated dose on the basis of large scale ESR teeth enamel dosimetry provides for this village, the value of 180 mSv. For a short term visitor from Japan to this area, external and internal dose are estimated to be 0.13 mSv/9d (during visit in 1997) and 0.024 mSv/50y (during 50 years starting from 1997), respectively.

  2. EPR-based distance measurements at ambient temperature

    Science.gov (United States)

    Krumkacheva, Olesya; Bagryanskaya, Elena

    2017-07-01

    Pulsed dipolar (PD) EPR spectroscopy is a powerful technique allowing for distance measurements between spin labels in the range of 2.5-10.0 nm. It was proposed more than 30 years ago, and nowadays is widely used in biophysics and materials science. Until recently, PD EPR experiments were limited to cryogenic temperatures (T relaxation enhancement; RE). In this paper, we review the features of PD EPR and RE at ambient temperatures, in particular, requirements on electron spin phase memory time, ways of immobilization of biomolecules, the influence of a linker between the spin probe and biomolecule, and future opportunities.

  3. Pd+ ions in NaCl single crystal: EPR and optical studies

    Science.gov (United States)

    Badalyan, A. G.; Polak, K.; Rosa, J.

    2003-01-01

    EPR and optical absorption of Pd centres in as grown NaCl single crystal are reported. The EPR spectra show that palladium forms the Pd+ centre with d(x2-y2) wave function in the ground state. This centre formation and the accompanying distortion give rise to a superhyperfine interaction of the Pd+ ion with the nuclei of the four Cl- ligands in the plane perpendicular to the C-4 Symmetry axis. The results of the fitting of axial spin Hamiltonian parameters to the experimentally observed spectra give the following values at 12 K: g(parallel to) =2.85, g(perpendicular to) congruent to 2.15, A(parallel to) 29.8 x 10(-4)cm(-1), A(perpendicular to) = 5.9 x 10(-4)cm(-1). When the temperature increases, lines are getting broader, their amplitude decreases and a single line with g-value of g = 2.38 at g = 1/3(g(parallel to)+ 2g(perpendicular to)) appears, which demonstrates the known Jahn-Teller behaviour of d(9) ions EPR spectra.

  4. Applications of pulsed EPR spectroscopy to structural studies of sulfite oxidizing enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Eric L.; Astashkin, Andrei V.; Raitsimring, Arnold M.; Enemark, John H.

    2013-01-01

    Sulfite oxidizing enzymes (SOEs), including sulfite oxidase (SO) and bacterial sulfite dehydrogenase (SDH), catalyze the oxidation of sulfite (SO32-) to sulfate (SO42-). The active sites of SO and SDH are nearly identical, each having a 5-coordinate, pseudo-square-pyramidal Mo with an axial oxo ligand and three equatorial sulfur donor atoms. One sulfur is from a conserved Cys residue and two are from a pyranopterindithiolene (molybdopterin, MPT) cofactor. The identity of the remaining equatorial ligand, which is solvent-exposed, varies during the catalytic cycle. Numerous in vitro studies, particularly those involving electron paramagnetic resonance (EPR) spectroscopy of the Mo(V) states of SOEs, have shown that the identity and orientation of this exchangeable equatorial ligand depends on the buffer pH, the presence and concentration of certain anions in the buffer, as well as specific point mutations in the protein. Until very recently, however, EPR has not been a practical technique for directly probing specific structures in which the solvent-exposed, exchangeable ligand is an O, OH-, H2O, SO32-, or SO42- group, because the primary O and S isotopes (16O and 32S) are magnetically silent (I = 0). This review focuses on the recent advances in the use of isotopic labeling, variable-frequency high resolution pulsed EPR spectroscopy, synthetic model compounds, and DFT calculations to elucidate the roles of various anions, point mutations, and steric factors in the formation, stabilization, and transformation of SOE active site structures.

  5. Arbitrary waveform modulated pulse EPR at 200 GHz

    Science.gov (United States)

    Kaminker, Ilia; Barnes, Ryan; Han, Songi

    2017-06-01

    We report here on the implementation of arbitrary waveform generation (AWG) capabilities at ∼200 GHz into an Electron Paramagnetic Resonance (EPR) and Dynamic Nuclear Polarization (DNP) instrument platform operating at 7 T. This is achieved with the integration of a 1 GHz, 2 channel, digital to analog converter (DAC) board that enables the generation of coherent arbitrary waveforms at Ku-band frequencies with 1 ns resolution into an existing architecture of a solid state amplifier multiplier chain (AMC). This allows for the generation of arbitrary phase- and amplitude-modulated waveforms at 200 GHz with >150 mW power. We find that the non-linearity of the AMC poses significant difficulties in generating amplitude-modulated pulses at 200 GHz. We demonstrate that in the power-limited regime of ω1 10 MHz) spin manipulation in incoherent (inversion), as well as coherent (echo formation) experiments. Highlights include the improvement by one order of magnitude in inversion bandwidth compared to that of conventional rectangular pulses, as well as a factor of two in improvement in the refocused echo intensity at 200 GHz.

  6. EPR detection of foods preserved with ionizing radiation

    Science.gov (United States)

    Stachowicz, W.; Burlinska, G.; Michalik, J.

    1998-06-01

    The applicability of the epr technique for the detection of dried vegetables, mushrooms, some spices, flavour additives and some condiments preserved with ionizing radiation is discussed. The epr signals recorded after exposure to gamma rays and to beams of 10 MeV electrons from linac are stable, intense and specific enough as compared with those observed with nonirradiated samples and could be used for the detection of irradiation. However, stability of radiation induced epr signals produced in these foods depends on storage condition. No differences in shapes (spectral parameters) and intensities of the epr spectra recorded with samples exposed to the same doses of gamma rays ( 60Co) and 10 MeV electrons were observed

  7. Dosimetry requirements derived from the sterilization standards

    DEFF Research Database (Denmark)

    Miller, A.

    1998-01-01

    The main standards for radiation sterilization, ISO 11137 and EN 552, rest the documentation for the properly executed sterilization process on dosimetry. Both standards describe general requirements to the dosimetry system: The dose measurements must be traceable to national standards, the uncer...

  8. Electron Paramagnetic Resonance Imaging: 1. CW-EPR Imaging

    Indian Academy of Sciences (India)

    2016-07-01

    Twentieth century bore witness to remarkable scientists whohave advanced our understanding of the brain. Among them,EPR (Electron Paramagnetic Resonance) imaging is particularlyuseful in monitoring hypoxic zones in tumors which arehighly resistant to radiation and chemotherapeutic treatment.This first part of the article covers aspects of CW(continuous wave) imaging with details of FT (pulsed FourierTransform)-EPR imaging covered in Part 2, to be publishedin the next issue of Resonance.

  9. Most advanced HTP fuel assembly design for EPR

    Energy Technology Data Exchange (ETDEWEB)

    Francillon, Eric [AREVA - Framatome ANP, 10 rue Juliette Recamier - 69456 Lyon Cedex 06 (France); Kiehlmann, Horst-Dieter [AREVA - Framatome ANP GmbH, P.O. Box 3220, 91050 Erlangen (Germany)

    2006-07-01

    End 2003, the Finnish electricity utility Teollisuuden Voima Oy (TVO) signed the contract for building an EPR in Olkiluoto (Finland). Mid 2004, the French electricity utility EDF selected an EPR to be built in France. In 2005, Framatome ANP, an AREVA and Siemens company, announced that they will be pursuing a design certification in the U.S. The EPR development is based on the latest PWR product lines of former Framatome (N4) and Siemens Nuklear (Konvoi). As an introductory part, different aspects of the EPR core characteristics connected to fuel assembly design are presented. It includes means of ensuring reactivity control like hybrid AIC/B4C control rod absorbers and gadolinium as burnable absorber integrated in fuel rods, and specific options for in-core instrumentation, such as Aeroball type instrumentation. Then the design requirements for the EPR fuel assembly are presented in term of very high burnup capacity, rod cladding and fuel assembly reliability. Framatome ANP fuel assembly product characteristics meeting these requirements are then described. EPR fuel assembly design characteristics benefit from the experience feedback of the latest fuel assembly products designed within Framatome ANP, leading to resistance to assembly deformation, high fuel rod restraint and prevention of handling hazards. EPR fuel assembly design features the best components composing the cornerstones of the upgraded family of fuel assemblies that FRAMATOME ANP proposes today. This family is based on a set of common characteristics and associated features, which include the HMP grid as bottom end spacer, the MONOBLOC guide tube and the Robust FUELGUARD as lower tie plate, the use of the M5 Alloy, as cladding and structure material. This fully re-crystallized, ternary Zr-Nb-O alloy produces radically improved in-reactor corrosion, very low hydrogen uptake and growth and an excellent creep behavior, which are described there. EPR fuel assembly description also includes fuel rod

  10. EPR and NMR studies of amorphous aluminum borates

    NARCIS (Netherlands)

    Simon, S.; Pol, A. van der; Reijerse, E.J.; Kentgens, A.P.M.; Moorsel, G.J.M.P. van; Boer, E. de

    1994-01-01

    Amorphous aluminium borates, Al2(1–x)B2xO3 with O [less-than-or-eq]x[less-than-or-eq] 0.5, prepared from mixtures of aluminium nitrate, boric acid and glycerol, have been studied by EPR and 27Al MASNMR as a function of composition and heat-treatment temperature (Tt[less-than-or-eq] 860 °C). EPR stud

  11. Simultaneous acquisition of pulse EPR orientation selective spectra

    Science.gov (United States)

    Kaminker, Ilia; Florent, Marc; Epel, Boris; Goldfarb, Daniella

    2011-01-01

    High resolution pulse EPR methods are usually applied to resolve weak magnetic electron-nuclear or electron-electron interactions that are otherwise unresolved in the EPR spectrum. Complete information regarding different magnetic interactions, namely, principal components and orientation of principal axis system with respect to the molecular frame, can be derived from orientation selective pulsed EPR measurements that are performed at different magnetic field positions within the inhomogeneously broadened EPR spectrum. These experiments are usually carried out consecutively, namely a particular field position is chosen, data are accumulated until the signal to noise ratio is satisfactory, and then the next field position is chosen and data are accumulated. Here we present a new approach for data acquisition of pulsed EPR experiments referred to as parallel acquisition. It is applicable when the spectral width is much broader than the excitation bandwidth of the applied pulse sequence and it is particularly useful for orientation selective pulse EPR experiments. In this approach several pulse EPR measurements are performed within the waiting (repetition) time between consecutive pulse sequences during which spin lattice relaxation takes place. This is achieved by rapidly changing the main magnetic field, B0, to different values within the EPR spectrum, performing the same experiment on the otherwise idle spins. This scheme represents an efficient utilization of the spectrometer and provides the same spectral information in a shorter time. This approach is demonstrated on W-band orientation selective electron-nuclear double resonance (ENDOR), electron spin echo envelope modulation (ESEEM), electron-electron double resonance (ELDOR) - detected NMR and double electron-electron resonance (DEER) measurements on frozen solutions of nitroxides. We show that a factors of 3-6 reduction in total acquisition time can be obtained, depending on the experiment applied.

  12. EPR and NMR studies of amorphous aluminum borates

    NARCIS (Netherlands)

    Simon, S.; Pol, A. van der; Reijerse, E.J.; Kentgens, A.P.M.; Moorsel, G.J.M.P. van; Boer, E. de

    1994-01-01

    Amorphous aluminium borates, Al2(1–x)B2xO3 with O [less-than-or-eq]x[less-than-or-eq] 0.5, prepared from mixtures of aluminium nitrate, boric acid and glycerol, have been studied by EPR and 27Al MASNMR as a function of composition and heat-treatment temperature (Tt[less-than-or-eq] 860 °C). EPR stud

  13. Study of metalloproteins using continuous wave electron paramagnetic resonance (EPR).

    Science.gov (United States)

    Gambarelli, Serge; Maurel, Vincent

    2014-01-01

    Electron paramagnetic resonance (EPR) is an invaluable tool when studying systems with paramagnetic centers. It is a sensitive spectroscopic method, which can be used with dilute samples in aqueous buffer solutions. Here, we describe the basic procedure for recording an X-band EPR spectrum of a metalloprotein sample at low temperature. We also discuss basic optimization techniques to provide spectra with a high signal to noise ratio and minimum distortion.

  14. Lorentz symmetry breaking effects on relativistic EPR correlations

    Energy Technology Data Exchange (ETDEWEB)

    Belich, H. [Universidade Federal do Espirito Santo, Departamento de Fisica e Quimica, Vitoria, ES (Brazil); Furtado, C.; Bakke, K. [Universidade Federal da Paraiba, Departamento de Fisica, Caixa Postal 5008, Joao Pessoa, PB (Brazil)

    2015-09-15

    Lorentz symmetry breaking effects on relativistic EPR (Einstein-Podolsky-Rosen) correlations are discussed. From the modified Maxwell theory coupled to gravity, we establish a possible scenario of the Lorentz symmetry violation and write an effective metric for the Minkowski spacetime. Then we obtain the Wigner rotation angle via the Fermi-Walker transport of spinors and consider the WKB (Wentzel-Kramers-Brillouin) approximation in order to study the influence of Lorentz symmetry breaking effects on the relativistic EPR correlations. (orig.)

  15. Thermoluminescence and EPR studies of nanocrystalline Nd₂O₃:Ni²⁺ phosphor.

    Science.gov (United States)

    Umesh, B; Eraiah, B; Nagabhushana, H; Sharma, S C; Sunitha, D V; Nagabhushana, B M; Shivakumara, C; Rao, J L; Chakradhar, R P S

    2012-07-01

    Nanocrystalline Nd(2)O(3):Ni(2+) (2 mol%) phosphor has been prepared by a low temperature (∼400°C) solution combustion method, in a very short time (<5 min). Powder X-ray diffraction results confirm the single hexagonal phase of nanopowders. Scanning electron micrographs show that nanophosphor has porous nature and the particles are agglomerated. Transmission electron microscopy confirms the nanosize (20-25 nm) of the crystallites. The electron paramagnetic resonance (EPR) spectrum exhibits a symmetric absorption at g≈2.77 which suggests that the site symmetry around Ni(2+) ions is predominantly octahedral. The number of spins participating in resonance (N) and the paramagnetic susceptibility (χ) has been evaluated. Raman study show major peaks, which are assigned to F(g) and combination of A(g)+E(g) modes. Thermoluminescence (TL) studies reveal well resolved glow peaks at 169°C along with shoulder peak at around 236°C. The activation energy (E in eV), order of kinetics (b) and frequency factor (s) were estimated using glow peak shape method. It is observed that the glow peak intensity at 169°C increases linearly with γ-dose which suggest that Nd(2)O(3):Ni(2+) is suitable for radiation dosimetry applications. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. EPC projects for EPR Flamanville 3 NPP

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, J.I.; Polo, J.; Aymerich, E.; Cubian, B. [Nuclear Generation Department, Iberdrola Ingenieria y Construccion, Avda. Manoteras 20, 28050 Madrid (Spain)

    2010-07-01

    IBERDROLA Ingenieria y Construccion is carrying out a handful of activities in the EPR Flamanville 3 -FA3 NPP- context since 2007 matching oriented to position the company in the emerging marketplace of new nuclear power plants Generation III+, whose expectation for the next years is highly promising. IBERDROLA Ingenieria y Construccion leads 5 EPC -Engineering, Procurement and Commissioning- projects for FA3 NPP from the Nuclear Island till Sea Water Pumping Station as follows: - Design, procurement. fabrication, installation and testing of 21 shell and tubes heat-exchangers for the nuclear island. 12 out of these 17 HXs are conventional and will be designed according to ASME BPV code Section VIII and have to comply with PED 97/23/CE and ESPN. The remaining 5 HXs are nuclear and will be designed according to ASME BPV code Section III and have also to comply with PED and ESPN. - Design, procurement, fabrication and assembly of 9 demineralizers for different plant systems. Three of these Important To Safety (IPS) equipments have been manufactured according with ASME VIII codes and six of them with EN 13445 code plus additional requirements to comply with PED and final client requirements for nuclear island. - Design, fabrication and installation of qualified travelling water screening filters. The equipments furnished will be two nuclear safety qualified filters and associated equipment (cleaning water system and control system). Additionally some auxiliary devices such as grids, automatic trash rakes and stop gates are included in the contract. - Engineering, procurement, fabrication, erection and commissioning for the condensate treatment plant. This system includes a demineralizer tank, 5 filters, reactive injection mixer, pneumatic and manual valves, piping and instrumentation and control systems. - Engineering, procurement erection and commissioning for the electro-chlorination plant to protect the IPS piping for Condensate Water System for FA3. This system

  17. EPR study on non- and gamma-irradiated herbal pills

    Energy Technology Data Exchange (ETDEWEB)

    Aleksieva, K., E-mail: katerina_bas@abv.b [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Lagunov, O. [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Dimov, K. [Institute of Cryobiology and Food Technologies, 1162 Sofia (Bulgaria); Yordanov, N.D. [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

    2011-06-15

    The results of EPR studies on herbal pills of marigold, hawthorn, yarrow, common balm, tutsan, nettle and thyme before and after gamma-irradiation are reported. Before irradiation all samples exhibit one weak singlet EPR line with a g-factor of 2.0048{+-}0.0005. After irradiation herbal pills could be separated in two groups according to their EPR spectra. Radiation-induced free radicals in pills of marigold, yarrow, nettle, tutsan and thyme could be attributed mainly to saccharide excipients. Tablets of hawthorn and common balm show 'cellulose-like' EPR spectrum, superimposed on partly resolved carbohydrate spectrum, due to the active part (herb) and inulin, which is present in the pills as an excipient. Fading study of the radiation-induced EPR signals confirms that sugar radicals are more stable than cellulose species. The reported results show that the presence of characteristic EPR spectra of herbal pills due to excipients or active part can be used as unambiguous proof of radiation processing within 35 or more days after irradiation.

  18. EPR study on non- and gamma-irradiated herbal pills

    Science.gov (United States)

    Aleksieva, K.; Lagunov, O.; Dimov, K.; Yordanov, N. D.

    2011-06-01

    The results of EPR studies on herbal pills of marigold, hawthorn, yarrow, common balm, tutsan, nettle and thyme before and after gamma-irradiation are reported. Before irradiation all samples exhibit one weak singlet EPR line with a g-factor of 2.0048±0.0005. After irradiation herbal pills could be separated in two groups according to their EPR spectra. Radiation-induced free radicals in pills of marigold, yarrow, nettle, tutsan and thyme could be attributed mainly to saccharide excipients. Tablets of hawthorn and common balm show "cellulose-like" EPR spectrum, superimposed on partly resolved carbohydrate spectrum, due to the active part (herb) and inulin, which is present in the pills as an excipient. Fading study of the radiation-induced EPR signals confirms that sugar radicals are more stable than cellulose species. The reported results show that the presence of characteristic EPR spectra of herbal pills due to excipients or active part can be used as unambiguous proof of radiation processing within 35 or more days after irradiation.

  19. JENDL dosimetry file 99 (JENDL/D-99)

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Katsuhei [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Institute; Iguchi, Tetsuo [Nagoya Univ., Faculty of Engineering, Nagoya, Aichi (Japan); Iwasaki, Shin [Tohoku Univ., Faculty of Engineering, Sendai, Miyagi (JP)] [and others

    2002-01-01

    The JENDL Dosimetry File 99 (JENDL/D-99), which is a revised version of the JENDL Dosimetry File 91 (JENDL/D-91), has been compiled and released for the determination of neutron flux and energy spectra. This work was undertaken to remove the inconsistency between the cross sections and their covariances in JENDL/D-91 since the covariances were mainly taken from IRDF-85 although the cross sections were based on JENDL-3. Dosimetry cross sections have been evaluated for 67 reactions on 47 nuclides together with covariances. The cross sections for 34 major reactions and their covariances were simultaneously generated, and the remaining 33 reaction data were mainly taken from JENDL/D-91. Latest measurements were taken into account in the evaluation. The resultant evaluated data are given in the neutron energy region below 20 MeV in both of point-wise and group-wise files in the ENDF-6 format. In order to confirm the reliability of the evaluated data, several integral tests have been carried out: comparisons with average cross sections measured in fission neutron fields, fast/thermal reactor spectra, DT neutron fields and Li(d,n) neutron fields. It was found from the comparisons that the cross sections calculated from JENDL/D-99 are generally in good agreement with the measured data. The contents of JENDL/D-99 and the results of the integral tests are described in this report. All of the dosimetry cross sections are shown in a graphical form in the Appendix. (author)

  20. Application of EPR spectroscopy to examine free radicals evolution during storage of the thermally sterilized Ungentum ophthalmicum.

    Science.gov (United States)

    Ramos, Paweł; Pilawa, Barbara

    2016-06-24

    Free radicals formed during thermal sterilization of the Ungentum ophthalmicum were examined by an X-band EPR spectroscopy. The influence of storage time (15 min; 1, 2 and 3 days after heating) on free radical properties and concentrations in this sample was determined. Thermal sterilization was done according to the pharmaceutical norms. The first-derivative EPR spectra with g-values about 2 were measured with magnetic modulation of 100 kHz in the range of microwave power 2.2-70 mW. The changes of amplitudes (A) and linewidths (ΔBpp) with microwave powers were evaluated. Free radicals in concentration ∼10(17) spin/g were formed during heating of the tested Ungentum. Free radical concentration decreased with increase in storage time, and reached values ∼10(17) spin/g after 3 days from sterilization. The tested U. ophthalmicum should not be sterilized at a temperature of 160 °C because of the free radicals formation, or it should be used 3 days after heating, when free radicals were considerably quenched. Free radical properties remain unchanged during storage of the Ungentum. The EPR lines of the U. ophthalmicum were homogeneously broadened and their linewidths (ΔBpp) increased with increase in microwave power. EPR spectroscopy is useful to examine free radicals to optimize sterilization process and storage conditions of ophthalmologic samples.

  1. Arbitrated Quantum Signature protocol using EPR pairs

    Directory of Open Access Journals (Sweden)

    Jun Zhang

    2012-11-01

    Full Text Available Arbitrated signature provides that the signatory signs a message with his private key by quantum cryptography, while the signature receiver verifies the signature with the arbitrator’s assistance. In this work, security analysis was given to the arbitrated quantum signature (AQS and results showed that the receiver Bob and the attacker can forge the signature. Then this paper gives a new quantum one-time pads encryption method, which is suit for the quantum signature. At last, a new AQS protocol using Einstein-Podoisky-Rosen (EPR pairs is proposed. By using of  quantum key distribution (QKD and new quantum one-time pads, the new scheme can resist Shor’s attack. The new scheme has following advantages: (1 The scheme reduces the complexity of implementation and provides a higher efficiency in transmission; (2 Compares with some AQS schemes, the scheme can avoid being disavowed by the receiver; (3 Compares with other AQS schemes, the scheme also guarantees the arbitrator cannot forge the signature and it also ensure the receiver and other attacker cannot forge the signature.

  2. ESR dosimetry using eggshells and tooth enamel for accidental dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Oka, Toshihide; Yamanaka, Chihiro; Ikeya, Motoji [Department of Earth and Space Science, Faculty of Science, Osaka Univ., Toyonaka, Osaka (Japan)

    1997-07-01

    The CO{sub 2}{sup -} signal of eggshells showed a good dose linearity and was appropriate in the wide dose range from 1 to 10 kGy, while ESR signal of CO{sub 2}{sup -} in sea and fresh water shells were saturated at a dose od below 10 kGy. The minimum detectable dose and G-value of CO{sub 2}{sup -} in eggshells were estimated 0.3 Gy and 0.28, respectively. The lifetime of CO{sub 2}{sup -} in eggshells could not be determined exactly because of overlapping organic signals, however it is still sufficiently long for practical use as ESR dosimeter materials. Various bird`s or reptile`s eggshells would be available as natural retrospective ESR dosimeter materials after nuclear accidents. Eggshells will be useful for the food irradiation dosimetry in the dose range of about a few kGy. Tooth enamel is one of the most useful dosimeter materials in public at a accident because of its high sensitivity. ESR dosimetry will replace TLD in near future if the cost of an ESR reader is further reduced . (author)

  3. Radiation dosimetry by potassium feldspar

    Indian Academy of Sciences (India)

    Arun Pandya; S G Vaijapurkar; P K Bhatnagar

    2000-04-01

    The thermoluminescence (TL) properties of raw and annealed feldspar have been studied for their use in gamma dosimetry. The raw gamma exposed feldspar shows glow peaks at 120°C and 319°C. Gamma dose beyond 500 cGy can be measured without any significant fading even after 40 days of termination of exposure. The annealed feldspar shows a glow peak at 120°C after gamma exposure. This peak can be used to measure gamma doses beyond 25 cGy when the TL is measured after 24 h from termination of exposure.

  4. Relocation of the Dosimetry Service

    CERN Multimedia

    2007-01-01

    The Dosimetry Service is moving from Building 24 to Building 55 and will therefore be closed on Friday, 30 March. From Monday, 2 April onwards you will find us in Building 55/1-001. Please note that we cannot exclude problems with Internet connections on that day and are therefore unable to guarantee normal service. The Service's opening hours and telephone number will not change as a result of the move: Open from 8.30 - 12.00. Closed in the afternoons. Tel. 7 2155

  5. An Automated Biological Dosimetry System

    Science.gov (United States)

    Lorch, T.; Bille, J.; Frieben, M.; Stephan, G.

    1986-04-01

    The scoring of structural chromosome aberrations in peripheral human blood lymphocytes can be used in biological dosimetry to estimate the radiation dose which an individual has received. Especially the dicentric chromosome is a rather specific indicator for an exposure to ionizing radiation. For statistical reasons, in the low dose range a great number of cells must be analysed, which is a very tedious task. The resulting high cost of a biological dose estimation limits the application of this method to cases of suspected irradiation for which physical dosimetry is not possible or not sufficient. Therefore an automated system has been designed to do the major part of the routine work. It uses a standard light microscope with motorized scanning stage, a Plumbicon TV-camera, a real-time hardware preprocessor, a binary and a grey level image buffer system. All computations are performed by a very powerful multi-microprocessor-system (POLYP) based on a MIMD-architecture. The task of the automated system can be split in finding the metaphases (see Figure 1) at low microscope magnification and scoring dicentrics at high magnification. The metaphase finding part has been completed and is now in routine use giving good results. The dicentric scoring part is still under development.

  6. Path forward for dosimetry cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, P.J. [Sandia National Laboratories, Albuquerque, NM 87185-1146 (United States); Peters, C.D. [Sandia Staffing Alliance, Albuquerque, NM 87110 (United States)

    2011-07-01

    In the 1980's the dosimetry community embraced the need for a high fidelity quantification of uncertainty in nuclear data used for dosimetry applications. This led to the adoption of energy-dependent covariance matrices as the accepted manner of quantifying the uncertainty data. The trend for the dosimetry community to require high fidelity treatment of uncertainty estimates has continued to the current time where requirements on nuclear data are codified in standards such as ASTM E 1018. This paper surveys the current state of the dosimetry cross sections and investigates the quality of the current dosimetry cross section evaluations by examining calculated-to-experimental ratios in neutron benchmark fields. In recent years more nuclear-related technical areas are placing an emphasis on uncertainty quantification. With the availability of model-based cross sections and covariance matrices produced by nuclear data codes, some nuclear-related communities are considering the role these covariance matrices should play. While funding within the dosimetry community for cross section evaluations has been very meager, other areas, such as the solar-related astrophysics community and the US Nuclear Criticality Safety Program, have been supporting research in the area of neutron cross sections. The Cross Section Evaluation Working Group (CSEWG) is responsible for the creation and maintenance of the ENDF/B library which has been the mainstay for the reactor dosimetry community. Given the new trends in cross section evaluations, this paper explores the path forward for the US nuclear reactor dosimetry community and its use of the ENDF/B cross-sections. The major concern is maintenance of the sufficiency and accuracy of the uncertainty estimate when used for dosimetry applications. The two major areas of deficiency in the proposed ENDF/B approach are: 1) the use of unrelated covariance matrices in ENDF/B evaluations and 2) the lack of 'due consideration' of

  7. Application of the Electron paramagnetic resonance to the ionizing radiation dosimetry; Aplicacion de la Resonancia paramagnetica electronica a la dosimetria de las radiaciones ionizantes

    Energy Technology Data Exchange (ETDEWEB)

    Urena N, F. [Instituto Nacional de Investigaciones Nucleares, Km. 36.5 Carretera Mexico-Toluca, 52045 Salazar, Estado de Mexico (Mexico)

    2000-07-01

    The Electron Paramagnetic Resonance (EPR) is defined as the resonant absorption of electromagnetic energy in paramagnetic substances by the spin transition of a non-pairing electron between different energy levels in presence of a magnetic field. (Slighter, 1989). One of the more important characteristic of EPR is that the electron spin levels are subdivided by the electron interaction with the magnetic dipoles of the nearby nucleus giving occasion for a spectral structure called hyperfine structure. In this kind of interactions two limit cases are distinguished: 1. when the non-pairing electron is located in a central ion surrounded of atoms belonging to coordinate molecules. 2. When a non-pairing electron interactioning in the same form with a number of equivalent nucleus, which is common in organic radicals, these will give as result spectra. Some EPR spectrometer can be used to dosimetric purposes by free radicals via. In this work, it is presented the application of EPR to dosimetry of ionizing radiations by free radicals via which allows to determinations of high doses. (Author)

  8. Analysis of EPR and FISH studies of radiation doses in persons who lived in the upper reaches of the Techa River

    Energy Technology Data Exchange (ETDEWEB)

    Degteva, M.O.; Shagina, N.B.; Shishkina, E.A.; Vozilova, A.V.; Volchkova, A.Y.; Vorobiova, M.I. [Urals Research Center for Radiation Medicine, Chelyabinsk (Russian Federation); Wieser, A. [Helmholtz Centrum Munich, Neuherberg (Germany); Fattibene, P.; Della Monaca, S. [Instituto Superiore di Sanita, Rome (Italy); Ainsbury, E.; Moquet, J. [Public Health England, Chilton, Didcot (United Kingdom); Anspaugh, L.R. [University of Utah, Salt Lake City, UT (United States); Napier, B.A. [Pacific Northwest National Laboratory, Richland, WA (United States)

    2015-11-15

    Waterborne radioactive releases into the Techa River from the Mayak Production Association in Russia during 1949-1956 resulted in significant doses to about 30,000 persons who lived in downstream settlements. The residents were exposed to internal and external radiation. Two methods for reconstruction of the external dose are considered in this paper, electron paramagnetic resonance (EPR) measurements of teeth, and fluorescence in situ hybridization (FISH) measurements of chromosome translocations in circulating lymphocytes. The main issue in the application of the EPR and FISH methods for reconstruction of the external dose for the Techa Riverside residents was strontium radioisotopes incorporated in teeth and bones that act as a source of confounding local exposures. In order to estimate and subtract doses from incorporated {sup 89,90}Sr, the EPR and FISH assays were supported by measurements of {sup 90}Sr-body burdens and estimates of {sup 90}Sr concentrations in dental tissues by the luminescence method. The resulting dose estimates derived from EPR to FISH measurements for residents of the upper Techa River were found to be consistent: The mean values vary from 510 to 550 mGy for the villages located close to the site of radioactive release to 130-160 mGy for the more distant villages. The upper bound of individual estimates for both methods is equal to 2.2-2.3 Gy. The EPR- and FISH-based dose estimates were compared with the doses calculated for the donors using the most recent Techa River Dosimetry System (TRDS). The TRDS external dose assessments are based on the data on contamination of the Techa River floodplain, simulation of air kerma above the contaminated soil, age-dependent lifestyles and individual residence histories. For correct comparison, TRDS-based doses were calculated from two sources: external exposure from the contaminated environment and internal exposure from {sup 137}Cs incorporated in donors' soft tissues. It is shown here that the

  9. Introduction to radiological physics and radiation dosimetry

    CERN Document Server

    Attix, Frank Herbert

    2004-01-01

    A straightforward presentation of the broad concepts underlying radiological physics and radiation dosimetry for the graduate-level student. Covers photon and neutron attenuation, radiation and charged particle equilibrium, interactions of photons and charged particles with matter, radiotherapy dosimetry, as well as photographic, calorimetric, chemical, and thermoluminescence dosimetry. Includes many new derivations, such as Kramers X-ray spectrum, as well as topics that have not been thoroughly analyzed in other texts, such as broad-beam attenuation and geometrics, and the reciprocity theorem

  10. Effect of UV irradiation on free radicals in synthetic melanin and melanin biopolymer from Sepia officinalis – EPR examination

    Directory of Open Access Journals (Sweden)

    Zdybel Magdalena

    2015-07-01

    Full Text Available Free radicals in synthetic melanin and melanin from Sepia officinalis were studied by electron paramagnetic resonance (EPR spectroscopy. The effect of time of ultraviolet (UV irradiation on free radicals in these melanins was tested. The samples were exposed to UV during 15, 30, and 60 minutes. EPR spectra were measured with microwaves from an X-band (9.3 GHz in the range of microwave power of 2.2–70 mW. The performed EPR examinations indicate that high concentrations (~1021–1022 spin/g of o-semiquinone free radicals with g factors of 2.0039–2.0045 exist in all the tested samples. For nonirradiated samples, free radical concentration was higher in natural melanin than in synthetic melanin. UV irradiation caused the increase of free radical concentrations in synthetic melanin samples and this effect depends on the time of irradiation. The largest free radical formation in the both melanins was obtained for 60 min of UV irradiation. Free radical concentrations after the UV irradiation of melanins during 30 min were lower than during irradiation by 15 min, and probably this effect was the result of recombination of the radiatively formed free radicals. EPR lines of the tested samples broadened with increasing microwave power, so these lines were homogeneously broadened. The two types of melanins differed in the time of spin-lattice relaxation processes. Slower spin-lattice relaxation processes exist in melanin from Sepia officinalis than in synthetic melanin. UV irradiation did not change the time of spin-lattice relaxation processes in the tested melanins. The performed studies confirmed the usefulness of EPR spectroscopy in cosmetology and medicine.

  11. Accelerated dynamic EPR imaging using fast acquisition and compressive recovery

    Science.gov (United States)

    Ahmad, Rizwan; Samouilov, Alexandre; Zweier, Jay L.

    2016-12-01

    Electron paramagnetic resonance (EPR) allows quantitative imaging of tissue redox status, which provides important information about ischemic syndromes, cancer and other pathologies. For continuous wave EPR imaging, however, poor signal-to-noise ratio and low acquisition efficiency limit its ability to image dynamic processes in vivo including tissue redox, where conditions can change rapidly. Here, we present a data acquisition and processing framework that couples fast acquisition with compressive sensing-inspired image recovery to enable EPR-based redox imaging with high spatial and temporal resolutions. The fast acquisition (FA) allows collecting more, albeit noisier, projections in a given scan time. The composite regularization based processing method, called spatio-temporal adaptive recovery (STAR), not only exploits sparsity in multiple representations of the spatio-temporal image but also adaptively adjusts the regularization strength for each representation based on its inherent level of the sparsity. As a result, STAR adjusts to the disparity in the level of sparsity across multiple representations, without introducing any tuning parameter. Our simulation and phantom imaging studies indicate that a combination of fast acquisition and STAR (FASTAR) enables high-fidelity recovery of volumetric image series, with each volumetric image employing less than 10 s of scan. In addition to image fidelity, the time constants derived from FASTAR also match closely to the ground truth even when a small number of projections are used for recovery. This development will enhance the capability of EPR to study fast dynamic processes that cannot be investigated using existing EPR imaging techniques.

  12. ER=EPR, GHZ, and the Consistency of Quantum Measurements

    CERN Document Server

    Susskind, Leonard

    2014-01-01

    This paper illustrates various aspects of the ER=EPR conjecture.It begins with a brief heuristic argument, using the Ryu-Takayanagi correspondence, for why entanglement between black holes implies the existence of Einstein-Rosen bridges. The main part of the paper addresses a fundamental question: Is ER=EPR consistent with the standard postulates of quantum mechanics? Naively it seems to lead to an inconsistency between observations made on entangled systems by different observers. The resolution of the paradox lies in the properties of multiple black holes, entangled in the Greenberger-Horne-Zeilinger pattern. The last part of the paper is about entanglement as a resource for quantum communication. ER=EPR provides a way to visualize protocols like quantum teleportation. In some sense teleportation takes place through the wormhole, but as usual, classical communication is necessary to complete the protocol.

  13. ER=EPR, GHZ, and the consistency of quantum measurements

    Energy Technology Data Exchange (ETDEWEB)

    Susskind, Leonard [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University, Stanford, CA (United States)

    2016-01-15

    This paper illustrates various aspects of the ER=EPR conjecture. It begins with a brief heuristic argument, using the Ryu-Takayanagi correspondence, for why entanglement between black holes implies the existence of Einstein-Rosen bridges. The main part of the paper addresses a fundamental question: Is ER=EPR consistent with the standard postulates of quantum mechanics? Naively it seems to lead to an inconsistency between observations made on entangled systems by different observers. The resolution of the paradox lies in the properties of multiple black holes, entangled in the Greenberger-Horne-Zeilinger pattern. The last part of the paper is about entanglement as a resource for quantum communication. ER=EPR provides a way to visualize protocols like quantum teleportation. In some sense teleportation takes place through the wormhole, but as usual, classical communication is necessary to complete the protocol. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Radiation fields, dosimetry, biokinetics and biophysical models for cancer induction by ionising radiation 1996 - 1999. Mid-term reports for the period 1996-1997

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, P.; Paretzke, H.G.; Roth, P. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Inst. fuer Strahlenschutz; Michael, B.D. [Mount Vernon Hospital, Northwood (United Kingdom). Gray Lab.; O`Sullivan, D. [Dublin Inst. for Advanced Studies (Ireland)

    1998-12-31

    The main objectives of the first dosimetry project are the measurement of neutron and charged particle flux and energy spectra at altitudes in civil aviation, the determination of response characteristics for detectors, the investigation of calibration procedures, and the evaluation of exposures of aircrews. The overall objective of the second dosimetry project is to improve estimates of dose following the intake of radionuclides by adults and children. The work includes the development of biokinetic and dosimetric models, including models of the gastrointestinal tract, for the systemic behaviour of radionuclides, and for the developing embryo and foetus. Further subjects are target cell dosimetry for short-range particles and the development of computational tools for sensitivity and uncertainty analysis models. The third dosimetry project encompasses the study of different methods for retrospective dose assessments for individuals or groups of individuals accidentally exposed to increased levels of radiation. The methods investigated include electron paramagnetic resonance (EPR) of tooth enamel and chromosome painting (FISH) for lymphocytes in peripheral blood for individual retrospective dose assessments, luminescence techniques on materials in inhabited environment (ceramics, bricks) and model calculations using environmental data as input. (orig.)

  15. Formats

    Directory of Open Access Journals (Sweden)

    Gehmann, Ulrich

    2012-03-01

    Full Text Available In the following, a new conceptual framework for investigating nowadays’ “technical” phenomena shall be introduced, that of formats. The thesis is that processes of formatting account for our recent conditions of life, and will do so in the very next future. It are processes whose foundations have been laid in modernity and which will further unfold for the time being. These processes are embedded in the format of the value chain, a circumstance making them resilient to change. In addition, they are resilient in themselves since forming interconnected systems of reciprocal causal circuits.Which leads to an overall situation that our entire “Lebenswelt” became formatted to an extent we don’t fully realize, even influencing our very percep-tion of it.

  16. Development of radiation biological dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Chul Koo; Kim, Tae Hwan; Lee, Yun Sil; Son, Young Sook; Kim, Soo Kwan; Jang, Won Suk; Le, Sun Joo; Jee, Young Heun; Jung, Woo Jung

    1999-04-01

    Up until now, only a few methods have been developed for radiation biological dosimetry such as conventional chromosome aberration and micronucleus in peripheral blood cell. However, because these methods not only can be estimated by the expert, but also have a little limitation due to need high technique and many times in the case of radiation accident, it is very difficult to evaluate the absorbed dose of victims. Therefore, we should develop effective, easy, simple and rapid biodosimetry and its guideline (triage) to be able to be treated the victims as fast as possible. We established the premature chromosome condensation assay and apoptotic fragment assay which was the significant relationship between dose and cell damages to evaluate the irradiation dose as correct and rapid as possible using lymphocytes and crypt cells, and compared with conventional chromosome aberration assay and micronuclei assay.

  17. Advanced materials in radiation dosimetry

    CERN Document Server

    Bruzzi, M; Nava, F; Pini, S; Russo, S

    2002-01-01

    High band-gap semiconductor materials can represent good alternatives to silicon in relative dosimetry. Schottky diodes made with epitaxial n-type 4 H SiC and Chemical Vapor Deposited diamond films with ohmic contacts have been exposed to a sup 6 sup 0 Co gamma-source, 20 MeV electrons and 6 MV X photons from a linear accelerator to test the current response in on-line configuration in the dose range 0.1-10 Gy. The released charge as a function of the dose and the radiation-induced current as a function of the dose-rate are found to be linear. No priming effects have been observed using epitaxial SiC, due to the low density of lattice defects present in this material.

  18. Free radicals and antioxidants at a glance using EPR spectroscopy.

    Science.gov (United States)

    Spasojević, Ivan

    2011-01-01

    The delicate balance between the advantageous and detrimental effects of free radicals is one of the important aspects of human (patho)physiology. The controlled production of reactive oxygen and nitrogen species has an essential role in the regulation of various signaling switches. On the other hand, imbalanced generation of radicals is highly correlated with the pathogenesis of many diseases which require the application of selected antioxidants to regain the homeostasis. In the era of growing interest for redox processes, electron paramagnetic resonance (EPR) spectroscopy is arguably the best-suited technique for such research due to its ability to provide a unique insight into the world of free radicals and antioxidants. Herein, I present the principles of EPR spectroscopy and the applications of this method in assessing: (i) the oxidative status of biological systems, using endogenous long-lived free radicals (ascorbyl radical (Asc(•)), tocopheroxyl radical (TO(•)), melanin) as markers; (ii) the production of short-lived radicals (hydroxyl radical (OH(•)), superoxide radical anion (O(2)(•-)), sulfur- and carbon-centered radicals), which are implicated in both, oxidative stress and redox signaling; (iii) the metabolism of nitric oxide (NO(•)); (iv) the antioxidative properties of various drugs, compounds, and natural products; (v) other redox-relevant parameter. Besides giving a comprehensive survey of up-to-date literature, I also provide illustrative examples in sufficient detail to provide a means to exploit the potential of EPR in biochemical/physiological/medical research. The emphasis is on the features and characteristics (both positive and negative) relevant for EPR application in clinical sciences. My aim is to encourage fellow colleagues interested in free radicals and antioxidants to expand their base knowledge or methods used in their laboratories with data acquired by EPR or some of the EPR techniques outlined in this review, in order to

  19. The inner containment of an EPR trademark pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ostermann, Dirk; Krumb, Christian; Wienand, Burkhard [AREVA GmbH, Offenbach (Germany)

    2014-08-15

    On February 12, 2014 the containment pressure and subsequent leak tightness tests on the containment of the Finnish Olkiluoto 3 EPR trademark reactor building were completed successfully. The containment of an EPR trademark pressurized water reactor consists of an outer containment to protect the reactor building against external hazards (such as airplane crash) and of an inner containment that is subjected to internal overpressure and high temperature in case of internal accidents. The current paper gives an overview of the containment structure, the design criteria, the validation by analyses and experiments and the containment pressure test.

  20. Resolving the EPR Paradox for the Case of entangled Photons

    CERN Document Server

    Muchowski, Eugen

    2016-01-01

    A system of two polarized photons in singlet state appears as being in one of two product states independent of any measurement. These states depend on the selected polarization angles. With the polarizers on either side perpendicular to each other, both photons pass the polarizers without any disturbance. Action at a distance is therefore not needed to explain the results of the measurements. In general, the elements of physical reality demanded by EPR are the polarization states of the two photons of the entangled pair. As these are local elements in the regions of space of the polarizers the EPR paradox for the case of entangled photons can be regarded as resolved.

  1. Pulsed EPR in the method of spin labels and probes

    Energy Technology Data Exchange (ETDEWEB)

    Dzuba, Sergei A [Institute of Chemical Kinetics and Combustion, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2007-08-31

    Various pulsed EPR in the method of spin labels and probes based on electron spin echo spectroscopy (spin echo envelope modulation through electron-nuclear interactions, electron-electron double resonance, echo detected EPR, etc.) are considered. These methods provide information on the conformations of complex biomolecules, nanostructure of matter, depth of water penetration into biological membranes, supramolecular structure of multicomponent systems (membrane-peptide, etc.), co-operative orientational dynamics of molecules and dynamic low-temperature transitions in disordered molecular media and biosystems.

  2. Pulsed EPR in the method of spin labels and probes

    Science.gov (United States)

    Dzuba, Sergei A.

    2007-08-01

    Various pulsed EPR in the method of spin labels and probes based on electron spin echo spectroscopy (spin echo envelope modulation through electron-nuclear interactions, electron-electron double resonance, echo detected EPR, etc.) are considered. These methods provide information on the conformations of complex biomolecules, nanostructure of matter, depth of water penetration into biological membranes, supramolecular structure of multicomponent systems (membrane-peptide, etc.), co-operative orientational dynamics of molecules and dynamic low-temperature transitions in disordered molecular media and biosystems.

  3. EPR studies of gamma-irradiated taurine single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Bulut, A. E-mail: abulut@samsun.omu.edu.tr; Karabulut, B.; Tapramaz, R.; Koeksal, F

    2000-04-01

    An EPR study of gamma-irradiated taurine [C{sub 2}H{sub 7}NO{sub 3}S] single crystal was carried out at room temperature. The EPR spectra were recorded in the three at mutually perpendicular planes. There are two magnetically distinct sites in monoclinic lattice. The principle values of g and hyperfine constants for both sites were calculated. The results have indicated the presence of {sup 32}SO{sup -}{sub 2} and {sup 33}SO{sup -}{sub 2} radicals. The hyperfine values of {sup 33}SO{sup -}{sub 2} radical were used to obtain O-S-O bond angle for both sites.

  4. Implementing a new EPR lineshape parameter for organic radicals in carbonaceous matter

    OpenAIRE

    Bourbin, Mathilde; Du, Yann Le; Binet, Laurent; Gourier, Didier

    2013-01-01

    Background Electron Paramagnetic Resonance (EPR) is a non-destructive, non-invasive technique useful for the characterization of organic moieties in primitive carbonaceous matter related to the origin of life. The classical EPR parameters are the peak-to-peak amplitude, the linewidth and the g factor; however, such parameters turn out not to suffice to fully determine a single EPR line. Results In this paper, we give the definition and practical implementation of a new EPR parameter based on ...

  5. EPR study of deoxygenated high-temperature superconductors

    Indian Academy of Sciences (India)

    R J Singh; P K Sharma; Shakeel Khan

    2002-05-01

    High-c superconductors are EPR silent but on a little deoxygenation of the high-c materials and their constituents, they yield rich but complex spectra. Spectra of (1) CuO, (2) BaCuO2, (3) CaCuO2, (4) Y2Cu2O5, (5) La2CuO4, (6) La2-CuO4 (M = Sr, Ba), (7) Y based-123, (8) Bi based-2201, 2212, 2223, (9) Tl based-2223 and (10) Hg based-1212,1223 have been studied. One thing common to all these materials is the CuO2 plane which gets fragmented on deoxygenation and the inherent antiferromagnetic coupling is partially destroyed which results in the appearance of the spectra. The spectra recorded have been identified to be due to (1) Cu-monomer, (2) Cu-dimer, (3) Cutetramer, (4) Cu-octamer and (5) one signal at very low field which could not be identified because there was no structure in it and may be due to fragments higher than octamers. Very big fragments do not give any spectra because the original AF order probably remains intact in them. It is expected that when the fragments become magnetically isolated from the bulk, they produce EPR spectra. Most of the spectra have been analyzed and their spin-Hamiltonian parameters determined. The spectra of these species vary a little in terms of g-value and fine-structure splitting constant from sample to sample or even in the same sample and this may be attributed to some extra oxygen attachments retained with these species. Most frequently occurring species is the Cu-tetramer, (CuO)4. As (CuO)4 represents the unit cell of the all important two-dimensional CuO2 plane of the high-c materials, its spectra have been argued to provide some clue to the mechanism of high-c superconductivity. The tetramer (CuO)4 is a four one-half spin system and is essentially 16-fold degenerate by Heisenberg isotropic exchange, it is split into 6 components: one pentet, three triplets and two singlets. In superconductors the pentet appears to be the ground state and in the non-superconducting constituents the singlets seem to form the ground

  6. Scavenging of the one-electron reduction product from nisoldipine with relevant thiols: electrochemical and EPR spectroscopic evidences.

    Science.gov (United States)

    Núñez-Vergara, L J; Díaz-Araya, G; Olea-Azar, C; Atria, A M; Bollo-Dragnic, S; Squella, J A

    1998-11-01

    To determine the formation of the one-electron reduction product from nisoldipine and its reactivity with relevant thiols in mixed medium. Cyclic voltammetry (CV) and electron paramagnetic resonance (EPR) techniques were used to determine the one-electron reduction product corresponding to the nitro radical anion. CV was employed to assess both the rate constants corresponding to the decay of the radicals and its interaction with relevant thiols. The nisoldipine radical anion follows second order kinetics, with an association rate constant of 283+/-16 l mol(-1) sec(-1). Nitro radical anion from nisoldipine significantly reacted with thiol compounds. This reactivity was significantly higher than the natural decay of the radical in mixed medium. EPR spectra recorded in situ using DMF/ 0.1 N NaOH (pH 13) confirmed the formation of the nitro radical anion, giving a well-resolved spectra in 35 lines using 0.1 G modulation. Electrochemical and EPR data indicated that all the tested thiols scavenged the nitro radical anion from nisoldipine. The following tentative order of reactivity towards the thiols can be proposed: cysteamine approximately glutathione > N-acetylcysteine > captopril > penicillamine.

  7. EPR and UV/VIS spectroscopic investigations of VO2+ complexes and compounds formed in alkali pyrosulfates

    DEFF Research Database (Denmark)

    Rasmussen, Søren Birk; Eriksen, Kim Michael; Fehrmann, Rasmus

    2002-01-01

    fraction of the sample occupied by the cation. This indicates that spin-spin relaxation effects are the major contribution to line broadening. Combining information from UV/VIS and EPR spectra shows that the VO2+ unit in the molten salt solvent exhibits electronic properties close to aqueous solutions of V(IV).......The catalytically important molten salt-gas system M2S2O7-M2SO4-V2O5/SO2(g) (M = Na. K, Rb, Cs) has been investigated by X- and Q-band EPR spectroscopy. In order to obtain information about the V(IV) complex formation in the melts, samples rather dilute in V2O5 were quenched from the molten state...

  8. High temperature EPR study of the M3Fe4V6O24 (M = Cu, Zn, Mg and Mn

    Directory of Open Access Journals (Sweden)

    Guskos Niko

    2016-09-01

    Full Text Available Electron paramagnetic resonance (EPR spectra of M3Fe4V6O24 (M = Cu, Zn, Mg and Mn compounds in high temperature range (293 K to 493 K have been investigated. The role of magnetic (Cu, Mn and non-magnetic (Zn, Mg ions in M3Fe4V6O24 structure in formation of magnetic resonance spectra was studied. Temperature dependence of EPR parameters: resonance field, linewidth and integrated intensity were examined. Similarities and differences in temperature behavior of these parameters has been discussed in terms of different relaxation mechanisms and magnetic interactions in the spin systems. An important role of additional magnetic ions (M = Mn or Cu in the M3Fe4V6O24 structure has been identified and its consequences considered.

  9. Effect of UV Irradiation and Temperature on Free Radical Properties in Dehydrocholic and Ursodeoxycholic Acids: An EPR Study

    Directory of Open Access Journals (Sweden)

    Małgorzata Dołowy

    2014-01-01

    Full Text Available The effect of UV irradiation and temperature on the formation and properties of free radicals in two pharmaceutical important bile acids, such as dehydrocholic (DH and ursodeoxycholic acids (UDC, was examined. Electron paramagnetic resonance (EPR spectroscopy was applied to determine the paramagnetic character of UV irradiated and thermally sterilized drugs. Thermal and UV irradiation sterilizations of both compounds were carried out at different conditions according to pharmaceutical norms. The performed EPR measurements of UV irradiated and thermally sterilized DH and UDC samples proved the existence of the complex free radical systems in examined bile acids. Significant influence of UV irradiation in comparison with applied thermal sterilization on free radical concentrations in DH and UDC samples was observed. The results pointed out that thermal method is most suitable for bile acid sterilization. Therefore, this kind of sterilization should be applied in practice.

  10. Radicals as EPR probes of magnetization of gadolinium stearate Langmuir-Blodgett film

    DEFF Research Database (Denmark)

    Koksharov, Y.A.; Bykov, I.V.; Malakho, A.P.;

    2002-01-01

    In the present work we have applied the method of the EPR spin probes which allows performing simultaneously EPR and magnetization measurements to the investigation of magnetism of the Cid stearate Langmuir-Blodgett (LB) films. For this purpose we have prepared and studied by the EPR technique...

  11. Uncertainty in 3D gel dosimetry

    Science.gov (United States)

    De Deene, Yves; Jirasek, Andrew

    2015-01-01

    Three-dimensional (3D) gel dosimetry has a unique role to play in safeguarding conformal radiotherapy treatments as the technique can cover the full treatment chain and provides the radiation oncologist with the integrated dose distribution in 3D. It can also be applied to benchmark new treatment strategies such as image guided and tracking radiotherapy techniques. A major obstacle that has hindered the wider dissemination of gel dosimetry in radiotherapy centres is a lack of confidence in the reliability of the measured dose distribution. Uncertainties in 3D dosimeters are attributed to both dosimeter properties and scanning performance. In polymer gel dosimetry with MRI readout, discrepancies in dose response of large polymer gel dosimeters versus small calibration phantoms have been reported which can lead to significant inaccuracies in the dose maps. The sources of error in polymer gel dosimetry with MRI readout are well understood and it has been demonstrated that with a carefully designed scanning protocol, the overall uncertainty in absolute dose that can currently be obtained falls within 5% on an individual voxel basis, for a minimum voxel size of 5 mm3. However, several research groups have chosen to use polymer gel dosimetry in a relative manner by normalizing the dose distribution towards an internal reference dose within the gel dosimeter phantom. 3D dosimetry with optical scanning has also been mostly applied in a relative way, although in principle absolute calibration is possible. As the optical absorption in 3D dosimeters is less dependent on temperature it can be expected that the achievable accuracy is higher with optical CT. The precision in optical scanning of 3D dosimeters depends to a large extend on the performance of the detector. 3D dosimetry with X-ray CT readout is a low contrast imaging modality for polymer gel dosimetry. Sources of error in x-ray CT polymer gel dosimetry (XCT) are currently under investigation and include inherent

  12. Melt-compounded composites of ethylene vinyl acetate with magnesium sulfate as flexible EPR dosimeters: Mechanical properties, manufacturing process feasibility and dosimetric characteristics.

    Science.gov (United States)

    Suman, S K; Kadam, R M; Mondal, R K; Murali, S; Dubey, K A; Bhardwaj, Y K; Natarajan, V

    2017-03-01

    Novel polymeric composites for radiation dosimetry were developed. The composites were prepared by solvent-free melt compounding of ethylene vinyl acetate (EVA) (40% vinyl) and magnesium sulfate (MgSO4). Mechanical properties, melt flow characteristics and dosimetric properties were investigated. The composites with up to 50% (wt) of MgSO4 were flexible and capable of flow. The dose response of the EPR signal of the composites was studied in the dose range 3Gy-4kGy and found to be linear between 18Gy and 4kGy. The reproducibility of dose measurements was good. The signal fading rate and the energy dependence of the dose response were found to be acceptable.

  13. Non-local common cause explanations for EPR

    CERN Document Server

    Egg, Matthias

    2013-01-01

    The paper argues that a causal explanation of the correlated outcomes of EPR-type experiments is desirable and possible. It shows how Bohmian mechanics and the GRW mass density theory offer such an explanation in terms of a non-local common cause.

  14. Accurate Extraction of Nanometer Distances in Multimers by Pulse EPR

    Science.gov (United States)

    Valera, Silvia; Ackermann, Katrin; Pliotas, Christos; Huang, Hexian; Naismith, James H.

    2016-01-01

    Abstract Pulse electron paramagnetic resonance (EPR) is gaining increasing importance in structural biology. The PELDOR (pulsed electron–electron double resonance) method allows extracting distance information on the nanometer scale. Here, we demonstrate the efficient extraction of distances from multimeric systems such as membrane‐embedded ion channels where data analysis is commonly hindered by multi‐spin effects. PMID:26865468

  15. On the Measurement Problem and the EPR Paradox

    OpenAIRE

    Muchowski, Eugen

    2016-01-01

    After a polarization measurement with photons in singlet state we know for certain the photons were in the measured state prior to measurement. Photons in singlet state do therefore not exhibit action at a distance. The EPR paradox with entangled photons has been challenged. It was also shown why quantum mechanics infringes Bells inequality.

  16. Security of EPR-based Quantum Key Distribution

    CERN Document Server

    Inamori, H

    2000-01-01

    We propose a proof of the security of EPR-based quantum key distribution against enemies with unlimited computational power. The proof holds for a protocol using interactive error-reconciliation scheme. We assume in this paper that the legitimate parties receive a given number of single photon signals and that their measurement devices are perfect.

  17. In aqua vivo EPID dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Wendling, Markus; McDermott, Leah N.; Mans, Anton; Olaciregui-Ruiz, Igor; Pecharroman-Gallego, Raul; Sonke, Jan-Jakob; Stroom, Joep; Herk, Marcel J.; Mijnheer, Ben van [Department of Radiation Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands)

    2012-01-15

    Purpose: At the Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital in vivo dosimetry using an electronic portal imaging device (EPID) has been implemented for almost all high-energy photon treatments of cancer with curative intent. Lung cancer treatments were initially excluded, because the original back-projection dose-reconstruction algorithm uses water-based scatter-correction kernels and therefore does not account for tissue inhomogeneities accurately. The aim of this study was to test a new method, in aqua vivo EPID dosimetry, for fast dose verification of lung cancer irradiations during actual patient treatment. Methods: The key feature of our method is the dose reconstruction in the patient from EPID images, obtained during the actual treatment, whereby the images have been converted to a situation as if the patient consisted entirely of water; hence, the method is termed in aqua vivo. This is done by multiplying the measured in vivo EPID image with the ratio of two digitally reconstructed transmission images for the unit-density and inhomogeneous tissue situation. For dose verification, a comparison is made with the calculated dose distribution with the inhomogeneity correction switched off. IMRT treatment verification is performed for each beam in 2D using a 2D {gamma} evaluation, while for the verification of volumetric-modulated arc therapy (VMAT) treatments in 3D a 3D {gamma} evaluation is applied using the same parameters (3%, 3 mm). The method was tested using two inhomogeneous phantoms simulating a tumor in lung and measuring its sensitivity for patient positioning errors. Subsequently five IMRT and five VMAT clinical lung cancer treatments were investigated, using both the conventional back-projection algorithm and the in aqua vivo method. The verification results of the in aqua vivo method were statistically analyzed for 751 lung cancer patients treated with IMRT and 50 lung cancer patients treated with VMAT. Results: The improvements by

  18. Technical Basis Document for PFP Area Monitoring Dosimetry Program

    CERN Document Server

    Cooper, J R

    2000-01-01

    This document describes the phantom dosimetry used for the PFP Area Monitoring program and establishes the basis for the Plutonium Finishing Plant's (PFP) area monitoring dosimetry program in accordance with the following requirements: Title 10, Code of Federal Regulations (CFR), part 835, ''Occupational Radiation Protection'' Part 835.403; Hanford Site Radiological Control Manual (HSRCM-1), Part 514; HNF-PRO-382, Area Dosimetry Program; and PNL-MA-842, Hanford External Dosimetry Technical Basis Manual.

  19. Dosimetry at a 400 keV accelerator

    DEFF Research Database (Denmark)

    Miller, A.

    1992-01-01

    Absolute calorimetric dosimetry and relative dose mapping methods are described for a 400 keV electron accelerator used for polymer curing and crosslinking experiments. These methods of dosimetry are also useful at accelerators used in gas cleaning processes.......Absolute calorimetric dosimetry and relative dose mapping methods are described for a 400 keV electron accelerator used for polymer curing and crosslinking experiments. These methods of dosimetry are also useful at accelerators used in gas cleaning processes....

  20. Personnel neutron dosimetry at Department of Energy facilities

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-08-01

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

  1. Effect of thermal treatment on potato starch evidenced by EPR, XRD and molecular weight distribution.

    Science.gov (United States)

    Bidzińska, Ewa; Michalec, Marek; Pawcenis, Dominika

    2015-12-01

    Effect of heating of the potato starch on damages of its structure was investigated by quantitative electron paramagnetic resonance (EPR) spectroscopy, X-ray diffraction and determination of the molecular weight distribution. The measurements were performed in the temperature range commonly used for starch modifications optimizing properties important for industrial applications. Upon thermal treatment, because of breaking of the polymer chains, diminishing of the average molecular weights occurred, which significantly influences generation of radicals, evidenced by EPR. For the relatively mild conditions, with heating parameters not exceeding temperature 230 °C and time of heating equal to 30 min a moderate changes of both the number of thermally generated radicals and the mean molecular weight of the starch were observed. After more drastic thermal treatment (e.g. 2 h at 230 °C), a rapid increase in the radical amount occurred, which was accompanied by significant reduction of the starch molecular size and crystallinity. Experimentally established threshold values of heating parameters should not be exceeded in order to avoid excessive damages of the starch structure accompanied by the formation of the redundant amount of radicals. This requirement is important for industrial applications, because significant destruction of the starch matrix might annihilate the positive influence of the previously performed intentional starch modification.

  2. Synthesis, XRD, TEM, EPR, and Optical Absorption Spectral Studies of CuZnO2 Nanocompound

    Directory of Open Access Journals (Sweden)

    T. Ravindra Reddy

    2014-01-01

    Full Text Available Synthesis of nano CuZnO2 compound is carried out by thermal decomposition method. The crystalline phase of the material is characterized by XRD. The calculated unit cell constants are a=3.1 Å and c=3.4786 Å and are of tetragonal structure. The unit cell constants are different from wurtzite (hexagonal which indicate that a nanocompound is formed. Further TEM images reveal that the metal ion is in tetragonal structure with oxygen ligands. The prepared CuZnO2 is then characterized for crystallite size analysis by employing transmission electron microscopy (TEM. The size is found to be 100 nm. Uniform bright rings are noticed in the TEM picture suggesting that the nanocrystals have preferential instead of random orientations. The selected-area electron diffraction (SAED pattern clearly indicates the formation of CuO-ZnO nanocompound. The nature of bonding is studied by electron paramagnetic resonance (EPR. The covalency character is about 0.74 and thus the compound is electrically less conductive. Optical absorption spectral studies suggest that Cu(II is placed in tetragonal elongation crystal field. The spin-orbit coupling constant, λ, is calculated using the EPR and optical absorption spectral results suggest some covalent bond between metal and ligand. Near infrared (NIR spectra are due to hydroxyl and water fundamentals.

  3. Electrochemical and EPR characterization of 1,4-dihydropyridines. Reactivity towards alkyl radicals.

    Science.gov (United States)

    Núñez-Vergara, Luis J; López-Alarcón, C; Navarrete-Encina, P A; Atria, A M; Camargo, C; Squella, J A

    2003-01-01

    This work reports the electrochemical oxidation of a series of three synthesized 4-substituted-1,4-dihydropyridine derivatives in different electrolytic media. Also, an EPR characterization of intermediates and the reactivity of derivatives towards ABAP-derived alkyl radicals are reported. Dynamic, differential pulse and cyclic voltammetry studies on a glassy carbon electrode showed an irreversible single-peak due to the oxidation of the 1,4-dihydropyridine (1,4-DHP) ring via 2-electrons to the corresponding pyridine derivative. Levich plots were linear in different media, indicating that the oxidation process is diffusion-controlled. Calculated diffusion coefficients did not exhibit significant differences between the derivatives in the same medium. The oxidation mechanism follows the general pathway (electron, H+, electron, H+) with formation of an unstable pyridinium radical. One-electron oxidation intermediate was confirmed with controlled potential electrolysis (CPE) and EPR experiments. On applying N-tert-butyl-alpha-phenylnitrone (PBN) and 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as the spin trap, these unstable radical intermediates from the oxidation of 1,4-DHP derivatives were intercepted. The final product of the CPE, i.e. pyridine derivative, was identified by GC-MS technique. Direct reactivity of the synthesized compounds towards alkyl radicals was demonstrated by UV-Vis. spectroscopy and GC-MS technique. Results indicate that these derivatives significantly react with the radicals, even compared with a well-known antioxidant drug such as nisoldipine.

  4. Multifrequency EPR study on freeze-dried fruits before and after X-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yordanov, N.D. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)]. E-mail: ndyepr@bas.bg; Aleksieva, K. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Dimitrova, A. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Georgieva, L. [Institute of Cryobiology and Food Technologies, 1162 Sofia (Bulgaria); Tzvetkova, E. [Institute of Cryobiology and Food Technologies, 1162 Sofia (Bulgaria)

    2006-09-15

    X-, K- and Q-band EPR studies on lyophilized whole pulp parts of blue plum, apricot, peach, melon as well as achens and pulp separately of strawberry before and after X-ray irradiation are reported. Before irradiation all samples show in X band a weak singlet EPR line with g=2.0030+/-0.0005, except melon, which is EPR silent. Immediately after irradiation all samples exhibit complex fruit-depending spectra, which decay with time and change to give, in ca. 50days, an asymmetric singlet EPR line with g=2.0041+/-0.0005. Only apricot pulp gave a typical ''sugar-like'' EPR spectrum. Singlet EPR lines recorded after irradiation in X -band are K- and Q-band resolved as typical anisotropic EPR spectra with g{sub ||}=2.0023+/-0.0003 and g{sub -}bar =2.0041+/-0.0005. In addition, K- and Q-band EPR spectra of all samples show a superposition with the six EPR lines of Mn{sup 2+} naturally present in the fruits. The saturation behavior of the EPR spectra of achens of lyophilized and fresh strawberry is also studied. The differences in g factors of samples before and after X-ray irradiation might be used for the identification of radiation processing of fruits in the case of pulp and the differences in the EPR saturation behavior might be used for the achens of strawberry.

  5. Advances in nuclear particle dosimetry for radiation protection and medicine - Ninth Symposium on Neutron Dosimetry (Editorial Material, English)

    Energy Technology Data Exchange (ETDEWEB)

    Zoetelief, J; Bos, A J.; Schuhmacher, H; McDonald, Joseph C.; Schultz, F W.; Pihet, P

    2004-12-15

    The Ninth Symposium on Neutron Dosimetry has been expanded to cover not only neutron radiation but heavy charged particle dosimetry as well. The applications are found in such fields as radiation protection, aircrew dosimetry, medicine, nuclear power and accelerator health physics. Scientists from many countries from around the world presented their work, and described the latest developments in techniques and instrumentation.

  6. EPR and UV/VIS spectroscopic investigations of VO2+ complexes and compounds formed in alkali pyrosulfates

    DEFF Research Database (Denmark)

    Rasmussen, Søren Birk; Eriksen, Kim Michael; Fehrmann, Rasmus

    2002-01-01

    The catalytically important molten salt-gas system M2S2O7-M2SO4-V2O5/SO2(g) (M = Na. K, Rb, Cs) has been investigated by X- and Q-band EPR spectroscopy. In order to obtain information about the V(IV) complex formation in the melts, samples rather dilute in V2O5 were quenched from the molten state...... at 450-460degreesC to 0degreesC. EPR spectra of the quenched samples were recorded on samples with alkali to vanadium (M/V) ratios 40, 80 and 160. The spectra show that two V(IV) complexes dominate in the melt regardless of the type of alkali metal ion. In systems with low activity of sulfate...... a paramagnetic V(IV) complex with g(parallel to) = 1.915, g(perpendicular to) = 1,978 and line widths 5-15 Gauss is observed. In systems saturated with M2SO4 the obtained EPR spectra show a paramagnetic complex with the g-tensors g(parallel to) = 1.930, g(perpendicular to) = 1.980 and line widths 20-60 Gauss...

  7. Verification of dosimetry planning in brachytherapy in format Dicom and EUD calculation of Risk in bodies; Verificacion de la planificacion dosimetria en braquiterapia en formato Dicom y calculo del EUD en organos de riesgo

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Hernandez, M. J.; Sendon del Rio, J. R.; Ayala Lazaro, R.; Jimenez Rojas, M. R.; Gomez Cores, S.; Polo Cezon, R.; Lopez Bote, M. A.

    2013-07-01

    This work Describes a program that automates the verification of the schedules in brachytherapy (configuration and dosimetric treatment parameters) for sources of Ir-192 (mHDR v2) and Co-60 (Co0.A86) from the plan exported in DICOM format data. (Author)

  8. Instrumentation for the individual dosimetry of workers

    CERN Document Server

    Thévenin, J C

    2003-01-01

    The control of the radiation dose exposure of workers and personnel exposed to ionizing radiations (nuclear industry, nuclear medicine, army, university laboratories etc..) is ensured by individual dosemeters. This dosimetry is mandatory for all workers susceptible to be exposed to more than 30% of the regulatory dose limit. dosemeters are worn on the chest and in some particular cases, on the finger (dosemeter rings) or on the wrist. Passive dosemeters allow to measure the dose a posteriori, while electronic dosemeters allow a direct reading and recording of the dose. This article presents successively: 1 - the general principles of individual dosimetry: situations of exposure, radiation detection, operational data, standardization, calibration and quality assurance, measurement uncertainties; 2 - goals and regulatory framework of individual dosimetry: regulation and recommendations, optimization, respect of dose limits, accidental situations; 3 - passive dosemeters: film, thermoluminescent, radio-photolumin...

  9. Model selection for radiochromic film dosimetry

    CERN Document Server

    Méndez, Ignasi

    2015-01-01

    The purpose of this study was to find the most accurate model for radiochromic film dosimetry by comparing different channel independent perturbation models. A model selection approach based on (algorithmic) information theory was followed, and the results were validated using gamma-index analysis on a set of benchmark test cases. Several questions were addressed: (a) whether incorporating the information of the non-irradiated film, by scanning prior to irradiation, improves the results; (b) whether lateral corrections are necessary when using multichannel models; (c) whether multichannel dosimetry produces better results than single-channel dosimetry; (d) which multichannel perturbation model provides more accurate film doses. It was found that scanning prior to irradiation and applying lateral corrections improved the accuracy of the results. For some perturbation models, increasing the number of color channels did not result in more accurate film doses. Employing Truncated Normal perturbations was found to...

  10. Performance testing of UK personal dosimetry laboratories

    CERN Document Server

    Marshall, T O

    1985-01-01

    The proposed Ionising Radiations Regulations will require all UK personal dosimetry laboratories that monitor classified personnel to be approved for personal dosimetry by the Health and Safety Executive. It is suggested that these approvals should be based on general and supplementary criteria published by the British Calibration Service (BCS) for laboratory approval for the provision of personal dosimetry services. These criteria specify certain qualitative requirements and also indicate the need for regular tests of performance to be carried out to ensure constancy of dosimetric standards. This report concerns the latter. The status of the BCS criteria is discussed and the need for additional documents to cover new techniques and some modifications to existing documents is indicated. A means is described by which the technical performance of laboratories, concerned with personal monitoring for external radiations, can be assessed, both initially and ongoing. The costs to establish the scheme and operate it...

  11. Bayesian Methods for Radiation Detection and Dosimetry

    CERN Document Server

    Groer, Peter G

    2002-01-01

    We performed work in three areas: radiation detection, external and internal radiation dosimetry. In radiation detection we developed Bayesian techniques to estimate the net activity of high and low activity radioactive samples. These techniques have the advantage that the remaining uncertainty about the net activity is described by probability densities. Graphs of the densities show the uncertainty in pictorial form. Figure 1 below demonstrates this point. We applied stochastic processes for a method to obtain Bayesian estimates of 222Rn-daughter products from observed counting rates. In external radiation dosimetry we studied and developed Bayesian methods to estimate radiation doses to an individual with radiation induced chromosome aberrations. We analyzed chromosome aberrations after exposure to gammas and neutrons and developed a method for dose-estimation after criticality accidents. The research in internal radiation dosimetry focused on parameter estimation for compartmental models from observed comp...

  12. Dosimetry procedures for an industrial irradiation plant

    Science.gov (United States)

    Grahn, Ch.

    Accurate and reliable dosimetry procedures constitute a very important part of process control and quality assurance at a radiation processing plant. γ-Dose measurements were made on the GBS 84 irradiator for food and other products on pallets or in containers. Chemical dosimeters wre exposed in the facility under conditions of the typical plant operation. The choice of the dosimeter systems employed was based on the experience in chemical dosimetry gained over several years. Dose uniformity information was obtained in air, spices, bulbs, feeds, cosmetics, plastics and surgical goods. Most products currently irradiated require dose uniformity which can be efficiently provided by pallet or box irradiators like GBS 84. The radiation performance characteristics and some dosimetry procedures are discussed.

  13. Growth history of hydrothermal chimneys at EPR 9―10°N: A structural and mineralogical study

    Institute of Scientific and Technical Information of China (English)

    PENG Xiaotong; ZHOU Huaiyang

    2005-01-01

    Based on structural and mineralogical characteristics of four hydrothermal chimney samples collected by submersible Alvin, growth history and formation environment of hydrothermal chimney at EPR 9―10°N are established. It is shown that there occur two types of hydrothermal chimney with different deposition environments at EPR 9―10°N according to differences in their shape, structure and mineral assemblage: type I chimney forms in an environment with high temperature, low pH and strong reducing hydrothermal focus flow and type II chimney forms in a relatively low temperature, high pH and rich Zn hydrothermal environment. Growth of type I chimney begins with the formation of anhydrite. Subsequently deposition of Cu-Fe-Zn sulphide in various directions of chimneys decides the final structure of this type of chimney. According to observation and analysis of mineral assemblages, the formation process of type I chimney could be divided into three stages from early, middle to late. Changes of temperature and major chemical reaction type in the process of hydrothermal chimney formation are also deduced. Different from type I chimney, quenching crystalline of pyrite and/or crystalline of sphalerite provide the growth foundation of type II chimney in the early stage of chimney formation.

  14. Reactor Dosimetry State of the Art 2008

    Science.gov (United States)

    Voorbraak, Wim; Debarberis, Luigi; D'Hondt, Pierre; Wagemans, Jan

    2009-08-01

    Oral session 1: Retrospective dosimetry. Retrospective dosimetry of VVER 440 reactor pressure vessel at the 3rd unit of Dukovany NPP / M. Marek ... [et al.]. Retrospective dosimetry study at the RPV of NPP Greifswald unit 1 / J. Konheiser ... [et al.]. Test of prototype detector for retrospective neutron dosimetry of reactor internals and vessel / K. Hayashi ... [et al.]. Neutron doses to the concrete vessel and tendons of a magnox reactor using retrospective dosimetry / D. A. Allen ... [et al.]. A retrospective dosimetry feasibility study for Atucha I / J. Wagemans ... [et al.]. Retrospective reactor dosimetry with zirconium alloy samples in a PWR / L. R. Greenwood and J. P. Foster -- Oral session 2: Experimental techniques. Characterizing the Time-dependent components of reactor n/y environments / P. J. Griffin, S. M. Luker and A. J. Suo-Anttila. Measurements of the recoil-ion response of silicon carbide detectors to fast neutrons / F. H. Ruddy, J. G. Seidel and F. Franceschini. Measurement of the neutron spectrum of the HB-4 cold source at the high flux isotope reactor at Oak Ridge National Laboratory / J. L. Robertson and E. B. Iverson. Feasibility of cavity ring-down laser spectroscopy for dose rate monitoring on nuclear reactor / H. Tomita ... [et al.]. Measuring transistor damage factors in a non-stable defect environment / D. B. King ... [et al.]. Neutron-detection based monitoring of void effects in boiling water reactors / J. Loberg ... [et al.] -- Poster session 1: Power reactor surveillance, retrospective dosimetry, benchmarks and inter-comparisons, adjustment methods, experimental techniques, transport calculations. Improved diagnostics for analysis of a reactor pulse radiation environment / S. M. Luker ... [et al.]. Simulation of the response of silicon carbide fast neutron detectors / F. Franceschini, F. H. Ruddy and B. Petrović. NSV A-3: a computer code for least-squares adjustment of neutron spectra and measured dosimeter responses / J. G

  15. A mathematical approach to optimal selection of dose values in the additive dose method of ERP dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, R.B.; Haskell, E.H.; Kenner, G.H. [Utah Univ., Salt Lake City, UT (United States)

    1996-01-01

    Additive dose methods commonly used in electron paramagnetic resonance (EPR) dosimetry are time consuming and labor intensive. We have developed a mathematical approach for determining optimal spacing of applied doses and the number of spectra which should be taken at each dose level. Expected uncertainitites in the data points are assumed to be normally distributed with a fixed standard deviation and linearity of dose response is also assumed. The optimum spacing and number of points necessary for the minimal error can be estimated, as can the likely error in the resulting estimate. When low doses are being estimated for tooth enamel samples the optimal spacing is shown to be a concentration of points near the zero dose value with fewer spectra taken at a single high dose value within the range of known linearity. Optimization of the analytical process results in increased accuracy and sample throughput.

  16. Dosimetry of Low-Energy Beta Radiation

    DEFF Research Database (Denmark)

    Borg, Jette

    Useful techniques and procedures for derermination of absorbed doses from exposure in a low-energy beta radiation were studied and evaluated. The four techniques included were beta spectrometry, extrapolation chamber dosimetry, Monte Carlo (MC) calculations, and exoelectron dosimetry. As a typical...... low-energy beta radiation field a moderated spectrum from a carbon-14 source was used. The measured responce of a Si(Li) detector to photons (bremsstrahlung) showed fine agreemant with the MC calculated photon response, whereas the difference between measured and MC calculated response to electrons...

  17. Technical basis for internal dosimetry at Hanford

    Energy Technology Data Exchange (ETDEWEB)

    Sula, M.J.; Carbaugh, E.H.; Bihl, D.E.

    1991-07-01

    The Hanford Internal Dosimetry Program, administered by Pacific Northwest Laboratory for the US Department of Energy, provides routine bioassay monitoring for employees who are potentially exposed to radionuclides in the workplace. This report presents the technical basis for routine bioassay monitoring and the assessment of internal dose at Hanford. The radionuclides of concern include tritium, corrosion products ({sup 58}Co, {sup 60}Co, {sup 54}Mn, and {sup 59}Fe), strontium, cesium, iodine, europium, uranium, plutonium, and americium,. Sections on each of these radionuclides discuss the sources and characteristics; dosimetry; bioassay measurements and monitoring; dose measurement, assessment, and mitigation and bioassay follow-up treatment. 78 refs., 35 figs., 115 tabs.

  18. Technical basis for internal dosimetry at Hanford

    Energy Technology Data Exchange (ETDEWEB)

    Sula, M.J.; Carbaugh, E.H.; Bihl, D.E.

    1989-04-01

    The Hanford Internal Dosimetry Program, administered by Pacific Northwest Laboratory for the US Department of Energy, provides routine bioassay monitoring for employees who are potentially exposed to radionuclides in the workplace. This report presents the technical basis for routine bioassay monitoring and the assessment of internal dose at Hanford. The radionuclides of concern include tritium, corrosion products (/sup 58/Co, /sup 60/Co, /sup 54/Mn, and /sup 59/Fe), strontium, cesium, iodine, europium, uranium, plutonium, and americium. Sections on each of these radionuclides discuss the sources and characteristics; dosimetry; bioassay measurements and monitoring; dose measurement, assessment, and mitigation; and bioassay follow-up treatment. 64 refs., 42 figs., 118 tabs.

  19. Optically stimulated luminescence in retrospective dosimetry

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Murray, A.S.

    2002-01-01

    Since the beginning of the 1990s the exploration of optically stimulated luminescence (OSL) in retrospective accident dosimetry has driven an intensive investigation and development programme at Riso into measurement facilities and techniques. This paper reviews some of the outcomes of this progr......Since the beginning of the 1990s the exploration of optically stimulated luminescence (OSL) in retrospective accident dosimetry has driven an intensive investigation and development programme at Riso into measurement facilities and techniques. This paper reviews some of the outcomes...

  20. SNL RML recommended dosimetry cross section compendium

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, P.J.; Kelly, J.G.; Luera, T.F. [Sandia National Labs., Albuquerque, NM (United States); VanDenburg, J. [Science and Engineering Associates, Inc., Albuquerque, NM (United States)

    1993-11-01

    A compendium of dosimetry cross sections is presented for use in the characterization of fission reactor spectrum and fluence. The contents of this cross section library are based upon the ENDF/B-VI and IRDF-90 cross section libraries and are recommended as a replacement for the DOSCROS84 multigroup library that is widely used by the dosimetry community. Documentation is provided on the rationale for the choice of the cross sections selected for inclusion in this library and on the uncertainty and variation in cross sections presented by state-of-the-art evaluations.

  1. Dosimetry of Low-Energy Beta Radiation

    DEFF Research Database (Denmark)

    Borg, Jette

    Useful techniques and procedures for derermination of absorbed doses from exposure in a low-energy beta radiation were studied and evaluated. The four techniques included were beta spectrometry, extrapolation chamber dosimetry, Monte Carlo (MC) calculations, and exoelectron dosimetry. As a typical...... low-energy beta radiation field a moderated spectrum from a carbon-14 source was used. The measured responce of a Si(Li) detector to photons (bremsstrahlung) showed fine agreemant with the MC calculated photon response, whereas the difference between measured and MC calculated response to electrons...

  2. Thermoluminescent dosimetry in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lara C, A.; Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Legaria, Av. Legaria 694, Col. Irrigacion, 11500 Ciudad de Mexico (Mexico); Osorio V, M. [ISSSTE, Centro Medico Nacional 20 de Noviembre, Felix Cuevas 540, Col. del Valle, 03100 Ciudad de Mexico (Mexico); Hernandez O, O., E-mail: armando_lara_cam@yahoo.com.mx [Hospital General de Mexico, Dr. Balmis 148, Col. Doctores, 06726 Ciudad de Mexico (Mexico)

    2016-10-15

    In this work we studied the dosimetry performed on CT scan in two different equipment, SOMATOM and Phillips, with 16 and 64 slice respectively. We used 51 pellets of lithium fluoride doped with magnesium and titanium (LiF: Mg, Ti) also knows as TLD-100 due to its physical properties and its easy of use, in this study, first analysis a batch of 56 pellets, but only 53 pellets were optimal for this study, cesium-137 was used as source irradiation, then proceeded to calibrate the batch with X-rays source, measuring the corresponding dose in a Farmers ionization chamber, then, we obtained a calibration curve, and we used as reference to calculation of the applied dose, finally designing ergonomic mesh, were it was deposited a TLD 100, placed in a regions of interest were made to each scan type. Once characterized our material proceeded to testing in 30 patients, which were irradiated with X-ray tube, whose operation was performed at 80, 120 kV with a current of 100, 300 and 400 m A according to scanning protocol. Overall we measured dose of 5 mGy to 53 mGy, these measurements reflect significant dose to can induced cancer, due previous reports published, that doses greater than 20 mGy there is a risk of developing cancer in the long term, but in practice when it assigned a medical diagnosis, there are no dose limits due to benefits patients, however, IAEA publish recommendations that allow us to carry out optimum handling of ionizing radiation, among these is the quality control of the tomography equipment that helps greatly reduce patient dose. (Author)

  3. Kinetics model for lutate dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Lima, M.F.; Mesquita, C.H., E-mail: mflima@ipen.br, E-mail: chmesqui@ipen.br [Instituto de Pesquisas Energeticas (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-11-01

    The use of compartmental analysis to predict the behavior of drugs in the organism is considered the better option among numerous methods employed in pharmacodynamics. A six compartments model was developed to determinate the kinetic constants of 177Lu-DOTATATO biodistribution using data from one published study with 67 patients treated by PRRT (Peptide receptor radionuclide therapy) and followed by CT during 68,25 hours. The compartmental analysis was made using the software AnaComp Registered-Sign . The influence of the time pos-injection over the dose assessment was studied taking into account the renal excretion management by aminoacid coinfusion, whose direct effects persist in the first day. The biodistribution curve was split in five sectors: 0-0.25h; 0-3.25h; 3.25-24.25h; 24.25-68.25h and 3.25-68.25h. After the examination of that influence, the study was concentrated in separate the biodistribution curve in two phases. Phase 1: governed by uptake from the blood, considering the time pos-injection until 3.25h and phase 2: governed by renal excretion, considering the time pos-injection from 3.25h to 68.25h. The model considered the organs and tissues superposition in the CT image acquisition by sampling parameters as the contribution of the the activity concentration in blood and relation between the sizes of the whole body and measured organs. The kinetic constants obtained from each phase (1 and 2) were used in dose assessment to patients in 26 organs and tissues described by MIRD. Dosimetry results were in agreement with the available results from literature, restrict to whole body, kidneys, bone marrow, spleen and liver. The advantage of the proposed model is the compartmental method quickness and power to estimate dose in organs and tissues, including tumor that, in the most part, were not discriminate by voxels of phantoms built using CT images. (author)

  4. Kinetic measurements using EPR imaging with a modulated field gradient.

    Science.gov (United States)

    Herrling, Thomas; Fuchs, Jürgen; Groth, Norbert

    2002-01-01

    EPR imaging with modulated field gradient was applied for the investigation of fast diffusion processes. Three different imaging methods are possible: spectral-temporal, spatio-temporal, and spectral-spatial imaging. The time resolution is on the order of seconds and the spatial resolution is in the micrometer region. The efficiency of this imaging technique is demonstrated for the penetration of the spin probe Tempol in the skin of hairless mice biopsies. The skin is normally protected against the penetration of water soluble substances by the horny layer, a resistive thin lipophilic layer. Overcoming this horny layer for water soluble ingredients is one of the main practical problems for the topical application of pharmaceutics which could be investigated by EPR imaging. Different images represent the penetration behavior of the water soluble Tempol in the skin after treatment with the penetration enhancer DMSO (Dimethylsulfoxide) and after removing the horny layer.

  5. Kinetic Measurements Using EPR Imaging with a Modulated Field Gradient

    Science.gov (United States)

    Herrling, Thomas; Fuchs, Jürgen; Groth, Norbert

    2002-01-01

    EPR imaging with modulated field gradient was applied for the investigation of fast diffusion processes. Three different imaging methods are possible: spectral-temporal, spatio-temporal, and spectral-spatial imaging. The time resolution is on the order of seconds and the spatial resolution is in the micrometer region. The efficiency of this imaging technique is demonstrated for the penetration of the spin probe Tempol in the skin of hairless mice biopsies. The skin is normally protected against the penetration of water soluble substances by the horny layer, a resistive thin lipophilic layer. Overcoming this horny layer for water soluble ingredients is one of the main practical problems for the topical application of pharmaceutics which could be investigated by EPR imaging. Different images represent the penetration behavior of the water soluble Tempol in the skin after treatment with the penetration enhancer DMSO (Dimethylsulfoxide) and after removing the horny layer.

  6. Structured Reporting Method for ePR Generation

    Directory of Open Access Journals (Sweden)

    Arash Ebrahimi

    2007-08-01

    Full Text Available Appropriate electronic medical report-making soft-wares help physicians to personally generate records for paper printing and ePR access. Flat data-sheets with check-boxes that have been already used in traditional medical paper reports, do not satisfy today's physician demands for more professional reports."nAlternatively, Structured Reporting (SR as the modified version of flat check-box based reporting method is being selected. In this method, items are nested in a hieratical tree so that each reporting item includes several substitutions. Hence, computer generates professional sentences with logical pre-defined combination of selected items. In our work, on the basis of SR method, we provided solution for reporting of Endoscopy procedures that is accepted by several Gastroenterologists as a proper software. In addi-tion, successful results in generation of ePRs using SR are newly achieved in Cardiology.

  7. Belgian primary care EPR: assessment of nationwide routine data extraction.

    Science.gov (United States)

    De Clercq, Etienne; van Casteren, Viviane; Bossuyt, Nathalie; Goderis, Geert; Moreels, Sarah

    2014-01-01

    Starting in 2009, the first ever Belgian nationwide data collection network using routine data extracted from primary care EPR (upload method) has been built from scratch. The network also uses a manual web-based data collection method. This paper compares these two methods by analysing missing and most recent values for certain parameters. We collected data from 4954 practices, pertaining to 29,180 patients. Mean values for the most recent parameters were similar regardless of which data collection method was used. Many missing recent values (>46%) were found for all of the parameters when using the upload method. It seems that, in Belgium, uploading routine data from primary care EPR on a large scale is suitable and allows the collection of chronological retrospective data. However, the method still requires major, carefully controlled improvements.

  8. Total loss of AC power analysis for EPR reactor

    Energy Technology Data Exchange (ETDEWEB)

    Darnowski, Piotr, E-mail: piotr.darnowski@itc.pw.edu.pl [Warsaw University of Technology, Institute of Heat Engineering, Nowowiejska 21/25, 00-665 Warsaw (Poland); Skrzypek, Eleonora, E-mail: eleonora.skrzypek@ncbj.gov.pl [Warsaw University of Technology, Institute of Heat Engineering, Nowowiejska 21/25, 00-665 Warsaw (Poland); National Centre for Nuclear Research (NCBJ), A. Sołtana 7, 05-400 Otwock-Świerk (Poland); Mazgaj, Piotr, E-mail: piotr.mazgaj@itc.pw.edu.pl [Warsaw University of Technology, Institute of Heat Engineering, Nowowiejska 21/25, 00-665 Warsaw (Poland); Świrski, Konrad [Warsaw University of Technology, Institute of Heat Engineering, Nowowiejska 21/25, 00-665 Warsaw (Poland); Gandrille, Pascal [AREVA NP SAS, Tour AREVA, 1 place Jean Millier, 92084 Paris La Défense (France)

    2015-08-15

    Highlights: • Total loss of AC power (Station Blackout) was simulated for the EPR reactor model. • In-vessel phase of the accident is under consideration. • Comparison of MELCOR and MAAP results is presented. • MELCOR and MAAP results are comparable. - Abstract: In this paper the results of severe accident simulations for the EPR reactor in the case of loss of offsite power combined with total failure of all diesel generators (total loss of AC power) are presented. Calculations were performed with MELCOR 2.1 computer code for in-vessel phase of the accident. In this scenario, the unavailability of all offsite and onsite power sources and the lack of cooling leads directly to core degradation, material relocation to the lower plenum and rupture of the reactor pressure vessel. MELCOR results were compared qualitatively and quantitatively with MAAP4 code results and show a good agreement.

  9. Karl R. Popper, 1992: About the EPR controversy

    Science.gov (United States)

    Combourieu, Marie-Christine

    1992-10-01

    Sir K. R. Popper's experimental schemes challenge the Copenhagen interpretation of quantum theory, principally Heisenberg's indeterminacy relations and the EPR paradox. “The so-called Einstein-Podolsky-Rosen paradox is not a paradox. It is a theoretical statement in expectation of an interpretation,” says K. R. Popper in this interview. “My experiment ought to be a classical experiment. It is very simple and free from any additional assumption. It should really be done.”

  10. EPR study of spermine interaction with multilamellar phosphatidylcholine liposomes.

    Science.gov (United States)

    Momo, F; Wisniewska, A; Stevanato, R

    1995-11-22

    The interaction of spermine with egg-yolk phosphatidylcholine liposomes was investigated. The EPR spin labeling technique evidenced that spermine induces modifications of some membrane functions of biological interest like water permeability and is a possible modulator of diffusion processes for charged and polar molecules. The association constant for a hypothesized complex between spermine and the phosphate group of phosphatidylcholine was evaluated by enzymatic methods.

  11. EPR = ER, scattering amplitude and entanglement entropy change

    Energy Technology Data Exchange (ETDEWEB)

    Seki, Shigenori, E-mail: sigenori@hanyang.ac.kr [Research Institute for Natural Science, Hanyang University, Seoul 133-791 (Korea, Republic of); Sin, Sang-Jin, E-mail: sjsin@hanyang.ac.kr [Department of Physics, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2014-07-30

    We study the causal structure of the minimal surface of the four-gluon scattering, and find a world-sheet wormhole parametrized by Mandelstam variables, thereby demonstrate the EPR = ER relation for gluon scattering. We also propose that scattering amplitude is the change of the entanglement entropy by generalizing the holographic entanglement entropy of Ryu–Takayanagi to the case where two regions are divided in space–time.

  12. Copenhagen vs Everett, teleportation, and ER=EPR

    Energy Technology Data Exchange (ETDEWEB)

    Susskind, Leonard [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University, Stanford, CA (United States)

    2016-06-15

    Quantum gravity may have as much to tell us about the foundations and interpretation of quantum mechanics as it does about gravity. The Copenhagen interpretation of quantum mechanics and Everett's Relative State Formulation are complementary descriptions which in a sense are dual to one another. My purpose here is to discuss this duality in the light of the of ER=EPR conjecture. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. EPR and magnetism of the nanostructured natural carbonaceous material shungite

    Science.gov (United States)

    Augustyniak-Jabłokow, Maria Aldona; Yablokov, Yurii V.; Andrzejewski, Bartłomiej; Kempiński, Wojciech; Łoś, Szymon; Tadyszak, Krzysztof; Yablokov, Mikhail Y.; Zhikharev, Valentin A.

    2010-04-01

    The X-band EPR and magnetic susceptibility in the temperature range 4.2-300 K study of the shungite-I, natural nanostructured material from the deposit of Shunga are reported. Obtained results allow us to assign the EPR signal to conduction electrons, estimate their number, N P, and evaluate the Pauli paramagnetism contribution to shungite susceptibility. A small occupation (~5%) of the localized nonbonding π states in the zigzag edges of the open-ended graphene-like layers and/or on σ ( sp 2+ x ) orbitals in the curved parts of the shungite globules has been also revealed. The observed temperature dependence of the EPR linewidth can be explained by the earlier considered interaction of conduction π electrons with local phonon modes associated with the vibration of peripheral carbon atoms of the open zigzag-type edges and with peripheral carbon atoms cross-linking different nanostructures. The relaxation time T 2 and diffusion time T D are found to have comparable values (2.84 × 10-8 and 1.73 × 10-8 s at 5.2 K, respectively), and similar dependence on temperature. The magnetic measurements have revealed the suppression of orbital diamagnetism due to small amount of large enough fragments of the graphene layers.

  14. EPR investigation of some traditional oriental irradiated spices

    Science.gov (United States)

    Duliu, Octavian G.; Georgescu, Rodica; Ali, Shaban Ibrahim

    2007-06-01

    The 9.50 GHz electron paramagnetic resonance (EPR) spectra of unirradiated and 60Co γ-ray irradiated cardamom ( Elettaria cardamomum L. Maton, Zingiberaceae), ginger (( Zingiber officinale Rosc., Zingiberaceae), and saffron ( Crocus sativus L., Iridaceae) have been investigated at room temperature. All unirradiated spices presented a weak resonance line with g-factors around free-electron ones. After γ-ray irradiation at an absorbed dose of up to 11.3 kGy, the presence of EPR spectra whose amplitude increase monotonously with the absorbed dose has been noticed with all spices. A 100 °C isothermal annealing of 11.3 kGy irradiated samples has shown a differential reduction of amplitude of various components that compose initial spectra, but even after 3.6 h of thermal treatment, the remaining amplitude represents no less then 30% of the initial ones. The same peculiarities have been noticed after 83 days storage at room temperature but after 340 days storage at ambient conditions only irradiated ginger displays a weak signal that differs from those of unirradiated sample. All these factors could be taken into account in establishing at which extent the EPR is suitable to evidence any irradiation treatment applied to these spices.

  15. EPR investigation of some traditional oriental irradiated spices

    Energy Technology Data Exchange (ETDEWEB)

    Duliu, Octavian G. [University of Bucharest, Department of Atomic and Nuclear Physics, Magurele, C.P. MG-11, RO-077125 Bucharest (Romania)]. E-mail: duliu@pcnet.ro; Georgescu, Rodica [National Institute for Physics and Nuclear Engineering -Horia Hulubei, C.P. MG-6, RO-077125 Bucharest (Romania); Ali, Shaban Ibrahim [University of Bucharest, Department of Atomic and Nuclear Physics, Magurele, C.P. MG-11, RO-077125 Bucharest (Romania)

    2007-06-15

    The 9.50 GHz electron paramagnetic resonance (EPR) spectra of unirradiated and {sup 60}Co {gamma}-ray irradiated cardamom (Elettaria cardamomum L. Maton, Zingiberaceae), ginger ((Zingiber officinale Rosc., Zingiberaceae), and saffron (Crocus sativus L., Iridaceae) have been investigated at room temperature. All unirradiated spices presented a weak resonance line with g-factors around free-electron ones. After {gamma}-ray irradiation at an absorbed dose of up to 11.3 kGy, the presence of EPR spectra whose amplitude increase monotonously with the absorbed dose has been noticed with all spices. A 100 {sup o}C isothermal annealing of 11.3 kGy irradiated samples has shown a differential reduction of amplitude of various components that compose initial spectra, but even after 3.6 h of thermal treatment, the remaining amplitude represents no less then 30% of the initial ones. The same peculiarities have been noticed after 83 days storage at room temperature but after 340 days storage at ambient conditions only irradiated ginger displays a weak signal that differs from those of unirradiated sample. All these factors could be taken into account in establishing at which extent the EPR is suitable to evidence any irradiation treatment applied to these spices.

  16. TL, EPR and optical absorption in natural grossular crystal

    Energy Technology Data Exchange (ETDEWEB)

    Yauri, J.M. [Institute of Physics, University of Sao Paulo, Rua do Matao, Travessa R, 187, CEP 05508-900, Sao Paulo (Brazil); Department of Physics, University of San Agustin, Av. Independencia S/N, Arequipa (Peru); Cano, N.F. [Institute of Physics, University of Sao Paulo, Rua do Matao, Travessa R, 187, CEP 05508-900, Sao Paulo (Brazil)], E-mail: nilocano@dfn.if.usp.br; Watanabe, S. [Institute of Physics, University of Sao Paulo, Rua do Matao, Travessa R, 187, CEP 05508-900, Sao Paulo (Brazil)

    2008-10-15

    Grossular is one of six members of silicate Garnet group. Two samples GI and GII have been investigated concerning their luminescence thermally stimulated (TL). EPR and optical absorption and the measurements were carried out to find out whether or not same point defects are responsible for all three properties. Although X-rays diffraction analysis has shown that both GI and GII have practically the same crystal structure of a standard grossular crystal, they presented different behavior in many aspects. The TL glow curve shape, TL response to radiation dose, the effect of annealing at high temperatures before irradiation, the dependence of UV bleaching parameters on peak temperature, all of them differ going from GI to GII. The EPR signals around g=2.0 as well as at g=4.3 and 6.0 have much larger intensity in GI than in GII. Very high temperature (>800 deg. C) annealing causes large increase in the bulk background absorption in GI, however, only very little in GII. In the cases of EPR and optical absorption, the difference in their behavior can be attributed to Fe{sup 3+} ions; however, in the TL case one cannot and the cause was not found as yet.

  17. Peptide-membrane Interactions by Spin-labeling EPR

    Science.gov (United States)

    Smirnova, Tatyana I.; Smirnov, Alex I.

    2016-01-01

    Site-directed spin labeling (SDSL) in combination with Electron Paramagnetic Resonance (EPR) spectroscopy is a well-established method that has recently grown in popularity as an experimental technique, with multiple applications in protein and peptide science. The growth is driven by development of labeling strategies, as well as by considerable technical advances in the field, that are paralleled by an increased availability of EPR instrumentation. While the method requires an introduction of a paramagnetic probe at a well-defined position in a peptide sequence, it has been shown to be minimally destructive to the peptide structure and energetics of the peptide-membrane interactions. In this chapter, we describe basic approaches for using SDSL EPR spectroscopy to study interactions between small peptides and biological membranes or membrane mimetic systems. We focus on experimental approaches to quantify peptide-membrane binding, topology of bound peptides, and characterize peptide aggregation. Sample preparation protocols including spin-labeling methods and preparation of membrane mimetic systems are also described. PMID:26477253

  18. The influence of additives on beer stability investigated by EPR spectroscopy

    Science.gov (United States)

    Brezová, Vlasta; Polovka, Martin; Staško, Andrej

    2002-04-01

    In thermally-accelerated aging followed by EPR spectroscopy of beer samples of various stabilities, free radical 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPOL) was shown to be an effective indicator of the breakdown of a sample's stability, comparable to the commonly used spin trapping agent α-phenyl- N- tert-butylnitrone (PBN). Both indicators were then employed to investigate the influence of additives on beer stability. The addition of L-ascorbic acid (ASC) to the beer samples accelerated the radical processes and a lower stability was found. DL-α-tocopherol (α-TOC) did not influence beer stability significantly (probably due to its limited solubility). Na 2SO 3, described as a very effective stabilizer in experiments with the PBN spin trap, was found not to be effective using the TEMPOL indicator. This is probably due to inhibition in the formation of spin adducts or their degradation by Na 2SO 3.

  19. Dosimetry implant for treating restenosis and hyperplasia

    Science.gov (United States)

    Srivastava, Suresh; Gonzales, Gilbert R; Howell, Roger W; Bolch, Wesley E; Adzic, Radoslav

    2014-09-16

    The present invention discloses a method of selectively providing radiation dosimetry to a subject in need of such treatment. The radiation is applied by an implant comprising a body member and .sup.117mSn electroplated at selected locations of the body member, emitting conversion electrons absorbed immediately adjacent selected locations while not affecting surrounding tissue outside of the immediately adjacent area.

  20. Optically stimulated luminescence techniques in retrospective dosimetry

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Murray, A.S.

    2001-01-01

    Optically stimulated luminescence signals from natural quartz and feldspar are now used routinely in dating geological and archaeological materials. More recently they have also been employed in accident dosimetry, i.e. the retrospective assessment of doses received as a result of a nuclear...

  1. Development of A-bomb survivor dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Kerr, G.D.

    1995-12-31

    An all important datum in risk assessment is the radiation dose to individual survivors of the bombings in Hiroshima and Nagasaki. The first set of dose estimates for survivors was based on a dosimetry system developed in 1957 by the Oak Ridge National Laboratory (ORNL). These Tentative 1957 Doses (T57D) were later replaced by a more extensive and refined set of Tentative 1965 Doses (T65D). The T65D system of dose estimation for survivors was also developed at ORNL and served as a basis for risk assessment throughout the 1970s. In the late 1970s, it was suggested that there were serious inadequacies with the T65D system, and these inadequacies were the topic of discussion at two symposia held in 1981. In early 1983, joint US- Japan research programs were established to conduct a thorough review of all aspects of the radiation dosimetry for the Hiroshima and Nagasaki A-bomb survivors. A number of important contributions to this review were made by ORNL staff members. The review was completed in 1986 and a new Dosimetry System 1986 (DS86) was adopted for use. This paper discusses the development of the various systems of A-bomb survivor dosimetry, and the status of the current DS86 system as it is being applied in the medical follow-up studies of the A-bomb survivors and their offspring.

  2. Computational Techniques of Electromagnetic Dosimetry for Humans

    Science.gov (United States)

    Hirata, Akimasa; Fujiwara, Osamu

    There has been increasing public concern about the adverse health effects of human exposure to electromagnetic fields. This paper reviews the rationale of international safety guidelines for human protection against electromagnetic fields. Then, this paper also presents computational techniques to conduct dosimetry in anatomically-based human body models. Computational examples and remaining problems are also described briefly.

  3. Thermoluminescence Dosimetry Applied to Radiation Protection

    DEFF Research Database (Denmark)

    Christensen, Poul; Bøtter-Jensen, Lars; Majborn, Benny

    1982-01-01

    This is a general review of the present state of the development and application of thermoluminescence dosimetry (TLD) for radiation protection purposes. A description is given of commonly used thermoluminescent dosimeters and their main dosimetric properties, e.g. energy response, dose range...

  4. Dosimetry implant for treating restenosis and hyperplasia

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Suresh; Gonzales, Gilbert R; Howell, Roger W; Bolch, Wesley E; Adzic, Radoslav

    2014-09-16

    The present invention discloses a method of selectively providing radiation dosimetry to a subject in need of such treatment. The radiation is applied by an implant comprising a body member and .sup.117mSn electroplated at selected locations of the body member, emitting conversion electrons absorbed immediately adjacent selected locations while not affecting surrounding tissue outside of the immediately adjacent area.

  5. Intra-Operative Dosimetry in Prostate Brachytherapy

    Science.gov (United States)

    2007-11-01

    CT-based post-implant dosimetry. Figure 1: System concept for TRUS and C-arm fusion B BODY B.1 Brief System Concept The system concept for...C-arm calibration - is it really necessary?,” MICCAI, pp. 639–646, 2005. 10. Brainlab, Inc., Heimstetten, Germany, Vector Vision. 11. Medtronic

  6. Advances in reference and transfer dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Desrosiers, M.F. [Ionizing Radiation Division, Physics Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

    1999-07-01

    All prerequisites are now in place to create a fundamentally and radically different type of calibration service for the radiation processing industry. Advancements in dosimetry and information technology can be combined to provide industry with on-line calibrations, on demand at a low cost. The remote calibration service will serve as a basis for other areas of metrology. (Author)

  7. Personnel radiation dosimetry symposium: program and abstracts

    Energy Technology Data Exchange (ETDEWEB)

    1984-10-01

    The purpose was to provide applied and research dosimetrists with sufficient information to evaluate the status and direction of their programs relative to the latest guidelines and techniques. A technical program was presented concerning experience, requirements, and advances in gamma, beta, and neutron personnel dosimetry.

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

    Science.gov (United States)

    Polymeris, G S; Giannoulatou, V; Kyriakidou, A; Sfampa, I K; Theodorou, G S; Şahiner, E; Meriç, N; Kitis, G; Paraskevopoulos, K M

    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 (SiO2 45, Na2O 24.5, CaO 24.5, P2O5 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 20-40μm 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 16min 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 of the 58S sol-gel bioactive glass

  9. Kinetic analysis-based quantitation of free radical generation in EPR spin trapping.

    Science.gov (United States)

    Samouilov, Alexandre; Roubaud, Valerie; Kuppusamy, Periannan; Zweier, Jay L

    2004-11-01

    Because short-lived reactive oxygen radicals such as superoxide have been implicated in a variety of disease processes, methods to measure their production quantitatively in biological systems are critical for understanding disease pathophysiology. Electron paramagnetic resonance (EPR) spin trapping is a direct and sensitive technique that has been used to study radical formation in biological systems. Short-lived oxygen free radicals react with the spin trap and produce paramagnetic adducts with much higher stability than that of the free radicals. In many cases, the quantity of the measured adduct is considered to be an adequate measure of the amount of the free radical generated. Although the intensity of the EPR signal reflects the magnitude of free radical generation, the actual quantity of radicals produced may be different due to modulation of the spin adduct kinetics caused by a variety of factors. Because the kinetics of spin trapping in biochemical and cellular systems is a complex process that is altered by the biochemical and cellular environment, it is not always possible to define all of the reactions that occur and the related kinetic parameters of the spin-trapping process. We present a method based on a combination of measured kinetic data for the formation and decay of the spin adduct alone with the parameters that control the kinetics of spin trapping and radical generation. The method is applied to quantitate superoxide trapping with 5-diethoxyphosphoryl-5-methyl-1-pyrroline N-oxide (DEPMPO). In principle, this method is broadly applicable to enable spin trapping-based quantitative determination of free radical generation in complex biological systems.

  10. Film dosimetry in conformal radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Danciu, C.; Proimos, B.S. [Patras Univ. (Greece). Dept. of Medical Physics

    1995-12-01

    Dosimetry, through a film sandwiched in a transverse cross-section of a solid phantom, is a method of choice in Conformal Radiotherapy because: (a) the blackness (density) of the film at each point offers a measure of the total dose received at that point, and (b) the film is easily calibrated by exposing a film strip in the same cross-section, through a stationary field. The film must therefore have the following properties: (a) it must be slow, in order not to be overexposed, even at a therapeutic dose of 200 cGy, and (b) the response of the film (density versus dose curve) must be independent of the photon energy spectrum. A few slow films were compared. It was found that the Kodak X-Omat V for therapy verification was the best choice. To investigate whether the film response was independent of the photon energy, response curves for six depths, starting from the depth of maximum dose to the depth of 25 cm, in solid phantom were derived. The vertical beam was perpendicular to the anterior surface of the phantom, which was at the distance of 100 cm from the source and the field was 15x15 cm at that distance. This procedure was repeated for photon beams emitted by a Cobalt-60 unit, two 6 MV and 15 MV Linear Accelerators, as well as a 45 MV Betatron. For each of those four different beams the film response was the same for all six depths. The results, as shown in the diagrams, are very satisfactory. The response curve under a geometry similar to that actually applied, when the film is irradiated in a transverse cross-section of the phantom, was derived. The horizontal beam was almost parallel (angle of 85) to the plane of the film. The same was repeated with the central ray parallel to the film (angle 90) and at a distance of 1.5 cm from the horizontal film. The field size was again 15x15 at the lateral entrance surface of the beam. The response curves remained the same, as when the beam was perpendicular to the films.

  11. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1993-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  12. Public debate about the EPR nuclear power plant at Flamanville; Debat public sur la centrale nucleaire EPR a Flamanville

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    The project of building of he EPR reactor at Flamanville (Manche, France) has been submitted to the public debate. This document includes a presentation of the project and of the rules of the public debate, a synthesis of the file made by the prime contractor (EDF), a synthesis of the collective book of national actors concerned by the project (a group of associations for environment protection, Areva company, the ministries of economy and ecology, Global Chance, association of pro-nuclear ecologists (AEPN), 'Sortir du Nucleaire' (out-of nuclear) network, group of scientists for the information about nuclear (GSIEN), association for the promotion of the Flamanville site (Proflam), French nuclear energy society (SFEN) in association with 'Sauvons le Climat' (let's save climate), regional collective association 'EPR non merci, ni ailleurs, ni ici' (EPR, no thanks, neither elsewhere, nor here), NegaWatt), and 5 detailed books of actors: ACRO (association for the control of radioactivity in Western France), CFDT and CGT syndicates, the economic and social council of Basse Normandie region, and Proflam. (J.S.)

  13. Intrinsic dosimetry. Properties and mechanisms of thermoluminescence in commercial borosilicate glass

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Richard A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2012-10-01

    Intrinsic dosimetry is the method of measuring total absorbed dose received by the walls of a container holding radioactive material. By considering the total absorbed dose received by a container in tandem with the physical characteristics of the radioactive material housed within that container, this method has the potential to provide enhanced pathway information regarding the history of the container and its radioactive contents. The latest in a series of experiments designed to validate and demonstrate this newly developed tool are reported. Thermoluminescence (TL) dosimetry was used to measure dose effects on raw stock borosilicate container glass up to 70 days after gamma ray, x-ray, beta particle or ultraviolet irradiations at doses from 0.15 to 20 Gy. The TL glow curve when irradiated with 60Co was separated into five peaks: two relatively unstable peaks centered near 120 and 165°C, and three relatively stable peaks centered near 225, 285, and 360°C. Depending on the borosilicate glass source, the minimum measurable dose using this technique is 0.15-0.5 Gy, which is roughly equivalent to a 24 hr irradiation at 1 cm from a 50-165 ng source of 60Co. Differences in TL glow curve shape and intensity were observed for the glasses from different geographical origins. These differences can be explained by changes in the intensities of the five peaks. Electron paramagnetic resonance (EPR) and multivariate statistical methods were used to relate the TL intensity and peaks to electron/hole traps and compositional variations.

  14. A Regional PD Strategy for EPR Systems: Evidence-Based IT Development

    DEFF Research Database (Denmark)

    Simonsen, Jesper; Hertzum, Morten

    2006-01-01

    systems. We present this PD strategy and our related research on evidence-based IT development. We report from a newly completed PD experiment with EPR in the region conducted through a close collaboration compris-ing a neurological stroke unit, the region’s EPR unit, the vendor, as well as the authors.......One of the five regions in Denmark has initiated a remark-able and alternative strategy for the development of Elec-tronic Patient Record (EPR) systems. This strategy is driven by Participatory Design (PD) experiments and based on evidence of positive effects on the clinical practice when using EPR...

  15. Thermoluminescence in medical dosimetry; Termoluminiscencia en dosimetria medica

    Energy Technology Data Exchange (ETDEWEB)

    Rivera, T., E-mail: trivera@ipn.mx [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico)

    2011-10-15

    The dosimetry by thermoluminescence (Tl) is applied in the entire world for the dosimetry of ionizing radiations specially to personal and medical dosimetry. This dosimetry method has been very interesting for measures in vivo because the Tl dosimeters have the advantage of being very sensitive in a very small volume and they are also equivalent to tissue and they do not need additional accessories (for example, cable, electrometer, etc.) The main characteristics of the diverse Tl materials to be used in the radiation measures and practical applications are: the Tl curve, the share homogeneity, the signal stability after the irradiation, precision and exactitude, the response in function with the dose and the energy influence. In this work a brief summary of the advances of the radiations dosimetry is presented by means of the thermally stimulated luminescence and its application to the dosimetry in radiotherapy. (Author)

  16. TU-F-201-00: Radiochromic Film Dosimetry Update

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

    Since the introduction of radiochromic films (RCF) for radiation dosimetry, the scope of RCF dosimetry has expanded steadily to include many medical applications, such as radiation therapy and diagnostic radiology. The AAPM Task Group (TG) 55 published a report on the recommendations for RCF dosimetry in 1998. As the technology is advancing rapidly, and its routine clinical use is expanding, TG 235 has been formed to provide an update to TG-55 on radiochromic film dosimetry. RCF dosimetry applications in clinical radiotherapy have become even more widespread, expanding from primarily brachytherapy and radiosurgery applications, and gravitating towards (but not limited to) external beam therapy (photon, electron and protons), such as quality assurance for IMRT, VMAT, Tomotherapy, SRS/SRT, and SBRT. In addition, RCF applications now extend to measurements of radiation dose in particle beams and patients undergoing medical exams, especially fluoroscopically guided interventional procedures and CT. The densitometers/scanners used for RCF dosimetry have also evolved from the He-Ne laser scanner to CCD-based scanners, including roller-based scanner, light box-based digital camera, and flatbed color scanner. More recently, multichannel RCF dosimetry introduced a new paradigm for external beam dose QA for its high accuracy and efficiency. This course covers in detail the recent advancements in RCF dosimetry. Learning Objectives: Introduce the paradigm shift on multichannel film dosimetry Outline the procedures to achieve accurate dosimetry with a RCF dosimetry system Provide comprehensive guidelines on RCF dosimetry for various clinical applications One of the speakers has a research agreement from Ashland Inc., the manufacturer of Gafchromic film.

  17. The possible use of EPR spectroscopy for paint pigment identification

    Energy Technology Data Exchange (ETDEWEB)

    Troup, G.J.; Hutton, D.R. [Monash Univ., Clayton, VIC (Australia). Dept. of Physics; Bacci, M.; Lotti, F.; Casini, A.; Picollo, M. [Istituto di Ricerca sulle Onde Elettromagnetiche, Florence, Italy (Italy)

    1996-12-31

    Full text: Visible and near-infra-red reflectance spectroscopy are now routinely used for the identification of paint pigments in Renaissance painting, thus playing a part in authentication and restoration. Since most of the pigments are minerals, and many minerals either contain traces of paramagnetic ions, or have paramagnetic ions in their main components (e.g., chromic oxide, haematite), it seemed logical to determine whether EPR could distinguish between different pigments. 14 pigments of different colours were tested in a Varian E-12 EPR spectrometer, at a frequency of {approx} 9.1 GHz. Measurements were made at room ({approx} 20 deg C) and liquid N{sub 2} temperatures, in the standard special quartz sample tubes. The active volume is 0. 15 ml, but at most, a volume of sample (powder) one tenth of this was used. The spectra (to be shown) clearly demonstrate that EPR can distinguish between different pigments. The power was 1 milliwatt, the modulation amplitude 4 gauss, the total field sweep 10,000 gauss, centred 5000 gauss and the amplification between 10{sup 2} and 10{sup 4}, as indicated on the charts. The signal to noise ratio is excellent, and sensitivity could be increased (if necessary) by a factor of {approx} 10{sup 3}, thus allowing much smaller samples to be tested. Because the signals are so strong it should be possible to scan at least small painted canvases by the following non-destructive technique, using existing equipment. All that is required is a modified resonant cavity; it must have a high Q, and a slot where the magnetic field is maximum, and the electric field zero. The canvas can thus be placed flush with the waveguide, to interact with the microwave magnetic field emanating from the slot

  18. Photodegradation of petroleum under Na and Hg lamps by EPR

    Energy Technology Data Exchange (ETDEWEB)

    Mauro, Eduardo di; Melo, Fernando Alves de; Turini, Marilene; Campos, Ariana de [Universidade Estadual de Londrina (UEL), PR (Brazil). Dept. of Physics; Guedes, Carmen Luisa Barbosa [Universidade Estadual de Londrina (UEL), PR (Brazil). Dept. of Chemistry; Mangrich, Antonio Salvio [Universidade Federal do Parana (UFPR), PR (Brazil). Dept. of Chemistry

    2002-07-01

    Full text: The environment has become frequent victim of the action of pollutants. This situation has been stimulating several scientific works in the attempt to monitor the self-defence of the environment and minimise the effects caused by these pollutants. The petroleum and its derived, among the several substances that attack the environment, occupy a distinction place in the pollution picture. In the present work, we studied the photodegradation of the Arabian Light and Brazilian (Campos Basin- RJ) oils. Sample of theses oils were irradiated by different time periods in a reactor equipped with Na and Hg vapour lamps, whose emission spectra have different features. The irradiated and non-irradiated samples were subjected to Electron Paramagnetic Resonance (EPR) analysis in a BRUKER (ESP-300) equipment, which operates in the X band (9 GHz) at room temperature. The EPR spectra showed similar features to the two oils. The EPR spectra are composed of a intense signal (one line) with g (spectroscopic factor) about two relative to free radicals and groups of eight lines correspondent to vanadyl porphyrinic compounds (VO{sup 2+}). The parameters of spin Hamiltonian were determined to the two detected paramagnetic species. The two oils irradiated by Na and Hg lamps showed variations in the values of g and {delta}H (linewidth) of the paramagnetic species. The changes in the parameters are the most significant in Brazilian petroleum samples irradiated by Hg lamp. The modifications in the linewidth of free radicals of the Arabian Light petroleum have the same tendency to the two utilised lamps. (author)

  19. Hanford External Dosimetry Technical Basis Manual PNL-MA-842

    Energy Technology Data Exchange (ETDEWEB)

    Rathbone, Bruce A.

    2005-02-25

    The Hanford External Dosimetry Technical Basis Manual PNL-MA-842 documents the design and implementation of the external dosimetry system used at Hanford. The manual describes the dosimeter design, processing protocols, dose calculation methodology, radiation fields encountered, dosimeter response characteristics, limitations of dosimeter design under field conditions, and makes recommendations for effective use of the dosimeters in the field. The manual describes the technical basis for the dosimetry system in a manner intended to help ensure defensibility of the dose of record at Hanford and to demonstrate compliance with 10 CFR 835, DOELAP, DOE-RL, ORP, PNSO, and Hanford contractor requirements. The dosimetry system is operated by PNNL’s Hanford External Dosimetry Program which provides dosimetry services to all Hanford contractors. The primary users of this manual are DOE and DOE contractors at Hanford using the dosimetry services of PNNL. Development and maintenance of this manual is funded directly by DOE and DOE contractors. Its contents have been reviewed and approved by DOE and DOE contractors at Hanford through the Hanford Personnel Dosimetry Advisory Committee which is chartered and chaired by DOE-RL and serves as means of coordinating dosimetry practices across contractors at Hanford. This manual was established in 1996. Since inception, it has been revised many times and maintained by PNNL as a controlled document with controlled distribution. Rev. 0 marks the first revision to be released through PNNL’s Electronic Records & Information Capture Architecture (ERICA) database.

  20. Quality assessment of automatically extracted data from GPs' EPR.

    Science.gov (United States)

    de Clercq, Etienne; Moreels, Sarah; Van Casteren, Viviane; Bossuyt, Nathalie; Goderis, Geert; Bartholomeeusen, Stefaan

    2012-01-01

    There are many secondary benefits to collecting routine primary care data, but we first need to understand some of the properties of this data. In this paper we describe the method used to assess the PPV and sensitivity of data extracted from Belgian GPs' EPR (diagnoses, drug prescriptions, referrals, and certain parameters), using data collected through an electronic questionnaire as a gold standard. We describe the results of the ResoPrim phase 2 project, which involved 4 software systems and 43 practices (10,307 patients). This method of assessment could also be applied to other research networks.

  1. EPR of Mononuclear Non-Heme Iron Proteins

    OpenAIRE

    Gaffney, Betty J.

    2009-01-01

    Flexible geometry of three- to six-protein side-chain ligands to non-heme iron in proteins is the basis for widely diverse reactivites ranging from iron transport to redox chemistry. The gap between fixed states determined by x-ray analysis can be filled by spectroscopic study of trapped intermediates. EPR is a versatile and relatively quick approach to defining intermediate states in terms of the geometry and electronic structures of iron. A number of examples in which the iron chemistry of ...

  2. EPR spectra of four gadolinium complexes with Schiff bases

    Institute of Scientific and Technical Information of China (English)

    姚克敏; 陈德余; 封子先; 李冬成; 冯亚菲; 何玲

    1995-01-01

    EPR spectra of four new gadolinium complexes with Schiff bases in polycrystalline powder and those of these complexes in three organic solvents were investigated at different temperatures. It has been observed for the first time that their freezing solution spectra are quite different from each other. In THF one peak was observed only, but there were three peaks and typical "U" spectral features appearing in DMF and DMSO at low temperatures. On the basis of spin Hamiltonian of S = 7/2 system, the correlations between crystal field strength in complexes and local symmetry around Gd3+ ions are discussed.

  3. EPR identification of irradiated Monascus purpureus red pigment

    Energy Technology Data Exchange (ETDEWEB)

    Duliu, Octavian G. E-mail: odlu@scut.fizica.unibuc.ro; Ferdes, Mariana; Ferdes, Ovidiu S

    2000-01-01

    Fresh red alimentary pigment extracted from Monascus purpureus fungus exhibits an intense EPR line consisting of a single, narrow line, attributed to a quinone radical. When irradiated with 7 MeV electrons or {sup 60}Co {gamma}-rays, the amplitude of this line increased with the absorbed dose following a saturation exponential dependency up to 10 kGy. During annealing treatment (isothermal heating at 100 deg. C) the irradiation centers decay exponentially with a half-life time of 2.30 min.

  4. EPR identification of irradiated Monascus purpureus red pigment

    Science.gov (United States)

    Duliu, Octavian G.; Ferdes, Mariana; Ferdes, Ovidiu S.

    2000-01-01

    Fresh red alimentary pigment extracted from Monascus purpureus fungus exhibits an intense EPR line consisting of a single, narrow line, attributed to a quinone radical. When irradiated with 7 MeV electrons or 60Co γ-rays, the amplitude of this line increased with the absorbed dose following a saturation exponential dependency up to 10 kGy. During annealing treatment (isothermal heating at 100°C) the irradiation centers decay exponentially with a half-life time of 2.30 min.

  5. Absolute and relative dosimetry for ELIMED

    Science.gov (United States)

    Cirrone, G. A. P.; Cuttone, G.; Candiano, G.; Carpinelli, M.; Leonora, E.; Lo Presti, D.; Musumarra, A.; Pisciotta, P.; Raffaele, L.; Randazzo, N.; Romano, F.; Schillaci, F.; Scuderi, V.; Tramontana, A.; Cirio, R.; Marchetto, F.; Sacchi, R.; Giordanengo, S.; Monaco, V.

    2013-07-01

    The definition of detectors, methods and procedures for the absolute and relative dosimetry of laser-driven proton beams is a crucial step toward the clinical use of this new kind of beams. Hence, one of the ELIMED task, will be the definition of procedures aiming to obtain an absolute dose measure at the end of the transport beamline with an accuracy as close as possible to the one required for clinical applications (i.e. of the order of 5% or less). Relative dosimetry procedures must be established, as well: they are necessary in order to determine and verify the beam dose distributions and to monitor the beam fluence and the energetic spectra during irradiations. Radiochromic films, CR39, Faraday Cup, Secondary Emission Monitor (SEM) and transmission ionization chamber will be considered, designed and studied in order to perform a fully dosimetric characterization of the ELIMED proton beam.

  6. Trigeminal neuralgia treatment dosimetry of the Cyberknife

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Anthony [Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Lo, Anthony T., E-mail: tonyho22003@yahoo.com [Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Dieterich, Sonja; Soltys, Scott G.; Gibbs, Iris C. [Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Chang, Steve G.; Adler, John R. [Department of Neurosurgery, Stanford University, Stanford, CA (United States)

    2012-04-01

    There are 2 Cyberknife units at Stanford University. The robot of 1 Cyberknife is positioned on the patient's right, whereas the second is on the patient's left. The present study examines whether there is any difference in dosimetry when we are treating patients with trigeminal neuralgia when the target is on the right side or the left side of the patient. In addition, we also study whether Monte Carlo dose calculation has any effect on the dosimetry. We concluded that the clinical and dosimetric outcomes of CyberKnife treatment for trigeminal neuralgia are independent of the robot position. Monte Carlo calculation algorithm may be useful in deriving the dose necessary for trigeminal neuralgia treatments.

  7. Absolute and relative dosimetry for ELIMED

    Energy Technology Data Exchange (ETDEWEB)

    Cirrone, G. A. P.; Schillaci, F.; Scuderi, V. [INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania, Italy and Institute of Physics Czech Academy of Science, ELI-Beamlines project, Na Slovance 2, Prague (Czech Republic); Cuttone, G.; Candiano, G.; Musumarra, A.; Pisciotta, P.; Romano, F. [INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Carpinelli, M. [INFN Sezione di Cagliari, c/o Dipartimento di Fisica, Università di Cagliari, Cagliari (Italy); Leonora, E.; Randazzo, N. [INFN-Sezione di Catania, Via Santa Sofia 64, Catania (Italy); Presti, D. Lo [INFN-Sezione di Catania, Via Santa Sofia 64, Catania, Italy and Università di Catania, Dipartimento di Fisica e Astronomia, Via S. Sofia 64, Catania (Italy); Raffaele, L. [INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania, Italy and INFN-Sezione di Catania, Via Santa Sofia 64, Catania (Italy); Tramontana, A. [INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania, Italy and Università di Catania, Dipartimento di Fisica e Astronomia, Via S. Sofia 64, Catania (Italy); Cirio, R.; Sacchi, R.; Monaco, V. [INFN, Sezione di Torino, Via P.Giuria, 1 10125 Torino, Italy and Università di Torino, Dipartimento di Fisica, Via P.Giuria, 1 10125 Torino (Italy); Marchetto, F.; Giordanengo, S. [INFN, Sezione di Torino, Via P.Giuria, 1 10125 Torino (Italy)

    2013-07-26

    The definition of detectors, methods and procedures for the absolute and relative dosimetry of laser-driven proton beams is a crucial step toward the clinical use of this new kind of beams. Hence, one of the ELIMED task, will be the definition of procedures aiming to obtain an absolute dose measure at the end of the transport beamline with an accuracy as close as possible to the one required for clinical applications (i.e. of the order of 5% or less). Relative dosimetry procedures must be established, as well: they are necessary in order to determine and verify the beam dose distributions and to monitor the beam fluence and the energetic spectra during irradiations. Radiochromic films, CR39, Faraday Cup, Secondary Emission Monitor (SEM) and transmission ionization chamber will be considered, designed and studied in order to perform a fully dosimetric characterization of the ELIMED proton beam.

  8. Technical basis document for internal dosimetry

    CERN Document Server

    Hickman, D P

    1991-01-01

    This document provides the technical basis for the Chem-Nuclear Geotech (Geotech) internal dosimetry program. Geotech policy describes the intentions of the company in complying with radiation protection standards and the as low as reasonably achievable (ALARA) program. It uses this policy and applicable protection standards to derive acceptable methods and levels of bioassay to assure compliance. The models and computational methods used are described in detail within this document. FR-om these models, dose- conversion factors and derived limits are computed. These computations are then verified using existing documentation and verification information or by demonstration of the calculations used to obtain the dose-conversion factors and derived limits. Recommendations for methods of optimizing the internal dosimetry program to provide effective monitoring and dose assessment for workers are provided in the last section of this document. This document is intended to be used in establishing an accredited dosi...

  9. Criticality accident dosimetry with ESR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    D`Errico, F. [DCMN, Universita degli Studi di Pisa (Italy); Fattibene, P.; Onori, S.; Pantaloni, M. [Istituto Superiore di Sanita, Rome (Italy). Lab. di Fisica

    1997-01-01

    The suitability of the ESR alanine and sugar detectors for criticality accident dosimetry was experimentally investigated during an intercomparison of dosimetry techniques. Tests were performed irradiating detectors both free-in-air and on-phantom during controlled criticality excursions at the SILENE reactor in Valduc, France. Several grays of absorbed dose were imparted in neutron gamma-ray fields of various relative intensities and spectral distributions. Analysed results confirmed the potential of these systems which can immediately provide an acute dose assessment with an average underestimate of 30% in the various fields. This performance allows for the screening of severely exposed individuals and meets the IAEA recommendations on the early estimate of accident absorbed doses. (Author).

  10. Thermocurrent dosimetry with high purity aluminum oxide

    Energy Technology Data Exchange (ETDEWEB)

    Fullerton, G.D.; Cameron, J.R.; Moran, P.R.

    1976-01-01

    The application of thermocurrent (TC) to ionizing radiation dosimetry was studied. It was shown that TC in alumina (Al/sub 2/O/sub 3/) has properties that are suited to personnel dosimetry and environmental monitoring. TC dosimeters were made from thin disks of alumina. Aluminum electrodes were evaporated on each side: on one face a high voltage electrode and on the opposite face a measuring electrode encircled by a guard ring. Exposure to ionizing radiation resulted in stored electrons and holes in metastable trapping sites. The signal was read-out by heating the dosimeter with a voltage source and picnometer connected in series between the opposite electrodes. The thermally remobilized charge caused a transient TC. The thermogram, TC versus time or temperature, is similar to a TL glow curve. Either the peak current or the integrated current is a measure of absorbed dose. Six grades of alumina were studied from a total of four commercial suppliers. All six materials displayed radiation induced TC signals. Sapphire of uv-grade quality from the Adolf Meller Co. (AM) had the best dosimetry properties of those investigated. Sources of interference were studied. Thermal fading, residual signal and radiation damage do not limit TC dosimetry. Ultraviolet light can induce a TC response but it is readily excluded with uv-opaque cladding. Improper surface preparation prior to electrode evaporation was shown to cause interference. A spurious TC signal resulted from polarization of surface contaminants. Spurious TC was reduced by improved cleaning prior to electrode application. Polished surfaces resulted in blocking electrodes and caused a sensitivity shift due to radiation induced thermally activated polarization. This was not observed with rough cut surfaces.

  11. Report: dosimetry of diagnostic exams in nuclear medicine; Rapport: dosimetrie des explorations diagnostiques en medecine nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Touzery, C. [Centre Regional de Lutte Contre le Cancer de Bourgogne, Centre Georges-Francois Leclerc, 21 - Dijon (France); Aubert, B. [Institut Gustave Roussy, 94 - Villejuif (France); Caselles, O. [Centre Claudius-Regaud, 31 - Toulouse (France); Gardin, I. [Centre Henri Becquerel, 76 - Rouen (France); Guilhem, M.Th. [Centre Hospitalier Regional de la Source, 45 - Orleans (France); Laffont, S. [Centre Eugene-Marquis, 35 - Rennes (France); Lisbona, A. [Centre Regional de Lutte Contre le Cancer Rene-Gauducheau, 44 - Nantes (France)

    2002-07-01

    A compilation about dosimetry of diagnosis explorations in nuclear medicine is presented in this issue. Dosimetry tables of the different radiopharmaceuticals used in nuclear medicine give indications on absorbed and efficient doses according the patients age from one year to adult age. The doses received by a fetus during a lung scintigraphy realized for the pregnant woman susceptible to suffer of pulmonary emboli is presented. A table of efficient doses for the infants until the age of six months for the principal scintigraphy explorations realized in nuclear medicine are given. A chapter of theoretical headlines is devoted to dosimetry and the calculations methods of absorbed and efficient doses in function of patients age. A short chapter concerns the recommendations to explore nursing mothers by scintigraphy. A last chapter treats the efficient doses received during explorations using ionizing radiations in radiology and their place in annual natural irradiation scale. (N.C.)

  12. Fe (III - Galactomannan Solid and Aqueous Complexes: Potentiometric, EPR Spectroscopy and Thermal Data

    Directory of Open Access Journals (Sweden)

    Mercê Ana L. R.

    2001-01-01

    Full Text Available Galactomannans can be employed in food industries to modify the final rheological properties of the products. Since they are not absorbed by the living organisms they can also be used in dietary foods. The equilibria involving the interactions of Fe(III and galactomannans and arabinogalactan of several leguminous plants were characterized by potentiometric titrations and EPR spectroscopy. The log of the equilibrium constants for the formation of ML species, where M is the metal ion and L is the monomeric unit of the biopolymers, were 15.4, 14.1 and 18.5, for the galactomannans of C. fastuosa, L. leucocephala and S. macranthera, respectively. Log K values for protonated species (MHL were 3.1, 3.3, and were not detected for the galactomannan of S. macranthera. The log K values for the formation of ML2 were 14.1, 13.3 and 15.2, respectively. Early formation of insoluble products in the equilibrium with arabinogalactan and Fe(III prevented acquisition of reliable data. The solid complexes assays showed a great dipolar interaction between two Fe(III ions in the inner structure of the biopolymer which increased as the degree of substitution of the galactomannan decreased, and also showed the resulting thermal stability. The complexes impart a new possibility of providing essential metal ions in dietary foods since decomplexation of the complexes can occur at different pH values existing in the human body.

  13. Reconstructive dosimetry for cutaneous radiation syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Lima, C.M.A.; Lima, A.R.; Degenhardt, Ä.L.; Da Silva, F.C.A., E-mail: dasilva@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Valverde, N.J. [Fundacao Eletronuclear de Assistencia Medica, Rio de Janeiro, RJ (Brazil)

    2015-10-15

    According to the International Atomic Energy Agency (IAEA), a relatively significant number of radiological accidents have occurred in recent years mainly because of the practices referred to as potentially high-risk activities, such as radiotherapy, large irradiators and industrial radiography, especially in gammagraphy assays. In some instances, severe injuries have occurred in exposed persons due to high radiation doses. In industrial radiography, 80 cases involving a total of 120 radiation workers, 110 members of the public including 12 deaths have been recorded up to 2014. Radiological accidents in industrial practices in Brazil have mainly resulted in development of cutaneous radiation syndrome (CRS) in hands and fingers. Brazilian data include 5 serious cases related to industrial gammagraphy, affecting 7 radiation workers and 19 members of the public; however, none of them were fatal. Some methods of reconstructive dosimetry have been used to estimate the radiation dose to assist in prescribing medical treatment. The type and development of cutaneous manifestations in the exposed areas of a person is the first achievable gross dose estimation. This review article presents the state-of-the-art reconstructive dosimetry methods enabling estimation of local radiation doses and provides guidelines for medical handling of the exposed individuals. The review also presents the Chilean and Brazilian radiological accident cases to highlight the importance of reconstructive dosimetry. (author)

  14. Hanford Internal Dosimetry Project manual. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Carbaugh, E.H.; Bihl, D.E.; MacLellan, J.A.; Long, M.P.

    1994-07-01

    This document describes the Hanford Internal Dosimetry Project, as it is administered by Pacific Northwest Laboratory (PNL) in support of the US Department of Energy and its Hanford contractors. Project services include administrating the bioassay monitoring program, evaluating and documenting assessment of potential intakes and internal dose, ensuring that analytical laboratories conform to requirements, selecting and applying appropriate models and procedures for evaluating radionuclide deposition and the resulting dose, and technically guiding and supporting Hanford contractors in matters regarding internal dosimetry. Specific chapters deal with the following subjects: practices of the project, including interpretation of applicable DOE Orders, regulations, and guidance into criteria for assessment, documentation, and reporting of doses; assessment of internal dose, including summary explanations of when and how assessments are performed; recording and reporting practices for internal dose; selection of workers for bioassay monitoring and establishment of type and frequency of bioassay measurements; capability and scheduling of bioassay monitoring services; recommended dosimetry response to potential internal exposure incidents; quality control and quality assurance provisions of the program.

  15. Reconstructive dosimetry for cutaneous radiation syndrome.

    Science.gov (United States)

    Lima, C M A; Lima, A R; Degenhardt, Ä L; Valverde, N J; Silva, F C A da

    2015-10-01

    According to the International Atomic Energy Agency (IAEA), a relatively significant number of radiological accidents have occurred in recent years mainly because of the practices referred to as potentially high-risk activities, such as radiotherapy, large irradiators and industrial radiography, especially in gammagraphy assays. In some instances, severe injuries have occurred in exposed persons due to high radiation doses. In industrial radiography, 80 cases involving a total of 120 radiation workers, 110 members of the public including 12 deaths have been recorded up to 2014. Radiological accidents in industrial practices in Brazil have mainly resulted in development of cutaneous radiation syndrome (CRS) in hands and fingers. Brazilian data include 5 serious cases related to industrial gammagraphy, affecting 7 radiation workers and 19 members of the public; however, none of them were fatal. Some methods of reconstructive dosimetry have been used to estimate the radiation dose to assist in prescribing medical treatment. The type and development of cutaneous manifestations in the exposed areas of a person is the first achievable gross dose estimation. This review article presents the state-of-the-art reconstructive dosimetry methods enabling estimation of local radiation doses and provides guidelines for medical handling of the exposed individuals. The review also presents the Chilean and Brazilian radiological accident cases to highlight the importance of reconstructive dosimetry.

  16. Reconstructive dosimetry for cutaneous radiation syndrome

    Directory of Open Access Journals (Sweden)

    C.M.A. Lima

    2015-01-01

    Full Text Available According to the International Atomic Energy Agency (IAEA, a relatively significant number of radiological accidents have occurred in recent years mainly because of the practices referred to as potentially high-risk activities, such as radiotherapy, large irradiators and industrial radiography, especially in gammagraphy assays. In some instances, severe injuries have occurred in exposed persons due to high radiation doses. In industrial radiography, 80 cases involving a total of 120 radiation workers, 110 members of the public including 12 deaths have been recorded up to 2014. Radiological accidents in industrial practices in Brazil have mainly resulted in development of cutaneous radiation syndrome (CRS in hands and fingers. Brazilian data include 5 serious cases related to industrial gammagraphy, affecting 7 radiation workers and 19 members of the public; however, none of them were fatal. Some methods of reconstructive dosimetry have been used to estimate the radiation dose to assist in prescribing medical treatment. The type and development of cutaneous manifestations in the exposed areas of a person is the first achievable gross dose estimation. This review article presents the state-of-the-art reconstructive dosimetry methods enabling estimation of local radiation doses and provides guidelines for medical handling of the exposed individuals. The review also presents the Chilean and Brazilian radiological accident cases to highlight the importance of reconstructive dosimetry.

  17. Software tool for portal dosimetry research.

    Science.gov (United States)

    Vial, P; Hunt, P; Greer, P B; Oliver, L; Baldock, C

    2008-09-01

    This paper describes a software tool developed for research into the use of an electronic portal imaging device (EPID) to verify dose for intensity modulated radiation therapy (IMRT) beams. A portal dose image prediction (PDIP) model that predicts the EPID response to IMRT beams has been implemented into a commercially available treatment planning system (TPS). The software tool described in this work was developed to modify the TPS PDIP model by incorporating correction factors into the predicted EPID image to account for the difference in EPID response to open beam radiation and multileaf collimator (MLC) transmitted radiation. The processes performed by the software tool include; i) read the MLC file and the PDIP from the TPS, ii) calculate the fraction of beam-on time that each point in the IMRT beam is shielded by MLC leaves, iii) interpolate correction factors from look-up tables, iv) create a corrected PDIP image from the product of the original PDIP and the correction factors and write the corrected image to file, v) display, analyse, and export various image datasets. The software tool was developed using the Microsoft Visual Studio.NET framework with the C# compiler. The operation of the software tool was validated. This software provided useful tools for EPID dosimetry research, and it is being utilised and further developed in ongoing EPID dosimetry and IMRT dosimetry projects.

  18. Diagnostic radiology dosimetry: status and trends

    Energy Technology Data Exchange (ETDEWEB)

    Rivera M, T., E-mail: trivera@ipn.mx [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, 11500 Mexico D. F. (Mexico)

    2015-10-15

    Full text: Medical radiation is by far the largest man-made source of public exposure to ionizing radiation. Since 1970 the expression of protection standards shifted from a dose- to a risk-based approach, with dose limits established to yield risks to radiation workers comparable with those for workers in other safe industries. Another hand, worldwide interest in patient dose measurement was stimulated by the publication of Patient Dose Reduction in Diagnostic Radiology by the UK National Radiological Protection Board (NRPB). In response to heightened awareness of the importance of patient dose contributed by radiology procedures, there has been a general trend to effect control of patient doses by applying the principles of optimization coupled with an increase in regulatory enforcement. In this sense, thermoluminescent dosimetry (TLD) has been actively proposed in the last 3 decades thanks to their successful applications in diagnostic radiology. At the same time, it is emerged as the best radiation dosimetry method. The present work presents advantages of thermoluminescent dosimetry for X-ray beams measurements and its optimization. (Author)

  19. In vivo dosimetry in external beam radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Mijnheer, Ben [Department of Radiation Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam 1066 CX (Netherlands); Beddar, Sam [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Izewska, Joanna [Division of Human Health, International Atomic Energy Agency, Vienna 1400 (Austria); Reft, Chester [Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, Illinois 60637 (United States)

    2013-07-15

    In vivo dosimetry (IVD) is in use in external beam radiotherapy (EBRT) to detect major errors, to assess clinically relevant differences between planned and delivered dose, to record dose received by individual patients, and to fulfill legal requirements. After discussing briefly the main characteristics of the most commonly applied IVD systems, the clinical experience of IVD during EBRT will be summarized. Advancement of the traditional aspects of in vivo dosimetry as well as the development of currently available and newly emerging noninterventional technologies are required for large-scale implementation of IVD in EBRT. These new technologies include the development of electronic portal imaging devices for 2D and 3D patient dosimetry during advanced treatment techniques, such as IMRT and VMAT, and the use of IVD in proton and ion radiotherapy by measuring the decay of radiation-induced radionuclides. In the final analysis, we will show in this Vision 20/20 paper that in addition to regulatory compliance and reimbursement issues, the rationale for in vivo measurements is to provide an accurate and independent verification of the overall treatment procedure. It will enable the identification of potential errors in dose calculation, data transfer, dose delivery, patient setup, and changes in patient anatomy. It is the authors' opinion that all treatments with curative intent should be verified through in vivo dose measurements in combination with pretreatment checks.

  20. Sensitivity studies associated with dosimetry experiment interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Bourganel, S.; Soldevila, M. [CEA/DANS/DM2S/SERMA, CEA Saclay, 91191, Gif sur Yvette (France); Ferrer, A.; Gregoire, G.; Destouches, C.; Beretz, D. [CEA/DEN-CAD/DER/SPEX, CEA Cadarache, F13108, Saint Paul lez Durance (France)

    2011-07-01

    Document available in abstract form only, full text of document follows: Interpretation of reactor dosimetry experiments with C/E comparison requires precise knowledge of parameters involved in modeling. Some parameters have more weight than others on the calculated values. So, sensitivity studies should be conducted to verify the importance of these parameters. The conclusions of these studies are used to refine the experiment modeling, or to correct uncertainty calculations. The results of these sensitivity studies allow a post-irradiation analysis, which can justify the discarding of some atypical C/M values. Derived uncertainties may be improved by the sensitivity analyses. Beyond classical parameters as geometry or composition, this paper describes some specific sensitivity studies conducted for dosimetry irradiation in reactor, and presents conclusions. These studies are based on dosimeters irradiated in the EOLE reactor facility at Cadarache CEA center. Conclusions drawn from these studies are generic and can be applied to any dosimetry study. Calculations performed for these studies were realized using TRIPOLI-4 Monte Carlo code. (authors)

  1. Patient dosimetry in classical radiology;Dosimetrie patient en radiologie classique

    Energy Technology Data Exchange (ETDEWEB)

    Valero, M. [Autorite de Surete Nucleaire, 75 Paris (France); Sirinelli, D. [Tours Univ., 37 (France); Chateil, J.F. [CHU Bordeaux, 33 (France)

    2009-10-15

    The objective is to give to the participants the means to determine, by simple methods, the dose delivered to skin during a radiological examination (conventional or numerical). The message to remember is: the use of a numerical detector does not lead systematically to reduce the dose at the patient. The dose.length product is a risk indicator. It is important to compare our practices to the procedures written in the guide of procedures and to note and to send to I.R.S.N. the dosimetry data relative to the dosimetry reference levels. (N.C.)

  2. EPR of photochromic Mo3+ in SrTiO3

    NARCIS (Netherlands)

    Kool, Th.W.

    2010-01-01

    In single crystals of SrTiO_3, a paramagnetic center, characterized by S = 3/2 and hyperfine interaction with an I = 5/2 nuclear spin has been observed in the temperature range 4.2K-77K by means of EPR. The impurity center is attributed to Mo3+. No additional line splitting in the EPR spectrum due t

  3. N-player quantum games in an EPR setting

    CERN Document Server

    Chappell, James M; Abbott, Derek

    2012-01-01

    The $N$-player quantum game is analyzed in the context of an Einstein-Podolsky-Rosen (EPR) experiment. In this setting, a player's strategies are not unitary transformations as in alternate quantum game-theoretic frameworks, but a classical choice between two directions along which spin or polarization measurements are made. The players' strategies thus remain identical to their strategies in the mixed-strategy version of the classical game. In the EPR setting the quantum game reduces itself to the corresponding classical game when the shared quantum state reaches zero entanglement. We find the relations for the probability distribution for $N$-qubit GHZ and W-type states, subject to general measurement directions, from which the expressions for the mixed Nash equilibrium and the payoffs are determined. Players' payoffs are then defined with linear functions so that common two-player games can be easily extended to the $N$-player case and permit analytic expressions for the Nash equilibrium. As a specific exa...

  4. New Developments in Spin Labels for Pulsed Dipolar EPR

    Directory of Open Access Journals (Sweden)

    Alistair J. Fielding

    2014-10-01

    Full Text Available Spin labelling is a chemical technique that enables the integration of a molecule containing an unpaired electron into another framework for study. Given the need to understand the structure, dynamics, and conformational changes of biomacromolecules, spin labelling provides a relatively non-intrusive technique and has certain advantages over X-ray crystallography; which requires high quality crystals. The technique relies on the design of binding probes that target a functional group, for example, the thiol group of a cysteine residue within a protein. The unpaired electron is typically supplied through a nitroxide radical and sterically shielded to preserve stability. Pulsed electron paramagnetic resonance (EPR techniques allow small magnetic couplings to be measured (e.g., <50 MHz providing information on single label probes or the dipolar coupling between multiple labels. In particular, distances between spin labels pairs can be derived which has led to many protein/enzymes and nucleotides being studied. Here, we summarise recent examples of spin labels used for pulse EPR that serve to illustrate the contribution of chemistry to advancing discoveries in this field.

  5. SIMULACIÓN DEL ESPECTRO EPR DEL RADICAL CO2-

    Directory of Open Access Journals (Sweden)

    Eduar Enrique Carvajal Taborda

    2013-09-01

    Full Text Available La  dosimetría EPR se basa en el hecho de que las radiaciones ionizantes interaccionan con el tejido mineralizado, en este caso es esmalte dental y tejido óseo, generan los radicales CO2- estables a temperatura ambiente y de larga vida cuya concentración depende de la dosis recibida. La cuantificación de estos radicales libres se hace por EPR, cuyo espectro característico consta de dos líneas, una muy intensa y otra de menor intensidad. En este trabajo identificamos teóricamente estas dos líneas solucionando el Hamiltoniano de espín electrónico y  simulando el espectro experimental, encontramos que el espectro ERP del radical CO2- es producido por la interacción del espín del electrón desapareado con el campo magnético externo y que el radical CO2- está ubicado en una simetría local axial.

  6. Dosimetry tools and techniques for IMRT.

    Science.gov (United States)

    Low, Daniel A; Moran, Jean M; Dempsey, James F; Dong, Lei; Oldham, Mark

    2011-03-01

    Intensity modulated radiation therapy (IMRT) poses a number of challenges for properly measuring commissioning data and quality assurance (QA) radiation dose distributions. This report provides a comprehensive overview of how dosimeters, phantoms, and dose distribution analysis techniques should be used to support the commissioning and quality assurance requirements of an IMRT program. The proper applications of each dosimeter are described along with the limitations of each system. Point detectors, arrays, film, and electronic portal imagers are discussed with respect to their proper use, along with potential applications of 3D dosimetry. Regardless of the IMRT technique utilized, some situations require the use of multiple detectors for the acquisition of accurate commissioning data. The overall goal of this task group report is to provide a document that aids the physicist in the proper selection and use of the dosimetry tools available for IMRT QA and to provide a resource for physicists that describes dosimetry measurement techniques for purposes of IMRT commissioning and measurement-based characterization or verification of IMRT treatment plans. This report is not intended to provide a comprehensive review of commissioning and QA procedures for IMRT. Instead, this report focuses on the aspects of metrology, particularly the practical aspects of measurements that are unique to IMRT. The metrology of IMRT concerns the application of measurement instruments and their suitability, calibration, and quality control of measurements. Each of the dosimetry measurement tools has limitations that need to be considered when incorporating them into a commissioning process or a comprehensive QA program. For example, routine quality assurance procedures require the use of robust field dosimetry systems. These often exhibit limitations with respect to spatial resolution or energy response and need to themselves be commissioned against more established dosimeters. A chain of

  7. Cd 2+ effect on free radicals in Cladosporium cladosporioides-melanin tested by EPR spectroscopy

    Science.gov (United States)

    Matuszczyk, Magdalena; Buszman, Ewa; Pilawa, Barbara; Witoszyńska, Teresa; Wilczok, Tadeusz

    2004-08-01

    Changes in free radicals system of Cladosporium cladosporioides-melanin and model DOPA-melanin caused by diamagnetic Cd 2+ ions were studied by electron paramagnetic resonance (EPR) spectroscopy. EPR line of eumelanin was mainly found in the spectrum of Cl.cl.-melanin. Cd 2+ ions increased o-semiquinone free radicals concentration in both natural and synthetic melanins. Cd 2+ broadened EPR lines of Cl.cl.-melanin in mycelium and the ions fastened spin-lattice relaxation processes. The narrower EPR lines and slower spin-lattice relaxation were obtained for DOPA-melanin-Cd 2+ complexes than for DOPA-melanin. Pheomelanin additionally existing in Cl.cl. samples was responsible for differences between the EPR data for Cl.cl. melanin and DOPA-melanin.

  8. Alcoholic extraction enables EPR analysis to characterize radiation-induced cellulosic signals in spices.

    Science.gov (United States)

    Ahn, Jae-Jun; Sanyal, Bhaskar; Akram, Kashif; Kwon, Joong-Ho

    2014-11-19

    Different spices such as turmeric, oregano, and cinnamon were γ-irradiated at 1 and 10 kGy. The electron paramagnetic resonance (EPR) spectra of the nonirradiated samples were characterized by a single central signal (g = 2.006), the intensity of which was significantly enhanced upon irradiation. The EPR spectra of the irradiated spice samples were characterized by an additional triplet signal at g = 2.006 with a hyperfine coupling constant of 3 mT, associated with the cellulose radical. EPR analysis on various sample pretreatments in the irradiated spice samples demonstrated that the spectral features of the cellulose radical varied on the basis of the pretreatment protocol. Alcoholic extraction pretreatment produced considerable improvements of the EPR signals of the irradiated spice samples relative to the conventional oven and freeze-drying techniques. The alcoholic extraction process is therefore proposed as the most suitable sample pretreatment for unambiguous detection of irradiated spices by EPR spectroscopy.

  9. Dosimetry intercomparisons in European medical device sterilization plants

    DEFF Research Database (Denmark)

    Miller, A.; Sharpe, P.H.G.

    2000-01-01

    Dosimetry intercomparisons have been carried out involving two-thirds of all European radiation sterilization facilities. Dosimeters for the intercomparisons were supplied by two accredited calibration laboratories. The results show good agreement, and indicate overall dosimetry accuracy of the o...... of the order of +/-5% (1 sigma) for both Co-60 and electron beam plants. (C) 2000 Elsevier Science Ltd. All rights reserved....

  10. [Instrumental radiofrequency electromagnetic radiation dosimetry: general principals and modern methodology].

    Science.gov (United States)

    Perov, S Iu; Kudriashov, Iu B; Rubtsova, N B

    2012-01-01

    The modern experimental radiofrequency electromagnetic field dosimetry approach has been considered. The main principles of specific absorbed rate measurement are analyzed for electromagnetic field biological effect assessment. The general methodology of specific absorbed rate automated dosimetry system applied to establish the compliance of radiation sources with the safety standard requirements (maximum permissible levels and base restrictions) is described.

  11. Neutron dosimetry and radiation damage calculations for HFBR

    Energy Technology Data Exchange (ETDEWEB)

    Greenwood, L.R.; Ratner, R.T. [Pacific Northwest National Lab., TN (United States)

    1998-03-01

    Neutron dosimetry measurements have been conducted for various positions of the High Flux Beam Reactor (HFBR) at Brookhaven National Laboratory (BNL) in order to measure the neutron flux and energy spectra. Neutron dosimetry results and radiation damage calculations are presented for positions V10, V14, and V15.

  12. Use of the GATE Monte Carlo package for dosimetry applications

    Energy Technology Data Exchange (ETDEWEB)

    Visvikis, D. [INSERM U650, LaTIM, University Hospital Medical School, F 29609 Brest (France)]. E-mail: Visvikis.Dimitris@univ-brest.fr; Bardies, M. [INSERM U601, CHU Nantes, F 44093 Nantes (France); Chiavassa, S. [INSERM U601, CHU Nantes, F 44093 Nantes (France); Danford, C. [Department of Medical Physics, MSKCC, New York (United States); Kirov, A. [Department of Medical Physics, MSKCC, New York (United States); Lamare, F. [INSERM U650, LaTIM, University Hospital Medical School, F 29609 Brest (France); Maigne, L. [Departement de Curietherapie-Radiotherapie, Centre Jean Perrin, F 63000 Clemont-Ferrand (France); Staelens, S. [UGent-ELIS, St-Pietersnieuwstraat, 41, B 9000 Gent (Belgium); Taschereau, R. [CRUMP Institute for Molecular Imaging, UCLA, Los Angeles (United States)

    2006-12-20

    One of the roles for Monte Carlo (MC) simulation studies is in the area of dosimetry. A number of different codes dedicated to dosimetry applications are available and widely used today, such as MCNP, EGSnrc and PTRAN. However, such codes do not easily facilitate the description of complicated 3D sources or emission tomography systems and associated data flow, which may be useful in different dosimetry application domains. Such problems can be overcome by the use of specific MC codes such as GATE (GEANT4 Application to Tomographic Emission), which is based on Geant4 libraries, providing a scripting interface with a number of advantages for the simulation of SPECT and PET systems. Despite this potential, its major disadvantage is in terms of efficiency involving long execution times for applications such as dosimetry. The strong points and disadvantages of GATE in comparison to other dosimetry specific codes are discussed and illustrated in terms of accuracy, efficiency and flexibility. A number of features, such as the use of voxelised and moving sources, as well as developments such as advanced visualization tools and the development of dose estimation maps allowing GATE to be used for dosimetry applications are presented. In addition, different examples from dosimetry applications with GATE are given. Finally, future directions with respect to the use of GATE for dosimetry applications are outlined.

  13. Sandia National Laboratories Internal Dosimetry Technical Basis Manual (Rev 4)

    Energy Technology Data Exchange (ETDEWEB)

    Goke, Sarah Hayes [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Elliott, Nathan Ryan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    The Sandia National Laboratories’ Internal Dosimetry Technical Basis Manual is intended to provide extended technical discussion and justification of the internal dosimetry program at SNL. It serves to record the approach to evaluating internal doses from radiobioassay data, and where appropriate, from workplace monitoring data per the Department of Energy Internal Dosimetry Program Guide DOE G 441.1C. The discussion contained herein is directed primarily to current and future SNL internal dosimetrists. In an effort to conserve space in the TBM and avoid duplication, it contains numerous references providing an entry point into the internal dosimetry literature relevant to this program. The TBM is not intended to act as a policy or procedure statement, but will supplement the information normally found in procedures or policy documents. The internal dosimetry program outlined in this manual is intended to meet the requirements of Federal Rule 10CFR835 for monitoring the workplace and for assessing internal radiation doses to workers.

  14. Characterization by EPR of radicals in HDPE, PA6 and HDPE/PA6 blend irradiated with gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Silva, P. [Centro de Fisica, Instituto Venezolano de Investigacion Cientifica IVIC, Carretera Panamericana Km. 11, A.P. 21827, Caracas 1020-A (Venezuela); Albano, C.; Lovera, D. [Centro de Quimica, IVIC (Venezuela); Perera, R. [Departamento de Mecanica, Universidad Simon Bolivar, Caracas (Venezuela)

    2003-07-01

    Using electron paramagnetic resonance (EPR), we studied the tree radical formation in high-density Polyethylene (HDPE), polyamide (PA6) and HDPE/PA6 (80/20)blend, irradiated with integral doses (D), 0 < D < 1000 KGy, with a dose rate of irradiation in air of 6.6 KGy/h. Typical spectra indicative of the formation of allyl, alkyl and poly enyl radicals were obtained. A decay in the total number of spins per gram (C/g), when the samples are aged by a period of time of 30 days, was found, which is typical of a recombination of radicals with their environment. Additionally, a different order fit for the C/g as a function of D was obtained, which is indicative of the complex behavior of the kinetics of the decomposition. (Author)

  15. Thermodynamic basis of electron transfer in dihydroorotate dehydrogenase B from Lactococcus lactis: analysis by potentiometry, EPR spectroscopy, and ENDOR spectroscopy.

    Science.gov (United States)

    Mohsen, Al-Walid A; Rigby, Stephen E J; Jensen, Kaj Frank; Munro, Andrew W; Scrutton, Nigel S

    2004-06-01

    signal is assigned to the formation of a spin interacting state between the FMN semiquinone species and the reduced 2Fe-2S center. Reduction of DHODB using an excess of NADH or dihydroorotate produces EPR spectra that are distinct from those produced by dithionite. From potentiometric studies, the reduction of the 2Fe-2S center and the reduction of the FMN occur concomitantly. The study provides a detailed thermodynamic framework for electron transfer in this complex iron-sulfur flavoprotein.

  16. EPR and EOM studies in well samples from some Venezuelan oil fields: possible mechanisms of magnetic authigenesis

    Science.gov (United States)

    Aldana, M.; Díaz, M.; Costanzo-Alvarez, V.; Jiménez, S. M.; Sequera, P.

    2003-04-01

    In the last few years we have conducted Electron Paramagnetic Resonance (EPR) and Magnetic Susceptibility (MS) studies in drilling fines, from near-surface levels, from producer and non-producer wells. These studies were aimed at examining a possible causal relationship between magnetic contrasts and underlying hydrocarbons. In this work we have extended these studies to some new wells, trying to identify the possible origin (microbial and/or thermochemical) of the observed anomalies. Together with EPR and MS studies, quantification of extractable organic matter (EOM) has been also performed. The samples were pulverized and split into two aliquots. One aliquot was treated with chloroform in order to separate de EOM and obtain the sample without EOM and the EOM itself. The other aliquot was not solvent extracted. The EOM was quantified and EPR measurements were performed on both aliquots in order to determine the organic matter free radical concentration (OMFRC). The treatments performed allow identifying whether the OMFRC belongs to the EOM or to the total organic matter (TOM). Asphaltenes tend to be the major components in highly biodegraded crude oils. Then the presence of OMFRC belonging to the TOM or to the EOM could indicate a possible microbial or thermochemical origin, respectively, of the detected MS anomalies. We have found OMFRC and EOM anomalies only at the producer wells, in the same zone where MS anomalies, associated with the presence of spherical aggregates of magnetic minerals, were observed. For some of these wells our results indicate the solely presence of free radicals of kerogen at OMFRC anomalous level. In fact, the EOM of these wells has no EPR signal and precipitation of asphaltene in n-heptane was not observed. In other instances, free radicals of kerogen and asphaltenes and precipitation of asphaltene from the EOM in n-heptane was observed. In the former case we suggest the existence of a reducing zone where thermochemical conditions are

  17. Influence of photoexcitation on the EPR spectra of Mo5+ in Li2Zn2(MoO4)3: Ce3+,Cu2+ crystals annealed in a CO2 atmosphere

    Science.gov (United States)

    Ryadun, A. A.; Nadolinny, V. A.; Pavlyuk, A. A.; Trifonov, V. A.

    2013-04-01

    The influence of recovery annealing in a CO2 atmosphere at 700°C on the properties of Li2Zn2(MoO4)3 crystals doped with cerium and copper ions has been studied. The EPR investigation of Li2Zn2(MoO4)3 crystals annealed in a CO2 atmosphere has revealed that the annealing leads to the formation of oxygen vacancies in positions adjacent to the oxygen octahedron of lithium, M3, and the oxygen tetrahedron of molybdenum, Mo1. In this case, the charge state of molybdenum becomes Mo5+ and appears in the EPR spectra in the form of one magnetically nonequivalent position. The analysis of the angular dependence of the EPR spectrum of Mo5+ made it possible to calculate the spectral parameters g ∥ = 1.862, g ⊥ = 1.933, A ∥ = 71.8 G, and A ⊥ = 34.1 G. The cross relaxation on the hyperfine structure from the molybdenum isotope 97Mo is found in the EPR spectra. The photoexcitation of Li2Zn2(MoO4)3 crystal doped with cerium ions leads to the saturation of the EPR spectrum of Mo5+ and to the formation of the hyperfine structure from one lithium ion with a hyperfine structure constant of 14 G. For Li2Zn2(MoO4)3 crystals doped with copper ions, a very weak EPR spectrum of Mo5+ is observed in the initial crystals. As a result of the photoexcitation, an increase in the intensity of this spectrum by an order of magnitude and manifestation of the EPR spectrum of Cu2+ ions take place. It is assumed that such a behavior of the EPR spectra of molybdenum ions in Li2Zn2(MoO4)3 crystals doped with cerium and copper ions under photoexcitation is caused by different positions of the energy levels of cerium and copper ions with respect to the energy level of the molybdenum ion.

  18. Teledosimetry: Personal and Area Dosimetry Control in order to evaluate the risk in real time

    Energy Technology Data Exchange (ETDEWEB)

    Galan Montenegro, P.; Macias Jaen, J.; Bodineau Gil, C.; Sanchez Hidalgo, M.

    2004-07-01

    Telemedicine is now an essential part of Health care and so, in addition to the scientific programme in the Carlos Haya Hospital in Malaga, Physics Department is involved into a process of change about the vision as a new Health Centre of XXI Century: Knowledge Hospital, by digital architecture and digitally integrated in its world. The Integrating the Health care Enterprise is the model used in order to get a big grade of relationship between medical images and information system. This change must be done in colaboration between some Departments of our centre, because it is a multidisciplinary task. It is understood that Teledosimetry can be considered as an important part of Telemedicine in the Radiological Protection field for workers and general public. In order to get this objective, the first step since 2000 it has been to prepare the internal hospital network with personal dosimetry information. From here workers in our hospital can obtain their dosimetry information data in more than 300 computers and since 2003, from home too. For access, each one of all have got an user identification and a password and so it can be guaranteed the privacy. We transform dose data reported by CND (Dosimetry National Center) in a big and visible database in PHP4 and Javascript format. This process is marked of problems about all due to the big manipulated information. Our intention is to make a better and friendly control, customisable and in real-time of the information dosimetry by a modular monitoring system of electronic dosimeters by the web. These radiation detectors would be located in representatives places. (Author)

  19. Neutron dosimetry for low dose rate Cf-252 AT sources and adherence to recent clinical dosimetry protocol for brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, M.J.; Wierzbicki, J.G.; Van den Heuvel, F. [Wayne State Univ., Detroit, MI (United States). Dept. of Radiation Oncology; Martin, R.C. [Oak Ridge National Lab., TN (United States). Chemical Technology Div.

    1997-12-01

    In 1995, the American Association of Physicists in Medicine Task Group 43 (AAPM TG-43) published a protocol obsoleting all mixed-field radiation dosimetry for Cf-252. Recommendations for a new brachytherapy dosimetry formalism made by this Task Group favor quantification of source strength in terms of air kerma rather than apparent Curies or other radiation units. Additionally, representation of this dosimetry data in terms of radial dose functions, anisotropy functions, geometric factors, and dose rate constants are in an angular and radial (spherical) coordinate system as recommended, rather than the along-away dosimetry data (Cartesian coordinate system) currently available. This paper presents the initial results of calculated neutron dosimetry in a water phantom for a Cf-252 applicator tube (AT) type medical source soon available from Oak Ridge National Laboratory (ORNL).

  20. Dosimetry applications in GATE Monte Carlo toolkit.

    Science.gov (United States)

    Papadimitroulas, Panagiotis

    2017-02-21

    Monte Carlo (MC) simulations are a well-established method for studying physical processes in medical physics. The purpose of this review is to present GATE dosimetry applications on diagnostic and therapeutic simulated protocols. There is a significant need for accurate quantification of the absorbed dose in several specific applications such as preclinical and pediatric studies. GATE is an open-source MC toolkit for simulating imaging, radiotherapy (RT) and dosimetry applications in a user-friendly environment, which is well validated and widely accepted by the scientific community. In RT applications, during treatment planning, it is essential to accurately assess the deposited energy and the absorbed dose per tissue/organ of interest, as well as the local statistical uncertainty. Several types of realistic dosimetric applications are described including: molecular imaging, radio-immunotherapy, radiotherapy and brachytherapy. GATE has been efficiently used in several applications, such as Dose Point Kernels, S-values, Brachytherapy parameters, and has been compared against various MC codes which are considered as standard tools for decades. Furthermore, the presented studies show reliable modeling of particle beams when comparing experimental with simulated data. Examples of different dosimetric protocols are reported for individualized dosimetry and simulations combining imaging and therapy dose monitoring, with the use of modern computational phantoms. Personalization of medical protocols can be achieved by combining GATE MC simulations with anthropomorphic computational models and clinical anatomical data. This is a review study, covering several dosimetric applications of GATE, and the different tools used for modeling realistic clinical acquisitions with accurate dose assessment. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  1. In vivo light dosimetry for pleural PDT

    Science.gov (United States)

    Dimofte, Andreea; Zhu, Timothy C.; Finlay, Jarod C.; Culligan, Melissa; Edmonds, Christine E.; Friedberg, Joseph S.; Cengel, Keith; Hahn, Stephen M.

    2009-02-01

    In-vivo light Dosimetry for patients undergoing photodynamic therapy (PDT) is one of the important dosimetry quantities critical for predicting PDT outcome. This study examines the light fluence (rate) delivered to patients undergoing pleural PDT as a function of treatment time, treatment volume and surface area, and its accuracy as a function of the calibration accuracies of each isotropic detector and the calibration integrating sphere. The patients studied here were enrolled in Phase II clinical trial of Photofrin-mediated PDT for the treatment of non-small cell lung cancer with pleural effusion. The ages of the patients studied varied from 34 to 69 year old. All patients were administered 2mg per kg body weight Photoprin 24 hours before the surgery. Patients undergoing photodynamic therapy (PDT) are treated with laser light with a light fluence of 60 J/cm^2 at 630nm. Fluence rate (mW/cm^2) and cumulative fluence (J/cm^2) was monitored at 7 different sites during the entire light treatment delivery. Isotropic detectors were used for in-vivo light dosimetry. The anisotropy of each isotropic detector was found to be within 30%. The mean fluence rate delivery varied from 37.84 to 94.05 mW/cm^2 and treatment time varied from 1762 to 5232s. We have established a correlation between the treatment time and the treatment volume. The results are discussed using an integrating sphere theory and the measured tissue optical properties. The result can be used as a clinical guideline for future pleural PDT treatment.

  2. EPR = ER and Scattering Amplitude as Entanglement Entropy Change

    CERN Document Server

    Seki, Shigenori

    2014-01-01

    Alday and Maldacena have found an exact minimal surface of open string world-sheet describing a gluon scattering. We study the causal structure of that minimal surface in AdS of position space, and find a world-sheet wormhole parametrized by Mandelstam variables. If we figure a gluon as an open string in AdS, the ribbon connecting the two strings always pass the world-sheet wormhole, demonstrating the EPR = ER for gluon scattering. Since entanglement is caused by an interaction, one can ask what is the relation between entanglement entropy and the scattering amplitude. We propose an answer by generalizing the holographic entanglement entropy (EE) of Ryu-Takayanagi to the case where two regions are divided in space-time and interpret the result as the change of EE.

  3. Effect of microwave power on EPR spectra of natural and synthetic dental biocompatible materials

    Directory of Open Access Journals (Sweden)

    Adamczyk Jakub

    2015-07-01

    Full Text Available Paramagnetic centers in the two exemplary synthetic and natural dental biocompatible materials applied in implantology were examined by the use of an X-band (9.3 GHz electron paramagnetic resonance (EPR spectroscopy. The EPR spectra were measured in the range of microwave power 2.2–70 mW. The aims of this work were to compare paramagnetic centers concentrations in different dental biocompatible materials and to determine the effect of microwave power on parameters of their EPR spectra. It is the very first and innovatory examination of paramagnetic centers in these materials. It was pointed out that paramagnetic centers existed in both natural (~1018 spin/g and synthetic (~1019 spin/g dental biocompatible materials, but the lower free radical concentration characterized the natural sample. Continuous microwave saturation of EPR spectra indicated that faster spin-lattice relaxation processes existed in synthetic dental biocompatible materials than in natural material. Linewidths (ΔBpp of the EPR spectra of the natural dental material slightly increased for the higher microwave powers. Such effect was not observed for the synthetic material. The broad EPR lines (ΔBpp: 2.4 mT, 3.9 mT, were measured for the natural and synthetic dental materials, respectively. Probably strong dipolar interactions between paramagnetic centers in the studied samples may be responsible for their line broadening. EPR spectroscopy is the useful experimental method in the examination of paramagnetic centers in dental biocompatible materials.

  4. Nuclear spin-lattice relaxation in nitroxide spin-label EPR

    DEFF Research Database (Denmark)

    Marsh, Derek

    2016-01-01

    Nuclear relaxation is a sensitive monitor of rotational dynamics in spin-label EPR. It also contributes competing saturation transfer pathways in T1-exchange spectroscopy, and the determination of paramagnetic relaxation enhancement in site-directed spin labelling. A survey shows that the definit......Nuclear relaxation is a sensitive monitor of rotational dynamics in spin-label EPR. It also contributes competing saturation transfer pathways in T1-exchange spectroscopy, and the determination of paramagnetic relaxation enhancement in site-directed spin labelling. A survey shows...... that the definition of nitrogen nuclear relaxation rate Wn commonly used in the CW-EPR literature for 14N-nitroxyl spin labels is inconsistent with that currently adopted in time-resolved EPR measurements of saturation recovery. Redefinition of the normalised 14N spin-lattice relaxation rate, b = Wn/(2We), preserves...... the expressions used for CW-EPR, whilst rendering them consistent with expressions for saturation recovery rates in pulsed EPR. Furthermore, values routinely quoted for nuclear relaxation times that are deduced from EPR spectral diffusion rates in 14N-nitroxyl spin labels do not accord with conventional analysis...

  5. Active cancellation - A means to zero dead-time pulse EPR

    Science.gov (United States)

    Franck, John M.; Barnes, Ryan P.; Keller, Timothy J.; Kaufmann, Thomas; Han, Songi

    2015-12-01

    The necessary resonator employed in pulse electron paramagnetic resonance (EPR) rings after the excitation pulse and creates a finite detector dead-time that ultimately prevents the detection of signal from fast relaxing spin systems, hindering the application of pulse EPR to room temperature measurements of interesting chemical or biological systems. We employ a recently available high bandwidth arbitrary waveform generator (AWG) to produce a cancellation pulse that precisely destructively interferes with the resonant cavity ring-down. We find that we can faithfully detect EPR signal at all times immediately after, as well as during, the excitation pulse. This is a proof of concept study showcasing the capability of AWG pulses to precisely cancel out the resonator ring-down, and allow for the detection of EPR signal during the pulse itself, as well as the dead-time of the resonator. However, the applicability of this approach to conventional EPR experiments is not immediate, as it hinges on either (1) the availability of low-noise microwave sources and amplifiers to produce the necessary power for pulse EPR experiment or (2) the availability of very high conversion factor micro coil resonators that allow for pulse EPR experiments at modest microwave power.

  6. Nuclear spin-lattice relaxation in nitroxide spin-label EPR

    Science.gov (United States)

    Marsh, Derek

    2016-11-01

    Nuclear relaxation is a sensitive monitor of rotational dynamics in spin-label EPR. It also contributes competing saturation transfer pathways in T1-exchange spectroscopy, and the determination of paramagnetic relaxation enhancement in site-directed spin labelling. A survey shows that the definition of nitrogen nuclear relaxation rate Wn commonly used in the CW-EPR literature for 14N-nitroxyl spin labels is inconsistent with that currently adopted in time-resolved EPR measurements of saturation recovery. Redefinition of the normalised 14N spin-lattice relaxation rate, b = Wn/(2We), preserves the expressions used for CW-EPR, whilst rendering them consistent with expressions for saturation recovery rates in pulsed EPR. Furthermore, values routinely quoted for nuclear relaxation times that are deduced from EPR spectral diffusion rates in 14N-nitroxyl spin labels do not accord with conventional analysis of spin-lattice relaxation in this three-level system. Expressions for CW-saturation EPR with the revised definitions are summarised. Data on nitrogen nuclear spin-lattice relaxation times are compiled according to the three-level scheme for 14N-relaxation: T1n = 1/Wn. Results are compared and contrasted with those for the two-level 15N-nitroxide system.

  7. Neutron spectrometry and dosimetry with ANNs

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R.; Hernandez D, V. M. [Unidad Academica de Estudios Nucleares, Universidad Autonoma de Zacatecas, Cipres 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Gallego, E.; Lorente, A. [Departamento de Ingenieria Nuclear, Universidad Politecnica de Madrid, Jose Gutierrez Abascal 2, 28006 Madrid (Spain)], e-mail: fermineutron@yahoo.com

    2009-10-15

    Artificial neural networks technology has been applied to unfold the neutron spectra and to calculate the effective dose, the ambient equivalent dose, and the personal dose equivalent for {sup 252}Cf and {sup 241}AmBe neutron sources. A Bonner sphere spectrometry with a {sup 6}LiI(Eu) scintillator was utilized to measure the count rates of the spheres that were utilized as input in two artificial neural networks, one for spectrometry and another for dosimetry. Spectra and the ambient dose equivalent were also obtained with BUNKIUT code and the UTA4 response matrix. With both procedures spectra and ambient dose equivalent agrees in less than 10%. (author)

  8. Secondary standard dosimetry laboratory at INFLPR

    Energy Technology Data Exchange (ETDEWEB)

    Scarlat, F.; Minea, R.; Scarisoreanu, A.; Badita, E.; Sima, E.; Dumitrascu, M.; Stancu, E.; Vancea, C., E-mail: scarlat.f@gmail.com [National Institute for Laser, Plasma and Radiation Physics - INFLPR, Bucharest (Romania)

    2011-07-01

    National Institute for Laser, Plasma and Radiation Physics (INFLPR) has constructed a High Energy Secondary Standard Dosimetry Laboratory SSDL-STARDOOR - for performing dosimetric calibrations according to ISO IEC SR/EN 17025:2005 standards. This is outfitted with UNIDOS Secondary Standard Dosimeter from PTW (Freiburg Physikalisch-Technische Werksttaten) calibrated at the PTB-Braunschweig (German Federal Institute of Physics and Metrology). A radiation beam of the quality of Q used by our laboratory as calibration source are provided by INFLPR 7 MeV electron beam linear accelerator mounted in our facility. (author)

  9. Eurados trial performance test for photon dosimetry

    DEFF Research Database (Denmark)

    Stadtmann, H.; Bordy, J.M.; Ambrosi, P.

    2001-01-01

    Within the framework of the EURADOS Action entitled Harmonisation and Dosimetric Quality Assurance in Individual Monitoring for External Radiation, trial performance tests for whole-body and extremity personal dosemeters were carried out. Photon, beta and neutron dosemeters were considered....... This paper summarises the results of the whole-body photon dosemeter test. Twenty-six dosimetry services from all EU Member States and Switzerland participated. Twelve different radiation fields were used to simulate various workplace irradiation fields. Dose values from 0.4 mSv to 80 mSv were chosen. From...

  10. Proton minibeam radiation therapy: Experimental dosimetry evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Peucelle, C.; Martínez-Rovira, I.; Prezado, Y., E-mail: prezado@imnc.in2p3.fr [IMNC-UMR 8165, CNRS, Paris 7 and Paris 11 Universities, 15 rue Georges Clemenceau, Orsay Cedex 91406 (France); Nauraye, C.; Patriarca, A.; Hierso, E.; Fournier-Bidoz, N. [Institut Curie - Centre de Protonthérapie d’Orsay, Campus Universitaire, Bât. 101, Orsay 91898 (France)

    2015-12-15

    Purpose: Proton minibeam radiation therapy (pMBRT) is a new radiotherapy (RT) approach that allies the inherent physical advantages of protons with the normal tissue preservation observed when irradiated with submillimetric spatially fractionated beams. This dosimetry work aims at demonstrating the feasibility of the technical implementation of pMBRT. This has been performed at the Institut Curie - Proton Therapy Center in Orsay. Methods: Proton minibeams (400 and 700 μm-width) were generated by means of a brass multislit collimator. Center-to-center distances between consecutive beams of 3200 and 3500 μm, respectively, were employed. The (passive scattered) beam energy was 100 MeV corresponding to a range of 7.7 cm water equivalent. Absolute dosimetry was performed with a thimble ionization chamber (IBA CC13) in a water tank. Relative dosimetry was carried out irradiating radiochromic films interspersed in a IBA RW3 slab phantom. Depth dose curves and lateral profiles at different depths were evaluated. Peak-to-valley dose ratios (PVDR), beam widths, and output factors were also assessed as a function of depth. Results: A pattern of peaks and valleys was maintained in the transverse direction with PVDR values decreasing as a function of depth until 6.7 cm. From that depth, the transverse dose profiles became homogeneous due to multiple Coulomb scattering. Peak-to-valley dose ratio values extended from 8.2 ± 0.5 at the phantom surface to 1.08 ± 0.06 at the Bragg peak. This was the first time that dosimetry in such small proton field sizes was performed. Despite the challenge, a complete set of dosimetric data needed to guide the first biological experiments was achieved. Conclusions: pMBRT is a novel strategy in order to reduce the side effects of RT. This works provides the experimental proof of concept of this new RT method: clinical proton beams might allow depositing a (high) uniform dose in a brain tumor located in the center of the brain (7.5 cm depth

  11. Characterization of brazilian wollastonite for radiation dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Souza, D.N. [Departamento de Fisica, Universidade Federal de Sergipe, Sao Cristovao/SE (Brazil); Melo, A.P.; Gazano, V.S.O.; Caldas, L.V.E. [Instituto de Pesquisas Energeticas e Nucleares, Comissao Nacional de Energia Nuclear, Sao Paulo (Brazil)]. e-mail: dnsouza@fisca.ufs.br

    2006-07-01

    In these work preliminary results of the characterization analyses of Brazilian Wollastonite for radiation dosimetry are presented. Wollastonite is a silicate of calcium, Ca(SiO{sub 3}), and it was acquired in the form of rude mineral with Andradite inclusions. The sample was cleaned and prepared for obtained selected grains of Wollastonite. The analyses of chemical and mineralogical compositions were obtained using the neutron activation and X-ray powder diffraction techniques. The thermoluminescent (TL) glow curve of the material shows a prominent peak at about 200 C. TL emission spectra, and photoinduced emission spectra were also obtained. (Author)

  12. Chain Dynamics, Relaxation Times, and Conductivities of Bithiophene--Acene Copolymers Measured Using High Frequency Saturation Transfer EPR.

    Science.gov (United States)

    Fraind, Alicia M; Ryzhkov, Lev R; Tovar, John D

    2016-02-11

    We present a study to probe the formation of localized aromatic sextets and their effects on the charge transport properties in polymers with acene cores. Bithiophene-acene copolymers containing benzene, naphthalene, or anthracene as acene cores were synthesized using Yamamoto polymerization. Drop-casted polymer films were chemically doped and analyzed using high frequency saturation transfer EPR (HF ST-EPR), a method which has proven useful in the study of conducting polymers. The spin-spin and spin-lattice relaxation times were determined for these polymers at low temperatures (4 to 20 K) and used to obtain inter- and intrachain spin diffusion rates and conductivities. Similar interchain spin diffusion rates were seen across all polymer systems; however, anthracene containing polymer poly(hexylTTATT) was found to have the largest intrachain spin diffusion rate. The poly(hexylTTATT) intrachain spin diffusion rate may be artificially high if the anthracene ring restricts the diffusion of spin to the hexylated quaterthiophene segment in poly(hexylTTATT) whereas the spins diffuse through the acene cores in the benzene and naphthalene derivatives. Alternatively, as both the spin diffusion rates and conductivities vary unpredictably with temperature, it is possible that the π-electron localization previously seen in the anthracene core could be relieved at lower temperatures.

  13. Electrochemical, UV--visible and EPR studies on nitrofurantoin: nitro radical anion generation and its interaction with glutathione.

    Science.gov (United States)

    Núñez-Vergara, L J; Sturm, J C; Olea-Azar, C; Navarrete-Encina, P; Bollo, S; Squella, J A

    2000-05-01

    This paper deals with the reactivity of the nitro radical anion electrochemically generated from nitrofurantoin with glutathione. Cyclic voltammetry (CV) and controlled potential electrolysis were used to generate the nitro radical anion in situ and in bulk solution, respectively and cyclic voltammetry, UV--Visible and EPR spectroscopy were used to characterize the electrochemically formed radical and to study its interaction with GSH. By cyclic voltammetry on a hanging mercury drop electrode, the formation of the nitro radical anion was possible in mixed media (0.015M aqueous citrate/DMF, 40/60, pH 9) and in aprotic media. A second order decay of the radicals was determined, with a k2 value of 201 and 111 M(-1) s(-1), respectively. Controlled potential electrolysis generated the radical and its detection by cyclic voltammetry, UV--Visible and EPR spectroscopy was possible. When glutathione (GSH) was added to the solution, an unambiguous decay in the signals corresponding to a nitro radical anion were observed and using a spin trapping technique, a thiyl radical was detected. Electrochemical and spectroscopic data indicated that it is possible to generate the nitro radical anion from nitrofurantoin in solution and that GSH scavenged this reactive species, in contrast with other authors, which previously reported no interaction between them.

  14. Post-processing of EPR spectrum from dosimetric substances through filtering of Discrete Fourier Transform; Pos-processamento de espectros de RPE de substancias dosimetricas por filtragem da transformada discreta de Fourier

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Fabio P.B.; Bevilacqua, Joyce S., E-mail: fpbvieira@gmail.com, E-mail: joyce.bevilacqua@gmail.com [Universidade de Sao Paulo (IME/USP), Sao Paulo, SP (Brazil). Instituto de Matematica e Estatistica; Rodrigues Junior, Orlando, E-mail: rodrijr@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2014-07-01

    The use of electron paramagnetic resonance spectrometers - EPR - in radiation dosimetry is known for more than four decades. It is an important tool in the retrospective determination of doses absorbed. To estimate the dose absorbed by the sample, it is necessary to know the amplitude of the peak to peak signature of the substance in its EPR spectrum. This information can be compromised by the presence of spurious information: noise - of random and low intensity nature; and the behavior of the baseline - coming from the coupling between the resonator tube and the sample analyzed. Due to the intrinsic characteristics of the three main components of the signal, i.e. signature, noise, and baseline - the analysis in the frequency domain allows, through post-processing techniques to filter spurious information. In this work, an algorithm that retrieves the signature of a substance has been implemented. The Discrete Fourier Transform is applied to the signal and without user intervention, the noise is filtered. From the filtered signal, recovers the signature by Inverse Discrete Fourier Transform. The peak to peak amplitude, and the absorbed dose is calculated with an error of less than 1% for signals wherein the base line is linearized. Some more general cases are under investigation and with little user intervention, you can get the same error.

  15. Copper-phthalocyanine encapsulated into zeolite-Y with high Si/Al: An EPR study

    Science.gov (United States)

    Yahiro, Hidenori; Kimoto, Kunihiro; Yamaura, Hiroyuki; Komaguchi, Kenji; Lund, Anders

    2005-10-01

    Copper (II) phthalocyanine (CuPc) molecules encapsulated into zeolite-Y with Si/Al ratios of 2.7 and 410 were prepared by an in situ synthesis and characterized by UV-Vis and electron paramagnetic resonance (EPR) spectroscopies. Resolved Cu-hyperfine and N-superhyperfine structures were observed in the EPR spectrum of CuPc encapsulated into zeolite-Y with a high Si/Al ratio. UV-Vis and EPR studies as well as theoretical calculations suggest that the encapsulated CuPc molecule was distorted in zeolite-Y with keeping of the square-planar symmetry around the center copper (II) ion.

  16. Growth and EPR properties of ErVO4 single crystals

    Directory of Open Access Journals (Sweden)

    Leniec Grzegorz

    2015-07-01

    Full Text Available Single crystals of ErVO4 were grown by the Czochralski method under ambient pressure in a nitrogen atmosphere. Obtained crystals were transparent with strong pink coloring. Electron paramagnetic resonance (EPR spectra were recorded as a function of the applied magnetic field. Temperature and angular dependences of the EPR spectra of the samples in the 3–300 K temperature range were analyzed applying both Lorentzian––Gauss approximation for diluted medium and Dyson for dense magnetic medium. EPR-NMR program was done to find local symmetry and spin Hamiltonian parameters of erbium ions.

  17. EPR statistical mixture of correlated states with fractional brownian process induced by third party interaction

    CERN Document Server

    Tamburini, F; Bianchini, A

    1999-01-01

    A time-correlated EPR pairs protocol is analized, based on detection of fractal correlated signals into a statistical mixture of EPR correlated pairs: an approximated alpha-Fractional Brownian Motion (FBM) is induced on the group of EPR pairs (e.g. by sender-third party eavesdropper-like interactions as in Ekert quantum cryptography), to be detected by the receiver using a non - orthogonal wavelet filter, able to characterize the FBM from a noisy enviroment by formalizing a nonlinear optimization problem for the FBM alpha-characteristic parameter extimation.

  18. EPR investigation of some desiccated Ascomycota and Basidiomycota gamma-irradiated mushrooms

    Energy Technology Data Exchange (ETDEWEB)

    Bercu, V., E-mail: vbercu@gmail.co [University of Bucharest, Department of Atomic and Nuclear Physics, P.O. Box MG-11, 077125 Magurele (Ilfov) (Romania); Negut, C.D., E-mail: dnegut@nipne.r [University of Bucharest, Department of Atomic and Nuclear Physics, P.O. Box MG-11, 077125 Magurele (Ilfov) (Romania); Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O. Box MG-6, 077125 Magurele (Ilfov) (Romania); Duliu, O.G., E-mail: duliu@b.astral.r [University of Bucharest, Department of Atomic and Nuclear Physics, P.O. Box MG-11, 077125 Magurele (Ilfov) (Romania)

    2010-12-15

    The suitability of the EPR spectroscopy for detection of {gamma}-irradiation in five species of dried mushroom, currently used in gastronomy: yellow morel-Morchella esculenta, (L.) Pers. (Phylum Ascomycota), button mushroom-Agaricus bisporus (J.E.Lange), Agaricus haemorrhoidarius Fr., golden chantarelle-Cantharellus cibarius Fr., as well as oyster mushroom-Pleurotus ostreatus (Jacq. ex Fr.) (Phylum Basidiomycota) is presented and discussed. Although after irradiation at doses up to 11 kGy, all specimens presented well defined EPR spectra, only A. bisporus EPR signal was enough stable to make detection possible after 18 months.

  19. EPR investigation of some desiccated Ascomycota and Basidiomycota gamma-irradiated mushrooms

    Science.gov (United States)

    Bercu, V.; Negut, C. D.; Duliu, O. G.

    2010-12-01

    The suitability of the EPR spectroscopy for detection of γ-irradiation in five species of dried mushroom, currently used in gastronomy: yellow morel— Morchella esculenta, (L.) Pers. (Phylum Ascomycota), button mushroom— Agaricus bisporus (J.E.Lange), Agaricus haemorrhoidarius Fr., golden chantarelle— Cantharellus cibarius Fr., as well as oyster mushroom— Pleurotus ostreatus (Jacq. ex Fr.) (Phylum Basidiomycota) is presented and discussed. Although after irradiation at doses up to 11 kGy, all specimens presented well defined EPR spectra, only A. bisporus EPR signal was enough stable to make detection possible after 18 months.

  20. EPR as an analytical tool in assessing the mineral nutrients and irradiated food products-vegetables

    Science.gov (United States)

    Prasuna, C. P. Lakshmi; Chakradhar, R. P. S.; Rao, J. L.; Gopal, N. O.

    2008-12-01

    EPR spectral investigations of some commonly available vegetables in south India, which are of global importance like Daucus carota (carrot), Cyamopsis tetragonoloba (cluster beans), Coccinia indica (little gourd) and Beta vulgaris (beet root) have been carried out. In all the vegetable samples a free radical corresponding to cellulose radical is observed. Almost all the samples under investigation exhibit Mn ions in different oxidation states. The temperature variation EPR studies are done and are discussed in view of the paramagnetic oxidation states. The radiation-induced defects have also been assessed by using the EPR spectra of such irradiated food products.

  1. Dosimetry of ionising radiation in modern radiation oncology

    Science.gov (United States)

    Kron, Tomas; Lehmann, Joerg; Greer, Peter B.

    2016-07-01

    Dosimetry of ionising radiation is a well-established and mature branch of physical sciences with many applications in medicine and biology. In particular radiotherapy relies on dosimetry for optimisation of cancer treatment and avoidance of severe toxicity for patients. Several novel developments in radiotherapy have introduced new challenges for dosimetry with small and dynamically changing radiation fields being central to many of these applications such as stereotactic ablative body radiotherapy and intensity modulated radiation therapy. There is also an increasing awareness of low doses given to structures not in the target region and the associated risk of secondary cancer induction. Here accurate dosimetry is important not only for treatment optimisation but also for the generation of data that can inform radiation protection approaches in the future. The article introduces some of the challenges and highlights the interdependence of dosimetric calculations and measurements. Dosimetric concepts are explored in the context of six application fields: reference dosimetry, small fields, low dose out of field, in vivo dosimetry, brachytherapy and auditing of radiotherapy practice. Recent developments of dosimeters that can be used for these purposes are discussed using spatial resolution and number of dimensions for measurement as sorting criteria. While dosimetry is ever evolving to address the needs of advancing applications of radiation in medicine two fundamental issues remain: the accuracy of the measurement from a scientific perspective and the importance to link the measurement to a clinically relevant question. This review aims to provide an update on both of these.

  2. Photodynamic action of C-phycocyanins obtained from marine and fresh water cyanobacterial cultures: a comparative study using EPR spin trapping technique.

    Science.gov (United States)

    Paul, Bibbin Tom; Patel, Anamika; Selvam, Govindan Sadasivam; Mishra, Sandhya; Ghosh, Pushpita Kumar; Murugesan, Ramachandran

    2006-08-01

    C-phycocyanins, major biliproteins of blue green algae (cyanobacteria), widely used as colourants in food and cosmetics are known for their antioxidant as well as therapeutic potential. Recent claims indicating phycobiliproteins exert stronger photodynamic action on tumor cells than clinically approved hematoporphyrin derivatives motivate us to investigate the photodynamic action of two newly isolated C-phycocyanins from Phormidium [PHR] and Lyngbya [LY] spp, respectively in comparison with known C-phycocyanin from Spirulina sp. [SPI]. Photolysis of air saturated solutions of PHR, LY and SPI in the presence of 2,2,6,6-Tetramethyl piperidinol (TEMPL) generated three line EPR spectrum characteristic of 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxyl (TEMPOL). The increase in intensity of the EPR spectrum with time of irradiation and decrease in intensity, in the presence of 1O2 quencher DABCO confirm the formation of 1O2. Photoirradiation in the presence of spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) generated EPR signal characteristic of O2(-) adduct. Efficiency of 1O2 generation is of the order LY > PHR> SPI. The yield of reactive oxygen species (ROS) generation is found to be 1O2>O2(-) indicating type II mechanism to be the prominent pathway for photosensitation by phycocyanins.

  3. Insights into the mechanism of X-ray-induced disulfide-bond cleavage in lysozyme crystals based on EPR, optical absorption and X-ray diffraction studies

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, Kristin A. [Hauptman–Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14086 (United States); Black, Paul J.; Mercer, Kermit R. [University of Rochester Medical Center, Rochester, NY 14642 (United States); Garman, Elspeth F. [University of Oxford, South Parks Road, Oxford, Oxfordshire OX1 3QU (United Kingdom); Owen, Robin L. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Snell, Edward H., E-mail: esnell@hwi.buffalo.edu [Hauptman–Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14086 (United States); SUNY Buffalo Medical School, 700 Ellicott Street, Buffalo, NY 14203 (United States); Bernhard, William A. [University of Rochester Medical Center, Rochester, NY 14642 (United States); Hauptman–Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14086 (United States)

    2013-12-01

    Electron paramagnetic resonance (EPR) and online UV–visible absorption microspectrophotometry with X-ray crystallography have been used in a complementary manner to follow X-ray-induced disulfide-bond cleavage, to confirm a multi-track radiation-damage process and to develop a model of that process. Electron paramagnetic resonance (EPR) and online UV–visible absorption microspectrophotometry with X-ray crystallography have been used in a complementary manner to follow X-ray-induced disulfide-bond cleavage. Online UV–visible spectroscopy showed that upon X-irradiation, disulfide radicalization appeared to saturate at an absorbed dose of approximately 0.5–0.8 MGy, in contrast to the saturating dose of ∼0.2 MGy observed using EPR at much lower dose rates. The observations suggest that a multi-track model involving product formation owing to the interaction of two separate tracks is a valid model for radiation damage in protein crystals. The saturation levels are remarkably consistent given the widely different experimental parameters and the range of total absorbed doses studied. The results indicate that even at the lowest doses used for structural investigations disulfide bonds are already radicalized. Multi-track considerations offer the first step in a comprehensive model of radiation damage that could potentially lead to a combined computational and experimental approach to identifying when damage is likely to be present, to quantitate it and to provide the ability to recover the native unperturbed structure.

  4. Monte Carlo simulations for heavy ion dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Geithner, O.

    2006-07-26

    Water-to-air stopping power ratio (s{sub w,air}) calculations for the ionization chamber dosimetry of clinically relevant ion beams with initial energies from 50 to 450 MeV/u have been performed using the Monte Carlo technique. To simulate the transport of a particle in water the computer code SHIELD-HIT v2 was used which is a substantially modified version of its predecessor SHIELD-HIT v1. The code was partially rewritten, replacing formerly used single precision variables with double precision variables. The lowest particle transport specific energy was decreased from 1 MeV/u down to 10 keV/u by modifying the Bethe- Bloch formula, thus widening its range for medical dosimetry applications. Optional MSTAR and ICRU-73 stopping power data were included. The fragmentation model was verified using all available experimental data and some parameters were adjusted. The present code version shows excellent agreement with experimental data. Additional to the calculations of stopping power ratios, s{sub w,air}, the influence of fragments and I-values on s{sub w,air} for carbon ion beams was investigated. The value of s{sub w,air} deviates as much as 2.3% at the Bragg peak from the recommended by TRS-398 constant value of 1.130 for an energy of 50 MeV/u. (orig.)

  5. Dosimetry of radium-223 and progeny

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, D.R. [Pacific Northwest National Lab., Richland, WA (United States); Sgouros, G. [Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

    1999-01-01

    Radium-223 is a short-lived (11.4 d) alpha emitter with potential applications in radioimmunotherapy of cancer. Radium-223 can be complexed and linked to protein delivery molecules for specific tumor-cell targeting. It decays through a cascade of short-lived alpha- and beta-emitting daughters with emission of about 28 MeV of energy through complete decay. The first three alpha particles are essentially instantaneous. Photons associated with Ra-223 and progeny provide the means for tumor and normal-organ imaging and dosimetry. Two beta particles provide additional therapeutic value. Radium-223 may be produced economically and in sufficient amounts for widescale application. Many aspects of the chemistry of carrier-free isotope preparation, complexation, and linkage to the antibody have been developed and are being tested. The radiation dosimetry of a Ra-223-labeled antibody shows favorable tumor to normal tissue dose ratios for therapy. The 11.4-d half-life of Ra-223 allows sufficient time for immunoconjugate preparation, administration, and tumor localization by carrier antibodies before significant radiological decay takes place. If 0.01 percent of a 37 MBq (1 mCi) injection deposits in a one gram tumor mass, and if the activity is retained with a typical effective half-time (75 h), the absorbed dose will be 163 mGy MBq{sup {minus}1} (600 rad mCi{sup {minus}1}) administered. 49 refs., 5 figs., 2 tabs.

  6. DRDC Ottawa working standard for biological dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Segura, T.M.; Prud' homme-Lalonde, L. [Defence Research and Development Canada, Ottawa, Ontario (Canada); Thorleifson, E. [Health Canada, Gatineau, Quebec (Canada); Lachapelle, S.; Mullins, D. [JERA Consulting (Canada); Qutob, S. [Health Canada, Gatineau, Quebec (Canada); Wilkinson, D.

    2005-07-15

    This Standard provides quality assurance, quality control, and evaluation of the performance criteria for the purpose of accreditation of the Radiation Biology laboratory at Defence Research and Development Canada - Ottawa (DRDC Ottawa) using biological dosimetry to predict radiation exposure doses. The International Standard (ISO 19238) and the International Atomic Energy Association (IAEA) Technical Report Series No. 405 are used as guiding documents in preparation of this working document specific to the DRDC Ottawa Radiation Biology Laboratory. This Standard addresses: 1. The confidentiality of personal information, for the customer and the service laboratory; 2. The laboratory safety requirements; 3. The calibration sources and calibration dose ranges useful for establishing the reference dose-effect curves allowing the dose estimation from chromosome aberration frequency, and the minimum detection levels; 4. Transportation criteria for shipping of test samples to the laboratory; 5. Preparation of samples for analysis; 6. The scoring procedure for unstable chromosome aberrations used for biological dosimetry; 7. The criteria for converting a measured aberration frequency into an estimate of absorbed dose; 8. The reporting of results; 9. The quality assurance and quality control plan for the laboratory; and 10. Informative annexes containing examples of a questionnaire, instructions for customers, a data sheet for recording aberrations, a sample report and other supportive documents. (author)

  7. Dosimetry methods in boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-15

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

  8. Hanford External Dosimetry Technical Basis Manual PNL-MA-842

    Energy Technology Data Exchange (ETDEWEB)

    Rathbone, Bruce A.

    2009-08-28

    The Hanford External Dosimetry Technical Basis Manual PNL-MA-842 documents the design and implementation of the external dosimetry system used at Hanford. The manual describes the dosimeter design, processing protocols, dose calculation methodology, radiation fields encountered, dosimeter response characteristics, limitations of dosimeter design under field conditions, and makes recommendations for effective use of the dosimeters in the field. The manual describes the technical basis for the dosimetry system in a manner intended to help ensure defensibility of the dose of record at Hanford and to demonstrate compliance with 10 CFR 835, DOELAP, DOE-RL, ORP, PNSO, and Hanford contractor requirements. The dosimetry system is operated by PNNL’s Hanford External Dosimetry Program (HEDP) which provides dosimetry services to all Hanford contractors. The primary users of this manual are DOE and DOE contractors at Hanford using the dosimetry services of PNNL. Development and maintenance of this manual is funded directly by DOE and DOE contractors. Its contents have been reviewed and approved by DOE and DOE contractors at Hanford through the Hanford Personnel Dosimetry Advisory Committee (HPDAC) which is chartered and chaired by DOE-RL and serves as means of coordinating dosimetry practices across contractors at Hanford. This manual was established in 1996. Since inception, it has been revised many times and maintained by PNNL as a controlled document with controlled distribution. The first revision to be released through PNNL’s Electronic Records & Information Capture Architecture (ERICA) database was designated Revision 0. Revision numbers that are whole numbers reflect major revisions typically involving changes to all chapters in the document. Revision numbers that include a decimal fraction reflect minor revisions, usually restricted to selected chapters or selected pages in the document.

  9. EPR parameters of amino acid radicals in P. eryngii versatile peroxidase and its W164Y variant computed at the QM/MM level.

    Science.gov (United States)

    Bernini, Caterina; Pogni, Rebecca; Ruiz-Dueñas, Francisco J; Martínez, Angel T; Basosi, Riccardo; Sinicropi, Adalgisa

    2011-03-21

    Quantum mechanics/molecular mechanics (QM/MM) methods, employing density functional theory (DFT), have been used to compute the electron paramagnetic resonance (EPR) parameters of tryptophan and tyrosyl radical intermediates involved in the catalytic cycle of Pleurotus eryngii versatile peroxidase (VP) and its W164Y variant, respectively. These radicals have been previously experimentally detected and characterized both in the two-electron and one-electron activated forms of the enzymes. In this work, the well-studied W164 radical in VP has been chosen for calibration purposes because its spectroscopic properties have been extensively studied by multifrequency EPR and ENDOR spectroscopies. Using a B3LYP/CHARMM procedure, appropriately accounting for electrostatic, such as hydrogen bonding, and steric environmental interactions, a good agreement between the calculated and measured EPR parameters for both radicals has been achieved; g-tensors, hyperfine coupling constants (hfcc) and Mulliken spin densities have been correlated to changes in geometries, hydrogen bond networks and electrostatic environment, with the aim of understanding the influence of the protein surroundings on EPR properties. In addition, the present calculations demonstrate, for VP, the formation of a neutral tryptophan radical, hydrogen bonded to the nearby E243, via a stepwise electron and proton transfer with earlier involvement of a short-lived tryptophan cationic species. Instead, for W164Y, the QM/MM dynamics simulation shows that the tyrosine oxidation proceeds via a concerted electron and proton transfer and is accompanied by a significant reorganization of residues and water molecules surrounding the tyrosyl radical.

  10. Radiation Dosimetry for Quality Control of Food Preservation and Disinfestation

    DEFF Research Database (Denmark)

    McLaughlin, W.L.; Miller, Arne; Uribe, R.M.

    1983-01-01

    In the use of x and gamma rays and scanned electron beams to extend the shelf life of food by delay of sprouting and ripening, killing of microbes, and control of insect population, quality assurance is provided by standardized radiation dosimetry. By strategic placement of calibrated dosimeters...... speed) to meet changes that occur in product and source parameters (e.g. bulk density and radiation spectrum). Routine dosimetry methods and certain corrections of dosimetry data may be selected for the radiations used in typical food processes....

  11. Dosimetry of Auger emitters: Physical and phenomenological approaches

    Energy Technology Data Exchange (ETDEWEB)

    Sastry, K.S.R.; Howell, R.W.; Rao, D.V.; Mylavarapu, V.B.; Kassis, A.I.; Adelstein, S.J.; Wright, H.A.; Hamm, R.N.; Turner, J.E.

    1987-01-01

    Recent radiobiological studies have demonstrated that Auger cascades can cause severe biological damage contrary to expectations based on conventional dosimetry. Several determinants govern these effects, including the nature of the Auger electron spectrum; localized energy deposition; cellular geometry; chemical form of the carrier; cellular localization, concentration, and subcellular distribution of the radionuclide. Conventional dosimetry is inadequate in that these considerations are ignored. Our results provide the basis for biophysical approaches toward subcellular dosimetry of Auger emitters in vitro and in vivo. 12 refs., 7 figs., 2 tabs.

  12. Dosimetry in clinical static magnetic fields using plastic scintillation detectors

    DEFF Research Database (Denmark)

    Stefanowicz, S.; Latzel, H.; Lindvold, Lars René

    2013-01-01

    , however, not clear yet how dosimetry will be conducted as standard methods and might not be easily transferred to systems with clinical magnetic fields. For dosimetry in MRI accelerators, we have tested plastic scintillation detectors (PSD) coupled to optical fibers. They are suitable for real-time and in......-vivo dosimetry in radiation treatments and diagnostics and could be, being all-optical, promising candidates for this application. To study the basic feasibility of using PSDs with organic scintillators in magnetic fields, we measured the response of these dosimeters in presence of magnetic fields up to 1 T...

  13. EPR spin Hamiltonian parameters of encapsulated spin-labels: impact of the hydrogen bonding topology.

    Science.gov (United States)

    Frecus, Bogdan; Rinkevicius, Zilvinas; Murugan, N Arul; Vahtras, Olav; Kongsted, Jacob; Ågren, Hans

    2013-02-21

    Encapsulation of spin-labels into "host" compounds, like cucurbit[n]urils or cyclodextrins, in solutions has profound effects on the EPR spin Hamiltonian parameters of the spin-labels. In this work we study the microscopic origin of the EPR spin Hamiltonian parameters of spin-labels enclosed in hydrophobic cavities. We focus on the dependence of the EPR properties of encapsulated spin-labels on the hydrogen bonding topologies that occur upon encapsulation, and quantize various contributions to these parameters according to specific hydrogen bonding patterns. The obtained results provide refined insight into the role of the hydrogen bonding induced encapsulation shifts of EPR spin Hamiltonian parameters in solvated "spin-label@host compound" complexes.

  14. Irradiation for dating Brazilian fish fossil by thermoluminescence and EPR technique

    Energy Technology Data Exchange (ETDEWEB)

    Sullasi, H.S.; Andrade, M.B.; Ayta, W.E.F.; Frade, M.; Sastry, M.D.; Watanabe, S

    2004-01-01

    Fish fossil from Ceara State, Brazil has been investigated using thermoluminescence and EPR method. In both cases, additive method has been used by irradiating fossil samples to very high doses (tens of kGy). In the case of thermoluminescence, 360 deg. C peak was used for dating. Since the fish fossil contains relatively high concentration of Mn, the EPR Mn{sup 2+}-lines cover carbonate and sulfate radicals signal (sulfur is also present in large amount), therefore 50 mW microwave power was used for EPR measurements. At this high power region Mn{sup 2+}-lines become very little intense and SO{sub 2}{sup -} and CO{sub 2}{sup -} can be detected. Both TL and EPR dating presented an age around 8 Ma. Correction due to spontaneous decay of 360 deg. C peak at ambient temperature gives rise to about {approx}24 Ma of age.

  15. Wormhole and Entanglement (Non-)Detection in the ER=EPR Correspondence

    CERN Document Server

    Bao, Ning; Remmen, Grant N

    2015-01-01

    The recently proposed ER=EPR correspondence postulates the existence of wormholes (Einstein-Rosen bridges) between entangled states (such as EPR pairs). Entanglement is famously known to be unobservable in quantum mechanics, in that there exists no observable (or, equivalently, projector) that can accurately pick out whether a generic state is entangled. Many features of the geometry of spacetime, however, are observables, so one might worry that the presence or absence of a wormhole could identify an entangled state in ER=EPR, violating quantum mechanics, specifically, the property of state-independence of observables. In this note, we establish that this cannot occur: there is no measurement in general relativity that unambiguously detects the presence of a generic wormhole geometry. This statement is the ER=EPR dual of the undetectability of entanglement.

  16. A view of EPR non-locality problems based on Aron's stochastic foundation of relativity

    Science.gov (United States)

    Scheer, Jens

    1990-12-01

    It is argued that the problem of causal anomalies that still may exist in Vigier's explanation of superluminal EPR type correlations may be removed in the framework of Aron's stochastic foundation of relativity.

  17. Wormhole and entanglement (non-)detection in the ER=EPR correspondence

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Ning [Institute for Quantum Information and Matter, California Institute of Technology,Pasadena, CA 91125 (United States); Walter Burke Institute for Theoretical Physics, California Institute of Technology,Pasadena, CA 91125 (United States); Pollack, Jason; Remmen, Grant N. [Walter Burke Institute for Theoretical Physics, California Institute of Technology,Pasadena, CA 91125 (United States)

    2015-11-19

    The recently proposed ER=EPR correspondence postulates the existence of wormholes (Einstein-Rosen bridges) between entangled states (such as EPR pairs). Entanglement is famously known to be unobservable in quantum mechanics, in that there exists no observable (or, equivalently, projector) that can accurately pick out whether a generic state is entangled. Many features of the geometry of spacetime, however, are observables, so one might worry that the presence or absence of a wormhole could identify an entangled state in ER=EPR, violating quantum mechanics, specifically, the property of state-independence of observables. In this note, we establish that this cannot occur: there is no measurement in general relativity that unambiguously detects the presence of a generic wormhole geometry. This statement is the ER=EPR dual of the undetectability of entanglement.

  18. The strength of EPR and ENDOR techniques in revealing structure-function relationships in metalloproteins.

    Science.gov (United States)

    Van Doorslaer, Sabine; Vinck, Evi

    2007-09-01

    Recent technological and methodological advances have strongly increased the potential of electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) techniques to characterize the structure and dynamics of metalloproteins. These developments include the introduction of powerful pulsed EPR/ENDOR methodologies and the development of spectrometers operating at very high microwave frequencies and high magnetic fields. This overview focuses on how valuable information about metalloprotein structure-function relations can be obtained using a combination of EPR and ENDOR techniques. After an overview of the historical development and a limited theoretical description of some of the key EPR and ENDOR techniques, their potential will be highlighted using selected examples of applications to iron-, nickel-, cobalt-, and copper-containing proteins. We will end with an outlook of future developments.

  19. EPR spectroscopy of protein microcrystals oriented in a liquid crystalline polymer medium

    Science.gov (United States)

    Caldeira, Jorge; Figueirinhas, João Luis; Santos, Celina; Godinho, Maria Helena

    2004-10-01

    Correlation of the g-tensor of a paramagnetic active center of a protein with its structure provides a unique experimental information on the electronic structure of the metal site. To address this problem, we made solid films containing metalloprotein ( Desulfovibrio gigas cytochrome c3) microcrystals. The microcrystals in a liquid crystalline polymer medium (water/hydroxypropylcellulose) were partially aligned by a shear flow. A strong orientation effect of the metalloprotein was observed by EPR spectroscopy and polarizing optical microscopy. The EPR spectra of partially oriented samples were simulated, allowing for molecular orientation distribution function determination. The observed effect results in enhanced sensitivity and resolution of the EPR spectra and provides a new approach towards the correlation of spectroscopic data, obtained by EPR or some other technique, with the three-dimensional structure of a protein or a model compound.

  20. Study of dose-response and radical decay curves of gamma irradiated norfloxacin using EPR spectroscopy

    Science.gov (United States)

    Sütçü, Kerem; Osmanoǧlu, Yunus Emre

    2017-02-01

    In this study, Electron Paramagnetic Resonance (EPR) spectra of unirradiated and γ-irradiated at doses of 1, 5, 10, 12 and 15 kGy norfloxacin (NOF) were investigated. Before irradiation no EPR signal were observed. After irradiation a weak singlet signal at g = 2.0039 were obtained at room temperature. In order to describe the variation of EPR signal intensity with absorbed radiation dose, several mathematical equations were tried. Increasing irradiation dose up to 15 kGy has increased the signal intensity of the central signal however, no significant changes were observed in g spectroscopic splitting factor. The stability of signal intensity of irradiated NOF was studied over a storage period of 200 days. According to analyses conducted, EPR spectroscopy can be used to distinguish irradiated and unirradiated samples from each other.

  1. Application of electron paramagnetic resonance (EPR) spectroscopy and imaging in drug delivery research - chances and challenges.

    Science.gov (United States)

    Kempe, Sabine; Metz, Hendrik; Mäder, Karsten

    2010-01-01

    Electron Paramagnetic Resonance (EPR) spectroscopy is a powerful technique to study chemical species with unpaired electrons. Since its discovery in 1944, it has been widely used in a number of research fields such as physics, chemistry, biology and material and food science. This review is focused on its application in drug delivery research. EPR permits the direct measurement of microviscosity and micropolarity inside drug delivery systems (DDS), the detection of microacidity, phase transitions and the characterization of colloidal drug carriers. Additional information about the spatial distribution can be obtained by EPR imaging. The chances and also the challenges of in vitro and in vivo EPR spectroscopy and imaging in the field of drug delivery are discussed.

  2. Determination of the Average Native Background and the Light-Induced EPR Signals and their Variation in the Teeth Enamel Based on Large-Scale Survey of the Population.

    Science.gov (United States)

    Ivannikov, Alexander I; Khailov, Artem M; Orlenko, Sergey P; Skvortsov, Valeri G; Stepanenko, Valeri F; Zhumadilov, Kassym Sh; Williams, Benjamin B; Flood, Ann B; Swartz, Harold M

    2016-12-01

    The aim of the study is to determine the average intensity and variation of the native background signal amplitude (NSA) and of the solar light-induced signal amplitude (LSA) in electron paramagnetic resonance (EPR) spectra of tooth enamel for different kinds of teeth and different groups of people. These values are necessary for determination of the intensity of the radiation-induced signal amplitude (RSA) by subtraction of the expected NSA and LSA from the total signal amplitude measured in L-band for in vivo EPR dosimetry. Variation of these signals should be taken into account when estimating the uncertainty of the estimated RSA. A new analysis of several hundred EPR spectra that were measured earlier at X-band in a large-scale examination of the population of the Central Russia was performed. Based on this analysis, the average values and the variation (standard deviation, SD) of the amplitude of the NSA for the teeth from different positions, as well as LSA in outer enamel of the front teeth for different population groups, were determined. To convert data acquired at X-band to values corresponding to the conditions of measurement at L-band, the experimental dependencies of the intensities of the RSA, LSA and NSA on the m.w. power, measured at both X and L-band, were analysed. For the two central upper incisors, which are mainly used in in vivo dosimetry, the mean LSA annual rate induced only in the outer side enamel and its variation were obtained as 10 ± 2 (SD = 8) mGy y(-1), the same for X- and L-bands (results are presented as the mean ± error of mean). Mean NSA in enamel and its variation for the upper incisors was calculated at 2.0 ± 0.2 (SD = 0.5) Gy, relative to the calibrated RSA dose-response to gamma radiation measured under non-power saturation conditions at X-band. Assuming the same value for L-band under non-power saturating conditions, then for in vivo measurements at L-band at 25 mW (power saturation conditions), a mean NSA and its

  3. Transport de paires EPR dans des structures mesoscopiques

    Science.gov (United States)

    Dupont, Emilie

    Dans cette these, nous nous sommes particulierement interesses a la propagation de paires EPR1 delocalisees et localisees, et a l'influence d'un supraconducteur sur le transport de ces paires. Apres une introduction de cette etude, ainsi que du cadre scientifique qu'est l'informatique quantique dans lequel elle s'inscrit, nous allons dans le chapitre 1 faire un rappel sur le systeme constitue de deux points quantiques normaux entoures de deux fils supraconducteurs. Cela nous permettra d'introduire une methode de calcul qui sera reutilisee par la suite, et de trouver egalement le courant Josephson produit par ce systeme transforme en SQUID-dc par l'ajout d'une jonction auxiliaire. Le SQUID permet de mesurer l'etat de spin (singulet ou triplet), et peut etre forme a partir d'autres systemes que nous etudierons ensuite. Dans le chapitre 2, nous rappellerons l'etude detaillee d'un intricateur d'Andreev faite par un groupe de Bale. La matrice T, permettant d'obtenir le courant dans les cas ou les electrons sont separes spatialement ou non, sera etudiee en detail afin d'en faire usage au chapitre suivant. Le chapitre 3 est consacre a l'etude de l'influence du bruit sur le fonctionnement de l'intricateur d'Andreev. Ce bruit modifie la forme du courant jusqu'a aboutir a d'autres conditions de fonctionnement de l'intricateur. En effet, le bruit present sur les points quantiques peut perturber le transport des paires EPR par l'intermediaire des degres de liberte. Nous montrerons que, du fait de l'"intrication" entre la charge de la paire et le bruit, la paire est detruite pour des temps longs. Cependant, le resultat le plus important sera que le bruit perturbe plus le transport des paires delocalisees, qui implique une resonance de Breit-Wigner a deux particules. Le transport parasite n'implique pour sa part qu'une resonance de Breit-Wigner a une particule. Dans le chapitre 4, nous reviendrons au systeme constitue de deux points quantiques entoures de deux fils

  4. Evaluation of the original dose in irradiated dried fruit by EPR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    D' Oca, Maria Cristina, E-mail: mcristina.doca@unipa.it [Dipartimento Farmacochimico, Tossicologico e Biologico, Universita di Palermo, via Archirafi 32, 90123 Palermo (Italy); Bartolotta, Antonio [Dipartimento Farmacochimico, Tossicologico e Biologico, Universita di Palermo, via Archirafi 32, 90123 Palermo (Italy)

    2011-09-15

    The electron paramagnetic resonance spectroscopy (EPR) is one of the physical methods, recommended by the European Committee for Standardization, for the identification of irradiated food containing cellulose, such as dried fruit. In this work the applicability of EPR as identification method of irradiated pistachios, hazelnuts, peanuts, chestnuts, pumpkin seeds is evaluated; the time stability of the radiation induced signal is studied and the single aliquot additive dose method is used to evaluate the dose in the product.

  5. EPR Properties of Concentrated NdVO4 Single Crystal System.

    Science.gov (United States)

    Kaczmarek, S M; Fuks, H; Berkowski, M; Głowacki, M; Bojanowski, B

    Single crystals of NdVO4 were grown by the Czochralski method under ambient pressure in a nitrogen atmosphere. Obtained crystals were transparent with strong violet coloring. Temperature and angular dependences of electron paramagnetic resonance (EPR) spectra of the samples in the 3-103 K temperature range were analyzed applying Dyson like lineshape typically used for concentrated magnetic system. EPR-NMR program was used to find local symmetry and spin-Hamiltonian parameters of neodymium ions.

  6. Deterministic quantum key distribution based on Gaussian-modulated EPR correlations

    Institute of Scientific and Technical Information of China (English)

    He Guang-Qiang; Zeng Gui-Hua

    2006-01-01

    This paper proposes a deterministic quantum key distribution scheme based on Gaussian-modulated continuous variable EPR correlations. This scheme can implement fast and efficient key distribution. The security is guaranteed by continuous variable EPR entanglement correlations produced by nondegenerate optical parametric amplifier. For general beam splitter eavesdropping strategy, the secret information rate△I = I(α,β) - I(α,ε) is calculated in view of Shannon information theory. Finally the security analysis is presented.

  7. Preparation and applicability of fresh fruit samples for the identification of radiation treatment by EPR

    Energy Technology Data Exchange (ETDEWEB)

    Yordanov, Nicola D. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)], E-mail: ndyepr@bas.bg; Aleksieva, Katerina [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

    2009-03-15

    The results of electron paramagnetic resonance (EPR) study on fresh fruits (whole pulp of pears, apples, peaches, apricots, avocado, kiwi and mango) before and after gamma-irradiation are reported using two drying procedures before EPR investigation. In order to remove water from non-irradiated and irradiated samples of the first batch, the pulp of fresh fruits is pressed, and the solid residue is washed with alcohol and dried at room temperature. The fruits of the second batch are pressed and dried in a standard laboratory oven at 40 deg. C. The results obtained with both drying procedures are compared. All samples under study show a singlet EPR line with g=2.0048{+-}0.0005 before irradiation. Irradiation gives rise to typical 'cellulose-like' EPR spectrum featuring one intensive line with g=2.0048{+-}0.0005 and two very weak satellite lines situated 3 mT at left and right of the central line. Only mango samples show a singlet line after irradiation. The fading kinetics of radiation-induced EPR signal is studied for a period of 50 days after irradiation. When the irradiated fruit samples are stored in their natural state and dried just before each EPR measurement, the satellite lines are measurable for less than 17 days of storage. Irradiated fruit samples, when stored dried, lose for 50 days ca. 40% of their radiation-induced radicals if treated with alcohol or ca. 70% if dried in an oven. The reported results unambiguously show that the presence of the satellite lines in the EPR spectra could be used for identification of radiation processing of fresh fruits, thus extending the validity of European Protocol EN 1787 (2000). Foodstuffs-Detection of Irradiated Food Containing Cellulose by EPR Spectroscopy. European Committee for Standardisation. Brussels for dry herbs.

  8. EPR Entangled States for Bipartite Kinematics and New Bosonic Representation of SU(2) Algebra

    Institute of Scientific and Technical Information of China (English)

    FANHong-Yi; CHENJun-Hua

    2003-01-01

    We find that the Einstein-Podolsky-Rosen (EPR) entangled state representation descr/bing bipartite kinematics is closely related to a new Bose operator realization of SU(2) Lie algebra. By virtue of the new realization some ttamiltonian eigenfunction equation can be directly converted to the generalized confluent equation in the EPR entangled state representation and its solution is obtainable. This thus provides a new approach for studying dynamics of angular momentum systems.

  9. EPR Entangled States for Bipartite Kinematics and New Bosonic Representation of SU(2) Algebra

    Institute of Scientific and Technical Information of China (English)

    FAN Hong-Yi; CHEN Jun-Hua

    2003-01-01

    We find that the Einstein-Podolsky-Rosen (EPR) entangled state representation describing bipartite kinematics is closely related to a new Bose operator realization of SU(2) Lie algebra. By virtue of the new realization some Hamiltonian eigenfunction equation can be directly converted to the generalized confluent equation in the EPR entangled state representation and its solution is obtainable. This thus provides a new approach for studying dynamics of angular momentum systems.

  10. EPR character of gadolinium complexes with noncyclic polyether Schiff bases and its solvent effects

    Institute of Scientific and Technical Information of China (English)

    姚克敏; 陈德余; 王晓南; 邓宁

    1996-01-01

    EPR characters of three new gadolinium complexes with noncydic polyether Schiff bases in powder or organic solvents, including various oxyethylene chain lengths and different substituting groups in ligands, are investigated respectively. Some regularities are summed up. The difference of EPR character in various solvents, particularly at different temperatures, has been examined. The ’single peak effect’ due to THF solvent at low temperature is observed for the first time. This phenomenon is explicated.

  11. The EPR detection of foods preserved with the use of ionizing radiation

    Science.gov (United States)

    Stachowicz, W.; Burlińska, G.; Michalik, J.; Dziedzic-Gocławska, A.; Ostrowski, K.

    1995-02-01

    Solid constituents extracted from irradiated foods have been examined by the epr (esr) spectroscopy. It has been proved that some epr active species produced by radiation in foods are specific and stable enough to be used for the detection of irradiation treatment. The most promising results have been obtained with bones extracted from frozen raw meat (beef, pork, poultry and fish), with seeds of fruits (dates and figs), with dried mushrooms, gelatin and macaroni.

  12. Preparation and applicability of fresh fruit samples for the identification of radiation treatment by EPR

    Science.gov (United States)

    Yordanov, Nicola D.; Aleksieva, Katerina

    2009-03-01

    The results of electron paramagnetic resonance (EPR) study on fresh fruits (whole pulp of pears, apples, peaches, apricots, avocado, kiwi and mango) before and after gamma-irradiation are reported using two drying procedures before EPR investigation. In order to remove water from non-irradiated and irradiated samples of the first batch, the pulp of fresh fruits is pressed, and the solid residue is washed with alcohol and dried at room temperature. The fruits of the second batch are pressed and dried in a standard laboratory oven at 40 °C. The results obtained with both drying procedures are compared. All samples under study show a singlet EPR line with g=2.0048±0.0005 before irradiation. Irradiation gives rise to typical "cellulose-like" EPR spectrum featuring one intensive line with g=2.0048±0.0005 and two very weak satellite lines situated 3 mT at left and right of the central line. Only mango samples show a singlet line after irradiation. The fading kinetics of radiation-induced EPR signal is studied for a period of 50 days after irradiation. When the irradiated fruit samples are stored in their natural state and dried just before each EPR measurement, the satellite lines are measurable for less than 17 days of storage. Irradiated fruit samples, when stored dried, lose for 50 days ca. 40% of their radiation-induced radicals if treated with alcohol or ca. 70% if dried in an oven. The reported results unambiguously show that the presence of the satellite lines in the EPR spectra could be used for identification of radiation processing of fresh fruits, thus extending the validity of European Protocol EN 1787 (2000). Foodstuffs—Detection of Irradiated Food Containing Cellulose by EPR Spectroscopy. European Committee for Standardisation. Brussels for dry herbs.

  13. EPR safety. Consideration of the internal and external hazards in the safety studies; Surete du reacteur EPR. Prise en compte des agressions internes et externes dans les etudes de surete EPR

    Energy Technology Data Exchange (ETDEWEB)

    Gueguin, H. [Electricite de France (EDF-DIN), Centre National d' Equipement Nucleaire, Service Controle Commande, 92 - Montrouge (France)

    2008-04-15

    The author presents the main points of the Preliminary Safety Report of EDF on the EPR reactor safety. It concerns the considerations of the internal (fire, flood, explosions, pipes failures) and external (earthquakes, airplane falls, explosions, exceptional natural disasters, extreme meteorological conditions) damages. It presents how the safety report takes into account the aggression. (A.L.B.)

  14. EPR and IR spectral investigations on some leafy vegetables of Indian origin

    Science.gov (United States)

    Prasuna, C. P. Lakshmi; Chakradhar, R. P. S.; Rao, J. L.; Gopal, N. O.

    2009-09-01

    EPR spectral investigations have been carried out on four edible leafy vegetables of India, which are used as dietary component in day to day life. In Rumex vesicarius leaf sample, EPR spectral investigations at different temperatures indicate the presence of anti-ferromagnetically coupled Mn(IV)-Mn(IV) complexes. EPR spectra of Trigonella foenum graecum show the presence of Mn ions in multivalent state and Fe 3+ ions in rhombic symmetry. EPR spectra of Basella rubra indicate the presence of Mn(IV)-O-Mn(IV) type complexes. The EPR spectra of Basella rubra have been studied at different temperatures. It is found that the spin population for the resonance signal at g = 2.06 obeys the Boltzmann distribution law. The EPR spectra of Moringa oliefera leaves show the presence of Mn 2+ ions. Radiation induced changes in free radical of this sample have also been studied. The FT-IR spectra of Basella rubra and Moringa oliefera leaves show the evidences for the protein matrix bands and those corresponding to carboxylic C dbnd O bonds.

  15. Using ANN and EPR models to predict carbon monoxide concentrations in urban area of Tabriz

    Directory of Open Access Journals (Sweden)

    Mohammad Shakerkhatibi

    2015-09-01

    Full Text Available Background: Forecasting of air pollutants has become a popular topic of environmental research today. For this purpose, the artificial neural network (AAN technique is widely used as a reliable method for forecasting air pollutants in urban areas. On the other hand, the evolutionary polynomial regression (EPR model has recently been used as a forecasting tool in some environmental issues. In this research, we compared the ability of these models to forecast carbon monoxide (CO concentrations in the urban area of Tabriz city. Methods: The dataset of CO concentrations measured at the fixed stations operated by the East Azerbaijan Environmental Office along with meteorological data obtained from the East Azerbaijan Meteorological Bureau from March 2007 to March 2013, were used as input for the ANN and EPR models. Results: Based on the results, the performance of ANN is more reliable in comparison with EPR. Using the ANN model, the correlation coefficient values at all monitoring stations were calculated above 0.85. Conversely, the R2 values for these stations were obtained <0.41 using the EPR model. Conclusion: The EPR model could not overcome the nonlinearities of input data. However, the ANN model displayed more accurate results compared to the EPR. Hence, the ANN models are robust tools for predicting air pollutant concentrations.

  16. One click film (OCF) dosimetry system for routine QA

    Energy Technology Data Exchange (ETDEWEB)

    Kim, So Young; Yi, Byong Yong; Kim, Jong Hoon; Ahn, Seung Do; Lee, Sang Wook; Choi, Eun Kyoung [Asan Medical Center, College of Medicine, University of Ulsan, Seoul (Korea, Republic of); Joo, Kwan Sik [MyongJi University, Yongin (Korea, Republic of)

    2002-12-15

    To develop a practical film dosimetry system for routine Quality Assurance (QA). An One Click Film (OCF) Dosimetry system was designed to perform swift routine QA with functions including automatic fog value elimination, angle adjustment, automatic symmetry calculation, and realtime profile generation with the ability to display realtime three-dimensional dose distributions. The most frequently used functions for routine QA, such as the elimination of the fog value, conversion into an H and D curve, symmetry, and isodose distribution, can be achieved with only one click. Reliable results were achieved with the OCF dosimetry with simpler steps than other commercially available film dosimetry systems for routine QA. More research on the refined user interface will make this system be clinically useful.

  17. Retrospective dosimetry analyses of reactor vessel cladding samples

    Energy Technology Data Exchange (ETDEWEB)

    Greenwood, L. R.; Soderquist, C. Z. [Battelle Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Fero, A. H. [Westinghouse Electric Company, Cranberry Twp., PA 16066 (United States)

    2011-07-01

    Reactor pressure vessel cladding samples for Ringhals Units 3 and 4 in Sweden were analyzed using retrospective reactor dosimetry techniques. The objective was to provide the best estimates of the neutron fluence for comparison with neutron transport calculations. A total of 51 stainless steel samples consisting of chips weighing approximately 100 to 200 mg were removed from selected locations around the pressure vessel and were sent to Pacific Northwest National Laboratory for analysis. The samples were fully characterized and analyzed for radioactive isotopes, with special interest in the presence of Nb-93m. The RPV cladding retrospective dosimetry results will be combined with a re-evaluation of the surveillance capsule dosimetry and with ex-vessel neutron dosimetry results to form a comprehensive 3D comparison of measurements to calculations performed with 3D deterministic transport code. (authors)

  18. Proceedings of the third conference on radiation protection and dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Swaja, R.E.; Sims, C.S.; Casson, W.H. [eds.

    1991-10-01

    The Third Conference on Radiation Protection and Dosimetry was held during October 21--24, 1991, at the Sheraton Plaza Hotel in Orlando, Florida. This meeting was designed with the objectives of promoting communication among applied, research, regulatory, and standards personnel involved in radiation protection, and providing them with sufficient information to evaluate their programs. To meet these objectives, a technical program consisting of more than 75 invited and contributed oral presentations encompassing all aspects of radiation protection was prepared. General topics considered in the technical session included external dosimetry, internal dosimetry, instruments, accident dosimetry, regulations and standards, research advances, and applied program experience. In addition, special sessions were held to afford attendees the opportunity to make short presentations of recent work or to discuss topics of general interest. Individual reports are processed separately on the database.

  19. X-Ray Crystallographic Analysis, EPR Studies, and Computational Calculations of a Cu(II) Tetramic Acid Complex

    Science.gov (United States)

    Matiadis, Dimitrios; Tsironis, Dimitrios; Stefanou, Valentina; Igglessi–Markopoulou, Olga; McKee, Vickie; Sanakis, Yiannis; Lazarou, Katerina N.

    2017-01-01

    In this work we present a structural and spectroscopic analysis of a copper(II) N-acetyl-5-arylidene tetramic acid by using both experimental and computational techniques. The crystal structure of the Cu(II) complex was determined by single crystal X-ray diffraction and shows that the copper ion lies on a centre of symmetry, with each ligand ion coordinated to two copper ions, forming a 2D sheet. Moreover, the EPR spectroscopic properties of the Cu(II) tetramic acid complex were also explored and discussed. Finally, a computational approach was performed in order to obtain a detailed and precise insight of product structures and properties. It is hoped that this study can enrich the field of functional supramolecular systems, giving place to the formation of coordination-driven self-assembly architectures. PMID:28316540

  20. Nickelacyclic-cobaltocene vs. nickelacyclic-nickelocene. Synthesis, X-ray structures, electron transfer activity, EPR spectroscopy, and theoretical calculations.

    Science.gov (United States)

    Buchalski, Piotr; Kamińska, Elzbieta; Piwowar, Katarzyna; Suwińska, Kinga; Jerzykiewicz, Lucjan; Rossi, Fulvio; Laschi, Franco; de Biani, Fabrizia Fabrizi; Zanello, Piero

    2009-06-01

    Reactions of 9-nickelafluorenyllithium with cobalt and nickel pentamethylcyclopentadienyl-acetylacetonates resulted in the formation of the novel nickelacyclic-cobaltocene 2 and nickelacyclic-nickelocene 3, respectively, in which the central metal atom is bonded to the nickelafluorenyl ring. On the basis of their redox propensity, compounds 2 and 3 were oxidized to the corresponding monocations [2](+) and [3](+). The crystal and molecular structures of both the redox couples were determined by single-crystal X-ray analysis. In spite of their structural similarity, they display a rather different electron transfer ability. To throw light on such an aspect, the pertinent redox couples have been examined by EPR spectroscopy and the nature of the frontier orbitals involved in the redox activity of the neutral precursors has been supported by extended Huckel theoretical calculations.

  1. Protonated paramagnetic redox forms of di-o-quinone bridged with p-phenylene-extended TTF: A EPR spectroscopy study

    Directory of Open Access Journals (Sweden)

    Nikolay O. Chalkov

    2016-11-01

    Full Text Available The chemical oxidation and reduction processes of deprotonated, direduced o-quinone-exTTF-o-quinone in protic solvents were studied by EPR spectroscopy. The formation of relatively stable paramagnetic protonated redox forms of the parent triad was very surprising. The character of spin-density distribution in the semiquinone–quinone and semiquinone–catechol redox forms indicates that the p-phenylene-extended tetrathiafulvalene connector provides a quite effective electronic communication channel between dioxolene coordination sites. It was found that the deprotonated, direduced o-quinone-exTTF-o-quinone is capable to reduction of the metal copper in solution. The radical anion species formed in this reaction exists in solution as a solvent-separated ion pair with a copper cation. A character of spin-density distribution in a radical anion species leads to the conclusion that the ligand corresponds to type III of the Robin–Day classification.

  2. Dosimetry in Thermal Neutron Irradiation Facility at BMRR

    OpenAIRE

    2016-01-01

    Radiation dosimetry for Neutron Capture Therapy (NCT) has been performed since 1959 at Thermal Neutron Irradiation Facility (TNIF) of the three-megawatt light-water cooled Brookhaven Medical Research Reactor (BMRR). In the early 1990s when more effective drug carriers were developed for NCT, in which the eye melanoma and brain tumors in rats were irradiated in situ, extensive clinical trials of small animals began using a focused thermal neutron beam. To improve the dosimetry at irradiation f...

  3. Why is a high accuracy needed in dosimetry. [Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Lanzl, L.H.

    1976-01-01

    Dose and exposure intercomparisons on a national or international basis have become an important component of quality assurance in the practice of good radiotherapy. A high degree of accuracy of ..gamma.. and x radiation dosimetry is essential in our international society, where medical information is so readily exchanged and used. The value of accurate dosimetry lies mainly in the avoidance of complications in normal tissue and an optimal degree of tumor control.

  4. EPID dosimetry for pretreatment quality assurance with two commercial systems.

    Science.gov (United States)

    Bailey, Daniel W; Kumaraswamy, Lalith; Bakhtiari, Mohammad; Malhotra, Harish K; Podgorsak, Matthew B

    2012-07-05

    This study compares the EPID dosimetry algorithms of two commercial systems for pretreatment QA, and analyzes dosimetric measurements made with each system alongside the results obtained with a standard diode array. 126 IMRT fields are examined with both EPID dosimetry systems (EPIDose by Sun Nuclear Corporation, Melbourne FL, and Portal Dosimetry by Varian Medical Systems, Palo Alto CA) and the diode array, MapCHECK (also by Sun Nuclear Corporation). Twenty-six VMAT arcs of varying modulation complexity are examined with the EPIDose and MapCHECK systems. Optimization and commissioning testing of the EPIDose physics model is detailed. Each EPID IMRT QA system is tested for sensitivity to critical TPS beam model errors. Absolute dose gamma evaluation (3%, 3 mm, 10% threshold, global normalization to the maximum measured dose) yields similar results (within 1%-2%) for all three dosimetry modalities, except in the case of off-axis breast tangents. For these off-axis fields, the Portal Dosimetry system does not adequately model EPID response, though a previously-published correction algorithm improves performance. Both MapCHECK and EPIDose are found to yield good results for VMAT QA, though limitations are discussed. Both the Portal Dosimetry and EPIDose algorithms, though distinctly different, yield similar results for the majority of clinical IMRT cases, in close agreement with a standard diode array. Portal dose image prediction may overlook errors in beam modeling beyond the calculation of the actual fluence, while MapCHECK and EPIDose include verification of the dose calculation algorithm, albeit in simplified phantom conditions (and with limited data density in the case of the MapCHECK detector). Unlike the commercial Portal Dosimetry package, the EPIDose algorithm (when sufficiently optimized) allows accurate analysis of EPID response for off-axis, asymmetric fields, and for orthogonal VMAT QA. Other forms of QA are necessary to supplement the limitations of the

  5. Basic principles in the radiation dosimetry of nuclear medicine.

    Science.gov (United States)

    Stabin, Michael; Xu, Xie George

    2014-05-01

    The basic principles of the use of radiation dosimetry in nuclear medicine are reviewed. The basic structure of the main mathematical equations are given and formal dosimetry systems are discussed. An extensive overview of the history and current status of anthropomorphic models (phantoms) is given. The sources and magnitudes of uncertainties in calculated internal dose estimates are reviewed. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. A practical three-dimensional dosimetry system for radiation therapy

    OpenAIRE

    Guo, Pengyi; Adamovics, John; Oldham, Mark

    2006-01-01

    There is a pressing need for a practical three-dimensional (3D) dosimetry system, convenient for clinical use, and with the accuracy and resolution to enable comprehensive verification of the complex dose distributions typical of modern radiation therapy. Here we introduce a dosimetry system that can achieve this challenge, consisting of a radiochromic dosimeter (PRESAGE™) and a commercial optical computed tomography (CT) scanning system (OCTOPUS™). PRESAGE™ is a transparent material with com...

  7. Individual dosimetry of workers and patients: implementation and perspectives; La dosimetrie individuelle des travailleurs et de patients: mise en oeuvre et perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Rannou, A.; Aubert, B.; Lahaye, Th.; Scaff, P.; Casanova, Ph.; Van Bladel, L.; Queinnec, F.; Valendru, N.; Jehanno, J.; Grude, E.; Berard, Ph.; Desbree, A.; Kafrouni, H.; Paquet, F.; Vanhavere, F.; Bridier, A.; Ginestet, Ch.; Magne, S.; Donadille, L.; Bordy, J.M.; Bottollier-Depois, J.F.; Barrere, J.L.; Ferragut, A.; Metivier, H.; Gaillard-Lecanu, E

    2008-07-01

    These days organised by the section of the technical protection of the S.F.R.P. review the different techniques of dosimetry used in France and Europe, and present the future orientations.The different interventions are as follow: Individual exposures of the workers: historic assessment and perspectives; medical exposure: where are the doses; legal obligations in individual dosimetry: which are the objective and the need on the subject; the dosimetry follow-up of workers by the S.I.S.E.R.I. system: assessment and perspectives; impact of the norm ISO 20553 on the follow-up of internal exposure; the implementation of the patient dose measurement in Belgium; techniques of passive dosimetry used in Europe; Supervision radiation protection at EDF: long term and short term approach; Comparison active and passive dosimetry at Melox; methodology for the choice of new neutron dosemeters; the working group M.E.D.O.R.: guide of internal dosimetry for the use of practitioners; O.E.D.I.P.E.: tool of modeling for the personalized internal dosimetry; the use of the Monte-Carlo method for the planning of the cancer treatment by radiotherapy becomes a reality; the works of the committee 2 of the ICRP; passive dosimetry versus operational dosimetry: situation in Europe; Implementation of the in vivo dosimetry in a radiotherapy department: experience of the Gustave Roussy institute; experience feedback on the in vivo measures in radiotherapy, based on the use of O.S.L. pellets; multi points O.S.L. instrumentation for the radiation dose monitoring in radiotherapy; dosimetry for extremities for medical applications: principle results of the European contract C.O.N.R.A.D.; references and perspectives in dosimetry; what perspectives for numerical dosimetry, an example: Sievert; system of dose management: how to answer to needs; the last technical evolutions in terms of electronic dosimetry in nuclear power plant; the fourth generation type reactors: what dosimetry. (N.C.)

  8. The radiation dosimetry of intrathecally administered radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Stabin, M.G. [Oak Ridge Inst. for Science and Education, TN (United States); Evans, J.F. [Ohio State Univ., Columbus, OH (United States)

    1999-01-01

    The radiation dose to the spine, spinal cord, marrow, and other organs of the body from intrathecal administration of several radiopharmaceuticals was studied. Anatomic models were developed for the spine, spinal cerebrospinal fluid (CSF), spinal cord, spinal skeleton, cranial skeleton, and cranial CSF. A kinetic model for the transport of CSF was used to determine residence times in the CSF; material leaving the CSF was thereafter assumed to enter the bloodstream and follow the kinetics of the radiopharmaceutical as if intravenously administered. The radiation transport codes MCNP and ALGAMP were used to model the electron and photon transport and energy deposition. The dosimetry of Tc-99m DTPA and HSA, In-111 DTPA, I-131 HSA, and Yb-169 DTPA was studied. Radiation dose profiles for the spinal cord and marrow in the spine were developed and average doses to all other organs were estimated, including dose distributions within the bone and marrow.

  9. Accidental neutron dosimetry with human hair

    Science.gov (United States)

    Ekendahl, Daniela; Bečková, Věra; Zdychová, Vlasta; Bulánek, Boris; Prouza, Zdeněk; Štefánik, Milan

    2014-11-01

    Human hair contains sulfur, which can be activated by fast neutrons. The 32S(n,p)32P reaction with a threshold of 2.5 MeV was used for fast neutron dose estimation. It is a very important parameter for individual dose reconstruction with regards to the heterogeneity of the neutron transfer to the human body. Samples of human hair were irradiated in a radial channel of a training reactor VR-1. 32P activity in hair was measured both, directly by means of a proportional counter, and as ash dispersed in a liquid scintillator. Based on neutron spectrum estimation, a relationship between the neutron dose and induced activity was derived. The experiment verified the practical feasibility of this dosimetry method in cases of criticality accidents or malevolent acts with nuclear materials.

  10. Dosimetry for radiocolloid therapy of cystic craniopharyngiomas

    CERN Document Server

    Rojas, E L; Lallena, A M; Bodineau, C; Galan, P; Al-Dweri, Feras M.O.; Lallena, Antonio M.; Bodineau, Coral; Galan, Pedro

    2003-01-01

    The dosimetry for radiocolloid therapy of cystic craniopharyngiomas is investigated. Analytical calculations based on the Loevinger and the Berger formulae for electrons and photons, respectively, are compared with Monte Carlo simulations. The role of the material of which the colloid introduced inside the craniopharyngioma is made of as well as that forming the cyst wall is analyzed. It is found that the analytical approaches provide a very good description of the simulated data in the conditions where they can be applied (i.e., in the case of a uniform and infinite homogeneous medium). However, the consideration of the different materials and interfaces produces a strong reduction of the dose delivered to the cyst wall in relation to that predicted by the Loevinger and the Berger formulae.

  11. Thermoluminescence and EPR studies on natural petalite crystals

    Energy Technology Data Exchange (ETDEWEB)

    Souza, S.O.; Chubaci, J.F.D.; Watanabe, S. [Department of Nuclear Physics, Institute of Physics, University of Sao Paulo, Sao Paulo, SP (Brazil); Christopher Selvin, P. [NGM College, Pollachi, Tamil Nadu (India); Sastry, M.D. [Bhabha Atomic Research Center, Bombay (India)

    2002-07-07

    Thermally stimulated luminescence of natural mineral petalite (LiAlSi{sub 4}O{sub 10}) crystals was investigated and the possible electron/hole traps responsible for thermoluminescence (TL) emission were identified using optical absorption and electron paramagnetic resonance (EPR) measurements. The glow curves for natural samples, obtained with a heating rate of 4C s{sup -1}, show two glow peaks at 160 deg. C and 330 deg. C. Pre-annealed and subsequently irradiated samples give rise to three glow peaks at 175 deg. C, 340 deg. C and 435 deg. C. An isochronal thermal study established correlation between the first glow peak and Ti{sup 3+}-like trap centre and E'{sub 1}-centre and Al-O{sup -}-Al-like recombination centres. The second TL peak at 340 deg. C may be related to the E{sub 1}' centres formed on irradiation. A mechanism for the observed TL is suggested. (author)

  12. Wave Detection Beyond the Standard Quantum Limit via EPR Entanglement

    Science.gov (United States)

    Ma, Yiqiu; Miao, Haixing; Pang, Belinda; Evans, Matthew; Zhao, Chunnong; Harms, Jan; Schnabel, Roman; Chen, Yanbei

    2017-01-01

    The Standard Quantum Limit in continuous monitoring of a system is given by the trade-off of shot noise and back-action noise. In gravitational-wave detectors, such as Advanced LIGO, both contributions can simultaneously be squeezed in a broad frequency band by injecting a spectrum of squeezed vacuum states with a frequency-dependent squeeze angle. This approach requires setting up an additional long base-line, low-loss filter cavity in a vacuum system at the detector's site. Here, we show that the need for such a filter cavity can be eliminated, by exploiting EPR-entangled signal and idler beams. By harnessing their mutual quantum correlations and the difference in the way each beam propagates in the interferometer, we can engineer the input signal beam to have the appropriate frequency dependent conditional squeezing once the out-going idler beam is detected. Our proposal is appropriate for all future gravitational-wave detectors for achieving sensitivities beyond the Standard Quantum Limit.

  13. EPR identification of intrinsic defects in SiC

    Energy Technology Data Exchange (ETDEWEB)

    Umeda, T.; Mizuochi, N. [University of Tsukuba, Tsukuba 305-8550 (Japan); Son, N.T.; Janzen, E. [Department of Physics, Chemistry and Biology, Linkoeping University, Linkoeping (Sweden); Ohshima, T. [Japan Atomic Energy Agency, Takasaki 370-1292 (Japan); Isoya, J.

    2008-07-15

    The structure determination of intrinsic defects in 4H-SiC, 6H-SiC, and 3C-SiC by means of EPR is based on measuring the angular dependence of the {sup 29}Si/{sup 13}C hyperfine (HF) satellite lines, from which spin densities, sp-hybrid ratio, and p-orbital direction can be determined over major atoms comprising a defect. In most cases, not only the assignment of the variety due to the inequivalent sites (h- and k-sites in 4H-SiC) but also the identification of the defect species is accomplished through the comparison of the obtained HF parameters with those obtained from first principles calculations. Our works of identifying vacancy-related defects such as the monovacancies, divacancies, and antisite-vacancy pairs in 4H-SiC are reviewed. In addition, it is demonstrated that the observation of the central line of the T{sub V2a} center of S=3/2 has been achieved by pulsed-ELDOR. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. New Slant on the EPR-Bell Experiment

    CERN Document Server

    Evans, Peter; Wharton, K B

    2010-01-01

    The best case for thinking that quantum mechanics is nonlocal rests on Bell's Theorem, and later results of the same kind. However, the correlations characteristic of EPR-Bell (EPRB) experiments also arise in familiar cases elsewhere in QM, where the two measurements involved are timelike rather than spacelike separated; and in which the correlations are usually assumed to have a local causal explanation, requiring no action-at-a-distance. It is interesting to ask how this is possible, in the light of Bell's Theorem. We investigate this question, and present two options. Either (i) the new cases are nonlocal, too, in which case action-at-a-distance is more widespread in QM than has previously been appreciated (and does not depend on entanglement, as usually construed); or (ii) the means of avoiding action-at-a-distance in the new cases extends in an obvious way to EPRB, removing action-at-a-distance in these cases, too. There is a third option, viz., to argue that the new cases are strongly disanalogous to EP...

  15. Implementation of GPU-accelerated back projection for EPR imaging.

    Science.gov (United States)

    Qiao, Zhiwei; Redler, Gage; Epel, Boris; Qian, Yuhua; Halpern, Howard

    2015-01-01

    Electron paramagnetic resonance (EPR) Imaging (EPRI) is a robust method for measuring in vivo oxygen concentration (pO2). For 3D pulse EPRI, a commonly used reconstruction algorithm is the filtered backprojection (FBP) algorithm, in which the backprojection process is computationally intensive and may be time consuming when implemented on a CPU. A multistage implementation of the backprojection can be used for acceleration, however it is not flexible (requires equal linear angle projection distribution) and may still be time consuming. In this work, single-stage backprojection is implemented on a GPU (Graphics Processing Units) having 1152 cores to accelerate the process. The GPU implementation results in acceleration by over a factor of 200 overall and by over a factor of 3500 if only the computing time is considered. Some important experiences regarding the implementation of GPU-accelerated backprojection for EPRI are summarized. The resulting accelerated image reconstruction is useful for real-time image reconstruction monitoring and other time sensitive applications.

  16. EPR study of the astaxanthin n-octanoic acid monoester and diester radicals on silica-alumina.

    Science.gov (United States)

    Focsan, A Ligia; Bowman, Michael K; Shamshina, Julia; Krzyaniak, Matthew D; Magyar, Adam; Polyakov, Nikolay E; Kispert, Lowell D

    2012-11-08

    The radical intermediates of the n-octanoic monoester and n-octanoic diester of astaxanthin were detected by pulsed EPR measurements carried out on the UV-produced radicals on silica-alumina artificial matrix and characterized by density functional theory (DFT) calculations. Previous Mims ENDOR for astaxanthin detected the radical cation and neutral radicals formed by proton loss from the C3 (or C3') position and from the methyl groups. Deprotonation of the astaxanthin neutral radical formed at the C3 (or C3') position resulted in a radical anion. DFT calculations for astaxanthin showed that the lowest energy neutral radical forms by proton loss at the C3 (or C3') position of the terminal ring followed by proton loss at the methyl groups of the polyene chain. Contrary to astaxanthin where proton loss can occur at either end of the symmetrical radical, for the diester of astaxanthin, this loss is prevented at the cyclohexene ends and is favored for its methyl groups. The monoester of astaxanthin, however, allows formation of the neutral radical at C3' and prevents its formation at the opposite end where the ester group is attached. At the terminal ring without the ester group attached, migration of proton from hydroxyl group to carbonyl group facilitates resonance stabilization, similarly to already published results for astaxanthin. However, cw EPR shows no evidence of a monoester radical anion formed. This study suggests the different radicals of astaxanthin and its esters that would form in a preferred environment, either hydrophobic or hydrophilic, depending on their structure.

  17. In vivo dosimetry during tangential breast treatment

    Energy Technology Data Exchange (ETDEWEB)

    Heukelom, S.; Lanson, J.H.; Tienhoven, G. van; Mijnheer, B.J. (Nederlands Kanker Inst. ' Antoni van Leeuwenhoekhuis' , Amsterdam (Netherlands))

    1991-12-01

    Three-dimensional (3-D) dose distribution as calculated in clinical practice for tangential breast treatment was verified through in vivo dosimetry. Clinical practice at Netherlands Cancer Institute implies use of 8MV X-ray beams, 2-D treatment planning system, collimator rotation and a limited set of patient data for dose calculations. By positioning diodes at the central beam axes as well as in the periphery of the breast the magnitude of dose values at the isocentre and in points situated in high-dose regions behind the lung could be assessed. The position of diodes was verified by means of an on-line portal imaging device. Reproducibility of these in vivo dose measurements was better than 2% (1SD). This study shows that on the average dose delivery at the isocentre is 2% less at the points behind the lung, 5.7% higher with respect to the calculated dose values. Detailed analysis of these in vivo dosimetry results, based on dose measurements performed with a breast shaped phantom, yielded the magnitudes of errors in predicted dose due to several limitations in dose calculation algorithms and dose calculation procedure. These limitations are each introducing an error of several percent but are compensating each other for the dose calculation at the isocentre. It is concluded that dose distribution in patient for this treatment technique and dose calculation procedure can be predicted with a 2-D treatment planning system in an acceptable way. A more accurate prediction of dose distribution can be performed but requires an estimation of the lack of scatter due to missing tissue, the change in the dose distribution due to oblique incident beams and incorporation of the actual output of the treatment machine in the assessment of the number of monitor units. (author). 28 refs.; 3 figs.; 4 tabs.

  18. Fast neutron activation dosimetry with TLDS

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, D.W.; Moran, P.R.

    1975-01-01

    Fast neutron activation using threshold reactions is the only neutron dosimetry method which offers complete discrimination against gamma-rays and preserves some information about the neutron energy. Conventional activation foil technique requires sensitive radiation detectors to count the decay of the neutron induced activity. For extensive measurements at low neutron fluences, vast outlays of counting equipment are required. TL dosimeters are inexpensive, extremely sensitive radiation detectors. The work of Mayhugh et al. (Proc. Third Int. Conf. on Luminescence Dosimetry, Riso Report 249, 1040, (1971)) showed that CaSO/sub 4/: DyTLDs could be used to measure the integrated dose from the decay of the radioactivity produced in the dosimeters by exposure to thermal neutrons. This neatly combines the activation detector and counter functions in one solid state device. This work has been expanded to fast neutron exposures and other TL phosphors. The reactions /sup 19/F(n, 2n)/sup 18/F, /sup 32/S(n,p)/sup 32/P, /sup 24/Mg(n,p)/sup 24/, and /sup 64/Zn(n,p)/sup 64/Cu were found useful for fast neutron activation in commercial TLDs. As each TLD is its own integrating decay particle counter, many activation measurements can be made at the same time. The subsequent readings of the TL signals can be done serially after the induced radioactivity has decayed, using only one TL reader. The neutron detection sensitivity is limited mainly by the number statistics of the neutron activations. The precision of the neutron measurement is within a factor of two of conventional foil activation for comparable mass detectors. Commercially available TLDs can measure neutron fluences of 10/sup 9/n/cm/sup 2/ with 10 percent precision.

  19. High sensitive radiation detector for radiology dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Valente, M.; Malano, F. [Instituto de Fisica Enrique Gaviola, Oficina 102 FaMAF - UNC, Av. Luis Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina); Molina, W.; Vedelago, J., E-mail: valente@famac.unc.edu.ar [Laboratorio de Investigaciones e Instrumentacion en Fisica Aplicada a la Medicina e Imagenes por Rayos X, Laboratorio 448 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2014-08-15

    Fricke solution has a wide range of applications as radiation detector and dosimetry. It is particularly appreciated in terms of relevant comparative advantages, like tissue equivalence when prepared in aqueous media like gel matrix, continuous mapping capability, dose rate recorded and incident direction independence as well as linear dose response. This work presents the development and characterization of a novel Fricke gel system, based on modified chemical compositions making possible its application in clinical radiology. Properties of standard Fricke gel dosimeter for high dose levels are used as starting point and suitable chemical modifications are introduced and carefully investigated in order to attain high resolution for low dose ranges, like those corresponding to radiology interventions. The developed Fricke gel radiation dosimeter system achieves the expected typical dose dependency, actually showing linear response in the dose range from 20 up to 4000 mGy. Systematic investigations including several chemical compositions are carried out in order to obtain a good enough dosimeter response for low dose levels. A suitable composition among those studied is selected as a good candidate for low dose level radiation dosimetry consisting on a modified Fricke solution fixed to a gel matrix containing benzoic acid along with sulfuric acid, ferrous sulfate, xylenol orange and ultra-pure reactive grade water. Dosimeter samples are prepared in standard vials for its in phantom irradiation and further characterization by spectrophotometry measuring visible light transmission and absorbance before and after irradiation. Samples are irradiated by typical kV X-ray tubes and calibrated Farmer type ionization chamber is used as reference to measure dose rates inside phantoms in at vials locations. Once sensitive material composition is already optimized, dose-response curves show significant improvement regarding overall sensitivity for low dose levels. According to

  20. Personal Dosimetry Enhancement for Underground Workplaces

    Directory of Open Access Journals (Sweden)

    L. Thinová

    2005-01-01

    Full Text Available Personal dosimetry for underground workers mainly concerns measurement of the concentration of radon (and its daughters and the correct application of the data in dose calculation, using a biokinetic model for lung dosimetry. A conservative approach for estimating the potential dose in caves (or underground is based on solid state alpha track detector measurements. The obtained dataset is converted into an annual effective dose in agreement with the ICRP recommendations using the “cave factor”, the value of which depends on the spectrum of aerosol particles, or on the proportional representation of the unattached and the attached fraction and on the equilibrium factor. The main difference between apartments and caves is the absence of aerosol sources, high humidity, low ventilation rate and the uneven surface in caves. A more precisely determined dose value would have a significant impact on radon remedies or on restricting the time workers stay underground. In order to determine  how the effective dose is calculated, it is necessary to divide these areas into distinct categories by the following measuring procedures: continual radon measurement (to capture the differences in EERC between working hours and night-time, and also between daily and seasonal radon concentration variations; regular measurements of radon and its daughters to estimate the equilibrium factor and the presence of 218Po; regular indoor air flow measurements to study the location of the radon supply and its transfer among individual areas of the cave; natural radioactive element content evaluation in subsoils and in water inside/outside, a study of the radon sources in the cave; aerosol particle-size spectrum measurements to determine the free fraction; monitoring the behaviour of guides and workers to record the actual time spent in the cave, in relation to the continuously monitored levels of Rn concentration. 

  1. Latest developments in silica fibre luminescence dosimetry

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

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

  2. Dosimetry of low-energy beta radiation

    Energy Technology Data Exchange (ETDEWEB)

    Borg, J.

    1996-08-01

    Useful techniques and procedures for determination of absorbed doses from exposure in a low-energy {beta} radiation field were studied and evaluated in this project. The four different techniques included were {beta} spectrometry, extrapolation chamber dosimetry, Monte Carlo (MC) calculations, and exoelectron dosimetry. As a typical low-energy {beta} radiation field a moderated spectrum from a {sup 14}C source (E{sub {beta}},{sub max} =156 keV) was chosen for the study. The measured response of a Si(Li) detector to photons (bremsstrahlung) showed fine agreement with the MC calculated photon response, whereas the difference between measured and MC calculated responses to electrons indicates an additional dead layer thickness of about 12 {mu}m in the Si(Li) detector. The depth-dose profiles measured with extrapolation chambers at two laboratories agreed very well, and it was confirmed that the fitting procedure previously reported for {sup 147}Pm depth-dose profiles is also suitable for {beta} radiation from {sup 14}C. An increasing difference between measured and MC calculated dose rates for increasing absorber thickness was found, which is explained by limitations of the EGS4 code for transport of very low-energy electrons (below 10-20 keV). Finally a study of the thermally stimulated exoelectron emission (TSEE) response of BeO thin film dosemeters to {beta} radiation for radiation fields with maximum {beta} energies ranging from 67 keV to 2.27 MeV is reported. For maximum {beta} energies below approximately 500 keV, a decrease in the response amounting to about 20% was observed. It is thus concluded that a {beta} dose higher than about 10 {mu}Gy can be measured with these dosemeters to within 0 to -20% independently of the {beta}energy for E{sub {beta}},{sub max} values down to 67 keV. (au) 12 tabs., 38 ills., 71 refs.

  3. Review of the near-earth space radiation dosimetry

    Science.gov (United States)

    Guo, Jianming; Chen, Xiaoqian; Li, Shiyou

    2016-07-01

    The near-earth space radiation environment has a great effect to the spacecraft and maybe do harm to the astronaut's health. Thus, how to measure the radiation has become a serious challenge. In order to provide sufficient protection both for astronauts and for instruments on-board, dose equivalent and linear energy transfer should be measured instead of merely measuring total radiation dose. This paper reviews the methods of radiation measurement and presents a brief introduction of dosimetry instruments. The method can be divided into two different kinds, i.e., positive dosimetry and passive dosimetry. The former usually includes electronic devices which can be used for data storage and can offer simultaneous monitoring on space radiation. The passive dosimetry has a much simple structure, and need extra operation after on-orbit missions for measuring. To get more reliable data of radiation dosimetry, various instruments and methods had been applied in the spacecrafts and the manned spacecrafts in particular. The outlook of the development in the space radiation dosimetry measurement is also presented.

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

    Energy Technology Data Exchange (ETDEWEB)

    Al-Karmi, Anan M.; Zraiqat, Fadi [Physics Department, King Fahd University of Petroleum & Minerals, Dhahran 31261 (Saudi Arabia)

    2015-06-15

    Purpose: The objective of this study was evaluation of accuracy of pure alanine dosimeters measuring intensity-modulated radiation therapy (IMRT) dose distributions in a thorax phantom. Methods: Alanine dosimeters were prepared in the form of 110 mg pure L-α-alanine powder filled into clear tissue-equivalent polymethylmethacrylate (PMMA) plastic tubes with the dimensions 25 mm length, 3 mm inner diameter, and 1 mm wall thickness. A dose-response calibration curve was established for the alanine by placing the dosimeters at 1.5 cm depth in a 30×30×30 cm{sup 3} solid water phantom and then irradiating on a linac with 6 MV photon beam at 10×10 cm{sup 2} field size to doses ranging from 1 to 5 Gy. Electron paramagnetic resonance (EPR) spectroscopy was used to determine the absorbed dose in alanine. An IMRT treatment plan was designed for a commercial heterogeneous CIRS thorax phantom and the dose values were calculated at three different points located in tissue, lung, and bone equivalent materials. A set of dose measurements was carried out to compare measured and calculated dose values by placing the alanine dosimeters at those selected locations inside the thorax phantom and delivering the IMRT to the phantom. Results: The alanine dose measurements and the IMRT plan dose calculations were found to be in agreement within ±2%. Specifically, the deviations were −0.5%, 1.3%, and −1.7% for tissue, lung, and bone; respectively. The slightly large deviations observed for lung and bone may be attributed to tissue inhomogeneity, steep dose gradients in these regions, and uncontrollable changes in spectrometer conditions. Conclusion: The results described herein confirmed that pure alanine dosimeter was suitable for in-phantom dosimetry of IMRT beams because of its high sensitivity and acceptable accuracy. This makes the dosimeter a promising option for quality control of the therapeutic beams, complementing the commonly used ionization chambers, TLDs, and films.

  5. Automated DICOM metadata and volumetric anatomical information extraction for radiation dosimetry

    Science.gov (United States)

    Papamichail, D.; Ploussi, A.; Kordolaimi, S.; Karavasilis, E.; Papadimitroulas, P.; Syrgiamiotis, V.; Efstathopoulos, E.

    2015-09-01

    Patient-specific dosimetry calculations based on simulation techniques have as a prerequisite the modeling of the modality system and the creation of voxelized phantoms. This procedure requires the knowledge of scanning parameters and patients’ information included in a DICOM file as well as image segmentation. However, the extraction of this information is complicated and time-consuming. The objective of this study was to develop a simple graphical user interface (GUI) to (i) automatically extract metadata from every slice image of a DICOM file in a single query and (ii) interactively specify the regions of interest (ROI) without explicit access to the radiology information system. The user-friendly application developed in Matlab environment. The user can select a series of DICOM files and manage their text and graphical data. The metadata are automatically formatted and presented to the user as a Microsoft Excel file. The volumetric maps are formed by interactively specifying the ROIs and by assigning a specific value in every ROI. The result is stored in DICOM format, for data and trend analysis. The developed GUI is easy, fast and and constitutes a very useful tool for individualized dosimetry. One of the future goals is to incorporate a remote access to a PACS server functionality.

  6. CW- and pulsed-EPR of carbonaceous matter in primitive meteorites: solving a lineshape paradox.

    Science.gov (United States)

    Delpoux, Olivier; Gourier, Didier; Binet, Laurent; Vezin, Hervé; Derenne, Sylvie; Robert, François

    2008-05-01

    Insoluble organic matter (IOM) of Orgueil and Tagish Lake meteorites are studied by CW-EPR and pulsed-EPR spectroscopies. The EPR line is due to polycyclic paramagnetic moieties concentrated in defect-rich regions of the IOM, with concentrations of the order of 4x10(19) spin/g. CW-EPR reveals two types of paramagnetic defects: centres with S=1/2, and centres with S=0 ground state and thermally accessible triple state S=1. In spite of the Lorentzian shape of the EPR and its narrowing upon increasing the spin concentration, the EPR line is not in the exchange narrowing regime as previously deduced from multi-frequency CW-EPR [L. Binet, D. Gourier, Appl. Magn. Reson. 30 (2006) 207-231]. It is inhomogeneously broadened as demonstrated by the presence of nuclear modulations in the spin-echo decay. The line narrowing, similar to an exchange narrowing effect, is the result of an increasing contribution of the narrow line of the triplet state centres in addition to the broader line of doublet states. Hyperfine sublevel correlation spectroscopy (HYSCORE) of hydrogen and (13)C nuclei indicates that IOM* centres are small polycyclic moieties that are moderately branched with aliphatic chains, as shown by the presence of aromatic hydrogen atoms. On the contrary the lack of such aromatic hydrogen in triplet states suggests that these radicals are most probably highly branched. Paramagnetic centres are considerably enriched in deuterium, with D/H approximately 1.5+/-0.5x10(-2) of the order of values existing in interstellar medium.

  7. Influence of experimental parameters on sonochemistry dosimetries: KI oxidation, Fricke reaction and H{sub 2}O{sub 2} production

    Energy Technology Data Exchange (ETDEWEB)

    Merouani, Slimane [Laboratory of Environmental Engineering, Department of Process Engineering, Faculty of Engineering, University of Annaba, P.O. Box 12, 23000 Annaba (Algeria); Hamdaoui, Oualid, E-mail: ohamdaoui@yahoo.fr [Laboratory of Environmental Engineering, Department of Process Engineering, Faculty of Engineering, University of Annaba, P.O. Box 12, 23000 Annaba (Algeria); Saoudi, Fethi; Chiha, Mahdi [Laboratory of Environmental Engineering, Department of Process Engineering, Faculty of Engineering, University of Annaba, P.O. Box 12, 23000 Annaba (Algeria)

    2010-06-15

    Central events of the ultrasonic action are the cavitation bubbles that can be considered as microreactors. Adiabatic collapse of cavitation bubbles leads to the formation of reactive species such as hydroxyl radicals ({center_dot}OH), hydrogen peroxide (H{sub 2}O{sub 2}) and hydroperoxyl radicals (HOO{center_dot}). Several chemical methods were used to detect the production of these reactive moieties in sonochemistry. In this work, the influence of several operational parameters on the sonochemistry dosimetries namely KI oxidation, Fricke reaction and H{sub 2}O{sub 2} production using 300 kHz ultrasound was investigated. The main experimental parameters showing significant effect in KI oxidation dosimetry were initial KI concentration, acoustic power and pH. The solution temperature showed restricted influence on KI oxidation. The acoustic power and liquid temperature highly affected Fricke reaction dosimetry. Operational conditions having important influence on H{sub 2}O{sub 2} formation were acoustic power, solution temperature and pH. For the three tested dosimetries, the sonochemical efficiency was independent of liquid volume.

  8. Radiation protection dosimetry in medicine - Report of the working group n.9 of the European radiation dosimetry group (EURADOS) - coordinated network for radiation dosimetry (CONRAD - contract EC N) fp6-12684; Dosimetrie pour la radioprotection en milieu medical - rapport du groupe de travail n. 9 du European radiation dosimetry group (EURADOS) - coordinated netword for radiation dosimetry (CONRAD - contrat CE fp6-12684)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    This report present the results achieved within the frame of the work the WP 7 (Radiation Protection Dosimetry of Medical Staff) of the coordination action CONRAD (Coordinated Network for Radiation Dosimetry) funded through the 6. EU Framework Program. This action was coordinated by EURADOS (European Radiation Dosimetry Group). EURADOS is an organization founded in 1981 to advance the scientific understanding and the technical development of the dosimetry of ionising radiation in the fields of radiation protection, radiobiology, radiation therapy and medical diagnosis by promoting collaboration between European laboratories. WP7 coordinates and promotes European research for the assessment of occupational exposures to staff in therapeutic and diagnostic radiology workplaces. Research is coordinated through sub-groups covering three specific areas: 1. Extremity dosimetry in nuclear medicine and interventional radiology: this sub-group coordinates investigations in the specific fields of the hospitals and studies of doses to different parts of the hands, arms, legs and feet; 2. Practice of double dosimetry: this sub-group reviews and evaluates the different methods and algorithms for the use of dosemeters placed above and below lead aprons in large exposure during interventional radiology procedures, especially to determine effective doses to cardiologists during cardiac catheterization; and 3. Use of electronic personal dosemeters in interventional radiology: this sub-group coordinates investigations in laboratories and hospitals, and intercomparisons with passive dosemeters with the aim to enable the formulation of standards. (authors)

  9. EPR spectroscopy of a clinically active (1:2) copper(II)-histidine complex used in the treatment of Menkes disease: a Fourier transform analysis of a fluid CW-EPR spectrum.

    Science.gov (United States)

    Gala, Lukas; Lawson, Michael; Jomova, Klaudia; Zelenicky, Lubomir; Congradyova, Andrea; Mazur, Milan; Valko, Marian

    2014-01-15

    Redox active transition metal ions (e.g., iron and copper) have been implicated in the etiology of many oxidative stress-related diseases including also neurodegenerative disorders. Unbound copper can catalyze formation of reactive oxygen species (hydroxyl radicals) via Fenton reaction/Haber-Weiss chemistry and therefore, under physiological conditions, free copper is potentially toxic and very rarely exists inside cells. Copper(II) bound to the aminoacid L-histidine represents a species discovered in blood in the mid 60s and since then extensive research on this complex was carried out. Copper bound to L-histidine represents an exchangeable pool of copper(II) in equilibrium with the most abundant blood plasma protein, human serum albumin. The structure of this complex, in aqueous solution, has been a subject of many studies and reviews, however without convincing success. The significance of the (1:2) copper(II)-L-histidine complex at physiological pH documents its therapeutic applications in the treatment of Menkes disease and more recently in the treatment of infantile hypertrophic cardioencephalomyopathy. While recently the (1:2) Cu(II)-L-His complex has been successfully crystallized and the crystal structure was solved by X-ray diffraction, the structure of the complex in fluid solution at physiological pH is not satisfactorily known. The aim of this paper is to study the (1:2) Cu(II)-L-histidine complex at low temperatures by X-band and S-band EPR spectroscopy and at physiological pH at room temperature by Fourier transform CW-EPR spectroscopy.

  10. EPR Spectroscopy of a Clinically Active (1:2 Copper(II-Histidine Complex Used in the Treatment of Menkes Disease: A Fourier Transform Analysis of a Fluid CW-EPR Spectrum

    Directory of Open Access Journals (Sweden)

    Lukas Gala

    2014-01-01

    Full Text Available Redox active transition metal ions (e.g., iron and copper have been implicated in the etiology of many oxidative stress-related diseases including also neurodegenerative disorders. Unbound copper can catalyze formation of reactive oxygen species (hydroxyl radicals via Fenton reaction/Haber–Weiss chemistry and therefore, under physiological conditions, free copper is potentially toxic and very rarely exists inside cells. Copper(II bound to the aminoacid L-histidine represents a species discovered in blood in the mid 60s and since then extensive research on this complex was carried out. Copper bound to L-histidine represents an exchangeable pool of copper(II in equilibrium with the most abundant blood plasma protein, human serum albumin. The structure of this complex, in aqueous solution, has been a subject of many studies and reviews, however without convincing success. The significance of the (1:2 copper(II-L-histidine complex at physiological pH documents its therapeutic applications in the treatment of Menkes disease and more recently in the treatment of infantile hypertrophic cardioencephalomyopathy. While recently the (1:2 Cu(II-L-His complex has been successfully crystallized and the crystal structure was solved by X-ray diffraction, the structure of the complex in fluid solution at physiological pH is not satisfactorily known. The aim of this paper is to study the (1:2 Cu(II-L-histidine complex at low temperatures by X-band and S-band EPR spectroscopy and at physiological pH at room temperature by Fourier transform CW-EPR spectroscopy.

  11. SIXTH ERDA WORKSHOP ON PERSONNEL NEUTRON DOSIMETRY

    Energy Technology Data Exchange (ETDEWEB)

    Vallario, E. J.; Hankins, D. E.; Bramson, P. E.

    1977-07-11

    This workshop was the sixth of a series and was held on July 11 and 12, 1977, at the Oak Ridge National Laboratory in Oak Ridge, Tennessee. Those presenting papers at the Sixth Workshop prepared summary reports of their recent work for inclusion in this document. The reports are reproduced here as submitted by the participants, with only minor editing. This year's Workshop took a decidedly international flavor, with participants from seven countries in addition to the United States. The significance of this group's contributions has raised the possibility that the next Neutron Dosimetry Workshop may be held in Europe. Of particular interest at the Workshop was the keynote address by Dr. Harald Rossi. He commented that there is evidence that 1) accepted values of RBE for low absorbed doses of neutrons may be low by an order of magnitude or more and 2) the risk of leukemia is significant at 0.5 rad to the bone narrow. A reduction of the limit for permissible neutron exposure, which could result from consideration of this information, would necessitate major improvements in our "middle ages" neutron dosimetry. A number of participants reported conversions to thermoluminescent dosimeter (TLD) systems. This move has not been unanimous, however, as there were several reports of apparently satisfactory fission fragment, activation foil, and NTA film dosimeters. While thementionof NTA film resulted in the usual discussion of energy cut off and humidity effects, it seems the use of NTA in accelerator environments still has some merit. Discussion of fission fragment dosimeters centered around track etching techniques, which have shown some improvement. Of particular interest was Tommasino's report on the use of polycarbonate centrifuge tubes as the sensitive element. Thermally stimulated exoelectron emission (TSEE), never very popular for personnel dosimetry, has lost additional ground with the report that the neutron/gamma response ratio is much less than

  12. A probabilistic gastrointestinal tract dosimetry model

    Science.gov (United States)

    Huh, Chulhaeng

    In internal dosimetry, the tissues of the gastrointestinal (GI) tract represent one of the most radiosensitive organs of the body with the hematopoietic bone marrow. Endoscopic ultrasound is a unique tool to acquire in-vivo data on GI tract wall thicknesses of sufficient resolution needed in radiation dosimetry studies. Through their different echo texture and intensity, five layers of differing echo patterns for superficial mucosa, deep mucosa, submucosa, muscularis propria and serosa exist within the walls of organs composing the alimentary tract. Thicknesses for stomach mucosa ranged from 620 +/- 150 mum to 1320 +/- 80 mum (total stomach wall thicknesses from 2.56 +/- 0.12 to 4.12 +/- 0.11 mm). Measurements made for the rectal images revealed rectal mucosal thicknesses from 150 +/- 90 mum to 670 +/- 110 mum (total rectal wall thicknesses from 2.01 +/- 0.06 to 3.35 +/- 0.46 mm). The mucosa thus accounted for 28 +/- 3% and 16 +/- 6% of the total thickness of the stomach and rectal wall, respectively. Radiation transport simulations were then performed using the Monte Carlo N-particle transport code (MCNP) 4C transport code to calculate S values (Gy/Bq-s) for penetrating and nonpenetrating radiations such as photons, beta particles, conversion electrons and auger electrons of selected nuclides, I123, I131, Tc 99m and Y90 under two source conditions: content and mucosa sources, respectively. The results of this study demonstrate generally good agreement with published data for the stomach mucosa wall. The rectal mucosa data are consistently higher than published data compared with the large intestine due to different radiosensitive cell thicknesses (350 mum vs. a range spanning from 149 mum to 729 mum) and different geometry when a rectal content source is considered. Generally, the ICRP models have been designed to predict the amount of radiation dose in the human body from a "typical" or "reference" individual in a given population. The study has been performed to

  13. Cooling rate effects in thermoluminescence dosimetry grade lithium flouride. Implications for practical dosimetry.

    Science.gov (United States)

    Mason, E W; McKinlay, A F; Clark, I

    1976-01-01

    A systematic investigation of the effects of cooling rates in the range of 10(-1) to 2 X 10(5) degrees C min-1 applied to TLD-700, LiF thermoluminescence dosemeters has shown that the 'transfer sensitivity' effect observed by Booth, Johnson and Attix (1972) is only of importance for cooling rates greater than 10(3) degrees C min-1. Although it is concluded that for practical dosimetry purposes the effect may be ignored it is not clear why Booth et al. observed such large changes and until this discrepancy is explained it is recommended that a low temperature pre-irradiation anneal should be used.

  14. Radiation sensitivity and EPR dosimetric potential of gallic acid and its esters

    Science.gov (United States)

    Tuner, Hasan; Oktay Bal, M.; Polat, Mustafa

    2015-02-01

    In the preset work the radiation sensitivities of Gallic Acid anhydrous and monohydrate, Octyl, Lauryl, and Ethyl Gallate (GA, GAm, OG, LG, and EG) were investigated in the intermediate (0.5-20 kGy) and low radiation (<10 Gy) dose range using Electron Paramagnetic Resonance (EPR) spectroscopy. While OG, LG, and EG are presented a singlet EPR spectra, their radiation sensitivity found to be very different in the intermediate dose range. At low radiation dose range (<10 Gy) only LG is found to be present a signal that easily distinguished from the noise signals. The intermediate and low dose range radiation sensitivities are compared using well known EPR dosimeter alanine. The radiation yields (G) of the interested material were found to be 1.34×10-2, 1.48×10-2, 4.14×10-2, and 6.03×10-2, 9.44×10-2 for EG, GA, GAm, OG, and LG, respectively at the intermediate dose range. It is found that the simple EPR spectra and the noticeable EPR signal of LG make it a promising dosimetric material to be used below 10 Gy of radiation dose.

  15. Identification of slow relaxing spin components by pulse EPR techniques in graphene-related materials

    Directory of Open Access Journals (Sweden)

    Antonio Barbon

    2017-01-01

    Full Text Available Electron Paramagnetic Resonance (EPR is a powerful technique that is suitable to study graphene-related materials. The challenging ability requested to the spectroscopy is its capability to resolve the variety of structures, relatively similar, that are obtained in materials produced through different methods, but that also coexist inside a single sample. In general, because of the intrinsic inhomogeneity of the samples, the EPR spectra are therefore a superposition of spectra coming from different structures. We show that by pulse EPR techniques (echo-detected EPR, ESEEM and Mims ENDOR we can identify and characterize species with slow spin relaxing properties. These species are generally called molecular states, and are likely small pieces of graphenic structures of limited dimensions, thus conveniently described by a molecular approach. We have studied commercial reduced graphene oxide and chemically exfoliated graphite, which are characterized by different EPR spectra. Hyperfine spectroscopies enabled us to characterize the molecular components of the different materials, especially in terms of the interaction of the unpaired electrons with protons (number of protons and hyperfine coupling constants. We also obtained useful precious information about extent of delocalization of the molecular states.

  16. DFT calculations of EPR parameters for copper(II)-exchanged zeolites using cluster models.

    Science.gov (United States)

    Ames, William M; Larsen, Sarah C

    2010-01-14

    The coordination environment of Cu(II) in hydrated copper-exchanged zeolites was explored through the use of density functional theory (DFT) calculations of EPR parameters. Extensive experimental EPR data are available in the literature for hydrated copper-exchanged zeolites. The copper complex in hydrated copper-exchanged zeolites was previously proposed to be [Cu(H(2)O)(5)OH](+) based on empirical trends in tetragonal model complex EPR data. In this study, calculated EPR parameters for the previously proposed copper complex, [Cu(H(2)O)(5)OH](+), were compared to model complexes in which Cu(II) was coordinated to small silicate or aluminosilicate clusters as a first approximation of the impact of the zeolitic environment on the copper complex. Interpretation of the results suggests that Cu(II) is coordinated or closely associated with framework oxygen atoms within the zeolite structure. Additionally, it is proposed that the EPR parameters are dependent on the Si/Al ratio of the parent zeolite.

  17. A special JMR issue: Methodological advances in EPR spectroscopy and imaging

    Science.gov (United States)

    2017-07-01

    Since about five decades, EPR spectroscopy provides important insights into the electronic structure of metalloproteins and transition-metal based catalysts. Somewhat later this spectroscopy was also applied to the study of electron transfer processes, often in radical enzymes. The study of diamagnetic proteins and nucleic acids with site-directed spin labeling (SDSL) techniques became really popular in the 1990s and early in the new millennium. The same applies to applications of pulsed EPR techniques to metalloproteins, although the pioneering work in this field by Mims and Peisach dates back to the early 1970s. Pulsed dipolar spectroscopy for the measurement of distance distributions in the nanometer range has become the major EPR-based tool in structural biology during the past 15 years and is still expanding its scope. EPR (or ESR) imaging may appear to be overshadowed by (nuclear) MRI, as it has not yet found clinical application. However, development of EPR-based imaging modalities has recently gained much momentum as they can provide information that is inaccessible by any established imaging technology.

  18. Direct in vivo interaction of the antibiotic primycin with the plasma membrane of Candida albicans: an EPR study.

    Science.gov (United States)

    Virág, Eszter; Belagyi, Joseph; Gazdag, Zoltán; Vágvölgyi, Csaba; Pesti, Miklós

    2012-01-01

    The direct interaction of the antibiotic primycin with the plasma membrane was investigated by employing the well-characterized ergosterol-producing, amphotericin B-sensitive parental Candida albicans strain 33erg(+) and its ergosterol-less amphotericin B-resistant plasma membrane mutant erg-2. The growth inhibition concentration in shaken liquid medium was 64 μgml(-1) for 33erg(+) and 128 μgml(-1) for erg-2, suggesting that the plasma membrane composition influences the mode of action of primycin. To determine the primycin-induced changes in the plasma membrane dynamic, electron paramagnetic resonance (EPR) spectroscopy methods were used, the spin-labeled fatty acid 5-(4,4-dimethyloxazolidine-N-oxyl)stearic acid) being applied for the in vivo measurements. The phase transition temperatures of untreated strain 33erg(+) and its mutant erg-2 were 12.5°C and 11°C, respectively. After 128 μgml(-1) primycin treatment, these values increased to 17.5°C and 16°C, revealing a significant reduction in the phospholipid flexibility. Saturation transfer EPR measurements demonstrated that, the rotational correlation times of the spin label molecule for the control samples of 33erg(+) and erg-2 were 60 ns and 100 ns. These correlation times gradually decreased on the addition of increasing primycin concentrations, reaching 8 μs and 1 μs. The results indicate the plasma membrane "rigidizing" effect of primycin, a feature that may stem from its ability to undergo complex formation with membrane constituent fatty acid molecules, causing alterations in the structures of phospholipids in the hydrophobic surface near the fatty acid chain region. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Hanford External Dosimetry Technical Basis Manual PNL-MA-842

    Energy Technology Data Exchange (ETDEWEB)

    Rathbone, Bruce A.

    2010-04-01

    The Hanford External Dosimetry Technical Basis Manual PNL-MA-842 documents the design and implementation of the external dosimetry system used at the U.S. Department of Energy (DOE) Hanford site. The manual describes the dosimeter design, processing protocols, dose calculation methodology, radiation fields encountered, dosimeter response characteristics, limitations of dosimeter design under field conditions, and makes recommendations for effective use of the dosimeters in the field. The manual describes the technical basis for the dosimetry system in a manner intended to help ensure defensibility of the dose of record at Hanford and to demonstrate compliance with requirements of 10 CFR 835, the DOE Laboratory Accreditation Program, the DOE Richland Operations Office, DOE Office of River Protection, DOE Pacific Northwest Office of Science, and Hanford’s DOE contractors. The dosimetry system is operated by the Pacific Northwest National Laboratory (PNNL) Hanford External Dosimetry Program which provides dosimetry services to PNNL and all Hanford contractors. The primary users of this manual are DOE and DOE contractors at Hanford using the dosimetry services of PNNL. Development and maintenance of this manual is funded directly by DOE and DOE contractors. Its contents have been reviewed and approved by DOE and DOE contractors at Hanford through the Hanford Personnel Dosimetry Advisory Committee which is chartered and chaired by DOE-RL and serves as means of coordinating dosimetry practices across contractors at Hanford. This manual was established in 1996. Since its inception, it has been revised many times and maintained by PNNL as a controlled document with controlled distribution. The first revision to be released through PNNL’s Electronic Records & Information Capture Architecture database was designated Revision 0. Revision numbers that are whole numbers reflect major revisions typically involving significant changes to all chapters in the document. Revision

  20. Hanford External Dosimetry Technical Basis Manual PNL-MA-842

    Energy Technology Data Exchange (ETDEWEB)

    Rathbone, Bruce A.

    2011-04-04

    The Hanford External Dosimetry Technical Basis Manual PNL-MA-842 documents the design and implementation of the external dosimetry system used at the U.S. Department of Energy (DOE) Hanford site. The manual describes the dosimeter design, processing protocols, dose calculation methodology, radiation fields encountered, dosimeter response characteristics, limitations of dosimeter design under field conditions, and makes recommendations for effective use of the dosimeters in the field. The manual describes the technical basis for the dosimetry system in a manner intended to help ensure defensibility of the dose of record at Hanford and to demonstrate compliance with requirements of 10 CFR 835, the DOE Laboratory Accreditation Program, the DOE Richland Operations Office, DOE Office of River Protection, DOE Pacific Northwest Office of Science, and Hanford’s DOE contractors. The dosimetry system is operated by the Pacific Northwest National Laboratory (PNNL) Hanford External Dosimetry Program which provides dosimetry services to PNNL and all Hanford contractors. The primary users of this manual are DOE and DOE contractors at Hanford using the dosimetry services of PNNL. Development and maintenance of this manual is funded directly by DOE and DOE contractors. Its contents have been reviewed and approved by DOE and DOE contractors at Hanford through the Hanford Personnel Dosimetry Advisory Committee which is chartered and chaired by DOE-RL and serves as means of coordinating dosimetry practices across contractors at Hanford. This manual was established in 1996. Since its inception, it has been revised many times and maintained by PNNL as a controlled document with controlled distribution. The first revision to be released through PNNL’s Electronic Records & Information Capture Architecture database was designated Revision 0. Revision numbers that are whole numbers reflect major revisions typically involving significant changes to all chapters in the document. Revision

  1. Dosimetry in nuclear power plants; Dosimetria en centrales nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Lastra B, J. A. [CFE, Central Laguna Verde, Km. 42.5 Carretera Cardel-Nautla, Veracruz (Mexico)

    2008-12-15

    To control the occupationally exposed personnel dose working at the Laguna Verde nuclear power plant, two types of dosemeters are used, the thermoluminescent (TLD) which is processed monthly, and the direct reading dosemeter that is electronic and works as daily control of personal dose. In the case of the electronic dosemeters of direct reading conventional, the readings and dose automatic registers and the user identity to which he was assigned to each dosemeter was to carry out the restricted area exit. In activities where the ionizing radiation sources are not fully characterized, it is necessary to relocate the personal dosemeter or assigned auxiliary dosemeters (TLDs and electronics) to determine the dose received by the user to both whole body and in any specific area of it. In jobs more complicated are used a tele dosimetry system where the radiation protection technician can be monitoring the user dose to remote control, the data transmission is by radio. The dosimetry activities are documented in procedures that include dosemeter inventories realization, the equipment and dosemeters calibration, the dosimetry quality control and the discrepancies investigation between the direct reading and TLD systems. TLD dosimetry to have technical expertise in direct and indirect dosimetry and two technicians in TLD dosimetry; electronic dosimetry to have 4 calibration technicians. For the electronic dosemeters are based on a calibrator source of Cesium-137. TLD dosemeters to have an automatic radiator, an automatic reader which can read up to 100 TLD dosemeters per hour and a semiautomatic reader. To keep the equipment under a quality process was development a process of initial entry into service and carried out a periodic verification of the heating cycles. It also has a maintenance contract for the equipment directly with the manufacturer to ensure their proper functioning. The vision in perspective of the dosimetry services of Laguna Verde nuclear power plant

  2. Hanford External Dosimetry Technical Basis Manual PNL-MA-842

    Energy Technology Data Exchange (ETDEWEB)

    Rathbone, Bruce A.

    2007-03-12

    The Hanford External Dosimetry Technical Basis Manual PNL-MA-842 documents the design and implementation of the external dosimetry system used at Hanford. The manual describes the dosimeter design, processing protocols, dose calculation methodology, radiation fields encountered, dosimeter response characteristics, limitations of dosimeter design under field conditions, and makes recommendations for effective use of the dosimeters in the field. The manual describes the technical basis for the dosimetry system in a manner intended to help ensure defensibility of the dose of record at Hanford and to demonstrate compliance with 10 CFR 835, DOELAP, DOE-RL, ORP, PNSO, and Hanford contractor requirements. The dosimetry system is operated by PNNL’s Hanford External Dosimetry Program (HEDP) which provides dosimetry services to all Hanford contractors. The primary users of this manual are DOE and DOE contractors at Hanford using the dosimetry services of PNNL. Development and maintenance of this manual is funded directly by DOE and DOE contractors. Its contents have been reviewed and approved by DOE and DOE contractors at Hanford through the Hanford Personnel Dosimetry Advisory Committee (HPDAC) which is chartered and chaired by DOE-RL and serves as means of coordinating dosimetry practices across contractors at Hanford. This manual was established in 1996. Since inception, it has been revised many times and maintained by PNNL as a controlled document with controlled distribution. Rev. 0 marks the first revision to be released through PNNL’s Electronic Records & Information Capture Architecture (ERICA) database. Revision numbers that are whole numbers reflect major revisions typically involving changes to all chapters in the document. Revision numbers that include a decimal fraction reflect minor revisions, usually restricted to selected chapters or selected pages in the document. Revision Log: Rev. 0 (2/25/2005) Major revision and expansion. Rev. 0.1 (3/12/2007) Minor

  3. Macroscopic to Microscopic Scales of Particulate Dosimetry: From Source to Fate in the Body

    Science.gov (United States)

    Additional perspective with regards to particle dosimetry is achieved by exploring dosimetry across a range of scales from macroscopic to microscopic in scope. Typically, one thinks of dosimetry as what happens when a particle is inhaled, where it is deposited, and how it is clea...

  4. Trends of personal dosimetry at atomic power plants

    Energy Technology Data Exchange (ETDEWEB)

    Yamamura, Seini [Fuji Electric Co. Ltd., Tokyo Factory, Radiation Equipment Department, Tokyo (Japan)

    1998-12-31

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

  5. Millimeter wave dosimetry of human skin.

    Science.gov (United States)

    Alekseev, S I; Radzievsky, A A; Logani, M K; Ziskin, M C

    2008-01-01

    To identify the mechanisms of biological effects of mm waves it is important to develop accurate methods for evaluating absorption and penetration depth of mm waves in the epidermis and dermis. The main characteristics of mm wave skin dosimetry were calculated using a homogeneous unilayer model and two multilayer models of skin. These characteristics included reflection, power density (PD), penetration depth (delta), and specific absorption rate (SAR). The parameters of the models were found from fitting the models to the experimental data obtained from measurements of mm wave reflection from human skin. The forearm and palm data were used to model the skin with thin and thick stratum corneum (SC), respectively. The thin SC produced little influence on the interaction of mm waves with skin. On the contrary, the thick SC in the palm played the role of a matching layer and significantly reduced reflection. In addition, the palmar skin manifested a broad peak in reflection within the 83-277 GHz range. The viable epidermis plus dermis, containing a large amount of free water, greatly attenuated mm wave energy. Therefore, the deeper fat layer had little effect on the PD and SAR profiles. We observed the appearance of a moderate SAR peak in the therapeutic frequency range (42-62 GHz) within the skin at a depth of 0.3-0.4 mm. Millimeter waves penetrate into the human skin deep enough (delta = 0.65 mm at 42 GHz) to affect most skin structures located in the epidermis and dermis.

  6. Artificial neural networks in neutron dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R.; Hernandez D, V.M.; Manzanares A, E.; Mercado, G.A.; Perales M, W.A.; Robles R, J.A. [Unidades Academicas de Estudios Nucleares, UAZ, A.P. 336, 98000 Zacatecas (Mexico); Gallego, E.; Lorente, A. [Depto. de Ingenieria Nuclear, Universidad Politecnica de Madrid, (Spain)

    2005-07-01

    An artificial neural network has been designed to obtain the neutron doses using only the Bonner spheres spectrometer's count rates. Ambient, personal and effective neutron doses were included. 187 neutron spectra were utilized to calculate the Bonner count rates and the neutron doses. The spectra were transformed from lethargy to energy distribution and were re-binned to 31 energy groups using the MCNP 4C code. Re-binned spectra, UTA4 response matrix and fluence-to-dose coefficients were used to calculate the count rates in Bonner spheres spectrometer and the doses. Count rates were used as input and the respective doses were used as output during neural network training. Training and testing was carried out in Mat lab environment. The artificial neural network performance was evaluated using the {chi}{sup 2}- test, where the original and calculated doses were compared. The use of Artificial Neural Networks in neutron dosimetry is an alternative procedure that overcomes the drawbacks associated in this ill-conditioned problem. (Author)

  7. IMBA Expert: internal dosimetry made simple.

    Science.gov (United States)

    Birchall, A; Puncher, M; James, A C; Marsh, J W; Jarvis, N S; Peace, M S; Davis, K; King, D J

    2003-01-01

    In 1997, a collaboration between British Nuclear Fuels plc (BNFL), Westlakes Research Institute and NRPB started, with the aim of producing IMBA (Integrated Modules for Bioassay Analysis), a suite of software modules that implement the new ICRP models for estimation of intakes and doses. This was partly in response to new UK regulations, and partly due to the requirement for a unified approach in estimating intakes and doses from bioassay measurements within the UK. Over the past 5 years, the IMBA modules have been developed further, have gone through extensive quality assurance, and are now used for routine dose assessment by approved dosimetry services throughout the UK. More recently, interest in the IMBA methodology has been shown by the United States Department of Energy (USDOE), and in 2001 an ambitious project to develop a software package (IMBA Expert USDOE Edition) which would meet the requirements of all of the major USDOE sites began. Interest in IMBA Expert is now being expressed in many other countries. The aim of this paper is to outline the origin and evolution of the IMBA modules (the past); to describe the full capabilities of the current IMBA Expert system (the present) and to indicate possible future directions in terms of capabilities and availability (the future).

  8. Calibration facility for environment dosimetry instruments

    Energy Technology Data Exchange (ETDEWEB)

    Bercea, Sorin; Celarel, Aurelia; Cenusa, Constantin [Horia Hulubei National Institute for Physics and Nuclear Engineering, 30 Reactorului St, Magurele, Jud Ilfov, P.O.B. MG-6, RO-077125 (Romania)

    2013-12-16

    In the last ten years, the nuclear activities, as well as the major nuclear events (see Fukushima accident) had an increasing impact on the environment, merely by contamination with radioactive materials. The most conferment way to quickly identify the presence of some radioactive elements in the environment, is to measure the dose-equivalent rate H. In this situation, information concerning the values of H due only to the natural radiation background must exist. Usually, the values of H due to the natural radiation background, are very low (∼10{sup −9} - 10{sup −8} Sv/h). A correct measurement of H in this range involve a performing calibration of the measuring instruments in the measuring range corresponding to the natural radiation background lead to important problems due to the presence of the natural background itself the best way to overlap this difficulty is to set up the calibration stand in an area with very low natural radiation background. In Romania, we identified an area with such special conditions at 200 m dept, in a salt mine. This paper deals with the necessary requirements for such a calibration facility, as well as with the calibration stand itself. The paper includes also, a description of the calibration stand (and images) as well as the radiological and metrological parameters. This calibration facilities for environment dosimetry is one of the few laboratories in this field in Europe.

  9. Beta-particle dosimetry in radiation synovectomy

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, L.S. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Nuclear Engineering; Yanch, J.C. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Nuclear Engineering; Shortkroff, S. [Department of Orthopedic Surgery, Brigham and Women`s Hospital, Boston, MA (United States); Barnes, C.L. [Department of Orthopedic Surgery, Brigham and Women`s Hospital, Boston, MA (United States); Spitzer, A.I. [Department of Orthopedic Surgery, Brigham and Women`s Hospital, Boston, MA (United States); Sledge, C.B. [Department of Orthopedic Surgery, Brigham and Women`s Hospital, Boston, MA (United States)

    1995-09-01

    Beta-particle dosimetry of various radionuclides used in the treatment of rheumatoid arthritis was estimated using Monte Carlo radiation transport simulation coupled with experiments using reactor-produced radionuclides and radiachromic film dosimeters inserted into joint phantoms and the knees of cadavers. Results are presented as absorbed dose factors (cGy-cm{sup 2}/MBq-s) versus depth in a mathematical model of the rheumatoid joint which includes regions of bone, articular cartilage, joint capsule, and tissue (synovium) found in all synovial joints. The factors can be used to estimate absorbed dose and dose rate distributions in treated joints. In particular, guidance is provided for those interested in (a) a given radionuclide`s therapeutic range, (b) the amount of radioactivity to administer on a case-by-case basis, (c) the expected therapeutic dose to synovium, and (d) the radiation dose imparted to other, nontarget components in the joint, including bone and articular cartilage. (orig.). With 6 figs., 6 tabs.

  10. Dosimetry of radioiodine for embryo and fetus

    Energy Technology Data Exchange (ETDEWEB)

    Berkovski, V.; Eckerman, K.F.; Phipps, A.W.; Nosske, D

    2003-07-01

    This paper discusses the biokinetic and dosimetric models adopted in ICRP Publication 88 for the evaluation of fetal doses resulting from maternal intakes of radioiodine. The biokinetic model is used to simulate the behaviour of iodine in both the mother and the fetus. Such simulations provide the basis for the estimation of the dose to the embryo and determine the distribution of maternal iodine at the beginning of the fetal period. The model considers iodine to accumulate in the fetal thyroid from the 11th week. The dose to the fetus delivered following birth is evaluated with the biokinetic and dosimetric models described in ICRP Publication 67. Although a substantial fraction of the emitted energy of electrons and photons is less than 10 keV, conventionally assumed to be non-penetrating radiation, these emissions can escape the small fetal thyroid. Absorbed fractions for both self-dose and crossfire were evaluated for the requirements of radioiodine dosimetry in ICRP Publication 88. (author)

  11. Oxygen measurements to improve singlet oxygen dosimetry

    Science.gov (United States)

    Kim, Michele M.; Penjweini, Rozhin; Ong, Yi Hong; Finlay, Jarod C.; Zhu, Timothy C.

    2017-02-01

    Photodynamic therapy (PDT) involves interactions between the three main components of light fluence, photosensitizer concentration, and oxygenation. Currently, singlet oxygen explicit dosimetry (SOED) has focused on the first two of these components. The macroscopic model to calculate reacted singlet oxygen has previously involved a fixed initial ground state oxygen concentration. A phosphorescence-based oxygen probe was used to measure ground state oxygen concentration throughout treatments for mice bearing radioactively induced fibroscarcoma tumors. Photofrin-, BPD-, and HPPH-mediated PDT was performed on mice. Model-calculated oxygen and measured oxygen was compared to evaluate the macroscopic model as well as the photochemical parameters involved. Oxygen measurements at various depths were compared to calculated values. Furthermore, we explored the use of noninvasive diffuse correlation spectroscopy (DCS) to measure tumor blood flow changes in response to PDT to improve the model calculation of reacted singlet oxygen. Mice were monitored after treatment to see the effect of oxygenation on long-term recurrence-free survival as well as the efficacy of using reacted singlet oxygen as a predictive measure of outcome. Measurement of oxygenation during treatment helps to improve SOED as well as confirm the photochemical parameters involved in the macroscopic model. Use of DCS in predicting oxygenation changes was also investigated.

  12. Reactor dosimetry and RPV life management

    Energy Technology Data Exchange (ETDEWEB)

    Belousov, S.; Ilieva, K.; Mitev, M. [Inst. for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Tsarigradsko 72, 1784 Sofia (Bulgaria)

    2011-07-01

    Reactor dosimetry (RD) is a tool that provides data for neutron fluence accumulated over the reactor pressure vessel (RPV) during the reactor operation. This information, however, is not sufficient for RPV lifetime assessment. The life management of RPV is a multidisciplinary task. To assess whether the RPV steel properties at the current stage (for actual accumulated neutron fluence) of reactor operation are still 'safe enough,' the dependence of material properties on the fluence must be known; this is a task for material science (MS). Moreover, the mechanical loading over the RPV during normal operation and accidence have to be known, as well, for evaluation, if the RPV material integrity in this loading condition and existing cracks is provided. The crack loading path in terms of stress intensity factor is carried out by structural analyses (SA). Pressure and temperature distribution over RPV used in these analyses are obtained from a thermal hydraulic (TH) calculation. The conjunction of RD and other disciplines in RPV integrity assessment is analyzed in accordance with the FFP (fitness for purpose) approach. It could help to improve the efficiency in multi-disciplinary tasks solutions. (authors)

  13. Calibration facility for environment dosimetry instruments

    Science.gov (United States)

    Bercea, Sorin; Celarel, Aurelia; Cenusa, Constantin

    2013-12-01

    In the last ten years, the nuclear activities, as well as the major nuclear events (see Fukushima accident) had an increasing impact on the environment, merely by contamination with radioactive materials. The most conferment way to quickly identify the presence of some radioactive elements in the environment, is to measure the dose-equivalent rate H. In this situation, information concerning the values of H due only to the natural radiation background must exist. Usually, the values of H due to the natural radiation background, are very low (˜10-9 - 10-8 Sv/h). A correct measurement of H in this range involve a performing calibration of the measuring instruments in the measuring range corresponding to the natural radiation background lead to important problems due to the presence of the natural background itself the best way to overlap this difficulty is to set up the calibration stand in an area with very low natural radiation background. In Romania, we identified an area with such special conditions at 200 m dept, in a salt mine. This paper deals with the necessary requirements for such a calibration facility, as well as with the calibration stand itself. The paper includes also, a description of the calibration stand (and images) as well as the radiological and metrological parameters. This calibration facilities for environment dosimetry is one of the few laboratories in this field in Europe.

  14. The different behavior of rutile and anatase nanoparticles in forming oxy radicals upon illumination with visible light: an EPR study.

    Science.gov (United States)

    Lipovsky, Anat; Levitski, Luba; Tzitrinovich, Zeev; Gedanken, Aharon; Lubart, Rachel

    2012-01-01

    Photoexcited TiO(2) has been found to generate reactive oxygen species, yet the precise mechanism and chemical nature of the generated oxy species especially regarding the different crystal phases remain to be elucidated. Visible light-induced reactions of a suspension of titanium dioxide (TiO(2)) in water were investigated using electron paramagnetic resonance (EPR) coupled with the spin-trapping technique. Increased levels of both hydroxyl (˙OH) and superoxide anion (˙O(2)(-)) radicals were detected in TiO(2) rutile and anatase nanoparticles (50 nm). The intensity of signals assigned to the ˙OH and ˙O(2)(-) radicals was larger for the anatase phase than that originating from rutile. Moreover, illumination with visible (nonUV) light enhanced ˙O(2)(-) formation in the rutile phase. Singlet oxygen was not detected in water suspension of TiO(2) neither in rutile nor in anatase nanoparticles, but irradiation of the rutile phase with visible light revealed a signal, which could be attributed to singlet oxygen formation. The blue part of visible spectrum (400-500 nm) was found to be responsible for the light-induced ROS in TiO(2) nanoparticles. The characterization of the mechanism of visible light-induced oxy radicals formation by TiO(2) nanoparticles could contribute to its use as a sterilization agent.

  15. Implementation of IMRT and VMAT using Delta4 phantom and portal dosimetry as dosimetry verification tools

    Energy Technology Data Exchange (ETDEWEB)

    Daci, Lulzime, E-mail: lulzime.daci@nodlandssykehuset.no [Nordland Hospital Trust, Bodø (Norway); Malkaj, Partizan, E-mail: malkaj-p@hotmail.com [Faculty of Mathematics Engineering and Physics Engineering, Polytechnic University of Tirana (Albania)

    2016-03-25

    In this study we analyzed and compared the dose distribution of different IMRT and VMAT plans with the intent to provide pre-treatment quality assurance using two different tools. Materials/Methods: We have used the electronic portal imaging device EPID after calibration to dose and correction for the background offset signal and also the Delta4 phantom after en evaluation of angular sensitivity. The Delta4 phantom has a two-dimensional array with ionization chambers. We analyzed three plans for each anatomical site calculated by Eclipse treatment planning system. The measurements were analyzed using γ-evaluation method with passing criteria 3% absolute dose and 3 mm distance to agreement (DTA). For all the plans the range of score has been from 97% to 99% for gantry fixed at 0° while for rotational planes there was a slightly decreased pass rates and above 95%. Point measurement with a ionization chamber were done in additional to see the accuracy of portal dosimetry and to evaluate the Delta4 device to various dose rates. Conclusions: Both Delt4 and Portal dosimetry shows good results between the measured and calculated doses. While Delta4 is more accurate in measurements EPID is more time efficient. We have decided to use both methods in the first steps of IMRT and VMAT implementation and later on to decide which of the tools to use depending on the complexity of plans, how much accurate we want to be and the time we have on the machine.

  16. Implementation of IMRT and VMAT using Delta4 phantom and portal dosimetry as dosimetry verification tools

    Science.gov (United States)

    Daci, Lulzime; Malkaj, Partizan

    2016-03-01

    In this study we analyzed and compared the dose distribution of different IMRT and VMAT plans with the intent to provide pre-treatment quality assurance using two different tools. Materials/Methods: We have used the electronic portal imaging device EPID after calibration to dose and correction for the background offset signal and also the Delta4 phantom after en evaluation of angular sensitivity. The Delta4 phantom has a two-dimensional array with ionization chambers. We analyzed three plans for each anatomical site calculated by Eclipse treatment planning system. The measurements were analyzed using γ-evaluation method with passing criteria 3% absolute dose and 3 mm distance to agreement (DTA). For all the plans the range of score has been from 97% to 99% for gantry fixed at 0° while for rotational planes there was a slightly decreased pass rates and above 95%. Point measurement with a ionization chamber were done in additional to see the accuracy of portal dosimetry and to evaluate the Delta4 device to various dose rates. Conclusions: Both Delt4 and Portal dosimetry shows good results between the measured and calculated doses. While Delta4 is more accurate in measurements EPID is more time efficient. We have decided to use both methods in the first steps of IMRT and VMAT implementation and later on to decide which of the tools to use depending on the complexity of plans, how much accurate we want to be and the time we have on the machine.

  17. EPR and optical absorption studies of Cr3+ ions in d-gluconic acid monohydrate.

    Science.gov (United States)

    Kripal, Ram; Singh, Pragya; Govind, Har

    2009-10-01

    EPR studies are carried out on Cr(3+) ions doped in d-gluconic acid monohydrate (C(6)H(12)O(7)*H(2)O) single crystals at 77 K. From the observed EPR spectra, the spin Hamiltonian parameters g, |D| and |E| are measured to be 1.9919, 349 (x 10(-4)) cm(-1) and 113 (x 10(-4)) cm(-1), respectively. The optical absorption of the crystal is also studied at room temperature. From the observed band positions, the cubic crystal field splitting parameter Dq (2052 cm(-1)) and the Racah interelectronic repulsion parameter B (653 cm(-1)) are evaluated. From the correlation of EPR and optical data the nature of bonding of Cr(3+) ion with its ligands is discussed.

  18. On Room-Temperature Inversion of EPR Signals of P1 Centre in Synthetic Diamond

    Institute of Scientific and Technical Information of China (English)

    G. G. Fedoruk; O. N. Poklonskaya

    2009-01-01

    Room-temperature inversion of EPR absorption signals of P1 centre in synthetic diamond is studied by the tran-sient nutation technique. Use of the bichromatic field, consisting of a transverse microwave field and longitudinal radio frequency field, allows to investigate the dynamics of P1 centres in the same field configuration as in cw EPR spectrometers. It is shown that the annealing decreases the P1 centre concentration and, respectively, increases the spin-spin relaxation time. As a result, the periodic inversion (nutation) of the P1 centre absorption signal is observed longer. It is assumed that the P1 centre signal inversion, which was previously observed by cw EPR, might be caused by the Bloch-Siegert effect in the biehromatic field.

  19. In vivo EPR: an effective new tool for studying pathophysiology, physiology and pharmacology

    Energy Technology Data Exchange (ETDEWEB)

    Maeder, K.; Swartz, H.M. [Dartmouth Univ., Hanover, NH (United States). Dept. of Radiology; Gallez, B. [Louvain Univ., Brussels (Belgium). Dept. of Medicinal Chemistry

    1996-11-01

    The development of spectrometers working at lower frequencies with improved resonators now permits the routine use of non-invasive EPR spectroscopy in vivo. The capabilities of EPR spectra to reflect environmental conditions, combined with the use of paramagnetic materials as selective non-toxic labels, has led to increasingly widespread and productive applications of the technique to complex problems involving physiology, pharmacology and pathophysiology. Some of the especially promising applications in which EPR techniques uniquely appear to provide valuable information are illustrated, including the measurement of oxygen and oxygen gradients, monitoring of the metabolism of xenobiotics, monitoring pharmacokinetics of drugs, measurement of perfusion, measurement of pH, recognition and labeling of receptors, and characterization of drug releasing systems. (author).

  20. EPR, UV-Visible, and Near-Infrared Spectroscopic Characterization of Dolomite

    Directory of Open Access Journals (Sweden)

    S. Lakshmi Reddy

    2008-01-01

    Full Text Available Dolomite mineral samples having white and light green colors of Indian origin have been characterized by EPR, optical, and NIR spectroscopy. The optical spectrum exhibits a number of electronic bands due to presence of Fe(III ions in the mineral. From EPR studies, the parameters of g for Fe(III and g,A, and D for Mn(II are evaluated and the data confirm that the ions are in distorted octahedron. Optical absorption studies reveal that Fe(III is in distorted octahedron. The bands in NIR spectra are due to the overtones and combinations of water molecules. Thus EPR and optical absorption spectral studies have proven useful for the study of the solid state chemistry of dolomite.