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Sample records for formate epr dosimeters

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

    International Nuclear Information System (INIS)

    Yordanov, N.D.; Gancheva, V.

    1999-01-01

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

  2. New Generation of self-calibrated SS/EPR dosimeters: Alanine/EPR dosimeters

    International Nuclear Information System (INIS)

    Yordanov, N.D.; Gancheva, V.

    1999-01-01

    A new type of solid state/EPR dosimeters is described. Principally, it contains radiation sensitive diamagnetic material, some quantity of EPR active, but radiation insensitive, substance (for example Mn 2+ /MgO) and a binding material. In the present case alanine is used as a radiation sensitive substance. With this dosimeter, the EPR spectra of alanine and Mn 2+ are simultaneously recorded and the calibration graph represents the ratio of alanine versus Mn 2+ EPR signal intensity as a function of absorbed dose. In this way the reproducibility of the results is expected to be improved significantly including their intercomparison among different laboratories. Homogeneity of the prepared dosimeters and their behaviour (fading of EPR signals with time, influence of different meteorological conditions) show satisfactory reproducibility and stability with time. Because two different EPR active samples are recorded simultaneously, the influence of some instrument setting parameters (microwave power, modulation amplitude and modulation frequency) on the ratio I alanine /I Mn is also investigated. (author)

  3. The investigation of lithium formate hydrate, sodium dithionate and N-methyl taurine as clinical EPR dosimeters

    International Nuclear Information System (INIS)

    Lelie, S.; Hole, E.O.; Duchateau, M.; Schroeyers, W.; Schreurs, S.; Verellen, D.

    2013-01-01

    Introduction: EPR-dosimetry using L-α-alanine is an established method for measuring high doses of ionizing radiation. However, since a minimum dose of approximately 4 Gy is required to achieve sufficient low uncertainties (1–2%) for clinical application, alternative dosimeter materials are being inquired. Lithium formate (LiFo) monohydrate has been studied by several groups and has revealed several promising properties in the low dose region (<4 Gy). The fading properties, however, are somewhat unpredictable, and depend on properties not yet fully uncovered. This paper reports the results from a study of lithium formate hydrate and N-methyl taurine as potential low dose EPR dosimeters. Methods and materials: Pellet shaped dosimeters of lithium formate monohydrate, lithium formate hydrate, sodium dithionate and N-methyl taurine were produced using a manual Weber press, L-α-alanine was obtained from Harwell dosimeters and irradiated using 60 kV and 6 MV X-ray beams, and Co-60 gamma-rays to a dose of 30 Gy and dose ranges of 0.5–100 Gy and 2–20 Gy respectively. The dosimeters were measured using an Electron Paramagnetic Resonance (EPR)-spectrometer. The detector responses for 6 MV and Co-60 radiation beams, the fading behaviors and signal shape in time were investigated. Results: Lithium formate monohydrate and lithium formate hydrate are apparently associated with near identical EPR-spectra (mainly one broad line), and the same spectrum arises for all radiation energies investigated. The shape of the EPR resonance remains constant with time, but the intensities decreases, and the fading is more prominent for the monohydrate than for the hydrate. The EPR resonance associated with N-methyl taurine is more complex than the resonance associated with LiFo and it changes with time, implying radical transitions and growth. Conclusions: The study showed that lithium formate hydrate is a strong candidate for EPR dosimetry with slightly better fading characteristics

  4. Characterization of lithium formate EPR dosimeters for high dose applications – comparison with alanine

    DEFF Research Database (Denmark)

    Waldeland, Einar; Helt-Hansen, Jakob; Malinen, Eirik

    2011-01-01

    Lithium formate and l-α-alanine (alanine) EPR dosimeters were irradiated to doses from 100 Gy to 100 kGy. The irradiations were mainly performed at a Gammacell irradiator with dose rate of approximately 5.5 kGy h−1. Both the peak-to-peak amplitude of the first derivative EPR spectrum and the area...... irradiated to 1 kGy at temperatures from 11ºC to 40ºC were analyzed. By fitting an ‘exponential rise to maximum'-function to the dependence of the area under the EPR absorption spectrum on the dose, saturation doses of 53 kGy and 87 kGy for lithium formate and alanine, respectively, were found. Lower...... estimates were found when analyzing the dose dependence of the peak-to-peak amplitude. Furthermore, the peak-to-peak width was found to increase for doses above 10 kGy. No dose rate dependence for any of the studied materials was observed and the temperature coefficients at 25ºC (i.e. change in dosimeter...

  5. Water-resistant alanine-EPR dosimeter alanpol

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  6. Comparative study of some new EPR dosimeters

    International Nuclear Information System (INIS)

    Alzimami, K.S.; Maghraby, Ahmed M.; Bradley, D.A.

    2014-01-01

    Investigations have been made of four new radiation dosimetry EPR candidates from the same family of materials: sulfamic acid, sulfanillic acid, homotaurine, and taurine. Mass energy attenuation coefficients, mass stopping power values and the time dependence of the radiation induced radicals are compared. Also investigated are the microwave saturation behavior and the effect of applied modulation amplitude on both peak-to-peak line width (W PP ) and peak-to-peak signal height (H PP ). The dosimeters are characterized by simple spectra and stable radiation-induced radicals over reasonable durations, especially in taurine dosimeters. Sulfamic acid dosimeters possessed the highest sensitivity followed by taurine and homotaurine and sulfanillic. - Highlights: ► Several EPR dosimeters were suggested based on SO 3 − radical. ► Taurine, homotaurine, sulfanilic, and sulfamic acid all possess simple EPR spectra. ► Dosimeters were compared to each other in terms of the dosimetric point of view. ► Energy dependence curves of the selected dosimeters were compared to eachother

  7. EPR of gamma-irradiated polycrystalline alanine-in-glass dosimeter

    International Nuclear Information System (INIS)

    Al-Karmi, Anan M.; Morsy, M.A.

    2008-01-01

    This study attempts to overcome some of the reported discrepancies in alanine-EPR reproducibility that may be related to alanine dosimeter preparation and/or EPR spectrometer settings. The dosimeters were prepared by packing pure polycrystalline L-α-alanine directly as supplied by the manufacturer in glass tubes. This dosimeter production scheme avoids any possible contribution to the EPR signal from a binding material. The dosimeters were irradiated with gamma ray to low-dose ranges typical for medical therapy (0-20 Gy). Special attention has been paid to the study of minimum detectable dose, measurement repeatability and reproducibility, and post-irradiation stability. The dosimeter exhibited a linear dose response in the dose range from 0.1 to 20 Gy. These positive properties favor the polycrystalline alanine-in-glass tube as a radiation dosimeter

  8. Effect of the shape and size of dosimeters on the response of solid state/EPR dosimetry

    International Nuclear Information System (INIS)

    Yordanov, Nicola D.; Fabisiak, Slawomir; Lagunov, Oleg

    2006-01-01

    The influence of the shape and size of dosimeters used in solid state-EPR (SS/EPR) dosimetry on their response is reported. It is shown that for commonly used cylindrical (rod) shaped dosimeters of equal height, prepared of low (ε=<3) dielectric constant materials, linearity between their volume and the EPR response is observed when their diameter varies between 3 and 5mm. Further increase of the dosimeter's diameter is not recommended since the increased penetration of the dosimeter material into the electric component of the microwave field in the EPR cavity increases the dielectric losses and decreases the EPR response. In an attempt to improve the sensitivity of the SS/EPR dosimetry we have prepared and tested new, flat-shaped, dosimeters of low (ε∼2) dielectric constant materials which were found to exhibit: (i) linear EPR response within 1-5mm thickness; (ii) higher sensitivity than cylindrical dosimeters at equal sample volume; (iii) increased by ca. 270% EPR sensitivity at 5mm thickness compared to the cylindrical dosimeters with the same diameter (ca. 1.7 times increased sample volume). Using flat shape dosimeters of suitable size provides 2.7 times higher EPR sensitivity of single estimation

  9. Electron paramagnetic resonance radiation dosimetry: possible inorganic alternatives to the EPR/alanine dosimeter

    International Nuclear Information System (INIS)

    Keizer, P.N.; Morton, J.R.; Preston, K.F.

    1991-01-01

    The intensity of the EPR spectrum of γ-irradiated L-α-alanine has been accepted by the International Atomic Energy Agency as a secondary standard for high-dose (10-100 000 Gy) dosimetry. The alanine dosimeter is not without its disadvantages, however, and in this article alternative EPR dosimeters are explored. These include SO 3 - in irradiated K 2 CH 2 (SO 3 ) 2 and CO 2 - in irradiated sodium formate (NaHCO 2 ), both of which have some advantages over CH 3 CHCO 2 - in L-α-alanine. Using as a readout parameter the peak-to-peak excursion of the strongest line, these systems have a four-fold sensitivity advantage over alanine. The radicals SO 3 - and CO 2 - are, moreover, found in a wide variety of matrices, and it may be possible to find one in which they are even stronger. The need to discover a dosimeter material sensitive enough to function in the 'clinical' dose range (below 10 Gy) is emphasized. (author)

  10. Properties of the ammonium tartrate/EPR dosimeter

    International Nuclear Information System (INIS)

    Yordanov, N.D.; Gancheva, V.

    2004-01-01

    The EPR response of γ-irradiated ammonium tartrate on the absorbed dose of γ-rays up to 22 kGy as well as the changes in the shape of the EPR spectrum upon applied modulation amplitude and microwave power are reported. Also the possibility to use ammonium tartrate together with Mn 2+ magnetically diluted in MgO as an internal reference material is evaluated. The influence of the microwave power and the modulation amplitude on their dose response is investigated. The results show that the radiation-induced EPR spectrum of ammonium tartrate, obtained at a low microwave power is complex consisting several patterns and is more easily saturated than the Mn 2+ EPR spectrum. In this case the following settings of the EPR parameters are recommended: H mod ≤0.05 mT and 10≤P MW ≤13 mW. Using these parameters the dosimeters can be considered for use in intercomparisons

  11. Some physico-technical aspects of the new generation of self-calibrated alanine/EPR dosimeter and results from the international intercomparison trial

    International Nuclear Information System (INIS)

    Yordanov, N.D.; Gancheva, V.

    2000-01-01

    Some physico-technical parameters of the self-calibrated alanine/EPR dosimeters are described. Principally, this new type of solid state/EPR dosimeter contains radiation sensitive diamagnetic material (in the present case, alanine), some quantity of EPR active, but radiation insensitive, substance (for example, Mn 2+ /MgO) playing roles of an internal standard and a binding material. Thus with this dosimeter the EPR spectra of alanine and the internal standard Mn 2+ are recorded simultaneously and the dose response is represented as a ratio of EPR signal intensities of alanine versus Mn 2+ as a function of absorbed dose. As a result, the data of the present study have shown that there is practically no interference of the dosimeter EPR response (expressed as the ratio I alanine /I Mn ) from the way of preparation (homogeneity), behavior after irradiation (fading of EPR signals with time, influence of different meteorological conditions) as well as specific spectrometer setting conditions. These dosimeters show satisfactory reproducibility of preparation and reading as well as stability on keeping. Thus, fulfilling the described physico-technical data of this type of dosimeters, the reproducibility of the readings is significantly improved particularly when intercomparison among different laboratories is performed. This conclusion is confirmed by independent studies of the described self-calibrated alanine/EPR dosimeters in several laboratories in Europe. Results of which are also reported. (author)

  12. Development of a new dosimeter of EPR based on lactose

    International Nuclear Information System (INIS)

    Cruz C, L.; Torijano C, E.; Azorin N, J.; Aguirre G, F.; Cruz Z, E.

    2014-08-01

    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 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 -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)

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

    International Nuclear Information System (INIS)

    Grazyna Przybytniak; Zagorski, Z.P.

    1996-01-01

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

  14. 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)

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

    International Nuclear Information System (INIS)

    Vega R, J. L.; Nicolucci, P.; Baffa, O.; Chen, F.; Apaza V, D. G.

    2014-08-01

    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 2 and 1 x 1 cm 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)

  16. EPR Dosimetry for ageing effect in NPP

    International Nuclear Information System (INIS)

    Choi, Hoon; Lim, Young Ki; Kim, Jong Seog; Jung, Sun Chul

    2005-01-01

    As one of the retrospective dosimetry method, EPR spectroscopy has been studied by many research up to theses days. As a dosimeter for EPR spectroscopy, Alanine is already a well known dosimeter in the field of radiation therapy and dose assessment in radiological accident by its characteristics as good linearity in a wide range of energy level and extremely low signal fading on time. Through technical document of IAEA, the EPR dosimetry method using alanine sample was published in 2000 after research by coordinated project on management of ageing of in-containment I and C cables. Although alanine sample is regarded as a good EPR dosimeter like above ageing assessment field, actually the assessment of radiation should be done at least for two fuel cycles, because of its relatively low irradiation environment in almost all spots in power plant. So, for getting more accurate detection value of radiation, another material is tested for being put in simultaneously inside the power plant with alanine. The test result for lithium formate monohydrate (HCO 2 LiH 2 0) was presented below for checking its possibility for being applied as EPR dosimeter for this project

  17. Lithium formate EPR dosimetry for verifications of planned dose distributions prior to intensity-modulated radiation therapy

    Science.gov (United States)

    Gustafsson, H.; Lund, E.; Olsson, S.

    2008-09-01

    The objective of the present investigation was to evaluate lithium formate electron paramagnetic resonance (EPR) dosimetry for measurement of dose distributions in phantoms prior to intensity-modulated radiation therapy (IMRT). Lithium formate monohydrate tablets were carefully prepared, and blind tests were performed in clinically relevant situations in order to determine the precision and accuracy of the method. Further experiments confirmed that within the accuracy of the current method, the dosimeter response was independent of beam energies and dose rates used for IMRT treatments. The method was applied to IMRT treatment plans, and the dose determinations were compared to ionization chamber measurements. The experiments showed that absorbed doses above 3 Gy could be measured with an uncertainty of less than 2.5% of the dose (coverage factor k = 1.96). Measurement time was about 15 min using a well-calibrated dosimeter batch. The conclusion drawn from the investigation was that lithium formate EPR dosimetry is a promising new tool for absorbed dose measurements in external beam radiation therapy, especially for doses above 3 Gy.

  18. Lithium formate EPR dosimetry for verifications of planned dose distributions prior to intensity-modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, H; Lund, E [Department of Medical and Health Sciences, Radiation Physics, Faculty of Health Sciences, Linkoeping University, S-581 85 Linkoeping (Sweden); Olsson, S [Division of Radiation Physics, Linkoeping University Hospital, S-581 85 Linkoeping (Sweden)], E-mail: hakgu@imv.liu.se

    2008-09-07

    The objective of the present investigation was to evaluate lithium formate electron paramagnetic resonance (EPR) dosimetry for measurement of dose distributions in phantoms prior to intensity-modulated radiation therapy (IMRT). Lithium formate monohydrate tablets were carefully prepared, and blind tests were performed in clinically relevant situations in order to determine the precision and accuracy of the method. Further experiments confirmed that within the accuracy of the current method, the dosimeter response was independent of beam energies and dose rates used for IMRT treatments. The method was applied to IMRT treatment plans, and the dose determinations were compared to ionization chamber measurements. The experiments showed that absorbed doses above 3 Gy could be measured with an uncertainty of less than 2.5% of the dose (coverage factor k = 1.96). Measurement time was about 15 min using a well-calibrated dosimeter batch. The conclusion drawn from the investigation was that lithium formate EPR dosimetry is a promising new tool for absorbed dose measurements in external beam radiation therapy, especially for doses above 3 Gy.

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  20. 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)

  1. EPR Study of Free Radicals in Cotton Fiber for Its Potential Use as a Fortuitous Dosimeter in Radiological Accidents

    International Nuclear Information System (INIS)

    Sudprasert, W.; Insuan, P.; Khamkhrongmee, S.

    2014-01-01

    Electron paramagnetic resonance (EPR) spectroscopy was applied to characterize radiation- induced free radicals in cotton fiber in order to determine the possibility for using cotton as a fortuitous dosimeter in accidental exposures to radiation. Cotton fabrics were irradiated at 0.1, 0.5, 1, 2, 10, 50 and 500 Gy using a 60Co gamma source. The irradiated samples were then stored in the dark under controlled environmental conditions for 1, 15, 35 and 60 days. The EPR spectra were observed in samples using a Bruker EMX X-band spectrometer equipped with a TE102 rectangular cavity. The EPR signal intensities of irradiated samples were determined from peak-to-peak amplitudes of EPR spectra and compared to unirradiated samples. The following optimum parameters were used: modulation frequency,100 kHz; microwave frequency, 9.84 GHz; modulation amplitude, 1.8 mT; microwave power,1.0 mW; time constant, 665 ms; conversion time, 41 ms; and sweep time, 41.98 s. The EPR spectra of unirradiated samples show a singlet line with g = 2.006 due to stable organic radicals pre-existing in the cotton fibers, whereas those of irradiated samples show the same pattern with different signal intensities according to the doses. Irradiation increased the signal intensity in a dose dependent manner. The signal intensity exhibited an exponential decay with storage time from 1 to 60 days. Obviously, the degree of fading of EPR intensity did not depend on the absorbed dose from 0.1-50 Gy. The maximum fading was about 60% at 60 days storage of irradiated samples at all doses. However the post-irradiation signal appeared to be detectable up to 60 days after irradiation. The results indicate the potential of using cotton as a fortuitous dosimeter in radiological accidents.

  2. EPR dosimetric properties of 2-methylalanine pellet for radiation processing application

    International Nuclear Information System (INIS)

    Soliman, Y.S.; Ali, Laila I.; Moustafa, H.; Tadros, Soad M.

    2014-01-01

    The dosimetric characteristics of γ-radiation induced free radicals in 2-methylalanine (2MA) pellet dosimeter are investigated using electron paramagnetic resonance (EPR) in the high-dose range of 1–100 kGy. The EPR spectrum of γ-irradiated 2MA exhibits an isotropic EPR signal with seven lines. The dosimeter response is humidity independent in the range of 33–76% relative humidity. The manufactured dosimeter is typically adipose tissue equivalent in the energy level of 0.1–15 MeV. The overall uncertainty (2σ) of the dosimeter is less than 6.9%. - Highlights: • Preparation of 2-methyl alanine pellets for high-dose dosimetry (1–100 kGy). • The dosimeter response is humidity independent in 33–76% relative humidity range during irradiation. • The temperature coefficient equals 0.96%/°C in the range of 21–60 °C. • Overall uncertainty of the dosimeter not exceeds 6.9% at 2σ

  3. EPR of gamma irradiated solid sucrose and UV spectra of its solution. An attempt for calibration of solid state/EPR dosimetry

    International Nuclear Information System (INIS)

    Yordanov, N.D.; Karakirova, Y.

    2007-01-01

    A simple new approach for independent calibration of solid state/EPR (SS/EPR) dosimetry system is reported. It is based on the fact that: (i) gamma-irradiation of solid sucrose (sugar) induces stable EPR detectable free radicals accompanied by UV detectable brown colour stable in the solid state and in solution; (ii) both the EPR intensity of gamma-irradiated solid sucrose and its solution UV absorbance linearly depend on the absorbed dose high energy radiation and may be independently used for dosimetric purpose; (iii) UV spectrometers are calibrated. The correlation between EPR response and absorbed dose radiation of solid sucrose and UV absorption of its solutions is used in the present communication for calibration purpose. The procedure of sucrose extraction from sucrose-paraffin dosimeters is described. The calibration procedure may be applied to any other (alanine, self-calibrated, etc.) SS/EPR dosimeters, simultaneously irradiated with sucrose

  4. Calcium carbonate as a possible dosimeter for high irradiation doses

    International Nuclear Information System (INIS)

    Negron M, A.; Ramos B, S.; Camargo R, C.; Uribe, R. M.; Gomez V, V.; Kobayashi, K.

    2014-08-01

    The aim of this work is to analyze the interactions of 5 MeV electron beam radiation and a 290 MeV/u Carbon beam with calcium carbonate (powder) at 298 K and at different irradiation doses, for the potential use of calcium carbonate as a high-dose dosimeter. The irradiation doses with the electron beam were from 0.015 to 9 MGy, and with Carbon beam from 1.5 kGy to 8 kGy. High-energy radiation induces the formation of free radicals in solid calcium carbonate that can be detected and measured by electron paramagnetic resonance (EPR). An increase of the EPR response for some of the free radicals produced in the sample was observed as a function of the irradiation dose. The response of one of the radicals decreased with the dose. These measurements are reproducible; the preparation of the sample is simple and inexpensive; and the signal is stable for several months. The response curves show that the dosimeter tends to saturate at 10 MGy. Based on these properties, we propose this chemical compound as a high-dose dosimeter, mainly for electron irradiation. (author)

  5. Calcium carbonate as a possible dosimeter for high irradiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Negron M, A.; Ramos B, S.; Camargo R, C. [UNAM, Instituto de Ciencias Nucleares, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Uribe, R. M. [Kent State University, College of Technology, Kent OH (United States); Gomez V, V. [UNAM, Instituto de Quimica, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Kobayashi, K., E-mail: negron@nucleares.unam.mx [Yokohama National University (Japan)

    2014-08-15

    The aim of this work is to analyze the interactions of 5 MeV electron beam radiation and a 290 MeV/u Carbon beam with calcium carbonate (powder) at 298 K and at different irradiation doses, for the potential use of calcium carbonate as a high-dose dosimeter. The irradiation doses with the electron beam were from 0.015 to 9 MGy, and with Carbon beam from 1.5 kGy to 8 kGy. High-energy radiation induces the formation of free radicals in solid calcium carbonate that can be detected and measured by electron paramagnetic resonance (EPR). An increase of the EPR response for some of the free radicals produced in the sample was observed as a function of the irradiation dose. The response of one of the radicals decreased with the dose. These measurements are reproducible; the preparation of the sample is simple and inexpensive; and the signal is stable for several months. The response curves show that the dosimeter tends to saturate at 10 MGy. Based on these properties, we propose this chemical compound as a high-dose dosimeter, mainly for electron irradiation. (author)

  6. Comparison of EPR response of alanine and Gd₂O₃-alanine dosimeters exposed to TRIGA Mainz reactor.

    Science.gov (United States)

    Marrale, M; Schmitz, T; Gallo, S; Hampel, G; Longo, A; Panzeca, S; Tranchina, L

    2015-12-01

    In this work we report some preliminary results regarding the analysis of electron paramagnetic resonance (EPR) response of alanine pellets and alanine pellets added with gadolinium used for dosimetry at the TRIGA research reactor in Mainz, Germany. Two set-ups were evaluated: irradiation inside PMMA phantom and irradiation inside boric acid phantom. We observed that the presence of Gd2O3 inside alanine pellets increases the EPR signal by a factor of 3.45 and 1.24 in case of PMMA and boric acid phantoms, respectively. We can conclude that in the case of neutron beam with a predominant thermal neutron component the addition of gadolinium oxide can significantly improve neutron sensitivity of alanine pellets. Monte Carlo (MC) simulations of both response of alanine and Gd-added alanine pellets with FLUKA code were performed and a good agreement was achieved for pure alanine dosimeters. For Gd2O3-alanine deviations between MC simulations and experimental data were observed and discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Alanine EPR dosimeter response in proton therapy beams

    International Nuclear Information System (INIS)

    Gall, K.; Serago, C.; Desrosiers, M.; Bensen, D.

    1997-01-01

    We report a series of measurements directed to assess the suitability of alanine as a mailable dosimeter for dosimetry quality assurance of proton radiation therapy beams. These measurements include dose-response of alanine at 140 MeV, and comparison of response vs energy with a parallel plate ionization chamber. All irradiations were made at the Harvard Cyclotron Laboratory, and the dosimeters were read at NIST. The results encourage us that alanine could be expected to serve as a mailable dosimeter with systematic error due to differential energy response no greater than 3% when doses of 25 Gy are used. (Author)

  8. Sugar dosimeters. Part 1. State of the art

    International Nuclear Information System (INIS)

    Peimel-Stuglik, Z.

    2008-01-01

    A review of the literature dealing with the possibility of using sugars, in particular sucrose, as dosimetric material is presented. All methods involved were divided according to analytical techniques used in dosimetric signal measurements (polarimetry, spectrophotometry and electron paramagnetic resonance - EPR). Double-signal sugar dosimeters (EPR + spectrophotometry) are also described. (author) [pl

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

    International Nuclear Information System (INIS)

    Hayes, Robert B.; Haskell, E.H.; Wieser, Albrecht; Romanyukha, Alexander A.; Hardy, Byron L.; Barrus, Jeffrey 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

  10. 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.

  11. Alanine-EPR as a transfer standard dosimetry system for low energy X radiation

    International Nuclear Information System (INIS)

    Khoury, H.J.; Silva, E.J. da; Mehta, K.; Barros, V.S. de; Asfora, V.K.; Guzzo, P.L.; Parker, A.G.

    2015-01-01

    The purpose of this paper is to evaluate the use of alanine-EPR as a transfer standard dosimetry system for low energy X radiation, such as that in RS-2400, which operates in the range from 25 to 150 kV and 2 to 45 mA. Two types of alanine dosimeters were investigated. One is a commercial alanine pellets from Aérial-Centre de Ressources Technologiques, France and one was prepared in our laboratory (LMRI-DEN/UFPE). The EPR spectra of the irradiated dosimeters were recorded in the Nuclear Energy Department of UFPE, using a Bruker EMX10 EPR spectrometer operating in the X-band. The alanine-EPR dosimetry system was calibrated in the range of 20–220 Gy in this X-ray field, against an ionization chamber calibrated at the relevant X-ray energy with traceability to PTB. The results showed that both alanine dosimeters presented a linear dose response the same sensitivity, when the EPR signal was normalized to alanine mass. The total uncertainty in the measured dose was estimated to be about 3%. The results indicate that it is possible to use the alanine-EPR dosimetry system for validation of a low-energy X ray irradiator, such as RS-2400.

  12. Application of Glycine-TTC dosimeter in gamma radiation processing facility

    International Nuclear Information System (INIS)

    Shinde, S.H.; Mondal, S.; Kulkarni, M.S.

    2018-01-01

    Glycine-TTC dosimeter was found to have a useful dose range of 5 to 30 kGy using spectro-photometric read-out method. Potential use of this dosimeter was demonstrated by measuring dose-rate in gamma chamber GC 900. The aim of the present study was to verify the performance of this dosimeter in actual industrial processing conditions encountered in radiation processing facility such as Gamma Radiation Processing Plant for Spices (GRPPS), BRIT, Vashi. Accordingly, glycine-TTC dosimeters were irradiated along with routine dosimeter viz. ceric-cerous of GRPPS and reference standard dosimeter viz. alanine EPR

  13. Flexible, wireless, inductively coupled surface coil resonator for EPR tooth dosimetry

    International Nuclear Information System (INIS)

    Schreiber, Wilson; Petryakov, Sergey V.; Kmiec, Maciej M.; Feldman, Matthew A.; Wood, Victoria A.; Boyle, Holly K.; Flood, Ann Barry; Williams, Benjamin B.; Swartz, Harold M.; Meaney, Paul M.

    2016-01-01

    Managing radiation injuries following a catastrophic event where large numbers of people may have been exposed to life-threatening doses of ionizing radiation relies on the availability of biodosimetry to assess whether individuals need to be triaged for care. Electron Paramagnetic Resonance (EPR) tooth dosimetry is a viable method to accurately estimate the amount of ionizing radiation to which an individual has been exposed. In the intended measurement conditions and scenario, it is essential that the measurement process be fast, straightforward and provides meaningful and accurate dose estimations for individuals in the expected measurement conditions. The sensing component of a conventional L-band EPR spectrometer used for tooth dosimetry typically consists of a surface coil resonator that is rigidly, physically attached to the coupler. This design can result in cumbersome operation, limitations in teeth geometries that may be measured and hinder the overall utility of the dosimeter. A novel surface coil resonator has been developed for the currently existing L-band (1.15 GHz) EPR tooth dosimeter for the intended use as a point of care device by minimally trained operators. This resonator development provides further utility to the dosimeter, and increases the usability of the dosimeter by non-expert operators in the intended use scenario. (authors)

  14. Alanine/epr pellet dosimeter using poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) copolymer as a binder for radiation dosimetry

    International Nuclear Information System (INIS)

    Beshir, W.B.; Ezz El-Din, H.M.; Abdel-fatth, A.A.; Ebraheem, S.

    2005-01-01

    A new alanine pellet dosimeter was developed for gamma and electron beam radiation dosimetry. Alanine powder was mixed with a new binding material, poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) copolymer. Pellets were prepared by pressing fine powder alanine with 60% copolymer binder by using hydraulic press and a specially designed pressing die. The radiation-formed stable free radicals were analysed by using electron paramagnetic resonance (EPR) spectroscopy. The useful dose range of these pellets was found to ranges from 1 to 80 kGy. The stability of the radiation- induced response was also studied

  15. Resolving the limitations of using glycine as EPR dosimeter in the intermediate level of gamma dose

    Science.gov (United States)

    Aboelezz, E.; Hassan, G. M.

    2018-04-01

    The dosimetric properties of the simplest amino acid "glycine"- using EPR technique- were investigated in comparison to reference standard alanine dosimeter. The EPR spectrum of glycine at room temperature is complex, but immediately after irradiation, it appears as a triplet hyperfine structure probably due to the dominant contribution of the (•CH2COO-) radical. The dosimetric peak of glycine is at g-factor 2.0026 ± 0.0015 and its line width is 9 G at large modulation amplitude (7 G). The optimum microwave was studied and was found to be as alanine 8 mW; the post-irradiation as well as the dose rate effects were discussed. Dosimetric peak intensity of glycine fades rapidly to be about one quarter of its original value during 20 days for dried samples and it stabilizes after that. The dose response study in an intermediate range (2-1000 Gy) reveals that the glycine SNR is about 2 times more than that of alanine pellets when measured immediately after irradiation and 4 times more than that of glycine itself after 22 days of irradiation. The effect of energy dependence was studied and interpreted theoretically by calculation of mass energy absorption coefficient. The calculated combined uncertainties for glycine and alanine are nearly the same and were found to be 2.42% and 2.33%, respectively. Glycine shows interesting dosimetric properties in the range of ionizing radiation doses investigated.

  16. 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...... methods the proposed algorithm can be applied without normalisation of phase shifts caused by changes in the g-value of the cavity. The study shows that alanine dosimetry is a suitable candidate for medical reference dosimetry especially for quality control applications.......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...

  17. Characterization of the factors having an influence on the evolution of the EPR signal of irradiated alanine

    International Nuclear Information System (INIS)

    Feaugas-Le-Berre, Valerie

    1999-01-01

    EPR/alanine dosimetry has been used by the LNHB (Laboratoire National Henri Becquerel) since many years for applied metrology. This technic is based on the measurement of the EPR signal of the free radicals induced in alanine by irradiation. The aim of this work is to characterize the factors having an influence on the evolution of the amplitude of the EPR signal of irradiated alanine to limit the uncertainties on the determination of the absorbed dose. The first step of this work has been the choice of the dosimeter. A bibliographic study completed by experiments on the response of alanine isomers to the dose and on its stability with time has lead us to choose L-α-alanine powder as dosimeter. The influence of the recording parameter of the spectrometer on the characteristics of the EPR spectrum has then been studied. This has enabled us to optimize the recording conditions of EPR spectra. As the angular anisotropy of the EPR signal limits the measurements reproducibility, an experimental protocol has been defined to solve this problem. The repeatability of the measurements has been enhanced by modifying the spectrometer and using an internal standard constituted of single crystals of CuSO 4 .5H 2 O. As the amplitude of the EPR signal is sensitive to the measurement temperature, a method of normalization of the results to 20 C has been determined. We have studied the influence of an irradiation parameter and of environmental parameters. We have shown that the EPR signal amplitude increases with irradiation temperature. The EPR signal amplitude and its evolution vary strongly with storage conditions (temperature and moisture) of the dosimeter before and after irradiation. The presence of moisture in alanine powder leads to a loss of signal amplitude. The dosimeters exposition to light also entails a loss of amplitude. Oxygen does not influence the EPR spectrum of alanine. We have noticed that the EPR signal amplitude of samples stored in absence of moisture

  18. EPR response of sucrose and microcrystalline cellulose to measure high doses of gamma radiation; Respuesta EPR de sacarosa y celulosa micro cristalina para medir altas dosis de radiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Torijano, E.; Cruz, L.; Gutierrez, G.; Azorin, J.; Aguirre, 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)

    2015-10-15

    Solid dosimeters of sucrose and microcrystalline cellulose (Avicel Ph-102) were prepared, following the same process, in order to compare their EPR response against that of the l-alanine dosimeters considered as reference. All lots of dosimeters were irradiated with gamma radiation in Gamma beam irradiator with 8 kGy/h of the Nuclear Sciences Institute of UNAM. Doses ranged from 1 to 10 kGy respectively. We found that both the response of sucrose as microcrystalline cellulose were linear; however, the response intensity was, on average, twenty times more for sucrose. Comparing this against the EPR response of l-alanine in the range of doses, it was found that the response to sucrose is a third part; and microcrystalline cellulose is a sixtieth, approximately. The results agree with those found in the literature for sucrose, leaving open the possibility of investigating other dosage ranges for cellulose. (Author)

  19. Physico-chemical studies for strontium sulfate radiation dosimeter

    Directory of Open Access Journals (Sweden)

    M.A.H. Rushdi

    2015-04-01

    Full Text Available Anhydrous strontium sulfate (SrSO4 has shown a promise candidate as a dosimeter for low dose applications producing unique EPR signals with γ-rays which it has a linear response relationship (r2 = 0.999 in the range of 1–100 Gy. The present study extended to evaluate the properties of strontium sulfate dosimeter in intermediate dose range of technology applications. It was observed that the intensity of the EPR signal at g = 2.01081 increases with a 3rd polynomial function in the range of 0.10–15 kGy. In addition, the radical (SO4− provides a stable signal with a good reproducibility (0.107%. Other physics characteristic including the collision of mass stopping power dependence of the system and the effect of atomic number in different energy regions were investigated. The uncertainty budget for high doses has obtained from the measurement with value of 3.57% at 2σ confidence level.

  20. The photon energy dependence of the alanine/EPR dosimetry system, an experimental investigation

    International Nuclear Information System (INIS)

    Bergstrand, E.S.; Hole, E.O.; Shortt, K.R.; Ross, C.K.

    2002-01-01

    The energy dependence of a dosimetry system based on electron paramagnetic resonance (EPR) spectroscopy of alanine has been studied to determine its suitability for use in dose verification for radiotherapy. A few experiments with high-energy photon irradiation of alanine have been reported in the literature. However, the reported results disagree whether the ratio of dose in alanine to dose in water is independent of the radiation energy or whether there is a small dependence for photon energies of relevance to radiotherapy. The concentration of free radicals in alanine is proportional to the absorbed dose in alanine over a wide dose range covering three decades. The relative number of radicals may be determined by examining the EPR spectrum, and hence it is possible to determine the dose with a system that has been calibrated using a known dose of 60 Co radiation. In the present work, irradiations of alanine dosimeters were performed at the National Research Council (NRC), in Ottawa, Canada. The radiation qualities investigated were 10, 20 and 30 MV x-rays using the NRC linac. For each radiation quality, 30 dosimeters were irradiated in a water phantom with a level of absorbed dose to water ranging from 10 to 50 Gy. For reference purposes, irradiations using the NRC 60 Co source were performed on more or less the same day as the irradiations at each specific linac quality. In all beams, the dose to water was measured using a graphite-walled NE2571 ionisation chamber that was originally calibrated by comparison with a sealed-water calorimeter. The alanine dosimeters were evaluated at the EPR laboratory at the University of Oslo, Norway, using an X-band Bruker ESP300E spectrometer with a rectangular double resonator. One of the resonators contained a Mn 2+ /MgO sample that was read after each dosimeter reading, in order to provide independence from short-term sensitivity fluctuations in the spectrometer. All dosimeters irradiated at one specific linac quality were

  1. EPR-dosimetry for radiation processing of food

    International Nuclear Information System (INIS)

    Peimel-Stuglik, Z.; Fabisiak, S.

    2002-01-01

    The usefulness of two, easy accessible alanine-polymer dosimeters to low (D ≤ 10 kGy) ionizing radiation dose measurements, were investigated. In both cases (ALANPOL from IChTJ and foil dosemeters from Gamma Service, Radeberg, Germany) the results were positive. EPR-alanine method based on the described dosimeters meets the requirements to use it in radiation processing of food. Thin foil dosemeters from Gamma Service are recommended mainly for dose distribution measurements. ALANPOL - for routine use. The advantage of ALANPOL is lower price, higher sensitivity and high resistance to unfavourable environmental conditions, including water. (author)

  2. EPR response of sucrose and microcrystalline cellulose to measure high doses of gamma radiation

    International Nuclear Information System (INIS)

    Torijano, E.; Cruz, L.; Gutierrez, G.; Azorin, J.; Aguirre, F.; Cruz Z, E.

    2015-10-01

    Solid dosimeters of sucrose and microcrystalline cellulose (Avicel Ph-102) were prepared, following the same process, in order to compare their EPR response against that of the l-alanine dosimeters considered as reference. All lots of dosimeters were irradiated with gamma radiation in Gamma beam irradiator with 8 kGy/h of the Nuclear Sciences Institute of UNAM. Doses ranged from 1 to 10 kGy respectively. We found that both the response of sucrose as microcrystalline cellulose were linear; however, the response intensity was, on average, twenty times more for sucrose. Comparing this against the EPR response of l-alanine in the range of doses, it was found that the response to sucrose is a third part; and microcrystalline cellulose is a sixtieth, approximately. The results agree with those found in the literature for sucrose, leaving open the possibility of investigating other dosage ranges for cellulose. (Author)

  3. 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)

  4. 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)

  5. Alanine-EPR dosimetry system. Why we like it?

    International Nuclear Information System (INIS)

    Stuglik, Z.

    2007-01-01

    To develop a new high-dose dosimeter we should: (1) to find material with radiation effect monotonically (if possible linearly) dependent on an absorbed dose; (2) to investigate its dosimetric characteristics (sensitivity, dose range, repeatability, accuracy, post-effects); (3) to evaluate economical parameters of new method (cost and availability of dosimetric material, cost of analytical instrument and its services); (4) to evaluate operational features of new dosimeter (sensitivity for environmental conditions, time from irradiation to the read-out); (5) to perform a calibration curve, i.e. functional dependence between radiation effect (dosimetric signal) and absorbed dose. On the base of this very stable stable ammonium radical (SAR) generated in crystalline α-alanine was established in the INCT as an alanine-EPR dosimetry system. Presented lecture describes the main features of this dosimeter

  6. Dosimetry in non-homogeneous media with alanine/EPR mini dosemeters and simulation with PENELOPE Monte Carlo code

    International Nuclear Information System (INIS)

    Vega Ramirez, J.L.; Chen, F.; Nicolucci, P.; Baffa, O.

    2009-01-01

    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 60 Co radiotherapy unit using 80 cm source skin distance and field sizes of 2.5 x 2.5 cm 2 . The inhomogeneous phantom consisted of acrylic and cork sheets of 30 x 30 x 1 cm 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)

  7. Low-cost commercial glass beads as dosimeters in radiotherapy

    International Nuclear Information System (INIS)

    Jafari, S.M.; Bradley, D.A.; Gouldstone, C.A.; Sharpe, P.H.G.; Alalawi, A.; Jordan, T.J.; Clark, C.H.; Nisbet, A.; Spyrou, N.M.

    2014-01-01

    Recent developments in advanced radiotherapy techniques using small field photon beams, require small detectors to determine the delivered dose in steep dose gradient fields. Commercially available glass jewellery beads exhibit thermoluminescent properties and have the potential to be used as dosimeters in radiotherapy due to their small size ( 60 Co gamma rays over doses ranging from 1 to 2500 cGy. A thermoluminescence (TL) system and an electron paramagnetic resonance (EPR) system were employed for read out. Both the TL and EPR studies demonstrated a radiation-induced signal, the sensitivity of which varied with bead colour. White coloured beads proved to be the most sensitive for both systems. The smallest and therefore least sensitive bead sizes allowed measurement of doses of 1 cGy using the TL system while that for the EPR system was approximately 1000 cGy. The fading rate was found to be 10% 30 days after irradiation with both readout systems. The dose response is linear with measured dose over the dose range 1 to 2500 cGy, with an R 2 correlation coefficient of greater than 0.999. The batch-to-batch reproducibility of a set of dosimeters after a single irradiation was found to be 3% (1 SD). The reproducibility of individual dosimeters was found to be 1.7%. No measurable angular dependence was found (results agreed within 1%). Dose rate response was found to agree within 1% for dose rates of 100 to 600 cGy/min. These results demonstrate the potential use of glass beads as TL dosimeters over the dose range commonly applied in radiotherapy. - Highlights: • We examined the dosimetric properties of a low cost commercially produced glass seed beads. • Glass beads are available in small size of 1–3 mm, suitable for dosimetry of small radiation fields. • The results demonstrate a mean reproducibility of 0.23% (2 SD), batch homogeneity of within 5%. • Dose response was linear over wide dose range tested for 1 cGy to kGy. • Improved fading effect of 10

  8. 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.

  9. Study of dosimetric properties of acetylsalicylic acid in pharmaceutical preparations by EPR spectroscopy

    International Nuclear Information System (INIS)

    Juarez Calderon, J.M.; Negron Mendoza, A.; Ramos Bernal, S.; Gomez Vidales, V.

    2008-01-01

    Electron paramagnetic resonance (EPR) was used to investigate the dosimetric properties of two pharmaceutical preparations containing acetylsalicylic acid, Aspirin (trademark) and Cafiaspirin (trademark). The EPR spectra of the irradiated samples were found to have an asymmetric absorption characterized by a major resonance at g = 2.0033. Dose response was investigated between dose ranges of 2 to 40 kGy for 60 Co-gamma rays. Fading characteristics and dependence on temperature irradiation were also studied. We suggest that commercial Aspirin (trademark) and Cafiaspirin (trademark) tablets can be used as dosimeters for industrial processes. (author)

  10. A system for remote dosimetry audit of 3D-CRT, IMRT and VMAT based on lithium formate dosimetry

    International Nuclear Information System (INIS)

    Adolfsson, Emelie; Gustafsson, Håkan; Lund, Eva; Alm Carlsson, Gudrun; Olsson, Sara; Carlsson Tedgren, Åsa

    2014-01-01

    Summary: The aim of this work was to develop and test a remote end-to-end audit system using lithium formate EPR dosimeters. Four clinics were included in a pilot study, absorbed doses determined in the PTV agreed with TPS calculated doses within ±5% for 3D-CRT and ±7% (k = 1) for IMRT/VMAT dose plans

  11. EPR dosimetry of glass substrate of mobile phone LCDs

    International Nuclear Information System (INIS)

    Trompier, F.; Della Monaca, S.; Fattibene, P.; Clairand, I.

    2011-01-01

    Previous studies have shown that mineral glass from watches, windows and displays of personal electronic devices could be a suitable restrospective dosimeter in case of radiation accident. In this paper glass substrates of the window display of 100 mobile phones of different trademarks were analized by X-band cw-EPR before and after irradiation at 100 Gy. The objective of this study was to highlight some issues of EPR measurements of glass related to inter-sample variability of: i) signal line shape in irradiated and unirradiated glass; ii) signal intensity loss and line shape change with post-irradiation time; iii) signal changes induced by sample preparation and iv) signal changes induced by thermal annealing. Scope of the paper is to provide a phenomenological picture of the observed effects in order to give a warning about possible problems and to provide suggestions for future work. Explanation of the mechanisms and the causes leading to the observed effects was beyond the scope of this work. These preliminary results confirm that glass substrate of mobile phone displays should be considered as a fortuitous dosimeter in radiation accidents. However, albeit very promising, mineral glass presents a number of issues that should be thoroughly investigated and addressed in future work.

  12. EPR and UV spectrometry investigation of sucrose irradiated with carbon particles

    International Nuclear Information System (INIS)

    Karakirova, Yordanka; Yordanov, Nicola D.

    2010-01-01

    Solid state/EPR (SS/EPR) dosimeters of carbon ions irradiated sucrose are studied with EPR, and their water solutions - with UV spectroscopy. Doses between 20 and 200 Gy are used with linear energy transfer (LET) values for carbon ions of 63, 77, 96 and 230 keV μm -1 . After irradiation all samples show typical for irradiated sucrose EPR and UV spectra. The obtained data are compared with those previously reported for nitrogen particles and gamma rays irradiated sucrose. The identical shape of both the EPR and UV spectra of irradiated with various type radiation samples suggests that generated free radicals are not influenced by the nature of radiation. The lack of difference in the line width of the separate lines or the whole EPR spectrum, obtained for gamma and heavy particles irradiation, suggests negligible spin-spin interaction among the radiation-generated free radicals in the samples. The linear dependence of the EPR response on the absorbed dose radiation is found to be higher when generated by gamma rays, than by the same absorbed dose of heavy particles. In addition, the EPR response for carbon ions is higher than that for nitrogen ions. Water solutions of irradiated sucrose exhibit UV spectrum with absorption maximum at 267 nm, attributed to the recombination products of free radicals. The UV band intensity depends on the absorbed dose radiation. The UV spectra obtained for carbon, nitrogen and gamma rays irradiated sucrose are also compared.

  13. Study of dosimetric properties of acetylsalicylic acid in pharmaceutical preparations by EPR spectroscopy

    International Nuclear Information System (INIS)

    Juarez-Calderon, J.M.; Negron-Mendoza, A.; Ramos-Bernal, S.; Gomez-Vidales, V.

    2009-01-01

    Electron paramagnetic resonance (EPR) was used to investigate the dosimetric properties of two pharmaceutical preparations containing acetylsalicylic acid, Aspirin R and Cafiaspirin R . The EPR spectra of the irradiated samples were found to have an asymmetric absorption characterized by a major resonance at g = 2.0033. Dose response was investigated between dose ranges of 2 to 95 kGy for 60 Co-gamma rays. Fading characteristics and dependence on temperature irradiation were also studied. We suggest that commercial Aspirin R and Cafiaspirin R tablets can be used as dosimeters in the case of a short accident. (author)

  14. Development of an alanine dosimeter for gamma dosimetry in mixed environments

    International Nuclear Information System (INIS)

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

    1992-01-01

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

  15. 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.

  16. The Response of Alanine Dosimeters in Thermal Neutron Fields

    DEFF Research Database (Denmark)

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

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

  17. Development of a dosimeter for high doses assessment based on Alanine/EPR

    International Nuclear Information System (INIS)

    Galante, O.L.; Rodrigues, O. Jr.; Campos, L.L.

    2000-01-01

    The increasing use of radiation sources of high activity for industrial and medical applications becomes important the research and the development of detectors and dosimetric methods for quality control of the applied doses. This work presents the current stage of the research at IPEN/CNEN-SP that has as objective the development of a standard dosimetric system for high doses assessment based on the alanine as radiation detector and electron paramagnetic resonance (EPR) as measurement technique. The developed system consists of the cylindrical container built in polyethylene of high density and the detector element based on DL-alanine commercially available. For the detector preparation different binding materials such as paraffin and acetate polyvinyl solution (pva) and also the use of a polyethylene tube of low density with 3.2 mm of external diameter, 2 mm of internal diameter and 30 mm of length were tested to provide the easier preparation method and the most sensitive detector. For the alanine + paraffin detector it was used 80% of alanine and 20% of paraffin, for the alanine + pva detector it was used 70% of alanine and 30% of pva solution, and pure alanine was encapsulated, compacted and sealed in the case of the polyethylene tube. The obtained results with respect to handling, packing and construction easiness showed that the polyethylene tube presents all characteristics to obtain of a good detector element. The validation of the dosimetric system was carried out with gamma radiation of the cobalt-60 with doses in the range between 0.2 Gy to 200 kGy. Type tests such as fading, lowest detection limit, reproducibility and energy dependence of the sign EPR were performed. All measurements were carried out at room temperature using a spectrometer of electron paramagnetic resonance (EPR) Bruker model MXE. Taking into account the results obtained: linearity of the EPR signal between 10 Gy and 50 kGy, reproducibility better than 3%, low fading associated with

  18. EPR spectroscopy as a potential approach to identify irradiated food and radiation dosimetry - an overview

    International Nuclear Information System (INIS)

    Sanyal, Bhaskar; Chawla, S.P.

    2017-01-01

    The need for reliable and routine tests to determine whether or not food has been irradiated has arisen as a result of the progress made in commercialization of the food irradiation technology. The effectiveness of food irradiation depends on proper delivery of absorbed dose and its reliable measurement. Electron Paramagnetic Resonance (EPR) spectroscopy has been established as an essential tool both for detection of irradiated food and radiation measurements. This presentation demonstrates the behavior of the radicals produced in irradiated cashew nut and orange. In addition the role of EPR spectroscopy will be discussed to understand thermoluminescence behavior of CaSO 4 dosimeter. Cashew nut and orange samples were exposed to gamma radiation in the dose range of 0.25 to 2 kGy. CaSO 4 crystals were irradiated at 0.5-7 kGy. Electron Paramagnetic Resonance (EPR) spectroscopy was carried out using EMX model EPR spectrometer (BRUKER, Germany) with a microwave frequency of 9.42 GHz

  19. In Quest of the Alanine R3 Radical: Multivariate EPR Spectral Analyses of X-Irradiated Alanine in the Solid State.

    Science.gov (United States)

    Jåstad, Eirik O; Torheim, Turid; Villeneuve, Kathleen M; Kvaal, Knut; Hole, Eli O; Sagstuen, Einar; Malinen, Eirik; Futsaether, Cecilia M

    2017-09-28

    The amino acid l-α-alanine is the most commonly used material for solid-state electron paramagnetic resonance (EPR) dosimetry, due to the formation of highly stable radicals upon irradiation, with yields proportional to the radiation dose. Two major alanine radical components designated R1 and R2 have previously been uniquely characterized from EPR and electron-nuclear double resonance (ENDOR) studies as well as from quantum chemical calculations. There is also convincing experimental evidence of a third minor radical component R3, and a tentative radical structure has been suggested, even though no well-defined spectral signature has been observed experimentally. In the present study, temperature dependent EPR spectra of X-ray irradiated polycrystalline alanine were analyzed using five multivariate methods in further attempts to understand the composite nature of the alanine dosimeter EPR spectrum. Principal component analysis (PCA), maximum likelihood common factor analysis (MLCFA), independent component analysis (ICA), self-modeling mixture analysis (SMA), and multivariate curve resolution (MCR) were used to extract pure radical spectra and their fractional contributions from the experimental EPR spectra. All methods yielded spectral estimates resembling the established R1 spectrum. Furthermore, SMA and MCR consistently predicted both the established R2 spectrum and the shape of the R3 spectrum. The predicted shape of the R3 spectrum corresponded well with the proposed tentative spectrum derived from spectrum simulations. Thus, results from two independent multivariate data analysis techniques strongly support the previous evidence that three radicals are indeed present in irradiated alanine samples.

  20. Heavy-ion-induced sucrose radicals investigated using EPR and UV spectroscopy

    Science.gov (United States)

    Nakagawa, Kouichi; Karakirova, Yordanka; Yordanov, Nicola D.

    2015-01-01

    The potential use of a sucrose dosimeter for estimating both linear energy transfer (LET) and the absorbed dose of heavy ion and X-ray radiation was investigated. The stable free radicals were produced when sucrose was irradiated with heavy ions, such as helium, carbon, silicon and neon ions, and when the X-ray radiation was similar to the obtained electron paramagnetic resonance (EPR) spectra, which were ∼7 mT wide and composed of several hyperfine structures. In addition, the total spin concentration resulting from heavy-ion irradiation increased linearly as the absorbed dose increased, and decreased logarithmically as the LET increased. These empirical relations imply that the LET at a certain dose can be determined from the spin concentration. For sucrose and alanine, both cross-sections following C-ion irradiation with a 50 Gy dose were ∼1.3 × 10−12 [μm2], taking into account the molecular size of the samples. The values of these cross-sections imply that multiple ionizing particles were involved in the production of stable radicals. Furthermore, UV absorbance at 267 nm of an aqueous solution of irradiated sucrose was found to linearly increase with increasing absorbed dose. Therefore, the EPR and UV results suggest that sucrose can be a useful dosimeter for heavy-ion irradiation. PMID:25480828

  1. Plastic dosimeter

    International Nuclear Information System (INIS)

    Nagai, Shiro; Matsuda, Kohji.

    1988-01-01

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

  2. The analogy in the formation of hardness salts and gallstones according to the EPR study

    Science.gov (United States)

    Pichugina, Alina; Tsyro, Larisa; Unger, Felix

    2017-11-01

    The article shows that the hardness salts contain the same crystalline phases as the bile stone pigment. The identity of EPR spectra of hardness salts and pigment of gallstones containing calcium carbonate was established. An analogy between the processes of formation of hardness salts and gallstones is played, in which particles with open spin-orbitals (fermions) play a decisive role.

  3. EPR dosimetric properties of nano-barium sulfate

    International Nuclear Information System (INIS)

    Aboelezz, E.; Hassan, G.M.; Sharaf, M.A.; El-Khodary, A.

    2015-01-01

    Nano/micro BaSO 4 were prepared through the co-precipitation method to measure ionizing radiation doses using electron paramagnetic resonance (EPR). The nano-BaSO 4 sample was characterized using X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques. The dose response and fading properties of nano- and micro-phase BaSO 4 were compared in EPR spectra. The prepared nano- and micro-BaSO 4 samples have the same hole and electron centers, which may be attributed to SO 4 − and SO 3 − , respectively. The dosimetric signals for prepared nano- and micro-BaSO 4 have spectroscopic splitting factor (g) with values 2.0025±0.0006 and 2.0027±0.0006, respectively. The nanocrystalline sample has a linear γ-ray dose response over the range 0.4 Gy–1 kGy. The performance parameters which including detection limit and critical level calculated from weighted and unweighted least-squares fitting. The sensitivity of nano-BaSO 4 to γ-ray is one and a half times more than alanine. The lifetime and activation energy for nano-BaSO 4 were estimated by conducting a thermal stability study, and were 5.7±1.1×10 4 years and 0.73±0.14 eV, respectively. The combined and expanded uncertainties accompanying measurements were ±3.89% and ±7.78%, respectively. - Highlights: • Preparation of nano-BaSO 4 using the co-precipitation method. • Study of the dosimetric properties of nano-barium sulfate using the EPR technique. • Comparison between a new EPR dosimeter using nano-materials and standard alanine. • Calculation of the uncertainty budget for nano-BaSO 4

  4. Radiation sensitivity and EPR dosimetric potential of gallic acid and its esters

    International Nuclear Information System (INIS)

    Tuner, Hasan; Oktay Bal, M.; Polat, Mustafa

    2015-01-01

    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. - Highlights: • Radiation sensitivity of gallic acid and its esters were studied in intermediate and low radiation dose range using EPR. • While the irradiated samples of GA were presented complex EPR spectra the esters presented singlet ESR spectra. • Samples were compared to alanine in terms of the dosimetric point of view. • The radiation sensitivities of the investigated materials were very low at intermediate doses. • Lauryl ester of gallic acid was found to present a good sensitivity below 10 Gy

  5. Photochemical reduction of water-soluble C60 derivatives (EPR study)

    International Nuclear Information System (INIS)

    Brezova, V.; Stasko, A.; Dvoranova, D.; Asmus, K.D.; Guldi, D.M.

    1999-01-01

    The photochemical reduction of three bis-functionalized C 60 derivatives resulted in the formation of a single radical product, characterized by relatively narrow EPR line (g M = 2.0007, pp < 0.02 mT). In the irradiated aqueous solutions containing L-ascorbic acid, in the addition to the EPR line related to bis-adduct mono-anion, also 6-line EPR spectrum of ascorbyl radical was observed. Consequently, the photoinduced formation of ascorbyl radical was attributed to the intermolecular quenching of fullerenes excited states. (authors)

  6. EPR Spectroscopy in Environmental Lichen-Indication

    Science.gov (United States)

    Bondarenko, P. V.; Nguyet, Le Thi Bich; Zhuravleva, S. E.; Trukhan, E. M.

    2017-09-01

    The paramagnetic properties of lichens were investigated using EPR spectroscopy and Xanthoria parietina (L.) Th. Fr. as a case study. It was found that the concentration of paramagnetic centers in lichen thalli increased as the air-pollution level increased. Possible formation mechanisms of the paramagnetic centers in lichens were discussed. The efficiency of using EPR spectroscopy to study lichens as environmental quality indicators was demonstrated.

  7. Medical reference dosimetry using EPR measurements of alanine: Development of an improved method for clinical dose levels

    International Nuclear Information System (INIS)

    Helt-Hansen, Jakob; Andersen, Claus Erik; Rosendal, Flemming; Kofoed, Inger Matilde

    2009-01-01

    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 signal fading, non-destructive measurement and small dosimeter size. Material and Methods. A Bruker EMX-micro EPR spectrometer with a rectangular cavity and a measurement time of two minutes per dosimeter was used for reading of irradiated alanine dosimeters. Under these conditions a new algorithm based 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. The typical difference between the dose measured with alanine in solid water and the dose measured with an ion chamber in a water tank was about 1%. A difference of 2% between 6 and 18 MV was found, possibly due to non-water equivalence of the applied phantom. Discussion. Compared to previously published methods the proposed algorithm can be applied without normalisation of phase shifts caused by changes in the g-value of the cavity. The study shows that alanine dosimetry is a suitable candidate for medical reference dosimetry especially for quality control applications

  8. EPR study of N+-ion-induced free radical formation in antibiotic-producers

    International Nuclear Information System (INIS)

    Xie Liqing; Zhang Yinfen; Chen Ruyi; Gao Juncheng; Zhang Peiling; Ying Hengfeng.

    1995-01-01

    Under the room temperature, electron paramagnetic resonance (EPR) spectrometer was used to study free radical formation in antibiotic-producers in order to investigate antibiotic-producer mutagenic breeding, which were induced by N + ion implanting into antibiotic-producers (e.g., Streptomyces ribosidificus, Streptomyces kanamyceticus and the phage-resistant culture of Streptomyces kanamyceticus). The results show that a lot of free radicals can be induced by N + ion implanting into antibiotic-producers, and the yields of the free radicals increase with implanting dose. The death rate of antibiotic-producers rises due to the increase of N + -ion-induced free radical yields. (author)

  9. Potential use of wallboard (drywall) for EPR retrospective dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Jeroen W. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, 1280 Main St. West, Hamilton ON L8S 4K1 (Canada)], E-mail: thompjw@mcmaster.ca; Atiya, Ibrahim Abu [Department of Medical Physics and Applied Radiation Sciences, McMaster University, 1280 Main St. West, Hamilton ON L8S 4K1 (Canada)], E-mail: abuatii@mcmaster.ca; Rink, W. Jack [School of Geography and Earth Sciences, McMaster University, 1280 Main St. West, Hamilton ON L8S 4K1 (Canada)], E-mail: rinkwj@mcmaster.ca; Boreham, Doug [Department of Medical Physics and Applied Radiation Sciences, McMaster University, 1280 Main St. West, Hamilton ON L8S 4K1 (Canada)], E-mail: boreham@mcmaster.ca

    2009-03-15

    Concern regarding the possibility of criminal or terrorist use of nuclear materials has led to an interest in developing the capability to measure radiation dose in a variety of natural and manufactured materials. Electron paramagnetic resonance (EPR) measurements of radiation dose following a radiological incident may aid in screening affected populations (triage) and in reconstruction of doses following accidents. One such EPR dosimeter is wallboard (drywall), a common construction material composed largely of gypsum (calcium sulphate dihydrate). We have identified the CO{sub 3}{sup -} and SO{sub 3}{sup -} dose-sensitive lines in drywall and developed a measurement protocol using the intensity of CO{sub 3}{sup -} line. Proper background subtraction is a major difficulty, and we demonstrate a procedure based on alignment of a contaminant Mn{sup 2+} line. As a proof-of-concept, a wallboard panel was irradiated with a {sup 60}Co source, and a two-dimensional map of the absorbed dose was measured. While most aliquots yielded reasonably accurate doses, a spatially contiguous region of apparent dose-insensitivity in one panel was identified.

  10. Polymer therapeutics and the EPR effect.

    Science.gov (United States)

    Maeda, Hiroshi

    History of the EPR (enhanced permeability and retention) effect is discussed, which goes back to the analyses of molecular pathology in bacterial infection and edema (extravasation) formation. The first mediator we found for extravasation was bradykinin. Later on, were found nitric oxide and superoxide, then formation of peroxynitrite, that activates procollagenase. In this inflammatory setting many other vascular mediators are involved that are also common to cancer vasculature. Obviously cancer vasculature is defective architechtally, and this makes macromolecular drugs more permeable through the vascular wall. The importance of this pathophysiological event of EPR effect can be applied to macromolecular drug-delivery, or tumor selective delivery, which takes hours to achieve in the primary as well as metastatic tumors, not to mention of the inflamed tissues. The retention of the EPR means that such drugs will be retained in tumor tissues more than days to weeks. This was demonstrated initially, and most dramatically, using SMANCS, a protein-polymer conjugated-drug dissolved in lipid contrast medium (Lipiodol) by administering intraarterially. For disseminating the EPR concept globally, or in the scientific community, Professor Ruth Duncan played a key role at the early stage, as she worked extensively on polymer- therapeutics, and knew its importance.

  11. Pen dosimeters

    CERN Multimedia

    SC/RP Group

    2006-01-01

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

  12. The EPR reactor

    International Nuclear Information System (INIS)

    Lacoste, A.C.; Dupuy, Ph.; Gupta, O.; Perez, J.R.; Emond, D.; Cererino, G.; Rousseau, J.M.; Jeffroy, F.; Evrard, J.M.; Seiler, J.M.; Azarian, G.; Chaumont, B.; Dubail, A.; Fischer, M.; Tiippana, P.; Hyvarinen, J.; Zaleski, C.P.; Meritet, S.; Iglesias, F.; Vincent, C.; Massart, S.; Graillat, G.; Esteve, B.; Mansillon, Y.; Gatinol, C.; Carre, F.

    2005-01-01

    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.)

  13. Studied by electron paramagnetic resonance (EPR) of polymethyl methacrylate (PMMA) irradiated with gamma photons from cobalt 60

    International Nuclear Information System (INIS)

    Jalali, Hajer

    2013-01-01

    Ionizing radiation is radiation able to deposit enough energy in the material through which they pass to create ionization. These ionizing radiations, when mastered, have many practical uses beneficial (areas of health, industry ...). Gamma rays are emitted by radioactive nuclei. The objective of our work is the study of polymethyl methacrylate (PMMA) irradiated by gamma photons from cobalt-60. To study the technique of radio spectroscopy (9 to 10Hz) electron paramagnetic resonance EPR is used. This technique is specific to characterize transient free radicals involved in chemical reactions such as oxidation, combustion, polymerization reactions ... We analyzed the EPR spectra three batch KS, EB, and JF our dosimeter according to the dose (high and low) and showed that the dosimetric response can be represented in exponential form (high dose) and linear form (low dose). We also studied the kinetics of decay of the EPR signal as a function of time (fading) and showed that the responses relating to stabilize after 20 min of irradiation.

  14. Composite material dosimeters

    Science.gov (United States)

    Miller, Steven D.

    1996-01-01

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

  15. Thermal induced EPR signals in tooth enamel

    International Nuclear Information System (INIS)

    Fattibene, P.; Aragno, D.; Onori, S.; Pressello, M.C.

    2000-01-01

    Electron paramagnetic resonance (EPR) spectroscopy was used to detect the effects of temperature on powdered human tooth enamel, not irradiated in the laboratory. Samples were heated at temperature between 350 and 450, at 600 and at 1000 deg. C, for different heating times, between 6 min and 39 h. Changes in the EPR spectra were detected, with the formation of new signals. Possible correlation between the changes in EPR spectra and modifications in the enamel and in the mineral phase of bone detected with other techniques is discussed. The implications for dosimetric applications of signals induced by overheating due to mechanical friction during sample preparation are underlined

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

    International Nuclear Information System (INIS)

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

    2002-01-01

    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 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)

  17. An experimental and Monte Carlo investigation of the energy dependence of alanine/EPR dosimetry: I. Clinical x-ray beams

    International Nuclear Information System (INIS)

    Zeng, G G; McEwen, M R; Rogers, D W O; Klassen, N V

    2004-01-01

    The energy dependence of alanine/EPR dosimetry, in terms of absorbed dose-to-water for clinical 6, 10, 25 MV x-rays and 60 Co rays was investigated by measurements and Monte Carlo (MC) calculations. The dose rates were traceable to the NRC primary standard for absorbed dose, a sealed water calorimetry. The electron paramagnetic resonance (EPR) spectra of irradiated pellets were measured using a Bruker EMX 081 EPR spectrometer. The DOSRZnrc Monte Carlo code of the EGSnrc system was used to simulate the experimental conditions with BEAM code calculated input spectra of x-rays and γ-rays. Within the experimental uncertainty of 0.5%, the alanine EPR response to absorbed dose-to-water for x-rays was not dependent on beam quality from 6 MV to 25 MV, but on average, it was about 0.6% lower than its response to 60 Co gamma rays. Combining experimental data with Monte Carlo calculations, it is found that the alanine/EPR response per unit absorbed dose-to-alanine is the same for clinical x-rays and 60 Co gamma rays within the uncertainty of 0.6%. Monte Carlo simulations showed that neither the presence of PMMA holder nor varying the dosimeter thickness between 1 mm and 5 mm has significant effect on the energy dependence of alanine/EPR dosimetry within the calculation uncertainty of 0.3%

  18. One-way EPR steering and genuine multipartite EPR steering

    Science.gov (United States)

    He, Qiongyi; Reid, Margaret D.

    2012-11-01

    We propose criteria and experimental strategies to realise the Einstein-Podolsky-Rosen (EPR) steering nonlocality. One-way steering can be obtained where there is asymmetry of thermal noise on each system. We also present EPR steering inequalities that act as signatures and suggest how to optimise EPR correlations in specific schemes so that the genuine multipartite EPR steering nonlocality (EPR paradox) can also possibly be realised. The results presented here also apply to the spatially separated macroscopic atomic ensembles.

  19. Radiation dosimeter

    International Nuclear Information System (INIS)

    Lowe, D.

    1980-01-01

    A radiation dosimeter is described, comprising a thermoluminescent phosphor incorporated in matrix of polyethersulphone. The dosimeter is preferably a thin film formed by spreading a suspension of a powdered phosphor in a solution of polyethersulphone onto a flat surface. The solvent for the polyethersulphone is a mixture of a n-methyl-2-pyrrolidone and xylene in equal proportions. A thin, inert film of polyethersulphone can be cemented to one surface of the dosimeter so as to provide a skin dosimeter. (author)

  20. Alanine dosimetry for clinical applications. Proceedings

    International Nuclear Information System (INIS)

    Anton, M.

    2006-05-01

    The following topics are dealt with: Therapy level alanine dosimetry at the UK Nationational Physical Laboratory, alanine as a precision validation tool for reference dosimetry, composition of alanine pellet dosimeters, the angular dependence of the alanine ESR spectrum, the CIAE alanine dosimeter for radiotherapy level, a correction for temporal evolution effects in alanine dosimetry, next-generation services foe e-traceability to ionization radiation national standards, establishing e-traceability to HIST high-dose measurement standards, alanine dosimetry of dose delivery from clinical accelerators, the e-scan alanine dosimeter reader, alanine dosimetry at ISS, verification of the integral delivered dose for IMRT treatment in the head and neck region with ESR/alanine dosimetry, alanine dosimetry in helical tomotherapy beams, ESR dosimetry research and development at the University of Palermo, lithium formate as a low-dose EPR radiation dosimeter, sensitivity enhancement of alanine/EPR dosimetry. (HSI)

  1. Dosimeter charging apparatus

    International Nuclear Information System (INIS)

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

    1985-01-01

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

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

    International Nuclear Information System (INIS)

    Al-Karmi, Anan M.; Zraiqat, Fadi

    2015-01-01

    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 3 solid water phantom and then irradiating on a linac with 6 MV photon beam at 10×10 cm 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

  3. Hydrogen yield from polyethylene by radiolysis and the application to dosimeter

    International Nuclear Information System (INIS)

    Seguchi, T.

    2006-01-01

    by annealing or heating treatment, so the precise experiments were conducted using UHM-PE. G(H 2 ) of PIS containing double bond is 0.7, which is around 15% of PE and EPR. H 2 yield increases linearly with dose until 30 kGy and gradually levels off from a proportional line. The starting point (30 kGy) of level off is much lower than the dose (3 MGy) estimated by hydrogen material balance in PE molecules. Hydrogen evolution means that double bonds and cross-linking are formed in PE molecules by radiolysis. The probability of double bond and cross-linking formation is estimated to be the same. The relation between hydrogen evolution and dose was analyzed using a model which the double bond formed in PE matrix by radiolysis acts to protect the radiation induced chemical reaction as a radiation stabilizer and the protection effect depends on the content of double bond. The equations and the parameters for the analysis were reported in a previous paper. The calculation indicated that one double bond reduces the hydrogen evolution in a certain volume of PE matrix, cubic of 1.6 nm radius from one double bond. The fact that a double bond reduces H 2 evolution is shown in PIS which contains one double bond per 5 carbons, and H 2 evolution is only 15% of that for poly-olefins without double bond. It had been reported that H 2 evolution from aromatic polymers which contain the conjugated double bond is very low, for example, G(H 2 ) is 0.03 for poly(ethylene-terephthalate). Also H 2 evolution from poly-olefins is reduced by mixing with a small amount of aromatic compounds. Then, the above model for the analysis of saturation phenomena in the radiolysis of polyethylene would be reasonable. The radiation energy should be transferred to vinyl groups like double bonds and conjugated double bonds and stabilized in the site, and then the chemical reactions are reduced. Application to dosimeter: UHM-PE has high viscosity above the melting temperature, and the morphology such as

  4. Free radical EPR in delineating oil bearing zones

    International Nuclear Information System (INIS)

    Sharma, R.K.; Kumar, V.; Das, T.K.; Gundu Rao, T.K.

    1993-01-01

    Presence of naturally occurring gamma ray activity has long been detected in oil/gas wells is invariably carried out for formation evaluation. Similarly, presence of free radicals in oil bearing formations has also been known for quite sometime. Present paper deals with a systematic study of detecting these free radicals in oil wells and correlations of these with x-ray and other logs for identification of hydrocarbon bearing zones. Present study attempts to establish EPR as as inexpensive and reliable tool in comparison with gamma ray and neutron density logs recorded in exploratory oil wells. EPR studies have been carried out in an exploratory well between depth intervals 1600 m-1400 m located in south of existing producing field in Bombay Offshore region. Based on these results, an EPR log has been prepared and compared with gamma ray and neutron density logs. (author). 4 refs., 1 fig., 1 tab

  5. EPR spectra of some irradiated polycrystalline perrhenate

    International Nuclear Information System (INIS)

    Zaitseva, N.G.; Constantinescu, M.; Georgescu, R.; Constantinescu, O.

    1978-10-01

    An EPR study of the paramagnetic centers formed by γ, electron and neutron irradiation of the NaReO 4 and KReO 4 was made. In the EPR spectra of the powder samples irradiated γ, with electrons and neutrons, the presence of three types of paramagnetic centers was observed. From the EPR parameters, the centers were attributed to the ReOsub(4)sup(.), ReOsub(3)sup(.) and ReOsub(2)sup(.) radicals respectively. The lower intensity of the spectra observed by KReO 4 samples irradiation showed a higher radioresistance of the KReO 4 than that of NaReO 4 . A radiolitical scheme taking into account the paramagnetic centers formation was proposed. (author)

  6. The NIM alanine-EPR dosimetry system: its application in NDAS programme and others

    International Nuclear Information System (INIS)

    Gao Jun-Cheng

    1999-01-01

    In 1983, National Institute of Metrology (NIM) began to study alanine-EPR dosimetry system. From 1988 on, the system has been used as a transfer standard to launch into the National Dose Assurance Service (NDAS) programme for cobalt-60 facilities in China. In this paper, the eleven years implementation of NDAS programme are presented by statistics. In 1991, under an IAEA coordinated research programme, NIM had studied to extend the range of the system to therapy level. In recent years, the NIM in cooperation with other institutes has been developing film-alanine dosimeter for electron beam dosimetry. (author)

  7. Verification of the pure alanine in PMMA tube dosimeter applicability for dosimetry of radiotherapy photon beams: a feasibility study.

    Science.gov (United States)

    Al-Karmi, Anan M; Ayaz, Ali Asghar H; Al-Enezi, Mamdouh S; Abdel-Rahman, Wamied; Dwaikat, Nidal

    2015-09-01

    Alanine dosimeters in the form of pure alanine powder in PMMA plastic tubes were investigated for dosimetry in a clinical application. Electron paramagnetic resonance (EPR) spectroscopy was used to measure absorbed radiation doses by detection of signals from radicals generated in irradiated alanine. The measurements were performed for low-dose ranges typical for single-fraction doses often used in external photon beam radiotherapy. First, the dosimeters were irradiated in a solid water phantom to establish calibration curves in the dose range from 0.3 to 3 Gy for 6 and 18 MV X-ray beams from a clinical linear accelerator. Next, the dosimeters were placed at various locations in an anthropomorphic pelvic phantom to measure the dose delivery of a conventional four-field box technique treatment plan to the pelvis. Finally, the doses measured with alanine dosimeters were compared against the doses calculated with a commercial treatment planning system (TPS). The results showed that the alanine dosimeters have a highly sensitive dose response with good linearity and no energy dependence in the dose range and photon beams used in this work. Also, a fairly good agreement was found between the in-phantom dose measurements with alanine dosimeters and the TPS dose calculations. The mean value of the ratios of measured to calculated dose values was found to be near unity. The measured points in the in-field region passed dose-difference acceptance criterion of 3% and those in the penumbral region passed distance-to-agreement acceptance criterion of 3 mm. These findings suggest that the pure alanine powder in PMMA tube dosimeter is a suitable option for dosimetry of radiotherapy photon beams.

  8. Development of Thermoluminescence Dosimeter CaSO4:Dy as Personal and Environmental Dosimeters

    International Nuclear Information System (INIS)

    Hasnel Sofyan

    2009-01-01

    Development of personal and environmental dosimeters using material phosphors of CaSO 4 :Dy powder in form capillary glass and disc teflon thermoluminescence (TL) dosimeter have been done. TL dosimeter CaSO 4 :Dy powder used can record dose response less than 0.01 mGy. Fading of TL dosimeter capillary glass after 29 days is 25%. In 1 batch, making of CaSO 4 :Dy powder can obtain 2 groups of dosimeter capillaries with coefficient variance smaller than 10%. This discrepancy caused difference in powder making and reading of the TL dosimeter. TL dosimeter CaSO 4 :Dy teflon disc with dia. 5 mm and 0.8 mm thickness is homogeneous mixture between phosphor powder with dia. 80 to 150 mesh and teflon powder dia. 20 μm. The composition of CaSO 4 :Dy and teflon in TL dosimeter influence sensitivity of the dosimeter. It’ concluded that in order to obtain optimal sensitivity of TL dosimeter, the composition of CaSO 4 :Dy and teflon is 3 and 1 with pressured of disc in 700 MPa. (author).

  9. IN-VIVO RADIATION DOSIMETRY USING PORTABLE L BAND EPR: ON-SITE MEASUREMENT OF VOLUNTEERS IN FUKUSHIMA PREFECTURE, JAPAN

    Science.gov (United States)

    Miyake, Minoru; Nakai, Yasuhiro; Yamaguchi, Ichiro; Hirata, Hiroshi; Kunugita, Naoki; Williams, Benjamin B.; Swartz, Harold M.

    2016-01-01

    The aim of this study was to make direct measurements of the possible radiation-induced EPR signals in the teeth of volunteers who were residents in Fukushima within 80 km distance from the Fukushima Nuclear Power plant at the time of the disaster, and continued to live there for at least 3 month after the disaster. Thirty four volunteers were enrolled in this study. These measurements were made using a portable L-band EPR spectrometer, which was originally developed in the EPR Center at Dartmouth. All measurements were performed using surface loop resonators that have been specifically designed for the upper incisor teeth. Potentially these signals include not only radiation-induced signals induced by the incident but also background signals including those from prior radiation exposure from the environment and medical exposure. We demonstrated that it is feasible to transport the dosimeter to the measurement site and make valid measurements. The intensity of the signals that were obtained was not significantly above those seen in volunteers who had not had potential radiation exposures at Fukushima. PMID:27522046

  10. In-vivo radiation dosimetry using portable L band EPR: on-site measurement of volunteers in Fukushima Prefecture, Japan

    International Nuclear Information System (INIS)

    Miyake, Minoru; Nakai, Yasuhiro; Yamaguchi, Ichiro; Kunugita, Naoki; Hirata, Hiroshi; Williams, Benjamin B.; Swartz, Harold M.

    2016-01-01

    The aim of this study was to make direct measurements of the possible radiation-induced EPR signals in the teeth of volunteers who were residents in Fukushima within 80 km distance from the Fukushima Nuclear Power plant at the time of the disaster, and continued to live there for at least 3 month after the disaster. Thirty four volunteers were enrolled in this study. These measurements were made using a portable L-band EPR spectrometer, which was originally developed in the EPR Center at Dartmouth. All measurements were performed using surface loop resonators that have been specifically designed for the upper incisor teeth. Potentially these signals include not only radiation-induced signals induced by the incident but also background signals including those from prior radiation exposure from the environment and medical exposure. We demonstrated that it is feasible to transport the dosimeter to the measurement site and make valid measurements. The intensity of the signals that were obtained was not significantly above those seen in volunteers who had not had potential radiation exposures at Fukushima. (authors)

  11. Alarm pocket dosimeter

    Energy Technology Data Exchange (ETDEWEB)

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

    1975-04-01

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

  12. Study on the angular dependence of personal exposure dosimeter - Focus on thermoluminescent dosimeter and photoluminescent dosimeter

    International Nuclear Information System (INIS)

    Dong, Kyung-Rae; Kweon, Dae Cheol; Chung, Woon-Kwan; Goo, Eun-Hoe; Dieter, Kevin; Choe, Chong-Hwan

    2011-01-01

    Radiation management departments place more emphasis on the accuracy of measurements than on the increase in the average dose and personal exposure dose from the use of radiation equipment and radioactive isotopes. Although current measurements are taken using devices, such as film badge dosimeters, pocket dosimeters and thermoluminescent dosimeters (TLDs), this study compared the angular dependence between the widely used TLDs and photoluminescent dosimeter (PLDs) in order to present primary data and evaluate the utility of PLD as a new dosimeter device. For X-ray fluoroscopy, a whole body phantom was placed on a table with a setting for the G-I technical factors fixed at a range of approximately 40 cm with a range of ±90 o at an interval scale of 15 o from the center location of an average radiological worker for PLDs (GD-450) and TLDs (Carot). This process was repeated 10 times, and at each time, the cumulative dosage was interpreted from 130 dosimeters using TLDs (UD-710R, Panasonic) and PLDs (FGD-650). The TLD and PLD showed a 52% and 23% decrease in the depth dosage from 0 o to -90 o , respectively. Therefore, PLDs have a lower angular dependence than TLDs.

  13. EPR dosimetry of radiotherapy photon beams in inhomogeneous media using alanine films

    Energy Technology Data Exchange (ETDEWEB)

    Oesteraas, Bjoern Helge [Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Montebello, N-0310 Oslo (Norway); Hole, Eli Olaug [Department of Physics, University of Oslo, PO Box 1048 Blindern, N-0316 Oslo (Norway); Olsen, Dag Rune [Department of Radiation Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, N-0310 Oslo (Norway); Malinen, Eirik [Department of Radiation Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, N-0310 Oslo (Norway)

    2006-12-21

    In the current work, EPR (electron paramagnetic resonance) dosimetry using alanine films (134 {mu}m thick) was utilized for dose measurements in inhomogeneous phantoms irradiated with radiotherapy photon beams. The main phantom material was PMMA, while either Styrofoam or aluminium was introduced as an inhomogeneity. The phantoms were irradiated to a maximum dose of about 30 Gy with 6 or 15 MV photons. The performance of the alanine film dosimeters was investigated and compared to results from ion chamber dosimetry, Monte Carlo simulations and radiotherapy treatment planning calculations. It was found that the alanine film dosimeters had a linear dose response above approximately 5 Gy, while a background signal obscured the response at lower dose levels. For doses between 5 and 60 Gy, the standard deviation of single alanine film dose estimates was about 2%. The alanine film dose estimates yielded results comparable to those from the Monte Carlo simulations and the ion chamber measurements, with absolute differences between estimates in the order of 1-15%. The treatment planning calculations exhibited limited applicability. The current work shows that alanine film dosimetry is a method suitable for estimating radiotherapeutical doses and for dose measurements in inhomogeneous media.

  14. EPR dosimetry of radiotherapy photon beams in inhomogeneous media using alanine films

    International Nuclear Information System (INIS)

    Oesteraas, Bjoern Helge; Hole, Eli Olaug; Olsen, Dag Rune; Malinen, Eirik

    2006-01-01

    In the current work, EPR (electron paramagnetic resonance) dosimetry using alanine films (134 μm thick) was utilized for dose measurements in inhomogeneous phantoms irradiated with radiotherapy photon beams. The main phantom material was PMMA, while either Styrofoam or aluminium was introduced as an inhomogeneity. The phantoms were irradiated to a maximum dose of about 30 Gy with 6 or 15 MV photons. The performance of the alanine film dosimeters was investigated and compared to results from ion chamber dosimetry, Monte Carlo simulations and radiotherapy treatment planning calculations. It was found that the alanine film dosimeters had a linear dose response above approximately 5 Gy, while a background signal obscured the response at lower dose levels. For doses between 5 and 60 Gy, the standard deviation of single alanine film dose estimates was about 2%. The alanine film dose estimates yielded results comparable to those from the Monte Carlo simulations and the ion chamber measurements, with absolute differences between estimates in the order of 1-15%. The treatment planning calculations exhibited limited applicability. The current work shows that alanine film dosimetry is a method suitable for estimating radiotherapeutical doses and for dose measurements in inhomogeneous media

  15. Direct detection of second harmonic and its use in alanine/EPR dosimetry

    International Nuclear Information System (INIS)

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

    2001-01-01

    In this work, the possible use of the second harmonic EPR signal from irradiated alanine for low radiation dose (∼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 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)

  16. Fundamentals of Polymer Gel Dosimeters

    Science.gov (United States)

    McAuley, Kim B.

    2006-12-01

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

  17. Dosimeter design specifications

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The combination dosimeter and security credential holder was developed as part of the effort involved to provide an automated readout and thermoluminescent dosimetry capability at Hanford. The holder is designed to accomodate the thermoluminescent dosimeter card, appropriate filters, the security credential and a snap type clip. The body of the holder is ABS plastic (acrylontrile-butadiene-styrene). The dosimeter holder and card is mold casted providing uniformity of construction

  18. EPR and Bell Locality

    OpenAIRE

    Norsen, Travis

    2004-01-01

    A new formulation of the EPR argument is presented, one which uses John Bell's mathematically precise local causality condition in place of the looser locality assumption which was used in the original EPR paper and on which Niels Bohr seems to have based his objection to the EPR argument. The new formulation of EPR bears a striking resemblance to Bell's derivation of his famous inequalities. The relation between these two arguments -- in particular, the role of EPR as part one of Bell's two-...

  19. Study of growth of polyaniline chain by EPR method

    Energy Technology Data Exchange (ETDEWEB)

    Kulikov, A V [Inst. of Chemical Physics, Chernogolovka (Russian Federation); Kogan, Ya L [Inst. of Chemical Physics, Chernogolovka (Russian Federation); Fokeeva, L S [Inst. of Chemical Physics, Chernogolovka (Russian Federation)

    1993-03-22

    Chemical aniline polymerization has been studied by the EPR method. After a long delay a weak EPR signal I is appeared and transformed rapidly into a strong Lorentzian line. Constants of spin exchange of signals I and II with paramagnetic probes Fe(CN)[sub 6][sup 3-], Co[sup 2+] and O[sub 2], freely diffusing in solution, have been determined. Effect of ferricyanide ions and urea, a breaker of hydrogen bonds, has been measured for signals I and II. Data obtained show the formation of an array of positive charges in PANI at early stage of doping. Constants of spin exchange depend on prehistory of samples. Averaging of EPR line widths of different paramagnetic centers in polyaniline was found. (orig.)

  20. On the Correlation between EPR and Positron Annihilation Measurements on gamma-Irradiated Acetyl Methionine

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard; Lund-Thomsen, E.; Mogensen, O. E.

    1972-01-01

    The dose dependence of the relative EPR signal intensity and positron lifetime spectrum was measured for γ‐irradiated acetyl methionine in the dose range from 0 to 30 Mrad. Angular correlation measurements were performed for the doses 0 and 30 Mrad. The result of the irradiation was the creation...... of EPR centers and inhibition of positronium formation. For one sample, irradiated with a dose of 30 Mrad, EPR and positron lifetime spectra were followed over a period of 50 days after the irradiation. The inhibiting effect and the EPR signal intensity decreased with time. No simple correlation could...... be established between the number of EPR centers and the positron annihilation data, but other possible explanations are discussed....

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

    Science.gov (United States)

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

    2018-04-11

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

  2. Kaolinite as an in situ dosimeter for past radionuclide migration at the Earth's surface

    International Nuclear Information System (INIS)

    Allard, T.; Muller, J.-P.

    1998-01-01

    The origin of 3 types of point defects (A-, Aminutes or feet- and B-centers) in kaolinite, due to natural irradiation and detected by electron paramagnetic resonance spectroscopy (EPR), has been demonstrated by artificial irradiation. The potential use of tracing the dynamics of the transfer of radionuclides through A-centers (i.e. the most stable centers) was qualitatively tested on different low-temperature alteration systems, some associated with U-concentrations. This paper proposes a quantitative approach to the reconstruction of the past migration of radionuclides by dosimetry of A-centers. With this aim in mind, the efficiency of α- and γ-radiations to produce A-centers was determined by experimental irradiation. Parameters extracted from A-center growth curves, together with their relationship with a parameter describing the degree of order of kaolinite, permitted (i) a definition to be made of the dose range in which a given kaolinite could be used as a dosimeter and (ii) the quantitative derivation of U-concentration from the cumulative dose (paleodose) of kaolinites. This was achieved by a formalism that accounted for the contribution of natural radiosources to the production of A-centers. The formalism was applied to the Nopal I U-deposit (Chihuhua, Mexico), considered as a natural analogue of a high level nuclear waste repository. Irrespective of the scenario considered, in terms of kaolinite age and of degree of isotopic disequilibrium in the system, A-center dosimetry permitted the determination of past occurrences of U which were several orders of magnitude higher than the present-day measured U-concentrations. Furthermore, this approach also provided evidence for several previous episodes of U-migration. EPR spectroscopy is thus a unique tool for the quantitative, indirect assessment of past radionuclide migration in the geosphere and kaolinite is a reliable in-situ dosimeter. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights

  3. 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

  4. Copper doped borate dosimeters revisited

    International Nuclear Information System (INIS)

    Alajerami, Y.S.M.; Hashim, S.; Ghoshal, S.K.; Bradley, D.A.; Mhareb, M.; Saleh, M.A.

    2014-01-01

    We render a panoramic overview on copper (Cu) doped borate dosimeters. Preparing a dosimeter by mixing specific materials with precise weights and methods is a never-ending quest. The recommended composition is highly decisive for accurate estimation of the absorbed dose, prediction of the biological outcome, determination of the treatment dose for radiation therapy and facilitation of personal monitoring. Based on these principles, the proposed dosimeter must cover a series of dosimetric properties to realize the exact results and assessment. The doped borate dosimeters indeed demonstrate attractive thermoluminescence (TL) features. Several dedicated efforts are attempted to improve the luminescence properties by doping various transition metals or rare-earth elements. The Cu ion being one of the preferred activators shows excellent TL properties as revealed via detail comparison with other dosimeters. Two oxide states of Cu (Cu + and Cu ++ ) with reasonable atomic number allow easy interaction with boron network. Interestingly, the intrinsic luminescent centers of borate lattice are in cross linked with that of Cu + ions. Thus, the activation of borate dosimeter with Cu ions for the enhancement of the TL sensitivity is recognized. These dosimeters reveal similar glow curves as the standard TLD-100 (LiF:Mg,Ti) one irrespective of the use of modifiers and synthesis techniques. They display high sensitivity, low fading, dose response linearity over wide range and practical minimum detectable dose. Furthermore, the effective atomic number being the most beneficial aspect (equivalent to that of human tissue) of borate dosimeters do not show any change due to Cu ion activations. The past development, major challenges, excitement, applications, recent progress and the future promises of Cu doped borate TL dosimeters are highlighted. - Highlights: • The manuscript gives a panoramic overview on copper doped borate dosimeters. • Cu ions activated technique in borate

  5. Passive radon daughter dosimeters

    International Nuclear Information System (INIS)

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

    1986-03-01

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

  6. Dosimeter charging and/or reading apparatus

    International Nuclear Information System (INIS)

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

    1980-01-01

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

  7. The EPR in a few words: all you need to know about the EPR nuclear reactor

    International Nuclear Information System (INIS)

    2009-01-01

    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

  8. 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...

  9. Copper doped borate dosimeters revisited

    Energy Technology Data Exchange (ETDEWEB)

    Alajerami, Y.S.M. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Department of Medical Radiography, Al-Azhar University, Gaza Strip, Palestine (Country Unknown); Hashim, S., E-mail: suhairul@utm.my [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Oncology Treatment Centre, Sultan Ismail Hospital, 81100 Johor Bahru (Malaysia); Ghoshal, S.K. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Bradley, D.A. [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Mhareb, M. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Saleh, M.A. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); National Atomic Energy Commission (NATEC), Sana' a (Yemen)

    2014-11-15

    We render a panoramic overview on copper (Cu) doped borate dosimeters. Preparing a dosimeter by mixing specific materials with precise weights and methods is a never-ending quest. The recommended composition is highly decisive for accurate estimation of the absorbed dose, prediction of the biological outcome, determination of the treatment dose for radiation therapy and facilitation of personal monitoring. Based on these principles, the proposed dosimeter must cover a series of dosimetric properties to realize the exact results and assessment. The doped borate dosimeters indeed demonstrate attractive thermoluminescence (TL) features. Several dedicated efforts are attempted to improve the luminescence properties by doping various transition metals or rare-earth elements. The Cu ion being one of the preferred activators shows excellent TL properties as revealed via detail comparison with other dosimeters. Two oxide states of Cu (Cu{sup +} and Cu{sup ++}) with reasonable atomic number allow easy interaction with boron network. Interestingly, the intrinsic luminescent centers of borate lattice are in cross linked with that of Cu{sup +} ions. Thus, the activation of borate dosimeter with Cu ions for the enhancement of the TL sensitivity is recognized. These dosimeters reveal similar glow curves as the standard TLD-100 (LiF:Mg,Ti) one irrespective of the use of modifiers and synthesis techniques. They display high sensitivity, low fading, dose response linearity over wide range and practical minimum detectable dose. Furthermore, the effective atomic number being the most beneficial aspect (equivalent to that of human tissue) of borate dosimeters do not show any change due to Cu ion activations. The past development, major challenges, excitement, applications, recent progress and the future promises of Cu doped borate TL dosimeters are highlighted. - Highlights: • The manuscript gives a panoramic overview on copper doped borate dosimeters. • Cu ions activated

  10. Electronic dosimeter characteristics and new developments

    International Nuclear Information System (INIS)

    Thompson, I.M.G.

    1999-01-01

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

  11. Effect of the ionizing radiation on alanine solution for a dosimeter application

    International Nuclear Information System (INIS)

    Ketata, Ameni

    2011-01-01

    The electron spin resonance spectroscopy is well known as a reference and transfer dosimetry system for the evaluation of high doses in radiation processing. The high cost of an EPR/alanine dosimetry system is a serious handicap for large-scale routine application. In this study, the use of irradiated L-alanine dissolved in color indicator solutions (bromothymol blue and fuchsin) was investigated for dosimetry purposes. This solution has an absorbance varies linearly with the absorbed dose in the dose range of 0-25 kGy for the bromothymol blue, and 0-45 kGy for the fuchsin. The effects of the dye and the alanine concentration, the p H value as well as of the solvent have been studied. With respect to routine application, the stability of dosimeters was also investigated

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

    International Nuclear Information System (INIS)

    Galindo, S.; Urena-Nunez, F.

    1997-01-01

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

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

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  14. EPR by Areva. EPR the 1600+ MWe reactor

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    This brochure presents the GEN III+ EPR reactor designed by the Areva and Siemens consortium. The EPR reactor is a direct descendent of the well-proven N4 and KONVOI reactors, the most modern reactors in France and Germany. The EPR was designed by teams from KWU/Siemens and Framatome, EDF in France and the major German utilities, working in collaboration with both French and German safety authorities. The EPR integrates the results of decades of R and D programs, in particular those performed by the CEA (French Atomic Energy Commission) and the Karlsruhe Research Center in Germany. The EPR benefits from the experience of several thousand reactor-years of operation of pressurized water reactor technology. This experience has put 87 AREVA PWRs online throughout the world. Innovative Features: - An outer shell covering the reactor building, the spent fuel building and two of the four safeguard buildings provides protection against large commercial or military aircraft crash. - A heavy neutron reflector that surrounds the reactor core lowers uranium consumption. - An axial economizer inside the steam generator allows a high level of steam pressure and therefore high plant efficiency. - A core catcher allows passive collection and retention of the molten core should the reactor vessel fail in the highly unlikely event of a core melt. - A digital technology and a fully computerized control room with an operator friendly man-machine interface improve the reactor protection system.

  15. EPR by Areva. EPR the 1600+ MWe reactor

    International Nuclear Information System (INIS)

    2008-01-01

    This brochure presents the GEN III+ EPR reactor designed by the Areva and Siemens consortium. The EPR reactor is a direct descendent of the well-proven N4 and KONVOI reactors, the most modern reactors in France and Germany. The EPR was designed by teams from KWU/Siemens and Framatome, EDF in France and the major German utilities, working in collaboration with both French and German safety authorities. The EPR integrates the results of decades of R and D programs, in particular those performed by the CEA (French Atomic Energy Commission) and the Karlsruhe Research Center in Germany. The EPR benefits from the experience of several thousand reactor-years of operation of pressurized water reactor technology. This experience has put 87 AREVA PWRs online throughout the world. Innovative Features: - An outer shell covering the reactor building, the spent fuel building and two of the four safeguard buildings provides protection against large commercial or military aircraft crash. - A heavy neutron reflector that surrounds the reactor core lowers uranium consumption. - An axial economizer inside the steam generator allows a high level of steam pressure and therefore high plant efficiency. - A core catcher allows passive collection and retention of the molten core should the reactor vessel fail in the highly unlikely event of a core melt. - A digital technology and a fully computerized control room with an operator friendly man-machine interface improve the reactor protection system

  16. Kinetic study of UV-irradiated amorphous sulfur by EPR spectroscopy

    International Nuclear Information System (INIS)

    El Mkami, H.; Smith, G.M.

    2005-01-01

    Electron paramagnetic resonance (EPR) spectroscopy is used to investigate UV-irradiation damage in amorphous sulfur by examining post-irradiation kinetics as a function of UV-exposure time. The kinetic study is described by first-order concurrent reactions where the sulfur, as reactant, undergoes two parallel processes leading to the formation of two distinct defects called S 1 * and S 2 *. The temperature dependence of the EPR intensities of the signals, related to these defects, is used in the kinetic study

  17. Use of rapid-scan EPR to improve detection sensitivity for spin-trapped radicals.

    Science.gov (United States)

    Mitchell, Deborah G; Rosen, Gerald M; Tseitlin, Mark; Symmes, Breanna; Eaton, Sandra S; Eaton, Gareth R

    2013-07-16

    The short lifetime of superoxide and the low rates of formation expected in vivo make detection by standard continuous wave (CW) electron paramagnetic resonance (EPR) challenging. The new rapid-scan EPR method offers improved sensitivity for these types of samples. In rapid-scan EPR, the magnetic field is scanned through resonance in a time that is short relative to electron spin relaxation times, and data are processed to obtain the absorption spectrum. To validate the application of rapid-scan EPR to spin trapping, superoxide was generated by the reaction of xanthine oxidase and hypoxanthine with rates of 0.1-6.0 μM/min and trapped with 5-tert-butoxycarbonyl-5-methyl-1-pyrroline-N-oxide (BMPO). Spin trapping with BMPO to form the BMPO-OOH adduct converts the very short-lived superoxide radical into a more stable spin adduct. There is good agreement between the hyperfine splitting parameters obtained for BMPO-OOH by CW and rapid-scan EPR. For the same signal acquisition time, the signal/noise ratio is >40 times higher for rapid-scan than for CW EPR. Rapid-scan EPR can detect superoxide produced by Enterococcus faecalis at rates that are too low for detection by CW EPR. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  18. Heater design for reading radiation dosimeters

    International Nuclear Information System (INIS)

    Seidel, J.G.; Felice, P.E.

    1982-01-01

    The nichrome heating element of a conventional dosimeter reading apparatus has been redesigned to include a flat-bottomed depression big enough to hold a thermoluminescent dosimeter. A thin glass plate is positioned in the recess on top of the dosimeter to retain it in the recess during the heating and reading process. This technique of securing the dosimeter in contact with the heating element avoids physical scratching or damage to the dosimeter

  19. 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.

  20. Time-resolved EPR study of singlet oxygen in the gas phase.

    Science.gov (United States)

    Ruzzi, Marco; Sartori, Elena; Moscatelli, Alberto; Khudyakov, Igor V; Turro, Nicholas J

    2013-06-27

    X-band EPR spectra of singlet O2((1)Δg) and triplet O2((3)Σg(-)) were observed in the gas phase under low molecular-oxygen pressures PO2 = 0.175-0.625 Torr, T = 293-323 K. O2((1)Δg) was produced by quenching of photogenerated triplet sensitizers naphthalene C8H10, perdeuterated naphthalene, and perfluoronaphthalene in the gas phase. The EPR spectrum of O2((1)Δg) was also observed under microwave discharge. Integrated intensities and line widths of individual components of the EPR spectrum of O2((3)Σg(-)) were used as internal standards for estimating the concentration of O2 species and PO2 in the EPR cavity. Time-resolved (TR) EPR experiments of C8H10 were the main focus of this Article. Pulsed irradiation of C8H10 in the presence of O2((3)Σg(-)) allowed us to determine the kinetics of formation and decay for each of the four components of the O2((1)Δg) EPR signal, which lasted for only a few seconds. We found that the kinetics of EPR-component decay fit nicely to a biexponential kinetics law. The TR EPR 2D spectrum of the third component of the O2((1)Δg) EPR spectrum was examined in experiments using C8H10. This spectrum vividly presents the time evolution of an EPR component. The largest EPR signal and the longest lifetime of O2((1)Δg), τ = 0.4 s, were observed at medium pressure PO2 = 0.4 Torr, T = 293 K. The mechanism of O2((1)Δg) decay in the presence of photosensitizers is discussed. EPR spectra of O2((1)Δg) evidence that the spin-rotational states of O2((1)Δg) are populated according to Boltzmann distribution in the studied time range of 10-100 ms. We believe that this is the first report dealing with the dependence of O2((1)Δg) EPR line width on PO2 and T.

  1. How do monomeric components of a polymer gel dosimeter respond to ionising radiation: A steady-state radiolysis towards preparation of a 3D polymer gel dosimeter

    International Nuclear Information System (INIS)

    Kozicki, Marek

    2011-01-01

    Ionising radiation-induced reactions of aqueous single monomer solutions and mixtures of poly(ethylene glycol) diacrylate (PEGDA) and N,N'-methylenebisacrylamide (Bis) in a steady-state condition are presented below and above gelation doses in order to highlight reactions in irradiated 3D polymer gel dosimeters, which are assigned for radiotherapy dosimetry. Both monomers are shown to undergo radical polymerisation and cross-linking, which result in the measured increase in molecular weight and radius of gyration of the formed polydisperse polymer coils. The formation of nanogels was also observed for Bis solutions at a low concentration. In the case of PEGDA-Bis mixtures, co-polymerisation is suggested as well. At a sufficiently high radiation dose, the formation of a polymer network was observed for both monomers and their mixture. For this reason a sol-gel analysis for PEGDA and Bis was performed gravimetrically and a proposition of an alternative to this method employing a nuclear magnetic resonance technique is made. The two monomers were used for preparation of 3D polymer gel dosimeters having the acronyms PABIG and PABIG nx . The latter is presented for the first time in this work and is a type of the formerly established PABIG polymer gel dosimeter. The elementary characteristics of the new composition are presented, underlining the ease of its preparation, low dose threshold, and slightly increased sensitivity but lower quasi-linear range of dose response in comparison to PABIG. - Highlights: → Steady-state radiolysis of Bis, PEGDA and Bis-PEGDA is examined. → High Mw products are formed at low absorbed doses. → Formation of Bis nanogels is likely; PEGDA solutions form hydrogels. → NMR technique can be used for sol-gel analysis. → Features of 3D polymer gel dosimeters made from PEGDA and Bis are shown.

  2. 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

  3. Hanford personnel dosimeter supporting studies FY-1981

    International Nuclear Information System (INIS)

    1982-08-01

    This report examined specific functional components of the routine external personnel dosimeter program at Hanford. Components studied included: dosimeter readout; dosimeter calibration; dosimeter field response; dose calibration algorithm; dosimeter design; and TLD chip acceptance procedures. Additional information is also presented regarding the dosimeter response to light- and medium-filtered x-rays, high energy photons and neutrons. This study was conducted to clarify certain data obtained during the FY-1980 studies

  4. Radiation dosimeters for medical use

    International Nuclear Information System (INIS)

    Risticj, S. Goran

    2013-01-01

    The several personal radiation dosimeter types for medical use, which look like promising for this kind of application, as pMOS (RADFET) dosimeter, direct ion storage (DIS) dosimeters, thermoluminescent (TL) and optically stimulated luminescent (OSL) dosimeters, are described, and their advantages and disadvantages are analyzed. The p-channel metal-oxide-semiconductor (pMOS) dosimetric transistors allow dose measurements in vivo in real time, and they are especially important for radiotherapy. Direct ion storage (DIS) dosimeters are a hybrid of ion chamber and floating gate MOSFETs (FGMOSFETs), show very high sensitivity. Radiative processes that happen during the exposure of crystal to radiation are classified as prompt luminescence or radioluminescence (RL). In the case of an emission during stimulation, this phenomenon is referred to thermoluminescence or optically stimulated luminescence depending on whether the stimulation source is heat or light. TL and OSL dosimeters are natural or synthetic materials, which the intensity of emitted light is proportional to the irradiation dose. (Author)

  5. Characteristics of radiophotoluminescent glass dosimeters

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-07-01

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

  6. Monte Carlo simulation experiments on box-type radon dosimeter

    International Nuclear Information System (INIS)

    Jamil, Khalid; Kamran, Muhammad; Illahi, Ahsan; Manzoor, Shahid

    2014-01-01

    Epidemiological studies show that inhalation of radon gas ( 222 Rn) may be carcinogenic especially to mine workers, people living in closed indoor energy conserved environments and underground dwellers. It is, therefore, of paramount importance to measure the 222 Rn concentrations (Bq/m 3 ) in indoors environments. For this purpose, box-type passive radon dosimeters employing ion track detector like CR-39 are widely used. Fraction of the number of radon alphas emitted in the volume of the box type dosimeter resulting in latent track formation on CR-39 is the latent track registration efficiency. Latent track registration efficiency is ultimately required to evaluate the radon concentration which consequently determines the effective dose and the radiological hazards. In this research, Monte Carlo simulation experiments were carried out to study the alpha latent track registration efficiency for box type radon dosimeter as a function of dosimeter’s dimensions and range of alpha particles in air. Two different self developed Monte Carlo simulation techniques were employed namely: (a) Surface ratio (SURA) method and (b) Ray hitting (RAHI) method. Monte Carlo simulation experiments revealed that there are two types of efficiencies i.e. intrinsic efficiency (η int ) and alpha hit efficiency (η hit ). The η int depends upon only on the dimensions of the dosimeter and η hit depends both upon dimensions of the dosimeter and range of the alpha particles. The total latent track registration efficiency is the product of both intrinsic and hit efficiencies. It has been concluded that if diagonal length of box type dosimeter is kept smaller than the range of alpha particle then hit efficiency is achieved as 100%. Nevertheless the intrinsic efficiency keeps playing its role. The Monte Carlo simulation experimental results have been found helpful to understand the intricate track registration mechanisms in the box type dosimeter. This paper explains that how radon

  7. Monte Carlo simulation experiments on box-type radon dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Jamil, Khalid, E-mail: kjamil@comsats.edu.pk; Kamran, Muhammad; Illahi, Ahsan; Manzoor, Shahid

    2014-11-11

    Epidemiological studies show that inhalation of radon gas ({sup 222}Rn) may be carcinogenic especially to mine workers, people living in closed indoor energy conserved environments and underground dwellers. It is, therefore, of paramount importance to measure the {sup 222}Rn concentrations (Bq/m{sup 3}) in indoors environments. For this purpose, box-type passive radon dosimeters employing ion track detector like CR-39 are widely used. Fraction of the number of radon alphas emitted in the volume of the box type dosimeter resulting in latent track formation on CR-39 is the latent track registration efficiency. Latent track registration efficiency is ultimately required to evaluate the radon concentration which consequently determines the effective dose and the radiological hazards. In this research, Monte Carlo simulation experiments were carried out to study the alpha latent track registration efficiency for box type radon dosimeter as a function of dosimeter’s dimensions and range of alpha particles in air. Two different self developed Monte Carlo simulation techniques were employed namely: (a) Surface ratio (SURA) method and (b) Ray hitting (RAHI) method. Monte Carlo simulation experiments revealed that there are two types of efficiencies i.e. intrinsic efficiency (η{sub int}) and alpha hit efficiency (η{sub hit}). The η{sub int} depends upon only on the dimensions of the dosimeter and η{sub hit} depends both upon dimensions of the dosimeter and range of the alpha particles. The total latent track registration efficiency is the product of both intrinsic and hit efficiencies. It has been concluded that if diagonal length of box type dosimeter is kept smaller than the range of alpha particle then hit efficiency is achieved as 100%. Nevertheless the intrinsic efficiency keeps playing its role. The Monte Carlo simulation experimental results have been found helpful to understand the intricate track registration mechanisms in the box type dosimeter. This paper

  8. EPR: Evidence and fallacy.

    Science.gov (United States)

    Nichols, Joseph W; Bae, You Han

    2014-09-28

    The enhanced permeability and retention (EPR) of nanoparticles in tumors has long stood as one of the fundamental principles of cancer drug delivery, holding the promise of safe, simple and effective therapy. By allowing particles preferential access to tumors by virtue of size and longevity in circulation, EPR provided a neat rationale for the trend toward nano-sized drug carriers. Following the discovery of the phenomenon by Maeda in the mid-1980s, this rationale appeared to be well justified by the flood of evidence from preclinical studies and by the clinical success of Doxil. Clinical outcomes from nano-sized drug delivery systems, however, have indicated that EPR is not as reliable as previously thought. Drug carriers generally fail to provide superior efficacy to free drug systems when tested in clinical trials. A closer look reveals that EPR-dependent drug delivery is complicated by high tumor interstitial fluid pressure (IFP), irregular vascular distribution, and poor blood flow inside tumors. Furthermore, the animal tumor models used to study EPR differ from clinical tumors in several key aspects that seem to make EPR more pronounced than in human patients. On the basis of this evidence, we believe that EPR should only be invoked on a case-by-case basis, when clinical evidence suggests the tumor type is susceptible. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Electron paramagnetic resonance (EPR) biodosimetry

    International Nuclear Information System (INIS)

    Desrosiers, Marc; Schauer, David A.

    2001-01-01

    Radiation-induced electron paramagnetic resonance (EPR) signals were first reported by Gordy et al. [Proc. Natl. Acad. Sci. USA 41 (1955) 983]. The application of EPR spectroscopy to ionizing radiation dosimetry was later proposed by Brady et al. [Health Phys. 15 (1968) 43]. Since that time EPR dosimetry has been applied to accident and epidemiologic dose reconstruction, radiation therapy, food irradiation, quality assurance programs and archaeological dating. Materials that have been studied include bone, tooth enamel, alanine and quartz. This review paper presents the fundamentals and applications of EPR biodosimetry. Detailed information regarding sample collection and preparation, EPR measurements, dose reconstruction, and data analysis and interpretation will be reviewed for tooth enamel. Examples of EPR biodosimetry application in accidental overexposures, radiopharmaceutical dose assessment and retrospective epidemiologic studies will also be presented

  10. Boron dose determination for BNCT using Fricke and EPR dosimetry

    International Nuclear Information System (INIS)

    Wielopolski, L.; Ciesielski, B.

    1995-01-01

    In Boron Neutron Capture Therapy (BNCT) the dominant dose delivered to the tumor is due to α and 7 Li charged particles resulting from a neutron capture by 10 B and is referred to herein as the boron dose. Boron dose is directly attributable to the following two independent factors, one boron concentration and the neutron capture energy dependent cross section of boron, and two the energy spectrum of the neutrons that interact with boron. The neutron energy distribution at a given point is dictated by the incident neutron energy distribution, the depth in tissue, geometrical factors such as beam size and patient's dimensions. To account for these factors can be accommodated by using Monte Carlo theoretical simulations. However, in conventional experimental BNCT dosimetry, e.g., using TLDs or ionization chambers, it is only possible to estimate the boron dose. To overcome some of the limitations in the conventional dosimetry, modifications in ferrous sulfate dosimetry (Fricke) and Electron Paramagnetic Resonance (EPR) dosimetry in alanine, enable to measure specifically boron dose in a mixed gamma neutron radiation fields. The boron dose, in either of the dosimeters, is obtained as a difference between measurements with boronated and unboronated dosimeters. Since boron participates directly in the measurements, the boron dosimetry reflects the true contribution, integral of the neutron energy spectrum with boron cross section, of the boron dose to the total dose. Both methods are well established and used extensively in dosimetry, they are presented briefly here

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

    International Nuclear Information System (INIS)

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

    2015-10-01

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

  12. Fast-neutron solid-state dosimeter

    International Nuclear Information System (INIS)

    Kecker, K.H.; Haywood, F.F.; Perdue, P.T.; Thorngate, J.H.

    1975-01-01

    This patent relates to an improved fast-neutron solid-state dosimeter that does not require separation of materials before it can be read out, that utilizes materials that do not melt or otherwise degrade at about 300 0 C readout temperature, that provides a more efficient dosimeter, and that can be reused. The dosimeters are fabricated by intimately mixing a TL material, such as CaSO 4 :Dy, with a powdered polyphenyl, such as p-sexiphenyl, and hot-pressing the mixture to form pellets, followed by out-gassing in a vacuum furnace at 150 0 C prior to first use dosimeters

  13. Evaluation of discrepancies between thermoluminescent dosimeter and direct-reading dosimeter results

    International Nuclear Information System (INIS)

    Shaw, K.R.

    1993-07-01

    Currently at Oak Ridge National Laboratory (ORNL), the responses of thermoluminescent dosimeters (TLDs) and direct-reading dosimeters (DRDs) are not officially compared or the discrepancies investigated. However, both may soon be required due to the new US Department of Energy (DOE) Radiological Control Manual. In the past, unofficial comparisons of the two dosimeters have led to discrepancies of up to 200%. This work was conducted to determine the reasons behind such discrepancies. For tests conducted with the TLDs, the reported dose was most often lower than the delivered dose, while DRDs most often responded higher than the delivered dose. Trends were identified in personnel DRD readings, and ft was concluded that more training and more control of the DRDs could improve their response. TLD responses have already begun to be improved; a new background subtraction method was implemented in April 1993, and a new dose algorithm is being considered. It was concluded that the DOE Radiological Control Manual requirements are reasonable for identifying discrepancies between dosimeter types, and more stringent administrative limits might even be considered

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

    Science.gov (United States)

    Nakagawa, Kouichi; Epel, Boris

    2014-10-15

    In this study, noninvasive 9GHz 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 9GHz EPR imaging capabilities. The 9GHz EPR-imager easily resolved the LiPC samples at a distance of ∼2mm. Then, commercially available black pepper seeds were measured. We observed signatures from three different radical species, which were assigned to stable organic radicals, Fe(3+), and Mn(2+) complexes. In addition, no EPR spectral change in the seed was observed after it was submerged in distilled H2O for 1h. 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 9GHz EPR imaging were useful for the determination of the spatial distribution of paramagnetic species in various seeds. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Homogeneity and EPR metrics for assessment of regular grids used in CW EPR powder simulations.

    Science.gov (United States)

    Crăciun, Cora

    2014-08-01

    CW EPR powder spectra may be approximated numerically using a spherical grid and a Voronoi tessellation-based cubature. For a given spin system, the quality of simulated EPR spectra depends on the grid type, size, and orientation in the molecular frame. In previous work, the grids used in CW EPR powder simulations have been compared mainly from geometric perspective. However, some grids with similar homogeneity degree generate different quality simulated spectra. This paper evaluates the grids from EPR perspective, by defining two metrics depending on the spin system characteristics and the grid Voronoi tessellation. The first metric determines if the grid points are EPR-centred in their Voronoi cells, based on the resonance magnetic field variations inside these cells. The second metric verifies if the adjacent Voronoi cells of the tessellation are EPR-overlapping, by computing the common range of their resonance magnetic field intervals. Beside a series of well known regular grids, the paper investigates a modified ZCW grid and a Fibonacci spherical code, which are new in the context of EPR simulations. For the investigated grids, the EPR metrics bring more information than the homogeneity quantities and are better related to the grids' EPR behaviour, for different spin system symmetries. The metrics' efficiency and limits are finally verified for grids generated from the initial ones, by using the original or magnetic field-constraint variants of the Spherical Centroidal Voronoi Tessellation method. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Homogeneity and EPR metrics for assessment of regular grids used in CW EPR powder simulations

    Science.gov (United States)

    Crăciun, Cora

    2014-08-01

    CW EPR powder spectra may be approximated numerically using a spherical grid and a Voronoi tessellation-based cubature. For a given spin system, the quality of simulated EPR spectra depends on the grid type, size, and orientation in the molecular frame. In previous work, the grids used in CW EPR powder simulations have been compared mainly from geometric perspective. However, some grids with similar homogeneity degree generate different quality simulated spectra. This paper evaluates the grids from EPR perspective, by defining two metrics depending on the spin system characteristics and the grid Voronoi tessellation. The first metric determines if the grid points are EPR-centred in their Voronoi cells, based on the resonance magnetic field variations inside these cells. The second metric verifies if the adjacent Voronoi cells of the tessellation are EPR-overlapping, by computing the common range of their resonance magnetic field intervals. Beside a series of well known regular grids, the paper investigates a modified ZCW grid and a Fibonacci spherical code, which are new in the context of EPR simulations. For the investigated grids, the EPR metrics bring more information than the homogeneity quantities and are better related to the grids’ EPR behaviour, for different spin system symmetries. The metrics’ efficiency and limits are finally verified for grids generated from the initial ones, by using the original or magnetic field-constraint variants of the Spherical Centroidal Voronoi Tessellation method.

  17. Operation of Personal Electronic Dosimeters at NRCN

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  18. Chemistry of artemisinin: an EPR study and nucleobases interaction

    International Nuclear Information System (INIS)

    Mustafa, Damra Elhaj

    2000-10-01

    In the present, the radical transformations of artemisinin, a potent antimalarial drug have been examined using EPR and EPR spin trapping techniques. The effect of light on artemisinin has been investigated at 77 K as well as with the use of phenyl butyl nitrone (PBN) spin trapping agent. While no EPR signal was observed at 77 K, intense light irradiation of artemisinin/PBN gave EPR signal characteristic of radical transformation of the PBN. The reactions of artemisinin with iron (II), manganese (II), hemin and ferrocyanide ion have been investigated by spin trapping techniques. Artemisinin/iron (II) formed spin adducts with nitrosobenzene, nitroso-t-butane and PBN. The hypertine splittings of the spin adducts were a N =1.08 mT/a N =1.25 mT/a N =0.09 mT and a N =1.56 mT/a N =0.29 mT respectively. PBN trapping of artemether/iron (II) gave similar result to artemisinin/iron (II). These results are indicative of secondary carbon-centered radical formation. While artemisinin/hemin/PBN gave very weak EPR signal, ferrocyanide under the same condition gave no signal. Incubation of artemisinin with RNA at different reaction conditions, including irradiation with light, heat and mild acidic media, revealed no RNA damage when examined by agarose electrophoresis. However, artemisinin/iron (II) caused RNA damage in pH-dependant manner. In contrast, hemin did not show the same effect when it was used instead of iron (II). (Author)

  19. To the attention of all dosimeter users

    CERN Multimedia

    2005-01-01

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

  20. To the attention of all dosimeter users

    CERN Multimedia

    Dosimetry Service

    2005-01-01

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

  1. To the attention of all dosimeter users

    CERN Multimedia

    Dosimetry Service

    2006-01-01

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

  2. Thermoluminescent dosimeter system

    International Nuclear Information System (INIS)

    Felice, P.E.; Gonzalez, J.L.; Seidel, J.G.

    1979-01-01

    An improved thermoluminescent dosimeter system and apparatus for sensing alpha particle emission is described. A thermoluminescent body is sealed between a pair of metallized plastic films. The dosimeter is mounted within a protective inverted cup or a tube closed at one end, which is disposed in a test hole for exposure to radioactive radon gas which is indicaive of uranium deposits

  3. Cell-phone interference with pocket dosimeters

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  4. Cell-phone interference with pocket dosimeters

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-05-07

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

  5. Flame-sintered ceramic exoelectron dosimeter samples

    International Nuclear Information System (INIS)

    Petel, M.; Holzapfel, G.

    1979-01-01

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

  6. Age-related peculiarities of tooth enamel as a natural EPR biodosimeter

    International Nuclear Information System (INIS)

    Sholom, S.; Chumak, V.

    2008-01-01

    The influence of age on tooth enamel as an EPR dosimeter has been investigated using a big collection of teeth extracted from several tens of persons living in different regions of Ukraine. The study was focused on two groups of teeth. The first one represented the urban population while the second corresponded to residents of rural settlements. Age dependences of two above groups were quite different: for example, doses for the 65-75 year age group were approximately 200 mGy higher for urban population compared to habitants of rural settlements. This effect was explained by contribution of medical X-ray exposure: the comparison of corresponding lingual and buccal doses revealed the more frequent presence of X-ray dose for urban population. Another observed effect was the difference between average intensities of native signals for two studied groups. At present time, no correlation with age was seen for this effect

  7. Passive dosimeters other than film and TLDs [thermoluminescent dosimeter

    International Nuclear Information System (INIS)

    Hankins, D.E.

    1986-01-01

    This presentation will describe CR-39 plastic as a personnel neutron dosimeter. Recent research at LLNL and elsewhere has resulted in the development of a dosimetry system that is superior to any personnel neutron dosimeter previously available. The author describes the features of the dosimetry system and the new etching procedures and techniques in detail. Most of the research was done at the LLNL and has been supported as a part of the DOE Neutron Dosimetry Upgrade Program. 10 refs., 4 figs., 1 tab

  8. Neutron dosimeter

    International Nuclear Information System (INIS)

    Bartko, J.; Schoch, K.F. Jr.; Congedo, T.V.; Anderson, S.L. Jr.

    1989-01-01

    This patent describes a nuclear reactor. It comprises a reactor core; a thermal shield surrounding the reactor core; a pressure vessel surrounding the thermal shield; a neutron dosimeter positioned outside of the thermal shield, the neutron dosimeter comprising a layer of fissile material and a second layer made of a material having an electrical conductivity which permanently varies as a function of its cumulative ion radiation dose; and means, outside the pressure vessel and electrically connected to the layer of second material, for measuring electrical conductivity of the layer of second material

  9. EPR-based material modelling of soils

    Science.gov (United States)

    Faramarzi, Asaad; Alani, Amir M.

    2013-04-01

    In the past few decades, as a result of the rapid developments in computational software and hardware, alternative computer aided pattern recognition approaches have been introduced to modelling many engineering problems, including constitutive modelling of materials. The main idea behind pattern recognition systems is that they learn adaptively from experience and extract various discriminants, each appropriate for its purpose. In this work an approach is presented for developing material models for soils based on evolutionary polynomial regression (EPR). EPR is a recently developed hybrid data mining technique that searches for structured mathematical equations (representing the behaviour of a system) using genetic algorithm and the least squares method. Stress-strain data from triaxial tests are used to train and develop EPR-based material models for soil. The developed models are compared with some of the well-known conventional material models and it is shown that EPR-based models can provide a better prediction for the behaviour of soils. The main benefits of using EPR-based material models are that it provides a unified approach to constitutive modelling of all materials (i.e., all aspects of material behaviour can be implemented within a unified environment of an EPR model); it does not require any arbitrary choice of constitutive (mathematical) models. In EPR-based material models there are no material parameters to be identified. As the model is trained directly from experimental data therefore, EPR-based material models are the shortest route from experimental research (data) to numerical modelling. Another advantage of EPR-based constitutive model is that as more experimental data become available, the quality of the EPR prediction can be improved by learning from the additional data, and therefore, the EPR model can become more effective and robust. The developed EPR-based material models can be incorporated in finite element (FE) analysis.

  10. Molecular structure effects on the post irradiation diffusion in polymer gel dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Mattea, F.; Romero, M.; Strumia, M. [Instituto Multidisciplinario de Biologia Vegetal / CONICET, Universidad Nacional de Cordoba, Departamento de Quimica Organica, Ciudad Universitaria, 5000 Cordoba (Argentina); Vedelago, J. [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); Quiroga, A. [Centro de Investigacion y Estudios de Matematica / CONICET, Oficina 318 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina); Valente, M., E-mail: fmattea@gmail.com [Instituto de Fisica E. Gaviola / CONICET, LIIFAMIRx, Oficina 102 FaMAF - UNC, 5000 Cordoba (Argentina)

    2014-08-15

    Polymer gel dosimeters have specific advantages for recording 3D radiation dose distribution representing a key factor for most of the therapeutic and diagnostic radiation techniques. Radiation-induced polymerization and crosslinking reactions that take place in the dosimeter have been studied for different monomers like acrylamide and N,N-methylene-bis acrylamide (Bis) and most recently for less toxic monomers like N-isopropylacrylamide and Bis. In this work a novel system based on itaconic acid and Bis is proposed, the radical polymerization or gel formation of these monomers has been already studied for the formation of an hydrogel for non dosimetric applications and their reactivity are comparable with the already mentioned systems. Although the 3D structure is maintained after the dosimeter has been irradiated, it is not possible to eliminate the diffusion of the reacted and monomer species in regions of dose gradients within the gel after irradiation. As a consequence the dose information of the dosimeters loose quality over time. The mobility within the gelatin structure of the already mentioned species is related to their chemical structure, and nature. In this work the effect of changes in the chemical structure of the monomers over the dosimetric sensitivity and over the post-irradiation diffusion of species is studied. One of the acrylic acid groups of the itaconic acid molecule is modified to obtain molecules with similar reactivity but different molecular sizes. Dosimetric systems with these modified species, Bis, an antioxidant to avoid oxygen polymerization inhibition, water and gelatin are irradiated in an X-ray tomography at different doses, and the resulting dosimeters are characterized by Raman spectroscopy and optical absorbance to study their feasibility and capabilities as dosimetric systems, and by optical-CT to analyze the diffusion degree after being irradiated. (Author)

  11. Molecular structure effects on the post irradiation diffusion in polymer gel dosimeters

    International Nuclear Information System (INIS)

    Mattea, F.; Romero, M.; Strumia, M.; Vedelago, J.; Quiroga, A.; Valente, M.

    2014-08-01

    Polymer gel dosimeters have specific advantages for recording 3D radiation dose distribution representing a key factor for most of the therapeutic and diagnostic radiation techniques. Radiation-induced polymerization and crosslinking reactions that take place in the dosimeter have been studied for different monomers like acrylamide and N,N-methylene-bis acrylamide (Bis) and most recently for less toxic monomers like N-isopropylacrylamide and Bis. In this work a novel system based on itaconic acid and Bis is proposed, the radical polymerization or gel formation of these monomers has been already studied for the formation of an hydrogel for non dosimetric applications and their reactivity are comparable with the already mentioned systems. Although the 3D structure is maintained after the dosimeter has been irradiated, it is not possible to eliminate the diffusion of the reacted and monomer species in regions of dose gradients within the gel after irradiation. As a consequence the dose information of the dosimeters loose quality over time. The mobility within the gelatin structure of the already mentioned species is related to their chemical structure, and nature. In this work the effect of changes in the chemical structure of the monomers over the dosimetric sensitivity and over the post-irradiation diffusion of species is studied. One of the acrylic acid groups of the itaconic acid molecule is modified to obtain molecules with similar reactivity but different molecular sizes. Dosimetric systems with these modified species, Bis, an antioxidant to avoid oxygen polymerization inhibition, water and gelatin are irradiated in an X-ray tomography at different doses, and the resulting dosimeters are characterized by Raman spectroscopy and optical absorbance to study their feasibility and capabilities as dosimetric systems, and by optical-CT to analyze the diffusion degree after being irradiated. (Author)

  12. A new radiochromic dosimeter film

    Science.gov (United States)

    Sidney, L. N.; Lynch, D. C.; Willet, P. S.

    By employing acid-sensitive leuco dyes in a chlorine-containing polymer matrix, a new radiochromic dosimeter film has been developed for gamma, electron beam, and ultraviolet radiation. These dosimeter films undergo a color change from colorless to royal blue, red fuchsia, or black, depending on dye selection, and have been characterized using a visible spectrophotometer over an absorbed dose range of 1 to 100 kGy. The primary features of the film are improved color stability before and after irradiation, whether stored in the dark or under artificial lights, and improved moisture resistance. The effects of absorbed dose, dose rate, and storage conditions on dosimeter performance are discussed. The dosimeter material may be produced as a free film or coated onto a transparent substrate and optionally backed with adhesive. Potential applications for these materials include gamma sterilization indicator films for food and medical products, electron beam dosimeters, and in-line radiation monitors for electron beam and ultraviolet processing.

  13. Determination of dose enhancement caused by gold-nanoparticles irradiated with proton, X-rays (kV and MV) and electron beams, using alanine/EPR dosimeters

    International Nuclear Information System (INIS)

    Smith, Clare L.; Ackerly, Trevor; Best, Stephen P.; Gagliardi, Frank; Kie, Katahira; Little, Peter J.; McCorkell, Giulia; Sale, Charlotte A.; Tsunei, Yusuke; Tominaga, Takahiro; Volaric, Sioe See; Geso, Moshi

    2015-01-01

    The main aims of this research was to employ alanine doped with gold-nanoparticles “AuNPs” to determine the levels of dose enhancement caused by these particles when irradiated with proton beams, low and high energy X-rays and electrons. DL-alanine was impregnated with 5 nm gold-nanoparticles (3% by weight) and added as a uniform layer within a wax pellet of dimensions 10 × 5 × 5 mm. Control pellets, containing DL-Alanine were also produced, and placed within a phantom, and exposed to various types of radiations: low energy (kV ranges) X-rays were obtained from a superficial machine, high energy (MV) X-rays and electrons derived from a linear accelerator, and protons were produced by the Hyogo Ion Beam Centre in Japan. Nominal doses received ranged from 2 to 20 Gy (within clinical range). The Electron Paramagnetic Resonance (EPR) spectra of the irradiated samples were recorded on a BRUKER Elexsys 9.5 MHz. The dose enhancement caused by gold nanoparticles for 80 kV x-rays was found to be more than 60% at about 5 Gy. Smaller dose enhancements (under the same measurement conditions) were observed for megavoltage x-ray beams (up to 10%). Dose enhancement caused by charged particles indicated minimal values for 6 MeV electrons (approximately 5%) whilst less than that is obtained with protons of 150 MeV. The proton results validate the latest simulation results based on Monte Carlo calculations but the dose enhancement is significantly less than that reported in cell and animal model systems, (about 20%). We attribute this difference to the fact that alanine only measures the levels of free radicals generated by the inclusion of nanoparticles and not the redox type radicals (such as reactive oxygen species) generated from aqueous media in cells. Dose enhancement caused by 5 nm gold-nanoparticles with radiotherapy type proton beams has been found to be less than 5% as determined when using alanine/wax as both a phantom and dosimeter. This agrees well

  14. Evaluation of personal dosimeters

    International Nuclear Information System (INIS)

    Correa, C. A.

    2007-01-01

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

  15. Improved sample holders for the PMMA dosimeters

    International Nuclear Information System (INIS)

    Kobayashi, Toshikazu; Sone, Koji; Iso, Katsuaki

    1994-01-01

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

  16. 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.

  17. The intelligence of dosimeter for ionization radiation

    International Nuclear Information System (INIS)

    He Jinglun

    1992-01-01

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

  18. 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.

  19. Citizen's dosimeter

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-09-02

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

  20. Chemistry of artemisinin: an EPR study and nucleobases interaction

    Energy Technology Data Exchange (ETDEWEB)

    Mustafa, Damra Elhaj [Department of Chemistry, Faculty of Education, University of Khartoum, Khartoum (Sudan)

    2000-10-01

    In the present, the radical transformations of artemisinin, a potent antimalarial drug have been examined using EPR and EPR spin trapping techniques. The effect of light on artemisinin has been investigated at 77 K as well as with the use of phenyl butyl nitrone (PBN) spin trapping agent. While no EPR signal was observed at 77 K, intense light irradiation of artemisinin/PBN gave EPR signal characteristic of radical transformation of the PBN. The reactions of artemisinin with iron (II), manganese (II), hemin and ferrocyanide ion have been investigated by spin trapping techniques. Artemisinin/iron (II) formed spin adducts with nitrosobenzene, nitroso-t-butane and PBN. The hypertine splittings of the spin adducts were a{sub N}=1.08 mT/a{sub N}=1.25 mT/a{sub N}=0.09 mT and a{sub N}=1.56 mT/a{sub N}=0.29 mT respectively. PBN trapping of artemether/iron (II) gave similar result to artemisinin/iron (II). These results are indicative of secondary carbon-centered radical formation. While artemisinin/hemin/PBN gave very weak EPR signal, ferrocyanide under the same condition gave no signal. Incubation of artemisinin with RNA at different reaction conditions, including irradiation with light, heat and mild acidic media, revealed no RNA damage when examined by agarose electrophoresis. However, artemisinin/iron (II) caused RNA damage in pH-dependant manner. In contrast, hemin did not show the same effect when it was used instead of iron (II). (Author)

  1. Acoustic evaluation of polymer gel dosimeters

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  2. 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.

  3. SDI-100 radiation dosimeter

    International Nuclear Information System (INIS)

    Zheng Zheng; Zhao Yongfu; Dai Honggui

    1995-01-01

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

  4. EPR persistence measurements of UV-induced melanin free radicals in whole skin

    International Nuclear Information System (INIS)

    Collins, B.; Poehler, T.O.; Bryden, W.A.

    1995-01-01

    Electron paramagnetic resonance is used to detect the formation of free radicals caused by exposure to ultraviolet radiation in chemically untreated rabbit skin. A fast jump in EPR signal level, occurring over a few seconds, is observed immediately after a skin sample is exposed to UV. This is followed by a slower increase toward an elevated steady-state signal over a period of hours as the skin is continuously exposed to a UV light source. Upon cessation of UV light exposure, EPR signal levels undergo an abrupt drop followed by a slower decay toward natural levels. Elevated free radical concentrations following UV exposure are found to persist for several hours in whole skin. These results are consistent with time resolved EPR measurements of photoinduced radicals in various natural melanins. (Author)

  5. 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.)

  6. Towards EPR (European pressurized reactor)

    International Nuclear Information System (INIS)

    Anon.

    2003-01-01

    According to the French industry minister, it is nonsense continuing delaying the construction of an EPR prototype because France needs it in order to renew timely its park of nuclear reactors. The renewing is expected to begin in 2020 and will be assured with third generation reactors like EPR. A quick launching of the EPR prototype is necessary to have it being in service by 2012, the feedback operating experience that will be accumulated over the 8 years that will follow will be necessary to optimize the industrial version and to have it ready by 2020. The EPR reactor has indisputable assets: modern, safer, more competitive and it will produce less wastes than present nuclear reactors. The construction cost of an EPR prototype is estimated to 3 milliard Euros and the nuclear industry operators propose to finance it completely. The EPR prototype does not jeopardize the ambitious French program about renewable energy sources, France is committed to produce 21% of its electricity from renewable energies by 2010 and 10 milliard Euros will be invested over this period on wind energy. Nuclear energy and alternative energies must be considered as 2 aspects of a diversified energy policy. (A.C.)

  7. Radon daughter dosimeter

    International Nuclear Information System (INIS)

    Durkin, J.

    1977-01-01

    This patent describes a portable radon daughter dosimeter unit used to measure radon gas alpha daughters in ambient air. These measurements can then be related to preselected preestablished standards contained in a remote central readout unit. The dosimeter unit is adapted to be worn by an operator in areas having alpha particle radiation such as in uranium mines. Within the dosimeter is a detector head housing having a filter head and a solid state surface barrier radiation detector; an air pump to get air to the detector head; a self contained portable power supply for the unit; and electronic circuitry to process detected charged electrons from the detector head to convert and count their pulses representatives of two alpha radon emitter daughters. These counted pulses are in binary form and are sent to a readout unit where a numerical readout displays the result in terms of working level-hours

  8. Radon daughter dosimeter

    International Nuclear Information System (INIS)

    Durkin, J.

    1977-01-01

    A portable radon daughter dosimeter unit used to measure Radon gas alpha daughters in ambient air is described. These measurements can then be related to preselected preestablished standards contained in a remote central readout unit. The dosimeter unit is adapted to be worn by an operator in areas having alpha particle radiation such as uranium mines. Within the dosimeter is a detector head housing having a filter head and a solid state surface barrier radiation detector; an air pump to get air to the detector head; a self contained portable power supply for the unit; and electronic circuitry to process detected charged electrons from the detector head to convert and count their pulses representatives of two alpha radon emitter daughters. These counted pulses are in binary form and are sent to a readout unit where a numerical readout diplays the result in terms of working level-hours

  9. Hanford beta-gamma personnel dosimeter prototypes and evaluation

    International Nuclear Information System (INIS)

    Fix, J.J.; Holbrook, K.L.; Soldat, K.L.

    1983-04-01

    Upgraded and modified Hanford dosimeter prototypes were evaluated for possible use at Hanford as a primary beta-gamma dosimeter. All prototypes were compatible with the current dosimeter card and holder design, as well as processing with the automated Hanford readers. Shallow- and deep-dose response was determined for selected prototypes using several beta sources, K-fluorescent x rays and filtered x-ray techniques. All prototypes included a neutron sensitive chip. A progressive evaluation of the performance of each of the upgrades to the current dosimeter is described. In general, the performance of the current dosimeter can be upgraded using individual chip sensitivity factors to improve precision and an improved algorithm to minimize bias. The performance of this dosimeter would be adequate to pass all categories of the ANSI N13.11 performance criteria for dosimeter procesors, provided calibration techniques compatible with irradiations adopted in the standard were conducted. The existing neutron capability of the dosimeter could be retained. Better dosimeter performance to beta-gamma radiation can be achieved by modifying the Hanford dosimeter so that four of the five chip positions are devoted to calculating these doses instead of the currently used two chip positions. A neutron sensitive chip was used in the 5th chip position, but all modified dosimeter prototypes would be incapable of discriminating between thermal and epithermal neutrons. An improved low energy beta response can be achieved for the current dosimeter and all prototypes considered by eliminating the security credential. Further improvement can be obtained by incorporating the 15-mil thick TLD-700 chips

  10. Probing Microenvironment in Ionic Liquids by Time-Resolved EPR of Photoexcited Triplets.

    Science.gov (United States)

    Ivanov, M Yu; Veber, S L; Prikhod'ko, S A; Adonin, N Yu; Bagryanskaya, E G; Fedin, M V

    2015-10-22

    Unusual physicochemical properties of ionic liquids (ILs) open vistas for a variety of new applications. Herewith, we investigate the influence of microviscosity and nanostructuring of ILs on spin dynamics of the dissolved photoexcited molecules. We use two most common ILs [Bmim]PF6 and [Bmim]BF4 (with its close analogue [C10mim]BF4) as solvents and photoexcited Zn tetraphenylporphyrin (ZnTPP) as a probe. Time-resolved electron paramagnetic resonance (TR EPR) is employed to investigate spectra and kinetics of spin-polarized triplet ZnTPP in the temperature range 100-270 K. TR EPR data clearly indicate the presence of two microenvironments of ZnTPP in frozen ILs at 100-200 K, being manifested in different spectral shapes and different spin relaxation rates. For one of these microenvironments TR EPR data is quite similar to those obtained in common frozen organic solvents (toluene, glycerol, N-methyl-2-pyrrolidone). However, the second one favors the remarkably slow relaxation of spin polarization, being much longer than in the case of common solvents. Additional experiments using continuous wave EPR and stable nitroxide as a probe confirmed the formation of heterogeneities upon freezing of ILs and complemented TR EPR results. Thus, TR EPR of photoexcited triplets can be effectively used for probing heterogeneities and nanostructuring in frozen ILs. In addition, the increase of polarization lifetime in frozen ILs is an interesting finding that might allow investigation of short-lived intermediates inaccessible otherwise.

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

    International Nuclear Information System (INIS)

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

    1976-04-01

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

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

    OpenAIRE

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

    2017-01-01

    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 ca...

  13. Silver nitrate based gel dosimeter

    International Nuclear Information System (INIS)

    Titus, D; Samuel, E J J; Srinivasan, K; Roopan, S M; Madhu, C S

    2017-01-01

    A new radiochromic gel dosimeter based on silver nitrate and a normoxic gel dosimeter was investigated using UV-Visible spectrophotometry in the clinical dose range. Gamma radiation induced the synthesis of silver nanoparticles in the gel and is confirmed from the UV-Visible spectrum which shows an absorbance peak at around 450 nm. The dose response function of the dosimeter is found to be linear upto12Gy. In addition, the gel samples were found to be stable which were kept under refrigeration. (paper)

  14. Medical application of EPR

    International Nuclear Information System (INIS)

    Eichhoff, Uwe; Hoefer, Peter

    2015-01-01

    Selected applications of continuous-wave EPR in medicine are reviewed. This includes detection of reactive oxygen and nitrogen species, pH measurements and oxymetry. Applications of EPR imaging are demonstrated on selected examples and future developments to faster imaging methods are discussed

  15. EPR compared to international requirements (Mainly EUR)

    International Nuclear Information System (INIS)

    Broecker, B.

    1996-01-01

    A number of European Utilities have entered an agreement to write common requirements dedicated to future light water nuclear power plants to be built in Europe. The activities are known under the sign EUR (European Utilities Requirements). EPR, the future European Pressurized water Reactor, is the first installation of this type which will be operational from the year 2000 onwards, must fulfill the European requirements. EPR will serve as a test whether these requirements are realistic and well balanced. At the basic design stage of EPR, this paper concentrates on four main topics: the requirements which are new compared with existing reactors and which put a major challenge to the designer; the requirements today still open and the way they can be met by the EPR or not; the points for which already today the EPR special requirements exceed the EUR; the examples where the design of the EPR has given feedback which has led to a change of the EUR. EPR and EUR are different approaches to the reactor of the future. EUR is a set of requirements which leaves a flexibility to the designer while EPR is a real project which defines the technical solutions. EPR will fulfill the EUR and will at the same time serve as a test whether these requirements are realistic. EPR will also fulfill international requirements with minor changes. (J.S.). 7 figs

  16. EPR paradox revisited

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, C.D.; Scully, M.O.

    1978-07-01

    Einstein, Podolsky, and Rosen (EPR) argued in 1935 that quantum mechanics fails to give an adequate description of physical reality, and also cannot give a consistent wave-function description of certain phenomena. It is shown that a calculation based upon the reduced density matrix removes the formal inconsistency pointed out by EPR. The spirit of the present paper is that of a pedagogical review.

  17. Rapid-scan EPR imaging.

    Science.gov (United States)

    Eaton, Sandra S; Shi, Yilin; Woodcock, Lukas; Buchanan, Laura A; McPeak, Joseph; Quine, Richard W; Rinard, George A; Epel, Boris; Halpern, Howard J; Eaton, Gareth R

    2017-07-01

    In rapid-scan EPR the magnetic field or frequency is repeatedly scanned through the spectrum at rates that are much faster than in conventional continuous wave EPR. The signal is directly-detected with a mixer at the source frequency. Rapid-scan EPR is particularly advantageous when the scan rate through resonance is fast relative to electron spin relaxation rates. In such scans, there may be oscillations on the trailing edge of the spectrum. These oscillations can be removed by mathematical deconvolution to recover the slow-scan absorption spectrum. In cases of inhomogeneous broadening, the oscillations may interfere destructively to the extent that they are not visible. The deconvolution can be used even when it is not required, so spectra can be obtained in which some portions of the spectrum are in the rapid-scan regime and some are not. The technology developed for rapid-scan EPR can be applied generally so long as spectra are obtained in the linear response region. The detection of the full spectrum in each scan, the ability to use higher microwave power without saturation, and the noise filtering inherent in coherent averaging results in substantial improvement in signal-to-noise relative to conventional continuous wave spectroscopy, which is particularly advantageous for low-frequency EPR imaging. This overview describes the principles of rapid-scan EPR and the hardware used to generate the spectra. Examples are provided of its application to imaging of nitroxide radicals, diradicals, and spin-trapped radicals at a Larmor frequency of ca. 250MHz. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. EPR spectroscopy at DNP conditions

    International Nuclear Information System (INIS)

    Heckmann, J.; Goertz, St.; Meyer, W.; Radtke, E.; Reicherz, G.

    2004-01-01

    In terms of dynamic nuclear polarization (DNP) studies and systematic target material research it is crucial to know the EPR lineshape of the DNP relevant paramagnetic centers. Therefore in Bochum an EPR spectrometer has been implemented into the 4 He evaporation DNP facility in order to perform EPR studies at DNP conditions (B=2.5 T, T=1 K). The spectrometer hardware and performance as well as first results are presented

  19. EPR dosimetry of irradiated human teeth

    International Nuclear Information System (INIS)

    Rodas Duran, J.E.; Panzeri, H.; Mascarenhas, S.

    1985-01-01

    The determination of the absorbed radiation dose in man may be made by Electron Paramagnetic Resonance (EPR) spectroscopy of dental enamel. We analysed the EPR signals for dental enamel submitted to gamma radiation in doses between 1 Gy and 25 Gy. We conclude that independent of the type of tooth analysed there exists a linear relation between the EPR signals and the absorbed doses. These studies were extended to enamel irradiated with gamma rays and with X rays in doses between 0.1 Gy and 0.6 Gy. The graph of the intensity of the EPR signals as a function of the dose has a slope of 0.22. This calibration may be used to calculate the absorbed dose for humans from a measurement of the EPR signal from small samples of enamel taken from any permanent tooth. Finally we comment on some EPR studies of effects of radiation of milk teeth. (author)

  20. New Neutron Dosimeter

    CERN Multimedia

    2001-01-01

    CERN has been operating an Individual Dosimetry Service for neutrons for about 35 years. The service was based on nuclear emulsions in the form of film packages which were developed and scanned in the Service. In 1999, the supplier of theses packages informed CERN that they will discontinue production of this material. TIS-RP decided to look for an external service provider for individual neutron dosimetry. After an extensive market survey and an invitation for tender, a supplier that met the stringent technical requirements set up by CERN's host states for personal dosimeters was identified. The new dosimeter is based on a track-etching technique. Neutrons have the capability of damaging plastic material. The microscopic damage centres are revealed by etching them in a strong acid. The resulting etch pits can be automatically counted and their density is proportional to dose equivalent from neutrons. On the technical side, the new dosimeter provides an improved independence of its response from energy and th...

  1. MDEP Common Position No EPR-01 - Common positions on the EPR instrumentation and controls design

    International Nuclear Information System (INIS)

    2010-01-01

    The purpose of the EPR Working Group (EPRWG) of the Multinational Design Evaluation Program (MDEP) is to identify common positions among the regulators reviewing the EPR Instrumentation and Controls (I and C) Systems in order to: 1. Promote understanding of each country 's regulatory decisions and basis for the decisions, 2. Enhance communication among the members and with external stakeholders, 3. Identify areas where harmonization and convergence of regulations, standards, and guidance can be achieved or improved, and 4. Supports standardization of new reactor designs. Since January 2008, the EPR I and C Technical Expert Subgroup (TESG) members met five times to exchange information regarding their country 's review of the EPR I and C design. The EPR I and C TESG consists of regulators from China, Canada, Finland, France, the United Kingdom, and the United States. The information exchange includes presentation of each country 's review status and technical issues, sharing of guidance documents, and sharing of regulatory decision documents. The TESG focused on the following four core areas of the EPR I and C design: 1. I and C System Independence (particularly for data communications), 2. Level of Defense and Diversity (back-up systems), 3. Qualification/quality of digital platforms, 4. Categorization/classification of systems and functions. As meetings were conducted, some areas were emphasized more depending on the significance of the issues for each country. During the TESG interactions, it became apparent that there were aspects of the EPR design where the countries had common agreement. On November 2, 2009, three of the subgroup countries, France, Finland and the United Kingdom, issued a joint regulatory position on the EPR I and C design as result of the 'Groupe Permanent' meeting in France. This statement of common positions expands upon that joint regulatory position

  2. Radiation dosimeter assembly

    International Nuclear Information System (INIS)

    Seidel, J.G.

    1982-01-01

    A technique is disclosed for securing a thermoluminescent radiation dosimeter, used for monitoring underground radon gas in uranium prospecting, to a cup-like support member made of heavy gauge aluminum foil. A metalized film, consisting of an aluminum layer and a high tensile strength plastic layer, covers an aperture in the support members for the dosimeter. The film is secured by a high temperature adhesive to the support member, and both are capable of withstanding an annealing temperature of up to 300 0 C

  3. Performance testing of extremity dosimeters, Study 2

    International Nuclear Information System (INIS)

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

    1990-04-01

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

  4. A fibre optic dosimeter customised for brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Suchowerska, N. [Department of Radiation Oncology, Royal Prince Alfred Hospital, Camperdown, NSW 2050 (Australia); School of Physics, University of Sydney, NSW 2006 (Australia)], E-mail: Natalka@email.cs.nsw.gov.au; Lambert, J.; Nakano, T. [Department of Radiation Oncology, Royal Prince Alfred Hospital, Camperdown, NSW 2050 (Australia); School of Physics, University of Sydney, NSW 2006 (Australia); Law, S. [School of Physics, University of Sydney, NSW 2006 (Australia); Optical Fibre Technology Centre, University of Sydney, 206 National Innovation Centre, Australian Technology Park, Eveleigh, NSW 1430 (Australia); Elsey, J. [Bandwidth Foundry Pty Ltd, Australian Technology Park, NSW, 1430 (Australia); McKenzie, D.R. [School of Physics, University of Sydney, NSW 2006 (Australia)

    2007-04-15

    In-vivo dosimetry for brachytherapy cancer treatment requires a small dosimeter with a real time readout capability that can be inserted into the patient to determine the dose to critical organs. Fibre optic scintillation dosimeters, consisting of a plastic scintillator coupled to an optical fibre, are a promising dosimeter for this application. We have implemented specific design features to optimise the performance of the dosimeter for specific in-vivo dosimetry during brachytherapy. Two sizes of the BrachyFOD{sup TM} scintillation dosimeter have been developed, with external diameters of approximately 2 and 1 mm. We have determined their important dosimetric characteristics (depth dose relation, angular dependence, energy dependence). We have shown that the background signal created by Cerenkov and fibre fluorescence does not significantly affect the performance in most clinical geometries. The dosimeter design enables readout at less than 0.5 s intervals. The clinical demands of real time in-vivo brachytherapy dosimetry can uniquely be satisfied by the BrachyFOD{sup TM}.

  5. Use of EPR to Solve Biochemical Problems

    Science.gov (United States)

    Sahu, Indra D.; McCarrick, Robert M.; Lorigan, Gary A.

    2013-01-01

    EPR spectroscopy is a very powerful biophysical tool that can provide valuable structural and dynamic information on a wide variety of biological systems. The intent of this review is to provide a general overview for biochemists and biological researchers on the most commonly used EPR methods and how these techniques can be used to answer important biological questions. The topics discussed could easily fill one or more textbooks; thus, we present a brief background on several important biological EPR techniques and an overview of several interesting studies that have successfully used EPR to solve pertinent biological problems. The review consists of the following sections: an introduction to EPR techniques, spin labeling methods, and studies of naturally occurring organic radicals and EPR active transition metal systems which are presented as a series of case studies in which EPR spectroscopy has been used to greatly further our understanding of several important biological systems. PMID:23961941

  6. Directional Radiation Dosimeter for Area and Environmental Monitoring

    International Nuclear Information System (INIS)

    Manzoli, J.E.; Campos, V.P.; Moura, E.S.

    2009-01-01

    It is presented a dosimeter that is able to measure the photon exposure and the direction from where the radiation came from. Preliminary measurements performed by this new directional radiation dosimeter demonstrate its application. This dosimeter consists of a small lead cube with thermoluminescent discs on each face, placed in well known coordinates. Only one dosimeter of this kind indicates the direction of the radiation beam, if it came from a unique position. This study was conducted inside the radiation room of a Cobalt-60 Gamma Irradiator and the dosimeter indicated the source position

  7. Measurements of clinically significant doses of ionizing radiation using non-invasive in vivo EPR spectroscopy of teeth in situ

    International Nuclear Information System (INIS)

    Swartz, Harold M.; Iwasaki, Akinori; Walczak, Tadeusz; Demidenko, Eugene; Salikov, Ildar; Lesniewski, Piotr; Starewicz, Piotr; Schauer, David; Romanyukha, Alex

    2005-01-01

    There are plausible circumstances in which populations potentially have been exposed to doses of ionizing radiation that could cause direct clinical effects within days or weeks, but there is no clear knowledge as to the magnitude of the exposure to individuals. In vivo EPR is a method, perhaps the only such method that can differentiate among doses sufficiently to classify individuals into categories for treatment with sufficient accuracy to facilitate decisions on medical treatment. Individuals with significant risk then can have appropriate procedures initiated immediately, while those without a significant probability of acute effects could be reassured and removed from the need for further medical treatment. In its current state, the in vivo EPR dosimeter can provide estimates of absorbed dose of ±25 cGy in the range of 100->1000 cGy. This is expected to improve, with improvements in the resonator, the algorithm for calculating dose, and the uniformity of the magnetic field. In its current state of development, it probably is sufficient for most applications related to terrorism or nuclear warfare, for decision-making for action for individuals in regard to acute effects from exposure to ionizing radiation

  8. Dosimeter

    International Nuclear Information System (INIS)

    Thomson, I.

    1986-01-01

    This invention relates to a dosimeter for measuring ionizing radiation, and particularly to a dosimeter using an insulated gate field effect transistor (IGFET) as a sensor, having substantially improved accuracy. An IGFET is a field effect transistor fabricated on a silicon substrate and having an oxide insulator between the gate electrode and the silicon substrate. The gate electrode can be either metal or polycrystalline silicon dioxide. This invention overcomes previously-noted problems with IGFET sensors - the variation of threshold voltage with temperature, their inherent zero offset which varies from wafer to wafer, and the zero drift in threshold voltage - by measuring the differential threshold between two IGFET sensors exposed to the same radiation, in which one is biased into its conducting region, and the other is biased either off or to a conducting level less than the first. The measured differential threshold voltage between the two transistors will be a measure of the gamma radiation dose

  9. Intercomparison measurements with albedo neutron dosimeters

    International Nuclear Information System (INIS)

    Alberts, W.G.; Kluge, H.

    1994-01-01

    Since the introduction of the albedo dosimeter as the official personal neutron dosimeter the dosimetry services concerned have participated in intercomparison measurements at the PTB. Their albedo dosimeters were irradiated in reference fields produced by unmoderated and D 2 O-moderated 252 Cf neutron sources in the standard irradiation facility of the PTB. Six fields with fluences different in energy and angle distribution could be realised in order to determine the response of the albedo dosimeter. The dose equivalent values evaluated by the services were compared with the reference values of the PTB for the directional dose equivalent H'(10). The results turned out to be essentially dependent on the evaluation method and the choice of the calibration factors. (orig.) [de

  10. Application of solid dosimeter to radiation control

    International Nuclear Information System (INIS)

    Tsujimoto, Tadashi

    1988-01-01

    Individual exposure dose measuring devices are used to measure the dose of each person in facilities using radiations. Major devices of this type currently used in Japan include the film badge, thermoluminescence dosimeter, portable radiation dosimeter and fluorescent glass dosimeter. All of these devices except the portable radiation dosimeter are of a solid type. Various portable-type spatial dose rate measuring devices, generally called survey meters, are available to determine the spatial distribution of radiations. Major survey meters incorporates an ionization chamber, GM counter tube or scintillation counter, while BF 3 counting tubes are available for neutron measurement. Of these, the scintillation dosimeter is of a solid type. A new scintillation survey meter has recently been developed which incorporated a discrimination bias modulation circuit. Dosimeters incorporating an ionization chamber or a GM counter tube are generally used as portable alarms. Recently, a new solid-type alarm has been developed which incorporates a solicon radiation detector. Microcomputers are also used for self-diagnosis, data processing, automatic calibration, etc. (Nogami, K.)

  11. EPR studies of melanin from Cladosporium cladosporioides

    International Nuclear Information System (INIS)

    Pilawa, B.; Buszman, E.; Latocha, M.; Wilczok, T.

    1996-01-01

    Free radical properties of Cladosporium cladosporioides mycelium and melanin, and synthetic eumelanin and pheomelanin were studied by electron paramagnetic resonance method. Single EPR line and complex EPR spectrum with hyperfine splitting were measured for model DOPA-melanin and cysteinyldopa-melanin, respectively. EPR spectra of Cladosporium cladosporioides samples and pheomelanin show the same character. The concentration of paramagnetic centers in melanins isolated from Cladosporium cladosporioides is considerably higher than that of crude mycelium, whereas the EPR line widths are lower for mycelium than for melanin samples. For all analyzed samples the increase of EPR signals intensity with the increase of microwave power, and the decrease of intensities after saturation were observed the low values of microwave power sufficient for EPR lines saturation demonstrate that the spin-lattice relaxation times of unpaired electrons in melanins are long. (author)

  12. EPR in B physics and elsewhere

    International Nuclear Information System (INIS)

    Lipkin, H.J.; Tel Aviv Univ.; Argonne National Lab., IL

    1997-01-01

    The application of Einstein-Podolsky-Rosen correlations in Υ(4s) → B anti B decays to research in CP violation is the first and probably only use of EPR as a technique for research in new physics. Elsewhere highly sophisticated EPR projects question EPR and test its predictions to look for violations of quantum mechanics, hidden variables, Bell''s inequalities, etc

  13. Personnel neutron dosimeter evaluation and upgrade program

    International Nuclear Information System (INIS)

    Fix, J.J.; Brackenbush, L.W.; McDonald, J.C.; Roberson, P.L.; Holbrook, K.L.; Endres, G.W.R.; Faust, L.G.

    1983-01-01

    Evaluation of neutron dosimeters from twelve DOE laboratories involved about 2500 dosimeter irradiations at both PNL and the National Bureau of Standards (NBS) using neutrons of several energies and doses and several irradiations for good statistical analysis. The data and their analyses will be published later. The information evaluates accuracy, precision, lower dose detection, and energy response of dosimeters

  14. A thin alanine-polyethylene film dosimetry system with diffuse reflection spectrophotometric evaluation

    International Nuclear Information System (INIS)

    Zagorski, Z.P.; Rafalski, A.

    1995-01-01

    Characteristics of a new alanine dosimeter in the shape of a thin film, with the measurement of optical absorption of the CH 3 CHCOO - radical is described. That type of dosimeter, ALA/DRS (for diffuse reflection spectrophotometry) is compared, to an alanine dosimeter with EPR evaluation (ALA/EPR for short). In many respects the simple ALA/DRS version, as the alanine-polyethylene composite is superior. The paper shows the importance of the new experimental approach to free radical research in solid state radiation chemistry. (author). 7 refs., 3 figs

  15. 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,NMR,EPR...

  16. EPR STUDIES OF THERMALLY STERILIZED VASELINUM ALBUM.

    Science.gov (United States)

    Ramos, Paweł; Pilawa, Barbara

    2015-01-01

    Electron paramagnetic resonance (EPR) spectroscopy was used for examination of free radicals in thermally treated vaselinum album (VA). Thermal treatment in hot air as sterilization process was tested. Conditions of thermal sterilization were chosen according to the pharmaceutical norms. Vaselinum album was heated at the following conditions (T--temperature, t--time): T = 160°C and t = 120 min, T = 170°C and t = 60 min and T = 180°C and t = 30 min. The aim of this work was to determine concentration and free radical properties of thermally sterilized VA. EPR analysis for VA was done 15 min after sterilization. EPR measurements were done at room temperature. EPR spectra were recorded in the range of microwave power of 2.2-70 mW. g-Factor, amplitudes (A) and line width (ΔBpp) of the spectra were determined. The shape of the EPR spectra was analyzed. Free radical concentration (N) in the heated samples was determined. EPR spectra were not obtained for the non heated VA. EPR spectra were detected for all thermally sterilized samples. The spectra revealed complex character, their asymmetry depends on microwave power. The lowest free radicals concentration was found for the VA sterilized at 180°C during 30 min. EPR spectroscopy is proposed as the method useful for optimization of sterilization process of drugs.

  17. 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.

  18. Mexican gems as thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    Azorin N, J.

    1979-01-01

    The possibility of using naturally ocurring mexican gems as thermoluminescent dosimeters (TLD) was investigated. Twelve types of gems were irradiated with X and gamma rays in order to determinate their dosimetric properties. Three of these gems showed favorable thermoluminescent characteristics compared with commercial thermoluminescent dosimeters. The plots of their thermoluminescent response as a function of gamma dose are straight lines on full log paper in the dose range 10 -2 to 10 2 Gy. The energy dependence is very strong to low energies of the radiation. Their fading was found to be about 5%/yr. and they may be annealed as reused without loss in sensitivity. Therefore, these gems can be used as X and gamma radiation dosimeters. (author)

  19. Evaluation of personal integrating dosimeters

    International Nuclear Information System (INIS)

    Correa, C.A.; Bisauta, Mauricio A.

    2007-01-01

    The objective of this work is to analyze the different types of dosimeters present in the international market that are used to provide personal dose monitoring, specifically for external gamma and beta radiation, Hp(10) and Hp (0,07), as well as to add comments of advances in the field of passive and operative dosimetry, and the changes that are being produced in the regulating policy in other countries regarding the use of this devices. The technical specification of each dosimeter has been extracted of different catalogues of products. To conclude, the importance has been stressed in a proper selection of dosimeters with its advantages and disadvantages before its use. (author) [es

  20. Research on the formula of radiochromic film dosimeters

    International Nuclear Information System (INIS)

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

    2006-10-01

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

  1. Development and dosimetric evaluation of radiochromic PCDA vesicle gel dosimeters

    International Nuclear Information System (INIS)

    Sun, P.; Fu, Y.C.; Hu, J.; Hao, N.; Huang, W.; Jiang, B.

    2016-01-01

    The gel dosimeter has the unique capacity in recording radiation dose distribution in three dimensions (3D), which has the specific advantages in dosimetry measurements where steep dose gradients exist, such as in intensity-modulated radiation therapy (IMRT), brachytherapy and so on. Some 3D dosimeters, such as Fricke gel dosimeters, polymer gel dosimeters, the PRESAGE plastic dosimeters and micelle gel dosimeters have appeared recently. However, there are several disadvantages of these 3D dosimeters limit their application in radiotherapy dose verification. In this study, a novel radiochromic gel dosimeter for 3D dose verification of radiotherapy was developed by dispersing nanovesicles self-assembled by 10,12-pentacosadiynoic acid (PCDA) into the tissue equivalence gel matrix. The characteristics of radiochromic PCDA vesicle gel dosimeters were evaluated. The results indicate that these radiochromic gel dosimeters have good linear dose response to X-ray irradiation in the dose range of 2–100 Gy. In addition, the radiochromic gel dosimeters breakthrough the limitations of the existing gel dosimeters such as diffusion effect, post-radiation effect, and poor forming ability. The response of the gel dosimeter does not show any dose rate dependence, energy dependence and temperature effect, and there was no obvious difference in the gel response between single and cumulative dose of fractional irradiation. Hence, the radiochromic PCDA vesicle gel dosimeters developed in this study could be generally applied to 3D dose verification in radiotherapy. - Highlights: • A novel radiochromic gel dosimeter was developed by dispersing PCDA nanovesicles into the tissue equivalence gel matrix. • This nanovesicle overcomes the dose image blurring caused by the diffusion of monomer molecules. • This nanovesicle limits the polymer chain growth, so as to reduce the post-radiation effect. • The gel matrixes possess excellent tissue equivalence and elastic strength, which

  2. Retrospective individual dosimetry using luminescence and EPR after radiation accidents

    International Nuclear Information System (INIS)

    Goeksu, H.Y.; Wieser, A.; Ulanovsky, A.

    2007-01-01

    In areas where radiation dose monitoring has not been performed, it is essential to use material available in the environment be able to rapidly assess doses to individuals for immediate emergency medical care or for general estimation of the radiological consequences. It was shown that certain types of telephone cards containing microchips have the potential to be used as individual radiation dosimeters in emergency situations to detect doses over 250 mGy by luminescence measurements. In order to understand the dosimetric properties of chip cards, the components obtained from INFINIEON Company at various stages of production were used for luminescence measurements. It is found that the protecting layer used above the chips so called 'globe top' is the main source of radiation induced signal in chip cards. The globe top produced by INFINIEON at that stage is found to contain SiO2 and Epoxy. In order to improve the dosimetric properties of the chip cards, the raw material of the globe top is mixed with phosphorous material. The variation of the dose response and the detection limit with respect to the amount and the type of the phosphor added to the globe top is investigated using thermo luminescence (TL) and infrared stimulated luminescence (IRSL). Taking into account the rapid changes in chip card producing technology such as material properties, size of the globe top, a special-purpose software tool has been developed to calculate integral free-in-air kerma or organ dose for a given energy dose response of the card and irradiation conditions (photon fluence spectrum and irradiation geometry). It is also shown that adding phosphors powders such as Al2O3:C, LiF:Cu or BeO to SiO2/epoxy mixture of the globe top material, radiation detection limit of chip cards can be reduced as low as a few mGy but the presence of an initial signal in UV cured material as well as gradual increase of the signal are found to be the main limiting factors for detection of low doses

  3. Magnetic field dosimeter development

    International Nuclear Information System (INIS)

    Lemon, D.K.; Skorpik, J.R.; Eick, J.L.

    1980-09-01

    In recent years there has been increased concern over potential health hazards related to exposure of personnel to magnetic fields. If exposure standards are to be established, then a means for measuring magnetic field dose must be available. To meet this need, the Department of Energy has funded development of prototype dosimeters at the Battelle Pacific Northwest Laboratory. This manual reviews the principle of operation of the dosimeter and also contains step-by-step instructions for its operation

  4. Pharmaceutical applications of in vivo EPR

    International Nuclear Information System (INIS)

    Maeder, K.

    1998-01-01

    The aim of this article is to discuss the applications of in vivo EPR in the field of pharmacy. In addition to direct detection of free radical metabolites and measurement of oxygen, EPR can be used to characterize the mechanisms of drug release from biodegradable polymers. Unique information about drug concentration, the microenvironment (viscosity, polarity, pH) and biodistribution (by localized measurement or EPR Imaging) can be obtained. (author)

  5. Use of wrist albedo neutron dosimeters

    International Nuclear Information System (INIS)

    Hankins, D.E.

    1983-01-01

    We are developing a wrist dosimeter that can be used to measure the exposure at the wrist to x-rays, gamma rays, beta-particles, thermal neutrons and fast neutrons. It consists of a modified Hankins Type albedo neutron dosimeter and also contains three pieces of CR-39 plastic. ABS plastic in the form of an elongated hemisphere provides the beta and low energy x-ray shielding necessary to meet the requirement of depth dose measurements at 1 cm. The dosimeter has a beta window located in the side of the hemisphere oriented towards an object being held in the hands. A TLD 600 is positioned under the 1 cm thick ABS plastic and is used to measure the thermal neutron dose. At present we are using Velcro straps to hold the dosimeter on the inside of the wrist. 9 figures

  6. Contribution of Harold M. Swartz to In Vivo EPR and EPR Dosimetry

    International Nuclear Information System (INIS)

    Gallez, Bernard

    2016-01-01

    In 2015, we are celebrating half a century of research in the application of Electron Paramagnetic Resonance (EPR) as a biodosimetry tool to evaluate the dose received by irradiated people. During the EPR Biodose 2015 meeting, a special session was organized to acknowledge the pioneering contribution of Harold M. (Hal) Swartz in the field. The article summarizes his main contribution in physiology and medicine. Four emerging themes have been pursued continuously along his career since its beginning: (1) radiation biology; (2) oxygen and oxidation; (3) measuring physiology in vivo; and (4) application of these measurements in clinical medicine. The common feature among all these different subjects has been the use of magnetic resonance techniques, especially EPR. In this article, you will find an impressionist portrait of Hal Swartz with the description of the 'making of' this pioneer, a time-line perspective on his career with the creation of three National Institutes of Health-funded EPR centers, a topic-oriented perspective on his career with a description of his major contributions to Science, his role as a mentor and his influence on his academic children, his active role as founder of scientific societies and organizer of scientific meetings, and the well-deserved international recognition received so far. (author)

  7. Evaluation of fading factor and self-dose for glass dosimeter and thermoluminescence dosimeter

    International Nuclear Information System (INIS)

    Yamasaki, T.; Yamanishi, H.; Miyake, H.; Komura, K.

    2000-01-01

    The glass dosimeter (GD) and thermoluminescence dosimeter (TLD) are both passive radiation detectors. They are often used for measuring environmental radiation. In order to measure low dose rate preciously, it is important to evaluate decreased dose due to fading and self-dose during the exposure period. We evaluate the fading factor and self-dose of thee passive detectors, GD and TLD. We select Ogoya tunnel for the experiment. The tunnel is suitable field for measuring faded dose and self-dose because it is low cosmic radiation. At the center of the tunnel, the intensity of cosmic ray is reduced to about 1/177 than the outside of the funnel. We prepared two sets of dosimeters. One set consists of five GDs, five TLDs and some pre-irradiated GDs and TLDs that are exposed to standard radiation of 4 mGy by Cs-137. These dosimeters are put in the 10 cm thick lead box in order to shield the terrestrial gamma ray. One set is located at the center of the tunnel and the other is the outside of the funnel. The dosimeters were exposed for ten months, from May 1998 to March 1999. After the exposure, the readers of dosimeters are carried into the funnel to read out the signals promptly as soon as taking out the dosimeters. As a result of the measurement, four kinds of data are taken for GD and TLD respectively. Assumed that the self-dose and cosmic ray are constant during exposure, the four independent unknown quantities, a self-dose a dose due to cosmic ray and a fading coefficient at the center of the tunnel and at the outside, are considered. Therefore four simultaneous equations should be obtained. From these examinations, the faded dose of GD is less than 1%, but that of TLD is about 16% during ten months. The coefficient for compensation of fading of GD and TLD is given as the half of the each value. At the outside of the tunnel, the measured dose rate of cosmic ray that can pass through the 10 cm lead is evaluated to be about 16 nGy/h by both detectors. The self

  8. EPR and transient capacitance studies on electron-irradiated silicon solar cells

    Science.gov (United States)

    Lee, Y. H.; Cheng, L. J.; Mooney, P. M.; Corbett, J. W.

    1977-01-01

    One and two ohm-cm solar cells irradiated with 1 MeV electrons at 30 C were studied using both EPR and transient capacitance techniques. In 2 ohm-cm cells, Si-G6 and Si-G15 EPR spectra and majority carrier trapping levels at (E sub V + 0.23) eV and (E sub V + 0.38) eV were observed, each of which corresponded to the divacancy and the carbon-oxygen-vacancy complex, respectively. In addition, a boron-associated defect with a minority carrier trapping level at (E sub C -0.27) eV was observed. In 1 ohm-cm cells, the G15 spectrum and majority carrier trap at (E sub V + 0.38) eV were absent and an isotropic EPR line appeared at g = 1.9988 (+ or - 0.0003); additionally, a majority carrier trapping center at (E sub V + 0.32) eV, was found which could be associated with impurity lithium. The formation mechanisms of these defects are discussed according to isochronal annealing data in electron-irradiated p-type silicon.

  9. The EPR paradox revisited

    International Nuclear Information System (INIS)

    Cantrell, C.D.; Scully, M.O.

    1978-01-01

    Einstein, Podolsky and Rosen (EPR) argued in 1935 that quantum mechanics fails to give an adequate description of physical reality, and also cannot give a consistent wave-function description of certain phenomena. The authors show that a calculation based upon the reduced density matrix removes the formal inconsistency pointed out by EPR. The spirit of the present paper is that of a pedagogical review. (Auth.)

  10. Comparison of electronic digital alarm dosimeter with TLD

    International Nuclear Information System (INIS)

    Kumar, Pankaj; Pandey, J.P.N.; Shinde, A M.; Purohit, R.G.; Sarkar, P.K.

    2012-01-01

    Control of exposure of radiation workers on day to day basis has been made easy by use of semiconductor based electronic digital dosimeter. Additional dose constraints of 10 mSv for occupational radiation workers have made it essential to use such type of digital personal monitoring devices. In addition to conventional ionisation chamber based direct reading dosimeters, additional 35 semiconductor based digital dosimeters model MGP DMC 2000 S were used for the monitoring of personal exposure of radiation workers in a spent fuel reprocessing plant. Though better least count and good performance over a wide range of dose rate are claimed by the manufacture, before making use of such dosimeter on large scale, validation of its performance is required to be checked. In this paper, an effort is made to determine the performance of digital dosimeters, by exposing these digital dosimeters in combination with TLDs at different radiation levels and obtained results were compared and analysed

  11. EPR spectroscopic investigation of psoriatic finger nails.

    Science.gov (United States)

    Nakagawa, Kouichi; Minakawa, Satoko; Sawamura, Daisuke

    2013-11-01

    Nail lesions are common features of psoriasis and found in almost half of the patients. However, there is no feasible spectroscopic method evaluating changes and severity of nail psoriasis. EPR (electron paramagnetic resonance) might be feasible for evaluating nail conditions in the patients of psoriasis. Finger nails of five cases with nail psoriasis, (three females and two males) were examined. Nail samples were subjected to the EPR assay. The small piece of the finger nail (1.5 × 5 mm(2)) was incubated in ~50 μM 5-DSA (5-doxylstearic acid) aqueous solutions for about 60 min at 37°C. After rinsing and wiping off the excess 5-DSA solution, the nail samples were measured by EPR. EPR spectra were analyzed using the intensity ratio (Fast/Slow) of the two motions at the peaks of the lower magnetic field. We observed two distinguishable sites on the basis of the EPR results. In addition, the modern EPR calculation was performed to analyze the spectra obtained. The nail psoriasis-related region is 2~3 times higher than that of the control. The present EPR results show that there are two distinguishable sites in the nail. In the case of nail psoriasis, the fragile components are 2~3 times more than those of the control. Thus, the EPR method is thought to be a novel and reliable method of evaluating the nail psoriasis. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. EPR dosimetry with tooth enamel: A review

    International Nuclear Information System (INIS)

    Fattibene, Paola; Callens, Freddy

    2010-01-01

    When tooth enamel is exposed to ionizing radiation, radicals are formed, which can be detected using electron paramagnetic resonance (EPR) techniques. EPR dosimetry using tooth enamel is based on the (presumed) correlation between the intensity or amplitude of some of the radiation-induced signals with the dose absorbed in the enamel. In the present paper a critical review is given of this widely applied dosimetric method. The first part of the paper is fairly fundamental and deals with the main properties of tooth enamel and some of its model systems (e.g., synthetic apatites). Considerable attention is also paid to the numerous radiation-induced and native EPR signals and the radicals responsible for them. The relevant methods for EPR detection, identification and spectrum analyzing are reviewed from a general point of view. Finally, the needs for solid-state modelling and studies of the linearity of the dose response are investigated. The second part is devoted to the practical implementation of EPR dosimetry using enamel. It concerns specific problems of preparation of samples, their irradiation and spectrum acquisition. It also describes how the dosimetric signal intensity and dose can be retrieved from the EPR spectra. Special attention is paid to the energy dependence of the EPR response and to sources of uncertainties. Results of and problems encountered in international intercomparisons and epidemiological studies are also dealt with. In the final section the future of EPR dosimetry with tooth enamel is analyzed.

  13. Personal noise dosimeters: Accuracy and reliability in varied settings

    Directory of Open Access Journals (Sweden)

    Sheri Lynn Cook-Cunningham

    2014-01-01

    Full Text Available This study investigated the accuracy, reliability, and characteristics of three brands of personal noise dosimeters (N = 7 units in both pink noise (PN environments and natural environments (NEs through the acquisition of decibel readings, Leq readings and noise doses. Acquisition periods included repeated PN conditions, choir room rehearsals and participant (N = 3 Leq and noise dosages procured during a day in the life of a music student. Among primary results: (a All dosimeters exhibited very strong positive correlations for PN measurements across all instruments; (b all dosimeters were within the recommended American National Standard Institute (ANSI SI.25-1991 standard of ±2 dB (A of a reference measurement; and (c all dosimeters were within the recommended ANSI SI.25-1991 standard of ±2 dB (A when compared with each other. Results were discussed in terms of using personal noise dosimeters within hearing conservation and research contexts and recommendations for future research. Personal noise dosimeters were studied within the contexts of PN environments and NEs (choral classroom and the day in the life of collegiate music students. This quantitative study was a non-experimental correlation design. Three brands of personal noise dosimeters (Cirrus doseBadge, Quest Edge Eg5 and Etymotic ER200D were tested in two environments, a PN setting and a natural setting. There were two conditions within each environment. In the PN environment condition one, each dosimeter was tested individually in comparison with two reference measuring devices (Ivie and Easera while PN was generated by a Whites Instrument PN Tube. In condition two, the PN procedures were replicated for longer periods while all dosimeters measured the sound levels simultaneously. In the NE condition one, all dosimeters were placed side by side on a music stand and recorded sound levels of choir rehearsals over a 7-h rehearsal period. In NE, condition two noise levels were measured

  14. EPR: what has it taught us

    International Nuclear Information System (INIS)

    Stapp, H.P.

    1985-05-01

    This symposium commemorating the fiftieth anniversary of the paper of Einstein, Podolsky, and Rosen is a fitting place to review what that work and its sequels have taught us. Prima facie, the EPR paper appears to have been exceedingly counter-productive for the following reasons: (1) The work was quickly rebutted by Bohr, and this rebuttal was apparently accepted by most workers in the field. (2) Scientists who adopted the position advocated by Bohr have produced, in the intervening fifty years, a marvelous body of useful theory, whereas those following the course suggested by EPR have produced nothing of any certified practical value. (3) It has been shown by Bell that the conclusion reached by EPR is incompatible with their assumptions. Chemists and physicists have recently begun to examine the behavior of quantum mechanical systems that are very small, yet large enough to influence their environment in ways that appreciably modify their own behavior, vis-a-vis the behavior they would have if isolated. Because these systems are neither small enough to be treated as isolated (or as residing in a classically described environment) between preparation and detection, nor large enough to be treated classically, they do not conform to the format demanded by the Copenhagen interpretation. Indeed, the behavior of these systems depends on ontological considerations that were irrelevant in the situations covered by the Copenhagen interpretation, and that were systematically ignored in that interpretation. Scientists now face the task of enlarging the scope of quantum theory to cover these new situations, and comparing the empirical consequences of various ontological assumptions. 17 refs

  15. Floating Gate CMOS Dosimeter With Frequency Output

    Science.gov (United States)

    Garcia-Moreno, E.; Isern, E.; Roca, M.; Picos, R.; Font, J.; Cesari, J.; Pineda, A.

    2012-04-01

    This paper presents a gamma radiation dosimeter based on a floating gate sensor. The sensor is coupled with a signal processing circuitry, which furnishes a square wave output signal, the frequency of which depends on the total dose. Like any other floating gate dosimeter, it exhibits zero bias operation and reprogramming capabilities. The dosimeter has been designed in a standard 0.6 m CMOS technology. The whole dosimeter occupies a silicon area of 450 m250 m. The initial sensitivity to a radiation dose is Hz/rad, and to temperature and supply voltage is kHz/°C and 0.067 kHz/mV, respectively. The lowest detectable dose is less than 1 rad.

  16. Neutron dosimeter utilizing CR-39

    International Nuclear Information System (INIS)

    Souza, H.V.C. de.

    1991-05-01

    A personnel neutron dosimeter has been developed with discretization in a wide range of energies of real interest, utilizing the CR-39 polymer, to detect recoil protons in the fast range, and alpha particles in the thermal and epithermal ranges, with possibility to be disposed in the IRD/CNEN's conventional film badge suport. They are presented, abstractly, the difficulties and importance of the neutron dosimetry, beyond the general objectives that motivated this work execution. The details of the materials utilized in the dosimeter confection, and the experimental methodology employed to obtain the performance curves are presented. The results about linearity response of the dosimeter with respect to equivalent dose, in a wide range of doses, and about the verified angular dependence are analysed. (author)

  17. Intercomparison of high energy neutron personnel dosimeters

    International Nuclear Information System (INIS)

    McDonald, J.C.; Akabani, G.; Loesch, R.M.

    1993-03-01

    An intercomparison of high-energy neutron personnel dosimeters was performed to evaluate the uniformity of the response characteristics of typical neutron dosimeters presently in use at US Department of Energy (DOE) accelerator facilities. It was necessary to perform an intercomparison because there are no national or international standards for high-energy neutron dosimetry. The testing that is presently under way for the Department of Energy Laboratory Accreditation Program (DOELAP) is limited to the use of neutron sources that range in energy from about 1 keV to 2 MeV. Therefore, the high-energy neutron dosimeters presently in use at DOE accelerator facilities are not being tested effectively. This intercomparison employed neutrons produced by the 9 Be(p,n) 9 B interaction at the University of Washington cyclotron, using 50-MeV protons. The resulting neutron energy spectrum extended to a maximum of approximately 50-MeV, with a mean energy of about 20-MeV. Intercomparison results for currently used dosimeters, including Nuclear Type A (NTA) film, thermoluminescent dosimeter (TLD)-albedo, and track-etch dosimeters (TEDs), indicated a wide variation in response to identical doses of high-energy neutrons. Results of this study will be discussed along with a description of plans for future work

  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...... tumbling radicals are often broad and relatively poor in distinctive features, a number of techniques have been developed that allow a wealth of information to be obtained about the nature, site, and reactions of such radicals. This article summarizes recent developments in this area and reviews selected...... examples of radical formation on proteins....

  19. Contribution of Harold M. Swartz to In Vivo EPR and EPR Dosimetry.

    Science.gov (United States)

    Gallez, Bernard

    2016-12-01

    In 2015, we are celebrating half a century of research in the application of Electron Paramagnetic Resonance (EPR) as a biodosimetry tool to evaluate the dose received by irradiated people. During the EPR Biodose 2015 meeting, a special session was organized to acknowledge the pioneering contribution of Harold M. (Hal) Swartz in the field. The article summarizes his main contribution in physiology and medicine. Four emerging themes have been pursued continuously along his career since its beginning: (1) radiation biology; (2) oxygen and oxidation; (3) measuring physiology in vivo; and (4) application of these measurements in clinical medicine. The common feature among all these different subjects has been the use of magnetic resonance techniques, especially EPR. In this article, you will find an impressionist portrait of Hal Swartz with the description of the 'making of' this pioneer, a time-line perspective on his career with the creation of three National Institutes of Health-funded EPR centers, a topic-oriented perspective on his career with a description of his major contributions to Science, his role as a mentor and his influence on his academic children, his active role as founder of scientific societies and organizer of scientific meetings, and the well-deserved international recognition received so far. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Characterization of Melanin Radicals in Paraffin-embedded Malignant Melanoma and Nevus Pigmentosus Using X-band EPR and EPR Imaging.

    Science.gov (United States)

    Nakagawa, Kouichi; Minakawa, Satoko; Sawamura, Daisuke; Hara, Hideyuki

    2017-01-01

    Continuous wave electron paramagnetic resonance (CW EPR) and X-band (9 GHz) EPR imaging (EPRI) were used to nondestructively investigate the possible differentiation between malignant melanoma (MM) and nevus pigmentosus (NP) melanin radicals in paraffin-embedded specimens. The EPR spectra of both samples were analyzed using linewidth, spectral pattern, and X-band EPRI. The CW-EPR spectra of the MM showed an additional signal overlap. Eumelanin- and pheomelanin-related radicals were observed in the MM specimens. The EPR results revealed that the peak-to-peak linewidths (ΔH pp ) of paraffin-embedded MM and NP samples were 0.65 ± 0.01 and 0.69 ± 0.01 mT, respectively. The g-value was 2.005 for both samples. Moreover, the two-dimensional (2D) EPRI of the MM showed different signal intensities at the different tumor stages, unlike the NP, which displayed fewer variations in signal intensity. Thus, the present results suggest that EPR and 2D EPRI can be useful for characterization of the two melanin radicals in the MM and for determination of their size and concentration.

  1. Bronchial dosimeter for radon progeny

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, T.K.; Yu, K.N.; Nikezic, D.; Haque, A.K.M.M. [City University of Hong Kong, Hong Kong (China); Vucic, D. [Faculty of Technology, University of Nis, Lescovac (Yugoslavia)

    2000-05-01

    Traditionally, assessments of the bronchial dose from radon progeny were carried out by measuring the unattached fraction (f{sub p}) of potential alpha energy concentration (PAEC), the total PAEC, activity median diameters (AMDs) and equilibrium factor, and then using dosimetric lung models. A breakthrough was proposed by Hopke et al. (1990) to use multiple metal wire screens to mimic the deposition properties of radon progeny in the nasal (N) and tracheobronchial (T-B) regions directly. In particular, they were successful in using four layers of 400-mesh wire screens with a face velocity of 12 cm s{sup -1} for the simulation of radon progeny deposition in the T-B region. Oberstedt and Vanmarcke (1995) carried out precise calibrations for the system, and named the system as the 'bronchial dosimeter'. Based on these, Yu and Guan (1998) proposed a portable bronchial dosimeter similar to a normal measurement system for radon progeny or PAEC and consisted of only a single sampler and employed only one 400-mesh wire screen and one filter. However, all these 'bronchial dosimeters' in fact only determined the fraction of potential alpha energy from radon progeny deposited in the T-B region, which required certain assumptions and calculations to further give the final bronchial dose. In the present work, a true 'bronchial dosimeter' was designed, which consisted of three 400-mesh wire screens and a filter. With a face velocity of 11 cm s{sup -1}, the deposition pattern on the wire screens was found to satisfactorily match the variation of the dose conversion factor (in the unit of mSv/WLM) with the size of radon progeny from 1 to 1000 nm. In this way, this bronchial dosimeter directly gave the bronchial dose from the alpha counts recorded on the wire-screens and the filter paper. With the development of this bronchial dosimeter, the present practice of 'dose estimation' from large-scale radon surveys can be replaced by large

  2. EPR meeting international safety standards with margin

    International Nuclear Information System (INIS)

    Mazurkiewicz, S.M.; Brauns, J.; Blombach, J.

    2005-01-01

    The EPR provides technology that offers a solution to the market's need for safe, economic power. The EPR was originally developed through a joint effort between Framatome ANP and Siemens by incorporating the best technological features from the French and German nuclear reactor fleets into a cost-competitive product capable of international licensing. As such, the EPR is a global product with commercial units currently being built in Finland at the Olkiluoto site, and planned for France, at the Flamanville site. Framatome ANP has recently proposed four EPR units to China in response to a request for vendor bids. In addition, Framatome ANP has announced their intent to pursue design certification with the United States Nuclear Regulatory Commission (NRC). This paper discusses how EPR's innovative safety philosophy ensures compliance with international safety standards for advanced light-water reactors (ALWRs). (author)

  3. EPR meeting international safety standards with margin

    International Nuclear Information System (INIS)

    Mazurkiewicz, S.M.; Brauns, J.; Blombach, J.

    2005-01-01

    The EPR provides technology that offers a solution to the market's need for safe, economic power. The EPR was originally developed through a joint effort between Framatome ANP and Siemens by incorporating the best technological features from the French and German nuclear reactor fleets into a cost-competitive product capable of international licensing. As such, the EPR is a global product with commercial units currently being built in Finland at the Olkiluoto site, and planned for France, at the Flamanville site. Framatome ANP has recently proposed four EPR units to China in response to a request for vendor bids. In addition, Framatome ANP has announced their intent to pursue design certification in with the United States Nuclear Regulatory Commission (NRC). This paper discusses how EPR's innovative safety philosophy ensures compliance with international safety standards for advanced light-water reactors (ALWRs). (author)

  4. Compton effect thermally activated depolarization dosimeter

    Science.gov (United States)

    Moran, Paul R.

    1978-01-01

    A dosimetry technique for high-energy gamma radiation or X-radiation employs the Compton effect in conjunction with radiation-induced thermally activated depolarization phenomena. A dielectric material is disposed between two electrodes which are electrically short circuited to produce a dosimeter which is then exposed to the gamma or X radiation. The gamma or X-radiation impinging on the dosimeter interacts with the dielectric material directly or with the metal composing the electrode to produce Compton electrons which are emitted preferentially in the direction in which the radiation was traveling. A portion of these electrons becomes trapped in the dielectric material, consequently inducing a stable electrical polarization in the dielectric material. Subsequent heating of the exposed dosimeter to the point of onset of ionic conductivity with the electrodes still shorted through an ammeter causes the dielectric material to depolarize, and the depolarization signal so emitted can be measured and is proportional to the dose of radiation received by the dosimeter.

  5. Calibration and testing of the DMG gamma dosimeter

    International Nuclear Information System (INIS)

    Dolgirev, E.I.

    1987-01-01

    25-1000 nGy/h (2.5-1000 μrad/h) absorbed dose gamma dosimeter for measuring the efficient equivalent irradiation dose for population is developed. It has two subranges 1000 nGy/h and 250 nGy/h. Results of dosimeter calibration and testing are presented. The dosimeter error for both subranges is less than 10%

  6. CRRES dosimeter simulations

    International Nuclear Information System (INIS)

    Auchampaugh, G.; Cayton, T.

    1993-04-01

    Conflicting data have been obtained from electron instruments aboard CRRES (Combined Release and Radiation Effects Satellite). To gain insight and to help in the interpretation of the data, we have calculated electron- and proton-flux and dose response functions for the four domes of the CRRES dosimeters using the Los Alamos Monte Carlo radiation transport codes. The response functions were calculated for electron and proton energies representative of those present in the space radiation environment. We also calculated the response of the dosimeters to a model radiation environment for orbit 607, which occurred on April 1, 1991 and compared the results to the measured values. The electron and proton components of the radiation environment were calculated using the solar maximum versions of the AE8 and AP8 models, namely, AE8MAX and AP8MAX. To facilitate the second task, we wrote two FORTRAN programs (CRRESunderscoreSIMP for AP8MAX and CRRESunderscoreSIME for AE8MAX) to read in a standard CRRES data file and to produce a comparison file of the calculated and measured values for all four dosimeter domes.The FORTRAN code will be available to the Phillips Laboratory for their use in making comparisons to other orbital data

  7. Dose measurement during defectoscopic work using electronic personal dosimeters

    International Nuclear Information System (INIS)

    Smoldasova, J.

    2008-01-01

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

  8. 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

  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. Reactor Gamma Heat Measurements with Calorimeters and Thermoluminescence Dosimeters

    DEFF Research Database (Denmark)

    Haack, Karsten; Majborn, Benny

    1973-01-01

    Intercomparison measurements of reactor γ-ray heating were carried out with calorimeters and thermoluminescence dosimeters. Within the measurement uncertainties the two methods yield coincident results. In the actual measurement range thermoluminescence dosimeters are less accurate than calorimet......Intercomparison measurements of reactor γ-ray heating were carried out with calorimeters and thermoluminescence dosimeters. Within the measurement uncertainties the two methods yield coincident results. In the actual measurement range thermoluminescence dosimeters are less accurate than...... calorimeters, but possess advantages such as a small probe size and the possibility of making simultaneous measurements at many different positions. Hence, thermoluminescence dosimeters may constitute a valuable supplement to calorimeters for reactor γ-ray heating measurements....

  11. Role of gel dosimeters in boron neutron capture therapy

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  12. Polymer gel dosimeter based on itaconic acid

    International Nuclear Information System (INIS)

    Mattea, Facundo; Chacón, David

    2015-01-01

    A new polymeric dosimeter based on itaconic acid and N, N’-methylenebisacrylamide was studied. The preparation method, compositions of monomer and crosslinking agent and the presence of oxygen in the dosimetric system were analyzed. The resulting materials were irradiated with an X-ray tube at 158 cGy/min, 226 cGy min and 298 cGy/min with doses up to 1000 Gy. The dosimeters presented a linear response in the dose range 75–1000 Gy, sensitivities of 0.037 1/Gy at 298 cGy/min and an increase in the sensitivity with lower dose rates. One of the most relevant outcomes in this study was obtaining different monomer to crosslinker inclusion in the formed gel for the dosimeters where oxygen was purged during the preparation method. This effect has not been reported in other typical dosimeters and could be attributed to the large differences in the reactivity among these species. - Highlights: • A novel polymer gel dosimeters based on itaconic acid is presented and characterized. • The typical linear trend of the dose behavior in a specific dose range was found. • Different gel structures were formed when oxygen and an antioxidant were present. • Absorbed dose is univocally correlated with optic absorbance and Raman spectroscopy. • Itaconic acid appears as a reliable radiation dosimeter that may be further improved.

  13. Pulsed-High Field/High-Frequency EPR Spectroscopy

    Science.gov (United States)

    Fuhs, Michael; Moebius, Klaus

    Pulsed high-field/high-frequency electron paramagnetic resonance (EPR) spectroscopy is used to disentangle many kinds of different effects often obscured in continuous wave (cw) EPR spectra at lower magnetic fields/microwave frequencies. While the high magnetic field increases the resolution of G tensors and of nuclear Larmor frequencies, the high frequencies allow for higher time resolution for molecular dynamics as well as for transient paramagnetic intermediates studied with time-resolved EPR. Pulsed EPR methods are used for example for relaxation-time studies, and pulsed Electron Nuclear DOuble Resonance (ENDOR) is used to resolve unresolved hyperfine structure hidden in inhomogeneous linewidths. In the present article we introduce the basic concepts and selected applications to structure and mobility studies on electron transfer systems, reaction centers of photosynthesis as well as biomimetic models. The article concludes with an introduction to stochastic EPR which makes use of an other concept for investigating resonance systems in order to increase the excitation bandwidth of pulsed EPR. The limited excitation bandwidth of pulses at high frequency is one of the main limitations which, so far, made Fourier transform methods hardly feasible.

  14. Electron paramagnetic resonance (EPR) in medical dosimetry

    International Nuclear Information System (INIS)

    Schauer, David A.; Iwasaki, Akinori; Romanyukha, Alexander A.; Swartz, Harold M.; Onori, Sandro

    2006-01-01

    This paper describes the fundamentals of electron paramagnetic resonance (EPR) and its application to retrospective measurements of clinically significant doses of ionizing radiation. X-band is the most widely used in EPR dosimetry because it represents a good compromise between sensitivity, sample size and water content in the sample. Higher frequency bands (e.g., W and Q) provide higher sensitivity, but they are also greatly influenced by water content. L and S bands can be used for EPR measurements in samples with high water content but they are less sensitive than X-band. Quality control for therapeutic radiation facilities using X-band EPR spectrometry of alanine is also presented

  15. A sub-Kelvin cryogen-free EPR system.

    Science.gov (United States)

    Melhuish, Simon J; Stott, Chloe; Ariciu, Ana-Maria; Martinis, Lorenzo; McCulloch, Mark; Piccirillo, Lucio; Collison, David; Tuna, Floriana; Winpenny, Richard

    2017-09-01

    We present an EPR instrument built for operation at Q band below 1K. Our cryogen-free Dewar integrates with a commercial electro-magnet and bridge. A description of the cryogenic and RF systems is given, along with the adaptations to the standard EPR experiment for operation at sub-Kelvin temperatures. As a first experiment, the EPR spectra of powdered Cr 12 O 9 (OH) 3 [Formula: see text] were measured. The sub-Kelvin EPR spectra agree well with predictions, and the performance of the sub-Kelvin system at 5K is compared to that of a commercial spectrometer. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  16. EPR investigation of some gamma-irradiated medicines

    International Nuclear Information System (INIS)

    Aleksieva, Katerina; Yordanov, Nicola

    2016-01-01

    The results of EPR studies on three medical tablets – Galanthamine, Cytisine and Tribulus terrestris before and after gamma-irradiation are reported. Before irradiation Galanthamine and Cytisine tablets are EPR silent, whereas Tribulus terrestris show a broad singlet line with g factor 2.2084±0.002. The same spectrum is recorded after irradiation. After gamma-sterilization, however, Galanthamine and Cytisine tablets exhibit a typical EPR spectrum due to gamma induced free radicals in lactose used as an excipient. These stable free radicals can be used for identification of radiation processing for a long time after it. Key words: medical tablets, gamma-irradiation, EPR

  17. 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.

  18. Nitrosyl hemoglobins: EPR above 80 K

    International Nuclear Information System (INIS)

    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

  19. US progress on the development of CR-39 based neutron dosimeters

    International Nuclear Information System (INIS)

    Hadlock, D.E.

    1987-06-01

    Historically at US nuclear facilities, two types of personnel neutron dosimeters have been in routine use: nuclear track emulsion-Type A (NTA) film and thermoluminescent dosimeter (TLD)-albedo. Both of these dosimeters have energy-dependent responses. Therefore, the neutron energy spectra must be known, to interpret the dosimeter results properly. A new state-of-the-art dosimetry system has been developed within the US Department of Energy (US DOE) Personnel Neutron Dosimeter Evaluation and Upgrade Program. This system is called the combination thermoluminescent dosimeter/track etch dosimeter (TLD/TED). This paper briefly describes US DOE research currently being conducted to further enhance the TED portion of the combination TLD/TED system. The research areas involved include dose sensitivity, neutron energy range, specialized radiators, self-developing dosimeters, and neutron spectrometry. 1 fig., 1 tab

  20. X-rays individual dose assessment using TLD dosimeters

    International Nuclear Information System (INIS)

    Salas, Carlos

    2008-01-01

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

  1. Use of spin traps to detect superoxide production in living cells by electron paramagnetic resonance (EPR) spectroscopy.

    Science.gov (United States)

    Abbas, Kahina; Babić, Nikola; Peyrot, Fabienne

    2016-10-15

    Detection of superoxide produced by living cells has been an on-going challenge in biology for over forty years. Various methods have been proposed to address this issue, among which spin trapping with cyclic nitrones coupled to EPR spectroscopy, the gold standard for detection of radicals. This technique is based on the nucleophilic addition of superoxide to a diamagnetic cyclic nitrone, referred to as the spin trap, and the formation of a spin adduct, i.e. a persistent radical with a characteristic EPR spectrum. The first application of spin trapping to living cells dates back 1979. Since then, considerable improvements of the method have been achieved both in the structures of the spin traps, the EPR methodology, and the design of the experiments including appropriate controls. Here, we will concentrate on technical aspects of the spin trapping/EPR technique, delineating recent breakthroughs, inherent limitations, and potential artifacts. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Retrospective individual dosimetry using EPR of tooth enamel

    International Nuclear Information System (INIS)

    Skvortzo, V.; Ivannikov, A.; Stepanenko, V.; Wieser, A.; Bougai, A.; Brick, A.; Chumak, V.; Radchuk, V.; Repin, V.; Kirilov, V.

    1996-01-01

    The results of joint investigations (in the framework of ECP-10 program) aimed on the improvement of the sensitivity and accuracy of the procedure of dose measurement using tooth enamel EPR spectroscopy are presented. It is shown, what the sensitivity of method may be increased using special physical-chemical procedure of the enamel samples treatment, which leads to the reducing of EPR signal of organic components in enamel. Tooth diseases may have an effect on radiation sensitivity of enamel. On the basis of statistical analysis of the results of more then 2000 tooth enamel samples measurements it was shown, what tooth enamel EPR spectroscopy gives opportunity to register contribution into total dose, which is caused by natural environmental radiation and by radioactive contamination. EPR response of enamel to ultraviolet exposure is investigated and possible influences to EPR dosimetry is discussed. The correction factors for EPR dosimetry in real radiation fields are estimated

  3. An Emergency Dosimeter for Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Braun, J; Nilsson, R

    1960-05-15

    A neutron dosimeter suitable for single emergency exposures is described. The dosimeter is furnished with detectors for thermal, epi-thermal and fast neutrons. This means that three of the constants by which the spectrum of the incident neutron flux is approximated, can be determined. The dose calculated from these approximated spectra is compared to the dose from spectra obtained in different standard spectra of types which may be expected in a radiation accident.

  4. Review of Fricke gel dosimeters

    International Nuclear Information System (INIS)

    Schreiner, L J

    2004-01-01

    The innovation of adding a gel matrix to the traditional Fricke dosimeter to stabilize geometric information established the field of gel dosimetry for radiation therapy. A discussion of Fricke gels provides an overview of the issues that determine the dose response of all gel dosimeters in general. In this paper we review some of the features of Fricke systems to illustrate these issues and, in addition, to motivate renewed clinical interest in Fricke gels

  5. Fiber-optic dosimeters for radiation therapy

    Science.gov (United States)

    Li, Enbang; Archer, James

    2017-10-01

    According to the figures provided by the World Health Organization, cancer is a leading cause of death worldwide, accounting for 8.8 million deaths in 2015. Radiation therapy, which uses x-rays to destroy or injure cancer cells, has become one of the most important modalities to treat the primary cancer or advanced cancer. The newly developed microbeam radiation therapy (MRT), which uses highly collimated, quasi-parallel arrays of x-ray microbeams (typically 50 μm wide and separated by 400 μm) produced by synchrotron sources, represents a new paradigm in radiotherapy and has shown great promise in pre-clinical studies on different animal models. Measurements of the absorbed dose distribution of microbeams are vitally important for clinical acceptance of MRT and for developing quality assurance systems for MRT, hence are a challenging and important task for radiation dosimetry. On the other hand, during the traditional LINAC based radiotherapy and breast cancer brachytherapy, skin dose measurements and treatment planning also require a high spatial resolution, tissue equivalent, on-line dosimeter that is both economical and highly reliable. Such a dosimeter currently does not exist and remains a challenge in the development of radiation dosimetry. High resolution, water equivalent, optical and passive x-ray dosimeters have been developed and constructed by using plastic scintillators and optical fibers. The dosimeters have peak edge-on spatial resolutions ranging from 50 to 500 microns in one dimension, with a 10 micron resolution dosimeter under development. The developed fiber-optic dosimeters have been test with both LINAC and synchrotron x-ray beams. This work demonstrates that water-equivalent and high spatial resolution radiation detection can be achieved with scintillators and optical fiber systems. Among other advantages, the developed fiber-optic probes are also passive, energy independent, and radiation hard.

  6. Investigation of anisotropy in EPR spectra of radiation defects in irradiated beryllium ceramics

    International Nuclear Information System (INIS)

    Polyakov, A.I.; Ryabikin, Yu.A.; Zashkvara, O. V.; Bitenbaev, M.I.; Petukhov, Yu. V.

    2004-01-01

    Full text: In this work results of analysis of anisotropy and hyperfine structure in EPR spectra of paramagnetic defects in irradiated samples of beryllium ceramics are presented. To explain peculiarities in a shape and parameters of the EPR spectrum hyperfine structure in beryllium ceramics, we have analyzed several versions of model representations for the radiation-induced paramagnetic defects uniformly distributed in a sample as well as for cluster defects which hyperfine structure is determined by interactions between electrons and nuclei of impurity atoms (S=1/2) and which are characterized by anisotropy in the g factors. Calculations of a shape of the uniformly widened EPR spectra are carried out by the model of random interactions between electron spins. The EPR spectra, widened at the expense of anisotropy in the g factors, are calculated by the following equation: g(Δ)=[2(ω-ω 0 )+α] -1/2 , where ω 0 =γH 0 , α is the quantify proportional to the anisotropy shift. To describe wings of spectral lines, where the equation doesn't work, we use the Gaussian function. To determine the frequency of precession of electron spins packages with local concentration N loc , the following expression is used: ω=ω 0 +1/2α(3cos 2 θ-1), where θ is an angle between the symmetry axis and the direction of the external magnetic field. It is shown that the best agreement between the calculated and experimental EPR spectra is observed with the following computational model: paramagnetic radiation defects are distributed uniformly over a ceramics sample, and the g factors of its EPR spectra have the anisotropy typical for dipole-dipole interaction in powder samples. By results of the data we obtained, it's clear that in future we'll need in more detailed information than that published in scientific journals about formation of the paramagnetic defect EPR spectra structure in beryllium oxides and ceramics at the expense of resonance line hyperfine splitting on atoms of

  7. Investigation of anisotropy in EPR spectra of radiation defects in irradiated beryllium ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Polyakov, A I; Ryabikin, Yu A; Zashkvara, O V; Bitenbaev, M I; Petukhov, Yu V [Inst. of Physics and Technology, Almaty (Kazakhstan)

    2004-07-01

    Full text: In this work results of analysis of anisotropy and hyperfine structure in EPR spectra of paramagnetic defects in irradiated samples of beryllium ceramics are presented. To explain peculiarities in a shape and parameters of the EPR spectrum hyperfine structure in beryllium ceramics, we have analyzed several versions of model representations for the radiation-induced paramagnetic defects uniformly distributed in a sample as well as for cluster defects which hyperfine structure is determined by interactions between electrons and nuclei of impurity atoms (S=1/2) and which are characterized by anisotropy in the g factors. Calculations of a shape of the uniformly widened EPR spectra are carried out by the model of random interactions between electron spins. The EPR spectra, widened at the expense of anisotropy in the g factors, are calculated by the following equation: g({delta})=[2({omega}-{omega}{sub 0})+{alpha}]{sup -1/2}, where {omega}{sub 0}={gamma}H{sub 0}, {alpha} is the quantify proportional to the anisotropy shift. To describe wings of spectral lines, where the equation doesn't work, we use the Gaussian function. To determine the frequency of precession of electron spins packages with local concentration N{sub loc}, the following expression is used: {omega}={omega}{sub 0}+1/2{alpha}(3cos{sup 2}{theta}-1), where {theta} is an angle between the symmetry axis and the direction of the external magnetic field. It is shown that the best agreement between the calculated and experimental EPR spectra is observed with the following computational model: paramagnetic radiation defects are distributed uniformly over a ceramics sample, and the g factors of its EPR spectra have the anisotropy typical for dipole-dipole interaction in powder samples. By results of the data we obtained, it's clear that in future we'll need in more detailed information than that published in scientific journals about formation of the paramagnetic defect EPR spectra structure in

  8. EPR assessment of the free radicals in irradiated foodstuffs

    International Nuclear Information System (INIS)

    Tencheva, S.; Katsareva, Ts.; Malinovski, A.; Kabasanov, K.

    1985-01-01

    In the hygienic assessment of radiation treated foodstuffs the study of free radicals formed during radiation exposure, their concentration and disintegration kinetics are of particular interest. In the work presented the concentration of the free radicals in irradiated prunes, nuts and corn is determined using EPR spectroscopy. The following doses are applied: 2, 10 and 20 kGy for prunes, 1, 10 and 20 kGy for nuts, and 0.75, 10 and 20 kGy for corn. EPR measurements are done immediately after the irradiation: 24 hours, and 3, 6, 9 and 15 days after the exposure. In the small radiation doses the formation of single radicals is observed. In doses of 10 kGy the spectra get complicated with the occurence of radicals R 1 , R 2 , R 3 and R 4 . The assessment of radicals proves to be a prospective method for the identification and determination of the preservation terms of foodstuffs

  9. Silicon Diode Dosimeter for Fast Neutrons

    International Nuclear Information System (INIS)

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

    1968-11-01

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

  10. Silicon Diode Dosimeter for Fast Neutrons

    Energy Technology Data Exchange (ETDEWEB)

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

    1968-11-15

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

  11. 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 2.5-10.0nm. It was proposed more than 30years ago, and nowadays is widely used in biophysics and materials science. Until recently, PD EPR experiments were limited to cryogenic temperatures (TEPR as well as other approaches based on EPR (e.g., 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. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Investigation of self-indicating radiation personal dosimeter

    International Nuclear Information System (INIS)

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

    2014-01-01

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

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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. - Highlights: • The EPR analysis of juices, nectars and syrups proves that the sample has been irradiated. • Two sample preparation procedures were used. • The stability of the radiation induced EPR signals was studied over 2 months. • Application of European standards can be extended for irradiated juices and syrups

  14. Clinical dosimeter based on diamond detector

    International Nuclear Information System (INIS)

    Chervjakov, A.M.; Ljalina, L.I.; Ljutina, G.J.; Khrunov, V.S.; Martynov, S.S.; Popov, S.A.

    2002-01-01

    Full text: Diamond detectors have found application in the relative dosimetry and their parameters have been described elsewhere. Today, the exclusive producer of the diamond detector is the Institute of Physical and Technical Problems, Russia, and exclusive dealer is the PTW-Freiburg. The main features of the diamond detector are good long time stability, suitable range of the energy dependence for photon and electron beams in clinical use, independence of the measured date from temperature and pressure. The high sensitivity per volume unit of the diamond detector (1500 times higher than ionization chamber) allowed using detectors with very small volume (1-5 mm 3 ) and rather simple electronics for ionization current registration. The new dosimeter consists of the diamond detector itself, 40 m registration cable, pre-amplifier, micro-processor block for data handling and absorbed dose calculation using the calibration factor of diamond detector in terms of absorbed dose to water. Dosimeter has the possibility to work with PC using standard RS-232 interface. The main features of the dosimeter are as follows: the range of dose rate measurements for photon, electron and proton beams is within 0.01-1.0 Gy/s; the energy ranges for photons are 0.08-25 MeV, and 4-25 MeV for electrons, with energy dependence no more than ±2%; the main uncertainty of the dose measurements is within ±2%; the pre-irradiation dose for diamond detector is no more than 10 Gy; the sensitive volume of the used diamond detectors is within 1-5 mm 3 ; the weight of the dosimeter no more than 2 kg. The new dosimeter was evaluated at the Central Research Institute of Roentgenology and Radiology, St. Petersburg, Russia to verify its performance. The dosimeter was used as a reference instrument for dose measurements at Cobalt-60 unit, SL75-5 and SL-20 linear accelerators and the test results have shown that the device have met the specifications. It is planned to produce dosimeter as serial device by

  15. Procedure for the delivering of personal short-term visitor dosimeters

    CERN Document Server

    2016-01-01

    Update of the administrative procedure for delivering a personal short-term visitor dosimeter to associated members of CERN’s personnel.   Associated members of the CERN personnel may request a short term visitor dosimeter if working only in Supervised Radiation Areas and for a period of less than two months in a calendar year. Such a dosimeter is delivered without the need to provide the usual regular documents: radiation passport, certificate from the home institute or medical certificate. Periodic verification will ensure that holders of these personal dosimeters do not exceed the maximum allowed personal dose for this type of dosimeter, which is the same as the limit for members of the public at 1 mSv per year. From now on, the two-month period can be spread over a calendar year, offering greater flexibility to users coming to CERN for multiple short periods. Please return unused dosimeters Persons leaving CERN for a period of more than one month should return their dosimeter to the D...

  16. Two-dimensional 220 MHz Fourier transform EPR imaging

    International Nuclear Information System (INIS)

    Placidi, Giuseppe; Brivati, John A.; Alecci, Marcello; Testa, Luca; Sotgiu, Antonello

    1998-01-01

    In the last decade radiofrequency continuous-wave EPR spectrometers have been developed to detect and localize free radicals in vivo. Only recently, pulsed radiofrequency EPR spectrometers have been described for imaging applications with small samples. In the present work, we show the first two-dimensional image obtained at 220 MHz on a large phantom (40 ml) that simulates typical conditions of in vivo EPR imaging. This pulsed EPR apparatus has the potential to make the time required for three-dimensional imaging compatible with the biological half-life of normally used paramagnetic probes. (author)

  17. Dose intercomparison study involving Fricke, ethanol chlorobenzene, PMMA and alanine dosimeters

    International Nuclear Information System (INIS)

    Lanuza, L.G.; Cabalfin, E.G.; Kojima, T.; Tachibana, H.

    1999-01-01

    A dose intercomparison study was carried out between the Philippine Nuclear Research Institute (PNRI) and Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute (JAERI) to determine reliability of the dosimetry systems being used by PNRI employing ethanol chlorobenzene (ECB), Fricke and alanine dosimeters. The Fricke and ECB dosimeters were prepared at PNRI while the alanine-polystyrene dosimeter was provided by JAERI. Fricke or ECB dosimeters were irradiated together with alanine at PNRI gamma irradiation facilities. Analyses of the Fricke and ECB dosimeters were performed at PNRI while alanine dosimeters were analyzed at JAERI. A comparison study between alanine and polymethylmethacrylate (PMMA, Radix RN15) dosimeters was also undertaken at JAERI. The dosimeters were irradiated together under different irradiation conditions using the gamma irradiation facilities of JAERI and Radia Industry Co. Ltd. (Japan). Evaluations of PMMA and alanine dosimeters were both performed at JAERI. Result of the dose intercomparison of PNRI with the International Atomic Energy Agency through the International Dose Assurance Service (IDAS) is also presented. (author)

  18. Dose intercomparison study involving Fricke, ethanol chlorobenzene, PMMA and alanine dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Lanuza, L G; Cabalfin, E G [Philippine Nuclear Research Institute, Quezon City (Philippines); Kojima, T; Tachibana, H [Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research institute, Takasaki (Japan)

    1999-03-01

    A dose intercomparison study was carried out between the Philippine Nuclear Research Institute (PNRI) and Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute (JAERI) to determine reliability of the dosimetry systems being used by PNRI employing ethanol chlorobenzene (ECB), Fricke and alanine dosimeters. The Fricke and ECB dosimeters were prepared at PNRI while the alanine-polystyrene dosimeter was provided by JAERI. Fricke or ECB dosimeters were irradiated together with alanine at PNRI gamma irradiation facilities. Analyses of the Fricke and ECB dosimeters were performed at PNRI while alanine dosimeters were analyzed at JAERI. A comparison study between alanine and polymethylmethacrylate (PMMA, Radix RN15) dosimeters was also undertaken at JAERI. The dosimeters were irradiated together under different irradiation conditions using the gamma irradiation facilities of JAERI and Radia Industry Co. Ltd. (Japan). Evaluations of PMMA and alanine dosimeters were both performed at JAERI. Result of the dose intercomparison of PNRI with the International Atomic Energy Agency through the International Dose Assurance Service (IDAS) is also presented. (author) 8 refs, 3 figs, 4 tabs

  19. EPR design features to mitigate severe accident challenges

    International Nuclear Information System (INIS)

    Mazurkiewicz, S.M.; Fischer, M.; Bittermann, D.

    2005-01-01

    The EPR, an evolutionary pressurized water reactor (PWR), is a 4300-4500 MWth that incorporates proven technology within an optimized configuration to enhance safety. EPR was originally developed through a joint effort between Framatome ANP and Siemens by incorporating the best technological features from the French and German nuclear reactor fleets into a cost-competitive product. Commercial EPR units are currently being built in Finland at the Olkiluoto site, and planned for France at the Flamanville site. In recent months, Framatome ANP announced their intention to market the EPR units to China in response to a request for vendor bids as well as their intent to pursue design certification in the United States under 10CFR52. The EPR safety philosophy is based on a deterministic consideration of defense-in-depth complemented by probabilistic analyses. Not only is the EPR designed to prevent and mitigate design basis accidents (DBAs), it employs an extra level of safety associated with severe accident response. Therefore, as a design objective, features are included to ensure that radiological consequences are limited such that the need for stringent counter measures, such as evacuation and relocation of the nearby population, can be reasonably excluded. This paper discusses some of the innovative features of the EPR to address severe accident challenges. (author)

  20. CVD diamond detectors and dosimeters

    International Nuclear Information System (INIS)

    Manfredotti, C.; Fizzotti, F.; LoGiudice, A.; Paolini, C.; Oliviero, P.; Vittone, E.; Torino Univ., Torino

    2002-01-01

    Natural diamond, because of its well-known properties of tissue-equivalence, has recorded a wide spreading use in radiotherapy planning with electron linear accelerators. Artificial diamond dosimeters, as obtained by Chemical Vapour Deposition (CVD) could be capable to offer the same performances and they can be prepared in different volumes and shapes. The dosimeter sensitivity per unit volume may be easily proved to be better than standard ionization microchamber. We have prepared in our laboratory CVD diamond microchamber (diamond tips) in emispherical shape with an external diameter of 200 μm, which can be used both as X-ray beam profilometers and as microdosimeters for small field applications like stereotaxy and also for in vivo applications. These dosimeters, which are obtained on a wire substrate that could be either metallic or SiC or even graphite, display good performances also as ion or synchrotron X-rays detectors

  1. 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.

  2. SO4--SO3- radical pair formation in Ce doped and Ce, U co-doped K3Na(SO4)2: EPR evidence and its role in TSL

    International Nuclear Information System (INIS)

    Natarajan, V.; Seshagiri, T.K.; Kadam, R.M.; Sastry, M.D.

    2002-01-01

    Thermally stimulated luminescence (TSL) and electron paramagnetic resonance (EPR) studies were carried out on cerium doped and cerium-uranium co-doped K 3 Na(SO 4 ) 2 samples after γ-irradiation. Three glow peaks around 352, 415 and 475 K were observed and their spectral characteristics have shown that Ce 3+ and UO 2 2+ act as the emission centres in K 3 Na(SO 4 ) 2 :Ce and K 3 Na(SO 4 ) 2 :Ce, U, respectively. In Ce-U co-doped sample, energy transfer from cerium to uranium takes place. The commonly occurring radiation-induced centres in sulphates, viz SO 3 - and SO 4 - were observed by EPR and SO 4 - radical ion was found to take part in the TSL emission at 415 K. The hitherto unknown information, however, is the formation of SO 4 - -SO 3 - radical pair creating deep traps in these lattices, apparently assisted by the dopants. This is the first observation of such radical pair formation leading to the identification of deep traps in this lattice. The radical pair, (SO 3 - -SO 4 - ) which is stable up to 970 K, decreases the intensity of the peak at 415 K due to the depletion of SO 4 - centres

  3. Calibration of dosimeters at 80-120 keV electron irradiation

    DEFF Research Database (Denmark)

    Miller, A.; Helt-Hansen, J.

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

  4. Evaluation of optical fibres as gamma radiation dosimeter

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  5. Characterization of high-sensitivity metal oxide semiconductor field effect transistor dosimeters system and LiF:Mg,Cu,P thermoluminescence dosimeters for use in diagnostic radiology

    International Nuclear Information System (INIS)

    Dong, S.L.; Chu, T.C.; Lan, G.Y.; Wu, T.H.; Lin, Y.C.; Lee, J.S.

    2002-01-01

    Monitoring radiation exposure during diagnostic radiographic procedures has recently become an area of interest. In recent years, the LiF:Mg,Cu,P thermoluminescence dosimeter (TLD-100H) and the highly sensitive metal oxide semiconductor field effect transistor (MOSFET) dosimeter were introduced as good candidates for entrance skin dose measurements in diagnostic radiology. In the present study, the TLD-100H and the MOSFET dosimeters were evaluated for sensitivity, linearity, energy, angular dependence, and post-exposure response. Our results indicate that the TLD-100H dosimeter has excellent linearity within diagnostic energy ranges and its sensitivity variations were under 3% at tube potentials from 40 Vp to 125 kVp. Good linearity was also observed with the MOSFET dosimeter, but in low-dose regions the values are less reliable and were found to be a function of the tube potentials. Both dosimeters also presented predictable angular dependence in this study. Our findings suggest that the TLD-100H dosimeter is more appropriate for low-dose diagnostic procedures such as chest and skull projections. The MOSFET dosimeter system is valuable for entrance skin dose measurement with lumbar spine projections and certain fluoroscopic procedures

  6. EPR by Areva. The path of greatest certainty

    International Nuclear Information System (INIS)

    2008-01-01

    AREVA's Evolutionary Power Reactor (EPR) is the first Generation III+ reactor design currently being built to answer the world's growing demand for clean and reliable electricity generation. Already under construction in Finland, France and China, the EPR is also being considered by America, United Kingdom, South Africa and other countries for the development of their nuclear fleet. The EPR is now clearly destined to become the mainstay of standardized, efficient reactor fleets around the globe. AREVA's EPR incorporates unbeatable know-how provided by an uninterrupted track record of reactor building activities and backed by decades of feedback experience from operating PWRs, including the most recent. The EPR is a Franco-German initiative which benefited from the stringent scrutiny of safety authorities from both countries, at each stage of the project. The EPR has already secured construction licenses from two of the world's most demanding safety authorities in France and Finland and is currently in line for a design certification and a combined construction and operating license (COL) in the USA. It is also taking part in the licensing process recently launched in the United Kingdom. Europe's leading utilities have granted the EPR their approval under the 'European Utilities Requirements' and have further expressed individual interest in the design and performance of the EPR for their businesses. AREVA is the only Gen III+ reactor constructor in the world with ongoing building experience. To date, AREVA is the only vendor who has the necessary field experience that future customers can benefit: - Detailed design completed; - Experience feedback from 87 PWR; - 3 projects going on; - Continuous PWR experience in design and construction. Close to 100% of the EPR primary circuit heavy components are sourced directly from AREVA's integrated plants. Engineering, manufacturing, services and fuel cycle management are totally integrated and mastered by AREVA. From its

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

    International Nuclear Information System (INIS)

    Aleksieva, K.; Georgieva, L.; Tzvetkova, E.; Yordanov, N.D.

    2009-01-01

    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 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.

  8. 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.

  9. EPR paradox revisited

    Energy Technology Data Exchange (ETDEWEB)

    Klippert, R. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)

    1999-07-01

    In a seminal paper from 1935 Einstein, Podolsky and Rosen produced one of the most powerful weapon against the unpredictability of the world ensured by quantum mechanics. The recent production of entangled states, with all its possible future applications in quantum computation, re-open the possibility of testing EPR states on physical grounds. The present intends to present a challenge to the wedding of classical (special) relativity with quantum mechanics, the so called relativistic quantum mechanics. Making use of the same apparatus devised in EPR, it is shown that non local quantum states are incompatible with either their possibility of being measured or else with Lorentz invariance (or even with both). (author)

  10. Personnel ionizing radiation dosimeter

    International Nuclear Information System (INIS)

    Williams, R.A.

    1975-01-01

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

  11. Limitations of commonly used thick-element personal dosimeters

    International Nuclear Information System (INIS)

    Gupta, V.P.

    1983-01-01

    In the ANSI Standard N13.11, accepted in June 1982, radiation dose depths of 1.0 cm and 0.007 cm in tissue for protection dosimetry have been adopted for deep and shallow dose equivalent estimations respectively. This standard is presently used for a mandatory personnel dosimetry performance testing program in the United States. Estimation of shallow-dose equivalent using a two-element dosimeter is described under the guidelines of this standard and the dosimetry practices followed by most dosimeter processors. A mathematical formulation, correlating a dosimeter response and shallow-dose equivalent factors at different energies, is presented. Also, the performance of a two-element thermoluminescent dosimeter is examined and the shallow-dose equivalent response results, both for the beta particles and photons, are discussed

  12. 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)

  13. The EPR - technology for the 3rd Millennium

    International Nuclear Information System (INIS)

    Bernstrauch, O.

    2000-01-01

    The Basic Design of the European Pressurized Water Reactor (EPR) was completed 1997 , the Basic Design Optimization Phase 1998 and the Detailed Design Phase will start in the near future. With these milestones, a new generation of PWRs is moving forward. Most of all, this is another story of a successful Franco-German cooperation. It is a rundown of the history of the EPR, before a decision is made to launch the lead-unit construction. The EPR project was launched in 1992 by Nuclear Power International (NPI), a joint company of FRAMATOME and Siemens KWU, supported by EDF and nine German electric utilities. Each step of the development of the EPR was harmonized with the Nuclear Safety Authorities both in France and Germany to reach an early approval. The EPR integrates the latest technological advances, especially in safety and operational aspects and comprises more than 30 years operating experience. Thus, the EPR combines the qualities of its predecessors, the French N4 and the German Konvoi. Presently, Siemens KWU and FRAMATOME are preparing the detailed design phase and the following construction and commissioning phase. The decision to build an EPR is not yet made either by the German electric utilities or by EdF, but it will be expected within the next months as a strong statement to follow the nuclear way and to ensure the know-how transfer. (author)

  14. EPR spectroscopy for the detection of foods treated with ionising radiation

    International Nuclear Information System (INIS)

    Stachowicz, W.; Burlinska, G.; Michalik, J.; Dziedzic-Goclawska, A.; Ostrowski, K.

    1996-01-01

    The advantage of electron paramagnetic resonance spectroscopy (EPR or ESR) as a tool for the control of irradiated food lies in its sensitivity and accuracy. Ionising radiation produces, in irradiated materials, paramagnetic species of different kinds, i.e. radicals, radical-ions and paramagnetic centres, which can be measured by EPR but most of them are not stable enough to be used for the detection of irradiation. It is because radiation-induced paramagnetic species are thermodynamically less stable than surrounding molecules and take part in fast radiolytic reactions leading to the formation of final diamagnetic products that they are not detectable by the EPR method. Most of organic radicals produced by radiation in the liquid phase ae unstable but if the unpaired electron is incorporated into the complex polymeric system as in peptides and polysaccharides and is structurally isolated from the water, its stability is markedly increased. Since 1954 it is known that ionising radiation produces paramagnetic entities in biological materials, cells and tissues and some are stable enough to be observed by EPR spectroscopy at room temperature. The present paper describes and discusses that part of results obtained by this group during the period of ADMIT activity (1989-94) which are original and may be useful to those who will be working in the near future on the development of uniform control systems for the detection of irradiated food. The intention was to focus attention on these facts and data which influence the certainty of the detection in both positive and negative manner. (author)

  15. EPR spectral investigation of radiation-induced radicals of gallic acid.

    Science.gov (United States)

    Tuner, Hasan

    2017-11-01

    In the present work, spectroscopic features of the radiation-induced radicals of gallic acid compounds were investigated using electron paramagnetic resonance (EPR) spectroscopy. While un-irradiated samples presented no EPR signal, irradiated samples exhibited an EPR spectrum consisting of an intense resonance line at the center and weak lines on both sides. Detailed microwave saturation investigations were carried out to determine the origin of the experimental EPR lines. It is concluded that the two side lines of the triplet satellite originate from forbidden "spin-flip" transitions. The spectroscopic and structural features of the radiation-induced radicals were determined using EPR spectrum fittings. The experimental EPR spectra of the two gallic acid compounds were consistent with the calculated EPR spectroscopic features of the proposed radicals. It is concluded that the most probable radicals are the cyclohexadienyl-type, [Formula: see text] radicals for both compounds.

  16. Solid-state personal dosimeter using dose conversion algorithm

    International Nuclear Information System (INIS)

    Lee, B.J.; Lee, Wanno; Cho, Gyuseong; Chang, S.Y.; Rho, S.R.

    2003-01-01

    Solid-state personal dosimeters using semiconductor detectors have been widely used because of their simplicity and real time operation. In this paper, a personal dosimeter based on a silicon PIN photodiode has been optimally designed by the Monte Carlo method and also developed. For performance test, the developed dosimeter was irradiated within the energy range between 50 keV and 1.25 MeV, the exposure dose rate between 3 mR/h and 25 R/h. The thickness of 0.2 mm Cu and 1.0 mm Al was selected as an optimal filter by simulation results. For minimizing the non-linear sensitivity on energy, dose conversion algorithm was presented, which was able to consider pulse number as well as pulse amplitude related to absorbed energies. The sensitivities of dosimeters developed by the proposed algorithm and the conventional method were compared and analyzed in detail. When dose conversion algorithm was used, the linearity of sensitivity was better about 38%. This dosimeter will be used for above 65 keV within the relative response of ±10% to 137 Cs

  17. Experimental EPR-steering using Bell-local states

    Science.gov (United States)

    Saunders, D. J.; Jones, S. J.; Wiseman, H. M.; Pryde, G. J.

    2010-11-01

    The concept of `steering' was introduced in 1935 by Schrödinger as a generalization of the EPR (Einstein-Podolsky-Rosen) paradox. It has recently been formalized as a quantum-information task with arbitrary bipartite states and measurements, for which the existence of entanglement is necessary but not sufficient. Previous experiments in this area have been restricted to an approach that followed the original EPR argument in considering only two different measurement settings per side. Here we demonstrate experimentally that EPR-steering occurs for mixed entangled states that are Bell local (that is, that cannot possibly demonstrate Bell non-locality). Unlike the case of Bell inequalities, increasing the number of measurement settings beyond two-we use up to six-significantly increases the robustness of the EPR-steering phenomenon to noise.

  18. EPR by Areva. The path of greatest certainty

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    AREVA's Evolutionary Power Reactor (EPR) is the first Generation III+ reactor design currently being built to answer the world's growing demand for clean and reliable electricity generation. Already under construction in Finland, France and China, the EPR is also being considered by America, United Kingdom, South Africa and other countries for the development of their nuclear fleet. The EPR is now clearly destined to become the mainstay of standardized, efficient reactor fleets around the globe. AREVA's EPR incorporates unbeatable know-how provided by an uninterrupted track record of reactor building activities and backed by decades of feedback experience from operating PWRs, including the most recent. The EPR is a Franco-German initiative which benefited from the stringent scrutiny of safety authorities from both countries, at each stage of the project. The EPR has already secured construction licenses from two of the world's most demanding safety authorities in France and Finland and is currently in line for a design certification and a combined construction and operating license (COL) in the USA. It is also taking part in the licensing process recently launched in the United Kingdom. Europe's leading utilities have granted the EPR their approval under the 'European Utilities Requirements' and have further expressed individual interest in the design and performance of the EPR for their businesses. AREVA is the only Gen III+ reactor constructor in the world with ongoing building experience. To date, AREVA is the only vendor who has the necessary field experience that future customers can benefit: - Detailed design completed; - Experience feedback from 87 PWR; - 3 projects going on; - Continuous PWR experience in design and construction. Close to 100% of the EPR primary circuit heavy components are sourced directly from AREVA's integrated plants. Engineering, manufacturing, services and fuel cycle management are totally

  19. A PC based thin film dosimeter system

    DEFF Research Database (Denmark)

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

    2000-01-01

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

  20. Correlations between the particles in the EPR-paradox

    Energy Technology Data Exchange (ETDEWEB)

    Treder, H.J. (Akademie der Wissenschaften der DDR, Potsdam-Babelsberg. Einstein-Laboratorium fuer Theoretische Physik)

    1984-03-01

    The Einstein-Podolsky-Rosen 'gedanken-experiment' does not imply non-local interactions or an 'action-at-a-distance'. Contrary, the EPR proves the measurements at one particle does not have influences at canonical variables of the other particles if the quantum-mechanical commutation relations are true. But, the EPR implies correlations between the particles which come in by 'subjective knowledge'. These correlations are a priori informations about the relative motion or, complementarily, about the motion of the center of mass. The impression of an action-at-a-distance is produced by the use of usual particle coordinates in the EPR-arrangements. The discussion of the Einstein-Podolsky-Rosen 'gedanken-experiment' (EPR) has been going on over fifty years. Einstein, Podolsky, and Rosen formulated their famous paradox in 1935, and in the discussion between N. Bohr (1935, 1949) and Einstein (1936, 1948); A. Einstein (1948) made his point that the EPR implied an 'action-at-a-distance' for quantum-mechanical particles (without obvious classical interactions). His argument is the starting point for the recent discussion about EPR and causality (see A. Aspect 1981).

  1. EPR-technical codes - a common basis for the EPR

    International Nuclear Information System (INIS)

    Zaiss, W.; Appell, B.

    1997-01-01

    The design and construction of Nuclear Power Plants implies a full set of codes and standards to define the construction rules of components and equipment. Rules are existing and are currently implemented, respectively in France and Germany (mainly RCCs and KTA safety standards). In the frame of the EPR-project, the common objective requires an essential industrial work programme between engineers from both countries to elaborate a common set of codes and regulations. These new industrial rules are called the ETCs (EPR Technical Codes). In the hierarchy the ETCs are - in case of France - on the common level of basic safety rules (RFS), design and construction rules (RCC) and - in Germany - belonging to RSK guidelines and KTA safety standards. A set of six ETCs will be elaborated to cover: safety and process, mechanical components, electrical equipment, instrumentation and control, civil works, fire protection. (orig.)

  2. Organic liquids as ''activ media'' in a holographic ionizing radiation dosimeter

    International Nuclear Information System (INIS)

    Nicolau-Rebigan, S.

    1979-01-01

    Some types of organic liquids for using as activ media in a holographic ionizing radiation dosimeter are presented. One outlined the advantages of the holographic dosimeter comparatively with those of common used dosimeters. One presented the advantages of utilization of the organic liquids comparatively with another chemical systems used in a holographic ionizing radiation dosimeter. (author)

  3. A web-based database for EPR centers in semiconductors

    International Nuclear Information System (INIS)

    Umeda, T.; Hagiwara, S.; Katagiri, M.; Mizuochi, N.; Isoya, J.

    2006-01-01

    We develop a web-based database system for electron paramagnetic resonance (EPR) centers in semiconductors. This database is available to anyone at http://www.kc.tsukuba.ac.jp/div-media/epr/. It currently has more than 300 records of the spin-Hamiltonian parameters for major known EPR centers. One can upload own new records to the database or can use simulation tools powered by EPR-NMR(C). Here, we describe the features and objectives of this database, and mention some future plans

  4. High-frequency EPR on high-spin transition-metal sites

    NARCIS (Netherlands)

    Mathies, Guinevere

    2012-01-01

    The electronic structure of transition-metal sites can be probed by electron-paramagnetic-resonance (EPR) spectroscopy. The study of high-spin transition-metal sites benefits from EPR spectroscopy at frequencies higher than the standard 9.5 GHz. However, high-frequency EPR is a developing field. In

  5. Can EPR non-locality be geometrical?

    International Nuclear Information System (INIS)

    Ne'eman, Y.

    1995-01-01

    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

  6. Radiation measured for ISS-Expedition 12 with different dosimeters

    International Nuclear Information System (INIS)

    Zhou, D.; Semones, E.; Gaza, R.; Johnson, S.; Zapp, N.; Weyland, M.

    2007-01-01

    Radiation in low Earth orbit (LEO) is mainly from Galactic Cosmic Rays (GCR), solar energetic particles and particles in South Atlantic Anomaly (SAA). These particles' radiation impact to astronauts depends strongly on the particles' linear energy transfer (LET) and is dominated by high LET radiation. It is important to investigate the LET spectrum for the radiation field and the influence of radiation on astronauts. At present, the best active dosimeters used for all LET are the tissue equivalent proportional counter (TEPC) and silicon detectors; the best passive dosimeters are thermoluminescence dosimeters (TLDs) or optically stimulated luminescence dosimeters (OSLDs) for low LET and CR-39 plastic nuclear track detectors (PNTDs) for high LET. TEPC, CR-39 PNTDs, TLDs and OSLDs were used to investigate the radiation for space mission Expedition 12 (ISS-11S) in LEO. LET spectra and radiation quantities (fluence, absorbed dose, dose equivalent and quality factor) were measured for the mission with these different dosimeters. This paper introduces the operation principles for these dosimeters, describes the method to combine the results measured by CR-39 PNTDs and TLDs/OSLDs, presents the experimental LET spectra and the radiation quantities

  7. An approved personal dosimetry service based on an electronic dosimeter

    International Nuclear Information System (INIS)

    Marshall, T.O.; Bartlett, D.T.; Burgess, P.H.; Campbell, J.I.; Hill, C.E.; Pook, E.A.; Sandford, D.J.

    1991-01-01

    At the Second Conference on Radiation Protection and Dosimetry a paper was presented which, in part, announced the development of an electronic dosimeter to be undertaken in the UK by the National Radiological Protection Board (NRPB) and Siemens Plessey Controls Ltd. This dosimeter was to be of a standard suitable for use as the basis of an approved personal dosimetry service for photon and beta radiations. The project has progressed extremely well and dosimeters and readers are about to become commercially available. The system and the specification of the dosimeter are presented. The NRPB is in the process of applying for approval by the Health and Safety Executive (HSE) to operate as personal monitoring service based on this dosimeter. As part of the approval procedure the dosimeter is being type tested and is also undergoing an HSE performance test and wearer trials. The tests and the wearer trials are described and a summary of the results to date presented. The way in which the service will be organized and operated is described and a comparison is made between the running of the service and others based on passive dosimeters at NRPB

  8. Investigating On Colour Stability Conditions Of Postirradiation Radiochromic Film Dosimeter

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  9. EPR and development of quantum electronics

    International Nuclear Information System (INIS)

    Manenkov, A A

    2011-01-01

    A role of electron paramagnetic resonance in development of quantum electronics is discussed. Basic principles and history of masers are briefly described. Spin-levels of paramagnetic ions in crystals as a very suitable object for active media of solid-state masers (called as EPR-masers) and physical processes in EPR-masers (population inversion of energy states) are analyzed. This analysis demonstrates a significant role of relaxation processes in multi-level spin-systems for efficient maser action. In this context peculiarities of spin-lattice and spin-spin cross relaxation processes in multi-level systems are analyzed. Development of EPR-masers and their application in radioastronomy and far-space communication systems are briefly described.

  10. EPR spectral investigation of radiation-induced radicals of gallic acid

    Energy Technology Data Exchange (ETDEWEB)

    Tuner, Hasan [Balikesir University, Department of Physics, Faculty of Art and Science, Balikesir (Turkey)

    2017-11-15

    In the present work, spectroscopic features of the radiation-induced radicals of gallic acid compounds were investigated using electron paramagnetic resonance (EPR) spectroscopy. While un-irradiated samples presented no EPR signal, irradiated samples exhibited an EPR spectrum consisting of an intense resonance line at the center and weak lines on both sides. Detailed microwave saturation investigations were carried out to determine the origin of the experimental EPR lines. It is concluded that the two side lines of the triplet satellite originate from forbidden ''spin-flip'' transitions. The spectroscopic and structural features of the radiation-induced radicals were determined using EPR spectrum fittings. The experimental EPR spectra of the two gallic acid compounds were consistent with the calculated EPR spectroscopic features of the proposed radicals. It is concluded that the most probable radicals are the cyclohexadienyl-type, O(OH){sub 2}C{sub 6}H{sub 2}COOH radicals for both compounds. (orig.)

  11. Assessment of performance parameters for EPR dosimetry with tooth enamel

    International Nuclear Information System (INIS)

    Wieser, A.; Fattibene, P.; Shishkina, E.A.; Ivanov, D.V.; De Coste, V.; Guettler, A.; Onori, S.

    2008-01-01

    In the framework of a comparison between three laboratories, electron paramagnetic resonance (EPR) signal-to-dose response curves were measured for sets of 30 tooth enamel samples and the variance of EPR measurements in dependence on absorbed dose was evaluated, in nine combinations of laboratory of sample preparation and EPR evaluation, respectively. As a test for benchmarking of EPR evaluation, the parameters 'critical dose' and 'limit of detection' were proposed as performance parameters following definitions from chemical-metrology, and a model function was suggested for analytical formulation of the dependence of the variance of EPR measurement on absorbed dose. First estimates of limits of detection by weighted and unweighted fitting resulted in the range 101-552 and 67-561 mGy, respectively, and were generally larger with weighted than with unweighted fitting. Indication was found for the influence of methodology of sample preparation and applied EPR measurement parameters on performance of EPR dosimetry with tooth enamel

  12. EPR spectral investigation of radiation-induced radicals of gallic acid

    International Nuclear Information System (INIS)

    Tuner, Hasan

    2017-01-01

    In the present work, spectroscopic features of the radiation-induced radicals of gallic acid compounds were investigated using electron paramagnetic resonance (EPR) spectroscopy. While un-irradiated samples presented no EPR signal, irradiated samples exhibited an EPR spectrum consisting of an intense resonance line at the center and weak lines on both sides. Detailed microwave saturation investigations were carried out to determine the origin of the experimental EPR lines. It is concluded that the two side lines of the triplet satellite originate from forbidden ''spin-flip'' transitions. The spectroscopic and structural features of the radiation-induced radicals were determined using EPR spectrum fittings. The experimental EPR spectra of the two gallic acid compounds were consistent with the calculated EPR spectroscopic features of the proposed radicals. It is concluded that the most probable radicals are the cyclohexadienyl-type, O(OH) 2 C 6 H 2 COOH radicals for both compounds. (orig.)

  13. Costing the EPR Project Using the Real Options Method

    International Nuclear Information System (INIS)

    Epaulard, Anne; Gallon, Stephane

    2001-01-01

    Real options theory makes it possible to cost investments which offer flexibility but whose returns are uncertain, such as the construction in 2000 of an EPR prototype; this prototype will enable the European pressurised-water reactor (EPR) to be used to renew EDF's nuclear power stations in 2020 (flexibility) but its economic worth will then depend on the cost of the competing gas-fired power plants (uncertain return). Options theory shows that investing in EPR technology in 2000 provides sufficient flexibility in 2020 to be considered cost-effective, even though use of EPRs is unlikely by that date. The investment made in 2000 to develop EPR technology therefore actually plays the part of an option or, in other words, insurance (against the risk of high gas prices)

  14. SU-E-T-749: Thorough Calibration of MOSFET Dosimeters

    International Nuclear Information System (INIS)

    Plenkovich, D; Thomas, J

    2015-01-01

    Purpose: To improve the accuracy of the MOSFET calibration procedure by performing the measurement several times and calculating the average value of the calibration factor for various photon and electron energies. Methods: The output of three photon and six electron beams of Varian Trilogy linear accelerator SN 5878 was calibrated. Five reinforced standard sensitivity MOSFET dosimeters were placed in the calibration jig and connected to the Reader Module. As the backscatter material was used 7 cm of Virtual Water. The MOSFET dosimeters were covered with 1.5 cm thick bolus for the regular and SRS 6 MV beams, 3 cm bolus for 15 MV beam, 1.5 cm bolus for 6 MeV electron beam, and 2 cm bolus for the electron energies of 9, 12, 15, 18, and 22 MeV. The dosimeters were exposed to 100 MU, and the calibration factor was determined using the mobileMOSFET software. To improve the accuracy of calibration, this procedure was repeated ten times and the calibration factors were averaged. Results: As the number of calibrations was increasing the variability of calibration factors of different dosimeters was decreasing. After ten calibrations, the calibration factors for all five dosimeters were within 1% of one another for all energies, except 6 MV SRS photons and 6 MeV electrons, for which the variability was 2%. Conclusions: The described process results in calibration factors which are almost independent of modality or energy. Once calibrated, the dosimeters may be used for in-vivo dosimetry or for daily verification of the beam output. Measurement of the radiation dose under bolus and scatter to the eye are examples of frequent use of calibrated MOSFET dosimeters. The calibration factor determined for full build-up is used under these circumstances. To the best of our knowledge, such thorough procedure for calibrating MOSFET dosimeters has not been reported previously. Best Medical Canada provided MOSFET dosimeters for this project

  15. 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.)

  16. Development of bead-type radiophotoluminescence glass dosimeter applicable to various purposes

    International Nuclear Information System (INIS)

    Sato, F.; Toyota, Y.; Maki, D.; Zushi, N.; Kato, Y.; Yamamoto, T.; Iida, T.

    2013-01-01

    Bead-type radiophotoluminescence (RPL) glass dosimeters were well fabricated with a gas-particle jet flame system for glass melting-cooling process. A rod of silver-activated phosphate glass was pulverized into micrometer-size particles. Spherical glass particles were formed from the pulverized glass particles in the high-temperature jet flame owing to the surface tension of the glass material. Some groups of spherical glass particles were irradiated with X-rays and their RPL was demonstrably observed for their exposure to UV light. A flexible RPL glass sheet was also made of bead-type RPL glass dosimeters and was useful for radiation imaging. Bead-type RPL glass dosimeters are expected to be used for dose monitoring in highly radioactively-contaminated area. -- Highlights: ► We developed bead-type radiophotoluminescence glass dosimeters. ► Bead-type glass RPL dosimeters are satisfactorily used as radiation dosimeters. ► A flexible RPL glass sheet is made of bead-type RPL glass dosimeters

  17. Light scattering in optical CT scanning of Presage dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Y; Adamovics, J; Cheeseborough, J C; Chao, K S; Wuu, C S, E-mail: yx2010@columbia.ed

    2010-11-01

    The intensity of the scattered light from the Presage dosimeters was measured using a Thorlabs PM100D optical power meter (Thorlabs Inc, Newton, NJ) with an optical sensor of 1 mm diameter sensitive area. Five Presage dosimeters were made as cylinders of 15.2 cm, 10 cm, 4 cm diameters and irradiated with 6 MV photons using a Varian Clinac 2100EX. Each dosimeter was put into the scanning tank of an OCTOPUS' optical CT scanner (MGS Research Inc, Madison, CT) filled with a refractive index matching liquid. A laser diode was positioned at one side of the water tank to generate a stationary laser beam of 0.8 mm width. On the other side of the tank, an in-house manufactured positioning system was used to move the optical sensor in the direction perpendicular to the outgoing laser beam from the dosimeters at an increment of 1 mm. The amount of scattered photons was found to be more than 1% of the primary light signal within 2 mm from the laser beam but decreases sharply with increasing off-axis distance. The intensity of the scattered light increases with increasing light attenuations and/or absorptions in the dosimeters. The scattered light at the same off-axis distance was weaker for dosimeters of larger diameters and for larger detector-to-dosimeter distances. Methods for minimizing the effect of the light scattering in different types of optical CT scanners are discussed.

  18. 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

  19. EPR detection of foods preserved with ionizing radiation

    International Nuclear Information System (INIS)

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

    1998-01-01

    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 the 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 ( 60 Co) and 10 MeV electrons were observed

  20. EPR detection of foods preserved with ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    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 the 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 ({sup 60}Co) and 10 MeV electrons were observed.

  1. Design performances and chemistry program supporting the FA3/UK-EPR (TM) Activity Management: Experience and Modelling Balance

    International Nuclear Information System (INIS)

    Tigeras, A.; Bachet, M.; Bremmes, O.; Berger, M.; Clinard, M.H.; Jolivet, P.; Chahma, F.

    2012-01-01

    Several methodologies have been applied to evaluate the source term in the primary circuit and to define the appropriate chemistry conditioning for the EPR reactor. These methodologies are based on nuclear power plant (NPP) feedback experience, laboratory data and modelling considerations. It is concluded that the activity risks are understood and can be managed with EPR design options. A strategy for the chemical conditioning of the primary coolant has been defined through the specifications for 3 parameters: pH, Zn and H 2 whose target and limit values are based on NPP feedback, international experimental data from laboratory tests, theoretical studies and numerical simulations. The material inventory selected for the primary components will allow low dose rates and low crud formation despite the high power level of the EPR reactor

  2. Diffusion measurement in ferrous infused gel dosimeters

    International Nuclear Information System (INIS)

    Zahmatkesh, M. H.; Healy, B. J.

    2003-01-01

    Background: The compositions of Ferrous sulphate, Agarose and Xylenol orange dye and Ferrous sulphate, Gelatin and Xylenol orange dye in solution of distilled water and sulphuric acid are two tissue-equivalent gel dosimeters. Ionizing radiation causes oxidation of Fe 2+ ion to Fe 3+ ions which diffuse through the gel matrix and blur the image of absorbed dose over a period of hours after irradiation. Materials and methods: 25 m M sulphuric acid, 0.4 mm ferrous ammonium sulphate, 0.2 mm xylenol orange dye and 1% by weight agarose in distilled water named Agarose and Xylenol orange dye and 0.1 mm ferrous ammonium sulphate, 0.1 mm xylenol orange dye, 50 mm sulphuric acid and 5% by weight gelatin in distilled water named Gelatin and Xylenol orange dye are used as two gel dosimeters. All chemicals were supplied by Sigma Ald ridge Company, Germany. The gels were poured in Perspex casts and were irradiated to a beam of X ray from linear accelerators or X ray machine. Results: In this study diffusion coefficients of Agarose and Xylenol orange dye and Gelatin and Xylenol orange dye dosimeters have been measured through a computer program for different temperature. The ferric ion diffusion coefficient (D) for the Agarose and Xylenol orange dye and Gelatin and Xylenol orange dye dosimeters were measured as (1.19.±0.03) x 10 -2 cm 2 .hr -1 and (0.83±0.03) x 10 -2 cm 2 .hr -1 respectively at room temperature. Conclusion: For both dosimeters the diffusion coefficients decreased with gel storage temperatures down to 6 d ig C . Gelatin and Xylenol orange dye dosimeters have advantage of lower diffusion coefficient for a specified temperature

  3. Development and underground testing of the α dosimeter: a solid state electronic personal radiation dosimeter for uranium miners

    International Nuclear Information System (INIS)

    Parkinson, R.N.; Roze, V.; Shepherd, R.

    1981-01-01

    The αDOSIMETER is a complete, integrated system designed to monitor the immediate worksite of underground miners where the disintegration for radon daughters is a risk to the health of mining personnel. The dosimeter weighing little more than one pound is worn by each miner throughout the entire shift and is powered by the miner's cap lamp battery. After this integration period, the unit is connected to a reading network whereupon the day's data is dumped, calculated and stored. Beginning in July 1980, prototype units were subjected to vigorous underground testing in uranium mines in Canada and the United States and in tin mines in Cornwall, UK. The testing results are summarized and proposals advanced for a typical mine monitoring system utilizing the αDOSIMETER

  4. Site-specific calibration of the Hanford personnel neutron dosimeter

    International Nuclear Information System (INIS)

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

    1994-10-01

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

  5. Development of a new type thyroid glands dosimeter

    International Nuclear Information System (INIS)

    He Lihua; Song Yiyang; Chen Qin; Chen Yannan

    2000-01-01

    A new dosimeter of 125 I in thyroid gland is described. The dosimeter consists of NaI(Tl) detector and intelligent data recorder. Single-chip-microcomputer is used for data handling. The activity of 125 I in thyroid glands of human being is measured directly, rapidly, and accurately. Furthermore, it can calculate and display the intake, committed dose equivalent and committed effective dose equivalent. The measuring range of 125 I in thyroid glands is 10-2 x 10 6 Bq. The dosimeter has been operating continuously for a long time with high stability

  6. Device for the automatic evaluation of pencil dosimeters

    International Nuclear Information System (INIS)

    Schallopp, B.

    1976-01-01

    In connenction with the automation of radiation protection in nuclear power plants, an automatic reading device has been developed for the direct input of the readings of pencil dosimeters into a computer. Voltage measurements would be simple but are excluded, because the internal electrode of the dosimeter may not be touched, for operational reasons. This paper describes an optical/electronic conversion device in which the reading of the dosimeter is projected onto a Vidicon, scanned, and converted into a digital signal for output to the computer. (orig.) [de

  7. 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 T 1 -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 W n commonly used in the CW-EPR literature for 14 N-nitroxyl spin labels is inconsistent with that currently adopted in time-resolved EPR measurements of saturation recovery. Redefinition of the normalised 14 N spin-lattice relaxation rate, b=W n /(2W e ), 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 14 N-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 14 N-relaxation: T 1 n =1/W n . Results are compared and contrasted with those for the two-level 15 N-nitroxide system. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Portable battery-free charger for radiation dosimeters

    International Nuclear Information System (INIS)

    Manning, F.W.

    1984-01-01

    This invention is a novel portable charger for dosimeters of the electrometer type. The charger does not require batteries or piezoelectric crystals and is of rugged construction. In a preferred embodiment, the charge includes a housing which carries means for mounting a dosimeter to be charged. The housing also includes contact means for impressing a charging voltage across the mounted dosimeter. Also, the housing carries a trigger for operating a charging system mounted in the housing. The charging system includes a magnetic loop including a permanent magnet for establishing a magnetic field through the loop. A segment of the loop is coupled to the trigger for movement thereby to positions opening and closing the loop. A coil inductively coupled with the loop generates coil-generated voltage pulses when the trigger is operated to open and close the loop. The charging system includes an electrical circuit for impressing voltage pulses from the coil across a capacitor for integrating the pulses and applying the resulting integrated voltage across the above-mentioned contact means for charging the dosimeter

  9. Portable battery-free charger for radiation dosimeters

    Science.gov (United States)

    Manning, Frank W.

    1984-01-01

    This invention is a novel portable charger for dosimeters of the electrometer type. The charger does not require batteries or piezoelectric crystals and is of rugged construction. In a preferred embodiment, the charge includes a housing which carries means for mounting a dosimeter to be charged. The housing also includes contact means for impressing a charging voltage across the mounted dosimeter. Also, the housing carries a trigger for operating a charging system mounted in the housing. The charging system includes a magnetic loop including a permanent magnet for establishing a magnetic field through the loop. A segment of the loop is coupled to the trigger for movement thereby to positions opening and closing the loop. A coil inductively coupled with the loop generates coil-generated voltage pulses when the trigger is operated to open and close the loop. The charging system includes an electrical circuit for impressing voltage pulses from the coil across a capacitor for integrating the pulses and applying the resulting integrated voltage across the above-mentioned contact means for charging the dosimeter.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  11. Orientation-dependent effects of EPR-measurements on β-rhombohedral boron

    International Nuclear Information System (INIS)

    Siems, C.D.; Geist, D.

    1976-01-01

    EPR studies on β-rhombohedral boron have been reported by several authors. Two EPR-lines with the same g-value have been found by measurements with and without illumination. The microwave frequency used was 9 GHz, as far as is known. In this paper EPR-measurements at 35 GHz on β-rhombohedral boron single crystals are reported. The investigations concerning the 'dark EPR-line' were made at 300 K. (Auth.)

  12. Selective saturation method for EPR dosimetry with tooth enamel

    International Nuclear Information System (INIS)

    Ignatiev, E.A.; Romanyukha, A.A.; Koshta, A.A.; Wieser, A.

    1996-01-01

    The method of selective saturation is based on the difference in the microwave (mw) power dependence of the background and radiation induced EPR components of the tooth enamel spectrum. The subtraction of the EPR spectrum recorded at low mw power from that recorded at higher mw power provides a considerable reduction of the background component in the spectrum. The resolution of the EPR spectrum could be improved 10-fold, however simultaneously the signal-to-noise ratio was found to be reduced twice. A detailed comparative study of reference samples with known absorbed doses was performed to demonstrate the advantage of the method. The application of the selective saturation method for EPR dosimetry with tooth enamel reduced the lower limit of EPR dosimetry to about 100 mGy. (author)

  13. Identification of mitochondrial electron transport chain-mediated NADH radical formation by EPR spin-trapping techniques.

    Science.gov (United States)

    Matsuzaki, Satoshi; Kotake, Yashige; Humphries, Kenneth M

    2011-12-20

    The mitochondrial electron transport chain (ETC) is a major source of free radical production. However, due to the highly reactive nature of radical species and their short lifetimes, accurate detection and identification of these molecules in biological systems is challenging. The aim of this investigation was to determine the free radical species produced from the mitochondrial ETC by utilizing EPR spin-trapping techniques and the recently commercialized spin-trap, 5-(2,2-dimethyl-1,3-propoxycyclophosphoryl)-5-methyl-1-pyrroline N-oxide (CYPMPO). We demonstrate that this spin-trap has the preferential quality of having minimal mitochondrial toxicity at concentrations required for radical detection. In rat heart mitochondria and submitochondrial particles supplied with NADH, the major species detected under physiological pH was a carbon-centered radical adduct, indicated by markedly large hyperfine coupling constant with hydrogen (a(H) > 2.0 mT). In the presence of the ETC inhibitors, the carbon-centered radical formation was increased and exhibited NADH concentration dependency. The same carbon-centered radical could also be produced with the NAD biosynthesis precursor, nicotinamide mononucleotide, in the presence of a catalytic amount of NADH. The results support the conclusion that the observed species is a complex I derived NADH radical. The formation of the NADH radical could be blocked by hydroxyl radical scavengers but not SOD. In vitro experiments confirmed that an NADH-radical is readily formed by hydroxyl radical but not superoxide anion, further implicating hydroxyl radical as an upstream mediator of NADH radical production. These findings demonstrate the identification of a novel mitochondrial radical species with potential physiological significance and highlight the diverse mechanisms and sites of production within the ETC.

  14. Fast fluence measurement for JOYO irradiation field using niobium dosimeter

    International Nuclear Information System (INIS)

    Ito, Chikara

    2004-03-01

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

  15. CW EPR and 9 GHz EPR imaging investigation of stable paramagnetic species and their antioxidant activities in dry shiitake mushroom (Lentinus edodes).

    Science.gov (United States)

    Nakagawa, Kouichi; Hara, Hideyuki

    2016-01-01

    We investigated the antioxidant activities and locations of stable paramagnetic species in dry (or drying) shiitake mushroom (Lentinus edodes) using continuous wave (CW) electron paramagnetic resonance (EPR) and 9 GHz EPR imaging. CW 9 GHz EPR detected paramagnetic species (peak-to-peak linewidth (ΔHpp) = 0.57 mT) in the mushroom. Two-dimensional imaging of the sharp line using a 9 GHz EPR imager showed that the species were located in the cap and shortened stem portions of the mushroom. No other location of the species was found in the mushroom. However, radical locations and concentrations varied along the cap of the mushroom. The 9 GHz EPR imaging determined the exact location of stable paramagnetic species in the shiitake mushroom. Distilled water extracts of the pigmented cap surface and the inner cap of the mushroom showed similar antioxidant activities that reduced an aqueous solution of 0.1 mM 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl. The present results suggest that the antioxidant activities of the edible mushroom extracts are much weaker than those of ascorbic acid. Thus, CW EPR and EPR imaging revealed the location and distribution of stable paramagnetic species and the antioxidant activities in the shiitake mushroom for the first time.

  16. Relativistic Nonlocality and the EPR Paradox

    Science.gov (United States)

    Chamberlain, Thomas

    2014-03-01

    The exact violation of Bell's Inequalities is obtained with a local realistic model for spin. The model treats one particle that comprises a quantum ensemble and simulates the EPR data one coincidence at a time as a product state. Such a spin is represented by operators σx , iσy ,σz in its body frame rather than the usual set of σX ,σY ,σZ in the laboratory frame. This model, assumed valid in the absence of a measuring probe, contains both quantum polarizations and coherences. Each carries half the EPR correlation, but only half can be measured using coincidence techniques. The model further predicts the filter angles that maximize the spin correlation in EPR experiments.

  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

    International Nuclear Information System (INIS)

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

    2011-01-01

    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. 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.

  20. Laser readable thermoluminescent radiation dosimeters and methods for producing thereof

    International Nuclear Information System (INIS)

    Braunlich, P.F.; Tetzlaff, W.

    1989-01-01

    Thin layer thermoluminescent radiation dosimeters for use in laser readable dosimetry systems, and methods of fabricating such thin layer dosimeters are disclosed. The thin layer thermoluminescent radiation dosimeters include a thin substrate made from glass or other inorganic materials capable of withstanding high temperatures and high heating rates. A thin layer of a thermoluminescent phosphor material is heat bonded to the substrate using an inorganic binder such as glass. The dosimeters can be mounted in frames and cases for ease in handling. Methods of the invention include mixing a suitable phosphor composition and binder, both being in particulate or granular form. The mixture is then deposited onto a substrate such as by using mask printing techniques. The dosimeters are thereafter heated to fuse and bond the binder and phosphor to the substrate. 34 figs

  1. Energy response study of modified CR-39 neutron personnel dosimeter

    International Nuclear Information System (INIS)

    Sathian, Deepa; Bakshi, A.K.; Datta, D.; Nair, Sreejith S.; Sathian, V.; Mishra, Jitendra; Sen, Meghnath

    2018-01-01

    Personnel neutron dosimetry is an integral part of radiation protection. No single dosimeter provides the satisfactory energy response, sensitivity, angular dependence characteristics and accuracy necessary to meet the requirement of an ideal personnel neutron dosimeter. The response of a personnel neutron dosimeter is critically dependent upon the energy distribution of the neutron field. CR-39 personnel neutron dosimeters were typically calibrated in the standard neutron field of 252 Cf and 241 Am-Be in our laboratory, although actual neutron fields may vary from the calibration neutron spectrum. Recently the badge cassette of the personnel neutron dosimeter was changed due to frequent damage of the PVC badge used earlier. This paper discusses energy response of CR-39 solid state nuclear track detector loaded in this modified badge cassette as per latest ISO recommendation

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

    Science.gov (United States)

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

    2015-11-17

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

  3. EPR: Some History and Clarification

    Science.gov (United States)

    Fine, Arthur

    2002-04-01

    Locality, separation and entanglement 1930s style. We’ll explore the background to the 1935 paper by Einstein, Podolsky and Rosen, how it was composed, the actual argument of the paper, the principles used, and how the paper was received by Schroedinger, and others.We’ll also look at Bohr’s response: the extent to which Bohr connects with what Einstein was after in EPR and the extent to EPR marks a shift in Bohr’s thinking about the quantum theory.

  4. Chirp echo Fourier transform EPR-detected NMR.

    Science.gov (United States)

    Wili, Nino; Jeschke, Gunnar

    2018-04-01

    A new ultra-wide band (UWB) pulse EPR method is introduced for observing all nuclear frequencies of a paramagnetic center in a single shot. It is based on burning spectral holes with a high turning angle (HTA) pulse that excites forbidden transitions and subsequent detection of the hole pattern by a chirp echo. We term this method Chirp Echo Epr SpectroscopY (CHEESY)-detected NMR. The approach is a revival of FT EPR-detected NMR. It yields similar spectra and the same type of information as electron-electron double resonance (ELDOR)-detected NMR, but with a multiplex advantage. We apply CHEESY-detected NMR in Q band to nitroxides and correlate the hyperfine spectrum to the EPR spectrum by varying the frequency of the HTA pulse. Furthermore, a selective π pulse before the HTA pulse allows for detecting hyperfine sublevel correlations between transitions of one nucleus and for elucidating the coupling regime, the same information as revealed by the HYSCORE experiment. This is demonstrated on hexaaquamanganese(II). We expect that CHEESY-detected NMR is generally applicable to disordered systems and that our results further motivate the development of EPR spectrometers capable of coherent UWB excitation and detection, especially at higher fields and frequencies. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  5. Chirp echo Fourier transform EPR-detected NMR

    Science.gov (United States)

    Wili, Nino; Jeschke, Gunnar

    2018-04-01

    A new ultra-wide band (UWB) pulse EPR method is introduced for observing all nuclear frequencies of a paramagnetic center in a single shot. It is based on burning spectral holes with a high turning angle (HTA) pulse that excites forbidden transitions and subsequent detection of the hole pattern by a chirp echo. We term this method Chirp Echo Epr SpectroscopY (CHEESY)-detected NMR. The approach is a revival of FT EPR-detected NMR. It yields similar spectra and the same type of information as electron-electron double resonance (ELDOR)-detected NMR, but with a multiplex advantage. We apply CHEESY-detected NMR in Q band to nitroxides and correlate the hyperfine spectrum to the EPR spectrum by varying the frequency of the HTA pulse. Furthermore, a selective π pulse before the HTA pulse allows for detecting hyperfine sublevel correlations between transitions of one nucleus and for elucidating the coupling regime, the same information as revealed by the HYSCORE experiment. This is demonstrated on hexaaquamanganese(II). We expect that CHEESY-detected NMR is generally applicable to disordered systems and that our results further motivate the development of EPR spectrometers capable of coherent UWB excitation and detection, especially at higher fields and frequencies.

  6. Effect of electromagnetic field in fusion facility on electronic personal dosimeter

    International Nuclear Information System (INIS)

    Yamada, Junya; Kawano, Takao; Uda, Tatsuhiko; Shimo, Michikuni

    2010-01-01

    The effect of electromagnetic field on electronic personal dosimeters in a nuclear fusion facility was examined in a Magnetic Resonance Imaging (MRI) examination room instead of a nuclear fusion facility. Three types of electronic personal dosimeters, the PDM-111, the 112, and the 117, were used as typical ones. We surveyed the electromagnetic field distribution and dosimeters were placed at locations with various strengths of the electromagnetic field. The natural radiation dose was measured for about one week. We found that while dosimeters were not affected by the electric field, they were affected by the magnetic one. Dosimeters detected radiation levels less sensitively as the magnetic field strength was increased up to 150 mT. The dosimeters underestimated the environmental radiation dose rates by about 10-30% when the magnetic field strength was larger than 150 mT. We assumed that hall-effect caused the reduction in radiation sensitivity. We concluded that the strength of the magnetic field needs to be carefully considered when an electronic personal dosimeter is used for monitoring both personal and area dose in a nuclear fusion facility. (author)

  7. Spectrophotometric readout for an alanine dosimeter for food irradiation applications

    International Nuclear Information System (INIS)

    Ebraheem, S.; Beshir, W.B.; Eid, S.; Sobhy, R.; Kovacs, A.

    2003-01-01

    The alanine-electron spin resonance (EPR) readout system is well known as a reference and transfer dosimetry system for the evaluation of high doses in radiation processing. The high cost of an EPR/alanine dosimetry system is a serious handicap for large-scale routine application in irradiation facilities. In this study, the use of a complex produced by dissolving irradiated L-alanine in 1,4-phenyl diammonium dichloride solution was investigated for dosimetry purposes. This complex--having a purple colour--has an increasing absorbance with increasing dose in the range of 1-20 kGy. The applicability of spectrophotometric evaluation was studied by measuring the absorbance intensity of this complex at 360 and 505 nm, respectively. Fluorimetric evaluation was also investigated by measuring the emission of the complex at 435 nm as a function of dose. The present method is easy for routine application. The effect of the dye concentration as well as the suitable amount of irradiated alanine has been studied. With respect to routine application, the stability of the product complex after its formation was also investigated

  8. Scope and limitations of the TEMPO/EPR method for singlet oxygen detection: the misleading role of electron transfer.

    Science.gov (United States)

    Nardi, Giacomo; Manet, Ilse; Monti, Sandra; Miranda, Miguel A; Lhiaubet-Vallet, Virginie

    2014-12-01

    For many biological and biomedical studies, it is essential to detect the production of (1)O2 and quantify its production yield. Among the available methods, detection of the characteristic 1270-nm phosphorescence of singlet oxygen by time-resolved near-infrared (TRNIR) emission constitutes the most direct and unambiguous approach. An alternative indirect method is electron paramagnetic resonance (EPR) in combination with a singlet oxygen probe. This is based on the detection of the TEMPO free radical formed after oxidation of TEMP (2,2,6,6-tetramethylpiperidine) by singlet oxygen. Although the TEMPO/EPR method has been widely employed, it can produce misleading data. This is demonstrated by the present study, in which the quantum yields of singlet oxygen formation obtained by TRNIR emission and by the TEMPO/EPR method are compared for a set of well-known photosensitizers. The results reveal that the TEMPO/EPR method leads to significant overestimation of singlet oxygen yield when the singlet or triplet excited state of the photosensitizer is efficiently quenched by TEMP, acting as electron donor. In such case, generation of the TEMP(+) radical cation, followed by deprotonation and reaction with molecular oxygen, gives rise to an EPR-detectable TEMPO signal that is not associated with singlet oxygen production. This knowledge is essential for an appropriate and error-free application of the TEMPO/EPR method in chemical, biological, and medical studies. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. UVB DNA dosimeters analyzed by polymerase chain reactors

    International Nuclear Information System (INIS)

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

    1997-01-01

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

  10. A pocket warning γ-dosimeter with numerical display

    International Nuclear Information System (INIS)

    Jones, A.R.

    1980-09-01

    A pocket warning dosimeter is described. It provides alarms (continuous tone and a flashing red light) when a presettable dose has been accumulated in the range .064 - 16.4 rads (0.64 - 164 μGy). This warning level can be selected in nine steps of 2 with a switch inside the dosimeter. The dose rate is indicated by a series of sound pulses whose repetition rate is proportional to the dose rate. At 1 rad/h (10 mGy/h) about 17 pluses/minute are emitted. The accumulated dose up to 20 rads (0.2 Gy) is displayed in steps of 1 mrad (10 μGy) with a liquid crystal display. A red LED lights before battery failure occurs. The effects of changes in temperature, battery voltage, dose rate and photon energy upon dosimeter sensitivity are presented. Finally, the applications of the dosimeter are discussed. (auth)

  11. LOW-COST PERSONNEL DOSIMETER.

    Science.gov (United States)

    specification was achieved by simplifying and improving the basic Bendix dosimeter design, using plastics for component parts, minimizing direct labor, and making the instrument suitable for automated processing and assembly. (Author)

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

    International Nuclear Information System (INIS)

    Yordanov, N.D.; Aleksieva, K.

    2007-01-01

    The shape and time stability of the electron paramagnetic resonance (EPR) spectra of non- and γ-irradiated papaya, melon, cherry and fig samples dehydrated via osmosis are reported. It is shown that non-irradiated samples are generally EPR silent whereas γ-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

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

    Science.gov (United States)

    Yordanov, N. D.; Aleksieva, K.

    2007-06-01

    The shape and time stability of the electron paramagnetic resonance (EPR) spectra of non- and γ-irradiated papaya, melon, cherry and fig samples dehydrated via osmosis are reported. It is shown that non-irradiated samples are generally EPR silent whereas γ-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.

  14. Angular dependence of the nanoDot OSL dosimeter

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  15. Investigation of EPR signals on tooth enamel

    Energy Technology Data Exchange (ETDEWEB)

    Pavlenko, A; Mironova-Ulmane, N; Polakov, M; Riekstina, D [Institute of Solid State Physics, University of Latvia, Riga (Latvia)

    2007-12-15

    Calcified tissues are involved in continues metabolic process in human organism exchanging a number of chemical elements with environment. The rate of biochemical reactions is tissue dependent and the slowest one at the tooth enamel, the most mineralized tissue of human organism. The long time stability and unique chemical composition make tooth enamel suitable for number of application. The assessment of individual radiation dose by Electron Paramagnetic Resonance (EPR) and evaluations of elemental composition by Instrumentation Neutron Activation Analysis (INAA) are the well known procedures where properties of tooth enamel intensively used. The current work is focused on investigation of EPR signals and determination of chemical composition on several teeth samples having different origin. The EPR spectra and INAA element content of milk tooth, caries tooth, and paradantose tooth have been compared to each other. The results showed that the intensity of EPR signal is much higher for the caries tooth than the for paradantose tooth that is in agreement with depleted Ca content.

  16. Software for evaluation of EPR-dosimetry performance

    International Nuclear Information System (INIS)

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

    2014-01-01

    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. (authors)

  17. 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.

  18. Polymer gel dosimeter with AQUAJOINT® as hydrogel matrix

    Science.gov (United States)

    Maeyama, Takuya; Ishida, Yasuhiro; Kudo, Yoshihiro; Fukasaku, Kazuaki; Ishikawa, Kenichi L.; Fukunishi, Nobuhisa

    2018-05-01

    We report a polymer gel dosimeter based on a new gel matrix (AQUAJOINT®) that is a thermo-irreversible hydrogel formed by mixing two types of water-based liquids at room temperature. Normoxic N-vinylpyrrolidone-based polymer gels were prepared with AQUAJOINT® instead of gelatin. This AQUAJOINT®-based gel dosimeter exhibits a 2.5-fold increase in sensitivity over a gelatin-based gel dosimeter and a linear dose-response in the dose range of 0-8 Gy. This gel has heat resistance in a jar and controlled gel properties such as viscoelastic and mechanical characters, which may be useful for deformable polymer gel dosimetry.

  19. Dose response characteristics of polymethacrylic acid gel (PMAAG) for a polymerization-based dosimeter using NMR.

    Science.gov (United States)

    Iskandar, S M; Elias, S; Jumiah, H; Asri, M T M; Masrianis, A; Ab Rahman, M Z; Taiman, K; Abdul Rashid, M Y

    2004-05-01

    The radiation-response characteristics of polymetharylic acid gel dosimeter prepared with different concentrations of monomer and cross-linker is described in these studies. The dosimeters were prepared under the hypoxic condition in a glove box and were then irradiated with gamma-rays produced by Co-60 radionuclide that was generated at 1.25MeV energy. The irradiation took place at different doses ranged from 0Gy to 19Gy. Due to the radiation activities, chain-reaction polymerisation processes had taken place in the formation of polymethacrylic acid (PMAA) gel, which cause the dose response mechanism increased in the NMR relaxation rates of protons. It has been observed that for higher concentration of monomer and cross-linker, the polymerization rate was increased.

  20. Copper(II) Thiosemicarbazone Complexes and Their Proligands upon UVA Irradiation: An EPR and Spectrophotometric Steady-State Study.

    Science.gov (United States)

    Hricovíni, Michal; Mazúr, Milan; Sîrbu, Angela; Palamarciuc, Oleg; Arion, Vladimir B; Brezová, Vlasta

    2018-03-21

    X- and Q-band electron paramagnetic resonance (EPR) spectroscopy was used to characterize polycrystalline Cu(II) complexes that contained sodium 5-sulfonate salicylaldehyde thiosemicarbazones possessing a hydrogen, methyl, ethyl, or phenyl substituent at the terminal nitrogen. The ability of thiosemicarbazone proligands to generate superoxide radical anions and hydroxyl radicals upon their exposure to UVA irradiation in aerated aqueous solutions was evidenced by the EPR spin trapping technique. The UVA irradiation of proligands in neutral or alkaline solutions and dimethylsulfoxide (DMSO) caused a significant decrease in the absorption bands of aldimine and phenolic chromophores. Mixing of proligand solutions with the equimolar amount of copper(II) ions resulted in the formation of 1:1 Cu(II)-to-ligand complex, with the EPR and UV-Vis spectra fully compatible with those obtained for the dissolved Cu(II) thiosemicarbazone complexes. The formation of the complexes fully inhibited the photoinduced generation of reactive oxygen species, and only subtle changes were found in the electronic absorption spectra of the complexes in aqueous and DMSO solutions upon UVA steady-state irradiation. The dark redox activity of copper(II) complexes and proligand/Cu(II) aqueous solutions towards hydrogen peroxide which resulted in the generation of hydroxyl radicals, was confirmed by spin trapping experiments.

  1. Most advanced HTP fuel assembly design for EPR

    International Nuclear Information System (INIS)

    Francillon, Eric; Kiehlmann, Horst-Dieter

    2006-01-01

    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

  2. On the annealing of the EPR dislocation signal in silicon

    International Nuclear Information System (INIS)

    Zolotukhin, M.N.; Kveder, V.V.; Osip'yan, Yu.A.

    1981-01-01

    The annealing kinetics of the (EPR) dislocation signal (D-centers) in silicon is studied. The disappearance of the dislocation EPR signal as a result of annealing is ascribed to rearrangement of the nuclei of the partial dislocations accompanied by pairwise ''closing'' of the broken bonds in the S=0 state. The height of the energy barrier for the rearrangement process is approximately 2 eV. A residual ''nonannealing'' EPR signal is observed in strongly deformed silicon crystals. It resembles an isotropic line with a width approximately 7.5 Oe and a g-factor approximately 2.006. It is suggested that the respective EPR centers (O-centers) are similar to the EPR centers in amorphic silicon [ru

  3. Magnetic, catalytic, EPR and electrochemical studies on binuclear ...

    Indian Academy of Sciences (India)

    Magnetic, catalytic, EPR and electrochemical studies on binuclear copper(II) complexes ... to the oxidation of 3,5-di--butylcatechol to the corresponding quinone. ... EPR spectral studies in methanol solvent show welldefined four hyperfine ...

  4. EPR spectroscopy of complex biological iron-sulfur systems.

    Science.gov (United States)

    Hagen, Wilfred R

    2018-02-21

    From the very first discovery of biological iron-sulfur clusters with EPR, the spectroscopy has been used to study not only purified proteins but also complex systems such as respiratory complexes, membrane particles and, later, whole cells. In recent times, the emphasis of iron-sulfur biochemistry has moved from characterization of individual proteins to the systems biology of iron-sulfur biosynthesis, regulation, degradation, and implications for human health. Although this move would suggest a blossoming of System-EPR as a specific, non-invasive monitor of Fe/S (dys)homeostasis in whole cells, a review of the literature reveals limited success possibly due to technical difficulties in adherence to EPR spectroscopic and biochemical standards. In an attempt to boost application of System-EPR the required boundary conditions and their practical applications are explicitly and comprehensively formulated.

  5. Automated dose estimation for lost or damaged dosimeters

    International Nuclear Information System (INIS)

    Thompson, W.L.; Deininger, R.J.

    1988-01-01

    This paper reports that some dosimetry vendors will compute doses for their customers' lost/damaged dosimeters based upon an average of recent dosimeter readings. However, the vendors usually require authorization from the customer for each such occurrence. Therefore, the tedious task of keeping track of the overdue status of each missing dosimeter and constantly notifying the vendor is still present. Also, depending on the monthly variability of a given person's doses, it may be more valid to use the employee's average dose, his/her highest dose over a recent period, an average dose of other employees with similar job duties for that period, or the maximum permissible dose. Thus, the task of estimating doses for lost/damaged dosimeters cannot be delegated to dosimetry vendor. Instead, the radiation safety department must sue the data supplied by the vendor as input for performing estimates. The process is performed automatically at the Medical Center Hospital of Vermont using a personal computer and a relational database

  6. Investigating potential physicochemical errors in polymer gel dosimeters

    International Nuclear Information System (INIS)

    Sedaghat, Mahbod; Lepage, Martin; Bujold, Rachel

    2011-01-01

    Measurement errors in polymer gel dosimetry can originate either during irradiation or scanning. One concern related to the exothermic nature of polymerization reaction was that the heat released in polymer gel dosimeters during irradiation modifies their dose response. In this paper, the effect of heat released from the exothermal polymerization reaction on the dose response of a number of dosimeters was studied. In addition, we investigated whether heat-generated geometric distortion existed in newly proposed gel dosimeters that contain highly thermoresponsive polymers. Our results suggest that despite a significant internal temperature increase in some gel compositions, their dose responses are not affected when oxygen is well expelled mechanically from the gel mixture. We also report on significant pre-irradiation instability in some recently developed polymer gel dosimeters but that geometric distortions were not observed. Data obtained by a set of small calibration vials are compared to those obtained from larger phantoms, and potential physicochemical causes of deviations between them are identified.

  7. Investigating potential physicochemical errors in polymer gel dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Sedaghat, Mahbod; Lepage, Martin [Centre d' imagerie moleculaire de Sherbrooke, Departement de medecine nucleaire et radiobiologie, Universite de Sherbrooke, Sherbrooke, QC (Canada); Bujold, Rachel, E-mail: martin.lepage@usherbrooke.ca [Service de radio-oncologie, Centre hospitalier universitaire de Sherbrooke, Sherbrooke, QC (Canada)

    2011-09-21

    Measurement errors in polymer gel dosimetry can originate either during irradiation or scanning. One concern related to the exothermic nature of polymerization reaction was that the heat released in polymer gel dosimeters during irradiation modifies their dose response. In this paper, the effect of heat released from the exothermal polymerization reaction on the dose response of a number of dosimeters was studied. In addition, we investigated whether heat-generated geometric distortion existed in newly proposed gel dosimeters that contain highly thermoresponsive polymers. Our results suggest that despite a significant internal temperature increase in some gel compositions, their dose responses are not affected when oxygen is well expelled mechanically from the gel mixture. We also report on significant pre-irradiation instability in some recently developed polymer gel dosimeters but that geometric distortions were not observed. Data obtained by a set of small calibration vials are compared to those obtained from larger phantoms, and potential physicochemical causes of deviations between them are identified.

  8. Validation of an Innovative Satellite-Based UV Dosimeter

    Science.gov (United States)

    Morelli, Marco; Masini, Andrea; Simeone, Emilio; Khazova, Marina

    2016-08-01

    We present an innovative satellite-based UV (ultraviolet) radiation dosimeter with a mobile app interface that has been validated by exploiting both ground-based measurements and an in-vivo assessment of the erythemal effects on some volunteers having a controlled exposure to solar radiation.Both validations showed that the satellite-based UV dosimeter has a good accuracy and reliability needed for health-related applications.The app with this satellite-based UV dosimeter also includes other related functionalities such as the provision of safe sun exposure time updated in real-time and end exposure visual/sound alert. This app will be launched on the global market by siHealth Ltd in May 2016 under the name of "HappySun" and available both for Android and for iOS devices (more info on http://www.happysun.co.uk).Extensive R&D activities are on-going for further improvement of the satellite-based UV dosimeter's accuracy.

  9. Calibration and performance testing of electronic personal dosimeters (EPD)

    International Nuclear Information System (INIS)

    Banaga, H.A.

    2008-04-01

    In modern radiation protection practices, active personal dosimeters are becoming absolutely necessary operational tools for satisfying the ALARA principle. The aim of this work was to carry out calibration and performance testing of ten electronic personal dosimeters (EPD) used for the individual monitoring. The EPDs were calibrated in terms of operation radiation protection quantity, personal dose equivalent, Hp (10). Calibrations were carried out at three of x-ray beam qualities described in ISO 4037 namely 60, 100 and 150 kV in addition to Cs-137 gamma ray quality. The calibrations were performed using polymethylmethacrylate (PMMA) phantom with dimensions 20*20*15 cm 3 . Conversion coefficient Hp (10)/K air for the phantom was also calculated. The response and linearity of the dosimeter at the specified energies were also tested. The EPDs tested showed that the calibration coefficient ranged from 0.60 to 1.31 and an equivalent response for the specified energies that ranged from 0.76 to 1.67. The study demonstrated the possibility of using non standard phantom for calibrating dosimeters used for individual monitoring. The dosimeters under study showed a good response in all energies except the response in quality 100 kV. The linearity of the dosimeters was within ±15%, with the exception of the quality 100 kV where this limit was exceeded.(Author)

  10. Performance testing of beta dosimeters used at Department of Energy facilities

    International Nuclear Information System (INIS)

    Roberson, P.L.; Holbrook, K.L.; Pappin, J.L.

    1983-01-01

    A performance test based on the American national draft standard N13.11 was conducted for dosimeter systems in use at Department of Energy facilities. The large differences in dosimeter response found were due to use of different calibration source standards and different dosimeter designs. Differences in 90 Sr/ 90 Y calibrations were approximately 20% or less for all but one participant. The differences observed were attributed to variable thicknesses of dosimeter elements and variable source irradiation geometries. Improved beta calibration standards will result if irradiation specifications include acceptable ranges from the depth-dose characteristics. The low-energy beta responses observed were consistent with the thicknesses of dosimeter sensitive elements and overlying filtration

  11. Indoor radon level measurements in Iran using AEOI passive dosimeters

    International Nuclear Information System (INIS)

    Sohrabi, M.; Solaymanian, A.R.

    1988-01-01

    A passive radon diffusion dosimeter was developed at the RPD of AEOI for nationwide indoor radon level measurements. Several parameters of the dosimeter were studied. Radon levels were determined in about 250 houses in Ramsar (a high natural radiation area), Tehran, Babolsar and Gonabad. In this paper, the results of some dosimeter parameters as well as radon levels in indoor air are reported

  12. Limits in EPR dosimetry for irradiated dried fruits discrimination

    International Nuclear Information System (INIS)

    Brasoveanu, Mirela M. E-mirela@alpha.infim.ro; Nemtanu, R.; Minea, R.; Grecu, V.V.

    2003-01-01

    Irradiation of food induces free radical species. EPR dosimetry in irradiated goods puts in evidence if these radicals are stable in environmental condition. Irradiation of dried fruits has been carried out. Their behaviour under irradiation was investigated and correlation between EPR signal and irradiation dose was determined. Electrons of 6 MeV (mean energy) and doses up to 10 kGy were used. EPR spectra were recorded with a Jeol spectrometer, JES-ME-3X tip, with a 100 kHz modulation. The dried fruits can be separated into categories depending on the EPR signal intensity. Strong signals are observed in those fruits in which possible crystalline-like phases exist. As the amount of crystallized sugar decreases, the EPR signals become weaker. Dependencies on irradiation dose give a linear correlation below 10 kGy. The spectra are compared to irradiated sugar and differences and similarities are discussed. (authors)

  13. Approving of personal dosimeter services

    International Nuclear Information System (INIS)

    Bergman, K.; Malmqvist, L.

    2001-09-01

    The Swedish regulation SSI FS 98:5 requires that radiological workers of category A use dosemeters from an approved personal dosimetry service. The regulation also includes certain specific dosimeter requirements, which are based on those presented in the Technical Recommendations by the European Commission (Report EUR 14852 EN, 1994). All services have been tested for their ability to determine Hp(10) and some of them to determine Hp(0.07) at one radiation quality. The test was performed in the interval 0.2 mSv to 100 mSv at three different dose equivalents unknown to the system owner. The 11 services operating in Sweden at the moment use 5 different types of dosimeters. The five unique systems have been tested regarding the angular and energy dependence of the response of the dosimeters. The dosimeters were irradiated to a personal dose equivalent of about 1 mSv at three photon energies and at four angles (0, 20, 40 and 60 deg. resp. ) both vertically and horizontally rotated. Only 2 of the services determine Hp(0.07) for beta and gamma radiation and were tested for this quantity. The test results for Hp(10) are all except two within the trumpet curve. For the unique systems it is shown that the uncertainty related to angular response at a specified energy is within the required ±40 % except for the lowest X-ray quality at 40 kV. The response is more dependent on photon energy than on the direction of the photon radiation and the choice of radiation quality for the calibration is of great importance for the system performance

  14. 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.

  15. Water equivalence of polymer gel dosimeters

    International Nuclear Information System (INIS)

    Sellakumar, P.; James Jebaseelan Samuel, E.; Supe, Sanjay S.

    2007-01-01

    To evaluate the water equivalence and radiation transport properties of polymer gel dosimeters over the wide range of photon and electron energies 14 different types of polymer gels were considered. Their water equivalence was evaluated in terms of effective atomic number (Z eff ), electron density (ρ e ), photon mass attenuation coefficient (μ/ρ), photon mass energy absorption coefficient (μ en /ρ) and total stopping power (S/ρ) tot of electrons using the XCOM and the ESTAR database. The study showed that the effective atomic number of polymer gels were very close ( en /ρ for all polymer gels were in close agreement ( tot of electrons in polymer gel dosimeters were within 1% agreement with that of water. From the study we conclude that at lower energy (<80keV) the polymer gel dosimeters cannot be considered water equivalent and study has to be carried out before using the polymer gel for clinical application

  16. Comparison of Panasonic’s Dosimetric System with Gamma-31 Dosimeters

    Directory of Open Access Journals (Sweden)

    Paweł Urban

    2013-01-01

    Full Text Available Equipment being used in medical or industrial institutions is often a source of ionizing radiation with different energies and types, which complicates the detection and assessment of doses. Up until now, for dosimetric measurements of ionizing radiation, Gamma-31 dosimeters have been used in the Central Mining Institute for many years. Now, this system will be expanded by a Panasonic system, for which measurement procedures were developed and comparisons with other dosimeters were held. The method is based on a four-element dosimeters UD-802 Panasonic equipped with CaSO and LiBO detectors additionally sheltered by filters of different surface mass. The use of UD-802 dosimeters, in contrast to Gamma-31 dosimeters, permits measuring radiation doses in a different range of photon energy. Consequently, it is possible to obtain a more accurate analysis of the hazards caused by gamma radiation in underground mines. The publication includes a description of the dosimetry system and presents the results of measurements conducted by means of both types of dosimeters. In order to verify the correctness of the indications of the new dosimetry system a series of measurements were carried out, which allowed examining the behaviour of the dosimeters under different environmental conditions. As a place of exposure, the selected laboratories in the Silesian Centre for Environmental Radiometry were chosen, where the work is connected with (TENORM and equipment producing ionizing radiation or containing sources of this type of radiation. Moreover, to observe the dosimeters behaviour in difficult environmental conditions, they were exposed in water treatment plants and an underground potassium salt mine.

  17. EPR trademark project delivery. The value of experience

    International Nuclear Information System (INIS)

    Leverenz, Ruediger

    2013-01-01

    We are building the EPR trademark reactor fleet. Together. With four EPR trademark projects under construction in the world, AREVA has unrivalled experience in the delivery of large-scale nuclear projects, including more than a thousand lessons learned captured from Olkiluoto 3 and Flamanville 3 projects. This book of knowledge as well as the return of experience of AREVA's and EDF's teams are now being fully leveraged on ongoing projects, especially on Flamanville 3 and Taishan, and will be incorporated in all future EPR TM projects.

  18. Some ideas on the EPR

    International Nuclear Information System (INIS)

    2003-01-01

    Facing the debate and controversial between partisans and opponents of the European Pressurized Reactor construction, the SFP energy Group aims to offer some reflexions. In this framework the following topics are discussed: the french nuclear park and its replacement, the energy costs, the nuclear reactors profitability, the generation IV reactors. The paper examines then the EPR technology and its cost to conclude on the advantage of an EPR construction, in the case of an energy policy based on the nuclear. This last point seems to be the real challenge of the problem. (A.L.B.)

  19. Characterization of Thymol blue Radiochromic dosimeters for high dose applications

    Directory of Open Access Journals (Sweden)

    Feras M. Aldweri

    2018-03-01

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

  20. PropeR: a multi disciplinary EPR system

    NARCIS (Netherlands)

    van der Linden, Helma; Boers, Gerrit; Tange, Huibert; Talmon, Jan; Hasman, Arie

    2003-01-01

    This article describes the architecture of an EPR system developed for the PropeR project. This EPR system not only aims at supporting home care of stroke patients, but is also designed in such a way that it can be ported to other medical services without much effort. We will briefly describe the

  1. 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.)

  2. 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...

  3. Pressurized water reactors: the EPR project

    International Nuclear Information System (INIS)

    Py, J.P.; Yvon, M.

    2007-01-01

    EPR (originally 'European pressurized water reactor', and now 'evolutionary power reactor') is a model of reactor initially jointly developed by French and German engineers which fulfills the particular safety specifications of both countries but also the European utility requirements jointly elaborated by the main European power companies under the initiative of Electricite de France (EdF). Today, two EPR-based reactors are under development: one is under construction in Finland and the other, Flamanville 3 (France), received its creation permit decree on April 10, 2007. This article presents, first, the main objectives of the EPR, and then, describes the Flamanville 3 reactor: reactor type and general conditions, core and conditions of operation, primary and secondary circuits with their components, main auxiliary and recovery systems, man-machine interface and instrumentation and control system, confinement and serious accidents, arrangement of buildings. (J.S.)

  4. E-PR technologies in political party activities

    OpenAIRE

    Tereshchuk Vitaliy Ivanovych

    2016-01-01

    The article discusses the role of the Internet as an important communicative tool in the field of political PR. The article reviews the characteristics of PR-activities on the Internet and the features of e-PR in the political sphere. Particular attention is paid to the system of political party’s e-PR tools.

  5. 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.)

  6. Portable dosimeter

    International Nuclear Information System (INIS)

    Buffa, A.; Caley, R.; Pfaff, K.

    1986-01-01

    A simple but very accurate portable dosimeter is described for indicating the intensity of ionizing radiation, comprising, as a unit: (a) a radiation-detection chamber having a pair of parallel, facing, electrically-conducting, radiation-permeable electrodes spaced from each other to define a volume for a gas which is ionized by the radiation when exposed thereto; (b) electric potential supply means connected across the electrodes for attracting the gas ions to the electrodes and transferring their charge to the electrodes; (c) detection circuit means connected across the electrodes and having at least one of high-frequency electromagnetic- and radiation-sensitive components for detecting the charge on the electrodes and indicating therefrom a representation of the intensity of the radiation; (d) radiation shield means surrounding the radiation-sensitive components of the detection circuit means for shielding the latter from the ionizing radiation; (e) electric shield means surrounding the sensitive components of the detection circuit means for shielding the latter from electromagnetic interference including any caused by the ionizing radiation; and (f) ion shield means potting the ion-sensitive components for shielding them from radiation-caused ambient ionization; whereby the entire dosimeter may be assembled as the unit and portably transported into various radiation sources

  7. 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. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Advances in the development of Cr-39 based neutron dosimeters

    International Nuclear Information System (INIS)

    Hadlock, D.E.; Parkhurst, M.A.

    1987-12-01

    A combination thermoluminescent dosimeter (TLD) and track etch dosimeter (TED), which can be used for detecting neutrons over a wide energy range, has been developed through recent research in passive neutron dosimetery. This dosimeter uses Li-600 TLDs to detect thermal and low energy neutrons reflected from the body, and the TED polymer of CR-39, to detect fast neutrons from proton recoil interactions with the polyethylene radiator or with CR-39 itself. Some form of the combination dosimeter is currently in use at several US Department of Energy (DOE) facilities, and its use is expected to expand over the next year to include all DOE facilities where significant neutron exposures may occur. The extensive research conducted on the TED component over the past six years has continually focused on material improvements, reduction in processing time and dosimeter handling, and ease of sample readout with the goal of automating the process as much as possible. 1 fig

  9. Increase of weakly acidic gas esophagopharyngeal reflux (EPR) and swallowing-induced acidic/weakly acidic EPR in patients with chronic cough responding to proton pump inhibitors.

    Science.gov (United States)

    Kawamura, O; Shimoyama, Y; Hosaka, H; Kuribayashi, S; Maeda, M; Nagoshi, A; Zai, H; Kusano, M

    2011-05-01

    Gastro-esophageal reflux disease (GERD)-related chronic cough (CC) may have multifactorial causes. To clarify the characteristics of esophagopharyngeal reflux (EPR) events in CC patients whose cough was apparently influenced by gastro-esophageal reflux (GER), we studied patients with CC clearly responding to full-dose proton pump inhibitor (PPI) therapy (CC patients). Ten CC patients, 10 GERD patients, and 10 healthy controls underwent 24-h ambulatory pharyngo-esophageal impedance and pH monitoring. Weakly acidic reflux was defined as a decrease of pH by >1 unit with a nadir pH >4. In six CC patients, monitoring was repeated after 8 weeks of PPI therapy. The number of each EPR event and the symptom association probability (SAP) were calculated. Symptoms were evaluated by a validated GERD symptom questionnaire. Weakly acidic gas EPR and swallowing-induced acidic/weakly acidic EPR only occurred in CC patients, and the numbers of such events was significantly higher in the CC group than in the other two groups (P pump inhibitor therapy abolished swallowing-induced acidic/weakly acidic EPR, reduced weakly acidic gas EPR, and improved symptoms (all P gas EPR and swallowing-induced acidic/weakly acidic EPR. A direct effect of acidic mist or liquid refluxing into the pharynx may contribute to chronic cough, while cough may also arise indirectly from reflux via a vago-vagal reflex in some patients. © 2011 Blackwell Publishing Ltd.

  10. Three-dimensional high dose rate dosimetry of electron beams. A combined radiochromic film, EPR and calorimetric dosimetry

    International Nuclear Information System (INIS)

    Secerov, B.; Milosavljevic, B.H.; Bacic, G.; Belgrade Univ.

    2002-01-01

    Complete text of publication follows. Aim. To examine the suitability of radiochromic film (RCF) dosimeters in determining 3D dose distribution from a pulsed electron beam source by comparing their response with alanine EPR dosimetry and calorimetry. Experimental. A FWT-60 radiochromic films (Far West Technology Inc) were used while alanine films were home made. To obtain the dose vs. penetration depth relationship, a stack of 13 films separated by aluminium plates and/or alanine films was placed perpendicular to the electron beam (Febetron, 20 ns, 1.8 MeV, 10 12 Gy/s, dose range up to 100 kGy). RC films were calibrated using 60-Co source and Fricke dosimetry. The absorbance of irradiated films was measured using 2D microdensitometry. Calorimetry was performed with a homemade quasy-adiabatic aluminum calorimeter. Results and Discussion. Microdensitometry of films (5 x 5 cm) enabled the 3D mapping of the entire radiation field with in plane resolution of 0.12 mm. The total dose for each film was obtained by image segmentation to correct for the non-linear response of films. Integrated dose for the entire stack was in good agreement (within 5%) with total absorbed energy as determined with calorimetry. The dose distribution along the beam center was determined using alanine films (1 x 1 cm) and EPR spectroscopy, and again a good agreement with the dose determined by microdensitometry of the central portion of RC films. In conclusion, the results indicate that RC films can be used for determination of 3D dose distribution even at very high dose rates

  11. Stable Chemical Dosimeters for Partial Reconstruction of Nuclear Accident Conditions

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-10-15

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

  12. Advancements in accuracy of the alanine dosimetry system. Part 1. The effects of environmental humidity

    International Nuclear Information System (INIS)

    Sleptchonok, Olga F.; Nagy, Vitaly; Desrosiers, Marc F.

    2000-01-01

    A one-year study of the EPR signal of γ-irradiated ( 60 Co) L-α-alanine with simultaneous monitoring of the cavity Q-factor was undertaken. The widespread opinion that the EPR signal remains absolutely stable under normal laboratory storage conditions is inaccurate. At 0% humidity, the signal can be regarded as stable within ±1% of its initial value for 6 months for 1 and 10 kGy doses, but for only 3 months for 100 kGy. When stored at the same relative humidity values up to 60%, the fading rates for dosimeters irradiated to 1 and 10 kGy are similar, whereas signals of dosimeters irradiated to 100 kGy fade considerably faster for all humidities. The rates of fading increase with the relative humidity, especially above 60% R. H. Environmental humidity also deteriorates the accuracy of alanine dosimetry by changing the resonant cavity Q-factor. This is particularly important when irradiated alanine dosimeters are used as instrument calibration standards. Short-term changes in alanine EPR signal amplitudes were recorded upon removal of the irradiated dosimeters from their storage environments. The importance of an in situ standard to correct for measurement errors due to environmental effects is demonstrated. (author)

  13. Automating the personnel dosimeter monitoring program

    International Nuclear Information System (INIS)

    Compston, M.W.

    1982-12-01

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

  14. Design of calibration method in neutron and individual dosimeter

    International Nuclear Information System (INIS)

    Belkhodia, M.

    1984-12-01

    Usually albedo dosemeters are calibrated with beam of monoenergetic neutrons. Since neutron energy around neutron sources varies greatly, we applied the calibration method to a mixed field whose energy spectrum lies between 0.025 ev and 10 Mev. The method is based on a mathematical model that deals with the dosimeter response as a function at the neutron energy. The measurements carried out with solid state nuclear track detectors show the dosimeter practical aspect. The albedo dosimeter calibration gave results on good agreement with the international institution recommendations

  15. Chemical dosimeter

    International Nuclear Information System (INIS)

    Baker, W.B.; Clark, D.G.

    1979-01-01

    The dosimeter may be carried by individuals e.g. at the belt and serves to monitor for vinyl-chloride vapors in industrial plants and for toxic radon gas and toxic radon gas products in mines. It contains a pump, sucking an air flow through an orifice and a filter, as well as a sensor circuit for detecting low air flow rates and a battery testing circuit. (DG) 891 HP/DG 892 MKO [de

  16. Radiation sensitive polymer gel dosimeters

    International Nuclear Information System (INIS)

    Lepage, M.; Back, S.A.J.; Baldock, C.; Whittaker, A.K.; Rintoul, L.

    2000-01-01

    Full text: Radiation sensitive gels are studied for their potential to retain a permanent 3D dose distribution for applications in radiotherapy. Co-monomers dissolved in a tissue-equivalent hydrogel undergo a polymerization reaction upon absorption of ionizing radiation. The polymer formed influences the local spin-spin relaxation time (T 2 ) of the dosimeter that can be determined using magnetic resonance imaging (MRI). The relationship between T2 and the absorbed dose was studied for different initial chemical compositions. The aim was to find a model linking the changes in T 2 with absorbed dose to the initial composition of the dosimeter. It is believed this will help designing new gel dosimeters having desired properties to minimize the uncertainty in the determination of the dose distribution. 1 H, 13 C nuclear magnetic resonance spectroscopy and FT-Raman spectroscopy were used to quantify the amount of monomers still remaining after the absorption of a given dose of radiation. This data is used to model the changes of T2 as a function of the absorbed dose. A model of fast exchange of magnetization between three proton pools was used, where the fraction of protons (f x H ) in the x th pool is obtained from the chemical composition of the dosimeter and the apparent T2 of each pool is determined for a given composition. Initially, the protons are contained in two pools; a mobile (mob), which contains the water protons and the monomers protons, and a gelatin (gela) proton pool. The mobile pool is partially depleted as polymer is formed, the protons are transferred into the polymer (pol) pool. In the figure, the experimental data along with the calculated values are plotted for three different monomer concentrations, with the gelatin concentration fixed. The model is seen to provide a good fit to the experimental data

  17. On the correlations between the particles in the EPR-paradoxon

    International Nuclear Information System (INIS)

    Treder, H.J.

    1984-01-01

    The Einstein-Podolsky-Rosen 'gedanken-experiment' does not imply non-local interactions or an 'action-at-a-distance'. Contrary, the EPR proves the measurements at one particle does not have influences at canonical variables of the other particles if the quantum-mechanical commutation relations are true. But, the EPR implices correlations between the particles which come in by 'subjective knowledge'. These correlations are a priori informations about the relative motion or, complementarily, about the motion of the center of mass. The impression of an action-at-a-distance is produced by the use of usual particle coordinates in the EPR-arrangements. The discussion of the Einstein-Podolsky-Rosen 'gedanken-experiment' (EPR) has been going on over fifty years. Einstein, Podolsky, and Rosen formulated their famous paradox in 1935, and in the discussion between N. Bohr (1935, 1949) and Einstein (1936, 1948); A. Einstein (1948) made his point that the EPR implied an 'action-at-a-distance' for quantum-mechanical particles (without obvious classical interactions). His argument is the starting point for the recent discussion about EPR and causality (see A. Aspect 1981). (author)

  18. 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

  19. EPR and X-ray diffraction investigation of some Greek marbles and limestones

    International Nuclear Information System (INIS)

    Duliu, Octavian; Grecu, Maria Nicoleta; Cristea, Corina

    2009-01-01

    Twelve different marble and limestone samples collected from well-known Greek quarries have been investigated by X-ray diffraction and electron paramagnetic resonance (EPR). X-ray diffraction spectra permitted to determine both major (calcite and dolomite) and minor (quartz or magnesite) mineralogical components. EPR has been used to investigate the same samples unirradiated and after 10 kGy gamma-ray irradiation. The unirradiated samples display typical EPR spectra of Mn 2+ in calcite and dolomite as well as a superposition of these while some samples displayed EPR free radicals signals of centers (low field signal) and centers (high field signal). From X-ray diffraction and EPR spectra it was possible to extract numerical values of several numerical parameters such as dolomite to calcite ratio, EPR intensity parameter, and low field to high field EPR signals intensity ratio. These values as well as the correlation coefficients between the digital functions that described the low field Mn 2+ ions EPR line have been used as entry data for cluster analysis to quantify the resemblance and differences between analyzed samples. (authors)

  20. The LLNL CR-39 personnel neutron dosimeter

    International Nuclear Information System (INIS)

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

    1987-01-01

    We developed a personnel neutron dosimetry system based on the electrochemical etching of CR-39 plastic at elevated temperatures. The doses obtained using this dosimeter system are more accurate than those obtained using other dosimetry systems, especially when varied neutron spectra are encountered. This CR-39 dosimetry system does not have the severe energy dependence that exists with albedo neutron dosimeters or the fading and reading problems encountered with NTA film. 3 refs., 4 figs

  1. Perfection of the individual photographic emulsion dosimeter

    International Nuclear Information System (INIS)

    Soudain, G.

    1960-01-01

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

  2. Dosimetric characteristics of PASSAG as a new polymer gel dosimeter with negligible toxicity

    Science.gov (United States)

    Farhood, Bagher; Abtahi, Seyed Mohammad Mahdi; Geraily, Ghazale; Ghorbani, Mehdi; Mahdavi, Seied Rabi; Zahmatkesh, Mohammad Hasan

    2018-06-01

    Despite many advantages of polymer gel dosimeters, their clinical use is only not realized now. Toxicity of polymer gel dosimeters can be considered as one of their main limitations for use in routine clinical applications. In the current study, a new polymer gel dosimeter is introduced with negligible toxicity. For this purpose, 2-Acrylamido-2-Methy-1-PropaneSulfonic acid (AMPS) sodium salt monomer was replaced instead of acrylamide monomer used in PAGAT gel dosimeter by using %6 T and %50 C to the gel formula and the new formulation is called PASSAG (Poly AMPS Sodium Salt and Gelatin) polymer gel dosimeter. The irradiation of gel dosimeters was carried out using a Co-60 therapy machine. MRI technique was used to quantify the dose responses of the PASSAG gel dosimeter. Then, the MRI responses (R2) of the gel dosimeter was analyzed at different dose values, post-irradiation times, and scanning temperatures. The results showed that the new gel formulation has a negligible toxicity and it is also eco-friendly. In addition, carcinogenicity and genetic toxicity tests are negative for the monomer used in PASSAG. The radiological properties of PASSAG gel dosimeter showed that this substance can be considered as a soft tissue/water equivalent material. Furthermore, dosimetric evaluation of the new polymer gel dosimeter revealed an excellent linear R2-dose response in the evaluated dose range (0-15 Gy). The R2-dose sensitivity and dose resolution of PASSAG gel dosimeter were 0.081 s-1Gy-1 (in 0-15 Gy dose range) and 1 Gy (in 0-10 Gy dose range), respectively. Moreover, it was shown that the R2-dose sensitivity and dose resolution of the new gel dosimeter improves over time after irradiation. It was also found that the R2 response of the PASSAG gel dosimeter has less dependency to the 18, 20, and 24 °C scanning temperature in comparison to that of room temperature (22 °C).

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

    Science.gov (United States)

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

    2013-07-17

    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. In this paper, we give the definition and practical implementation of a new EPR parameter based on the signal shape that we call the R10 factor. This parameter was originally defined in the case of a single symmetric EPR line and used as a new datation method for organic matter in the field of exobiology. Combined to classical EPR parameters, the proposed shape parameter provides a full description of an EPR spectrum and opens the way to novel applications like datation. Such a parameter is a powerful tool for future EPR studies, not only of carbonaceous matter, but also of any substance which spectrum exhibits a single symmetric line. The paper is a literate program-written using Noweb within the Org-mode as provided by the Emacs editor- and it also describes the full data analysis pipeline that computes the R10 on a real EPR spectrum.

  4. Overview of LBB implementation for the EPR

    International Nuclear Information System (INIS)

    Cauquelin, C.

    1997-01-01

    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

  5. 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.

  6. Antioxidant effect of green tea on polymer gel dosimeter

    International Nuclear Information System (INIS)

    Samuel, E J J; Sathiyaraj, P; Deena, T; Kumar, D S

    2015-01-01

    Extract from Green Tea (GTE) acts as an antioxidant in acrylamide based polymer gel dosimeter. In this work, PAGAT gel was used for investigation of antioxidant effect of GTE.PAGAT was called PAGTEG (Polyacrylamide green tea extract gel dosimeter) after adding GTE. Free radicals in water cause pre polymerization of polymer gel before irradiation. Polyphenols from GTE are highly effective to absorb the free radicals in water. THPC is used as an antioxidant in polymer gel dosimeter but here we were replaced it by GTE and investigated its effect by spectrophotometer. GTE added PAGAT samples response was lower compared to THPC added sample. To increase the sensitivity of the PAGTEG, sugar was added. This study confirmed that THPC was a good antioxidant for polymer gel dosimeter. However, GTE also can be used as an antioxidant in polymer gel if use less quantity (GTE) and add sugar as sensitivity enhancer

  7. Optimizing the sensitivity and radiological properties of the PRESAGE® dosimeter using metal compounds

    International Nuclear Information System (INIS)

    Alqathami, Mamdooh; Blencowe, Anton; Qiao, Greg; Adamovics, John; Geso, Moshi

    2012-01-01

    The aim of this study is to investigate the radiation-modifying effects of incorporating commercially available bismuth-, tin- and zinc-based compounds in the composition of the PRESAGE ® dosimeter, and the feasibility of employing such compounds for radiation dose enhancement. Furthermore, we demonstrate that metal compounds can be included in the formulation to yield water-equivalent PRESAGE ® dosimeters with enhanced dose response. Various concentrations of the metal compounds were added to a newly developed PRESAGE ® formulation and the resulting dosimeters were irradiated with 100 kV and 6 MV photon beams. A comparison between sensitivity and radiological properties of the PRESAGE ® dosimeters with and without the addition of metal compounds was carried out. Optical density changes of the dosimeters before and after irradiation were measured using a spectrophotometer. In general, when metal compounds were incorporated in the composition of the PRESAGE ® dosimeter, the sensitivity of the dosimeters to radiation dose increased depending on the type and concentration of the metal compound, with the bismuth compound showing the highest dose enhancement factor. In addition, these metal compounds were also shown to improve the retention of the post-response absorption value of the PRESAGE ® dosimeter over a period of 2 weeks. Thus, incorporating 1–3 mM (ca. 0.2 wt%) of any of the three investigated metal compounds in the composition of the PRESAGE ® dosimeter is found to be an efficient way to enhance the sensitivity of the dosimeter to radiation dose and stabilize its post-response for longer times. Furthermore, the addition of small amounts of the metal compounds also accelerates the polymerization of the PRESAGE ® dosimeter precursors, significantly reducing the fabrication time. Finally, a novel water-equivalent PRESAGE ® dosimeter formula optimized with metal compounds is proposed for clinical use in both kilovoltage and megavoltage radiotherapy

  8. EPR study of free radicals in bread

    Science.gov (United States)

    Yordanov, Nicola D.; Mladenova, Ralitsa

    2004-05-01

    The features of the recorded EPR spectra of paramagnetic species formed in bread and rusk are reported. The appearance of free radicals in them is only connected with their thermal treatment since the starting materials (flour and grains) exhibit very weak EPR signal. The obtained EPR spectra are complex and indicate that: (i) the relative number of paramagnetic species depends on the temperature and treating time of the raw product; (ii) the g-values are strongly temperature dependent with a tendency to coincide at t≥220 °C. Because of the relatively low (150-220 °C) temperature of thermal treatment, the studied free radicals can be assumed to appear in the course of the browning (Maillard) reaction and not to the carbonization of the material.

  9. EPR of impurity ions in disordered solids

    International Nuclear Information System (INIS)

    Kliava, J.

    1986-01-01

    The state of the art in the EPR spectroscopy of disordered solids is reviewed and theoretical aspects of the EPR shape in disordered systems are discussed. Emphasis is placed on the concept of the joint probability density of the spin Hamiltonian parameters. A survey of experimental data is provided on distributions of spin Hamiltonian parametes obtained using computer simulation techniques. A quantitative information is given on the short-range ordering in disordered materials available from EPR studies. A procedure of extracting such type of data which consists in a transformation from the distribution of the spin Hamiltonian parameters to that of atomic coordinates in the surrounding of a paramagnetic center is outlined. Numerical estimates of the degree of continuous disorder are reviewed

  10. X- and Q-band EPR studies on fine powders of irradiated plants. New approach for detection of their radiation history by using Q-band EPR spectrometry

    International Nuclear Information System (INIS)

    Yordanov, Nicola D.; Aleksieva, Katerina

    2004-01-01

    X- and Q-band EPR studies after γ-irradiation of some dry spices and aromatic herbs are reported. Before irradiation all samples show only one singlet line in X-band EPR, whereas the Q-band EPR spectrum of the same samples is a superposition of two individual spectra--one corresponding to the above EPR signal, with an anisotropic spectrum, and a second one consisting of six lines due to the Mn 2+ naturally present in plants. The radiation induced EPR signal due to cellulose free radicals was not detected after γ-irradiation, but only the increase of the natural signal present before the irradiation. The fading kinetic of this EPR signal was monitored in three cases--when samples were kept in plastic bags without any special conditioning after irradiation, when samples were covered with paraffin before irradiation and when samples were dried at 60 deg. C for 1 h before irradiation. The studies show that stability of radiation induced EPR signals decreases in the order of: paraffin covered > heated before irradiation > kept at room conditions. The two EPR spectra in the Q-band--one with radiation dependent intensity and a second due to Mn 2+ , which is radiation independent allow identification of previous radiation treatment based on the fact that Mn 2+ quantity in the sample is constant whereas the quantity of radiation-induced free radicals is temperature dependent. It was found that for irradiated samples the ratio between EPR intensity of the free radicals and that of Mn 2+ before and after heating decreases with 50-60% whereas for non-irradiated samples it is ca. 10-15%

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

    Science.gov (United States)

    Yordanov, N. D.; Aleksieva, K.; Dimitrova, A.; Georgieva, L.; Tzvetkova, E.

    2006-09-01

    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. 50 days, 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=2.0023±0.0003 and g⊥=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 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.

  12. An NMR relaxometry and gravimetric study of gelatin-free aqueous polyacrylamide dosimeters

    International Nuclear Information System (INIS)

    Babic, Steven; Schreiner, L John

    2006-01-01

    In conformal radiation therapy, a high dose of radiation is given to a target volume to increase the probability of cure, and care is taken to minimize the dose to surrounding healthy tissue. The techniques used to achieve this are very complicated and the precise verification of the resulting three-dimensional (3D) dose distribution is required. Polyacrylamide gelatin (PAG) dosimeters with magnetic resonance imaging and optical computed tomography scanning provide the required 3D dosimetry with high spatial resolution. Many basic studies have characterized these chemical dosimeters that polymerize under irradiation. However, the investigation of the fundamental properties of the radiation-induced polymerization in PAG dosimeters is complicated by the presence of the background gelatin matrix. In this work, a gelatin-free model system for the study of the basic radiation-induced polymerization in PAG dosimeters has been developed. Experiments were performed on gelatin-free dosimeters, named aqueous polyacrylamide (APA) dosimeters, containing equal amounts of acrylamide and N,N'-methylene-bisacrylamide. The APA dosimeters were prepared with four different total monomer concentrations (2, 4, 6 and 8% by weight). Nuclear magnetic resonance (NMR) spin-spin and spin-lattice proton relaxation measurements at 20 MHz, and gravimetric analyses performed on all four dosimeters, show a continuous degree of polymerization over the dose range of 0-25 Gy. The developed NMR model explains the relationship observed between the relaxation data and the amount of crosslinked polymer formed at each dose. This model can be extended with gelatin relaxation data to provide a fundamental understanding of radiation-induced polymerization in the conventional PAG dosimeters

  13. Holographic EPR Pairs, Wormholes and Radiation

    OpenAIRE

    Chernicoff, Mariano; Güijosa, Alberto; 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 determi...

  14. EPR of alanine irradiated by neutrons

    International Nuclear Information System (INIS)

    Pivovarov, S.P.; Seredavina, T.A.; Zhdanov, S.V.; Mul'gin, S.I.; Zhakparov, R.K.

    2001-01-01

    In the work the first results of EPR studies of alanine, irradiated with diverse doses at neutron cyclotron generator different conditions and on the critical reactor stand are presented. A dose linearity dependence of EPR signal is observing, the methods of γ-background contribution separation are discussed. Obtain results is giving the basis to recommendation of alanine as an effective detector irradiation. However it is demanded the farther study on clarification of radiation sensitivity value dependence on the neutron energy spectrum form

  15. Design, construction and characterization of a dosimeter for neutron radiation

    International Nuclear Information System (INIS)

    Souto, Eduardo de Brito

    2007-01-01

    An individual dosimeter for neutron-gamma mixed field dosimetry was design and developed aiming monitoring the increasing number of workers potentially exposed to neutrons. The proposed dosimeter was characterized to an Americium-Beryllium source spectrum and dose range of radiation protection interest (up to 20 mSv). Thermoluminescent albedo dosimetry and nuclear tracks dosimetry, traditional techniques found in the international literature, with materials of low cost and national production, were used. A commercial polycarbonate, named SS-1, was characterized for solid state tack detector application. The chemical etching parameters and the methodology of detectors evaluation were determined. The response of TLD-600, TLD-700 and SS-1 were studied and algorithms for dose calculation of neutron and gamma radiation of Americium- Beryllium sources were proposed. The ratio between thermal, albedo and fast neutrons responses, allows analyzing the spectrum to which the dosimeter was submitted and correcting the track detector response to variations in the radiation incidence angle. The new dosimeter is fully characterized, having sufficient performance to be applied as neutron dosimeter in Brazil. (author)

  16. A personal radio-frequency dosimeter with cumulative-dose recording capabilities

    International Nuclear Information System (INIS)

    Rochelle, R.W.; Moore, M.R.; Thomas, R.S.; Ewing, P.D.; Hess, R.A.; Hoffheins, B.S.

    1990-01-01

    The radio-frequency (rf) dosimeter developed by the Oak Ridge National Laboratory is a portable, pocket-sized cumulative-dose recording device designed to detect and record the strengths and durations of electric fields present in the work areas of naval vessels. The device measures an integrated dose and records the electric fields that exceed the permissible levels set by the American National Standards Institute. Features of the rf dosimeter include a frequency range of 30 MHz to 10 GHz and a three-dimensional sensor. Data obtained with the rf dosimeter will be used to determine the ambient field-strength profile for shipboard personnel over an extended time. Readings are acquired and averaged over a 6-min period corresponding to the rise time of the core body temperature. These values are stored for up to 6 months, after which the data are transferred to a computer via the dosimeter's serial port. The rf dosimeter should increase knowledge of the levels of electric fields to which individuals are exposed. 13 refs., 16 figs., 2 tabs

  17. Development and characterization of real-time wide-energy range personal neutron dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Takashi; Tsujimura, Norio (Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center); Yamano, Toshiya; Suzuki, Toshikazu; Okamoto, Eisuke

    1994-04-01

    The authors developed a real-time personal neutron dosimeter which could give neutron dose equivalent over wide energy region from thermal to 10 odd MeV by using 2 silicon detectors, fast neutron sensor and slow neutron sensor. The energy response of this dosimeter was evaluated under thermal neutron field, monoenergetic neutron field between 200 keV and 15 MeV, and moderated [sup 252]Cf neutron field. The neutron dose equivalent was estimated by adding neutron dose equivalent below 1 MeV given by slow neutron sensor and that above 1 MeV by fast neutron sensor. It was verified from various field tests that this dosimeter is able to give neutron dose equivalent within a factor of 2 margin of accuracy in reactor, accelerator, fusion research and nuclear fuel handling facilities. This dosimeter has more than one order higher sensitivity than conventional personal neutron dosimeters and is insensitive to [gamma]-rays up to about 500 mSv/h. This dosimeter will soon be commercially available as a personal dosimeter which gives neutron and [gamma]-ray dose equivalents simultaneously by installing [gamma]-ray silicon sensor. (author).

  18. Dental tissue as a thermoluminescence dosimetry dosimeter

    International Nuclear Information System (INIS)

    Solaimani, F.; Zahmatkesh, M.H.; Akhlaghpoor, Sh.

    2003-01-01

    Background: Thermoluminescence dosimetry is one of the dosimetry procedures used widely as routine and personal dosimeters. In order to extend this kind of dosimeters, dental tissue has been examined and was found promising as a Thermoluminescence Dosimetry dosimeter. Materials and Methods: In this study, 70 health teeth were collected. The only criterion, wich was considered for selection of the teeth, was the healthiness of them regardless of age and gender of the donors. All collected samples were washed and cleaned and milled uniformly. The final powder had a uniform grain size between 100-300 micrometer. The sample was divided into four groups. Group A and B were used for measurement of density and investigation of variation of thermoluminescent characteristics with temperature respectively. Groups C and D were used for investigation of variation of thermoluminescent intensity with dose and fading of this intensity with time. In all cases the results obtained with dental tissue were compared to a standard LiF, thermoluminescence dosimetry dosimeter. Results: It was found that, average density of the dental tissue was 1.570 g/cm 3 , which is comparable to density of LiF, which is 1.612g/cm 3 . It was also concluded that the range of 0-300 d ig C , dental tissue has a simple curve with two specific peaks at 140 and 25 d ig C respectively. The experiment also showed that, the variation of relative intensity versus dose is linear in the range of 0.04-0.1 Gy. The fading rate of dental tissue is higher than LiF but still in the acceptable range (14% per month in compare to 5.2% per month). Conclusion: Dental tissue as a natural dosimeter is comparable with Thermoluminescence Dosimetry and can be used in accidental events with a good approximation

  19. Experimental evaluation of a MOSFET dosimeter for proton dose measurements

    International Nuclear Information System (INIS)

    Kohno, Ryosuke; Nishio, Teiji; Miyagishi, Tomoko; Hirano, Eriko; Hotta, Kenji; Kawashima, Mitsuhiko; Ogino, Takashi

    2006-01-01

    The metal oxide semiconductor field-effect transistor (MOSFET) dosimeter has been widely studied for use as a dosimeter for patient dose verification. The major advantage of this detector is its size, which acts as a point dosimeter, and also its ease of use. The commercially available TN502RD MOSFET dosimeter manufactured by Thomson and Nielsen has never been used for proton dosimetry. Therefore we used the MOSFET dosimeter for the first time in proton dose measurements. In this study, the MOSFET dosimeter was irradiated with 190 MeV therapeutic proton beams. We experimentally evaluated dose reproducibility, linearity, fading effect, beam intensity dependence and angular dependence for the proton beam. Furthermore, the Bragg curve and spread-out Bragg peak were also measured and the linear-energy transfer (LET) dependence of the MOSFET response was investigated. Many characteristics of the MOSFET response for proton beams were the same as those for photon beams reported in previous papers. However, the angular MOSFET responses at 45, 90, 135, 225, 270 and 315 degrees for proton beams were over-responses of about 15%, and moreover the MOSFET response depended strongly on the LET of the proton beam. This study showed that the angular dependence and LET dependence of the MOSFET response must be considered very carefully for quantitative proton dose evaluations

  20. The effect of thermal treatment on radiation-induced EPR signals in tooth enamel

    International Nuclear Information System (INIS)

    Vorona, I.P.; Ishchenko, S.S.; Baran, N.P.

    2005-01-01

    The effect of thermal treatment on the radiation-induced EPR spectrum of tooth enamel was studied. Annealing before sample irradiation was found to increase enamel radiation sensitivity by more than 40%. Depending on the annealing conditions the EPR signals of three supplementary radiation radicals were observed in addition to the main signal caused by CO 2 - radicals. It was found that the presence of these signals in the enamel EPR spectra provides evidence of sample annealing. The possibility of obtaining information about sample history by studying the additional EPR signals is discussed. It can be important to EPR dating and EPR dosimetry

  1. ISS protocol for EPR tooth dosimetry

    International Nuclear Information System (INIS)

    Onori, S.; Aragno, D.; Fattibene, P.; Petetti, E.; Pressello, M.C.

    2000-01-01

    The accuracy in Electron Paramagnetic Resonance (EPR) dose reconstruction with tooth enamel is affected by sample preparation, dosimetric signal amplitude evaluation and unknown dose estimate. Worldwide efforts in the field of EPR dose reconstruction with tooth enamel are focused on the optimization of the three mentioned steps in dose assessment. In the present work, the protocol implemented at ISS in the framework of the European Community Nuclear Fission Safety project 'Dose Reconstruction' is presented. A combined mechanical-chemical procedure for ground enamel sample preparation is used. The signal intensity evaluation is carried out with powder spectra simulation program. Finally, the unknown dose is evaluated individually for each sample with the additive dose method. The unknown dose is obtained by subtracting a mean native dose from the back-extrapolated dose. As an example of the capability of the ISS protocol in unknown dose evaluation, the results obtained in the framework of the 2nd International Intercomparison on EPR tooth enamel dosimetry are reported

  2. EPR of radiation defects in lithium-oxyfluoride glass ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Fedotovs, A; Rogulis, U; Sarakovskis, A; Dimitrocenko, L, E-mail: andris-f@navigator.l [Institute of Solid State Physics, University of Latvia, Kengaraga st. 8, LV-1063, Riga (Latvia)

    2010-11-01

    We studied oxyfluoride composites based on lithium silicate glasses with yttrium fluorides and rare-earth dopants. The electron paramagnetic resonance (EPR) has been used to obtain information about radiation induced defects in these materials. Spectra have been measured before and after X-ray irradiation at room temperature and at liquid nitrogen temperature. Fluoride crystallites within samples were created by means of thermal treatment at specific temperatures. EPR spectra of radiation induced defects in oxyfluoride glass ceramics, in which crystallites have not been yet created, show no explicit hfs interaction of fluorine nuclei. However, in glass ceramics, which already contains fluoride crystallites, the hfs characteristic to fluorine nuclei appears in the EPR spectra. EPR hyperfine structure could be explained within a model of an F-type centre in YF{sub 3} crystalline phase.

  3. EPR of radiation defects in lithium-oxyfluoride glass ceramics

    Science.gov (United States)

    Fedotovs, A.; Rogulis, U.; Sarakovskis, A.; Dimitrocenko, L.

    2010-11-01

    We studied oxyfluoride composites based on lithium silicate glasses with yttrium fluorides and rare-earth dopants. The electron paramagnetic resonance (EPR) has been used to obtain information about radiation induced defects in these materials. Spectra have been measured before and after X-ray irradiation at room temperature and at liquid nitrogen temperature. Fluoride crystallites within samples were created by means of thermal treatment at specific temperatures. EPR spectra of radiation induced defects in oxyfluoride glass ceramics, in which crystallites have not been yet created, show no explicit hfs interaction of fluorine nuclei. However, in glass ceramics, which already contains fluoride crystallites, the hfs characteristic to fluorine nuclei appears in the EPR spectra. EPR hyperfine structure could be explained within a model of an F-type centre in YF3 crystalline phase.

  4. Reconstructing Bohr's Reply to EPR in Algebraic Quantum Theory

    Science.gov (United States)

    Ozawa, Masanao; Kitajima, Yuichiro

    2012-04-01

    Halvorson and Clifton have given a mathematical reconstruction of Bohr's reply to Einstein, Podolsky and Rosen (EPR), and argued that this reply is dictated by the two requirements of classicality and objectivity for the description of experimental data, by proving consistency between their objectivity requirement and a contextualized version of the EPR reality criterion which had been introduced by Howard in his earlier analysis of Bohr's reply. In the present paper, we generalize the above consistency theorem, with a rather elementary proof, to a general formulation of EPR states applicable to both non-relativistic quantum mechanics and algebraic quantum field theory; and we clarify the elements of reality in EPR states in terms of Bohr's requirements of classicality and objectivity, in a general formulation of algebraic quantum theory.

  5. Early development and characterization of a DNA-based radiation dosimeter

    Science.gov (United States)

    Avarmaa, Kirsten A.

    It is the priority of first responders to minimize damage to persons and infrastructure in the case of a nuclear emergency due to an accident or deliberate terrorist attack -- if this emergency includes a radioactive hazard, first responders require a simple-to-use, accurate and complete dosimeter for radiation protection purposes in order to minimize the health risk to these individuals and the general population at large. This work consists of the early evaluation of the design and performance of a biologically relevant dosimeter which uses DNA material that can respond to the radiation of any particle type. The construct consists of fluorescently tagged strands of DNA. The signalling components of this dosimeter are also investigated for their sensitivity to radiation damage and light exposure. The dual-labelled dosimeter that is evaluated in this work gave a measurable response to gamma radiation at dose levels of 10 Gy for the given detector design and experimental setup. Further testing outside of this work confirmed this finding and indicated a working range of 100 mGy to 10 Gy using a custom-built fluorimeter as part of a larger CRTI initiative. Characterization of the chromatic components of the dosimeter showed that photobleaching is not expected to have an effect on dosimeter performance, but that radiation can damage the non-DNA signalling components at higher dose levels, although this damage is minimal at lower doses over the expected operating ranges. This work therefore describes the early steps in the quantification of the behaviour of the DNA dosimeter as a potential biologically-based device to measure radiation dose.

  6. Dosimetry of blood irradiation using an alanine/ESR dosimeter

    International Nuclear Information System (INIS)

    Chen, F.; Covas, D.T.; Baffa, O.

    2001-01-01

    A batch of 80 DL-alanine dosimeters was supplied to Hemocentro of the Hospital and Clinics of Faculdade de Medicina de Ribeirao Preto (HC-FMRP) SP, Brazil for the purpose of quality control of the radiation dose delivered to blood bags. The irradiation was made using two (40x40) cm 2 parallel opposed radiation fields each with 80 cm of source to surface distance in the Radiotherapy Section of HC-FMRP with the 60 Co teletherapy unit. The calculated radiation absorbed dose at the center of the box was 20 Gy. The dosimeter readings were performed using a Varian E-4 ESR Spectrometer operating in X-band. For the 80 dosimeters and over the irradiation volume throughout a blood bag, the minimum and maximum doses were 14 and 23 Gy, respectively. The mean dose was (18±2) Gy (1σ), and the coefficient of variability was 11.1%. Alanine dosimeters demonstrated easy handling, good precision and adequate sensitivity for this application

  7. Superhigh-frequency circuit for the EPR spectrometer with rectifier screening

    International Nuclear Information System (INIS)

    Zhizhchenko, G.A.; Tsvirko, L.V.

    1983-01-01

    The hamodyne SHF circuit of a 3-cm EPR spectrometer with a reflecting resonator is described. The optimum operating mode of SHF-rectifier at a constant phase difference is automatically assured in the circuit. The circuit employs a reflecting p-i-n- attenuator and a SHF-rectifier sereen which simplify the spectrometer tuming. The circuit is used in a miniature EPR radiospectrometer Minsk EPR-6-type

  8. Electret dosimeter utilizing gas multiplication

    International Nuclear Information System (INIS)

    Ikeya, M.; Miki, T.

    1980-01-01

    It was found that the high electric field around the surface of an electret leads to cascade multiplication of the ionization process in a surrounding gas. Very sensitive charge decay constants of the order of 1mrad, were obtained for electrets composed of polyvinyliden fluoride or teflon polymers. The reduced charge is stable and can be utilized in personnel dosimetry. A simple pocket chamber dosimeter is described consisting of a small speaker or buzzer, a cylindrical chamber filled with air, argon or other gases, a polymer thermoelectret foil and an electrode. The sonic vibration of the foil induces an alternating charge on the electrode which is amplified and detected. The feasibility of this dosimeter and its shock and vibration resistance have been demonstrated. (author)

  9. 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.

  10. Interpretation of the parameters of the EPR spectra of transition metal complexes

    International Nuclear Information System (INIS)

    Murav'ev, V.I.

    2005-01-01

    The calculated parameters of the EPR spectra of complexes of d 1 and d 9 ions, inclusive of MoOX 5 (X = Cl, Br), are reviewed. The covalent bond parameters used in the calculations were determined from EPR and experimental optical data (inverse problem of EPR spectroscopy). Various contributions to the expressions for the EPR parameters were compared. The observed abnormal values of the EPR parameters were discussed. The effects of charge-transfer states and the vibronic coupling on the components of g, A, and A L tensors were considered. Mechanisms of spin density transfer to ligands in paramagnetic complexes were proposed [ru

  11. Spin entanglement, decoherence and Bohm's EPR paradox.

    Science.gov (United States)

    Cavalcanti, E G; Drummond, P D; Bachor, H A; Reid, M D

    2009-10-12

    We obtain criteria for entanglement and the EPR paradox for spin-entangled particles and analyse the effects of decoherence caused by absorption and state purity errors. For a two qubit photonic state, entanglement can occur for all transmission efficiencies. In this case, the state preparation purity must be above a threshold value. However, Bohm's spin EPR paradox can be achieved only above a critical level of loss. We calculate a required efficiency of 58%, which appears achievable with current quantum optical technologies. For a macroscopic number of particles prepared in a correlated state, spin entanglement and the EPR paradox can be demonstrated using our criteria for efficiencies eta > 1/3 and eta > 2/3 respectively. This indicates a surprising insensitivity to loss decoherence, in a macroscopic system of ultra-cold atoms or photons.

  12. 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

  13. EPR becomes reality at Finland's Olkiluoto 3

    International Nuclear Information System (INIS)

    Gueldner, R.; Giese, U.

    2005-01-01

    The EPR is a third-generation pressurized water reactor (PWR). Its development was started in 1992 by Framatome and Siemens within a Franco-German partnership. Since 2001 this work has been continued by Framatome ANP, which was formed when the two companies merged their nuclear businesses. The French company AREVA, world market leader in nuclear technology, holds a 66% share in Framatome ANP, with Siemens owning 34%. From the very start, development of the EPR was focused on improving plant safety and economics even further. The new reactor development was jointly financed together with the leading power utilities of both countries. The first steps towards realization of an EPR nuclear power plant were taken at Olkiluoto, Finland in 2004, consisting of initial preparation of the construction site. By mid-February 2005 the local municipality - Eurajoki - had issued a construction permit, and the Finnish Government a construction license pursuant to the Finnish Nuclear Energy Act. This had been preceded by a preliminary safety assessment prepared by the Finnish Radiation and Nuclear Safety Authority (STUK) for the Finnish Ministry of Trade and Industry in which STUK verified that it did not see any safety-related issues opposing issuance of the nuclear construction license. STUK emphasized that the evolutionary design of the EPR had been further improved by AREVA compared to the previous product lines. Concreting work began this spring and the unit will start commercial operation in 2009. Construction of an EPR has also been given the political go-ahead in France. According to the utility Electricite de France (EDF) the new reactor will be built as a forerunner of a later series at the site of Flamanville in Normandy. Construction is scheduled to begin in 2007. An EPR nuclear power plant has a rated electric capacity of around 1600 MW, depending on specific site conditions. Being the product of intense bilateral cooperation the EPR combines the technological

  14. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

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

  16. Saturation recovery EPR spin-labeling method for quantification of lipids in biological membrane domains.

    Science.gov (United States)

    Mainali, Laxman; Camenisch, Theodore G; Hyde, James S; Subczynski, Witold K

    2017-12-01

    The presence of integral membrane proteins induces the formation of distinct domains in the lipid bilayer portion of biological membranes. Qualitative application of both continuous wave (CW) and saturation recovery (SR) electron paramagnetic resonance (EPR) spin-labeling methods allowed discrimination of the bulk, boundary, and trapped lipid domains. A recently developed method, which is based on the CW EPR spectra of phospholipid (PL) and cholesterol (Chol) analog spin labels, allows evaluation of the relative amount of PLs (% of total PLs) in the boundary plus trapped lipid domain and the relative amount of Chol (% of total Chol) in the trapped lipid domain [ M. Raguz, L. Mainali, W. J. O'Brien, and W. K. Subczynski (2015), Exp. Eye Res., 140:179-186 ]. Here, a new method is presented that, based on SR EPR spin-labeling, allows quantitative evaluation of the relative amounts of PLs and Chol in the trapped lipid domain of intact membranes. This new method complements the existing one, allowing acquisition of more detailed information about the distribution of lipids between domains in intact membranes. The methodological transition of the SR EPR spin-labeling approach from qualitative to quantitative is demonstrated. The abilities of this method are illustrated for intact cortical and nuclear fiber cell plasma membranes from porcine eye lenses. Statistical analysis (Student's t -test) of the data allowed determination of the separations of mean values above which differences can be treated as statistically significant ( P ≤ 0.05) and can be attributed to sources other than preparation/technique.

  17. Dosimetry for electron beam sterilization

    International Nuclear Information System (INIS)

    Miller, A.

    2007-01-01

    According to ISO 11137-1 (sect 4.3.4) dosimetry used in the development, validation and routine control of the sterilization process shall have measurement traceability to national or international standards and shall have a known level of uncertainty. It can only be obtained through calibration of the dosimeters. In presented lecture different types of dosimeter systems for electron beams (calorimeters, radiochromic film dosimeters, alanine / EPR) and their calibration are described

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-01-01

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

  19. Angular dependence of the nanoDot OSL dosimeter

    OpenAIRE

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

    2011-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-05-15

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

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  2. The measurement of oxygen in vivo using EPR techniques

    International Nuclear Information System (INIS)

    Swartz, Harold M.; Clarkson, Robert B.

    1998-01-01

    The measurement of pO 2 in vivo using EPR has some features which have already led to very useful applications and this approach is likely to have increasingly wide and effective use. It is based on the effect of oxygen on EPR spectra which provides a sensitive and accurate means to measure pO 2 quantitatively. The development of oxygen-sensitive paramagnetic materials which are very stable, combined with instrumental developments, has been crucial to the in vivo applications of this technique. The physical basis and biological applications of in vivo EPR oximetry are reviewed, with particular emphasis on the use of EPR spectroscopy at 1 GHz using particulate paramagnetic materials for the repetitive and non-invasive measurement of pO 2 in tissues. In vivo EPR has already produced some very useful results which have contributed significantly to solving important biological problems. The characteristics of EPR oximetry which appear to be especially useful are often complementary to existing techniques for measuring oxygen in tissues. These characteristics include the capability of making repeated measurements from the same site, high sensitivity to low levels of oxygen, and non-invasive options. The existing techniques are especially useful for studies in small animals, where the depth of measurements is not an overriding issue. In larger animals and potentially in human subjects, non-invasive techniques seem to be immediately applicable to study phenomena very near the surface (within 10 mm) while invasive techniques have some very promising uses. The clinical uses of EPR oximetry which seem especially promising and likely to be undertaken in the near future are long-term monitoring of the status and response to treatment of peripheral vascular disease and optimizing cancer therapy by enabling it to be modified on the basis of the pO 2 measured in the tumour. (author)

  3. Environmental monitoring by CaSO4:Dy TL dosimeters

    International Nuclear Information System (INIS)

    Deme, S.; Szabo, P.P.

    1975-12-01

    The thermoluminescent dosimeters of high sensitivity are useful for monitoring the area near nuclear installations. CaSO 4 :Dy TL dosimeters have high sensitivity and low fading so that by means of them the dose from the background can be measured with an accuracy of 10-20%. An increase of 2 mR in the background can be observed and doses as high as 1000R can be registered with an accuracy of 5%. The measuring method and results are reported here. For two years these CaSO 4 :Dy dosimeters have been successfully used at the site of the Central Research Institute for Physics. (K.A.)

  4. Toward 2D and 3D imaging of magnetic nanoparticles using EPR measurements.

    Science.gov (United States)

    Coene, A; Crevecoeur, G; Leliaert, J; Dupré, L

    2015-09-01

    Magnetic nanoparticles (MNPs) are an important asset in many biomedical applications. An effective working of these applications requires an accurate knowledge of the spatial MNP distribution. A promising, noninvasive, and sensitive technique to visualize MNP distributions in vivo is electron paramagnetic resonance (EPR). Currently only 1D MNP distributions can be reconstructed. In this paper, the authors propose extending 1D EPR toward 2D and 3D using computer simulations to allow accurate imaging of MNP distributions. To find the MNP distribution belonging to EPR measurements, an inverse problem needs to be solved. The solution of this inverse problem highly depends on the stability of the inverse problem. The authors adapt 1D EPR imaging to realize the imaging of multidimensional MNP distributions. Furthermore, the authors introduce partial volume excitation in which only parts of the volume are imaged to increase stability of the inverse solution and to speed up the measurements. The authors simulate EPR measurements of different 2D and 3D MNP distributions and solve the inverse problem. The stability is evaluated by calculating the condition measure and by comparing the actual MNP distribution to the reconstructed MNP distribution. Based on these simulations, the authors define requirements for the EPR system to cope with the added dimensions. Moreover, the authors investigate how EPR measurements should be conducted to improve the stability of the associated inverse problem and to increase reconstruction quality. The approach used in 1D EPR can only be employed for the reconstruction of small volumes in 2D and 3D EPRs due to numerical instability of the inverse solution. The authors performed EPR measurements of increasing cylindrical volumes and evaluated the condition measure. This showed that a reduction of the inherent symmetry in the EPR methodology is necessary. By reducing the symmetry of the EPR setup, quantitative images of larger volumes can be

  5. Toward 2D and 3D imaging of magnetic nanoparticles using EPR measurements

    International Nuclear Information System (INIS)

    Coene, A.; Crevecoeur, G.; Dupré, L.; Leliaert, J.

    2015-01-01

    Purpose: Magnetic nanoparticles (MNPs) are an important asset in many biomedical applications. An effective working of these applications requires an accurate knowledge of the spatial MNP distribution. A promising, noninvasive, and sensitive technique to visualize MNP distributions in vivo is electron paramagnetic resonance (EPR). Currently only 1D MNP distributions can be reconstructed. In this paper, the authors propose extending 1D EPR toward 2D and 3D using computer simulations to allow accurate imaging of MNP distributions. Methods: To find the MNP distribution belonging to EPR measurements, an inverse problem needs to be solved. The solution of this inverse problem highly depends on the stability of the inverse problem. The authors adapt 1D EPR imaging to realize the imaging of multidimensional MNP distributions. Furthermore, the authors introduce partial volume excitation in which only parts of the volume are imaged to increase stability of the inverse solution and to speed up the measurements. The authors simulate EPR measurements of different 2D and 3D MNP distributions and solve the inverse problem. The stability is evaluated by calculating the condition measure and by comparing the actual MNP distribution to the reconstructed MNP distribution. Based on these simulations, the authors define requirements for the EPR system to cope with the added dimensions. Moreover, the authors investigate how EPR measurements should be conducted to improve the stability of the associated inverse problem and to increase reconstruction quality. Results: The approach used in 1D EPR can only be employed for the reconstruction of small volumes in 2D and 3D EPRs due to numerical instability of the inverse solution. The authors performed EPR measurements of increasing cylindrical volumes and evaluated the condition measure. This showed that a reduction of the inherent symmetry in the EPR methodology is necessary. By reducing the symmetry of the EPR setup, quantitative images of

  6. Automated Calibration of Dosimeters for Diagnostic Radiology

    International Nuclear Information System (INIS)

    Romero Acosta, A.; Gutierrez Lores, S.

    2015-01-01

    Calibration of dosimeters for diagnostic radiology includes current and charge measurements, which are often repetitive. However, these measurements are usually done using modern electrometers, which are equipped with an RS-232 interface that enables instrument control from a computer. This paper presents an automated system aimed to the measurements for the calibration of dosimeters used in diagnostic radiology. A software application was developed, in order to achieve the acquisition of the electric charge readings, measured values of the monitor chamber, calculation of the calibration coefficient and issue of a calibration certificate. A primary data record file is filled and stored in the computer hard disk. The calibration method used was calibration by substitution. With this system, a better control over the calibration process is achieved and the need for human intervention is reduced. the automated system will be used in the calibration of dosimeters for diagnostic radiology at the Cuban Secondary Standard Dosimetry Laboratory of the Center for Radiation Protection and Hygiene. (Author)

  7. 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 biomolecules, the influence of a linker between the spin probe and biomolecule, and future opportunities.

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

    International Nuclear Information System (INIS)

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

    2014-08-01

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

  9. Anthracene dosimeter characterization under radiotherapy photons

    International Nuclear Information System (INIS)

    Czelusniak, Caroline

    2011-01-01

    New radiotherapy techniques such as intensity-modulated radiation therapy and stereotactic radiosurgery have increased the need for dosimeters that can provide measurements in real time with high spatial resolution. Organic scintillation dosimeters are able to measure with accuracy small radiation fields and fields with high gradients, besides having advantages such as water and soft tissue equivalence and the possibility to be used in vivo. Anthracene is an organic scintillator crystal with the highest known scintillation efficiency among organic scintillation materials. The objective of this work is to characterize the anthracene as a dosimeter under radiotherapy photons energies, analysing its signal against average granulosity, intern capsule diameter, absorbed dose, absorbed dose rate, photon energy and its spatial resolution; with the last one analysed under three methods (edge spread function, line spread function and modulation transfer function). The photons energies used were 1.25 MeV ( 60 Co), 0.661 MeV ( 137 Cs) and X-rays (effective energies of 28.4; 46.5; 48.5; 94.0 e 106.0 keV). The scintillation detection system consisted of an optical fiber with one end attached to the anthracene capsule and the other to a photomultiplier tube maintained by power supply followed by an electrometer. Once Cerenkov radiation occurs in the optical fiber, it was removed from the total scintillation signal trough the subtraction of the signal, taken irradiating the optical fiber without the anthracene attached to one of its extremity. From results obtained, one can infer that the dosimeter signal increases proportionally with average granulosity and intern capsule diameter. The signal is linearly dependent of absorbed dose, linearly dependent of low photons energies and independent for high photons energies, as well as independent of the absorbed dose rate. From the spatial resolution values obtained it was possible to infer that the one obtained through modulation

  10. Automatic dosimeter for kerma measurement based on commercial PIN photo diodes

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  11. Einstein and the Quantum: The Secret Life of EPR

    Science.gov (United States)

    Fine, Arthur

    2006-05-01

    Locality, separation and entanglement -- 1930s style. Starting with Solvay 1927, we'll explore the background to the 1935 paper by Einstein, Podolsky and Rosen: how it was composed, the actual argument and principles used, and how the paper was received by Schroedinger, and others. We'll also look at Bohr's response: the extent to which Bohr connects with what Einstein was after in EPR and the extent to which EPR marks a shift in Bohr's thinking about the quantum theory. Time permitting, we will contrast EPR with Bell's theorem.

  12. Use of normoxic polymer gel dosimeters for measuring diagnostic doses on CT scanners

    International Nuclear Information System (INIS)

    Hill, B; Venning, A J; Baldock, C

    2004-01-01

    X-ray CT has been used to evaluate polymer gel dosimeters for dose response in the therapeutic dose range. This method of polymer gel dosimeter evaluation has been shown to be useful for instance in the comparison of complex sterotactic field distributions with treatment plans. Image averaging and subtraction techniques are used for noise reduction in polymer gel dosimeters resulting in the delivery of several CT slices across the polymer gel dosimeters. It was a logical progression to evaluate normoxic polymer gel dosimeters with optimized CT scanning protocols. During these investigations it was found that unirradiated regions in irradiated normoxic polymer gel dosimetry phantoms polymerised possibly as a result of the evaluation using CT. This prompted an investigation of the CT diagnostic dose response of the normoxic polymer gel dosimeter in order to determine the dose contribution when evaluated using a CT scanner. Having established that there was an effect on the normoxic polymer gel dosimeter when evaluating with a CT scanner the suitability of these gels in the determination of CT diagnostic dose measurement was further investigated

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-06-30

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

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

    International Nuclear Information System (INIS)

    Balasybrahmanyam, V.; Measures, M.P.

    1977-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-04-15

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

  17. The EPR - technology for the 3rd millennium

    International Nuclear Information System (INIS)

    Bernstrauch, O.; Dubois, F.

    2001-01-01

    This paper is a story of a successful Franco-German co-operation: the EPR project. It is a rundown of the history of the EPR, before a decision is made to launch the lead-unit construction. The EPR is expected to progressively replace the existing nuclear power plants when they will reach the end of their service life. It integrates the latest technological advances, especially in safety and operational aspects and comprises more than 30 years operating experience. Thus, the EPR combines the qualities of its predecessors, the French N4 and the German Konvoi. The safety of the EPR was maximized both to prevent hypothetical accidents - even severe ones - and to reduce their consequences (corium spreading area, pre-stressed double containment with local liner, four-train safety systems...). The n+2 strategy (in the event of a problem with one train and even if a second train is undergoing maintenance, the remaining two are sufficient to perform the function) allows to perform maintenance during operation which leads consequently to short outage periods, highest availabilities and economical operation. Moreover, most of the EPR components are the result of mastered evolution. The reactor vessel, as a key element for the reactor service life, is designed to be in service for 60 years, the core is large (241 fuel elements instead of 205 in the N4 or 193 in the Konvoi) and the steam generators have higher efficiency. Along the same line, the core and core barrel design have been modified to allow a reduced uranium enrichment and the increase to 65 Gigawatt-day per metric-ton of the fuel discharge burn-up. Finally, the instrumentation and control systems minimize human error by giving the operators a grace period of at least 30 minutes to make decisions. (authors)

  18. EPR spectroscopy of spices

    Directory of Open Access Journals (Sweden)

    R. T. Тimakova

    2016-01-01

    Full Text Available From 01 January 2017 you enter the interstate standard GOST 33271-2015 “Dry Spices, herbs and vegetable seasonings. Manual exposure in order to combat pathogens and other microorganisms” which States that the absorbed dose of radiation to the spices should be from 3 to 30 kGy. The study found that before the introduction of permissive legislative framework in the consumer market of Russia there are irradiated food products (chili, ground chili, ground spicy chili, black pepper. For radiation monitoring of food safety, we used the method of electron paramagnetic resonance (EPR, which allows quickly and with a high degree of reliability to establish the fact of irradiation. It is established that all samples of spices irradiated with dose of 12 kGy (technology radappertization gave typical spectra of the signals established by the method of electron paramagnetic resonance in the domestic EPR spectrometer, the intensity, amplitude and peak width of the EPR signal of samples of spices with the increase of irradiation dose increases. It is proven that repeated exposure no effect accumulation. Integration with 2017 Russia in the global practi ce of using radiation technologies of processing of food products and food raw materials with the purpose of extending shelf life confirms the need for a data Bank on the radiation sensitivity of various food products to determine the optimal doses and the eff ect of radiation doses on the shelf life and quality of products.

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

    International Nuclear Information System (INIS)

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

    1991-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-12-01

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

  2. High dose potassium-nitrate chemical dosimeter

    International Nuclear Information System (INIS)

    Dorda de Cancio, E.M.; Munoz, S.S.

    1982-01-01

    This dosimeter is used to control 10 kGY-order doses (1 Mrad). Nitrate suffers a radiolitic reduction phenomena, which is related to the given dose. The method to use potassium nitrate as dosimeter is described, as well as effects of the temperature of irradiation, pH, nitrate concentration and post-irradiation stability. Nitrate powder was irradiated at a Semi-Industrial Plant, at Centro Atomico Ezeiza, and also in a Gammacell-220 irradiator. The dose rates used were 2,60 and 1,80 KGY/hour, and the given doses varied between 1,0 and 150 KGY. The uncertainty was +-3% in all the range. (author) [es

  3. Self-testing through EPR-steering

    International Nuclear Information System (INIS)

    Šupić, Ivan; Hoban, Matty J

    2016-01-01

    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. (paper)

  4. Thermoluminescence dosimeter reader

    International Nuclear Information System (INIS)

    Robertson, M.E.A.; Marshall, J.; Brabants, J.A.P.; Davies, M.E.

    1975-01-01

    An electric circuit arrangement is described including a photomultiplier tube and a high voltage source therefor also includes a feedback loop from the output of the tube to the high voltage source, and loop providing automatic gain stabilization for the tube. The arrangement is used in a dosimeter reader to provide sensitivity correction for the reader each time the reader is to be used

  5. Optical dosimeter

    International Nuclear Information System (INIS)

    Drukaroff, I.; Fishman, R.

    1984-01-01

    A reflecting optical dosimeter is a thin block of optical material having an input light pipe at one corner and an output light pipe at another corner, arranged so that the light path includes several reflections off the edges of the block to thereby greatly extend its length. In a preferred embodiment, one corner of the block is formed at an angle so that after the light is reflected several times between two opposite edges, it is then reflected several more times between the other two edges

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  7. EPR spectra induced by gamma-irradiation of some dry medical herbs

    Science.gov (United States)

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

    2009-04-01

    The radiation-induced EPR spectra in some medical herbs are reported. The samples studied are: (i) leaves of nettle, common balm, peppermint and thyme; (ii) stalks of common balm, thyme, milfoil, yarrow and marigold; (iii) blossoms of yarrow and marigold; (iv) blossoms and leaves of hawthorn and tutsan; and (v) roots of common valerian, nettle, elecampane (black and white), restharrows and carlina. Before irradiation all samples exhibit one weak anisotropic singlet EPR line with effective g-value of 2.0050±0.0002. The radiation-induced spectra fall into three groups. EPR spectra of irradiated blossoms of yarrow and marigold, stalks of common balm, thyme, tutsan and yarrow as well as roots of common valerian, nettle and elecampane (black and white) show "cellulose-like" EPR spectrum typical for irradiated plants. It is characterized by one intense central line with g=2.0050±0.0005 and two weak satellite lines situated ca. 30 G left and right to it. EPR spectra of gamma-irradiated restharrows and carlina are complex. They may be represented by one triplet corresponding to the "cellulose-like" EPR spectrum, one relatively intense singlet, situated in the center of the spectrum, and five weak additional satellite lines left and right to the center. The last spectrum was assigned as "carbohydrate-like" type. Only one intense EPR singlet with g=2.0048±0.0005 was recorded after irradiation of leaves of nettle and common balm. The lifetime of the radiation-induced EPR spectra was followed for a period of 3 months.

  8. EPR spectra induced by gamma-irradiation of some dry medical herbs

    International Nuclear Information System (INIS)

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

    2009-01-01

    The radiation-induced EPR spectra in some medical herbs are reported. The samples studied are: (i) leaves of nettle, common balm, peppermint and thyme; (ii) stalks of common balm, thyme, milfoil, yarrow and marigold; (iii) blossoms of yarrow and marigold; (iv) blossoms and leaves of hawthorn and tutsan; and (v) roots of common valerian, nettle, elecampane (black and white), restharrows and carlina. Before irradiation all samples exhibit one weak anisotropic singlet EPR line with effective g-value of 2.0050±0.0002. The radiation-induced spectra fall into three groups. EPR spectra of irradiated blossoms of yarrow and marigold, stalks of common balm, thyme, tutsan and yarrow as well as roots of common valerian, nettle and elecampane (black and white) show 'cellulose-like' EPR spectrum typical for irradiated plants. It is characterized by one intense central line with g=2.0050±0.0005 and two weak satellite lines situated ca. 30 G left and right to it. EPR spectra of gamma-irradiated restharrows and carlina are complex. They may be represented by one triplet corresponding to the 'cellulose-like' EPR spectrum, one relatively intense singlet, situated in the center of the spectrum, and five weak additional satellite lines left and right to the center. The last spectrum was assigned as 'carbohydrate-like' type. Only one intense EPR singlet with g=2.0048±0.0005 was recorded after irradiation of leaves of nettle and common balm. The lifetime of the radiation-induced EPR spectra was followed for a period of 3 months

  9. EPR spectra induced by gamma-irradiation of some dry medical herbs

    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; Lagunov, O. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Dimov, K. [Institute of Cryobiology and Food technology, 1162 Sofia (Bulgaria)

    2009-04-15

    The radiation-induced EPR spectra in some medical herbs are reported. The samples studied are: (i) leaves of nettle, common balm, peppermint and thyme; (ii) stalks of common balm, thyme, milfoil, yarrow and marigold; (iii) blossoms of yarrow and marigold; (iv) blossoms and leaves of hawthorn and tutsan; and (v) roots of common valerian, nettle, elecampane (black and white), restharrows and carlina. Before irradiation all samples exhibit one weak anisotropic singlet EPR line with effective g-value of 2.0050{+-}0.0002. The radiation-induced spectra fall into three groups. EPR spectra of irradiated blossoms of yarrow and marigold, stalks of common balm, thyme, tutsan and yarrow as well as roots of common valerian, nettle and elecampane (black and white) show 'cellulose-like' EPR spectrum typical for irradiated plants. It is characterized by one intense central line with g=2.0050{+-}0.0005 and two weak satellite lines situated ca. 30 G left and right to it. EPR spectra of gamma-irradiated restharrows and carlina are complex. They may be represented by one triplet corresponding to the 'cellulose-like' EPR spectrum, one relatively intense singlet, situated in the center of the spectrum, and five weak additional satellite lines left and right to the center. The last spectrum was assigned as 'carbohydrate-like' type. Only one intense EPR singlet with g=2.0048{+-}0.0005 was recorded after irradiation of leaves of nettle and common balm. The lifetime of the radiation-induced EPR spectra was followed for a period of 3 months.

  10. Case Studies in e-RPL and e-PR

    Science.gov (United States)

    Cameron, Roslyn; Miller, Allison

    2014-01-01

    The use of ePortfolios for recognition of prior learning (e-RPL) and for professional recognition (e-PR) is slowly gaining in popularity in the VET sector however their use is sporadic across educational sectors, disciplines, educational institutions and professions. Added to this is an array of purposes and types of e-RPL and e-PR models and…

  11. Response characteristics of selected personnel neutron dosimeters

    International Nuclear Information System (INIS)

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

    1983-09-01

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

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

    DEFF Research Database (Denmark)

    Simonsen, Jesper; Hertzum, Morten

    2006-01-01

    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...... 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....

  13. EPR study of interactions in the MoOCl3 - diethyl dithiophosphate - diethylamine system

    International Nuclear Information System (INIS)

    Larin, G.M.; Minin, V.V.

    2004-01-01

    By the method of EPR in MoOCl 3 -DDFH-DEta system when reagents ration is 1:1:>3 formation of a new molybdenum(V) imidocomplex in situ solution is detected. Composition and structure of a new molybdenum(V) imidocomplex - composition is MoNRCl(DDF) 3 (DDFH), coordination number is 7, structure is pentagonal bipyramid - are determined using analysis of additional superfine structure from atoms of ligands forming coordination sphere of molybdenum(V) imidocomplex [ru

  14. 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 (ΔB pp ) 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 (ΔB pp ) increased with increase in microwave power. EPR spectroscopy is useful to examine free radicals to optimize sterilization process and storage conditions of ophthalmologic samples.

  15. Free-radical probes for functional in vivo EPR imaging

    Science.gov (United States)

    Subramanian, S.; Krishna, M. C.

    2007-02-01

    Electron paramagnetic resonance imaging (EPRI) is one of the recent functional imaging modalities that can provide valuable in vivo physiological information on its own merit and aids as a complimentary imaging technique to MRI and PET of tissues especially with respect to in vivo pO II (oxygen partial pressure), redox status and pharmacology. EPR imaging mainly deals with the measurement of distribution and in vivo dynamics and redox changes using special nontoxic paramagnetic spin probes that can be infused into the object of investigation. These spin probes should be characterized by simple EPR spectra, preferably with narrow EPR lines. The line width should be reversibly sensitive to the concentration of in vivo pO II with a linear dependence. Several non-toxic paramagnetic probes, some particulate and insoluble and others water-soluble and infusible (by intravenous or intramuscular injection) have been developed which can be effectively used to quantitatively assess tissue redox status, and tumor hypoxia. Quantitative assessment of the redox status of tissue in vivo is important in investigating oxidative stress, and that of tissue pO II is very important in radiation oncology. Other areas in which EPR imaging and oxymetry may help are in the investigation of tumorangiogenesis, wound healing, oxygenation of tumor tissue by the ingestion of oxygen-rich gases, etc. The correct choice of the spin probe will depend on the modality of measurement (whether by CW or time-domain EPR imaging) and the particular physiology interrogated. Examples of the available spin probes and some EPR imaging applications employing them are presented.

  16. Evaluation of performance of metal oxide-silicon semiconductor field effect transistor (MOSFET) dosimeter

    International Nuclear Information System (INIS)

    Nagashima, Hiroyuki; Sano, Naoki; Nakamura, Osamu

    2001-01-01

    The JARP level dosimeter is the most suitable for absorbed dose determination in radiotherapy because of its high accuracy. However, in measuring the dose of an extremely small field, a dosimeter with a smaller active region is required. The active region of the MOSFET dosimeter is very small, having a volume of just 0.02 mm 3 . In this study, we evaluated the performance of MOSFET dosimeters with two different sensitivities and examined the usefulness of the MOSFET dosimeter in stereotactic radiosurgery. Using the high-sensitivity MOSFET dosimeter, we were able to reduce the experimental error of absorbed dose (≤±1.8%), and, by correcting the sensitivity, we could use it as a field dosimeter. By turning detectors inside out, we could reduce directional dependence (≤±1.8%). Correction was necessary in the TMR determination because peak depth shifts according to the material of the detector. In the determination of the dose distribution in the penumbra, the resolution of the MOSFET detectors was equal to that of the diamond detector. In the determination of OPF for the extremely small field, better results were obtained with MOSFET than with other small detectors. The high-sensitivity MOSFET dosimeter could properly evaluate the dose of an extremely small field and will be useful in dosimetry of the maximum dose of the field center in stereotactic radiosurgery. (author)

  17. Confirmation of a second EPR to be built at Penly

    International Nuclear Information System (INIS)

    Anon.

    2009-01-01

    The French government has made public its decision to launch the construction of a second EPR in France. This EPR is planned to be built on the Penly site (northern region of France). EDF will manage this project but other investors like GDF-Suez are invited to participate. The construction works are planned to begin in 2012 for a commissioning in 2017. This reactor will be the fifth EPR being built in the world. (A.C.)

  18. SU-E-T-753: Three-Dimensional Dose Distributions of Incident Proton Particle in the Polymer Gel Dosimeter and the Radiochromic Gel Dosimeter: A Simulation Study with MCNP Code

    International Nuclear Information System (INIS)

    Park, M; Kim, G; Ji, Y; Kim, K; Park, S; Jung, H

    2015-01-01

    Purpose: The purpose of this study is to estimate the three-dimensional dose distributions in the polymer and the radiochromic gel dosimeter, and to identify the detectability of both gel dosimeters by comparing with the water phantom in case of irradiating the proton particles. Methods: The normoxic polymer gel and the LCV micelle radiochromic gel were used in this study. The densities of polymer and the radiochromic gel dosimeter were 1.024 and 1.005 g/cm 3 , respectively. The dose distributions of protons in the polymer and radiochromic gel were simulated using Monte Carlo radiation transport code (MCNPX, Los Alamos National Laboratory). The shape of phantom irradiated by proton particles was a hexahedron with the dimension of 12.4 × 12.4 × 15.0 cm 3 . The energies of proton beam were 50, 80, and 140 MeV energies were directed to top of the surface of phantom. The cross-sectional view of proton dose distribution in both gel dosimeters was estimated with the water phantom and evaluated by the gamma evaluation method. In addition, the absorbed dose(Gy) was also calculated for evaluating the proton detectability. Results: The evaluation results show that dose distributions in both gel dosimeters at intermediated section and Bragg-peak region are similar with that of the water phantom. At entrance section, however, inconsistencies of dose distribution are represented, compared with water. The relative absorbed doses in radiochromic and polymer gel dosimeter were represented to be 0.47 % and 2.26 % difference, respectively. These results show that the radiochromic gel dosimeter was better matched than the water phantom in the absorbed dose evaluation. Conclusion: The polymer and the radiochromic gel dosimeter show similar characteristics in dose distributions for the proton beams at intermediate section and Bragg-peak region. Moreover the calculated absorbed dose in both gel dosimeters represents similar tendency by comparing with that in water phantom

  19. Improvement in the accuracy of polymer gel dosimeters using scintillating fibers

    International Nuclear Information System (INIS)

    Tremblay, Nicolas M; Hubert-Tremblay, Vincent; Bujold, Rachel; Beaulieu, Luc; Lepage, Martin

    2010-01-01

    We propose a novel method for the absolute calibration of polyacrylamide gel (PAG) dosimeters with one or more reference scintillating fiber dosimeters inserted inside the gel. Four calibrated scintillating fibers were inserted into a cylindrical glass container filled with a PAG dosimeter irradiated with a wedge filtered 6 MV photon beam. Calibration curves using small glass vials containing the same gel as the cylindrical containers were used to obtain a first calibration curve. This calibration curve was then adjusted with the dose measured with one of the scintillating fibers in a low gradient part of the field using different approaches. Among these, it was found that a translation of the gel calibration curve yielded the highest accuracy with PAG dosimeters.

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

    DEFF Research Database (Denmark)

    Marsh, Derek

    2016-01-01

    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...... 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: T1 n = 1/Wn. Results are compared and contrasted...

  1. Synthesis and production of potassium dichromate as a secondary standard dosimeter; Investigation of its comparative properties with Fricke and clear perspex dosimeters in comprehensive dose mapping of IR-136 Gamma Irradiator

    International Nuclear Information System (INIS)

    Taimoori Seechani; Behzad.

    1995-01-01

    Measurement of the absorbed dose is the principle mode or means of quality control in various application of radiation processing. Specially, the cumulative absorbed dose and its variation in different density product boxes (dose mapping) are often required. Proper discharge of these task would require the use of dosimeters having sufficient degree of accuracy and precision. The secondary standard potassium dichromate dosimeter is synthesized for the first time in Iran. The properties of this dosimeter such as dose response, dose rate dependency, reproducibility, molar extinction coefficient, reduction yield and effect of silver ions on reduction yield of dosimetry solution, irradiation temperature effect as well as pre- and post-irradiation stability of the dosimetry solution have been studied. The comparison of the results of this work with that of the ASTM standard of potassium dichromate has shown very good agreement. The produced dichromate dosimeters were used for comprehensive dose mapping or commissioning of the IR-136 irradiator. The non-uniformity ratio and the isodose lines in various product densities in the IR-136 have been measured. Cumulative dose values were obtained for different rows and levels of the IR-136 irradiator system. The results of dichromate dosimetry, wherever possible, were compared with the response of Fricke and clear perspex dosimeters. At low dose values, the precision of this dosimeter was found to be better than the precision of clear perspex, but about the same as that of Fricke dosimeter. It is thus may be said that this dosimeter has combined the desirable properties of both dosimeter together

  2. Applications of EPR steering in quantum teleportation and NOON states

    Science.gov (United States)

    Zárate, Laura Rosales

    2018-04-01

    Einstein-Podolsky-Rosen (EPR) steering refers to the type of correlations described in the EPR paradox, where one observer seems to affect ("steer") the state of other observer by using local measurements. There have been several works regarding characterization and quantification of EPR steering. One characteristic of this non-local correlation is that it can be asymmetric, while entanglement is symmetric. This asymmetric property is relevant for potential applications of EPR steering to quantum information, in particular to quantum cryptography and quantum teleportation. This latter refers to the process where one observer sends an unknown quantum state to Bob, who is in a different location. They communicate by classical means. Here we will show that EPR steering is a necessary resource to obtain secure continuous variable teleportation. We will also consider NOON states, which is an example of an entangled state. For this state, we will present a steering signature. This contribution reviews the work derived in Refs. [1] and [2], which was presented as an invited talk in ELAF 2017.

  3. The use of deciduous molars in EPR dose reconstruction

    International Nuclear Information System (INIS)

    El-faramawy, N.A.; Wieser, A.

    2005-01-01

    The use of deciduous teeth in EPR dose reconstruction has the unique potential to measure individual doses that were accumulated in the early childhood in the age up to 12 years. It was found previously that due to the small size of deciduous incisors, the available amount of enamel is not sufficient for EPR measurements. Therefore, dose assessment with deciduous incisors can only be done by measurement of whole teeth, including enamel and dentine. The measurement of whole teeth instead of enamel alone is possibly less reliable for dose reconstruction because the stability of CO 2 - radicals (that are an indicator for the absorbed dose) in biologically active dentine is not known. In the present study naturally loosed deciduous molars were investigated. The feasibility of separating enamel from small size molars was analysed. EPR spectrum parameters of whole molars and separated enamel only were evaluated before and after laboratory irradiation. The EPR signal amplitudes of the CO 2 - and native signals were determined by spectrum deconvolution, in dependence on radiation dose in the range 0.1 - 10 Gy. The fading at room temperature of native and CO 2 - EPR signals was analysed. The detection threshold for absorbed dose in enamel was determined.

  4. Spin entanglement, decoherence and Bohm's EPR paradox

    OpenAIRE

    Cavalcanti, E. G.; Drummond, P. D.; Bachor, H. A.; Reid, M. D.

    2007-01-01

    We obtain criteria for entanglement and the EPR paradox for spin-entangled particles and analyse the effects of decoherence caused by absorption and state purity errors. For a two qubit photonic state, entanglement can occur for all transmission efficiencies. In this case, the state preparation purity must be above a threshold value. However, Bohm's spin EPR paradox can be achieved only above a critical level of loss. We calculate a required efficiency of 58%, which appears achievable with cu...

  5. Study on the EPR/dosimetric properties of some substituted alanines

    International Nuclear Information System (INIS)

    Gancheva, Veselka; Sagstuen, Einar; Yordanov, Nicola D.

    2006-01-01

    Polycrystalline phenyl-alanine and perdeuterated l-α-alanine (l-α-alanine-d 4 ) were studied as potential high-energy radiation-sensitive materials (RSM) for solid state/EPR dosimetry. It was found that phenyl-alanine exhibits a linear dose response in the dose region 0.1-17kGy. However, phenyl-alanine is about 10 times less sensitive to γ-irradiation than standard l-α-alanine irradiated at the same doses. Moreover, the EPR response from phenyl-alanine is unstable and, independent of the absorbed dose, decreases by about 50% within 20 days after irradiation upon storage at room temperature. γ-irradiated polycrystalline perdeuterated l-α-alanine (CD 3 CD(NH 2 )COOH) has not previously been studied at room temperature by EPR spectroscopy. The first part of the present analysis was with respect to the structure of the EPR spectrum. By spectrum simulations, the presence of at least two radiation induced free radicals, R 1 =CH 3 C*(H)COOH and R 2 =H 3 N + -C*(CH 3 )COO - , was confirmed very clearly. Both these radicals were suggested previously from EPR and ENDOR studies of standard alanine crystals. The further investigations into the potential use of alanine-d 4 as RSM, after choosing optimal EPR spectrometer settings parameters for this purpose, show that it is ca. two times more sensitive than standard l-α-alanine

  6. Emergency EPR and OSL dosimetry with table vitamins and minerals.

    Science.gov (United States)

    Sholom, S; McKeever, S W S

    2016-12-01

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

  7. Comparison of continuous wave, spin echo, and rapid scan EPR of irradiated fused quartz

    International Nuclear Information System (INIS)

    Mitchell, Deborah G.; Quine, Richard W.; Tseitlin, Mark; Meyer, Virginia; Eaton, Sandra S.; Eaton, Gareth R.

    2011-01-01

    The E' defect in irradiated fused quartz has spin lattice relaxation times (T 1 ) about 100-300 μs and spin-spin relaxation times (T 2 ) up to about 200 μs, depending on the concentration of defects and other species in the sample. These long relaxation times make it difficult to record an unsaturated continuous wave (CW) electron paramagnetic resonance (EPR) signal that is free of passage effects. Signals measured at X-band (∼9.5 GHz) by three EPR methods: conventional slow-scan field-modulated EPR, rapid scan EPR, and pulsed EPR, were compared. To acquire spectra with comparable signal-to-noise, both pulsed and rapid scan EPR require less time than conventional CW EPR. Rapid scan spectroscopy does not require the high power amplifiers that are needed for pulsed EPR. The pulsed spectra, and rapid scan spectra obtained by deconvolution of the experimental data, are free of passage effects.

  8. A Local Realistic Reconciliation of the EPR Paradox

    Science.gov (United States)

    Sanctuary, Bryan

    2014-03-01

    The exact violation of Bell's Inequalities is obtained with a local realistic model for spin. The model treats one particle that comprises a quantum ensemble and simulates the EPR data one coincidence at a time as a product state. Such a spin is represented by operators σx , iσy ,σz in its body frame rather than the usual set of σX ,σY ,σZ in the laboratory frame. This model, assumed valid in the absence of a measuring probe, contains both quantum polarizations and coherences. Each carries half the EPR correlation, but only half can be measured using coincidence techniques. The model further predicts the filter angles that maximize the spin correlation in EPR experiments.

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

    Science.gov (United States)

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

    2014-05-01

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

  10. Antibacterial ethylene propylene rubber impregnated with silver nanopowder: AgNP@EPR

    Directory of Open Access Journals (Sweden)

    Marzieh Miranzadeh

    2016-01-01

    Full Text Available Following our interest in reaching for a molded rubber article with possible detergent contact applications, durable silver nanopowder (AgNP is synthesized by arc discharge, then mixed with varying ratios of ethylene propylene rubber (EPR, affording novel AgNP@EPR nanocomposites. X-ray diffraction (XRD patterns of AgNP as well as AgNP@EPR show no trace of impurity, while scanning electron microscopy (SEM indicates an average diameter of 50 nm for the former. Transmission electron microscopy (TEM images while confirm the SEM results, show quite a few 5 nm AgNP particles lying beside some micro crumbs. Our DC arc discharge technique involves explosion of movable silver anode and static cathode by a current pulse between 5 to 10 A cm-2. A solution blending method is employed for preparation of AgNP@EPR nanocomposites. The AgNP is first dispersed in toluene using an ultrasonic homogenizer, and then thoroughly mixed with EPR in the same solvent whose removal gives nanocomposites of 2, 4, 6 and 8 vol% AgNP in EPR,  showing strong antibacterial activity against both Escherichia coli and Staphylococcus aureus.

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

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  12. Calibration of helical tomotherapy machine using EPR/alanine dosimetry.

    Science.gov (United States)

    Perichon, Nicolas; Garcia, Tristan; François, Pascal; Lourenço, Valérie; Lesven, Caroline; Bordy, Jean-Marc

    2011-03-01

    Current codes of practice for clinical reference dosimetry of high-energy photon beams in conventional radiotherapy recommend using a 10 x 10 cm2 square field, with the detector at a reference depth of 10 cm in water and 100 cm source to surface distance (SSD) (AAPM TG-51) or 100 cm source-to-axis distance (SAD) (IAEA TRS-398). However, the maximum field size of a helical tomotherapy (HT) machine is 40 x 5 cm2 defined at 85 cm SAD. These nonstandard conditions prevent a direct implementation of these protocols. The purpose of this study is twofold: To check the absorbed dose in water and dose rate calibration of a tomotherapy unit as well as the accuracy of the tomotherapy treatment planning system (TPS) calculations for a specific test case. Both topics are based on the use of electron paramagnetic resonance (EPR) using alanine as transfer dosimeter between the Laboratoire National Henri Becquerel (LNHB) 60Co-gamma-ray reference beam and the Institut Curie's HT beam. Irradiations performed in the LNHB reference 60Co-gamma-ray beam allowed setting up the calibration method, which was then implemented and tested at the LNHB 6 MV linac x-ray beam, resulting in a deviation of 1.6% (at a 1% standard uncertainty) relative to the reference value determined with the standard IAEA TRS-398 protocol. HT beam dose rate estimation shows a difference of 2% with the value stated by the manufacturer at a 2% standard uncertainty. A 4% deviation between measured dose and the calculation from the tomotherapy TPS was found. The latter was originated by an inadequate representation of the phantom CT-scan values and, consequently, mass densities within the phantom. This difference has been explained by the mass density values given by the CT-scan and used by the TPS which were not the true ones. Once corrected using Monte Carlo N-Particle simulations to validate the accuracy of this process, the difference between corrected TPS calculations and alanine measured dose values was then

  13. Alanine EPR dosimetry of therapeutic irradiators

    International Nuclear Information System (INIS)

    Bugay, O.; Bartchuk, V.; Kolesnik, S.; Mazin, M.; Gaponenko, H.

    1999-01-01

    The high-dose alanine EPR dosimetry is a very precise method in the dose range 1-100 kGy. The system is used generally as the standard high-dose transfer dosimetry in many laboratories. This is comparatively expensive technique so it is important to use it as a more universal dosimetry system also in the middle and low dose ranges. The problems of the middle-dose alanine dosimetry are discussed and the solution of several problems is proposed. The alanine EPR dosimetry has been applied to the dose measurements of medical irradiators in the Kiev City Oncology Center. (author)

  14. 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...

  15. EPR Study of [Cu(Him)4]·2Br Complex

    International Nuclear Information System (INIS)

    Yıldırım, İ; Karabulut, B

    2016-01-01

    The single crystal of [Cu(Him) 4 ]·2Br (Him: C 3 H 4 N 2 , imidazole) complex has been investigated at ambient temperature in three mutually perpendicular planes by EPR technique. The magnetic environments of [Cu(Him) 4 ]·2Br complex have been identified by EPR technique. The study reveals the existence of two magnetically inequivalent Cu 2+ sites. The principal values of g tensors were obtained. The EPR parameters show that the paramagnetic centers have rhombic symmetry. (paper)

  16. Pulse EPR distance measurements to study multimers and multimerisation

    Science.gov (United States)

    Ackermann, Katrin; Bode, Bela E.

    2018-06-01

    Pulse dipolar electron paramagnetic resonance (PD-EPR) has become a powerful tool for structural biology determining distances on the nanometre scale. Recent advances in hardware, methodology, and data analysis have widened the scope to complex biological systems. PD-EPR can be applied to systems containing lowly populated conformers or displaying large intrinsic flexibility, making them all but intractable for cryo-electron microscopy and crystallography. Membrane protein applications are of particular interest due to the intrinsic difficulties for obtaining high-resolution structures of all relevant conformations. Many drug targets involved in critical cell functions are multimeric channels or transporters. Here, common approaches for introducing spin labels for PD-EPR cause the presence of more than two electron spins per multimeric complex. This requires careful experimental design to overcome detrimental multi-spin effects and to secure sufficient distance resolution in presence of multiple distances. In addition to obtaining mere distances, PD-EPR can also provide information on multimerisation degrees allowing to study binding equilibria and to determine dissociation constants.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-09-01

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

  18. X-ray and EPR study of reactions between B4C and TiO2

    International Nuclear Information System (INIS)

    Kakazey, M.; Vlasova, M.; Gonzalez-Rodriguez, J.G.; Dominguez-Patino, M.; Leder, R.

    2006-01-01

    X-ray diffraction and electron paramagnetic resonance (EPR) methods have been used to study the reaction process in a system of 95 wt.% of B 4 C + 5 wt.% TiO 2 . The addition of TiO 2 to B 4 C was effective in accelerating the removal of carbon inclusions. Two types of reactions between B 4 C and TiO 2 , starting at temperatures ∼1173 K, took place: (a) gas-transport exchange and (b) diffusion of Ti atoms into the B 4 C lattice. These reactions modify the number and type of donor centers in the B 4 C. The dependence of EPR line width on the number of donor centers in B 4 C (from conditions of sample treatment) is a useful method for investigating the formation of powders and ceramics based on B 4 C

  19. EPR Imaging at a Few Megahertz Using SQUID Detectors

    Science.gov (United States)

    Hahn, Inseob; Day, Peter; Penanen, Konstantin; Eom, Byeong Ho

    2010-01-01

    An apparatus being developed for electron paramagnetic resonance (EPR) imaging operates in the resonance-frequency range of about 1 to 2 MHz well below the microwave frequencies used in conventional EPR. Until now, in order to obtain sufficient signal-to-noise radios (SNRs) in conventional EPR, it has been necessary to place both detectors and objects to be imaged inside resonant microwave cavities. EPR imaging has much in common with magnetic resonance imaging (MRI), which is described briefly in the immediately preceding article. In EPR imaging as in MRI, one applies a magnetic pulse to make magnetic moments (in this case, of electrons) precess in an applied magnetic field having a known gradient. The magnetic moments precess at a resonance frequency proportional to the strength of the local magnetic field. One detects the decaying resonance-frequency magnetic- field component associated with the precession. Position is encoded by use of the known relationship between the resonance frequency and the position dependence of the magnetic field. EPR imaging has recently been recognized as an important tool for non-invasive, in vivo imaging of free radicals and reduction/oxidization metabolism. However, for in vivo EPR imaging of humans and large animals, the conventional approach is not suitable because (1) it is difficult to design and construct resonant cavities large enough and having the required shapes; (2) motion, including respiration and heartbeat, can alter the resonance frequency; and (3) most microwave energy is absorbed in the first few centimeters of tissue depth, thereby potentially endangering the subject and making it impossible to obtain adequate signal strength for imaging at greater depth. To obtain greater penetration depth, prevent injury to the subject, and avoid the difficulties associated with resonant cavities, it is necessary to use lower resonance frequencies. An additional advantage of using lower resonance frequencies is that one can use

  20. Emergency Preservation and Resuscitation for Cardiac Arrest from Trauma (EPR-CAT)

    Science.gov (United States)

    2015-10-01

    Award Number: W81XWH-07-1-0682 TITLE: Emergency Preservation and Resuscitation for Cardiac Arrest from Trauma ( EPR -CAT) PRINCIPAL INVESTIGATOR...thoracotomy and open chest CPR, results in unacceptably low survival rates. Emergency Preservation and Resuscitation ( EPR ) was developed to rapidly preserve...further recommended that the trauma surgeons involved in the study obtain hospital privileges for cannulation for the EPR flush. This has been

  1. Emergency Preservation and Resuscitation for Cardiac Arrest from Trauma (EPR CAT)

    Science.gov (United States)

    2016-12-01

    Award Number: W81XWH-07-1-0682 TITLE: Emergency Preservation and Resuscitation for Cardiac Arrest from Trauma ( EPR -CAT) PRINCIPAL INVESTIGATOR...Preservation and Resuscitation ( EPR ) was developed to rapidly preserve the organism during ischemia, using hypothermia, drugs, and fluids, to “buy time...privileges for cannulation for the EPR flush. This has been accomplished. Given the complexity of our planned intervention for trauma patients in

  2. Optimal registration conditions for tooth EPR dosimetry at low accumulated dose

    International Nuclear Information System (INIS)

    Galtsev, V.E.; Galtseva, E.V.; Lebedev, Y.S.

    1997-01-01

    The spectrum registration under rapid passage conditions (the second harmonic phase quadrature of the absorption signal) allows one to enhance substantially the sensitivity of tooth enamel and bone EPR dosimetry at a low accumulated dose. In the present work the dependencies of the radiation and background signals on EPR spectrometer parameters are described and the optimal conditions in RPM for EPR dosimetry are obtained. (Author)

  3. Performances of Dose Measurement of Commercial Electronic Dosimeters using Geiger Muller Tube and PIN Diode

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Hyunjun; Kim, Chankyu; Kim, Yewon; Kim, Giyoon; Cho, Gyuseong [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    There are two categories in personal dosimeters, one is passive type dosimeter such as TLD (thermoluminescence dosimeter) and the other is active type dosimeter such as electronic dosimeter can show radiation dose immediately while TLD needs long time to readout its data by heating process. For improving the reliability of measuring dose for any energy of radiations, electronic dosimeter uses energy filter by metal packaging its detector using aluminum or copper, but measured dose of electronic dosimeter with energy filter cannot be completely compensated in wide radiation energy region. So, in this paper, we confirmed the accuracy of dose measurement of two types of commercial EPDs using Geiger Muller tube and PIN diode with CsI(Tl) scintillator in three different energy of radiation field. The experiment results for Cs-137 was almost similar with calculation value in the results of both electronic dosimeters, but, the other experiment values with Na-22 and Co-60 had higher error comparing with Cs-137. These results were caused by optimization of their energy filters. The optimization was depending on its thickness of energy filter. So, the electronic dosimeters have to optimizing the energy filter for increasing the accuracy of dose measurement or the electronic dosimeter using PIN diode with CsI(Tl) scintillator uses the multi-channel discriminator for using its energy information.

  4. 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.

  5. Wormhole and entanglement (non-)detection in the ER=EPR correspondence

    International Nuclear Information System (INIS)

    Bao, Ning; Pollack, Jason; 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.

  6. TH-CD-201-08: Flexible Dosimeter Bands for Whole-Body Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Kim, T; Fahimian, B; Pratx, G [Department of Radiation Oncology, Stanford University, Palo Alto, CA (United States)

    2016-06-15

    Purpose: The two commonly used radiotherapy techniques are total body irradiation (TBI) and the total skin irradiation (TSI). In order to ensure the accuracy of the prescription beams, the dose received throughout the entire body must be checked using dosimetry. However, the available number of data points is limited as the dosimeters are manually placed on the patient. We developed a flexible and wearable dosimeter that can collect 1D continuous dose information around the peripheral of the patients’ body, including areas obscured from the beam path. Methods: The flexible dosimeter bands are fabricated by embedding storage phosphor powders in a thin layer of non-toxic silicone based elastomer (PDMS). An additional elastomer layer is formed on top of the phosphor layer to provide additional mechanical support for the dosimeter. Once the curing process is complete, the dosimeter is cut into multiple bands and rolled into spools prior to use. Results: The dose responses are tested using a preclinical cabinet X-ray system, where the readout is performed with a storage phosphor reader. Results show that the dose calibration factor is ∼1400 (A.U./Gy) from the beam center. Also, 1-D dose distribution experiment was performed in water phantoms, where preliminary results demonstrate that the dose in water is indeed attenuated compared to in air. Conclusion: Dose response and high-resolution 1-D dosimetry is demonstrated using the flexible dosimeters. By providing a detailed spatial description of the beam dose profile, we expect that the dosimeter bands may aid in enhancing the current existing modality in dosimetry. Since the dosimeter is flexible (can retract back to its original length), they can be comfortably worn around the patient. Potentially, multiple 1-D dose information can be stitched together and extrapolated to provide a coarse 3-D image of the dose distribution. This work was supported by funding from the Cutaneous Lymphoma Foundation under the CLARIONS

  7. TH-CD-201-08: Flexible Dosimeter Bands for Whole-Body Dosimetry

    International Nuclear Information System (INIS)

    Kim, T; Fahimian, B; Pratx, G

    2016-01-01

    Purpose: The two commonly used radiotherapy techniques are total body irradiation (TBI) and the total skin irradiation (TSI). In order to ensure the accuracy of the prescription beams, the dose received throughout the entire body must be checked using dosimetry. However, the available number of data points is limited as the dosimeters are manually placed on the patient. We developed a flexible and wearable dosimeter that can collect 1D continuous dose information around the peripheral of the patients’ body, including areas obscured from the beam path. Methods: The flexible dosimeter bands are fabricated by embedding storage phosphor powders in a thin layer of non-toxic silicone based elastomer (PDMS). An additional elastomer layer is formed on top of the phosphor layer to provide additional mechanical support for the dosimeter. Once the curing process is complete, the dosimeter is cut into multiple bands and rolled into spools prior to use. Results: The dose responses are tested using a preclinical cabinet X-ray system, where the readout is performed with a storage phosphor reader. Results show that the dose calibration factor is ∼1400 (A.U./Gy) from the beam center. Also, 1-D dose distribution experiment was performed in water phantoms, where preliminary results demonstrate that the dose in water is indeed attenuated compared to in air. Conclusion: Dose response and high-resolution 1-D dosimetry is demonstrated using the flexible dosimeters. By providing a detailed spatial description of the beam dose profile, we expect that the dosimeter bands may aid in enhancing the current existing modality in dosimetry. Since the dosimeter is flexible (can retract back to its original length), they can be comfortably worn around the patient. Potentially, multiple 1-D dose information can be stitched together and extrapolated to provide a coarse 3-D image of the dose distribution. This work was supported by funding from the Cutaneous Lymphoma Foundation under the CLARIONS

  8. Clinical EPR: Unique Opportunities and Some Challenges

    Science.gov (United States)

    Swartz, Harold M.; Williams, Benjamin B.; Zaki, Bassem I.; Hartford, Alan C.; Jarvis, Lesley A.; Chen, Eunice; Comi, Richard J.; Ernstoff, Marc S.; Hou, Huagang; Khan, Nadeem; Swarts, Steven G.; Flood, Ann B.; Kuppusamy, Periannan

    2014-01-01

    Electron paramagnetic resonance (EPR) spectroscopy has been well established as a viable technique for measurement of free radicals and oxygen in biological systems, from in vitro cellular systems to in vivo small animal models of disease. However, the use of EPR in human subjects in the clinical setting, although attractive for a variety of important applications such as oxygen measurement, is challenged with several factors including the need for instrumentation customized for human subjects, probe and regulatory constraints. This paper describes the rationale and development of the first clinical EPR systems for two important clinical applications, namely, measurement of tissue oxygen (oximetry), and radiation dose (dosimetry) in humans. The clinical spectrometers operate at 1.2 GHz frequency and use surface loop resonators capable of providing topical measurements up to 1 cm depth in tissues. Tissue pO2 measurements can be carried out noninvasively and repeatedly after placement of an oxygen-sensitive paramagnetic material (currently India ink) at the site of interest. Our EPR dosimetry system is capable of measuring radiation-induced free radicals in the tooth of irradiated human subjects to determine the exposure dose. These developments offer potential opportunities for clinical dosimetry and oximetry, which include guiding therapy for individual patients with tumors or vascular disease, by monitoring of tissue oxygenation. Further work is in progress to translate this unique technology to routine clinical practice. PMID:24439333

  9. LLL development of a combined etch track: albedo dosimeter

    International Nuclear Information System (INIS)

    Griffith, R.V.; Fisher, J.C.; Harder, C.A.

    1977-01-01

    The addition of polycarbonate sheet to albedo detectors for electrochemical etching provides a simple, inexpensive way to reduce the spectral sensitivity of the personnel dosimeter without losing the albedo features of sensitivity and ease of automation. The ECEP technique also provides the dosimetrist with the potential for identifying conditions of body orientation that might otherwise lead to significant error in dosimeter evaluation

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

    DEFF Research Database (Denmark)

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

    1996-01-01

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

  11. Perspectives of shaped pulses for EPR spectroscopy

    Science.gov (United States)

    Spindler, Philipp E.; Schöps, Philipp; Kallies, Wolfgang; Glaser, Steffen J.; Prisner, Thomas F.

    2017-07-01

    This article describes current uses of shaped pulses, generated by an arbitrary waveform generator, in the field of EPR spectroscopy. We show applications of sech/tanh and WURST pulses to dipolar spectroscopy, including new pulse schemes and procedures, and discuss the more general concept of optimum-control-based pulses for applications in EPR spectroscopy. The article also describes a procedure to correct for experimental imperfections, mostly introduced by the microwave resonator, and discusses further potential applications and limitations of such pulses.

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  13. Dependencies of the radiation sensitivity of human tooth enamel in EPR dosimetry

    International Nuclear Information System (INIS)

    Wieser, A.; El-Faramawy, N.; Meckbach, R.

    2001-01-01

    The EPR dose response of tooth enamel was determined for human molars collected in Egypt. The influence of age, gender and residence of the tooth donors as well as tooth position and sample preparation on EPR sensitivity and its variability over the enamel samples was investigated. The EPR sensitivity and its variability were found to depend only on the sample preparation procedure. The variability in EPR sensitivity of enamel from Egyptian teeth was maximally 10% and the mean sensitivity was in good agreement with that of German teeth

  14. Development of colored alumilite dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Obara, Kenjiro; Shibanuma, Kiyoshi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Yagi, Toshiaki [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Yokoo, Noriko [Radiation Application Development Association, Tokai, Ibaraki (Japan)

    2003-03-01

    In the ITER (International Thermonuclear Experimental Reactor), in-vessel components such as blanket and divertor, which are installed in the vacuum vessel of the ITER, are maintained by remote handling equipment (RH equipment). The RH equipment for maintenance is operated under sever environmental conditions, such as high temperature (50{approx}100 degC), high gamma-ray radiation ({approx}1 kGy/h) in an atmosphere of inert gas or vacuum; therefore many components of the RH equipment must have a suitable radiation resistance efficiency for long time operation (10{approx}100 MGy). Typical components of the RH equipment have been extensively tested under an intensive gamma-ray radiation. Monitoring of the radiation dose of the components of the RH equipment is essential to control the operation period of the RH equipment considering radiation resistance. However, the maximum measurable radiation dose of the conventional dosimeters, such as ionization chamber, liquid, glass and plastic dosimeters are limited to be approximately 1MGy which is too low to monitor the RH equipment for the ITER. In addition, these conventional dosimeters do not involve sufficient radiation resistance against the high gamma-ray radiation as well as are not easy handling and low cost. Based on the above backgrounds, a new dosimeter with bleaching of an azo group dye to be applied to a radiation monitor has been developed for high gamma-ray radiation use. The colored alumilite dosimeter is composed of the azo group dye (-N=N-) in an anodic oxidation layer of aluminum alloy (Al{sub 2}O{sub 3}). It can monitor the radiation dose by measuring the change of the bleaching of azo dye in the Al{sub 2}O{sub 3} layer due to gamma-ray irradiation. The degree of bleaching is measured as the change of hue (color) and brightness based on the Munsell's colors with a three dimensional universe using spectrophotometer. In the tests, the dependencies such as colors, anodized layer thickness, type of azo

  15. Estimation of personal dose based on the dependent calibration of personal dosimeters in interventional radiology

    International Nuclear Information System (INIS)

    Mori, Hiroshige; Koshida, Kichiro; Ichikawa, Katsuhiro

    2007-01-01

    The purpose of present study is, in interventional radiology (IVR), to elucidate the differences between each personal dosimeter, and the dependences and calibrations of area or personal dose by measurement with electronic dosimeters in particular. We compare space dose rate distributions measured by an ionization survey meter with the value measured by personal dosimeter: an optically stimulated luminescence, two fluoroglass, and two electronic dosimeters. Furthermore, with electronic dosimeters, we first measured dose rate, energy, and directional dependences. Secondly, we calibrated the dose rate measured by electronic dosimeters with the results, and estimated these methods with coefficient of determination and Akaike's Information Criterion (AIC). The results, especially in electronic dosimeters, revealed that the dose rate measured fell by energy and directional dependences. In terms of methods of calibration, the method is sufficient for energy dependence, but not for directional dependence, because of the lack of stable calibration. This improvement poses a question for the future. The study suggested that these dependences of the personal dosimeter must be considered when area or personal dose is estimated in IVR. (author)

  16. Saturation transfer EPR (ST-EPR) for dating biocarbonates containing large amount of Mn2+: separation of SO3- and CO2- lines and geochronology of Brazilian fish fossil

    International Nuclear Information System (INIS)

    Sastry, M.D.; Andrade, M.B.; Watanabe, Shigueo

    2003-01-01

    A method using saturation transfer EPR (ST-EPR) is shown to be feasible for detecting EPR signal of radiation-induced defects in biocarbonates containing large amount of Mn 2+ . The ST-EPR measurements conducted at room temperature on fish fossil of Brazilian origin, enabled the identification of CO 2 - and SO 3 - radical ions, by partially suppressing the intense signal from Mn 2+ when the signal are detected 90 deg. out of phase with magnetic field modulating signal and at high microwave power (50 mW). Using these signals the age of fish fossil is estimated to be (36±5) Ma

  17. Investigating Pigment Radicals in Black Rice Using HPLC and Multi-EPR.

    Science.gov (United States)

    Nakagawa, Kouichi; Maeda, Hayato

    2017-01-01

    We investigated the location and distribution of paramagnetic species in black and white rice using electron paramagnetic resonance (EPR), X-band (9 GHz) EPR imaging (EPRI), and HPLC. EPR primarily detected two paramagnetic species in black rice, which were identified as a stable radical and Mn 2+ species, based on the g values and hyperfine components of the EPR signals. The signal from the stable radical appeared at g ≈ 2.00 and was relatively strong and stable. Subsequent noninvasive two-dimensional (2D) EPRI revealed that this stable radical was primarily located in the pigmented region of black rice, while very few radicals were observed in the rice interior. Pigments extracted from black rice were analyzed using HPLC; the major compound was found to be cyanidin-3-glucoside. EPR and HPLC results indicate that the stable radical was only found within the pigmented region of the rice, and that it could either be cyanidin-3-glucoside, or one of its oxidative decomposition products.

  18. MO-AB-BRA-04: Radiation Measurements with a DNA Double-Strand-Break Dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Obeidat, M; Cline, K; Stathakis, S; Papanikolaou, N; Rasmussen, K; Gutierrez, A; Ha, CS; Lee, SE; Shim, EY; Kirby, N [University of Texas HSC SA, San Antonio, TX (United States)

    2016-06-15

    Purpose: Many types of dosimeters are used to measure radiation, but none of them directly measures the biological effect of this dose. The purpose here is to create a dosimeter that can measure the probability of double-strand breaks (DSB) for DNA, which is directly related to the biological effect of radiation. Methods: The dosimeter has DNA strands, which are labeled on one end with biotin and on the other with fluorescein. The biotin attaches these strands to magnetic beads. We suspended the DNA dosimeter in phosphate-buffered saline (PBS) as it matches the internal environment of the body. We placed small volumes (50µL) of the DNA dosimeter into tubes and irradiated these samples in a water-equivalent plastic phantom with several doses (three samples per dose). After irradiating the samples, a magnet was placed against the tubes. The fluorescein attached to broken DNA strands was extracted (called the supernatant) and placed into a different tube. The fluorescein on the unbroken strands remained attached to the beads in the tube and was re-suspended with 50µL of PBS. A fluorescence reader was used to measure the fluorescence for both the re-suspended beads and supernatant. To prove that we are measuring DSB, we tested dosimeter response with two different lengths of attached DNA strands (1 and 4 kilo-base pair). Results: The probability of DSB at the dose levels of 5, 10, 25, and 50 Gy were 0.05, 0.08, 0.12, and 0.19, respectively, while the coefficients of variation were 0.14, 0.07, 0.02, and 0.01, respectively. The 4 kilo-base-pair dosimeter produced 5.3 times the response of the 1 kilo-base-pair dosimeter. Conclusion: The DNA dosimeter yields a measurable response to dose that scales with the DNA strand length. The goal now is to refine the dosimeter fabrication to reproducibly create a low coefficient of variation for the lower doses. This work was supported in part by Yarmouk University (Irbid, Jordan) and CPRIT (RP140105)

  19. MO-AB-BRA-04: Radiation Measurements with a DNA Double-Strand-Break Dosimeter

    International Nuclear Information System (INIS)

    Obeidat, M; Cline, K; Stathakis, S; Papanikolaou, N; Rasmussen, K; Gutierrez, A; Ha, CS; Lee, SE; Shim, EY; Kirby, N

    2016-01-01

    Purpose: Many types of dosimeters are used to measure radiation, but none of them directly measures the biological effect of this dose. The purpose here is to create a dosimeter that can measure the probability of double-strand breaks (DSB) for DNA, which is directly related to the biological effect of radiation. Methods: The dosimeter has DNA strands, which are labeled on one end with biotin and on the other with fluorescein. The biotin attaches these strands to magnetic beads. We suspended the DNA dosimeter in phosphate-buffered saline (PBS) as it matches the internal environment of the body. We placed small volumes (50µL) of the DNA dosimeter into tubes and irradiated these samples in a water-equivalent plastic phantom with several doses (three samples per dose). After irradiating the samples, a magnet was placed against the tubes. The fluorescein attached to broken DNA strands was extracted (called the supernatant) and placed into a different tube. The fluorescein on the unbroken strands remained attached to the beads in the tube and was re-suspended with 50µL of PBS. A fluorescence reader was used to measure the fluorescence for both the re-suspended beads and supernatant. To prove that we are measuring DSB, we tested dosimeter response with two different lengths of attached DNA strands (1 and 4 kilo-base pair). Results: The probability of DSB at the dose levels of 5, 10, 25, and 50 Gy were 0.05, 0.08, 0.12, and 0.19, respectively, while the coefficients of variation were 0.14, 0.07, 0.02, and 0.01, respectively. The 4 kilo-base-pair dosimeter produced 5.3 times the response of the 1 kilo-base-pair dosimeter. Conclusion: The DNA dosimeter yields a measurable response to dose that scales with the DNA strand length. The goal now is to refine the dosimeter fabrication to reproducibly create a low coefficient of variation for the lower doses. This work was supported in part by Yarmouk University (Irbid, Jordan) and CPRIT (RP140105)

  20. Thermodynamic Basis of Electron Transfer in Dihydroorotate Dehydrogenase B from Lactococcus lactis:  Analysis by Potentiometry, EPR Spectroscopy, and ENDOR Spectroscopy

    DEFF Research Database (Denmark)

    Mohnsen, Al-Walid A.; Rigby, Stephen E. J.; Jensen, Kaj Frank

    2004-01-01

    Dihydroorotate dehydrogenase B (DHODB) is a complex iron-sulfur flavoprotein that catalyzes the conversion of dihydroorotate to orotate and the reduction of NAD+. The enzyme is a dimer of heterodimers containing an FMN, an FAD, and a 2Fe-2S center. UV-visible, EPR, and ENDOR spectroscopies have...... similar to those recorded for the blue semiquinone of free flavins in aqueous solution, thus confirming the presence of this species in DHODB. Spectral features observed during EPR spectroscopy of dithionite-reduced DHODB are consistent with the midpoint reduction potentials determined using UV-visible...... spectroscopy and further identify an unusual EPR signal with very small rhombic anisotropy and g values of 2.02, 1.99, and 1.96. This unusual 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...