Progress in quality control of alanine dosimeters

Dolo, Jean‐Michel; Lecerf, N.; Tartès, I.

doi:10.1016/s0969-8043(96)00204-7

Cited by 10 publications

(5 citation statements)

References 5 publications

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“…Thin alanine dosimeters (1-2.5 mm thick) with a mass comparable with that of the ammonium tartrate dosimeters discussed in this paper have a minimum measurable dose of at least 3 Gy (De Angelis et al 2000, Dolo et al 1996, Gohs 1996, Sharpe et al 1996. Ammonium tartrate therefore seems to have a higher sensitivity than alanine and other materials used for ESR dosimeters (Azorín et al 2000, Hassan et al 1998, Yavuz and Köksal 1999 if results concerning samples with equal mass are examined.…”

Section: Dose Response and Background Signalmentioning

confidence: 77%

Response characterization of ammonium tartrate solid state pellets for ESR dosimetry with radiotherapeutic photon and electron beams

et al. 2001

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Solid state pellets (1 mm thick) for electron spin resonance (ESR) dosimetry were made using ammonium tartrate as the radiation-sensitive substance. Their behaviour was experimentally investigated as a function of dose with 60Co gamma rays. The calibration function obtained permits measurements of absorbed dose in the 2-50 Gy range, with a combined uncertainty of +/-4%. The lowest detectable dose was about 0.5 Gy. These properties are comparable with or even better than those of ESR dosimeters made from other materials. The time stability of the ESR signal of ammonium tartrate dosimeters at different storage conditions after irradiation was studied. A rather complex behaviour was observed, which suggests that more species of free radicals are produced by radiation and that migration processes may be effective. No dependence of the response on beam quality was found for high-energy photon and electron beams produced by a linear accelerator used in radiotherapy, whereas dose was underestimated with low-energy x-rays.

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Section: Dose Response and Background Signalmentioning

confidence: 77%

Response characterization of ammonium tartrate solid state pellets for ESR dosimetry with radiotherapeutic photon and electron beams

et al. 2001

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“…For ∆Rn, * change of "x/y ratio" at 2 nd operation cycle, ** change of "x/y ratio" by additive gamma rays irradiation to alanine dosimeters from NPP, *** estimated value from measured gamma dose and ∆RΓ, † calculated gamma dose using equation (4) generally, D2O moderated 252 Cf neutron source has been used as standard energy spectra to neutron rays for calibration of personal dosimeters in NPPs. However, from previous measurements by institutes, neutron flux and energy spectra in NPPs vary drastically with the measured positions and time.…”

Section: Resultsmentioning

confidence: 99%

“…Based on the aforementioned advantages as a long term dosimetry material, in the present study dozens of pellet type alanine dosimeters were installed at selected positions in a nuclear power plant (NPP) for two operation cycles. ESR dosimety is known as a retrospective dosimetry method that can be applied in an emergency after an accident and is accepted as a secondary standard and transfer dosimeter for the comparison of dose quantity between laboratories [3][4][5]. Recently, it was found that the peaks of spectra are mainly due to three kinds of radicals induced by radiation [6][7][8].…”

mentioning

confidence: 99%

Application of Alanine/Esr Spectrum Shape Change in Gamma Dosimetry

Choi¹,

Kim²,

Lee³

et al. 2010

Nuclear Engineering and Technology

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Temperature and radiation are two of the major environmental elements exerting aging effects on the incontainment instrumentation and control cables connected to major components. The effect of radiation on cable material is related to the total absorbed dose, which is mainly dependent on gamma rays [1]. For validity of radiation measurement, at least two operation cycles are required for the installation period. Generally used personal dosimeters are not appropriate for this application due to their rapid signal fading feature and relatively poor linearity at a range of high dose. Alanine-electron spin resonance (ESR) dosimetry material, meanwhile, has been proved to be suitable for long term measurement on the basis of the following factors: small signal dependency on temperature ( 0.2%/K), limited signal fading ( 1%/year), and low influence of humidity, which can be easily overcome by hermetic sealing of capsules [2]. Based on the aforementioned advantages as a long term dosimetry material, in the present study dozens of pellet type alanine dosimeters were installed at selected positions in a nuclear power plant (NPP) for two operation cycles. ESR dosimety is known as a retrospective dosimetry method that can be applied in an emergency after an accident and is accepted as a secondary standard and transfer dosimeter for the comparison of dose quantity between laboratories [3][4][5]. Recently, it was found that the peaks of spectra are mainly due to three kinds of radicals induced by radiation [6][7][8].The central resonance peak amplitude of main peaks is used to estimate radiation dose quantity. The weak "satellite line" beside the central resonance peak has been interpreted as the combined effects of "spin flip" of neighboring hydrogen protons of the methyl group of the paramagnetic center and a R2 radical [9][10][11]. The ratio of the "satellite line and main central resonance peak" is frequently expressed as the "x/y ratio". A decrease of this ratio has been explained by less saturation resistance of the main peak amplitude, which is caused by a decrease of the spin-lattice relaxation time T1. Crystallographic defects and plastic deformation in the structure of the alanine lattice by thermal shock of high linear energy transfer (LET) radiation have been reported as the most likely causes of relaxation time change. The "x/y ratio" irradiated with mixed radiation, composed of two radiations with different LET values, was reported to be intermediate and is determined by the absolute population size of each radical produced by radiation with different LET values. In this paper, the "x/y ratio" of alanine dosimeters returned from the containment building of the NPP is lower than that of dosimeters exposed to gamma rays. Furthermore, the ratio constantly decreased in proportion to the dose quantity, which corresponds with the installation period in the NPP. These results showed good accordance with previously reported results. Application of the above features to estimate gamma dose in mixed radiation fields is ...

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“…This would result in a valid protocol to estimate the inner pellet reproducibility. This aspect has never been included to validate a batch of pellets and may be added to those previously proposed (Dolo et al, 1996). This type of test may be used also to control the manufacturing process quality.…”

Section: Discussionmentioning

confidence: 99%