Farshid Pourranjbar; Elham Edalatkhah; Seyed Mohammad Mahdi Abtahi
Abstract
Fricke gel dosimeters obtained by modifications on standard Fricke dosimeter presents some advantages like easy preparation, tissue equivalence, good reproducibility and dose mapping. In this work, dose response characteristics of Gelatin Fricke gel dosimeters ...
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Fricke gel dosimeters obtained by modifications on standard Fricke dosimeter presents some advantages like easy preparation, tissue equivalence, good reproducibility and dose mapping. In this work, dose response characteristics of Gelatin Fricke gel dosimeters was investigated and compared with Fricke agarose gel dosimeters in terms of sesitivity. After prepration of three different formulation of Gelatin Fricke gel dosimeters and gamma irradiation of the samples, a spectrophotometer was applied to measure the optical absorbance of the samples. Results indicate a linear dose range response of 10 to 30 Gy, as well as increased gelatin concentrations cause the sensitivity of the dosimeter to detereorate with a 80% reduction of dose response for a change in gelatin concentration from 3 to 8 weight percent. Obtained coefficient variation verifies the good repeatability of the gel response. The gel dosimeter has no dose rate dependence. Comparison of the most sensitive Gelatin Fricke gel sample with the prepared Fricke agarose gel samples confirm that Fricke agarose dosimeter is more sensitive than Gelatin Fricke gel dosimeter.
Elham Edalatkhah; Mahsa Sedighi; Payvand Taherparvar
Abstract
Gamma radiation indicators are appropriate tools for monitoring visually whether or not the irradiation process has been carried out properly. Among chemical radiation indicators available worldwide, a few are suitable for monitoring low dose ranges (especially for blood irradiation, below 50 Gy). Addressing ...
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Gamma radiation indicators are appropriate tools for monitoring visually whether or not the irradiation process has been carried out properly. Among chemical radiation indicators available worldwide, a few are suitable for monitoring low dose ranges (especially for blood irradiation, below 50 Gy). Addressing this scope, PVA-Fricke gel was proposed in this work. Irradiation of the prepared PVA-Fricke gel samples was performed by Co-60 gamma cell unit up to a dose of 80 Gy. Color change of the samples was observed from orange to purple proportional to increasing absorbed dose. Prepared samples were divided into three groups, kept at different environmental conditions, to investigate stability of the gel against temperature and light. Results revealed that the irradiated samples kept at dark and refrigerator were stable for seven days. Optical absorbance measurement of the samples also estimated pre- and post-irradiation color stability. The gel can be easily used to identify processed and unprocessed products in blood irradiation. Although the gel is designed to be a qualitative indicator, it is also a good quantitative dosimeter for gamma rays.
Elham Edalatkhah; Shahab Sheibani
Abstract
By expanding the applications of GEM detectors, a newer pattern of such detectors was introduced in 2004, named THGEM detectors. In this work, a sample of an X-ray detector was designed and constructed using 2cm×2cm THGEMs domestically produced with a thickness of 250 μm, a hole diameter of ...
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By expanding the applications of GEM detectors, a newer pattern of such detectors was introduced in 2004, named THGEM detectors. In this work, a sample of an X-ray detector was designed and constructed using 2cm×2cm THGEMs domestically produced with a thickness of 250 μm, a hole diameter of 300 μm and a pitch of 500 μm, for the first time. The triple THGEM detector working in Ar/CO2 gas mixture was characterized. Influence of gas pressure and gas mixture on gain of the detector was investigated. Results show the detector operated in a stable mode with no discharges. The gain of the detector increased with high voltage across the THGEM electrodes exponentially. This verified the performance of a detector as a proportional counter. Also, the detector’s gain is maximum at Ar/CO2 (80/20) gas mixture and voltage of 700 V applied to each multiplier. The detector is promising for localization applications such as particle physics experiments.
