ABSTRACT
Commercial glasses have been investigated for their application in accidental gamma dose measurement using Thermoluminescent (TL) techniques. Some of the glasses have been found to be sensitive enough that they can be used as TL dating material in radiological accident situation for gamma dosimetry with lower detection limit 1 Gy (the dose significant for the onset of deterministic biological effects). The glasses behave linearly in the dose range 1-25 Gy with measurement uncertainty +/- 10%. The errors in accidental dose measurements using TL technique are estimated to be within +/- 25%. These glasses have shown TL fading in the range of 10-20% in 24 h after irradiation under room conditions; thereafter the fading becomes slower and reaches upto 50% in 15 d. TL fading of gamma-irradiated glasses follows exponential decay pattern, therefore dosimetry even after years is possible. These types of glasses can also be used as lethal dose indicator (3-4 Gy) using TL techniques, which can give valuable inputs to the medical professional for better management of radiation victims. The glasses are easy to use and do not require lengthy sample preparation before reading as in case of other building materials. TL measurement on glasses may give immediate estimation of the doses, which can help in medical triage of the radiation-exposed public.
Subject(s)
Gamma Rays , Radiometry/methods , Thermoluminescent Dosimetry/instrumentation , Calibration , Dose-Response Relationship, Radiation , Glass , Powders , Radiation Dosage , Radiometry/instrumentation , Reproducibility of Results , Temperature , Thermoluminescent Dosimetry/methods , Time Factors , Trace Elements/analysisABSTRACT
Commercial glasses under this study showed linear thermoluminescence (TL) response in gamma dose range 100 Gy to 10 kGy, glow peaks between 175 and 200 degrees C, fading under dark and room light 2.86-7.36% and 10.42-20.82%, respectively, in 24h and 34.86-70.80% under sunlight in 5h after exposure. The TL glass dosimetric results have been found to be reproducible within +/- 6.0%. Glasses have been observed as thermally unstable and its TL sensitivity reduces after annealing. The TL response of the glasses has been found to reduce by 7.40-51.49% after first annealing of the samples at 400 degrees C for 15 min. The trace element study suggests that presence of impurities has no role in TL sensitivity of glasses rather imperfections and dislocations in the lattice are the major contributor in the formation of TL centers. Commercial glasses can serve as good TL material for gamma irradiator and gamma chamber dosimetry. The various radiation parameters for glass TL dosimetry have been studied in detail and presented.
ABSTRACT
Post-irradiation identification and dose estimation are required to assess the radiation-induced effects on living things in any nuclear emergency. In this study, radiation-induced morphological/cytological changes i.e., number of root formation and its length, shooting length, reduction in mitotic index, micronuclei formation and chromosomal aberrations in the root tip cells of gamma-irradiated onions at lower doses (50-2000 cGy) are reported. The capabilities of this biological species to store the radiation-induced information are also studied.
