D. Sinha

Gamma ray photon-induced modifications in Triafol-TN and Triafol-BN polymeric track detectors

Abstract Photon induced modifications in Triafol-TN and Triafol-BN polymers have been studied in the dose range of 10 1 –10 6 Gy at room temperature using a 60 Co source. To monitor the chemical and structural changes induced by gamma rays, UV, IR, and ESR studies were carried out. Thermal studies were also conducted for understanding the effects of gamma irradiations on these polymers. Variation of track etching characteristics and activation energy for bulk etching have been studied at different gamma rays doses. The experimental results are presented and discussed.

Effect of gamma rays on PADC detectors

Abstract The effect of Gamma radiation in Polyallydiglycol carbonate (PADC) detectorrs has been studied in the dose range of 10 0 –10 6 Gy. Some of the properties like bulk-etch rate, track-etch rate, activation energy for bulk and track-etching have been found out for different gamma doses from 60 Co Source in PADC. The experimental results are presented and discussed.

Measurement of potential alpha energy exposure (PAEE) of radon and its progenies in dwellings in the North-Eastern region of India

Abstract The potential alpha energy exposure (PAEE) due to radon and its progenies has been measured in dwellings at five different locations in the north-eastern region of India. The measurements were carried out using the passive time-integrated method by employing LR-115 (Type II) solid state nuclear track detector (SSNTD). The data obtained in the present work has been compared with the indoor radon levels prescribed by the international Commission on Radiological Protection (ICRP) at which intervention may be considered. The geometric mean of potential alpha energy exposure (PAEE) due to indoor radon in dwellings of 24 towns in India is estimated as 8.8 ± 3.6 mWL and the corresponding annual effective dose equivalent (AEDE) values has been found to be 2.7 ± 1.1 mSv y−1. A national average of indoor radon level was found to be 81 Bq m−3. The results are compared with the corresponding data of a few selected countries.

Gamma-photon induced modifications in Polyvinylchloride (PVC) film

Gamma photon induced modifications in Polyvinylchloride (PVC) polymer have been studied in the dose range of 101-106Gy at room temperature. Polyvinylchloride films have been irradiated with different doses of gamma radiation from a 60Co source. To monitor the chemical and structural changes caused by gamma radiation IR and UV-Vis spectroscopy of pristine and irradiated PVC have been performed and using the spectral data some changes in the properties have been investigated. The spectral studies have indicated that at a dose of 106Gy scissioning of the C-a bonds takes place. This scissioning of the chain initiates decomposition at a lower temperature. Thermal stability of the polymer reduces due to irradiation but the decomposition patterns remain the same. The optical band-gap is found to decrease due to irradiation at doses bigher than 103Gy.

Structural modifications and track registration response of some gamma irradiated polycarbonate detectors

Abstract Makrofol-E, Lexan and Polycarbonate detectors exposed to gamma irradiation in the dose range of 101-106 Gy have been characterized by track methods and UV-Vis, IR and ESR spectroscopy. The track registration response is studied through variation of etching characteristics and the activation energy for bulk-etching at different doses of gamma rays was determined. Thermal stability studies were also carried out for understanding the effects of gamma irradiation on the thermal resistance of these irradiated polymers. The experimental results show that up to 106 Gy gamma exposure the examined materials are rather gamma insensitive radiation hard detectors.

Mean ranges of 161Dy in Hostaphan and Kapton and maximum etchable track lengths in ZnP-glass detector

Abstract The mean ranges and energy-loss of different energies of 161 Dy in Hostaphan and Kapton have been determined using the nuclear track technique. Calibrated detectors of PADC are used for 161 Dy ions through targets of different thickness. The experimental mean ranges are compared with theoretical values derived from three different prescriptions. In another experiment the track lengths of 161 Dy ions at five different energies were measured in Zn-P glass and the experimental track lengths have been compared with theoretical values obtained from three different computer codes.

Energy-loss of 20-80 MeV 12C ions in polymeric solids

Abstract The experimental results on the characterization of three polymeric solids in terms of energy-loss of 20–80 MeV 12 C ions in Kapton, Hostaphan and Makrofol-N have been presented and compared with theoretical values.