[show abstract][hide abstract] ABSTRACT: In the present work, attempts have been made to investigate the modification in particle track etching response of polyallyl
diglycol carbonate (PADC) due to impact of 2 MeV electrons. PADC samples pre-irradiated to 1, 10, 20, 40, 60, 80 and 100 Mrad
doses of 2 MeV electrons were further exposed to 140 MeV28 Si beam and dose-dependent track registration properties of PADC have been studied. Etch-rate values of the PADC irradiated
to 100 Mrad dose electron was found to increase by nearly 4 times that of pristine PADC. The electron irradiation has promoted
chain scissioning in PADC, thereby converting the polymer into an easily etchable polymer. Moreover, the etching response
and the detection efficiency were found to improve by electron irradiation. Scanning electron microscopy of etched samples
further revealed the surface damage in these irradiated PADCs.
[show abstract][hide abstract] ABSTRACT: It is a common practice since long to follow the ion track-etching process in thin foils via conductometry, i.e . by measurement of the electrical current which passes through the etched track, once the track breakthrough condition has been achieved. The major disadvantage of this approach, namely the absence of any major detectable signal before breakthrough, can be avoided by examining the track-etching process capacitively. This method allows one to define precisely not only the breakthrough point before it is reached, but also the length of any non-transient track. Combining both capacitive and conductive etching allows one to control the etching process perfectly. Examples and possible applications are given.
Radiation Effects and Defects in Solids - RADIAT EFF DEFECT SOLID. 01/2006; 161(3):161-175.
[show abstract][hide abstract] ABSTRACT: It has been well recognised all over the world that inhalation of indoor radon (222Rn), thoron (220Rn) and their daughter products contribute a major fraction of total dose to human beings from all possible sources of natural radioactivity. North-eastern region being in a zone of high seismicity, the indoor radon and thoron map of the region will provide a valuable database for any study related to radon and thoron anomalies. Radon enters living area mainly through floor from subsoil and building materials, and starts accumulating in poorly ventilated dwellings. So, concentration of radon and its progeny are usually higher in indoor air than in outdoor air. In the present work, an attempt has been made to assess the levels of radon, thoron and their progeny in dwellings of a few cities in the north-eastern region of India using a passive time integrated monitoring with the help of twin chamber dosimeters having LR-115 as the detector.
[show abstract][hide abstract] ABSTRACT: It is a well-known fact that proton irradiation leads to an increase in track registration sensitivity of some polymers. In the present work, the effect of the proton beam irradiation through metal foils (gold and aluminium) on polyallyldiglycol carbonate (PADC) has been studied by track technique. An increase in sensitivity of PADC adjacent to the gold foils has been found which is attributed to the effect of ionisation by the secondary particles emitted from the metal targets due to proton bombardment.
[show abstract][hide abstract] ABSTRACT: Heavy ion induced modification in optical absorption studies of the polymers Polypropylene and Polyimide have been carried out to investigate the potential for improvements in their conductivity properties. The polymers were irradiated to four different doses of 140 MeV 28Si and 100 MeV 58Ni ion beams. The optical absorption studies were carried out by UV-Vis spectroscopy. The shift in the absorption edges were correlated to the optical band-gap by Tauc's expression. A decrease in optical band-gap has been observed in the irradiated polymers, but the effect of 58Ni ions were more pronounced in decreasing the band-gap in the polymers.
Radiation Effects and Defects in Solids 01/2001; 153(4):335-341. · 0.50 Impact Factor
[show abstract][hide abstract] ABSTRACT: Ranges and energy-loss up to 4.7 MeV/u 28Si ions in Makrofol-G polymer have been determined using a nuclear track technique. Polyallyldiglycol carbonate (CR-39) detectors were calibrated using Al degraders to determine the degraded energy of 28Si ions after passing through the different stacks of Makrofol-G placed in the staircase configuration. The mean ranges of 28Si in Makrofol-G have also been determined at different energies between 1.0 MeV/u and 4.7 MeV/u. The experimental results are discussed and compared with the theoretical values obtained from four different computer codes.
Radiation Effects and Defects in Solids 04/1999; 147(4):273-281. · 0.50 Impact Factor
[show abstract][hide abstract] ABSTRACT: The effect of Gamma radiation in Polyallydiglycol carbonate (PADC) detectorrs has been studied in the dose range of 100–106 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 60Co Source in PADC. The experimental results are presented and discussed.
[show abstract][hide abstract] ABSTRACT: The mean ranges and energy-loss of different energies of 161Dy in Hostaphan and Kapton have been determined using the nuclear track technique. Calibrated detectors of PADC are used for 161Dy 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 161Dy 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.
[show abstract][hide abstract] ABSTRACT: Potential alpha energy concentration (PAEC) due to radon and its progenies has been measured in dwellings of three different cities in India; namely Allahabad (in north central region), Vishakapatnam (in south eastern region) and Shillong (in north eastern region), The measurements were carried out by a passive, time-integrated method, using LR 115 (Type II) detector in bare mode. The geometric mean of potential alpha energy concentration in dwellings of Allahabad, Vishakapatnam and Shillong has been estimated to 10.0 mWL, 3.9 mWL and 11.3 mWL, respectively. The results obtained for dwellings in these three cities are discussed in the light of exposure limits set by the International Commission on Radiological Protection (ICRP).
[show abstract][hide abstract] ABSTRACT: The mean ranges and energy-loss of different energies of 86Kr and 197Au in tantalum have been determined by using the nuclear track technique. Calibrated detectors of CR-39 are used for measuring energies of the transmitted krypton and gold ions from tantalum foils of different thickness. The experimental values of mean ranges and energy-loss of 86Kr up to 17.7 MeV/A and of 197Au up to 13.5 MeV/A have been obtained in tantalum. These values are compared with theoretical ranges derived from four different prescriptions.
[show abstract][hide abstract] ABSTRACT: The experimental results on the characterization of three polymeric solids in terms of energy-loss of 20–80 MeV 12C ions in Kapton, Hostaphan and Makrofol-N have been presented and compared with theoretical values.