A.S. Sandhu

Annealing kinetics of heavy ion radiation damage in crystalline minerals

Abstract Studies have been made concerning the annealing behaviour of radiation damage due to heavy ion beams in some crystalline minerals, namely chlorite, biotite, phlogopite, apatite and zircon. Annealing experiments were carried out in the temperature range 200–950° C. The activation energy, E a , for track annealing is determined in the frame of a model involving a unique value of E a for a given detector.

Uranium estimation in water samples collected from some areas of Himachal Pradesh, India

Abstract Fission track technique has been used to estimate Uranium concentration in water samples belonging to some areas of Bilaspur, Mandi and Kulu districts of Himachal Pradesh, India. The samples are collected from springs and streams falling in river Bias. Uranium concentration has been found to vary from 0.07 to 4.65 ppb with a mean value of 0.72 ppb. Spring water samples from Gamrolla (Distt. Bilaspur) and Jashni (Distt. Kulu) have yielded comparatively higher Uranium values.

Etching and annealing kinetics of heavy ion tracks in quartz crystal

Abstract Swift heavy ions of sufficient size and energy produce stable latent tracks in most of the solid state nuclear track detectors. The etching and annealing kinetics of 208Pb (13.8 MeV/n) ion tracks in natural quartz crystal were investigated. The values of various etching parameters, viz. track etch rate VT, bulk etch rate VB, etching efficiency η and activation energy for track etching ET, are reported. The activation energy for annealing of latent tracks using a modified empirical formulation is determined.

Fission track annealing in minerals

Abstract Studies have been made concerning the annealing behaviour of nuclear tracks in some crystalline minerals, namely: quartz, zircon, chlorite and muscovite mica. Annealing experiments were carried out in the temperature range 300–1000°C. The activation energy, E a , for track annealing is determined in the flame of a model involving a unique value of E a for a given detector.

Anisotropic etching and annealing studies of fission tracks in zircon

Abstract The etching studies of fission tracks on various planes of zircon are carried out using two different sets of etchants: (a) 1:1 mixture of H2SO4: HF and (b) 4:15:6 mixture of NaOH:KOH:LiOH. H2O. It is observed that the track etching anisotropy is more in the basic medium (b) than in the acidic medium (a). The fossil tracks are etched more isotropically than induced tracks. The degree of anisotropy increases with the annealing of both fossil and induced tracks.

A study of track etch anisotropy in apatite

The track etch investigations on samples cut from different planes of apatite crystal are carried out in order to study the anisotropic etching behaviour of the crystal. The variation of the track etch characteristics with crystallographic orientations is observed. Because of track etch anisotropy in the crystal the fission track age determined on different planes of the crystal is found to vary. The etching conditions are standardised for different planes using HNO3 as the track etchant.

A global model for annealing in solid state track detectors

Abstract A systematic study of annealing phenomenon in solid state track detectors (SSTD) is presented using a quasi-equilibrium approach for the defects migration process. The nonlinear nature of the mechanism is also taken into account, which leads to an interesting formula for rate of annealing. Some of the experimentally tested empirical/semi-empirical formulae can also be deduced from it under certain approximations. The importance of the concept of relaxation time/hopping time is stressed. The temperature dependence of rate of annealing follows automatically from this formulation. Suggestion is made for experimental measurement of half life of fractional thermal fading of tracks so that the nonlinearity parameter can be computed and annealing process can be better understood.

Geochemical investigations for uranium in some areas of Himachal Pradesh using solid state nuclear track detectors

Abstract Fission track technique has been used to estimate uranium concentration in the samples of soil, rock and plants collected from some areas of Bilaspur, Mandi and Kulu districts of Himachal Pradesh, India. Uranium concentration in soil samples has been found to vary from 2.16 to 22.50 ppm., in rock samples from 1.41 to 10.34 ppm and in plants from 0.55 to 2.73 ppm. The anomalous uranium values have been obtained in soil, rock and plant samples from Thagan Nala region of Kulu district.

Thermal annealing of heavy ion tracks in muscovite mica

Abstract Thermal annealing of latent tracks caused by the passage of heavy ions, viz. Pb208 (13.8 MeV/n) and Ni58 (15.37 MeV/n), in muscovite mica is investigated. The activation energy for track annealing, determined using different annealing models, is compared. The effect of thermal annealing on size and energy resolution of heavy ions in mica, based on the track etch rate and track length reduction, is discussed.

Activation energy of track annealing in minerals as a function of interatomic spacing

Abstract Experiments have been performed to study the annealing of nuclear tracks in some crystalline minerals viz. apatite, zircon and garnet. It is observed that the value of activation energy of track annealing (Ea) depends upon the interatomic spacing. Some new results on activation energy of track annealing in crystalline minerals are reported.