Manwinder Singh

Calibration of radon detectors

Abstract The detectors used for the radon estimation are calibrated in order to express the radon concentration from tracks/mm2 hr and counts/min in terms of absolute activity in pCi/ml. The distribution characteristics of radon gas in a liquid-gaseous interphase are made use of in the calibration.

Subsurface soil gas radon changes associated with earthquakes

Abstract Radon concentration within the ground but close to the surface are being measured continuously from 1984 for earthquake prediction. During this period several radon anomalies considerably larger than meteorologically induced variations are recorded. These anomalies are followed by an earthquake of magnitude above 3.8 occured within 3 to 10 days, at an epicentral distance 100 to 400 km.

Uranium and radon estimation in water and plants using SSNTD

Abstract Lexan plastic track detector is used to estimate the uranium content of water and plant samples collected from the Dalhousie area, Chamba district, Himachal Pradesh, India. Uranium content has been found to vary from 0.26 ± 0.01 to 6.77 ± 0.06 ppb in water and from 0.65 ± 0.04 to 2.61 ± 0.08 ppm in plant samples. The track production rate due to radon in water has been found to vary from 1.44 ± 0.18 to 385.25 ± 0.70 tracks cm -2 hr -1 litre -1 using LR-115 plastic as a solid state nuclear track detector.

Radon survey for uranium prospection using alpha detectors

Abstract The results of radon survey for uranium prospection using alpha track detector and radon emanometer in some geological area are reported. The Rn-Tn discriminator with plastic track detectors in which air column acts as diffusion barrier is employed for separating Rn from Th.

Uranium and thorium analysis in geological samples using plastic track detectors

Abstract The relation given by Coppens (1977) between the concentrations of Uranium (U) and Thorium (Th) in geological samples and corresponding alpha track rate employing nuclear emulsions is: 10 6 N = (9.20U + 2.80Th) k The modified formula for use in LR-115 type 2 plastic track detector is proposed as under: 10 6 N = (6.77U + 1.60Th) k Uranium is estimated using fission track technique and Th is calculated by alpha autoradiography. The absorption coefficient (k) is determined from the composition of the sample under study. The proposed formula is applied for Th analysis in phosphorite samples from Mussourie Syncline, U.P. (India). Gamma ray spectrometric analysis of phosphorite samples establish the validity of the modified relation for U and Th estimation. The quartizite samples collected from Kulu area of Himachal Pradesh (India) are analysed using modified relation. The value of absorption coefficient k is found to be 14.29 for quartzite rock. U and Th contents are found to vary from 2.63 to 18.73 ppm and 0.92 to 95.92 ppm, respectively.

Etching studies of fission damage in quartz

Abstract Etching characteristics of fission fragment tracks in quartz have been studied using NaOH as the track etchant. The track etching efficiency of 87.9% has been observed corresponding to the etching temperature of 150°C. The activation energies for bulk and track etching have been found to be 0.43 eV and 0.22 eV respectively.

A fission track technique used for biogeochemical prospecting in Northern India

A fission track technique was employed to determine the uranium (U) content of plant species collected from different locations of the middle and outer Himalayas. The regional threshold for U content was 5.5 μg/g for plants of this area. Berberis brachybotrys and Adhatoda vesica were suitable for biogeochemical prospecting. The identification of anomalies in an area of U mineralization, confirmed that the biogeochemical technique could be successfully used in the exploration for uranium.

Radon-Thoron estimation using LR-115 plastic track detector

Abstract LR-115 plastic track detector and a Radon-Thoron discriminator has been used to estimate the radon (Rn) and thoron (Tn) contents in the soil of Guru Nanak Dev University Campus area. Track production rates in the soil at different depths have been studied. Uranium estimation in the soil samples from the experimental site have also been made to establish some correlation with Rn emission. Rn-emanation rates from the plants growing around the experimental site have also been studied using LR-115 plastic track detector. Plant leaves have been found to emanate more Rn than stems.

Uranium estimation in Siwalik vertebrate fossil bones using SSTD

Abstract Results of fission track analysis for uranium content in Siwalik vertebrate fossil bones are reported. Background threshold for U content in fossil bones of this area is found to be 56.23 ppm. Uranium anomalies of 159.77, 165.10 and 418.08 ppm, respectively are found in samples from Saharanpur (U.P.), Naraingarh (Haryana) and Nalagarh (H.P.) areas of Siwalik Himalayas. The alpha-autoradiographic studies yield a linear relationship between alpha track rate and uranium content in the samples. The calibration curve obtained can be used to estimate the unknown U content in the Siwalik fossil bones. Uranium distribution studies on molar teeth of stagdon show U enrichment in ferruginous matrix in comparison to siliceous matrix.

Laboratory studies on the behaviour of radon diffusion through soil

The diffusion of radon through the soil has been studied by measuring the radon build-up with time at varying thicknesses and and porosities of the soil. Radon diffusion is found to be dependent on the porosity and thickness of the soil column.