Current Science

D. K. Panda ¹, D. Banerjee ¹, S. K. Goyal ¹, A. R. Patel ¹, A. D. Shukla ¹

Affiliations
1 Planetary Sciences and Exploration Group, Physical Research Laboratory, Ahmedabad 380 009, IN

Abstract

We present the development of a cerium-doped lanthanum bromide (LaBr₃ : Ce) gamma-ray spectrometer (GRS) with the primary objective of determining the abundance and distribution of Th, U, K, and other major elements, including Fe on the entire planetary surface by measuring gamma-ray signals produced by radioactive decay, neutron inelastic scattering and neutron capture reactions in the energy region 0.03- 8 MeV. The energy resolution of the LaBr3 : Ce GRS developed in-house using front-end and processing electronics at 511 and 1274 keV is estimated to be 4.1% and 2.5% respectively. The intrinsic activity count rate for our 3ⁿ * 3ⁿ LaBr₃ : Ce GRS is ~61 counts s^-1 (i.e. ~0.18 counts s^-1 cm^-3) for the 40K energy window (1400-1520 keV) and ~3.4 counts s^-1 for the ²³²Th (2550-2700 keV) energy window. Although this large intrinsic activity of the LaBr₃ : Ce crystal inhibits estimation of the concentrations of Th and K, our attempts using a NaI(Tl) GRS (with electronics developed in-house) were more successful. The Th concentration of US-110 was estimated to be ~11.4 ppm and is within 14% of the 13.2 ppm value determined using a HPGe GRS. The K concentration of US-110 was estimated to be 0.87% and is within ~10% of the 0.78% value determined independently using a HPGe GRS.

Keywords

Cerium Radioactive Elements, Gamma Ray Spectroscopy, Lanthanum Bromide, Sodium Iodide.

Full Text

   

Shalini Dhyani ¹, S. K. Goyal ¹

Affiliations
1 EIRA Division, CSIR-National Environmental Engineering Research Institute, Nehru Marg, Nagpur 440 020, IN

Abstract

The extensive damage to natural ecosystems at large due to climate-led variability and vulnerability poses a serious threat to human life. Environmental sustainability is a criterion for economic progress and poverty bargain in Asia. Climate change accelerated by human-induced pressures is threatening the development and security of Asia. The poor are particularly vulnerable to these changes and are already suffering from rising sea levels and increasingly devastating storms, droughts and floods. Urgent action is needed to integrate both extenuation of greenhouse gas emissions and climate change adaptation measures into the development strategy of the region.

Full Text