Moisture effect in prompt gamma measurements from soil samples

A A Naqvi; F Z Khiari; F A Liadi; Khateeb-Ur-Rehman; M A Raashid; A H Isab

doi:10.1016/j.apradiso.2016.06.010

Moisture effect in prompt gamma measurements from soil samples

Appl Radiat Isot. 2016 Sep:115:61-66. doi: 10.1016/j.apradiso.2016.06.010. Epub 2016 Jun 14.

Authors

A A Naqvi¹, F Z Khiari², F A Liadi², Khateeb-Ur-Rehman², M A Raashid², A H Isab³

Affiliations

¹ Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia. Electronic address: aanaqvi@kfupm.edu.sa.
² Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia.
³ Department of Chemistry, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia.

PMID: 27337651
DOI: 10.1016/j.apradiso.2016.06.010

Abstract

The variation in intensity of 1.78MeV silicon, 6.13MeV oxygen, and 2.22MeV hydrogen prompt gamma rays from soil samples due to the addition of 5.1, 7.4, 9.7, 11.9 and 14.0wt% water was studied for 14MeV incident neutron beams utilizing a LaBr3:Ce gamma ray detector. The intensities of 1.78MeV and 6.13MeV gamma rays from silicon and oxygen, respectively, decreased with increasing sample moisture. The intensity of 2.22MeV hydrogen gamma rays increases with moisture. The decrease in intensity of silicon and oxygen gamma rays with moisture concentration indicates a loss of 14MeV neutron flux, while the increase in intensity of 2.22MeV gamma rays with moisture indicates an increase in thermal neutron flux due to increasing concentration of moisture. The experimental intensities of silicon, oxygen and hydrogen prompt gamma rays, measured as a function of moisture concentration in the soil samples, are in good agreement with the theoretical results obtained through Monte Carlo calculations.

Keywords: 14MeV neutron based PGNAA setup with LaBr(3):Ce detector; Decreasing intensity of Si gamma ray with moisture; Hydrogen and oxygen gamma ray intensity measurements; Increasing intensity of hydrogen with moisture; Monte Carlo calculation for gamma ray intensity from soil samples; Silicon; Soil samples with 0–14wt% moisture concentration.