The use of mercury as a supplementary inner shielding material for low-background gamma-ray spectrometry

Abstract

Gamma-ray spectroscopic measurements of low-level environmental samples require the reduction of the background as low as practicable. In the present work, we investigate the advantages of adding Hg passive shielding inside a low-background Pb-shield to further reduce the background radiation. The background count rate achieved by the Pb-shield alone over the energy interval from 25 to 2700 keV, amounts to 8.4 × 10 −4 counts/s.keV which is ∼ 1.5% of the normal background. The introduction of Hg-shield adds another 15% reduction. On the average, the Hg-shield suppresses the net peak areas of X-and gamma-rays to < 3 and 1% of the normal background, respectively. On the other hand, the reduction in the count rate of these peaks due to the addition of Hg-shield varies according to the energy. The measurements showed no evidence of the presence of cosmogenically produced 194 Hg in the measured spectra. An additional 2% reduction was achieved by using neutron moderators.

Multivariate Statistical Analysis of High Background Radiation Area on the Hadhramout Coast

“…In order to minimize the background radiation, the detector and the sample were housed in a cylindrical low-background Pb shield with 10 cm thickness (Canberra 747E). This shield was found to reduce the background in the gamma-ray spectra from 25 to 2700 keV by an attenuation factor of 98.5 % [21]. The whole experimental setup (detector and shields) was surrounded from the four sides with 2.5-cm borax and 3.5-cm paraffin wax.…”

Multilayer magnetic shielding for testing a superconducting single-flux-quantum circuit chip in liquid helium dewar

“…Devore [4] utilized a light weight and high permeability material to form a truncated cone around a photomultiplier tube and improved its collection efficiency. Al-Sharkawy [8] added a Hg passive shielding inside a Pb-shield for the low-level gamma-ray spectrometers. Ren [9] found that the double-layer magnetic shield was theoretically as two times as that of the single-layer magnetic shield.…”