Surrounding material effect on measurement of thunderstorm-related neutrons

Abstract

Observations of strong flux of low-energy neutrons were made by ${}^3\mathrm{He}$ counters during thunderstorms [Gurevich et al (Phys. Rev. Lett. 108, 125001, 2012)]. How the unprecedented enhancements were produced remains elusive. To better elucidate the mechanism, a simulation study of surrounding material impacts on measurement by ${}^3\mathrm{He}$ counters was performed with GEANT4. It was found that unlike previously thought, a ${}^3\mathrm{He}$ counter had a small sensitivity to high-energy gamma rays because of inelastic interaction with its cathode-tube materials (Al or stainless steel). A ${}^3\mathrm{He}$ counter with the intrinsic small sensitivity, if surrounded by thick materials, would largely detect thunderstorm-related gamma rays rather than those neutrons produced via photonuclear reaction in the atmosphere. On the other hand, the counter, if surrounded by thin materials and located away from a gamma-ray source, would observe neutron signals with little gamma-ray contamination. Compared with the Gurevich measurement, the present work allows us to deduce that the enhancements are attributable to gamma rays, if their observatory was very close to or inside a gamma-ray emitting region in thunderclouds.

arXiv commentAccepted for publication in Astroparticle Physics.29 Pages, 9 figures

References in corpus (5)

• Detection of high-energy gamma rays from winter thunderclouds
• Observation of thundercloud-related gamma rays and neutrons in Tibet
• Observation of an energetic radiation burst from mountain-top thunderclouds
• Hardening and termination of long-duration gamma rays detected prior to lightning
• Observation of neutron bursts produced by laboratory high-voltage atmospheric discharge

Cited by in corpus (1)

• The prolonged gamma ray enhancement and the short radiation burst events observed in thunderstorms at Tien Shan