Low energy secondary cosmic ray flux (gamma rays) monitoring and its constrains

TL;DR

This study monitored low energy secondary cosmic ray flux variations during lunar phases, revealing sudden enhancements linked to atmospheric radioactivity, and providing constraints on SCR flux measurement methods during eclipses.

Contribution

It presents the first detailed measurement of low energy SCR flux variations during lunar phases, identifying atmospheric Ar-41 as a source of gamma ray enhancements.

Findings

Observed 200% flux enhancement during specific events.

Detected atmospheric Ar-41 as a gamma ray source.

Provided constraints on low energy SCR flux monitoring.

Abstract

Temporal variation of secondary cosmic rays (SCR) flux was measured during the several full and new moon and days close to them at Department of Physics, University of Mumbai, Mumbai (Geomagnetic latitude: 10.6 N), India. The measurements were done by using NaI (Tl) scintillation detector with energy threshold of 200 keV. The SCR flux shows sudden enhancement for approximately about 2 hour in counts during couple of events out of all experimental observations. The maximum Enhancement SCR flux is about 200% as compared to the diurnal trend of SCR temporal variations. Weather parameters (temperature and relative humidity) were continuously monitored during all observation. The influences of geomagnetic field, interplanetary parameters and tidal effect on SCR flux have been considered. Summed spectra corresponding to enhancement duration indicates appearance of atmospheric radioactivity which shows single gamma ray line. Detail investigation revealed the presence of radioactive Ar 41 . This measurements puts limitations on low energy SCR flux monitoring. This paper will help many researcher who want to measure SCR flux during eclipses and motivate to find unknown mechanism behind decrease/ increase during solar/lunar eclipse.