Preliminary barometric and temperature coefficient measurements for secondary cosmic rays with DEASA experiment

Dayalbagh Educational Air Shower Array (DEASA) is the first detector array in Uttar Pradesh to investigate the physics of cosmic ray variations on various time scales, an important aspect in cosmic ray astronomy. The modulation of cosmic rays over longer time scales is related to solar activities, while shorter time variations can be associated with Earth’s atmospheric phenomena. In this paper, the atmospheric temperature and pressure measurements of DEASA detectors for 7 hours daily spanning 170 days are presented. These detectors have been calibrated since January 2022 and are located at Agra, India (27.18 • N, 78.02 • E, 170 m above sea level), with the geomagnetic rigidity cutoff value of 22 GV. The barometric coefficient obtained is −1.14 /mbar and the temperature coefficient is 0.4 • C −1 for the given period. The skewness and kurtosis for pressure distribution were −0.91 and −0.18, for temperature distribution were 0.40 and −1.05, and for count rates were −1.22 and 1.23. Further, linear regression analysis of the scatter plots between relative intensity vs. time, relative pressure vs. time, and relative temperature vs. time has been presented. The graphs between the relative intensity of cosmic ray flux and pressure and temperature respectively are shown, and the coefficients are compared with other experiments. The aim of our educational array is to carry out a physical understanding of the environmental parameters affecting the scintilla-tion detectors and make predictions. This is a prototype mini-array built at our institute with an electronic system for trigger selection, data storage, and online access.