Study of secondary cosmic rays using small stratospheric balloon missions

Study of Secondary Cosmic Rays and Astronomical X-Ray Sources using Small Stratospheric Balloons

“…In this paper, we present some important scientific results from our missions, such as the variation of secondary CRs as a function of altitude in the stratosphere, the detection of some astronomical X-ray sources using a unique methodology, and the analysis of the spectra of these sources. Notwithstanding severe limitations (details in Section 14), we achieved remarkable success (Chakrabarti et al 2017;Sarkar et al 2020;Sikdar et al 2023a). The intensity of primary CRs impinging on the top of the atmosphere depends on the geomagnetic field (Störmer 1956), geomagnetic storm (Dorman et al 1971), solar winds, etc., and the secondary CR is directly dependent on the primary CR.…”

“…The minimum photon counts due to CRs at about 1 km above the ground remain more or less the same for all the missions (as is evident on the left side in Figure 8), which we take as the normalization, and the normalization process with details is stated in Sarkar et al (2017). The peaks in Figure 8 represent the R-P maxima, where the leptonic and hadronic components of the cascade are the most intensive (Gaisser 1990), and they vary with solar activity and geomagnetic latitude (Ziegler 1996;Usoskin et al 2005;Sarkar et al 2017;Sikdar et al 2023a). In the atmosphere, the secondary cosmic radiation is a function of altitude (here, we take h in km) depending on the atmospheric density, and the ionization cross section is proportional to the square of h (Stozhkov et al 2002).…”

“…The details about the data quality and the extraction process were written and explained in Bhowmick et al (2019). Using our balloon data, we already showed the CRs to be anticorrelated with solar activity (Sarkar et al 2017;Sikdar et al 2023a) during solar cycle 24 and source detection method and timing properties of Crab pulsar (Sikdar et al 2023c), and we measured the spectrum of solar flares and a gamma-ray burst (Chakrabarti et al 2014;Sikdar et al 2023b). Details about data from the balloon missions are presented in Chakrabarti et al (2017).…”

“…Therefore, we have to model background radiation, which is based on our previous empirical model discussed . The background model present in Sarkar et al (2019) is used in the Sikdar et al (2023c) work and is also verified by the detailed calculations presented in Sarkar et al (2020) and Sikdar et al (2023a). We considered the detector background spectral range from altitude 20 to 30 km in each atmospheric layer of 1 km as normal backgrounds, as stated in Sarkar et al (2019).…”

“…In the detector background spectrum for mission D103, the energy lines are due to low background noise at ∼12 keV, due to natural radioactive sources 210 Pb at ∼42 keV, and 125 I at ∼68 keV, as clearly presented on the right side in Figure 10. The variation of low-energy background noise is varied exponentially, and other lines are Gaussian with energies for several atmospheric depths (Sarkar et al 2020;Sikdar et al 2023a).…”