Measuring Contributions from Single and Multiple Atmospheric Secondary Cosmic Rays in the Princess Sirindhorn Neutron Monitor Using Cross-counter Neutron Time Delay Distributions
3
Issued Date
2026-06-10
Resource Type
ISSN
0004637X
eISSN
15384357
Scopus ID
2-s2.0-105041047823
Journal Title
Astrophysical Journal
Volume
1004
Issue
1
Rights Holder(s)
SCOPUS
Bibliographic Citation
Astrophysical Journal Vol.1004 No.1 (2026)
Suggested Citation
Mitthumsiri W., Sáiz A., Ruffolo D., Evenson P., Mangeard P.S., Nuntiyakul W., Banglieng C. Measuring Contributions from Single and Multiple Atmospheric Secondary Cosmic Rays in the Princess Sirindhorn Neutron Monitor Using Cross-counter Neutron Time Delay Distributions. Astrophysical Journal Vol.1004 No.1 (2026). doi:10.3847/1538-4357/ae6efa Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/117260
Title
Measuring Contributions from Single and Multiple Atmospheric Secondary Cosmic Rays in the Princess Sirindhorn Neutron Monitor Using Cross-counter Neutron Time Delay Distributions
Corresponding Author(s)
Other Contributor(s)
Abstract
Neutron monitors (NMs) are ground-based devices designed to measure cosmic-ray count rates by monitoring atmospheric neutrons from cosmic-ray showers. We present results from new electronics that have recorded cross-counter time delay histograms for the Princess Sirindhorn Neutron Monitor (PSNM) at the summit of Doi Inthanon, Thailand. From these histograms, we have extracted the cross-counter leader fraction (L) and corrected it for atmospheric effects. For large counter separation, we measure nearly constant L ≈ 0.997, implying that 0.3% of counts in one counter are temporally associated with later counts on a given distant counter. Monte Carlo simulations confirm that individual secondary particles cannot account for the associated counts at large counter separation, which instead requires a contribution from multiple secondary particles in the same cosmic-ray shower that is apparently independent of distance over 3 to 7.5 m. We infer that ≈4.5% of PSNM counts are associated with a later count in at least one of its 18 counters from a different secondary particle in the same shower. Monte Carlo simulations of atmospheric showers and NM yield functions can be validated using our measurements of neutron multiplicity across counters and the contributions of single and multiple secondary particles. These measurements also improve understanding of the single-counter L, which has been used for precise tracking of cosmic-ray spectral variations and extending the range of NM observations to higher energies.