Determination of Yield Functions of Neutron Counters at the South Pole from Monte-Carlo Simulation
Issued Date
2022-03-18
Resource Type
eISSN
18248039
Scopus ID
2-s2.0-85144106571
Journal Title
Proceedings of Science
Volume
395
Rights Holder(s)
SCOPUS
Bibliographic Citation
Proceedings of Science Vol.395 (2022)
Suggested Citation
Pagwhan A. Determination of Yield Functions of Neutron Counters at the South Pole from Monte-Carlo Simulation. Proceedings of Science Vol.395 (2022). Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/86580
Title
Determination of Yield Functions of Neutron Counters at the South Pole from Monte-Carlo Simulation
Author(s)
Other Contributor(s)
Abstract
Neutron monitors (NM64) are ground-based cosmic ray detectors that measure the flux of primary cosmic rays at the GeV-energy range by counting (primarily) secondary neutrons in atmospheric cascades. They have a lead producer to generate evaporation neutrons that are moderated before being detected in a 10BF3 or 3He gas-filled proportional counter. By omitting the lead, a so-called “bare detector” responds to lower energy particles on average and can be used in coincidence with NM64 detectors to estimate the primary cosmic rays’ energy spectrum. This research uses the FLUKA Monte Carlo simulation package to refine our understanding of two types of bare neutron detector and three NM64 units located inside and outside, respectively, of the Amundsen-Scott station at the South Pole. One bare design uses paraffin and wood to moderate high-energy neutrons, and another bare design has no moderator. All bares are mounted together in a single assembly. The bares and NM64 all use 3He gas-filled proportional counters. In our previous work, the energy-dependent effective area (yield function) of the paraffin-moderated bares was directly determined from a ship-borne latitude survey in 2009 - 2010. The influence of the container and the environment on the ship significantly affects the measured yield function. In this work, we use simulations to relate the measured yield functions to the actual configuration at the South Pole to study spectral variations of solar energetic particles during Ground Level Enhancements.