Determination of Yield Functions of Neutron Counters at the South Pole from Monte-Carlo Simulation

Discussion timeslot (ZOOM-Meeting): 16. July 2021 - 18:00
ZOOM-Meeting URL: https://icrc2021.desy.de/pf_access_abstracts
Corresponding Session: https://icrc2021-venue.desy.de/channel/Presenter-Forum-1-Evening-All-Categories/48
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 atmosphere cascades. They have a lead producer to generate evaporation neutrons that are moderated before being detected in a boron-trifluoride or helium-3 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 concurrence within NM64 to estimate the primary cosmic rays' energy spectrum. This research uses Monte-Carlo FLUKA simulation 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 and apply our results to study spectral variations of solar energetic particles during Ground Level Enhancements."

Authors: Audcharaporn Pagwhan
Co-Authors: Waraporn Nuntiyakul | Achara Seripienlert | Paul Evenson | Pierre-Simon Mangeard | Alejandro Sáiz | David Ruffolo | Surujhdeo Seunarine 
Indico-ID: 338
Proceeding URL: https://pos.sissa.it/395/1246