University of Oulu

Similä, M., Usoskin, I., Poluianov, S., Mishev, A., Kovaltsov, G. A., & Strauss, D. T. (2021). High-altitude polar NM with the new DAQ system as a tool to study details of the cosmic-ray induced nucleonic cascade. Journal of Geophysical Research: Space Physics, 126, e2020JA028959.

High-altitude polar NM with the new DAQ system as a tool to study details of the cosmic-ray induced nucleonic cascade

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Author: Similä, Markus1,2; Usoskin, Ilya1,2; Poluianov, Stepan1,2;
Organizations: 1Space Physics and Astronomy Research Unit, University of Oulu, Oulu, Finland
2Sodankylä Geophysical Observatory, University of Oulu, Oulu, Finland
3Ioffe Physical-Technical Institute RAS, St. Petersburg, Russia
4Center for Space Research, North-West University, Potchefstroom, South Africa
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.8 MB)
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Language: English
Published: American Geophysical Union, 2021
Publish Date: 2021-06-30


A neutron monitor (NM) is, since the 1950s, a standard ground-based detector whose count rate reflects cosmic-ray variability. The worldwide network of NMs forms a rough spectrometer for cosmic rays. Recently, a brand-new data-acquisition (DAQ) system has been installed on the DOMC and DOMB NMs, located at the Concordia research station on the Central Antarctic plateau. The new DAQ system digitizes, at a 2-MHz sampling rate, and records all individual pulses corresponding to secondary particles in the detector. An analysis of the pulse characteristics (viz. shape, magnitude, duration, waiting time) has been performed, and several clearly distinguishable branches were identified: (A) corresponding to signal from individual secondary neutrons; (B) representing the detector's noise; (C) double pulses corresponding to the shortly separated nucleons of the same atmospheric cascades; (D) very-high multiple pulses which are likely caused by atmospheric muons; and (E) double pulses potentially caused by contamination of the neighboring detector. An analysis of the waiting-time distributions has revealed two clearly distinguishable peaks: peak (I) at about 1 ms being related to the intracascade diffusion and thermalization of secondary atmospheric neutrons; and peak (II) at 30–1,000 ms corresponding to individual atmospheric cascades. This opens a new possibility to study spectra of cosmic-ray particles in a single location as well as details of the cosmic-ray induced atmospheric cascades, using the same data set.

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Series: Journal of geophysical research. Space physics
ISSN: 2169-9380
ISSN-E: 2169-9402
ISSN-L: 2169-9380
Volume: 126
Issue: 4
Article number: e2020JA028959
DOI: 10.1029/2020JA028959
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: We are grateful to the personnel of Concordia station hosting the DOMC/DOMB instrumentation. Operation of DOMC/DOMB NMs is possible thanks to the hospitality of the Italian polar program PNRA (via the LTCPAA PNRA 2015/AC3 and the BSRN PNRA OSS-06 projects) and the French Polar Institute IPEV. It is supported by the Academy of Finland (projects CRIPA-X No. 304435, ESPERA No. 321882, QUASARE 33006​4, HEAIM-2 330427), and Finnish Antarctic Research Program (FINNARP).
Copyright information: © 2021. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.