Methods for Tracking Cosmic-Ray Spectral Changes Using Neutron Monitors at High Cutoff Rigidity
Neutron monitors are a standard tool for high-precision monitoring of changes in the Galactic cosmic ray (GCR) flux that occur as a result of variations of the heliospheric conditions and solar storms. In Thailand, we have developed a mobile neutron monitor named “Changvan” based on the 3NM64 design...
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2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adc5f9 |
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| author | S. Khamphakdee W. Nuntiyakul C. Banglieng A. Seripienlert P. Yakum A. Sáiz D. Ruffolo P. Evenson K. Munakata S. Komonjinda |
| author_facet | S. Khamphakdee W. Nuntiyakul C. Banglieng A. Seripienlert P. Yakum A. Sáiz D. Ruffolo P. Evenson K. Munakata S. Komonjinda |
| author_sort | S. Khamphakdee |
| collection | DOAJ |
| description | Neutron monitors are a standard tool for high-precision monitoring of changes in the Galactic cosmic ray (GCR) flux that occur as a result of variations of the heliospheric conditions and solar storms. In Thailand, we have developed a mobile neutron monitor named “Changvan” based on the 3NM64 design, except that the middle counter lacks lead producer rings, so we call it a semileaded neutron monitor. From 2021 April to 2023 April, the Changvan operated at the Science and Technology Park, Mae Hia, Chiang Mai, Thailand, at an altitude of about 340 m above sea level, with a vertical cutoff rigidity of 16.7 GV, which is near the highest value observed globally. With a similar cutoff rigidity, the nearby Princess Sirindhorn Neutron Monitor is an 18NM64 at the summit of Doi Inthanon, the highest mountain in Thailand, at 2560 m above sea level. We examine how count rates at different altitudes with similar cutoffs, count rates from the unleaded versus leaded counters, and the leader fraction measured from time-delay histograms all reflect GCR spectral differences, thus providing a variety of techniques for tracking cosmic-ray spectral changes. Applied at high cutoff rigidity, these methods extend the reach of the worldwide neutron monitor network to even higher rigidity. |
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| institution | OA Journals |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-c1fd680146cf447ab5bed1ceb019e3a32025-08-20T02:28:19ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198415110.3847/1538-4357/adc5f9Methods for Tracking Cosmic-Ray Spectral Changes Using Neutron Monitors at High Cutoff RigidityS. Khamphakdee0https://orcid.org/0009-0008-8182-1180W. Nuntiyakul1https://orcid.org/0000-0002-1664-5845C. Banglieng2https://orcid.org/0000-0002-4862-2015A. Seripienlert3https://orcid.org/0000-0002-3764-8949P. Yakum4https://orcid.org/0009-0000-7520-3038A. Sáiz5https://orcid.org/0000-0001-7771-4341D. Ruffolo6https://orcid.org/0000-0003-3414-9666P. Evenson7https://orcid.org/0000-0001-7929-810XK. Munakata8https://orcid.org/0000-0002-2131-4100S. Komonjinda9https://orcid.org/0000-0001-7987-017XGraduate Program in Astronomy, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University , Chiang Mai 50200, ThailandDepartment of Physics and Materials Science, Faculty of Science, Chiang Mai University , Chiang Mai 50200, Thailand ; waraporn.n@cmu.ac.thDivision of Physics, Faculty of Science and Technology, Rajamangala University of Technology Thanyaburi , Pathum Thani 12110, ThailandOffice of Research Administration, Chiang Mai University , Chiang Mai 50200, ThailandGraduate Program in Astronomy, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University , Chiang Mai 50200, ThailandDepartment of Physics, Faculty of Science, Mahidol University , Bangkok 10400, ThailandDepartment of Physics, Faculty of Science, Mahidol University , Bangkok 10400, ThailandDepartment of Physics and Astronomy, University of Delaware , Newark, DE 19716, USAPhysics Department, Shinshu University , Matsumoto, Nagano 390-8621, JapanDepartment of Physics and Materials Science, Faculty of Science, Chiang Mai University , Chiang Mai 50200, Thailand ; waraporn.n@cmu.ac.thNeutron monitors are a standard tool for high-precision monitoring of changes in the Galactic cosmic ray (GCR) flux that occur as a result of variations of the heliospheric conditions and solar storms. In Thailand, we have developed a mobile neutron monitor named “Changvan” based on the 3NM64 design, except that the middle counter lacks lead producer rings, so we call it a semileaded neutron monitor. From 2021 April to 2023 April, the Changvan operated at the Science and Technology Park, Mae Hia, Chiang Mai, Thailand, at an altitude of about 340 m above sea level, with a vertical cutoff rigidity of 16.7 GV, which is near the highest value observed globally. With a similar cutoff rigidity, the nearby Princess Sirindhorn Neutron Monitor is an 18NM64 at the summit of Doi Inthanon, the highest mountain in Thailand, at 2560 m above sea level. We examine how count rates at different altitudes with similar cutoffs, count rates from the unleaded versus leaded counters, and the leader fraction measured from time-delay histograms all reflect GCR spectral differences, thus providing a variety of techniques for tracking cosmic-ray spectral changes. Applied at high cutoff rigidity, these methods extend the reach of the worldwide neutron monitor network to even higher rigidity.https://doi.org/10.3847/1538-4357/adc5f9Cosmic ray detectorsGalactic cosmic raysSpace weatherSolar-terrestrial interactions |
| spellingShingle | S. Khamphakdee W. Nuntiyakul C. Banglieng A. Seripienlert P. Yakum A. Sáiz D. Ruffolo P. Evenson K. Munakata S. Komonjinda Methods for Tracking Cosmic-Ray Spectral Changes Using Neutron Monitors at High Cutoff Rigidity The Astrophysical Journal Cosmic ray detectors Galactic cosmic rays Space weather Solar-terrestrial interactions |
| title | Methods for Tracking Cosmic-Ray Spectral Changes Using Neutron Monitors at High Cutoff Rigidity |
| title_full | Methods for Tracking Cosmic-Ray Spectral Changes Using Neutron Monitors at High Cutoff Rigidity |
| title_fullStr | Methods for Tracking Cosmic-Ray Spectral Changes Using Neutron Monitors at High Cutoff Rigidity |
| title_full_unstemmed | Methods for Tracking Cosmic-Ray Spectral Changes Using Neutron Monitors at High Cutoff Rigidity |
| title_short | Methods for Tracking Cosmic-Ray Spectral Changes Using Neutron Monitors at High Cutoff Rigidity |
| title_sort | methods for tracking cosmic ray spectral changes using neutron monitors at high cutoff rigidity |
| topic | Cosmic ray detectors Galactic cosmic rays Space weather Solar-terrestrial interactions |
| url | https://doi.org/10.3847/1538-4357/adc5f9 |
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