Properties of Cosmic Helium Isotopes Measured by the Alpha Magnetic Spectrometer

Aguilar, M.; Cavasonza, L.; Ambrosi, G.; Arruda, L.; Attig, N.; Bachlechner, A.; Barao, F.; Barrau, A.; Barrin, L.; Bartoloni, A.; Basegmez-du Pree, S.; Battiston, R.; Becker, U.; Behlmann, M.; Beischer, B.; Berdugo, J.; Bertucci, B.; Bindi, V.; de Boer, W.; Bollweg, K.; Borgia, B.; Boschini, M.; Bourquin, M.; Bueno, E.; Burger, J.; Burger, W.; Cai, X.; Capell, M.; Caroff, S.; Casaus, J.; Castellini, G.; Cervelli, F.; Chang, Y.; Chen, G.; Chen, H.; Chen, Y.; Cheng, L.; Chou, H.; Choutko, V.; Chung, C.; Clark, C.; Coignet, G.; Consolandi, C.; Contin, A.; Corti, C.; Cui, Z.; Dadzie, K.; Dai, Y.; Datta, A.; Delgado, C.; Della Torre, S.; DEMİRKÖZ, MELAHAT; Derome, L.; Di Falco, S.; Di Felice, V.; Diaz, C.; Dimiccoli, F.; von Doetinchem, P.; Dong, F.; Donnini, F.; Duranti, M.; Egorov, A.; Eline, A.; Feng, J.; Fiandrini, E.; Fisher, P.; Formato, V.; Galaktionov, Y.; Gamez, C.; Garcia-Lopez, R.; Gargiulo, C.; Gast, H.; Gebauer, I.; Gervasi, M.; Giovacchini, F.; Gomez-Coral, D.; Gong, J.; Goy, C.; Grabski, V.; Grandi, D.; Graziani, M.; Guo, K.; Haino, S.; Han, K.; He, Z.; Hsieh, T.; Huang, H.; Huang, Z.; Incagli, M.; Jang, W.; Jia, Yi; Jinchi, H.; Kanishev, K.; Khiali, B.; Kim, G.; Kirn, Th.; Konyushikhin, M.; Kounina, O.; Kounine, A.; Koutsenko, V.; Kulemzin, A.; La Vacca, G.; Laudi, E.; Laurenti, G.; Lazzizzera, I.; Lebedev, A.; Lee, H.; Lee, S.; Li, J.; Li, Q.; Li, T.; Li, Z.; Light, C.; Lin, C.; Lippert, T.; Liu, Z.; Lu, S.; Lu, Y.; Luebelsmeyer, K.; Luo, F.; Luo, J.; Luo, Xi; Lyu, S.; Machate, F.; Mana, C.; Marin, J.; Martin, T.; Martinez, G.; Masi, N.; Maurin, D.; Menchaca-Rocha, A.; Meng, Q.; Mo, D.; Molero, M.; Mott, P.; Mussolin, L.; Nelson, T.; Ni, J.; Nikonov, N.; Nozzoli, F.; Oliva, A.; Orcinha, M.; Palermo, M.; Palmonari, F.; Paniccia, M.; Pashnin, A.; Pauluzzi, M.; Pensotti, S.; Phan, H.; Plyaskin, V.; Poireau, V.; Poluianov, S.; Popkow, A.; Qi, X.; Qin, X.; Qu, Z.; Quadrani, L.; Rancoita, P.; Rapin, D.; Reina Conde, A.; Rosier-Lees, S.; Rozhkov, A.; Rozza, D.; Sagdeev, R.; Schael, S.; Schmidt, S.; von Dratzig, A.; Schwering, G.; Seo, E.; Shan, B.; Shi, J.; Siedenburg, T.; Solano, C.; Song, J.; Sun, Z.; Tacconi, M.; Tang, X.; Tang, Z.; Tian, J.; Ting, Samuel; Ting, S.; Tomassetti, N.; Torsti, J.; Tuysuz, C.; Urban, T.; Usoskin, I.; Vagelli, V.; Vainio, R.; Valente, E.; Valtonen, E.; Vazquez Acosta, M.; Vecchi, M.; Velasco, M.; Vialle, J.; Wang, L.; Wang, N.; Wang, Q.; Wang, X.; Wang, X.; Wang, Z.; Wei, J.; Weng, Z.; Wu, H.; Xiong, R.; Xu, W.; Yan, Q.; Yang, Y.; Yi, H.; Yu, Y.; Yu, Z.; Zannoni, M.; Zeissler, S.; Zhang, C.; Zhang, F.; Zhang, J.; Zhang, Z.; Zhao, F.; Zheng, Z.; Zhuang, H.; Zhukov, V.; Zichichi, A.; Zimmermann, N.; Zuccon, P.

doi:10.1103/physrevlett.123.181102

Properties of Cosmic Helium Isotopes Measured by the Alpha Magnetic Spectrometer

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Aguilar M., Cavasonza L. A., Ambrosi G., Arruda L., Attig N., Bachlechner A., ...More

PHYSICAL REVIEW LETTERS, vol.123, no.18, 2019 (SCI-Expanded)

Publication Type: Article / Article
Volume: 123 Issue: 18
Publication Date: 2019
Doi Number: 10.1103/physrevlett.123.181102
Journal Name: PHYSICAL REVIEW LETTERS
Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
Middle East Technical University Affiliated: Yes

Abstract

Precision measurements by the Alpha Magnetic Spectrometer (AMS) on the International Space Station of He-3 and He-4 fluxes are presented. The measurements are based on 100 million He-4 nuclei in the rigidity range from 2.1 to 21 GV and 18 million He-3 from 1.9 to 15 GV collected from May 2011 to November 2017. We observed that the He-3 and He-4 fluxes exhibit nearly identical variations with time. The relative magnitude of the variations decreases with increasing rigidity. The rigidity dependence of the He-3/He-4 flux ratio is measured for the first time. Below 4 GV, the He-3/He-4 flux ratio was found to have a significant long-term time dependence. Above 4 GV, the He-3/He-4 flux ratio was found to be time independent, and its rigidity dependence is well described by a single power law proportional to R-Delta with Delta = 0.294 0.004. Unexpectedly, this value is in agreement with the B/O and B/C spectral indices at high energies.