Properties of Cosmic Helium Isotopes Measured by the Alpha Magnetic Spectrometer

AMS Collaboration

doi:10.1103/PhysRevLett.123.181102

Properties of Cosmic Helium Isotopes Measured by the Alpha Magnetic Spectrometer

AMS Collaboration

Department of Physics

Research output: Contribution to journal › Article › peer-review

60 Citations (Scopus)

Abstract

Precision measurements by the Alpha Magnetic Spectrometer (AMS) on the International Space Station of He3 and He4 fluxes are presented. The measurements are based on 100 million He4 nuclei in the rigidity range from 2.1 to 21 GV and 18 million He3 from 1.9 to 15 GV collected from May 2011 to November 2017. We observed that the He3 and He4 fluxes exhibit nearly identical variations with time. The relative magnitude of the variations decreases with increasing rigidity. The rigidity dependence of the He3/He4 flux ratio is measured for the first time. Below 4 GV, the He3/He4 flux ratio was found to have a significant long-term time dependence. Above 4 GV, the He3/He4 flux ratio was found to be time independent, and its rigidity dependence is well described by a single power law ∈RΔ with Δ=-0.294±0.004. Unexpectedly, this value is in agreement with the B/O and B/C spectral indices at high energies.

Original language	English
Article number	181102
Journal	Physical review letters
Volume	123
Issue number	18
DOIs	https://doi.org/10.1103/PhysRevLett.123.181102
Publication status	Published - 2019 Nov 1

All Science Journal Classification (ASJC) codes

General Physics and Astronomy

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10.1103/PhysRevLett.123.181102

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@article{88259d1e833b474981f7bc29b5269647,

title = "Properties of Cosmic Helium Isotopes Measured by the Alpha Magnetic Spectrometer",

abstract = "Precision measurements by the Alpha Magnetic Spectrometer (AMS) on the International Space Station of He3 and He4 fluxes are presented. The measurements are based on 100 million He4 nuclei in the rigidity range from 2.1 to 21 GV and 18 million He3 from 1.9 to 15 GV collected from May 2011 to November 2017. We observed that the He3 and He4 fluxes exhibit nearly identical variations with time. The relative magnitude of the variations decreases with increasing rigidity. The rigidity dependence of the He3/He4 flux ratio is measured for the first time. Below 4 GV, the He3/He4 flux ratio was found to have a significant long-term time dependence. Above 4 GV, the He3/He4 flux ratio was found to be time independent, and its rigidity dependence is well described by a single power law ∈RΔ with Δ=-0.294±0.004. Unexpectedly, this value is in agreement with the B/O and B/C spectral indices at high energies.",

author = "{AMS Collaboration} and M. Aguilar and {Ali Cavasonza}, L. and G. Ambrosi and L. Arruda and N. Attig and A. Bachlechner and F. Barao and A. Barrau and L. Barrin and A. Bartoloni and {Ba{\c s}eǧmez-Du Pree}, S. and R. Battiston and U. Becker and M. Behlmann and B. Beischer and J. Berdugo and B. Bertucci and V. Bindi and {De Boer}, W. and K. Bollweg and B. Borgia and Boschini, {M. J.} and M. Bourquin and Bueno, {E. F.} and J. Burger and Burger, {W. J.} and Cai, {X. D.} and M. Capell and S. Caroff and J. Casaus and G. Castellini and F. Cervelli and Chang, {Y. H.} and Chen, {G. M.} and Chen, {H. S.} and Y. Chen and L. Cheng and Chou, {H. Y.} and V. Choutko and Chung, {C. H.} and C. Clark and G. Coignet and C. Consolandi and A. Contin and C. Corti and Z. Cui and K. Dadzie and Dai, {Y. M.} and A. Datta and Y. Yang",

note = "Publisher Copyright: {\textcopyright} 2019 authors. Published by the American Physical Society.",

year = "2019",

month = nov,

day = "1",

doi = "10.1103/PhysRevLett.123.181102",

language = "English",

volume = "123",

journal = "Physical review letters",

issn = "0031-9007",

publisher = "American Physical Society",

number = "18",

}

TY - JOUR

T1 - Properties of Cosmic Helium Isotopes Measured by the Alpha Magnetic Spectrometer

AU - AMS Collaboration

AU - Aguilar, M.

AU - Ali Cavasonza, L.

AU - Ambrosi, G.

AU - Arruda, L.

AU - Attig, N.

AU - Bachlechner, A.

AU - Barao, F.

AU - Barrau, A.

AU - Barrin, L.

AU - Bartoloni, A.

AU - Başeǧmez-Du Pree, S.

AU - Battiston, R.

AU - Becker, U.

AU - Behlmann, M.

AU - Beischer, B.

AU - Berdugo, J.

AU - Bertucci, B.

AU - Bindi, V.

AU - De Boer, W.

AU - Bollweg, K.

AU - Borgia, B.

AU - Boschini, M. J.

AU - Bourquin, M.

AU - Bueno, E. F.

AU - Burger, J.

AU - Burger, W. J.

AU - Cai, X. D.

AU - Capell, M.

AU - Caroff, S.

AU - Casaus, J.

AU - Castellini, G.

AU - Cervelli, F.

AU - Chang, Y. H.

AU - Chen, G. M.

AU - Chen, H. S.

AU - Chen, Y.

AU - Cheng, L.

AU - Chou, H. Y.

AU - Choutko, V.

AU - Chung, C. H.

AU - Clark, C.

AU - Coignet, G.

AU - Consolandi, C.

AU - Contin, A.

AU - Corti, C.

AU - Cui, Z.

AU - Dadzie, K.

AU - Dai, Y. M.

AU - Datta, A.

AU - Yang, Y.

PY - 2019/11/1

Y1 - 2019/11/1

N2 - Precision measurements by the Alpha Magnetic Spectrometer (AMS) on the International Space Station of He3 and He4 fluxes are presented. The measurements are based on 100 million He4 nuclei in the rigidity range from 2.1 to 21 GV and 18 million He3 from 1.9 to 15 GV collected from May 2011 to November 2017. We observed that the He3 and He4 fluxes exhibit nearly identical variations with time. The relative magnitude of the variations decreases with increasing rigidity. The rigidity dependence of the He3/He4 flux ratio is measured for the first time. Below 4 GV, the He3/He4 flux ratio was found to have a significant long-term time dependence. Above 4 GV, the He3/He4 flux ratio was found to be time independent, and its rigidity dependence is well described by a single power law ∈RΔ with Δ=-0.294±0.004. Unexpectedly, this value is in agreement with the B/O and B/C spectral indices at high energies.

AB - Precision measurements by the Alpha Magnetic Spectrometer (AMS) on the International Space Station of He3 and He4 fluxes are presented. The measurements are based on 100 million He4 nuclei in the rigidity range from 2.1 to 21 GV and 18 million He3 from 1.9 to 15 GV collected from May 2011 to November 2017. We observed that the He3 and He4 fluxes exhibit nearly identical variations with time. The relative magnitude of the variations decreases with increasing rigidity. The rigidity dependence of the He3/He4 flux ratio is measured for the first time. Below 4 GV, the He3/He4 flux ratio was found to have a significant long-term time dependence. Above 4 GV, the He3/He4 flux ratio was found to be time independent, and its rigidity dependence is well described by a single power law ∈RΔ with Δ=-0.294±0.004. Unexpectedly, this value is in agreement with the B/O and B/C spectral indices at high energies.

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U2 - 10.1103/PhysRevLett.123.181102

DO - 10.1103/PhysRevLett.123.181102

M3 - Article

C2 - 31763896

AN - SCOPUS:85074894958

SN - 0031-9007

VL - 123

JO - Physical review letters

JF - Physical review letters

IS - 18

M1 - 181102

ER -

Properties of Cosmic Helium Isotopes Measured by the Alpha Magnetic Spectrometer

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