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Upgrade of the mechanically pumped CO$_2$ two-phase cooling system for the alpha magnetic spectrometer on the international space station
/ Ambrosi, G (INFN, Perugia ; Perugia U.) ; Bertucci, B (INFN, Perugia ; Perugia U.) ; Bollweg, K (NASA, Houston) ; Burger, J (MIT) ; Cai, X (MIT) ; Capell, M (MIT) ; Chung, C H (Aachen, Tech. Hochsch.) ; Chuang, Y R (Northrop-Grumman) ; Clark, C (NASA, Houston) ; Ding, T (Beijing, Inst. Tech.) et al.
This study describes the successful upgrade of a mechanically pumped CO$_2$
two-phase cooling system in space by designing a new pump module for the Alpha Magnetic Spectrometer-02 on the International Space Station. Key factors for mission success are emphasized, including achieving high coolant filling accuracy within 10% of the target and maintaining system stability within ±1
C. [...]
2023
- Published in : Appl. Thermal Eng. 230 (2023) 120738
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Towards Understanding the Origin of Cosmic-Ray Electrons
/ Aguilar, M (Madrid, CIEMAT) ; Ali Cavasonza, L (IAS, Julich ; JCHP, Julich) ; Alpat, B (INFN, Perugia ; Perugia U.) ; Ambrosi, G (INFN, Perugia ; Perugia U.) ; Arruda, L (LIP, Lisbon) ; Attig, N (IAS, Julich ; JCHP, Julich) ; Azzarello, P (Geneva U.) ; Bachlechner, A (IAS, Julich ; JCHP, Julich) ; Barao, F (LIP, Lisbon) ; Barrau, A (LPSC, Grenoble) et al.
/AMS
Precision results on cosmic-ray electrons are presented in the energy range from 0.5 GeV to 1.4 TeV based on 28.1×106 electrons collected by the Alpha Magnetic Spectrometer on the International Space Station. In the entire energy range the electron and positron spectra have distinctly different magnitudes and energy dependences. [...]
2019 - 9 p.
- Published in : Phys. Rev. Lett. 122 (2019) 101101
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Towards Understanding the Origin of Cosmic-Ray Positrons
/ Aguilar, M (Madrid, CIEMAT) ; Ali Cavasonza, L (IAS, Julich ; JCHP, Julich) ; Ambrosi, G (INFN, Perugia) ; Arruda, L (LIP, Lisbon) ; Attig, N (IAS, Julich ; JCHP, Julich) ; Azzarello, P (Geneva U.) ; Bachlechner, A (IAS, Julich ; JCHP, Julich) ; Barao, F (LIP, Lisbon) ; Barrau, A (LPSC, Grenoble) ; Barrin, L (CERN) et al.
/AMS
Precision measurements of cosmic ray positrons by the Alpha Magnetic Spectrometer on the International Space Station are presented up to 1 TeV based on 1.9 million positrons.The positron flux exhibits a significant excess starting from $25.2 \pm 1.8$ GeV followed by a sharp drop-off above $284^{+91}_{-64}$ GeV.In the entire energy range the positron flux is well described by the sum of a diffuse termassociated with low energy secondary positrons produced in the collision of cosmic rays, and a new source term of high energy positrons with a finite energy cutoff. The finite cutoff energy of the source term, $E_s$, is established with a significance of more than $4 \sigma$, and it's value is determined to be $E_s = 810^{+310}_{-180}$ GeV.These experimental data on cosmic ray positrons show that, at high energies, they predominantly originate either from dark matter collisions or from new astrophysical sources..
2019 - 9 p.
- Published in : Phys. Rev. Lett. 122 (2019) 041102
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Stellar and thermal neutron capture cross section of $^9$Be
/ Wallner, A (Vienna U. ; Australian Natl. U., Canberra (main)) ; Bichler, M (Vienna, Tech. U., Atominst.) ; Coquard, L (KIT, Karlsruhe) ; Dillmann, I (KIT, Karlsruhe) ; Forstner, O (U. Vienna (main)) ; Golser, R (U. Vienna (main)) ; Heil, M (KIT, Karlsruhe) ; Käppeler, F (KIT, Karlsruhe) ; Kutschera, W (U. Vienna (main)) ; Lederer-Woods, C (Edinburgh U.) et al.
The neutron capture cross section of Be9 for stellar energies was measured via the activation technique using the Karlsruhe Van de Graaff accelerator in combination with accelerator mass spectrometry at the Vienna Environmental Research Accelerator. To characterize the energy region of interest for astrophysical applications, activations were performed in a quasistellar neutron spectrum of kT=25 keV and for a spectrum at En=473±53 keV. [...]
2019 - 11 p.
- Published in : Phys. Rev. C 99 (2019) 015804
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Observation of Fine Time Structures in the Cosmic Proton and Helium Fluxes with the Alpha Magnetic Spectrometer on the International Space Station
/ Aguilar, M (Madrid, CIEMAT) ; Ali Cavasonza, L (IAS, Julich ; JCHP, Julich) ; Alpat, B (INFN, Perugia) ; Ambrosi, G (INFN, Perugia) ; Arruda, L (LIP, Lisbon) ; Attig, N (IAS, Julich ; JCHP, Julich) ; Aupetit, S (LPSC, Grenoble) ; Azzarello, P (Geneva U.) ; Bachlechner, A (IAS, Julich ; JCHP, Julich) ; Barao, F (LIP, Lisbon) et al.
/AMS
We present the precision measurement from May 2011 to May 2017 (79 Bartels rotations) of the proton fluxes at rigidities from 1 to 60 GV and the helium fluxes from 1.9 to 60 GV based on a total of $1 \times 10^9$ events collected with the Alpha Magnetic Spectrometer aboard the International Space Station. This measurement is in solar cycle 24, which has the solar maximum in April 2014. [...]
2018 - 7 p.
- Published in : Phys. Rev. Lett. 121 (2018) 051101
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Observation of Complex Time Structures in the Cosmic-Ray Electron and Positron Fluxes with the Alpha Magnetic Spectrometer on the International Space Station
/ Aguilar, M (Madrid, CIEMAT) ; Cavasonza, L Ali (IAS, Julich ; JCHP, Julich) ; Ambrosi, G (INFN, Perugia ; Perugia U.) ; Arruda, L (LIP, Lisbon) ; Attig, N (IAS, Julich ; JCHP, Julich) ; Aupetit, S (LPSC, Grenoble) ; Azzarello, P (Geneva U.) ; Bachlechner, A (IAS, Julich ; JCHP, Julich) ; Barao, F (LIP, Lisbon) ; Barrau, A (LPSC, Grenoble) et al.
/AMS
We present high-statistics, precision measurements of the detailed time and energy dependence of the primary cosmic-ray electron flux and positron flux over 79 Bartels rotations from May 2011 to May 2017 in the energy range from 1 to 50 GeV. For the first time, the charge-sign dependent modulation during solar maximum has been investigated in detail by leptons alone. [...]
2018 - 8 p.
- Published in : Phys. Rev. Lett. 121 (2018) 051102
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Precision Measurement of Cosmic-Ray Nitrogen and its Primary and Secondary Components with the Alpha Magnetic Spectrometer on the International Space Station
/ Aguilar, M (Madrid, CIEMAT) ; Ali Cavasonza, L (IAS, Julich ; JCHP, Julich) ; Alpat, B (INFN, Perugia ; Perugia U.) ; Ambrosi, G (INFN, Perugia ; Perugia U.) ; Arruda, L (LIP, Lisbon) ; Attig, N (IAS, Julich ; JCHP, Julich) ; Aupetit, S (LPSC, Grenoble) ; Azzarello, P (Geneva U.) ; Bachlechner, A (IAS, Julich ; JCHP, Julich) ; Barao, F (LIP, Lisbon) et al.
/AMS
A precision measurement of the nitrogen flux with rigidity (momentum per unit charge) from 2.2 GV to 3.3 TV based on $2.2 \times 10^6$ events is presented. The detailed rigidity dependence of the nitrogen flux spectral index is presented for the first time. [...]
2018 - 8 p.
- Published in : Phys. Rev. Lett. 121 (2018) 051103
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Observation of New Properties of Secondary Cosmic Rays Lithium, Beryllium, and Boron by the Alpha Magnetic Spectrometer on the International Space Station
/ Aguilar, M (Madrid, CIEMAT) ; Ali Cavasonza, L (IAS, Julich ; JCHP, Julich) ; Ambrosi, G (INFN, Perugia) ; Arruda, L (LIP, Lisbon) ; Attig, N (IAS, Julich ; JCHP, Julich) ; Aupetit, S (LPSC, Grenoble) ; Azzarello, P (Geneva U.) ; Bachlechner, A (IAS, Julich ; JCHP, Julich) ; Barao, F (LIP, Lisbon) ; Barrau, A (LPSC, Grenoble) et al.
/AMS
We report on the observation of new properties of secondary cosmic rays Li, Be, and B measured in the rigidity (momentum per unit charge) range 1.9 GV to 3.3 TV with a total of $5.4 \times 10^6$ nuclei collected by AMS during the first five years of operation aboard the International Space Station. The Li and B fluxes have an identical rigidity dependence above 7 GV and all three fluxes have an identical rigidity dependence above 30 GV with the Li/Be flux ratio of $2.0 \pm 0.1$. [...]
2018 - 8 p.
- Published in : Phys. Rev. Lett. 120 (2018) 021101
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