Cosmic rays’ interactions with the residual atmosphere surrounding the Earth produce a variety of particles, like electrons, positrons, protons, anti-protons, and Helium nuclei that can be observed ...below the local geomagnetic cutoff. In this work, we present new measurements of downward-going, albedo proton fluxes with kinetic energy in the range ∼40–∼250 MeV, performed by the High-Energy Particle Detector (HEPD-01) on board of the China Seismo-Electromagnetic Satellite - CSES-01 - at an altitude of ∼500 km. Employing a dedicated trajectory-tracing simulation routine, the protons collected by HEPD-01 are classified into quasi-trapped (QT), long lifetime (≳10 s) particles concentrating in the equatorial region of the Earth, and un-trapped (UT), distributed at all latitudes; the latter includes both precipitating short lifetime particles (UTS) and pseudo-trapped long lifetime (UTL) populations, abundant in the so-called penumbra regions. The temporal trend of re-entrant protons between 2018 and 2022 is also reported, assessing the stability of such population during the data-taking period of HEPD-01; this highlights their independence from the long-term modulating effect of the solar activity.
•A study of re-entrant albedo protons in the Earth’s magnetosphere as a function of energy with the HEPD-01 payload is presented.•A comparison with past experiments is carried out, with good results.•Time-profiles of re-entrant albedo protons show a general stability during the analyzed period.
Accurate measurements of under cutoff proton fluxes in the energy range 0.07–9.1 GeV have been performed with the Alpha Magnetic Spectrometer (AMS) at altitudes of 370–390 km in the geographic ...latitude interval ±51.7°. A clear transition from a Stably Trapped population typical of the Inner Van Allen belts, in the region of the South Atlantic Anomaly (SAA), to a Quasi‐Trapped population in the regions underneath the Van Allen belts outside the SAA is observed. The flux maps as a function of the canonical adiabatic variables L, αo, and energy E are presented and discussed.
Charge determination of nuclei with the AMS-02 silicon tracker Alpat, B.; Ambrosi, G.; Azzarello, Ph ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2005, Volume:
540, Issue:
1
Journal Article
Peer reviewed
Open access
The silicon tracker of the AMS-02 detector measures the trajectory in three dimensions of electrons, protons and nuclei to high precision in a dipole magnetic field and thus measures their rigidity ...(momentum over charge) and the sign of their charge. In addition, it measures the specific energy loss of charged particles to determine the charge magnitude. Ladders from the AMS-02 tracker have been exposed to ion beams at CERN and GSI to study their response to nuclei from helium up to the iron group. The longest ladder,
72
×
496
mm
2
, verified in the tests contains 12 sensors. Good charge resolution is observed up to iron.
Accurate measurements of electron and positron fluxes in the energy range 0.2–10 GeV have been performed with the Alpha Magnetic Spectrometer (AMS) at altitudes of 320–390 km in the geographic ...latitude interval ±51.7°. We focus on the fluxes measured in the regions nearby the South Atlantic Anomaly, defined by the local magnetic values of the magnetic field B (0.21 ≤ B ≤ 0.26 G) at the altitude of AMS. A clear transition from the Stably Trapped population typical of the Inner Van Allen belts to Quasi‐Trapped population in the regions underneath the Van Allen belts is observed. The high energy observations demonstrate the relatively higher abundance of positrons in the Inner Van Allen belts, for both the Stably Trapped and the Quasi‐Trapped populations. The flux maps as a function of the canonical adiabatic variables L, αo are presented for the interval 0.95 < L < 3, 0° < αo < 90° for electron energies below 10 GeV and positrons energies below 3 GeV. The results are compared with existing data at lower energies.
Bent silicon crystals mounted on high-accuracy angular actuators were installed in the CERN Super Proton Synchrotron (SPS) and extensively tested to assess the feasibility of crystal-assisted ...collimation in circular hadron colliders. The adopted layout was exploited and regularly upgraded for about a decade by the UA9 Collaboration. The investigations provided the compelling evidence of a strong reduction of beam losses induced by nuclear inelastic interactions in the aligned crystals in comparison with amorphous orientation. A conceptually similar device, installed in the betatron cleaning insertion of CERN Large Hadron Collider (LHC), was operated through the complete acceleration and storage cycle and demonstrated a large reduction of the background leaking from the collimation region and radiated into the cold sections of the accelerator and the experimental detectors. The implemented layout and the relevant results of the beam tests performed in the SPS and in the LHC with stored proton and ion beams are extensively discussed.
A measurement of the cosmic ray positron fraction e+/(e++e−) in the energy range of 1–30 GeV is presented. The measurement is based on data taken by the AMS-01 experiment during its 10 day Space ...Shuttle flight in June 1998. A proton background suppression on the order of 106 is reached by identifying converted bremsstrahlung photons emitted from positrons.
For the first time, accurate measurements of electron and positron fluxes in the energy range 0.2–10 GeV have been performed with the Alpha Magnetic Spectrometer (AMS) at altitudes of 370–390 km in ...the geographic latitude interval ±51.7°. We describe the observed under‐cutoff lepton fluxes outside the region of the South Atlantic Anomaly. The separation in quasi‐trapped, long‐lifetime (O(10 s)), and albedo, short‐lifetime (O(100 ms)), components is explained in terms of the drift shell populations observed by AMS. A significantly higher relative abundance of positrons with respect to electrons is seen in the quasi‐trapped population. The flux maps as a function of the canonical adiabatic variables L, α0 are presented for the interval 0.95 < L < 3, 0° < α0 < 90° for electrons (E < 10 GeV) and positrons (E < 3 GeV). The results are compared to existing data at lower energies. The properties of the observed under‐cutoff particles are also investigated in terms of their residence times and geographical origin.
The Alpha Magnetic Spectrometer is a large acceptance cosmic-ray detector
(
0.5
m
2
sr
)
designed to operate at an altitude of 400
km on the International Space Station. The AMS-02 silicon tracker ...contains 2264 silicon microstrip sensors (total active area
6.75
m
2
). The internal alignment parameters of the assembled tracker have been determined on the ground with cosmic-ray muons. The alignment procedure is described and results for the alignment precision and position resolution are reported.
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