32 research outputs found
The internal alignment and position resolution of the AMS-02 silicon tracker determined with cosmic-ray muons
Abstract 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
Measurement of low-energy antiproton detection efficiency in BESS below 1 GeV
An accelerator experiment was performed using a low-energy antiproton beam to
measure antiproton detection efficiency of BESS, a balloon-borne spectrometer
with a superconducting solenoid. Measured efficiencies showed good agreement
with calculated ones derived from the BESS Monte Carlo simulation based on
GEANT/GHEISHA. With detailed verification of the BESS simulation, the relative
systematic error of detection efficiency derived from the BESS simulation has
been determined to be 5%, compared with the previous estimation of
15% which was the dominant uncertainty for measurements of cosmic-ray
antiproton flux.Comment: 13 pages, 7 figure
Measurements of atmospheric muon spectra at mountain altitude
We report new measurements of the atmospheric muons at mountain altitude. The
measurement was carried out with the BESS detector at the top of Mt. Norikura,
Japan. The altitude is 2,770 m above sea level. Comparing our results and
predictions given by some interaction models, a further appropriate model has
been investigated. These studies would improve accuracy of atmospheric neutrino
calculations.Comment: Mean momentum in Table 1 was correcte
Measurements of Cosmic-ray Low-energy Antiproton and Proton Spectra in a Transient Period of the Solar Field Reversal
The energy spectra of cosmic-ray low-energy antiprotons and protons have been
measured by BESS in 1999 and 2000, during a period covering the solar magnetic
field reversal. Based on these measurements, a sudden increase of the
antiproton to proton flux ratio following the solar magnetic field reversal was
observed, and it generally agrees with a drift model of the solar modulation.Comment: 4 pages, 4 figures, revised version accepted for publication in Phys.
Rev. Let
Improving the absolute accuracy of the gravitational wave detectors by combining the photon pressure and gravity field calibrators
Solar Modulation of Low-Energy Antiproton and Proton Spectra Measured by BESS
The spectra of low-energy cosmic-ray protons and antiprotons have been measured by BESS in nine high-latitude balloon flights between 1993 and 2004. These measurements span a range of solar activity from the previous solar minimum through solar ma>:im%am and the onset of the present solar minimum, as well as a solar magnetic field reversal from positive to negative in 2000. Because protons and antiprotons differ only in charge sign, these simultaneous measurements provide a sensitive probe of charge dependent solar modulation. The antiproton to proton ratio measured by BESS is consistent with simple spherically symmetric models of solar modulation during the Sun's positive polarity phase, but favor charge-sign-dependent drift models during the negative phase. The BESS measurements will be presented and compared to various models of solar modulation
Prospects for improving the sensitivity of the cryogenic gravitational wave detector KAGRA
International audienceUpgrades to improve the sensitivity of gravitational wave detectors enable more frequent detections and more precise source parameter estimation. Unlike other advanced interferometric detectors such as Advanced LIGO and Advanced Virgo, KAGRA requires a different approach for the upgrade since it is the only detector which employs cryogenic cooling of the test masses. In this paper, we describe possible KAGRA upgrades with technologies focusing on different detector bands and compare the impacts on the detection of compact binary coalescences. We show that either fivefold improvement in the 100 M⊙–100 M⊙ binary black hole range, a factor of 1.3 improvement in the binary neutron star range, or a factor of 1.7 improvement in the sky localization of binary neutron stars is quite feasible with upgrades that do not require changes in the existing cryogenic or vacuum infrastructure. We also show that twofold broadband sensitivity improvement is possible by applying multiple upgrades to the detector