Following the decision to maintain the International Space Station (ISS) on orbit until at least 2020 (possibly until 2028) the AMS collaboration decided to correspondingly extend the lifetime of the ...experiment. Since the limited amount of helium used to cool the superconducting magnet allowed for only a limited run time of the experiment, a change from the superconducting magnet to the permanent magnet used in AMS-01 became necessary. Due to the lower magnetic field, to maintain the resolution the silicon tracker also had to be reconfigured with the installation of a silicon plane on the top of the experiment and a new plane above the electromagnetic calorimeter.
The AMS-02 experiment has been installed in May 2011 on the international space station (ISS) where it will measure, with an unprecedented accuracy, cosmic rays up to the TeV energy region for ...several years. The AMS-02 time of flight (TOF) and the anti-coincide counters (ACC) sub-detectors provide respectively the fast trigger and the veto for the data taking to the experiment. The TOF measures the particle crossing time and the absolute charge with very high precision and provides the fast trigger to AMS-02, whereas the ACC detects and vetoes particles which enter the AMS-02 volume from outside of the main detector acceptance. The electronics of the AMS-02 TOF and ACC sub-detectors have been designed to operate in space for a very long time, in extreme conditions and without any human intervention. In this paper the main design concepts of the TOF-ACC electronics, the space qualification tests and the performance are presented.
Performance of the AMS-02 transition radiation detector Doetinchem, Ph.v.; Fopp, S.; Karpinski, W. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2006, Letnik:
558, Številka:
2
Journal Article
Recenzirano
Odprti dostop
For cosmic particle spectroscopy on the International Space Station the AMS experiment will be equipped with a Transition Radiation Detector (TRD) to improve particle identification. The TRD has 20 ...layers of fleece radiator with Xe/CO
2 proportional-mode straw-tube chambers. They are supported in a conically shaped octagon structure made of CFC-Al-honeycomb. For low power consumption VA analog multiplexers are used as front-end readout. A 20 layer prototype built from final design components has achieved proton rejections from 100 to 2000 at 90% electron efficiency for proton beam energies up to 250
GeV with cluster counting, likelihood and neural net selection algorithms.
The Alpha Magnetic Spectrometer, AMS, is successfully collecting data on the International Space Station since its installation on May 19, 2011. One of the main objectives of AMS is the precision ...measurement of high energy cosmic ray electrons and positrons. The key detector for this measurement is the Electromagnetic Calorimeter. Reconstruction of electrons and positrons in the calorimeter uses a 3-dimensional shower parametrization, which accounts for the detector specifics: finite size of the calorimeter, non-uniform efficiency of the signal collection, and saturation effects due to the electronics and due to high energy density in the active calorimeter elements. This technique provides AMS with a precision energy measurement of electrons and positrons up to several TeV as well as an excellent rejection of the proton background.
Precision measurements by the Alpha Magnetic Spectrometer (AMS) on the International Space Station of 3He and 4He fluxes are presented. The measurements are based on 100 million 4He nuclei in the ...rigidity range from 2.1 to 21 GV and 18 million 3He from 1.9 to 15 GV collected from May 2011 to November 2017. We observed that the 3He and 4He fluxes exhibit nearly identical variations with time. The relative magnitude of the variations decreases with increasing rigidity. The rigidity dependence of the 3He/4He flux ratio is measured for the first time. Below 4 GV, the 3He/4He flux ratio was found to have a significant long-term time dependence. Above 4 GV, the 3He/4He 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.
A precision measurement of
τ polarisation at LEP tests neutral couplings of
τ leptons providing therefore a stringent test of the Standard Model predictions. The polarisation measurement using ...leptonic
τ decays which constitute an important part of this analysis is discussed with a special emphasis on the analysis of the systematic errors. This measurement is based on approximately 600 000 Z →
τ
+
τ
− decays collected by the four LEP experiments during the 1990–1994 running periods.
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, Letnik:
540, Številka:
1
Journal Article
Recenzirano
Odprti dostop
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.
The AMS-02 TRD for the international space station Hauler, F.; Bartoloni, A.; Becker, U. ...
IEEE transactions on nuclear science,
2004-Aug., 2004-08-00, 20040801, Letnik:
51, Številka:
4
Journal Article
Recenzirano
The Alpha Magnetic Spectrometer (AMS-02) is an experiment which will be mounted on the international space station (ISS) to measure primary cosmic ray spectra in space. A key element is the ...transition radiation detector (TRD) to extract an e/sup +/ or p/sup -/ signal reducing the p/sup +/ or e/sup -/ background by a rejection factor 10/sup 2/--10/sup 3/ in an energy range from 10 to 300 GeV. This will be used in combination with an electromagnetic calorimeter to provide overall p/sup +/ rejection of 10/sup 6/ at 90% e/sup +/ efficiency. The detector consists of 20 layers of 6 mm diameter straw tubes alternating with 20 mm layers of polyethylene/polypropylene fleece radiator. The tubes are filled with a 4:1 mixture of Xe:CO/sub 2/ at 1 bar absolute pressure from a recirculating gas system designed to operate >3 years in space. There are in total 5248 straw tubes which are read out by a custom-made DAQ system in less than 80 /spl mu/s. The electronics must be low in power consumption and sustain the stringent requirements of operation in space. The construction of the detector and its electronics is presented in this paper.
Precision measurements by the Alpha Magnetic Spectrometer (AMS) on the International Space Station of the deuteron ( D ) flux are presented. The measurements are based on 21 × 10 6 D nuclei in the ...rigidity range from 1.9 to 21 GV collected from May 2011 to April 2021. We observe that over the entire rigidity range the D flux exhibits nearly identical time variations with the p , He 3 , and He 4 fluxes. Above 4.5 GV, the D / He 4 flux ratio is time independent and its rigidity dependence is well described by a single power law ∝ R Δ with Δ D / He 4 = − 0.108 ± 0.005 . This is in contrast with the He 3 / He 4 flux ratio for which we find Δ He 3 / He 4 = − 0.289 ± 0.003 . Above ∼ 13 GV we find a nearly identical rigidity dependence of the D and p fluxes with a D / p flux ratio of 0.027 ± 0.001 . These unexpected observations indicate that cosmic deuterons have a sizable primarylike component. With a method independent of cosmic ray propagation, we obtain the primary component of the D flux equal to 9.4 ± 0.5 % of the He 4 flux and the secondary component of the D flux equal to 58 ± 5 % of the He 3 flux. Published by the American Physical Society 2024
Neutral couplings of the τ lepton Kounine, A.
Nuclear physics. Section B, Proceedings supplement,
03/1995, Letnik:
40, Številka:
1
Journal Article
Recenzirano
The precision electroweak measurements at LEP allow for a stringent test of the Standard Model predictions at the level of quantum corrections. Important information comes from the measurements ...involving
τ's. Recent results from LEP on the Z Boson lineshape,
τ polarization and forward-backward charge asymmetry of
τ pairs are reviewed. They are based on approximately 350 000
Z →
τ
+
τ
− decays collected by the four LEP experiments in 1990–1993 running periods.
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