Download Free Measurement Of The Cosmic Lepton And Electron Fluxes With The Ams Detector On Board Of The International Space Station Monitoring Of The Energy Measurement In The Calorimeter Book in PDF and EPUB Free Download. You can read online Measurement Of The Cosmic Lepton And Electron Fluxes With The Ams Detector On Board Of The International Space Station Monitoring Of The Energy Measurement In The Calorimeter and write the review.

The Alpha Magnetic Spectrometer (AMS) is a particle detector installed on the International Space Station; it starts to record data since May 2011. The experiment aims to identify the nature of charged cosmic rays and photons and measure their fluxes in the energy range of GeV to TeV. These measurements enable us to refine the cosmic ray propagation models, to perform indirect research of dark matter and to search for primordial antimatter (anti-helium). In this context, the data of the first years have been utilized to measure the electron flux and lepton flux (electron + positron) in the energy range of 0.5 GeV to 700 GeV. Identification of electrons requires an electrons / protons separation power of the order of 104, which is acquired by combining the information from different sub-detectors of AMS, in particular the electromagnetic calorimeter (ECAL), the tracker and the transition radiation detector (TRD). In this analysis, the numbers of electrons and leptons are estimated by fitting the distribution of the ECAL estimator and are verified using the TRD estimator: 11 million leptons are selected and analyzed. The systematic uncertainties are determined by changing the selection cuts and the fit procedure. The geometric acceptance of the detector and the selection efficiency are estimated thanks to simulated data. The differences observed on the control samples from data allow to correct the simulation. The systematic uncertainty associated to this correction is estimated by varying the control samples. In total, at 100 GeV (resp. 700 GeV), the statistic uncertainty of the lepton flux is 2% (30%) and the systematic uncertainty is 3% (40%). As the flux generally follows a power law as a function of energy, it is important to control the energy calibration. We have controlled in-situ the measurement of energy in the ECAL by comparing the electrons from flight data and from test beams, using in particular the E/p variable where p is momentum measured by the tracker. A second method of absolute calibration at low energy, independent from the tracker, is developed based on the geomagnetic cutoff effect. Two models of geomagnetic cutoff prediction, the Störmer approximation and the IGRF model, have been tested and compared. These two methods allow to control the energy calibration to a precision of 2% and to verify the stability of the ECAL performance with time.
The AMS-02 experiment is a particle detector installed on the International Space Station (ISS) since May 2011, which measures the characteristics of the cosmic rays to bring answers to the problematics risen by the astroparticle physics since a few decades, in particular the study of dark matter and the search of antimatter. The phenomenological aspects of the physics of cosmic rays are reviewed in a first part. A second one describes the in-flight performances of the different subdetectors of AMS-02, in particular the electromagnetic calorimeter. It is shown, using particles at the ionizing minimum (MIPs), accounting for the main part of cosmic rays, that the calorimeter works as expected, and we find the same performances as on ground. This study is used to follow in time the evolution of the detector performances. It also allows to develop a charge estimator for the nuclei using the calorimeter. A third and final part, deals with the determination of the positronic fraction. The main difficulty of this measurement is to identify the positrons by rejecting the protons thanks to the characteristics of the showers in the calorimeter. After having defined variables relevant for this separation, we build an estimator using a multivariate analysis and Monte-Carlo simulations of electrons for the higher energies. Above 100 GeV, we obtain a rejection factor of about 10 000 at a 90% efficiency. After having estimated the charge confusion, this estimator, finally, allows us to determine the positronic ratio for the first 18 months of data and energies ranging from 1.5 to 350 GeV.
Nothing provided
The soalr activity is known to influence the cosmic-ray flux on earth up to energies of 50 GeV per nucleon. The AMS-01 detector, which was flown on board the NASA Space Shuttle "Discovery" in June 1998, is sensitive to the highest energy range of solar particle events. Systematic flux fluctuations for the main cosmic-ray components (protons, helium nuclei and electrons) have been searched in the energy range accessible to the AMS-01 detector (from 100 Mev per nucleon to 200 GeV per nucleon) for the time interval for which suitable AMS-01 data are available (from June 8 to June 12, 1998). Systematic variations of cosmic-ray flux have been observed in the energy range below the geomagnetic cutoff. The comparison to the geomagnetic activity of the time has shown a correlation between systematic flux decreases and magnetic distrurbances of solar origin.
Precise measurements of primary cosmic ray Neon, Magnesium and Silicon flux is important to understand the origins and propagation properties of heavy elements in the Galaxy. This thesis presents the measurements of Neon, Magnesium, and Silicon flux in the rigidity (momentum per unit charge) range from 2.15 GV to 3 TV, with 5.6 million Ne, Mg, and Si nuclei events collected during 7 years of AMS operation (2011- 2018). The three fluxes show identical rigidity dependence above 86.5 GV, deviating from a single power law and hardening at high rigidity above 200 GV. Surprisingly, the rigidity dependence of Neon, Magnesium, and Silicon flux is different from the rigidity dependence of primary nuclei Helium, Carbon and Oxygen, even though the two groups are both primaries produced at cosmic rays sources.