The Neighbor Cell Deposited Energy Ratio （NCDER） is a new method that is proposed to reconstruct incidence position in a single layer for a 3-dimensional imaging electromagnetic calorimeter （ECAL）. This method was...The Neighbor Cell Deposited Energy Ratio （NCDER） is a new method that is proposed to reconstruct incidence position in a single layer for a 3-dimensional imaging electromagnetic calorimeter （ECAL）. This method was applied to reconstruct the ECAL test beam data for the Alpha Magnetic Spectrometer-02 （AMS-02）. The results show that this method can achieve an angular resolution of 7.36±0.08°/√E＋0.28±0.02° in the determination of the photon＇s direction, which is much more precise than that obtained with the commonly-adopted Center of Gravity （COG） method （8.4±0.1°/E＋0.8±0.3°）. Furthermore, since it uses only the properties of electromagnetic showers, this new method could also be used for other type of fine grain sampling calorimeters.展开更多
The electromagnetic calorimeter（ECAL） of the Alpha Magnetic Spectrometer（AMS-02） is one of the key detectors for dark matter searches. It measures the energies of electrons, positrons and photons and seperates the...The electromagnetic calorimeter（ECAL） of the Alpha Magnetic Spectrometer（AMS-02） is one of the key detectors for dark matter searches. It measures the energies of electrons, positrons and photons and seperates them from hadrons. Currently, there are 5 dead cells in the ECAL, which affect the reconstructed energy of 4.2%of total events in the ECAL acceptance. When an electromagnetic shower axis is close to the ECAL border, due to the side leakage, the reconstructed energy is affected as well. In this paper, methods for dead cells and side leakage corrections for the ECAL energy reconstruction are presented. For events with the shower axis crossing dead cells,applying dead cell correction improves the difference in the reconstructed energy from 12% to 1%, while for events near the ECAL border, with side leakage correction it is improved from 4% to 1%.展开更多
In this paper, we studied the development of hadronic shower in an electromagnetic calorimeter of Alpha Magnetic Spectrometer Ⅱ. Two parametrized empirical formulae were proposed to describe the hadronic shower shape...In this paper, we studied the development of hadronic shower in an electromagnetic calorimeter of Alpha Magnetic Spectrometer Ⅱ. Two parametrized empirical formulae were proposed to describe the hadronic shower shape in calorimeter. Using 100 GeV proton beam incident on the center of the ECAL, detailed plots of lateral and longitudinal hadronic shower behavior were given and we found the formulae can describe the development of the hadronic shower with the test beam data. The possible application of the parametrized formulae including e±-π± discrimination and tau jet reconstruction was discussed.展开更多
We develop an empirical formula to parameterize the 3-dimension （3D） distribution of electromagnetic showers in the Alpha Magnetic Spectrometer Ⅱ electromagnetic calorimeter（ECAL）. The formula was verified by ECA...We develop an empirical formula to parameterize the 3-dimension （3D） distribution of electromagnetic showers in the Alpha Magnetic Spectrometer Ⅱ electromagnetic calorimeter（ECAL）. The formula was verified by ECAL test beam data in 2002 and found to perform well. The distribution of electron showers in the ECAL are well described by the formula, which has parameters that allow one to determine the 3D shape of electromagnetic showers in the ECAL. We use this formula to correct for lateral energy leakage and dead channels in the ECAL; good results are obtained.展开更多
The effects of laser polarization on super-hot electron (> 100 keV) generation have been studied in the interaction of femtosecond laser light (800 nm, 150 fs, 6 × 10^(15) W·cm^(-2)) with a pre-formed pla...The effects of laser polarization on super-hot electron (> 100 keV) generation have been studied in the interaction of femtosecond laser light (800 nm, 150 fs, 6 × 10^(15) W·cm^(-2)) with a pre-formed plasma from a slab Cu target. For p-polarized laser pulses, high-energy γ-rays of the energy ~400keV were detected. The electron temperatures deduced from the γ-ray spectra were 66 and 52keV, respectively, in normal and reflective directions of the solid target, and hot electrons were emitted out of the plasma mainly in the normal direction. In contrast, there were nearly no γ-rays >100keV found for s-polarized laser pulses. The hot electron temperature was 26keV and the emission of hot electrons was parallel to the laser field. The superposition of resonant field with electrostatic field excited by escaping electrons may contribute to the high-energy γ-ray or super-hot electron (> 100 keV) generation.展开更多
基金Supported by China National Science Foundation(10805050)
文摘The Neighbor Cell Deposited Energy Ratio （NCDER） is a new method that is proposed to reconstruct incidence position in a single layer for a 3-dimensional imaging electromagnetic calorimeter （ECAL）. This method was applied to reconstruct the ECAL test beam data for the Alpha Magnetic Spectrometer-02 （AMS-02）. The results show that this method can achieve an angular resolution of 7.36±0.08°/√E＋0.28±0.02° in the determination of the photon＇s direction, which is much more precise than that obtained with the commonly-adopted Center of Gravity （COG） method （8.4±0.1°/E＋0.8±0.3°）. Furthermore, since it uses only the properties of electromagnetic showers, this new method could also be used for other type of fine grain sampling calorimeters.
基金Supported by National Natural Science Foundation of China(11220101004)
文摘The electromagnetic calorimeter（ECAL） of the Alpha Magnetic Spectrometer（AMS-02） is one of the key detectors for dark matter searches. It measures the energies of electrons, positrons and photons and seperates them from hadrons. Currently, there are 5 dead cells in the ECAL, which affect the reconstructed energy of 4.2%of total events in the ECAL acceptance. When an electromagnetic shower axis is close to the ECAL border, due to the side leakage, the reconstructed energy is affected as well. In this paper, methods for dead cells and side leakage corrections for the ECAL energy reconstruction are presented. For events with the shower axis crossing dead cells,applying dead cell correction improves the difference in the reconstructed energy from 12% to 1%, while for events near the ECAL border, with side leakage correction it is improved from 4% to 1%.
基金Supported by National Natural Science Foundation of China (10435070,10721140381,10099630)China Ministry of Science and Technology (2007CB16101)Chinese Academy of Sciences (KJCX2-N17,1730911111)
文摘In this paper, we studied the development of hadronic shower in an electromagnetic calorimeter of Alpha Magnetic Spectrometer Ⅱ. Two parametrized empirical formulae were proposed to describe the hadronic shower shape in calorimeter. Using 100 GeV proton beam incident on the center of the ECAL, detailed plots of lateral and longitudinal hadronic shower behavior were given and we found the formulae can describe the development of the hadronic shower with the test beam data. The possible application of the parametrized formulae including e±-π± discrimination and tau jet reconstruction was discussed.
基金Supported by NSFS(10099630),International S&T Collaboration Key Program,Ministry of Science and Technology of China
文摘We develop an empirical formula to parameterize the 3-dimension （3D） distribution of electromagnetic showers in the Alpha Magnetic Spectrometer Ⅱ electromagnetic calorimeter（ECAL）. The formula was verified by ECAL test beam data in 2002 and found to perform well. The distribution of electron showers in the ECAL are well described by the formula, which has parameters that allow one to determine the 3D shape of electromagnetic showers in the ECAL. We use this formula to correct for lateral energy leakage and dead channels in the ECAL; good results are obtained.
基金Supported by the National Natural Science Foundation of China under Grant Nos.19854001,10005014 and 19825110the National Hi-Tech ICF Programme。
文摘The effects of laser polarization on super-hot electron (> 100 keV) generation have been studied in the interaction of femtosecond laser light (800 nm, 150 fs, 6 × 10^(15) W·cm^(-2)) with a pre-formed plasma from a slab Cu target. For p-polarized laser pulses, high-energy γ-rays of the energy ~400keV were detected. The electron temperatures deduced from the γ-ray spectra were 66 and 52keV, respectively, in normal and reflective directions of the solid target, and hot electrons were emitted out of the plasma mainly in the normal direction. In contrast, there were nearly no γ-rays >100keV found for s-polarized laser pulses. The hot electron temperature was 26keV and the emission of hot electrons was parallel to the laser field. The superposition of resonant field with electrostatic field excited by escaping electrons may contribute to the high-energy γ-ray or super-hot electron (> 100 keV) generation.
