摘要
The Alpha Magnetic Spectrometer（AMS-02）,which is installed on the International Space Station（ISS）,has been collecting data successfully since May 2011.The main goals of AMS-02 are the search for cosmic anti-matter,dark matter and the precise measurement of the relative abundance of elements and isotopes in galactic cosmic rays.In order to identify particle properties,AMS-02 includes several specialized sub-detectors.Among these,the AMS-02 Ring Imaging Cherenkov detector（RICH） is designed to provide a very precise measurement of the velocity and electric charge of particles.We describe a method to reject the dominant electron background in antiproton identification with the use of the AMS-02 RICH detector as a veto for rigidities below 3 GV.A ray tracing integration method is used to maximize the statistics of with the lowest possible e background,providing 4 times rejection power gain for e background with respect to only 3% of signal efficiency loss.By using the collected cosmic-ray data,e contamination can be well suppressed within 3% with β ≈ 1,while keeping 76% efficiency for below the threshold.
The Alpha Magnetic Spectrometer（AMS-02）,which is installed on the International Space Station（ISS）,has been collecting data successfully since May 2011.The main goals of AMS-02 are the search for cosmic anti-matter,dark matter and the precise measurement of the relative abundance of elements and isotopes in galactic cosmic rays.In order to identify particle properties,AMS-02 includes several specialized sub-detectors.Among these,the AMS-02 Ring Imaging Cherenkov detector（RICH） is designed to provide a very precise measurement of the velocity and electric charge of particles.We describe a method to reject the dominant electron background in antiproton identification with the use of the AMS-02 RICH detector as a veto for rigidities below 3 GV.A ray tracing integration method is used to maximize the statistics of with the lowest possible e background,providing 4 times rejection power gain for e background with respect to only 3% of signal efficiency loss.By using the collected cosmic-ray data,e contamination can be well suppressed within 3% with β ≈ 1,while keeping 76% efficiency for below the threshold.
基金
Supported by China Scholarship Council(CSC)under Grant No.201306380027
