Recent works on AMS TANG Zhi-Cheng
Outline Detector overview Proton measurement
Detector overview to check and monitor the situation and performance of AMS detector from fly data Based on statistics of detector hit distribution and reco object distribution Run automatically at CERN LSF
Accumulate data plots daily data rate accumulate events number daily event number
AMS fly overview Live time No. of events Fly time
Hits distribution of sub-detectors(1)
Hits distribution of sub-detectors(2)
Ecal reconstruction objects
Event count distributions of reco particles R > 20 GeV Particle direction (galactic coordinate) AMS position (geographic coordinate)
Proton spectrum: first try
Measurement schema data exposure time &event selection: selection reco spetrum data selection efficiency: reco spectrum unfolding incident spectrum geometry factor proton spectrum
Event selection proton trigger path particle reconstruction selection bit2 || bit5 ( FTC+Anti || FTC+FTE ) particle reconstruction selection 1 particle with track beta>0 && charge=1 track selection event.ntrk=1 layer8 && layer9 nhitY>=5 && nhitXY>=4 NoMSchi2 < 3.565+0.309*ln(R) nTofCluster=4
Geomagnetic cut and livetime cutoff=1.2×15 ×cos4(thetaM) adjust according to binning ignore events below cutoff reduce exposure time for rigidity below cutoff Live time Exposure time
Preliminary Spectrum Selected Events Proton Event rate Momentum distribution Proton Event rate Futher works includes efficiency, geometry factor, and unfolding
Thanks