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

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