Simulation of silicon strip detector for space-based cosmic ray experiments with Allpix^(2)

Purpose Silicon strip detectors are widely applied in space-based cosmic ray experiments and most of the silicon strip detectors deploy an analytical method for its digitization.However,the analytical method simplifies the physical process of propagation of electrons/holes generated inside the silicon detector by particles that pass through the detector.In order to simulate silicon strip detectors with different configurations comprehensively,the Allpix^(2),an open-source software,is used to study those processes.Methods When particle passes through the silicon detector,energy is deposited based on Geant4 simulation,and electron-hole pairs are created due to the deposited energy.The Allpix^(2)simulation method and the analytical method are both used to calculate or simulate the diffusion and drift processes that electron-hole pairs propagate inside the silicon detector under internal electric field,and the number of electrons/holes accumulated at implanted strips are counted.Results and conclusion The number of electrons/holes accumulated along the implanted strips are compared between the Allpix^(2)simulation method and analytical method for different incident angles and different incident positions,they are found to be in good agreement for proton particles,while there are discrepancies for carbon and silicon particles.The Allpix^(2)software may be an important tool for the study of response of silicon strip detectors in space.The charge resolution of single implanted strip predicted by Allpix^(2)simulation method is about 4.7%for proton,3.8%for carbon and 1.6%for silicon particles for an incident angle of 45◦.

Chapter 1 LHAASO Instruments and Detector technology

The Large High Altitude Air Shower Observatory(LHAASO)(Fig.1)is located at Mt.Haizi(4410 m a.s.l.,600 g/cm^(2),29°21'27.56"N,100°08'19.66"E)in Daocheng,Sichuan province,P.R.China.LHAASO consists of 1.3 km^(2) array(KM2A)of electromagnetic particle detectors(ED)and muon detectors(MD),a water Cherenkov detector array(WCDA)with a total active area of 78,000 m^(2),18 wide field-of-view air Cherenkov telescopes(WFCTA)and a newly proposed electron-neutron detector array(ENDA)covering 10,000 m^(2).Each detector is synchronized with all the other through a clock synchronization network based on the White Rabbit protocol.The observatory includes an IT center which comprises the data acquisition system and trigger system,the data analysis facility.In this Chapter,all the above-mentioned components of LHAASO as well as infrastructure are described.

100 TeV diffuse γ-rays observation by YangBaJing Hybrid Array

Purpose Cosmic rays up to PeV energy are believed to be generated in our galaxy.γ-rays at 100TeV energies are important probe to identify PeVtrons.Besides,γ-rays contain additional information on the propagation of the galactic cosmic rays.Methods Diffuseγ-rays originating from the Galactic plane from 20 to 200 TeV region are studied with early 160-day data collected by YangBaJing Hybrid Array(YBJ-HA),which is a hybrid array and consists of scintillation detectors and underground muon detectors.All-distance equi-zenith angle and time-swapping methods are used to analyze the number ofγ-rays excess.Result and conclusion Because of no significant observation onγ-ray emission,Helene's method is adopted to derive the 90%confidence level upper limits on the flux of diffuse galacticγ-rays.And the limit to the ratio of the flux ofγ-rays to CRs is obtained at the order of 10^(-4),which is the current best result at these energies.