Prototype Module Design And Simulation Of VLAST Silicon Tracker Detector

The observations to the universe indicate that dark matter and dark energy are the main compositions of the universe.Study on dark matter may lead a revolution in the fundamental physics theory.The Dark Matter Particle Explorer(DAMPE),a Chinese space satellite launched in 2015,have detected an electron-positon cosmic-ray spectrum break in 0.9TeV and spectrum bump in 1.4TeV which still need more con firmation.Research on gamma-ray play an important role in dark matter indirect detection.However,the gamma-ray detec-tion capability of DAMPE was limit by its size and design.Accordingly,the DAMPE collaboration proposed a new gamma-ray detector which has the capabilities of wide en-ergy range,high spatial resolution,high energy resolution and high detection efficiency on gamma-ray measurement.This detector was named Very Large Area gamma-ray Space Telescope(VLAST).Not only inheriting DAMPE's excellent energy resolution and particle identification capabilities,VLAST also strengthen the gamma-ray detection capabilities greatly.The ambition of VLAST is to having breakthroughs in detecting the gamma-ray line spectrum or other dark matter characteristic spectrum,and making achievements in gamma-ray astronomy theory.In the prototype phase,the VLAST consists of 4 sub-detectors,the anti-coincidence detector(ACD),the silicon-tungsten tracker(STK),the BGO calorimeter(BGO)and the neutron detector(NUD).From top to bottom is STK,BGO and NUD,and these three sub-detectors are surrounded by ACD.The STK can provide precise particle track information by position reconstruction.My work mainly contains two part.In the first part,the silicon micro-strip de-tector(SSD)ladder module for VLAST prototype was designed and tested.Front-end electronics was designed and data acquisition system for ladder module was developed.The second part is the simulation for VLAST SSD ladder module and STK proto-type.Based on the parametric model of the SSD ladder module,the sensor position res-olutions under different sensor and electronic parameters were simulated with Allpix2 toolkit.Next,the VLAST STK model was constructed based on SSD ladder module and its angular resolution was simulated and discussed.In chapter 1,dark matter detection and other frontier astrophysics topics are de-scribed.Then the scientific goals and prototype design of VLAST are introduced.The fundamental of particle detection and some silicon particle tracker in space experiments are introduced in chapter 2.Chapter 3 shows some signal analysis principles on SSD.The design and testing on VLAST STK ladder are introduced in chapter 4.The design contained the sensor hybrid assembly,data-acquisition(DAQ)system design and the console software development.We also tested the linear performance within the dynamic range,channel crosstalk,baseline level and RMS noise of VLAST SSD ladder module.Testing results indicated that VLAST SSD ladder sensor with 384 channels were successfully readout by DAQ system at 725e-equivalent noise charge(ENC).And the integral nonlinearity(INL)is better than 3%for most channels with in 0-200fC input charge range.Position resolution of VLAST SSD ladder module was simulated and discussed in chapter 5.In this chapter,the charge distribution characteristics of SSD were analyzed.Different sensor geometry and readout electronics parameters have different impacts on the module position resolution.The position resolution simulation was carried out with several parameters,such as sensor strip pitch,intermediate strip numbers,module signal-noise ratio,incident particle direction and readout ADC resolution.Simulation results suggested that SSD sensor with one floating strip between readout strips has better position resolution performance when readout pitch is fixed.In chapter 6,the STK prototype with 18-layer(36 sub-layers)SSD ladder module and thin tungsten foils was established.Based on the parametric simulation model in chapter 5,the relationship between STK angular resolution and inclined angle or energy of the incident gamma-ray was simulated.The results showed that the angular resolution for 50GeV vertical incident photon was better than 0.1°.