A two dimensional multi-wire proportional chamber with delay line readout was developed,which has a large sensitive area of 30 cm×30 cm.Two cathode planes using printed circuit boards are orthogonally placed to give two coordinates of the impact point of the particle.Signals collected from the cathode strips are amplified and discriminated from two ends of the delay line at each cathode board.By recording the time difference between the two discrimination pulses and the common gate pulse from anode wires,a coordinate position was reconstructed,and a position resolution of better than 1 mm could be obtained in the whole sensitive area along the anode wires.
A high dynamic range readout system,consisting of a multi-dynode readout PMT and a VA32 chip,is presented.An LED system is set up to calibrate the relative gains between the dynodes,and the ADC counts per MIPs from dynode 7 are determined under cosmic-ray calibration.A dynamic range from 0.5 MIPs to 1×10 5 MIPs is achieved.
The magnetic characteristics of R5610A-01 photomultiplier tubes are studied in this paper.The experimental data shows that the gain of R5610A-01 loses about 53%when the magnetic field is 3 Gs along its+X axis.A cylinder of one-layer permalloy strip is able to reduce the effect of a 3 Gs magnetic field on the PMT gain to less than 1%.
A software system has been developed for the DArk Matter Particle Explorer(DAMPE) mission, a satellite-based experiment. The DAMPE software is mainly written in C++ and steered using a Python script. This article presents an overview of the DAMPE offline software, including the major architecture design and specific implementation for simulation, calibration and reconstruction. The whole system has been successfully applied to DAMPE data analysis. Some results obtained using the system, from simulation and beam test experiments, are presented.
The DArk Matter Particle Explorer is an orbital indirect dark matter search experiment which measures the spectra of photons,electrons and positrons originating from deep space.The electromagnetic calorimeter(ECAL),made of bismuth germinate(BGO),is one of the key sub-detectors of DAMPE,and is designed for energy measurement with a large dynamic range from 5 GeV to 10 TeV.In this paper,methods for energy correction are discussed,in order to reconstruct the primary energy of the incident electrons.Different methods are chosen for the appropriate energy ranges.The correction results of Geant4 simulation and beam test data(at CERN) are presented.
The temperature dependence of BGO coupled with photomultiplier tube R5610A-01 was studied in the range of-30–30℃. The temperature coefficient of the BGO and R5610 A as a whole was tested to be-1.82%/℃. And the temperature coefficient of the gain of the R5610 A is-0.44%/℃ which was tested in the same situation using a blue LED. Thus the temperature coefficient of BGO's light yield can be evaluated as-1.38%/℃.
The particle acceptance instead of the G-factors has been introduced for a particle telescope.The particle acceptance of a telescope module TEST is simulated by using the GEANT4 Monte-Carlo package.The results are presented and explained.
