To reduce the discharge of the standard bulk Micromegas and GEM detector, the GEM-Micromegas detector was developed at the Institute of High Energy Physics. Taking into account the advantages of the two detectors, one GEM foil was set as a preamplifier on the mesh of Micromegas in the structure and the GEM preamplification decreased the working voltage of Micromegas to reduce the effect of the discharge significantly. At the same gain, the spark probability of the GEM-Micromegas detector can be reduced to a factor 0.01 compared to the standard Micromegas detector, and even the higher gain could be obtained. In the paper, the performance of the detector in X-ray beam was studied at 1W2B Laboratory of Beijing Synchrotron Radiation Facility. Finally, the result of the energy resolution under various X-ray energies was given in different working gases. It indicates that the GEM-Micromegas detector has the energy response capability in the energy range from 6 keV to 20 keV and it could work better than the standard bulk-Micromegas.
Gas electron multiplier(GEM) detector is used in Cosmic Muon Scattering Tomography and neutron imaging in the last decade. In this work, a triple GEM device with an effective readout area of 10 cm × 10 cm is developed, and an experiment of discriminating between cosmic muon and x-ray based on rising time is tested. The energy resolution of GEM detector is tested by 55 Fe ray source to prove the GEM detector has a good performance. The analysis of the complete signal-cycles allows to get the rising time and pulse heights. The experiment result indicates that cosmic muon and x-ray can be discriminated with an appropriate rising time threshold.
The one-dimensional position sensitive wire gaseous detector is developed for the synchrotron radiation diffraction, which consists of a single wire of gold-plated tungsten and 200 cathode strips as the readout. The induced signal is produced by the several adjacent cathode strips when X-ray is incident on anode wire with high voltage. Using the center gravity method to analyze the adjacent signals in one dimension, the primary ionization position of the X-ray can be obtained and the position resolution is 160 μm (FWHM). In Beijing Synchrotron Radiation Facility, the diffraction test is done at the experimental station. When the X-ray irradiates the crystal sample of SiO2, the different sizes of the diffraction rings can be produced. The diffraction angles are measured to be 11.148° and 14.201°, and the two-dimensional diffraction rings are reconstructed when the detector is moved and scanned with the several steps in the diffraction ring range. The diffraction aberration of one-dimensional wire chamber is very obvious. In the paper, the relevant influence factors of the detector construct are discussed. The thickness of the working gas and the width of active area window can give rise to the diffraction ring aberration. The theoretical calculation value of the diffraction aberration is larger than the position resolution value of the gaseous detector. The correction method is established based on the corresponding physical analysis, and by this method the value of the diffraction ring point is calculated. The relative aberration of diffraction position is improved by up to 7% with using the method, and the two-dimensional diffraction ring with no aberration can be reconstructed.
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