To reduce the discharge of the standard bulk Micromegas and GEM detectors, a 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 significantly reduce the effect of the discharge. 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 an even higher gain could be obtained. This paper describes the performance of the X-ray beam detector that 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. This indicates that the GEM-Micromegas detector has an energy response capability in an energy range from 6 keV to 20 keV and it could work better than the standard bulk-Micromegas.
A one-dimensional single-wire chamber was developed to provide high position resolution for powder difraction experiments with synchrotron radiation.A difraction test using the sample of SiO2has been accomplished at 1W2B laboratory of Beijing Synchrotron Radiation Source.The data of the beam test were analyzed and some difraction angles were obtained.The experimental results were in good agreement with standard data from ICDD powder difraction file.The precision of difraction angles was 1% to 4.7%.Most of the relative errors between measured values of difraction angles and existing data were less than 1%.As for the detector,the best position resolution in the test was 138 μm(σ value) with an X-ray tube.Finally,discussions of the results were given.The major factor that afected the precision of measurement was deviation from the flat structure of the detector.The efect was analyzed and the conclusion was reached that it would be the optimal measurement scheme when the distance between the powder sample and detector was from 400 mm to 600 mm.
A new concept for a hybrid structure gaseous detector module with ion backflow suppression for the time projection chamber in a future circular collider is presented.It is a hybrid structure cascaded Gas Electron Multiplier(GEM) with a Micromegas detector.Both Micromegas and GEM have the capability to naturally reduce most of the ions produced in the amplification region.The GEM also acts as the preamplifer device and increases gas gain together with the Micromegas.Feasibility tests of the hybrid detector are performed using an ^(55)Fe X-ray source.The energy resolution is better than 27% for 5.9 keV X-rays.It is demonstrated that a backflow ratio better than 0.2% can be reached in the hybrid readout structure at a gain of 5000.
