1. The Preliminary Test and Plans of GEM Detector in Tsinghua Rensheng Wang ( 王仁生 ) Tsinghua U. ( 清华大学 ) The Third Workshop on Haron Physics in China and Opportunities with 12GeV JLab Collaborators: Zhi-Gang Xiao, Zhao Zhang, Wei-Hua Yan, Han Yi, Ai-Xing Wang

2. Outline: Brief introduction to GEM detector The set up of test Some results of test Near future plans Summary

3. GEM at Tsinghua TPC read-out based on GEM ( See Talk by Yulan LI ) 16 channel CSA and shaping amplifier ( by Zhi Deng ) … … To start with a small GEM prototype, trying to study the energy resolution, space resolution and signal properties (like cluster size and broadening) varying with the high voltage, strip width and gas mixture. By comparing these measurements with the large prototype in the next step, we will know the effect of the large readout board size on the signal propagation.

4. Brief introduction to GEM detector -HV Drift /Sensitive (~1-3kv/cm) Transfer (~1-3kv/cm) Induction (~1-3kv/cm) Cathode GEM1 (300v-500v) GEM2 (300v-500v) Anode/Readout strip ~2-30 mm ~1-2mm ~1-6mm

5. The set up of test GEM foil (CERN): 50mm*50mm 300um 400um 100um 200um

6. The set up of test Operating conditions: 1,Atomosphere pressure ； 2,Active gases ： Ar&C o 2 : 75/25—90/10 Drift /Sensitive Transfer Induction Cathode GEM1 GEM2 Anode/Readout strip 2.625mm 2.25mm 1.625mm -HV( 1300V-1900V ) 1MΩ 13MΩ 20MΩ 22MΩ 20MΩ 16MΩ … Charge-Sensitive Preamplifier (16 channels) Main Amplifier ADC CFD DAQ Logical OR fout GG8020

7. The result of test This test includes two sections: 16 in 1 : 16 adjacent strips are connected to one input, to test: energy resolution, effective gain; 16 in 16 : 16 adjacent strips are connected individually with 16 preamplifiers input, to test:  Diagnose spectrum of signal;  the energy resolution;  the signal characters, such as the cluster size, high central moment … … … Charge Amplifier …

8. 16 in 1 … Charge Amplifier Fe55 Homemade

9. 16 in 1

10. Charge Amplifier … Fe55 16 in 16

12. Energy Resolution:

13. 16 in 16 Cluster size of signal of main peak - HV 17101710 17501750 Ar758085

14. 16 in 16 Therein: is the position of fired strip; is the amplitude of signal; is the position, calculated from centroid;

15. 16 in 16 Second central moment/Variance - HV 17101710 17501750 Ar758085

16. Near Future Plans  Further detailed test, such as :  Beam test at Jlab?  A prototype for SoLID Space resolution; VME DAQ ( 1024 channels-ordered ) ; Simulation; Timing performance; Proportionality of signal; … GEM Silicon strip Cosmic ray Source ~45cm ~48cm ~20cm

17. Summary  GEM-Detector prototype test has been started in Tsinghua;  The performance of the tested prototype is consistent with literature report : 1),energy resolution is about 20%-30% for Fe55 depending notably on read-out strip parameters, insignificantly on gas-mixture or HV; 2), 2 nd Moment of the signal distribution, increasing slightly with decreasing quenching gas, is larger for the 400um strip space configuration;  Next step is to build a prototype for SoLID;

18. Thanks ！