The Preliminary Test and Plans of GEM Detector in Tsinghua

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

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 Cathode ~2-30 mm Drift /Sensitive(~1-3kv/cm) GEM1(300v-500v) ~1-2mm Transfer(~1-3kv/cm) GEM2(300v-500v) ~1-6mm Induction(~1-3kv/cm) Anode/Readout strip

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

6. The set up of test -HV(1300V-1900V) Operating conditions: 1,Atomosphere pressure； 2,Active gases： Ar&Co2 : 75/25—90/10 1MΩ Cathode 13MΩ 2.625mm Drift /Sensitive 20MΩ 2.25mm 22MΩ Transfer 20MΩ 1.625mm GEM1 Induction 16MΩ GEM2 Main Amplifier Charge-Sensitive Preamplifier (16 channels) ADC … … DAQ Anode/Readout strip CFD GG8020 fout Logical OR

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 Charge Amplifier … …

8. 16 in 1 Fe55 … … … … Homemade Charge Amplifier

9. 16 in 1

10. 16 in 16 Fe55 … … Charge Amplifier … …

11. 16 in 16

12. 16 in 16 Energy Resolution:

13. 16 in 16 Cluster size of signal of main peak

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

16. Near Future Plans Cosmic ray Source Silicon strip • 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 ~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), 2nd 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！