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Progress of GEM R&D in Lanzhou University Hui-Yin Wu( ) Outline Time properties of GEM-detector signal Position correction R&D of GEM-DAQ Future plan Jul. 27, 2017 Progress of GEM R&D in LZU 2

Time properties of GEM-detector signal A typical GEM detector: Cathode; Drift region; GEM foils; Induction region; Readout PCB Point of incidence Cathode Center of gravity + + + + ++ ++ +

+ ++ Point of incidence + ++ + + Work Gas + Readout PCB XX Jul. 27, 2017 Progress of GEM R&D in LZU

3 Time properties of GEM-detector signal The velocity of Alpha (~7mm/ns) is much larger than the drift velocity of electron(~0.05mm/ns) Jul. 27, 2017 Progress of GEM R&D in LZU 4 Position correction 45 100um thick FR4 can completely block Alpha particle.

Alpha particle can incident at 45 at most. Cathode is made of a 2um Aluminized Mylar foil reducing to block Alpha particle energy. Jul. 27, 2017 Progress of GEM R&D in LZU 5 Position correction APV25 chip with 25ns sample period Slit

Strip readout with pitch of 600 um Detector THGEM foil: a thickness of 200 um, pitch of 600 um, a hole diameter of 200 um, and a rim of 80 um Jul. 27, 2017 Progress of GEM R&D in LZU 6 Position correction A typical Alpha signal with 6 samples(maximum number of samples

MPD) The center of gravity shift to the right along with time increase. Jul. 27, 2017 Progress of GEM R&D in LZU 7 Position correction 6th sample 5th sample 4th sample

+ 3rd sample 2nd sample + + + 1st sample L1/L2=S1/S2=A + + L1

Similar triangle problem S1 L2 S2 Jul. 27, 2017 Progress of GEM R&D in LZU 8 Position correction Y=a*X+ b

(1) Each event go through (p, t) t=a*p + b (2) a and b represent the linear fitting parameters for each track. Jul. 27, 2017 Progress of GEM R&D in LZU 9 Position correction Linear Fit gravity center of first three samples for each track

and get the parameters a and b Jul. 27, 2017 Progress of GEM R&D in LZU 10 Position correction Channel=b-x*a a and b are linear fitting parameters for each track x=-15.36.3 Before correction 2056 137.28

Jul. 27, 2017 FWHM MAIN Progress of GEM R&D in LZU 645 137.40 After correction 11 R&D of GEM-DAQ

Connect to Readout PCB: 140P signal + 18P Ground Connect to APV25 Ground 4 layers PCB with 2 Ground layers Connect to APV25 signal input Jul. 27, 2017 Progress of GEM R&D in LZU 12 R&D of GEM-DAQ Jul. 27, 2017

Progress of GEM R&D in LZU 13 R&D of GEM-DAQ New DAQ Unit Control Output HDMI A 19Pins Ethernet Port Signal Input HDMI A19Pins FPGA: Xilinx-V5 One unit can control 16 APV25 chips, total 2048 Channels. 30 samples per event

Trigger Input LED Jul. 27, 2017 Progress of GEM R&D in LZU 14 R&D of GEM-DAQ New backplane 4 Apv25 chips per backplane New DAQ

HDMI A 1 Jul. 27, 2017 2 Progress of GEM R&D in LZU 3 4 15 Future plan Develop the new DAQ system

Try to correct position in FPGA chip(online) Jul. 27, 2017 Progress of GEM R&D in LZU 16 Thank you for your attention Jul. 27, 2017 Progress of GEM R&D in LZU 17