1. First results from GEM-based Calorimeter prototype for the Linear Collider A.White 4/28/03 (for J.Yu, J.Li, M.Sosebee, S.Habib, V.Kaushik)

2. Double GEM schematic From S.Bachmann et al. CERN-EP/2000-151

3. From CERN-open-2000-344, A. Sharma

4. Design for DHCAL using Triple GEM Ground to avoid cross-talk Embeded onboard readout

5. UTA GEM Prototype - Double GEM detector constructed using 10x10 cm 2 foils from CERN. - Single 1x2 cm 2 anode pad. - Charge preamp, then voltage amp. Used - Cosmic trigger, small counters, low rate! - Signal verification: no signal with (a) trigger counters displaced from anode pad, (b) air in GEM detector.

6. GEM test chamber ( J.Li, UTA )

7. UTA GEM-based Digital Calorimeter Prototype

8. Prototype under construction in UTA NanoFab Cleanroom

9. Anode pad layout 1x2 cm 2 pad

12. GEM Prototype with preamp/voltage amp

13. GEM prototype – trigger counters

14. Single cosmic event: upper = trigger, lower = preamp output UTA GEM Calorimeter prototype

15. Single cosmic event: upper = trigger, lower = preamp output UTA GEM Calorimeter prototype

16. GEM signal distribution with Landau fit

17. GEM/MIP signal size - Double GEM – apply 426V/stage -Ionization ~30 i.p./cm => 10 e - / MIP - GEM Gain. (G) - Charge preamp sensitivity 0.25  V/e - (G C ) - Voltage amp. X10 (G V ) - Output signal = C x G x G C x G V -Observe ~160mV signal (mean of Landau) - => G = 6400 ± 20%

18. From CERN GDD group GEM gains UTA prototype

19. Conclusions - Prototype GEM detector for digital calorimeter sensitive layer has been successfully constructed at UTA. - GEM gain ~6400 for 426V across foils. - Many noise reduction/grounding schemes studied. - Single channel studies so far – next step: extend to multi-pad anode on layered readout board.