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)

Double GEM schematic

From S.Bachmann et al. CERN-EP/2000-151

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

Design for DHCAL using Triple GEM

Ground to avoid cross-talk

Embeded onboard readout

UTA GEM Prototype

- Double GEM detector constructed using 10x10 cm2 foils from CERN.

- Single 1x2 cm2 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.

GEM test chamber ( J.Li, UTA )

UTA GEM-based Digital Calorimeter Prototype

Prototype under construction in UTA NanoFab Cleanroom

Anode pad

layout

1x2 cm2 pad

GEM Prototype with preamp/voltage amp

GEM prototype – trigger counters

Single cosmic event: upper = trigger,

lower = preamp output

UTA GEM Calorimeter prototype

Single cosmic event: upper = trigger,

lower = preamp output

UTA GEM Calorimeter prototype

GEM signal distribution with Landau fit

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- (GC)

- Voltage amp. X10 (GV)

- Output signal = C x G x GC x GV

-Observe ~160mV signal (mean of Landau)

- => G = 6400 ± 20%

From CERN GDD group

GEM gains

UTA prototype

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.