1. Technische Universität München
GEM-TPC Meeting
Bernhard Ketzer
Technische Universität München
03 March 2009
GSI

2. Agenda Communications (B. Ketzer)
Status of TPC FE and readout electronics (I. Konorov)
Status of GEM-TPC prototype (B. Voss)
Pad plane design (M. Berger)
TPC calibration concepts (A. Winnebeck)
a.o.b.

3. ELSA Beam Test

4. ELSA Beam Test Achievements:
All detectors installed: trigger scint., 4 Si planes, 4 GEM planes, TPC
Slow control for HV and LV
Readout electronics and DAQ:
FE DB, DATE, S-Link
1 EVB, 1 ROB, 1 HotGeSiCA (Si/GEM), 2 HotGeSiCA (TPC)
TCS + trigger module
Decoding & online monitoring
Commissioning of beam telescope
Noise: ~ 700 e- (Si), ~ 1400 e- (GEM)
Latencies adjusted fo GEM/Si
Efficiency scans for GEM
TPC tests
Drift field stable up to 400 V/cm, GEM HV up to 106% of nominal
16 T2K chips read out (one by one), noise ~900 e-

5. Noise in the Laboratory

6. Noise at ELSA

7. ELSA Beam Test Problems: Readout FE DB configuration error
Synchronization problem for GEM detectors
No remote power cycle for ADCs
Only 256 samples could be read for TPC
2nd HotGeSiCA (TPC) did not send data
S-Link readout errors when TPC is read together with other equipment
Silicon pedestal file not written
Slow Control
Web interface for HV/LV too slow and not intuitive to use
No online gas flow monitoring for GEM/TPC
Gas analysis not operational
Pressure gauge not available      
being improved

8. ELSA Beam Test Items to be addressed:
Analysis of beam telescope performance
Track reconstruction
Alignment
Residuals, Efficiencies
TPC latch all data
understand pulse height spectra
correlations with trigger?
TPC readout
understand problems with latch readout
understand timing (inject test pulse)
simultaneous latch readout of all chips
sparse readout
work in progress  
almost done
Goal:
Test sparse readout of TPC during present beam time at ELSA!
~ 3 days of beam as main user in March-April

9. T2K Chip Timing
Injection of a test pulse synchronized with the trigger
Sensitivity: 0.1 fC/ADC ch.
Timing: Latency between TCS trigger and pulse measured: 1ms
25 ms time gate (511 samples at 20 MHz)