1. Phase 2 R&D – Brief Introduction –
GE2/1
Phase 2 R&D – Brief Introduction –
Marcus Hohlmann
Florida Institute of Technology
Paolo Vitulo
Università di Pavia & INFN Pavia
GEM Workshop XV, CERN, July 21, 2016

2. Phase 2 R&D, GEM workshop XV, CERN
Where are we now?
GE2/1
GE2/1
Triple-GEM baseline:
We pretty much have a consensus on basic geometry
20-degree chamber made from 4 trapezoidal modules
Full-size mechanical mock-up of sector constructed
Mechanical details of modules being worked out
We are converging on the conceptual layout of the readout board (partitioning; number of OH’s)
µRWELL option:
First large prototype (GE1/1-size) currently under construction
Michele’s talk
Luigi’s talk
7/21/2016
Phase 2 R&D, GEM workshop XV, CERN

3. Phase 2 R&D, GEM workshop XV, CERN
Where are we now?
ME0
Triple-GEM baseline:
Back-to-back design option underwent first beam test with small prototype; promising first results
Have recognized the need to revisit discharges in GEM
Not an issue in GE1/1, but in ME0 rates much higher
Investigating how to measure discharge rate induced by hips
Neutron irradiation
New α-tests on lab bench (opportunity for an offsite group)
FTM option:
3 small prototypes developed and tested so far
Timing measurement in 2015 beam test (~ 2 ns res.)
Latest prototype being revamped
Paolo’s talk
Ilaria’s talk
7/21/2016
Phase 2 R&D, GEM workshop XV, CERN

4. Phase 2 R&D, GEM workshop XV, CERN
GE2/1 R&D Schedule I
GE2/1
Triple-GEM
Baseline
7/21/2016
Phase 2 R&D, GEM workshop XV, CERN

5. Phase 2 R&D, GEM workshop XV, CERN
GE2/1 R&D Schedule II
GE2/1
7/21/2016
Phase 2 R&D, GEM workshop XV, CERN

6. Phase 2 R&D, GEM workshop XV, CERN
ME0 R&D Schedule I
7/21/2016
Phase 2 R&D, GEM workshop XV, CERN

7. Phase 2 R&D, GEM workshop XV, CERN
ME0 R&D Schedule II
7/21/2016
Phase 2 R&D, GEM workshop XV, CERN

8. Phase 2 R&D, GEM workshop XV, CERN
Thank you!
7/21/2016
Phase 2 R&D, GEM workshop XV, CERN

9. Phase 2 R&D, GEM workshop XV, CERN
BACKUP
7/21/2016
Phase 2 R&D, GEM workshop XV, CERN

10. Discharge test with Triple-GEMs
Accumulation of 450 discharges over a few cm2.
However, conditions quite different from those in CMS.
Observations:
Discharges are non-destructive
No impact on gain
Thin deposition of copper oxide in the irradiated region (all GEM foils)
Superficial copper etching near the rim of the holes
These do not affect the detector operation
In CMS, for ME0 we expect ~1.5 × 10-5 discharges s-1 cm-2, or ~ 5 × 10-5 discharges per second over a few cm2, or one discharge every ~2 × 104 seconds over a few cm2.
=> The test corresponds roughly to 9 × 106 s of running in CMS, i.e. 15% of the total expected up-time of 6 × 107 s of the HL-LHC over 10 years.
Caveat: There are large uncertainties in these estimates!
Conclusion: Promising, but need to revisit estimates and do more tests to reach 10 HL-LHC equiv. years. If this indeed poses a problem, investigate mitigation.
Charge 6

11. Performance - big picture
ME0
GE2/1
RE3-4/1
Performance
Parameter
Baseline
requirement
Additional requirement
(option)
3-GEM
FTM
µRWELL
Std. RPC
iRPC
MRPC
Rate
capability
2 kHz
n/a ok
90 kHz (SF3)
Trigger
time resolution
< 8ns
< 2ns no
< 100 ps
maybe
Bending angle
Δφ with CSCs
φ resolution
< 0.3mrad
Reconstruction
spatial
resolution
≈ 400 µm
0.8 – 1.7 mm
Operation
eco-friendly gas
7/21/2016
Phase 2 R&D, GEM workshop XV, CERN