19122021 J A Merlin On behalf of the
19/12/2021 J. A. Merlin On behalf of the CMS muon group 1
Channel loss rate = BKG rate * discharge prob. * propagation prob. * damage prob. Discharge Probability Propagation Probability Damage Probability Intrinsic to all gaseous technologies Low probability with triple-GEM (~10 -9 -10 -10) Understood the process of propagation in large detectors Mainly driven by the large capacitance of the foils Understood the process of damage in large detectors Mainly due to propagation re-ignitions It is a “no pain no gain” parameter Found 3 ways to mitigate discharge propagation: à Reduce foil capacitance à Increase filter resistance à Use drain resistors Found 2 ways to mitigate discharge propagation: à Improve electronics input protection à Increase the de-coupling with the filter capacitance 19/12/2021 J. A. Merlin On behalf of the CMS Muon Group 2
Damage probability of the VFAT 3 front-end electronics during propagating discharges at fixed energy 1 m. J/discharge (maximum energy expected in GE 1/1 detectors). The x axis represents the four configurations: baseline VFAT hybrid HV 3 b-V 2; VFAT hybrid HV 3 b-V 3 with external protection resistors 330 Ω; VFAT hybrid HV 3 b-V 3 with external protection resistors 470 Ω; VFAT hybrid HV 3 b. V 4 with external protection diodes. Note: edited version of an already approved plot. Here we only show 4 out of the 11 configurations shown in the approved plot. The format is the same. For approval 19/12/2021 J. A. Merlin On behalf of the CMS muon group 3
Comparison of the discharge propagation probability of triple-GEM detectors as a function of the induction electric field. The discharges are triggered in the third GEM foil by 5. 5 Me. V alphas particles in Ar/CO 2 (70/30%). The three curves represent three different configurations: 10 x 10 cm 2 triple GEM detector (black), GE 1/1 long detector with standard GEM foils (red), GE 1/1 long detector with doublesegmented GEM foils (blue). For approval 19/12/2021 Note: this is a combination of two plots already approved. The format is the same. J. A. Merlin On behalf of the CMS muon group 4
GE 1/1 Triple-GEM Detector CMS GEM Configuration Gas = Ar/CO 2 (70/30%) Rate capability of a GE 1/1 Long detector showing the relative gas gain in Ar/CO 2 (70/30%). The three curves represent three options of the filter resistance from 10 kΩ to 1 MΩ. The x axis represents the interaction rate normalized with the simulated interaction rate expected in the GE 1/1 disk at HL-LHC. Normalized Interaction Rate For confirmation 19/12/2021 J. A. Merlin On behalf of the CMS muon group 5
Discharge propagation probability of a 10 x 10 cm 2 triple-GEM detector as a function of the induction electric field. The discharges are triggered in the third GEM foil by 5. 5 Me. V alphas particles in Ar/CO 2 (70/30%). Modified 19/12/2021 J. A. Merlin On behalf of the CMS muon group 6
Discharge propagation probability of a GE 1/1 Long detector as a function of the induction electric field. The discharges are triggered in the third GEM foil by 5. 5 Me. V alphas particles in Ar/CO 2 (70/30%). Modified 19/12/2021 J. A. Merlin On behalf of the CMS muon group 7
Discharge propagation probability of a 10 x 10 cm 2 triple-GEM detector as a function of the resistance of the HV filter connected to the GEM 3 bottom electrode. The discharges are triggered in the third GEM foil by 5. 5 Me. V alphas particles in Ar/CO 2 (70/30%). Modified 19/12/2021 J. A. Merlin On behalf of the CMS muon group 8
Discharge propagation probability of a GE 1/1 Long detector as a function of the resistance of the HV filter connected to the GEM 3 bottom electrode. The discharges are triggered in the third GEM foil by 5. 5 Me. V alphas particles in Ar/CO 2 (70/30%). Modified 19/12/2021 J. A. Merlin On behalf of the CMS muon group 9
Discharge propagation probability of a 10 x 10 cm 2 triple-GEM detector as a function of the induction capacitance. The discharges are triggered in the third GEM foil by 5. 5 Me. V alphas particles in Ar/CO 2 (70/30%). Modified 19/12/2021 J. A. Merlin On behalf of the CMS muon group 10
Discharge propagation probability of a 10 x 10 cm 2 triple-GEM detector as a function of the third GEM foil capacitance. The discharges are triggered in the third GEM foil by 5. 5 Me. V alphas particles in Ar/CO 2 (70/30%). Modified 19/12/2021 J. A. Merlin On behalf of the CMS muon group 11
Discharge propagation probability of a 100 cm 2 triple-GEM detector as a function of the induction field for different values of drain resistors between the readout plane and the ground. The discharges are triggered in the third GEM foil by 5. 5 Me. V alphas particles in Ar/CO 2 (70/30%). Modified 19/12/2021 J. A. Merlin On behalf of the CMS muon group 12
Onset induction field of a 10 x 10 cm 2 triple-GEM detector as a function of the drain resistor between the readout plane and the ground. The onset field is defined as the induction field at which the discharge propagation probability is equal or greater than 1%. The discharges are triggered in the third GEM foil by 5. 5 Me. V alphas particles in Ar/CO 2 (70/30%). Modified 19/12/2021 J. A. Merlin On behalf of the CMS muon group 13
VFAT 3 damage probability in a 10 x 10 cm 2 triple-GEM detector as a function of discharge energy for the three different hybrid designs. The discharges are triggered in the third GEM foil by 5. 5 Me. V alphas particles in Ar/CO 2 (70/30%). Modified 19/12/2021 J. A. Merlin On behalf of the CMS muon group 14
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