1 GAS S Bianco Colafranceschi Benussi Piccolo 2

1. GAS S. Bianco Colafranceschi Benussi Piccolo, … 2. SENSORS 4 UPGRADE S. Bianco S. Buontempo Caponero Breglio…, … Stefano Bianco per CMS Frascati s. bianco (frascati) CMS RPC Italia 12 maggio 1

GAS 1. Gas review al cern sull’incident della rottura del flussimetro SF 6 (0. 30% --> 0. 39%) piuttosto produttiva: https: //indico. cern. ch/conference. Display. py? conf. Id=137611 e minute di Pigi s. bianco (frascati) CMS RPC Italia 12 maggio 2

SF 6 Mass Flow Controller – follow-up 15/4 possible problem concerning the RPC gas mixture composition reported the SF 6 mass flow controller (MFC). MFC changed (19: 30) and to start preparing the gas chromatograph (GC). 17/4 17: 00 after discussion with RPC group, I put back the old MFC Analyses results: the old MFC is delivering about 30% more SF 6 with respect the new. SF 6 C 2 H 2 F 4 i. C 4 H 10 s. bianco (frascati) CMS RPC Italia 12 maggio 3

SF 6 Mass Flow Controller 18/4 20: 00 New MFC again in use 19/4 New analysis confirmed the 34% difference between the two MFCs (i. e. 0. 4 % instead of 0. 3 % of SF 6 in the mixture). 20/4 21: 50 SF 6 concentration in the return mixture from the detector: 0. 325% old MFC verified on the our Bronkhorst calibration stand: 35% difference in the output flow confirmed. 21/4 12: 00 SF 6 concentration in the return mixture from the detector: 0. 323% 21: 00 SF 6 concentration in the return mixture from the detector: 0. 322% 25/4 21: 00 SF 6 concentration in the return mixture from the detector: 0. 314% 3/5 Old MFC reinstalled after recalibration 21: 00 SF 6 concentration in the return mixture from the detector: 0. 312% Regular analysis (1 -2 per week Beatrice) will be performed until when the CMS GC will be fully operational s. bianco (frascati) CMS RPC Italia 12 maggio 4

GGM on wrong mix problem The GGM HV scan confirms shift of WP due to wrong mix In progress analysis of charge ratios timeline to spot (wrong. Mix->good. Mix) transition which should have occurred delayed in clean and (after/before) gas mixtures. A small transient effect possible. s. bianco (frascati) CMS RPC Italia 12 maggio 5

PRELIMINARY GGM down : -(((( APRIL 2011 s. bianco (frascati) CMS RPC Italia 12 maggio 0. 30%-->0. 39% SF 6 0. 39%-->0. 30% SF 6 +-10% HV scans 6

0. 30%-->0. 39% SF 6 0. 39%-->0. 30% SF 6 0. 30%-->0. 39% SF 6 s. bianco (frascati) CMS RPC Italia 12 maggio 7

ADC s. bianco (frascati) CMS RPC Italia 12 maggio 8

ADC s. bianco (frascati) CMS RPC Italia 12 maggio 9

CONCLUSIONS 0/3 1. 2. Il gas group effettuera’ misure di GC con il sistema CMS in USC 1/2 volte a settimana (Beatrice) Il GC INFN verra’ installato in SGX 5 e operato da RPC s. bianco (frascati) CMS RPC Italia 12 maggio 10

CONCLUSIONS 1/3 • GGM : – Stable operation, performance up to specs. • INFN GC : – Install and operate in SGX 5 gas room – Issues: automatize & integrate DCS/PVSS – runs : ~2 days frequency s. bianco (frascati) CMS RPC Italia 12 maggio 11

CONCLUSIONS 2/3 • The GGM is not designed for detecting overall gas mixture changes • Studies in progress to verify the feasibility of detecting gas mixture changes via the transient in the charge ratios. Small effects. • We propose to widen the scope and performance of GGM in order to provide an additional mean of monitoring for the RPC gas mixture • GGM+ : – HV feedback. Change HV supply to gaps as a function of p and T. Monitor charge and ratios • • PVSS changes including PVSS integration… 0. 5 month Unix data analysis… 1. 5 month Commissioning and debugging……. . 0. 75 month Value added: Gain experience for a CMS RPC feedback – HV scans. Every 10 days • • PVSS changes … 0. 5 month Auto scan tool C++/ROOT … 2. 0 months XDAQ changes… 0. 5 month Commissioning and debugging 0. 5 month • Need 6. 5 months support for a Frascati engineer (R. Aurilio or C. Vendittozzi). s. bianco (frascati) CMS RPC Italia 12 maggio 12

CONCLUSIONS 3/3 1. Abbiamo trovato e capito alcuni GGM analysis bugs 2. Il transiente si vede 3. A Frascati stiamo facendo HVSCAN con twin GGM • SF 6 = 0. 30/0. 39/0. 33/0. 30/0. 25 • Circa altri 10 giorni 4. A CERN abbiamo iniziato serie di HV scan con GGM per studiare sistematica e alternative al fit con la sigmoide s. bianco (frascati) CMS RPC Italia 12 maggio 13

TASKS & RICHIESTE 1. Install INFN GC and operate in SGX 5 • 1 mese … Beatrice (PV) oppure Vendittozzi (Frascati) 2. GGM+ • 6. 5 mesi … Vendittozzi (Frascati) o Aurilio (Frascati) o ? ? ? Altra risorsa RPC (Pakistan/India etc) s. bianco (frascati) CMS RPC Italia 12 maggio 14

POSSIBILE RIORGANIZZAZIONE GAS • GAS () 1. 2. 3. 4. Gas quality …. GC () Gas calibration …. GGM (Frascati) Liason to gas group (Benussi) Detector (leak tests + ? ? ? ) () s. bianco (frascati) CMS RPC Italia 12 maggio 15

SENSORS 4 RPC Frascati + Napoli • Installare sensori ottici FBG per temperatura camere endcaps nuove +esistenti • 2013 ma vogliamo iniziare a comprare, certificare, saldare sensori al polipo ASAP • Oggi distribuito primo draft di specifiche tecniche gara • Next: riunioni frascati/napoli • Lab Frascati pronto per test accettazione, Napoli anche disponibile s. bianco (frascati) CMS RPC Italia 12 maggio 16

SPARE SLIDES s. bianco (frascati) CMS RPC Italia 12 maggio 17

RPC GAS MONITORING 1. Gas Gain Monitoring (GGM) • Monitoring of working point for changes due to differences among clean, afterpurifiers, before-purifiers gas mixtures. Monitoring of charge ratios (after. Purifiers/clean, before. Purifiers/clean) allows cancellation of p, T, H effects 2. Gas Quality Monitoring • Monitoring of chemical composition of gas mixtures s. bianco (frascati) CMS RPC Italia 12 maggio 18

RPC GAS SYSTEM AND MONITORING Gas quality monitoring Purifiers GC+others (half wheel pickup points) Mixer Gas gain monitoring Humidifier CMS UXC 55 USC 55 GC Fp. H other SGX 5 s. bianco (frascati) CMS RPC Italia 12 maggio RPCs #1 Fresh gas DAQ Performance detector RPCs #2 monitoring Before purifiers ENV. CONTROL RPCs #3 gas parameters After purifiers Ambient parameters 19 19

GGM • Eight single gap RPCs with charge readout in a cosmics telescope • Three sets of gaps: clean gas, beforepurifier gas, after-purifier gas. Cancellation of p, T by ratioing. • fully integrated in DCS/PVSS • In operation and shift monitoring since 2009 https: //twiki. cern. ch/twiki/bin/view/CMS/RPComm s. bianco (frascati) CMS RPC Italia 12 maggio 20

GGM s. bianco (frascati) CMS RPC Italia 12 maggio 21

GGM s. bianco (frascati) CMS RPC Italia 12 maggio 22

Gas Gain Monitoring Performance Avalanche Streamer Anode charge in avalanche-streamer transition region monitors shifts in working point. SENSITIVITY ~ 20 V 0% SF 6 +-3%rms Coherent effects cancel out due to system redundancy. The two-gap ratio cancels out 0. 3% SF 6 s. bianco (frascati) CMS RPC Italia 12 maggio LONG-TERM ENVIRONMENTAL EFFECTS AT THE +-3% LEVEL 23

GGM on PVSS s. bianco (frascati) CMS RPC Italia 12 maggio 24

GGM TWIN IN FRASCATI CMS LAB T, H controlled hut Gaschromatograph DAQ system s. bianco (frascati) CMS RPC Italia 12 maggio +-1% +-0. 5 C 25

GAS QUALITY MONITORING • Gaschromatograph (GC) with columns optimized for RPC gas mixture components • Purchased in ~2007 by the INFN group and used by CERN gas group so far • Nicely complement to the CMS GC presently operated by the CERN gas group in USC. s. bianco (frascati) CMS RPC Italia 12 maggio 26

STATUS OF GGM AND GAS QUALITY • GGM • Fully integrated in DCS/PVS • In operation and shift monitoring since 2009 https: //twiki. cern. ch/twiki/bin/view/CMS/RPComm • Stable operation • Loss of efficiency in 1 gap, to be replaced • The GGM is performing up to specs • INFN Gaschromatograph • Not periodically used • No procedures for shifter use available yet s. bianco (frascati) CMS RPC Italia 12 maggio 27

OUTLOOK & GGM+ We propose actions to improve the monitoring of CMS RPC gas mixture: 1. Review of alarms on gas parameters (see G. Polese’s talk) 2. Integrate in the gas monitoring the INFN GC located at SGX 5 gas room. 3. GGM+ • p, T correction via HV feedback • HV scans s. bianco (frascati) CMS RPC Italia 12 maggio 28

GGM HV feedback test with twin system in Frascati With p, T correction on HV Without p, T correction on HV s. bianco (frascati) CMS RPC Italia 12 maggio 29

TYPICAL GGM HV SCAN s. bianco (frascati) CMS RPC Italia 12 maggio 30

GGM preliminary results on wrong mix problem April 29 th, 2011 - March 3 rd, 2011 Good mix Wrong mix s. bianco (frascati) CMS RPC Italia 12 maggio April 29 th, 2011 - January 2010 Good mix 31

RESOURCES 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. M. Abbrescia et al. , Gas analysis and monitoring systems for the RPC detector of CMS at the LHC, 
[physics/0701014] LNF-06 -34 -P (Jan 2007) 9 p. Presented by S. Bianco at the IEEE 2006, S. Diego (USA). M. Abbrescia et al. , The gas monitoring system for the resistive plate chamber detector of the CMS experiment at LHC. 
 2008. 4 pp. 
 18 th Hadron Collider Physics Symposium 2007 (HCP 2007) 20 -26 May 2007, La Biodola, Isola d'Elba, Italy. 
Published in Nucl. Phys. Proc. Suppl. 177 -178: 293 -296, 2008. CMS Collaboration, The CMS experiment at the CERN LHC, 2008 JINST 3 508004. L. Benussi et al. , Sensitivity and environmental response of the CMS RPC gas gain monitoring system, 
JINST 4: P 08006, 2009, . [ar. Xiv: 0812. 1710] L. Benussi et al. , The CMS RPC gas gain monitoring system: An Overview and preliminary results. 
Nucl. Instrum. Meth. A 602: 805 -808, 2009, . [ar. Xiv: 0812. 11]. L. Benussi et al, Sensitivity and environmental response of the CMS RPC gas gain monitoring system, LNF-08 -27(P), JINST 4: P 08006, 2009. 
e-Print: ar. Xiv: 0812. 1710. S. Bianco et al. , Chemical study of the CMS RPC closed loop gas system, CMS note 2010 - 007 L. Benussi et al. , Study of gas purifiers for the CMS RPC detector. 
[ar. Xiv: 1012. 5511] (Dec 2010) L. Benussi et al. , A New approach in modeling the response of RPC detectors. 
[ar. Xiv: 1012. 5508] (Dec 2010) 13 p. S. Colafranceschi et al. , Operational experience of the gas gain monitoring system of the CMS RPC muon detectors. 
Nucl. Instrum. Meth. A 617: 146 -147, 2010, . L. Benussi et al. , A new approach in modeling the response of RPC detector, presented by S. Colafranceschi at RPC 10, Darmstadt, to appear on NIM (2011) G. Saviano (for the CMS RPC Collaboration) Results on chemical analysis in the CMS RPC closed loop, presented at RPC 2010, Darmstadt (Germany). To appear on NIM (2011). https: //twiki. cern. ch/twiki/bin/view/CMS/RPComm https: //twiki. cern. ch/twiki/bin/view/CMS/Muon. Rpc. Private s. bianco (frascati) CMS RPC Italia 12 maggio 32

SPARES s. bianco (frascati) CMS RPC Italia 12 maggio 33

GGM-related studies on purifiers • • • Study of RPC purifiers at the scaleddown closed loop system located in the ISR area Release of contaminants in gas is correlated to currents increase Results available at 1. 2. 3. S. Bianco et al. , Chemical study of the CMS RPC closed loop gas system, CMS note 2010 - 007 L. Benussi et al. , Study of gas purifiers for the CMS RPC detector. 
[ar. Xiv: 1012. 5511] (Dec 2010) G. Saviano (for the CMS RPC Collaboration) Results on chemical analysis in the CMS RPC closed loop, presented at RPC 2010, Darmstadt (Germany). To appear on NIM (2011). • Currently running, expect run ending in about 2 months, move test to GIF s. bianco (frascati) CMS RPC Italia 12 maggio 34