a Stanford Linear Accelerator Center b CEA-Saclay, c LPNHE des Universités Paris 6 et Paris 7 d LAL, Universite Paris Sud e Ecole Polytechnique, Laboratorire Leprince Ringuet f Lawrence Berkeley National Laboratory g Colorado State University h University of Cincinnati i University of Tennessee D ETECTION OF I NTERNALLY R EFLECTED C HERENKOV LIGHT STATUS REPORT Kalanand Mishra, University of Cincinnati BaBar collaboration meeting - September 29 th 2005 The B A B AR -DIRC Collaboration R. Andreassen, h N. Arnaud, d D. Aston, a N. van Bakel, a D. Bernard, e D.N. Brown, f J. Chauveau, c X. Giroux, d Ph. Grenier, e G. Grosdidier, d T. Hadig, a G. Hamel de Monchenault, b A. Höcker, d M. John, c R.W. Kadel, f M. Legendre, b J. Libby, a A.-M. Lutz, d J. Malcles, c G. Mancinelli, h B.T. Meadows, h K. Mishra, h D. Muller, a J. Ocariz, c M. Pripstein, f B.N. Ratcliff, a S. Schrenk, e J. Schwiening, a M.D. Sokoloff, h S. Spanier, i K. Suzuki, a G. Therin, c Ch. Thiebaux, e G. Vasseur, b J. Va'vra, a R.J. Wilson, g G. Wormser, d A. Yarritu, a Q. Zeng, g M. Zito b

2 Overview  DIRC Safety  Data Quality  Fast Monitoring  Operations  DIRC Backgrounds  DIRC Water Quality  Spares Status  Shutdown Plans  Conclusion

3 DIRC Safety DIRC Safety documents available on the web at Additional safety requirements in light of the new Controlled Access guidelines. Modification of the routine worker JHAM to deal with this issue : List of subsystem workers allowed to make Controlled Access: 43 Arnaud Nicolas 44 Mishra Kalanand 45 McCulloch Matthew 46 Salvati Emmanuele 47 Va'vra Jaroslav All of them are trained now. DIRC Crew

4 Data Quality Run 5 data : good quality overall Re-processing of Runs 1-4 going smoothly - Problem with the new sector-by-sector rolling calibrations fixed - Monitoring improved to detect problems (similar to the ones mentioned below) quicker 4 hardware failures since the beginning of Run 5 : - broken fan (5/29)  30 min down time - failure of a HV board (7/10)  89 pb -1 bad data - broken chiller component (9/13)  45’ down time - FEE power supply failure (9/27)  DIRC out of data- taking for a day DIRC Crew

5 Fast Monitoring JAS pages more user-friendly. one plot per page with more precise explanations. improved layout : each page has links to the previous & next plots for easy navigation. Nicolas Arnaud DIRC Fast Monitoring ( 1/5) : Fast monitoring guidance improved :

6 Operations (1/5) May, 29: Fan failure ( 30’ DT) - Shut down FEE crate in sector 2 - Status bypassed, crate running with 8/9 fans - Replaced the fan tray during June access - Complete replacement scheduled (all sectors) in October shutdown to avoid similar problems in future Kalanand M Nicolas A Emmanuele S Healthy fan Dying fan Alarm Level

7 Operations (2/5) July, 10: For the first time ever, a HV board (in sector 1) died - Problem clearly visible in DQM plots. - Problem didn’t trigger red alarm but rather a permanent yellow alarm and scaler rate went ~ 0. Noticed after 3 hrs by pilot. - Board replaced 2 hrs later with help from Jose ( owl shift ; at least 2 people needed to safely replace a HV board) - 6 runs with ~ 3% DRC-acceptance off. Data declared unusable by DQG (89 pb -1 ). - redefined alarm levels to protect against such failures. Kalanand M Nicolas A Emmanuele S Occupancy in Sector 1 TDC hits per group

8 Operations (3/5) Sequence of events : -1:30 am: HV board 5, sec 1 fails - 4:36 am : DRC expert paged - 4:46 am : Problem understood, decided to replace the board - 6:06 am : beam-lost  inj./tune - 6:30 am : board replaced - 6:36 am : stable beam Lessons Learned: - Fast monitoring layout improved to 'force' DQMs to look at occupancy plots per HV group; - low alarm levels added for scalers; - similar failure would now trigger a red alarm in the alarm handler. Kalanand M Nicolas A Emmanuele S

9 Scaler rate, sector 3 7 am 8 am Page Switch to BCS Back to data taking Beam loss! Injection Chiller goes off Operations (4/5) Sept, 13: Chiller failure( 45’ DT) - one of the two stirrers failed. - hardware problem  switched to the Backup Chiller System immediately, HVAC investigated the problem later. - safe to run the chiller with one stirrer for few days, spares were ordered. - both the stirrers replaced on 09/22 during an MD, one spare kept in case of future failures. DIRC Crew

10 Operations (5/5) June, 20: Discovered and unplugged a Xmas tree in sec 1 during ROD. Two new Xmas trees found in sectors 5 (7/26) & 3 (9/12)  to be unplugged during shutdown. Xmas tree rate is NOT increasing ! DIRC Crew year X’ tree Sept, 27: Front-end power supply failure - Sector 9 FEE stopped communicating with epics - required detector access, unfortunately the hall crew needed to open the door was not available for 24 hours - DIRC taken out of data-taking in this period - problem in power supply (ps) identified and ps replaced Sept, 28: Niels (with help from Jim Hamilton) fixed problem with global calibration and implemented some useful new features for online monitoring.

11 DIRC Backgrounds DIRC background estimated by Jerry’s formulation New variables defined for monitoring: Scaler Value/ Expected Scaler Value Expected scaler rate is a linear function of I HER, I LER & luminosity Very high bkg in June-July associated with ‘low’ luminosity Significant improvement in August and September Background levels are now similar to what they were at the end of Run 4 (expected rates are conservative) Jerry V Nicolas A et al AprilMay June July August September luminosity Scalar ratio 1 1 1

12 Water transmission, resistivity and acidity stable PMT glass removal rate: 5  /yr << 1000  front glass thickness Low bacteria level For details see : DIRC Water Quality Jerry V

13 Spares status  Front End : OK  HV boards: OK  FEE Fans : see the next slide  We have dedicated web-pages to monitor spares Summary list of all spares: List of current boards used in the DIRC: List of all boards with internal and slac IDs:  A good situation overall Kalanand M Nicolas A Emmanuele S

14 Shutdown Plans (1/3) Shutdown schedule: doors opening on Mon 10/10 work could start on Tue 10/11 bridge in Wed 10/19 ( Curtain wall permitting ) bridge out Thu 10/27 doors closed Fri 11/10 Main Planned Activities: To change all the FEE fans in all sectors (see next slide) To plug out the two Xmas trees (in sectors 3 and 5) Test spare HV boards Two N 2 flow-meters to calibrate ( sectors 0 and 10 ) Fri 10/21 DIRC Crew

15 Replacement of fan trays: Shutdown Plans (2/3)  All fans in our FEE (total 108) to be changed.  Details already finalized in the October shutdown planning. FEE Fans are reaching their “expected lifetime”. 2 fan failures since last December. 3 out of 9 fans per sector cannot be bypassed via epics  A failure of any one of them would require opening the door ( ~ 2 shifts ). DIRC Crew

16 Replacement Schedule: - Fan trays from bottom sectors to be replaced first: 8 sectors reachable from ground / with ladders - Expected rate: up to 2 trays / day - Switch on a crate immediately after its fan replacement  to let the fans run as long as we can - When bridge is installed, 4 fan trays already replaced will be moved from bottom sectors to top ones - All fans will run for more than 2 weeks before doors are closed ! ( To remove any chance of infant mortality ) Shutdown Plans (3/3) DIRC Crew

17 Conclusion Safety procedure: in place. Fast monitoring: improved. Data Quality: OK. Operations: all problems encountered were fixed. Background studies: in progress. Shutdown plans: finalized. Manpower shortage during most of the year complicated the ops crew’s task. We expect the situation to improve soon and to be significantly better in Welcome Emmanuele and Rolf ! Kalanand M again !