Calorimeter Status: Preparing RUN II Pascal Perret LPC Clermont 25 February 2014

2 ECAL LED monitoring system upgrade  Present system LED light is transported to PMTs through plastic optical fibers Fibers are exposed to significant radiation dose at the ECAL front face (max ~100 krad for one year (2 fb -1 )) Radiation degradation of clear fibers Pascal Perret - LPC Clermont 25/02/2014 − monitoring box Degradation rate can be estimated to ~ -15% for 7 krad

3 ECAL LED monitoring system upgrade  Replacement of the plastic fibers to rad hard quartz ones Core Ø 200 µm chosen Their diameter is smaller  Replacement of LED Present red Ligitek LUR3333H  blue: PMT QE will be increased by factor of ~10 Choose brightest available LED type The Multicomp “MegaBright Blue” LED was chosen ~1000 LED have been purchased and the 500 brightest ones have been selected; Measurement of the rad hardness of UCL, Louvain-la- Neuve*, June µm pure silica-high OH core from Polymicro and Fryazino (Russia). Transparency loss measured after short (20-30 min) annealing Both fibers are good enough Polymicro fibers ordered (30 km) Pascal Perret - LPC Clermont 25/02/2014 * This test was supported by AIDA: FP7 Research Infrastructures project AIDA, grant agreement no

4 ECAL LED monitoring system upgrade  Bundle production The new fiber will be plugged into the old optical connectors at the ECAL modules: 6500 plastic end pieces and nuts have ordered to UNIPLAST, Vladimir, Russia. Pascal Perret - LPC Clermont 25/02/2014 nut end piece module connection fiber

5 ECAL LED monitoring system upgrade  Bundle production The new fiber will be plugged into the old optical connectors at the ECAL modules: 6500 plastic end pieces and nuts have ordered to UNIPLAST, Vladimir, Russia. To adapt the end piece to quartz fiber, one has to insert into it a ceramic ferrule held in a brass tube 7000 ferrules ordered Brass tubes machined by ITEP Pascal Perret - LPC Clermont 25/02/2014 nut end piece module connection fiber Brass tubes (left); brass tubes + ferrules (right)

6 ECAL LED monitoring system upgrade  Bundle production LED end connector 500 plastic holders in white POM for the LED end were drilled 456 bundles produced in 6 months (mid September – mid February) Team of 3 persons from ITEP Pascal Perret - LPC Clermont 25/02/2014 LED end Module end

7 ECAL LED monitoring system upgrade  Bundle production (16 or 9 fibres/bundle) Cutting of the fibres at different legnths from 2m to 8m: 85 different sets 456 bundles 29.2 km Insertion into a thermo-shrinkable tube Pascal Perret - LPC Clermont 25/02/2014

8 ECAL LED monitoring system upgrade  Bundle production (16 or 9 fibres/bundle) Polishing the LED ends control with a microscope Gluing the module ends Pascal Perret - LPC Clermont 25/02/2014

9 ECAL LED monitoring system upgrade  Bundle production (16 or 9 fibres/bundle) Polishing the MODULE ends control with a microscope Gluing the LED end pieces Pascal Perret - LPC Clermont 25/02/2014

10 ECAL LED monitoring system upgrade  Bundle production (16 or 9 fibres/bundle) Quality control All the bundles are checked with LED pulses and PMT before gluing the LED end piece and after Pascal Perret - LPC Clermont 25/02/2014

11 ECAL LED monitoring system upgrade  Bundle installation mass production of bundles was finished mid-February except for gluing the black plastic end pieces (arriving from ITEP) Preparation: Test of the bundle layout: Outer zone Pascal Perret - LPC Clermont 25/02/2014

12 ECAL LED monitoring system upgrade  Bundle installation: Access thanks to RICH2 tower extension Pascal Perret - LPC Clermont 25/02/2014 Design: O. Jamet. Calculation: Joao

13 ECAL LED monitoring system upgrade  Bundle installation: Access thanks to RICH2 tower extension Pascal Perret - LPC Clermont 25/02/2014 Installation: Cédric, Tengiz  A load test was performed for 1 st level mid- January  RP visit: January 22 nd  VIC visit: January 23 rd  Use of platforms and step ladders to work all along the ECAL wall  Bundle installation started on January 27 th.

14 ECAL LED monitoring system upgrade  Bundle installation: Layout: The LEDs are installed inside monitoring boxes placed at the bottom (8) or top (2) of ECAL Pascal Perret - LPC Clermont 25/02/2014

15 ECAL LED monitoring system upgrade  Bundle installation: Installation sequence: first side A, from Inner to Outer: Box #s: 6,7,8,9,10 then side C: Box #s: 5, 4, 3, 2, 1. 1st step was to dismount the current bundles commissioning started after the installation of the first box (#7) Pascal Perret - LPC Clermont 25/02/2014

16 ECAL LED monitoring system upgrade  Bundle installation: the commissioning goes on in parallel reasonable amplitudes (~500 ADC counts in the centre at ULED=3.5V) few (Inner) cells to be fixed in boxes #6 and #7 ULEDs and TSB delays to be tuned side A to be finished by March 10 Then installation of side C after having move RICH2 tower extension … Should be completed by beginning of May Pascal Perret - LPC Clermont 25/02/2014

17 Detector maintenance  SPD intervention performed first week of July: 3 problematic SPD VFE 2 boards replaced 3 rd one ok: low occupancy due to ageing  increase HV  PS intervention will be performed tomorrow: 1 VFE board to change corresponding to PS7FEB06 LED system: a short on the detector for 1 LED board to fix Pascal Perret - LPC Clermont 25/02/ subchannels not working properly

18 Detector maintenance  Water leak A small water leak has been spotted by DSS in rack L3B01 on Dec. 20. A visual inspection seems to indicate it is coming from the horizontal heat exchanger inside the rack. The two valves at the top of the rack have been closed. Pascal Perret - LPC Clermont 25/02/2014 A (false) fire alarm triggered CO2 extinguisher in this rack some time before: correlations? Was changed To check that electronics was not damaged!

19 Detector maintenance Wiener PS and turbine maintenance: Dec. 12 – end of Jan. From L. Roy 11/02/14 LS1 meeting: Pascal Perret - LPC Clermont 25/02/2014 Cooling plant restarted, Air cooling units restarted everywhere, main switch boards repowered, all DSS alarms enabled for Calo. Still the CO2 bottle to exchange (Ecal last rack C side). Turbines: 1 unit seems not working in rack L3B02 Demineralized water filtered have been clean-up Sub- detector Power Supplies CAEN Power Supplies WIENER Air cooling Units (D3+B1) Air cooling Units (Detector side) CALO- come back Re-installed Re-installed cables to exchange Re-installed

20 Detector maintenance  HCAL No dead cells in the run, However: There are unstable PMTs (mainly rate effect) L0Calo level variations during fill Pascal Perret - LPC Clermont 25/02/2014 Significant positive rate effect in >10% of HCAL PMTs !!! Dark current in many PMTs (increasing with time, even shutdown) difficult 137 Cs calibration with too high dark current Presence of dark current >10 nA is highly correlated with presence of high rate effect (>5%) (however not 100% correlation). an example 139 PMTs have >5% 180 PMTs have >4% ref t0 Nov 2012

21 Detector maintenance  HCAL: towards understanding the problem Pascal Perret - LPC Clermont 25/02/2014 Significant sensitivity degradation in 2012 for many PMTs with high rate effect (apart from high occupancy area). No similar effect/significant sensitivity degradation observed in ECAL Why??? Loss of vacuum? Test in He

22 Detector maintenance  HCAL: the goal equip the very central part (highest occupancy) with perfect PMTs, to stabilize the L0Calo; replace the worst PMTs in the rest of HCAL select a good batch of bad PMTs, in order to (try to) ask (HAMAMATSU) experts to help us in understanding the problem For HCAL C: (~same expected for the A side) 109 PMT replacements; criteria for replacement were arbitrarily set depending on I DARK OR rate effect according to PMT location. Some dismounted PMTs were re-used for replacements at periphery (49) 60 PMTs removed and replaced by new ones. Pascal Perret - LPC Clermont 25/02/2014 HCAL-PMT-C

23 Detector maintenance  CALO moving system Software of the system being improved Help to diagnose why it is not working (e.g. wrong connections) Lead: closure to be improved Pascal Perret - LPC Clermont 25/02/2014 Seems to be difficult to re-align … Attempt to grind the edges … XCAL rails & vis à billes to clean up, to grease, etc.

24 Detector maintenance  CALO moving system ECAL A-side moving system damaged To be changed SPD moving system could also be damaged … Access more tricky! Pascal Perret - LPC Clermont 25/02/2014

25 LS1 Activities: summary To come: HCAL A-side, ECAL A&C side To be scheduled CALO moving system maintenance XCAL maintenance: few days per side at latest as possible to fix possible new problems … Pascal Perret - LPC Clermont 25/02/2014 Feb 3March 3 April 7 ECAL LED A-side HCAL C-side HCAL A-side PS C-side Lead RICH2MUON ECAL C-side ECAL LED C-side ECAL A-side PS, Turbines, etc.

26 Calibration  We had a workshop on Oct. 9th: Summary provided by Marie-Noelle at 2nd LHCb Computing workshop on Nov. 7th Calibration will be based on occupancy method Reference depends upon the magnetic field Need 80Hz of minimum biais event to calculate occupancy cell by cell Analyse events only in mu stable condition The PMT HV can be updated when the deviation > 2-sigma of its resolution This method was used in November 2012 to update ECAL HV It will remove the ageing dependence from trigger Possible to check the agreement with LED measurement It has to be completed by fine calibration (FMDST) A lot of work is needed: We have to progress on the automation of the calibration! New people from Annecy are joining Pascal Perret - LPC Clermont 25/02/2014

27 Feb/May Feb/Nov Calibration  Initial calibration will have to be done in 2015: Not well known calibration due to annealing... From LED: Pascal Perret - LPC Clermont 25/02/2014 The annealing from fiber important and still goes on (~4% May- November) The annealing from PMT (scintillators) smoother(2%)

28 Summary & Conclusion Pascal Perret - LPC Clermont 25/02/2014  A lot of work during LS1 Installation and commissioning of a new ECAL LED monitoring system Progressing smoothly! Detector maintenance SPD, HCAL C-side done PS this week, ECAL, HCAL the following weeks Try to understand HCAL PMT issue Purchasing of additional PMT will be needed Moving system Change of the part of system (ECAL A-side) to schedule Addition of TELL1 (a new rack in D3) to be scheduled Calibration New scheme and automation under preparation

29 SPARES Pascal Perret - LPC Clermont 25/02/2014

30 HCAL PMTs  Towards understanding the problem: One PMT (large dark current, conductivity between anode and a dynode) was opened: no conductivity between pins over the bulb surface; large (and unstable) conductivity over the dynode support (the substance used by HAMAMATSU to treat seems to be hygroscopic). the dark current may be a consequence of loss of vacuum (?) Supported by different design of the HCAL PMT/CW – unlike in ECAL, mechanical tension to PMT pins may occur (a hard spacer between PMT and PCB)  micro cracks in glass. Not the case for ECAL. If this is the case, practical consequences: we can expect further degradation of HCAL PMTs, and replace ~100 every winter shutdown for new PMTs, the HCAL PMT/CW design should be revised to exclude mechanical tension. Further studies: a He test proposed (V. Rykalin) – compare life time of a good and a bad PMT in He. Pascal Perret - LPC Clermont 25/02/2014

31 Calibration  An alternative ageing measurement has been developed by Irina: it is based on raw occupancy Method (as a reminder): Pascal Perret - LPC Clermont 25/02/2014 Precision reached with 1 hour data taking

32 Pascal Perret - LPC Clermont 25/02/2014 Procedure for Module end ( for every fiber in a bundle): glue the fiber into the connector polish with the polishing machine control with a digital microscope, polish again if necessary Procedure for LED end (all the 16 (9) fibers): Glue all fibers together into a brass tube 1.25 mm inner diameter; polish with a polishing machine, controlling with a digital microscope; Glue the tube into the Plexiglas holder, together with a piece of 1.2 mm clear- PSM fiber (for PIN diode control). Module end connector (single fiber) Production procedure for 200 μm fibers LED end connector (16 or 9 fibers) is simpler: gluing and polishing instead of stripping and cutting by a cleaver (thin 10 µm coating is essential).