Preshower Commissioning 2012 David Barney et al Commissioning

Preshower Commissioning 2012 David Barney et al Commissioning Runs: High Gain MIP calibration Silicon sensor High Voltage scan New ES HV System Re-plugged silicon sensors Latency revisited With many thanks in particular to: S-W. Li, C-M. Kuo, A. Honma, A. Peisert, R-S. Lu, P. Vichoudis, P. Petit, PP. Trapani, O. Holme, D. di Calafiori, S. Zelepoukin, P. Aspell, W. Bialas, K. Kloukinas, T. Tabarelli

Commissioning Runs - Calibration • Absolute calibration of the ES is with MIPs (Minimum Ionizing Particles) – Normal physics data-taking is in “Low Gain” mode (front-end configuration) with high dynamic range but low S/N ratio (~3) for MIPs – High Gain mode has limited dynamic range but good S/N ratio for MIPs (>10) • Use high quality tracks reconstructed in the Tracker to predict which ES strips are hit etc. • Need around 10 pb-1 of collision data with ES in HG and Tracker “on” – Accumulated 8. 8 pb-1 in LHC Fill 2482, runs 190591, 190592, 190593, 190595 – Data look fine for this purpose – Analysis will be done by Syue-Wei Li (“Poter”) in NTU Taiwan starting next week ES Commissioning 2012, ECAL DPG April 12 th 2 David Barney, CERN

Commissioning Runs – HV scan • ES contains sensors with a wide range of full depletion voltages (Vfd) – 384 individual High Voltage channels, with 384 different HV settings! • Vfd should decrease with radiation • Scan over a wide range of voltage to determine Vfd after ~6 fb-1 by looking at MIP distributions – Small amounts of data necessary as high accuracy not required Vfd at commissioning time (2010) ES Commissioning 2012, ECAL DPG April 12 th 3 David Barney, CERN

Commissioning Runs – HV scan (cont. ) • Scan between 20 V and 200 V in steps of 10 V, 10 minutes datataking for each point – During runs 190456, 190459, 190465, 190490, 190491 and 190492 – In the shadow of the TK/Pix HV scans – ES was in local DCS control • Simple setting of the HV via the CAEN mainframe – very fast and easy • Unfortunately, Global DAQ interpreted the lack of ES in Global DCS as meaning “HV off; set high threshold in ES-DCC” No MIP data! • Need to redo ES HV scan later in the year (at same time as next TK/Pix HV scan) – Determined only ~1 minute data needed for each HV setting ~half an hour needed in total – Will put ES in local DCS and make the scan after run started, to avoid problem of automatic setting ES Commissioning 2012, ECAL DPG April 12 th 4 David Barney, CERN

ES HV System 2012 • 81 sensors disconnected from HV system (and masked in data-taking) during 2010/2011 due to anomalously high surface currents (Internal Note submitted) observed with low levels of radiation (tens of pb-1) Mechanism producing high currents not fully understood Some indications that the surface currents can be “cured” with higher levels of radiation with sensors biased – e. g. one pair of sensors biased separately in late 2011 (not in data taking) reached asymptotic limit and then current decreased even during fills! ES Commissioning 2012, ECAL DPG April 12 th 5 David Barney, CERN

ES HV System 2012 (cont. ) – Total 384 HV channels (was 192 previously), supplying 2216 HV “lines” down to the detector via a patch-panel – New patch-panel includes active monitoring of current of each HV line (through ELMBs – as used for ECAL environmental monitoring etc. ) – Allows powering of “unplugged” sensors on dedicated HV channels for fine-grain control and monitoring ES+F(2) 6 lines unplugged 8 lines unplugged, 1 short 20 15 18 17 16 15 10 9 8 7 3 2 0 1 2 3 5 6 7 8 12 13 21 22 23 19 14 13 12 11 6 5 4 1 0 4 9 10 11 14 16 17 18 19 G 08 G 06 G 04 G 17 G 15 G 14 43 43 17 17 23 23 44 44 18 18 49 49 23 49 49 24 24 41 41 15 15 50 50 23 23 49 24 24 50 50 21 21 42 42 16 16 47 47 24 24 50 50 49 49 21 21 47 47 22 22 40 40 14 14 48 48 21 21 47 47 23 23 50 50 22 22 48 48 20 20 37 37 11 11 46 46 22 22 48 48 24 24 17 47 47 17 17 46 46 17 17 38 38 12 12 43 43 20 20 43 43 21 21 43 18 18 48 48 18 18 43 43 18 18 35 35 9 9 44 44 17 17 44 44 22 22 44 44 43 15 15 43 43 15 15 44 44 15 15 36 36 10 10 41 41 18 18 41 41 17 17 41 41 17 44 44 16 16 41 41 16 16 34 34 8 8 5 5 34 34 8 8 42 42 15 15 42 42 18 18 41 41 11 11 41 41 14 14 42 42 11 11 31 31 5 5 6 6 31 31 5 5 37 37 16 16 40 40 15 15 37 37 15 15 42 42 12 12 42 42 11 11 40 40 12 12 32 32 6 6 3 3 32 32 6 6 38 38 14 14 37 37 16 16 38 38 16 16 11 37 37 9 9 37 37 12 12 37 37 9 9 29 29 3 3 4 4 29 29 3 3 35 35 11 11 38 38 11 11 35 35 11 11 37 12 38 38 10 10 38 38 9 9 38 38 10 10 30 30 4 4 36 36 12 12 35 35 12 12 36 36 12 12 38 9 9 35 35 8 8 35 35 10 10 35 35 5 5 28 2 31 31 9 9 36 36 9 9 34 34 9 9 35 35 10 10 36 36 5 5 36 36 8 8 36 36 6 6 32 32 10 10 34 34 10 10 31 31 10 10 36 36 5 5 31 31 6 6 31 31 5 5 31 31 3 29 5 5 31 31 5 5 32 32 5 5 31 31 6 6 32 32 3 3 32 32 6 6 32 32 4 30 6 6 32 32 6 6 29 29 6 6 32 32 3 3 29 29 4 4 29 29 3 3 29 29 G 13 G 11 G 10 G 09 3 3 29 29 3 3 30 30 3 3 29 29 4 4 30 30 2 2 30 30 4 4 30 30 4 4 30 30 4 4 28 28 4 4 30 30 4 4 G 29 G 30 G 31 G 33 30 30 4 4 30 30 2 2 30 30 4 4 29 29 3 3 30 30 3 3 29 29 4 4 29 29 3 3 32 32 6 6 29 29 6 6 32 32 6 6 30 4 32 32 6 6 32 32 3 3 32 32 6 6 31 31 5 5 32 32 5 5 31 31 5 5 29 3 31 31 5 5 31 31 6 6 31 31 5 5 36 36 10 10 31 31 10 10 34 34 10 10 32 32 6 6 36 36 8 8 36 36 5 5 36 36 10 10 35 35 9 9 34 34 9 9 36 36 9 9 31 31 2 28 5 5 35 35 10 10 35 35 8 8 35 35 9 9 38 12 12 36 36 12 12 35 35 12 12 36 36 4 4 30 30 10 10 38 38 9 9 38 38 10 10 38 38 12 37 11 11 35 35 11 11 38 38 11 11 35 35 3 3 29 29 4 4 3 3 29 29 9 9 37 37 12 12 37 37 9 9 37 37 11 16 16 38 38 16 16 37 37 14 14 38 38 6 6 32 32 3 3 6 6 32 32 12 12 40 40 11 11 42 42 12 12 42 42 15 15 37 37 15 15 40 40 16 16 37 37 5 5 31 31 6 6 5 5 31 31 11 11 42 42 14 14 41 41 11 11 41 41 18 18 42 42 15 15 42 42 8 8 34 34 5 5 8 8 34 34 16 16 41 41 16 16 44 44 17 41 41 17 17 41 41 18 18 41 41 10 10 36 36 15 15 44 44 15 15 43 43 15 15 43 44 44 22 22 44 44 17 17 44 44 9 9 35 35 18 18 43 43 18 18 48 48 18 18 43 21 21 43 43 20 20 43 43 12 12 38 38 17 17 46 46 17 17 47 47 17 24 24 48 48 22 22 46 46 11 11 37 37 20 20 48 48 22 22 50 50 23 23 47 47 21 21 48 48 14 14 40 40 22 22 47 47 21 21 49 49 50 50 24 24 47 47 16 16 42 42 21 21 50 50 24 24 49 23 23 50 50 15 15 41 41 24 24 49 49 23 49 49 18 18 44 44 23 23 G 24 G 26 G 28 17 17 43 43 G 34 G 35 G 37 23 22 21 19 18 17 16 11 10 9 8 4 3 2 0 1 4 5 6 7 11 12 13 14 19 20 21 22 23 23 22 21 20 14 12 9 lines unplugged 7 6 5 15 0 1 13 20 2 3 8 9 10 15 16 17 18 0 lines unplugged One plane of ES sensors now has 96 HV channels (was 48 in 2011) - shown in the diagram by the different coloured blocks of sensors - “hatched” squares show sensors that were previously unplugged New HV patch-panel provides on-line monitoring of current of individual currents from each sensor pair – can react quickly to problems if they occur ES Commissioning 2012, ECAL DPG April 12 th 6 David Barney, CERN

ES HV System 2012 (cont. ) m. A • All 81 sensors “re-plugged” in March 2012 & included in DAQ Re-plugged sensors HV Channel Currents: Measured vs Expected “normal” sensors LV problems ES Commissioning 2012, ECAL DPG April 12 th m. A 7 David Barney, CERN

ES HV System 2012 (cont. ) • Re-plugged sensors show I increases correlated to L (expected) – – Can be controlled by lowering applied voltage Can monitor individual HV lines to chart progression Majority of problematic sensors already approaching an asymptotic limit Will increase HV to nominal value when sensors “cured” From CMSWBM: 1 HV channel, supplying 2 HV lines HV lowered by 75 V ES Commissioning 2012, ECAL DPG April 12 th From CMSONLINE “Generic Plotter”: ELMB measurements show sharing of current & asymptotic behaviour 8 David Barney, CERN

Latency Revisited • CMS Tracker front-end (APV chip) can store voltage samples from maximum 10 L 1 As – Off-detector “APV Emulator (APVe)” with direct connection to GT throttles the trigger before the APV memory is filled • ES front-end “PACE” chip can currently store max 13 L 1 As – Could occur very often (>1 Hz - see next slide) – But should never reach this limit as should be protected by APVe – In theory could increase latency by ~9 clocks to have the same capabilities as Tracker – Need to test to see if ES really is protected by APVe ES Commissioning 2012, ECAL DPG April 12 th 9 David Barney, CERN

New ES Latency Simulation ES Commissioning 2012, ECAL DPG April 12 th 10 David Barney, CERN

Latency Revisited (cont. ) • ES front-end “K-chip” has a very simple emulation of the PACE – Programmable register to set maximum number of L 1 As that can be stored in the PACE – If more triggers arrive, they are not sent to the PACE and “null events” are transmitted to the off-detector readout (ES-DCC) – Tested successfully: • Register set to a low value, closely-spaced triggers sent to front-end • Null events seen in ES-DCC (seen through event dump) – Implementing temporary counter in ES-DCC to count the number of null events received • Should be ready by the MD/TS • Plan to test in high-rate global running with Tracker – Set K-chip register to 10 L 1 As: should not see any null events (protected by APVe) – Set K-chip register to low value: should see null events at predictable rate ES Commissioning 2012, ECAL DPG April 12 th 11 David Barney, CERN

Backup ES Commissioning 2012, ECAL DPG April 12 th 12 David Barney, CERN

New ES HV Patch-panel From plies up HV s To detector “ELMB” mezzanines for measuring currents of each HV “line” ES Commissioning 2012, ECAL DPG April 12 th 13 David Barney, CERN