1. Low Voltage Workshop, CMS Electronics Week CERN, 8 June 2010 W. Lustermann, ETH Zurich EB + EE LV systemOPFC MonitoringEB HV systemEE HV system

2. CMS Electronics WEEK, CERN, 7-11 June, 2010 2W. Lustermann, ETH-Zurich OPFC Maraton 4(3) Trigger Tower 4 x 15 A (5V) 4(3) Trigger Tower 4 x 15 A (5V) 4(3) Super crystals 4(3) x 15 A (5V) 4(3) Super crystals 4(3) x 15 A (5V) MEM box 2A (8V) + 5A (6V) MEM box 2A (8V) + 5A (6V) 220 V 15 A (AC) 380 V 10 A (DC) Control interface: - Maraton: CAN bus - OPFC: Monitoring in preparation Control interface: - Maraton: CAN bus - OPFC: Monitoring in preparation EB 3 OPFC + 3 Maraton per SM Total: 108 OPFC + 108 Maratons EE 7 OPFC + 7 Maratons / Dee Total: 28 OPFC + 28 Maratons

3. CMS Electronics WEEK, CERN, 7-11 June, 2010 3W. Lustermann, ETH-Zurich 4 failures (detected by blinking front-panel LED. OPFCs were replaced preventively. 12 spares in Bat. 904 and 3 in USC Repair: ~2 month OPFC no failures 7 spares in Bat904 3 spare (1 SM) in USC Repair: ~1 month MARATON

4. CMS Electronics WEEK, CERN, 7-11 June, 2010 4W. Lustermann, ETH-Zurich No leaks or other issues Flow rate is permanently monitored Controlled by ECAL Safety System (ESS) As soon as one channel is below threshold crates are shut down and interlocked MARATON water cooling Test in test stand Bat. 904 Send for repair via CERN Pool Re-test in Bat. 904 Records: logbook, private database (A. Singovski) Maintenance

5. CMS Electronics WEEK, CERN, 7-11 June, 2010 5W. Lustermann, ETH-Zurich Siemens PLC based system Developed by Belgrade Software (P. Milenovic, ETH) to be migrated to CMS tracker people Hardware (ETH Zurich), CERN PLC stock On call service: DCS expert ESS University of Minnesota Expert on Call LV system

6. CMS Electronics WEEK, CERN, 7-11 June, 2010 6W. Lustermann, ETH-Zurich OPFC monitoring hardware ready and 90% installed at P5. Keithly switch with USB-serial interface and PC, presently installed in the test setup Bat. 14 Software development: OPC sever plus PVSS/Framework component ongoing. (Oliver Holme, ETH Zurich)  ready by end of July Move to P5 at completion of the software remaining 10% of the system to point 5 and start to use it. Current plan: ready by end of Summer.

7. CMS Electronics WEEK, CERN, 7-11 June, 2010 7W. Lustermann, ETH-Zurich EB uses CAEN custom HV modules housed in SY1527 crates, providing up to 500V, 15 mA with about 20 mV of precision, using remote sensing over 120 m. Modularity 34 channels per super- module 1224 channels in total 18 crates for EB 8 modules per crate 9 channels per module Maintenance / Service Repair via CERN contract Expert on call (INFN Rome) Regular recalibration of the voltage precision (time consuming: 3x2 weeks / year) – INFN Rome Spare parts in HV Lab in Bat.15 and at P5

8. CMS Electronics WEEK, CERN, 7-11 June, 2010 8W. Lustermann, ETH-Zurich ~5 channels broken Typical individual channel (sometimes only the fuse) Sometimes the carrier board (module) Sometime the SY1527 crate supply or the 48 V board supply Total: 6 boards + ~35 channels per year Associated cost: 8k Euros per year Power cuts Similar to power cuts If announced: power down the crates Power glitches Not existing should improve the situation (3kW / crate) UPS Replacement of CPUs: (10 – 20) % per year SY1527

9. CMS Electronics WEEK, CERN, 7-11 June, 2010 9W. Lustermann, ETH-Zurich 2 CAEN SY1527 crates with 2 A1735P HV boards (Vmax = 1500V)RAL HV distribution system (custom crates with input, output and controller cards)8 crates per Dee each serving 156 channels Status: - No problems/issues with the CAEN system - issues with the robustness of the controller – input card setup (power glitches ??) - solved temporarily - new cards controller + input cards to be installed in December 2010 Status: - No problems/issues with the CAEN system - issues with the robustness of the controller – input card setup (power glitches ??) - solved temporarily - new cards controller + input cards to be installed in December 2010 Service / Spares - repairs: RAL - expert on call (permanently at CERN) - spares: more than 50% for all items Service / Spares - repairs: RAL - expert on call (permanently at CERN) - spares: more than 50% for all items ESS ramps down EE HV on an interlock of the LV system