W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker grounding & shielding of the CMS Tracker R. Hammarstrom (CERN EP/CMT) & W. Karpinski (RWTH AC I)

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Outline Overview of the CMS Tracker and its Readout electronics Grounding and shielding policy Cables and manifolds Grounding schema of TOB Grounding schema of TEC Tracker shielding

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker L ~ 5,4 meters Outer Barrel Inner Barrel Endcap Pixel  ~ 2,4 meters Tracker Overview

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Si – ModuleSi – Module Biasing 500V, I = 1.0 mA (after irrad.)Biasing 500V, I = 1.0 mA (after irrad.) Front endFront end based on APV25 chips based on APV25 chips supply voltage: supply voltage: +2.5 V ; 0V I= 90 mA +2.5 V ; 0V I= 90 mA +1.25V ; 0V I= 80 mA +1.25V ; 0V I= 80 mA Optical hybridOptical hybrid supply voltage: supply voltage: +2.5 V ; 0V I =300 mA +2.5 V ; 0V I =300 mA Control systemControl system based on DOH and CCU based on DOH and CCU supply voltage: +2.5 V ; 0V supply voltage: +2.5 V ; 0V CCU I =300 mA CCU I =300 mA DOH I =300 mA DOH I =300 mA

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Power supplies –Situated in counting room –PS modules power groups of ~60APV =10A, =4A =14A =10A, =4A voltage drop = 5V voltage drop = 5V Cables 3 major sectionsCables 3 major sections Patch Panel 3 (PP3) in USC55 – PP2 on balconies ~100mPatch Panel 3 (PP3) in USC55 – PP2 on balconies ~100m PP2– PP1 on HCAL ~40mPP2– PP1 on HCAL ~40m PP1 - module groups ~2m-5mPP1 - module groups ~2m-5m

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Overall grounding and shielding strategy Floating LV, HV power supplies of each detector group, their Return Lines connected inside the detector to the Common Inter-Detector Ground Shielded power cables with low D.C. resistance and a low impedance Shielded twisted pair cables for monitoring Electrical isolation from other systems -Data transmission, clock and trigger distribution per optical link -Galvanic separation of tracker interior manifolds,as close as possible to the detector, from the long distribution manifold outside the TK Detector located inside a faraday cage

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker All subdetectors All shields, All manifolds will be electrically connected to the 2 TK cylinder brackets A perfect and solid GROUND

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Interconnection and Grounding of the cables the individual shields remain insulated and interconnected at all three PP Shields grounded at the common detector ground and floating at PP3

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Cable inside the Tracker

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Cable PP1 to PP2

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Control Cable

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Prototype of the cable PP3 to PP2 Cable PP3 to PP2 Low impedance cable, Z ~2 Ohm -low inductance -high capacitance  -high immunity from E.M.I -minimize voltage overshoots due to current variations

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Galvanic insulation, as close as possible to Tracker All manifolds will be connected to Tracker brackets

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Grounding of TOB

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker TOB Ladder 6 silicon detector modules 6 front end hybrids 6 optocal hybrids 1 CCUM 1 Interconnect bus 1 Interconnect Card Ladder is powered over one power cable one floating LV channel two HV bias channels

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker -The cooling pipes are used as Local Ladder Ground to which LV and HV supplies are referenced. -The CCUM Ground is connected to the TOB Local Ladder Ground inside each Ladder Grounding of TOB Local Ladder Ground

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Grounding of TOB

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Grounding of TOB - The Manifold pipes (Ø 8.0 mm) are used as part of the „TOB Common Ground“, to which all corresponding LV and HV supplies are referenced. - The Digital Control (CCUM + DOHM) power supply and Control Cable Shielding are automatically connected to the TOB Common Ground

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Ground loops between Digital Control Cable and manifolds should be investigated Grounding of TOB

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Grounding of TOB  manifolds are inter connected electrically in radial manner  no loops inside the magnetic field and then tied to the TK brackets

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Grounding of TEC

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker TEC: Services of 1/8 of the end cap

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker 28 Si-detectors 28 FE hybrids 28 Opto hybrids 2 CCUM 4 IC Boards

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker The Si- modules on each petal are organized into three power groups with one multiservice cable serving each group LV and HV supplies of all three group are referenced to the Local Petal Ground, which is distributed along the interconnect boards as a reference stub The shields of the cables associated with the petal are tied to the Local Petal Ground Grounding schema of TEC- Petals

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Grounding schema of one Power Group The Local Petal Ground is insulated from the cooling system and petal CFK structure The detector frames are insulated from the cooling system. The CCUM Ground is not connected to the Local Petal Ground inside petals

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Local Petal Grounds of all petals of one control link (3) are connected to the TEC Common Ground The Digital Control (CCUM + DOHM) power supply and Control Cable Shielding are connected only once to the TEC Common Ground to avoid ground loops Grounding of the Control Link

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker End cap insulation disk TEC Common Ground could be realized using a thin Cu wire (  2mm, R=  /m) running in parallel in z direction or eventually cooling pipes (  12mm, R=  /m) The Cu wires and all manifolds of one half of TEC will be connected (elec) together at the end flange and tied to the 2 TK cylinder "brackets" at 3 and 9 o'clock positions

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker Shielding Tracker Support tube and the tracker end flange covered by 100 µm AL foil Shields tied to TK brackets No individual shielding of TOB Shielding of TEC under discussion - inner support tube, front and back terminating plates covered by 50 µm Al-foils - outer cylindrical skin made of metalized CFC or metalized kapton

W. Karpinski, Nov CMS Electronics week CMS Microstrip Tracker TK Shielding