ATL-IC-ES-0011 - new version available - approval starts Grounding of the ID subsystems Jan Kaplon ATL-IC-ES-0011 - new version available - approval starts 11/17/2018

ID GND – connection to ATLAS GND Two connection points on ATLS support structure: IDGNDPA and IDGNDPC Exact location to be confirmed by George Blanchot 11/17/2018

Connection to ATLAS GND system Two connection points: IDGNDPA and IDGNDPC on side A and C respectively 11/17/2018

Grounding principles Subdetectors are electrically independent (floating power supplies) except the IDGND connections All connections to the IDGND from subdetectors are from EM shields (TE) analogue and digital gnd referenced on the detector modules module ground connected to the individual EM shield Routing of ground cables – sector 13A/tile finger gap 51*A and sector 13C/tile finger 51C * Updated in ATL IC ES 0011 recently (to copy with engineering drawings and inventory) 11/17/2018

Pixel detector – connection to IDGND Single point connection to IDGND of PST EM shield at PP1 11/17/2018

SCT – connection to IDGND Cable connected on the heat spreader plate (barrel) Break at ppf1 (EC) 11/17/2018

TRT – connection to IDGND 8 AWG grounding cable is available - ask for sample 11/17/2018

Barrel cable trays and conical plate barrel cable trays are connected to IDGND ring (electrical isolation from support structure sitting on LArg) conical plate elements and trays connected using cable bridges engineering drawing ATLICSPF 0035 11/17/2018

Barrel cable trays and conical plate GND connection of IDGND ring (conical ring) in region of tile finger gap 51A and 51C cable trays connected by conical plates serve as an extra shield for pipes coming to barrel SCT and TRT (electrical breaks on ppb1) 11/17/2018

Routing of the grounding cables 11/17/2018

Grounding of the ID end plate Electrical continuity up to Tile structure – connected to overall ATLAS GND Check the possibility of the RF ground (Litz wires or solid bond connections) of IDEP cover plate to IDGNDPA and IDGNDPC or ATLAS support structure (recent request by N. Spencer) 11/17/2018

Cooling and gas pipes Inside EMI shields of a given subdetectors: grounding of the tubes provided by the sub-detector grounding schemes (electrical breaks before EM shields) Outside the sub-detector systems grounded at platform isolation from barrel cable trays (trays + conical plate connected to IDGND) TRT : kapton isolation for cooling, peek pipe for gas SCT: pipes in thermal isolation (electrical isolation) isolation from End Cap cable trays (trays are part of EM shields) TRT : peek pipes SCT cooling: wrapped by kapton sheet Support structures on LArg ()  isolated from LArg, electrical continuity to Tile structures (ATLAS GND) 11/17/2018

Cooling and gas pipes Details of PPB1 showing grounding of the pipes, location of the electrical break, and the reference point. Detailed grounding scheme of the TRT services. 11/17/2018

Barrel cable tray – isolation techniques Trays connected to conical plate and to IDGND 11/17/2018

EC cable tray – isolation techniques TRT: trays part of the TRT EM shields SCT: trays connected to relevant EM shields on ppf1 TRT and SCT EC cable trays need to be isolated – This includes also the PPF1 boxes (to be checked) Pipes have an electrical breaks before EM shields – need to be isolated 11/17/2018

EC cable tray – isolation techniques 11/17/2018

48V heaters 48V – PP1 connected to SCT base plate (barrel SCT ground) TRT heaters – the same scheme (2 particular SCT base plate connected to TRT ground (to be checked) ) 11/17/2018

110V heaters 110V heaters: grounded on power pack side +-55V cable shield (LEMO connector) bonded to the cooling pipe (heater body and pipe – electrical continuity to ATLAS GND) 11/17/2018

DCS items Readout by ELMB – isolated signal ground for ADC DCS items referenced by cable shields on given SCT PP1 Separate ELMB for the items referenced to different EM shields 11/17/2018

Aluminium-copper connection Tinned Copper Terminal and Jumper Structure Screw or bolt and nut plate Lock-nut Washer A Washer B Washer C Aluminum Alloy Stainless Steel Cadmium Plated Stainless Steel Stainless Steel or Cadmium Plated Stainless Steel Aluminum1 Alloy None 1.Use washers having a conductive finished treated to prevent corrosion (Alodine) Extracted from AC 43.13-1B document (could be found on http://atlas-id-grounding.web.cern.ch/ATLAS-ID-Grounding/ ) 11/17/2018