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

2. 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

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

4. 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

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

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

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

8. 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

9. 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

10. Routing of the grounding cables
11/17/2018

11. 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

12. 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

13. 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

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

15. 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

16. EC cable tray – isolation techniques
11/17/2018

17. 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

18. 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

19. 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

20. 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 B document (could be found on )
11/17/2018