Type-I Electrical Services Status and Plans

1. Type-I Electrical ServicesStatus and Plans Jason Nielsen Santa Cruz Institute for Particle Physics University of California, Santa Cruz U.S. ATLAS ITk Pixel Workshop September 6, 2019

2. Introduction • Type-I services are part of on-detector services activity • In international project: L3 activity coordinators are T. Flick, J. Nielsen • In US ATLAS project: L3 manager is M. Hance, IC is J. Nielsen • Other Type-I services contacts: S. Eisenhardt (EC), ?? + D. Alvarez (OB) • Scope is all electrical services running from PP0 to PP1 (except Env. Monitoring) • LV module power • HV sensor bias • LV MOPS (née DCS controller) power • CANbus DCS data • Temperature interlock • Low-power command line (to be discussed) • Electrical services follow SP chain via inner system PP0 U.S. ATLAS ITk Pixel Workshop-- 2019-09-06

3. Type-I Connector Baselines • At PP0 • Samtec UMPT power blades • carries LV in PP0 design • >12 A, > 1500 VDC • Samtec TLH/SLH strip (2mm) • Carries HV, DCS, Tilock in PP0 design • Sneaks underneath twinax bundle • Open to other options on PP0 • At PP1 • Petr Sicho’s studies of custom connector (Glenair) • We need to be able to crimp the 36 AWH solid HV wires and 16 AWG stranded LV wires at PP1 • Or we will need another cable termination board U.S. ATLAS ITk Pixel Workshop-- 2019-09-06

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6. Grounding & Shielding Considerations • Proposal to use CANbus shield as low-impedance tie between PP0 and PP1 • In other parts of the G&S document, “low transfer impedance” defined as 50 mΩ/meter, but that is a shielding performance quantity • DC impedance requirement is <10Ω • All we need is the spiral-wrap foil shield of the CANbus pair • Measured in our 3-m prototypes to have R<1Ω (includes drain wire helping connect wraps) U.S. ATLAS ITk Pixel Workshop-- 2019-09-06

7. Cable Specifications and Vendors • Bare copper requirement (vs. silver-plated) is a challenge for small-gauge wires • Low-voltage power: 16 AWG (7/24) or 18 AWG (7/26) TWP, thin PEEK • Product from Dacon for 250-μm PEEK wall • High-voltage sensor bias: 36 AWG solid TWP, quad-dipped Kapton (25-μm) • Stock from MWS, as for IBL. Mechanical stripper to remove insulation, tested to 3kV • I would like to know about the IBL experience and switch to 32 AWG for build • VMOPS, interlock: 32 AWG () TWP, thin PEEK • Product from New England Wire with 115-μm PEEK wall. Impedance uncontrolled for this TWP. • CANbus: 32 AWG () TWP, thin PEEK, Al/Kapton foil shield • Product from New England Wire with 300-μm PEEK wall, designed for 100-Ω impedance • No silver, no polyester -- whew! • Low-voltage cables all rated to 300 V, not 1000 V • Need six weeks for final delivery of materials U.S. ATLAS ITk Pixel Workshop-- 2019-09-06

8. Design of Termination Region • Prototype cable termination board designs exist, with footprint about 3 times as large as the SLH connector, 2 times as large as the UMPT terminal. • Experience with prototype testing boards gives confidence in connector stability in board-to-board connection; right-angle connectors may become available • Need to look at reducing termination board size in very tight PP0 physical space • The connector design and heterogeneous bundle suggest a cable termination board solution at the PP0 interface (and perhaps at PP1) • In the ”dual-ended” PP0 design we have two separate sub-bundles U.S. ATLAS ITk Pixel Workshop-- 2019-09-06

9. Electrical Tests • Connector testing: high current and dielectric withstanding voltage • Produced special testing boards for qualifying Samtec connectors • Tested pulling pins, and withstanding voltage increases linearly • Cirris Systems High-Voltage Tester (4250) • Adapter boards designed for bundle -to- termination-board -to- tester or bundle-to-tester • Define tests and store results in PC for any bundle design • We expect the specific tests will be similar to IBL testing procedures • The mix of local and ITk database records is not defined yet • It will be a good chance for us to exercise database design and interfaces U.S. ATLAS ITk Pixel Workshop-- 2019-09-06

10. Mechanical Tests + Irradiation • Mechanical flexibility tests underway • Temperature cycling (10 full cycles to start, not 420!), followed by visual inspection, bend tests, and withstanding voltage tests • Possible CTE mismatch for PEEK/Cu not a problem because PEEK will slide along Cu • Expect any expansion will be taken up near PP1 because bundles must be constrained in radius along the cable trays • We expect the liquid crystal polymer housing to be very radiation hard • No ATLAS results yet from irradiation campaigns • Gold-plated contacts are the standard; matte tin available for some models • Alignment of the miniature connectors is a challenge • Weld tabs (phosphor bronze) in precision slots may help with some models, but it will be difficult to have a multi-connector termination board U.S. ATLAS ITk Pixel Workshop-- 2019-09-06

11. Summary • Electrical components are well advanced, good interaction with PP0 • Excellent interaction with vendors • Trying to learn from IBL production experience for assembly procedures • Cable routing needs some work, even if bundle is dominated by twin-ax • On track for delivery of 19-2 prototype, except for unknown ”PP1” interface • Would we consider using a strip detector Glenair connector for prototype? • On-Detector Services PDR is still scheduled for late October • Dependent on finding a solution for Type-I service routing in Outer Barrel • Dependent on giving details of solution for service+cooling routing in Inner System U.S. ATLAS ITk Pixel Workshop-- 2019-09-06