Slide 1: Barrel Harness Status • • • • Problems with DORIC4A. Tolerances and fibre layout. Harness status in Taiwan. Harness testing at RAL. T. Weidberg SCT-SG 6th May '03 1
Slide 2: DORIC4A problems • DORIC4As tested on wafer and only good die were given to Taiwan. • Yield of DORIC4As when mounted on doglegs was ~ 50%. ESD precautions were used at Radiantech but…clear evidence of ESD damage seen ( photos). T. Weidberg SCT-SG 6th May '03 2
Slide 3: DORIC4A Solutions • Process changed to avoid sharp pointers and use automatic die bonding. • 122 DORIC4As now mounted on doglegs and all tested to work. • Don’t want to use DORIC4As mounted on doglegs before procedure was changed because of worries about long term reliability. • Difficult to re-work doglegs because of cover. T. Weidberg SCT-SG 6th May '03 3
Slide 4: Harness Lengths • Better definition of tolerances and which lengths are the critical ones to measure. – i/f PCB to PPB1: -0 + 20 mm – i/f PCB to MT connectors: -0 + 20 mm – Position of MT splice +/- 10mm or up to -50mm if splice needs to be redone. • Detailed harness engineering drawings showing fibre layout and check lengths ( figure). T. Weidberg SCT-SG 6th May '03 4
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Slide 7: Fibre Layout • Jigs produced in order to ensure correct fibre loops for fibres leaving doglegs before harness clip. • Photo shows prototype jig. T. Weidberg SCT-SG 6th May '03 7
Slide 8: Schedule • Batch process so many steps well advanced: – Opto-packages for 55 harnesses. – Doglegs assembled for 23 harnesses. • • • • • • 4 Harness completed May 5th 20 Harness completed May 13th 36 Harness completed May 15th 64 Harnesses (all B3) by May 31st Complete all barrel harnesses by August 25th. See schedule on web: – http://www-pnp.physics.ox.ac.uk/~weidberg/production/Barrel_Harness_Schedule.xls SCT-SG 6th May '03 8 T. Weidberg
Slide 9: Harness Testing at RAL • Complete system for bench testing barrel harnesses is working at RAL and was used to test the first two barrel harnesses. Software ok. • Current system requires temporary cables to be connected to PPB1. • Upgrade test system to use TPPs and TIs. The TPPs and TIs would then stay with the harness during subsequent assembly of harness to barrel. – Minimise number of connections made to PPB1. – TIs and TPPs should be available in ~ 1 week. • System for testing harness on barrels still being developed. – Loop back PCBs (send TTC  data links) – Simple cheap BER test system being made by Minglee (end May). – Allows for BER testing of 4 harnesses in parallel (could be done overnight). • Testing Harnesses on receipt of barrels at Oxford. – Simple loop back PCB tested and works. – Requires ROD software to use this (Peter Phillips). T. Weidberg SCT-SG 6th May '03 9