BTOF demonstrator/mechanics meeting

→ US/Pacific
Description

https://ucsc.zoom.us/j/98299273347?pwd=HHm9tGM6hD7aZaIVWWaF16ueAT3gVu.1

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Quick recap

The meeting focused on updates and discussions related to the design and assembly of detector components, particularly staves, sensors, and FPCs. Simone Mazza reported on gluing trials and the assembly of another critical experiment. Grigory provided an update on the design of component loading jigs, mentioning feedback from the machine shop and plans for metrology to assess assembly tolerances. Dan presented initial design thoughts for the stave, including dimensions, material choices, and cooling tube options, sparking a detailed discussion on stave width, FPC size, sensor coverage, and the impact on electronics and physics performance. The group debated the trade-offs between achieving full phi coverage and the practical limitations of narrowing the FPC, with input from Elke, Itaru, Tonko, Rachid, and others. Dan also shared results from structural and thermal analyses, indicating reasonable deflection and temperature gradients. The conversation ended with a request to upload the slides and a mention of future discussions on service hybrid design.

Next steps

  • Grigory: Follow up with the machine shop for feedback on the 1st version of the component loading jig design by next week.
  • Grigory: Perform metrology of positioning on the first iteration of the jig assemblies, targeting 50-70 micron tolerances.
  • Simone Mazza: Aim for a glue thickness of 50-100 microns in future assembly trials, using shims for control.
  • Anish: Prepare slides to show the structural deflection analysis results for the two-layer and three-layer designs at the next meeting.
  • Tonko: Send an email in 5-7 days to organize a follow-up meeting regarding the FPC width options (50mm, 55mm, 60mm) with Takashi and others.
  • Elke: Sit down with someone to write down the different stave/FPC/sensor width options, analyze the pros, cons, and risks, and perform a risk analysis for the project.
  • Itaru: Verify the FPC signal line pitch (70 micron) and voltage drop in the next prototype.
  • Tonko: Send an email to Simone Mazza with a slim list of people to invite for the next meeting on the service hybrid design.

Summary

Gluing Trials and Part Assembly

Simone Mazza reported that their team conducted additional gluing trials and was busy assembling a critical part for another experiment. No other updates were provided before the meeting transitioned to waiting for Dan's slides.

Component Loading Jigs Design Review

Grigory reported that the first version of the component loading jigs design was sent to the machine shop for feedback, expected next week. The team discussed targeting a positioning tolerance between 50-70 microns for sensors and FCFD components, with Simone Mazza confirming that glue thickness should be controlled between 50-100 microns using shims to ensure proper component placement. Grigory mentioned that his colleague who was supposed to present next week is sick, but they hope to proceed with metrology testing of the assemblies once the initial feedback is received.

Stave Design and Prototyping Approach

Dan presented his initial design approach for a stave, detailing specifications including thickness, width, and length, as well as the placement of ASICs and sensors. He proposed using square cooling tubes and side channels for additional rigidity and wire bonding support. Dan suggested producing both short prototypes from off-the-shelf components and full-length prototypes to test various materials and validate performance metrics. He also discussed coverage challenges related to sensor overlap at larger eta values and presented calculations for different stave widths to achieve optimal fly coverage.

FPC Width Options Discussion

The team discussed FPC (Flexible Printed Circuit) width options, with current simulations showing that a 70 micrometer pitch can work within a 50 millimeter width without severe crosstalk. Itaru confirmed that while simulations indicate no significant crosstalk issues, prototype verification is still needed. The group is waiting for feedback from Takashi regarding the feasibility of 50 and 55 millimeter FPC options, with a follow-up meeting planned in 1-2 weeks. The team also discussed alternative approaches including potentially increasing the silicon sensor width to maintain 100% coverage without narrowing the FPC, though this would require careful consideration of timing impacts.

Stave Design and Manufacturing Options

The team discussed design options for stave dimensions, with Rachid suggesting 55mm is more reasonable than 50mm and 60mm being practical for design. Hansheng confirmed the 50mm width would have a 5-degree opening angle between staves, resulting in 144 pieces for the staves. Elke raised concerns about the project's official EIC status, emphasizing the need to document all design options, calculate yields, and conduct risk analysis for different approaches, particularly regarding FPC manufacturing and performance considerations.

Detector Project Acceptance Specifications

The team discussed acceptance specifications for a detector project, with Fuqiang questioning whether small differences in acceptance rates (like 90% vs 95% vs 100%) would significantly impact performance. John reported that outreach to physics working groups has begun to establish reasonable performance specifications, noting that current acceptance rates are around 90% for ADA and FI coverage. Dan presented FEA analysis results showing stave deflections of about 1.25 millimeters, which were deemed acceptable, and thermal analysis showing uniform temperature gradients of a few degrees Celsius. The team agreed to schedule a follow-up meeting to discuss detailed design options, with Hansheng to send an email with a limited list of invitees.
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