BTOF demonstrator/mechanics meeting

→ US/Pacific
Description

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

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Quick recap

The meeting covered updates on sensor performance, structural simulations, and assembly jig designs. Satoshi presented results showing reduced performance at the edge of the sensor, prompting discussion about increasing overlap between sensors. Anish shared structural simulation results for trays holding staves, confirming around 1.2 mm sagging and noting that no clearance violations occurred. Grigory provided an update on jig designs for sensor and ASIC assembly, discussing alignment precision requirements and the use of pins or kinetic couplings. Dan offered feedback on the jig design, suggesting the use of two pins instead of four to avoid binding issues and recommending design adjustments for better precision and visibility. The discussion also touched on material tolerances and the handling of components during assembly.

Next steps

  • Satoshi: Prepare and check the performance at the other edge of the sensor and present the results next week.
  • Anish: Compile a bigger slide deck with structural simulation results for trays around the BTOF and confirm the face sheet thickness (1mm vs 0.5mm) with Dr. Young and Sushil.
  • Grigory: Contact the machine shop for updates on the jig drawings and adjust the design based on their feedback (consider reducing number of pins, chamfering, perpendicularity, and size of jig).
  • Grigory: Reach out to Arthur or directly to TSMC to obtain the production tolerances for the FCFDs.
  • Grigory: Update the jig design to incorporate vacuum suction for the sensor and refine the handling procedure for the ASICs, considering glue thickness and alignment precision.

Summary

Sensor Performance Issues Discussion

The team discussed sensor performance issues, particularly focusing on poor performance at the edge of the sensor compared to other areas. Satoshi presented laser results showing performance differences in the z-direction, while Simone Mazza noted that increasing overlap might help address the ETA gaps but could affect position resolution. The team agreed to continue monitoring performance data, with Satoshi planning to provide updates on the other side of the sensor and the strip-to-strip performance next week.

Structural Simulation Results Review

Anish presented structural simulation results for trays holding staves in a two-layer design, showing approximately 1.2 millimeter displacement or sagging at the center, which aligns with previous results from Simone Mazza. The model included carbon face sheets and foam core with a total mass representative of the actual stave, though detailed components like cooling tubes were not explicitly modeled. Anish proposed adding longitudinal beams between trays for enhanced structural stability, and noted that all materials including trays and support structures are made of carbon fiber.

Sensor Assembly Jig Development Update

Grigory provided an update on the development of jigs for sensor and ASIC assembly, highlighting current specifications, manufacturing tolerances, and design considerations. The team is waiting for feedback from the machine shop on the pin design and tolerances, aiming for an alignment precision of 50-70 microns. Grigory noted that while kinetic couplings could improve positioning, they were not pursued due to current constraints, and vacuum suction will be used for component placement. Next steps include contacting the machine shop for updated drawings and planning metrology tests using 5-10 jig prototypes.

Precision Assembly Alignment Pin Design

Dan and Grigory discussed the design of alignment pins for a precision assembly process. They agreed that two or three pins would be sufficient instead of four, with Dan recommending the use of pins combined with a hole and slot in the mating component, along with chamfered edges for easier alignment. The team also discussed reducing the size of the assembly fixture to allow better visibility during placement, and addressed concerns about component tolerances and glue thickness requirements of 50-200 microns. Simone Mazza mentioned that the loading jig could be used to apply pressure during curing to prevent floating of the components in the epoxy.
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