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BTOF demonstrator/mechanics meeting
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US/Pacific
Description
https://ucsc.zoom.us/j/98299273347?pwd=HHm9tGM6hD7aZaIVWWaF16ueAT3gVu.1
Quick recap
The meeting focused on the mechanical and electrical design of the stave and service hybrid, especially the available space at the end of the stave for electronics. Tonko and others discussed the uncertainty in the total physical length of the stave and how much space was left for the service hybrid, with different numbers from various presentations and the need for a precise value. There was extensive discussion about whether the service hybrid should be mounted on, decoupled from, or embedded in the stave, with Rachid emphasizing the importance of being able to dismount and replace electronics without discarding the whole stave. The group also debated the modular approach versus building full staves, with Rachid advocating for full-stave assembly to reduce cost and risk, while **Simone Mazza**, Grigory, and others pointed out the existing infrastructure, equipment costs, and risks of switching strategies at this late stage. Elke raised concerns about the impact of design choices on acceptance and efficiency, noting that new simulation results were expected. Ihit and Grigory presented updates on the design and prototyping of jigs for sensor and ASIC placement, including metrology requirements and plans for using dummy components. Finally, there was a brief update on dummy sensors and chips, as well as logistical information about the KK test beam and accommodation.
Next steps
- Simone Mazza: Send an email to Andy (and copy Dan, Kakos, and others) to clarify the physical length of the stave and the usable space for the service hybrid, including the effective length and bending radii of cables.
- Takashi: Confirm with the FPC manufacturing company that the 50 mm FPC design (including connector routing) is correct and feasible.
- Grigory: Send damaged/broken full-size sensors to the team working on the jigs for assembly testing.
- Satoshi: Arrange for the production and distribution of dummy sensors (few hundred) to US institutions for assembly process finalization.
- Grigory: Register the student for the KK test beam, using the provided spreadsheet and hostel information.
Summary
Service Hybrid Measurement Discussion
The team discussed a 5 centimeter proposal for the service hybrid, with Tonko questioning the physical length of the stave and whether 21 centimeters would be available for the service hybrid. Tonko noted that different presentations showed varying measurements between 131 and 135 centimeters, and emphasized the need to confirm the exact physical length before proceeding. Hansheng acknowledged uncertainty about the feasibility of 21 centimeters and agreed to consult with Andy for clarification.
TOF System Space Planning
The team discussed space constraints for electronics in a 2675mm total barrel TOF system. Tonko emphasized the need for exact measurements to the millimeter level for effective space planning, particularly regarding the central membrane and mechanical support structures. Elke clarified that the current support structure uses shelves rather than a central structure, which should help with space allocation. The team agreed to start working with the 2675mm envelope and divide the space accordingly, though specific details about the effective surface area and acceptance surface placement still need to be determined.
Service Hybrid Component Design Discussion
Rachid raised concerns about the design of the service hybrid component, questioning whether it should be mounted on, embedded in, or decoupled from the stave. Tonko explained the current design shows the service hybrid mounted on the carbon fiber stave, taking advantage of its cooling, but acknowledged this was not necessarily the only option. Rachid emphasized the importance of clearly defining the relationship between the service hybrid and stave to avoid complications, expressing preference for a design that allows for the service hybrid to be replaced without removing the entire stave.
Carbon Fiber Board Mounting Design
Rachid and Tonko discussed the design and mounting of boards on carbon fiber staves, emphasizing the need for components to be removable without replacing the entire stave. They debated various mounting methods, including screws and thermal considerations, with Simone Mazza suggesting the use of thermal paste and potential cooling loops. The conversation also touched on the dimensions of the service hybrid area and some confusion regarding measurements in the current design.
FPC Cable Routing Design Challenges
The team discussed design challenges with cable routing and bending radii in their current FPC layout, with Tonko expressing concerns about potential issues if cable specifications change. Elke suggested involving Roland and Dan to review the cable layout model, while Rachid proposed alternative approaches including mounting LDOs behind ASICs and simpler modular designs based on previous project experiences. The team agreed to schedule a follow-up discussion with additional stakeholders to address the cable routing concerns and explore the proposed design modifications.
Full-Stave vs Modular Assembly Discussion
Rachid advocated for a full-stave approach instead of modular assembly, estimating it could save $1-2 million while reducing risks and complexity. Several participants, including Simone Mazza and Grigory, expressed concerns about the technical challenges and high costs of full-stave assembly equipment, with Grigory specifically noting that wire bonder equipment alone would cost around $1 million. The discussion highlighted the need for further consideration of both technical feasibility and cost implications before making a final decision on the assembly approach.
Clean Room Facility Challenges
The team discussed challenges with clean room facilities and equipment setup across different institutions, with Grigory highlighting that not all facilities have the necessary large clean room space that BNL currently has. Simone Mazza agreed to send an email to Andy to clarify the usable space on the stave, particularly regarding the 5 centimeter case, and suggested including Dan who is also working on the table. Takashi provided calculations showing that a 50 millimeter FPC could fit in the connector, but the team expressed concerns about confirming these calculations with the production company and considering the impact on acceptance and efficiency. Elke raised concerns about recent simulations showing additional acceptance losses when including certain problems, emphasizing the need for more guidance on acceptable levels of acceptance loss before finalizing the stave design.
U8 Jigs Project Progress Update
Simone Mazza mentioned ongoing work with new results expected from U8, which will be a primary focus before making decisions. Ihit presented updates on the jigs project, detailing the precision and dimensions of chip components, source and target jigs, and 3D printed prototypes. The design has been passed to the machine shop, and the first version with modifications will be produced in about two weeks.
Sensor Assembly and Testing Progress
The team discussed progress on sensor assembly and testing, with Grigory explaining they are working on a mock-up using laser cutting for components and stainless steel for the frame. Simone Mazza confirmed they have broken sensors from the first production run that could be sent for testing, and Satoshi announced they are preparing dummy chips for assembly with several hundred dummy sensors to be distributed. The team also addressed logistics for an upcoming KK test beam, with Satoshi sharing a spreadsheet for shift scheduling and confirming hostel accommodation availability at KK.
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