Straw bi-weekly meeting

Tuesday 14 Oct 2025, 09:00 → 10:00 Europe/Zurich

20/1-004 (CERN)

Hans Danielsson (CERN)

To be followed up:

• short prototype - validation, measurements (wire tension, straw straightness, HV, ...), FE board
• Toshiba wire investigation - results
• long prototype - Alu tube measurements - results, update drawings of flanges, launch the production
• Minitubes crimp tubes investigation - results
• measure alignment of spacers in the intermediate prototype
• updated HV board drawing from Vincent with the central hole 
• documentation of procedures and results

09:00 → 10:00 Updates

Central electronic card pawn 13_10_25.pdf

Central electronic card pawn 13_10_25.pptx

masks.png

Short prototype:

Michal:

• started writing documentation in Overleaf
  • crimping procedure
  • notes from Zuzana and Hans
  • Hans: store on EDMS
• VNA analysis failed (not conclusive)
  • idea: build a different setup with custom boards
• HV test with gas flow
  • 5 h at 1800V - one discharge
  • 1900V - immediately a lot of discharges
  • don't know where the discharges are - investigation needed
  • the current without discharges is <1nA
  • HV connectors were tested in 2019 (Peter) - no issue with HV up to 2kV
  • possible issues with cleanlines of HV board or connectors (Johan)

 

Hans:

• need to document the results of all tests - EDMS

 

Peter: 

• found a good chip for the charge preamp board, waiting to receive the board

 

Johan:

• design of the evaluation board (not for the HV) is almost finished (2.4 mm PCB)
• it is expected to have several rounds of tests to get the final design
• 5-6 weeks waiting time

 

Intermediate prototype:

Tonio:

• Dubna straws 19um hold 4.5 bar pressure (absolute) at least

 

Michal:

• wants to measure straw sag as a function of straw tension
  • not great with a device from Neil
  • different idea with laser
    
    

Hans:

• is it clear that the spacers are perfectly aligned with the frame?
• you can measure it with a wire
• need to document the results of all tests - EDMS

Long 124-straw prototype:

Vincent:

• provided step files for parts masking the Ultem parts before coating
• provided solution for central pillar supporting the HV board

 

Peter: 

• pillar for HV board - bottom part plastic, top part metal would be OK, size is OK
• needs and updated version of the HV board "design"

 

Zuzana:

• Minitubes crimp tubes 
  • investigation of a blocked tube ongoing
  • need to review copper hardness and tolerances
  • asked Tonio&Francois to perform a pull test on 3 crimp tubes
• Ultem parts (HV plugs)
  • investigating possibility to sputter just the underlayer (Ti + 3um Cu) and electroplate the gold layer
    • this will require a change in the outer diameter (+10-15um on diameter due to copper underlayer)
    • should be cheaper
    • need to be tested as bath might not be an option due to scratching of parts

 

Hans:

•  no news from Francisco about the spacers - will contact the company again
• no news from the main workshop about the supporting tube
• asked Temur to make 12um straws (Michal gave 3 spools 12um to Lamina) after they make more 19um before Christmas