Straw bi-weekly meeting

Tuesday 16 Sept 2025, 09:00 → 10:00 Europe/Zurich

20/1-004 (CERN)

Hans Danielsson (CERN)

To be followed up:

• long prototype - tooling alignment and check after installation
• crimp tube and plug design - experience from the short prototype
• Temur - straw diameter 4.85mm +0um -50um

 

09:00 → 10:00 Updates

STUDY LONG STRAW PROTOTYPE 15_09_25.pdf

STUDY LONG STRAW PROTOTYPE 15_09_25.pptx

Short prototype:

Michal:

• 1 straw glued and wired
• 99 g for wire tensioning, old wire 30 um
• checked the wire afer unrolling, gold layer is OK

 

Tonio: 

• need to improve the crimping technique (shock, copper pin bent after crimping)
• maybe we should change to an electric crimping tool
• need to produce a tool to help insert the crimp tube in the plug

 

Hans: 

• documentation!
• we should check with Stefano if the wire doesn't break in the crimp tube after crimping

 

Intermediate prototype:

Michal:

• frames and spacers already at CERN
• need to decide on straws 

Long 124-straw prototype:

Zuzana:

• Minitubes crimp tubes delivered last week, first QC measurements done, remaining tests to be finished this week (Stefano) 
  • 3/30 crimp tubes blocked for 75um and 30um wire
  • OD of the bottom part mostly out of reference (60-70%)
  • unwanted material at the cone end in some cases
  • hole concentricity to be understood
  • https://edms.cern.ch/ui/#!master/navigator/document?D:101852292:101852292:approvalAndComments

Hans:

• no news about the supporting tube (CERN workshop, Euromec)
• no news about spacers, but they are ordered

 

Vincent:

• removed plastic pieces for centering of the supporting tube  - already done by the vacuum tube
• protection of spacers serve also as quides during insertion of the supporting tube
• sent a file with HV board "design" to Peter
• 15mm between holes for screws on the HV board
• have to add alignment holes on the HV board (possibly between two holes)
• sent info to Marija for calculation of the deflection
• added ball bearings (Omnitrack) on the supporting tube (flange) to simplify insertion in the vacuum tube
• need information about positioning of the vacuum tube in the beam to add alignment holes (8H7) on both sides
• gluing system - two supports on the sides, multiple top plates to allow gluing of all straws, alignment with pins; need to finalize the position of holes in relation to the gas manifold
• to do list on the last slide

 

Francois: 

• we need to look where to order the bearings and springs for gluing
• removed a bit of excess material on the welds

 

Temur:

• brought some straws, but they were damaged during the transport (bent or pressed)
• 128 long straws for next years - no problem
• needs 1 roll for tuning of the machine, at least 3 rolls (100 m of straws per roll), 19 um
• in Pisa, they have 5mm straws, 20um wire, old Atlas crimping tool, they wire in vertical position with a small weight on the wire during insertion
• better to use wire sppol which is not vacuum sealed, rather stored in argon atmosphere to avoid "welding"
• should check threshold of elastic-inelastic transition of the wire

 

Michal:

• will pressurize the straws