Zoom link: https://uzh.zoom.us/j/5166204490?pwd=VUt1VmFLVmJsYTExeXJka0JwbUlIQT09

Attendance: Gordon, Andrey, Emma, Maurice

Meeting recordings:

* There was a meeting last week * Task and rought estimates for cryogenic meeting was schedule * Cryogenic CDR in October, PDR of both in Feb? * Starting to work with Matt and Julien on Vibrations, needs vibration specs * BP: Start wiki and we start populating

1. CDR Report report

1. Investigate use of clean steel or iron to replace stainless steel. Steel could be cleaner and less expensive than stainless. 5 cm of magnetic steel may be sufficient to eliminate the need for the mu metal shield
   • Cleanliness requirements make us prefer SS
   • Need to confirm with simulations and other experiments
   • Iron radiopurity less well controlled
   • What is the upper limit on magnetic shield
   • Investigate which experiments were built with iron or carbon steel
2. Lead handling will need to conform to laboratory and DOE standards. The requirements for handling lead should be investigated. Any coating will need to be accounted for in the stacking design (space of coating), in the shielding calculations (leaks), and in the cost estimate.
   • Sylvia takes care of that
3. Identify site-specific seismic requirements and confirm structures conform to them
   • LSM needs to provide the information
4. Put a compliant element between structure and rollers. This will allow track roller to self align with the track and guarantee load distribution between the 4 roller.
   • Sounded like a good idea, Andrey will design it. Will not drive costs or effort significantly
5. Confirm scope of which items that are assumed will be contributed by French collaborators, for example we had discussion about material screening and support structures for rail system on which the experiment sits.
   • Need design of support structure, costing, plan.
   • Others, discuss LSM
6. The neck of the cryostat currently has unacceptable stress margins (Ultimate stress FOS ~ 1.1 over proof load). Improve to yield stress FOS at least >= 2 over proof load, preferably FOS >= 3. Check seismic loads both vertical and horizontal directions.
   1. about 15mm of weld fillet will reduce stress considerably (can this be done with electron welding?)
   2. collar is an alternative, work in progress
   3. gussets not improvement
   4. perhaps thickening of the neck
7. Perform an analysis to determine the resonance frequencies of the cryostat structure. This is a start to considering vibration issues and possible mitigations.
   1. Check few mode shapes between of some key frequencies (pumps, 50Hz, phonon-roll off f, PT)
8. Consider whether the extra complexity of chamfering the corners of the shielding would be reasonable, to save limited space in the lab site
   1. Likely will drive costs a lot, hard to get quotes without full design
9. The Basis of Estimate is about two years old. Continue to update it, ensuring that all activities are covered in their appropriate (recently reworked) WBS, that nothing has slipped through the cracks, and that low-level estimates match the totals.
10. Validate DR pressure relief and setpoint.