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Agenda
- Run 69 (GeHV n,gamma NR calibration) status
- DCRC refurb?
- DCRC55(1) is at FNAL for Sten to test. Unknown how long it will take him.
- PuBe source availability:
- there is one block of a couple weeks around April when we can borrow it
- Kevin is amenable to weekend use - it would need to be returned on Sunday for 24-hour activation before Monday classes
- Kevin said we can use it the week before and the week of Spring Break, needed back the Monday after break. (March 9-25.)
- Tower assembly complete.
- We'll probably try the heat-sinking modification (previous analysis). Note: primary noise is HV-leakage-related, this is a secondary consideration. Options:
- leave 4K heat sinks to tower disconnected
- leave 4K shield stage off completely
- thermally anchor tower's 4K stage to its 600 mK stage
- Ideas about producing extra IR to test whether it affects observed charge leakage
- Calibration source:
- Smoke-detector Am source mounted at center of detector Side 2 (bias side), as in the last run.
- The detector was kept in the source safe with the Cf-252 source for 2 weeks to preactivate it. (Currently source in its small poly container is with detector in purge cabinet.)
- Run 68 (n,gamma with S101) analysis:
- Working on analysis task list
- Data not yet looked at:
- Trigger study data: now processed
- Hold-time runs at different biases done, haven't looked at them yet
- Have reprocessed -80V Na data. Used -125V balancing factors, still need to check if those are optimal (if not we should redo it)
- Future 150mm runs
- 150mm w/phonons - need to design 600mK rod to accommodate 150mm cans
- Received 4/3-inch DIBs from TAMU - now we can house either detector for phonon readout (would need to machine faces on 4/3-inch housing for DIBs)
- S1501 and S1502 sent back to TAMU
- We have decided we can run 8 phonon channels
- Preferred DIB-pad layout: two DIBs separated by 120 degrees
- Himangshu's mask design: PDF download
- Will use existing vacuum-interface electrode, mounted on side opposite the phonon side
- Will connect directly to two DCRCs, with one diverter board to route one tower wire to HV connection
- We'll want LEDs - are there some mounted on the DIBs? We can mount external LEDs too - existing electrode has mounts.
- First 150mm phonon detector will be monolithic, but “donut+hole” arrangement (active veto) proposed as well.
- Aiming for May to finish fabrication and start run.
- Other future runs
- Future HVeV runs?
- Berkeley can help us with a Soudan-style housing mount (3“ or 4”?)
- then use original tower, can try different heatsinking for colder SQUID card
- would need to install optical fiber
- through top or through stripline tube? need vacuum feedthrough
- Look at Prisca's deuterium lamp/monochromator/filters, glass UV fiber
- Is PuBe NR calibration feasible?
- 1×1×0.4 cm^3 is 630× smaller than SNOLAB detector. Anthony estimates 25 events/day (over full spectrum) for Si, 250 events/day for Ge. any chance we could get multiple chips?
- Nick's idea: sandwich between two 4“ Ge detectors for gamma coincidence (large solid angle coverage)
- Other ideas:
- run SiHV with Nick's movable Am source (or with multiple Am sources)
- run SiHV with no 4K heatsinking
- re-run USD1? do we have any additional ideas to test it?
- anything else?