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Agenda
- Run 70 (GeHV n,gamma NR calibration)
- Setup:
- Replaced standard 4K heat-sinking.
- Changed how we wire HV to the electrode to bypass SQUET
- Modified one unused SQUET channel by shorting the TES leads. The purpose is to study noise, IbIs etc during cooling to get a better handle on the SQUID card temperature.
- Status: After several blockages at 77K, managed to get it to work this weekend and are now at 4K
- Found and repaired a leak in the Still line last week.
- Did a few cleanings and got another blockage
- Did a bunch more cleanings, only through cold trap 1
- Did LN2 transfer while circulating some mix through fridge lines and periodic throughput tests
- Cooled to LHe on Sunday, some strangeness with exchange gas pressures
- Move forward with some noise tests and cooling to base today
- Lab
- Leak detector: verified that rough pump does not pump below a few mbar. Email exchange with Pfeiffer - they suggested a possible bad part in the pump and sent a pump manual, so we can try disassembling and assessing. The manual also has part numbers for replacements so we should be able to get those if necessary. Could be that we just need to clean the parts - we'll see whether they look gummed up from old oil.
- Sten has returned DCRC55(1) (we've been doing OK without it though. Should ask him again in a couple weeks if he has time to look at it.)
- PuBe source: plan is to take over the source on our permit, house it in PAN443b, the right cleanroom. We've been storing it in the steel box there with lead, now we will use the “howitzer”.
- Helium recovery:
- Calculations suggest we are only collecting 17% of 4He pump exhaust. After pump rebuild, hoping for improvement this time.
- Run 68 (n,gamma with S101) analysis:
- Working on analysis task list
- Simulation. 1 day of livetime acquired.
- Data not yet looked at:
- Trigger study data
- 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?