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Entry  Thu Mar 5 22:35:43 2015, Zach, DailyProgress, SiFi - ringdown, Taiwan room-temp Q > 10^5, cooling now Taiwan_ringdown_106Hz_300K_fullvacuum.jpg
    Reply  Fri Mar 6 19:02:28 2015, Zach, DailyProgress, SiFi - ringdown, Q at low temperature after reclamp… worse? ActivePhi_Taiwan_106Hz_100K_3_6_15.png
       Reply  Tue Mar 10 03:51:42 2015, Zach, DailyProgress, SiFi - ringdown, Taiwan cantilever long-term low-temperature phi ActivePhi_Taiwan_106Hz_100K_longterm_3_6_15.png
Message ID: 1216     Entry time: Thu Mar 5 22:35:43 2015     Reply to this: 1217
Author: Zach 
Type: DailyProgress 
Category: SiFi - ringdown 
Subject: Taiwan room-temp Q > 10^5, cooling now 

On Tuesday night, when I added the Si spacer to the clamp, I measured a Q of ~46000, but I noted that it had been increasing up to that point, likely due to the residual gas damping (see CRYO:1214). Last night, I made another measurement and found it to be much higher, at ~1.2 x 105 (tau ~ 350 s). This is much better than we have seen at room temperature thus far, so it looks like my spacer addition has helped.

I remeasured this an hour or so later and saw no appreciable increase. I checked again today and it appears as though it may have increased slightly, but it was hard to say for sure due to higher environmental noise. Really, we need the steady-state ringdown to make a good measurement at this level.

The LN2 dewar was refilled today, so I filled the cryostat and we'll see how it looks at low temperature tomorrow.

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