User name R. Michaels
Log entry time 01:16:28 on August16,2005
Entry number 152106
Followups:
keyword=Cavity update / summary of statusCavities look fine this evening, after Musson's gain change earlier
today (halog 152004). Spectr. Run 2468. See fig 1 & 2, Amplitude distribution
and correlation to striplines looks good but not better than before.
Summary of the status:
1. The noise floor causes the glitch in the amplitude distribution
in the middle of the raster orbit. We may eventually fix this by increasing
pre-gain but the implications for HAPPEX are negligible if
the resolution is as good as we think.
2. HAPPEX DAQ resolution is <= 10 um. Seeing if it is better than
this requires a careful regression analysis. Spectrometer DAQ
resolution appears to be worse (expected), prelim: <= 120 um.
3. The phase offsets and gains are fine. We don't need to touch
them anymore during HAPPEX. The insensitivity to phase offset is
understood but I won't try to explain it here.
4. The frequency response has a bandpass of 60 kHz (approx). This
does not matter for HAPPEX, and it may eventually be improved
to 200 kHz, which would be helpful to counting experiments.
5. There have been rare reliability problems. The PLL may get out
of lock, requiring an IOC reboot. When the reboot occurs the default
gains may be wrong (this will be fixed ASAP, I'm told). We must
improve the routine diagnostics and recovery procedures.
6. Diagnostic: Run Podd analyzer on a 50K run, as you would for
spot++, and run the macro as directed: .x online.C+("cavities")
FIGURE 1
FIGURE 2
