Notes on Run 1422:

Request was 3 cycles of 40, 20, 10, 5, 2.5 muA. 

It became immediately clear MCC could not really support 40 muA. (The RF was supposedly OK, but the Machine Protection System was tripping on instantaneous beam loss spikes.) 

Got one so-so point at 40 muA, then revised plan to 3 cycles of 35, 20, 10, 5, 2.5 muA. 

We therefore got 16 beam-on data points.

Initial fits revealed one outlier with an 0.8 muA fit residual. (Roughly 4 sigma.) The Unser is getting old. Removed the outlier, leaving 15 good, beam-on data points. 

No other significant issues with the calibration BCM1, BCM2, BCM4A, or BCM4C.

The gain of BCM4B is too high, saturating somewhere above 20 muA. (The weakest link in the relevant electronics chain appears to be the V/F hitting its 1 MHz celing.) The input to the digital receiver already has an attenuator on it from when I carefully tuned it several years ago. I routinely power cycle the DRs before a run to restore them to a known combination of internal gain x internal attenuator settings, but even then the gain of BCM4B appears to be a crapshoot every year.