[BTeam] Elevated chronic beam loss in NL

[Jay Benesch]

https://logbooks.jlab.org/entry/3927857  by Pavel

The level of the chronic beam loss in NL has become much higher (a 
factor of ~3-5) around 8 pm as measured by the NDX detectors. Neutron 
readout is above the readout saturation in NL23. The photon channels are 
not saturated, showing the dose rates about 1 kR/h, and up to ~2kR/h in 
spikes. I will decrease the integration time to 0.5 sec to allow for 
higher dynamic range.

We should discuss this at B team.

If lem was a significant driver, efforts to understand what went wrong 
with the beam-based gradient calibration data taken in August should be 
elevated and a beam studies of just a few zones scheduled to see if the 
problem repeats.  https://opsweb.acc.jlab.org/CSUEApps/atlis/task/22480
The average scaling factor found in August was ~0.8 while the lem fudge 
factor is 1.012 aka the gradient-weighted scaling factor should be 
~1.01.  Chris and Adam have reanalyzed the data taken in August and it 
looks clean.  We're at a loss.  New eyes needed.

In addition, thought should be given to changing the NL optics so as to 
increase beta function on lower passes and decrease it on the higher 
passes.

What happened overnight:

https://logbooks.jlab.org/entry/3927791
https://logbooks.jlab.org/entry/3927845
https://logbooks.jlab.org/entry/3927849
https://logbooks.jlab.org/entry/3927946
https://logbooks.jlab.org/entry/3927975

Brian did a little steering 4R into 5L around the time things quieted 
down in the NDXs.