[Bteam] hall C halo and tail

[Jay Benesch]

Mike Tiefenback has a long entry about the errors of our (Ops) ways in 
dealing with bunch formation imperfections by running the SL 1.6 degrees 
off crest to get Compton scintillator rates down.

http://opweb.acc.jlab.org/CSUEApps/elog02/elog_item.php?elog_id=1659323

Dispersion was checked in the C line and adjusted in the vertical plane; 
horizontal was fine.

Brandi has an annotated elog showing some of the investigation this 
morning.
http://opweb.acc.jlab.org/CSUEApps/elog02/elog_item.php?elog_id=1659650

Clyde elogs about a slow quarter CM anomaly that's been present since 
the 6MSD.  It wasn't there before the 6MSD.
http://opweb.acc.jlab.org/CSUEApps/elog02/elog_item.php?elog_id=1659647

Terry Carlino suggested taking the NL off crest instead of the SL so the 
BLM activity in arc 1 would also be reduced.  Suggestion was made after 
everything was stable, so we didn't.

I suggested to Terry, and now suggest to the B team, that we go back to 
finite M56 in the injector chicane to compress the bunch for the rest of 
the 6 GeV era.  We know there's a problem in one or both of the injector 
CMs.  We know that we're not going to get sufficient fast diagnostics to 
find it before the beam shuts down.  We know that 0L04 CM is going to be 
replaced with a "C100" and new LLRF controls.  Let's inelegantly solve 
the problem for the rest of the run.

Discuss Tuesday?

Jay