User name R. Michaels
Log entry time 17:41:55 on May27,2008
Entry number 239927
This entry is a followup to: 239885
keyword=R-HRS Cavity status
For the cavity monitors on R-HRS, here is the status (see fig 1
1. Cav1 is producing strange narrow signals on X,Y,Q. They do look
different from beam-off, so I suppose it's not a cabling problem.
Cav2, meanwhile, looks pretty normal (for e.g., see fig 1, top left)
2. Two channels are saturating. The ADCs work ok up to 8192, then
jump to 16384. All the channels are close to saturation at 15.8 uA.
Need to take access and reduce the ADC gate.
3. Despite these problems there is one combination of striplines
versus cavities that looks normal (see ellipse, bottom right).
(Why ellipse ? because of phases, etc). This involves Cav2 and
the remaining non-saturated channels. So, there is hope.
Things to do:
1. Reduce ADC gate. (10 min. access)
2. Fix Cav1 (issues unknown).
3. Need a pedestal run (forced gain=0).
Run plan once these are fixed:
1. Monitor beam current using HRS trigger. Plan to scan from 10 uA
down to 50 nA (at 50 nA the BCMs don't work).
2. At 10 uA, scan X (and later Y) using a steering magnet current I.
3. Repeat #2 with 1 uA, 0.1uA, 50 nA, etc. See if cavities work
(X,Y,Q track as expected) and measure the resolution.