Guest appearances by: Wouter (RC), Alex, Dustin, Rupesh, Klaus...
16:00 Status at start of shift:
- In Controlled Access, trying to recover Right HRS magnets. Counting House
is very warm, but AC is being worked on.
16:25 Wouter is ramping RQ2. The other Right Arm HRS magnets are on, at P0=2.8 GeV (i.e. about 90% of where we want to be). Left HRS magnets are all essentially off. RQ2 trips at 1150A. Wouter and I go into Hall to reset the power supply.
16:45 RQ2 tripped again at 1150 A; Wouter and I go in yet again to reset the prower supply.
16:50 Counting House A/C is repaired.
17:20 RQ2 continues to trip at about 1150 A; we have tried a total of 4 times in the last 90 minutes, and each time the same issue. It seems to be a power supply problem, not a cryogenic issue, as far as we can tell.
17:30 Start discussions on what can be done while waiting for power supply repairs....
17:20 Heidi Fansler called us. Having read the elog, she suggested that we try increasing the lead flows on Right Q2 by 10% or so.
Initially, we read 90 l/m on the left readout and 120 l/m on the right
readout from Hall A Tool.
Wouter and I enter the Hall, locate the
valves, and adjust to produce new lead flows: 104 l/m and 135 l/m.
Now we turn on the magnet. Ramps happily all the way to 1400 A!
More details are in Entry 296469.
19:22 Ask MCC for a harp scan. Results in ELog Results are for A: σx=208 µm and σy=178 µm; and for B: σx=119 µm and σy=385 µm. We are concerned that we are focussing too much in x (and defocusing too much in y), and so ask MCC to adjust if possible.
20:00 New Harp scan, after MCC has tweaked quads:
Results are for A: σx=189
µm and σy=118
µm; and for B:
σx=224 µm and σy=268
µm.
This looks better; ask for 10x10 raster, and will do
Spot++.
20:10: Spot++ looks OK (despite BPMA being unavailable to RHRS DAQ). We now go to Loop 1 (20 cm hydrogen target, first time this has been in the beam in this experiment). However the Target Motion GUI does not allow us to move there; this location appears to have been disabled in the GUI.
We page Dave Meekins, and he will call Chris Keith and have him re-enable that target location in the GUI.
20:30 Dustin is here. We ask for Target motion to be masked, and we will go the Carbon "hole" target, to check beam alignment in preparation for Q2. Meanwhile, Dave Meekins calls back, and the motion to Loop 1 is now enabled; we check that it indeed appears to be the case. Ask for 10 µA on hole target.
20:55 Dustin says that hole appears nicely centered as seen with rastered beam. Now go to Loop 1, hydrogen target. Target does not seem to get to exact nominal position when it stops, so we call Dave Meekins again.
21:13 Dave looks at target remotely; he decides he needs to come in, as he believes there is a target lifter problem, and he will have to have an access to investigate.
23:30 During Target initial tests with beam (as we ramp it up) we end up with seeing the target not regulate properly. Goes too cold with beam on, does not increase the HP heater enough. PID problem? Call Dave Meekins (poor guy..)
It seems the "beam compensation" has some sort of software issue. We note that it appears that the wrong dE/dx was loaded for the cell properties; Dave has fixed this, but it still does not seem to be working. Dave suspects a software issue, and turns off beam compensation for now. Should be OK for the weekend - it will just not compensate as rapidly as ideally to a beam trip... will live with this for now...
23:45: Raster = 10mm x 10 mmm
Loop 1 Hydrogen
Beam Current HP Heater Fan Speed JT Valve coolant µA (W) (Hz) (%) (g/s) 5 445 48 50 14 20 323 48 50 14 20 280 60 50 14 20 350 60 51 15.2 20 515 60 57 18 40 390 60 57 18 60 230 60 57 18 80 80 60 57 18 Target seems not to be regulating here ; sits at 18.88 K, not 19.0 K. Call Dave Meekins (again. sorry Dave...) He finds a problem in the Beam Compensation software, and for now we have turned off beam compensation. 80 140 60 57 18.2 80 215 60 58.6 19.2 98 80 60 58.6 19.20:00 Shift ends, hand over to next crew...