Oven temperature increased, current up to 3.5E7 pps.
Found beam-target overlap setting horizontal bump in RO9 to -2.5mm.
Target T1 30.5K, density increasing to 2.6E11 at/cm2.
19:08 Run 32 start
Moving left detectors (79.69->34.66mm).
Beam energy 1.85 MeV/u nominal
Electron cooler actual values: voltage 1.051 kV, current 0.013215 uA, [voltage divider G35 1.0504 kV]
Stopped run, beam was still in bunch mode.
19:15 Run 33 start
All checks Ok.
Target at 3E11 at/cm2
Attachment 1-2 with rates and temperatures
20:20
Target density 3.4E11 at/cm2. Beam around 2.2-3.6E7 pps.
Checks ok! Spectra attached in att.3.
21:25
all good. Target density 4E11 at/cm^2
22:24
All checks are OK
Noted some variability in the injection intensity. For 15 minutes about half of shots were below 1e7. Perhaps some variability due to end of lithium in oven or increased temperture.
Beam calc with read values - Attachment 4
01:30
All checks OK. Injection intensity has stabilised ~2E7
Target density is stable ~4e11 at/cm2
02:44
Suddenly see very high rates in DSSD4. Detector had tripped. Tried to re-bias but kept tripping.
Set to 70V, leakage current is about 17uA but fluctuates quite wildly. Set to 50V and leakage current is about 6uA but again has wild fluctuations. Not sure of the cause, this detector is not moving and is far from the beam.
Decided to turn detector off to try and protect it. We can re-bias and monitor in the day tomorrow when we do not have beam on target.
This detector has tripped previously but was able to be re-biased at the time. See attachments 5 and 6 for the detector leakage currents.
New Run started R34.
Same conditions as before. DSSD4 turned off. To stop crap writing to disk I have set the corresponding FEEs to the MEC.
In principle we do not need this detector now as it is not moving to see the reaction.
Note I also observed in the system messages we semi regularly get a DHCP request from aida11. It seems to be functioning fine as I see the pulser signal in the spectrum browser. May be worth following up on at a later date. See attachment 7
All other checks OK
Data rate is now ~140 kB/sec
03:15
Tried to bias DSSD4 again. Leakage currents appear fine again.
Left for 5 minutes to gauge stability -> seems fine.
03:22
Have returned aida13, 14, 15, 16 back to LEC. Maintaing the same run (34)
Scratch that. 03:27 detector tripped again. Will just leave it off tonight. Turned those FEEs back to MEC.
06:00
I have quickly looked at Run 33. We clearly see the 7Be again in both detectors. Locus on detector much smaller than at higher energies.
All checks OK
07:07
Run stopped, switching to deuterium.
Detectors moved out
Shutter for gas target off.
Moved to next run -> no storage mode. |