ELOG CARME

AIDA GELINA BRIKEN nToF CRIB ISOLDE CIRCE nTOFCapture DESPEC DTAS EDI_PSA 179Ta CARME StellarModelling DCF K40

CARME

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Entry time:	Tue Apr 8 14:13:01 2025
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> 09:09 Arrived at GSI for comissioning beamtime. > CARME currently in a stopped state, with all FEEs powered off. > Upper detector is biased with 80V and has a leakage current of 9.92uA. > This is up on the previous recording by JM of 5.4uA recorded in elog 187. > It is possible light is reaching the detector via the interaction chamber which shall be checked. > > 09:19 Cave checked: > Water is running to the FEEs (OK for power on when required) > There are 4 uncovered windows on the interaction chamber. Will see if we can get these covered. > > 14:29 Tested different bias voltages. > Between 80V and 120V got a normal diode response with small increases in leakage current > At 120V leakage current was stable at 9.92 for one minute. > Checked waveforms on DAQ and looked at current again and it was up to 16uA. > Turned off bias and let ramp down. > Now when trying to ramp up detector in similar position to last week with a diode response between 0-30V and a rapid increase above that. > Carlo spoke to Gleb who was beam tuning. Which around the time of our trip he opened the valves and put beam into the ring for a rotation. > Gleb put in several faraday cups prior to the CARME chamber yet we still see the non-diode bias characteristics. > He will enter in 30 minutes and we will check if anything looks out of place. Will also remove motor pin to give option of movement. > > 15:00 Gleb and Carlo enters the cave. > Dipole and beam off. > Pin removed. > Diode response restored 9.4uA at 40V. Which is only slightly above where it was during the morning > > > Before they got anywhere with starting again the current has gone up again.. > > 16:49 Since around 15:30 the current has come down to its levels earlier today at 40V. We are preparing a script to monitor the current levels going forward. > > 17:00 Gleb stopped tuning the beam for the day. > There is no beam in the ring. > Magnets and everything else continue as if there was beam in the ring. > > 19:40 Attempted to raise bias to 50. Immediately started to trip > Carlo cycled motors multiple times. > Bias in out position dropped. > To lower > Have made it to 60V. Will leave there overnight with leakage current tracking running. > > No beam so no daq running. Encoding: HTML ELCode plain Suppress Email notification

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