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| Nuclear hyperfine mixing in 229Th89+ 2025 |
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 Tue Jun 24 12:25:34 2025, Carsten, Detectors, PMT behaviour - noise / PMT voltages / CFD Threshholds / CAEN Power supply (broken channel resetted)
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 Tue Jun 24 17:39:13 2025, Carsten, Stefan, Simon, Rima, Nils, Detectors, PMT behaviour - noise / PMT voltages / CFD Threshholds / CAEN Power supply (broken channel resetted)
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Message ID: 57
Entry time: Tue Jun 24 17:39:13 2025
In reply to: 55
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| Author: |
Carsten, Stefan, Simon, Rima, Nils |
| Category: |
Detectors |
| Subject: |
PMT behaviour - noise / PMT voltages / CFD Threshholds / CAEN Power supply (broken channel resetted) |
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PMT North and South have been changed:
CFD CH0: Middle Thr 7 / CAEN HV Ch1: 2750 V
CFD CH1: South Thr 8 / CAEN HV Ch2: 2700 V
CFD CH2: North Thr 8 / CAEN HV CH3: 2800 V
MESY CFD Ch4: Thr.17
MESY CFD Ch5: Thr.16
MESY CFD Ch6: Thr.20
| Quote: | In position North there is still the "old" 9423B PMT that draws quite some current.
On this detector threre is also some quite substantial noise. Very likely the base is not ok any more. Noise was much lesss for the other two PMTs.
Since position NORTH is the position with the largest sold angle, if there is another break from the accelerator we should exchange it against SOUTH.
It was also difficult to ramp up PMT north ; and I thought that againa channel broke (showing UnV not OVC (Overcurrent)). However, the PS is resetted if
you switch of the whole crate (aka switch the PS off). Before doing so, please ramp down the other channels slowly as intended.
Please leave the PMTs (besides you go in to exhchange the PMTs).
If you ramp pt PMT North (or the same detector at a different position), start with 2400 V and then slowly increase by steps of 50V.
Checked theresholds (but during injections, so in presence of electronic noise from injection). A further adjusted might be done later when we have measurement conditions.
(Or if we have time to exchange the PMTs).
Presently we have the following settings for CAEN:
CH1: Middle 2750 V, Thr 9
CH2: South 2700 V, Thr 7
CH3: North 2800 V, Thr 9 |
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