 Wed Apr 20 10:09:50 2022, Rodolfo, Laser, Optic with spots 
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The average energy produced by the laser along the beamtime was about 10 mJ/puls. After about two weeks of beamtime some of the optics, especially the optic
placed just after the BBO crystall, got some spots, see pictures below. Here the diameter of the laser beam is about 6 mm. |
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Sat Apr 16 04:19:05 2022, Patrick, Simon, Alex, Sarper, Runs, Runs night + morning shifts 16.04.
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Runs of the night shift 16.04. after changing the wavelength range. The new range is 320.12 - 319.859 nm. The step size was decreased from 0.002 nm to 0.001
nm.
The goal was to have the same number of scans as before (261), however, the scan range in the labview program could not be set accordingly. We decided |
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Fri Apr 15 20:43:18 2022, Konstantin, Laser, Dye changed
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| Dye of the laser system has been changed. UV laser power increased from ~8 mJ to 11 mJ pulse energy. |
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Fri Apr 15 12:53:25 2022, Max, Danyal, Laser, checked laser pulse energy after change in wavelength range
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previous scan range:
the laser pulse energy @ 320.62 nm was ~11 mJ
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Fri Apr 15 12:42:18 2022, Max, Danyal, Carsten, Konstantin, Patrick, Simon, General, laser wavelength range changed: 320.12 - 319.60 nm
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Runs of the morning/afternoon/night shift. The wavelength range is now 320.12 - 319.60 nm.
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Thu Apr 14 22:44:40 2022, Patrick, Simon, Danyal, Max, Runs, Runs night shift 14./15.04.
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Runs of the night shift. The wavelength range is 320.62 - 320.10 nm.
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Thu Apr 14 19:46:46 2022, Sarper & Konstantin & Rodolfo, Laser, Laser power
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We checked the laser power before starting the new scan range.
- Seed energy before Cobra @ 532 nm: 513 mJ (before 499 mJ).
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Thu Apr 14 17:47:55 2022, Carsten, Rodolfo, Konstantin, Sarper, Runs, Afternoon shift runs 14.04 changing the wavelength scan range
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The new scan range is changed from [B]321.12 - 320.60 nm to 320.62 - 320.10 nm[/B]
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Thu Apr 14 12:38:38 2022, Sebastian, Detectors, XUV / Cu checkups
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Check regularly if the connection to the XUV and Cu detectors are still active and the detectors move in (after injection) and out (after killing the ion
beam).
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Thu Apr 14 12:27:18 2022, Sebastian, Max, Detectors, Connection to XUV / Cu reestablished!
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The connection to the XUV and Cu were lost during the nightshift.
The XUV detector was in the park position,
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Thu Apr 14 10:57:11 2022, Carsten, Accelerator, Maintanence UNILAC / Op training
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We had no beam since about 1000. Also, we are still trying to find out why we have such a low intensity in the expereimnt.
Presently, there is a planned maintenance in the UNILAC, beam is expected back in 25-30 mins.
The profile grid TE3 in the transfer beamline in front of the target will be used to check if the extracted SIS beam has changed compared to before the |
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Thu Apr 14 08:41:42 2022, Carsten, Accelerator, Low intensity at the experiment after series of failures during the night
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After the recovery from the failures during the night, we see much lower intensity at the experiment (measured with the particle detector count rate).
Instead of 8000-10000 cts we see only 3000-4000cts at comparable SIS intensities.
Also ESR cooler seems to be slightly unstable (wiggling lines) during injection. However, it is visually evident from the Schottky that the injected intensity |
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Thu Apr 14 06:29:18 2022, Max, Sebastian, Accelerator, lesser ESR injection intensity
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We now have less ESR injection intensity (see screenshot attached).
This can also be seen in the count rate after "UNILAC/SIS failures".
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Wed Apr 13 15:41:29 2022, Rodolfo & Sarper, Laser, Laser status
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We have checked the power of the laser and optimized it "a bit".
- Seed energy for the Cobra @ 532 nm: 508 mJ (before 496 mJ)*
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Wed Apr 13 14:29:04 2022, Carsten, Rodolfo, Sarper, David, Pierre-Michel, Max, Sebastian, Runs, Afternoon - morning shift runs 13.+14.04.
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Changed the wavelength scan range from [B]321.62 - 321.10 nm[/B] to [B][B]321.12 - 320.60[/B] nm[/B] after one scan.
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Tue Apr 12 21:56:54 2022, Volker, David, Pierre-Michel & Danyal, Alexandre, Sebastian, General, new laser wavelength scan range 321.62 - 321.10 nm
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New wavelength scan range is [B]321.62 - 321.10 nm[/B]. Before the new scan range (compare old scan range in [URL=https://elog.gsi.de/esr/E142/215] Entry
215[/URL]) was applied,
the cooler settings were slightly modified. Current was changed from [B]50 mA to 40 mA[/B], correction voltage was changed from [B]3943 V to 3948 V[/B]. |
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Tue Apr 12 17:01:30 2022, Konstantin, Detectors, Voltage PMT North
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| Voltage of PMT North has been increased from 2500 V to 2600 V. Additionally the threshold was adapted from 25 mV to 12 mV. |
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Tue Apr 12 15:05:56 2022, Rodolfo, Laser, Laser status
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We have checked the laser power at 14:15 *
- Pump energy after Q-Ray @ 532nm: 559 mJ.
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Tue Apr 12 14:52:19 2022, Rodolfo, Detectors, PMT Nord, Middle. Datasheets
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Attached are the datasheets for the solar-blind PMTs.
- PMT Nord. Type 9423. SN: 650
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Tue Apr 12 13:24:40 2022, Alexandre, Sebastian, Detectors, Sideband in Schottky
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Sometimes we see a broad sideband at lesser schottky frequencies to the high intensity thorium beam.
Pic 1 shows the relative broad sideband on the left.
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 Tue Apr 12 14:11:52 2022, Ragan, Detectors, Sideband in Schottky
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> Sometimes we see a broad sideband at lesser Schottky frequencies to the high-intensity thorium beam.
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> Pic 1 shows the relative broad sideband on the left.
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