HOME ESR EXPERIMENTS LABS etc
E121 E127 E132 E125 E143 laser_cooling_2021 E142 Ê128 E146 E0052 E0018 E0028 E0038 E0075 E0203_E0018 E0052_2025
  Dielectronic recombination-assisted laser spectroscopy, Page 3 of 6  Not logged in ELOG logo
 Find |  Login |  Help 
 Full | Summary | Threaded | Show attachments  Show only new entries    111 Entries 
Goto page Previous  1, 2, 3, 4, 5, 6   Next  All
ID Date Authordown Category Subject
  30   Tue May 10 21:41:17 2022 RodolfoAcceleratorT-Scraper
The T-Scrapers at the electron cooler have an issue. They can't be moved in the horizontal direction using the DeviceControl.
  34   Tue May 10 23:53:42 2022 RodolfoGeneralshift change
The night shift took over. They are trying now to overlap the ion and laser beams.
  44   Wed May 11 14:59:01 2022 RodolfoLaserLaser status
I have measured the output energy of the laser system. All values in [mJ] and over 500 laser-pulses average

DateOut of Quanta Ray @ 532 nmSeed energy for Cobra @ 532 nmOut of Cobra @ 601 nm
10.05.202253348571
11.05.202248448067
  70   Mon May 16 15:57:37 2022 RodolfoLaserWavemeter calibration
I have calibrated our Wavemeter WS7 using the temperature stabilized He-Ne Laser (SIOS EN60 825-1:2014). In the screenshots below you can see the readout of the wavemeter before (vor) and after (nach) calibration.
  82   Fri May 27 14:57:23 2022 RodolfoLaserLaser Energy
I have started up the laser system (Q-Ray & Cobra) again. Here some parameters*:

- Q-Ray's output energy (@532 nm: 547 mJ.
- Seed energy for Cobra# (@532 nm): 504 mJ.
- Cobra's output energy (@ 601.7 nm): 71 mJ.

* all values averaged over 500 pulses.
# angle of lambda/2-plate: 107°
  108   Wed Jun 1 17:20:04 2022 RodolfoLaserHeNe @ WS7
  111   Fri Jan 13 17:05:22 2023 RodolfoLaserTesting WS6
Testing the new Wavemeter (HighFinesse, WS6, SN3950) with the QRAY laser light @ 532 nm. Multimode fiber von High Finesse:FC/PC S (Corning, MM, OM2)
  112   Wed Jan 18 13:02:12 2023 RodolfoLaserTesting WS6 with Cobra
Testing the WS6 (S.N. 3950) together with the Cobra.

Cobra operated with dye DCM in Ethanol + DMSO (Concentration 1:1)
- Oscillator concentration 0.3 g/l.
- Main amplifier concentration 0.0375 g/l (1/8 oscillator concentration).
- Laser linewidth: 6 GHz. Expansion factor: 10x. Grating: 2400 g/mm (40/2013)

Seed energy: 504 mJ @ 532 nm.
Cobra output energy: 112 mJ @ 640 nm.

Scan settings: 640.0 nm - 639.8 nm @ 0.005 nm / step.

Wavemeter settings: Pulsed (ext. trigg. 1 = QRay-Output: Lamp Sync). Precision: Fine.
- Wavemeter calibration. Reference source: Neon lamp.
- LTA-Data under ATPPC023 D:\WLM6 LTA data\D:\WLM6 (18.01.2023, 11.23, 640,10656 nm.lta)
  113   Tue Jun 6 09:33:00 2023 RodolfoLaserFiber coupler
Cobra's new fiber-coupling unit for wavelength reading.
  56   Thu May 12 10:21:30 2022 Ragan, Shahab, Simon, Sebastian, Christopher, WilfriedGeneralNo Beam
There is no beam in the ESR due to some problem in the UNILAC.
  57   Thu May 12 11:30:18 2022 Ragan, Shahab, Simon, Sebastian, Christopher, WilfriedGeneralBeam is back
Beam is back in the ESR.
  59   Thu May 12 12:02:56 2022 Ragan, Shahab, Simon, Sebastian, Christopher, WilfriedGeneralNo beam
There is no beam in the ESR again.
  60   Thu May 12 12:51:30 2022 Ragan, Shahab, Simon, Sebastian, Christopher, WilfriedGeneralBeam is back
12:50 Beam is back again in the ring.
12:52-until now Kicker problem in the ESR.
  69   Mon May 16 14:20:05 2022 Ragan, Danyal, Carsten, Phillip, Wilfried et al.GeneralE128 Beamtime 
> Dear all,
> 
> unfortunately, the E128 experiment must now come to an early end. 
> The problem(s) with the injection septum are severe and no work around solution (with acceptable risks) could be found. 
> Several things were tried, but without hope. 
> 
> Many thanks to everybody involved during the preparation time and the shifts during the beamtime. 
> 
> Best wishes,
> 
> Wilfried

There is beam again in the ESR. The plan is to take beam until tomorrow morning.
  29   Tue May 10 20:35:42 2022 Phillip, Wilfried, MaxDetectorsPMT Threshold
Since we have ions in the ring now, we looked at the PMT thresholds and the widths. In order to do so we looked at the Raw Signal directly before the CFD and its output simultaneously. You can now set the threshold just above the noise. If the threshold is too low you will also see flat lines in the oscilloscope when triggered on the CFD output. New values:

PMT Mitte
---
Width: 200 -> 220 (60ns -> 90ns)
Threshold: 20 -> 5

PMT Nord
---
Width: 200 -> 220 (60ns -> 90ns)
Threshold: 12 -> 10

PMT Süd
---
blind.
  48   Wed May 11 22:04:30 2022 Phillip, Wilfried, MaxGeneralspacial laser - ion overlap verified
After the SIS/ESR optimization we checked the spatial overlap with the T-scrapers again.

The values are:
devicemove in dir.scratch (mm)gone (mm)
GECEDS1VUup -3.0 -2.2
GECEDS1HAright -22.9 -22.0
left -11.0 -13.0
GECEDS2VUup -4.5 -2.7
GECEDS2HAright -21.0 -19.6
left -7.8 -8.4


The beam position is approx. as before. The laser position is still good and we have spatial overlap.
  53   Thu May 12 00:16:13 2022 Patrick, Volker, Guy, Rui-JiuRunsRuns night shift

Time SIS-intensity ESR-intensity after orbit change cooler-HV LMD-DAQ2 file nr LMD-DAQ1 file nr scan range(nm) step width increment (nm) dwell time(s) n loops comments
00:15 ~1.0e8 1.0e7 223219 433 - 435 8094 601.62 - 601.405 0.005 5s 4
00:47 3.7e8 2.0e7 223219 436 - 440 8095 - 8096 601.62 - 601.405 0.005 5s 8 increased to 15 injections, still not saturated
Tried 20 injections, got no injection into ESR, so moved back to 15. The scrapers were not moving for quiet some time, even after fixing them. The problem may have been that two ParamModi windows were opened. The injection into the SIS does not work when there are other users performing special operations with the machines.
02:28 1.0e8 1.0e7 223220 441 - 444 8097 601.62 - 601.405 0.005 5s 6
02:54 2.8e8 1.7e7 223219 445 - 449 8098 - 8099 601.62 - 601.405 0.005 5s 6
03:21 ~3e8 ~2e7 223219 DAQ did not write 8100 - 8101 601.62 - 601.405 0.005 5s 6
The vacuum gauge of the e-cooler failed. It was restarted. Apparently, upon changing/fixing anything related to our accelerator pattern, the scrapers forget to move. Then they have to be disabled and enabled again in ParamModi. Also, the injection does not work very well. Either the transition from SIS to ESR fails or we are just skipped completely. After fixing the injection, again the scrapers failed as expected. We keep the scrapers out now.
04:34 2.8e8 1.8e7 223219 DAQ failed, started late 454 - 458 8102 - 8103 601.62 - 601.405 0.005 5s 6 Set max.counts in PMT middle and north to 15 (In file 'SetConditions.C', applied when starting go4). No scrapers used.
05:02 2.5e8 1.7e7 223219 DAQ late, 461 - 464 8104 - 8105 601.62 - 601.405 0.005 5s 6
05:30 2.5e8 1.8e7 223219 465 - 469 8106 - 8107 601.62 - 601.405 0.005 5s 6 Set max.counts in PMT middle and north to 20.
05:57 2.5e8 1.7e7 223219 470 - 474 8108 - 8109 601.62 - 601.405 0.005 5s 6
06:25 2.6e8 1.7e7 223219 475 - 479 8110 - 8111 601.62 - 601.405 0.005 5s 6
06:50 2.4e8 1.6e7 223219 480 - 484 8112 - 8113 601.62 - 601.405 0.005 5s 6
07:24 2.2e8 1.5e7 223219 485 - 489 8114 - 8115 601.62 - 601.405 0.005 5s 6
07:49 - 6.5e6 223219 490 - 493 8116 601.62 - 601.405 0.005 5s 6 UNILAC tunnel will be open for ~1h -> no new beam from SIS available
08:15 - 2.6e6 223219 494 - 496 8117 601.62 - 601.405 0.005 5s 6 UNILAC tunnel will be open for ~1h -> no new beam from SIS available
  37   Wed May 11 03:17:14 2022 Patrick, Volker, Guy RunsStart laser scanning
Runs of the night shift. The wavelength range is 601.95 - 601.735 nm.
We started the wavemeter python script on atppc023 located in Desktop/wavemeter_Bi.
We changed the wavelength range in go4 to the actual scan range.

Questions:
There are many other masses/isotopes/etc. visible in the Shottky spectrum. Is this wanted?
Are the vacuum gauges turned off?
Laser timing correct? +- 3 bins?

TimeSIS-intensitycooler-HVLMD-DAQ2 file nr LMD-DAQ1 file nr scan range(nm)step width(nm)dwell time(s)comments
03:30 ?e7 223218 373 8073 601.95 - 601.735 0.005 5s 2 loops
03:38 9.0e7 223218 374-377 8074 601.95 - 601.735 0.005 5s 8 loops from now on
04:15 8.4e7 223218 378 - 381 8075 601.95 - 601.735 0.005 5s
04:49 7.4e7 223217 382 - 385 8076 601.95 - 601.735 0.005 5s
05:23 6.4e7 223216 386 - 388 8078 601.95 - 601.735 0.005 5s 8077 was skipped due to some "server socket locked"-error
05:59 8.9e7 223218 389 - 391 8079 601.95 - 601.735 0.005 5s
  36   Wed May 11 03:10:55 2022 Patrick, Sebastian, Volker, Guy LaserLaser - bunch timing
We added the delay and gate generator in between the bunch trigger and the CFD to move the timing of the PMT middle signal relative to the photodiodes north and south.
The center value of PD-North is at 19 bins, PD-South at 55 bins, the middle is therefore at 37 bins. The PMT peak should be half a revolution, ie 75 bins further in the histogram, giving a peak position of 112, from which then 3 bins are subtracted to account for the distance of the PMT-middle from the center of the straight section. So all in all the delay is adjusted so the PMT-middle peak appears at 109 bins (see attached plot).
  35   Wed May 11 01:09:07 2022 Patrick, Sebastian, Volker, GuyLaserBeam overlap
We overlapped the laser with the ion beam.

The ion beam positions are:
devicemove in dir.scratch (mm)gone (mm)gone + 4.5 (mm)x0 (mm)
GECEDS1VUup -3.0 -2.71.8
GECEDS1HAright -21.9 -20.9 -16.4 -4.7
left -12.0 -13.1
GECEDS2VUup -3.8 -2.91.6
GECEDS2HAright -19.2 -18.4 -13.9in [-0.1, 4.3]
left -9.0 -9.7

We used the "gone + 4.5" column where the scraper is in the middle of the ion beam to adjust the laser.

Picture 1: Final beam position.
Picture 2: Final MRC settings.

Note 1: By switching to the "real" bunching frequency, the laser went out of the stabilization. We restarted the MRC system and shifted the laser back into position with the piezo mirror, looking at the first screen (without amplifiers!).
After enabling everything again, the before found settings did not correspond to the correct beam position anymore, so we overlapped again.

Note 2: After the repositioning, the horizontal screw was at its limit and the beam stabilization failed. We moved the screw away from the limit while still hitting the screen and restarted the MRC system. The laser could then be stabilized again.
Goto page Previous  1, 2, 3, 4, 5, 6   Next  All
ELOG V3.1.5-fc6679b