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  Laser Cooling Experiment 2021, Page 2 of 5  Not logged in ELOG logo
New entries since:Thu Jan 1 01:00:00 1970
ID Date Author Category Subject
  65   Sat May 15 09:50:31 2021 TeamRunsLaser cooling of....
H=2
H=7
H=10
H=20
H=30

We performed several scans:
Close to the bucket middle
Over the bucket
Over the bucket, jumped to the "red side" 
of the bucket and captured and cooled the 
beam again.

Laser settings:
7 times revolution frequency and 740ps 
pulses - - > 3.4 +/- 1.2 GHz

Still to do:
Switch to 240ps pulses - - > 5.8GHz 
+/-1.3 GHz

Maybe:
Switch to 117ps pulses - - > 11.0 +/- 0.8 GHz
BUT here we have less laser power (max. 50 mW right after BBO crystal, so maybe only 30 mW at the laser-ion overlap)
available. Maybe we are lucky and it is 
enough to cool also the ion beam. :) 
  64   Sat May 15 09:23:52 2021 SebastianAcceleratorEkühler
Tab "Kühler Elektronenstrahl"
An Gerät schicken
  63   Sat May 15 09:22:41 2021 Sebastian AcceleratorEkühler
Settings für Ekühler an und aus in SC4 und 
5
  62   Sat May 15 06:51:16 2021 Night Shift Sebastian/Max/NoahGeneralDifferent Laserscantypes
We use different scan types (manual scan) or constant laser wavelengths to check the effects of laser cooling in the Schottky diagrams (fluorescence can not be seen in the detector), for different bunching amplitudes and frequencies:
- Scan from 1028.950 -> 1028.940, stepsize 0.001 every 10 sec
- Scan from 1028.950 -> 1028.930, stepsize 0.001 every 5 sec
- Scan from 1028.950 -> 1028.940 -> 1029.950, stepsize 0.001 every 5 sec
- Scan from 1028.950 -> 1028.940, stepsize 0.0005 "as fast as possible" 
- constant wavelengths around 1028.940
- Scan to wavelengths < 1028.940 (heating) -> Jump to 1028.945 and fast scan back to 1028.940 (-> cooling)

The cooling effects of the laser can be observed well in the Schottky spectra :)
  61   Sat May 15 03:39:16 2021 TeamGeneralactual revolution frequency
frev = 1,2912735 MHz
  60   Fri May 14 22:20:37 2021 TeamAcceleratorESR Closed - BEAM #ON!
  59   Fri May 14 22:04:25 2021 TeamAcceleratorESR OPEN ; NO BEAM -> Reset cooling device
we had to open the ESR to reset a cooling device
  58   Fri May 14 21:43:40 2021 SebastianGeneral"problems accelerator"
There are cooling problems of some accelerator devices
short break, hopefully :)
Laser is switched of for some rest
  57   Fri May 14 16:37:01 2021 BenediktGeneralStatus update
Right now, we have to adjust the ion beam a bit to overlap better with the laser beam.
We keep the laser wavelength at resonance with the ions and try to optimize the fluorescence signal on the XUV detector while moving the ion beam.
  56   Fri May 14 11:01:33 2021 BenediktCalibrationLaser Beam adjusted
The laser beam was adjusted in his position to overlap better with the ions.

Ion beam is destroyed at scraper position 1VO 6 mm and 2VO 4 mm; the laser beam looses half its power at 1VO 6mm and 2VO 4 mm.

EDIT: In the Schottky spectrum, we saw a stronger "cut" from the laser beam with slightly different settings in the TEM system. Later today, we could maybe finetune the ion-laser overlap while observing this "cut".
  55   Fri May 14 09:40:04 2021 NightshiftRunsEcooling vs laser wavelength shift, coasting beam, laser stronger than Ecooling
Last three pictures where taken after 
first laser ion beam overlap adjustments

It seems to be that the interactions are 
better. We also see the laser earlier and 
stronger in the schottky 
  54   Fri May 14 09:38:43 2021 NightshiftRunsCoasting beam, ecooler on, scanning laser
  53   Fri May 14 09:38:04 2021 NightshiftRunsCoasting beam, scanning laser, ecooler on
  Draft   Fri May 14 09:35:20 2021 NightshiftRunsCoasting beam, scanning laser, ecooler on
  51   Fri May 14 09:00:55 2021 SebastianGeneralUNILAC Problems
~30 min downtime

--> LASER ADJUSTEMENTS!
  50   Fri May 14 08:55:53 2021 SebastianGeneralToDO 14.5 ...so far
1.) ion lasser overlap and scraper test

2.) change bunching frequency to middle of ecooled coasting beam

3.) long time measurements see labbook HKR
3.1) try ecooler on/off ; bunch on / off ; laser fixed on / off ; laser scanning on / off ; try different bunching amplitudes (MAX :LEV 0.25V) ; try other h = 10, 7, etc...
3.2) Dont forget to plug in the schottky trigger -> maybe change acquisition and analysis time if needed

4.) XUV detector tests
4.1.) laser - bunch timing by checking xuv anode signal
  Draft   Fri May 14 07:33:42 2021 Team #NightGeneralecooler central frequency shifted relative to bunch central frequency
  48   Fri May 14 07:20:18 2021 Team #NightGeneralactual bunching frequency
25,82556 MHz
h = 20
  47   Fri May 14 06:35:55 2021 Team #NightGeneralAdjustment of Laser
we increased the height of the laser beam

TEM Settings
OffsM Ay -0,07
OffsM By -0,35

1VO scratches 6
2VO scratches 3-4
  46   Fri May 14 06:34:45 2021 Team #NightAnalysisDSG821 IP
140.181.104.108
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