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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
Entry  Sat May 15 09:50:31 2021, Team, Runs, Laser 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. :) 
Entry  Sat May 15 09:23:52 2021, Sebastian, Accelerator, Ekühler 
Tab "Kühler Elektronenstrahl"
An Gerät schicken
Entry  Sat May 15 09:22:41 2021, Sebastian , Accelerator, Ekühler  IMG-20210515-WA0000.jpgB5FE1031-7FFD-44D3-92B0-75E0784718D9.jpeg
Settings für Ekühler an und aus in SC4 und 
5
Entry  Sat May 15 06:51:16 2021, Night Shift Sebastian/Max/Noah, General, Different 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 :)
Entry  Sat May 15 03:39:16 2021, Team, General, actual revolution frequency 
frev = 1,2912735 MHz
Entry  Fri May 14 22:20:37 2021, Team, Accelerator, ESR Closed - BEAM #ON! 
 
Entry  Fri May 14 22:04:25 2021, Team, Accelerator, ESR OPEN ; NO BEAM -> Reset cooling device 
we had to open the ESR to reset a cooling device
Entry  Fri May 14 21:43:40 2021, Sebastian, General, "problems accelerator" 
There are cooling problems of some accelerator devices
short break, hopefully :)
Laser is switched of for some rest
Entry  Fri May 14 16:37:01 2021, Benedikt, General, Status 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.
Entry  Fri May 14 11:01:33 2021, Benedikt, Calibration, Laser 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".
Entry  Fri May 14 09:40:04 2021, Nightshift, Runs, Ecooling vs laser wavelength shift, coasting beam, laser stronger than Ecooling IMG-20210514-WA0017.jpg
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 
Entry  Fri May 14 09:38:43 2021, Nightshift, Runs, Coasting beam, ecooler on, scanning laser IMG-20210514-WA0019.jpg
 
Entry  Fri May 14 09:38:04 2021, Nightshift, Runs, Coasting beam, scanning laser, ecooler on IMG-20210514-WA0018.jpg
 
Entry  Fri May 14 09:35:20 2021, Nightshift, Runs, Coasting beam, scanning laser, ecooler on IMG-20210514-WA0018.jpg
 
Entry  Fri May 14 09:00:55 2021, Sebastian, General, UNILAC Problems 
~30 min downtime

--> LASER ADJUSTEMENTS!
Entry  Fri May 14 08:55:53 2021, Sebastian, General, ToDO 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
Entry  Fri May 14 07:33:42 2021, Team #Night, General, ecooler central frequency shifted relative to bunch central frequency 
 
Entry  Fri May 14 07:20:18 2021, Team #Night, General, actual bunching frequency 
25,82556 MHz
h = 20
Entry  Fri May 14 06:35:55 2021, Team #Night, General, Adjustment 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
Entry  Fri May 14 06:34:45 2021, Team #Night, Analysis, DSG821 IP 
140.181.104.108
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