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  Laser Cooling Experiment 2021, Page 1 of 5  Not logged in ELOG logo
Entry  Fri May 14 09:35:20 2021, Nightshift, Runs, Coasting beam, scanning laser, ecooler on IMG-20210514-WA0018.jpg
 
Entry  Fri May 14 09:38:04 2021, Nightshift, Runs, Coasting beam, scanning laser, ecooler on IMG-20210514-WA0018.jpg
 
Entry  Fri May 14 09:38:43 2021, Nightshift, Runs, Coasting beam, ecooler on, scanning laser IMG-20210514-WA0019.jpg
 
Entry  Fri May 14 09:40:04 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  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 09:57:24 2021, Dayshift, Runs, Currently on schedule  
Enhance fluorescence rate and perform 
laser bunch timing 

Right now: Performing several detector tests with scanning laser (triangle) between 1028.930 and 1028.950 nm. Eccoler current @ 10 mA
Entry  Mon May 10 07:58:13 2021, Danyal, General, Telephone numbers and Zoom link 
Telephone numbers:

ESR laser lab: +49 (0)6159 71 - 2882
ESR measurement hut: +49 (0)6159 71 - 2880
HKR (main control room): +49 (0)6159 71 - 2317 or 2245

here is the zoom information:

https://tu-darmstadt.zoom.us/j/2183997317?pwd=WGc2TEkxYlEyNFhMWm02bFhqRnRVUT09

Meeting-ID: 218 399 7317
Passwort: 481607
Entry  Tue May 11 15:49:30 2021, Danyal, General, setting up ESR 
The operators are still busy extracting the beam from the SIS18 towards the ESR and injecting it into the ESR. 
Entry  Tue May 11 18:29:35 2021, Danyal, General, first ions in the ESR first_ions_are_injected.jpg
 
Entry  Tue May 11 20:14:43 2021, Danyal, General, bad ESR vacuum 
I just heard that the ESR vacuum is quite bad. 
There was a small vacuum problem a while ago, it was sealed, but apparently the pressure is not as low as usual.

Markus Steck said that the beam lifetime is only 15 - 20 seconds !!! 

This will seriously complicate some of our test experiments :( 
Entry  Wed May 12 02:34:29 2021, Danyal, General, instabilities in ion frequency fluctuations.jpg
The ion beam moves around, pretty arbitrary. See picture. 
ESR crew believes that it is not due to fluctuations in the HV of the E-Cooler. 
    Reply  Wed May 12 08:10:17 2021, Lars, General, instabilities in ion frequency 
looks like the E-Cooler is responsible for this. If one turns off the electron current, the beam stays stable. 
M.Steck is informed.

> The ion beam moves around, pretty arbitrary. See picture. 
> ESR crew believes that it is not due to fluctuations in the HV of the E-Cooler. 
Entry  Wed May 12 09:59:08 2021, Benedikt, General, Rigol DSG821 signal generator settings CF7701F6-86BE-406C-8FAD-F3161463181C.jpeg
 
Entry  Wed May 12 18:59:15 2021, Ken Ueberholz, General, Power is back 
Power is back and most things are running again
Entry  Wed May 12 19:48:24 2021, Sebastian, General, DSG821 Network IMG_20210512_195329_resized_20210512_075346417.jpg
To implement the bunch Signal Generator (DSG821 inside ESR) you have to:

1. unplug the Ethernet cable
2. under System / io config set the ip address
3. set Sub mask
4. set DNS
5. very important: than press Apply!
6. plug in Ethernet cable
7. than a message like "successfully connected to network" should show up
8. you can crosscheck the Settings by pressing the "eye symbol"
Entry  Wed May 12 22:28:55 2021, Ken Ueberholz, General, Bunching succesfull 
Bunching with 2 and 10 bunches succesfull
Entry  Wed May 12 22:35:33 2021, Danyal, General, frev and fb 
Schottky frequency (189th harmonic) = 244.033662 MHz

revolution frequency  frev = 1.2911834 MHz

bunching frequency h=2  --> fb = 2.582367 MHz
bunching frequency h=10  --> fb = 12.911834 MHz
Entry  Wed May 12 22:48:25 2021, Sebastian, General, DSG Control SCPI Commands 
Open Ultra Sigma
Press LAN
Press Search, after a while the whole rigol devices are shown. Press ok
Than you see the DSG821 (140.181.104.108) as online
right click -> open SCPI Command Terminal


*IDN?                 check for remote control
:FREQ 1.291MHz        set the RF Frequency to 1.291MHz
:FREQ?                return current frequency
:LEV 0.2V             set the amplitude to 200mV
:LEV?                 return current amplitude
:OUTP ON / OFF        set RF output ON or OFF
:OUTP?                returns 0 if output is OFF, returns 1 if output is ON

after some time there is an automatic logout of the scpi command panel. Close the panel and reopen the SCPI Command Terminal again to reconnect to DSG821 Signalgenerator. 
If this does not work, close the whole ultra sigma program, also in the taskbar (right click -> exit) and execute Ultra Sigma Program again
Entry  Wed May 12 22:57:41 2021, Sebastian, General, Laser Reprate 
laser reprate is seven times the revoolution frequency: 9.038283 MHz
pulse length: 735ps
Entry  Wed May 12 23:45:23 2021, Ken Ueberholz, General, Laser does not reach the exit window 
High rates on the detector at 50mm positions, laser does not seem to reach the exit window.
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