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  Laser Cooling Experiment 2021, Page 1 of 5  Not logged in ELOG logo
New entries since:Thu Jan 1 01:00:00 1970
ID Date Author Categorydown Subject
  Draft   Fri May 14 09:35:20 2021 NightshiftRunsCoasting beam, scanning laser, ecooler on
Attachment 1: IMG-20210514-WA0018.jpg
IMG-20210514-WA0018.jpg
  53   Fri May 14 09:38:04 2021 NightshiftRunsCoasting beam, scanning laser, ecooler on
Attachment 1: IMG-20210514-WA0018.jpg
IMG-20210514-WA0018.jpg
  54   Fri May 14 09:38:43 2021 NightshiftRunsCoasting beam, ecooler on, scanning laser
Attachment 1: IMG-20210514-WA0019.jpg
IMG-20210514-WA0019.jpg
  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 
Attachment 1: IMG-20210514-WA0017.jpg
IMG-20210514-WA0017.jpg
  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. :) 
  66   Sat May 15 09:57:24 2021 DayshiftRunsCurrently 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
  1   Mon May 10 07:58:13 2021 DanyalGeneralTelephone 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
  2   Tue May 11 15:49:30 2021 DanyalGeneralsetting up ESR
The operators are still busy extracting the beam from the SIS18 towards the ESR and injecting it into the ESR. 
  5   Tue May 11 18:29:35 2021 DanyalGeneralfirst ions in the ESR
Attachment 1: first_ions_are_injected.jpg
first_ions_are_injected.jpg
  6   Tue May 11 20:14:43 2021 DanyalGeneralbad 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 :( 
  8   Wed May 12 02:34:29 2021 DanyalGeneralinstabilities in ion frequency
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. 
Attachment 1: fluctuations.jpg
fluctuations.jpg
  10   Wed May 12 08:10:17 2021 LarsGeneralinstabilities 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. 
  17   Wed May 12 09:59:08 2021 BenediktGeneralRigol DSG821 signal generator settings
Attachment 1: CF7701F6-86BE-406C-8FAD-F3161463181C.jpeg
CF7701F6-86BE-406C-8FAD-F3161463181C.jpeg
  22   Wed May 12 18:59:15 2021 Ken UeberholzGeneralPower is back
Power is back and most things are running again
  23   Wed May 12 19:48:24 2021 SebastianGeneralDSG821 Network
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"
Attachment 1: IMG_20210512_195329_resized_20210512_075346417.jpg
IMG_20210512_195329_resized_20210512_075346417.jpg
  24   Wed May 12 22:28:55 2021 Ken UeberholzGeneralBunching succesfull
Bunching with 2 and 10 bunches succesfull
  25   Wed May 12 22:35:33 2021 DanyalGeneralfrev 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
  26   Wed May 12 22:48:25 2021 SebastianGeneralDSG 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
  27   Wed May 12 22:57:41 2021 SebastianGeneralLaser Reprate
laser reprate is seven times the revoolution frequency: 9.038283 MHz
pulse length: 735ps
  29   Wed May 12 23:45:23 2021 Ken UeberholzGeneralLaser 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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