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  Laser Cooling Experiment 2021, all entries  Not logged in ELOG logo
Entry  Tue May 31 07:29:11 2022, Ken, Detectors, XUV-Detektor 
Rate was very low: ~ 100Hz
Adjusted Walk level and Threshold, new rate: 5kHz
Additionally, parameters of the detector were varied for optimization but were returned to default afterwards.
Entry  Mon May 17 21:43:56 2021, Danyal, General, The test beamtime was a success. 
Dear all,

The test beamtime is now over. 
Entry  Mon May 17 08:05:42 2021, Team, General, End of beamtime 
~ 8 a.m.
Entry  Sun May 16 22:11:49 2021, Team, General, Laser Polarisation values 
maximal transmission of PBSC (257/514 pbsc was used in combination with xlp12 detector and visual on a screen):

L/4 @ 276° & L/2 @ 348°                -->   p-polarized light
Entry  Sun May 16 21:23:02 2021, Team, General, ESR OPEN -> preparation for Polarisation Tests 
 
Entry  Sun May 16 11:29:22 2021, Benedikt, General, Automated laser scans working 
The automated laser scans are working now.
We can now scan with the following functions: triangle, sawtooth, cosinus/sinus, arctan, min (linear scan, than stands still)
Entry  Sun May 16 07:18:56 2021, Night Shift Sebastian/Max/Noah, General, Preparation for automated laser scans 
We shut the laser system down to prepare automated laser scans
Entry  Sun May 16 07:03:07 2021, Team, General, Laser cooling with 166ps 
We saw some indications of laser cooling @ 166ps pulse length
Entry  Sun May 16 06:13:46 2021, Team, General, Switch to 166ps  
 
Entry  Sun May 16 05:24:00 2021, Team, General, Laser cooling with 285ps 
we also see laser cooling with 285ps pulse length
Entry  Sun May 16 05:09:27 2021, Team, General, Switch to 285ps 
pulse length -> 285ps

minimum 62mW inside ESR (depending on laser wavelength)
Entry  Sun May 16 05:09:04 2021, Team, General, Laser cooling with 482ps 
we see laser cooling with 482ps pulse length
Entry  Sun May 16 02:28:21 2021, Team, General, #Beam ON! 
Laser specs:
pulse length -> 482ps
Entry  Sun May 16 02:22:19 2021, Sebastian, General, "Der Laser ist ok" 
 
Entry  Sun May 16 02:20:58 2021, Sebastian, General, "Der Laser ist (wieder) ok" 
 
Entry  Sun May 16 02:18:53 2021, Sebastian, General, UV Drop 
1:25 a.m. huge drop in UV laser power
-> small crystal bump with both y screws of bbo oven
Entry  Sat May 15 12:11:54 2021, Benedikt, General, Laser-bunch-timing 
Optimizing the laser bunch timing.
h = 7 (9.0389145 MHz)
Reprate is already set to same frequency.
Entry  Sat May 15 11:26:44 2021, Benedikt, General, TEM parameters 
We changed the horizontal position of the laser beam a bit, so that we maximized the fluorescence signal on the XUV detector (coasting beam, scanning laser
(0.03 Hz)).
Entry  Sat May 15 11:06:31 2021, Benedikt, General, New Zoom link for the moment 
https://tu-darmstadt.zoom.us/j/4948400422?pwd=SEJaUzBuYXM0TTd6UWxoZTFlWEZxUT09

Meeting ID: 494 840 0422
Entry  Sat May 15 09:57:24 2021, Dayshift, Runs, Currently on schedule  
Enhance fluorescence rate and perform 
laser bunch timing 
Entry  Sat May 15 09:50:31 2021, Team, Runs, Laser cooling of....  
H=2
H=7
H=10
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
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.
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
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
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
Entry  Fri May 14 06:34:45 2021, Team #Night, Analysis, DSG821 IP 
140.181.104.108
Entry  Fri May 14 04:50:46 2021, Team #Night, General, Scraper Tests Ion / Laser Beam 
laser is 4-6mm below the ion beam.
It could be that the interaction between both beams came only from the interaction between the laser halo with the ion beam ?!
Entry  Fri May 14 01:34:44 2021, Team, General, strange XUV Anode signal Screenshot_(68).png
We see a strange behavior of the anode signal when we bunch the ion beam and electron cooler is on.

peak structure... ---> we play now with the bunching amplitude 
Entry  Fri May 14 01:28:04 2021, Sebastian, General, "new" laser wavelength 
Minor changes in electron cooler voltage (~+13V, now 66903V measured by DMM) leads to that we had to shift the laser wavelength to:

1028,965nm 
Entry  Thu May 13 23:42:37 2021, Ken Ueberholz, General, What was done Schottky1.jpegSchottky2.jpegSchottky3.jpegSchottky4.jpeg
In this shift a number of successful Schottky measurements were done:
With fixed laser wavelength, while varying the wavelength, with different bunching and more (see logfile 1 for more info: line 53 to at least 107).
The detector software sometimes files to change the current of the power supplies, if this happens a simple restart of the GUI fixes the problem.
Entry  Thu May 13 21:00:48 2021, Benedikt, General, New reprate of the UV laser 
The lasersystem now operates at a reparte of 9.038946 MHz. This is 7 times f_rev (see previous post).

In the future, the laser-bunch-timing can be adjusted.
Entry  Thu May 13 20:18:10 2021, Benedikt, General, New f_rev 
The ions were changed to a different speed today at 2 PM. The new revolution frequency is now 1.291278 MHz.
Entry  Thu May 13 18:34:54 2021, Ken Ueberholz, General, What happened scince shift change at 4pm 
Ion frequency shifts with laser, both manually and scanned, without bunches: successful
Bunching with 7 and 20 bunches: successful
Tried laser scans with bunches: unsuccessful
Entry  Thu May 13 01:21:30 2021, Sebastian, General, Current schedule ... so far 
1.) check h=2,4,6,7,8,10 .... bunching frequencies with different amplitudes (signalgenerator), Ecooler ON, Laser OFF --> record schottky and "normal" DAQ

2.) Ecooler ON, Bunching ON, Laser ON (wavelength fixed and/or scanned)
    Reply  Thu May 13 03:35:25 2021, Lars, General, Status: Current schedule ... so far 
1.) so far: 
h = 2, 4, 6, 7, 8, 10, 12, 14, 16, 18, 20, 30
Amplitudes: (10, 50, 100, 150, 200, 250) mV
Entry  Thu May 13 02:45:29 2021, Sebastian, Analysis, ESR pressure 8x
 
Entry  Thu May 13 02:42:58 2021, Sebastian, General, Lasershutter ESR Entrance?! IMG_20210513_020027_resized_20210513_024049198.jpg
attached should be the name of the entrance laser shutter. just in case somebody will close it ;)
Entry  Thu May 13 01:55:15 2021, Sebastian, General, ESR amplifier reset / laser check IMG_20210513_014345_resized_20210513_015540959.jpgIMG_20210513_014353_resized_20210513_015541291.jpg
we had to go into the ESR because the amplifiers hooked up. both amplifiers were resetted!

we also checked why we didnt see the laser at the exit window.
Entry  Thu May 13 01:13:06 2021, Sebastian, General, Bunching frequencies 
relating to Danyals ID 25 post are the current bunching frequencies:

h=2      -->     2,5823668 MHz
Entry  Thu May 13 01:05:45 2021, Danyal, DAQ, more stability by bunching 
Because the C3+ part of the ion beam is properly bunched, it is no longer so sensitive to the drifts caused by the e-cooler. 
In the O4+ part of the ion beam these drifts can still be seen. 
Entry  Thu May 13 01:01:27 2021, Danyal, DAQ, bunched ion beam bunched_-_signal.jpgbunched_-_Schottky.jpgzoom_bunched_-_Schottky.jpg
 
Entry  Thu May 13 00:58:53 2021, Danyal, DAQ, unbunched ion beam not_bunched_-_signal.jpgnot_bunched_-_Schottky.jpg
 
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.
Entry  Wed May 12 23:36:18 2021, Ken Ueberholz, DAQ, VI change 
carbon main vi - kopie is now in operation

here, in keysight.vi the input settings for the new impedence for the multimeter are now hopefully correct --> THIS SHOULD BE CHECKED IF THE RING IS OPEN
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 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
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
Entry  Wed May 12 22:28:55 2021, Ken Ueberholz, General, Bunching succesfull 
Bunching with 2 and 10 bunches succesfull
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
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 15:36:04 2021, Danyal, Accelerator, general power failure in ESR! (everything is off) 
The power in the ESR is off. 
(also on the gas-target area on top of ESR)
Electrical engineers are trying to find and fix the problem. 
Entry  Wed May 12 13:11:58 2021, Danyal, Accelerator, short break between 13:30 and 15:30 
There will be a short break (2 hours) this afternoon. Between 13:30 and 15:30. 
The so-calles "super lense" in the UNILAC needs to be cleaned (rinsed). 
After that operation should continue as usual. 
Entry  Wed May 12 10:15:47 2021, Volker Hannen, DAQ, Unplugged TDC inputs for MCP front and back 
To reduce the load on the VUPROM TDC, we unplugged the TDC inputs for the front and back signals of the MCP of the XUV detector.
The Anode signal is still plugged in and should be sufficient for the analysis.
Entry  Wed May 12 10:14:18 2021, Lars, Accelerator, E-Cooler 
M.Steck et al. discussed about the E-Cooler and found a possible issue. They asked for enterance to the ESR. Since nobody else was in the HKR and anyway
nothing was running because of some other issues, I told, the experiment would not be disturbed and they could enter and do things. (Sth. like putting
some repeller electrodes onto hand and other magical things).
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 09:09:15 2021, Sebastian, DAQ, Fluorescence 1029967nm.png
fluorescence with detector in parking position
fixed laser wavelength
electron cooling ON, 
Entry  Wed May 12 09:05:48 2021, Keysight Settings, DAQ,  
 
Entry  Wed May 12 09:04:48 2021, Sebastian, DAQ, Keysight AUtoCal IMG_20210510_143940_resized_20210512_090353546.jpg
 
Entry  Wed May 12 08:42:49 2021, Sebastian, Analysis, Laser scans / coastig beam / no ecooler Screenshot_(156).png
Attached you'll see a first laser scan of ~100GHz in the UV.
Entry  Wed May 12 08:41:36 2021, Sebastian, Analysis, Laser stability 
During night shift the laser was very stable! Only minor fluctuations occured in the UV
Entry  Wed May 12 08:32:04 2021, Sebastian, Analysis, fluorescence & energetic overlap Screenshot_(154).png
During the night shift we saw several rises of the fluorescence (see another entry) and also energetic overlap in coasting beam modus.
Here the laser wavelength was stabilized @ 1028,967nm and electron cooler was switched off because of some fluctuations which we saw in the schottky.
Left part of the schottky picture shows the c3+ beam, the right part is the o4+ contamination.
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.
Entry  Wed May 12 02:16:25 2021, Danyal, Lars, Accelerator, Ion beam position 
Laser Position with scrapers verified. 
1HA: impossible to scratch laser beam, still there at -1.0 mm
2HA: +3mm --> half the laser power on detector; +4.5mm --> gone
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.
Entry  Tue May 11 18:29:35 2021, Danyal, General, first ions in the ESR first_ions_are_injected.jpg
 
Entry  Tue May 11 16:33:31 2021, Ken Ueberholz, Detectors, Detector control manual Manual.pdf
Attached to this elog entry is a short manual for the xuv-detector control. If anything is missing or not understandable I can change anything.
Entry  Tue May 11 16:07:59 2021, Sebastian, DAQ, DAQ Manual DAQ_Manual.pdf
Attached you'll find a short manual for operating the whole DAQ system
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  Mon May 10 07:58:13 2021, Danyal, General, Telephone numbers and Zoom link 
Telephone numbers:

ESR laser lab: +49 (0)6159 71 - 2882
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