Dear all,

The test beamtime is now over. 
We had 6 days of Li-like carbon in the ESR (122 MeV/u). 
Effectively, we could measure almost 5 days continuously.  

There were only a few interruptions, one of which was a longer power failure. 
The vacuum in the ESR was not optimal, which strongly reduced the lifetime of the stored ion beam (~30 s) 
and the electron cooler showed weird instabilities, which need to be clarified still. 

Still, we were able to cover all aspects of the program. 
Essentially everything we tried worked. 

Therefore, I conclude that it was a great success. 

Many thanks to all who have contributed to it! 
Special thanks to Sebastian and Benedikt - who worked really hard during the last months - for prepapring the laser system and the data acquisition system. 
Also special thanks to Volker and Ken for preparing the XUV detector system. 

We will start sorting/ordering & filtering the data soon and will invite for a meeting where we present the raw data so that we can discuss it. 
Then we will also discuss the next big step: data analysis. 
Of course it is our next objective (with high priority) to publish the analyzed data in foreseeable time. 

I hope to see you soon. 
Until then, take care and stay healthy,

Danyal 

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

2VO: interlock, impossible to move (beam diagnostics is informed and will check)
1VO: +0.2mm --> half laser power, +1.2: laser gone (-1.0mm: also gone)

Ion beam adapted to measured laser beam, Target bump position: -22mm (was -18mm before)
Ion beam position verified with scrapers:
1HA: -1.0mm --> still there
2HA: +4.0mm --> beam gone
Target bump angle: unchanged (+1.2 mrad)

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

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.

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.

Power is back and most things are running again

Bunching with 2 and 10 bunches succesfull

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 

High rates on the detector at 50mm positions, laser does not seem to reach the exit window.

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
Manual laser scans with bunches: successful

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.
Once in this shift the Mesytek in the laser lab turned itself (?) off and the background rate increased. Hopefully this was a single event.

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. 

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).
It should take about 10 Minutes and might be already finished by now.

1.) so far: 
h = 2, 4, 6, 7, 8, 10, 12, 14, 16, 18, 20, 30
Amplitudes: (10, 50, 100, 150, 200, 250) mV

now we will try to use the laser-toy ;-)


> 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)
> 
> 2.1) Do we see the laser in the Schottky? (The laser has to be on the right side of the bunches and act as a barrier to damp the oscillation of the ions inside the buckets.) 
> If not change laser wavelength until we see the laser in the schottky 
> 
> 2.2) Do we see fluorescence in the XUV Detector signal? Weak fluorescence signal --> check laser-bunch timing by varying the lead delay until we see the highest fluorescence signal. 
> If we see no fluorescence signal change laser wavelength until we see fluorescence from the xuv anode signal.
> 
> 3.) Do we see that some sidebands vanish in the schottky? Does the lifetime of the ion beam increase?
> 3.1.) If not "play" with Laserparameters, scans, delays, etc...

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 :)

We shut the laser system down to prepare automated laser scans