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.

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

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)

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

The operators are still busy extracting the beam from the SIS18 towards the ESR and injecting it into the ESR. 

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 :( 

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. 

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. 

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. 

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

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. 

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 

The ions were changed to a different speed today at 2 PM. The new revolution frequency is now 1.291278 MHz.

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.

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".

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.