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.

https://tu-darmstadt.zoom.us/j/4948400422?pwd=SEJaUzBuYXM0TTd6UWxoZTFlWEZxUT09

Meeting ID: 494 840 0422
Passcode:  215586

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)).

Old parameters: OffsetM Ax 0.00; Bx 0.00; Ay -0.08; By -0.40
New parameters: OffsetM Ax 0.00; Bx 0.35; Ay -0.08; By -0.40

Optimizing the laser bunch timing.
h = 7 (9.0389145 MHz)
Reprate is already set to same frequency.


Results: For h=7:
4 ns delay results in a maximum fluorescence rate in the XUV detector
25 ns delay shows the highest intensity in the Schottky spectrum while the laser operates at 1028.940 nm.

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)

We are now testing these scan functions with coasting beams; ecooler 10 mA.

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.