All quadrupole and dipole magnets at SIS and ESR are out of order. Repairs can be expected earliest tomorrow evening. No shifts will take place before 6pm. Have a look at your mails for details.

To realize the shortest bunches possible, we check the bunch length as a function of two different bunching amplitudes. With the bucket fill set to 1.0 we observe the spectra compiled in attachment 1. The second attachment is recorded with a bucket fill 0f 0.2.

For an RF amplitude of 0.2 we do not observe bunches any more but a coasting beam. In the shottky spectrum we can resolve a shift of the signal and thereby adjust the electron cooler voltage to the bunching frequency to within 1 V.

U_e-cooler = -104410 V
I_e-cooler = 80 mA

The HeNe was running over night and the measured laser frequency of the wavemeter was logged, see picture.
A significant drift of around 300 MHz is visible during the night.
It is possible, that the laser lab got too cold during the night, as the pulsed laser was not running.
For now, we put the wavemeter in a thermoinsulator box...

1.) If not already opened, open the Medusa Laser Control software, see picture:
2.) In the "view" submenu, choose "proteus status".
3.) At the bottom of the list, the K250 shows the scaled voltage.

If the laser controller is locked up again, the little display will show an error message after an attempted medusa scan.
To restart it, follow these steps:
1.) Unlock the beam stabilization.
2.) shut down medusa and the wavemeter software
3.) Turn off the 2 laser stages
4.) Close the shutter of the pumping laser
5.) Turn off and on the power button of the pulsed laser inside of the black box of the pump laser insertion.

To start again go back through the list.

It seems to be that there are some problems with the injections in the ESR.
The last 2 accumulation cycles showed that wheter only a small amount of ions are injected into the ESR or the injection is missing.

Photos of the last 2 accumulation cycles are attached.

We ask if there are some problems with the ESR or with the SIS18, because the particle number in the SIS18 is also decreasing... 

Thanks Jan!

yesterday (05.06.2024), firstly, the two ion pumps (underneath the fluorescence chamber) were switched off by the vacuum group (Björn Mai, Tel: 3438). Secondly, the two pressure gauges (located near the target) were switched off.  The pressure gauge at the fluo chamber is called E02VM3x and the pressure was 5.5e-11 mbar.  The other gauge is called IG2 and located further south, it measured 3.7e-11 mbar.  That was when ion pumps were still switched on.  Since ~10:45 (05.06.2024), the two ion pumps and the two ion gauges are switched off. There was no measurable change in the pressure after switching off the ion pumps.