8:40 Start warming up, problem with PSS. It was restarted.

Problems to start and tune the RF cavity. A clear working procedure and reliable tuning should b defined to optimize the Ring comissioning progress.

Feedback for teh RF has the suspicious behavior. At motor position close to the nominal, the feedback ofsets the motor in the negative direction for 100k steps and then, comes back from negative to the requested position.

Sometimes the we lost the power in the RF cavity.

Start of the ring. RF power is ~10-30 kV and freq = 500.0202 MHz. We loaded the machine with the yesterday's setting.  Optimizattion of the storage and orbit/tune. No stored beam achived. Only a few tens of turns achieved.

We decided to ramp the RF frequency up to 100 kV. We could not tune the RF cqvity to our previous value 500.41. We found the plunger position only for 500.38 MHz, so we started to work on this frequency.

After optimization work, we have achieved the storage (see the figs attached) with a reasonable orbit.

By setting the sextupoles and optimizing the quadrupoles we achived to have the kind of clean storage, stable orbit. 

By injector optimization we reduced the betattron oscilation at the injection. From time to time, the RF section phase ans power should be corrected. The further orbit correction should be done.

The estimated tunes are  (~0.19, ~0.66).

Then, we started to go back to the nominam RF freauency 500.0202 MHz.

Tuning of the cavity. Power is 40 kV.

The difference in orbit is attached in the scrennshot. Then, after the optimization it was almost the same as this morning.

By calculating the FFT on the mixed signal with the scope (see screenshot), we found the following frequency 16.68*30 = 500.4 MHz.

Without RF power, it was not possible to measure the revolution frequency as the FFT had two-peak strucutes, which is complicated to interpratate/understand.

At the nominal frequency, no storage is achieved. We wants to measure the revolution frequency operating at 500.4 MHz. Start of the ramping the power at this frequency. Big problem to tune the RF cavity. We can not inject the power in the cavity.

=> The clear observation that the ring is more stable and the storage is possible with the frequency around 500.4 MHz. it means that the circumference normally is shorter by ~ 10 mm. Investigations arer ongoing.