The purpose of the tool was to develop a method to change the master oscillator (MO) radio frequency (RF) for the MAX IV 3 GeV and 1.5 GeV storage rings without affecting the orbit stability.

1. Select which storage ring to change the MO RF for.
2. Check the current MO RF value.
3. Select the desired change to the MO RF.
4. Press Move RF to perform the "sweep".

Changing the RF of the MO was done during beam delivery to beamlines in order to maintain a stable beam condition (keep the beam energy spread and horizontal and vertical beam emittance at acceptable levels). Beam instabilities can arise due to e.g. beam modes increasing and being enhanced in RF cavities or due to changing the gap height or phase of an insertion device.

In order to get rid of the unwanted increased beam modes, the ring RF was changed. It cannot, however, be changed too much as a storage ring's orbit feedback system cannot handle instantaneous changes instantly. Instead, the MO RF has to be changed in small steps which are invisible to beam instability-sensitive beamlines. Between each step, the orbit feedback system corrects the beam.

The MO RF corrects the beam in small "invisible" steps and the storage ring's orbit feedback system corrects for the changes in the MO RF, resulting in that the beam instabilities originating from the MO RF adjustments are as small as the regular beam oscillations.

The tool is useful for changing the MO RF of a MAX IV storage ring while not affecting beam stability as recorded by beam instability-sensitive beamlines.