Post date: Apr 3, 2014 7:44:48 AM
This morning we attempted to do more tune measurements at different energy, however we had some difficulty finding sidebands in the fft spectrum for the horizontal tune with perturbation when the energy was up to about 20MeV or more. We suspect that because the rigidity is higher the perturbation doesn't have such a big effect? We tried many things but couldn't see clear sidebands. Eventually we had to give up on the tune measurement as it would have required installing the horizontal pertubator & opening vacuum of the main ring (a few hours work + overnight...)
The ion source is still troublesome and the driving current has been turned up again...
After ending the tune measurement we then made a plan to attempt an emittance growth measurement as this was felt to be a) easier and b) more informative than just the energy loss measurement. First we needed to match the horizontal orbit in order to make sure any observed growth is due to emittance and not betatron oscillations around the closed orbit.
This was one of the original experimental topics and may take some time so we will concentrate on this for the afternoon instead of putting in the slit. This means the dispersion matching will not be able to happen this week - we decided to prioritise the Emittance growth measurement as this needs validating against simulation. Suzie has suggested also matching at the higher corrector setting of 700A as this may improve operation generally if the COD is reduced.
We also want to make an energy loss measurement. We will see how we go with the emittance growth measurement tomorrow morning & orbit matching tonight.
Update 9:22pm (Japanese time) Suzie added her results from the k value calculation with gamma value calculated from Energy in the rf pattern file.