Post date: Jun 24, 2014 4:07:00 AM
Suzie has arrived at KURRI this morning. We had a morning meeting to discuss current status & plans.
Machine status:
Horizontal perturbator is installed
There is a slit in the injection line
Small faraday cup (Kuriyama-san) in injection foil region
The three main experiments planned for Suzie's visit are the dispersion control/matching, energy loss on the foil and tune measurement with energy. We will think in more detail about further measurements later during the visit - after we establish if new bits of diagnostic etc are working.
Tune measurement:
Ishi-san reported that the new triangle plate monitor (photos attached) by Sakamoto-san had been installed and tested with the horizontal perturbator. The signal from the monitor can be seen but because it is quite large (vertically) the coherent oscillations could not be observed. The plan is to reduce it's size vertically (it had been made large to avoid causing beam loss, but actually there are other items in the ring which have a smaller vertical aperture already). This should be done in a few days, so we will do the tune measurements after this is ready.
Dispersion control & matching:
Ludovic has written a code to study the control of dispersion using injection line quadrupoles. (Mainly Q6, Q7, Q8) He mentioned that Q8 seems to be the main 'knob' to control dispersion.
Ishi-san discussed a method to measure D, D' (will attach slides) by:
- select for momentum using slit in the injection line (up to perhaps 0.5% or 1% momentum variation?)
- use the small faraday cup at the injection foil region to measure delta x (see image)
- assuming a phase advance (from model) between foil and S3, then measure delta x' to get D'
- note that this depends on matching, the result might indicate if there is a large modulation of D from mismatch
Suzie suggested that to start with we use Shinji's equivalent momentum method to take at least 2 or 3 comparable measurements to the March/April one with different Q8 strength. Then we can attempt the new method as well. Ludovic may also be able to do more measurements & extend the method after Suzie's visit.
Energy loss on foil:
We quickly discussed the current status of the energy loss analysis from Chris R and the need for more data at high voltage. Uesugi-san said he had also tried an analysis and had similar results to Chris (ie. cannot yet see the energy loss reliably).
This is the most straightforward measurement of the three so we will start with this during this afternoon.