Speaker: Chris Rogers
Abstract: Injection into FFAs has been performed in the past by single turn kickers and charge exchange injection. In this paper injection into a vertical FFA is considered using a painting scheme using charge exchange and a system of pulsed magnets. Both horizontal and vertical magnets are required to manage coupled optics. Due to the short drift length, a multi-cell scheme is considered. The challenges inherent in such a scheme will be discussed.
5 replies on “Injection into a vFFA”
The beam is moved downwards to avoid the foil, but the acceleration will move the beam upwards. I’m guessing there is also a horizontal displacement (and the foil is a corner shape) so that when acceleration begins, the beam does not hit the foil?
In fact, the plan is to inject at the top of the magnet and move down as we accelerate (so field gradient m is negative). This is simply so the foil hangs down on its holder.
It appears that you’re creating a pretty non-uniform distribution in phase space because the fractional tunes are nearly m/5,n/3. I would think that a more uniform density would be preferable; is it possible to move further from those rational tunes to get a more uniform filling? Or is there a reason you need to be near those rational tunes?
Along the same lines could you do a rastering in the u-v amplitude space to get a more uniform phase space fill, and is that even desirable?
At the moment I move along line of constant phase and increase the amplitude. I would like to investigate changing phase – I just haven’t looked at it yet. I think it would probably fill the phase space more smoothly, which is usually a good thing to do. It isn’t my biggest worry at the moment though.