EMMA Design Review 26th February 2007

Neil Bliss - Specification Update

Can there be a window between ERLP and EMMA? Check this action - we know that the emittance is increased, but what about the energy spread and bunch length.


Run ERLP at lower gradient? Need to run some S2E simulations with lower gradient. Check after Bruno's presentation.
People have been talking about 19 cavities rather than 21.
Geometry of magnets has been changed to make F and D parallel in each cell now.
F magnet translation has reduced substantially to only a few mm.
RF cavity length has been increased 105 to 110 mm to increase the shunt impedance.
Field clamp plates have been added to the engineering drawing.
Injection by Carol may be on inside of the ring. This raises the possibility of having the ring anticlockwise rather than clockwise.
Single girder option is being considered - arc sections would be machined and then linked together.
When the quadrupoles move, their fields will push on each other and therefore move the magnets slightly on their slides. This effect needs to be examined.

Scott Berg - Lattice Update

The lattice elements in one cell are now all co-parallel; a very small increase in apertures
Frequency range in cavities has to be increased to allow scanning over energy range.
The end field in the magnets causes a horizontal position shift at large apertures, which affects the required aperture (it jumps at the end of the magnets, when plotted longitudinally).
Energy spread/length in input bunch may affect the energy spread, and therefore dispersion, and therefore aperture, in the ring. Need to check the longitudinal emittance and give to Scott.
The FODO option is basically discounted.
The RF cavities are offset from the cell centre-line, at least in the model, by about 0.5mm.

Modelling requirements;
Stefan Tzenov will look at modelling ERLP injector at 10 MeV, and estimate the injection parameters. Injection phase may be random (no sync lock between RF systems) and then measured, or instead synchronisation can be attempted.
Ideal emittance is about 12 mm-mrad. See if 10 mm-mrad is possible from the injector.
Check slice energy spread, projected energy spread, bunch length, peak current and longitudinal emittance from ERLP at this energy.