HP-PS injection and extraction status

1. HP-PS injection and extraction status W. Bartmann, B. Goddard HP-PS meeting, 20-November 2013

2. TODOs • H- injection • Constraints for foil and laser stripping • Distribution after painting for collimation • Painting function  foil heating • Extraction equipment for 50 and 75 GeV • Apertures of LSS quads • Minimum length of “side” drifts in LSS • Optimize phase advance between kicker and septa • Apertures, lengths, material of extraction equipment for impedance

3. Constraints for foil stripping • Deliberate mismatch between inj/ring optics • Minimum βi given by foil heating • was 10 m for PS2 • probably higher for HPPS  to be studied • the optimum mismatch assuming βi =10m results in: βr=~ 32 m • βi /βr • Smaller ratio helps to reduce foil hits but increases foil temperature  trade-off • αi = αr = 0

4. Constraints for laser stripping • Laser peak power is proportional to vertical injected beam size if the beam-laser interaction is horizontal • Minimize as much as possible vertical beam size in IR • Assumed 7 m bety at waist for PS2 • Longitudinal painting: • large momentum range increases tremendously the required laser power • Bunch length: • increases laser average power • Energy jitter: • increases frequencies to be swept • should be an order of magnitude lower than initial dp/p • Trajectory jitter

5. Injection painting • Injected transverse emittance of 0.4 um (1 sigma rms normalised) • Want to transversely paint to about 13 um (1 sigma rms normalised) • Since the resulting distribution is more uniform than Gaussian compare percentage of beam • Gaussian distribution: 95% of beam in 6 εrms • Paint to geometric emittance of 15 um (78um/5.17 ) for full beam • Analytical painting calculation – space charge not included • 600 turns • Qx of xx.41, βx,y~ 20m, αx,y~ 0 • Tune at injection? • βx,yin ring to be updated with optimum mismatch values of > 30 m • Assume • n(x,x’,y,y’) = n(x,x’) n(y,y’) • Change in painting amplitude is slow wrt betatron oscillation

6. Phase space distribution after painting SC will further smear out the distribution  aim at slightly smaller value of target emittancethan 15 um full geometric

7. Painting function • Correlated or anti-correlated painting: • Uniformity: no KV distribution for correlated painting • Higher number of foil hits for anti-correlated painting • Also differences in coupling, aperture, halo to be taken into account •  to be studied

8. Extraction kicker system

9. Extraction septum Could be reduced due to smaller beam size at 75 GeV

10. Next steps • Injection • Foil heating  minimum βi • Iterate painting for new optics parameters • Add space charge • Extraction • Calculate required kick strength for kicker and septum • Minimum beam separation at septum 5 sigma between injected circulating and extracted • New optics, quad width • Iterate HW characteristics • Apertures of LSS quads