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

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

Constraints for foil stripping Deliberate mismatch between inj/ring optics Minimum β i given by foil heating – was 10 m for PS2 – probably higher for HPPS  to be studied – the optimum mismatch assuming β i =10m results in: β r =~ 32 m β i / β r – Smaller ratio helps to reduce foil hits but increases foil temperature  trade-off α i = α r = 0

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

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 ε rms – Paint to geometric emittance of 15 um (78um/5.17 ) for full beam Analytical painting calculation – space charge not included 600 turns Q x of xx.41, β x,y ~ 20m, α x,y ~ 0 – Tune at injection? – β x,y in 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

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

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 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

Extraction kicker system 50 GeV75 GeV Deflection anglemrad2.1 BrhoTm B.dlmT.m VoltagekV6060 (56.7) ImpedanceOhm12.5 Rise timens Length per magnetm # magnets69 Magnetic/total lengthm10.6/ /21 BmT36 Gap/widthmm90/120 InductanceuF3.03.1

Extraction septum 50 GeV75 GeV Deflection anglemrad52 BrhoTm B.dlT.m Septum thicknessmm55 BT11 Gap heightmm34 CurrentkA27 Magnetic/total lengthm8.8/ /16.7 Could be reduced due to smaller beam size at 75 GeV

Next steps Injection – Foil heating  minimum β i – 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