PSB h- injection Layout issues –Are 3 or 4 KSW needed –Geometry of the injection –Element lengths and locations Element performance specifications H 0 / H - dump Beam envelopes and apertures Summary of main points Based on existing work and input from Wim, Michel M., O.Berrig, Klaus, Frank, Giulia, …

3 or 4 KSW bumpers? 27 m bump : possible with both layouts (3 or 4 KSW) 4KSW3KSW

Effect of non-zero angle

Effect of x’ mismatch Checked effects with simple linear tracking (no space charge or non-linearities) 4 KSW: x’=0 3 KSW: x’  0 Foil: 5.2 hits/p+ Foil: 6.8 hits/p+ Conclusion: Keep KSW1L1 and a 4-bump!

Geometry PSB/BI survey data

2564 mm 2410 mm 66 mrad $STARTPSB mm Geometry

Geometry of the line gives X_BI = – x S Fixing S location of BS1 at m, and adding 27.0 mm KSW bump X_BS_KSW = (S – 827) x Then S BS2 is given when X_BI = X_BS_KSW: – S BS2 = (S BS2 – 827) + 27 so finally the BS2 position is given by: S BS2 = (159.1 – x0.066) / (2x0.066) = 1414 mm and the BS bump amplitude by X_BS = (1414 – 827) x 0.066: X_BS = 38.7 mm the injected beam position at the foil is X_BS_KSW = 65.7 mm Geometry

Implications for present elements –Move KSW1L1 upstream by ~170 mm –No space for BI3.MSF10HV –No space for present vacuum pumping (valve?) presently at B1

Geometry 2564 BS4BS3 BS2BS1KSW1L mrad

Element lengths and strengths KSW –Essentially the same B.dl as present – no issue BS magnets –200 mm magnetic –250 mm vacuum length in layout –At 160 MeV  B  = T.m.  T.m.  0.63 T. Foil holder / changer –In a module which is about 176 mm long, including flanges… H 0 /H - dump –In a module which is about 150 mm long including flanges –Internal! Other new injection BI (WS/BTV) –In modules about 187 mm long including flanges

Lorenz stripping Should not be an issue for 160 MeV even at 0.63 T

Layout changes

New Layout

KSW fall times Assume injection over 10 – 100 turns –KSW fall time should be variable between 10 and 100  s –Reasonably linear (guess at ~few % tolerance – tbc) –To be checked – can we go to 30 us fall time – LHC injection OK?

BS fall times BS can be more relaxed than KSW –Fall time affects only p+ foil hits – –Checked dependency with linear tracking shows  s could still be fine – tbc for LHC filling and with ACCSIM if possible BS at 50% BS at 100%

H 0 /H - beam dump Assume that this has to be internal –100 mm length – tbc that this is OK for 160 MeV –150 mm space in the layout before BS4 BS4BS

Aperture and envelopes Assume 0.43 mm.mrad  x normalised for injected beam ±4 sigma betatron envelopes plotted Have to think about D x  2 m means about 2 mm  x for  p of 0.001

Aperture and envelopes First area of concern – BS1 exit –Looks like a septum – in vaccuum? –Total width 30 mm? gives 17 mm to axis of injected / circulating beam –Technical feasibility to be examined –Aperture to be carefully checked – inside PSB acceptance with BS on. 30 mm 17 mm

Aperture and envelopes Second area of concern – internal dump –Need to position this to catch unstripped H 0 –In present layout upstream edge only 15 mm from injected beam axis –Effect of the injection mismatch also to be included – effectively increases the emittance (although probably OK due to KSW falling) –Will be difficult to accommodate dump elsewhere…. 15 mm

Alternative dump location: after BS4 Dump would be outside PSB acceptance BS4 H aperture increases to about 180 mm Space ‘available’ only 127 mm…not very feasible –Dump would probably need to be included in BS4 magnet…

External dump ? Not possible with present injection geometry –Asymmetry wrt centre of L1 means no possibility to add 2 nd foil to strip remaining ions, and to extract resulting p+ via or past BS4. Only hope for external dump could be to increase angle of B1 line to ~100 mrad and to reduce the distance between BS1-2 and BS3-4 magnets to about 300 mm –would require several difficult changes to proposed version: reduces space for H- holder/handler to ~60 mm requires completely new geometry & layout of incoming B1 line requires stronger BS magnets, with about 1 T field needs another foil holder/handler unit needs BS4 magnet to be built as an extraction septum Presently not under consideration.

Aperture c.f. PSB aperture The aperture limit in the PSB is the "beamscope window", located in section 8 between F and D quadrupole. It's used for transverse emittance measurement via shaving of the beam. –Full aperture is 70 x 80 mm2 (hxv) –Beta h = 5-6 m depending on tune: Ah = 250pi mm mrad –Beta v = m depending on tuneAv = 100pi mm mrad A/Ah: H A/Av: V BS4 BS1

Aperture c.f. PSB aperture H acceptance as a function of bump amplitude –~120 pi.mm.mrad with KSW and BS on (start injection) – limit at BS1 “septum”. –Increases to above full acceptance (>250 pi.mm.mrad) when KSW is off

BS magnets Vertical gap –  y < 4 m at all BS –100 .mm.mrad vertical acceptance  44 mm gap –Assume 46 mm gap to begin with

Summary H- injection layout in L1 looks feasible after first iteration Several issues still to be checked/solved, including: –Aperture at BS1 exit for circ. Beam – tracking –Aperture at BS3 internal dump for circ. Beam – tracking –Check of BS fall time dependence for LHC & with ACCSIM –Feasibility of 200 mm long, 0.63 T BS magnets (and “septum” BS1) – us KSW fall time: HW feasibility and parameter space coverage –Vertical painting….not included by MM…should this be considered (need about 4 mrad at injection point or  upstream). –Internal dump concept – material, length, cooling, handling, … –Foil manipulation mechanism in 226 mm available… –BI between BS1-2 and BS2-3 (337/187 mm available) –Removal of vacuum manifold at end of L1

TDR (!)