PSB h- injection

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# PSB h- injection - PowerPoint PPT Presentation

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

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Presentation Transcript
PSB h- injection
• Layout issues
• Are 3 or 4 KSW needed
• Geometry of the injection
• Element lengths and locations
• Element performance specifications
• H0 / 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)

4KSW

3KSW

Effect of x’ mismatch

Checked effects with simple linear tracking (no space charge or non-linearities)

4 KSW: x’=0

Foil:

5.2 hits/p+

3 KSW: x’0

Foil:

6.8 hits/p+

Conclusion: Keep KSW1L1 and a 4-bump!

Geometry

PSB/BI survey data

Geometry

159.06 mm

2410 mm

2564 mm

\$STARTPSB

Geometry

Geometry of the line gives

X_BI = 159.1 – 0.066 x S

Fixing S location of BS1 at 0.827 m, and adding 27.0 mm KSW bump

X_BS_KSW = (S – 827) x 0.066 + 27.00

Then SBS2 is given when X_BI = X_BS_KSW:

159.1 – 0.066 SBS2 = 0.066 (SBS2 – 827) + 27

so finally the BS2 position is given by:

SBS2 = (159.1 – 27+827x0.066) / (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

587

587

457

227

213

213

370

93.4

159.1

38.7

27.0

BS4

BS3

BS2

BS1

KSW1L1

127

387

113

113

387

257

200

200

200

200

400

70

2564

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  Br = 1.903 T.m.  0.126 T.m.  0.63 T.
• Foil holder / changer
• In a module which is about 176 mm long, including flanges…
• H0/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
KSW fall times
• Assume injection over 10 – 100 turns
• KSW fall time should be variable between 10 and 100 ms
• 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 30-40 ms could still be fine – tbc for LHC filling and with ACCSIM if possible

BS at 100%

BS at 50%

H0/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

587

213

15.6

BS4

BS3

200

50

100

237

200

113

Aperture and envelopes
• Assume 0.43 mm.mrad ex normalised for injected beam
• ±4 sigma betatron envelopes plotted
• Have to think about Dx  2 m means about 2 mm Dx for Dp 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.

17 mm

30 mm

17 mm

Aperture and envelopes
• Second area of concern – internal dump
• Need to position this to catch unstripped H0
• 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 2nd 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 = 15-16 m depending on tuneAv = 100pi mm mrad

A/Ah: H

BS1

BS4

A/Av: V

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 – by < 4 m at all BS
• 100 p.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)
• 10-100 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 p 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