PSB h- injection

1
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,

2
3 or 4 KSW bumpers?

• 27 m bump possible with both layouts (3 or 4
  KSW)

4KSW
3KSW
3
Effect of non-zero angle
4
Effect of x mismatch
Checked effects with simple linear tracking (no
space charge or non-linearities)
4 KSW x0
Foil 5.2 hits/p
3 KSW x?0
Foil 6.8 hits/p
Conclusion Keep KSW1L1 and a 4-bump!
5
Geometry
PSB/BI survey data
6
Geometry
159.06 mm
66 mrad
2410 mm
2564 mm
STARTPSB
7
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 27827x0.066) / (2x0.066) 1414
  mm
• and the BS bump amplitude by X_BS (1414 827)
  x 0.066
• X_BS 38.7 mm

8
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

9
Geometry
587
587
457
213
213
227
370
93.4
159.1
38.7
27.0
66 mrad
BS4
BS3
BS2
BS1
KSW1L1
387
387
113
113
257
127
200
200
200
200
400
70
2564
10
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

11
Lorenz stripping

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

12
Layout changes
13
New Layout
14
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?

15
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
16
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
200
237
113
50
100
17
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

18
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
19
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
20
Alternative dump location after BS4

• Dump would be outside PSB acceptance
• BS4 H aperture increases to about 180 mm
• Space available only 127 mmnot very feasible
• Dump would probably need to be included in BS4
  magnet

21
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.

22
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
23
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 (gt250
  pi.mm.mrad) when KSW is off

24
BS magnets

• Vertical gap by lt 4 m at all BS
• 100 p.mm.mrad vertical acceptance ? 44 mm gap
• Assume 46 mm gap to begin with

25
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 MMshould 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

26
TDR (!)