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 non-zero angleStart of painting processwith x’ = 0

x

x’

End of painting processwith x’ 0

x

x’

Effect of x’ mismatchChecked 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

2070

2080

2090

2100

2110

2120

2130

1830 1840 1850 1860 1870 1880 1890 1900

2108.5

2109.0

2109.5

2110.0

2110.5

2111.0

2111.5

1878.0 1878.5 1879.0 1879.5 1880.0 1880.5 1881.0

(1879.591,2110.621)

PSB/BI survey data

2564 mm

2410 mm

66 mrad

$STARTPSB

159.06 mm

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

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

BS4 BS3 BS2 BS1 KSW1L1

200 200 200 200 400387 387113 113

70

257127

159.

1

27.0

38.7

93.4

66 mrad

587587213 213227 370

457

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 = 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

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 30-40 s could still be fine – tbc for LHC filling and with ACCSIM if possible

BS at 50%

3.0

3.2

3.4

3.6

3.8

4.0

4.2

4.4

4.6

4.8

5.0

1 10 100 1000BS fall time [us]

Foil

hits

/ p+BS at 100%

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

BS4 BS3

200 200237 11350

587 213

100

15.6

Aperture and envelopes• Assume 0.43 mm.mrad x normalised for injected beam

• ±4 sigma betatron envelopes plotted

• Have to think about Dx 2 m means about 2 mm x for p of 0.001

-0.10

-0.05

0.00

0.05

0.10

0.15

3.804.004.204.404.604.805.005.205.405.605.80

S [m]

x [m

m]

BS1BS2BS4

Dump

BS3

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

3.803.853.903.954.004.054.104.154.20

S [m]

x [m

m]

BS1

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

17 mm

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

5.205.255.305.355.405.455.505.555.60

S [m]

x [m

m]

DUMP

BS4

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…

-0.10

-0.05

0.00

0.05

0.10

0.15

3.804.004.204.404.604.805.005.205.405.605.806.00

S [m]

x [m

m]

BS1BS2BS4 BS3

Dump

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

0.8

1

1.2

1.4

1.6

1.8

2

020406080100120140160

0.8

1

1.2

1.4

1.6

1.8

2

020406080100120140160

A/Ah: H

A/Av: V

0.8

1

1.2

1.4

1.6

1.8

2

12345678

BS4BS1

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

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2.00

2.25

2.50

2.75

3.00

0123456789101112S [m]

Ax/

Ah

No bump

KSW and BS

BS only

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

V_gap H_gap mag length B.dl B vac length septum width[mm] [mm] [mm] [Tm] [T] [mm] [mm]

BS1 44 110 200 0.126 0.63 250 30BS2 44 160 200 0.126 0.63 250BS3 44 160 200 0.126 0.63 250BS4 44 120/180 200 0.126 0.63 250

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 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 (!)