LINAC4 ADVISORY COMMITTEE

Booster Injection ModificationWim Weterings AB/BT

With input from

B. Balhan, J. Borburgh, T. Fowler, B.Goddard, M. Hourican, L. Sermeus

and many others

29-01-2008

29-01-2008 W. Weterings - LINAC4 Advisory Committee 2

Booster Injection Principle Beam Distribution LINAC4 Pulse Structure Beam Separation

H- charge-exchange Injection System Principle Foil Heating

Layout and Available Space Required Modifications Main Design Parameters Present Status Conclusion

Talk Overview

29-01-2008 W. Weterings - LINAC4 Advisory Committee 3

Vertical Septum BI.SMV & BI.BVTBeam slices are further deflected

by the BI.SMV septa into the BI.BVT vertical dipole apertures to achieve the required booster beam

level separation of 360 mm between each ring

Booster Injection Principle

Proton Distributor BI.DISsystem of pulsed

magnets, which kick slices of the beam to

different vertical positions at the vertical septum

BI.SMV

H- Charge-Exchange Injection System

160 MeV H- beamfrom LINAC4 is injected

through a graphite stripping foil to convert ~98% of the beam to protons, using two independent closed orbit

bump systems

29-01-2008 W. Weterings - LINAC4 Advisory Committee 4

Booster Injection Principle

4 = 360 mm

BI.DIS BI.SMV BI.BVT

3 = 0 mm

2 = -360 mm

1 = -720 mm

BI.

DV

T30

BI.

QN

O30

BI.

QN

O40

BI.

DV

T40

PSB

29-01-2008 W. Weterings - LINAC4 Advisory Committee 5

Booster Injection Principle Beam Distribution

Proton Distributor BI.DIS

Deflection [mrad]

-40

-30

-20

-10

0

10

20

51000 52000 53000 54000 55000 56000 57000 58000Ape

rtru

re [m

m]

Beam offset7.

27

-3.6

5

-3.4

9

-3.4

2

-3.6

2

-3.8

8

0 mrad → ring 3

DIS

0

DIS

1

DIS

2

DIS

3

DIS

4

DV

T40

QN

O40

QN

O30

DV

T30

5.19mm

Position [m]

a

Deflection [mrad]

-40

-30

-20

-10

0

10

20

51000 52000 53000 54000 55000 56000 57000 58000Ape

rtru

re [m

m]

Beam offset7.

27

-3.6

5

-3.4

9

-3.4

2

-3.6

2

-3.8

8

0 mrad → ring 3

DIS

0

DIS

1

DIS

2

DIS

3

DIS

4

DV

T40

QN

O40

QN

O30

DV

T30

5.19mm

Position [m]

a LINAC4 beam enters the BI.DIS

with a ~5.2 mm vertical offset.

The BI.DIS system, in combination with BI.DVT40, kicks slices of the beam into the different vertical septa BI.SMV.

a ~3.5 mrad deflection producing a vertical beam separation of 35 mm at the the BI.SMV.

In case of BI.DIS failure, the full beam is deflected by BI.DVT40 into an absorber block (head-dump).

29-01-2008 W. Weterings - LINAC4 Advisory Committee 6

Booster Injection Principle LINAC4 Pulse Structure

Proton Distributor BI.DIS

4 individual LINAC4 pulses, typically 65~100µs long with 1µs gap for BI.DIS rise-time. Fixed BI.DIS pulse lengths, but different for each magnet. Timing to be adjusted according to required number of injection turns from pulse to pulse.

Example: Operation65~100 injectedturns/ ring

DIS 0

DIS 3

DIS 2

DIS 1

DIS 4

65 to 100µs

1µsRing 4 Ring 3 Ring 2 Ring 1

HeadDump Tail

Dump

DIS 3

DIS 2

DIS 1

DIS 4

1µs 3 ~ 5µs

DIS 0Example: Pilot Beams

3~5 injectedturns/ ring

29-01-2008 W. Weterings - LINAC4 Advisory Committee 7

Booster Injection Principle Beam Separation

Magnetic Septa BI.SMV

The rising edge of the LINAC4 pulse is deflected to a absorber block (head dump). BI.SMV septa deflect the beam vertically into apertures of 3 separate BI.BVT vertical dipole

magnets to achieve the required PSB beam level separation of 360 mm between each ring. Beam designated for ring 3 will see no magnetic field and passes between SMV2 and SMV3. The falling edge of the LINAC4 pulse is deflected to a second absorber block (tail dump).

-800

-550

-300

-50

200

450

62000 63000 64000 65000 66000 67000 68000Position [m]

0 mrad

Tail Dump

Ring 4, 360mm

Ring 3, 0mm

Ring 2, -360mm

Ring 1, -720mm

SMV 1 -165.8 mrad

SMV 2131.3 mrad

BV

T

Head Dumpb SMV 3-131.1 mrad

-800

-550

-300

-50

200

450

62000 63000 64000 65000 66000 67000 68000Position [m]

0 mrad

Tail Dump

Ring 4, 360mm

Ring 3, 0mm

Ring 2, -360mm

Ring 1, -720mm

SMV 1 -165.8 mrad

SMV 2131.3 mrad

BV

T

Head Dumpb SMV 3-131.1 mrad

29-01-2008 W. Weterings - LINAC4 Advisory Committee 8

H- Injection System Principle

Booster Injection Region

Two independent closed orbit bump systems:

Injection Chicane, 4 pulsed dipole magnets (BS), located in the injection region, giving 60 mm beam offset during the injection process.

Painting Bump, 4 horizontal kickers (KSW), located outside the injection region, giving 27 mm closed orbit bump with falling amplitude over the injection process for transverse phase space painting.

BS1 must act as septum. BS4 should accommodate internal

Dump. Stripping efficiency of ~98% expected.

29-01-2008 W. Weterings - LINAC4 Advisory Committee 9

H- Injection System Foil Heating

Booster Injection Region

Temperature [K] of a 2 μm thick,400 μg.cm-2 graphite foil at the end of

the injection of 7 CNGS pulses.Peak foil temperature over 7 CNGS cycles.

29-01-2008 W. Weterings - LINAC4 Advisory Committee 10

Layout and Available Space

Side View

Top View

29-01-2008 W. Weterings - LINAC4 Advisory Committee 11

Layout and Available Space

29-01-2008 W. Weterings - LINAC4 Advisory Committee 12

Required Modifications

Remove obsolete BI.DIS Pb

New BI.SMV,4 mm thick septum and

70 mm horizontal aperture for

~180 mrad @ 160 MeV.New pulse generator.

~0.36 Tm required from BI.BVT for ~187

mrad @ 160 MeV

Rebuild the 2.654 m injection region of each of the 4 PSB rings:• 4 new BS magnets,• Foil holder and handler,• Dump for unstripped H0/H-,• Beam Instrumentation.

Modify BI.DIS for4.3 mrad @ 160 MeV

Performance increase of 1.9 in ∫B•dl of

BI.DVT30, BI.QNO30, BI.QNO40, BI.DVT40.

Relocate modified KSW1L1 magnet to PSB period 16, build new pulse

generator.

29-01-2008 W. Weterings - LINAC4 Advisory Committee 13

Required Modifications

Remove obsolete BI.DIS Pb

New BI.SMV,4 mm thick septum and

70 mm horizontal aperture for

~180 mrad @ 160 MeV.New pulse generator.

~0.36 Tm required from BI.BVT for ~187

mrad @ 160 MeV

Rebuild the 2.654 m injection region of each of the 4 PSB rings:• 4 new BS magnets,• Foil holder and handler,• Dump for unstripped H0/H-,• Beam Instrumentation.

Modify BI.DIS for4.3 mrad @ 160 MeV

Performance increase of 1.9 in ∫B•dl of

BI.DVT30, BI.QNO30, BI.QNO40, BI.DVT40.

Relocate modified KSW1L1 magnet to PSB period 16, build new pulse

generator.

29-01-2008 W. Weterings - LINAC4 Advisory Committee 14

Main Design Parameters

BI.DIS BI.SMV BS1,4 BS2,3

Deflection angle mrad 4.3 170 92 100

Integrated field mTm 8.2 324 175 190

Gap field mT 23.1 337 700 760

Beam acceptance mm 98 32 62 62

Gap width mm 50 70 130 200

Magnetic length Mm 354 960 250 250

Peak current kA 0.95 18.3 2.56 2.78

Magnet inductance μH 0.9 1.3 75 116

Magnet resistance mΩ 0.03 0.1

Number of turns 1 1 10 10

Repetition rate Hz 1.11 1.11 1.11 1.11

Rise / Fall time μs 1 40 40

Flat Top duration μs 420 100 100 100

29-01-2008 W. Weterings - LINAC4 Advisory Committee 15

BI.DIS - Design of new vacuum vessel well advanced.- Existing magnet tested for 160 MeV operation.- Specification for ferrite cores in preparation.- Coil design under study.- Challenge: Operation at 30 kV.

BI.SMV - Magnet parameters have been defined.- Design & prototyping planned to start mid 2008.- Challenge: Build curved, high induction, septum magnet to operate under vacuum.

KSW - Studies of moving 1L1 to period 16 ongoing.- If moved, build outside vacuum magnets.- Challenge: Beam optics compatibility.

Present Status

29-01-2008 W. Weterings - LINAC4 Advisory Committee 16

BS - Basic prototype has been tested to validate OPERA™ simulations.- 3D finite element transient field analysis ongoing.- Aperture and parameter optimization studies.- Challenge: Build cost-effective fast pulsed bumper system.

Foil Unit - Nuclear foil physics effects are being studied.- Challenge: Foil changing unit in limited space.

Ho/H- Dump & Head/Tail Dumps

- Thermo-mechanical studies being prepared.

- Challenge: Robust dumps in limited space.

Overall Challenge:

Injection system for 4 Superimposed PSB rings

Present Status

29-01-2008 W. Weterings - LINAC4 Advisory Committee 17

In order to distribute and inject the 160 MeV beam from LINAC4 into the four rings of the PSB, new distributor magnets and magnetic septa with a performance increase of 1.9 in ∫B·dl need to be built.

The pulse structure from LINAC4 will consist of 4 individual pulses, typically 65-100 μs long. The distributor pulse length will be fixed, but different for each magnet.

A completely new H- charge-exchange injection needs to be built comprising four injection dipole magnets, a stripping foil unit, an internal beam dump, and suitable instrumentation.

Conclusions