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