Injector Upgrade:for Fast Beam-Mode Switch
M. Satohfor the Injector Upgrade (IUC) WG members

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

= Contents =1. Introduction (Background of Upgrade)
2. Fast Beam-Mode Switch Scheme(based on the Multi-Energy Linac Scheme)
3. Upgrade Plan
1. Phase-I (Construction of A New PF-BT line) = Completed in last summer =2. Phase-II (Fast Beam-Mode Switch: KEKB e-, PF e-)
3. Phase-III (Fast Beam-Mode Switch: KEKB e-/e+, PF e-, PF-AR e-)

4. Summary

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

- 1. Introduction -Beam operation statistics of Linac• Injector linac for 4-rings (KEKB e-/ e+, PF, PF-AR)• Continuous Injection Mode (CIM) has started in 2004.
CIM Mode
KEKB e- mode
1 min.

Linac Bema-Mode Change
30 sec.

KEKB e+ mode
4 min.

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

- 1. Introduction -Beam-Mode Switching Operation
Change magnetic field Change timing
 Insert/ Remove e+ target (e-/ e+) Klystron mode (Acceleration/ Standby mode) Klystron (Sub-Booster Klystron) phase Etc.
M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

- 1. Introduction -= Typical KEKB Operation =• KEKB-ring is operated under Continuous Injection Mode.
• PF and PF-AR need twice injection a day.
PF AR

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

- 1. Introduction -•Machine Study (PF, PF-AR) interrupts KEKB continuous injection.

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

- 1. Introduction -= Issue of Beam Operation =• Only one linac is used as an injector for 4-rings (time sharing).
• Changing the beam mode (KEKB <=> PF, PF-AR) takes time
(Need ECS standardization)• PF and PF-AR machine study need continuous injection.
• Super-KEKB needs Fast Beam-Mode Switch Injection (e- and e+).
• PF-ring needs the Top-up injection mode in the future.

• Fast Beam-Mode Switch scheme is strongly required.
(quasi-simultaneous injection)
KEKB e- KEKB e+ KEKB e- KEKB e+ PF e- PF-AR e-PF e-KEKB e+20-ms (50-Hz) RF pulse cycle
M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

- 2. Fast Beam-Mode Switch Scheme-= Multi-Energy Linac Scheme =• Fast change of the magnetic field is difficult by using current system.
• Use the common magnetic field (Quadrupole and Steeringmagnets)• Energy adjustment be done by changing sub-booster klystron phasequickly.
– Beam is accelerated up to ~5.3 GeV then decelerated to 2.5 GeV using
deceleration phase (PF e-).
– All beam modes (KEKB e-, e+ /PF /AR) use common electron gun (A1 gun).

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

- 2. Fast Beam-Mode Switch Scheme= Preliminary Machine Study for Multi-Energy Linac (1) =•Common magnet setting has been tested for 2.5-GeV and 8-GeV e- beams.

•Optics difference comes from acceleration phase.

••

Orbit correction satisfies both energies can be made.
Normalized emittance of 8-GeV is similar to 2.5-GeV e- optics.

2.5-GeV e- optics (for PF)

8-GeV e- optics (for KEKB e-)

Deceleration phase

Measurement of energy and emittance• Energy = 2.5 GeV (SC61H)• γεx = 3.6x10-4 m• γεy = 6x10-5 m

M. SATOH/ KEKB Linac Control• Energy = 8 GeV (SC61H)• γεx = 2.5x10-4 m• γεy = 4x10-5 m

Y. Ohnishi

KEKB Review Committee, Mar. 21-23, 2006

- 2. Fast Beam-Mode Switch Scheme= Preliminary Machine Study for Multi-Energy Linac (2) =Y. Ohnishi••

Multi-Energy Linac scheme is feasible for practical operation.
Machine study is going on.

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

Preliminary Study Result:
PF Injection on Multi-Energy Linac Scheme• Injection rate is almost same with daily operation.
• KEKB injection should be tested on multi-energy scheme.

Injection rate: 1.5 mA/sec @ 25 Hz

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

- 3. Upgrade Plan-

Upgrade work will be done by three phases:• Phase-I (done): Construction of New PF-BT line (bypass ECS)
Save time for switching beam mode between KEKB and PF.

= Use Multi-Energy Linac Scheme =• Phase-II: Fast Beam-Mode Switch (KEKB e-, PF e-)• Phase-III: Fast Beam-Mode Switch (KEKB e-/ e+, PF e-, PF-AR e-)

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

- 3.1 Phase-I (Upgrade Plan)

ECS handling for each mode

KEKB Ù PF/ PF-AR needs ECS standardization.
KEKB CIM mode
ECS ONKEKB e+ (3.5-GeV e+)

PF-AR mode
ECS Change

KEKB (8-GeV e-)

Beam dump
PF-AR (3-GeV e-)
PF modeECS OFFPF (2.5-GeV e-)

Beam dump

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

- 3.1 Phase-I (Upgrade Plan)= Phase-I New PF-BT Layout =• New PF-BT has been constructed in last summer.
Remove 58 accelerating unit

BMOld PF-BT

New PF-BT

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

New PF-BT to bypass the ECS magnets
ECS is always ON. (KEKB e-/ e+ and PF modes)
 It shorten time for beam mode change. (KEKBÙPF)PF (2.5-GeV e-)
PF modeECS ON

New PF-BT
Old PF-BT

Bend (BM_58)

M. SATOH/ KEKB Linac Control

Beam dump

KEKB Review Committee, Mar. 21-23, 2006

- 3.1 Phase-I (Upgrade Plan)

Photograph of 3-SY (Before Phase-I)New PF-BT

3M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

= After Phase-I =PF

Switch DC Bend

KEKB/ ARDC bend will be replacedby pulsed bend in this summer
M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

New PF-BT (since FY05 summer)

New PF-BT

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

After Phase-I• Bema-Mode Switch “KEKB Ù PF” has been much improved.

• 5 min. 30 sec. => 2 min. 30 sec.
(KEKB mode => PF mode => PF injection => KEKB mode)

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

- 3.2 Phase-II (Upgrade Plan)- Fast Beam-Mode Switch: KEKB e- and PF mode
•Multi-Energy Linac Scheme•KEKB and PF use a common electron gun (A1).

A1 GunCT GunM. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

- 3.3 Phase-III(Upgrade Plan)= Fast Beam-Mode Switch: KEKB e-/ e+, PF, PF-AR =For fast switch (e-/ e+ mode) :• Use e+ target with a hole.
• Control e- beam orbit.

primary e- for e+e- beam (e- mode)
Hole for e- bypass

Amorphous tungsten
target:φ5 mmview from upstream

4.5 mmHole:φ3 mm
M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

Preliminary Machine Study Result: e+ target with a hole
Orange dots: w/o target (normal operation)
 Blue dots: target (with a hole) Traversing rate is about 90% in comparison withnormal operation.
H
[mm]
V
[mm]
Charge[nC]
T. Kamitani and T. Sugimura
M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

Remaining Hardware Issue:
BPM DAQ System should be
upgraded to measure beam
position up to 50 Hz.
 New System is under test.
BPM DAQ system(VME + Oscilloscope with GPIB)

Timing system should control thecomplicated operation mode inPhase-III.
 Event generator (EG) andReceiver (ER) based on VME-64
will be tested soon.
New system under test
(Fast Win. Based-Oscilloscope/ EPICS)
M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

Scenario for PF-AR Injection

It is difficult to realize PF-AR Top-up (6.5-GeV) w/olarge budget. (Current PF-AR BT can transport beam
3.1-GeV max. )One solution: Use KEKB e+ (3.5-GeV) beam for PFAR injection. It also needs large budget.
Need to replace some PS of bend (@AR-BT).
 Need to replace Septum and Kicker PS
 Need pulsed bend and PS
 Cost estimation and design work should be done soon.
M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006

4. Summary

KEKB injector linac upgrade project has started inlast summer toward Fast Beam-Mode Switch.
(KEKB e-/ e+, PF e-, PF-AR e-).

Phase-I completed (New PF-BT line):

It can shorten time for beam mode switch (KEKBÙPF)Phase-II and III
Use “Multi-Energy Linac scheme”:
 Use common magnetic field and fast change of rf phase.
 Machine study result shows feasibility.
 Machine study is going on.
Need detailed design work of beam operation.
 After complete upgrade, linac beam operation will
become more effective.
M. SATOH/ KEKB Linac Control

KEKB Review Committee, Mar. 21-23, 2006