Injector Upgrade:toward 4-rings simultaneous injection

M. Satoh, for the Injector Upgrade WG members

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Feb. 21-23, 2005

= Contents =1. Introduction
2. Simultaneous Injection Scheme(based on the Multi-Energy Linac Scheme)
3. Upgrade Plan
1. Phase-I (Construction of A New PF-BT line)
2. Phase-II (Simultaneous injection: KEKB e-, PF e-)
3. Phase-III (Simultaneous injection: KEKB e-/e+, PF e-, PF-AR e-)

4. Budget and (Phase-I) Construction Schedule
5. Summary
M. SATOH/ KEKB Linac Control

KEKB Review Committee, Feb. 21-23, 2005

- 1. Introduction -= KEKB Injector Linac =• 600-m long linac with 180-deg. ARC section.
• Used for KEKB e-/ e+, PF, PF-AR injector.

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Feb. 21-23, 2005

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

M. SATOH/ KEKB Linac Control

AR

KEKB Review Committee, Feb. 21-23, 2005

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

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Feb. 21-23, 2005

- 1. Introduction -= Issue of Current Beam Injection Mode =• One linac is used as an injector for 4-rings (time sharing).
• Changing the beam mode (KEKB => PF, PF-AR) takes time (2 or 3 min.)because ECS needs the magnet standardization.
• Super-KEKB needs the simultaneous beam injection (e- and e+).
• In the present operation, PF (and PF-AR) machine study interrupt theKEKB continuous injection.
• PF-ring needs the Top-up injection mode in the future.
• PF-AR also needs Top-up (6.5-GeV e-) injection (if possible).
= PF-AR BT needs to replace many magnets and power supplies (Large cost)• To solve the above problems, simultaneous injection
scheme is strongly required. (beam mode switching inpulse-by-pulse).
M. SATOH/ KEKB Linac Control

KEKB Review Committee, Feb. 21-23, 2005

- 1. Introduction ● Current beam mode switch (KEKB e- Ù e+)
KEKB e- KEKB e- KEKB e- KEKB e-20-ms (50-Hz) RF pulse cycle

KEKB e+ KEKB e+ KEKB e+ KEKB e+mode switch (30 sec)

● Current beam mode switch (KEB e-/e+ Ù PF/ PF-AR)
KEKB e- KEKB e- KEKB e- KEKB e-20-ms (50-Hz) RF pulse cycle

PF e-PF e-PF e-

PF e-mode switch (2-3 min.)● Simultaneous injection (Pulse-by-pulse beam mode switch)
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, Feb. 21-23, 2005

- 2. Simultaneous Injection 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 klystron or sub-booster
phase quickly.
– Beam is accelerated up to ~5.3 GeV then decelerated to 2.5 GeV using
deceleration phase (PF e-).
– KEKB/PF/AR should use common electron Gun A1.

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Feb. 21-23, 2005

- 2. Simultaneous Injection 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.
••"2.5 GeV" e- optics

Orbit correction satisfies bothenergies can be made.
Normalized emittance of 8 GeV issimilar to "2.5 GeV" e- optics.

8 GeV e- optics

Deceleration phase

Measurement of energy and emittance• Energy = 2.7 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, Feb. 21-23, 2005

- 2. Simultaneous Injection Scheme-= Preliminary Machine Study for Multi-Energy Linac (2) =Y. Ohnishi••

Multi-Energy Linac is feasible for practical operation.
Need more Machine Study.

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Feb. 21-23, 2005

- 3. Upgrade Plan-= Upgrade Overview =• Upgrade work consists of three phases:• Phase-I: Construction of New PF-BT line in this summer FY05
(bypass ECS)
Save time for switching beam mode (KEKB Ù PF)• Phase-II: Simultaneous Injection (KEKB e-, PF e-)• Phase-III: Simultaneous Injection (KEKB e-/ e+, PF e-, PF-AR e-)• To save costs, spares should be used (magnet, monitor, …) as many aspossible.
• Phase-III schedule depends on budget allocation.
• It should be carried out as soon as possible.

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Feb. 21-23, 2005

- 3.1 Phase-I (Upgrade Plan)= Phase-I New PF-BT Layout =• 5-8 accelerating unit will be removed. In order to compensate theenergy margin, C-7 section uses SLED system.
• DC Bend will be installed in this summer. It will be replaced bypulse bend in FY05 winter /or FY06 summer.
Remove 58 accelerating unit

BMM. SATOH/ KEKB Linac Control

KEKB Review Committee, Feb. 21-23, 2005

- 3.1 Phase-I (Upgrade Plan)

5-8 unit wave guide is a obstacle for new PF-BT.

New PF-BTBend
M. SATOH/ KEKB Linac Control

KEKB Review Committee, Feb. 21-23, 2005

- 3.1 Phase-I (Upgrade Plan)

Photograph of 3-SY

New PF-BT

3M. SATOH/ KEKB Linac Control

KEKB Review Committee, Feb. 21-23, 2005- 3.1 Phase-I (Upgrade Plan)= Phase-I New PF-BT Optics =dP/P=0.125% (1σ),ε=1.6e-7m

1.91times(η=-2.17m:2.56mm, β=13.6m:1.34mm)

Install Energy spread monitor

M. SATOH/ KEKB Linac Control

N. IidaKEKB Review Committee, Feb. 21-23, 2005

- 3.1 Phase-I (Upgrade Plan)= Energy-Spread Monitor (ESM) =•Three ESMs have bees installed, and it works wellin daily operation J-ARC, KEKB BT (e-, e+)・Same type of ESM will be installed in NEW PF-BT.
・Energy-spread Feedback will be carried out.

Trend plot application

M. SATOH/ KEKB Linac Control

Alarm panel

KEKB Review Committee,
Feb. 21-23,
2005
Photographof ESM

- 3.1 Phase-I (Upgrade Plan)= Compensation for 5-8 unit energy gain (160-MeV) =• Use C-7 unit SLED.
• 4-4 unit (C-band unit) will complete.
(1 acc. structure => 4 acc. structures with SKIP)
C-7 unit= Current == Phase-I =KlystronC-7 unit

CT unit (from 5-8)
Klystron

SLED (detuned)

SLED

BuncherPre-buncher

BuncherPre-buncher

beam

CT Gun(for PF, PF-AR)

M. SATOH/ KEKB Linac Control

beam

CT Gun(for PF, PF-AR)

KEKB Review Committee, Feb. 21-23, 2005

- 3.2 Phase-II (Upgrade Plan)- KEKB and PF uses common electron Gun (A1) • KEKB and PF will be operated by common Gun (A1).
•Use common magnetic field (Quadrupole, Steering).
•Change only the klystron phase.

A1 GunCT GunM. SATOH/ KEKB Linac Control

KEKB Review Committee, Feb. 21-23, 2005

- 3.3 Phase-III(Upgrade Plan)= KEKB e-/ e+, PF, PF-AR =・ Use common magnetic field (Multi-Energy Linac Scheme)
・ Use e+ target with a hole.
・ For fast switch (e-/ e+ mode) :Change the e- beam orbit (Use fast steering magnet.)
・ In this summer, e+ target replaced by crystalline tungsten with a hole)
Current e+ target

e+ target for phase-III(amorphous tungsten)(crystalline tungsten with hole)primary e- for e+e- beam (e- mode)
Hole for e- bypass
M. SATOH/ KEKB Linac Control

KEKB Review Committee, Feb. 21-23, 2005

- 4. Budget and Construction Schedule= Construction Schedule for Phase-I (this summer) =・ Schedule is very tight (only 8 weeks).
・ Other works during summer maintenance:
・ C-Band accelerating structures(x3)・ Replacement of e+ target (amorphous tungsten => crystalline tungsten)
July

August1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Power cut
SurveyMarking-off

Linac start

Alignment

Carry out Q-mag.
Measurement of magnetic field
Magnet installation
Vacuum pipe assemb Vaccume works
5-8 Cooling water pipe rearrange
cabling

Cable edge processing

5-8 unit removal
5-8 gallery rearrange
shield block move

Bring in PS

Interlock Test

Magnet running test

Shield block for collimator
Safety system test

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Feb. 21-23, 2005

- 4. Budget and Construction Schedule= Budget =Phase-I
Phase-II
Phase-III[ US$ million ]
1.18
0.11?

• Phase-II:
Grid purser and timing system (use A1 Gun for PF e- beam).
• Phase-III:
Beam monitor DAQ system for pulse-by-pulse measurement.
We will start R&D soon.
(fast waveform digitizer based on c-PCI)
Need fast phase shifter.

M. SATOH/ KEKB Linac Control

KEKB Review Committee, Feb. 21-23, 2005

5. Summary
KEKB injector linac upgrade project will start in thissummer (FY05, Phase-I) toward the simultaneousinjection (KEKB e-/ e+, PF e-, PF-AR e-; Phase-III).
 Use “Multi-Energy Linac scheme”:
Common magnetic field and fast change of klystron phase.
 Machine study result shows feasibility. (Need more Study)Remaining issue (PF-AR Top-up injection):Difficult to realize PF-AR Top-up (6.5-GeV) w/o large budget.
(Current PF-AR BT can transport beam 3.1-GeV max. )Make a decision to PF-AR injection scenario .
(give up PF-AR Top-up?)
M. SATOH/ KEKB Linac Control

KEKB Review Committee, Feb. 21-23, 2005