1. LAL meeting on e+ studies, 25-26 Oct. 2010
Prospect for KEKB linac operation -Present status and near future October Tsuyoshi Suwada Accelerator Laboratory, KEK
Tsuyoshi Suwada/KEKB Linac
LAL meeting on e+ studies, Oct. 2010

2. LAL meeting on e+ studies, 25-26 Oct. 2010
Introduction
The KEKB operation has been finished in the end of June 2010.
It was decided to approve the Super KEKB project in KEK in the end of June based on “the Funding Program for Next Generation World-Leading Researchers” established within the Japan Society for the Promotion of Science (JSPS).
One third　in total budget required for whole the construction was approved.
Discussions for the upgrade and R&D plans towards the Super KEKB have been started just now.
It is expected that the channeling experiments will be considerably disturbed during the construction of the Super KEKB.
Tsuyoshi Suwada/KEKB Linac
LAL meeting on e+ studies, Oct. 2010

3. experimental site KEKB LINAC
Tsuyoshi Suwada/KEKB Linac
LAL meeting on e+ studies, Oct. 2010 3

4. Super KEKB Accelerator Complex
Tsuyoshi Suwada/KEKB Linac
LAL meeting on e+ studies, Oct. 2010

5. Mission of Injector Linac for four rings towards Super KEKB project
Ring Energy Charge
[GeV] [nC]
PF (w top-up ope.) e
PF-AR (w/o top-up ope.) e
(w top-up ope.) ? e+? 4?
SKEKB (KEKB) LER e+ 4(←3.5) 4(←1)
SKEKB (KEKB) HER e- 7(←8.0) 5(←1)
Tsuyoshi Suwada/KEKB Linac
LAL meeting on e+ studies, Oct. 2010

6. Linac Parameter change key upgrade parameters are in red letters
Based on Kamitani, SuperKEKB Review 2010
Linac Parameter change key upgrade parameters are in red letters
KEKB Achieved
(e+/e-)
SuperKEKB Required (e+/e-)
beam energy
3.5 GeV / 8.0 GeV
4.0 GeV / 7.0 GeV
stored current
1.6A / 1.2A
3.6A / 2.62A
beam lifetime
150 min / 200 min
10 min / 10 min
bunch charge
10 -> 1.0 nC / 1.0 nC
10 -> 4.0 nC / 5.0 nC
# of bunches
2 / 2
beam emittance (ge)[1s]
2100 mm / 300 mm
10 mm / 20 mm
energy spread sE/E
0.125 % / 0.05 %
0.07 % / 0.08 %
bunch length sz
2.6 mm / 1.3 mm
0.5* mm / 1.3 mm e+
primary e– e+ e–
primary e– e–
Tsuyoshi Suwada/KEKB Linac
LAL meeting on e+ studies, Oct. 2010
*(assuming bunch compression after DR)

7. LAL meeting on e+ studies, 25-26 Oct. 2010
Injector Upgrade idea
(e-)
High intensity
Low emittance
Photo-cathode RF gun
(e+)
High intensity
Low emittance
AMD matching device (or Superconducting coil) + L-band Large-aperture capture section
Damping Ring
( e–& e+ )
Misalignment, RF kick, CSR
Alignment, etc.
(PF, PF-AR)
Pulse-by-pulse switching
Timing control
Tsuyoshi Suwada/KEKB Linac
LAL meeting on e+ studies, Oct. 2010

8. LAL meeting on e+ studies, 25-26 Oct. 2010
Present KEKB Injector
Based on Kamitani, SuperKEKB Review 2010 e– B A
Pulse-by-pulse beam switching for HER, LER & PF
Target bypass bump orbit (5 mm height)
Compatible optical setting for different beam energies
Switching of RF phases, ACC/DEC/STDBY timings & gun parameters
Independent orbit control with pulse steerings
for PF
2.5 GeV
0.1nC x 1
A1 gun
1.7 GeV
@J-arc
for HER
8.0 GeV
1nC x 2 C 1
target bypass
bump orbit 2 3 4 5
3T gun
moved from CT
C-band
module
for AR
3.0 GeV
0.1nC x 1 e+
10nC electron drive beam hit target at 4GeV
10% yield from electron to positron for 1nC positron
Positron to be accelerated to 3.5GeV
A1 gun B A
for LER
3.5 GeV
1nC x 2
4.0 GeV
10nC x 2 C 1 2 3 4 5
e+ target &
S-band capture section
ECS (Energy-spread
Compression System)
Tsuyoshi Suwada/KEKB Linac
LAL meeting on e+ studies, Oct. 2010

9. LAL meeting on e+ studies, 25-26 Oct. 2010
SuperKEKB Injector
Based on Kamitani, SuperKEKB Review 2010 e– B A
low emittance RF gun
for PF
2.5 GeV
0.1nC x 1
RF gun
emittance growth ?
in e– / e+ beams
1.7 GeV
@J-arc
for HER
7.0 GeV
5nC x 2 C 1 2 3 4 5
target bypass
bump orbit
e- bypass line for
DC separation bend
for AR
e– or e+ ? e+
Present A1 gun
for 10nC e– beam
Damping ring
A1 gun
1.1 B A
Nominally S-band acceleration
160MeV / RF unit (nominal)
+ 8m C-band at 4-4
Target moved to 1-4 for e+ energy margin
new matching dev. & L-band capt. section
for e+ intensity upgrade
for LER
4.0 GeV
4nC x 2 C 1 2
BCS
ECS 3 4 5
3.5 GeV
10nC x 2
e+ target, matching dev. &
L-band capture section
C-band
module x 2
ECS (Energy-spread
Compression System)
Tsuyoshi Suwada/KEKB Linac
LAL meeting on e+ studies, Oct. 2010

10. Injector upgrade gross plan (not yet fixed)
JFY2010
JFY2011
JFY2012
JFY2013
JFY2014
KEKB
oper.
HER, LER upgrade
SuperKEKB commissioning
DR component fabrication
DR tunnel construction
Conflicting items
Installation
DR building construction
DR commissioning
1 Apr. 2011
31 Jan. 2012
DR-Inj
Connection
No beam delivering
8-GeV beam delivering under limited condition
e+ matching device R&D
e+ matching device & capture section construction
e+ beam commissioning
L-band and LAS development
L-band & LAS module construction
RF-gun & laser system design
e- beam commissioning
Full-spec RF gun and laser
Establish at A1
A1 gallery
extension
Laser alignment study
Actual alignment system
Keep PF, AR injection with 3T gun and/or A1 gun, then add SuperKEKB from JFY2014
Tsuyoshi Suwada/KEKB Linac
LAL meeting on e+ studies, Oct. 2010

11. LAL meeting on e+ studies, 25-26 Oct. 2010
Summary
Discussions on the construction & R/D plans for the upgrade of the KEKB injector towards the Super KEKB has been started just now (October 2010).
The tentative plan has been now developed and maybe it will be fixed by the end of 2010.
A lot of R&D works will start soon.
It is expected at least that the channeling experiments are not available during the term from 1 Apr to 31 Jan. 2012, and even after this term it will be considerably limited for the use of 8-GeV electron beams up to the start of the commissioning which will be scheduled at the middle of FY2013.
The next scheduled chance to perform the experiment is the beginning of Jan Another chance is not clear at present.
Tsuyoshi Suwada/KEKB Linac
LAL meeting on e+ studies, Oct. 2010

12. KEKB Accelerator Complex (+PF, AR)
Tsuyoshi Suwada/KEKB Linac
LAL meeting on e+ studies, Oct. 2010