1. Progress of Injector Linac
Kazuro Furukawa
for Injector Linac

2. Mission of electron/positron Injector in SuperKEKB
Linac Upgrade Overview
Mission of electron/positron Injector in SuperKEKB
40-times higher Luminosity
Twice larger storage beam  Higher beam current at Linac
20-times higher collision rate with nano-beam scheme 　
 Low-emittance even at first turn  Low-emittance beam from Linac
 Shorter storage lifetime  Higher Linac beam current
Linac challenges
Low emittance e-
with high-charge RF-gun
Low emittance e+
with damping ring
Higher e+ beam current
with new capture section
Emittance preservation
with precise beam control
4+1 ring simultaneous injection
Higher Injection Beam Current
To Meet the larger stored beam current and shorter beam lifetime in the ring
4~8-times larger bunch current for electron and positron
Reconstruction of positron generator, etc
Lower-emittance Injection Beam
To meet nano-beam scheme in the ring
Positron with a damping ring
Electron with a photo-cathode RF gun
Emittance preservation by alignment and beam instrumentation
Quasi-simultaneous injections into 4 storage rings
SuperKEKB e–/e+ rings, and light sources of PF and PF-AR
Improvements to beam instrumentation, low-level RF, controls, timing, etc

3. Required beam parameters
Stage
KEKB
Phase-I
SuperKEKB
Item e+ e-
Energy
3.5 GeV
8.0 GeV
4.0 GeV
7.0 GeV
Bunch charge
Primary e-10nC
→ 1 nC
1 nC
Primary e- 4nC
→ 0.2 nC
→ 4 nC
5 nC
Norm.Emittance (ge)
(mrad)
2100
100
2400
150
100/20 (Hor./Ver.)
50/20 (Hor./Ver.)
Energy spread
0.125%
±0.5%
0.1%
Num. of Bunch / Pulse 2
Repetition rate
50 Hz
Simultaneous top-up injection
3 rings
(KEKB e-/e+, PF)
No top-up
4 rings
(SuperKEKB e-/e+, PF, PF-AR)

4. SuperKEKB upgrade construction Startup, conditioning, etc.
SuperKEKB master schedule
・・・
JFY2010
JFY2011
JFY2012
JFY2013
JFY2014
JFY2015
JFY2016
JFY2017
・・・
Now (Nov, 2015)
KEKB operation
Dismantle KEKB
Phase 2 commissioning：
Squeezing beta at IP
Beam collision tuning
Start physics data taking
SuperKEKB upgrade construction
Phase 3：
Physics run with full Belle II with VXD
Startup, conditioning, etc.
SuperKEKB operation
Phase 1
Phase 2、3
Phase 1 commissioning：
Basic machine tuning
Low emittance beam tuning
Vacuum scrabbing DR
About 10 years
Belle II install,
QCS install
DR commissioning starts prior to Phase 2
Akai, Jun.2015.

5. Linac Schedule Overview
RF-Gun e- beam
commissioning
at A,B-sector
e- commiss.
at A,B,J,C,1
e+ commiss.
at 1,2 sector (FC, DCS, Qe- 50%)
e- commiss.
at 1,2,3,4,5 sector
Phase1: high emittance beam for vacuum scrub
Phase2,3: low emittance beam for collision
Time →
Location ↓
Step-by-step Licenses
Low Emittance Beams
4+1 Ring
Injections
DR Commiss.
1 nC
Phase1
2 nC
Phase2
4 nC
Phase3
Without Top-up
Direct PF-AR BT
non damped e+ commiss.
at 1,2, 3,4,5 sectors
e- commiss. at A→5 sectors
damped e+ commiss.
at 1→5 Qe+ = 1~4nC
e- commiss.
at A→5 Qe- = 1~5nC
Improved RF gun
: Electron
: Positron
: Low current electron

6. Subjects to Consider Too many subjects !
Phronesis needed (Greek: Practical wisdom, Ability to understand the Universal Truth)

7. Linac Upgrade Progress towards SuperKEKB (1)
Linac Upgrade Overview
Linac Upgrade Progress towards SuperKEKB (1)
High-charge low-emittance RF gun development
QTWSC cavity and Ir5Ce photo cathode developments
Positron generator commissioning
Good agreement with the simulation results
Precise alignment for emittance preservation
Recovering after earthquake
Reaching specification of 0.3mm
Utility upgrade during FY2014
for electricity (+1.5MW) and cooling water (+1400L/min)
Quasi traveling wave side couple cavity
Ir5Ce Cathode
Positron generator
Signal from primary electron
Signal from positron with opposite polarity

8. Linac Upgrade Progress towards SuperKEKB (2)
Linac Upgrade Overview
Linac Upgrade Progress towards SuperKEKB (2)
High power modulator upgrades
Low-level RF controls/monitor
Pulse-to-pulse modulation (PPM) between 4+1 rings
More spaces for increased number of devices
Beam instrumentation
Large/small aperture beam position monitors (BPM)
Precise/fast and synchronized BPM readout system
Wire scanners and beam loss monitors
Streak cameras
(Deflectors, etc)
Event timing control system
Combination of MRF & SINAP modules
Essential for PPM operation
Precise timing & synchronized controls
Bucket selection at DR and MR
SINAP event modules
Beam wire scanner

9. Recent Works Positron generator at #15 region Iron shield
Positron generator complex
Thermionic gun at #A1 region
Thermionic gun
for high-current beam
RF gun
for low-emittance beam

10. Preparation of Thermionic Gun
Refurbished and recommissioned
Raise by 75cm not to conflict with straight RF-gun
As well as angled RF-gun
~ Jun.2015.
Beside RF gun, thermionic gun may serve
electrons in phase-I
primary electron for positron generation in phase-II and later
Thermionic gun
RF gun

11. Positron generation for SuperKEKB
Positron Enhancement
Positron generation for SuperKEKB
bridge coils
side view
solenoid
primary
e- beam
10 nC
primary e-
DC QM
LAS Accel.
structure
spoiler
target e+
positron
production
Target
5 nC injection e-
beam
hole
Flux
Concentrator
pulsed ST
Flux
Concentrator
pulsed QM
Bridge
Coils
e+ beam
New positron capture section after target with Flux concentrator (FC) and large-aperture S-band structure (LAS)
Satellite bunch (beam loss) elimination with velocity bunching
Pinhole (2mm) for passing electrons beside target (3.5mm)
Recently, facing discharge difficulties at maximum field

12. Radiation protection licenses
Schedule
Radiation protection licenses
Step-by-step upgrade of beam limits
Final goal is 1250/625 nA before/after target
Same as KEKB
License applications
Fall nA at #28 dump, 1250 nA at #A2 dump
Spring New utility rooms, 50 nA at #61 straight dump
Jun nA at #15 target
Early 2016.(?) 800 nA at #15 target, 625 nA at #61
Sometime 2016.(?) 1250 nA at #15 target
Shield, shield, shield, shield …
Gun, 180deg-arc, Target, Electron stopper, Collimator, etc

13. Summary Steady progress towards first MR injection in FY2015
Finished earthquake disaster recovery in 2014
Will make step-by-step improvements up to Phase-III
Alignment: almost confident on the required precision (0.1-mm local, 0.3-mm global), need to maintain for longer term
Positron generator: another license test, need discharge analysis
Thermionic gun: re-commissioned, working
RF gun: following recommendations at review meetings
Need much more radiation shield
Will balance between final beam quality and progressive operation
Will select optimized route depending on available resources
With some Phronesis we may enjoy coming beam commissioning

14. Thank you Mt. Tsukuba SuperKEKB dual rings PF-AR PF
600m Injector Linac

16. Alignment
Alignment
High-precision alignment was not necessary in PF and KEKB injections, and it was much damaged by earthquake in 2011.
Instead of flexible-structure girder before earthquake, rigid-structure was adopted with jack-volts and fixed supports.
Reflector pedestals are developed and mounted onto quad magnets and accelerating cavities for laser-tracker measurement.
Iterative measurement and adjustment with 500-m straight laser and position sensors should enable 0.3-mm global alignment.
Laser tracker should enable 0.1-mm measurement within 10-m girder unit.
Displacement gauges, hydrostatic leveling, inclinometer are also employed.
Remote measurement system and girder mover system will be necessary for longer term, and are under development.

17. Hardware alignment on girders in sectors 3~5
Horizontal
Vertical
Horizontal
s=34mm
Vertical
s=47mm
Higo et al.

18. Floor vertical movement in a half year from summer to winter
Alignment
Floor vertical movement in a half year from summer to winter
Higo et al. C3 11 18 28 38 48

19. Pulse-to-pulse modulation
ARC
e– (2.5GeV, 0.2nC)
e− Gun
e+ Target
e+ (4GeV, 4nC)
PF Injection
SuperKEKB-LER Injection
e– (3.5GeV, 10nC)
e– (7GeV, 5nC)
SuperKEKB-HER Injection
e– (6.5GeV, 5nC)
PF-AR Injection
Damping ring
Event-based Control System
Every 20 ms
F.B
Four PPM virtual accelerators for SuperKEKB project based on Dual-tier controls with EPICS and event-system Independent parameter sets for each VA (20ms separate) >200 parameters for equipment controls many more for beam controls