1. RF-Gun for Phase-II
RF Gun 10, June, 2016

2. Schedule Last RF-Gun review Done On going
Reconfigure thermal gun for positron generation
Step by step RF-Gun RF ageing.
Done
SuperKEKB injection using stabilized existing undergroud laser (25Hz)
New laser system in 3-2 and A-1 ground laser room
Increase stability & pulse energy from fiber laser
Simplify the laser system (Nd/Yb Regenerative amplifier)
On going
Third RF-Gun (nomal laser injection / cavity modification / cathode change)
Simple Nd amplifier for Phase-I & II stable injection
Following the RF-Gun reviewer’s comments
(Postponed the pulse shaping until Phase-III )
10 ps gaussian is enough for Phase-I (1nC) & II (2nC), postponed the pulse shaping until Phase-III

3. RF-Gun for Phase-II RF-Gun (Natsui) Cathode (Sato)
Backup SC-QTW is already available (RF ageing was done)
New CDS-type RF-Gun is under fabrication
Second RF-Gun will be installed in this summer shutdown with 90-degree arc section.
Cathode (Sato)
Better QE uniformity : Ir7Ce2

4. Second RF gun on the 45 degree line
Normal laser injection
RF conditining at 6-1 is on going before installation.
Studies on
CDS-type RF-Gun cavity.
Normal laser injection.
Changeable cathode including thermal assist IrCe.
Angled
laser
injection

5. Choke mode cathode rod fix
Breakdown at cathode rod is one of the problem.
New gun will be choke structure.
Dummy cathode rod is used.
No cathode, all copper.

6. Simple cavity RF gun is developed for test
Cut Disk Structure
(CDS)

7. Laser for Phase-II Simplification Stabilization Higher power output
10.38 MHz oscillator (higher pulse energy / no pulse picker / lower ASE)
Nd:YAG Regenerative amplifier
Stabilization
Pointing feedback system
Commercial oscillator
Vacuum optical transmission line
Reduction of environmental noise ( casing etc,.)
Higher power output
Nd:YAG disk stack with 885 nm pump

8. Yb fiber and Nd/Yb solid laser system on the A-1 ground
Yb fiber part (already installed)
Repetition frequency
114.24MHz
Wavelength selection
1030nm & 1064nm
Repetition frequency
10MHz
1064nm oscillator
(ANDi type)
Grating stretcher
(Transmission)
SOA
pulse picker
Yb single mode
fiber amp
Menlo
1030nm oscillator
FBG
FBG
Yb-doped double clad
fiber amp
ASE rejection
grating pair
1030nm oscillator
(ANDi type)
1064nm
1030nm
1030nm oscillator
(10.38 MHz)
EO pulse picker
Yb:YAG Thin disk
regenerative amplifier
1064nm
Nd:YAG
regenerative amplifier
Cryogenic Yb:YAG Thin disk
main amplifier
Nd:YAG
main amplifier
Nd:YAG
for Phase-II
Output(1064nm)
Output(1030nm)
Yb:YAG
for Phase-III
96ns Delay => Combine => SHG => FHG

9. Nd:YAG regenerative amplifier

10. For Phase-III New 90-deg beamline Laser Cathode (Sato)
Detailed bunch shape monitor (RF-Deflector)
Bunch shaping by slit at 90-deg arc
Laser
Chirp pulse amplification with pulse shaping
Yb:YAG regenerative amplifier + Cryogenic Yb:YAG main amplifier
Cathode (Sato)
QE improvement using single crystal IrCe cathode
Thermal assist for higher QE & cathode cleaning