SuperKEKB Review /Electron gun and transport
Mitsuhiro Yoshida2015.02.24

SuperKEKB upgrade
for low emiCance electron beam
High charge low emiCance isrequired for SuperKEKB.

KEKB obtained(e+ / e-)SuperKEKB
required (e+ / e-)

Beam energy

3.5 GeV / 8.0 GeV

4.0 GeV / 7.0 GeV

Bunch chargee- e+ / e10  1.0 nC / 1.0 nC

e-  e+ / e10  4.0 nC / 5.0 nC

Beam emittance(γε)[1σ]2100 µm / 300 µm

6 µm / 20 µm

5 nC 10 mm‐mrad electron beam generated by RF gun.
+ 10mm‐mrad emiCance preservaLon is required.
Quasi –travelling side couple RF‐Gun
with Yb laser system

B
J‐ARC

C

Preliminary test using DAW RF‐Gun
with Nd laser system
due to earthquake

A
10ps

30ps

1

2

3

4

5

RF‐Gun for 5 nC
20

• Space charge is dominant.
• Stable operaLon is required.
– Lower electric ﬁeld : < 100MV/m• Focusing ﬁeld must be required.

emittance(SC)̲x@5nC&90MV/m

16

Emittance (mm mrad)– Longer pulse length : 20 ‐ 30 ps

emittance(RF)̲x@5nC&90MV/m

18

emittance(total)̲x@5nC&90MV/m

14
12
10
8

Total

6
4

Space charge
RF

2
0
0

10

20

30

40

Tlaser (ps)– Solenoid focus causes the emiCance growth.
– Electric ﬁeld focus preserve the emi3ance.
Epaxial coupled cavity : BNL
Annular coupled cavity : Disk and washer / Side couple50

S‐band RF‐Gun development strategy for SuperKEKB• Cavity : Strong electric ﬁeld focusing structure– Disk And Washer (DAW)=> 3‐2– Quasi Traveling Wave Side Couple => A‐1=> Reduce beam divergence and projected emiCance diluLon• Cathode : Long term stable cathode– Middle QE (QE=10‐4〜10‐3 @266nm) and long lifeLme– Solid material (no thin ﬁlm) => Metal composite cathode=> Started from LaB6 (short life Lme)=> Ir5Ce has very long life Gme and QE>10‐4 @266nm• Laser : Stable laser with temporal manipulaLon– LD pumped laser medium• Nd doped solid laser• Yb doped ﬁber and solid hybrid laser– Temporal manipulaLon => Yb doped=> Minimum energy spread=> 3‐2=> A‐1

Pill‐box cavity

Annular coupled cavity with nose

AcceleraLng ﬁeld

AcceleraLng ﬁeld
加速電場

ビーム
Beam

Beam

=> Strong focus

Field

Ez, Er/r

Ez, Er/r=> Weak focus

Field
Focussing ﬁeldzAcceleraLng ﬁeld

Focussingﬁeld
Given forcez

Focussingﬁeld

AcceleraLng ﬁeld

Ez, Er/r

Ez, Er/r

AcceleraLng ﬁeldzAcceleraLng ﬁeld

Given forcez

Focussingﬁeld

5

Closed gap makes focus ﬁeld
Side coupled cavity is one candidate (or DAW / ACS / CDS …)

Concentrated ﬁeld
has focusing eﬀect

This structure has long drig space

This structure has focusing ﬁeld.
Long drig space is problem.
6

Design of a quasi traveling wave side couple RF gun
Normal side couple structure

Quasi traveling wave sidecouple structure

Quasi traveling wave side couple has stronger focusing andaccelerated gradient than DAW.

Quasi traveling wave side couple RF gun
This RF gun has total of seven acceleration cavities. These are divided into
two standing wave structure of 3 and 4 side coupled cavities respecLvely.
Cathode cell
To avoid beam defocusing, emiCancegrowth and ﬁeld concentraLon, a lot ofparameters were searched for design.

cathodeMaximum E‐ﬁeld at
surface: 120 MV/m

Maximum E‐ﬁeld at surface: 100 MV/m

EmiCance: 5.5 mm‐mrad @ 5 nC
This RF gun can generate 10 nC beam

Beam tracking simulaLon result
5 nC

10 nC

EmiCance 5.5 mm‐mrad

Gun Exit
Size 0.4 mm

time=2.48098e-009

Energy [MeV]

11.7
11.6

Energy spread
0.6%

11.5

Bunch
shape

11.4
11.3

728
GPT

729

730

z

731

732

733

RF‐Gun comparison
Quasi traveling wave side couple RF gun(100 MV/m, 6mm‐mrad, 13.5 MeV)
DAW‐type RF gun(90 MV/m, 5 mm‐mrad, 3.2 MeV)
BNL‐type RF gun(120 MV/m, 11.0 mm‐mrad, 5.5 MeV)
BNL (3.8 mm)
DAW (1.7 mm)
QTW (0.2 mm)

Beam SizeCavity design
Field calculaLonRF

90 degcathodebeam

coupling caviLes

acceleraLng
cavityNo reﬂecGon to klystronhybridMechanical design and manufacturing

A‐1 RF gun‐ Quasi‐travelling wave side couple RF‐Gun‐ Yb based laser system

Installed RF‐Gun

Chicane for bunch compression
30ps => 10ps

ExisLng DC‐Gun & pre‐buncher

Installed RF gun
Cathode
90 de

g Hyb

rid

Laser port

‐ 10 MeV @ 20 MW is designed value‐ 6 MeV @ 12 MW is maximum power => Phase slip , Large energy spread

IrCe cathodeCathode : Advantage of metal composite cathode(LaB6 or Ir5Ce )JusLn Jimenez, A SystemaLc Cathode Study , Ph.D Thesis, Monterery, California

Low WorkfuncLon (2.8 eV)and enough QE (10‐4)
at room temperature.
• InacLve in air• Recover by heaLng or
laser cleaning•

Best choicefor SuperKEKB 5 nClong Gme operaGon
Physica Scripta. Vol. T71, 39‐45, 1997.
Cathodes for Electron Guns
G. I. Kuznetsov

LifeLme measurement（LaB6 / Ir5Ce）
10
QE‐4
IrCe
LaB6

10‐5
0

5

10

15

20

25

30

35

LifeGme (hour)

Condi&on
ConGnuous pulse laser 200μJ@266nm)
IrradaGon => 2.5 nC emission

40

45

50

CondiGon
HV = 16kV
Vacuum ; 5.8×10‐6 Pa
Cleaning Lme ; 10 min

Quantum eﬃciency improvement
by Laser cleaning

QE

1500
1200

LaMz

900

LaB6
SEM‐EDX

Oxigen
OKsum

Counts1800

Carbon
LaMa

BKa

2100

CKsum OKa

2400

CKa

2700

10‐4

LaLa

Ir5Ce Cathode

600

0
0.01

1.51

2.01

2.51

3.01

3.51

4.01

4.51

keV

Ir5Ce
Carbon

8000

CKa

4000
3000
2000

0.50

1.00

1.50

IrMr

5000

IrMz

6000

CeMa
OKsum

FKa

7000

CeLa

10000

IrMa

SEM‐EDX

11000
9000

Ir5Ce@266nm

1.01

12000

LaB6@266nm
LaB6@532nm

0.51

CKsum OKa

×２０

300

Counts10‐5Lower energy density
is enough to acLvate Ir5Ce

1000
0
0.00

10‐6
0

2.00

2.50

3.00

3.50

4.00

4.50

keV

1000
2000
3000
4000
Energy density of cleaning laser(μJ/mm2)

Non acLvaLon
QE = 5.00×10‐6

×20

Laser cleaning
Max QE = 1.00×10‐45000

No oxidizaLon is observed[SUPER‐KEKB e Linac]
Laser Power ; 233μJ/pulse（λ=266nm）
Target value ; 5nC

5.00

Laser system for A‐1 RF‐Gun

Requirement of laser system for RF‐Gun• Laser energy– 500 µJ UV for Ir5Ce cathode– 50 µJ UV for Ce2Te cathode• 50 Hz, 2‐bunch (96ns spacing)=> Diﬃcult to adopt commerLal products
using regeneraLve ampliﬁer.
=> MulG‐pass ampliﬁer
or Special regeneraLve ampliﬁer• Temporal pulse shaping– ReducLon of energy spread due to longitudinal wakeﬁeld– Rhombus shape for laser injecLon with angle (higher QE)=> Broadband laser crystal (Yb or Ti:Sapphire)• ConLnuous operaLon (limited cost / human resource)– Support cost for commerLal product is very high.
(10‐20万円=1,000‐2,000$/day/person + α (margin) )– No laser system company in Japan.
– Recovering Lme.

Required laser pulse energy
Current laser energy(500μJ)
1.00E-07

Charge( C )Charge(QE=1e-5)@266nm
Charge(QE=1e-4)@266nm
Charge(QE=1e-3)@266nm

Ce2Te

QE=10‐3

QE=10‐4

Oﬄine measurement
S‐polarizaLon
Oﬄine measurement
P‐polarizaLon

1.00E-08

QE=10‐55nC

1.00E-09

1.00E-10
1.00E-06

ATF

Inclined injecLon

1.00E-05

1.00E-04

Laser power ( J )Normal injecLon (old 3‐2)

1.00E-03

1.00E-02

How to generate 2‐bunch• AmpliﬁcaLon Lme of standard regeneraLve ampliﬁer(usually adopted in commerLal product) is around 1 µs.
• Two regeneraLve ampliﬁer (not good)• Large regeneraLve ampliﬁer (built & failed)– Unstable output energy due to low gain.
– Diﬃcult to compensate thermal lens.

• High gain fast regeneraLve ampliﬁer (built & failed)– Diﬃcult to reduce the ghost pulse from ﬁrst bunch due tolimted exLncLon raLo of pockels cell.

• MulG‐pass ampliﬁer (current conﬁguraGon)– More gain is required for the balanced 2‐bunch.

• OPCPA (future candidate)Rhombus pulse shaping for angled injecLon
Pulse shaping is necessary atangled injecGon for higher QE.

Mirror invacuumBeam

One of problem is beam hole in the cavity
is too small. (less than cathode diameter.)Redesign is required.

Energy spread reducLon by pulse shaping
Energy spread of 0.1% is required for SuperKEKB synchrotron injecLon.

15nC

3

t
2.5

Gaussian2

σE/E (%)

5nC 10nC

20nC

1.5

1

t
5nC
10nC
15nC
20nC

Square

0.5

0
0

5

10 5nC electron
15
FWHM (ps)

20
15nC

25

30

Primary beam for positron producLon

Nd‐doped

ProperLes of laser medium

Nd laser system for 3‐2 RF‐Gun

τ〜200μs, 40%○ 4-state laser is easy to operate.
○ High power pump LD is available.
○ Large crystal is available
× Pulse width is determined by SESAM.
(Gaussian)

LD PumpSHG(532nm) 40%
FHG(266nm) 20%
5HG(213nm) 3%

Nd:YVO4
Nd:YAG(808nm)808nm

1064nm

Yb‐doped○ Wide bandwidth => pulse shaping
τ〜900μs, 40%○ Long fluorescent time => High power
SHG(520nm) 40%○ Fiber laser => Stable
Yb‐glass
LD PumpFHG(260nm) 20%○ Small state difference
Yb:YAG(941/976nm)
5HG(208nm) 3%
× ASE
Yb:BOYS
941/976nm
1040nm
× Absorption

Ti‐doped Pump τ=200μs, 40%Pump(808nm)τ〜3μs, 40%
40%

Fluorescence

Nd:YAG
SHG
Ti:Sapphire
808nm
1064nm
800nm
532nm○ Very wide bandwidth○ High breakdown threshold
TW laser is based on Ti‐Sapphire× Low cross secLon
× Short ﬂuorescent Lme => Q‐switched laser is required for pumping

Absorption

Best for RF‐Gun

Material

Nd:YAG

Yb:YAG

Ti:Sapphire

Wavelength

1064nm1030nm

660-1100nm

Fluorescent time

230ms

960ms

3.2ms

Spectral width

0.67nm

9.5nm

440nm

Fourier minimum
Pulse width
Wavelength

2.48ps

165fs

2.59fs807.5nm

941nm

488nm

Spectral width

1.5nm

21nm

200nm

Quantum efficiency

76%

91%

55%

SHG(400nm) 40%
THG(266nm) 20%
FHG(200nm) 10%

Ti:Sapphire laser system for beam monitor.

Yb
laser
system(Present
status)Yb Fiber Laser
Yb Fiber
Oscillator

Yb Fiber
Ampliﬁer

frep=52MHz

Amplitude
modulator x 2

ASE problem

frep=52MHz→10MHz
Yb Fiber
Ampliﬁer x 2(20W + 70W pump)

Fiber strecher& wavelength
selecLon

Pulse picker

Yb PCF Ampliﬁer(70W pump)

frep=10 MHz→50 Hz

λ0→1030 ‐ 1040nm

Yb:YAG laser

Pulse
Compression

Yb:YAG
MulLpass
Ampliﬁer

Yb:YAG
5‐pass Ampliﬁer
×4stage

Yb:YAG
RegeneraLve
Ampliﬁer

Yb:YAG
5‐pass Ampliﬁer

7 mJ @ 1030nm
Wavelength
conversion

Failed

0.7 mJ @ 258nm

Yb Fiber Oscillator

Yb ﬁber oscillator:‐ 30 fs is possible using non‐linear
polarizaLon rotaLon.
‐ 52 MHz is not suitable=> 114 MHz will be installed

Transmission
grating pair←

Remaining problem:‐ LD was someLmes broken.
‐ Bunch structure at higher output power.
=> SESAM is not eﬀecLve.
=> Replace some components.
‐ 1030nm oscillator is not stable‐ 1030nm component of broadband oscillatoris small => large ASE

WDM

Yb Fiber←

Improved items in FY2013:‐ Transmission graLng=> Stable modelock (higher eﬃciency)‐ Super‐invar breadboard=> Improve thermal stability.
‐ Piezo mirror on large lead block=> Reduce vibraLon.
‐ Broadband oscillator (No.2) is stable.

LDYb:YAG ﬁber oscillator
Two 52 MHz oscillators are installed for the underground laser
room.
Second oscillator is very stable

Yb:YAG bandwidth

Intensity [a.u.]

Oscillator 1
Oscillator 2

1000

1010

1020

1030

1040
1050
1060
Wavelength [nm]

1070

1080

1090

1100

Oscillator1: Narrow (Less ASE)
Oscillator2: Broadband (Stable)

Phase stability (sigma)
Oscillator1 : 2.38 deg
Oscillator2 : 0.58 deg = 560 fs

Pulse shaping using strecher

Strecher

Telescopelens

1740-grooves/mm

Measured by streak camera

30 ps

Rectangular‐like
30 ps pulse width
was obtained.

Yb:YAG solid state ampliﬁer• Improvement of heat conducLvity
by Au‐Sn vacuum soldering.
Copper plate

Au‐Sn coaLng

5 Hz =>
25 Hz operaGon was achieved.

Original multi-pass amplifier (5-pass)
To obtain higher gain,=> Higher pumping density⇒ Thermal lens
⇒ Focused type ampliﬁer toavoid thermal lens.

Balanced oﬀset
lens to avoid
damage.

5pass

Laser Diode

4pass

3pass

2pass

1pass

New high gain multi-pass amplifier(10-15 pass x 2 loop)
to simplify the laser
Laser DiodeOUTPUT

INPUT

10-15pass

1pass

←

Issues on Yb based laser system• Yb‐ﬁber oscillator– 1030nm oscillator is not stable.
– Broadband oscillator is very stable => Further ASE reducGon is required.

• Yb‐ﬁber ampliﬁer– Lack of pulse energy =>– LifeGme and stability of PCF ﬁber => Improve the injecLon• Yb‐disk ampliﬁer: (RegeneraLve ampliﬁers were failed)=> MulL‐pass ampliﬁer for 2‐bunch operaLon.
=> More gain is required for balanced 2‐bunch energy.
– 5 Hz => Soldered cryatal => 25 Hz operaGon=> x 2 system => 50Hz before May 2015
– Reduce thermal lens eﬀect and simplify laser system=> Focused type high gain mulGpass ampliﬁer x2+ Non‐focused mulGpass ampliﬁer• Stability improvement– Casing of each block.
– Gas ﬁlled or vacuum laser transportaLon to improve poinLng stability.
– Assemble on one large opLcal table (new laser room).
– Feedback (poinLng / amplitude).
– Increase monitor points (poinLng / power / beam paCern).

Comissioningof A‐1 RF‐Gun

RF voltage
RF power[MW]

Maximum surface
E‐ﬁeld [MV/m]

DAW @ 3‐2

3.5

150

QTW @ A‐1 target

20

120

QTW achieved @ A‐1

1485

DAW type RF gun iseﬀecLve shape for
mulLpactoring?

One week RF ageing
reach this target.

Beam hits anode.
Anode shape should be changed.
(large beam hole)cathodeA‐1 RF gun results
5.6 nC was achieved.
However beam proﬁle is not good.

3 nC beam delivery was achieved.

36

Charge history of A‐1 RF‐Gun (3nC)

QE : 3nC = 14nJ / 300μJ = 4.5×10‐5 (QE)EmiCance measurement
Q scan method
using screen
monitorWire scannerat B sector

beam charge : 0.6nC
beam energy : 30 MeVNormalized emiCance
X : 13.4 +/‐ 5.9 [mm‐mrad]
Y : 8.05 +/‐ 0.47 [mm‐mrad]

Normalized emiCance
X: 95.0 ±27.4 mm‐mrad
Y: 42.0 ±31.1 mm‐mrad(including the beam
posiLon jiCer.)Bunch compression and streak camera

10 psec

Compression at chicane

20 psec

No compression

• RF‐Gun cavity

Summary of issues– Disk and washer (DAW) : very fast RF ageing, 2 MeV is not enough.
– Quasi travelling wave side couple structure :• Lower electric ﬁeld than designed value.
=> Thermal electron gun will recover for positron generaLon in May 2015.

• Cathode– Room temperature Ir5Ce cathode seems best cathode !
– Laser injecLon angle for surface plasmon is eﬀecLve.
– R&D for the QE improvement and cleaning.
– PreparaLon to use alkaline cathode• Laser & control– Nd based laser system : 3‐2 RF‐Gun• Oscillator:• RepeLLon rate

RF synchronizaLon precision is not enough.
10 Hz operaLon => how to upgrade to 50 Hz ?

– Yb based laser system : A‐1 RF‐Gun• Beam transportaLon and diagnosLcs=> next page

– Beam loss in ﬁrst acceleraLng structure (will be solved in May 2015.)– Old streak camera for beam diagnosLcs. (renewed for laser diagnosLcs)– Single cavity RF‐Deﬂector installaLon.

Plans & Schedulefollowing
LINAC group strategy
andRF‐Gun review (last week)• These few months: Schedule– Reconﬁgure thermal gun for positron generaLon– Step by step RF‐Gun RF ageing.
Following the RF‐Gun
reviewer’s comments– New laser system in ground laser room.
• Increase pulse energy from ﬁber laser• Simplify the laser system (new mulL‐pass ampliﬁer)• Next summer:(Postponed the pulse shaping unGl Phase‐III )– Second RF‐Gun (nomal laser injecGon / cavity modiﬁcaGon / cathode change)– Simple Nd ampliﬁer for Phase‐I & II stable injecGon

GR̲32

RF-GunBeamline
Cathode
Laser
Comissioning

SuperK
EKB
InjectionRF-GunBeamline
Cathode
Laser
ComissioningGR̲A1

10 ps gaussian is enough for Phase‐I (1nC) & II (2nC), postponed the pulse shaping unGl Phase‐III
FY2011Q2 Q3

2012 FY2012
Q4 Q1 Q2 Q3
DAW

Ir5Ce

LaB6
Nd Laser1

Q4

2013 FY2013
Q1 Q2 Q3

Q42014 FY2014
Q1 Q2 Q3

Q42015 FY2015
Q1 Q2 Q3

Q4

2016 FY2016
Q1 Q2 Q3

Q42017 FY2017
Q1 Q2 Q3

Q4

2018 FY2018
Q1 Q2 Q3

Ir5Ce
Nd Laser2

DAW
Ir5Ce
Yb Laser1 5Hz

SC-QTW
Chicane
Ir5Ce
25Hz

Phase-1
Phase-2
Phase-3SC-QTW2 SC-QTW3
New IrCe cathodeYb Laser2(ground)Nd Amplifier
Thermal Gun

Yb Laser3(Cryogenic)

1nC
2nC low emittance
4nC low emittanceDesignDevelopment
Installation
Operation

Q4

2019
Q1

Strategy for emiCance preservaLon and energy spread• EmiCance preservaLon– Alignment : IniLal alignment / ConLnuous monitor / AcLve
mover / Beam based alignment
0.3 mm mis‐alignment tolerance for 2 nC (unLl Phase‐II)
0.1 mm mis‐alignment tolerance for 5 nC (Phase‐III)=> shorter bunch (5 ps) is required for 0.3mm
mis‐alignment– Oﬀset injecLon compensate the transverse wakeﬁeld(RF Deﬂector will be installed for beam diagnosLcs for oﬀset
injecLon)• Energy spread– 0.1 % is required for SuperKEB injecLon– 10 ps gaussian pulse is enough for 2 nC (unLl Phase‐II)– Laser pulse shaping is only required for Phase‐III– Bunch compression to 5 ps is required for Phase‐III dependingon the mis‐alignment.

Beam line will be upgrade on up and down.
Thermionic DC gun will be installed to upper beam line.

10 nC
for positron primary

70 MeV
Acc.tubebuncher

prebuncher

SHB2

SHB1

Energy slope
Chicane20 psec

30 MeVBunch
20 pseccompression

Acc.tube

RF gun

5 nC
Low emiCance

Thermionic
DC gunReconﬁguraLon of A‐1 injector area

KL_A1_B

KL_A1_A

RF‐Gun2

Second RF gun on the 45 degree line

Normal laser injecGon

Angled laser injecGon

Studies on‐ Improved RF‐Gun cavity‐ Normal laser injecLon‐ Cathode change including alkaline cathodeSecond Side coupled Quasi‐travelling wave RF‐Gun

Second RF‐Gun under brazing

Current cathodeCondiLoning progress was too slow.
Frequently brake down is big problem.
Cathode rod contact?
Cathode material ﬁxaLon?
Cathode material spuCering due to laser?
We have to separate causes of brake down.
1. Cavity condiLoning, used dummy cathode rod
with out cathode material (all Cu).
2. Replace new cathode rod with material (newﬁxaLon is shrinkage ﬁt).
3. For reduce mulLpactoring eﬀect, anothercathode cell design is required.

New cathodeshrinkage ﬁt

Simplify and stabilize our laser system without pulse shaping
ExisGng laser system

114.2 MHz
Menlo

Yb‐doped ﬁber
oscillator withTransmission graLng@ 1030 nm

PCF Yb‐doped ﬁber
ampliﬁer

Pulse
pickerYb:YAG thin‐disk
mulLpass ampliﬁer(25 Hz x 2)

@ 1064 nm

Simple Nd ampliﬁer laser system without pulse shaping
according to RF‐Gun reviewer’s comment
LIEKKI Yb‐
doped ﬁber
ampliﬁer
Op&lab YDFA‐r‐40‐S,
Output power of 20W\3,500,000

Pulse
pickerGrating pairYb ﬁber
Oscillator
SpaLally dispersed

CommerGal Nd:YAG rod
mulLpass ampliﬁer (10 Hz => 50 Hz)

Fiber Ampliﬁer@1030 nmFiber Ampliﬁer@1064 nmStrecher for Yb:YAG & Nd:YAG
Yb:YAG

Nd:YAG

Center wavelength1030 nm

1064 nmGain spectrum
width

~2 ns

~0.5nsDistance of theStretcher to 30 ps

1.5 m

6 m (×4)

Gain spectrum of Yb:YAG
Distance ofgrating pair30 psGrating pair
2.0nm

Improvement of ﬁber collimaLon

PCF ﬁber damage is one issue => Improve the ﬁber collimaLon• Fiber coupler• Cooling system
Fiber coupler in ERL• Drum Lens

Higher output pulse energy from ﬁber ampliﬁer=> Reduce number of stages of Yb:YAG mulL‐pass ampliﬁer

Temperature dependence of Yb:YAG• Improvement of thermal and emission property(Thermal lens eﬀect)(ExcitaLon density)

GM+He
10 W/m/K , dn/dT = 8ppm/K @ 300K
25 W/m/K , dn/dT = 3ppm/K @ 150K
↑150K 1/6 Thermal lensSame gain @ 1/3 excitaLon density→↓
150K => 1/20 thermal lens
300K P/P0 = exp(g0z) 〜2
150K→ g = 7 [cm‐1]

PerLer300K
30kW/cm2

• These few months: Schedule– Reconﬁgure thermal gun for positron generaLon– Step by step RF‐Gun RF ageing.
Following the RF‐Gun
reviewer’s comments– New laser system in ground laser room.
• Increase pulse energy from ﬁber laser• Simplify the laser system (new mulL‐pass ampliﬁer)• Next summer:(Postponed the pulse shaping unGl Phase‐III )– Second RF‐Gun (nomal laser injecGon / cavity modiﬁcaGon / cathode change)– Simple Nd ampliﬁer for Phase‐I & II stable injecGon

GR̲32

RF-GunBeamline
Cathode
Laser
Comissioning

SuperK
EKB
InjectionRF-GunBeamline
Cathode
Laser
ComissioningGR̲A1

10 ps gaussian is enough for Phase‐I (1nC) & II (2nC), postponed the pulse shaping unGl Phase‐III
FY2011Q2 Q3

2012 FY2012
Q4 Q1 Q2 Q3
DAW

Ir5Ce

LaB6
Nd Laser1

Q4

2013 FY2013
Q1 Q2 Q3

Q42014 FY2014
Q1 Q2 Q3

Q42015 FY2015
Q1 Q2 Q3

Q4

2016 FY2016
Q1 Q2 Q3

Q42017 FY2017
Q1 Q2 Q3

Q4

2018 FY2018
Q1 Q2 Q3

Ir5Ce
Nd Laser2

DAW
Ir5Ce
Yb Laser1 5Hz

SC-QTW
Chicane
Ir5Ce
25Hz

Phase-1
Phase-2
Phase-3SC-QTW2 SC-QTW3
New IrCe cathodeYb Laser2(ground)Nd Amplifier
Thermal Gun

Yb Laser3(Cryogenic)

1nC
2nC low emittance
4nC low emittanceDesignDevelopment
Installation
Operation

Q4

2019
Q1