Mitsuru Uesaka- Laser plasma cathode by 12 TW, 50 fs laser and its application to radiation chemistry

8/3/2019 Mitsuru Uesaka- Laser plasma cathode by 12 TW, 50 fs laser and its application to radiation chemistry

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Laser plasma cathode by 12 TW, 50 fs laser

and its application to radiation chemistry

Mitsuru Uesaka

Nuclear Engineering Research Laboratory ,

University of Tokyo

June 26, 2004

International Symposium on

Ultrafast Accelerators for Pulse Radiolysis


2/22

Two New Accelerator Rooms

Compact Medical Linac/Laser Plasma Beam Source

Linac Building(1st Floor)

Fusion Blanket Building(1st Floor)

Compact Medical Linac

Laser Plasma Beam Source


3/22

12TW 50fs Laser Plasma Beam Source

Amplifier 2

Amplifier 1

Clean Room

Regenerative amplifier

Pre-amplifier

YAG lasers

Laser system

Compressor chamberExperimental area


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0.0 25.0 50.0 100.075.0

[mm]

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.0

90

180

270

Energetic electronsup to ~40MeV

Spotsize D~8.1mm (FWHM)

Typical Image of Electron Beam Generation(Experimental Results: Signals on I.P.)

(180mm from gasjet)He 2.8x1019cm-3, Laser ~4.8TW

Experimental Set-up

Reference:T.Hosokai,et al.,Phys Rev.E 67,036407 (2003)

0 20 40 60Electron Energy [MeV]

PIC simulation

1 0-2

10-3

10-4

10-5

Ele

ctr

on

Dis

trib

ut

ion

[ar

b.u

n]

Electro

nSignal[arb.un]

e-spectrum

a b c

Laserpulse

-1~1ns (Main Pulse)b: 1ns~3ns c: 2ns~5ns


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Pump-and-probe Experiment Using Plasma Cathode at University of Tokyo


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Pump and probe Experiment Using Plasma Cathode at University of Tokyo

Fs laser

Probe laser

50fs(FWHM)

Pump EB

40fs(FWHM)

Supersonic

He gas jet

Sample

Photo-detectors

for measuring

light absorption

Fig. Schematic diagram of pump-probe

experiment using plasma cathode

Dominant factors for time resolution

EB for pump : 40fs(FWH Laser for probe : 50fs(FWH

Timing jitter : ~0fs

Desynchronization in sample : ~1ps/mm

Current problems to be solved Electron beam

- Energy spread : 100%


18/22

Big Advantage of Laser Plasma Accelerator

for Pump-and-probe analysis

Synchronization is perfectly passive without any electronics.

12TW Laser

Beam Splitter Optical Delay

Laser Plasma Cathode

Laser(50fs)

Electron Bunch(40fs)

No timing jitter and drift between laser and secondary beam.Femtosecond time-resolved analysis is surely available

after the bean quality and stability are upgraded.


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Summary of Synchronization

1. Laser vs Accelerator Synchronization System via Electronics

Picoseconds time-resolution

2. Laser Seeded Staged Accelerator

Femtoseconds time-resolution

Available for multibunches

3. Laser Plasma Accelerator

Beam Splitter enables even Attoseconds time-resolution

After Stable and reliable beam generation and diagnosis

are established


20/22

Tens Femtosecond or Quasi Monochromatic Electron Single Bunch


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Tens Femtosecond or Quasi-Monochromatic Electron Single Bunch

by Laser Plasma Cathode (RAL, LBNL, LOA, AIST, U.Tokyo at AAC2004)

100

101

102

103

104

600 700 800 900 1000 1100 1200 1300

Intens

ity

(arb.unit)

Wavelength (nm)

1st-Stokes

Laser Wavelength

Tens femtoseconds

Quasi-

monochromatic

U.Tokyo(cal)

AIST(exp)

AAC 2004 Experimental Results Laser-Plasma Accelerator WG


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AAC 2004 Experimental Results Laser Plasma Accelerator WG

2

MeV

Self-

trapped

1x101

8 cm-3

2TW0.8

mkm

SM-

LWF

A

KERI

Glass

capillary

100 MeV

Self-

trapped

6x1016 cm-3

30TW1.06 mkm

LWFA

Osaka

University

2 TW

beam for

LIPA

injector

Ponderom

otive

channel

Integrated

over 90

shots

spectrum

Channel

40 MeV20 MeV38 MeV40 MeV7 1 MeV

2 pC

78 2

MeV

20 pC

86 2 -150

MeV

300 pC

>17015

MeV, 500

pC,

Energy

Gain

Self-

trapped

Optical

Injectionioniz.

12 MeV

external

Self-

trapped

Self-

trapped

Self-

trapped

Self-

trapped

Self-trappedInjector

type

1.4x1020

cm-31x1019 cm-3

1x1016 cm-3

1.8x1019

cm-3.1.5x1020

cm-32x1019 cm-

3

2x1019 cm-3

6x1018 cm-3Plasm.

Density

20TW0.8

mkm2.x10

19

W/cm2W0

=5 mkm,,

23fs

10TW1.06

mkm3x10

18

W/cm2W0

=12 mkm,

500s

1TW10.3+

10.6.mk

6TW0.8 mkm

1x1019

W/cm2W0

=6

mkm,50fs

2TW 0.8mkm

5x1018

W/cm2W0

=5

mkm,50fs

16TW0.8

mkm ,1x1

018

W/cm2W0

=25

mkm,40fs

8TW0.8

mkm,1x10

19

W/cm2W0

=7 mkm,

55fs

30TW0.8 mkm,

3x1018

W/cm2,

W0=18

mkm, 30fs

Laserparrs

SM-

LWFA

SM-

LWFA

PBWASM-

LWFA

SM-

LWFA

SM-

LWFA

SM-

LWFA

SM(for-

ced)LWFA

Scheme

JAERINRLNeptune,

UCLA

University

of Tokio

AISTRAL-

alphaX

LBNLLOA

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Mitsuru Uesaka- Laser plasma cathode by 12 TW, 50 fs laser and its application to radiation chemistry