design and experimental considerations for multi-stage laser driven particle accelerator at 1μm...

Design and Experimental ConsideratioDesign and Experimental Considerations for Multi-stage Laser Driven Particle ns for Multi-stage Laser Driven Particle Accelerator at 1Accelerator at 1μμm Driving Wavelengthm Driving Wavelength

Y.Y. Lin(林元堯） , A.C. Chiang（蔣安忠） , Y.C. Huang（黃衍介）

Department of Electrical Engineering, National Tsing Hua University, Hsinchu,300, Taiwan

ORION Workshop Feb.18-20,2003

NTHU Relativistic Photon-NTHU Relativistic Photon-Electron Dynamics LaboratoryElectron Dynamics Laboratory

OUTLINE

• Motivation

• Review on the multi-stage CO2-laser-acceleration Project at ATF BNL

• Scaled to 1-μm Wavelength

• A Proposed Muti-stage Experiment at ORION


MOTIVATION

• 10-μm Wavelength using 70 MeV beam at ATF BNLa. large structure size

b. high-power CO2 laser available at ATFc. easier for alignmentd. good for proof-of-principle experiment

• 1-μm Wavelength using 350 MeV beam at ORION a. higher material damage field with 1-μm wavelength b. higher laser damage threshold with ~100 fs laser pulse c. smaller phase slip with 350 MeV beam d. smaller beam size for electron transmission aperture e. higher acceleration gradient f. solid-state laser stability and efficiency

NTHU Relativistic Photon-Electron NTHU Relativistic Photon-Electron Dynamics LaboratoryDynamics Laboratory

Lens-array structure (I): Accelerating Stages

2/3*z0

f=5z0/3=3.81cm

24 cm = 15cm x 16

1.5cm

Each lens’ temperature is varied independently by a TE cooler

Electron transit on each lens is 100μm in diameter


Ref: E.J. Bochove, G.T. Moor, ad M. O. Scully, Phy. Rev. A, Vo. 46, No. 10 ,pp. 6640-53,Nov. 1992

CO2-laser-acceleration Project at ATF BNL

Laser beam waist ~280μm

Lens-array structure (II): System setup of the multi-stage lens array accelerator structure

TEM00

TEM01

Mode filter

f=10”

f=2”f=3”f=0.5”

Accelerator cell

24 cm 5.32 cm 9.19 cm 2 cm 120 m

100 m

120 m

30.4

8 cm

Si detector (movable)

48.15 cm

W0= 280 m

W0= 104 m

W0= 2000 m

Phase offset

Iris & mirror

iris

Chamber

E_max=132M V/m

Energy gain=240 keV

NTHU Relativistic Photon-Electron NTHU Relativistic Photon-Electron Dynamics LaboratoryDynamics Laboratory




Numerical simulation for 1st stage


Numerical simulation for 2nd stage


Lens-array structure (III): Energy Gain along axisDamage threshold: 0.45 J/cm2 for ZnSe and 1.2 J/cm2 for CVD diamond

Total energy Gain over 24 cm: 240 keV (ZnSe)

400 keV (CVD diamond)

NTHU Relativistic Photon-NTHU Relativistic Photon-electronics dynamic Laboratoryelectronics dynamic Laboratory


Lens-array structure (IV): The Design Parameters for the Multistage Accelerator at ATF BNL

Single-stage length 1.5 cm

Total linac length 24 cm

Number of accelerator stages 16

Electron transit hole diameter 100 m

Laser beam waist in each stage 280 m

Laser damage threshold (ZnSe) 2.25 GW/cm2(0.45 J/cm2)

Laser wavelength 10.6 m

Laser Mode TEM01

Phase tuning by temperature π over 93C

Total energy gain 240 keV



Lens array structure at (V): Temperature phase tuning

laser

HeNe

B.S.

B.S.Mirror

Mirror

L1: ZnSe lens temperature controlled by TE cooler

L1

TE cooler

lensdkTnT 0)()(

Si detector(det210)

iris



Lens array resonator structure at (V): Phase tuning over

temperature experiment

CdT

dn

ndk

/1014613.2 4

0

,where d is the thickness of lens(~0.98mm), and λ0 is the wavelength of He-Ne laser in vacuum (~632.8nm)

For 10.6 um CdT

dn /106.5 5



Or CdT

d /9.1

Scaled to 1 m wavelength at ORION

1. Formation/coherence length ~ γ2 λ2. Acceleration field ~ √(damage threshold)

ORION ATF

Wavelength 1μm 10.6 μm

Beam energy 350MeV

(small phase slip and beam size)

70MeV

Laser pulse width 100 fsec 200 psec

Damage threshold 2J/cm2 0.45J/cm2

advantage suitable for high-gradient experiment

Suitable for proof-of-principle experiment


Lens-array structure (I): The Design Parameters for the Multistage Accelerator

High-gradient, small structure design

Low-gradient, large structure design

Single-stage length 1 mm 5 mm

Total linac length 1.3 cm 6 cm

Lπ( Coherent length ) 9.8 mm 260 mm

Number of accelerator stages 13 12

beam waist (W0) 18.4 m( with zr=1mm)

87.3 m ( with zr=2.25cm)

Laser damage threshold 2J/cm2 2 J/cm2

Laser wavelength 1 m 1 m

Laser Mode TEM01 TEM01

Total energy gain 3.6 MeV 4MeV

Acceleration gradient 280 MeV/m 66 MeV/m

A Proposed Muti-stage Experiment at ORION



Quantities to be Measured

1. Coherent transition radiation by tuning the optical phase on individual lens wake field impedance

2. Multistage phase control

3. Acceleration energy gain and gradient



Energy 350MeV

Pulse length 100 fsec

Particles ~109

Energy Spread 0.1%

Normalized Emittance ~1 mm-mrad

Timing Stability 100 fsec

Energy Stability 0.1%

Pointing Stability 1μm

Electron beam parameter

Summary Table of Laser Acceleration Project at ORION (I)Summary Table of Laser Acceleration Project at ORION (I)


Pulse Energy 0.3 mJ

Wavelength 1 μm

Pulse width 100 fsec

Mode TEM10

Timing Stability 100 fsec

Pointing Stability 1μm

Laser beam parameters


Summary Table of Laser Acceleration Project at ORION (II)Summary Table of Laser Acceleration Project at ORION (II)

Energy Spectrometer 0.1%

Charge 10 pC/pulse (108 electrons)

Positioning resolution 1 μm

Emittance resolution 0.05 μm rad

Pulse timing resolution

< 0.1 psec


Electron Beam Diagnostics

Laser Beam Diagnostics: power, pulse width, wavelength etc.


Summary Table of Laser Acceleration Project at ORION (III)Summary Table of Laser Acceleration Project at ORION (III)

Summary• The 1 MeV/m Multi-stage CO2-laser-acceleration Project at ATF BN

L is a proof-of-principle experiment for vacuum acceleration

• ORION facility is suitable for high-gradient, small-size vacuum acceleration.

• With 350 MeV beam, 1 μm wavelength, and 100 fsec laser pulse width, an acceleration gradient of 280 MeV/m can be obtained near the material damage.

• The electron energy gain from the proposed 14 accelerator stages is 3.6 MeV over a overall accelerator length of 1.3 cm.


design and experimental considerations for multi-stage laser driven particle accelerator at 1μm...

Documents