Accelerator Lab of Tsinghua University

Activities of Accelerator lab, Tsinghua Univ. on ILC-related

researches

Presented by Qingzi XingAccelerator lab, Dep. Engineering Physics, Tsinghua Univ.

Nov. 6th, 2007, IHEP

Accelerator Lab of Tsinghua University

A preliminary Thomson Scattering X-ray experimental setup

Field tuning and HOMs measurement of the 9-cell ICHIRO copper cavity model

SC Deflecting Cavity for ultra-fast X-ray pulse

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Accelerator Lab of Tsinghua University

Positron Source (Compton Scheme)

From KURIKI Masao, ILC School 2006

A preliminary Thomson Scattering X-ray experimental setup

Laserwire components

From Marc Ross, ILC School 2007 3

Electron and laser photon interaction: Positron source & beam diagnostics

Accelerator Lab of Tsinghua University

A preliminary Thomson Scattering X-ray experimental setup

Ocilator

DAQ

Linac

Quadrupole

Faraday Cup

B1

CCD CameraComputer

Collimeter & Shielding

Detector

Laser

Triode Electron Gun

YAG or OTR foil

Slit

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Accelerator Lab of Tsinghua University

The experimental setup scheme

Parameters of Preliminary Thomson

scattering experiments

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Accelerator Lab of Tsinghua University

The measurement result for X-ray from MCP

MCP(based on flange)

Valve

CF25 Flange

To Pump

Spare

CF50(35) FlangeAbsorption flakes

Thomson scattering X-ray

X-ray Mulitlayer(angle of reflection is about

50mrad)

6 ns

1.7x104/pulse

X-ray photon

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Accelerator Lab of Tsinghua University

A Proposed Thomson Scattering X-ray Source (Using 60~100MeV Linac)

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Accelerator Lab of Tsinghua University

9-cell superconducting ICHIRO copper cavity model provided by KEK.

Field flatness measurement system of the ICHIRO cavity.

Field tuning and HOMs measurement OF the 9-cell ICHIRO copper cavity model

Relative axial electric field of the TM010_PI mode obtained from the bead-pull measurement. The field flatness is 53.2% before tuning, and 97.2% after tuning with the PI mode freq. of 1298.2 MHz. 8

Accelerator Lab of Tsinghua University

The change of the field and the spectrum due to the perturbation of individual cells, based on the analysis of the equivalent circuit model .

(a) Perturbation of cell No. 1

(b) Perturbation of cell No. 2

(c) Perturbation of cell No. 3

(d) Perturbation of cell No. 4

(e) Perturbation of cell No. 5

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Accelerator Lab of Tsinghua University

Calculated (Left) and Measured* (Right) dispersion curves of the monopole and dipole modes

* ▲ and indicates the different polarization in the dipole passbands.

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Accelerator Lab of Tsinghua University

Modef (GHz)

Calculated

f (GHz)

Measured

R/Q① (Ohm/cmn)

Calculated

R/Q① (Ohm/cmn)

MeasuredTM010-9 1.299249 1.298271 1125.75 974.02

TE111-7a 1.715894 1.728774 6.91 2.63

TE111-8a 1.737056 1.752081 3.76 3.49

TM110-5a 1.926031 1.924716 14.20 7.91

TM110-4b 1.939577 1.939012 13.11 1.01TM011-6 2.169293 134.42TM011-7 2.175969 184.35TM111-1 2.448334 30.49TM111-2a 2.454574 2.456481 20.01 7.55

FM and HOM data calculated and measured①: n=0 for monopoles, n=2 for dipoles; a, b indicate polarizations.

2 2

0 00 0 0

1 1 2 2/ [( cos ) ( sin ) ]

2

L L

z zn

z zR Q E dz E dz

b f W

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Accelerator Lab of Tsinghua University

Relative frequency shift of the TE111_PI mode 1.5cm off the axis obtained from the bead-pull measurement using a dielectric (Left) needle ( d = 1.4 mm, l = 16.6 mm ) and a metal (Right) needle ( d = 0.31 mm , l = 20 mm ) as perturbation objects. |E| (Up) and Ez (Down) are mainly measured.

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Accelerator Lab of Tsinghua University

SC Deflecting Cavity for ultra-fast X-ray pulse• Deflecting Cavity can be used to generate sub-picosecond’s X-ray

pulses. The scheme is shown below.

• Proposed at LBNL, ANL… Collaboration

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x

RF kick

Crab crossing

From Andrei Seryi, ILC School 2006

Hard X-ray pulses by electron bunch manipulation and x-ray compression

Accelerator Lab of Tsinghua University

2 Cell Cavity design for LBNL

B_peak •Peak magnetic field @ iris

Waveguide damper for LOM and HOM

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Accelerator Lab of Tsinghua University

0.5 1 1.5 2 2.5 3 3.5 4

x 109

10-3

10-2

10-1

100

101

102

103

f (Hz)

Z 0 ||

(k

)

iris35, end45iris40, end45threshold

0.5 1 1.5 2 2.5 3 3.5 4

x 109

100

101

102

103

104

105

f (Hz)

Z 1

(k

/m

)

2 ca

vitie

s, v

ertic

al

Transverse Impedance

straight wgthresholdwg with step

2 M /m

working mode

mode in wg@bp

TE111

TE121

0.5 1 1.5 2 2.5 3 3.5 4

x 109

100

101

102

103

104

f (Hz)

Z 1

(k

/m

) 2

cav

ities

, hor

izon

tal

Transverse Impedance

TM110

, unwanted

TE111

2 M /m

Storage ring needed to damp the LOM and HOMs

Waveguide for LOM, HOM and unwanted Dipole mode at x-direction

Impedance below threshold

Impedance after Waveguide Damping

Longitudinal Impedance

Transverse Impedancehorizontal vertical

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Accelerator Lab of Tsinghua University

Holes for “Bead-pull”

MAFIA Measured

f / GHz Q f / GHz Q

1.03065 10462 TM01 1.0300 4440

1.03749 10443 TM01 1.0370 4600

1.50065 12842 TM11 1.4995 5400

1.52719 13418 TM11 1.5262 4400

2.03292 14935 TM21 2.0314 7000

2.03557 15014 TM21 2.0345 6240

Q is lower because of

Surface roughness

Cell assembly

Cold Test on Al model

Parallel wire to make a “bead”

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Accelerator Lab of Tsinghua University

Cold Test on Al model for Damping

Cavity with/without Waveguide damping

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Accelerator Lab of Tsinghua University

Bunch Length Measurement by RF Deflecting Cavity

Photo-CathodeRF Gun

Linac Linac QuadrupolesRF Deflecting

Cavity Flag

Photo-CathodeRF Gun

RF DeflectingCavity Flag

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Accelerator Lab of Tsinghua University

different configurations

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Accelerator Lab of Tsinghua University

3-Cell Deflecting Cavity Design

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Accelerator Lab of Tsinghua University