experimental results of x-ray generation via laser compton … · 2010. 6. 24. · •positron...
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RRCAT, Indore, 11 March 2010
Ryunosuke KurodaNational Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
Experimental results of XExperimental results of X--ray generationray generationvia laser Compton scatteringvia laser Compton scattering
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FEL
Compact S-band linac
Laser Compton gamma-ray experiment(NRF, gamma-ray imaging)
Storage ring TERAS
Storage ring NIJI-IV
Positron Beam linePositron Beam line
Laser Compton X-ray source
Accelerator Facility at AISTAccelerator Facility at AIST(nearby KEK in Tsukuba)(nearby KEK in Tsukuba)
Introduction
Focus!Focus!
400 MeV linac(since 1978)
•Positron annihilation lifetime spectroscopy
New
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X-ray wave length
)cos1(2)2/1(
2
2220
φγθγλλ
−++
≅K
IcmeAK e 092
0 1085.0/ λ−×≈=
Laser Undulator Radiation
( )( ) 2
0
0
0
)cos(1cos1
cos1
cmE
EE
γφθθβ
φβ
+++−
+=
Scattered X-ray energy
φ
θ
Laser
Electron beam
γ m0c2
X-ray (λ (E))
(λ0 [µm] (E0[eV]), I [W/cm2] )High Power Laser
Scattered X-ray
High Energy Electron Beam
Interaction between high energy electron beam and high power laser
LCS XLCS X--ray sourceray source•Short pulse•Energy tunability•Quasi- monochromatic•Small source size•Good directivity •Good polarization•Compact system …etc
Principle of Laser Compton Scattering (LCS)
Many benefits!
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Application SpaceApplication SpaceLaser Compton Scattering (LCS) hard X-ray Source at AIST
Cs-Te
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YVO4ps-Osc
To modulator
1/4λPockels
cell
AOM
100pulse
CW mode-lock
RF amp. AWG
dump
OSC pulse picker
Pre Amp. & Pulse Modulator
FI
X 2 stage
Single pass G=10
Amplifiers & frequency converterFrom modulator
Flat pulse
AM pulse
SHG FHGYAG amp
1st order To amp.
25MHz,250MS/s14bit
YAG Pre. Amp.
79.3 MHz
KTP BBO
0.7W~0.8W
15mW
150mW 10mW
10Hz100 pulses
Diagram of compact UV laser system for rf gun(In order to generate single and multi-bunch electron beam)
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AOM1m
0.7m
AMP
Pre-AMP
PCConversion Crystal
Oscillator
UV laser statusAll solid-state and compactPulse energy: 10 µJ × 100 pulse/ macro pulsePulse width : 10ps(FWHM)Pulse number: 1 – 100 pulses
1m
We can arbitrary generate a single pulse and multi pulses (100 pulses).
Compact UV laser system for rf gun
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BNL-typeRF-gun
Evaporation Chamber at KEK
After evaporationMo plug
Compact Cs-Te cathode
load-lock system
Delivering unit
(in Collaborating with KEK and Waseda Univ.)
Energy:4 MeV (40MeV at linac out)Bunch charge:1 nCBunch length: 3 ps (rms) Bunch number: 1 – 100
(Bunch spacing: 12.6 ns )Repetition rate:10Hz (Max 50Hz)
Electron beam status at rf gun out
Cs-Te photocathode rf gun
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Q-switched Nd: YAG laser
10Hz
Q-switched Nd: YAG laser
50Hz
λ/2
PBS
Ti: SA
PC
PBS
AP
G
Stretcher
PBS
PBS
FR
G
G
OSC.Q-rayQ-ray10Hz
7W~9W Regen
Pre. AMP.
Main AMP.
Compressor
40mJ
300mJ
7W (700mJ)
200 ps
Pulse pick up @10 Hz
60 mJ
200 mJ
Laser StatusWavelength: 800 nmPulse energy: 100-140 mJPulse width: 100 fs(FWHM)
10Hz
4W
PD 79.3MHz → PLL circuit
SESAM(PZT)
OC 5W MillenniaOSC.
79.3 MHz
200 mW
50 fs
Vacuum pipe
1200gr/mm21200gr/mm2
12480gr/mm2
Collision Laser (CPA Ti:Sa laser) for single collision LCS
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fiber
Klystron
ps-laser
To rf gun laser
fs-laser
To CPA Ti:Sa laser system
Directional Coupler
Master Oscillator2856MHz
PD
2856MHz
To gun & Linacs
79.3 MHz
79.3 MHz
2856 MHzDrift compensator
Timingstabilizer
36th harmonics(2856MHz)
Timingstabilizer
Drift compensator
・Two lasers are synchronized to the master with 36th harmonics of their mode-lock frequencies.・Relative timing jitter between the master and the laser is < 10fs.
(F. Sakai, Proceedings of SPIE, 5194, 149-156 (2003)
(Drift <1ps)
This synchronization system has been accomplished in order to generate 150 fs LCS X-ray in FESTA project in collaborating with SHI.
Timing synchronization system (Low-jitter)
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0.2%Energy spread
40/30 µmBeam size (σx/σy)3 psBunch length (rms)1 nCBunch charge/bunch
20 ~ 42 MeVElectron EnergyTW TW Ti:SaTi:Sa Laser beam (CPA)Laser beam (CPA)
30 µmBeam size (σx/σy)100 fsPulse width (FWHM)
140 mJEnergy/pulse800 nmWave length
Electron beamElectron beam
3 ps
150 fs
Pulse width (rms)
~106 /s (max) @10Hz~20 keV90
~107 /s (max) @10Hz10 ~ 40 keV(tunable)165
Number of PhotonsMax photon energy
Collision angle (φ)
XX--ray beamray beamApplication to biological and medical research
in-line phase contrast imaging, K-edge imaging(because of quite small size of X-ray source about 30~40 µm)
Present beam status (single pulse collision – single pulse X-ray)
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1 Experimental results of in-line phase contrast imaging
2 Experimental results of K-edge imaging
I want to easily introduce applications to biological & medical uses
with our LCS X-ray source
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Sample 1 : lumbar vertebra of ratSample 2 : Hind limbs of Ovariectomized mouse (OVX*)
and Normal mouse *OVX mouse is female mouse whose ovary is extracted
and it forcibly make osteoporosis (bone disease).
X-ray energy : 30 keV
Detector : Blue Imaging Plate (IP)
Exposure Time: 30 min (18000pulse)
2m1m0~750mm
Be Window (30mmφ)SampleIPLaser Compton Scattering
X-ray Source
Experimental SetupIn Collaborating with Ibaraki Prefectural University of Health Sciences in Japan
H. Ikeura-Sekiguxhi, R. Kuroda et al., APL 92,131107 (2008)K. Yamada, R. Kuroda et al., NIMA (2009)(accepted)
InIn--line phase contrast imaging for biological applicationline phase contrast imaging for biological application
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Micro- focus X-ray tube(80kV)
Results of in-line phase contrast imaging①lumbar vertebra of rat ②Hind limbs of normal and OVX mouses
5mm
Normal
LCS X-ray source can realize more contrast enhancement than X-ray tube!
Comparison
Contrast enhancement
OVX
Absorption PhaseContrast
Distance between sample and detector40mm 750 mm
We can observe the bone erosion of OVX mousewhich is the initial symptom of osteoporosis !
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Samples: Sample1: Resolution chartSample2: Rabbit ears with iodinated contrast media (K-edge:33.17 keV)
Exposure time of 1 frame: 3ps (rms) @ single shot, 30 ps @10 shot
Detector: Real time camera (HARP) with X-ray II
2m
Be Window (30mmφ)
Specimen
Detector
Laser Compton X-ray Source
K. Yamada et al., ICFA Workshop "Compton Sources for X/γ Rays: Physics and Applications“, Italy, September 2008
In Collaborating with Prof. Mori Group at National Cardiovascular Center in Japanin order to research the new diagnosis for the initial symptom of the blood vessel disease
(such as diabetes)
K. Yamada, R. Kuroda et al., NIM A 608, pp. S7-S10 (2009)
K-edge imaging for angiography
using laser Compton X-ray source @AIST
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30 frame/sec
(X-ray is 10Hz)
1 frame: 3ps single shot X-ray
1 frame/sec
1 frame: 30 ps X-ray (10 shot)
1 frame/sec
1 frame: 30 ps X-ray (10 shot)
Real time imaging with picosecond (ps) X-ray pulse
Rabbit ear (iodine)Resolution chart Resolution chart
Single shot:250μm
10 shots :125μmResolution Achieved spatial resolution of
single shot imaging is 480µm !(System optimization is not completed)
10mm
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Summary
・Present status of the hard X-ray source via LCS (single pulse X-ray)Max. X-ray energy : ~40keV (electron beam energy: 42MeV)Photon number : >107 photos/s @ 10HzQuasi-monochromatic, short pulse
・Biological and medical application have been started.Preliminary experiment of in-line phase contrast imaging and K-edge imaging was successfully performed using single-collisionLCS hard X-ray
Now, we are upgrading our system to increase X-ray yields up to 2 ×1010/s with Multi-collision LCS scheme. In near future, we will successfully upgrade our system for the biological and medical uses.
Laser Compton scattering hard X-ray source based on S-band linac
Thank you
for your attention !