and coherent THz sources on the basis of S-band S

Transcription

1 Development of LCS X-rays X and coherent THz sources on the basis of S-band S compact linac at AIST R. Kuroda 1 H. Toyokawa 1, E. Yamaguchi 1, M. Kumaki 4, M. Yasumoto 1, H. Ikeura-sekiguchi 1, E. Miura 1, K. Yamada 1, F. Sakai 2, K. Mori 3 1 National Institute of Advanced Industrial Science and Technology (AIST), Japan 2 Sumitomo Heavy Industries, Ltd (SHI), Japan 3 Ibaraki Prefectural University of Health Sciences, Japan 4 RISE, Waseda University, Japan Contents 1. Introduction of S-band compact linac at AIST 2. Laser Compton scattering (LCS) X-ray source and its applications 3. Coherent THz radiation source and its applications 4. Summary 1

2 Where? (located near KEK in Tsukuba, Japan) KEK Tsukuba JAPAN AIST National Institute of Advanced Industrial Science and Technology AIST is one of the largest national research institutions in Japan. About 2,500 Ph. D researchers are working for cutting-edge R&D in wide research fields such as life science, information technology, environment technology, nanotechnology, Geological survey, Measurement Technology etc. Accelerator group is very small group about 10 peoples. 2

3 Storage ring TERAS Laser Compton gamma-ray experiment (NRF, gamma-ray imaging) China-Korea-Japan Joint Workshop on electron/photon sources and applications, Introduction Accelerator Facility at AIST (nearby KEK in Tsukuba) 400 MeV linac (since 1978) Storage ring NIJI-IV FEL Focus! New Compact S-band S linac Laser Compton X-ray source Coherent THz radiation source Positron Beam line Positron annihilation lifetime spectroscopy 3

4 China-Korea-Japan Joint Workshop on electron/photon sources and applications, S-band compact linac Application space Klystron Ti:Sa Laser e- beam Electron beam UV Laser RF gun & 3m LINAC(1.5m 2) 10 m Energy ~42 MeV Bunch charge 1 3 nc Bunch length: sub ps - 3ps (1σ) Bunch number: (Bunch spacing: 12.6 ns ) Repetition rage 10Hz - 50Hz All components are installed in one middle size room (10m 10m) 4

5 Laser Compton scattering X-ray source 5

6 Principle of Laser Compton Scattering (LCS) Interaction between high energy electron beam and high power laser High Power Laser High Energy Electron Beam Scattered X-ray Laser Electron beam γ m 0 c 2 (λ 0 [µm] (E 0 [ev]), I [W/cm 2 ] ) φ θ X-ray (λ (E)) LCS X-ray X source Short pulse Energy tunability Quasi- monochromatic Small source size Good directivity Good polarization Compact system etc Many benefits! Scattered X-ray energy E = 1 β cos θ + ( 1 + β cos φ ) 0 ( 1 + cos( θ + φ )) 2 Laser Undulator Radiation X-ray wave length λ0 (1 + K / 2 + γ θ ) λ 2 2γ (1 cosφ) 2 9 K = ea0 / mec λ0 I E 0 E γm c 0 6

7 Laser Compton Scattering (LCS) hard X-ray Source at AIST Application Space Cs-Te 7

8 China-Korea-Japan Joint Workshop on electron/photon sources and applications, Compact UV laser system for rf gun UV laser status We can arbitrary generate a single pulse and multi pulses (100 pulses). All solid-state and compact Pulse energy: 10 µj 100 pulse/ macro pulse Pulse width : 10ps(FWHM) Pulse number: pulses 0.7m Conversion Crystal PC AMP PreAMP Oscillator 1m 1m AOM 8

9 China-Korea-Japan Joint Workshop on electron/photon sources and applications, Cs-Te photocathode rf gun (in Collaborating with KEK and Waseda Univ.) Compact Cs-Te cathode BNL-type RF-gun load-lock system Cathode plug (Mo) Delivering unit New rf gun Electron beam status at rf gun out Energy 4 MeV (40MeV at linac out) Bunch charge 1 nc Bunch length: 3 ps (rms) Bunch number: (Bunch spacing: 12.6 ns ) Repetition rate 10Hz (Max 50Hz) Compact evaporation chamber 9

10 Collision Laser (CPA Ti:Sa laser) for single collision LCS PD 79.3MHz PLL circuit OSC. OC 5W Millennia SESAM(PZT) 79.3 MHz 200 mw Compressor 12480gr/mm 2 Q-ray 10Hz Q-switched Nd: YAG laser 7W~9W 10Hz Q-ray 10Hz Q-switched Nd: YAG laser 4W 50Hz 200 ps 1200gr/mm 2 Regen Ti: SA PBS Stretcher PC AP PBS FR PBS G 50 fs OSC. Pulse pick Hz Pre. AMP. Laser Status Wavelength: 800 nm Pulse energy: mj Pulse width: 100 fs(fwhm) G Main AMP. G 200 mj λ/2 40mJ 60 mj PBS 300mJ 7W (700mJ) Vacuum pipe 10

11 Timing synchronization system (Low-jitter) 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, (2003) Master Oscillator 2856MHz 36th harmonics (2856MHz) 2856MHz Timing stabilizer PD Timing stabilizer fiber ps-laser To rf gun laser 79.3 MHz fs-laser 79.3 MHz To CPA Ti:Sa laser system Drift compensator Drift compensator (Drift <1ps) Klystron To gun & Linacs 2856 MHz Directional Coupler This synchronization system has been accomplished in order to generate 150 fs LCS X-ray in FESTA project in collaborating with SHI. 11

12 Present beam status (single pulse collision single pulse X-ray) Electron beam Electron Energy Energy spread Bunch charge/bunch Bunch length (rms) Beam size (σ x /σ y ) X-ray beam Collision angle (φ) 20 ~ 42 MeV 0.2% 1nC 3ps 40/30 µm Pulse width (rms) TW Ti:Sa Laser beam (CPA) Wave length Energy/pulse Pulse width (FWHM) Beam size (σ x /σ y ) 800 nm 140 mj 100 fs 30 µm Application 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) Max photon energy Number of Photons 90 ~20 kev 150 fs ~10 6 /s ~ 40 kev (tunable) 3 ps ~10 7 /s 12

13 Applications to biological & medical uses 1 Experimental results of in-line phase contrast imaging 2 Experimental results of K-edge imaging 13

14 In-line phase contrast imaging for biological application Sample 1 : lumbar vertebra of rat Sample 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) Experimental Setup 0~750mm 1m H. Ikeura-Sekiguxhi, R. Kuroda et al., APL 92, (2008) K. Yamada, R. Kuroda et al., NIMA (2009)(accepted) In Collaborating with Ibaraki Prefectural University of Health Sciences in Japan 2m IP Sample Be Window (30mmφ) Laser Compton Scattering X-ray Source 14

15 1lumbar vertebra of rat Distance between sample and detector 40mm 750 mm Absorption China-Korea-Japan Joint Workshop on electron/photon sources and applications, Results of in-line phase contrast imaging Phase Contrast 2Hind limbs of normal and OVX mouses Normal Contrast enhancement Comparison 5mm OVX Micro- focus X-ray tube(80kv) LCS X-ray source can realize more contrast enhancement than X-ray tube! We can observe the bone erosion of OVX mouse which is the initial symptom of osteoporosis! 15

16 K-edge imaging for angiography using laser Compton X-ray In Collaborating with Prof. Mori Group at National Cardiovascular Center in Japan in order to research the new diagnosis for the initial symptom of the blood vessel disease (such as diabetes) Samples: Sample1: Resolution chart Sample2: Rabbit ears with iodinated contrast media (K-edge:33.17 kev) Exposure time of 1 frame: 3ps single shot, 30 shot Detector: Real time camera (HARP) with X-ray II K. Yamada, R. Kuroda et al., NIM A 608, pp. S7-S10 (2009) Specimen 2m Detector Be Window (30mmφ) Laser Compton X-ray Source K. Yamada et al., ICFA Workshop "Compton Sources for X/γ Rays: Physics and Applications, Italy, September

17 Real time imaging with picosecond (ps) X-ray pulse Resolution Single shot:250μm 10 shots :125μm Achieved spatial resolution of single shot imaging is 480µm! (System optimization is not completed) Resolution chart Resolution chart Rabbit ear (iodine) 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) 10mm 1 frame/sec 1 frame: 30 ps X-ray (10 shot) 17

18 Multi-Collision Laser Compton Scattering (Multi-LCS) Cavity length:7.6 Laser average energy: 100 mj Laser pulse number : 100 Stored laser power: 10 J Not super cavity Regenerative Amp. type laser cavity! synchronized 100 electron bunches 100 laser pulses 100 X-ray pulses Electron beam is ready 18

19 Calculation of hard X-ray yield using Multi-LCS Parameters for calculation Electron energy 40 MeV Electron charge Bunch number Electron spot size (σ x, σ y ) Electron bunch length Laser wavelength Stored laser power Average laser energy Laser spot size (σ x, σ y ) Laser pulse width Collision angle Maximum LCS X-ray energy LCS photon number Repetition rate Total photon yield 1 nc/bunch µm 10 ps (FWHM) 800 nm 10 J / 100 pulse 100 mj/pulse 38 µm 10 ps (FWHM) 170 deg 38 kev /pulse 10 Hz /s Under development The yield of Multi-LCS hard X-ray on this design was estimated to be about /s. 19

20 Coherent THz radiation source based on S-band compact electron linac 20

21 The high power THz source Design values Electron energy:40 MeV Bunch Charge/bunch :1 nc ~ 2 nc Bunch length : 300 fs ~ 3 ps (1σ) Bunch number:1~100 バンチ Rep. rate:10hz ~ 50Hz Average current: 10μA (2nC Hz) THz freq.: 0.1 ~ 2 THz Pulse energy: >10 nj Peak power: >1 kw THz-Time Domain Spectroscopy THz imaging Ti:Sa fs-laser THz CSR pulse fs electron bunch Achromatic arc. Cs 2 Te photocathode RF gun (Bunch compressor) S-band linac 21

22 Ultra short electron bunch generation S-band compact electron linac Laser photocathode rf gun Achromatic arc section S-band linac 8m Energy Achromatic arc section E>E 0 time E<E 0 Energy distribution E<E 0 E=E 0 E>E 0 Bunch compression using achromatic arc 22

23 Generation of THz coherent synchrotron radiation (CSR) Bunch length monitor W-band detector (WiseWave FAS-10SF-01) Generation of ultra-short electron bunch & THz CSR Coherent radiation Frequency range: around 0.1THz 0.075~0.11THz (2.7~4.0mm) Aperture :1mm(H) X 2mm(V) Sensitivity:500mV / 1mW 23

24 THz scanning transmission imaging Coherent THz pulse WR-10 wave guide Detector antenna Wave guide Parabolic antenna XY Stage Sample position Japanese Train card sample XY THz detector (0.1,

25 liquid bond bonded by removing water high polymer Optical image THz image after 1 week Polypropylene plate 2mm 2mm 25

26 China-Korea-Japan Joint Workshop on electron/photon sources and applications, Other Imaging results Sample 1 Vegetable Sample 2 Biological imaging (pork) 5 cm C.S/JR東日本/D fat 3 cm Protein 0 hour Sample3 Inside of Envelope Envelope 10 hours later Sample 4 Credit Card 9cm 14 hours Credit card with IC chip 26

27 THz-TDS system design China-Korea-Japan Joint Workshop on electron/photon sources and applications, Under development! PD Off-axis parabolic mirror Polarizer PD THz-pulse 0.1~2 THz, 700fs Sample EO crystal (ZnTe) 1/4λplate Quartz window (z-cut single crystal) Ti:Sa laser 800nm, 50fs Polarizer Fourier transform Optical delay stage Time domain (THz temporal distribution) Freq. domain (Spectrum distribution) 27

28 Summary Laser Compton scattering X-ray source based on S-band linac X-ray energy : 12-40keV (electron beam energy: 42MeV) Photon number : > Hz application to medical and biological imaging was started. In near future, we will generate more than 10 9 /s via Multi-LCS for biological and medical applications. Coherent THz radiation source based on S-band linac The coherent THz radiation has been observed on S-band compact electron linac at AIST. THz scanning transmission imaging has been successfully demonstrated for many samples. In near future, we will finish set up of the high power THz-TDS system and start the investigation of the un-researched materials in the frequency range of THz. Thank you for your attention! 28