Parametric Xray radiation PXR generator composed of an

Parametric X-ray radiation (PXR) generator composed of an electron linac and a double-crystal system Y. Hayakawa, I. Sato, K. Hayakawa, T. Tanaka Institute of Quantum Science, Nihon University LEBRA

Facility (LEBRA) Laboratory for Electron Beam Research and Application Nihon University S-band electron linac Max. energy 125 Me. V Beam intensity Duration 100 m. A 20 ms Repetition 12. 5 Hz Average current Emittance 25 m. A 15 p mm mrad LEBRA

Background of the project Nihon University LEBRA Users • Biology • Medical Science • Dentistry • Material Science X-ray source • Advanced electron linac • Free electron laser (FEL) Visible to near-IR Collaboration High Energy Accelerator Research Organization (KEK) Parametric X-ray Radiation (PXR) LEBRA

History of LEBRA 1994 : The FEL project was started. 1995 : The construction of the linac was started. 1997 : Completion of the linac & the undulator 1998 : Success in acceleration of electron beams 2000 : Design of the PXR generator was started. 2001 : The PXR generator was constructed. First lasing of FEL 2003 : Operation of the PXR generator will be started. LEBRA

Why PXR ? • Variable wavelength X-ray source • Monochromaticity • Directivity • Electron energy limitation ~ 100 Me. V undulator / wiggler • Beam destruction : no problem LEBRA

Weak points of PXR as X-ray source • Emission direction changes as the wavelength varies. Double-crystal system • X-ray yield is not intense. X-ray focusing system LEBRA

Concept of the PXR generator (+, -) parallel arrangement LEBRA

Detuning of reflection crystal f = 8. 415685 deg. f = 8. 418685 deg. LEBRA

Dependence on Bragg angle LEBRA

Cross section and energy gradation LEBRA

Polarization of X-ray beam horizontal component vertical component LEBRA

Advantages of the double-crystal system • X-ray exit is fixed for all wavelengths Important for application studies • X-ray source point is almost fixed Focusing is easy • Reduction of g-ray influx • Filtering effect for higher harmonics LEBRA

Beam lines of LEBRA linac 100 Me. V electron linac PXR beam line FEL beam line X-ray exit LEBRA

Inside of the PXR generator 2 nd gonio e-beam 1 st gonio permanent Q-magnet LEBRA

Side view LEBRA

Specification of the PXR generator spec of goniometers axis range resolution qz (rotation) qx (swivel) qy (swivel) 0 ~ +35 deg. 11. 6 mrad -10 ~ +10 deg. 52. 4 mrad -10 ~ +10 deg. 35 mrad Y (parallel) -10 ~ +1030 mm 5 mm energy range of X-rays Si (111) Si (220) 3. 95 ~ 22. 6 ke. V 6. 46 ~ 37. 0 ke. V LEBRA

Photograph of the PXR beam line LEBRA

Focusing by grazing optics (ellipsoid mirror) 12. 0 m for horizontal for vertical LEBRA

Rhodium coated ellipse mirrors Rh : Z = 45 A = 102. 9 r = 12. 44 g/cm 3 LEBRA

Focusing mirror controller vacuum chamber goniometer LEBRA

Focusing effect 1. 7 x 10 -10 photons/e- mm 2 at X-ray window ( 7 m away ) 5. 7 x 10 -11 photons/e- mm 2 ( 12 m away ) target: Si(111) (0. 1 mm thick ) energy: 13. 5 ke. V X-ray beam profile at 12 m from the source point LEBRA

Focusing effect 1. 5 x 10 -10 photons/e- (6 mm)2 = 4. 4 x 10 -6 photons/e- mm 2 at the focus point ( 12 m away ) brilliance: 104 ~ 105 increase ! macropulse (100 m. A, 20 ms) 5. 5 x 107 photons/mm 2 = 2. 7 x 1012 photons/sec mm 2 ( 1. 9 x 103 photons ) X-ray beam profile at 12 m from the source point LEBRA

Energy spread at the focus point LEBRA

Brilliance of X-rays Brilliance of PXR 3 rd generation SR During macropulse 2 nd generation SR Average Rotor X-ray tube Year LEBRA

Summary • Double-crystal PXR generator based on the 100 Me. V electron linac has been designed and constructed. • The fixed-exit and the fixed source point is useful for the application studies. • Numerical estimation indicates the X-ray focusing system leads the PXR generator to a high performance pulsed X-ray source almost equal to 2 nd generation SR. sufficient as a facility of a single university LEBRA

To. Do • Commissioning of the new beam line for PXR • Achievement of the first light • Demonstration of the focusing effect for application studies • Development of • Imaging device for pulsed X-rays X-ray CCD, Microstrip gas chamber, … • Advanced X-ray optics LEBRA

End LEBRA

Appendix LEBRA

Formula of PXR yield g: reciprocal lattice vector of the crystal v: electron velocity W: direction of photon emission L: crystal thickness w: angular frequency of photon LEBRA

Beam line for PXR generator LEBRA

Characteristics of LEBRA Linac Maximum energy : Frequency : pulse duration : repetition rate : klystron : 125 Me. V 2856 MHz 20 ms 12. 5 Hz 30 MW x 2 electron gun : SHB : thermal cathode, DC – 100 k. V no prebuncher : 7 -cell traveling wave type LEBRA

125 Me. V S-band electron Linac LEBRA

injector LEBRA

prebuncher LEBRA

phase LEBRA

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Filtering effect for higher harmonics LEBRA

Filtering effect for higher harmonics LEBRA

Focusing effect 3. 5 x 10 -10 photons/eat X-ray window ( 7 m away ) 1. 2 x 10 -10 photons/e( 12 m away ) target: Si(111) (0. 1 mm thick ) energy: 5. 4 ke. V X-ray beam profile at 12 m from the source point LEBRA

Focusing effect 3. 2 x 10 -10 photons/e- 200 mm 2 = 1. 6 x 10 -6 photons/e- mm 2 at the focus point ( 12 m away ) brilliance: 103 ~ 104 increase ! macropulse (100 m. A, 20 ms) 2. 0 x 107 photons/mm 2 = 1. 0 x 1012 photons/sec mm 2 ( 4. 0 x 103 photons ) X-ray beam profile at 12 m from the source point LEBRA

Hatch station for application studies LEBRA

Energy spread at the focus point LEBRA

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