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FJPPL optical cavity Compton collaboration Optical Stacking Cavity for ILC Compton e + source. Junji Urakawa (KEK). FJPPL2008 @KEK 15/May/2008. Today's Talk. 1. Introduction. 2. Goal of the R&D. 3. R/D status in Japan. 4. Future R&D. 5. World-wide collaboration. 6. Summary.
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FJPPL optical cavity Compton collaboration Optical Stacking Cavity for ILC Compton e+ source Junji Urakawa (KEK) FJPPL2008@KEK 15/May/2008
Today's Talk 1. Introduction 2. Goal of the R&D 3. R/D status in Japan 4. Future R&D 5. World-wide collaboration 6. Summary
Two ways to get pol. e+ (1) Helical Undurator e- beam E >150 GeV Undulator L > 200 m Our Proposal (2) Laser Compton
325 MHz 325 MHz Laser Pulse Stacking Cavity Reuse high power laser pulse by optical cavity. Laser-electron small crossing angle Laser bunches Lcav = n /2 Lcav = m Llaser n, m : integer Cavity Enhancement Factor = 1000 - 105
Goal of our R&D a) 1.7x1012 photons x 2700 bunches/train /20% bandwidth during 100msec b) The efficiency of whole system highly depends on the optical cavity design. laser spot size is less than 10mm. collision angle is less than 8 degree. enhancement factor is more than 100000. c) 220mJ @1064nm in the cavity, 5 cavities d) 2.2mJ @325MHz ---1kW laser oscillator e) Fiber Amplifiers Assuming 2nC/bunch, 1psec bunch length of electron bunch and 1psec laser pulse width, 325MHz collision frequency.
R/D Status in Japan Moderate Enhancement ~ 1000 Moderate spot size ~ 30 micron Simple cavity stucture with two mirrors Get experinence with 43MeVand 1.3GeVe- beam Laser Undulator Compact X-ray (LUCX)Project at KEK-ATF 43MeV Multi-bunch beam+ Super-Cavity = 33keV X-ray. Expected X-ray is generated.
43MeV Multi-bunch beam+ Super-Cavity = 33keV X-ray. Multi-bunch photo-cathode RF Gun Laser Undulator Compact X-ray (LUCX)Project at KEK-ATF (Kyoto-Waseda-KEK) X-ray Detector S-band Acc. Structure Beam size at CP 60mm in s Multi-bunch e- beam 300nC at gun At present, laser waist size is 30mm in s. We should reduce both beam size at CP down to 30mm. 33keV X-ray generation based on inverse Compton scattering is started from May 2007 with Super-Cavity. Storage Laser power 36kW, 7psec(FWHM), next step :1MW
-ray Generation with Laser Pulse Stacking Cavity(Hiroshima-Waseda-IHEP-KEK) 1.Achieve high enhancement & small spot size 2.Establish feedback technology 3.Achieve small crossing angle 4.Get experinence with e- beam We should detect 20 g’s/collision. e-beam laser beam pulse stacking cavity in vacuum chamber
Application 1. ~Compact X-ray Sources~ Compact X-ray source is required from various fields. >Medical Diagnosis Angiography, Mammography … >Biological Sciences Soft X-ray microscopy … >Drag Manufacturing X-ray protein crystal structure analysis … Our aim~Medical Application~ Development of compact high brightness X-ray generator for K-edge digital subtraction angiography. Angiography is a procedure that enables blood vessels to be visualized using the absorption by Iodine at 33keV 2. High brightness g-ray beam Nondestructive assay of radio-nuclides in nuclear waste by nuclear resonance fluorescence : 1010 photons/sec・keV for Interrogation of fissile material in cargoes and versatile method of nondestructive analysis of both radioactive and stable nuclides.
Future R/D Achieve both high enhancement(1000) & small spot (30mm) (less stabile) & (less stabile) 1. Points for high enhancement factor remove/suppress vibration establish feed-back technology (Mirror R = 99.7%-R=99.9%-R=99.99%-R=99.999%?) Next step : from 1000 to 10000 or 100000 2. Points for small spot 2 - Lcav --> +0 Next step : from 30mm to 10mm or 6mm good matching between laser and cavity
10W, 357MHz 8000 6000 Counts/crossing 4000 2000 0 0 10 20 30 crossing angle 3. Points of R/D (continued) Achieve smaller crossing angle Number of -rays strongly depends on crossing angle ATF e- bunch length = 9 mm (rms) Ne = 1x1010/bunch (In the case of 1mm bunch length, this dependence is not strong.) Short bunch beam is preferable. Next step : from 12 degree to 8 degree or 5 degree. --> Small crossing angle is preferable. --> constraint in chamber design
L R Laser stacking cavity with Two Spherical Mirrors Choice of R and spot size L = 420.00 mm our choice for 1st prototype concentric configuration R + R ~ L
World-Wide-Web of Laser Compton 4th Generation light source ERL CLIC e+ ILC e+ Laser Compton Polari- metry gg collider NuclearAssay Diagnostic Optical Cavity X-ray source LW monitor Medical applications High power laser e- source ILC, ERL Industrial applications
Summary 1. Compton e+ source is an advanced alternative of ILC e+ source 2. Laser stacking cavity is a key. 3. In Japan, we are generating X-ray and -ray by installing the stacking cavity in LUCX and ATF-DR. 4. In France, we are developing a very advanced cavity with 4 mirrors. In 2009, a 4 mirror cavity will be installed in ATF-DR for -ray generation.-next talk. 5. We have world-wide collaboration for Compton. Not only for ILC e+ source. Also for many other applications.
Expected Number of g-rays at ATF Number of g-rays/bunch Electron :Ne = 2x1010 (single bunch operation) Laser : 10 W (28 nJ/bunch) Optical Cavity: Enhancement = 1000 Ng =2500/bunch X-ing angle = 5 deg Ng =1300/bunch X-ing angle = 10 deg Ng = 900/bunch X-ing angle = 15 deg Number of g-rays/second Electron :Ne =2x1010 (multi-bunch and multi-train operation) Electron 20 bunches/train, 3 trains/ring Laser : 10 W (28 nJ/bunch) Optical Cavity: Enhancement = 1000 Ng = 3.4x1011/sec X-ing angle = 5 deg Ng = 1.7x1011/sec X-ing angle = 10 deg Ng = 1.1x1011/sec X-ing angle = 15 deg
Cavity History in Japan by H. Sato (Posipol 2006)
World-wide Collaboration PosiPol Collaboration Collaborating Institutes: BINP, CERN, DESY, Hiroshima, IHEP, IPN, KEK, Kyoto, LAL, NIRS, NSC-KIPT, SHI, Waseda, BNL, and ANL Sakae Araki, Yasuo Higashi, Yousuke Honda, Masao Kuriki, Toshiyuki Okugi, Tsunehiko Omori, Takashi Taniguchi, Nobuhiro Terunuma, Junji Urakawa, X. Artru, M. Chevallier, V. Strakhovenko, Eugene Bulyak, Peter Gladkikh, Klaus Meonig, Robert Chehab, Alessandro Variola, Fabian Zomer, Alessandro Vivoli, Richard Cizeron, Frank Zimmermann, Kazuyuki Sakaue, Tachishige Hirose, Masakazu Washio, Noboru Sasao, Hirokazu Yokoyama, Masafumi Fukuda, Koichiro Hirano, Mikio Takano, Tohru Takahashi, Hirotaka Shimizu, Shuhei Miyoshi, Akira Tsunemi, Li XaioPing, Pei Guoxi,Jie Gao, V. Yakinenko, Igo Pogorelsky, Wai Gai, and Wanming Liu POSIPOL 2007 LAL-Orsay, France 23-25 May POSIPOL 2006 CERN April 2006 http://events.lal.in2p3.fr/conferences/Posipol07/ http://posipol2006.web.cern.ch/Posipol2006/