Author: Zen, H.
Paper Title Page
TUPA02 Development of Material Analysis Facility in KU-FEL 190
 
  • K. Yoshida, M. A. Bakr, Y.W. Choi, H. Imon, K. Ishida, T. Kii, N. Kimura, R. Kinjo, K. Komai, K. Masuda, H. Ohgaki, M. Omer, S. Shibata, K. Shimahashi, T. Sonobe, H. Zen
    Kyoto University, Institute for Advanced Energy, Kyoto, Japan
  
  A mid in­frared-free elec­tron laser (MIR-FEL) (5-20 μm) fa­cil­ity (KU-FEL: Kyoto Uni­ver­sity Free Elec­tron Laser) has been con­structed for con­tribut­ing to re­searches on en­ergy sci­ence at In­sti­tute of Ad­vanced En­ergy, Kyoto Uni­ver­sity. Up to now 12-14 μm FEL beam has been gen­er­ated. When MIR-FEL with the wave­length matched to the mol­e­c­u­lar vi­bra­tion mode is ir­ra­di­ated to the ma­te­r­ial, a par­tic­u­lar chem­i­cal bond in the ma­te­r­ial will be se­lec­tively ex­cited, or dis­so­ci­ated [1]. The se­lec­tive pho­to­chem­i­cal re­ac­tion can be ap­plied for sur­face mod­i­fi­ca­tion and the eval­u­a­tion of ma­te­r­ial in bio­chem­istry, chem­istry, and solid physics. There­fore, ma­te­r­ial analy­sis fa­cil­ity in com­bi­na­tion with MIR-FEL is con­structed. In the ma­te­r­ial analy­sis fa­cil­ity, ad­vanced analy­sis sys­tems such as pho­to­lu­mi­nes­cence mea­sure­ment sys­tem, pho­to­elec­tron spec­troscopy, super cen­trifuge and high per­for­mance liq­uids chro­matog­ra­phy, ICP emis­sion spec­troscopy, and high speed atomic force spec­troscopy are in­stalled. In this meet­ing, the de­vel­op­ment of ma­te­r­ial analy­sis fa­cil­ity will be in­tro­duced.
[1] Jhon C.Tully, Science, 312(2006) 1004 		 
 
WEPB17 Evaluation of Lasing Range with a 1.8 m Undulator in KU-FEL 417
 
  • K. Ishida, M. A. Bakr, Y.W. Choi, H. Imon, T. Kii, N. Kimura, R. Kinjo, K. Komai, K. Masuda, H. Ohgaki, M. Omer, S. Shibata, K. Shimahashi, T. Sonobe, K. Yoshida, H. Zen
    Kyoto University, Institute for Advanced Energy, Kyoto, Japan
  
  In KU-FEL (Kyoto Uni­ver­sity FEL) 12-14 μm FEL has been avail­able by using a 40 MeV S-bend linac and 1.6 m un­du­la­tor. We are going to in­stall 1.8 m un­du­la­tor which was used in JAEA to ex­tend the las­ing range of KU-FEL. Nu­mer­i­cal eval­u­a­tion of the las­ing range has been car­ried out by using GEN­E­SIS1.3. How­ever, this work used an ideal un­du­la­tor field data which was mea­sured by JAEA in sev­eral years be­fore. There­fore we re-mea­sured the un­du­la­tor field for dif­fer­ent gaps. Then we eval­u­ated the FEL gain and pos­si­ble las­ing range with 1.8 m un­du­la­tor using mea­sured un­du­la­tor field. The un­du­la­tor field mea­sure­ment, FEL gain cal­cu­la­tions and eval­u­a­tion of las­ing range in KU-FEL will be pre­sented in the con­fer­ence.  
 
WEPB19 Enhancement of Undulator Field in Bulk HTSC Staggered Array Undulator with Hybrid Configuration 424
 
  • R. Kinjo, M. A. Bakr, Y.W. Choi, H. Imon, K. Ishida, T. Kii, N. Kimura, K. Komai, K. Masuda, K. Nagasaki, H. Ohgaki, M. Omer, S. Shibata, K. Shimahashi, T. Sonobe, K. Yoshida, H. Zen
    Kyoto University, Institute for Advanced Energy, Kyoto, Japan
  
  Funding: This work was supported by the Grant-in-Aid for Scientific Research B and JSPS Fellows by the Ministry of Education, Culture, Sports, Science and Technology of Japan
The pur­pose of this study is en­hance­ment of the un­du­la­tor field and it's sta­bil­ity in bulk high tem­per­a­ture su­per­con­duc­tor stag­gered array un­du­la­tor by in­tro­duc­ing hy­brid con­fig­u­ra­tion. The au­thors made the mag­netic field cal­cu­la­tions with some hy­brid con­fig­u­ra­tions con­sists of bulk HTSCs, fer­ro­mag­netic pieces and per­ma­nent mag­nets. We also made pro­to­type mea­sure­ments. The re­sults shows the hy­brid con­fig­u­ra­tion can gen­er­ates stronger and more uni­form mag­netic field than bulk-HTSCs-only con­fig­u­ra­tion. In this con­fer­ence, nu­mer­i­cal and ex­per­i­men­tal re­sults of the hy­brid con­fig­u­ra­tion will be pre­sented. 		 
 
THPA34 Assessment of Thermionic Emission Properties and Back Bombardment Effects for LaB6 and CeB6 557
 
  • M. A. Bakr, Y.W. Choi, H. Imon, K. Ishida, T. Kii, N. Kimura, R. Kinjo, K. Komai, K. Masuda, H. Ohgaki, M. Omer, S. Shibata, K. Shimahashi, T. Sonobe, K. Yoshida, H. Zen
    Kyoto University, Institute for Advanced Energy, Kyoto, Japan
  • M. Kawai
    Tohoku University, School of Science, Sendai, Japan
  
  Back Bom­bard­ment (BB) ef­fect lim­its wide usage of thermionic RF guns. BB ef­fect in­duces not only ramp­ing-up of a cath­ode’s tem­per­a­ture and beam cur­rent, but also degra­da­tion of cav­ity volt­age and beam en­ergy dur­ing the macropulse. In this re­search we are clar­i­fy­ing BB phe­nom­e­non and find out cath­ode ma­te­r­ial prop­er­ties con­tri­bu­tion on BB ef­fect. There­fore, as­sess­ment of emis­sion prop­er­ties and com­par­i­son of BB ef­fect in LaB6 and CeB6 are in­tro­duced. Emis­sion prop­er­ties for these ma­te­ri­als are mea­sured in tem­per­a­ture range be­tween 1600 and 2100 K. Then, heat­ing prop­erty of ma­te­ri­als is in­ves­ti­gated against BB ef­fect by nu­mer­i­cal cal­cu­la­tion of stop­ping range and de­posited heat. Fi­nally, change in cath­ode tem­per­ate and cor­re­spond­ing change in cur­rent den­sity dur­ing 6 μs pulse du­ra­tion is de­ter­mined. Ex­per­i­men­tal re­sults es­ti­mates work func­tions at 1800 K for LaB6 and CeB6 were 2.8 and 2.75 eV re­spec­tively. Our sim­u­la­tion of BB ef­fect shows that for a pulse of 6 μs du­ra­tion, LaB6 cath­ode ex­pe­ri­ences a large change in tem­per­a­ture com­pared with CeB6. The change in cur­rent den­sity is two times higher. The ex­per­i­men­tal and sim­u­la­tion re­sults will be pre­sented in the meet­ing  
 
TUPA11 Saturation Effect on VUV Coherent Harmonic Generation at UVSOR-II 212
 
  • T. Tanikawa
    PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
  • M. Adachi, M. Katoh, J. Yamazaki, H. Zen
    UVSOR, Okazaki, Japan
  • M. Hosaka, Y. Taira, N. Yamamoto
    Nagoya University, Nagoya, Japan
  
  Light source by using a laser seed­ing tech­nique are under de­vel­op­ment at the UVSOR-II elec­tron stor­age ring. In the past ex­per­i­ments, we have suc­ceeded in gen­er­at­ing co­her­ent har­mon­ics (CHs) in deep ul­tra­vi­o­let (UV) and vac­uum UV (VUV) re­gion, and also in gen­er­at­ing CH with vari­able po­lar­iza­tions in deep UV [1]. In pre­vi­ous con­fer­ences, we re­ported an in­tro­duc­tion of new-con­structed spec­trom­e­ter for VUV and re­sults of spec­tra mea­sure­ment, un­du­la­tor gap de­pen­den­cies, and in­jec­tion laser power de­pen­den­cies on VUV CHs [2]. This time we have suc­cess­fully ob­served sat­u­ra­tion on CHs in­ten­si­ties and have found some in­ter­est­ing phe­nom­ena, which are the nec­es­sary power of in­jec­tion laser to achieve the sat­u­ra­tion of CHG is dif­fer­ent in dif­fer­ent har­monic or­ders, and the CH in­ten­sity is os­cil­lated in deep sat­u­rated regime. In this con­fer­ence, we will dis­cuss the re­sults of some sys­tem­atic mea­sure­ments and those an­a­lyt­i­cal and par­ti­cle track­ing sim­u­la­tions.
[1] M. Labat, et al., Phys. Rev. Lett. 101 (2008) 164803
[2] T. Tanikawa, et al., Prc. 1st Int. Particle Accelerator Conf., Kyoto, 2010.
[3] T. Tanikawa, et al., Appl. Phys. Express 3 (2010) 122702 		 
 
TUPA13 Present Status and Future Prospects of Project on Utilizing Coherent Light Sources for User Experiments at UVSOR-II 215
 
  • H. Zen, K. Hayashi, S.I. Kimura, E. Nakamura, J. Yamazaki
    UVSOR, Okazaki, Japan
  • M. Adachi, M. Katoh
    Sokendai - Okazaki, Okazaki, Aichi, Japan
  • M. Hosaka, Y. Takashima, N. Yamamoto
    Nagoya University, Nagoya, Japan
  • T. Takahashi
    Kyoto University, Research Reactor Institute, Osaka, Japan
  
  Funding: Quantum Beam Technology Program supported by JST/MEXT (Japan)
We have been in­ten­sively de­vel­op­ing co­her­ent light sources uti­liz­ing elec­tron bunches in the stor­age ring, UVSOR-II, by adding some ex­ter­nal com­po­nents to the ring. After suc­cess­ful gen­er­a­tion of co­her­ent syn­chro­tron ra­di­a­tion (CSR) in THz range* and co­her­ent har­monic gen­er­a­tion (CHG) in DUV range** by using an in­tense dri­ving laser, a 5-year new re­search pro­ject named as Quan­tum Beam Tech­nol­ogy Pro­gram has been started from FY2008. The pro­ject in­cludes in­tro­duc­tion of new dri­ving laser sys­tem, ded­i­cated un­du­la­tors and beam­lines, and aims at uti­liz­ing those co­her­ent ra­di­a­tions for user ex­per­i­ments. The new dri­ving laser sys­tem has been in­stalled last year. The un­du­la­tors and beam­lines are now under con­struc­tion. In­stal­la­tion of those com­po­nents will be fin­ished be­fore the con­fer­ence. In the con­fer­ence, we will re­port on the pre­sent sta­tus of sys­tem de­vel­op­ment and fu­ture plan of ap­pli­ca­tion ex­per­i­ments.
*M. Shimada et al., Japanese Journal of Applied Physics, vol. 46, pp. 7939-7944 (2007).
**M. Labat et al., European Physical Journal D, vol. 44, pp. 187-200 (2007). 		 
 
WEPA17 Technical Developments for Injecting External Laser to a Storage Ring FEL in CW and Q-switched Operation 362
 
  • H. Zen
    UVSOR, Okazaki, Japan
  • M. Adachi, M. Katoh
    Sokendai - Okazaki, Okazaki, Aichi, Japan
  • S. Bielawski, C. Szwaj
    PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
  • M. Hosaka
    Nagoya University, Nagoya, Japan
  
  For con­trol­ling the dy­nam­ics of a stor­age ring FEL, we pro­pose to in­ject the FEL os­cil­la­tor with an ex­ter­nal laser [1]. An­other pur­pose is gen­er­a­tion of long sus­tain and in­tense co­her­ent syn­chro­tron ra­di­a­tion with com­bin­ing Q-switched and in­jected FEL [2]. In this pre­sen­ta­tion, we will re­port on tech­ni­cal de­vel­op­ments for in­ject­ing the ex­ter­nal laser to FEL os­cil­la­tor, which works both in CW and Q-switched op­er­a­tion. Op­ti­cal sys­tem for in­ject­ing ex­ter­nal laser and RF mod­u­la­tion sys­tem for Q-switch­ing are newly de­vel­oped. Prac­ti­cal prob­lems and way to over­come them will be dis­cussed.
[1] C. Szwaj et al., FEL2011, TUPB05, in this conference.
[2] M. Hosaka et al., FEL2011, WEOC4, in this conference. 		 
 
WEPA18 Chirped Pulse Generation by CHG-FEL 366
 
  • H. Zen, T. Tanikawa
    UVSOR, Okazaki, Japan
  • M. Adachi, M. Katoh
    Sokendai - Okazaki, Okazaki, Aichi, Japan
  • M. Hosaka, N. Yamamoto
    Nagoya University, Nagoya, Japan
  
  Funding: Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Young Scientists (B), 23760067 (Japan)
Co­her­ent Har­monic Gen­er­a­tion Free Elec­tron Laser (CHG-FEL)* is one of the promis­ing ways to gen­er­ate co­her­ent, fem­tosec­ond and short-wave­length op­ti­cal pulses from elec­tron bunches cir­cu­lat­ing in an elec­tron stor­age ring. How­ever, the CHG pulse en­ergy be­comes smaller as the shorter pulse of laser is used for dri­ving CHG-FEL be­cause the num­ber of elec­trons which con­tribute to the CHG pro­duc­tion is lim­ited by the pulse du­ra­tion of dri­ving laser. We pro­posed “chirped pulse gen­er­a­tion and com­pres­sion of CHG-FEL” to over­come such trade-off re­la­tion­ship, and got a small bud­get for proof-of-prin­ci­ple ex­per­i­ments in DUV re­gion. In the ex­per­i­ment, chirped DUV pulses will be gen­er­ated by CHG-FEL dri­ving with chirped laser, and the DUV pulses will be com­pressed by a pulse com­pres­sor. The pulse du­ra­tion of CHG-FEL be­fore and after the com­pres­sor will be mea­sured by a cross­cor­re­la­tor. The prin­ci­ple, strat­egy, pre­sent sta­tus, and fu­ture prospects will be pre­sented in the con­fer­ence.
*R. Coisson and F De Martini, Physics of Quantum Electronics (Addison−Wesley, 1982) vol. 9. chap. 42. 		 
 
WEOC4
 Intense Coherent THz Synchrotron Radiation Induced by a Storage Ring FEL Seeded with a Femtosecond Laser  
 
  • M. Hosaka, Y. Taira, Y. Takashima, N. Yamamoto
    Nagoya University, Nagoya, Japan
  • M. Adachi, M. Katoh, T. Tanikawa, H. Zen
    UVSOR, Okazaki, Japan
  • S. Bielawski, C. Szwaj
    PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
  • C. Evain
    SOLEIL, Gif-sur-Yvette, France
  
  Very re­cently, we have suc­ceeded in seed­ing a res­onator FEL by in­ject­ing an ex­ter­nal fem­tosec­ond laser at the UVSOR-II stor­age ring [1]. In­tense co­her­ent syn­chro­tron ra­di­a­tion (CSR) in the THz re­gion from a bend­ing mag­net was ob­served when the seeded FEL was op­er­ated in the pulsed Q-switch mode [2]. We have also found that the CSR in­ten­sity de­pends on the pulse du­ra­tion of the seed laser. The CSR in­ten­sity is en­hanced with short pulse ~200 fsec and sup­pressed with longer pulse ~200 psec. Si­mul­ta­ne­ous mea­sure­ment of the ter­a­hertz ra­di­a­tion and the FEL pulse re­veals that the ra­di­a­tion is emit­ted in the grow­ing phase of the Q-switch FEL pulse. We think that the CSR comes from repet­i­tive in­ter­ac­tions be­tween the laser pulse and the elec­tron bunch as the short pulse laser growth in the op­ti­cal cav­ity. In the pre­sen­ta­tion, we will also dis­cuss the pro­duc­tion mech­a­nism of the CSR.
[1] C. Szwaj et al., FEL2011, TUPB05, in this conference.
[2] H. Zen et al., FEL2011, TUPA13, in this conference.
 		 
slides icon Slides WEOC4 [2.715 MB]