• A. Sagisaka, P.R. Bolton, S.V. Bulanov, H. Daido, T. Esirkepov, T. Hori, S. Kanazawa, H. Kiriyama, K. Kondo, S. Kondo, M. Mori, Y. Nakai, M. Nishiuchi, K. Ogura, H. Okada, S. Orimo, A.S. Pirozhkov, H. Sakaki, F. Sasao, H. Sasao, T. Shimomura, A. Sugiyama, H. Sugiyama, M. Tampo, M. Tanoue, D. Wakai, A. Yogo
  JAEA, Kyoto
• I.W. Choi, J. Lee
  APRI-GIST, Gwangju
• H. Nagatomo
  ILE Osaka, Suita
• K. Nemoto, Y. Oishi
  Central Research Institute of Electric Power Industry, Yokosuka-shi, Kanagawa

High-in­ten­si­ty laser and thin-foil in­ter­ac­tions pro­duce high-en­er­gy par­ti­cles, hard x-ray, high-or­der har­mon­ics, and ter­a­hertz ra­di­a­tion. A pro­ton beam driv­en by a high-in­ten­si­ty laser has re­ceived at­ten­tion as a com­pact ion source for med­i­cal ap­pli­ca­tions. We have per­formed the high in­ten­si­ty laser-mat­ter in­ter­ac­tion ex­per­i­ments using a thin-foil tar­get ir­ra­di­at­ed by Ti:sap­phire laser (J-KAREN) at JAEA. In this laser sys­tem, the pulse du­ra­tion is 40 fs (FWHM). The laser beam is fo­cused by an off-ax­is parabol­ic mir­ror at the tar­get. The es­ti­mat­ed peak in­ten­si­ty is ~5x10¹⁹ W/cm². We have de­vel­oped on-line real time mon­i­tors such as a time-of-flight pro­ton spec­trom­e­ter which is placed be­hind the tar­get and in­ter­fer­om­e­ter for elec­tron den­si­ty pro­file mea­sure­ment of pre­formed plas­ma. We ob­served the max­i­mum pro­ton en­er­gy of ~7 MeV.

• S. Kashiwagi, K. Furuhashi, G. Isoyama, R. Kato, M. Morio, N. Sugimoto, Y. Terasawa
  ISIR, Osaka
• H. Hayano, H. Sugiyama, T. Takatomi, J. Urakawa
  KEK, Ibaraki
• H. Iijima, M. Kuriki
  HU/AdSM, Higashi-Hiroshima

We con­duct re­search on Free Elec­tron Laser (FEL) in the in­frared re­gion and pulse ra­di­ol­y­sis for ra­di­a­tion chem­istry using the 40 MeV, 1.3 GHz L-band linac of Osaka Uni­ver­si­ty. At pre­sent, the L-band linac is equipped with a thermion­ic elec­tron gun. It can ac­cel­er­ate a high-in­ten­si­ty sin­gle-bunch beam with charge up to 91 nC but the nor­mal­ized emit­tance is large. In order to ad­vance the re­search, we have begun de­vel­op­ment of a pho­to­cath­ode RF gun for the L-band elec­tron linac in col­lab­o­ra­tion with KEK and Hi­roshi­ma Uni­ver­si­ty. We start the basic de­sign of the RF gun cav­i­ty for the L-band linac at ISIR, Osaka Uni­ver­si­ty, based on the 1.5 cells, which is a nor­mal con­duct­ing pho­to­cath­ode RF gun. A ma­te­ri­al of the cath­ode should be Cs2Te, which has the high quan­tum ef­fi­cien­cy of a few per­cents, to pro­duce a beam with high charge up to 30 nC/bunch. We im­prove the cool­ing sys­tem of the cav­i­ty for high duty op­er­a­tion to sup­press the ther­mal de­for­ma­tion due to the heat load of input rf power. The sim­u­la­tion study has been also per­formed for the L-band linac at ISIR with a high charge elec­tron beam. In this con­fer­ence, we de­scribe the de­tails of the L-band pho­to­cath­ode RF gun de­vel­op­ment.

• M. Kuriki, H. Iijima
  HU/AdSM, Higashi-Hiroshima
• H. Hayano, Y. Honda, H. Sugiyama, J. Urakawa
  KEK, Ibaraki
• G. Isoyama, S. Kashiwagi, R. Kato
  ISIR, Osaka
• E. Katin, E. Khazanov, V. Lozhkarev, G. Luchinin, A. Poteomkin
  IAP/RAS, Nizhny Novgorod
• G. Shirkov, G.V. Trubnikov
  JINR, Dubna, Moscow Region

Aim of Su­per-con­duct­ing Test Fa­cil­i­ty (STF) at KEK is demon­strat­ing tech­nolo­gies for In­ter­na­tion­al Lin­ear Col­lid­er. In STF, one full RF unit will be de­vel­oped and beam ac­cel­er­a­tion test will be made. In su­per-con­duct­ing ac­cel­er­a­tor, pre­cise RF con­trol in phase and power is es­sen­tial be­cause the input RF power should be bal­anced to beam ac­cel­er­at­ing power. To demon­strate the sys­tem fea­si­bil­i­ty, the beam ac­cel­er­at­ing test is an im­por­tant step in R&D phase of STF and ILC. To pro­vide ILC for­mat beam for STF, we de­vel­op an elec­tron source based on pho­to-cath­ode L-band RF gun. To gen­er­ate ILC for­mat beam, we de­vel­oped a laser sys­tem based on Yb fiber os­cil­la­tor in 40.6 MHz. The pulse rep­e­ti­tion is de­creased by pick­ing puls­es in 2.7 MHz, which meets ILC bunch spac­ing, 364 ns. The pulse is then am­pli­fied by YLF laser up to 8 uJ per pulse in 1 mm. The light is con­vert­ed to 266 nm by SHG and FHG. Fi­nal­ly, 1.5 uJ per pulse is ob­tained and 3.2 nC bunch charge will be made. We re­port the basic per­for­mance of the laser sys­tem from the ac­cel­er­a­tor tech­nol­o­gy point of a view.