• K. Yamada, T. Dantsuka, M. Fujimaki, T. Fujinawa, N. Fukunishi, A. Goto, H. Hasebe, Y. Higurashi, E. Ikezawa, O. Kamigaito, M. Kase, M. Kobayashi Komiyama, H. Kuboki, K. Kumagai, T. Maie, M. Nagase, T. Nakagawa, J. Ohnishi, H. Okuno, N. Sakamoto, Y. Sato, K. Suda, M. Wakasugi, H. Watanabe, T. Watanabe, Y. Watanabe, Y. Yano, S. Yokouchi
  RIKEN, Wako, Saitama

The Ra­dioac­tive Iso­tope Beam Fac­to­ry at RIKEN Nishi­na Cen­ter is a next gen­er­a­tion fa­cil­i­ty which is ca­pa­ble of pro­vid­ing the world’s most in­tense RI beams over the whole range of atom­ic mass­es. Three new ring cy­clotrons have been con­struct­ed as post-ac­cel­er­a­tors for the ex­ist­ing fa­cil­i­ty in order to pro­vide the in­tense heavy ion beam for the RI beam pro­duc­tion by using a in-flight sep­a­ra­tion method. The beam com­mis­sion­ing of RIBF was start­ed at July 2006 and we suc­ceed­ed in the first beam ex­trac­tion from the final boost­er cy­clotron, SRC, by using 345 MeV/nu­cle­on alu­minum beam on De­cem­ber 28^th 2006. The first ura­ni­um beam with en­er­gy of 345 MeV/nu­cle­on was ex­tract­ed from the SRC on March 23^rd 2007. Var­i­ous mod­i­fi­ca­tions for equip­ments and many beam stud­ies were per­formed in order to im­prove the trans­mis­sion ef­fi­cien­cy and to gain up the beam in­ten­si­ty. Con­se­quent­ly, the world’s most in­tense 0.4 pnA ²³⁸U beam with en­er­gy of 345 MeV/nu­cle­on and 170 pnA ⁴⁸Ca beam with en­er­gy of 345 MeV/nu­cle­on have been pro­vid­ed for ex­per­i­ments.

Slides

• O. Kamigaito, S. Arai, M. Fujimaki, T. Fujinawa, H. Fujisawa, N. Fukunishi, A. Goto, Y. Higurashi, E. Ikezawa, T. Kageyama, M. Kase, M. Komiyama, H. Kuboki, K. Kumagai, T. Maie, M. Nagase, T. Nakagawa, J. Ohnishi, H. Okuno, N. Sakamoto, Y. Sato, K. Suda, H. Watanabe, T. Watanabe, Y. Watanabe, K. Yamada, H. Yamasawa, Y. Yano, S. Yokouchi
  RIKEN, Wako, Saitama

In 2008, the RIKEN RI-Beam Fac­to­ry (RIBF) suc­ceed­ed in pro­vid­ing heavy ion beams of ⁴⁸Ca and ²³⁸U with 170 par­ti­cle-nano-am­pere and 0.4 par­ti­cle-nano-am­pere, re­spec­tive­ly, at an en­er­gy of 345 MeV/u. The trans­mis­sion ef­fi­cien­cy through the ac­cel­er­a­tor chain has been sig­nif­cant­ly im­proved owing to the con­tin­u­ous ef­forts paid since the first beam in 2006. From the op­er­a­tional point of view, how­ev­er, the in­ten­si­ty of the ura­ni­um beam should be much in­creased. We have, there­fore, con­struct­ed a su­per­con­duct­ing ECR ion source which is ca­pa­ble of the mi­crowave power of 28 GHz. In order to re­duce the space-charge ef­fects, the ion source was in­stalled on the high-volt­age ter­mi­nal of the Cock­croft-Wal­ton pre-in­jec­tor, where the beam from the source will be di­rect­ly in­ject­ed into the heavy-ion linac by skip­ping the RFQ pre-in­jec­tor. The test of the ion source on the plat­form has start­ed re­cent­ly with an ex­ist­ing mi­crowave source of 18 GHz. This pre-in­jec­tor will be avail­able in Oc­to­ber 2009. We will show fur­ther up­grade plan of con­struct­ing an al­ter­na­tive in­jec­tor for the RIBF, con­sist­ing of the su­per­con­duct­ing ECR ion source, an RFQ, and three DTL tanks. An RFQ linac, which has been orig­i­nal­ly de­vel­oped for the ion-im­plan­ta­tion ap­pli­ca­tion will be reused for the new in­jec­tor. Mod­i­fi­ca­tion of the RFQ as well as the de­sign study of the DTL are under progress. The new in­jec­tor, which will be ready in FY2010, aims at in­de­pen­dent op­er­a­tion of the RIBF ex­per­i­ments and su­per-heavy el­e­ment syn­the­sis.

Slides

• N. Sakamoto, M. Fujimaki, A. Goto, O. Kamigaito, M. Kase, R. Koyama, K. Suda, K. Yamada, S. Yokouchi
  RIKEN, Wako

At RIKEN RIB-fac­to­ry (RIBF) an ac­cel­er­a­tor com­plex as an en­er­gy boost­er which con­sists of su­per­con­duct­ing ring cy­clotron (SRC), in­ter­me­di­ate-stage ring cy­clotron (IRC) and fixed-fre­quen­cy ring cy­clotron (FRC) pro­vides very heavy ion beams like ura­ni­um with an en­er­gy of 345 MeV/u. The total beam power ob­tained up to now at the SRC is as high as 3 kW in the case of ⁴⁸Ca with an in­ten­si­ty of 170 pnA. Re­cent­ly we have suc­ceed­ed in achiev­ing sta­ble and re­li­able op­er­a­tion of rf sys­tem for new cy­clotrons. In this paper the pre­sent per­for­mance of the rf sys­tem and a re­cent de­vel­op­ment is re­port­ed.

Slides