• K. Yamada, S. Arai, M.K. Fujimaki, T. Fujinawa, N. Fukunishi, A. Goto, Y. Higurashi, E. Ikezawa, O. Kamigaito, M. Kase, M. Komiyama, K. Kumagai, T. Maie, T. Nakagawa, J. Ohnishi, H. Okuno, N. Sakamoto, Y. Sato, K. Suda, H. Watanabe, Y. Watanabe, Y. Yano, S. Yokouchi
  RIKEN Nishina Center, Wako
• H. Fujisawa
  Kyoto ICR, Uji, Kyoto

A new ad­di­tion­al in­jec­tor (RI­LAC2) is con­struct­ed at RIKEN Nishi­na Cen­ter in order to en­able the in­de­pen­dent op­er­a­tion of the RIBF ex­per­i­ments and su­per-heavy el­e­ment syn­the­sis. The RI­LAC2 con­sists of a 28 GHz su­per­con­duct­ing ECR ion source, a low-en­er­gy beam trans­port with a pre-bunch­er, a four-rod RFQ linac, a re­bunch­er, three DTL tanks, and strong Q-mag­nets be­tween the rf res­onators for the trans­verse fo­cus­ing. Very heavy ions with m/q of 7 such as ¹³⁶Xe²⁰⁺ and ²³⁸U³⁵⁺ will be ac­cel­er­at­ed up to the en­er­gy of 680 keV/u in the cw mode and be in­ject­ed to the RIKEN Ring Cy­clotron with­out charge strip­ping. The RFQ linac, the last tank of the DTL, and the bunch­ers have been con­vert­ed from old ones in order to save the cost. Con­struc­tion of the RI­LAC2 start­ed at the end of the fis­cal 2008. The RFQ and DTLs will be in­stalled in the AVF cy­clotron vault and be test­ed in March 2010. The ECR ion source and low-en­er­gy beam trans­port will be set on the RI­LAC2 in 2010 sum­mer, and the first beam will be ac­cel­er­at­ed in 2010 au­tumn. We will pre­sent the de­tails of the linac part of RI­LAC2 as well as the progress of con­struc­tion which in­cludes the re­sult of high power test of res­onators.

• Y. Sato, M.K. Fujimaki, N. Fukunishi, A. Goto, Y. Higurashi, E. Ikezawa, O. Kamigaito, M. Kase, T. Nakagawa, J. Ohnishi, H. Okuno, H. Watanabe, Y. Watanabe, S. Yokouchi
  RIKEN Nishina Center, Wako

The RI beam fac­to­ry at RIKEN Nishi­na Cen­ter needs high in­ten­si­ty of ura­ni­um ion beams. We con­struct­ed a new in­jec­tor, RI­LAC2, which would pro­vide sev­er­al hun­dred times high­er in­ten­si­ty. As a part of the RI­LAC2, we de­signed the low en­er­gy beam trans­port, LEBT, from the su­per­con­duct­ing ECR ion source to the RFQ en­trance. In this paper we pre­sent its re­quire­ments and prob­lems, and show our de­sign as the so­lu­tions to them. Es­pe­cial­ly we focus a tech­nique of a pair of two solenoids to treat a ro­ta­tion­al op­er­a­tion and a fo­cus­ing op­er­a­tion in­de­pen­dent­ly. Based on this de­sign, the LEBT was com­plet­ed in March 2010. The RI­LAC2 will be op­er­a­tional this fall.

• Y. Sato, M.K. Fujimaki, N. Fukunishi, A. Goto, Y. Higurashi, E. Ikezawa, O. Kamigaito, M. Kase, T. Nakagawa, J. Ohnishi, H. Okuno, H. Watanabe, Y. Watanabe, S. Yokouchi
  RIKEN Nishina Center, Wako

The RI beam fac­to­ry at RIKEN Nishi­na Cen­ter needs high in­ten­si­ty of ura­ni­um ion beams. We have used so far the RFQ pre-in­jec­tor up­stream of the linac sys­tem, in which the ex­trac­tion volt­age of the ECR ion source is as low as 5.7 kV for the ura­ni­um beam. How­ev­er, for much high­er in­ten­si­ty beams from a newly de­vel­oped su­per­con­duct­ing ECR ion source, such a low volt­age was ex­pect­ed to sig­nif­i­cant­ly in­crease their emit­tance due to the space charge ef­fect. To re­duce this ef­fect, we pre­pared a new pre-in­jec­tor line of 127 kV for ura­ni­um beams by plac­ing the ion source on a high-volt­age ter­mi­nal. In this paper we pre­sent the de­sign of the 127 kV medi­um en­er­gy beam trans­port, MEBT, and show the mea­sured re­sults through the line.

• Y. Higurashi, M.K. Fujimaki, A. Goto, E. Ikezawa, O. Kamigaito, M. Kase, M. Komiyama, T. Nakagawa, J. Ohnishi, Y. Watanabe
  RIKEN Nishina Center, Wako
• T. Aihara, M. Tamura, A. Uchiyama
  SHI Accelerator Service Ltd., Tokyo

The next gen­er­a­tion heavy ion ac­cel­er­a­tor fa­cil­i­ty, such as the RIKEN RIBF, re­quires great va­ri­ety of high charged heavy ions with a mag­ni­tude high­er beam in­ten­si­ty than cur­rent­ly achiev­able. In the last decade, per­for­mance of the ECR ion sources has been dra­mat­i­cal­ly im­proved with in­creas­ing the mag­net­ic field and RF fre­quen­cy to en­hance the den­si­ty and con­fine­ment time of plas­ma. Fur­ther­more, the ef­fects of the key com­po­nents (mag­net­ic field con­fig­u­ra­tion, gas pres­sure etc) on the ECR plas­ma have been re­vealed. Such basic stud­ies give us how to op­ti­mize the ion source struc­ture. Based on these stud­ies and the tech­nol­o­gy, we suc­cess­ful­ly con­struct­ed the new 28GHz SC-ECRIS which has a flex­i­ble mag­net­ic field con­fig­u­ra­tion to en­large the ECR zone and to op­ti­mize the field gra­di­ent at ECR point. In the test ex­per­i­ment, we ob­tained the di­rect ev­i­dence that the field gra­di­ent and the zone size strong­ly af­fect the beam in­ten­si­ty. It con­cludes that the gen­tler field gra­di­ent and large ECR zone size gives in­tense beam of high­ly charged heavy ions from ECR plas­ma. In this con­tri­bu­tion, we re­port the sys­tem­at­ic study of these ef­fects on the beam in­ten­si­ty of high­ly charged heavy ions.