• K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, K. Nagayama, H. Okamura, T. Saito, H. Tamura, T. Yorita
  RCNP, Osaka

The RCNP ac­cel­er­a­tor cas­cade　con­sists of an in­jec­tor Az­imuthal­ly Vary­ing Field (AVF) cy­clotron (K=140) and a ring cy­clotron (K=400). It pro­vides ul­tra-high-qual­i­ty beams and mod­er­ate­ly high-in­ten­si­ty beams for a wide range of re­search in nu­cle­ar physics, fun­da­men­tal physics, ap­pli­ca­tions, and in­ter­dis­ci­plinary fields. The max­i­mum en­er­gy of pro­tons and heavy ions are 400 and 100 MeV/u, re­spec­tive­ly. Ex­per­i­men­tal ap­pa­ra­tus­es are used like a pair spec­trom­e­ter, a neu­tron time of flight fa­cil­i­ty with a 100 m long tun­nel, a ra­dioac­tive nu­clei sep­a­ra­tor, a su­per-ther­mal ultra cold neu­tron (UCN) source, a white neu­tron source, and a RI pro­duc­tion sys­tem for nu­cle­ar chem­istry. Such ultra high res­o­lu­tion mea­sure­ments as dE/E = 5x10-5 are rou­tine­ly per­formed with the Grand-Raiden spec­trom­e­ter by uti­liz­ing the dis­per­sion match­ing tech­nique. The UCN den­si­ty was ob­served to be 15 UCN/cm³ at the ex­per­i­men­tal port at a beam power of 400 W. Some top­ics on the re­search are dis­cussed in the talk.

• K. Hatanaka, M. Fukuda, J. Nakagawa, T. Saito, T. Yorita
  RCNP, Osaka
• T. Kawaguchi
  KT Science Ltd., Akashi
• K. Noda
  NIRS, Chiba-shi
• Y. Sakemi
  CYRIC, Sendai

A scan­ning mag­net using high-tem­per­a­ture su­per­con­duc­tor (HTS) wire was de­signed, fab­ri­cat­ed, and test­ed for its suit­abil­i­ty as beam scan­ner. After suc­cess­ful cool­ing tests, the mag­net per­for­mance was stud­ied using DC and AC cur­rents. With DC cur­rent the mag­net was suc­cess­ful­ly op­er­at­ed to gen­er­ate de­signed field dis­tri­bu­tions and ef­fec­tive length. In AC mode, the mag­net was op­er­at­ed at fre­quen­cies of 30-59 Hz and a tem­per­a­ture of 77 K as well as 10-20 Hz and 20K. The power loss dis­si­pat­ed in the coils was mea­sured and com­pared with the model cal­cu­la­tions. The ob­served loss per cycle was in­de­pen­dent of the fre­quen­cy and the scal­ing law of the ex­ci­ta­tion cur­rent was con­sis­tent with the­o­ret­i­cal pre­dic­tions for hys­teretic loss­es in HTS wires.

• M. Fukuda, K. Hatanaka, H. Kawamata, M. Kibayashi, T. Saito, H. Tamura, T. Yorita
  RCNP, Osaka

An up­grade pro­gram of the RCNP cy­clotron fa­cil­i­ty for in­crease of beam in­ten­si­ty and im­prove­ment of beam qual­i­ty is in progress to meet re­quire­ments from re­search in nu­cle­ar physics and in­dus­tri­al ap­pli­ca­tions using sec­on­dar­i­ly pro­duced par­ti­cles such as neu­trons, muons and ra­dioiso­topes. A 2.45 GHz ECR ion source using a set of per­ma­nent mag­nets was de­vel­oped for high in­ten­si­ty pro­ton beam pro­duc­tion. The pro­ton beam in­ten­si­ty more than 0.5 mA at an ex­trac­tion en­er­gy of 15 keV has been ob­tained with a pro­ton ratio more than 80 %. The qual­i­ty of the pre-ac­cel­er­at­ed beam from the K140 in­jec­tor AVF cy­clotron has been im­proved by a flat-top(FT) ac­cel­er­a­tion sys­tem to en­hance the beam trans­mis­sion to the K400 ring cy­clotron. Transver­sal res­o­nant mode of a dee elec­trode with a span angle of 180 de­grees was in­ves­ti­gat­ed to achieve the FT ac­cel­er­a­tion in the fre­quen­cy re­gion from 50 to 60 MHz. In this paper, de­vel­op­ments for high in­ten­si­ty pro­ton beam ac­cel­er­a­tion and beam qual­i­ty im­prove­ment using the FT ac­cel­er­a­tion sys­tem of the AVF cy­clotron will be main­ly pre­sent­ed.