IV. OPERATION RECORDS

RIKEN Accel. Prog. Rep. 54 (2021)

RIKEN Accel. Prog. Rep. 54 (2021)

Operation report on the RIKEN AVF cyclotron for 2020
M. Nishida,∗1 K. Ozeki,∗2 M. Fujimaki,∗2 N. Fukunishi,∗2 S. Fukuzawa,∗1 A. Goto,∗2 H. Hasebe,∗2M. Hamanaka,∗1 Y. Higurashi,∗2 E. Ikezawa,∗2 H. Imao,∗2 S. Ishikawa,∗1 K. Kamakura,∗3 O. Kamigaito,∗2
M. Kase,∗2 M. Kidera,∗2 K. kobayashi,∗1 M. Komiyama,∗2 Y. Kotaka,∗3 R. Koyama,∗1 K. Kumagai,∗2 T. Maie,∗2T. Nagatomo,∗2 T. Nakagawa,∗2 T. Nakamura,∗1 M. Nishimura,∗1 J. Ohnishi,∗2 H. Okuno,∗2 Y. Oshiro,∗3N. Sakamoto,∗2 J. Shibata,∗1 K. Suda,∗2 N. Tsukiori,∗1 A. Uchiyama,∗2 S. Watanabe,∗2 T. Watanabe,∗2Y. Watanabe,∗2 K. Yadomi,∗1 and K. Yamada∗2
The yearly report on the operation of the RIKEN
AVF cyclotron (denoted as AVF hereafter) for the period January-December 2020 is presented. AVF delivered beams to five courses for stand-alone operations:
C01 (machine study), C03 (radioactive isotope (RI) production), C12 (CNS, RI production), E7A (CRIB), andE7B (RI production, student experiment). On the otherhand, when AVF was used as an injector of the RIKEN
Ring Cyclotron (RRC), beams were delivered to twocourses: RRC-RARF and RRC-IRC-E5. Figure 1 showsthe experimental apparatuses around AVF.
Thus far, AVF was equipped with three ion sources
to deliver various ion beams: the superconducting electron cyclotron resonance ion source (SC ECRIS), HyperECRIS, and polarized ion source (PIS, only used for polarized deuterons). However, a GM refrigerator used forcooling the superconducting mirror coils in SC ECRIS
had become too old. Therefore, SC ECRIS was replacedwith the 18 GHz ECRIS that had been used at RILAC,
and beam deliveries from the 18 GHz ECRIS commenced
in January.
The yearly operation statistics are presented in Tables 1 and 2. In a total operation time of 2702 h, 1520 h
was spent for stand-alone operation, and 1182 h wasspent for injection to RRC. Because of the declaration ofa state of emergency due to the COVID-19 outbreak, allbeam times scheduled for April and May were canceled.

This is a main reason why the operation time for standalone operation in this year is considerably less than thatin the previous year. In addition, an RI production experiment using 30-MeV protons was conducted for thefirst time in June.
Table 1. Comparison of AVF operation statistics with thatin the previous year.
AVF stand-alone operation
Tuning of AVF[h]Trouble of AVF [h]C01 M. S.
[h]C03 exp.
[h]
C12 exp.
[h]
E7A exp.
[h]
E7B exp.
[h]
Sub total[h]
AVF operation as injector of RRC
Tuning of AVF[h]Trouble of AVF [h]RRC-RARF exp. [h]RRC-RIBF exp. [h]Sub total[h]Total[h]2019131400873
36789
1523166
2019
1170320
0437
3603

2020
744
112631
1812101
1520
2020
178
599901182
2702

Table 2. AVF beam list in 2020.
Energy(MeV/nucleon)
Stand-alone operation
Particle

Course

p
12.00
C03
p
19.00
C12p
30.00
C01, C03
d
12.00
C03
α
6.50
E7B
α
7.25
C03, E7B
α
12.50
C03
7Li
6.00
C03
16O
6.80
E7A
18O
7.00
C1219
F
6.30
C03
Operation as injector of RRC
CN
20
Ne
22Ne
40
Ar
40Ar
56Fe84Kr
1214

Fig. 1. Overview of the AVF cyclotron with ion sources, eachexperimental course, and beam transport line to RRC.
∗1
∗2∗3

SHI Accelerator Service Ltd.
RIKEN Nishina Center
Center for Nuclear Study, the University of Tokyo- 185 -

7.00
7.00
7.00
3.97
3.80
5.20
5.00
3.97

RRC-RARF
RRC-RARF
RRC-RARF
RRC-RARF
RRC-IRC-RARF
RRC-RARF
RRC-RARF
RRC-RARF

1