Ⅳ. OPERATION RECORDS
RIKEN
Accel. Prog. Rep. 56 (2023)

RIKEN Accel. Prog. Rep. 56 (2023)

Operation of Pelletron tandem accelerator
T. Ikeda,∗1 K. Inayoshi,∗2,∗1 and H. Sato∗1
The Pelletron tandem accelerator (5SDH-2) provides
ion beams accelerated by up to 1.7 MV for sample irradiation, material analysis, and developments of detectors used in RIBF. This accelerator is registered as a
joint-use equipment (ID: WE0429)1) at the Wako campus and is managed by the Detector Team of RNC.
Fig. 1 shows the conﬁguration of the accelerator, four
beam lines, and two ion sources. One ion source is
the RF charge-exchange type, referred to as Alphatross and is used to generate He− ions. The otheris the Source of Negative Ions by Cesium Sputtering(SNICS), which can generate almost all other negativeions. Till date, ion species of H, He, B, C, O, andAu have been mainly accelerated in the range of 0.5–
1.7 MV. For example, the energies of He2+ and 12 C6+
are 5.1 and 11.9 MeV, respectively, upon the application of 1.7 MV.

glass capillary5) and microbeam irradiation to induce
damage in DNA of mammalian cells.6) The productionof γ rays based on proton-induced resonance reactions
is available for a cross-section measurement in an international summer school, Nishina School, and for calibration of Ge detectors using high energy γ rays up
to 10.8 MeV. Although the 992-keV proton resonancein the reaction of 27 Al(p, γ)28 Si.7) BL-W30 was previously used for detector calibration;8) however, since2020, it has been dedicated to a new cell irradiation
port equipped with a glass capillary microbeam generator9–11) and an Olympus research microscope. Thisline has a unique feature to irradiate living cells in liquid medium with a short ion range (<100 µm) and astopping power (>200 keV/µm), which is suﬃciently
high to induce double strand breaks of DNA in cellnucleus.
The total machine time (MT) from January 1 toDecember 31, 2022, was 27 days as presented in Table 1. The MT included a machine study (MS) onacceleration, whereas excluded the conditioning of theion sources.
Table 1. Beam conditions.
Ion1Fig. 1. Pelletron tandem accelerator and beam lines at
Nishina R&D Building.

4

∗1
∗2

RIKEN Nishina Center
Department of Physics, Toho University- 211 -Beam current[particle nA]

ExperimentOperation time[days]

1.0–3.2

0.05–980

Irradiation

232+

2.28

5–58

RBS

3

1,2,3+

1.0–2.0

7

MS

1He

B

BL-E45 is dedicated to a sub-mm sized beam irradiation for samples in liquid.2) BL-E15 is used byusers in the ﬁeld of material science to perform Rutherford backscattering (RBS) spectrometry analysis3,4)
and elastic recoil detection analysis (ERDA). TheRBS/ERDA apparatus (Charles Evans and Associates
Model RBS-400) comprises a goniometer to rotate asample and particle detectors. Further, the detectors are located at backward and forward positions
to measure the energies of backscattered (He2+ ) ionsand recoiled particles from the sample, respectively.
The samples and the detectors are inside a vacuum
chamber with a vacuum level of the order of 10−4 Pa.
The intensity of the input He2+ beam of 2.28 MeV isgreater than 10 nA according to the collimated beam
size of 5–10 mm in diameter. On the west side, BLW15 is employed as a multipurpose line for variousequipment. Test systems have been constructed for
proﬁle measurements of ion microbeam produced byH+Energy[MeV]

The experiments performed in this facility are listed
below, along with the beam lines and number ofdays of MT. The Nishina School in 2022 was postponed.
(1) Microbeam performance study with H ions using
glass capillaries at BL-W15 and -W30 (9 days)(2) RBS/ERDA experiments at BL-E15 (4 days)(3) Educational experiment of proton capture bycarbon/boron-nucleus for the Nishina School (0days)(4) Development of a charged-particle/γ-ray detector to be used for RIBF experiments including
MS (14 days)
The ﬂuctuation of the acceleration voltage of thePelletron improved from 2 to 0.1% following the overhaul from February to March. The achieved stability
was the best in the last decade and realized the beam
position ﬂuctuation of less than 1 mm (beam size is10–20 mm) at the samples.

Ⅳ. OPERATION RECORDS

RIKEN Accel. Prog. Rep. 56 (2023)

References
1) Research support system, R-COMS (RIKEN ID is necessary), https://riken.simprent.jp/2) T. Kobayashi et al., Surf. Coat. Technol. 331, 206(2017).
3) L. Jianjun et al., Chem. Sci. 12, 10354 (2021).
4) S. R. Lee et al., Phys. Status Solidi A 219, 23, 2200318(2022).
5) T. Ikeda et al., Nucl. Instrum. Methods Phys. Res. B
470, 42 (2020).
6) T. Ikeda et al., RIKEN Accel. Prog. Rep. 53, 215(2020).
7) R. Mizuno et al., RIKEN Accel. Prog. Rep. 55, S20(2022).
8) F. P. Gustafsson et al., RIKEN Accel. Prog. Rep. 50,209 (2017).
9) T. Ikeda, Jpn. Soc. Appl. Phys. Rev. 2022, 220205(2022).
10) K. Inayoshi et al., RIKEN Accel. Prog. Rep. 55, 107(2022).
11) M. Kurino et al., in this report.

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