Ⅱ-9. Instrumentation

RIKEN Accel. Prog. Rep. 49 (2016)

Online results for the injection ion optics of the Rare RI Ring
Z. Ge,∗1,∗2 Y. Abe,∗1 F. Suzaki,∗1,∗2 D. Nagae,∗1 S. Naimi,∗1 T. Uesaka,∗1 Y. Yamaguchi,∗1 T. Yamaguchi,∗2A. Ozawa,∗3 H. Miura,∗2 S. Omika,∗2 Y. Takeuchi,∗2 S. Suzuki,∗3 Y. Yano∗1 for the Rare RI Ring collaboration
The Rare RI Ring (R3) is a cyclotron-like storage
ring designed for mass measurements of exotic nuclei
far from stability at Radioactive Ion Beam Factory inRIKEN1) . In order to successfully transport the nuclei of interest individually1) to the central orbit of theRare RI Ring, we calculated the injection ion optics
for the Rare RI Ring beam line, which connects theRare RI Ring spectrometer to the BigRIPS separator. For the upstream optics from F3 to S0 , the target
position of the SHARAQ spectrometer, the standard
high-resolution achromatic mode is used2) . The total optical matrix is calculated from S0 to the kicker
magnet position3) , and two important foci, ILC1 andILC2, are shown in Fig. 1, where 2 PPACs are placedto evaluate the matrix elements for beam tuning quantitatively.

Table 1. Currents (CSQ1−3 and CQ1−10 ) of the quadrupolemagnets (SQ1-3 and Q1-10) of the injection lineCondition
FDFDF
FDF
DFDF
D

During online beam tuning, we chose the configuration of the three SHARAQ quadrupoles (SQ1-3)2)
and the ten quadrupoles (Q1-10) between ILC1 andILC2 to be FDF-DF-FDF-DFDF-D (D indicts indicates “Defocus” and F indicates “Focus”) configuration in the lateral direction, which is suited for thesmall vertical acceptance as shown in Fig. 1 (bottom) for fast tuning of the beam. To complete thefast tuning method developed for SHARAQ spectrometer2) , we first design the optics of the injection linewith many focus planes. Then we calculate the re∗1
∗2
∗3

RIKEN Nishina Center
Department of Physics, Saitama University
Institute of Physics, University of Tsukuba- 180 -EXP. (A)
33.28
61.20
61.59
226.8
715.4
200.9

Cal. (A)
33.1
61.0
61.3
480.8
723.8
295.7

25.8

27.4

Table 2. Matrix elements of ILC1 and ILC2 evaluatedfrom the experiment and calculated by COSY INFINITY
MatrixElement(x| a)(y| b)

Fig. 1. Envelopes of the beam transport from SHARAQ S0to kicker magnet in the horizontal and vertical plane by
third order calculation using COSY INFINITY.

Configuration
CSQ1-CSQ2
CSQ3-CQ1 =CQ2
CQ3 =-CQ4 =CQ5-CQ6 =CQ7 =-CQ8=CQ9-CQ10EXP.
(ILC1)
0.02±0.007
5.40±0.007

Cal.
(ILC1)
00EXP.
(ILC2)
0.19 ± 0.010−6.66±0.010

Cal.
(ILC2)
0.04-0.07

sponse functions of each quadruple magnet by COSY
INFINITY. During beam tuning, we cancelled themomentum-dispersion effects by combining information at the dispersive focal plane. Once the matrix
elements of the experimental values are evaluated, it isused for correcting the magnet setting precisely.
We performed the tuning method using the designed
ion-optical mode for the first commissioning run ofRare RI Ring in June 2015, for which we use the78
Kr36+ beam with the energy of 168 MeV/nucleon.
With this ion-optical mode we successfully carried out
the individual injection of the Rare RI Ring, and wesucceeded in storing the 78 Kr36+ ions for a few seconds.
Table 1 indicates the measured magnet current
values and their corresponding calculated values via
COSY INFINITY (the magnetic fields corresponding
to the currents of the magnets here). The transfer matrix element of the two important focal planes ILC1and ILC2 are listed in Table 2. The measured valuesof the matrix elements after beam tuning are consistent with the calculated values for the horizontal direction, while they differ in the vertical direction due
to a misalignment in the beamline.
References1) A. Ozawa et al., Prog. Theor. Exp. Phys. 03C009, 2012.
2) T. Uesaka et al., Prog. Theor. Exp. Phys. 03C007, 2012.
3) Y. Yamaguchi et al., Nucl. Instrum. Methods Phys. Res.
B 317, 629 (2013).