II-1. Nuclear Physics

RIKEN Accel. Prog. Rep. 54 (2021)

RIKEN Accel. Prog. Rep. 54 (2021)

Particle identification of SAMURAI11 experiment
J. Gao,∗1,∗3 M. Sasano,∗1 L. Stuhl,∗6,∗2 Y. Hirai,∗4 T. Wakasa,∗4 D. S. Ahn,∗1 J. K. Ahn,∗13 H. Baba,∗1K. Chae,∗20 A. Chilug,∗5,∗1 K. Cook,∗15 Y. Fujino,∗7 N. Fukuda,∗1 B. Gao,∗19 S. Goto,∗4 I. S. Hahn,∗6,∗8Y. Hamano,∗4 Z. Halász,∗9 T. Harada,∗10 S. Hong,∗20 S. Huang,∗1,∗3 N. Inabe,∗1 D. Inomoto,∗4 T. Isobe,∗1H. Kasahara,∗4 D. Kim,∗6,∗8 T. Kobayashi,∗14 Y. Kondo,∗15 Z. Korkulu,∗6,∗1 A. J. Krasznahorkay,∗9 H. Miki,∗15
K. Miki,∗14 S. Mitsumoto,∗4 M. Miwa,∗18 T. Motobayashi,∗1 T. Nakamura,∗15 M. Nishimura,∗1 H. Oshiro,∗4H. Otsu,∗1 V. Panin,∗1 S. Sakaguchi,∗4 D. Sakai,∗14 H. Sakai,∗1 S. Sakaki,∗4 H. Sato,∗1 T. Shimada,∗15
Y. Shimizu,∗1 B. Sun,∗21 X. Sun,∗1,∗3 H. Suzuki,∗1 J. Tanaka,∗1 Y. Togano,∗7 T. Tomai,∗15,∗1 T. Uesaka,∗1Y. Utsuki,∗14 H. Wang,∗15 X. Xu,∗19 K. Yako,∗2 A. Yasuda,∗15 K. Yoneda,∗1 K. Yoshida,∗1 Y. Yoshitome,∗15and J. Zenihiro∗1In this report, we present the particle identiﬁcation (PID) results of the decay fragments from the48
Cr(p, n)48 Mn reaction in the SAMURAI11 experiment.1)
The charge number Z and mass to charge ratio
A/Z are used to identify particles, where Z is calculated using the energy loss ∆E and time-of-ﬂight measured in the hodoscope and A/Z is calculated using
the rigidity and ﬂight path from the simulation andthe time-of-ﬂight. With the position and angle information from the drift chambers before and after theSAMURAI magnet, the rigidity and trajectory of theparticle could be extracted by simulation. The simulation program uses a 4th-order Runge-Kutta method
to simulate the trajectory and it iterates several times
to determine the rigidity that reproduces the position
and angle measured in the drift chambers.
Our hodoscope detector consists of seven bars. The
size of each bar is 1200 mm(H) × 100 mm(W) ×10 mm(T). The PID in one hodoscope bar is shownin Fig. 1. Because the position on the PID plot of one
particle could be slightly shifted in diﬀerent bars, weevaluate the resolution on one bar only. The resolutionof the charge number Z is σZ,48 Cr = 0.20 and σZ,46 V= 0.19, corresponding to 5.0σ separation for Z = 23and Z = 24. The resolution of the mass to charge ratio A/Z is σA/Z,46 V = 0.0099 and σA/Z,47 V = 0.0083,

corresponding to 4.3σ separation.
This work was funded by the China ScholarshipCouncil, KAKENHI project 16H06716, the Japan Society for the Promotion of Science, and Kurata Grantfrom the Kurata Memorial Hitachi Science and Technology Foundation.

30CrV44Ti

48

2547

Z46

Vcount
150

20100
50

15

10
1.9

2.0

A/Z

2.1

2.2Fig. 1. PID in one bar of hodoscope. This bar is the one
next to the bar hitting by beam particles, on the higher
rigidity side. Some particles are labeled on the figure.

∗1RIKEN Nishina Center∗2 Center for Nuclear Study, University of Tokyo∗3 School of Physics, Peking University∗4 Department of Physics, Kyushu University∗5 Horia Hulubei Nat. Inst. of Phys. and Nucl. Eng.
∗6 Center for Exotic Nuclear Studies, Institute for Basic Science∗7 Department of Physics, Rikkyo University∗8 Department of Physics, Ewha Womans University∗9 ATOMKI, Institute for Nuclear Research∗10 Department of Physics, Toho University∗11 KVI - CART, University of Groningen∗12 GSI Helmholtzzentrum für Schwerionenforschung GmbH
∗13 Department of Physics, Korea University∗14 Department of Physics, Tohoku University∗15 Dept. of Physics, Tokyo Institute of Technology∗16 Department of Physics, University of Tokyo∗18 Dept. of Physics, Saitama University∗19 Institute of Modern Physics, Chinese Acad. of Sci.
∗20 Department of Physics, Sungkyunkwan University∗21 School of Physics and Nuclear Engineering, Beihang University

Reference1) M. Sasano et al., RIKEN Accel. Prog. Rep. 53, 40(2019).

- 14 -1