Ⅱ-1. Nuclear Physics

RIKEN Accel. Prog. Rep. 53

Calibration and simulation of LaBr3 :Ce scintillator for analyzing
8Li(α, n)11 B-reaction data
Y. Mizoi,∗1,∗2,∗3 H. Baba,∗3 A. Bracco,∗4,∗5 F. Camera,∗4,∗5 S. M. Cha,∗6 K. Y. Chae,∗6 S. Cherubini,∗3,∗7,∗8
H. S. Choi,∗9 N. N. Duy,∗6 T. Fukuda,∗3,∗10 S. Hayakawa,∗2 Y. Hirayama,∗11 N. Imai,∗2 H. Ishiyama,∗3 A. Kim,∗12D. H. Kim,∗6 N. Kitamura,∗2 S. Kubono,∗2,∗3 M. S. Kwag,∗6 S. Michimasa,∗2 M. Mihara,∗3,∗13 H. Miyatake,∗11S. Ota,∗2 R. G. Pizzone,∗7 H. Shimizu,∗2,∗3 N. K. Uyen,∗6 R. Wakabayashi,∗3,∗13 Y. X. Watanabe,∗11O. Wieland,∗4 H. Yamaguchi,∗2 L. Yang,∗2 N. Zhang,∗2,∗14 and Z. C. Zhang∗14
single escape and double escape are consistent with thesimulated ones. By applying the results of our precise
energy calibration, we can proceed to the data analysis
for solving the discrepancies among the previous results.

Energy (keV)

9000
8000

Table 1. Gamma-ray sources used for oﬀ-line calibration andtheir energies.
SourceCs
Am/Be(12 C∗ )Cm/C(16 O∗ )Am/Be+Al
137

Energy (keV)

R² = 0.9999

7000
6000
5000
4000
3000
2000
1000
0170

190

210

230
TDC channel

250

Fig. 1. Calibration plot obtained by oﬀ-line measurements.

Counts

We performed an experiment1) using LaBr3 :Ce scintillators2) at CRIB in 2018 for investigating controversial large diﬀerences among the previously reported3–9)
cross-section data of the 8 Li(α, n)11 B reaction. In order to resolve the discrepancies among them, it is essential to obtain an accurate γ-ray spectrum of 11 B;therefore, accurate energy calibration and precise eﬃciency estimation play a crucial role. We performed oﬀline measurements for energy calibration using radiation
sources, as listed in Table 1. Figure 1 presents the calibration plot, in which the horizontal and vertical axes
correspond to the time-to-digital converter (TDC) channel reduced by a charge-to-time converter (QTC) andthe expected γ-ray energy, respectively; the plot shows
suﬃciently good linearity. On-line measurements using
16
N beams were also performed at CRIB. In the studiedreaction, 16 N decays to 16 O∗ , which emits γ-rays withEγ = 6130 keV. GEANT4 simulations were also performed for each type of γ-rays. One example is shownin Fig. 2, which is the preliminary result of the γ-ray
energy spectrum of 16 N(βγ). The histogram with error
bars and ﬁlled histogram are measured and simulated
spectra, respectively. The measured peaks of full energy,

30252015662
4440
6130
7724

1050

∗1

Center for Physics and Mathematics, Institute for Liberal Artsand Sciences, Osaka Electro-Communication University∗2 Center for Nuclear Study, the University of Tokyo∗3 RIKEN Nishina Center∗4 INFN - Sezione di Milano∗5 Dipartimento di Fisica dell’Università degli Studi di Milano∗6 Department of Physics, Sungkyunkwan University∗7 INFN - Laboratori Nazionali del Sud (LNS)∗8 Dipartimento di Fisica ed Astronomia, Università di Catania∗9 Department of Physics and Astronomy, Seoul National University∗10 RCNP, Osaka University∗11 Wako Nuclear Science Center (WNSC/IPNS), KEK∗12 Department of Physics, Ewha Womans University∗13 Department of Physics, Osaka University∗14 IMP, Chinese Academy of Science (CAS)- 54 -4600

4800

5000

5200

5400

5600

58006000

6200 6400
Energy (keV)

Fig. 2. Energy spectrum of γ-rays from 16 N(βγ).

References

1) Y. Mizoi et al., RIKEN Accel. Prog. Rep. 52, 58 (2019).
2) A. Gaiz et al., Nucl. Instrum. Methods Phys. Res. A 729,910 (2013).
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6) S. Cherubini et al., Eur. Phys. J. 20, 355 (2004).
7) H. Ishiyama et al., Phys. Lett. B 640, 82 (2006).
8) M. La Cognata et al., Phys. Lett. B 664, 157 (2008).
9) S. K. Das et al., Phys. Rev. C 95, 055805 (2017).