Ⅱ-3. Nuclear Data

RIKEN Accel. Prog. Rep. 56 (2023)
RIKEN
Accel. Prog. Rep. 56 (2023)

Measurement of isotopic production cross section on 99 Tc via protonand deuteron-induced reactions
R. Matsumura,∗1,∗2 H. Otsu,∗1 H. Wang,∗3 H. Sakurai,∗1 D. Nishimura,∗4 H. Takahashi,∗4 S. Takeshige,∗5
M. Tanaka,∗1 and Y. Togano∗1,∗5 for the RIBF-TM2021 Collaboration
resolution was 0.80%, not achieving even 3σ separation.
This is probably because the integration time of theF11IC5) Shaping Amp. was unintentionally adjusted tobe too short. Although the identiﬁcation resolution isinsuﬃcient compared to the previous experiments, theyield can be counted up with the superposition of 2-D
Gaussian functions.
Moreover, the Ru isotopes from the 99 Tc beam arescarcely observed in the region indicated by the dashedline in Fig. 1. It was conﬁrmed that the Ru and Tc
isotopes with large pulse heights were overﬂowing insome or all of the ADCs with 6 channel readout. The
number of overﬂowed channels causes a diﬀerence in thepeak position of each isotope in the A/Q spectrum. InFig. 2, the A/Q spectrum is plotted for that overﬂow
bit information. The peaks indicated in the blue curve
are almost consistent with the unique A/Q of the Tcisotopes. Whereas the red curve is considered to be
the sum of both responses because it has a peak inthe middle of each A/Q of Tc and Ru. We plan todecompose the red curve into each response from thestrictly deﬁned A/Q peak positions.
300Counts

In order to evaluate the reactions of the long-lived
ﬁssion products (LLFPs) with neutron, we have measured systematically the proton- and deuteron-induced
cross sections for 90 Sr,1) 137 Cs,1) 93 Zr,2) 107 Pd,3) etc.
As a next step, we started a study on 99 Tc, which isknown to be one of the LLFPs.
A secondary beam including 99m Tc was produced by
the in-ﬂight ﬁssion of 238 U at 345 MeV/nucleon on a3-mm-thick 9 Be target, selected and identiﬁed eventby-event using the TOF-Bρ-∆E method4) in BigRIPS.
It also included 99m Tc (T1/2 = 6 h), which is indistinguishable by the same method, was irradiated to a3-mm-thick Al plate and studied for the production ratio by in-ﬂight ﬁssion using the Ge detector. Cocktail
beams of 99 Tc and 99m Tc at 114 MeV/nucleon werebombarded with CH2 , CD2 , and C reaction targets
placed at the entrance of ZD spectrometer (ZDS). The
residual nuclei produced in the reactions were identiﬁed in ZDS. Since the momentum acceptance of ZDS islimited to ±3%, the measurement was conducted using
5 diﬀerent momentum settings (∆ (Bρ) /Bρ = −9, −6,−3, 0, and +3%) for each target to accept a wide rangeof the mass-to-charge ratio A/Q.
Figure 1 shows particle identiﬁcation of residual nuclei was realized by combining A/Q and atomic numberZ, derived from the measured information in ZDS. TheA/Q (relative RMS) resolution was 0.20%, which corresponds to 5.4σ separation. On the other hand, the Z

Tc

200
100

Atomic number ZF1145
44

Ru

43

Tc

42

Mo

41

Nb40

Zr

39

Y

38
2.1

2.15

2.2
2.25
2.3
Mass-to-charge ratio A/QF9-F1102.1

10

∗2∗3
∗4
∗52.15

2.2

2.25

2.3

2.35

Mass-to-charge ratio A/QF9-F11Fig. 2. A/Q spectra showing the dashed line region in Fig. 1,
these are imposed overﬂow bit = 5, 6 for red curve and
1 for blue curve.

1We have started a new study of proton- and deuteroninduced cross sections on 99 Tc. After the analysis
method is ﬁnalized, the other remaining targets will
be analyzed.

10−1
2.35

References

Fig. 1. Particle identiﬁcations of residual nuclei wereproduced in reactions with the CH2 target at the∆ (Bρ) /Bρ = −6% setting on ZDS.
∗1Ru+Tc

RIKEN Nishina Center
Department of Physics, Saitama University
RIKEN Cluster for Pioneering Research
Department of Natural Sciences, Tokyo City University
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317, 323 (2013).
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