Ⅲ-3. Radiochemistry & Nuclear Chemistry

RIKEN Accel. Prog. Rep. 49 (2016)

induced crossand enrichedenriched
Alpha particle induced
cross section
section measurements on natural andCd at
at 50 MeV
MeVCd
F. Ditrói,᧦1 S. Takács,᧦1 H. Haba,᧦2 Y. Komori,᧦2 M. Aikawa,᧦3, * 2 Z. Szűcs,᧦1 and M. Saito᧦4, * 2
In year 2015 two series of measurements have been
performed in January and December at the AVF cyclotronof RIKEN Nishina Center in the frame of a bilateralagreement between the Hungarian Academy of Sciences
and the Japan Society for the Promotion of Science. One ofthose series was the investigation of alpha particle induced
cross sections on natCd and enriched 116Cd targets. Theenergy of the alpha beam was calibrated by using Time of
Flight (TOF) methods before the December experiments.
The results of this was also used to correct the results of theJanuary experiments, because it turned out that the nominal
50 MeV alpha energy provided by the accelerator actuallycorresponds to 51.2 MeV energy. The enriched cadmium
was deposited on Cu backing while the natural cadmium
foils were pure metal foils from季 Goodfellow. In both
irradiations we used thin Ti foils for monitoring the beam
parameters, while in the enriched cadmium experiments
also the Cu backing served as monitor.
The radioisotope 117mSn with 13.6 d half-life, which has
already been used as a bone cancer pain relief agent, turned
to be more important in medical applications. 117mSn has
several advantages in modern cancer therapy. It has
conversion electron radiation with an average energy of 140
keV allowing about 300 Pm effective treatment range, thehalf-life is convenient for production, labelling and delivery
within several hundreds of kilometers, its 159 keV gammaline is also convenient for using the commercial imaging
techniques e.g. gamma camera. Taking into account allthese properties 117mSn is a unique candidate between all
potential medical isotopes1).
The first stack was assembled from enriched 116Cd
deposited on 12 Pm Cu backing. The average thickness of
the Cd layer was measured as 21.9 Pm. For further
monitoring several Ti foils with nominal thickness of 12 Pm
were also inserted between the Cd targets.
The alpha induced cross sections on both natural andenriched 116Cd and natCd targets have already measured byseveral authors2,3,4), the purpose of the present study was toresolve the big discrepancies of the different results and toextend the energy range of the measurements (see Figs. 1and 2). The preliminary results are shown in Fig.1 for theenriched targets and in Fig. 2 for natural cadmium, both forthe medically important 117mSn radioisotope. On Fig. 1 ourresults are much higher than the others under 30 MeV, thatis why we have measured the spectra in the December

experiment much longer, in order to separate thecontribution from other isotopes. At list one of the previous
results on natural cadmium is obviously wrong (Fig. 2), so
our contribution may give the correct results, as the it isconfirmed by the shape and amplitude of the TENDL
prediction.

Figure1. Preliminary resultof crosssections

forthe116Cd(D,3n)117mSn reaction

Figure 2. Preliminary result
natCd(D,3n)117mSn reaction

References

1)
2)
3)
4)

Institute for Nuclear Research, Hungarian Academy of Sciences
RIKEN Nishina Center᧦3 Faculty of Science, Hokkaido University
᧦4 Graduate School of Science, Hokkaido University
᧦15)

᧦26)

- 246 -of cross sections

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