RIKEN Accel. Prog. Rep. 48 (2015)

Ⅲ-3. Radiochemistry & Nuclear Chemistry

Improvement in the chemical yield of purified 109Cd for fee-based distribution
at the RIKEN AVF cyclotron
Y. Wakitani,＊1 S.Yano,＊1 T.Yamada,＊1 H. Haba,＊2 S. Shibata,＊2 and K. Takahashi＊2Since October 2007, we have distributed fee-based 109Cd（T1/2 = 469.4d）,produced via the 109Ag(d,2n)109Cd reaction
using the RIKEN AVF cyclotron, to the general public.1)
After irradiation, 109Cd was chemically separated from theAg target and reaction byproducts. We have employed aseparation method involving AgCl precipitate and anion
exchange in HCl.2) However, a considerable percentage ofthe produced 109Cd tends to be lost by inclusion andadsorption on the AgCl precipitate in this method. F. W. E.
Strelow3) and M. K. Das4) applied another technique usinghydrobromic acid (HBr) for 109Cd separation. Betterchemical yield could be expected because the precipitation
step was not required in this method. In order to improvethe chemical yield for 109Cd separation, we studied a similar
technique using anion exchange in HBr without AgCl
precipitation for the chemical separation of 109Cd from theirradiated target in the present work.
Cadmium-109 was produced by irradiating a silver plate innatural isotopic abundance (chemical purity: >99.99%; size:
ø15 mm; thickness: 0.6 mm) using a 24-MeV deuteronbeam from the RIKEN AVF cyclotron. The irradiation timewas 37 h, and the average beam intensity was 9 µA. During
the irradiation, the target was continuously cooled withhelium gas and water.
Ag(1.1g)c.HNO3: 5mL ＋ H2O: 5mL＋ H2O2 × 3drops
heat to dryness

After the irradiation, 109Cd was chemically separated fromthe Ag target according to the procedure shown in Fig. 1.
The Ag target was dissolved in 5 mL of concentrated
nitric acid, 5 mL of water, and three drops of hydrogen
peroxide solution. The solution was evaporated to dryness.
The residue was dissolved in 10mL of c. HBr. This solution
was also evaporated to dryness. The residue was dissolvedin 90 mL of 7 M HBr. This 7 M HBr solution was passed
through the anion-exchange column (ø7 mm × 40 mmheight) packed with Dowex 1X8 (100–200 mesh, Cl– form).
109
Cd was adsorbed on the resin, and Ag was eluted. Thenthe column was washed with 7 M HBr and 0.02 M HCl.
109
Cd was adsorbed on the resin and the unwanted 65Zn waseluted. Finally, 109Cd was eluted with 3 M HNO3 and H2O.
The present results are shown in Table 1,together withthose obtained in our previous study. The specificradioactivity and radionuclide purity were measured by
-ray spectrometry using a Ge detector. The chemicalimpurity was also estimated by ICP-MS for a control
sample treated using the same chemical process as theirradiated Ag target. Chemical impurities were found to be57 ppm for S and 87 ppm for Ca. The others were below 10ppm. As shown in Table 1, the chemical yield obtained in
the present work was significantly improved from 80% to98%.
Table1. Comparison of the results of the 109Cd purification
between our previous2) and the present work.
Our previous

Thisworkwork

80989493

Decontamination factor of Ag

3×106

7.6×106

Radionuclidic purity>99.9%>99.9%

c.HBr: 10mL
heat to dryness
7M HBr: 90mL

Chemical yield (%)
Specific radioactivity*1

7M HBr: 10mL × 4(MBq/μg)

0.02M HCl: 5mL × 6
3M HNO3: 2mL × 3
H2O: 5mL
Dowex 1×8 , 100-200 mesh,
φ7.0mm× 40mm height

Ag65

Zn

109

CdFig. 1. Chemical separation scheme for 109Cd.

*1 (Beam intensity :10 μA, irradiation time: 48 h)
References

1) T. Kambara et al.: RIKEN Accel. Prog. Rep. 42, 295 (2008).
2) J. Kanaya et al.: RIKEN Accel. Prog. Rep. 45, 203 (2012).
3) F. W. E. Strelow et al.: Anal. Chem. 40, 2021 (1968).
4) M. K. Das et al.: The Third International Conference on
Application of RadiotraCers and Energetic Beams in Sciences(ARCEBS-14), January, 2014, Kolkata, India.

＊1
Japan Radioisotope Association＊2

RIKEN Nishina Center- 298 -

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