Speakers
Mr
Bogdan WĄs
(The Henryk Niewodniczański Institute of Nuclear Physics Polish Academy of Sciences, Cracow, Poland)Dr
Ryszard Misiak
(The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Cracow, Poland)
Description
Among neutron deficient Tc isotopes, 95mTc is a useful radiotracer due to a relatively long half-life (t1/2=61 d), and high abundance of its gamma-rays. It can be used for studying of a behavior of 99Tc in the environment and waste disposal, as well as in the development of new radiopharmaceuticals of 94m, 99mTc. Radioisotope 95mTc can be obtained by a bombardment of Mo-enriched and Nb targets with protons or alpha particles[1].
In the present work 95mTc was obtained by proton irradiation of natRu targets. Ru or RuCl3 powder with a natural isotopic composition was irradiated. The irradiation condition was 20 nA as proton of energy 60 MeV for 2-3 h at the Cracow AIC-144 cyclotron.
At first stage an investigation of volatilization of Tc, Rh and Ru as oxides by heating the target material – RuCl3 powder in an O2 stream was carried out. At second stage, the investigation with Ru powder as target material was done in the same experimental conditions as for studies of RuCl3 as target. The similar thermochromatograms were obtained for carrier-free Rh and macroscopic amount of Ru. One oxide of Rh was detected. Thermochromatogram of macroscopic amounts of Ru oxides showed wide peak in temperature range from 1340K to 300K. This peak corresponds to the oxides: RuO2 and RuO3[2-4]. Two peaks of carrier-free Tc have been observed at 620 K and 320 K for RuCl3 target and one peak at 850 K with right-sided tail for Ru target. Thermochromatograms characteristics of Tc i Ru indicate a continuous migration of Ru and Tc oxides into lower temperature[2-4]. In the case of RuCl3 target, the additional formation of volatile Tc and Ru oxychlorides can not be excluded. Taking into account obtained results for isolation Tc from RuCl3 target, high-temperature part of temperature gradient was extended. Tc carrier-free radionuclides were trapped in scrubber with 6 Mol/l HCl. In these experimental conditions about 1% of total amount of Ru was catched in scrubber, too.
The performed studies made it possible to obtain the following conditions for the separation Tc process: mass of RuCl3 target about 35 mg, starting temperature 1373 K, exposure time 100 minutes, O2 flow rate 60 cm3/min. In all experiments one peak of Rh was detected, probably as RhO2, at this same adsorption temperature independently of gradient temperature, exposure time and irradiated target material Ru or RuCl3 powder. The stable position of Rh peak during experiment indicates the possibility of separation Rh from target material. Further investigation is planned.
Acknowledgement: The work was done within framework of Polish Governmental Strategic Project: Supporting technologies for the development of safe nuclear power, Action 4: Development of techniques and technologies supporting management of spent nuclear fuel and radioactive waste (No SP/J/4/143321/11).
1. M. Izumo, H. Matsuoka, T. Sowita, Y. Nagame, T. Sekine, K. Hata, S. Baba „ Production of 95mTc with Proton Bombardment of 95Mo” Applied Radiation and Isotopes 42 (1991) 297
2. A. Steffen, K. Bachmann, "Gas chromatographic study of volatile oxides and hydroxides of Re, Tc, Os, Ru and Ir - I Investigation by isothermal gas chromatography", Talanta, 25, 1978, 551
3. A. Steffen, K. Bachmann, "Gas chromatographic study of volatile oxides and hydroxides of Re, Tc, Os, Ru and Ir - II Thermochromatographic investigations", Talanta, 25, 1978, 677
4. B. Eichler, F. Zude, W. Fan, N. Trautman, G. Herrmann, "Volatilization and deposition of ruthenium oxides in a temperature gradient tube", Radiochimica Acta, 56, 1992, 133
Primary author
Dr
Ryszard Misiak
(The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Cracow, Poland)
Co-authors
Mr
Bogdan WĄs
(The Henryk Niewodniczański Institute of Nuclear Physics Polish Academy of Sciences, Cracow, Poland)
Mr
Mirosław Bartyzel
(The Henryk Niewodniczański Institute of Nuclear Physics Polish Academy of Sciences, Cracow, Poland)
