Preparation of metallic target of 100Mo for production of 99mTc in cyclotron

• Main Authors: Janiak, T., Cieszykowska, I., Barcikowski, T., Jerzyk, K., Mielcarski, M.
• Other Authors: National Centre for Nuclear Research, Poland, Radioisotope Centre POLATOM
• Format: Others
• Language: English
• Published: Helmholtz-Zentrum Dresden - Rossendorf 2015
• Subjects: 99mTc; 100Mo; Zyklotron; cyclotron; ddc:530
• Online Access: http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-164572; http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-164572; http://www.qucosa.de/fileadmin/data/qucosa/documents/16457/13%20WTTC15%20-%20Mo_pellets%20T_Janiak-kw.pdf

Introduction Technetium-99m, the daughter of 99Mo is the most commonly used radioisotope in nuclear medicine [1–2]. Current global crisis of 99Mo supply, aging of nuclear reactors and staggering costs force the search for alternative sources of 99mTc. Radioisotope Centre POLATOM joined the IAEA Coordinated Research Project on “Accelerator-based Alternatives to Non-HEU Production of 99Mo/99mTc”. The planned outcome of this project is development of 99mTc production method using the reaction of 100Mo(p,2n)99mTc [3] in Polish cyclotron. This work presents the results concerning preparation of 100Mo target for irradiation with protons. Material and Methods The manufacturing of Mo target was performed using pressing of molybdenum powder into pellets and its sintering in hydrogen atmosphere at 1600 oC [4]. For this purpose a tantalum and stainless steel plates were used as support. Several pellets using molybdenum powder with particles size of 2 µm in diameter were pressed at different values of pressure. Results and Conclusion The optimized parameters of pressing molyb-denum pellets with various sizes are given in TABLE 1. It was found that the pellets did not adhere neither to the tantalum nor stainless steel plates but they conducted electricity very well. Pellets prepared with higher pressure were more mechanically resistant, however application, even the highest used pressure did not ensure its satisfactory stability. In order to improve mechanical strength, pressed Mo pellets were sintered in hydrogen atmosphere at temperature of 1600 °C. As a result of this process dimensions of Mo pellets decreased: diameter by 13 %, thickness by 12 %, weight by 1.5 %, volume by 34 % while density increased by 50 %. The changes of these parameters are associated with reduction of molybdenum oxide and removal of oxygen from intermetallic space. It was confirmed by photos of microscopic cross section of pellets before and after sintering. It was observed, that after sintering Mo pellets got a metallic form with very high hardness and mechanical strength.