ODDZIAŁYWANIA NADSUBTELNE W CERAMICE (BiFeO3)0.9-(BaTiO3)0.1 WYTWORZONEJ PRZEZ AKTYWACJĘ MECHANICZNĄ

In this work the results of structural and magnetic investigations for (BiFeO3)0.9-(BaTiO3)0.1 ceramics prepared by mechanical activation are presented. The structural analysis and hyperfine interactions investigations were performed by X-ray diffraction and Mössbauer spectroscopy.W pracy przedstawiono wyniki badań strukturalnych i magnetycznych dla ceramiki (BiFeO3)0.9-(BaTiO3)0.1 otrzymanej w procesie aktywacji mechanicznej. Badania struktury i oddziaływań nadsubtelnych przeprowadzono odpowiednio metodami dyfrakcji promieniowania X oraz spektroskopii efektu Mössbauera

Verification of electron beam parameters in an intraoperative linear accelerator using dosimetric and radiobiological response methods

Background: The availability of linear accelerators (linac) for research purposes is often limited and therefore alternative radiation sources are needed to conduct radiobiological research. The National Centre for Radiation Research in Poland recently developed an intraoperative mobile linac that enables electron irradiation at energies ranging from 4 to 12 MeV and dose rates of 5 or 10 Gy/min. The present study was conducted to evaluate the electron beam parameters of this intraoperative linac and to verify the set-up to evaluate out-of-field doses in a water phantom, which were determined through dosimetric and biological response measurements. Materials and methods: The distribution of radiation doses along and across the radiation beam were measured in a water phantom using a semiconductor detector and absolute doses using an ionisation chamber. Two luminal breast cancer cell lines (T-47D and HER2 positive SK-BR-3) were placed in the phantom to study radiation response at doses ranging from 2 to 10 Gy.  Cell response was measured by clonogenic assays. Results and Conclusion: The electron beam properties, including depth doses and profiles, were within expected range for the stated energies. These results confirm the viability of this device and set-up as a source of megavoltage electrons to evaluate the radiobiological response of tumour cells

Effect of BaTiO3 concentration on structural and magnetic properties of mechanically activated BiFeO3-BaTiO3 system

In this research, the mechanical activation method is proposed as an alternative process of preparation of the (BiFeO3)1-x-(BaTiO3)x solid solutions with various concentrations of barium titanate (x = 0.1÷0.9). However, mechanical milling itself does not allow obtaining the desired products and additional thermal treatment is needed to complete the solid-state reaction. In the present studies, X-ray diffraction and 57Fe Mössbauer spectroscopy were applied as complementary methods in order to study the structural and magnetic properties of materials. The investigations revealed that an increase of BaTiO3 concentration causes changes in the crystalline and hyperfine magnetic structure of the studied (BiFeO3)1-x-(BaTiO3)x system

Structure and Mössbauer spectroscopy studies of mechanically activated (BiFeO3)1−x-(BaTiO3)x solid solutions

(BiFeO3)1-x-(BaTiO3)x solid solutions with x = 0.1–0.4 and 0.7 were investigated. The ceramics were prepared by mechanical activation technology and subsequent heat treatment. As was proved by X-ray diffraction, increase of BaTiO3 concentration causes a change in the crystalline structure from the rhombohedral structure characteristic of BiFeO3 to a cubic one. 57Fe Mössbauer spectroscopy allowed observation of a gradual transformation from an ordered spin structure of Fe3+ ions to the paramagnetic state with an increase of x