Aubin-Chevaldonnet V, Gourier D, Caurant D, Esnouf S, Charpentier T, Costantini J M
CNRS, Ecole Nationale Supérieure de Chimie de Paris (ENSCP, ParisTech), Laboratoire de Chimie de la Matière Condensée de Paris, UMR-CNRS 7574, 11, rue P et M Curie, 75231 Paris Cedex 05, France.
J Phys Condens Matter. 2006 Apr 26;18(16):4007-27. doi: 10.1088/0953-8984/18/16/009. Epub 2006 Apr 7.
We have studied by electron paramagnetic resonance the mechanism of defect production by electron irradiation in barium hollandite, a material used for immobilization of radioactive caesium. The irradiation conditions were the closest possible to those occurring in Cs storage waste forms. Three paramagnetic defects were observed, independently of the irradiation conditions. A hole centre (H centre) is attributed to a superoxide ion O(2)(-) originating from hole trapping by interstitial oxygen produced by electron irradiation. An electron centre (E(1) centre) is attributed to a Ti(3+) ion adjacent to the resulting oxygen vacancy. Another electron centre (E(2) centre) is attributed to a Ti(3+) ion in a cation site adjacent to an extra Ba(2+) ion in a neighbouring tunnel, originating from barium displacement by elastic collisions. Comparison of the effects of external irradiations by electrons with the β-decay of Cs in storage waste forms is discussed. It is concluded that the latter would be dominated by E(1) and H centres rather than E(2) centres.
我们通过电子顺磁共振研究了钡硬锰矿中电子辐照产生缺陷的机制，钡硬锰矿是一种用于固定放射性铯的材料。辐照条件尽可能接近铯储存废料形式中出现的条件。无论辐照条件如何，均观察到三种顺磁缺陷。一个空穴中心（H中心）归因于超氧离子O₂⁻，它源自电子辐照产生的间隙氧捕获空穴。一个电子中心（E₁中心）归因于与产生的氧空位相邻的Ti³⁺离子。另一个电子中心（E₂中心）归因于阳离子位点中的Ti³⁺离子，该阳离子位点与相邻隧道中额外的Ba²⁺离子相邻，这是由弹性碰撞导致的钡位移产生的。文中讨论了电子外部辐照与储存废料形式中铯的β衰变的影响比较。得出的结论是，后者将由E₁和H中心主导，而不是E₂中心。
