Abstract

Using the methods of positron annihilation and optical spectroscopy, the effect of gamma (Co⁶⁰) and electron irradiation (Cockcroft–Walton accelerator) on NaCl single crystals, followed by annealing at various temperatures. It was found that electron color centers are effective traps of positrons diffusing in the lattice. At the same time, hole centers do not capture positrons. It was shown that positrons are captured by sodium clusters formed in the bulk of NaCl crystals upon annealing (443 K) of irradiated (2650 Mrad) samples. The annihilation characteristics of captured positrons allow us to estimate size of sodium clusters R = 23.0 nm and their concentration N_x = 5.3 × 10¹⁷ cm^–3. Taking into account the fact that modern optical and positron spectrometers are quite compact and sensitive instruments, the monitoring of the processes of radiation degradation of the geological rock of rock salt can be carried out directly at the disposal sites of radioactive waste rather quickly and with the necessary degree of sensitivity to the accumulation of radiolytic products.

中文翻译：

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天然石盐单晶辐射降解过程中辐射缺陷和Na簇的控制

摘要

使用正电子an没和光谱学方法，对NaCl单晶进行伽玛（Co ⁶⁰）和电子辐照（Cockcroft-Walton促进剂）的影响，然后在不同温度下进行退火。发现电子色心是正电子在晶格中扩散的有效陷阱。同时，空穴中心不捕获正电子。结果表明，在对（2650 Mrad）样品进行退火（443 K）时，NaCl晶体中形成的钠簇会捕获正电子。捕获的正电子的an灭特性使我们能够估计钠团簇的大小R = 23.0 nm及其浓度N _x = 5.3×10 ¹⁷ cm ^–3。考虑到现代光学和正电子光谱仪是非常紧凑和灵敏的仪器，可以直接在放射性废料的处置场所进行岩盐地质岩石辐射降解过程的监测，而且速度非常快。对放射性分解产物积累的必要敏感性。