Spin concentration in a possible ESR dosimeter: An electron spin echo study on X-irradiated ammonium tartrate.
Spin concentration in a possible ESR dosimeter: An electron spin echo study on X-irradiated ammonium tartrate.
复制标题
可能的 ESR 剂量计中的自旋浓度：X 辐照酒石酸铵的电子自旋回波研究。
DOI：
10.1006/jmre.1998.1671
复制
发表时间：
1999
影响因子：
2.2
通讯作者：
A. Lund
中科院分区：
文献类型：
--
作者：
M. Brustolon;A. Zoleo;A. Lund
酒石酸铵的几个单晶和粉末样品，最近提出作为一个可能的ESR剂量计，已被X射线辐照不同剂量。总自由基浓度已确定定量cw ESR，通过与标准比较。用电子自旋回波谱对样品进行了研究。对于不同的脉冲微波功率值和不同的脉冲长度，已经获得了双脉冲回波衰减，并通过单指数函数进行了模拟。相位记忆时间TM对微波功率的依赖性已被利用，以获得瞬时扩散对自旋退相的贡献的信息。在室温下，自由基浓度在10（18）-10（19）spins/cm ~ 3范围内，瞬时扩散是主要的自旋退相机制。瞬时扩散与自由基总浓度的线性关系与理论一致。从后一个结果，我们得出结论，平均根-根距离对应于矩阵中的自由基的随机分布。本文介绍了一种用辐射酒石酸铵粉末样品的ESE衰变测量自由基浓度的简单方法。
Several single crystals and powder samples of ammonium tartrate, recently proposed as a possible ESR dosimeter, have been X-irradiated with different doses. The total radical concentration has been determined by quantitative cw ESR, by comparison with a standard. The samples have been studied by electron spin echo spectroscopy. The two-pulse echo decay has been obtained and simulated by a single exponential function for different values of the microwave power of the pulses and for different pulse lengths. The dependence of the phase memory time TM on the microwave power has been exploited to get information on the contribution of the instantaneous diffusion to spin dephasing. At room temperature in the range of radical concentrations of 10(18)-10(19) spins/cm3 the instantaneous diffusion is the dominant spin dephasing mechanism. The linear dependence of the instantaneous diffusion on the total concentration of the radicals is in agreement with the theory. From the latter result we conclude that the average radical-radical distance corresponds to a random distribution of the radicals in the matrix. A simple method of measuring the radical concentration by the ESE decays in powder samples of irradiated ammonium tartrate is described.