论文部分内容阅读
正电子湮没辐射角关联技术是正电子湮没谱学的基本手段之一。湮没辐射角关联曲线的测定能提供有关电子动量密度和费米面等方面的信息,并应用在金属、合金和固体材料等的研究中。本装置是测量2γ湮没辐射的一维快-慢符合角关联装置,它由一个扇形测量台和一个可移动的平台组成,总长约为4m。可动探头与样品装在测量台上,固定探头装在可移动的平台上,探头表面与样品之间的距离为1.5m,并可根据工作需要和辐射源强度的变化作适当的改变。转动手轮可驱动可动探头绕着样品的中心轴转动,转动的角度由测量台上的标尺读出。可动探头中心的角扫描范围为±30毫孤度。辐射源为10mCi的Na~(22),由专用架定位。辐射源和探头均用铅屏蔽。样品由样品架定位,其角度可作微小的调整。样品中产生的湮没辐射经过主、次两个准直器后由探头吸收测量。准直器的形状(圆孔或长缝)和大小(1—4mm)可以更换。典型的几何角分辨为0.66毫弧度。装置的对中由激光校准,水平由水准仪校准,移动平行度由加工精度保证。整个装置拆装和移动均比较方便。
Positron annihilation radiation angle correlation technique is one of the basic means of positron annihilation spectroscopy. The determination of the correlation curve of annihilation radiation angle can provide information on electron momentum density and Fermi surface, and is used in the research of metals, alloys and solid materials. The device is a one-dimensional fast-slow coincidence angle measuring device for measuring 2γ annihilation radiation. It consists of a sector measuring platform and a movable platform with a total length of about 4m. The movable probe and the sample are mounted on the measuring platform. The fixed probe is mounted on a movable platform. The distance between the probe surface and the sample is 1.5m. The distance between the probe and the sample can be changed according to the work requirement and the intensity of the radiation source. Turn the hand wheel to drive the movable probe around the center axis of the sample. The angle of rotation is read by the scale on the measuring platform. The angular range of the movable probe center is ± 30 mV. The radiation source is Na ~ (22) of 10mCi, positioned by a dedicated rack. Lead sources and probes are shielded with lead. Sample positioning by the sample holder, the angle can make minor adjustments. The annihilation radiation generated in the sample is absorbed by the probe after being measured by the primary and secondary collimators. Collimator shape (round hole or long seam) and size (1-4mm) can be replaced. The typical geometric angle resolution is 0.66 milliradians. The alignment of the device is calibrated by a laser, the level is calibrated by a level gauge and the parallelism of movement is guaranteed by the machining accuracy. The whole device dismantling and moving are more convenient.