Ceeh Hubert, Weber Josef Andreas, Leitner Michael, Böni Peter, Hugenschmidt Christoph
Technische Universität München, Lehrstuhl E21, Garching, Germany.
Rev Sci Instrum. 2013 Apr;84(4):043905. doi: 10.1063/1.4801454.
Angular correlation of annihilation radiation (ACAR) is a well established technique for the investigation of the electronic structure. A major limitation of ACAR studies is the available positron flux at a small spot on the sample. For this reason, the focus of this work is put on the discussion of a newly developed source-sample stage of the new 2D-ACAR spectrometer at Technische Universität München which uses an optimized static magnetic field configuration to guide the positrons onto the sample. The achieved spot diameter is d(FWHM) = 5.4 mm, with a high efficiency over the whole energy spectrum of the (22)Na positron source. The implications of the performance of the source-sample stage are discussed with regard to 2D-ACAR measurements of single crystalline α-quartz, which serves as a model system for the determination of the total resolution. A value of (1.53 × 1.64) mrad(2) FWHM was achieved at room temperature.
湮没辐射角关联（ACAR）是一种用于研究电子结构的成熟技术。ACAR研究的一个主要限制是样品上小光斑处可用的正电子通量。因此，这项工作的重点是讨论慕尼黑工业大学新2D-ACAR光谱仪新开发的源-样品台，该源-样品台使用优化的静磁场配置将正电子引导到样品上。所实现的光斑直径为d（半高宽）=5.4毫米，在（22）Na正电子源的整个能谱上具有高效率。针对用作确定总分辨率的模型系统的单晶α-石英的2D-ACAR测量，讨论了源-样品台性能的影响。在室温下实现了（1.53×1.64）毫弧度（2）半高宽的值。
