The space-charge effect, due to the instantaneous emission of many electrons after the absorption of a single photons pulse, causes distortion in the photoelectron energy spectrum. Two calculation methods have been applied to simulate the expansion during a free flight of clouds of mono- and bi-energetic electrons generated by a high energy pulse of light and their results have been compared. The accuracy of a widely used tool, such as SIMION(R), in predicting the energy distortion caused by the space-charge has been tested and the reliability of its results is verified. Finally we used SIMION(R) to take into account the space-charge effects in the simulation of simple photoemission experiments with a time-of-flight analyzer.
A quantitative comparison of time-of-flight momentum microscopes and hemispherical analyzers for time- and angle-resolved photoemission spectroscopy experiments
Detecting the full photoemission cone from laser-based ARPES experiments by leveraging deflector technology
Institut National de la Recherche Scientifique - Énergie Matériaux Télécommunications(国立科学研究研究所 - 能源材料电信);McGill University(麦吉尔大学);Max Planck Institute for Chemical Physics of Solids(马克斯·普朗克固体化学物理研究所);Brookhaven National Laboratory(布鲁克海文国家实验室)
Accurately accounting for effects on times-of-flight caused by finite field-transition times during the ejection of ions from a storage trap: A study for TOF and MRTOF mass spectrometry
Very Efficient Spin Polarization Analysis (VESPA): New Exchange Scattering-based Setup for Spin-resolved ARPES at APE-NFFA Beamline at Elettra
完整的光电子发射实验能够测量光电子终态的完整量子集,对于研究其性质由强电子和自旋相关决定的材料和纳米结构具有很高的需求。我们在这里报告的实施新的自旋极化仪VESPA(非常有效的自旋极化分析)在APE-NFFA光束线在Elettra是基于光电子自旋和铁磁表面之间的交换耦合在反射设置。该系统被设计为与专用的Scienta-Omicron DA 30电子能量分析仪集成,允许沿垂直轴进行两次同时反射测量,在两个目标的磁化切换之后,允许在高分辨率模式下操作DA 30的同时执行自旋极化的3D矢量重建。VESPA是位于的里雅斯特的Elettra同步加速器上的第一个自旋分辨ARPES(SPARPES)装置,自2015年秋季以来一直受到SPARPES用户的大力开发。
A novel method for the line-of-response and time-of-flight reconstruction in TOF-PET detectors based on a library of synchronized model signals
本文提出了一种新的闪烁体探测器命中时间和命中位置重建方法。该方法基于检测器信号与存储在针对闪烁点的一组明确定义的位置配准的同步模型信号库中的结果的比较。命中位置被重建为对应于来自库的与测量信号最相似的信号的命中位置。相互作用的时间被确定为所测量的信号与库中最相似的信号之间的相对时间。测量信号和模型信号的相似度被定义为在多维测量空间中表示测量信号和模型信号的点之间的距离。该方法的新颖性还在于所提出的模型信号同步的方式,使得能够直接确定从湮灭点到检测器的湮灭量子的飞行时间(TOF)之间的差异。使用通过J-PET探测器的双带原型和作为湮灭伽马量子源的$^{22}$ Na钠同位素获得的实验数据来验证所介绍的方法。探测器由尺寸为5 mm x 19 mm x 300 mm的塑料闪烁体带制成,在两侧光学连接到光电倍增管,利用所介绍的方法,建立了空间分辨率约为1.3 cm($σ$),飞行时间分辨率约为125 ps($σ$)的空间分辨率和飞行时间分辨率。
ToF-PAX-RIXS: A Time-of-Flight Spectrometer for combined ARPES and RIXS
Karlsruhe Institute of Technology(卡尔斯鲁厄理工学院);Johannes Gutenberg-Universität(约翰内斯·古腾堡大学);Deutsches Elektronen-Synchrotron DESY(德国电子同步加速器);Stockholm University(斯德哥尔摩大学);Christian-Albrechts-Universität zu Kiel(基尔大学)