公开(公告)号：US5308971A

公开(公告)日：1994-05-03

申请号：US8478

申请日：1993-01-25

Applicant: Martin Pope ,  Alexandre Dourandin

Inventor： Martin Pope ,  Alexandre Dourandin

IPC: G01J11/00 ,  G04F13/02 ,  H01J40/14

CPC classification number: G01J11/00 ,  G04F13/02

Abstract: Method and apparatus for measuring the time of short events, such as characteristics of a source of short radiation pulses or lifetime of excited states of a sample. The method and apparatus is based on a multi-step photoemission process from an active element target exhibiting superlinear photoemission. A short prompt radiation pulse is used to raise electrons to an excited state, and a following overlapping short probe pulse is used to raise the excited electrons to the vacuum level where they leave the sample, changing its charge state. The number of escaped electrons is measured as a function of the time delay between the prompt and probe pulses to provide the sought after information. Preferably, the charged target is suspended or supported in an electric field, and the voltage needed to restore the charge-changed target to its original position is used.

Abstract translation: 用于测量短时间的时间的方法和装置，例如短辐射脉冲源的特征或样品的激发态的寿命。 该方法和装置基于表现出超级线性光电子发射的活性元素靶的多步光电子发射过程。 使用短暂的辐射脉冲将电子提升到激发态，并且使用以下重叠的短探针脉冲将激发的电子升高到它们离开样品的真空水平，从而改变其电荷状态。 测量逃逸电子的数量作为提示和探测脉冲之间的时间延迟的函数，以提供所追求的信息。 优选地，充电目标被悬挂或支撑在电场中，并且使用将电荷改变的目标恢复到其原始位置所需的电压。