Electron gun device for generating high-brightness femtosecond electronic pulse

Abstract

The invention provides an electron gun device for generating a high-brightness femtosecond electronic impulse. The electron gun device comprises an incident window, a sealing component, a vacuum cavity, a photocathode, a grid, an anode, an observation window, a molecular pump, a pre-stage dry pump, an electronic focusing magnetic lens, an RF (Radio Frequency) electronic compression cavity, an RF signal generating device, an x-direction electronic deflector, a y-direction electronic deflector and an electronic scanning plate. Through the invention, the broadening function of the space charge effect on longitudinal pulse duration of an electronic beam impulse is effectively suppressed; the problem that the divergence of the electronic beam is increased due to electric field distortion at a small hole of the anode is solved; and the horizontal and longitudinal electronic impulses have super-high resolution factors, and the real-time detection on super-high time resolution and space resolution of ultrafast processes such as molecular reaction dynamics can be performed.

Description

Technical field [0001] The invention relates to the research field of ultrafast electron beam dynamics, and in particular to an electron gun device for generating high-brightness femtosecond electron pulses. Background technique [0002] Since the 1980s, the birth of femtosecond lasers has made ultrafast molecular reaction dynamics a research hotspot. At first, the exploration of these ultrafast processes mostly used all-optical methods such as time-resolved reflection / transmission spectroscopy or Raman spectroscopy. Although these methods can detect the information of atomic and molecular structure changes, the relationship between spectra and atomic and molecular structure information has not yet been fully explained, which undoubtedly increases the analysis of structural changes in transient rapid reaction dynamics. Difficulty. In addition, affected by the optical properties of materials, the scope of application of these methods has great limitations. X-ray diffraction and ...

AI Technical Summary

Problems solved by technology

This is undoubtedly a waste of time, and it is not applicable to some non-reversible processes, which urgently requires the electronic pulse not only to meet the requirements in the time domain, but also to have sufficient brightness to obtain a diffraction image that can be analyzed

[0004] In the prior art, during the flight of the electron beam, the existence of the space charge effect makes the divergence of the electron beam gradually increase, causing it to spread in three-dimensional space, which seriously affects the pulse width of the electron beam in the horizontal and vertical directions.

In traditional devices, the space charge effect is suppressed by reducing the number of electrons per pulse, which is easy to cause blurred images and waste of time, which is an obstacle to the study of ultrafast physical chemistry and biological processes.

Images