Patent ID: 9460886
Filing Date: 2016-10-04
CPC Classification: G01N,H01J

Claim Text:
1. An electron-bombarded detector for detecting low light signals, said electron-bombarded detector comprising: a vacuum tube structure defining a cylindrical vacuum tube chamber having a first end and an opposing second end; a photocathode disposed at said first end of the vacuum tube chamber and including a material that emits photoelectrons in response to said low light signals; a sensor disposed at the second end of the vacuum tube chamber and configured to receive at least some of said emitted photoelectrons, and to generate an electric signal in response to said received photoelectrons; a plurality of ring electrodes disposed in the vacuum tube chamber, each said ring electrode configured to generate, in response to an applied voltage, an electric field that accelerates said emitted photoelectrons toward said second end of the vacuum tight chamber; a magnetic field generator disposed adjacent to the vacuum tube structure and configured to generate a symmetric magnetic field in the vacuum tight chamber such that said symmetric magnetic field applies a focusing lens effect on said accelerated photoelectrons; and a controller configured to transmit said applied voltages to said plurality of ring electrodes such that the applied voltages on the electrodes around the photocathode are adjusted to compensate the electron optics aberrations, wherein said electron-bombarded detector is configured such that said photoelectrons received by said sensor have a landing energy below 2 keV.