Low energy electron magnetometer using a monoenergetic electron beam

US4414509A · kind A · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• Jag J. Singh · Yorktown, US
• George M. Wood · Blossom, US
• Grayson H. Rayborn · Hattiesburg, US
• Frederick A. White, JR. · Schenectady, US

Key dates

• Filing date: Nov 26, 1980
• Grant date: Nov 8, 1983
• Expiry date: Nov 26, 2000

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R33/0213
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A low energy electron beam magnetometer that utilizes near-monoenergetic electrons thereby reducing errors due to electron energy spread and electron nonuniform angular distribution. In a first embodiment of the invention (FIGS. 3 and 4) atoms in an atomic beam 30 of an inert gas are excited to a Rydberg state (lasers 32, 33 and 34) and then electrons of near zero energy are detached from the Rydberg atoms (gas chamber 35 ). The near zero energy electrons are then accelerated by an electric field V.sub.acc to form the electron beam 21. In a second embodiment of the invention (FIG. 5) a filament 42 emits electrons into an electrostatic analyzer 40 which selects electrons at a predetermined energy level within a very narrow range. These selected electrons make up the electron beam that is subjected to the magnetic field being measured.