Sensor for the detection of the incident point of an electron beam

Abstract

A novel sensor to detect the position of incidence of an electron beam on a target has been introduced where the X-rays starting from the point of incidence are detected by a position sensitive photodiode which is connected to an analyzing circuit. As part of an automatic control system the sensor allows the accurate guidance of the electron beam in vaporization and melting plants. To meet the high requirements in sensitivity, dynamics and position resolution, a special electronic circuit arrangement was developed to generate a signal that depends only on the position and not on the intensity of the incident radiation. The relative position resolution achieved with the described system is 1:1000. The admissible maximum frequency for the deflection of the electron beam is 20 Hz-2 kHz, dependent on the radiant intensity. The tensor can be used with all electron beam sources for acceleration voltages of at least 6 kV and a beam power exceeding 1 kW.