Beam intensity monitor for a high energy particle beam system

A beam intensity monitor for monitoring high energy particle beams by placing the monitor across the path of a particle beam to intercept a small portion of the particle beam as it passes therethrough. The monitor comprises primarily a four resistor bridge arrangement driven by a power source and utilizing a voltmeter as a detector for changes in bridge voltage. One of the four resistors functions as the sensor for the monitor. The sensor comprises an elongated wire resistance that is folded, coiled or otherwise shaped to encompass an area or region through which the neutral particle beam is directed to pass. The resistance wire is heated by passage of the particle beam therethrough, being impacted by approximately 0.1% of the beam, causing the bridge to become unbalanced. The magnitude of the voltage produced is proportional to the power in the beam. Simultaneously, phosphor beads attached to the elongated wire are also struck by the particles in the beam. These particles cause the phosphor to fluoresce and the light which is emitted from the phosphors is observed by a television camera, providing a measure of the spatial distribution of the particles within the beam.