An improved charged particle detector

Claim 1

In a time-of-flight particle detector system including a first particle detector, a second particle detector spaced a known distance from said first detector, and means for measuring the time-of-flight of particles between said detectors, the improvement characterized in that said first particle detector is so constructed as to provide time pulses which are clearly distinguishable from background noise even in the presence of high radiation fields, said first detector comprising an enclosure, two Lucite light pipes mounted within said enclosure, an ultrathin plastic scintillator film sandwiched between said light pipes, said film having a thickness of a selected value in the range from 10 Mu g/cm.2 to 2 mg./cm.2, a third Lucite light pipe enclosing one end of said enclosure, a photomultiplier tube coupled to said third light pipe, said thin scintillator film being positioned perpendicular to the face of said photomultiplier tube, said enclosure comprising a highly polished metal reflector, said reflector and two Lucite light pipes being provided respectively with diametrically opposed and aligned openings and aligned holes having a common axis perpendicular to said thin film and for passage of particles from an external source of radiation through said thin scintillator film with a minimum of energy loss, and said first detector being adapted to be mounted within an evacuated chamber, whereby said particles passing through said scintillator film trigger light flashes for detection by said photomultiplier tube which in turn provides timing pulses for said detector system.