Radiant energy – Invisible radiant energy responsive electric signalling – With or including a luminophor
Patent
1997-02-21
1999-03-09
Westin, Edward P.
Radiant energy
Invisible radiant energy responsive electric signalling
With or including a luminophor
25037006, 25039011, G01N 120
Patent
active
058804692
ABSTRACT:
Apparatus and method for discriminating against neutrons coming from directions other than a preferred direction and discriminating against gamma rays. Two photomultiplier (PM) tubes 9,10 are parallel to each other and are attached to one end of a light pipe 12. A neutron scintillator 13 is attached to the other end of the light pipe. The scintillator 13 is comprised of optical fibers arranged contiguously along a first direction, which is perpendicular to a length dimension of the optical fibers, and which optical fibers alternate between optical fibers which emit photons only in the lower portion of the electromagnetic spectrum and optical fibers which emit photons only in the higher portion of the electromagnetic spectrum. Typically, the optical fibers are about 100-250 microns. Filters 7,8 are between the PM tubes and the light pipe. One filter 7 transmits only photons in the lower end of the electromagnetic spectrum and the other filter 8 transmits only photons in the higher portion of the electromagnetic spectrum. Neutrons proceeding from a source which is parallel to the first direction will tend to cause only one optical fiber to emit photons. If neutrons enter the scintillator perpendicular to such first direction, photons will most likely be emitted by more than one optical fiber. A signal processing unit 11 will register a detected neutron if a signal is received from only one PM tube and will register a background event if signals are received from both PM tubes. If a gamma ray enters the detector and is detected, the scattered Compton electron most likely will cross two or more optical fibers, causing signals in both PM tubes. A signal processing unit 11 will register the event as a background event.
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Hanig Richard
Westin Edward P.
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