Boston University

Massachusetts Institute of Technology

Brandeis University

Steven P Ahlen

Andrew Inglis

Peter H Fisher

Hermann Wellenstein

Denis Dujmic

Hidefumi Tomita

Thomas E Coan

A neutron detector includes a pressure vessel, an electrically conductive field cage assembly within the pressure vessel and an imaging subsystem. A pressurized gas mixture of CF,He andHe at respective partial pressures is used. The field cage establishes a relatively large drift region of low field strength, in which ionization electrons generated by neutron-He interactions are directed toward a substantially smaller amplification region of substantially higher field strength in which the ionization electrons undergo avalanche multiplication resulting in scintillation of the CFalong scintillation tracks. The imaging system generates two-dimensional images of the scintillation patterns and employs track-finding to identify tracks and deduce the rate and direction of incident neutrons. One or more photo-multiplier tubes record the time-profile of the scintillation tracks permitting the determination of the third coordinate.

Direction sensitive neutron detector

A thermal neutron detector includes a planar detector housing having two glass panels spaced apart by a gas-tight seal defining a detection chamber. Lithium foils adhered to inner surfaces of the glass panel emit alpha particles and tritons in response to incident thermal neutrons, and an inert detection gas is ionized to generate drift electrons. A planar array of detection wires is spaced from the lithium foils and extends outside the detection chamber. Electronic bias applies a field voltage between the wires and the lithium foils to establish a drift electric field to attract the drift electrons to the wires and provide a large electric field to cause electron multiplication. Detection circuitry detects electric signals in the wires generated by the drift of positive ions away from the wires and interprets the electrical signals as incidence of thermal neutrons on the detector.

Glass-panel lithium-6 neutron detector

An optical connection apparatus is provided for removably connecting an electro-optical device, particularly a phototube transducer, to a transparent light-conducting material. The apparatus includes a transparent optical coupling disc which is bonded to an entrance window of the transducer with a transparent epoxy. The coupling disc has a threaded stud extending from a side of the disc opposite to the side which is bonded to the transducer. A hole is formed in the transparent material and a threaded insert is secured therein. The threaded stud extending from the disc/transducer combination is then mated with the threads of the hole insert. A layer of optical grease is placed between the disc and the transparent material, and the assembly is screwed together until the disc is flush against the surface of the transparent material.

Apparatus for coupling an optical transducer to a light guide

Growing community of inventors

Brookline, MA, United States of America

Steven P Ahlen