DOUBLE HELIX BORON-10 POWDER THERMAL NEUTRON DETECTOR

摘要

A double-helix Boron-10 powder detector having intrinsic thermal neutron detection efficiency comparable to 36″ long, 2-in diameter, 2-bar Helium-3 detectors, and which can be used to replace such detectors for use in portal monitoring, is described. An embodiment of the detector includes a metallic plate coated with Boron-10 powder for generating alpha and Lithium-7 particles responsive to neutrons impinging thereon supported by insulators affixed to at least two opposing edges; a grounded first wire wound in a helical manner around two opposing insulators; and a second wire having a smaller diameter than that of the first wire, wound in a helical manner around the same insulators and spaced apart from the first wire, the second wire being positively biased. A gas, disposed within a gas-tight container enclosing the plate, insulators and wires, and capable of stopping alpha and Lithium-7 particles and generating electrons produces a signal on the second wire which is detected and subsequently related to the number of neutrons impinging on the plate.

主权项

1. Apparatus for detecting thermal neutrons comprising: a first electrically non-conducting elongated bar having a first long side with a first channel formed along the length thereof, and a second long side opposite the first long side; a second electrically non-conducting bar spaced apart from said first bar having a first long side with a second channel formed along the length thereof opposing the first channel, and a second long side opposite the first long side; a flat metallic plate coated with Boron-10 powder on both sides thereof responsive to neutrons, for generating alpha and Lithium-7 particles, adapted to fit into the first channel and the second channel, forming a particle generation unit; a first electrically conducting wire having a first diameter helically wound between the second side of said first bar and the second side of said second bar; a second electrically conducting wire having a second diameter smaller than the first diameter, helically wound between the second side of said first bar and the second side of said second bar in a non-intersecting manner with said first wire, forming a first particle detection unit; a gas-tight, electrically conducting chamber surrounding said particle detection unit; a gas disposed within said chamber effective for stopping alpha and Lithium-7 particles and for generating electrons and ions; a high-voltage power supply for electrically positively biasing said second wire, said first wire being electrically grounded to said chamber; and means for receiving and processing an electrical signal from said second wire.