US 5,019,711 AGranted

Scanning-liquid ionization chamber imager/dosimeter for megavoltage photons

AssigneeThe Regents of the University of Michigan

InventorLarry E. Antonuk

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Abstract

A scanning, liquid ionization chamber IMAGER/DOSIMETER having a rectangular housing with a top of a thin predetermined thickness. An internal frame lies inside the rectangular housing and is welded thereto. Two planes of orthogonal wires are strung across the internal frame and immobilized thereby. These wires are electrically insulated from the rectangular housing and internal frame by non-conductive connectors. A first plane of wires serves a sensing function while the other plane of wires has a bias applied thereto one wire at a time. The rectangular housing is sealed after a liquid ionization medium completely fills any open space contained inside the rectangular housing. Non-conductive feed through wiring means are connected to the planes of wires. The first and second planes of wires are suspended in free space inside the rectangular housing. The liquid ionization medium is of a purity so as to extend electron lifetime; thus when a radiation beam causes electrons in the ionization medium these free electrons are swept away by the electric field of the applied bias and are output as a detected signal.

Claims11

Dependent claims

A scanning liquid ionization chamber for use with a radiation beam, comprising:

a closed housing;
a first plurality of substantially parallel wires arranged in a first plane;
a second plurality of substantially parallel wires arranged in a second plane, wherein the second plane of said second plurality of substantially parallel wires is spaced a predetermined distance from the first plane of said first plurality of substantially parallel wires, and said second plurality of wires are arranged in a direction orthogonal to the direction in which said first plurality of wires are arranged;
means for stringing and immobilizing said first plurality and said second plurality of wires, said means for stringing and immobilizing being connected to said closed housing and electrically insulating said first plurality of wires and said second plurality of wires from said closed housing;
a liquid ionization medium having a predetermined purity located inside said closed housing;
biasing means for applying a biasing voltage to at least one wire of said second plurality of wires, said radiation beam producing electrons in said ionization medium, and said biasing means in combination with said radiation beam producing a detection signal based at least in part on said electrons along at least one wire of said first plurality of wires;
and
output means connected to said first plurality of wires for extracting said detection signal.

5 more elements

A scanning liquid ionization chamber for use with a radiation beam, comprising:

a closed housing;
an internal frame mounted inside said housing;
a first side of said internal frame having a predetermined plurality of holes in planar alignment with a predetermined plurality of holes located on a side of said internal frame opposite to said first side;
a second side of said internal frame having a predetermined plurality of holes in planar alignment with a predetermined plurality of holes located on a side of said internal frame opposite to said second side;
a first plurality of wires extending through said holes in said first side and said holes opposite to said first side;
a second plurality of wires extending through said holes in said second side and said holes opposite to said second side, said first and second plurality of wires forming orthogonal planes separated by a predetermined distance;
means for stringing and immobilizing said first and second plurality of wires through said holes in said first side and said side opposite said first side and said holes in said second side and said side opposite said second side;
non-conductive wire feed through means for sealing a plurality of holes located on said housing;
a liquid ionization medium located inside said closed housing;
biasing means for applying a biasing voltage to at least one wire of said second plurality of wires, said radiation beam producing electrons in said ionization medium, and said biasing means in combination with said radiation beam producing a detection signal based at least in part on said electrons along at least one wire of said first plurality of wires;
and
output means connected to said first plurality of wires for extracting said detection signal.

9 more elements

Dependencies are inferred from the claim text.