Westinghouse Electric Corporation

Patrick E Felice

John Bartko

John G Seidel

Chang K Chu

Edward M Petrie

Krishan S Tarneja

Joseph L Gonzalez

Phillip D Blais

A method of lithographically forming a pattern on a surface is disclosed. The surface on which the pattern is to be formed is first coated with a resist layer. A mask preferably consisting of a beryllium of foil and a pattern gold layer affixed thereto is then positioned in overlying relationship to the resist layer. The thickness of the beryllium foil is selected such that it is transparent to high energy particles of a preselected energy while the combination of the pattern gold areas and the beryllium foil is impervious to these particles. A flood beam of high energy particles is directed such that it impinges on the beryllium foil thereby exposing the resist in areas not protected by the combination of the beryllium foil and the gold. The resist layer is processed to produce a patterned layer.

High resolution lithography using protons or alpha particles

The switching time of certain semiconductor devices is decreased while maintaining other electrical characteristics of the devices by irradiating them with a neutron radiation source of greater than 1.0 Mev. to a dosage between 1.times.10.sup.11 and 1.times.10.sup.15 neutrons per square centimeter. The irradiation is preferably to a dosage between 1.times.10.sup.1 and 1.times.10.sup.14 neutrons per square centimeter and preferably has substantial energy greater than 14 Mev. The devices are also annealed during and/or subsequent to the irradiation at a temperature higher than the highest specified temperature and preferably at least 50.degree. C. higher than the highest specified temperature.

Reducing the switching time of semiconductor devices by neutron

The finely-divided particles of a selected phosphor material are combined with an aqueous solution of a suitable binder material to form an emulsion which is spread uniformly on the smooth surface of a support member. The wet coating is then heated to remove the water and the resulting film is sintered to produce a strong, continuous film. The film is then peeled from the support member resulting in a uniformly thick sheet of phosphor and binder from which dosimeters can be cut or stamped to any desired size.

Technique for fabricating radiation sensitive dosimeters

The heating element in a conventional radiation dosimeter reading apparatus which functions to both physically support a dosimeter as well as heat the dosimeter to a temperature of luminescence, is modified to include a dished portion, or recessed portion, having a flat bottom and sufficient dimensions to receive the radiation dosimeter and allow for the positioning of a transparent retainer, i.e., a glass plate, in contact with the dosimeter to physically retain the dosimeter in the recess to avoid deformation of the dosimeter when heated, and transmit light emanating from the dosimeter when heated.

Heater design for reading radiation dosimeters

An improved thermoluminescent dosimeter system and apparatus for sensing alpha particle emission. A thermoluminescent body is sealed between a pair of metallized plastic films. The dosimeter is mounted within a protective inverted cup or a tube closed at one end, which is disposed in a test hole for exposure to radioactive radon gas which is indicative of uranium deposits.

Thermoluminescent dosimeter system

Underground uranium deposits are located by placing wires of dosimeters each about 5 to 18 mg/cm.sup.2 thick underground in a grid pattern. Each dosimeter contains a phosphor which is capable of storing the energy of alpha particles. In each pair one dosimeter is shielded from alpha particles with more than 18 mg/cm.sup.2 thick opaque material but not gamma and beta rays and the other dosimeter is shielded with less than 1 mg/cm.sup.2 thick opaque material to exclude dust. After a period underground the dosimeters are heated which releases the stored energy as light. The amount of light produced from the heavily shielded dosimeter is subtracted from the amount of light produced from the thinly shielded dosimeter to give an indication of the location and quantity of uranium underground.

Locating underground uranium deposits

The turn-off time of a reverse blocking diode thyristor is decreased without significantly effecting other electrical characteristics by irradiating with a radiation source to a dosage corresponding to between about 4 .times. 10.sup.13 and about 2 .times. 10.sup.14 electrons/cm.sup.2 and preferably to between about 6 .times. 10.sup.13 and about 2 .times. 10.sup.14 electrons/cm.sup.2 with 2 MeV electron radiation source. Preferably the radiation source is electron radiation with an energy greater than 1 MeV.

Irradiation for rapid turn-off reverse blocking diode thyristor

Underground uranium deposits are located by placing pairs of dosimeters each about 5 to 18 mg/cm.sup.2 thick underground in a grid pattern. Each dosimeter contains a phosphor which is capable of storing the energy of alpha particles. In each pair one dosimeter is shielded from alpha particles with more than 18 mg/cm.sup.2 thick opaque material but not gamma and beta rays and the other dosimeter is shielded with less than 1 mg/cm.sup.2 thick opaque material to exclude dust. After a period underground the dosimeters are heated which releases the stored energy as light. The amount of light produced from the heavily shielded dosimeter is subtracted from the amount of light produced from the thinly shielded dosimeter to give an indication of the location and quantity of uranium underground.

Growing community of inventors

Jeannette, PA, United States of America

Patrick E Felice