Northern Telecom Limited

Varian Associates, Inc.

Derek J Day

Jingming Xu

Willi Fencl

Heinrich Riem

Reza Majidi-Ahy

Salvatore Provenzale

Mark A Sweeney

Rolf Staehelin

Rolf Stahelin

William A Hagley

Salvatore Provencale

The present invention provides electrode assemblies for LIC imagers that maximize ion collection and the electric field for the minimum bias voltage. To achieve this optimization the ion collection is confined to small regions. Due to this limited ion collection region, high neutralization efficiencies and fast sweep-out times can be obtained. Furthermore, with an electrode separation of approximately 0.1 millimeters, pulse voltages of less than 100 volts can be used. Low voltages result in improved reliability, longer system life, and lower safety risks.

Liquid ion chamber electrode apparatus

A three terminal ionization chamber includes a first electrode coupled to a bias voltage source spaced apart from a second electrode coupled to ground. A third terminal is provided which is positioned between the first and second electrodes. Measurement circuitry may be coupled to the third terminal to measure charge indicative of the amount of radiation incident to the chamber.

Three terminal ion chambers

A three terminal semiconductor device relies on resonant tunnelling through a quantum well resonator for its operation. The device has a first layer of a narrow bandgap semiconductor, a second layer of a narrow bandgap semiconductor, and a quantum well resonator between the first layer of a narrow bandgap semiconductor and the second layer of a narrow bandgap semiconductor. The quantum well resonator comprises a first layer of a wide bandgap semiconductor, a second layer of a wide bandgap semiconductor, and a third layer of a narrow bandgap semiconductor between the first layer of a wide bandgap semiconductor and the second layer of a wide bandgap semiconductor. All of the layers referred to above have a common conductivity polarity. The semiconductor device further comprises an electrical contact to the first layer of a narrow bandgap semicondcutor, an electrical contact to the second layer of a narrow bandgap semiconductor, and a terminal for applying a non-uniform electric field to the quantum well resonator to modulate resonant tunnelling characteristics of the quantum well resonator. The terminal for applying a non-uniform electric field to the quantum well resonator may comprise a field plate on the first layer of a narrow bandgap semiconductor, on the second layer of a narrow bandgap semiconductor. Alternatively, the terminal for applying a non-uniform electric field to the quantum well resonator may comprise a doped region extending into the third layer of a narrow bandgap semiconductor. The semiconductor device is useful in switching or logic applications, and in millimeter wave applications.

Three terminal semiconductor device

A logic gate comprises a bipolar switching transistor and a depletion mode field effect load device. A current independent voltage source and a voltage independent current source are connected in series between an input terminal of the logic gate and a base of the bipolar transistor. The voltage independent current source is a depletion mode field effect transistor having a source and drain which are connected in series with the current independent voltage source and the base of the bipolar transistor. A feedback device is connected in series between a gate of the current source field effect transistor and a gate of the load transistor. A discharge device is connected in parallel with the current independent voltage source for actively discharging a base-emitter junction of the bipolar transistor during switching of the bipolar transistor from an on state to an off state. The logic gate is particularly suitable for use in memory elements.

High speed noise immune bipolar logic family

Growing community of inventors

Los Gatos, CA, United States of America

Derek J Day