Patent ID: 7489136
Filing Date: 2009-02-10
Classification: G01R

Abstract:
1. A device for detecting radiation, comprising: a sensor comprising N sensor elements configured to sense and output a signal in response to radiation emanating from an unknown source; a detector electrically connected to the sensor and configured to receive the response signal, wherein said detector is configured to detect the radiation based on a current level of the response signal; and a test circuit electrically connected to the sensor, wherein the test circuit is configured to output an electrical signal comprising a current pulse; and a reference circuit electrically connected to the test circuit, wherein a first portion of the electrical signal flows from the test circuit through the sensor to the detector, wherein a second portion the electrical signal flows from the test circuit to the reference circuit, wherein the test circuit is configured to test at least the sensor based on an output of the N sensor elements in response to the electrical signal and based on an output of the reference circuit in response to the electrical signal, and wherein the output of the reference circuit is indicative of a fault when the output of the reference circuit is different from a level determined as function of the output of the N sensor elements.