Imaging device for imaging radiation

Abstract

A semiconductor radiation imaging device is disclosed which includes an array of image elements, each image element of said array comprising an image element detector cell which generates charge in response to radiation incident on said image element and image element circuitry for accumulating said charge from said image element detector cell and for selectively outputting a signal representative of accumulated charge. The imaging device further includes a radiation sensor element, said radiation sensor element comprising a radiation detector cell integral with said image element detector cells for generating charge in response to incident radiation on said radiation sensor element and a radiation sensor output for continuously supplying charge from said radiation detector cell. Also disclosed is an imaging system employing image devices as described above, and a method of imaging radiation.

Description

[0001] This is a continuation of application Ser. No. 09 / 261,747 filed Mar. 3, 1999.[0002] This invention relates to a self-triggering imaging device for imaging radiation, in particular, but not exclusively, to an imaging device for a self-triggerable imaging system; the imaging device comprising an array of image elements.BACKGROUND TO INVENTION[0003] Imaging devices comprising an array of image elements of various types are known.[0004] Charged coupled image sensors (also known as charged coupled devices (CCDs)) form one type of known imaging device. A CCD type device operates in the following way:[0005] 1. Charge is accumulated within a depletion region created by an applied voltage. For each pixel (image cell) the depletion region has a potential well shape and constrains electrons under an electrode gate to remain within the semiconductor substrate.[0006] 2. Voltage is applied as a pulse to the electrode gates of the CCD device to clock each charge package to an adjacent pixel...

AI Technical Summary

Problems solved by technology

During this process, additional charge cannot be accumulated.

CCD devices suffer from disadvantages of limited dynamic range, due to the limited capacity of the potential well inside the semiconductor substrate, and also to the inactive times during which an image is read out.

Pulse counting semiconductive pixel devices also have the disadvantage of limited dynamic range.

As these devices read the pixel contact when a hit is detected, they suffer from saturation problems at high counting rates.

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