Direct-Convert X-Ray Detector Polarization Control
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Solution Overview
Problem
Direct-converting X-ray radiation detectors using semiconductor materials face polarization issues at high radiant flux densities, limiting their ability to convert high radiation densities into electrical pulses, especially in CT systems, due to the low mobility of charge carriers and intrinsic impurities, which affects the detector's service life and count rate.
Innovation Solution
The semiconductor material is indirectly irradiated using a reflection layer on the collimator to uniformly distribute additional radiation, generating charge carriers that counteract polarization, allowing for uniform charge carrier generation across the semiconductor surface and preventing drift during X-ray radiation detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the semiconductor material is irradiated with additional X-ray radiation to prevent polarization, then the detector can maintain accurate measurement at high radiant flux densities, but the patient is exposed to additional radiation dose
Solution Approach 1:
The patent introduces an intermediary substance (halogenated hydrocarbon liquid or gas) that absorbs X-ray radiation and converts it to chemical energy, which then generates charge carriers in the semiconductor material. This intermediary mechanism allows polarization prevention without direct X-ray irradiation of the detector, thereby avoiding additional patient radiation dose while maintaining measurement accuracy.
2Stability of the object's composition
If the semiconductor material is irradiated with infrared radiation to generate charge carriers and prevent polarization, then uniform charge carrier generation is achieved, but the radiation source and irradiation system become more complex
Solution Approach 1:
The patent changes the physical state and properties of the semiconductor material by introducing a halogenated hydrocarbon substance that can be in liquid or gas form. This substance absorbs X-ray radiation and generates charge carriers through chemical decomposition, providing uniform charge carrier generation without requiring complex infrared irradiation systems. The parameter change approach simplifies the overall system while achieving the desired uniformity.
3Stability of the object's composition
If additional charge carriers are generated in the semiconductor material before X-ray irradiation to equalize polarization, then the electrical field remains constant during measurement, but the detector requires precise control of charge carrier concentration
Solution Approach 1:
The patent employs a self-service mechanism where the halogenated hydrocarbon substance automatically generates charge carriers in the semiconductor material when exposed to X-ray radiation. This self-generating process eliminates the need for external control mechanisms to regulate charge carrier concentration, as the substance inherently provides uniform charge carrier generation throughout the semiconductor material, thereby maintaining electrical field stability without complex control systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach prevents polarization and drift in the detector, enabling accurate measurement of high radiant flux densities in CT systems without exposing patients to additional radiation, ensuring a direct link between X-ray attenuation and detector count rate, and reducing image artifacts.
Implementation Method 1
the semiconductor material is irradiated with additional radiation, which generates charge carriers in the semiconductor material
Implementation Method 2
the at least one collimator has at least one reflection layer on a side facing the semiconductor material, off which the additional radiation is reflected onto the semiconductor material
Data Source
AI summary
A direct-converting x-ray radiation detector is disclosed for detecting x-ray radiation, in particular for use in a CT system. In an embodiment, the detector includes a semiconductor material used for detecting the x-ray radiation; at least one collimator; and at least one radiation source, to irradiate the semiconductor material with additional radiation. In at least one embodiment, the at least one collimator includes at least one reflection layer on a side facing the semiconductor material, on which the additional radiation is reflected to the semiconductor material. In another embodiment, a CT system including the direct-converting x-ray radiation detector, and a method for detecting incident x-ray radiation via a direct-converting x-ray radiation detector, in particular for use in a CT system, are disclosed.