X-ray Detector Polarization Stabilization via Additional Radiation
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Solution Overview
Problem
Directly converting semiconductor detector elements used in x-ray detection, such as those based on CdTE, CdZnTe, and InP, suffer from time-dependent polarization effects due to stationary imperfections (traps) that lead to unpredictable changes in the electric field and photocurrent pulse shape, making it difficult to reproducibly detect X-ray radiation and calculate the energy or number of absorbed X-rays, especially in imaging applications like computed tomography.
Innovation Solution
A method is introduced where additional radiation is supplied to the semiconductor detector element to condition it, specifically to stabilize the polarization effects and maintain a consistent electric field, using a radiation source controlled by a control unit to set a desired value for optimal detection, which can include UV, infrared, or visible light sources, and even the x-ray source itself, to ensure reliable and reproducible x-ray detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If directly converting semiconductor detector elements are used for x-ray detection, then the detection speed and efficiency are improved, but time-dependent polarization effects occur due to stationary imperfections that cause unpredictable changes in electric field and photocurrent pulse shape
Solution Approach 1:
The patent applies preliminary action by irradiating the semiconductor detector element with additional radiation (such as light from LED sources) before and during the x-ray measurement process. This pre-conditioning of the detector stabilizes the electric field and reduces polarization effects, ensuring that the detector is in a known, stable state before actual x-ray detection begins, thereby improving reproducibility without sacrificing detection speed
2Reliability
If additional radiation is supplied to condition the semiconductor detector element, then the polarization effects are stabilized and detection becomes reproducible, but the device complexity increases due to additional radiation sources and control mechanisms
Solution Approach 1:
The patent implements multi-functionality by using the same semiconductor detector element for both x-ray detection and light-based conditioning. The detector serves dual purposes: detecting x-rays during measurement and receiving conditioning radiation to stabilize its electrical properties. This eliminates the need for separate conditioning devices and reduces overall system complexity while maintaining detection reliability
Solution Approach 2:
The patent introduces light (electromagnetic radiation in the visible or UV range) as an intermediary substance to condition the semiconductor detector. This light acts as a mediator that modifies the electrical state of the detector without directly interfering with the x-ray detection process, enabling stable operation while keeping the system relatively simple through the use of conventional light sources like LEDs
3Stability of the object's composition
If the semiconductor detector element is irradiated to stabilize polarization, then the electric field remains consistent over time, but energy consumption increases due to continuous or repeated irradiation
Solution Approach 1:
The patent applies periodic action by supplying additional radiation to the semiconductor detector element at specific intervals or at defined stages of the measurement process, rather than continuously. The conditioning radiation can be applied before measurements begin and/or during idle periods between x-ray exposures, maintaining electric field stability while minimizing unnecessary energy consumption during active detection phases
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 allows for unambiguous and reproducible detection of X-ray radiation, stabilizing the semiconductor detector element's response over time, enabling reliable x-ray imaging by compensating for polarization effects and maintaining detector sensitivity invariant during measurements, thus improving the accuracy and reliability of x-ray imaging applications.
Implementation Method 1
Scintillation detectors first convert X-rays photochemically into light quanta which have a suitable energy in order to enable the light quanta to be detected using a semiconductor diode (photodiode), for example
Implementation Method 2
additional radiation is supplied to the semiconductor detector element with the aid of a radiation source... UV, infrared, or visible light sources
Data Source
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AI summary
The invention relates to a method for detecting x-rays (R) using an x-ray detector (100) which has a direct-conversion semiconductor detector element (150a, 150b). Additional radiation (K) is supplied to the semiconductor detector element (150a, 150b) using a radiation source (210a, 210b), and the supply of the additional radiation (K) is controlled and/or regulated on the basis of a specified target value (Ta, Tb, Tc). In particular, the target value can be specified in a variable manner over time as a sequence of target values. The invention further relates to an x-ray detector system (200) with which the method can be carried out.