Optical Modulator Shields Gamma Detector from X-ray Saturation
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Solution Overview
Problem
Gamma radiation detectors are susceptible to stray X-ray radiation, leading to interference and saturation issues, which necessitates intermittent operation and prolonged delays in imaging procedures, especially when used in conjunction with X-ray imaging systems.
Innovation Solution
A gamma radiation detector with an optical modulator positioned between the scintillator array and photodetector array, allowing for controlled modulation of scintillation light to prevent unwanted X-ray-induced saturation, enabling continuous operation without the need for saturation recovery time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If gamma radiation detectors are operated in conjunction with X-ray imaging systems, then co-registered X-ray and gamma images can be obtained, but stray X-ray radiation causes saturation of the gamma photodetectors requiring prolonged delays and intermittent operation
Solution Approach 1:
The detector is divided into functionally independent segments: an X-ray detector portion and a gamma detector portion, each optimized for its specific radiation type. The optical modulator further segments the gamma detection path, allowing independent control of light transmission to photodetectors. This segmentation enables the X-ray and gamma imaging functions to operate simultaneously without mutual interference, eliminating the need for sequential intermittent operation and saturation recovery delays.
Solution Approach 2:
An optical modulator is introduced as an intermediary component between the gamma scintillator array and the photodetector array. This modulator selectively controls the transmission of scintillation light to the photodetectors, acting as a gate that prevents saturation by blocking excess light during high-flux conditions while allowing normal detection during low-flux conditions. This intermediary enables continuous operation without saturation recovery time.
2Reliability
If the optical modulator cross-sectional area is increased to match or exceed the photodetector pixel area, then complete modulation coverage is achieved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The optical modulator pixels are designed with a universal design principle where each modulator pixel serves multiple functions: it modulates the scintillation light signal, provides structural support for the layered detector configuration, and maintains mechanical alignment between the scintillator array and photodetector array. The modulator pixels can be configured in different patterns (e.g., alternating transparent/opaque) to achieve various modulation schemes, providing design flexibility without increasing fundamental complexity.
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
The optical modulator effectively shields the photodetector from stray X-ray radiation, allowing for uninterrupted gamma radiation detection and reducing the duration of imaging procedures by eliminating the need for delays, thereby improving the efficiency of combined gamma and X-ray imaging.
Implementation Method 1
an optical modulator disposed between the gamma scintillator array and the photodetector array for modulating a transmission of the scintillation light between the gamma scintillator array and the photodetector array
Implementation Method 2
a gamma scintillator array comprising a plurality of first scintillator elements for generating first scintillation light in response to received gamma quanta
Implementation Method 3
a first photodetector array for detecting the first scintillation light generated by the gamma scintillator array
Implementation Method 4
The optical modulator effectively shields the photodetector from stray X-ray radiation, allowing for uninterrupted gamma radiation detection
Data Source
AI summary
The invention relates to a combined detector (660) comprising a gamma radiation detector (100) and an X-ray radiation detector (661). The gamma radiation detector (100) comprises a gamma scintillator array (101x, y), an optical modulator (102) and a first photodetector array (103a, b) for detecting the first scintillation light generated by the gamma scintillator array (101x, y). The optical modulator (102) is disposed between the gamma scintillator array (101x, y) and the first photodetector array (103a, b) for modulating a transmission of the first scintillation light between the gamma scintillator array (101x, y) and the first photodetector array (103a, b). The optical modulator (102) comprises at least one optical modulator pixel having a cross sectional area (102′) in a plane that is perpendicular to the gamma radiation receiving direction (104). The cross sectional area of each optical modulator pixel (102′) is greater than or equal to the cross sectional area of each photodetector pixel (103′a, b).