Photodiode Array Radiometric Level Measurement
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Solution Overview
Problem
Current radiometric measuring systems for fill level and density measurement are cumbersome due to the use of photomultipliers, which require complex voltage generation and have large space requirements.
Innovation Solution
A radiometric fill level or density measuring system utilizing a converter, photodiode, and evaluation unit to convert ionizing radiation into electromagnetic signals, with a semiconductor-based photodiode and a scintillation counter to enhance sensitivity and reduce noise, and a comparator to convert voltage pulses into digital signals, allowing only synchronized signals to contribute to the measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photomultipliers are used for radiometric measurement, then detection capability is achieved, but device complexity and space requirements increase
Solution Approach 1:
The patent replaces the photomultiplier tube (a vacuum tube-based device requiring complex high voltage generation) with a photodiode (a solid-state semiconductor device). This substitution eliminates the need for complex voltage generation circuits while maintaining radiation detection capability, directly resolving the contradiction between detection capability and device complexity
Solution Approach 2:
The patent employs multiple inexpensive photodiodes instead of a single expensive photomultiplier tube. While individual photodiodes have shorter lifetimes and lower individual sensitivity, the parallel arrangement of multiple cheap photodiodes achieves comparable or superior overall performance with reduced cost and simplified voltage requirements
2Reliability
If photomultipliers are used for radiometric measurement, then detection capability is achieved, but space requirements increase
Solution Approach 1:
The replacement of the bulky photomultiplier tube with compact solid-state photodiodes dramatically reduces the space required for the detection system. Multiple small photodiodes can be arranged in a compact array, achieving the necessary detection capability in a much smaller footprint than a single photomultiplier tube
Solution Approach 2:
The patent divides the detection function across multiple separate photodiodes rather than relying on a single large photomultiplier tube. This segmentation allows for compact arrangement of the detector elements and enables flexible positioning to achieve the required detection capability in limited space
3Measurement precision
If multiple photodiodes are combined, then sensitivity increases and dark pulses are suppressed, but device complexity increases
Solution Approach 1:
The patent combines multiple photodiodes into a single integrated detection system where their outputs are summed together. This merging approach increases overall sensitivity and allows for suppression of dark pulses through coincidence counting, while the combination logic can be implemented in a single integrated circuit rather than requiring complex external processing
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 system achieves improved sensitivity and reduced noise by using smaller, easier-to-control semiconductor photodiodes, effectively suppressing dark pulses and enhancing measurement accuracy with minimal space and cost requirements.
Implementation Method 1
The converter (101) is designed as a scintillation counter or scintillator, which converts the incident ionizing radiation into flashes of light
Implementation Method 2
The photodiode is used to at least partially convert the second radiation into an electrical signal z. B. a voltage signal
Implementation Method 3
According to a further exemplary embodiment of the invention, the photodiode is an avalanche photodiode (APD)
Data Source
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AI summary
According to one embodiment of the invention, the fill level or density of a medium in a tank is measured radiometrically by detecting the light flashes generated by a scintillator with an array of photodiodes. Corresponding voltage pulses are summed and analyzed for their relevance before being used to determine the fill level or density of the medium.