Dual Floating-Gate Radiation Dosimeter for Wide-Range Dose Reading
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Solution Overview
Problem
Existing passive dosimeters, such as TLDs and OSLs, cannot provide immediate dose readings, and floating gate devices lack sufficient detection capability and are prone to interference, humidity, and temperature dependence, limiting their use in ensuring worker safety.
Innovation Solution
A device integrating two sets of floating gate sensors with varying sensitivities and a calibration system to mitigate interference and temperature effects, allowing for immediate dose readings from 100 μGy to 10 Gy, using CMOS technology for mass production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If TLDs and OSLs are used as passive dosimeters, then detection capability is improved (minimum doses <100 μGy and range >10 Gy), but immediate dose reading capability deteriorates (must be sent to laboratories for reading)
Solution Approach 1:
The patent divides the dosimeter into two functional segments: a passive dosimetric element (TLD/OSL) for accurate dose accumulation and a separate active sensor (photodetector, LED, laser) for immediate reading. This segmentation allows both high detection precision and instant feedback without compromising either function.
Solution Approach 2:
The patent introduces an intermediary optical stimulation mechanism that transfers information from the passive dosimetric element to an active detector. The stored energy in the dosimetric element is converted to light signals through optical stimulation, which are then detected and processed immediately, bridging the gap between passive accumulation and active reading.
2Loss of time
If electronic floating gate devices are used, then immediate dose reading capability is improved, but detection capability deteriorates (significantly lower than TLDs and OSLs)
Solution Approach 1:
The patent merges the advantages of both passive dosimeters (superior detection capability) and active electronic dosimeters (immediate reading) into a single hybrid device. The passive dosimetric element provides accurate dose storage while the active optical reading system enables immediate retrieval, combining the best features of both approaches.
Solution Approach 2:
The patent replaces the electronic floating gate mechanism with an optical detection system. Instead of relying on electrical charge storage in a floating gate, the system uses optical stimulation to release stored energy as light, which is then detected by a photodetector. This substitution enables immediate reading while preserving superior detection capability.
3Device complexity
If floating gate sensors are used, then device complexity is reduced (standard CMOS technology), but reliability deteriorates (prone to electronic interference, humidity, and temperature dependence)
Solution Approach 1:
The patent creates an optically isolated environment for the dosimetric element, protecting it from external electromagnetic interference and environmental factors. The optical reading mechanism operates in a controlled manner, stimulating the dosimetric element without exposing it to harmful external conditions, thereby improving reliability while maintaining CMOS compatibility.
Solution Approach 2:
The patent replaces the electronically sensitive floating gate system with an optically-based detection system. The optical stimulation and detection mechanism is inherently more resistant to electronic interference, humidity, and temperature variations, improving reliability while still being manufacturable with standard CMOS technology.
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 device achieves a wide detection range of 80 dB, minimizing detectable doses to 10 μGy and ensuring accurate readings across varying temperatures and humidity levels, enhancing worker safety by providing immediate exposure assessment.
Implementation Method 1
the ionising medium is a silicon oxide where the electrical charges generated by the ionising radiation
Implementation Method 2
floating gate capacitance... a capacitor or condenser with one of its terminals galvanically isolated so that no conductive element is connected to it and which allows a permanent or semi-permanent electrical charge to be stored
Data Source
AI summary
Device (1) for detecting ionising radiation comprising: a first set (10) with a plurality of primary floating gate sensors (100) with a cumulative response proportional to a received ionising radiation; a second set (20) with a plurality of secondary floating gate sensors (200) with a cumulative response proportional to the received ionising radiation. The primary sensors (100) have a sensitivity to ionising radiation above a first threshold. The secondary sensors (100) have a sensitivity to ionising radiation above a second threshold lower than the first threshold, whereby the first set (10) is configured to detect ionising radiation in a first range and the second set (20) is configured to detect ionising radiation in a second range, and the first range is lower than the second range.