Semiconductor Airborne Radiation Measurement With Radon Compensation
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Solution Overview
Problem
Existing methods for measuring airborne alpha and beta radiation of artificial origin struggle with accurately distinguishing and compensating for contributions from natural radiation sources, particularly during rapid dynamic changes, leading to difficulties in setting alarm thresholds and reducing measurement accuracy.
Innovation Solution
A method using a semiconductor detector with energy threshold discrimination and compensation factors to differentiate between alpha and beta radiation of artificial and natural origin, employing a membrane filter and collimator to enhance separation and reduce energy loss, and calculating compensated count rates using specific formulas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the ABPD method is used to compensate for natural radiation contributions, then the measurement of artificial radiation is improved, but positive peaks appear in the calculated specific activity particularly when radon level is rapidly decreasing
Solution Approach 1:
The patent segments the radiation measurement into multiple energy channels, specifically measuring alpha particles in different energy ranges (5.4-5.8 MeV and 5.8-6.5 MeV) and beta particles in different energy ranges. This segmentation allows independent compensation calculations for each channel, preventing the positive peak artifact that occurs in the ABPD method during rapid radon level changes.
Solution Approach 2:
The patent changes the measurement parameters by introducing energy threshold discrimination with specific voltage settings (e.g., 1100 mV for 5.8 MeV alpha particles, 800 mV for beta particles). By measuring count rates in multiple energy channels and applying different compensation factors to each channel, the system achieves accurate compensation without the positive peak problem that plagues the ABPD method.
2Measurement precision
If energy threshold discrimination is used to separate alpha and beta radiation, then radiation contributions of artificial origin can be separated from natural origin, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical or chemical separation systems with an electronic measurement and evaluation system. By using a semiconductor detector with electronic energy threshold discrimination and a microprocessor-based evaluation unit that applies compensation formulas, the system achieves radiation source differentiation without the mechanical complexity of physical separation apparatus.
3Measurement precision
If a semiconductor detector with energy threshold discrimination is used, then measurement accuracy in dynamic conditions is improved, but the device becomes less suitable for mobile systems
Solution Approach 1:
The patent replaces bulky traditional radiation detection systems with a compact semiconductor detector and integrated microprocessor evaluation unit. This electronic substitution dramatically reduces the device size and weight while maintaining high measurement accuracy during dynamic radiation changes, making the system suitable for mobile and portable applications.
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
Effectively separates and compensates for natural radiation contributions, enhancing measurement accuracy and enabling precise detection of artificial radiation even in dynamic conditions, suitable for small and mobile systems.
Implementation Method 1
a number A1 of particles are counted that hit the semiconductor detector and have an energy greater than a first energy threshold and less than a second energy threshold
Data Source
Figure 1~2
AI summary
Method for measuring airborne alpha and beta radiation of artificial origin using a semiconductor detector, - wherein the following steps are performed to measure the airborne alpha radiation of artificial origin during a given time interval: - counting a number A1 of particles striking the semiconductor detector that have an energy greater than a first energy threshold (S1) and less than a second energy threshold (S2), - counting a number A2 of particles striking the semiconductor detector that have an energy within a given energy range (EB) around the Po-218 energy line, - calculating a compensated count rate Aa of alpha particles as a function of the first count rate A1 and the second count rate A2, and - determining a measurand that characterizes the airborne alpha radiation of artificial origin.based on the compensated count rate Aa of alpha particles, and - wherein the following steps are performed to measure the airborne beta radiation of artificial origin during the specified time interval: - counting a number A3 of particles that hit the semiconductor detector and have an energy less than the first energy threshold (S1), - counting a number A4 of particles that hit the semiconductor detector and have an energy greater than the second energy threshold (S2), - calculating a compensated count rate Aß of beta particles as a function of the third count rate A3 and the fourth count rate A4, and - determining a measurand that characterizes the airborne beta radiation of artificial origin, based on the compensated count rate Aß of beta particles.