Radon Diffusion Chamber Layout for Real-Time Alpha Spectrum Sensing

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Solution Overview

Problem

Existing radon dosimeters often require waiting for an equilibrium between radon gas and secondary decay products to make accurate determinations, lacking real-time capabilities due to inclusion of secondary radon decay product contributions.

Innovation Solution

A radon dosimeter design with a diffusion chamber and radon sensing arrangement, where detectors are positioned close to ensure minimal distance from decay points, using semiconductor detectors and an energy spectrum analysis to filter out secondary decay product contributions, and employing an energy window and time stamps for precise radon concentration determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If detectors are positioned close to the diffusion chamber walls (within 20 mm), then real-time radon gas decay detection is improved, but detection of secondary decay products increases

Engineering Contradiction:
Improveresponse timeVSAvoidradon concentration accuracy
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The patent applies local quality by creating zones of different detector distances within the diffusion chamber. The chamber is divided into regions where some areas have detectors within 20 mm for real-time detection, while other areas maintain larger distances to reduce secondary decay product interference. This spatial differentiation allows simultaneous optimization of both response time and measurement precision for different detection needs.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The diffusion chamber is segmented into multiple detection zones with varying detector placements. By dividing the chamber into sections with different detector distances (some within 20 mm, others farther), the system can process signals from different zones separately, enabling real-time detection while filtering out secondary decay product contributions through selective zone analysis.

Inventive Principle:
Principle #1Segmentation

2Quantity of substance

If the diffusion chamber volume is increased to improve radon gas accumulation, then detection sensitivity improves, but the distance from decay points to detectors increases reducing detection accuracy

Engineering Contradiction:
Improveradon gas accumulationVSAvoidalpha particle energy measurement
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent transitions from a single large-volume chamber to a multi-chamber or multi-zone configuration where each smaller zone maintains short detector distances. By adding the dimension of spatial zonation within the overall chamber structure, the system achieves both sufficient total radon accumulation (across multiple zones) and accurate local detection (within each zone where detectors are within 20 mm of walls).

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Device complexity

If passive radon dosimeters are used to avoid power supply requirements, then device simplicity is improved, but only accumulated exposure over time can be determined

Engineering Contradiction:
Improvepower supply requirementsVSAvoidmeasurement frequency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent implements self-service by designing the active detection system to automatically perform calibration, background subtraction, and radon concentration calculation without external intervention. The system uses built-in reference measurements and automated signal processing to maintain continuous real-time monitoring, making the complexity of active detection acceptable by eliminating the need for manual laboratory analysis and repeated measurements.

Inventive Principle:
Principle #25Self-service

4Measurement precision

If secondary radon decay products are included in measurements to improve signal strength, then detection sensitivity improves, but accurate radon gas concentration determination becomes difficult

Engineering Contradiction:
Improvedetection sensitivityVSAvoidradon gas vs decay product differentiation
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent employs feedback mechanisms where the system continuously monitors detector signals, compares them against expected radon gas decay patterns, and adjusts measurements accordingly. By using reference measurements and comparing actual signals against modeled expectations, the system can distinguish radon gas decay from secondary decay products, maintaining detection sensitivity while preserving accurate radon gas concentration determination.

Inventive Principle:
Principle #23Feedback

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

Enables continuous, real-time, and accurate radon gas concentration measurement by distinguishing direct radon gas decay from secondary decay products, allowing immediate alerts for hazardous levels.

Implementation Method 1

Semiconductor technology may be used for detecting alpha particles due to the fact that an alpha particle hitting a photodiode creates electron-hole pairs which will cause a small current to be generated

Methodology Applied
Scientific EffectAlpha particle detection through electron-hole pair generation: Photoelectric Effect

Implementation Method 2

a diffusion chamber, that comprises a number of openings that allow radon gas to enter and exit

Methodology Applied
Scientific EffectRadon gas diffusion: Diffusion

Data Source

PatentEP4278217B1Device and method for determining radon concentration
Publication Date: 2026.03.18 RADONOVA LAB AB
  • EP4278217B1 patent drawingFigure 1a~1b
  • EP4278217B1 patent drawingFigure 2a~2c
  • EP4278217B1 patent drawingFigure 3a~3b

AI summary

In accordance with one or more embodiments herein, a device (100) for determining radon concentration is provided. The device (100) comprises a diffusion chamber (130), that comprises a number of openings (210) that allow radon gas to enter and exit, and a radon sensing arrangement (150). The radon sensing arrangement (150) comprises at least one processing device (220) and one or more detectors (250), arranged inside the diffusion chamber (130) in such a way that no part of the diffusion chamber (130) is located at a distance, perpendicular to the detector (250), of more than 20 mm from the closest part of a detector (250). The at least one processing device (220) is arranged to determine the radon concentration by analyzing and processing the energy spectrum of alpha particles detected by the one or more detectors.