Radiation Detection Shielding for Magnetic Noise Reduction

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Solution Overview

Problem

Radiation detection apparatuses face challenges in reducing image noise caused by alternating current magnetic fields, particularly those arriving from the horizontal direction with unknown frequency and amplitude, as existing techniques either fail to eliminate noise effectively or decrease imaging speed.

Innovation Solution

The apparatus incorporates a conductive member connected to the ground of the readout and output circuits, forming a closed circuit with a reduced cross-section area to minimize inductive current induced by horizontal alternating current magnetic field noise, thereby reducing image noise without affecting imaging speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional radiation detection apparatus is used in an environment with high power equipment, then the apparatus can operate, but alternating current magnetic field noise causes line artifacts and image noise

Engineering Contradiction:
Improveimage qualityVSAvoidmagnetic field noise
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful alternating current magnetic field noise into a beneficial signal by detecting the noise-induced charge in conversion elements and using it to calculate noise components, which are then subtracted from the final image to eliminate line artifacts

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent implements a feedback mechanism where the detected noise signal is processed to determine noise components, and these components are fed back to correct the final image, creating a closed-loop noise reduction system

Inventive Principle:
Principle #23Feedback

2Reliability

If subtraction processing is used to eliminate noise, then image noise can be reduced, but the frequency or amplitude of alternating current magnetic field may change between dark image and radiation image acquisition

Engineering Contradiction:
Improvenoise elimination effectivenessVSAvoidnoise frequency and amplitude variation
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent performs preliminary detection of alternating current magnetic field noise before acquiring the final radiation image, and uses this detected noise to calculate noise components that are then applied to correct the final image, ensuring noise reduction effectiveness regardless of frequency or amplitude changes

Inventive Principle:
Principle #10Preliminary action

3Reliability

If readout times are adjusted to eliminate noise by subtraction processing, then the time from start of obtaining dark image to start of obtaining radiation image must be an integer multiple of external magnetic field cycle, resulting in decreased imaging speed

Engineering Contradiction:
Improvenoise eliminationVSAvoidimaging speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the mechanical timing adjustment approach with an electronic signal processing approach, where noise is detected and processed electronically to determine noise components for image correction, eliminating the need for precise timing synchronization and maintaining high imaging speed

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This configuration significantly reduces image noise by minimizing the cross-section area through which alternating current magnetic field noise penetrates, effectively addressing noise from both the X and Y directions regardless of noise frequency or amplitude, without requiring specific noise reduction controls during imaging.

Implementation Method 1

forming a closed circuit with a reduced cross-section area to minimize inductive current induced by horizontal alternating current magnetic field noise

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3038349B1Radiation detection apparatus and radiation imaging system
Publication Date: 2018.03.14 CANON KK
  • EP3038349B1 patent drawingFigure 1A
  • EP3038349B1 patent drawingFigure 1B
  • EP3038349B1 patent drawingFigure 2A~2B

AI summary

A radiation detection apparatus includes a planar detection unit which has a two-dimensional array (2) of elements (1) which obtain electrical signals based on radiation, and detects radiation upon irradiation, a driving circuit (9) which drives switches (3) for causing the elements to output the electrical signals, an obtaining circuit (6) which obtains the electrical signals from the elements in accordance with the switches being driven, a support base (12) on which the driving circuit and the obtaining circuit are arranged, and a conductive member (13) having a part which is arranged in front of the detection unit when viewed from a radiation source which performs irradiation with radiation used for imaging and is electrically connected to ground of the driving circuit and ground of the obtaining circuit.