Diamond Spin Sensor Shielding for Radiation-Hard Field Measurement

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Solution Overview

Problem

Diamond spin sensors using optical fibers as waveguides are susceptible to degradation from X-rays or electron beams, making them unusable in environments with radiation.

Innovation Solution

A diamond spin sensor configuration that includes a diamond with electron spin and an optical waveguide, with shielding and protective metal members to prevent exposure of the optical waveguide to radiation, allowing measurement of magnetic fields, electric fields, and temperature in environments with X-rays or electron beams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If optical fibers are used as waveguides to transmit excitation light and fluorescence, then the sensor can be miniaturized and integrated, but the optical fibers are degraded by X-rays or electron beams, making the sensor unusable in radiation environments

Engineering Contradiction:
Improvesensor sizeVSAvoidoptical waveguide durability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent extracts the optical waveguide function from the radiation-sensitive optical fiber and implements it using a metal waveguide instead. The metal waveguide transmits microwaves from the microwave source to the diamond sensor, eliminating the use of optical fibers in the radiation path while maintaining the sensor's miniaturization benefits.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a metal waveguide as an intermediary component between the microwave source and the diamond sensor. This metal waveguide serves as a mediator that transmits microwave signals without being directly exposed to radiation, protecting the sensitive optical components while enabling the sensor to function in radiation environments.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If metal wiring is used to transmit electrical signals from the sensor, then the sensor can be connected to external circuits, but ionization caused by X-rays or electron beams produces noise in the metal wiring

Engineering Contradiction:
Improveelectrical connectionVSAvoidionization noise
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the metal wiring system with a diamond-based electrical connection system. The diamond substrate, which has high electrical breakdown strength and radiation hardness, is used to transmit electrical signals from the sensor to external circuits, eliminating ionization noise while maintaining electrical connectivity.

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

Solution Approach 2:

The patent employs a composite structure combining diamond material with metal components. The diamond substrate provides radiation-hard electrical connections, while metal components are used for microwave transmission through the metal waveguide. This composite approach leverages the advantages of both materials to achieve both electrical connectivity and radiation resistance.

Inventive Principle:
Principle #40Composite materials

3Strength

If resin coating is applied to protect the sensor, then the sensor can be protected from environmental damage, but the resin coating is degraded by X-rays or electron beams

Engineering Contradiction:
Improvesensor protectionVSAvoidcoating durability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent eliminates the need for protective resin coating by using inherently radiation-hard materials. The diamond substrate and metal waveguide are used directly without protective coatings, as these materials naturally resist radiation degradation, effectively replacing the protective function of resin with radiation-hard material selection.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the material parameter from organic resin to inorganic radiation-hard materials (diamond and metal). This parameter change fundamentally alters the radiation resistance characteristic, transforming the protective mechanism from a thin coating barrier to intrinsic material hardness against radiation.

Inventive Principle:
Principle #35Parameter changes

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 accurate measurement of magnetic fields, electric fields, and temperature in environments with radiation levels up to 1 µGy/h or more, preventing degradation of the optical waveguide and maintaining high sensitivity.

Implementation Method 1

When excited by a wavelength of 532 nm (i.e., green light), the NV center emits fluorescence at a wavelength of 637 nm (i.e., red light). The intensity of fluorescence emission varies with a spin state.

Methodology Applied
Scientific EffectFluorescence emission: Fluorescence

Implementation Method 2

The spin state is changed by magnetic resonance due to a magnetic field applied to the NV center and microwaves or radio waves

Methodology Applied
Scientific EffectMagnetic resonance: Resonance

Implementation Method 3

an optical waveguide that transmits excitation light to irradiate the diamond and fluorescence emitted from the diamond

Methodology Applied
Scientific EffectOptical waveguide transmission: Waveguide (optics)

Data Source

PatentEP4700419A1Diamond spin sensor and device mounted with same
Publication Date: 2026.02.25 NISSIN ELECTRIC CO LTD
  • EP4700419A1 patent drawingFigure 1
  • EP4700419A1 patent drawingFigure 2
  • EP4700419A1 patent drawingFigure 3

AI summary

A diamond spin sensor includes a diamond having a color center with electron spin, and an optical waveguide that transmits excitation light to irradiate the diamond and fluorescence emitted from the diamond, wherein in a state in which the diamond is disposed in an environment where radiation of 1 µGy/h or more is present, a magnetic field, an electric field, or a temperature in the environment is measured using the color center.