Neutron Target Substrate Surface Modification for Blistering Prevention

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Solution Overview

Problem

Existing neutron generating targets for boron neutron capture therapy face challenges such as hydrogen impregnation leading to blistering and reduced lifetime, which complicates their use in hospital environments and requires frequent servicing.

Innovation Solution

A neutron generating target with a modified substrate surface featuring periodic or non-periodic surface features created through material removal or addition processes, combined with a neutron source layer like lithium or beryllium, which is bonded to the substrate using thermal methods to reduce hydrogen concentration and prevent blistering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a flat substrate surface is used for neutron source layer deposition, then the manufacturing process is simple, but hydrogen impregnation causes blistering and reduced target lifetime

Engineering Contradiction:
Improvesubstrate surface preparation simplicityVSAvoidtarget lifetime
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The substrate surface is modified to have non-uniform local structures (dimples, protrusions, or graded roughness) that create varying proton stopping depths across the surface. This local quality variation prevents uniform hydrogen accumulation, thereby eliminating blistering while extending target lifetime without complicating the overall manufacturing process

Inventive Principle:
Principle #3Local quality

2Reliability

If the substrate surface is modified to prevent blistering, then target lifetime is extended, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvetarget lifetimeVSAvoidsurface modification process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The substrate surface undergoes controlled parameter changes through modification processes (such as etching, deposition, or mechanical treatment) that alter the surface topology to create non-uniform structures. These parameter changes in surface roughness and geometry enable varied proton penetration depths, preventing hydrogen accumulation and extending target lifetime while maintaining manageable manufacturing complexity

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If uniform proton stopping depth is achieved, then neutron production is consistent, but hydrogen concentration accumulates causing material damage

Engineering Contradiction:
Improveneutron production uniformityVSAvoidhydrogen concentration and material damage
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The substrate surface is deliberately made asymmetric or non-uniform with features such as dimples, protrusions, or varied roughness patterns. This asymmetry creates different proton stopping depths across the surface area, preventing uniform hydrogen concentration accumulation and the associated material damage, while still maintaining sufficient neutron production consistency through controlled design of the surface features

Inventive Principle:
Principle #4Asymmetry

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 modified target design significantly reduces blistering and extends the target's lifespan by ensuring a non-uniform proton stopping depth, thereby minimizing hydrogen concentration and material damage, facilitating more reliable and efficient neutron production for BNCT.

Implementation Method 1

modifying a surface of a target substrate to form one or more surface features... ensuring a non-uniform proton stopping depth

Methodology Applied
Scientific EffectIon beam scattering: Ion Beam

Implementation Method 2

heating the neutron source layer and the target substrate to an elevated temperature for a duration of time for form a bond between the neutron source layer and the target substrate

Methodology Applied
Scientific EffectThermal bonding: Heating

Data Source

PatentEP3635751B1Method and system for surface modification of substrate for ion beam target
Publication Date: 2024.08.07 NEUTRON THERAPEUTICS INC
  • EP3635751B1 patent drawingFigure 1A
  • EP3635751B1 patent drawingFigure 1B~1C
  • EP3635751B1 patent drawingFigure 1D

AI summary

Design and making methods of a neutrons generating target are described. In some embodiments, a surface of a target substrate can be modified to form one or more surface features. In some embodiments, a neutron source layer can be disposed on the surface of the target substrate. In some embodiments, the neutron source layer and the target substrate can be heated to an elevated temperature to form a bond between the two. In some embodiments, the surface modification of the target substrate can reduce blistering and material exfoliation in the target. The target can be used in boron neutron capture therapy.