Atom Probe

What Is NRA (Nuclear Reaction Analysis)?

NRA (Nuclear Reaction Analysis) is an ion-beam analysis technique used in materials science to measure the concentration vs. depth of certain elements in solid materials and thin films. It works by bombarding a sample with MeV-energy ions and detecting products from specific nuclear reactions (often under resonance conditions) so the reaction signal can be related to elemental concentration at a known depth.

NRA is especially valuable for light elements (most commonly hydrogen) near surfaces and shallow interfaces—where many conventional elemental methods struggle.

What NRA Is Used For

NRA is commonly applied to:

Hydrogen depth profiling in metals, coatings, and thin films (near-surface)
Light element profiling (method/reaction dependent; project-dependent)
Diffusion and uptake studies (e.g., hydrogen ingress after processing or service exposure)
Barrier layer evaluation (does a coating reduce hydrogen ingress? project-dependent)
Process comparisons (“what changed?”): before/after heat treatment, cleaning, plating, or environment exposure (project-dependent)
Failure analysis support: hydrogen-related embrittlement hypotheses, blistering, delamination drivers (project-dependent)

How NRA Works (Simple Explanation)

A known nuclear reaction is selected for the target element. One widely used example for hydrogen profiling uses a resonant reaction involving a ¹⁵N ion beam; the reaction yield is linked to hydrogen concentration at a depth determined by beam energy loss (stopping power) in the material.

Why Use NRA (vs. Other Elemental Methods)?

NRA is chosen when you need:

Depth-resolved light-element information near surfaces/interfaces (especially H)
High specificity from reaction physics (reduced ambiguity vs purely spectral overlap methods, project-dependent)
A complementary method to RBS/ERDA/PIXE or chemical analyses when the key question is where light elements sit in depth (project-dependent)

Sample Types We Support

NRA is typically used for solid samples such as (project-dependent):

Metals & alloys: coupons, parts, welded regions (H uptake/embrittlement-related studies)
Coatings & thin films: barrier layers, plated coatings, functional films
Ceramics and oxides (project-dependent): when charging/beam effects are manageable
Semiconductor-related layers (project-dependent): hydrogen in films/interfaces (sample/stack dependent)

Best practice: include a reference/control sample (known-good condition) for comparison-based conclusions.

Typical Workflows

Hydrogen Depth Profile (Most Common)

Best for: hydrogen ingress, outgassing-related questions, process comparisons

Define the depth range and region of interest
Acquire an H concentration vs depth profile
Compare reference vs suspect conditions (if provided)

“Before / After” Process Study

Best for: cleaning, heat treatment, plating, coating changes

Use a consistent measurement plan across conditions
Summarize the delta (peak concentration shifts, near-surface enrichment, profile broadening)

Root Cause Support (Multi-Technique)

Best for: failure investigations where hydrogen is a suspect driver

NRA depth profile + complementary microscopy/chemistry (e.g., SEM-EDS for morphology, XPS for surface chemistry, etc., project-dependent)
Mechanism-oriented interpretation and next-step verification plan

What You Receive

Element concentration vs depth results (units and reporting conventions defined per project)
Measurement conditions summary (beam/reaction channel notes at a practical level)
Comparison summary (reference vs suspect) with clear highlights
Practical interpretation: what changed, where it is in depth, and what it likely implies (project-dependent)

Sample Submission Guidelines

Please provide

Material type and your key question (H depth? comparison? failure hypothesis?)
Process/service history (heat, humidity, plating, corrosion exposure, etc.)
Any target depth range or interface of concern
Reference/control sample whenever possible
Handling restrictions (e.g., keep sealed/dry, avoid cleaning before analysis if surface state matters)

Packaging tips

Protect surfaces from fingerprints and rubbing (gloves + clean bags)
Label orientation and ROI clearly (photos help)
For near-surface hydrogen studies, avoid uncontrolled heating or prolonged ambient exposure after sampling (project-dependent)

FAQs

Is NRA destructive?

NRA uses MeV ions and can cause localized beam effects depending on material and dose; in many cases it’s treated as low-impact for the bulk sample but you should assume the analyzed area is “used” for further critical surface testing (project-dependent).