science

Neutron tomography

Neutron tomography is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Neutron tomography rather than just read about it. In short: Neutron tomography is a form of computed tomography involving the production of three-dimensional images by the detection of the absorbance of neutrons produced by a neutron source. It creates a three-dimensional image of an object by combining multiple planar images with a known separation.

Key takeaways

Neutron tomography belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Neutron tomography to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Neutron tomography from memory before moving on to harder problems.

Reference excerpt

Neutron tomography is a form of computed tomography involving the production of three-dimensional images by the detection of the absorbance of neutrons produced by a neutron source. It creates a three-dimensional image of an object by combining multiple planar images with a known separation. It has a resolution of down to 25 μm. Whilst its resolution is lower than that of X-ray tomography, it can be useful for specimens containing low contrast between the matrix and object of interest; for instance, fossils with a high carbon content, such as plants or vertebrate remains. Neutron tomography results in the short- to medium-term radioactivation of imaged samples, with the form and period of residual radioactivity dependent on the elemental and isotopic composition of the samples, with elements. Of notable concern are samples containing appreciable levels of certain elements such as cobalt. In practice, this neutron activation is low and short-lived such that the method is considered non-destructive, and of potential benefit, enabling the qualitative and quantitative analysis of major, minor, trace or rare elements via instrumental neutron activation analysis. The increasing availability of neutron imaging instruments at research reactors and spallation sources via peer-reviewed user access programs has seen neutron tomography achieve increasing impact across diverse applications including earth sciences, palaeontology, cultural heritage, materials research and engineering. In 2022, it was reported in the journal Gondwana Research that an ornithopod dinosaur was serendipitously discovered by neutron tomography in the gut content of Confractosuchus, a Cretaceous crocodyliform from the Winton Formation of central Queensland, Australia. This is the first time that a dinosaur has been discovered using neutron tomography, and to this day, the partially digested dinosaur remains entirely embedded within the surrounding matrix. That same year, in the journal Science, researchers announced the discovery of a 380-million-year-old three-dimensionally preserved heart inside a fossilised fish. The two-chambered, S-shaped heart is 250-million-years older than the previous oldest vertebrate heart and revealed the early evolution of the heart structure found in vertebrates, including humans, today.

See also Winkler, B. (2006). "Applications of Neutron Radiography and Neutron Tomography". Reviews in Mineralogy and Geochemistry. 63 (1): 459–471. Bibcode:2006RvMG...63..459W. doi:10.2138/rmg.2006.63.17. Schwarz, D.; Vontobel, P. L.; Eberhard, H.; Meyer, C. A.; Bongartz, G. (2005). "Neutron tomography of internal structures of vertebrate remains: a comparison with X-ray computed tomography" (PDF). Palaeontologia Electronica. 8 (30). Mays, C.; Cantrill, D. J.; Stilwell. J. D.; Bevitt. J. J. (2017). "Neutron tomography of Austrosequoia novae-zeelandiae comb. nov. (Late Cretaceous, Chatham Islands, New Zealand): implications for Sequoioideae phylogeny and biogeography". Journal of Systematic Palaeontology. 16 (7): 551–570. doi:10.1080/14772019.2017.1314898. S2CID 133375313.

References

Illustrations

Worked examples

Example 1 — a first encounter with Neutron tomography

Start with the simplest possible case. Write down what Neutron tomography claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Neutron tomography before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Neutron tomography ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Neutron tomography

In research: Neutron tomography appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Neutron tomography in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Neutron tomography is common in secondary-school and first-year university syllabi. It links to neighbouring topics Neutron instrumentation, Tomography, so understanding it makes those chapters shorter.
In everyday life: Look for Neutron tomography outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Neutron tomography in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Neutron tomography means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Neutron tomography out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Neutron tomography in simple terms?

Why does Neutron tomography matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Neutron tomography?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Neutron tomography.