Neutron tomography is a form of

computed tomography A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...

involving the production of three-dimensional images by the detection of the absorbance of

neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons behav ...

s produced by a

neutron source A neutron source is any device that emits neutrons, irrespective of the mechanism used to produce the neutrons. Neutron sources are used in physics, engineering, medicine, nuclear weapons, petroleum exploration, biology, chemistry, and nuclear p ...

. 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 A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...

, it can be useful for specimens containing low contrast between the

matrix Matrix most commonly refers to: * ''The Matrix'' (franchise), an American media franchise ** '' The Matrix'', a 1999 science-fiction action film ** "The Matrix", a fictional setting, a virtual reality environment, within ''The Matrix'' (franchi ...

and object of interest; for instance,

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s with a high carbon content, such as plants or

vertebrate Vertebrates () comprise all animal taxon, taxa within the subphylum Vertebrata () (chordates with vertebral column, backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the ...

remains. Neutron tomography can have the unfortunate side-effect of leaving imaged samples radioactive if they contain appreciable levels of certain elements such as

cobalt Cobalt is a chemical element with the symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, ...

, however in practice this

neutron activation Neutron activation is the process in which neutron radiation induces radioactivity in materials, and occurs when atomic nuclei capture free neutrons, becoming heavier and entering excited states. The excited nucleus decays immediately by emitti ...

is low and short-lived such that the method is considered

non-destructive Minimally invasive procedures (also known as minimally invasive surgeries) encompass surgical techniques that limit the size of incisions needed, thereby reducing wound healing time, associated pain, and risk of infection. Surgery by definition ...

. The increasing availability of

neutron imaging Neutron imaging is the process of making an image with neutrons. The resulting image is based on the neutron attenuation properties of the imaged object. The resulting images have much in common with industrial X-ray images, but since the image i ...

instruments at

research reactors Research reactors are nuclear fission-based nuclear reactors that serve primarily as a neutron source. They are also called non-power reactors, in contrast to power reactors that are used for electricity production, heat generation, or maritim ...

and

spallation Spallation is a process in which fragments of material ( spall) are ejected from a body due to impact or stress. In the context of impact mechanics it describes ejection of material from a target during impact by a projectile. In planetary p ...

sources via

peer-reviewed Peer review is the evaluation of work by one or more people with similar competencies as the producers of the work ( peers). It functions as a form of self-regulation by qualified members of a profession within the relevant field. Peer revie ...

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 ''Gondwana Research'' is a peer-reviewed scientific journal with an "all earth science" scope and an emphasis on the origin and evolution of continents. It is part of the Elsevier Elsevier () is a Dutch academic publishing company speciali ...

that an

ornithopod Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (), that started out as small, bipedal running grazers and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous worl ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

was serendipitously discovered by neutron tomography in the gut content of ''

Confractosuchus ''Confractosuchus'' is a genus of extinct eusuchian crocodyliform from the Cretaceous Winton Formation of Australia. Described as a macro-generalist, ''Confractosuchus'' was found with the bones of a juvenile ornithopod dinosaur in its abdome ...

'', a Cretaceous

crocodyliform Crocodyliformes is a clade of crurotarsan archosaurs, the group often traditionally referred to as "crocodilians". They are the first members of Crocodylomorpha to possess many of the features that define later relatives. They are the only ps ...

from the

Winton Formation The Winton Formation is a Cretaceous geological formation in central-western Queensland, Australia. It is late Albian to early Turonian in age. The formation blankets large areas of central-western Queensland. It consists of sedimentary rocks s ...

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

References

{{Reflist Tomography Neutron instrumentation

See also

References