Nuclear orientation, in

nuclear physics Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics, which studies the ...

, is the directional ordering of an assembly of nuclear spins with respect to some axis in space. It is one of the

nuclear spectroscopy Nuclear spectroscopy is a superordinate concept of methods that uses properties of a nucleus to probe material properties. By emission or absorption of radiation from the nucleus information of the local structure is obtained, as an interaction of ...

methods. A

nuclear Nuclear may refer to: Physics Relating to the nucleus of the atom: * Nuclear engineering *Nuclear physics *Nuclear power *Nuclear reactor *Nuclear weapon *Nuclear medicine *Radiation therapy *Nuclear warfare Mathematics *Nuclear space *Nuclear ...

level with

spin Spin or spinning most often refers to: * Spinning (textiles), the creation of yarn or thread by twisting fibers together, traditionally by hand spinning * Spin, the rotation of an object around a central axis * Spin (propaganda), an intentionally b ...

in a

magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to ...

will divide into magnetic sub-levels with an energy spacing.General Idea of Nuclear OrientationNuclear Orientation Group

University of Oxford , mottoeng = The Lord is my light , established = , endowment = £6.1 billion (including colleges) (2019) , budget = £2.145 billion (2019–20) , chancellor ...

, UK. The populations of these levels are determined by the

Boltzmann distribution In statistical mechanics and mathematics, a Boltzmann distribution (also called Gibbs distribution Translated by J.B. Sykes and M.J. Kearsley. See section 28) is a probability distribution or probability measure that gives the probability t ...

at a steady temperature and will essentially be equal. The exponential in the Boltzmann distribution should not be equal to 1 to obtain unequal populations. To achieve this, cooling to a temperature of around 10 millikelvin is needed. Typically, this is achieved by implanting the nuclei of interest into

ferromagnetic Ferromagnetism is a property of certain materials (such as iron) which results in a large observed magnetic permeability, and in many cases a large magnetic coercivity allowing the material to form a permanent magnet. Ferromagnetic materials ...

hosts. In the mid-1940s,

Yevgeny Zavoisky Yevgeny Konstantinovich Zavoisky (russian: Евгений Константинович Завойский; September 28, 1907 – October 9, 1976) was a Soviet physicist known for discovery of electron paramagnetic resonance in 1944. He likely obse ...

developed

electron paramagnetic resonance Electron paramagnetic resonance (EPR) or electron spin resonance (ESR) spectroscopy is a method for studying materials that have unpaired electrons. The basic concepts of EPR are analogous to those of nuclear magnetic resonance (NMR), but the spin ...

, eventually leading to the concept of nuclear orientation. In the early 1950s,

Neville Robinson Frank Neville Hosband Robinson (13 April 192519 October 1996) was an English physicist. Neville Robinson was educated at The Leys School in Cambridge, England, and Christ's College, Cambridge, where he read Physics. Robinson initially worked a ...

, Jim Daniels, and Michael Grace produced an example of nuclear orientation for the first time at the

Clarendon Laboratory The Clarendon Laboratory, located on Parks Road within the Science Area in Oxford, England (not to be confused with the Clarendon Building, also in Oxford), is part of the Department of Physics at Oxford University. It houses the atomic and ...

University of Oxford , mottoeng = The Lord is my light , established = , endowment = £6.1 billion (including colleges) (2019) , budget = £2.145 billion (2019–20) , chancellor ...

.Nicholas Kurti
Obituary: Neville Robinson
''

The Independent ''The Independent'' is a British online newspaper. It was established in 1986 as a national morning printed paper. Nicknamed the ''Indy'', it began as a broadsheet and changed to tabloid format in 2003. The last printed edition was publis ...

'', 27 November 1996. There is now a Nuclear Orientation Group at Oxford.

Bibliography

* K. S. Krane
Nuclear orientation and nuclear structure
''

Hyperfine Interactions In atomic physics, hyperfine structure is defined by small shifts in otherwise degenerate energy levels and the resulting splittings in those energy levels of atoms, molecules, and ions, due to electromagnetic multipole interaction between the nu ...

'', Volume 43, Numbers 1–4, pages 3–14, December, 1988. * B. Bleaney
Cross-relaxation and nuclear orientation in ytterbium vanadate
'' Proceedings: Mathematical, Physical and Engineering Sciences'', Volume 455, Number 1988, pages 2835–2839, 8 August 1999. Published by

The Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

. * B. Bleaney
Dynamic nuclear polarization and nuclear orientation in terbium vanadate
'' Applied Magnetic Resonance'', Volume 21, Number 1, pages 35–38, December, 1988.

References

{{reflist Nuclear physics Nuclear magnetic resonance

Bibliography

See also

References