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 th ...

, is the directional ordering of an assembly of

nuclear spin 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 * ...

s 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 Nuclide, nucleus to probe material properties. By Radiation emission, emission or Absorption (electromagnetic radiation), absorption of radiation from the nucleus ...

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: * Spin (physics) or particle spin, a fundamental property of elementary particles * Spin quantum number, a number which defines the value of a particle's spin * Spinning (textiles), the creation of yarn or thr ...

in a

magnetic field A magnetic field (sometimes called B-field) is a physical 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 ...

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

University of Oxford The University of Oxford is a collegiate university, collegiate research university in Oxford, England. There is evidence of teaching as early as 1096, making it the oldest university in the English-speaking world and the List of oldest un ...

, 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 tha ...

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) that results in a significant, observable magnetic permeability, and in many cases, a significant magnetic coercivity, allowing the material to form a permanent magnet. Ferromagne ...

hosts. In the mid-1940s,

Yevgeny Zavoisky Yevgeny Konstantinovich Zavoisky (; September 28, 1907 – October 9, 1976) was a Soviet physicist known for discovery of electron paramagnetic resonance in 1944. He likely observed nuclear magnetic resonance in 1941, well before Felix Bloch and E ...

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, 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 la ...

.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'', 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, r ...

. * 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