Why study muons

Some links may take you there. If you can't find what you're looking for, try ukri. Muons are used to study materials at the atom level. They are often used alongside neutrons to provide detailed information on atomic-level properties.

ISIS is one of only four places in the world where it is possible to use muons for materials studies. But corrections added to more advanced theory owing to the effects of short-lived virtual particles increase g by about 0. In —, the Brookhaven collaboration measured this quantity using a 15 m-diameter storage ring fitted with superconducting magnets that provide a vertical 1.

Because the positrons have more energy on average when the spin aligns in a forward direction, the intensity of the most energetic positrons registered by the detectors varies cyclically — dropping to a minimum after about It is this frequency — the number of such cycles per second — that reveals the precise value of a.

That discrepancy then rose as theorists refined their Standard Model predictions, so that it currently stands at about 3. The latest measurements extend the disparity still further. The recent measurements were made using the same storage ring as in the earlier work — the tonne apparatus was transported in over km via land, sea and river from Brookhaven near New York City to Fermilab on the outskirts of Chicago.

But while the core of the device remains unchanged, the uniformity of the magnetic field that it produces has been increased by a faxtor of 2. The international collaboration at Fermilab has so far analyzed the results from one experimental run, carried out in Describing its results in Physical Review Letters , alongside more technical details in three other journals, the collaboration reports a new value for a of 0.

On its own, this is 3. Together, the results from the two labs yield a weighted average of 0. But he argues that it is still too early to completely rule out systematic errors as the cause of the disparity, given that the experiments at both labs have used the same muon storage ring. This, he maintains, raises the importance of a rival g—2 experiment under construction at the Japan Proton Accelerator Research Complex in Tokai.

For the case of superconductors, as well as being able to explore atomic-level magnetism associated with superconductivity, muons provide an important probe of flux lattice behaviour, and can give information complementary to small angle neutron scattering.

There are other reasons why muons may be the best technique to use for a given sample. For example, the muon method can be used in zero applied field, whereas NMR would require application of fields which may affect sample properties. In cases where the behaviour of the muon itself is of interest, such as when using muons as proton analogues to study hydrogen behaviour, undoped, intrinsic samples can be used.

Characteristics of neutrons Grand Challenges Scientific disciplines Techniques for News and media News from NMI3 and the neutron and muon worlds. Science Google Search Search. What can be studied with Muons?

Muon science Muons can be used to explore a very diverse range of materials. Applications Muon Spin Rotation and Relaxation are mostly performed with positive muons.