Experiments with subatomic particles don’t often have to account for gravitational potential energy. A proton or neutron moving through Earth’s gravitational field gains or loses just 100 neV for every meter of altitude change. For many purposes, that’s an insignificant amount.

But a new proof-of-concept neutron backscattering spectrometer is so sensitive to tiny changes in energy that gravitational effects matter.1 The spectrometer (whose vertical scale is shown in figure 1) is located at Institut Laue–Langevin in Grenoble, France, and was devised and developed by a team led by ILL scientist Bernhard Frick and Andreas Magerl of Friedrich–Alexander University of Erlangen–Nuremberg in Germany. Its energy resolution, 78 neV, is an order of magnitude better than a typical instrument of its type and a factor of four better than the best currently available.

Neutron backscattering spectroscopy is used to measure the minute energy shifts in neutrons that scatter off a...

You do not currently have access to this content.