Time-of-Flight Neutron Diffraction for Long Pulse Neutron Sources

Abstract

The Time-of-Flight (TOF) method for neutron diffraction was proposed half a century ago by Buras and Leciejewicz [1] as a very efficient alternative to the crystal monochromator technique most often used at that time. It was the advent of the first pulsed spallation sources that has shown how farsighted this proposal was– the diffractometers naturally based on the TOF method have become most productive powerhouses at these sources. High performance in diffraction is a most basic goal and requirement for all neutron sources now or in the future and a technique to achieve this is of central importance for the new generation of long pulse sources pioneered by ESS. The central challenge for such a technique is to produce short pulsed white neutron beams from the long pulses in order to meet all resolution requirements in diffraction. No efficient method for such pulse shaping could be successfully developed at the short pulse sources. In the second half of the 1990s, in collaboration with HZB (then HMI), the Budapest Neutron Center (BNC) undertook the development of powerful TOF diffraction for both its own use and with the perspective of establishing at a continuous source the foundations of TOF diffraction techniques for future long pulse sources.