Scientific Reviews: High-Resolution Fourier Diffraction at the IBR-2 Reactor

Abstract

High-resolution time-of-flight (TOF) diffractometers at short-pulse spallation neutron sources (SPS)—the most well-known example is HRPD at ISIS—have proved themselves to be extremely good for various applications. The resolution, R = Δd/d, close to 0.001 or even a bit better, can be easily obtained if a flight path amounts to 50-100 meters. But at so-called “long pulse sources” (LPS), with the pulse width Δt ₀ equal to hundreds of microseconds, the flight path would need to be too long if a 0.001 resolution level is required. In this case, effective shortening of the neutron pulse should be done by employing a counter-rotating pair of fast disc choppers (see, for instance, Ref. [1]) or the correlation Fourier technique.

Acknowledgments

All the work discussed in this paper is the result of the efforts of the many people at FLNP (Dubna), PNPI (Gatchina), MSU (Moscow), “Kurchatov Institute” (Moscow), VTT (Espoo, Finland), and IzfP (Dresden, Germany) named in the references. The work was partially financed under a JINR-BMBF (Germany) agreement.