In 1998, a prototype of a time-of-flight (TOF) powder diffractometer was built at KFKI in Budapest in collaboration with the Hahn-Meitner-Institut (HMI) in Berlin. At a reactor source the neutron pulses are produced by a chopper system, which allows for shorter pulses than those obtained at pulsed spallation sources in the wavelength range most relevant for diffraction work, i.e. λ≥0.7 Å. Furthermore, the chopper system provides an ideal symmetric line shape. First results proved the high potential of the approach, namely an excellent resolution of 1-5×10-3 for Δd/d was achieved. The prototype is presently rebuilt as a user instrument at the Budapest Neutron Centre. At HMI Berlin a new much more complex TOF powder diffractometer (EXED=extreme environment diffractometer) with higher resolution is under construction. It will benefit from variable resolution to achieve either ultrahigh resolution or very high intensities at conventional resolutions. EXED is devoted to studies under extreme sample conditions, for instance the TOF technique permits the access of a broad range of Q-values or d-spacing domains under scattering angle access strongly restricted by the use of highest field magnets. The whole instrument was simulated by Monte Carlo (MC) technique, and the simulations yield promising results.
- Reactor source
- Time of flight
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering