Wavelength frame multiplication for reflectometry at long-pulse neutron sources

Abstract

The European Spallation Source (ESS), which is under construction in Lund (Sweden), will be the next leading neutron facility with an unprecedented brilliance and novel long-pulse time structure. A long-pulse source not only provides a high time-average flux but also opens the possibility to tune the resolution by using pulse shaping choppers. Thus, an instrument can readily be operated in either a high flux or a high resolution mode. Several of the shorter instruments at the ESS will employ Wavelength Frame Multiplication (WFM) in order to enable a sufficient resolution while offering a continuous and broad wavelength range. A test beamline was operated until the end of 2019 at the research reactor in Berlin to test components and methods, including WFM, in order to prepare the new facility for the operation of neutron instruments and successful first science. We herein demonstrate the implementation of WFM for reflectometry. By selecting a short pulse mode under the same geometrical configuration, we compare and discuss the results for two reference samples. The reported experiments not only serve to prove the reliability of the WFM approach but also, for the first time, demonstrate the full instrument control, data acquisition and data reduction chain that will be implemented at the ESS.

Flexible Sample Environments for the Investigation of Soft Matter at the European Spallation Source: Part III—The Macroscopic Foam Cell

“…The EPICS is used by the Networked Instrument Control System (NICOS) [36], which offers a graphical interface for users and is the outermost layer of the instrument control structure at the ESS. Further details regarding instrument control and data streaming are described elsewhere [37].…”

Evaluation of a method for time-of-flight, wavelength and neutron flight path calibration for neutron scattering instruments by means of a mini-chopper and standard neutron monitors

“…The method was evaluated at the V20 beamline [10,11], a dedicated ESS test beamline at Helmholtz Zentrum Berlin (HZB), and utilized a high-frequency mini-chopper together with a BM, which was placed at two different positions. Between 2015 and 2019, the European Spallation Source operated the V20 test beamline, at the 10 MW research reactor of HZB, which was utilized for the testing of choppers [12], detectors [13] and other diverse topics [5,14].…”