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A Neutron spin-echo (NSE) spectrometer of the next generation is under construction at the Spallation Neutron Source (SNS) in Oak Ridge, USA. A NSE spectrometer measures small velocity changes of the neutrons encoded by the neutrons spin clock at a sample while the Neutron spin precesses in large magnetic fields following Bloch's equation. This instrument will be the best of its class both with respect to resolution and dynamic range. In order to reach this ambitious goal, a large magnetic precision field integral before and after the sample is required which directly scales linearly with the resolution of the instrument. Therefore superconducting technology will be used to allow for a higher magnetic field integral. Here, we present the design, manufacturing and test performance of the solenoids which are the result of a collaboration between jülich Research Center (FZJ) and Babcock Noell GmbH (BNG). The solenoids generate an integrated magnetic flux density of 1.8 Tªm and use active shielding to reduce the fringe field. The operation temperature of about 4 K is reached by means of pulse-tube coolers in order to minimize vibrations. A special feature of this magnet system is the very accurate measurement of the cold mass-position after cool-down and during operation. The accuracy of this measurement system is in the order of micrometers. This information is required for the adjustment of so called Fresnel coils outside the cryostat. Using these correction elements, a field integral homogeneity better than 10-6 Tªm for different Neutron paths through one of the solenoids can be achieved. [ABSTRACT FROM AUTHOR]

The article reports on the inauguration of the neutron spin echo (NSE) spectrometer at the Spallation Neutron Sources (SNS) in Oak Ridge National Laboratory on November 5, 2009. The instrument, built by scientists and engineers at the Forschungszentrum Jülich, was funded by the German Federal Ministry of Education and Research and the Ministry of Innovation, Science, Research and Technology of North Rhine-Westphalia. The features and uses of the NSE spectrometer are detailed.

Thermal fluctuations in soft matter systems take place on length- and time scales of nanometers and nanoseconds, accessible with neutron spin echo (NSE) spectroscopy. New developments in instrumentation as well as data treatment opened the door for new measurements with highest precision for subtle effects and gains in energy resolution. Superconducting main coils with optimized field shape have been installed at the J-NSE recently, providing better resolution and more flux for a given resolution. The magnetic shielding of the SNS-NSE provides unprecedented phase stability, which has been exploited to study tiniest effects of additives to membrane fluctuations in microemulsions. New software for data evaluation, DrSPINE provides the intermediate scattering function in an easy and robust way. Scientific highlights and trends in NSE spectroscopy will be discussed. [ABSTRACT FROM AUTHOR]