Regensburg 2013 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 42: New Instruments and Methods
CPP 42.1: Talk
Thursday, March 14, 2013, 11:30–11:45, H39
Design of neutron spin-echo spectrometers for ESS — •Stefano Pasini1, Michael Monkenbusch1, and Melissa Sharp2 — 1Jülich Center for Neutron Science, FZJ, Germany — 2ESS AB, Lund, Sweden
Neutron spin echo (NSE) is the technique with the highest energy resolution for probing the dynamics of materials. Within the German European Spallation Source design update project, the Research Centre Jülich is optimizing a high-resolution (HRNSE) and a wide-angle neutron spin-echo (WANSE) spectrometer. The specifications of the polarization system will be analogous for both instruments: A straight, 8cmx8cm neutron guide with a comparatively short (~2.6m) polarizing bender or eventually a single polarizing mirror inducing a kink in the guide. A potential beam extension and focusing in horizontal direction for the WANSE is still under investigation. For the design of the magnetic layout of the HRNSE, we combined the active stray field compensation techniques used at the SNS-NSE, enabled by superconducting coils, and a coil-geometry optimization versus minimization of field-integral inhomogeneity, depolarization and stray-field. We found a solution with 3 times reduced intrinsic inhomogeneity of field integrals and low stray fields allowing for a working configuration up to 2Tm field integral. The limitations of the correction elements will be partly resolved by the increased field homogeneity. The strategy of low intrinsic inhomogeneity has been pursued also for the WANSE. This should allow us to reach a resolution comparable with that of the current high resolution J-NSE@FRM-II.