1. STFC ISIS Pulsed Spallation Neutron and Muon Facility, Rutherford Appleton Laboratory, Harwell OX11 0QX, United Kingdom
2. Department of Physics, University of Jyväskylä, 40500 Jyväskylä, Finland
3. Zepler Institute for Photonics and Nanoelectronics, University of Southampton, Southampton SO17 1BJ, United Kingdom