\author{
R.\ Coath$^a$,
D.\ Cussans$^b$,
J.\ P.\ Crooks$^a$,
P.\ D.\ Dauncey$^c$\thanks{Corresponding author},
R.\ Gao$^d$,
J.\ Goldstein$^b$,
A.-M.\ Magnan$^c$,
Y.\ Mikami$^e$\thanks{Current address: Institut Pluridisciplinaire Hubert CURIEN, 23 rue du loess - BP28, 67037 Strasbourg CEDEX 2, France.},
M.\ Noy$^c$\thanks{Current address: CERN, CH-1211 Gen\`eve 23, Switzerland.},
A.\ Nomerotski$^d$,
T.\ Price$^e$,
V.\ Rajovic$^e$\thanks{Current address: Faculty of Electrical Engineering, University of Belgrade, Bulevar kralja Aleksandra 73, 11120 Belgrade, Serbia.},
M.\ Stanitzki$^a$,
J.\ Strube$^a$,
R.\ Turchetta$^a$,
M.\ Tyndel$^a$,
J.\ J.\ Velthuis$^b$,
N.\ K.\ Watson$^e$,
J.\ A.\ Wilson$^e$,
Z.\ Zhang$^a$\\
\llap{$^a$}STFC,
Rutherford Appleton Laboratory,
Chilton, Didcot, UK.\\
\llap{$^b$}School of Physics,
University of Bristol,
Bristol, UK.\\
\llap{$^c$}Department of Physics,
Blackett Laboratory,
Imperial College London,
London, UK.\\
\llap{$^d$}Department of Physics,
University of Oxford,
Oxford, UK.\\
\llap{$^e$}School of Physics and Astronomy,
University of Birmingham,
Birmingham, UK.\\
\\
E-mail: \email{P.Dauncey@imperial.ac.uk}
}
