A monochromatic X-ray backlighter based on Bragg reflection from a spherically bent quartz
crystal has been developed for the MAGPIE pulsed power generator at Imperial College (1.4 MA,
240 ns) [I. H. Mitchell et al., Rev. Sci. Instrum. 67, 1533 (2005)]. This instrument has been used
to diagnose high energy density physics experiments with 1.865 keV radiation (Silicon He-α) from
a laser plasma source driven by a ∼7 J, 1 ns pulse from the Cerberus laser. The design of the
diagnostic, its characterisation and performance, and initial results in which the instrument was used
to radiograph a shock physics experiment on MAGPIE are discussed.