XMM-Newton EPIC in orbit background
  We briefly describe the methods used in compiling a set of high galactic latitude background data. The characteristics and limitations of the data which affect their use as a template for analysing extended objects are described. We briefly describe a spectral fitting analysis of the data which reveals a normalisation for the extragalactic background of 11.4 keV / sq cm / s / sr, which implies the fraction of hard X-ray background presently resolved by various Chandra observations is towards the lower limit of their estimates. 
D. H. Lumb