  XMM-Newton, with its high throughput and excellent spatial and spectral
resolution, is an ideal instrument for spectro-imaging observation of clusters.
Presented here is an XMM-Newton mosaic observation of A2163, from which a new
radial temperature profile is derived. The issue of background subtraction is
addressed in some detail as a proper treatment of the background is essential
for the derivation of correct temperatures, and thus, of the correct total
cluster mass.
