  We employ a long XMM-Newton observation of the core of the Perseus cluster to
validate claims of a non-thermal component discovered with Chandra. From a
meticulous analysis of our dataset, which includes a detailed treatment of
systematic errors, we find the 2-10 keV surface brightness of the non-thermal
component to be smaller than about 5x10^-16 erg cm^-2s^-1arcsec^-2. The most
likely explanation for the discrepancy between the XMM-Newton and Chandra
estimates is a problem in the effective area calibration of the latter. Our
EPIC based magnetic field lower limits are not in disagreement with Faraday
rotation measure estimates on a few cool cores and with a minimum energy
estimate on Perseus. In the not too distant future Simbol-X may allow detection
of non-thermal components with intensities more than 10 times smaller than
those that can be measured with EPIC; nonetheless even the exquisite
sensitivity within reach for Simbol-X might be insufficient to detect the IC
emission from Perseus.
