X-ray surface brightness (left column) and temperature profiles (right column) for the sample of eight relaxed galaxy clusters. The black points are derived from the X-ray image and spectroscopic data. The blue lines in both profiles show the best fit model to the data obtained using a uniform Anders & Grevesse (1989) helium abundance, and the red lines show the best fit model obtained using the Peng & Nagai (2009) helium sedimentation distribution; the green lines in surface brightness profiles indicate the background levels determined from the blank sky observations. The overall χ² of the fits obtained from the uniform helium abundance and the helium sedimentation model (Tables 2 and 3) show that both distributions give equally good fits to Chandra data.