(Chair: Lorenzo Natalucci).
It aims at the cross-calibration analysis of G21.5-0.9 (mainly below 10 keV) and of the Crab (mainly above 10 keV) spectra.
Current members: A.Beardmore, G.Cusumano, L.David, M.Guainazzi, J.Kaastra, M.Ishida, K.Jahoda, E,Jourdain, Y.Maeda, A.Read, R.Rothschild, T.Sakamoto.