The program uses a detector matrix file, default XRTCAL:DRMPSPC, to calculate the basic response. To convert this response into an effective area the response from the matrix is multiplied by the energy dependent correction array written into the datafile by XRTCORR. The corrections program should have written an array MORE.ASTERIX.INSTRUMENT.ENCORR(n).DATA_ARRAY into the datafile. If this isn't found then the program will exit with a message to that effect.