Input and output

• An ASTERIX binned dataset, containing data taken within a box centred on the source.
• A binned dataset containing data taken from a background box
• Cal files: The effective area file and detector response file are needed. The default at the prompt line will be the standard files which are contained in the XRT calibration data directory.
• If particle rates are being calculated, the program needs the header file and the eventrate file.

If requested, an HDS file containing the calculated background in the source box (i.e. source file - subtracted file) may be produced.