Before Suzaku FTOOLS Version 7, the tool "mk_corweighted_bgd_v1.1.pl" and the data set of night Earth released from the XIS team were used to estimate the non X-ray background (NXB).
At Suzaku FTOOLS Version 7, which was a part of HEAsoft Version 6.4 released in December, 2007, the tool was upgraded to "xisnxbgen" and was released as one of the official FTOOLS. The NXB database was released as a part of the official Suzaku CALDB.
Now users should use "xisnxbgen" with the Suzaku CALDB instead of "mk_corweighted_bgd_v1.1.pl" to estimate the NXB. The tool "mk_corweighted_bgd_v1.1.pl" is now obsolete. The FTOOLS help document and the Suzaku ABC guide give detailed information about "xisnxbgen".
If you have a problem, please contact Suzaku Help Desk.