This specific command is used to remove the particle background of the ROSAT PSPC from CORRECTED spectra (i.e. from spectra produced via Projection set in correction mode), before using PREPARE/SPECTRUM. The particle background is modeled according to [Plucinski et al.1993] This model is not valid for Master Veto rates higher than 170 counts, and for amplitude channels not included in the interval 18-249.
The computed particle spectrum, normalized to the source+back spectrum - i.e. corresponding to the same exposure time and sky area) is always written to the table parbak.tbl just for check purposes (this file is not necessary in the next analysis). The particle spectrum is removed automatically from the CORRECTED spectra in the input table(s). The original corrected spectra are saved in any case to a new pair of this table(s) columns.
Please notice: the PSPC particle background is surely negligible in most cases. The correction is so small that it makes no sense to apply it to noisy spectra. Only when very extended objects are involved (as for instance when large portion of the sky are taken to sample the total background spectrum), then the particle background becomes relatively important.
The following sequence of commands shows how and where the REMOVE/PARTICLE command might be applied within the task of creating a corrected and background subtracted spectrum.
Midas 001> SET/PROJECTION CORRECT Midas 002> SELECT/RING [0,0,100][0,0,150,250] BIN AMP 1,18,249 *events *table Midas 003> REMOVE/PARTIC table Midas 004> PREPARE/SPECTRUM table