2.3 Calibrating and Fitting Spectra (using the BSC software)


next up previous contents
Next: 2.3.1 Listing the BSC Up: 2 Bragg Crystal Spectrometer Previous: 2.2.8 Light Curves of

2.3 Calibrating and Fitting Spectra (using the BSC software)

     

BCS data that have had instrumental corrections and calibrations applied to them are referred to as BSC data. BSC stands for BCS Spectrally Calibrated data which has had crystal curvature corrections applied and has been converted to photons cm s. For quantitative work with BCS spectra the user should always begin by constructing the BSC data structures from the raw data files. This IDL-based software replaces that FORTRAN code that was previously used (see the section on BSD Analysis Software); hopefully this will eliminate some of the difficulties encountered in the installation of the FORTRAN code on the various Unix and VMS platforms. The routines are outlined here, but more information can be found in the BCS part of the reference manual.

0.1 in The routines work with structures that are compatible with all the other instrument structures in the Yohkoh database. An outline structure (the BSA structure) containing a specification of what data are to be extracted from the BDA file is first created by MK_BSA, and then the BSC structure (and optionally a BSC file) is assembled by the routine MK_BSC.

First run YODAT to extract the index and data arrays from the BDA file for the selected time interval. Make sure to ask for the DP_SYNC data. The routine MK_BSC is then called as follows:
IDL> mk_bsc,index,data,bsc_index,bsc_data,dp_sync=dp_sync
 
IDL> mk_bsc,index,data,dp_sync=dp_sync,/file
The second case will write the corrected data to a BSC file. The following routines are used in the assembly of the BSC file:

    BCS_ACCUM     accumulates BDA data into a BSC structure.
    BSC_XCORR     applies curvature corrections to BSC data.
    BSC_FLUXCAL   applies flux calibrations to BSC data.
    BSC_ERRCAL    computes uncertainties for the BSC count spectra.

If the /file option is not used when calling MK_BSC, a BSC file may be written using SAV_BSC. An existing BSC file may be read in with RD_BSC and, after modification, again a new file may be written with SAV_BSC - see the Reference Manual for more details.



next up previous contents
Next: 2.3.1 Listing the BSC Up: 2 Bragg Crystal Spectrometer Previous: 2.2.8 Light Curves of


ydac@mssly1.mssl.ucl.ac.uk