The "Add" box contains the number of counts
to be added
to each pixel when the file is opened. The default is zero. Most
commonly
for background subtraction it is likely to be a small negative integer (i.e, you are actually subtracting the
same number of counts from each pixel).
Order of Operations: First, the contents of the Add box are added to each pixel in a given file. Then, each pixel is multiplied by the Mult box contents. Finally, the pixels in all the files are added together. Thus, if you had a data file A.raw which was counted for half as long as a background file B.raw, you might set the Add values for both files to be zero, the Mult value for A.raw to be 2, and the Mult value for B.raw to -1. |