haoliu
Hello,
I am wondering about how the peak intensity obtained from a single peak fitting is related to the raw data scale.
I fitted a peak in TOPAS, which returned an intensity ~1, but integration of the peak area from the raw data should give a value ~8. Obviously, there is a scaling factor involved in peak fitting. So does anyone know how to find out this factor?
The easiest way would be to work out the ratio between intensities obtained from the two methods, but I want to know if there is a built-in parameter in TOPAS that could tell me this straight away.
Thanks,
Hao
mfisch
Have you defined a LP_Factor? If yes, comment it out and try again.
haoliu
Yes, there was a LP_Factor, thanks.
alancoelho
If there were no back ground and you sum the raw intensities and multiply by the step size then you would get the integrated area. This area, in the absence of scale_pks, should equal the area parameter of the peak you are fitting. If you get stuck then send me your INP and data file
alan-jarvis
I understand that I can get the RAW area of a peak by summing peak intensities x step size.
How can one get the CALCULATED ("fitted") peak area?
alancoelho
>How can one get the CALCULATED ("fitted") peak area?
The I parameter is the integrated area. This area can be multiplied by scale_pks; see "6.2 Peak generation and peak types" in the Technical_Reference.PDF