Need Help Determining Flatness in ROOT (ProjectionX)

___Hi everyone,

I have a cumulative dose curve for XY and YZ, and I want to determine the flatness for just the first millimeter. I need to fix the Y-axis to measure the flatness in just the first millimeter, but I don’t know how to do it in ROOT (ProjectionX).
thank u for your helping in Advanced !

ROOT Version: 6.24
Platform: Ubuntu Linux
Compiler: Not Provided

Welcome back @Soufiyan-Yachou! I think we need a bit more info to answer this question.

How do you store these curves? In a TGraph? And what do you mathematically mean by “flatness”?

Hi Jonas,

Thank you. It’s in the form of a histogram. The “flatness of dose” refers to the distribution of dose along the x, y, and z axes. Mathematically, it is represented as:
Flatness Beam = 100 x (Dmax-Dmin)/Dmax+Dmin.