Add a second x-axis

Hi, in this plot:

I’ve on x-axis the number of secondary electromagnetic particles and on y-axis the number of secondary muons of cosmic rays showers. From left to right, the points correspond to bigger energy of the primary particles:

At first point I’ve a mean energy of primary particle 30,53 GeV
Second point 69,34 GeV
Third point 138.70 GeV
fourth point 260.98 GeV
fifth point 453.25 GeV
sixth point 765.59 GeV

so I’d like to show not only the number of the secondary particles, but the energy of the primary particles, so I’d like to add one second x-axis where there is the primary particles energy…something like this plot:

where there is a second x-axis (red color), is it possible?
In the attachment the macro used.
distribuzioni-emmu.txt (226 Bytes)
distribuzioni-emmu.txt (246 Bytes)
hnenmumed2.c (1.94 KB)

x-coordinates of the points (“N_{e.m.}”) in the two drawn graphs are completely different (so, you cannot add a common axis which transforms the “point number” into “primary energy”).

Hi pepe and if I add 2 x-axis one for primary gamma and one for primary proton (for example in the up of the plot to add the x-axis energy for the primary protons and in the bottom for the gamma primary)? is it possible in this way?

Maybe you can live with this.
hnenmumed2.cxx (3.03 KB)

Hi pepe thanks! it’s perfect!