What is the real meaning of parameter a,b,c from DetGeb card?

i want to use DetGeb card for gauss broadening, but i do not know the real meaning of parameter a,b,c,
what is the function between FWHM and parameter a,b,c?

Dear Siyuan,

the equation between FWHM and the a, b, c parameters can be found in the DETGEB section of the FLUKA manual: 7.22.15. DETGEB — FLUKA Manual


@ Dávid Horváthhorvathd, thanks!