Typically, Brass is CuZn39Pb3. The technical data can be found in https://www.euralliage.com/cw614n.htm

Element	Cu	Pb	Zn	Density  g/cm3
Mini:	 57,0 	2,5 	40.5	8,4

In the materials properties, this material is defined as 100% copper as the nuclear cross section for Zn is not available in ICRU.
However, the stopping power were computed with the complete composition of Brass with the Berth formula.
The Radiation_Length is also computed with the complete composition of Brass. This should give a better estimation of the scattering compare to copper only.
