#name   Format    Air; 78 % N, 21 % O  1 % Ar
Air50 	2
#   treated as 0.78N2+ 0.21O2+ Ar 
#  Elem	 rho(g/cm^3)	Gas/Solid(1/0) refl.index               Birks corr.
#                                     (for gas, (n-1)*10^6)

3         7.372672e-04		  1    293                       0  0  0
# 	Z	A  	N
	7	14	1.56
	8	16	.42
	18	40	.01
#  <Z/A>  I[eV]   a       k      x0    x1     Cbar  delta0
 0.49919   85.7  0.1091  3.3994  1.7418  4.2759  10.5961 0.00
