Here is some information to help calculate RADIATION LENGTH:
LENGTH(cm) * DENSITY(g/cm3)
RADIATION LENGTH = ----------------------------
X0(g/cm2)
========================================================
Matl
Z
A
Density (g/cm3)
X0 (g/cm2)
------------------------------------------------------------------------------------------------
15NH3 7/1
15/1
0.917 (0.917)
43.26 (43.25)
15ND3 7/1
15/2
1.056 (1.056)
50.50 (50.46)
6LiD 3/1
6/2
0.82 (0.82)
80.42 (76.18)
12C
6
12
2.265 (2.20)
42.66 (42.70)
9Be
4
9
1.85 (1.85)
65.19 (65.19)
27Al 13
26.98 2.70
(2.7)
24.01 (24.01)
64Cu 29
63.55
8.96
12.86
59Ni 28
58.69
8.76
12.68
LHe-4 2
4
0.145 (0.145)
94.32 (94.32)
He-gas 2
4
0.000178
94.32 (94.32)
air
0.00129
36.66 (36.66)
========================================================
*the () denotes values as given by Peter, although he claims some of
them
should be taken as only approximate values. The ones NOT in parentheses
are values I am presently using in my code, most of the X0 values were
calculated by ME using a SLAC parameterization.
http://www.slac.stanford.edu/exp/e155/home.html
(click "Polarized Target Information")