Snyder Head wTumor Directory README.   September 30, 2005
This MCNP file is an adaption of the Snyder Head Phantom geometry.
It contains a layer of scalp and an explitic 2.54 cm radius tumor.  
The tumor contains 30 ppm Boron-10, a strong neutron absorber.
The radiaiton source is an epithermal neutron beam, 
with 1% fast (10 keV to 2 MeV), 89% epithermal and
10% thermal (1meV to 0.5 eV) neutrons.

More about this input deck geometry, neutron source, and kerma calculations
can be found in:
Goorley T, Kiger WS III, Zamenhof RG. Reference Dosimetry Calculations 
for Neutron Capture Therapy with Comparison of Analytical and Voxel Models. 
Med. Phys. 29 (2) 2002. pp. 145-156.