GRaSP, for
Gamma Ray Attenuation Shielding Parameters, is a newly developed web-based code
to calculate a number of gamma-ray shielding parameters.
It calculates various gamma shielding parameters such as
mass attenuation coefficient (μm),
half-value layer (HVL),
tenth-value layer (TVL),
mean free path (MFP),
atomic cross section (σa),
electronic cross section (σe),
effective atomic number (ZEff), and
effective electron density (NEff),
based on the energy and mass attenuation data obtained from XCOM.
It is designed to be user-friendly and provides a simple interface
for users. Although the page to run the code is self-explonatory,
some detail are given below.
Selection of Material
GRASP can be used to calculate the gamma-ray shielding parameters
for elements, compounds and mixtures. For elements, the user is expected
to provide only the chemical symbol, H for hydrogen as an example. For compounds,
the chemical formula, for instance Bi2O3, should be given as input. Lastly,
for mixtures, the user have two options to enter the chemical formula; either in
mole or weight fraction. If "mole" is selected, the input can either
be in the form 70H2O + 20NaCl + 10HCl or 0.7H2O + 0.2NaCl + 0.1HCl. The program
require the coefficients of the compounds add up to 100 or 1, for the former and
latter, respectively. If the condition is satisfied, the program converts the
coefficients into corressponding weight fractions. If "weight" is selected, the
format for input should be in the form 0.45H2O + 0.4NaCl + 0.15HCl where coefficients
add up to 1.
Energy Range
The program produces the data for the parameters given above in the default energy
range the energy range between 1x10-3 and 105. However, if a narrower energy range is selected by
the user, then the output will be within the new limits.
Density of the Material
Since some of the parameters such as HVL and TVL
require density information, the user should provide it
if the exact values for such parameters are needed. If the density is
not given, the program gives the behavior of the parameter
as a function of energy using 1 g/cm3 as default, and
the user should make a correction if the exact value is.
Output
If the conditons for the coefficients mentioned above are satisfied,
the program prints the elemental weight fractions to the screen and
plots all selected parameters as a function of energy. Results are also given
in a table that can be downloaded.
Please refer to the following article for further information: