Nuclear and Particle

GRASP-X README

GRASP-X, for Gamma Ray Attenuation & Shielding Parameters-eXtended, 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 (μ_m),
half-value layer (HVL),
tenth-value layer (TVL),
mean free path (MFP),
atomic cross section (σ_a),
electronic cross section (σ_e),
effective atomic number (Z_Eff), and
effective electron density (N_Eff),

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. The above-mentioned parameters are calculated for a chemical composition given either in mole percent or weight fraction, over the energy range from 1×10⁻³ to 10⁵ MeV. If no minimum or maximum energies are specified, the program uses the default energy range.

At an absorption edge, the program uses the tabulated mass attenuation coefficient (MAC) for the element that actually exhibits the edge. For all other elements in the mixture—whose attenuation coefficients remain continuous at that energy—the MAC at the edge is estimated using a log–log (power-law) interpolation. The interpolation is performed using two nearby XCOM tabulated points for energies between 1 and 1.5 keV, and three nearby points at higher energies. This approach ensures a smooth and physically consistent MAC estimate for elements that do not exhibit an absorption edge at the selected energy.

Since some parameters, such as HVL and TVL, require density information, the user must provide a non-zero density value (in g/cm³). If the density is omitted or given as zero, the program will generate an error and stop execution. If a non-zero value is supplied but does not correspond to the true density of the material, GRASP-X will compute the relevant parameters using the provided value, and the user should adjust it if exact results are required. The results are displayed both as a graph and a downloadable table.

Please cite the following article if you have used GRASP-X in your research:

M. Bektasoglu, I. Karnik, M. Ali Mohammad, "Investigation of gamma shielding parameters of some silica borotellurite glasses with different amount of Bi₂O₂ at energies between 10 and 150 keV", Radiat. Phys. Chem., 207, 2023, 110855
https://doi.org/10.1016/j.radphyschem.2023.110855.

Last Update: Dec 20, 2025.

• Revised MAC interpolation approach: exponential fitting replaced by power-law (log–log) interpolation to better reflect XCOM data trends.

Contact: Mehmet Bektasoglu (mehmetb@sakarya.edu.tr)