Website latest update on July 24, 2020

Welcome to the SR-NIEL Calculator Website. In these pages you can find information about the Screened Relativistic (SR) Calculator regarding Non-Ionizing Energy Loss of electrons, protons ions and neutrons passing through an absorber, generating displacement damages and, for instance in semiconductors, introducing deep levels resulting from the Frenkel pairs created. NIEL doses (also termed "displacement damage doses") are also provided. Furthermore, a calculator for the nuclear stopping powers of electrons, protons, light- and heavy-ions is available. The calculations are carried out based on the screened relativistic treatment for (elastic) Coulomb interactions on nuclei from low up to ultra-relativistic energies.

Users should be informed that, gradually, in addition to the treatment of displacement damage mechanisms resulting from non-ionizing energy losses (NIEL), the topics included in this website were extended to deal with the processes of electronic stopping powers, restricted energy losses, ionizing doses (TID) and effects due to large energy depositions in devices (i.e., SEE). In addition, currently one can directly access to the solar modulated spectra for cosmic rays species with Z up to 28 from HelMod model. These modulated spectra are derived by solving Parker’s equation (see here) when the local interstellar spectra (obtained from the GalProp-HelMod join effort) are transported through the heliosphere.

In the present website version, a calculator for the probability of generating energetic recoil nuclei is also available. From version 1.5.2, additionally, the estimates of recoil energy fractions deposited via ionizing and non-ionizing processes are accessible using two of the mostly employed analytical approximations of energy partition function.
From version 2.0 the electronic stopping power and ionizing dose calculator are also available.

From version 2.1 the current calculator allows one to obains NIEL  values and NIEL doses for neutrons in Si and GaAs absorbers, derived from ASTM-722-09 and ASTM-722-14 standards.

From version 3.0 registered users can access to SR-NIEL web calculators with additionally implemented Akkerman and Barak (2006) partition function; For information please contact This email address is being protected from spambots. You need JavaScript enabled to view it..

Currently, additional functionalities implemented into NIEL calculators for registered users are:

  • electron NIEL with Akkerman partition function;
  • proton and ion NIEL with Akkerman partition function;
  • NIEL dose calculators for neutrons and neutron spectral fluence in some elements (C, N, Si, Ga, As, from version 3.5.1 0, Al, P, In, Cd, Te, Ge, Zn, Se, Sb, from version 3.9 Cu, Hg, Pb, S, Sn, from version 3.9.2 B, Bi, Cl, Tl, from version 4.5.0 Li, Ti, Mn, Br, Sr, Nb, Mo, Ag, I, Ba, La, Eu, U and from version 4.6.0 also H, He, Be, F, Na, Mg, Ar, K, Ca, V, Cr, Fe, Co, Ni) and their compounds, using Robinson and Akkerman partition functions. The complete set of nuclei for neutron dose calculators was made avaible with version 5.0.0 and is illustrated at this page.
    Furthermore, a critical discussion on the usage of 1 MeV neutron equivalent is also available to registered users.

In addition, for registered users are available the following long write-ups:

  • NIEL for Electrons and Protons (with only Coulomb scattering and, also, including hadronic contribution) in Silicon employing Robinson and Akkerman partition functions;
  • NIEL dose calculation for neutron using Robinson and Akkerman partition functions;
  • comparison of Damage Functions obtained with Akkerman and Robinson Partition Functions for some compounds;
  • determination of the Damage Function at 1 MeV for Si and some compounds.

More pieces of information about sr-treatment are currently available from the website dedicated to the physics of displacement damage, due to neutron, proton, ion and electron interactions on nuclei.

At present, in the sr-niel website, calculators for ionizing energy losses (and doses) of electrons, protons and ions  are also available. In addition, from version 5.5 it is availabe a calculator to determine the residual spectral fluence for particles traversing a shielding material. The high energy extension of the electronic stopping powers of protons and ions is accessible with version 6.2.3.

From version 6.3.0, the web-calculators on electronic stopping powers – regarding the energy lost by particles traversing a medium – are complemented by those on restricted energy-losses to deal with both the energy deposited by incoming particles in absorbers and the approach to Fermi plateau at high energies. The topics on electronic stopping power and restricted energy-loss are treated in the physics handbook, which with version 6.4.2 is also enlarged by referring to those topics treated in related activities discussed within ASIF, HelMod and GeoMagSphere websites. From version 6.5.0, the occurrence probability of events due to a large energy deposition in devices - e.g., single event effects (SEE) - is also treated; while from version 6.6.0 galactic cosmic rays fluxes are available from HelMod model for being employed in sr-niel SEE calculator.

This project is part of the activities on going at the sr-niel/ASIF/AMS-02 Milano Bicocca group.

The implementation of SR-NIEL treatment and derived SR-NIEL calculators into ESA (European Space Agency) codes (e.g., SPENVIS, GRAS and Mulassis) is accomplished under ESA contract 4000116146/16/NL/HK with title "Non-Ionizing Energy Loss (NIEL) Calculation and Verification".

For any comment, remark and suggestion, please contact us by email This email address is being protected from spambots. You need JavaScript enabled to view it..