Cookie Policy

Welcome to SR-NIEL. This site uses cookies. Read our policy.

Logo HelMod small


Screened Relativistic (SR) Treatment for NIEL Dose

Nuclear and Electronic Stopping Power Calculator

(version 8.0)

Proton High AMS02 small

The current web calculator allows one to obtain the residual spectral fluence or residual energy for electrons a shielding material by exploiting the collision electronic stopping power (based on a fit of the tables - based on ICRU Report 37 - from ESTAR code at NIST) and the radiative stopping powers (those evaluated in ESTAR - e.g., see webpage). The fitting function is a polynomial of degree 15 and the tables are reproduced with a maximum discrepancy < 1%.

The following link give access to the Web Applications for the calculation of the residual spectral fluence or residual energy for electrons traversing an absorber:

- Web Calculator for residual spectral fluence or residual energy of electrons traversing an absorber


How to use this Calculator for particle spectral fluences or mono-energetic particles traversing an absorber

For an incoming particle spectral fluence or mono-energetic particles, this tool allows one to calculate the residual spectral fluence or residual energy after traversing a shielding material.


The input parameters and options for the tool are described below. When the input form has been completed, pressing the "CALCULATE" button will start the calculation and open the "Results" page (allow for pop-up in your browser settings). The result page will be also linked at the bottom of the calculator page.


Input Parameters:

- Input type
- Target material (Single Element or Compound)
- Traversed path
- Number of steps
- Particle spectral fluence.

Input type

In the web Calculator, using the pull down menu, the user can select the calculation of the residual spectral fluence or the residual energy for incoming electrons.  

Target Material

In the section "Target Selection" it is possible to specify Single Element target material or a predefined Compound material.

Following is the maximum difference percentage between the fit and ICRU tables for single elements as a functions of the target atomic number (Z):

ICRU Diff Element

The overall max difference for compounds is 0.36% for collision, 0.91% for radiative. The average difference is 0.17% for collision and 0.73% for radiative.


Traversed Path

This input define the traversed path by a particle fluence. The traversed path is expressed in [g cm-2] ad is given by:

(absorber thickness in cm) x (absorber density in g cm-3) .


Number of Steps

In the web Calculator, using the pull down menu, the user can select the number of steps of the calculation - i.e., the traversed path is divided by the number of the steps.
The results of each steps is used as input for the following one to obtain the final result for the total traversed path.

The minimum traversed path allowed for each step is 100 μm of Si (2.3x10-2 [g cm-2]).


Particle Spectral Fluence

This section define the points of the spectral fluence as a function of energy.
The input format is one point per line (Energy - Flux , separated by a space or tab); it is also possible to copy and paste values. The minimum value of the particle spectral fluence is 1 keV.


Mono-Energetic Particle

This section define the list of energy of the incoming electrons.
The input format is one energy per line; it is also possible to copy and paste values. The minimum value of the particle energy is 1 keV.



The result page contains the graph of the input spectral fluence and the spectral fluence after traversing the absorber. The table provides the values of the spectral fluence (above 1 keV) and the residual spectral fluence (above 1 keV) after traversing the absorber. In addition, the incoming and residual spectral fluences are provided. In case of mono-energetic particles a table with the incoming energy and residual energy is provided.