The current web calculator for collision electronic stopping power is based on a fit of the tables - based on ICRU Report 37 - from EStar code at NIST.
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 Electronic Stopping Power and Dose for Electrons:
How to use this Electronic Stopping Power Calculatorand Ionizing Dose Converter
This tool calculates the Electronic Stopping Power curve for a particle incident on a 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.
This web calculator has been complemented by an ionizing dose converter which allows one a quick estimate of the ionizing dose absorbed by a materiel or a compounds. However, for the conversion from electronic stopping power to dose, the energy lost by the incoming electron is assumed to be fully absorbed by the medium - i.e., it is supposed to to be thick enough to fully absorb the kinetic energy of emitted delta rays - and the electron energy is almost constant while the particle traverses the absorber. In addition, radiative phenomema are assumed to be negligible - as, for instance, when the electron energy is well below that critical - e.g., see for a definition and a discussion Sect. 126.96.36.199 in Leroy and Rancoita (2016) and references therein -, and subsequent interactions of emitted photons are not taken into account. The discussion on the relevance of ionization energy loss (e.g, see Sects. 2.1-188.8.131.52 in Leroy and Rancoita (2016) and references therein) with respect to radiative emission of electrons can be found, for instance, in Sects. 3.1-184.108.40.206 and 3.2 of Leroy and Rancoita (2016) and references therein.
- Target material (Single Element or Compound)
- Calculator energy limits.
- Particle fluence for dose calculation.
In the section "Target Selection" it is possible to specify a 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):
The overall max difference for compounds is 0.36% and the average difference is 0.17%.
This section define the energy limits of the calculation, and the following parameters will be defined:
- Minimum Energy of the incident particle
- Maximum Energy of the incident particle
The output table will contain 20 fixed values for each decade within the above selected range.
Moreover a text box is provided for entering additional energies. The input format is one energy per line; it is also possible to copy and paste energy values.
Particle Fluence for Dose Calculation
Here has to be inserted the particle fluence to be used to obtain the corresponding deposited Dose.
The result page contains the input parameters, the Electronic Stopping Power curve and the result table, which includes the Ionizing Dose (in [MeV g-1] and [Gy]).
The upper energy limit of the ionizing dose converter is set to that of the critical energy in the medium. It has to be remarked that critical energy vales are those available from particle data group (PDG) 2018 web page on Nuclear properties. These values - based on the remarks available at the critical energy webpage in PDG web site - are expected to differ from the actual ones by a few percents.