Differential intensity integrated over the mission duration and forecast.

This site provides access to the main HelMod web calcultor - which is an application of the latest available HelMod Code - for unregistered users, e.g.,

HelMod data sets and results can be freely downloaded or copied. However, we strongly suggest user to provide an appropriate acknowledgment and/or citation, e.g., see  Citations or Bibliography  pages.

How to use this HelMod Calculator

This tools evaluates the modulated spectrum at Earth orbit for theorical LIS evaluated with GALPROP. The particle transport is described using the Helmod Model. For information about the computation method please refear to Monte Carlo Integration page.

The input parameters and options for the tool are described below. Once the input form has been completed,  "Submit" button will start the calculation and open the "Results" page (allow for pop-up in your browser settings).


Solar Modulation Model

The website is always updated with the latest HelMod version available, as indicated in the output result.
Previous version remains available for a limited period during updating.

Expected Mission Duration/ Past Missions

User can select either the time interval for the interested simulation or refer to a standard published dataset (e.g., AMS-02).

  • Expected mission  duration: allow to select a single Galactic Cosmic rays species and the expected duration of the mission. By default the module evalute the modulated spectrum for a single Carrington rotation containing the "begin of the mission" value. To evaluate the average modualted spectra over the entire period of the mission, check the box "Average over the entire period" and select the date of the end of the mission.
  • Past missions: allow to compute modulated spectra referring to period and GCR species described in  standard published datasets. User may select, in order, the Experiment (e.g. AMS-02), then the GCR species (e.g. Proton) and finally the publised dataset.

Display Options

  • x-axis value: Select if output result should be computed in Particle Rigidity [GV] or in Kinetic Energy per nucleon [GeV]. If "auto" is selected, the system will choise the best one for the selected dataset.
  • Addittional modulation models: compute the modulated spectrum using  ISO 15390, DLR version or  ISO 15390 models. This features is not available for forecast simulations.



The result page contains the figure of modulated spectrum and and correspondent tabulated data.
Text file and numpy/python archive are also available for Download.


Advanced Controls:

For expert users it is available the possiblity to modify some relevant HelMod parameters.

Available parameters may change for different HelMod version. For latest default parameters please refer to Current and History of default parameters page.

HelMod provide optimized LIS developed with GALPROP and presented on international journals, Expert users may load their own develped LIS. HelMod accept the following formats:

  • GALPROP fits file (*.gz extension). The fits must contain at least the computed LIS for the Galactic Cosmic Rays particle species to be modulated. The Module evaluate the LIS for modulation as the sum of modulated primary spectrum with  secondaries and modulated isotopes.
  • plaintext file. User can provide a txt file for LIS with the follow characteristics:
    • The file should have a mime type 'text/plain' (Checkout this list for allowed extensions).
    • The file must contains two columns only: one for kinetic energy per nucleon [GeV], the second for the LIS flux [ (m\(^2\) s sr GeV)\(^{-1}\)].
    • The file can contains comments. Line starting with '#' character will be ignored.


It should be remarked that data generated by using the Calculator may be used by HelMod developers for statistical purpose.