Cosmic ray intensities and radiation protection quantities in the atmosphere


cosmic rays in earth's atmosphere

Our atmosphere protects us from a hostile space radiation environment comprised of high energy particles of solar and intergalactic origin

  • solar radiation is significant during unpredictable and short lived solar flares and coronal mass ejections (CMEs).
  • galactic cosmic radiation (GCR) is omnipresent. The GCR intensity varies with latitude, longitude, and time of year due to effects of solar activity on the interplanetary magnetic field.

Space radiation collides with the nuclei of gases in the atmosphere, leading to a cascade of nuclear and electromagnetic reactions. The result is a complex shower of high energy radiation, the intensity and composition of which varies spatially and temporally.

predictive modelling of aviation radiation

Excessive exposure to radiation can damage DNA and lead to long-term health effects such as an increased risk of cancer.

Radiation levels at altitudes used by commercial aircraft are greater than at sea level due to cosmic rays. Aircrew are classified as radiation workers in some countries; however, planning to limit their exposure, and monitoring, is generally lacking.

Both real-time measurements and predictive modelling of radiation in the atmosphere are important to mitigate the radiation risk to assets and crew.

Amentum Aerospace has developed a RESTful API based on the PARMA and CARI-7 parameterised models of GCR induced radiation in the atmosphere. The API provides radiation doses and other quantities on a particular date, latitude, longitude, and altitude.


dose calculation

Understanding the effective dose to aircrew is important to ensuring their exposure does not exceed safe limits.

The example to the right shows the API called from Python code (see the validation section for more examples like this). Click the Play icon to run the code. The API returns the value and units of the dose rate in JSON format for the PARMA and CARI-7 endpoints.


The API documentation is available here for the PARMA model and here for the CARI-7 model.

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differential intensity spectra

The radiation environment is often characterised by measuring the spectrum of energies of different particle types. Predictive models must be able to accurately reproduce these experimental measurements. The information is also important for atmospheric research.

The example to the right shows the API called using the CURL command line program. The API returns the energy differential intensity spectrum in JSON format as two arrays. The first array is the energy (in MeV); the second is the corresponding intensity (in /cm2/sr/MeV/s).