Welcome to OLTARIS,
Tool for the
OLTARIS is an integrated tool set utilizing HZETRN (High Charge and Energy Transport).
These tools are intended to help scientists and engineers study the effects of space
radiation on shielding materials, electronics, and biological systems.
Mars surface environments (SPE and GCR) have been added. The Mars environments can only be
used with vehicle thickness distributions and are always executed using ray-by-ray
transport. A surface-local-vertical vector needs to be defined to indicate which
hemisphere is up and exposed to the atmosphere. The opposite hemisphere
is assumed to be regolith. A Field-of-View (FOV) response has also been added for
Mars surface projects to aid in comparisons to particle telescope-type instruments.
Generalized spheres can now be created and used for project geometries. These spheres are
defined similarly to slabs and can contain any number of layers and materials.
These jobs are run using forward-only transport and
effective dose calculations use an orientation-averaged or spinning astronaut
The Badhwar-O'Neill 2010 GCR model has been added and is now the default. The
2004 model is also still available.
Lunar albedo netrons have been added to the Lunar surface environments for both
interpolation-based and ray-by-ray based jobs.
Vehicle analysis may now be performed using a ray-by-ray transport approach.
This methodology allows thickness distributions with as many as 100 user-defined
materials and layers in any order. An improved transport model with
forward/backward neutrons is also included in the analysis. In contrast to
traditional interpolation-based methods, the RBR approach allows for a more
complex vehicle description and provides a more accurate vehicle analysis capability.
Users may upload a trajectory and have analysis performed at every point along the
trajectory. This type of analysis allows exposure levels to be calculated as a
function of time providing a more detailed trajectory analysis for a given vehicle.
There are no charges associated with the use of OLTARIS, but users
must register and get approval from the site administrators
before accessing the site contents. New users should click
the Register button above and complete the
Sign-up Form for OLTARIS page. After registration is complete,
one of the site administrators will activate your account when approved,
and confirmation will be sent to the supplied email address.
Existing users can login using their given username and password.
Click the Forgot my password link and your password will be sent to
the email address you supplied when the account was created.
OLTARIS requires a browser (Internet Explorer
and Mozilla Firefox have been tested) with
This site is intended for knowledgeable users of this class of tools.
Once inside the site, a users guide can be found under the
This is an evolving tool set; new capabilities can and will be added.
Please contact the site administrator
with comments and suggestions.
User Selected Environment(s)
- Free Space Galactic Cosmic Ray (GCR)
- Select historical solar minimum or maximum and input duration
- Input start and end dates
- Input solar modulation parameter
- Free Space Solar Particle Event (SPE)
- Select historical spectra
- Input parameters for a specific fitting function
- Earth Orbit
- Circular orbit by start/end data, altitude, inclination
- Upload user-defined trajectory
- Lunar surface with neutron albedo
- Mars surface with atmosphere and neutron albedo
- Europa Mission Design Environments
User Defined Geometry
- Upload thickness distribution(s)
- Interpolation-based analysis limited to three user-defined materials/layers
- Ray-by-ray analysis is currently limited to 100 user-defined materials/layers
Slabs can be defined with any number of materials/layers in any order
Spheres can be defined with any number of materials/layers in any order
User Defined Materials
Materials can be defined by:
Elemental Mass Percentage
Molecular Mass Percentage
User Selected Response Function(s)
Differential Flux / Fluence
Dose in tissue or silicon
Dose Equivalent (ICRP60)
Whole-Body Effective Dose Equivalent CAM, CAF, MAX, and FAX
TLD-100 (Thermo-Luminescent Dosimeter)
TEPC (Tissue Equivalent Proportional Counter)
LET (Linear Energy Transfer) in tissue or silicon
The OLTARIS development team is always in
the process of making improvements and additions to the site.
If you encounter an issue you feel is a bug in the product, please let us know about it.
You can use the links which are posted at the top of each page or those here:
Report a Bug /
Send a Comment
for reporting bugs and submitting comments.
The OLTARIS development team appreciates your feedback!
Here is a list of known issues:
If different units are selected for electron transport results (Europa environments) in multiple tabs
in one browser, the plots and downloads will be in the units that were selected last. If you stay in
the same units for all tabs, everything will be correct.
Help documents and user guides may not be up to date. If it doesn't agree with what's on the page,
it probably just needs to be updated. Please let us know.