Welcome to the home of the MCNPX code!
MCNPX is a general-purpose Monte Carlo radiation transport code for modeling
the interaction of radiation with everything. MCNPX stands for Monte Carlo
N-Particle eXtended. It extends the capabilities of MCNP4C3 to nearly all
particles, nearly all energies, and to nearly all applications without
an additional computational time penalty. MCNPX
is fully three-dimensional and time dependent. It utilizes the latest nuclear
cross section libraries and uses physics models for particle types and energies
where tabular data are not available. Applications range from outer space
(the discovery of water on Mars) to deep underground (where radiation is used
to search for oil.) MCNPX is used for nuclear medicine, nuclear safeguards,
accelerator applications, nuclear criticality, and much more.
MCNPX is written in Fortran 90, runs on PC Windows, Linux, and unix platforms,
and is fully parallel (PVM and MPI). As a superset of MCNP4C3, MCNPX does everything
MCNP4C3 does and much more: see the 1-page MCNPX Features Summary:
Features.pdf,
Features.doc.
MCNPX Beta Release
MCNPX (source code, executables, data) is available from this WWW site to
"beta testers" who have access to intermediate code versions. Beta versions of
MCNPX are available from "The Code" tab on the left. Beta Testers are sponsors,
collaborators, and those who take MCNPX workshops (see "Classes tab on right.) For further
information on the Beta Test program, contact
mcnpx@lanl.gov.
The latest beta test version is MCNPX 26F (March 24, 2008).
The principal new capabilities added since the latest RSICC release
(MCNPX 2.5.0, April 2005) are:
- Inline continuous-energy burnup / depletion (BURN card); *
- Heavy ion transport - MCNPX now transports 2000+ particles; *
- Delayed gamma emission;*
- LAQGSM physics package;*
- CEM03 physics package replacing CEM2K;
- Spherical mesh weight windows;
- Energy-time weight windows;
- File names longer than 8 characters;
- Muon capture interaction physics;
- Spherical mesh tally plots;
- Vacation Matrix criticality source convergence acceleration;
- Charged ions from neutron capture in table range;
- Ability to terminate calculations based upon tally precision (STOP card);
- Total nu now default for neutron fission;
- Numerous additional enhancements and corrections. *
* = new or significantly enhanced capabilities in MCNPX26F
added since MCNPX26E (November 17, 2007).
These new MCNPX 26F features are described in: "MCNPX V26F Extensions"
LA-UR-08-1808.pdf, LA-UR-08-1808.doc (March 24, 2008) (73 pages).
MCNPX RSICC International Release
MCNPX is available (source code, executables, data) to nearly everyone (subject to export
controls on sensitive countries) from the Radiation Safety Information
Computational Center (RSICC)
in Oak Ridge, TN. MCNPX is packaged with MCNP5 and
the nuclear data common to both codes. Be sure to specify that you want the whole package,
MCNPX, MCNP5, and data.
The last RSICC release is version of MCNPX 2.5.0 (April 2005).
The principal new capabilities added since MCNP4C3 (2000) and MCNPX 2.3.0 are:
- Mesh tallies generated and plotted within MCNPX and superimposed over
geometry plots
MeshTal.pdf,
MeshTal.doc;
- Pulse-height tallies with variance reduction
PHT_VRT.pdf,
PHT_VRT.doc;
- Radiography tallies and 2D contour plots
Contour.pdf,
Contour.doc;
- MPI and PVM multiprocessing. Criticality calculations 100 x faster
MPI-Crit.pdf,
MPI-Crit.doc.
- Geometry plots have 64-colors, can shade by different cell quantities, and can
label i,j,k indices
ijk.pdf,
ijk.doc.
- The ability to use physics models when cross section tables are missing
(see a BGO example: BGO.pdf,
BGO.doc);
- Physics models include Bertini, Dresner, ISABEL, CEM03, and INCL4/ABLA
Models.pdf,
Models.doc).
- Photonuclear and proton plots
PN.pdf,
PN.doc;
- Light-ion recoil
LIR.pdf,
LIR.doc;
- 3-He coincidence tallies;
- Default dose functions;
- Positron sources;
- Spontaneous fission sources;
- Fission multiplicity;
- Coincidence capture tallies;
- Anticoincidence pulse-height tallies;
Many of these features are described in more detail in an 80-page document,
"MCNPX Extensions, Version 2.5.0"
LA-UR-05-2675.pdf (.6 MB),
LA-UR-05-2675.doc (1.0 MB).
Downlolading Caution
Cash Awards
We are so confident in the quality of MCNPX that we pay cash awards to the first person identifying any bug or error in the code. See the list of cash awards (4 pages):
Cash.pdf,
Cash.doc.
Considering all the new MCNPX capabilities relatively few bugs have been identified. It is far easier to find an error in the predecessor codes to MCNPX than in the new capabilities added.
Last modified: March 24, 2008
To report errors on the web page, or make other comments, contact
Gregg W. McKinney / 505-665-8367