Home Academic Reports Classes FAQ Forum Getting The Code Manual Reference Collection User Symposia Contact the MCNP Team

User Manual

MCNP6.3 Theory & User Manual

Until the MCNP6.3 release is completed and the total software product (code + documentation) is available to users, the theory & user manual that corresponds to that release is available here as both a preview of new capabilities and as a reference for features that overlap with MCNP6.2.

J. A. Kulesza, T. R. Adams, J. C. Armstrong, S. R. Bolding, F. B. Brown, J. S. Bull, T. P. Burke, A. R. Clark, R. A. Forster III, J. F. Giron, A. S. Grieve, C. J. Josey, R. L. Martz, G. W. McKinney, E. J. Pearson, M. E. Rising, C. J. Solomon Jr., S. Swaminarayan, T. J. Trahan, S. C. Wilson, and A. J. Zukaitis. MCNP® Code Version 6.3.0 Theory & User Manual. Los Alamos National Laboratory Tech. Rep. LA-UR-22-30006, Rev. 1. Los Alamos, NM, USA. September 2022.
 PDF

Current User Manual

MCNP6.2 User Manual & Release Notes

Previous Manuals

Note that effective November 26, 2001, the Office of Export Control Policy and Cooperation has required that the MCNP User Manual be removed from all publicly-accessible websites. Further review may allow us to repost the manual someday.

Code Version 6.1.1beta

MCNP6 Users Manual - Code Version 6.1.1beta, LA-CP-14-00745 (June 2014).
The manual is provided in the MCNP6 release package available from RSICC, and is NOT accessible from this webpage or the MCNP Reference Collection.

Code Version 6.1

MCNP6 Users Manual - Code Version 6.1, LA-CP-13-00634 (May 2013).
The manual is provided in the MCNP6 release package available from RSICC, and is NOT accessible from this webpage or the MCNP Reference Collection.

Code Version 5

The manual was corrected and updated (as of Nov. 2005) to include the new features found in MCNP Version 5 (MCNP5)-RSICC_1.40. The manual was also split into 3 volumes:

  • Volume I: MCNP Overview and Theory Chapters 1, 2 and Appendices G, H (LA-UR-03-1987)
    This volume provides an overview of the capabilities of MCNP5 and a detailed discussion of the theoretical basis for the code. The first chapter provides introductory information about MCNP5. The second chapter describes the mathematics, data, physics, and Monte Carlo simulation techniques which form the basis for MCNP5. This discussion is not meant to be exhaustive - details of some techniques and of the Monte Carlo method itself are covered by references to the literature.
  • Volume II: MCNP User's Guide Chapters 1, 3, 4, 5 and Appendices A, B, I, J, K (LA-CP-03-0245)
    This volume provides detailed specifications for MCNP5 input and options, numerous example problems, and a discussion of the output generated by MCNP5. The first chapter is a primer on basic MCNP5 use. The third chapter shows the user how to prepare input for the code. The fourth chapter contains several examples, and the fifth chapter explains the output. The appendices provide information on the available data libraries for MCNP, the format for several input/output files, and plotting the geometry, tallies, and cross-sections. The manual is provided in the MCNP6 release package available from RSICC, and is NOT accessible from this webpage or the MCNP Reference Collection.
  • Volume III: MCNP Developer's Guide Appendices C, D, E, F (LA-CP-03-0284) This volume provides details on how to install MCNP on various computer systems, how to modify the code, the meaning of some of the code variables, and data layouts for certain arrays. The manual is provided in the MCNP6 release package available from RSICC, and is NOT accessible from this webpage or the MCNP Reference Collection.

Older Versions

J. F. Briesmeister (Ed.), et. al. MCNPTM—A General Monte Carlo N-Particle Transport Code. Los Alamos National Laboratory Tech. Rep. LA-13709-M. Los Alamos, NM, USA. December 2000. Code Version 4C, also Univ. of California Tech. Report UC-700.
 PDF

J. F. Briesmeister, T. E. Booth, D. G. Collins, J. J. Devaney, G. P. Estes, H. M. Fisher, R. A. Forster, T. N. K. Godfrey, J. S. Hendricks, H. G. Hughes, R. C. Little, R. E. Prael, R. G. Schrandt, R. E. Seamon, E. C. Snow, W. L. Thompson, W. T. Urban, J. T. West. MCNP—A General Monte Carlo Code for Neutron and Photon Transport. Los Alamos National Laboratory Tech. Rep. LA-7396-M, Rev. 2. Los Alamos, NM, USA. September 1986. Code Version 3A, also Univ. of California Tech. Report UC-32.
 PDF

LASL Group TD-6. MCNP—A General Monte Carlo Code for Neutron and Photon Transport. Los Alamos National Laboratory Tech. Rep. LA-7396-M, Rev. 1. Los Alamos, NM, USA. November 1979. Code Version 2.
 PDF

LASL Group TD-6. MCNP—A General Monte Carlo Code for Neutron and Photon Transport. Los Alamos National Laboratory Tech. Rep. LA-7396-M. Los Alamos, NM, USA. July 1978. Code Version 1.
 PDF