RSICC DATA LIBRARY DLC-220

1. NAME AND TITLE OF DATA LIBRARY

HILO2K: Coupled 83 Neutron, 22 Photon Group Cross Sections for Neutron Energies Up to 2 GeV.

2. NAME AND TITLE OF DATA RETRIEVAL PROGRAMS

LCAT: Converts ANISN card-image data to binary format and other functions.

PRTXS: Print selected cross sections from binary files.

3. CONTRIBUTOR

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

4. HISTORICAL BACKGROUND AND INFORMATION

HILO2k is a new high-energy neutron and photon transport cross-section library containing neutron cross sections to 2 GeV and photon cross sections to 20 MeV and is intended for use in multidimensional deterministic transport codes. It represents the culmination of work directed at updating and extending the DLC-119/HILO86 transport cross-section library developed at Oak Ridge National Laboratory (ORNL) in the mid 1980's.

5. APPLICATION OF THE DATA

HILO2k was developed as part of the neutronics R&D effort associated with the design of the Spallation Neutron Source (SNS) currently under construction at ORNL and can be used for other accelerator driven applications. HILO2k multigroup cross sections are in the form needed for the CCC-650/DOORS3.2a (ANISN, DORT and TORT) discrete ordinates codes. In addition to transport cross sections, the new HILO library contains flux-to-dose conversion factors and kermas (nuclear heating response functions) for all energies for all 32 nuclides. It also contains dpa and H-1 and He gas production response functions covering selected energy ranges for some of the nuclides comprising structural materials.

6. SOURCE AND SCOPE OF DATA

The new library contains transport cross sections for 32 nuclides commonly found in the target, reflector, and shielding materials used at spallation neutron source facilities. The high-energy portion (E>20 MeV) of HILO2k is based on neutron elastic and nonelastic interaction and production data generated using the stochastic nuclear collision models in MCNPX Version 2.1.5 (RSICC package C00705MNYCP01). The low-energy portion was derived from ENDF or LENDL data for all nuclides except Hg. The high-energy neutron interaction and production cross sections were also normalized to the nonelastic cross sections for those nuclides treated in the recently evaluated Los Alamos National Laboratory (LANL) 150-MeV library. Dose equivalent obtained from discrete ordinates transport calculations employing HILO2k agreed within approximately a factor of two with that obtained using MCNPX after transport through more than 4000 g/cm2 of typical high-energy shielding materials. Data are provided for: H-1, H-2, He, Be, B-10, B-11, C, N, O, Na, Mg, Al, Si, S, K, Ca, Cr, Mn, Fe, Ni, Cu, Zr, Nb, Cd, Ba, Gd, Ta, W, Hg, Pb, U-235, U-238.

Two versions of the new HILO library are distributed. In the standard version, all high energy particle interaction and production data was taken into account to obtain the group total cross section (interaction cross section) and the group-to-group Legendre scattering coefficients (scattering cross sections). In the modified version, neutrons that exited collisions almost straight ahead with more than 95% of the incident neutron energy were treated as uncollided neutrons. Both libraries contain 105 total energy groups (42 high-energy neutron, 41 low-energy neutron, and 22 photon groups). The modified version of the new HILO library contains P₉ Legendre expansions for the scattering cross sections whereas the standard version contains P₁₀ expansions

7. DISCUSSION OF THE DATA RETRIEVAL PROGRAM

LCAT (Library Conversion, And Truncation code) was written to convert the FIDO free-form ASCII libraries to binary ANISN libraries and may also be used to create smaller truncated versions of both libraries. PRTXS reads the binary file and creates a file that can be printed or viewed with an editor. The codes were developed using the XLF compiler on IBM RS/6000 under AIX and have been run on personal computers under RedHat Linux using g77 0.5.26. LCAT and PRTXS run interactively and query the user for filenames and options.

8. DATA FORMAT AND COMPUTER

ASCII card images; Many computers (D00220/MNYCP/00).

9. TYPICAL RUNNING TIME

LCAT converts ANISN formatted data from card image to binary within a few seconds.

10. REFERENCES

a. Documentation available with library:

R. A. Lillie and F. X. Gallmeier, "HILO2k: A New HILO Library to 2 GeV," Informal paper (September 2003).

b. Other useful documentation:

R. A. Lillie and F. X. Gallmeier, "HILO Transport Cross-Section Library Extension," Proc.33rd Int.Top. Meet.Nucl. Applicat. of Accel.Tech., Long Beach, CA (1999).

R. A. Lillie and F. X. Gallmeier, "HILO2k: A Coupled Neutron-Photon Transport Cross-Section Library for Neutron Energies up to 2000 MeV," Proc. 4th Int. Top. Meet. Nucl. Applicat. of Accel. Tech., Washington, DC (2000).

R. A. Lillie, F. X. Gallmeier, and J. O. Johnson, "HILO2k: Transport Cross Sections for Neutron Energies to 2 GeV," Proc. of the 2001 Amer. Nucl. Soc. Rad. Prot. & Shld. Div. Top. Meet., Santa Fe, NM (2001).

R. G. Alsmiller, Jr., J. M. Barnes, and J. D. Drischler, "Neutron Photon Multigroup Cross Sections for Neutron Energies Less Than or Equal to 400 MeV (Revision 1)," ORNL/TM-9801 (February 1986).

11. CONTENTS OF LIBRARY

The package is distributed in a compressed Unix tar file on a CD. Included are the referenced document in (10a), Fortran programs, and cross sections in ASCII card images.

12. DATE OF ABSTRACT

March 2004.

KEYWORDS: ANISN FORMAT; COUPLED NEUTRON-GAMMA-RAY CROSS SECTIONS; INTRANUCLEAR CASCADE; MULTIGROUP CROSS SECTIONS; NEUTRON CROSS SECTIONS