NEA-1775 ZZ-CLES.

1. NAME OR DESIGNATION OF PROGRAM:  ZZ-CLES.

3. DESCRIPTION OF PROGRAM OR FUNCTION

It consists of 36 sets of 140-group-constants (energy-averaged cross sections) for seven different moderator materials in liquid and solid phases at given temperatures:
- Liquid He-4 at 0.1, 0.3, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5 K,
- Liquid ortho-, para- and normal- molecular hydrogen at 14.0, 20.4 K,
- Liquid ortho-, para- and normal- molecular deuterium at 18.7, 23.6 K,
- Solid methane at 20.4, 50.0, 90.7 K,
- Liquid methane at 90.7, 111.7 K,
- Liquid light water at 278, 300, 325, 350 K,
- Liquid heavy water at 278, 300, 325, 350 K.
All the sets are generated in the following form/1/:
- Neutron energy range between 0.1 micro-Ev and 10 MeV,
- Total of 140 energy groups at equal logarithmic energy intervals(i.e. 10 groups per energy decade),
- Expansion of the angular distribution of scattered neutrons in Legendre polynomials up to order 3,
- Weighting energy spectrum by a combination of Maxwellian, 1/E and fission spectra for neutron energy E,
- Microscopic cross sections (b/molecule) in terms of text format(2 MB/set) and ANISN-type cross section table (length IHM=282, position IHT=3, groups IGM=140) though not multiplied by the Legendre factor (2*l+1).

4. METHODS

The high-energy part for E>=1 eV(energy group g<70) and the low-energy part for E<=10 eV(g>= 60) are made up separately and then combined into one set. The overlapping energy region between 1 and 10 eV is prepared to make a gradual transition between the two parts. The high-energy part is produced using the Japanese evaluated nuclear data library JENDL-3.3/2/ and the nuclear data processing program NJOY/3/. The low-energy part is created by use of double-differential scattering cross section models developed theoretically for liquid and solid moderator materials. Low-energy neutron scattering by molecular dynamics inherent to each material is fully taken into account and the calculated cross-section results are compared with many experimental measurements, both double-differential and total, at liquid and solid temperatures. Slowing-down and thermalization properties are also examined with neutron energy spectra calculated numerically for moderator models.
All the results are reported in research papers on scientific journals, which are given for each material by paper(s) on cross section model and spectral analysis: liquid He-4/4/5/, liquid molecular H/6/7/, liquid molecular D/8/9/, solid methane/10/11/, liquid methane/10/11/, liquid light water/12/13/, and liquid heavy water/14/13/. Numerical methods for calculation of low-energy neutron scattering cross sections are described in detail and illustrated with physical cross section models/1/.

8. RELATED OR AUXILIARY PROGRAMS

A Fortran program, CLES.trans.for, is available to produce cross section tables for specific neutron transport calculations, both deterministic and Monte Carlo. The major recipes are as follows:
- Listing the total cross sections of scattering and absorption, the group-to-group transfer cross sections, and the upper- and lower-energy boundaries for all groups,
- Multiplying microscopic scattering cross sections (b/molecule) by the factor (2*l+1) to construct an ANISN-type cross section table,
- Calculating macroscopic scattering cross sections (1/cm) by the input value for number density N (molecules/cm**3): although an equilibrium or theoretical value of N for each material at given temperature is preset, it may be necessary to give any other values in practical cases such as boiling liquid and non-crystalline solid/7,11/,
- Varying the magnitudes of absorption cross section sigma_a(b/molecule) according to the expression p*sigma_a=+ q(v_th/v) with two arbitrary constants p (as a factor) and q (b/molecule) for neutron speeds v at E and v_th at E = 25 meV/13/,
- Merging two group-constant sets in a new one for mixed materials such as, for instance, liquid normal molecular hydrogen with a para:ortho ratio of 1:3/7/, liquid normal molecular D with a para:ortho ratio of 1:2/9/ and liquid heavy water contaminated with liquid light water/13/.

10. REFERENCES

/1/N.Morishima:
Numerical Methods for Calculation of Low-Energy Neutron Scattering Cross Sections
J. Neutron Res. 13(2005) 225-240.
/2/K.Shibata et al.:
Japanese Evaluated Nuclear Data Library Version 3 Revision-3: JENDL-3.3
J. Nucl. Sci. Technol. 39(2002) 1125-1136.
/3/R.E.MacFarlane, D.W.Muir:
The NJOY Nuclear Data Processing System, Version 91
LA-12740-M, Los Alamos National Laboratory, October 1994.
/4/N.Morishima, Y.Abe:
Evaluation of Cold-Neutron Scattering Cross Sections for Liquid He-4 at Temperatures between 1 and 4.2 K
Nucl. Instr. And Method-A, 397(1997) 354-364;
- Y.Abe, N.Morishima:
Ultracold and Cold Neutron Cross Sections of Liquid 4He at Low Temperatures down to 0.1 K
Nucl. Instr. And Method-A, 459(2001) 256-264;
- N.Morishima, M.Sakakibara:
Ultracold Neutron Production by the Phonon Excitation in Superfluid 4He at Temperatures below 1 K
J. of Neutron Res. 8(2000) 233-243.
/5/Y.Abe, N.Morishima:
Neutronic Study of UCN Production and Storage in a Liquid He-4 Source
Nucl. Instr. And Method-A, 481(2002) 414-421.
/6/N.Morishima, D.Mizobuchi:
Cross Section Models for Cold Neutron Scattering from Liquid H2 and D2
Nucl. Instr. And Method-A, 350(1994) 275-285;
- N.Morishima, A.Nishimura:
On the Yield of Cold and Ultracold Neutrons for Liquid H2 at Low Temperatures near the Melting Point
Nucl. Instr. And Method-A, 426(1999) 638-641.
/7/N.Morishima, Y.Matsuo:
Cold Neutron Production in Liquid para- and normal-H2 Moderators
Nucl. Instr. And Method-A, 490(2002) 308-315.
/8/N.Morishima:
Cold and Thermal Neutron Scattering Cross Sections of Liquid H2 and D2 at Temperatures between Melting and Boiling Points
Ann. Nucl. Energy, 27(2000) 505-516;
- N.Morishima, Y.Nishikawa:
Cold and Thermal Neutron Scattering Cross Sections of Liquid H2 and D2. II: Improvement on Coherent Scattering
Ann. Nucl. Energy, 31(2004) 737-745.
/9/Y.Matsuo, N.Morishima, Y.Nagaya:
Neutronic Study of Spherical Cold Neutron Sources composed of Liquid H2 and D2
Nucl. Instr. And Method-A, 496(2003) 446-451.
/10/N.Morishima, Y.Sakurai:
Cross-Section Model for Cold Neutron Scattering in Solid and Liquid CH4
Nucl. Instr. And Method-A, 490(2002) 527-537.
/11/N.Morishima, T.Mitsuyasu:
Cold Neutron Production in Solid and Liquid CH4 Moderators
Nucl. Instr. And Method-A, 517(2004) 295-300;
- T.Mitsuyasu, N.Morishima, Y.Nagaya:
Cold Neutron Production in Solid and Liquid CH4 Moderators II: on the Reentrant-Hole Configuration
Nucl. Instr. And Method-A, 537(2005) 610-613 (2005).
/12/Y.Edura, N.Morishima:
Cold and Thermal Neutron Scattering in Liquid Water: Cross-Section Model and Dynamics of Water Molecules
Nucl. Instr. And Method-A, 534(2004) 531-543.
/13/Y.Edura, N.Morishima:
Generation of Neutron Multigroup Constants in the Energy Range 0.1 micro-eV-10 MeV for Light and Heavy Water at Four Different Temperatures,
Nucl. Instr. And Method-A, 560(2006) 485-493.
/14/Y.Edura, N.Morishima:
Cold and Thermal Neutron Scattering in Liquid Water-II: Scattering Laws and Group Constants for H2O and D2O
Nucl. Instr. And Method-A, 545(2005) 309-318.

- N. Morishima:
CLES: Cross Section Library of Moderator Materials for Low-Energy Neutron
Sources (November 2006)
- Yutaka Abe and Nobuhiro Morishima:
Neutron Multigroup Constant Sets of Moderator Materials for Design of
Low-Energy Neutron Sources, published in Proceedings of the 2006 Symposium on
Nuclear Data January 25-26, 2007, RICOTTI, Tokai, Japan (JAEA-Conf 2008-006,
September 2008)

15. NAME AND ESTABLISHMENT OF AUTHORS

N. Morishima
Department of Nuclear Engineering, Kyoto University,
Yoshida, Sakyo-ku, Kyoto 606-8501, Japan

INFO.FIL                     Information file
howtouse.txt                 User instructions
ZZ-CLES.Abstract.pdf         Abstract
CLES.description.pdf         Data library report
CLES.energy.boundaries.txt   Energy boundaries
CLES.process.for             Fortran source
AN140.LCH4.111.7K.txt        Data library
AN140.LCH4.90.7K.txt         Data library
AN140.LD2.normal.18.7K.txt   Data library
AN140.LD2.normal.23.6K.txt   Data library
AN140.LD2.ortho.18.7K.txt    Data library
AN140.LD2.ortho.23.6K.txt    Data library
AN140.LD2.para.18.7K.txt     Data library
AN140.LD2.para.23.6K.txt     Data library
AN140.LD2O.278K.txt          Data library
AN140.LD2O.300K.txt          Data library
AN140.LD2O.325K.txt          Data library
AN140.LD2O.350K.txt          Data library
AN140.LH2.normal.14K.txt     Data library
AN140.LH2.normal.20.4K.txt   Data library
AN140.LH2.ortho.14K.txt      Data library
AN140.LH2.ortho.20.4K.txt    Data library
AN140.LH2.para.14K.txt       Data library
AN140.LH2.para.20.4K.txt     Data library
AN140.LH2O.278K.txt          Data library
AN140.LH2O.300K.txt          Data library
AN140.LH2O.325K.txt          Data library
AN140.LH2O.350K.txt          Data library
AN140.LHE4.0.1K.txt          Data library
AN140.LHE4.0.3K.txt          Data library
AN140.LHE4.0.5K.txt          Data library
AN140.LHE4.0.6K.txt          Data library
AN140.LHE4.0.7K.txt          Data library
AN140.LHE4.0.8K.txt          Data library
AN140.LHE4.0.9K.txt          Data library
AN140.LHE4.1.0K.txt          Data library
AN140.LHE4.1.5K.txt          Data library
AN140.LHE4.2.0K.txt          Data library
AN140.LHE4.2.5K.txt          Data library
AN140.SCH4.20.4K.txt         Data library
AN140.SCH4.50K.txt           Data library
AN140.SCH4.90.7K.txt         Data library