1. **NAME AND TITLE**

CASTHY: Statistical Model Calculation for Neutron Cross Sections and Capture Gamma-Ray Spectra.

2. **CONTRIBUTOR**

Japan Atomic Energy Research Institute, Tokai-mura, Japan.

3. **CODING LANGUAGE AND COMPUTER/OPERATING SYSTEM**

Fortran 77, FACOM computers and IBM RISC 6000.

4. **NATURE OF PROBLEM SOLVED**

This code has been utilized as a tool for nuclear data evaluations. It is used to
calculate neutron cross sections of total, shape elastic scattering and compound nucleus
formation with the optical model, and compound elastic scattering, inelastic scattering and
capture cross sections by the statistical model applying Hauser-Feshbach and/or Moldauer
formula. The other cross sections such as the *(n,2n), (n,p), (n,f)* reactions are treated as
cross sections of competing processes, and their sum is given through input data. This
code calculates also capture gamma-ray spectra. Branching ratio for primary transition
can be treated in a particular way, if necessary.

5. **METHOD OF SOLUTION**

The total transmission coefficient is modified so that the total reaction cross section obtained by using the optical model may be conserved. The transmission coefficients for neutrons and gamma-rays are rewritten by considering an effect of (n,gamma-n') process.

6. **RESTRICTIONS OR LIMITATIONS**

For the normalization of cross section, the normalization energy point should be included in the incident energy points of input data. Some other limitations exist depending on options.

7. **TYPICAL RUNNING TIME**

On an IBM RISC system 550, sample problems 1, 2, and 3 took 14.6, 15.8 and 86.9 seconds respectively.

8. **COMPUTER HARDWARE REQUIREMENTS**

The code was developed on the FACOM computers and tested on the IBM RISC 6000.

9. **COMPUTER SOFTWARE REQUIREMENTS**

The code was written in Fortran 77 and tested using the xlf Fortran compiler under the AIX 3.1 operating system on the IBM RISC 6000.

10. **REFERENCE**

S. Igarasi and T. Fukahori, "Program CASTHY - Statistical Model Calculation for Neutron Cross Sections and Gamma Ray Spectrum," JAERI-1321 (March 1991).

11. **CONTENTS OF CODE PACKAGE**

Included are the referenced document and one DS/HD (1.2MB) 5.25-in. diskette which includes the source files, sample input and output.

12. **DATE OF ABSTRACT**

September 1992.

**KEYWORDS: ** GAMMA-RAY SPECTRUM ANALYSIS; NEUTRON; NUCLEAR
MODELS; PARAMETRIC MODELS