**1. NAME AND TITLE**

TNG1: A Multistep Statistical Model Based on the Hauser-Feshbach Theory For The Evaluation Of Neutron Data.

**2. CONTRIBUTORS**

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

**3. CODING LANGUAGE AND COMPUTER**

Fortran 77; VAX 6000.

**4. NATURE OF PROBLEM SOLVED**

The TNG1 code is a multistep statistical model based on the Hauser-Feshbach theory including width-fluctuation corrections and pre-compound effects. Statistical model calculations are frequently performed for medium and heavy nuclei.

**5. METHOD OF SOLUTION**

The Hauser-Feshback part of the TNG1 code is multi-step, but angular distribution can be calculated only for the binary step. The pre-compound portion is single step, in this case angular distribution is calculated on the basis of partial wave interference (partial relaxation of the random phase approximation in the H-F formalism). Quantities calculated include: elastic, total, inelastic, (n,g), (n,n'), (n,p), (n,a), (n,f), (n,2n), (n,np), (n,na), (n,nf),..., (n,4n),......, secondary particle and gamma ray production spectra, angular distributions of the first outgoing particles, and the production cross sections of isomeric states.

**6. RESTRICTIONS OR LIMITATIONS**

(n,gx) has not been included. Dimensions of the transmission coefficients are such that cross sections can be calculated up to 40 MeV for Ca-40 and 20 MeV for Pu-242. The maximum number of discrete levels is 40, the number of continuum bins is limited to 40 for each residual nuclide, and the number of outgoing particles is limited to 3.

**7. TYPICAL RUNNING TIME**

On an the VAX 6000, sample problem 1 took about 2 minutes of CPU time (wall clock time).

**8. COMPUTER HARDWARE REQUIREMENTS**

TNG1 runs on the VAX family of computers.

**9. COMPUTER SOFTWARE REQUIREMENTS**

A Fortran 77 compiler is required. The code was compiled with VAX/Fortran on the VAX 6000 under the VAX/VMS operating system.

**10. REFERENCES**

K. Shibata and C. Y. Fu, *Recent Improvements of the TNG Statistical Model Code*, ORNL/TM-10093, Oak Ridge National Laboratory, Oak Ridge, Tennessee, August 1986.

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced documents and one DS/DD 5.25-inch diskette (360 K) which contains the source code and sample problem input and output.

**12. DATE OF ABSTRACT**

January 1991.

**KEYWORDS: ** EXPERIMENTAL DATA ANALYSIS; NEUTRON; NUCLEAR
MODELS