1. NAME AND TITLE

TRAX: A Program For Optics of Curved Crystal Neutron Spectrometers.

2. CONTRIBUTOR

Institute for Nuclear Power Reactors, Pitesti, Romania, through the NEA Data Bank, Gif-sur-Yvette Cedex, France.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; CDC Cyber.

4. NATURE OF PROBLEM SOLVED

TRAX computes the resolution matrix and characteristic line widths and intensities for three-axis slow-neutron spectrometers with flat or curved, mosaic or perfect crystals, with or without Soller collimators or limiting diaphragms.

5. METHOD OF SOLUTION

The matrix computational technique is used. A library of data on crystal monochromators is built into the program. The analytical optimization is computed through formulae valid for perfect curved thin crystals. The numerical optimization is performed by searching iteratively for the minimum of an optimization parameter with the aid of numerical subroutines.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

On the CDC Cyber 170, the CPU time is less than 1 second per case. For numerical optimization, the run time increases rapidly with the number of variables. For 3 variables, it is less than 1 minute; for 6 variables, it is less than 6 minutes.

The test case in the package has been run at NEA-DB on a CDC Cyber 830 in 1.4 seconds of CPU time.

8. COMPUTER HARDWARE REQUIREMENTS

The code runs on the CDC Cyber computers, model 170 and 830.

9. COMPUTER SOFTWARE REQUIREMENTS

The code was written in Fortran IV and runs on the Cyber computers under the NOS operating system. The IMSL library of mathematical subroutines is required.

10. REFERENCE

M. Popovici, A. D. Stoica, an I. Ionita, "Optics of Curved-Crystal Neutron Spectrometers," informal notes (1987).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one (1.2MB) DOS diskette.

12. DATE OF ABSTRACT

December 1990.