1. NAME AND TITLE OF DATA LIBRARY

ELAST2: Database of Cross Sections for the Elastic Scattering of Electrons and Positrons by Atoms.
 

2. NAME AND TITLE OF DATA RETRIEVAL PROGRAMS

Several programs are included; see section 7 below.
 

3. CONTRIBUTOR

National Institute of Standards and Technology, Department of Commerce, Gaithersburg, Maryland.
 

4. HISTORICAL BACKGROUND AND INFORMATION

The database presented in this package is an extension of the earlier database, "Elastic Scattering of Electrons and Positrons by Atoms: Database ELAST," Report NISTIR 5188, 1993. Cross sections for the elastic scattering of electrons and positrons by atoms were calculated at energies from 1 KeV to 100 MeV. Up to 10 MeV the RELEL code of Riley was used. Above 10 MeV the ELSCAT code was used, which calculated the factored cross sections and evaluates the screening factor Kscr in WKB approximation.
 

5. APPLICATION OF THE DATA

This database was developed to provide input for the transport codes, such as ETRAN, and includes differential cross sections, the total cross section, and the transport cross sections. In addition, a code TRANSX is provided that generates transport cross section of arbitrary order needed as input for the calculation of Goudsmit-Saunderson multiple-scattering angular distribution.
 

6. SOURCE AND SCOPE OF DATA

The database includes cross sections at 61 energies for electrons and 41 energies from positrons, covering the energy region from 1KeV to 100 MeV. The number of deflection angles included in the database is 314 angles. Total and transport cross sections are also included in this package. The data files have an extension jjj that represents the atomic number of the target atom.

The database includes auxiliary data files that enable the ELASTIC code to include the following optional modifications: (i) the inclusion of the exchange correction for electrons scattering; (ii) the conversion of the cross sections for scattering by free atoms to cross sections for scattering by atoms in solids; (iii) ti reduction of the cross sections at large angles and at high energies when the nucleus is treated as an extended rather than a point charge.
 

7. DISCUSSION OF THE DATA RETRIEVAL PROGRAM

The database of elastic-scattering cross sections can be accessed with the interpolation code ELASTIC. This is an interactive code that accesses the database and generates cross section tables at any desired set of energies between 1 KeV and 100 MeV, for any desired subset of the 314 deflection angles in the database. The following files may be required as input for ELASTIC: ANG.314, ESCAT.exe, PSCAT.exe, ESCAT.exe, ERSCAT.exe, PRSCAT.exe, EXRAT.exe, and ERAT31.exe and PRAT31.exe. The user must specify the output energy list and ratio of successive energies in the grid. The output files from ELASTIC can be further processed with the program TRANSX to obtain the generalized transport cross sections.

The RELEL code, originally developed on a main frame computer, was adopted here for use on a personal computer. When running the RELEL code, the user must supply a reference file that lists the other files used by the program. Several other programs are also included: ELSCAT, HANG1, HANGMOL1, HANGMUF1, HANGMUF2, ELINT3, GSCOFF3, GSDIS3, and VPOTX2. See the referenced report for explanations.
 

8. DATA FORMAT AND COMPUTER

ASCII card images, Personal Computers (D00208MNYCP00).
 

9. TYPICAL RUNNING TIME

Not noted.
 

10. REFERENCES

a) Documentation available with library:

M. J. Berger, and S. M. Seltzer, "Database of Cross Sections for the Elastic Scattering of Electrons and Positrons by Atoms," Report NISTIR 6573 (November 1, 2000).
 

b) Other useful documentation

M. J. Berger, S. M. Seltzer, R. Wang, and A. Schechter, "Elastic Scattering of Electrons and Positrons by Atoms: Database ELAST," Report NISTIR 5188 (1993).

M. J. Berger, S. M. Seltzer, "Electrons and Photons Transport Programs," NBS Report 9836 and 9837 (1968).

M. E. Riely, Relativistic, elastic electron scattering from atoms at energies greater than 1 KeV, Sandia Laboratory Report SLA-740-0107 (May 1974).

S. M. Seltzer, Applied Radiation and Isotopes, Vol 42, 917 (1991).

S. Goudsmit and J. L. Saunderson, Phys. Rev. Vol 57, 24 (1940).
 

11. CONTENTS OF LIBRARY

Included are the referenced document in (10.a) and one CD which includes the self-extracting archived data files and Fortran source codes written in a self-extracting compressed DOS file. The compressed file is about 52 MB. After file decompression, the size of the package is 149.3 MB including 1344 files.
 

12. DATE OF ABSTRACT

April 2001.
 

KEYWORDS: CHARGED PARTICLE CROSS SECTIONS; ELECTRON CROSS SECTIONS; POSITRON