18-Ar- 0 LLNL EVAL-Dec89 D.E.Cullen
UCRL-50400,Vol.31 DIST-MAY10 20100228
----JENDL-4.0 MATERIAL 1800
-----ELECTRO-ATOMIC INTERACTION DATA
The data were taken from EEDL.
The Livermore Evaluated Electron Data Library (EEDL) in the
ENDF-6 Format. Translated from the Livermore ENDL format
to the ENDF-6 Format by Bob MacFarlane (Los Alamos).
23/526 Elastic Scattering Cross Sections
23/527 Bremsstrahlung Cross Sections
23/528 Excitation Cross Sections
23/534 K (1S1/2) Electroionization Subshell Cross Sections
23/535 L1 (2s1/2) Electroionization Subshell Cross Sections
23/536 L2 (2p1/2) Electroionization Subshell Cross Sections
23/537 L3 (2p3/2) Electroionization Subshell Cross Sections
23/538 M1 (3s1/2) Electroionization Subshell Cross Sections
23/539 M2 (3p1/2) Electroionization Subshell Cross Sections
23/540 M3 (3p3/2) Electroionization Subshell Cross Sections
26/526 Elastic Scattering Angular Distributions
26/527 Bremsstrahlung Photon Energy Spectra and
Electron Average Energy Loss
26/528 Excitation Electron Average Energy Loss
26/534 K (1S1/2) Electroionization Subshell Energy Spectra
26/535 L1 (2s1/2) Electroionization Subshell Energy Spectra
26/536 L2 (2p1/2) Electroionization Subshell Energy Spectra
26/537 L3 (2p3/2) Electroionization Subshell Energy Spectra
26/538 M1 (3s1/2) Electroionization Subshell Energy Spectra
26/539 M2 (3p1/2) Electroionization Subshell Energy Spectra
26/540 M3 (3p3/2) Electroionization Subshell Energy Spectra
MF/MT combinations used to define ALL electron interaction data
are newly defined MF/MT numbers for ENDF/B-VI that did not exist
in earlier versions of ENDF/B.
Definition of Data
Cross Sections (MF=23)
1) The total electron interaction cross section is not given
explicitly; it is equal to the sum of the elastic scatter,
bremsstrahlung, excitation, and ionization cross sections,
i.e., MT = 526, 527, 528, and 534 through 572.
2) The total electroionization cross section is not given
explicitly; it is equal to the sum of the electroionization
subshell cross sections, i.e., all MT = 534 through 572.
Angular and Energy Distributions (MF=26)
3) For Elastic Scattering, the angular distribution of scattered
electrons is tabulated between cosine = -1.0 and +0.999999.
Between +0.999999 and +1.0 it is analytically defined as
d[Sig]/d(Cos) = A/[eta+(1.0 - Cos)]^2
where the shielding parameter (eta) is defined by Steve
Seltzer's expression (see, ref. 1), and the normalization (A)
is defined for continuity with the tabulated data at Cos =
+0.999999. Electron "elastic" scattering means no energy
loss, so only angular distributions are given.
4) For bremsstrahlung, both the outgoing electron and photon are
described. The photon energy spectra are given, but angular
distributions are not; these can be analytically defined by a
number of different methods. For the electron, average energy
loss is given. The electron is assumed to continue along its
original direction of travel, so angular distributions are not
given. WARNING - bremsstrahlung is a three body process,
involving an electron, a photon, and an atom - so that you
cannot use energy or momentum correlation to simply relate
the secondary electron and the emitted photon.
5) For excitation, the average energy loss of the electron is
given. The electron is assumed to continue along its original
direction of travel, so angular distributions are not given.
6) For Ionization, the spectra of electrons is given. The electron
is assumed to continue along its original direction of travel,
so angular distributions are not given. In ionization two
identical electrons emerge; the incident electron, and an
electron ejected by the atom [thereby ionizing the atom]. Since
the two particles are indistinquishable, we define the electron
with the lower energy to be that ejected by the atom, and the
electron with the higher energy to be the incident electron.
The energy of the two electrons is exactly correlated by energy
conservation: initial incident electron energy = binding energy
of the ejected electron, plus the kinetic energy of the ejected
and the secondary incident electron. Therefore only the spectra
of the lower energy, ejected electron is given. The energy of
the secondary incident electron should be defined to conserve
energy, as described above. The energy lost by the incident
electron is the sum of the binding and kinetic energy of the
7) Relaxation of ionized atoms back to neutrality is not described
here; it is described in the companion Evaluated Atomic Data
1) S.T. Perkins, D.E. Cullen, and S.M. Seltzer, "Tables and
Graphs of Electron-Interaction Cross Sections from 10 eV to
100 GeV Derived from the LLNL Evaluated Electron Data
Library (EEDL), Z = 1-100, UCRL-50400, Vol. 31, Lawrence
Livermore National Laboratory (1991).
2) D.E. Cullen "PROGRAM EPICSHOW: A Computer Code to Allow
Interactive Viewing of the EPIC Data Libraries" (Version
2000-1), UCRL-ID-1264455, Rev. 3, Part 4, Lawrence Livermore
National Laboratory (2000).
These are the primary references to the contents of this library
and they contains a complete list of references to the sources
of data used in this library, methods of evaluation, accuracy
of the data, etc.
(1) November, 1991 - Initial release in the ENDL format.
(2) October, 2001 - Initial release in the ENDF-6 format.