Target material file format


The material files specify chemical composition, density and atomic/molecular shell properties for the purpose of cross section and mean free path calculation.
The usual file name extension is .targ. Examples: an atom, a molecule, a mixture.
Several different versions of target material files exist, see the following descriptions.

File version 19990513

For TRAX version <= 0804, deprecated for newer versions.
   !filetype    trxtarg
   !fileversion <yyyymmdd>
   !filedate    <dow> <mmm> <dd> <hh>:<mm>:<ss> <yyyy>
   # 
   # Comment
   #
   !material      <name>
   [ !composition   <formula> ]
   [ !density       <rho / g/cm**3> ] 
   [ !molweight     <mol> ]
   [
   !shell
   <ne> <Ebind> <Eslater> [ <parentage1> [ <parentage2> ...] ]
   [
   <ne> <Ebind> <Eslater> [ <parentage1> [ <parentage2> ...] ]
   [
   ...
   ]
   ]
   ] 
The specification for one shell (primary quantum number) comprises the number of electrons, the experimental binding energy (keV), the mean kinetic energy according to Slater's rules (keV). Optionally, parentage information may be added which specifies how the molecular orbital may be composed of the contributing atomic orbitals using the LCAO (linear combination of atomic orbitals) method.
The parentage information is specified as follows:
   <parentage> = <element> <shell-number> <coefficient>
Composition, molweight and shell configuration may be omitted for builtin materials such as H2O and N2.
Molweight and shell configuration should be omitted for pure atoms since all elements up to Xe (currently) are already builtin.
For molecules a realistic shell configuration should be provided. Otherwise it will be built from the single contributing atoms.

File version 20020403

For TRAX version > 0804 and < 1312.
   !filetype    trxtarg
   !fileversion <yyyymmdd>
   !filedate    <dow> <mmm> <dd> <hh>:<mm>:<ss> <yyyy>
   # 
   # Comment
   #
   !material      <name>
   [
   !composition   <formula>
   ]
   !density       <rho / g/cm**3>
   [ !molweight     <mol> ]
   [
   !shells
   <cfg_1>, <ne_1>, <Ebind_1>, <Ekin_1>, <s_1>, [ <parentage_11> [ <parentage_12> ...] ]
   [
   <cfg_2>, <ne_2>, <Ebind_2>, <Ekin_2>, <s_2>, [ <parentage_21> [ <parentage_22> ...] ]
   ]
   ...
   ] 
The material name can be freely chosen, but must be uniqe.
The composition should be a plain chemical formula, e.g. NO2. The composition may be omitted if the material name is a decomposable chemical formula.
The molweight is optional (for backward compatibility), it is determined internally from the composition.
The specification for one shell comprises the atomic/molecular configuration (e.g. 1s, 2p1/2, etc.), number of electrons in the shell, the experimental binding energy (keV), the mean kinetic energy (keV) and the screening constant (e.g. according to Slater's rules). If the kinetic energy is omitted (e.g. by two adjacent commas) it will be estimated from the screening constant and the main quantum number derived from <cfg_2>.
For molecular targets parentage information may be added which specifies how the molecular orbital may be composed of the contributing atomic orbitals using the LCAO (linear combination of atomic orbitals) method.
The parentage information is specified as follows:
   <parentage> = <parent-element> <parent-cfg> <coefficient>
In any case, for molecules a realistic shell configuration should be provided. Otherwise it will be built from the single contributing atoms, which is not necessarily realistic.

File version 20131231

For TRAX version >= 1312

Adds support for Auger transitions by means of an extra section:

   !auger
   #<shell_1> <shell_2> <shell_3> <prob> <fyld>
   1 2 2 0.00435054 0.95812
   1 2 3 0.00661587 0.95812
where the <shell_i> describe the involved shells. <shell_1> denotes the ionized shell under consideration. The energy of the emitted Auger electron is evaluated as
   E = Ebind_1 - (Ebind_2-Ebind_3)  
<prob> denotes the probability of the respective transition and <fyld> its fluorescence yield.
Note that the shell numbers in the Auger specifications refer to the order in which the shells are specified in the preceeding section. Thus this order must never be changed, otherwise Auger transitions will be handled incorrectly.

TRAX versions >= 1312 come with a complete database of supported targets in the TARG subdirectory.

File version 20150823

For TRAX version >= 1312c

Adds support for excited states, denoted by occupation number zero, <ne_i>=0.


References


Last updated: M.Kraemer,
$Id: traxfmttarg.html,v 1.8 2016/01/11 17:12:12 kraemer Exp $