I just made a couple of "tri-layer" geo models for Penepma- thanks to Jon Wade!
They are 50 nm for the first layer (1st material), and 75 nm (and 30 nm) thick for the 2nd layer (2nd material) and then 1 cm of a 3rd material.
In my case, that 3rd material would be air at say 1 Pascal so I can model a thin film on a TEM "Smart Grid", from Dune Sciences, which come in 15, 30 and 75 nm thick SiO2 and Si3N4 back thinned TEM grids (for the 2nd layer).
http://www.dunesciences.com/This will allow us to deposit a thin film (here, Bi2Te3) directly on a back-thinned supporting structure to reduce continuum fluorescence and x-rays produced from substrate backscattered electrons.
We can't directly specify a three material input file in the Penepma12 GUI in Standard.exe, but all one needs to do is edit the input file using a text editor and add a third material (air at 1 Pascal, for example) to the material section and a step length for each layer (material).
So the input file created by the Penepma GUI outputs this using the default bilayer production files:
TITLE Tri-layer Thin Film On 1 Pascal Air X-ray Production Model
.
>>>>>>>> Electron beam definition.
SENERG 1.50E+04 [Energy of the electron beam, in eV]
SPOSIT 0.00E+00 0 1 [Coordinates of the electron source]
SDIREC 180 0 [Direction angles of the beam axis, in deg]
SAPERT 0 [Beam aperture, in deg]
.
>>>>>>>> Material data and simulation parameters.
Up to 10 materials; 2 lines for each material.
MFNAME Bi2Te3.MAT [Material file, up to 20 chars]
MSIMPA 1.0E+3 1.0E+3 1E+3 0 0 0 -1E+2 [EABS(1:3),C1,C2,WCC,WCR]
MFNAME SiO2.mat [Material file, up to 20 chars]
MSIMPA 1.0E+3 1.0E+3 1E+3 0 0 0 -1E+2 [EABS(1:3),C1,C2,WCC,WCR]
.
>>>>>>>> Geometry of the sample.
GEOMFN trilayer_50_75nm.geo [Geometry definition file, 20 chars]
DSMAX 1 1.0e-7 [IB, Maximum step length (cm) in body IB]
DSMAX 2 1.5e-7 [IB, Maximum step length (cm) in body IB]
.
>>>>>>>> Interaction forcing.
IFORCE 1 1 4 -10 0.1 1.0 [KB,KPAR,ICOL,FORCER,WLOW,WHIG]
IFORCE 1 1 5 -200 0.1 1.0 [KB,KPAR,ICOL,FORCER,WLOW,WHIG]
IFORCE 1 2 2 -10 1e-4 1.0 [KB,KPAR,ICOL,FORCER,WLOW,WHIG]
IFORCE 1 2 3 -10 1e-4 1.0 [KB,KPAR,ICOL,FORCER,WLOW,WHIG]
IFORCE 2 1 4 -10 0.1 1.0 [KB,KPAR,ICOL,FORCER,WLOW,WHIG]
IFORCE 2 1 5 -200 0.1 1.0 [KB,KPAR,ICOL,FORCER,WLOW,WHIG]
IFORCE 2 2 2 -10 1e-4 1.0 [KB,KPAR,ICOL,FORCER,WLOW,WHIG]
IFORCE 2 2 3 -10 1e-4 1.0 [KB,KPAR,ICOL,FORCER,WLOW,WHIG]
.
>>>>>>>> Emerging particles. Energy and angular distributions.
NBE 0 4e3 250 [E-interval and no. of energy bins]
NBTH 45 [No. of bins for the polar angle THETA]
NBPH 30 [No. of bins for the azimuthal angle PHI]
.
>>>>>>>> Photon detectors (up to 25 different detectors).
IPSF=0, do not create a phase-space file.
IPSF=1, creates a phase-space file.
.
PDANGL 45.0 55.0 0.0 360.0 0 [Angular window, in deg, IPSF]
PDENER 0 20e3 1000 [Energy window, no. of channels]
.
>>>>>>>> Job properties
RESUME dump1.dat [Resume from this dump file, 20 chars]
DUMPTO dump1.dat [Generate this dump file, 20 chars]
DUMPP 120 [Dumping period, in sec]
.
NSIMSH 2.0e+09 [Desired number of simulated showers]
TIME 100000 [Allotted simulation time, in sec]
And the input file after manual editing in a text editor looks like this:
TITLE Tri-layer Thin Film On 1 Pascal Air X-ray Production Model
.
>>>>>>>> Electron beam definition.
SENERG 1.50E+04 [Energy of the electron beam, in eV]
SPOSIT 0.00E+00 0 1 [Coordinates of the electron source]
SDIREC 180 0 [Direction angles of the beam axis, in deg]
SAPERT 0 [Beam aperture, in deg]
.
>>>>>>>> Material data and simulation parameters.
Up to 10 materials; 2 lines for each material.
MFNAME Bi2Te3.MAT [Material file, up to 20 chars]
MSIMPA 1.0E+3 1.0E+3 1E+3 0 0 0 -1E+2 [EABS(1:3),C1,C2,WCC,WCR]
MFNAME SiO2.mat [Material file, up to 20 chars]
MSIMPA 1.0E+3 1.0E+3 1E+3 0 0 0 -1E+2 [EABS(1:3),C1,C2,WCC,WCR]
MFNAME Air (1 Pascal).mat [Material file, up to 20 chars]
MSIMPA 1.0E+3 1.0E+3 1E+3 0 0 0 -1E+2 [EABS(1:3),C1,C2,WCC,WCR]
.
>>>>>>>> Geometry of the sample.
GEOMFN trilayer_50_75nm.geo [Geometry definition file, 20 chars]
DSMAX 1 1.0e-7 [IB, Maximum step length (cm) in body IB]
DSMAX 2 1.5e-7 [IB, Maximum step length (cm) in body IB]
DSMAX 3 1.5e-2 [IB, Maximum step length (cm) in body IB]
.
>>>>>>>> Interaction forcing.
IFORCE 1 1 4 -10 0.1 1.0 [KB,KPAR,ICOL,FORCER,WLOW,WHIG]
IFORCE 1 1 5 -200 0.1 1.0 [KB,KPAR,ICOL,FORCER,WLOW,WHIG]
IFORCE 1 2 2 -10 1e-4 1.0 [KB,KPAR,ICOL,FORCER,WLOW,WHIG]
IFORCE 1 2 3 -10 1e-4 1.0 [KB,KPAR,ICOL,FORCER,WLOW,WHIG]
IFORCE 2 1 4 -10 0.1 1.0 [KB,KPAR,ICOL,FORCER,WLOW,WHIG]
IFORCE 2 1 5 -200 0.1 1.0 [KB,KPAR,ICOL,FORCER,WLOW,WHIG]
IFORCE 2 2 2 -10 1e-4 1.0 [KB,KPAR,ICOL,FORCER,WLOW,WHIG]
IFORCE 2 2 3 -10 1e-4 1.0 [KB,KPAR,ICOL,FORCER,WLOW,WHIG]
.
>>>>>>>> Emerging particles. Energy and angular distributions.
NBE 0 4e3 250 [E-interval and no. of energy bins]
NBTH 45 [No. of bins for the polar angle THETA]
NBPH 30 [No. of bins for the azimuthal angle PHI]
.
>>>>>>>> Photon detectors (up to 25 different detectors).
IPSF=0, do not create a phase-space file.
IPSF=1, creates a phase-space file.
.
PDANGL 45.0 55.0 0.0 360.0 0 [Angular window, in deg, IPSF]
PDENER 0 20e3 1000 [Energy window, no. of channels]
.
>>>>>>>> Job properties
RESUME dump1.dat [Resume from this dump file, 20 chars]
DUMPTO dump1.dat [Generate this dump file, 20 chars]
DUMPP 120 [Dumping period, in sec]
.
NSIMSH 2.0e+09 [Desired number of simulated showers]
TIME 100000 [Allotted simulation time, in sec]
See attached geo files. Note that any geo files you create must have file names (not counting the extension) less than 16 characters for Penepma12 to read it properly.