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SIMNRA

Computer simulation of RBS, ERDA and NRA

by Matej Mayer

Max-Planck-Institut für Plasmaphysik

SIMNRA

Computer simulation of RBS, ERDA and NRA

by Matej Mayer

EXAMPLES

Some examples for the abilities of SIMNRA:

Backscattering with Non-Rutherford cross sections

2000 keV protons backscattered from carbon.
2000 keV protons backscattered from carbon, scattering angle 165°.
2000 keV protons backscattered from silicon.
2000 keV protons backscattered from silicon, scattering angle 165°.

ERDA with Non-Rutherford cross sections

ERDA with 2600 keV 4He incident ions for detection of H and D.
ERDA with 2600 keV 4He incident ions and dE-E telescope for detection of H and D. Both cross-sections are Non-Rutherford.

Multiple and plural scattering

500 keV 4He backscattered from 100 nm Au on Si, scattering angle 165°.
500 keV 4He backscattered from 100 nm Au on Si, scattering angle 165°. The background below the low energy edge of Au is due to plural large angle scattering, which is approximated in the dual scattering approximation by SIMNRA. The single scattering approximation, which is normaly used, fits the experimental data poorly. From [3].

Surface roughness

1.5 MeV 4He backscattered from a rough Ni-film on carbon.
1.5 MeV 4He backscattered from a rough Ni-film on carbon, scattering angle 165°. Mean Ni-film thickness 240 nm, FWHM of roughness 23 nm. The simulated spectrum of a smooth Ni-layer is shown for comparison. From [4].
2.0 MeV 4He backscattered from a rough oxidised Al-film on carbon.
2.0 MeV 4He backscattered from a rough oxidised Al-film on carbon, scattering angle 165°. The initial film was strongly eroded by plasma exposure, and some Ni was deposited. Mean film thickness 184 nm, FWHM of roughness 176 nm. Such extreme roughnesses cannot be described by smooth layers or diffusion profiles. From [4].
2.5 MeV protons backscattered from a 3.5 µm W-film on a rough carbon substrate.
2.5 MeV protons backscattered from 3.5 µm W-film on a rough carbon substrate, scattering angle 165°. The mean roughness of the carbon substrate was 8.2 µm. The simulated spectrum of a W-film on a smooth carbon substrate is shown for comparison. From [4].

Pile-up simulation

RBS spectrum of 2 MeV 4He on Au with pile-up
RBS spectrum of 2 MeV 4He on Au with pile-up, measured with a Canberra DSP 9660, PUR on, 6% dead time.