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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

CROSS-SECTION DATA

SIMNRA and cross-section data from IBANDL

The Nuclear Data Section of the International Atomic Energy Agency (IAEA) has created a Web-site with cross section data for non-Rutherford backscattering and nuclear reactions: The Ion Beam Analysis Nuclear Data Library (IBANDL) at http://www-nds.iaea.org/ibandl/. This library contains many additional cross-section data, which are not yet included in SIMNRA. If you don't find a cross section you need in SIMNRA or on this page, it is worth looking in IBANDL.

IBANDL is actively being developed, as is the R33 file format for the cross-section data: this format is steadily being extended, sometimes resulting in compatibility problems between IBANDL and SIMNRA. Please report incompatible files, both to the SIMNRA author and to IBANDL.

There is a compatibility problem between SIMNRA 5.0 and some files in IBANDL. This problem has been fixed in SIMNRA 5.02. Another compatibility problem between all SIMNRA versions and some files in IBANDL was introduced at the end of the year 2008. This problem has been fixed in SIMNRA 6.05. Use SIMNRA 6.05, if you are using files from IBANDL. A bug fix for SIMNRA 5.0x is not available. Please upgrade to SIMNRA 6.05, if you are using any earlier SIMNRA version.

SIMNRA and SigmaCalc

SigmaCalc is a program which provides evaluated (recommended) differential cross section data for ion beam analysis. SigmaCalc was created by A. Gurbich and is hosted by the Nuclear Data Section of the International Atomic Energy Agency (IAEA). The cross-section data calculated by SigmaCalc are in R33 format and can be used by SIMNRA. Their use is highly recommended. The data are not distributed with SIMNRA due to copyright reasons. The data files have to be obtained from http://www-nds.iaea.org/sigmacalc/.

Discussion

This section reviews existing cross section data and gives some recommendations which cross section data files should be used.

Backscattering of protons from D

File Source
Langley R33 HD165_Langley.r33 Langley (1976)
Langley RTR PH_LA76A.rtr Langley (1976)
Backscattering cross sections of protons from deuterium
Fig. 1: Backscattering cross sections of protons from D, experimental data by Langley.

Available cross-sections for backscattering of protons from D are listed above and shown in Fig. 1. Both data sets were digitised from the same publication by Langley, where he showed the same data in mb/sr in the center-of-mass system and as ratio-to-Rutherford in the laboratory system. Unfortunately, these data disagree by a factor of about 4. The file PH_LA76A.rtr relies on the published ratio-to-Rutherford values (these data are also shown in the Tesmer/Nastasi book), while the file HD165_Langley.r33 relies on the published mb/sr values. A similar uncertainty is present for the scattering angle, which is described as 165° center-of-mass angle (equals to 151° lab angle) in one publication, and as 165° lab angle in another publication. According to our experience with deuterated amorphous hydrocarbon layers the cross section in the file HD165_Langley.r33 seems to be correct, while the data in PH_LA76A.rtr are much too low. A laboratory scattering angle of 165° seems to be more likely than 165° center-of-mass angle.

Recommended cross section data for D: HD165_Langley.r33, likely for 165° lab angle.

Backscattering of protons from C at 165° - 170°

File Source
Amirikas 170° PC_AM93A.rtr Amirikas (1993)
Amirikas Fit 170° 12CPPC_2.r33 Amirikas (1993)
Mazzoni 170° HC170_Mazzoni.r33 Mazzoni (1998)
Erratum Mazzoni (1999)
Liu 170° PC_LI93C.rtr Liu (1993)
Rauhala 170° PC_RA85A.rtr Rauhala (1985)
Jackson 168.2° PC_JA53A.rtr Jackson (1953)
Amirikas Fit 165° 12CPPC.r33 Amirikas (1993)
Mazzoni 165° HC165_Mazzoni.r33 Mazzoni (1998)
Erratum Mazzoni (1999)
Gurbich 165° HC165_Gurbich.r33 Gurbich (2002)
private communication, based on Gurbich (1998)
Backscattering cross sections of protons from C Backscattering cross sections of protons from C (magnification)
Fig. 2: Backscattering cross sections of protons from C at 165° - 170°. Top: 300 - 4500 keV; Bottom: Magnification of the range 300 - 3000 keV. Dots: Experimental data; Lines: Fit to experimental data or theoretical result.

Available cross-sections for backscattering of protons from C are shown in Fig. 2. The data by Jackson were digitized from the original publication and suffer from large digitizing errors - use of these data should be avoided. The Amirikas 170° data have a tendency to be lower than all other data. Amirikas Fit 170° is a fit to the Amirikas 170° data, the fit is published in the original publication. The quality of the fit is not too good, and deviations up to 10% between the measured data and the fit to them are observed. Amirikas Fit 165° was obtained by interpolating the fits at 150° and 170°. The accuracy of this interpolation cannot be better than the accury of the original fits. The Liu 170° have a tendency to be higher than all other data, especially at the maximum of the resonance. The Rauhala and Mazzoni data show good agreeement, but the energy step width of the Mazzoni data is smaller, thus showing a better coverage of the energy range. The Gurbich data were calculated with SigmaCalc by fitting a nuclear model to all existing experimental data. These data are the most reliable. The data set for 165° is included in SIMNRA, data for different angles can be calculated and downloaded from SigmaCalc.

Recommended cross section data for C: Gurbich for 165° is already included in SIMNRA.  For all other angles: Calculate and download the cross-section data from SigmaCalc.

Backscattering of protons from N at 165° - 178°

File Source
Ramos 178° HN178_Ramos.r33 Ramos (2002)
Rauhala 170° PN_RA85A.rtr Rauhala (1985)
Guohua 170° HN170_Guohua.r33 Guohua (1991)
Olness 167° PN_OL58A.rtr Olness (1958)
Lambert 165° PN_LA67B.rtr Lambert (1967)
Backscattering cross sections of protons from N at 165° - 178° Backscattering cross sections of protons from N at 165° - 178° (magnification)
Fig. 3: Backscattering cross sections of protons from N at 165° - 178°. Top: 500 - 4100 keV; Bottom: Magnification of the range 500 - 3100 keV. All data are experimental data.

Available cross-sections for backscattering of protons from N at 165° - 178° are shown in Fig. 3, and in Fig. 4 at 140° - 159°. The data show a large scatter, and agreement between different authors is poor. Recommended cross-section data are available from SigmaCalc. These are not included in the SIMNRA distribution.

Recommended cross section data for N: Calculate and download the cross-section data from SigmaCalc.

Backscattering of protons from N at 140° - 159°

File Source
Bashkin 159° PN_BA59A.rtr Bashkin (1959)
Lambert 155° PN_LA67A.rtr Lambert (1967)
Hagedorn 152° PN_HA57E.rtr Hagedorn (1957)
Tautfest 150° PN_TA56A.rtr Tautfest (1956)
Ramos 140° HN140_Ramos.r33/td> Ramos (2002)
Backscattering cross sections of protons from N at 140° - 159° Backscattering cross sections of protons from N at 140° - 159° (magnification)
Fig. 4: Backscattering cross sections of protons from N at 140° - 159°. Top: 500 - 4100 keV; Bottom: Magnification of the range 500 - 3100 keV. All data are experimental data.

Available cross-sections for backscattering of protons from N at 140° - 159° are shown in Fig. 4, and in Fig. 3 for 165° - 178°. The data show a large scatter, and agreement between different authors is poor. Recommended cross-section data are available from SigmaCalc. These are not included in the SIMNRA distribution.

Recommended cross section data for N: Calculate and download the cross-section data from SigmaCalc

Backscattering of protons from O at 165° - 178°

File Source
Ramos 178° HO178_Ramos.r33 Ramos (2002)
Amirikas 170° PO_AM93A.rtr Amirikas (1993)
Gurbich 170° (digitised) 16OPPO.r33 Gurbich (1997)
Gurbich 165° HO165_Gurbich.r33 Gurbich (2002)
private communication, based on Gurbich (1997)
Backscattering cross sections of protons from O

Backscattering cross sections of protons from O (magnification)

Fig. 5: Backscattering cross sections of protons from 16O at 165° - 178°. Top: Full range; Bottom: Magnification for better visibility. Dots: Experimental data; Lines: Theoretical results.

Available cross-sections for backscattering of protons from O are shown in Fig. 5. The data in 16OPPO.r33 were digitised from the original publication and suffer from large digitising errors at energies above 3300 eV - use of these data should be avoided. The data by Amirikas show some scatter, but are in good agreement with the data by Ramos. The Gurbich 165° data were calculated with SigmaCalc by fitting a nuclear model to all existing experimental data. These data are the most reliable.

Recommended cross section data for O: The file HO165_Gurbich.r33 (Gurbich for 165°) is already included in SIMNRA. For all other angles: Calculate and download the cross-section data from SigmaCalc

Backscattering of protons from Al

File Source
Chiari 140° HAl140_Chiari.r33 Chiari (2001)
Ramos 140° HAl140_Ramos.r33 Ramos (2002)
Chiari 170° HAl170_Chiari.r33 Chiari (2001)
Rauhala 170° PALRA89A.rtr Rauhala (1989)
Backscattering cross sections of protons from Al at 140° Backscattering cross sections of protons from Al at 170°
Fig. 6: Backscattering cross sections of protons from Al at 140° and 170°. All data are experimental data.

Available cross-sections for backscattering of protons from Al are shown in Fig. 6. The data by Rauhala, Chiari and Ramos show good quantitative agreement. However, the step width of the Rauhala data is larger, and the fine structure of the cross section is less well resolved than by Chiari. The height of the resonances is smaller in the Ramos data, which may be due to the use of a thicker target. It should be noted that according to theoretical calculations (A.F. Gurbich et al., Nucl. Instr. Meth. B190 (2002) 237) the backscattering cross section has many narrow resonances, which are not resolved in any of the existing data. Recommended cross-section data are available from SigmaCalc. These are not included in the SIMNRA distribution.

Recommended cross section data for Al: Calculate and download the cross-section data from SigmaCalc.

Backscattering of protons from Si at 160° - 170°

File Source
Amirikas 170° PSiAM93A.rtr Amirikas (1993)
Amirikas Fit SippSi.rtr Amirikas (1993) 
Fit formula for 170°
Rauhala 170° PSiRA85A.rtr Rauhala (1985)
Vorona 167.2° PSiVO59A.rtr Vorona (1959)
Salomonovic 160° HSi160_Salomonovic.r33 Salomonovic (1993)
Salomonovic 170° HSi170_Salomonovic.r33 Salomonovic (1993)
Gurbich 165° HSi165_Gurbich.r33 Gurbich (2002)
private communication, based on Gurbich (1998)
Backscattering cross sections of protons from Si
Fig. 7: Backscattering cross sections of protons from Si at 160° - 170°. Dots: Experimental data; Lines: Fit to experimental data or theoretical result.

Available cross-sections for backscattering of protons from Si are shown in Fig. 7 . The Amirikas 170° data have a tendency to be lower than other data, and they stay below the Rutherford cross-section at low energies. Amirikas Fit is a fit to the Amirikas 170° data, the fit is published in the original publication. The quality of the fit is not too good, and deviations up to 10% between the measured data and the fit to them are observed. The Vorona data have a tendency to be higher than all other data, but generally agree well with the Rauhala and Salomonovic data. The Gurbich data were calculated with SigmaCalc by fitting a nuclear model to all existing experimental data. These data are the most reliable.

Recommended cross-section data for Si: The file HSi165_Gurbich.r33 (Gurbich for 165°) is already included in SIMNRA.  For all other angles: Calculate and download the cross-section data from SigmaCalc.