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nat Mg(p,p) nat Mg cross-sections: benchmark experiment

nat Mg(p,p) nat Mg cross-sections: benchmark experiment. Chris Jeynes and Alex Gurbich University of Surrey Ion Beam Centre, Guildford Institute for Physics and Power Engineering, Obninsk. IAEA CRP on elastic scattering cross-sections for IBA 18-21 June 2007, Wien. Contents. Mg(p,p)Mg

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nat Mg(p,p) nat Mg cross-sections: benchmark experiment

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  1. natMg(p,p)natMg cross-sections: benchmark experiment Chris Jeynes and Alex Gurbich University of Surrey Ion Beam Centre, Guildford Institute for Physics and Power Engineering, Obninsk IAEA CRP on elastic scattering cross-sections for IBA 18-21 June 2007, Wien

  2. Contents • Mg(p,p)Mg • C(p,p)C example: C implant in Si • CuInAlSe/glass example: Na(p,p)Na??? • SigmaCalc O(a,a)O: bad at top of range? • Si(a,a)Si?? • H in GaN ERD: interference?

  3. Mg(p,p)Mg: measurement conditions • Bulk Mg sample • Multilayer Au/Mg/Au/Mg/Au/C sample

  4. Mg(p,p)Mg: high precision measurements Electronic gain determined for whole data set using PHD correction (Lennard): Gain uncertainty <0.1% Offset uncertainty ~600eV

  5. 1216keV Mg(p,p)Mg: data, theory & benchmark

  6. 1506 keV O O O 942.5 keV 1752 keV Mg(p,p)Mg, benchmark 942keV: shows resonance at 823keV 1506keV: shows resonance at 1483keV 1752keV: shows resonances at 1483keV and 1650keV (68TFU C & 800TFU MgO on surface)

  7. Mg(p,p)Mg, benchmark (multilayer sample)

  8. Mg(p,p)Mg, multilayer sample conclusions

  9. C O Mg 1483keV Mg 1630keV 1752keV H+ Q= 1720 EBS Elastic (non-Rutherford) BackScattering (Left) Spectrum of bulk magnesium with 68.1015 C/cm2 and 800.1015 MgO/cm2 on the surface (Below, left) SigmaCalc scattering cross-sections for natural Mg (the isotopes behave differently) at two different scattering angles (Below, right) Sharp resonance at 1483keV in more detail (FWHM 400eV)

  10. (1113±7).1015 C/cm2 30keV 5000C Mar06 data (TypeA uncertainty) E0 = 1730keV WDEPTH: Szilágyi++, NIM B100, 1995, 103 1% pileup in C: W&G NIM 133, 1976, 303 20nA, 100secs DataFurnace AUTOL option 4% effect: Gurbich++ NIM B190, 2002, 237 Resonance option 7% effect: Barradas++ NIM B247, 2006, 381

  11. Gurbich (SigmaCalc 2007): theta = 149.20 (lab) Bauman et al (1956): theta = 1560 (cm) EBS cross-sections

  12. Contents • The Inverse Problem in IBA (RBS/EBS/ERD/NRA) and Simulated Annealing (DataFurnace code) • Accurate Thin Film Depth Profiling in IBA • PIXE + particle scattering spectroscopies for depth profiling • Example 1: Pb glass standard – sanity check • Example 2: CuInAl thin films (photovoltaics) • Conclusions

  13. Mo Si CIS O In Se Cu Selenised CuInAl precursor, Mo electrode, glass substrate1554 KeV He RBS, 2070 keV H EBS glass CuInAlSe Mo Fit with Cu 31 In 23, Al 1, Se 46 RBS: unambiguous Cu:In:Se ratio EBS: Mo thickness (poor fit) But how much Al is there really?

  14. Selenised CuInAl precursor, Mo electrode, glass substrate1554 KeV He RBS, 2582 keV H RBS/EBS/PIXE Simultaneous self-consistent automatic fitting of RBS, EBS, and 3 * PIXE spectra = Cu 21 In 25, Al 6, Se 47 RBS: Cu:In:Se ratio EBS: Mo thickness PIXE: Al content (indirectly from the Si substrate signal): As & Fe also detected EBS RBS Glass CuInAlSe Mo 450 exit 250 exit 200 exit X-ray counts, log scale, red=data, blue=fit

  15. Gurbich (SigmaCalc 2007): theta = 149.20 (lab) Bauman et al (1956): theta = 1560 (cm) EBS cross-sections: Si & O from SigmaCalcEBS cross-sections: Na? ad hoc, & c.f. Al(p,p)Al! Na

  16. O Au Si Ni natSi(a,a)natSi, 16O(a,a)16O; 4018keV 4He EBS Blue data: theta=1500 Red data: theta=1700 O: SigmaCalc cross-sections Si: Leung 1972, theta=1650 O: Demarche & Terwagne 2006, 1700 Si: Leung 1972, modified>3870keV for theta=1500

  17. Surface H Surface H H in GaN: ERD interferences? 4018keV 4He 60keV H in Si ERD: 24um range foil, 300 scattering 60keV H in GaN: interference from 14N(a,p)17O?? Cross-sections only available for 1350

  18. Conclusions • Mg(p,p)Mg: • (i) High precision measurements 700keV - 1750keV with gain determined <0.1%; • (ii) SigmaCalc confirmed at 2.2% accuracy; • (iii) 1483keV resonance @400eV too narrow to determine directly: indirect thick film EBS works • C(p,p)C example: C implant in Si determined at <1% precision with SigmaCalc using DEPTH, W&G pileup, NDF AUTOL, NDF resonance • CuInAlSe/glass example: Na(p,p)Na needed! • SigmaCalc O(a,a)O: bad at top of range • SigmaCalc Si(a,a)Si needed • 60keV H in GaN (He ERD): interference from 14N(a,p)17O (no Xsections at forward angle!)

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