1. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 α - particle Optical Potential for astrophysical studies M. Avrigeanu and V. Avrigeanu "Horia Hulubei" National Institute for Physics & Nuclear Engineering, Bucharest, Romania α- OMP extended analysis: 50<A<209, E~8-50 MeV  Analysis of α elastic scattering angular distributions @ energies >B C  Analysis of (α,γ), (α,n), and (α,p) reaction data @ energies <B C

2. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 Marilena Avrigeanu2  -nucleus OMP: OPEN QUESTIONS  OMPs from ( ,  0 ) @ E  >80 MeV: DO NOT DESCRIBE (   ) @ E  <40 MeV [Nolte+, Phys. Rev. C 36, 1312 (1987)]  OMPs from (x,  ) @ E  <40 MeV: DO NOT DESCRIBE (α,α 0 ) reactions - astrophysical interest - applied interest: He damage effects [Avrigeanu+, Phys.Rev. C 49, 2136(1994)] [Avrigeanu+, Nucl.Phys. A764,246(2006)] ! ?

3. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 Marilena Avrigeanu3  -nucleus OMP: OPEN QUESTIONS  OMPs from ( ,  0 ) @ E  >80 MeV: DO NOT DESCRIBE (   ) @ E  <40 MeV [Nolte+, Phys. Rev. C 36, 1312 (1987)]  OMPs from (x,  ) @ E  <40 MeV: DO NOT DESCRIBE (α,α 0 ) reactions - astrophysical interest - applied interest: He damage effects [Avrigeanu+, Phys.Rev. C 49, 2136(1994)] [Avrigeanu+, Nucl.Phys. A764,246(2006)]  OMPs from ( ,  0 ) @ 13<E  <40 MeV: DO NOT DESCRIBE (  x) reactions @ E  <12 MeV [Avrigeanu+, Nucl.Phys. A723,104(2003)] Phys.Rev C 73,038801(2006)] [Avrigeanu+, Phys.Rev C 73,038801(2006)]

4. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 Nuclear Model Calculations OPTICAL MODEL : prime tool for all cross section calculations  Phenomenological OMP - still extensively used - while its uncertainties critically depend on: - particular alpha-nucleus system - incident energy - precision of analyzed data  Microscopic OPs: reduced uncertainties (e.g., OM ambiguities)  Pure elastic scattering OP analysis SCAT2 [O. Bersillon] - phenomenological OP + semi-microscopic (DF) OP (local version)  Coupled Reaction Channel (CRC) FRESCO-2003 [I.J. Thompson] - elastic transfer among weakly bound systems  Composite system equilibration - Geometry Dependent Hybrid (GDH) preequilibrium-emission model - Hauser-Feshbach (HF) statistical model  STAPRE-H95 [V. Avrigeanu, M. Avrigeanu] (updated)

5. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 Marilena Avrigeanu5 Microscopic Real Optical Potential [ M.A. et al. : Nucl. Phys. A 723 (2003)104 ]

6. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 At. Data Nucl. Data Tables 95 (2009) 501 50<A<124 α -particle elastic-scattering analysis to 50<A<124 @ E<50 MeV

7. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 7 DF-real & phenomenological imaginary potential for A~60 @ E<50 MeV U DF W V,W D

8. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 Phenomenological optical potential for E<30 MeV

9. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 Real Potential Volume Integral Marilena AvrigeanuRIPL-3, IAEA-Vienna, 10-14 December 20079

10. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 Marilena AvrigeanuRIPL-3, IAEA-Vienna, 10-14 December 200710 Local OMP parameter sets

11. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 Marilena Avrigeanu11 Local OMP parameter sets

12. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 ROP: (I) Settling OM-parametrization: α-particle elastic scattering ROP: (I) Settling OM-parametrization: α-particle elastic scattering @ E<20 MeV

13. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 α-particle elastic scattering & induced reactions @ E<50 MeV OMPs from (α,α 0 ) @ E α >B C (elastic scattering) DO NOT DESCRIBE (α,x) reactions @ E α <B C ROP: A<124 E 2 =0.9 B C

14. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 ROP: (II) Settling OM-parametrization: α-particle induced reactions at E<Bc

15. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 ROP: (II) Settling OM-parametrization: α-particle induced reactions at E<B c

16. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 ROP: (II) Latest check for α-particle induced reactions at E<B c (12 June 2009) [ ADNDT 95 (2009) 501; Phys.Rev. C 79 (2009) 027601 ]

17. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 At. Data Nucl. Data Tables 95 (2009) 501 50<A<124 Extension up to A=209 α -particle elastic-scattering analysis to 50<A<209 @ E<50 MeV

18. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 DF-real & phenomenological imaginary potential for A ≥ 132 @ E<30 MeV U DF W D & W V

19. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 Local OMP parameter sets: A>124

20. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 Phenomenological optical potential for A ≥ 132 @ E<30 MeV

21. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 α-particle elastic scattering & induced reactions @ E<50 MeV V R =41.75 + 0.7*Z/A 1/3 + 321/ E 1/2 ROP: E 2 =0.9 B C a R =0.631 + 0016*Z/A 1/3 – 0.001*Z/A 1/3 E a R =0.684 - 0016*Z/A 1/3 + (0.00026*Z/A 1/3 – 0.0026)E E 2 < E<26.5 E>26.5 a R =0.631 + 0016*Z/A 1/3 – 0.001*Z/A 1/3 E 2 EXTENDED

22. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 ROP - Extended ROP

23. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 α-particle elastic scattering & induced reactions @ E<50 MeV V R =41.75 + 0.7*Z/A 1/3 + 321/ E 1/2 ROP: E 2 =0.9 B C a R =0.631 + 0016*Z/A 1/3 – 0.001*Z/A 1/3 E a R =0.684 - 0016*Z/A 1/3 + (0.00026*Z/A 1/3 – 0.0026)E E 2 < E<26.5 E>26.5 a R =0.631 + 0016*Z/A 1/3 – 0.001*Z/A 1/3 E 2 W D =1.5+0.5 EXTENDED

24. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 EXTENDED ROP: (II) Settling OM-parametrization: σ( α,X) at E<B c

25. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 EXTENDED ROP: (II) Settling OM-parametrization: σ( α,X) at E<B c

26. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 Conclusions Conclusions Extension of  -nucleus OMP analysis below B C (α,α) data basis (α,x) data basis (α,α) data basis (α,x) data basis A=50-209, E~8-50 MeV A=50-209, E~8-50 MeV - comparison with BARC (2006) - comparison with BARC (2006)  Description of α elastic scattering a. d. @ energies >B C  Description of (α,x) reaction cross sections @ energies ~ 8 MeV @ energies ~ 8 MeV  α-nucleus OMP in the incident channel @ energies < B C - constant a R (E cm /B C ~0.9) ← (α,α) analysis - constant a R (E cm /B C ~0.9) ← (α,α) analysis - increasing W D from 0-4 MeV to W D (E cm /B C ~0.9) ← (α,α) analysis - increasing W D from 0-4 MeV to W D (E cm /B C ~0.9) ← (α,α) analysis Thank you !

27. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009

28. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009

29. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 Sensitivity to other model parameters: gamma parameterization

30. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009

31. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 Thank you !

32. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009

33. Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 Marilena AvrigeanuRIPL-3, IAEA-Vienna, 10-14 December 200733 OMPs describing  -emission: not suitable for  induced reactions ! ?