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 energies >B C  Analysis of (α,γ), (α,n), and (α,p) reaction energies <B C

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)] ! ?

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) E  <12 MeV [Avrigeanu+, Nucl.Phys. A723,104(2003)] Phys.Rev C 73,038801(2006)] [Avrigeanu+, Phys.Rev C 73,038801(2006)]

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)

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 ]

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

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

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

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

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

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

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 E<20 MeV

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

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

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

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) ]

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

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

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

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

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

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

Marilena Avrigeanu28th Int. Workshop. on Nuclear Theory Rila Mountains 2009 α-particle elastic scattering & induced E<50 MeV V R = *Z/A 1/ / E 1/2 ROP: E 2 =0.9 B C a R = *Z/A 1/3 – 0.001*Z/A 1/3 E a R = *Z/A 1/3 + ( *Z/A 1/3 – )E E 2 < E<26.5 E>26.5 a R = *Z/A 1/3 – 0.001*Z/A 1/3 E 2 W D = EXTENDED

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

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

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. energies >B C  Description of (α,x) reaction cross energies ~ 8 energies ~ 8 MeV  α-nucleus OMP in the incident 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 !

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

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

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

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

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

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

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