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Proposal to the n_TOF Collaboration at CERN on IFIN-HH joining

n_TOF Collaboration Meeting 2006 Paris, Dec. 4- 5 , 2006. Proposal to the n_TOF Collaboration at CERN on IFIN-HH joining Activities at the neutron time of flight facility at CERN – Second Phase (n_TOF-Ph 2 ) http://pceet075.cern.ch/Documents/LoI_2005/n_TOF-Ph2_LoI.pdf.

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Proposal to the n_TOF Collaboration at CERN on IFIN-HH joining

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  1. n_TOF Collaboration Meeting 2006 Paris, Dec. 4-5, 2006 n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. Proposal to the n_TOF Collaboration at CERN on IFIN-HH joining Activities at the neutron time of flight facility at CERN – Second Phase (n_TOF-Ph2) http://pceet075.cern.ch/Documents/LoI_2005/n_TOF-Ph2_LoI.pdf Vlad Avrigeanu, Mihai Mirea “Horia Hulubei” National Institute for Physics & Nuclear Engineering, Bucharest, Romania http://tandem.nipne.ro/~Dante/, http://fp6.cordis.lu/fp6/partners INTEREST IN FURTHER MEASUREMENTS • Activation reactions: (n,p), (n,a), and (n,xc): V. Avrigeanu, M. Avrigeanu,R.A. Forrest (UKAEA-Culham) • α-particle optical model / nuclear matter density (T): M. Avrigeanu, V. Avrigeanu, W. von Oertzen (HMI-Berlin) • Measurements of fission cross-sections and neutron interferometry: M. Petrascu, A. Isbasescu, H. Petrascu, I. Tanihata (TRIUMF), W.Y. Lynch (MSU) • New information on the basic mechanism of nuclear fission: M. Mirea,L. Tassan-Got (IN2P3-Orsay)

  2. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. Spark for this IFIN-HH proposal Neutron capture cross section measurements for nuclear astrophysics at n_TOF Michael Heil on behalf of the n_TOF collaboration http://indico.cern.ch/getFile.py/access?contribId=270&sessionId=26&resId=1&materialId=slides&confId=059 Michael Heil NIC IX, June 2006, Geneva

  3. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. Outlook - Plan for measurements in Phase-2 n_TOF will continue: Letter of Intent signed by 24 research labs of the n_TOF Collaboration + 4 newcomers (January 2005) Spark for this FIN-HH proposal Michael Heil NIC IX, June 2006, Geneva

  4. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. Fast-neutron activation analysis (IFIN-HH, 2000-2006) • all stable 50,51V isotopes(+ EC/JRC/IRMM-Geel) • [Phys. Rev. C 65, 014604 (2001) ] • all stable 58,60,61,62,64Ni and 59Co isotopes (+ EC/JRC/IRMM-Geel) • [Nucl. Phys. A730, 255 (2004)] • all stable 92,94,95,96,97,98,100Mo isotopes (+ IRMM, KRI-St.Petersburg) • [Nucl. Phys. A705, 265 (2002)] [Phys. Rev. C 71, 044617(2005)] • all stable 180,182,183,184,186W isotopes (+ KRI, UKAEA, TUD-Dresden,[Nucl. Phys. A765, 1 (2006)]NRC-Petten, BNL-Brookhaven) • all stable174,176,177,178,179,180Hf, 181Ta isotopes (+ UKAEA, NRC, BNL) [PHYSOR-2006, …] • all stable55Mn, 63,65Cu isotopes (+ UKAEA, NRC, BNL)

  5. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. Outline of activation consistent model calculations [ E.D. Arthur – P.G. Young, LANL, ’80 ] [ IAEA/NDS RCs (12),Bucharest, 1982-2005] YES • unitary use of common model parameters for different mechanisms • use of consistent sets of input parameters - determined by analyses of various independent experimental data • unitary account of whole body of related experimental data for isotope chains and neighboring elements [ activation & particle-emission spectra ] [ enlarged incident-energy range ] n_TOF-Ph2 re-normalization or free parameters NO

  6. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. [ Isotopic effect on W isotopes: R. Caplar et al., Z. Phys. A 313, 227 (1983) ] e.g.: Isotopic effects in the (n,p) reaction cross section on Hf and W isotopes [Nucl. Phys. A765, 1 (2006)] Possible reason for actual model overestimation of 181Ta(n.p)181Hf data: • actual data: 181Ta(n.p)181gHf • unknown (long-life) isomer181mHf [PHYSOR-2006, D.10.2]

  7. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. Interest of reaction cross-sections analysis within energy range En<100 MeV: Comparison of measured and calculated 181Ta(p,xn) reaction cross sections Discrepant • Measured data ( if any! ) • Calculated cross sections • PE threshold in CP-induced reactions • e.g., H.C.Chiang+, Nucl.Phys. A340,466(1980): sPE ~ (1 - VC / E) • [ beff~ b(1 - VC / E)1/2 ]

  8. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec.

  9. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. BASIC QUESTIONS • NUCLEAR-SURFACE EFFECTS ? • in particle-hole level densities [PLD, CPCLibrary , Belfast, 1998]: • Phys. Rev. C 58, 295 (1998) • Comp. Phys. Comm. 112, 191 (1998) • in GDH model for pre-equilibrium emission [STAPRE-H95, NEA-DB,1995]: • J. Phys. G: Nucl. Phys. 20, 613 (1994) • Phys. Rev. C 65, 014604 (2001) • J. Nucl. Sci. Tech. Suppl. 2, 803 (2002) • NUCLEAR MOMENT OF INERTIA (I/Ir) ? • in nuclear level densities: [e.g., S.F. Mughabghab, C. Dunford: Phys. Rev. Lett. 82, 4083 (1998)] • J. Nucl. Sci. Tech. Suppl. 2, 746 (2002) • Nucl. Phys. A730, 255 (2004) • a-PARTICLE OPTICAL MODEL POTENTIAL • low-energy a-particle emission: • Nucl. Phys. A723, 104 (2003) • Nucl. Phys. A764, 246 (2006) • Phys. Rev. C 73, 038801 (2006)

  10. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. [Phys. Rev. C 65, 014604 (2001)] The only data The only D0data useful within this method I/Ir=0.75: describe bothneutron (RIPL) and protonD0data [ Cf: H. Weigmann et al., Nucl. Phys. A368,117(1981) ]

  11. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. • OMPs describinga-emission: not suitable for (a,a0) @ Ea~25 MeV ? !

  12. OMPs from (a,a0) (atEa<40 MeV): DO NOT DESCRIBE a-emission I I III BRUSLIB [www-astro.ulb.ac.be] n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec.

  13. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. Almost identicalat r >R7(surface tail region): • DF (2003) • ROP (2003) • McFadden-Satchler (1966) VR(R7)=-7 MeV[Fernandez-Blair, Phys.Rev. C 1,523(1970)] Surface tail: VR<10 MeV[Igo, Phys.Rev.Lett. 1,72(1958)] AHA (1994) [Ea<80 MeV] Larger aR-values:

  14. Additional usefulness for consistent description ofa-emission DF: ρ(r,T)= ρ0 / [1+exp[(r-c)/a]]γ γ=1, forT=0 γ<1, forT>0 n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec.

  15. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. High precision:uncertainties <3-4% (data basis average: ~15%) New opportunities also for model understanding New features of exp. data X5s

  16. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. International Symposium on Nuclear Astrophysics – Nuclei in the Cosmos–IX CERN, Geneva, 25-30 June, 2006 [ PoS (NIC-IX) ] 2006 2006 Present work: ‘cold’side 1994 2003

  17. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. • FISSION: UDERSTANDING THE FISSION MECHANISM / INVESTIGATION OF THE INTERMEDIATESTRUCTURE IN THE RESONANCE REGION (1/2) EXPLANATION OF Th ANOMALY / DYNAMICAL SINGLE-PARTICLE EFFECTS / ANGULAR DISTRIBUTION OF FISSION FRAGMENTS ISOTOPIC DISTRIBUTION OF FISSION PRODUCTS / IMPROVEMENT OF EVALUATIONS Fission single-particle level scheme DYNAMICAL SINGLE-PARTICLE EFFECTS Th anomaly (fine structure) PERFECT AGREEMENT

  18. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. FISSION: UDERSTANDING THE FISSION MECHANISM / INVESTIGATION OF THE INTERMEDIATESTRUCTURE IN THE RESONANCE REGION (2/2) EXPLANATION OF Th ANOMALY / DYNAMICAL SINGLE-PARTICLE EFFECTS / ANGULAR DISTRIBUTION OF FISSION FRAGMENTS ISOTOPIC DISTRIBUTION OF FISSION PRODUCTS / IMPROVEMENT OF EVALUATIONS Minimal action trajectory in a multidimensional configuration space 234U neutron induced cross section INTERMEDIATE RESONANCE STRUCTURE

  19. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. Fig.1. Schematic representation of collision 11Li + Si target Fig.2. Schematic representation of collision 11Li + C target One can see from Fig.1 and Fig. 2 that there is a marked difference In the screening between the Si and the C targets. In Table I it is shown that the two neutron pre-emission probability P{2}calculated by sharp-cutoff is 0.492 for C target and 0.144 for Si tar-get, that is by about 3.5 times larger for C target than for Si target.

  20. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. Fig. 1. This fig. is taken from ref. [1]. In the insert is shown the Cnn correlation function for 11Li calculated by using a 3-body model [1]. The minimum in the insert is due to the coherence bet-ween the 2 halo neutrons. In Table 3 it is shown that the new theory can be tested (Case 2) for a statistics of nn predicted in previous attached paper. [1] M.T.Yamashita et al., Phys. Rev. C72, 011601(R) (2005)

  21. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. Correlation Functions

  22. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec.

  23. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. SUMMARY PROPOSAL BASIS / INTEREST IN FURTHER MEASUREMENTS • Activation reactions: (n,p), (n,a), and (n,xc): V. Avrigeanu, M. Avrigeanu,R.A. Forrest (UKAEA-Culham) • α-particle optical model / nuclear matter density (T): M. Avrigeanu, V. Avrigeanu, W. von Oertzen (HMI-Berlin) • Measurements of fission cross-sections and neutron interferometry: M. Petrascu, A. Isbasescu, H. Petrascu, I. Tanihata (TRIUMF), W.Y. Lynch (MSU) • New information on the basic mechanism of nuclear fission: M. Mirea,L. Tassan-Got (IN2P3-Orsay)

  24. n_TOF Collaboration Meeting 2006, Paris, 4-5 Dec. Thank you - for kindest consideration & readiness to discuss our proposal - for invitation to attend n_TOF Meeting 2006 - for your attention !

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