(<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>t</mml:mi></mml:math>,<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">He</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>) Reaction on the Even Ni Isotopes

Blair, A.G.; Armstrong, D.D.

doi:10.1103/physrev.151.930

Cited by 131 publications

(21 citation statements)

References 20 publications

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“…This is what would be expected if dipole absorption proceeds through doorway states with a width of a few MeV. In view of the relative constancy of the product of the particle emission probability and the El-factor for the fv/2 nuclides, it is interesting to note the drastic difference between the products for d-wave protons proton hole is found at an excitation energy of 1.7 MeV in 58Ni [39] while, instead of being larger, it is at only 0.5 MeV in 63Cu [38], Provided the ds/2 proton particle states behave normally, one would therefore expect the differences between the P3/2 hole state and the ds/2 particle states to be appreciably smaller in 63Cu than in 58Ni. The (P3/2)-l(ds/2) +l state should therefore be found at a lower energy in 63Cu than in 58Ni, indicating that quite different parts of the corresponding resonances are excited in the two nuclides.…”

Section: Discussionmentioning

confidence: 77%

“…The energy levels and J~-assignments are from [40,45]. Spectroscopic factors are from [38] and those denoted by an asterisk are from [39] and Ep = 6.98 MeV are clearly seen in Fig. 4a.…”

Section: Sni( 7 P)57comentioning

confidence: 95%

“…Mairle et al [38] and Blair and Armstrong [39] disagree regarding the amount of fp=l pick-up. The (d, 3He)-results indicate a 58Ni ground state with a very small P3/2 proton admixture as shown in the weak {p= 1 pick-up to the (3/2-)1 state in 57Co at 1.38MeV (Ep=7.89MeV), while the (t, c0-reaction also shows a stronger #p=l transition to (3/2)2 at 1.76 MeV (Ep = 7.52 MeV) and therefore imply a larger P3/2 admixture.…”

Section: Sni( 7 P)57comentioning

confidence: 99%

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Proton hole states excited by monoenergetic gamma quanta

Wene¹

1975

Z Physik A

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Abstract.Earlier work has shown how information about the giant dipole resonance and proton hole states can be inferred from high resolution photoproton spectra obtained in irradiation with the 17.62 MeV gamma quanta produced by the ~Li(p, 7)SBe-reaction. To exploit this method the high energy photoproton spectra from 45Sc, 51V, 59Co, 5SNi, 63Cu and natural nickel have been measured with 60-120 keV resolution. The absolute cross sections for transitions to levels in the daughter nucleus have been determined. The results are compared with a simple model assuming a semidirect reaction proceeding via a dipole doorway state. Good correlation is found between the cross sections and the spectroscopic factors measured in proton pick-up reactions. Comparison with the total photoproton cross section for 5SNi indicates, however, that the majority of protons are emitted at lower energies from more complicated states.

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Section: Discussionmentioning

confidence: 77%

“…The energy levels and J~-assignments are from [40,45]. Spectroscopic factors are from [38] and those denoted by an asterisk are from [39] and Ep = 6.98 MeV are clearly seen in Fig. 4a.…”

Section: Sni( 7 P)57comentioning

confidence: 95%

Section: Sni( 7 P)57comentioning

confidence: 99%

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Proton hole states excited by monoenergetic gamma quanta

Wene¹

1975

Z Physik A

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“…The calculation for 'jlCo is performed by diagonali~ng HpTqM in the standard quasiparticle-phonon basis (-1)r'iJ5(2j+1)(2j'+i)~ '0 i_t)*j(Uj';p+Uj,Uj), (11) Here, c& is the particle creation operator; b,+ is the creation operator of the quadrupole phonon ; of is the occupation probability for the quasiparticle state l_j") and us = 1 -2:; ; fi = x,b,f b, and N is the maximum number of phonons included in the con~guration space. The parameter y0 stands for y0 = Ta (s-r), where To is the interaction strength and (s-i) is the average value of the energy denominators which in RPA correspond to the quasiparticle states 17) and 17).…”

Section: Energy Spectrummentioning

confidence: 99%

Study of proton-hole states in 61Co using the 62Ni(d, 3He)61Co reaction at 78 MeV

et al. 1984

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,The 6zNi(d,3He)61~o reaction was studied at a ~mbarding energy of 78 MeV. Angular distributions were measured in the range of B ,a& = 4.5" to X0. Energy levels up to 5.0 MeV excitation energy in "Co were studied. Exact finite-range DWBA calculations were employed to extract spectroscopic factors. Shell-model calculations were carried out in the truncated fp-model space. Qualitatively good agreement between theory and experiment is observed for the states based on fp components. In addition, calculations of the energy levels in 6'Co were performed in the SU(6) particlevibration model (PTQM). Spectroscopic factors have been calculated by using the PTQM transfer-o~rator form arising microscopically on the basis of RPA. This operator contains an additional term which has no counterpart in the interaction boson-fermion model (IBFM). Rather good agreement between theory and experiment was obtained. E NUCLEAR REACTION 62Ni(d, 3He), E = 78 MeV; measured u(E(3He)), a(@). '*Co deduced levels. DWBA analysis, shell-model, particle-vibration-model calculations.

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“…When direct decay occurs, the daughter nuclei should be left in proton hole states, since giant resonances are thought of being coherent superpositions of 1-particle-l-hole configurations. Proton hole states with spectroscopic factors not too low (~ 1/10 of the sum rule value 2j + 1) as known from 5SNi(d,3He) [13], 8~ [14] and 64Zn(d,3He) [15] are shown schematically in Fig.2, the most prominent of them represented by extended bars. In each case the observed non-statistical part closely resembles the features of the respective hole strength distribution: for the Co-Isotopes strength is concentrated in the lf7/2 ground state and a structure around 3 MeV (2sl/2, ld3/2), in S3Cn one observes a stronger fragmentation into various low lying states and a broad cluster of 2sl/2 and lf7/2 states centered at 4 MeV.…”

mentioning

confidence: 99%

Direct decay of the giant dipole resonance in58,60Ni and64Zn from (e, � c) experiments

Dolbilkin

Kondratiev

Lisin

et al. 1988

Z. Physik A - Atomic Nuclei

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(e,e'c) coincidence experiments at a momentum transfer of q=0.27 fm -I to study the decay of the giant dipole resonance in ss'soNi and S4Zn show deviations from photonuclear results and reveal strong contributions of direct decay to proton hole states.Since the discovery of the giant dipole resonance (GDR) photonuclear reactions have been the primary tool to study this collective E1 excitation in the nuclear continuum. The knowledge of its decay properties is still rather limited. Whereas in the (7,n)-rcaction thick targets may compensate for the low luminosity of monocnergetic photon beams, the information about charged decay channels obtained with continuous bremsstrahlung is impaired by the systematic errors intrinsic in this technique. Furthermore, very little is known about the final states populated by the decaying GDR. This knowledge is essential in order to distinguish statistical from dlrect decay, where the directly populated states reflect the microscopic structure of the collective mode. Electron scattering at low momentum transfer offers another fairly selective way for E1 excitation and the recent advent of cw electron accelerators has made possible the observation of their decay in coincidence experiments. Here we present (e,e'c) coincldence experiments concerned with the charged particle decay (c=p,a) of GDRs in medium heavy nuclei, comparing the semi-magic isotopes 5s's~ to the open shell nucleus S4Zn. So far the direct decay of the GDR in these nuclei has not been studied experimentally -as for the giant quadrupole resonance the situation is controversial [1,21. In order to keep the momentum transfer as low as q=0.27 fm -I, the cw electron beam of the Mainz microtron MAMI A was used with the reduced energy 137.2 MeV (current ~ 15 #A). Scattered electrons corresponding to excitation energies of E==8-25 MeV for ssNi and 12-25 MeV for S~ and 64Zn were measured at 23 ~ by the Mainz 180 ~ magnetic spectrometer with an energy resolution of < 10 -5. Charged decay products were detected in coincidence by six AE-E semiconductor telescopes (75 #m + 1500 #m, 16 msr), covering the angular range of 10~ Oc _< 210 ~ in 10~ relative to the q-axis at an azimuthal angle q%=45 ~ with respect to the scattering plane. An energy resolution of 300 keV was achieved for protons.The following discussion is based on measured (e,e'c) spectra, which have been 47r-integrated over | and iI%, assuming axial symmetry about the q-axis due to the dominance of longitudinal virtual photon polarization. Electron spectra taken in coincidence with protons and aparticles are shown in Fig.1 for all targets. Due to the coincidence condition, the elastic radiative background that dominates inclusive electron spectra is no longer present. An extrapolation from S4Zn(e,e'c) experiments at higher momentum transfers [3] leads to contributions of E2/E0 modes not exceeding 17% in the proton decay channd. They are stronger in the a-channel, but the (e,e'a) cross sections are generally small compared to the (e,e'p) yield and shall not be...

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(t,He4) Reaction on the Even Ni Isotopes

Cited by 131 publications

References 20 publications

Proton hole states excited by monoenergetic gamma quanta

Proton hole states excited by monoenergetic gamma quanta

Study of proton-hole states in 61Co using the 62Ni(d, 3He)61Co reaction at 78 MeV

Direct decay of the giant dipole resonance in58,60Ni and64Zn from (e, � c) experiments

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