Analysis of Alpha-Particle Elastic Scattering Experiments

McIntyre, John A.; Wang, K. H.; Becker, L.

doi:10.1103/physrev.117.1337

Cited by 161 publications

(54 citation statements)

References 7 publications

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“…to become unity for all large l values. This trend in phase shifts is very similar to that postulated in the modified Blair sharp cut-off model (McIntyre, Wang, and Becker 1960), the original extreme sharp cut-off model (Blair 1954) predicting an elastic differential cross section rather too oscillatory in nature. Figure 1 shows the best fit to the 10 MeV data obtained using the extreme semiclassical model with lmax.…”

Section: R-~-------------------------------------------'supporting

confidence: 81%

Carbon?Carbon Elastic Scattering

Bunyan¹

1962

Aust. J. Phys.

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Optical model analyses of elastic scattering of heavy ions have been carried out by Porter (1958) for nitrogen-nitrogen, and a preliminary study of the carbonnitrogen system has been made by Bassel, Melkanoff, and Drisko (Halbert, Hunting, and Zucker 1960). These analyses have shown that the optical model is capable of predicting, to a higher accuracy than the semiclassical models, the heavy ion elastic angular distributions. We have applied the optical model to the symmetrical carbon-carbon system using a Woods-Saxon potential in conjunction with a Coulomb potential modified to allow for the finite size of the interacting nuclei. The Woods-Saxon potential has the form where the interaction radius R is twice the nuclear radius roA 11 3 , and a is the diffuseness parameter. The numerical integration of the radial wave equation was carried out on the computer CSIRAC at the University of Melbourne.Calculations were made at both 10·0 and 12·5 MeV, the results at 10 MeV being given in Figure 1. The discrepancy at small angles is attributed to an uncertainty in experimental normalization (Bromley, Kuehner, and Almqvist 1961). The best fit to the elastic differential cross section was obtained for V=-25 MeV, W=-10MeV, a=0·6fermi, and r o =1·31 fermi. Calculations were also carried out for two other values of diffuseness and radius and for one other value of V and W. The results of the variation of diffuseness and radius are shown in Figure 1. Variation of these parameters had a marked effect on the differential cross section, whereas the values of V and W were of little importance. Decreasing the diffuseness had the expected result of raising the cross section due to reflection by the discontinuity in potential. Variation of ro, on the other hand, produced a change differing from that experienced in nucleon-nucleus scattering. The predominant effect in the elastic scattering of neutrons on increasing the radius is to move the whole diffraction pattern to smaller angles, whereas in the heavy ion case the whole diffraction pattern is lowered on increasing the radius. This lowering of the cross section is also accompanied by a very small shift to higher angles, in contrast with the nucleonnucleus case. Altering W from 10 to 15 MeV increased the scattering for angles larger than 55° by approximately 10%, whereas changing V from 25 to 30 MeV produced a decrease for angles larger than 40° of approximately 7 %. Thus the heavy ions cross section is dependent only on the " external" parameters, * Manuscript received

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Section: R-~-------------------------------------------'supporting

confidence: 81%

Carbon?Carbon Elastic Scattering

Bunyan¹

1962

Aust. J. Phys.

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“…Such effects may be described by a function defined by the Fourier transform of an absorptive shape function. In the presence of strong absorption, several theoretical investigations were based on numerical and analytical treatments of the partial wave expansion model for elastic scattering [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Most of these investigations showed clearly how sensitive the scattering data for strongly absorbed particles are to the detailed form of the scattering matrix around the grazing angular momentum.…”

Section: Introductionmentioning

confidence: 99%

Phenomenological analysis of elastic scattering reactions using different models

Badran¹,

Badahdah²

2009

Braz. J. Phys.

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McIntyre and Frahn-Venter three-parameter models are used to analyze the experimental data of three elastic scattering reactions α + 58 Ni, α + 116 Sn and α + 197 Au at the same incident energy of 240MeV. The different α-scattering cases have the same number of minima and maxima in their oscillatory structures of angular distribution. The increase in the mass of target nucleus leads to a smaller nuclear deflection minimum and causes the corresponding angular distribution to become smoother and with steeper slope. The Coulomb damping of Fraunhofer oscillations has an effect accompanied with the increase of mass of target nucleus. The presence of semi-classical phenomena such as Fresnel and Fraunhofer diffraction patterns etc., has been found by analyzing the experimental data of elastic scattering reactions, 16 O + 64 Zn, 32 S + 64 Ni, and 58 Ni + 27 Al at several laboratory energies. The generalised Fresnel model can fairly reproduce the angular distribution of these reactions. Excellent fitting can be obtained using Regge pole model, especially at backward angles where the data can not be recovered by the other three models. The adopted theoretical models can reasonably account for the general pattern of the data, thus allowing us to extract important parameters from elastic scattering processes. The analysis also shows that the total reaction cross section has an energy-dependent trend similar to that found by other models.

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“…The most natural and simple approximation for δ a (l) (or η (l)) and δ r (l) is a monotonically descending (for η (l), ascending to unity) function which can be easily modelled with help of, say, the Fermi-step or Gauss functions. For the case of elastic heavy-ion scattering at intermediate energies ( 20 MeV/nucleon), the S-matrix approaches of such a kind (see, e.g., [1], [2], [3], [4]) and the optical potential models which yield S (l) with such a behavior (see, e.g., [5], [6]) have appeared quite successful and argued for the so-called "rainbow" interpretation of the data. However, these models have not allowed the adequate description of all the features of the data measured.…”

Section: Introductionmentioning

confidence: 99%

Evolving model-free scattering matrix via evolutionary algorithm:O16-O16
Korda
¹
,
Molev
²
,
Korda
³

2005
Phys. Rev. C
13
0
1
0
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We present a new procedure which enables to extract a scattering matrix S (l) as a complex function of angular momentum directly from the scattering data, without any a priori model assumptions implied. The key ingredient of the procedure is the evolutionary algorithm with diffused mutation which evolves the population of the scattering matrices, via their smooth deformations, from the primary arbitrary analytical S (l) shapes to the final ones giving high quality fits to the data. Due to the automatic monitoring of the scattering matrix derivatives, the final S (l) shapes are monotonic and do not have any distortions.

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Analysis of Alpha-Particle Elastic Scattering Experiments

Cited by 161 publications

References 7 publications

Carbon?Carbon Elastic Scattering

Carbon?Carbon Elastic Scattering

Phenomenological analysis of elastic scattering reactions using different models

Evolving model-free scattering matrix via evolutionary algorithm:O16-O16
Korda
¹
,
Molev
²
,
Korda
³

2005
Phys. Rev. C
13
0
1
0
View full text Add to dashboard Cite

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Analysis of Alpha-Particle Elastic Scattering Experiments

Cited by 161 publications

References 7 publications

Carbon?Carbon Elastic Scattering

Carbon?Carbon Elastic Scattering

Phenomenological analysis of elastic scattering reactions using different models

Evolving model-free scattering matrix via evolutionary algorithm:O16-O16Korda1, Molev2, Korda3 2005Phys. Rev. C13010View full textAdd to dashboardCite

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Evolving model-free scattering matrix via evolutionary algorithm:O16-O16
Korda
¹
,
Molev
²
,
Korda
³

2005
Phys. Rev. C
13
0
1
0
View full text Add to dashboard Cite