scholarly journals The 12C(a,g)16O Cross Section at Low Energies

1991 ◽  
Vol 44 (4) ◽  
pp. 369 ◽  
Author(s):  
FC Barker ◽  
T Kajino
Keyword(s):  
Cross Section ◽  
Ground State ◽  
State Transitions ◽  
Correct Treatment ◽  
R Matrix ◽  
A Value ◽  
S Factor ◽  
Low Energies ◽  
Cascade Transitions ◽  
Matrix Formula

An R-matrix formula for the cross section for radiative capture reactions is developed and applied to fit recently measured 12C(oc,y)160 data, for both ground-state transitions and cascade transitions through the 6�92 and 7 �12 MeV levels. The correct treatment of the channel contributions is significant for the E2 cascade transitions. Consistent fits of the cascade and ground-state data suggest a value of the channel radius larger than those previously used, and consequently a value of the low-energy astrophysical S-factor appreciably larger than that adopted recently.

THEORETICAL INVESTIGATIONS OF THE 12C(α,γ)16OE2 CROSS SECTION

2008 ◽  
Vol 17 (10) ◽  
pp. 2176-2181 ◽  
Author(s):  
MARIANNE DUFOUR ◽  
PIERRE DESCOUVEMONT
Keyword(s):  
Cross Section ◽  
Matrix Theory ◽  
Cluster State ◽  
Matrix Analysis ◽  
State Transitions ◽  
R Matrix ◽  
S Factor ◽  
Theoretical Investigations ◽  
Cascade Transitions ◽  
Asymptotic Normalization Constant

The E2 component of the 12 C (α,γ)16 O cross section is investigated in three ways: by a microscopic cluster model, by R-matrix fits and by a combination of both. The microscopic calculation leads to an estimate of the S-factor at a typical energy of 300 keV of SE2(300 keV )≈ 50 keV-b for ground-state transitions. Cascade transitions to the [Formula: see text] and [Formula: see text] excited states of 16 O are also studied. Then the S-factor is analyzed in the phenomenological R-matrix theory. We show that the background term plays a crucial role, and cannot be determined without ambiguity. Consequently only an upper limit on the extrapolated S-factor can be obtained [SE2(300 keV )< 190 keV-b ]. Finally, we use the microscopic Asymptotic Normalization Constant (ANC) of the [Formula: see text] level, well known to be a cluster state to constrain the R-matrix analysis. This procedure strongly reduces the uncertainties on the R-matrix fits, and we end up with a recommended value of SE2(300 keV ) = 42 ± 2 keV-b .

ESTIMATES OF THE ASTROPHYSICAL S-FACTORS FOR PROTON RADIATIVE CAPTURE BY 10B AND 24Mg NUCLEI USING THE ANCs FROM PROTON TRANSFER REACTIONS

2010 ◽  
Vol 19 (05n06) ◽  
pp. 1102-1108 ◽  
Author(s):  
S. V. ARTEMOV ◽  
S. B. IGAMOV ◽  
A. A. KARAKHODZHAEV ◽  
G. K. NIE ◽  
R. YARMUKHAMEDOV ◽  
...  
Keyword(s):  
Ground State ◽  
Radiative Capture ◽  
Transfer Reactions ◽  
Matrix Formalism ◽  
Zero Energy ◽  
Direct Capture ◽  
R Matrix ◽  
S Factor ◽  
Low Energies ◽  
Proton Transfer Reactions

The contribution of the direct radiative capture of protons by 10 B and 24 Mg nuclei at low energies to the astrophysical S -factors in the reactions 10 B (p,γ)11 C and 24 Mg (p,γ)25 Al have been calculated within the R-matrix formalism by using empirical proton asymptotical normalization coefficients (ANC). The ANCs for bound proton configurations {10 B +p} and {24 Mg +p} were obtained from the analysis of the reactions (3 He , d). The ANCs were also estimated from the values of the neutron ANCs in the mirror nucleus 25 Mg following the suggestion that the neutron and the proton in the mirror states have equivalent nuclear potentials. It has been found that the S -factor for the reaction 10 B (p,γ)11 C extrapolated to zero energy contributes ~100 keV b to the radiative capture to the ground state of 11 C . For the reaction 24 Mg (p,γ)25 Al the value S(0) gives 58 keV b with a direct capture contribution of 41 keV b .

scholarly journals Astrophysical S-factor of the radiative proton capture on 14C at low energies

2014 ◽  
Vol 29 (24) ◽  
pp. 1450125 ◽  
Author(s):  
Sergey Dubovichenko ◽  
Nasurlla Burtebaev ◽  
Albert Dzhazairov-Kakhramanov ◽  
Dilshod Alimov
Keyword(s):  
Ground State ◽  
Cluster Model ◽  
Phase Shift Analysis ◽  
Potential Cluster Model ◽  
Proton Capture ◽  
Position Location ◽  
Capture Reaction ◽  
Shift Analysis ◽  
S Factor ◽  
Low Energies

The phase shift analysis for position location of the [Formula: see text] resonance at 1.5 MeV was carried out on the basis of the known experimental measurements of the excitation functions of the p14 C elastic scattering at four angles from 90° to 165° and more than 100 energy values in the range from 600–800 keV to 2200–2400 keV. Also, the possibility to describe the available experimental data on the astrophysical S-factor for the proton capture reaction on 14 C to the ground state (GS) of 15 N at astrophysical energies was considered in the frame of modified potential cluster model (MPCM).

scholarly journals A REMARK ON GROUND STATE OF BOUNDARY IZERGIN–KOREPIN MODEL

2011 ◽  
Vol 26 (12) ◽  
pp. 1973-1989 ◽  
Author(s):  
TAKEO KOJIMA
Keyword(s):  
Ground State ◽  
Free Field ◽  
Baxter Equation ◽  
R Matrix ◽  
Free Field Realization ◽  
Matrix Formula ◽  
K Matrix

We study the ground state of the boundary Izergin–Korepin model. The boundary Izergin–Korepin model is defined by the so-called R-matrix and K-matrix for [Formula: see text] which satisfy Yang–Baxter equation and boundary Yang–Baxter equation. The ground state associated with identity K-matrix [Formula: see text] was constructed by W.-L. Yang and Y.-Z. Zhang in earlier study. We construct the free field realization of the ground state associated with nontrivial diagonal K-matrix.

Radiative capture of proton by 9Be(p, γ)10B at low energy.

2022 ◽  
Author(s):  
Abdul Kabir ◽  
Jameel-Un Nabi
Keyword(s):  
Cross Section ◽  
Capture Cross Section ◽  
Radiative Capture ◽  
Potential Model ◽  
Low Energy ◽  
Capture Cross ◽  
Zero Energy ◽  
R Matrix ◽  
S Factor ◽  
Radiative Capture Cross Section

Abstract Radiative capture p+9Be → 10B+γ at energies bearing astrophysical importance is a key process for the spectroscopic study of 10B. In this work, we consider the radiative capture cross-section for the 9Be(p, γ)10B within the framework of the potential model and the R-matrix method for the multi-entrance channel cases. In certain cases, when the potential fails, therefore, the R-matrix approach is better to use for the description of partial components of the cross-section that have sharp or broad resonances. For all possible electric and magnetic dipole transitions, partial components of the astrophysical S-factor are computed. The computed value of the total S-factor at zero energy is consistent with the reported results.

scholarly journals Calculation Of The 12C+a Capture Cross Section at Stellar Energies

1971 ◽  
Vol 24 (4) ◽  
pp. 771 ◽  
Author(s):  
FC Barker
Keyword(s):  
Cross Section ◽  
Capture Cross Section ◽  
Phase Shifts ◽  
Capture Cross ◽  
R Matrix ◽  
Channel Radius ◽  
S Factor ◽  
Scattering Phase ◽  
Scattering Phase Shifts

The 12C(0:, y) 160 cross section is calculated at stellar energies, using R-matrix parameters obtained by fitting consistently the 12C+", scattering phase shifts and the ",-spectrum from 16N f:l-decay. This limits the 12C+", channel radius to the range 5-7 fm. The S-factor at Eo< = 400 keV is calculated to lie in the range 0�05-0,33 MeV.b.

scholarly journals Corrigendum: Absolute Cross Sections of Proton Induced Reactions on 65Cu, 64Ni and 63Cu

1984 ◽  
Vol 37 (6) ◽  
pp. 709 ◽  
Author(s):  
ME Sevior ◽  
LW Mitchell ◽  
MR Anderson ◽  
CIW Tingwell ◽  
DG Sargood
Keyword(s):  
Statistical Model ◽  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
State Transitions ◽  
Measured Cross Section ◽  
Cross Section Data ◽  
Model Code ◽  
Section Data ◽  
Proton Induced Reactions

In the analysis of the 64Ni(p, y)65CU cross-section data (Fig. 2, p. 467), insufficient weight was placed on the influence of resonance to ground state transitions. When these transitions are properly taken into account, the measured cross section is increased by amounts varying from 5 % to 30 % for individual points. A plot of the revised data, together with the predictions of the statistical model code HAUSER*4 is now presented

Fine structure in the photoneutron spectra from praseodymium-141 and lead

1970 ◽  
Vol 48 (8) ◽  
pp. 950-953 ◽  
Author(s):  
K. G. McNeill ◽  
J. W. Jury ◽  
J. S. Hewitt
Keyword(s):  
Fine Structure ◽  
Excited State ◽  
Energy Spectrum ◽  
Cross Section ◽  
Ground State ◽  
Giant Dipole Resonance ◽  
Daughter Nucleus ◽  
State Transitions ◽  
Dipole Resonance ◽  
Section Curve

Careful measurements of the energy spectrum of photoneutrons ejected from praseodymium and from natural lead show that there are peaks on top of the expected smooth spectrum. Comparison with the recent cross-section studies, which indicate structure on the giant dipole resonance for these nuclei, shows agreement between the energies of the peaks found in the present work and the energies En = E−Qi where E corresponds to a peak in the cross-section curve and Qi is the threshold for producing a given state in the daughter nucleus. Only ground state transitions (for Pr) or ground state and the first two excited state transitions (for Pb) need be invoked.

Analysis of cross section and astrophysical S-factor at low energies

2013 ◽  
Author(s):  
Azni Abdul Aziz ◽  
Hasan Abu Kassim ◽  
Muhammad F. Zamrun
Keyword(s):  
Cross Section ◽  
S Factor ◽  
Low Energies
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