scholarly journals The 55Mn(p,?)56Fe and 55Mn(p,n)55Fe Cross Sections

1983 ◽  
Vol 36 (1) ◽  
pp. 1 ◽  
Author(s):  
LW Mitchell ◽  
DG Sargood
Keyword(s):  
Statistical Model ◽  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Reaction Rates ◽  
Significant Part ◽  
Thermonuclear Reaction ◽  
Model Calculations ◽  
The Cross

The cross section of the reaction 55Mn(p, y)56Pe has been measured in the energy range 0�80-2�04 MeV and of the reaction 55Mn(p, n)55Pe from threshold to 2� 04 MeV. Statistical model calculations reproduce the (p, n) cross section to within a factor of 1� 4, but with the (p, y) reaction they fail by a factor ;;;:2 over a significant part of the energy range. Thermonuclear reaction rates are calculated from the data for temperatures in the range (1-5) x 109 K.

scholarly journals Statistical model calculations of the 7Li +11 Β reaction

2019 ◽  
Vol 10 ◽  
pp. 165
Author(s):  
C. Tsabaris ◽  
C. T. Papadopoulos ◽  
R. Vlastou ◽  
A. A. Pakou ◽  
P. A. Assimakopoulos ◽  
...  
Keyword(s):  
Experimental Data ◽  
Statistical Model ◽  
Energy Range ◽  
Cross Section ◽  
Compound Nucleus ◽  
Cross Sections ◽  
Coulomb Barrier ◽  
Reaction Channel ◽  
Model Calculations ◽  
The Individual

The 7Li + 11 Β reaction has been studied in the energy range from a little below to about three times the Coulomb barrier by measuring the cross section of the 7- ray transitions in the residual nuclei produced. Statistical compound nucleus calculations have been performed in order to interpret the experimental data as well as to extract cross sections of the individual exit channels. The statistical compound nucleus theory can reproduce rather well the absolute j - ray and the various reaction channel excitation functions.

scholarly journals Thermonuclear Reaction Rates for Reactions Leading to N = 28 Nuclei

1995 ◽  
Vol 48 (1) ◽  
pp. 125
Author(s):  
A.J Morton ◽  
DG Sargood
Keyword(s):  
Statistical Model ◽  
Nuclear Reaction ◽  
Cross Sections ◽  
Optical Model ◽  
Reaction Rates ◽  
Reaction Cross ◽  
Model Parameters ◽  
Thermonuclear Reaction ◽  
Model Calculations ◽  
Reaction Cross Sections

Nuclear reaction cross sections derived from statistical-model calculations have been used in the calculation of thermonuclear reaction rates for 36 nuclei at temperatures that are representative of the interiors of evolving stars and supernovae as nucleosynthesis approaches the production of nuclei with N = 28. The statistical-model calculations used optical-model parameters in the particle channels which had been selected to give the best overall agreement between theoretical and experimental cross sections for reactions on stable target nuclei in the mass and energy ranges of importance for the stellar conditions of interest. The optical-model parameters used, and the stellar reaction rates obtained, are tabulated. Comparisons are made between these stellar rates and those from other statistical-model calculations in the literature.

45Sc(p, p')45Sc and the Attainment of a Thermal Distribution of States in an Astrophysical Environment

1981 ◽  
Vol 34 (1) ◽  
pp. 105 ◽  
Author(s):  
MR Anderson ◽  
SR Kennett ◽  
ME Sevior ◽  
DG Sargood
Keyword(s):  
Statistical Model ◽  
Energy Range ◽  
Excited States ◽  
Cross Section ◽  
Cross Sections ◽  
Model Calculations ◽  
Thermal Distribution ◽  
Model Cross Section ◽  
Superelastic Scattering ◽  
Good Agreement

Cross sections for inelastic scattering of protons by 45SC have been measured over the energy range Ep = 1?2-2? 5 MeV for protons leading to the second, third, fourth, sixth and eighth excited states of 45SC. Statistical model calculations are' in good agreement with the data. Further statistical model cross section calculations are used in an investigation of the part played by inelastic and superelastic scattering of protons in bringing about a thermal distribution of states in 45SCin a stellar interior under the conditions of explosive silicon burning. This mechanism is found to be effective for temperatures above 4? ?x 109 K

Cross sections and thermonuclear reaction rates for the 28Si(α, p)31P and 54Fe(α, p)57Co reactions

1984 ◽  
Vol 62 (2) ◽  
pp. 134-140 ◽  
Author(s):  
M. A. Buckby ◽  
J. D. King
Keyword(s):  
Statistical Model ◽  
Cross Sections ◽  
Ground State ◽  
Reasonable Agreement ◽  
Reaction Rates ◽  
Parametric Equation ◽  
Thermonuclear Reaction ◽  
Model Calculations ◽  
Experimental Cross

Absolute cross sections for the 28Si(α, p)31P and 54Fe(α, p)57Co reactions have been measured for laboratory bombarding energies over the range 5.52 ≤ Eα ≤ 12.00 MeV, using targets of approximately 4-keV thickness. Ground state reaction rates were then deduced from these cross sections and stellar rates were deduced by multiplying by the ratio of stellar-to-ground state rates obtained from statistical model calculations. Stellar rates for the reverse reactions have been determined and are fitted by a parametric equation for ease of interpolation. The experimental cross sections and rates have been compared with statistical model calculations and are in reasonable agreement for the 54Fe(α, p)57Co reaction but deviate by as much as a factor of three for the 28Si(α, p)31P reaction.

scholarly journals Statistical model calculations of 72,73Ge(n,p) and 72,74Ge(n,α) reactions on natural Ge

2020 ◽  
Vol 15 ◽  
pp. 104
Author(s):  
S. Galanopoulos ◽  
R. Vlastou ◽  
P. Demetriou ◽  
M. Kokkoris ◽  
C. T. Papadopoulos ◽  
...  
Keyword(s):  
Statistical Model ◽  
Energy Range ◽  
Neutron Energy ◽  
Cross Sections ◽  
Reaction Cross ◽  
Model Calculations ◽  
Monoenergetic Neutron ◽  
Theoretical Investigations ◽  
Equilibrium Emission ◽  
Reaction Cross Sections

Systematic experimental and theoretical investigations of the 72,73Ge(n,p)72,73 Ga and 72,74Ge(n,α)69,71Znm reaction cross sections are presented in the energy range from thresh- old to about 17 MeV neutron energy. The above reaction cross sections were measured from 8.8 to 11.4 MeV by using the activation method, relative to the 27Al(n,α)24Na refer- ence reaction. The quasi-monoenergetic neutron beams were produced via the 2H(d,n)3He reaction at the 5 MV VdG Tandem T11/25 accelerator of NCSR “Demokritos”. Statisti- cal model calculations using the code EMPIRE-II (version 2.19) taking into consideration pre-equilibrium emission were performed on the data measured in this work as well as on data reported in literature.

DOUBLE PION PHOTOPRODUCTION EXPERIMENT AT LNS–TOHOKU

2008 ◽  
Vol 23 (27n30) ◽  
pp. 2313-2316 ◽  
Author(s):  
◽  
H. KANDA ◽  
N. CHIGA ◽  
Y. FUJII ◽  
K. FUTATSUKAWA ◽  
...  
Keyword(s):  
Total Cross Section ◽  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Pion Photoproduction ◽  
Total Cross Sections ◽  
Free Proton ◽  
Double Pion ◽  
The Cross

The total cross sections for the π+π− photoproduction on the deuteron were measured in an energy range of 0.8 to 1.1 GeV. The obtained total cross section for the quasi-free π+π− photoproduction on the deuteron was about 60 % of those on the free proton. The cross section for Δ++Δ− photoproduction was derived from the non-quasi-free π+π− photoproduction events. It was smaller than the previous data.

Absolute cross sections for D2 Lyman and Werner band excitation by controlled electron impact

1984 ◽  
Vol 62 (1) ◽  
pp. 1-9 ◽  
Author(s):  
K. Becker ◽  
J. W. McConkey
Keyword(s):  
Energy Range ◽  
Electron Impact ◽  
Cross Section ◽  
Cross Sections ◽  
Impact Energy ◽  
Emission Cross Section ◽  
Direct Excitation ◽  
The Cross ◽  
Impact Energies

We have studied the Lyman [Formula: see text] and Werner [Formula: see text] band emissions produced by 20–500-eV electrons incident on molecular deuterium, D2. Emission cross sections of (3.7 ± 0.9) × 10−17 cm2 for the B → X and (3.54 ± 0.74) × 10−17 cm2 for the C → X system have been determined at 100-eV impact energy. Cascading did not play an important role in the [Formula: see text] emission, but it was shown to affect the [Formula: see text] emission seriously, particularly for impact energies below 50 eV. We estimate the cross section for direct excitation of the [Formula: see text] state and the cascade cross section to be 2.95 × 10−17 and 0.75 × 10−17 cm2, at 100 eV respectively. The cascade cross section is 20 ± 10% of the total B → X emission cross section, and is essentially constant in the energy range 300–50 eV, but increases significantly for lower impact energies, e.g., to 40 ± 15% at 27.5 eV. The cross section for the atomic 2p → 1s Lyman α emission from D2 has also been measured and the value of 1.00 × 10−17 cm2 at 100 eV is 20% smaller than the cross section for Lyman α emission from H2.

Excitation of singly-ionized barium ions by electron impact

1970 ◽  
Vol 48 (3) ◽  
pp. 275-278 ◽  
Author(s):  
J. Davis ◽  
S. Morin
Keyword(s):  
Energy Range ◽  
Electron Impact ◽  
Cross Section ◽  
Cross Sections ◽  
Experimental Measurements ◽  
Barium Ions ◽  
Semiclassical Method ◽  
The Cross

We present cross-section calculations for excitation of singly-ionized barium ions by electron impact over the energy range from 3 to 100 eV. The cross sections were evaluated using Burgess' semiclassical method. Finally, our predictions are compared with two other current techniques and some recent experimental measurements. The agreement was found to be good.

PECULIARITIES OF NUCLEAR REACTIONS INDUCED BY 6He AND 6Li NUCLEI NEAR THE COULOMB BARRIER

2008 ◽  
Vol 17 (10) ◽  
pp. 2349-2353 ◽  
Author(s):  
YU. E. PENIONZHKEVICH ◽  
R. KALPAKCHIEVA ◽  
A. A. KULKO ◽  
S. M. LUKYANOV ◽  
V. A. MASLOV ◽  
...  
Keyword(s):  
Statistical Model ◽  
Cross Section ◽  
Coulomb Barrier ◽  
Nuclear Reactions ◽  
Transfer Reactions ◽  
Excitation Functions ◽  
Model Calculations ◽  
The Cross ◽  
Evaporation Residues

Excitation functions for evaporation residues in the reactions 206,208 Pb (6,4 He,2n 210 Po , as well as for the transfer reactions in the interaction of 6 He and 6 Li projectiles with Au and Pt were measured at the energies near the Coulomb barrier. Studied reactions were characterized by an increase in the cross-section compared to statistical model calculations.

scholarly journals A systematic study of proton capture reactions in the Se-Sn region relevant to p-process nucleosynthesis

2019 ◽  
Vol 11 ◽  
Author(s):  
S. Harissopulos ◽  
P. Demetriou ◽  
S. Galanopoulos ◽  
G. Kriembardis ◽  
M. Kokkoris ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Nuclear Physics ◽  
Nuclear Reactions ◽  
Reaction Network ◽  
Reaction Rates ◽  
Compton Suppression ◽  
Experimental Information ◽  
Systematic Investigation ◽  
Model Calculations

The synthesis of the so-called ρ nuclei, i.e. a certain class of proton rich nuclei that are heavier than iron, requires a special mechanism known as ρ process. This process consists of various nucleosynthetic scenaria. In some of them proton and alpha-capture reactions are strongly involved, p-process nucleosynthesis is assumed to occur in the Oxygen/Neon rich layers of type II supernovae during their explosion, ρ nuclei are typically 10-100 times less abundant than the corresponding more neutron-rich isotopes. The prediction of their abundances is one of the major puzzles of all models of p-process nucleosynthesis. Until now all these models are capable of reproducing these abundances within a factor of 3. However, they all fail in the case of the light ρ nuclei with A<100. The observed discrepancies could be attributed to uncertainties in the pure "astrophysical" part of the p-process modelling. However, they could also be the result of uncertainties in the nuclear physics data entering the corresponding abundance calculations. In order to perform these calculations the cross sections of typically 10000 nuclear reactions of an extended reaction network involving almost 1000 nuclei from A=12 to 210 are used as input data. Such a huge amount of experimental cross section data are not available. Hence, all extended network calculations rely almost completely on cross sections predicted by the Hauser-Feshbach (HF) theory. It is therefore of paramount importance, on top of any astrophysical model improvements, to test also the reliability of the HF calculations, i.e. to investigate the uncertainties associated with the evaluation of the nuclear properties, like nuclear level densities and nucleon-nucleus potentials, entering the calculations. Until now, this check has been hindered significantly by the fact that in the Se-Sn region there has been scarce experimental information on cross sections at astrophysically relevant energies. In the present work, a systematic investigation of (p,7) cross sections of nuclei from Se to Sb is presented for the first time. The in-beam cross section measurements reported were carried out at energies relevant to p-process nucleosynthesis, i.e. from 1.4 to 5 MeV. The experiments were performed by using either an array of 4 HPGe detectors of 100% relative efficiency shielded with BGO crustals for Compton suppression, or a 4π Nal summing detector. The resulting cross sections, astrophysical S-factors and reaction rates of more than 10 nuclear reactions are compared with the predictions of various statistical model calculations.

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