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

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 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 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.

scholarly journals Isomeric cross section study of neutron induced reactions on Ge isotopes

2020 ◽  
Vol 239 ◽  
pp. 01028
Author(s):  
R. Vlastou ◽  
A. Kalamara ◽  
G. Gkatis ◽  
A. Stamatopoulos ◽  
M. Kokkoris ◽  
...  
Keyword(s):  
Statistical Model ◽  
Cross Section ◽  
Cross Sections ◽  
Residual Nucleus ◽  
Activation Technique ◽  
Flux Variation ◽  
Model Calculations ◽  
Neutron Beams ◽  
Hpge Detectors ◽  
Empire Code

Cross sections for the 70,76Ge(n,2n), 72,73Ge(n,p) and 72,74Ge(n, α) reactions have been measured at the 5.5 MV tandem T11/25 Accelerator Laboratory of NCSR Demokritos, using the activation technique. Neutron beams have been produced in the ~16-20 MeV energy region, by means of the 3H(d,n)4He reaction. The maximum flux has been determined to be of the order of 105 n/cm2 s, while the flux variation of the neutron beam was monitored by using a BF3 detector. The cross section has been deduced with respect to the 27Al(n, α)24Na and 93Nb(n,2n)92mNb reference reactions. The contaminations from reactions induced on neighboring Ge isotopes and leading to the same residual nucleus, have been taken into account. After the end of the irradiations, the activity induced by the neutron beams at the targets and reference foils, has been measured by HPGe detectors. Statistical model calculations using the EMPIRE code were performed on the data measured in this work as well as on data reported in literature.

scholarly journals Effect of Excited States on Thermonuclear Reaction Rates

1983 ◽  
Vol 36 (4) ◽  
pp. 583 ◽  
Author(s):  
DG Sargood
Keyword(s):  
Statistical Model ◽  
Excited States ◽  
Cross Sections ◽  
Reaction Rate ◽  
Ground States ◽  
Reaction Rates ◽  
Thermonuclear Reaction ◽  
Thermal Distribution ◽  
Naturally Occurring ◽  
Thermonuclear Reaction Rate

Values of the ratio of the thermonuclear reaction rate of a reaction, with target nuclei in a thermal distribution of energy states, to the reaction rate with all target nuclei in their ground states are tabulated for neutron, proton and (X-particle induced reactions on the naturally occurring nuclei from 2�Ne to 70Zn, at temperatures of 1, 2, 3�5 and 5 x 109 K. The ratios are determined from reaction rates based on statistical model cross sections.

scholarly journals Isomeric Cross Section Study of neutron induced reactions on Ge

2020 ◽  
Vol 16 ◽  
pp. 169
Author(s):  
R. Vlastou ◽  
S. Galanopoulos ◽  
C. T. Papadopoulos ◽  
M. Kokkoris ◽  
M. Serris ◽  
...  
Keyword(s):  
Statistical Model ◽  
Cross Section ◽  
Cross Sections ◽  
Reaction Cross ◽  
Model Calculations ◽  
Section Study ◽  
Reaction Cross Sections

The72Ge(n,α)69mZn, 74Ge(n,α)71mZn, 76Ge(n,2n)75g+mGe reaction cross sections have been measured from 9.6 to 11.4 MeV and studied, along with data from litera- ture, within the frame of statistical model calculations by using the code EMPIRE-II.

Cross Section Measurements for the Reactions 53Cr(p,g)54Mn, 53Cr(p,n)53Mn and 53Cr(p, p')53Cr

1981 ◽  
Vol 34 (1) ◽  
pp. 25 ◽  
Author(s):  
HJ Gardner ◽  
LW Mitchell ◽  
SR Kennett ◽  
MR Anderson ◽  
DG Sargood
Keyword(s):  
Statistical Model ◽  
Cross Section ◽  
Cross Sections ◽  
Proton Energy ◽  
Optical Model ◽  
Model Parameters ◽  
Model Calculations ◽  
Isobaric Analogue ◽  
Theory And Experiment

Cross sections have been measured for the reactions 53Cr(p, y)5 4Mn, 53Cr(p, n)53Mn and 53Cr(p, p/)53Cr over the proton energy range O'88-2'40 MeV. The results are compared with the predictions of statistical model, calculations with global optical model parameters, with particular reference to the role of isobaric analogue resonances. Satisfactory agreement between theory and experiment is achieved for all three reactions.

Cross sections and thermonuclear reaction rates for the 24Mg(α,n)27Si, 25Mg(p,n)25Al, 27Al(p,n)27Si, and 28Si(α,n)31S reactions

1980 ◽  
Vol 58 (5) ◽  
pp. 697-702 ◽  
Author(s):  
C. W. Cheng ◽  
J. D. King
Keyword(s):  
Statistical Model ◽  
Cross Sections ◽  
Theoretical Calculations ◽  
Reaction Rates ◽  
Model Calculations ◽  
Model Predictions ◽  
Low Energies ◽  
Positron Decay ◽  
Γ Rays ◽  
Good Agreement

Cross sections for the 24Mg(α,n)27Si, 25Mg(p,n)25Al, 27Al(p,n)27Si, and 28Si(α,n)31S reactions have been measured at energies from near threshold to 3 to 4 MeV above threshold by detection of 0.511 MeV γ-rays in coincidence following positron decay of the product nuclei. Comparison with the theoretical calculations of Woosley, Fowler, Holmes, and Zimmerman shows good agreement between experiment and theory except at low energies where the statistical model calculations tend to overestimate the cross section. Reaction rates have been calculated for temperatures of interest in explosive nucleosynthesis and found to be in good agreement with the statistical model predictions for temperatures above 2 × 109 K.

scholarly journals Cross Section Measurements of the 89Y(p,γ)90Zr eaction in the energy range Ep=1.6-2.4 MeV.

2019 ◽  
Vol 10 ◽  
pp. 154
Author(s):  
P. Tsagkari ◽  
E. Skreti ◽  
G. A. Souliotis ◽  
P. Demetriou ◽  
S. Harissopulos ◽  
...  
Keyword(s):  
Statistical Model ◽  
Total Cross Section ◽  
Energy Range ◽  
Nuclear Reaction ◽  
Cross Section ◽  
Proton Energy ◽  
Model Calculations

The total cross section of the nuclear reaction 89Y(p,7)90Zr has been measured over the proton energy range EP=1.6-2.4 MeV. The results are compared with the predictions of statistical model calculations

scholarly journals UV absorption cross sections of nitrous oxide (N<sub>2</sub>O) and carbon tetrachloride (CCl<sub>4</sub>) between 210 and 350 K and the atmospheric implications

2010 ◽  
Vol 10 (13) ◽  
pp. 6137-6149 ◽  
Author(s):  
N. Rontu Carlon ◽  
D. K. Papanastasiou ◽  
E. L. Fleming ◽  
C. H. Jackman ◽  
P. A. Newman ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Carbon Tetrachloride ◽  
Cross Section ◽  
Cross Sections ◽  
Atmospheric Model ◽  
Uv Absorption ◽  
Absorption Cross ◽  
Current Recommendation ◽  
Model Calculations ◽  
Good Agreement

Abstract. Absorption cross sections of nitrous oxide (N2O) and carbon tetrachloride (CCl4) are reported at five atomic UV lines (184.95, 202.548, 206.200, 213.857, and 228.8 nm) at temperatures in the range 210–350 K. In addition, UV absorption spectra of CCl4 are reported between 200–235 nm as a function of temperature (225–350 K). The results from this work are critically compared with results from earlier studies. For N2O, the present results are in good agreement with the current JPL recommendation enabling a reduction in the estimated uncertainty in the N2O atmospheric photolysis rate. For CCl4, the present cross section results are systematically greater than the current recommendation at the reduced temperatures most relevant to stratospheric photolysis. The new cross sections result in a 5–7% increase in the modeled CCl4 photolysis loss, and a slight decrease in the stratospheric lifetime, from 51 to 50 years, for present day conditions. The corresponding changes in modeled inorganic chlorine and ozone in the stratosphere are quite small. A CCl4 cross section parameterization for use in atmospheric model calculations is presented.

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