scholarly journals Validation of nuclear reaction models for incident α-particles

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Hartmut Machner
Keyword(s):  
Nuclear Reaction ◽  
Compound Nucleus ◽  
Neutron Emission ◽  
Cascade Model ◽  
The Other ◽  
Reaction Products ◽  
Exciton Model ◽  
Intranuclear Cascade ◽  
Reaction Models ◽  
Α Particles

AbstractTwo different models allowing the calculation of reaction products are confronted with data from α-particle induced reactions. Both models contain a pre-equilibrium part and an equilibrium or compound nucleus part. The models are the exciton model in form of a code written by the author and TALYS. The other model is the intranuclear cascade model in form of the Liege-Saclay formulation incorporated in the PHITS code. The data are angle-integrated proton spectra from reactions with α-particle energies below 720 MeV and excitation functions from multi neutron emission with α-particle energies below 200 MeV.

A study of pre-equilibrium emission in α-induced reactions on 121,123Sb

1991 ◽  
Vol 69 (11) ◽  
pp. 1376-1382 ◽  
Author(s):  
B. P. Singh ◽  
H. D. Bhardwaj ◽  
R. Prasad
Keyword(s):  
Compound Nucleus ◽  
Mass Number ◽  
Neutron Emission ◽  
Theoretical Calculations ◽  
Exciton Model ◽  
Excitation Functions ◽  
Stacked Foil Technique ◽  
Equilibrium Emission ◽  
Charged Particle Emission ◽  
Foil Technique

Excitation functions for the 121Sb (α, n)+ 123Sb(α, 3n),,21Sb(α, 2n)+ 123Sb(α, 4n), 121Sb(α, 4n), 121Sb(α, 3np), and 123Sb(α, n) reactions are measured in the energy range 30–60 MeV using the stacked foil technique. In the cases of the 121Sb(α, n)+ 123Sb(α, 3n) and 121Sb(α, 2n)+ 123Sb(α, 4n) reaction pairs, the excitation functions for individual reactions were deduced using theoretical calculations. Excitation functions are also calculated theoretically using the compound-nucleus model with and without the inclusion of a pre-equilibrium emission. As expected, inclusion of a pre-equilibrium contribution based on the exciton model along with compound-nucleus calculations using the Hauser–Feshbach formalism reproduces well the measured excitation functions. Analysis of the data indicates a preference for a first chance neutron emission over charged-particle emission, and interesting trends in the energy and mass-number dependence of the pre-equilibrium fraction are observed.

FRAGMENTATION PRODUCTION CROSS-SECTIONS IN RELATIVISTIC COLLISIONS

2006 ◽  
Vol 21 (38) ◽  
pp. 2881-2892 ◽  
Author(s):  
İSKENDER DEMİRKOL
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Reaction Mechanisms ◽  
Production Cross ◽  
Cascade Model ◽  
Exciton Model ◽  
Intranuclear Cascade ◽  
The Cross ◽  
Semi Empirical ◽  
Equilibrium Effect

In this study, the fragmentation production cross-sections of heavy residual nuclides in the reactions 238 U (1 A GeV ) + p and p (1.2 GeV ) + 232 Th were calculated and the production of more than 370 different isotopes for this incident reactions was presented. The calculations were made by using the Cascade-Exciton Model including pre-equilibrium effect, the Intranuclear Cascade Model, the empirical and the semi-empirical parametrization. The results of the cross-sections obtained were compared with available experimental data and examined the relation between each other. It is seen that the precision of this models to estimate residue production cross-sections is still far from the performance required for technical applications and this incident model should be improved to obtain a deeper understanding of the reaction mechanisms involved in the production of isotopes.

scholarly journals Recent results on implosions directly driven at λ = 0·26-μm laser wavelength

1992 ◽  
Vol 10 (4) ◽  
pp. 573-583 ◽  
Author(s):  
M. Koenig ◽  
V. Malka ◽  
E. Fabre ◽  
P. Hammerling ◽  
A. Michard ◽  
...  
Keyword(s):  
Neutron Emission ◽  
Fusion Reaction ◽  
Laser Wavelength ◽  
Reconstruction Technique ◽  
Size Determination ◽  
Core Size ◽  
Reaction Products ◽  
X Ray ◽  
Emission Core ◽  
Α Particles

New diagnostics were implemented on the implosion experiments performed at LULI to improve our measurements of hydroefficiencies: Neutron chronometry gives the time of emission of the fusion reaction products as measured from the peak of the laser pulse; thereby making it possible to correlate the neutron emission with X-ray emission. Core imaging, based upon a maximum entropy reconstruction technique, leads to core size determination and also is a promising diagnostic for wall nonuniformities induced by irradiation conditions. A simple model is developed to retrieve experimental spectra of α-particles.

scholarly journals Recent Developments of the Liège Intranuclear Cascade Model in View of its Use into High-energy Transport Codes

2014 ◽  
Vol 118 ◽  
pp. 312-315 ◽  
Author(s):  
S. Leray ◽  
A. Boudard ◽  
B. Braunn ◽  
J. Cugnon ◽  
J.C. David ◽  
...  
Keyword(s):  
Energy Transport ◽  
High Energy ◽  
Cascade Model ◽  
Intranuclear Cascade ◽  
Recent Developments

On the Chemistry of Tetrabenzyl Thiuram Disulfide and Tetramethyl Thiuram Disulfide with Bis (Triethoxysilylpropyl) Tetrasulfide in Silica Compounds

2003 ◽  
Vol 76 (4) ◽  
pp. 876-891 ◽  
Author(s):  
R. N. Datta ◽  
A. G. Talma ◽  
S. Datta ◽  
P. G. J. Nieuwenhuis ◽  
W. J. Nijenhuis ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Succinic Anhydride ◽  
Dynamic Properties ◽  
The Other ◽  
Resonance Spectroscopy ◽  
Reaction Products ◽  
Negative Effect ◽  
Higher Temperature ◽  
Analytical Tools

Abstract The use of thiurams such as Tetramethyl thiuram disulfide (TMTD) or Tetrabenzyl thiuram disulfide (TBzTD) has been explored to achieve higher cure efficiency. The studies suggest that a clear difference exists between the effect of TMTD versus TBzTD. TMTD reacts with Bis (triethoxysilylpropyl) tetrasulfide (TESPT) and this reaction can take place even at room temperature. On the other hand, the reaction of TBzTD with TESPT is slow and takes place only at higher temperature. High Performance Liquid Chromatography (HPLC) with mass (MS) detection, Nuclear Magnetic Resonance Spectroscopy (NMR) and other analytical tools have been used to understand the differences between the reaction of TMTD and TESPT versus TBzTD and TESPT. The reaction products originating from these reactions are also identified. These studies indicate that unlike TMTD, TBzTD improves the cure efficiency allowing faster cure without significant effect on processing characteristics as well as dynamic properties. The loading of TESPT is reduced in a typical Green tire compound and the negative effect on viscosity is repaired by addition of anhydrides, such as succinic anhydride, maleic anhydride, etc.

scholarly journals Some nuclear transformations of beryllium and boron and the masses of the light elements

1935 ◽  
Vol 150 (869) ◽  
pp. 241-258 ◽  
Keyword(s):  
Spontaneous Emission ◽  
Periodic Table ◽  
Small Error ◽  
The Other ◽  
Light Elements ◽  
Mass Energy ◽  
Present Communication ◽  
Mass Data ◽  
The Masses ◽  
Α Particles

In a recent paper we showed that the nuclear transformations produced in lithium by bombarding the element with protons and with ions of heavy hydrogen were in complete accord with the laws of the conservation of mass-energy and of momentum. At the same time we pointed out that there were serious discrepancies between the mass-data and the transformation-data in some other cases, and we stressed the fact that the concordance for lithium was one between mass-differences, and gave no test of the correctness or otherwise of the absolute masses in terms of O 16 = 16·000. In the present communication we present the results of experiments on the transformation of beryllium and boron by protons and by ions of heavy hydrogen. It is shown that it is not possible to interpret these results on the mass-data at present available, and we indicate how the difficulties may be overcome by the assumption of a single small error in the mass-spectrographic value for the mass of He 4 . Beryllium So far as it is known beryllium consists of a single isotope,* the mass of which according to Bainbridge is 9·0155. This mass is greater than that of two α-partieles and a neutron (8·0043 + 1·0080§ = 9·0123) by nearly three million volts, and hence great difficulties have been en­countered in nuclear theory in accounting for the observed stability. It had been found by Rayleigh|| that the mineral beryl contained an abnormal quantity of helium, while the experiments of Curie-Joliot and of Chadwick¶ had shown that beryllium gave a copious emission of neutrons when bombarded by α-particles, but the most careful search has failed to give any evidence whatever for a spontaneous emission of particles from the element. Both lithium and boron, of atomic numbers 3 and 5 respectively, are very easily transformed by bombardment wit protons and with ions of heavy hydrogen, so that it was to be expected that beryllium, which lies between them in the periodic table, would also give effects when bombarded by the same ions. Observation of the energies evolved if the reactions are known with certainty, should then lead to values for the mass of Be 9 in terms of the masses of the other products of the transformations, which can be used to check the mass found by Bainbridge.

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