Photodisintegration of 127I: Systematic Uncertainties of Experiments and Data Evaluated Using Physical Criteria
Vladimir V. Varlamov,
Aleksandr I. Davydov,
Vadim N. Orlin
Issue:
Volume 8, Issue 5, September 2020
Pages:
64-72
Received:
24 August 2020
Accepted:
7 September 2020
Published:
23 September 2020
Abstract: The experimental data for photoneutron reaction cross sections for 127I obtained using beams of quasimonoenergetic annihilation photons and the method of neutron multiplicity-sorting at Livermore (USA) and Saclay (France) were analyzed using objective physical data reliability criteria. It was found that data of both laboratories contain significant systematic uncertainties and therefore are not reliable. New data for partial and total photoneutron reactions cross sections for 127I satisfied physical criteria of data reliability were evaluated using experimental-theoretical method based on both experimental neutron yield reaction cross-section and results of calculation in the combined photonucleon reaction model (CPNRM). The neutron yield reaction cross-section obtained at Saclay (France) was used in evaluation procedure. The newly evaluated cross sections for partial (γ, 1n), (γ, 2n) and (γ, 3n) reactions for 127I were used for discussion in detail the problems of significant disagreements between experimental data for many nuclei obtained at Saclay and Livermore. It was found that systematic uncertainties of experimental data for the (γ, 1n), (γ, 2n), and (γ, 3n) reactions cross sections for 127I obtained at both laboratories are of different nature. One of the reasons of noticeable systematic uncertainties of cross sections obtained are the shortcomings of the procedures used to separate counts into 1n, 2n, and 3n events. At the same time it was shown that the main reason of significant disagreements between new evaluated data and data obtained at Livermore experiment for 127I is the loss of many neutrons from the (γ, 1n) reaction. This situation is analogous to those in Livermore experiments for 75As and 181Ta.
Abstract: The experimental data for photoneutron reaction cross sections for 127I obtained using beams of quasimonoenergetic annihilation photons and the method of neutron multiplicity-sorting at Livermore (USA) and Saclay (France) were analyzed using objective physical data reliability criteria. It was found that data of both laboratories contain significan...
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Dependence of Detonation Velocity of Explosives on Effective Atomic Number and Effective Electron Density of the Explosives
Tohe Tessema Teklemariam,
Vijay Kumar Mittal
Issue:
Volume 8, Issue 5, September 2020
Pages:
73-77
Received:
21 September 2020
Accepted:
6 November 2020
Published:
19 November 2020
Abstract: Detonation velocity is one of the most important characteristics of explosives. For solid hydro carbon-based explosives it is generally greater than 4000 m/s. Detonation velocity depends to some extent upon the particle size of the explosives, increased charge diameter and increased confinement of the explosive. There is no report indicating the dependence of detonation velocity on the effective atomic number and effective electron density of the explosive. In the present work, we have arbitrarily chosen eight explosives. Four of these have detonation velocity between 9400 and 10100 m/s, and the other four has detonation velocity between 4500 and 5300 m/s. Direct method was used to calculate effective atomic number and effective electron densities various explosives. On calculating effective atomic number and effective electron density, it was found that detonation velocity of explosives does depend upon these two parameters. For explosives with high detonation velocity, effective atomic number is high and effective electron density is low while for low detonation velocity explosives it is reverse. It was also found that the variation of effective atomic number and effective electron density as a function of gamma ray energy can be explained on the basis of three different gamma ray inter action mechanism of gamma rays with matter.
Abstract: Detonation velocity is one of the most important characteristics of explosives. For solid hydro carbon-based explosives it is generally greater than 4000 m/s. Detonation velocity depends to some extent upon the particle size of the explosives, increased charge diameter and increased confinement of the explosive. There is no report indicating the de...
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