A systematic study of alpha decay in actinide nuclei using modified generalized liquid drop model

The alpha decay half-lives of actinides within modified generalized liquid drop model (MGLDM) are investigated by the Wentzel–Kramers–Brillouin (WKB) barrier penetration probability. The potential barrier was studied taking in to account of nuclear proximity, coulomb interaction and centrifugal potential with the inclusion of angular momentum. This work predicts the alpha decay half-lives of unknown actinide nuclei such as [Formula: see text]Am, [Formula: see text]Cm, [Formula: see text]Bk, [Formula: see text]Es and [Formula: see text]No. The calculated alpha decay half-lives reproduce accurately the experimental data. The predictions provided for the alpha decay half-lives within the MGLDM may be helpful for identifying the new isotopes in this field.

Theoretical studies on Alpha decay half-lives of Astatine isotopes

The half-life of a parent nucleus of Astatine isotopes [Formula: see text] decaying via alpha emission is investigated by employing Coulomb and proximity potential model (CPPM) using the WKB barrier penetration probability and other different analytical and semiempirical formulae of Royer, AKRE, Akrawy, RoyerB, MRoyerB, MRenB, SemFIS, VS and SLB. In the calculation of Alpha decay (AD) half-life the available experimental and theoretical [Formula: see text]-values with the total alpha kinetic energy have been considered. The behavior of hindrance factor with the variation of mass numbers of parent nuclei for isotopes in the range [Formula: see text] and the effect of magic number at closed shells were investigated. Through the comparison of obtained results from the systematics with the experimental data, the prediction of SemFIS formula was the best among the studied ones where it shows the minimum standard deviation of 0.829881.

THEORETICAL STUDY OF DECAY RATES OF NEWLY SYNTHESIZED SUPER HEAVY ELEMENT

We have studied half lives and penetration probability for even-even nuclei having atomic number 106 to 118.The frequency have been calculated using classical methods. The penetration probability was estimated by modifying the Gamow’s theory of alpha decay by varying the potential and it was found to be in a very good agreement with the experimental half-lives. The half-lives for alpha decay can be mainly determined by penetration probability. We have seen that in simple spherical symmetric potential there is a discontinuous jump of the potential which tends to be not physical because the force there becomes infinite. In this present work the square well model is modified by smoothing the potential well inside the nucleus to the top of the coulomb barrier at the outer side of the potential well which we will call as S-potential. The pre-formation factor was calculated from experimental alpha decay energies and half-lives. The theoretical explanation was experimentally proved by Geiger-Nuttall law. The S-potential (Smoothened) gives a better match with the experimental data.

Analysis of consequences of structural damage to the ISS Russian Segment caused by collision with space debris

Under the conditions of increasing littering in the near-Earth space, a quantitative estimate of the criticality of consequences of the ISS penetration with fragments of space debris is a necessary tool when developing measures to recover from the contingency related to the penetration. The ISS Russian Segment (RS) is mostly susceptible to penetration due to the fact that it includes transportation spacecraft, which have weaker shielding as compared with the station modules. In connection with this, there arises a problem of determining the degree of criticality for penetration of the pressure hull of the modules, transportation spacecraft, propellant tanks and bottles in the RS taking into account possible types of catastrophic consequences of the penetration and the distribution of the penetration risk over the modules and the transportation spacecraft. In order to solve the problem, a procedure was developed for calculating the risks of a catastrophic penetration of the station, based on breaking up the original problem into two stages. Calculated during the first stage is the probability of penetration of individual compartments constituting the station and having a certain type of shielding protection, using a finite-element geometrical model of the station and a model of the technogenic environment. The obtained results are used during the second stage of calculation of the catastrophic penetration probability using statistic test method (Monte-Carlo method). This method uses a model of the ISS RS consisting of compartments with simplified shapes (cylinders and truncated cones), which makes it possible to simplify the procedure for obtaining a random penetration location and reduce the time needed to obtain statistically valid results. Based on the procedure presented in the paper, a program was developed, which is used for calculating the probability of catastrophic consequences of the ISS RS penetration. Analysis of calculation results has shown that the relative probability of a catastrophic penetration accompanied by the loss of the crew and/or the station is 13.3%; probability of emergency crew evacuation because of the threat of hypoxia is 3.716%; probability of emergency crew evacuation in a spacecraft with a punctured orbital module is 21.59%. The paper proposes steps that need to be taken in order to further reduce the risk of catastrophic consequences of the penetration through including into onboard systems the subsystem for promptly determining coordinates of the penetration location, as well as the use of oxygen masks by the crew during recovery operations. Key words: International space station, ISS Russian Segment, meteoroid, space debris, protective shielding structure, penetration probability, probability of catastrophic consequences of penetration.

Correlation between alpha preformation probability, decay half-life and barrier assault frequency

Calculation of alpha particle preformation probabilities for some alpha emitters is considered in the framework of a recent proposed barrier penetration formula, by two different approximations. The behavior of alpha particle preformation probability with the variation of neutron and proton numbers of parent nuclei for isotopes, in the range [Formula: see text], and isotones, in the range [Formula: see text], is investigated. The same correlations are then studied for the alpha decay half-life, the barrier assault frequency, barrier height and barrier penetration probability. Strong correlations are found and in a good agreement with experimental expectations.

A systematic calculation of alpha decay half-lives using a new approach for barrier penetration probability

A systematic calculation of alpha decay half-lives of 347 nuclei is considered in the framework of the Wentzel–Kramers–Brillouin (WKB) approximation using two formulas. A recently proposed barrier penetration formula, with some modified parameters, is used first. Second, a new analytic barrier penetration formula is derived by taking into account the centrifugal potential. A good agreement with experimental data is achieved especially for spherical nuclei. The new formula reproduces experimental alpha decay half-lives with a satisfying accuracy especially for penetration energies much lower than the Coulomb barrier.

Penetration Efficiency Evaluation of Missile with Jammer

In order to improve the penetration efficiency of missile, an effective suggestion is fixing jammer in missile. The jamming can decrease the radar detection range of air-defense missile weapon system, so the intercept frequency is lessened. In this paper, it builds the intercept model of ship-to-air missile with radar detection range. Thus, the penetration probability of missile is presented. Finally, the simulation illustrates that the jamming is effective, and the results can provide suggestion on the jammer parameter design.