Recently, this crucial α-preformation probability was empirically deduced and exhibits a new feature that had been inferred to some extent by Professor REN Zhongzhou and his group from Department of Physics, Nanjing University. This work, titled "Model-independent trend of α-preformation probability", was published in SCIENCE CHINA Physics, Mechanics & Astronomy 2013, Vol. 56(8).
Pá values for the Po and Rn isotopic chains obtained from various models, including the present and previous results of the present group. A similar variation in all curves is clearly displayed.
Credit: ©Science China Press
Dating back to the end of the 19th century, nuclear physics established itself as a field of science with the discovery of radioactivity. Since those years, α decay has always been considered the eminent topic in nuclear physics. In particular, as the dominant decay mode of superheavy nuclei, it is currently the only useful tool in the identification of any new heavy element and its isotopes.
Theoretically, the decay process is usually imagined in the Gamow picture as a preformed α cluster tunneling through the α-daughter potential barrier. Without doubt, the α-preformation probability is critical in view of nuclear structure. Nevertheless, detailed studies of this quantity provide results that remain ambiguous, despite extensive experimental investigations.
In the present work, the authors proposed an empirical formula that for the first time directly deduces the preformation factor of the αparticle from the experimental data. The α-preformation factors of 171 even-even nuclei were initially obtained that strongly confirmed the key role played by the shell effect in the formation of the α cluster during decay. The study was also extended to include heavier cluster emissions with satisfactory results. These in turn prove to a certain degree that the present analysis of the α-preformation factor is reasonable and reliable.
Interestingly, a new feature of the α-preformation probability (Pα) became evident in a further study. From a different perspective, the α-preformation probabilities for a given isotopic chain extracted from different theoretical analyses were found to have quite similar behavior when comparing the present results with other studies. Across the various studies, the relative trend in the α-preformation probabilities for an isotopic chain were actually model-independent, although the deduced values of the α-preformation factor based on the respective model differ from each other (see Figure 1). The inference is that these studies are consistent with each other despite the different theoretical models, and the present study can be taken as a certain proof of reliability of the previous theoretical results.
This study gives valuable information on the preformation probability of emitted particles in α-decay, and the new model-independent feature has been identified in detail. The researchers hope that the present investigation can be extended to a broader range of nuclei, and be used to provide clues for their follow-up work on nuclear structure.
This research was supported by the National Natural Science Foundation of China (Grant Nos. 11035001, 10975072, 10735010 and 11120101005), the National Major State Basic Research and Development of China (Grant Nos. 2010CB327803 and 2013CB834400), the Knowledge Innovative Program of the Chinese Academy of Sciences (Grant No. KJCX2-SW-N02), the Research Fund of Doctoral Point (RFDP) (Grant No. 20100091110028), the Project Funded by the Priority Academic Programme Development of Jiangsu Higher Education Institutions (PAPD), the Research and Innovation Project for College Postgraduate of Jiangsu Province (Grant No. CXZZ12¬_0031) and the Science and Technology Development Fund of Macau (Grant No. 068/2011/A).
See the article: QIAN Y B, REN Z Z*. Model-independent trend of α-preformation probability. SCIENCE CHINA Physics, Mechanics & Astronomy, 2013, 56(8):1520-1524.
Science China Press Co., Ltd. (SCP) is a scientific journal publishing company of the Chinese Academy of Sciences (CAS). For 50 years, SCP takes its mission to present to the world the best achievements by Chinese scientists on various fields of natural sciences researches.
REN ZhongZhou | EurekAlert!
Breakthrough with a chain of gold atoms
17.02.2017 | Universität Konstanz
New functional principle to generate the „third harmonic“
16.02.2017 | Laser Zentrum Hannover e.V.
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
17.02.2017 | Medical Engineering
17.02.2017 | Medical Engineering
17.02.2017 | Health and Medicine