| 1. |
- Carlsson, Gillis, et al.
(författare)
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How to calculate α-decay rates in the future?
- 2016
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Ingår i: Nobel Symposium NS 160 - Chemistry and Physics of Heavy and Superheavy Elements. - : EDP Sciences. - 9782759890118 ; 131
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Konferensbidrag (refereegranskat)abstract
- New elements discovered during past decades have been created in fusion reactions where a lighter nucleus is collided with a heavier one. The new elements created often decay by emitting α particles. From the half-lives of the decays and the energies of the emitted particles one may extract some properties of the new elements. In this talk the recent work performed by the Lund group to model α decay starting from nuclear density-functional theory is reviewed and a possible extension is mentioned.
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| 2. |
- Forsberg, Ulrika, et al.
(författare)
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Congruence of decay chains of elements 113, 115, and 117
- 2016
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Ingår i: Nobel Symposium NS 160 – Chemistry and Physics of Heavy and Superheavy Elements : EPJ Web of Conferences - EPJ Web of Conferences. - : EDP Sciences. - 9782759890118 ; 131
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Konferensbidrag (refereegranskat)abstract
- Superheavy element research relies heavily on the detection of correlated decay chains. When several chains have been detected, it is natural to ask whether they form one congruent set, or whether they should be further divided into subsets. To statistically assess the congruence between the chains in a data set, we developed a procedure to calculate a Figure-of-Merit for low-number statistics. In this work, the method is applied to the world data set of odd-Z superheavy nuclei with Z ≥ 113. Some of the postulated sets of chains are found to be congruent, while others are not. The findings are of relevance for the IUPAC and IUPAP approvals of the new elements Z = 113, 115, and 117.
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| 3. |
- Jarlskog, Cecilia
(författare)
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Validation of new superheavy elements and IUPAC-IUPAP joint working group
- 2016
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Ingår i: Nobel Symposium NS 160 - Chemistry and Physics of Heavy and Superheavy Elements. - : EDP Sciences. - 9782759890118 ; 131
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Konferensbidrag (refereegranskat)abstract
- The great chemist Glenn Seaborg has written a delightful little book "Man-made Transuranium Elements", published in 1963, in which he points out that: "The former basic criterion for the discovery of a new element - namely, chemical identification and separation from all previously-known elements - had to be changed in the case of lawrencium (element 103). This also may be true for elements beyond lawrencium." Indeed this is what has happened. The elements with Z ≥ 103 are produced in nuclear reactions and are detected by counters. The detectors have undergone substantial refinement. For example one uses multiwire proportional chambers [for which George Charpak received the 1992 Nobel Prize in Physics] as well as solid state micro-strip detectors. In spite of this remarkable shift from chemistry to physics, the managerial staff of the International Union of Pure and Applied Chemistry (IUPAC) does not seem to be aware of what has been going on. The validation of superheavy elements should be done by physicists as the chemists lack the relevant competence as I will discuss here below. This article is about a collaboration between International Union of Pure and Applied Chemistry (IUPAC) and its sister organization International Union of Pure and Applied Physics (IUPAP), to deal with discovery of superheavy elements beyond Z = 112. I spent a great deal of time on this issue. In my opinion, the collaboration turned out to be a failure. For the sake of science, which should be our most important concern (and not politics), the rules for the future collaborations, if any, should be accurately defined and respected. The validation of new elements should be done by people who have the relevant competence - the physicists.
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| 4. |
- Khuyagbaatar, J., et al.
(författare)
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Fission in the landscape of heaviest elements: Some recent examples
- 2016
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Ingår i: Nobel Symposium NS 160 – Chemistry and Physics of Heavy and Superheavy Elements. - : EDP Sciences. - 9782759890118 ; 131
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Konferensbidrag (refereegranskat)abstract
- The fission process still remains a main factor that determines the stability of the atomic nucleus of heaviest elements. Fission half-lives vary over a wide range, 10^−19 to 10^24 s. Present experimental techniques for the synthesis of the superheavy elements that usually measure α-decay chains are sensitive only in a limited range of half-lives, often 10^5 to 10^3 s. In the past years, measurement techniques for very short-lived and very long-lived nuclei were significantly improved at the gas-filled recoil separator TASCA at GSI Darmstadt. Recently, several experimental studies of fission-related phenomena have successfully been performed. In this paper, results on 254−256Rf and 266Lr are presented and corresponding factors for retarding the fission process are discussed.
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| 5. |
- Lopez-Martens, A., et al.
(författare)
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Stability and synthesis of superheavy elements: Fighting the battle against fission - example of No-254
- 2016
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. - 9782759890118 ; 131
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Konferensbidrag (refereegranskat)abstract
- Superheavy nuclei exist solely due to quantum shell effects, which create a pocket in the potential-energy surface of the nucleus, thus providing a barrier against spontaneous fission. Determining the height of the fission barrier and its angular-momentum dependence is important to quantify the role that microscopic shell corrections play in enhancing and extending the limits of nuclear stability. In this talk, the first measurement of a fission barrier in the very heavy nucleus No-254 will be presented.
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| 6. |
- Rudolph, Dirk, et al.
(författare)
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Editorial
- 2016
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Ingår i: Nobel Symposium NS 160 – Chemistry and Physics of Heavy and Superheavy Elements : EPJ Web of Conferences - EPJ Web of Conferences. - : EDP Sciences. - 9782759890118 ; 131, s. 1-2
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Sarmiento, Luis G.
(författare)
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Nuclear spectroscopy with GEANT4 : The superheavy challenge
- 2016
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Ingår i: Nobel Symposium NS 160 - Chemistry and Physics of Heavy and Superheavy Elements. - : EDP Sciences. - 9782759890118 ; 131
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Konferensbidrag (refereegranskat)abstract
- The simulation toolkit Geant4 was originally developed at CERN for high-energy physics. Over the years it has been established as a swiss army knife not only in particle physics but it has seen an accelerated expansion towards nuclear physics and more recently to medical imaging and y- and ion-therapy to mention but a handful of new applications. The validity of Geant4 is vast and large across many particles, ions, materials, and physical processes with typically various different models to choose from. Unfortunately, atomic nuclei with atomic number Z > 100 are not properly supported. This is likely due to the rather novelty of the field, its comparably small user base, and scarce evaluated experimental data. To circumvent this situation different workarounds have been used over the years. In this work the simulation toolkit Geant4 will be introduced with its different components and the effort to bring the software to the heavy and superheavy region will be described.
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