Dorin N. Poenaru | |
|---|---|
| Born | (1936-04-09)April 9, 1936 (age 89) |
| Citizenship | Romania |
| Alma mater | Politehnica University of Bucharest University of Bucharest |
| Known for | Cluster decay |
| Spouse | Dr. Ileana Hana Plonski |
| Scientific career | |
| Fields | Nuclear physics |
| Institutions | Horia Hulubei National Institute of Physics and Nuclear Engineering |
Dorin Mircea Stelian Poenaru (born April 9, 1936,Suiug,Bihor County) is aRomanian nuclear physicist and engineer. He contributed to the theory of heavy particle radioactivity (cluster decay).
Poenaru completed his higher education at theEmanuil Gojdu National College inOradea where in 1953 he received a diploma of merit. After passing theentrance examination, he studied at the Faculty of Electronics and Telecommunication ofPolitehnica University of Bucharest from which he graduated in 1958. In 1971, he received aB.A. in theoretical physics from theUniversity of Bucharest while working inelectronic engineering at the Institute of Atomic Physics (IFA) of theRomanian Academy inMăgurele, nearBucharest.[1]
He received hisPh.D. in nuclear electronics, from Politehnica University in 1968. He received a second Ph.D. intheoretical physics from the Central Institute of Physics, Bucharest in 1980.[1]
On June 30, 2017 he was elected honorary member of theRomanian Academy.[citation needed]
Poenaru organized the International Symposium "Advances in Nuclear Physics" celebrating the 50th anniversary of IFIN-HH, held in Bucharest in 1999 and theNATO Advanced Study Institute on "Nuclei far from Stability and Astrophysics",Predeal, 2000.
He was named one of the most valued reviewers of 2010 by the editors ofElsevier andNuclear Physics Other journals for which Poenarupeer reviewed articles includePhysical Review Letters,Physical Review C,Journal of Physics G: Nuclear and Particle Physics andCanadian Journal of Physics. He was a member of the Scientific Council of theJoint Institute for Nuclear Research,Dubna, 1996–1997.
He was projectmanager of the FP5European Union Centre of Excellence IDRANAP (InterDisciplinary Research and Applications based on Nuclear and Atomic Physics), selected in 2000 by theEuropean Commission among 34 successful proposals out of 185 applications from 11 countries.[2]
Poenaru designed and built about 15 electronic instruments, including a counting-rate meter with industrial applications, aclosed-circuit television system used at thecyclotron, a charge-sensitivelow-noise amplifier and a precisionpulse generator for asemiconductor detectorspectrometer and a switching circuit forphotomultiplier tubes.
He helped develop the theory of charge collection in semiconductor detectors and the formation of current or voltage pulses at the input of associated electronics. Poenaru producedexperimental works on nuclear reactions (e.g.,neutron evaporation spectra) and identification of new high-spinnuclear isomeric states. He experimented on fissionisomers (e.g.excitation functions, excitation energies, isomericyield, half-life measurements, angular correlations).[3]
He created ASAF and Numerical SuperAsymmetric Fission (NuSAF)models used to show thatalpha decay may be considered acold fissionprocess. He identified a new semi-empirical relationship (SemFIS) for half-life relative to alpha-decay based on fission theory, taking into account the shell effects.[4]
He published the most frequently-cited paper in the field ofcluster decay in 1980.[5] The next one was published in 1985.[6]
Starting in 1984, the following radioactivities were experimentally confirmed worldwide:14C,20O,23F,22,24-26Ne,28,30Mg, and32,34Si. The measured half-lives are in good agreement with theoretical predictions within the analytical superasymmetric fission (ASAF) model developed by Poenaru, W. Greiner, et al.
Citations of papers published by D. N. Poenaruet al. on heavy particle radioactivities started in 1984 after the first experimental confirmation by Rose and Jones of the14C radioactivity of 223Ra.
The phenomenon of heavy reactivity received wide popularity. The event was described by scientific journals, including La Recherche Nr. 159, Oct. 1984 p. 1300; Science et Vie Nr. 808, Jan. 1985 p. 42; Physics Bulletin Vol. 46 Nr. 489, 1985 p. 489,Scientific American Nr. 3, March 1990 p. 58 (translated into 9 languages), Europhysics News Nr. 5, Nr. 5, September/October 1996, p. 99 and by newspapers in Germany, Hungary, and Romania.
Many experimenters and theoreticians acknowledged D. N. Poenaru's contributions.[7][8][9][10][11][12]
Poenaru continued to investigate actively the field. He published in many journals and books, gave invited talks at International Conferences and led international seminars. He and his coworkers published comprehensive tables of half-lives for cluster emission used by experimentalists and other theorist as a guide or a reference. His ASAF model provides a unified approach ofcold fission,cluster decay andalpha decay.
The systematics of experimental results updated in 2002 was useful to stress that the strong shell effect of the daughter nucleus208Pb was not fully exploited, suggesting the need for new measurements.[13] In 2006, the barrier shape of some cluster decay modes were obtained by using the macroscopic-microscopic method. An alpha emitter (106Te) was discovered with a potential energy surface on which the alpha-decay valley may be seen by the same method.
An extensive study of alpha decay of superheavy nuclei was performed during the last decade, as a consequence of identifying new elements of the "island of stability".[14] A new method to estimate the preformation probability as a penetrability of the internal part of the barrier within a fission theory was developed.[15]
The simplest way to represent the systematics of half-lives for alpha-decay and heavy particle radioactivity is offered by the universal curve (UNIV), log T = f(log P) - a single straight line for a given even-even cluster decay mode, published in 1990. T is the half-life and P is the penetrability. The three fission models (ASAF, UNIV, and SemFIS) have been also applied to study the decay modes of superheavy nuclei produced in heavy ion fusion reactions atGSI Helmholtz Centre for Heavy Ion ResearchDarmstadt,Joint Institute for Nuclear ResearchDubna,RIKEN Japan, andLawrence Livermore National Laboratory, USA. For atomic numbersZ >122, it is possible that cluster decay may be stronger than (i.e. have a largerbranching ratio than) alpha decay.[16]
He extended thebinary fission theory to more complex phenomena such asternary fission (particle-accompanied fission) and multicluster fission was predicted. Quaternary fission (two-alpha accompanied fission) was experimentally discovered by Goennenwein et al. Pyatkov and Kamanin et al. in JINR Dubna are pursuing experiments on collinear ternary fission. In 2005, whenAlexandru Proca's death was commemorated, Poenaru used the opportunity to disseminate information about his relativistic equations of the massivevector bosonfield, as well as his life in Romania and in France.
Since 2007, the macroscopic-microscopic method was used to study the equilibrium shapes of metallicatomic clusters. Within these multidisciplinary investigations the hemispheroidal quantumharmonic oscillator, a new deformed single-particleshell model, was developed. The large yield of single ionizedtrimer (with twodelocalized electrons, the analogue of an alpha particle) observed in experiments on doubly ionized metallic clusters was explained. Unlike in fission of heavy nuclei, in this case both the liquid drop model deformation energy and the shell corrections versus the number of delocalized electrons of the light fragment reach a minimum at the well known magic number ne=2. It was suggested to use this type of fission mode innanotechnology.
Since 1964, Poenaru collaborated with scientists from JINR Dubna, CRN Strasbourg, Institut de physique nucleaire d'Orsay, CENBGBordeaux-Gradignan,Vanderbilt University (Nashville), Advanced Science Research Center ofJapan Atomic Energy Research Institute Tokai, Institut fuer Theoretische Physik der J. W. Goethe Universitaet,Frankfurt am Main,GSI Helmholtz Centre for Heavy Ion ResearchDarmstadt, andFrankfurt Institute for Advanced Studies.
During 53 years of scientific activity he spent nearly 11 years abroad: 2 months in Ukraine; 3 months in Russia; 3 months in Japan; 4 months in USA; one year and 10 months in France, and 8 years in Germany.
He published more than 189 articles in refereed journals (152ISI), 123 communications at international scientific meetings (54 invited talks, 30 oral contributions and 39 seminar talks). The first two conferences at which cluster decay modes were discussed were Varna in 1985 and Kyoto 1988.
He was coauthor or co-editor of 12 books; five in Romania and seven in USA, Germany, England, the Netherlands and Singapore.
He was mentioned with A. Săndulescu and W. Greiner in the NewEncyclopædia Britannica[17] for calculations, published in 1980, indicating the possibility of a new type of decay of nuclei: heavy particle radioactivity. In this way he became the 4th Romanian scientist mentioned inEncyclopædia Britannica, afterNicolae Paulescu,Henri Coandă, and Aureliu Săndulescu. In 1980 Sandulescu, Poenaru, and Greiner described calculations indicating the possibility of a new type of decay of heavy nuclei intermediate between alpha decay and spontaneous fission. The first observation of heavy-ion radioactivity was that of a 30-MeV, carbon-14 emission from radium-223 by H.J. Rose and G.A. Jones in 1984. (https://www.britannica.com/science/radioactivity#ref496381)
He was awarded theDeutsche Forschungsgemeinschaft (DFG) MERCATOR Gastprofessur position at theFrankfurt Institute for Advanced Studies,Goethe University Frankfurt in 2009. It is the highest award granted by the DFG each year.
In 2009 theEmanuil Gojdu National College inOradea, Romania, celebrated its 90th anniversary. The professional activity of some of the former students of this high school, including Prof. Poenaru, is presented in a small museum called the "Golden Book". The Laboratory of Physics bears his name.
A special issue of the Romanian Reports in Physics[18] (Vol. 59 (2007), nr.2) is devoted to Prof. Poenaru's 70th Anniversary, with worldwide contributions.[19][20]
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