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Sample records for bohrium

  1. From bohrium to copernicium and beyond SHE research at SHIP

    Science.gov (United States)

    Münzenberg, G.

    2015-12-01

    Heavy-element research with SHIP at GSI is reviewed including the discovery of the chemical elements bohrium to copernicium, experimental developments, cold fusion of heavy ions, and the discovery of a shell region around hassium. Elements bohrium and heavier are located beyond the limit of liquid-drop stability. They exist by shell stabilization. A universal, sensitive, and fast method: in-flight separation and identification of single atomic nuclei has been developed with the velocity filter SHIP and the detector system to measure decay sequences of individual atoms. Research with single atomic nuclei including detection methods, identification, and physics results will be discussed. Experiments with actinide targets as well as prospects with NUSTAR at FAIR will be addressed.

  2. Properties of an $\\alpha$ particle in a Bohrium $270$ Nucleus under the Generalized Symmetric Woods-Saxon Potential

    CERN Document Server

    Lütfüoğlu, B C

    2016-01-01

    The energy eigenvalues and the wave functions of an $\\alpha$ particle in a Bohrium $270$ nucleus were calculated by solving Schr\\"odinger equation for Generalized Symmetric Woods-Saxon potential. Using the energy spectrum by excluding and including the quasi-bound eigenvalues, entropy, internal energy, Helmholtz energy, and specific heat, as functions of reduced temperature were calculated. Stability and emission characteristics are interpreted in terms of the wave and thermodynamic functions. The kinetic energy of a decayed $\\alpha$ particle was calculated using the quasi-bound states, which is found close to the experimental value.

  3. Automatic Parallelization of Scientific Application

    DEFF Research Database (Denmark)

    Blum, Troels

    performance gains. Scientists working with computer simulations should be allowed to focus on their field of research and not spend excessive amounts of time learning exotic programming models and languages. We have with Bohrium achieved very promising results by starting out with a relatively simple approach...

  4. Systematic study of Bh isotopes in a relativistic mean field formalism

    International Nuclear Information System (INIS)

    The binding energy, charge radius, and quadrupole deformation parameter for the isotopic chain of the superheavy element bohrium (107Bh), from proton to neutron drip line, are calculated by using an axially deformed relativistic mean field model. The potential energy surfaces for some of the selected nuclei are plotted and the various possible shapes are investigated. The rms radii, density distributions, and two-neutron separation energies are also evaluated and the single-particle energies for some illustrative cases are analyzed to see the magic structures. Furthermore, the α-decay rates are calculated and compared with the available experimental data for the recently observed new isotopes 266,267Bh

  5. Paul Scherrer Institute Scientific Report 1999. Volume I: Particles and Matter

    International Nuclear Information System (INIS)

    Although originally planned for fundamental research in nuclear physics, the particle beams of pions, muons, protons and neutrons are now used in a large variety of disciplines in both natural science and medicine. The beams at PSI have the world's highest intensities and therefore allow certain experiments to be performed, which would not be possible elsewhere. The highlight of research this year was the first-ever determination of the chemical properties of the superheavy element 107 Bohrium. This was undertaken, by an international team led by H. Gaeggeler of PSI's Laboratory for Radiochemistry. Bohrium was produced by bombarding a Berkelium target with Neon ions from the Injector I cyclotron and six atoms were detected after having passed through an online gas chromatography device. At the Laboratory for Particle Physics the focus has shifted from nuclear physics to elementary particle physics with about a fifty-fifty split between investigations of rare processes or particle decays using the high intensity muon, pion and recently also polarized neutron beams of PSI, and research at the highest energy frontier at CERN (Geneva) and DESY (Hamburg). Important space instrumentation has been contributed by the Laboratory for Astrophysics to the European Space Agency and NASA satellite programmes. The Laboratory for Micro and Nanotechnology continued to focus on research into molecular nanotechnology and SiGeC nanostructures, the latter with the aim of producing silicon based optoelectronics. Progress in 1999 in these topical areas is described in this report. A list of scientific publications in 1999 is also provided

  6. A High Performance Backend for Array-Oriented Programming on Next-Generation Processing Units

    DEFF Research Database (Denmark)

    Lund, Simon Andreas Frimann

    are analyzed and experimentally tested. Resulting in the design and implementation of Bohrium a runtime-system for transforming, scheduling and executing array-oriented programs. Multiple interfaces for existing languages such as Python, C++, C#, and F# have been built which utilize the backend. A suite......The financial crisis, which started in 2008, spawned the HIPERFIT research center as a preventive measure against future financial crises. The goal of prevention is to be met by improving mathematical models for finance, the verifiable description of them in domain-specific languages...... of benchmarks applications, implemented in these languages, demonstrate the high-level declarative form of the programming model. Performance studies show that the high-level declarative programming model can be used to not only match but also exceed the performance of hand-coded implementations in low...

  7. Paul Scherrer Institute Scientific Report 1999. Volume I: Particles and Matter

    Energy Technology Data Exchange (ETDEWEB)

    Gobrecht, J.; Gaeggeler, H.; Herlach, D.; Junker, K.; Kettle, P.-R.; Kubik, P.; Zehnder, A. [eds.

    2000-07-01

    lthough originally planned for fundamental research in nuclear physics, the particle beams of pions, muons, protons and neutrons are now used in a large variety of disciplines in both natural science and medicine. The beams at PSI have the world's highest intensities and therefore allow certain experiments to be performed, which would not be possible elsewhere. The highlight of research this year was the first-ever determination of the chemical properties of the superheavy element {sup 107} Bohrium. This was undertaken, by an international team led by H. Gaeggeler of PSI's Laboratory for Radiochemistry. Bohrium was produced by bombarding a Berkelium target with Neon ions from the Injector I cyclotron and six atoms were detected after having passed through an online gas chromatography device. At the Laboratory for Particle Physics the focus has shifted from nuclear physics to elementary particle physics with about a fifty-fifty split between investigations of rare processes or particle decays using the high intensity muon, pion and recently also polarized neutron beams of PSI, and research at the highest energy frontier at CERN (Geneva) and DESY (Hamburg). Important space instrumentation has been contributed by the Laboratory for Astrophysics to the European Space Agency and NASA satellite programmes. The Laboratory for Micro and Nanotechnology continued to focus on research into molecular nanotechnology and SiGeC nanostructures, the latter with the aim of producing silicon based optoelectronics. Progress in 1999 in these topical areas is described in this report. A list of scientific publications in 1999 is also provided.

  8. Properties of Group Five and Group Seven transactinium elements

    Energy Technology Data Exchange (ETDEWEB)

    Wilk, Philip A.

    2001-05-01

    The detection and positive identification of the short-lived, low cross section isotopes used in the chemical studies of the heaviest elements are usually accomplished by measuring their alpha-decay, thus the nuclear properties of the heaviest elements must be examined simultaneously with their chemical properties. The isotopes 224 Pa and 266,267 Bh have been studied extensively as an integral part of the investigation of the heaviest members of the groups five and seven of the periodic table. The half-life of 224 Pa was determined to be 855 plus/minus19 ms by measuring its alpha-decay using our rotating wheel, solid state detector system at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. Protactinium was produced by bombardment of a bismuth target. New neutron rich isotopes, 267 Bh and 266 Bh, were produced in bombardments of a 249 Bk target and their decay was observed using the rotating wheel system. The 266 Bh that was produced decays with a half-life of approximately 1 s by emission of alpha particles with an average energy of 9.25 plus/minus 0.03 MeV. 267 Bh was observed to decay with a 17 s half-life by emission of alpha-particles with an average energy of 8.83 plus/minus 0.03 MeV. The chemical behavior of hafnium, Ha (element 105) was investigated using the fast on-line continuous liquid extraction and detection system SISAK-LISSY. Hafnium was not observed in this experiment following transport and extraction. Protactinium was used as on-line test of the apparatus to determine the experimental efficiency of the entire system. Unfortunately, the amount of protactinium observed after the extraction, compared to the amount produced, was extremely small, only 2.5%. The extraction of the protactinium isotope indicated the efficiency of the apparatus was too low to observe the extraction of hafnium. The chemical behavior of oxychloride compounds of bohrium was investigated by isothermal gas adsorption chromatography in a quartz column at 180, 150

  9. An experimental paradigm opening the world of superheavy elements

    Science.gov (United States)

    Armbruster, P.; Münzenberg, Gottfried

    2012-07-01

    The history of the discovery of the six elements Z = 107 ∓ 112, bohrium, hassium, meitnerium, darmstadtium, roentgenium, and copernicium goes back to the early 1960s. An experimental method to separate and identify rare nuclear reaction products, the recoil separation, was developed and optimised for beams of fission products at European research reactors. Chemical elements beyond the then first transactinides ( Z = 104), which owe their stability to the internal structure of atomic nuclei, were predicted theoretically. A big brother of the shell-stabilised nucleus 208Pb, a spherical magic nucleus at Z = 114∓126 and N = 184, might reach lifetimes long enough to be detected. In the seventies, hunting superheavy elements (SHE) was on the agenda of nuclear chemistry. Could the Periodic Table of Elements be extended to Z = 120, and is the order of electrons in the atom still following the laws established for lighter elements? In Germany, the heavy ion accelerator (UNILAC) was built by Christoph Schmelzer and his team at GSI, Darmstadt. SHE and UNILAC met the recoil separators in 1968, and SHIP (Separator for Heavy Ion reaction Products) was ready together with the first UNILAC-beams in 1976. Recoil separation is orders of magnitude more sensitive, selective, and faster than earlier methods used to synthesise elements up to seaborgium, Z = 106. The experimental paradigm we introduced opened the world of SHEs. At SHIP we discovered and investigated the elements Z = 107∓112 in the years 1980-2000. Our laboratory was the world champion during this time. Today our experimental method is used worldwide in the search for SHEs, but the leadership went to the Russian laboratory JINR in Dubna, which extended the Periodic Table by 6 more elements to Z = 118, the candidate for the next rare gas.

  10. Synthesis of the heaviest nuclei in cold fusion reactions

    Science.gov (United States)

    Münzenberg, G.; Morita, K.

    2015-12-01

    Cold fusion of heavy ions paved the way to superheavy elements. It was proposed by Yu.Ts. Oganessian more than forty years ago in 1974 [1,2]. First experiments were carried out at JINR Dubna, starting with the reaction 40Ar + 208Pb → 248Fm* where several hundreds to thousand atoms were produced on one day. The large production rate indicating an enhancement of the fusion cross section, especially for the evaporation of two or three neutrons, proved the concept of cold-fusion with the use of the doubly magic nucleus 208Pb as a target. The Dubna experiments were extended to the transactinide region beyond rutherfordium. The breakthrough came with the separation in-flight. Two different approaches were used: kinematic separation with the velocity filter SHIP [3] at GSI Darmstadt, and with the gasfilled separator GARIS [4,5] at RIKEN. With SHIP the concept of cold fusion of massive nuclear systems was convincingly confirmed by the observation of the one-neutron evaporation channel in the production of 247Rf in an irradiation of 208Pb with 50Ti [6] in 1981 which opened the way to the transactinide region. At SHIP the elements bohrium (107) to copernicium (112) were discovered [7]. A new closed shell region around hassium was found. The RIKEN experiments started in 2002. They confirmed the GSI results and in addition improved the data on structure and production of elements hassium to copernicium significantly. The heaviest element ever created in a cold fusion reaction, Z = 113, was observed at GARIS [8,9].

  11. Odd-Z Transactinide Compound Nucleus Reactions Including the Discovery of 260Bh

    International Nuclear Information System (INIS)

    Several reactions producing odd-Z transactinide compound nuclei were studied with the 88-Inch Cyclotron and the Berkeley Gas-Filled Separator at the Lawrence Berkeley National Laboratory. The goal was to produce the same compound nucleus at or near the same excitation energy with similar values of angular momentum via different nuclear reactions. In doing so, it can be determined if there is a preference in entrance channel, because under these experimental conditions the survival portion of Swiatecki, Siwek-Wilcznska, and Wilczynski's 'Fusion By Diffusion' model is nearly identical for the two reactions. Additionally, because the same compound nucleus is produced, the exit channel is the same. Four compound nuclei were examined in this study: 258Db, 262Bh, 266Mt, and 272Rg. These nuclei were produced by using very similar heavy-ion induced-fusion reactions which differ only by one proton in the projectile or target nucleus (e.g.: 50Ti + 209Bi vs. 51V + 208Pb). Peak 1n exit channel cross sections were determined for each reaction in each pair, and three of the four pairs; cross sections were identical within statistical uncertainties. This indicates there is not an obvious preference of entrance channel in these paired reactions. Charge equilibration immediately prior to fusion leading to a decreased fusion barrier is the likely cause of this phenomenon. In addition to this systematic study, the lightest isotope of element 107, bohrium, was discovered in the 209Bi(52Cr,n) reaction. 260Bh was found to decay by emission of a 10.16 MeV alpha particle with a half-life of 35 ms. The cross section is 59 pb at an excitation energy of 15.0 MeV. The effect of the N = 152 shell is also seen in this isotope's alpha particle energy, the first evidence of such an effect in Bh. All reactions studied are also compared to model predictions by Swiatecki, Siwek-Wilcznska, and Wilczynski's 'Fusion By Diffusion' theory

  12. Odd-Z Transactinide Compound Nucleus Reactions Including the Discovery of 260Bh

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Sarah L. [Univ. of California, Berkeley, CA (United States)

    2008-01-01

    Several reactions producing odd-Z transactinide compound nuclei were studiedwith the 88-Inch Cyclotron and the Berkeley Gas-Filled Separator at the Lawrence Berkeley National Laboratory. The goal was to produce the same compound nucleus ator near the same excitation energy with similar values of angular momentum via differentnuclear reactions. In doing so, it can be determined if there is a preference in entrancechannel, because under these experimental conditions the survival portion of Swiatecki, Siwek-Wilcznska, and Wilczynski's"Fusion By Diffusion" model is nearly identical forthe two reactions. Additionally, because the same compound nucleus is produced, theexit channel is the same. Four compound nuclei were examined in this study: 258Db, 262Bh, 266Mt, and 272Rg. These nuclei were produced by using very similar heavy-ion induced-fusion reactions which differ only by one proton in the projectile or target nucleus (e.g.: 50Ti + 209Bi vs. 51V + 208Pb). Peak 1n exit channel cross sections were determined for each reaction in each pair, and three of the four pairs' cross sections were identical within statistical uncertainties. This indicates there is not an obvious preference of entrancechannel in these paired reactions. Charge equilibration immediately prior to fusionleading to a decreased fusion barrier is the likely cause of this phenomenon. In addition to this systematic study, the lightest isotope of element 107, bohrium, was discovered in the 209Bi(52Cr,n) reaction. 260Bh was found to decay by emission of a 10.16 MeV alpha particle with a half-life of 35$+19\\atop{-9}$ ms. The cross section is 59 pb at an excitation energy of 15.0 MeV. The effect of the N = 152 shell is also seen in this isotope's alpha particle energy, the first evidence of such an effect in Bh. All reactions studied are also compared to model predictions by Swiatecki

  13. MicroSISAK. Continuous liquid-liquid extractions of radionuclides at {>=} 0.2 mL/min

    Energy Technology Data Exchange (ETDEWEB)

    Hild, D.; Eberhardt, K.; Kratz, J.V.; Wiehl, N. [Mainz Univ. (Germany). Inst. fuer Kernchemie; Even, J. [Mainz Univ. (Germany). Inst. fuer Kernchemie; Helmholtz-Institut Mainz, Mainz (Germany); Loeb, P.; Werner, B.; Hofmann, C. [Institut fuer Mikrotechnik Mainz GmbH, Mainz (Germany)

    2013-07-01

    extraction yield determined as the ratio of the Tc {gamma}-ray activities in both detectors was 76 {+-} 1%. With this experiment, it was demonstrated that MicroSISAK is in principle ready for an on-line experiment for the chemical characterization of the superheavy element bohrium, element 107. However, the detection of a-particle activities by liquid scintillation counting still needs to be worked out. (orig.)

  14. Developments for transactinide chemistry experiments behind the gas-filled separator TASCA

    International Nuclear Information System (INIS)

    synthesised carbonyl complexes were identified by nuclear decay spectroscopy. Some complexes were studied with isothermal chromatography or thermochromatography methods. The chromatograms were compared with Monte Carlo Simulations to determine the adsorption enthalpyrnon silicon dioxide and on gold. These simulations based on existing codes, that were modified for the different geometries of the chromatography channels. All observed adsorption enthalpies (on silcon oxide as well as on gold) are typical for physisorption. Additionally, the thermalstability of some of the carbonyl complexes was studied. This showed that at temperatures above 200 C therncomplexes start to decompose. It was demonstrated that carbonyl-complex chemistry is a suitable method to study rutherfordium, dubnium, seaborgium, bohrium, hassium, and meitnerium. Until now, only very simple, thermally stable compounds have been synthesized in the gas-phase chemistry of the transactindes. With the synthesis of transactinide-carbonyl complexes a new compound class would be discovered. Transactinide chemistry would reach the border between inorganic and metallorganic chemistry. Furthermore, the in-situ synthesised carbonyl complexes would allow nuclear spectroscopy studies under low background conditions making use of chemically prepared samples.