SwePub - sökning: WFRF:(Kindler B.)

Numrering	Referens	Omslagsbild	Hitta
1.	Kanungo, R., et al. (författare) Exploring the anomaly in the interaction cross section and matter radius of 23O 2011 Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993 .- 0556-2813 .- 1089-490X. ; 84:6, s. art. no. 061304(R)- Tidskriftsartikel (refereegranskat)abstract New measurements of the interaction cross sections of 22,23O at 900A MeV performed at the GSI, Darmstadt are reported that address the unsolved puzzle of the large cross section previously observed for 23O. The matter radii for these oxygen isotopes extracted through a Glauber model analysis are in good agreement with the new predictions of the ab initio coupled-cluster theory reported here. They are consistent with a 22O+neutron description of 23O as well.
2.	Kanungo, R., et al. (författare) Matter radii of 32-35Mg 2011 Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993 .- 0556-2813 .- 1089-490X. ; 83:2 Tidskriftsartikel (refereegranskat)abstract The interaction cross sections of Mg32-35 at 900A MeV have been measurmed using the fragment separator at GSI. The deviation from the r(0)A(1/3) trend is slightly larger for Mg-35, signaling the possible formation of a longer tail in the neutron distribution for Mg-35. The radii extracted from a Glauber model analysis with Fermi densities are consistent with models predicting the development of neutron skins.
3.	Kanungo, R., et al. (författare) One-Neutron Removal Measurement Reveals O-24 as a New Doubly Magic Nucleus 2009 Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 102:15 Tidskriftsartikel (refereegranskat)abstract The first measurement of the momentum distribution for one-neutron removal from O-24 at 920A MeV performed at GSI, Darmstadt is reported. The observed distribution has a width (FWHM) of 99 +/- 4 MeV/c in the projectile rest frame and a one-neutron removal cross section of 63 +/- 7 mb. The results are well explained with a nearly pure 2s(1/2) neutron spectroscopic factor of 1.74 +/- 0.19 within the eikonal model. This large s-wave probability shows a spherical shell closure thereby confirming earlier suggestions that O-24 is a new doubly magic nucleus.
4.	Nociforo, C., et al. (författare) One-neutron removal reactions on Al isotopes around the N=20 shell closure 2012 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X .- 2469-9985 .- 2469-9993. ; 85:4, s. 044312-1-044312-10 Tidskriftsartikel (refereegranskat)abstract The one-neutron removal cross sections of neutron-rich Al isotopes and longitudinal momentum distributions of the residues have been measured for A=33 to 36 at relativistic energies (≈900 MeV/u). The inclusive data have been interpreted within the eikonal approximation. The evolution of the single-particle occupancy in the ground state of 33,34,35Al has been studied and compared with shell model predictions. The inferred 2s1/2 neutron occupancy in the 33Al ground-state wave function is 20% to 40% lower than the predicted one. The inclusive data do not exclude the presence of intruder states. Some intruder l=1 occupancy is found in 34Al, similarly to 33Mg. The single-particle 1f7/2 occupancy shows a gradual increase at N=22. Correspondingly, a decrease of the 1d3/2 strength has been observed.
5.	Nociforo, C., et al. (författare) Shell Closure N=16 in O-24 2009 Ingår i: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 1165, s. 90-93 461 Konferensbidrag (refereegranskat)abstract Advanced nuclear structure models predict the presence of the shell closures N=14, 16 in neutron-rich O isotopes rather than N=20. Spectroscopic investigations performed at the neutron drip line have recently confirmed such predictions showing that the O-24 is a doubly magic nucleus (Z=8, N=16). Predictions within the shell model calculation for the O-23,O-24 ground state have been confirmed measuring their spectroscopic factors. Results obtained in one-neutron removal reactions performed by using in-flight radioactive ion beams produced at the Fragment Separator FRS of GSI are reported.
6.	Andreyev, A. N., et al. (författare) alpha-decay of the new isotope Po-187 : Probing prolate structures beyond the neutron mid-shell at N=104 2006 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 73:4, s. 044324- Tidskriftsartikel (refereegranskat)abstract The new neutron-deficient isotope Po-187 has been identified in the complete fusion reaction Ti-46+Sm-144 -> Po-187+3n at the velocity filter SHIP. Striking features of the Po-187 alpha decay are the strongly-hindered decay to the spherical ground state and unhindered decay to a surprisingly low-lying deformed excited state at 286 keV in the daughter nucleus Pb-183. Based on the potential energy surface calculations, the Po-187 ground state and the 286 keV excited state in Pb-183 were interpreted as being of prolate origin. The systematic deviation of the alpha-decay properties in the lightest odd-A Po isotopes relative to the smooth behavior in the even-A neighbors is discussed. Improved data for the decay of Bi-187(m,g) were also obtained.
7.	Andreyev, A. N., et al. (författare) alpha decay of the new isotopes Rn-193,Rn-194 2006 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 74:6, s. 064303- Tidskriftsartikel (refereegranskat)abstract The new neutron-deficient isotopes Rn-193,Rn-194 have been identified in the complete fusion reaction Cr-52+Sm-144 -> Rn-196(*) at the velocity filter SHIP. The alpha-decay energy and half-life value of Rn-194 were determined to be E-alpha=7700(10) keV and T-1/2=0.78(16) ms, respectively. For Rn-193 the half-life of T-1/2=1.15(27) ms and two alpha lines at E-alpha 1=7685(15) keV, I-alpha 1=74(20)% and E-alpha 2=7875(20) keV, I-alpha 2=26(12)% were found. The decay pattern of Rn-193, which is substantially different from that of the heavier odd-A Rn isotopes, provides first experimental evidence for the long-predicted deformation in the very neutron-deficient Rn nuclei.
8.	Andreyev, A. N., et al. (författare) Signatures of the Z=82 shell closure in alpha-decay process 2013 Ingår i: Physical Review Letters. - : American Physical Society (APS). - 0031-9007 .- 1079-7114. ; 110:24 Tidskriftsartikel (refereegranskat)abstract In recent experiments at the velocity filter Separator for Heavy Ion reaction Products (SHIP) (GSI, Darmstadt), an extended and improved set of α-decay data for more than 20 of the most neutron-deficient isotopes in the region from lead to thorium was obtained. The combined analysis of this newly available α-decay data, of which the Po186 decay is reported here, allowed us for the first time to clearly show that crossing the Z=82 shell to higher proton numbers strongly accelerates the α decay. From the experimental data, the α-particle formation probabilities are deduced following the Universal Decay Law approach. The formation probabilities are discussed in the framework of the pairing force acting among the protons and the neutrons forming the α particle. A striking resemblance between the phenomenological pairing gap deduced from experimental binding energies and the formation probabilities is noted. These findings support the conjecture that both the N=126 and Z=82 shell closures strongly influence the α-formation probability.
9.	Antalic, S., et al. (författare) The new isotopes in Po-Rn region 2007 Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 38:4, s. 1557-1560 Tidskriftsartikel (refereegranskat)abstract This contribution reviews the results of the recent experiments at the velocity filter SHIP in GSI Darmstadt obtained in the region of neutron deficient isotopes from lead to radon. The data for new very neutron-deficient isotopes Po-187, Rn-193,Rn-194 and their decay properties are presented. The isotopes were produced and identified in the complete fusion reactions Ti-46+Sm-144 -> Po-187+3n and Cr-52+Sm-144 -> Rn-194,Rn-193+2,3n.
10.	Cox, D. M., et al. (författare) Spectroscopy along flerovium decay chains. II. Fine structure in odd-A 289Fl 2023 Ingår i: Physical Review C. - 2469-9985. ; 107:2 Tidskriftsartikel (refereegranskat)abstract Fifteen correlated α-decay chains starting from the odd-A superheavy nucleus 289Fl were observed following the fusion-evaporation reaction 48Ca+244Pu. The results call for at least two parallel α-decay sequences starting from at least two different states of 289Fl. This implies that close-lying levels in nuclei along these chains have quite different spin-parity assignments. Further, observed α-electron and α-photon coincidences, as well as the α-decay fine structure along the decay chains, suggest a change in the ground-state spin assignment between 285Cn and 281Ds. Our experimental results, on the excited level structure of the heaviest odd-N nuclei to date, provide a direct testing ground for theory. This is illustrated by comparison with new nuclear structure calculations based on the symmetry-conserving configuration mixing theory.
11.	Kanungo, R., et al. (författare) Structure of Mg-33 sheds new light on the N=20 island of inversion 2010 Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - Elsevier : Elsevier BV. - 0370-2693 .- 1873-2445. ; 685:4-5, s. 253-257 Tidskriftsartikel (refereegranskat)abstract The first reaction spectroscopy oil the ground state structure of Mg-33 through the measurement of the longitudinal momentum distribution from the one-neutron removal reaction Using a C target at 898A MeV is reported The experiment was performed at the FRS, GSI The distribution has a relatively narrow width (150 +/- 3 MeV/c (FWHM)) and the one-neutron removal cross-section is 74 +/- 4 mb An increased contribution from the (2)p(3/2) orbital is required to explain the observation showing its lowering compared to existing model predictions This provides new information regarding the configuration of Mg-33 and the island of inversion (C) 2010 Elsevier B V All rights reserved
12.	Khuyagbaatar, J., et al. (författare) Search for elements 119 and 120 2020 Ingår i: Physical Review C. - 2469-9985. ; 102:6 Tidskriftsartikel (refereegranskat)abstract A search for production of the superheavy elements with atomic numbers 119 and 120 was performed in the 50Ti+249Bk and 50Ti+249Cf fusion-evaporation reactions, respectively, at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. Over four months of irradiation, the 249Bk target partially decayed into 249Cf, which allowed for a simultaneous search for both elements. Neither was detected at cross-section sensitivity levels of 65 and 200 fb for the 50Ti+249Bk and 50Ti+249Cf reactions, respectively, at a midtarget beam energy of Elab = 281.5 MeV. The nonobservation of elements 119 and 120 is discussed within the concept of fusion-evaporation reactions including various theoretical predictions on the fission-barrier heights of superheavy nuclei in the region of the island of stability.
13.	Saito, T. R., et al. (författare) The WASA-FRS project at GSI and its perspective 2023 Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - : Elsevier. - 0168-583X .- 1872-9584. ; 542, s. 22-25 Tidskriftsartikel (refereegranskat)abstract A novel technique to study bound states of exotic hadrons in subatomic nuclei, such as hypernuclei and mesic nuclei, has been developed by employing the Fragment Separator FRS and the WASA central detector at GSI. Two experiments, S447 for studying light hypernuclei, especially hypertriton and a Ann bound state, and S490 for searching for ri' mesic-nuclei, were recently performed. Data analyses are currently in progress, and light charged particles such as protons and x & PLUSMN; are clearly observed and identified in the both experiments. For S447, light nuclear fragments that can also be residual nuclei from decays of hypernuclei of interests have been analysed by the FRS, and a momentum resolution, Ap/p, of 5 x 10-4 has been achieved. Further data analyses are to be completed. The WASA-FRS project will be continued and extended with the FRS at FAIR Phase 0, and upgrading of the WASA magnet and detectors is currently in progress. Furthermore, construction of a larger detector system with the Super-FRS at FAIR Phase 1 is also under consideration.
14.	Såmark-Roth, A., et al. (författare) Low-lying states in 219Ra and 215Rn : Sampling microsecond α-decaying nuclei 2018 Ingår i: Physical Review C. - 2469-9985. ; 98:4 Tidskriftsartikel (refereegranskat)abstract Short-lived α-decaying nuclei "northeast" of 208Pb in the chart of nuclides were studied using the reaction 48Ca+243Am with the decay station TASISpec at TASCA, GSI Darmstadt. Decay energies and times from pile-up events were extracted with a tailor-made pulse-shape analysis routine and specific α-decay chains were identified in a correlation analysis. Decay chains starting with the even-even 220Ra and its odd-A neighbors, 219Fr, and 219,221Ra, with a focus on the 219Ra→215Rn decay, were studied by means of α-γ spectroscopy. A revised α-decay scheme of 219Ra is proposed, including a new decay branch from a previously not considered isomeric state at 17 keV excitation energy. Conclusions on nuclear structure are drawn from the experimental data, aided by Geant4 simulations and a discussion on theoretical calculations.
15.	Såmark-Roth, A., et al. (författare) Spectroscopy along flerovium decay chains. III. Details on experiment, analysis, 282Cn, and spontaneous fission branches 2023 Ingår i: Physical Review C. - 2469-9985. ; 107:2 Tidskriftsartikel (refereegranskat)abstract Flerovium isotopes (element Z = 114) were produced in the fusion-evaporation reactions 48Ca+242,244Pu and studied with an upgraded TASISpec decay station placed in the focal plane of the gas-filled separator TASCA at the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Germany. Twenty-nine flerovium decay chains were identified by means of correlated implantation, α decay, and spontaneous fission events. Data analysis aspects and statistical assessments, primarily based on measured rates of various events, which laid the foundation for the comprehensive spectroscopic information on the flerovium decay chains, are presented in detail. Various decay scenarios of an excited state observed in 282Cn are examined in depth with the help of GEANT4 simulations and assessed by predictions of beyond mean-field calculations including triaxial shape degrees of freedom. Previous, revised, and newly derived fission probabilities of even-even superheavy nuclei are compared with various theoretical predictions.
16.	Tanaka, Y. K., et al. (författare) Search for eta '-mesic nuclei using (p,d) reaction with FRS/Super-FRS at GSI/FAIR 2020 Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 1643 Tidskriftsartikel (refereegranskat)abstract We plan a semi-exclusive measurement of the C-12(p,dp) reaction to search for eta'-mesic nuclei, aiming at investigating in-medium properties of the eta'-meson. We employ a 2.5 GeV proton beam impinging on a carbon target to produce eta'-mesic C-11 nuclei via the C-12(p,d)eta'circle times C-11 reaction. Using coincidence measurements of the forward going deuterons, important for missing-mass spectroscopy, and decay protons emitted from the eta'-mesic nuclei for event selection will provide a high experimental sensitivity to observe eta'-mesic nuclei. We will perform the measurements by combining the WASA detector system with the fragment separator FRS at GSI and also with the Super-FRS at FAIR in the future. The plan of the experiments and the present status are reported.
17.	Tanaka, Y. K., et al. (författare) WASA-FRS EXPERIMENTS IN FAIR PHASE-0 AT GSI 2023 Ingår i: ACTA PHYSICA POLONICA B PROCEEDINGS SUPPLEMENT. - : Jagiellonian University. Konferensbidrag (refereegranskat)abstract We have developed a new and unique experimental setup integrating the central part of the Wide Angle Shower Apparatus (WASA) into the Fragment Separator (FRS) at GSI. This combination opens up possibilities of new experiments with high-resolution spectroscopy at forward 0 and measurements of light decay particles with nearly full solid-angle acceptance in coincidence. The first series of the WASA-FRS experiments have been successfully carried out in 2022. The developed experimental setup and two physics experiments performed in 2022 including the status of the preliminary data analysis are introduced.
18.	Andersson, L-L, et al. (författare) TASISpec - A Highly Efficient Multi-coincidence Spectrometer for Nuclear Structure Investigations of the Heaviest Nuclei 2010 Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 622:1, s. 164-170 Tidskriftsartikel (refereegranskat)abstract TASISpec (TASCA in Small Image mode Spectroscopy) combines composite Ge- and Si-detectors for a new detector setup aimed towards multi-coincidence gamma -ray, X-ray, conversion electron, fission fragment, and a-particle spectroscopy of the heaviest nuclei. It exploits the TASCA separator's unique small image focal mode, i.e. the fact that evaporation residues produced in fusion-evaporation reactions can be focused into an area of less than 3 cm in diameter. This provides the possibility to pack detectors in very close geometry, resulting in an unprecedented detection efficiency of radioactive decays in prompt and delayed coincidence with implanted nuclei. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.
19.	Andreyev, A. N., et al. (författare) Shape-changing particle decays of Bi-185 and structure of the lightest odd-mass Bi isotopes 2004 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 69:5, s. 054308- Tidskriftsartikel (refereegranskat)abstract Proton and alpha decay of the proton-rich nuclide Bi-185 has been restudied in more detail in the complete fusion reaction Nb-93(Mo-95, 3n)Bi-185 at the velocity filter SHIP. The observed decay pattern of Bi-185 and of the heavier odd-mass isotopes Bi-187,Bi-189,Bi-191,Bi-193 are interpreted based on potential-energy surface calculations. It is shown that the experimental systematics of the particle decays and of the excited states in these nuclei (where known) can be explained by the prolate-oblate shape co-existence at low excitation energy. The observed state in Bi-185 is proposed to be of prolate nature, which is in contrast with the previously proposed oblate interpretation.
20.	Cox, D. M., et al. (författare) Spectroscopic Tools Applied to Flerovium Decay Chains 2020 Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 1643 Tidskriftsartikel (refereegranskat)abstract An upgraded TASISpec setup, with the addition of a veto DSSD and the new Compex detector-germanium array, has been employed with the gas-filled recoil separator TASCA at the GSI Helmholtzzentrum für Schwerionenforschung Darmstadt, to study flerovium (element 114) decay chains. The detector upgrades along with development of new analytical techniques have improved the sensitivity of the TASISpec setup for measuring α-photon coincidences. These improvements have been assessed with test reactions. The reaction 48Ca+206,207Pb was used for verification of experimental parameters such as transmission to implantation DSSD and target-segment to α-decay correlations. The reaction 48Ca+ natHf was used to produce several short-lived nuclei with multiple-α decay chains to investigate pile-up event deconvolution.
21.	Di Nitto, A., et al. (författare) ALBEGA: A Decay Spectroscopy Setup for Chemically Separated Samples 2015 Ingår i: GSI Report. ; 2015-1, s. 184-184 Bokkapitel (refereegranskat)
22.	Di Nitto, A., et al. (författare) Identification of Reaction Products in 50Ti+249Cf Reactions at TASCA 2017 Ingår i: GSI Scientific Report 2016. - 0174-0814. ; 2017-1, s. 203-203 Bokkapitel (refereegranskat)
23.	Di Nitto, A., et al. (författare) Study of Non-fusion Products in the 50Ti+249Cf Reaction 2018 Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 784, s. 199-205 Tidskriftsartikel (refereegranskat)abstract The isotopic distribution of nuclei produced in the 50Ti + 249Cf reaction has been studied at the gas-filled recoil separator TASCA at GSI Darmstadt, which separates ions according to differences in magnetic rigidity. The bombardment was performed at an energy around the Bass barrier and with the TASCA magnetic fields set for collecting fusion-evaporation reaction products. Fifty-three isotopes located “north-east” of 208Pb were identified as recoiling products formed in non-fusion channels of the reaction. These recoils were implanted with energies in two distinct ranges; besides one with higher energy, a significant low-energy contribution was identified. The latter observation was not expected to occur according to kinematics of the known types of reactions, namely quasi-elastic, multi-nucleon transfer, deep-inelastic collisions or quasifission. The present observations are discussed within the framework of two-body kinematics passing through the formation of a composite system.
24.	Düllmann, Ch. E., et al. (författare) Production and Decay of Element 114: High Cross Sections and the New Nucleus 277Hs 2010 Ingår i: Physical Review Letters. - 1079-7114. ; 104:25 Tidskriftsartikel (refereegranskat)abstract The fusion-evaporation reaction 244Pu(48Ca, 3-4n)288,289114 was studied at the new gas-filled recoil separator TASCA. Thirteen correlated decay chains were observed and assigned to the production and decay of 288,289114. At a compound nucleus excitation energy of E* = 39.8-43.9 MeV, the 4n evaporation channel cross section was 9.8(-3.1)(+3.9) pb. At E* = 36.1-39.5 MeV, that of the 3n evaporation channel was 8.0-(+7.4)(4.5) pb. In one of the 3n evaporation channel decay chains, a previously unobserved alpha branch in 281Ds was observed ( probability to be of random origin from background: 0.1%). This alpha decay populated the new nucleus 277Hs, which decayed by spontaneous fission after a lifetime of 4.5 ms.
25.	Forsberg, U., et al. (författare) Recoil-α-fission and recoil-α-α-fission events observed in the reaction 48Ca + 243Am 2016 Ingår i: Nuclear Physics, Section A. - : Elsevier BV. - 0375-9474. ; 953, s. 117-138 Tidskriftsartikel (refereegranskat)abstract Products of the fusion-evaporation reaction 48Ca + 243Am were studied with the TASISpec set-up at the gas-filled separator TASCA at the GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany. Amongst the detected thirty correlated α-decay chains associated with the production of element Z=115, two recoil-α-fission and five recoil-α-α-fission events were observed. The latter five chains are similar to four such events reported from experiments performed at the Dubna gas-filled separator, and three such events reported from an experiment at the Berkeley gas-filled separator. The four chains observed at the Dubna gas-filled separator were assigned to start from the 2n-evaporation channel 289115 due to the fact that these recoil-α-α-fission events were observed only at low excitation energies. Contrary to this interpretation, we suggest that some of these recoil-α-α-fission decay chains, as well as some of the recoil-α-α-fission and recoil-α-fission decay chains reported from Berkeley and in this article, start from the 3n-evaporation channel 288115.
26.	Forsberg, Ulrika, et al. (författare) Spectroscopic Tools Applied to Element Z = 115 Decay Chains 2014 Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2100-014X .- 2101-6275. - 9782759811755 - 9782759811762 ; 66, s. 02036-02036 Konferensbidrag (refereegranskat)abstract Nuclides that are considered to be isotopes of element Z = 115 were produced in the reaction 48Ca + 243Am at the GSI Helmholtzzentrum für Schwerionenforschung Darmstadt. The detector setup TASISpec was used. It was mounted behind the gas-filled separator TASCA. Thirty correlated α-decay chains were found, and the energies of the particles were determined with high precision. Two important spectroscopic aspects of the offline data analysis are discussed in detail: the handling of digitized preamplified signals from the silicon strip detectors, and the energy reconstruction of particles escaping to upstream detectors relying on pixel-by-pixel dead-layer thicknesses.
27.	Gates, J. M., et al. (författare) First Superheavy Element Experiments at the GSI Recoil Separator TASCA: The Production and Decay of Element 114 in the 244Pu(48Ca,3-4n) Reaction 2011 Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 83:5 Tidskriftsartikel (refereegranskat)abstract Experiments with the new recoil separator, Transactinide Separator and Chemistry Apparatus (TASCA), at the GSI were performed by using beams of Ca-48 to irradiate targets of Pb206-208, which led to the production of No252-254 isotopes. These studies allowed for evaluation of the performance of TASCA when coupled to a new detector and electronics system. By following these studies, the isotopes of element 114 ((288-291)114) were produced in irradiations of Pu-244 targets with Ca-48 beams at compound nucleus excitation energies around 41.7 and 37.5 MeV, demonstrating TASCA's ability to perform experiments with picobarn-level cross sections. A total of 15 decay chains were observed and were assigned to the decay of 288-291114. A new a-decay branch in (281)Ds was observed, leading to the new nucleus (277)Hs.
28.	Graeger, R., et al. (författare) Experimental Study of the 238U(36S,3-5n)269-271Hs Reaction Leading to the Observation of 270Hs 2010 Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 81:6 Tidskriftsartikel (refereegranskat)abstract The deformed doubly magic nucleus (270)Hs has so far only been observed as the four-neutron (4n) evaporation residue of the reaction Mg-26+Cm-248, where a maximum cross section of 3 pb was measured. Theoretical studies on the formation of (270)Hs in the 4n evaporation channel of fusion reactions with different entrance channel asymmetry in the framework of a two-parameter Smoluchowski equation predict that the reactions Ca-48+Ra-226 and S-36+U-238 result in higher cross sections due to lower reaction Q values, in contrast to simple arguments based on the reaction asymmetry, which predict opposite trends. Calculations using HIVAP predict cross sections for the reaction S-36+U-238 that are similar to those of the Mg-26+Cm-248 reaction. Here, we report on the first measurement of evaporation residues formed in the complete nuclear fusion reaction S-36+U-238 and the observation of (270)Hs, which is produced in the 4n evaporation channel, with a measured cross section of 0.8(-0.7)(+2.6) pb at 51-MeV excitation energy. The one-event cross-section limits (68% confidence level) for the 3n, 4n, and 5n evaporation channels at 39-MeV excitation energy are 2.9 pb, while the cross-section limits of the 3n and 5n channel at 51 MeV are 1.5 pb. This is significantly lower than the 5n cross section of the Mg-26+Cm-248 reaction at similar excitation energy.
29.	Khuyagbaatar, J., et al. (författare) 48Ca+249Bk Fusion Reaction Leading to Element Z=117: Long-Lived α-Decaying 270Db and Discovery of 266Lr 2014 Ingår i: Physical Review Letters. - 1079-7114. ; 112:17 Tidskriftsartikel (refereegranskat)abstract The superheavy element with atomic number Z=117 was produced as an evaporation residue in the 48Ca+249Bk fusion reaction at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. The radioactive decay of evaporation residues and their α-decay products was studied using a detection setup that allowed measuring decays of single atomic nuclei with half-lives between sub-μs and a few days. Two decay chains comprising seven α decays and a spontaneous fission each were identified and are assigned to the isotope 294-117 and its decay products. A hitherto unknown α-decay branch in 270Db (Z=105) was observed, which populated the new isotope 266Lr (Z=103). The identification of the long-lived (T1/2=1.0+1.9−0.4 h) α-emitter 270Db marks an important step towards the observation of even more long-lived nuclei of superheavy elements located on an “island of stability.”
30.	Khuyagbaatar, J., et al. (författare) Fission in the landscape of heaviest elements: Some recent examples 2016 Ingår i: Nobel Symposium NS 160 – Chemistry and Physics of Heavy and Superheavy Elements. - : EDP Sciences. - 9782759890118 ; 131 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.
31.	Khuyagbaatar, J., et al. (författare) Fusion reaction 48Ca + 249Bk leading to formation of the element Ts (Z=117) 2019 Ingår i: Physical Review C. - 2469-9985. ; 99:5 Tidskriftsartikel (refereegranskat)abstract The heaviest currently known nuclei, which have up to 118 protons, have been produced in 48Ca induced reactions with actinide targets. Among them, the element tennessine (Ts), which has 117 protons, has been synthesized by fusing 48Ca with the radioactive target 249Bk, which has a half-life of 327 d. The experiment was performed at the gas-filled recoil separator TASCA. Two long and two short α decay chains were observed. The long chains were attributed to the decay of 294Ts. The possible origin of the short-decay chains is discussed in comparison with the known experimental data. They are found to fit with the decay chain patterns attributed to 293Ts. The present experimental results confirm the previous findings at the Dubna Gas-Filled Recoil Separator on the decay chains originating from the nuclei assigned to Ts.
32.	Khuyagbaatar, J., et al. (författare) New Short-Lived Isotope 221U and the Mass Surface Near N=126 2015 Ingår i: Physical Review Letters. - 1079-7114. ; 115:24 Tidskriftsartikel (refereegranskat)abstract Two short-lived isotopes 221U and 222U were produced as evaporation residues in the fusion reaction 50Ti+176Yb at the gas-filled recoil separator TASCA. An α decay with an energy of Eα=9.31(5) MeV and half-life T1/2=4.7(7) μs was attributed to 222U. The new isotope 221U was identified in α-decay chains starting with Eα=9.71(5) MeV and T1/2=0.66(14) μs leading to known daughters. Synthesis and detection of these unstable heavy nuclei and their descendants were achieved thanks to a fast data readout system. The evolution of the N=126 shell closure and its influence on the stability of uranium isotopes are discussed within the framework of α-decay reduced width.
33.	Khuyagbaatar, J., et al. (författare) Study of the 48Ca + 249Bk Fusion Reaction Leading to Element Z = 117: Long-lived Alpha-decaying 270Db and Discovery of 266Lr 2014 Ingår i: GSI Report. ; 2014-1, s. 125-125 Bokkapitel (refereegranskat)
34.	Khuyagbaatar, J., et al. (författare) Study of the Average Charge States of 188Pb and 252,254No Ions at the Gas-filled Separator TASCA 2012 Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 689, s. 40-46 Tidskriftsartikel (refereegranskat)abstract The average charge states of Pb-188 and No-252,No-254 ions in dilute helium gas were measured at the gas-filled recoil separator TASCA. Hydrogen gas was also used as a filling gas for measurements of the average charge state of No-254. Helium and hydrogen gases at pressures from 0.2 mbar to 2.0 mbar were used. A strong dependence of the average charge state on the pressure of the filling gases was observed for both, helium and hydrogen. The influence of this dependence, classically attributed to the so-called "density effect", on the performance of TASCA was investigated. The average charge states of No-254 ions were also measured in mixtures of helium and hydrogen gases at low gas pressures around 1.0 mbar. From the experimental results simple expressions for the prediction of average charge states of heavy ions moving in rarefied helium gas, hydrogen gas, and in their mixture were derived. (C) 2012 Elsevier B.V. All rights reserved.
35.	Khuyagbaatar, J., et al. (författare) The Superheavy Element Search Campaigns at TASCA 2013 Ingår i: GSI Report. - 0171-4546. ; 2013-1, s. 131-131 Bokkapitel (refereegranskat)
36.	Rudolph, Dirk, et al. (författare) Alpha-Photon Coincidence Spectroscopy Along Element 115 Decay Chains 2014 Ingår i: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 45, s. 263-272 Tidskriftsartikel (refereegranskat)abstract Produced in the reaction 48Ca+243Am, thirty correlated α-decay chains were observed in an experiment conducted at the GSI Helmholzzentrum für Schwerionenforschung, Darmstadt, Germany. The decay chains are basically consistent with previous findings and are considered to originate from isotopes of element 115 with mass numbers 287, 288, and 289. A set-up aiming specifically for high-resolution charged particle and photon coincidence spectroscopy was placed behind the gas-filled separator TASCA. For the first time, γ rays as well as X-ray candidates were observed in prompt coincidence with the α-decay chains of element 115.
37.	Rudolph, Dirk, et al. (författare) Element 115 Studied with TASISpec 2014 Ingår i: GSI Report. ; 2014-1, s. 126-126 Bokkapitel (refereegranskat)
38.	Rudolph, Dirk, et al. (författare) Recoil-alpha-fission and Recoil-alpha-alpha-fission Chains Stemming from Element 115 2015 Ingår i: GSI Report. ; 2015-1, s. 180-180 Bokkapitel (refereegranskat)
39.	Rudolph, Dirk, et al. (författare) Selected Spectroscopic Results on Element 115 Decay Chains 2015 Ingår i: Journal of Radioanalytical and Nuclear Chemistry. - : Springer Science and Business Media LLC. - 0236-5731 .- 1588-2780. ; 303:2, s. 1185-1190 Tidskriftsartikel (refereegranskat)abstract Thirty correlated alpha-decay chains were observed in an experiment studying the fusion-evaporation reaction 48Ca + 243Am at the GSI Helmholtzzentrum f¨ur Schwerionenforschung. The decay characteristics of the majority of these 30 chains are consistent with previous observations and interpretations of such chains to originate from isotopes of element Z = 115. High-resolution alpha-photon coincidence spectroscopy in conjunction with comprehensive Monte-Carlo simulations allow to propose excitation schemes of atomic nuclei of the heaviest elements, thereby probing nuclear structure models near the ‘Island of Stability’ with unprecedented experimental precision.
40.	Rudolph, Dirk, et al. (författare) Spectroscopy of Element 115 Decay Chains 2013 Ingår i: Physical Review Letters. - 1079-7114. ; 111:11 Tidskriftsartikel (refereegranskat)abstract A high-resolution , X-ray and gamma-ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum für Schwerionenforschung. Thirty correlated alpha-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z = 115. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z > 112. Comprehensive Monte-Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.
41.	Venhart, M., et al. (författare) Decay Study of 246Fm at SHIP 2011 Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 47:2 Tidskriftsartikel (refereegranskat)abstract The decay chain of Fm-246 has been investigated employing the SHIP separator at GSI Darmstadt. The Fm-246 nuclei were produced via the Ar-40(Pb-208, 2n)Fm-246 fusion-evaporation reaction. Improved values of the half-life, T-1/2 = 1.54(4) s, and of the spontaneous fission branching ratio, b(SF) = 0.068(6), of Fm-246 were obtained. The beta(+)/electron capture branching ratio, b(EC) = 0.39(3), of Cf-242 was deduced. Possible structures of high-K states in Fm-246 are discussed within the framework of a model calculation based on the Woods-Saxon potential.
42.	Yakushev, A., et al. (författare) Chemical Study of Fl, Cn, their Lighter Homologs and Rn at TASCA 2015 Ingår i: GSI Report. ; 2015-1, s. 179-179 Bokkapitel (refereegranskat)
43.	Yakushev, A., et al. (författare) First Study on Nihonium (Nh, Element 113) Chemistry at TASCA 2021 Ingår i: Frontiers in Chemistry. - : Frontiers Media SA. - 2296-2646. ; 9 Tidskriftsartikel (refereegranskat)abstract Nihonium (Nh, element 113) and flerovium (Fl, element 114) are the first superheavy elements in which the 7p shell is occupied. High volatility and inertness were predicted for Fl due to the strong relativistic stabilization of the closed 7p1/2 sub-shell, which originates from a large spin-orbit splitting between the 7p1/2 and 7p3/2 orbitals. One unpaired electron in the outermost 7p1/2 sub-shell in Nh is expected to give rise to a higher chemical reactivity. Theoretical predictions of Nh reactivity are discussed, along with results of the first experimental attempts to study Nh chemistry in the gas phase. The experimental observations verify a higher chemical reactivity of Nh atoms compared to its neighbor Fl and call for the development of advanced setups. First tests of a newly developed detection device miniCOMPACT with highly reactive Fr isotopes assure that effective chemical studies of Nh are within reach.
44.	Yakushev, A., et al. (författare) On the adsorption and reactivity of element 114, flerovium 2022 Ingår i: Frontiers in Chemistry. - : Frontiers Media SA. - 2296-2646. ; 10 Tidskriftsartikel (refereegranskat)abstract Flerovium (Fl, element 114) is the heaviest element chemically studied so far. To date, its interaction with gold was investigated in two gas-solid chromatography experiments, which reported two different types of interaction, however, each based on the level of a few registered atoms only. Whereas noble-gas-like properties were suggested from the first experiment, the second one pointed at a volatile-metal-like character. Here, we present further experimental data on adsorption studies of Fl on silicon oxide and gold surfaces, accounting for the inhomogeneous nature of the surface, as it was used in the experiment and analyzed as part of the reported studies. We confirm that Fl is highly volatile and the least reactive member of group 14. Our experimental observations suggest that Fl exhibits lower reactivity towards Au than the volatile metal Hg, but higher reactivity than the noble gas Rn.
45.	Yakushev, A., et al. (författare) Superheavy Element Flerovium (Element 114) Is a Volatile Metal 2014 Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 1520-510X .- 0020-1669. ; 53:3, s. 1624-1629 Tidskriftsartikel (refereegranskat)abstract The electronic structure of superheavy elements (Z ≥ 104) and their chemical properties are dominated by relativistic effects. Recently two superheavy elements were recognized by the IUPAC and named flerovium (Fl, Z = 114) and livermorium (Lv, Z = 116). Fl is the heaviest element with which chemical experiments were performed. Here, we report on experiments that help answering the long-standing question whether Fl behaves rather like a noble gas or like a metal.
46.	Yakushev, A., et al. (författare) Superheavy Element Flerovium is the Heaviest Volatile Metal 2013 Ingår i: GSI Report. - 0171-4546. ; 2013-1, s. 132-132 Bokkapitel (refereegranskat)
47.	Götz, S., et al. (författare) Rapid extraction of short-lived isotopes from a buffer gas cell for use in gas-phase chemistry experiments, Part II : On-line studies with short-lived accelerator-produced radionuclides 2021 Ingår i: Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 507, s. 27-35 Tidskriftsartikel (refereegranskat)abstract A novel combination of advanced gas-chromatography and detection systems coupled to a buffer-gas cell was characterized on-line to allow gas-phase chemical studies of accelerator-produced short-lived α-decaying mercury, francium, and astatine isotopes. These were produced in 40Ar- and 48Ca-induced nuclear fusion–evaporation reactions, subsequently isolated in the recoil separators MARS at Texas A&M University, USA, and TASCA at GSI Darmstadt, Germany, before being thermalized in a buffer-gas-stopping cell. From the latter, the nuclear reaction products were extracted into gas-phase chromatographic systems, suitable for registering α-decaying short-lived radionuclides, such as isotopes of superheavy elements. Efficiencies of 21(3)% for 204-209Fr were reached for the extraction into the optimized miniCOMPACT gas-chromatography setup, indicating that this technique enables the identification of isotopes of volatile as well as non-volatile elements. These studies guide the path towards chemical investigations of superheavy elements beyond flerovium, which are out of reach with currently used setups.
48.	Schöpf, Julia, et al. (författare) Multi-omic and functional analysis for classification and treatment of sarcomas with FUS-TFCP2 or EWSR1-TFCP2 fusions 2024 Ingår i: Nature Communications. - 2041-1723. ; 15, s. 1-17 Tidskriftsartikel (refereegranskat)abstract Linking clinical multi-omics with mechanistic studies may improve the understanding of rare cancers. We leverage two precision oncology programs to investigate rhabdomyosarcoma with FUS/EWSR1-TFCP2 fusions, an orphan malignancy without effective therapies. All tumors exhibit outlier ALK expression, partly accompanied by intragenic deletions and aberrant splicing resulting in ALK variants that are oncogenic and sensitive to ALK inhibitors. Additionally, recurrent CKDN2A/MTAP co-deletions provide a rationale for PRMT5-targeted therapies. Functional studies show that FUS-TFCP2 blocks myogenic differentiation, induces transcription of ALK and truncated TERT, and inhibits DNA repair. Unlike other fusion-driven sarcomas, TFCP2-rearranged tumors exhibit genomic instability and signs of defective homologous recombination. DNA methylation profiling demonstrates a close relationship with undifferentiated sarcomas. In two patients, sarcoma was preceded by benign lesions carrying FUS-TFCP2, indicating stepwise sarcomagenesis. This study illustrates the potential of linking precision oncology with preclinical research to gain insight into the classification, pathogenesis, and therapeutic vulnerabilities of rare cancers.
49.	Baldwin, H, et al. (författare) Neuroanatomical heterogeneity and homogeneity in individuals at clinical high risk for psychosis 2022 Ingår i: Translational psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 12:1, s. 297- Tidskriftsartikel (refereegranskat)abstract Individuals at Clinical High Risk for Psychosis (CHR-P) demonstrate heterogeneity in clinical profiles and outcome features. However, the extent of neuroanatomical heterogeneity in the CHR-P state is largely undetermined. We aimed to quantify the neuroanatomical heterogeneity in structural magnetic resonance imaging measures of cortical surface area (SA), cortical thickness (CT), subcortical volume (SV), and intracranial volume (ICV) in CHR-P individuals compared with healthy controls (HC), and in relation to subsequent transition to a first episode of psychosis. The ENIGMA CHR-P consortium applied a harmonised analysis to neuroimaging data across 29 international sites, including 1579 CHR-P individuals and 1243 HC, offering the largest pooled CHR-P neuroimaging dataset to date. Regional heterogeneity was indexed with the Variability Ratio (VR) and Coefficient of Variation (CV) ratio applied at the group level. Personalised estimates of heterogeneity of SA, CT and SV brain profiles were indexed with the novel Person-Based Similarity Index (PBSI), with two complementary applications. First, to assess the extent of within-diagnosis similarity or divergence of neuroanatomical profiles between individuals. Second, using a normative modelling approach, to assess the ‘normativeness’ of neuroanatomical profiles in individuals at CHR-P. CHR-P individuals demonstrated no greater regional heterogeneity after applying FDR corrections. However, PBSI scores indicated significantly greater neuroanatomical divergence in global SA, CT and SV profiles in CHR-P individuals compared with HC. Normative PBSI analysis identified 11 CHR-P individuals (0.70%) with marked deviation (>1.5 SD) in SA, 118 (7.47%) in CT and 161 (10.20%) in SV. Psychosis transition was not significantly associated with any measure of heterogeneity. Overall, our examination of neuroanatomical heterogeneity within the CHR-P state indicated greater divergence in neuroanatomical profiles at an individual level, irrespective of psychosis conversion. Further large-scale investigations are required of those who demonstrate marked deviation.
50.	Haas, SS, et al. (författare) Normative Modeling of Brain Morphometry in Clinical High Risk for Psychosis 2024 Ingår i: JAMA PSYCHIATRY. - 2168-622X .- 2168-6238. ; 81:1, s. 77-88 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)

Skapa referenser, mejla, bekava och länka

Länka till träfflistan

Träfflista för sökning "WFRF:(Kindler B.) "

Avgränsa träffmängd

År