SwePub - search: WFRF:(Baktash C.)

Enumeration	Reference	Cover	Find
1.	Bruce, A. M., et al. (author) Two-neutron alignment and shape changes in As-69 2000 In: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 6202:2 Journal article (peer-reviewed)abstract The nucleus As-69 was Studied using the Ca-40(S-32,3p)As-69 reaction at a beam energy of 105 MeV. An extension of the band built on the g(9/2) orbital was observed to exhibit a band crossing at a rotational frequency of 0.511 MeV with an associated alignment of 7 (h) over bar. This alignment is interpreted as being due to a pair of g(9/2) neutrons. Total Routhian surface calculations have been carried out which confirm that the shape of this nucleus changes from oblate at low spin to a triaxial prolate shape at intermediate spin.
2.	Yu, C. H., et al. (author) Comparison of Superdeformed Bands in 61Zn and 60Zn: Possible Evidence for T=0 Pairing 1999 In: Physical Review C (Nuclear Physics). - 0556-2813. ; 60:3 Journal article (peer-reviewed)abstract The yrast superdeformed band in Zn-61 has been established using Si-28(Ar-36, 2pn)Zn-61 and Ca-40(Si-29, 2 alpha)Zn-61 fusion-evaporation reactions. The excitation energy of this band was determined via two transitions that link this band to the normally deformed states. Lifetime analysis of this band resulted in a quadrupole moment of Q(t) = 3.0 +/- (0.5)(0.4)e b, which corresponds to a deformation of beta(2) = 0.50+/-(0.07)(0.06). A comparison of the J((2)) dynamical moments of inertia of the yrast superdeformed band in Zn-61 with those in Zn-60 shows a nearly complete blocking of the observed alignment in Zn-60, indicating that T=0 proton-neutron pair correlations may be present in Zn-60. [S0556-2813(99)51109-6].
3.	Andersson, Lise-Lotte, et al. (author) Extensive Gamma-ray Spectroscopy of Normally and Superdeformed Structures in 61Cu 2008 In: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 36:3, s. 251-278 Journal article (peer-reviewed)abstract A largely extended experimental knowledge of the Cu-61(29)32 nucleus has been obtained from three experiments. Excited states in Cu-61 were produced via the fusion-evaporation reaction Si-28(Ar-36, 3p)Cu-61. In addition to the Ge array GAMMASPHERE, neutron and charged-particle detectors placed around the target position were used for high-performance particle spectroscopy. The constructed level scheme includes more than 160 energy levels and 320 gamma-ray transitions belonging to both normally deformed as well as superdeformed rotational structures. The multipolarities have been determined for the gamma-ray transitions and as a result spin-parity assignments are given for nearly all energy levels. Experimental results in the normally deformed region are compared with predictions from large-scale shell model calculations. The collective structures are compared with results from cranked Nilsson-Strutinsky calculations. The results reveal the need to modify the standard Nilsson parameters in the mass A similar to 60 region.
4.	Gellanki, Jnaneswari, et al. (author) Characterization of Superdeformed Bands in 62Zn 2009 In: Physical Review C (Nuclear Physics). - 0556-2813. ; 80:5 Journal article (peer-reviewed)abstract Combined data from four fusion-evaporation reaction experiments were utilized to investigate deformed and superdeformed structures in Zn-62(30)32. Combination of the Gammasphere gamma-ray spectrometer and ancillary particle detection systems allowed for the connection of rotational bands to well-known, low-lying excited states in Zn-62, as well as spectroscopy of discrete high-spin states reaching excitation energies of E-x=42.5 MeV. Four well- or superdeformed bands in Zn-62 are characterized and described by means of cranked Nilsson-Strutinsky calculations.
5.	Johansson, Emma, et al. (author) Prompt Proton Decay and Deformed Bands in 56Ni 2008 In: Physical Review C (Nuclear Physics). - 0556-2813. ; 77:6 Journal article (peer-reviewed)abstract High-spin states in the doubly magic N=Z nucleus Ni-56 have been investigated with three fusion-evaporation reaction experiments. New gamma-ray transitions are added, and a confirmation of a previously suggested prompt proton decay from a rotational band in Ni-56 into the ground state of Co-55 is presented. The rotational bands in Ni-56 are discussed within the framework of cranked Nilsson-Strutinsky calculations.
6.	Svensson, C. E., et al. (author) Collective rotational motion in the N=Z nucleus 36Ar 2001 In: Nuclear Physics A. - 0375-9474. ; 682:1-4, s. 1-11 Journal article (peer-reviewed)abstract A superdeformed rotational band has been identified in the N = Z nucleus 36Ar, firmly linked to known low-spin states, and observed to its high-spin termination at Iπ = 16+. Lifetime measurements by the Doppler shift attenuation method establish a large low-spin deformation (β2 ≈ 0.46) and a decrease in the collectivity as the band approaches termination. Comparisons with cranked Nilsson-Strutinsky and large-scale spherical shell model calculations lead to a consistent description of the band based on a configuration in which four particles are promoted to the pf shell. With two major shells active for both protons and neutrons, yet a valence space dimension small enough to be approached from the shell model perspective, this band offers an excellent opportunity to investigate the microscopic structure of collective rotational motion in nuclei.
7.	Svensson, C. E., et al. (author) Decay Out of the Doubly Magic Superdeformed Band in the N=Z Nucleus 60Zn 1999 In: Physical Review Letters. - 1079-7114. ; 82:17, s. 3400-3403 Journal article (peer-reviewed)abstract The doubly magic superdeformed band in the N = Z nucleus Zn-60 has been identified. Linking transitions connecting this band to the yrast line provide the first spin, parity, and excitation energy measurements for superdeformed states in the A similar to 60 region. The stretched-E2 character and relatively large B(E2) values of these transitions suggest a nonstatistical decay-out process.
8.	Svensson, C. E., et al. (author) Smooth Termination of Rotational Bands in 62Zn: Evidence for a Loss of Collectivity 1998 In: Physical Review Letters. - 1079-7114. ; 80:12, s. 2558-2561 Journal article (peer-reviewed)abstract Two sets of strongly coupled rotational bands have been identified in Zn-62. These bands have been observed up to the terminating states of their respective configurations. Lifetime measurements indicate that the transition quadrupole moments in these bands decrease as termination is approached. These results establish the first terminating states of rotational bands in the A similar to 60 mass region and confirm the predicted loss of collectivity associated with smooth band termination.
9.	Svensson, C. E., et al. (author) Superdeformation in the N = z Nucleus 36Ar : Experimental, deformed mean field, and spherical shell model descriptions 2000 In: Physical Review Letters. - 0031-9007. ; 85:13, s. 2693-2696 Journal article (peer-reviewed)abstract A superdeformed rotational band has been identified in 36Ar, linked to known low-spin states, and observed to its high-spin termination at Iπ = 16+. Cranked Nilsson-Strutinsky and spherical shell model calculations assign the band to a configuration in which four pf-shell orbitals are occupied, leading to a low-spin deformation β2 ≈ 0.45. Two major shells are active for both protons and neutrons, yet the valence space remains small enough to be confronted with the shell model. This band thus provides an ideal case to study the microscopic structure of collective rotational motion.
10.	Torres, D. A., et al. (author) Deformations and Magnetic Rotations in the 60Ni Nucleus 2008 In: Physical Review C (Nuclear Physics). - 0556-2813. ; 78:5 Journal article (peer-reviewed)abstract Data from three experiments using the heavy-ion fusion evaporation-reaction Ar-36+Si-28 have been combined to study high-spin states in the residual nucleus Ni-60, which is populated via the evaporation of four protons from the compound nucleus Ge-64. The GAMMASPHERE array was used for all the experiments in conjunction with a 4 pi charged-particle detector arrays (MICROBALL, LUWUSIA) and neutron detectors (NEUTRON SHELL) to allow for the detection of. rays in coincidence with the evaporated particles. An extended Ni-60 level scheme is presented, comprising more than 270 gamma-ray transitions and 110 excited states. Their spins and parities have been assigned via directional correlations of gamma rays emitted from oriented states. Spherical shell-model calculations in the fp-shell characterize some of the low-spin states, while the experimental results of the rotational bands are analyzed with configuration-dependent cranked Nilsson-Strutinsky calculations.
11.	Yu, C. H., et al. (author) Superdeformed and Highly Deformed Bands in 65Zn and Neutron-proton Interactions in Zn Isotopes 2000 In: Physical Review C (Nuclear Physics). - 0556-2813. ; 62:4 Journal article (peer-reviewed)abstract Superdeformed and highly deformed rotational bands were established in Zn-65 using the Ca-40(Si-29,4p)Zn-65 reaction, and averaged quadrupole moments were measured for two of these bands. The configurations of these bands were assigned based on Hartree-Fock calculations. One of the three bands exhibits at low (h) over bar omega a rise in the J((2)) dynamic moments of inertia that is similar to the alignment gain observed in Zn-60. A comparison of the rotational band configurations and their J((2)) moments of inertia for light Zn isotopes suggests that the rise in J((2)) is most likely caused by np interactions associated with the valence protons and neutrons occupying the g(9/2) intruder orbits.
12.	Aharonian, F., et al. (author) HESS Follow-up Observations of GRB 221009A 2023 In: Astrophysical Journal Letters. - : Institute of Physics Publishing (IOPP). - 2041-8205 .- 2041-8213. ; 946:1 Journal article (peer-reviewed)abstract GRB 221009A is the brightest gamma-ray burst (GRB) ever detected. To probe the very-high-energy (VHE; >100 GeV) emission, the High Energy Stereoscopic System (H.E.S.S.) began observations 53 hr after the triggering event, when the brightness of the moonlight no longer precluded observations. We derive differential and integral upper limits using H.E.S.S. data from the third, fourth, and ninth nights after the initial GRB detection, after applying atmospheric corrections. The combined observations yield an integral energy flux upper limit of f(UL)(95%)=9.7x10(-12)ergcm(-2)s(-1) E-thr = 650 GeV. The constraints derived from the H.E.S.S. observations complement the available multiwavelength data. The radio to X-ray data are consistent with synchrotron emission from a single electron population, with the peak in the spectral energy distribution occurring above the X-ray band. Compared to the VHE-bright GRB 190829A, the upper limits for GRB 221009A imply a smaller gamma-ray to X-ray flux ratio in the afterglow. Even in the absence of a detection, the H.E.S.S. upper limits thus contribute to the multiwavelength picture of GRB 221009A, effectively ruling out an IC-dominated scenario.
13.	Aharonian, F., et al. (author) TeV flaring activity of the AGN PKS 0625-354 in November 2018 2024 In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 683 Journal article (peer-reviewed)abstract Most gamma-ray detected active galactic nuclei are blazars with one of their relativistic jets pointing towards the Earth. Only a few objects belong to the class of radio galaxies or misaligned blazars. Here, we investigate the nature of the object PKS 0625-354, its gamma-ray flux and spectral variability and its broad-band spectral emission with observations from H.E.S.S., Fermi-LAT, Swift-XRT, and UVOT taken in November 2018. The H.E.S.S. light curve above 200 GeV shows an outburst in the first night of observations followed by a declining flux with a halving time scale of 5.9 h. The gamma gamma-opacity constrains the upper limit of the angle between the jet and the line of sight to similar to 10 degrees. The broad-band spectral energy distribution shows two humps and can be well fitted with a single-zone synchrotron self Compton emission model. We conclude that PKS 0625-354, as an object showing clear features of both blazars and radio galaxies, can be classified as an intermediate active galactic nuclei. Multi-wavelength studies of such intermediate objects exhibiting features of both blazars and radio galaxies are sparse but crucial for the understanding of the broad-band emission of gamma-ray detected active galactic nuclei in general.
14.	Andreoiu, Corina, et al. (author) Yrast Superdeformed Band in 59Cu 2000 In: Physical Review C (Nuclear Physics). - 0556-2813. ; 62:5, s. 513011-513015 Journal article (peer-reviewed)abstract High-spin states in 59Cu were populated using the fusion-evaporation reactions 28Si+40Ca at a beam energy of 125 MeV and 36Ar+28Si at a beam energy of 143 MeV. The Gammasphere array in conjunction with ancillary detector systems allowed for the identification of a superdeformed rotational band in 59Cu, which was firmly linked to low-spin yrast states. Using directional correlations of oriented states, a spin-parity assignment of Iπ = 25/2+ to the band head was possible. The average quadrupole moment of the band is measured to be Qt = (2.24±0.40) e b. The characteristics of the band are compared to neighboring nuclei and predictions of different mean-field theories.
15.	Johansson, Emma, et al. (author) Thorough Gamma-ray and Particle Decay Investigations of 58Ni 2009 In: Physical Review C (Nuclear Physics). - 0556-2813. ; 80:1 Journal article (peer-reviewed)abstract The combined data from three fusion-evaporation reaction experiments have been utilized to investigate the semi-magic nucleus Ni-58(28)30. To detect gamma rays in coincidence with evaporated particles, the Ge-detector array Gammasphere was used in conjunction with the charged-particle detectors Microball and LuWuSiA (the Lund Washington University Silicon Array), and a neutron detector array. The results yield a significantly extended level scheme of Ni-58 comprising some 340 gamma-ray transitions and include a total of at least 14 discrete particle decays into excited states of the daughter nuclei Fe-54 and Co-57. The level scheme is compared with large-scale shell-model calculations and cranked Nilsson-Strutinsky calculations.
16.	Ward, D., et al. (author) Band Structure of 68Ge 2001 In: Physical Review C (Nuclear Physics). - 0556-2813. ; 63:1 Journal article (peer-reviewed)abstract The nucleus Ge-68 has been studied by gamma-ray spectroscopy following its population at high spin in the reaction Ca-40(S-32,4p) Ge-68. The reaction channel was selected with the Microball array and gamma rays were detected with the Gammasphere array. The level scheme is very complex, reflecting the many different, and presumably mixed, excitation modes in this nucleus. Nevertheless, there appear to be some simplifications in the spin range above 18 (h) over bar where we have identified a superdeformed band and several terminating bands. The results are compared with a cranked Nilsson-Strutinsky model without pairing.
17.	Andersson, T., et al. (author) High-spin States in the A=39 Mirror Nuclei 39Ca and 39K 1999 In: European Physical Journal A. Hadrons and Nuclei. - 1434-6001. ; 6, s. 5-8 Journal article (peer-reviewed)abstract High-spin states of the mass A = 39 mirror pair K-39 and Ca-39 were investigated via the fusion-evaporation reaction Si-28+O-16 at 125 MeV beam energy. The GAMMASPHERE array in conjunction with the 4 pi charged-particle detector array MICROBALL and neutron detectors was used to detect gamma rays in coincidence with evaporated light particles. The results of the first high-spin study of the T-z = -1/2 nucleus Ca-39 are discussed in terms of mirror symmetry and compared to spherical shell-model calculations in the 1d(3/2)-1f(7/2) configuration space.
18.	Chiara, C. J., et al. (author) Probing sd-fp Cross-shell Interactions via Terminating Configurations in 42Sc,43Sc 2007 In: Physical Review C (Nuclear Physics). - 0556-2813. ; 75:5 Journal article (peer-reviewed)abstract An experimental study of the lower fp-shell nuclei Sc-42,Sc-43 was performed via alpha pn and alpha p evaporation, respectively, from Ne-20 + Si-28 and Mg-24 + Mg-24 fusion-evaporation reactions. The experiments were conducted with the Gammasphere and Microball detector arrays. The level schemes of both nuclei have been extended considerably. Terminating states associated with the f(7/2)(n) and d(3/2)(-1)f(7/2)(n+1) configurations were identified in each nuclide and incorporated into detailed comparisons with neighboring nuclei and with shell model calculations. The energy differences between the terminating states provide a test of the sd-fp cross-shell interactions in these calculations.
19.	LaFosse, D R, et al. (author) Search for hyperdeformation in Gd-146,Gd-147 1996 In: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 54:4, s. 1585-1588 Journal article (peer-reviewed)abstract A search was undertaken to look for evidence of hyperdeformation in Gd-146,Gd-147. Three experiments employing Gammasphere for gamma-ray detection coupled with the Microball for channel selection via charged particle detection were carried out with increasing detection sensitivity and statistics. No definitive evidence for band structures that could be assigned to hyperdeformation could be found. Candidates previously reported are shown not to have properties consistent with a band structure.
20.	Lipoglavsek, M., et al. (author) First Observation of Excitation Across the 100Sn Core 2001 In: Nuclear Physics, Section A. - 0375-9474. ; 682, s. 399-403 Journal article (peer-reviewed)abstract Excited states of nuclei near the doubly-magic nucleus Sn-100 were studied with the Ni-58+Cr-50 reaction. The experimental setup consisted of the GAMMASPHERE array augmented with light charged-particle and neutron detectors. Excited states were identified for the first time in the proton emitting nucleus Sb-105. Excitations across the N=Z=50 doubly closed shell were observed in Cd-99 and In-101. Some results of large-scale shell-model calculations are discussed.
21.	Svensson, C. E., et al. (author) Observation and Quadrupole Moment Measurement of the First Superdeformed Band in the A~60 Mass Region 1997 In: Physical Review Letters. - 1079-7114. ; 79:7, s. 1233-1236 Journal article (peer-reviewed)abstract A high-spin rotational cascade of six gamma rays has been observed in Zn-62. The quadrupole moment of 2.7(-0.5)(+0.7) e b measured for this band corresponds to a deformation beta(2) = 0.45(-0.07)(+0.10). The properties of this band are in excellent agreement with calculations that predict high-spin superdeformed bands in Zn-62 with deformations beta(2) = 0.41-0.49. These results establish a new region of superdeformation for nuclei with neutron and proton numbers N, Z approximate to 30-32.
22.	Caballero, O L, et al. (author) "Complete" High-Spin Structure of 57Co 2003 In: Physical Review C: covering nuclear physics. ; 67 Journal article (peer-reviewed)abstract A comprehensive high-spin decay scheme has been deduced for 57Co using the Gammasphere Germanium detector array coupled to the 4π charged-particle detector system Microball. Following the fusion-evaporation reaction of 28Si(36Ar,1α3p)57Co at 136 MeV beam energy about 90 excited states have been observed in 57Co, which are connected by some 230 γ-ray transitions. The proposed level scheme reaches 16 MeV excitation energy at a spin of 17ħ–18ħ. With its complexity the level scheme of 57Co appears to be “complete” up to 1 or 2 MeV above the yrast line. This aspect is further investigated through a comparison of the data with spherical shell-model calculations.
23.	Döring, J., et al. (author) Band terminations in the valence space of 86Zr 2000 In: Physical Review C - Nuclear Physics. - 0556-2813. ; 61:3, s. 343101-343106 Journal article (peer-reviewed)abstract High-spin states in 86Zr up to 30+ and 27- were observed via the 58Ni(32S,4p) reaction at 135 MeV beam energy using the combined GAMMASPHERE and MICROBALL systems. Calculations performed with the configuration-dependent shell-correction approach show that these states are built from six g9/2 neutrons and at most four protons excited from the p1/2,p3/2,f5/2 subshells to the g9/2 subshell at small deformation. The highest observed states at 27- and 30+ are interpreted as band-terminating states with the latter having the highest spin available in the valence space for 86Zr.
24.	HUA, PF, et al. (author) SEARCH FOR HYPERDEFORMATION IN GD-146 USING THE MICROBALL AND GAMMASPHERE 1994 In: Abstracts of Papers of the American Chemical Society. - 0065-7727. ; 208, s. 12-NUCL Journal article (peer-reviewed)
25.	Ideguchi, E., et al. (author) Superdeformation in the Doubly Magic Nucleus 40Ca 2001 In: Physical Review Letters. - 1079-7114. ; 87:22 Journal article (peer-reviewed)abstract A rotational band with seven gamma -ray transitions between states with spin 2 (h) over bar and 16 (h) over bar has been observed in the doubly magic, self-conjugate nucleus Ca-40(20)20. The measured transition quadrupole moment of 1.80(-0.29)(+0.39)eb indicates a superdeformed shape with a deformation beta (2) = 0.59(-0.07)(+0.11). The features of this band are explained by cranked relativistic mean field calculations to arise from an 8-particle 8-hole excitation.

Skapa referenser, mejla, bekava och länka

Permalink

Träfflista för sökning "WFRF:(Baktash C.) "

Refine your search

Year