Nuclear Data Sheets for A = 113
This evaluation for A = 113 updates one by J. Blachot, (2005Bl05), published in Nuclear Data Sheets 104, 791 (2005)
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Nuclear Data Sheets for A = 121
The 2000 Nuclear Data Sheets for A = 121 by T. Tamura, with literature cutoff date of July 1,1999 has been updated. The experimental results from various decays and reactions for A=121 mass chain have been compiled and evaluated. The nuclides covered in this evaluation are from {sup 121}Rh to {sup 121}Pr. The data are summarized and presented, together with adopted level schemes.
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Atomic interferometer measurements of Berry and Aharonov-Anandan phases for isolated spins S>(1/2) nonlinearly coupled to external fields
In a recent paper we have studied the peculiar features of the Berry and Aharonov-Anandan geometric phases for isolated spins S{>=}1. We have assumed that they are submitted to a dipole and quadrupole coupling to external E and B fields with the mild restriction E{center_dot}B=0. This implies discrete symmetries leading to remarkable simplifications of the geometry and algebra involved. The aim of the present work is to describe realistic proposals, within the realm of atomic physics, for the verification of some of our most significant theoretical predictions. There are several challenges to be overcome. For alkali-metal atoms, most commonly used in atomic interferometers, the only practical way to generate quadrupole coupling, with a strength comparable to the dipole one, is the ac Stark effect induced by a nearly resonant light beam. One then has to face the instability of the 'dressed' atom hyperfine (hf) level, a candidate for our isolated spin. One deleterious effect is the apparition of an imaginary part in the quadrupole to dipole coupling strength ratio, {lambda}. Fortunately we have found a simple way to get rid of I({lambda}) by an appropriate detuning. We are left with an unstable isolated spin. This implies an upper bound to the quantum cycle duration T{sub c}. In the case of the Berry's phase, T{sub c} has a lower bound due to the necessity of keeping the nonadiabatic corrections below a predefined level. We have found a compromise in the case of the F=2,m=0 {sup 87}Rb ground-state hf level. This is our candidate for the measurement of the somewhat ''exotic'' Berry's phase acquired by the S=2,m=0 state at the end of a quantum cycle involving a rotation of {pi} of the E field--in practice, the linear polarization of the dressing beam --about the B field direction. We have found a way to implement, in a Ramsey-type interferometric measurement, the procedures aimed at controlling the nonadiabatic corrections, as described in detail in our previous theoretical paper. A numerical simulation of our experimental proposal shows that a 0.1% accurate determination of Berry's phase, free of nonadiabatic corrections, can be achieved. Measurements could also be considered for cold {sup 52}Cr chromium atoms with S=3, where values of {lambda}{approx_equal}1 can be obtained with an instability smaller than in the {sup 87}Rb case, due to a more favorable spectroscopic structure. The F=1,m=1 hf level of the {sup 87}Rb ground state offers the opportunity to extend the measurement of Aharonov-Anandan's phases beyond the case S=(1/2). We construct, using 'light shift', the Hamiltonian H{sub ||}(t) generating a closed circuit in the density-matrix space which satisfies at any time the 'parallel transport' condition, thus making the quantum cycle free from the adiabaticity condition. We also consider the case of half-integer spins (e.g., {sup 201}Hg, {sup 135}Ba, and {sup 137}Ba), with their own specific features. We show how the difference of Berry's phases for states S=(3/2) and S=(1/2), with m=(1/2), can be exploited to achieve a holonomic maximum entanglement of three qubits.
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Decay Properties of {sup 266}Bh and {sup 262}Db Produced in the {sup 248}Cm+{sup 23}Na Reaction - Further Confirmation of the {sup 278}113 Decay Chain
Decay properties of an isotope {sup 266}Bh and its daughter nucleus {sup 262}Db produced by the {sup 248}Cm({sup 23}Na,5n) reaction were studied by using a gas-filled recoil separator coupled with a position-sensitive semiconductor detector. {sup 266}Bh was clearly identified from the correlation of the known nuclide, {sup 262}Db. The obtained decay properties of {sup 266}Bh and {sup 262}Db are consistent with those observed in the {sup 278}113 chain by RIKEN collaboration, which provided further confirmation of the discovery of {sup 278}113.
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Role of angular momentum in the production of complex fragments in fusion and quasifission reactions
The influence of angular momentum on the competition between complete fusion followed by the decay of compound nucleus and quasifission channels is treated within the dinuclear system model. The charge distributions of the products in the reactions {sup 28}Si+{sup 96}Zr, {sup 4}He+{sup 130}Te, and {sup 40}Ca+{sup 82}Kr are predicted at bombarding energies above the Coulomb barrier. The results of calculations for the reactions {sup 93}Nb+{sup 9}Be,{sup 12}C,{sup 27}Al; {sup 84}Kr+{sup 27}Al; {sup 86}Kr+{sup 63}Cu; {sup 139}La+{sup 12}C,{sup 27}Al; and {sup 45}Sc+{sup 65}Cu are compared with the available experimental data.
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Fission fragment mass distributions in reactions forming the {sup 213}Fr compound nucleus
The fission fragment mass angle correlations and mass ratio distributions have been investigated for the two systems {sup 16}O+{sup 197}Au and {sup 27}Al+{sup 186}W, leading to the same compound nucleus {sup 213}Fr around the Coulomb barrier energies. Systematic analysis of the variance of the mass distributions as a function of temperature and angular momentum suggests true compound nuclear fission for both the reactions, indicating the absence of nonequilibrium fission processes.
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Nuclear Data Sheets for A = 168
Nuclear structure data pertaining to all nuclei with mass A=168 (Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt) have been evaluated and incorporated into the ENSDF data file. This evaluation supersedes the previous publication (V.S. Shirley, Nuclear Data Sheets 71, 261 (1994) (literature cutoff date July 1993)) and subsequent ENSDF file revisions for Tb and Dy (C. Baglin, literature cutoff date of 15 June 1999) and Hf (B. Singh, literature cutoff date of 30 April 2001), and includes literature available by 15 June 2010. Since the above evaluations, the first excited states in {sup 168}Pt have been identified (1998Ki20, 2009Go16) and {alpha} decay from {sup 172}Hg has been observed (2009Sa27, 2004Ke06, 1999Se14). New levels in {sup 168}Dy have been excited using the {sup 170}Er({sup 82}Se,{sup 84}Kr{gamma}) reaction (2010So03). (HI,xn{gamma}) studies have significantly expanded our knowledge of level structure in {sup 168}Lu (1999Ka17, 2002Ha33), {sup 168}Ta (2008QiZZ), {sup 168}Yb (1995Fi01), {sup 168}Tm (2007CaZW), {sup 168}Hf (2009Ya21), {sup 168}Os (2001Jo11, 2009Od02) and, for {sup 168}Tm, important information has come also from (d,2n{gamma}) and ({alpha},n{gamma}) reactions (1995Si20). Revised decay schemes are available following new studies of {sup 168}Hf {epsilon} decay (6.7 min) (1997Ba26), {sup 168}Lu {epsilon} decay (1999Ba65), {sup 168}Ta {epsilon} decay (2007Mc08) and {sup 172}Au {alpha} decay (2009Ha42). Significant new information for {sup 168}Er is available from (p,t) (2006Bu09), (d,p) and (t,d) (1996Ma50), ({gamma},{gamma}') (1996Ma18), (136Xe, X{gamma}) (2010Dr02), ({sup 238}U,{sup 238}U{sup '{gamma}}) (2003Wu07) and (n,n{sup '{gamma}}) (1998Be20, 1998Be62) reactions, and the availability of {gamma}{gamma} coin data (1994Ju02, 1996Gi09) for the (n,{gamma}) E=thermal reaction has resulted in some significant level scheme revisions.
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Island of inversion around {sup 64}Cr
We study the development of collectivity in the neutron-rich nuclei around N=40, where the experimental and theoretical evidence suggest a rapid shape change from the spherical to the rotational regime, in analogy to what happens at the island of inversion surrounding {sup 31}Na. Theoretical calculations are performed within the interacting shell-model framework in a large valence space, based on a {sup 48}Ca core, which encompasses the full pf shell for the protons and the 0f{sub 5/2}, 1p{sub 3/2}, 1p{sub 1/2}, 0g{sub 9/2}, and 1d{sub 5/2} orbits for the neutrons. The effective interaction is based on a G matrix obtained from a realistic nucleon-nucleon potential whose monopole part is corrected empirically to produce effective single-particle energies compatible with the experimental data. We find a good agreement between the theoretical results and the available experimental data. We predict the onset of deformation at different neutron numbers for the various isotopic chains. The maximum collectivity occurs in the chromium isotopes where the large deformation regime already starts at N=38. The shell evolution responsible for the observed shape changes is discussed in detail, in parallel to the situation in the N=20 region.
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Precision measurements of proton emission from the ground states of {sup 156}Ta and {sup 160}Re
The decays of the {pi}d{sub 3/2} ground states of {sup 156}Ta and {sup 160}Re have been studied in detail using the GREAT spectrometer. More than 7000 {sup 160}Re nuclei were produced in reactions of 290- and 300-MeV {sup 58}Ni ions with an isotopically enriched {sup 106}Cd target and separated in flight using the RITU separator. The proton and {alpha} decays of the {pi}d{sub 3/2} level were confirmed and the half-life and branching ratios of this state were determined with improved precision to be t{sub 1/2}=611{+-}7 {mu}s and b{sub p}=89{+-}1% and b{sub {alpha}=}11{+-}1%, respectively. The {alpha}-decay branch populated the ground state of {sup 156}Ta, allowing improved values for the proton-decay energy and half-life to be obtained (E{sub p}=1011{+-}5 keV; t{sub 1/2}=106{+-}4 ms). The {beta} decay of this level was identified for the first time and a branching ratio of b{sub {beta}=}29{+-}3% was deduced. The spectroscopic factors deduced from these measurements are compared with predictions.
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High-spin states in the five-valence-particle nucleus {sup 213}Po
Excited states in {sup 213}Po have been populated using the {sup 18}O+ {sup 208}Pb reaction at 85 MeV beam energy and studied with the Euroball IV {gamma} multidetector array. The level scheme has been built up to {approx}2.0 MeV excitation energy and spin I{approx}25/2({h_bar}/2{pi}) from the triple {gamma} coincidence data. Spin and parity values of several yrast states have been assigned from the {gamma} angular properties. The configurations of the yrast states are discussed using results of empirical shell-model calculations and by analogy with the neighboring nuclei. The spin and parity values of several low-spin states of {sup 213}Po previously identified from the {beta} decay of {sup 213}Bi are revised.
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Collectivity at N=40 in neutron-rich {sup 64}Cr
{sup 9}Be-induced inelastic scattering of {sup 62,64,66}Fe and {sup 60,62,64}Cr was performed at intermediate beam energies. Excited states in {sup 64}Cr were measured for the first time. Energies and population patterns of excited states in these neutron-rich Fe and Cr nuclei are compared and interpreted in the framework of large-scale shell-model calculations in different model spaces. Evidence for increased collectivity and for distinct structural changes between the neighboring Fe and Cr isotopic chains near N=40 is presented.
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First observation of high-spin states in {sup 214}Po: Probing the valence space beyond {sup 208}Pb
Excited states in {sup 214}Po have been populated using the {sup 18}O + {sup 208}Pb reaction at 85-MeV beam energy and studied with the Euroball IV {gamma}-multidetector array. The level scheme has been built up to {approx}2.7-MeV excitation energy and spin I=12({h_bar}/2{pi}) from the triple-{gamma} coincidence data. Spin and parity values of most of the observed states have been assigned from the {gamma}-angular properties. The configurations of the yrast states are discussed using results of empirical shell-model calculations and by analogy with the neighboring nuclei. The {sup 214}Po level scheme established in this work constitutes an important step for the determination of the effective nucleon-nucleon interactions beyond N=126.
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Production and Decay of Element 114: High Cross Sections and the New Nucleus {sup 277}Hs
The fusion-evaporation reaction {sup 244}Pu({sup 48}Ca,3-4n){sup 288,289}114 was studied at the new gas-filled recoil separator TASCA. Thirteen correlated decay chains were observed and assigned to the production and decay of {sup 288,289}114. At a compound nucleus excitation energy of E*=39.8-43.9 MeV, the 4n evaporation channel cross section was 9.8{sub -3.1}{sup +3.9} pb. At E*=36.1-39.5 MeV, that of the 3n evaporation channel was 8.0{sub -4.5}{sup +7.4} pb. In one of the 3n evaporation channel decay chains, a previously unobserved {alpha} branch in {sup 281}Ds was observed (probability to be of random origin from background: 0.1%). This {alpha} decay populated the new nucleus {sup 277}Hs, which decayed by spontaneous fission after a lifetime of 4.5 ms.
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How the projectile neutron number influences the evaporation cross section in complete fusion reactions with heavy ions
The influence of the projectile neutron number on the evaporation residue cross sections for the reactions {sup 208}Pb({sup 52,54}Cr,n,2n){sup 258-261}Sg and {sup 208}Pb({sup 48,50}Ti,n,2n){sup 254-257}Rf has been studied within the framework of a fusion-fission statistical model. The results obtained with the kewpie2 code are compared with recent experimental data. The excitation functions represent the experimental results well both in the maximum value and the lactation of the peak. The calculations show that the projectile neutron number greatly influences both the capture cross section and the fusion probability.
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DPUNS--A Differential-Plunger For Lifetime Measurements Of Tagged Exotic/Unbound Nuclear States
This contribution focused on research to measure the lifetimes of unbound nuclear states using a differential-plunger technique combined with recoil-proton decay tagging. The results of the first lifetime measurements of unbound states in the spherical proton emitter, {sup 109}I, were discussed along with the limits to the technique. In order to proceed further, a new differential-plunger device, DPUNS, has been designed and is currently being built at the University of Manchester. DPUNS has been optimised to work with the GREAT/RITU/TDR setup at the University of Jyvaeskylae and the status of the new device is discussed.
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