Intensity profiles of superdeformed bands in Pb isotopes in a two-level mixing model

International Nuclear Information System (INIS)

Wilson, A. N.; Szigeti, S. S.; Rogers, J. I.; Davidson, P. M.; Cardamone, D. M.

2009-01-01

A recently developed two-level mixing model of the decay out of superdeformed bands is applied to examine the loss of flux from the yrast superdeformed bands in 192 Pb, 194 Pb, and 196 Pb. Probability distributions for decay to states at normal deformations are calculated at each level. The sensitivity of the results to parameters describing the levels at normal deformation and their coupling to levels in the superdeformed well is explored. It is found that except for narrow ranges of the interaction strength coupling the states, the amount of intensity lost is primarily determined by the ratio of γ decay widths in the normal and superdeformed wells. It is also found that while the model can accommodate the observed fractional intensity loss profiles for decay from bands at relatively high excitation, it cannot accommodate the similarly abrupt decay from bands at lower energies if standard estimates of the properties of the states in the first minimum are employed

Transition quadrupole moments in the superdeformed band of 40Ca

International Nuclear Information System (INIS)

Chiara, C.J.; Ideguchi, E.; Devlin, M.; LaFosse, D.R.; Lerma, F.; Reviol, W.; Ryu, S.K.; Sarantites, D.G.; Baktash, C.; Galindo-Uribarri, A.; Carpenter, M.P.; Janssens, R.V.F.; Lauritsen, T.; Lister, C.J.; Reiter, P.; Seweryniak, D.; Fallon, P.; Goergen, A.; Macchiavelli, A.O.; Rudolph, D.

2003-01-01

The transition quadrupole moments Q t for the superdeformed band in 40 Ca have been determined through thin-target Doppler-shift attenuation analyses. A best-fit value of Q t =1.30±0.05 e b is obtained when a single value is assumed for the entire band. Fitting separate quadrupole moments for in-band transitions decaying from the high-spin states and the presumably admixed low-spin states results in Q t (high)=1.81 -0.26 +0.41 e b and Q t (low)=1.18 -0.05 +0.06 e b, respectively. Q t values extracted for individual transitions in a Doppler-broadened line-shape analysis also indicate smaller Q t values at lower spins. These results are consistent with the interpretation of this band as an eight-particle-eight-hole superdeformed band with a significant admixture of less-collective configurations at low spins

Entrance-channel effects in the population of superdeformed bands in 147,148Gd

International Nuclear Information System (INIS)

Flibotte, S.; Andrews, H.R.; Drake, T.E.; Galindro-Uribarri, A.; Haas, B.; Janzen, V.P.; Prevost, D.; Radford, D.C.; Rodriguez, J.; Romain, P.; Vivien, J.P.; Waddington, J.C.; Ward, D.; Zwartz, G.

1992-01-01

Discrete superdeformed bands in 147,148 Gd have been populated with asymmetric and symmetric fusion-evaporation reactions. The yields of the superdeformed bands compared with the total yield of the channel exhibit a large increase for symmetric reactions. We suggest an explanation for this effect in terms of the competition between neutron emission and fission at the early stage of the deexcitation process of the composite system

Spins of superdeformed band in {sup 192}Hg

Energy Technology Data Exchange (ETDEWEB)

Lauritsen, T.; Khoo, T.L.; Henry, R.G. [and others

1995-08-01

Determination of the spins of SD states is the most important challenge in the study of superdeformation. Knowledge of the spin will provide crucial information on SD bands, in particular on the fascinating phenomenon of bands with identical energies and moments of inertia. Angular distribution coefficients of the {gamma}rays decaying out of the {sup 192}Hg SD band were determined using Eurogam data. These coefficients, as well as the spectral shape and multiplicity of the spectrum, are compared with the results of calculations, thereby providing a check on these calculations. From the measured decay multiplicity and the calculated average spin removed per photon (0.3 h), we deduce the average spin {bar I}{sub decay} removed by the {gamma} rays connecting SD and normal states. The spin I{sub SD} of the SD band from which the decay occurs is given by I{sub SD} = {bar I} decay + {bar I} ND, where {bar I} ND is the average spin removed by the normal yrast states. The state from which the major decay out of the SD band occurs is found to have spin 9.5 {plus_minus} 0.8 h. Since angular momentum is (quantized), this leads to a spin assignment of 9 or 10 h. The latter value is favored since the yrast band in the SD well must have only even spin values. This constitutes the first deduction of spin from data in the mass 150 and 190 regions. The spin of 10 h agrees with the spin which is inferred from a model, using the observed moment of inertia (Im){sup (2)}{omega}.

Decay from the superdeformed bands in 194Hg

International Nuclear Information System (INIS)

Henry, R.G.; Khoo, T.L.; Carpenter, M.P.

1995-01-01

Superdeformed bands in 194 H g were studied using the early implementation of Gammasphere. The response functions for the Ge detectors were measured for the first time as part of this experiment. Experiments were performed with both a backed target (where the residue stopped in the Au backing) and a thin target (where the residue recoiled into vacuum). This will permit measurements of the decay times of the quasicontinuum γrays. The spectrum in coincidence with the yrast SD band in 194 Hg reveals the same features as found in the quasicontinuum structure in 192 Hg. These features include: statistical γrays feeding the SD band, a pronounced E2 peak from transitions feeding the SD band, a Ml/E2 bump at low energies that is associated with the last stages of feeding of the superdeformed band, and a quasicontinuous distribution from γrays linking SD and normal states, including a sizable clustering of strength around 1.7 MeV. The remarkable similarity of the spectra coincident with SD bands in 192,194 Hg provides additional support for a statistical process for decay out of the SD states. This similarity contrasts with differences observed in the spectrum coincident with the SD band in the odd-even 191 Hg, confirming the predictions about the role of pairing (in normal states) in influencing the shape of the decay-out spectrum

Feeding of the superdeformed yrast band in sup 149 Gd

Energy Technology Data Exchange (ETDEWEB)

Haas, B.; Vivien, J.P.; Beck, F.A.; Benet, P.; Byrski, T.; Curien, D.; Duchene, G.; Gehringer, C.; Merdinger, J.C.; Romain, P. (Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires); Basu, S.K. (Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires Bhabha Atomic Research Centre, Calcutta (India). Variable Energy Cyclotron Centre); Kluge, H. (Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires Hahn-Meitner-Institut Berlin GmbH (Germany, F.R.)); Santos, D. (Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina)); Flibotte, S. (Hahn-Meitner-Institut Berlin GmbH (Germany, F.R.)); Gascon, J.; Taras, P. (Montreal Univ., Quebec (Canada). Lab. de Physique Nucleaire); Bozek, E.; Zuber, K. (Institute of Nuclear Physics, Krakow (Poland))

1990-08-02

The feeding pattern of the superdeformed yrast band in {sup 149}Gd has been found to remain essentially the same, using the {sup 124}Sn+{sup 30}Si reaction at beam energies of 150, 155 and 160 MeV leading to different input angular momenta and excitation energies in the compound nuclear system. This similarity as well as the relative yields of the superdeformed states as a function of beam energy may be understood in terms of the nuclear level density dependence on deformation and the onset of fission. In addition, it has been shown that, at all three beam energies, the selection of high-energy gamma rays does not enhance the yield of the superdeformed yrast states. (orig.).

Band head spin assignment of superdeformed bands in 133Pr using two-parameter formulae

Science.gov (United States)

Sharma, Honey; Mittal, H. M.

2018-03-01

The two-parameter formulae viz. the power index formula, the nuclear softness formula and the VMI model are adopted to accredit the band head spin (I0) of four superdeformed rotational bands in 133Pr. The technique of least square fitting is used to accredit the band head spin for four superdeformed rotational bands in 133Pr. The root mean deviation among the computed transition energies and well-known experimental transition energies are attained by extracting the model parameters from the two-parameter formulae. The determined transition energies are in excellent agreement with the experimental transition energies, whenever exact spins are accredited. The power index formula coincides well with the experimental data and provides minimum root mean deviation. So, the power index formula is more efficient tool than the nuclear softness formula and the VMI model. The deviation of dynamic moment of inertia J(2) against the rotational frequency is also examined.

Superdeformed bands in sub 64 sup 147 Gd sub 83 , a possible test of the existence of octupole correlations in superdeformed bands

Energy Technology Data Exchange (ETDEWEB)

Zuber, K.; Balouka, D.; Beck, F.A.; Byrski, T.; Curien, D.; Duchene, G.; Gehringer, C.; Haas, B.; Merdinger, J.C.; Romain, P.; Santos, D.; Styczen, J.; Vivien, J.P.; Dudek, J.; Szymanski, Z.; Werner, T. (Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires)

1990-12-24

Two discrete superdeformed bands (SD) have been identified in the nucleus {sup 147}Gd. The transitions energies of the SD yrast band lie halfway between the {gamma}-ray energies of the yrast SD band in {sup 146}Gd while the transition energies of the excited band lie half way between the transition energies of the yrast SD band in {sup 148}Gd. These two bands are shown to exhibit the presence of the pseudo SU(3) symmetry and also indicate the possible existence of octupole correlations at large elongations and high spins. (orig.).

Deexcitation of superdeformed bands in the nucleus Tb-151

NARCIS (Netherlands)

Finck, C; Appelbe, D; Beck, FA; Byrski, T; Cullen, D; Curien, D; deFrance, G; Duchene, G; Erturk, S; Haas, B; Khadiri, N; Kharraja, B; Prevost, D; Rigollet, C; Stezowski, O; Twin, P; Vivien, JP; Zuber, K

1997-01-01

The aim of this work is to get more informations about the decay-out of superdeformed bands. One of the best candidates in the mass A similar or equal to 150 region for that kind of research is the nucleus Tb-151. From previous works, it has been established that the first excited band goes lower in

Microscopic study of superdeformed rotational bands in {sup 151} Tb

Energy Technology Data Exchange (ETDEWEB)

El Aouad, N.; Dudek, J.; Li, X.; Luo, W.D.; Molique, H.; Bouguettoucha, A.; Byrski, TH.; Beck, F.; Finck, C.; Kharraja, B. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Dobaczewski, J. [Warsaw Univ. (Poland); Kharraja, B. [Notre Dame Univ., IN (United States). Dept. of Physics

1996-12-31

Structure of eight superdeformed bands in the nucleus {sup 151}Tb is analyzed using the results of the Hartree-Fock and Woods-Saxon cranking approaches. It is demonstrated that far going similarities between the two approaches exit and predictions related to the structure of rotational bands calculated within the two models are nearly parallel. An interpretation scenario for the structure of the superdeformed bands is presented and predictions related to the exit spins are made. Small but systematic discrepancies between experiment and theory, analyzed in terms of the dynamical moments, J{sup (2)}, are shown to exist. The pairing correlations taken into account by using the particle-number-projection technique are shown to increase the disagreement. Sources of these systematic discrepancies are discussed - they are most likely related to the yet not optimal parametrization of the nuclear interactions used. (authors). 60 refs.

Superdeformation

Energy Technology Data Exchange (ETDEWEB)

Stephens, F.S. [Lawrence Berkeley National Lab., CA (United States)

1996-12-31

This talk consists of three parts: an introduction to the current situation regarding superdeformed bands; some recent highlights; and a quick look at the future. Due mainly to the large gamma-ray detectors coming into use, there is a lot going on in this area and the author does not try to include it all here. Rather, after a few general observations the author selects several highlights and tries to discuss those in some depth. Finally the author gives his thoughts as to the future of studying superdeformed nuclei. His definition of superdeformation is rather broad and generally includes nuclei where the long axis is 1.5-2 times longer than the short axis. Typically this is a second minimum in the potential energy surface; the first having smaller (perhaps {open_quotes}normal{close_quotes}) deformation. With this definition there are now five regions of superdeformation known in the heavier elements, having masses centered around 80, 130, 150, 190 and 240, the last of these being the fission isomers discovered more than 30 years ago. Altogether there are around 200 bands presently known in these five regions. The newest region is that around mass 80, where already some 20 bands are known in 10 nuclei. These bands show all the familiar properties seen in the heavier regions: assigned configurations, band crossings, identical bands, etc.

Entrance-channel effects in the population of superdeformed bands in sup 147,148 Gd

Energy Technology Data Exchange (ETDEWEB)

Flibotte, S.; Andrews, H.R.; Drake, T.E.; Galindro-Uribarri, A.; Haas, B.; Janzen, V.P.; Prevost, D.; Radford, D.C.; Rodriguez, J.; Romain, P.; Vivien, J.P.; Waddington, J.C.; Ward, D.; Zwartz, G. (Centre de Recherches Nucleaires, F-67037 Strasbourg CEDEX (France) AECL Research, Chalk River Laboratories, Chalk River, Ontario, K0J 1J0 (Canada) Department of Physics, University of Toronto, Toronto, Ontario, M5S 1A7 (Canada) Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4K1 (Canada))

1992-03-01

Discrete superdeformed bands in {sup 147,148}Gd have been populated with asymmetric and symmetric fusion-evaporation reactions. The yields of the superdeformed bands compared with the total yield of the channel exhibit a large increase for symmetric reactions. We suggest an explanation for this effect in terms of the competition between neutron emission and fission at the early stage of the deexcitation process of the composite system.

Multiple superdeformed bands in sup 194 Hg and their dynamical moments of inertia

Energy Technology Data Exchange (ETDEWEB)

Riley, M.A.; Cullen, D.M.; Alderson, A.; Ali, I.; Fallon, P.; Forsyth, P.D.; Hanna, F.; Mullins, S.M.; Roberts, J.W.; Sharpey-Schafer, J.F.; Twin, P.J. (Liverpool Univ. (UK). Oliver Lodge Lab.); Poynter, R.; Wadsworth, R. (York Univ. (UK). Dept. of Physics); Bentley, M.A.; Bruce, A.M.; Simpson, J. (Science and Engineering Research Council, Daresbury (UK). Daresbury Lab.); Sletten, G. (Niels Bohr Inst., Roskilde (Denmark). Tandem Accelerator Lab.); Nazarewicz, W. (Liverpool Univ. (UK). Oliver Lodge Lab. Politechnika Warszawska (Poland). Inst. Fizyki); Bengtsson, T. (Lund Inst. of Tech. (Sweden). Dept. of Mathematical Physics); Wyss, R. (Manne Siegbahn Inst. of Physics, Stockholm (Sweden))

1990-05-28

Three superdeformed bands have been observed in {sup 194}Hg. The dynamical moment of inertia J{sup (2)} of all three bands is observed to increase by 30-40% over the frequency range {Dirac h}{omega}=0.1-0.4 MeV. This phenomena can be understood in terms of the gradual alignment of pairs of high-j intruder orbitals within the framework of the cranked Woods-Saxon and Nilsson models including pairing. The calculations together with the observed J{sup (2)} behaviour of the three bands indicate that pairing correlations in the superdeformed minimum are rather weak. (orig.).

The collectivity and the de-excitation of the yrast superdeformed band in sup 150 Gd

Energy Technology Data Exchange (ETDEWEB)

Fallon, P.; Alderson, A.; Ali, I.; Cullen, D.M.; Forsyth, P.D.; Riley, M.A.; Roberts, J.W.; Sharpey-Schafer, J.F.; Twin, P.J. (Liverpool Univ. (UK). Oliver Lodge Lab.); Bentley, M.A.; Bruce, A.M. (Science and Engineering Research Council, Daresbury (UK). Daresbury Lab.)

1991-03-28

A Doppler shift attenuation measurement has been carried out to determine the collectivity of the superdeformed band in {sup 150}Gd. The data was found to be consistent with a constant inband quadrupole moment of 17+-3 eb. This corresponds to a quadrupole deformation of {beta}{sub 2}{approx equal}0.58. In addition the measurement has resolved important questions regarding the de-excitation of the band, confirming the rapid de-excitation of the superdeformed band in {sup 150}Gd with more than 80% of the band intensity being lost over one transition. (orig.).

Multiple superdeformed bands in Sr, Y, and Zr nuclei

International Nuclear Information System (INIS)

Reviol, W.; Sarantites, D.G.; Lerma, F.; Devlin, M.; LaFosse, D.R.; Chiara, C.J.; Wyss, R.; Baktash, C.; Jin, H.-Q.; Tabor, S.L.; Soltysik, D.; Clark, R.M.; Lee, I.Y.; Macchiavelli, A.O.; MacLeod, R.W.

2003-01-01

Multiple superdeformed bands in the nuclei 80-83Sr, 82-84Y, and 83,84Zr have been studied in a backed-target experiment using the Gammasphere and Microball detector arrays. For 15 bands in these nuclei, average transition quadrupole moments (Qt) have been measured accurately. Among those are two pairs of 'isospectral' bands and the Qt values obtained in each case are nearly identical. The measured Qt values and dynamical moments of inertia place stringent conditions on configuration assignments for the bands obtained from mean field calculations

Decay from the superdeformed bands in {sup 194}Hg

Energy Technology Data Exchange (ETDEWEB)

Henry, R.G.; Khoo, T.L.; Carpenter, M.P. [and others

1995-08-01

Superdeformed bands in {sup 194}H g were studied using the early implementation of Gammasphere. The response functions for the Ge detectors were measured for the first time as part of this experiment. Experiments were performed with both a backed target (where the residue stopped in the Au backing) and a thin target (where the residue recoiled into vacuum). This will permit measurements of the decay times of the quasicontinuum {gamma}rays. The spectrum in coincidence with the yrast SD band in {sup 194}Hg reveals the same features as found in the quasicontinuum structure in {sup 192}Hg. These features include: statistical {gamma}rays feeding the SD band, a pronounced E2 peak from transitions feeding the SD band, a Ml/E2 bump at low energies that is associated with the last stages of feeding of the superdeformed band, and a quasicontinuous distribution from {gamma}rays linking SD and normal states, including a sizable clustering of strength around 1.7 MeV. The remarkable similarity of the spectra coincident with SD bands in {sup 192,194}Hg provides additional support for a statistical process for decay out of the SD states. This similarity contrasts with differences observed in the spectrum coincident with the SD band in the odd-even {sup 191}Hg, confirming the predictions about the role of pairing (in normal states) in influencing the shape of the decay-out spectrum.

Comparison between the harris and ab expressions for the description of nuclear superdeformed rotational bands

International Nuclear Information System (INIS)

Hu Zuoxian; Zeng Jinyan

1998-01-01

The superdeformed rotational bands in the A ≅3D 190 region are systematically analyzed using the Harris two-parameter formula and the ab expression, respectively. Similar to the situations in normally deformed nuclei, there exist obvious and systematic deviation of Harris formula from the experiments. In contrast, the prediction of ab formula is very close to experiments, and can be conveniently used for the description of nuclear superdeformed bands

Inter-band coincidences in the superdeformed well of {sup 190}Hg from gammasphere

Energy Technology Data Exchange (ETDEWEB)

Crowell, B.; Carpenter, M.P.; Janssens, R.V.F. [and others

1995-08-01

Very few experimental observables are ordinarily accessible for superdeformed (SD) states in the A {approximately} 150 and A {approximately} 190 regions. The gamma-decay out of the superdeformed bands usually proceeds directly to the normally deformed states, through highly fragmented pathways, making it difficult to determine the spins, parities and excitation energies of the SD states. The in-band E2 transitions are so collective (2 x 10{sup 3} single-particle units in the A {approximately} 190 region) that it is typically impossible to detect any of the competing M1 and E1 transitions between states in the SD well.

Higher superdeformed band members in {sup 190}Hg. Evidence for a band interaction

Energy Technology Data Exchange (ETDEWEB)

Bearden, I G; Daly, P J [Purdue Univ., Lafayette, IN (United States); Janssens, V F; Carpenter, M P; Ahmad, I; Khoo, T L; Lauritsen, T; Liang, Y [Argonne National Lab., IL (United States); Drigert, M W [Idaho National Engineering Lab., Idaho Falls, ID (United States); Garg, U; Reviol, W [Notre Dame Univ., IN (United States); Wyss, R [Joint Inst. for Heavy Ion Research, Oak Ridge, TN (United States)

1992-08-01

The superdeformed band of {sup 190}Hg has been traced up to a frequency {Dirac_h}{omega} {>=} 0.4 MeV by combining data from several experiments. A distinct change in the slope of the dynamic moment of inertia J{sup (2)} vs {Dirac_h}{omega} is observed at {Dirac_h}{omega} 0.32 MeV. This result is interpreted as evidence for a band interaction at the highest frequencies. Possible interpretations are reviewed. (author) 14 refs., 3 figs.

Predicting superdeformed rotational band-head spin in A ∼ 190 ...

Indian Academy of Sciences (India)

PACS No. 21.60.−n. 1. Introduction. Superdeformed (SD) nuclei are one of the most challenging and ... like A ∼ 60, 80, 130, 150 and 190 [2,3]. ..... work and the research is progressing to give systematic features of rotational bands of SD.

Systematic description of superdeformed bands in the mass-190 region

Energy Technology Data Exchange (ETDEWEB)

Sun, Yang; Guidry, M. [Oak Ridge National Lab., TN (United States)]|[Univ. of Tennessee, Knoxville, TN (United States); Zhang, Jing-ye [Univ. of Tennessee, Knoxville, TN (United States)

1996-12-31

Superdeformed bands for the mass-190 region are described by the Projected Shell Model. Even-even, odd mass and odd-odd nuclei are equally well described. Good agreement with available data for all isotopes studied is obtained. The authors calculation of electromagnetic properties and pairing correlations provides an understanding of the observed gradual increase of dynamical moments of inertia with angular momentum observed in many bands in this mass region.

Accurate calculation of superdeformed bands in Hg and Pb

International Nuclear Information System (INIS)

Lei Yian; Zeng Jinyan

1993-01-01

The superdeformed (SD) rotational bands in Hg and Pb are analyzed by means of the abc expression for rotational bands, which was derived from the Bohr Hamiltonian. The agreement between calculated and observed transition energies is incredibly well. The deviation of the calculated E' γ s from the observed results turns out to be absolute value δ ≤0.5 keV (except for a few cases, 0.5 kev ≤ absolute value δ ≤ 0.7 keV). Some transitions which have not been observed yet in these SD bands are also predicted, which may be useful for experimental investigation

Study of the superdeformed band in {sup 194}Pb with EUROGAM

Energy Technology Data Exchange (ETDEWEB)

Hannachi, F [Daresbury Lab. (United Kingdom); [Paris-11 Univ., 91 - Orsay (France). Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse; Porquet, M G; Bastin, G; Deloncle, I; Gall, B; Schuck, C; Smith, A G [Paris-11 Univ., 91 - Orsay (France). Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse; Bourgeois, C; Duprat, J; Korichi, A; Perrin, N; Sergolle, H [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Poffe, N [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; [Oxford Univ. (United Kingdom). Dept. of Physics; Astier, A; Coz, Y Le; Meyer, M; Redon, N [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; Bentley, M; Simpson, J [Daresbury Lab. (United Kingdom); Sharpey-Schafer, J F; Joyce, M J; Beausang, C W; Fallon, P; Paul, E S; Dagnall, P J; Forbes, S A; Gale, S; Jones, P M [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Wadsworth, R; Clark, R M [Bordeaux-1 Univ., 33 - Gradignan (France). Centre d` Etudes Nucleaires; Curien, D [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires

1992-08-01

An experiment has been carried out using a subset of the EUROGAM array to investigate the decay out of the superdeformed (SD) band in {sup 194}Pb. Two new band members and a new decay pattern into the low lying states at normal deformation (ND) have been established for this band. New spectroscopic information about the level scheme at normal deformation has also been extracted. (author). 9 refs., 1 tab., 4 figs.

RDDS lifetime measurements of low-lying superdeformed states in {sup 194}Hg

Energy Technology Data Exchange (ETDEWEB)

Kuehn, R.; Dewald, A.; Kruecken, R. [Universitaet Koeln (Germany)] [and others

1996-12-31

The lifetimes of three low-lying states in the superdeformed (SD) yrast band of {sup 194}Hg were measured by the recoil-distance Doppler-shift method. The deduced transition quadrupole moments, Q{sub t}, equal those extracted from a DSAM measurement for the high-lying states of the band corroborate the assumption that the decay out of SD bands does not strongly affect the structure of the corresponding states. By a simple mixing-model the decay can be described assuming a very small admixture of normal-deformed (ND) states to the decaying SD states. The deduced ND mixing amplitudes for the yrast SD bands in {sup 192,194}Hg and {sup 194}Pb are presented along with average transition quadrupole moments for the lower parts of the excited SD bands.

16O+16O molecular nature of the superdeformed band of 32S and the evolution of the molecular structure

International Nuclear Information System (INIS)

Kimura, Masaaki; Horiuchi, Hisashi

2004-01-01

The relation between the superdeformed band of 32 S and 16 O+ 16 O molecular bands is studied by the deformed-basis antisymmetrized molecular dynamics with the Gogny D1S force. It is found that the obtained superdeformed band members of S have a considerable amount of the 16 O+ 16 O component. Above the superdeformed band, we have obtained two excited rotational bands which have more prominent character of the 16 O+ 16 O molecular band. These three rotational bands are regarded as a series of 16 O+ 16 O molecular bands which were predicted by using the unique 16 O- 16 O optical potential. As the excitation energy and principal quantum number of the relative motion increase, the 16 O+ 16 O cluster structure becomes more prominent but at the same time, the band members are fragmented into several states

Entrance channel dependence in the population of the superdeformed bands in {sup 191}Hg and a model for the feeding mechanism

Energy Technology Data Exchange (ETDEWEB)

Lauritsen, T; Soramel, F; Khoo, T L; Janssens, R V.F.; Ahmad, I; Carpenter, M P; Liang, Y [Argonne National Lab., IL (United States); Fornal, B; Bearden, I; Benet, Ph; Daley, P; Grabowski, Z W; Maier, R [Purdue Univ., Lafayette, IN (United States); Ye, D; Garg, U; Reviol, W [Notre Dame Univ., IN (United States); Drigert, M W [Idaho National Engineering Lab., Idaho Falls, ID (United States)

1992-08-01

The population of the superdeformed bands in {sup 191} Hg has been measured for two reactions with different mass asymmetry. No entrance channel effect was observed, in contrast to similar measurements in the A=150 region. To further elucidate this problem, the entry distribution for the superdeformed band in {sup 192}Hg was measured and a monte Carlo model for the feeding was developed. The simulations suggest that the decision on trapping in the superdeformed well is made at the barrier between the normal and superdeformed wells rather than at the entry point. (author). 9 refs., 3 figs.

Microscopic properties of superdeformed nuclei

Energy Technology Data Exchange (ETDEWEB)

Karlsson, Lennart B

1999-04-01

Many high spin rotational bands in superdeformed nuclei have been found in the A 140 - 150 region, but so far no linking transitions to known normal-deformed states have been found in these nuclei. Therefore, configuration and spin assignments have to be based on indirect spectroscopic information. Identical bands were first discovered in this region of superdeformed states. At present, some identical bands have also been found at normal deformation, but such bands are more common at superdeformation. Recently lifetime measurements have given relative quadrupole moments with high accuracy. Spectroscopic quantities are calculated using the configuration constrained cranked Nilsson-Strutinsky model with the modified oscillator potential. In a statistical study the occurrence of identical bands is tested. Comparing superdeformed and normal deformed nuclei, the higher possibility for identical bands at superdeformation is understood from calculated reduced widths of the E{sub {gamma}} and J{sup (2)} distributions. The importance of high-N orbitals for identical bands is also discussed. Additivity of electric quadrupole moment contributions in the superdeformed A - 150 region is discussed with the nucleus {sup 152}Dy as a `core`. In analytic harmonic oscillator calculations, the effective electric quadrupole moment q{sub eff}, i.e. the change in the total quadrupole moment caused by the added particle, is expressed as a simple function of the single-particle mass, quadrupole moment q{sub {nu}}. Also in realistic calculations, simple relations between q{sub eff} and q{sub {nu}} can be used to estimate the total electric quadrupole moment, e.g. for the nucleus {sup 142}Sm, by adding the effect of 10 holes, to the total electric quadrupole moment of {sup 152}Dy. Furthermore, tools are given for estimating the quadrupole moment for possible configurations in the superdeformed A - 150 region. For the superdeformed region around {sup 143}Eu, configuration and spin assignments

New features of superdeformed bands in 194Hg

International Nuclear Information System (INIS)

Janssens, R.V.F.; Ahmad, I.; Carpenter, M.P.

1995-01-01

A striking difference between superdeformed (SD) nuclei near A = 190 and those in the other regions is the behavior of the dynamic moment of inertia (lm) with the rotational frequency hω. While the (lm) patterns of the SD bands near A = 130 and A = 150 show pronounced variations, the majority of the SD bands near A = 190 display the same large, smooth increase of (lm) within the frequency range 0.15 194 Hg were populated with the reaction 150 Nd( 48 Ca,4n) 194 Hg at a beam energy of 206 MeV. The gamma rays emitted in the reaction were detected with the Gammasphere detector array (32 detectors for this experiment)

Lifetimes of an excited superdeformed band in {sup 192}Hg

Energy Technology Data Exchange (ETDEWEB)

Ahmad, I.; Blumenthal, D.; Carpenter, M.P. [and others

1995-08-01

An excited superdeformed band was identified in {sup 192}Hg and the lifetimes of its levels measured with the Doppler-shift attenuation method from data taken with the Eurogam spectrometer. The band is proposed to be based on the two-quasineutron (v[642]3/2 [512]5/2) configuration, which after a band crossing, becomes the (v[642]3/2 [752]5/2) configuration. The transition quadrupole moment Q{sub t} of the excited band is the same as that of the yrast SD band, within experimental errors. This suggests that the deformation of the SD minimum is robust with respect to quasiparticle excitation, despite the occupation of the deformation-driving v[752]5/2 level (from the j{sub 15/2} shell) after the band crossing.

Predicting superdeformed rotational band-head spin in A ∼ 190 mass region using variable moment of inertia model

International Nuclear Information System (INIS)

Uma, V.S.; Goel, Alpana; Yadav, Archana; Jain, A.K.

2016-01-01

The band-head spin (I 0 ) of superdeformed (SD) rotational bands in A ∼ 190 mass region is predicted using the variable moment of inertia (VMI) model for 66 SD rotational bands. The superdeformed rotational bands exhibited considerably good rotational property and rigid behaviour. The transition energies were dependent on the prescribed band-head spins. The ratio of transition energies over spin Eγ/ 2 I (RTEOS) vs. angular momentum (I) have confirmed the rigid behaviour, provided the band-head spin value is assigned correctly. There is a good agreement between the calculated and the observed transition energies. This method gives a very comprehensive interpretation for spin assignment of SD rotational bands which could help in designing future experiments for SD bands. (author)

Spin assignment and behavior of superdeformed bands in A∼150 mass region

International Nuclear Information System (INIS)

Khalaf, A.; Sirag, M.; Taha, M.

2012-01-01

The smoothed experimental dynamical moment of inertia J (2) values were fitted with a theoretical version depend on Harris three parameter formula in even power of angular frequency ω, derived for results from cranking model. The expansion parameters were adjusted by using a computer simulated search program. The best expansion parameters from the fit were used to assign the spins of the superdeformed ( SD ) rotational bands (RB ) by integrating the calculated J (2) . The data set include 23 RB's in 11 SD nuclei, which show no evidence of either irregular behavior near the bottom of the bands or abrupt angular momentum at low rotational frequency in the mass region ranging from A= 142 to A = 154. we used the differences of angular momenta at constant frequency as effective alignment. The relative properties of superdeformed rotational bands (SDRB's) are analyzed in terms of the effective alignment of the valence nucleons. The effective alignment is a powerful tool to assign the configurations, to select the identical bands as well as to predict new SD bands from other combination of the orbitals. The ΔI = 2 energy staggering observed in 3 of our selected SDRB's are also described from a smooth reference representing the finite difference approximation to the fourth derivative of the γ-ray transition energies.

Observation of superdeformation in 191Hg

International Nuclear Information System (INIS)

Moore, E.F.; Janssens, R.V.F.; Chasman, R.R.

1989-01-01

The first observation of superdeformation in the A ≅ 190 mass region is reported. A rotational band of 12 transitions with an average energy spacing of 37 keV, an average moment of inertia of 110 ℎ 2 MeV -1 , and an average quadrupole moment of 18 ± 3 eb has been observed in 191 Hg. These results are in excellent agreement with a calculation that predicts an ellipsoidal axis ratio of 1.65:1 for the superdeformed shape in this nucleus. Evidence for another discrete superdeformed band and superdeformed structures in the quasi-continuum was also found in the data. 19 refs., 6 figs

Superfluid to normal phase transition and extreme regularity od superdeformed bands

CERN Document Server

Pavlichenkov, I M

2002-01-01

The exact semiclassical expression for the second inertial parameter B for the superfluid and normal phases is derived. Interpolation between these limiting values shows that the function B(I) changes sign at the spin I sub c , which is critical for a rotational spectrum. The quantity B turns out to be a sensitive measure of the change in static pairing correlations. The superfluid-to-normal transition reveals itself in the specific variation of the ratio B/A versus spin I with the plateau characteristic of the normal phase. This dependence is find to be universal for normal deformed and superdeformed nuclei. The long plateau with a small value B/A approx A sup - sup 8 sup / sup 3 explains the extreme regularity of superdeformed bands

Superdeformations and fermion dynamical symmetries

International Nuclear Information System (INIS)

Wu, Cheng-Li

1990-01-01

In this talk, I will present a link between nuclear collective motions and their underlying fermion dynamical symmetries. In particular, I will focus on the microscopic understanding of deformations. It is shown that the SU 3 of the one major shell fermion dynamical symmetry model (FDSM) is responsible for the physics of low and high spins in normal deformation. For the recently observed phenomena of superdeformation, the physics of the problem dictates a generalization to a supershell structure (SFDSM), which also has an SU 3 fermion dynamical symmetry. Many recently discovered feature of superdeformation are found to be inherent in such an SU 3 symmetry. In both cases the dynamical Pauli effect plays a vital role. A particularly noteworthy discovery from this model is that the superdeformed ground band is not the usual unaligned band but the D-pair aligned (DPA) band, which sharply crosses the excited bands. The existence of such DPA band is a key point to understand many properties of superdeformation. Our studies also poses new experimental challenge. This is particularly interesting since there are now plans to build new and exciting γ-ray detecting systems, like the GAMMASPHERE, which could provide answers to some of these challenges. 34 refs., 11 figs., 5 tabs

Search for excited superdeformed bands in {sup 151}Dy

Energy Technology Data Exchange (ETDEWEB)

Nisius, D.; Janssens, R.V.F.; Crowell, B. [and others

1995-08-01

Following the first report of superdeformed (SD) bands with identical transition energies in the pairs ({sup 151}Tb*,{sup 152}Dy), ({sup 150}Gd*, {sup 151}Tb) and ({sup 153}Dy*, {sup 152}Dy) (where * denotes an excited SD band), it was proposed by Nazarewicz et al. that the observations could be understood in a strong-coupling approach if pseudo SU(3) symmetry were invoked. In this model there are three limiting values of the decoupling parameter; i.e. a = 0, {plus_minus}1. In the first two cases mentioned above the pairs of bands have nearly identical transition energies and are interpreted as proton excitations involving the [200]1/2 pseudospin orbital coupled to the {sup 152}Dy core, for which the value of the decoupling parameter is calculated to be a =+1.

Decay out of the superdeformed band in {sup 143}Eu

Energy Technology Data Exchange (ETDEWEB)

Atac, A; Piiparinen, M; Herskind, B [Copenhagen Univ. (Denmark); and others

1992-08-01

The connection between the super-deformed (SD) and normal-deformed (ND) states had not been observed, owing its difficulty to a statistical, highly fragmented decay path out of the SD bands. This left both the spin and the excitation energy of the SD bands undetermined. In this paper, the authors present results of a new experimental approach, where they take advantage of triple and higher-fold coincidences to study the decay-out of a SD band. They carried out an experiment at the Niels Bohr Institute Tandem Accelerator Laboratory, where they used the (160 MeV) {sup 37}Cl + {sup 110}Pd {yields} {sup 143}Eu + 4n reaction. 9 refs., 3 figs.

Exotic superdeformed structure in A∼190 nuclei observed using Eurogam2

International Nuclear Information System (INIS)

Wilson, A.N.; Timar, J.; Bergstroem, M.; Paul, E.S.; Bouneau, S.; Azaiez, F.; Korichi, A.; Nakatsukasa, T.

1995-01-01

Dipole transitions between superdeformed rotational bands are only very rarely observed due to the competition from the very strong in-band E2 decays. We have carried out two experiments with the EUROGAM2 γ-ray spectrometer, situated at the Vivitron tandem accelerator at CRN Strasbourg, in September and October 1994. In the first experiment we observe M1 dipole transitions between the signature partner yrast superdeformed bands in 193 Tl. This measurement gives a mean value of (g K -g R ) K/Q o = 0.135 ± 0.010 μ N /eb identifying the bands as belonging to the (642)5/2 single particle orbital. We also observe 5 additional new superdeformed bands in 193 Tl, whose structures are discussed. In the second experiment we observe three transitions, at 911, 865 and 831 keV, which link an excited superdeformed band in 190 Hg to the yrast superdeformed band. The data suggest that these are stretched dipole transitions with E1 multipolarity and strengths of about 10 -3 Wu. This is the first observation of a collective vibration of the superdeformed mean field. We also observe two new superdeformed bands in 190 Hg. (authors). 39 refs., 11 figs., 3 tabs

New results on the superdeformed {sup 196}Pb nucleus: The decay of the excited bands to the yrast band

Energy Technology Data Exchange (ETDEWEB)

Bouneau, S.; Azaiez, F.; Duprat, J. [IPN, Orsay (France)] [and others

1996-12-31

The study of the superdeformed (SD) {sup 196}Pb nucleus has been revisited using the EUROGAM phase 2 spectrometer. In addition to the known yrast and two lowest excited SD bands, a third excited SD band has been seen. All of the three excited bands were found to decay to the yrast SD band through, presumably, E1 transitions, allowing relative spin and excitation energy assignments. Comparisons with calculations using the random-phase approximation suggest that all three excited bands can be interpreted as octupole vibrational structures.

Dynamical moments of inertia for superdeformed nuclei

International Nuclear Information System (INIS)

Obikhod, T.V.

1995-01-01

The method of quantum groups has been applied for calculation the dynamical moments of inertia for the yrast superdeformed bands in 194 Hg and 192 Hg as well as to calculation of the dynamical moments of inertia of superdeformed bands in 150 Gd and 148 Gd

Superdeformed bands of odd nuclei in A=190 region in the quasiparticle picture

International Nuclear Information System (INIS)

Terasaki, J.; Flocard, H.; Heenen, P.H.; Bonche, P.

1996-07-01

Properties of the superdeformed (SD) bands of 195 Pb and 193 Hg have been studied by the cranked Hartree-Fock-Bogoliubov method. The calculations reproduce the flat behavior of the dynamical moment of inertia of two of the SD bands of 195 Pb measured recently. Possible configuration assignments for the observed bands 3 and 4 of 195 Pb are discussed. The two interacting SD bands of 193 Hg have also been calculated. The analysis confirms the superiority of a density-dependent pairing force over a seniority pairing interaction. (author)

Properties of superdeformed bands in the 151Tb nucleus studied with the EUROGAM French-British spectrometer

International Nuclear Information System (INIS)

Finck, Christian

1997-01-01

The subject of this thesis is the study of superdeformation (SD) of the atomic nucleus. In the mass region A ≅ 150 those nuclei have a quadrupole deformation of about 0.6. However, this value is an average and the microscopic structure reflected in the band configurations, affects this deformation. Determination of this value by electric quadrupole moment studies is particularly useful especially for the identical SD bands (SD bands belonging to neighbouring nuclei and having the same moment of inertia). Knowledge of the different quadrupole deformation should shed light on the competition between mass difference, spin alignment and deformation of the nucleus. The electric quadrupole moments are deduced from lifetime measurements of the SD states using the Doppler Shift Attenuation Method. Experimentally, one observes a variation in the electric quadrupole moments of the lowest SD states which suggests a gradual change of the nuclear deformation towards normal less deformed shapes. The deexcitation mechanism is poorly understood in the A ≅ 150 mass region due to lack of experimental information: up to now, no transition connecting the second and the first potential well has been observed for these SD states. Experimental studies of deexcitation patterns of SD bands are therefore crucial to fix the decay-out mechanism. Experimental data on the 151 Tb nucleus were collected via fusion-evaporation reaction, using the EUROGAM phase II array. (author)

Description of identical superdeformed bands of the A ∝ 190 mass region

International Nuclear Information System (INIS)

Dadwal, Anshul; Mittal, H.M.

2017-01-01

The two-parameter formula/model viz. nuclear softness (NS) formula, semiclassical particle rotor model (PRM) and exponential model with pairing attenuation are used for the reliable phenomenological analysis of identical superdeformed bands. These formulae/models are employed to study the identical superdeformed bands of the A ∝ 190 mass region, {"1"9"1Hg(2), "1"9"3Hg(2)}, {"1"9"1Hg(3), "1"9"3Hg(3)}, {"1"9"3Tl(3), "1"9"3Tl(5)}, {"1"9"3Tl(1), "1"9"4Tl(3)}, {"1"9"3Tl(1), "1"9"4Tl(4)}, {"1"9"3Pb(3), "1"9"1Hg(2)}, {"1"9"3Pb(4), "1"9"1Hg(3)}, {"1"9"4Pb(1), "1"9"2Hg(1)}, {"1"9"4Pb(1), "1"9"4Hg(1)} and middle-point identical bands {"1"9"3Tl(1), "1"9"3Tl(2)}, {"1"9"3Tl(1), "1"9"5Tl(1)} and {"1"9"3Tl(2), "1"9"5Tl(2)}. Quantitatively, good results of γ-ray transitions energies and dynamic moment of inertia are obtained using the NS formula. The parameters, band-head moment of inertia (I_0), alignment (i) and effective pairing parameter (Δ_0) are calculated using the least-squares fitting of the γ-ray transitions energies in the NS formula, semiclassical PRM and exponential model with pairing attenuation, respectively. The calculated parameters are found to depend sensitively on the proposed band-head spin. (orig.)

Description of identical superdeformed bands of the A ∝ 190 mass region

Energy Technology Data Exchange (ETDEWEB)

Dadwal, Anshul; Mittal, H.M. [Dr. B.R. Ambedkar National Institute of Technology, Jalandhar (India)

2017-06-15

The two-parameter formula/model viz. nuclear softness (NS) formula, semiclassical particle rotor model (PRM) and exponential model with pairing attenuation are used for the reliable phenomenological analysis of identical superdeformed bands. These formulae/models are employed to study the identical superdeformed bands of the A ∝ 190 mass region, {"1"9"1Hg(2), "1"9"3Hg(2)}, {"1"9"1Hg(3), "1"9"3Hg(3)}, {"1"9"3Tl(3), "1"9"3Tl(5)}, {"1"9"3Tl(1), "1"9"4Tl(3)}, {"1"9"3Tl(1), "1"9"4Tl(4)}, {"1"9"3Pb(3), "1"9"1Hg(2)}, {"1"9"3Pb(4), "1"9"1Hg(3)}, {"1"9"4Pb(1), "1"9"2Hg(1)}, {"1"9"4Pb(1), "1"9"4Hg(1)} and middle-point identical bands {"1"9"3Tl(1), "1"9"3Tl(2)}, {"1"9"3Tl(1), "1"9"5Tl(1)} and {"1"9"3Tl(2), "1"9"5Tl(2)}. Quantitatively, good results of γ-ray transitions energies and dynamic moment of inertia are obtained using the NS formula. The parameters, band-head moment of inertia (I{sub 0}), alignment (i) and effective pairing parameter (Δ{sub 0}) are calculated using the least-squares fitting of the γ-ray transitions energies in the NS formula, semiclassical PRM and exponential model with pairing attenuation, respectively. The calculated parameters are found to depend sensitively on the proposed band-head spin. (orig.)

New vistas in superdeformation

Energy Technology Data Exchange (ETDEWEB)

Nazarawicz, W [Joint Inst. for Heavy Ion Research, Oak Ridge, TN (United States)

1992-08-01

Nuclear shape coexistence, or superdeformation, is not a new topic; it dates back to the mid-fifties. In this review, the author concentrates on the following aspects: hyperdeformations, with the Woods-Saxon-Strutinsky total potential energy for thorium-232 as an example; superdeformations far from stability, particularly in mercury isotopes; effective calculation of interactions and effective operators; spin assignments and identical bands. 65 refs., 3 figs.

Band head spin assignment of superdeformed bands in Hg isotopes through power index formula

Science.gov (United States)

Sharma, Honey; Mittal, H. M.

2018-05-01

The power index formula has been used to obtain the band head spin (I 0) of all the superdeformed (SD) bands in Hg isotopes. A least squares fitting approach is used. The root mean square deviations between the determined and the observed transition energies are calculated by extracting the model parameters using the power index formula. Whenever definite spins are available, the determined and the observed transition energies are in accordance with each other. The computed values of dynamic moment of inertia J (2) obtained by using the power index formula and its deviation with the rotational frequency is also studied. Excellent agreement is shown between the calculated and the experimental results for J (2) versus the rotational frequency. Hence, the power index formula works very well for all the SD bands in Hg isotopes expect for 195Hg(2, 3, 4).

Superdeformation in the mass 190 region

International Nuclear Information System (INIS)

Khoo, T.L.; Lauritsen, T.; Liang, Y.

1992-01-01

The steps in the formation of superdeformed bands are described. The hot compound nucleus cools and is trapped within the superdeformed secondary minimum becoming a cold system executing periodic motion (rotation), before suddenly heating up in the process of decaying to the normal yrast states

Superdeformation in /sup 104,105/Pd

International Nuclear Information System (INIS)

Macchiavelli, A.O.; Burde, J.; Diamond, R.M.; Beausang, C.W.; Deleplanque, M.A.; McDonald, R.J.; Stephens, F.S.; Draper, J.E.

1988-01-01

In the present Rapid Communication, we report the discovery of a rotational band in /sup 105/Pd and possibly one in /sup 104/Pd that can be interpreted as arising from superdeformed shapes. The moments of inertia, J/sup (1)/ and J/sup (2)/, of these bands are similar to those measured in the Ce--Nd region, once the A/sup 5/3/ mass dependence is removed. This implies a deformation ε∼0.35--0.4. If so, this is the third mass region where superdeformed bands have been found at high spins

Assignment of Nilsson orbitals at superdeformation - identical bands

Energy Technology Data Exchange (ETDEWEB)

Ragnarsson, I [Lund Univ. (Sweden). Dept. of Mathematical Physics

1992-08-01

The relative transition energies of superdeformed rotational bands are used to extract ``effective alignments`` of the valence particles. It is found that the effective alignments give a direct picture of the Nilsson orbitals which are active in {sup 146-150}Gd, i.e., especially the orbitals [651 1/2] and [642 5/2], and that all bands observed in these nuclei can be understood within one consistent scheme. The experimental features are reproduced in calculations using the Nilsson-Strutinsky cranking model. The nearly identical transition energies seen in neighboring odd-proton and even-proton nuclei in the Dy/Tb/Gd region are investigated using the same formalism. Again, a consistent picture seems to emerge where, as suggested previously, the nucleus with a hole in the [301 1/2] Nilsson orbital and the corresponding core nucleus have calculated transition energies which are almost identical over a large range in spin. 2 refs., figs.

Multi-particle excitations in the superdeformed {sup 149}Gd nucleus

Energy Technology Data Exchange (ETDEWEB)

Flibotte, S. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires]|[Department of Physics and Astronomy, McMaster, University, Hamilton ON L8S 4M1 (Canada)]|[AECL Research, Chalk River Laboratories, Chalk River ON K0J 1J0 (Canada); Hackman, G. [Department of Physics and Astronomy, McMaster, University, Hamilton ON L8S 4M1 (Canada); Ragnarsson, I. [Department of Mathematical Physics, Lund institute of Technology, Box 118 S-221, Lund (Sweden); Theisen, C. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Andrews, H.R. [AECL Research, Chalk River Laboratories, Chalk River ON K0J 1J0 (Canada); Ball, G.C. [AECL Research, Chalk River Laboratories, Chalk River ON K0J 1J0 (Canada); Beausang, C.W. [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 3BX (United Kingdom); Beck, F.A. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Belier, G. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Bentley, M.A. [Staffordshire University, Stoke on Trent (United Kingdom); Byrski, T. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Curien, D. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; France, G. de [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Disdier, D. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Duchene, G. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Haas, B. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Haslip, D.S. [Department of Physics and Astronomy, McMaster, University, Hamilton ON L8S 4M1 (Canada); Janzen, V.P. [Department of Physics and Astronomy, McMaster, University, Hamilton ON L8S 4M1 (Canada)]|[AECL Research, Chalk River Laboratories, Chalk River ON K0J 1J0 (Canada); Jones, P.M. [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 3BX (United Kingdom); Kharraja, B.

1995-02-20

Six rotational bands built on superdeformed intrinsic configurations have been observed in the {sup 149}Gd nucleus with the Eurogam spectrometer. Orbital configuration assignments have been suggested on the basis of their effective alignments calculated with the Nilsson-Strutinsky cranking model. Most of the excited bands have identical partners in neighboring nuclei including one case differing by four mass units. Measurements of feeding patterns indicate that the {sup 149}Gd yrast superdeformed band is fed over a wider range of angular momentum than other yrast superdeformed bands in this mass region whereas weaker excited bands in the same nucleus are populated in narrower spin windows. ((orig.))

Superdeformation in the Hg-Tl-Pb region

International Nuclear Information System (INIS)

Henry, E.A.; Becker, J.A.; Yates, S.W.; Wang, T.F.; Kuhnert, A.; Brinkman, M.J.; Cizewski, J.A.; Deleplanque, M.A.; Diamond, R.M.; Stephens, F.S.; Azaiez, F.; Korten, W.; Draper, J.E.

1990-10-01

Superdeformation in the Hg-Tl-Pb region is discussed, with concentration on the experimental results. At least twenty-five superdeformed bands are known in this region, providing much new data to test theoretical calculations. 22 refs., 5 figs

ΔI=4 bifurcation in a superdeformed band: Evidence for a C4 symmetry

International Nuclear Information System (INIS)

Flibotte, S.; Andrews, H.R.; Ball, G.C.; Beausang, C.W.; Beck, F.A.; Belier, G.; Byrski, T.; Curien, D.; Dagnall, P.J.; de France, G.; Disdier, D.; Duchene, G.; Finck, C.; Haas, B.; Hackman, G.; Haslip, D.S.; Janzen, V.P.; Kharraja, B.; Lisle, J.C.; Merdinger, J.C.; Mullins, S.M.; Nazarewicz, W.; Radford, D.C.; Rauch, V.; Savajols, H.; Styczen, J.; Theisen, C.; Twin, P.J.; Vivien, J.P.; Waddington, J.C.; Ward, D.; Zuber, K.; Aberg, S.

1993-01-01

The moment of inertia of the yrast superdeformed band in 149 Gd exhibits an unexpected bifurcation at high rotational frequency. States differing by four units of angular momentum show an energy shift of about 60 eV. This indicates the remnant of a new quantum number associated with the fourfold rotational symmetry

Search for the discrete non-yrast states in 152Dy around 86 ns isomer, the region into which the γ-rays drain the super-deformed band

International Nuclear Information System (INIS)

Mansour, N.

1991-01-01

Further analysis of the γ-ray study of 152 Dy emitted in the decay of the super-deformed band has been performed by using the 122 Sn ( 35 Cl, P4n) reaction at low bombarding energies. Several γ-rays de-exciting non-yrast states have been identified, among these are transitions previously observed in coincidence with this super-deformed band. The lowest two members of the super-deformed cascade have also been detected, but the data is not quite good enough to make a firm connection to them. (author)

Backbendings of superdeformed bands in 36;40Ar

Science.gov (United States)

Xiang, Xu-Hui; He, Xiao-Tao

2018-05-01

Experimentally observed superdeformed (SD) rotational bands in 36Ar and 40Ar are studied by the cranked shell model (CSM) with the pairing correlations treated by a particle-number-conserving (PNC) method. This is the first time that PNC-CSM calculations have been performed on the light nuclear mass region around A=40. The experimental kinematic moments of inertia J (1) versus rotational frequency are reproduced well. The backbending of the SD band at frequency around ℏω=1.5 MeV in 36Ar is attributed to the sharp rise of the simultaneous alignments of the neutron and proton 1d 5/2[202]5/2 pairs and 1f 7/2[321]3/2 pairs, which is a consequence of the band crossing between the 1d 5/2[202]5/2 and 1f 7/2[321]3/2 configuration states. The gentle upbending at low frequency of the SD band in 40Ar is mainly affected by the alignments of the neutron 1f 7/2[321]3/2 pairs and proton 1d 5/2[202]5/2 pairs. The PNC-CSM calculations show that besides the diagonal parts, the off-diagonal parts of the alignments play an important role in the rotational behavior of the SD bands. Supported by National Natural Science Foundation of China (11775112 and 11275098) and the Priority Academic Program Development of Jiangsu Higher Education Institutions

X-ray yields of superdeformed states in 193Hg

International Nuclear Information System (INIS)

Cullen, D.M.; Lee, I.Y.; Baktash, C.

1993-01-01

The K α =x-ray yields associated with the superdeformed and normal-deformed bands in 193 Hg have been measured. The results indicate an excess yield of K α -x rays in coincidence with the superdeformed cascade relative to that in coincidence with the normal-deformed cascade. The internal conversion of known transitions along the superdeformed cascade cannot account for the observed K α -x ray yield. It is likely that this excess x-ray yield is associated with low energy M1 transitions competing with the low-spin superdeformed E2 transitions. These M1 γ rays are expected to connect the two superdeformed bands which are observed in coincidence with each other. Calculations based on the measured γ-ray intensities indicate that within the experimental uncertainties the excess K α yield can be entirely accounted for by interband-M1 transitions. X-ray yields from the recent 193 Hg EUROGAM experiment will also be discussed

Entrance channel effects and the superdeformed band in {sup 152}Dy

Energy Technology Data Exchange (ETDEWEB)

Beausang, C W; Alderson, A; Ali, I; Dagnall, P J; Fallon, P; Forsyth, P D; Smith, G; Twin, P J [Liverpool Univ. (United Kingdom); France, G de; Duchene, G; Flibotte, S; Haas, B; Romain, P; Theisen, C H; Vivien, J P [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Bentley, M A [Daresbury Lab. (United Kingdom)

1992-08-01

Recent experiments on {sup 152}Dy indicate that the fraction of decays via the superdeformed (SD) band depends on the mass asymmetry in the entrance channel. Such results may indicate that the time scale for fusion is larger for mass symmetric reactions than for mass asymmetric ones, thus allowing neutron evaporation to compete better with fusion. To test this idea, one needs accurate intensity measurements of the highest member of the SD band, using a very large data set, so it is an ideal experiment for the Eurogam array. At the time of the conference, a series of experiments was being carried out using the {sup 36}S + {sup 120}Sn and {sup 82}Se + {sup 74}Ge reactions. Preliminary results were inconclusive. 7 refs., 3 figs.

Vortex excitations and identical superdeformed bands

Energy Technology Data Exchange (ETDEWEB)

Waddington, J C; Bhaduri, R K [McMaster Univ., Hamilton, ON (Canada). Dept. of Physics

1992-08-01

Striking relationships exist amongst the transition energies of the identical superdeformed bands (SDB). In this paper, the authors suggest that all of these bands in both the mass 150 and mass 190 regions can be explained as excitations of the specially stable doubly closed shell {sup 152}Dy. Typical of these bands is the case of {sup 153}Dy. Two excited SDB`s were observe which not only have a moment of inertia identical to that of {sup 152}Dy, but the transition energies are shifted by exactly {+-}1/4 of a rotational spacing. It is as though the spin 1/2 of the last neutron had been added directly to the angular momentum of the core, but the mass of this last particle had not contributed to the moment of inertia. The possibility is being investigated that the identical SDBs arise from an equivalent picture under the strong rotation of the specially stable {sup 152}Dy. The rotation renders the 3-dimensional space topologically nontrivial. The moment of inertia of {sup 192}Hg extrapolated to zero spin is identical to that of {sup 152}Dy at high spin. This suggests that a superfluid is formed as particles are added to {sup 152}Dy to make {sup 192}Hg. It is proposed that as the rotational frequency of {sup 192}Hg is increased, quantized vortices are formed, like vortices in superfluid {sup 4}He. These vortices lead to an additional alignment in{sup 192}Hg relative to the {sup 152} core, increasing as I{sup 2}, reaching a value of 4{Dirac_h} at I = 48. 3 refs., 3 figs.

Superdeformation in the mass A ∼ 80 region

International Nuclear Information System (INIS)

Baktash, C.

1996-01-01

A new island of superdeformed nuclei with major-to-minor axis ratio of 2:1 has recently been discovered in the A ∼ 80 medium-mass region, confirming the predictions for the existence of a large SD gap at particle number N,Z ∼ 44. The general properties of more than 20 bands observed so far will be reviewed here, and compared with those of the superdeformed bands in the heavier nuclei

Quasiparticle excitations in superdeformed {sup 192}Hg

Energy Technology Data Exchange (ETDEWEB)

Lauritsen, T.; Carpenter, M.P.; Janssens, R.V.F. [and others

1995-08-01

The nucleus {sup 192}Hg plays a pivotal role for superdeformation in the mass 190 region, since calculations of single-particle levels show large shell-gaps for the superdeformed (SD) shape at N = 112 and Z = 80. As a result, {sup 192}Hg is referred to as the doubly magic SD nucleus for the A = 190 region. In previous studies, only one superdeformed band was observed in this nucleus, and this fact was cited as indirect evidence that large shell gaps do indeed exist at the proposed particle numbers.

Coexistence of spherical states with deformed and superdeformed bands in doubly magic 40Ca; A shell model challenge

International Nuclear Information System (INIS)

Caurier, E.; Nowacki, F.; Menendez, J.; Poves, A.

2007-02-01

Large scale shell model calculations, with dimensions reaching 10 9 , are carried out to describe the recently observed deformed (ND) and superdeformed (SD) bands based on the first and second excited 0 + states of 40 Ca at 3.35 MeV and 5.21 MeV respectively. A valence space comprising two major oscillator shells, sd and pf, can accommodate most of the relevant degrees of freedom of this problem. The ND band is dominated by configurations with four particles promoted to the pf-shell (4p-4h in short). The SD band by 8p-8h configurations. The ground state of 40 Ca is strongly correlated, but the closed shell still amounts to 65%. The energies of the bands are very well reproduced by the calculations. The out-band transitions connecting the SD band with other states are very small and depend on the details of the mixing among the different np-nh configurations, in spite of that, the calculation describes them reasonably. For the in-band transition probabilities along the SD band, we predict a fairly constant transition quadrupole moment Q 0 (t) ∼ 70 e fm 2 up to J=10, that decreases toward the higher spins. We submit also that the J=8 states of the deformed and superdeformed band are maximally mixed. (authors)

Coexistence of spherical states with deformed and superdeformed bands in doubly magic 40Ca: A shell-model challenge

International Nuclear Information System (INIS)

Caurier, E.; Nowacki, F.; Menendez, J.; Poves, A.

2007-01-01

Large-scale shell-model calculations, with dimensions reaching 10 9 , are carried out to describe the recently observed deformed (ND) and superdeformed (SD) bands based on the first and second excited 0 + states of 40 Ca at 3.35 and 5.21 MeV, respectively. A valence space comprising two major oscillator shells, sd and pf, can accommodate most of the relevant degrees of freedom of this problem. The ND band is dominated by configurations with four particles promoted to the pf shell (4p-4h in short). The SD band by 8p-8h configurations. The ground state of 40 Ca is strongly correlated, but the closed shell still amounts to 65%. The energies of the bands are very well reproduced by the calculations. The out-band transitions connecting the SD band with other states are very small and depend on the details of the mixing among the different np-nh configurations; in spite of that, the calculation describes them reasonably. For the in-band transition probabilities along the SD band, we predict a fairly constant transition quadrupole moment Q 0 (t)∼170 e fm 2 up to J=10 that decreases toward the higher spins. We submit also that the J=8 states of the deformed and superdeformed bands are maximally mixed

Superdeformation in the A=150 and A=190 regions

International Nuclear Information System (INIS)

Carpenter, M. P.

1998-01-01

Superdeformation has been established for over a decade in the mass 150 region and nearly as long in the A=190 region. The first measurements directed at nuclei in these regions concentrated on mapping out the superdeformed (SD) islands by identifying SD rotational bands in γ-ray coincidence data. These early studies provided new insights into the physics of superdeformation, but also raised unexpected issues. The new gamma-ray arrays (Gammasphere, Eurogam/Euroball and Gasp) have provided a wealth of new data on properties of SD states in these two mass regions. This paper highlights some of the more recent results from the large arrays which have addressed the outstanding issues in the field, namely, ΔI = 4 staggering, identical bands, SD vibrational bands, and questions about the feeding into and the decay out of the SD well

Superdeformation in the A=150 and A=190 regions.

Energy Technology Data Exchange (ETDEWEB)

Carpenter, M. P.

1998-12-01

Superdeformation has been established for over a decade in the mass 150 region and nearly as long in the A=190 region. The first measurements directed at nuclei in these regions concentrated on mapping out the superdeformed (SD) islands by identifying SD rotational bands in {gamma}-ray coincidence data. These early studies provided new insights into the physics of superdeformation, but also raised unexpected issues. The new gamma-ray arrays (Gammasphere, Eurogam/Euroball and Gasp) have provided a wealth of new data on properties of SD states in these two mass regions. This paper highlights some of the more recent results from the large arrays which have addressed the outstanding issues in the field, namely, {Delta}I = 4 staggering, identical bands, SD vibrational bands, and questions about the feeding into and the decay out of the SD well.

Search for superdeformation in 144Gd

International Nuclear Information System (INIS)

Vivien, J.P.; Nourreddine, A.; Beck, F.A.; Byrski, T.; Gehringer, C.; Haas, B.; Merdinger, J.C.; Dudek, J.; Nazarewicz, W.

1986-01-01

Quasi-continuum γ-decay studies of 144 Gd have been performed using the 120 Sn( 28 Si,4n)reaction at 125, 135, 145 and 155 MeV bombarding energies. Angular distribution and multiplicity measurements have been done at the above energies. At 145 MeV bombarding energy a lifetime measurement has also been performed. Although a collective behaviour has been observed, the present data do not give evidence for population of superdeformed rotational bands. Theoretical interpretation using the cranking model with the Woods-Saxon field is given. The effects of temperature and pairing on the superdeformed configuration are discussed; superdeformation effects are predicted to disappear below I ∼ 60-70 ℎ when temperature exceeds ∼ 500 KeV

Superdeformation in the A=150 and A=190 regions

International Nuclear Information System (INIS)

Carpenter, M. P.; Janssens, R. V. F.

1999-01-01

Superdeformation has been established for over a decade in the mass 150 region and nearly as long in the A=190 region. The first measurements directed at nuclei in these regions concentrated on mapping out the superdeformed (SD) islands by identifying SD rotational bands in γ-ray coincidence data. These early studies provided new insights into the physics of superdeformation, but also raised unexpected issues. The new gamma-ray arrays (Gammasphere, Eurogam/Euroball and Gasp) have provided a wealth of new data on properties of SD states in these two mass regions. This paper highlights some of the more recent results from the large arrays which have addressed the outstanding issues in the field, namely, ΔI=4 staggering, identical bands, SD vibrational bands, and questions about the feeding into and the decay out of the SD well. (c) 1999 American Institute of Physics

The quasi-continuum of gamma rays following the decay of superdeformed bands in the Hg region

Energy Technology Data Exchange (ETDEWEB)

Lauritsen, T.; Khoo, T.L.; Janssens, R.V.F. [Argonne National Lab., IL (United States)] [and others

1996-12-31

The quasi-continuum part of the spectrum associated with the decay-out of the yrast superdeformed band in {sup 194}Hg has been extracted. It has for the first time been possible to compare the spin and excitation energy determined from the analysis of the quasi-continuum {gamma} rays to the exact result obtained from the one-step linking transitions.

Description of superdeformed nuclear states in the interacting boson model

International Nuclear Information System (INIS)

Liu, Y.; Zhao, E.; Liu, Y.; Song, J.; Liu, Y.; Sun, H.; Zhao, E.; Liu, Y.; Sun, H.

1997-01-01

We show in this paper that the superdeformed nuclear states can be described with a four parameter formula in the spirit of the perturbated SU(3) limit of the sdg IBM. The E2 transition γ-ray energies, the dynamical moments of inertia of the lowest superdeformed (SD) bands in even-even Hg, Pb, Gd, and Dy isotopes, and the energy differences ΔE γ -ΔE γ ref of the SD band 1 of 194 Hg are calculated. The calculated results agree with experimental data well. This indicates that the SD states are governed by a rotational interaction plus a perturbation with SO sdg (5) symmetry. The perturbation causing the ΔI=4 bifurcation to emerge in the ΔI=2 superdeformed rotational band may then possess SO sdg (5) symmetry. copyright 1997 The American Physical Society

Lifetime measurements and dipole transition rates for superdeformed states in 190Hg

International Nuclear Information System (INIS)

Amro, H.

1999-01-01

The Doppler-shift attenuation method was used to measure life-times of superdeformed (SD) states for both the yrast and the first excited superdeformed band of 190 Hg. Intrinsic quadruple moments Q 0 were extracted. For the first time, the dipole transition rates have been extracted for the inter-band transitions which connect the excited SD band to the yrast states in the second minimum. The results support the interpretation of the excited SD band as a rotational band built on an octupole vibration

Superdeformation studies in {sup 191}Hg

Energy Technology Data Exchange (ETDEWEB)

Carpenter, M.P.; Janssens, R.V.F.; Crowell, B. [and others

1995-08-01

Superdeformation in the A {approximately} 190 region was first observed in {sup 191}Hg from an experiment performed at ATLAS using the Argonne Notre Dame {gamma}-ray facility. We recently revisited the study of superdeformation in this nucleus using Gammasphere and the {sup 160}Gd({sup 36}S,5n) and {sup 174}Yb({sup 22}Ne,5n) reactions at 172 and 120 MeV in order to populate and measure states in the second well. The goal of the experiment was to identify new bands in the data, and thus allow us to gain understanding on the relative placement of single particle orbitals near the N = 112 SD shell gap. From an analysis of the data, the three previously identified SD bands were extended, and their feeding into the yrast states delineated. Two new SD bands were observed and preliminary evidence for a third new band was obtained as well.

Superdeformation studies in the odd-odd nucleus {sup 192}Tl

Energy Technology Data Exchange (ETDEWEB)

Fischer, S.; Carpenter, M.P.; Janssens, R.V.F. [and others

1995-08-01

The study of yrast and near-yrast structures of odd-odd nuclei to high spins is somewhat limited due to the complexity of the spectra resulting from the many proton-neutron couplings near the Fermi surface. In superdeformed nuclei, the number of available protons and neutrons near the Fermi surface is somewhat limited due to the presence of large-shell gaps which stabilize the nuclear shape. A relatively small number of available neutron and proton configurations can lead to fragmentation of the SD intensity into a number of different bands. Two good examples of this phenomenon were found in {sup 192}Tl and {sup 194}Tl where the presence of six superdeformed bands were reported in both nuclei. We reexamined {sup 192}Tl at Gammasphere using the {sup 160}Gd({sup 37}Cl,5n) reaction at 178 MeV to populate states in the superdeformed well of this nucleus. While our previous study on {sup 192}Tl at ATLAS was very successful, a number of questions remained which formed the basis of our objectives in this experiment: obtain better {gamma}-ray energies for the known transitions and identify higher spin members in each band; determine how the bands feed the known yrast states in {sup 192}Tl as well as determine the complete spectrum in coincidence with the SD bands; look for M1 transitions connecting proposed signature partners; and attempt to identify other excitations in the superdeformed well. Analysis is underway and four of the six bands were confirmed. The reasons that two of the reported bands were not observed in this latest work is still under investigation. As of this time, no other superdeformed bands were identified in the data. Two of the confirmed SD bands have a constant moment of inertia and show indications of cross-talk between each other. This observation is not unexpected since the calculated M1 rates for the proposed configuration of the band, {pi}{sub 13/2} x {upsilon}j{sub 15/2}, indicate that M1 transitions linking the two SD bands should be observed.

Favored neutron excitations in superdeformed Gd-147

NARCIS (Netherlands)

Theisen, C; Khadiri, N; Vivien, JP; Ragnarsson, J; Beausang, CW; Beck, FA; Belier, G; Byrski, T; Curien, D; deFrance, G; Disdier, D; Duchene, G; Finck, C; Flibotte, S; Gall, B; Haas, B; Hanine, H; Herskind, B; Kharraja, B; Merdinger, JC; Nourreddine, A; Nyako, BM; Perez, GE; Prevost, D; Stezowski, O; Rauch, I; Rigollet, C; Savajols, H; SharpeySchafer, J; Twin, PJ; Wei, L; Zuber, K

1996-01-01

Four new superdeformed (SD) bands have been observed in Gd-147 using the EUROGAM II spectrometer. By comparison with (146,148,149),Gd SD bands, we use the effective alignment to assign excited band configurations, with the support of the Nilsson-Strutinsky cranking formalism. The effect of the

M1 transitions between superdeformed states in 195Tl

International Nuclear Information System (INIS)

Zheng Xing; Xingqu Chen; Xiaochun Wang

1996-01-01

Using a triaxial-particle-rotor model, the quadrupole and dipole transition energies, kinematic and dynamic moments of inertia, electromagnetic transition probabilities and the relative intensity of the E2 γ-transitions are calculated for superdeformed bands in 195 Tl. A strong perturbation effect of rotation on transition energies and M1 and E2 transitions of superdeformed states is investigated. The total M1 transitions, enhanced by internal conversion, are expected to compete strongly with the E2 γ-ray at low spins in the superdeformed 195 Tl nucleus. (author)

Double blocking in the superdeformed {sup 192}Tl nucleus

Energy Technology Data Exchange (ETDEWEB)

Liang, Y; Carpenter, M P; Janssens, R V.F.; Ahmad, I; Henry, R; Khoo, T L; Lauritsen, T [Argonne National Lab., IL (United States); Soramel, F [Padova University, Padova (Italy); Pilotte, S [Ottawa Univ., ON (Canada); Lewis, J M; Riedinger, L L; Yu, C H [Tennessee Univ., Knoxville, TN (United States); Garg, U; Reviol, W [Notre Dame Univ., IN (United States); Bearden, I G [Purdue Univ., Lafayette, IN (United States)

1992-08-01

Six superdeformed bands have been found in the nucleus {sup 192}Tl. For two of the bands, the dynamic moment of inertia J{sup (2)} is found to be constant with the rotational frequency {Dirac_h}{omega}. This result can be understood in terms of Pauli blocking of quasiparticle alignments in intruder orbitals, and represents the first experimental evidence that the alignment of these intruders is responsible for the smooth rise in J{sup (2)} seen in other superdeformed nuclei of this mass region. (author). 18 refs., 2 figs.

Lifetime measurements and dipole transition rates for superdeformed states in {sup 190}Hg.

Energy Technology Data Exchange (ETDEWEB)

Amro, H.

1999-03-24

The Doppler-shift attenuation method was used to measure life-times of superdeformed (SD) states for both the yrast and the first excited superdeformed band of {sup 190}Hg. Intrinsic quadruple moments Q{sub 0} were extracted. For the first time, the dipole transition rates have been extracted for the inter-band transitions which connect the excited SD band to the yrast states in the second minimum. The results support the interpretation of the excited SD band as a rotational band built on an octupole vibration.

Search for two-{gamma} sum-energy peaks in the decay out of superdeformed bands

Energy Technology Data Exchange (ETDEWEB)

Blumenthal, D.; Khoo, T.L.; Lauritsen, T. [and others

1995-08-01

The spectrum of {gamma}rays decaying out of the superdeformed (SD) band in {sup 192}Hg has a quasicontinuous distribution. Whereas methods to construct level schemes from discrete lines in coincidence spectra are well established, new techniques must still be developed to extract information from coincidences involving quasicontinuous {gamma}rays. From an experiment using Eurogam, we obtained impressively clean 1- and 2-dimensional {gamma} spectra from pairwise or single gates, respectively, on the transitions of the SD band in {sup 192}Hg. We investigated methods to exploit the 2-dimensional quasicontinuum spectra coincident with the SD band to determine the excitation energy of the SD band above the normal yrast line. No strong peaks were observed in the 2-{gamma} sum spectra; only candidates of peaks at a 2-3 {sigma} level were found. This suggests that 2-{gamma} decay is not the dominant decay branch out of SD bands, consistent with the observed multiplicity of 3.2. We shall next search for peaks in sum-spectra of 3 {gamma}s.

The decay-out of superdeformed bands in the A = 190 region. What have we learned?

International Nuclear Information System (INIS)

Lauritsen, T.; Hackman, G.; Khoo, T.L.; Carpenter, M.P.; Janssens, R.V.F.; Ackermann, D.; Ahmad, I.; Blumenthal, D.J.; Lopez-Martens, A.

1997-01-01

One-step decay transitions linking the superdeformed (SD) bands 1 and 3 in 194 Hg to yrast levels are discussed. Inter-band transitions between bands 1 and 3 have also been identified. For the first time, the spin, parity and excitation energy have been determined for two SD bands in the same nucleus. The low excitation energy of the excited band supports the view that it is based on an octupole excitation. It is believed that Porter-Thomas fluctuations play a major role in determining the strength of the one-step transitions as suggested by the fact that only one other SD band has been linked in the A = 190 mass region ( 194 Pb) at the present time. When Porter-Thomas fluctuations prevent the observation of one-step or two-step linking transitions, as e.g. in the case of 192 Hg, the analysis of the quasi-continuous part of the decay-out spectrum provides an alternative method for the determination of the excitation energy and spin of an SD band. This method is discussed in detail. (author)

Study of the superdeformed states of the gadolinium nuclei: neutron excitations in {sup 147}Gd nucleus; Etude des etats superdeformes de noyaux de Gadolinium: Excitations neutron dans le noyau {sup 147}Gd

Energy Technology Data Exchange (ETDEWEB)

Khadiri, Najia [Institut de Recherche Subatomique, CNRS-IN2P3 - Universite Louis Pasteur, 67 - Strasbourg (France)

1997-10-17

This work is devoted to nuclear structure studies of superdeformed states in the second potential well. Under focus are the gadolinium isotopes and in particular the {sup 147}Gd nucleus. High spin states in {sup 147}Gd have been populating by {sup 122}Sn ({sup 30}Si,5n){sup 147}Gd fusion-evaporation reaction with a silicon beam of 158 MeV delivered by the VIVITRON accelerator of the Institut de Recherches Subatomiques. The nucleus {gamma} de-excitations have been measured using the EUROGAM II {gamma}-ray multidetector. On the basis of multiple coincidences, four new superdeformed (SD) rotational bands have been assigned to {sup 147}Gd nucleus. Nuclear structures corresponding to these bands have been investigated by shell model calculations using a harmonic oscillator potential with cranking, in the Nilsson Strutinsky formalism. Comparison of dynamical moments of inertia of band (1) and (5) in {sup 147}Gd with {sup 148}Gd(2) and {sup 146}Gd(1) SD bands has fixed the role of the [651 1/2]{alpha} = -1/2 orbital crossing frequency. Theoretical calculations reproduce quite well the {sup 148}Gd(2), {sup 127}Gd(1,5) and G{sup 146}Gd(1) dynamical moments of inertia. Using the particle hole excitation nature of {sup 149,148,147,146}Gd bands, effective spin alignment of [651 1/2]{alpha}= {+-}1/2, [770 1/2]{alpha} = -1/2 and [441 1/2]{alpha} = +1/2 orbitals have been deduced from the experiment in agreement with the theoretical values. Of particular interest, the spin alignment measured for the [441 1/2]{alpha} +1/2 orbital, with a value close to zero, is in contradiction with the value predicted by the Pseudo SU(3) model, formalism often used to explain the identical band phenomenon. (author) 68 refs., 41 figs., 17 tabs.

Coexistence of cluster structure and superdeformation in 44Ti

International Nuclear Information System (INIS)

Kimura, Masaaki; Horiuchi, Hisashi

2006-01-01

The nucleus 44 Ti has low-lying levels of various kinds of mutually very different nuclear structure displaying the richness of the nuclear many-body dynamics. It is shown that the deformed-basis antisymmetrized molecular dynamics by the use of the Gogny D1S force reproduces successfully and unifiedly two types of coexistence phenomena in 44 Ti. Namely, on one hand, the coexistence of the mean-field structure and the cluster structure is confirmed by verifying the normally deformed structure of the K π =3 1 - band with a 1-particle-1-hole intrinsic configuration and the α+Ca40 cluster structure of the K π =0 2 - band. The mixed character of the mean-field-like structure and the α+Ca40 cluster structure of the ground band is also shown. On the other hand, the coexistence of the normal deformed mean-field and the superdeformed mean-field is confirmed by verifying the triaxial superdeformation of the K π =0 2 + band and the K π =2 1 + band which has a 4-particle-4-hole intrinsic configuration. Good reproduction of the experimental data is shown for many kinds of quantities including the energy spectra, electric transition rates, alpha spectroscopic factors. Preliminary discussions are given on the existence of hyperdeformed excited states, the relation between superdeformation and clustering and so on

Superdeformed bands in Hg and Tl nuclei for N≤112

International Nuclear Information System (INIS)

Carpenter, M.P.; Jannsens, R.V.F.; Liang, Y.; Ahmad, I.; Henry, R.; Khoo, T.L.; Lauritsen, T.; Soramel, F.; Lewis, J.M.; Riedinger, L.L.; Yu, C.H.; Garg, U.; Reviol, W.; Pilotte, S.; Bearden, I.G.; Daly, P.J.

1992-01-01

The study of superdeformed (SD) nuclei in the A ∼ 190 region has provided a wealth of new information on SD states at moderate to high spins (I ∼ 10 to 50 h). The dynamical moment of inertia for almost all of the SD bands reported on to date in this mass region display a similar behavior, i.e. a smooth increase with increasing rotational frequency. This increase has been attributed to both quasiparticle alignments and a decrease in pairing with increasing rotational frequency. However, standard mean-field calculations have problems reproducing the magnitude and extent of the rise. The authors' recent results on SD states in the Hg-Tl nuclei at and below the N = 112 SD-gap add support to this interpretation of the rise in the dynamical moment of inertia while at the same time showing more clearly the inadequacies of the previous theoretical calculations

Synthetical analysis of the spin assignment for the superdeformed bands in A≅190 region

International Nuclear Information System (INIS)

Di Yaomin

2002-01-01

The spin assignment for the superdeformed bands of even-even nuclei in A ≅190 region is given by means of using the method of synthetical analysis. The I( I + 1) expression is used to fit the experimental data of the transition γ energies. In contrast to other procedure, the convergence process of the series expansions is put stress upon, whereas taking how many terms exactly in the expression does not emphasized. Moreover as well as the method of fitting the physical quantity, by use of these series expansions the moment of inertia of band heads is also calculated and then the systematics is used for the spin assignments. In practice, when the experimental data is abundant the systematics of the moment of inertia of band heads is more efficient than the method of fitting the physical quantity in the spin assignment. As for a few bands which spin assignment is difficult, the deviation from the typical rotational bands must be considered, which may be judged easily from the second class of moment of inertia of the bands. Finally the results of the spin assignment and the comparison with other literature are presented. These results should be more reliable

Determination of the bandheads spin and investigation of identical bands for Even - A nuclei of the superdeformed mass region 190

International Nuclear Information System (INIS)

Shalaby, A.S.

2005-01-01

Using the three-parameter expression of harris expansion of the rotational energy, the dynamical moment of inertia is represented by a power-series expansion in even powers of the rotational frequency. The three expansion coefficients were determined by using Marquardt method of nonlinear least-squares routines, to fit the proposed dynamical moment of inertia with its recent experimental data for the superdeformed (SD) nuclei in the A 190 mass region. The calculated dynamical moment of inertia with the best parameters is then integrated to obtain the spin, which in turn was used to determine the static moment of inertia. The comparison of the dynamic moment of inertia and spin with their available experimental data shows good agreements between them. These procedures were succeedingly done for nine superdeformed bands in the A 190 nuclei: 1 90Hg(B1, B3), 1 94PB(B1, B2, B3), 1 96PB(B1, B2, B3), 1 94PB(B1, B22, B3), 1 96BP((B1, B2, B3) and 1 98PO. We have also investigated the identity exist among these SD bands. It was shown that some of these SD bands are identical to each other

Superdeformation in {sup 191}Tl

Energy Technology Data Exchange (ETDEWEB)

Pilotte, S; Lewis, J M; Riedinger, L L; Yu, C H [Tennessee Univ., Knoxville, TN (United States). Dept. of Physics; Capenter, M P; Janssens, R V.F.; Khoo, T L; Lauritsen, T; Liang, Y; Soramel, F [Argonne National Lab., IL (United States). Physics Div.; Bearden, I G [Purdue Univ., Lafayette, IN (United States)

1992-08-01

High spin states in {sup 191}T1 have been populated via the {sup 159}Tb({sup 36}S,4n) reaction at 165 MeV. Two weak sequences of regularly spaced transitions have been identified. These bands exhibit many of the properties observed in many other superdeformed nuclei in the Hg region. (author). 23 refs., 5 figs.

Evidence for octupole softness of the superdeformed shape from band interactions in sup 193,4 Hg

Energy Technology Data Exchange (ETDEWEB)

Cullen, D.M.; Riley, M.A.; Alderson, A.; Ali, I.; Fallon, P.; Forsyth, P.D.; Hanna, F.; Mullins, S.M.; Roberts, J.W.; Sharpey-Schafer, J.F.; Twin, P.J. (Liverpool Univ. (UK). Oliver Lodge Lab.); Bengtsson, T. (Lund Inst. of Tech. (Sweden). Dept. of Mathematical Physics); Bentley, M.A.; Bruce, A.M.; Simpson, J. (Science and Engineering Research Council, Daresbury (UK). Daresbury Lab.); Nazarewicz, W. (Liverpool Univ. (UK). Oliver Lodge Lab. Politechnika Warszawska (Poland). Inst. Fizyki); Poynter, R.; Regan, P.; Wadsworth, R. (York Univ. (UK). Dept. of Physics); Satula, W. (Warsaw Univ. (Poland). Inst. Fizyki Teoretycznej); Sletten, G. (Niels Bohr Inst., Roskilde (Denmark). Tandem Accelerator Lab.); Wyss, R. (Manne Siegbahn Inst. of Physics, Stockholm (Sweden))

1990-12-24

Three superdeformed (SD) bands have been observed in {sup 194}Hg and four (or five ) SD bands in {sup 193}Hg using the {sup 150}Nd+{sup 48}Ca reaction. All bands except for two in {sup 193}Hg show a steady increase in dynamical moment of inertia J{sup (2)} with rotational frequency. The two exceptional bands form a classical pair of strongly interacting bands. It is suggested that the strong interaction between the bands is caused by a softness to octupole deformation. Evidence is found for the existence of dipole transitions connecting bands of opposite signature in {sup 193}Hg. The strengths of these transitions suggest that they are probably E1 supporting the importance of the role of octupole vibrations. These data suggest the wider importance of octupole softness in enhancing E1 transitions in the SD feeding and decay mechanisms. The spectroscopy of the observed SD bands in {sup 193,4}Hg are discussed in detail and attention is drawn to the 'identical' energies of {gamma}-rays in these isotopes with those in lighter isotopes. The similarities in bands relate to the neutron sub-shell closure for SD nuclei at N=112. (orig.).

Triaxial superdeformation in 40Ar

International Nuclear Information System (INIS)

Taniguchi, Yasutaka; Ikeda, Kiyomi; Kanada-En'yo, Yoshiko; Kimura, Masaaki; Horiuchi, Hisashi; Ideguchi, Eiji

2010-01-01

Superdeformed (SD) states in 40 Ar have been studied using the deformed-basis antisymmetrized molecular dynamics. Low-energy states were calculated by the parity and angular momentum projection and the generator coordinate method (GCM). Basis wave functions were obtained by the energy variation with a constraint on the quadrupole deformation parameter β, while other quantities such as triaxiality γ were optimized by the energy variation. By the GCM calculation, an SD band was obtained just above the ground-state band. The SD band involves a K π =2 + side band due to the triaxiality. The calculated electric quadrupole transition strengths of the SD band reproduce the experimental values appropriately. Triaxiality is significant for understanding low-lying states.

Coexistence of cluster structure and superdeformation in {sup 44}Ti

Energy Technology Data Exchange (ETDEWEB)

Kimura, Masaaki [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)]. E-mail: masaaki@yukawa.kyoto-u.ac.jp; Horiuchi, Hisashi [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)

2006-03-06

The nucleus {sup 44}Ti has low-lying levels of various kinds of mutually very different nuclear structure displaying the richness of the nuclear many-body dynamics. It is shown that the deformed-basis antisymmetrized molecular dynamics by the use of the Gogny D1S force reproduces successfully and unifiedly two types of coexistence phenomena in {sup 44}Ti. Namely, on one hand, the coexistence of the mean-field structure and the cluster structure is confirmed by verifying the normally deformed structure of the K{sup {pi}}=3{sub 1}{sup -} band with a 1-particle-1-hole intrinsic configuration and the {alpha}+Ca40 cluster structure of the K{sup {pi}}=0{sub 2}{sup -} band. The mixed character of the mean-field-like structure and the {alpha}+Ca40 cluster structure of the ground band is also shown. On the other hand, the coexistence of the normal deformed mean-field and the superdeformed mean-field is confirmed by verifying the triaxial superdeformation of the K{sup {pi}}=0{sub 2}{sup +} band and the K{sup {pi}}=2{sub 1}{sup +} band which has a 4-particle-4-hole intrinsic configuration. Good reproduction of the experimental data is shown for many kinds of quantities including the energy spectra, electric transition rates, alpha spectroscopic factors. Preliminary discussions are given on the existence of hyperdeformed excited states, the relation between superdeformation and clustering and so on.

Projected shell model description of N = 114 superdeformed isotone nuclei

International Nuclear Information System (INIS)

Guo, R S; Chen, L M; Chou, C H

2006-01-01

A systematic description of the yrast superdeformed (SD) bands in N 114, Z = 80-84 isotone nuclei using the projected shell model is presented. The calculated γ-ray energies, moment of inertia and M1 transitions are compared with the data for which spin is assigned. Excellent agreement with the available data for all isotones is obtained. The calculated electromagnetic properties provide a microscopic understanding of those measured nuclei. Some predictions in superdeformed nuclei are also discussed

Microscopic descriptions of the superdeformed bands in the region A 190: Bohr and Routhian Hamiltonians in the Hartree-Fock-Bogolyubov approximation

International Nuclear Information System (INIS)

Libert, J.; Girod, M.; Delaroche, J-P.; Berger, J-F.; Romain, P.; Peru, S.

1997-01-01

The superdeformed bands of the nuclei in the region A = 190 were described by two microscopic approaches using Gogny D1 finite range interaction. The first one consists in building a Bohr Hamiltonian in the framework of Gauss overlap approximation (GOA) of the generator-coordinate method, starting from Hartree-Fock-Bogolyubov solutions under quadrupole constraints. This collective Hamiltonian microscopically determined for five quadrupolar variables is then diagonalized by a projection method on a collective based adapted to the large variety of the deformations to be considered. A special attention was given to the precise definition of the under-barrier collective wavefunctions (for which an original method of solving the collective Schroedinger equation was developed) in order to described correctly the lifetime of the shape isomeric states. The other approach, that of Routhian is based also on the Hartree-Fock-Bogolyubov approximation. The calculations are carried out with and without restoring the broken symmetry associated to the particle numbers (as given by Lipkin-Nogami). The results (excitation energies, moments of inertia, etc...) of the two calculation methods are compared with most recent experimental data. The existence of the superdeformed bands corresponding to vibrational excitations similar to those appearing in β and γ bands is proposed

Properties of superdeformed bands in the {sup 151}Tb nucleus studied with the EUROGAM French-British spectrometer; Proprietes des bandes superdeformees dans le noyau de {sup 151}Tb etudiees avec le spectrometre franco-britannique EUROGAM

Energy Technology Data Exchange (ETDEWEB)

Finck, Christian [Centre de Recherches Nucleaires de Strasbourg-Cronenbourg, 67 (France)

1997-04-24

The subject of this thesis is the study of superdeformation (SD) of the atomic nucleus. In the mass region A {approx_equal} 150 those nuclei have a quadrupole deformation of about 0.6. However, this value is an average and the microscopic structure reflected in the band configurations, affects this deformation. Determination of this value by electric quadrupole moment studies is particularly useful especially for the identical SD bands (SD bands belonging to neighbouring nuclei and having the same moment of inertia). Knowledge of the different quadrupole deformation should shed light on the competition between mass difference, spin alignment and deformation of the nucleus. The electric quadrupole moments are deduced from lifetime measurements of the SD states using the Doppler Shift Attenuation Method. Experimentally, one observes a variation in the electric quadrupole moments of the lowest SD states which suggests a gradual change of the nuclear deformation towards normal less deformed shapes. The deexcitation mechanism is poorly understood in the A {approx_equal} 150 mass region due to lack of experimental information: up to now, no transition connecting the second and the first potential well has been observed for these SD states. Experimental studies of deexcitation patterns of SD bands are therefore crucial to fix the decay-out mechanism. Experimental data on the {sup 151}Tb nucleus were collected via fusion-evaporation reaction, using the EUROGAM phase II array. (author) 121 refs., 61 figs., 22 tabs.

16O + 16O + valence neutrons in molecular orbitals structures of positive- and negative-parity superdeformed bands in 34S

International Nuclear Information System (INIS)

Taniguchi, Yasutaka

2015-01-01

The structures of superdeformed (SD) states in 34 S have been investigated using the antisymmetrized molecular dynamics and generator coordinate method (GCM). The GCM basis wave functions are calculated via energy variation with a constraint on the quadrupole deformation parameter β. By applying the GCM after parity and angular momentum projections, the coexistence of two positive- and one negative-parity SD bands are predicted, and low-lying states and other deformed bands are obtained. The SD bands have structures of 16 O + 16 O + two valence neutrons in molecular orbitals around the two 16 O cores in a cluster picture. The configurations of the two valence neutrons are δ 2 and π 2 for the positive-parity SD bands and π 1 δ 1 for the negative-parity SD band. (author)

16O + 16O + valence neutrons in molecular orbitals structures of positive- and negative-parity superdeformed bands in 34S

International Nuclear Information System (INIS)

Taniguchi, Yasutaka

2014-01-01

The structures of superdeformed (SD) states in 34 S are investigated using the antisymmetrized molecular dynamics and generator coordinate method (GCM). The GCM basis wave functions are calculated via energy variation with a constraint on the quadrupole deformation parameter β. By applying the GCM after parity and angular momentum projections, the coexistence of two positive- and one negative-parity SD bands are predicted, and low-lying states and other deformed bands are obtained. The SD bands have structures of 16 O + 16 O + two valence neutrons in molecular orbitals around the two 16 O cores in a cluster picture. The configurations of the two valence neutrons are δ 2 and π 2 for the positive-parity SD bands and π 1 δ 1 for the negative-parity SD band

Favored neutron excitations in superdeformed 147Gd

International Nuclear Information System (INIS)

Theisen, C.; Khadiri, N.; Vivien, J.P.; Ragnarsson, I.; Beausang, C.W.; Beck, F.A.; Belier, G.; Byrski, T.; Curien, D.; de France, G.; Disdier, D.; Duchene, G.; Finck, C.; Flibotte, S.; Gall, B.; Haas, B.; Hanine, H.; Herskind, B.; Kharraja, B.; Merdinger, J.C.; Nourreddine, A.; Nyako, B.M.; Perez, G.E.; Prevost, D.; Stezowski, O.; Rauch, V.; Rigollet, C.; Savajols, H.; Sharpey-Schafer, J.; Twin, P.J.; Wei, L.; Zuber, K.

1996-01-01

Four new superdeformed (SD) bands have been observed in 147 Gd using the EUROGAM II spectrometer. By comparison with 146,148,149 Gd SD bands, we use the effective alignment to assign excited band configurations, with the support of the Nilsson-Strutinsky cranking formalism. The effect of the crossing of the [642]5/2 and [651]1/2 neutron orbitals lying just below the magic N=86 SD shell gap has been investigated for the 146,147,148 Gd bands. Evidence for the [411]1/2 orbital is also given. copyright 1996 The American Physical Society

Search for entrance-channel dependence in the population of superdeformed bands in {sup 191}Hg

Energy Technology Data Exchange (ETDEWEB)

Soramel, F.; Khoo, T.L.; Janssens, R.V.F. [and others

1995-08-01

The population intensity of some SD bands in the mass 150 region were observed to depend on the mass symmetry of the entrance channel in the fusion reaction. The authors raised the possibility that the population of SD bands had a memory of the entrance channel. To check this interesting possibility, we made measurements of the population intensities of superdeformed (SD) bands in the {sup 160}Gd({sup 36}S,5n){sup 191}Hg and {sup 130}Te({sup 64}Ni,3n){sup 191}Hg reactions. To ensure that any observed effect was not due to a simple angular momentum difference in the entrance channels, we also measured the average entry points and spin distributions of normal and SD states in {sup 191}Hg in the two reactions. The entry points and spin distributions for {sup 191}Hg are the same and, indeed, so are the SD intensities in the two reactions. Hence, no entrance-channel effect is observed in the population of the SD band in {sup 191}Hg, in contrast with data for SD bands in the mass 150 regions. We suggest that the effect observed previously in the mass 150 region is due to an angular momentum effect. A letter reporting our results was submitted for publication.

Superdeformed and high-spin nuclear structure data on the INTERNET

International Nuclear Information System (INIS)

Singh, B.; Firestone, R.B.; Chu, S.Y.F.

1997-01-01

With the advent of the large detector arrays GAMMASPHERE, EUROGAM, and GASP, a wealth of new information about the properties of nuclei at high spin has become available. Superdeformed and high-spin nuclear structure data and associated bibliographic information made available on INTERNET by the Isotopes Project at LBNL are described. The Table of Superdeformed Bands and Fission Isomers on the INTERNET will be updated continuously, and new recent reference lists will be provided approximately every three months. This information will also be published annually in the Table of Isotopes CD-ROM updates. (author)

Feeding and decay of superdeformed states

International Nuclear Information System (INIS)

Khoo, T.L.; Lauritsen, T.; Ahmad, I.; Carpenter, M.P.; Fernandez, P.B.; Janssens, R.V.F.; Moore, E.F.; Wolfs, F.L.H.; Benet, Ph.; Daly, P.J.; Beard, K.B.; Garg, U.; Ye, D.; Drigert, M.W.

1992-01-01

The mechanisms for feeding and decay of superdeformed (SD) bands are examined. Data connected with both processes in 192 Hg are compared with model calculations. The calculations successfully reproduce the data, suggesting that the mechanisms for both processes are understood. Constraints on the energy of the SD band energies and on the well-depths at low and high spins have been obtained. At the point of decay around spin 10, we suggest that the SD band is 3.3--4.3 MeV above the normal yrast line and that the well depths at spin 10 and 40 are 0.5--1.3 and 3.5--4.5 MeV, respectively

Excitation Energies of Superdeformed States in 196Pb: Towards a Systematic Study of the Second Well in Pb Isotopes

International Nuclear Information System (INIS)

Wilson, A.N.; Singh, A.K.; Huebel, H.; Rossbach, D.; Schonwasser, G.; Davidson, P.M.; Dracoulis, G.D.; Lane, G.J.; Goergen, A.; Korichi, A.; Hannachi, F.; Lopez-Martens, A.; Astier, A.; Azaiez, F.; Bourgeois, C.; Bazzacco, D.; Kroell, T.; Rossi-Alvarez, C.; Buforn, N.; Redon, N.

2005-01-01

The excitation energy of the lowest-energy superdeformed band in 196 Pb is established using the techniques of time-correlated γ-ray spectroscopy. Together with previous measurements on 192 Pb and 194 Pb, this result allows superdeformed excitation energies, binding energies, and two-proton and two-neutron separation energies to be studied systematically, providing stringent tests for current nuclear models. The results are examined for evidence of a 'superdeformed shell gap'

A comparative study of superdeformation in 146,147,148Gd. Possible manifestations of the pseudo-SU3 symmetry, octupole shape susceptibility and superdeformed deep-hole excitations

International Nuclear Information System (INIS)

Zuber, K.; Balouka, D.; Beck, F.A.; Byrski, T.; Curien, D.; France, G. de; Duchene, G.; Gehringer, C.; Haas, B.; Merdinger, J.C.; Romain, P.; Santos, D.; Styczen, J.; Vivien, J.P.; Dudek, J.; Szymanski, Z.; Werner, T.R.

1991-01-01

Two discrete superdeformed (SD) bands have been identified in the nucleus 147 Gd and the twin-band mechanism studied by comparison with SD results for 146,148 Gd. Theoretical interprettion in terms of nucleonic orbitals with the Woods-Saxon potential is consistent with the pseudo-spin symmetry picture and the octupole susceptibility mechanism predicted by theory. (orig.)

Detailed spectroscopy in the superdeformed second minimum of 240Pu

International Nuclear Information System (INIS)

Thirolf, P.G.; Gassmann, D.; Habs, D.; Chromik, M.J.; Eisermann, Y.; Graw, G.; Hertenberger, R.; Maier, H.J.; Metz, A.; Reiter, P.

2000-01-01

Complete text of publication follows. Superdeformed prolate nuclei, having an axis ratio of about 2:1, have first been discovered in fission isomers in the actinide region almost 40 years ago by Polikanov et al.. Their interpretation of being the result of microscopic shell corrections on top of the macroscopic liquid drop potential leading to a second minimum in the nuclear potential energy surface is well established. 240 Pu with its 3.7 ns fission isomer may be regarded as the prototype nucleus for spectroscopic studies of superdeformed actinide nuclei since the identification of the ground state rotational band in conversion electron measurements [1]. Though from the knowledge on excited states in the first minimum and previous measurements in the second minimum low-lying collective excitations in the second minimum low-lying collective excitations in the second well of 240 Pu can be expected, none of them has been experimentally identified so far. Quite surprisingly, no low-lying collective quadrupole excitations could be observed in a recent detailed high-resolution and high-efficiency γ-spectroscopy experiment [2]. Complementary information could be obtained in conversion electron measurements in coincidence with isomeric fission performed at the Garching Accelerator Laboratory, resulting in the first identification of the lowest β-vibrational band [3]. In a combined analysis of the γ-spectroscopic and conversion electron data conversion coefficients α K or limits on α K could be deduced, thus allowing to determine the multipolarities of the transitions. A predominant population of negative parity states in the second well could be observed that can be explained by the filtering function of the inner and outer fission barrier. Complementary transmission resonance measurements have been performed, yielding new information on the fine structure of (β-)vibrational multi-phonon states. A new method could be established to determine the excitation energy of

Nuclear superdeformation

International Nuclear Information System (INIS)

Nazarewicz, W.; Tennessee Univ., Knoxville, TN

1992-01-01

In the year 1986 new types of exotic states, the so-called superdeformed states, were discovered in fast rotating heavy atomic nuclei. They are characterized by an unusually large distortion (comparable to that appearing in fissioning isomers) and occur at high angular momenta. A sizeable amount of high-spin data on superdeformed states makes it possible, for the first time, to test many fine details of the shell structure at very large elongations and very high angular momentum

Proton configurations and pairing correlations at the N=80 superdeformed shell closure: Study of 145Tb

International Nuclear Information System (INIS)

Mullins, S.M.; Schmeing, N.C.; Flibotte, S.; Hackman, G.; Rodriguez, J.L.; Waddington, J.C.; Yao, L.; Andrews, H.R.; Galindo-Uribarri, A.; Janzen, V.P.; Radford, D.C.; Ward, D.; DeGraaf, J.; Drake, T.E.; Pilotte, S.; Paul, E.S.

1994-01-01

A superdeformed band has been observed in the N=80 nucleus 145 Tb which was produced with the reactions 112 Sn( 37 Cl,2p2n) and 118 Sn( 31 P,4n) at bombarding energies of 187 and 160 MeV, respectively. Since superdeformed bands also exist in the three lighter N=80 isotones 142 Sm, 143 Eu, and 144 Gd, it is now possible to understand the valence-proton configurations of these bands in a systematic way. The T (2) dynamic moment of inertia in 145 Tb shows no evidence for the N = 6 quasiproton crossing that is observed in 144 Gd. Comparison with cranked Woods-Saxon and total Routhian surface calculations suggests that the proton configuration in 145 Tb is 6 1 direct-product[404] 9/2 + 2 in which the quasiproton crossing is blocked. Furthermore, like 143 Eu and 142 Sm, there is no evidence in the T (2) for the N=6 quasineutron crossing predicted by the calculations. This may indicate that static neutron pairing correlations are quenched at the N=80 superdeformed shell closure

Octupole correlations in neutron-rich {sup 143,145}Ba and a type of superdeformed band in {sup 145}Ba

Energy Technology Data Exchange (ETDEWEB)

Zhu, S.J.; Wang, M.G.; Long, G.L.; Zhu, L.Y.; Gan, C.Y.; Yang, L.M.; Sakhaee, M.; Li, M.; Deng, J.K. [Physics Department, Tsinghua University, Beijing 100084, Peoples Republic of (China); Zhu, S.J.; Hamilton, J.H.; Ramayya, A.V.; Jones, E.F.; Hwang, J.K.; Zhang, X.Q.; Gore, P.M.; Peker, L.K.; Drafta, G.; Babu, B.R.; Deng, J.K.; Ginter, T.N.; Beyer, C.J.; Kormicki, J.; Ter-Akopian, G.M.; Daniel, A.V. [Physics Department, Vanderbilt University, Nashville, Tennessee 37235 (United States); Zhu, S.J.; Ter-Akopian, G.M.; Daniel, A.V. [Joint Institute for Heavy Ion Research, Oak Ridge, Tennessee 37831 (United States); Ma, W.C. [Physics Department, Mississippi State University, Mississippi 39762 (United States); Cole, J.D.; Aryaeinejad, R.; Drigert, M.W. [Idaho National Engineering Laboratory, Idaho Falls, Idaho 83415 (United States); Rasmussen, J.O.; Asztalos, S.; Lee, I.Y.; Macchiavelli, A.O.; Chu, S.Y.; Gregorich, K.E.; Mohar, M.F. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Ter-Akopian, G.M.; Daniel, A.V.; Oganessian, Y.T.; Kliman, J. [Flerov Laboratory for Nuclear Reactions, Joint Institute for Nuclear Research, Dubna (Russia); Donangelo, R. [Universidade Federal do Rio de Janeiro, Caixa Postal 68528, RG (Brazil); Stoyer, M.A.; Lougheed, R.W.; Moody, K.J.; Wild, J.F. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Prussin, S.G. [Nuclear Engineering Department, University of California at Berkeley, Berkeley, California 94720 (United States); Kliman, J. [Institute of Physics, SASc, Dubravskacesta 9, 84228 Bratislava (Slovakia); Griffin, H.C. [University of Michigan, Ann Arbor, Michigan 48104 (United States)

1999-11-01

High spin states in neutron-rich odd-{ital Z} {sup 143,145}Ba nuclei have been investigated from the study of prompt {gamma} rays in the spontaneous fission of {sup 252}Cf by using {gamma}-{gamma}- and {gamma}-{gamma}-{gamma}- coincidence techniques. Alternating parity bands are identified for the first time in {sup 145}Ba and extended in {sup 143}Ba. A new side band, with equal, constant dynamic, and kinetic moments of inertia equal to the rigid body value, as found in superdeformed bands, is discovered in {sup 145}Ba. Enhanced E1 transitions between the negative- and positive-parity bands in these nuclei give evidence for strong octupole deformation in {sup 143}Ba and in {sup 145}Ba. These collective bands show competition and coexistence between symmetric and asymmetric shapes in {sup 145}Ba. Evidence is found for crossing M1 and E1 transitions between the s=+i and s={minus}i doublets in {sup 143}Ba. {copyright} {ital 1999} {ital The American Physical Society}

Superdeformation- present status and some new universal features

International Nuclear Information System (INIS)

Jain, A.K.; Jain, S.R.

1995-01-01

The present status of understanding of superdeformed (SD) bands has been presented. The puzzles raised by the experimental data have been highlighted. Besides the well known problems related to feeding and depopulation, moment of inertia and identical bands, we have also pointed out the existence of a weak oscillation in the I vs. E γ plots, the negative value for the net alignment in many SD bands and the general identical band pattern found in each mass region. Theoretical explanation for many of these features have been suggested individually but there is no single theoretical framework which would be able to explain all the features together. (author). 32 refs

A comparative study of superdeformation in sup 146,147,148 Gd. Possible manifestations of the pseudo-SU sub 3 symmetry, octupole shape susceptibility and superdeformed deep-hole excitations

Energy Technology Data Exchange (ETDEWEB)

Zuber, K.; Balouka, D.; Beck, F.A.; Byrski, T.; Curien, D.; France, G. de; Duchene, G.; Gehringer, C.; Haas, B.; Merdinger, J.C.; Romain, P.; Santos, D.; Styczen, J.; Vivien, J.P.; Dudek, J.; Szymanski, Z.; Werner, T.R. (Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires)

1991-01-24

Two discrete superdeformed (SD) bands have been identified in the nucleus {sup 147}Gd and the twin-band mechanism studied by comparison with SD results for {sup 146,148}Gd. Theoretical interprettion in terms of nucleonic orbitals with the Woods-Saxon potential is consistent with the pseudo-spin symmetry picture and the octupole susceptibility mechanism predicted by theory. (orig.).

Octupole correlations in superdeformed states

Energy Technology Data Exchange (ETDEWEB)

Nakatsukasa, T; Arita, K; Matsuyanagi, K [Kyoto Univ. (Japan). Dept. of Physics; Mizutori, S [Tokyo Univ., Tanashi (Japan). Inst. for Nuclear Study; Shimizu, Y R [Kyushu Univ., Fukuoka (Japan). Dept. of Physics

1992-08-01

We suggest that properties of single-particle motions in superdeformed nuclei may be significantly affected by coupling effects with low-frequency octupole vibrational modes with K = 0, 1, 2 and 3. We also indicate a possible relationship between octupole instability of superdeformed shape and supershell effects. In this connection, stability of classical periodic orbits and of KAM tori for single-particle motions in a reflection-asymmetric superdeformed potential are investigated. (author). 12 refs., 9 figs.

Search for superdeformation in {sup 144,145}Gd

Energy Technology Data Exchange (ETDEWEB)

Rzaca-Urban, T [Warsaw Univ. (Poland); Lieder, R M; Strahle, K; Utzelmann, S; Gast, W; Kutchin, D; Schnare, H [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Georgiev, A [Sofia Univ. (Bulgaria); Marti, G [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Dept. de Fisica; Spohr, K [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; [Hahn-Meitner-Institut Berlin GmbH (Germany); Brentano, P; Eberth, J; Eschenauer, M; Freund, S; Ott, E; Theuerkauf, J; Wolters, H; Zell, K O [Koeln Univ. (Germany). Inst. fuer Kernphysik; Maier, K H; Grave, H; Bach, C; Heese, J; Kluge, H; Schramm, M; Schubarth, R [Hahn-Meitner-Institut Berlin GmbH (Germany)

1992-08-01

Two experiments were performed and analyzed to search for superdeformation band in {sup 144,145}Gd by bombarding {sup 108,110}Pd targets with {sup 40A}r ions with energies of 182 and 189 MeV respectively, at the VICKSI accelerator of the Hahn-Meitner Institut, Berlin. The gamma radiation was measured with the OSIRIS spectrometer. An extended level system was proposed. 8 refs., 2 figs.

Lifetimes of the low spin states in the superdeformed band of {sup 192}Hg

Energy Technology Data Exchange (ETDEWEB)

Lee, I Y; Baktash, C; Cullen, D; Garrett, J D; Johnson, N R; McGowan, F K; Winchell, D F [Oak Ridge National Lab., TN (United States); Yu, C H [Tennessee Univ., Knoxville, TN (United States)

1992-08-01

Superdeformed (SD) states with a 2:1 axis ratio have been observed in nuclei in the A = 150, 190, and the actinide regions. These states depopulate into normally deformed (ND) states by gamma decay, but so far the linking transitions have not been observed and the depopulation mechanism is not fully understood. Nuclei in different mass regions decay out at states with different spin (I), excitation energy above the ND yrast line (U) and lifetime {tau}. This variation is due to differences in the nuclear properties such as the barrier penetration probability, the level densities and the gamma transition strength of SD and ND states. One important factor is the competition between the collective E2 decay along the SD band and the statistical decay to the ND states. These transition rates, or the partial lifetimes, can be determined if the lifetime and the intensity of the gamma rays depopulating the SD states are known. (author). 4 refs., 2 tabs., 2 figs.

A new relation of parameters of Bohr-Mottelson rotational spectra formula

International Nuclear Information System (INIS)

Li Mingliang; Xu Fuxin

2003-01-01

With the first three terms of Harris formula included and Mottelson's method followed, a new relation of the parameters of Bohr-Mottelson rotational spectra formula is brought forward. Superdeformed bands of even-even nuclei and normal deformed bands of nuclei in actinide and rare-earth are fitted with four-parameter Bohr-Mottelson rotational spectra formula. The relations of the parameters A, B, C, D are studied. The result show, for normal deformed bands, the new relation approach the experiment value in the same degree as the relation deduced from ab formula, but for superdeformed bands, the new relation is closer to the experiment than the relation deduced from ab formula. Three-parameter Harris formula may have better convergence than two-parameter Harris formula

Superdeformation in the mercury region

International Nuclear Information System (INIS)

Chasman, R.R.

1990-01-01

A brief history of superdeformation is presented. Calculations of superdeformed well depths, single particle energy level diagrams at I = 0, orbital alignments as a function of rotational frequency and dynamical moments of inertia are presented. The sensitivity of calculations to the details of the spin-orbit interaction are examined. Comparisons with experimental results are made. 37 refs., 9 figs

Shell model calculations at superdeformed shapes

International Nuclear Information System (INIS)

Nazarewicz, W.; Dobaczewski, J.; Van Isacker, P.

1991-01-01

Spectroscopy of superdeformed nuclear states opens up an exciting possibility to probe new properties of the nuclear mean field. In particular, the unusually deformed atomic nucleus can serve as a microscopic laboratory of quantum-mechanical symmetries of a three dimensional harmonic oscillator. The classifications and coupling schemes characteristic of weakly deformed systems are expected to be modified in the superdeformed world. The ''superdeformed'' symmetries lead to new quantum numbers and new effective interactions that can be employed in microscopic calculations. New classification schemes can be directly related to certain geometrical properties of the nuclear shape. 63 refs., 7 figs

Microscopic descriptions of the superdeformed bands in the region A 190: Bohr and Routhian Hamiltonians in the Hartree-Fock-Bogolyubov approximation; Descriptions microscopiques des bandes superdeformees dans la region A 190: Hamiltonien de Bohr et Routhian a l`approximation de Hartee-Fock-Bogolyubov

Energy Technology Data Exchange (ETDEWEB)

Libert, J. [Centre d`Etudes Nucleaires, Bordeaux-1 Univ., 33 Gradignan (France); Girod, M.; Delaroche, J-P.; Berger, J-F.; Romain, P.; Peru, S. [CEA Centre d`Etudes de Bruyeres-le-Chatel, 91 (France)

1997-06-01

The superdeformed bands of the nuclei in the region A = 190 were described by two microscopic approaches using Gogny D1 finite range interaction. The first one consists in building a Bohr Hamiltonian in the framework of Gauss overlap approximation (GOA) of the generator-coordinate method, starting from Hartree-Fock-Bogolyubov solutions under quadrupole constraints. This collective Hamiltonian microscopically determined for five quadrupolar variables is then diagonalized by a projection method on a collective based adapted to the large variety of the deformations to be considered. A special attention was given to the precise definition of the under-barrier collective wavefunctions (for which an original method of solving the collective Schroedinger equation was developed) in order to described correctly the lifetime of the shape isomeric states. The other approach, that of Routhian is based also on the Hartree-Fock-Bogolyubov approximation. The calculations are carried out with and without restoring the broken symmetry associated to the particle numbers (as given by Lipkin-Nogami). The results (excitation energies, moments of inertia, etc...) of the two calculation methods are compared with most recent experimental data. The existence of the superdeformed bands corresponding to vibrational excitations similar to those appearing in {beta} and {gamma} bands is proposed

Pairing field and moments of inertia of superdeformed nuclei

International Nuclear Information System (INIS)

Chen Yongjing; Chen Yongshou; Xu Fuxin

2002-01-01

The authors have systematically analysed the dynamic moments of inertia of the experimental superdeformed (SD) bands observed in the A = 190, 150 and 60-80 mass regions as functions of rotational frequency. By combining the different mass regions, the dramatic features of the dynamic moments of inertia were found and explained based on the calculations of the pairing fields of SD nuclei with the anisotropic harmonic oscillator quadrupole pairing Hartree-Fock-Bogoliubov model

From superdeformation to clusters

International Nuclear Information System (INIS)

Betts, R.R.

1992-01-01

Much of the discussion at this conference has centered on the topic of superdeformed states in nuclei, and their study with the exquisitely precise tool of gamma ray spectroscopy, carried out with state-of-the-art detector arrays. In the usual way in which superdeformed states are populated, via compound nucleus formation and evaporation, gamma decay is the last process to occur in the decay chain. In some other sense, it is also the last to occur in the meaning of least likely

Two-particle separation energy trends in the superdeformed well.

Science.gov (United States)

Wilson, A N; Korichi, A; Siem, S; Astier, A; Bazzacco, D; Bednarczyk, P; Bergström, M H; Chmel, S; Cullen, D M; Davidson, P M; Görgen, A; Hannachi, F; Hübel, H; Kintz, N; Lauritsen, T; Lopez-Martens, A; Lunardi, S; Naguleswaran, S; Nyakó, B M; Rejmund, M; Schönwasser, G; Schück, C; Sharpey-Schafer, J F; Timar, J; Wadsworth, R; Libert, J

2010-04-23

A measurement of the energy and spin of superdeformed states in 190Hg, obtained through the observation of transitions directly linking superdeformed and normal states, expands the number of isotopes in which binding energies at superdeformation are known. Comparison with neighboring nuclei shows that two-proton separation energies are higher in the superdeformed state than in the normal state, despite the lower Coulomb barrier and lower total binding energy. This unexpected result provides a critical test for nuclear models.

Evidence for octupole vibration in the superdeformed well of {sup 190}Hg from eurogam

Energy Technology Data Exchange (ETDEWEB)

Crowell, B.; Carpenter, M.P.; Janssens, R.V.F. [and others

1995-08-01

Gammasphere experiments in 1993-94 brought to light the existence of an excited superdeformed (SD) band in {sup 190}Hg with the unusual property of decaying entirely to the lowest (yrast) SD band over 3-4 transitions, rather than to the normally deformed states as is usually the case in the A {approximately} 150 and A {approximately} 190 regions of superdeformation. Although M1 transitions between signature-partner SD bands were previously observed in {sup 193}Hg, no such mechanism was available to explain the situation in the even-even nucleus {sup 190}Hg, whose yrast SD band has no signature partner. The best explanation appears to lie in long-standing theoretical predictions that the SD minimum in the potential energy surface would be quite soft with respect to octupole vibrations. This would lead to enhanced E1 transitions connecting the one-phonon and zero-phonon states. The data and this interpretation were published. A shortcoming of the Gammasphere experiments was that they did not allow the definitive measurement of the energies of the gamma-ray transitions connecting the two bands, due to the very weak population of the excited band ({approximately}0.05% of the {sup 190}Hg channel) and also partly, we believed, to the angular distributions of the transitions, which were peaked near 90 degrees, where Gammasphere had few detectors.

Two-particle separation energy trends in the superdeformed well.

Energy Technology Data Exchange (ETDEWEB)

Wilson, A. N.; Korichi, A.; Siem, S.; Astier, A.; Bazzacco, D.; Lauristen, T.; Physics; Australian National Univ.; CSNSM-IN2P3-CNRS; Univ. of Oslo; IPN Lyon; INFN

2010-04-23

A measurement of the energy and spin of superdeformed states in {sup 190}Hg, obtained through the observation of transitions directly linking superdeformed and normal states, expands the number of isotopes in which binding energies at superdeformation are known. Comparison with neighboring nuclei shows that two-proton separation energies are higher in the superdeformed state than in the normal state, despite the lower Coulomb barrier and lower total binding energy. This unexpected result provides a critical test for nuclear models.

On the feeding and spectroscopy of superdeformed states

International Nuclear Information System (INIS)

Aberg, S.

1987-03-01

Based on a cranked Nilsson calculation we discuss some spectroscopic properties of superdeformed nuclei, like quadrupole moments, g-factors, energies and moments of inertia. In light of recent experimental information about superdeformations in 152 Dy, possible feeding mechanisms of these states are discussed. The high-spin level density is calculated in a microscopic model, and the number of superdeformed states, compared to normal-deformed states, is found to be high for high spins and for low excitation energies. This suggests favoured regions in the (E exc ,I)-plane for the feeding of superdeformed states. A microscopic model for rotational damping is presented, and the E2-strength function up to about 4 MeV excitation energy is studied. The rotatinal cooling at 1 ≅ 50 in the superdeformed HD Dy is found to be much smaller than in the normal-deformed 168 Yb. (orig.)

Superdeformed bands in /sup 150/Gd and /sup 151/Tb: Evidence for the influence of high-N intruder states at large deformations

Energy Technology Data Exchange (ETDEWEB)

Fallon, P.; Alderson, A.; Bentley, M.A.; Bruce, A.M.; Forsyth, P.D.; Howe, D.; Roberts, J.W.; Sharpey-Schafer, J.F.; Twin, P.J.; Beck, F.A.

1989-02-16

Rotational bands, characteristic of a superdeformed prolate shape (epsilon approx. = 0.6) and extending to above spin 60 Planck constant, have been observed in both /sup 150/Gd and /sup 151/Tb. The magnitudes of the moments of inertia I/sup (2)/ were found to vary with frequency and the variation greatly exceeded that seen in /sup 148,149/Gd and /sup 151,152/Dy. The differences in the I/sup (2)/'s are attributed to the occupation of particular high-N orbitals. Moreover, contrary to the previous examples the bands in both /sup 150/Gd and /sup 151/Tb de-excited at a much higher rotational frequency of Planck constant..omega.. approx. = 0.4 MeV and this may indicate that the pair gap extends to higher frequencies in /sup 150/Gd and /sup 151/Tb.

''Identical'' bands in normally-deformed nuclei

International Nuclear Information System (INIS)

Garrett, J.D.; Baktash, C.; Yu, C.H.

1990-01-01

Gamma-ray transitions energies in neighboring odd- and even-mass nuclei for normally-deformed nuclear configurations are analyzed in a manner similar to recent analyses for superdeformed states. The moment of inertia is shown to depend on pair correlations and the aligned angular momentum of the odd nucleon. The implications of this analysis for ''identical'' super-deformed bands are discussed. 26 refs., 9 figs

The superdeformed isotope chains in the rare-earth region

International Nuclear Information System (INIS)

Dong Baoguo; Chen Yongshou; Jin Xingnan

1990-01-01

Self-consistent calculations with respect to ε 2 and γ based on the cranked Nilsson model were done systematically for the superdeformed rotational states of nuclei in the rare-earth region. The results indicate that there exist a number of super-deformed isotope chains with neutron number N = 80-86 and quadrupole deformation ε 2 0.5-0.6. The calculated minimum angular momentum at which the superdeformed state becomes yrast has an average value of 60 ℎ and increases as the number of neutron increases within the chain. The calculation of shell correction energy surface indicates that the contribution of the neutron system is mostly responsible for the super-deformation

Search and analysis of superdeformed and oblate states in 193Pb nucleus with the EUROGAM II multidetector array

International Nuclear Information System (INIS)

Ducroux, L.

1997-01-01

This work is devoted to the search and analysis of superdeformed and oblate states in 193 Pb nucleus. High spin states of this isotope, populated via fusion-evaporation reaction 168 Er ( 30 Si, 5n) 193 Pb, have been studied with the EUROGAM II γ multidetector array located near the VIVITRON accelerator in Strasbourg. New sorting and analysis programs have been developed in particular related to the background treatment. Angular distribution and linear polarisation analysis allowed us to assign the γ transition multipolarities. Five dipole bands, corresponding to a weakly oblate-deformed shape of the nucleus, have been observed and connected to the low-lying states. The level scheme has been considerably extended up to a spin of 61/2 ℎ and an excitation energy of about 8 MeV. These structures have been interpreted as based on a high-K two-quasi-proton excitation coupled to rotation aligned quasi-neutrons. Six superdeformed bands, corresponding to a high prolate-deformed shape of the nucleus, have been observed. These six bands have been interpreted as three pairs of signature partners based on quasineutron excitations. The extraction of the g-factor of a K=9/2 neutron superdeformed orbital has been done for the first time in lead isotopes, giving access to the magnetic properties of the extreme nuclear matter. All these results have been discussed in terms of microscopic mean field self-consistent Hartree-Fock calculations using the microscopic 'rotor + particle(s)' model. (author)

Kπ=1+ pairing interaction and moments of inertia of superdeformed rotational bands in atomic nuclei

International Nuclear Information System (INIS)

Hamamoto, I.; Nazarewicz, W.

1994-01-01

The effect of the pairing interaction coming from the rotationally induced K π =1 + pair-density on the nuclear moments of inertia is studied. It is pointed out that, contrary to the situation at normal deformations, the inclusion of the K π =1 + pairing may appreciably modify the frequency dependence of the moments of inertia at superdeformed shapes

Microscopic structure of high-spin vibrational states in superdeformed A=190 nuclei

Energy Technology Data Exchange (ETDEWEB)

Nakatsukasa, Takashi [Chalk River Labs., Ontario (Canada); Matsuyanagi, Kenichi [Kyoto Univ. (Japan); Mizutori, Shoujirou [Oak Ridge National Lab., TN (United States)] [and others

1996-12-31

Microscopic RPA calculations based on the cranked shell model are performed to investigate the quadrupole and octupole correlations for excited superdeformed (SD) bands in even-even A=190 nuclei. The K = 2 octupole vibrations are predicted to be the lowest excitation modes at zero rotational frequency. The Coriolis coupling at finite frequency produces different effects depending on the neutron and proton number of nucleus. The calculations also indicate that some collective excitations may produce moments of inertia almost identical to those of the yrast SD band. An interpretation of the observed excited bands invoking the octupole vibrations is proposed, which suggests those octupole vibrations may be prevalent in even-even SD A=190 nuclei.

Search and analysis of superdeformed and oblate states in {sup 193}Pb nucleus with the EUROGAM II multidetector array; Recherche et analyse des etats superdeformes et aplatis dans le noyau {sup 193}Pb a l'aide du multidetecteur EUROGAM II

Energy Technology Data Exchange (ETDEWEB)

Ducroux, L. [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire]|[Universite Claude Bernard, 69 - Lyon (France)

1997-01-09

This work is devoted to the search and analysis of superdeformed and oblate states in {sup 193}Pb nucleus. High spin states of this isotope, populated via fusion-evaporation reaction {sup 168}Er ({sup 30}Si, 5n) {sup 193}Pb, have been studied with the EUROGAM II {gamma} multidetector array located near the VIVITRON accelerator in Strasbourg. New sorting and analysis programs have been developed in particular related to the background treatment. Angular distribution and linear polarisation analysis allowed us to assign the {gamma} transition multipolarities. Five dipole bands, corresponding to a weakly oblate-deformed shape of the nucleus, have been observed and connected to the low-lying states. The level scheme has been considerably extended up to a spin of 61/2 {Dirac_h} and an excitation energy of about 8 MeV. These structures have been interpreted as based on a high-K two-quasi-proton excitation coupled to rotation aligned quasi-neutrons. Six superdeformed bands, corresponding to a high prolate-deformed shape of the nucleus, have been observed. These six bands have been interpreted as three pairs of signature partners based on quasineutron excitations. The extraction of the g-factor of a K=9/2 neutron superdeformed orbital has been done for the first time in lead isotopes, giving access to the magnetic properties of the extreme nuclear matter. All these results have been discussed in terms of microscopic mean field self-consistent Hartree-Fock calculations using the microscopic 'rotor + particle(s)' model. (author)

Search and analysis of superdeformed and oblate states in {sup 193}Pb nucleus with the EUROGAM II multidetector array; Recherche et analyse des etats superdeformes et aplatis dans le noyau {sup 193}Pb a l'aide du multidetecteur EUROGAM II

Energy Technology Data Exchange (ETDEWEB)

Ducroux, L [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; [Universite Claude Bernard, 69 - Lyon (France)

1997-01-09

This work is devoted to the search and analysis of superdeformed and oblate states in {sup 193}Pb nucleus. High spin states of this isotope, populated via fusion-evaporation reaction {sup 168}Er ({sup 30}Si, 5n) {sup 193}Pb, have been studied with the EUROGAM II {gamma} multidetector array located near the VIVITRON accelerator in Strasbourg. New sorting and analysis programs have been developed in particular related to the background treatment. Angular distribution and linear polarisation analysis allowed us to assign the {gamma} transition multipolarities. Five dipole bands, corresponding to a weakly oblate-deformed shape of the nucleus, have been observed and connected to the low-lying states. The level scheme has been considerably extended up to a spin of 61/2 {Dirac_h} and an excitation energy of about 8 MeV. These structures have been interpreted as based on a high-K two-quasi-proton excitation coupled to rotation aligned quasi-neutrons. Six superdeformed bands, corresponding to a high prolate-deformed shape of the nucleus, have been observed. These six bands have been interpreted as three pairs of signature partners based on quasineutron excitations. The extraction of the g-factor of a K=9/2 neutron superdeformed orbital has been done for the first time in lead isotopes, giving access to the magnetic properties of the extreme nuclear matter. All these results have been discussed in terms of microscopic mean field self-consistent Hartree-Fock calculations using the microscopic 'rotor + particle(s)' model. (author)

Primary transitions between the yrast superdeformed band and low-lying normal deformed states in {sup 194}Pb

Energy Technology Data Exchange (ETDEWEB)

Hauschild, K.; Bernstein, L.A.; Becker, J.A. [Lawrence Livermore National Lab., CA (United States)] [and others

1996-12-31

The observation of one-step `primary` gamma-ray transitions directly linking the superdeformed (SD) states to the normal deformed (ND) low-lying states of known excitation energies (E{sub x}), spins and parities (J{sup {pi}}) is crucial to determining the E{sub x} and J{sup {pi}} of the SD states. With this knowledge one can begin to address some of the outstanding problems associated with SD nuclei, such as the identical band issue, and one can also place more stringent restrictions on theoretical calculations which predict SD states and their properties. Brinkman, et al., used the early implementation of the GAMMASPHERE spectrometer array (32 detectors) and proposed a single, candidate {gamma} ray linking the {sup 194}Pb yrast SD band to the low-lying ND states in {sup 194}Pb. Using 55 detectors in the GAMMASPHERE array Khoo, et al., observed multiple links between the yrast SD band in {sup 194}Hg and the low-lying level scheme and conclusively determined E{sub x} and J of the yrast SD states. Here the authors report on an experiment in which Gammasphere with 88 detectors was used and the E{sub x} and J{sup {pi}} values of the yrast SD states in {sup 194}Pb were uniquely determined. Twelve one-step linking transitions between the yrast SD band and low-lying states in {sup 194}Pb have been identified, including the transition proposed by Brinkman. These transitions have been placed in the level scheme of {sup 194}Pb using coincidence relationships and agreements between the energies of the primary transitions and the energy differences in level spacings. Furthermore, measurements of angular asymmetries have yielded the multipolarities of the primaries which have allowed J{sup {pi}} assignments of the {sup 194}Pb SD states to be unambiguously determined for the first time without a priori assumptions about the character of SD bands. A study performed in parallel to this work using the EUROGAM-II array reports similar, but somewhat less extensive, results.

Necked-in superdeformed nuclei

International Nuclear Information System (INIS)

Joensson, L.O.

1997-03-01

In this dissertation the possibility of forming superdeformed states related to two connected spheres, having a more or less pronounced neck, is investigated. Detailed Nilsson-Strutinsky calculations with the cranked Woods-Saxon potential and a finite-range liquid drop model are carried out in the 180 Hg region, where superdeformed states related to two overlapping 90 Zr are predicted. Detailed spectroscopic properties are calculated. The effect of the necking degree of freedom on the giant dipole resonance, GDR, is investigated. The calculations are carried out with the Woods-saxon potential for the single-particle states, and the random phase approximation formalism for the phonon states. The residual interaction and coupling constants are determined by requirements of transitional invariance. The lower energy component of the GDR spectrum for superdeformed shapes, corresponding to vibrations along the symmetry axis, is diminished with increasing necking, and the mean energy of the GDR is increased. The folded Yukawa-plus-exponential liquid drop models take into account the finite range of the nuclear force, which is important when elongated and necked-in nuclear shapes are considered. However, it is shown that they are unstable towards higher multipole deformations, and that unphysical shapes are obtained in free minimizations when too high multipole deformations are included. Limits on multipolarity are given as functions of mass number. 9 refs., 4 figs

Decay-out from low-lying superdeformed bands in Pb isotopes: Tunneling widths in a two-level mixing model

International Nuclear Information System (INIS)

Wilson, A.N.; Davidson, P.M.

2004-01-01

A recently developed two-level mixing model of superdeformed decay is applied to evaluate the tunneling width between the superdeformed and normally deformed potential wells in 192 Pb and 194 Pb. Estimates are made of level densities and γ decay widths for levels in the normally deformed well, which are required for evaluation of the model. Experimental quasicontinuum results are used to suggest a spin-dependent reduction of the energy gap in the level spectrum, resulting in approximately constant level densities and decay widths in the normal well over the decay-out region for each isotope. However, it transpires that the model's prediction of the tunneling width is nearly independent of the normally deformed state widths for both isotopes. This observation is used to extract potential barrier heights for the two nuclei that depend mainly on experimentally determined values

Individual and collective excitations in the superdeformed nuclei of the 190 mass region; Excitations individuelles et collectives dans les noyaux superdeformes de la region de masse 190

Energy Technology Data Exchange (ETDEWEB)

Bouneau, Sandra [Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)

1997-04-11

This work aims at the study of different excitation modes, individual and collective, in superdeformed (SD) nuclei in the mass 190 region. The study of {sup 193}Tl and {sup 195,196,197}Bi SD nuclei brought information concerning individual excitation around the proton and neutron SD gaps Z = 80 - 82 and N = 112. Also, the study of the nucleus {sup 196}Pb revealed excited SD states built on collective vibrations. Concerning the isotope {sup 193}Tl, magnetic property analysis has been performed and allowed us to identify the proton intruder orbital {pi}i{sub 13/2} on which the two known SD the bands of the nucleus are build. It was possible to separate experimentally the relative contribution of proton and neutron pairing to the dynamic moment of inertia. Several {gamma} transition of high energy (about 3 MeV) linking SD states to normal deformed states (ND) and three new SD bands have been found in this nucleus. These SD bands have been interpreted in terms of individual excitations of the single proton on different orbitals identified above the proton SD gap Z = 80. An interaction between the states of two excited SD band have been observed and its strength measured. All these results (gyromagnetic factor, the role of nuclear pairing, excitation energy of the SD well, the interaction between two orbitals) represent information of theoretical interest. In each isotope {sup 195-197}Bi, one SD band has been discovered. They have been also interpreted in terms of individual excitation implying the same proton state. The study of this nuclei brought the first experimental proof that the superdeformation phenomenon persists above the shell closure Z = 82. In {sup 196}Pb nucleus a new excited SD band has been discovered. Observations are mentioned suggesting that we have to consider excitations different from those based on individual ones. An interpretation based on vibrational modes can explain both the low energy measured of the excited states in respect with the SD

First evidence for triaxial superdeformation in sup 1 sup 6 sup 1 Lu and sup 1 sup 6 sup 2 Lu

CERN Document Server

Bringel, P; Domscheit, J; Neusser, A; Schoenwasser, G; Singh, A K; Amro, H; Axiotis, M; Kröll, T; Napoli, D R; Bazzacco, D; Lunardi, S; Ur, C; Bhattacharya, S; Bhowmik, R; Hagemann, G B; Jensen, D R; Pancholi, S C; Petrache, C M

2003-01-01

High-spin states in sup 1 sup 6 sup 1 Lu and sup 1 sup 6 sup 2 Lu have been investigated using the GASP gamma-ray spectrometer array. Excited states in these nuclei have been populated through the sup 1 sup 0 sup 0 Mo( sup 6 sup 5 Cu, xn) reaction at a beam energy of 260 MeV. Four presumably triaxial superdeformed bands, three in sup 1 sup 6 sup 2 Lu and one in sup 1 sup 6 sup 1 Lu, have been observed. This is the first evidence for triaxial superdeformation in the two isotopes. (orig.)

Strength distribution of γ-transitions deexciting superdeformed rotational bands

International Nuclear Information System (INIS)

Lopez-Martens, A.P.; Doesing, T.; Khoo, T.L.; Korichi, A.; Hannachi, F.; Calderin, I.J.; Lauritsen, T.; Ahmad, I.; Carpenter, M.P.; Fischer, S.M.; Hackman, G.; Janssens, R.V.F.; Nisius, D.; Reiter, P.; Amro, H.; Moore, E.F.

1999-01-01

The strength distribution of the γ rays in the decay-out from superdeformed (SD) states is investigated by applying the maximum likelihood method, with special emphasis on the influence of the lower threshold given by experimental conditions. Clear graphical solutions are found, and a careful estimation of the dispersion in the values of the number of degrees of freedom and of the average strength of the most likely χ 2 distribution is carried out. For the 194 Hg nucleus, 41 primary transitions from the decay-out of SD states are identified above 2600 keV. It is concluded that they represent the strongest 10% of the transitions selected stochastically from a Porter-Thomas distribution. This would support the scenario of a statistical decay of SD states via coupling to a compound state at normal deformation. However, the occurrence of several very strong direct one-step transitions as previously observed in 194 Hg has a very small probability of the order of 10 -4 . This may indicate special selection rules governing the decay. However, based on the absence of strong primary transitions from SD states in adjacent nuclei, the situation in 194 Hg is viewed as a very lucky incidence

Spectrum of {gamma} rays connecting superdeformed and normal states in {sup 192}Hg

Energy Technology Data Exchange (ETDEWEB)

Henry, R.G.; Lauritsen, T.; Khoo, T.L. [and others

1995-08-01

Almost a hundred superdeformed bands were found in the mass 150 and 190 regions. Nevertheless, the energies and spins of the SD levels are still not measured (with one possible exception). Many attempts were made to decipher the highly-fragmented pathways connecting SD and normal states, but with hitherto no success. We adopted a new approach that consists of characterizing the overall spectral shape of the {gamma} rays linking SD and normal states.

Cranked relativistic Hartree-Bogoliubov theory: formalism and application to the superdeformed bands in the A∼190 region

International Nuclear Information System (INIS)

Afanasjev, A.V.; Ring, P.; Koenig, J.

2000-01-01

Cranked relativistic Hartree-Bogoliubov theory without and with approximate particle number projection by means of the Lipkin-Nogami method is presented in detail as an extension of relativistic mean field theory with pairing correlations to the rotating frame. Pairing correlations are taken into account by a finite range two-body force of Gogny type. The applicability of this theory to the description of rotating nuclei is studied in detail on the example of superdeformed bands in even-even nuclei of the A∼190 mass region. Different aspects such as the importance of pairing and particle number projection, the dependence of the results on the parametrization of the RMF Lagrangian and Gogny force, etc., are investigated in detail. It is shown that without any adjustment of new parameters the best description of experimental data is obtained by using the well established parameter sets NL1 for the Lagrangian and D1S for the pairing force. Contrary to previous studies at spin zero it is found that the increase of the strength of the Gogny force is not necessary in the framework of relativistic Hartree-Bogoliubov theory provided that particle number projection is performed

16O + 16O molecular structures of superdeformed states in S isotopes

Science.gov (United States)

Taniguchi, Y.

2017-06-01

Structures of excited states in S isotopes are investigated by using the antisymmetrized molecular dynamics and generator coordinate method (GCM). The GCM basis wave functions are calculated via energy variation with a constraint on the quadrupole deformation parameter β. By applying the GCM after parity and angular momentum projections, the coexistence of positive- and negative-parity superdeformed (SD) bands are predicted in 33-36S except for negative-parity states in 36S. The SD bands have structures of 16O + 16O + valence neutron(s) in molecular orbitals around the two 16O cores in a cluster picture. The configurations of the valence neutron(s) in the SD states are δ and/or π molecular orbitals.

Identical bands in Ba-Dy, N < 104 space

International Nuclear Information System (INIS)

Mittal, H.M.; Vidya Devi; Gupta, J.B.

2008-01-01

The recognition of the existence of identical bands, in even-even, odd-even and odd-odd nuclei, in normal deformed bands and superdeformed bands has become the subject of great interest in recent years. Here the search have been taken for such bands for the normal deformed, even-Z, even-N nuclei of Ba and Dy for 82< N<104 major shell space

From superdeformation to clusters

Energy Technology Data Exchange (ETDEWEB)

Betts, R R [Argonne National Lab., IL (United States). Physics Div.

1992-08-01

Much of the discussion at the conference centred on superdeformed states and their study by precise gamma spectrometry. The author suggests that the study of superdeformation by fission fragments and by auto-scattering is of importance, and may become more important. He concludes that there exists clear evidence of shell effects at extreme deformation in light nuclei studied by fission or cluster decay. The connection between the deformed shell model and the multi-center shell model can be exploited to give give insight into the cluster structure of these extremely deformed states, and also gives hope of a spectroscopy based on selection rules for cluster decay. A clear disadvantage at this stage is inability to make this spectroscopy more quantitative through calculation of the decay widths. The introduction of a new generation of high segmentation, high resolution, particle arrays has and will have a major impact on this aspect of the study of highly deformed nuclei. 20 refs., 16 figs.

Superdeformation in Pb isotopes

International Nuclear Information System (INIS)

Naz, Tabassum; Ahmad, Shakeb

2017-01-01

The Relatvistic Hartree-Bogoliubov (RHB) theory is used to explore the structure of superdeformed (SD) 190,212 Pb isotopes using the non-linear NL3* and density dependent (DD-ME2, DD-PC1) interactions. We have studied the the excitation energy, the potential depth and the deformation of these Pb isotopes

Study of link transitions between superdeformed well and normally deformed well in Hg{sup 192} and research and development for a new concept of {gamma} photons detection: the Agata array; Etude des liens entre puits superdeforme et puits normalement deforme dans {sup 192}Hg et recherche et developpement pour un nouveau concept de detection de photons {gamma}: le multidetecteur AGATA

Energy Technology Data Exchange (ETDEWEB)

Roccaz, J

2006-07-15

The atomic nucleus can adopt a very elongated shape with an axis ratio 2:1, this is the superdeformation phenomenon. Nowadays more than 300 superdeformed bands have been identified at high spin, but the determination of excitation energies, spins and parities of the associated states have been established for only one tenth of these bands. The former quantities (E{sup *}, I, {pi}) can only be determined via the linking gamma-transitions between the superdeformed (sd) and the normally deformed (nd) states. Within the framework of this thesis, we have investigated the Hg{sup 192} nucleus in order to establish E{sup *}, I and {pi}. This nucleus is predicted to be doubly magic at superdeformation and hence is taken as a reference in the mass {approx} 190 region. The experiment was carried out at Strasbourg using the Euroball-IV array and the vivitron accelerator. The obtained results are not convincing and seem to be at the limit of the performances of Euroball. Next generation of arrays will abandon the Compton-shields and use tracking concept to reconstruct the trajectories of incident photons, and therefore we expect a huge increase of efficiency. The second part of this work was focused on the research and development work for the AGATA (Advanced GAmma Tracking Array) project. We have performed simulations with the GEANT-4 code and developed tracking methods to reconstruct pair-creation events. The full AGATA will be operational around 2015 and will enhance by around two orders of magnitude the observational limits. (author)

New quantum mechanisms exhibited by superdeformed nuclei and their interpretations in terms of mean field and further; Nouveaux mecanismes quantiques manifestes par les noyaux superdeformes et leurs interpretations en terme de champ moyen et au-dela

Energy Technology Data Exchange (ETDEWEB)

El Aouad, N

1994-06-01

Identical superdeformed bands and quantized alignments have been investigated using the deformed Woods-Saxon mean field and a method of solving `exactly` the nuclear many-body problem with rotation. With the first formalism, an analysis method have been developed to find nucleonic configurations for bands in nuclei {sup 151}Tb, for the first three bands in nuclei {sup 149}Gd and for the bands in {sup 132}Ce. This method includes the calculation of incremental alignment which was performed for the first time. Such an approach allows to reproduce the experimental results and give an argument that the nuclear structure employed is correct. With the second formalism, it is shown that the deformed standard average-field plus pairing Hamiltonian with an induced rotation term employed for long time in literature, generates numerous twinned bands. The appearance of the twinned bands is shown to be often accompanied by the quantized incremental alignment. (author) 57 figs., 20 tabs., 66 refs.

The quasicontinuum of gamma rays from the feeding and decay of the superdeformed in 194Pb

International Nuclear Information System (INIS)

Lauritsen, T.; Ahmad, I.; Carpenter, M.P.

1995-01-01

Over the last year we developed techniques for the study of the quasicontinuum of gamma-rays from both the feeding and especially the decay of the superdeformed (SD) bands in the Hg nuclei, most notably 192 Hg. From this analysis we could extract both the spin and energy of some of the SD bands. The quasicontinuum analysis is the only technique so far that could extract these two fundamental properties of the now more than 100 SD bands found in the A = 150 and A = 190 regions. We based our understanding of the feeding and decay on comparisons of the data with extensive Monte Carlo simulations of the emission of gamma rays, both from the entry distribution toward the SD minimum, and, at lower spins, from the decay out of the SD band back to the states in the normal well

Nuclear superdeformation at high spins

International Nuclear Information System (INIS)

Dudek, J.

1991-01-01

The newly discovered forms of nuclear behavior at exotic shape configurations are discussed from the theoretical point of view. The main emphasis is set on superdeformed nuclei and the strange mechanisms influencing their properties. In particular the feeding properties, alignment, pairing properties and the problem of anomalous degeneracies are discussed

A new unexpected feature of superdeformed nuclei: strange degeneracies and their origin

International Nuclear Information System (INIS)

Dudek, J.

1990-01-01

Unexpected similarities between the superdeformed bands found recently in many nuclei of the mass A ∼ 150 and A ∼ 190 regions and the physical sense of this discovery are discussed. These similarities manifest themselves through the existence of nearly identical sequences of transitions belonging to two neighboring nuclei, and by now numerous nuclear pairs manifesting this feature have been found. The underlying microscopic mechanism is traced back to two independent effects: a readjustment of nuclear deformation diminishing the role of alignment of the least bound nucleus, and, the pseudospin symmetry, responsible for an approximate decoupling of the orbital and the intrinsic (pseudo) spin-degrees of freedom. 9 figs

Multiparticle excitations in the 149 Gd superdeformed nucleus. Signature of new C4 nucleus symmetry

International Nuclear Information System (INIS)

Theisen, C.

1995-01-01

The use of 8 π and EUROGAM phase I multi-detectors for the study of high spin states of 149 Gd nucleus has revealed unexpected new phenomenons about the superdeformation in this nucleus. The new excited bands confirm the omnipresence of twin bands phenomenon. A new multi-particle excitation (two protons and one neutron) has been discovered. Thanks to the second generation EUROGAM detector, unexpected discoveries such as C 4 symmetry, level interactions, complete backbending were obtained for the second potential well. The knowledge of interacting levels gives informations about the nucleon-nucleon residual interaction and could allow the determination of SD bands excitation energy. The complex processing and analysis of high multiplicity events has led to the development of new computing tools. An automatic band research program has been written for the discovery of new excited bands, and an exact method for the elimination of uncorrected events has been developed. The improvements of multi-detector performances should allow the discovery of more exceptional phenomenons and new anomalies in the SD bands. (J.S.). 222 refs., 86 figs., 38 tabs

Identical bands in (even, odd) nuclei as evidence for spectator nucleons

Energy Technology Data Exchange (ETDEWEB)

Schmeing, N C [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.

1992-08-01

An explanation is sought for ``identical`` moments of inertia for pairs of rotational bands in superdeformed nuclei differing in particle number. The authors postulate that certain nucleons do not participate in the collective rotation. The energy of superdeformed {sup 152}Dy has been calculated using this model with a deformed Woods-Saxon potential and full mixing of oscillator shells. A significant reduction in energy is achieved when the protons and neutron with asymptotic quantum number N < 4 constitute a nonrotating factor, as compared to the conventional prolate nucleus. 9 refs.

The quasicontinuum of gamma rays from the feeding and decay of the superdeformed in {sup 194}Pb

Energy Technology Data Exchange (ETDEWEB)

Lauritsen, T.; Ahmad, I.; Carpenter, M.P. [and others

1995-08-01

Over the last year we developed techniques for the study of the quasicontinuum of gamma-rays from both the feeding and especially the decay of the superdeformed (SD) bands in the Hg nuclei, most notably {sup 192}Hg. From this analysis we could extract both the spin and energy of some of the SD bands. The quasicontinuum analysis is the only technique so far that could extract these two fundamental properties of the now more than 100 SD bands found in the A = 150 and A = 190 regions. We based our understanding of the feeding and decay on comparisons of the data with extensive Monte Carlo simulations of the emission of gamma rays, both from the entry distribution toward the SD minimum, and, at lower spins, from the decay out of the SD band back to the states in the normal well.

Multiparticle excitations in the {sup 149} Gd superdeformed nucleus. Signature of new C{sub 4} nucleus symmetry; Excitations multiparticules dans le noyau superdeforme {sup 149}Gd. Signature d`une symetrie nouvelle C{sub 4} du noyau

Energy Technology Data Exchange (ETDEWEB)

Theisen, C

1995-01-01

The use of 8 {pi} and EUROGAM phase I multi-detectors for the study of high spin states of {sup 149} Gd nucleus has revealed unexpected new phenomenons about the superdeformation in this nucleus. The new excited bands confirm the omnipresence of twin bands phenomenon. A new multi-particle excitation (two protons and one neutron) has been discovered. Thanks to the second generation EUROGAM detector, unexpected discoveries such as C{sub 4} symmetry, level interactions, complete backbending were obtained for the second potential well. The knowledge of interacting levels gives informations about the nucleon-nucleon residual interaction and could allow the determination of SD bands excitation energy. The complex processing and analysis of high multiplicity events has led to the development of new computing tools. An automatic band research program has been written for the discovery of new excited bands, and an exact method for the elimination of uncorrected events has been developed. The improvements of multi-detector performances should allow the discovery of more exceptional phenomenons and new anomalies in the SD bands. (J.S.). 222 refs., 86 figs., 38 tabs.

Hartree-Fock description of superdeformed states

International Nuclear Information System (INIS)

Dobaczewski, J.; Meyer, J.

1991-10-01

The discovery of superdeformation has been preceded by theoretical predictions made in Nilsson-Strutinsky calculations and a description of the phenomenon still constitutes an exciting challenge to the theory of nuclear collective motion. In particular, a determination of electromagnetic transition rates requires a knowledge of microscopic collective wave functions, which can be achieved by using the Hartree-Fock (HF) theory and the generator coordinate method (GCM). In this study we present results of our calculations concerning the properties and superdeformed states in the mercury region. Using the GCM, we diagonalize the microscopic two-body hamiltonian within the basis set of constrained HF+BCS wave functions. The GCM provides values for the energy of the ground and excited states including the shape isomer which take into account the effect of correlations in the collective degree of freedom. The GCM will also allow us to discuss the qualitative modifications of the shape isomeric stability as induced by changes in pairing correlations

Searching triaxial superdeformation in 175Hf

International Nuclear Information System (INIS)

Li Xiaowei; Zhejiang Normal Univ., Jinhua; Yu Shaoying; Zhejiang Normal Univ., Jinhua; Chinese Academy of Sciences, Beijing; Shen Caiwan; National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou; Chen Yongshou; Chinese Academy of Sciences, Beijing; National Laboratory of Heavy Ion Accelerator of Lanzhou

2006-01-01

A two-dimensional Total Routhian Surface (TRS) calculation is carried out in order to ascertain if there is triaxial superdeformation in 175 Hf. A five quasi-particle configuration is chosen in the calculation. Unfortunately, the TRS minimum does not show up in the total potential energy surface. (authors)

Study of superdeformation in {sup 151,152}Tb isotopes using Eurogam multi-detector; Etude de la superdeformation dans les isotopes {sup 151,152}Tb a l`aide du multidetecteur Eurogam

Energy Technology Data Exchange (ETDEWEB)

Kharraja, E B

1994-06-01

The aim of this work is the study of {sup 151}Tb and {sup 152}Tb nuclei submitted to increasing speeds using the EUROGAM (phase I) multi-detector. The production of high angular momentum excited nuclei is obtained during {sup 130}Te({sup 27}Al,xn) fusion-evaporation reaction with a 154 MeV bombardment energy. For {sup 151}Tb nucleus, the diagram of high spin normal deformation levels is first determined to allow the analysis of bonds between SD structures and normally deformed states. In addition to the two SD bands already described for {sup 151}Tb nucleus, 8 new SD bands are described (6 for {sup 151}Tb nucleus and 2 for {sup 152}Tb nucleus) using triple and quadruple events analysis. The SD structure analysis gives important informations about nuclear superdeformation in this mass region, in particular about SD bands de-excitation, intrinsic configuration in the second potential well, and gamma transition energy degeneration between twin SD bands. A detailed description of EUROGAM 4{pi}{gamma} multi-detector (phase I and II), which comprises 42 Ge detectors with Compton suppression, is given. (J.S.). 98 refs., 100 figs., 22 tabs.

Spins of superdeformed rotational bands in Tl isotopes

Energy Technology Data Exchange (ETDEWEB)

Dadwal, Anshul; Mittal, H.M. [Dr. B.R. Ambedkar National Institute of Technology, Jalandhar (India)

2017-01-15

The two-parameter model defined for even-even nuclei viz. soft-rotor formula is used to assign the band-head spin of the 17 rotational bands in Tl isotopes. The least-squares fitting method is employed to obtain the spins of these bands in the A ∝ 190 mass region. The calculated transition energies are found to depend sensitively on the proposed spin. Whenever a correct spin assignment is made, the calculated and experimental transition energies coincide very well. The dynamic moment of inertia is also calculated and its variation with rotational frequency is explored. (orig.)

Beyond band termination in 157Er and the search for wobbling excitations in strongly deformed 174Hf

International Nuclear Information System (INIS)

Riley, M A; Djongolov, M K; Evans, A O

2005-01-01

High-spin terminating bands in heavy nuclei were first identified in nuclei around 158 Er 90 . While examples of special terminating states have been identified in a number of erbium isotopes, almost nothing is known about the states lying beyond band termination. In the present work the high-spin structure of 157 Er has been studied using the Gammasphere spectrometer. The subject of triaxial superdeformation and 'wobbling' modes in Lu nuclei has rightly attracted a great deal of attention. Very recently, four strongly or superdeformed (SD) sequences have been observed in 174 Hf and ultimate cranker calculations predict such structures may have significant triaxial deformation. We have performed two experiments in an attempt to verify the possible triaxial nature of these bands. A lifetime measurement was performed to confirm the large (and similar) deformation of the bands. In addition, a high-statistics, thin-target experiment was run to search for linking transitions between the SD bands and possible wobbling modes

Nature of the identical bands in atomic nuclei

International Nuclear Information System (INIS)

Szymanski, Z.

1995-01-01

Single-nucleon spectra in the fast rotating nuclei are shown to exhibit some special orbits that appear to be insensitive to nuclear rotation. It is suggested that the special orbits play an essential role in explaining the appearance and structure of the identical bands discovered in the superdeformed region. It is suggested that identical bands appear whenever the nucleonic orbit approaches the separatrix, i.e., a line dividing regions of different coupling schemes in a rotating mean field

Influence of i13/2 proton and j15/2 neutron intruding orbitals on the behaviour of 190 mass region superdeformed nuclei

International Nuclear Information System (INIS)

Duprat, J.

1995-01-01

This work concerns the study of the nuclear superdeformation phenomenon in the A = 190 mass region. The superdeformed (SD) states in 193 Tl, 194 Tl 195 Tl were produced via heavy-ion induced reactions and studied with the EUROGAM gamma multidetector array. The analysis of high-multiplicity events allowed the study of the magnetic properties of the SD states in these nuclei. For the first time, the g-factor of a proton orbital in a SD nucleus in the A = 190 mass region has been extracted. This measurement indicates that the two known bands in 195 Tl-SD are built on the i 13/2 proton intruder orbital. A new SD band has been found in this isotope: it is the first SD band built on an excited proton state found in the A = 190 region. Finally an interaction between two pairs of bands has been established in 194 Tl; this interaction indicate the crossing of two neutron orbitals above the N = 112 gap. The magnetic properties of the states of the SD bands in 194 Tl reveals that these bands are built on configurations in which the single proton and neutron intrinsic spins are aligned. Comparison between different SD bands in the Thallium isotopes shows the prominent role of the i 13/2 proton and the j 15/2 neutron intruder orbitals in the smooth increase of the dynamical moment of inertia as a function of the rotational frequency. In addition, this work reports on the first observation of a SD rotational band produced in a (HI, αxn) reaction channel. The study of the maximum spin reached by the SD bands indicates both a competition between alpha emission and fission of the compound nucleus, and the limitation due to the fission process in the population of the SD nuclei in the A = 190 region. (author). 120 refs., 112 figs., 22 tabs., 2 ann

Collective oblate bands in Pb nuclei

Energy Technology Data Exchange (ETDEWEB)

Huebel, H; Baldsefen, G; Mehta, D [Bonn Univ. (Germany). Inst. fuer Strahlen- und Kernphysik; and others

1992-08-01

The coexistence of different nuclear shapes is a well established phenomenon in the Hg-Pb region, where spherical, oblate, prolate and superdeformed prolate shapes have been observed. In this work, the authors report on several new rotational bands in the normally spherical nuclei {sup 199-201}Pb. Similar structures were found previously in the lighter isotopes {sup 197,198}Pb. 11 refs., 1 tab., 3 figs.

Influence of i{sub 13/2} proton and j{sub 15/2} neutron intruding orbitals on the behaviour of 190 mass region superdeformed nuclei; Influence des orbitales intruses proton i{sub 13/2} et neutron j{sub 15/2} sur le comportement des noyaux superdeformes de la region de masse 190

Energy Technology Data Exchange (ETDEWEB)

Duprat, J

1995-01-01

This work concerns the study of the nuclear superdeformation phenomenon in the A = 190 mass region. The superdeformed (SD) states in {sup 193}Tl, {sup 194}Tl {sup 195}Tl were produced via heavy-ion induced reactions and studied with the EUROGAM gamma multidetector array. The analysis of high-multiplicity events allowed the study of the magnetic properties of the SD states in these nuclei. For the first time, the g-factor of a proton orbital in a SD nucleus in the A = 190 mass region has been extracted. This measurement indicates that the two known bands in {sup 195}Tl-SD are built on the i{sub 13/2} proton intruder orbital. A new SD band has been found in this isotope: it is the first SD band built on an excited proton state found in the A = 190 region. Finally an interaction between two pairs of bands has been established in {sup 194}Tl; this interaction indicate the crossing of two neutron orbitals above the N = 112 gap. The magnetic properties of the states of the SD bands in {sup 194}Tl reveals that these bands are built on configurations in which the single proton and neutron intrinsic spins are aligned. Comparison between different SD bands in the Thallium isotopes shows the prominent role of the i{sub 13/2} proton and the j{sub 15/2} neutron intruder orbitals in the smooth increase of the dynamical moment of inertia as a function of the rotational frequency. In addition, this work reports on the first observation of a SD rotational band produced in a (HI, {alpha}xn) reaction channel. The study of the maximum spin reached by the SD bands indicates both a competition between alpha emission and fission of the compound nucleus, and the limitation due to the fission process in the population of the SD nuclei in the A = 190 region. (author). 120 refs., 112 figs., 22 tabs., 2 ann.

Search for low spin superdeformed states by transfer reactions

Energy Technology Data Exchange (ETDEWEB)

Blons, J; Goutte, D; Lepretre, A; Lucas, R; Meot, V; Paya, D; Phan, X H [DAPNIA SPhN CE Saclay 91191 Gif sur Yvette (France); Barreau, G; Doan, T P; Pedemay, G [CENBG, 33175 Gradignan (France); Becker, J A; Stoyer, M A [LLNL, Livermore, CA (United States)

1992-08-01

We present a specific experimental technique aiming to observe superdeformed isomeric states. Preliminary results on two proton transfer reaction on platinum targets leading to {sup 194}Hg are shown. (author). 6 refs., 5 figs.

Lifetimes of superdeformed states in {sup 194}Pb

Energy Technology Data Exchange (ETDEWEB)

Willsau, P; Hubel, H [Bonn Univ. (Germany). Inst. fuer Strahlen- und Kernphysik; Azaiez, F; Deleplanque, M A; Diamond, R M; Korten, W; Macchiavelli, A O; Stephens, F S [Lawrence Berkeley Lab., CA (United States); Kluge, H [Hahn-Meitner-Institut fuer Kernforschung Berlin G.m.b.H. (Germany); Hannachi, F [Paris-11 Univ., 91 - Orsay (France). Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse; Bacelar, J C [Kernfysisch Versneller Instituut, Zernikelaan 25 (Netherlands); Becker, J A; Brinkman, M J; Henry, E A; Kuhnert, A; Wang, T F [Lawrence Livermore National Lab., CA (United States); Draper, J A; Rubel, E [California Univ., Davis, CA (United States)

1992-08-01

Lifetimes of superdeformed states in {sup 194}Pb were measured by the Doppler-shift attenuation method. Quadrupole moments around 20 eb, that are constant over the observed frequency range, are derived. The results rule out large centrifugal stretching effects. 7 refs., 1 tab., 2 figs.

Shell structure in superdeformed nuclei at high rotational frequencies

International Nuclear Information System (INIS)

Ploszajczak, M.

1980-01-01

Properties of the shell structure in superdeformed nuclei at high rotational frequencies are discussed. Moreover, stability of the high spin compound nucleus with respect to the fission and the emission of light particles is investigated. (author)

Observation of states beyond band termination in 156,157,158Er and strongly deformed structures in 173,174,175Hf

International Nuclear Information System (INIS)

Riley, M A; Djongolov, M K; Evans, A O

2006-01-01

High-spin terminating bands in heavy nuclei were first identified in nuclei around 158 Er 90 . While examples of terminating states have been identified in a number of erbium isotopes, almost nothing is known about the states lying beyond band termination. In the present work, the high-spin structure of 156,157,158 Er has been studied using the Gammasphere spectrometer. The subject of triaxial superdeformation and 'wobbling' modes in Lu nuclei has rightly attracted a great deal of attention. Very recently four strongly or superdeformed (SD) sequences have been observed in 174 Hf, and cranking calculations using the Ultimate Cranker code predict that such structures may have significant triaxial deformation. We have performed two experiments in an attempt to verify the possible triaxial nature of these bands. A lifetime measurement was performed to confirm the large (and similar) deformation of the bands. In addition, a high-statistics, thin-target experiment took place to search for linking transitions between the SD bands, possible wobbling modes, and new SD band structures

Spectra of γ rays feeding superdeformed bands

International Nuclear Information System (INIS)

Lauritsen, T.; Khoo, T.L.; Henry, R.G.

1995-01-01

The spectrum of γrays coincident with SD transitions contains the transitions which populate the SD band. This spectrum can provide information on the feeding mechanism and on the properties (moment of inertia, collectivity) of excited SD states. We used a model we developed to explain the feeding of SD bands, to calculate the spectrum of feeding γrays. The Monte Carlo simulations take into account the trigger conditions present in our Eurogam experiment. Both experimental and theoretical spectra contain a statistical component and a broad E2 peak (from transitions occurring between excited states in the SD well). There is good resemblance between the measured and calculated spectra although the calculated multiplicity of an E2 bump is low by ∼30%. Work is continuing to improve the quality of the fits, which will result in a better understanding of excited SD states. In addition, a model for the last steps, which cool the γ cascade into the SD yrast line, needs to be developed. A strong M1/E2 low-energy component, which we believe is responsible for this cooling, was observed

Spectra of {gamma} rays feeding superdeformed bands

Energy Technology Data Exchange (ETDEWEB)

Lauritsen, T.; Khoo, T.L.; Henry, R.G. [and others

1995-08-01

The spectrum of {gamma}rays coincident with SD transitions contains the transitions which populate the SD band. This spectrum can provide information on the feeding mechanism and on the properties (moment of inertia, collectivity) of excited SD states. We used a model we developed to explain the feeding of SD bands, to calculate the spectrum of feeding {gamma}rays. The Monte Carlo simulations take into account the trigger conditions present in our Eurogam experiment. Both experimental and theoretical spectra contain a statistical component and a broad E2 peak (from transitions occurring between excited states in the SD well). There is good resemblance between the measured and calculated spectra although the calculated multiplicity of an E2 bump is low by {approximately}30%. Work is continuing to improve the quality of the fits, which will result in a better understanding of excited SD states. In addition, a model for the last steps, which cool the {gamma} cascade into the SD yrast line, needs to be developed. A strong M1/E2 low-energy component, which we believe is responsible for this cooling, was observed.

Superdeformation studies in {sup 150}Tb and {sup 153}Ho

Energy Technology Data Exchange (ETDEWEB)

Nisius, D.; Janssens, R.V.F.; Crowell, B. [and others

1995-08-01

There are now over 40 superdeformed (SD) bands known in the A {approximately} 150 region and in most cases the properties of these bands are understood in terms of single-particle excitations in the absence of pairing. By continuing the search for new SD bands we hope to gain insight into (1) the ordering of the proton and neutron orbitals near the Fermi surface in the SD well, (2) the effects that the alignment of those orbitals has on the moments of inertia, and (3) the collective excitations in the SD well. For {sup 150}Tb, which is one proton and one neutron away from the SD doubly-magic nucleus {sup 152}Dy, it should be possible to study SD bands based on both proton and neutron hole excitations. By adding one proton to the {sup 152}Dy nucleus (i.e. {sup 153}Ho) proton excitations above the Z = 66 shell gap can be studied. These excitations are important as calculations suggested that the proton intruder orbital N = 7 might become occupied. Interactions between this orbital and a N = 5 level may result in softness towards octupole vibrations. High spin states in {sup 150}Th and {sup 153}Ho were populated using the {sup 124}Sn({sup 31}P,5n) and {sup 120}Sn({sup 37}Cl,4n) reactions, respectively. In both cases the early implementation phase of Gammasphere was used to detect the decay gamma rays and over 1 x 10{sup 9} triple and higher fold coincidence events were recorded. In {sup 150}Tb, the data analysis is complete and two new SD bands were identified. The fact that Im{sup (2)} moments of inertia are sensitive to the specific high-N intruder content of the SD bands was used to suggest configurations for the two new bands. A paper reporting these results is being prepared. For {sup 153}Ho, data analysis is still in its early stages.

Exotic nuclear shapes - Axial and nonaxial octupoles at normal and at super-deformation

Energy Technology Data Exchange (ETDEWEB)

Skalski, J [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland); [Universite Libre de Bruxelles (Belgium); Heenen, P [Universite Libre de Bruxelles (Belgium); Bonche, P [CEA Centre d` Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Centre d` Application et de Promotion des Rayonnements Ionisants; Flocard, H [Paris-11 Univ., 91 - Orsay (France); Meyer, J [Lyon-1 Univ., 69 - Villeurbanne (France)

1992-08-01

We have studied collective octupole dynamics including nonaxial components of the octupole mean field, mainly at superdeformed shape in the Hg-Pb region. Both the Strutinsky method combined with cranking and the generator coordinate method within the self-consistent Hartree-Fock basis suggest the existence of collective octupole excitations at the superdeformed minima. GCM calculations point out to the E1 transitions as their most prominent experimental manifestation. We also comment on the nonaxial octupole components influence on octupole dynamics in traditional octupole region of Ra-Th nuclei. (author). 38 refs., 6 figs.

Description of the turnover of the dynamical moment of inertia of the superdeformed nuclear state

International Nuclear Information System (INIS)

Yuxin Liu; Jiangang Song; Hong-zhou Sun; Jia-jun Wang; En-guang Zhao

1998-01-01

We propose in this paper an approach to describe the dynamical moment of inertia of superdeformed nuclear states in the spirit of variable moments of inertia. Both the general changing feature and the turnover of dynamical moments of inertia with rotational frequency are well described in our approach. It indicates that the competition between the angular momentum driving effect and the restraining effect plays a crucial role in determining the dynamical moments of inertia of superdeformed nuclear states. (author)

Fermion dynamical symmetry and identical bands

International Nuclear Information System (INIS)

Guidry, M.

1994-01-01

Recent general attention has been directed to the phenomenon of identical bands in both normally deformed and superdeformed nuclei. This paper discusses the possibility that such behavior results from a dynamical symmetry of the nuclear many-body system. Phenomenology and the basic principles of Lie algebras are used to place conditions on the acceptable properties of a candidate symmetry. We find that quite general arguments require that such a symmetry have a minimum of 21 generators with a microscopic fermion interpretation

Symmetries of the nuclear average field hamiltonian and a search for possible exotic equilibrium deformations in superdeformed nuclei

Energy Technology Data Exchange (ETDEWEB)

Li Xunjun; Dudek, J.; Romain, P. (Centre de Recherches Nucleaires, IN2P3-CNRS, Univ. Louis Pasteur, 67 - Strasbourg (France))

1991-11-21

Symmetry properties of the general average-field hamiltonian-matrix resulting from the geometrical symmetries of the hamiltonian itself are derived and discussed. The corresponding numerical algorithms are constructed. Total energy calculations for superdeformed nuclei are then extended to include the usually neglected deformation modes {alpha}{sub {lambda}=3{mu}{ne}0} in the expansion of the nuclear surface expression R({theta}, {phi}; {l brace}{alpha}{r brace})=c({l brace}{alpha}{r brace})R{sub 0}(1+{Sigma}{sub {lambda}} {Sigma}{sub {mu}=-{lambda}}{sup {lambda}} {alpha}{sub {lambda}{mu}}{sup *}{Upsilon}{sub {lambda}{mu}}({theta}, {phi})). The general trends in the shell-energy dependence on {alpha}{sub {lambda}=3{mu}} and the implied instabilities in the superdeformed configurations of the rare earth nuclei are studied using the Strutinsky formula with the macroscopic part taken in the form of the folded-Yukawa plus exponential interaction. A possibility of new (double superdeformed minimum) structures coexisting in some nuclei and resulting from the proton shell effects is predicted and illustrated. No significant neutron effects are found in the rare earth superdeformed nuclei considered. (orig.).

g factors and the interplay of collective and single-particle degrees of freedom in superdeformed mass-190 nuclei

International Nuclear Information System (INIS)

Sun, Yang; Zhang, Jing-ye; Guidry, Mike

2001-01-01

Interplay of collective and single-particle degrees of freedom is a common phenomenon in strongly correlated many-body systems. Despite many successful efforts in the study of superdeformed nuclei, there is still unexplored physics that can be best understood only through the nuclear magnetic properties. We point out that study of the gyromagnetic factor (g factor) may open a unique opportunity for understanding superdeformed structure. Our calculations suggest that investigation of the g-factor dependence on spin and particle number can provide important information on single-particle structure and its interplay with collective motion in the superdeformed mass-190 nuclei. Modern experimental techniques combined with the new generation of sensitive detectors should be capable of testing our predictions

Microscopic structure of superdeformed states in Th, U, Pu and Cm isotopes with Gogny force

International Nuclear Information System (INIS)

Girod, M.; Delaroche, J.P.; Romain, P.; Libert, J.

2002-01-01

The structure properties of the even-even nuclei 226, 228, 230, 232, 234 Th, 230, 232, 234, 236, 238, 240 U, 240, 242, 244, 246 Pu, and 242, 244, 246, 248 Cm have been investigated at normal and superdeformed shapes in microscopic mean-field calculations based on Gogny force. Collective levels are predicted from constrained Hartree-Fock-Bogoliubov and configuration mixing calculations. Two quasiparticle states are also predicted from blocking calculations for neutron and proton configurations. Predictions are shown and compared with experimental data at superdeformed shapes. (orig.)

Study of superdeformation at zero spin with Skyrme-Hartree-Fock method

Energy Technology Data Exchange (ETDEWEB)

Takahara, S; Tajima, N; Onishi, N [Tokyo Univ. (Japan)

1998-03-01

Superdeformed (SD) bands have been studied extensively both experimentally and theoretically in the last decade. Since the first observation in {sup 152}Dy in 1986, SD bands have been found in four mass regions, i.e., A {approx} 80, 130, 150 and 190. While these SD bands have been observed only at high spins so far, they may also be present at zero spin like fission isomers in actinide nuclei: The familiar generic argument on the strong shell effect at axis ratio 2:1 does not assume rotations. If non-fissile SD isomers exist at zero spin, they may be utilized to develop new experimental methods to study exotic states, in a similar manner as short-lived high-spin isomers are planned to be utilized as projectiles of fusion reactions in order to populate very high-spin near-yrast states. They will also be useful to test theoretical models whether the models can describe correctly the large deformations of rare-earth nuclei without further complications due to rotations. In this report, we employ the Skyrme-Hartree-Fock method to study the SD states at zero spin. First, we compare various Skyrme force parameter sets to test whether they can reproduce the extrapolated excitation energy of the SD band head of {sup 194}Hg. Second, we systematically search large-deformation solutions with the SkM{sup *} force. The feature of our calculations is that the single-particle wavefunctions are expressed in a three-dimensional-Cartesian-mesh representation. This representation enables one to obtain solutions of various shapes (including SD) without preparing a basis specific to each shape. Solving the mean-field equations in this representation requires, however, a large amount of computation which can be accomplished only with present supercomputers. (author)

Fermion dynamical symmetry and identical bands

International Nuclear Information System (INIS)

Guidry, M.

1995-01-01

Recent general attention has been directed to the phenomenon of identical bands in both normally deformed and superdeformed nuclei. This paper discusses the possibility that such behavior results from a dynamical symmetry of the nuclear many-body system. Phenomenology and the basis principles of Lie algebras are used to place conditions on the acceptable properties of a candidate symmetry. We find that quite general arguments require that such a symmetry have a minimum of 21 generators with a microscopic fermion interpretation. (author). 9 refs., 11 figs., 1 tab

Nuclear shape evolution starting from superdeformed state. Role of two-body collision and rotation

International Nuclear Information System (INIS)

Liu, Yu-xin; Sakata, Fumihiko

1999-01-01

With the nuclear density distribution being simulated by the Boltzmann Uehling-Uhlenbeck equation and Vlasov equation with several rotational frequencies, the time evolution of the quadrupole moment of nucleus 86 Zr starting with superdeformed shape is studied. The contribution of two-body collisions and the effects of collective rotation to the shape evolution is investigated. The numerical results indicate that the two-body collisions play a role of damping on the evolution from a superdeformed shape to a normal deformed one in a case without rotation. In a case of rotation with lower frequency, the two-body collisions accelerate the evolution process. A new role of the collective rotation to enhance the nuclear fission is proposed. (author)

Microscopic structure of superdeformed states in Th, U, Pu and Cm isotopes with Gogny force

Energy Technology Data Exchange (ETDEWEB)

Girod, M.; Delaroche, J.P.; Romain, P. [CEA/DIF, DPTA/SPN, Boite Postale 12, 91680 Bruyeres-le-Chatel (France); Libert, J. [Institut de Physique Nucleaire Centre National de la Recherche Scientifique-IN2P3, F-91406 Orsay (France)

2002-10-01

The structure properties of the even-even nuclei {sup 226,} {sup 228,} {sup 230,} {sup 232,} {sup 234}Th, {sup 230,} {sup 232,} {sup 234,} {sup 236,} {sup 238,} {sup 240}U, {sup 240,} {sup 242,} {sup 244,} {sup 246}Pu, and {sup 242,} {sup 244,} {sup 246,} {sup 248}Cm have been investigated at normal and superdeformed shapes in microscopic mean-field calculations based on Gogny force. Collective levels are predicted from constrained Hartree-Fock-Bogoliubov and configuration mixing calculations. Two quasiparticle states are also predicted from blocking calculations for neutron and proton configurations. Predictions are shown and compared with experimental data at superdeformed shapes. (orig.)

Generalized vibrating potential model for collective excitations in spherical, deformed and superdeformed systems: (1) atomic nuclei, (2) metal clusters

International Nuclear Information System (INIS)

Nesterenko, V.O.; Kleinig, W.

1995-01-01

The self-consistent vibrating potential model (VPM) is extended for description of Eλ collective excitations in atomic nuclei and metal clusters with practically any kind of static deformation. The model is convenient for a qualitative analysis and provides the RPA accuracy of numerical calculations. The VPM is applied to study Eλ giant resonances in spherical metal clusters and deformed and superdeformed nuclei. It is shown that the deformation splitting of superdeformed nuclei results in a very complicated (''jungle-like'') structure of the resonances, which makes the experimental observation of E2 and E3 giant resonances in superdeformed nuclei quite problematic. Calculations of E1 giant resonance in spherical sodium clusters Na 8 , Na 20 and Na 40 are presented, as a test of the VPM in this field. The results are in qualitative agreement with the experimental data. (orig.)

Microscopic descriptions of collective SD bands in the A=190 mass region with the Gogny force

International Nuclear Information System (INIS)

Girod, M.

1997-01-01

In the framework of microscopic models, we present two methods for describing superdeformed (SD) band properties. The first one is the cranked Hartree-Fock-Bogolyubov (HFB) method, without and with inclusion of particle number projection. The second one is the Gaussian overlap approximation to the generator coordinate method (GCM+GOA) with which we treat the five quadrupole collective coordinates. Both methods use the Gogny force. Moments of inertia and excitation energies of SD bands are calculated and compared with experimental results. (orig.). With 1 fig

The spin-orbit interaction and SU(3) generators in superdeformation

Energy Technology Data Exchange (ETDEWEB)

Sugawara-Tanabe, K [School of Social Information, Otsuma Women` s University, Tokyo (Japan); Arima, A [Tokyo Univ. (Japan). Dept. of Physics

1992-08-01

The authors found that the effect of spin-orbit coupling becomes smaller for the parity doublet level and for some other levels around superdeformation. This is because of the strongly deformed quadrupole field, which indicates the L-S coupling scheme is recovered for these levels. These levels can be described by an SU-3 group with eight generators and a Casimir operator. 6 refs., 3 figs.

Some general constraints on identical band symmetries

International Nuclear Information System (INIS)

Guidry, M.W.; Strayer, M.R.; Wu, C.; Feng, D.H.

1993-01-01

We argue on general grounds that nearly identical bands observed for superdeformation and less frequently for normal deformation must be explicable in terms of a symmetry having a microscopic basis. We assume that the unknown symmetry is associated with a Lie algebra generated by terms bilinear in fermion creation and annihilation operators. Observed features of these bands and the general properties of Lie groups are then used to place constraints on acceptable algebras. Additional constraints are placed by assuming that the collective spectrum is associated with a dynamical symmetry, and examining the subgroup structure required by phenomenology. We observe that requisite symmetry cannot be unitary, and that the simplest known group structures consistent with these minimal criteria are associated with the Ginocchio algebras employed in the fermion dynamical symmetry model. However, our arguments are general in nature, and we propose that they imply model-independent constraints on any candidate explanation for identical bands

Decay out of the yrast and excited highly-deformed bands in the even-even nucleus {sup 134}Nd

Energy Technology Data Exchange (ETDEWEB)

Petrache, C.M.; Bazzacco, D.; Lunardi, S. [Sezione di Padova (Italy)] [and others

1996-12-31

The resolving power achieved by the new generation of {gamma}-ray detector arrays allows now to observe transitions with intensities of the order of {approximately}10{sup {minus}3} of the population of the final residual nucleus, making therefore feasible the study of the very weakly populated excited bands built on the superdeformed (SD) minimum or of the decay out of the SD bands. As a matter of fact, numerous excited SD bands have been observed in the different regions of superdeformation, which led to a deeper understanding of the single-particle excitation in the second minimum. The first experimental breakthrough in the study of the decay out process has been achieved in the odd-even {sup 133,135}Nd nuclei of the A=130 mass region. There, the observation of the discrete linking transitions has been favored by the relatively higher intensity of the highly-deformed (HD) bands ({approximately}10%), as well as by the small excitation energy with respect to the yrast line in the decay-out region ({approximately}1 MeV). No discrete linking transitions have been so far observed in the A=80, 150 mass regions. The present results suggest that the decay out of the HD bands in {sup 134}Nd is triggered by the crossing with the N=4 [402]5/2{sup +} Nilsson orbital, that has a smaller deformation than the corresponding N=6 intruder configuration. The crossing favours the mixing with the ND rotational bands strongly enhancing the decay-out process and weakening the in-band transition strength. The HD band becomes fragmented and looses part of its character. The intensity of the decay-out transitions increases when the spin of the HD state decreases, indicating enhanced ND amplitude in the wavefunction when going down the band. Lifetime measurements of the HD bands are crucial to further elucidate the decay-out process.

ΔI = 2 Nuclear Staggering in Superdeformed Rotational Bands

Directory of Open Access Journals (Sweden)

Okasha M. D.

2014-01-01

Full Text Available A four parameters model including collective rotational en ergies to fourth order is ap- plied to reproduce the ∆ I = 2 staggering in transition energies in four selected super deformed rotational bands, namely, 148 Gd (SD6, 194 Hg (SD1, SD2, SD3. The model parameters and the spin of the bandhead have been extracted a ssuming various val- ues to the lowest spin of the bandhead at nearest integer, in o rder to obtain a minimum root mean square deviation between calculated and the exper imental transition energies. This allows us to suggest the spin values for the energy level s which are experimentally unknown. For each band a staggering parameter represent the deviation of the transition energies from a smooth reference has been determined by calc ulating the fourth order derivative of the transition energies at a given spin. The st aggering parameter contains five consecutive transition energies which is denoted here a s the five-point formula. In order to get information about the dynamical moment of ine rtia, the two point for- mula which contains only two consecutive transition energi es has been also considered. The dynamical moment of inertia decreasing with increasing rotational frequency for A ∼ 150, while increasing for A ∼ 190 mass regions.

Collectivity of dipole bands in {sup 196}Pb

Energy Technology Data Exchange (ETDEWEB)

Carpenter, M.P.; Liang, Y.; Janssens, R.V.F. [and others

1995-08-01

The region of nuclei with mass {approximately} 190 was studied extensively over the last few years following the discovery of superdeformation in {sup 190}Hg. More recently, considerable interest in the neutron-deficient Pb isotopes developed with the discover of a number of bands at high spin connected by dipole transitions in both even {sup 192-200}Pb and odd {sup 197-201}Pb nuclei. The majority of the dipole bands are regular in character (i.e. transition energies increase smoothly with spin) while the remaining bands are referred to as irregular in character, due to the fact that the transition energies do not increase smoothly with spin. The properties of the dipole bands were interpreted in terms of high-K, moderately-deformed oblate states built on configurations involving high-J, shape-driving quasiproton excitations coupled to rotation-aligned quasineutrons. It was suggested that the difference between the regular and irregular dipole sequences is related to the deformation where the irregular sequences are thought to be less collective than their regular counterparts.

l-dependent potential barriers and superdeformed states

International Nuclear Information System (INIS)

Gherghescu, R.A.; Royer, G.

1999-01-01

The macroscopic-microscopic energy of rotating nuclei moving in the fusion-like deformation valley has been determined within a generalized liquid drop model including the nuclear proximity energy, the two-center shell model and the Strutinsky method. The l-dependent potential barriers of the 84 Zr, 132 Ce, 152 Dy and 192 Hg nuclei have been determined. A first minimum having a pure microscopic origin and lodging the normally deformed states, progressively disappears with increasing angular momenta. The microscopic and macroscopic energies contribute to generate a second minimum where superdeformed states may survive. It becomes progressively the lowest one at intermediate spins. At still higher angular momenta, the minimum moves towards the foot of the external fission barrier leading to macroscopic hyper-deformed quasi-molecular states. (authors)

Staggering in signature partners of A∼190 mass region of superdeformed rotational bands

International Nuclear Information System (INIS)

Uma, V.S.; Goel, Alpana; Yadav, Archana

2014-01-01

This paper discuss about ΔI=1 signature splitting in signature partner pairs of A∼190 mass region. Around twenty signature partner pairs (usually called as two bands, each with a fixed signature) have been reported in this mass region. For these signature pairs, band head moment of inertia (J 0 ) and intrinsic structure of each pair of signature partners have been found as almost identical. Also, these signature partner pairs showed large amplitude signature splitting. As each of the two signature partner forms a regular spin sequence and signature bands are not equivalent in terms of energies. This difference in energies results in signature splitting

Search for and study of linking transitions between super- and normal deformed wells in the {sup 151}Tb nucleus; Recherche et etude de transitions de liaison entre les puits super- et normalement deformes dans le noyau {sup 151}Tb

Energy Technology Data Exchange (ETDEWEB)

Robin, J

2003-12-01

While the superdeformation phenomenon has been observed many times in different mass regions, the excitation energy and angular momentum are not known for most of the superdeformed bands, mainly in the A {approx} 150 mass region. We have thus undertaken the search for and study of linking transitions between super and normal deformed potential wells in the Tb{sup 151} nucleus with the EUROBALL-IV spectrometer based at the subatomic research institute of Strasbourg. This nucleus presents the peculiarity of having an excited superdeformed band identical to the yrast one of Dy{sup 152}, which has recently been linked to normal deformed states. As the Dy{sup 152} nucleus exhibits a shape coexistence in the first potential well, we have also searched for collective rotational bands with prolate but moderate shape, coexisting with the oblate structure of Tb{sup 151}. The discovery of new superdeformed bands in the Tb{sup 151,152} isotopes, the extension to lower and higher spins of the previously known bands, and mean field calculations with a deformed Woods-Saxon potential have contributed to improve our knowledge as well as raise new questions on the orbitals configuration assignments of these bands. (author)

Search for and study of linking transitions between super- and normal deformed wells in the 151Tb nucleus

International Nuclear Information System (INIS)

Robin, J.

2003-12-01

While the superdeformation phenomenon has been observed many times in different mass regions, the excitation energy and angular momentum are not known for most of the superdeformed bands, mainly in the A ∼ 150 mass region. We have thus undertaken the search for and study of linking transitions between super and normal deformed potential wells in the Tb 151 nucleus with the EUROBALL-IV spectrometer based at the subatomic research institute of Strasbourg. This nucleus presents the peculiarity of having an excited superdeformed band identical to the yrast one of Dy 152 , which has recently been linked to normal deformed states. As the Dy 152 nucleus exhibits a shape coexistence in the first potential well, we have also searched for collective rotational bands with prolate but moderate shape, coexisting with the oblate structure of Tb 151 . The discovery of new superdeformed bands in the Tb 151,152 isotopes, the extension to lower and higher spins of the previously known bands, and mean field calculations with a deformed Woods-Saxon potential have contributed to improve our knowledge as well as raise new questions on the orbitals configuration assignments of these bands. (author)

Single-step link of the superdeformed band in 143Eu

International Nuclear Information System (INIS)

Atac, A.; Bergstroem, M.H.; Nyberg, J.; Persson, J.; Herskind, B.; Joss, D.T.; Lipoglavsek, M.; Tucek, K.

1996-01-01

A discrete γ-ray ransition with an energy of 3360.6 keV deexciting the second lowest SD state in 143 Eu has been discovered. It carries 3.2 % of the full intensity of the band and feeds into a nearly spherical state which is above the I = 35/2 (+) , E x =4947 keV level. The exact placement of the single-step link is, however, not established due to the specially complicated level scheme in the region of interest. The energy of the single-step link agrees well with the previously determined two-step links. (orig.)

Nuclear moments of inertia inferred from wobbling motion in the triaxial superdeformed nuclei

International Nuclear Information System (INIS)

Matsuzaki, Masayuki; Shimizu, Yoshifumi R.; Matsuyanagi, Kenichi

2003-01-01

The three moments of inertia associated with the wobbling mode built on the triaxial superdeformed states in Lu-Hf region are investigated by means of the cranked shell model plus random-phase approximation to the configurations with aligned quasiparticle(s). The result indicates that it is crucial to take into account the direct contribution to the moments of inertia from the aligned quasiparticle(s)so as to realize T x > T y in positive-γ shapes. (author)

Alpha particle spectra in coincidence with normal and superdeformed states in {sup 150}Tb

Energy Technology Data Exchange (ETDEWEB)

Viesti, G.; Lunardon, M.; Bazzacco, D. [dell`Universita, Padova (Italy)]|[INFN, Padova (Italy)] [and others

1996-12-31

The study of correlations between particle evaporation from highly excited compound nuclei at large angular momenta and the states in the final evaporation residues (ER) is a field of investigation which has been opened, in the last years, with the advent of the new large {gamma}-ray arrays. It is now possible to correlate the evaporation spectra to various bands with shapes ranging from spherical to superdeformed (SD) in the same final nucleus. It is generally accepted that the particle evaporation from the compound nucleus is chaotic and that only in the near-yrast {gamma} cascade, where the feeding of different classes of states takes place, the ordered motion is restored. The sensitivity of the particle spectra on the feeding of specific states in the residual nuclei can be taken as an indication that additional degrees of freedom might be important in the evaporation process or that particular regions of the phase space open to the decay populate preferentially some selected structures in the final cold nucleus. This latter point is important for the understanding of the feeding mechanism of SD states. Several experiments performed so far did not find a clear dependence of the shapes of the particle spectra on the excited states having different deformations in the ER. For example, the proton spectra in coincidence with transitions in the SD bands of {sup 133}Nd and {sup 152}Dy nuclei were found to be similar to those in coincidence with transitions in the normal deformed (ND) bands. Alpha particles have been proposed since long as a sensitive probe of the deformation of the emitting nucleus. Results are presented here of an experiment in which the authors have measured the energy spectra of alpha particles associated with different classes of states (ND and SD) in the {sup 150}Tb nucleus populated in the reaction {sup 37}Cl({sup 120}Sn, {alpha}3n{gamma}){sup 150}Tb.

Gamma multi-detectors and nuclear structure studies: search for superdeformed structures in {sup 147}Gd and {sup 144}Gd isotopes using Crystal Castle; simulation calculations for EUROGAM multi-detector definition; Multidetecteurs gamma et etudes de structure nucleaire: recherche avec le Chateau de Cristal de structures superdeformees dans les isotopes {sup 147}Gd et {sup 144}Gd; calculs de simulation pour la definition du multidetecteur EUROGAM

Energy Technology Data Exchange (ETDEWEB)

France, G de

1992-12-31

Computer simulations have been used for the calculation of the new generation of 4 {pi}{gamma} multi-detectors (Castle Crystal) of EUROGAM system (phase I and II). Two superdeformed bands (I and II), comprising 16 and 13 transitions respectively, have been described for {sup 147}Gd nucleus during the {sup 122}Sn({sup 30}Si,5n) fusion-evaporation reaction in a 155 MeV bombardment energy. Dynamic inertia momentum similarities and gamma transition energy similarities have been observed between band I and {sup 148}Gd nucleus and between band II and {sup 146}Gd nucleus, respectively. These similarities can be related to a pseudo-spin symmetry. Calculations suggest the existence of an octupolar susceptibility in this mass region. {sup 144}Gd nucleus has been studied using {sup 120}Sn({sup 29}Si,5n) fusion-evaporation reaction in a 155 MeV bombardment energy and using {sup 100}Mo({sup 48}Ti,4n) reactions in a 200 MeV bombardment energy. {gamma}-{gamma} coincidences have revealed the existence of a 58 keV width valley in the matrix representation compatible with theoretical predictions. In spite of the evidence for about ten transitions during these experiments, no superdeformed structure has been demonstrated for {sup 144}Gd nucleus. (J.S.). 87 refs., 57 figs., 41 tabs.

Nuclear moments of inertia and wobbling motions in triaxial superdeformed nuclei

International Nuclear Information System (INIS)

Matsuzaki, Masayuki; Shimizu, Yoshifumi R.; Matsuyanagi, Kenichi

2004-01-01

The wobbling motion excited on triaxial superdeformed nuclei is studied in terms of the cranked shell model plus random phase approximation. First, by calculating at a low rotational frequency the γ dependence of the three moments of inertia associated with the wobbling motion, the mechanism of the appearance of the wobbling motion in positive-γ nuclei is clarified theoretically--the rotational alignment of the πi 13/2 quasiparticle(s) is the essential condition. This indicates that the wobbling motion is a collective motion that is sensitive to the single-particle alignment. Second, we prove that the observed unexpected rotational-frequency dependence of the wobbling frequency is an outcome of the rotational-frequency dependent dynamical moments of inertia

Collectivity of high spin states in {sup 84}Zr

Energy Technology Data Exchange (ETDEWEB)

Lister, C.J.; Blumenthal, D.; Crowell, B. [and others

1995-08-01

{sup 84}Zr is one of the most extensively studied of the A {approximately} 80 rotors, both from theoretical and experimental approaches. It was predicted to be a good candidate to support superdeformation, and to show interesting spectroscopic properties including saturation of its shell-model space at lower spin. We performed an experiment using Gammasphere in its early implementation phase. The reaction of {sup 29}Si on {sup 58}Ni was used to strongly populate {sup 84}Zr at high spin. Thin and thick targets were used to allow the extraction of transitional matrix elements at very high spin, and to allow a sensitive search for superdeformed states. Data analysis is in progress. The large data set allowed us to extend the previously known bands considerably. Candidates for a staggered M1-band, found previously {sup 86}Zr, were located. To date, no evidence for superdeformed bands was found. Analysis was slowed by the relocation of all the participants in this experiment, but we hope to complete the lifetime analysis this year. This analysis has become especially topical, due to reported measurements of superdeformation in this region.

Microscopic study of superdeformation in the A = 150 mass region

Energy Technology Data Exchange (ETDEWEB)

Rigollet, C.; Gall, B. [CNRS, Strasbourg (France); Bonche, P. [CEN Saclay, Gif sur Yvette (France)] [and others

1996-12-31

The authors are presently investigating the properties of superdeformed (SD) nuclear states in the A=150 mass region. For that purpose, they use the cranked HFB method in which pairing correlations are treated dynamically by means of the Lipkin-Nogami prescription. Their goal is to take advantage of the large amount of experimental data to test the predictive power of their microscopic approach and of the effective interaction. In the present communication, they focus on {sup 152}Dy and {sup 153}Dy for which there are recent experimental data. In particular lifetime measurements have allowed to extract electric quadrupole moments. The new Skyrme effective force SLy4 is used to describe the nucleon-nucleon interaction, while for the pairing channel the authors use a density-dependent zero-range interaction.

Clustering aspects of sd shell nuclei studied by AMD

International Nuclear Information System (INIS)

Kimura, Masaaki; Taniguchi, Yasutaka; En'yo, Yoshiko; Horiuchi, Hisashi

2006-01-01

The new clustering aspects of sd-shell nuclei found by the recent application of the antisymmetrized molecular dynamics are reported. In this paper we present two topics, 'superdeformed band of 32 S and 16 O + 16 O clustering' and 'molecular-orbital and di-nuclei states in 22 Ne'. In the first topic, it will be shown that the superdeformed band of 32S has a considerable amount of 16 O + 16 O cluster component, and can be regarded as to belong to a family of the 16 O + 16 O molecular bands. In the second topic, the presence of the molecularorbital band which has an α + 16 O cluster core surrounded by two covalently neutrons is suggested together with an α + 18 O di-nuclei band

Study of nano - second isomers near 146Gd

International Nuclear Information System (INIS)

Pramanik, Dibyadyuti; Sarkar, S.; Bisoi, Abhijit; Ray, Sudatta; Ray, I.; Pradhan, M.K.; Goswami, A.; Banerjee, P.; Mukherjee, A.; Bhattacharya, S.; Saha Sarkar, M.; Chakraborty, A.; Dey, Gautam; Krishichayan; Kshetri, R.; Ganguly, S.; Raut, R.; Ray Basu, M.; Ganguly, G.; Ghugre, S.S.; Sinha, A.K.; Basu, S.K.

2010-01-01

The nuclei near 146 Gd show rich variety in their excitation spectra. Spectra exhibiting characteristics of extreme single particle, multi-particle-hole excitation, magnetic bands to strong collectivity manifested through superdeformation, and triaxial superdeformation have been widely studied. In the present work, a few isomers in the mass ≅150 region using the RF - gamma coincidence data are studied

Electrodynamics of an omega-band as deduced from optical and magnetometer data

Directory of Open Access Journals (Sweden)

H. Vanhamäki

2009-09-01

Full Text Available We investigate an omega-band event that took place above northern Scandinavia around 02:00–02:30 UT on 9 March 1999. In our analysis we use ground based magnetometer, optical and riometer measurements together with satellite based optical images. The optical and riometer data are used to estimate the ionospheric Hall and Pedersen conductances, while ionospheric equivalent currents are obtained from the magnetometer measurements. These data sets are used as input in a local KRM calculation, which gives the ionospheric potential electric field as output, thus giving us a complete picture of the ionospheric electrodynamic state during the omega-band event. The overall structure of the electric field and field-aligned current (FAC provided by the local KRM method are in good agreement with previous studies. Also the E×B drift velocity calculated from the local KRM solution is in good qualitative agreement with the plasma velocity measured by the Finnish CUTLASS radar, giving further support for the new local KRM method. The high-resolution conductance estimates allow us to discern the detailed structure of the omega-band current system. The highest Hall and Pedersen conductances, ~50 and ~25 S, respectively, are found at the edges of the bright auroral tongue. Inside the tongue, conductances are somewhat smaller, but still significantly higher than typical background values. The electric field shows a converging pattern around the tongues, and the field strength drops from ~40 mV/m found at optically dark regions to ~10 mV/m inside the areas of enhanced conductivity. Downward FAC flow in the dark regions, while upward currents flow inside the auroral tongue. Additionally, sharp conductance gradients at the edge of an auroral tongue are associated with narrow strips of intense FACs, so that a strip of downward current flows at the eastern (leading edge and a similar strip of upward current is present at the western (trailing edge. The Joule

α-clustering and triaxial deformations in 40Ca

International Nuclear Information System (INIS)

Taniguchi, Yasutaka; Kimura, Masaaki; Kanada-En'yo, Yoshiko; Horiuchi, Hisashi

2007-01-01

We have studied the positive-parity states of 40 Ca using antisymmetrized molecular dynamics (AMD) and the generator coordinate method (GCM). Imposing two different kinds of constraints on the variational calculation, we have found various kinds of 40 Ca structures such as a deformed-shell structure, as well as α- 36 Ar and 12 C- 28 Si cluster structures. After the GCM calculation, we obtained a normal-deformed band and a superdeformed band together with their side bands associated with triaxial deformation. The calculated B(E2) values agreed well with empirical data. It was also found that the normal-deformed and superdeformed bands contain α- 36 Ar and 12 C- 28 Si cluster structure components, respectively. This leads to the presence of an α- 36 Ar higher-nodal band occurring above the normal-deformed band

Clustering and triaxial deformations of 40Ca

International Nuclear Information System (INIS)

Taniguchi, Yasutaka; Kimura, Masaaki; Kanada-En'yo, Yoshiko; Horiuchi, Hisashi

2007-01-01

We have studied the positive-parity states of 40 Ca using antisymmetrized molecular dynamics (AMD) and the generator coordinate method (GCM). Imposing two different kinds of constraints on the variational calculation, we have found various kinds of 40 Ca structures such as a deformed-shell structure, as well as α- 36 Ar and 12 C- 28 Si cluster structures. After the GCM calculation, we obtained a normal-deformed band and a superdeformed band together with their side bands associated with triaxial deformation. The calculated B(E2) values agreed well with empirical data. It was also found that the normal-deformed and superdeformed bands have non-negligible α- 36 Ar cluster and 12 C- 28 Si cluster components, respectively. This leads to the presence of an α- 36 Ar higher nodal band occurring above the normal-deformed band

Deducing magnetic resonance neuroimages based on knowledge from samples.

Science.gov (United States)

Jiang, Yuwei; Liu, Feng; Fan, Mingxia; Li, Xuzhou; Zhao, Zhiyong; Zeng, Zhaoling; Wang, Yi; Xu, Dongrong

2017-12-01

Because individual variance always exists, using the same set of predetermined parameters for magnetic resonance imaging (MRI) may not be exactly suitable for each participant. We propose a knowledge-based method that can repair MRI data of undesired contrast as if a new scan were acquired using imaging parameters that had been individually optimized. The method employed a strategy called analogical reasoning to deduce voxel-wise relaxation properties using morphological and biological similarity. The proposed framework involves steps of intensity normalization, tissue segmentation, relaxation time deducing, and image deducing. This approach has been preliminarily validated using conventional MRI data at 3T from several examples, including 5 normal and 9 clinical datasets. It can effectively improve the contrast of real MRI data by deducing imaging data using optimized imaging parameters based on deduced relaxation properties. The statistics of deduced images shows a high correlation with real data that were actually collected using the same set of imaging parameters. The proposed method of deducing MRI data using knowledge of relaxation times alternatively provides a way of repairing MRI data of less optimal contrast. The method is also capable of optimizing an MRI protocol for individual participants, thereby realizing personalized MR imaging. Copyright © 2017 Elsevier Ltd. All rights reserved.

Clustering aspects of sd shell nuclei studied by AMD

Energy Technology Data Exchange (ETDEWEB)

Kimura, Masaaki [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Taniguchi, Yasutaka [Department of Physics, Kyoto University, Kitashirakawa, Kyoto 606-8502 (Japan); En' yo, Yoshiko [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Horiuchi, Hisashi [Department of Physics, Kyoto University, Kitashirakawa, Kyoto 606-8502 (Japan)

2006-10-10

The new clustering aspects of sd-shell nuclei found by the recent application of the antisymmetrized molecular dynamics are reported. In this paper we present two topics, 'superdeformed band of {sup 32}S and {sup 16}O + {sup 16}O clustering' and 'molecular-orbital and di-nuclei states in {sup 22}Ne'. In the first topic, it will be shown that the superdeformed band of 32S has a considerable amount of {sup 16}O + {sup 16}O cluster component, and can be regarded as to belong to a family of the {sup 16}O + {sup 16}O molecular bands. In the second topic, the presence of the molecularorbital band which has an {alpha} + {sup 16}O cluster core surrounded by two covalently neutrons is suggested together with an {alpha} + {sup 18}O di-nuclei band.

Electronic structure of SnS deduced from photoelectron spectra and band-structure calculations

NARCIS (Netherlands)

Ettema, A.R.H.F.; Groot, R.A. de; Haas, C.; Turner, T.S.

1992-01-01

SnS is a layer compound with a phase transition from a high-temperature β phase to a low-temperature α phase with a lower symmetry. Ab initio band-structure calculations are presented for both phases. The calculations show that the charge distributions in the two phases are very similar. However,

Calculation of the spectrum of {gamma} rays connecting superdeformed and normally deformed nuclear states

Energy Technology Data Exchange (ETDEWEB)

Dossing, T.; Khoo, T.L.; Lauritsen, T. [and others

1995-08-01

The decay out of superdeformed states occurs by coupling to compound nuclear states of normal deformation. The coupling is very weak, resulting in mixing of the SD state with one or two normal compound states. With a high energy available for decay, a statistical spectrum ensues. The shape of this statistical spectrum contains information on the level densities of the excited states below the SD level. The level densities are sensitively affected by the pair correlations. Thus decay-out of a SD state (which presents us with a means to start a statistical cascade from a highly-excited sharp state) provides a method for investigating the reduction of pairing with increasing thermal excitation energy.

Experimental study of ΔI=1 bands in In111

Science.gov (United States)

Banerjee, P.; Ganguly, S.; Pradhan, M. K.; Sharma, H. P.; Muralithar, S.; Singh, R. P.; Bhowmik, R. K.

2011-02-01

The two ΔI=1 bands in In111, built upon the 3461.0 and 4931.8 keV states, have been studied. The bands were populated in the reaction Mo100(F19,α4nγ) at a beam energy of 105 MeV. Mean lifetimes of nine states, four in the first and five in the second band, have been determined for the first time from Doppler shift attenuation data. The deduced B(M1) rates and their behavior as a function of level spin support the interpretation of these bands within the framework of the shears mechanism. The geometrical model of Machiavelli has been used to derive the effective gyromagnetic ratios for the two bands.

Shape isomers: Mean-field description and beyond

International Nuclear Information System (INIS)

Bonche, P.; Krieger, S.J.; Weiss, M.S.; Dobaczewski, J.; Meyer, J.

1990-01-01

Nuclear Hartree-Fock (HF) + BCS calculations have led to predictions of shape isomerism in isotopes of Pt, Hg and Os nuclei. These have been confirmed through the observation of superdeformed rotational bands in 190,hor-ellipsis,194 Hg. Encouraged by these measurements and similar observations in 194 Pb, we have extended these calculations to a wide range of contiguous nuclei. These HF results, for 192,194 Pt, 190,hor-ellipsis,198 Hg and 194 Pb, have been employed in a Generator Coordinate Method (GCM) calculation utilizing the quadrupole deformation as the generating variable. The resulting spectra confirm the conclusions drawn from the HF results and agree with those experiments which have been performed. Adding a phenomenological assumption for the moments of inertia of our GCM states, we can construct the radiative transitions within and out of the superdeformed band. The results are in good agreement with the observed de-population of the superdeformed band built upon the shape isomer both in minimum angular momentum and in rapidity of de-population. Inferences for the existence of shape isomers will be drawn. 19 refs., 4 figs

Gamma decay and band structures in 46Ti

International Nuclear Information System (INIS)

Dracoulis, G.D.; Radford, D.C.; Poletti, A.R.

1978-03-01

The states of 46 Ti have been studied using the 43 Ca(α,nγ) reaction. The level and decay scheme of 46 Ti was deduced from γ-γ coincidence, γ-ray energy and intensity measurements. Spins are suggested on the basis of the γ-ray angular distribution, supported by relative excitation functions. The ground state band has been extended to spin 10 + , and about 20 new states are observed. Some of these can be grouped into rotational-like bands based on the 3 - state at 3.059 MeV and other excited states

γ-spectroscopy of the superdeformed 240mPu with the CLUSTER-CUBE

International Nuclear Information System (INIS)

Pansegrau, D.; Ender, C.; Haertlein, T.; Koeck, F.; Reiter, P.; Schwalm, D.; Eberth, J.; Thomas, H.G.

1997-01-01

The study of γ-decays of excited states in the second minimum of the double-humped fission barrier in actinides can make a substantial contribution towards a better understanding of the structure of superdeformed nuclei. An experiment using the EUROBALL-CLUSTER-CUBE was performed to observe these extremely rare γ-decays. The 238 U(α, 2n)-reaction was selected to populate the shape isomer 240m Pu, which decays via delayed fission with a half life of 3.8 ns. The delayed fission enables an unambiguous trigger on the population of the shape isomer. Prompt γ-decays of excited states in the second minimum were detected in coincidence with delayed fission fragments. A strong transition at 786 keV, which shows an isotropic angular distribution, and some weaker transitions in the region of 550 keV and 820 keV could be observed. (orig.)

Experimental study of ΔI=1 bands in 111In

International Nuclear Information System (INIS)

Banerjee, P.; Pradhan, M. K.; Ganguly, S.; Sharma, H. P.; Muralithar, S.; Singh, R. P.; Bhowmik, R. K.

2011-01-01

The two ΔI=1 bands in 111 In, built upon the 3461.0 and 4931.8 keV states, have been studied. The bands were populated in the reaction 100 Mo( 19 F, α4nγ) at a beam energy of 105 MeV. Mean lifetimes of nine states, four in the first and five in the second band, have been determined for the first time from Doppler shift attenuation data. The deduced B(M1) rates and their behavior as a function of level spin support the interpretation of these bands within the framework of the shears mechanism. The geometrical model of Machiavelli et al. has been used to derive the effective gyromagnetic ratios for the two bands.

Shell model for warm rotating nuclei

Energy Technology Data Exchange (ETDEWEB)

Matsuo, M.; Yoshida, K. [Kyoto Univ. (Japan); Dossing, T. [Univ. of Copenhagen (Denmark)] [and others

1996-12-31

Utilizing a shell model which combines the cranked Nilsson mean-field and the residual surface and volume delta two-body forces, the authors discuss the onset of rotational damping in normal- and super-deformed nuclei. Calculation for a typical normal deformed nucleus {sup 168}Yb indicates that the rotational damping sets in at around 0.8 MeV above the yrast line, and about 30 rotational bands of various length exists at a given rotational frequency, in overall agreement with experimental findings. It is predicted that the onset of rotational damping changes significantly in different superdeformed nuclei due to the variety of the shell gaps and single-particle orbits associated with the superdeformed mean-field.

Evidences for magicity in superdeformed shapes

Indian Academy of Sciences (India)

inertia (0) and nuclear softness parameter (σ) for the SD bands in all the mass regions ... to a good understanding of the observed SD bands and fission isomers. .... to the positions of least level density, we expect the. SD bands near magic nucleon numbers to be more close to exact rigid rotor. The usual. 30 40. 50. 60. 70.

Tunneling from super- to normal-deformed minima in nuclei

International Nuclear Information System (INIS)

Khoo, T. L.

1998-01-01

An excited minimum, or false vacuum, gives rise to a highly elongated superdeformed (SD) nucleus. A brief review of superdeformation is given, with emphasis on the tunneling from the false to the true vacuum, which occurs in the feeding and decay of SD bands. During the feeding process the tunneling is between hot states, while in the decay it is from a cold to a hot state. The γ spectra connecting SD and normal-deformed (ND) states provide information on several physics issues: the decay mechanism; the spin/parity quantum numbers, energies and microscopic structures of SD bands; the origin of identical SD bands; the quenching of pairing with excitation energy; and the chaoticity of excited ND states at 2.5-5 MeV. Other examples of tunneling in nuclei, which are briefly described, include the possible role of tunneling in ΔI = 4 bifurcation in SD bands, sub-barrier fusion and proton emitters

Tunneling from super- to normal-deformed minima in nuclei.

Energy Technology Data Exchange (ETDEWEB)

Khoo, T. L.

1998-01-08

An excited minimum, or false vacuum, gives rise to a highly elongated superdeformed (SD) nucleus. A brief review of superdeformation is given, with emphasis on the tunneling from the false to the true vacuum, which occurs in the feeding and decay of SD bands. During the feeding process the tunneling is between hot states, while in the decay it is from a cold to a hot state. The {gamma} spectra connecting SD and normal-deformed (ND) states provide information on several physics issues: the decay mechanism; the spin/parity quantum numbers, energies and microscopic structures of SD bands; the origin of identical SD bands; the quenching of pairing with excitation energy; and the chaoticity of excited ND states at 2.5-5 MeV. Other examples of tunneling in nuclei, which are briefly described, include the possible role of tunneling in {Delta}I = 4 bifurcation in SD bands, sub-barrier fusion and proton emitters.

The study of very high spin states

International Nuclear Information System (INIS)

Nolan, P.J.

1992-01-01

Some examples are given of the study of very high spin states that decay by discrete line gamma-ray emission. States up to spin 70(h/2π) have been seen in superdeformed bands. In other bands with normal deformation the limit is near 50(h/2π). (Author)

Physics-based Inverse Problem to Deduce Marine Atmospheric Boundary Layer Parameters

Science.gov (United States)

2017-03-07

knowledge and capabilities in the use and development of inverse problem techniques to deduce atmospheric parameters. WORK COMPLETED The research completed...please find the Final Technical Report with SF 298 for Dr. Erin E. Hackett’s ONR grant entitled Physics -based Inverse Problem to Deduce Marine...From- To) 07/03/2017 Final Technica l Dec 2012- Dec 2016 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Physics -based Inverse Problem to Deduce Marine

Resolution of the 179W-isomer anomaly: Exposure of a Fermi-aligned s band

International Nuclear Information System (INIS)

Walker, P.M.; Dracoulis, G.D.; Byrne, A.P.; Fabricius, B.; Kibedi, T.; Stuchbery, A.E.; Department of Physics, University of Surrey, Guildford, GU2 5XH United Kingdom)

1991-01-01

The K π =35/2 - , five-quasiparticle isomer in 179 W is shown to decay into the region of a backbend in the 7/2 - [514] band, allowing for the first time the identification of a full set of aligned-band states. Destructive interference results from level mixing in the band-crossing region. The deduced γ-ray branching ratios are used to establish the mixing matrix elements and to show that the aligned band has a high value of the K quantum number. The properties of well-defined alignment and yet also high K provide the first clear example of a Fermi-aligned s band. The anomalous decay of the isomer itself is now explained

Generalized seniority scheme for bands in odd-A nuclei

International Nuclear Information System (INIS)

Gai, M.; Arima, A.; Strottman, D.

1980-01-01

The microscopic generalized seniority scheme is applied for the description of bands in odd-A nuclei. A perturbation expansion in terms of the core-particle interaction is performed. The first-order correction for the band head and the first member of the band is discussed. The specific band structure of a given nucleus, as well as the systematic trend of bands, is described in an explicit N-dependent analytical formula. This formula involves a linear dependence on N which arises from the first-order perturbation expansion. This term is shown responsible for the large deviation of the 11/2 - ΔJ=2 band spacing in I isotopes from the spacing of the Te core. All observed band structures of an odd-A nucleus arise from one simple core-particle coupling. Hence decoupled-E2 bands and strongly coupled ΔJ=1 bands, particle or hole bands of low-spin or high-spin orbits, all follow one simple N-dependence. This uniformity of bands is manifested in E2 bands in 53 I isotopes and deltaJ=1 bands in 51 Sb that have the same 52 Te cores. For the calculations a particle-particle force with a large contribution from a g delta force is used with a coupling constant that is deduced from 210 Pb. 1 figure

Investigation of high spin structure of N ∼ 28 nuclei with PHF model

International Nuclear Information System (INIS)

Naik, Z.

2016-01-01

Nucleus in 50 mass shows verity of high spin phenomena. Some of them are K-Isomer, Band termination, States Beyond Band termination, Superdeformed Structure, Shape co-existence and many more. Some of these phenomena with Projected Hartree-Fock (PHF) model are addressed and the microscopic structure associate with them is discussed

Simulation of the Band Structure of Graphene and Carbon Nanotube

International Nuclear Information System (INIS)

Mina, Aziz N; Awadallah, Attia A; Ahmed, Riham R; Phillips, Adel H

2012-01-01

Simulation technique has been performed to simulate the band structure of both graphene and carbon nanotube. Accordingly, the dispersion relations for graphene and carbon nanotube are deduced analytically, using the tight binding model and LCAO scheme. The results from the simulation of the dispersion relation of both graphene and carbon nanotube were found to be consistent with those in the literature which indicates the correctness of the process of simulation technique. The present research is very important for tailoring graphene and carbon nanotube with specific band structure, in order to satisfy the required electronic properties of them.

A particle-number conserving microscopic approach to octupole deformation of normal deformed and superdeformed states in 194Pb

International Nuclear Information System (INIS)

Nhan Hao, T.V.; Phu Dat, D.H.; Hoang Tung, N.; Tran, H.N.

2015-01-01

The left–right asymmetric deformation of normal deformed (ND) and superdeformed (SD) states of 194 Pb has been investigated in the framework of the parity-symmetry projection of the highly truncated diagonalization approach (HTDA), which is suited to treat the correlations in an explicitly particle-number conserving microscopic approach. A Skyrme energy density functional using the SIII and SkM* interactions has been considered to treat the particle–hole channel, whereas a density-independent δ force has been adopted for the residual interaction. The obtained results are compared with previous approaches. The calculated octupole phonon excitation energy is found to be in good qualitative agreement with available data in the ND state. (author)

Resolution of the 179W isomer anomaly: exposure of a fermi aligned s-band

International Nuclear Information System (INIS)

Walker, P.M.; Surrey Univ., Guildford; Dracoulis, G.D.; Byrne, A.P.; Fabricius, B.; Kibedi, T.; Stuchbery, A.E.

1991-06-01

The K Π = 35/2 - , five quasiparticle isomer in 179 W is shown to decay into the region of a backbend in the 7/2 - [514] band, allowing for the first time the identification of a full set of aligned-band states. Destructive interference results from level-mixing in the band-crossing region. The deduced γ-ray branching ratios are used to establish the mixing matrix elements and to show that the aligned band has a high value of the K-quantum number. The properties of well-defined alignment and yet also high-K, provided the first clear example of a Fermi Aligned s-band. The anomalous decay of the isomer itself is now explained. 11 refs., 1 tab., 3 figs

Change of deformation at the backbending in the yrast superdeformed band of {sup 144}Gd

Energy Technology Data Exchange (ETDEWEB)

Ur, C.A.; Bolzonella, G.P.; Bazzacco, D. [dell`Universita, Padova (Italy)]|[INFN, Padova (Italy)] [and others

1996-12-31

A mean lifetime measurement using the Doppler shift attenuation method has been performed at GASP in order to extract the quadrupole moment of the yrast SD band of {sup 144}Gd. The extracted intrinsic quadrupole moments, being Q{sub 0}=13.7 eb above the backbending and Q{sub 0}=11.8 eb below the backbending, are consistent with a change of deformation from {beta}{sub 2}=0.51 (at {beta}{sub 4} {approx} 0.050) to {beta}{sub 2}=0.45 (at {beta}{sub 4} {approx}0.035). The experimental results are in nice agreement with the theoretical predictions, which revealed that the second well in {sup 144}Gd arises essentially from the very favored shell structure at N=80 and Z=64. The occupation at higher frequency of the aligned N=6 proton orbitals drives the nucleus to a slightly more deformed shape.

Study of the strength distribution of primary γ-transitions in the decay from superdeformed states in 194Hg

International Nuclear Information System (INIS)

Lopez-Martens, A.P.; Doessing, T.; Khoo, T.L.; Korichi, A.; Hannachi, F.; Calderin, I.J.; Lauritsen, T.; Ahmad, I.; Carpenter, M.P.; Fischer, S.M.; Hackman, G.; Janssens, R.V.F.; Nisius, D.; Reiter, P.; Amro, H.; Moore, E.F.

1999-01-01

The strength distribution of the primary γ rays in the decay from superdeformed (SD) states is investigated by applying the maximum likelihood method. For the 194 Hg nucleus, 41 primary transitions are identified above 2600 keV. It is concluded that they represent the strongest 10% of the transitions selected stochastically from a Porter-Thomas distribution. This would support the scenario of a statistical decay of SD states via coupling to a compound state at normal deformation. However, the occurrence of several very strong 'one-step linking' transitions is found to have a very small probability. Based on the absence of strong primary transitions from SD states in adjacent nuclei, the situation in 194 Hg is viewed as a very lucky incidence

The highest spin discrete levels in 131,132Ce

International Nuclear Information System (INIS)

Paul, E S; Choy, P T W; Andreoiu, C; Boston, A J; Evans, A O; Fox, C; Gros, S; Nolan, P J; Rainovski, G; Sampson, J A; Scraggs, H C; Walker, A; Appelbe, D E; Joss, D T; Simpson, J; Gizon, J; Astier, A; Buforn, N; Prevost, A; Redon, N; Stezowski, O; Nyako, B M; Sohler, D; Timar, J; Zolnai, L; Bazzacco, D; Lunardi, S; Petrache, C M; Bednarczyk, P; Curien, D; Kintz, N; Ragnarsson, I

2006-01-01

The three superdeformed (SD) bands in 132 Ce and the two SD bands in 131 Ce have been extended to higher spin following experiments with the EUROBALL IV spectrometer. The two SD bands in 131 Ce have been linked together. However, despite the relatively high population intensity of the bands (up to 5% of the respective channel), it has not been possible to unambiguously link any of the five SD bands into the low-spin, normally deformed structures of 131,132 Ce

Tracking intruder states

Energy Technology Data Exchange (ETDEWEB)

Riedinger, L L; Mueller, W F; Yu, C H [Tennessee Univ., Knoxville, TN (United States). Dept. of Physics

1992-08-01

The deformation-driving effects of intruder states are studied by analysis of various types of data on rotational bands in rare-earth deformed nuclei. The sensitivity of four measurables (bandhead energy, B(E2) value, neutron i{sub 13/2} crossing frequency, and signature splitting) to increased deformation in an intruder band is shown. The analysis of signature splitting systematics is extended to known superdeformed bands. (author). 22 refs., 5 figs.

Effect of clear bands on intergranular stresses and IASCC early damage - 04002

International Nuclear Information System (INIS)

Sauzay, M.; Ould Moussa, M.; Diawara, B.; Lebreau, F.

2016-01-01

Slip localization is a common feature in post-irradiated metallic poly-crystals undergoing tensile straining. This effect takes place for instance in the form of thin slip bands called channels or clear bands, formed after the local vanishing of irradiation defects induced interactions with gliding dislocations. Channel impingement towards grain boundaries (GBs) should induce local stress concentrations along GBs, in the quasi-elastic surrounding matrix. It has been shown extensively that this trigger GB crack initiation. Grain boundary fracture is simulated using a double criterion based on both critical normal stress and fracture energy as deduced from atomistic computations of GB fracture. The critical stress is deduced from the fracture energy using the universal-binding-energy relationship (UBER). In the case of brittle fracture, the fracture energy is defined as the two fresh free surface energy values minus the GB energy. In relationship with the more complex topic of irradiation induced stress corrosion cracking (IASCC) occurring in-service conditions, the influence of irradiation dose, strain rate and irradiation creep is discussed. Due to the complex loading history highlighted by structural finite element analysis, strain peaks may induce the formation of clear bands or twin bands. The study of the effect of irradiation creep on the relaxation of the induced GB stress fields shows clearly that the relaxation requires many months due to the linear irradiation creep law. Such durations allows GB oxidation mechanisms to occur leading to a weakening of the GB fracture parameters in the vicinity of the free surfaces. This short paper is followed by the slides of the presentation

Valence band offset of wurtzite InN/SrTiO3 heterojunction measured by x-ray photoelectron spectroscopy

Directory of Open Access Journals (Sweden)

Li Zhiwei

2011-01-01

Full Text Available Abstract The valence band offset (VBO of wurtzite indium nitride/strontium titanate (InN/SrTiO3 heterojunction has been directly measured by x-ray photoelectron spectroscopy. The VBO is determined to be 1.26 ± 0.23 eV and the conduction band offset is deduced to be 1.30 ± 0.23 eV, indicating the heterojunction has a type-I band alignment. The accurate determination of the valence and conduction band offsets paves a way to the applications of integrating InN with the functional oxide SrTiO3.

[Auditory training with wide-band white noise: effects on the recruitment (III)].

Science.gov (United States)

Domínguez Ugidos, L J; Rodríguez Morejón, C; Vallés Varela, H; Iparraguirre Bolinaga, V; Knaster del Olmo, J

2001-05-01

The auditory training with wide-band white noise is a methodology for the qualitative recovery of the hearing loss in people suffering from sensorineural hearing loss. It is based on the application of a wide-band white modified noise. In a prospective study, we have assessed the modifications of the recruitment coefficient in a sample of 48 patients who have followed a program of 15 auditory training with wide-band white noise sessions. The average improvement of the recruitment coefficient expressed in percentage is a 7.7498%, which comes up to 23.5249% in the case of a binaural recruitment coefficient. From our results, it can be deduced that the auditory training with wide-band white noise reduces the recruitment. That is to say, the decrease of the recruitment in high intensities both binaurally and in all ears.

Lifetimes near the bandhead of a shears band in 198Pb

International Nuclear Information System (INIS)

Kruecken, R.; Kruecken, R.; Clark, R.M.; Deleplanque, M.A.; Diamond, R.M.; Fallon, P.; Lee, I.Y.; Macchiavelli, A.O.; Schmid, G.J.; Stephens, F.S.; Vetter, K.; Dewald, A.; Peusquens, R.; Brentano, P. von; Hauschild, K.

1998-01-01

Subpicosecond lifetimes of states near the bandhead of an M1 band in 198 Pb have been measured with the recoil-distance Doppler-shift technique using the Gammasphere array and the Cologne plunger. The deduced B(M1) values are in agreement with the predictions of the tilted axis cranking (TAC) model. Their spin dependence continues the trend set by recently published B(M1) values for the high spin states in this band. The emerging picture gives strong support to the concept of open-quotes magnetic rotation,close quotes an alternative mode for the generation of rotational spectra in nuclei. copyright 1998 The American Physical Society

Triaxiality and the wobbling mode In 167Lu

International Nuclear Information System (INIS)

Amro, H.; Ma, W.C.; Winger, J.A.; Li, Y.; Thompson, J.; Hagemann, G.; Herskind, B.; Sletten, G.; Wilson, J.N.; Jensen, D.R.; Fallon, P.; Ward, D.; Diamond, R.M.; Goergen, A.; Machiavelli, A.; Huebel, H.; Domscheit, J.; Wiedenhoewer, I.

2002-01-01

High spin states in 167Lu nucleus were populated through the 123Sb(48Ca,xn) reaction at 203 MeV. Five presumably triaxial superdeformed (TSD) bands have been found. The electromagnetic properties of several connecting transitions between the yrast (TSD1) and the excited (TSD2) bands have been established. Evidence for the assignment of TSD2 band as a wobbling mode built on the yrast TSD band is presented. These bands coexist with bands built on quasiparticle excitations in normal deformed (ND) minimum for which new data are also presented

ELECTRONIC-STRUCTURE OF THE MISFIT-LAYER COMPOUND (SNS)(1.17)NBS2 DEDUCED FROM BAND-STRUCTURE CALCULATIONS AND PHOTOELECTRON-SPECTRA

NARCIS (Netherlands)

FANG, CM; ETTEMA, ARHF; HAAS, C; WIEGERS, GA; VANLEUKEN, H; DEGROOT, RA

1995-01-01

In order to understand the electronic structure of the misfit-layer compound (SnS)(1.17)NbS2 we carried out an ab initio band-structure calculation of the closely related commensurate compound (SnS)(1.20)NbS2. The band structure is compared with calculations for NbS2 and for hypothetical SnS with

High-spin structure of 121Xe: triaxiality, band termination and signature inversion

International Nuclear Information System (INIS)

Timar, J.; Paul, E.S.; Beausang, C.W.; Joyce, M.J.; Sharpey-Schafer, J.F.

1995-01-01

High-spin states of the odd-neutron 121 Xe nucleus have been studied with Eurogam using the 96 Zr( 30 Si, 5n) 121 Xe fusion-evaporation reaction. The level scheme has been extended up to a tentative spin of 67/2h at an excitation energy of ∼ 14 MeV. Several new rotational bands have been observed and the previously known bands extended. Two of them lose their regular character at high spins, which may be interpreted as transition from collective behaviour to a regime of noncollective oblate states. The deduced high-spin structure is compared to Woods-Saxon TRS cranking and CSM calculations. Configurations of the bands have been suggested. The νh 1 1/2 band is interpreted as having a triaxial shape. Signature inversion and an unexpectedly large staggering of the B(M1)/B(E2) ratios has been found for one of the bands. Enhanced E1 transitions have been observed between the νd 5/2 and the νh 1 1/2 bands. (orig.)

Evidence of the wobbling mode

International Nuclear Information System (INIS)

Odegaard, S.W.; Tjoem, P.O.; Hagemann, G.B.; Jensen, D.R.; Bergstroem, M.; Herskind, B.; Sletten, G.; Toermaenen, S.; Wilson, J.N.; Hamamoto, I.; Spohr, K.; Huebel, H.; Goergen, A.; Schoenwasser, G.; Bracco, A.; Leoni, S.; Maj, A.; Petrache, C.M.; Bednarczyk, P.; Curien, D.

2002-01-01

The wobbling mode is a direct consequence of rotational motion of a triaxial body. The wobbling degree of freedom introduces sequences of bands with increasing number of wobbling quanta and a characteristic ΔI=1 decay pattern between the bands in competition with the in-band decay. A favorable candidate for establishing this exotic excitation mode is found for the first time in one of the Lu-isotopes for which stable triaxial superdeformed shapes are expected

Direct imaging of band profile in single layer MoS2 on graphite: quasiparticle energy gap, metallic edge states, and edge band bending.

Science.gov (United States)

Zhang, Chendong; Johnson, Amber; Hsu, Chang-Lung; Li, Lain-Jong; Shih, Chih-Kang

2014-05-14

Using scanning tunneling microscopy and spectroscopy, we probe the electronic structures of single layer MoS2 on graphite. The apparent quasiparticle energy gap of single layer MoS2 is measured to be 2.15 ± 0.06 eV at 77 K, albeit a higher second conduction band threshold at 0.2 eV above the apparent conduction band minimum is also observed. Combining it with photoluminescence studies, we deduce an exciton binding energy of 0.22 ± 0.1 eV (or 0.42 eV if the second threshold is use), a value that is lower than current theoretical predictions. Consistent with theoretical predictions, we directly observe metallic edge states of single layer MoS2. In the bulk region of MoS2, the Fermi level is located at 1.8 eV above the valence band maximum, possibly due to the formation of a graphite/MoS2 heterojunction. At the edge, however, we observe an upward band bending of 0.6 eV within a short depletion length of about 5 nm, analogous to the phenomena of Fermi level pinning of a 3D semiconductor by metallic surface states.

Coupling constants deduced for the resonances in kaon photo-production

International Nuclear Information System (INIS)

Cheoun, M. K.; Kim, K. S.; Choi, T. K.

2004-01-01

We deduced the coupling constants of nucleon and hyperon resonances, which participate in kaon productions as intermediate states that are formed by electro-magnetic probes and that finally decay into hadronic final states. We used an isobaric model based on an effective Lagrangian approach to describe the processes, in which relevant coupling constants regarding related resonances are effectively determined by fitting available experimental data. Our scheme to deduce the coupling constants was as follows: First, we calculated the lower and the upper limits on the coupling constants by using the experimental decay data available until now and/or theoretical predictions, such as those from quark models and SU(3) symmetry. Second, we exploited those limits as physical constraints on our fitting scheme for the kaon photo-production data. Finally, the deduced values and regions of the coupling constants, which satisfy not only the reaction data but also the decay data, are presented as figures with respect to the strong and the electro-magnetic coupling constants, and their multiplicative values. Our results for the coupling constants give physical values that are more restricted than those allowed by the experimental data nowadays.

Band structure in 83Rb from lifetime measurements

International Nuclear Information System (INIS)

Ganguly, S.; Banerjee, P.; Ray, I.; Kshetri, R.; Bhattacharya, S.; Saha-Sarkar, M.; Goswami, A.; Muralithar, S.; Singh, R.P.; Kumar, R.; Bhowmik, R.K.

2006-01-01

Excited states of 83 Rb, populated in the 76 Ge( 11 B,-bar 4nγ) reaction at a beam energy of 50 MeV, have been studied. The unfavoured signature partner (α=-1/2) of the πg 9/2 yrast band is proposed up to an excitation energy of 6669.4 keV and spin (31/2 + ). Lifetimes have been estimated for three states belonging to the favoured α=+1/2 band. The B(E2) values deduced from these lifetimes indicate a moderate quadrupole deformation of β 2 =0.20. Theoretical calculations within the framework of the particle-rotor-model suggest that low energy states before the onset of the νg 9/2 alignment at a rotational frequency of ∼0.5 MeV are prolate while those above this frequency have an oblate shape. The excited ΔI=1 band has been extended up to 5422.7 keV and spin 25/2 - . The B(M1) rates derived from the measured lifetimes decrease with spin. The results are in general agreement with an earlier TAC calculation, suggesting the interpretation of these states as arising from magnetic rotation

Structure of wobbling excitations in 163Lu

International Nuclear Information System (INIS)

Carlsson, B.G.

2007-01-01

Using a many-particles plus rotor model, wobbling excitations built on top of a triaxial superdeformed band in 163 Lu are investigated. By extracting all parameters for the rotor from a mean field calculation a good correspondence with calculations based on the random-phase approximation is achieved. (author)

Electronic structure of the misfit-layer compound (SnS)1.17NbS2 deduced from band-structure calculations and photoelectron spectra

NARCIS (Netherlands)

Fang, C.M.; Ettema, A.R.H.F.; Haas, C.; Wiegers, G.A.; Leuken, H. van; Groot, R.A. de

1995-01-01

In order to understand the electronic structure of the misfit-layer compound (SnS)1.17NbS2 we carried out an ab initio band-structure calculation of the closely related commensurate compound (SnS)1.20NbS2. The band structure is compared with calculations for NbS2 and for hypothetical SnS with

{Delta}I = 2 energy staggering in normal deformed dysprosium nuclei

Energy Technology Data Exchange (ETDEWEB)

Riley, M.A.; Brown, T.B.; Archer, D.E. [Florida State Univ., Tallahassee, FL (United States)] [and others

1996-12-31

Very high spin states (I{ge}50{Dirac_h}) have been observed in {sup 155,156,157}Dy. The long regular band sequences, free from sharp backbending effects, observed in these dysprosium nuclei offer the possibility of investigating the occurence of any {Delta}I = 2 staggering in normal deformed nuclei. Employing the same analysis techniques as used in superdeformed nuclei, certain bands do indeed demonstrate an apparent staggering and this is discussed.

Effect of pre-existing shear bands on the tensile mechanical properties of a bulk metallic glass

International Nuclear Information System (INIS)

Cao, Q.P.; Liu, J.W.; Yang, K.J.; Xu, F.; Yao, Z.Q.; Minkow, A.; Fecht, H.J.; Ivanisenko, J.; Chen, L.Y.; Wang, X.D.; Qu, S.X.; Jiang, J.Z.

2010-01-01

Bulk Zr 64.13 Cu 15.75 Ni 10.12 Al 10 metallic glass has been rolled at room temperature in two different directions, and the dependences of microstructure and tensile mechanical property on the degree of deformation and rolling directions have been investigated. No deformation-induced crystallization occurs except for shear bands. Shear band formation in conjugated directions is achieved in the specimen rolled in two directions, while rolling in one direction induces shear band formation only in a single direction. Pre-existing properly spaced soft inhomogeneities can stabilize shear bands and lead to tensile plastic strain, and the efficient intersection of shear bands in conjugated directions results in work-hardening behavior, which is further confirmed by in situ tensile scanning electron microscopic observation. Based on the experimental results obtained in two different specimen geometries and finite element analysis, it is deduced that a normal-stress-modified maximum shear stress criterion rather than a shear plane criterion can describe the conditions for the formation of shear bands in uniaxial tension.

Approximate eigensolutions of Dirac equation for the superposition ...

Indian Academy of Sciences (India)

2014-07-02

Jul 2, 2014 ... tion [5], superdeformation [6], identical bands [7] and magnetic moment [8]. ... angular momentum ˜l is nothing but the orbital angular momentum of the lower compo- ... However, the dependence of the quality of PSS on the relativistic effect has not been ... symmetries in the framework of the NU method.

Ground-State Band and Deformation of the Z = 102 Isotope N 254

International Nuclear Information System (INIS)

Reiter, P.; Khoo, T.L.; Lister, C.J.; Seweryniak, D.; Ahmad, I.; Alcorta, M.; Carpenter, M.P.; Cizewski, J.A.; Davids, C.N.; Gervais, G.; Greene, J.P.; Henning, W.F.; Janssens, R.V.; Lauritsen, T.; Siem, S.; Sonzogni, A.A.; Sullivan, D.; Uusitalo, J.; Wiedenhoever, I.; Amzal, N.; Butler, P.A.; Chewter, A.J.; Greenlees, P.T.; Herzberg, R.; Jones, G.D.; Cizewski, J.A.; Ding, K.Y.; Fotiades, N.; Fox, J.D.; Korten, W.; Leino, M.; Vetter, K.; Siem, S.

1999-01-01

The ground-state band of the Z=102 isotope 254 No has been identified up to spin 14, indicating that the nucleus is deformed. The deduced quadrupole deformation, β=0.27 , is in agreement with theoretical predictions. These observations confirm that the shell-correction energy responsible for the stability of transfermium nuclei is partly derived from deformation. The survival of 254 No up to spin 14 means that its fission barrier persists at least up to that spin. copyright 1999 The American Physical Society

Microscopic description of nuclear shapes

Energy Technology Data Exchange (ETDEWEB)

Egido, J.L.; Robledo, L.M.; Valor, A.; Villafranca, A. [Universidad Autonoma de Madrid (Spain)

1996-12-31

The approximate particle number theory for density dependent forces is sketched, the theory is applied to discuss properties of the superdeformed ground state and excited bands of {sup 192}Hg. The force used in the calculations is the finite range density dependent Gogny force. The agreement with the available experimental results is very satisfactory.

Transition Probabilities in the 1/2+(631) Band in {sup 235}U

Energy Technology Data Exchange (ETDEWEB)

Hoejeberg, M; Malmskog, S G

1969-09-15

Measurements of absolute transition probabilities in the rotational band built on the 1/2{sup +}(631) single particle state in {sup 235}U have been performed using delayed coincidence technique. The following half-lives were obtained: T{sub 1/2} (13.0 keV level) = (0.50 {+-} 0.03) nsec. T{sub 1/2} (51.7 k e V level) = (0.20 {+-} 0.02) nsec. From the deduced B(E2) and B(M1) values magnetic and electric parameters were determined which could be compared with predictions from the Nilsson model.

Evidence for {open_quotes}magnetic rotation{close_quotes} in nuclei: New results on the M1-bands of {sup 198,199}Pb

Energy Technology Data Exchange (ETDEWEB)

Clark, R.M. [Lawrence Berkeley National Lab., CA (United States)

1996-12-31

Lifetimes of states in four of the M1-bands in {sup 198,199}Pb have been determined through a Doppler Shift Attenuation Method measurement performed using the Gammasphere array. The deduced B(M1) values, which are a sensitive probe of the underlying mechanism for generating these sequences, show remarkable agreement with Tilted Axis Cranking (TAC) calculations. Evidence is also presented for the possible termination of the bands. The results represent clear evidence for a new concept in nuclear excitations: {open_quote}magnetic rotation{close_quote}.

Band offsets in HfTiO/InGaZnO4 heterojunction determined by X-ray photoelectron spectroscopy

International Nuclear Information System (INIS)

He, G.; Chen, X.F.; Lv, J.G.; Fang, Z.B.; Liu, Y.M.; Zhu, K.R.; Sun, Z.Q.; Liu, M.

2015-01-01

Highlights: • Band offsets in HfTiO/InGaZnO 4 heterojunction were determined by XPS. • Valence band offset of HfTiO/IGZO heterojunction is determined to be 0.35 eV. • Conduction band offset of 1.61 eV is deduced for HfTiO/IGZO heterojunction. - Abstract: In current report, X-ray photoelectron spectroscopy has been pursued to obtain the valence band discontinuity (ΔE v ) of sputter deposited HfTiO/InZnGaO 4 (IGZO) heterostructures. A ΔE v value of 0.32 ± 0.1 eV was obtained by using the Ga 2p3/2, Zn 2p3/2, and In 3d5/2 energy levels as references. Taking into consideration the experimental band gaps of 5.35 eV and 3.39 eV for HfTiO and IGZO thin films measured by absorption method, respectively, this would result in a conduction band offset of 1.64 eV in this heterostructure

Optical constants and band edge of amorphous zinc oxide thin films

International Nuclear Information System (INIS)

Khoshman, Jebreel M.; Kordesch, Martin E.

2007-01-01

The optical characteristics of amorphous zinc oxide (a-ZnO) thin films grown by radio frequency reactive magnetron sputtering on various substrates at temperature -8 -0.32, respectively. The band edge of the films on Si (100) and quartz has been determined by spectroscopic ellipsometry (3.39 ± 0.05 eV) and spectrophotometric (3.35 ± 0.05 eV) methods, respectively. From the angle dependence of the p-polarized reflectivity we deduce a Brewster angle of 60.5 deg. Measurement of the polarized optical properties shows a high transmissivity (81%-99%) and low absorptivity (< 5%) in the visible and near infrared regions at different angles of incidence. Also, we found that there was a higher absorptivity for wavelength < 370 nm. This wavelength, ∼ 370 nm, therefore indicated that the band edge for a-ZnO thin films is about 3.35 eV

Band structure in {sup 83}Rb from lifetime measurements

Energy Technology Data Exchange (ETDEWEB)

Ganguly, S. [Saha Institute of Nuclear Physics, Kolkata 700064 (India); Banerjee, P. [Saha Institute of Nuclear Physics, Kolkata 700064 (India)]. E-mail: polash.banerjee@saha.ac.in; Ray, I. [Saha Institute of Nuclear Physics, Kolkata 700064 (India); Kshetri, R. [Saha Institute of Nuclear Physics, Kolkata 700064 (India); Bhattacharya, S. [Saha Institute of Nuclear Physics, Kolkata 700064 (India); Saha-Sarkar, M. [Saha Institute of Nuclear Physics, Kolkata 700064 (India); Goswami, A. [Saha Institute of Nuclear Physics, Kolkata 700064 (India); Muralithar, S. [Nuclear Science Centre, Post Box 10502, New Delhi 110067 (India); Singh, R.P. [Nuclear Science Centre, Post Box 10502, New Delhi 110067 (India); Kumar, R. [Nuclear Science Centre, Post Box 10502, New Delhi 110067 (India); Bhowmik, R.K. [Nuclear Science Centre, Post Box 10502, New Delhi 110067 (India)

2006-03-20

Excited states of {sup 83}Rb, populated in the {sup 76}Ge({sup 11}B,-bar 4n{gamma}) reaction at a beam energy of 50 MeV, have been studied. The unfavoured signature partner ({alpha}=-1/2) of the {pi}g{sub 9/2} yrast band is proposed up to an excitation energy of 6669.4 keV and spin (31/2{sup +}). Lifetimes have been estimated for three states belonging to the favoured {alpha}=+1/2 band. The B(E2) values deduced from these lifetimes indicate a moderate quadrupole deformation of {beta}{sub 2}=0.20. Theoretical calculations within the framework of the particle-rotor-model suggest that low energy states before the onset of the {nu}g{sub 9/2} alignment at a rotational frequency of {approx}0.5 MeV are prolate while those above this frequency have an oblate shape. The excited {delta}I=1 band has been extended up to 5422.7 keV and spin 25/2{sup -}. The B(M1) rates derived from the measured lifetimes decrease with spin. The results are in general agreement with an earlier TAC calculation, suggesting the interpretation of these states as arising from magnetic rotation.

Comparisons of Satellite-Deduced Overlapping Cloud Properties and CALIPSO CloudSat Data

Science.gov (United States)

Chang, Fu-Lung; Minnis, Patrick; Lin, Bing; Sun-Mack, Sunny

2010-01-01

Introduction to the overlapped cloud properties derived from polar-orbiting (MODIS) and geostationary (GOES-12, -13, Meteosat-8, -9, etc.) meteorological satellites, which are produced at the NASA Langley Research Center (LaRC) cloud research & development team (NASA lead scientist: Dr. Patrick Minnis). Comparison of the LaRC CERES MODIS Edition-3 overlapped cloud properties to the CALIPSO and the CloudSat active sensing data. High clouds and overlapped clouds occur frequently as deduced by CALIPSO (44 & 25%), CloudSat (25 & 4%), and MODIS (37 & 6%). Large fractions of optically-thin cirrus and overlapped clouds are deduced from CALIPSO, but much smaller fractions are from CloudSat and MODIS. For overlapped clouds, the averaged upper-layer CTHs are about 12.8 (CALIPSO), 10.9 (CloudSat) and 10 km (MODIS), and the averaged lower-layer CTHs are about 3.6 (CALIPSO), 3.2 (CloudSat) and 3.9 km (MODIS). Based on comparisons of upper and lower-layer cloud properties as deduced from the MODIS, CALIPSO and CloudSat data, more enhanced passive satellite methods for retrieving thin cirrus and overlapped cloud properties are needed and are under development.

Energy of the 4(+) isomer and new bands in the odd-odd nucleus 74Br

International Nuclear Information System (INIS)

Doering, J.; Holcomb, J.W.; Johnson, T.D.; Riley, M.A.; Tabor, S.L.; Womble, P.C.; Winter, G.

1993-01-01

High-spin states of the odd-odd nucleus 74 Br were investigated via the reactions 58 Ni ( 19 F,2pn) 74 Br and 65 Cu( 12 C,3n) 74 Br at beam energies of 62 and 50 MeV, respectively. On the basis of coincidence data new levels have been introduced and partly grouped into rotational bands. Some of these new states decay to known levels of negative-parity bands built on both the ground state and the long-lived 4 (+) isomer. Thus, an excitation energy of 13.8 keV has been deduced for the long-lived isomer in 74 Br. The level sequences observed are interpreted in terms of Nilsson configurations in conjunction with collective excitations

Band offsets in HfTiO/InGaZnO{sub 4} heterojunction determined by X-ray photoelectron spectroscopy

Energy Technology Data Exchange (ETDEWEB)

He, G., E-mail: ganghe01@issp.ac.cn [School of Physics and Materials Science, Radiation Detection Materials & Devices Lab, Anhui University, Hefei 230601 (China); Chen, X.F. [School of Physics and Materials Science, Radiation Detection Materials & Devices Lab, Anhui University, Hefei 230601 (China); Lv, J.G., E-mail: jglv@hftc.edu.cn [School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601 (China); Fang, Z.B., E-mail: csfzb@usx.edu.cn [Department of Physics, Shaoxing University, Shaoxing 312000 (China); Liu, Y.M.; Zhu, K.R.; Sun, Z.Q. [School of Physics and Materials Science, Radiation Detection Materials & Devices Lab, Anhui University, Hefei 230601 (China); Liu, M., E-mail: mliu@issp.ac.cn [Key Laboratory of Materials Physics, Anhui Key Laboratory of Nanomaterials and Nanostructure, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)

2015-09-05

Highlights: • Band offsets in HfTiO/InGaZnO{sub 4} heterojunction were determined by XPS. • Valence band offset of HfTiO/IGZO heterojunction is determined to be 0.35 eV. • Conduction band offset of 1.61 eV is deduced for HfTiO/IGZO heterojunction. - Abstract: In current report, X-ray photoelectron spectroscopy has been pursued to obtain the valence band discontinuity (ΔE{sub v}) of sputter deposited HfTiO/InZnGaO{sub 4} (IGZO) heterostructures. A ΔE{sub v} value of 0.32 ± 0.1 eV was obtained by using the Ga 2p3/2, Zn 2p3/2, and In 3d5/2 energy levels as references. Taking into consideration the experimental band gaps of 5.35 eV and 3.39 eV for HfTiO and IGZO thin films measured by absorption method, respectively, this would result in a conduction band offset of 1.64 eV in this heterostructure.

Quasiparticle band structure for the Hubbard systems: Application to α-CeAl2

International Nuclear Information System (INIS)

Costa-Quintana, J.; Lopez-Aguilar, F.; Balle, S.; Salvador, R.

1990-01-01

A self-energy formalism for determining the quasiparticle band structure of the Hubbard systems is deduced. The self-energy is obtained from the dynamically screened Coulomb interaction whose bare value is the correlation energy U. A method for integrating the Schroedingerlike equation with the self-energy operator is given. The method is applied to the cubic Laves phase of α-CeAl 2 because it is a clear Hubbard system with a very complex electronic structure and, moreover, this system provides us with sufficient experimental data for testing our method

L-band passively harmonic mode-locked fiber laser based on a graphene saturable absorber

International Nuclear Information System (INIS)

Du, J; Zhang, S M; Li, H F; Meng, Y C; Li, X L; Hao, Y P

2012-01-01

We have proposed and demonstrated an L-band passively harmonic mode-locked fiber laser based on a graphene saturable absorber (SA). By adjusting the pump power and the polarization controller, we have experimentally observed L-band fundamental and harmonic mode-locked optical pulses. The fundamental optical pulse has the duration of 1.3 ps, and the maximum average output power of 13.16 mW at the incident pump power of 98.8 mW. The order of the harmonic mode-locked optical pulses can be changed over the range from the second to the fourth. From the experimental results, we deduced that the likely origin of the harmonic mode-locked self-stabilization was the result of global and local soliton interactions induced by the unstability continuous wave (CW) components

High resolution measurements of solar induced chlorophyll fluorescence in the Fraunhofer oxigen bands

Science.gov (United States)

Mazzoni, M.; Agati, G.; Cecchi, G.; Toci, G.; Mazzinghi, P.

2017-11-01

Spectra of solar radiance reflected by leaves close to the Fraunhofer bands show the net contribution of chlorophyll fluorescence emission which adds to the reflected solar spectra. In a laboratory experiment, a low stray light, high resolution, 0.85 m double monochromator was used to filter radiation living leaves still attached to the plant in correspondence of the 687 nm and 760 nm O2 absorption bands. Reference spectra from a non fluorescent white reference were also acquired. Acquisition was performed by a Microchannel plate (MCP) intensified diode array with 512 elements. A fit of the spectral data outside the absorption lines allowed to retrieve the spectral base-line as a function of wavelength for the reference panel and the leaf. Reflectance functions were determined extending the Plascyck equation system to all the resolved lines of the oxygen absorption bands and using the base-lines for the continuum values. Fluorescence was deduced from the same equation system, using both the measured leaf and reference radiance spectra and the leaf reflectance fitting function.

Different collectivity in the two signatures of the i13/2 stemming band in 167Yb

International Nuclear Information System (INIS)

Petkov, P; Gladnishki, K A; Dewald, A; Fransen, C; Hackstein, M; Jolie, J; Pissulla, Th; Rother, W; Zell, K O; Möller, O; Reese, M; Deloncle, I

2014-01-01

Six lifetimes have been determined in the 5/2 + [642] band from vi 13/2 parentage in 167 Yb by means of Recoil distance Doppler-shift (RDDS) measurements carried out at the Cologne FN tandem. The deduced transition strengths and the level scheme are reasonably described by Particle plus triaxial rotor model (PTRM) calculations except for the behavior of the quadrupole collectivity in the two signatures of the 5/2 + [642] band. In that band, the quadrupole collectivity of the favored signature is appreciably larger than this of the unfavored signature. The effect increases with increasing the spin. Naturally, the rigid PTRM cannot explain these features, but the structure of its wave functions suggests a possible solution. It is associated with the enhanced contribution of low-Ω orbitals from vi 13/2 parentage in the favored signature compared to the unfavored one. This could selectively increase the deformation of the favored signature band members and give rise to a dynamic shape coexistence taking place between the two signatures which needs quantitative explanation by future theoretical work.

Evidence for dipolar bands in mercury isotopes using EUROGAM multi-detector

International Nuclear Information System (INIS)

Le Coz, Y.

1995-01-01

This thesis is devoted to the study of nuclear structure around mass A 190 and in particular, to the search of oblate rotational dipole bands in mercury isotopes. The reactions used to populate high spin states in 192 Hg and 193 Hg were 160 Gd ( 36 S,n) 192 Hg and 150 Nd( 48 Ca, 5n) 193 Hg at beam energies of 159 and 213 MeV. Gamma-rays have been detected using the EUROGAM phase I array. Level schemes of those two nuclei have been extended up to an excitation energy of about 10 MeV and approximately spin 35h. In 192 Hg, two new dipole bands have been observed. Those two structures, as well as two similar structures in 193 Hg, have been connected to the low-lying states; so, excitation energy and bandhead spin of those bands have been deduced. Angular distribution and correlation analysis (specific to EUROGRAM phase I) have confirmed that the transitions are dipoles. After a general presentation of dipole bands in this A = 190 mass region, experimental results are compared with mean-field Hartree-Fock + BCS calculations, using the rotor plus quasi-particles model. The results are consistent with weakly oblate structures based on configurations which involve high-K proton orbitals driving the nucleus to an oblate shape. (author). 81 refs., 47 figs., 8 tabs., 4 ann

Collective dipole rotational bands in the A {approx} 200 region

Energy Technology Data Exchange (ETDEWEB)

Clark, R M; Wadsworth, R; Regan, P H [York Univ. (United Kingdom). Dept. of Physics; Paul, E S; Beausang, C W; Ali, I; Cullen, D M; Dagnall, P J; Fallon, P; Joyce, M J; Sharpey-Schafer, J F [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Astier, A; Meyer, M; Redon, N [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; Nazakewicz, W; Wyss, R [Joint Inst. for Heavy Ion Research, Oak Ridge, TN (United States)

1992-08-01

Rotational oblate bands consisting of regular sequences of magnetic dipole transitions have recently been identified in {sup 196-200}Pb. Their observation indicates a drastic change in the high-spin configurations between the Hg, Tl and {sup 194}Pb nuclei, in which SD bands are clearly observed, and the heavier Pb isotopes, where these weakly deformed oblate structures see to dominate. Angular correlation ratios show the transitions to be dipoles. Their magnetic nature can be deduced from intensity measurements, and they are characterized by small dynamic moments of inertia. Several of the bands have been interpreted as being built on high-K two-proton configurations coupled to an aligned pair of i{sub 13/2} neutrons in the even A nuclei, and to either one or three i{sub 13/2} neutrons in the odd A nuclei. Cranked shell model calculations predict the alignment of a pair of i{sub 13/2} neutrons (the AB crossing) at {omega} {approx} 0.18 MeV{Dirac_h}{sub -1}. The higher frequency crossing at {omega} {approx} 0.4 MeV{Dirac_h}{sub -1} may be due to the alignment of f{sub 5/2} neutrons, h{sub 11/2} protons, or both. 17 refs., 4 figs.

Method of estimating horizontal vectors of ionospheric electric field deduced from HF Doppler data

International Nuclear Information System (INIS)

Tsutsui, M.; Ogawa, T.; Kamide, Y.; Kroehl, H.W.; Hausman, B.A.

1988-01-01

An HF Doppler method for estimating the time variations of the horizontal electric field in the ionosphere is presented which takes into account, for long-lasting variations in the electric field, the effect of electron decay due to attachment and/or recombination processes. The method is applied to an isolated substorm event, using equivalent ionospheric current systems deduced from worldwide magnetometer data in the estimations. The present results are found to agree with data deduced from current systems and high latitude electrojet activity. 18 references

Structures of exotic nuclei

International Nuclear Information System (INIS)

Hamilton, J.H.

1987-01-01

Discoveries of many different types of nuclear shape coexistence are being found at both low and high excitation energies throughout the periodic table, as documented in recent reviews. Many new types of shape coexistence have been observed at low excitation energies, for examples bands on more than four different overlapping and coexisting shapes are observed in 185 Au, and competing triaxial and prolate shapes in 71 Se and 176 Pt. Discrete states in super-deformed bands with deformations β 2 ∼ 0.4-0.6, coexisting with other shapes, have been seen to high spin up to 60ℎ in 152 Dy, 132 Ce and 135 Nd. Super-deformed nuclei with N and Z both around 38 and around Z = 38, N ≥ 60. These data led to the discovery of new shell gaps and magic numbers of 38 for N and Z and 60 for N but now for deformed shapes. Marked differences in structure are observed at spins of 6 to 20 in nuclei in this region, which differ by only two protons; for example, 68 Ge and 70 Se. The differences are thought to be related to the competing shell gaps in these nuclei

Nuclear cluster states

International Nuclear Information System (INIS)

Rae, W.D.M.; Merchant, A.C.

1993-01-01

We review clustering in light nuclei including molecular resonances in heavy ion reactions. In particular we study the systematics, paying special attention to the relationships between cluster states and superdeformed configurations. We emphasise the selection rules which govern the formation and decay of cluster states. We review some recent experimental results from Daresbury and elsewhere. In particular we report on the evidence for a 7-α chain state in 28 Si in experiments recently performed at the NSF, Daresbury. Finally we begin to address theoretically the important question of the lifetimes of cluster states as deduced from the experimental energy widths of the resonances. (Author)

Angular momentum effects in subbarrier fusion

International Nuclear Information System (INIS)

Halbert, M.L.; Beene, J.R.; Hensley, D.C.; Honkanen, K.; Semkow, T.M.; Abenante, V.; Sarantites, D.G.; Li, Z.

1987-01-01

The authors discuss angular-momentum distributions σ l for the compound nucleus 164 Yb deduced from measurements of γ-ray multiplicity for all significant evaporation residues from fusion of 64 Ni and 100 Mo and 16 O + 148 Sm. At the lowest bombarding energies the σ l extend to higher l values than do predictions that include coupling of the principal inelastic channels, even if the coupling strengths are increased to match the experimental excitation function. Likewise, σ l from an energy-dependent real potential fitted to the excitation function fails to reproduce the experimental σ l distribution. No effects attributed to superdeformation were observed

Deducing Energy Consumer Behavior from Smart Meter Data

DEFF Research Database (Denmark)

Ebeid, Emad Samuel Malki; Heick, Rune; Jacobsen, Rune Hylsberg

2017-01-01

The ongoing upgrade of electricity meters to smart ones has opened a new market of intelligent services to analyze the recorded meter data. This paper introduces an open architecture and a unified framework for deducing user behavior from its smart main electricity meter data and presenting...... the results in a natural language. The framework allows a fast exploration and integration of a variety of machine learning algorithms combined with data recovery mechanisms for improving the recognition’s accuracy. Consequently, the framework generates natural language reports of the user’s behavior from...

Predicting superdeformed rotational band-head spin in A ∼ 190 ...

Indian Academy of Sciences (India)

Table1 Shi2 ab3. Becker4 CBM5 SAM6 Zeng7. 191Au(b1). 187. 184.6. 1.5. 0.1185. 9.5. 9.5. 7.5. 7.5. –. 7.5. 7.5. 7.5. 191Au(b2). 398. 398.7. 8.4. 0.0928. 17.5. 17.5 17.5. 17.5. –. 17.5. 17.5 17.5. 191Au(b3). 383. 383.3. 7.4. 0.0916. 16.5. 16.5 17.5. 17.5. –. 16.5. 16.5 16.5. 190Hg(b1). 317. 316.8. 6.8. 0.0834. 12. 12. 13. 13. 12.

Nuclear structure of light thallium isotopes as deduced from laser spectroscopy on a fast atom beam

International Nuclear Information System (INIS)

Bounds, J.A.

1985-08-01

After optimizing the system by experiments on /sup 201,203,205/Tl, the neutron-deficient isotopes 189-193 Tl have been studied using the collinear fast atom beam laser spectroscopy system at UNISOR on-line to the Holifield Heavy Ion Research Facility. A sensitive system for the measurements was developed since the light isotopes were available in mass-separated beams of only 7 x 10 4 to 4 x 10 5 atoms per second. By laser excitation of the 535 nm atomic transitions of atoms in the beam, the 6s 2 7s 2 S/sub 1/2/ and 6s 2 6s 2 P/sub 3/2/ hyperfine structures were measured, as were the isotope shifts of the 535 nm transitions. From these, the magnetic dipole moments, spectroscopic quadrupole moments and isotopic changes in mean-square charge radius were deduced. The magnetic dipole moments are consistent with previous data. The /sup 190,192/Tl isotopes show a considerable difference in quadrupole deformations as well as an anomalous isotope shift with respect to 194 Tl. A large isomer shift in 193 Tl is observed implying a larger deformation in the 9/2 - isomer than in the 1/2 + ground state. The /sup 189,191,193/Tl isomers show increasing deformation away from stability. A deformed shell model calculation indicates that this increase in deformation can account for the dropping of the 9/2 - band in these isotopes while an increase in neutron pairing correlations, having opposite and compensating effects on the rotational moment of inertia, maintains the 9/2 - strong-coupled band structure. 105 refs., 27 figs

Superdeformation, Hyperdeformation and Clustering in the Actinide Region

Science.gov (United States)

Krasznahorkay, A.; Habs, D.; Hunyadi, M.; Gassmann, D.; Csatlos, M.; Eisermann, Y.; Faestermann, T.; Graw, G.; Gulyas, J.; Hertenberger, R.; Maier, H. J.; Mate, Z.; Metz, A.; Ott, J.; Thirolf, P.; van der Werf, S. Y.

2001-03-01

Excited states in the second minimum of 240Pu were populated by the 238U(α ,2n) reaction at Eα=25 MeV. Conversion electrons from electromagnetic transitions preceding the fission of the 3.7 ns 240fPu shape isomer have been measured. In a combined analysis of e- and high resolution γ -ray spectroscopy data previously established octupole bands could be studied in more detail. In order to study higher lying states in the second and third minimum the 239Pu(d,pf)240Pu, and the 233U(d,pf)234U reactions have been studied with high energy resolution. The observed fission resonances were described as members of rotational bands with rotational parameters characteristic to super- and hyperdeformed nuclear shapes. The level density of the most strongly excited states has been compared to the prediction of the back-shifted Fermi-gas formula and the energy of the ground state in third minimum has been estimated for the first time in 234U. The fission fragment mass distribution of the hyperdeformed states in 236U has also been measured. The width of the mass distribution, coincident with the hyperdeformed bands, is significantly smaller than the ones obtained in coincidence with background regions below and above the resonances, which suggests a pear-shaped di-nuclear configuration of 236U in the third well of the potential barrier.

Quadrupole deformed and octupole collective bands in 228Ra

International Nuclear Information System (INIS)

Gulda, K.; Aas, A.J.

1998-01-01

Spins and parities for collective states in 228 Ra have been determined from conversion electron measurements with a mini-orange β spectrometer. The fast-timing βγγ(t) method has been used to measure lifetimes of T 1/2 =550(20) ps and 181(3) ps for the 2 + 1 and 4 + 1 members of the K=0 + band, and T 1/2 ≤7 ps and ≤6 ps for the 1 - 1 and 3 - 1 members of the K=0 - band, respectively. The quadrupole moments, Q 0 , deduced from the B(E2; 2 + 1 →0 + 1 ) and B(E2; 4 + 1 →2 + 1 ) rates are in good agreement with the previously measured value and the systematics of the region. However, the B(E1) rates of ≥4 x 10 -4 e 2 fm 2 , which represent the first B(E1) measurements for this nucleus, are at least 25 times larger than the value previously suggested for 228 Ra. The new results are consistent with the B(E1) rates recently measured for the neighbouring 227 Ra and reveal octupole correlations in 228 Ra. (orig.)

Measuring the band structures of periodic beams using the wave superposition method

Science.gov (United States)

Junyi, L.; Ruffini, V.; Balint, D.

2016-11-01

Phononic crystals and elastic metamaterials are artificially engineered periodic structures that have several interesting properties, such as negative effective stiffness in certain frequency ranges. An interesting property of phononic crystals and elastic metamaterials is the presence of band gaps, which are bands of frequencies where elastic waves cannot propagate. The presence of band gaps gives this class of materials the potential to be used as vibration isolators. In many studies, the band structures were used to evaluate the band gaps. The presence of band gaps in a finite structure is commonly validated by measuring the frequency response as there are no direct methods of measuring the band structures. In this study, an experiment was conducted to determine the band structure of one dimension phononic crystals with two wave modes, such as a bi-material beam, using the frequency response at only 6 points to validate the wave superposition method (WSM) introduced in a previous study. A bi-material beam and an aluminium beam with varying geometry were studied. The experiment was performed by hanging the beams freely, exciting one end of the beams, and measuring the acceleration at consecutive unit cells. The measured transfer function of the beams agrees with the analytical solutions but minor discrepancies. The band structure was then determined using WSM and the band structure of one set of the waves was found to agree well with the analytical solutions. The measurements taken for the other set of waves, which are the evanescent waves in the bi-material beams, were inaccurate and noisy. The transfer functions at additional points of one of the beams were calculated from the measured band structure using WSM. The calculated transfer function agrees with the measured results except at the frequencies where the band structure was inaccurate. Lastly, a study of the potential sources of errors was also conducted using finite element modelling and the errors in

Lifetime measurements in the picosecond range: achievements and perspectives

International Nuclear Information System (INIS)

Kruecken, R.

2000-01-01

Recent developments in the measurement of lifetimes in the picosecond range using the recoil distance method (RDM) are reviewed. Results from recent RDM experiments on superdeformed bands in the mass-190 region, shears, bands in the neutron deficient lead isotopes, and ground state bands in the mass-130 region are presented. New experimental devices for lifetime experiments at Yale, such as the New Yale Plunger Device (N.Y.P.D.), the SPEctrometer for Doppler-shift Experiments at Yale (SPEEDY) and the plans for the gas-filled recoil separator SASSYER are presented. Perspectives for the use of the RDM technique in the study of exotic nuclei and its potential use with radioactive beams are discussed. (author)

Nuclear Data Sheets for A = 196

International Nuclear Information System (INIS)

Huang Xiaolong

2007-01-01

The 1998 version of nuclear data sheets for A = 196 has been revised and updated on the basis of the experimental results from various decay and reaction studies before January 2006. The experimental data for all known nuclei of A = 196 (Os,Ir,Pt,Au,Hg, Tl,Pb,Bi,Po,At,Rn) have been reevaluated. The experimental methods, references,Jπ arguments,and necessary comments are given in the text. Summary band structure drawings and level schemes from both radioactive decay and reaction studies are presented. Also of special interest are the new identification of superdeformed bands in 196 Pb and 196 Bi

Temporal variability of TEC deduced from groundbased measurements

International Nuclear Information System (INIS)

Mosert, M.; Ezquer, R.G.; Jadur, C.; Radicella, S.M.

2001-01-01

This paper presents a study of the behaviour of the integrated total electron content (ITEC) deduced from electron density profiles of two Argentine stations: Tucuman (26.9 S; 294.6 E) and San Juan (31.5 S; 290.4 E). The ITEC values have been obtained by the technique proposed by Reinisch and Huang (2000). The database includes electron density profiles derived from ionograms recorded at 4 typical hours of the day (00.00, 06.00, 12.00 and 18.00 LT) during different seasonal and solar activity conditions. An analysis of the day to day variability of ITEC has also been done. (author)

Deducing T, C, and P invariance for strong interactions in topological particle theory

International Nuclear Information System (INIS)

Jones, C.E.

1985-01-01

It is shown here how the separate discrete invariances [time reversal (T), charge conjugation (C), and parity (P)] in strong interactions can be deduced as consequences of other S-matrix requirements in topological particle theory

Nuclear hyperdeformation and the Jacobi shape transition

Science.gov (United States)

Schunck, N.; Dudek, J.; Herskind, B.

2007-05-01

The possibility that atomic nuclei possess stable, extremely elongated (hyperdeformed) shapes at very high angular momentum is investigated in the light of the most recent experimental results. The crucial role of the Jacobi shape transitions for the population of hyperdeformed states is discussed and emphasized. State-of-the-art mean-field calculations including the most recent parametrization of the liquid-drop energy together with thermal effects and minimization algorithms allowing the spanning of a large deformation space predict the existence of a region of hyperdeformed nuclei in the mass A˜120 130: Te, Cs, Xe, I, and Ba isotopes. In agreement with predictions presented in reviews by J. Dudek, K. Pomorski, N. Schunck, and N. Dubray [Eur. Phys. J. A 20, 15 (2003)] and J. Dudek, N. Schunck, and N. Dubray [Acta Phys Pol. B 36, 975 (2005)], our extended calculations predict that only very short hyperdeformed bands composed of a dozen discrete transitions at the most are to be expected in contrast to the results known for the superdeformed bands. We stress the importance of the experimental research in terms of multiple-γ correlation analysis that proved to be very efficient for the superdeformation studies and seems very helpful in the even more difficult search for the discrete transitions in hyperdeformed nuclei.

The microball and Gammasphere: Research highlights and future directions

Energy Technology Data Exchange (ETDEWEB)

Devlin, M.; Sarantites, D.G.; LaFosse, D.R.; Lerma, F. [Washington Univ., Saint Louis, MO (United States)

1996-12-31

The Microball, a compact, 4{pi} charged-particle detector array, has been used in conjunction with Gammasphere for numerous physics experiments, and more are planned in the near future. A summary of this research program is presented, and the device and its capabilities are described. An example of its use in the study of the population and entry state excitation energy distributions of normal and superdeformed bands in {sup 82}Sr is presented.

Modal effects on amplitude perturbations on subionospheric signals (trimpis) deduced from two-frequency measurements

International Nuclear Information System (INIS)

Dowden, R.L.; Adams, C.D.D.

1989-01-01

Interference between the first two modes of Earth-ionosphere waveguide propagation at the high end of the VLF band (> 18 kHz) increases with distance from the transmitter out to very large distances and can add amplitude perturbations to the phase perturbations (trimpis) produced by lightning-induced electron precipitation (LEP) on the great circle path. Since the two modes have slightly different phase velocities, an interference pattern or standing wave is formed which is shifted slightly along the propagation path by the LEP-induced change in differential phase velocity. The model effect at the receiver depends on the local gradient (along the great circle path) of amplitude with respect to the differential phase. Since this differential or mode beat phase varies with frequency, measurement of the resultant amplitude at two close frequencies enables an estimation of the modal effects. In this study, measurements were made at Dunedin at the two MSK frequencies, 22,250 Hz and 22,350 Hz, of the transmitter NWC, during a night of frequent one-dimensional trimpis (i.e., those produced by large-area LEP occurring close to the great circle path) and of strong and varying modal interference. Modal generation or modification of trimpi amplitude was related to the local gradient of amplitude as expected. From these results it was deduced that modal modification of echo trimpis (those produced by small area LEP occurring well off the great circle path), even under extreme conditions, is insignificant

Heavy-ion optical potential for sub-barrier fusion deduced from a dispersion relation

International Nuclear Information System (INIS)

Kim, B.T.; Kim, H.C.; Park, K.E.

1988-01-01

The heavy-ion energy-dependent optical potentials for the 16 O+ 208 Pb system are deduced from a dispersion relation. These potentials are used to analyze the elastic scattering, fusion, and spin distributions of compound nuclei for the system in a unified way based on the direct reaction theory. It turns out that the energy dependence of the optical potential is essential in explaining the data at near- and sub-barrier energies. The real part of the energy-dependent optical potential deduced was also used in calculating the elastic and fusion cross sections by the conventional barrier penetration model using an incoming wave boundary condition. The predictions of the elastic scattering, fusion cross sections, and the spin distributions of compound nuclei are not satisfactory compared with those from the direct reaction approach. It seems to originate from the fact that this model neglects absorption around the Coulomb barrier region

The carrier transport mechanism and band offset at the interface of ZnO/n-Si(111) heterojunction

Energy Technology Data Exchange (ETDEWEB)

Li, Yapeng, E-mail: liyp1984@126.com [School of Materials Science and Engineering, Shaanxi University of Technology, Hanzhong 723001 (China); Li, Yingfeng [School of Electrical Engineering, Shaanxi University of Technology, Hanzhong 723001 (China); Wang, Jianyuan [School of Nature and Applied Science, Northwestern Polytechnical University, Xi' an 710072 (China); He, Zhirong; Zhang, Yonghong; Yu, Qi; Hou, Juncai [School of Materials Science and Engineering, Shaanxi University of Technology, Hanzhong 723001 (China)

2017-05-15

Highlights: • The carrier transport deviated from ideal thermionic emission model. • One deep level present at the interface of ZnO/n-Si(111) heterojunction. • The band offsets of ZnO/n-Si(111) heterojunction are a type-II band alignment. - Abstract: The ZnO films were deposited on the surface of n-Si(111) substrate by pulsed laser deposition for fabrication of ZnO/n-Si(111) heterojunction. The carrier transport mechanism, deep level defects and band offsets at the interface of ZnO/n-Si(111) heterojunction were investigated by current- voltage measurement, deep level transient spectroscopy, X-ray photoelectron spectroscopy, respectively. The results showed that the barrier height and ideality factor values varied in the different linear voltage range by using the thermionic emission model, which was due to the deep level participated in carrier transport. Meanwhile, it was found that one deep level appeared at the interface of ZnO/n-Si(111) heterojunction with densities of the deep level about 8.5 × 10{sup 16} cm{sup −3} and activation energies about 224 m eV, which originated from O{sup 2−} vacancies of ZnO films. In addition, the valence band offset of the ZnO/n-Si(111) heterojunction can be calculated to be −2.4 ± 0.15 eV. The conduction band offset is deduced to be −3.5 ± 0.15 eV from the valence band offset value, indicating that the band offsets of ZnO/n-Si(111) heterojunction is a type-II band alignment.

Sub-band gap photo-enhanced secondary electron emission from high-purity single-crystal chemical-vapor-deposited diamond

International Nuclear Information System (INIS)

Yater, J. E.; Shaw, J. L.; Pate, B. B.; Feygelson, T. I.

2016-01-01

Secondary-electron-emission (SEE) current measured from high-purity, single-crystal (100) chemical-vapor-deposited diamond is found to increase when sub-band gap (3.06 eV) photons are incident on the hydrogenated surface. Although the light does not produce photoemission directly, the SEE current increases by more than a factor of 2 before saturating with increasing laser power. In energy distribution curves (EDCs), the emission peak shows a corresponding increase in intensity with increasing laser power. However, the emission-onset energy in the EDCs remains constant, indicating that the bands are pinned at the surface. On the other hand, changes are observed on the high-energy side of the distribution as the laser power increases, with a well-defined shoulder becoming more pronounced. From an analysis of this feature in the EDCs, it is deduced that upward band bending is present in the near-surface region during the SEE measurements and this band bending suppresses the SEE yield. However, sub-band gap photon illumination reduces the band bending and thereby increases the SEE current. Because the bands are pinned at the surface, we conclude that the changes in the band levels occur below the surface in the electron transport region. Sample heating produces similar effects as observed with sub-band gap photon illumination, namely, an increase in SEE current and a reduction in band bending. However, the upward band bending is not fully removed by either increasing laser power or temperature, and a minimum band bending of ∼0.8 eV is established in both cases. The sub-band gap photo-excitation mechanism is under further investigation, although it appears likely at present that defect or gap states play a role in the photo-enhanced SEE process. In the meantime, the study demonstrates the ability of visible light to modify the electronic properties of diamond and enhance the emission capabilities, which may have potential impact for diamond-based vacuum electron

CONSISTENT USE OF THE KALMAN FILTER IN CHEMICAL TRANSPORT MODELS (CTMS) FOR DEDUCING EMISSIONS

Science.gov (United States)

Past research has shown that emissions can be deduced using observed concentrations of a chemical, a Chemical Transport Model (CTM), and the Kalman filter in an inverse modeling application. An expression was derived for the relationship between the "observable" (i.e., the con...

Analysis of Fade Dynamic at Ku-Band in Malaysia

Directory of Open Access Journals (Sweden)

Siat Ling Jong

2014-01-01

Full Text Available This work investigates fade dynamics of satellite communication systems in equatorial heavy rain region based on a one year of Ku-band propagation measurement campaign carried out in Universiti Teknologi Malaysia (UTM, Johor, Malaysia. First order statistics of rain attenuation are deduced and the results are found to be in good agreement with those obtained from other beacon measurements gathered within the same area (Kuala Lumpur. Moreover, the fade duration and slope statistics of the satellite signal variations are also carefully derived and subsequently compared with the ITU-R recommendation model. Such information is useful for the system operator and radio communication engineer for the design of appropriate fade mitigation techniques as well as the quality of service that could be offered to the user (according to the time interval for a typical day. Further evaluation on the performances of several ITU-R models in the heavy rain region are needed based on the measurement database available of this climatic region.

The hierarchically organized splitting of chromosome bands into sub-bands analyzed by multicolor banding (MCB).

Science.gov (United States)

Lehrer, H; Weise, A; Michel, S; Starke, H; Mrasek, K; Heller, A; Kuechler, A; Claussen, U; Liehr, T

2004-01-01

To clarify the nature of chromosome sub-bands in more detail, the multicolor banding (MCB) probe-set for chromosome 5 was hybridized to normal metaphase spreads of GTG band levels at approximately 850, approximately 550, approximately 400 and approximately 300. It could be observed that as the chromosomes became shorter, more of the initial 39 MCB pseudo-colors disappeared, ending with 18 MCB pseudo-colored bands at the approximately 300-band level. The hierarchically organized splitting of bands into sub-bands was analyzed by comparing the disappearance or appearance of pseudo-color bands of the four different band levels. The regions to split first are telomere-near, centromere-near and in 5q23-->q31, followed by 5p15, 5p14, and all GTG dark bands in 5q apart from 5q12 and 5q32 and finalized by sub-band building in 5p15.2, 5q21.2-->q21.3, 5q23.1 and 5q34. The direction of band splitting towards the centromere or the telomere could be assigned to each band separately. Pseudo-colors assigned to GTG-light bands were resistant to band splitting. These observations are in concordance with the recently proposed concept of chromosome region-specific protein swelling. Copyright 2003 S. Karger AG, Basel

Workshop on nuclear structure at moderate and high spin: Slide report

International Nuclear Information System (INIS)

1986-10-01

The workshop was scheduled to coincide with the beginning of operation of a number of large arrays of Compton-suppressed germanium detectors. The workshop was divided into 14 sessions containing 3 presentations each. The topics of these sessions were superdeformation, heavy rare earths, single-particle configurations, band termination, continuum properties, light rare-earths, new techniques, high temperatures, transfer reactions, transition region, shapes, lifetimes, and moments. This publication consists of the slides used in all of the presentations at the workshop

Spin measurement for symmetric fission states of sup 24 Mg. A new angle on the sup 12 C+ sup 12 C interaction

Energy Technology Data Exchange (ETDEWEB)

Fulton, B.R.; Bennett, S.J.; Freer, M.; Murgatroyd, J.T. (School of Physics and Space Research, Birmingham Univ. (United Kingdom)); Gyapong, G.J.; Jarvis, N.S.; Jones, C.D.; Watson, D.L. (Dept. of Physics, York Univ. (United Kingdom)); Brown, J.D.; Rae, W.D.M.; Smith, A.E. (Dept. of Nuclear Physics, Oxford Univ. (United Kingdom)); Lilley, J.S. (Daresbury Lab., Warrington (United Kingdom))

1991-09-19

A new high resolution measurement of the {sup 12}C({sup 24}Mg, {sup 12}C{sup 12}C){sup 12}C breakup reaction has been performed. Sequential breakup is observed from specific states in {sup 24}Mg at excitation energies ranging from 20 to 26 MeV. Angular correlation measurements indicate that states with spins ranging from J=4 to 8 are populated. These states are consistent with superdeformed shape isomeric bands predicted by cranked cluster model and Nilsson-Strutinsky calculations. (orig.).

High-K precession modes: Axially symmetric limit of wobbling motion in the cranked random-phase approximation description

International Nuclear Information System (INIS)

Shimizu, Yoshifumi R.; Matsuzaki, Masayuki; Matsuyanagi, Kenichi

2005-01-01

The rotational band built on the high-K multi-quasiparticle state can be interpreted as a multi-phonon band of the precession mode, which represents the precessional rotation about the axis perpendicular to the direction of the intrinsic angular momentum. By using the axially symmetric limit of the random-phase approximation (RPA) formalism developed for the nuclear wobbling motion, we study the properties of the precession modes in 178 W: the excitation energies, B(E2) and B(M1) values. We show that the excitations of such a specific type of rotation can be well described by the RPA formalism, which gives new insight into the wobbling motion in the triaxial superdeformed nuclei from a microscopic viewpoint

The DEDUCE Guided Query tool: providing simplified access to clinical data for research and quality improvement.

Science.gov (United States)

Horvath, Monica M; Winfield, Stephanie; Evans, Steve; Slopek, Steve; Shang, Howard; Ferranti, Jeffrey

2011-04-01

In many healthcare organizations, comparative effectiveness research and quality improvement (QI) investigations are hampered by a lack of access to data created as a byproduct of patient care. Data collection often hinges upon either manual chart review or ad hoc requests to technical experts who support legacy clinical systems. In order to facilitate this needed capacity for data exploration at our institution (Duke University Health System), we have designed and deployed a robust Web application for cohort identification and data extraction--the Duke Enterprise Data Unified Content Explorer (DEDUCE). DEDUCE is envisioned as a simple, web-based environment that allows investigators access to administrative, financial, and clinical information generated during patient care. By using business intelligence tools to create a view into Duke Medicine's enterprise data warehouse, DEDUCE provides a Guided Query functionality using a wizard-like interface that lets users filter through millions of clinical records, explore aggregate reports, and, export extracts. Researchers and QI specialists can obtain detailed patient- and observation-level extracts without needing to understand structured query language or the underlying database model. Developers designing such tools must devote sufficient training and develop application safeguards to ensure that patient-centered clinical researchers understand when observation-level extracts should be used. This may mitigate the risk of data being misunderstood and consequently used in an improper fashion. Copyright © 2010 Elsevier Inc. All rights reserved.

Scaling Universality between Band Gap and Exciton Binding Energy of Two-Dimensional Semiconductors

Science.gov (United States)

Jiang, Zeyu; Liu, Zhirong; Li, Yuanchang; Duan, Wenhui

2017-06-01

Using first-principles G W Bethe-Salpeter equation calculations and the k .p theory, we unambiguously show that for two-dimensional (2D) semiconductors, there exists a robust linear scaling law between the quasiparticle band gap (Eg) and the exciton binding energy (Eb), namely, Eb≈Eg/4 , regardless of their lattice configuration, bonding characteristic, as well as the topological property. Such a parameter-free universality is never observed in their three-dimensional counterparts. By deriving a simple expression for the 2D polarizability merely with respect to Eg, and adopting the screened hydrogen model for Eb, the linear scaling law can be deduced analytically. This work provides an opportunity to better understand the fantastic consequence of the 2D nature for materials, and thus offers valuable guidance for their property modulation and performance control.

First Evidence for the Wobbling Mode in A Triaxial Superdeformed Odd-A Nucleus

International Nuclear Information System (INIS)

Hamamoto, I.; Odegaerd, S.W.; Hagemann, G.B.

2001-01-01

The wobbling mode is uniquely related to rotation of a triaxial body. The Lu-Hf isotopes with N ∼ 94 provides a possible region of nuclei with pronounced triaxiality. We have investigated 163 Lu through the fusion- evaporation reaction 139 La( 29 Si,5n) 163 Lu with a beam energy of 152 MeV. The electromagnetic properties of several connecting transitions between two presumably Triaxial, Super Deformed (TSD) bands have been studied. New particle-rotor calculations in which an aligned i 13/2 proton is coupled to a ''wobbling'' core are presented and evidence for the assignment of the excited TSD band as a wobbling mode built on the yrast TSD band in 163 Lu is given. (author)

SINGLE-BAND, TRIPLE-BAND, OR MULTIPLE-BAND HUBBARD MODELS

NARCIS (Netherlands)

ESKES, H; SAWATZKY, GA

1991-01-01

The relevance of different models, such as the one-band t-J model and the three-band Emery model, as a realistic description of the electronic structure of high-T(c) materials is discussed. Starting from a multiband approach using cluster calculations and an impurity approach, the following

The Structure of Nuclei Far from Stability

International Nuclear Information System (INIS)

Zganjar, E.F.

1999-01-01

From among a number of important nuclear structure results that have emerged from our research program during the past few years, two stand out as being of extra significance. These are: (a) the identification of a diabatic coexisting structure in 187 Au which arises solely from differences in proton occupation of adjacent oscillator shells, and (b) the realization of a method for estimating EO strength in nuclei and the resulting prediction that the de-excitation of superdeformed bands may proceed, in some cases, by strong EO transitions

Frequency band adjustment match filtering based on variable frequency GPR antennas pairing scheme for shallow subsurface investigations

Science.gov (United States)

Shaikh, Shahid Ali; Tian, Gang; Shi, Zhanjie; Zhao, Wenke; Junejo, S. A.

2018-02-01

Ground penetrating Radar (GPR) is an efficient tool for subsurface geophysical investigations, particularly at shallow depths. The non-destructiveness, cost efficiency, and data reliability are the important factors that make it an ideal tool for the shallow subsurface investigations. Present study encompasses; variations in central frequency of transmitting and receiving GPR antennas (Tx-Rx) have been analyzed and frequency band adjustment match filters are fabricated and tested accordingly. Normally, the frequency of both the antennas remains similar to each other whereas in this study we have experimentally changed the frequencies of Tx-Rx and deduce the response. Instead of normally adopted three pairs, a total of nine Tx-Rx pairs were made from 50 MHz, 100 MHz, and 200 MHz antennas. The experimental data was acquired at the designated near surface geophysics test site of the Zhejiang University, Hangzhou, China. After the impulse response analysis of acquired data through conventional as well as varied Tx-Rx pairs, different swap effects were observed. The frequency band and exploration depth are influenced by transmitting frequencies rather than the receiving frequencies. The impact of receiving frequencies was noticed on the resolution; the more noises were observed using the combination of high frequency transmitting with respect to low frequency receiving. On the basis of above said variable results we have fabricated two frequency band adjustment match filters, the constant frequency transmitting (CFT) and the variable frequency transmitting (VFT) frequency band adjustment match filters. By the principle, the lower and higher frequency components were matched and then incorporated with intermediate one. Therefore, this study reveals that a Tx-Rx combination of low frequency transmitting with high frequency receiving is a better choice. Moreover, both the filters provide better radargram than raw one, the result of VFT frequency band adjustment filter is

Opening the band gap of graphene through silicon doping for the improved performance of graphene/GaAs heterojunction solar cells.

Science.gov (United States)

Zhang, S J; Lin, S S; Li, X Q; Liu, X Y; Wu, H A; Xu, W L; Wang, P; Wu, Z Q; Zhong, H K; Xu, Z J

2016-01-07

Graphene has attracted increasing interest due to its remarkable properties. However, the zero band gap of monolayered graphene limits it's further electronic and optoelectronic applications. Herein, we have synthesized monolayered silicon-doped graphene (SiG) with large surface area using a chemical vapor deposition method. Raman and X-ray photoelectron spectroscopy measurements demonstrate that the silicon atoms are doped into graphene lattice at a doping level of 2.7-4.5 at%. Electrical measurements based on a field effect transistor indicate that the band gap of graphene has been opened via silicon doping without a clear degradation in carrier mobility, and the work function of SiG, deduced from ultraviolet photoelectron spectroscopy, was 0.13-0.25 eV larger than that of graphene. Moreover, when compared with the graphene/GaAs heterostructure, SiG/GaAs exhibits an enhanced performance. The performance of 3.4% silicon doped SiG/GaAs solar cell has been improved by 33.7% on average, which was attributed to the increased barrier height and improved interface quality. Our results suggest that silicon doping can effectively engineer the band gap of monolayered graphene and SiG has great potential in optoelectronic device applications.

Studies of normal deformation in {sup 151}Dy

Energy Technology Data Exchange (ETDEWEB)

Nisius, D.; Janssens, R.V.F.; Crowell, B. [and others

1995-08-01

The wealth of data collected in the study of superdeformation in {sup 151}Dy allowed for new information to be obtained on the normally deformed structures in this nucleus. At high spin several new yrast states have been identified for the first time. They were associated with single-particle excitations. Surprisingly, a sequence was identified with energy spacings characteristic of a rotational band of normal ({beta}2 {approximately} 0.2) deformation. The bandhead spin appears to be 15/2{sup -} and the levels extend up to a spin of 87/2{sup -}. A clear backbend is present at intermediate spins. While a similar band based on a bandhead of 6{sup +} is known in {sup 152}Dy, calculations suggest that this collective prolate band should not be seen in {sup 151}Dy. In the experiment described earlier in this report that is aimed at determining the deformations associated with the SD bands in this nucleus and {sup 152}Dy, the deformation associated with this band will be determined. This will provide further insight into the origin of this band.

Complete amino acid sequence of human intestinal aminopeptidase N as deduced from cloned cDNA

DEFF Research Database (Denmark)

Cowell, G M; Kønigshøfer, E; Danielsen, E M

1988-01-01

The complete primary structure (967 amino acids) of an intestinal human aminopeptidase N (EC 3.4.11.2) was deduced from the sequence of a cDNA clone. Aminopeptidase N is anchored to the microvillar membrane via an uncleaved signal for membrane insertion. A domain constituting amino acid 250...

L-band brightness temperature disaggregation for use with S-band and C-band radiometer data for WCOM

Science.gov (United States)

Yao, P.; Shi, J.; Zhao, T.; Cosh, M. H.; Bindlish, R.

2017-12-01

There are two passive microwave sensors onboard the Water Cycle Observation Mission (WCOM), which includes a synthetic aperture radiometer operating at L-S-C bands and a scanning microwave radiometer operating from C- to W-bands. It provides a unique opportunity to disaggregate L-band brightness temperature (soil moisture) with S-band C-bands radiometer data. In this study, passive-only downscaling methodologies are developed and evaluated. Based on the radiative transfer modeling, it was found that the TBs (brightness temperature) between the L-band and S-band exhibit a linear relationship, and there is an exponential relationship between L-band and C-band. We carried out the downscaling results by two methods: (1) downscaling with L-S-C band passive measurements with the same incidence angle from payload IMI; (2) downscaling with L-C band passive measurements with different incidence angle from payloads IMI and PMI. The downscaling method with L-S bands with the same incident angle was first evaluated using SMEX02 data. The RMSE are 2.69 K and 1.52 K for H and V polarization respectively. The downscaling method with L-C bands is developed with different incident angles using SMEX03 data. The RMSE are 2.97 K and 2.68 K for H and V polarization respectively. These results showed that high-resolution L-band brightness temperature and soil moisture products could be generated from the future WCOM passive-only observations.

IR thermographic observation and shear bands plasticity analysis in Fe-based metallic glass

International Nuclear Information System (INIS)

Bouzakher, B.; Benameur, T.; Sidhom, H.

2009-01-01

Infrared thermography observation and in situ atomic force microscopy characterization were carried out to investigate the mechanical damage processes at the edge-notch region of large ribbons of Fe 78 Si 10 B 12 metallic glass. An obvious thermoelastic and inelastic degradation phenomenon was observed ahead at the notched region of the specimens, which probably result from free volume accumulation process and shear band activity during plane stress solicitations. Moreover, AFM topographic and frictional analysis of changes in the crack path during stable crack propagation regime revealed a periodic morphology evolution, formation of nanoscale damage cavity in the range of 20-140 nm and a maximum temperature rise ahead of the pre-crack tip was found in the order of 1.5 deg. C. The nanometer scaled shear offset, discreteness and shear bands density were determined. While these key parameters play a role in observing a large plastic zone in front of the crack, however they are unable to explain the distinct intrinsic ductility of some monolithic metallic glasses. A general Mohr-Coulomb-type constitutive description was used to deduce analytic expressions for prediction of the variation of hydrostatic component of the applied stress to the shear stress ratio as function of Poisson's ratio.

Research on convergence of nuclear rotational spectra formula

International Nuclear Information System (INIS)

Chen Yongjing; Xu Fuxin

2001-01-01

The superdeformed bands in the A-190 region are systematically analyzed using four-parameter rotational spectra formula of Bohr-Mottelson's I(I + 1) expansion. The convergence of two-parameter ab formula is compared with that of three-parameter abc formula by four parameters A, B, C, D. The result shows that the four-parameter value relation does not support the theoretically expected values of ab and abc formulas, but comparatively the four-parameter value relation agrees with the theoretically expected value of ab formula better than that of abc formula

Wobbling phonon excitations, coexisting with normal deformed structures in 163Lu

International Nuclear Information System (INIS)

Jensen, D.R.; Hagemann, G.B.; Hamamoto, I.; Oedegard, S.W.; Bergstroem, M.; Herskind, B.; Sletten, G.; Toermaenen, S.; Wilson, J.N.; Tjoem, P.O.; Spohr, K.; Huebel, H.; Goergen, A.; Schoenwasser, G.; Bracco, A.; Leoni, S.; Maj, A.; Petrache, C.M.; Bednarczyk, P.; Curien, D.

2002-01-01

Wobbling is a rotational mode unique to a triaxial body. The Lu-Hf isotopes with N∼94 at high spin provide a possible region of nuclei with pronounced triaxiality. We have investigated 163 Lu through the fusion-evaporation reaction 139 La( 29 Si,5n) 163 Lu with a beam energy of 152 MeV. Three excited bands decaying into the known, presumably triaxial, superdeformed (TSD) band built on the i 13/2 proton orbital are observed. The electromagnetic properties of the connecting transitions from the two strongest populated excited TSD bands have been investigated. New particle-rotor calculations in which one i 13/2 quasiproton is coupled to the core of triaxial shape produce a variety of bands, whose properties can clearly be interpreted either as 'wobbling' or 'cranking' motion of the core. Evidence for the assignment of the excited TSD bands as one, and possibly even two wobbling phonon modes built on the yrast TSD band in 163 Lu is given. These triaxial bands coexist with bands built on quasiparticle excitations in the normal deformed (ND) minimum for which new data are also presented

A Novel Ku-Band/Ka-Band and Ka-Band/E-Band Multimode Waveguide Couplers for Power Measurement of Traveling-Wave Tube Amplifier Harmonic Frequencies

Science.gov (United States)

Wintucky, Edwin G.; Simons, Rainee N.

2015-01-01

This paper presents the design, fabrication and test results for a novel waveguide multimode directional coupler (MDC). The coupler, fabricated from two dissimilar frequency band waveguides, is capable of isolating power at the second harmonic frequency from the fundamental power at the output port of a traveling-wave tube (TWT) amplifier. Test results from proof-of-concept demonstrations are presented for a Ku-band/Ka-band MDC and a Ka-band/E-band MDC. In addition to power measurements at harmonic frequencies, a potential application of the MDC is in the design of a satellite borne beacon source for atmospheric propagation studies at millimeter-wave (mm-wave) frequencies (Ka-band and E-band).

Transition metal atoms absorbed on MoS2/h-BN heterostructure: stable geometries, band structures and magnetic properties.

Science.gov (United States)

Wu, Yanbing; Huang, Zongyu; Liu, Huating; He, Chaoyu; Xue, Lin; Qi, Xiang; Zhong, Jianxin

2018-06-15

We have studied the stable geometries, band structures and magnetic properties of transition-metal (V, Cr, Mn, Fe, Co and Ni) atoms absorbed on MoS2/h-BN heterostructure systems by first-principles calculations. By comparing the adsorption energies, we find that the adsorbed transition metal (TM) atoms prefer to stay on the top of Mo atoms. The results of the band structure without spin-orbit coupling (SOC) interaction indicate that the Cr-absorbed systems behave in a similar manner to metals, and the Co-absorbed system exhibits a half-metallic state. We also deduce that the V-, Mn-, Fe-absorbed systems are semiconductors with 100% spin polarization at the HOMO level. The Ni-absorbed system is a nonmagnetic semiconductor. In contrast, the Co-absorbed system exhibits metallic state, and the bandgap of V-absorbed system decreases slightly according to the SOC calculations. In addition, the magnetic moments of all the six TM atoms absorbed on the MoS2/h-BN heterostructure systems decrease when compared with those of their free-standing states.

IKP annual report 1988

International Nuclear Information System (INIS)

Kilian, K.; Maier, R.A.; Schult, O.; Seyfarth, H.; Speth, J.; Turek, P.

1989-04-01

The main tasks of the institute in 1988 were to propose an experimental programm for COSY and the upgrading of the cyclotron as COSY-injector. In collaboration with various divisions of the KFA infrastructure the institute participates in the realization of the COSY-project. The design and progress in the realization of COSY was examined by different advisory committees (KEB, SCC). The most important results in our current research programm in 1988 are: (i) Observation of high energy bremsstrahlung in connection with investigations of giant resonances in hot nuclei. (ii) A discrete superdeformed band was identified in 146 Gd by the OSIRIS-collaboration; also in 180 Os superdeformation was observed. (iii) The double-magic nucleus 96 Zr shows a strong octupol-collectivity in a certain transition to the groundstate. (iv) In the antiproton-proton reaction anti pp → anti ΛΛ at LEAR/CERN near threshold a strong p-wave dominance was observed and it was confirmed that the anti ΛΛ production occurs in a triplet state only. (v) The theoretical interpretation for the dominant anti ΛΛ p-wave is the existence for a resonance state in this region. (orig./HSI)

The band structures of three-dimensional nonlinear plasma photonic crystals

Directory of Open Access Journals (Sweden)

Hai-Feng Zhang

2018-01-01

Full Text Available In this paper, the properties of the photonic band gaps (PBGs for three-dimensional (3D nonlinear plasma photonic crystals (PPCs are theoretically investigated by the plane wave expansion method, whose equations for calculations also are deduced. The configuration of 3D nonlinear PPCs is the Kerr nonlinear dielectric spheres (Kerr effect is considered inserted in the plasma background with simple-cubic lattices. The inserted dielectric spheres are Kerr nonlinear dielectrics whose relative permittivities are the functions of the external light intensity. Three different Kerr nonlinear dielectrics are considered, which can be expressed as the functions of space coordinates. The influences of the parameters for the Kerr nonlinear dielectrics on the PBGs also are discussed. The calculated results demonstrate that the locations, bandwidths and number of PBGs can be manipulated with the different Kerr nonlinear dielectrics. Compared with the conventional 3D dielectric PCs and PPCs with simple-cubic lattices, the more PBGs or larger PBG can be achieved in the 3D nonlinear PPCs. Those results provide a new way to design the novel devices based on the PPCs.

Coriolis force and nuclear deformation: cadmium and lead isotopes results with the EUROBALL gamma multidetector

International Nuclear Information System (INIS)

Buforn, Nadege

2001-01-01

This work is devoted to the study of the nuclear matter at high rotational frequency. Thanks to the new generation of γ-ray multidetector array, as EUROGAM then EUROBALL, we propose to identify two sorts of nuclei belonging to two different mass region. Their identification is based on the detection of their γ-rays of des-excitation. We will follow the evolution of the influence of the Coriolis force at the microscopic scale. The cadmium nuclei 113-116 Cd have been populated using heavy-ion induced fission reaction ( 28 Si+ 176 Yb at 145 MeV). Decoupled bands have been identified in odd-nuclei, produced for the first time at high spin. As they were considered as the best example of vibrational nuclei during their studies by radioactivity, they exhibit a small prolate deformation, confirmed by our microscopic calculations performed for even-even nuclei. The odd superdeformed nucleus 197 Pb have been studied via a fusion-evaporation reaction ( 18 O+ 186 W at 117 MeV). We have established the cross-talk transitions between the two signature partners. The experimental measurement of the branching ratio B(M1)/B(E2) allows us to extract the magnetic properties of the superdeformed matter, conforming the lack of quenching for the neutrons. The Coriolis force depends on the nuclei deformation and on the individual configuration. In cadmium nuclei, the single neutron νh 11/2 , Ω=1/2 is decoupled from the motion of the core, whereas in superdeformed nuclei, the Coriolis effect is much weaker on the νj 15/2 , Ω = 5/2 neutron. (author)

Reward banding to determine reporting rate of recovered mourning dove bands

Science.gov (United States)

Tomlinson, R.E.

1968-01-01

Reward bands placed on the other leg of certain regularly banded immature mourning doves (Zenaidura macroura) were used to develop information on reporting rates of recovered dove bands. Reports from 15 widely separated sections of the United States showed considerable variation in recovery rate of doves both with and without reward bands. The overall percentages of banded doves that were reported as recovered were 9.69% for those with reward bands and 3.83% for controls. The bandreporting rate for states influenced by publicity was 66%; that for states not influenced was 32%.

Lifetime measurements in the picosecond range: Achievements and Perspectives

International Nuclear Information System (INIS)

Kruecken, Reiner

1999-01-01

This contribution will review the recoil distance method (RDM), its current range of applications as well as future perspectives for the measurement of lifetimes in the picosecond range of excited nuclear levels. Recent Doppler-shift lifetime experiments with large gamma-ray spectrometers have achieved a new level of precision and sensitivity, providing new insights into nuclear structure physics. High precision RDM measurements of near-yrast states in various mass regions have revealed dynamic shape effects beyond the framework of collective models and have also allowed to study the interaction between coexisting shapes. The measurement of lifetimes in superdeformed bands has shown that lifetimes can be measured for nuclear excitations, which are only populated with a few percent of the production cross-section of a nucleus. These experiments have also enabled us to study the mechanism of the decay-out of superdeformed bands. Another example for the need of precise lifetime measurements is the recent verifications of the concept of 'magnetic rotation' in nuclei by the experimental observation of the characteristic drop of B(M1) values as a function of angular momentum. These recent breakthroughs have also opened new perspectives for the use of the RDM technique for more exotic regions of nuclei and nuclear excitations. Here the measurement of lifetimes in neutron rich nuclei, which are not accessible with conventional nuclear reactions using stable beams and targets, is of special interest. Possible experimental approaches and simple estimates for the feasibility of such experiments will be presented. (author)

Opening the band gap of graphene through silicon doping for the improved performance of graphene/GaAs heterojunction solar cells

Science.gov (United States)

Zhang, S. J.; Lin, S. S.; Li, X. Q.; Liu, X. Y.; Wu, H. A.; Xu, W. L.; Wang, P.; Wu, Z. Q.; Zhong, H. K.; Xu, Z. J.

2015-12-01

Graphene has attracted increasing interest due to its remarkable properties. However, the zero band gap of monolayered graphene limits it's further electronic and optoelectronic applications. Herein, we have synthesized monolayered silicon-doped graphene (SiG) with large surface area using a chemical vapor deposition method. Raman and X-ray photoelectron spectroscopy measurements demonstrate that the silicon atoms are doped into graphene lattice at a doping level of 2.7-4.5 at%. Electrical measurements based on a field effect transistor indicate that the band gap of graphene has been opened via silicon doping without a clear degradation in carrier mobility, and the work function of SiG, deduced from ultraviolet photoelectron spectroscopy, was 0.13-0.25 eV larger than that of graphene. Moreover, when compared with the graphene/GaAs heterostructure, SiG/GaAs exhibits an enhanced performance. The performance of 3.4% silicon doped SiG/GaAs solar cell has been improved by 33.7% on average, which was attributed to the increased barrier height and improved interface quality. Our results suggest that silicon doping can effectively engineer the band gap of monolayered graphene and SiG has great potential in optoelectronic device applications.Graphene has attracted increasing interest due to its remarkable properties. However, the zero band gap of monolayered graphene limits it's further electronic and optoelectronic applications. Herein, we have synthesized monolayered silicon-doped graphene (SiG) with large surface area using a chemical vapor deposition method. Raman and X-ray photoelectron spectroscopy measurements demonstrate that the silicon atoms are doped into graphene lattice at a doping level of 2.7-4.5 at%. Electrical measurements based on a field effect transistor indicate that the band gap of graphene has been opened via silicon doping without a clear degradation in carrier mobility, and the work function of SiG, deduced from ultraviolet photoelectron

Deducing the kinetics of protein synthesis in vivo from the transition rates measured in vitro.

Directory of Open Access Journals (Sweden)

Sophia Rudorf

2014-10-01

Full Text Available The molecular machinery of life relies on complex multistep processes that involve numerous individual transitions, such as molecular association and dissociation steps, chemical reactions, and mechanical movements. The corresponding transition rates can be typically measured in vitro but not in vivo. Here, we develop a general method to deduce the in-vivo rates from their in-vitro values. The method has two basic components. First, we introduce the kinetic distance, a new concept by which we can quantitatively compare the kinetics of a multistep process in different environments. The kinetic distance depends logarithmically on the transition rates and can be interpreted in terms of the underlying free energy barriers. Second, we minimize the kinetic distance between the in-vitro and the in-vivo process, imposing the constraint that the deduced rates reproduce a known global property such as the overall in-vivo speed. In order to demonstrate the predictive power of our method, we apply it to protein synthesis by ribosomes, a key process of gene expression. We describe the latter process by a codon-specific Markov model with three reaction pathways, corresponding to the initial binding of cognate, near-cognate, and non-cognate tRNA, for which we determine all individual transition rates in vitro. We then predict the in-vivo rates by the constrained minimization procedure and validate these rates by three independent sets of in-vivo data, obtained for codon-dependent translation speeds, codon-specific translation dynamics, and missense error frequencies. In all cases, we find good agreement between theory and experiment without adjusting any fit parameter. The deduced in-vivo rates lead to smaller error frequencies than the known in-vitro rates, primarily by an improved initial selection of tRNA. The method introduced here is relatively simple from a computational point of view and can be applied to any biomolecular process, for which we have

On the influence of neutral turbulence on ambipolar diffusivities deduced from meteor trail expansion

Directory of Open Access Journals (Sweden)

C. M. Hall

2002-11-01

Full Text Available By measuring fading times of radar echoes from underdense meteor trails, it is possible to deduce the ambipolar diffusivities of the ions responsible for these radar echoes. It could be anticipated that these diffusivities increase monotonically with height akin to neutral viscosity. In practice, this is not always the case. Here, we investigate the capability of neutral turbulence to affect the meteor trail diffusion rate.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; turbulence

Mobility spectrum analytical approach for intrinsic band picture of Ba(FeAs)2

Science.gov (United States)

Huynh, K. K.; Tanabe, Y.; Urata, T.; Heguri, S.; Tanigaki, K.; Kida, T.; Hagiwara, M.

2014-09-01

Unconventional high temperature superconductivity as well as three-dimensional bulk Dirac cone quantum states arising from the unique d-orbital topology have comprised an intriguing research area in physics. Here we apply a special analytical approach using a mobility spectrum, in which the carrier number is conveniently described as a function of mobility without any hypothesis, both on the types and the numbers of carriers, for the interpretations of longitudinal and transverse electric transport of high quality single crystal Ba(FeAs)2 in a wide range of magnetic fields. We show that the majority carriers are accommodated in large parabolic hole and electron pockets with very different topology as well as remarkably different mobility spectra, whereas the minority carriers reside in Dirac quantum states with the largest mobility as high as 70,000 cm2(Vs)-1. The deduced mobility spectra are discussed and compared to the reported sophisticated first principle band calculations.

General Relativistic Mean Field Theory for rotating nuclei

Energy Technology Data Exchange (ETDEWEB)

Madokoro, Hideki [Kyushu Univ., Fukuoka (Japan). Dept. of Physics; Matsuzaki, Masayuki

1998-03-01

The {sigma}-{omega} model Lagrangian is generalized to an accelerated frame by using the technique of general relativity which is known as tetrad formalism. We apply this model to the description of rotating nuclei within the mean field approximation, which we call General Relativistic Mean Field Theory (GRMFT) for rotating nuclei. The resulting equations of motion coincide with those of Munich group whose formulation was not based on the general relativistic transformation property of the spinor fields. Some numerical results are shown for the yrast states of the Mg isotopes and the superdeformed rotational bands in the A {approx} 60 mass region. (author)

Vibrational motions in rotating nuclei studied by Coulomb excitations

Energy Technology Data Exchange (ETDEWEB)

Shimizu, Yoshifumi R [Kyushu Univ., Fukuoka (Japan). Dept. of Physics

1998-03-01

As is well-known Coulomb excitation is an excellent tool to study the nuclear collective motions. Especially the vibrational excitations in rotating nuclei, which are rather difficult to access by usual heavy-ion fusion reactions, can be investigated in detail. Combined with the famous 8{pi}-Spectrometer, which was one of the best {gamma}-ray detector and had discovered some of superdeformed bands, such Coulomb excitation experiments had been carried out at Chalk River laboratory just before it`s shutdown of physics division. In this meeting some of the experimental data are presented and compared with the results of theoretical investigations. (author)

Nuclear pairing reduction due to rotation and blocking

International Nuclear Information System (INIS)

Wu Xi; Zhang Zhenhua; Lei Yi'an; Zeng Jinyan

2010-01-01

Nuclear pairing gaps of well-deformed and superdeformed nuclei are investigated using the particle-number conserving (PNC) formalism for the cranked shell model, in which the blocking effects are treated exactly and no spurious states appear. Both the rotational frequency ω-dependence and seniority ν-dependence of the pairing gap Δ-bar are addressed. For the ground-state bands of even-even nuclei, PNC calculations show that in general Δ-bar decreases with increasing ω, but the ω-dependence is much weaker than that calculated by the number-projected Hartree-Fock-Bogolyubov (NHFB) approach. For the multi quasiparticle bands (seniority ν > 2), the pairing gaps keep almost ω-independent. As a function of the seniority ν, the bandhead pairing gaps Δ-bar (ν, ω = 0) decrease slowly with increasing ν. Even for the highest seniority ν bands identified so far, Δ-bar (ν, ω = 0) keep 70% larger than Δ-bar (ν = 0, ω = 0). (authors)

Nuclear pairing reduction due to rotation and blocking

International Nuclear Information System (INIS)

Wu, X.; Zhang, Z. H.; Zeng, J. Y.; Lei, Y. A.

2011-01-01

Nuclear pairing gaps of normally deformed and superdeformed nuclei are investigated using the particle-number-conserving (PNC) formalism for the cranked shell model, in which the blocking effects are treated exactly. Both rotational frequency ω dependence and seniority (number of unpaired particles) ν dependence of the pairing gap Δ-tilde are investigated. For the ground-state bands of even-even nuclei, PNC calculations show that, in general, Δ-tilde decreases with increasing ω, but the ω dependence is much weaker than that calculated by the number-projected Hartree-Fock-Bogolyubov approach. For the multiquasiparticle bands (seniority ν>2), the pairing gaps stay almost ω independent. As a function of the seniority ν, the bandhead pairing gaps Δ-tilde(ν,ω=0) decrease slowly with increasing ν. Even for the highest seniority ν bands identified so far, Δ-tilde(ν,ω=0) remains greater than 70% of Δ-tilde(ν=0,ω=0).

New features in the spectrum of {sup 152}Dy

Energy Technology Data Exchange (ETDEWEB)

Galindo-Uribarri, A; Andrews, H R; Ball, G C; Radford, D C; Janzen, V P; Ward, D [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Kuehner, J A; Mullins, S; Persson, L; Prevost, D; Waddington, J C [McMaster Univ., Hamilton, ON (Canada). Dept. of Physics; Drake, T E [Toronto Univ., ON (Canada). Dept. of Physics; Wyss, R [Joint Inst. for Heavy Ion Research, Oak Ridge, TN (United States)

1992-08-01

One of the most important recent developments in nuclear structure physics has been the prediction and observation of superdeformed (SD) shapes at high angular momentum in several nuclei in the rare earth region. The first experimental observation was a ridge-valley structure in a {gamma}-{gamma} coincidence matrix for the {sup 152}Dy nucleus. The ridge was found to be generated by sequences of stretched E2 transitions and corresponded to a moment of inertia J{sup (2)} of 85 {Dirac_h}{sup 2}MeV{sup -1}. Subsequently a discrete SD band was discovered in {sup 152}Dy and the lifetimes were measured. More recently the discovery of SD bands in several nuclei in the neighbourhood of {sup 152}Dy, the discovery of multiple SD bands in some nuclei, and the discovery of new SD regions at mass A {approx} 190 and A {approx} 140 have stimulated intense research activity in this area of nuclear physics. (author). 15 refs., 4 figs.

Improved spectral absorption coefficient grouping strategy of wide band k-distribution model used for calculation of infrared remote sensing signal of hot exhaust systems

Science.gov (United States)

Hu, Haiyang; Wang, Qiang

2018-07-01

A new strategy for grouping spectral absorption coefficients, considering the influences of both temperature and species mole ratio inhomogeneities on correlated-k characteristics of the spectra of gas mixtures, has been deduced to match the calculation method of spectral overlap parameter used in multiscale multigroup wide band k-distribution model. By comparison with current spectral absorption coefficient grouping strategies, for which only the influence of temperature inhomogeneity on the correlated-k characteristics of spectra of single species was considered, the improvements in calculation accuracies resulting from the new grouping strategy were evaluated using a series of 0D cases in which radiance under 3-5-μm wave band emitted by hot combustion gas of hydrocarbon fuel was attenuated by atmosphere with quite different temperature and mole ratios of water vapor and carbon monoxide to carbon dioxide. Finally, evaluations are presented on the calculation of remote sensing thermal images of transonic hot jet exhausted from a chevron ejecting nozzle with solid wall cooling system.

On the influence of neutral turbulence on ambipolar diffusivities deduced from meteor trail expansion

Directory of Open Access Journals (Sweden)

C. M. Hall

Full Text Available By measuring fading times of radar echoes from underdense meteor trails, it is possible to deduce the ambipolar diffusivities of the ions responsible for these radar echoes. It could be anticipated that these diffusivities increase monotonically with height akin to neutral viscosity. In practice, this is not always the case. Here, we investigate the capability of neutral turbulence to affect the meteor trail diffusion rate.

Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; turbulence

Dual-band frequency selective surface with large band separation and stable performance

Science.gov (United States)

Zhou, Hang; Qu, Shao-Bo; Peng, Wei-Dong; Lin, Bao-Qin; Wang, Jia-Fu; Ma, Hua; Zhang, Jie-Qiu; Bai, Peng; Wang, Xu-Hua; Xu, Zhuo

2012-05-01

A new technique of designing a dual-band frequency selective surface with large band separation is presented. This technique is based on a delicately designed topology of L- and Ku-band microwave filters. The two band-pass responses are generated by a capacitively-loaded square-loop frequency selective surface and an aperture-coupled frequency selective surface, respectively. A Faraday cage is located between the two frequency selective surface structures to eliminate undesired couplings. Based on this technique, a dual-band frequency selective surface with large band separation is designed, which possesses large band separation, high selectivity, and stable performance under various incident angles and different polarizations.

SHARPENDING OF THE VNIR AND SWIR BANDS OF THE WIDE BAND SPECTRAL IMAGER ONBOARD TIANGONG-II IMAGERY USING THE SELECTED BANDS

Directory of Open Access Journals (Sweden)

Q. Liu

2018-04-01

Full Text Available The Tiangong-II space lab was launched at the Jiuquan Satellite Launch Center of China on September 15, 2016. The Wide Band Spectral Imager (WBSI onboard the Tiangong-II has 14 visible and near-infrared (VNIR spectral bands covering the range from 403–990 nm and two shortwave infrared (SWIR bands covering the range from 1230–1250 nm and 1628–1652 nm respectively. In this paper the selected bands are proposed which aims at considering the closest spectral similarities between the VNIR with 100 m spatial resolution and SWIR bands with 200 m spatial resolution. The evaluation of Gram-Schmidt transform (GS sharpening techniques embedded in ENVI software is presented based on four types of the different low resolution pan band. The experimental results indicated that the VNIR band with higher CC value with the raw SWIR Band was selected, more texture information was injected the corresponding sharpened SWIR band image, and at that time another sharpened SWIR band image preserve the similar spectral and texture characteristics to the raw SWIR band image.

Dual-band frequency selective surface with large band separation and stable performance

International Nuclear Information System (INIS)

Zhou Hang; Qu Shao-Bo; Lin Bao-Qin; Wang Jia-Fu; Ma Hua; Zhang Jie-Qiu; Peng Wei-Dong; Bai Peng; Wang Xu-Hua; Xu Zhuo

2012-01-01

A new technique of designing a dual-band frequency selective surface with large band separation is presented. This technique is based on a delicately designed topology of L- and Ku-band microwave filters. The two band-pass responses are generated by a capacitively-loaded square-loop frequency selective surface and an aperture-coupled frequency selective surface, respectively. A Faraday cage is located between the two frequency selective surface structures to eliminate undesired couplings. Based on this technique, a dual-band frequency selective surface with large band separation is designed, which possesses large band separation, high selectivity, and stable performance under various incident angles and different polarizations. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

High-spin rotational states in {sup 179}Os

Energy Technology Data Exchange (ETDEWEB)

Burde, J [Lawrence Berkeley Lab., CA (United States); [Hebrew Univ., Jerusalem (Israel). Racah Inst. of Physics; Deleplanque, M A; Diamond, R M; Macchiavelli, A O; Stephens, F S; Beausang, C W [Lawrence Berkeley Lab., CA (United States)

1992-08-01

The rotational bands of the osmium isotopes display very interesting properties that vary with the neutron number. On the one hand the yrast bands of {sup 182,184,186}Os display a sudden and rather strong gain in aligned angular momentum,, whereas the lighter osmium nuclei such as {sup 176,178,180}Os show a more gradual increase of alignment characteristic of strongly interacting bands. In addition, an unusual rotational band has been found in {sup 178}Os. It consists of seven regularly spaced transitions about 36 keV apart which correspond closely to the spacing of the superdeformed band in {sup 152}Dy after an A{sup 5/3} normalization. this band populates the yrast band directly, and the moment of inertia J{sup (1)} is found to be much smaller than J{sup (2)}. The most likely interpretation of this is a band with large deformation which is undergoing systematic changes in deformation, pairing and/or alignment. This latter finding in particular motivated us to carry out research on the higher spin states in {sup 179}Os. Dracoulis et al. have published their results on 5 rotational bands in {sup 179}Os. In the present work we found six new bands and extended appreciably the spin limits in the other five. (author). 5 refs., 3 figs.

Nucleotide sequence of Phaseolus vulgaris L. alcohol dehydrogenase encoding cDNA and three-dimensional structure prediction of the deduced protein.

Science.gov (United States)

Amelia, Kassim; Khor, Chin Yin; Shah, Farida Habib; Bhore, Subhash J

2015-01-01

Common beans (Phaseolus vulgaris L.) are widely consumed as a source of proteins and natural products. However, its yield needs to be increased. In line with the agenda of Phaseomics (an international consortium), work of expressed sequence tags (ESTs) generation from bean pods was initiated. Altogether, 5972 ESTs have been isolated. Alcohol dehydrogenase (AD) encoding gene cDNA was a noticeable transcript among the generated ESTs. This AD is an important enzyme; therefore, to understand more about it this study was undertaken. The objective of this study was to elucidate P. vulgaris L. AD (PvAD) gene cDNA sequence and to predict the three-dimensional (3D) structure of deduced protein. positive and negative strands of the PvAD cDNA clone were sequenced using M13 forward and M13 reverse primers to elucidate the nucleotide sequence. Deduced PvAD cDNA and protein sequence was analyzed for their basic features using online bioinformatics tools. Sequence comparison was carried out using bl2seq program, and tree-view program was used to construct a phylogenetic tree. The secondary structures and 3D structure of PvAD protein were predicted by using the PHYRE automatic fold recognition server. The sequencing results analysis showed that PvAD cDNA is 1294 bp in length. It's open reading frame encodes for a protein that contains 371 amino acids. Deduced protein sequence analysis showed the presence of putative substrate binding, catalytic Zn binding, and NAD binding sites. Results indicate that the predicted 3D structure of PvAD protein is analogous to the experimentally determined crystal structure of s-nitrosoglutathione reductase from an Arabidopsis species. The 1294 bp long PvAD cDNA encodes for 371 amino acid long protein that contains conserved domains required for biological functions of AD. The predicted deduced PvAD protein's 3D structure reflects the analogy with the crystal structure of Arabidopsis thaliana s-nitrosoglutathione reductase. Further study is required

Band structure of semiconductors

CERN Document Server

Tsidilkovski, I M

2013-01-01

Band Structure of Semiconductors provides a review of the theoretical and experimental methods of investigating band structure and an analysis of the results of the developments in this field. The book presents the problems, methods, and applications in the study of band structure. Topics on the computational methods of band structure; band structures of important semiconducting materials; behavior of an electron in a perturbed periodic field; effective masses and g-factors for the most commonly encountered band structures; and the treatment of cyclotron resonance, Shubnikov-de Haas oscillatio

Global significance of a sub-Moho boundary layer (SMBL) deduced from high-resolution seismic observations

Science.gov (United States)

Fuchs, K.; Tittgemeyer, M.; Ryberg, T.; Wenzel, F.; Mooney, W.

2002-01-01

We infer the fine structure of a sub-Moho boundary layer (SMBL) at the top of the lithospheric mantle from high-resolution seismic observations of Peaceful Nuclear Explosions (PNE) on superlong-range profiles in Russia. Densely recorded seismograms permit recognition of previously unknown features of teleseismic propagation of the well known Pn and Sn phases, such as a band of incoherent, scattered, high-frequency seismic energy, developing consistently from station to station, apparent velocities of sub-Moho material, and high-frequency energy to distances of more than 3000 km with a coda band, incoherent at 10 km spacing and yet consistently observed to the end of the profiles. Estimates of the other key elements of the SMBL were obtained by finite difference calculations of wave propagation in elastic 2D models from a systematic grid search through parameter space. The SMBL consists of randomly distributed, mild velocity fluctuations of 2% or schlieren of high aspect ratios (???40) with long horizontal extent (???20 km) and therefore as thin as 0.5 km only; SMBL thickness is 60-100 km. It is suggested that the SMBL is of global significance as the physical base of the platewide observed high-frequency phases Pn and Sn. It is shown that wave propagation in the SMBL waveguide is insensitive to the background velocity distribution on which its schlieren are superimposed. This explains why the Pn and Sn phases traverse geological provinces of various age, heat flow, crustal thickness, and tectonic regimes. Their propagation appears to be independent of age. temperature, pressure, and stress. Dynamic stretching of mantle material during subduction or flow, possibly combined with chemical differentiation have to be considered as scale-forming processes in the upper mantle. However, it is difficult to distinguish with the present sets of Pn/Sn array data whether (and also where) the boundary layer is a frozen-in feature of paleo-processes or whether it is a response to

Red-luminescence band: A tool for the quality assessment of germanium and silicon nanocrystals

Science.gov (United States)

Fraj, I.; Favre, L.; David, T.; Abbarchi, M.; Liu, K.; Claude, J. B.; Ronda, A.; Naffouti, M.; Saidi, F.; Hassen, F.; Maaref, H.; Aqua, J. N.; Berbezier, I.

2017-10-01

We present the photoluminescence (PL) emission of Silicon and Germanium nanocrystals (NCs) of different sizes embedded in two different matrices. Formation of the NCs is achieved via solid-state dewetting during annealing in a molecular beam epitaxy ultra-high vacuum system of ultrathin amorphous Si and Ge layers deposited at room temperature on SiO2. During the dewetting process, the bi-dimensional amorphous layers transform into small pseudo-spherical islands whose mean size can be tuned directly with the deposited thickness. The nanocrystals are capped either ex situ by silicon dioxide or in situ by amorphous Silicon. The surface-state dependent emission (typically in the range 1.74 eV-1.79 eV) exhibited higher relative PL quantum yields compared to the emission originating from the band gap transition. This red-PL emission comes from the radiative transitions between a Si band and an interface level. It is mainly ascribed to the NCs and environment features deduced from morphological and structural analyses. Power dependent analysis of the photoluminescence intensity under continuous excitation reveals a conventional power law with an exponent close to 1, in agreement with the type II nature of the emission. We show that Ge-NCs exhibit much lower quantum efficiency than Si-NCs due to non-radiative interface states. Low quantum efficiency is also obtained when NCs have been exposed to air before capping, even if the exposure time is very short. Our results indicate that a reduction of the non-radiative surface states is a key strategy step in producing small NCs with increased PL emission for a variety of applications. The red-PL band is then an effective tool for the quality assessment of NCs based structures.

Atomic-Monolayer MoS2 Band-to-Band Tunneling Field-Effect Transistor

KAUST Repository

Lan, Yann Wen

2016-09-05

The experimental observation of band-to-band tunneling in novel tunneling field-effect transistors utilizing a monolayer of MoS2 as the conducting channel is demonstrated. Our results indicate that the strong gate-coupling efficiency enabled by two-dimensional materials, such as monolayer MoS2, results in the direct manifestation of a band-to-band tunneling current and an ambipolar transport.

Comparison of UV action spectra for lethality and mutation in Salmonella typhimurium using a broad band source and monochromatic radiations

International Nuclear Information System (INIS)

Calkins, John; Selby, Christopher; Enoch, H.G.

1987-01-01

The UV-B region (280-320 nm) is thought to be primarily responsible for the mutagenic, lethal, and carcinogenic effects of solar radiation. We have conducted UV-B action spectroscopy for mutagenesis and survival of Ames' Salmonella typhimurium strain TA98 (uvrB, pKM101) using both monochromatic radiation from a dye laser and broader bandwidth radiation emitted from FS-20 sunlamps. A series of optical filters having different transmission cut-offs together with the sunlamp source provided bandwidths having successively less short wavelength components from which a ''broad band'' action spectrum was deduced. The two sets of action spectra differed both qualitatively and quantitatively: in comparison to the monochromatic action spectra, the ''broad band'' spectra showed up to a 200-fold reduced efficiency for both mutation induction and lethality by UV-B wavelengths. These results suggest a large protective effect of the background UV-A and/or visible radiations which were present during the broad spectrum irradiations and which are also present in solar radiation. Additional experiments show that to the extent tested this protective effect is not due to photo-reactivation or irradiance (dose rate) effects. (author)

Anomaly in the P- and R- branches in the spectra of hydrogen Fulcher band emission

International Nuclear Information System (INIS)

Kado, Shinichiro; Yamasaki, Daisuke; Iida, Yohei; Xiao Bingjia

2004-01-01

Anomalies in the Fulcher-band (d 3 Π u -a 3 Σ g + ) spectra, which are widely used for the purpose of measuring ro-vibronic structure of the hydrogen molecule, are investigated using the hollow cathode glow discharge of 230 V-70 mA at 30 Pa. By making use of the recently developed analyzing scheme and experimentally determined life-time of the state involved, the historical data in the Ginsburg and Dieke's publication are reanalyzed and compared with our present data. Populations of the vibronic state v' ≥ 4 in the Q branch can be corrected to a considerable extend by taking into account the lifetime of the states, while those of any v' in the P and R branches cannot. However, the average values of the upper-Fulcher populations deduced from the P and R branches coincide with those from Q branch by taking into consideration the difference in the excitation from the ground electronic state. (author)

Band-notched spiral antenna

Science.gov (United States)

Jeon, Jae; Chang, John

2018-03-13

A band-notched spiral antenna having one or more spiral arms extending from a radially inner end to a radially outer end for transmitting or receiving electromagnetic radiation over a frequency range, and one or more resonance structures positioned adjacent one or more segments of the spiral arm associated with a notch frequency band or bands of the frequency range so as to resonate and suppress the transmission or reception of electromagnetic radiation over said notch frequency band or bands.

Extreme nuclear deformations studied at the GASP spectrometer

International Nuclear Information System (INIS)

Lunardi, S.; Bazzacco, D.; Fabris, D.; Lunardon, M.; Medina, N.H.; Nebbia, G.; Petrache, C.M.; Rizzuto, M.A.; Alvarez, C.R.; Viesti, G.

1997-01-01

Very exotic shapes can be assumed for the nuclei at high angular momenta. Their study has become possible with the advent of the last generation high-resolution γ-ray spectrometers. In this talk results are presented on superdeformed nuclei of the A = 140 mass region where a detailed spectroscopy in the second minimum is now possible. Hyperdeformed rotational bands, expected in the third minimum, lie at even higher spins where their observation is very difficult from the experimental point of view. Up to now only weak signals of their presence have been observed. The status of the search for hyperdeformation in 152 Dy is reported. (author)

Measurement of core level and band offsets at the interface of ITO/Hg_3In_2Te_6(1 1 0) heterojunction by synchrotron radiation photoelectron spectroscopy

International Nuclear Information System (INIS)

Li, Yapeng; Fu, Li; Sun, Jie; Ibrahim, Kurash; Wang, Jia-ou

2016-01-01

Highlights: • The valence band maximum of ITO film and MIT were measured to be 1.6 eV and 0.6 eV, respectively. • The concentration of In element presented a trend of increasing first and then decreasing from MIT to ITO. • The valence band offsets of the ITO/MIT(1 1 0) heterojunction was confirmed to be a type-II band alignment phenomenon. - Abstract: The Indium Tin Oxide (ITO) film was deposited on the surface of Hg_3In_2Te_6 (short for MIT) (1 1 0) for the fabrication of ITO/MIT(1 1 0) heterojunction by using the pulsed laser deposition method. In situ X-ray photoelectron spectroscopy was utilized to examine the band offsets and core level of ITO/MIT(1 1 0) heterojunctions. The result showed that the valence band maximum of ITO films and MIT(1 1 0) were 1.6 eV and 0.6 eV, respectively. Meanwhile, it was found that the binding energy of Te 3d, Sn 3d and Hg 4f remained unchanged during the ITO deposition process. However, the binding energy of O 1s and In 3d_5_/_2 increased about 0.3 eV and 0.2 eV, respectively, with the thickness increasing of ITO film from 3.5 nm to 5 nm. This may due to the elements diffusion at the interface region during the film growing process. According to the core level spectrum, it can be speculated that no significant chemical reaction occurred at the interface of ITO/MIT(1 1 0). In addition, the valence band offset of the ITO/MIT(1 1 0) heterojunction can be calculated to be −1 ± 0.15 eV by the means of the photoelectron spectroscopy methods. The conduction band offset is deduced to be −3.96 ± 0.15 eV from the known valence band offset value, indicating that the band offsets of ITO/MIT(1 1 0) heterojunction is a type-II band alignment.

Coronal mass ejection kinematics deduced from white light (Solar Mass Ejection Imager) and radio (Wind/WAVES) observations

Science.gov (United States)

Reiner, M. J.; Jackson, B. V.; Webb, D. F.; Mizuno, D. R.; Kaiser, M. L.; Bougeret, J.-L.

2005-09-01

White-light and radio observations are combined to deduce the coronal and interplanetary kinematics of a fast coronal mass ejection (CME) that was ejected from the Sun at about 1700 UT on 2 November 2003. The CME, which was associated with an X8.3 solar flare from W56°, was observed by the Mauna Loa and Solar and Heliospheric Observatory (SOHO) Large-Angle Spectrometric Coronograph (LASCO) coronagraphs to 14 R⊙. The measured plane-of-sky speed of the LASCO CME was 2600 km s-1. To deduce the kinematics of this CME, we use the plane-of-sky white light observations from both the Solar Mass Ejection Imager (SMEI) all-sky camera on board the Coriolis spacecraft and the SOHO/LASCO coronagraph, as well as the frequency drift rate of the low-frequency radio data and the results of the radio direction-finding analysis from the WAVES experiment on the Wind spacecraft. In agreement with the in situ observations for this event, we find that both the white light and radio observations indicate that the CME must have decelerated significantly beginning near the Sun and continuing well into the interplanetary medium. More specifically, by requiring self-consistency of all the available remote and in situ data, together with a simple, but not unreasonable, assumption about the general characteristic of the CME deceleration, we were able to deduce the radial speed and distance time profiles for this CME as it propagated from the Sun to 1 AU. The technique presented here, which is applicable to mutual SMEI/WAVES CME events, is expected to provide a more complete description and better quantitative understanding of how CMEs propagate through interplanetary space, as well as how the radio emissions, generated by propagating CME/shocks, relate to the shock and CME. This understanding can potentially lead to more accurate predictions for the onset times of space weather events, such as those that were observed during this unique period of intense solar activity.

Intrinsic neutrino properties: As deduced from cosmology, astrophysics, accelerator and non-accelerator experiments

International Nuclear Information System (INIS)

Rosen, S.P.

1990-01-01

I review the intrinsic properties of neutrinos as deduced from cosmological, astrophysical, and laboratory experiments. Bounds on magnetic moments and theoretical models which yield large moments but small masses are briefly discussed. The MSW solution to the solar neutrino problem is reviewed in light of the existing data from the 37 Cl and Kamiokande II experiments. The combined data disfavor the adiabatic solution and tend to support either the large angle solution or the nonadiabatic one. In the former case the 71 Ga signal will be suppressed by the same factor as for 37 Cl, and in the latter case the suppression factor could be as large as 10 or more. 41 refs

Congenital Constriction Band Syndrome

OpenAIRE

Rajesh Gupta, Fareed Malik, Rishabh Gupta, M.A.Basit, Dara Singh

2008-01-01

Congenital constriction bands are anomalous bands that encircle a digit or an extremity. Congenitalconstriction band syndrome is rare condition and is mostly associated with other musculoskeletaldisorders.We report such a rare experience.

Single-Band and Dual-Band Infrared Detectors

Science.gov (United States)

Ting, David Z. (Inventor); Gunapala, Sarath D. (Inventor); Soibel, Alexander (Inventor); Nguyen, Jean (Inventor); Khoshakhlagh, Arezou (Inventor)

2017-01-01

Bias-switchable dual-band infrared detectors and methods of manufacturing such detectors are provided. The infrared detectors are based on a back-to-back heterojunction diode design, where the detector structure consists of, sequentially, a top contact layer, a unipolar hole barrier layer, an absorber layer, a unipolar electron barrier, a second absorber, a second unipolar hole barrier, and a bottom contact layer. In addition, by substantially reducing the width of one of the absorber layers, a single-band infrared detector can also be formed.

Modular design, application architecture, and usage of a self-service model for enterprise data delivery: The Duke Enterprise Data Unified Content Explorer (DEDUCE)

Science.gov (United States)

Horvath, Monica M.; Rusincovitch, Shelley A.; Brinson, Stephanie; Shang, Howard C.; Evans, Steve; Ferranti, Jeffrey M.

2015-01-01

Purpose Data generated in the care of patients are widely used to support clinical research and quality improvement, which has hastened the development of self-service query tools. User interface design for such tools, execution of query activity, and underlying application architecture have not been widely reported, and existing tools reflect a wide heterogeneity of methods and technical frameworks. We describe the design, application architecture, and use of a self-service model for enterprise data delivery within Duke Medicine. Methods Our query platform, the Duke Enterprise Data Unified Content Explorer (DEDUCE), supports enhanced data exploration, cohort identification, and data extraction from our enterprise data warehouse (EDW) using a series of modular environments that interact with a central keystone module, Cohort Manager (CM). A data-driven application architecture is implemented through three components: an application data dictionary, the concept of “smart dimensions”, and dynamically-generated user interfaces. Results DEDUCE CM allows flexible hierarchies of EDW queries within a grid-like workspace. A cohort “join” functionality allows switching between filters based on criteria occurring within or across patient encounters. To date, 674 users have been trained and activated in DEDUCE, and logon activity shows a steady increase, with variability between months. A comparison of filter conditions and export criteria shows that these activities have different patterns of usage across subject areas. Conclusions Organizations with sophisticated EDWs may find that users benefit from development of advanced query functionality, complimentary to the user interfaces and infrastructure used in other well-published models. Driven by its EDW context, the DEDUCE application architecture was also designed to be responsive to source data and to allow modification through alterations in metadata rather than programming, allowing an agile response to source

Modular design, application architecture, and usage of a self-service model for enterprise data delivery: the Duke Enterprise Data Unified Content Explorer (DEDUCE).

Science.gov (United States)

Horvath, Monica M; Rusincovitch, Shelley A; Brinson, Stephanie; Shang, Howard C; Evans, Steve; Ferranti, Jeffrey M

2014-12-01

Data generated in the care of patients are widely used to support clinical research and quality improvement, which has hastened the development of self-service query tools. User interface design for such tools, execution of query activity, and underlying application architecture have not been widely reported, and existing tools reflect a wide heterogeneity of methods and technical frameworks. We describe the design, application architecture, and use of a self-service model for enterprise data delivery within Duke Medicine. Our query platform, the Duke Enterprise Data Unified Content Explorer (DEDUCE), supports enhanced data exploration, cohort identification, and data extraction from our enterprise data warehouse (EDW) using a series of modular environments that interact with a central keystone module, Cohort Manager (CM). A data-driven application architecture is implemented through three components: an application data dictionary, the concept of "smart dimensions", and dynamically-generated user interfaces. DEDUCE CM allows flexible hierarchies of EDW queries within a grid-like workspace. A cohort "join" functionality allows switching between filters based on criteria occurring within or across patient encounters. To date, 674 users have been trained and activated in DEDUCE, and logon activity shows a steady increase, with variability between months. A comparison of filter conditions and export criteria shows that these activities have different patterns of usage across subject areas. Organizations with sophisticated EDWs may find that users benefit from development of advanced query functionality, complimentary to the user interfaces and infrastructure used in other well-published models. Driven by its EDW context, the DEDUCE application architecture was also designed to be responsive to source data and to allow modification through alterations in metadata rather than programming, allowing an agile response to source system changes. Copyright © 2014 Elsevier

Nuclear structure models: Applications and development. Progress report, May 1, 1993--June 30, 1994

International Nuclear Information System (INIS)

Semmes, P.B.

1994-06-01

This report summarizes the progress made during the period May 1, 1993 through June 30, 1994 on Grant No. DE-FG05-92ER40694. Our calculations of M1 transition rates within rotational bands of superdeformed nuclei have been extended to 2-quasiparticle states (mainly for odd-odd nuclei) in the A ∼ 190 region. Several bands are predicted with large B(MI) values and suggest that the MI properties can give information on details of occupied single particle orbitals, alignment of some high-N particles and the residual two-body interactions at extreme deformation. Detailed calculations and comparison with UNISOR data for the low energy, low spin structure of 187 Au have revealed two coexisting prolate structures built on the π[h 9/2 + f 7/2 ] configuration. This result was completely unexpected and presents strong challenges to our understanding of shape coexistence

Very extended shpaes in the A ∼ 150 mass region

International Nuclear Information System (INIS)

Chasman, R.R.

1995-01-01

There was a report of a rotational band in 152 Dy or 153 Dy that is characterized by a dynamic moment of inertia of 130h 2 MeV -1 . For purposes of orientation, it should be noted that the well known superdeformed bands in this region are characterized by moments of inertia of ∼90. Some calculations were carried out in two- and three-dimensional shape spaces, in order to understand this experimental observation. These calculations show either very shallow minima and/or minima that do not become yrast below I = 90 at the very large deformations that would seem to be required to explain such a large moment of inertia. We extended our four-dimensional deformation space Strutinsky calculations to a study of this mass region, with the hope of gaining some insight into the nature of this band. We are also analyzing the other nuclides of this mass region with the hope of finding other instances of such very extended shapes. This analysis is almost complete

Band Edge Dynamics and Multiexciton Generation in Narrow Band Gap HgTe Nanocrystals.

Science.gov (United States)

Livache, Clément; Goubet, Nicolas; Martinez, Bertille; Jagtap, Amardeep; Qu, Junling; Ithurria, Sandrine; Silly, Mathieu G; Dubertret, Benoit; Lhuillier, Emmanuel

2018-04-11

Mercury chalcogenide nanocrystals and especially HgTe appear as an interesting platform for the design of low cost mid-infrared (mid-IR) detectors. Nevertheless, their electronic structure and transport properties remain poorly understood, and some critical aspects such as the carrier relaxation dynamics at the band edge have been pushed under the rug. Some of the previous reports on dynamics are setup-limited, and all of them have been obtained using photon energy far above the band edge. These observations raise two main questions: (i) what are the carrier dynamics at the band edge and (ii) should we expect some additional effect (multiexciton generation (MEG)) as such narrow band gap materials are excited far above the band edge? To answer these questions, we developed a high-bandwidth setup that allows us to understand and compare the carrier dynamics resonantly pumped at the band edge in the mid-IR and far above the band edge. We demonstrate that fast (>50 MHz) photoresponse can be obtained even in the mid-IR and that MEG is occurring in HgTe nanocrystal arrays with a threshold around 3 times the band edge energy. Furthermore, the photoresponse can be effectively tuned in magnitude and sign using a phototransistor configuration.

Noise exposure in marching bands

Science.gov (United States)

Keefe, Joseph

2005-09-01

Previous studies involving orchestras have shown that music ensembles can produce hazardous noise levels. There are no similar data for marching bands and pep bands. In order to evaluate the noise levels produced by marching and pep bands, 1/3-octave-band sound-pressure levels were measured while these groups rehearsed and performed. Data were collected while marching with the bands to ensure a realistic environment. Comparing these data to OSHA and NIOSH criteria, marching and pep band exposures often exceed safe values. For typical exposures, OSHA doses range from 11% to 295%, while NIOSH doses range from 35% to 3055%. Exposures that would be considered hazardous in the workplace are common in marching and pep bands; students and band directors should take steps to recognize the risk posed by various instruments and various locations, and should implement hearing conservation efforts.

Deducing the pathogenic contribution of recessive ABCA4 alleles in an outbred population.

Science.gov (United States)

Schindler, Emily I; Nylen, Erik L; Ko, Audrey C; Affatigato, Louisa M; Heggen, Andrew C; Wang, Kai; Sheffield, Val C; Stone, Edwin M

2010-10-01

Accurate prediction of the pathogenic effects of specific genotypes is important for the design and execution of clinical trials as well as for meaningful counseling of individual patients. However, for many autosomal recessive diseases, it can be difficult to deduce the relative pathogenic contribution of individual alleles because relatively few affected individuals share the same two disease-causing variations. In this study, we used multiple regression analysis to estimate the pathogenicity of specific alleles of ABCA4 in patients with retinal phenotypes ranging from Stargardt disease to retinitis pigmentosa. This analysis revealed quantitative allelic effects on two aspects of the visual phenotype, visual acuity (P disease and will also aid in the optimal selection of subjects for clinical trials of new therapies.

B(M1) values in the band-crossing of shears bands in 197Pb

Science.gov (United States)

Krücken, R.; Cooper, J. R.; Beausang, C. W.; Novak, J. R.; Dewald, A.; Klug, T.; Kemper, G.; von Brentano, P.; Carpenter, M.; Wiedenhöver, I.

We present details of the band crossing mechanism of shears bands using the example of 197Pb. Absolute reduced matrix elements B(M1) were determined by means of a RDM lifetime measurement in one of the shears bands in 197Pb. The experiment was performed using the New Yale Plunger Device (NYPD) in conjunction with the Gammasphere array. Band mixing calculations on the basis of the semi-classical model of the shears mechanism are used to describe the transition matrix elements B(M1) and energies throughout the band-crossing regions. Good agreement with the data was obtained and the detailed composition of the states in the shears band are discussed.

Precipitation Estimation Using L-Band and C-Band Soil Moisture Retrievals

Science.gov (United States)

Koster, Randal D.; Brocca, Luca; Crow, Wade T.; Burgin, Mariko S.; De Lannoy, Gabrielle J. M.

2016-01-01

An established methodology for estimating precipitation amounts from satellite-based soil moisture retrievals is applied to L-band products from the Soil Moisture Active Passive (SMAP) and Soil Moisture and Ocean Salinity (SMOS) satellite missions and to a C-band product from the Advanced Scatterometer (ASCAT) mission. The precipitation estimates so obtained are evaluated against in situ (gauge-based) precipitation observations from across the globe. The precipitation estimation skill achieved using the L-band SMAP and SMOS data sets is higher than that obtained with the C-band product, as might be expected given that L-band is sensitive to a thicker layer of soil and thereby provides more information on the response of soil moisture to precipitation. The square of the correlation coefficient between the SMAP-based precipitation estimates and the observations (for aggregations to approximately100 km and 5 days) is on average about 0.6 in areas of high rain gauge density. Satellite missions specifically designed to monitor soil moisture thus do provide significant information on precipitation variability, information that could contribute to efforts in global precipitation estimation.

ISM band to U-NII band frequency transverter and method of frequency transversion

Science.gov (United States)

Stepp, Jeffrey David [Grandview, MO; Hensley, Dale [Grandview, MO

2006-09-12

A frequency transverter (10) and method for enabling bi-frequency dual-directional transfer of digitally encoded data on an RF carrier by translating between a crowded or otherwise undesirable first frequency band, such as the 2.4 GHz ISM band, and a less-crowded or otherwise desirable second frequency band, such as the 5.0 GHz 6.0 GHz U-NII band. In a preferred embodiment, the transverter (10) connects between an existing data radio (11) and its existing antenna (30), and comprises a bandswitch (12); an input RF isolating device (14); a transmuter (16); a converter (18); a dual output local oscillator (20); an output RF isolating device (22); and an antenna (24) tuned to the second frequency band. The bandswitch (12) allows for bypassing the transverter (10), thereby facilitating its use with legacy systems. The transmuter (14) and converter (16) are adapted to convert to and from, respectively, the second frequency band.

Dotaciones para la recuperación de activos revertibles como deducibles del impuesto sobre sociedades

OpenAIRE

Duplá Marín, María José

2001-01-01

El objetivo final que nos propusimos con este trabajo de investigación fue profundizar en el estudio jurídico-tributario de las dotaciones al fondo de reversión como gasto deducible para determinar la base imponible del impuesto sobre sociedades, en aquellas sociedades concesionarias de servicios públicos con cláusula de reversión de activos, partiendo de su realidad contable.En consecuencia el trabajo se ciñe al estudio crítico de la regulación jurídica del fondo de reversión como gasto fisc...

Design of a side-band-separating heterodyne mixer for band 9 of ALMA

NARCIS (Netherlands)

Baryshev, AM; Kooi, J; Mena, FR; Lodewijk, CRJ; Wild, W

2005-01-01

A side-band-separating (SBS) heterodyne mixer has been designed for the Atacama Large Millimeter Array (ALMA) 602-720 GHz band, as it will present a great improvement over the current double-side-band configuration under development at the moment. Here we present design details and the results of

Collapse and revival in inter-band oscillations of a two-band Bose-Hubbard model

Energy Technology Data Exchange (ETDEWEB)

Ploetz, Patrick; Wimberger, Sandro [Institut fuer Theoretische Physik, Universitaet Heidelberg, Philosophenweg 19, 69120 Heidelberg (Germany); Madronero, Javier, E-mail: ploetz@thphys.uni-heidelberg.d [Physik Department, Technische Universitaet Muenchen, James-Franck-Str. 1, 85748 Garching (Germany)

2010-04-28

We study the effect of a many-body interaction on inter-band oscillations in a two-band Bose-Hubbard model with an external Stark force. Weak and strong inter-band oscillations are observed, where the latter arise from a resonant coupling of the bands. These oscillations collapse and revive due to a weak two-body interaction between the atoms. Effective models for oscillations in and out of resonance are introduced that provide predictions for the system's behaviour, particularly for the time scales for the collapse and revival of the resonant inter-band oscillations. (fast track communication)

Side-band-separating heterodyne mixer for band 9 of ALMA.

NARCIS (Netherlands)

Mena, F. P.; Baryshev, A. M.; Kooi, J.; Lodewijk, C. F. J.; Gerlofsma, G.; Hesper, R.; Wild, W.; Shen, XC; Lu, W; Zhang, J; Dou, WB

2006-01-01

Here we present the realization of a side-band-separating (2SB) heterodyne mixer for the frequency range from 602 to 720 GHz (corresponding to ALMA band 9). The mixer, in brief, consists of a quadrature hybrid, two LO injectors, two SIS junctions, and three dumping loads. All the parts were modeled

Exciton spectra and energy band structure of Cu{sub 2}ZnSiSe{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Guc, M., E-mail: gmax@phys.asm.md [Institute of Applied Physics, Academy of Sciences of Moldova, Academiei Str. 5, Chisinau MD 2028, Republic of Moldova (Moldova, Republic of); Levcenko, S. [Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Dermenji, L. [Institute of Applied Physics, Academy of Sciences of Moldova, Academiei Str. 5, Chisinau MD 2028, Republic of Moldova (Moldova, Republic of); Gurieva, G. [Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Schorr, S. [Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Free University Berlin, Institute of Geological Sciences, Malteserstr. 74-100, Berlin (Germany); Syrbu, N.N. [Technical University of Moldova, Chisinau MD-2004, Republic of Moldova (Moldova, Republic of); Arushanov, E. [Institute of Applied Physics, Academy of Sciences of Moldova, Academiei Str. 5, Chisinau MD 2028, Republic of Moldova (Moldova, Republic of)

2014-02-25

Highlights: • Reflection spectra of Cu{sub 2}ZnSiSe{sub 4} were studied for E ⊥ c and E || c light polarizations. • Four excitonic series are revealed in the reflection spectra at 10 K. • Model of exciton dispersion and the presence of a dead-layer. • Exciton Rydberg energies and free carriers effective masses were calculated. • Reflectivity for E ⊥ c and E || c were analyzed in the region 3–6 eV at 300 K. -- Abstract: Exciton spectra are studied in Cu{sub 2}ZnSiSe{sub 4} single crystals at 10 and 300 K by means of reflection spectroscopy. The exciton parameters, dielectric constant and free carriers effective masses are deduced from experimental spectra by calculations in the framework of a model taking into account the spatial dispersion and the presence of a dead-layer. The structure found in the reflectivity was analyzed and related to the theoretical electronic band structure of close related Cu{sub 2}ZnSiS{sub 4} semiconductor.

The DSS-14 C-band exciter

Science.gov (United States)

Rowan, D. R.

1989-01-01

The development and implementation of a C-band exciter for use with the Block IV Receiver-Exciter Subsystem at Deep Space Station 14 (DSS-14) has been completed. The exciter supplements the standard capabilities of the Block IV system by providing a drive signal for the C-band transmitter while generating coherent translation frequencies for C-band (5-GHz) to S-band (2.2- to 2.3-GHz) Doppler extraction, C-band to L-band (1.6-GHz) zero delay measurements, and a level calibrated L-band test signal. Exciter functions are described, and a general explanation and description of the C-band uplink controller is presented.

Transport in bilayer and trilayer graphene: band gap engineering and band structure tuning

Science.gov (United States)

Zhu, Jun

2014-03-01

Controlling the stacking order of atomically thin 2D materials offers a powerful tool to control their properties. Linearly dispersed bands become hyperbolic in Bernal (AB) stacked bilayer graphene (BLG). Both Bernal (ABA) and rhombohedral (ABC) stacking occur in trilayer graphene (TLG), producing distinct band structures and electronic properties. A symmetry-breaking electric field perpendicular to the sample plane can further modify the band structures of BLG and TLG. In this talk, I will describe our experimental effort in these directions using dual-gated devices. Using thin HfO2 film deposited by ALD as gate dielectric, we are able to apply large displacement fields D > 6 V/nm and observe the opening and saturation of the field-induced band gap Eg in bilayer and ABC-stacked trilayer graphene, where the conduction in the mid gap changes by more than six decades. Its field and temperature dependence highlights the crucial role played by Coulomb disorder in facilitating hopping conduction and suppressing the effect of Eg in the tens of meV regime. In contrast, mid-gap conduction decreases with increasing D much more rapidly in clean h-BN dual-gated devices. Our studies also show the evolution of the band structure in ABA-stacked TLG, in particular the splitting of the Dirac-like bands in large D field and the signatures of two-band transport at high carrier densities. Comparison to theory reveals the need for more sophisticated treatment of electronic screening beyond self-consistent Hartree calculations to accurately predict the band structures of trilayer graphene and graphenic materials in general.

Advances in X-Band and S-Band Linear Accelerators for Security, NDT, and Other Applications

CERN Document Server

Mishin, Andrey V

2005-01-01

At AS&E High Energy Systems Division, we designed several new advanced high energy electron beam and X-ray sources. Our primary focus has always been in building the world's most portable commercial X-band accelerators. Today, our X-band systems frequently exceed performance of the similar S-band machines, while they are more portable compared to the latter. The new designs of the X-band accelerators in the most practical energy range from 1 MeV to 6 MeV have been tested delivering outstanding results. Seventy 6 MeV X-band linacs systems have been produced. The most compact linac for security is used by AS&E in a self-shielded, Shaped Energy™ cargo screening system. We pioneered using the X-band linear accelerators for CT, producing high quality images of oil pipes and wood logs. An X-band linear accelerator head on a robotic arm has been used for electron beam radiation curing of an odd-shaped graphite composite part. We developed the broad-range 4 MeV to over 10 MeV energy-regulated X-band ...

Identification of Nilsson orbitals in the superdeformed minimum of 237Pu

International Nuclear Information System (INIS)

Morgan, Thomas James

2008-01-01

In this thesis, a spectroscopy experiment in the second minimum of the double humped fission barrier of 237 Pu is presented, in which, for the first time, single - particle states for a neutron - rich shape isomer with odd neutron number were identified and characterised by their Nilsson quantum numbers. While rotational ( 236f U and 240f Pu) and vibrational excitations ( 240f Pu) had already been identified earlier in the even-even neighbouring nuclei, now the fission isomers in 237 Pu (t 1/2 =115 ns/1.12 μs) were investigated in a γ-spectroscopy experiment at the Cologne Tandem accelerator. Using the 235 U(α,2n) reaction with a pulsed R beam, states in the second minimum were populated. Following the prompt decay of excited states into the ground states of the two shape isomers, the nucleus decays with its halflife, the resulting fission fragments were detected in a specially built 4π parallel plate detector. The extremely rare isomeric γ decays were measured in coincidence with the fission fragments using the highly efficient MINIBALL spectrometer. The background-subtracted γ-ray spectrum was disentangled into contributions from the two shape isomers and 9 excited rotational bands were identified built on the ground states of the two isomers. The ground state spins of the two shape isomers were determined to be I=5/2 (115 ns isomer) and I=9/2 (1120 ns isomer). From the 149 identified γ transitions, independent level schemes were constructed for the two fission isomers in 237 Pu. The consistency of these level schemes was supported by the connecting γ transitions between rotational bands. Furthermore, both level schemes could be combined to a common level scheme, in which the ground state of the long-lived 9/2 isomer was placed 54.0(3) keV above the ground state of the short-lived 5/2 isomer. The resulting level scheme was compared to Hartree-Fock-Bogolyubov single-particle calculations, Nilsson model and Woods-Saxon potential calculations. This

Band gap and band offset of (GaIn)(PSb) lattice matched to InP

Science.gov (United States)

Köhler, F.; Böhm, G.; Meyer, R.; Amann, M.-C.

2005-07-01

Metastable (GaxIn1-x)(PySb1-y) layers were grown on (001) InP substrates by gas source molecular beam epitaxy. Low-temperature photoluminescence spectroscopy was applied to these heterostructures and revealed spatially indirect band-to-band recombination of electrons localized in the InP with holes in the (GaxIn1-x)(PySb1-y). In addition, samples with layer thicknesses larger than 100nm showed direct PL across the band gap of (GaxIn1-x)(PySb1-y). Band-gap energies and band offset energies of (GaxIn1-x)(PySb1-y) relative to InP were derived from these PL data. A strong bowing parameter was observed.

Investigations of nuclear structure and nuclear reactions induced by complex projectiles

International Nuclear Information System (INIS)

Sarantites, D.G.

1993-01-01

This is a progress report on activities of the Washington University group in nuclear reaction studies for the period Sept 1, 1992 to Aug 31, 1993. This group has a research program which touches five areas of nuclear physics: nuclear structure studies at high spin; studies at the interface between structure and reactions; production and study of hot nuclei; reaction mechanism studies; development and use of novel techniques and instrumentation in the above areas of research. Specific activities of the group include in part: superdeformation in 82 Sr; structure of and identical bands in 182 Hg and 178 Pt; a highly deformed band in 136 Pm; particle decay of the 164 Yb compound nucleus; fusion reactions; proton evaporation; two-proton decay of 12 O; modeling and theoretical studies; excited 16 O disassembly into four alpha particles; 209 Bi + 136 Xe collisions at 28.2 MeV/amu; and development work on 4π solid angle gamma detectors, and x-ray detectors

Evolutionary Steps in the Emergence of Life Deduced from the Bottom-Up Approach and GADV Hypothesis (Top-Down Approach).

Science.gov (United States)

Ikehara, Kenji

2016-01-26

It is no doubt quite difficult to solve the riddle of the origin of life. So, firstly, I would like to point out the kinds of obstacles there are in solving this riddle and how we should tackle these difficult problems, reviewing the studies that have been conducted so far. After that, I will propose that the consecutive evolutionary steps in a timeline can be rationally deduced by using a common event as a juncture, which is obtained by two counter-directional approaches: one is the bottom-up approach through which many researchers have studied the origin of life, and the other is the top-down approach, through which I established the [GADV]-protein world hypothesis or GADV hypothesis on the origin of life starting from a study on the formation of entirely new genes in extant microorganisms. Last, I will describe the probable evolutionary process from the formation of Earth to the emergence of life, which was deduced by using a common event-the establishment of the first genetic code encoding [GADV]-amino acids-as a juncture for the results obtained from the two approaches.

Evolutionary Steps in the Emergence of Life Deduced from the Bottom-Up Approach and GADV Hypothesis (Top-Down Approach

Directory of Open Access Journals (Sweden)

Kenji Ikehara

2016-01-01

Full Text Available It is no doubt quite difficult to solve the riddle of the origin of life. So, firstly, I would like to point out the kinds of obstacles there are in solving this riddle and how we should tackle these difficult problems, reviewing the studies that have been conducted so far. After that, I will propose that the consecutive evolutionary steps in a timeline can be rationally deduced by using a common event as a juncture, which is obtained by two counter-directional approaches: one is the bottom-up approach through which many researchers have studied the origin of life, and the other is the top-down approach, through which I established the [GADV]-protein world hypothesis or GADV hypothesis on the origin of life starting from a study on the formation of entirely new genes in extant microorganisms. Last, I will describe the probable evolutionary process from the formation of Earth to the emergence of life, which was deduced by using a common event—the establishment of the first genetic code encoding [GADV]-amino acids—as a juncture for the results obtained from the two approaches.

Dual-band infrared camera

Science.gov (United States)

Vogel, H.; Schlemmer, H.

2005-10-01

Every year, numerous accidents happen on European roads due to bad visibility (fog, night, heavy rain). Similarly, the dramatic aviation accidents of year 2001 in Milan and Zurich have reminded us that aviation safety is equally affected by reduced visibility. A dual-band thermal imager was developed in order to raise human situation awareness under conditions of reduced visibility especially in the automotive and aeronautical context but also for all transportation or surveillance tasks. The chosen wavelength bands are the Short Wave Infrared SWIR and the Long Wave Infrared LWIR band which are less obscured by reduced visibility conditions than the visible band. Furthermore, our field tests clearly show that the two different spectral bands very often contain complementary information. Pyramidal fusion is used to integrate complementary and redundant features of the multi-spectral images into a fused image which can be displayed on a monitor to provide more and better information for the driver or pilot.

50 MW C-band pulse klystron; 50MW C band pulse klystron

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

C-band pulse klystron E3746 with an output of 50 MW class was developed jointly with the High-Energy Accelerator Research Organization in the Ministry of Education as the klystron for a linear accelerator. For a large-sized linear accelerator in the next generation, a klystron with higher operating frequency has been required to obtain a compact and efficient accelerator. In E3746, the problem of power resistance during high-frequency operation was solved by mounting a traveling-wave multi-cell output circuit. Moreover, stable operation in the pulse width of 2.5 {mu}s and the output of 54 MW was performed at the same operation efficiency (44%) as the conventional S-band tube by using the frequency (in a C-band frequency band) that is two times as high as the conventional general accelerator. (translated by NEDO)

Hazard banding in compliance with the new Globally Harmonised System (GHS) for use in control banding tools.

Science.gov (United States)

Arnone, Mario; Koppisch, Dorothea; Smola, Thomas; Gabriel, Stefan; Verbist, Koen; Visser, Remco

2015-10-01

Many control banding tools use hazard banding in risk assessments for the occupational handling of hazardous substances. The outcome of these assessments can be combined with advice for the required risk management measures (RMMs). The Globally Harmonised System of Classification and Labelling of Chemicals (GHS) has resulted in a change in the hazard communication elements, i.e. Hazard (H) statements instead of Risk-phrases. Hazard banding schemes that depend on the old form of safety information have to be adapted to the new rules. The purpose of this publication is to outline the rationales for the assignment of hazard bands to H statements under the GHS. Based on this, this publication proposes a hazard banding scheme that uses the information from the safety data sheets as the basis for assignment. The assignment of hazard bands tiered according to the severity of the underlying hazards supports the important principle of substitution. Additionally, the set of assignment rules permits an exposure-route-specific assignment of hazard bands, which is necessary for the proposed route-specific RMMs. Ideally, all control banding tools should apply the same assignment rules. This GHS-compliant hazard banding scheme can hopefully help to establish a unified hazard banding strategy in the various control banding tools. Copyright © 2015 Elsevier Inc. All rights reserved.

Band parameters of phosphorene

DEFF Research Database (Denmark)

Lew Yan Voon, L. C.; Wang, J.; Zhang, Y.

2015-01-01

Phosphorene is a two-dimensional nanomaterial with a direct band-gap at the Brillouin zone center. In this paper, we present a recently derived effective-mass theory of the band structure in the presence of strain and electric field, based upon group theory. Band parameters for this theory...... are computed using a first-principles theory based upon the generalized-gradient approximation to the density-functional theory. These parameters and Hamiltonian will be useful for modeling physical properties of phosphorene....

Computational Design of Flat-Band Material

Science.gov (United States)

Hase, I.; Yanagisawa, T.; Kawashima, K.

2018-02-01

Quantum mechanics states that hopping integral between local orbitals makes the energy band dispersive. However, in some special cases, there are bands with no dispersion due to quantum interference. These bands are called as flat band. Many models having flat band have been proposed, and many interesting physical properties are predicted. However, no real compound having flat band has been found yet despite the 25 years of vigorous researches. We have found that some pyrochlore oxides have quasi-flat band just below the Fermi level by first principles calculation. Moreover, their valence bands are well described by a tight-binding model of pyrochlore lattice with isotropic nearest neighbor hopping integral. This model belongs to a class of Mielke model, whose ground state is known to be ferromagnetic with appropriate carrier doping and on-site repulsive Coulomb interaction. We have also performed a spin-polarized band calculation for the hole-doped system from first principles and found that the ground state is ferromagnetic for some doping region. Interestingly, these compounds do not include magnetic element, such as transition metal and rare-earth elements.

Multi-band Modelling of Appearance

DEFF Research Database (Denmark)

Stegmann, Mikkel Bille; Larsen, Rasmus

2003-01-01

the appearance of both derived feature bands and an intensity band. As a special case of feature-band augmented appearance modelling we propose a dedicated representation with applications to face segmentation. The representation addresses a major problem within face recognition by lowering the sensitivity...

Multi-band Modelling of Appearance

DEFF Research Database (Denmark)

Stegmann, Mikkel Bille; Larsen, Rasmus

2002-01-01

the appearance of both derived feature bands and an intensity band. As a special case of feature-band augmented appearance modelling we propose a dedicated representation with applications to face segmentation. The representation addresses a major problem within face recognition by lowering the sensitivity...

Systematic study of β-band and correlation with g- band using power law and soft rotor formula

International Nuclear Information System (INIS)

Katoch, Vikas; Kaushik, Reetu; Sharma, S.; Gupta, J.B.

2014-01-01

The nuclear structure of even Z even N medium mass transitional nuclei consist of ground state band, K π =0 1 β-band, K π =2 1 γ- band and other higher bands. As we move away from closed shell, energy levels are low lying from spherical to deformed nuclei and energy deviated from ideal rotor behavior. The energy of these transitional nuclei in ground band can also be studied using Bohr Mottelson energy expression, Soft Rotor Formula (SRF), Power Law (PL) etc. Recently, Gupta et al. (2013) modified SRF for non zero band head K π =2 1 γ-band and reproduced the level energies. Here same formula applied for K π =0 1 β-band and the level energies are reproduced and compared with experimental energies. The power law is also used for recalculation of level energies and for useful comparison

Table of members of quasi-bands

International Nuclear Information System (INIS)

Sakai, Mitsuo.

1984-04-01

The probable members of the quasi-bands in even-even nuclei for Z between 6 and 100 are listed in this table. The terms quasi-bands have been introduced in the so-called spherical regions as the counter parts of the collective bands in the deformed regions. In the present compilation, the data for deformed nuclei are classified for convenience under the same titles, Quasi-Ground Band, Quasi-Beta Band and Quasi-Gamma Band, as are used for other nuclear regions. The present edition covers the literature through September, 1983. Fifteen newly discovered nuclides are included. The classification of energy level into quasi-bands is made on the basis of the systematic trend in the data over large groups of nuclei. (Kato, T.)

Relation between plasmons and the valence-band density-of-states in polymethylmethacrylate - influence of ion irradiation on damage selectivity

International Nuclear Information System (INIS)

Moliton, J.P.; Jussiaux, C.; Trigaud, T.; Lazzaroni, R.; Lhost, O.; Bredas, J.L.; Kihn, Y.; Sevely, J.

1996-01-01

A physical model is presented that aims at rationalizing the selectivity of bond breakage observed when polymethylmethacrylate is irradiated by ions in the 10-500 keV energy range. This model, previously proposed by Brandt and Ritchie, is based on electronic collective effects. The coupling between the pure plasma oscillation at omega(p) and the oscillation of free electrons at [omega(k0)(2)](1/2) makes the whole electronic population resonant at the frequency omega(rp) = (omega(p)(2) + [omega(k0)(2)])(1/2). By computing the valence-band density of states, we calculate [omega(k0)(2)] and then deduce the theoretical value of omega(rp). On the other hand, we provide an experimental measurement of omega(rp) and study its dependence on ion fluence by electron-energy-loss spectroscopy. The validity of the model of Brandt and Ritchie is then discussed in the light of both theoretical and experimental data. (author)

Band parameters of phosphorene

International Nuclear Information System (INIS)

Lew Yan Voon, L C; Wang, J; Zhang, Y; Willatzen, M

2015-01-01

Phosphorene is a two-dimensional nanomaterial with a direct band-gap at the Brillouin zone center. In this paper, we present a recently derived effective-mass theory of the band structure in the presence of strain and electric field, based upon group theory. Band parameters for this theory are computed using a first-principles theory based upon the generalized-gradient approximation to the density-functional theory. These parameters and Hamiltonian will be useful for modeling physical properties of phosphorene. (paper)

Amniotic constriction bands

Science.gov (United States)

... Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Amniotic band sequence URL of this page: //medlineplus.gov/ency/ ... birth. The baby should be delivered in a medical center that has specialists experienced in caring for babies ... or partial loss of function of a body part. Congenital bands affecting large parts of the body cause the ...

Fracture-mechanics data deduced from thermal-shock and related experiments with LWR pressure-vessel material

International Nuclear Information System (INIS)

Cheverton, R.D.; Canonico, D.A.; Iskander, S.K.; Bolt, S.E.; Holz, P.P.; Nanstad, R.K.; Stelzman, W.J.

1982-01-01

Pressurized water reactors (PWRs) are susceptible to certain types of hypothetical accidents that can subject the reactor pressure vessel to severe thermal shock, that is, a rapid cooling of the inner surface of the vessel wall. The thermal-shock loading, coupled with the radiation-induced reduction in the material fracture toughness, introduces the possibility of propagation of preexistent flaws and what at one time were regarded as somewhat unique fracture-oriented conditions. Several postulated reactor accidents have been analyzed to discover flaw behavior trends; seven intermediate-scale thermal-shock experiments with steel cylinders have been conducted; and corresponding materials characterization studies have been performed. Flaw behavior trends and related fracture-mechanics data deduced from these studies are discussed

Hetero-gate-dielectric double gate junctionless transistor (HGJLT) with reduced band-to-band tunnelling effects in subthreshold regime

International Nuclear Information System (INIS)

Ghosh, Bahniman; Mondal, Partha; Akram, M. W.; Bal, Punyasloka; Salimath, Akshay Kumar

2014-01-01

We propose a hetero-gate-dielectric double gate junctionless transistor (HGJLT), taking high-k gate insulator at source side and low-k gate insulator at drain side, which reduces the effects of band-to-band tunnelling (BTBT) in the sub-threshold region. A junctionless transistor (JLT) is turned off by the depletion of carriers in the highly doped thin channel (device layer) which results in a significant band overlap between the valence band of the channel region and the conduction band of the drain region, due to off-state drain bias, that triggers electrons to tunnel from the valence band of the channel region to the conduction band of the drain region leaving behind holes in the channel. These effects of band-to-band tunnelling increase the sub-threshold leakage current, and the accumulation of holes in the channel forms a parasitic bipolar junction transistor (n–p–n BJT for channel JLT) in the lateral direction by the source (emitter), channel (base) and drain (collector) regions in JLT structure in off-state. The proposed HGJLT reduces the subthreshold leakage current and suppresses the parasitic BJT action in off-state by reducing the band-to-band tunnelling probability. (semiconductor devices)

47 CFR 90.531 - Band plan.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Band plan. 90.531 Section 90.531...-805 MHz Bands § 90.531 Band plan. This section sets forth the band plan for the 763-775 MHz and 793... and portables subject to Commission-approved regional planning committee regional plans. Transmitter...

Measurement of core level and band offsets at the interface of ITO/Hg{sub 3}In{sub 2}Te{sub 6}(1 1 0) heterojunction by synchrotron radiation photoelectron spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Li, Yapeng [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Fu, Li, E-mail: fuli@nwpu.edu.cn [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Sun, Jie [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Ibrahim, Kurash; Wang, Jia-ou [Laboratory of Synchrotron Radiation, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039 (China)

2016-02-15

Highlights: • The valence band maximum of ITO film and MIT were measured to be 1.6 eV and 0.6 eV, respectively. • The concentration of In element presented a trend of increasing first and then decreasing from MIT to ITO. • The valence band offsets of the ITO/MIT(1 1 0) heterojunction was confirmed to be a type-II band alignment phenomenon. - Abstract: The Indium Tin Oxide (ITO) film was deposited on the surface of Hg{sub 3}In{sub 2}Te{sub 6} (short for MIT) (1 1 0) for the fabrication of ITO/MIT(1 1 0) heterojunction by using the pulsed laser deposition method. In situ X-ray photoelectron spectroscopy was utilized to examine the band offsets and core level of ITO/MIT(1 1 0) heterojunctions. The result showed that the valence band maximum of ITO films and MIT(1 1 0) were 1.6 eV and 0.6 eV, respectively. Meanwhile, it was found that the binding energy of Te 3d, Sn 3d and Hg 4f remained unchanged during the ITO deposition process. However, the binding energy of O 1s and In 3d{sub 5/2} increased about 0.3 eV and 0.2 eV, respectively, with the thickness increasing of ITO film from 3.5 nm to 5 nm. This may due to the elements diffusion at the interface region during the film growing process. According to the core level spectrum, it can be speculated that no significant chemical reaction occurred at the interface of ITO/MIT(1 1 0). In addition, the valence band offset of the ITO/MIT(1 1 0) heterojunction can be calculated to be −1 ± 0.15 eV by the means of the photoelectron spectroscopy methods. The conduction band offset is deduced to be −3.96 ± 0.15 eV from the known valence band offset value, indicating that the band offsets of ITO/MIT(1 1 0) heterojunction is a type-II band alignment.

A Hypothesis: Life Initiated from Two Genes, as Deduced from the RNA World Hypothesis and the Characteristics of Life-Like Systems

Directory of Open Access Journals (Sweden)

Kunio Kawamura

2016-08-01

Full Text Available RNA played a central role in the emergence of the first life-like system on primitive Earth since RNA molecules contain both genetic information and catalytic activity. However, there are several drawbacks regarding the RNA world hypothesis. Here, I briefly discuss the feasibility of the RNA world hypothesis to deduce the RNA functions that are essential for forming a life-like system. At the same time, I have conducted a conceptual analysis of the characteristics of biosystems as a useful approach to deduce a realistic life-like system in relation to the definition of life. For instance, an RNA-based life-like system should possess enough stability to resist environmental perturbations, by developing a cell-like compartment, for instance. Here, a conceptual viewpoint is summarized to provide a realistic life-like system that is compatible with the primitive Earth environment and the capabilities of RNA molecules. According to the empirical and conceptual analysis, I propose the hypothesis that the first life-like system could have initiated from only two genes.

Two-band superconductor magnesium diboride

International Nuclear Information System (INIS)

Xi, X X

2008-01-01

This review focuses on the most important features of the 40 K superconductor MgB 2 -the weakly interacting multiple bands (the σ and π bands) and the distinct multiple superconducting energy gaps (the σ and π gaps). Even though the pairing mechanism of superconductor MgB 2 is the conventional electron-phonon coupling, the prominent influence of the two bands and two gaps on its properties sets it apart from other superconductors. It leads to markedly different behaviors in upper critical field, vortex structure, magnetoresistance and many other superconducting and normal-state properties in MgB 2 from single-band superconductors. Further, it gives rise to new physics that does not exist in single-band superconductors, such as the internal Josephson effects between the two order parameters. These unique phenomena depend sensitively on scattering inside and between the two bands, and the intraband and interband scattering can be modified by chemical substitution and irradiation. MgB 2 has brought unprecedented attention to two-band superconductivity, which has been found to exist in other old and new superconductors. The legacy of MgB 2 will be long lasting because of this, as well as the lessons it teaches in terms of the search for new phonon-mediated higher T c superconductors

Comparison of band-to-band tunneling models in Si and Si—Ge junctions

International Nuclear Information System (INIS)

Jiao Yipeng; Wang Taihuan; Wei Kangliang; Du Gang; Liu Xiaoyan

2013-01-01

We compared several different band-to-band tunneling (BTBT) models with both Sentaurus and the two-dimensional full-band Monte Carlo simulator in Si homo-junctions and Si—Ge hetero-junctions. It was shown that in Si homo-junctions, different models could achieve similar results. However, in the Si—Ge hetero-junctions, there were significant differences among these models at high reverse biases (over 2 V). Compared to the nonlocal model, the local models in Sentaurus underrated the BTBT rate distinctly, and the Monte Carlo method was shown to give a better approximation. Additionally, it was found that in the Si region near the interface of the Si—Ge hetero-junctions, the direct tunneling rates increased largely due to the interaction of the band structures of Si and Ge. (semiconductor physics)

Deep-Space Ka-Band Flight Experience

Science.gov (United States)

Morabito, D. D.

2017-11-01

Lower frequency bands have become more congested in allocated bandwidth as there is increased competition between flight projects and other entities. Going to higher frequency bands offers significantly more bandwidth, allowing for the use of much higher data rates. However, Ka-band is more susceptible to weather effects than lower frequency bands currently used for most standard downlink telemetry operations. Future or prospective flight projects considering deep-space Ka-band (32-GHz) telemetry data links have expressed an interest in understanding past flight experience with received Ka-band downlink performance. Especially important to these flight projects is gaining a better understanding of weather effects from the experience of current or past missions that operated Ka-band radio systems. We will discuss the historical flight experience of several Ka-band missions starting from Mars Observer in 1993 up to present-day deep-space missions such as Kepler. The study of historical Ka-band flight experience allows one to recommend margin policy for future missions. Of particular interest, we will review previously reported-on flight experience with the Cassini spacecraft Ka-band radio system that has been used for radio science investigations as well as engineering studies from 2004 to 2015, when Cassini was in orbit around the planet Saturn. In this article, we will focus primarily on the Kepler spacecraft Ka-band link, which has been used for operational telemetry downlink from an Earth trailing orbit where the spacecraft resides. We analyzed the received Ka-band signal level data in order to characterize link performance over a wide range of weather conditions and as a function of elevation angle. Based on this analysis of Kepler and Cassini flight data, we found that a 4-dB margin with respect to adverse conditions ensures that we achieve at least a 95 percent data return.

Elastic band prediction equations for combined free-weight and elastic band bench presses and squats.

Science.gov (United States)

Shoepe, Todd C; Ramirez, David A; Almstedt, Hawley C

2010-01-01

Elastic bands added to traditional free-weight techniques have become a part of suggested training routines in recent years. Because of the variable loading patterns of elastic bands (i.e., greater stretch produces greater resistance), it is necessary to quantify the exact loading patterns of bands to identify the volume and intensity of training. The purpose of this study was to determine the length vs. tension properties of multiple sizes of a set of commonly used elastic bands to quantify the resistance that would be applied to free-weight plus elastic bench presses (BP) and squats (SQ). Five elastic bands of varying thickness were affixed to an overhead support beam. Dumbbells of varying weights were progressively added to the free end while the linear deformation was recorded with each subsequent weight increment. The resistance was plotted as a factor of linear deformation, and best-fit nonlinear logarithmic regression equations were then matched to the data. For both the BP and SQ loading conditions and all band thicknesses tested, R values were greater than 0.9623. These data suggest that differences in load exist as a result of the thickness of the elastic band, attachment technique, and type of exercise being performed. Facilities should adopt their own form of loading quantification to match their unique set of circumstances when acquiring, researching, and implementing elastic band and free-weight exercises into the training programs.

Solid State KA-Band, Solid State W-Band and TWT Amplifiers, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Phase I of the proposal describes plans to develop a state of the art transmitter for the W-Band and KA -Band Cloud Radar system. Our focus will be concentrated in...

Radial plasma drifts deduced from VLF whistler mode signals - A modelling study

Science.gov (United States)

Poulter, E. M.; Andrews, M. K.; Bailey, G. J.; Moffett, R. J.

1984-05-01

VLF whistler mode signals have previously been used to infer radial plasma drifts in the equatorial plane of the plasmasphere and the field-aligned ionosphere-protonosphere coupling fluxes. Physical models of the plasmasphere consisting of O(+) adn H(+) ions along dipole magnetic field lines, and including radial E x B drifts, are applied to a mid-latitude flux tube appropriate to whistler mode signals received at Wellington, New Zealand, from the fixed frequency VLF transmitter NLK (18.6 kHz) in Seattle, U.S.A. These models are first shown to provide a good representation of the recorded Doppler shift and group delay data. They are then used to simulate the process of deducing the drifts and fluxes from the recorded data. Provided the initial whistler mode duct latitude and the ionospheric contributions are known, the drifts at the equatorial plane can be estimated to about + or - 20 m/s (approximately 10-15 percent), and the two hemisphere ionosphere-protonosphere coupling fluxes to about + or - 10 to the 12th/sq m-sec (approximately 40 percent).

The dynamics of a shear band

Science.gov (United States)

Giarola, Diana; Capuani, Domenico; Bigoni, Davide

2018-03-01

A shear band of finite length, formed inside a ductile material at a certain stage of a continued homogeneous strain, provides a dynamic perturbation to an incident wave field, which strongly influences the dynamics of the material and affects its path to failure. The investigation of this perturbation is presented for a ductile metal, with reference to the incremental mechanics of a material obeying the J2-deformation theory of plasticity (a special form of prestressed, elastic, anisotropic, and incompressible solid). The treatment originates from the derivation of integral representations relating the incremental mechanical fields at every point of the medium to the incremental displacement jump across the shear band faces, generated by an impinging wave. The boundary integral equations (under the plane strain assumption) are numerically approached through a collocation technique, which keeps into account the singularity at the shear band tips and permits the analysis of an incident wave impinging a shear band. It is shown that the presence of the shear band induces a resonance, visible in the incremental displacement field and in the stress intensity factor at the shear band tips, which promotes shear band growth. Moreover, the waves scattered by the shear band are shown to generate a fine texture of vibrations, parallel to the shear band line and propagating at a long distance from it, but leaving a sort of conical shadow zone, which emanates from the tips of the shear band.

Retrospective biodosimetry with small tooth enamel samples using K-Band and X-Band

International Nuclear Information System (INIS)

Gomez, Jorge A.; Kinoshita, Angela; Leonor, Sergio J.; Belmonte, Gustavo C.; Baffa, Oswaldo

2011-01-01

In an attempt to make the in vitro electron spin resonance (ESR) retrospective dosimetry of the tooth enamel a lesser invasive method, experiments using X-Band and K-Band were performed, aiming to determine conditions that could be used in cases of accidental exposures. First, a small prism from the enamel was removed and ground with an agate mortar and pestle until particles reach a diameter of approximately less than 0.5 mm. This enamel extraction process resulted in lower signal artifact compared with the direct enamel extraction performed with a diamond burr abrasion. The manual grinding of the enamel does not lead to any induced ESR signal artifact, whereas the use of a diamond burr at low speed produces a signal artifact equivalent to the dosimetric signal induced by a dose of 500 mGy of gamma irradiation. A mass of 25 mg of enamel was removed from a sound molar tooth previously irradiated in vitro with a dose of 100 mGy. This amount of enamel was enough to detect the dosimetric signal in a standard X-Band spectrometer. However using a K-Band spectrometer, samples mass between 5 and 10 mg were sufficient to obtain the same sensitivity. An overall evaluation of the uncertainties involved in the process in this and other dosimetric assessments performed at our laboratory indicates that it is possible at K-Band to estimate a 100 mGy dose with 25% accuracy. In addition, the use of K-Band also presented higher sensitivity and allowed the use of smaller sample mass in comparison with X-Band. Finally, the restoration process performed on a tooth after extraction of the 25 mg of enamel is described. This was conducted by dental treatment using photopolymerizable resin which enabled complete recovery of the tooth from the functional and aesthetic viewpoint showing that this procedure can be minimally invasive.

Retrospective biodosimetry with small tooth enamel samples using K-Band and X-Band

Energy Technology Data Exchange (ETDEWEB)

Gomez, Jorge A. [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Kinoshita, Angela [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Universidade Sagrado Coracao - USC, 17011-160 Bauru, Sao Paulo (Brazil); Leonor, Sergio J. [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Belmonte, Gustavo C. [Universidade Sagrado Coracao - USC, 17011-160 Bauru, Sao Paulo (Brazil); Baffa, Oswaldo, E-mail: baffa@usp.br [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, Sao Paulo (Brazil)

2011-09-15

In an attempt to make the in vitro electron spin resonance (ESR) retrospective dosimetry of the tooth enamel a lesser invasive method, experiments using X-Band and K-Band were performed, aiming to determine conditions that could be used in cases of accidental exposures. First, a small prism from the enamel was removed and ground with an agate mortar and pestle until particles reach a diameter of approximately less than 0.5 mm. This enamel extraction process resulted in lower signal artifact compared with the direct enamel extraction performed with a diamond burr abrasion. The manual grinding of the enamel does not lead to any induced ESR signal artifact, whereas the use of a diamond burr at low speed produces a signal artifact equivalent to the dosimetric signal induced by a dose of 500 mGy of gamma irradiation. A mass of 25 mg of enamel was removed from a sound molar tooth previously irradiated in vitro with a dose of 100 mGy. This amount of enamel was enough to detect the dosimetric signal in a standard X-Band spectrometer. However using a K-Band spectrometer, samples mass between 5 and 10 mg were sufficient to obtain the same sensitivity. An overall evaluation of the uncertainties involved in the process in this and other dosimetric assessments performed at our laboratory indicates that it is possible at K-Band to estimate a 100 mGy dose with 25% accuracy. In addition, the use of K-Band also presented higher sensitivity and allowed the use of smaller sample mass in comparison with X-Band. Finally, the restoration process performed on a tooth after extraction of the 25 mg of enamel is described. This was conducted by dental treatment using photopolymerizable resin which enabled complete recovery of the tooth from the functional and aesthetic viewpoint showing that this procedure can be minimally invasive.

Dust bands in the asteroid belt

International Nuclear Information System (INIS)

Sykes, M.V.; Greenberg, R.; Dermott, S.F.; Nicholson, P.D.; Burns, J.A.

1989-01-01

This paper describes the original IRAS observations leading to the discovery of the three dust bands in the asteroid belt and the analysis of data. Special attention is given to an analytical model of the dust band torus and to theories concerning the origin of the dust bands, with special attention given to the collisional equilibrium (asteroid family), the nonequilibrium (random collision), and the comet hypotheses of dust-band origin. It is noted that neither the equilibrium nor nonequilibrium models, as currently formulated, present a complete picture of the IRAS dust-band observations. 32 refs

Thematic mapper studies band correlation analysis

Science.gov (United States)

Ungar, S. G.; Kiang, R.

1976-01-01

Spectral data representative of thematic mapper candidate bands 1 and 3 to 7 were obtained by selecting appropriate combinations of bands from the JSC 24 channel multispectral scanner. Of all the bands assigned, only candidate bands 4 (.74 mu to .80 mu) and 5 (.80 mu to .91 mu) showed consistently high intercorrelation from region to region and time to time. This extremely high correlation persisted when looking at the composite data set in a multitemporal, multilocation domain. The GISS investigations lend positive confirmation to the hypothesis, that TM bands 4 and 5 are redundant.

Modeling direct band-to-band tunneling: From bulk to quantum-confined semiconductor devices

Science.gov (United States)

Carrillo-Nuñez, H.; Ziegler, A.; Luisier, M.; Schenk, A.

2015-06-01

A rigorous framework to study direct band-to-band tunneling (BTBT) in homo- and hetero-junction semiconductor nanodevices is introduced. An interaction Hamiltonian coupling conduction and valence bands (CVBs) is derived using a multiband envelope method. A general form of the BTBT probability is then obtained from the linear response to the "CVBs interaction" that drives the system out of equilibrium. Simple expressions in terms of the one-electron spectral function are developed to compute the BTBT current in two- and three-dimensional semiconductor structures. Additionally, a two-band envelope equation based on the Flietner model of imaginary dispersion is proposed for the same purpose. In order to characterize their accuracy and differences, both approaches are compared with full-band, atomistic quantum transport simulations of Ge, InAs, and InAs-Si Esaki diodes. As another numerical application, the BTBT current in InAs-Si nanowire tunnel field-effect transistors is computed. It is found that both approaches agree with high accuracy. The first one is considerably easier to conceive and could be implemented straightforwardly in existing quantum transport tools based on the effective mass approximation to account for BTBT in nanodevices.

Modeling direct band-to-band tunneling: From bulk to quantum-confined semiconductor devices

International Nuclear Information System (INIS)

Carrillo-Nuñez, H.; Ziegler, A.; Luisier, M.; Schenk, A.

2015-01-01

A rigorous framework to study direct band-to-band tunneling (BTBT) in homo- and hetero-junction semiconductor nanodevices is introduced. An interaction Hamiltonian coupling conduction and valence bands (CVBs) is derived using a multiband envelope method. A general form of the BTBT probability is then obtained from the linear response to the “CVBs interaction” that drives the system out of equilibrium. Simple expressions in terms of the one-electron spectral function are developed to compute the BTBT current in two- and three-dimensional semiconductor structures. Additionally, a two-band envelope equation based on the Flietner model of imaginary dispersion is proposed for the same purpose. In order to characterize their accuracy and differences, both approaches are compared with full-band, atomistic quantum transport simulations of Ge, InAs, and InAs-Si Esaki diodes. As another numerical application, the BTBT current in InAs-Si nanowire tunnel field-effect transistors is computed. It is found that both approaches agree with high accuracy. The first one is considerably easier to conceive and could be implemented straightforwardly in existing quantum transport tools based on the effective mass approximation to account for BTBT in nanodevices

Modeling direct band-to-band tunneling: From bulk to quantum-confined semiconductor devices

Energy Technology Data Exchange (ETDEWEB)

Carrillo-Nuñez, H.; Ziegler, A.; Luisier, M.; Schenk, A. [Integrated Systems Laboratory ETH Zürich, Gloriastrasse 35, 8092 Zürich (Switzerland)

2015-06-21

A rigorous framework to study direct band-to-band tunneling (BTBT) in homo- and hetero-junction semiconductor nanodevices is introduced. An interaction Hamiltonian coupling conduction and valence bands (CVBs) is derived using a multiband envelope method. A general form of the BTBT probability is then obtained from the linear response to the “CVBs interaction” that drives the system out of equilibrium. Simple expressions in terms of the one-electron spectral function are developed to compute the BTBT current in two- and three-dimensional semiconductor structures. Additionally, a two-band envelope equation based on the Flietner model of imaginary dispersion is proposed for the same purpose. In order to characterize their accuracy and differences, both approaches are compared with full-band, atomistic quantum transport simulations of Ge, InAs, and InAs-Si Esaki diodes. As another numerical application, the BTBT current in InAs-Si nanowire tunnel field-effect transistors is computed. It is found that both approaches agree with high accuracy. The first one is considerably easier to conceive and could be implemented straightforwardly in existing quantum transport tools based on the effective mass approximation to account for BTBT in nanodevices.

Band-to-Band Misregistration of the Images of MODIS Onboard Calibrators and Its Impact on Calibration

Science.gov (United States)

Wang, Zhipeng; Xiong, Xiaoxiong

2017-01-01

The Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard Terra and Aqua satellites are radiometrically calibrated on-orbit with a set of onboard calibrators (OBCs), including a solar diffuser, a blackbody, and a space view port through which the detectors can view the dark space. As a whisk-broom scanning spectroradiometer, thirty-six MODIS spectral bands are assembled in the along-scan direction on four focal plane assemblies (FPAs). These bands capture images of the same target sequentially with the motion of a scan mirror. Then the images are coregistered onboard by delaying the appropriate band-dependent amount of time, depending on the band locations on the FPA. While this coregistration mechanismis functioning well for the far-field remote targets such as earth view scenes or the moon, noticeable band-to-band misregistration in the along-scan direction has been observed for near field targets, particularly in OBCs. In this paper, the misregistration phenomenon is presented and analyzed. It is concluded that the root cause of the misregistration is that the rotating element of the instrument, the scan mirror, is displaced from the focus of the telescope primary mirror. The amount of the misregistrationis proportional to the band location on the FPA and is inversely proportional to the distance between the target and the scan mirror. The impact of this misregistration on the calibration of MODIS bands is discussed. In particular, the calculation of the detector gain coefficient m1of bands 8-16 (412 nm 870 nm) is improved by up to 1.5% for Aqua MODIS.

Infrared diffuse interstellar bands

Science.gov (United States)

Galazutdinov, G. A.; Lee, Jae-Joon; Han, Inwoo; Lee, Byeong-Cheol; Valyavin, G.; Krełowski, J.

2017-05-01

We present high-resolution (R ˜ 45 000) profiles of 14 diffuse interstellar bands in the ˜1.45 to ˜2.45 μm range based on spectra obtained with the Immersion Grating INfrared Spectrograph at the McDonald Observatory. The revised list of diffuse bands with accurately estimated rest wavelengths includes six new features. The diffuse band at 15 268.2 Å demonstrates a very symmetric profile shape and thus can serve as a reference for finding the 'interstellar correction' to the rest wavelength frame in the H range, which suffers from a lack of known atomic/molecular lines.

Analysis of optical band-gap shift in impurity doped ZnO thin films by using nonparabolic conduction band parameters

International Nuclear Information System (INIS)

Kim, Won Mok; Kim, Jin Soo; Jeong, Jeung-hyun; Park, Jong-Keuk; Baik, Young-Jun; Seong, Tae-Yeon

2013-01-01

Polycrystalline ZnO thin films both undoped and doped with various types of impurities, which covered the wide carrier concentration range of 10 16 –10 21 cm −3 , were prepared by magnetron sputtering, and their optical-band gaps were investigated. The experimentally measured optical band-gap shifts were analyzed by taking into account the carrier density dependent effective mass determined by the first-order nonparabolicity approximation. It was shown that the measured shifts in optical band-gaps in ZnO films doped with cationic dopants, which mainly perturb the conduction band, could be well represented by theoretical estimation in which the band-gap widening due to the band-filling effect and the band-gap renormalization due to the many-body effect derived for a weakly interacting electron-gas model were combined and the carrier density dependent effective mass was incorporated. - Highlights: ► Optical band-gaps of polycrystalline ZnO thin films were analyzed. ► Experimental carrier concentration range covered from 10 16 to 10 21 cm −3 . ► Nonparabolic conduction band parameters were used in theoretical analysis. ► The band-filling and the band-gap renormalization effects were considered. ► The measured optical band-gap shifts corresponded well with the calculated ones

Modelling band-to-band tunneling current in InP-based heterostructure photonic devices

NARCIS (Netherlands)

van Engelen, J.P.; Shen, L.; van der Tol, J.J.G.M.; Smit, M.K.; Kockaert, P.; Emplit, P.; Gorza, S.-P.; Massar, S.

2015-01-01

Some semiconductor photonic devices show large discontinuities in the band structure. Short tunnel paths caused by this band structure may lead to an excessive tunneling current, especially in highly doped layers. Modelling of this tunnelling current is therefore important when designing photonic

Change in optimum genetic algorithm solution with changing band discontinuities and band widths of electrically conducting copolymers

Science.gov (United States)

Kaur, Avneet; Bakhshi, A. K.

2010-04-01

The interest in copolymers stems from the fact that they present interesting electronic and optical properties leading to a variety of technological applications. In order to get a suitable copolymer for a specific application, genetic algorithm (GA) along with negative factor counting (NFC) method has recently been used. In this paper, we study the effect of change in the ratio of conduction band discontinuity to valence band discontinuity (Δ Ec/Δ Ev) on the optimum solution obtained from GA for model binary copolymers. The effect of varying bandwidths on the optimum GA solution is also investigated. The obtained results show that the optimum solution changes with varying parameters like band discontinuity and band width of constituent homopolymers. As the ratio Δ Ec/Δ Ev increases, band gap of optimum solution decreases. With increasing band widths of constituent homopolymers, the optimum solution tends to be dependent on the component with higher band gap.

Band connectivity for topological quantum chemistry: Band structures as a graph theory problem

Science.gov (United States)

Bradlyn, Barry; Elcoro, L.; Vergniory, M. G.; Cano, Jennifer; Wang, Zhijun; Felser, C.; Aroyo, M. I.; Bernevig, B. Andrei

2018-01-01

The conventional theory of solids is well suited to describing band structures locally near isolated points in momentum space, but struggles to capture the full, global picture necessary for understanding topological phenomena. In part of a recent paper [B. Bradlyn et al., Nature (London) 547, 298 (2017), 10.1038/nature23268], we have introduced the way to overcome this difficulty by formulating the problem of sewing together many disconnected local k .p band structures across the Brillouin zone in terms of graph theory. In this paper, we give the details of our full theoretical construction. We show that crystal symmetries strongly constrain the allowed connectivities of energy bands, and we employ graph theoretic techniques such as graph connectivity to enumerate all the solutions to these constraints. The tools of graph theory allow us to identify disconnected groups of bands in these solutions, and so identify topologically distinct insulating phases.

Vortex magnetic structure in circularly magnetized microwires as deduced from magneto-optical Kerr measurements

KAUST Repository

Ivanov, Yurii P.

2014-02-14

The magneto-optic Kerr effect has been employed to determine the magnetization process and estimate the domain structure of microwires with circular magnetic anisotropy. The diameter of microwires was 8 μm, and pieces 2 cm long were selected for measurements. The analysis of the local surface longitudinal and transverse hysteresis loops has allowed us to deduce a vortex magnetic structure with axial core and circular external shell. Moreover, a bamboo-like surface domain structure is confirmed with wave length of around 10 to 15 μm and alternating chirality in adjacent circular domains. The width of the domain wall is estimated to be less than 3 μm. Finally, closure domain structures with significant helical magnetization component are observed extending up to around 1000 μm from the end of the microwire.

Vortex magnetic structure in circularly magnetized microwires as deduced from magneto-optical Kerr measurements

KAUST Repository

Ivanov, Yurii P.; del Real, R. P.; Chubykalo-Fesenko, O.; Vá zquez, M.

2014-01-01

The magneto-optic Kerr effect has been employed to determine the magnetization process and estimate the domain structure of microwires with circular magnetic anisotropy. The diameter of microwires was 8 μm, and pieces 2 cm long were selected for measurements. The analysis of the local surface longitudinal and transverse hysteresis loops has allowed us to deduce a vortex magnetic structure with axial core and circular external shell. Moreover, a bamboo-like surface domain structure is confirmed with wave length of around 10 to 15 μm and alternating chirality in adjacent circular domains. The width of the domain wall is estimated to be less than 3 μm. Finally, closure domain structures with significant helical magnetization component are observed extending up to around 1000 μm from the end of the microwire.

Systematics of criticality data of special actinide nuclides deduced through the Trombay criticality formula

International Nuclear Information System (INIS)

Srinivasan, M.; SubbaRao, K.; Garg, S.B.; Acharya, G.V.

1989-01-01

The authors describe a number of interesting systematics and correlations deduced by analyzing the criticality data of special actinide nuclides using concepts embodied in the Trombay critically formula (TCF). The κ ∞ of fast metal actinide nuclides gives a remarkable linear correlation with the fissility parameter Z 2 /A. The neutron leakage probability of all fast metal cores characterized using a constant parameter σ std enables computation of the critical mass value of any unknown fissile nuclide knowing only its Z 2 /A value. Since the neutron leakage probability from dilute fissile solutions is primarily governed by the scattering/slowing down properties of the hydrogen present in water, critical masses and subcritical limits can be predicted for any water-reflected system at any specified hydrogen-to-actinide atomic ratio knowing only the κ ∞ value of the given fissile solution

Wide Band to ''Double Band'' upgrade

International Nuclear Information System (INIS)

Kasper, P.; Currier, R.; Garbincius, P.; Butler, J.

1988-06-01

The Wide Band beam currently uses electrons obtained from secondary photon conversions to produce the photon beam incident on the experimental targets. By transporting the positrons produced in these conversions as well as the electrons it is possible to almost double the number of photons delivered to the experiments per primary beam proton. 11 figs

Thermal evolution of the band edges of 6H-SiC: X-ray methods compared to the optical band gap

International Nuclear Information System (INIS)

Miedema, P.S.; Beye, M.; Könnecke, R.; Schiwietz, G.; Föhlisch, A.

2014-01-01

Highlights: • Conduction band minima (CBM) of 6H-SiC are estimated with Si 2p XAS. • Valence band maxima (VBM) of 6H-SiC are estimated with non-resonant Si 2p XES. • Temperature-dependent VBM and CBM of 6H-SiC show asymmetric band gap closing. • XAS, XES and RIXS band gap estimates are compared with the optical band gap. • XAS + XES versus optical band gap provides core-excitonic screening energies. - Abstract: The band gap of semiconductors like silicon and silicon carbide (SiC) is the key for their device properties. In this research, the band gap of 6H-SiC and its temperature dependence were analyzed with silicon 2p X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS) allowing for a separate analysis of the conduction-band minimum (CBM) and valence-band maximum (VBM) components of the band gap. The temperature-dependent asymmetric band gap shrinking of 6H-SiC was determined with a valence-band slope of +2.45 × 10 −4 eV/K and a conduction-band slope of −1.334 × 10 −4 eV/K. The apparent asymmetry, e.g., that two thirds of the band-gap shrinking with increasing temperature is due to the VBM evolution in 6H-SiC, is similar to the asymmetry obtained for pure silicon before. The overall band gap temperature-dependence determined with XAS and non-resonant XES is compared to temperature-dependent optical studies. The core-excitonic binding energy appearing in the Si 2p XAS is extracted as the main difference. In addition, the energy loss of the onset of the first band in RIXS yields to values similar to the optical band gap over the tested temperature range

UWB Filtering Power Divider with Two Narrow Notch-bands and Wide Stop-band

Science.gov (United States)

Wei, Feng; Wang, Xin-Yi; Zou, Xin Tong; Shi, Xiao Wei

2017-12-01

A compact filtering ultra-wideband (UWB) microstrip power divider (PD) with two sharply rejected notch-bands and wide stopband is analyzed and designed in this paper. The proposed UWB PD is based on a conventional Wilkinson power divider, while two stub loaded resonators (SLRs) are coupled into two symmetrical output ports to achieve a bandpass filtering response. The simplified composite right/left-handed (SCRLH) resonators are employed to generate the dual notched bands. Defected ground structure (DGS) is introduced to improve the passband performance. Good insertion/return losses, isolation and notch-band rejection are achieved as demonstrated in both simulation and experiment.

Clinical significance of determination of changes of serum SOD and T-cell subsets distribution type after leukocyte-deduced red blood cell transfusion in patients with lung cancer

International Nuclear Information System (INIS)

Yu Zhengqin; Li Keqin; Xiang Hengquan

2006-01-01

Objective: To investigate the changes of serum SOD contents and T-cell subsets distribution type after leukocyte-deduced red blood cell transfusion in patients with lung cancer. Methods: Serum SOD levels was measured with RIA and T-cell subsets distribution type was detected with monoclonal antibody technic both before and after leukocyte-deduced red blood cell transfusion in 32 patients with lung cancer and 35 normal controls. Results: Before treatment, the serum levels of SOD and T-cell CIM/ CD8 value were significantly lower in the patients than those in controls (P 0.05). Conclusion: Determination of serum SOD level and T-cell subsets distribution type is clinically useful in the management of patients with lung cancer. (authors)

F-region Pedersen conductivity deduced using the TIMED/GUVI limb retrievals

Directory of Open Access Journals (Sweden)

Y. Zhang

2006-07-01

Full Text Available As a proxy of the Rayleigh-Taylor instability growth rate for equatorial plasma bubbles, we investigate the flux-tube integrated F-region Pedersen conductivity (ΣPF using the electron density profiles (EDPs provided by the Global Ultraviolet Imager (GUVI on board the Thermosphere Ionosphere and Mesosphere Energetics and Dynamics (TIMED satellite. The investigation is conducted using the EDPs obtained in the Atlantic sector at 19:00-22:00 LT during 4–17 August and 6-16 December 2002. The seasonal difference of the strength and location of the equatorial ionization anomalies (EIAs induces a significant difference in the deduced ΣPF. Much stronger EIAs are created at higher altitudes and latitudes in December rather than in August. At 19:00–20:00 LT, the peak value of the ΣPF has 23 mhos at 1100 km apex height during 14–16 December and 18mhos at 600 km during 15–17 August. The ΣPF decreases as local time progresses. Therefore, ΣPF provides a preferred condition for the growth of bubbles to higher altitudes at 19:00-20:00 LT than at later hours, in December rather than in August in the Atlantic sector.

Band-type microelectrodes for amperometric immunoassays

Energy Technology Data Exchange (ETDEWEB)

Lee, Ga-Yeon; Chang, Young Wook; Ko, Hyuk [Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120-749 (Korea, Republic of); Kang, Min-Jung [Korea Institute of Science and Technology (KIST), Seoul (Korea, Republic of); Pyun, Jae-Chul, E-mail: jcpyun@yonsei.ac.kr [Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120-749 (Korea, Republic of)

2016-07-20

A band-type microelectrode was made using a parylene-N film as a passivation layer. A circular-type, mm-scale electrode with the same diameter as the band-type microelectrode was also made with an electrode area that was 5000 times larger than the band-type microelectrode. By comparing the amperometric signals of 3,5,3′,5′-tetramethylbenzidine (TMB) samples at different optical density (OD) values, the band-type microelectrode was determined to be 9 times more sensitive than the circular-type electrode. The properties of the circular-type and the band-type electrodes (e.g., the shape of their cyclic voltammograms, the type of diffusion layer used, and the diffusion layer thickness per unit electrode area) were characterized according to their electrode area using the COMSOL Multiphysics software. From these simulations, the band-type electrode was estimated to have the conventional microelectrode properties, even when the electrode area was 100 times larger than a conventional circular-type electrode. These results show that both the geometry and the area of an electrode can influence the properties of the electrode. Finally, amperometric analysis based on a band-type electrode was applied to commercial ELISA kits to analyze human hepatitis B surface antigen (hHBsAg) and human immunodeficiency virus (HIV) antibodies. - Highlights: • A band-type microelectrode was made using a parylene-N film as a passivation layer. • The band-type microelectrode was 14-times more sensitive than circular-type electrode. • The influence of geometry on microelectrode properties was simulated using COMSOL. • The band-type electrode was applied to ELISA kits for hHBsAg and hHIV-antibodies.

Convex Banding of the Covariance Matrix.

Science.gov (United States)

Bien, Jacob; Bunea, Florentina; Xiao, Luo

2016-01-01

We introduce a new sparse estimator of the covariance matrix for high-dimensional models in which the variables have a known ordering. Our estimator, which is the solution to a convex optimization problem, is equivalently expressed as an estimator which tapers the sample covariance matrix by a Toeplitz, sparsely-banded, data-adaptive matrix. As a result of this adaptivity, the convex banding estimator enjoys theoretical optimality properties not attained by previous banding or tapered estimators. In particular, our convex banding estimator is minimax rate adaptive in Frobenius and operator norms, up to log factors, over commonly-studied classes of covariance matrices, and over more general classes. Furthermore, it correctly recovers the bandwidth when the true covariance is exactly banded. Our convex formulation admits a simple and efficient algorithm. Empirical studies demonstrate its practical effectiveness and illustrate that our exactly-banded estimator works well even when the true covariance matrix is only close to a banded matrix, confirming our theoretical results. Our method compares favorably with all existing methods, in terms of accuracy and speed. We illustrate the practical merits of the convex banding estimator by showing that it can be used to improve the performance of discriminant analysis for classifying sound recordings.

Band-to-band transitions, selection rules, effective mass, and excitonic contributions in monoclinic β -Ga2O3

Science.gov (United States)

Mock, Alyssa; Korlacki, Rafał; Briley, Chad; Darakchieva, Vanya; Monemar, Bo; Kumagai, Yoshinao; Goto, Ken; Higashiwaki, Masataka; Schubert, Mathias

2017-12-01

We employ an eigenpolarization model including the description of direction dependent excitonic effects for rendering critical point structures within the dielectric function tensor of monoclinic β -Ga2O3 yielding a comprehensive analysis of generalized ellipsometry data obtained from 0.75-9 eV. The eigenpolarization model permits complete description of the dielectric response. We obtain, for single-electron and excitonic band-to-band transitions, anisotropic critical point model parameters including their polarization vectors within the monoclinic lattice. We compare our experimental analysis with results from density functional theory calculations performed using the Gaussian-attenuation-Perdew-Burke-Ernzerhof hybrid density functional. We present and discuss the order of the fundamental direct band-to-band transitions and their polarization selection rules, the electron and hole effective mass parameters for the three lowest band-to-band transitions, and their excitonic contributions. We find that the effective masses for holes are highly anisotropic and correlate with the selection rules for the fundamental band-to-band transitions. The observed transitions are polarized close to the direction of the lowest hole effective mass for the valence band participating in the transition.

Intruder bands in Z = 51 nuclei

International Nuclear Information System (INIS)

LaFosse, D.R.

1993-01-01

Recent investigations of h 11/2 proton intruder bands in odd 51 Sb nuclei are reported. In addition to experiments performed at SUNY Stony Brook and Chalk River, data from Early Implementation of GAMMASPHERE (analysis in progress) are presented. In particular, the nuclei 109 Sb and 111 Sb are discussed. Rotational bands based on the πh 11/2 orbital coupled to a 2p2h deformed state of the 50 Sn core have been observed. These bands have been observed to high spin, and in the case of 109 Sb to a rotational frequency of 1.4 MeV, the highest frequency observed in a heavy nucleus. The dynamic moments of inertia in these bands decrease slowly with frequency, suggesting a gradual band termination. The systematics of such bands in 109-119 Sb will be discussed

Band 3 in aging and neurological disease.

Science.gov (United States)

Kay, M M

1991-01-01

Senescent cell antigen appears on old cells and marks them for death by initiating the binding of IgG autoantibody and subsequent removal by phagocytes in mammals and other vertebrates. We have created a synthetic aging antigen that blocks binding of IgG to senescent cells in vitro. Synthetic senescent cell antigen might be effective in preventing cellular destruction in vivo in certain diseases, and can be used to manipulate cellular life span in situ. Senescent cell antigen is generated by the modification of an important structural and transport membrane molecule, protein band 3. Band 3 is present in cellular, nuclear, Golgi, and mitochondrial membranes as well as in cell membranes. Band 3 proteins in nucleated cells participate in cell surface patching and capping. Band 3 maintains acid-base balance by mediating the exchange of anions (e.g., chloride, bicarbonate), and is the binding site for glycolytic enzymes. It is responsible for CO2 exchange in all tissues and organs. Thus, it is the most heavily used anion transport system in the body. Band 3 is a major transmembrane structural protein which attaches the plasma membrane to the internal cell cytoskeleton by binding to band 2.1 (ankyrin). Oxidation generates senescent cell antigen in situ. Band 3 is present in the central nervous system, and differences have been described in band 3 between young and aging brain tissue. One autosomal recessive neurological disease, choreoacanthocytosis, is associated with band 3 abnormalities. The 150 residues of the carboxyl terminus segment of band 3 appear to be altered. In brains from Alzheimer's disease patients, antibodies to aged band 3 label the amyloid core of classical plaques and the microglial cells located in the middle of the plaque in tissue sections, and an abnormal band 3 in immunoblots. Band 3 protein(s) in mammalian brain performs the same functions as that of erythroid band 3. These functions is anion transport, ankyrin binding, and generation of

Energy correlations for mixed rotational bands

International Nuclear Information System (INIS)

Doessing, T.

1985-01-01

A schematic model for the mixing of rotational bands above the yrast line in well deformed nuclei is considered. Many-particle configurations of a rotating mean field form basis bands, and these are subsequently mixed due to a two body residual interaction. The energy interval over which a basis band is spread out increases with increasing excitation energy above the yrast line. Conversely, the B(E2) matrix element for rotational decay out of one of the mixed band states is spread over an interval which is predicted to become more narrow with increasing excitation energy. Finally, the implication of band mixing for γ-ray energy correlations is briefly discussed. (orig.)

Changes in electron precipitation inferred from spectra deduced from D region electron densities during a post--magnetic storm effect

International Nuclear Information System (INIS)

Montbriand, L.E.; Belrose, J.S.

1976-01-01

The occurrence of enhanced ionization after geomagnetic storms, commonly referred to as storm aftereffect, is investigated on the hypothesis that the enhancement is due to a 'drizzle' of energetic electrons from the radiation belts. The study utilized electron density-height profiles obtained from the partial reflection experiment at Ottawa and available information on the height profile of the steady state loss coefficient for energetic electron events in combination with the ion pair production treatments of Ress (1963) and Berger et al. (1974) to deduce two-component differential energy spectra of the electron drizzle. The period studied, December 13--20, 1970, was unique for examining poststorm effects in that the geomagnetic storm on December 14--15 was intense and brief, and it was preceded and followed by periods of geomagnetic calm. The results indicate that the drizzle deduced was minimal before the storm and on the storm day and maximized 2--3 days after the peak of the storm at a time when geomagnetic activity had returned to calm. The results also suggest that the spectrum was hardest shortly after the drizzle maximized. No satisfactory source for the enhanced ionization during the poststorm other than particle drizzle could be found that would produce both the magnitude and the diurnal variation of the effect observed, a conclusion which establishes the validity of the hypothesis made

Enhancement of computer program SPECTRAN to provide optional synthesis of 1/12 octave-band and critical-band spectra from 1/3 octave-band spectra

Energy Technology Data Exchange (ETDEWEB)

Chang, Young-Soo [Argonne National Lab., IL (United States); Liebich, R.E. [Raytheon Environmental Services Company, Cambridge, MA (United States)

1997-07-01

This paper describes greatly enhanced version of the computer program SPECTRAN, which was initially presented in Paper No. 96-RA104.01, at the A&WMA 89th Annual Meeting in June 1996. The program has had three basic upgrades since that time. The first is provision of an option to use either batch-mode input from previously prepared data files or a {open_quotes}user-friendly{close_quotes} interactive input routine. The latter is primarily for first-time users and those having only one, or very few, spectra to process. The second improvement is the synthesis of 1/12 octave-band spectra from 1/3 octave-band spectra, with {open_quotes}tone correction,{close_quotes} in a manner similar to that used in the original version of the program. The third fundamental improvement is addition of a unique new capability to synthesize classic {open_quotes}critical-band{close_quotes} spectra from 1/3 octave-band input spectra. Critical-band spectra are also termed {open_quotes}equivalent-rectangular-bandwidth (ERB){close_quotes} and {open_quotes}equal-contribution-to-speech (ECS){close_quotes} spectra.

Band Subset Selection for Hyperspectral Image Classification

Directory of Open Access Journals (Sweden)

Chunyan Yu

2018-01-01

Full Text Available This paper develops a new approach to band subset selection (BSS for hyperspectral image classification (HSIC which selects multiple bands simultaneously as a band subset, referred to as simultaneous multiple band selection (SMMBS, rather than one band at a time sequentially, referred to as sequential multiple band selection (SQMBS, as most traditional band selection methods do. In doing so, a criterion is particularly developed for BSS that can be used for HSIC. It is a linearly constrained minimum variance (LCMV derived from adaptive beamforming in array signal processing which can be used to model misclassification errors as the minimum variance. To avoid an exhaustive search for all possible band subsets, two numerical algorithms, referred to as sequential (SQ and successive (SC algorithms are also developed for LCMV-based SMMBS, called SQ LCMV-BSS and SC LCMV-BSS. Experimental results demonstrate that LCMV-based BSS has advantages over SQMBS.

Competitive behavior of photons contributing to junction voltage jump in narrow band-gap semiconductor multi-quantum-well laser diodes at lasing threshold

Energy Technology Data Exchange (ETDEWEB)

Feng, Liefeng, E-mail: fengliefeng@tju.edu.cn, E-mail: lihongru@nankai.edu.cn; Yang, Xiufang; Wang, Cunda; Yao, Dongsheng [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science, Tianjin University, Tianjin 300072 (China); Li, Yang [Business and Vocational College of Hainan, Haikou 570203 (China); Li, Ding; Hu, Xiaodong [Research Center for Wide Band Gap Semiconductors, State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China); Li, Hongru, E-mail: fengliefeng@tju.edu.cn, E-mail: lihongru@nankai.edu.cn [State Key Laboratory for Medicinal Chemistry and Biology, College of Pharmacy, Nankai University, Tianjin 300071 (China)

2015-04-15

The junction behavior of different narrow band-gap multi-quantum-well (MQW) laser diodes (LDs) confirmed that the jump in the junction voltage in the threshold region is a general characteristic of narrow band-gap LDs. The relative change in the 1310 nm LD is the most obvious. To analyze this sudden voltage change, the threshold region is divided into three stages by I{sub th}{sup l} and I{sub th}{sup u}, as shown in Fig. 2; I{sub th}{sup l} is the conventional threshold, and as long as the current is higher than this threshold, lasing exists and the IdV/dI-I plot drops suddenly; I{sub th}{sup u} is the steady lasing point, at which the separation of the quasi-Fermi levels of electron and holes across the active region (V{sub j}) is suddenly pinned. Based on the evolutionary model of dissipative structure theory, the rate equations of the photons in a single-mode LD were deduced in detail at I{sub th}{sup l} and I{sub th}{sup u}. The results proved that the observed behavior of stimulated emission suddenly substituting for spontaneous emission, in a manner similar to biological evolution, must lead to a sudden increase in the injection carriers in the threshold region, which then causes the sudden increase in the junction voltage in this region.

Competitive behavior of photons contributing to junction voltage jump in narrow band-gap semiconductor multi-quantum-well laser diodes at lasing threshold

International Nuclear Information System (INIS)

Feng, Liefeng; Yang, Xiufang; Wang, Cunda; Yao, Dongsheng; Li, Yang; Li, Ding; Hu, Xiaodong; Li, Hongru

2015-01-01

The junction behavior of different narrow band-gap multi-quantum-well (MQW) laser diodes (LDs) confirmed that the jump in the junction voltage in the threshold region is a general characteristic of narrow band-gap LDs. The relative change in the 1310 nm LD is the most obvious. To analyze this sudden voltage change, the threshold region is divided into three stages by I th l and I th u , as shown in Fig. 2; I th l is the conventional threshold, and as long as the current is higher than this threshold, lasing exists and the IdV/dI-I plot drops suddenly; I th u is the steady lasing point, at which the separation of the quasi-Fermi levels of electron and holes across the active region (V j ) is suddenly pinned. Based on the evolutionary model of dissipative structure theory, the rate equations of the photons in a single-mode LD were deduced in detail at I th l and I th u . The results proved that the observed behavior of stimulated emission suddenly substituting for spontaneous emission, in a manner similar to biological evolution, must lead to a sudden increase in the injection carriers in the threshold region, which then causes the sudden increase in the junction voltage in this region

The Low Band Observatory (LOBO): Expanding the VLA Low Frequency Commensal System for Continuous, Broad-band, sub-GHz Observations

Science.gov (United States)

Kassim, Namir E.; Clarke, Tracy E.; Helmboldt, Joseph F.; Peters, Wendy M.; Brisken, Walter; Hyman, Scott D.; Polisensky, Emil; Hicks, Brian

2015-01-01

The Naval Research Laboratory (NRL) and the National Radio Astronomy Observatory (NRAO) are currently commissioning the VLA Low Frequency Ionosphere and Transient Experiment (VLITE) on a subset of JVLA antennas at modest bandwidth. Its bounded scientific goals are to leverage thousands of JVLA on-sky hours per year for ionospheric and transient studies, and to demonstrate the practicality of a prime-focus commensal system on the JVLA. Here we explore the natural expansion of VLITE to a full-antenna, full-bandwidth Low Band Observatory (LOBO) that would follow naturally from a successful VLITE experience. The new Low Band JVLA receivers, coupled with the existing primary focus feeds, can access two frequency bands: 4 band (54 - 86 MHz) and P band (236-492 MHz). The 4 band feeds are newly designed and now undergoing testing. If they prove successful then they can be permanently mounted at the primary focus, unlike their narrow band predecessors. The combination of Low Band receivers and fixed, primary-focus feeds could provide continuous, broad-band data over two complimentary low-frequency bands. The system would also leverage the relatively large fields-of-view of ~10 degrees at 4 band, and ~2.5 degrees at P band, coupling an excellent survey capability with a natural advantage for serendipitous discoveries. We discuss the compelling science case that flows from LOBO's robust imaging and time domain capabilities coupled with thousands of hours of wide-field, JVLA observing time each year. We also touch on the possibility to incorporate Long Wavelength Array (LWA) stations as additional 'dishes' through the LOBO backend, to improve calibration and sensitivity in LOBO's 4 band.

Decreasing patient identification band errors by standardizing processes.

Science.gov (United States)

Walley, Susan Chu; Berger, Stephanie; Harris, Yolanda; Gallizzi, Gina; Hayes, Leslie

2013-04-01

Patient identification (ID) bands are an essential component in patient ID. Quality improvement methodology has been applied as a model to reduce ID band errors although previous studies have not addressed standardization of ID bands. Our specific aim was to decrease ID band errors by 50% in a 12-month period. The Six Sigma DMAIC (define, measure, analyze, improve, and control) quality improvement model was the framework for this study. ID bands at a tertiary care pediatric hospital were audited from January 2011 to January 2012 with continued audits to June 2012 to confirm the new process was in control. After analysis, the major improvement strategy implemented was standardization of styles of ID bands and labels. Additional interventions included educational initiatives regarding the new ID band processes and disseminating institutional and nursing unit data. A total of 4556 ID bands were audited with a preimprovement ID band error average rate of 9.2%. Significant variation in the ID band process was observed, including styles of ID bands. Interventions were focused on standardization of the ID band and labels. The ID band error rate improved to 5.2% in 9 months (95% confidence interval: 2.5-5.5; P error rates. This decrease in ID band error rates was maintained over the subsequent 8 months.

Interpolation of band-limited discrete-time signals by minimising out-of-band energy

NARCIS (Netherlands)

Janssen, A.J.E.M.; Vries, L.B.

1984-01-01

An interpolation method for restoring burst errors in discrete—time, band—limited signals is presented. The restoration is such that the restored signal has minimal out—of—band energy. The filter coefficients depend Only on the burst length and on the size of the band to which the signal is assumed

Band-gap and band-edge engineering of multicomponent garnet scintillators from first principles

Czech Academy of Sciences Publication Activity Database

Yadav, S.K.; Uberuaga, B.P.; Nikl, Martin; Jiang, C.; Stanek, C.R.

2015-01-01

Roč. 4, č. 5 (2015), "054012-1"-"054012-9" ISSN 2331-7019 R&D Projects: GA ČR GAP204/12/0805 Institutional support: RVO:68378271 Keywords : scintillator * electronic band gap structure * garnets * band gap engineering Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.061, year: 2015

Identification of Nilsson orbitals in the superdeformed minimum of {sup 237}Pu

Energy Technology Data Exchange (ETDEWEB)

Morgan, Thomas James

2008-03-31

In this thesis, a spectroscopy experiment in the second minimum of the double humped fission barrier of {sup 237}Pu is presented, in which, for the first time, single - particle states for a neutron - rich shape isomer with odd neutron number were identified and characterised by their Nilsson quantum numbers. While rotational ({sup 236f}U and {sup 240f}Pu) and vibrational excitations ({sup 240f}Pu) had already been identified earlier in the even-even neighbouring nuclei, now the fission isomers in {sup 237}Pu (t{sub 1/2}=115 ns/1.12 {mu}s) were investigated in a {gamma}-spectroscopy experiment at the Cologne Tandem accelerator. Using the {sup 235}U({alpha},2n) reaction with a pulsed R beam, states in the second minimum were populated. Following the prompt decay of excited states into the ground states of the two shape isomers, the nucleus decays with its halflife, the resulting fission fragments were detected in a specially built 4{pi} parallel plate detector. The extremely rare isomeric {gamma} decays were measured in coincidence with the fission fragments using the highly efficient MINIBALL spectrometer. The background-subtracted {gamma}-ray spectrum was disentangled into contributions from the two shape isomers and 9 excited rotational bands were identified built on the ground states of the two isomers. The ground state spins of the two shape isomers were determined to be I=5/2 (115 ns isomer) and I=9/2 (1120 ns isomer). From the 149 identified {gamma} transitions, independent level schemes were constructed for the two fission isomers in {sup 237}Pu. The consistency of these level schemes was supported by the connecting {gamma} transitions between rotational bands. Furthermore, both level schemes could be combined to a common level scheme, in which the ground state of the long-lived 9/2 isomer was placed 54.0(3) keV above the ground state of the short-lived 5/2 isomer. The resulting level scheme was compared to Hartree-Fock-Bogolyubov single

Treatment of Patellar Lower Pole Fracture with Modified Titanium Cable Tension Band Plus Patellar Tibial Tunnel Steel "8" Reduction Band.

Science.gov (United States)

Li, Jiaming; Wang, Decheng; He, Zhiliang; Shi, Hao

2018-01-08

To determine the efficacy of modified titanium tension band plus patellar tendon tunnel steel 8 "reduction band" versus titanium cable tension band fixation for the treatment of patellar lower pole fracture. 58 patients with lower patella fracture were enrolled in this study, including 30 patients treated with modified titanium cable tension band plus patellar tibial tunnel wire "8" tension band internal fixation (modified group), and 28 patients with titanium cable tension band fixation. All patients were followed up for 9∼15 months with an average of 11.6 months. Knee flexion was significantly improved in the modified group than in the titanium cable tension band group (111.33 ± 13 degrees versus 98.21 ± 21.70 degrees, P = 0.004). The fracture healing time showed no significant difference. At the end of the follow-up, the improvement excellent rate was 93.33% in the modified group, and 82.14% in the titanium cable tension band group. Titanium cable tension band internal fixation loosening was found in 2 cases, including 1 case of treatment by two surgeries without loose internal fixation. The modified titanium cable tension band with "8" tension band fixation showed better efficacy for lower patella fractures than titanium cable tension band fixation.

Global thunderstorm activity estimation based on number of transients in ELF-band

Science.gov (United States)

Ondraskova, Adriena; Sevcik, Sebastian

2017-04-01

Schumann resonances (SR) are resonant electromagnetic oscillations in extremely low frequency band (ELF, 3 Hz - 3 kHz), which arise in the Earth-ionosphere cavity due to lightning activity in planetary range. The time records in the ELF-band consist of background signals and ELF transients/Q-bursts superimposed on the background exceeding it by a factor of 5 - 10. The former are produced by the common worldwide thunderstorm activity (100 - 150 events per second), the latter origin from individual intense distant lightning discharges (100 - 120 powerful strokes per hour). A Q-burst is produced by a combination of direct and antipodal pulses and the decisive factor for its shape follows from the source-to-observer distance. Diurnal/seasonal variations of global thunderstorm activity can be deduced from spectral amplitudes of SR modes. Here we focus on diurnal/seasonal variations of the number of ELF-transients assuming that it is another way of lightning activity estimation. To search for transients, our own code was applied to the SR vertical electric component measured in October 2004 - October 2008 at the Astronomical and Geophysical Observatory of FMPI CU, Slovakia. Criteria for the identification of the burst are chosen on the basis of the transient amplitudes and their morphological features. Monthly mean daily variations in number of transients showed that African focus dominates at 14 - 16 h UT and it is more active in comparison with Asian source, which dominates at 5 - 8 h UT in dependence on winter or summer month. American source had surprisingly slight response. Meteorological observations in South America aiming to determine lightning hotspots on the Earth indicate that flash rate in this region is greatest during nocturnal 0 h - 3 h local standard time. This fact may be interpreted that Asian and South American sources contribute together in the same UT. Cumulative spectral amplitude of the first three SR modes compared with number of ELF-transients in

A UWB Band-Pass Antenna with Triple-Notched Band Using Common Direction Rectangular Complementary Split-Ring Resonators

Directory of Open Access Journals (Sweden)

Bo Yan

2013-01-01

Full Text Available A novel ultrawideband (UWB antenna which has a triple-band notch function is presented. The proposed antenna can block interfering signals from C-band satellite communication systems, IEEE802.11a, and HIPERLAN/2 WLAN systems for example. The antenna is excited by using novel common direction rectangular complementary split-ring resonators (CSRR fabricated on radiating patch of the dielectric substrate with coplanar waveguide (CPW feed strip line. The voltage standing wave ratio (VSWR of the proposed antenna is less than 2.0 in the frequency band from 2.8 to 12 GHz, while showing a very sharp band-rejection performance at 3.9 GHz, 5.2 GHz, and 5.9 GHz. The measurement results show that the proposed antenna provides good omnidirectional field pattern over its whole frequency band excluding the rejected band, which is suitable for UWB applications.

Band-to-Band Misregistration of the Images of MODIS On-Board Calibrators and Its Impact to Calibration

Science.gov (United States)

Wang, Zhipeng; Xiong, Xiaoxiong

2017-01-01

The MODIS instruments aboard Terra and Aqua satellites are radiometrically calibrated on-orbit with a set of onboard calibrators (OBC) including a solar diffuser (SD), a blackbody (BB) and a space view (SV) port through which the detectors can view the dark space. As a whisk-broom scanning spectroradiometer, thirty-six MODIS spectral bands are assembled in the along-scan direction on four focal plane assemblies (FPA). These bands capture images of the same target sequentially with the motion of a scan mirror. Then the images are co-registered on board by delaying appropriate band dependent amount of time depending on the band locations on the FPA. While this co-registration mechanism is functioning well for the "far field" remote targets such as Earth view (EV) scenes or the Moon, noticeable band-to-band misregistration in the along-scan direction has been observed for near field targets, in particular the OBCs. In this paper, the misregistration phenomenon is presented and analyzed. It is concluded that the root cause of the misregistration is that the rotating element of the instrument, the scan mirror, is displaced from the focus of the telescope primary mirror. The amount of the misregistration is proportional to the band location on the FPA and is inversely proportional to the distance between the target and the scan mirror. The impact of this misregistration to the calibration of MODIS bands is discussed. In particular, the calculation of the detector gain coefficient m1 of bands 8-16 (412 nm 870 nm) is improved by up to 1.5% for Aqua MODIS.

47 CFR 15.713 - TV bands database.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false TV bands database. 15.713 Section 15.713... TV bands database. (a) Purpose. The TV bands database serves the following functions: (1) To... databases. (b) Information in the TV bands database. (1) Facilities already recorded in Commission databases...

X-Band CubeSat Communication System Demonstration

Science.gov (United States)

Altunc, Serhat; Kegege, Obadiah; Bundick, Steve; Shaw, Harry; Schaire, Scott; Bussey, George; Crum, Gary; Burke, Jacob C.; Palo, Scott; O'Conor, Darren

2015-01-01

Today's CubeSats mostly operate their communications at UHF- and S-band frequencies. UHF band is presently crowded, thus downlink communications are at lower data rates due to bandwidth limitations and are unreliable due to interference. This research presents an end-to-end robust, innovative, compact, efficient and low cost S-band uplink and X-band downlink CubeSat communication system demonstration between a balloon and a Near Earth Network (NEN) ground system. Since communication systems serve as umbilical cords for space missions, demonstration of this X-band communication system is critical for successfully supporting current and future CubeSat communication needs. This research has three main objectives. The first objective is to design, simulate, and test a CubeSat S- and X-band communication system. Satellite Tool Kit (STK) dynamic link budget calculations and HFSS Simulations and modeling results have been used to trade the merit of various designs for small satellite applications. S- and X-band antennas have been tested in the compact antenna test range at Goddard Space Flight Center (GSFC) to gather radiation pattern data. The second objective is simulate and test a CubeSat compatible X-band communication system at 12.5Mbps including S-band antennas, X-band antennas, Laboratory for Atmospheric and Space Physics (LASP) /GSFC transmitter and an S-band receiver from TRL-5 to TRL-8 by the end of this effort. Different X-band communication system components (antennas, diplexers, etc.) from GSFC, other NASA centers, universities, and private companies have been investigated and traded, and a complete component list for the communication system baseline has been developed by performing analytical and numerical analysis. This objective also includes running simulations and performing trades between different X-band antenna systems to optimize communication system performance. The final objective is to perform an end-to-end X-band CubeSat communication system

High-energy band structure of gold

DEFF Research Database (Denmark)

Christensen, N. Egede

1976-01-01

The band structure of gold for energies far above the Fermi level has been calculated using the relativistic augmented-plane-wave method. The calculated f-band edge (Γ6-) lies 15.6 eV above the Fermi level is agreement with recent photoemission work. The band model is applied to interpret...

Construct and Concurrent Validation of a New Resistance Intensity Scale for Exercise with Thera-Band® Elastic Bands

Directory of Open Access Journals (Sweden)

Juan C. Colado, Xavier Garcia-Masso, N. Travis Triplett, Joaquin Calatayud, Jorge Flandez, David Behm, Michael E. Rogers

2014-12-01

Full Text Available The construct and concurrent validity of the Thera-Band Perceived Exertion Scale for Resistance Exercise with elastic bands (EB was examined. Twenty subjects performed two separate sets of 15 repetitions of both frontal and lateral raise exercise over two sessions. The criterion variables were myoelectric activity and heart rate. One set was performed with an elastic band grip width that permitted 15 maximum repetitions in the selected exercise, and another set was performed with a grip width 50% more than the 15RM grip. Following the final repetition of each set, active muscle (AM and overall body (O ratings of perceived exertion (RPE were collected from the Thera-Band® resistance exercise scale and the OMNI-Resistance Exercise Scale of perceived exertion with Thera-Band® resistance bands (OMNI-RES EB. Construct validity was established by correlating the RPE from the OMNI-RES EB with the Thera-Band RPE scale using regression analysis. The results showed significant differences (p ≤ 0.05 in myoelectric activity, heart rate, and RPE scores between the low- and high-intensity sets. The intraclass correlation coefficient for active muscles and overall RPE scale scores was 0.67 and 0.58, respectively. There was a positive linear relationship between the RPE from the OMNI-RES EB and the Thera-Band scale. Validity coefficients for the RPE AM were r2 = 0.87 and ranged from r2 = 0.76 to 0.85 for the RPE O. Therefore, the Thera-Band Perceived Exertion Scale for Resistance Exercise can be used for monitoring elastic band exercise intensity. This would allow the training dosage to be better controlled within and between sessions. Moreover, the construct and concurrent validity indicates that the OMNI-RES EB measures similar properties of exertion as the Thera-Band RPE scale during elastic resistance exercise.

Design of Dual-Band Two-Branch-Line Couplers with Arbitrary Coupling Coefficients in Bands

Directory of Open Access Journals (Sweden)

I. Prudyus

2014-12-01

Full Text Available A new approach to design dual-band two-branch couplers with arbitrary coupling coefficients at two operating frequency bands is proposed in this article. The method is based on the usage of equivalent subcircuits input reactances of the even-mode and odd-mode excitations. The exact design formulas for three options of the dual-band coupler with different location and number of stubs are received. These formulas permit to obtain the different variants for each structure in order to select the physically realizable solution and can be used in broad range of frequency ratio and power division ratio. For verification, three different dual-band couplers, which are operating at 2.4/3.9 GHz with different coupling coefficients (one with 3/6 dB, and 10/3 dB two others are designed, simulated, fabricated and tested. The measured results are in good agreement with the simulated ones.

The marginal band system in nymphalid butterfly wings.

Science.gov (United States)

Taira, Wataru; Kinjo, Seira; Otaki, Joji M

2015-01-01

Butterfly wing color patterns are highly complex and diverse, but they are believed to be derived from the nymphalid groundplan, which is composed of several color pattern systems. Among these pattern systems, the marginal band system, including marginal and submarginal bands, has rarely been studied. Here, we examined the color pattern diversity of the marginal band system among nymphalid butterflies. Marginal and submarginal bands are usually expressed as a pair of linear bands aligned with the wing margin. However, a submarginal band can be expressed as a broken band, an elongated oval, or a single dot. The marginal focus, usually a white dot at the middle of a wing compartment along the wing edge, corresponds to the pupal edge spot, one of the pupal cuticle spots that signify the locations of color pattern organizing centers. A marginal band can be expressed as a semicircle, an elongated oval, or a pair of eyespot-like structures, which suggest the organizing activity of the marginal focus. Physical damage at the pupal edge spot leads to distal dislocation of the submarginal band in Junonia almana and in Vanessa indica, suggesting that the marginal focus functions as an organizing center for the marginal band system. Taken together, we conclude that the marginal band system is developmentally equivalent to other symmetry systems. Additionally, the marginal band is likely a core element and the submarginal band a paracore element of the marginal band system, and both bands are primarily specified by the marginal focus organizing center.

Block 3 X-band receiver-exciter

Science.gov (United States)

Johns, C. E.

1987-01-01

The development of an X-band exciter, for use in the X-Band Uplink Subsystem, was completed. The exciter generates the drive signal for the X-band transmitter and also generates coherent test signals for the S- and X-band Block 3 translator and a Doppler reference signal for the Doppler extractor system. In addition to the above, the exciter generates other reference signals that are described. Also presented is an overview of the exciter design and some test data taken on the prototype. A brief discussion of the Block 3 Doppler extractor is presented.

Solution conformation and dynamics of a tetrasaccharide related to the LewisX antigen deduced by NMR relaxation measurements

International Nuclear Information System (INIS)

Poveda, Ana; Asensio, Juan Luis; Martin-Pastor, Manuel; Jimenez-Barbero, Jesus

1997-01-01

1 H-NMR cross-relaxation rates and nonselective longitudinal relaxation times have been obtained at two magnetic fields (7.0 and 11.8 T) and at a variety of temperatures for the branched tetrasaccharide methyl 3-O-α-N-acetyl-galactosaminyl-β-galactopyranosyl-(1 → 4)[3-O-α-fucosyl] -glucopyranoside (1), an inhibitor of astrocyte growth. In addition, 13 C-NMR relaxation data have also been recorded at both fields. The 1 H-NMR relaxation data have been interpreted using different motional models to obtain proton-proton correlation times. The results indicate that the GalNAc and Fuc rings display more extensive local motion than the two inner Glc and Gal moieties, since those present significantly shorter local correlation times. The 13 C-NMR relaxation parameters have been interpreted in terms of the Lipari-Szabo model-free approach. Thus, order parameters and internal motion correlation times have been deduced. As obtained for the 1 H-NMR relaxation data, the two outer residues possess smaller order parameters than the two inner rings. Internal correlation times are in the order of 100 ps. The hydroxymethyl groups have also different behaviour,with the exocyclic carbon on the glucopyranoside unit showing the highestS 2 . Molecular dynamics simulations using a solvated system have also been performed and internal motion correlation functions have been deduced from these calculations. Order parameters and interproton distances have been compared to those inferred from the NMR measurements. The obtained results are in fair agreement with the experimental data

Fluctuation diamagnetism in two-band superconductors

Science.gov (United States)

Adachi, Kyosuke; Ikeda, Ryusuke

2016-04-01

Anomalously large fluctuation diamagnetism around the superconducting critical temperature has been recently observed in iron selenide (FeSe) [Kasahara et al. (unpublished)]. This indicates that superconducting fluctuations (SCFs) play a more significant role in FeSe, which supposedly has a two-band structure, than in the familiar single-band superconductors. Motivated by the data on FeSe, SCF-induced diamagnetism is examined in a two-band system, on the basis of a phenomenological approach with a Ginzburg-Landau functional. The obtained results indicate that the SCF-induced diamagnetism may be more enhanced than that in a single-band system due to the existence of two distinct fluctuation modes. Such enhancement of diamagnetism unique to a two-band system seems consistent with the large diamagnetism observed in FeSe, though still far from a quantitative agreement.

U-shaped Relation between Prestimulus Alpha-band and Poststimulus Gamma-band Power in Temporal Tactile Perception in the Human Somatosensory Cortex.

Science.gov (United States)

Wittenberg, Marc André; Baumgarten, Thomas J; Schnitzler, Alfons; Lange, Joachim

2018-04-01

Neuronal oscillations are a ubiquitous phenomenon in the human nervous system. Alpha-band oscillations (8-12 Hz) have been shown to correlate negatively with attention and performance, whereas gamma-band oscillations (40-150 Hz) correlate positively. Here, we studied the relation between prestimulus alpha-band power and poststimulus gamma-band power in a suprathreshold tactile discrimination task. Participants received two electrical stimuli to their left index finger with different SOAs (0 msec, 100 msec, intermediate SOA, intermediate SOA ± 10 msec). The intermediate SOA was individually determined so that stimulation was bistable, and participants perceived one stimulus in half of the trials and two stimuli in the other half. We measured neuronal activity with magnetoencephalography (MEG). In trials with intermediate SOAs, behavioral performance correlated inversely with prestimulus alpha-band power but did not correlate with poststimulus gamma-band power. Poststimulus gamma-band power was high in trials with low and high prestimulus alpha-band power and low for intermediate prestimulus alpha-band power (i.e., U-shaped). We suggest that prestimulus alpha activity modulates poststimulus gamma activity and subsequent perception: (1) low prestimulus alpha-band power leads to high poststimulus gamma-band power, biasing perception such that two stimuli were perceived; (2) intermediate prestimulus alpha-band power leads to low gamma-band power (interpreted as inefficient stimulus processing), consequently, perception was not biased in either direction; and (3) high prestimulus alpha-band power leads to high poststimulus gamma-band power, biasing perception such that only one stimulus was perceived.

Nuclear structure research

International Nuclear Information System (INIS)

Wood, J.L.

1993-01-01

The most significant development this year has been the successful elucidation of the low-energy systematics of the very neutron-deficient Pr, Nd, Pm, and Sm isotopes. This includes an extensive set of Nilsson bandheads in 133 Nd. Some serious errors in earlier decay scheme work were found. The results require some significant reassessments of mean-field calculations in this region. Part of our program continues to focus on shape coexistence and electric monopole (E0) transitions in nuclei. Following the discovery of coexisting ''gamma'' bands connected by E0 transitions in 184 Pt, a similar behavior in 186 Pt was established from 186 Au decay data. This includes a pure E0 transition between states with J π = 3 + , just as was seen in 184 Pt. Progress has been made in elucidating the low-energy systematics of the neutron-deficient Ir isotopes. A search for the population of the superdeformed band in 194 Pb in the decay of 194 Bi was unsuccessful. An extensive program of systematics for nuclei at and near N = Z has been initiated

Electron correlations in narrow band systems

International Nuclear Information System (INIS)

Kishore, R.

1983-01-01

The effect of the electron correlations in narrow bands, such as d(f) bands in the transition (rare earth) metals and their compounds and the impurity bands in doped semiconductors is studied. The narrow band systems is described, by the Hubbard Hamiltonian. By proposing a local self-energy for the interacting electron, it is found that the results are exact in both atomic and band limits and reduce to the Hartree Fock results for U/Δ → 0, where U is the intra-atomic Coulomb interaction and Δ is the bandwidth of the noninteracting electrons. For the Lorentzian form of the density of states of the noninteracting electrons, this approximation turns out to be equivalent to the third Hubbard approximation. A simple argument, based on the mean free path obtained from the imaginary part of the self energy, shows how the electron correlations can give rise to a discontinous metal-nonmetal transition as proposed by Mott. The band narrowing and the existence of the satellite below the Fermi energy in Ni, found in photoemission experiments, can also be understood. (Author) [pt

Epitopes of human testis-specific lactate dehydrogenase deduced from a cDNA sequence

International Nuclear Information System (INIS)

Millan, J.L.; Driscoll, C.E.; LeVan, K.M.; Goldberg, E.

1987-01-01

The sequence and structure of human testis-specific L-lactate dehydrogenase [LDHC 4 , LDHX; (L)-lactate:NAD + oxidoreductase, EC 1.1.1.27] has been derived from analysis of a complementary DNA (cDNA) clone comprising the complete protein coding region of the enzyme. From the deduced amino acid sequence, human LDHC 4 is as different from rodent LDHC 4 (73% homology) as it is from human LDHA 4 (76% homology) and porcine LDHB 4 (68% homology). Subunit homologies are consistent with the conclusion that the LDHC gene arose by at least two independent duplication events. Furthermore, the lower degree of homology between mouse and human LDHC 4 and the appearance of this isozyme late in evolution suggests a higher rate of mutation in the mammalian LDHC genes than in the LDHA and -B genes. Comparison of exposed amino acid residues of discrete anti-genic determinants of mouse and human LDHC 4 reveals significant differences. Knowledge of the human LDHC 4 sequence will help design human-specific peptides useful in the development of a contraceptive vaccine

InfiniBand-Experiences at the Forschungszentrum Karlsruhe

International Nuclear Information System (INIS)

Schwickerath, Ulrich; Heiss, Andreas

2006-01-01

The Institute for Scientific Computing (IWR) at the Forschungszentrum Karlsruhe has been evaluating the InfiniBand [InfiniBand Trade Association, InfiniBand Architecture Specification, Release 1.0, October 24, 2000] technology since end of the year 2002. The performance of the interconnect has been tested on different platforms and architectures using MPI. Sequential file transfer performance was measured with the RFIO protocol running on native InfiniBand [Ulrich Schwickerath, Andreas Heiss, Nucl. Instr. and Meth. A 534 (2004) 130, http://www.fzk.de/infiniband], and a newly developed InfiniBand-enabled version of the XROOTD

Atmospheric response to Saharan dust deduced from ECMWF reanalysis increments

Science.gov (United States)

Kishcha, P.; Alpert, P.; Barkan, J.; Kirchner, I.; Machenhauer, B.

2003-04-01

This study focuses on the atmospheric temperature response to dust deduced from a new source of data - the European Reanalysis (ERA) increments. These increments are the systematic errors of global climate models, generated in reanalysis procedure. The model errors result not only from the lack of desert dust but also from a complex combination of many kinds of model errors. Over the Sahara desert the dust radiative effect is believed to be a predominant model defect which should significantly affect the increments. This dust effect was examined by considering correlation between the increments and remotely-sensed dust. Comparisons were made between April temporal variations of the ERA analysis increments and the variations of the Total Ozone Mapping Spectrometer aerosol index (AI) between 1979 and 1993. The distinctive structure was identified in the distribution of correlation composed of three nested areas with high positive correlation (> 0.5), low correlation, and high negative correlation (Forecast(ECMWF) suggests that the PCA (NCA) corresponds mainly to anticyclonic (cyclonic) flow, negative (positive) vorticity, and downward (upward) airflow. These facts indicate an interaction between dust-forced heating /cooling and atmospheric circulation. The April correlation results are supported by the analysis of vertical distribution of dust concentration, derived from the 24-hour dust prediction system at Tel Aviv University (website: http://earth.nasa.proj.ac.il/dust/current/). For other months the analysis is more complicated because of the essential increasing of humidity along with the northward progress of the ITCZ and the significant impact on the increments.

S-band and X-band integrated PWT photoelectron linacs

International Nuclear Information System (INIS)

Yu, D.; Newsham, D.; Zeng, J.; Rosenzweig, J.

2001-01-01

A compact high-energy injector, which has been developed by DULY Research Inc., will have wide scientific, industrial, and medical applications. The new photoelectron injector integrates the photocathode directly into a multicell linear accelerator. By focusing the beam with solenoids or permanent magnets, and producing high current with low emittance, high brightness and low energy spread are achieved. In addition to providing a small footprint and improved beam quality in an integrated structure, the compact system considerably simplifies external subsystems required to operate the photoelectron linac, including rf power transport, beam focusing, vacuum and cooling. The photoelectron linac employs an innovative Plane-Wave-Transformer (PWT) design, which provides strong cell-to-cell coupling, relaxes manufacturing tolerances and facilitates the attachment of external ports to the compact structure with minimal field interference. DULY Research Inc. under the support of the DOE Small Business Innovation Research (SBIR) program, has developed, constructed and installed a 20-MeV, S-band compact electron source at UCLA. Cold test results for this device are presented. DULY Research is also actively engaged in the development of an X-band photoelectron linear accelerator in a SBIR project. When completed, the higher frequency structure will be approximately three times smaller. Design considerations for this device are discussed following the S-band cold test results

Warm-Up Activities of Middle and High School Band Directors Participating in State-Level Concert Band Assessments

Science.gov (United States)

Ward, Justin P.; Hancock, Carl B.

2016-01-01

The purpose of this study was to examine the warm-ups chosen by concert band directors participating in state-level performance assessments. We observed 29 middle and high school bands and coded the frequency and duration of warm-up activities and behaviors. Results indicated that most bands rehearsed music and played scales, long tones, and…

Does the chromatic Mach bands effect exist?

Science.gov (United States)

Tsofe, Avital; Spitzer, Hedva; Einav, Shmuel

2009-06-30

The achromatic Mach bands effect is a well-known visual illusion, discovered over a hundred years ago. This effect has been investigated thoroughly, mainly for its brightness aspect. The existence of Chromatic Mach bands, however, has been disputed. In recent years it has been reported that Chromatic Mach bands are not perceived under controlled iso-luminance conditions. However, here we show that a variety of Chromatic Mach bands, consisting of chromatic and achromatic regions, separated by a saturation ramp, can be clearly perceived under iso-luminance and iso-brightness conditions. In this study, observers' eye movements were recorded under iso-brightness conditions. Several observers were tested for their ability to perceive the Chromatic Mach bands effect and its magnitude, across different cardinal and non-cardinal Chromatic Mach bands stimuli. A computational model of color adaptation, which predicted color induction and color constancy, successfully predicts this variation of Chromatic Mach bands. This has been tested by measuring the distance of the data points from the "achromatic point" and by calculating the shift of the data points from predicted complementary lines. The results suggest that the Chromatic Mach bands effect is a specific chromatic induction effect.

Behaviour of the Pleistocene marsupial lion deduced from claw marks in a southwestern Australian cave.

Science.gov (United States)

Arman, Samuel D; Prideaux, Gavin J

2016-02-15

The marsupial lion, Thylacoleo carnifex, was the largest-ever marsupial carnivore, and is one of the most iconic extinct Australian vertebrates. With a highly-specialised dentition, powerful forelimbs and a robust build, its overall morphology is not approached by any other mammal. However, despite >150 years of attention, fundamental aspects of its biology remain unresolved. Here we analyse an assemblage of claw marks preserved on surfaces in a cave and deduce that they were generated by marsupial lions. The distribution and skewed size range of claw marks within the cave elucidate two key aspects of marsupial lion biology: they were excellent climbers and reared young in caves. Scrutiny of >10,000 co-located Pleistocene bones reveals few if any marsupial lion tooth marks, which dovetails with the morphology-based interpretation of the species as a flesh specialist.

In-Sample Confidence Bands and Out-of-Sample Forecast Bands for Time-Varying Parameters in Observation Driven Models

NARCIS (Netherlands)

Blasques, F.; Koopman, S.J.; Lasak, K.A.; Lucas, A.

2016-01-01

We study the performances of alternative methods for calculating in-sample confidence and out-of-sample forecast bands for time-varying parameters. The in-sample bands reflect parameter uncertainty, while the out-of-sample bands reflect not only parameter uncertainty, but also innovation

Robust and adaptive band-to-band image transform of UAS miniature multi-lens multispectral camera

Science.gov (United States)

Jhan, Jyun-Ping; Rau, Jiann-Yeou; Haala, Norbert

2018-03-01

Utilizing miniature multispectral (MS) or hyperspectral (HS) cameras by mounting them on an Unmanned Aerial System (UAS) has the benefits of convenience and flexibility to collect remote sensing imagery for precision agriculture, vegetation monitoring, and environment investigation applications. Most miniature MS cameras adopt a multi-lens structure to record discrete MS bands of visible and invisible information. The differences in lens distortion, mounting positions, and viewing angles among lenses mean that the acquired original MS images have significant band misregistration errors. We have developed a Robust and Adaptive Band-to-Band Image Transform (RABBIT) method for dealing with the band co-registration of various types of miniature multi-lens multispectral cameras (Mini-MSCs) to obtain band co-registered MS imagery for remote sensing applications. The RABBIT utilizes modified projective transformation (MPT) to transfer the multiple image geometry of a multi-lens imaging system to one sensor geometry, and combines this with a robust and adaptive correction (RAC) procedure to correct several systematic errors and to obtain sub-pixel accuracy. This study applies three state-of-the-art Mini-MSCs to evaluate the RABBIT method's performance, specifically the Tetracam Miniature Multiple Camera Array (MiniMCA), Micasense RedEdge, and Parrot Sequoia. Six MS datasets acquired at different target distances and dates, and locations are also applied to prove its reliability and applicability. Results prove that RABBIT is feasible for different types of Mini-MSCs with accurate, robust, and rapid image processing efficiency.

Prenatal diagnosis of amniotic band syndrome

Directory of Open Access Journals (Sweden)

Laxmi Devi Padmanabhan

2016-01-01

Full Text Available Amniotic band can cause a broad spectrum of anomalies ranging from simple band constrictions to major craniofacial and visceral defects. It can cause significant neonatal morbidity. Accurate diagnosis will help in the management of the present pregnancy and in counseling with regard to future pregnancies. Here we report three cases of amniotic band syndrome detected in the prenatal period.

Emission bands of phosphorus and calculation of band structure of rare earth phosphides

International Nuclear Information System (INIS)

Al'perovich, G.I.; Gusatinskij, A.N.; Geguzin, I.I.; Blokhin, M.A.; Torbov, V.I.; Chukalin, V.I.; AN SSSR, Moscow. Inst. Novykh Khimicheskikh Problem)

1977-01-01

The method of x-ray emission spectroscopy has been used to investigate the electronic structure of monophosphides of rare-earth metals (REM). The fluorescence K bands of phosphorus have been obtained in LaP, PrP, SmP, GdP, TbP, DyP, HoP, ErP, TmP, YbP, and LuP and also the Lsub(2,3) bands of phosphorus in ErP, TmP, YbP, and LuP. Using the Green function technique involving the muffin-tin potential, the energy spectrum for ErP has been calculated in the single-electron approximation. The hystogram of electronic state distribution N(E) is compared with the experimental K and Lsub(2,3) bands of phosphorus in ErP. The agreement between the main details of N(E) and that of x-ray spectra allows to state that the model used provides a good description of the electron density distribution in crystals of REM monophosphides. In accordance with the character of the N(E) distribution the compounds under study are classified as semimetals or semiconductors with a very narrow forbidden band

The 8th edition of the Table of Isotopes

International Nuclear Information System (INIS)

Firestone, R.B.; Shirley, V.S.; Baglin, C.M.; Chu, S.Y.F.; Zipkin, J.

1997-01-01

A new edition of the Table of Isotopes has been published by John Wiley and Sons, Inc. The two-volume, 3168 page, cloth-bound edition contains nuclear structure and decay data for over 3100 isotopes and isomers. Approximately 24,000 references are cited and the appendices have been updated and expanded. The book is packaged with an interactive CD-ROM that contains the Table of Isotopes in Adobe Acrobat Portable Document Format for convenient viewing on PC and Macintosh personal computers and Unix workstations. The CD-ROM also contains the Table of Superdeformed Nuclear Bands and Fission Isomers; Tables of Atoms, Atomic Nuclei, and Subatomic Particles; the Evaluated Nuclear Structure Data File (ENSDF) and the ENSDF Manual; the Nuclear Science Reference file (NSR); and Adobe Acrobat Reader software. (author)

A comparison of L-band and C-band rf guns as sources for inline-injection systems

International Nuclear Information System (INIS)

Gallardo, J.C.; Kirk, H.G.; Meyerer, T.

1994-12-01

We consider the beam dynamics associated with installing a BNL type 1 1/2 cell L-band or C-band rf gun before two TESLA L-band cryomodules. This system will deliver a 25 MeV electron beam with peak currents on the order of 100 A suitable for further magnetic compression. evaluate the injection systems utilizing the electron beam dynamic code PARMELA from the point of view of minimizing the transverse invariant emittance

Mars Global Surveyor Ka-Band Frequency Data Analysis

Science.gov (United States)

Morabito, D.; Butman, S.; Shambayati, S.

2000-01-01

The Mars Global Surveyor (MGS) spacecraft, launched on November 7, 1996, carries an experimental space-to-ground telecommunications link at Ka-band (32 GHz) along with the primary X-band (8.4 GHz) downlink. The signals are simultaneously transmitted from a 1.5-in diameter parabolic high gain antenna (HGA) on MGS and received by a beam-waveguide (BWG) R&D 34-meter antenna located in NASA's Goldstone Deep Space Network (DSN) complex near Barstow, California. The projected 5-dB link advantage of Ka-band relative to X-band was confirmed in previous reports using measurements of MGS signal strength data acquired during the first two years of the link experiment from December 1996 to December 1998. Analysis of X-band and Ka-band frequency data and difference frequency (fx-fka)/3.8 data will be presented here. On board the spacecraft, a low-power sample of the X-band downlink from the transponder is upconverted to 32 GHz, the Ka-band frequency, amplified to I-W using a Solid State Power Amplifier, and radiated from the dual X/Ka HGA. The X-band signal is amplified by one of two 25 W TWTAs. An upconverter first downconverts the 8.42 GHz X-band signal to 8 GHz and then multiplies using a X4 multiplier producing the 32 GHz Ka-band frequency. The frequency source selection is performed by an RF switch which can be commanded to select a VCO (Voltage Controlled Oscillator) or USO (Ultra-Stable Oscillator) reference. The Ka-band frequency can be either coherent with the X-band downlink reference or a hybrid combination of the USO and VCO derived frequencies. The data in this study were chosen such that the Ka-band signal is purely coherent with the X-band signal, that is the downconverter is driven by the same frequency source as the X-band downlink). The ground station used to acquire the data is DSS-13, a 34-meter BWG antenna which incorporates a series of mirrors inside beam waveguide tubes which guide the energy to a subterranean pedestal room, providing a stable environment

Adhesives for fixed orthodontic bands.

Science.gov (United States)

Millett, Declan T; Glenny, Anne-Marie; Mattick, Rye Cr; Hickman, Joy; Mandall, Nicky A

2016-10-25

Orthodontic treatment involves using fixed or removable appliances (dental braces) to correct the positions of teeth. It has been shown that the quality of treatment result obtained with fixed appliances is much better than with removable appliances. Fixed appliances are, therefore, favoured by most orthodontists for treatment. The success of a fixed orthodontic appliance depends on the metal attachments (brackets and bands) being attached securely to the teeth so that they do not become loose during treatment. Brackets are usually attached to the front and side teeth, whereas bands (metal rings that go round the teeth) are more commonly used on the back teeth (molars). A number of adhesives are available to attach bands to teeth and it is important to understand which group of adhesives bond most reliably, as well as reducing or preventing dental decay during the treatment period. To evaluate the effectiveness of the adhesives used to attach bands to teeth during fixed appliance treatment, in terms of:(1) how often the bands come off during treatment; and(2) whether they protect the banded teeth against decay during fixed appliance treatment. The following electronic databases were searched: Cochrane Oral Health's Trials Register (searched 2 June 2016), Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 5) in the Cochrane Library (searched 2 June 2016), MEDLINE Ovid (1946 to 2 June 2016) and EMBASE Ovid (1980 to 2 June 2016). We searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. Randomised and controlled clinical trials (RCTs and CCTs) (including split-mouth studies) of adhesives used to attach orthodontic bands to molar teeth were selected. Patients with full arch fixed orthodontic appliance(s) who had bands attached to molars were included. All review authors

Design of an S band narrow-band bandpass BAW filter

Science.gov (United States)

Gao, Yang; Zhao, Kun-li; Han, Chao

2017-11-01

An S band narrowband bandpass filter BAW with center frequency 2.460 GHz, bandwidth 41MHz, band insertion loss - 1.154 dB, the passband ripple 0.9 dB, the out of band rejection about -42.5dB@2.385 GHz; -45.5dB@2.506 GHz was designed for potential UAV measurement and control applications. According to the design specifications, the design is as follows: each FBAR's stack was designed in BAW filter by using Mason model. Each FBAR's shape was designed with the method of apodization electrode. The layout of BAW filter was designed. The acoustic-electromagnetic cosimulation model was built to validate the performance of the designed BAW filter. The presented design procedure is a common one, and there are two characteristics: 1) an A and EM co-simulation method is used for the final BAW filter performance validation in the design stage, thus ensures over-optimistic designs by the bare 1D Mason model are found and rejected in time; 2) An in-house developed auto-layout method is used to get compact BAW filter layout, which simplifies iterative error-and-try work here and output necessary in-plane geometry information to the A and EM cosimulation model.

Location of the valence band maximum in the band structure of anisotropic 1 T'-ReSe2

Science.gov (United States)

Eickholt, P.; Noky, J.; Schwier, E. F.; Shimada, K.; Miyamoto, K.; Okuda, T.; Datzer, C.; Drüppel, M.; Krüger, P.; Rohlfing, M.; Donath, M.

2018-04-01

Transition-metal dichalcogenides (TMDCs) are a focus of current research due to their fascinating optical and electronic properties with possible technical applications. ReSe2 is an interesting material of the TMDC family, with unique anisotropic properties originating from its distorted 1 T structure (1 T '). To develop a fundamental understanding of the optical and electric properties, we studied the underlying electronic structure with angle-resolved photoemission (ARPES) as well as band-structure calculations within the density functional theory (DFT)-local density approximation (LDA) and GdW approximations. We identified the Γ ¯M¯1 direction, which is perpendicular to the a axis, as a distinct direction in k space with the smallest bandwidth of the highest valence band. Using photon-energy-dependent ARPES, two valence band maxima are identified within experimental limits of about 50 meV: one at the high-symmetry point Z , and a second one at a non-high-symmetry point in the Brillouin zone. Thus, the position in k space of the global valence band maximum is undecided experimentally. Theoretically, an indirect band gap is predicted on a DFT-LDA level, while quasiparticle corrections lead to a direct band gap at the Z point.

8-band and 14-band kp modeling of electronic band structure and material gain in Ga(In)AsBi quantum wells grown on GaAs and InP substrates

Energy Technology Data Exchange (ETDEWEB)

Gladysiewicz, M.; Wartak, M. S. [Faculty of Fundamental Problems of Technology, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Department of Physics and Computer Science, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5 (Canada); Kudrawiec, R. [Faculty of Fundamental Problems of Technology, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland)

2015-08-07

The electronic band structure and material gain have been calculated for GaAsBi/GaAs quantum wells (QWs) with various bismuth concentrations (Bi ≤ 15%) within the 8-band and 14-band kp models. The 14-band kp model was obtained by extending the standard 8-band kp Hamiltonian by the valence band anticrossing (VBAC) Hamiltonian, which is widely used to describe Bi-related changes in the electronic band structure of dilute bismides. It has been shown that in the range of low carrier concentrations n < 5 × 10{sup 18 }cm{sup −3}, material gain spectra calculated within 8- and 14-band kp Hamiltonians are similar. It means that the 8-band kp model can be used to calculate material gain in dilute bismides QWs. Therefore, it can be applied to analyze QWs containing new dilute bismides for which the VBAC parameters are unknown. Thus, the energy gap and electron effective mass for Bi-containing materials are used instead of VBAC parameters. The electronic band structure and material gain have been calculated for 8 nm wide GaInAsBi QWs on GaAs and InP substrates with various compositions. In these QWs, Bi concentration was varied from 0% to 5% and indium concentration was tuned in order to keep the same compressive strain (ε = 2%) in QW region. For GaInAsBi/GaAs QW with 5% Bi, gain peak was determined to be at about 1.5 μm. It means that it can be possible to achieve emission at telecommunication windows (i.e., 1.3 μm and 1.55 μm) for GaAs-based lasers containing GaInAsBi/GaAs QWs. For GaInAsBi/Ga{sub 0.47}In{sub 0.53}As/InP QWs with 5% Bi, gain peak is predicted to be at about 4.0 μm, i.e., at the wavelengths that are not available in current InP-based lasers.

Atmospheric response to Saharan dust deduced from ECMWF reanalysis (ERA) temperature increments

Science.gov (United States)

Kishcha, P.; Alpert, P.; Barkan, J.; Kirchner, I.; Machenhauer, B.

2003-09-01

This study focuses on the atmospheric temperature response to dust deduced from a new source of data the European Reanalysis (ERA) increments. These increments are the systematic errors of global climate models, generated in the reanalysis procedure. The model errors result not only from the lack of desert dust but also from a complex combination of many kinds of model errors. Over the Sahara desert the lack of dust radiative effect is believed to be a predominant model defect which should significantly affect the increments. This dust effect was examined by considering correlation between the increments and remotely sensed dust. Comparisons were made between April temporal variations of the ERA analysis increments and the variations of the Total Ozone Mapping Spectrometer aerosol index (AI) between 1979 and 1993. The distinctive structure was identified in the distribution of correlation composed of three nested areas with high positive correlation (>0.5), low correlation and high negative correlation (Forecast (ECMWF) suggest that the PCA (NCA) corresponds mainly to anticyclonic (cyclonic) flow, negative (positive) vorticity and downward (upward) airflow. These findings are associated with the interaction between dust-forced heating/cooling and atmospheric circulation. This paper contributes to a better understanding of dust radiative processes missed in the model.

The complex band structure for armchair graphene nanoribbons

International Nuclear Information System (INIS)

Zhang Liu-Jun; Xia Tong-Sheng

2010-01-01

Using a tight binding transfer matrix method, we calculate the complex band structure of armchair graphene nanoribbons. The real part of the complex band structure calculated by the transfer matrix method fits well with the bulk band structure calculated by a Hermitian matrix. The complex band structure gives extra information on carrier's decay behaviour. The imaginary loop connects the conduction and valence band, and can profoundly affect the characteristics of nanoscale electronic device made with graphene nanoribbons. In this work, the complex band structure calculation includes not only the first nearest neighbour interaction, but also the effects of edge bond relaxation and the third nearest neighbour interaction. The band gap is classified into three classes. Due to the edge bond relaxation and the third nearest neighbour interaction term, it opens a band gap for N = 3M − 1. The band gap is almost unchanged for N = 3M + 1, but decreased for N = 3M. The maximum imaginary wave vector length provides additional information about the electrical characteristics of graphene nanoribbons, and is also classified into three classes

Band to Band Tunneling (BBT) Induced Leakage Current Enhancement in Irradiated Fully Depleted SOI Devices

Science.gov (United States)

Adell, Phillipe C.; Barnaby, H. J.; Schrimpf, R. D.; Vermeire, B.

2007-01-01

We propose a model, validated with simulations, describing how band-to-band tunneling (BBT) affects the leakage current degradation in some irradiated fully-depleted SOI devices. The dependence of drain current on gate voltage, including the apparent transition to a high current regime is explained.

Time-odd mean fields in covariant density functional theory: Rotating systems

International Nuclear Information System (INIS)

Afanasjev, A. V.; Abusara, H.

2010-01-01

Time-odd mean fields (nuclear magnetism) and their impact on physical observables in rotating nuclei are studied in the framework of covariant density functional theory (CDFT). It is shown that they have profound effect on the dynamic and kinematic moments of inertia. Particle number, configuration, and rotational frequency dependencies of their impact on the moments of inertia have been analyzed in a systematic way. Nuclear magnetism can also considerably modify the band crossing features such as crossing frequencies and the properties of the kinematic and dynamic moments of inertia in the band crossing region. The impact of time-odd mean fields on the moments of inertia in the regions away from band crossing only weakly depends on the relativistic mean-field parametrization, reflecting good localization of the properties of time-odd mean fields in CDFT. The moments of inertia of normal-deformed nuclei considerably deviate from the rigid-body value. On the contrary, superdeformed and hyperdeformed nuclei have the moments of inertia which are close to rigid-body value. The structure of the currents in rotating frame, their microscopic origin, and the relations to the moments of inertia have been systematically analyzed. The phenomenon of signature separation in odd-odd nuclei, induced by time-odd mean fields, has been analyzed in detail.

Formation of Degenerate Band Gaps in Layered Systems

Directory of Open Access Journals (Sweden)

Alexey P. Vinogradov

2012-06-01

Full Text Available In the review, peculiarities of spectra of one-dimensional photonic crystals made of anisotropic and/or magnetooptic materials are considered. The attention is focused on band gaps of a special type—the so called degenerate band gaps which are degenerate with respect to polarization. Mechanisms of formation and properties of these band gaps are analyzed. Peculiarities of spectra of photonic crystals that arise due to the linkage between band gaps are discussed. Particularly, it is shown that formation of a frozen mode is caused by linkage between Brillouin and degenerate band gaps. Also, existence of the optical Borrmann effect at the boundaries of degenerate band gaps and optical Tamm states at the frequencies of degenerate band gaps are analyzed.

Study of rotational band in 111Sn

International Nuclear Information System (INIS)

Ganguly, S.; Banerjee, P.; Ray, I.; Kshetri, R.; Raut, R.; Goswami, A.; Saha Sarkar, M.; Bhattacharya, S.; Mukherjee, A.; Mukherjee, G.; Basu, S.K.; Mukhopadhyay, S.

2006-01-01

The motivation of the present work is to study the negative-parity rotational band in 111 Sn. Study of the lifetimes of the states of the rotational band is expected to provide information on their structures as well as the band termination phenomenon

Synthesis and design of waveguide band-stop filters without out-of-band spurious responses for plasma diagnosis

Energy Technology Data Exchange (ETDEWEB)

Montejo-Garai, Jose R., E-mail: jr@etc.upm.es [Departamento de Electromagnetismo y Teoria de Circuitos, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, Madrid 20840 (Spain); Leal-Sevillano, Carlos A. [Departamento de Electromagnetismo y Teoria de Circuitos, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, Madrid 20840 (Spain); Ruiz-Cruz, Jorge A. [Escuela Politecnica Superior, Universidad Autonoma de Madrid, C/Fco. Tomas y Valiente 11, Madrid 28409 (Spain); Rebollar, Jesus M. [Departamento de Electromagnetismo y Teoria de Circuitos, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, Madrid 20840 (Spain); Estrada, Teresa [T. Laboratorio Nacional de Fusion, Asociacion Euratom-CIEMAT, Madrid 28040 (Spain)

2012-09-15

Highlights: Black-Right-Pointing-Pointer A rigorous systematic design process based on circuit synthesis is proposed for band-stop filters. Black-Right-Pointing-Pointer The new compact E-plane waveguide structure reduces drastically the unwanted resonances in a very large pass band. Black-Right-Pointing-Pointer The manufacturing process together with the computation effort is significantly reduced. Black-Right-Pointing-Pointer Experimental results validate the state-of-art electrical responses. - Abstract: Band-stop or notch filters play a crucial role in plasma diagnosis systems to protect receivers from the stray radiation. In this work, a rigorous design process based on circuit synthesis in addition to an extremely compact E-plane waveguide structure is proposed for this kind of filters. On the one hand, the transfer function verifying the rejection specification is analytically obtained, fixing the minimum number of required cavities. On the other hand, a coupling structure that reduces drastically the unwanted resonances in filters with a very large pass band requirement, is presented. This coupling between the rejection cavities and the main rectangular waveguide has additional advantages; (a) unlike typical inductive irises, large coupling coefficients can be implemented (b) a pure E-plane configuration is achieved, which simplifies the manufacturing and also reduces significantly the computational effort. Experimental validation is demonstrated by two pseudo-elliptic fifth-order band-stop filters fabricated and measured in Ka and V bands. In both cases, the filters are free of spurious resonances in their total operation bands.