Sample records for e3-transitions

  1. E3-transitions in sup(105, 107, 109, 111)Ag

    International Nuclear Information System (INIS)

    Shevelev, G.A.; Troitskaya, A.G.; Kartashov, V.M.


    Electron radiation of the isomeric transitions of the sup(105-111)Ag odd nuclei was studied using an iron magnetic πsup(√2) beta spectrometer. For most isomeric transitions, relative intensities of the K, L, M, and N lines have been measured; for sup(105-111)Ag and 111 Cd they were measured for the first time. Energy of gamma transitions, relative intensities of internal conversion electrons (ICE) compared with the theoretical ICE values for the E3 transitions are presented. The observations for all the shells are in a fairly gool agreement with the calculations. Systematics of low-lying excited states of the silver nuclei involved is proposed. It has been established that spins and parities of the first excited states of the sup(105-111)Ag odd nuclei are 7/2 + . Multipolarities of isomeric transitions from these staes are pure E3. Spin and parity 9/2 + of the second excited states may be uniquely determined unly for 109 Ag from direct measurements of the ICE transition at 45.8 keV

  2. Spectroscopy of 215Ra: the shell model and enhanced E3 transitions

    International Nuclear Information System (INIS)

    Stuchbery, A.E.; Dracoulis, G.D.; Kibedi, T.; Fabricius, B.; Lane, G.J.; Poletti, A.R.; Baxter, A.M.


    Excited states in the N=127 nucleus 215 Ra have been studied using γ-ray and electron spectroscopy following reactions of 13 C on 206 Pb targets. Levels were identified up to spins of ∝61/2 ℎ and excitation energies of ∝6 MeV. Enhanced octupole transitions are a feature of the level scheme. Lifetimes and magnetic moments were measured for several isomeric levels. The level scheme, transition rates and magnetic moments are compared with empirical shell model calculations and multiparticle octupole-coupled shell model calculations. In general, the experimental data are well described, but in comparison with its success in describing enhanced E3 transitions between related states in the radon isotopes, some limitations of the multiparticle octupole-coupling approach are revealed in 215 Ra. (orig.)

  3. Two- to one-phonon E3 transition strength in {sup 148}Gd

    Energy Technology Data Exchange (ETDEWEB)

    Piiparinen, M [Niels Bohr Institute, Tandem Accelerator Laboratory, Roskilde (Denmark); [Jyvaeskylae Univ. (Finland). Dept. of Physics; Atac, A; Nyberg, J; Ramsoy, T; Sletten, G [Niels Bohr Institute, Tandem Acceleratory Laboratory, Roskile, (Denmark); Virtanen, A; Muller, D [Jyvaeskylae Univ. (Finland). Dept. of Physics; Kleinheinz, P [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Blomqvist, J [Manne Siegbahn Inst. of Physics, Stockholm (Sweden)


    In a plunger experiment the mean life of the ({nu} f{sub 6}{sup 2}x3{sup -}x3{sup -})12{sup +} state at 3.981 MeV in {sub 64}{sup 148}Gd{sub 84} was measured as {tau}=83(10)ps, giving 77(11)B{sub w} for the 1286 keV 12{sup +} {yields} 9{sup -} E3 transition rate, which confirms the double-octupole character of the 12{sup +} state. The observed deviations in energy and transition rate from harmonic vibration are shown to be caused by the exclusion principle acting between nucleons in the two phonons and are related to the dominant contributions to the {sup 148}Gd octupole phonon of the low-lying {Delta}l={Delta}j=3 proton- and neutron in-shell 3{sup -} excitations which are of vital significance for the octupole mode in open-shell nuclei. (author). 17 refs., 2 figs.

  4. Magnetic moments, E3 transitions and the structure of high spin core excited states in 211Rn

    International Nuclear Information System (INIS)

    Poletti, A.R.; Dracoulis, G.D.; Byrne, A.P.; Stuchbery, A.E.; Poletti, S.J.; Gerl, J.; Lewis, P.M.


    The results of g-factor measurements of high spin states in 211 Rn are: Esub(x)=8856+Δsup(') keV (Jsup(π)=63/2 - ), g=0.626(7); 6101+Δsup(') keV (49/2 + ), 0.766(8); 5247+Δsup(') keV (43/2 - ), 0.74(2); 3927+Δsup(') keV (35/2 + ), 1/017(12); 1578+Δsup(') keV (17/2 - ), 0.912(9). These results together with measured E3 transition strengths and shell model calculations are used to assign configurations to the core excited states in 211 Rn. Mixed configurations are required to explain the g-factors and enhanced E3 strengths simultaneously

  5. Magnetic moments, E3 transitions and the structure of high-spin core excited states in 211Rn

    International Nuclear Information System (INIS)

    Poletti, A.R.; Dracoulis, G.D.; Byrne, A.P.; Stuchbery, A.E.; Poletti, S.J.; Gerl, J.; Lewis, P.M.


    The results of g-factor measurements of high-spin states in 211 Rn are: Esub(x)=8856+Δ' keV (Jsup(π)=63/2 - ), g=0.626(7); 6101+Δ' keV (49/2 + ), 0.766(8); 5347+Δ' keV (43/2 - ), 0.74(2); 3927+Δ keV (35/2 + ), 1.017(12); 1578+Δ keV (17/2 - ), 0.912(9). These results together with measured E3 transition strengths and shell model calculations are used to assign configurations to the core excited states in 211 Rn. Mixed configurations are required to explain the g-factors and enhanced E3 strengths simultaneously. (orig.)

  6. Enhanced E3 transitions and mixed configurations for core excited isomers in 210At and 211At

    International Nuclear Information System (INIS)

    Dracoulis, G.D.; Steed, C.A.; Byrne, A.P.; Poletti, S.J.; Stuchbery, A.E.; Bark, R.A.


    The lifetime and branching ratio of the 19 + isomer in 210 At have been measured. Its enhanced E3 decay and g-factor, and those of the related 39/2 - isomer in 211 At are compared with the results of a semi-empirical shell model calculation which includes couplings to the 3 - octupole vibration, resulting in mixed configurations. Lifetimes were also obtained for the 15 - isomer in 210 At, and he 29/2 + isomer in 209 At

  7. Spectroscopy of high spin states in sup(211,212,213)Fr

    International Nuclear Information System (INIS)

    Byrne, A.P.; Dracoulis, G.D.; Fahlander, C.; Hubel, H.; Poletti, A.R.; Stuchbery, A.E.; Gerl, J.; Davie, R.F.; Poletti, S.J.


    The level structures of 211 Fr, 212 Fr and 213 Fr have been observed to high spins, approx. 28(h/2π) (and excitation energies approx. 8 MeV) using a variety of gamma-ray spectroscopic techniques. The structure of these nuclides is discussed in terms of couplings of single particle states through empirical shell model calculations. Good agreement with experiment is obtained. In 212 Fr and 213 Fr core-excited configurations are required to explain the properties of the highest states. A number of long lived states were observed in each nucleus some of which decay by by enhanced E3 transitions. The E3 transition strengths are discussed

  8. Radiative width of molecular-cluster states

    International Nuclear Information System (INIS)

    Alhassid, Y.; Gai, M.; Bertsch, G.F.


    Molecular states are characterized by enhanced electromagnetic deexcitations of many different multipolarities. The expected enhancement of E1, E2, and E3 transitions is examined by deriving molecular sum rules for radiative deexcitation widths and via a dimensionality approach. The enhancement of the E1 transitions is the most striking

  9. High spin states and Yrast isomers in 211Rn

    International Nuclear Information System (INIS)

    Poletti, A.R.; Dracoulis, G.D.; Fahlander, C.; Morrison, I.


    Excited states in 211 Rn with spins up to 53/2 have been identified using (HI,xn) reactions and γ-ray techniques. A shell model calculation can reproduce the ordering of the yrast sequence up to spin 41/2 - . Several yrast isomers have been identified. Enhanced E3 transitions are observed and their systematic occurrence in this region discussed. The influence of the neutron hole, and possible core excitations on the effective moment of inertia are also pointed out

  10. High spin states and yrast isomers in 211Rn

    International Nuclear Information System (INIS)

    Poletti, A.R.; Dracoulis, G.D.; Fahlander, C.; Morrison, I.


    Excited states in 211 Rn with spins up to 53/2 have been identified using (HI,xn) reactions and γ-ray techniques. A shell model calculation can reproduce the ordering of the yrast sequence up to spin 41/2. Several yrast isomers have been identified. Enhanced E3 transitions are observed and their systematic occurrence in this region discussed. The influence of the neutron hole, and possible core excitations on the effective moment of inertia are also pointed out

  11. Octupole excitations in 146Sm

    International Nuclear Information System (INIS)

    Bizzeti, P.G.; Bizzetti-Sona, A.M.


    The mean lives of the lowest 9 - and 12 + states of 146 Sm have been measured by means of the RDM. Their (preliminary) values are r m (9 - )=0.97±0.05 ns and r m (12 + )=15±2 ps, respectively. The strengths of the collective E3 transitions of the 12 + →9 - →6 6 cascade are compared with the corresponding ones in 148 Gd

  12. Enhanced population of side band of {sup 155}Gd in heavy-ion Coulomb excitation

    Energy Technology Data Exchange (ETDEWEB)

    Oshima, Masumi; Hayakawa, Takehito; Hatsukawa, Yuichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; and others


    In the Coulomb excitation of {sup 155}Gd with heavy projectiles, {sup 32}S, {sup 58}Ni and {sup 90}Zr, unexpectedly large enhancement of a positive-parity side band has been observed. This enhancement could not be reproduced by a Coulomb-excitation calculation taking into account the recommended upper limits of E1 or E3 transitions, which are compiled in the whole mass region, and is proportional to the electric field accomplished in the Coulomb-scattering process. (author)

  13. Total conversion coefficient of the 185 keV (10--7+) transition in sup(182m)Ta

    International Nuclear Information System (INIS)

    Suryanarayana, Ch.; Venkateswara Rao, N.; Raghavaiah, C.V.; Bhuloka Reddy, S.; Satyanarayana, G.; Sastry, D.L.


    The total conversion coefficient of the 185 keV (E3) isomeric transition in 182 Ta was measured for the first time using gamma intensity balance method. The experimental αsub(T) was obtained as 3.4 ± 0.2 consistent with the theoretical value (3.272) due to Rosel et al. The E3 transition probability was found to be hindered by a factor of 5.07x10 4 when compared to the single particle estimate. (author). 13 refs

  14. Structure of high-spin isomers in trans-lead nuclei

    International Nuclear Information System (INIS)

    Dracoulis, G.D.


    The structure of core-excited high-spin isomers in the N ≤ 126 isotopes of At, Rn and Fr is reviewed. New results for high-spin states in 211 Rn and 212 Rn, approaching the limit of the available angular momentum from the valence particles, are presented. The recurring experimental feature is decay by very enhanced E3 transitions. These, and other properties are explained in a natural way by inclusion of particle-octupole vibration coupling, in a semi-empirical shell model. The deformed independent particle model is not successful in explaining these features. 40 refs., 4 tabs., 11 figs

  15. High-spin yrast isomers in 211Rn and 212Rn with enhanced E3 decays

    International Nuclear Information System (INIS)

    Dracoulis, G.D.; Byrne, A.P.; Fabricius, B.


    New isomeric states with J π =69/2 + ,τ m = 13 (1) ns in 211 Rn and J π =33 - ,τ m = 7(1) ns in 212 Rn have been identified. They decay by enchanced E3 transitions with strengths of 33(3) and 43(6) single particle units to the known 63/2 - and 30 + isomers 211 Rn and 212 Rn, respectively. The excitation energies and transition strengths agree well with predictions of the multi-particle, octupole-vibration coupled model. 13 refs., 2 tabs., 3 figs

  16. Medium-spin levels and the character of the 20.4 ns 13/2+ isomer in 145Gd

    International Nuclear Information System (INIS)

    Pakkanen, A.; Muhonen, J.; Piiparinen, M.


    Levels of the N = 81 nucleus 145 Gd have been investigated by in-beam γ-ray and conversion electron spectroscopy with the 144 Sm( 3 He,2n) reaction. Fourteen new low- and medium-spin states between 1.0 and 2.4 MeV excitation, the known yrast levels up to spin (21/2) + , five other high-spin non-yrast states and a new 20.4 ns (13/2) + isomer at 2200.2 keV in 145 Gd have been observed. The isomer decays via a fast 927.3 keV E3 transition with B(E3) = 48 +- 7 W.u. Another weaker decay branch is a mixed, strongly hindered E1+M2+E3 transition to the νhsub(11/2)sup(-1) state. We propose an octupole νfsub(7/2)jsub(0)sup(-2)x3 - main configuration for the isomer, analogous to the 997 keV (13/2) + isomer in 147 Gd. The levels of 145 Gd are discussed on the basis of the spherical shell model. (author)

  17. Level structure of 60Ni from the 58Ni(α,2p#betta#) reaction

    International Nuclear Information System (INIS)

    Chan, T.U.; Morand, C.; Azgui, F.


    The 60 Ni nucleus has been studied via the 58 Ni (α, 2p#betta#) reaction at Esub(α)=32 MeV using in-beam #betta# spectroscopy techniques. High-spin states up to 10 MeV excitation have been established. Among the 5 branches depopulating the Yrast Jsup(π)=7 - state, has been found an E3 transition down to the 4 + state. Comparison with direct reaction results leads to assign very probably the [#betta#fsub(5/2),#betta#gsub(9/2)] 7 - configuration to the Jsup(π)=7 - Yrast state at 5349 keV. Other high-spin states might be accounted for by the breaking of the 56 Ni core

  18. Measurements of octupole collectivity in Rn and Ra nuclei using Coulomb excitation

    CERN Multimedia

    We propose to exploit the unique capability of HIE-ISOLDE to provide post-accelerated $^{221,222}$Rn and $^{222,226,228}$Ra ion beams for the study of octupole collectivity in these nuclei. We will measure E3 transition moments in $^{222}$Rn and $^{222,226,228}$Ra in order to fully map out the variation in E3 strength in the octupole mass region with Z$\\thicksim$88 and N$\\thicksim$134. This will validate model calculations that predict different behaviour as a function of N. We will also locate the position of the parity doublet partner of the ground state in $^{221}$Rn, in order to test the suitability of odd-A radon isotopes for EDM searches.

  19. Enhancement of octupole strength in near spherical nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Robledo, L.M. [Universidad Autonoma de Madrid, Dep. Fisica Teorica, Facultad de Ciencias, Madrid (Spain)


    The validity of the rotational formula used to compute E1 and E3 transition strengths in even-even nuclei is analyzed within the Generator Coordinate Method framework based on mean field wave functions. It turns out that those nuclei with spherical or near spherical shapes the E1 and E3 strengths computed with this formula are strongly underestimated and a sound evaluation of them requires angular-momentum projected wave functions. Results for several isotopic chains with proton number equal to or near magic numbers are analyzed and compared with experimental data. The use of angular-momentum projected wave functions greatly improves the agreement with the scarce experimental data. (orig.)

  20. Nonradiative excitation of the muonic atom 238U as an inverse conversion process

    International Nuclear Information System (INIS)

    Karpeshin, F.F.; Nesterenko, V.U.


    The probabilities of nonradiation nuclear excitation are calculated for different muon transitions in the muonic atom 238 U. Microscopic nuclear wave functions, obtained within the quasiparticle-phonon nuclear model and the muonic conversion coefficients have been used. The probability of nonradiation nuclear excitation for the muonic transitions 2p → 1s and 3p → 1s has been found to be equal to 0.3. It is predicted that nonradiative E3 transitions 3d → 2p can take place with the probability 0.08-0.10. The dynamic effect of nuclear structure on the probability of nonradiative nuclear excitation is taken into account. The estimates of 238 U fissility fission branching at nonradiation transitions are also obtained

  1. Prompt and delayed spectroscopy of At203 : Observation of a shears band and a 29/2+ isomeric state

    Energy Technology Data Exchange (ETDEWEB)

    Auranen, K.; Uusitalo, J.; Juutinen, S.; Badran, H.; Defranchi Bisso, F.; Cox, D.; Grahn, T.; Greenlees, P. T.; Herzáň, A.; Jakobsson, U.; Julin, R.; Konki, J.; Leino, M.; Lightfoot, A.; Mallaburn, M. J.; Neuvonen, O.; Pakarinen, J.; Papadakis, P.; Partanen, J.; Rahkila, P.; Sandzelius, M.; Sarén, J.; Scholey, C.; Sorri, J.; Stolze, S.; Wang, Y. K.


    Using fusion-evaporation reactions, a gas-filled recoil separator, recoil-gating technique and recoil-isomer decay tagging technique we have extended the level scheme of At-203 (N = 118) significantly. We have observed an isomeric [tau = 14.1(3) mu s] state with a spin and parity of 29/2(+). The isomeric state is suggested to originate from the pi(h(9/2)) circle times |Po-202; 11(-)> coupling, and it is depopulated through 286 keV E2 and 366 keV E3 transitions. In addition, we have observed a cascade of magnetic-dipole transitions which is suggested to be generated by the shears mechanism.

  2. Fast-timing lifetime measurements of excited states in Cu67 (United States)

    NiÅ£ǎ, C. R.; Bucurescu, D.; Mǎrginean, N.; Avrigeanu, M.; Bocchi, G.; Bottoni, S.; Bracco, A.; Bruce, A. M.; Cǎta-Danil, G.; Coló, G.; Deleanu, D.; Filipescu, D.; GhiÅ£ǎ, D. G.; Glodariu, T.; Leoni, S.; Mihai, C.; Mason, P. J. R.; Mǎrginean, R.; Negret, A.; Pantelicǎ, D.; Podolyak, Z.; Regan, P. H.; Sava, T.; Stroe, L.; Toma, S.; Ur, C. A.; Wilson, E.


    The half-lives of the 9/2+, 13/2+, and 15/2+ yrast states in the neutron-rich Cu67 nucleus were determined by using the in-beam fast-timing technique. The experimentally deduced E3 transition strength for the decay of the 9/2+ level to the 3/2- ground state indicates that the wave function of this level might contain a collective component arising from the coupling of the odd proton p3/2 with the 3- state in Ni66. Theoretical interpretations of the 9/2+ state are presented within the particle-vibration weak-coupling scheme involving the unpaired proton and the 3- state from Ni66 and within shell-model calculations with a Ni56 core using the jj44b residual interaction. The shell model also accounts reasonably well for the other measured electromagnetic transition probabilities.

  3. Reduced electric-octupole transition probabilities, B(E3;O1+ → 31-), for even-even nuclides throughout the periodic table

    International Nuclear Information System (INIS)

    Spear, R.H.


    Adopted values for the excitation energy, E x( 3 1 - ), of the first 3 - state of the even-even nuclei are tabulated. Values of the reduced electric-octupole transition probability, B(E3;O 1 + → 3 1 - ), from the ground state to this state, as determined from Coulomb excitation, lifetime measurements, inelastic electron scattering, deformation parameters β 3 obtained from angular distributions of inelastically scattered nucleons and light ions, and other miscellaneous procedures are listed in separate Tables. Adopted values for B(E3; O 1 + → 3 1 - ) are presented in Table VII, together with the E3 transition strengths, in Weisskopf units, and the product E x( 3 1 - ) x B(E3; O 1 + → 3 1 - - ) expressed as a percentage of the energy-weighted E3 sum-rule strength. An evaluation is made of the reliability of B(E3; O 1 + → 3 1 - ) values deduced from deformation parameters β 3 . The literature has been covered to March 1988

  4. Internal conversion coefficients of high multipole transitions: Experiment and theories

    International Nuclear Information System (INIS)

    Gerl, J.; Vijay Sai, K.; Sainath, M.; Gowrishankar, R.; Venkataramaniah, K.


    A compilation of the available experimental internal conversion coefficients (ICCs), α T , α K , α L , and ratios K/L and K/LM of high multipole (L > 2) transitions for a number of elements in the range 21 ≤ Z ≤ 94 is presented. Our listing of experimental data includes 194 data sets on 110 E3 transitions, 10 data sets on 6 E4 transitions, 11 data sets on 7 E5 transitions, 38 data sets on 21 M3 transitions, and 132 data sets on 68 M4 transitions. Data with less than 10% experimental uncertainty have been selected for comparison with the theoretical values of Hager and Seltzer [R.S. Hager, E.C. Seltzer, Nucl. Data Tables A 4 (1968) 1], Rosel et al. [F. Roesel, H.M. Fries, K. Alder, H.C. Pauli, At. Data Nucl. Data Tables 21 (1978) 91], and BRICC. The relative percentage deviations (%Δ) have been calculated for each of the above theories and the averages (%Δ-bar) are estimated. The Band et al. [I.M. Band, M.B. Trzhaskovskaya, C.W. Nestor Jr., P.O. Tikkanen, S. Raman, At. Data Nucl. Data Tables 81 (2002) 1] tables, using the BRICC interpolation code, are seen to give theoretical ICCs closest to experimental values

  5. Studies of Stable Octupole Deformations in the Radium Region

    CERN Multimedia


    The purpose of the present project is to locate and identify states in the atomic nuclei possessing stable pearshaped octupole deformation. Such states, formally related to the structures known in molecular physics, manifest themselves as families of parity doublets in odd nuclei.\\\\ \\\\ The best possibilities for observing stable octupole deformations are offered in the Ra-region. Both theoretical calculations and experimental indications support such expectations. Such indications are the non-observation of two-phonon octupole vibrational states in the ISOLDE studies of the even-even radium nuclei, and the reversed sign of the decoupling factor of the ground state band in |2|2|5Ra observed in the single-neutron transfer reactions. In order to establish the predicted strong E1 and E3-transitions between the parity doublets in odd nuclei with stable octupole deformations it is proposed to study conversion electrons in odd-mass francium radium and radon isotopes following the @b-decay of francium and astatine. \\...

  6. The 257 MeV 19/2/sup -/ two-phonon octupole state in /sup 147/Gd

    CERN Document Server

    Kleinheinz, P; Kortelahti, M; Piiparinen, M; Styczen, J


    The half-life of the (vf/sub 7/2/*3/sup -/*3/sup -/)/sub 19/2-/ two- phonon octupole states at 2.572 MeV in /sup 147/Gd was measured as T /sub 1/2/=0.37(8) ns, which gives a transition strength of 52(15) WU for the 1525 keV E3 transition to the 0.997 MeV (vf/sub 7/2/*3/sup -/) /sub 13/2+/ one transition to the 0.997 MeV ( nu f/sub 7/2/*3/sup -/) /sub 13/2+/ one phonon excitation. The nu i/sub 13/2/ admixture in the 13/2/sup +/ one-phonon state, as well as the dominant pi h/sub 11/2/d /sub 5//sup -1/2/ component of the /sup 146/Gd 3/sup -/ state give rise to large anharmonicities for the two-phonon excitation. An estimate of the energy shifts based on empirical coupling matrix elements gives 2.66 MeV excitation for the 19/2/sup -/ two-phonon state, in good agreement with the observed energy of that state. (9 refs).

  7. Nuclear structure near the doubly-magic 100Sn

    International Nuclear Information System (INIS)

    Grawe, H.; Hu, Z.; Roeckl, E.; Gorska, M.; Nyberg, J.; Gadea, A.; Angelis, G. de


    The single particle (hole) energies in 100 Sn, as extrapolated by a shell model analysis of the neighbouring nuclei, show a remarkable similarity to those in 36 Ni, one major shell lower. This is borne out in nearly identical I π =2 + excitation energies, implying E(2 + )≅3 MeV in 100 Sn, and a large neutron effective E2 charge ε≥1.6ε. In contrast a small proton polarisation charge δε≤0.3ε is found, pointing to a large isovector charge. Mean field predictions for single particle energies show substantial deviations from the experimental extrapolation. From the experimental two-proton hole spectrum in 98 Cd an improved empirical interaction is extracted for the π(p 1/2 ,g 9/2 ) model space yielding a good description of the N=50 isotones 95 Rh to 98 Cd. In 104 Sn, for the first time in this region, strong E3 transitions with B(E3)≥17 W.u. were identified, indicating E(3 - )≅3 MeV in 100 Sn. New experimental devices, as the Ge-cluster cube and total absorption spectrometers, applied in a pioneering experiment to the β + /EC decay of 97 Ag, have led to a consistent picture of the Gamow-Teller quenching around 100 Sn. The experimental results are discussed in the framework of various shell model approaches by using both empirical and realistic interactions. (orig.)

  8. Influence of laser beam profile on electromagnetically induced absorption

    International Nuclear Information System (INIS)

    Cuk, S. M.; Radonjic, M.; Krmpot, A. J.; Nikolic, S. N.; Grujic, Z. D.; Jelenkovic, B. M.


    We compared, experimentally and theoretically, Hanle electromagnetically induced absorption (EIA) obtained using Gaussian and Π-shaped laser beams 3 mm in diameter. The study was done by measuring the transmission of a laser locked to the F g =2→F e =3 transition at the D 2 line of 87 Rb in a vacuum cell. EIA linewidths obtained for the two laser profiles were significantly different in the range of laser intensities 1-4 mW/cm 2 . EIA with the Π-shaped laser beam has a broad intensity maximum and linewidths larger than those obtained with the Gaussian beam profile. We also studied Hanle EIA by measuring the transmission of selected segments of the entire laser beam by placing a small movable aperture in front of the detector. Waveforms so obtained in Hanle EIA resonances were strongly influenced both by the radial distance of the transmitted segment from the beam center and by the radial profile of the laser beam. We show that outer regions of Gaussian beam, and central regions of the Π-shaped beam generate the narrowest lines. The different behaviors of EIA owing to different beam profiles revealed by both theory and experiment indicate the importance of the radial profile of the laser beam for proper modeling of coherent effects in alkali metal vapors.

  9. Intensity dependence narrowing of electromagnetically induced absorption in a Doppler-broadened medium

    International Nuclear Information System (INIS)

    Dimitrijevic, J.; Arsenovic, D.; Jelenkovic, B. M.


    In this paper, we present a theoretical model for studying the interaction between linearly polarized laser light and near-degenerated Zeeman sublevels for a multiple V-type atomic system of 2 S 1/2 F g =2→ 2 P 3/2 F e =3 transition in 87 Rb. We have calculated the laser absorption in a Hanle configuration, as well as the amplitudes and the widths of electromagnetically induced absorption (EIA) in the range of laser intensities from 0.01 to 40 mW/cm 2 . Our results, showing nonvanishing EIA amplitude, a nonmonotonic increase of the EIA width for the increase of laser intensity, and pronounced shape differences of the Hanle EIA curves at different laser intensities, are in good agreement with recent experimental results. We have found that the EIA behaves differently than the electromagnetically induced transparency (EIT) as a function of the laser intensity. Both the amplitude and width of the EIA have narrow maximums at 1 to 2 mW/cm 2 . We have shown the strong influence of Doppler broadening of atomic transition on Hanle resonances and have suggested the explanation of it

  10. Enhanced E3 Excitations in 144,146Ba and the Evolution of Octupole Collectivity (United States)

    Bucher, B.; Zhu, S.; ANL, LLNL, LBNL, INL, UAM, Rochester, Maryland Collaboration


    Recent Coulomb excitation studies on 144,146Ba using the GRETINA-CHICO2 detection system with post-accelerated CARIBU beams have confirmed the existence of enhanced E3 transitions in these isotopes which are centered in a region that has long been predicted to exhibit stable octupole-deformed shapes. Furthermore, the widely-varying E1 strength observed between these isotopes is well-accounted for by models having octupole-deformed potentials, and the variation has been linked to increased occupancies of specific single-particle orbitals in the reflection-asymmetric potential. This talk will summarize the most recent experimental and theoretical results. In addition, data on octupole-related properties in the surrounding isotopes will be discussed in an attempt to better understand the origin and evolution of octupole collectivity in this mass region. This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357 (ANL), DE-AC02-05CH11231 (LBNL, GRETINA), DOE DE-AC52-07NA27344 (LLNL), DE-AC07-05ID14517 (INL), and MINECO (Spain).

  11. Nuclear structure studies with pions and light and heavy ions. Progress report, June 1, 1981-May 31, 1984

    International Nuclear Information System (INIS)

    Dehnhard, D.


    A large number of experiments were done using pion and proton beams at intermediate energies to investigate different excitation modes of the nucleus. Pions were found to be especially suited to excite magnetic transitions of high multipolarity (M4's). The isospin, or neutron/proton, structure of many transitions could be unraveled and detailed comparisons with the predictions of large-space shell-model calculations were successful in many cases. A few glaring exceptions were found to the general good agreement between theory and experiment. For the collectively enhanced electric quadrupole (E2) and octupole (E3) transitions, effective charge enhancements were needed to fit the pion and proton data. The polarization charges were usually found to be in good agreement with the results of electromagnetic measurements. Studies of the excitation of giant resonances by pion inelastic scattering indicated a large isovector component in the transitions to isoscalar giant resonances. This result, although theoretically unexpected, is supported by comparison of electron and alpha-particle scattering and requires further study. A very recent experiment on pion inelastic scattering from 4 He showed little evidence for isospin mixing in this nucleus, in contrast to the conclusions drawn from (γ,n) and (γ,p) work. A high precision elastic π + scattering experiment on 4 He is underway. The work on heavy-ion elastic scattering was completed and terminated. Two experiments are presently being done at lower energies to supplement the work at intermediate energy

  12. Nuclear structure from N ≅ Z to N > Z - 100Sn, 78Ni, 208Pb

    International Nuclear Information System (INIS)

    Grawe, H.; Gorska, M.; Rejmund, M.; Pfuetzner, M.; Brown, B.A.; Maier, K.H.


    The single particle (hole) energies in 100 Sn, as extrapolated by a shell model analysis of the neighbouring nuclei, show a remarkable similarity to those in 56 Ni, one major shell lower. This is borne out in nearly identical I π =2 + excitation energies, implying E(2 + )≅3 MeV in 100 Sn, and a large neutron effective E2 charge e≥1.6e. In contrast a small proton polarisation charge δe≤0.3e is found, pointing to a large isovector charge. In 104 Sn for the first time in this region strong E3 transitions with B(E3)≥17 Wu were identified, indicating E(3 - )≅3 MeV in 100 Sn. Isomer spectroscopy beyond 68 Ni following fragmentation of a 60.3 A MeV 86 Kr beam has provided first evidence on the neutron polarisation charge and the occupation of the νg 9/2 orbital beyond N=40, which is at variance with shell model calculations using realistic interactions. The N=40 subshell effect seen in E(2 + ) is not borne out in 2n separation energies. On the other hand the νg 9/2 -f 5/2 splitting of single quasiparticle energies in Ni, Fe and Cr isotopes, as deduced from M2 isomers, give no hint for deformation at Z 208 Pb a number of new isomers were observed in the fragmentation of a 1000 A MeV 238 U beam, while 3 - excitations on high spin configurations in and adjacent to 208 Pb were identified in inelastic collisions of 208 Pb+ 208 Pb. E2 and E3 strengths from stretched configurations are compared to model expectations. (orig.)

  13. Probing the collectivity in neutron-rich Cd isotopes via γ-ray spectroscopy

    International Nuclear Information System (INIS)

    Naqvi, Farheen


    The spin and configurational structure of excited states of 127 Cd, 125 Cd and 129 Cd, having two proton and three, five and one neutron holes, respectively in the doubly magic 132 Sn core have been studied. The isomeric states in Cd isotopes were populated in the fragmentation of a 136 Xe beam at an energy of 750 MeV/u on a 9 Be target of 4 g/cm 2 . The experiment was performed at GSI Darmstadt. The neutron-rich Cd isotopes were selected using the Bρ - ΔE - Bρ method at the FRagment Separator (FRS). Event by event identification of fragments in terms of their A (mass) and Z (charge) was provided by the standard FRS detectors. The reaction residues were implanted in a plastic stopper surrounded by 15 Ge cluster detectors from the RISING array to detect the γ decays. In 127 Cd, an isomeric state with a half-life of 17.5(3) μs has been detected. This yrast (19/2) + isomer is proposed to have mixed proton-neutron configurations and to decay by two competing stretched M2 and E3 transitions. Experimental results are compared with the isotone 129 Sn. In 125 Cd, apart from the previously observed (19/2) + isomer, two new metastable states at 3896 keV and 2141 keV have been detected. A half-life of 13.6(2) μs was measured for the (19/2) + isomer, having a decay structure similar to the corresponding isomeric state in 127 Cd. The higher lying isomers have a half-life of 3.1(1) μs and 2.5(15) ns, respectively. Time distributions of delayed γ transitions and γγ-coincidence relations were exploited to construct decay schemes for the two nuclei. Comparison of the experimental data with shell-model calculations is also discussed. The new information provides input for the proton-neutron interaction in nuclei around the doubly magic 132 Sn core. The γ decays of the isomeric states in 129 Cd were not observed experimentally. The reasons for the non-observation of delayed γ rays for 129 Cd are either an isomeric half-life of less than 93 ns based on the experimentally