Search

With the nearly monochromatic, linearly polarized photon beam at the High Intensity γ‐ray source (HIγS) at DFELL photon scattering experiments on 206,207,208pb have been performed. With these experiments Pb(γ,γ′) photon scattering reactions could be used to determine spin and parity quantum numbers and therefore study the v(3p1/2−1‐hole coupling of 207Pb to dipole excitations in 208Pb

A tractable scheme for numerical diagonalization of the Bohr Hamiltonian, based on SU(1,1)×SO(5) algebraic methods, has recently been proposed. The direct product basis obtained from an optimally chosen set of SU(1,1) β wave functions and the SO(5) spherical harmonics ΨvαLM(γ,Ω) provides an exceedingly efficient basis for numerical solution, as compared to conventional diagonalization in a five‐dimensional oscillator basis. In this contribution, the status of the SU(1,1)×SO(5) algebraic collective model is summarized and applications are presented. In particular, the transition from axially symmetric to triaxial structure is explored.

The observation of neutrinoless double beta decay would be proof of the Majorana nature of the neutrino. Half‐lives for these decays are very long (for 76Ge:>1025 y), so background reduction and rejection is the major task for double beta experiments. The GERDA (GERmanium Detector Array) experiment at the Gran Sasso Laboratory of the INFN (LNGS) searches for neutrinoless double beta decay of 76Ge. The isotope 76Ge is an ideal candidate because it can be used as source and detector at the same time. A large remaining contribution to the background arises from the prompt gamma cascade after neutron capture by 76Ge followed by β−‐decay of 77Ge. Since the prompt gamma decay scheme is poorly known, measurements with isotopically enriched Germanium samples were carried out at the PGAA facility at the research reactor FRM II (Munich). With the known prompt gamma spectrum it will be possible to improve the overall veto efficiency of the GERDA experiment.

It is shown that the Mallmann’s energy correlations, introduced a long time ago for the ground state bands of the even‐even nuclei are, in fact, universal. Various bands in all collective nuclei (even‐even, odd‐even, and odd‐odd) obey the same systematics. This unique, universal behaviour indicates the same spin dependence of the energy of the levels and, consequently, a common structure of all collective bands. Based on the second‐order anharmonic vibrator description, parameter‐free recurrence relations between energy ratios are deduced. These relations can be used to predict levels of higher spins in various bands.

At the time neon burning is activated in massive stars, large amounts of 25Mg and 26Mg have been accumulated from the previous evolutionary phases. In particular, at typical temperatures for neon shell burning, the reactions 25Mg(α,n)28Si and 26Mg(α,n)29Si become efficient providing additional neutron fluxes and affecting the nucleosynthesis distribution. Good knowledge of the reaction rates is required to study their effect on nucleosynthesis during neon shell burning conditions (T9≳1.5, where T9 is the temperature in gigakelvin). At the Nuclear Science Laboratory, University of Notre Dame, IN, USA we developed a neutron detector to investigate the 25Mg(α,n)28Si and 26Mg(α,n)29Si reactions as possible neutron sources during neon shell burning. In the present paper we briefly describe the experimental procedures developed to measure those reactions. Finally, we discuss the impact of 25Mg(α,n)28Si and 26Mg(α,n)29Si on the s‐process nucleosynthesis for the barium isotopes.

Spectra of the 9Be(e,e′) reaction have been measured at the S‐DALINAC at an electron energy E0 = 73 MeV and scattering angles of 93° and 141° with high energy resolution up to excitation energies Ex = 8 MeV. The astrophysically relevant 9Be(γ,n) cross sections have been extracted from the (e,e′) data. The resonance parameters of the first 1/2+ state in 9Be have been derived in a one‐level R‐matrix approximation resulting in a resonance energy ER = 1.748(6) MeV and a resonance width ΓR = 274(8) keV These parameters are in mutual agreement with those obtained from the latest real photon experiments but with improved uncertainties.

The energy spectrum and electromagnetic transition properties of the supermultiplet members with two proton fermions can be constructed using the dynamical Uv(6/12)⊗Uπ(6/4) extended supersymmetry. In order to investigate predictions of the two proton fermion—four neutron boson supermultiplet member 198Hg, an experiment with the HORUS cube γ‐ray spectrometer at the Cologne TANDEM accelerator was performed using the 196Pt(α,2n)198Hg reaction. By analyzing γγ coincidence spectra and γγ angular correlations, the required experimental data—level and decay energies, level spins and multipole mixing ratios—could be obtained. For the low‐energy states, the experimental data show good agreement with theory.

Recently, a new signature for quantum phase transitional regions has been discussed. This signature, based on degeneracies of yrast and intrinsic excitations, can distinguish first and second order phase transitions, and is valid not only at or near the analytic critical points described by X(5) and E(5), but along the phase transitional line connecting them as well. In addition, a study of a number of recent analytic solutions to the Bohr Hamiltonian and of the dynamical symmetries of the IBA Hamiltonian has revealed a set of extremely simple and general analytic formulas that describe the energies of 0+ states. For the case of flat‐bottomed geometrical potentials, the formula depends solely on the number of relevant dimensions. For the IBA (large boson number limit) a single formula describes all three dynamical symmetries.

Calculations of the isomer ratio in the nucleus 117In produced by the reactions 114Cd(α,p)117In, 112Cd(6He,p)117In and 110Cd(8He,p)117In are presented. The results of the (α,p)‐reaction are compared with experimental data.

The nuclear structure of neutron‐rich N⩾126 nuclei have been investigated following their production via relativistic projectile fragmentation of a E/A = 1 GeV 238U beam on a Be target. The cocktail of secondary beam products were separated and identified using the GSI FRagment Separator (FRS). The nuclei of interest were implanted in a high‐granularity active stopper detector set‐up consisting of 6 double sided silicon strip detectors. The associated gamma‐ray transitions were detected with the RISING array, consisting of 15 Euroball cluster Ge‐detectors. Time‐correlated gamma decays from individually identified nuclear species have been recorded, allowing the clean identification of isomeric decays.

With the RI Beam Factory at RIKEN being on the cusp to deliver the world’s most intense radioactive ion beams at relativistic energies, a new γ‐ray detection array has been proposed to exploit the new experimental possibilities coming along with it. The material LaBr3 (Ce) possesses an unprecedentedly high intrinsic energy resolution for scintillators of ≈2% at 1.3 MeV and is therefore well suited for high‐resolution in‐beam γ‐ray experiments at relativistic energies. To minimize Doppler effects, the total array will comprise of up to one thousand individual crystals. It is intended to place the array around the secondary target area of the large acceptance fragment separator BigRIPS and use it either in a stand‐alone mode or in addition to a reconfigured DALI2 array. Alternatively, the array will be used in a different configuration for stopped beam, delayed γ‐ray decay experiments.

The Zr isotopes between 90Zr and 96Zr are expected to be spherical based on the almost complete subshell closures at Z = 40 and N = 50, 56. On the other hand, they have low‐lying 3− states and show the characteristics of low frequency octupole oscillation which arise as a superposition of particle‐hole excitations. A 380 MeV 94Zr beam from the tandem accelerator at the Japan Atomic Energy Agency (JAEA) was excited on a self‐supporting natPb target. The gamma‐ray detector array GEMINI‐II was used to detect deexcitation gamma rays. The scattered beam (94Zr) was detected with a position‐sensitive particle detector system. The gamma‐ray intensities were used as an input to the least‐squares search code GOSIA to determine the E3 matrix element of the first 3− excited state of 94Zr. The B(E3;0+→3−) value of 0.21(6) e2b3 in 94Zr has been obtained by Coulomb excitation experiment.

Particle‐triaxial rotor calculations have been performed for the negative parity states in 195Pt and 193Os. The doublet structure of the low‐lying excited states is better described when a Woods‐Saxon potential is used compared to the use of a modified harmonic oscillator potential. The predicted level energies and B(E2) transition strengths are in overall agreement with the experimental data and the U(6/12) results. The ratios of B(E2) values between the states of two doublets agree well with those obtained assuming a pseudospin symmetry. In 193Os, the model calculations can be used for clarification of the spin assignments in cases where they are ambiguous. It is interesting to check them by new precise spin determination.

The decay heat of the fission products plays an important role in predicting the heat‐up of nuclear fuel after reactor shutdown. This form of energy release is calculated as the sum of the energy‐weighted activities of all fission products P(t) = ΣEiλiNi(t), where Ei is the decay energy of nuclide i (gamma and beta component), λi is the decay constant of nuclide i and Ni(t) is the number of nuclide i at cooling time t. Even though the reproduction of the measured decay heat has improved in recent years, there is still a long standing discrepancy at t∼1000 s cooling time for some fuels. A possible explanation for this disagreement can been found in the work of Yoshida et al. [1], who demonstrated that an incomplete knowledge of the β‐decay of some Tc isotopes could be the source of the systematic discrepancy. Motivated by [1], we have recently measured the β‐decay process of some Tc isotopes using a total absorption spectrometer at the IGISOL facility in Jyvaskyla. The results of the measurements are discussed, along with their impact on summation calculations.

Coulomb excitation experiments in inverse kinematics on beams of stable {sup 134,132,130,128,126,124}Xe ions impinging on a carbon target at energies of 82% of the respective Coulomb barriers have been performed. The one-phonon 2{sub 1,ms}{sup +} states have been tracked and identified in {sup 134,132,130,128}Xe from the 2{sub i,ms}{sup +}{yields}2{sub 1}{sup +} M1 strength distributions and from 0{sub 1}{sup +}{yields}2{sub i,ms}{sup +} E2 strength distributions responsible for the one-step Coulomb excitation processes. The evolution of the one-phonon 2{sub 1,ms}{sup +} state within the seven even-even stable Xe isotopes is here presented.

Some challenges faced by nuclear structure physics in the next decade are briefly mentioned. Particularly important are, in experimental nuclear structure physics, the study and understanding of quantum shape phase transitions in mixed Bose‐Fermi systems and in two‐fluid systems, and, in theoretical nuclear structure physics, the development of up‐to‐date theories of collective motion.

In recent years collectivity in the mass region around A = 100 has become the focus of increased interest. The N = 52 isotones were investigated in detail and phonon excitations ‐especially one‐ and two‐phonon mixed‐symmetry states—were identified. In order to investigate how vibrator‐like behavior and states with mixed‐symmetry character evolve with increasing neutron number it is interesting to study the N = 54 isotones. Therefore an experiment to measure the low‐spin excitations of 100Pd was performed at the FN‐Tandem accelerator with the HORUS cube spectrometer. Besides the determination of excitation and transition energies and branching ratios, spins and multipole mixing ratios resulted from the γγ angular correlation analysis. The newly gained data were compared with predictions from theory both from collective models and from shell model.

Proton capture reactions in the CNO cycles define the energy production, nucleosynthesis and timescale of stellar hydrogen burning in massive stars. This paper investigates present uncertainties and inconsistencies in the low energy cross section and reaction rates of critical CNO reactions. The results indicate that new measurements are necessary to reduce the present uncertainties in the reaction rates of the CNO process.

The 72Ge(n,α)69mZn, 74Ge(n,α)71mZn, 76Ge(n,2n)75g+mGe reaction cross sections have been measured from 9.6 to 11.4 MeV and studied, along with data from literature, within the frame of the statistical model using the code EMPIRE‐II.

Neutron capture cross section data on Am isotopes were measured using the Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory. The neutron capture cross section was determined for 241Am for neutron energies between thermal and 320 keV. Preliminary results were also obtained for 243Am for neutron energies between 10 eV and 250 keV. The results on concurrent neutron‐induced fission and neutron‐capture measurements on 242mAm will be presented where the fission events were actively triggered during the experiments. In these experiments, a Parallel‐Plate Avalanche Counter (PPAC) detector that surrounds the target located in the center of the DANCE array was used as a fission‐tagging detector to separate (n,γ) events from (n,f) events. The first direct observation of neutron capture on 242mAm in the resonance region in between 2 and 9 eV of the neutron energy was obtained.

The comparisons of different phenomenological methods for calculation of vibrational and rotational enhancement factors of nuclear level density in spherical and deformed nuclei are performed. A practical method for the calculation of vibrational enhancement factor and level density parameters is recommended. The asymptotic level density parameters and additional energy shifts are obtained for 291 atomic nuclei. The systematics of these parameters are given.

This manuscript discusses recent progress in our understanding of the nucleosynthesis of medium and heavy elements in supernovae. Recent hydrodynamical models of core‐collapse supernovae show that at early times large amounts of proton rich matter is ejected under strong neutrino fluxes. This matter constitutes the site of the vp‐process where antineutrino absorption reactions catalyze the nucleosynthesis of nuclei with A>64. At later times, the ejected matter becomes neutron‐rich and might be the site for the r‐process. The sensitivity of the r‐process to the nuclear physics input is discussed.

In thin film technology, analytical methods for monitoring the deposition of oxide and nitride coatings and the effects of corrosive, laser and ion‐beam treatments have attracted considerable attention. For depth‐profiling the concentrations of light isotopes, resonant nuclear reaction analysis is an excellent non‐destructive ion‐beam analytical tool. We report here on precision measurements of the 278 keV 14N(p,γ) and the 151 keV 18O(p,α) resonances using the high‐resolution proton beam of the Gottingen IONAS accelerator. The deduced resonance energies ER and total widths Γ (in the laboratory system) are ER = 277.60(27) keV and Γ = 1115(33) eV for the 14N(p,γ) resonance, and ER = 150.97(26) keV and Γ = 178(35) eV for the 18O(p,α) resonance. These values are significantly more precise than the ones quoted in the literature.

The framework of relativistic energy density functionals is extended to include correlations related to the restoration of broken symmetries and to fluctuations of collective variables. The generator coordinate method is used to perform configuration mixing of angular‐momentum and particle‐number projected relativistic wave functions. This approach enables a quantitative description of the evolution of shell‐structure, deformation and shape coexistence phenomena in nuclei with soft potential energy surfaces, and singular properties of excitation spectra and transition rates at critical points of quantum shape phase transitions.

Expérience KVI-Groningen; International audience; The beta-decay branching ratio of the GT transition in 21Na to the first excited state in 21Ne has been measured. The value obtained of 4.93(20)% is in agreement with the most recent measurement and with the value adopted so far. This confirms that the branching ratio is not the source of discrepancy in a previous measurement of beta−v correlation coefficient which exhibited a 3sigma difference with respect to the Standard Model prediction.

The most widely used theoretical internal conversion coefficient (ICC) tables are of Hager and Seltzer (HS), Rosel et al. and BRICC (Band et al. tables using BRICC interpolation code). A rigorous comparison of experimental ICCs with various theoretical tabulations is possible only when a large data on experimental ICCs is available at one place. For this reason, a compilation of all the available experimental ICCs, αT, αK, αL of E2 transitions for a number of elements in the range of 24⩽Z⩽94 is presented. Listing of experimental data includes 595 datasets corresponding to 505 E2 transitions in 165 nuclei across the nuclear chart. Data with less than 10% experimental uncertainty have been selected for comparison with the theoretical values of Hager and Seltzer, Rosel et al. and BRICC. The relative percentage deviation (%Δ) have been calculated for each of the above theories and the average (%Δ¯) are estimated. The Band et al. tables, using the BRICC interpolation code are seen to give theoretical ICCs clos...

In order to explain the detailed PDR structure, some new effects must be taken into account, in addition to the effects of the standard RPA or QRPA and phonon coupling. New self—consistent calculations within the Green function method including particle‐phonon coupling have been performed with the Skyrme forces SLy4.

Two‐neutron separation energies, quadrupole moments and mean square charge radii, are evaluated for even‐even Osmium isotopes with 78⩽N⩽114. The calculations are performed in the framework of a microscopic model including the pairing correlations rigorously by means of the FSBCS (Fixed‐Sharp‐BCS) method.

The first triple cluster detector was successfully assembled for the next generation high-resolution gamma-ray spectrometer: the Advanced Gamma Tracking Array AGATA. The core part of the detector consists of three encapsulated, 36-fold segmented, high-purity germanium detectors (HPGe) which are operated in a common cryostat. All 111 energy channels are equipped with cold FETs. They provide best energy resolution of core and segment signals. The observable energy range of the Ge detectors was extended up to 100 MeV by applying a time over threshold technique with the newly developed AGATA preamplifiers. Energy resolution for high energetic {gamma}-rays above 10 MeV is measured to be comparable with values obtained with the standard pulse height technique. Detailed cross-talk investigations were performed in order to improve position dependent pulse shape information. For the Ge detectors and its analog preamplifier circuitry a low cross-talk level was determined which compares well with the expected calculated contributions.

At the new research reactor FRM II in Garching near Munich the beam guide with the highest cold neutron flux is dedicated to Prompt Gamma‐ray Activation Analysis (PGAA) and related neutron capture experiments. We have designed a partially ballistic form of the neutron guide with the aim of concentrating the cold neutrons at the target position of the PGAA experiment. The cold neutron flux with a mean energy of only 1.83 meV was measured about 10.5 cm far from the second exit window and reached intensity of 1.7×1010 n/cm2 s at a 2 mm×2 mm gold foil. The PGAA installation is now prepared for three different kinds of measurements—standard PGAA, Neutron Tomography of small samples and position sensitive PGAA, or PGAI for short. We have also measured γγ coincidences in 77Ge. In this paper, we want to introduce the PGAA facility, show the diversity of the recently performed experiments and discuss further possibilities.

The lifetime of the 120Te first‐excited 2+ state is measured using the recoil distance Doppler shift (RDDS) method after population by inverse‐kinematics Coulomb excitation. The resulting mean lifetime of 10.4(2) ps provides a factor of ten improvement in precision relative to the previously accepted value. A number of necessary corrections are discussed stemming from relativistic effects due to large recoil velocities.

The recently measured low‐energy spectra of the N = 80 isotones 134Xe, 136Ba and 138Ce have been investigated in the quasiparticle‐phonon model. The energies and transition strengths are well reproduced. While the observed selection rules reflect the neutron‐proton symmetry and phonon content of the excited states involved in the transitions, the splitting of the M1 strength in 138Ce is shown to be linked to a subtle interplay between pairing and single particle levels across the proton subshell closure.

Neutron transfer (d,p) reaction studies on the N = 50 isotones, 82Ge and 84Se, and A≈130 nuclei, 130,132Sn and 134Te, have been measured. Direct neutron capture cross sections for 82Ge and 84Se (n,γ) have been calculated and are combined with Hauser‐Feshbach expectations to estimate total (n,γ) cross sections. The A≈130 studies used an early implementation of the ORRUBA array of position‐sensitive silicon strip detectors for reaction proton measurements. Preliminary excitation energy and angular distribution results from the A≈130 measurements are reported.

The radiative thermal neutron capture cross section of the astrophysically important 22Ne nucleus has been measured at the guided cold neutron beam of the Budapest Research Reactor. High‐pressure gas‐bottles filled with mixtures of enriched 22Ne and CH4 were used. The cross section was determined by means of the comparator method, and an improved decay‐scheme obtained in this work. The new value for the thermal neutron cross section is 52.7±0.7 mb, 18% larger than the accepted value. The influence of the new cross section on the astrophysical reaction rate is under investigation.

Nucleosynthesis processes involve reactions on several thousand nuclei, both close to and far off stability. The preparation of reaction rates to be used in astrophysical investigations requires experimental and theoretical input. In this context, two interesting aspects are discussed: (i) the relevant gamma transition energies in astrophysical capture reactions, and (ii) the newly discovered Coulomb suppression of the stellar enhancement factor. The latter makes a number of reactions with negative Q value more favorable for experimental investigation than their inverse reactions, contrary to common belief., Comment: 5 pages, 5 figures, to appear in the proceedings of CGS 13 (Int. Conf. Capture Gamma Ray Spectroscopy and Related Topics)

To measure the form factor of isospin polarized one‐quadrupole phonon states of 92Zr at the Z = 40 proton subshell closure and to compare it to the momentum‐transfer dependence of the form factors for the one‐quadrupole phonon states predicted by the Quasiparticle Phonon Model, the 2+ states of 92Zr have been investigated with an electron scattering experiment at the S—DALINAC. The relative E2 excitation strength to off‐yrast 22+ state was also extracted in a model‐independent systematic procedure. A comparison with the data on 94Mo and previous spectroscopic information on MSSs of 92Zr will be given.To measure the form factor of isospin polarized one‐quadrupole phonon states of 92Zr at the Z = 40 proton subshell closure and to compare it to the momentum‐transfer dependence of the form factors for the one‐quadrupole phonon states predicted by the Quasiparticle Phonon Model, the 2+ states of 92Zr have been investigated with an electron scattering experiment at the S—DALINAC. The relative E2 excitation strength to off‐yrast 22+ state was also extracted in a model‐independent systematic procedure. A comparison with the data on 94Mo and previous spectroscopic information on MSSs of 92Zr will be given.

We report on an experiment using Coulomb excitation in inverse kinematics in combination with the plunger technique for measuring lifetimes of excited states of the projectiles. Aside from the investigation of E(5) features in 128Xe, the aim was to explore the special features of such experiments which are also suited to be used with radioactive beams. The measurement was performed at the JYFL with the Koln coincidence plunger device and the JUROGAM spectrometer using a 128Xe beam impinging on a natFe target at a beam energy of 525 MeV. Recoils were detected by means of 32 solar cells placed at extreme forward angles. Particle‐gated γ‐singles and γγ‐coincidences were measured at different target‐degrader distances. Details of the experiment and first results are presented.

We present recent investigations on dipole and quadrupole excitations in spherical skin nuclei, particular exploring their connection to the thickness of the neutron skin. Our theoretical method relies on density functional theory, which provides us with a proper link between nuclear many-body theory of the nuclear ground state and its phenomenological description. For the calculation of the nuclear excited states we apply QPM theory. A new quadrupole mode related to pygmy quadrupole resonance (PQR) in tin isotopes is suggested., Comment: Conference proceedings of the Thirteenth International Symposium on Capture Gamma-Ray Spectroscopy and Related Topics, Cologne (Germany) 2008, to be published by AIP

The spin cut‐off parameter σ has been determined for experimental low‐excitation energy spin distributions of 310 nuclei between 18F and 251Cf (more than 8000 levels with their spin). The results indicate a weak dependence on the mass number, σ2∼A0.30, and a strong even‐odd spin staggering in the even‐even nuclei.

Multi‐step cascades from the 62Ni(ncold,γ) 63Ni reaction were studied via a γ‐ray spectroscopy method. With a γ‐ray detector array multiple γ‐ray coincident events were accumulated. By selecting full cascade events from the capture state to the ground state, we have developed a new computer‐based level construction method and it is applied to excited level assignment in 63Ni.

The in‐pile positron source of NEPOMUC at the neutron source Heinz Maier‐Leibnitz (FRM II) provides at the experimental site an intense beam of monoenergetic positrons with selectable energy between 15 eV and 3 keV. The principle of the source is based on neutron capture gamma rays produced by cadmium in a beam tube tip close to the reactor core. The gamma ray absorption in platinum produces positrons which are moderated and formed to the beam. An unprecedented beam intensity of 9.108 e+/s is achieved (1 keV). The performance and applications of the facility are presented.

Rational relations in values of stable intervals in near‐magic nuclei with Z = 26–29 confirm the presence of tuning effect in nuclear data.

The cross sections of 113In(α,γ)117Sb and 113In(α,n)116Sb reactions have been measured using the activation method. The experiments were carried out at the ATOMKI cyclotron accelerator in the center of mass energy range from 8.7 to 13.7 MeV. Astrophysical S‐factors have been calculated, and preliminary results are compared with statistical model predictions.

Although an important effort has been devoted in the last decades to measure reaction cross sections of interest in astrophysics, most nuclear astrophysics applications still require the use of theoretical predictions to estimate experimentally unknown rates. The nuclear ingredients to the reaction model should preferably be estimated from microscopic or semi‐microscopic global predictions based on sound and reliable nuclear models which, in turn, can compete with more phenomenological highly‐parametrized models in the reproduction of experimental data. The latest developments made in deriving the nuclear inputs of relevance in astrophysics applications are reviewed. They mainly concern nuclear structure properties, nuclear level densities, optical potentials.New developments to improve the predictions of radiative neutron capture rates are also discussed. They include the recent improvements made to the TALYS reaction code and the analysis of the pre‐equilibrium contribution. The direct reaction mechanis...

A method by Peres is used to draw spectra of the geometric collective model and the interacting boson model as lattices in the plane of energy versus an arbitrary observable average (or dispersion). Ordered (disordered) lattices are signatures of regular (chaotic) dynamics on both quantum and classical levels. The method enables one to disclose important features of the system.

It is shown that the assumption of a common mass coefficient for the three basic excitation modes contradicts in the case of the well deformed nuclei and for the usual one parameter quadrupole operator the experimental data on the energies and the E2 transition probabilities. It is shown also that it is possible to perform a transformation of the collective coordinates in such a way as to obtain the Hamiltonian with one common mass coefficient only, however, with the modified E2 transition operator with three parameters and the potential energy.

This paper presents a summary of the latest results from experiments performed at the Oslo Cyclotron. The Oslo group has developed a technique to extract simultaneously the level density and radiative strength function from primary γ‐ray spectra. A small (pygmy) resonance in the radiative strength function has been observed at around 3 MeV in several deformed rare earth nuclei. This resonance is shown to be of M1 character and the origin is thought to be the scissors mode. This resonance vanishes for the spherical Sm nuclei, as expected, since the scissors mode is dependent on deformation. Experiments performed in Oslo found the resonance in Dy isotopes to be twice as wide as the width extracted in an indirect way by comparing simulations with two‐step cascade spectra from neutron capture experiments. In 116,117Sn an increase in the slope of the radiative strength function around Eγ = 4.5 MeV indicates the onset of resonance‐like structures in both nuclei, resulting in a significant enhancement of the rad...