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The first International Conference on NUclear, STructure, Astrophysics and Reactions (NUSTAR'05) was hosted at the University of Surrey, Guildford, UK during 5–8 January 2005. It would be fair to say that when the dates and location for this conference were originally suggested, a number of senior colleagues predicted that 'no one will want to come to England in January'. Luckily, this advice was respectfully ignored and in the final analysis the meeting attracted more than 200 delegates from over 30 different countries. The scientists who braved the English winter to come and hear the latest results in low-energy nuclear physics were also treated to a few examples of peculiarly British culture, including a night out at a pantomime and a banquet held in an English vineyard.

The conference was packed with new and exciting physics. The final tally sheet shows 51 oral presentations in 13 plenary sessions, with 30 additional talks in four more parallel sessions. These were complemented by an astonishing 61 poster presentations of the very highest quality. The original intention of the Organizing Committee was to hold a meeting to bring together the three major strands of low-energy nuclear physics research, namely nuclear structure and reaction physics, and their applications to pertinent questions of astrophysical nucleosynthesis. These aims were in no small part stimulated by the recent explosion of relevant experimental data, particularly with respect to the spectroscopy of exotic nuclei. Many such systems are only now available for detailed study following experiments at the first wave of radioactive-beam facilities such as the NSCL at Michigan State University, GANIL, GSI, RIKEN, TRIUMF, Lanzhou, Oak Ridge, Texas A&M, and CERN-ISOLDE. Data from each of these labs were presented at the conference, attacking fundamental physics questions including: (i) nuclear shell evolution and `melting' for magic numbers at N = 20,28,50 and 82 (prompting the question 'is no magic number safe?!'); (ii) the use of β^- and isomeric decays to provide the first spectroscopic studies in very neutron-rich nuclei; (iii) mass measurements in nuclei far from stability (which are vital input for explosive nuclear astrophysics reaction rate calculations); and (iv) new forms of (two-proton) radioactivity.

These RIB-based studies were complemented by new insights arising from a dazzling array of high-precision experiments performed at stable-beam centres including Argonne National Laboratory, the University of Jyväskylä, WNSL-Yale University, IKP-Köln, INFN-Legnaro, University of Sao Paolo, iThemba-Labs Cape Town, the University of Kentucky, Gran Sasso, TUNL in North Carolina and Florida State University. Data taken at each of these facilities were also presented at the conference, allowing important studies to address questions on: (i) the stability and structure of trans-Fermium nuclei; (ii) shape competition/coexistence in near-proton-drip-line systems; (iii) the nature and density of 0⁺ states; (iv) the potential for new descriptions of transitional nuclei in terms of critical point `phase transitions'; (v) the validity of isospin symmetry in N ∼ Z nuclei; (vi) the physics of the nucleus at the very highest spins; and (vii) very low background astrophysical cross-section measurements for hydrogen burning reactions. Of course, such facilities cannot be adequately exploited without the parallel development of the high-precision instrumentation required to make such measurements and the conference delegates were treated to a glimpse of tomorrow's potential discoveries using instruments such as TIGRESS, AGATA, GRETA, TIARA, GREAT and PRISMA.

The theoretical aspects of the subject were also very well represented with 16 different oral contributions on a wide variety of theoretical aspects, including topics such as sub-barrier fusion, the preponderance of 0⁺ ground states, mean-field and beyond mean-field approaches, collective motion, overlap functions, S-factors for astrophysics, cluster structure, high-spin evolution and wobbling, level densities, giant resonances, and nuclear reaction mechanism descriptions.

With the huge possibilities on the horizon associated with the likes of the RIA, GSI/FAIR, SPIRAL2 and ISAC-2 projects, our subject is in excellent shape and ready to attack the fundamental questions of tomorrow. Mark Riley of Florida State University stated unashamedly in his talk that now is 'the golden era of nuclear physics'. With so many exciting opportunities and physics boundaries to be pushed, we fully agree with this sentiment and conclude that perhaps spending four days in the rain in Surrey in January was not too bad a way to start the International Year of Physics.

It is fitting to finish this short preface by noting the passing in recent months of two giants of the international nuclear physics community, who both served on the conference Organizing Committees, namely Professor Dave Warner from Daresbury (who was a member of the National Organizing Committee) and Professor Gregers Hansen of Michigan State University (who was on the International Advisory Committee). These two distinguished scientists, great ambassadors for nuclear science and true gentlemen, will be sadly missed. Their careers were both excellent examples to the NUSTARs of the future.

We are grateful to the Institute of Physics for financial support for this meeting.

David Warner died on 9 June 2005 leaving a gaping hole in the lives of his family, friends and colleagues and in the nuclear physics community world-wide. A warm, friendly and helpful man, he will be sorely missed, not just by all the individuals close to him but in his role as a nuclear physicist. Dave, as he was generally known, was born in Philadelphia, and lived in the USA until he moved with his mother to Bournemouth in England at the tender age of seven. He was a national of both the UK and the USA and embodied many of the best characteristics of the citizens of both countries.

On leaving school he moved to the University of East Anglia where he graduated with a 1st Class Honours degree in physics. His graduate studies on nuclear orientation applied to experimental nuclear physics were undertaken at Sussex University under the supervision of the late Dennis Hamilton. It was here that he began to lay the foundations of his knowledge of nuclear physics, no doubt influenced by the presence in the Sussex physics department at that time of Professor J P Elliott and his theoretical colleagues. Given this starting point, it should be no surprise to us that he had an excellent knowledge and understanding of the theories of nuclear structure. It was easy to understand why many people asked if he was a theorist or an experimenter. He did not see it as a very meaningful question himself and was in no doubt about the fact that he was an experimenter. It did not stop him making many meaningful contributions to our understanding of nuclear models.

Following his PhD, he took up a position at Institut Laue-Langevin, Grenoble, in 1975 at a time when the reactor centre there was the world-wide focus of nuclear structure studies with slow-neutron-induced reactions. Simultaneously Arima and Iachello introduced the idea of dynamical symmetries into nuclear physics in the form of the Interacting Boson Model (IBM).

In collaboration with Hans Boerner, Klaus Schreckenbach, Walter Davidson and others, he exploited to great advantage the high resolution and sensitivity of the curved-crystal gamma-ray and double-focusing beta spectrometers, with their in-pile targets. He was quick to see the potential of the IBM to give a convincing explanation of the regularities in nuclear structure that their experiments were turning up. It was at ILL that he encountered Rick Casten, then at Brookhaven National Laboratory. This was the start of a long-standing and highly fruitful collaboration. Casten enticed him to Brookhaven and, much to his surprise, the move to the USA did not even mean much in the way of bureaucracy. Unknown to him, US law had changed and his application for a visa was met with the query 'Why are you asking for a visa? You are an American citizen.'

Dave's stay at Brookhaven from 1979 to 1986 was extremely productive in terms of physics and very happy in family terms with the arrival of daughter Jenny and son Steven. To some extent the family seemed to enjoy what one might see as an extended holiday, an atmosphere they recreated on later return visits, first to Brookhaven and later to Yale when Casten moved there. At work he and Casten were excellent foils for each other. Casten is well known for his translation of theoretical ideas into the kind of pictures that other physicists can understand. Dave kept their feet on the ground and together they turned the abstract algebra of the IBM into a readily understood and easily used tool for interpreting the results of nuclear spectroscopy. At the same time, he continued to exploit slow neutrons as an experimental tool but now at the Brookhaven High Flux Beam Reactor.

Proofs of the existence of some of the dynamical symmetries predicted by the IBM, of the applicability of the model to deformed nuclei and some of the earliest evidence for Bose–Fermi symmetries in nuclei flowed from their efforts. Dave's theoretical acumen was also demonstrated by their development of the revised approach to the IBM, called the Consistent Q formalism, which has now become the standard approach to IBM calculations. My own collaboration with him had started at ILL and continued at Brookhaven with joint supervision of Alison Bruce, a Manchester student studying neutron capture at the HFBR. He remained in loco parentis for both Alison and her contemporary as a student at Brookhaven, Ani Aprahamian. How much of his advice rubbed off is hard to tell but I know they both feel he helped and encouraged them to fulfil their potential.

Meanwhile nuclear physics in the UK was flourishing with the success of the Nuclear Structure Facility at Daresbury Laboratory. To my joy, he was attracted back to Daresbury in 1986, where he has spent the last 19 years. Whilst the NSF was still operational, his experimental skills and knowledge of nuclear models contributed much to the stream of excellent work from the facility. For many of us he was the first stop with any query about models and their interpretation. He struck up strong collaborations with experimenters and theorists. With Mike Bentley he helped map out our understanding of Coulomb effects in N = Z nuclei and with Piet Van Isacker he again exploited algebraic models to tackle questions related to np-pairing in these nuclei and how it might reveal itself.

In 1993 the Nuclear Structure Facility at Daresbury was closed without regard to the great success of its experimental programme. Dave, like everyone else in the nuclear physics community, was dismayed at such folly but he set about a new task with energy and vigour, namely creating a support group for the UK nuclear physics community. He put together a group of physicists, engineers, electronics and data acquisition specialists which has been vital to maintaining the UK's nuclear physics diaspora. He played a large part in maintaining the community's morale as well. Wherever we gathered, he always insisted on a chorus of  'Always look on the bright side of life' and most of us who knew him will always associate it with him.

One thing he and I shared was a strong belief that in the long term the UK could only maintain its reputation in nuclear physics and an adequate nuclear skills base if the UK built a world-class facility or was officially part of one. I have lost track of the number of papers we have written, together with others, explaining the great opportunities opened up by our new-found ability to create beams of radioactive nuclei. Always we were told that the science case was unassailable but a new excuse for inaction would be offered. Now the entire UK community is united in wanting the UK to join the future FAIR facility at GSI, Darmstadt, and maintaining a presence at GANIL in France. Again, Dave was in the vanguard, helping to make the case at home and representing CCLRC and the UK on the Science and Technology Committee for the new facility. Throughout a decade and more of such efforts, he kept his own science going at the highest level and sustained the efforts of the UK's university groups in their efforts abroad. He had to sacrifice much of his own time and scientific life to do so.

How can one sum up what one felt about him and how much we will miss him? Not so long ago at a funeral in Guildford, the Rabbi's simple message was 'He was a thoroughly good bloke'. That sounds inadequate at first; not many of us merit such an accolade but Dave did. He leaves all of us, Lin, Jenny and Steve, his friends and colleagues, with warm and happy memories. We shall miss him.

The ground states of all even–even nuclei have angular momentum equal to zero, I = 0, and positive parity, π = +. This feature was believed to be a consequence of the attractive short-range interaction between nucleons. However, a predominance of I^π = 0⁺ ground states was discovered by Johnson, Bertsch and Dean in 1998 using the two-body random ensemble. Since then many efforts have been devoted to understanding and solving this problem by many authors from a lot of view points. Still, the underlying physical origin of the I^π = 0⁺ dominance has not been fully understood. In this paper, we show our recent progress in understanding the 0⁺ dominance of many body systems. Some findings related to the I^π = 0⁺ dominance are also discussed.

Multiphonon excitations in a number of nearly spherical nuclei have been investigated with the (n,n'γ) reaction. Quadrupole three-phonon quintets and candidates for members of the four-phonon octets have been identified in the Cd region. In addition, complete quadrupole–octupole quintets have been characterized in this region, and mixed-symmetry states in vibrational nuclei are now well known. Our best examples of two-phonon octupole states have also emerged in spherical nuclei, such as ²⁰⁸Pb.

The puzzling nature of 0⁺ excitations, especially in transitional and deformed nuclei, has attracted new attention. Following a recent experiment studying ¹⁵⁸Gd, we investigated 15 additional nuclei in and near the rare earth region. Our aim was to map out the energies of as many 0⁺ states as possible. A series of (p, t) experiments was performed at the Q3D magnetic spectrograph at the University of Munich MP tandem accelerator laboratory. These reactions are particularly sensitive to 0⁺ states. Outgoing tritons were recorded at various lab angles, and their relative cross sections are compared to those calculated using the distorted wave Born approximation (DWBA). The L = 0 angular distribution is easily discerned. New 0⁺ states are found in each of these nuclei, and their systematics are discussed.

Proton elastic scattering, proton inelastic scattering, proton transfer reactions and the (d, p) neutron transfer reaction have been measured in inverse kinematics with radioactive ion beams at the HRIBF to determine the properties of nuclear excited states that are important in stellar explosions. The experimental techniques and some initial results are briefly summarized.

Few-body methods provide very useful tools to solve different problems important for nuclear astrophysics. Some of them are discussed below.

Several cross-section measurements of proton as well as α-particle capture reactions in the Se–Sb region have been carried out at sub-Coulomb energies with the aim to obtain global input parameters for Hauser–Feshbach (HF) calculations. Some of the results are compared with HF calculations using various optical model potentials and nuclear level densities.

Ultra-fast time-delayed techniques have been recently applied in a number of studies where exotic nuclei were identified using advanced selection techniques. These include large Compton-suppressed Ge arrays, in-flight separators or recoil separators. Some of the new results are discussed in this presentation. Besides the results for ³²Mg and ⁹⁶Pd, they include the first determination of the half-life of the 8⁺ state in ⁸⁰Ge, T_1/2 = 2.95(6) ns, and significantly more precise results for ⁵¹Mn (3680 keV level) and ⁴⁸V (421 keV level), T_1/2 = 1760(40) ps and T_1/2 ⩽ 135 ps, respectively. Development of new scintillators will steadily improve precision and sensitivity of future measurements.

Based on the energy spectra and relative transition probabilities ^176,178,180Os turned out to be very promising candidates for testing the features of the critical point symmetry X(5). In order to also test absolute transition probabilities predicted in the framework of the X(5) symmetry lifetime measurements were performed at the Cologne FN tandem accelerator. The lifetimes of the first 2⁺ states in ^176,178,180Os were measured using electronic timing and in the case of ¹⁷⁸Os with the recoil distance Doppler shift (RDDS) technique using an ¹⁶O-induced fusion evaporation reaction. In addition, a coincidence RDDS measurement was performed at the Laboratori Nazionali di Legnaro with the GASP spectrometer using the ¹⁵⁴Sm(²⁹Si,5n)¹⁷⁸Os reaction. The deduced transition quadrupole moments agree well with the X(5) predictions, thus further supporting an X(5) structure for ¹⁷⁸Os. The experimental data for ¹⁷⁸Os are compared to calculations in the framework of the interaction boson model (IBM) and of the general collective model (GCM).

The magnetic moments of I^π = 2⁺₁ states in even–even A ∼ 100 fission fragments have been measured using the Gammasphere array, using the technique of time-integral perturbed angular correlations. The collective (core) g factors of several odd nuclei have also been determined. The data are interpreted within the context of the interacting boson model (IBA2).

We report on the first measurement of the g factor of the J^π = 9/2⁺ isomeric state in ⁶⁵Ni. (d,p) reactions on enriched ⁶⁴Ni and ⁶²Ni have been used in order to populate and spin orient the J^π = 9/2⁺ isomeric states in ⁶⁵Ni and ⁶³Ni. The hyperfine field of the Ni target, oriented by an external magnetic field, was used in order to obtain a sufficient number of spin precessions within the relatively short life time of the isomers. The g factor obtained, g(^65mNi) = −0.296(3), is in good agreement with the g factors of other 9/2⁺ states in the region and with shell-model calculations.

CLARA is an array of 25 Clover (EUROBALL type) Ge detectors, placed at the target position of the large acceptance magnetic spectrometer PRISMA. Due to the granularity of the CLARA Ge array (100 crystals), the photopeak efficiency (≈3%) and the PRISMA large acceptance (≈80 msr, and 20% Δp/p), the setup is an excellent tool to investigate the structure of neutron-rich nuclei, populated in multinucleon transfer reactions and deep inelastic collisions with stable beams. Since March 2004 the setup is fully operational, and since then several experiments have been performed, with beams delivered by the LNL XTU-Tandem and the ALPI linac. In this contribution the preliminary outcome of the first experiments is shown.

We discuss the problem of subbarrier fusion processes in reactions involving weakly-bound projectiles, in particular with respect to the effect of the strong coupling to break-up channels. Within a simple schematic coupled-channel model we show that the coupling to reaction channels (including continuum break-up channels) seems to predict enhancement of fusion below the barrier (for total fusion and, to a lesser degree, also for complete fusion), when the reaction process is treated within the conventional approach, with proper modifications due to weak-binding nature of halo systems (as for example the long range of formfactors and potentials)

The properties of the yrast and yrare states with the νh_11/2 ⊗ πh_11/2 configuration in the mass A ∼ 130 region are studied by a full microscopic theoretical framework of the pair-truncated shell model. This approach for energy levels and electromagnetic transition rates in ¹³⁴La gives good agreement with experiment. The analysis of the wavefunctions reveals new band structure, which results from chopsticks configurations of two angular momenta of the unpaired neutron and the unpaired proton, weakly coupled with the quadrupole collective excitations of the even–even core.

The structure of excited states of ¹⁷C has been studied using the three-neutron transfer reaction ¹⁴C(¹²C, ⁹C)¹⁷C at 231 MeV. Thirteen states above the neutron threshold up to 16.3 MeV excitation energy are observed. The large negative reaction Q-value of Q₀ = −46.930 MeV leads to a strong mismatch between entrance and exit channels. In this case the population of stretched configurations is strongly favoured. The lowest-lying 9/2⁺ state could be identified at 3.10 MeV, in excellent agreement with shell model calculations. Further tentative assignments could be given for several other states. A striking agreement is observed between excitation energies of ¹⁷C and those states of ¹⁶C populated in the ¹³C(¹²C, ⁹C)¹⁶C reaction, when the level schemes of both nuclei are aligned along the 9/2⁺ state at 3.10 MeV in ¹⁷C and the [9/2⁺ ⊗ 1/2⁻]5⁻ state at 8.92 MeV in ¹⁶C. Deviations between E_x(¹⁷C) and the difference E_x(¹⁶C) − 5.82 stay within the range of +0.14/ −0.17 MeV for ten pairs of states of these isotopes.

The low-lying levels in ^59,60Cr have been populated with ^13,14C(⁴⁸Ca, 2p) reactions using a beam energy of 130 MeV. Prompt electromagnetic radiation was detected using the Gammasphere array, in coincidence with recoiling ions measured with the Fragment Mass Analyzer. The residues were selected and identified on the basis of charge-to-mass ratio, energy-loss and time-of-flight measurements. Preliminary results for ⁶⁰Cr, when compared to lighter even-even isotopes, indicate a softness in shape which increases with neutron number. The low-lying structure of ⁵⁹Cr is clearly inconsistent with the results of a spherical shell-model calculation and requires the inclusion of the νg_9/2 orbital. The sequence of states can be understood within the Nilsson model assuming a moderate oblate ground-state deformation. This is in contrast to lighter odd-Cr nuclei where there is evidence for prolate deformation after excitation of g_9/2 neutrons.

The current experimental status of double beta decay searches is reviewed.

Measurements of beta decay reduced transition probabilities are particularly relevant in nuclei far from the stability line. It has been demonstrated that a proper measurement of this quantity requires the use of the total absorption technique, which has become a reliable tool in recent years, thanks to the increased efficiency of the associated spectrometers and the development of new analysis techniques. In this paper, we present a brief history of the past and present use of these detectors and how they might be developed in the future.

Recent theoretical and experimental work focusing on nuclei in spherical–deformed transition regions has sparked considerable interest in phase transitional nuclei. A review of searches and experimental results on critical point nuclei in the A = 130 and A = 150 regions is presented.

High-resolution γ-ray spectroscopy is essential to fully exploit the unique, high-quality beams available at the next generation of radioactive ion beam facilities such as the TRIUMF isotope separator and accelerator (ISAC). The 8π spectrometer, which consists of 20 Compton-suppressed HPGe detectors, has recently been reconfigured for a vigorous research programme in weak interaction and nuclear structure physics. With the addition of a variety of ancillary detectors it has become the world's most powerful device dedicated to β-decay studies. This paper provides a brief overview of the apparatus and highlights from recent experiments.

FURIOS, the Fast Universal laser IOn Source, is under development at the IGISOL (Ion Guide Isotope Separator On-Line) mass separator facility in Jyväskylä, Finland. This new laser ion source will combine a state-of-the-art solid state laser system together with a dye laser system, for the selective and efficient production of exotic radioactive species without compromising the universality and fast release inherent in the IGISOL system. The motivation for, and development of, this ion source is discussed in relation to the programme of research ongoing at this mass separator facility.

Proton decay has been transformed in recent years from an exotic phenomenon into a powerful spectroscopic tool. The frontiers of experimental and theoretical proton-decay studies will be reviewed. Different aspects of proton decay will be illustrated with recent results on the deformed proton emitter ¹³⁵Tb, the odd–odd deformed proton emitter ¹³⁰Eu, the complex fine structure in the odd–odd ¹⁴⁶Tm nucleus and on excited states in the transitional proton emitter ¹⁴⁵Tm.

After ⁴⁵Fe, another precursor nucleus for two-proton radioactivity has been observed: ⁵⁴Zn. It has been produced and identified in an experiment performed at the GANIL/LISE3 facility. In addition to this first observation of ⁵⁴Zn and its two-proton decay, the experiment allowed for a confirmation of previous results on the two-proton decay of ⁴⁵Fe and of the existence of ⁴⁸Ni, and gave first indications about its decay.

By taking advantage of the high efficiency of the Coulomb dissociation method, we studied the stellar ²²Mg(p, γ)²³Al reaction. The radiative width Γ_γ of the first excited state in ²³Al was determined by measuring the intermediate-energy ²³Al → ²²Mg + p breakup process with a lead target.

We investigate the shape mixing in ⁶⁸Se using the adiabatic self-consistent collective method. This nucleus ⁶⁸Se is known to show oblate–prolate shape coexistence at low angular momentum. We calculate the collective path between the oblate and prolate minima and show how the collective behaviour of the system changes with angular momentum.

An experiment utilizing a double fragmentation reaction was performed to study isobaric analogue states in A ∼ 50 nuclei approaching the proton drip-line. γ-ray spectroscopy will be used to identify excited states in the neutron-deficient nuclei produced in the second fragmentation reaction. Excited state level schemes will be obtained, through comparison with states in their well-known mirror partners, along with information on Coulomb effects through measurements of the Coulomb energy differences between isobaric analogue excited states. The validity of isospin symmetry for nuclei approaching the proton drip-line can also be investigated and the information gained will aid in testing and improving fp shell model calculations. The analysis of the collected data is at a preliminary stage and current status of this work is reported.

Nuclear structure data are of crucial importance in order to address important astrophysical problems such as the origin of chemical elements, the inner working of our sun and the evolution of stars. We demonstrate this by investigating the ground-state structure of ⁸B and ⁷Be nuclei within the Skyrme Hartree–Fock framework and by calculating the overlap integral of ⁸B and ⁷Be wavefunctions. The latter is used to calculate the astrophysical S factor (S₁₇) for the solar fusion reaction ⁷Be(p, γ)⁸B.

The ¹⁴N(p,γ)¹⁵O reaction has been investigated by the LUNA experiment at the National Laboratory of Gran Sasso (LNGS). This study has been performed with two different setups. The first one, suitable for the detection of γ-rays produced by single transitions, has been based on an HPGe detector and a solid target. In a second phase, we used a BGO summing crystal as a detector and a windowless gas target. The BGO high detection efficiency and the target purity allowed us to measure the total S factor down to E_cm = 70 keV.

We employed the Skyrme–Hartree–Fock + BCS model to investigate the density distributions of even–even superheavy nuclei around the predicted magic numbers of Z = 114, 120, 126 and N = 172, 184. The central depressions in densities are shown in the heaviest nuclei with Z ⩽ 120 and N ⩽ 178, which is due to high-j orbits occupied. However, densities become flatter when deformations occur. The superheavy nuclei with N = 180–188 and Z = 126 have no central depressions, due to that low-j orbits become occupied. Shell closures in the superheavy mass region are isospin dependent.

High-spin band structures in ¹⁸⁴Au have been re-investigated using the multidetector array of GASP following the ¹⁴⁹Sm(²⁹Si, 4nγ)¹⁸⁴Au reaction. Four previously observed bands built on prolate configurations have been extended significantly up to high spins and two weakly populated bands are newly identified. Structure properties of these bands are briefly discussed.

The grounds on which the nuclear pseudospin symmetry (PSS) is supposed to be based are analysed within the relativistic mean-field framework. A comparative analysis of the mechanisms responsible for the breaking of the spin and pseudospin symmetries, which clarifies the different nature of these symmetries, is made. A non-relativistic explanation of the PSS, based on the effect of the spin–orbit interaction, is also sketched.

The potential energy surface of the ²⁵²Cf nucleus has been computed within the Hartree–Fock–Bogolubov theory with the D1S Gogny force. The shape evolution of the nucleus during the fission process has been studied with constraints on quadrupole, octupole and hexadecapole moments. The calculation was performed up to the scission configuration.

Lifetimes of states in the magnetic band in ¹⁹³Pb have been measured with the recoil-distance Doppler-shift (RDDS) method. This band is built on the I^π = 29/2⁻ isomer (E_ex = 2584 keV, T_1/2 = 9.4 ns). High-spin states in ¹⁹³Pb were populated in the ¹⁷⁰Er (²⁸Si, 5n) reaction at 149 MeV. The nuclear γ-decay was detected with the GASP spectrometer in combination with the Köln plunger device. These results provide for the first time a complete set of experimental observables for such an excitation in atomic nuclei.

Lifetimes for decays linking near-yrast states in ¹⁰⁷Cd have been measured using the recoil distance method (RDM). The nucleus of interest was populated via the ⁹⁸Mo(¹²C,3n)¹⁰⁷Cd fusion–evaporation reaction at an incident beam energy of 60 MeV. From the measured lifetimes, transition probabilities have been deduced and compared with the theoretical B(E2) values for limiting cases of harmonic vibrational and axially deformed rotational systems. Our initial results suggest a rotor-like behaviour for the structure based on the unnatural-parity, h_11/2 orbital in ¹⁰⁷Cd, providing further evidence for the role of this 'shape-polarizing' orbital in stabilizing the nuclear deformation in the A ∼ 100 transitional region.

The non-adiabatic quasi-particle approach for proton radioactivity from deformed drip-line nuclei is discussed. All experimental data available on decay from ground and isomeric states, and fine structure of odd–even and odd–odd nuclei, are consistently interpreted without free parameters, by this theoretical approach.

Measuring the neutron-induced fission cross-sections of short-lived nuclei represents an experimental challenge due to target activity and the low intensity of neutron beams. One way to alleviate the problems inherent in the direct measurement is to use the surrogate method, where one measures the decay probability of the same compound nucleus formed using a charged beam and a stable target. The decay probability of the compound nucleus is then used to estimate the neutron-induced cross-section. As an extension to the surrogate method, we introduce a new method of reporting the fission probabilities of two compound nuclei as a ratio, which has the advantage of removing most of the systematic uncertainties. The ratio method was checked in a known case, the ²³⁶U(n, f)/²³⁸U(n, f) cross-section ratio, which turned out to be the same as the probability ratio of P(²³⁶U(d, pf))/P(²³⁸U(d, pf)). As an application, the ²³⁷U(n, f)/²³⁵U(n, f) cross-section ratio was inferred, on the basis of the measured P(²³⁸U(d, d'f))/P(²³⁶U(d, d'f)) probability ratio.

The odd–odd ⁵⁸Co nucleus has been studied with the ⁵¹V(¹⁰B, p2n) reaction at 33 MeV and 36 MeV incident energy using the γ-spectrometer Saci-Pererê. Excited states up to 8.0 MeV and spin up to 11⁺ have been observed. DSAM lifetimes for 13 excited states were measured. The results are compared to shell model calculations using the GXPF1 effective interaction, developed for use in the fp shell.

Inelastic scattering of loosely bound nuclei by Coulomb interaction at intermediate energies (400–600 MeV/nucleon) has been utilized as a spectroscopic tool for exotic nuclei. The observed electromagnetic dipole (E1) strength above the one neutron threshold of neutron-rich C, Be, B and O isotopes can be explained by a non-resonant transition of a neutron into the continuum. The shape of these strength distributions reflects properties of the wavefunction of the released neutron in the nucleus and hence ground-state properties of these isotopes. Neutron capture cross-sections such as for the ¹⁴C(n,γ) ¹⁵C reaction which are of astrophysical relevance can be deduced indirectly.

The continuum discretized coupled channel method includes breakup of the projectile during a projectile–nucleus scattering process. The main new feature of the proposed reformulation is not to discretize the breakup continuum into bins, and then solve the corresponding continuum–continuum coupled equations, but rather to treat the continuum as a whole. This is accomplished by transforming the Schrödinger equation into an integral equation, separating the breakup space from the bound space by means of projection operators, and then using a two-dimensional free Greens function in the integral kernel of the breakup component. The latter is known analytically in configuration space. Iterative methods for solving this equation are considered, and an estimate of the corresponding number of floating point operations (i.e., the complexity) is presented. The complexity is not much larger than that of the standard method.

In recent years, the exploitation of the recoil-decay tagging (RDT) technique with large arrays of germanium detectors has revealed much information about the structure of heavy nuclei approaching the proton drip line. The yrast bands of the N ⩽ 93 osmium isotopes have been identified in a campaign of tagging experiments using various spectrometer arrays coupled to the RITU gas-filled separator based at the University of Jyväskylä. Trends in the yrast state excitation energies have indicated a transition from γ-soft triaxial to near-spherical shapes with decreasing neutron number. Recent experimental results for ¹⁶²Os obtained with the JUROGAM and GREAT spectrometers also indicate the importance of configurations involving the h_9/2 neutron states as the N = Z = 82 shell gaps are approached.

We have recently performed in-beam experiments using Gammasphere + FMA to measure excited states in proton-rich Au, Hg, Tl and Pb isotopes. In these studies, the use of the FMA is essential in order to differentiate evaporation residues from the large fission background which dominates the reaction cross-section. In addition, we have found that using near-symmetric reactions at bombarding energies near the Coulomb barrier is beneficial in performing these studies. By keeping the bombarding energy low, fission is minimized and the reaction products are concentrated in only a few channels. New results have recently been obtained using the ⁹⁰Zr+⁹²Mo reaction to study ¹⁸¹Tl and ¹⁸¹Pb via the 1p and 1n channels, respectively.

Low-energy excited states of ²¹⁰Ra and ²⁰⁸Ra were investigated at the Wright Nuclear Structure Laboratory of Yale University. Fusion evaporation recoils were selected using the gas-filled spectrometer, SASSYER. Delayed γ-rays, following isomeric decays, were detected at the focal plane of SASSYER with a small array of HPGe detectors. Transitions following the proposed J^π = 8⁺ isomers were observed, and the half-lives measured. The experiments are discussed and results compared to expectations from the seniority scheme.

Starting from self-consistent mean-field models, we discuss how to include correlations from fluctuations in collective degrees of freedom through symmetry restoration and configuration mixing, which give access to ground-state correlations and collective excitations. As an example for the method, we discuss the spectroscopy of neutron-deficient Pb isotopes.

The results of measurements of β-delayed and isomeric γ rays from neutron-rich nuclides produced by projectile fragmentation at the NSCL are summarized.

The structure of the neutron-rich nucleus ⁴⁵Ar has been investigated through the d(⁴⁴Ar,⁴⁵Ar)p transfer reaction. Radioactive beam of ⁴⁴Ar at 10 A MeV has been provided by the SPIRAL facility at GANIL. The protons corresponding to a neutron pick-up on bound or unbound states mechanism in ⁴⁵Ar nuclei were detected at backward angles by the detector array MUST. The transfer-like ejectiles were detected in the SPEG spectrometer. Level scheme, spin assignments and spectroscopic factors have been deduced for ⁴⁵Ar and compared to shell model predictions. These parameters will be subsequently used to infer (n, γ) cross sections in the Ar isotopic chain for astrophysical purposes.

One-nucleon removal reactions at relativistic energies have been used as a spectroscopic tool for obtaining information about the ground state of neutron-rich oxygen isotopes. Using the FRS at GSI, the longitudinal momentum distributions of the emerging fragments after breakup were measured along with the one-nucleon removal cross-sections. The relative contributions of the remaining fragments in their ground and excited states have been determined for a few cases from measurements of γ rays in coincidence with the longitudinal momentum distribution. The controversial case of ²³O has been directly addressed. Comparison of our exclusive momentum distributions for the one-neutron removal channel to theoretical momentum distributions calculated with an Eikonal model for the knockout process rendered a spin and parity of I^π = 1/2⁺ for the ²³O ground state. This result resolves the existent experimental discrepancy and supports sub-shell closure at N = 14 with a fairly pure 2s_1/2 neutron in ²³O.

Simultaneous progress in astronomical observations and nuclear physics experiments with radioactive beams offers new opportunities in nuclear astrophysics, in particular concerning the r-process and the rp-process. I review some of the open questions and recent developments, and present two recent experimental results from the new Coupled Cyclotron Facility at MSU. These are the measurement of the half-life of ⁷⁸Ni relevant for the r-process and the measurement of excited states in ³³Ar that reduce the uncertainties in the ³²Cl(p, γ)³³Ar reaction rate in the rp-process by several orders of magnitude.

Several recent experiments at the Holifield Radioactive Ion Beam Facility using neutron-rich radioactive ion beams (RIBs) are briefly described. These experiments contribute significantly to the growing list of techniques currently used with RIBs. Recent fusion-evaporation cross-section measurements below the Coulomb barrier for the ¹³²Sn + ⁶⁴Ni reaction suggest enhancement as compared to ¹²⁴Sn + ⁶⁴Ni reaction. These studies are being expanded to include reactions with ¹³⁴Sn. The g factor of the first 2⁺ state in ¹³²Te has been measured to be 0.35(5) through the recoil-in-vacuum technique. Angular distributions have been measured in the reaction ¹³C(¹³⁴Te,¹³⁵Te)¹²C at 550 MeV and used to suggest the spin and parity of a new 2109 keV state in ¹³⁵Te as , suggesting a single-particle configuration of . Decay spectroscopy may be further enhanced using a ranging-out technique to reduce the isobaric impurity of neutron-rich beams.

Differential cross sections for quasi-elastic scattering, breakup reaction as well as 1n- and 2n-transfer reactions induced by ⁶He at 25 MeV/nucleon from a ⁹Be target are reported. The experimental data were analysed in the context of the coupled-channel calculations. The internal structure of ⁶He is discussed and further studies are proposed.

The first physics results measured using the TIARA array are reported. The reaction ²⁴Ne(d,p)²⁵Ne has been studied in inverse kinematics with a radioactive beam of ²⁴Ne provided by SPIRAL at GANIL. TIARA is very compact with a high geometrical coverage for charged particles, and is designed specifically for the study of transfer reactions in inverse kinematics, with radioactive beams. From the (d,p) differential cross sections, the ground state of ²⁵Ne is assigned to have J^π = 1/2⁺ and the lowest states with J^π = 5/2⁺ and 3/2⁺ are tentatively identified at excitation energies of 1.70 and 2.05 (±0.05) MeV, respectively. Coincident gamma-ray data proved essential to resolve these two excited states. Strongly populated levels observed at 3.30 and 4.05 (±0.05) MeV are candidates for negative parity states. Further analysis of the differential cross sections is in progress, with the aim of improving the identification of the higher lying states and determining absolute spectroscopic factors.

The TRIUMF-ISAC gamma-ray escape-suppressed spectrometer (TIGRESS) is a new γ-ray detector array being developed for use at TRIUMF's Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. TIGRESS will comprise 12 32-fold segmented clover-type HPGe detectors coupled with 20-fold segmented modular Compton suppression shields and custom digital signal processing electronics. This paper provides an overview of the TIGRESS project and progress in its development to date.

We describe the behaviour of the fusion, break-up, reaction cross sections and elastic scattering of weakly bound nuclei, at near and above barrier energies. The total fusion cross sections are not affected by the break-up process at this energy regime. The elastic break-up cross sections are important at energies close and above the Coulomb barrier, even in systems with light targets, and increase the reaction cross sections. We also show that the break-up process at near and sub-barrier energies is responsible for the vanishing of the usual threshold anomaly of the optical potential and gives rise to a new type of anomaly, named by us as break-up threshold anomaly.

The level density parameters for the back-shifted Fermi gas (both without and with energy-dependent level density parameter) and the constant temperature models have been determined for 310 nuclei between ¹⁸F and ²⁵¹Cf by fitting the complete level schemes at low excitation energies and the s-wave neutron resonance spacings at the neutron binding energies. Simple formulae are proposed for the description of the two parameters of each of these models, which involve only quantities available from the mass tables. These formulae may constitute a reliable tool for extrapolating to nuclei far from stability, where nuclear level densities cannot be measured.

We investigate the tensor correlation in He isotopes. We extend the model space of ⁴He with the shell model approach to incorporate the tensor correlation, and π meson-like 0⁻ particle–hole correlation is favoured. Based on the 'tensor-correlated ⁴He + n(+n)' model, it is found that the tensor correlation affects the LS splitting in ⁵He and the 0⁺₂ state of ⁶He due to the strong Pauli blocking for the p_1/2 orbit of neutrons. We also obtain a reliable ⁴He–n interaction including the tensor correlation, which improves the behaviour of the d- and f-wave phase shifts in the ⁴He + n system.

An indirect method for determining cross sections of reactions proceeding through a compound nucleus is presented. Some applications of the Surrogate nuclear reaction approach are considered and challenges that need to be addressed are outlined.

The newly commissioned TIARA array has been coupled for the first time to the VAMOS spectrometer and the EXOGAM germanium array to study nucleon transfer reactions in inverse kinematics and using beams of low intensity, which are typical of radioactive beam experiments. This set-up offers a high geometrical efficiency for the charged particle detection, a high efficiency for γ-ray detection and a final energy resolution only limited by the Doppler broadening. This report demonstrates the potential of such an apparatus to study single-nucleon transfer reactions with radioactive nuclear beams. A beam of ¹⁴N at 10.6 MeV/nucleon with an intensity of 10⁵ s⁻¹ was directed onto a CD₂ target of 1 mg cm⁻². Proton angular distributions have been measured for the population of ¹⁵N in the ground state and in excited states at 7.15 and 7.56 MeV. Transferred l-values deduced from comparison to DWBA calculations are in very good agreement with the well-known shell structure of ¹⁵N. We have therefore demonstrated the effectiveness of this set-up in studying nucleon transfer reactions in inverse kinematics and with low-intensity beams.

The recent status of theoretical and experimental studies of giant dipole resonances in nuclei is presented with the emphasis on: (1) giant dipole resonances in highly excited nuclei, (2) multiple-phonon resonances and (3) pygmy dipole resonances in neutron-rich nuclei. In particular, the description of these resonances within the framework of the phonon damping model is discussed in detail.

Studies of the ¹⁶O(⁹Be,α⁷Be)¹⁴C, ⁷Li(⁹Be,α⁷Li)⁵He and ⁷Li(⁹Be,ααt)⁵He reactions at E_beam = 70 and 55 MeV have been performed using resonant particle spectroscopy techniques. The ¹¹C excited states decaying into α + ⁷Be(gs) are observed between 8.5 and 13.5 MeV. The α + ⁷Li(gs), α + ⁷Li* (4.652 MeV) and t+⁸Be(gs) decays of ¹¹B excited states between 9 and 19 MeV are observed. The decay processes are used to indicate the possible three-centre 2α + ³He (2α + ³H) cluster structure of observed states. This cluster structure is more prominent in the positive-parity states, where two rotational bands with large deformations are suggested. Excitations of some of the observed T = 1/2 resonances coincide with the energies of previously measured T = 3/2 isobaric analogues of the ¹¹Be states, indicating that these states may have mixed isospin.

The ²⁰⁸Pb(p,p'e⁻) reaction has been studied at a proton energy of 17.3 MeV. Singles data show E0 transitions from the 0⁺₂ and 0⁺₃ states at 4868 and 5241 keV, respectively, to the ground state. Proton–electron gated spectra indicate that few electrons from the 0⁺₂ state are in coincidence with backscattered protons, while those from the 0⁺₃ state are somewhat more abundant. From the singles spectra, an upper limit for the E3(0⁺₃ → 3⁻₁)/E0(0⁺₃ → 0⁺₁) branching ratio of less than four has been measured. This observation is in agreement with previous predictions for a two-phonon octupole excitation.

Structures have been identified built upon the K^π = 43/2⁽⁻⁾ and K^π = 43/2⁺ isomeric states in ¹⁸³Os. Although these sequences appear quite irregular, their properties can be understood if the angular momentum is built up, to a large degree, from multiple phonons. These vibrations are found to compete with rotations in generating angular momentum.

The exploitation of the recoil-decay tagging (RDT) technique has reinvigorated experimental investigations of the shape coexistence phenomenon in heavy neutron-deficient nuclei. In a recent experiment using the JUROGAM and GREAT spectrometers in conjunction with the RITU gas-filled separator, excited states have been investigated in the light platinum isotopes. In addition to extending the yrast sequences in ¹⁷⁰Pt and ¹⁷²Pt, the first observation of excited states in the odd-N isotopes, ¹⁶⁹Pt and ¹⁷³Pt, is reported. The bands are discussed in terms of trends in level excitation energies as a function of neutron number.

Iridium nuclei at and beyond the proton drip line have been studied via fusion evaporation reactions. A reaction of ⁹²Mo(⁷⁸Kr, p2n) at a beam energy of 360 MeV and target thickness 500 µg cm⁻² was employed to study ^167,167mIr. A reaction of ¹¹²Sn(⁵⁸Ni, p2n) at a beam energy of 266 MeV and target thickness 500 µg cm⁻² was used to study ^169,169mIr. The experiments were performed at the University of Jyväskylä utilizing the RITU separator in conjunction with the focal plane GREAT spectrometer and the JUROGAM Ge array at the target position. Excited states feeding both the ground state and isomeric state in ¹⁶⁹Ir, excited states feeding the ground state of ¹⁶⁷Ir and the ground state alpha decay of ¹⁶⁵Re have been observed for the first time along with excited states feeding ^167mIr. Experimental spectroscopic factors and reduced widths have been obtained for the proton and alpha decay of these nuclei.

The production of α-particles in the reactions ^6,7Li+²⁸Si was studied as a means to disentangle the various reaction channels at near-barrier energies. The competition between compound and direct reactions was determined by using the shape of angular distributions and statistical model calculations. DWBA calculations were also performed to probe the various direct channels. It was found that, approaching barrier, transfer channels are the most dominant for both reactions. For ⁷Li+²⁸Si d-transfer is one of the contributing channels without excluding t-transfer, while for ⁶Li+²⁸Si, n-transfer and p-transfer have substantial contribution but without excluding d-transfer.

The γ decay of the nuclei ^124,125Ba has been investigated with the EUROBALL array, using the reaction ⁶⁴Ni+⁶⁴Ni at E_beam = 255 and 261 MeV. Six new E1 transitions have been found in the nucleus ¹²⁵Ba, suggesting a significant role of octupole correlations in the origin of its parity doublets. The J^π = 3⁻ level of the nucleus ¹²⁴Ba has been identified for the first time. Its excitation energy is in very good agreement with a prediction based on a microscopic model including octupole interactions.

High-spin terminating bands in heavy nuclei were first identified in nuclei around ¹⁵⁸Er₉₀. 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 ¹⁵⁷Er 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 ¹⁷⁴Hf 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.

Experimental properties of nearly degenerate ΔI= 1 doublet bands, which are built on the same single-particle configuration, are tested against three criteria for spontaneous formation of chirality in nuclei via the coupling of three mutually perpendicular angular momenta. Four representative nuclei, ¹³⁴Pr, ¹³⁰Cs, ¹⁰⁴Rh and ¹⁰⁵Rh are discussed. The doublet bands in these nuclei exhibit chiral characteristics except for ¹³⁴Pr, which shows a significant difference in electromagnetic properties between the two candidate chiral structures.

A summary of recent results of research at iThemba LABS is given. This includes high-resolution measurements of the fine structure of isoscalar giant quadrupole resonances, a new programme to measure fusion barrier distributions for reactions leading to the formation of superheavy elements, measurements of high-energy γ-rays from (p,γ) reactions using the AFRODITE array of HpGe clover detectors, and a comparison of the vibrational band structures of ¹⁶⁰Yb, measured with the AFRODITE array, with the X(5)-β²ⁿ model. A summary of future developments is given.

Experimental results in Lu isotopes in the A ≈ 160 mass region have been interpreted as indicating the existence of the wobbling mode proposed by Bohr and Mottelson. Despite the success analysing the obtained data by use of the phenomenological particle-plus-rotor model (PRM) by Hamamoto, questions still remain. These questions relate to the lack of evidence of even–even wobbling systems, the anharmonicity of the wobbling spectrum and the nonlinear spin dependence of the excitation energy. An extension of the original Bohr–Mottelson model is suggested that incorporates spin dependence into the moment of inertia which provides a possible mechanism for explaining the latter two questions, whilst phenomenological arguments are adopted for the first.

In order to study proton single particle states in exotic nuclei, the (α, t) reactions in inverse kinematics at 30–60 A MeV have been measured by using a liquid helium target. Its applicability is discussed from the aspects of the kinematical matching conditions comparing those for the (d, n) reactions. As a demonstration, the measurement of the (α, t) reaction with an ²²O beam at 35 A MeV, populating excited states in ²³F, performed at the RIPS facility in RIKEN, is presented. A candidate of the πd_3/2 single particle state was found at E_x = 4.1 MeV by a DWBA analysis for the population probability and the angular distribution. The energy of the newly assigned state is discussed in the context of the πd_5/2–πd_3/2 spin–orbit splitting as a function of the occupation number of d_5/2 neutrons.

Binding energies determined with high accuracy provide smooth derivatives of the mass surface for analysis of shell and pairing effects. Measurements with the Penning trap mass spectrometer ISOLTRAP at CERN-ISOLDE were made for ⁵⁶⁻⁵⁷Cr for which an accuracy of 4 × 10⁻⁸ was achieved. Analysis of the mass surface for the supposed new N = 32 shell closure rather indicates a sub-shell closure, but of a different nature than known cases such as ⁹⁴Sr.

The masses of ten neutron-deficient nuclides near the N = Z line with A = 64–80 have been measured with the direct time-of-flight technique using the CSS2 cyclotron as a high-resolution spectrometer. All measured masses agree with the 2003 atomic mass evaluation and are compared to the predictions of the finite range droplet model. The atomic mass excesses obtained for ⁶⁸Se and ⁸⁰Y are −53.958(246) MeV and −60.971(180) MeV, respectively. The new results for ⁶⁸Se and ⁸⁰Y are compared to other recent experimental values.

The mass of radionuclides contribute to a variety of fundamental studies including tests of the weak interaction and the standard model. The limits of mass measurements on exotic nuclides have been extended considerably by the Penning-trap mass spectrometer ISOLTRAP at the ISOLDE facility at CERN. Recent ISOLTRAP measurements are summarized and current technical improvements are outlined.

Exotic nuclei generated via projectile fragmentation and fission are characterized by a large phase-space population. Thus precision experiments based on kinematical observables are difficult and require special methods. The experiments described in this contribution are based on special ion-optical spectrometer modes or on phase-space reduction via cooling of stored ions. The studies are performed with the projectile fragment separator FRS and the storage-cooler ring ESR at GSI.

It is frequently assumed that matter in the mass range A ⩾ 20 is processed through the NeNa-cycle during hydrogen-burning nucleosynthesis. The existence of such a reaction cycle implies that the ²³Na(p,α)²⁰Ne reaction is more likely to occur than the competing ²³Na(p,γ)²⁴Mg reaction. Recently evaluated thermonuclear rates for both reactions carry large uncertainties and allow for both possibilities, a closed and an open NeNa-cycle. We measured the ²³Na(p,γ)²⁴Mg reaction at the Laboratory for Experimental Nuclear Astrophysics (LENA). The present experimental results reduce the ²³Na+p reaction rate uncertainties significantly. We demonstrate that a closed NeNa-cycle does not exist at elevated stellar temperatures of T = 0.2–0.4 GK. The implications for the nucleosynthesis in classical novae are discussed.

Natural parity states of odd-A and even–even nuclei in the middle and in the second half of the 1f_7/2 shell are described by shell-model calculations in the full pf configuration space. Multi-quasiparticle rotational bands and, in some cases, band crossings have been revealed. The ground-state bands experience a change from collective to non-collective regime, approaching the termination in the 1fⁿ_7/2 space. Evidence of the vibrational γ-band is discussed in ⁵²Fe.

Studies of the ¹²C(¹²C,⁸Be+⁸Be)⁸Be and ¹²C(¹²C,⁸Be+¹²C(0⁺₂))α reactions, using a large array of strip detectors, have provided evidence for states in ¹⁶O and ²⁰Ne which decay to α-cluster states in ⁸Be and ¹²C. The spins of the resonances have been determined which allows the energy-spin systematics to be characterized.

For decades, the study of the gamma-ray decay from quantal states of the atomic nucleus has played a pivotal role in discovering and elucidating a wide range of phenomena. Each major technical advance in gamma-ray detection devices has resulted in significant new insights into the structure of nuclei. To date, these advances have culminated in the construction of 4π arrays of escape-suppressed spectrometers. The global consensus of opinion is that the next major step in γ-ray spectroscopy involves abandoning the concept of a physical suppression shield and achieving the ultimate goal of a 4π Ge ball using the technique of γ-ray energy tracking in electrically segmented Ge crystals. The resulting spectrometer will have an unparalleled level of detection power for nuclear electromagnetic radiation. Its sensitivity for selecting the weakest signals from exotic nuclear events will be enhanced by a factor of up to 1000 relative to its predecessors. It will have an unprecedented angular resolution making it ideally suited for high-energy resolution even at recoil velocities up to 50% of the velocity of light. Therefore, it is ideally suited to be used in conjunction with the new generation of radioactive beam accelerators or existing stable beam facilities. In Europe, a collaboration has been established to construct a 4π tracking spectrometer called AGATA (advanced gamma tracking array). This collaboration has signed a Memorandum of Understanding for the first phase of the project to perform the research and development necessary to finalize the technology for gamma-ray tracking and hence fully specify the full 4π spectrometer. The status of this first phase of the AGATA project will be reported.

The NuSTAR facility at the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt with its high intensity secondary beams of short-lived ions at relativistic energies will be unique worldwide. The combination of relativistic in-flight fragmentation and fission products with storage rings and the simultaneous availability of stored antiprotons and electrons will allow unique experiments to be performed that will address the fundamental and long-standing questions of low energy nuclear physics. A brief review of the experimental capabilities that have been proposed for experiments at the Super-FRagment-Separator at FAIR and a selection of the physics questions that will be addressed is given. Only a short glimpse at the physics questions being addressed and the observables providing answers to these questions can be given here.

A modified version of the previously proposed exponential model with pairing attenuation for the well-deformed even–even nuclei has been applied to predict the energy levels of doubly even actinide nuclei. Satisfactory results are obtained by that model as compared with the experimental results. The backbending phenomena are successfully described and discussed. A further comparison with the main previous models has been undertaken to confirm its validity in the heavy-nuclei region.

We study isovector giant monopole resonances in spherical nuclei using the time-dependent Hartree–Fock method with different Skyrme forces. The aim of the investigation is to study how, for example, mass number and neutron excess influence the isovector giant monopole resonances and their mixing with isoscalar modes. We also study how nuclear matter properties, such as the asymmetry energy, of different Skyrme forces affect the behaviour of giant resonances. We find isovector and isoscalar modes to be strongly mixed and that there is little correlation between asymmetry energy and isovector resonance energy.

The halo factor is one of the experimental data which aims to describe a distribution of neutrons in nuclear periphery. In this work we use the relativistic mean field model and calculate the neutron excess factor Δ_B defined in the text. The results of the calculations are compared to the measured data.

Fusion and incomplete fusion evaporation channels were studied in the ⁷Li +¹⁶⁴Dy reaction at the INFN Laboratory, Legnaro, Italy. The Tandem-XTU accelerator was used to accelerate a beam of ⁷Li ions to 55 MeV. The highly sensitive GASP γ-detector array coupled with the selectivity of the ISIS charged particle ΔE–E telescope array provided a powerful tool for studies of high spin states in the fusion and incomplete fusion reaction products. Rotational sequences in the Er and Tm isotopes around A = 166 have been observed and extended to higher spin states. Comparisons of the experimental data with the results of the cranked shell model give some insight into the configuration dependence of the crossing of the ground-state band with the aligned i_13/2 two quasineutron configuration.

In order to study direct reactions of exotic beams on light particles target, we have developed a new detector: MAYA. This detector is an active target, using the gas as target and as a detection material. With such a device, thick target can be used without resolution loss. Furthermore, excitation functions can be studied from the incident beam energy down to the detection threshold with the same setting. This detector uses a multiplexed read-out electronic for the pads of the segmented detection plan. Several experiments have already been performed, providing results about detector characteristics.

We present the failure of the standard coupled-channels method in explaining inelastic scattering together with other observables such as elastic scattering, excitation function and fusion data. We use both microscopic double-folding and phenomenological deep potentials with shallow imaginary components. We argue that the solution of the problems for the inelastic scattering data is not related to the central nuclear potential, but to the coupling potential between excited states. We demonstrate that these problems can be addressed in a systematic way by using a different shape for the coupling potential instead of the usual one based on Taylor expansion.

The projectile fragmentation of ⁹²Mo at Elab = 500 A MeV has been studied at the European large-scale facility SIS/FRS at GSI, Darmstadt, Germany. The produced isotopes have been identified in Z and A numbers by using the Bρ–ΔE–TOF method. The results of the isotopic production cross sections will be presented. The data will be used to test the predictive power of the empirical parametrizations (EPAX) and fragmentation models (ABRABLA) to determine production cross sections. The measured data provide a precise knowledge of the expected production rates of secondary beams of N ≃ Z nuclei via projectile fragmentation.

Particle rotor model calculations have been performed in the mass 130 region, to elucidate the salient features of chiral rotation in ¹³²Pr and ¹³⁴Pr. The laboratory frame description yields the splitting between bands and follows the transition probabilities evolution from planar to chiral and then axial regions.

A beam of 28 MeV ⁸He particles with an average intensity 2 × 10⁵ ions s⁻¹, produced by the SPIRAL facility at GANIL, was used to initiate fusion–evaporation reactions in thick targets of ²⁰⁸Pb and ²⁰⁹Bi. Excited states of ²¹²Po and ²¹³At were populated in (⁸He,4n) reactions. The emitted γ-rays were detected using the EXOGAM array composed of four Compton suppressed germanium Clover detectors in a close geometry configuration. Preliminary results show that ²¹²Po has been populated to high spin (I ≃ 14) with a significantly increased yield compared with our previous ⁸He beam experiment. An apparently increased relative population of states up to 12⁺ was observed compared with published results from a ²⁰⁸Pb(⁹Be,αn)²¹²Po reaction at 48 MeV. Evidence is presented for a previously unreported de-excitation pathway: 69 keV (13⁻→ 12⁺). States up to I^π = (39/2⁻) have also been observed in ²¹³At.

The nucleus ¹⁵²Sm is characterized by a variety of low-energy collective modes, conventionally described as rotations, β vibrations and γ vibrations. Recently, it has been suggested that ¹⁵²Sm is at a critical point between spherical and deformed collective phases. Consequently, ¹⁵²Sm is being studied by a variety of techniques, including radioactive decay, multi-step Coulomb excitation, in-beam (α, 2nγ) γ-ray spectroscopy and (n, n'γ) spectroscopy. The present work focuses on the latter two reactions; these have been used to investigate the low-lying bands associated with the octupole degree of freedom, including one built on the first excited 0⁺ band. In addition, the K^π = 4⁺ hexadecapole vibrational band has been identified.

We present pycnonuclear reaction calculations for a one-component ionic crystal at zero temperature considering different theoretical approaches. The rates depend directly on the determination of the astrophysical S-factor at low energies, which has been obtained through the barrier penetration formalism. A totally parameter-free model for the real part of the nuclear interaction has been employed in the calculation of ¹²C+¹²C fusion cross sections.

In the hot interiors of dense stellar plasma, the equilibrium CNO cycle converts most of the carbon and oxygen into nitrogen. We discuss implications of new measurements concerning the modified thermonuclear CNO reaction rates and the chemical abundance evolution of the stellar core as a function of the temperature. We show that strong CNO abundance variations occur if non-extensive statistical effects, connected to memory plasma effects and long-range force, are taken into account.

A new direct technique using the CIME cyclotron as a high-resolution mass spectrometer is being developed in order to measure the masses of exotic nuclei. Tests have been performed to check the feasibility of the method with a mixed beam of stable ions extracted from the SPIRAL ion source and injected into the CIME cyclotron. Preliminary results obtained with this new technique are presented and discussed.

The triaxial strongly deformed (TSD) bands in ¹⁶⁷Lu were populated by the ¹²³Sb(⁴⁸Ca, 4n) reaction with a beam energy of 203 MeV. Gamma rays, requiring five fold or more in prompt coincidence, were detected with the Gammasphere spectrometer. Of particular interests are TSD bands 1 and 2 which have previously been interpreted as zero phonon and one phonon wobbling bands, respectively. Using the Doppler shift attenuation method (DSAM), a preliminary transition quadrupole moment of 6.9^+0.3_−0.3 eb was extracted for the TSD1 band. Data analysis continues for TSD2 which is considerably more weakly populated.

Nuclear structure of ¹³²Ba is investigated within a framework of the pair-truncated shell model. The model reproduces experimental energy levels of the magnetic dipole band with the ν(h²_11/2) ⊗ π(h_11/2g_7/2) configuration. From the analysis of its structure, it turns out that two angular momenta of valence neutrons and protons gradually close as total spin increases.

Recent measurements of the cross sections for the diffractive breakup of ¹¹Be on a light (¹²C) target have been reported. These data cover a fraction of the final-state three-body phase space and cuts on these data exhibit resonant structures in the neutron–¹⁰Be continuum. These breakup data provide a motivation to test the coupled discretized continuum channels method in the context of the spectroscopy of continuum states in ¹¹Be and similar neutron-rich systems near the dripline.

A measurement of the half-life of ⁶²Ga was made as part of a programme of high-precision superallowed Fermi β decay studies at the ISAC radioactive beam facility. The experiment was conducted by counting β⁺ particles from the decay of ⁶²Ga in a 4π gas proportional counter. The half-life was measured to be 116.01 ± 0.19 ms. Several parameters were varied during the experiment to test for systematic effects, but no significant effects were found.

Several nuclei in the A ∼ 190 region have been studied following deep-inelastic reactions using a 460 MeV ⁸²Se projectile impinging upon a thick ¹⁹²Os target. The GASP array (at the Legnaro National Laboratory in Italy) was used to measure the resulting γ-decays. The previously reported near-yrast structure of ¹⁹¹Os is extended to a isomer, at an energy of 2640 keV. Branching ratios for ΔI = 1 and ΔI = 2 transitions in the band have been measured, giving |(g_K − g_R)/Q₀| = 0.022(3) and 0.024(7) for transitions from the and states respectively. These are consistent with the theoretical calculation for the proposed ν11/2⁺[615] configuration of the band. Nilsson plus BCS calculations reveal that the isomer is likely to have a {ν11/2⁺[615] ⊗ π11/2⁻[505] ⊗ π9/2⁻[514]} configuration with . This yields an implied reduced hindrance of f_ν= 1.9, in accordance with empirical systematics of K isomers in the A ∼ 180–190 region.

Chirality in atomic nuclei is a direct consequence of the existence of triaxial nuclear shapes. This phenomenon is known to exist in the A ∼ 130 region. We have now observed several pair of bands built upon the negative parity configuration, πg⁻¹_9/2 ⊗ νh_11/2, in Rh and Tc isotopes in the A ∼ 104 region which can be understood in terms of the phenomenon of chiral symmetry breaking. Results of the search for chiral bands in ¹⁰⁶Ag are presented in the current paper.

The half-lives of two isomeric states in ¹²⁵Sb have been measured as 5.7(3) and 28.0(7) µs respectively. Conversion coefficients for the transitions depopulating the isomeric states have also been measured and based on these, the 1971.8 keV state is assigned a spin and parity of 15/2⁻ and the state at 2112.7 keV is assigned a spin and parity of 19/2⁻. These states have been interpreted as the g_7/2 proton coupled to the known isomeric 5⁻ and 7⁻ states in the ¹²⁴Sn core.

A beam of ²⁶Mg at 160 MeV incident on a thin target of ¹⁵⁰Nd was used to initiate deep-inelastic and multi-nucleon transfer reactions. The gamma-decay of the fragments produced in the reaction was studied using the EUROBALL IV array of escape suppressed Ge detectors at Strasbourg combined with the binary reaction spectrometer used to detect the projectile-like fragments. Preliminary results from the experiment are presented.

Three-alpha resonance states in ¹²C are investigated by using the method of analytic continuation in the coupling constant combined with the complex scaling method (ACCC+CSM). We obtain a broad 0⁺ resonance state with energy of E_r = 1.66 MeV and width of Γ = 1.48 MeV, which has a similar structure as the second 0⁺ state.

In the present work, we analyse the behaviour of the pseudospin symmetry (PSS) in heavy nuclei (²⁰⁸Pb) in the framework of the relativistic Hartree–Fock approximation (RHFA). The quasidegeneracy of the pseudospin partners and the similarity of the small F components of their respective Dirac spinors have a somewhat lower degree of accuracy than in the relativistic mean field approximation (RMFA). Both properties improve when the number of nodes of the small component increases, as happens in the RMFA. The behaviour of the single-particle potentials appearing in the Dirac equation of the pseudospin partners is analysed. There is no dominance of the pseudocentrifugal barrier (PCB) compared to the pseudospin-orbit potential (PSOP). In the RHFA, the PSS is an approximately satisfied symmetry in nuclei and its dynamical character is reinforced with respect to the RMFA.

A newly developed CAlorimeter TElescope (CATE) is employed in the fast beam RISING γ-campaign with relativistic energies at the FRS at GSI. CATE consists of nine Si-CsI(Tl) detector telescopes for position and ΔE − E measurements. It registers the scattering angle and identifies the charge (Z) and the mass (A) of exotic heavy ions produced after secondary fragmentation or Coulomb excitation.

A number of high-lying excited states in ¹⁴C, above the α-decay threshold, are believed to exhibit molecular-like configurations of three α-particles and two valence neutrons. The nature of these states can be determined by the measurement of their spins, parities and partial decay widths. An experiment using the ¹²C(¹⁶O,¹⁴O)¹⁴C reaction was performed recently at the ISL facility at the Hahn-Meitner-Institut, Berlin. The ¹⁴O ejectile was detected using a Q3D spectrometer at small forward angles. The recoil's decay products were detected in co-incidence using two double-sided silicon strip detectors at backward angles. This technique allows the possibility of a full kinematic reconstruction of the reaction, as well as enhanced background suppression. Analysis of the data is currently underway and the latest results are shown here.

Astrophysical reaction rates are sensitive to the parity distribution at low excitation energies. We combine a formula for the energy-dependent parity distribution with a microscopic–macroscopic nuclear level density. This approach describes well the transition from low excitation energies where a single parity dominates to high excitations where the two densities are equal.

The two charge exchange reactions ¹⁴N(d, ²He)¹⁴C and ¹⁴N(³He, t)¹⁴O were studied with high resolution in order to identify the Gamow–Teller (GT) strength distribution starting from the ground state (g.s.) of ¹⁴N in the β⁻ and β⁺ directions. The isospin symmetry in the A = 14 mass system is investigated. An overview of the main features of the experimental investigation is summarized here.

Neutron-rich sdf-shell nuclei have attracted a great deal of international interest, both theoretically and experimentally. There is an increasing interest in using deep-inelastic reactions to obtain spectroscopic information about these exotic nuclei. New results obtained from two such experiments are presented here. The highly sensitive GASP array was used to measure the γ decays of previously unobserved yrast and near yrast states of ³⁴P which were populated when 230 MeV ³⁶S ions were incident on a thick target of ¹⁷⁶Yb. In addition, a recent investigation of the spectroscopy of neutron-rich P and S isotopes has been undertaken with 215 MeV ³⁶S ions incident on a thin target of ²⁰⁸Pb using the CLARA Ge detector array in conjunction with the PRISMA magnetic spectrometer. Preliminary results from this experiment are presented here.

The ¹²C(α,γ)¹⁶O reaction rate at stellar helium burning temperatures is very important in nuclear astrophysics. The reduced α-widths of the 6.917 MeV and 7.117 MeV states in ¹⁶O will greatly influence the E2 and E1 transition part of the ¹²C(α,γ)¹⁶O reaction rate. It is known that one can determine the reduced α-width of the 6.917 MeV state in ¹⁶O by measuring the ¹²C(α,α)¹²C reaction. Many experimental efforts have gone into the study of an elastic scattering on ¹²C, where the systematic error of the reduced α-width of the 6.917 MeV state has to be very carefully analysed. An R-matrix calculation was performed to determine the systematic error of the reduced α-width of the 6.917 MeV state. A one-channel, and multi-level approximation in the R-matrix formalism was used, and the partial waves of l = 0 to l = 5 were included in the calculation. The calculated cross sections were fitted to the previous data. The dependence of the reduced α-width of the 6.917 MeV state in ¹⁶O on the detecting angle position, the incident beam energy and the absolute normalization constant of the cross section was obtained. Our analysis could be helpful in designing a new ¹²C(α,α)¹²C measurement, and determining the systematic error of the reduced α-width of the 6.917 MeV state in ¹⁶O.

In order to study the Gamow–Teller (GT) transitions in the fp-shell nucleus ⁶⁴Cu, the ⁶⁴Ni(³He, t)⁶⁴Cu charge-exchange reaction was investigated at MeV/nucleon [1]. The outgoing tritons were momentum analysed by the Grand Raiden spectrometer at 0°. The very high energy resolution of 35 keV (FWHM) allowed the separation of individual levels in the excitation energy region from 0 to 3.5 MeV. An angular distribution analysis was performed for the observed transitions to these states. In addition to the ground state (g.s.), known to be a J^π = 1⁺ GT state, several excited states showed L = 0 nature, making them candidates of GT states. At higher excitation energies, the level density becomes very high and a bump-like structure, the so-called GT Giant Resonance, dominates the spectrum.

An experiment has been performed in Jyväskylä, Finland, using Jurogam in conjunction with RITU and GREAT. This experiment populated several extremely neutron-deficient nuclei around the mass-140 region of the nuclei chart, using the ⁹²Mo(⁵⁴Fe, α2n) reaction at 245 MeV. Analysis of these data has revealed several previously unobserved isomeric states, in several nuclei. One of these has been assigned to ¹⁴³Dy with a half-life of 1.2 ± 0.3 µs. The energies of the prompt γ rays in the band built upon the isomer are in agreement with those previously observed.

We have measured elastic cross sections of the scattering of ⁶He at E_Lab = 14, 16, 17, 18 and 22 MeV on ²⁰⁸Pb in the angular ranges of 20°–64° and 135°–170°. A significant amount of ⁴He events is found at energies well below the Coulomb barrier, that becomes dominant above it. Optical model calculations have been performed including a dynamic polarization potential. Very large imaginary diffuseness parameter is needed in order to describe the experimental distributions.

Average neutron resonance parameters are used for adjusting inputs to optical and statistical modal calculations. In the past, J^π assignments of resonances were only known for a few nuclides and the J-dependence of S₀ could not be established. High resolution data on resonance parameters (E₀, Γ_n, J^π) are now available and the J-dependence of S₀ has been re-examined. Our analysis for 32 odd spin nuclides gives the J-dependence of S₀ and thus justifies the spin–spin term in the optical model.

An experimental spectroscopic investigation of ³⁵Al has been performed. The delayed neutron and γ spectra, following the β decay of ³⁵Al, have been measured using the delayed neutron detector array TONNERRE coupled with high efficiency γ detectors. A detailed analysis of such spectra allows one to extract the level schemes of its daughters. These levels are compared with the few previously existing data and shell-model calculations. Based on triple β–γ–n coincidences eight new levels above the neutron separation energy in ³⁴Si were for the first time observed.

A new facility for the production of polarized bremsstrahlung has been built at the superconducting electron accelerator ELBE of the Forschungszentrum Rossendorf. The bremsstrahlung facility and the detector setup are designed such that the background radiation due to scattering of photons and production of neutrons is minimized allowing for experiments close to and above particle separation energies in nuclei. First results of photon-scattering and photo-dissociation experiments on ^92,98,100Mo are presented. The results are compared to recent cross-section calculations for astrophysical networks.

The γ-decay of the GDR in the ¹³²Ce compound nuclei produced by the reaction ⁶⁴Ni+⁶⁸Zn at E_beam = 300 MeV, 400 MeV, 500 MeV (E* of 100 MeV, 150 MeV and 200 MeV) has been measured. We have detected heavy recoil nuclei, light charged particles and γ-rays. The data obtained with the symmetric reaction ⁶⁴Ni+⁶⁸Zn indicate emission from a fully equilibrated compound nucleus as deduced from the analysis of charged particle spectra. The GDR parameters are found to be consistent with the predictions of the thermal fluctuation model.

BaF₂ detectors for picosecond gamma-ray decay lifetime measurements have been installed into the 8π gamma-ray spectrometer as a proof-of-principle for a possible installation of a full array of ten detectors. Using four detectors a test measurement of the half-life of the 2⁺ state in ¹⁵²Sm resulted in a value of 1.33(6) ns, compared with a published value of 1.396 ns. Measurements with a ²⁶Na stopped beam were performed with various master-trigger conditions. Using a master trigger of germanium–SCEPTAR–BaF₂ OR BaF₂–BaF₂, the FWHM of the BaF₂–BaF₂ triggered events was found to be ∼290 ps compared with ∼1.9 ns for the germanium–SCEPTAR–BaF₂ triggered events. Simulations using GEANT4 of a suggested BaF₂ lifetime measurement system have been carried out. These illustrate the considerable gain in spectrum quality which can be expected using simple add-back protocols.

Excited states in ¹⁹⁰Tl have been studied experimentally using the ¹⁶⁰Gd(³⁵Cl, 5n) reaction, and resulted in the identification of a strongly coupled band based on the πh_9/2 ⊗ νi_13/2 configuration with oblate deformation. Combining with the results from the previous α-decay of ¹⁹⁴Bi, spin values have been proposed for the πh_9/2 ⊗ νi_13/2 oblate band in ¹⁹⁰Tl. This oblate band shows low-spin signature inversion. It is the first experimental observation of low-spin signature inversion for a band associated with the oblate πh_9/2 ⊗ νi_13/2 configuration.