Search

We have performed the first direct measurement of the 83Rb(p,g) radiative capture reaction cross section in inverse kinematics using a radioactive beam of 83Rb at incident energies of 2.4 and 2.7 A MeV. The measured cross section at an effective relative kinetic energy of Ecm = 2.393 MeV, which lies within the relevant energy window for core collapse supernovae, is smaller than the prediction of statistical model calculations. This leads to the abundance of 84Sr produced in the astrophysical p process being higher than previously calculated. Moreover, the discrepancy of the present data with theoretical predictions indicates that further experimental investigation of p-process reactions involving unstable projectiles is clearly warranted., 6 pages, 4 figures, published in Physical Review Letters

A technique has been developed and tested to automatically adjust multiple electrostatic or magnetic multipoles on an ion optical beam line – according to a defined optimization algorithm – until an optimal tune is found. This approach simplifies the process of determining high-performance optical tunes, satisfying a given set of optical properties, for an ion optical system. The optimization approach is based on the particle swarm method and is entirely model independent, thus the success of the optimization does not depend on the accuracy of an extant ion optical model of the system to be optimized. Initial test runs of a first order optimization of a low-energy ( 60 keV) all-electrostatic beamline at the NSCL show reliable convergence of nine quadrupole degrees of freedom to well-performing tunes within a reasonable number of trial solutions, roughly 500, with full beam optimization run times of roughly two hours. Improved tunes were found both for quasi-local optimizations and for quasi-global optimizations, indicating a good ability of the optimizer to find a solution with or without a well defined set of initial multipole settings.

In planar GaAs microcavities in a magnetic field up to 5 T perpendicular to the structure growth plane, under conditions of resonant pulsed pumping to a point close to the inflection point of the lower dispersion curve, Zeeman splitting of the spin sublevels of the polariton condensate is observed. This is accompanied by a significant change in the degree of circular polarization and the second-order correlator g2(0). It is found that the correlator is different for the spin sublevels of the polariton condensate, split in a magnetic field. In particular, correlator measurements indicate different condensation thresholds for the spin sublevels. The correlator values initially differing in terms of the absence of a field increase, reach a maximum, and then decrease and become equal for different polarizations in a field of 5 T.

The Super Separator Spectrometer (S3S3) facility is developed in the framework of the SPIRAL2 project [1]. S3S3 has been designed to extend the capability of the facility to perform experiments with extremely low cross sections, taking advantage of the very high intensity stable beams of the superconducting linear accelerator of SPIRAL2. It will mainly use fusion-evaporation reactions to reach extreme regions of the nuclear chart: new opportunities will be opened for super-heavy element studies and spectroscopy at and beyond the driplines. In addition to our previous article (Dechery et al. [2]) introducing the optical layout of the spectrometer and the expected performances, this article will present the current status of the main elements of the facility: the target station, the superconducting multipole, and the magnetic and electric dipoles, with a special emphasis on the status of the detection system SIRIUS and on the low-energy branch which includes the REGLIS3 system. S3S3 will also be a source of low energy radioactive isotopes for delivery to the DESIR facility.

The systematic study of fission fragment yields under different initial conditions has provided valuable experimental data for benchmarking models of fission product yields. Nuclear reactions using inverse kinematics coupled to the use of a high-resolution spectrometer with good fragment identification are shown here to be a powerful tool to measure the inclusive isotopic yields of fission fragments. In-flight fusion-fission was used in this work to produce secondary beams of neutron-rich isotopes in the collisions of a 238U beam at 24 MeV/u with 9Be and 12C targets at GANIL using the LISE3 fragment separator. Unique identification of the A, Z, and atomic charge state, q, of fission products was attained with the $\Delta E$ -TKE-B $\rho$ -ToF measurement technique. Mass, and atomic number distributions are reported for the two reactions. The results show the importance of different reaction mechanisms in the two cases. The optimal target material for higher yields of neutron-rich high-Z isotopes produced in fusion-fission reactions as a function of projectile energy is discussed.

The authors would like to thank the State of Bavaria for financial support. T.A-N. has been supported in part by the Academy of Finland through its CoE grants 251748 and 284621. I.G.S. has been supported by IBS-R024-D1, the Australian Research Council's Discovery Projects funding scheme (project DE160100167), and the Dynasty Foundation. We study the influence of spatial confinement on the second-order temporal coherence of the emission from a semiconductor microcavity in the strong coupling regime. Provided by etched micropillars, the confinement has a favorable impact on the temporal coherence of solid state quasi-condensates that evolve in our device above threshold. By fitting the experimental data with a microscopic quantum theory based on a quantum jump approach, we scrutinize the influence of pump power and confinement and find that phonon-mediated transitions are enhanced in the case of a confined structure, in which the modes split into a discrete set. By increasing the pump power beyond the condensation threshold, temporal coherence significantly improves in devices with increased spatial confinement, as revealed in the transition from thermal to coherent statistics of the emitted light. Postprint

The Facility for Rare Isotopes Beams (FRIB) at Michigan State University will use projectile fragmentation and induced in-flight fission of heavy-ion primary beams at energies of 200 MeV/u and higher and at a beam power of 400 kW to generate rare isotope beams for experiments in nuclear physics, nuclear astrophysics, and fundamental symmetries, as well as for societal needs. The Advanced Rare Isotope Separator (ARIS) has been designed as a three-stage fragment separator for the efficient collection and purification of the rare isotope beams of interest. A vertically bending preseparator (first stage) with production target and beam dump is fully integrated into a production target facility hot cell with remote handling. The new separator compresses the accepted momentum width of up to ±5% of the beam by a factor of three in the standard operational mode. Provisions for alternate operational modes for specific cases are included in the design. This preseparator is followed by two, horizontally-bending separator stages (second and third stages) utilizing the magnets from the existing A1900 fragment separator at the National Superconducting Cyclotron Laboratory (NSCL). These stages can alternatively be coupled to a single high-resolution separator stage, resulting in the flexibility to optimize the operation for different experiments, including momentum tagging and in-flight particle identification of rare isotope beams. The design of ARIS will be presented with an emphasis on beam physics characteristics, and anticipated operational modes will be described.

The authors would like to thank the State of Bavaria for financial support. HS acknowledges support from the The Icelandic Research Fund, grant No. 163082-051. TL thanks the MOE Academic Research Fund for support. We report on electrically and nonresonant optically induced switching in the bistable regime of an electrically pumped polariton laser. Electrical switching effects can be observed by adding controlled noise in the electrical pump of the system. Noise is expected to influence the hysteresis characteristics of a bistable device and determines its application robustness. We find that the hysteresis width decreases symmetrically with a linear dependency until we observe a quenching of the bistability at a certain noise level and the output of the system becomes monostable. Furthermore, we explore the possibility to switch between the two bistable branches by a nonresonant optical pulse. Our experimental findings can be described by a set of rate equations modeling the population dynamics with additional noise terms. Postprint Postprint

The authors would like to thank the State of Bavaria for financial support. SM and TL were supported by the NAP Start-Up grant M4081630 and MOE AcRF Tier 1 grant 2016-T1-001-084. We report on optical probing of the Coulomb interactions in an electrically driven exciton-polariton laser. By positioning a weak non-resonant Gaussian continuous wave-beam with a diameter of 2 μm inside an electrical condensate excited in a 20 μm diameter micropillar, we study a repulsion effect which is characteristic of the part-excitonic nature of the microcavity system in strong coupling. It manifests itself in a modified real space distribution of the emission pattern. Furthermore, polariton repulsion results in a continuous blueshift of the emission with increased power of the probe beam. A Gross-Pitaevskii equation approach based on modeling the electrical and optical potentials explains our experimental data. Postprint

The systematic study of fission fragment yields under different initial conditions provides a valuable experimental benchmark for fission models that aim to understand this complex decay channel and to predict reaction product yields. Inverse kinematics coupled to the use of a high-resolution spectrometer is shown to be a powerful tool to identify and measure the inclusive isotopic yields of fission fragments. In-flight fusion fission was used to produce secondary beams of neutron-rich isotopes in the collision of a 238U beam at 24 MeV/u with 9Be and 12C targets at GANIL using the LISE3 fragment-separator. Unique A,Z,q identification of fission products was attained with the dE-TKE-Brho-ToF measurement technique. Mass, and atomic number distributions are reported for the two reactions that show the importance of different reaction mechanisms for these two targets., Comment: 14 pages, 10 figures, 4 tables

This work was supported by the State of Bavaria. S.D.L. acknowledges support from a Royal Society Research Fellowship and from EPSRC Grant No. EP/M003183/1. The dipole coupling strength g between cavity photons and quantum well excitons determines the regime of light matter coupling in quantum well-microcavities. In the strong coupling regime, a reversible energy between exciton and cavity photon takes place, which leads to the formation of hybrid polaritonic resonances. If the coupling is further increased, a hybridization of different single exciton states emerges, which is referred to as the very strong coupling regime. In semiconductor quantum wells such a regime is predicted to manifest as a photon-mediated electron-hole coupling leading to different excitonic wave functions for the two polaritonic branches when the ratio of the coupling strength to exciton binding energy gEB/ approaches unity. Here, we verify experimentally the existence of this regime in magneto-optical measurements on a microcavity characterized by gEB/≈0.64, showing that the average electron-hole separation of the upper polariton is significantly increased compared to the bare quantum well exciton Bohr radius. This yields a diamagnetic shift around zero detuning that exceeds the shift of the lower polariton by one order of magnitude and the bare quantum well exciton diamagnetic shift by a factor of two. The lower polariton exhibits a diamagnetic shift smaller than expected from the coupling of a rigid exciton to the cavity mode which suggests more tightly bound electron-hole pairs than in the bare quantum well. Postprint

We show that, by monitoring the free carrier reservoir in a GaAs-based quantum well microcavity under nonresonant pulsed optical pumping, lasing supported by a fermionic reservoir (photon lasing) can be distinguished from lasing supported by a reservoir of bosons (polariton lasing). Carrier densities are probed by measuring the photocurrent between lateral contacts deposited directly on the quantum wells of a microcavity that are partially exposed by wet chemical etching. We identify two clear thresholds in the input-output characteristic of the photoluminescence signal which can be attributed to polariton and photon lasing, respectively. The power dependence of the probed photocurrent shows a distinct kink at the threshold power for photon lasing due to an increased radiative recombination of free carriers as stimulated emission into the cavity mode sets in. At the polariton lasing threshold, on the other hand, the nonlinear increase of the luminescence is caused by stimulated scattering of exciton polaritons to the ground state which do not contribute directly to the photocurrent., Copyright 2016 American Physical Society DOI: https://doi.org/10.1103/PhysRevLett.117.127401

The level structure of 30 S was studied at the NSCL by using neutron removal reactions with a radioactive 31 S beam. The γ -decay from excited states in 30 S was measured in a Ge-detector array. The results discussed for this work will reduce the uncertainties in the determination of the astrophysical 29 P(p, γ ) 30 S reaction rate under rp -process conditions.

The Super Separator Spectrometer S 3 is a major experimental system developed for SPIRAL2. It has been designed for physics experiments with very low cross sections by taking full advantage of the very high intensity stable beams to be produced by LINAG, the superconducting linear accelerator at GANIL. These intensities will open new opportunities in several physics domains using fusion evaporation reactions, principally: super-heavy and very heavy element properties, spectroscopy at and beyond the dripline, and isomer and ground-state properties. The common feature of these experiments is the requirement to separate very rare events from intense backgrounds. S 3 accomplishes this with a large acceptance, a high background rejection efficiency, and a physical mass separation. This article will present the technical specifications and optical constraints needed to achieve these physical goals. The optical layout of the spectrometer will be presented, focusing on technical elements of the target system, the superconducting multipole magnets used to correct high-order optical aberrations, the electric and magnetic dipoles, and the open multipole triplet used for primary beam rejection. The expected system performance will be presented for three experimental cases using 3 specific optical modes of the spectrometer.

History A 56-year-old man complain of chronic cough for 6 months without further clinical problems. The patient was otherwise in good health and showed only a moderate bronchial sound at the left ventral paracordial region. Investigations Thorax X-ray revealed an infiltrate in the lingula with segmental borders. The CT scan showed air bronchogramms and bilateral more small infiltrates. DIAGNOSIS, TREATMENT, CLINICAL COURSE: Bronchoscopic transbronchial biopsies revealed a BALT-lymphoma. A seven years old chest X-ray showed the lingual infiltrate in nearly the same extension as the current X-ray. Because of the disseminated manifestation, the slow course and the good performance status we did not start a palliative chemotherapy so far. Conclusion Any pulmonary infiltrate which looks like pneumonia must be given a definite diagnosis if there are no clinical signs of infection.

Extensive magnetic field map measurements have been done on a newly built superconducting quadrupole triplet with sextupole and octupole coils nested within every quadrupole. The magnetic field multipole composition and fringe field distributions have been analyzed and an improved parameterization of the field has been developed within the beam transport simulation framework. Parameter fits yielding standard deviations as low as 0.3% between measured and modeled values are reported here.

Radiation-induced pneumonitis is a familiar complication of breast cancer radiotherapy, whereas bronchiolitis obliterans with organizing pneumonia occurs extremely rarely after this treatment. Consequently, testing for BOOP is rarely included in differential diagnosis. This results in delayed diagnosis, so that treatment is ultimately commenced too late. The infiltrations are often located in the unirradiated lung, impeding diagnosis. The radiotherapy-induced BOOP-reaction that can also occur after typical radiation pneumonitis is illustrated by reference to a characteristic case report.

The authors would like to thank the State of Bavaria for financial support. I.A.S. acknowledges the support of FP7 IRSES project POLAPHEN. S.H. gratefully acknowledges support by the Royal Society and the Wolfson Foundation. A.V.K. acknowledges financial support from the Ministry of Education and Science of the Russian Federation (Contract No. 11.G34.31.0067 with SPbSU), and EU projects POLAPHEN, SPANGL4Q, and LIMACONA. We observe a bistability in an electrically driven polariton condensate, which is manifested by a memory dependent threshold characteristic. In contrast to the polariton bistabilities previously observed in resonantly optically pumped microcavities, our effect occurs under nonresonant electric pumping and is triggered by the current injection scheme. We explain the origin of the bistability by a dependence of the electron-hole tunneling lifetime on the carrier density in the embedded quantum wells. The field screening effect creates a positive feedback loop, which yields the bistable behavior of the condensate. We develop a rate-equation-based model which qualitatively explains the occurrence of the hysteresis under current injection, its reduction with increased magnetic field, and the absence of bistability under optical pumping. Publisher PDF

We establish a technology which allows for deep and tunable polariton trapping. Pronounced band structures with full gaps and condensation at high symmetry points is observed in square lattice arrangements of evanescently coupled potential traps.

This work was financially supported by the state of Bavaria, the bilateral project of the Deutsche Forschungsgemeinschaft (within the project LIEPOLATE) and the Polish Ministry of Science and higher education (Project No. DPN/N99/DFG/2010) and the EU within the project SPANGL4Q. We report on electro optical tuning of the emission from GaAs quantum wells resonantly coupled to a Tamm-plasmon mode in a hybrid metal/dielectric structure. The structures were studied via momentum resolved photoluminescence and photoreflectance spectroscopy, and the surface metal layer was used as a top gate, which allowed for a precise tuning of the quantum well emission via the quantum confined Stark effect. By tuning the resonance, we were able to observe the characteristic anticrossing behavior of a polaritonic emission in the strong light-matter coupling regime, yielding a Rabi splitting of (9.2 ± 0.2) meV. Publisher PDF

Exciton-polariton lasers are operated in the strong light matter coupling regime. They promise low threshold operation since population inversion is not inherently necessary. Hence they are of great interest for next generation coherent light sources.

M. D. and A. V. K. acknowledge support from the Russian Ministry of Science and Education (Contract No. 11.G34.31.0067). A. V. C. acknowledges support from the Russian Foundation for Basic Research. We observe a strong variation of the Zeeman splitting of exciton polaritons in microcavities when switching between the linear regime, the polariton lasing, and photon lasing regimes. In the polariton lasing regime the sign of Zeeman splitting changes compared to the linear regime, while in the photon lasing regime the splitting vanishes. We additionally observe an increase of the diamagnetic shift in the polariton lasing regime. These effects are explained in terms of the nonequilibrium "spin Meissner effect." Publisher PDF

Background: Intestinal bleeding of unknown origin can lead to a difficult workup. Abdominal colic, melena/hematemesis, and jaundice represent the pathognomonic triad for hemobilia, but clinical presentation and etiology of this entity are varying. Seldom all of these symptoms are present, and rarely does hemobilia cause melena or hematemesis. Often the correct diagnosis is missed. Patients frequently have a long history of complaints and inadequate therapy. Case Report: We report on a patient who complained of repeated, severe epigastric pain and massive melena induced by exercise activity. After 2 years of complaints and an unnecessary operation, ultrasound detected a liver hemangioma. It was supposed that the hemangioma was causing hemobilia during strenuous physical activity. The patient underwent a partial liver resection to eliminate the hemangioma. All complaints resolved, and the patient remained asymptomatic postoperatively. Conclusions: Physicians should be aware of hemobilia as a rare cause of upper gastrointestinal bleeding, especially if esophagogastroduodenoscopy cannot demonstrate any bleeding source. Ultrasound is able to visualize many diseases leading to hemobilia and should be integrated into the early workup of unclear intestinal bleedings.

Pulmonary drug reactions are a relative common factor causing interstitial pulmonary diseases. The correct diagnosis is important since a causal therapy is possible by stopping the administration. A stringent correlation between dose/time of administration and the type of the reaction exists for only a few drugs. Possible hints for an increased risk to develop a drug reaction are known reactions to that specific drug, the patient's history, the type of the underlying disease, genetic poly-morphisms, occupational factors and interactions with other drugs. Still however, the tracing of a certain drug as cause of a pulmonary reaction can be difficult in the individual case and may require great efforts rarely even a biopsy. The pathologist then has to describe the patterns of reactions, exclude other causes and correlate his findings with the clinical data. In most cases however the diagnosis of a drug reaction will be by exclusion. A list of typical drug reactions is included.

Following a notice in the journal Deutsches Arzteblatt from July 2007 on the case of a 61 -year-old woman, who suffered fatal respiratory failure following intake of nitrofurantoin we report a case from the Zusamklinik. A 73-year-old woman had been suffering from coughing and dyspnea for six months. Due to a chronic infection of the bladder she had taken 100 mg of nitrofurantoin daily for one year. Fine endinspiratory crackles on both sides of her lungs could be heard, the lung function showed a restrictive lung disorder and a serious respiratory insufficiency. Transaminases and ANA were increased. On the conventional chest X-ray and the CT-thorax infiltrates on both sides and also small pleural effusions appeared. In a transbronchial lung biopsy a BOOP-reaction was histologically confirmed, the BAL showed 37% lymphocytes. Under treatment with steroids the patient's condition, the respiratory insufficiency, the X-ray findings and the transaminases improved. After administration of steroids for ten months, a complete reconstitution was achieved. Twelve months later, even without steroids, no symptoms occurred. Because of the history and the other findings a hypersensitive pneumonitis in combination with a drug-induced hepatitis is the most likely diagnosis, a drug-induced lupus erythematosus, however, is also possible.

History and admission findings A 26-year-old woman was admitted because of excessive weight loss: her body mass index was 11.3 kg/m (2). She reported an adequate food intake and denied fear of gaining weight. Investigations The leukocyte count on admission was 2.0/nl. Bone marrow biopsy showed gelatinous bone marrow transformation with hypocellularity. Psychiatric examination and observation of the patient's eating behavior revealed symptoms typical of anorexia nervosa. Diagnosis, treatment and course Because of the diagnosis of anorexia nervosa behaviour therapy was started. During the following months the patient continually gained weight. But it took nine months for leukocyte count to be normal, by which time her body mass index had risen to 17.8 kg/m (2). Conclusion Severe weight loss in anorexia nervosa may lead to leukopenia and gelatinous bone marrow transformation. The abnormal leukocyte count can become normal by maintaining body weight within the normal range.

A fundamental question in nuclear physics is what combinations of neutrons and protons can make up a nucleus. Many hundreds of exotic neutron-rich isotopes have never been observed; the limit of how many neutrons a given number of protons can bind is unknown for all but the lightest elements, owing to the delicate interplay between single particle and collective quantum effects in the nucleus. This limit, known as the neutron drip line, provides a benchmark for models of the atomic nucleus. Here we report a significant advance in the determination of this limit: the discovery of two new neutron-rich isotopes--40Mg and 42Al--that are predicted to be drip-line nuclei. In the past, several attempts to observe 40Mg were unsuccessful; moreover, the observation of 42Al provides an experimental indication that the neutron drip line may be located further towards heavier isotopes in this mass region than is currently believed. In stable nuclei, attractive pairing forces enhance the stability of isotopes with even numbers of protons and neutrons. In contrast, the present work shows that nuclei at the drip line gain stability from an unpaired proton, which narrows the shell gaps and provides the opportunity to bind many more neutrons.

We present a diode incorporating a large number (12) of GaAs quantum wells that emits light from exciton-polariton states at room temperature. A reversely biased tunnel junction is placed in the cavity region to improve current injection into the device. Electroluminescence studies reveal two polariton branches which are spectrally separated by a Rabi splitting of 6.5 meV. We observe an anticrossing of the two branches when the temperature is lowered below room temperature as well as a Stark shift of both branches in a bias dependent photoluminescence measurement.

Exciton-polariton lasers are operated in the strong light matter coupling regime. They promise low threshold operation since population inversion is not inherently necessary. Hence they are of great interest for next generation coherent light sources. Published version

Despite their name polariton lasers do not rely on stimulated emission of cavity photons. The less stringent threshold conditions are the cause that bosonic polariton lasers can outperform standard lasers in terms of their threshold currents. The part-light and part-matter quasiparticles called polaritons, can undergo a condensation process into a common energy state. The radiated light from such a system shares many similarities with the light emitted from a conventional photon laser, even though the decay of the polaritons out of the finite lifetime cavity is a spontaneous process. We discuss properties of polariton condensates in GaAs based microcavities. The system’s response to an external magnetic field is used as a reliable tool to distinguish between polariton laser and conventional photon laser. In particular, we will discuss the realization of an electrically pumped polariton laser, which manifests a major step towards the exploitation of polaritonic devices in the real world. Published version

Expérience GANIL/VAMOS/LISE; International audience; Two fission experiments have been performed at GANIL using 238U beams at different energies and light targets. Different fissioning systems were produced with centre of mass energies from 10 to 240MeV and their decay by fission was investigated with GANIL spectrometers. Fission-fragment isotopic distributions have been obtained. The evolution with impinging energy of their properties, the neutron excess and the width of the neutron-number distributions, gives important insights into the dynamics of the fusionfission mechanism.

Production cross sections for neutron-rich nuclei from the fragmentation of a ${}^{82}$Se beam at 139 MeV/u were measured. The longitudinal momentum distributions of 126 neutron-rich isotopes of elements $11\ensuremath{\le}Z\ensuremath{\le}32$ were scanned using an experimental approach of varying the target thickness. Production cross sections with beryllium and tungsten targets were determined for a large number of nuclei including several isotopes first observed in this work. These are the most neutron-rich nuclides of the elements $22\ensuremath{\le}Z\ensuremath{\le}25$ (${}^{64}$Ti, ${}^{67}$V, ${}^{69}$Cr, and ${}^{72}$Mn). One event was registered consistent with ${}^{70}$Cr and another one with ${}^{75}$Fe. The production cross sections are correlated with ${Q}_{g}$ systematics to reveal trends in the data. The results presented here confirm our previous results from a similar measurement using a ${}^{76}$Ge beam and can be explained with a shell model that predicts a subshell closure at $N=34$ around $Z=20$. This is demonstrated by systematic trends and calculations with the abrasion-ablation model that are sensitive to separation energies.

We report on the formation of spatially confined exciton-polaritons under electrical injection in a textured microcavity. The trapping of polaritons in the diode sample is achieved through a locally elongated GaAs microcavity with a quality factor exceeding 6000. The polaritonic resonances of traps with diameters of 10 mu m and 2 mu m are studied by angular-resolved electroluminescence spectroscopy, revealing their hybrid light-matter nature. Publisher PDF

We present the ground state lasing from zero dimensional lower polariton in the subwavelength grating (SWG) based microcavity. We also report diamagnetic shift and second order coherence of the ground state while it is lasing.

A new type of electrically pumped semiconductor laser has been demonstrated which promises an energy efficient laser operation: Recent achievements in the field of ‘polariton-laser’ development are presented and an outlook is given.

X-ray bursts are thermonuclear flashes on the surface of accreting neutron stars and reliable burst models are needed to interpret observations in terms of properties of the neutron star and the binary system. We investigate the dependence of X-ray burst models on uncertainties in (p,$\gamma$), ($\alpha$,$\gamma$), and ($\alpha$,p) nuclear reaction rates using fully self-consistent burst models that account for the feedbacks between changes in nuclear energy generation and changes in astrophysical conditions. A two-step approach first identified sensitive nuclear reaction rates in a single-zone model with ignition conditions chosen to match calculations with a state-of-the-art 1D multi-zone model based on the {\Kepler} stellar evolution code. All relevant reaction rates on neutron deficient isotopes up to mass 106 were individually varied by a factor of 100 up and down. Calculations of the 84 highest impact reaction rate changes were then repeated in the 1D multi-zone model. We find a number of uncertain reaction rates that affect predictions of light curves and burst ashes significantly. The results provide insights into the nuclear processes that shape X-ray burst observables and guidance for future nuclear physics work to reduce nuclear uncertainties in X-ray burst models., Comment: 24 pages, 13 figures, 4 tables, submitted

We report on pump-power-dependent emission features of a nonthermalized and interacting dynamical condensate of exciton polaritons. The system based on a planar AlAs/AlGaAs microcavity sample with twelve GaAs quantum wells in the active region is investigated comprehensively by measuring the energy-momentum dispersion characteristics, the spatial coherence, and the photon statistics under resonant, fs-pulsed optical excitation at high momentum. We observe a significant polariton-population-dependent modification of the emission signatures above the quantum degeneracy. The nonequilibrium polariton condensate is confirmed by its polaritonic energy-momentum dispersion as well as excitation-power-dependent coherence properties and its photon statistics, being different from that of an ideal coherent state. The polaritonic condensate is characterized by a spatial coherence length of up to 4 \ensuremath{\mu}m and a super-Poissonian photon statistic of the emitted light well above threshold. Results obtained in second-order photon autocorrelation measurements in momentum-space resolved spectroscopy indicate polariton repulsive interaction throughout the condensate and a spatial coherence length being shorter than the condensate extension of 20--30 \ensuremath{\mu}m.

Production cross sections for neutron-rich nuclei from the fragmentation of a 82Se beam at 139 MeV/u were measured. The longitudinal momentum distributions of 122 neutron-rich isotopes of elements $11 \le Z \le 32$ were determined by varying the target thickness. Production cross sections with beryllium and tungsten targets were determined for a large number of nuclei including several isotopes first observed in this work. These are the most neutron-rich nuclides of the elements $22 \le Z \le 25$ (64Ti, 67V, 69Cr, 72Mn). One event was registered consistent with 70Cr, and another one with 75Fe. A one-body Qg systematics is used to describe the production cross sections based on thermal evaporation from excited prefragments. The current results confirm those of our previous experiment with a 76Ge beam: enhanced production cross sections for neutron-rich fragments near Z=20., Talk given at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS)

Beta-delayed proton emission from nuclides in the neighborhood of 100Sn was studied at the National Superconducting Cyclotron Laboratory. The nuclei were produced by fragmentation of a 120 MeV/nucleon 112Sn primary beam on a Be target. Beam purification was provided by the A1900 Fragment Separator and the Radio Frequency Fragment Separator. The fragments of interest were identified and their decay was studied with the NSCL Beta Counting System (BCS) in conjunction with the Segmented Germanium Array (SeGA). The nuclei 96Cd, 98Ing, 98Inm and 99In were identified as beta-delayed proton emitters, with branching ratios bp = 5.5(40)%, 5.5+3 -2%, 19(2)% and 0.9(4)%, respectively. The bp for 89Ru, 91,92Rh, 93Pd and 95Ag were deduced for the first time with bp = 3+1.9 -1.7%, 1.3(5)%, 1.9(1)%, 7.5(5)% and 2.5(3)%, respectively. The bp = 22(1)% for 101Sn was deduced with higher precision than previously reported. The impact of the newly measured bp values on the composition of the type-I X-ray burst ashes was studied.

During the fission process, the nucleus deforms and elongates up to the two fragments inception and their final separation at scission deformation. The evolution of the nucleus energy with deformation is determined by the macroscopic properties of the nucleus, and is also strongly influenced by the single-particle structure of the nucleus. The fission fragment distribution is a direct consequence of the deformation path the nucleus has encountered, and therefore is the most genuine experimental observation of the potential energy landscape of the deforming nucleus. Very asymmetric fusion-fission reactions at energy close to the Coulomb barrier, produce well-defined conditions of the compound nucleus formation, where processes such as quasi-fission, pre-equilibrium emission and incomplete fusion are negligible. In the same time, the excitation energy is sufficient to reduce significantly structural effects, and mostly the macroscopic part of the potential is responsible for the formation of the fission fragments. We use inverse kinematics combined with spectrometers to select and identify the fission fragments produced in $^{238}$U+$^{12}$C at a bombarding energy close to and well-above the Coulomb barrier. For the first time, the isotopic yields are measured over the complete atomic-number distribution, between Z=30 and Z=63. The experimental set-up also allows to identify transfer-induced reactions, which lead to low-energy fission where the nuclear shell structure shows a strong influence on the fission-fragment distributions. The resulting set of data gives the possibility to observe the fission fragment properties over a wide range of excitation energy, and they reveal the vanishing of the shell effects in the potential energy of the fissioning nucleus, as well as the influence of fission dynamics., Comment: Invited Plenary Talk given at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS)

Expérience GANIL/VAMOS-LISE; International audience; Two fission experiments have been performed at GANIL using 238U beams at different energies and light targets. Different fissioning systems were produced with excitation energies from 10 to 230 MeV and their decay by fission was investigated with GANIL spectrometers. Preliminary fission-fragment isotopic distributions have been obtained. The evolution with impinging energy of their properties, the neutron excess and the width of the neutron-number distributions, gives important insights into the dynamics of fusion-fission mechanism.