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We demonstrate a new technique for obtaining fission data for nuclei away from β stability. These types of data are pertinent to the astrophysical r process, crucial to a complete understanding of the origin of the heavy elements, and for developing a predictive model of fission. These data are also important considerations for terrestrial applications related to power generation and safeguarding. Experimentally, such data are scarce due to the difficulties in producing the actinide targets of interest. The solenoidal-spectrometer technique, commonly used to study nucleon-transfer reactions in inverse kinematics, has been applied to the case of transfer-induced fission as a means to deduce the fission-barrier height, among other variables. The fission-barrier height of U239 has been determined via the U238(d,pf) reaction in inverse kinematics, the results of which are consistent with existing neutron-induced fission data indicating the validity of the technique. We demonstrate a new technique for obtaining fission data for nuclei away from $\beta$-stability. These types of data are pertinent to the astrophysical \textit{r-}process, crucial to a complete understanding of the origin of the heavy elements, and for developing a predictive model of fission. These data are also important considerations for terrestrial applications related to power generation and safeguarding. Experimentally, such data are scarce due to the difficulties in producing the actinide targets of interest. The solenoidal-spectrometer technique, commonly used to study nucleon-transfer reactions in inverse kinematics, has been applied to the case of transfer-induced fission as a means to deduce the fission-barrier height, among other variables. The fission-barrier height of $^{239}$U has been determined via the $^{238}$U($d$,$pf$) reaction in inverse kinematics, the results of which are consistent with existing neutron-induced fission data indicating the validity of the technique.

The occupancies and vacancies of the valence neutron orbitals across the stable tin isotopic chain from $112\leq A\leq 124$ have been determined. These were inferred from the cross sections of neutron-adding and -removing reactions. In each case, the reactions were chosen to have good angular-momentum matching for transfer to the low- and high-$\ell$ orbitals present in this valence space. These new data are compared to older systematic studies. The effective single-neutron energies are determined by combining information from energy centroids determined from the adding and removing reactions. Two of the five orbitals are nearly degenerate, below $N=64$, and approximately two MeV more bound than the other three, which are also degenerate., Comment: 11 pages, 10 figures

Nucleon-transfer sum rules have been assessed via a consistent reanalysis of cross-section data from neutron-adding ($d$,$p$) and -removing ($d$,$t$) reactions on well-deformed isotopes of Gd, Dy, Er, Yb, and W, with $92\leq N\leq108$, studied at the Niels Bohr Institute in the 1960s and 1970s. These are complemented by new measurements of cross sections using the ($d$,$p$), ($d$,$t$), and ($p$,$d$) reactions on a subset of these nuclei. The sum rules, defined in a Nilsson-model framework, are remarkably consistent. A single overall normalization is used in the analysis, which appears to be sensitive to assumptions about the reaction mechanism, and in the case of sums using the ($d$,$t$) reaction, differs from values determined from reactions on spherical systems., 7 pages, 4 figures

A systematic study of neutron-hole strength in the N = 81 nuclei 137Ba, 139Ce, 141Nd and 143Sm is reported. The single-neutron removal reactions (p,d) and (3He,) were measured at energies of 23 and 34 MeV, respectively. Spectroscopic factors were extracted from measured cross sectionsthrough a distorted-wave Born approximation analysis and centroids of single-particle strength have been established. The change in these centroid energies as a function of proton number have been compared to calculations of the monopole shift for the s1=2 and h11=2 orbitals, where the majorityof the strength has been observed. Signicant fragmentation of strength was observed for the d and g7=2 orbitals, particularly for the latter orbital which is deeply bound, with summed strengths that indicate a signicant amount lies outside of the measured excitation energy range.

The nuclei below lead but with more than 126 neutrons are crucial to an understanding of the astrophysical r process in producing nuclei heavier than A∼190. Despite their importance, the structure and properties of these nuclei remain experimentally untested as they are difficult to produce in nuclear reactions with stable beams. In a first exploration of the shell structure of this region, neutron excitations in ^{207}Hg have been probed using the neutron-adding (d,p) reaction in inverse kinematics. The radioactive beam of ^{206}Hg was delivered to the new ISOLDE Solenoidal Spectrometer at an energy above the Coulomb barrier. The spectroscopy of ^{207}Hg marks a first step in improving our understanding of the relevant structural properties of nuclei involved in a key part of the path of the r process. ispartof: Physical Review Letters vol:124 issue:6 ispartof: location:United States status: published

The pairing properties of the neutrinoless double-$\beta$ decay candidate $^{116}$Cd have been investigated. Measurements of the two-neutron removal reactions on isotopes of $^{114,116}$Cd have been made in order to identify 0$^+$ strength in the residual nuclei up to $\approx$3 MeV. No significant $L=0$ strength has been found in excited states indicating that the Bardeen-Cooper-Schrieffer (BCS) approximation is a reasonable basis to describe the neutrons in the ground state. This approximation avoids complications in calculations of double-$\beta$ decay matrix elements that use the quasiparticle random-phase approximation (QRPA) techniques. However this is not the case for the protons, where pair vibrations are prevalent and the BCS approximation is no longer valid, complicating the use of traditional QRPA techniques for this system as a whole.

Excited states in the neutron-rich 70 Fe nucleus were populated in a one-proton removal reaction from 71 Co projectiles at 87 MeV/nucleon. A new transition was observed with the γ -ray tracking array GRETINA and shown to feed the previously assigned 4+ 1 state. In comparison to reaction theory calculations with shell-model spectroscopic factors, it is argued that the new γ ray possibly originates from the 6+ 1 state. It is further shown that the Doppler-reconstructed γ -ray spectra are sensitive to the very different lifetimes of the 2+ and 4+ states, enabling their approximate measurement. The emerging structure of 70 Fe is discussed in comparison to LNPS-new large-scale shell-model calculations.

The neutron-deficient mercury isotopes serve as a classical example of shape coexistence, whereby at low energy near-degenerate nuclear states characterized by different shapes appear. The electromagnetic structure of even-mass 182-188 Hg isotopes was studied using safe-energy Coulomb excitation of neutron-deficient mercury beams delivered by the REX-ISOLDE facility at CERN. The population of $ 0^{+}_{1,2}$01,2+, $ 2^{+}_{1,2}$21,2+and $ 4^{+}_{1}$41+states was observed in all nuclei under study. Reduced E2 matrix elements coupling populated yrast and non-yrast states were extracted, including their relative signs. These are a sensitive probe of shape coexistence and may be used to validate nuclear models. The experimental results are discussed in terms of mixing of two different configurations and are compared with three different model calculations: the Beyond Mean Field model, the Interacting Boson Model with configuration mixing and the General Bohr Hamiltonian. Partial agreement with experiment was observed, hinting to missing ingredients in the theoretical descriptions. The neutron-deficient mercury isotopes serve as a classical example of shape coexistence, whereby at low energy near-degenerate nuclear states characterized by different shapes appear. The electromagnetic structure of even-mass 182-188 Hg isotopes was studied using safe-energy Coulomb excitation of neutron-deficient mercury beams delivered by the REX-ISOLDE facility at CERN. The population of $ 0^{+}_{1,2}$01,2+, $ 2^{+}_{1,2}$21,2+and $ 4^{+}_{1}$41+states was observed in all nuclei under study. Reduced E2 matrix elements coupling populated yrast and non-yrast states were extracted, including their relative signs. These are a sensitive probe of shape coexistence and may be used to validate nuclear models. The experimental results are discussed in terms of mixing of two different configurations and are compared with three different model calculations: the Beyond Mean Field model, the Interacting Boson Model with configuration mixing and the General Bohr Hamiltonian. Partial agreement with experiment was observed, hinting to missing ingredients in the theoretical descriptions. ispartof: The European Physical Journal A - Hadrons and Nuclei vol:55 issue:8 pages:130-130 status: published

International audience; Excited states of the rubidium isotopes$_{37}^{87, 89, 91}$Rb have been studied at the INFN Legnaro National Laboratory. Measurements of the $\gamma$ -ray decay of fragments produced in binary grazing reactions resulting from the interaction of a beam of 530 MeV$^{96}$Zr ions with a$^{124}$Sn target have been complemented by studies of the $\gamma$ -ray decay of fission fragments produced in the interaction of a beam of 230 MeV$^{36}$S ions with a thick$^{176}$Yb target. The structure of the yrast states of$_{37}^{87, 89, 91}$Rb has been discussed within the context of spherical shell-model and cranked Nilsson-Strutinsky calculations.

The energy levels and γ-ray decay scheme of the positive-parity states in the Tz=12 nucleus As67 have been studied by using the Ca40(Ar36,2αp)As67 reaction at a beam energy of 145 MeV. Two new band structures have been identified which can be connected to the previously known levels. The results for these bands are compared with configuration-dependent cranked Nilsson-Strutinsky calculations. The good level of agreement between theory and experiment suggests that these structures can be interpreted in terms of configurations that involve three g92 particles and that both possess noncollective terminating states.

Introduction Simulation is increasingly used throughout medicine. Within ultrasound, simulators are more established for learning transvaginal and interventional procedures. The use of modern high-fidelity transabdominal simulators is increasing, particularly in centres with large trainee numbers. There is no current literature on the value of these simulators in gaining competence in abdominal ultrasound. The aim was to investigate the impact of a new ultrasound curriculum, incorporating transabdominal simulators into the first year of training in a UK radiology academy. Methods The simulator group included 13 trainees. The preceding cohort of 15 trainees was the control group. After 10 months, a clinical assessment was performed to assess whether the new curriculum resulted in improved ultrasound skills. Questionnaires were designed to explore the acceptability of simulation training and whether it had any impact on confidence levels. Results Trainees who had received simulator-enriched training scored higher in an objective clinical ultrasound assessment, which was statistically significant ( p = 0.0463). End confidence scores for obtaining diagnostic images and demonstrating pathology were also higher in the simulation group. All trainees stated that transabdominal simulator training was useful in early training. Conclusions This initial study shows that embedded into a curriculum, transabdominal ultrasound simulators are an acceptable training method that can result in improved ultrasound skills and higher confidence levels. Using simulators early in training could allow trainees to master the basics, improve their confidence, enabling them to get more educational value from clinical ultrasound experience while reducing the impact of training on service provision.

The rearrangements of protons and neutrons amongst the valence single-particle orbitals during double-$\ensuremath{\beta}$ decay of $^{100}\mathrm{Mo}$ have been determined by measuring cross sections in ($d,p$), ($p,d$), ($^{3}\mathrm{He},\ensuremath{\alpha}$), and ($^{3}\mathrm{He},d$) reactions on $^{98,100}\mathrm{Mo}$ and $^{100,102}\mathrm{Ru}$ targets. The deduced nucleon occupancies reveal significant discrepancies when compared with theoretical calculations; the same calculations have previously been used to determine the nuclear matrix element associated with the decay probability of double-$\ensuremath{\beta}$ decay of the $^{100}\mathrm{Mo}$ system.

The high-spin structures of the N = 81 isotones 135Xe and 137Ba are investigated after multinucleontransfer (MNT) and fusion-evaporation reactions. Both nuclei are populated in (i) 136Xe+238U and (ii) 136Xe+208Pb MNT reactions employing the high-resolution Advanced Gamma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA, (iii), in the 136Xe+198Pt MNT reaction employing the -ray array GAMMASPHERE in combination with the gas detector array Chico, and (iv) via a 11B+130Te fusion-evaporation reaction. The high-spin level schemes of 135Xe and 137Ba are considerably extended to higher energies. The 2058-keV (19=2 ) state in 135Xe is identified as an isomer, completing the systematics for the N = 81 isotones. Its half-life is measured to be 8.6(10) ns, corresponding to a transition probability of B(E2; 19=2 ! 15=2 ) = 0:539(69) W.u. Latest shell model calculations considering 132Sn as a closed core reproduce the experimental findings and provide guidance to the interpretation of the new levels. The experimentally deduced reduced quadrupole transition probabilities of the isomeric states are compared to shell-model predictions.

Multi-quasiparticle high-K states, several of which are isomeric, were observed in Hf-180 with the Gammasphere array. We determined the lifetimes in the ns-μs range using centroid-shift and decay measurements within a mu s coincidence time window. The configurations of high-K states involve two and four quasiparticles, with states up to Kπ = (18-) established. High-K excitations are found to be progressively more favored with increasing excitation energy. The K quantum number is quite robust up to the highest spins observed, as evidenced by the large values of the reduced hindrance for isomeric decays. Furthermore, rotational bands built on three high-K states are identified, and the measured branching ratios in these sequences enable the assignment of underlying configurations. Multi-quasiparticle calculations using the Lipkin-Nogami approach for pairing, with blocking included, reproduce the observed high-K energies quite well.

Objectives To compare image quality on computed tomographic (CT) images acquired with filtered back-projection (FBP), adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) techniques in CT kidney/ureter/bladder (KUB) examination. Methods Eighteen patients underwent standard protocol CT KUB at our institution. The same raw data were reconstructed using FBP, ASIR and MBIR. Objective [mean image noise, contrast-to-noise ratio (CNR) for kidney and mean attenuation values of subcutaneous fat] and subjective image parameters (image noise, image contrast, overall visibility of kidneys/ureters/bladder, visibility of small structures, and overall diagnostic confidence) were assessed using a scoring system from 1 (best) to 5 (worst). Results Objective image measurements revealed significantly less image noise and higher CNR and the same fat attenuation values for the MBIR technique (P 0.05), while there was a significant difference between ASIR vs. MBIR (P

In neutrinoless double-$\ensuremath{\beta}$ decay such as ${}^{136}$Xe to ${}^{136}$Ba, two neutrons become two protons, thus rearranging the occupancy of protons and neutrons in the ground states of the parent and daughter nuclei. From precision measurements of the cross sections of single-neutron adding and -removing reactions, the authors extract the change in ground-state neutron occupancies between ${}^{136}$Xe and ${}^{136}$Ba. Along with recent results on the proton occupancies, the new experimental neutron occupancies disagree with those used in existing theoretical calculations of the rate of this elusive $\ensuremath{\beta}$-decay mode, and provide a \hskip-0.22em \hskip-0.22embasis for improved estimates of the uncertainties for new calculations.

The change in the configuration of valence protons between the initial and final states in the neutrinoless double-$\beta$ decay of $^{130}$Te $\rightarrow$ $^{130}$Xe and of $^{136}$Xe $\rightarrow$ $^{136}$Ba has been determined by measuring the cross sections of the ($d$,$^3$He) reaction with 101-MeV deuterons. Together with our recent determination of the relevant neutron configurations involved in the process, a quantitative comparison with the latest shell-model and interacting-boson-model calculations reveals significant discrepancies. These are the same calculations used to determine the nuclear matrix elements governing the rate of neutrinoless double-$\beta$ decay in these systems.

Acta physica Polonica / B 47(3), 627 - 636(2016). doi:10.5506/APhysPolB.47.627, Published by Inst. of Physics, Jagellonian Univ., Cracow

© 2015 Elsevier B.V. It is planned to install the heavy-ion, low-energy ring TSR, currently at the Max-Planck-Institute for Nuclear Physics in Heidelberg, at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored, cooled secondary beams that is rich and varied, spanning from studies of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. In addition to experiments performed using beams recirculating within the ring, the cooled beams can be extracted and exploited by external spectrometers for high-precision measurements. The capabilities of the ring facility as well as some physics cases will be presented, together with a brief report on the status of the project. ispartof: Nuclear Instruments & Methods in Physics Research B vol:376 pages:270-274 ispartof: location:Grand Rapids: MI status: published

A. Vogt et al. ; 12 págs.; 9 figs.; 1 tab., Detailed spectroscopic information on the N∼82 nuclei is necessary to benchmark shell-model calculations in the region. The nuclear structure above long-lived isomers in Xe134 is investigated after multinucleon transfer (MNT) and actinide fission. Xenon-134 was populated as (i) a transfer product in Xe136+U238 and Xe136+Pb208 MNT reactions and (ii) as a fission product in the Xe136+U238 reaction employing the high-resolution Advanced Gamma Tracking Array (AGATA). Trajectory reconstruction has been applied for the complete identification of beamlike transfer products with the magnetic spectrometer PRISMA. The Xe136+Pt198 MNT reaction was studied with the γ-ray spectrometer GAMMASPHERE in combination with the gas detector array Compact Heavy Ion Counter (CHICO). Several high-spin states in Xe134 on top of the two long-lived isomers are discovered based on γγ-coincidence relationships and information on the γ-ray angular distributions as well as excitation energies from the total kinetic energy loss and fission fragments. The revised level scheme of Xe134 is extended up to an excitation energy of 5.832 MeV with tentative spin-parity assignments up to 16+. Previous assignments of states above the 7- isomer are revised. Latest shell-model calculations employing two different effective interactions reproduce the experimental findings and support the new spin and parity assignments., The research leading to these results has received funding from the German BMBF under Contract No. 05P12PKFNE TP4, from the European Union Seventh Framework Programme FP7/2007–2013 under Grant Agreement No. 262010 - ENSAR, from the Spanish Ministerio de Ciencia e Innovación under Contract No. FPA2011-29854-C04, from the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2014-57196-C5, from the Bonn-Cologne Graduate School of Physics and Astronomy (BCGS), from the UK Science and Technology Facilities Council (STFC), and from the US National Science Foundation (NSF). One of the authors (A. Gadea) has been supported by the Generalitat Valenciana, Spain, under Grant No. PROMETEOII/2014/019 and EU under the FEDER program.

Background: Neutron-rich, even-mass chromium and iron isotopes approaching neutron number $N=40$ have been important benchmarks in the development of shell-model effective interactions incorporating the effects of shell evolution in the exotic regime. Odd-mass manganese nuclei have received less attention, but provide important and complementary sensitivity to these interactions.Purpose: We report the observation of two new $\ensuremath{\gamma}$-ray transitions in $^{63}\mathrm{Mn}$, which establish the $(9/{2}^{\ensuremath{-}})$ and $(11/{2}^{\ensuremath{-}})$ levels on top of the previously known $(7/{2}^{\ensuremath{-}})$ first-excited state. The lifetime for the $(7/{2}^{\ensuremath{-}})$ and $(9/{2}^{\ensuremath{-}})$ excited states were determined for the first time, while an upper limit could be established for the $(11/{2}^{\ensuremath{-}})$ level.Method: Excited states in $^{63}\mathrm{Mn}$ have been populated in inelastic scattering from a $^{9}\mathrm{Be}$ target and in the fragmentation of $^{65}\mathrm{Fe}$. $\ensuremath{\gamma}\ensuremath{\gamma}$ coincidence relationships were used to establish the decay level scheme. A Doppler line-shape analysis for the Doppler-broadened $(7/{2}^{\ensuremath{-}})\ensuremath{\rightarrow}5/{2}^{\ensuremath{-}}$, $(9/{2}^{\ensuremath{-}})\ensuremath{\rightarrow}(7/{2}^{\ensuremath{-}}),$ and $(11/{2}^{\ensuremath{-}})\ensuremath{\rightarrow}(9/{2}^{\ensuremath{-}})$ transitions was used to determine (limits for) the corresponding excited-state lifetimes.Results: The low-lying level scheme and the excited-state lifetimes were compared with large-scale shell-model calculations using different model spaces and effective interactions in order to isolate important aspects of shell evolution in this region of structural change.Conclusions: While the theoretical $(7/{2}^{\ensuremath{-}})$ and $(9/{2}^{\ensuremath{-}})$ excitation energies show little dependence on the model space, the calculated lifetime of the $(7/{2}^{\ensuremath{-}})$ level and calculated energy of the $(11/{2}^{\ensuremath{-}})$ level reveal the importance of including the neutron ${g}_{9/2}$ and ${d}_{5/2}$ orbitals in the model space. The LNPS effective shell-model interaction provides the best overall agreement with the new data.

Quasistatic strain imaging is a form of elastography that can produce qualitative images of tissue stiffness with only software modifications to conventional ultrasound hardware. Unlike current commercial offerings, the novel strain-imaging system that is the subject of this paper displays regions of signal decorrelation using an overlaid colour mask and can also produce three-dimensional (3D) strain images. In illustrative studies of the breast, testis and thyroid, the colour mask is seen to reduce the potential to misinterpret noise as meaningful stiffness information, and also helps to differentiate cystic and solid lesions. High-quality imaging of the testis in vivo demonstrates that 3D strain imaging is feasible.

Zhu, S. Janssens, R. V. F. Fornal, B. Freeman, S. J. Honma, M. Broda, R. Carpenter, M. P. Deacon, A. N. Kay, B. P. Kondev, F. G. Krolas, W. Kozemczak, J. Larabee, A. Lauritsen, T. Liddick, S. N. Lister, C. J. Mantica, P. F. Otsuka, T. Pawlat, T. Robinson, A. Seweryniak, D. Smith, J. F. Steppenbeck, D. Tomlin, B. E. Wrzesinski, J. Wang, X.

Background: Shape coexistence in heavy nuclei poses a strong challenge to state-of-the-art nuclear models, where several competing shape minima are found close to the ground state. A classic region for investigating this phenomenon is in the region around Z=82 and the neutron midshell at N=104. Purpose: Evidence for shape coexistence has been inferred from α-decay measurements, laser spectroscopy, and in-beam measurements. While the latter allow the pattern of excited states and rotational band structures to be mapped out, a detailed understanding of shape coexistence can only come from measurements of electromagnetic matrix elements. Method: Secondary, radioactive ion beams of Rn202 and Rn204 were studied by means of low-energy Coulomb excitation at the REX-ISOLDE in CERN. Results: The electric-quadrupole (E2) matrix element connecting the ground state and first excited 21+ state was extracted for both Rn202 and Rn204, corresponding to B(E2;21+→01+)=29-8+8 and 43-12+17 W.u. respectively. Additionally, E2 matrix elements connecting the 21+ state with the 41+ and 22+ states were determined in Rn202. No excited 0+ states were observed in the current data set, possibly owing to a limited population of second-order processes at the currently available beam energies. Conclusions: The results are discussed in terms of collectivity and the deformation of both nuclei studied is deduced to be weak, as expected from the low-lying level-energy schemes. Comparisons are also made to state-of-the-art beyond-mean-field model calculations and the magnitude of the transitional quadrupole moments are well reproduced., 0, SCOPUS: ar.j, info:eu-repo/semantics/published

Excited states up to I π = 8 + in the neutron-rich nucleus 58Cr have been identified by using a new experimental setup composed of the large acceptance magnetic spectrometer PRISMA and the highly efficient γ-detector array CLARA. Interestingly, the excitation energy sequence of the ground-state band follows the one expected by the E ( 5 ) dynamical symmetry for a nucleus at the critical point of the shape phase transition from a spherical vibrator ( U ( 5 ) ) to a γ-soft rotor ( O ( 6 ) ). For the first time, in the same physical system, large scale shell-model calculations in the full fp shell are compared to the E ( 5 ) analytical model results and to the Interacting Boson Model. The theoretical results are in excellent agreement with the present data.

Excited states have been identified in the very neutron-deficient 122Ce nucleus. This is the first observation of this nucleus and its excited states. The ground-state rotational band has been observed up to spin 14 ℏ. The band has been assigned to 122Ce by detecting gamma rays in coincidence with evaporated charged particles and neutrons. The E ( 2 1 + ) value suggests a rather large ground-state deformation of β 2 = 0.35 , in good agreement with Hartree–Fock–Bogoliubov (HFB) mean-field calculations. The aligned angular momentum of the band has been studied and is compared with those of the neighboring even–even cerium isotopes, and to Woods–Saxon cranking calculations. The non-observation of the π ( h 11 / 2 ) 2 alignment until at least 0.4 MeV/ℏ is consistent with the extracted value of β 2 .

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 νg9/2 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 g9/2 neutrons.

Excited states in 57 Cr have been populated to high spin in the C 14 ( Ca 48 , α n ) reaction at a beam energy of 130 MeV. A regular sequence of stretched quadrupole transitions has been established above the yrast 9 / 2 + level. This sequence is interpreted as a rotational band associated with prolate deformation induced by the excitation of the odd neutron into the 1 / 2 + [ 440 ] orbital. Total Routhian surface calculations, which follow this configuration to high spin, reproduce the observed features of the band. They are also able to account for a similar, but less well developed structure in 55 Cr. In contrast, the isomeric yrast 9 / 2 + state in 59 Cr appears to be a band-head state dominated by the 9 / 2 + [ 404 ] configuration, which is favoured at oblate deformations. Such a marked difference presents a significant challenge for theoretical descriptions, but is consistent with features exhibited by the low-lying negative-parity states in 59 Cr.

The fusion–evaporation reaction 10 B( 12 C, 2 n ) was used to make the first observation of in-beam γ decays from the astrophysically important nucleus 20 Na, lying adjacent to the proton drip-line. All states below the proton threshold in 20 Na were populated and identified in the experiment. These include new levels, previously unresolved levels, and states located with improved energy precision. The level structure of 20 Na, and its γ transitions, are compared to the mirror partner 20 F measured simultaneously in this experiment. In particular, a high degree of energy stability is found for all negative parity states. These results are discussed in the context of the nuclear shell model.

Long-lived high- K states have been identified in 177 Lu, including an isomer with τ >10 μs, placed at 3530 keV and associated with the yrast K π =39/2 − , 5-quasiparticle state predicted in multi-quasiparticle-state calculations. The γ -decay of the isomer exposes the rotational band based on the 160-day 23/2 − isomer, 177m Lu , with band properties which support its proposed configuration. A 90-ns isomer at 1325 keV is associated with the predicted 3-quasiparticle K π =25/2 + state while a 5-quasiparticle 33/2 + , 902-ns isomer with highly-hindered decays is identified at 2771 keV. Both exhibit rotational bands whose properties are used to support the assigned configurations. The possibility that the K π =39/2 − isomer found in this work should be identified with a β -decaying isomer, proposed recently to populate the 51-min 37/2 − isomer in 177 Hf, is discussed in terms of the implied log ft values, configuration changes, and hindrances for K -forbidden γ -decays.

Lifetime measurements have been performed for yrast rotational states of 100Zr and 104Mo using a 252Cf source in a differential plunger arrangement, together with the EUROBALL and SAPHIR multi-detector arrays. The system has been proved capable of covering a range of lifetimes from a nanosecond to a picosecond. The transition quadrupole moments are found to decrease by around 20% between I = 4 and I = 8 in the case of 104Mo while remaining constant in 100Zr. The origin of this effect lies either in a rotation-induced shape change, or in the strong mixing between the ground and s-bands in 104Mo.

High-spin states in the neutron-deficient isotope Cd-104 were populated using the Cr-50(Ni-58,4p)Cd-104 reaction at a beam energy of 250 MeV The level scheme has been extended using triple gamma-ray coincidences to a spin of 29h and an excitation energy of 18.2 MeV. Several collective structures involving the excitation of h(11/2) neutrons have been observed to spins approaching 30h. The high-spin structure has been compared to the results of cranked Nilsson-Strutinsky calculations.

A retrospective analysis of the clinical utility of (99m)Tc-dimercaptosuccinic acid (DMSA) single photon emission CT (SPECT) for characterization of suspected renal masses.15 patients who had undergone (99m)Tc-DMSA SPECT were identified, and 13 patients also had SPECT/CT. (99m)Tc-DMSA uptake in the renal lesion was characterized semiquantitatively. Other imaging tests, histology and clinical data were available for correlation.(99m)Tc-DMSA was not taken up in all five renal masses with histological confirmation of malignancy (uptake 7-19% of normal renal tissue); in two further masses, which were clinically likely to be malignant; and in one indeterminate mass (lack of sufficiently long follow-up). No renal malignancy was identified in any of the seven patients whose renal masses had normal (99m)Tc-DMSA uptake (41-130%).Although caution with regard to applying those results in clinical practice must be advised, owing to the retrospective nature of this report and the small number of patients included, it seems that (99m)Tc-DMSA SPECT shows a clinically useful diagnostic accuracy for distinguishing true renal masses (which in many cases require surgery) from pseudomasses.(99m)Tc-DMSA SPECT is a clinically useful adjunct test for characterization of suspected renal masses.

Coulomb-excitation experiments to study electromagnetic properties of radioactive even-even Hg isotopes were performed with 2.85 MeV/nucleon mercury beams from REX-ISOLDE. Magnitudes and relative signs of the reduced E2 matrix elements that couple the ground state and low-lying excited states in Hg182-188 were extracted. Information on the deformation of the ground and the first excited 0(+) states was deduced using the quadrupole sum rules approach. Results show that the ground state is slightly deformed and of oblate nature, while a larger deformation for the excited 0(+) state was noted in Hg-182; 184. The results are compared to beyond mean field and interacting-boson based models and interpreted within a two-state mixing model. Partial agreement with the model calculations was obtained. The presence of two different structures in the light even-mass mercury isotopes that coexist at low excitation energy is firmly established.

Excited states have been identified in the very neutron-deficient 112 Xe nucleus. The ground-state band has been observed up to spin 12 ℏ, and a negative-parity side band has been observed up to 13 ℏ. The bands have been assigned to 112 Xe by detecting gamma rays in coincidence with evaporated charged particles and neutrons. The energy of the 2 + 1 state in 112 Xe is lower than would be expected from both calculations and from systematics of the neighboring xenon isotopes, which indicates a larger than expected ground-state deformation. The observations of a low-lying 3 − state and large deduced B (E1) values are suggestive of increased octupole correlations, which may explain the apparently large ground-state deformation. Constrained Hartree–Fock+BCS calculations have been performed which show qualitative agreement with the trend in deformation of the very neutron-deficient xenon isotopes.

To establish whether there is a consensus regarding the significance of testicular microlithiasis and a strategy for managing patients with this condition, amongst ultrasound practitioners in the UK.An electronic questionnaire was distributed to 1482 members of the British Medical Ultrasound Society (BMUS), requesting information from ultrasound practitioners involved in scrotal ultrasound about their interpretation of the risk associated with testicular microlithiasis and their departmental or personal recommendations for managing patients with this condition.Responses were obtained from 221 BMUS members. Analysis demonstrated a wide variation in the significance attributed to the discovery of testicular microlithiasis and the risk of subsequent development of testicular germ cell tumours. There was also great variation in strategies for management of patients with testicular microlithiasis, including the need for surveillance ultrasound, amongst ultrasound practitioners regardless of their job description.Lack of consensus shown by this study highlights significant differences across the UK in managing patients with testicular microlithiasis and validates the importance of guidance currently being formulated by the European Society of Urogenital Radiology.We believe that this is the first survey to be conducted amongst imaging specialists in the UK regarding testicular microlithiasis and demonstrates that there is currently no uniform practice in managing patients with this condition.

Measurements of g-factors of excited states in barium and cerium fission fragments have been performed using time-integral perturbed angular correlations between secondary-fragment gamma rays. Larmor precession angles have been obtained for the first I-pi = 2(+) states in Ba-144,Ba-146 and Ce-146,Ce-148 as well as for the 9/2(-) state at 117 keV in Ba-143, the 7/2(-) state at 114 keV in Ba-145 and the first 4(+) state in Ce-150. The deduced g-factor fur the 2(+) state in Ba-146 provides substantiating evidence for a downward trend in 2(+) g-factors with increasing neutron number, in line with Interacting Boson Model predictions for the neutron-rich barium isotopes, assuming the quenching of the Z = 64 shell gap for N>88. The static hyperfine fields for implanted barium and cerium isotopes are found to be opposite in sign. These results constitute the first use of secondary-fragment gamma-ray emission in the determination of g-factors of excited states in fission fragments. (C) 1999 Elsevier Science B.V. All rights reserved.

Cross sections for proton knockout observed in ($e$,${e}^{\ensuremath{'}}p$) reactions are apparently quenched by a factor of $\ensuremath{\sim}0.5$, an effect attributed to short-range correlations between nucleons. Here we demonstrate that such quenching is not restricted to proton knockout, but a more general phenomenon associated with any nucleon transfer. Measurements of absolute cross sections on a number of targets between $^{16}\mathrm{O}$ and $^{208}\mathrm{Pb}$ were analyzed in a consistent way, with the cross sections reduced to spectroscopic factors through the distorted-wave Born approximation with global optical potentials. Across the 124 cases analyzed here, induced by various proton- and neutron-transfer reactions and with angular momentum transfer $\ensuremath{\ell}=0--7$, the results are consistent with a quenching factor of 0.55. This is an apparently uniform quenching of single-particle motion in the nuclear medium. The effect is seen not only in ($d$,$p$) reactions but also in reactions with $A=3$ and 4 projectiles, when realistic wave functions are used for the projectiles.

Proton pair correlations relevant for the neutrinoless double-$\ensuremath{\beta}$ decay of ${}^{76}$Ge have been probed via the ${}^{74,76}$Ge(${}^{3}$He,$n$) reactions at 16 MeV. No evidence for pairing vibrations in either nucleus is observed at sensitivity limits of $\ensuremath{\sim}$6$%$ and $\ensuremath{\sim}$19$%$ of the ground-state strength in ${}^{76}$Se and ${}^{78}$Se, respectively. These results are relevant for the understanding of matrix elements for neutrinoless double-$\ensuremath{\beta}$ decay. The lack of pairing vibrations is consistent with a simple BCS structure for the ground states of ${}^{76}$Ge and ${}^{76}$Se, assumed in quasiparticle random phase approximation (QRPA) models of the process.

Measurements of neutron-adding, neutron-removing, and proton-adding reactions were carried out for the four stable even Ni isotopes. Particular attention was paid to obtaining precise values of the cross sections at the peaks of the angular distributions. Tests with sum rules for the neutron data indicate that the results are self-consistent at the level of a few tenths of a nucleon. Data on proton-adding reactions were also obtained and analyzed with a slightly different method—while these data are also consistent, the ambiguities are larger. The occupancies of the neutron orbits derived from the data, the proton vacancies, and the energy centroids of the neutron, neutron-hole, and proton single-particle excitations are obtained. The data also provide some estimate about the closure of the 0 f 7 / 2 shell. The results are compared to shell-model calculations and may serve as a reference point for future exploration. ispartof: Physical Review C, Nuclear Physics vol:87 issue:3 pages:1-15 status: published

The single-neutron properties of N = 51 nuclei have been studied with the ( d , p )and( α , 3 He) reactions, at beam energies of 15 and 50 MeV respectively, on 88 Sr, 90 Zr, and 92 Mo targets. The light reaction products were momentum analyzed using a conventional magnetic spectrometer. Additionally, the 2 H( 86 Kr ,p ) reaction was measured at a beam energy of 10 MeV / u, where outgoing light ions were analyzed using a helical-orbit spectrometer. Absolute cross sections and angular distributions corresponding to the population of different final states in the heavy product were obtained for each reaction. Spectroscopic factors were extracted and centroids of the single-particle strength were deduced. The observations appear consistent with calculations based on an evolution of single-particle structure driven by the nucleon-nucleon forces acting between valence protons and neutrons. ispartof: Physical Review C, Nuclear Physics vol:87 issue:1 status: published

rays depopulating high-spin states in have been detected using the EUROGAM phase-1 array. A crossing which is possibly observed at a rotational frequency of MeV in a quasi-neutron band is interpreted as being due to the alignment of a pair of neutrons.

The pairing properties of the neutrinoless double-$\ensuremath{\beta}$ decay $(0\ensuremath{\nu}2\ensuremath{\beta})$ candidate ${}^{100}$Mo have been studied, along with its daughter ${}^{100}$Ru, to provide input for nuclear matrix element calculations relevant to the decay. The $(p,t)$ two-neutron transfer reaction was measured on nuclei of ${}^{102,100}$Ru and ${}^{100,98}$Mo. The experiment was designed to have particular sensitivity to ${0}^{+}$ states up to excitation energies of $\ensuremath{\sim}3$ MeV with high energy resolution. Measurements were made at two angles and $L=0$ transitions identified by the ratio of yields between the two angles. For the reactions leading to and from ${}^{100}$Ru, greater than $95%$ of the $L=0$ $(p,t)$ strength was in the ground state, but in ${}^{100}$Mo about $20%$ was in excited ${0}^{+}$ states. The measured $(p,t)$ data, together with existing $(t,p)$ data, suggest that ${}^{100}$Mo is a shape-transitional nucleus while ${}^{100}$Ru is closer to the spherical side of that transition. Theoretical calculations of the $0\ensuremath{\nu}2\ensuremath{\beta}$ nuclear matrix element may be complicated by this difference in shape.

Excited states have been identified in the very neutron-deficient $Z=58$ nucleus ${}^{123}$Ce. This is the most neutron-deficient odd-$A$ cerium isotope in which excited states have been identified. The states have been unambiguously assigned to ${}^{123}$Ce by detecting de-excitation $\ensuremath{\gamma}$ rays in coincidence with evaporated charged particles and neutrons. Three rotational bands, each consisting of at least eight $E2$ transitions, have been observed. The bands have tentatively been assigned to be based on neutrons in ${g}_{7/2}$ and ${h}_{11/2}$ orbitals. Two of the bands have been assigned to be signature partners, although no interband transitions have been observed. The aligned angular momenta of the bands have been studied in comparison with neighboring nuclei and with the results of Woods-Saxon cranking calculations. Observation of the deformation-dependent $\ensuremath{\pi}{({h}_{11/2})}^{2}$ quasiparticle alignment at 0.36 MeV/$\ensuremath{\hbar}$ in each of the bands suggests a quadrupole deformation of ${\ensuremath{\beta}}_{2}\ensuremath{\simeq}0.3$, in good agreement with theoretical predictions for the suggested possible configuration assignments.

Intermediate-energy Coulomb excitation measurements were performed on the neutron-rich isotopes ${}^{58,60,62}$Cr. The electric quadrupole excitation strengths, $B$($E$2; 0${}_{1}^{+}\ensuremath{\rightarrow}{2}_{1}^{+}$), of ${}^{60,62}$Cr are determined for the first time. The results quantify the trend of increasing quadrupole collectivity in the Cr isotopes approaching neutron number $N=40$. The results are confronted with large-scale shell-model calculations in the $fpgd$ shell using the state-of-the-art LNPS effective interaction. Different sets of effective charges are discussed that provide an improved and robust description of the $B(E2)$ values of the neutron-rich Fe and Cr isotopes in this region of rapid shell evolution. The ratio of the neutron and proton transition matrix elements, $|{M}_{n}/{M}_{p}|$, is proposed as an effective tool to discriminate between the various choices of effective charges.

The structure of ${}^{58}$Fe was investigated at Gammasphere using ${}^{48}$Ca(${}^{13,14}$C,$x$$n$) fusion-evaporation reactions at a beam energy of 130 MeV. The level scheme has been revised and extended to $J\ensuremath{\sim}17\ensuremath{\hbar}$ and an excitation energy of 16.6 MeV. Regular band structures consisting of low-energy $\ensuremath{\Delta}J=1\ensuremath{\hbar}$ transitions have been observed at moderate spin ($J\ensuremath{\sim}8\ensuremath{\hbar}$--15$\ensuremath{\hbar}$) and are candidates for magnetic rotational bands. Self-consistent tilted-axis-cranking calculations within a relativistic mean-field theory were applied to investigate these bands and were found to reproduce the experimental results well. In other parts of the level scheme, quasirotational bands composed of stretched-$E2$ transitions have been extended to high spin, and other new bands have been identified. Positive-parity experimental states were compared to predictions of the spherical shell model using the GXPF1A, KB3G, and FPD6 effective interactions in the $fp$ model space. The projected shell model, with a deformed quasiparticle basis including the neutron $\ensuremath{\nu}{g}_{9/2}$ orbital, was applied to interpret regular $\ensuremath{\Delta}J=2\ensuremath{\hbar}$ band structures that extend beyond the maximum spin available for $\ensuremath{\pi}$[(${f}_{7/2}$)${}^{\ensuremath{-}2}$] $\ensuremath{\bigotimes}$ $\ensuremath{\nu}$[(${p}_{3/2}{f}_{5/2}{p}_{1/2}$)${}^{4}$] configurations and exhibit features characteristic of rotational alignment. It is clear that the $\ensuremath{\nu}{g}_{9/2}$ intruder orbital plays a crucial role in describing the quasirotational structures in this nucleus, even starting as low as $J\ensuremath{\sim}5\ensuremath{\hbar}$.

Gamma-ray transitions have been observed in the proton-emitting $N=Z+2$ (${T}_{z}=1$) isotope ${}^{112}$Cs. The transitions have been unambiguously assigned to ${}^{112}$Cs by correlation with the characteristic proton decay, using the method of recoil-decay tagging with mass selection. The measured proton-decay energy and half-life are ${E}_{p}=810(5)$ keV and ${T}_{1/2}=470(50)$ $\ensuremath{\mu}$s, respectively, which are consistent with previous measurements. Five $\ensuremath{\gamma}$-ray transitions have been observed which appear to form a rotational sequence. The energy differences between excited states in the sequence are consistent with an assignment as the favored signature of the $\ensuremath{\nu}({h}_{11/2})\ensuremath{\bigotimes}\ensuremath{\pi}({h}_{11/2})$ structure. Tentative evidence for fine structure in the ${}^{112}$Cs proton decay is also observed.