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The 25Mg(p, γ )26Al reaction plays an important role in the study of cosmic 1.809 MeV γ -ray as a signature of ongoing nucleosynthesis in the Galaxy. At astrophysical temperature around 0.1 GK, the 25Mg(p, γ )26Al reaction rates are dominated by the 92 keV resonance capture process. We report a precise measurement of the 92 keV 25Mg(p, γ )26Al resonance in the day-one experiment at Jinping Underground Nuclear Astrophysics experiment (JUNA) facility in the China Jinping Underground Laboratory (CJPL). The resonance strength and ground state feeding factor are determined to be 3.8 ± 0.3 ×10−10 eV and 0.66 ± 0.04 , respectively. The results are in agreement with those reported in the previous direct underground measurement within uncertainty, but with significantly reduced uncertainties. Consequently, we recommend new 25Mg(p, γ )26Al reaction rates which are by a factor of 2.4 larger than those adopted in REACLIB database at the temperature around 0.1 GK. The new results indicate higher production rates of 26gAl and the cosmic 1.809 MeV γ -rays. The implication of the new rates for the understanding of other astrophysical situations is also discussed.

Charge-changing cross section ($\sigma_{\text{cc}}$) measurements via the transmission method have made important progress recently aiming to determine the charge radii of exotic nuclei. In this work, we report a new $\sigma_{\text{cc}}$ measurement of 304(9) MeV/nucleon $^{28}$Si on carbon at the second Radioactive Ion Beam Line in Lanzhou (RIBLL2) and describe the data analysis procedure in detail. This procedure is essential to evaluate the systematic uncertainty in the transmission method. The determined $\sigma_{\mathrm{cc}}$ of 1125(11) mb is found to be consistent with the existing data at similar energies. The present work will serve as a reference in the $\sigma_{\text{cc}}$ determinations at RIBLL2., Comment: 9 pages, 13 figures, to be published in Chinese Physics C

Observation of high energy and very high emission from Gamma Ray Bursts (GRBs) is crucial to study the gigantic explosion and the underline processes. With a large field-of-view and almost full duty cycle, the Water Cherenkov Detector Array (WCDA), a sub-array of the Large High Altitude Air Shower Observatory (LHAASO), is appropriate to monitor the very high energy emission from unpredictable transients such as GRBs. Nevertheless, the main issue for an extensive air shower array is the high energy threshold which limits the horizon of the detector. To address this issue a new trigger method is developed in this article to lower the energy threshold of WCDA for GRB observation. The proposed method significantly improves the detection efficiency of WCDA for gamma-rays around the GRB direction at 10-300 GeV. The sensitivity of the WCDA for GRB detection with the new trigger method is estimated. The achieved sensitivity of the quarter WCDA array above 10 GeV is comparable with that of Fermi-LAT. The data analysis process and corresponding fluence upper limit for GRB 190719C is presented as an example.

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 1015 electronvolts) indicates the existence of the so-called PeVatrons—cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays1. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. 2). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane3–6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators. Observations of γ-rays with energies up to 1.4 PeV find that 12 sources in the Galaxy are PeVatrons, one of which is the Crab Nebula.

Capture of electrons by nuclei is an important process in stellar environments where excited nuclear states are thermally populated. However, accurate treatment for excited configurations in electron capture (EC) rates has been an unsolved problem for medium-heavy and heavy nuclei. In this work, we take the $^{93}$Nb $\rightarrow$ $^{93}$Zr EC rates as the example to introduce the Projected-Shell-Model (PSM) in which excited configurations are explicitly included as multi-quasiparticle states. Applying the prevalent assumption that the parent nucleus always stays in its ground state in stellar conditions, we critically compare the obtained PSM results with the recently-measured Gamow-Teller transition data, and with the previous calculations by the conventional shell model and the quasiparticle random-phase approximation. We discuss important ingredients that are required in theoretical models used for stellar EC calculations, and demonstrate effects of the explicit inclusion of excited nuclear states in EC rate calculations, especially when both electron density and environment temperature are high.

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We report the discovery of a new unidentified extended $\gamma$-ray source in the Galactic plane named LHAASO J0341+5258 with a pre-trial significance of 8.2 standard deviations above 25 TeV. The best fit position is R.A.$=55.34^{\circ}\pm0.11^{\circ}$ and Dec$=52.97^{\circ}\pm0.07^{\circ}$. The angular size of LHAASO J0341+5258 is $0.29^\circ \pm 0.06^\circ_{stat} \pm0.02^\circ_{sys}$. The flux above 25 TeV is about $20\%$ of the flux of Crab Nebula. Although a power-law fit of the spectrum from 10 TeV to 200 TeV with the photon index $\alpha=2.98 \pm 0.19_{stat} \pm 0.02_{sys}$ is not excluded, the LHAASO data together with the flux upper limit at 10 GeV set by the Fermi LAT observation, indicate a noticeable steepening of an initially hard power-law spectrum %($\alpha \leq 1.75$) spectrum with a cutoff at $\approx 50$ TeV. We briefly discuss the origin of UHE gamma-rays. The lack of an energetic pulsar and a young SNR inside or in the vicinity of LHAASO J0341+5258 challenge, but do not exclude both the leptonic and hadronic scenarios of gamma-ray production., Comment: Accepted by APJL

The discrepancy between observations from γ-ray astronomy of the ^{60}Fe/^{26}Al γ-ray flux ratio and recent calculations is an unresolved puzzle in nuclear astrophysics. The stellar β-decay rate of ^{59}Fe is one of the major nuclear uncertainties impeding us from a precise prediction. The important Gamow-Teller strengths from the low-lying states in ^{59}Fe to the ^{59}Co ground state are measured for the first time using the exclusive measurement of the ^{59}Co(t,^{3}He+γ)^{59}Fe charge-exchange reaction. The new stellar decay rate of ^{59}Fe is a factor of 3.5±1.1 larger than the currently adopted rate at T=1.2 GK. Stellar evolution calculations show that the ^{60}Fe production yield of an 18 solar mass star is decreased significantly by 40% when using the new rate. Our result eliminates one of the major nuclear uncertainties in the predicted yield of ^{60}Fe and alleviates the existing discrepancy of the ^{60}Fe/^{26}Al ratio.

We report on an isomer yield ratio study of biologically important $^{94}\mathrm{Tc}$ following the fusion of the $^{9}\mathrm{Be}+^{89}\mathrm{Y}$ system, carried out using the offline $\ensuremath{\gamma}$-ray spectroscopy in continuation to the online activation method. The incident beam energies considered are above the Coulomb barrier for the present paper. The platypus model in conjunction with a potential model calculation was employed to analyze the data. An agreement in the order of magnitude between the experimental data and the theoretical predictions has been achieved by applying a phenomenological approach. The approach was further tested with isomer yield ratios of $^{94}\mathrm{Tc}$ formed through $^{3}\mathrm{He}+^{93}\mathrm{Nb}$ reactions. Possible factors that relate to the isomer yield ratios are also presented.

The main scientific goal of the LHAASO WFCTA experiment is to measure the cosmic ray energy spectra and composition from 10 TeV to 1 EeV. Cherenkov photons in the extensive air shower measured by the SiPM camera of Cherenkov telescopes can be used to reconstruct the cosmic ray energy. The absolute calibration of the camera is a crucial step to achieve the accurate measurement of the cosmic ray energy spectrum. A multi-wavelength cylindrical illuminator based on LEDs is developed and mounted inside the telescope to calibrate and monitor the camera, and the illuminator’s stability is better than 0.5% under the temperature variation from -26 to 26 ° C. A portable probe with a single photoelectron resolution of 21.6% is developed. After calibration by National Institute of Metrology, China (NIM), the probe is taken to the LHAASO site to measure the absolute photon density of the cylindrical illuminator inside the telescope. Based on the illuminator with known photon density, the photon conversion factor of the camera can be calibrated, and the overall calibration uncertainty is less than 2.6%.

An end-to-end calibration method, which is different from the traditional way, has been employed in WFCTA prototype experiment based on N 2 laser. As we known, the calculation of the expected and the observed light fluxes at the front of the aperture of the telescope are crucial in the such method. To calculate predicted light flux accurately, the propagation and scattering of photons in the atmosphere have been considered in detail. In order to get the detector effective areas, which will be used in the transformation of ADC signals to the observed light flux, a ray trace procedure, considering all details of detector response, has been performed for all incident direction of photons in field of view of the detector. By matching the observed and expected light flux at the entrance of the telescope, the overall calibration gains of two telescopes can be obtained. During the test run of the calibration, a overall calibration gain around G = 0 . 38 A D C c o u n t s ∕ p h o t o n and G = 0 . 36 A D C c o u n t s ∕ p h o t o n for WFCT01 and WFCT02 are given, respectively. Furthermore, in view of all uncertainty sources, systematic uncertainties for the calibration have also been estimated. They are around the level of ( − 7 . 3 % , + 7 . 8 % ) . The calibration results achieved by end-to-end method and the traditional way are in consistent at the level of 10%, which is within the range of uncertainties. Since the end-to-end and traditional calibration methods have their own advantages, the performance of the combination of these two calibration methods has also been discussed in the end.

Heavy-ion fusion reactions, such as 12 C+ 12 C, play crucial roles in stellar evolution and nucleosynthesis in massive stars . However, limited by the low cross section and large background, it is very challenging to study the reactions at stellar energies. We have developed a 1024-channel prototype TPC named MATE (Multi-purpose time projection chamber for nuclear AsTrophysical and Exotic beam experiments) to study these reactions at stellar energies. The design of our prototype TPC and its performance are described, and the preliminary results of a commissioning experiment for measuring the 12 C( 12 C, α 0 ) 20 Ne reaction at E cm = 3.0 MeV are presented. Perspectives of future experiments for the 12 C+ 12 C fusion cross section measurement are also provided.

Complete fusion (CF) cross section measurement for the weakly bound 9Be projectile interacting with the intermediate mass target 89Y has been extended to energies greater than the fusion barrier, by implementing off-line characteristic γ -ray detection techniques. The available experimental data for the 9Be + 89Y reaction system were compared with the theoretical predictions, using the PLATYPUS code that is based on a classical dynamical model. By introducing the breakup probability that deduced in the literature from the fitting of the experimental data, the model managed to reproduce the CF cross sections of 9Be beam with targets of different atomic mass. Through the study, it is revealed that the extended CF excitation function for the 9Be + 89Y system is consistent with the systematical behavior that the prompt-breakup probability at above-barrier energies is roughly independent of the target in the reactions induced by the same weakly bound projectiles.

31st International Conference on Photonic, Electronic and Atomic Collisions, ICPEAC XXXI, Caen, France, 23 Jul 2019 - 30 Jul 2019; Journal of physics / Conference series Conference series [...] 1412, 142015 (2020). doi:10.1088/1742-6596/1412/14/142015, Published by IOP Publ., Bristol

We report first precision mass measurements of the $1/2^-$ isomeric and $9/2^+$ ground states of $^{101}$In. The determined isomeric excitation energy continues a smooth trend of odd-$A$ indium isotopes up to the immediate vicinity of $N=50$ magic number. This trend can be confirmed by dedicated shell model calculations only if the neutron configuration mixing is considered. We find that the single particle energies are different for different states of the same isotope. The presented configuration-dependent shell evolution, type II shell evolution, in odd-$A$ nuclei is discussed for the first time. Our results will facilitate future studies of single-particle neutron states.

The cross sections of complete fusion and incomplete fusion for the $^{9}\mathrm{Be}+^{197}\mathrm{Au}$ system, at energies not too much above the Coulomb barrier, were measured for the first time. The online activation followed by an offline $\ensuremath{\gamma}$-ray spectroscopy method was used for the derivation of the cross sections. A slightly higher value of the incomplete fusion to total fusion ratio has been observed, compared to other systems reported in the literature with a $^{9}\mathrm{Be}$ beam. The experimental data were compared with coupled channel calculations without taking into account the coupling of the breakup channel, and experimental data of other reaction systems with weakly bound projectiles. A complete fusion suppression of about 40% was found for the $^{9}\mathrm{Be}+^{197}\mathrm{Au}$ system, at energies above the barrier, whereas the total fusion cross sections are in agreement with the calculations.

Author(s): Titus, R; Ney, EM; Zegers, RGT; Bazin, D; Belarge, J; Bender, PC; Brown, BA; Campbell, CM; Elman, B; Engel, J; Gade, A; Gao, B; Kwan, E; Lipschutz, S; Longfellow, B; Lunderberg, E; Mijatovic, T; Noji, S; Pereira, J; Schmitt, J; Sullivan, C; Weisshaar, D; Zamora, JC | Abstract: Background: In the late stages of stellar core collapse just prior to core bounce, electron captures on medium-heavy nuclei drive deleptonization. Therefore, simulations require the use of accurate reaction rates. Nuclei with neutron number near N=50 above atomic number Z=28 play an important role. Rates presently used in astrophysical simulations rely primarily on a relatively simple single-state approximation. In order to improve the accuracy of the astrophysical simulations, experimental data are needed to test the electron-capture rates and to guide the development of better theoretical models and astrophysical simulations. Purpose: The purpose of the present work was to measure the Gamow-Teller transition strength from Kr86 to Br86, to derive the stellar electron-capture rates based on the extracted strengths, and to compare the derived rates with rates based on shell-model and quasiparticle random-phase approximation (QRPA) Gamow-Teller strengths calculations, as well as the single-state approximation. An additional purpose was to test the impact of using improved electron-capture rates on the late evolution of core-collapse supernovae. Method: The Gamow-Teller strengths from Kr86 were extracted from the Kr86(t,He3+γ) charge-exchange reaction at 115MeV/u. The electron-capture rates were calculated as a function of stellar density and temperature. Besides the case of Kr86, the electron-capture rates based on the QRPA calculations were calculated for 78 additional isotopes near N=50 above Z=28. The impact of using these rates instead of those based on the single-state approximation is studied in a spherically symmetrical simulation of core collapse just prior to bounce. Results: The derived electron-capture rates on Kr86 from the experimental Gamow-Teller strength distribution are much smaller than the rates estimated based on the single-state approximation. Rates based on Gamow-Teller strengths estimated in shell-model and QRPA calculations are more accurate. The core-collapse supernova simulation with electron-capture rates based on the QRPA calculations indicate a significant reduction in the deleptonization during the collapse phase. Conclusions: It is important to utilize microscopic theoretical models that are tested by experimental data to constrain and estimate Gamow-Teller strengths and derived electron-capture rates for nuclei near N=50 that are inputs for astrophysical simulations of core-collapse supernovae and their multimessenger signals, such as the emission of neutrinos and gravitational waves.

The isomer yield ratios of 184R in the incomplete fusion of the 9Be + 181Ta system were measured at energies around the Coulomb barrier, using online activation followed by offline γ-ray spectroscopy method. The PLATYPUS code that is based on a classical dynamical model is employed to analyze the measurements. By applying a phenomenological approach, model calculation managed to fairly reproduce the order of magnitude of the yield ratios at above barrier energies. Through the study, it is shown that the PLATYPUS code in conjunction with a phenomenological analysis can provide a reasonable explanation of isomer yield ratios resulted from incomplete fusion of weakly bound projectiles.

A neutron detector array consisting of a cylindrical plastic scintillator and 24 Helium-3 proportional counters is developed for the detection of neutrons with an extremely low rate. This detector array is designed for the JUNA (Jinping Underground Nuclear Astrophysics laboratory) project to measure the 13C ( α , n) 16O reaction cross-section at stellar energies in CJPL (China Jinping Underground Laboratory). In this paper, we introduce the design of this detector array. The responses of the plastic scintillator to gamma rays and neutrons are tested at the ground level by shielding the detector array with a lead room. The neutron detection efficiency is obtained with a 252Cf source and a PuC source. The measured result is reproduced by Monte Carlo simulation. The coincidence measurement between plastic scintillator and Helium-3 counters is also performed and the coincidence times are obtained. These tests lay the foundation for the future measurement of the 13C ( α , n) 16O reaction cross-section in CJPL.

A heavy-ion detector was developed for decay studies in the Experimental Storage Ring (ESR) at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. This detector serves as a prototype for the in-pocket particle detectors for future experiments with the Collector Ring (CR) at FAIR (Facility for Antiproton and Ion Research). The detector includes a stack of six silicon pad sensors, a double-sided silicon strip detector (DSSD), and a CsI(Tl) scintillation detector. It was used successfully in a recent experiment for the detection of the β+-decay of highly charged 142Pm60+ ions. Based on the Δ E / E technique for particle identification and an energy resolution of 0.9% for Δ E and 0.5% for E (Full Width at Half Maximum (FWHM)), the detector is well-suited to distinguish neighbouring isobars in the region of interest.

Isochronous mass spectrometry was applied to measure isomeric yield ratios of fragmentation reaction products. This approach is complementary to conventional gamma-ray spectroscopy in particular for measuring yield ratios for long-lived isomeric states. Isomeric yield ratios for the high-spin I = 19/2 states in the mirror nuclei 53Fe and 53Co are measured to study angular momentum population following the projectile fragmentation of 78Kr at energies of 480A MeV on a beryllium target. The 19/2 state isomeric ratios of 53Fe produced from different projectiles in the literature have also been extracted as a function of mass number difference between projectile and fragment (mass loss). The results are compared to ABRABLA07 model calculations. The isomeric ratios of 53Fe produced using different projectiles suggest that the theory underestimates not only the previously reported dependence on the spin but also the dependence on the mass loss., Comment: 6 pages, 5 figures

In isochronous mass spectrometry (IMS) established in heavy-ion storage rings the revolution times of the stored secondary ions should be independent of their velocity spread. However, this isochronous condition is fulfilled only in first order and in a small range of revolution times. To correct for the non-isochronicity an additional measure of the velocity or magnetic rigidity of each stored ion is required. For this purpose two new time-of-flight (TOF) detectors were installed in a straight section of the experimental Cooler Storage Ring CSRe in Lanzhou. The performance of the new time-of-flight (TOF) detectors, which is crucial for the achievable efficiencies and mass resolving power, was significantly improved. The time resolution of the TOF detector in offline tests was σ = 18.5 ± 2 ps . The detector setup was put into operation with a stable beam of 78Kr.

International audience; In this work, we present a pilot experiment in the experimental storage ring (ESR) at GSI devoted to impact parameter sensitive studies of inner shell atomic processes for low-energy (heavy-) ion-atom collisions. The experiment was performed with bare and He-like xenon ions (Xe 54+ , Xe 52+ ) colliding with neutral xenon gas atoms, resulting in a symmetric collision system. This choice of the projectile charge states was made in order to compare the effect of a filled K-shell with the empty one. The projectile and target X-rays have been measured at different observation angles for all impact parameters as well as for the impact parameter range of ∼35–70 fm.

利用非完全熔合反应 192 Os( 7 Li, ( p, d, t ) xn )布居了稳定核 195 Pt的高自旋态. 根据 γ - γ 符合关系、 γ 射线的相对强度和各向异性度的测量结果, 建立了 195 Pt核的能级纲图, 其中包括11条新的 γ 跃迁和9个新能级. 通过与邻近核的能级系统性比较, 指出了 195 Pt核基于 vi 13/2 -1 和 vi 13/2 -2 vj -1 ( j = p 3/2 , f 5/2 )组态的转动带能级结构. 同时, 利用Total-Routhian-Surface (TRS)理论计算结果讨论了 195 Pt核的转动带性质.

利用能量为44 MeV的 13 C束流, 通过重离子熔合蒸发反应 82 Se( 13 C, 4n) 91 Zr布居了稳定核 91 Zr的高自旋态. 基于γ-γ符合关系扩展了 91 Zr 21/2 + 同核异能态上的能级纲图, 根据实验提取的γ跃迁的角分布系数对部分能级的自旋进行了指认. 前人对21/2 + 同核异能态下正负宇称能级已指认为质子在π(p 1/2 , g 9/2 )轨道的激发耦合价中子νd 5/2 ; 在π(f 5/2 , p 3/2 , p 1/2 , g 9/2 )和ν(d 5/2 , s 1/2 , d 3/2 , g 7/2 , h 11/2 )空间内, 经过系统性的分析和比较 91 Zr邻近核高自旋态能级结构, 指出同核异能态上正宇称态激发机制依次为质子跨越38子壳π(f 5/2 , p 3/2 )→πp 1/2 激发和中子跨越50闭壳νg 9/2 →νd 5/2 激发, 同核异能态上负宇称态可能涉及质子跨越38子壳π(f 5/2 , p 3/2 )→πg 9/2 激发与价中子νd 5/2 →νh 11/2 激发的竞争.

Highly charged radioactive ions can be stored for extended periods of time in storage rings which allows for precision measurements of their decay modes. The straightforward motivation for performing such studies is that fully ionised nuclei or few-electron ions can be viewed as clean quantum-mechanical systems, in which the interactions of the many electrons can be either excluded or treated precisely. Thus, the influence of the electron shell on the decay probability can be investigated. Another important motivation is stellar nucleosynthesis, which proceeds at high temperatures and the involved atoms are therefore highly ionised. Presented here is a compact review of the relevant experiments conducted at heavy-ion storage rings. Furthermore, we outline the perspectives for future experiments at new-generation storage-ring facilities.

We report the results of the measurements of complete and incomplete fusion of the ${}^{9}\text{Be}+{}^{169}\text{Tm}$ and $^{187}\mathrm{Re}$ systems at energies close to the Coulomb barrier. The activation technique with the detection of offline gamma rays was used to derive the cross sections. By comparing the experimental cross sections with coupled-channel calculations that do not include the breakup channel, we found suppression of the complete fusion of the order of 30% for both systems, at energies slightly above the barrier. This suppression corresponds roughly to the measured incomplete fusion. We also investigate a systematic behavior of the suppression of complete fusion cross sections for $^{9}\mathrm{Be}$ on different targets and we found that it does not depend on the target.

One neutron transfer cross sections from the interaction of 9 Be with 89 Y have been measured at energies greater than the fusion barrier. The present measured 1n-transfer cross sections saturate at well above energies in comparison with the available experimental data at lower energies. Results of Coupled Reaction Channels Calculations (CRC) show very good agreement with the present measured cross sections.

Atomic charge states can significantly influence nuclear decay rates. Presented is a compact overview of experiments conducted at the Experimental Storage Ring ESR of GSI addressing β-decay of stored and cooled highly charged ions. Investigations of the two-body beta decay, namely the bound-state β-decay and its time-mirrored counterpart, orbital electron-capture, are discussed in more details and a special emphasis is given to the future experiment on the bound-state β-decay of fully-ionized 205Tl81+ nuclei.

Complete and incomplete fusion cross sections for the $^{9}\mathrm{Be}$ $+\phantom{\rule{0.16em}{0ex}}^{181}\mathrm{Ta}$ system were measured at near barrier energies, using the offline gamma ray spectroscopy method. The results were compared with coupled channel calculations that do not take into account the coupling of the breakup channel, using a double folding potential as bare potential. A complete fusion suppression of the order of 35% was found, at energies above the barrier, whereas the total fusion cross sections are in agreement with the calculations. The ratio between incomplete fusion and total fusion at energies above the Coulomb barrier was found to be $32\ifmmode\pm\else\textpm\fi{}1%$. At sub-barrier energies one observes some enhancement of total fusion cross section.

High-spin level structures of the near-spherical nuclei ${}^{91,92}$Zr have been reinvestigated via the ${}^{82}$Se(${}^{13}$C, $xn$) $(x=4,3)$ reactions at a beam energy of 44 MeV. By the use of in-beam spectroscopic methods, 13 new transitions belonging to ${}^{91}$Zr and 19 to ${}^{92}$Zr have been observed and the level schemes of ${}^{91,92}$Zr have been extended up to ${E}_{x}\ensuremath{\approx}$ 11 MeV excitation energy. The newly constructed level schemes are characterized by the ${}^{88}$Sr core breaking, and the proton ${p}_{3/2}\text{\ensuremath{-}}{p}_{1/2}$ energy gap in ${}^{92}$Zr is obviously reduced compared with ${}^{91}$Zr when one more neutron goes into the $({d}_{5/2}/{g}_{7/2})$ orbital.

The high-spin level structure of the doubly odd nucleus ${}^{104}$Ag has been investigated via the ${}^{97}$Mo(${}^{11}$B, 4n)${}^{104}$Ag reaction at a beam energy of 50 MeV. The newly established level scheme includes lower-lying two-quasiparticle states and several higher-lying bands. Two positive-parity bands associated with the $\ensuremath{\pi}{g}_{9/2}^{\ensuremath{-}1}\ensuremath{\bigotimes}\ensuremath{\nu}{d}_{5/2}$ and $\ensuremath{\pi}{g}_{9/2}^{\ensuremath{-}1}\ensuremath{\bigotimes}\ensuremath{\nu}{g}_{7/2}$ configurations are extended significantly. Based on the comparison with the analogous structures in neighboring nuclei and the features of nuclear chirality, the negative parity bands are suggested as candidate chiral doublet bands with the $\ensuremath{\pi}{g}_{9/2}^{\ensuremath{-}1}\ensuremath{\bigotimes}\ensuremath{\nu}{h}_{11/2}$ configuration.

High-spin states in ${}^{184}$Au have been investigated by means of in-beam $\ensuremath{\gamma}$-ray spectroscopy techniques using the multidetector array of GASP. Excited states of ${}^{184}$Au were populated via the ${}^{159}$Tb(${}^{29}$Si, 4$n$$\ensuremath{\gamma}$) reaction at a beam energy of 140 MeV. The previously known bands based on the $\ensuremath{\pi}{h}_{9/2}\ensuremath{\bigotimes}\ensuremath{\nu}7/{2}^{\ensuremath{-}}[514]$, $\ensuremath{\pi}{h}_{9/2}\ensuremath{\bigotimes}\ensuremath{\nu}1/{2}^{\ensuremath{-}}[521]$, $\ensuremath{\pi}{h}_{9/2}\ensuremath{\bigotimes}\ensuremath{\nu}{i}_{13/2}$, and $\ensuremath{\pi}{i}_{13/2}\ensuremath{\bigotimes}\ensuremath{\nu}{i}_{13/2}$ configurations have been extended. Three new rotational bands have been identified and assigned as the prolate $\ensuremath{\pi}1/{2}^{+}[660]\ensuremath{\bigotimes}\ensuremath{\nu}7/{2}^{\ensuremath{-}}[514]$ and $\ensuremath{\pi}11/{2}^{\ensuremath{-}}[505]\ensuremath{\bigotimes}\ensuremath{\nu}7/{2}^{\ensuremath{-}}[514]$ and oblate $\ensuremath{\pi}{h}_{11/2}^{\ensuremath{-}1}\ensuremath{\bigotimes}\ensuremath{\nu}{i}_{13/2}^{\ensuremath{-}1}$ configurations, respectively. Experimental aligned angular momenta, band-crossing frequencies, and electromagnetic properties have been analyzed in the framework of the cranked shell model. Low-spin signature inversion has been observed in the prolate $\ensuremath{\pi}{h}_{9/2}\ensuremath{\bigotimes}\ensuremath{\nu}{i}_{13/2}$ and $\ensuremath{\pi}{i}_{13/2}\ensuremath{\bigotimes}\ensuremath{\nu}{i}_{13/2}$ and oblate $\ensuremath{\pi}{h}_{11/2}^{\ensuremath{-}1}\ensuremath{\bigotimes}\ensuremath{\nu}{i}_{13/2}^{\ensuremath{-}1}$ bands of ${}^{184}$Au.

The European physical journal / Web of Conferences 93, 05003 (2015). doi:10.1051/epjconf/20159305003, Published by EDP Sciences, Les Ulis

The complete fusion reaction 40 Ca+ 175 Lu was studied at a beam energy of 5.1 MeV u �1 . Evaporation residues recoiled from the target were separated from the primary beam by the gas-filled recoil separator SHANS and then implanted into the focal plane detection system. Based on the energy-positiontime correlation measurement, neutron-deficient nuclei − 208 213 Ac, 212 Pa and 211 Th produced in this reaction were identified. Previously reported decay properties of the ground state in 212 Pa were confirmed and improved values of − + 5.1 1.7 ms and 8.250(20) MeV for the half-life and α-particle energy of 212 Pa were obtained. No correlated decay chain arising from 211 Pa was observed and an upper limit for the cross section of 211 Pa was estimated.