Revisiting band structures in^(118)Xe nucleus via in-beamγ-ray spectroscopy

The neutron deficient Xe nuclei with A≈120 are predicted to have strong octupole correlation at low spins.In the present study,an attempt was made to improve upon the level scheme and also to examine the signatures of octupole correlation in^(118)xe via high spin γ-ray spectroscopy.High spin states in^(118)Xe have been populated via the^(93)Nb(^(28)Si,p2n)^(118)Xe fusion-evaporation reaction at a beam energy of 115 MeV provided by the 15 UD pelletron accelerator facility at IUAC,New Delhi.In the experiment,seven newγ-transitions have been found and placed appropriately in the level scheme.A theoretical study using the triaxial projected shell model(TPSM)approach suggests that the first bandcrossing is due to the alignment of two neutrons,and a parallel band tracking the yrast configuration is the γ-band built on the two-quasiparticle state.Enhanced E1 transition rates measured between opposite parity bands involving vh_(11/2)and vd_(5/2)orbitals having△j=△l=3 indicate the presence of octupole correlation in this nucleus.

γ-ray Spectroscopy of Hypernuclei:Recent KEK Results and Future Plans at J-PARC

In this proceeding,we will first outline the experimental setup and main results of the most recent hypernuclear γ-ray spectroscopy experiment (KEK-E566) performed at KEK-PS K6 beam line. The main feature and characteristics of this type of research will be emphasised. After that,the approved experimental proposal (E13) at J-PARC facility will be introduced briefly.

Mass Yield Distribution in Intermediate Energy Heavy Ion Reactions

The production cross sections of the target residues were measured for the 40 MeV/u40Ar+Cu reaction by γ-ray spectroscopic technique and the mass yield distribution was deduced.The ex-perimental data were compared with the theoretical results from both the GEMINI code based on the statis-tical binary decay model and the McFRAG code based on the fusion-fragmentation model.

Cross-sections of the ^(238)U(n,γ) ^(239)U reaction in the 3.0-7.0 MeV energy region measured by relative activation method

The reaction cross-sections of^(238)U(n,γ)^(239)U have been experimentally determined at neutron energies of6.117±0.119 MeV,4.626±0.086 MeV,and 3.622±0.348 MeV employing the relative activation approach along with the off-line γ-ray spectroscopy method.The D(d,n)3He reaction was utilized to obtain monoenergetic neutrons of the required energy,and the^(197)Au(n,γ)^(198)Au reaction cross-sections were adopted as the referential standard to ascertain the neutron capture cross-sections of^(238)U.Furthermore,the effects of low-energy scattered neutrons,neutron fluence fluctuations,counting of geometric corrections when measuring γ-rays,and neutron and γ-ray self-absorption caused by the sample thickness have been considered and revised in the present work.For a comparison with experimental results,the cross-sections of the^(238)U(n,γ)^(239)U reaction were calculated theoretically with the original parametric TALYS-1.9 program.The experimental measurements were in contrast to previous experimental re sults and the evaluation data available for ROSFOND-2010,CENDL-3.2 and ENDF/B-VIII.0.

Isomeric pair 95m,g Nb in the photonuclear reactions on natMo at the bremsstrahlung end-point energy of 38–93 MeV

The ^(nat)Mo(γ,xnp)^(95m,g)Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40.The experiment was performed using the activation and off-line γ-ray spectrometric technique.The experimental isomeric yield ratio(IR) was determined for the reaction products ^(95m,g)Nb at the bremsstrahlung end-point energy E_(γmax) range of 38-93 MeV.The obtained values of IR are in satisfactory agreement with the results of other studies and extend the range of previously known data.The theoretical values of the yields Y_(m,g)(E_(γmax)) and the IR for the isomeric pair ^(95m,g)Nb from the ^(nat)Mo(γ,xnp) reaction were calculated using the partial cross-sections σ(E) from the TALYS1.95 code for six different level density models.For the investigated range of E_(γmax),the theoretical dependence of IR on energy was confirmed-the IR smoothly increases with increasing energy.The comparison showed a noticeable difference(more than 3.85 times) in the experimental IR relative to all theoretical estimates.

Cross-sections of photonuclear reactions ^(65)Cu(γ, n)^(64)Cu and ^(63)Cu(γ, xn)^(63−x)Cu in the energy range E_(γmax) = 35–94 MeV

The flux-averaged cross-sections<σ(E_(γmax))>for the reactions^(65)Cu(γ,n)^(64)Cu,^(63)Cu(γ,n)^(62)Cu,^(63)Cu(γ,2n)^(61)Cu,and^(63)Cu(γ,3n)^(60)Cu have been measured within the bremsstrahlung end-point energy E_(γmax)range of 35–94 MeV.The experiments were performed with the electron beam from the NSC KIPT linear accelerator LUE-40 with the use of the activation and off-lineγ-ray spectrometric techniques.Theoretical calculation of the flux-average cross-sections<σ(E_(γmax))>_(th)was conducted using the cross-sectionσ(E)values from the TALYS1.95 code,run with default options.It is shown that the experimental average cross-sections for the reactions^(65)Cu(γ,n)^(64)Cu,^(63)Cu(γ,n)^(62)Cu,and^(63)Cu(γ,2n)^(61)Cu are systematically higher than the theoretical estimates based on the TALYS1.95 code.The obtained<σ(E_(γmax))values supplement the data of different laboratories for the(γ,n)and(γ,2n)reactions of^(63)Cu and^(65)Cu.For the reaction^(63)Cu(γ,3n)^(60)Cu,the values of<σ(E_(γmax))>were measured for the first time.

Cross-sections for the 27Al(γ,x)22Na multichannel reaction with the 28.3 MeV difference of reaction thresholds

The bremsstrahlung flux-averaged cross-sections(σ(Eγmax))and the cross-sections per equivalent photon(σ(Eγmax)Q)were first measured for the photonuclear multichannel reaction ^(27)Al(γ,x)22 Na at end-point bremsstrahlung gamma energies ranging from 35 MeV to 95 MeV.The experiments were performed with the beam from the NSC KIPT electron linear accelerator LUE-40 using theγ-activation technique.The bremsstrahlung quantum flux was calculated with the GEANT4.9.2 program and was also monitored via the ^(100)Mo(γ,n)^(99)Mo reaction.The flux-averaged cross-sections were calculated using the partial cross-sectionσ(E)values computed with the TALYS1.95 code for different level density models.Consideration is given to special features of calculating the cross-sections<σ(Eγmax)>and<σ(Eγmax)Q>for the case of the final nucleus ^(22)Na via several partial channels x:nα+dt+npt+2 n^(3) He+n2d+2 npd+2 p3 n.

Isomeric ratio of the ^(181)Ta(γ,3n)^(178m,g)Ta reaction products at energy Eγmax up to 95 MeV

The photoneutron reaction^(18)Ta(y,3m)(178m,g)Ta was investigated with the beam from the NSC KIPT electron linear accelerator LUE-40.The measurements were performed using the residual y-activity method.The bremsstrahlung flux-averaged cross sections((E_(γmax))>.(r(E_(γmax))>m.<r(E_(γmax))g and the isomerie ratio of the re-action products d(E_(γmax))were measured.The theoretical values of the averaged cross-sections and isomeric ratio were calculated using the partial cross-sections from the TALYS1.95 code for different level density models LD 1-6..The obtained experimental d(E_(γmax))agree with the data in the lterature,but differ from the theoretical values in ab-solute magnitude and the behavior of the energy dependence.A comparison of the determined averaged cross-sec-tions with the calculated cross sections showed the best agreement for the case of the LD 5 model.

Shape co-existence and structural evolution of the vi_(13/2) band in ^(157)Yb

The high-spin states of 157Yb have been studied via the reaction of 144Sm(16O, 3n) at 16O energy of 90 MeV using techniques of in-beam γ-ray spectroscopy. Measurement of γ-γ-t coincidences was performed with 11 BGO(AC)HPGe detectors. Based on the γ-γ coincidence relationships and the measured results of γ-ray anisotropies and DCO ratios, the level scheme for 157Yb was established. The shape co-existence and structural evolution of the Vi13/2 band with increasing angular momentum in 157Yb have been discussed. The systematics of the Vi13/2 bands in the N = 87 odd-A isotones have been compared.

High-spin states in ^(190)Pt

The level structure of ^19Opt has been studied experimentally using the ^176yb （^18O, 4n） reaction at beam energies of 88 and 95 MeV. γ-γ-t coincidence measurements were carried out. Based on the analysis of T-T coincidence relationships, the level scheme of ^190Pt is extended to high-spin states. A new structure built on the 3413.6 keV 14＋ state has been observed, and the ＂vi13/2^-2 vh9/2^-1 vj （j = P3/2 or f5/2） configuration is tentatively assigned to it.

Cross-sections for(n,2n),(n,α),(n,p),(n,d),and(n,t)reactions on molybdenum isotopes in the neutron energy range of 13 to 15 MeV

Given the insufficient cross-sectional data regarding the 14-MeV-neutron experiment of molybdenum,the vital fusion reactor structural material,and the significant heterogeneities among the reported values,this study examined the(n,2n),(n,α),(n,p),(n,d),and(n,t)reaction cross sections in molybdenum isotopes based on the neutrons produced via a T(d,n)4He reaction carried out in the Pd-300 Neutron Generator at the China Academy of Engineering Physics(CAEP).A high-resolution gamma-ray spectrometer,which was equipped with a coaxial high-purity germanium detector,was used to measure the product nuclear gamma activities.In addition,27Al(n,α)24Na and 93Nb(n,2n)92mNb reactions were utilized as the neutron fluence standards.The experimental 92Mo(n,2n)91Mo,94Mo(n,2n)93mMo,100Mo(n,2n)99Mo,98Mo(n,α)95Zr,100Mo(n,α)97Zr,92Mo(n,p)92mNb,96Mo(n,p)96Nb,97Mo(n,p)97Nb,98Mo(n,p)98mNb,92Mo(n,d)91mNb,and 92Mo(n,t)90Nb reaction cross sections were acquired within the 13-15 MeV neutron energy range.Thereafter,we compared and analyzed these obtained cross sections based on the existing IAEA-EXFOR database-derived experimental data,together with evaluation results corresponding to ENDF/B-Ⅷ.0,JEFF-3.3,BROND-3.1,and CENDL-3.1 and the theoretical outcomes acquired through TALYS-1.95 and EMPIRE-3.2.3(nuclear-reaction modeling tools).

Measurements of ^(nat) Cd(γ,x)reaction cross sections and isomer ratio of ^(1,5m.g)Cd with the bremsstrahlung end-point energies of 50 and 60 MeV

The flux-weighted average cross sections ^(nat) Cd(γ,xn)^(115g,m,111m,109,107,105,104)Cd and ^(nat) Cd(γ,x)^113g,112,111g,110m)Ag reactions were measured at the bremsstrahlung end-point energies of 50 and 60 MeV.The activa tion and off-line y-ray spectrometric technique was carried out using the 100 MeV electron linear accelerator at the Pohang Accelerator Laboratory,Korea.The ^(nat)lCd(γ,xn) reaction cross sections as a function of photon energy were theoretically calculated using the TALYS-1.95 and the EMPIRE-3.2 Malta codes.Then,the flux-weighted average cross sections were obtained from the theoretical values of mono-energetic photons.These values were compared with the flux-weighted values from the present study and were found to be in general agreement.The measured experimental reaction cross-sections and integral yields were described for cadmium and silver isotopes in the ^(nat)Cd(γ,xn)^(115g,m,111m,109,107,105,104) and ^(nat)Cd(γ,x)^(113g,112.111g,110m)Ag reactions.The isomeric yield ratio(IR) of ^(115g.m)Cd in the ^(nat)Cd(γ,xn) reaction was determined for the two bremsstrahlung end-point energies.The measured isomeric yield ratios of ^(115g,m)Cd in the ^(nat)Cd(γ,xn) reaction were also compared with the theoretical values of the nuclear model codes and previously published literature data of the ^(116)Cd(γ,x) and ^116(γ,2n) reactions.It was found that the IR value increases with increasing projectile energy,which demonstrates the characteristic of excitation energy.However,the higher IR value of ^(115g.m)Cd in the ^(116)Cd(n,2n)reaction compared to that in the ^(116)Cd(γ,x)reaction indicates the role of compound nuclear spin alongside excitation energy.

Measurement of ^(59)Co(ai,x)reaction cross sections with the fast neutrons based on the ^(9)Be(p,n)reaction

The cross sections of the ^(59)Co(n,x)reaction in the average energy range of 15.2-37.2 MeV were meas-ured using activation and an off-line γ-ray spectrometric technique.The neutrons were generated from the ^(9)Be(p,n)reaction with proton beam energies of 25-45 MeV at the MC-50 Cyclotron facility of the Korean Institute of Radi-ological and Medical Sciences(KIRAMS).Theoretical cal lculations of neutron-induced reactions on ^(59)Co were per-formed using the nuclear model code TALYS-1.9.The results for the ^(59)Co(n,x)reactions were compared with the theoretical values obtained using TALYS-1.9 and the literature data provided in EXFOR and the TENDL 2019 nuc-lear data library.The theoretical values obtained using TALYS-1.9 with adjusted parameters are comparable to the experimental data.The measured reaction cross sections of a few radionuclides are new,and the others are compar-able to the literature data,and thus,they can strengthen the database.The present study on cross sections leads to useful insight into the mechanisms of ^(59)Co(n,x)reactions.