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International audience; The excitation function of the $^{238}$U($^{9}$Be, 5$n$) reaction was obtained for the first time. By using a stack of uranium targets, 20 experimental data were obtained by the on-line irradiation without changing beam energy. Taking the advantage of the long lifetime and α decay mode of the residue nucleus $^{242}$Cm, the off-line measurement of the α radioactive was performed to obtain its yields. The maximum cross section is about 1 mb. The curve's shape and the maximum's position agree with the present model. The value of the cross section will help us to develop the ralated models, and push the nuclear studies in the transuranium region.

A method is presented for the measurement of differential cross-sections of heavy ion elastic scattering induced by Radioactive Ion Beams (RIBs) on the Radioactive Ion Beam Line in Lanzhou (RIBLL) at the Heavy-Ion Research Facility in Lanzhou (HIRFL). The disadvantages of broad beam profiles and limited intensities of the RIBs were overcome using large area detectors, two Parallel-Plate Avalanche Counters (PPACs), two double-sided silicon strip detector (DSSD) telescopes, incorporated with Monte Carlo simulations. The PPACs were used to determine the direction and position of the beam particles. The DSSD telescopes were used to measure scattered particles. Small corrections for the misalignment of detectors and the data normalization were made by assuming the pure Rutherford scattering at very forward angles. The method is suitable for the measurement of the cross-sections on heavy targets at low and intermediate energies, and it has been successfully applied to measure the angular distribution of elastic scattering of 7Be on Pb target at E lab = 17.9 MeV / u .

The experiments of two-alpha emission from Ne-17,Ne-18 excited levels were performed at the HIRFL-RIBLL facility of the Institute of Modern Physics, Lanzhou. The beams of Ne-17 at the energy of 49.9 MeV/u and Ne-18 at 51.8 MeV/u bombarded a Au-197 target to populate excited states of Ne-17,Ne-18 via Coulomb excitation. Complete kinematics measurements were achieved by the detectors of a silicon strip and CsI+PIN array. The experimental results combined with simple MC simulations show the characteristic of sequential two-alpha emission via O-14 excited states for Ne-18. The results of two-alpha emission from Ne-17 are preliminary and need further analyses.

Two-proton emissions from the excited states of 17,18Ne, 28P and 28,29S were investigated experimentally by the radioactive beams bombarding on the 197Au target via the Coulomb excitation. The complete-kinematics measurements were actualized by the stacks of silicon-strip detectors and CsI+PIN array detectors. The invariant mass of final systems as well as the relative momentum, opening angle, and relative energy of the two emitted protons was reconstructed under the framework of relativistic kinematics. Visible proton-proton correlations were observed in these systems. The mechanisms of two-proton emission were analyzed in a simple schematic model, in which the extreme decay modes like 2He cluster emission, three-body phase-space decay, and two-body sequential decay were taken into account. With the help of Monte-Carlo simulations, the two protons emitted from the 6.15 MeV excited state of 18Ne and the excited states in the energy region of 9.6–10.4 MeV of 29S, respectively, exhibited prominent features of 2He cluster decay while for the other cases, no obvious diproton emissions were observed.

The proton resonant properties in 18Ne, which determine the reaction rate of the key stellar 14O(α,p)17F reaction, have been studied by using a technique of proton resonant elastic scattering of 17F+p. A 4.22 MeV/nucleon 17F radioactive ion (RI) beam was produced via a projectile-fragmentation reaction, and separated by a Radioactive Ion Beam Line in Lanzhou (RIBLL). By bombarding a thick (CH2) n target, the energy spectra of the recoiled protons were measured by two ΔE-E silicon telescopes at the center-of-mass scattering angles of θ c.m.≈175°±5°, θ c.m.≈152°±8°, respectively. Several proton resonances in 18Ne were observed clearly. A further R-matrix analysis of the experimental data is under way to determine the resonant parameters. The present work reports the preliminary results briefly.

Fragment yields of projectile fragmentation reactions using primary beams of 36,40Ar at 50 MeV/nucleon on 64 Ni target have been measured. Fragment yields of different isotopes were obtained for Z ≥ 5 in RIBLL fragment seperator. We compare the extracted yields to the predictions of the empirical parametrization of fragmentation cross-sections(EPAX) and Statistical Abration-Ablation model(SAA) considering the RIBLL separator transmission rate. Isotope yield ratios between these 2 reactions were calculated, isoscaling parameters α and β, their dependence on fragment atomic number Z and neutron number N were calculated.

A series of experiments have been performed by complete kinematics measurements to study two-proton (2 p) correlated emission from the excited states of 17,18Ne and 28,29S via the Coulomb excitation by bombarding on 197Au target. 2p and residua coincident events were picked out under strict conditions. Visible p − p correlations were observed. It is shown that 2p can be emitted from the high-lying excited states. 2p halo may lead to 2p emission with large spectroscopy factor for the states close to or beyond the threshold.

High-spin states in 187Pt were studied via the 173Yb(18O, 4n) reaction. Rotational bands based on the νi13/2, ν7/2−[503], νi213/2νj, ν3/2−[512] and ν1/2−[521] configurations were observed, and interpreted within the framework of the cranked shell model. The TRS calculations show that the νi13/2 band has an appreciable negative γ deformation, and the negative-parity bands tend to have a near prolate shape with small positive γ values. Experimental values of B(M1)/B(E2) ratios have been extracted and compared with theoretical values from the semi-classical Donau and Frauendof approach, strongly suggesting a low frequency πh9/2 alignment in the ν7/2−[503] band.

Search for low-spin signature inversion in the πi13/2 ⊗ νi13/2 bands in odd-odd 182,184,186 Au has been conducted through the standard in-beam γ-spectroscopy techniques. The experiments for 182 Au and 186 Au have been performed in the Japan Atomic Energy Agency (JAEA) via the 152 Sm (35 Cl ,5 n )182 Au and 172 Yb (19 F ,5 n )186 Au reactions, respectively. A study of 184 Au has been made using a multi-detector array GASP in LNL, Italy, via the 159 Tb (29 Si ,4 n )184 Au reaction. The πi13/2 ⊗ νi13/2 bands in these three nuclei have been identified and extended up to high-spin states. In particular, the inter-band connection between the πi13/2 ⊗ νi13/2 band and the ground-state band in 184 Au has been established, leading to a firm spin-and-parity assignment for the πi13/2 ⊗ νi13/2 band. The low-spin signature inversion is found in the πi13/2 ⊗ νi13/2 bands in 182,184,186 Au according to our spin-assignment and the signature crossing observed at high-spin states.

Excited states in 188Tl have been studied experimentally using the 157Gd (35Cl, 4n) reaction at a beam energy of 170MeV. A rotational band built on the πh 9/2 ⊗ νi 13/2 configuration with oblate deformation has been established for 188Tl. Based on the structure systematics of the oblate πh 9/2 ⊗ νi 13/2 bands in the heavier odd-odd Tl nuclei, we have tentatively proposed spin values for the new band in 188Tl. The πh 9/2 ⊗ νi 13/2 oblate band in 188Tl shows low-spin signature inversion, and it can be interpreted qualitatively by the two-quasiparticle plus rotor model including a J-dependent p-n residual interaction.

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

Excited states in 190 Tl have been studied experimentally using the 160 Gd( 35 Cl, 5n) reaction, and resulted in the identification of a strongly coupled band based on the πh 9/2 ⊗ vi 13/2 configuration with oblate deformation. Combining with the results from the previous α-decay of 194 Bi, spin values have been proposed for the πh 9/2 ⊗ vi 13/2 oblate band in 190 Tl. This oblate band shows low-spin signature inversion. It is the first experimental observation of low-spin signature inversion for a band associated with the oblate πh 9/2 ⊗ vi 13/2 configuration.

High-spin states in 126Cs were populated in the reaction 116Cd(14N, 4n) at a beam energy of 65 MeV. About 50 new transitions were placed in a level scheme that consists of six rotational structures, three of which have been observed for the first time. The newly observed bands and a previously reported but uninterpreted band were assigned configurations based on their population, aligned angular momentum, energy signature splitting and B(M1)/B(E2) ratios (for the strongly coupled bands).

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.

The high-spin states of 157Yb have been studied via the 144Sm(16O, 3n) reaction 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 measured results of γ-γ coincidences, γ-ray anisotropies and DCO ratios, the level scheme for 157Yb was established. The shape co-existence and structural evolution of the νi 13/2 band with increasing angular momentum in 157Yb have been discussed. The systematics of the νi 13/2 bands in the N = 87 odd-A isotones have been compared.

A new isotope of Db has been produced via the reaction Am(Ne, 4n) at Elab = 118 MeV, and its half-life of 0.51± 0.16 s and α-decay energy of 9.47 MeV were determined in this work. The americium targets with thickness ranged from 0.7 to 1.0 mg/cm were prepared by molecular plating method through a single electrodeposition cycle. The reaction products were transported and collected using a helium-jet technique and a rotating wheel apparatus. The α decays of both the products and their daughter nuclides were detected by a series of Si(Au) surface barrier detectors arranged ingeniously. The identification of Db was performed based on the genetic relationship between the new activity and the known Lr established by α-recoiled milking measurement. The Qα value of Db derived from the present experiment is in good agreement with theoretical prediction.

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.

An isotope of the element 105 with mass number 259 has been produced via the reaction 241Am(22Ne, 4n)259Db at Elab = 118 MeV. The reaction products were transported and collected using the helium-jet technique and the rotating wheel apparatus. The α-decays of the products and their daughter nuclides were detected by a set of Si(Au) detectors arranged ingeniously. The Z and A of the nuclide have been unambiguously identified by the genetic relationship between the new activity and the known nuclide 255Lr established by α-recoiled milking measurement. The new nuclide 259Db has a half-life of 0.51±0.16 s and decays by alpha-particle emission of Eα = 9.47 MeV. Furthermore, the nuclide 258Db and its daughter 254Lr have also been clearly observed using the same projectile-target combination. Their half-lives and α-particle energies determined in this work are in agreement with previous known data, thus also proving the reliability of our assignment of 259Db.

High-spin states in 143Pm have been investigated via the 128Te(19F,4nγ)143Pm reaction using techniques of in-beam γ-spectroscopy. γ-ray singles, γ-γ coincidences, γ-ray anisotropies and DCO ratios have been measured. Based on these measurements, the level scheme of 143Pm has been extended up to an excitation energy of 10535.4 keV, including 48 new γ-rays deexciting 28 new levels. The yrast levels in 143Pm can be understood qualitatively in the framework of a weak-coupling model.

An effort has been made to search for the decoupled bands in odd-odd 174Re via the 159Tb(20Ne,5n γ)174Re reaction through excitation functions, K x-γ and γ-γ coincidence measurements. The doubly decoupled band and the semidecoupled one have been found in this work. Their quasiparticle configurations are proposed to be π1/2−[541] ⊗ν1/2−[521] and π1/2−[541] ⊗νi 13/2, respectively, according to the characteristics of band structures in this mass region. Another band with strongly coupled character is also reported.

High-spin states of 117Xe were investigated by means of in-beam γ-ray spectroscopic techniques via the reaction of 28Si bombarding a 92Mo target at beam energies of 100-120 MeV. A positive-parity rotational band decaying into the yrast negative-parity band by a series of enhanced E1 transitions was observed for the first time, implying the existence of octupole correlations in 117Xe. The B(E1) values increase with spin. The νd5/2 band was firmly established up to 27/2+ and the B(M1)/B(E2) ratios were extracted from the relative intensities of γ-rays in this band. The previously known νh11/2 and νg7/2 [413]5/2+α=−1/2 bands were confirmed and extended up to high spins and two bandcrossings are observed in the latter at ħω=0.33 and 0.44 MeV, respectively. The bandcrossings and configurations of these bands are discussed by TRS and CSM calculations. In a γ–γ–t measurement, the 11/2− and 7/2− levels were identified as two isomers with half-lives of 59.4±20 ns and 16.5±8.0 ns, respectively.

The high-spin states of {sup 198}Bi have been studied via the reaction {sup 187}Re({sup 16}O,5{ital n}){sup 198}Bi at {sup 16}O energies from 85 to 105 MeV. In-beam measurements of {gamma}-ray excitation functions, {gamma}-{gamma}-{ital t} coincidences, and {gamma}-ray angular distributions were carried out with 6 BGO(AC)HPGe detectors and one intrinsic Ge planar detector. A level scheme for {sup 198}Bi with 26 {gamma} rays was established for the first time, including a 15{sup +} isomer with a measured half-life of 8.0{plus_minus}3.6 ns. The level structure of {sup 198}Bi was qualitatively interpreted by using semiempirical methods. {copyright} {ital 1996 The American Physical Society.}

A new isotope (265)Bh was produced and identified at the Sector Focus Cyclotron of the Heavy Ion Research Facility in Lanzhou. This experiment was performed via the reaction of an Am-243 target with 168 MeV Mg-26 ions. Identification was made by observation of correlated alpha-particle decays between the new isotope (265)Bh and its (261)Db and Lr-257 daughter nuclei rising a set of rotating-wheels system. A total of 8 correlated decay events of (265)Bh and 4 decay events Of (264)Bh were observed. (265)Bh decays with a 0.94(-0.31)(+0.70) s half-life by emission of a-particles with an average energy of 9.24 +/- 0.05 MeV. The half-life and a decay energy of (265)Bh from this experiment are in agreement with theoretical predictions.

Near yrast positive-parity states of particle-hole nuclei around ${}^{100}$Sn have been studied and found mainly to be the coupling of ${g}_{9/2}$ valence-proton holes to the ${d}_{5/2}$ and ${g}_{7/2}$ valence-neutron particles. The much higher excitation energy for a stretched coupled state involving $\ensuremath{\nu}{g}_{7/2}$ rather than $\ensuremath{\nu}{d}_{5/2}$ indicates that level structures of particle-hole nuclei around ${}^{100}$Sn might be dominated by the $T=1$ channel of proton-neutron residual interaction. The near yrast states are compared with the results of shell model calculations in the model space of $\ensuremath{\pi}{({p}_{1/2},{g}_{9/2})}^{\ensuremath{-}1\ensuremath{-}\ensuremath{-}4}$ and $\ensuremath{\nu}{({d}_{5/2},{s}_{1/2},{d}_{3/2},{g}_{7/2},{h}_{11/2})}^{1\ensuremath{-}3}$ by using the dominant $T=1$ channel proton-neutron quadrupole interaction; and the reasonable agreement with each other gives indirect proof of it being responsible for level structures of particle-hole nuclei around ${}^{100}$Sn.

The breakup reactions of Cl-31 + C-12 at 44A MeV are investigated experimentally. The longitudinal momentum distribution of S-30 after one-proton removal from Cl-31 has been obtained. By assuming core plus a valence proton structure, the momentum distribution is studied using the few-body Glauber model. The calculation shows that the width of momentum distribution for a valence proton with l = 2 is consistent with the experimental data, which indicates a dominant d-wave component for the valence proton in Cl-31.

High-spin states in 101Pd have been investigated by means of in-beam γ-ray spectroscopic techniques via the 76Ge(28Si, 3n) reaction at beam energies of 85 and 95 MeV. The previously known d 5/2 and 1/2−[550] bands were extended to higher spins, and the unfavored signature branch of the 1/2−[550] band was built. The band crossings observed experimentally are explained by the alignment of g 9/2 protons. The band properties in 101Pd are compared with those in the neighboring nuclei and are discussed within the framework of the cranked shell model (CSM).

The stellar 14O (α, p) 17F reaction is thought to be one of the most important breakout reactions from the Hot CNO cycles into the rp-process in Type I X-ray bursters. In the present work, the properties of proton resonances in 18Ne have been investigated efficiently by utilizing a technique of proton resonant elastic scattering with a 17F radioactive-ion (RI) beam and a thick proton target. A 4.22 MeV/nucleon 17F RI beam, which was produced via a projectile-fragmentation reaction and experiencing a series of energy degradation, was separated by a Radioactive Ion Beam Line in Lanzhou (RIBLL) and bombarded a (CH2)n target. Energy spectra of the recoiled protons were measured by two sets of ΔE-E silicon telescope at center-of-mass scattering angles of θ c.m. ≈ 175° ± 5°, θ c.m. ≈ 152° ± 8°, respectively. Several proton resonances in 18Ne were observed, and their resonant parameters have been determined by an R-matrix analysis of the differential cross-sections. A doublet structure around 7.10 MeV has been identified and thought to be one state at 7.05 MeV (2+) and another one at 7.12 MeV (4+). The presently calculated total reaction rates of 14O (α, p) 17F are, at least, a factor of 1.2 ∼ 1.9 larger than the previous ones in a temperature region of 1.7 ∼ 3.0 GK mainly owing to the contribution from the 7.05 MeV (2+) state. This result implies that this breakout reaction may play a more important role than previously expected.

Two-{alpha} emission from high-lying excited states of {sup 18}Ne was studied by complete-kinematics measurements. The {sup 18}Ne beam at the energy of 51.8 MeV/u was bombarding a {sup 197}Au target to populate the excited states via Coulomb excitation. Products of two-{alpha} emission, {sup 10}C-{alpha}-{alpha}, were measured by an array of silicon strip detectors and a CsI + PIN telescope. With the help of Monte Carlo simulations, the experimental results show the characteristics of sequential two-{alpha} emission via {sup 14}O excited states. Sequential two-{alpha} and two-proton emissions from {sup 18}Ne via one-particle daughter states are compared and the distinction of the opening angles of these two modes originates from the difference of the mass ratio of emitted particles to daughter nuclei.

An experiment to study exotic two-proton emission from excited levels of the odd-$Z$ nucleus $^{28}\mathrm{P}$ was performed at the National Laboratory of Heavy Ion Research-Radioactive Ion Beam Line (HIRFL-RIBLL) facility. The projectile $^{28}\mathrm{P}$ at the energy of $46.5$ MeV/$u$ was bombarding a $^{197}\mathrm{Au}$ target to populate the excited states via Coulomb excitation. Complete-kinematics measurements were realized by the array of silicon strip detectors and the $\mathrm{CsI}+\mathrm{PIN}$ telescope. Two-proton events were selected and the relativistic-kinematics reconstruction was carried out. The spectrum of relative momentum and opening angle between two protons was deduced from Monte Carlo simulations. Experimental results show that two-proton emission from $^{28}\mathrm{P}$ excited states less than $17.0$ MeV is mainly two-body sequential emission or three-body simultaneous decay in phase space. The present simulations cannot distinguish these two decay modes. No obvious diproton emission was found.

An experiment of a $^{29}\mathrm{S}$ beam bombarding a $^{197}\mathrm{Au}$ target at an energy of 49.2 MeV/u has been performed to study the two-proton correlated emission from $^{29}\mathrm{S}$ excited states. Complete-kinematics measurements were carried out in the experiment. The relative momentum, opening angle, and relative energy of two protons, as well as the invariant mass of the final system, were deduced by relativistic-kinematics reconstruction. The $^{27}\mathrm{Si}$-$p\text{\ensuremath{-}}p$ coincident events were picked out under strict conditions and the phenomenon of $p\text{\ensuremath{-}}p$ correlations was observed among these events. The mechanisms of two-proton emission were analyzed in a simple schematic model, in which the extreme decay modes like $^{2}\mathrm{He}$ cluster emission, three-body phase-space decay, and two-body sequential emission were taken into account. Associated with the Monte Carlo simulations, the present results show that two protons emitted from the excited states between 9.6 MeV and 10.4 MeV exhibit the features of $^{2}\mathrm{He}$ cluster decay with a branching ratio of ${29}_{\ensuremath{-}11}^{+10}%$.

The high-spin states of 206At have been studied in the reaction 197Au (12C,3n) 206At at 12C energies from 60 to 80 MeV. In-beam measurements of γ-ray excitation functions, γ-γ-t coincidences, and γ-ray angular distributions were carried out with seven BGO(AC)HPGe detectors and one intrinsic Ge planar detector. A level scheme for 206At with 25 γ rays was established for the first time, including a 10− isomer with a measured half-life of 410 ± 80 ns. The level scheme of 206At consists of two disconnected cascades, probably corresponding to the proton excitations and the neutron-hole excitations, respectively.

The decay of 131Pm has been investigated by means of γ-ray spectroscopy. The 131Pm nuclei were produced by fusion-evaporation reaction of 106Cd(32S,3p4n) at the beam energy of 170 MeV. A helium-jet technique and a tape transport system were used to collect the activities and transfer them to a detecting position for X and γ rays measurement. Two γ rays of 185.0 and 220.0 keV were unambiguously identified to follow the β+ decay of 131Pm by results of X-γ and γ–γ coincidence. A growth-decay feature of the decay curve for 87.8 keV γ-ray of 131Nd confirmed the production of 131Pm nuclei. The half-life of 131Pm was measured to be 6.3 ± 0.8 s. A partial decay scheme of 131Pm is proposed on the basis of X-γ and γ–γ coincidence data in this experiment and the known structure information deduced from in-beam experiments of the daughter nucleus 131Nd.

High-spin states in $^{187}\mathrm{Pt}$ have been studied experimentally using the $^{173}\mathrm{Yb}$($^{18}\mathrm{O}$, $4n$) reaction at beam energies of 78 and 85 MeV. The previously known bands based on the $\ensuremath{\nu}{i}_{13/2},\ensuremath{\nu}7/{2}^{\ensuremath{-}}[503]$, and $\ensuremath{\nu}{i}_{13/2}^{2}\ensuremath{\nu}j$ configurations have been extended to high-spin states, and new rotational bands associated with the $\ensuremath{\nu}3/{2}^{\ensuremath{-}}[512]$ and $\ensuremath{\nu}1/{2}^{\ensuremath{-}}[521]$ Nilsson orbits have been identified. The total Routhian surface calculations indicate that the transitional nucleus $^{187}\mathrm{Pt}$ is very soft with respect to $\ensuremath{\beta}$ and $\ensuremath{\gamma}$ deformations. The band properties, such as level spacings, band crossing frequencies, alignment gains, and signature splittings, have been compared with the systematics observed in neighboring nuclei and have been interpreted within the framework of the cranked shell model. The rotational bands show different band crossing frequencies, which can be explained by the alignment either of ${i}_{13/2}$ neutrons or of ${h}_{9/2}$ protons. Importantly, evidence is presented for a $\ensuremath{\pi}{h}_{9/2}$ alignment at very low frequency in the $\ensuremath{\nu}7/{2}^{\ensuremath{-}}[503]$ band. The proton nature of the band crossing is strongly suggested by comparing the measured $B(M1;I\ensuremath{\rightarrow}I\ensuremath{-}1)/B(E2;I\ensuremath{\rightarrow}I\ensuremath{-}2)$ ratios with the theoretical values from the semiclassical D\"onau and Frauendof approach.

High spin states in 170Ta have been studied via 159Tb(16O,5nγ)170Ta reaction through excitation functions, K X-γ and γ-γ-t coincidence measurements. Three rotational bands have been identified among which one coupled band and an unfavored δI=2 E2 transition sequence are newly found in this work. The possible quasiparticle configurations of these bands are discussed.

Two low-lying isomeric states in 169Ta have been identified via 159Tb(16O, 6nγ)169Ta reaction. Their half-lives are measured to be 28 ± 5 ns for the 9/2- level and 17 ± 4 ns for the 5/2- level by using the delayed γ-γ coincidence method. These two isomeric states are considered to be the bandheads with 9/2-[514] and 1/2-[541] configurations, respectively. Possible neutron quasiparticle configuration for the ground state of 169W is discussed.

High-spin states in Tl-190 have been studied experimentally by using the Gd-160(Cl-35,5n) fusion-evaporation reaction at beam energies of 167 and 175 MeV. A rotational band built on the pi h(9/2)circle times nu i(13/2) configuration with oblate deformation has been established for Tl-190. Spin values are assigned by adopting the results from alpha-gamma decay work for Bi-194 found in the literature. With the configuration and spin-parity assignments, the low-spin signature inversion has been revealed for the pi h(9/2)circle times nu i(13/2) oblate band in Tl-190. It is the first experimental observation of low-spin signature inversion for a band associated with the oblate pi h(9/2)circle times nu i(13/2) configuration. The low-spin signature inversion for the oblate pi h(9/2)circle times nu i(13/2) band can be interpreted by the two-quasiparticle-plus-rotor model including a J-dependent p-n residual interaction.

High-spin states in Au-183 have been studied experimentally using the Tb-159(Si-29,5n)Au-183 reaction at a beam energy of 140 MeV. Three- or higherfold gamma-ray coincidences have been measured using the detector array of GASP. The level scheme of Au-183 was revised and extended. A rotational band proposed as the unfavored signature branch of the pii(13/2) band has been observed for Au-183. Interaction properties between the two negative-signature bands of the pih(9/2)-pif(7/2) system have been discussed for the light odd-A Au nuclei.

High-spin states in 198Bi were populated via the 187Re(16O, 5n) reaction. A partial level scheme for 198Bi was established for the first time, including a 15+ high-spin isomeric state with a measured half-life of 8.0 ± 3.6 ns. By comparing the level structure of 198Bi with that of the even-even core 198Pb, the configuration ν(i13/2)-2ν(p3/2)-1π(h9/2)1 was ascribed to this isomeric state.

High-spin states in doubly odd {sup 170}Re have been populated via the {sup 142}Nd({sup 32}S,p3n{gamma}) reaction at beam energies of 155 and 166 MeV. K X-{gamma} and {gamma}-{gamma} coincidences have been measured using a detector array consisting of 12 high-purity germanium detectors with BGO suppressors. A rotational band is identified and assigned to {sup 170}Re for the first time. This band is proposed to be built on the {pi}h{sub 11/2}x{nu}i{sub 13/2} two-quasiparticle configuration by comparing the band properties with known bands in neighboring nuclei and the cranked-shell model calculations.

High-spin level structure in Au-184 has been reinvestigated using the multidetector array of GASP via the Tb-159 (Si-29, 4ngamma)Au-184 reaction at a beam energy of 140 MeV. The ground-state band and the excited pii(13/2) circle times vi(13/2) 2-qp band have been extended up to lower and higher spin states. An upbend has been observed in the excited band at homegasimilar to0.25 MeV and is interpreted as resulting from a pair of pih(9/2) alignment. This low-frequency (pih(9/2))(2) alignment is supported by the measured B(M1)/B(E2) ratios and alignment properties in neighboring odd-A nuclei. The linking transitions between the two bands and to the ground state have been established leading to a firm spin-and-parity assignment for the pii(13/2) circle times vi(13/2) band in Au-184. This result provides strong evidence for the low-spin signature inversion in the pii(13/2) circle times vi(13/2) bands of odd-odd nuclei in the A similar to 180 mass region.

An in-beam gamma-ray spectroscopy experiment for Pm-142 has been performed via the Te-128(F-19,5n) reaction at beam energies of 75 MeV through 95 MeV. Excitation functions and gamma-gamma coincidences have been measured. Detailed analysis of gamma-gamma coincidence relationships leads to a revised high-spin level scheme for Pm-142. The pih(11/2) x nuh(11/2)(-1) multiplet in this nucleus has been identified and the discussion is based on a systematic of corresponding states in neighboring odd-odd nuclei. The previously known 67-mus isomer and associated decay gamma rays have been placed into the new level scheme. This long-lived isomer is proposed to be a four-hole state with predominantly the (pig(7/2)(-1)d(5/2)(-2) x nuh(11/2)(-1))(13-) configuration.

High-spin states in Au-179 have been studied experimentally using the Sm-149(Cl-35,5n) fusion-evaporation reaction at beam energies of 164-180 MeV. A rotational band built on the 1/2[660](i(13/2)) Nilsson orbital has been established for Au-179. Properties of the 1/2[660](i(13/2)) bands in the odd- A Au nuclei are discussed with an emphasis on the evolution of bandhead energy and deformation while changing neutron number.

High-spin states in ${}^{170}\mathrm{Ta}$ have been studied via ${}^{159}{\mathrm{T}\mathrm{b}(}^{16}\mathrm{O},5n\ensuremath{\gamma}{)}^{170}\mathrm{Ta}$ reaction through excitation functions, K x-\ensuremath{\gamma}, and $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}\ensuremath{-}t$ coincidence measurements. Three rotational bands have been identified which consist of two strongly coupled bands and a semidecoupled one. The quasiparticle configurations of these bands and the interpretation of experimental results are discussed based on the existing knowledge of neighboring odd-mass and odd-odd nuclei and in the framework of the cranked-shell model. Low-spin signature inversion in the $\ensuremath{\pi}{9/2}^{\ensuremath{-}}[514]\ensuremath{\bigotimes}\ensuremath{\nu}{5/2}^{+}[642]$ and $\ensuremath{\pi}{1/2}^{\ensuremath{-}}[541]\ensuremath{\bigotimes}\ensuremath{\nu}{5/2}^{+}[642]$ bands are discussed. A delay (reduction) of the band-crossing frequency is observed in the $\ensuremath{\pi}{1/2}^{\ensuremath{-}}[541]\ensuremath{\bigotimes}\ensuremath{\nu}{5/2}^{+}[642]$ $(\ensuremath{\pi}{5/2}^{+}[402]\ensuremath{\bigotimes}\ensuremath{\nu}{5/2}^{+}[642])$ band. This configuration-dependent crossing frequency is discussed in comparison with the AB crossing frequencies in the related bands of neighboring odd-Z isotopes.

Gamma rays with energies between 80 keV and 1500 keV produced by 133Ba and 152Eu standard sources are measured with the clover detector. Relative efficiencies and add-back factors are determined in both crystals and full clover modes. The add-back characteristics have been calculated using Monte-Carlo simulation code Geant4. The simulation and measurements agree very well.

High-spin states in 185Pt have been investigated using the 173Yb(16O, 4n) reaction at a beam energy of 90 MeV. The 7/2?[503] band in 185Pt is revised, and particularly the intra-band B(M1)/B(E2) ratios are deduced experimentally. Low-spin signature inversion is revealed in the 7/2?[503] band. The signature inversion can be interpreted if we assume configuration change in this band from the 7/2?[503] orbital to the 7/2?[514] orbital with increasing spin, which is supported by comparing the measured B(M1)/B(E2) ratios with the theoretical values from the semi-classical D?nau and Frauendorf approach.