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This contribution will report on the experimental work on the level structure of 168Dy. The experimental data have been taken as part of the EURICA decay spectroscopy campaign at RIBF, RIKEN in November 2014. In the experiment, a 238U primary beam is accelerated up to 345 MeV/u with an average intensity of 12 pnA. The nuclei of interest are produced by in-flight fission of 238U impinging on Be target with a thickness of 5 mm. The excited states of 168Dy have been populated through the decay from a newly identified isomeric state and via the β decay from 168Tb. In this contribution, scientific motivations, experimental procedure and some preliminary results for this study are presented.

Neutron-rich 160,161,162Sm isotopes have been populated at the RIBF, RIKEN via β first time. β-coincident γ rays were observed in all three isotopes including γ rays from the isomeric decay of 160Sm and 162Sm. The isomers in 160Sm and 162Sm have previously been observed but have been populated via β decay for the first time. The isomeric state in 162Sm is assigned a 4−v72+[ 633 ]⊗v12−[ 521 ]${4^ - }v{{7 \over 2}^ + }\left[ {633} \right] \otimes v{{1 \over 2}^ - }\left[ {521} \right]$ configuration based on the decay pattern. The level schemes of 160Sm and 162Sm are presented. The ground states in the parent nuclei 160Pm and 162Pm are both assigned a 6−v72+[633]⊗π52−[532]${6^ - }v{{7 \over 2}^ + }\left[ {633} \right] \otimes \pi {{5 \over 2}^ - }\left[ {532} \right]$ configuration based on the population of states in the daughter nuclei. Blocked BCS calculations were performed to further investigate the spin-parities of the ground states in 160Pm, 161Pm, and 162Pm, and the isomeric state in 162Sm

White light-emitting devices based on a donor-acceptor structure were fabricated in order to investigate the dependence of the optical properties of white light emission on the thickness variance (15, 20, 25, and 30 nm) of the emissive layer. The emissive layer has a donor-acceptor system with the host 4,4′,4′′-tris(carbasol-l-nyl)triphenylamine molecule doped with 4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl (BCzVBi) and 5,6,11,12-tetraphenylnaphtacene (Rubrene) molecules for blue and yellowish-green light activators, respectively. The characteristics of current density were analyzed by using a power function of applied field, J=σlEl+1 and the characteristic exponential function, J=J0(e(V-Vd)/V0-1). Through spectroscopic analysis, we obtained three physical quantities governing the device performance: 1) an effective conductivity, 2) a threshold potential, and 3) a characteristic potential barrier, which are associated with the trap-charge limited concentration in the bulk layer, the energy gap of the organic materials, and the barrier energy at the contact of electrodes, respectively. The electroluminescent spectra were studied quantitatively using a multi-peak fit with a Gaussian distribution for each electromagnetic transition. By this approach, we deduced the energy levels of the BCzVBi and Rubrene molecules that give leading information on the light emission mechanism and the energy transfer in the host-dopant system. [ABSTRACT FROM AUTHOR]

Blue organic light-emitting devices were fabricated with an activator of 4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl doped into the various host materials such as N,N′-bis-(1-naphtyl)-N,N′-diphenyl-1,1-biphenyl-4,4′-diamine; 4,4′-bis(2,2′-diphenylyinyl)-1,1′-biphenyl; 2-methyl-9,10-di(2-naphthyl) anthracene; and 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene to investigate optical properties of blue light emission in the host-dopant system. By spectroscopic analysis based on multi-peak fits to the emission spectra, we found that energy transfer between the host and dopant molecules have a strong correlation with key features; current density, luminous efficiency, and color index for the devices. Among the present dopant-host systems, the TPBi molecule was found to be the best molecule as a host material for our devices. In contrast, the DPVBi host induced a complex excimer (electromer) leading to a shoulder spectrum with a longer wavelength emission. It was found that the electromer significantly affects the optical and electrical properties of the device. [ABSTRACT FROM AUTHOR]

We report for the first time two distinctive features in the odd–odd nucleus 120 I: a pair of doublet bands and a high-spin isomer built on the π h 11 / 2 ν h 11 / 2 configuration. For producing the excited states of 120 I, a fusion-evaporation reaction 118 Sn( 6 Li, 4n) at E = l a b 48 MeV was employed. The beam was provided by the 14UD tandem accelerator of the Heavy Ion Accelerator Facility at the Australian National University. The observed doublet structure built on the positive-parity states is the first case and unique in isotopes with Z = 53 . The emerging properties are indicative of the known chiral characteristics, leading to a doubling of states for the π h 11 / 2 ν h 11 / 2 configuration. In contrast, the high-spin isomer with a half-life of 49(2) ns at spin-parity J π = 25 + can be explained in terms of a noncollective oblate structure with the full alignment of six valence nucleons outside the 114 Sn core: three protons ( g 7 / 2 ) 1 ( d 5 / 2 ) 1 ( h 11 / 2 ) 1 and three neutrons ( h 11 / 2 ) 3 . This is an outstanding case that reveals a pure single-particle structure consisting of equal numbers of valence protons and neutrons outside the semi-double shell closure of 114 Sn with Z = 50 and N = 64 . [ABSTRACT FROM AUTHOR]

This paper serves to give brief overviews of key issues in five case studies in engineering technology stand-alone project based courses within a standard scholastic framework. The courses were offered in a range of scenarios with significant international student participation. The subject material focused on optics, opto-electronics and electronics. Topics covered in this work include: issues with managing scope, issues with adapting to open ended problem solving, and, confusion between method based teaching and guided projects. The main purpose of this paper is to share findings on preparing and delivering project based courses that are developed within a pre-existing system of courses and with a pre-existing limit of facilities. [ABSTRACT FROM AUTHOR]

We report on the first β-decay data of 138Sb to 138Te isotopes beyond the doubly magic 132Sn. The parent nucleus was produced by the in-flight fission of a 238U beam on a 9Be target at 345 MeV per nucleon and measured at the BigRIPS separator of the Radioactive Isotope Beam Factory at RIKEN. By using advanced β-γ spectroscopy techniques, the half-life and the tentative spin-parity of 138Sb were measured to be 346(19) ms and (3-), respectively. In addition, we observed several low-lying non-yrast states in 138Te for the first time. Our data allowed us to rearrange the positions of the first 2+ and 4+ states in this nucleus and to construct the level scheme of 138Te in accordance with shell-model calculations. Additionally, we extend energy systematics of Te isotopes within neutron numbers 54 and 86. [ABSTRACT FROM AUTHOR]

New data have been obtained for 185Os following the 176Yb(13C,4n)185Os reaction, extending the pseudo-Nilsson &fracl;12-, -&frac;32- [&4tilde;&1tilde;&1tilde;] doublet structure and the &frac;72- [&4tilde;&0tilde;&4tilde; band to significantly higher spins. Gamma-ray branching ratio data have been analysed to obtain extensive B(M1) and B(E2) ratios for intraband and inter band transitions. The data are compared with particle-rotor calculations based on the pseudo-Nilsson potential and the Woods-Saxon potential. The results indicate that the pseudo-Nilsson approximation provides a good description of the &fracl;12-, -&frac;32-[&4tilde;&1tilde;&1tilde;] bands up to the first band crossing; the difference in magnitude between the model predictions and data for the &frac;72-[&4tilde;&0tilde;&4tilde;] band may be attributed to a lower deformation for the higher-K structure. [ABSTRACT FROM AUTHOR]

The band structures of the doubly-odd nucleus 116I have been studied by using in-beam γ-ray spectroscopy with the 103Rh(16O, 3n)116I reaction at an energy of Elab=80 MeV. The beam was provided by the 12UD tandem accelerator at the University of Tsukuba. Absolute excitation energies for the observed collective bands except for a band based on the π(h11/2)ν(g7/2) configuration have been definitely determined. The positive-parity rotational band based on the π(h11/2)ν(h11/2) configuration is built on the 8+ level at 874.3 keV and exhibits a spin inversion below I=14ℏ. A new vibration-like band built on the 8− level at 468.5 keV has been identified and can be interpreted as resulting from the π(g7/2)ν(h11/2) configuration coupled to the Te core vibration. A negative-parity band built on the 14− level at 2547.6 keV shows a vibration-like structure and terminates its collectivity at the 24− level at 6215.0 keV. The total Routhian surface calculations suggest a noncollective oblate state with β2=0.182 and γ=60° based on a fully aligned six-quasiparticle, π[h11/2(g7/2)2]ν[g7/2(h11/2)2], configuration for this 24− level. The excitation energy of the 7− isomer with T1/2=3.27 μs was found to be at 430.4 keV. [Copyright &y& Elsevier]

The excited states of the doubly-odd nucleus 118I were investigated by using in-beam gamma-ray spectroscopy with the 103Rh (18O, 3n) 118I reaction at an energy of 85 MeV. The beam was provided by the 12UD tandem accelerator at the University of Tsukuba. Several collective bands were identified and their excitation energies were definitely established. The positive-parity collective bands based on the πh11/2νh11/2 configuration and the negative-parity bands based on the πh11/2νg7/2 configuration were newly assigned. An inversion between the favored and unfavored states in the πh11/2νh11/2 band was observed below I=17.5ℏ. The excitation energy of the 7− isomer with T1/2=8.5 m was found to be at 188.8 keV. [Copyright &y& Elsevier]

Excited states of the 119Xe nucleus have been studied by using in-beam γ-ray spectroscopy with the 107Ag ( 16O, p3n) 119Xe fusion-evaporation reaction at a beam energy of 85 MeV. The level scheme of 119Xe has been derived from γ-γ coincidence and γ-γ angular correlation analyses. We have, for the first time, established the second negative-parity favored and unfavored states built on the 11/2- state, namely the yrare rotational bands in 119Xe. In contrast to the behavior of the yrast bands where the favored states are lying lower in energy, the yrare favored states were observed to lie above the unfavored band. Such a signature inversion in 119Xe is changed to be normal at I = 12?. [ABSTRACT FROM AUTHOR]

High-spin states in 117I have been studied via the 103Rh(18O, 4n) reaction at a beam energy of 85 MeV. Many deformed rotational bands built on the proton h11/2, g7/2, and g9/2 orbitals have been identified. Among them, an unfavoured rotational band and a quasi-gamma band based on the h11/2 state have been newly observed. Moreover, positive-parity states above Iπ= 35/2+ reported in the previous work have been rearranged. Several energetically favoured states have been assigned to noncollective oblate states based on various quasiparticle configurations with β2≈ 0.18–0.19 and γ= 60°. [ABSTRACT FROM AUTHOR]

High-spin states of the 115Te were studied by in-beam spectroscopy with the 89Y (29Si, p2n) fusion-evaporation reaction at a beam energy of 108 MeV. γ−γ coincidence and γ−γ angular correlation analyses were employed for determining the level scheme of 115Te. We have identified two vibrational-like bands built on the νh11/2 and νg7/2 quasiparticle states and the noncollective oblate states from the full alignment of quasiparticle configurations. In addition, a regular ΔI = 2 sequence with positive-parity was found for the first time in odd-A Te nuclei. This sequence is interpreted as a deformed structure resulting from three-quasiparticle alignment having the [π(g7/2, h11/2) ⊗ ν(h11/2)] configuration. Calculations of total Routhian surfaces and cranked shell model were performed and were used for assigning quasiparticle configurations to the states in 115Te. [ABSTRACT FROM AUTHOR]

High-spin states in 121Xe have been studied via the 109Ag (16O, p3n) 121Xe reaction at a beam energy of 80 MeV. Several rotational bands based on one- and three-quasiparticle excitations have been established. Among them, an unfavoured yrare rotational band with unfavoured signature has been newly identified. [ABSTRACT FROM AUTHOR]

The level structure of the odd-odd iodine nucleus 122I has been studied by the 120Sn(7Li, 5n) 122I reaction at Elab = 58 MeV. Two chopped beams from the 14UD (Unit Doubled) tandem heavy-ion accelerator at the Australian National University were used; one was a nanosecond (ns) pulsed-beam with separation of 1.7 microseconds (μs) and the second one was a 60-μs beam separated by 880 μs. Through in-beam and out-of-beam γ-ray spectroscopy, the complex proton-neutron multiplet states, including isomers with half-lives of a few tens of ns to a few tens of μs, have been identified. Collective states based on the proton h11/2 orbital exhibit two kinds of structure depending upon the coupled neutron orbital: a quadrupole vibration when involving the h11/2 orbital and a γ-soft deformed rotation when involving the g7/2 orbital. With spherical shell model and deformed shell-model calculations, the observed level structures are explained. [ABSTRACT FROM AUTHOR]

High-spin states of odd-odd 168Lu were observed up to 18ħ for the first time using the 159Tb(13C, 4nγ)168Lu reaction at E13C= 58.5 MeV. γ-γ coincidence, Eγ singles, excitation function, and the DCO ratios were measured. Two rotational bands with signature splitting were populated, among which the lower-energy band is identified as π 7/2+[404] ⊗ν 5/2+[642] in view of alignment and energy systematics. [ABSTRACT FROM AUTHOR]

We report new data on the 136Sb 6- yrast isomer with T1/2 = 489(40) ns and πg17/2 × νf37/2 configuration, populated in the projectile fission of 238U on a 9Be target. The analysis confirms the lifetime, providing a good accuracy measurement. In addition, the decay of the isomer to the ground state is newly suggested. Our result for the isomeric decay scheme is in a good agreement with shell-model calculations. [ABSTRACT FROM AUTHOR]

A correction to the article "New decay scheme of the 51136Sb85 6- isomer" that was published in the August 10, 2015 issue is presented.

In this article we report on the first spectroscopic information on 14051Sb89 and the observation of an isomer in this nucleus with T1/2 = 41(8) μs. It is located in close proximity to 140Sn for N = 90, where the vf7/2 orbit is completely filled. The possible origin of the isomeric state is a πg7/21 × vf7/2-1 coupling configuration, resulting in a (6-) or (7-) spin-parity. This is likely caused by an inversion of the πg7/2 and πd5/2 orbitals at N = 89. The existence of such an isomer far from stability is discussed extensively in the context of shell-model calculations and compared to results from mean-field calculations performed using a deformedWoods-Saxon potential. Both approaches suggest the observation of a single-particle excitation mode at an extreme neutron number. [ABSTRACT FROM AUTHOR]

Background: The properties of resonances in 26Si are important to better constrain the 25Al(p,γ)26Si reaction rate relevant to the synthesis of galactic 26Algs and energy generation in explosive stellar environment at higher temperature. Purpose: 21Al + p elastic scattering was measured to further constrain and investigate disagreements in resonance parameters for the high-lying excited states of 26Si with high statistics and without background contamination within the target. Methods: The experiment was performed by bombarding a thick H2 target with an 25Al radioactive ion beam. The resonances at excitation energies of 6.6-8.3 MeV in the 26Si compound nucleus were studied at the low-energy radioactive-ion beam facility CRIB (Center for Nuclear Study Radioactive Ion Beam separator) at the University of Tokyo. Results: Six resonant states were observed and their resonance parameters were extracted by an R-matrix analysis. Our resonance parameters for two levels are in good agreement with the results of previous studies, while for four others, excitation energy, proton partial width, and spin-parity assignment disagree with the results of recent study via elastic scattering of 25Al + p. Conclusion: The parameters of resonant states in 26Si determined in the present work for the 25Al(p,γ)26Si reaction rate are consistent with that of the previous result, solving spin-parity assignment discrepancies between experiments, relevant at higher temperatures. [ABSTRACT FROM AUTHOR]

Proton resonant states in 27P were studied by the resonant elastic scattering of 26Si + p with a 26Si radioactive ion beam bombarding a thick H2 gas target with the inverse kinematics method. The properties of these resonance states are important to better constrain the production rates of the 26Si(p,γ)27P reaction. This is one of the astrophysically important reactions needed to understand proton-rich nucleosynthesis such as the galactic production of 26Al and energy generation in explosive stellar environments. Although there are recent studies on the resonant structure in 27P, large uncertainties remain, and only a few levels are known. In this work, resonant states were observed over the excitation energies range of 2.3 to 3.8 MeV with high statistics and without background contamination within the target. The resonance parameters were extracted by an R-matrix analysis of the excitation function. The 26Si(p,γ )27P stellar reaction rate has been evaluated, including high-lying resonances found in this work. [ABSTRACT FROM AUTHOR]

The β-decay half-lives of 94 neutron-rich nuclei ^{144-151}Cs, ^{146-154}Ba, ^{148-156}La, ^{150-158}Ce, ^{153-160}Pr, ^{156-162}Nd, ^{159-163}Pm, ^{160-166}Sm, ^{161-168}Eu, ^{165-170}Gd, ^{166-172}Tb, ^{169-173}Dy, ^{172-175}Ho, and two isomeric states ^{174m}Er, ^{172m}Dy were measured at the Radioactive Isotope Beam Factory, providing a new experimental basis to test theoretical models. Strikingly large drops of β-decay half-lives are observed at neutron-number N=97 for _{58}Ce, _{59}Pr, _{60}Nd, and _{62}Sm, and N=105 for _{63}Eu, _{64}Gd, _{65}Tb, and _{66}Dy. Features in the data mirror the interplay between pairing effects and microscopic structure. r-process network calculations performed for a range of mass models and astrophysical conditions show that the 57 half-lives measured for the first time play an important role in shaping the abundance pattern of rare-earth elements in the solar system.

Excited states in the N=102 isotones 166Gd and 164Sm have been observed following isomeric decay for the first time at RIBF, RIKEN. The half-lives of the isomeric states have been measured to be 950(60) and 600(140) ns for 166Gd and 164Sm, respectively. Based on the decay patterns and potential energy surface calculations, including β6 deformation, a spin and parity of 6- has been assigned to the isomeric states in both nuclei. Collective observables are discussed in light of the systematics of the region, giving insight into nuclear shape evolution. The decrease in the ground-band energies of 166Gd and 164Sm (N=102) compared to 164Gd and 162Sm (N=100), respectively, presents evidence for the predicted deformed shell closure at N=100.

A new isomer with a half-life of 23.0(8) ms has been identified at 2406 keV in (126)Pd and is proposed to have a spin and parity of 10(+) with a maximally aligned configuration comprising two neutron holes in the 1h(11/2) orbit. In addition to an internal-decay branch through a hindered electric octupole transition, β decay from the long-lived isomer was observed to populate excited states at high spins in (126)Ag. The smaller energy difference between the 10(+) and 7(-) isomers in (126)Pd than in the heavier N=80 isotones can be interpreted as being ascribed to the monopole shift of the 1h(11/2) neutron orbit. The effects of the monopole interaction on the evolution of single-neutron energies below (132)Sn are discussed in terms of the central and tensor forces.

The level structures of the very neutron-rich nuclei 128Pd and 126Pd have been investigated for the first time. In the r-process waiting-point nucleus 128Pd, a new isomer with a half-life of 5.8(8) μs is proposed to have a spin and parity of 8(+) and is associated with a maximally aligned configuration arising from the g(9/2) proton subshell with seniority υ=2. For 126Pd, two new isomers have been identified with half-lives of 0.33(4) and 0.44(3) μs. The yrast 2(+) energy is much higher in 128Pd than in 126Pd, while the level sequence below the 8(+) isomer in 128Pd is similar to that in the N=82 isotone 130Cd. The electric quadrupole transition that depopulates the 8(+) isomer in 128Pd is more hindered than the corresponding transition in 130Cd, as expected in the seniority scheme for a semimagic, spherical nucleus. These experimental findings indicate that the shell closure at the neutron number N=82 is fairly robust in the neutron-rich Pd isotopes.