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The giant dipole resonance (GDR) in $^{6}\mathrm{Li}$ was investigated via the $^{6}\mathrm{Li}(\ensuremath{\gamma},xn)$ reactions by using quasi-mono-energy $\ensuremath{\gamma}$ rays in an energy range from 4.9 to 53.6 MeV. The $\ensuremath{\gamma}$ rays were generated via Compton backscattering of Nd laser photons with relativistic energy electrons in an electron storage ring, NewSUBARU. The energy resolution in a full width at half maximum of $\ensuremath{\gamma}$ ray was simulated to be $5%$ at 50 MeV. Photoneutrons were detected with a $4\ensuremath{\pi}$-type neutron detector consisting of 41 $^{3}\mathrm{He}$-gas proportional counters. The $(\ensuremath{\gamma},n)$ cross sections were dominant, while the $(\ensuremath{\gamma},2n)$ and $(\ensuremath{\gamma},3n)$ cross sections were negligibly small. The energy integral of photoneutron cross sections up to 53.6 MeV was 59 $\mathrm{MeV}\phantom{\rule{0.16em}{0ex}}\mathrm{mb}$, which exhausted $65%$ of the Thomas-Reiche-Kuhn sum rule. The GDR in $^{6}\mathrm{Li}$ was found to consist of mainly two components. The peak energy and the width for the low-energy component were ${E}_{r}=12\ifmmode\pm\else\textpm\fi{}1\phantom{\rule{0.28em}{0ex}}\mathrm{MeV}$ and $\mathrm{\ensuremath{\Gamma}}=21\ifmmode\pm\else\textpm\fi{}2\phantom{\rule{0.28em}{0ex}}\mathrm{MeV}$. Those for the high-energy component were ${E}_{r}=33\ifmmode\pm\else\textpm\fi{}2\phantom{\rule{0.28em}{0ex}}\mathrm{MeV}$ and $\mathrm{\ensuremath{\Gamma}}=30\ifmmode\pm\else\textpm\fi{}2$ MeV. The low-energy component corresponded to the GDR in $^{6}\mathrm{Li}$. The high-energy component was inferred to be the GDR owing to an $\ensuremath{\alpha}$-cluster excitation in $^{6}\mathrm{Li}$. The existence of this component was recently proposed and was suggested by the experimental studies of the $(p,{p}^{\ensuremath{'}})$, $(^{3}\mathrm{He},t)$, and $(^{7}\mathrm{Li},^{7}\mathrm{Be})$ reactions. The observed resonance shape of the high-energy component was well reproduced by modifying the GDR shape of a theoretical prediction for $^{4}\mathrm{He}$ at ${E}_{r}=26\phantom{\rule{0.28em}{0ex}}\mathrm{MeV}$ with $\mathrm{\ensuremath{\Gamma}}=20\phantom{\rule{0.28em}{0ex}}\mathrm{MeV}$; with increasing the excitation energy by 7 MeV ($Q$ value was more negative), widening the width by $1.5\ifmmode\pm\else\textpm\fi{}0.1$ times, and decreasing a peak height by $0.29\ifmmode\pm\else\textpm\fi{}0.02$ times. As a result, the magnitude of the energy integral of the cross sections for the high-energy component observed in the present work was $0.86\ifmmode\pm\else\textpm\fi{}0.06$ times that in the theoretical prediction of the $^{4}\mathrm{He}(\ensuremath{\gamma},n)$ reaction. It is a well-known fact that a frequency of a vibrating system is inversely proportional to the size of the system. We suggest that in excitation of the $\ensuremath{\alpha}$ cluster in $^{6}\mathrm{Li}$, the mass of the $\ensuremath{\alpha}$ cluster increases by $7\ifmmode\pm\else\textpm\fi{}2\phantom{\rule{0.28em}{0ex}}\mathrm{MeV}$, the size of the $\ensuremath{\alpha}$ cluster in $^{6}\mathrm{Li}$ is smaller than that of the free $^{4}\mathrm{He}$ by $\ensuremath{\sim}20%$, and the width of the GDR is broader than that of $^{4}\mathrm{He}$ by 1.5 times owing to the nuclear medium effect.

We measured pulse-height spectra of 16.7 MeV laser-Compton scattering photons with a 6 in.×5 in. NaI(Tl) detector for blank and three lead materials of 75.8, 50.9, and 25.9% transmissions at the NewSUBARU facility to investigate how the original Poisson distribution of the pulsed photons is modified after passing through thick-target materials. We present a well-prescribed method of determining the number of incident photons within 3.5% accuracy based on the response of the NaI(Tl) detector to the pulsed photon beams.

Photoneutron cross section measurements were made for Au in the entire energy range of the (γ,n) channel based on a direct neutron counting with quasi-monochromatic γ-rays produced in inverse Compton scattering of laser photons with relativistic electrons. The data were analyzed by a least-squares method to deduce photoneutron cross sections. The analysis significantly reduced experimental uncertainties compared with those resulting from the photon difference method. The result is compared with the previous data by direct neutron counting with γ-rays produced in positron annihilation in flight and by photoactivation with bremsstrahlung. The present data are in good agreement with the previous data near the neutron threshold, while there remain some discrepancies between the present and the previous data above 10 MeV.

Ratios of equilibrium charge-state yields for singly to doubly ionized He-3 ions at an energy of 420 MeV were measured using the Grand Raiden magnetic spectrometer at RCNP. Targets with atomic numbers of 6, 12, 28, 40, 50 and 82 were used. It is found that theoretical calculations for atomic electron-capture and stripping cross sections, which have been successful in describing the data up to beam energies of 200 MeV, are also applicable at this higher energy. However, where at the lower energies the stripping cross sections were calculated with a combination of models by Bohr and Gillespie, the best description of the data at E(He-3) = 420 MeV is obtained when using only the model by Gillespie. The experimental results are also compared with calculations using the code CHARGE, originally developed for fast, heavy (Z > 29) projectiles, to test the extrapolation to low-Z projectiles. It is found that the code underestimates the production of singly-charged He-3 ions, in particular for heavier target nuclei. (c) 2007 Elsevier B.V. All rights reserved.

A proposal is presented on the polarized 3 He ion source based on the spin-exchange collisions of the low-energy 3 He + ion with polarized alkali-metal atoms (Rb) which are optically pumped under the strong magnetic field. To transfer the electron polarization of 3 He + ion to the 3 He nucleus, we offer to use the Sona transition based on a non-adiabatic transition method. For efficiently ionizing 3 He + ion to form 3 He 2+ ion, 3 He + ion is stripped with a gas/foil stripper after accelerating 3 He + . As a compact ionizer for polarized 3 He + ions, an EBIS (Electron Beam Ion Source) ionizer operated with a high magnetic field is also proposed.

Trinucleon molecular structures in 6He and 6Be were investigated by using the 6Li(7Li, 7Be)6He reaction at 455 MeV and 6Li(3He, t)6Be reaction at 450 MeV, respectively. Binary decays into t + t from a broad state at Ex=18.0±1.0 MeV in 6He and into 3He + 3He from one at Ex=18.0±1.2 MeV in 6Be, respectively, were observed by measuring trinucleon cluster decays in coincidence with reaction particles. The branching ratios for binary decay were estimated to be about 0.7 for 6He and 6Be. These large branching ratios show that a trinucleon cluster state exists as an isobaric partner around Ex=18 MeV in 6He and 6Be.

New α-ray beams at synchrotron radiation facilities will give us unprecedented opportunities to study photonuclear reactions of astrophysical interest. Konan University and the Universite Libre de Bruxelles launch a 5-year project, starting in 2004, of constructing ari extended NACRE compilation in which photonuclear reactions obtained within a dedicated international effort will be included. © 2004 Elsevier B.V. All rights reserved.

The excitation and subsequent decay by proton emission of the isovector spin-flip giant monopole resonance are studied via the Pb-208 (He-3, t) reaction at 410 MeV. In the tritonsingles spectrum 60 +/- 5% of the non-energy-weighted sum-rule strength for this 2hw resonance is found in the region 29

Tri-nucleon cluster-structures in 6 Li were investigated by using the 7 Li( 3 He,α) reaction at 450 MeV and at θ L = 0° . A binary decay into t+ 3 He from a broad peak at E x = 21 MeV was observed. The branching ratio for the binary decay was estimated to be 0.8±0.2. From the measured angular correlations and the analysis of the spectral shape by using the Breit-Wigner formula, the peak was identified to be composed of two tri-nucleon cluster-states (t+ 3 He) of the 1 P -state at E x = 18MeV with a width (FWHM) of 5 MeV and the 3 P -state at E x = 22MeV with a width of 8 MeV.

We discuss the properties of γ beams produced by Compton back-scattering of laser light from relativistic electrons at AIST and SPring-8 and their applications to nuclear astrophysics experiments.

Laser-electron photon beams (LEPBs) in the MeV region have been produced in head-on collisions between relativistic electrons and laser photons at AIST. The LEPB is quasi-monochromatic and energy-variable naturally with 100% linear polarization. Photoneutron cross sections were measured for 9Be and 181Ta with the LEPB. The data are discussed in the context of nuclear astrophysics.

Electric dipole (E1) reduced transition probability B(E1) of 90Zr was obtained by the inelastic proton scattering near 0 degrees using a 295 MeV proton beam and multipole decomposition analysis of the angular distribution by the distorted-wave Born approximation with the Hartree-Fock plus random-phase approximation model and inclusion of El Coulomb excitation, and the E1 strength of the pygmy dipole resonance was found in the vicinity of the neutron threshold in the low-energy tail of the giant dipole resonance. Using the data, we plan to determine the precise dipole polarizability αD which is defined as an inversely energy-weighted sum value of the elecrric dipole strength. The dipole polarizability is expected to constrain the symmetry energy term of the neutron matter equation of state. Thus systematical measurement of the dipole polarizability is important.

The relaxation rates of the polarized rubidium (Rb) vapor were measured by using a chopped pumping laser to investigate the depolarization mechanism of a high density Rb vapor in a strong magnetic field. The measurement was carried out in a range of the magnetic field from 1 to 5 T and the Rb cell temperature from 90 to 130 °C which corresponds to the Rb vapor density from 0.2 to 2.0×10 13 at./cm 3 . The position dependence of the relaxation rates was also measured along the Rb cell axis. The experimental results showed that two components, i.e. a fast component with the relaxation rate of ∼ 65 ms −1 and a slow component with the relaxation rate of ∼ 1 ms −1 contribute. The observed relaxation rates were analyzed by the wall relaxation model, the effusion model and the radiation trapping model. It was found that the slow component was well explained by the wall relaxation and the effusion effect. On the other hand, the fast component is due to a formation of the localized Rb polarization around the pumping laser by a radiation trapping effect and a subsequent relaxation process due to an effusion.

We investigated the spatial distribution of a polarization in 3He beam expected from a novel polarized 3He ion source based on electron pumping, i.e., multiple electron capture and stripping collisions of an incident fast 3He+ ion with a polarized Rb vapor in a strong axial magnetic field. For this purpose, a Monte Carlo simulation was carried out for 19 keV 3He+ ions with varying Rb vapor thickness, magnetic field, and beam emittance. The calculated results showed a distribution of the 3He polarization that we call a “polarization hole”, which has a low polarization area around the beam axis. The parameters characterizing the polarization hole, i.e., the polarization and radius of the hole, were found to depend on the Rb vapor thickness, the magnetic field, the beam size, and the angular divergence of the initial beam. These parameters were successfully reproduced with analytical functions deduced from a probability density function prescription. This provides a powerful tool to treat complex phenomena of multiple collisions in strong magnetic fields without performing time-consuming Monte Carlo calculations.

A candidate for a soft dipole resonance, a dipole oscillation mode between a core cluster and a neutron skin, was observed at ${E}_{x}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}4\ifmmode\pm\else\textpm\fi{}1\mathrm{MeV}$ and with a width of $4\ifmmode\pm\else\textpm\fi{}1\mathrm{MeV}$ in ${}^{6}\mathrm{He}$ via the ${}^{6}\mathrm{Li}({}^{7}\mathrm{Li},{}^{7}\mathrm{Be})$ reaction at an incident energy of $65A\phantom{\rule{0ex}{0ex}}\mathrm{MeV}$ and forward scattering angles including $0\ifmmode^\circ\else\textdegree\fi{}$. Its cross section is deduced to be $\ensuremath{\sigma}(0\ifmmode^\circ\else\textdegree\fi{})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.9\ifmmode\pm\else\textpm\fi{}0.2\mathrm{mb}/\mathrm{sr}$. This value is comparable to that of the giant dipole resonance simultaneously measured.

The spin-exchange cross-section, σ se, was measured for a 6.33 keV/amu 3He+ ion incident on a polarized Rb atom. The result is σ se = −0.26 +0.27 × 10−15 cm2, which is unexpectedly an order of magnitude smaller than the theoretical value σ se = 5.9 × 10−15 cm2 evaluated by the semiclassical impact parameter method assuming formation of a single molecular state.

A He-3(+) beam with nuclear polarization was produced by passing a fast He-3(+)-ion beam through a thick polarized Rb vapor target in a strong magnetic field. Observed polarization transfer coefficients as a function of the Rb vapor thickness are qualitatively explained by an electron pumping model based on multiple processes of electron capture and stripping. The experimentally obtained polarization and beam current for the He-3(+) beam were, respectively, 0.07 and 2 mu A for a Rb polarization of 0.2. [S1050-2947(99)51111-6].

For a selective excitation of spin-flip strength, ( 6 Li, 6 He) reactions can be a useful tool, because: a) 6 Li and 6 He have ground-state spin and parity values J π = 1 + and 0 + , respectively; b) 6 He has no particle-stable excited state, thus effects from ejectile excitation can be avoided. The ( 6 Li, 6 He) experiments were performed at 100 MeV/nucleon, at which incident energy the reaction is expected to be single-step dominant. Through the analysis of the good-resolution ( 6 Li, 6 He) data on 13 C, 26 Mg, 27 Al and 58 Ni targets, the evidence for a proportional relationship between 0° cross sections and the corresponding Gamow-Teller transition strengths is examined. Suppression of non-spin flip excitations is discussed based on the hindrance of the excitation of the isobaric analog state.

The isovector electric monopole resonance (IVMR) was studied by the ${}^{60}\mathrm{Ni}{(}^{7}\mathrm{Li}{,}^{7}\mathrm{Be}{)}^{60}\mathrm{Co}$ reaction at 65A MeV and at forward scattering angles including zero degrees. We confirmed the existence of the IVMR at an excitation energy of $20\ifmmode\pm\else\textpm\fi{}2\mathrm{MeV}$ with a width of $10\ifmmode\pm\else\textpm\fi{}2\mathrm{MeV}$ in ${}^{60}\mathrm{Co}$, which is an analog of the ${T}_{0}+1$ isospin component of the IVMR estimated at ${E}_{x}\ensuremath{\approx}31\mathrm{MeV}$ in ${}^{60}\mathrm{Ni}$. The result presently obtained is consistent with previous results using the pion charge-exchange reaction.

Strong forward-backward asymmetries were found in the recent α — t coincidence measurement of Coulomb breakup of 42 MeV- 7 Li via continuum states. The competition between E1 and E2 multipolarities and higher order effects in Coulomb excitation were investigated by solving the time-dependent Schrodinger equation. It is shown that higher order effects are an essential ingredient to the observed large asymmetries. The relevant reaction mechanism is discussed.

Delayed nature associated with the quantum tunnelling effect was found for non-resonant break-up of through the Gamow energy region. This delayed nature is discussed in the astrophysical context of the Coulomb dissociation method; post Coulomb acceleration and its effect on the energy dependence of the cross sections.

A novel type of polarized 3He ion source based on “electron pumping” was recently proposed. This ion source requires multiple electron capture and stripping collisions of 3He+ ions with polarized alkali atoms under a strong magnetic field (2–3 T). Since these processes may induce a serious increase in the emittance and reduction of polarized beam intensity, we investigated them in detail by using the Monte Carlo simulation. It was found that there is (1) increase in the emittance results not from angular broadening but from a beam size enlargement, (2) the phenomena under magnetic field B are simplified by a collisionless phenomenon under a weaker magnetic field (effective magnetic field) Beff defined by Beff≃(λ+0/(λ+0+λ0+))B, where λ+0 and λ0+ are mean free paths for 3He+ ions and 3He0 atoms traveling in the alkali vapor.

A γ-ray detector system “NYMPHS” was built for 7Be-γ coincidence measurements to separate (7Li, 7Beg.s.) and (7Li, 7Be0.43MeV) channels in the (7Li, 7Be) reaction at intermediate energies. NYMPHS is composed of 22 GSO scintillators, each with a volume of about 30 cm3. A typical energy resolution was about 9% at Eγ = 0.66 MeV. The absolute detection efficiency of NYMPHS was 0.200 ± 0.005 for the 0.43 MeV 7Be γ-ray. NYMPHS combined with a magnetic spectrograph showed good performance for 7Be-γ coincidence measurements in the (7Li, 7Be) reactions on 12C and 90Zr targets at EL = 65A MeV.

The ( 7 Li, 7 Be) reaction was found to be used to separate ΔS = 0 and ΔS = 1 transitions through the coincidence measurement of the γ-ray from deexcitation of the 0.43 MeV state of 7 Be at an incident energy of 65 A MeV on 6 Li, 7 Li, 12 C and 90 Zr nuclei. The reaction was shown to proceed predominantly via one-step reaction process. Predominance of one-step process means utility for derivation of spin-flip and non spin-flip strengths for isovector excitations in medium heavy nuclei at intermediate incident energies. The relative nuclear spin-strength P sf was deduced for isovector excitations.

The method of Coulomb breakup was investigated used to extract absolute astrophysical S-factors for primordial 7Li synthesis. The method is discussed for the breakup of 42 MeV-7Li through astrophysical continuum states with emphasis on the amplification factor, nuclear breakup contribution and Coulomb reacceleration.

We constructed a new polarized 3 He ion source in order to establish a method of principle of “electron pumping” and experimentally prove its validity. Electron pumping utilizes multiple electron capture and stripping collisions of 3 He + with rubidium atoms whose vapor thickness is much thicker than that used in an ordinary optical pumping polarized ion source. Special care was paid in the design of a rubidium vapor cell, a pumping laser and a beam transport system. We present details of the device and report the present status of the development.

Coincidence measurements of α- 12 C pairs collinearly emitted in the breakup of 30 MeV/u- 16 O incident on 208 Pb and 120 Sn were performed with a two detector system set up along the focal plane of a magnetic spectrograph. Double differential cross sections for sequential breakup via the 2 2 + and 2 3 + states in 16 O were analyzed within the framework of coupled-channels (CC) calculations which incorporated microscopic α- 12 C cluster model wave functions for bound and unbound states of 16 O. The experimental data are satisfactorily reproduced by the CC calculations to within a factor of two. The results are discussed in terms of the interference between nuclear- and Coulomb-breakup amplitudes.

Photoneutron cross sections were measured for ${}^{94}$Mo, ${}^{95}$Mo, ${}^{96}$Mo, ${}^{97}$Mo, ${}^{98}$Mo, and ${}^{100}$Mo near the neutron threshold with quasi-monochromatic laser-Compton scattering $\ensuremath{\gamma}$ rays. The photoneutron data were analyzed with the Skyrme Hartree-Fock-Bogoliubov (HFB) plus quasiparticle random phase approximation (QRPA) model and the axially symmetric-deformed Gogny HFB plus QRPA model of $E1$ $\ensuremath{\gamma}$-ray strength. Combining the $\ensuremath{\gamma}$-ray strength function constrained by the present photoneutron data with either the nuclear resonance fluorescence data or the updated Oslo data to supplement the data below the neutron threshold, a thorough analysis of the reverse $(n,\ensuremath{\gamma})$ cross sections is made whenever measurements are available. The Oslo data and the corresponding uncertainties are updated based on the latest results of the $s$-wave neutron spacing and the average radiative width determined in particular for ${}^{96}$Mo. Finally, radiative neutron capture cross sections for two radioactive nuclei, ${}^{93}$Mo and ${}^{99}$Mo, are deduced with the $\ensuremath{\gamma}$-ray strength function method.

Low-lying states in {sup 56}Fe, up to an excitation energy of about 4 MeV, have been investigated by means of inelastic proton and deuteron scattering experiments at {ital E}{sub {ital p}}=65 and 400 MeV and at {ital E}{sub {ital d}}=56 MeV, respectively. Measured cross sections and analyzing powers have been compared with coupled-channels calculations using collective form factors; calculations in both the Schr{umlt o}dinger and Dirac formalisms have been carried out for the proton data. For each probe, the matrix elements have been deduced for transitions from the ground state and from the 2{sub 1}{sup +} state to six quadrupole (2{sup +}) states to one octupole (3{sub 1}{sup {minus}}) and two hexadecapole (4{sub 1}{sup +} and 4{sub 2}{sup +}) states. The obtained matrix elements and the previous values from {gamma} decay or electron inelastic scattering have been used to evaluate the isospin character of the transitions. To discuss the quadrupole mixed-symmetry states in {sup 56}Fe, the deduced neutron ({ital M}{sub {ital n}}) and proton ({ital M}{sub {ital p}}) components of the matrix elements, or equivalently the isoscalar ({ital M}{sub {ital s}}) and isovector ({ital M}{sub {ital v}}) parts, have been compared with theoretical calculations based on the neutron-proton interacting bosonmore » model and on the shell model evaluated in a full {ital f}-{ital p} configuration space. {copyright} {ital 1996 The American Physical Society.}« less

A nuclear beam of extremely low intensity was realized by accelerating decay particles from heavy radioactive nuclei through an AVF cyclotron. Alpha particles from a 241Am source (3.3 × 106 Bq) were accelerated up to 30 MeV with a cyclotron starting from a proper radius. The weak beam of alpha particles was detected and its energy and microscopic time structure was analyzed. The count rate was attenuated down to 5 counts per minute which is only 1 20 of the value estimated from source geometry and accelerator acceptance.

Elastic scattering of 3 He particles from 12 C, 28 Si, 58 Ni, 90 Zr and 208 Pb was measured at an incident energy of 450 MeV. Data were analyzed in the framework of the optical model based upon the Woods-Saxon parametrization. The depth of the real potential was determined to be about 30 MeV, irrespective of the target nucleus. It was found that volume integrals per nucleon of the real potentials became close to that of the proton and those of the imaginary potentials were about one half of that of the proton. A new empirical formula is proposed regarding the volume integrals per nucleon of the imaginary potentials.

Using quasimonochromatic laser-Compton scattering γ rays, total photoneutron cross sections were measured for 206 ,207 ,208Pb near neutron threshold with a high-efficiency 4π neutron detector. Partial E1 and M1 photoneutron cross sections along with total cross sections were determined for 207 ,208Pb at four energies near threshold by measuring anisotropies in photoneutron emission with linearly polarized γ rays. The E1 strength dominates over the M1 strength in the neutron channel where E1 photoneutron cross sections show extra strength of the pygmy dipole resonance in 207 ,208Pb near the neutron threshold corresponding to 0.32%-0.42% of the Thomas-Reiche-Kuhn sum rule. Several μN2 units of B(M1)→ strength were observed in 207 ,208Pb just above neutron threshold, which correspond to an M1 cross section less than 10% of the total photoneutron cross section. © 2012 American Physical Society., SCOPUS: ar.j, info:eu-repo/semantics/published

A high-resolution measurement of inelastic proton scattering off $^{90}\mathrm{Zr}$ near 0\ifmmode^\circ\else\textdegree\fi{} was performed at 295 MeV with a focus on a pronounced strength previously reported in the low-energy tail of giant dipole resonance. A forest of fine structure was observed in the excitation energy region 7--12 MeV. A multipole decomposition analysis of the angular distribution for the forest was carried out using the ECIS95 distorted-wave Born approximation code with the Hartree-Fock plus random-phase approximation model of $E1$ and $M1$ transition densities and inclusion of $E1$ Coulomb excitation. The analysis separated pygmy dipole and $M1$ resonances in the forest at ${E}_{\mathrm{PDR}}=9.15\ifmmode\pm\else\textpm\fi{}0.18\text{ }\text{ }\mathrm{MeV}$ with ${\ensuremath{\Gamma}}_{\mathrm{PDR}}=2.91\ifmmode\pm\else\textpm\fi{}0.64\text{ }\text{ }\mathrm{MeV}$ and at ${E}_{M1}=9.53\ifmmode\pm\else\textpm\fi{}0.06\text{ }\text{ }\mathrm{MeV}$ with ${\ensuremath{\Gamma}}_{M1}=2.70\ifmmode\pm\else\textpm\fi{}0.17\text{ }\text{ }\mathrm{MeV}$ in the Lorentzian function, respectively. The $B(E1)\ensuremath{\uparrow}$ value for pygmy dipole resonance over 7--11 MeV is $0.75\ifmmode\pm\else\textpm\fi{}0.08\text{ }\text{ }{e}^{2}\text{ }{\mathrm{fm}}^{2}$, which corresponds to $2.1\ifmmode\pm\else\textpm\fi{}0.2%$ of the Thomas-Reiche-Kuhn sum rule.

Photoneutron cross sections were measured for ${}^{118}$Sn, ${}^{119}$Sn, ${}^{120}$Sn, ${}^{122}$Sn, and ${}^{124}$Sn near neutron threshold with quasi-monochromatic laser-Compton scattering $\ensuremath{\gamma}$ rays. A systematic analysis of the present photoneutron data and existing neutron-capture data is made using the $\ensuremath{\gamma}$-ray strength function on the basis of the HFB + QRPA model of $E1$ strength supplemented with a pygmy dipole resonance, which was deduced from a previous study on ${}^{116}$Sn and ${}^{117}$Sn. Radiative neutron capture cross sections for two radioactive nuclei, ${}^{121}$Sn and ${}^{123}$Sn, are deduced through the $\ensuremath{\gamma}$-ray strength function method.

The γ-ray strength function method is devised to indirectly determine radiative neutron capture cross sections for radioactive nuclei. This method is applied here to the Pd107 (T1/2=6.5×106 yr) case. Photoneutron cross sections were measured for Pd105,106,108 near neutron threshold with quasimonochromatic laser-Compton-scattering γ-ray beams. These photoneutron cross sections as well as the reverse radiative neutron capture cross sections for Pd104,105 are used to provide constraints on the Pd107(n,γ)Pd108 cross section. © 2010 The American Physical Society.

Differential cross sections for the ${0}_{2}^{+}$ state at ${E}_{x}=7.654$ MeV in $^{12}\mathrm{C}$ were measured with the ($p,{p}^{\ensuremath{'}}$) reaction at an incident energy of $E$${}_{p}=300$ MeV, and in an angular range from ${\ensuremath{\theta}}_{\mathrm{Lab}}=2.7$${}^{\ifmmode^\circ\else\textdegree\fi{}}$ to ${40}^{\ifmmode^\circ\else\textdegree\fi{}}$. The cross-section data were compared with the distorted-wave Born-approximation calculations employing three types of transition densities obtained in a macroscopic collective model, a microscopic $\ensuremath{\alpha}$-cluster model, and a microscopic $\ensuremath{\alpha}$-cluster condensation model. It is concluded that the measured angular distribution of the differential cross sections for the $^{12}\mathrm{C}$($p,{p}^{\ensuremath{'}}$) reaction at 300 MeV is consistently described with the assumption that the ${0}_{2}^{+}$ state at ${E}_{x}=7.654$ MeV is the dilute $\ensuremath{\alpha}$-cluster condensed state.

Photoneutron cross sections were measured for $^{96}\mathrm{Zr}$ near neutron threshold with quasimonochromatic laser-Compton-scattering $\ensuremath{\gamma}$-ray beams. A systematic analysis of photoneutron and radiative neutron capture data for zirconium isotopes within the statistical model calculation leads to a unified picture of low-energy $\ensuremath{\gamma}$-ray strengths for zirconium isotopes that is described by the HFB $+$ QRPA model of $E1$ strength supplemented with an extra $\ensuremath{\gamma}$ strength attributed to a giant $M1$ resonance. Results of the systematic analysis including radiative neutron capture cross sections for radioactive $^{95}\mathrm{Zr}$ and $^{93}\mathrm{Zr}$ nuclei are presented.

We identify two electric isovector giant resonances at {ital E}{sub {ital x}}=28 and 33 MeV in {sup 12}C, and at {ital E}{sub {ital x}}=27 and 31 MeV in {sup 28}Si, distinguishing them from a continuum background in the ({sup 7}Li,{sup 7}Be) reaction at {ital E}{sub {ital L}}=26 MeV/nucleon and {theta}{sub {ital L}}=0{degree}. The shape of the underlying continuum is determined from a comparison of {Delta}{ital S}=0 and {Delta}{ital S}=1 energy spectra deduced with a {sup 7}Be-{gamma} coincidence method. The excitation energies of these resonances are consistent with those of the isovector giant quadrupole and monopole resonances previously observed by the electron scattering and the ({pi}{sup {plus minus}},{pi}{sup 0}) reaction, respectively, though the widths presently observed are much narrower.

Spin-flip (ΔS = 1) and non spin-flip (ΔS = 0) excitations were investigated in the (7Li,7Be) reactions on 12C and 28Si at EL = 26 MeV/A and θL = 0° by measuring separately the (7Li,7Beg.s.) and (7Li,7Be0.43MeV) reaction channels with the 7Be-γ coincidence technique. For both 12C and 28Si, the giant dipole resonance (GDR) is clearly identified in the ΔS = 0 spectrum, and its strength distribution is in good agreement with that observed by the photonuclear reaction. In 12C, the 1− and 2− components of the spin-dipole resonance (SDR) are also observed in the ΔS = 1 spectrum. Not only the magnitudes but also the shapes of the GDR and 1− SDR are found to be very similar in 12C. On the other hand, in 28Si, though a possible 2− component of the SDR is observed, the 1− SDR is not clearly identified as a resonance. Beyond the excitation energy of the GDR for both 12C and 28Si, ΔS = 0 cross sections are enhanced relative to ΔS = 1 ones, which suggests excitation of isovector giant resonances at 2ℏω. In addition, a possible isovector octupole resonance at 1ℏω was observed in the ΔS = 0 spectrum of 28Si.

A high-resolution ({alpha},{alpha}{prime}) experiment has been performed in order to confirm the existence of the low-energy octupole resonance (LEOR) in {sup 208}Pb. Until now there was a puzzling discrepancy; an ({alpha},{alpha}{prime}) experiment denied the existence, while a ({ital p},{ital p}{prime}) measurement affirmed it. The present ({alpha},{alpha}{prime}) reaction with an improved resolution of 27 keV has identified clustering {ital L}=3 levels in the LEOR region'' in agreement with the former ({ital p},{ital p}{prime}) measurement. The observed strength, however, is weaker than the ({ital p},{ital p}{prime}) results, suggesting the coexistence of the isovector strength.

Photoneutron cross sections were measured for $^{117}\mathrm{Sn}$ and $^{116}\mathrm{Sn}$ near the neutron thresholds at $6.94$ and $9.56$ MeV, respectively, with quasi-monochromatic laser-Compton scattering $\ensuremath{\gamma}$ rays. The $^{117}\mathrm{Sn}$ cross section, which is strongly enhanced near the low threshold, provides evidence for the presence of extra $\ensuremath{\gamma}$ strength in the low-energy tail of the giant dipole resonance. A coherent analysis of the photoneutron data for $^{117}\mathrm{Sn}$ together with the neutron capture on $^{116}\mathrm{Sn}$ shows that the $\ensuremath{\gamma}$-ray strength function is balanced in the photoneutron and neutron capture channels in terms of the microscopic Hartree-Fock-Bogoliubov plus quasiparticle random-phase approximation model of $E1$ strength combined with a pygmy $E1$ resonance at $8.5$ MeV. The high-energy part of the pygmy resonance is also suggested in the photoneutron cross section for $^{116}\mathrm{Sn}$.

Photoneutron cross sections were measured for $^{80}\mathrm{Se}$ immediately above the neutron separation energy with quasimonochromatic $\ensuremath{\gamma}$-ray beams to experimentally constrain the $E1$ $\ensuremath{\gamma}$ strength function for $^{80}\mathrm{Se}$. Two sets of the $\ensuremath{\gamma}$ strength function and the level density that equally meet the experimental constraint predict largely different neutron capture cross sections for $^{79}\mathrm{Se}$. Based on the Maxwellian-averaged cross sections of the latest compilation complemented with the predicted cross sections for $^{79}\mathrm{Se}$, we calculated $\ensuremath{\sigma}N$ values of the main $s$-process component using a phenomenological model and deduced empirical abundances of the weak $s$-process component. An attempt is made of considering the implications of the abundance ratios of $^{80}\mathrm{Kr}$ and $^{82}\mathrm{Kr}$ within the framework of phenomenological models for the weak $s$ process.

The relative strength ({Delta}{ital S}=1)/(({Delta}{ital S}=0)+({Delta}{ital S}=1)) of isovector spin excitations, {ital P}{sub sf}, in the high-lying resonance region of {sup 12}C was investigated with the ({sup 7}Li,{sup 7}Be) reaction at {ital E}{sub {ital L}}=26 MeV/nucleon and {theta}{sub {ital L}}=0{degree} by separately measuring the ({sup 7}Li,{sup 7}Be{sub g.s.}) and ({sup 7}Li,{sup 7}Be{sub 0.43} MeV) reaction channels with the {sup 7}Be-{gamma} coincidence technique. The relative strength {ital P}{sub sf} was derived up to an excitation energy of 18 MeV in {sup 12}B and found to have a constant value of 0.4--0.5 for the continuum irrespective of excitation energy and 0.5 for the isovector dipole resonance centered at {ital E}{sub {ital x}}=7.6 MeV.

The movement of K, Ca, Fe, Zn and Rb concentrations was investigated by the PIXE (particle induced X-ray emission) method for blood, liver and kidneys collected from rats administered Rb through an intraperitoneal injection. The Rb concentrations showed a prominent increase 7–8 days after the injection and a recovery to normal values a month after the injection for every sample studied, while the movement of other elements was less evident. There seemed to be no possible correlations between Rb and K concentrations, which is in contrast to the previous results suggesting a strong exchange effect between Rb and K concentrations for the autoptic human kidneys.