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We have developed a new positron annihilation measurement system via electron-positron pair creation using by laser Compton scattering (LCS) gamma beam direct implantation into bulk materials at NewSUBARU synchrotron radiation facility, LASTI, University of Hyogo, Japan. LCS gamma beam is easy to control energy, and its energy is quasi-monochromatic and high directivity. These parameters are determined by laser wavelength and electron kinetic energy. In this study, maximum energy 16.9 MeV LCS gamma beam generation by Nd:YVO4 laser (wavelength 1064 nm) and circling electron (982 MeV) directly irradiated into samples for Doppler broadening measurement in an atmosphere. The gamma beam created high energetic positrons to MeV order. This measurement could be a simple setup consisting of a single HP-Ge detector, amplifier, and multi-channel analyzer. As a demonstration, we have tried to measure the Doppler broadening spectra of pure iron, electron irradiated iron and silicon by this system.We have developed a new positron annihilation measurement system via electron-positron pair creation using by laser Compton scattering (LCS) gamma beam direct implantation into bulk materials at NewSUBARU synchrotron radiation facility, LASTI, University of Hyogo, Japan. LCS gamma beam is easy to control energy, and its energy is quasi-monochromatic and high directivity. These parameters are determined by laser wavelength and electron kinetic energy. In this study, maximum energy 16.9 MeV LCS gamma beam generation by Nd:YVO4 laser (wavelength 1064 nm) and circling electron (982 MeV) directly irradiated into samples for Doppler broadening measurement in an atmosphere. The gamma beam created high energetic positrons to MeV order. This measurement could be a simple setup consisting of a single HP-Ge detector, amplifier, and multi-channel analyzer. As a demonstration, we have tried to measure the Doppler broadening spectra of pure iron, electron irradiated iron and silicon by this system.

We have revealed several unique characteristics of germ cell development using rainbow trout, including the fact that spermatogonia transplanted into the peritoneal cavity of newly hatched embryos migrate toward recipient gonads, that spermatogonia transplanted into female recipients start oogenesis and produce functional eggs and that diploid germ cells transplanted into triploid trout can complete gametogenesis. By combining these unique features of fish germ cells, we established allogeneic and xenogeneic transplantation systems for spermatogonia in several fish species. Spermatogonia isolated from the mature testes of vasa-green fluorescent protein (Gfp) transgenic rainbow trout were transplanted into the peritoneal cavity of triploid masu salmon newly hatched embryos. These spermatogonia migrated toward recipient salmon genital ridges with extending pseudopodia and were subsequently incorporated into them. We further confirmed that the donor-derived spermatogonia resumed gametogenesis and produced sperm and eggs in male and female salmon recipients, respectively. By inseminating the resulting eggs and sperm, we obtained only rainbow trout offspring in the F1 generation, suggesting that the triploid salmon recipients produced functional gametes derived only from donor trout. We further confirmed that this intra-peritoneal transplantation of germ cells is applicable to several marine fishes, which could be of benefit in the production of bluefin tuna that has a large broodstock (>100 kg) and is difficult to maintain in captivity. Gamete production of bluefin tuna could be more easily achieved by generating a surrogate species, such as mackerel, that can produce tuna gametes.

In atomic collisions in solids by the ions with very strong electronic interaction, it is confirmed that the atomic displacement process is enhanced by electronic excitation. Two experimental results are introduced as examples. The first is the columnar defect formation in a cuprate superconductor Bi2Sr2CaCu2Ox which is irradiated with 3.5 GeV Xe ions, the second is sputtering induced by highly charged ion (HCI) bombardment (Xeq+; q = 15 –44). Since there are some indications to show that these phenomena might be the outcome of the Coulomb explosion process, we tried to make a molecular dynamics simulation of the sputtering process based on this Coulomb explosion mechanism. Good agreement between the simulation and experiment was found. For sputtering of electrically conductive materials, the importance of neutralization dynamics of the HCI and the highly charged region in the solid materials was indicated.

An accurate exclusive measurement of the 8 Li( α , n) 11 B reaction cross sections has been carried out successfully by using a highly efficient detector system and high-purity low energy 8 Li-beam. The excitation function obtained with high statistics in the energy region from 0.9 to 2.7 MeV in the center-of-mass system is reported. The present cross sections show that the averaged ratio of total cross section to the inverted neutron capture cross section is 4 ∼ 5. Some details of the experimental method are also described.

We study the effects of neutrino interactions before, during, and after the operation of the r-process in the context of a relativistic hydrodynamic neutrino-energized wind model that includes a Boltzmann solver for the dominant neutrino transport. We also employ newly available charged- and neutral-current interaction rates. Studies are made in a model with a short dynamical timescale that gives a fair reproduction of the solar system r-process abundance curve and hence could be a fair approximation to the true supernova environment. We confirm that charged- and neutral-current interactions can have specific unique effects on the final abundances. Early on, charged-current interactions determine the electron fraction, while later on, neutrino-induced neutron emission can continue to provide a slight neutron exposure even after the freezeout of the r-process. We propose two new potentially observable effects that derive from the use of a more realistic hydrodynamic model and/or new neutrino interaction rates. One is an enhanced odd-even effect in the final abundances, and the other is an enhancement of light A = 68-76 nuclei in the final abundances. These effects are consistent with some recent observations of r-process abundances in metal-poor halo stars and might help to identify the neutrino fluxes present near the freezeout of the r-process.

Neutron-capture elements have been detected in several metal-deficient halo stars with metallicity of [Fe/H] ∼ −1.5 − −3.0. These detections have indicated that the observed abundance pattern of heavy neutron-capture elements is very similar to that of the solar r-process elements for the mass region 56

We study the effects of the outer boundary conditions in neutrino-driven winds on r-process nucleosynthesis. We perform numerical simulations of hydrodynamics of neutrino-driven winds and nuclear reaction network calculations. As an outer boundary condition of hydrodynamic calculations, we set a pressure upon the outermost layer of the wind, which is approaching toward the shock wall. Varying the boundary pressure, we obtain various asymptotic thermal temperatures of expanding material in the neutrino-driven winds for resulting nucleosynthesis. We find that a slightly lower asymptotic temperature reduces the charged particle reaction rates and the resulting amount of seed elements and leads to a high neutron-to-seed ratio for a successful r-process abundance pattern, which is in reasonable agreement with the solar system r-process abundance pattern. As a result, the asymptotic temperature, slightly lower than those in previous studies of neutrino-driven winds, can lead to a successful r-process even for the typical proto-neutron star mass MNS ~ 1.4 M☉. We also explore the relation between the boundary condition and the neutron star mass, which is related to the progenitor mass, for a successful r-process.

Hypergravity (2G) exposure elevated the nociceptive threshold (pain suppression) concomitantly with evoked neuronal activity in the hypothalamus. Young Wistar male rats were exposed to 2G by centrifugal rotation for 10 min. Before and after 2G exposure, the nociceptive threshold was measured as the withdrawal reflex by using the von Frey type needle at a total of 8 sites of each rat (nose, four quarters, upper and lower back, tail), and then rats were sacrificed. Fos expression was examined immunohistochemically in the hypothalamic slices of the 2G-treated rats. When rats were exposed to 2G hypergravity, the nociceptive threshold was significantly elevated to approximately 150 to 250% of the 1G baseline control levels in all the examination sites. The 2G hypergravity remarkably induced Fos expression in the paraventricular and arcuate nuclei of the hypothalamus. The analgesic effects of 2G hypergravity were attenuated by naloxone pretreatment. Data indicate that hypergravity induces analgesic effects in rats, mediated through hypothalamic neuronal activity in the endogenous opioid system and hypothalamo-pituitary-adrenal axis.

Acicular manganese zinc ferrite fine particles were made from the as raw materials of acicular α-FeOOH, Mn(C5H7O2)3, and Zn(C5H7O2)2. These fine particles were oriented with the long axis in parallel to the magnetic flux direction by a magnetic field of 7 kOe. The fine particles were then formed into thin, multi-layered toroidal cores. The green bodies were sintered at 1200°C for 6 hours in air, then cooled in a nitrogen atmosphere. The crystals of sintered manganese zinc ferrites were strongly oriented to the direction of the (110) plane of the spinel; this plane was formed along the upper plane of toroidal cores. The crystal growth behavior was similar to that of a manganese zinc ferrite single crystal of the (110) plane. The initial permeability of crystal-oriented manganese zinc ferrites was 2120. The sample exhibited good high-frequency magnetic properties.

The radiation damage and the radiation-induced segregation (RIS) in type 304 austenitic stainless steel single crystal were investigated with 1.6 MeV He ion irradiation up to 2.5 × 1017 cm−2 at RT by using RBS and PIXE with channeling conditions (RBS-C and PIXE-C). By the RBS-C experiments, it is found that radiation-induced damage for (1 1 0) orientation increased more slowly than those for (1 0 0) and (1 1 1) orientations with He ion dose. By the PIXE-C experiments, it is found that the Si atoms are displaced from the lattice sites and segregate significantly to the surfaces of (1 0 0), (1 1 0) and (1 1 1) orientations and the S atoms also seem to be enriched slightly in the (1 0 0) and (1 1 0) surfaces during He ion irradiation.

High resolution PIXE facilities (X-ray crystal spectrometers working on ion beams of accelerators) and their applications in chemical analysis and in basic research are surveyed.

Performance of a micro WDX-PIXE system that consists of position sensitive x-ray spectrometer and the heavy ion microbeam line is described. The influence of the position resolution of the position sensitive proportional counter (PSPC) used in the spectrometer on system energy resolution is discussed based on the measured values for C and O K x-rays. The system has successfully been used for chemical state analysis of various compound materials and small area of the materials (< 3 × 10-3 mm 2) can be analyzed.

Helium bubble structure was examined on a helium-implanted stainless steel after applying two kinds of heat input. Helium ions were implanted on Type 304 stainless steel at 573 K from 2 to 200 appm to a peak depth of 0.5 μm from the surface. After that, weld thermal history was applied by an electron beam. The cooling rates were selected to be 370 and 680 K/s from 1023 to 773 K. TEM observation revealed that nucleation and growth of helium bubbles were strongly dependent on the cooling rate after welding and the helium concentration.

Implantation with nitrogen ions (N 2 + ) accelerated at 150 keV has been performed in high purity aluminum (5 N). The formation of AIN with various dose of I X 10 21 to I × 10 22 ions m -2 was investigated using several methods such as a grazing incidence X-ray diffraction analysis (XRD). Auger electron spectroscopy ( AES ) and transmission electron microscopy. Furthermore, the dynamic ultra-microhardness of the modified surface was evaluated by measuring the penetration depth with an applied load. The forming of AIN in aluminum was identified by the grazing incident XRD. The AES depth profile of nitrogen concentration corresponded to the profile calculated by a theoretical computer simulation. The morphology of formed AIN was not a thin film but dispersive particles. The microhardness increased due to the formation of AIN. The depth of the hardened region was about 100 nm from the aluminum surface.

Objective and Design: Effects of Y-24180 on antigen-induced asthmatic responses were evaluated in actively sensitized guinea pigs and the effects were compared with those of several anti-asthmatic drugs.¶Materials: Male Hartley guinea pigs were used.¶Treatment: Guinea pigs were actively sensitized with ovalbumin and were pretreated with pyrilamine. Y-24180 was orally administered to the animals 3 h and others were 1 h before the antigen challenge.¶Methods: The airway hyperresponsiveness was measured according to the method of Konzett and Rossler with some modifications. The immediate asthmatic response (IAR) and late asthmatic response (LAR) were measured by the oscillation method. Inflammatory cells infiltrated into the lungs were counted after the bronchoalveolar lavage.¶Results: Under oral administration before or after the challenge with antigen, Y-24180, OKY-046, and ONO-1078 suppressed the antigen-induced airway hyperresonsiveness. Moreover, Y-24180, ONO-1078, AA-2414, and theophylline suppressed both the IAR and LAR, but OKY-046 only suppressed the LAR. Among the test drugs, only Y-24180 and theophylline suppressed the antigen-induced accumulation of eosinophils in the bronchoalveolar lavage fluid.¶Conclusions: The data indicate practical participation of PAF in the development of antigen-induced asthmatic responses in animals, and usefulness of Y-24180 in the clinical treatment of asthma as well as other anti-asthmatic drugs.

We studied the effects of (+/-)-4-(2-chlorophenyl)-2-[2-(4-isobutylphenyl)ethyl]-6,9-dimethy l-6H-thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4]diazepine (Y-24180), a long-acting antagonist for platelet-activating factor (PAF), on antigen-induced eosinophil infiltration and interleukin-5 (IL-5) release in the bronchoalveolar lavage fluid (BALF) of mice. Mice actively sensitized with ovalbumin (OA) were challenged by injecting intratracheally OA 3 times every fourth day. Both the number of eosinophils and level of IL-5 were significantly increased in the BALF 24 hr after the last OA challenge. Either Y-24180 or prednisolone was orally administered once a day for 10 days beginning one day before the first OA challenge. WEB2086, another PAF antagonist, was orally administered once or twice a day for 10 days. Y-24180 (0.3 - 3 mg/kg) suppressed the eosinophil infiltration in a dose-dependent manner and suppressed the IL-5 release at the highest dosage. Prednisolone (10 mg/kg) significantly suppressed both the eosinophil infiltration and IL-5 release. In contrast, WEB2086 affected neither the eosinophil infiltration nor IL-5 release when administered once a day (10 - 100 mg/kg/day). This drug never affected the IL-5 release but significantly suppressed eosinophil infiltration even when administered twice a day (30 - 200 mg/kg/day). These results indicate that the suppressive effect of Y-24180 on allergic pulmonary eosinophilia is due to not only to its long-lasting PAF-antagonism but also due to its suppressive effect on IL-5 release.

High purity iron sheets were implanted with high-dose nitrogen ions accelerated to 150 keV. The implanted surfaces were examined by thin-film X-ray diffraction method and high resolution transmission electron microscopy (HRTEM). The implanted surfaces contain the metastable Fe 16 N 2 phase in addition to ϵ-nitride. HRTEM reveals that Fe 16 N 2 domains have lattice fringes of double spacing along the [121] direction of the matrix and spherical morphologies with coherent interfaces.

Summary A series of 4-(2-chlorophenyl)-9-methyl-6 H -thieno[3,2- f ][1,2,4]triazolo[4,3- a ][1,4]diazepine derivatives bearing substituents at the 2- and 6-positions were synthesized, and evaluated in vitro for their inhibitory activity on rabbit platelet aggregation induced by platelet activating factor (PAF) and in vivo for their preventing effect on PAF-induced mortality in mice. The length of alkyl or arylalkyl side chain at the 2-position was responsible for enhancing the affinity for the PAF receptor. The simultaneous substitution at both the 2- and 6-positions resulted in a successful separation of the affinity for the PAF receptor from that for the benzodiazepine (BZ) receptor. Thus, (±)-4-(2-chlorophenyl)-2-[2-(4-isobutylphenyl)ethyl]-6,9-dimethyl-6 H -thieno[3,2- f ][1,2,4] triazolo[4,3- a ][1,4]diazepine (Y-24180) was confirmed to be a specific antagonist for the PAF receptor and is currently under clinical trials.

A project to acquire directly nuclear cross sections of (α, n) and (p, n) reactions using low energy light neutron-rich radioactive nuclear beams (RNB) is in progress at JAERI-Tandem facility. The method of the production of neutron-rich RNB, an improvement of a gas counter (MSTPC) in order to work effectively under the high RNB-injection rate, and the feasibility of our experiments are discussed.

We study the effects of the outer boundary conditions in neutrino-driven winds on the r-process nucleosynthesis. Varying the boundary condition, we obtain various asymptotic thermal temperature of expanding material. As a result, we find that the slightly lower asymptotic temperature than those in the previous studies of the neutrino-driven winds can lead to a successful r-process even for the typical proto-neutron star mass MNS 1.4M⊙. We also discuss the relation between the boundary condition and neutron star mass, which is related to the progenitor mass, for the successful r-process

Recently, detections of the r-process elements have been done for several metal-deficient halo stars with metallicity of [ Fe H ] ∼ −1.5 −−3.0. They have indicated that the observed abundance pattern of heavy elements is very similar to that of the solar r-process elements for the mass region 56

In order to study the starting point of the r-process, the 16 N(α, n) cross section has been measured directly at the energy region of E cm = 1.5 – 4.0 MeV, corresponding to the Gamow peak energy T 9 = 2 – 6.

We have revealed several unique characteristics of germ cell development using rainbow trout, including the fact that spermatogonia transplanted into the peritoneal cavity of newly hatched embryos migrate toward recipient gonads, that spermatogonia transplanted into female recipients start oogenesis and produce functional eggs and that diploid germ cells transplanted into triploid trout can complete gametogenesis. By combining these unique features of fish germ cells, we established allogeneic and xenogeneic transplantation systems for spermatogonia in several fish species. Spermatogonia isolated from the mature testes of vasa-green fluorescent protein (Gfp) transgenic rainbow trout were transplanted into the peritoneal cavity of triploid masu salmon newly hatched embryos. These spermatogonia migrated toward recipient salmon genital ridges with extending pseudopodia and were subsequently incorporated into them. We further confirmed that the donor-derived spermatogonia resumed gametogenesis and produced sperm and eggs in male and female salmon recipients, respectively. By inseminating the resulting eggs and sperm, we obtained only rainbow trout offspring in the F1 generation, suggesting that the triploid salmon recipients produced functional gametes derived only from donor trout. We further confirmed that this intra-peritoneal transplantation of germ cells is applicable to several marine fishes, which could be of benefit in the production of bluefin tuna that has a large broodstock (100 kg) and is difficult to maintain in captivity. Gamete production of bluefin tuna could be more easily achieved by generating a surrogate species, such as mackerel, that can produce tuna gametes.

The characterization of the single crystal of type 304 stainless steels was performed by using particle induced x-ray emission and Rutherford backscattering spectroscopy with channeling technique (PIXE-C and RBS-C). They proved that the solution annealing process is absolutely necessary for production of a good single crystal of stainless steels. They are also shown that the positions of P atoms before He irradiation were mostly substitutional sites of fcc structure and that MeV He ion irradiation induced segregation of Si and S atoms to the (110) surface.

Nickel single crystal specimens were bombarded with various heavy ions, 0.2 MeV He+, 2.0 MeV C+, 3.5 MeV Si2+, 4.0 MeV Ni2+ ions, up to the same amounts of displacement per atom (dpa), and residual rate of defects in heavy-ion induced cascades was investigated by Rutherford backscattering (RBS) spectroscopy using channeling technique. Displacement damages are found to be variable with primary knock-on atom (PKA) energies, revealing a cascade quenching due to the recombination of point defects produced primarily. Residual rate of defects obtained experimentally are qualitatively in agreement with existing theoretical calculations.

Variable-energy (0–30 keV) positrons were used to study the depth distribution of heavy-ion induced vacancy type defects in the following specimens, SUS304 and SUS316 austenitic stainless steels, a SUS444 ferritic stainless steel and nickel metal, which were irradiated by 0.5 MeV He+, 2.0 MeV C+, 3.5 MeV Si2+ and 4.0 MeV Ni2+ ions up to 0.01 dpa at peak. Vacancy type effective residual defects (ERD) were evaluated from the line shape parameterS of Doppler broadened positron annihilation photon spectra. With increasing primary knockon atom (PKA) energy, a decrease of the vacancy type ERD was observed. The ERD differences among the specimens are discussed in comparison with theoretical predictions.

A novel and potent antagonist of platelet-activating factor (PAF), Y-24180 (4-(2-chlorophenyl)-2-[2-(4-isobutylphenyl)ethyl]-6,9-dimethyl-6H- thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4] diazepine) was investigated for the effects on the skin reactions induced by chemical mediators and the Arthus reactions. In the rat dorsal skin, Y-24180 (0.1-10 mg/kg, p.o.) inhibited increase in vascular permeability by the intradermal PAF injection in a dose dependent manner and the inhibitory activity was 60 times more potent than that of WEB 2086. While even at doses as large as 10 mg/kg, p.o., it had no effect on vascular permeability in the rat skin induced by histamine, serotonin, bradykinin and leukotriene D4. On a reversed passive Arthus reaction in rat dorsal skin, Y-24180 (0.1-1 mg/kg, p.o.) markedly inhibited vascular permeability in a dose dependent manner and the inhibitory activity was 15 times more potent than that of WEB 2086. Y-24180 also inhibited the Arthus dermal reaction in rabbits (0.03-0.3 mg/kg, p.o.) and guinea pigs (0.1-1 mg/kg, p.o.). In addition, Y-24180 (0.1-10 mg/kg, p.o.) significantly reduced the exudate volume and the number of infiltrated inflammatory cells in the reversed passive Arthus pleural reaction in rats. Furthermore, in rat passive Arthus pancreatitis, Y-24180 (0.3-10 mg/kg, p.o.) significantly inhibited the dye extravasation from the pancreas. These results provide strong evidence that endogenous PAF plays an important role as a mediator in the type III allergic inflammation.

The characteristics of stored ions in a Kingdon trap have been investigated. The charge distribution of stored ions was measured by a time of flight (TOF) mass spectrometer. Storage of Arq+ (q = 1, 2, 3, 4) produced by electron beam irradiation has been confirmed. The dependences of Ar ion yields on the trapping potential and storage time have been systematically studied. Applying a voltage to end plates is very important for the storage of ions. Remarkable oscillations of the ion yields are found in the decay curves as a function of storage time for Ar+, Ar2+ and Ar3+ indicating periodical motion of each ion group about the central wire. The three dimensional orbits of ions in the trap are analysed by a computer calculation to understand the experimental results.

K, L, and M X-rays in the wavelengths between 6Å and 130Å generated by the bombardment of 200 keV protons and other heavy ions were measured by means of a wavelength dispersive Bragg’s spectrometer. The X-ray peak intensity was fairly high in general, while the background was very low. The technique was favorably applied to a practical analysis of several light elements (Be, B, C, N, O, and F). Use of moderate-energy heavy ions considering the wavelength selectivity in X-ray generation was effective for the element analysis. The high-resolution spectrometry in the analytical application of ion-induced X-ray generation was found to be useful for the study of fine electronic structure, e.g. satellite and hypersatellite X-ray study, and of the chemical state of materials.

Analyses were conducted of various models and mechanisms of highly charged ion (HCI) and swift-heavy ion energy transfer into a solid target, such as hollow atom formation, charge screening, neutralization, shock wave generation, crater formation, and sputtering. A plasma model of space charge neutralization based on impact ionization of semiconductors at high electric fields was developed and applied to analyze HCI impacts on Si and W. Surface erosions of semiconductor and metal surfaces caused by HCI bombardments were studied by using a molecular dynamics simulation method, and the results were compared with experimental sputtering data.

The inhibitory effect of Y-24180, 4-(2-chlorophenyl)-2-[2-(4-isobutylphenyl)ethyl]-6,9-dimethyl-6H-t hieno [3,2-f][1,2,4]triazolo [4,3-a][1,4]diazepine, on platelet activating factor (PAF)-induced platelet aggregation and the specific binding of 3H-PAF to platelets was compared with other thienodiazepine derivatives, WEB 2086 and etizolam. Y-24180 inhibited PAF-induced rabbit platelet aggregation in vitro (IC50 3.84 nM), but had little effect on adenosine diphosphate- or arachidonic acid-induced aggregation. WEB 2086 and etizolam also showed an inhibitory effect of PAF-induced aggregation (IC50 values are 456 and 6730 nM, respectively). In PAF-induced human platelet aggregation, Y-24180 (IC50 0.84 nM) was more potent than WEB 2086 (IC50 4.21 nM) and etizolam (IC50 998 nM). Y-24180, WEB 2086 and etizolam displaced 3H-PAF binding from the washed-platelets of rabbits with an IC50 value of 3.50, 9.35 and 29.5 nM, respectively. In rabbits, pretreatment with Y-24180 and WEB 2086 antagonized PAF-induced platelet aggregation dose-dependently. The significant inhibitory effect of Y-24180 (1 mg/kg, p.o.) lasted 72 hr after a single dose oral administration. WEB 2086 (10 mg/kg, p.o.) also antagonized the ex vivo response induced by PAF 1 hr after administration, but no significant effect was observed 3 hr after administration. Y-24180 displaced 3H-diazepam binding from the synaptosomal membranes of rat cerebral cortex with a Ki value of 3.68 microM. The affinity of Y-24180 for benzodiazepine(BZP) receptors was lower than those of WEB 2086 and etizolam and was about 1000 times lower than that for PAF receptors in platelets.

The aims of the New SUBARU project are to promote industrial applications in the VUV and soft X-ray region and to develop research and development towards new light sources. The main facility of the New SUBARU project is the 1.5 GeV electron storage ring which is under construction at the SPring-8 site in Harima Science Garden City, Japan. The storage ring is quasi-isochronous and has variable momentum dispersion for the deep study of beam dynamics in very short bunches.

The effects of columnar defects produced by swift heavy-ion irradiation on magnetic flux pinning were studied for the polycrystalline La1.85Sr0.15CuO4. The bulk specimens were irradiated with 3.5 GeV 136Xe31+ ions from a single direction or multi-directions in order to investigate the effects of columnar defect configuration. The magnetization hysteresis was measured with a super-conducting quantum interference device (SQUID) magnetometer, and the critical current density Jc and irreversibility line were observed. In the specimens irradiated from multi-directions, more enhancement of the critical current density and larger shifts of the irreversibility line to higher fields were observed than in the specimens irradiated from a single direction.

The behavior of a vortex system in the presence of columnar defects in a La1.85Sr0.15CuO4 single crystal irradiated with swift heavy ions (3.5 GeV 136Xe31+) is studied by measuring magnetization and AC susceptibility. The absolute value of the magnetization of the irradiated sample is significantly enhanced compared to the unirradiated one. The irreversibility line is shifted to higher temperatures as the defect density increases. It is found that for B > Bcr similar 0.5 T, " of irradiated samples exhibits double peaks, suggesting that the liquid-glass transition proceeds via two steps.

Carbon thin film was bombarded with high charge state Xeq+ ions, and the secondary carbon yields were measured as a function of charge state in the broad range of q = 8 to 44 at the kinetic energy of 1.0 MeV and, also, q = 44 at 175 keV. It is found that the secondary ion yields per incident ion increase with increasing q; the increase rate is remarkably high in q > 26 with the rate of q8.5 and rather moderate in q > 31. The yield and spectra of the secondary ions are not very different for 1.0 MeV and 175 keV for Xeq+ (q = 44) ion incidence.

A systematic study of astrophysical reaction rates of (α, n) and (p, n) reactions on light neutron‐rich nuclei by using low‐energy radioactive nuclear beam is in progress at the tandem facility of Japan Atomic Energy Research Institute. Exclusive measurements of 8Li(α, n)11B and 16N(α, n)19F reaction cross sections have been performed successfully. Their excitation functions together with the experimental method are presented.

A new titanium alloy for medical implants was implanted with nitrogen ions to improve corrosion resistance in physiological saline solution. The nitrogen ion implanted titanium showed marked changes in the corrosion resistance with various doses. Ti/sub 2/N was formed at lower dose and TiN was formed with increasing nitrogen dose. Corrosion potential shifted toward the noble direction and the passivation current density decreased by one order of magnitude with a dose of 2/spl times/10/sup 21/ N/sub 2//sup +//m/sup 2/. No significant improvement was obtained with higher dose. Titanium alloy was implanted with nitrogen ions at multi-energy to obtain a homogeneous nitrogen concentration profile in the implanted layer. Corrosion resistance was improved by the multi-energy implantation.