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A method that predicts gene expression levels from cell morphology was developed. Prediction within a reprogramming batch was sufficiently robust to provide a practical approach for estimating expression levels of genes and monitoring the purification process.

An accelerator based on the Cyclotron Auto-Resonance Acceleration is expected to be implemented in the application which need high-current beams, such as a radioisotope production and a neutron source. The electron accelerator with this kind of acceleration technique using a wave guide for a TE11 traveling wave located in a solenoid was proposed and developed in the previous study by Prof. J. L. Hirshfield at Yale University. For application of this kind of acceleration to the acceleration of proton, we have demonstrated the acceleration of protons with computer simulations of a TE111 standing wave cavity, a superconducting coil system and the beam dynamics. For demonstration of the Cyclotron Auto Resonance Acceleration with a TE111 mode standing wave, we have been designing a model cavity for rotating TE111 mode standing wave. It is a key technology for the realization of the cyclotron auto-resonance accelerator for the protons. The cavity is designed for the cyclotron resonance of muons in the field of 3.5 T with the RF frequency of 500 MHz which significantly reduces the size of the cavity from the one for the proton cyclotron resonance. We have tested couplings for input and probing the RF and tuning method. We report the current status of the design of the RF cavity.

In general, a cyclotron has relatively higher energy efficiency than other types of accelerator due to compactness and simplification of magnets and RF systems. The maximum energy efficiency of 13 % was achieved at PSI-HIPA. The power losses in electromagnets and RF systems account for 70 % of the total power consumption. The energy efficiency of a cyclotron will be improved by introducing power saving measures such as superconducting equipment and electric power free devices. We started designing of a new cyclotron consisting of main electromagnets using SmCo permanent magnets (PM) and superconducting RF (SRF) cavities coated with MgB2 to achieve energy efficiency of 30 % or more. Key technologies required for realization of an SRF system in a cyclotron are manufacturing of an MgB2 superconducting cavities and its cryomodules. Especially the leakage field of the main magnets around the superconducting cavities should be tolerable by reducing the field under the thermodynamic critical field. In this paper, we have identified the R&D issues for each element as the first step in the development of our high energy-efficiency SRF-PM cyclotron.

The target vessel, which enclosing liquid mercury, for the pulsed spallation neutron source at the J-PARC is severely damaged by cavitation caused by proton beam-induce pressure waves in mercury. To mitigate the cavitation damage, we adopted a double-walled structure with a narrow channel for the mercury at the beam window of the target vessel. The narrow channel disturbs the growth of cavitation bubbles due to the pressure gradient. In addition, gas microbubbles are injected into the mercury to suppress the pressure waves. After finishing service operation, the front end of the target vessel was cut out to inspect the effect of those cavitation damage mitigation technologies on the interior surface. The damage depth of the cutout specimens for the original design type and double-walled target vessels were quantitatively investigated by the replica method. The results showed that the double-walled target facing mercury with gas microbubbles operate 1812 MWh for an average power of 434 kW is equivalent to the damage of original design target operated 1048 MWh for average power of 181 kW. The erosion depth due to cavitation in the narrow channel is clearly smaller than on the wall facing bubbly mercury.

A mercury target vessel for the spallation neutron source at the J-PARC, which the mercury vessel was covered with the water shroud, was improved to realize the operation at the high beam power in two steps. In the first step to realize the stable operation at 500 kW, the basic structure of the initial design was followed and the connection method between the mercury vessel and the water shroud was changed to prevent the failure from the connection. The service operation at the beam power of 500 kW was realized in the about eight months. In the second step to realize the stable operation at 1 MW, the new structure which only rear ends of vessels were connected was investigated. The new structure which has the cooling of the mercury vessel to reduce thermal stress and the thick internal and external vessels of the water shroud to increase the stiffness for the internal pressure was adopted. The stresses in each vessel were lower than the allowable stress based on the elastic design criteria and it was confirmed that the operation with a beam power of 1 MW could be conducted.

The NIRS-930 cyclotron supplies several ion beams for basic science and applied research in the fields of nuclear medicine, biology, and physics at the National Institutes for Quantum and Radiological Science and Technology (QST). The main ion species used are protons and helium for these experiments. In addition, heavy ions such as carbon and neon are also supplied. These ions are produced by the compact ECR ion source with all permanent magnets (Kei-source). The Kei-source is installed on top of the NIRS-930, and the ions extract from the ion source pass through the low-energy beamline and enter the NIRS-930. In the future, the ion source will be required to produce highly charged ions of various ion species and increase the beam intensity. The Kei-source has not been optimized for the position of the extraction electrode because a sufficient beam current was obtained. In the case of He2+, the transmission efficiency from faraday cup 2 (FC2) and faraday cup 3 (FC3) was about 60%. In this study, the position of the extraction electrode was optimized and the beam transmission efficiency of the low-energy beam transport will be improved by remotely controlling the extraction electrode of Kei-source. The distance of the extraction electrode and the plasma electrode can be change 28- 54 mm. As a result of a beam test with He2+, the transmission efficiency of FC2-FC3 increased to 93% when the distance of extraction electrode and plasma electrode was changed.

Create an electron test bench for the proton CARA. An accelerating electron test will be conducted on the testbench using a mirror coil and plasma chamber for the RCNP ECR ion source and a 2.45 GHz power supply. Simulating the electron testbench by Opal, it was found that 2 keV electrons could be accelerated to 25 keV.

A cyclotron originally has an excellent energy efficiency, defined by a ratio of beam power to operation power, because a cyclotron is a compact machine consisting of a minimum number of magnets and RF resonators. We are now designing and developing a high intensity compact cyclotron with energy efficiency of 30 % or more to provide mA-order intense beams of proton, deuteron, 4 He2+, H2 +, H- , D- . The key technologies to realize such a high-energy efficiency cyclotron are production of several tens to 100 mA ion beams by positive and negative ion sources, enhancement of high intensity beam transmission and injection efficiency from LEBT to a center region of a cyclotron, improvement of a charge stripping extraction system for a negative intense beam, maximization of energy efficiency of a cyclotron by reducing power consumption in magnet and RF resonator systems. The high energy-efficiency cyclotron will be applied for mass production of RIs and secondarily produced intense neutron flux for BNCT and neutron-induced RI production. In this paper, the conceptual design of a high intensity compact cyclotron to improve energy efficiency is presented.

We have investigated the feasibility of acceleration of a negative deuterium beam with a current of 100 µA to an energy of 25 MeV using the AVF cyclotron in cyclotron and radioisotope center and the extraction with a stripping foil. The simulation was performed with the code OPAL which can track particles with three-dimensional space charge. The isochronous magnetic field was calculated with the field map of the AVF cyclotron in Takasaki advanced radiation research institute. The current in the main coil and the position of the stripping foil was determined by searching a reference trajectory. The transmission from the central region to the exit of the cyclotron was surveyed, changing the initial distribution and the current.

Purification is essential before differentiating human induced pluripotent stem cells (hiPSCs) into cells that fully express particular differentiation marker genes. High-quality iPSC clones are typically purified through gene expression profiling or visual inspection of the cell morphology; however, the relationship between the two methods remains unclear. We investigated the relationship between gene expression levels and morphology by analyzing live-cell phase-contrast images and mRNA profiles collected during the purification process. We employed this data and an unsupervised image feature extraction method to build a model that predicts gene expression levels from morphology. As a benchmark, we confirmed that the method can predict the gene expression levels from tissue images for cancer genes, performing as well as state-of-the-art methods. We then applied the method to iPSCs and identified two genes that are well-predicted from cell morphology. Although strong batch effects resulting from the reprogramming process preclude the ability to use the same model to predict across batches, prediction within a reprogramming batch is sufficiently robust to provide a practical approach for estimating expression levels of a few genes and monitoring the purification process.

In recent years, an accelerator-based neutron source that replaces a nuclear reactor is being developed, and it is required to further increase the intensity of the accelerator. The automatic cyclotron resonance acceleration method is one of the acceleration methods that has succeeded in accelerating high-intensity electrons of 20 A with low energy up to about 2 MeV. The automatic cyclotron resonance acceleration method is a method in which an electric field rotating at the same angular velocity as a charged particle rotating in a magnetic field is generated and the charged particle is always accelerated in the same direction as the rotating direction. We apply the cyclotron auto-resonance acceleration to protons and aim to develop a proton accelerator that accelerates high-current protons to several tens MeV. Since the cyclotron resonance frequency is proportional to the magnetic flux density and inversely proportional to the mass of the particle, generation of a strong magnetic field is the key to realizing a cyclotron resonance accelerator for a proton with a mass of 2000 times that of an electron. A coil system using a high temperature superconducting wire and a resonant cavity for high frequency TE111 mode were designed by finite element electromagnetic field analysis using OPERA-3D to design an electromagnetic field with a static magnetic field of 8 T and circularly polarized light of 121 MHz. went. Furthermore, the behavior of the proton beam in this static magnetic field and electromagnetic field was calculated by OPAL, and the proton acceleration up to 30 MeV was confirmed. It was also shown that the charge contained in the proton bunch can be increased and the beam can be accelerated with a sufficiently small lateral spread even for a beam equivalent to 100 mA. In this presentation, we will present the calculation of magnetic field and resonant cavity, and the calculation result of proton orbit in the electromagnetic field.

Neutron flux per pulse reached world record at neutron source in Japan Proton Accelerator Research Complex (J-PARC). In the J-PARC, mercury target system is used as a spallation neutron source. A t...

The structure of a neutron-rich ^{25}F nucleus is investigated by a quasifree (p,2p) knockout reaction at 270A MeV in inverse kinematics. The sum of spectroscopic factors of π0d_{5/2} orbital is found to be 1.0±0.3. However, the spectroscopic factor with residual ^{24}O nucleus being in the ground state is found to be only 0.36±0.13, while those in the excited state is 0.65±0.25. The result shows that the ^{24}O core of ^{25}F nucleus significantly differs from a free ^{24}O nucleus, and the core consists of ∼35% ^{24}O_{g.s.}. and ∼65% excited ^{24}O. The result may infer that the addition of the 0d_{5/2} proton considerably changes neutron structure in ^{25}F from that in ^{24}O, which could be a possible mechanism responsible for the oxygen dripline anomaly.

A high position resolution neutron detector for time-of-flight measurements is being developed to measure the ( p , p n ) reaction in inverse kinematics with an excitation energy resolution of 1 MeV at the RIKEN RI Beam Factory. In this study, a new method based on the segmentation of the neutron detector part is employed to achieve a position resolution on the order of mm with a prototype neutron detector. The prototype detector consists of 8 × 8 scintillating fibers, two multi-anode photomultiplier tubes (PMTs) and two light guides. The scintillating fibers have a cross sectional area of 3 . 75 × 3 . 75 mm 2 . The prototype’s performance is studied using the neutron and proton beams provided at the Cyclotron and Radioisotope Center (CYRIC), Tohoku University and the Research Center for Nuclear Physics (RCNP), Osaka University. It is confirmed that the hit pattern analysis correctly recognizes the neutron detection position within the fiber size of 3.75 mm. The obtained TOF resolution of 350 ps (FWHM), lateral position resolution of 2.5 mm (FWHM), and longitudinal position resolution of 50–60 mm (FWHM) satisfy the requirements to achieve an excitation energy resolution of 1 MeV. The typical detection efficiency is ∼ 2.0% for a neutron with a kinetic energy of 50–200 MeV. The detailed investigation of the detection efficiency in conjunction with the neutron hit position reveals the existence of the non-uniformity of the efficiency. It is shown that the non-uniformity can be mitigated by reducing the threshold level, and by increasing the detector size. For a larger neutron detector, based on the design of the prototype detector, the non-uniformity will thus be negligible.

A mercury target vessel made of 316L SS is damaged due to the cavitation caused by the pressure waves in mercury. Cavitation damage reduces the structural integrity of the target front, called "beam window", being major factor to determine the lifetime of target vessel. Aiming at mitigating the cavitation damage by faster mercury flow in narrow channel, we employed a target vessel with a double-walled structure at the beam window along with a gas microbubbles injection. After operating the double-walled target vessel with a beam power of 300 to 500 kW, we cut out the beam window using an annular cutter to examine the damage inside it, and found that damages with maximum pit depth of approximately 25 $\mu$m distributed in a belt on the specimen facing narrow channel. Furthermore, numerical simulation result showed that the distribution of negative pressure period from beam injection to 1 ms was correlated with the damage distribution in the narrow channel. It was suggested that the cavitation induced by relatively short negative pressure period contributed to the damage formation., J-PARCの核破砕中性子源の水銀ターゲット容器(SUS316L製)は、ビーム窓と呼ばれる厚さ3mmの先端部分が、陽子線励起圧力波よるキャビテーションにより壊食損傷する。この損傷は容器の構造健全性を低下させ、容器の寿命の決定因子となっている。我々は、2014年からキャビテーション損傷及びそれを誘発する圧力波を低減するために、気泡注入に加えて狭隘流路を設置することで、ビーム窓の水銀流速を速める2重壁構造を採用し、300$\sim$500kWの強度で運転を行った。使用済みの容器を切断し、内壁を観察した結果、狭隘流路の内側で最大深さ約25$\mu$mの帯状の損傷が観測された。この原因を調べるために、負圧の持続時間に着目した圧力波伝ぱ解析を実施した結果、ビーム入射直後から1msまでに生じる負圧の持続する時間をマッピングした結果と、形成された損傷の分布がよく対応しており、比較的短時間の負圧によって生じるキャビテーションが損傷形成に寄与していることを示唆した。

An examination of the structural integrity and defects of a fabricated mercury target vessel for Japan Proton Accelerator Research Complex (J-PARC) spallation neutron source is presented. Ultrasonic testing (UT) and radiographic testing (RT) were employed as nondestructive inspection methods. The mercury target vessel is composed of SUS316L stainless steel and was designed with multi-walled structures consisting of double-guard vessels with thin walls of 3-mm thickness and assembled by tungsten inert gas welding. The mercury target vessel has complex characteristic, and the weld defect for the thin walls is often very difficult to detect using conventional UT techniques. To overcome this barrier, we employed two new UT techniques, namely 1) immersion ultrasonic with a 50-MHz ultrasonic probe and 2) phased arrays ultrasonic with the full matrix capture (FMC) and the total focusing method (TFM). The examination revealed the formation of small defects and cracks wherein the wall thickness was less than 6 mm. Therefore, new UT techniques are useful for evaluating the structural integrity and defects of the new fabricated mercury vessels. The design and the fabrication process of the mercury target vessel was also evaluated and improved in this study. The use of wire electric discharge machining (EDM) in the fabrication process is desirable to reduce the amount of welding and subsequent welding deformation. The roughness and chemical compositions of the processed surface layer by wire EDM were also examined. The oxide layer was perfectly removed by two-step chemical polishing, and the chemical composition of the layer was analyzed using energy dispersive X-ray spectrometry. In addition, the surface roughness was reduced after polishing to enhance fatigue life and minimize internal defects caused by welding.

The spallation neutron source at the Japan Proton Accelerator Research Complex (J-PARC) mercury target vessel is used for various materials science studies, work is underway to achieve stable operation at 1 MW. This is very important for enhancing the structural integrity and durability of the target vessel, which is being developed for 1 MW operation. In the present study, to reduce thermal stress and relax stress concentrations more effectively in the existing target vessel in J-PARC, an optimization approach called the Taguchi method (TM) is applied to thermo-mechanical analysis. The ribs and their relative parameters, as well as the thickness of the mercury vessel and shrouds, were selected as important design parameters for this investigation. According to the analytical results of 18 model types designed using the TM, the optimal design was determined. It is characterized by discrete ribs and a thicker vessel wall than the current design. The maximum thermal stresses in the mercury vessel and the outer shroud were reduced by 14% and 15%, respectively. Furthermore, it was indicated that variations in rib width, left/right rib intervals, and shroud thickness could influence the maximum thermal stress performance. It is therefore concluded that the TM was useful for optimizing the structure of the target vessel and to reduce the thermal stress in a small number of calculation cases.

We present a precise measurement of 3He analyzing powers for p-3He elastic scattering with the polarized 3He target at 50, 65, 70, and 100 MeV. The data at 65 and 70 MeV are compared with the theoretical predictions based on the modern nucleon-nucleon potentials. Large discrepancies between the data and the predictions are clearly seen at the angles where the 3He analyzing power takes the minimum and maximum values, which are not explained by Δ-isobar effects.

Japan Proton Accelerator Research Complex experienced failures of two mercury targets, which were Target #5 and #7, in 2015 when the facility was operating with a proton beam power of 500 kW. The failures involved coolant water leak from the water shroud. In this paper, we investigate the root cause of the Target #5 failure. The results of the visual inspections, mockup tests, and analytical evaluations suggested that the water leak was caused by the possible combination of two incidents. One was the diffusion bonding failure due to the large thermal stress induced by welding of the bolt head during the fabrication process, and the other was the thermal fatigue failure of the seal weld due to the repetitive beam shutdown during beam operation. Though the investigation into the root cause of the Target #7 failure is still going on, these target failures point to the importance of eliminating initial defects and the need to secure the rigidity and stability of welded structures. The next mercury tar...

Activation cross-sections for the natW(d,x)181,182 m,182 g,183,184m,184g,184g(cum),186gRe, 187W and 182g+m+nTa nuclear reactions were measured from the respective thresholds up to 38 MeV by using a stacked-foil activation technique combined with HPGe γ-ray spectrometry. The results are compared with the available literature data and theoretical data extracted from the TENDL-2015 library, and found only a partial agreement among them. Independent cross-sections for the natW(d,x)182g+m+nTa reactions are reported here for the first time. Physical thick target yields for the investigated reaction products were deduced from the measured cross-sections and compared with the directly measured yields found in the literature. The deduced yield curves indicate that a typical irradiation of an enriched 186W target with 100 µA current from a low energy (

We present a precise measurement of the cross section, proton and 3He analyzing powers, and spin correlation coefficient Cy,y for the p-3He elastic scattering near 65 MeV, and comparison with rigorous four-nucleon scattering calculations based on realistic nuclear potentials and a model with Δ-isobar excitation. Clear discrepancies are seen in some of the measured observables in the regime around the cross section minimum. Theoretical predictions using scaling relations between the calculated cross section and the 3He binding energy are not successful in reproducing the data. Large sensitivity to the NN potentials and rather small Δ-isobar effects in the calculated cross section are noticed as different features from those in the deuteron-proton elastic scattering. The results obtained above indicate that p-3He scattering at intermediate energies is an excellent tool to explore the nuclear interactions not accessible by the three-nucleon scattering.

A new compact electron-beam ion source (EBIS) with a low-energy hollow electron beam has been designed to produce ions for use in heavy-ion therapy. Numerical analyses of the electron beam using the three-dimensional particle-in-cell method determine the appropriate shape of the inner electrodes to realize a compact size and a sufficient number of confined ions for heavy-ion therapy. The analyses also show that the undesirable instability of the hollow electron beam is mitigated by the reflection mode with an electron repeller. Experimental tests were performed on the assembled EBIS to assess the validity of its design. The results of an electron-beam test show that the electrodes have been designed appropriately. Additionally, the results of an ion-beam test show that ions can be produced and confined in the newly developed compact EBIS and the number of extracted ions is just shy of the target value, showing the prospects of modifications aimed at realizing a compact EBIS specialized for the production of ions used in heavy-ion therapy.

A liquid mercury target for the pulsed spallation neutron source is installed at the J-PARC. The liquid mercury is enclosed within a multi-walled stainless-steel vessel. When the highly intense proton beams hit the target at 25 Hz, pressure waves are generated by the rapid thermal expansion of the mercury. The pressure waves causes severe erosion damage on the interior, mercury-facing surface, owing to the cavitation, as well as imposing cyclic impact on the vessel walls. A target diagnostic system, consisting of a laser Doppler vibrometer (LDV) and a microphone, has been installed to remotely investigate the structural integrity of the target vessel in a high-radiation environment. In this study, to investigate the applicability of the sound measurement for the alternative method of the LDV diagnostic system of the target vessel, the correlation between the proton-beam-induced sound and the operational conditions (the proton beam power, the beam profile, and the gas flow rate for injecting microbubbles) was evaluated. The results showed that the sound propagation through the piping and the gap in the radiation shield was well correlated with the operational conditions as well as the LDV results.

Mercury target vessel in the JSNS, which is made of 316L SS, is damaged owing to the pressure wave-induced cavitation resulting from the proton beam bombardment. The cavitation damage decreases the structural integrity of the target vessel and is currently a dominant factor to decide the service life in compared with the radiation damage. Injecting microbubbles into mercury is one of the prospective techniques to mitigate the pressure waves and cavitation damage. In the JSNS, a microbubble generator with a gas circulation system was installed and has been operated since October 2012. The effects of microbubble injection into mercury on pressure wave mitigation were studied using a laser Doppler vibrometer. The result showed that the vibrational velocity of the target vessel is clearly reduced according to the increase of void fraction. An average peak vibrational velocity under 340 kW operation with the void fraction of 0.1\% was reduced to 1/4 of that without injecting microbubbles., J-PARCの核破砕中性子源(JSNS)水銀ターゲット容器は、陽子線入射励起圧力波により励起されるキャビテーションによる損傷を受ける。キャビテーションによる損傷は、容器の構造健全性を低下させるため現在のところ容器の交換寿命を決める支配因子となっている。圧力波及びキャビテーションによる損傷を低減するためには、水銀中にガスマイクロバブルを注入することが効果的な手法である。JSNSでは、ガスマイクロバブルを注入するためのシステムを2012年10月に設置し、レーザードップラー振動計を用いて容器の振動をモニタリングすることによって水銀中へのバブル注入の効果をした。その結果、振動速度は気泡注入量の増加に伴って減少することを確認した。また長期間の運転では、気泡注入によって平均でバブル注入無しの1/4程度の振動速度を維持した。

International audience; The dependence of the single-particle strength on the difference between proton and neutron separation energies is studied for oxygen isotopes in a wide range of isospins. The cross sections of the quasi-free (p, 2p) reaction on 14,16,18,22,24O were measured at intermediate energies. The measured cross sections are compared to predictions based on the distorted wave impulse approximation and shell-model psd valence-space spectroscopic factors. The reduction factors, which are the ratio of the experimental cross sections to the theoretical predictions, show no apparent dependence on the proton–neutron separation energy difference. The result is compatible with the result of the (e, e p) reaction on stable targets and with the predictions of recent ab initio calculations.

At the Japan Proton Accelerator Research Complex (J-PARC), a pulsed spallation neutron source provides neutrons with high intensity and narrow pulse width pulse to promote researches on a variety of science in the Materials and Life Science Experimental Facility (MLF). It was designed to be driven by a proton beam with an energy of 3 GeV, a power of 1 MW at a repetition rate of 25 Hz, that is world’s highest power level. It is still on the way towards the goal to accomplish the operation with a 1 MW proton beam. In this review, distinctive features of the target-moderator-reflector system of the pulsed spallation neutron source are presented.

A lead bismuth eutectic (LBE) spallation target will be installed in the Target Test Facility (TEF-T) in the Japan Proton Accelerator Research Complex (J-PARC). The spallation target vessel filled with LBE is made of type 316L stainless steel. However, various damages, such as erosion/corrosion damage and liquid metal embrittlement caused by contact with flowing LBE at high temperature, and irradiation hardening caused by protons and neutrons, may be inflicted on the target vessel, which will deteriorate the steel and might break the vessel. To monitor the target vessel for prevention of an accident, an ultrasonic technique has been proposed to establish off-line evaluation for estimating vessel material status during the target maintenance period. Basic R&D must be carried out to clarify the dependency of ultrasonic wave propagation behavior on material microstructures and obtain fundamental knowledge. As a first step, ultrasonic waves scattered by the grains of type 316L stainless steel are investigated using new experimental and numerical approaches in the present study. The results show that the grain size can be evaluated exactly and quantitatively by calculating the attenuation coefficient of the ultrasonic waves scattered by the grains. The results also show that the scattering regimes of ultrasonic waves depend heavily on the ratio of wavelength to average grain size, and are dominated by grains of extraordinarily large size along the wave propagation path.

The liquid mercury target system for the Japan Spallation Neutron Source (JSNS) began operating in May 2008. A mercury target vessel composed of type 316L stainless steel suffers radiation damage in the proton and neutron environment. In addition to this damage, the inner wall of the target vessel in contact with mercury is damaged by cavitation-induced erosion, which is caused by rarefied pressure waves. The target vessel was replaced with a new target in November 2011, because the pneumatic bellow type flange was damaged during the Great East Japan Earthquake, that occurred on March 11, 2011. Before replacing the target, 50 mm diameter disk specimens were cut from the beam window of the target vessel in order to investigate the cavitation damage inside the target vessel and to evaluate the change in the mechanical properties due to radiation damage. A video camera was used to inspect the inside of the target vessel and no flow induced erosion damage was detected on the flow guide by visual inspection. Cavitation damage from the proton pulse was concentrated at the center and approximately 15 mm from the center of the beam window. In addition, the depth of the cavitation damage was quantitatively measured using a laser profilometer and a metallurgical surface replica. Based on the detailed measurements, it was concluded that the eroded damage depth of the beam window was 250 μm after 475 MW h of operation.

A double-walled liquid mercury target vessel, which consists of outer and inner walls, is being globally developed for MW-class spallation neutron sources. When proton beams bombard a mercury target, pressure waves are generated due to the rapid thermal heat deposition. These pressure waves trigger impulsive vibrations in the mercury vessel, and cause cavitation damage to the inner wall of the vessel. In this study, the dependency of the vibration behavior of the mercury vessel on the damage is systematically investigated through numerical simulations and experiments, for inner wall damage characterized by hole diameters of 1, 5, 10, 20, and 40 mm. A method referred to as wavelet differential analysis is developed, and a parameter referred to as average intensity is derived for a quantitative damage evaluation. Both the numerical simulation and experimental results show that the average intensity is damage-sensitive and depends on the damage feature size. The critical damage hole diameter is estimated to be 10 mm during damage evaluation.

The ion-production efficiency of a newly developed singly charged ion source (SCIS) has been investigated to discuss the possibility of it being used in an isotope separation on-line system that provides 11C ions for heavy-ion cancer therapy with simultaneous verification of the irradiation field using positron emission tomography. The SCIS uses a low-energy hollow electron beam to produce singly charged carbon ions efficiently. To deliver sufficient 11C ions to the treatment room from a limited amount of 11C molecules, which are produced from a boron compound target and proton-beam irradiation via the 11B(p,n)11C reaction, the SCIS must have high ion-production efficiency. To realize this high efficiency, the SCIS was designed using a three-dimensional particle-in-cell code in previous work. With the fabricated SCIS, we performed experiments to measure the efficiency of producing CO+2 ions from nonradioactive 12CO2 molecules and C+ ions from nonradioactive 12CH4 molecules. We found that the SCIS achieved efficiencies of εC+=4×10−3 (0.4%) for C+ production and εCO+2=0.107 (10.7%) for CO+2 production.

Ultrasonic waves generated by a pulsed Nd-YAG laser are being adopted to evaluate the cavitation damage, so-called pitting, caused by proton beam injection in pulsed neutron sources. The wave’s propagation behavior depends on the density and depth of the pits. To quantitatively understand the relationship between the pits and the wave propagation behavior, the artificial pits were imposed on the evaluated specimen while controlling the density and depth. A laser Doppler vibrometer was used to remotely detect the ultrasonic waves generated by the Nd-YAG laser. It was found that the two parameters, namely, the maximum negative peak value and the attenuation of received waveforms were useful for quantitatively evaluating the damage. As a result, cavitation damage with a peak-to-peak roughness of more than 15µm was successfully evaluated. [doi:10.2320/matertrans.I-M2014813]

We are developing a new nuclear laser spectroscopic technique for the study of nuclear structure that can be applied to short-lived low-yield atoms with unstable nuclei. The method utilizes superfluid helium (He II) as a trapping medium for high-energy ion beams. A liquid helium cryostat with optical windows is a key apparatus for this type of experiment. We describe the design and the performance of the cryostat which is developed for the present project.

We have been developing a novel nuclear laser spectroscopy method “OROCHI” for determining spins and moments of exotic radioisotopes. In this method, we use superfluid helium as a stopping material of energetic radioisotope beams and then stopped radioisotope atoms are subjected to in situ laser spectroscopy in superfluid helium. To confirm the feasibility of this method for rare radioisotopes, we carried out a test experiment using a 85 Rb beam. In this experiment, we have successfully measured the Zeeman resonance signals from the 85 Rb atoms stopped in superfluid helium by laser-RF double resonance spectroscopy. This method is efficient for the measurement of spins and moments of more exotic nuclei.

Proton polarization at room temperature, produced in a p-terphenyl crystal by using electron population difference in a photo-excited triplet state of pentacene, was enhanced by utilizing an intense laser with an average power of 1.5 W. It was shown that keeping the sample temperature below 300 K is critically important to prevent the rise of the spin–lattice relaxation rate caused by the laser heating. It is also reported that the magnitude of proton polarization strongly depends on the time structure of the laser pulse such as its width and the time interval between them.

In order to investigate the structure of exotic nuclei with extremely low yields by measuring nuclear spins and moments, a new laser spectroscopy technique – “OROCHI” (Optical Radioisotopes Observation in Condensed Helium as Ion-catcher) has been proposed in recent years. The feasibility of this technique has been demonstrated by means of a considerable amount of offline and online studies of various atoms in superfluid helium. For in-situ laser spectroscopy of atoms in He II, trapping atoms in the observation region of laser is a key step. Therefore, a method which enables us to trap accelerated atoms at a precise position in He II is highly needed for performing experiment. In this work, a technique making use of a degrader, two plastic scintillators and a photon detection system is established for checking the stopping position of beam based on the LISE++ calculation. The method has been tested and verified by on-line experiments with the 84 , 85 , 87 Rb beam. Details of the experimental setup, working procedure and testing results of this method are presented.

We developed a prototype laser ionization gas cell with a beam extraction system. This device is for use of PArasitic Laser Ion-Source (PALIS), which will be implemented into RIKEN’s fragment separator, BigRIPS as a part of SLOWRI. Off-line resonant laser ionization for stable Co, Cu, Fe, Ni, Ti, Nb, Sn, In and Pd inside the gas cell, ion extraction and transport to the high-vacuum region via SPIG and QMS have been confirmed (Sonoda et al, Nucl Instrum Meth B 295:1, 2013).

The city of Tokyo, renamed after the Meiji Restoration, developed an urban culture that was a dynamic integration of Edo's highly developed traditions and Meiji renovations, some of which reflected the influence of Western culture. This wide-ranging anthology-including fictional and dramatic works, essays, newspaper articles, political manifestos, and cartoons-tells the story of how the city's literature and arts grew out of an often chaotic and sometimes paradoxical political environment to move toward a consummate Japanese "modernity." Tokyo's downtown audience constituted a market that demanded visuality and spectacle, while the educated uptown favored written, realistic literature. The literary products resulting from these conflicting consumer bases were therefore hybrid entities of old and new technologies. A Tokyo Anthology guides the reader through Japanese literature's journey from classical to spoken, pictocentric to logocentric, and fantastic to realistic-making the novel the dominant form of modern literature. The volume highlights not only familiar masterpieces but also lesser known examples chosen from the city's downtown life and counterculture. Imitating the custom of creative artists of the Edo period, scholars from the United States, Canada, England, and Japan have collaborated in order to produce this intriguing sampling of Meiji works in the best possible translations. The editors have sought out the most reliable first editions of texts, also reproducing most of their original illustrations. With few exceptions the translations presented here are the first in the English language. This rich anthology will be welcomed by students and scholars of Japan studies and by a wide general audience interested in Japan's popular culture, media culture, and literature in translation.

In recent years, the production of radionuclides for Targeted Radionuclide Therapy (TRT) with the NIRS-930 cyclotron has been one of the most important activities in National Institutes for Quantum and Radiological Science and Technology (QST). In the production of 211At, for example, a target material with low melting point is irradiated with a high intensity beam. A vertical beam line have the advantage in irradiation with low-melting-point target. Therefore a vertical beam line has been modified for the production of radionuclides. This line was used for neutron source with beryllium target. The beam intensity and beam energy are important parameters for the effective production of radionuclide for TRT. In order to increase beam intensity, the acceleration phase and injection energy have been optimized by measuring beam phase. The beam energy has been measured by TOF and adjusted by tuning the acceleration frequency. Those studies and improvement are reported., 21st International Conference on Cyclotrons and their Applications