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Section 3.2.1 last sentence, "channels" should be "channel". Section 3.2.2 first sentence "m/r" should be "μ/ρ". Section 3.3 end of 3rd line "form" should be "from".

Imaging bolometers have been studied for ITER to serve as a complementary diagnostic to the resistive bolometers for the measurement of radiated power. Two tangentially viewing InfraRed imaging Video Bolometers (IRVB) could be proposed for an ITER equatorial port, one having a view of the entire plasma cross-section (core viewing) and one tilted down 43 degrees from the horizontal to view the divertor (divertor viewing). The IRVBs have 7 cm (horizontal) by 9 cm (vertical) Pt sensor foils, 6 mm × 6 mm apertures, 15 × 20 pixels and focal lengths of 7.8 cm and 21 cm, respectively. Using SANCO and SOLPS models for a 840 m3 plasma radiating 67.3 MW, synthetic images from the IRVBs are calculated to estimate the maximum signal strengths to be 246 W/m2 and 62 W/m2, respectively. We propagate the X-ray energy spectra from the models through the synthetic diagnostics to give the photon energy spectrum for each IRVB pixel, which are used to calculate the fraction of the power absorbed by the foil as a function of foil thickness. Using a criteria of >95% absorbed power fraction, we selected foil thicknesses of 30 μm and 10 μm, respectively. We used these thicknesses and assumed IR systems having 105 fps, 1024×1280 pixels and sensitivities of 15 mK, to calculate the IRVB sensitivities of 3.19 W/m2 and 1.05 W/m2, and signal to noise ratios of 77 and 59, respectively. Using the Monte Carlo Nuclear Particle code we calculated for the core viewing IRVB the foil heating by neutrons to be 1.0 W/m2 and by gammas to be 117 W/m2. This indicates that countermeasures may be needed to remove the nuclear heating signal.

Photocathodes with negative electron affinity (NEA) characteristics have various advantages, such as small energy spread, high spin polarization, and ultrashort pulsing. Nitride semiconductors, such as GaN and InGaN, are promising materials for NEA photocathodes because their lifetimes are longer than those of other materials. In order to further prolong the lifetime, it is important to better understand the deterioration of NEA characteristics. The adsorption of residual gases and back-bombardment by ionized residual gases shorten the lifetime. Among the adsorbed residual gases, H2O has a significant influence. However, the adsorption structures produced by the reaction with H2O are not comprehensively studied so far. In this study, we investigated adsorption structures that deteriorated the NEA characteristics by exposing InGaN and GaAs to an H2O environment and discussed the differences in their lifetimes. By comparing the temperature-programmed desorption curves with and without H2O exposure, the generation of CsOH was confirmed. The desorption of CsOH demonstrated different photoemission behaviors between InGaN and GaAs results. InGaN recovered its NEA characteristics, whereas GaAs did not. Considering the Cs desorption spectra, it is difficult for an NEA surface on InGaN to change chemically, whereas that for GaAs changes easily. The chemical reactivity of the NEA surface is different for InGaN and GaAs, which contributes to the duration of photoemission. We have attempted to prolong the lifetime of InGaN by recovering its NEA characteristics. We found that InGaN with NEA characteristics can be reused easily without thermal treatment at high temperatures.

The fast deuteron (non-Maxwellian component) diagnostic method, which is based on the higher resolution optical spectroscopic measurement, has been developed as a powerful tool. Owing to a decrease in the D-H charge-exchange cross section, the diagnostic ability of conventional optical diagnostic methods should be improved for ∼MeV energy deuterons. Because the

An energy transfer phenomenon between energetic ions, which cannot be explained only considering the Coulomb scattering process, was observed on a large helical device (LHD). This phenomenon often occurs in fusion reactivity enhancement and fast-ion slowing-down process that can be observed as a delay in the decay time of the D(d,n)3He neutron generation rate. The transferred energy required to induce such a reactivity enhancement or delay in the fast-ion slowing-down time (neutron decay time) was examined based on the Boltzmann−Fokker−Planck analysis in which a discrete energy transfer process, called nuclear elastic scattering (NES), is included. It was shown that even though the cross section of the NES is smaller than that of the Coulomb scattering, enough knock-on population appears in the energetic region in ion distribution function to induce the observable NES effects; thus, enough energy is transferred from beam ions to fast component of bulk ion distribution function indirectly and the transferred energy per unit time via NES is comparable to the Coulomb scattering rate. This study analytically demonstrates that the observed phenomena on LHD can be explained smoothly by considering the alternative indirect energy transfer channel between energetic ions, which can be comparable with the one via Coulomb scattering.

The vertical neutron camera (VNC) has been developed to measure neutron emission profile in deuterium plasmas of the large helical device (LHD). The experiment on spatial resolution evaluation for VNC was carried out in November 2016 by using a 252 Cf neutron source of 800 MBq. The neutron source was introduced into the LHD vacuum vessel through an aluminum pipe from an upper diagnostics port to the equatorial plane. The source was placed at the following two positions. The first position is just on the cylindrical collimator axis, and the second position is in the middle of two neighboring collimator axes. The stilbene scintillation detectors are aligned radially at the collimator end to detect unscattered fast-neutrons generated in a deuterium plasma. The 3-D neutron transport calculations by using a general-purpose Monte Carlo N-particle code 6 reproduced the experimentally obtained neutron counting rate, indicating that VNC has sufficient spatial resolution and the crosstalk between two neighboring collimators is a fairly small fraction. It is expected that the VNC on LHD will function as a tool for the study on the radial transport of energetic ions.

Dilution refrigerators are an important tool used in solid state and quantum fluid physics for cooling to temperatures below 0.3 K. Conventional dilution refrigerators consume a lot of liquid helium, which has to be recharged in a helium bath every few days. Cryogen-free dilution refrigerators, however, do not use liquid helium and then automatic operation by electricity can be possible from room temperature to the mK region. In near future, therefore, most conventional dilution refrigerators will be replaced by cryogen-free refrigerators because they are easy to operate, do not require maintenance and do not consume helium. We have developed two types of cryogen-free dilution refrigerator. One is directly cooled by a pulse tube refrigerator in the same cryostat using copper thin wires as a thermal link, and the other is cooled by a separate Gifford McMahon refrigerator using circulating helium gas through a flexible syphon tube. The latter has been developed as a vibration-free cryogen-free dilution refrigerator. These two types of cryogen-free dilution refrigerator are compared considering several key points: base temperature, precooling time, minimum temperature and vibration amplitude.

SlimCS is the conceptual design of a compact fusion DEMO plant assuming technologies foreseeable in 2020–2030s. For continuity of blanket technology from the Japanese ITER-TBM, the prime option of blanket is water-cooled solid breeder with Li 2 TiO 3 (or Li 4 SiO 4 ) and Be. A reduced-activation ferritic–martensitic steel (RAFM) and subcritical water are chosen as the structural material and coolant, respectively. The reactor has somewhat complex torus configuration with a sector-wide conducting plate slipped in between the replaceable (front) and permanent (back) blanket. In order to allow flexibility of maintenance in such a complex configuration, sector transport hot cell maintenance scheme is adopted. This paper describes characteristics of SlimCS with a focus on materials selection.

The concept for a compact DEMO reactor named 'SlimCS' is presented. Distinctive features of the concept are low aspect ratio (A = 2.6) and use of a reduced-size centre solenoid (CS) which has the function of plasma shaping rather than poloidal flux supply. The reduced-size CS enables us to introduce a thin toroidal field coil system which contributes to reducing the weight and perhaps lessening the construction cost. Low-A has merits of vertical stability for high elongation (κ) and high normalized beta (βN), which leads to a high power density with reasonable physics requirements. This is because high κ facilitates high nGW (because of an increase in Ip), which allows efficient use of the capacity of high βN. From an engineering aspect, low-A may ensure ease in designing blanket modules robust to electromagnetic forces acting on disruptions. Thus, a superconducting low-A tokamak reactor such as SlimCS can be a promising DEMO concept with physics and engineering advantages.

The confinement degradation and transport of energetic ions due to Alfven eigenmodes (AEs) destabilized by negative-ion-based neutral beam injection are quantitatively evaluated for the first time. AEs were observed in JT-60U weak shear plasmas with frequencies sweeping up to 30–50 kHz on a time scale of a few hundred milliseconds as the safety factor at the plasma centre, q(0), decreases from 1.75 to 1.5. Then as q(0) decreases from 1.5 to 1.25 in about 600 ms, the AE frequencies are saturated and the AEs are identified as the TAEs. The measured total neutron emission rate (Sn) in the presence of these AEs is compared with that predicted by classical theory. As a result, the confinement degradation of energetic ions is confirmed and the reduction rate in Sn is largest when AEs are destabilized and are located at the large fast ion pressure gradient region in the plasma core. In order to investigate the energetic ion transport due to these AEs, line-integrated neutron emission profiles measured with a large neutron collimator array are compared with the classical confinement calculations. It is found that energetic ions are transported from the plasma core region to the outer region due to these AEs. Furthermore, changes in the energy distribution of charge exchange energetic neutral particle fluxes suggest that the radial energetic ion transport is due to the resonance interaction between the energetic ions and the AEs.

In order to support the operation of ITER and the planned experimental programme an extensive set of plasma and first wall measurements will be required. The number and type of required measurements will be similar to those made on the present-day large tokamaks while the specification of the measurements—time and spatial resolutions, etc—will in some cases be more stringent. Many of the measurements will be used in the real time control of the plasma driving a requirement for very high reliability in the systems (diagnostics) that provide the measurements. The implementation of diagnostic systems on ITER is a substantial challenge. Because of the harsh environment (high levels of neutron and gamma fluxes, neutron heating, particle bombardment) diagnostic system selection and design has to cope with a range of phenomena not previously encountered in diagnostic design. Extensive design and R&D is needed to prepare the systems. In some cases the environmental difficulties are so severe that new diagnostic techniques are required. a Author to whom any correspondence should be addressed.

Confinement degradation of energetic ions due to Alfven eigenmodes (AEs) has been investigated with negative ion based neutral beam injection at ~370 keV into JT-60U weak shear plasmas. AEs with a rapid frequency sweeping and then saturation as the minimum value of the safety factor decreases have been observed. This frequency behaviour can be explained by the reversed-shear induced AE (RSAE) and the transition from RSAEs to the toroidicity-induced AEs (TAEs). The associated change in the charge exchange neutral particle flux suggests energetic ion transport due to these AEs. The total neutron emission reduction rate in the presence of these AEs is evaluated by calculation using the orbit following Monte-Carlo code taking into account the change in bulk plasmas. The evaluation indicates confinement of energetic ions is degraded due to these AEs. In particular, it is found that the confinement degradation of energetic ions is maximum during the transition from RSAEs to TAEs and the maximum reduction rate (ΔSn/Sn)MAX is estimated to be ~45%.

For the analyses of gate insulating materials of thin silicon oxy-nitride (SiON) and dielectric films, SIMS is one of the available tool along with TEM and ESCA, etc. Especially, to investigate the distribution of dopant in the thin films, SIMS is appreciably effective in these techniques because of its depth profiling capability and high sensitivity. One of the problem occurring in this SIMS measurement is the change of secondary ion yield at the interface as well as in the layers with different chemical composition. To solve this problem, some groups have researched the phenomenon for SiO 2 /Si interface [W. Vandervorst, T. Janssens, R. Loo, M. Caymax, I. Peytier, R. Lindsay, J. Fruhauf, A. Bergmaier, G. Dollinger, Appl. Surf. Sci. 203-204 (2003) 371-376; S. Hayashi, K.Yanagihara, Appl. Surf. Sci. 203-204 (2003) 339-342; M. Barozzi, D. Giubertoni, M.Anderle, M. Bersani, Appl. Surf. Sci. 231-232 (2004) 632-635; T.H. Buyuklimanli, J.W. Marino, S.W. Novak, Appl. Surf. Sci. 231-232 (2004) 636-639]. In the present study, profiles of boron and matrix elements in the Si/SiON layers on Si substrate have been investigated. The sensitivity change of Si and B profiles in SiON layer become smaller by using oxygen flood than those without oxygen flood for both O 2 + and Cs + beam. At the range of 0-25 at.% of N composition, 11 B dosimetry in SiON layer implanted through amorphous Si depends on N composition. This trend could be caused by the sensitivity change of 11 B, or it indicates real 11 B concentration change in SiON lyaer. N areal density determined by Cs + SIMS with oxygen flooding also shows linear relationship with N composition estimated by XPS.

To investigate energetic ion transport induced by bursting modes in the frequency range of Alfven eigenmodes, which is called abrupt large-amplitude events (ALEs) driven by negative-ion-based neutral beam (N-NB) injection, neutron emission profile measurement and charge exchange (CX) neutral particle (flux) measurement using a natural diamond detector have been performed simultaneously in JT-60U. It is found from the CX neutral particle (flux) measurement that energetic neutral particles in a limited energy range (100–370 keV) are enhanced due to ALEs, and the neutron radial profile is flattened. The change in the energetic ion density profile inferred from these measurements indicates that ALEs expel energetic ions from the core region of the plasma and induce both redistribution and loss of energetic ions. It has been shown that the energy range of transported energetic ions is consistent with a resonance condition between energetic ions and ALEs, and the energetic ion transport results from the resonant interaction between energetic ions and ALEs. Further, a fraction of the energetic ion loss has been quantitatively estimated to be ~4%.

We have fabricated vertically-stacked interface-treated Josephson junctions using YbBa/sub 2/Cu/sub 3/O/sub 7-x/ (YbBCO) as a counter electrode for improving the uniformity. We used YBCO for the base electrode. Most of the junctions fabricated on one chip exhibited resistively-shunted-junction (RSJ) characteristics. The properties of the junctions at 4.2 K were as follows: J/sub c/=1.0/spl times/10/sup 3/ A/cm/sup 2/ with a 1/spl sigma/ spread of 6.9%, and I/sub c/R/sub n/=0.5 mV with a 1/spl sigma/ spread of 5.4%. These spreads were improved compared with those of junctions with YBCO as a counter electrode. Furthermore, the normal conductance G/sub n/ of the junctions with the YbBCO counter electrode was independent of the temperature. Such characteristics have not been obtained for YBCO vertically-stacked interface-treated junctions. We speculate that this difference is attributed to the lattice mismatch between base-and counter-electrodes.

In SIMS analysis of III-V compound semi-conductors with different matrix composition multi-layer, quantification of impurity or dopant is complex due to matrix effect. When we investigated relative sensitivity factor (RSF) of Si (n-type dopant) in each matrix and calculated RSF ratio, it seems to vary depending on offset voltage to sample. In this paper, we have investigated RSF of Si in various III-V compound semi-conductor. In acquiring RSF of Si, offset voltage on sample during the measurement and reference intensity (IR) in RSF calculation were adopted as parameter. In the case of some matrix sample, energy distribution was examined, and it proved that the energy distribution of Si and V group element (P and As) is concerned in RSF ratio. RSF ratio does not depend on offset voltage if IR in RSF calculation is employed in the same matrix as that of Si. As in the case with previous study, the matrix effect of Si in InP and InGaAs reveals at the peak of energy distribution. Copyright © 2012 John Wiley & Sons, Ltd.

The current from copper electrodes treated by four different types of surface cleaning procedures was measured under DC high field gradient condition. The best results were obtained by using the electrode rinsed with ultra-pure water after diamond turning. A field gradient of 47 MV/m was achieved with dark current at the level of 1 nA, and the microscopic field enhancement factor was estimated to be a very low value of 56. The dark current from this electrode was dependent only on the field gradient at the cathode and not affected by the total voltage applied to the gap. In this case the surface would be covered by a Cu2O layer, which creates few secondary ions by the electron bombardment. On the other hand, a large total voltage effect and a large vacuum increase were observed for the electro-polished electrode. Cu(OH)2, which would be formed at the copper surface during the electro-polishing process, would emit H2O molecules during the electron bombardment.

The research to develop the polarized electron source required by future linear colliders has been conducted by our collaboration. Recent advances in settling three difficult problems to realize the high polarization and high quantum efficiency, the long cathode lifetime and the multi-bunch beam generation are briefly described in this article.

Polarized electron beam with sub-nanosecond multi-bunch structure has been "rst produced from an In-GaAs}AlGaAs strained-layer superlattice photocathode with heavy surface doping. The extracted charge of0.6]1010e~/bunch is determined by the space charge limit of the 50keV gun. The multi-bunch e!ect due to the surfacechargelimitphenomenon,whichispeculiartoanegativeelectrona$nitysurfaceofsemiconductorphotocathode,isnotobserved in the second bunch separated by 2.8ns. We conclude that a superlattice photocathode with a heavily dopedsurface is the best photocathode for the future linear colliders. ( 2000 Elsevier Science B.V. All rights reserved. 1. IntroductionPolarized electron source based on semiconduc-torphotocathodeis expectedto play a very impor-tant role in future linear colliders [1,2]. In order toachieve a high luminosity of &5]1033cm~2s~1,about 80 micro-bunches with a separation time of2.8nsmustbeproducedat150HzrepetitionrateatJapan Linear Collider (JLC). Each bunch mustcontainmorethan2]1010e~(each)()1ns width)at the source [3].The generation of such a high-intensity multi-bunch beam is not easy due to a surface chargelimit (SCL) phenomenon [4,5]. This phenomenonis peculiar to a negative electron a$nity (NEA)surface, which is a key technique for the semicon-ductorphotocathodestoextracttheopticallyexcit-edelectronsintheconductionbandtothevacuum.When a photocathode is illuminated with a high-intensity laser light, the electrons which cannotescape to the vacuum are trapped at the surfaceband bending region. The accumulated surfacecharge prevents electrons in the later portion ofthe pulse from escaping to the vacuum.In order to overcome the SCL problem, weinvestigated the multi-bunch generation using the70keVpolarizedelectronsourcesystemat NagoyaUniversity. It was demonstrated that a super-lattice photocathode (for example, GaAs}AlGaAs

Reed-Solomon (RS) coders are used for error-control coding in many applications such as digital audio, digital TV, software radio, CD players, and wireless and satellite communications. Traditionally, RS coders have been implemented using dedicated hardware. This paper considers software-based implementation of RS codecs. A hardware-software codesign approach is used to design the finite field datapath in a domain-specific digital signal processor (DSP) with low-energy RS codecs application in mind. These datapaths are designed to accommodate programmability with respect to the primitive polynomial as well as the field degree m. A novel heterogeneous digit-serial approach is proposed, where the heterogeneity corresponds to the use of different digit sizes in the multiply-accumulate (MAC) and degree reduction (DEGRED) subarrays. The salient feature of this digit-serial approach is that only the digit cells are implemented in hardware and the finite field multiplications are performed digit-serially in software by dynamically scheduling the internal digit-level operations. Efficient scheduling strategies for digit-serial finite field multiplications are presented and applied to the design of low-energy high-performance RS codecs in software. Significant energy and energy-latency reductions can be achieved using the digit-serial datapaths, as compared with the traditional approach where a combined MAC-DEGRED (parallel multiplier) unit is used. It is concluded that for two-error-correcting RS(n, k) codes over finite field GF(2/sup 8/), datapath containing a parallel MAC unit (of digit size eight) and a DEGRED unit with digit size two (or four) leads to RS codecs with the least energy consumption and energy-latency products; with these datapath architectures and appropriate digit-serial scheduling strategies, more than 60% energy reduction and more than one-third energy-latency reduction can be achieved compared with the parallel multiplication datapath-based approach.

The article provides a comprehensive overview of the history of how signal-processing researchers have been effectively transforming signal-processing algorithms into efficient implementations. Starting from the early days of analog circuits for signal processing, to digital signal processors (DSPs), to application specific DSPs and programmable DSPs, and to the trend of integrating a complete system on a single chip, this article provides a thorough coverage of the past and the present of design and implementation technology for signal processing systems. Moreover, it presents the exciting challenges faced by the study of the design and implementation of current and future signal processing applications. Topics covered include milestones in signal-processing integrated circuits, the past and future of the signal processor, signal processing in consumer applications, and design automation for signal processing.

The several that many fires occurred simultaneously at the time of the Kobe earthquake in 1995 became urban area fires. Thereupon, we analyzed the fire spread situation of urban area fires of Kobe city in this research. We used the data that was obtained by Fire Department of Kobe city and Tokyo Fire Department. The fire data that we analyzed has over about 10,000 m' of bum-out area . It is as a future research theme about the fire spread condition which fire fighting water is considered. The fire spread model that considered bum-out area, fire front length and also the fire spread speed, were examined in this paper.

In this paper, the three-dimensional problem concerning the transient thermal stress is theoretically analysed by considering the thermomechanical coupling effect by means of the Laplace transformation and the generalized Fourier transformation. Numerical evaluation is carried out for the temperature distribution and the thermal stresses in an infinite plate heated by a local heat source that moves with constant velocity on the surface.

Detailed plasma-physics investigations by the use of x-ray-tomography data supported by the fundamental theoretical studies of x-ray-detector responses enhance the importance of x-ray diagnostics for fusion-plasma analyses. However, degradation in responses of semiconductor x-ray detectors after fusion-produced neutron exposure still remains one of the most serious problems in recent fusion experiments even at this time. For the purpose of investigating and characterizing neutron effects on semiconductor x-ray detectors, detection characteristics of n-type silicon semiconductor detectors which are similar to those utilized for x-ray-tomography detectors in the Joint European Torus (JET) tokamak, are studied by the use of synchrotron radiation from a 2.5-GeV positron storage ring at the Photon Factory. The fusion neutronics source (FNS) of Japan Atomic Energy Research Institute is employed as well-calibrated deuterium-tritium (D-T) neutron source with fluences from 10 13 to 10 15 neutrons/cm 2 onto these semiconductor detectors. Degradation in x-ray responses with increasing neutron fluences has been reported; however, our recent detailed investigations of detector responses show nonlinear dependence as a function of the neutron fluence.

The deuterium-tritium (D-T) experimental program on the Tokamak Fusion Test Reactor (TFTR) is underway and routine tritium operations have been established. The technology upgrades made to the TFTR facility have been demonstrated to be sufficient for supporting both operations and maintenance for an extended D-T campaign. To date fusion power has been increased to {approximately}9 MW and several physics results of importance to the D-T reactor regime have been obtained: electron temperature, ion temperature, and plasma stored energy all increase substantially in the D-T regime relative to the D-D regime at the same neutral beam power and comparable limiter conditioning; possible alpha electron heating is indicated and energy confinement improvement with average ion mass is observed; and alpha particle losses appear to be classical with no evidence of TAE mode activity up to the P{sub FUS} {approximately}6 MW level. Instability in the TAE mode frequency range has been observed at P{sub FUS} > 7 MW and its effect on performance is under investigation. Preparations are underway to enhance the alpha particle density further by increasing fusion power and by extending the neutral beam pulse length to permit alpha particle effects of relevance to the ITER regime to be more fullymore » explored.« less

A folded architecture and a digit-serial architecture are proposed for implementation of one- and two-dimensional discrete wavelet transforms. In the one-dimensional folded architecture, the computations of all wavelet levels are folded to the same low-pass and high-pass filters. The number of registers in the folded architecture is minimized by the use of a generalized life time analysis. The converter units are synthesized with a minimum number of registers using forward-backward allocation. The advantage of the folded architecture is low latency and its drawbacks are increased hardware area, less than 100% hardware utilization, and the complex routing and interconnection required by the converters used. These drawbacks are eliminated in the alternate digit-serial architecture at the expense of an increase in the system latency and some constraints on the wordlength. In latency-critical applications, the use of the folded architecture is suggested. If latency is not so critical, the digit-serial architecture should be used. The use of a combined folded and digit-serial architecture is proposed for implementation of two-dimensional discrete wavelet transforms. >

The development of a 275 kV gas-cooled, gas-insulated power transformer with a sound level ideal for an urban area, which depends on SF/sub 6/ gas alone for both insulation and cooling, is described. The design philosophy, technical aspects, rating, and features of a 275 kV 30 MVA transformer are described, and the performance and long-term energization test results are discussed. >

2-endo-Hexadecylamino-2-exo-hydroxymethylnorbornene (1a) was synthesized from 2-acetamidonorbornene-2-carboxylic acid methyl ester (2) in a good overall yield. 2-endo-Hexadecylamino-2, 3-exo-bis(hydroxymethyl)norbornene (1b) was synthesized starting from dimethyl acetamidofumarate based on Diels-Alder strategy. 1a and 1b inhibited protein kinase C at the IC50 values of 2×10-5M and 1×10-5M, respectively, but not protein kinase A at a concentration of 1×10-3M. The structure-activity relationships are discussed.

An experimental study to improve the cooling power of a coaxial pulse tube cryocooler (PTC) has been carried out. The operating temperature was optimized for cooling liquid xenon at around 165–170 K. The PTC has a coaxial configuration with a cylindrical regenerator inside, a hollow‐walled cylindrical pulse tube. The cooling performance obtained was ∼180–200 W at around 165 K, when operated with a 6–6.5 kW GM‐type compressor. For the phase shift between pressure and flow, a simple‐orifice scheme was used, which resulted in stable operation of a long‐term physics experiment. PTCs have now been successfully applied in physics experiments such as MEG and XENON for many years.In order to study flow disturbance inside of a tube, thermometers were placed on an outer cylinder wall to monitor gas temperature inside of a tube. In the original scheme, there is a single gas exhaust line from the pulse tube to an orifice valve and buffer tank. In this study, an additional exhaust line was used to suppress the flow di...

The cyclic creep behaviour under axial tension was quantitatively investigated using non-linear viscoelastic cellulose nitrate heated at 65°C. The instantaneous strains at the instants of loading and unloading for three creep cycles and the creep strain rates during the three creep cycles were found to be influenced by the cycle numbers. However, the effect of the cycle number on the loading process was quite different from that on the unloading process in the cyclic creep deformation. The evaluation of the creep constitutive equations for the loading and unloading processes at one loading cycle deduced in the previous papers is discussed for the cyclic creep deformation. The deduced creep equations give good agreement with the actual observations for the three creep cycles independent of the cycle numbers and of the creep stress levels.

Neutron emission profiles are routinely measured in JT‐60U Tokamak. Stinbene neuron detectors (SNDs), which combine a Stilbene organic crystal scintillation detector (Stilbene detector) with an analog neutron‐gamma pulse shape discrimination (PSD) circuit, have been used to measure neutron flux efficiently. Although the SND has many advantages as a neutron detector, the maximum count rate is limited up to ∼1× 105 counts/s due to the dead time of the analog PSD circuit. To overcome this issue, a digital signal processing (DSP) system using a Flash‐ADC has been developed. In this system, anode signals from the photomultiplier of the Stilbene detector are fed to the Flash ADC and digitized. Then, the PSD between neutrons and gamma–rays are performed using software. The photomultiplier tube is also modified to suppress and correct gain fluctuation of the photomultiplier. The DSP system has been installed in the center channel of the vertical neutron collimator system in JT‐60U and applied to measurements of n...

The μ-particle rare decay physics experiment, the MU-E-GAMMA (MEG) experiment, will soon be operational at the Paul Scherrer Institute in Zurich. To achieve the extremely high sensitivity required to detect gamma rays, 800 L of liquid xenon is used as the medium in the calorimeter, viewed by 830 photomultiplier tubes (PMT) immersed in it. The required liquid xenon purity is of the order of ppb of water, and is obtained by using a cryogenic centrifugal pump and cold molecular sieves. The heat load of the calorimeter at 165 K is to be approximately 120 W, which is removed by a pulse-tube cryocooler developed at KEK and built by Iwatani Industrial Gas Corp., with a cooling power of about 200 W at 165 K. The cryogenic system is also equipped with a 1000-L dewar. This paper describes the results of an initial performance test of each cryogenic component.

To investigate the deuteron and triton density ratio in core plasmas, a new methodology with measurement of tritium (DT) and deuterium (DD) neutron count rate ratio using a double‐crystal time‐of‐flight (TOF) spectrometer is proposed. Multi‐discriminator electronic circuits for the first and second detectors are used in addition to the TOF technique. The optimum arrangement of the detectors and discrimination window were examined considering the relations between the geometrical arrangement and deposited energy using a Monte Carlo Code, PHITS (Particle and Heavy Ion Transport Code System). An experiment to verify the calculations was performed using DD neutrons from an accelerator.

Recent lower hybrid current drive (LHCD), and heating (LHH) experiments on JT-60 are reported. The current drive product of neRpIRF approximately 12.5*1019 m-2 MA was achieved at the LH power of approximately 4.5 MW, and the CD efficiency, the energy confinement, the global power balance and the heat load on divertor plates were investigated in high power LHCD plasmas. Nearly steady state H-mode discharges were found during LHCD with two different frequency injections. Sawtooth suppression in NB heated plasmas by LHCD have shown an improvement in confinement near the plasma center. Parametric instabilities in LH heating experiments were significantly reduced by increasing the plasma current, and the stored energy increased linearly with heating power of up to approximately 9 MW at ne approximately 7*1019 m-3 and Ip=2.75 MA. Parametric instabilities near the plasma edge in the ion heating regime were also reduced in peaked density plasmas produced by pellet injection and LH waves increased the central plasma pressure at ne(0) > 1.4*1020 m-3.

Applications of the digital signal processing of video signals in broadcasting, communication, and consumer electronics are reviewed. These include: digital encoding systems, digital video effect equipment, and the television standards converter for broadcasting; videoconferencing and video telephone equipment; and TV receivers, including those for extended definition and high-definition television (EDTV and HDTV). Performance requirements for video signal processing (VSP) are discussed, and an example of a video signal processor comprising a parallel processor system composed of multiple VSP modules is examined. Future trends in VSP are predicted. >

A high‐power coaxial pulse tube cryocooler, originally developed in KEK and technology‐transferred to Iwatani Industrial Gases Corp (IIGC), has been installed in a large liquid xenon calorimeter to evaluate liquid nitrogen‐free (LN2‐free) operation of the rare μ‐particle decay experiment (MEG). Features of this pulse tube cryocooler include the cold‐end heat exchanger, designed with sufficient surface area to ensure high‐power cooling, and a cylindrical regenerator placed inside the pulse tube giving compact design and ease of fabrication. This production‐level cryocooler provides a cooling power of ∼200 W at 165 K, using a 6 kW Gifford‐McMahon (GM)‐type compressor. The paper describes the detailed configuration of the cryocooler, and the results of the continuous LN2‐free operation of the large prototype liquid xenon calorimeter, which ran for more than 40 days without problems.

An LSI ADPCM codec, which is based on the CCITT standard 32 kbps algorithm, has been developed. The LSI chip has been designed as a software controllable signal processor whose architecture is optimized for the CCITT algorithm. A reconfigurable pipeline multiplier-normalizer-accumulator circuit is effectively utilized for realizing complex ADPCM specifications. The LSI chip, implemented by 2.5 µ CMOS technology, dissipates only 90 milliwatts of power.

A high-power and high-temperature pulse tube cryocooler has been developed for xenon liquefaction and re-condensation for high-energy particle detectors. To meet a cooling power requirement of around 70 W at 165 K, KEK and Nihon University have developed a co-axial pulse tube cryocooler with a configuration of inside regenerator.

SUMMARY Progress of recent digital signal processors for Personal Digital Advisor (PDA) as well as cell phones will soon overrun the requirements of today's applications. With these residual processing capabilities, we should introduce more useful applications. One of such applications is to make a PDA an adviser: from Personal Digital Assistance to Personal Digital Adviser which tells you what you do not understand or recognize, by introducing novel recognition schemes. The schemes belong to a class of modifying registered images, where the matching process is carried out between an input image and a set of regenerated images from registered DB. Although these approaches greatly improve performance, the regeneration of images in real time requires TOPS processing. Judging from our experience, however, such a consumer LSI device may appear within this decade. This talk explains these issues in more detail.

The subsequent creep behaviour of polymers is influenced by prior plastic deformation. The constitutive creep equation is deduced by introducing the concept of a back stress. The creep relation obtained with back stress is compared with the experimental results for the subsequent creep after prior plastic tension. This creep relation gives good agreement with the experimental results for the small creep strain.

This paper presents recent advances in MPEG-2/4 audio and video (AV) codec implementations for broadband and mobile applications. Several design approaches based on special purpose hardwired LSIs, programmable DSPs, media processors, embedded MPUs, and MPUs for personal computers (PCs), which are used to implement MPEG engines are introduced. Then, design approaches for low power and low cost AV codec LSIs for broadband and mobile applications are discussed, by introducing recent implementation examples. Finally, future trends and challenges are discussed.