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A new technology to make the bipolar kicker magnet system, using a symmetric Blumlein Pulse Forming Network (SBPFN) system is introduced. In the 50 GeV, the fast extraction system is designed to deliver the 50 GeV beam to the downstream neutrino oscillation experiment beam line with the Super-Kamiokande detector.

We report a novel scheme for fast ion bunch compression by barrier pulse control in an induction synchrotron in which an effective acceleration voltage pulse with a pseudo-linear slope is generated by temporal handling of rectangular induction acceleration pulses. With beam handling, a head-to-tail momentum gradient is yielded to the beam in a desired manner and the beam is gradually compressed over 30 turns. In the proof-of-principle experiment, which used a 75 μA He1+ beam at 50 keV per nucleon, the root mean square bunch length was reduced to 0.44 μs by a factor of 3.5 in 30 turns with no appreciable beam loss due to the beam compression scheme. This scheme is useful for various beam applications including ion beam heating. [ABSTRACT FROM AUTHOR]

The normalized elimination of the small component (NESC) theory, recently proposed by Filatov and Cremer [J. Chem. Phys. 122, 064104 (2005)], is extended to include magnetic interactions and applied to the calculation of the nuclear magnetic shielding in HX (X=F,Cl,Br,I) systems. The NESC calculations are performed at the levels of the zeroth-order regular approximation (ZORA) and the second-order regular approximation (SORA). The calculations show that the NESC-ZORA results are very close to the NESC-SORA results, except for the shielding of the I nucleus. Both the NESC-ZORA and NESC-SORA calculations yield very similar results to the previously reported values obtained using the relativistic infinite-order two-component coupled Hartree-Fock method. The difference between NESC-ZORA and NESC-SORA results is significant for the shieldings of iodine. [ABSTRACT FROM AUTHOR]

Voltage shift phenomena of the hysteresis loop were characterized for a c-axis oriented heteroepitaxial BaTiO[sub 3] film by means of switching current measurements using various types of pulse sequences. During application of voltage, the hysteresis loop gradually shifted along the voltage axis according to the polarity of the voltage. Even after the application of voltage, while the top and bottom electrodes were short-circuited, the hysteresis loop continued to move. Under certain conditions, a part of the hysteresis loop shifted back, whereas the rest shifted forward. These results were explained, assuming that there is a nonswitching layer between the ferroelectric layer and the bottom electrode, and that the discontinuity of polarization can be compensated by injection of negative charges from the electrode. It was suggested that the nonswitching layer is possibly formed by relaxation of lattice misfit strain in the heteroepitaxial ferroelectric thin film. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Discusses a study on infrared absorption, electron paramagnetic resonance (EPR) spectra and electrical resistivity of semi-insulating liquid encapsulated gallium-phosphorus crystals irradiated by fast neutrons. Decrease of electrical resistivity with neuron irradiation; Comparison of resistivity data of gallium-phosphorus with gallium arsenide; Analysis of the EPR spectrum.

Details a study which examined the influence of photoexcitation on the hopping conduction in neutron transmutation doping gallium arsenide (GaAs). Discussion of the neutron transmutation doping of GaAs; Measurement of photoconductance; Temperature dependence of photoconductance.

Voltage shift phenomena of the synthesis loop were characterized for a c-axis orientated heteroepitaxial BaTiO3 film by means of switching current measurements using various types of pulse sequences. The voltage shift was gradual when the shift was plotted as a function of a logarithmic scale of the pulse length.

Deals with a study which examined the annealing behavior of photoconductance in semi-insulating gallium arsenide crystals in terms of the electron-irradiation-induced defects. Techniques used in studying point defects; Information on the materials; Peak of photoluminescence emissions.

Presents a study that reported a preliminary evaluation of the uniformity of electrical properties in neutron transmutation doping (NTD) semi-insulating gallium arsenide (GaAs) after annealing. Description of NTD; Limitations of low-level NTD in semi-insulating GaAs; Difference between the resistivities for the samples irradiated at different correlates and the amount of activated impurities in each sample.

Four microseconds long Ar3+ beam with injection energy of 15 keV/u has been injected into the Digital Accelerator of the High-Energy Accelerator Research Organization. Beam production, transportation, and injection are described as well as machine properties. Results of a free running experiment under static magnetic field and longitudinal confinement and acceleration under a fast ramping magnetic field are presented in detail with a brief discussion on the beam lifetime. [ABSTRACT FROM PUBLISHER]

The injection system of the 3-GeV RCS (Rapid Cycling Synchrotron) in J-PARC (Japan Proton Accelerator Research Complex) consists of four main orbit bump magnets (shift bump) to merge the injection beam with the circulating beam. In order to control the injection beam with sufficient accuracy, the shift bump magnets need a wide uniform magnetic field. The magnetic field design and the structural analysis of the shift bump magnets have been performed using three-dimensional electromagnetic and mechanical analysis codes. The shift bump magnets have realized a uniform field with less than 0.35% inhomogeneity over a wider area, which is 400 mm in width and 240 mm in height. Furthermore, the magnets operate with a high magnetic field and they are located in high radioactive level area. The flexible bar is applied to the coil as the countermeasure for thermal expansion and the insulator has strong radiation resistance. [ABSTRACT FROM AUTHOR]

The injection bump system of the 3-GeV RCS (Rapid Cycling Synchrotron) in J-PARC (Japan Proton Accelerator Research Complex) consists of the pulse bending magnets for the injection bump orbit, which are four horizontal bending magnets (shift bump), four horizontal painting magnets (h-paint bump) and two vertical painting magnets (v-paint bump). The shift bump magnets, which are connected in series in order to form a closed bump orbit. The injection bump system needs the power supplies with the high speed and flexible current pattern. Furthermore, the tracking error is required less than 1.0% for 1.0 μs pulse current. The power supplies with the IGBT (Insulated Gate Bipolar Transistor) chopper units, which are controlled by the switching frequency over 60 kHz, realize its performance. The decay time of the shift bump power supply is less than 200 microseconds. [ABSTRACT FROM AUTHOR]

Septum magnets are used in the injection and extraction section of the 3 GeV rapid cycling synchrotron (RCS) of J-PARC (Japan Proton Accelerator Research Complex). The RCS needs seven septum magnets, two for the injection line, two for the beam dump line and three for the extraction line, respectively. These septa require a large aperture for low-loss operation with high intensity beams, and high durability for minimizing maintenance after high activation. For insuring mechanical stability the septum magnets have been designed to work DC. The septa magnets work outside a vacuum, thus eliminating any trouble due to the leakage of cooling water into the vacuum system. We have been designing them by using the three dimensional magnet static field calculation code, TOSCA. This paper describes the flatness of the magnetic field in the gap and reduction of the leakage field of the septum magnets in the RCS. [ABSTRACT FROM AUTHOR]

Kicker magnets are installed in the extraction section of the RCS (Rapid Cycling Synchrotron) in J-PARC (Japan Proton Accelerator Research Complex) facility. They extract a 3 GeV proton beam and inject it into a downstream beam transport line at a repetition rate of 25 Hz. The power supply is mainly composed of the charging unit, the pulse forming network, and thyratrons as switching device. The maximum charging voltage is 80 kV. The kicker magnet is a distributed (transmission line) twin-C type. The circuit parameters are designed to have the 10 characteristic impedance. The magnets are installed in vacuum chambers to prevent voltage breakdown. In order to accept 1 MW beam power, strict conditions are imposed on the kicker system. In the first part of this paper, we give an outline of the RCS extraction kicker system. Next, we report the specifications and performance of the power source and magnet. In addition, we report the measurements of the vacuum performance and magnetic field. [ABSTRACT FROM AUTHOR]