[en] This issue is the collection of the paper presented at the title meeting. The 13 of the presented papers are indexed individually. (J.P.N.)

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[en] In order to investigate the resonant behavior in the parallel network for the fast cycling synchrotron power supply, a theoretical model is introduced by assuming that a train of half-sinusoidal input current pulses is given to the magnet circuit through a choke transformer from a pulse power supply which only feeds the power lost in the network at every operation cycle. The same method can be applied to the distributed multi-mesh network. (author)

[en] In order to verify presence of neutrino oscillation at present, the K2K experiment is carried out. The K2K is an abbreviation of 'KEK to Kamiokande', where KEK is a place forming neutrino and Kamiokande is an elementary particle observation apparatus with 40 m in diameter, 42 m in height, and 50,000 ton of pure water, and situated at 1,000 m in depth of the old Kamioka mine in Gifu prefecture. For formation of neutrino, proton beam by 12 GeV accelerator at KEK was used. The proton beam passed through 400 m of neutrino beam line, and was charged into a target in a horn situated at it downstream to form particle and pi meson constituting origin of neutrino formation. The pulse source was flown 250 kA of pulse current into a horn electromagnet synchronously with taking out of proton beam from an accelerator (two seconds in period) in order to focus pi meson to a direction of the Kamiokande. Here were reported on design to operation results on the apparatus comprising of capacitor, high voltage capacitor, thyristor switch, and pulse transformer. (G.K.)

[en] When measuring a magnetic field of each electromagnet under its acceleration by using back-leg coil of a proton accelerator (PS) main ring bending electromagnet for a sensor, nevertheless total bending electromagnet is connected in series, forming field of each electromagnet was not equal in its details. Here were reported on following three phenomena elucidated on these causes: because of presence of dummy electromagnet and unbalance in capacity of common mode capacitor, two series of electromagnets became asymmetric in load and had a difference in electromagnet magnetic field of both series just after beginning of acceleration due to specific frequency; too late rising-up on magnetic field under acceleration of only two sets of electromagnets of 2-1B' and 3-1B' with different vacuum duct; and, by total renewal of the source and the wiring except gamma(sub T) electromagnet, field induction was reduced but each electromagnet had some differences and only bending electromagnets at both sides of the gamma(sub T) electromagnet suffered interference except one. (G.K.)

[en] Technical development in displacing thyratron switch used conventionally for pulse power supply for high power Klystron to semiconductor switch has been attempted. Now, by using SI-thyristor for a semiconductor device, some evaluation tests on high speed turn-on features of the device with low inductance circuit were carried out. And, by trial production of 45 kV semiconductor switch connected fifteen elements of this device in series, high power evaluation tests were conducted. As a result, it was found that the SI-thyristor had extremely superior turn-on features by a device evaluation test using low inductance circuit, and it was also verified that 45 kV semiconductor switch connected fifteen elements in series had switching capacity sufficient to match with high power thyratron by testing under actual Klystron pulse power supply. (G.K.)

[en] Recently, together with remarkable advancement in features of power semiconductor element and development of control elements such as micro-computer, the source apparatus used in the industrial field is transferring from conventional type one using SCR to switch-mode type one using high speed switch element such as IGBT, MOSFET, and do forth. On the other hand, for specification on electromagnet power supply apparatus used for the particle accelerator, it is also required not only to secure electrical properties such as conventional performance prospect type, high precision, high speed response, and so forth, but also to adopt for miniaturization, economicalization and environment as well as normality in industrial field. Here was introduced on progress and results of high performance power supply with high functionality for synchrotron accelerator developed by the IDX Tokyo Denshi Co., Ltd. (G.K.)

[en] In 12 GeV proton synchrotron in the High Energy Accelerator Research Organization, proton beam incident into main ring with 500 MeV of energy in accelerated to 12 GeV to lead to a physical laboratory after pulling out from the ring. At a process of acceleration in the main ring, a phenomenon shifting stable acceleration region of RF phase against beam occurs. The region occurring this phenomenon is called phase transition region. When passing through this region, proton beam loses beam with high density, especially affects a definite effect to its accelerating efficiency. As a method of preventing this effect, a method to shorten the time passing through near the transition region as possible is well known. This can be carried out by using a tetrapole electromagnet mounted in the ring. For this purpose, two sets of pulse waveform forming source to pulse excite a tetrapole electromagnet mounted at the main ring and a control board to intend for cooperative operation of these two sets of sources were developed, by using which some experimental results satisfying various conditions were obtained

[en] It was found on April, 1999 that as beam of the KEKB accelerator oscillates under a time cycle, a stable beam collision could not be carried out. However, observed beam oscillation was remarkable in vertical direction of positron ring but was not so large in horizontal direction of both beams and in vertical direction of electron ring. By analysis of logging data and so forth of the KEKB accelerator it was found that frequency of the oscillation was about 0.5 Hz similar to pattern frequency of the PS accelerator and that it formed only when operating with PS main ring. As mechanism receiving power near the beam collision point was unknown yet, it was found that it was due to leakage magnetic field from source cable for electromagnet and preliminary electromagnet for monitoring of PS main ring to receive power under M5 source room. Effect of these magnetic fields was 280 mG-m in integral value of the field, and 2.4 micro-rad in kick angle. As magnitude of the beam oscillation at collision point was about 1 to 1.2 micron (peak to peak) at the first observation, it reduced to about its half after rolling into a Belle detector and was controlled further to 1/3 to 1/4 by countermeasure around the M5 room. (G.K.)