arXiv subjects

N. Kamikubota

Publications and source records attributed to N. Kamikubota.

5 recordsLinked to original sources

arXiv2002

Beam Feedback Systems and BPM Read-out System for the Two-Bunch Acceleration at Kekb Linac

In order to double the positron injection rate into the KEKB ring, a two-bunch acceleration scheme has been studied at the linac, in which bunches separated by 96 ns are accelerated in 50 Hz. In this scheme the stabilization of energy and orbit of each bunch is indispensable. Thus the beam energy and orbit feedback systems have been upgraded. Since beam characteristics are acquired through beam position monitors (BPM), their read-out system was improved to meet two-bunch requirements. Combined waveforms from BPM's were adjusted with delay cables avoiding overlaps and they enabled simultaneous measurement of beam positions of two bunches. The beam energies of two bunches were balanced by tuning rf pulse timings, and the average energy was stabilized by adjusting the accelerating rf phases. The average beam orbits were also stabilized. Slow feedback systems at the injector section for charge and bunching stabilities are being planned as well. These systems were used successfully in the test beams and will be employed in the routine operation.

physics.acc-ph↗

arXiv2002

Implementation of the Epics Device Support for Network-Based Controllers

In the control system of the JAERI-KEK joint project (High Intensity Proton Accelerator Facility), it is planned to employ network-based controllers such as PLC's and measurement stations instead of using other field control networks, since the network hardware and software can be standardized and they have been successfully utilized in other accelerator control systems in KEK. EPICS software support for those controllers was designed paying special attention to robustness and has been implemented and applied for the accelerator test stand. Basic functionalities were confirmed and miscellaneous functions such as diagnosis of the software itself would be added. Since many kinds of network-based equipment such as oscilloscopes have become available recently, they are considered to be integrated as well. They may enable more manageable controllers.

physics.acc-ph↗

arXiv2001

Introduction of Modern Subsystems at the KEK Injector-linac

As an accelerator control system survives over several years, it is often the case that new subsystems are introduced into the original control system. The control system for the KEK electron/positron injector-linac has been using Unix workstations and VME computers since 1993. During the eight-year operation, we extended the system by introducing a) Windows PCs, b) PLC controllers with a network interface, and c) web servers based on modern information technology. Although such new subsystems are essential to improve control functionalities, they often cause communication problems with the original control system. We discuss the experienced problems, and present our solutions for them.

physics.acc-ph↗

arXiv2001

A Control System of the Joint-Project Accelerator Complex

The current status of the control system for a new high intensity proton accelerator, the JAERI-KEK Joint Project, is presented. The Phase 1 of the Joint-Project has been approved and recently started its construction at JAERI site at Tokai. The first beam commissioning is scheduled in 2006. In parallel with it, a 60-MeV Linac is now being constructed at KEK site at Tsukuba for R&D purpose. Recently the Project has officially decided to use the Experimental Physics and Industrial Control System (EPICS). Under the EPICS environment, we are challenging to implement the Ethernet/IP network for all communication, even at the level of end-point controllers which are so far connected via a field bus. In order to realize such a system, three new controllers (PLCs, WE7000 stations and general-purpose Ethernet boards) are being developed. A prototype EPICS driver for the PLCs works fine and is used to control the ion-source at the KEK Linac.

physics.acc-ph↗

arXiv2000

Beam Switching and Beam Feedback Systems at KEKB Linac

The KEK 8-GeV electron / 3.5-GeV positron linac has been operated with very different beam specifications for downstream rings, KEKB, PF and PF-AR. For the reliable operation among these beam modes intelligent beam switching and beam feedback systems have been developed and used since its commissioning. A software panel is used to choose one of four beam modes and a switching sequence is executed in about two minutes. Most items in a sequence are simple operations followed by failure recoveries. The magnet standardization part consumes most of the time. The sequence can be re-arranged easily by accelerator operators. Linac beam modes are switched about fifty times a day using this software. In order to stabilize linac beam energy and orbits, as well as some accelerator equipment, about thirty software beam feedback loops have been installed. They have been utilized routinely in all beam modes, and have improved its beam quality. Since its software interfaces are standardized, it is easy to add new feedback loops simply defining monitors and actuators.

physics.acc-ph↗