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| MOPMF073 | Rejuvenation of 7-Gev SuperKEKB Injector Linac | 300 |
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| KEK injector linac has delivered electrons and positrons for particle physics and photon science experiments for more than 30 years. It was upgraded for the SuperKEKB project, which aims at a 40-fold increase in luminosity over the previous project KEKB, in order to increase our understanding of flavor physics beyond the standard model of elementary particle physics. SuperKEKB energy-asymmetric electron-positron collider with its extremely high luminosity requires a high current, low emittance and low energy spread injection beam from the injector. The electron beam is generated by a new type of RF gun, that provides a much higher beam current to correspond to a large stored beam current and a short lifetime in the ring. The positron source is another major challenge that enhances the positron bunch intensity from 1 to 4 nC by increasing the positron capture efficiency, and the positron beam emittance is reduced from 2000 μm to 10 μm in the vertical plane by introducing a damping ring, followed by the bunch compressor and energy compressor. The summary of the rejuvenation is reported. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF073 | |
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| MOPMF074 | Beam Phase Space Jitter and Effective Emittance for SuperKEKB Injector Linac | 304 |
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| In SuperKEKB linac, stable high charged low emittance beam is necessary. Transported beam to SuperKEKB Main Ring (MR) must be stable to the extent that the beam can be injected inside MR acceptance. SuperKEKB requirement must be satisfied for emittance including beam phase space jitter, called as effective emittance. Large amplitude beam position jitter has been measured at linac end. We evaluated that the effect of the beam position jitter on effective emittance and investigated the source of the beam phase space jitter. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF074 | |
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| MOPMF077 | A Design Study of the Electron-driven ILC Positron Source Including Beam Loading Effect | 311 |
| SUSPF003 | use link to see paper's listing under its alternate paper code | |
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| The International Linear Collider (ILC) is a next-generation accelerator for high-energy physics to study the Higgs and top sector in the Standard Model, and new physics such as supersymmetry and dark matter. ILC positron source based on Electron-driven method has been proposed as a reliable technical backup. In this article, we report the design study of the positron source based on the off-the-shelf RF components. The positron is generated and accelerated in a multi-bunch format. To compensate the energy variation by the transient beam loading effect, we employ AM (Amplitude Modulation) technique and the results were 16.60 ± 0.14 MV (peak-to-peak) for L-band 2m cavity driven by 22.5 MW power and 25.76 ± 0.19 MV (peak-to-peak) for S-band 2m ac-celerator driven by 36 MW power with 0.78 A beam load-ing. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF077 | |
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| WEPAK014 | A New Pulse Magnet Control System in the KEK Electron Positron LINAC | 2121 |
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| In 2017, sixty-four pules magnets were installed in the KEK e+/e− LINAC for simultaneous injection to four different rings. Since each ring requires different injection energy, magnetic field in the LINAC has to be changed shot by shot (every 20 ms) according to the destination of the beam. To realize such operation, a PXI express based new control system was installed. Each unit, which consists of an event receiver board, a DAC board, and a ADC board, can set and monitor output current up to 8 pulsed power supply in 16 bit resolution. The timing and control system are integrated in that of the LINAC by using Micro-Research Finland's PXI event receiver board. In terms of software, Windows 8.1 and LabVIEW 2016 were mainly adopted to control the hardware. EPICS channel access (CA) protocol was used to communicate with operator's interface panels. In addition to real-time monitoring by EPICS CA and logging by CSS archiver every 10 s, data are logged every shot (every 20 ms) in the text file together with timestamp, shot ID and destination. At present, thirteen units are stably in operation to control 64 magnets. Further installation of the system is planned in 2018. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAK014 | |
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| WEPAK015 | Beam Gate Control System for SuperKEKB | 2124 |
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The electron beam pulses of injector linac for the SuperKEKB collider are enabled and disabled by Beam Gate control system. This system controls the delivery of triggers to the electron guns at the injector. Also, the septum and kicker magnets for injection point of main ring are controlled with this Beam Gate to avoid unnecessary operation and to prolong their lifetime. The Beam Gate synchronizes the enabling and disabling operations of these hardware even though they are about 1km distant. Besides, from the phase-2 operation, the kicker and septum magnets for newly constructed damping ring becomes controlled apparatus of this system. We develop the new Beam Gate control system with the Event Timing System network*. The new system improves the unsatisfied performance of Beam Gate in the phase-1 operation and realizes the complicated control for phase-2. The advantages of new system are: the control signal is delivered via Event nettork, so that we do not need to cable new network. The enabling and disabling operations for distant hardware are surely synchronized by the Event Timing System.
* H. Kaji et al., "Construction and Commissioning Event Timing System at SuperKEKB", Proceedings of IPAC14, Dresden, Germany (2014). |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAK015 | |
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| THPMF045 | Synchronized Beam Position Measurement for SuperKEKB Injector Linac | 4159 |
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| Toward SuperKEKB project, the injector linac upgrade is ongoing for aiming at the stable beam operation with low emittance and high intensity bunch charge. One of the key challenges is a low emittance preservation of electron beam because the vertical emittance of 20 mm.mrad or less should be transported to the main ring without a damping ring. For this purpose, the fine alignment of accelerator components is a crucial issue since the linac alignment was badly damaged by the big earthquake in 2011. From the simulation results of emittance growth, the alignment of the quadrupole magnets and accelerating structures should be conducted at the level of 300 um in rms along the 600-m-long linac. In addition, we are aiming at the level of 100 um alignment in rms within the short range distance of 100 m long. Even after the fine component alignment can be achieved, the fine beam orbit manipulation is necessary for low emittance preservation. For these reasons, we have developed the new BPM readout system based on VME64x. The new system has improved the precision of beam position measurement up to 3 um from 25 um. We will describe the software development of the new BPM readout system. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF045 | |
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