| Paper | Title | Page |
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| MOPRO001 | Upgrade Status of Injector LINAC for SuperKEKB | 59 |
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| The SuperKEKB collider is under construction to achieve 40-times higher luminosity than that of previous KEKB collider. The injector LINAC should provide high-intensity and low-emittance beams of 7-GeV electron and 4-GeV positron for SuperKEKB based on a nano-beam scheme. A photocathode RF-gun for low emittance electron beam has been already installed and the commissioning has started. The construction of positron capture section using a flux-concentrator and the dumping ring for low emittance positron beam is in progress. The simultaneous top-up injections to four storage-rings including photon factories is also required. In the upstream of dumping ring, the compatible optics between positron and electron has been designed. In the downstream of dumping ring, RF phase, focusing, and steering magnets will be switched by pulse to pulse against each beam-mode for optimising beam-transportation. This paper describes recent upgrade status toward the SuperKEKB. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO001 | |
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| MOPRI003 | Positron Yield Optimization by Adjusting the Components Offset and Orientation | 576 |
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| In order to keep high luminosity beam collision condition at SuperKEKB, low emittance electron/positron injection and flexible pulse-to-pulse switching of these beam modes are essential requirements. While a primary electron beam strikes on a target to generate positrons, an injection electron beam passes through a small hole besides the target. Since the injection electron orbit should be on axis to avoid emittance growth, the target and the flux concentrator for positron focusing have a few millimeters offset from the axis. This offset positron generation gives significant degradation in the positron yield. In this paper, we will discuss positron yield improvement by proper orientation of the cut-in slit of the flux concentrator which yields un-symmetric field distribution and primary electron incident point. With particle tracking simulation taking three dimensional field distribution into account, an ideal positron trajectory giving optimum yield was found. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI003 | |
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| MOPRI004 | SuperKEKB Positron Source Construction Status | 579 |
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| The KEKB positron source is under the upgrade for SuperKEKB. The previous positron production target and capture section have been removed and the new system is constructed at a location forty meters upstream to have sufficient energy margin for beam injection to the newly introduced damping ring. A flux concentrator is introduced in the new capture section to make an adiabatic matching system. Large aperture (30mm in diameter) S-band accelerating structures are introduced in the capture section and in the subsequent accelerator module to enlarge the transverse phase space acceptance. The beam focusing system of quadrupoles is also upgraded for a comparable beam acceptance to that of the capture section. This paper reports on the status of the SuperKEKB positron source construction and the preliminary positron beam commissioning. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI004 | |
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| TUPRI109 | Construction and Commissioning of Event Timing System at SuperKEKB | 1829 |
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The Event Timing System of Injector Linac at KEK is upgraded to satisfy the new requirements for the SuperKEKB project. After finishing the design and feasibility studies*, we have constructed the new system at Main Trigger Station of Linac. The new functions are developed in this system to perform the injection control of positrons with the newly constructed damping ring. Besides, we integrate the capability to adjust the trigger timing just 20 ms before injection so that the injection RF-bucket of the ring can be decided at the last minute. Now, both the new system and the current working system are operational at Main Trigger Station. This is important for the smooth taking over of Event Timing System. Even during the construction period, Linac must be operated to provide beams into the two light source rings. In this situation, we can carry out enough tests with the actual condition. These tests do not disturb the regular operation and brush up the Event Timing System to enable the quick startup of the SuperKEKB operation. We report about the detailed configuration of the new system and its commissioning performed in the 2014 spring run period.
* H. Kaji et al., "Upgrade of Event Timing System at SuperKEKB", proceedings of ICALEPCS13, San Francisco, USA, October 6-11, 2013. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI109 | |
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| THPRO109 | Design and Status of the SuperKEKB Accelerator Control Network System | 3150 |
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| We have upgraded the accelerator control network system for SuperKEKB, the upgrade of the KEKB asymmetric energy e+e− collider for the next generation B-factory experiment in Japan. For SuperKEKB, the accelerator control network system with the higher performance of the wider bandwidth data transfer, and more reliable and redundant configuration, is required, to ensure the robust operations under the 40 times higher luminosity. We install the 10 gigabit Ethernet (10GbE) network switches for the wider network bandwidth and optical cables to construct the redundant network. We reconfigure the network design to connect the accelerator control network and the KEK laboratory network to enhance the security. For the beamline construction and the accelerator components maintenance, we install the new wireless network system consists with the Leaky Coaxial (LCX) cable antennas and collinear antennas, which have good radiation hardness of >1MGy, into the 3 km circumference accelerator tunnel. In this paper, we describe the design and current status of the SuperKEKB accelerator control network system. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO109 | |
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