| Paper | Title | Page |
|---|---|---|
| TUPMP019 | Vacuum Performance of the NEG-coated Chamber for U#19 at PF-ring | 1276 |
|
||
| At the Photon Factory storage ring (PF-ring) in KEK, a new APPLE-II type elliptically polarizing undulator (U#19) was installed in October 2018. The U#19 vacuum chamber is 4.1 meters in length, and the beam channel with a 15x90 elliptical profile and two cooling-water channels alongside were formed by extrusion of A6060-T6 aluminum alloy. The inner surface of the beam channel is coated with a Ti-Zr-V Non-Evaporable Getter (NEG) thin film, as it has a high effective pumping speed and a low Photon Stimulated Desorption (PSD) yield. After the installation of the U#19, the neighboring uncoated chambers and vacuum components were baked out at 200 °C for 44 hours, and then the NEG coating was activated at 160 °C for 48 hours. As a result, the pressures in the neighboring chambers reached as low as 10-8 Pa. The conditioning of the vacuum chambers with irradiation of Synchrotron radiation evolved favorably as had been expected by a combined simulation of Synrad and Molflow, leading to a satisfactory recovery of the beam lifetime. Vacuum performance of the NEG-coated chamber was assessed especially by means of a residual gas analysis, and the properties of the NEG film were characterized by surface analyses including SEM, EDX, and XRD. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP019 | |
| About • | paper received ※ 16 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUPGW036 | 1 mA Stable Energy Recovery Beam Operation with Small Beam Emittance | 1482 |
|
||
|
A compact energy-recovery linac (cERL) have been operating since 2013 at KEK to develop critical components for ERL facility. Details of design, construction and the result of initial commissioning are already reported*. This paper will describe the details of further improvements and researches to achieve higher averaged beam current of 1 mA with continuous-wave (CW) beam pattern. At first, to keep the small beam emittance produced by 500 kV DC-photocathode gun, tuning of low-energy beam transport is essential. Also, we found some components degrades the beam quality, i.e., a non-metallic mirror which disturbed the beam orbit. Other important aspects are the measurement and mitigation of the beam losses. Combination of beam collimator and tuning of the beam optics can improve the beam halo enough to operate with 1 mA stably. The cERL has been operated with beam energy at 20 MeV or 17.5 MeV and with beam rep-rate of 1300 MHz or 162.5 MHz depending on the purpose of experiments. In each operation, the efficiency of the energy recovery was confirmed to be better than 99.9 %.
* S. Sakanaka, et.al., Nucl. Instr. and Meth. A 877 (2017)197, https://doi.org/10.1016/j.nima.2017.08.051 |
||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW036 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUPGW106 | Present Status of the PF-ring and PF-AR Operations | 1654 |
|
||
| The Photon Factory at KEK has been managing two synchrotron radiation sources, the PF-ring and PF-AR, for over 30 years. Although their operation time has been decreasing in recent years for budget reasons, continuous efforts to improve their performance have been made. In this paper, the operational status of these light sources for FY2018 is described. At the PF-ring, a first-generation undulator was renewed with the beamline components. A vacuum chamber for the new undulator was applied the NEG coating on the inner surface. This is the first attempt in Japanese light sources that the NEG-coated chamber is used for undulators. At the PF-AR, the top-up injection using the direct beam transport line was introduced to the user operation for the first time. Since modification of the beam injector LINAC for enabling simultaneous injection to the four different rings (the PF-ring, PF-AR, SuperKEKB HER and LER) was completed, this top-up operation no longer disturbs the operation of the other three rings. A low-energy operation of the PF-AR was also tested to secure more operation time within the limited budget. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW106 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUPRB035 | Stimulated Emission of THz Coherent Diffraction Radiation in an Optical Cavity by a Multibunch Electron Beam | 1763 |
|
||
|
Funding: JSPS KAKENHI Accelerator-based terahertz (THz) radiation has been expected to realize a high-power broad-band source. Employing a low-emittance and short-bunch electron beam at a high repetition rate, a scheme to resonantly excite optical cavity modes of THz spectrum range via coherent diffraction radiation has been proposed. The confocal cavity design is the special case that resonance conditions of all the eigen modes coincide, resulting in realizing broad-band excitation. But in general cases of non-confocal cavities, the resonance condition depends on the mode, and the resonance peak becomes wide and weak. We performed an experiment with a non-confocal cavity as a follow-up experiment of that we have done with a confocal cavity. The result confirmed that the confocal design is the key for a broad-band source. |
||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB035 | |
| About • | paper received ※ 26 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| THPMP012 | New Industrial Application Beamline for the cERL in KEK | 3475 |
|
||
| The new beam line for the industrial applications is constructed at the cERL (compact Energy Recovery LINAC) in KEK. In these applications, only north straight sections of cERL consisting of injector and main LINAC will be used. The test for the radio isotope production and electron beam irradiation for the materials are firstly planned with very small beam current without energy recovery. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP012 | |
| About • | paper received ※ 11 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| THPTS027 | Accelerator Implementing Development of Ceramics Chamber with Integrated Pulsed Magnet for Beam Test | 4164 |
|
||
|
We advance the development of Ceramics Chamber Integrated Pulsed Magnet (CCIPM) of air-core type as the application to low emittance ring with a narrow bore of light source accelerator in the future. The CCIPM is composed of ceramics cylinder of 60 mm diameter and four copper coils, which are implanted in the groove penetrated on the ceramic thickness along 30 cm length by silver brazing*. In addition to this structure, we succeeded in the implementations of cable connecting base that mechanically connect the coils and power supply with feeder lines and the pattern shape coating inside the ceramic cylinder. Improved brazing technique made it possible to braze the coil and the base on the coil at the same time that the coils are implanted in the ceramic thickness. Newly developed functional coating can reduce the eddy current caused by main magnetic field and pass the alternate component of beam wall current by capacitance structure. We report the details about the performance from the viewpoint of vacuum, magnetic field, insulation on the accelerator implementation with the approach to new technical development, and the preparation progress of beam test in beam-transport line.
* C. Mitsuda, et al., in Proc. IPAC2015, Richmond, VA, USA, p. 2879 |
||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS027 | |
| About • | paper received ※ 12 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |