| Paper | Title | Page |
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| MOPP108 | Vertical Electro-Polishing of Nb Nine-Cell Cavity Using Cathode with Variable-Geometry Wings | 307 |
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| Marui Galvanizing Co. Ltd. has been studying on Vertical Electro-Polishing (VEP) of Nb superconducting accelerator cavity for the mass-production and cost-reduction of Electro-Polishing (EP) process in collaboration with KEK. And we invented VEP process by a cathode with variable-geometry wings to get uniform distributions of both electric current and EP solution flow. Using this cathode, we performed various tests of VEP with Nb single-cell cavities. In this article, we will report fabrication of the first VEP facility for Nb nine-cell cavity and the VEP results using cathode with variable-geometry wings. | ||
TUPP074 |
Study on Fabrication of Superconducting RF 9-cell Cavity for ILC at KEK. | |
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| We had constructed the Cavity Fabrication Facility (CFF) for the fabrication of superconducting RF cavity at KEK from 2009 to 2011. In the facility, we installed a deep-drawing machine, a half-cup trimming machine, an electron-beam welding machine, and a chemical etching room in one place. We started the study on the fabrication of 9-cell cavity for International Linear Collier (ILC) from 2009 using this facility. The study is focusing on the cost reduction with keeping high performance of cavity, and the goal is the establishment of mass-production procedure for ILC. We finished the fabrication of two 9-cell cavities by using tools, machines, and equipment of this facility. This article reports the current status of the studies on fabrication of cavity, including the results of vertical tests for the 9-cell cavities which were fabricated in this facillity. | ||
| TUPP101 | Vertical Electro-Polishing of Nb Single-Cell Cavity Using Cathode with Variable-Geometry Wings and Its Results of Vertical Test | 662 |
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| Marui Galvanizing Co. Ltd. has been studying Vertical Electro-Polishing (VEP) on Nb superconducting accelerator cavity with the goal of mass-production and cost-reduction of Electro-Polishing (EP) process in collaboration with KEK and CEA Saclay. And we invented variable-geometry wings cathode for VEP process to get uniform distributions of both electric current and EP solution flow. Using this cathode, we performed various tests of VEP with Nb single-cell cavities. In this article, we will report the results of vertical test of Nb single-cell cavity which is VEP’ed by cathode with variable-geometry wings. | ||
| THPP075 | Development of Superconducting Spoke Cavity for Electron Accelerators | 1030 |
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Funding: This work was supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan. We have launched a development program of a superconducting spoke cavity for electron acceleration, in order to realize a compact industrial-use X-ray source with the laser-Compton scattering. Efforts for optimizing a cavity design by the electromagnetic field simulation, tracking of multipactor electrons and mechanical property calculations have been continued so far. The optimization processes reached the final stage, and studies toward fabrication processes started. In this presentation, we will show results and processes of the optimization. Attempts to fabricate the spoke cavity, which have just begun, will also be presented. |
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| THPP098 | Vertical Electropolishing of Nb Coupon Cavity and Surface Study of the Coupon Samples | 1080 |
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| We have been carrying out vertical electropolishing (VEP) of 1.3 GHz Nb cavities for the ILC for 2 years. In this article we present VEP of a single cell Nb coupon cavity containing 6 Nb disk type coupons located at beam pipes, irises and equator positions of the cavity. VEP experiments were performed using our special ninja-cathode newly developed and a straight rod cathode in order to observe and compare the homogeneity of electropolishing (EP) and surface quality on the entire surface of the single cell cavity. EP current was measured for the individual coupons under different EP conditions in order to study the EP phenomenon on the different positions of the cavity. The surfaces of the coupons were analyzed by x-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDX). This article describes VEP and surface analysis results in detail. | ||
| THPP107 | Study on Polishing Method of Nb Surface by Periodic Reverse Current Electrolysis With Alkali Solution | 1102 |
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| Currently, electropolising method is thought to be the best method for the final surface preparation of superconducting RF cavity to obtain high gradient. In this conventional electropolising method, the electrolyte is the mixture of fluoric and sulfuric acids. Therefore, the operation of this method is dangerous, and the equipment becomes expensive because all parts should be made of high density polyethylene or fluorocarbon resin to avoid metallic parts which suffers from corrosion by electrolyte. Moreover, sulfur is produced as byproduct in the electropolishing process and this causes degradation of cavity performance. In order to overcome these drawbacks, we studied new polishing method of Nb surface by periodic reverse current electrolysis with alkali solution which causes no sulfur and allows the usage of metallic parts to realize cost effective equipment. In the study, we performed experiment of Nb coupons by this new method and obtained as good surface roughness as conventional electropolishing method. In this article, we report the details of the study. | ||