| Paper | Title | Page |
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| MOPD005 | Recent Activities in ILC R&D at Hitachi | 457 |
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| We participated in the construction of STF (Superconducting RF Test Facility) cryomodule. This paper describes our recent activities in ILC R&D. | ||
| MOPP029 | The First Measurement of Low-loss 9-cell Cavity in a Cryomodule at STF | 610 |
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| We are constructing Superconducting RF Test Facility (STF) at KEK for the R&D of International Linear Collider (ILC) accelerator. In the beginning of year 2008, we installed one high-gradient Low-Loss (LL) type 9-cell cavity into a cryomodule at STF, where we assembled an input coupler and peripherals with the cavity in a clean room, and the assembled cavity packages were dressed with thermal shields and installed into a cryomodule. At the room-temperature, we performed the processing of capacitive-coupling input-coupler upto the RF power of 250 kW. At the temperature of 4 K, we measured the loaded Q of the cavity and the tuner was tested. At the temperature of 2 K, high-power RF was supplied from a klystron to the cavity and the performance of the cavity packeage was tested. This article presents the results of the first test of the Low-Loss (LL) 9-cell cavity package at 2 K in a cryomodule. | ||
| MOPP083 | Status of High Power Tests of Normal Conducting Single-cell Structures | 742 |
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We report results of ongoing high power tests of single cell traveling wave and standing wave structures. These tests are part of an experimental and theoretical study of rf breakdown in normal conducting structures at 11.4 GHz*. The goal of this study is to determine the gradient potential of normal-conducting, rf powered particle beam accelerators. The test setup consists of reusable mode launchers and short test structures and powered by SLAC’s XL-4 klystron. The mode launchers and structures were manufactured at SLAC and KEK and tested in SLAC klystron test laboratory.
*V. A. Dolgashev, S. G. Tantawi, et al. “High Power Tests of Normal Conducting Single Cell Structures,” SLAC-PUB-12956, PAC07, Albuquerque, New Mexico, 25-29 June 2007, pp 2430-2432. |
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| MOPP144 | The First Cool-down Tests of the 6 Meter-Long-Cryomodules for Superconducting RF Test Facility (STF) at KEK | 892 |
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| KEK is presently constructing the Superconducting RF Test Facility (STF) as the center of the ILC-R&D in Asia from 2005. In this project, KEK aims to get the manufacturing and operational experiences of the RF cavity and cryomodule toward the ILC, and two cryomodules have been developed. These cryomodules are 6 meter long and have 4 nine-cell cavities in each cryostat. The basic cross section designs of the cryomodules are almost same as the design of TESLA type-III, however, each cryostat has the different type of cavities, TESLA type and Low-Loss type. The tests for the cryomodules are planed to be performed at three steps. In the first test, measurements of the cryogenic performances of these cryomodules are the main objective. One nine-cell cavity was assembled in each cryostat and the cool-down of the two cryomodules was performed. In the following tests, the four nine-cell cavities will be assembled in each cryostat as the complete integration and the beam test will be performed. In this paper, we will report the design of the cryomodules and the cryogenic performances at the first cold test. | ||
| TUPP156 | Development of a Compact X-ray Source Based on Laser-Compton Scattering with a Pulsed-laser Super-cavity | 1872 |
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| A compact and high quality x-ray source is required for various fields, such as medical diagnosis, drug manifacturing and biological sciences. Laser-Compton based x-ray source that consists of a compact electron storage ring and a pulsed-laser super-cavity is one of the solutions of a compact x-ray source. Pulsed-laser super-cavity has been developed at KEK-ATF for a compact high brightness x-ray source. The pulsed-laser super-cavity enables to make high peak power and small waist laser at the collision point with the electron beam. Recently, 357MHz mode-locked Nd:VAN laser pulses can be stacked stably in a 420mm long Fabry-Perot cavity with 2.5kW average power in our R&D. On the other hand, we have succeeded to stack the pulsed amplified laser in the super-cavity. This indicates that the number of X-ray is multiplied due to the gain in the amplification system to synchronize the pulsed pump to the beam. In view of this successful result, we have started an X-ray generation experiment using a super-cavity and a multi-bunch electron beam at KEK-LUCX. Development of the super-cavity and the results of X-ray generation experiment will be presented at the conference. | ||
| WEPP084 | Fabrication of a Quadrant-type Accelerator Structure for CLIC | 2716 |
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| In order to heavily damp the higher order modes of an accelerator structure for CLIC, two kind of damping mechanisms are implemented in one of the designs. Here each cell is equipped with electrically coupled damping channels in addition to the magnetically coupled waveguides. This design requires an assembly of longitudinally cut four quadrants to form a structure and the parts are necessarily made with milling. Since KEK has developed a high-precision machining of X-band accelerator cells with milling and turning at the same time, the experience was extended to the milling of this quadrant. Firstly, the fabrication test of a short quadrant was performed with multiple vendors to taste the present-day engineering level of milling. Following this, a full-size quadrant is also made. In this course, some of the key features are addressed, such as flatness of the reference mating surfaces, alignment grooves, 3D profile shape of the cells, surface roughness and edge treatment. In this paper, these issues are discussed from both fabrication and evaluation point of views. | ||
| WEPP106 | High-gradient Experiments with Narrow Waveguides | 2758 |
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| High-gradient RF breakdown studies are presently being conducted at Nextef. To study the characteristics of different materials on high-field RF breakdown, we have performed experiments by using a reduced cross-sectional waveguide that has a field of approximately 200MV/m at an RF power of 100MW. A description of the high-gradient testing of copper and stainless-steel waveguides is reported. |