A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z  

Furuya, T.

Paper Title Page
MOOCMH02 Overview of Short Pulse X-ray Generation using Crab Cavities at SPring-8 39
 
  • T. Fujita, H. Hanaki, T. Nakazato
    JASRI/SPring-8, Hyogo-ken
  • K. Akai, K. Ebihara, T. Furuya, K. Hara, T. Honma, K. Hosoyama, A. Kabe, Y. Kojima, S. Mitsunobu, Y. Morita, H. Nakai, K. Nakanishi, M. Ono, Y. Yamamoto
    KEK, Ibaraki
  • M. Matsuoka, K. Sennyu, T. Yanagisawa
    MHI, Tokyo
  • M. Monde
    Mitsubishi Heavy Industries Ltd. (MHI), Takasago
 
 

We have been developing a system to generate a short pulse X-ray using crab cavities at SPring-8 Storage Ring. The ring holds 30-m long straight sections and the vertical beam size at the center of the straight sections is 6.5 micrometers in standard deviation. If we install four superconducting crab cavities and a mini-pole undulator in one of the straight sections, we can convert the time distribution of the electron bunch into the spatial distribution. After slicing the emitted photons with vertical slits, we can obtain a sub-picosecond X-ray pulse. In this scheme, the maximum repetition rate of the short pulse X-ray is the same as the acceleration frequency of the ring (508MHz) and user experiments at other beam-lines are not disturbed by this short pulse generation. We are planning to install KEKB type crab cavities as vertical deflectors. Phase fluctuation among crab cavities must be reduced less than 14 mdeg in order to avoid residual deflection in the vertical direction. In this paper, we report an overview of the short pulse generation scheme and topics of hardware development for stabilization of the RF phase fluctuation.

 

slides icon

Slides

 
MOOCMH03 Beam Commissioning Status of Superconducting Crab Cavities in KEKB 42
 
  • Y. Yamamoto, K. Akai, K. Ebihara, T. Furuya, K. Hara, T. Honma, K. Hosoyama, A. Kabe, Y. Kojima, S. Mitsunobu, Y. Morita, H. Nakai, K. Nakanishi, M. Ono
    KEK, Ibaraki
  • T. Kanekiyo
    Hitachi Technologies and Services Co., Ltd., Kandatsu, Tsuchiura
 
 

Two superconducting crab cavities have been operated stably without any significant trouble for three years in KEKB since Feb/2007. At present (Dec/2009), maximum beam current with 'Crab ON' achieves 1200mA for HER (High Energy Ring, electron) and 1640mA for LER (Low Energy Ring, positron), respectively. RF trip rate per day due to crab cavity during 'physics run' was 2.8/day for HER and 0.4/day for LER at the beginning, and is 0.8/day for HER and 0.1/day for LER at present, respectively. Although Piezo actuator was frequently broken down at the beam abort with RF trip of the crab cavity, it was controlled stably by only LLRF (Low Level RF) feed-back system without Piezo actuator. Maximum HOM (Higher Order Mode) power, which is measured at HOM dampers made from ferrite, is 9.1kW for HER and 14.6kW for LER at the maximum beam current, respectively. LER crab voltage, which had suddenly dropped from 1.50MV to 1.10MV on March/2007, was gradually recovered from 1.14MV to 1.33MV in 2008.

 

slides icon

Slides

 
TUPEB011 KEKB Superconducting Accelerating Cavities and Beam Studies for Super-KEKB 1536
 
  • Y. Morita, K. Akai, T. Furuya, A. Kabe, S. Mitsunobu, M. Nishiwaki, S. Takano
    KEK, Ibaraki
 
 

Eight superconducting accelerating cavities have been stably operated in the KEKB with sufficiently low trip rates. Two superconducting crab cavities were installed in 2007 and soon the crab crossing operation started. Recently the KEKB luminosity reached the world record of 2.1 x 1034 cm-1s-1. Stable operations of the accelerating cavities contributed for the luminosity increase. For the future Super-KEKB, we are developing a high power coupler for an input power of 600 kW and a HOM damper for RF power absorption more than 30 kW. The Super-KEKB requires RF operations with the high beam loading and the low RF voltage than the present KEKB operation. To suppress klystron output powers the external Q value has to be reduced. A new operation was proposed for superconducting cavities. In order to keep high RF voltages in each cavity, some cavities reverse its synchronous beam phase while the total RF voltage is kept as low as the required one. Beam studies were successfully carried out with one cavity reversed its synchronous beam phase.

 
TUPE091 Recent Progress in the Energy Recovery Linac Project in Japan 2338
 
  • S. Sakanaka, M. Akemoto, T. Aoto, D.A. Arakawa, S. Asaoka, A. Enomoto, S. Fukuda, K. Furukawa, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, M. Isawa, E. Kako, T. Kasuga, H. Katagiri, H. Kawata, Y. Kobayashi, Y. Kojima, T. Matsumoto, H. Matsushita, S. Michizono, T.M. Mitsuhashi, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, E. Nakamura, K. Nakanishi, K. Nakao, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, S. Ohsawa, T. Ozaki, C.O. Pak, H. Sakai, H. Sasaki, Y. Sato, K. Satoh, M. Satoh, T. Shidara, M. Shimada, T. Shioya, T. Shishido, T. Suwada, M. Tadano, T. Takahashi, R. Takai, T. Takenaka, Y. Tanimoto, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, S. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida
    KEK, Ibaraki
  • M. Adachi, M. Katoh, H. Zen
    UVSOR, Okazaki
  • R. Hajima, R. Nagai, N. Nishimori, M. Sawamura
    JAEA/ERL, Ibaraki
  • H. Hanaki
    JASRI/SPring-8, Hyogo-ken
  • H. Iijima, M. Kuriki
    HU/AdSM, Higashi-Hiroshima
  • I. Ito, H. Kudoh, N. Nakamura, S. Shibuya, K. Shinoe, H. Takaki
    ISSP/SRL, Chiba
  • H. Kurisu
    Yamaguchi University, Ube-Shi
  • M. Kuwahara, T. Nakanishi, S. Okumi
    Nagoya University, Nagoya
  • S. Matsuba
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima
  • T. Muto
    Tohoku University, School of Scinece, Sendai
  • K. Torizuka, D. Yoshitomi
    AIST, Tsukuba
 
 

Future synchrotron light source using a 5-GeV-class energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting active R&D efforts for that. We are developing super-brilliant DC photocathode guns, two types of cryomodules for both injector and main superconducting linacs, 1.3 GHz high CW-power rf sources, and other important components. We are also constructing a compact ERL for demonstrating the recirculation of low-emittance, high-current beams using those key components. We present our recent progress in this project.

 
TUPE094 Cooling Test of ERL HOM Absorber 2344
 
  • M. Sawamura
    JAEA/ERL, Ibaraki
  • T. Furuya, H. Sakai, K. Umemori
    KEK, Ibaraki
  • K. Shinoe
    ISSP/SRL, Chiba
 
 

HOM absorbers are one of the key components to determine the ERL cavity performance to reduce the HOM problem for the high current operation. When a beam line HOM damper is installed inside the cryomodule, the HOM absorber is cooled down to liquid nitrogen temperature. The RF absorber used for the HOM absorber is required to have good frequency and temperature properties at low temperature. The RF absorber was selected by permittivity and permeability measurement of some ferrites and ceramics from room temperature to 40 K. The HOM absorber is designed by optimizing the parameters such as length, thickness and position with microwave simulation codes. The HOM absorber test model was designed and fabricated to test the RF, mechanical, cooling and temperature properties.

 
WEPEC015 Development of a Prototype Module for the ERL Superconducting Main Linac at KEK 2923
 
  • T. Furuya, K. Hara, K. Hosoyama, Y. Kojima, H. Nakai, K. Nakanishi, H. Sakai, K. Umemori
    KEK, Ibaraki
  • M. Sawamura
    JAEA/ERL, Ibaraki
  • K. Shinoe
    ISSP/SRL, Chiba
 
 

A prototype module including a couple of 1.3 GHz superconducting 9-cell cavities has been designed as the main linac of cERL which is the test facility to establish the basic ERL technology at KEK. The shape of 9-cell Nb structure has been optimized to accelerate a CW beam of 100 mA with sufficiently damped higher order modes (HOM) which is achieved by adopting an eccentric fluted beam pipe and a cylindrical beam pipe of a large diameter of 123 mm. Extracted HOMs are absorbed by the ferrite cylinders bonded on the copper beam pipes by HIP process. A power coupler with double disk-ceramics has been developed to transfer an RF of 20 kW CW to the cavity in full reflection. The test results of fabrication, cooling and RF performance for these components are integrated as the prototype module of the main linac for cERL facility.

 
WEPEC028 Cavity Diagnostics using Rotating Mapping System for 1.3GHz ERL 9-Cell Superconducting Cavity 2950
 
  • H. Sakai, T. Furuya, S. Sakanaka, T. Takahashi, K. Umemori
    KEK, Ibaraki
  • M. Sawamura
    JAEA/ERL, Ibaraki
  • K. Shinoe
    ISSP/SRL, Chiba
 
 

We are developing the superconducting (SC) cavity for Energy Recovery Linac (ERL) in Japan. In order to survey the electron emission and the heating spot of the cavity inner surface in detail, cavity diagnostics with the rotating mapping system was applied. Two types of sensors, one of which is the carbon resistor and the other is the Si PIN photo diode, were set to detect the temperature rise and electron emission. By rotating the sensor arrays around the cavity axis, a lot of information is obtained all over the cavity surface in detail. This paper reports the results of vertical tests by using this rotating mapping system with Nb 9-cell ERL cavity.

 
WEPEC029 Power Coupler Development for ERL Main LINAC in Japan 2953
 
  • H. Sakai, T. Furuya, S. Sakanaka, T. Takahashi, K. Umemori
    KEK, Ibaraki
  • A. Ishii, N. Nakamura, K. Shinoe
    ISSP/SRL, Chiba
  • M. Sawamura
    JAEA/ERL, Ibaraki
 
 

We started to develop an input power coupler for a 1.3GHz ERL superconducting cavity for ERL main linac. Required input power is about 20kW for the cavity acceleration field of 20MV/m and the beam current of 100mA in energy recovery operation. The input coupler is designed based on the STF-BL input coupler, especially choke-mode type ceramic window was applied. After that some modifications are applied for the CW 20kW power operation. We fabricated input coupler components such as ceramic windows and bellows and carried out the high-power test of the components by using a 30kW IOT power source and a test stand constructed.

 
WEPEC030 Results of Vertical Tests for KEK-ERL 9-cell Superconducting Cavity 2956
 
  • K. Umemori, T. Furuya, H. Sakai, T. Takahashi
    KEK, Ibaraki
  • M. Sawamura
    JAEA/ERL, Ibaraki
  • K. Shinoe
    ISSP/SRL, Chiba
 
 

In order to verify the technology needed for ERL main linac cavities, we fabricated a prototype of L-band 9-cell KEK-ERL superconducting cavity. For the ERL, along with high gradient and high Q-value, strong HOM damping is required. Its cell shape is optimized for the HOM damping. The cavity has large irises of 80 mm diameter, large beampipes of 120 mm and 100 mm diameter and the eccentric fluted beampipe. After a series of surface treatment, such as annealing, electro-polishing, high-pressure-rinsing and baking, several vertical tests have been performed. As for cavity diagnostics, a rotating X-ray and temperature mapping system was constructed. The cavity performance was limited to less than 20 MV/m by the field emissions. The X-ray distributions caused by field emission were clearly observed by X-ray mapping system. In this report, we summarize the recent results of the vertical tests.

 
WEPEC031 Observation of Resonance Mode in Coaxial-type Input Coupler 2959
 
  • K. Umemori, T. Furuya, H. Sakai
    KEK, Ibaraki
  • M. Sawamura
    JAEA/ERL, Ibaraki
  • K. Shinoe
    ISSP/SRL, Chiba
 
 

The coaxial-type input couplers are frequently used for accelerators, since it can successfully propagate high power of RF. Thus we have been developing the coaxial-type input coupler for ERL main linac, operated at 1.3 GHz. When performing high power test of its component, however, we suffered from the heat load due to unexpected loss. A resonance just around 1.3 GHz was found from the low-level measurement. In order to investigate the cause of that resonance, precise calculation was done with MW-studio and HFSS codes. Both codes showed one of dipole modes exists at around 1.3 GHz, near coaxial ceramic window. Details of the mode were further investigated. It showed that the resonant frequency of it depends on, for example, the thickness of the ceramic, the permittivity of the ceramic, and the sizes of inner and outer conductors. In this report, we summarize the experimental observations and the some results from the calculations.

 
WEOAMH02 Recent Progress of KEKB 2372
 
  • Y. Funakoshi, T. Abe, K. Akai, Y. Cai, K. Ebihara, K. Egawa, A. Enomoto, J.W. Flanagan, H. Fukuma, K. Furukawa, T. Furuya, J. Haba, T. Ieiri, N. Iida, H. Ikeda, T. Ishibashi, M. Iwasaki, T. Kageyama, S. Kamada, T. Kamitani, S. Kato, M. Kikuchi, E. Kikutani, H. Koiso, M. Masuzawa, T. Mimashi, T. Miura, A. Morita, T.T. Nakamura, K. Nakanishi, M. Nishiwaki, Y. Ogawa, K. Ohmi, Y. Ohnishi, N. Ohuchi, K. Oide, T. Oki, M. Ono, M. Satoh, Y. Seimiya, K. Shibata, M. Suetake, Y. Suetsugu, T. Sugimura, Y. Susaki, T. Suwada, M. Tawada, M. Tejima, M. Tobiyama, N. Tokuda, S. Uehara, S. Uno, Y. Yamamoto, Y. Yano, K. Yokoyama, M. Yoshida, S.I. Yoshimoto, D.M. Zhou, Z.G. Zong
    KEK, Ibaraki
 
 

KEKB is an e-/e+ collider for the study of B physics and is also used for machine studies for future machines. The peak luminosity of KEKB, which is the world-highest value, has been still increasing. This report summarizes recent progress at KEKB.

 

slides icon

Slides