IPAC2012 - List of Authors (Kobayashi, T.)

Paper	Title	Page
WEPPD050	Upgrade of the RF Reference Distribution System for 400 MeV LINAC at J-PARC	2630
	K. Futatsukawa, Z. Fang, Y. Fukui, T. Kobayashi, S. Michizono KEK, Ibaraki, Japan F. Sato, S. Shinozaki JAEA/J-PARC, Tokai-mura, Japan
	In J-PARC, the accelerator systems are controlled using the 12 MHz master clock in center control building. In the present J-PARC Linac, the negative hydrogen is accelerated by 181 MeV using the RFQ, DTLs, and SDTLs which have the resonance frequency of 324 MHz. The low-level radio frequency (LLRF) system is based on the reference signal of 312 MHz (LO) synchronized with the master clock. We are planning to upgrade Linac by the accelerated energy to 400 MeV by the installation of ACS cavities with the resonance frequency of 972 MHz. Then, not only 312 MHz but also 960 MHz reference signals are necessary. Therefore, a new RF reference signal oscillator was installed at J-PARC LINAC. The phase noise of the output signal in this module was measured by the signal source analyzer. The jitter of the output signal, which was estimated from the integration of phase noise from 10 Hz to 1 MHz, becomes about 40 fs and was two order smaller than that of the old system (about 1700 fs) by the installation of new oscillator and the optimization of the path of the master clock. It can be expected to improve the operating ratio in J-PARC LINAC.

THPPC009	Investigation of the Approaches to Measure the RF Cable Attenuation	3290
	K. Futatsukawa, Z. Fang, Y. Fukui, T. Kobayashi, S. Michizono KEK, Ibaraki, Japan F. Sato, S. Shinozaki JAEA/J-PARC, Tokai-mura, Japan
	In the accelerator facilities, many RF cables are used for the various purposes such as the transmission system and the cavity monitor. The knowledge of the power attenuation in those cables is important role to control RF. In general, the cable attenuation is measured from S parameters to use a network analyzer. However, the control system is located far from the place of the cavities, and it difficult to measure by a network analyzer. Then we investigated other methods to measure the RF cable attenuation.

THPPC079	Prototype Performance of Digital LLRF Control System for SuperKEKB	3470
	T. Kobayashi, K. Akai, K. Ebihara, A. Kabe, K. Nakanishi, M. Nishiwaki, J.-I. Odagiri KEK, Ibaraki, Japan H. Deguchi, K. Harumatsu, K. Hayashi, J. Nishio, M. Ryoshi Mitsubishi Electric TOKKI Systems, Amagasaki, Hyogo, Japan
	For the SuperKEKB project, a new LLRF control system has been developed to realize high accuracy and flexibility. It is an FPGA-based digital RF feedback control system using 16-bit ADC's, which works on the μTCA platform. In this μTCA-module, the Linux-OS runs then it performs as the EPICS-IOC. This LLRF system is available to both of normal-conducting cavity and super-conducting cavity. A prototype of the LLRF control system for the SuperKEKB was produced. The feedback control stability, temperature characteristics and cavity-tuner control performance are evaluated. The evaluation results and future issue for the operation will be presented in this report. The amplitude and phase stability in the feedback control is 0.03% and 0.02 degrees, respectively. It is sufficiently stable for the SuperKEKB. However, the temperature dependency is not small for the required stability. Its countermeasures are under consideration.

Paper

Title

Page

Upgrade of the RF Reference Distribution System for 400 MeV LINAC at J-PARC

2630

K. Futatsukawa, Z. Fang, Y. Fukui, T. Kobayashi, S. Michizono
KEK, Ibaraki, Japan
F. Sato, S. Shinozaki
JAEA/J-PARC, Tokai-mura, Japan

In J-PARC, the accelerator systems are controlled using the 12 MHz master clock in center control building. In the present J-PARC Linac, the negative hydrogen is accelerated by 181 MeV using the RFQ, DTLs, and SDTLs which have the resonance frequency of 324 MHz. The low-level radio frequency (LLRF) system is based on the reference signal of 312 MHz (LO) synchronized with the master clock. We are planning to upgrade Linac by the accelerated energy to 400 MeV by the installation of ACS cavities with the resonance frequency of 972 MHz. Then, not only 312 MHz but also 960 MHz reference signals are necessary. Therefore, a new RF reference signal oscillator was installed at J-PARC LINAC. The phase noise of the output signal in this module was measured by the signal source analyzer. The jitter of the output signal, which was estimated from the integration of phase noise from 10 Hz to 1 MHz, becomes about 40 fs and was two order smaller than that of the old system (about 1700 fs) by the installation of new oscillator and the optimization of the path of the master clock. It can be expected to improve the operating ratio in J-PARC LINAC.

THPPC009

Investigation of the Approaches to Measure the RF Cable Attenuation

3290

K. Futatsukawa, Z. Fang, Y. Fukui, T. Kobayashi, S. Michizono
KEK, Ibaraki, Japan
F. Sato, S. Shinozaki
JAEA/J-PARC, Tokai-mura, Japan

In the accelerator facilities, many RF cables are used for the various purposes such as the transmission system and the cavity monitor. The knowledge of the power attenuation in those cables is important role to control RF. In general, the cable attenuation is measured from S parameters to use a network analyzer. However, the control system is located far from the place of the cavities, and it difficult to measure by a network analyzer. Then we investigated other methods to measure the RF cable attenuation.

THPPC079

Prototype Performance of Digital LLRF Control System for SuperKEKB

3470

T. Kobayashi, K. Akai, K. Ebihara, A. Kabe, K. Nakanishi, M. Nishiwaki, J.-I. Odagiri
KEK, Ibaraki, Japan
H. Deguchi, K. Harumatsu, K. Hayashi, J. Nishio, M. Ryoshi
Mitsubishi Electric TOKKI Systems, Amagasaki, Hyogo, Japan

For the SuperKEKB project, a new LLRF control system has been developed to realize high accuracy and flexibility. It is an FPGA-based digital RF feedback control system using 16-bit ADC's, which works on the μTCA platform. In this μTCA-module, the Linux-OS runs then it performs as the EPICS-IOC. This LLRF system is available to both of normal-conducting cavity and super-conducting cavity. A prototype of the LLRF control system for the SuperKEKB was produced. The feedback control stability, temperature characteristics and cavity-tuner control performance are evaluated. The evaluation results and future issue for the operation will be presented in this report. The amplitude and phase stability in the feedback control is 0.03% and 0.02 degrees, respectively. It is sufficiently stable for the SuperKEKB. However, the temperature dependency is not small for the required stability. Its countermeasures are under consideration.