RF and timing reference distribution system for J-PARC linac

Kobayashi, Tetsuya; Chishiro, Etsuji; Anami, Shozo*; Yamaguchi, Seiya*; Michizono, Shinichiro*

Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.320 - 322, 2004/08

J-PARC (Japan Proton Accelerator Complex) linac, which is 300 m long, consists of 324 MHz accelerating section of the upstream and 972 MHz section (as future plan) of the downstream. In the klystron gallery, totally about 60 RF source control stations will stand for the klystrons and solid-state amplifiers. The error of the accelerating field must be within 1 degree in phase and 1% in amplitude. Thus, the high phase stability is required to the RF reference for all of the low-level RF control systems and the beam monitor systems. This paper presents a final design and the summary of the performance evaluation of the RF reference distribution system including the timing control signal distribution for this linac.

RF reference distribution system for the J-PARC linac

Kobayashi, Tetsuya; Chishiro, Etsuji; Anami, Shozo*; Yamaguchi, Seiya*; Michizono, Shinichiro*

Proceedings of 28th Linear Accelerator Meeting in Japan, p.366 - 368, 2003/08

For the J-PARC linac, a 12-MHz RF reference is distributed to 60 low-level RF control systems of klystron stations through optical links. The error of the accelerating field must be within +/- 1 degree in phase and +/ 1% in amplitude. Thus, a very high phase stability (within +/- 0.3 degree in phase) is required to the reference distribution system. New optimized optical components for this linac were developed and the performance of them was tested. The results will be reported. In adition, the timing control signal distribution system for the linac will be illustlated.

Remodeling of diagnostics timing system for JT-60 degassing operation

Oshima, Takayuki; Iwasaki, Keita*; Shimizu, Kazuaki

Heisei-14-Nendo Tokyo Daigaku Sogo Gijutsu Kenkyukai Gijutsu Hokokushu, 3 Pages, 2003/03

no abstracts in English

All under-water experiment on the acoustic characteristic of high temperature ultrasonic transducers

Nakayama, Oukatsu;

JNC TN9400 2000-087, 74 Pages, 2000/07

JNC-TN9400-2000-087.pdf:3.25MB

We have been developing an Ultrasound Doppler Velocimetry technique (UDV), in order to apply thermo-hydraulic measurement in sodium. A feasibility study had been conducted to identify development subjects of sensor and signal processing. Thus, high temperature ultrasonic transducers were manufactured to use in water and sodium tests, which will be scheduled to optimize an algorism of signal processing and to improve the characteristic of the transducer. ln this report, we described the results of an experiment on the acoustic characteristic of transducer in water. The results are as follows : (1)The ultrasound beam profile of the transducer relating to the characteristic of velocity profile measurement using scattering ultrasound wave was obtained. The estimation of ultrasound beam profile in liquid and an ultrasound near-field region were introduced from these experimental data, (2)lt was confirmed that the frequency's spectrum of transducers are adequate for the design requirement of flow velocity range. The specifications of a transmitter and receiver for a transducer were identified, such as the amplitude gain for scattered ultrasound signal and the frequency resolution for Doppler sift signal. (3)The spatial resolution of the ultrasound beam was estimated to evaluate the accuracy of now profile measurement on UDV system.

Passive electromagnetic NDE for mechanical damage inspection by detecting leakage magnetic flux; II An experimental study on the correlation of natural magnetization and mechanical damages in the SUS304 stainless steel

; Aoto, Kazumi; ;

JNC TN9400 2000-022, 46 Pages, 2000/03

JNC-TN9400-2000-022.pdf:3.2MB

ln this report, a study on the behaviors of the magnetization induced by mechanical damages is carried out. By introducing mechanical damages to a test-piece with a tension or/and a zero, tension fatigue testing and measuring the corresponding leakage flux signal, natural magnetization change is proved and found increasing with the mechanical damages (viz. plastic deformation or fatigue damages) though a saturation occurs when damage gets too large. From the experimental results of fatigue testing utilizing test-pieces with a central slit, it was verified that observing the natural leakage flux density (leakage flux without applying external magnetic field) is a reasonable way to identify fatigue cracks. A feature parameter (area of the B hysteresis curve) of the in-situ magnetic field signal measured during the fatigue testing is proposed for predicting the fatigue damages, which is found depending on the cyclic number of the applied loading. At last, residual magnetic fields of a magnetized test-piece are also measured and found depending on the applied plastic deformation in case that the plastic strain is not too small. From these experimental results, it is found that the approach detecting natural magnetization is applicable for monitoring the damage status though it may be not efficient for a scanning inspection concerning its small signal magnitude. On the other hand, the method employing permanent magnet is robust against the environment noise but possibly not valid for the ISl of a structural component with a relative low damage level. For practical application, efforts to evaluate the feasibility of the proposed method are necessary for more testing conditions especially its suitability in a practical environment.

An experimental study of sodium aerosol detection sensitivity by laser induced breakdown spectroscopy

;

JNC TN9400 2000-020, 54 Pages, 1999/11

JNC-TN9400-2000-020.pdf:2.36MB

A Laser-induced breakdown spectroscopy Leak Detection technique (abbreviated LLD) of sodium is accomplished by plasmafying the sodium aerosol, and then selectively detecting the sodium specific optical spectrum. This method is potentially more reliable as a means of detecting of sodium small leakage. This report, describes test results of detection characteristics using sodium aerosol, carried out to verify the principle of LLD in addition to evaluating the response under various conditions. 0ur main objective is to examine the applicability of LLD for small sodium leakage. The main results are as follows; (1)We confirmed the principle of LLD, specifically detecting the sodium optical spectru.m. (2)The relation between LLD fluorescence intensity and sodium aerosol concentration is nearly proportional within a relatively Na concentration ranges 10 10 g/cm. (3)The LLD signal appeared insensitive to the effect of sampling gas flow rate, oxygen concentration, and humidity in the examined range. ln fact, a high S/N ratio is obtained for small sodium leakage, and the reliability of the leakage detection is high, because LLD showed sensitive to sodium concentration. From these results and others discussed in this report, LLD appears to be an applicable technique in small leakage detection both in terms of response and reliabilily in the leakage phase.

None

Horita, M.*; Hokari, T.*

JNC TJ7440 99-022, 378 Pages, 1999/06

JNC-TJ7440-99-022.pdf:14.69MB

no abstracts in English

Demonstration study on shielding safety analysis code (VI)

Sawamura, Sadashi*

JNC TJ1400 99-002, 73 Pages, 1999/03

JNC-TJ1400-99-002.pdf:2.34MB

no abstracts in English

None

*; *; *; *

JNC TJ7440 99-001, 151 Pages, 1999/01

JNC-TJ7440-99-001.pdf:10.35MB

no abstracts in English

An Approach to Reconstruction of a Natural Crack using Signals of Eddy Current Testing, 1; Reconstruction of an Idealized Crack

JNC TN9400 99-009, 39 Pages, 1998/12

JNC-TN9400-99-009.pdf:1.12MB

In this paper, an approach to the reconstruction of an idealized natural crack of non-vanishing conductivity is proposed with use of signals of eddy current testing. Two numerical models are introduced at first for modeling a Stress Corrosion Crack (SCC) in order it possibly to be represented by a set of crack parameters. A method for rapid prediction of the eddy current testing signals arisen from these idealized cracks is given then by extending a knowledge based fast forward solver developed by authors to the case of a non-vanishing conductivity. On the other hand, the inverse algorithm of conjugate gradient method is improved to reconstruct the crack parameters and is implemented with the pick-up signals and gradients calculated by using the rapid forward solver. Several examples are presented finally for validating the proposed strategy. The results verified that both of the models can give reasonable reconstruction results in case of a low noise level. The model concerning the touch of crack surfaces with a conducting band region surrounded by the crack edge, however, is proved more efficient than the model using a conductivity distribution from the point of view of both reconstruction speed and accuracy.