hideo itozaki - Academia.edu (original) (raw)

Papers by hideo itozaki

Gamma ray irradiation tests on high- SQUIDs were carried out to examine their behavior under nucl... more Gamma ray irradiation tests on high- SQUIDs were carried out to examine their behavior under nuclear reactor environments. The SQUIDs were made of HoBa Cu O superconducting thin films on SrTiO substrates. Some were encapsulated in glass fiber rein forced epoxy resin. Gamma ray irradiation was performed with a Co-60 gamma ray source. Irradiation dose rates used were 8.1 to 12.2 10 Gy/h (1.0 to 1.5 10 R/h) and the maximum absorption dose was about 10.4 MGy. During and after the irradiation, the noise of the output of the SQUIDs was measured with a power spectrum analyzer. The modulation voltage did not change until a total irradiation dose of about 3 MGy, after which it decreased slightly. We conclude that high- SQUIDs are resistant to gamma ray irradiation and thus the application of high- SQUIDs as sensors for reactor component inspection is promising.

Japanese Journal of Applied Physics, 1990

Chemical, Biological, Radiological, Nuclear, and Explosives (CBRNE) Sensing XVII, 2016

A bottled liquid explosive scanner has been developed using near infrared technology for glass or... more A bottled liquid explosive scanner has been developed using near infrared technology for glass or PET bottles and ultrasound technology for metal cans. It has database of near infrared absorbance spectra and sound velocities of various liquids. Scanned liquids can be identified by using this database. This device has been certified by ECAC and installed at Japanese international airport.

Applied Superconductivity, 1998

High-Tc SQUID was applied for the detection of magnetized fine iron particles in motion. Two type... more High-Tc SQUID was applied for the detection of magnetized fine iron particles in motion. Two types of high-Tc SQUIDs with different magnetic field resolution were used. One is a large washer type and the other is a flux transformer type. It was shown that the magnetic field measured by the SQUID is proportional to the third power of diameter and is inversely proportional to the distance between the SQUID and the particle, as given by the electro-magnetic formula. As a result of the high magnetic field resolution and the quick response to transients, the SQUID detected an iron particle with 50μm diameter at 800m/min. This technique with high sensitive SQUID could be applicable to the in-line detection of iron particles inclusion in wires and fibers, as well as in food and medicine. This will contribute to an increased production yield and cope with the production liability.

Superconductor Science and Technology, 2014

Journal of the Korean Physical Society, 2006

Bulletin of the Japan Institute of Metals, 1990

Superconductor Science and Technology, 2006

It is important to suppress both environmental noise and system noise as much as possible when a ... more It is important to suppress both environmental noise and system noise as much as possible when a weak magnetic signal is measured by a superconducting quantum interference device (SQUID). Environmental noise can be suppressed by using magnetic shielding or a gradiometer. However, we still have system noise produced by the electronics such as coils and amplifiers, even if we use perfect magnetic shielding or a gradiometer. This research has been aimed at reducing this system noise signal in measured data using digital signal processing. Two SQUIDs are placed close together, and the same magnetic field is detected with these two SQUIDs simultaneously. The outputs of these SQUID magnetometers, however, are different from each other, because the system noise included in the signal has random phase, amplitude and frequency for each respective SQUID. By extracting the in-phase components from these two SQUID output signals, the system noise signal can be reduced, and as a result, the signal from the measuring object in which we are interested can be obtained. An adaptive digital filter (ADF) algorithm was used for this extraction of the in-phase components. When the signal-to-noise ratio was 0.5, the noise signal was decreased by about 10 dB by this processing. In addition, the frequency division by the wavelet transform was used to raise the performance of the in-phase component extraction. The noise signal is reduced at each frequency band, and each of the band elements is reconstructed by an inverse wavelet transform to obtain the signal of the object. The noise removal performance was improved to about −20 dB when this method was used. In addition, the waveform distortion became lower than that processed without wavelet transform.

Physics Procedia, 2015

Superconducting quantum interference devices (SQUIDs) have been applied to various magnetic sensi... more Superconducting quantum interference devices (SQUIDs) have been applied to various magnetic sensing. An rf-SQUID can measure magnetic signals by applying external rf-magnetic field whose frequency is tuned to its resonance. Our rf-SQUID having the outer diameter of 3.5 mm needed a substrate resonator to operate it within the operation frequency range of our using FLL electronics. The designs of the rf-SQUID and the resonator were critical to the resonant frequency and the effective area. In this paper, the outer diameter dependence of the resonant frequency and the effective area were investigated by both the electromagnetic simulations and the experiments. The results showed that the rf-SQUID having the larger outer diameter has the smaller resonant frequency and the larger effective area. The rf-SQUIDs having the larger outer diameter were fabricated according to the simulation results. They could be operated within the operation frequency range even though a resonator was omitted.

Infrared Technology and Applications XXXV, 2009

Liquid explosives have been used in terrorism recently. Inspection of bottles becomes very import... more Liquid explosives have been used in terrorism recently. Inspection of bottles becomes very important, because these liquid explosive or it raw materials can be carried by bottles easily. Hydrogen peroxide is typical raw materials of liquid explosives. It was difficult to evaluate concentration of hydrogen peroxide in the drink in the bottle, because of similarity of its optical properties to those of water. Using near infrared spectrum and multivariate statistical analysis, concentration of percent order of hydrogen peroxide in the bottle can be evaluated from outside of the bottle instantly. Hydrogen peroxide has been detected in not only a clear PET or glass bottle but also a colored glass bottle. Hydrogen peroxide mixed by soft drink such as coke or orange juice with pulp also detected by this method easily. This technique can be applied to inspection of a bottle at airport security so on.

Anti-personnel Landmine Detection for Humanitarian Demining

A Nuclear quadrupole resonance detector has been developed. This detector targets to RDX, a high ... more A Nuclear quadrupole resonance detector has been developed. This detector targets to RDX, a high explosive inside an anti-personnel landmine, buried up to 15 cm deep. This detector works well outside an electromagnetically shielded room. It was also mounted an anti-mine vehicle and remotely controlled mine detection is demonstrated in public.