Faculty Profiles - URITANI Akira

Papers - URITANI Akira

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Fabrication and Characteristics of a High Pressure Tiny Pump for Gas Circulation in Radioactivity Measurement of Gaseous Samples Reviewed

Y. Wu, C. Mori, T. Yamamoto, K. Yanagida, A. Uritani, H. Miyahara, T Aoyama and M.

Radioisotopes Vol. 42 ( 4 ) page： 209-215 1993.4

中性子位置検出器

瓜谷章

Vol. 42 ( 9 ) page： 549-550 1993

Characteristics of a Position-Sensitive Fission Counter and Its Applications Reviewed

C. Mori, A. Uritani, A. Ando, T. Osada, Y. Kuniya, K. Kobayashi, S. Shiroya, C. Ichihara

Kyoto University Research Reactor Institute Progress Report page： 140-141 1993

Radioactivity Measurement of ⁸⁵Kr with Position -sensitive Proportional Counter Reviewed

C. Mori, T Yamamoto, T Suzuki, A. Uritani, K. Yanagida, Y. Wu, T. Watanabe and M. Yoshida

Nuclear Instrument & Methods Vol. A312 ( 1-2 ) page： 189-192 1992.2

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Direct radioactivity measurement of 85Kr is difficult with ionization chambers, since it emits high-energy β-rays (Eβmax = 667 keV) which results in a severe wall effect. Also with proportional counters, the end-effect must be taken into account. The position-sensitive proportional counter (PSPC) method which can eliminate the end-effect was applied to direct measurement of 85Kr radioactivity. In the measurement, logarithmic amplifiers were employed to clearly distinguish between β-ray signals and noise signals, and to eliminate digital error in the calculation of position information. The radioactivity of 85Kr was determined with ±0.80% standard deviation.

Characteristics of a Position-Sensitive Fission Counter and Its Applications Reviewed

C. Mori, A. Ando, A. Uritani, K. Yanagida, Y. Kuniya, C. Ichihara, S. Shiroya, K. Kobayashi

Kyoto University Research Reactor Institute Progress Report page： 138-139 1992

A New Position-sensitive Nuclear Fission Counter with a Convenient Read out Method for Neutron Measurement Reviewed

C. Mori, T Haga and A. Uritani

Nuclear Instrument & Methods Vol. A310 ( 1-2 ) page： 437-440 1991.12

Measurement of Neutron Flux Distribution in Critical Assembly with Position-Sensitive Helium-3 Proportional Counter Reviewed

A. Uritani, C. Mori, T Haga, K. Yanagida N. Marnada, K. Kobayashi, S. Shiroya and C. Ichihara

J. Nuclear Science and Technology Vol. 28 ( 9 ) page： 824-830 1991.9

Highly Reliable Low-level Neutron Detection Using ³He Proportional Counters Reviewed

T. Aoyama, C. Mori, A. Uritani, T. Matsui and K. Naito

Radioisotopes Vol. 40 ( 5 ) page： 189-192 1991.5

Novel Position -sensing Method Using Fast and Slow components in the Output Signal from a Proportional counter Reviewed

A. Uritani, C. Mori, T Watanabe and A. Miyahara

Nuclea Instrument & Methods Vol. A299 ( 1-3 ) page： 231-233 1990.12

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

We have developed a novel position-sensing method of a proportional counter using slow and fast components in the output signal observed at one end of a resistive anode wire of which the other end is grounded through a capacitor. This paper describes the principle of the position sensing and some experimental results. Fairly sufficient characteristics in position resolution and integral linearity were obtained. This method will extend the application field of position-sensitive detectors.

Application of a Logarithmic Amplifier to a Charge-Division-Type Position-sensitive Proportional Counter Reviewed

C. Mori, T Suzuki, A. Uritani, T Yamamoto, K. Yanagida, T Watanabe and M. Yoshida

Nuclear Instrument & Methods Vol. A299 ( 1-3 ) page： 128-132 1990.12

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Fulfillment of both observation of pulses ranging from about 10 mV to 10 V through ADC and carrying out an arithmetic calculation with small digital errors for such digitized pulses is usually difficult, although it is required in measurements using a charge-division-type position-sensitive proportional counter (PSPC). However, the use of a logarithmic pulse amplifier sometimes solves this problem. The advantage of using a logarithmic pulse amplifier is described through the application of the amplifier to absolute-radioactivity measurements of gaseous samples and to the simultaneous measurement of geometrical distributions of neutrons and gamma-rays with the PSPC.

Novel Position Sensing Method Using Fast and Slow Components in an Output Signal from a Proportional Counter Reviewed

A. Uritani and C. Mori

Nuclear Instruments and Methods Vol. A294 ( 3 ) page： 677-678 1990.9

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

We propose a novel position-sensing method using slow and fast components in an output signal observed at one end of a resistive anode wire in a proportional counter in which the other end of the anode wire was grounded through a capacitor. Fairly sufficient characteristics in position resolution and an integral linearity were obtained. This method will extend the application field of a position-sensitive detector.

Development of Position-Sensitive Helium-3 Proportional Counter for Thermal Neutrons with Novel Signal Readout Reviewed

A. Uritani, C. Mori, T Watanabe and A. Miyahara

J. Nuclear Science & Technology Vol. 27 ( 8 ) page： 712-717 1990.8

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

A position sensitive 3He proportional counter for thermal neutrons with a novel signal readout method which has two pre-amplifiers at only one end of the counter body has been developed. It has an advantage for usage in a special environment, such as in a subcritical facility or in water, or for insertion into a narrow space. The characteristics of the counter were evaluated with thermal neutrons. The position resolution was 7 mm with an effective length of 1, 200 mm. The integral non-linearity of position signal was less than 0.5%.

熱中性子用位置検出型比例計数管の開発

瓜谷章、森千鶴夫

放射線 Vol. 16 ( 2 ) page： 80-91 1990.3

Improvement of Signal Readout in Charge Division Type Position Sensitive Proportional Counter Reviewed

A. Uritani, C. Mori, T Watanabe and A. Miyahara

J. Nuclear Science & Technology Vol. 26 ( 12 ) page： 1094-1101 1989.12

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

It is generally difficult to insert a position sensitive proportional counter (PSPC) with a conventional charge division in a narrow space, or to work the counter under special environments, such as in water or in a reactor. We improved the position signal readout to make it possible to use a PSPC under such environments. A position signal was extracted from only one end of an anode wire by grounding the other end through a capacitor and a total charge signal was obtained from twelve cathode wires stretched parallel to the anode wire, so that two pre-amplifiers were able to be connected at only one end of the counter. The character-istics of the PSPC with the improved signal readout were examined with X-rays. The position resolution was 1.3 mm with an effective length of 550 mm, and depended on the X-ray injection position. A non-linearity of position signals was less than 0.2%.

Multi element Position Sensitive Proportional Counter for Measurement of Tritium Labeled Gas Movement Reviewed

C. Mori, A. Uritani and T. Watanabe

J. Nuclear Science and Technology Vol. 25 ( 4 ) page： 341-349 1988.4

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

A multielement position sensitive proportional counter was developed for the measurement of 3H labeled gas movement in a pipe by internal counting. The counter consists of an outer cylindrical pipe with an inner diameter of 40 mm, seven resistive stainless steel anode wires with a diameter of 22μm, and 24 cathode wires with a diameter of 120μm. These wires divide the radial cross section of the pipe into seven regions. Since each region independently works as a position sensitive proportional counter and the seven resistive anode wires are connected in series through lump resistors, the region and the axial position where a β-decay event occurred can be known by a simple operation upon the charge signals obtained from two preamplifiers. The axial position resolution for 3H β-rays was 9 mm FWHM. Demonstrative experiments were performed for the flow and diffusion of 3H labeled ethane in the counter pipe.

Charge Transfer Process and Sputtering Process of Self-sustaining alkali Metal Coating on Metal Surface Reviewed

A. R. Krauss, O. Auciello, A. Uritani, M. Valentine, R. Mendelsohn and D. M. Gruen

Nuclear Instrument & Methods Vol. B27 ( 1 ) page： 209-220 1987.6

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

It is well known that adsorption of electronegative or electropositive atoms on a metal surface results in charge transfer between the metal conduction band and the adsorbate atom. This charge transfer results in the formation of a coverage-dependent image dipole and a consequent change in the work function and adsorbate binding energy. Additionally, the secondary electron yield and the charge state of surface atoms desorbed by thermal, electron impact or ion impact desorption processes are closely related to the effective adsorbate charge.

We discuss here the effect of Gibbsian segregation as a means of producing similar effects for electropositive (alkali metal) layers on a number of metal substrates. Classical chemisorption theory is used as a means of estimating the adsorbate effective charge and the results are compared with models used to predict the secondary ion fraction of sputtered atoms. The resulting concept of self-sustaining sputter-resistant coatings is analyzed in the context of applications to the fusion environment as well as to, e.g., materials for high current electrical contacts.

New Partial Pressure Gauge for Helium and Deuterium Using the Ion Backscattering Principle Reviewed

K. Akaishi, Y Kubota, A. Uritani and Y Hori

J. Vacuum Science and Technology Vol. A5 ( 4 ) page： 2444-2446 1987.6

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

A new partial pressure gauge is proposed that is capable of measuring partial pressures of He and D2 gases in the mixture. The gauge consists of a conventional ion scattering spectrometer with a Wien filter. The influence of the residual gases CH4 and H2O on the pressure measurements of D2 and He in this gauge is discussed.

Implantation and Replacement of Hydrogen Isotopes Implanted in 304 Stainless Steel Vacuum Wall under RF Discharge and RF-DC Glow Discharge Reviewed

K. Akaishi, Y Kubota, A. Uritani and Y Hori

J. Nuclear Material Vol. 145-147 page： 275-279 1987.2

Conceptual Design and Engineering Aspect of Tokamak Burning Plasma Experiments -the R-projects, Chapter 5 Vacuum System

A. Uritani and K. Akaishi

Nuclear Engineering Design/Fusion Vol. 42 ( 2 ) page： 405-409 1987.1

R & D Efforts for the R-TOKAMAK Components

A. Miyahara, Y. Fujii-e, K. Kamada, Y. Oka, O. Kaneko, K. Sakurai, T. Kuroda, K.N.Sato, A. Uritani, K. Akaishi and H. Amano

Nuclear Engineering Design/Fusion Vol. 42 ( 2 ) page： 357 1987.1

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

In parallel to the conceptual design of the R-tokamak, research and development efforts on
the systems and the components have been carried out to obtain scopes to realize the device.
Because we intended to introduce DT fuels into the device, the items of research and
development works are quite different to that of non-burning machines. Alminium alloy
developments to avoid activations by 14 MeV neutron irradiations, tritium safe handling and
vacuum system with tritium are examples of this category. Beside specific requirement directly
caused by DT introduction, highly reliable operation of the machine is strongly requested,
because it is the necessary condition to perform experiments safely. However, these efforts are
still in an early stage of investigation and many efforts are needed to prepare a rigid data base
tokamak operation with reacting plasma.

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