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The vertical neutron camera (VNC) has been developed to measure neutron emission profile in deuterium plasmas of the large helical device (LHD). The experiment on spatial resolution evaluation for VNC was carried out in November 2016 by using a 252Cf neutron source of 800 MBq. The neutron source was introduced into the LHD vacuum vessel through an aluminum pipe from an upper diagnostics port to the equatorial plane. The source was placed at the following two positions. The first position is just on the cylindrical collimator axis, and the second position is in the middle of two neighboring collimator axes. The stilbene scintillation detectors are aligned radially at the collimator end to detect unscattered fast-neutrons generated in a deuterium plasma. The 3-D neutron transport calculations by using a general-purpose Monte Carlo N-particle code 6 reproduced the experimentally obtained neutron counting rate, indicating that VNC has sufficient spatial resolution and the crosstalk between two neighboring collimators is a fairly small fraction. It is expected that the VNC on LHD will function as a tool for the study on the radial transport of energetic ions. [ABSTRACT FROM AUTHOR]

A passive optical network (PON) protection scheme is needed to ensure the system reliability required for business use, as PON is based on sharing a single fiber via an optical distribution network. Protection switching time is an important factor for business applications because it defines the service outage duration when a failure occurs. In this paper, we propose a PON protection scheme that enables the service outage duration to be reduced. We demonstrate Type B protection for a time and wavelength division multiplexed PON system and discuss the service outage duration. [ABSTRACT FROM PUBLISHER]

We demonstrate and investigate resolution improvement of optical quantization using soliton self-frequency shift (SSFS) and optical coding using optical interconnection for an all-optical analog-to-digital conversion (ADC). Incorporating spectral compression into the optical quantization allows us to improve the resolution bit according to the spectral compression ratio with keeping its throughput. The proposed scheme consists of optical quantization using SSFS and self-phase modulation (SPM) induced spectral compression and optical coding using optical interconnection based on a binary conversion table. In optical quantization, the powers of input signals are discriminated by referring to the center wavelengths after the SSFS. The compression of the spectral width allows us to emphasize the differences of their center wavelengths, and improve the number of resolution bits. Optical interconnection generates a bit-parallel binary code by appropriate allocation of a level identification signal, which is provided as a result of optical quantization. Experimental results show the eight periods transfer function, that means, the four read-out bit operation of the proposed scheme in binary code. Simulation results indicate that the proposed optical quantization has the potential of 100 GS/s and 4-b resolution, which could surpass the electrical bandwidth limitations. [ABSTRACT FROM PUBLISHER]