Plasma and Fusion Research

Volume 7, 2405007 (2012)

Regular Articles

Improved Data Acquisition Methods for Uninterrupted Signal Monitoring and Ultra-Fast Plasma Diagnostics in LHD

Hideya NAKANISHI, Setsuo IMAZU, Masaki OHSUNA, Mamoru KOJIMA, Miki NONOMURA, Mamoru SHOJI, Masahiko EMOTO, Masanobu YOSHIDA, Chie IWATA, Hitoshi MIYAKE, Yoshio NAGAYAMA and Kazuo KAWAHATA

: National Institute for Fusion Science, Toki 509-5292, Japan

(Received 5 December 2011 / Accepted 13 January 2012 / Published 17 February 2012)

Abstract

To deal with endless data streams acquired in LHD steady-state experiments, the LHD data acquisition system was designed with a simple concept that divides a long pulse into a consecutive series of 10-s “subshots”. Latest digitizers applying high-speed PCI-Express technology, however, output nonstop gigabyte per second data streams whose subshot intervals would be extremely long if 10-s rule was applied. These digitizers need shorter subshot intervals, less than 10-s long. In contrast, steady-state fusion plants need uninterrupted monitoring of the environment and device soundness. They adopt longer subshot lengths of either 10 min or 1 day. To cope with both uninterrupted monitoring and ultra-fast diagnostics, the ability to vary the subshot length according to the type of operation is required. In this study, a design modification that enables variable subshot lengths was implemented and its practical effectiveness in LHD was verified.

Keywords

real-time data acquisition (RT-DAQ), variable subshot, environmental radiation monitoring, device soundness, LABCOM system

DOI: 10.1585/pfr.7.2405007

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This paper may be cited as follows:

Hideya NAKANISHI, Setsuo IMAZU, Masaki OHSUNA, Mamoru KOJIMA, Miki NONOMURA, Mamoru SHOJI, Masahiko EMOTO, Masanobu YOSHIDA, Chie IWATA, Hitoshi MIYAKE, Yoshio NAGAYAMA and Kazuo KAWAHATA, Plasma Fusion Res. 7, 2405007 (2012).