Inframetrics infrared scanner upgraded to a 12-bit digital thermography system for heat load measurements at nuclear fusion experiments

Abstract

A commercially available Inframetrics Scanner (Modell 760) has been upgraded to 12-bit resolution in order to derive heat fluxes on tokamak devices (TEXTOR-94). The temperature resolution is high enough to detect—at the same camera settings—the small sawtoothing heat flux modulation and the large disruptive heat fluxes. Eight new boards have been developed and installed at TEXTOR-94 to perform the measurement, transmit the data from the experiment to the control room, and store the data in a PC. To ensure reliable data transmission, the data stream (1.1 MSPS) is transferred via optical fibers from the camera to the PC in the control room. The PC receives timing information from the TEXTOR-94 timing system such that a synchronization of the camera clock and the experimental clock is guaranteed. The new system includes a time reference to correct a small frequency drift of the original Inframetrics scanner. This feature permits to compare the heat flux with signals from other TEXTOR-94 diagnostics during fast events like disruptions for which the camera can also be operated in the fast line scan mode.