Signal to noise ratio of upgraded imaging bolometer for KSTAR

Abstract

An Infra Red imaging Video Bolometer (IRVB) was installed on KSTAR in 2012 having a similar to 2 mu m x 7cm x 9 cm Pt foil blackened with graphite and a 5 mm x 5 mm aperture located 7.65 cm from the foil with 16 x 12 channels and a time resolution of 10 ms. The IR camera was an Indigo Phoenix (InSb, 320 x 256 pixels, 435 fps, <25 mK). In 2017, the IRVB was upgraded by replacing the IR camera with a FLIR SC7600 (InSb, 640 x 512 pixels, 105 fps, <25 mK). The aperture area was reduced by approximately half to 3.5 mm x 3.5 mm, and the number of channels was quadrupled to 32 x 24. A synthetic image derived using the projection matrix for the upgraded IRVB from a Scrape Off Layer Plasma Simulator (SOLPS) model with 146 kW of total radiated power had a maximum signal of 7.6 W/m(2) and a signal to noise ratio (SNR) of 11. Experimental data for a plasma with parameters similar to the SOLPS model (total radiated power of 158 kW) had a maximum signal of 12.6 W/m(2) and noise equivalent power density (SNR) of 0.9 W/m(2) (14). Published by AIP Publishing.