Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

P: Plasmaphysik

P 22: Poster: Magnetische Fusion, Plasmadiagnostik, Dichte Plasmen

P 22.25: Poster

Dienstag, 19. März 2002, 17:40–18:40, HZO Foyer

Noise investigation of an ultra fast semiconductor-gas discharge infrared converter — •V.M. Marchenko¹, Yu.A. Astrov², S. Matern¹, L.M. Portsel², and H.-G. Purwins¹ — ¹Institute of Applied Physics, Münster University, Germany — ²A.F. Ioffe Physico-Technical Institute, St. Petersburg, Russia

The converter operates in the spectral range of 1.1-3.5 µm and is based on the planar semiconductor-gas discharge (SGD) cell providing ultra fast IR-to-visible conversion with the response time on the microsecond scale. The semiconductor wafer is made of Si:Zn, the 100 µm discharge gap is filled with 100 hPa Ar. The cell is cooled down approximately to 90 K. Noise properties have been studied both in time and space domains. Investigations of the spatial noise and NETD have been carried out by using a low-noise CCD camera capturing output images of the SGD cell. For measuring the temporal noise, a low-noise photomultiplier is used to detect gas discharge radiation from the area of about one resolved pixel. The own noise of the SGD cell is found by comparing signal-noise dependencies obtained at acquiring outgoing light of the cell, on the one hand, with those at observing a thermal radiation source with well describable photon noise, on the other hand. The results indicate that the imager has surprisingly low noise which is very close to the photon-noise limit. Besides, such noise-related specifications have been estimated as normalized detectivity D⁽⋆), noise equivalent irradiance and, when applying the imager in a test thermal imaging system, noise equivalent temperature difference (NETD).