A Grille Spectrometer for Measurements near 14 micro.

A new design of the grille spectrometer allows its use for measurements of thermal ir emissions. The grilles are made of self-supporting etched metal foil, and the curved chessboard pattern allows optical chopping of one spectral element at a time by oscillation of the exit grille. Although the effective noise level obtained is as low as 1 erg sec(-1) cm(-2) sr(-1) cm(-1) for an integration time of 448 ms, the specific detectivity of the thermister bolometer appropriate for the large throughput of this instrument is much less than in small throughput versions, and a different detector or detector system will be required to achieve optimum performance.