RIMAS: testing, and categorization of grism spectral performance

The Rapid infrared IMAger Spectrometer (RIMAS) is designed to quickly follow-up near-infrared (NIR) transient events, gamma ray bursts in particular. One way RIMAS will accomplish this mission is with its echelle spectrograph (R≈4000) that contain the first ruled grisms to be used in cross-dispersed mode for NIR astronomy. These ZnSe grisms were recently fabricated at Lawrence Livermore National Lab. This paper discusses the testing and categorization of the echelle spectrographs containing these grisms by comparing the modeled spectra to experimental spectra. This testing resulted in verification of the echelle spectrograph's quality, resolution, and dispersion. Efforts to develop a data reduction pipeline and upgrade RIMAS's detectors are ongoing.