A pulsed electron paramagnetic resonance spectrometer is described, and applications of the instrument to the determination of longitudinal relaxation times of dilute solutions of free radicals and of spin-labeled proteins using the saturation-recovery method are discussed. The spectrometer employs a bimodal cavity; the pumping and observing microwave powers are coherent; and all modulating frequencies, delays, and aperture widths are derived from a master clock. Free-induction-decay signals may be observed in such equipment, and special techniques are introduced to avoid interference of these signals with the saturation-recovery signals.
A suite of three optical instruments has been developed to observe Comet 9P/Tempel 1, the impact of a dedicated impactor spacecraft, and the resulting crater formation for the Deep Impact mission. The high-resolution instrument (HRI) consists of an f /35 telescope with 10.5 m focal length, and a combined filtered CCD camera and IR spectrometer. The medium-resolution instrument (MRI) consists of an f /17.5 telescope with a 2.1 m focal length feeding a filtered CCD camera. The HRI and MRI are mounted on an instrument platform on the flyby spacecraft, along with the spacecraft star trackers and inertial reference unit. The third instrument is a simple unfiltered CCD camera with the same telescope as MRI, mounted within the impactor spacecraft. All three instruments use a Fairchild split-frame-transfer CCD with 1,024 × 1,024 active pixels. The IR spectrometer is a two-prism (CaF 2 and ZnSe) imaging spectrometer imaged on a Rockwell HAWAII-1R HgCdTe MWIR array. The CCDs and IR FPA are read out and digitized to 14 bits by a set of dedicated instrument electronics, one set per instrument. Each electronics box is controlled by a radiation-hard TSC695F microprocessor. Software running on the microprocessor executes imaging commands from a sequence engine on the spacecraft. Commands and telemetry are transmitted via a MIL-STD-1553 interface, while image data are transmitted to the spacecraft via a low-voltage differential signaling (LVDS) interface standard. The instruments are used as the science instruments and are used for the optical navigation of both spacecraft. This paper presents an overview of the instrument suite designs, functionality, calibration and operational considerations.
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