The Infrared Array Camera (IRAC) is one of three focal plane instruments in the Spitzer Space Telescope. IRAC is a four-channel camera that obtains simultaneous broad-band images at 3.6, 4.5, 5.8, and 8.0 µm. Two nearly adjacent 5.2×5.2 arcmin fields of view in the focal plane are viewed by the four channels in pairs (3.6 and 5.8 µm; 4.5 and 8 µm). All four detector arrays in the camera are 256×256 pixels in size, with the two shorter wavelength channels using InSb and the two longer wavelength channels using Si:As IBC detectors. IRAC is a powerful survey instrument because of its high sensitivity, large field of view, and four-color imaging. This paper summarizes the in-flight scientific, technical, and operational performance of IRAC.

This paper presents comparisons between wind measurements in the mesosphere and lower thermosphere by medium‐frequency (MF) radars and by the high‐resolution Doppler imager onboard the Upper Atmosphere Research Satellite (UARS). Because of distinctive observational patterns, time and space averaging, and data processing algorithms, satellites and radars observe the atmosphere from their own perspectives. Because thermal tides are an important part of dynamics in these regions of the atmosphere, tidal determinations from both techniques were given particular attention. Differences and similarities of the two methods are discussed and analyzed.

The Echelon-cross-echelle spectrograph (EXES) is a high spectral resolution, mid-infrared spectrograph designed for and operated on the Stratospheric Observatory for Infrared Astronomy (SOFIA). EXES has multiple operational modes, but is optimized for high spectral resolution. The heart of the instrument is a one meter long, diamond-machined echelon grating. EXES also uses a 10242 Si:As detector optimized for low-background flux. We will discuss the design, operation and performance of EXES.

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14,Using ^C-spiked pyrolytic graphite-coated quartz crucibles for the growth of nine ultra-pure germanium single crystals, we have determined the carbon con tent and distribution in these crystals. Using autoradiography, we observe a rapidly decreasing carbon cluster concentration in successively grown crystals. Nuclear radiation detectors made from the crystals measure the betas from the internal"^ decay ing l^c nuclei wiih close to 100Z efficiency. An average value for the total carbon concentration [14c+i:Cj is -2x10 14 cnr 3 , a valje substantially larger than expected from earlier metallurgical studies. Contrary to the most recent measurement, we find the shape of the beta spectrum to aqree very well with the statistical shape predicted for allowed transitions.can explain all the observed properties of several of the new centers has been proposed recently.s The model is based on a heavy, substitutional impurity such as copper, oxygen, silicon or carbon trapping a light, interstitial impurity such as hydroqen or lithium in its vicinity (Fig. 1), Th potential well which is trapping the interstitial m --ity is thought to be created by the difference in thi ond length of the substitutional impurity and the ger ianium host lattice. The "rapid quench" centers (as Hall called them) fit the above model and have been n?Tted accord ing to their composition A(H,3i) and D(H • (A stands fr.-acceptor, D for donor). Detector makers, can avoid the formatir.. ut these undesirable centers by cooling slowly after any heating cycle, better even by keeping the device at T = 160"C for 10 to 30 minute* 1 before returning to room temperature.