Performance of the multiband imaging photometer for SIRTF

We describe the test approaches and results for the Multiband Imaging Photometer for SIRTF. To verify the performance within a `faster, better, cheaper' budget required innovations in the test plan, such as heavy reliance on measurements with optical photons to determine instrument alignment, and use of an integrating sphere rather than a telescope to feed the completed instrument at its operating temperature. The tests of the completed instrument were conducted in a cryostat of unique design that allowed us to achieve the ultra-low background levels the instrument will encounter in space. We controlled the instrument through simulators of the mission operations control system and the SIRTF spacecraft electronics, and used cabling virtually identical to that which will be used in SIRTF. This realistic environment led to confidence in the ultimate operability of the instrument. The test philosophy allowed complete verification of the instrument performance and showed it to be similar to pre-integration predictions and to meet the instrument requirements

Reduction Algorithms for the Multiband Imaging Photometer for Spitzer

We describe the data reduction algorithms for the Multiband Imaging Photometer for Spitzer (MIPS) instrument. These algorithms were based on extensive preflight testing and modeling of the Si:As (24 micron) and Ge:Ga (70 and 160 micron) arrays in MIPS and have been refined based on initial flight data. The behaviors we describe are typical of state-of-the-art infrared focal planes operated in the low backgrounds of space. The Ge arrays are bulk photoconductors and therefore show a variety of artifacts that must be removed to calibrate the data. The Si array, while better behaved than the Ge arrays, does show a handful of artifacts that also must be removed to calibrate the data. The data reduction to remove these effects is divided into three parts. The first part converts the non-destructively read data ramps into slopes while removing artifacts with time constants of the order of the exposure time. The second part calibrates the slope measurements while removing artifacts with time constants longer than the exposure time. The third part uses the redundancy inherit in the MIPS observing modes to improve the artifact removal iteratively. For each of these steps, we illustrate the relevant laboratory experiments or theoretical arguments along with the mathematical approaches taken to calibrate the data. Finally, we describe how these preflight algorithms have performed on actual flight data.Comment: 21 pages, 16 figures, PASP accepted (May 2005 issue), version of paper with full resolution images is available at http://dirty.as.arizona.edu/~kgordon/papers/PS_files/mips_dra.pd

First look at the Fomalhaut debris disk with the Spitzer Space Telescope

We present Spitzer Space Telescope early release observations of Fomalhaut, a nearby A-type star with dusty circumstellar debris. The disk is spatially resolved at 24, 70, and 160 � m using the Multiband Imaging Photometer for Spitzer (MIPS). While the disk orientation and outer radius are comparable to values measured in the submillimeter, the disk inner radius cannot be precisely defined: the central hole in the submillimeter ring is at least partially filled with emission from warm dust, seen inSpitzerInfrared Spectrograph (IRS) 17.5‐34 � m spectra and MIPS 24 � m images. The disk surface brightness becomes increasingly asymmetric toward shorter wavelengths, with the south-southeast ansa always brighter than the north-northwest one. This asymmetry may reflect perturbations on the disk by an unseen interior planet. Subject headingg circumstellar matter — infrared: stars — planetary systems — stars: individual (Fomalhaut

On-orbit performance of the MIPS instrument

The Multiband Imaging Photometer for Spitzer (MIPS) provides long wavelength capability for the mission, in imaging bands at 24, 70, and 160 microns and measurements of spectral energy distributions between 52 and 100 microns at a spectral resolution of about 7%. By using true detector arrays in each band, it provides both critical sampling of the Spitzer point spread function and relatively large imaging fields of view, allowing for substantial advances in sensitivity, angular resolution, and efficiency of areal coverage compared with previous space far-infrared capabilities. The Si:As BIB 24 micron array has excellent photometric properties, and measurements with rms relative errors of 1% or better can be obtained. The two longer wavelength arrays use Ge:Ga detectors with poor photometric stability. However, the use of 1.) a scan mirror to modulate the signals rapidly on these arrays, 2.) a system of on-board stimulators used for a relative calibration approximately every two minutes, and 3.) specialized reduction software result in good photometry with these arrays also, with rms relative errors of less than 10%

Bi-Hemispheric Distribution and Ecology of the Commensal Amphipod \u3ci\u3eLeucothoe nagatai\u3c/i\u3e Ishimaru, 1985 (Crustacea: Leucothoidae)

Reports on the taxonomy and distribution of the amphipod crustacean Leucothoe nagatai , are discussed including significant range extensions from the type locality in the Sea of Japan. This research was based on existing museum specimens, and in situ collections of new material. Originally described from the branchial chamber of the solitary ascidian Styela plicata (), several new ascidian and sponges host species from California and New Zealand are documented for L. nagatai. Molecular studies confirm that northern and southern hemisphere populations are genetically indistinguishable. Color patterns in live and freshly preserved specimens of L. nagatai are diagnostic across its geographic range aiding in identification by nontaxonomists. Feeding habits of leucothoids within their invertebrate hosts are elucidated and discussed. Figures and plates of known invertebrate hosts, color patterns, and taxonomic structures are included

On-orbit performance of the MIPS instrument

The Multiband Imaging Photometer for Spitzer (MIPS) provides long wavelength capability for the mission, in imaging bands at 24, 70, and 160 microns and measurements of spectral energy distributions between 52 and 100 microns at a spectral resolution of about 7%. By using true detector arrays in each band, it provides both critical sampling of the Spitzer point spread function and relatively large imaging fields of view, allowing for substantial advances in sensitivity, angular resolution, and efficiency of areal coverage compared with previous space far-infrared capabilities. The Si:As BIB 24 micron array has excellent photometric properties, and measurements with rms relative errors of 1% or better can be obtained. The two longer wavelength arrays use Ge:Ga detectors with poor photometric stability. However, the use of 1.) a scan mirror to modulate the signals rapidly on these arrays, 2.) a system of on-board stimulators used for a relative calibration approximately every two minutes, and 3.) specialized reduction software result in good photometry with these arrays also, with rms relative errors of less than 10%

Growth and Characterization of Metastable Hexagonal Nickel Thin Films via Plasma-Enhanced Atomic Layer Deposition

There is a great interest in various branches of the advanced materials industry for the development of novel methods (and improvements to existing ones) for the deposition of conformal ultrathin metallic films. In most of these applications, like enhanced solar absorbers and microelectronics, achieving the capacity to deposit a conformal thin film on a three-dimensional structure is an important condition. Plasma-enhanced atomic layer deposition (ALD) is known for its potential for growth of conformal thin films with a precise control over the thickness and its capability for deposition at relatively low temperatures (below 500 °C). This study evaluates the potential of plasma-enhanced ALD for growth of conformal nickel thin films, using bis­(ethylcyclopentadienyl)­nickel and nitrogen/hydrogen plasma as precursors. A comprehensive analysis of the structure, composition, and physical properties of the films was performed. The results indicate that conformal nickel films with low levels of impurity were successfully deposited on sapphire. The films had a roughness of <i>R</i>_a = 1.5 nm and were seen to be under strain. The deposited nickel had a hexagonal crystal structure, with a random in-plane orientation of the grains, while the grains had their <i>c</i>-axes oriented along the normal to the interface. These results pave the way for conformal low-temperature deposition of high-quality nickel thin films on three-dimensional structures