The 1959 Nature article by Giuseppe Cocconi and Phil Morrison<sup>1</sup> provided the theoretical underpinnings for SETI,
accompanied in 1960 by Project Ozma<sup>2</sup>, the first radio search for signals by Frank Drake at the National Radio
Astronomy Observatory (NRAO). Well over 100 search programs have been conducted since that time, primarily at
radio and optical wavelengths, (see www.seti.org/searcharchives) without any successful signal detection. Some have
suggested that this means humans are alone in the cosmos. But that is far too strong a conclusion to draw from far too
small an observational sampling. Instead of concluding that intelligent life on Earth is unique, it is more appropriate to
note that in 50 years our ability to search for electromagnetic signals has improved by at least 14 orders of magnitude
and that these improvements are still occurring at an exponential rate. At the SETI Institute we are in the process of reinventing
the way we search in order to fully utilize these technological enhancements. We are now building the
setiQuest community and we intend to get the world involved in making our searches better. We need to find ways to
harness the intelligence of all Earthlings in order to better seek out extraterrestrial intelligence. If we do it right, we just
might succeed, and we might also change how we see ourselves, and make our own world a better place.
The Allen Telescope Array (ATA) is a Large-Number-Small-Diameter radio telescope array currently with 42 individual
antennas and 5 independent back-end science systems (2 imaging FX correlators and 3 time domain beam formers) located
at the Hat Creek Radio Observatory (HCRO). The goal of the ATA is to run multiple back-ends simultaneously, supporting
multiple science projects commensally. The primary software control systems are based on a combination of Java, JRuby
and Ruby on Rails. The primary control API is simplified to provide easy integration with new back-end systems while
the lower layers of the software stack are handled by a master observing system. Scheduling observations for the ATA is
based on finding a union between the science needs of multiple projects and automatically determining an efficient path
to operating the various sub-components to meet those needs. When completed, the ATA is expected to be a world-class
radio telescope, combining dedicated SETI projects with numerous radio astronomy science projects.
The Allen Telescope Array, originally called the One Hectare Telescope (1hT)  will be a large array radio telescope whose novel characteristics will be a wide field of view (3.5 deg-GHz HPBW), continuous frequency coverage of 0.5 - 11 GHz, four dual-linear polarization output bands of 100 MHz each, four beams in each band, two 100 MHz spectral correlators for two of the bands, and hardware for RFI mitigation built in. Its scientific motivation is for deep SETI searches and, at the same time, a variety of other radio astronomy projects, including transient (e.g. pulsar) studies, HI mapping of the Milky Way and nearby galaxies, Zeeman studies of the galactic magnetic field in a number of transitions, mapping of long chain molecules in molecular clouds, mapping of the decrement in the cosmic background radiation toward galaxy clusters, and observation of HI absorption toward quasars at redshifts up to z=2. The array is planned for 350 6.1-meter dishes giving a physical collecting area of about 10,000 square meters. The large number of components reduces the price with economies of scale. The front end receiver is a single cryogenically cooled MIMIC Low Noise Amplifier covering the whole band. The feed is a wide-band log periodic feed of novel design, and the reflector system is an offset Gregorian for minimum sidelobes and spillover. All preliminary and critical design reviews have been completed. Three complete antennas with feeds and receivers are under test, and an array of 33 antennas is under construction at the Hat Creek Radio Observatory for the end of 2004. The present plan is to have a total of about 200 antennas completed by the summer of 2006 and the balance of the array finished before the end of the decade.
We review a variety off-the-shelf single board computers being considered for application in the Allen Telescope Array (ATA) for antenna control. The evaluation process used the following procedure: we developed an equivalent small program on each computer. This program communicates over a local area network (Ethernet) to a remote host, and makes some simple tests of the network bandwidth. The controllers are evaluated according to 1) the measured performance and 2) the time it takes to develop the software. Based on these tests we rate each controller and choose one based on the Ajile aJ-100 processor for application at the ATA.
The Rapid Prototyping Array (RPA) is a toy radio telescope located 30 miles from U. C. Berkeley in Lafayette, CA. It serves primarily as a software development test bed for the Allen Telescope Array (ATA). We have developed a minimally functional prototype of the ATA control system founded on C++, Java, and a CORBA-based distributed architecture. The system controls RPA pointing, electronics, and data processing, culminating in a real-time software correlator (i.e. an imaging system). This system has helped us characterize our preliminary design of the ATA control system. Overall, the distributed architecture provided successful, versatile control supporting a wide range of experiments from satellite tracking to beam characterization to celestial observation. However, some weaknesses in the CORBA communications layer were identified, and the synergies of mixing C++ and Java were balanced by paradigm mismatch between the languages. We learned that Java was as fast as C++ and supported more ready-made libraries. Based on these experiences, we changed our design to eliminate CORBA and build a pure Java system at the ATA, which is now under development.
We use the ex-situ technique of magneto-optical spectroscopy to characterize MBE-grown Co, Co-Pt, and evaporated Co-Ni films and show that subtle changes in the structural and chemical order as well as changes in the crystallographic properties can substantially affect the magneto-optical spectra. These can be viewed as a sensitive probe of the spin-polarized electronic structure of a magnetic material, which in turn is strongly structure dependent. In particular, we discuss the effect of the crystallographic phase on the spectra of 1000 angstrom thick fcc and hcp Co and fcc and hcp Co<SUB>82</SUB>Ni<SUB>18</SUB> films in the photon energy range 08 - 5.5 eV. In Co<SUB>1-x</SUB>Pt<SUB>x</SUB> alloys, of compositions x approximately equals 0.75 and approximately equals 0.5, large changes in the magneto-optical spectra are observed if chemical ordering is induced either by annealing below the disorder-order transition temperature or by direct growth near the ordering temperature. Other examples are the discovery of a new chemically ordered, hexagonal Co-Pt phase at the composition x approximately equals 0.25 and an unprecedented large Kerr effect in the chemically ordered Fe<SUB>1</SUB>Pt<SUB>1</SUB> (L1<SUB>0</SUB>) phase.
MBE is a powerful synthesis technique for preparation of ordered intermetallic phases since the high rates of surface diffusion allow in-plane chemical ordering to occur at temperatures far below those which are necessary for ordering in bulk samples. This lifting of kinetic constraints enables the phase diagrams to be explored at low temperatures where bulk ordering processes are often too sluggish for phase equilibria to be reached. Specifically, we describe the preparation of epitaxial films (in the thickness range 100 - 1000 angstrom) of ordered intermetallic phases in the Co-Pt and Fe-Pt intermetallic systems. Such phases are of potential importance for magnetic and magneto-optical storage applications. In particular we discuss growth and chemical ordering in epitaxial Co<SUB>1-x</SUB>Pt<SUB>x</SUB> films near x equals 0.25, 0.5, and 0.75 as well as Fe<SUB>1-x</SUB>Pt<SUB>x</SUB> films near x equals 0.5. Depending on growth conditions these phases order spontaneously during growth with resulting changes in the Kerr spectra. Ordering results in large Kerr rotations (approximately 1 degree(s)) in the UV spectral region for the films with x near 0.5.