Early Days of SIS Receivers

The modern era of millimeter and submillimeter spectral line observations and interferometry started at end of the 1979 with the invention of the Superconductor-Insulator-Superconductor (SIS) mixer. Tom Phillips co-invented this device while working at Bell Telephone Labs (BTL) in Murray Hill, NJ. His group built the first astronomically useful SIS heterodyne receiver which was deployed on the Leighton 10.4 m telescope at the Caltech Owens Valley Radio Observatory (OVRO) in the same year. Tom Phillips joined the Caltech faculty in the early 1980s where his group continues to lead the way in developing state-of-the-art SIS receivers throughout the millimeter and submillimeter wavelength bands. The rapid progress in millimeter and submillimeter astronomy during 1980s required developments on many fronts including the theoretical understanding of the device physics, advances in device fabrication, microwave and radio frequency (RF) circuit design, mixer block construction, development of wideband low-noise intermediate frequency (IF) amplifiers and the telescopes used for making the observations. Many groups around the world made important contributions to this field but the groups at Caltech and the Jet Propulsion Laboratory (JPL) under the leadership of Tom Phillips made major contributions in all of these areas. The end-to-end understanding and developments from the theoretical device physics to the astronomical observations and interpretation has made this group uniquely productive

An Annotated Bibliography on Children of Divorce

Articles and chapters and books relating to children of divorced parents

Directory of Services Relevant to Children of Divorce

Services available to children of divorce in Omaha, Nebraska area

A Low Noise Receiver for Submillimeter Astronomy

A broadband, low noise heterodyne receiver, suitable for astronomical use, has been built using a Pb alloy superconducting tunnel junction (SIS). The RF coupling is quasioptical via a bowtie antenna on a quartz lens and is accomplished without any tuning elements. In its preliminary version the double sideband receiver noise temperature rises from 205 K at 116 GHz to 815 K at 466 GHz. This is the most sensitive broadband receiver yet reported for sub-mm wavelengths. Its multi-octave sensitivity and low local oscillator power requirements make this receiver ideal for remote ground observatories or space-borne telescopes such as NASA's Large Deployable Reflector. A version of this receiver is now being built for NASA's Kuiper Airborne Observatory

Optimizing double-sideband SIS quasiparticle mixers

Calculations based on the quantum theory of mixing in single-particle tunnel junctions show that there is a fairly simple strategy for optimizing the performance of double-sideband superconductor-insulator-superconductor (SIS) quasiparticle mixers. The best mixer noise temperature is obtained when the signal source is matched to the local oscillator (LO) admittance of the junction. This applies over a very wide range of LO and DC bias conditions. These calculations support the contention that it is the energy dissipation in the device which is important in determining the noise performance, not the small signal admittance or the power gain. This appears to be another demonstration of the Callen and Welton fluctuation-dissipation theorem. which states that it is the dissipation of energy which is responsible for the noise generation in a wide range of devices, and it is this energy dissipation mechanism to which the signal should be coupled to minimize the noise

American Indian Women and Sexual Assault: Challenges and New Opportunities

This article informs social workers about sexual violence against American Indian and Alaskan Native (AI/AN) women and the policy reforms in the 2010 Tribal Law and Order Act (TLOA). It describes the unmet needs of AI/AN survivors, reviews the TLOA reforms on sexual assault in relation to social work and public health principles, discusses the complementary roles for social workers and public health practitioners in reform efforts, and offers guidance for professional participation that emphasizes tribal sovereignty, indigenous capacity, and cultural competence

A λ = 1.3 Millimeter Aperture Synthesis Molecular Line Survey of Orion Kleinmann-Low

We present a 1".3 spatial resolution interferometric spectral line survey of the core of the Orion molecular cloud, obtained with the OVRO millimeter array. Covering 4 GHz bandwidth in total, the survey contains ~100 emission lines from 18 chemical species. The spatial distributions of a number of molecules point to source I near the IRc2 complex as the dominant energy source in the region but do not rule out the presence of additional lower luminosity objects. At arcsecond resolution, the offsets between dust emission and various molecular tracers suggest that the spectacular "hot core" emission in the Orion core arises via the heating and ablation of material from the surfaces of very high density clumps located ≳500 AU from source I and traced by the dust emission. We find no evidence for a strong internal heating source within the hot core condensation(s)

Collaboration: Faculty Perspective

From the chapter introduction: Over the past decade and a half, I have worked with many undergraduates as teaching assistants, research assistants on my projects, and advisees who conduct research for honors or other advanced programs. However, in very few cases have I had the special opportunity to genuinely collaborate with a student on research. The materials that follow define collaboration and set it apart from other modes of working with undergraduates, discuss selection processes, goals, challenges, and advantages of collaboration, and provide examples from my work with an outstanding undergraduate student, Joseph Hamm. I conclude this chapter with specific recommendations about teaching ethical behavior, ethical concerns in collaboration with undergraduates, and recognition of the larger mission of collaboration beyond the context of course requirements or the university as a whole

The CARMA correlator

The Combined Array for Research in Millimeter-wave Astronomy (CARMA) requires a flexible correlator to process the data from up to 23 telescopes and up to 8GHz of receiver bandwidth. The Caltech Owens Valley Broadband Reconfigurable Array (COBRA) correlator, developed for use at the Owens Valley millimeter-wave array and being used by the Sunyaev-Zeldovich Array (SZA), will be adapted for use by CARMA. The COBRA correlator system, a hybrid analog-digital design, consisting of downconverters, digitizers and correlators will be presented in this paper. The downconverters receive an input IF of 1-9GHz and produce a selectable output bandwidth of 62.5MHz, 125MHz, 250MHz, or 500MHz. The downconverter output is digitized at 1Gsample/s to 2-bits per sample. The digitized data is optionally digitally filtered to produce bands narrower than 62.5MHz (down to 2MHz). The digital correlator system is a lag- or XF-based system implemented using Field-Programmable Gate Arrays (FPGAs). The digital system implements delay lines, calculates the autocorrelations for each antenna, and the cross-correlations for each baseline. The number of lags, and hence spectral channels, produced by the system is a function of the input bandwidth; with the 500MHz band having the coarsest resolution, and the narrowest bandwidths having the finest resolution