Rendering of the SPT.


Carlstrom, et al.


Carlstrom, et al.

 

UNDER DEVELOPMENT Experience UNDER DEVELOPMENT

I currently work in the group of Dr. John Carlstrom at the University of Chicago. I am part of the team that built the Sunyaev-Zel'dovich Array (SZA). The SZA is a new interferometric radio-frequency observatory designed to provide detailed observations of galaxy clusters out to the edge of the Universe. I joined the project before the observatory was constructed and played a part in developing the electronics used to control the telescopes, the construction of the observatory, its commissioning observations, and the beginning of the analysis of the science data.

I have prior experience with three other observatories. For my undergraduate senior honor's thesis, I made use of ray-tracing software and astronomical data to correct an observing anomoly with the Submillimeter Polarimeter for Antarctic Remote Observing on the Viper telescope at the South-Pole. This included a deployment to the South Pole in the 2001-2002 Austral Summer. As a research assistant for the National Optical Astronomy Observatory Deep Wide-Field Survey (NDWFS) I contributed to the data reduction pipelines as well as compared models of galaxy evolution against the survey data. Finally, as an undergraduate researcher I undertook a search of archival Hubble Space Telescope data in the hope of identifying supernovae.

I discuss these expereinces in more depth below.

Electronics Development for the SZA

The SZA uses a novel, distributed control system to control the various elements of the observatory. Designed in conjunction with the control system for the Combined Array for Research in Millimeter-wave Astronomy (CARMA), the control system is divided up intelligent nodes each with a specific function. Examples include a node to control the temperature regulation of the electronics enclosure, a node position the tertiary mirrors of the individual telescopes, and a node to control and monitor the cryogenic amplifiers in the radio-frequency receivers. Many nodes were developed jointly for the SZA and CARMA, while some are unique to each array. The majority of the nodes contain an NXP XAC 16-bit processor that hosts an embedded operating system to receive commands and send monitoring data over a control-area-network bus (CANBus).

The implementation of this network is described in Lamb, et al. (2007) and is available in pdf format here.

In particular, I was responsible for the implementation, debugging, and programming for three nodes. In partiuclar, I implemented the SZA Calibrator and Tertiary module (CALTERT), the SZA Receiver Bias module (RXmod), and the Local-oscillator Reference module (LORef). I also assisted with the implementation of the module responsible for tuning and monitoring the Bias-Tuned Gunn oscillator (BTGmod). This process involved developing the XAC operating system using C with a proprietary embedded compiler (TaskingXA) while making sure the physical layout of the electronic components ensured that the cards perfomed according to spec. The cards themselves were a mix of analog (for receiver bias lines), digital (state machines and FPGAs) and radio-frequency (oscillator signals, phase-locked loops, etc.) circuitry, which provided challenges considering the low noise requirements for the science goals of the observatory.

I have experince designing circuits, from the conception phase to installation, including drawing schematics, laying footprints, programming, debugging, and integration. I have made heavy use of the ORCAD PCB Design software, as well as experience programming embedded processors such as the phyCORE XAC3 using embedded compilers (e.g. Tasking). Observatory Comissioning

As part of the construction and commissioning team for the SZA, I had a hand in nearly every aspect of the installation of the

Statistical Methods

I currently work in the group of Dr. John Carlstrom at the University of Chicago.

Prior Experience

Viper Optics Analysis

I currently work in the group of Dr. John Carlstrom at the University of Chicago.

NOAO Deep Wide-field Survey (NDWFS) Data Reduction

I currently work in the group of Dr. John Carlstrom at the University of Chicago.

Galaxy Evolution Research with NDWFS Data

I currently work in the group of Dr. John Carlstrom at the University of Chicago.

Small-scale structure in the Interstellar Medium

I currently work in the group of Dr. John Carlstrom at the University of Chicago.

pPast

I have worked on two main projects in the past. More recently, I worked with Professor Giles Novak of Northwestern University on his submillimeter polarimeter SPARO. Specifically, I investigated a problimatic measurement of the SPARO beamsize. This resulted in my undergraduate thesis. If, for some reason you care, it can be downloaded from my notes page.

During the Summer of 2000, I went to Tucson and worked at the National Optical Astronomy Observatory and worked with Dr. Buell Jannuzi and Dr. Arjun Dey. I spent time on their Deep Wide-Field Survey, crunching a considerable amount of data with Dr. Jannuzi and modeling the evolution of elliptical galaxies over a wide range of redshift space with Dr. Dey.

My efforts with Dr. Dey resulted in a poster at the January 2001 AAS meeting.