Undergraduate Research Profiles

Below, you can read the profiles of a couple University of Chicago physics majors who have been active in research. Enjoy…

adam Adam Anderson

Undergraduate Student: Class of 2010
Majors: Physics and Mathematics
Hometown: Portland, Oregon
Awards (HS): Science Bowl Regional Champion, National Honor Society, National AP Scholar
Awards (Univ): Dean's List, Grainger Senior Scholarship (physics), College Honor Scholarship
Research: Exp Neutrino physics, Condensed Matter Theory
Research Advisors: Ed Blucher, David Thouless (U Washington)

My research at Chicago has been with Ed Blucher on the Double Chooz collaboration, an experiment to measure the theta-1,3 mixing angle involved in neutrino oscillations. During this summer (2009), however, I am taking a break from Chicago to work with David Thouless at the University of Washington, studying Anderson localization on 2- and 3-dimensional lattices due to weak disorder.

During the past 15 years, various experiments have reported convincing evidence that the three flavors of neutrinos change flavor in a phenomenon called "neutrino oscillations". Neutrino physics is a particularly exciting experimental field because of its recent discovery, the fact that oscillations imply a nonzero neutrino mass--a feature not originally contained in the Standard Model--and because the difficulty of detecting neutrinos poses a variety challenges for existing detectors. Double Chooz is an experiment located in northern France, using a commercial nuclear reactor as a source of electron antineutrinos to measure the most poorly-known oscillation parameter called theta-1,3. A better knowledge of theta-1,3 will improve knowledge of the neutrino mass hierarchy and CP violation in the lepton sector.

The group at Chicago has been designing and building the outer veto for the detector. Since neutrinos are so difficult to detect, the detector must be extremely sensitive. It is thus critical to control for backgrounds due to muons and other ambient particles. The outer veto does exactly this by detecting backgrounds so that they can be "vetoed" from the data sample. I initially worked testing scintillator and fiber optic materials for the design of the outer veto. As the design process has been completed, I have worked on computer simulations of the detector to determine ways of rejecting events that mimic the neutrino-detection process. For example, when muons enter the detector, they can be captured by a proton and produce products that look like a neutrino signal. For each of these possible backgrounds it is important to know how significant the background is and whether there are ways of using the detector's features, like timing or position data, to discriminate between real and fake events. Computer simulations are an extremely useful tool for estimating backgrounds and testing strategies for controlling them before data is actually taken.

This summer, my work with David Thouless concerns a phenomenon in condensed matter physics called Anderson localization. In a famous 1958 paper, P.W. Anderson argued that waves in disordered media can become spatially localized instead of diffusing. While localization is a general wave phenomenon, it was originally considered in the context of electrons propagating through disordered materials. In 1985 it was shown that any amount of disorder on a 1-dimensional lattice will produce localization. The situation is more complicated in higher dimensions; in particular, while there are reasons to suspect that even weak disorder produces localization in 2 dimensions, no rigorous proof has been given. I have written numerical simulations of the "tight-binding" model for a particle on a lattice in various dimensions. I am using these simulations as a handle for making probabilistic arguments about localization in the higher-dimensional cases.

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kate Kate Kamdin

Undergraduate Student: Class of 2010
Major: Physics
Hometown: Raleigh, North Carolina
Awards: National Undergrad Fellowship, Dean's List, James Fulton Mclear Scholarship, ILL Space Consortium Grant
Research: High-energy astrophysics, Plasma physics
Research Advisors: Scott Wakely, Stephen Knowlton (Auburn)

In my time as an undergraduate at the University of Chicago, I've worked for the same adviser on a few different projects. Below I give a big-picture description of the projects I've been involved with and then focus specifically on my responsibilities.

At the beginning of my second year I started doing work for the Cosmic Ray Electron Synchrotron Telescope (CREST) collaboration. The CREST experiment is a balloon experiment designed to detect high energy (between 2 and 50 TeV) cosmic ray electrons. The detection of high energy electrons would yield information about the location of nearby cosmic ray sources, a significant finding. Because electrons lose energy at high rates as they propagate through the Galaxy, the distance from which they could originate and still be detected is limited. The spectral shape of the high energy electrons detected by CREST, then, should be affected by the number and distribution of nearby cosmic ray sources. Conversely, if the features of the high energy spectrum do not reflect such behavior, our understanding of cosmic ray sources and propagation will be called into question. My project was to test and characterize the VA32-HDR11 ASIC chip, which was to be used in CREST's electronics -- the chip's first space flight! The process involved testing variables of the chips. I completed gain measurements on several chips and fit the linear region of gain. My findings were presented at a CREST collaboration meeting that December.

The next summer I started working for the Very Energetic Radiation Imaging Telescope Array System (VERITAS). VERITAS is a ground-based gamma-ray observatory with an array of four 12m Cherenkov telescopes for gamma-ray astronomy in the GeV - TeV energy range. VERITAS uses the Air Cherenkov technique to detect high energy gamma rays, again with the purpose of locating and studying sources. When a high energy photon enters the atmosphere it undergoes pair production, creating and electron and a positron. These charged particles interact in the atmosphere through Bremsstrahlung and Compton Scattering, producting more high energy photons, which then undergo pair production, and so on, until the energy essentially runs out. This process creates what is called an Air Shower, a cone of detectable light that all originated from one high energy gamma; the idea is that by detecting the light from a cross section of the cone, the direction the gamma ray originated from can be determined, and thus we can find the original source. My project was to automate the test process for multi-anode (i.e. multi-pixel) photomultiplier tubes (PMT) that are perhaps going to be employed in a next-generation VERITAS, increasing the resolution of the array. The automation involved programming for a translation stage, a pulse height analyser, and data acquisition. I looked at variables such as gain against high voltage and cross talk between anodes.

I am currently participating in a program called the National Undergraduate Fellowship, which funds research in fusion-related plasma physics. I was placed at Auburn University in Auburn, AL, where they have a plasma confinement device called the Compact Toriodal Hybrid (CTH). It is of the stellerator flavor of magnetic confinement devices; the other most commonly used device is called a tokamak. The research at CTH is centered on studying plasma instabilities. We want to understand plasma instabilities because the forefront of current fusion research, the tokamak, is susceptible to such instabilities, which cause disruptions in the fusion plasma and confinement, a key condition for fusion, is lost. I am working on two kinds of plasma diagnostics that deal with X-ray radiation emitted by the plasma, from which it is possible to determine temperature of the plasma. The first is calibrating soft X-ray photo diodes, which will be implemented in CTH to do X-ray tomography, giving a map of the plasma. The second is programming data acquisition for an X-ray spectrometer and integrating the acquisition into the existing framework of that all the other kinds of data that are recorded during a CTH plasma run. X-ray spectrometry can be used to give a temperature measurement of the plasma.

I've really enjoyed doing research and would definitely recommend getting involved. It's a great way to learn new skills and new science in a nurturing environment.

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