Frontiers In Undergraduate Research Poster Session

Matthew Demas

Abstract Draft 1

The goal of this study is to effectively map the surface of a synthetic diamond wafer that is to be used in the beam line at the GlueX experiment at Jefferson National Laboratory. The topology of the diamond surface is encoded within an interferogram produced by a Michelson interferometer. While most interferograms feature interactions by only two surfaces, our pattern is the result of the superposition of three waves. As a result of this additional wavefront, conventional techniques could not be utilized. Instead a simulated annealing program, which is a method used in general optimization problems, entitled ParSA was called upon. Currently, work is being done to ``tune`` the algorithm to best fit the problem at hand. Preliminary analyses on 50 pixel by 50 pixel test interferograms has provided promising results with solutions being reached within a 24 hour period. Future tests on larger intereferograms are being planned, with runs on the actual 400 pixel by 400 pixel interferogram as the final goal.

Abstract Draft 2

Diamonds are known for both their beauty and their durability. Jefferson National Lab in Newport News, VA has found a way to utilize the diamond's strength to view the beauty of the inside of the atomic nucleus with the hopes of finding exotic forms of matter. By firing very fast electrons at a diamond sheet no thicker than a human hair, high energy particles of light known as photons are produced with a high degree of polarization that can illuminate the constituents of the nucleus known as quarks. The University of Connecticut Nuclear Physics group has responsibility for crafting these extremely thin, high quality diamond wafers. These wafers must be cut from larger stones that are about the size of a human finger, and then carefully machined down to the final thickness. The thinning of these diamonds is extremely challenging, as the diamond's greatest strength also becomes its greatest weakness. The Connecticut Nuclear Physics group has developed a novel technique to assist industrial partners in assessing the quality of the final machining steps, using a technique based on laser interferometry. The images of the diamond surface produced by the interferometer encode the thickness and shape of the diamond surface in a complex way that requires detailed analysis to extract. We have developed a novel software application to analyze these images based on the method of simulated annealing. Being able to image the surface of these diamonds without requiring costly X-ray diffraction measurements allows rapid feedback to the industrial partners as they refine their thinning techniques. Thus, by utilizing a material found to be beautiful by many, the beauty of nature can be brought more clearly into view.

Carl Nettleton

Abstract

The main purpose of this research is to construct a Tagger Microscope for use in the GlueX project. Issues that are currently being addresses include; how to cleave and polish a two millimeter square acrylic optical fibers, how to then couple scintillators to acrylic waveguides, how to couple the scintillator waveguide pair to a SiPM (silicon photomultiplier). Optically clear two competent epoxies are being experimented with to couple the scintillators to the acrylic waveguides. Preliminary testing with optically clear epoxies show promising results, that is, epoxies are proving to be a reliable way to couple the fibers with minimal transmission loss. Designs for a device to couple the scintillator waveguide pair to the SiPMs, called a chimney, are being developed. The prototype chimney is expected to be completed used in further testing in the near future.

Revision

At the Thomas Jefferson National Accelerator Facility in Newport News, Virginia, a team of nuclear physicists has come up with a way to probe the nuclear "glue" that binds quarks together inside protons and neutrons. The probe to be used in this experiment consists of a beam of polarized particles of light called photons with a specific energy close to 10 billion electron-Volts. The University of Connecticut Nuclear Physics group has designed a detector to “tag” the amount energy the photons will have. This detector consists of a large array of closely-packed optical fibers made of a special plastic called "scintillator" that produces a brief flash of light whenever struck by a high-energy particle. These scintillating fibers are coupled to individual photodiodes, which convert the flashes of light into electrical pulses that are recorded during the course of an experiment. Methods and tooling for the construction of the fiber detectors is under development by undergraduate researchers in the Physics Department at Storrs. The immediate goal of this project to construct a scaled-down prototype of the tagging detector, which will be tested under realistic conditions in a photon beam at Jefferson Lab prior to launching the construction of the full-scale detector.