Thushara Perera, PhD
email: tperera (@iwu.edu)
(My Courses Taught page is here)
My primary research interests are astrophysics and precision instrumentation. I worked on the Cryogenic Dark Matter Search (CDMS) experiment as a graduate student and on millimeter-wavelength observations of the early universe (with AzTEC, for example) as a postdoctoral researcher. During that time, I not only learned much about astrophysics, data analysis, and modeling/simulations, but worked with advanced technologies for precision detection/measurement. In particular, I used dilution and helium-3 refrigerators to cool down novel (at the time) detectors read out using superconducting and semiconductor-based circuitry. Upon moving to Illinois Wesleyan in 2008, I decided to set up a research effort which brings together both my astronomical and instrumentation interests.
Since then, I have worked on laboratory studies of the millimeter-wavelength (or Terahertz frequency) optical properties of cosmic dust. I was already familiar with cosmic dust as an important emitter of mm-wave light in the universe. Yet, experimental/observational data on the physical/chemical nature of cosmic dust is minimal; our "knowledge" on cosmic dust consists mainly of theoretical models based on inferences and guesswork. It is widely accepted that far-infrared (far-IR) to mm-wavelengths are the best spectral regimes for studying cosmic dust. In my research lab, we measure the mm-wave and far-IR absorptivity of cosmic analog dusts with high sensitivity in a cryogenically cooled environment.
Supported by a major National Science Foundation grant in 2014, we have built a one-of-kind instrument for the cosmic dust study. It includes (1) a custom-made, ultra-compact Fourier Transform Spectrometer (FTS)—possibly the world's smallest FTS for the frequency range covered (0.1–3 THz); (2) a custom-made sample holder/exchanger where dust samples, embedded in (polyethylene) wax pellets, are cooled to astronomically relevant temperatures (5–50 Kelvin), and (3) a cryogenically cooled detector sensitive to far-IR and mm-waves. For the most part, the cosmic analog dusts are produced with the help of a collaborator in the Illinois Wesleyan Chemistry department (a few samples were obtained from a NASA group and others were purchased). A key point of pride for our experimental operation is that every part of the measurement chain, including the cryostat, was designed by us (we got help from a NASA collaborator on the FTS) and, for the most-part, was built and assembled by us. Therefore, students working in our group become skilled hands-on experimenters/builders. If you want to know more about what we do and the current status of the study, check out our research group's web site.