Friday, December 09, 2016

JMU Physics Shines at SESAPS

The 83rd annual meeting of the Southeastern Section of the American Physical Society (SESAPS) was held in Charlottesville, Virginia, hosted by UVA’s Department of Physics at the Omni Hotel on November 10-12, 2016. The meeting consisted of many contributed talks and posters, including presentations from a few JMU Physics students.

Two students from the Niculescu’s lab and two students from Dr. Hughes’ lab attended this year’s SESAPS. They were: Will Kemmerer and Eric Moeller, and Nick Sipes and Yvonne Kinsella.

Eric Moeller, a JMU Physics senior working with the Niculescu’s, gave his talk titled “Lab Automation and Afterpulsing in Photomultiplier Tubes.”  His talk consisted of an explanation of how the lab is automated, and of how this automation helps him to test the tubes.  By programming machines to “talk to each other automatically,” the amount of time that it takes to run a test has gone from three hours to about forty-five minutes.  “Afterpulsing” is an event that happens during a test run where an extra signal is sent out by the photomultiplier tube that can disrupt data collection.

Will Kemmerer, a JMU Physics junior also working with the Niculescu’s, gave a talk on his research which involves calculating detected quantum efficiency, and the gain multiple for photomultiplier tubes (PMTs). In his talk, he discussed how the overarching goal is to group PMTs by the probability they have to detect a photon, and the output at high voltages which will be used in an accelerator at Jefferson Lab. He also discussed that, since afterpulsing of PMTs does not significantly change as PMTs are heated, they don’t have to worry about the gain multiple changing if the cooling system shuts down while a PMT is in the detector.

JMU Physics Senior, Nick Sipes, at the podium for his
talk on electroless nickel plating.
Another JMU Physics senior, Nick Sipes, also gave a talk on his research done with Dr. Hughes. His talk was titled “Selective Electroless Nickel Plating on PMMA using Chloroform Pre-Treatment.”  Dr. Hughes’ research lab has found in the past that chloroform pre-treatment on a substrate (specifically PMMA) can improve adhesion of gold to it when depositing the metal using magnetron sputtering. Nick’s project looked at a new technique for metal deposition and a new metal that has not been tested by Dr. Hughes’ research lab before. Electroless plating works a lot like electro-plating, except there is no cathode in the solution and your substrate essentially acts as the cathode. Ultimately, Nick discussed that he found that electroless plating of Nickel onto PMMA is improved with the use of chloroform exposure prior to the  metal deposition.

Yvonne Kinsella presented her poster titled “Adhesion of Au Thin Films on PMMA and Other Substrates.”   The main focus of the poster was on the process used for testing how well the gold thin films adhere to a substrate. That process is to polish the Au off the substrate and to quantify it either by using a UV-Vis spectrophotometer or by scanning images of the samples and running a program written in MATLAB which converts the image into threshold and then counts the darker pixels (the idea is that the darker pixels are where the gold is on the surface and as the samples are polished that number should decrease).   Mainly, the poster discussed this process and polishing data for the case when PMMA is a substrate however, the use of glass was also discussed.  In the future, she hopes to work with different polymer substrates to see if the results are similar to what has been found for PMMA so far.

By presenting research at this year’s SESAPS, these students have represented the JMU Department of Physics & Astronomy and shown what is going on in our department to the larger scientific community.  Additionally, they have been awarded experience of presenting research in a professional environment, which will help them in their future beyond JMU.