About the accelerator
The accelerator lab came to life in Holmes Hall in 1979 using a 400 kV high voltage engineering Van de Graaff accelerator. In 1985 the lab moved on campus to Bill Hall. In 1994 we received a grant from NSF to purchase an entirely new accelerator, and the old machine was retired (at least from Connecticut College!) in May 1995. The new accelerator is a 1 million volt Pelletron built by National Electrostatics Corp installed in the F. W. Olin Science Center on Aug. 1, 1995.
Two major research projects
We have two major research projects in the lab. The first involves PIXE (proton-induced x-ray emission) in which we do material analysis. The second involves excitations induced in ion-molecule collisions.
The laboratory is a primary site for student involvement in the research. On average, there are usually 4 students working in the lab at any time. The student work has led to honors theses, independent studies and publications in peer-reviewed journals.
The PIXE research involves spectral analysis of the x-rays emitted from a sample after being struck with a proton beam. From the spectra we can determine the elemental composition of the sample. Also, after calibration using a known standard, we can also determine percent weights of each element detected.
PIXE has been used in laboratory for analysis of archaeological materials and also for lake bed sediments. Currently, we are doing a collaborative project with Art History and examining ancient Greek and Roman pottery.
The work in ion-molecule collisions involves looking at photon emission from excited states formed during the collision process. Past work has focused on molecular targets of astrophysical interest. This work culminated in the publication of two papers dealing with water as a target, the latest was written by students and published in Physical Review (http://journals.aps.org/pra/abstract/10.1103/PhysRevA.83.042701). The research has now taken on a new direction where the targets are RNA and DNA bases. This has obvious application to both radiation damage of biologically important molecules and aslo in terms of radiation therapy treatments.
Recent Student Research
All the publications from the laboratory for the last 20 years have been in major journals such as Physical Review and Journal of Geophysical Research, and all these papers have been co-authored by the students. The new work on RNA and DNA bases was started by Olha Townsend '13 and Morgane Amat '14. It is now being continued by Rebecca Napolitano '15, Jonathan Stark '15, and Allisa Dalpe '16. We expect the first publication on this work within a year's time.
Doug Thompson, Department Chair
Box 5553, Dept. of Physics, Astronomy and Geophysics
270 Mohegan Ave.
New London, CT 06320