Accelerator Laboratory

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.

View a slide show of the Daghlian ion accelerator.

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.

PIXE

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.

Ion-Molecule Collisions

This work has recently been supported under a NASA-EPSCOR. In this research we are examining ion-molecule collisions that have astrophysical relevance. In the recent past we have done work on SO2, and CO2 as target molecules. Our current work involves the use of the water molecule as a target. This is due to water's preponderance in comets and also as a constituent in the Jovian moon Europa.

Recent Student Work

Our students recently presented the results of their work in both PIXE and ion-molecule collisions at the 2008 National Conference on Undergraduate Research. Also, the initial results of the proton-water molecule work has been published in Physical Review A: “Excitations from dissociative fragments produced in H+ + H2O collisions”, Phys. Rev. A, 79 , 012704-1, (2009), with three students as co-authors.