Justin Robert Carmichael, '08
Project: DC Glow-Discharge Plasma Gun
I did my MQP at Oak Ridge National Laboratory (ORNL) in Oak Ridge, TN through a summer internship program under the guidance of Dr. Robert Welton (ORNL) and Professor Rafael Garcia (WPI). The goal of the project was to design and fabricate a plasma gun electron source to function as an “ignitor” for the H- ion source in use on the Spallation Neutron Source (SNS) accelerator. The objective of designing the gun was not only to aid in the H- ion source plasma ignition, but also to provide supplemental electrons for increased performance of the ion source.
Why I chose this project:
The SNS is a new facility run by the Department of Energy (DOE); when I was given the opportunity to be part of an ambitious project of such large scale, the decision was easy for me. The SNS is, at a very basic level, a particle accelerator that “spallates” (or rips apart) mercury atoms with a high energy proton beam. This releases a shower of neutron particles that can be passed through materials to enable scientists to probe materials using advanced neutron scattering techniques. Whether you are a scientist or an engineer, this is a very exciting place to work.
What I learned from my MQP:
The project was very involved; I learned about stress and thermal analysis, finite element methods for computational fluid dynamics, some basic plasma physics, and ion/electron transport optics. In addition, the physics had to be coupled with engineering; this required me to better understand computer-aided design, materials and fabrication processes.
How I have benefitted from my MQP as a person and a student:
In addition to learning about the basics of plasma physics and getting affiliated with engineering principles, the project helped me become more familiar with the general design process. I also enjoyed working with the many very intelligent people at ORNL. Due to this project, I decided to stay at WPI for a Masters in Mechanical Engineering, and after graduating accepted a position at the SNS. I have been working here as an engineer for about three years since then. For someone with a dual background in physics and engineering, this is the ideal job.
What I accomplished: The final gun design worked very well, providing up to 70 mA of supplemental electrons for ignition and source enhancement. This was used for several years at the SNS.
How this project has made me stronger in my field:
Designing plasma devices is very multidisciplinary, often requiring knowledge of stress/thermal analysis, materials, fluid flow, high voltage design, vacuum design, and so on. While the project of course did not make me an expert in any one of these areas, the exposure to all these areas broadened both my physics knowledge and engineering design capabilities. Now, as a practicing engineer, I still routinely come across problems I encountered while undertaking my MQP.
Faculty I worked with and his/her support in my success:
At ORNL Dr. Welton was a fantastic mentor, always going out of his way to help out and guide the project to completion. In addition to the MQP, he would routinely get me involved with other interesting projects. Our team even went to Los Alamos National Laboratory (LANL) to collaborate with their team on a similar project. I had the opportunity to work on other components of the SNS ion source, do some lab testing, and even help out with a project where we made H- ions with a helicon source. The whole team at the SNS was great to work with. At WPI, Professor Garcia helped to organize and analyze the data, and draw conclusions from the resulting plots/figures. Without either mentor, the project would not have been such a success.
Additional comments on WPI's project system:
The project system at WPI is something I really enjoyed and benefited from, and is one of the biggest strengths of the school. The “sufficiency” project in the Humanities and Arts familiarizes students with general writing and oral presentation skills. While I admit I was not initially too thrilled with this requirement, the history course work and project ended up being very interesting. I enjoyed working with Professor Parkinson on my sufficiency paper “A History of Vacuum Science and Technology”.
WPI’s IQP project is also a great program, forcing students to get away from their area of study and work with a team to approach unique problems – often done internationally. I worked with a team in Hong Kong to look at the HK tire recycling program, which was interesting given that HK cannot export the waste and cannot burn them as is common in the US. The sufficiency project, IQP, and MQP were all highlights of my WPI education.