Scott MacEwan is a Ph.D. student in subatomic particle physics at the University of Manitoba.  He is currently working with the Qweak collaboration at the Jefferson Lab in Newport News VA.

Why Physics?

Scott is originally from the Musquodoboit Valley in Nova Scotia (about an hour’s drive from Halifax), where he attended a small high school in a farming community.  When he started university, he thought he might major in chemistry.  However, after taking some courses, he found that his best fit was in physics. 

As an undergraduate at Mount Allison University, Scott participated in a summer research program in Mainz, Germany, and that experience changed everything.  “I had the opportunity to work in experimental nuclear physics (at the age of 20!).  I enjoyed everything about the experience, and I became really interested in that subject area,” says Scott.

When Scott started looking for a Ph.D. program, he contacted different Canadian universities with nuclear sub-atomic physics programs, including the U of M.

“I was impressed with the flexibility of the UM program, and I wanted to be part of a smaller group so that my advisor would have time for me,” recalls Scott.  In the Department of Physics and Astronomy, Scott is supervised by Michael Gericke, and they are both part of the Qweak experiment.

What is Qweak?

Qweak is an experiment where UM researchers have been teaming up with collaborators from around the world, and the project has been 10 years in the making.  As Shelley Page, the UM spokesperson for the group explains: “'Qweak' scatters a high energy electron beam from a liquid hydrogen target to measure the ‘weak charge’ of the proton - a fundamental property, distinct from its more familiar electric charge, which in physics is given the symbol 'Q'”.

The Qweak experiment is a test of the Standard Model.  The Standard Model is a sophisticated mathematical model that successfully describes the currently known fundamental particles in the universe and how they interact.  Without investigation of nature's basic properties, and pushing the improvement of models, there is no improvement in technology.  People working in applied sciences and engineering then use these models, like the Standard Model, to develop and improve products and devices such as electron and proton accelerators used for medical diagnostics and treatment as had, in the past, been the case for x-ray and MRI equipment, but the applications also extend to areas like energy generation and materials science.  As a result, any form of technological progress is dependent on how well the basic mathematical models work, and these, therefore, need to be tested to high accuracy. 

Qweak is a precision test of the Standard Model in the sense that the model makes a certain claim about the value of a weak charge.  A measured result that differs significantly from this claim may serve as some evidence for physics beyond the Standard Model such as String Theory and Supersymmetry.

Qweak is hands-on!

The UM team designed and fabricated the main detectors for the Qweak Experiment at Jefferson Lab (nine, 2 metre long bars made from quartz have been constructed and eight of them arranged like a Ferris wheel).  Scott’s first project for the experiment involved building photomultiplier tube bases.  And when Scott says build, he means it!

“I had to learn how to solder, and how not to burn my hands!  My father is a locksmith and when I was growing up I never thought I was very good at working with my hands.  I never imagined that I could do these things,” he recalls.

“I found when I became part of the Qweak team that there is no real divide between designing, building, maintaining and using equipment.  If you don’t know how to do something, you learn how – you ask.  Inevitably, someone, a graduate student, a Physics faculty member, or a member of the Lab staff, will know what to do and how to help you.” Scott explains.

The various pieces of equipment were built in labs around the world and then brought together and assembled at Jefferson Lab.  When you are working with particle detection, even a 10th of a millimeter makes a difference when putting the pieces together.

Scott moved down to Jefferson Lab in the summer of 2010 to help with the assembly of equipment; the Qweak experiment is scheduled to run until May 2012.

Tremendous opportunity

“Working on Qweak is a tremendous opportunity for me.  In a very short time, I found myself in an ‘expert’ role because of the work I had done with the detectors.  The experience of designing parts and circuits, building, assembling, and acquiring and analyzing data has been amazing.  The UM work with Jefferson Lab means that I make connections with people in the same field from around the world, including some of the people I originally worked with in Germany in my undergrad research experience,” says Scott.

The experiment at Jefferson Lab has the potential to help us make advancements in our understanding of the world, and often this means we are not as sure about the world as we thought we were. 

The journey from Musquodoboit Valley to Jefferson Lab was not a journey Scott had anticipated. 
“You have to really apply yourself to gain an understanding of the basic principles (and the not-so-basic, like quantum mechanics) before you can reap the benefits of this kind of research opportunity,” he explains.

Scott’s advice: “A good attitude is important.  Stick it out; gain confidence.  If you don’t know how to do something – ask for help.  There is always someone willing to help you.”