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Award-winning TRIUMF graduate student prepares for LHC ‘glow up’

31 August 2018

The world’s largest scientific experiment will soon be glowing up.

After nearly a decade of exploration at the frontiers of particle physics (including confirming the long-theorized Higgs boson), CERN’s Large Hadron Collider (LHC) will soon undergo a suite of upgrades, including those to increase its ‘luminosity’ – a parameter that describes the number of particles passing through its experimental chamber at any given time.  

Within particle smashers like the LHC, luminosity is somewhat a measure of collision rate; the LHC’s original design luminosity of (10^34 cm^-2 s^-1) (ten decillion particles passing through a space as wide as a single human hair every second) allows us to study about 600 million particle collisions per second.  

Upgrades slated for the LHC’s 2019-2020 shutdown are the first step in a years-long plan to increase that luminosity by up to a factor of seven.

However, intensifying the atom smasher’s collision frequency is only one part of the ‘glow up’ upgrade.

LHC scientists must also increase the capacity of the experiment’s detectors, complex envelopes of detectors and circuitry that surround the point of collision like layers of an onion and register the subatomic shrapnel emanating from nearly two billion impacts per second. 

Scientists in motion

That part of the upgrade falls to scientists and students like Sébastien Rettie, a TRIUMF graduate student, Vanier scholar, and University of British Columbia (UBC) Ph.D. candidate. Rettie is currently working on detector technology for ATLAS, one of the major particle detectors at the LHC. His work on the multilayered detector system (the New Muon Small Wheels [NSWs] system) will in part allow ATLAS to cope with the proposed increase in data.  

Rettie is also the recent recipient of a Mitacs Globalink Research award, a program for up-and-coming researchers and innovators in Canada. Mitacs is a national not-for-profit organization that has been delivering research and training programs in Canada for nearly two decades. The Mitacs Globalink program supports international research exchanges through funding and internship programs for senior undergraduate and graduate students.

Rettie’s Mitacs award win will enable him to travel to the Weizmann Institute of Science in Israel and focus on his ATLAS upgrade efforts (he’s departing just after Labour Day!).

We caught up with Rettie to learn more about his work on ATLAS and his Mitacs win:

1) Were you always interested in physics, even as a child or young adult? Was there an experience or moment that made you want to pursue a career in science?

I always liked math and science as a child, but really came to love physics during CÉGEP, when I took my first ‘Modern Physics’ course. I remember there was a point in high school where my physics teacher asked us if we thought we could divide a grain of sand infinitely. I answered yes, and was amazed that the answer was in fact no; that there were these ‘elementary particles’ that could not be divided any further. I thought that was extremely fascinating, and I think from that point on I knew I wanted to continue having these ‘Aha!’ moments, and that a career in science was a great way to accomplish this.

2) In addition to contributing to world-renowned research initiatives, you’ve worked hard to attain some incredible achievements throughout your academic and professional career. What is it that drives/motivates you?

It’s working with a collaboration that has the common goal of answering the big questions that drives me. I find there is something extremely satisfying in sitting down and really understanding a complex problem in its entirety.

3) Can you summarize the part of your research being recognized by the Mitacs award?

The proposed research project while at the Weizmann Institute of Science will have the main goal of contributing to the upgrade of the ATLAS detector. In particular, a very important part of the ATLAS detector, the New Muon Small Wheel, needs to be installed to cope with the forthcoming LHC upgrade to faster data-taking rates.

Without the NSW, the LHC would be forced to throw away invaluable data, or reduce the rate at which it collects data; both of these options are extremely undesirable from a physics standpoint. The first step in this effort is understanding the detector technology at play in the NSW, so-called small-strip Thin Gap Chambers (sTGC).

 While at the Weizmann Institute of Science, I will analyze test beam data from sTGC detectors. The final result will be the characterization of their performance both in terms of data-taking capabilities and muon reconstruction precision, allowing the data-taking with the ATLAS detector to continue without loss of data. Being able to contribute to the continuous data-taking carried out by ATLAS is definitely a great source of motivation for me.

4) How will the Mitacs award contribute to your work?

The Mitacs award will allow me to travel to the Weizmann Institute of Science in order to learn from world-leading experts in sTGC detector technology, and fully concentrate on research during my stay.

5) Mitacs has long been a proponent of elevating collaborative research in Canada. What impact do organizations like Mitacs have on communities of scientists and researchers, and on how these groups collaborate?

Organizations like Mitacs are great for fostering international collaborations because they provide the opportunity for students to travel and experience new research communities and cultures. They also provide the opportunity for researchers at foreign institutes to benefit from Canadian students’ contributions to their research group.

Sébastien will be embarking on his trip following Labour Day. Congratulations, Sébastien, and good luck!