a picture of me

David Gallacher

PhD Candidate in Experimental Neutrino Physics 

About Me

Hello and welcome to my personal website! My name is David Gallacher (he/him) and I'm a PhD candidate at McGill University in Montreal, Canada. I am studying experimental particle physics at McGill university working with Dr. Thomas Brunner as part of the Brunner Neutrino Lab. I moved here from Ottawa, Ontario, where I lived for 9 years while attending Carleton University. During my time in Ottawa, I completed an honours BSc in Physics and a MSc in Particle Physics, my supervisor for both BSc and MSc theses' was Dr. Mark Boulay. Over the years in Ottawa I worked in various roles in restaurants; as a cook, bartender, server, and supervisor, around the city and developed a deep love for food and cooking that I enjoy to share with others. Since early 2017 I have been vegan, and I've adopted cooking tasty vegan food for others as my main form of activism. 

The purpose of this website is to share some information about myself, my physics research interests and personal projects.

Current Physics Research Interests

My current research interests are centred around light detection techniques for liquid noble detectors. Liquid noble detectors are scintillation detectors which employ condensed noble gasses such as xenon and argon, the two most popular media. These detectors are used to perform detailed measurements of particle interactions, and because they are easy to purify, they are the perfect target material for rare event search experiments. The photosensor technology of choice for upcoming experiments are called “Silicon Photomultipliers” or SiPMs for short. Testing and characterizing these devices in the cryogenic environment of liquid noble detectors (87-170 K) is one of the focus areas for my research. I am a collaborator on the nEXO Experiment, which will use 50,000 SiPMs sensitive to vacuum ultra-violet light. nEXO will be sealed underground for at least 10 years, so we need to make sure these devices will work for +10 years without major issues. 

At McGill University, I am working as the run coordinator for an R&D liquid xenon experiment called “LoLX”. I am responsible for maintaining the data-acquisition system, organizing data-taking, and developing analysis and data-readout software. LoLX, or “light only liquid xenon” is a small-scale (10 cm) liquid xenon detector which employs SiPM devices to collect xenon scintillation light. LoLX aims to perform detailed characterization measurements of SiPM noise properties in a liquid xenon environment, study novel background rejection techniques for future liquid xenon detectors, such as nEXO, and to measure the scintillation timing properties of liquid xenon, which may be used to improve existing PET scanners. For more details on specific projects I'm working on now in the past, check out the sections below!. If you want to reach out and collaborate on a project, please see my contact info below!

To stay up-tp-date on my research work, follow me on ResearchGate!

Click the button below to download my full CV


Research Projects

Click the panels below to read more about research I've worked on!

nEXO - Next Generation 0vBB Search
Neutrinoless Double Beta Decay
Dark Matter Detector Data Analysis
Fluorescent Materials for Particle Physics
Future Dark Matter Detector R&D
Light Detection for Noble Liquid Detectors  

Software & Programming


MERCI is a modular online/offline waveform analysis software in development for fast implementation and analysis of digitized waveform data for SiPM and PMT based experiment readout. MERCI is being developed by scientists from the Darkside, nEXO and Alpha collaborations for live experimental data analysis. I am one of the lead developers of the project, which is still in its early stages. If you're interested in using or contributing to MERCI please reach out!

ROOT Tutorial & other small projects

I've written and shared a short tutorial for compiling a custom project into ROOT, this is a good starter template for a new compiled ROOT/C++ project and explains things at a lower level than in the ROOT Reference guide materials. I also post other physics programming projects on my GitHub for open use.

Science Outreach

Read through the sections below to see what science outreach program's I've been a part of!

McGill Physics Hackathon

The McGill Physics Hackathon is a unique event where students from highschool to PhD compete to create incredible projects involving computation and physics! For two years I've been the lead organizer for the Hackathon where we've fundraised over $50K to make this event happen. Read through our website below to get a better idea of what the Hackathon entails. 

McGill Physics and TSI Outreach

I've been a member of the McGill Physics and TSI Outreach programs for two years as a science outreach coordinator. We do a lot of really awesome programming for elementary school through to undergraduate students. I've lead the Hackathon as the organizer for two years, and this year I remade the outreach website! Follow the link below to take a look and see our other outreach programs. 

Let's Talk Science

LTS is a national science outreach organization that partners university science students with local elementary and high school's. They bring practical and fun science demonstrations to schools and perform live experiments with the students involved. I volunteered with LTS for 2 years while at Carleton University, and it was a blast! LTS performs a critical service of providing science outreach to underrepresented areas, and has dozens of dedicated excursions to isolated indigenous communities. See below for more information on Let's Talk Science.

Ottawa Science Innovation Challenge 

For two years I volunteered with the Ottawa Science Innovation Challenge. OSIC is a science competition that high school students across Ontario can take part in. The challenge is a great opportunity for interested high school students to get a taste for what real science looks like. Contestants are required to come up with a novel research question, perform a thorough literature review and write an experimental proposal, which is graded by volunteer graduate student researchers. The theme of the competition varies from year to year, but focuses on real cutting edge scientific questions. I volunteered as a guest judge and provided feedback on student’s scientific proposals. This was a great experience, and I was able to learn a lot from the program as well as from the students!



I am a member of the MGAPS (McGill Association of Graduate Physics Students) council at McGill. I previously served as VP Finance and Rutherford Technical and Computing Officer, but have recently been elected President. MGAPS aims to help support and advocate for the 200+ graduate students in physics at McGill. Some highlights of my work with MGAPS include negotiating for an unprecedented stipend increase of almost 25% in 13 months, redesigning the graduate lounge in Rutherford and organizing a soft-skill and computing workshop series for new graduates called STEADY

We organize a lot of fun and social activities too! Check out our website link below for more info.