Today we bring you an interview with Alie Craplet, a PhD student in the High Energy Physics group who also did her undergrad at Imperial!
Describe your path into physics. Who were your inspirations?
My path into physics was actually one of indecisiveness. I come from the French system, I’m originally French, and I always liked science – I was good at it, but without really knowing what I wanted to do with my life. I got told that Physics keeps as many doors open as a subject can. At first, I wanted to do Maths and then I realised that I was not that mathsy, so I went into Theoretical Physics instead. I knew I wanted to stay in London, so for me it was almost more of a university-based approach rather than a subject-based approach. I was interested in Quantum Physics; I’d read a few books about it. My grandad actually did a PhD in Physics in France many years ago, but it’s not like a family trade – he never really talked to me about it, I knew he had done it, but I wouldn’t say he inspired me.
I think first day of uni, I thought: I’m not going to carry on with Physics, this is too complicated and difficult. Coming from the French system, I had to understand English and understand the courses. I remember that my first year at Imperial was especially difficult. I came back every day thinking I was going to fail and it was going to be terrible. In the end, I didn’t fail. Even though I was never very good at exams, I sort of started finding things that were interesting to me, especially projects.
It was only in my second year that I discovered I actually liked Physics and It was what I wanted to do later on. This personal breakthrough happened in the second-year Interferometry lab: back then (and we still have this problem), the stages that move [the interferometer arms] actually don’t move in a linear nor in a smooth manner – they make some jumps because of the way they are coded. This was something that was messing up our experiment very badly. The professor in charge of the experiment was very pissed and in quite big trouble, because no one could get the data we were supposed to get. One day, at the end of the second session of my group, he came and said “I need somebody to fix this stage, I need someone to understand what’s happening and correct for it” and I thought: “I’m gonna try!”. I had nothing to lose – and so we spent probably about a month and a half of only working on this specific problem, trying different approaches. It was mainly coding and also data-taking in the lab, and in the end we reached a calibration for this system together. From there onwards, I realized I’d done research. There was something that didn’t work, and then I was the only one in the year who had obtained a really nice spectrum of the mercury lines. I’d worked with this professor, he’d entrusted me responsibilities and after that he offered me a UROP. It’s how I realized this is what I wanted to do. I also realized I liked labs, and the process of finding answers in the labs, so I switched from Theory back to normal Physics.
Then I went quite smoothly onto my third year, where I also took project-heavy topics and onto fourth year. I had a few more UROPs – this sort of research approach was very natural to me. Even if my exam results did not point me towards a PhD, my experience and project based approach did, so once I had the offer I didn’t hesitate.
What is your PhD project on? How is it related to the topics you were involved with in your undergrad?
It’s quite interesting because the turning point in my undergraduate degree was very optics-related, and related to the calibration of a detector and now I’m also involved in optics and calibration but with a different purpose. Currently I’m working on neutrino Physics. We are building a water Cherenkov detector at CERN. It is essentially a big cylindrical tank of water onto which we shoot particles. We actually don’t shoot neutrinos (that’s some of our colleagues doing it) – my team and I are instead looking at other particles called pions which are basically a background particle in the studies performed in neutrino detectors. Indeed, when neutrinos interact, they can produce pions which mess up our signal, because we can misinterpret them as other particles. We need to understand this pion background better if we are to reach the Physics goals that these larger neutrino detectors have set out for themselves.
The experiment I am working on, called WCTE, is actually very small: by very small I mean a cylinder of 4×4 metres in height and diameter. What I’m working on at the moment is the calibration of our subdetectors, these are called photomultiplier tubes. You can think of them as basically a big bulb that detects photons. It sends out a signal which is proportional to the number of photons it receives. We have 1900 of them in our detector and we need to make sure they all talk to each other properly. We need to check that they read the right amount of charge, that they are on the same clock, etc… In order to do that before the detector is built, I’m working with simulations. I’m simulating photons travelling through my tank and checking what my detector reads out and how I can make them communicate with one another.
So summing up, I’ve gone from a tiny linear stage, shooting photons at it to understanding its motion; to now working on a large scale detector with thousands or subdetectors whose behaviours I have to understand.
These projects are related on the surface, but they’re also related through the High Energy Physics group, the group I’m part of now and the group the professor I worked with on Interferometry is involved in. He offered me a Masters’ Project on the Higgs Boson, which was what I worked on during my fourth year. This was much more machine-learning oriented and coding based. It was a bit too far away from Physics for me and it’s why I went back to something that was more of a mixture, something that I could actually explain to someone.
How have your experiences been different as a woman in Physics?
It’s something that I’ve talked about with women around me. I’ve realised that as a woman, there were some things that were a bit complicated, but I’m not a woman of colour or a woman of the LGBTQ+ community, which is something that is even harder. Just comparing my experiences with those of another woman who did her undergrad at Imperial in my year, she has suffered much more from misogyny than I have. That’s something that I wanted to put into perspective.
I think the first time that this question struck me was when I read the recommendation letter that a professor wrote for me to help me apply for a PhD. In this letter, he said “I think she’s the best candidate for this role”, and the first time I read it, I thought that was weird – I’d never heard the sentence “she’s the best” before. In every paper, website, conversation, it was always like, “he’s the best”, “this man is the best candidate”, and I realised I had internalized misogyny, such that I was not even expecting parity in terms of praises. That was scary…
It’s a topic that has been going around in my department quite a lot: how do we get more women in positions in the department? Especially in higher-up positions? There is almost parity at the PhD level, but at the postdoc level it drops and above that, it is less than a handful…
What would be your advice for your undergrad/early postgrad self?
That’s something that I’ve been thinking about. I have two major pieces of advice…
The first one I have, which is very personal and outside of Physics in the sense that it works for anyone, is to write. Write about how you feel, try and unwind your emotions. The undergrad course at Imperial goes very fast and you can always find yourself postponing regular check-ups on yourself, how you’re feeling mentally and physically, and not taking the time to care about yourself. My way of doing it is writing; for some people it’s yoga, for some people it’s sleeping or hanging out with friends. Take the time to put yourself as a priority, because very often I’ve been working until I was drained, and it takes some time to come back to an uptrend. As you regularly monitor yourself (every day I ask myself, how close am I to a local low?), it helps to take a step back when you’re seeing it coming. And if you can’t step back in time, at least you know where your down mood is coming from.
The other thing I would like to share, which is much more focused on Imperial (undergrad and postgrad!) is my way of fighting impostor syndrome. This is something everybody has, just one example: a week ago I was at CERN I met this person for the first time and I swear, within the first five minutes of conversation they mentioned their imposter syndrome. Sadly it is very common in research and in Physics. My answer to that is: the people who put you here are smarter than you, by definition, as they have worked in this field for years (if not decades). Therefore if you doubt yourself and the fact that you belong here then you must be doubting them. But we just said they are objectively in a better position than you to make this call, so please stop thinking that you don’t belong here. It’s irrational!