April Cridland and Alberto Jesus Uribe Jimenez
Dr April Cridland (Physics 2012) and Dr Alberto Jesús Uribe Jiménez (Physics 2016) are both post-doctoral researchers working at CERN in the ALPHA collaboration – an international research team working on the ALPHA-g experiment with the aim of performing the first-ever precision measurement of the weight of antimatter. The team has already been highly successful in trapping anti-hydrogen, the antimatter counterpart of hydrogen, and studying its properties through spectroscopy.
April and Alberto in front of the Antimatter Factory at CERN, where antimatter is generated. It is home to all collaborative experiments involving antimatter, including ALPHA
April's story
At school, April tried (unsuccessfully) to get her physics teacher to run a field trip to CERN in the year that they first started the Large Hadron Collider (LHC). Following an undergraduate degree at the Open University, she came to Sussex for her Masters, which then led to her PhD. She also met her future husband at Sussex, and together they have a son for whom CERN is like home. April works at Swansea University and joined the ALPHA team in 2018.
Alberto's story
Alberto studied at Universidad de Granada before coming to Sussex for his PhD, where he was particularly attracted by the pioneering advances in ion (Penning) trap technology conceived and developed at Sussex. He works with Canada's particle accelerator centre TRIUMF and joined the ALPHA team in 2021.
April and Alberto were both part of the international team responsible for making a in September 2023.
What made you choose Sussex for your PhD?
April: I completed my undergraduate degree with the Open University and my practical laboratory courses were held at Sussex in the summer, where I got to see how beautiful the campus was and how it was perfectly triangulated between the Downs, the city and the sea. When it came to choosing a university for an MSc, Sussex was at the forefront of my mind.
Alberto: Sussex is a well-recognised institution, and the physics department has several groups working in the ion trapping field. I was particularly interested in the work of the Geonium Chip group with Dr José Verdú, and I wanted to learn more about this technology.
It was a very attractive environment to study for a PhD and Brighton is a very young city with a lot of activities – the perfect city to live in as a student.
What do you like about working at CERN, Geneva?
April: The game-changing opportunity that CERN offers is to work with people at the top of their field. If I need to design and manufacture a very custom part for our experiment, I can wander into one of the workshops and discuss my ideas with experts who are enthusiastic to work with me to solve the problem. They love it when you bring them something that has a new challenging aspect.
Alberto: Having access to some of the most advanced technology and being in touch with a lot of experts in the field from all around the world is something that I could not have imagined a few years ago.
April with the Penning trap she built in 2024 for the ALPHA-g experiement. Alberto also worked on this trap
Can you tell us which breakthrough in your field you’d most like to see?
Alberto and April: There are some explanations in our understanding of physics that are missing. Of course, as researchers in this field, we would like to see as many of these mysteries solved as possible.
In our experiment, we study asymmetries between antimatter and matter, which could shed light on why antimatter is not present in the universe in similar amounts as matter. We know that right after the Big Bang, the universe was composed of matter and antimatter in equal amounts, but it is obvious that it is not the case anymore. How matter became dominant is one of the most important mysteries of physics nowadays. And, of course, we would like to know the answer!
Alongside your technical expertise, which skills do you draw upon most when working in a multilingual, multicultural environment?
April: Teamwork is an essential part of working in scientific collaborations, which, in ALPHA, means working in small groups on particular pieces of hardware, participating in data-taking shifts around the clock and showing up to an ‘all hands’ call to clean the experimental zone.
Researchers in ALPHA also speak at least 10 different languages, so, for most people, English is their second or even third language. It is therefore crucial to have patience, take time to understand the people you are working with and have a sense of humour when inevitable misunderstandings occur at the end of a long night shift.
Alberto: Technical expertise is important, but many other things need to be considered: social skills, being open-minded and being able to accept different people. I think these are skills that could be useful anywhere, and I learned many of them at Sussex, where there is also a rich multicultural environment.
After this long, hard process, it is extremely rewarding to get results and answers to questions that no one could answer before."Dr Alberto Jesús Uribe Jiménez
Have either of you had a mentor, or been a mentor, and if so, what have you gained from the experience?
April: In addition to supervising students to guide them through their projects, I have also taken part as a mentor in the Women in Tech mentoring scheme at CERN. I’ve gained a lot of confidence from the experience, and it's always inspiring to hear someone else’s passion for their field. It is rewarding to see them becoming more self-assured, follow their own ideas and then share their discoveries.
Alberto: I have supervised several graduate and undergraduate students both at Sussex and ALPHA. While doing it, there is always something to gain on the technical side and learning how to share knowledge with people. On a more personal aspect, being in contact with some new, enthusiastic people is refreshing and motivating.
What do you find most enjoyable about your job?
April: I currently lead the team that builds the Penning traps for ALPHA (the inner-most part of the experiment, which controls all the charged antimatter particles), and I enjoy taking responsibility for organising such a complex and meticulous project. It requires sourcing very specialised items from around the world, designing new pieces of equipment and liaising with multiple workshops at CERN.
I also enjoy running the experiment and seeing new ideas come to fruition. Nothing beats watching anti-hydrogen atoms annihilate in real time!
Alberto: Research is an exciting job, and finding new answers is the most interesting part. In the beginning, when a new search is started, it is often difficult to understand the context, and then there are long hours of work to understand the concepts until we know enough to start creating something new. As experimental researchers, a large part of our time is invested in designing and building new machines.
After this long, hard process, it is extremely rewarding to get results and answers to questions that no one could answer before.
Alberto at CERN, standing next to the ALPHA-g experiment which is used to measure antimatter gravity
What part of the Sussex experience has helped you most? Do you have any standout Sussex memories?
April: I was in my office at Sussex at the end of my PhD when I received the call that I was being offered the job with ALPHA and would be moving to Geneva in a few months. It was the knowledge and experience that I gained in Dr José Verdú’s research group at Sussex that allowed me to secure the position, and the time spent working as part of a small team on a new experiment was invaluable.
My biggest standout memory from Sussex is meeting my future husband, who was also studying for a Masters in the Physics Department. He works at CERN too, as a particle Physicist with the LHCb experiment. Together, we have a 12-month-old son who was born in Geneva, and for him, CERN is like home.
Alberto: Working in the Geonium Chip group in the School of Mathematical and Physical Sciences (MPS) was the best experience. I learnt so much and I enjoyed working in the lab and sharing experiences with the rest of the team and our supervisor, Dr José Verdú. Doing a PhD is hard, but it is also quite enjoyable and rewarding. It was a great time.
But studying at Sussex is a bit more than a good academic experience: living on campus and sharing such an amazing environment with people from all around the world provides you with amazing memories and friends.
You can’t change what has already happened, you can only change how you respond to it. It’s what you do next that’s important."Dr April Cridland
What's the best advice you've received and/or given?
April: You can’t change what has already happened, you can only change how you respond to it. It’s what you do next that’s important.
Alberto: Just be respectful and accept other people as they are. We are all different, we might have different backgrounds or different cultures, and that is great.
What can't you live without?
April: My son. He is an endless source of curiosity, determination and cheeky laughter.
Alberto: Cheese. And, living in Switzerland, it is not difficult to find it everywhere.
April's husband and son playing on one of the CERN dipole magnets
April, who or what inspires you most?
My colleagues inspire me the most. I often feel refreshed after talking through a problem or planning the next phase of the experiment. This is where PhD students can make the biggest impact, as they see the situation with fresh eyes and are not encumbered with the memories of the attempts that didn’t work.
Alberto, what do you do to relax?
Listen to a podcast, or a song, or read while lying on my bed. Sitting in a park can also work if it is sunny.
To learn more about April and Alberto's research, read published September 2023 in Nature.
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