Category Archives: Blog

On Call for the ATLAS experiment

This weekend I was on call for the @atlasexperiment, specifically for our control room shifts monitoring the Inner Detector.

What does that mean?

It means I left my weekend free to be called if someone who was scheduled to be on shift during this time gets sick, injured, or is otherwise unavailable. It wasn’t likely that I’d be called, but it’s important to know someone qualified is free if needed.

On Saturday, I went to our control room to check how everything was going, and to pick up the phone I can be called on. Since it was a beautiful and sunny day, I went for a walk around our Globe of Science and Innovation here at CERN.

By the Globe, is this statue, covered in equations, diagrams and the names of historical scientists whose work has been influential to the research taking place at CERN.

This area is open to walk around on weekdays and on Saturdays at the weekend. So next time you’re in Geneva, Switzerland, why not come and check it out! And if you plan ahead, you can also book a tour of CERN!

The Great North Run and Mermaids

I am thrilled to announce that in September, I will be running the Great North Run for Mermaids!

Me running the Paris Marathon. This is the best photo of me running I have. Thanks Julien Villa-Massone! (Note: image has been edited to remove the logo on the t-shirt).

Every young person deserves to grow up in an environment where they can be their true selves. I am supporting Mermaids because of the vital work they do to make this a reality for young gender-diverse people in the UK.

Unfortunately there is a large hate campaign against the trans and non-binary community and this can only be increasing the anxiety that young gender-diverse people are experiencing. Let’s be a light shining through that hate and show that we are here for them.

To help persuade you to part with your hard-earned cash, I will be live-streaming during some of my training runs later in the year to talk about how the training is going, why I’m running for Mermaids & some science facts too!

You can check out my fundraising page, here:

Shaking off the dust

Hello! It’s been a while. I let this website slip and stopped posting and honestly I don’t remember why. However, the longer it had been since I’d last posted the more I felt like I needed to have something especially good to post when I came back.

But as they say, perfection is the enemy of good. So, instead, I’m shaking off the dust. I’ll try to get back to posting regularly and we’ll see how that goes. A lot has changed since I was posting last. And a lot is still the same. Looking forward to sharing it with you.

Bye for now! Clara

A beautiful hotel courtyard in Puebla, Mexico. Photo: C. Nellist 2019

The trial and error of time-lapse videos

As an experimental scientist my job is all about trial and error. I take measurements that no one has ever taken before, so I don’t know the results in advance. Although I usually have an idea (or hope) what the outcome will be, sometimes we can be surprised. To get the results, I start by trying one approach and, if it doesn’t go well, I learn from that and make improvements for the next time. This is the basis of the scientific method.

Screen Shot 2016-06-24 at 16.52.27

So when I decided I wanted to take more time-lapse videos, naturally for me I took the same approach. In this post, I’m going to show you some of the mistakes I’ve made along the way. Just as it is at during my research, these errors are valuable learning experiences and also part of the fun!


For information, the videos have all been made with a Go Pro 4 Black. I’ve added to my equipment along the way, usually as a result of learning from a video.

Note: All links in the main body of this post are to Amazon and are affiliated links. If you’d prefer non-affiliated, you can click the links at the bottom of the post.

#1 Securely attaching the camera

My camera was pretty new when I was volunteering for the TEDxCERN event in 2015, so I was keen to find out what I could do with it! I thought it would be a nice idea to film the guests arriving for the start. I didn’t have a lot of extra equipment, except for a 3-way tripod, so I ended up using scotch tape to to secure the tripod to a bar just above head-height. Unfortunately, it wasn’t secure enough and when I came back to check on the camera after some time, it was pointing towards the ground!

#2 Having a long enough battery life

I quickly learnt on my trip to Asia that the camera only had a battery life of ~2 hours and so leaving it on overnight wasn’t going to give me that sunrise video I was after! The problem with the standard Go Pro case is that it doesn’t have any access for the power cable, so the camera can’t be charged while it’s in the case and on a tripod. I looked, while I was travelling, for a skeleton case that would give access to this port, but I wasn’t able to find one in any shop (even at airports). Instead I had to start the camera less than two hours before the event I wanted to record.

View of the Royal Palace, Phnom Penh, Cambodia.

Later, when I returned back to Europe, I was able to find a frame which allowed me access to the charging port. Now I use this case with my portable charger, which means that I don’t need to be next to a plug to take videos. I use a 16,000 mAh external charger which, when close to fully charged near the beginning, has always been more than enough for leaving the Go Pro running overnight.

Another mistake I made with this video is setting the interval for the photo at 4 minutes, so I had very few frames to make a video from. Definitely set it to fewer. The maximum I use now is 10 seconds per photo.

#3 Keeping the camera still

During a trip to Vietnam last year, I was very fortunate to get an upgrade on my overnight boat trip in Ha Long Bay, which meant I had a private deck space! This was a great opportunity to capture a video of a sunrise in this stunning location. I setup the camera on the tripod and securely (very securely!!) tied it with shoe laces and a travel-washing line to to the railings of the boat. Around sunrise, I woke up and went outside to turn the camera on with the time-lapse setting. I then went to have breakfast on the top deck with the rest of the guests.

Later in the morning I looked back at the footage and realised something that should have been completely obvious to me – boats move. I’m not just talking about bobbing up and down in the water, although that is a problem, but they also drift with the current around the anchor and, when the crew wake up earlier than you do, they move on to their next location while all the guests are still sleeping or having breakfast. All of these movements provide a challenge when trying to have an interesting video that isn’t going to make everyone seasick! Below is what I managed to get with this. Looking back on it now, I’ve grown fond of it, but it wasn’t the video I intended to take.

Having the right equipment

I visited Japan for work in March and had the weekend before as a tourist in Tokyo. I went to visit Shibuya Crossing, which is famous for being the busiest crossing in the world! I had recently bought a rotating egg-timer like device to pan the camera as it recorded, so I was looking forward to using that. I thought it came with two screw-to-GoPro adapters, but it didn’t, so when I came to build the setup, I didn’t have all the right pieces. In the end, I taped most of it together and hoped it stayed long enough to get a good video.

When I returned, I ended up buying a 40-in-1 (37 in the US, not sure why) kit, which had the GoPro tripod adapters that I wanted, plus much more.

A tripod

The following video was taken of the Notre Dame Cathedral in Paris. Unfortuantely without a proper tripod, I had to rest the Rotating Time Lapse Timer on a step, which meant the camera was among the legs of the tourists passing by.

After this recording, I decided to buy a proper tripod. In the end I went for a Manfrotto Befree Compact Lightweight Travel Tripod, because it folds up really small and is very lightweight (it’s in the name!). 

Having a clear view (AKA cleaning the window!)

On a visit to see family in Saltburn in the UK, I stayed in a hotel room with my siblings. The view of the ocean was beautiful and I worked out that the sun would rise directly over the water! I decided to try to capture the sunrise. While I was setting up the equipment, I noticed that the window wasn’t brilliantly clean, but I couldn’t get my arm out to clean it. It didn’t seem too noticeable, so I set the camera running when I went to sleep and came back the next morning.

Unfortunately, when the sun hits at certain angles, the marks on the window show up noticeably. Take a look below.

Having an interesting video

The next time I visited Saltburn, the weather was very foggy. Feeling optimistic, I setup the camera and hoped that the fog would clear during sunset, making a dramatic video. It didn’t. Below is the result of this attempt, which I wouldn’t say was the most interesting time-lapse video.

Being aware of the weather

This lesson is linked to #1, securely attaching the camera. In this case I wanted to take a 360 degree time-lapse of Luxembourg Park in Paris. It had been sunnier in the day, but it become overcast later. I was still determined, and clouds make interesting additions to the videos. However, this also meant wind and rain.

Take 1. I set up the camera on my full-sized tripod and put this on a bench. After ten minutes or so, I turned to look at the camera and as I did I saw it suddenly coming towards me! Fortunately I caught the tripod as it fell from the bench, but because of the wind, I had to move it to the ground. This meant I didn’t get as good of a view over everyone’s head, but it was better than the camera landing on mine!

Take 2. I started the camera again. After another roughly ten minutes a sudden downpour started and I quickly thew the tripod case over the camera to protect it. But this was the end of that take!

Take 3. Since it was getting late in the afternoon and I wanted to eat at some point, I had to abandon my plan of a full 360 degree video and instead settle on a ~150 degree video. This time the wind was not too strong and the rain (mostly!) held off, so I got the video I wanted. You can see I also edited the colour on the final video to give contrast to the clouds and bring out the colour of the senate building.


So that’s where I’m up to now. I’m sure there will be many more lessons to learn as I go along. Perhaps even enough for a second post. The next thing I want to work on is getting rid of glare and reflections from windows when I have to film in doors. For that I’m going to try a dark cloth taped around the camera.

For now, I’ll leave you with a video I took in Cambodia at an elephant sanctuary of the elephants taking their morning bath. Enjoy!

If you want to check out all my videos, you can visit my YouTube Channel. If you like them, please give them a thumbs up and maybe even subscribe. Thanks!

Non-affiliated links (all link to the UK Amazon store):

Sept, 2019: This post was edited to remove the affiliated links because I no longer use that service.

Test Beams

The last ten days or so I’ve spent at CERN testing new designs of pixel detectors for the ATLAS experiment. Since it was the IOP’s #iamaphysicist event on the same day we were setting up, I tweeted out the following picture.

To measure our pixel detectors, we need a beam of particles from a particle accelerator. Fortunately at CERN, we have many to chose from! Just see the diagram of all of the accelerators required to get the protons to the LHC. Our experiment uses the SPS, or Super Proton Synchrotron, the last accelerator in the chain of accelerators which feed the LHC with protons. The protons enter the SPS at 25 GeV and are accelerated up to 450 GeV (note the LHC accelerates to 7500 GeV, or 7.5 TeV, per beam). We then use a target to change the type of particle from a proton to a pion.

The LHC is the last ring (dark grey line) in a complex chain of particle accelerators. The smaller machines are used in a chain to help boost the particles to their final energies and provide beams to a whole set of smaller experiments, which also aim to uncover the mysteries of the Universe.

Continue reading Test Beams

An average day

I have a new flatmate now who has a keen interest in science. The other day when I came home he asked (in French) “What did you do today?”. It’s a simple question. Although it doesn’t always have a short answer as I also knew that he also wanted to understand, what do I do on a day-to-day basis as a scientist? This question is the inspiration of today’s post, which is a diary of my day.


Last night I was invited to the wine and cheese social event at a workshop taking place at my lab, which was a great chance to see a friend and former Manchester colleague who was attending the workshop, and also to meet new people in ATLAS who were outside of my analysis group (ATLAS is ~4000 people, so it’s not unusual that I haven’t met them all!). The conversation developed into some very interesting debates and I ended up staying later than I had planned. Hence this morning’s early start was a difficult one. I have an hour’s commute to get into work so on the way I grabbed a pain au chocolate at the train station (as I didn’t have time to eat breakfast at home) and spent the time on the train proof-reading the thesis of a PhD student I work with.


The first meeting of the day started at 8.30am. This was exceptional and was arranged to fit with the schedule of someone in Australia. For them the meeting was at 6.30pm, so it was just about reasonable for both sides. I am one of two contact people for a part of our analysis, which means I keep up-to-date with what everyone is doing and report back to the conveners of our analysis to make sure everything is on track. This is my first leadership position in ATLAS analysis and I learn a lot about how to do the job well every day. It’s useful to have these meetings to get advice and support from my superiors.

The second meeting, starting at 9am, continued on the same topic, but involved everyone from the analysis. We had presentations from studies that had taken place over the last week and discussed the results. It’s a long meeting, as there are many steps of the analysis to go over in detail. Continue reading An average day

ATLAS in New York

This post is a quick one as I’m currently on holiday in New York. Today we went to visit the Rockefeller Centre and nearby is a statue that looks very familiar to me. The bronze statue is of a male figure, the Titan Atlas, holding up the sky. The reason it is so familiar to me is because my collaboration at CERN is called ATLAS and our logo is based on this statue (although it’s recently gone through re-design to make the figure more androgynous). Below you can see the previous version of our logo, and the newer design that we use now.


The previous ATLAS logo (above) and the new one (below).


Since I was there, I couldn’t resist have a photo taken with the statue. I like to add as many photos and images as possible* into my presentations and so I’m sure this will be useful. Here’s the photo!


In the nearby LEGO shop, there is a LEGO version of this statue. We already have LEGO version of our detector, both in a large version (shown below with Prof. Higgs), and in smaller versions. If you would like to see the small version as part of a LHC LEGO set, you should head over to the LEGO IDEAS page where you can vote for it!

I should head off now, there’s a lot more sight-seeing to do!

(*Much to the strain of the upload server when it comes to adding my presentation to the online agenda.)