Tag Archives: pixel detectors

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.

cernaccelerators
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.

7am

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.

8.30am

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 Blog – Notes from Underground: Pixel Prototypes

The ATLAS Blog is currently focusing on the work that takes place when the LHC is not colliding protons for the experiments. The series is called “Notes from Underground”. This week’s post is from me and focuses on the work of developing new pixel detectors for upgrading ATLAS, specifically the IBL. You can read it here:

http://atlas.ch/blog/?p=2163

I obviously recommend checking out the other posts in the series too!

Successful installation of the ATLAS Insertable B-Layer

On the 8th of May, I had some fantastic news in my inbox: the IBL, or Insertable B-Layer, had been taken 100m underground and installed into the ATLAS experiment at CERN! Unless you’re an ATLAS physicist yourself, you probably don’t know what I’m talking about when I mention the IBL. In short, it’s an extra layer of pixel detectors which has gone into the very centre of the ATLAS detector ready for data taking when we switch back on next year. This extra layer is there to cope with the upgrade of the Large Hadron Collider (LHC) accelerator to a higher energy by being faster, more accurate (the pixels are smaller) and better able to withstand the more intense radiation background. Working on prototypes of pixel detectors for the IBL, specifically on a new technology called 3D silicon pixel sensors, was the focus of my PhD with the University of Manchester and it’s brilliant that it has been successfully installed!

Installation of the Insertable B-Layer into the ATLAS detector. Photo credit Heinz Pernegger.
Installation of the Insertable B-Layer into the ATLAS detector. Photo credit Heinz Pernegger.