Things beginning with P

I occasionally get asked, since the LHC is not currently providing collisions, what we’re actually doing now. Answers include Protons, Papers, Poppadoms, Preparation, Python, Pictures and Philip Pullman.


There is a lot of work going on on the accelerators, including a new linear accelerator (LINAC4), a key part of the journey the protons make from a little bottle of hydrogen to the highest energy beam ever produced. LINAC4 has been completed and is now being tested – see here for a report on the current status.

But that’s the accelerator physicists, what about the rest of us?

There are several upgrades to the detectors and the software also going on. To pick one almost at random (because I saw a progress report on it this week), some of my collaborators are working to make the ATLAS reconstruction software thread safe. Reconstruction software is the code we use to turn the signals from the detector into intelligible physics objects such as energies, particles, jets and so on. It is a huge project – if you are keen you can browse the C++ source code on gitlab. To date, the code has basically been “parallelised” by running many instances over many different computers, each reconstructing a single collision event. But the way computer architectures are developing, to exploit them properly we need the reconstruction of a single event to be able to split into several processes while sharing common data and other variables in a controlled way, and we need multiple events to be processed in flight. This is a major redesign and a lot of work. I’m not directly involved (I seem to be writing mostly Python these days, not C++) but it seems to be going well.

I am involved in writing physics papers on the data we have already recorded, and there are lots of these coming out. Some of them so unprecedented it appears a new twitter account was required.

(If you really to keep up to date, my experiment has a twitter feed here, and there is a CMS one here.)

Akbar's naans

Akbar’s naans

Such things have taken me this week to CERN, where is now snow on the Jura (see above), and Manchester, where there are massive naans (Right. There were also poppadoms, not shown, which alliterated better.)

I’m now preparing lectures on Fourier analysis and special relativity, as I will be teaching second year UCL undergraduates about those, starting next week.

Finally…  I’ve started watching the BBC production of Philip Pullman’s “His Dark Materials”. Very good so far. It has just been pointed out to me that Chris Wormell, who drew the maps for my last book, is the illustrator for Pullmans’ latest, The Book of Dust series. I knew Chris was good but now I feel even more fortunate that he agreed to draw physics from out of my head.






About Jon Butterworth

UCL Physics prof, works on LHC, writes (books, Cosmic Shambles and elsewhere). Citizen of England, UK, Europe & Nowhere, apparently.
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