50 years of the PS
Last month marked the first collisions in the largest man made particle physics experiment ever conducted, the LHC. In a remarkably short time, considering the drawbacks the experiment has suffered in the past, the LHC has gotten from very rough first collisions, to prolonged, stable beams and finishing up a few days ago with the highest energy collisions in any particle physics experiment to date.
This milestone comes just in time for the 50th birthday celebrations of another important particle accelerator; the Proton Synchrotron.
This machine was the first big circular particle accelerator at CERN, and was the beam source for such experiments as the Gargamelle bubble chamber, which first discovered neutral currents in the 70’s.
On the 3rd and 4th of this month at CERN, several Nobel Laureates arrived at CERN to reminisce about the success of the PS and the development of particle physics since. Many of the talks were focussed at discussing the experiments at the PS, SPS, LEP and then the LHC, with a few talks focussing mainly on theory.
The event was a fascinating insight into the minds of some of the greatest contributors to particle physics in the last half century. It definitely left me inspired.
As testament to the Proton Synchrotron’s success, it is still used as the second stage accelerator for the protons injected into the LHC today.
COLLISIONS!
Posted by Tom in Physics, Science, Technology on November 24th, 2009
So as you may well be aware, the LHC started up again this weekend after a good 14 months off.
September 10th last year was the date penned for the long overdue startup of the Large Hadron Collider – the worlds biggest (and best) particle accelerator. Unfortunately a problem with the cooling system caused a leak of liquid helium and a saftey mechanism called a quench kicked it. It basically ruined a few magnets so the whole thing had to be shut down to be fixed.
Well, it was fixed, and this weekend saw the grand reopening. On Friday evening, the various LHC control rooms were full of physicists and excitement as the beams were reinjected into the machine. First one way around, then the other. The plan, as us postgrads understood it, was that collisions (ie, two beams in the LHC going in opposite directions and brought to a focus at the detectors) were not due until early December.
Well, we were wrong. Today (the 23rd November), the LHC injected beam 1 into the LHC, then injected beam 2 and started ‘beam synchronization’. I don’t fully understand what that means, but I know that there was one bunch per beam (about a metre in length worth of protons), and my best guess at ‘beam synchronization’ is that the two bunches were brought close together.
Obviously the beams weren’t focussed and we weren’t running at anything close to design luminosity, but a few collisions occured in all 4 detectors. An exciting moment for everyone involved with the LHC, indeed.
The CERN Press Release of the weekend’s events and a summary of the collisions explains a bit further what the goings on were this weekend, and what the plans for the LHCs immediate future are.
The coming months should be an exciting time for particle physics, and the coming years will hopefully shed some light on the darker corners of the Standard Model and beyond…
New Recordings
New versions of Down the Rabbit Hole and Advice from a Caterpillar are now up!
Recordings of Pig and Pepper and A Mad Tea Party will be made shortly 
Feynman Diagrams that look like animals
In Particle Physics, there is a special tool that is used to help understand, visualise and calculate certain aspects of a particle interaction. This is the Feynman Diagram.
A lot of Feynman Diagrams are fairly dull, monotonous affairs, essentially consisting of two particles scattering off each other, like so:
However, there are some Feynman Diagrams which can, with the help of a little imagination, be made more exciting!
Recently, I discovered that, if I stare too long at Feynman Diagrams, I start to see the diagram in a different way, much like how you can often see faces while staring at a plastered ceiling, or see shapes in the clouds.
I see animals in Feynman Diagrams.
Here’s a few to get you started.
Now, any High Energy Physicist will tell you that this has already been done, in the form of the Penguin Diagram.
Which, if you squint a bit, can look a bit like a penguin. (The animal, not the chocolate bar)
The Penguin Diagram originated when a bet between Physicists was made, the loser of which had to include the word ‘Penguin’ in their next paper. So it’s all a bit artificial really…
Next, the deer diagram. It’s fairly self explanatory, the gluon emitted by the up quark represents the antlers, the rest follows from that…
The fish diagram. This one takes a little bit of thinking, but not too much. Obviously the top quark pair production vertex is the ‘nose’ of the fish, the bottom and anti-bottom quarks are the main fins of the fish and the quark antiquark/lepton antilepton pairs are the tail fins.
The lobster. This one, I’ll admit, is a bit contrived. But bear with me. The quark antiquark/lepton antilepton pairs at the very right are obviously the claws. Where the quark and anti-bottom lines form a diamond with the top anti top pair is the head, the gluon is the body (albeit a very skinny body considering the size of the head), and the protons at the left are the tail.
Well, it’s either a lobster or Edward Scissorhands on his side with his arms upstretched…
New/Redone songs
I just uploaded 2 more songs from the Alice in Wonderland collection.
I’ve been experimenting with open tunings recently, so these two are recorded in CGCFGE tuning, which sounds pretty nice!
I’ll also re-record a few more of the songs in CGCGAE in the coming weeks.
Have a listen!
Wow, COOL!
After the ’slight setback’ last year, that pushed the schedule back by about a year, the LHC is back to being one of the coolest places on Earth.
The magnets of the LHC, during operation, must be cooled to around 1.9 Kelvin, which is around -271.25 Celcius. COOL!
Now that the whole collider is cooled and the new quench system installed (a failsafe mechanism), the first beams can be brought back into the LHC.
At first, the energy of each proton beam will only be a fraction of their design intensity, around 450GeV.
The first collisions should happen in late November, followed by a step up in energy to a few TeV, where the next lot of collisions will happen. This is still less than half of the design intensity, but at this energy, there may still be some new physics to do. It breaks Tevatron’s record of the highest energy particle accelerator lab at least.
At the moment, it’s looking like the LHC will stay with collisions at this lower energy for quite some time, before the final push towards 7 TeV per beam.
After all, it broke once, why risk doing it again when you can get perfectly good data first!?
Another Game
I seem to get bored a lot.
When that happens I usually traipse across the internet searching for things to do.
This is one game I came across which helps to pass the time.
The Album Art Game.
Step 1. Go to Wikipedia and click the Random Article button. The title of the article will be your band name.
Step 2. Go here. The last few (<6) words of the last quote on the page will be your album title.
Step 3. Go to flickr and explore the last 7 days. The third picture is your album cover.
Now put it together in Photoshop or similar.
Here’s a few I’ve come up with.
The last one is my favourite.
Credit to original artists for their flickr pictures.
NEW STUFF
I’ve done a few new recordings.
Firstly, I rerecorded Down The Rabbit Hole. It’s slightly different. Capo 4 makes it better.
Second, I’ve recorded A Mad Tea Party. Marking chapter 7 of Alice’s Adventures in Wonderland, documenting the often fine line that can exist between two extremes. Genius and madness being the obvious example. The opening of the song is a bit sketchy, missed notes aplenty, just bear with it. Also, beware of the clipping in the chorus. My mic was up too high… I promise I’ll record this again soon!
Lastly, I wrote a new song called 100.
ANTLERS – A Note on parTicLE physics acRonymS
Since starting my PhD with the ATLAS project, I’ve learned about various acronyms used to name detectors, software, and other related projects in the particle physics community. A simple example would be LHC – Large Hadron Collider. Nothing funny going on there, it does exactly what it says on the tin. It collides hadrons (protons and lead ions in this case) and it is rather large.
Not all acronyms are quite as nice and to the point, however. I will list just a few of the more contrived ones (throughout, bold type is used to denote the letters used in the acronym).
Firstly ATLAS – A Toroidal LHC ApparatuS.
Since when did the final letters of a word count to appear in an acronym? Fair enough if you take the first two or three letters of a word, but taking the first and last letters. Come on! At least think of another word beginning with S!
Second, DEGREE – Dissemination and Exploitation of GRids in Earth sciencE.
Now we are just being stupid. Taking the last letter and not even the first letter. Of the word SCIENCE, no less.
GENIUS – Grid Enabled web eNvironment for site Independent User job Submission.
This one leaves whole words out. Important words like web and job. Which are pretty much the point of the environment. To submit jobs through the web… I can ALMOST forgive the use of ‘N for environment’, but not when you omit such crucial words!
BaBar – B-Bbar detector. Now this is just adding letters to make it sound like cartoon elephants!
Finally, ATLANTIS – ATLAS eveNT dISplay.
Do I need to say anymore?
In the world of High Energy Physics, there is definately a trend of ‘pick your acronym first’ going on. What words the represent is entirely arbitrary as long as the Acronym sounds nice. If the words have relevence to the project, it’s just a bonus.
HONOURABLE MENTIONS (for comedy value):
GIGGLE – GIGascale Global Location Engine.
LEMON – LHC Era MONitoring.
PASTA – Processors, memory, Architectures, STorage and TApes.
and for the Twin Peaks fans:
DIANE – DIstributed ANalysis Environment.
Two New Tracks
A few more quick tracks, Awaken and Night Terror. Both written as I went along, with pretty much one take on everything. More of an experiment in sound than songs as such.
Have a listen.
