W.Murray PPD 1 At Scientist at RAL Bill Murray RAL, CCLRC Science Week Wood Farm Primary School ● Who am I? ● Studying the very small ● The ATLAS experiment

W.Murray PPD 2 RAL My office A34 to Oxford: 10 miles Diamond light source ISIS Neutron source

W.Murray PPD 3 What goes on at RAL? Largest science Lab in UK: ISIS: Neutron source Use to probe matter: Superconductors, Coffee... Lasers Highest intensity civil laser; new states of matter High-performance computing GRID computing, 1000 CPU farms.. Diamond X-ray source Starts Next year: Study cells, reactions Space Science Largest dept in Europe; e.g. Test Beagle 2 Particle Physics My dept....

W.Murray PPD 4 Beagle II Beagle 2 was sent to Mars to look for life. At RAL we had to check it would survive the journey and work on the Martian surface Here somone tests it

W.Murray PPD 5 Launch! Launch from Baikonur in Kazakstan

W.Murray PPD 6 But where is it now?

W.Murray PPD 7 How did I get here? At School in Edinburgh 1970 to I hated writing essays... So I did maths, physics and more maths at A level Then to Oxford to read physics (1984) Followed by a particle physics Ph. D. in Cambridge (1987)

W.Murray PPD 8 Looking at the very small Each blue tick means 1000 times smaller m femto-metre 1m/1000,000, 000,000, m atometre 1m/1000,0 00,000,000,000,000 1m metre m millimetre 1m/ m micrometre 1m/1000, m nano- metre 1/1000,000, m pico-metre 1m/1000,000, 000,000, ?

W.Murray PPD 9 Another way of looking at it.... This is a journey back in time To the beginning of the Universe.

W.Murray PPD 10 How long is a light wave? High energy low energy The shorter the wave- length, the more energy the light caries High energy (short) light is used to see smaller things. Or use something else small Volunteer

W.Murray PPD 11 How to look inside an atom? We can now 'see' atoms – more than 100 types are known These are nickel: But how do we know about things inside? To look inside, we need something smaller than an atom...

W.Murray PPD 12 How do they help? Rutherford found a nucleus in the atom by firing particles at gold and watching what happened Volunteer

W.Murray PPD 13 What did this show? Positive charge at small, heavy nucleus Electrons, negative charge, moving all around

W.Murray PPD 14 Look more carefully Positive protons in nucleus Neutral neutrons in nucleus Electrons, negative charge, moving on orbits A little solar system!

W.Murray PPD 15 Forces on electrons In a REAL solar system, gravity keeps planets in orbit Isaac Newton saw that! In an atom it is the electric attraction of the protons and electrons Which is stronger? One proton said to the other: “I'm in love with that electron. I feel very attracted to her.” The other proton: “Are you sure?” “Yes – I'm positive” Volunteer

W.Murray PPD 16 How big are protons? The atom was tiny: 10,000,000,000 in a line stretch 1metre Protons are 100,000 times smaller. Now we know the proton is made of “quarks” 'Rutherford Scattering' of high-energy electrons found them Is there anything inside them?

W.Murray PPD 17 ATLAS: My experiment What is ATLAS? A very large multi-purpose facility Where is it Geneva What will it study? Proton-proton collisions What is it looking for New discoveries, e.g. The Higgs Boson How does ATLAS work? Many layers of ‘nested’ components Measure debris from collisions A flower with many petals

Where is ATLAS? © Photo CERN CERN Genev a Airport ATLAS LHC

W.Murray PPD 19 The LHC 27km vacuum pipe 8.3Tesla bending magnets, 3 o above absolute zero (He-I/He-II) © Photo CERN

W.Murray PPD 20 LHC construction under way Building the largest machine in the world takes time.. The biggest job is the 1230 magnets, each 14m long, which will bend the protons round the ring. Ready June

W.Murray PPD 21 What is it looking for? The unknown! we don’t know what we will find. But we do know we must find something... Our model of the world says quarks should weigh nothing We expect LHC to tells us what we got wrong

W.Murray PPD 22 How does ATLAS work? Note the people

W.Murray PPD 23 Inner Detector These components track the particles as they bend in a magnetic field UK works on ‘SCT’ detectors

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W.Murray PPD 25 The Semi-Conductor tracker 4 barrels 1 is a UK task Each has ~600 detector modules mounted The detectors were built here at RAL

W.Murray PPD 26 The Semi-Conductor tracker The last barrel being inserted into the other three at CERN The set of four are now being tested before final installation

W.Murray PPD 27 An ‘SCT’ module 12cm by 6cm 1536 readout strips 12 chips read at 40MHz Built with minimum mass Precise to a few μm

W.Murray PPD 28 What will it face? This is a simulated proton-proton collision A single event can look complicated We will have to face 23 at once.

W.Murray PPD 29 The End? Next few years are very exciting will we learn what mass is? Or something we didn’t expect? ATLAS is going on a voyage of discovery into uncharted regions. All we can say for sure is they won’t stay uncharted for much longer. No one knows the answers