Introduction to CERN F Hahn CERN PHDT 1

Introduction to CERN F. Hahn / CERN PH-DT 1 10. May 2007 1

A short history of CERN n n n End of the 40’s: “Brain drain” towards the USA December 1949: Louis de Broglie proposes the creation of a European science laboratory. 1952: First Provisional “Conseil Européen pour la Recherche Nucléaire” Geneva site is selected. 29. 9. 1954: Organisation Européenne pour la Recherche Nucléaire 12 Member-states: B, CH, D, DK, F, GB, GR, I, N, NL, S, YU 40 ha in Meyrin (CH, GE) Building the first two machines: SC and PS F. Hahn / CERN PH-DT 1 10. May 2007 2

CERN in 2007 n 490 ha F, 112 ha CH n F. Hahn / CERN PH-DT 1 10. May 2007 20 member states: A, B, BU, CH, CK, D, DK, E, F, GB, GR, H, I, N, NL, P, S, SF, SK. 3

CERN a European Institute ? n n n Particles research requires large installation for Accelerators and Detectors. Even the largest European countries could not afford to build a national laboratory for particle physics, that would have similar resources than CERN Today each country spends a small fraction of their gross national for CERN, allowing them to participate in the world’s most advanced physics experiments F. Hahn / CERN PH-DT 1 10. May 2007 4

What is CERN ? n n n CERN is a laboratory where scientists unite to study the building blocks of matter and the forces that hold them together. CERN exists primarily to provide scientists from Europe (and all the world) with the necessary tools. These are accelerators, which accelerate particles to almost the speed of light and detectors to make the particles visible. F. Hahn / CERN PH-DT 1 10. May 2007 5

A few Numbers: n Personnel: Staff: dont: n n n n 2635 74 Research physicist 957 applied physicist / engineers 898 technicians 474 clerks and administrative 233 hand workers n Scientific Users: 6775 n n n Cost: n Autres: 443 n n Fellows: 246 Scientific Associates: 397 F. Hahn / CERN PH-DT 1 10. May 2007 Distributed over 520 institutes and universities Belonging to 80 nationalities n Annual budget: 1240 MCHF (2006) Electrical consumption: 700 GWh/année 6

The Building Blocks of Matter F. Hahn / CERN PH-DT 1 10. May 2007 7

The “Standard Model” F. Hahn / CERN PH-DT 1 10. May 2007 8

Four Interactions (Forces) n Gravitation: n n n Electro-magnetic interaction: n n n Cohesion des atoms Electricity, magnetism, chemistry Strong Force: n Nuclear forces Origin of nuclear energy n disintegration of neutron n n Attraction between two masses Planetary Forces Weak Force: F. Hahn / CERN PH-DT 1 10. May 2007 9

How to study Elementary Particles are extremely small, to see them one needs special tools 1. One needs accelerators, huge machines able to speed up particles to very high energies before colliding them into other particles. 2. Around the points where the particle collisions occur, scientists build detectors which allow them to observe and study the collisions. 3. Computer power F. Hahn / CERN PH-DT 1 10. May 2007 10

Detectors The Tools Accelerators Computers F. Hahn / CERN PH-DT 1 10. May 2007 11

Accelerators (1) Basic Components: A vacuum chamber surrounded by a long sequence of vacuum pumps, n Radio-frequency cavities produce pulsed electric fields that accelerate charged particles n Magnets: n Dipole magnets are used to divert the beam onto a curved orbit n Quadropole magnets are to focus the beam (like a F. Hahn / CERN PH-DT 1 lens) 10. May 2007 12 n

Accélérateurs [2] F. Hahn / CERN PH-DT 1 10. May 2007 13

CERN’s machines F. Hahn / CERN PH-DT 1 10. May 2007 14

n n n Detectors Based on the principle of the interaction between charged particles and matter Identification of the resulting particles Measurement of their energy F. Hahn / CERN PH-DT 1 10. May 2007 15

ALICE Detector F. Hahn / CERN PH-DT 1 10. May 2007 16

n n n Computers Theory computations, simulations , . . . Controls for accelerator and detectors Data analysis F. Hahn / CERN PH-DT 1 10. May 2007 17

Data Recording and Analysis Example: ATLAS n Expected raw data written to tape: n n n 200 events/sec = 320 Mbytes/sec ( equivalent to 1 CD every 2 seconds, so 1’ 800 CD’s / hour That would make 7 km of CD stapled /year Data Analysis will be world Wide (GRID) n Data will be exported from CERN to 10 computing centres with a rate of 10 Gbytes/sec. After processing data are distributed to 50 collaborating institutes. F. Hahn / CERN PH-DT 1 10. May 2007 18

CERN at the leading edge of Technology CERN works in close collaboration with industries n Examples: (non-exhaustive list) Superconductivity n Cancer therapy, medical and industrial imaging radiation processing n Electronics n Measuring instruments, n the WWW n F. Hahn / CERN PH-DT 1 10. May 2007 19