1. Introduction to CERN
F. Hahn / CERN PH-DT1
10. May 2007

2. A short history of CERN 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.
: 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-DT1
10. May 2007

3. CERN in 2007
490ha F, 112ha CH
20 member states: A, B, BU, CH, CK, D, DK, E, F, GB, GR, H, I, N, NL, PL, P,S, SF, SK.
F. Hahn / CERN PH-DT1
10. May 2007

4. CERN a European Institute ?
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-DT1
10. May 2007

5. What is CERN ?
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-DT1
10. May 2007

6. A few Numbers: Personnel: Scientific Users: 6775 Cost: Staff: 2635
dont:
74 Research physicist
957 applied physicist / engineers
898 technicians
474 clerks and administrative
233 hand workers
Autres: 443
Fellows: 246
Scientific Associates: 397
Scientific Users: 6775
Distributed over 520 institutes and universities
Belonging to 80 nationalities
Cost:
Annual budget: 1240 MCHF (2006)
Electrical consumption: GWh/année
F. Hahn / CERN PH-DT1
10. May 2007

7. The Building Blocks of Matter
F. Hahn / CERN PH-DT1
10. May 2007

8. The “Standard Model”
F. Hahn / CERN PH-DT1
10. May 2007

9. Four Interactions (Forces)
Gravitation:
Attraction between two masses
Planetary Forces
Electro-magnetic interaction:
Cohesion des atoms
Electricity, magnetism, chemistry
Strong Force:
Nuclear forces
Origin of nuclear energy
Weak Force:
disintegration of neutron
F. Hahn / CERN PH-DT1
10. May 2007

10. How to study Elementary Particles
Elementary Particles are extremely small,
to see them one needs special tools
One needs accelerators, huge machines able to speed up particles to very high energies before colliding them into other particles.
Around the points where the particle collisions occur, scientists build detectors which allow them to observe and study the collisions.
Computer power
F. Hahn / CERN PH-DT1
10. May 2007

11. The Tools Detectors Accelerators Computers F. Hahn / CERN PH-DT1
10. May 2007

12. Accelerators (1) Basic Components:
A vacuum chamber surrounded by a long sequence of vacuum pumps,
Radio-frequency cavities produce pulsed electric fields that accelerate charged particles
Magnets:
Dipole magnets are used to divert the beam onto a curved orbit
Quadropole magnets are to focus the beam (like a lens)
F. Hahn / CERN PH-DT1
10. May 2007

13. Accélérateurs [2]
F. Hahn / CERN PH-DT1
10. May 2007

14. CERN’s machines
F. Hahn / CERN PH-DT1
10. May 2007

15. 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-DT1
10. May 2007

16. ALICE Detector
F. Hahn / CERN PH-DT1
10. May 2007

17. Computers Theory computations, simulations , ...
Controls for accelerator and detectors
Data analysis
F. Hahn / CERN PH-DT1
10. May 2007

18. Data Recording and Analysis
Example: ATLAS
Expected raw data written to tape:
200 events/sec = 320Mbytes/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)
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-DT1
10. May 2007

19. CERN at the leading edge of Technology
CERN works in close collaboration with industries
Examples: (non-exhaustive list)
Superconductivity
Cancer therapy, medical and industrial imaging radiation processing
Electronics
Measuring instruments,
the WWW
F. Hahn / CERN PH-DT1
10. May 2007