talk to cern students, 13 august 2004 happy birthday cern 50 herwig schopper
TRANSCRIPT
Talk to CERN Students, 13 August 2004
Happy Birthday
CERN50
Herwig Schopper
Talk to CERN Students, 13 August 2004
Council argued that CERN should make history,not talk or write about it *
But CERN is such a unique European success (1. European organisation) that one should learn from 50 years of experience
I shall talk about
History
Successes and Failures
Talk to CERN Students, 13 August 2004
Two initiatives in parallel:
1.physicists:join European forces to be competitive with US, in particular for large facilities E.Amaldi, P.Auger, L.Kovarski, F.Perrin1950 report by Kovarski: establish intergovernmental centre, „essentially scientific“
2. Political initiative: European Movement
European Cultural Conference, Lausanne 8-12 December 1949
bring Europeans together after war
170 people from 22 countriesMinisters, senators, member of parliaments,others D. de Rougemont (Suiss Writer), R.Dautry ( F Minister), *
Foundation of CERN
Talk to CERN Students, 13 August 2004
The two initiatives combined at 5. General Conference of UNESCO in Florence, June 1950
-Rabi’s Resolution 7 June 1950 addressed to DG UNESCO could be considered as ‘conception’ of CERN (or real birth??)
At CERN 30. Anniversary 1984
Rabi’s speech: CERN peaceful compensation for building bomb
“CERN was founded less then ten years after the bomb was made. I feel that the existence of the bomb …had a large part in making CERN possible. ....Europe had been the scene of violent wars..for 200 years. Now we have something new in the founding of CERN”
“I hope that the scientists at CERN will remember that they have other duties than exploring further into particle physics. They represent the combination of centuries of investigation and study… to show the power of human spirit. So I appeal to them not to consider themselves as technicians …but .. as guardians of this flame of European unity so that Europe can help preserve the peace of the world.”
Talk to CERN Students, 13 August 2004
Agreement to constitute “Council”signed on 15 February 1952 by 11 countries Approval of Convention 1 July 1953, signed until December 1953 by 12 States
Conseil Européen pour la Recherche Nucléaire
« N » is problem
Subsequent submission of letters of ratification to UNESCO DG
Convention comes into force if ratified by at least 7 States: on 29 September 1954 (Birth!!?)
CERN became intergovernmental organisation
who knows what CERN stands for?
Talk to CERN Students, 13 August 2004
Objectives of CERN Promote science and technology (later training)
to make Europe competitive
Bring nations together first in Europe, later worldwide
CERN only lab with both objectives (now also SESAME)
CERN became first European Organisation
Expectations were met in excellent way
Talk to CERN Students, 13 August 2004
1. Choice of site : Proposals:: Geneva (CH), Copenhagen (DK), Arnhem (NL), Longjumeau (Paris)
‚…delegates had clearly been officially briefed to make stiff fight.,
scientific prestige …was clearly rated very high,…
expectation of ..appreciable .. ‘financial gain’
Final decision at 3. Council meeting at Amsterdam October 1952
Geneva: small country, neutrality, nice living conditions
Some Problems at Foundation
Difficulties forgotten today, but start was not easy
Talk to CERN Students, 13 August 2004
Proportional to income and wealth, but how to asses it?
GNP or GNP per capita?
Sweden and CH against GNP/capita (since their GNP/capita 50% higher than UK und F !)
Italy and Yugoslavia in favour
‚...endless and confused discussion..’
2. National Financial contributions
Ben Lockspeiser (Council President) exploded, fed up with
‘shameful horsedealing’
‘Offended, a Swedish Delegate broke down and wept openly’
Final solution: GNP with limit of 25 % maximum contribution
Talk to CERN Students, 13 August 2004
CERN became model for other organisations
in Europe ESO, EMBL
Joint Institute for Nuclear Research JINREstablished for Warsaw pact states in March 1956First organisation following CERN Close cooperation with CERNimportant bridge between West and East during cold warNew role after disappearance of Soviet union New Charter in 1992 Now 18 Member States
SESAME Synchrotronradiation Laboratory near Amman, JordanIntergovernmental organisation like CERN,
Estbalished by UNESCO April 2004 according to CERN model
Presently 7 Members (Bahrain, Egypt, Israel, Jordan, Palistan, Palestine, Turkey,.....Iran, Kuwait, Yemen, UAE)
Talk to CERN Students, 13 August 2004
Basic Physics using large facilities is excellent tool for ‚Science for Peace‘
Laws of physics are valid everywhere
No secrecy in basic science (neither industrial nor military)
Large facilities (accelerators, reactors, detectors, telescopes, etc) need scientific, administrative and
political cooperation (at highest level)
Cooperation creates confidence between people from different nationalities, religions, cultures, mentalities, political systems
Physicists in basic science give priority to science* instead to money Money has only secondary importance, not main motivation, profession is hobby
Talk to CERN Students, 13 August 2004
Examples of Confidence buildingCERN – IHEP (Soviet Union) agreement in 1968became model for IHEP-USA agreementand later model for USA- Soviet union agreement (Breshnev-Ford) (Mirabelle staff, 1. Strike on SU territory)
Disarmament meeting at Geneva in 1980ieswhen in deadlock private meeting (USA,USSR) at CERN unblocked it
(Trivelpiece asked for lunch)
Meeting with Ambassadors of Disarmament Conference‘Avoid collisions between countries, CERN does better’
Talk to CERN Students, 13 August 2004
Science radiates into politics
CERN-JINR,Dubna: only link East-West Germany
L3 chinese from Mainland and Taiwan
SESAME: Israel -Palestine – Iran
Help individualswho have of political, racial or religious problems Orlov (from Sowjetunion to CERN, talk to Petrosyansk) Okun (in SPC, not allowed to come, talk to Chuvilov) Hadizadeh (arrested in Iran, letter to Minister and Chatami, could come to SESAME meetings, now in USA)
Help developing countries
Talk to CERN Students, 13 August 2004
In time where relations between some nations are sometimes characterised by
hatred and violence
it is gratifying that scientists, administrators and politicians are prepared to sit around the same table to discuss scientific projects
Small light in dark times
Talk to CERN Students, 13 August 2004
LEP/LHCSPCPS/ISR
CERN crossing the Swiss-French Border
Talk to CERN Students, 13 August 2004
Memberstates of CERN
Von 12 zu 20 Mitgliedsstaaten
+ Associates USA, Russland, Japan, Indien, Israel,........
Talk to CERN Students, 13 August 2004
Working Style of CERN
Tasks shared between CERN – Users
CERN builds and operates facilities, coordinates exploitation (Technical Competence)
“Service Station”Users come from Universities, national Labs, etc. (about 6000, of which only about 80 from CERN)
(Scientific Competence, Rejuvenation)
Talk to CERN Students, 13 August 2004
Users in whole World
Talk to CERN Students, 13 August 2004
Domains of Success
Accelerators and Storage Rings
Detectors, Information Technology
Large Experimental Facilities (“Experiments”) Coordination
Scientific Results
Talk to CERN Students, 13 August 2004
Why race to higher energies and hence big facilities?
1.The smaller constituents of matter are, the stronger they are bound togetherHeisenberg uncertainty p . R ≈ h/2π„Atom smashers“
2. To produce heavy particles and new states of matter (energy concentrations like after big bang) E = m.c2
Collider Rings
Talk to CERN Students, 13 August 2004
Why are detectors so big?• Momentum measurement in magnetic field B
p . R ∞ B B limited to several Tesla, ∆R limited to 10 to 100 micron=> R must be order of meter for p of several GeV
• ‘Calorimeter’ must contain particle shower of several Radiation length for hadron showers λ about 0.5 m ( ∞ log Energy) => calorimeter length more than a meter
But also precision in determining coordinates!!!!
Talk to CERN Students, 13 August 2004
Accelerators: First Period of CERN: ‚Copy‘
Machine with highest energy in Europe, ‚copy‘ of BNL machine
Proton-Synchrotron PS Protons 28 GeV (circumference 200 m), Main objective at foundation of CERN,
Start of operation 1959, workhorse for many years In operation still today, pre-accelerator for all other machines
Talk to CERN Students, 13 August 2004
John Adams with Vodka-Bottle from JINR
to empty when PS more than 10 GeV
PS reached 24 GeV on 24 November 1959
Talk to CERN Students, 13 August 2004
Second Period of CERN: Unique Facility
ISR Intersecting Storage Rings Proton-Proton Speicherring
„Collider“
Two deformed Magnet - Rings, cross in 8 points,
Counter-rotating Proton beams with 31 GeV (up to 60 A).
Talk to CERN Students, 13 August 2004
Layout of ISR
Talk to CERN Students, 13 August 2004
Fixed Target <=> ColliderAdvantage of Colliders:Car driver knows the effect of head –on collisions
- Useful Energy is Center of Mass EnergyES = 2 x Ekin (kinetic Energy Ekin)
ISR ES = 62 GeV
Particle hitting target at rest ES ~√Ekin
ISR equivalent Energy 2000 GeV!
- Storing beams increases probability of collisions
Disadvantage of Colliders:-No secondary beams of other particles
Talk to CERN Students, 13 August 2004
ISR Intersecting Storage RingsMany Records in the art of accelerator building
Storage time of several weeksonce Antiprotons stored for 1000 hours New limit for lifetime of antimatter
New window für physics
ISR was unique in World, (no successor up to now, only LHC)
1984 difficult and painful decision to stop it, ( to find ressources for LEP)
Talk to CERN Students, 13 August 2004
Next step:Super-Proton-Synchrotron SPS
Proton-Accelerator Energy 400 GeV
To be able to compete with American Fermilab 1000 Magnets in Tunnel with about 7 km circumference
Failed almost since new sites were proposed in 12 states,but no agreement
Solution CERN I und CERN II , 2 DGs only 1981 full unification of lab
-started operation 1976Important Extension of Site to France
Talk to CERN Students, 13 August 2004
John Adams and Willibald Jentschke in SPS Tunnel 1973
Talk to CERN Students, 13 August 2004
Super-Proton Synchrotron SPS
Powerful secondary beams
two new experimental areas, West and Nord (in France)Muon-, Pion-, Neutrino – beamsPolarised beams and Targets
Heavy- Ion Acceleration AU- nucleiInvestigate Quark – Gluon Plasma (first observation ?) *
SPS still in operation for fixed target Physics and pre-accelerator for (LEP)/LHC
Talk to CERN Students, 13 August 2004
Period of Matter – Antimatter Colliders
Protons – Antiprotons in SPS ring 2 x 400 GeV
SPPS (third mode of operation of SPS) (proposal Rubbia) ES = 800 GeVEquivalent energy 155 000 GeV , Even today not realisable!
ButAntiprotons difficult to produce‚stochastic cooling‘to homogenise direction and energy(against Liouville‘s Theorem)Maxwell‘s Dämon ?
Simon van der Meer (Nobelpreis 1983)
Particles – Antiparticles in same Ring
Talk to CERN Students, 13 August 2004
Disadvantage: complicated events
Advantage: Protons easy to acceleratelimited by magnet field strength and radius
Protons not elementary, contain 3 Quarks + Gluonen
e+ e- collider
Advantage: give clean events, high event rates e+ and e- have no inner structure
p – p collider
Quarks
Gluons
Disadvantage: acceleration of electrons very difficult in ring synchrotron radiation losses ~ E4/R
Talk to CERN Students, 13 August 2004
LEP Large Electron – Positron Collider
Proposal by international community in 70‘ties :
Elektron-Positron Collider with 50 to 100 GeV per beam(after succes of ADONE, PEP, DORIS, PETRA, TRISTAN)Look for W and Z, Supersymmetry, top.
cost optimisation gives R ~ E2
=> circumference about 30 km
?Ring or two colliding lineacs? LEP last circular e+e- facility
Such a facility only realisable as World Machine?Could be built at CERN?
Talk to CERN Students, 13 August 2004
LEP ApprovalVarious proposals with „oscillating“ energy and radius in the late 1970iesCERN-Council accepts new LEP Design in June 1981Tunnel with circumference of 27 km
Conditions: constant budget (low level) (resign !?) ‚stripped down LEP’ minimum of components at start Phases
LEP 1 2x 50 GeV LEP 2 2x 100 GeV 3. LHC (Tunnelcircumference) Workshop March 1984
Lausanne Time is contingency (indeed one year delay) stop many existing facilities even when still interesting
Groundbreaking 1983 Start up 1989 End 2000
Talk to CERN Students, 13 August 2004
CERN Budget
Talk to CERN Students, 13 August 2004
LEP Positions
Top secret
Talk to CERN Students, 13 August 2004
Water in LEP Tunnel
Talk to CERN Students, 13 August 2004
Mrs.Thatcher at CERN 1983
Talk to CERN Students, 13 August 2004
Paul Johannes II at CERN
Talk to CERN Students, 13 August 2004
Talk to CERN Students, 13 August 2004
LEP Groundbreaking 1983
Presidents Aubert (CH) and Mitterand (F)
Talk to CERN Students, 13 August 2004
LEP ConstructionConventional machine ??new Technologies (examples)
oabout 3000 bending magnets (iron sheets with concrete in between), mass quality control, installation
o highfrequency accelerating cavities, first copper, later superconducting Nb
onew Getter-Pumps, extreme highvacuum in 27 kmosurvey procedures (Laser, Satellites) for installation of
magnets and other components (Tolerance tenths of mm for distances up to 10 km )
Not size of tunnel impressive, But size combined with precision. Toleranz circumference = ± 2.8 cm, measured 0.8 cm
Talk to CERN Students, 13 August 2004
LEP Tides
Talk to CERN Students, 13 August 2004
LEP Tunnel
Talk to CERN Students, 13 August 2004
LEP Operation
LEP 1: beam energy around 50 GeV for 7 years „Z- Factory“ millions of Z- particles produced (UA1 und UA2 had only handful events for discovery)
LEP 2: from 1996 energy increase in steps with SC cavities (Nb massiv and coated)During last months of 2000 achieved 104.5 GeV/beam Energy concentration as 10-10 s after Big Bang of cosmos
During 11 years LEP worked excellently
Last circular e+e- machine => NLC
Talk to CERN Students, 13 August 2004
Detectors, Data Handling
Bubble chambers Gargamelle, BEBC,... Develop technology of superconducting magnets
Multiwire chambers (G. Charpak Nobelpreis)many applications, customs
„Calorimeter“ Sampling Total-Absorptionscounter STAC, energy measurement without magnetic field, neutral particles *
Crystal counters for Gamma, 10000 cristals (application in medicine)
Silicon-Strip Detectors a few Precision
Data handling:Collection, reduction, storage, analysis, transfer
WWW developed for LEP - Experiments
Talk to CERN Students, 13 August 2004
Large „Experiments“
Not „Experiment“, project in itselfManagement success to organise themInstitutions on their own: several hundered scientists, administrators,...Components from many Labs in many countries(coordination, fitting together, time schedule)Industry like, but international, no management power!
Modell for scientific, technical and financial cooperation („resource committees“)
„LEP Model“ continued with LHC experiments
1000 to 2000 scientists
Talk to CERN Students, 13 August 2004
LEP ExperimentsALEPH,ALEPH, DELPHI,DELPHI, L3L3 und und OPAL OPAL *International collaborations with hundreds of scientists from countries with different political systems, various traditions, mentalities and religions
Components fabricated in many countries
Cost of each detector 100 to 500 millionen CHF
Hundered to several hundered scientists
Talk to CERN Students, 13 August 2004
CMS
ATLAS
ALICE
LHCB
coin
Talk to CERN Students, 13 August 2004
Scientific Success
Progress in Science by:
1. Spectacular Discoveries
2. Tedious work in detail
3. Missed opportunities
All equally important!
Talk to CERN Students, 13 August 2004
Some (most important?) questions of Particle Physics
1.Elementary building blocks of Matter?Quarks, Leptons (charged, Neutrinos) Supersymmetric particles, other ?What determines Masses?
2.Which Forces in nature and their properties?Carrier: Photon, Gluon, W, Z (‚heavy Light‘), graviton
Great Unification of Forces ?
Talk to CERN Students, 13 August 2004
Periodic Systematics of Elementary Particles
Charges: Electrical: +2/3 -1/3 0 -1 Weak : flavour in columns Strong : colour
Strong force No Strong force
Talk to CERN Students, 13 August 2004
Vector Bosons (Spin 1)Carrier of Forces by exchange
Interaction Boson Discovery
Electromagnetic Photon Photoeffect
no charge Compton effectStrong Gluon DESY
1976colour
Weak W+, W- Z CERN
1983weakcharge
Photons do not interact
Gluons interactW and Z interact
Talk to CERN Students, 13 August 2004
New Paradigma• Since Democritos, Galilei, Newton:
External building blocks with forces between them explain phenomena in natureOnly building blocks changed during last 300 years(molecules, atoms, nuclei, protons and neutrons, quarks and leptons)
Eternal change by different arrangements of blocks
• Present most fundamental recognition:Symmetries and their (spontaneous) breaking are basis of understanding of NatureNo undestructible building blocks (Newton)
From Democritos to Plato?
Talk to CERN Students, 13 August 2004
Spectacular Successes of CERN
Large transvers momenta at ISR 1972
Indication of partons inside nucleon
Neutral currents (Z) of weak interaction Gargamelle 1973 (Lagarigue)
W and Z with SPPS, UA1 und UA2 1983 (Rubbia, van der Meer)
Gluon discovered at DESY
Talk to CERN Students, 13 August 2004
Pion Production with large transverse momenta at ISR
Indication of pointlike partons
Talk to CERN Students, 13 August 2004
Gargamelle Heavy Liquid Chamber
Filled with 16 tons of
Freon
Talk to CERN Students, 13 August 2004
Neutral Currents
Gargamelle 1973
Elastic Scattering+ e + e
Elektron Bremsstrahlung-cascade
Talk to CERN Students, 13 August 2004
UA 1 Detektor
„Hermetic“ Detector
Talk to CERN Students, 13 August 2004
UA1 Z e- + e+
Talk to CERN Students, 13 August 2004
Z – event in OPAL at LEP
Talk to CERN Students, 13 August 2004
Discovery of W and Z Press Conference 1983
visa
Talk to CERN Students, 13 August 2004
‚Work in detail‘
Impossible to mention here all relevant results of CERN
Nucleon-Structure (with polarisation)
Neutrino –Scattering (except neutral currents)
CP-Violation (LEAR)
K and B Oscillations
Quark-Gluon –Plasma
Exotice Atoms and nuclei, Anti-hydrogen
g –2 of Muon
Talk to CERN Students, 13 August 2004
Missed Opportunities
Second Neutrino PS 1961 BNL
J/ at ISR 1972 1974 BNL,SLAC
at ISR 1972 FermiLab 1977
Experience, hard work and perseverance do not suffice
A little bit of luck is also needed !!
Talk to CERN Students, 13 August 2004
LEP ResultsNo Sensations (TOP, SUSY, Higgs)
But fundamental results from detailed work
Weak Interactions• Precision measurements
turned HEP into Precision Physics (< 0.5 %)
• Standard-Modell is renormalisable Fieldtheorie Radiation corrections (cp. Lambshift) (TOP - Quark),
• 3 Kinds of Neutrinos
• Coupling W-Z-Z
Talk to CERN Students, 13 August 2004
Linenwidth and Hight give No. of Neutrino kinds
(Nν = 2.985 ± 0.008)
Position of Maximum
gives
Talk to CERN Students, 13 August 2004
Standard Model with
Precision < 1%
confirmed
Talk to CERN Students, 13 August 2004
Existence of coupling
between W-Z
Talk to CERN Students, 13 August 2004
Strong and other Interactions
1. 3- and 4 – Jet Physics Quark-Physics , Gluon -Gluon – coupling
2. Running coupling constant S (Quark –Confinement Asymptotic freedom)
3. Limit for Higgs-Mass (discovery with LHC)
4. Indication for Supersymmetry Gand Unification ?
Talk to CERN Students, 13 August 2004
Talk to CERN Students, 13 August 2004
Talk to CERN Students, 13 August 2004
Talk to CERN Students, 13 August 2004
LEPmortHS
LEP Fest October 2000
Talk to CERN Students, 13 August 2004
The Secret of Success scientific quality and competence count
(no „by-in“)
no national or other quota for employment of personel or adjudication of industrial contracts (no „just retour“)
no secrecy, cooperation in spite of competition
no discrimination of nationality, race, origin, religion *
ambition to be at frontier of world excellence, in spite of high risks
Memberstates in favour of pragmatic solutions avoiding purely political aspects
Talk to CERN Students, 13 August 2004
Future of CERNGuaranted with LHC Fundamental discoveries likely and needed for HEP
CERN excellent Laboratoryavoid bureaucratisation, too little staff
Many difficulties not surprisingsimilar as with LEPe.g. bell shaped spending profile with constant
Finances will not be end of HEP, but long time scales are worrisome!!
Interest of young scientists !!!
Talk to CERN Students, 13 August 2004