Presented for
Arnulfo Zepeda On behalf of the Mexican Collaboration
Sep. 2000
PHYSICS AND ASTROPHYSICS OF ULTRA HIGH ENERGY COSMIC
RAYS
BUAP CINVESTAV UMSNH UNAM
Material selected and prepared for Rebeca López
GOAL
• To develop physics and astrophysics of ultra high energy cosmic rays through the participation of Mexican scientists in the construction of the Pierre Auger Observatory.
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CONTENTS
• Antecedents on cosmic rays.
• The Pierre Auger Observatory.
• The Mexican Participation (this proposal).
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ANTECEDENTS Some major discoveries made with cosmic
rays
• The positron (the first antimatter sample), 1933.
• Extended air showers, 1938.
• The muon (first relative of the electron), 1943.
• The pion (the carrier of nuclear interactions, postulated by Yukawa), 1947.
• Particles with strangeness, 1947.
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Technics for detection of cosmic rays
COSMIC RAY FLUX
• Cosmic rays are produced in explosive astrophysical events.
• The low and medium energy spectrum is reasonable weel understood.
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The complete diffuse background radiation over the
spectral region 10-9-1020 eV.
ULTRA HIGH ENERGY COSMIC RAYS
• Cosmic rays may be produced with ultra high energy in exotic sources.
• They may be further accelerated in strong magnetic fields and plasma shock waves.
• Then they travel in the interstellar medium, which is never empty.
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Possible sources of high energy
cosmic rays
Possible sources of high energy
cosmic rays
XZ Tauri
HH 30
ULTRA HIGH ENERGY COSMIC RAYS
• The interstellar medium is filled with low density radiation, the cosmic microwave background radiation, which originated during the early live of the Universe, at the time of the formation of atoms, at about 400,000 years after its birth.
• Cosmic rays interact with the CMBR and if their energy is high enough, then their energy materializes into matter, pions are produced with high probability. Thus high energy cosmic rays loose soon their energy.
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N u c l e i + ( M B R )
N 1 + N 2 + p ’ s + n ’ s + ’ s
l t l o s s e s a b o u t 2 n u c l e o n s p e r M p c
F o r E 1 0 E e V o n l y p r o t o n s s h o u l d b ec o n s i d e r e d
P r o t o n s
I f E 0 . 5 E e Vp + p + e + e -
I f E 5 0 E e V = 0 . 5 x 1 0 2 0 e V p +
pn
G Z K c u t o f f
G r e i s e n – Z a t s e p i n - K u z ’ m i n ( 1 9 6 6 )H i l l + S c h r a m m ( 1 9 8 5 )L u i s A n c h o r d o q u i + D o v a + E p e l e + S w a i n ( 1 9 9 7 )
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _n ’ s , + ’ s ’ s ° 2 + e + e -
E 1 0 1 4 e V
PROCESSES ON THE CMBR
THE GZK CUTOFF
• There is a limit, at around 5 X 1019 eV to the energy with which cosmic rays may arrive to the Earth from far away (50 Megaparsecs)
This is the GZK cutoff.
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AGASA Energy Spectrum
Implications of events beyond the GZK cutoff
• Suggest the existence of exotic sources?
- Quasi-stable massive particles.
- Supersymmetric matter.
- Topological defects.
• Violation of Lorentz invariance?
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EXPOSURES OF UHECR DETECTORS
. Km2 sr year
1020 N(1020) Expected
Volcano Ranch -60 1 0.34(1962)
Haverah Park 270 4 1.6(1987)
Fly’s Eye 167 0 1.0(stereo)
Fly’s Eye (mono) -600 1 2.4(1993)-------------------------------------------------------------------------------------
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EXPOSURES OF UHECR DETECTORS
.Km2 sr year
1020 N(1020) Expected
AGASA 1223 7 7.0(1999)
Yakutsk 933 4 5.4(1999 – reanalysis)
HiRes 1090 7 6.3(1999)
Pierre Auger 14000 60
24 events 1020 eV
Rate = 0.6 km-2 sr -1 century -1 R. LópezR. López
PIERRE AUGEROBSERVATORY
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The shower
MAIN OBJECTIVE OF THE PIERRE AUGER
OBSERVATORY
• To understand the origin and nature of the ultra high energy cosmic rays, one of the major mysteries of modern physics.
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GOALS OF THE PIERRE AUGER OBSERVATORY
• Detect a good number of ultra high energy events.
• Measure with precision the energy of the primary cosmic particle.
• Determine the incoming direction.
• Identify the nature, type of particle.
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Consequences of the Pierre Auger
Observatory data
• In astrophysics.
• In the theory of elementary particles.
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Hybrid Detector
How water Cherenkov detectors work
SCHEME OF THE FLUORESCENCE
DETECTOR
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SIMULATION
• The computer simulation of
- The shower
- The detectors
- The electronics
• Shows that the designed observatory will fulfill its objectives.
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#S
#S
Sites of the Pierre Auger Observatory
Auger Observatory Exposure
Sky as seen by observatories, 60° max shower zenith angle.
North --> red, South --> green.
Pampa Amarilla Site
• On March 17th 1999 work at the site in Mendoza began. Construction will continue till 2003 although observations will begin by 2001
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The first water Cherenkov detector in Malargue
Plan of a Fluorescence
Detector Building.
Los Leones
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Construction of the Central Station
Building.
International Collaboration Metting
Cost and contributions
• The total cost of both observatories is 100 million dollars.
Approved:
Argentina
CNEA 10,000
Mendoza 5,000
Brazil 2,000
France 2,300
Germany 5,500
Mexico 300
Slovenia 500
UK 1,000
US 9,000
35,600
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Cost and contributions
• Pending approval:Australia 600
Bolivia 30
China 1,000
Greece 200
Italy 3,200
Mexico 2,650
Poland 50
------
7,730
TOTAL 43.300
The rest of the countries in the collaboration are about to submit their applications.
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Schedule
• Construction of Southern Observatory
Start: March 1999
End: end of 2003
First face: Engineering Array:
40 WCDs and 2 FDs
Communication network
Data collection system
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Schedule
End construction:
end of 2001
Start taking data:
January 2002
Construction of Northern Observatory
Start: 2003
End: 2005
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Finance Board
• Agreement for the Organization, Management and Funding of the Pierre Auger Observatory
• Among Science Founding Agencies of Countries in the Pierre Auger Collaboration
• Signed at Mendoza, Argentina, March 16, 1999.
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THE MEXICAN GROUP
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Participants
Institution Researcher Technicians Students
BUAP 10 1 17
Cinvestav 6 1 4
UMSNH 3 2
UNAM 4 2
23 4 23
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Specific goals
of the Mexican grup
• Tecnological Development.
• Research activities.
• Involve the national industry.
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Fuorescence Detector
• Design of optical system (special recognition by the project management).
• Electronics.
• Development of a tester for mirror quality.
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Surface Detector
• Water Purity.
• Reflective properties.
• Methods of calibration and monitoring.
• Requirements for local trigger.
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Surface Detector
• Design and construction of the container and of the liner: local
• development and international coordination (by the task leader).
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Surface Detector
• Design and development of the central triggering system and of the data acquisition system.
• Installation of first tanks.
• Installation and operation of the array of surface detectors.
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Rotoplas
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Computer simulation
- Atmospheric shower.
- Response of the detectors.
- Reconstruction of data.
- Test of high energy hadronic interaction models.
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Students who have finished their thesis
Degree Institution
631
BachelorMasterPh. D.
BUAP
1 Ph. D. CINVESTAV
2 Bachelor UMSNH
13
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Students working on their thesis
Degree Institution
451
BachelorMasterPh. D.
BUAP
5 Ph. D. CINVESTAV
11
BachelorPh. D. UMSNH
17
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Students to graduate between 2001 and 2004
YEAR BACHELOR MASTER Ph. D.
2000 3 2 2
2001 4 2 3
2002 4 3 1
2003 4 3 3
2004 4 3 3
19 13 12
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BUDGET FOR THE MEXICAN PROGRAM
in thousands of US dollars.
• R and D (travel, computers, prototype components)
1996 .... 35
1999 .... 60
2000 .... 42 (Cinvestav)
2000 ....130 (BUAP)
2001-4...328 THIS PROPOSAL
• Observatory components
2000 .... 300 (BUAP)
2001-4..2650 THIS PROPOSAL
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