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Prof. Marcelo A. Leigui de Oliveira
CCNH – UFABC
Física de Astropartículas – as propriedades e técnicas de detecção dos
Raios Cósmicos de Ultra-Alta Energia.
Universidade Federal de Santa Catarina,
Florianópolis, SC
14 de setembro de 2012
Artistic view of a cosmic rays shower.
Credit: ASPERA/Novapix/L.Bret
• More than 100,000 cosmic rays will hit each of you during this
lecture
What are Cosmic Rays? Cosmic Rays (CR) are high-energy particles of extraterrestrial
origin
Secondary CR (produced by the primaries in the
Earth’s atmosphere) consist of essentially all
elementary particles and nuclei (both stable and
unstable). The most important are
• nucleons, nuclei & nucleides,
• (hard) gammas,
• mesons (p±,p0,K±, …, D±,…),
• charged leptons (e±, m±, t±),
• neutrinos & antineutrinos (ne, nm, nt).
“Classical” CR are nuclei or ionized atoms ranging from a
single proton up to an iron nucleus and beyond, but
being mostly
protons (~90%) and particles (~9%).
Including stable and quasistable particles:
• neutrons,
• antiprotons & (maybe) antinuclei,
• hard gamma rays (l < 10-12 cm),
• electrons & positrons,
• neutrinos & antineutrinos,
• esoteric particles (WIMPs, magnetic monopoles,
mini black holes,...)?
A short history of cosmic ray physics
• 1900 C.T.R. Wilson noticed that electroscopes lose their charges
even if they were very well isolated from the neighbouring sources;
• 1900 C.T.R. Wilson noticed that electroscopes lose their charges
even if they were very well isolated from the neighbouring sources;
• 1900 C.T.R. Wilson noticed that electroscopes lose their charges
even if they were very well isolated from the neighbouring sources;
• 1900 C.T.R. Wilson noticed that electroscopes lose their charges
even if they were very well isolated from the neighbouring sources;
• E. Rutherford hypothesised that most of the ionisation was
due to natural radioactivity;
but much more penetrating than natural radioactivity!
• 1910 T. Wulf who developed the best electrometers of that time, measured a
fall from 22,25 ions/cm3 s (~ sea level) to 15,7 ions/cm3 s, at the top of the Eiffel
Tower (330 m asl) but they should have halved in 80 m;
Victor F. Hess after one of his successful flights in 1912.
•1912 Hess ascended in his balloon to 5 km (in an open ballon without
oxygen!) and measured unambiguously an increase in ionisation (4 times
more discharges at 4880 m): there must be a radiation of cosmic origin
ionizing the atmosphere;
1936 Hess &
Anderson
• 1931 Auguste Piccard took off from Augsburg with a pressurized cabin
to reach a record altitude of 15,785 m. During this flight, Piccard was
able to gather substantial data on the upper atmosphere, as well as
measure cosmic rays. In 1932, launched from Zürich to made a second
record-breaking ascent to 16,200 m. He ultimately made a total of
twenty-seven balloon flights setting a final record of 23,000 m.
• 1931 Auguste Piccard took off from Augsburg with a pressurized cabin
to reach a record altitude of 15,785 m. During this flight, Piccard was
able to gather substantial data on the upper atmosphere, as well as
measure cosmic rays. In 1932, launched from Zürich to made a second
record-breaking ascent to 16,200 m. He ultimately made a total of
twenty-seven balloon flights setting a final record of 23,000 m.
• 1936 G. Pfotzer used three-fold coincidences of GM tubes to measure
intensities up to 28 km
• 1948 J.A. Van Allen used single GM tube aboard a V-2 rocket to
measure intensities up to 161 km.
Back in 1938:
1 eV = 1,6 x 10-19 J ↔ 1J = 6,25 x 1018 eV
1 x 1020 eV = 16 J
Some EAS arrays:
• Volcano Ranch, USA (1959-1962);
• Haverah Park, UK (1968-1987);
• SUGAR, Australia (1968-1979);
• Yakutsk, Russia (1969 -1990);
• Akeno, Japan (1980 ++);
• AGASA, Japan (1986 ++ );
• EASTOP , Italy (1989-1999);
• CASA/MIA, USA (1990 ++);
• Kascade, Germany (1995 ++);
• Pierre Auger Observatory, Argentina (2001++).
1994 The AGASA Group in Japan and
the Yakutsk group in Russia each
reported an event with an energy of
2x1020 eV.
Pierre Auger Observatory: taking data
since 2004
Other measurement techniques
Fluorescence and Cherenkov Lights
Emission Propagation
Air Fluorescence Detector
Detection
Cherenkov Light
)(/
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Cherenkov Radiation in the Atmosphere
Some air Cherenkov experiments:
• CANGAROO, Australia (1992++);
• CAT, France (1996++);
• CLUE, Canary Islands (1997 - 2000);
• HAGAR Telescope(s), India (2005++);
• HEGRA, Canary Islands (1992-2002);
• HESS, Namibia (HESS-I 2002, HESS-II
2012);
• MAGIC, Canary Islands (2003++);
• VERITAS, USA (2007++);
• CTA project.
HESS I and HESS-II: four 12 m
telescopes and one 28 m telescope
MAGIC: a 17 m telescope VERITAS: four 12 m telescopes
Cherenkov Radiation in the Atmosphere
Cherenkov Radiation in the Atmosphere
Air Fluorescence
AIRFLY Collaboration, Astroparticle Physics, Volume 28, Issue 1, September
2007, Pages 41-57,
Measured fluorescence spectrum in dry air at 800 hPa and 293 K
F Arqueros, F Blanco and J Rosado, New
J. Phys. 11 (2009) 065011
Some air fluorescence experiments:
• Fly’s eye/Hires, USA (1981/1999 ++);
• Pierre Auger Observatory, Argentina (2001++);
• ASHRA, Hawaii (2002++);
• Telescope Array (TA), USA (2006++);
• EUSO, ISS (2016) 1991 The Fly's Eye cosmic ray
research group in the USA observed a
cosmic ray event with an energy of
3x1020 eV.
The Telescope Array The Pierre Auger Fluorescence Detector
FD: 24 (+3) fluorescence
telescopes (30° x 30° FOV):
Fluorescence track reconstruction
- monocular mode
- stereo mode
issues:
- atmospheric transmission
- fluorescence yield
- Cherenkov subtraction
• Horizontal attenuation
monitors (range ~ 60 km)
• Steerable LIDARs
• Laser Shots (Central Laser
Facility): light scattering
• Infrared Monitors (clouds)
•Cross-checks
FD: 24 (+3) fluorescence
telescopes (30° x 30° FOV):
• longitudinal development
2tan 0
0ip
ic
RTt
The Shower Detector Plane
Cherenkov subtraction
FD: 24 (+3) fluorescence
telescopes (30° x 30° FOV):
• longitudinal development
Cherenkov subtraction
Gaisser-Hillas
fit
FD: 24 (+3) fluorescence
telescopes (30° x 30° FOV):
• longitudinal development
Cherenkov subtraction
Gaisser-Hillas
fit Energy
FD: 24 (+3) fluorescence
telescopes (30° x 30° FOV):
• longitudinal development
Cherenkov subtraction
Gaisser-Hillas
fit Energy
FD: 24 (+3) fluorescence
telescopes (30° x 30° FOV):
• longitudinal development
•10% duty cycle
• almost calorimetric measurement
20 May 2007 E ~ 1019 eV
1.1/
)(04.0)(01.008.1
10)(12.0)(06.049.1
2
17
38
ndf
syststatb
eVsyststata
aSE b
FD
S38 (1000) vs. E(FD)
661 hybrid events
J. Abraham et al, Phys. Rev. Lett. 101, (2008)
061101.
hybrid SD only FD only
Angular
resolution
0.6° 1-2° 3-5°
Aperture independent of
E, mass, models
independent of
E, mass, models
dependent of E,
mass, models
and spectral
slope
Energy independent of
mass, models
dependent of
mass, models
independent of
mass, models
Molecular Bremsstrahlung
1. EAS particles dissipates energy through ionization
2. A weakly ionized plasma is formed at T ~ 104 K
3. This plasma cools down very fast (10 ns) though collisions with air
molecules
4. Bremsstrahlung from free electrons (f ~ GHz: microwave band)
Coherent Radio Emission
1. EAS produces e± in the shower front
(2-3 m thick)
2. These e± bend in the geomagnetic field
(~ 0.3 G), generating synchrotron
radiation (geosynchrotron)
3. Emissions for all e± add up coherently
4. The radiation can be detected by
antennas at f ~ 100 MHz (FM band)
RESULTS FROM PIERRE AUGER OBSERVATORY
CMB:
A. A. Penzias and R. Wilson, Astroph. J., 142 (1965) 419
K. Greisen, Phys. Rev. Lett., 16 (1966) 748
G. T. Zatsepin, V. A. Kuz'min, Pis'ma Zh. Eksp. Theor. Fiz. 4
(1966) 53
The GZK Cutoff
Science (Nov/2007)
(a) Photon shower (b) Proton shower (c) Iron shower
And what about the climate changes?
And what about the climate changes?
And what about the climate changes?
Muons telescope
Water Cherenkov Tank
Water Cherenkov Tank
Light pollution in Brazil:
Prof. Marcelo A. Leigui de Oliveira
CCNH – UFABC
Obrigado!
Universidade Federal de Santa Catarina,
Florianópolis, SC
14 de setembro de 2012
Prof. Marcelo A. Leigui de Oliveira
CCNH – UFABC
Backup Slides
Universidade Federal de Santa Catarina,
Florianópolis, SC
14 de setembro de 2012
Chemical composition of the atmosphere
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Mass Thickness & Depth
Atmospheric layers
1. Troposphere*: 0 – (7 – 18) km
2. Stratosphere*: 18 – 50 km
3. Mesosphere: 50 – 80 km
4. Thermosphere: 80 – 480 km
5. Exosphere: > 480 km
* most important for CRs physics
Chemical composition of the atmosphere (without water), per volume
ppmv: parts per million by volume
Gas Volume
Nitrogen (N2) 780.840 ppmv (78,084%)
Oxygen (O2) 209.460 ppmv (20,946%)
Argon (Ar) 9.340 ppmv (0,9340%)
Carbon dioxide (CO2) 390 ppmv (0,0390%)
Neon (Ne) 18,18 ppmv (0,001818%)
Helium (He) 5,24 ppmv (0,000524%)
Methane (CH4) 1,79 ppmv (0,000179%)
Krypton (Kr) 1,14 ppmv (0,000114%)
Hydrogen (H2) 0,55 ppmv (0,000055%)
Nitrous oxide (N2O) 0,3 ppmv (0,00003%)
Carbon monoxide (CO) 0,1 ppmv (0,00001%)
Xenon (Xe) 0,09 ppmv (9x10−6%)
Ozone (O3) 0,0 a 0,07 ppmv (0% a 7x10−6%)
Nitrogen dioxyde (NO2) 0,02 ppmv (2x10−6%)
Iodine (I) 0,01 ppmv (10−6%)
Ammonia (NH3) Traces
Gases not included (dry air):
Water vapor (H2O)
~0.40% throughout the atmosphere,
usually between 1%-4% in the
surface
From Wikipedia
Chemical composition of the atmosphere
Electromagnetic waves:
• oscillating electric and magnetic fields that travel in vacuum
in the speed of light: c = 299.792.458 m/s ≈ 3 × 108 m/s
• the electromagnetic spectrum is continuous and we distinguish
different types of waves based on bands of frequency or wavelength
• within each band different processes may
occur, leading to different opacities to the
waves
Radiation Balance on Earth
Electromagnetic Processes
Pair production
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