THE NALTA PROJECT

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THE NALTA PROJECT A NORTH AMERICAN NETWORK OF
SPARSE VERY LARGE AREA AIR SHOWER ARRAYS A
research project that involves students
(high-school, undergraduate graduate),
teachers and Universities in North
America James Pinfold University of Alberta
James Pinfold Prague June 2004

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• The cosmic ray energy spectrum
• The GZK limit and Ultra High Energy Cosmic Rays
• Detecting cosmic rays Extended air showers
  (EAS)
• Cosmic ray experiments around the world a brief
  look
• Tantalizing hints of a non-random component of
  high energy cosmic rays
• Sparse very large area EAS array network
• Sparse very large area educational arrays
• NALTA
• The ALTA network , an example
• The proposed EEE array in Italy
• Closing remarks

James Pinfold Prague June 2004

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A list of Fundamental Questions

• How is the HECR spectrum made up?
• What is the dominant source for CR below the
  knee?
• What is the origin of the knee of the CR
  spectrum?
• What is the origin of particles above the knee?
• At what energy are the fluxes of galactic
  extra-galactic cosmic rays are equal?
• What are the sources of extra galactic rays?
• What is happening at the GZK cut-off around the
  ankle?
• What is the nature of the exotic (centauro, etc.)
  events observed largely at high altitudes?
• Is there any evidence of non-random component of
  cosmic rays (large area coincidences, bursts,
  sources, etc)

James Pinfold Prague June 2004

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The Energy Range

• High energy cosmic rays consist of protons,
  nuclei, gammas,
• Measured flux extends to
  s1/2 400 TeV
• Highest energy particles are extremely rare
• Supernova shock fronts can accelerate particles
  upto 1015 eV
• Above 1015 eV, presumably acceleration is in
  AGNs (?)
• How do UHECR protons evade the GZK cut-off at 7
  x 1019 eV (if source is gt100Mps away)?

1/m2/s
Knee
1/m2/year
GZK Cut-off
Ankle
1/km2/year
James Pinfold Prague June 2004

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Mysteries of the Spectrum

• Protons are trapped in our Galaxy (mG B-fields)
  up to 1017 - 1018eV
• Protons can travel straight above 1020eV
• Supernova shockwave acceleration up to 1015 eV
• Above the knee the acceleration mechanism is
  essentially unknown AGNs, massive black holes
  systems, gamma ray bursts ?

1018 eV
GZK land
1020 eV
James Pinfold Prague June 2004

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Acceleration of CRs above the Knee

• Up to the knee Fermi acceleration (FA) in
  supernova shock fronts can explain the
  spectrum
  Emax RSNR x Z x B x bsh
• This can be used to constrain the size and
  magnetic field requirement if acceleration
  mechanism is 1st order FA.
• Only AGNs and GRBs have sufficient R x B to be
  candidate acceleration sites
• However, we have a lack of candidate sites for
  energies above 1020 eV.

The HILLAS Plot
James Pinfold Prague June 2004

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The Mysteries of an Opaque Universe

• The universe is opaque to UHECR
• In the case of the GZK cut-off a 5x1019 eV
  proton has a mfp of 50 mpc due to interaction
  with photons in the the CMB.
• But no nearby sources have been identified,
• How are the protons with energy gt EGZK
  getting to us? There are two
  scenarios
• BOTTOM UP acceleration in AGNs, gamma rays
  bursters, etc. then production of a neutral (n,
  so,..?).
• BOTTOM UP with GZK cut-off relaxed by violation
  of Lorentz Invariance, etc.
• Or TOP DOWN topological defects (cosmic strings,
  monopoles, etc.) or massive relics, etc.

Region restricted by GZK cut-off 100 Mpc
10,000Mpc
Size of observable universe
James Pinfold Prague June 2004

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Life Above the GZK Cut-off?
Many events observed Above the GZK cut-off AGASA
(EAS ground Array) seems to violate The GZK
cut-off HI-RES (atmospheric. fluorescence )
seems to obey GZK theory However both expts see
events with E gt 1020eV Some debate as to
possible sources Some 6 doublets and 1 triplet
of events have been seen within 2o cones
Flys Eye Big event 3 x 1020eV (50J!)
HI-Res. AGASA
200 billion particles
?
UHECRs as of 2001
HiRes vs. AGASA
GZK
(4?10)x1019eV gt 1020 eV
James Pinfold Prague June 2004

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Extended Air Showers
15 km
1016eV
Particle density at ground level
100m
Ne Nm correlation
Particles/m2
There are many ways of detecting cosmic rays
EAS properties can be used to estimate the mass
energy of the incident particle using MC
James Pinfold Prague June 2004

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EAS -- the Atmosphere as a Calorimeter
Transverse profile
Longitudinal profile

• Fluorescence Detectors
• Atmosphere is sensing calorimeter
• Measure the longitudinal distribution
• Ground Arrays
• Technique developed in the
  50s
• Measure the lateral distribution at ground

Auger - measuring transverse Longtudinal
shower profiles
James Pinfold Prague June 2004

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Measuring EASs

• EAS measurement is an indirect method to
  determine
• mass A of primary CR
• energy E of primary CR.
• These quantities are inferred from

James Pinfold Prague June 2004

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Cosmic Rays Experiments Worldwide
Expts in space
Atmospheric flour. 2 site 14 km apart
100 detector surface array
EUSO or OWL
Artists impression
Cerenekov telecopes
Ice cerenkov

• water det.
• 4 atm. fluor. det.

James Pinfold Prague June 2004

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Sensitivity of Future Detectors
James Pinfold Prague June 2004

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Tantalizing Hints of Non-random Cosmic Ray
Phenomena

• The Japanese LAAS array(2000), 8 stations sep. by
  50 km.
• Anisotropy of successive air showers within a
  Dt of 20 minutes, a concentration of directions
  in the galactic plane is evident the chance
  probability is 0.077.
• The Swiss array (1988-89) 4 detectors enclosing
  5K km2.
• An excess of events in which each detector was
  hit within 0.62 ms was observed with a
  significance of 4.8s (prob 10-4).
• The Irish (U.C. Dublin/Cork) Array (1975) 2
  stations each with 4 scintillators, separated by
  250 km.
• Fegan et al reported an unusual simultaneous
  increase in the cosmic-ray shower rate at the two
  recording stations, the event lasted 20s
  statistical probability 3 x 10-5.
• The Manitoba Air Shower Array (1980) consists
  of three 1m2 plastic scintillators enclosing an
  area 60 m2.
• A burst of 32 EASs was observed within a 5-min
  period. This observation was the only one of its
  kind in an 18 month period in which 150K of such
  showers were recorded. Stat. prob. 10-35 !!

James Pinfold Prague June 2004

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Sparse Very Large EAS Array Networks

• Experimental purpose of such array networks is to
  look for a possible no-random component in cosmic
  rays
• Look for coincident events in small windows
  around arrival time and direction at separated
  sites (DX from 1?500 kms) using GPS timing
• One can detect and point very high energy,
  multiple primary, phenomena this way
• When detectors are close enough (not more than a
  few kms) one can count and point UHECR

Dt
James Pinfold Prague June 2004

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Experimental Concept

• Small air showers arrays operated independently
  at each site Typically a few to several small
  detectors at each site separated by 10m.
• Local pointing with accuracies as good as 2o
• GPS now provides the common clock with
  accuracies 20 ?50 ns over areas as large as
  North America.
• Local coincidence data readout to a central site
  where an offline trigger involving direction,
  time and pulse height can be applied.
• Standard data format and accessibility via the
  internet

James Pinfold Prague June 2004

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The Mystery of Very Large Area Cosmic Ray
Phenomena

• Correlated phenomena, Possibilities
• Photo-disintegration of UHE nuclei in the
  photosphere of the Sun
• VHE Gamma Rays from GRBs
• Relativistic dust grains
• Neutrino bursts
• Primordial black holes
• Cosmic strings
• Ultra high energy (UHE) horizontal air showers
  (giving a coincidence between separated detectors
  thus faking a correlated event)

James Pinfold Prague June 2004

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The LAAS Array
(First results 1999)
Okiyama University
Typically very small air showers arrays (10x10
m2) with about 8 detectors (0.25 m2) at each
site.
James Pinfold Prague June 2004

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Sparse Very Large Area Networks of Educational
EAS Arrays.

• Physics aims of these experiments are those of
  sparse very large area air shower arrays.
• In this case the detectors are housed in
  high-schools and colleges and involve
  high-schools students and teachers
• These arrays thus have BOTH an educational
  component as well as a research component
• The ALTA project in Alberta was the first in
  North America ( the world?) to actively pursue
  an array that would satisfy equally these two
  aims.
• The ALTA experience has been taken up across
  North America and in Europe.
• ALTA now leads (along with CROP) a consortium of
  similar projects called NALTA (North American
  ALTA)

James Pinfold Prague June 2004

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North American Large Area Time Coincidence Arrays
(NALTA)

• ALTA U. of Alberta, Athabasca U, (Northeastern
  U, Boston)
• BC-ALTA U. of BC
• CANLACT U of Alberta, U. of Athabasca, UBC,
  Carleton U., U of Manitoba, U of Regina, U of
  Victoria
• CosRayHC U. of Pittsburgh, Southern U. of
  Illinois at Edwardsville, Jackson State U.,
  Florida State U.
• CROP U. of Nebraska
• CHICOS Caltech, California State U at
  Northridge, U. of California at Irvine
• SALTA SNOWMASS-2001, Colorado
• SCROD Northeastern University
• TECOSE University of Texas
• WALTA University of Washington
• MEXICO Groups around Mexico city

100 detector systems Across North America
James Pinfold Prague June 2004

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ALTA The 1st Example of a Sparse Large Area
Educational ArrayNetwork

• 20 Schools Involved
• 13 detectors systems deployed in Alberta
• 2 more being equipped
• 2 more for next spring
• 20 detector systems in place by the end of 2004
  
• All timed together using the GPS system

James Pinfold Prague June 2004

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The ALTA Detector Systems
GPS
The electronics readout
0.5 m2 Scint.
James Pinfold Prague June 2004

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The System Cost

• Detector cost 1,900 EUR
• Readout electronics calibration
  system 5400 EUR
• HV power supplies 600 EUR
• Temp. mon. control 380 EUR
• GPS Satellite receiver 630 EUR
• DAQ Computer 950 EUR
• Sundries 250 EUR
• TOTAL 10,000 EUR

3 x
1 x
1 x
1 x
Data acquistion computer
Readout Electronics
GPS Receiver electronics
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Properties of the Detector

• LOCAL COINCIDENCE obtained using local system and
  hardwired electronics. Allows pointing of shower
  direction to ? 2-gt3 degrees.
• GPS TIME STAMP is obtained when a local
  coincidence occurs. Timing is good to 15 ns over
  Alberta (NIM paper on this has been accepted).
• MIP SENSITIVITY. Each detector should respond to
  a single MIP.
• ENERGY THRESHOLD for the local detector with a
  10m triangle is 1014 eV (from Corsika)
• OFFLINE TRIGGER timed stamped local
  coincidences, or events, are stored centrally for
  various offline studies.

Average size Of a 1014 ev shower
10m
James Pinfold Prague June 2004

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First Data is Being Analyzed
Local coincidence rate

• No physics results are ready as yet
• However, we do have a nice result relating to the
  correlation between trigger rate and atmospheric
  pressure
• It provides a nice way to check that detectors
  are working over a large area

Atmospheric pressure
(
James Pinfold Prague June 2004

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North American Large Area Time Coincidence Arrays
(NALTA)
CANALTA
CANALTA
CANALTA
ALTA
BC-ALTA
CANALTA
CANALTA
CROP
SCROD
WALTA
CosRayHS
CosRayHS
SALTA
CosRayHS
CHICOS
TECOSE
CosRayHS
Detectors in place
Mexico City, etc.)
In preparation
In planning
James Pinfold Prague June 2004

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An Example of a Proposed Array in Italy EEE
(Extreme Energy Event network))

• Possibility of 4 sites in Italy.
• Project run under the auspices of the Enrico
  Fermi Institute in Rome
• Contact people Prof. A Zichichi Dr Rinaldo
  Baldini.
• As part of this project Prof Zichichi has
  proposed a search for cosmic ray coincidences
  with ultra long baselines (between ALTA EEE)

James Pinfold Prague June 2004

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Lets Network the Cosmic Rays Experiments
Worldwide
Internet based ALTA arrays in schools could be
networked with the Worlds largest Cosmic Ray
detector system
ALTA
CANALTA

• ALTA type
• projects in
• 1) Czeck Republic (planning)
• 2) Germany,
• 3) Italy (planning)
• 4) Denmark

NALTA
James Pinfold Prague June 2004

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We Could Include Gravitational Wave Detectors in
the World Wide Network
James Pinfold Prague June 2004

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ALTA Hand on Workshop Nov. 2001

• Workshop held as introduction to the physics as
  well as hands on training with detectors.

The crowded workshop area
At the U of Alberta
Alberta high-school
James Pinfold Prague June 2004

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The CROP Project (U. of Nebraska)

• Major funding received from NSF (1.34M over 5
  years)
• 11 high-schools involved in project so far (more
  to follow)
• Basic detector setup has four plastic
  scintillators with separation 10m.
• Enough PMTs scintillators, HV retrieved from
  Dugway to supply 300 schools.

CROP Workshop Participants July 2000
James Pinfold Prague June 2004

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The CROP Project July Workshop
The Zoo School (Lincoln) team wrapping a CASA
scintillator 25 July 2000
James Pinfold Prague June 2004

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The CHICOS Project (U. of California)

• Proposing to involve 14 high-schools in the array
  in the Los Angeles area
• Plan is to field detectors in schools in the San
  Gabriel valley in 2001
• Prototype detectors stations are working
  (refurbished CYGNUS detectors)
• 200 detectors and PMTS in hand from LANL.

James Pinfold Prague June 2004

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Summary Conclusions

• Around 15 universities 80 high-schools
  involved so far
• 42 detector systems have been deployed (ALTA has
  9, CHICOS 18, CROP 11, WALTA 4) -- we expect to
  deploy 100 in a few years.
• NALTA like efforts are now international with
  projects in Canada, China, Belgium, Czech
  Republic (?), Germany, Italy(?), UK and the USA
• We will be working on making the NALTA network
  function as a unified system so that data can be
  shared and common standards set. Essentially
  NALTA could become a hyper-large area sparse
  array capable of looking at very large area
  and/or new cosmic ray phenomena.
• We expect NALTA to excite and interest new
  generations of physicists with an educational
  paradigm utilizing distributed interactive
  learning/research systems that can be adapted to
  many areas the environment (air pollution
  measurements), geophysics (simple seismometers),
  meteorology (weather stations), etc.

James Pinfold Prague June 2004