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

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

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

The Energy Range High energy cosmic rays consist of protons, nuclei, gammas,… Measured flux extends to s 1/2 ~ 400 TeV Highest energy particles are extremely rare Supernova shock fronts can accelerate particles upto eV Above ~10 15 eV, presumably acceleration is in AGNs (?) How do UHECR protons evade the GZK cut-off at ~7 x eV (if source is >100Mps away)? GZK Cut-off “Knee” “Ankle” 1/m 2 /s 1/km 2 /year 1/m 2 /year James Pinfold Prague June 2004

Mysteries of the Spectrum Protons are trapped in our Galaxy (  G B-fields) up to ~ eV Protons can travel straight above ~10 20 eV Supernova shockwave acceleration up to ~10 15 eV Above the knee the acceleration mechanism is essentially unknown: AGNs, massive black holes systems, gamma ray bursts ? eV eV GZK land James Pinfold Prague June 2004

Acceleration of CRs above the Knee Up to the knee Fermi acceleration (FA) in supernova shock fronts can “explain” the spectrum: E max ~R SNR x Z x B x  sh This can be used to constrain the size and magnetic field requirement if acceleration mechanism is 1 st 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 eV. The HILLAS Plot James Pinfold Prague June 2004

The Mysteries of an Opaque Universe The universe is opaque to UHECR In the case of the GZK cut-off a 5x10 19 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 > E GZK getting to us? There are two scenarios: BOTTOM UP: acceleration in AGNs, gamma rays bursters, etc. then production of a neutral (, s o,..?). 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. 10,000Mpc Size of observable universe Region restricted by GZK cut-off ~100 Mpc James Pinfold Prague June 2004

Life Above the GZK Cut-off ? ? GZK HiRes vs. AGASA UHECRs as of billion particles Fly’s Eye Big event 3 x eV (50J!) (4  10)x10 19 eV > eV 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 > eV Some debate as to possible sources… Some 6 doublets and 1 triplet of events have been seen within 2 o cones HI-Res. + AGASA James Pinfold Prague June 2004

Extended Air Showers There are many ways of detecting cosmic rays EAS properties can be used to estimate the mass & energy of the incident particle using MC eV 15 km 100m N e & N  correlation Particle density at ground level Particles/m 2 James Pinfold Prague June 2004

EAS -- the Atmosphere as a Calorimeter Fluorescence Detectors –Atmosphere is sensing calorimeter – Measure the longitudinal distribution Ground Arrays –Technique developed in the 50’s –Measure the lateral distribution at ground Transverse profile Longitudinal profile Auger - measuring transverse & Longtudinal shower profiles James Pinfold Prague June 2004

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

Cosmic Rays Experiments Worldwide 100 detector surface array Artists impression Atmospheric flour. 2 site 14 km apart 1600 water det. 4 atm. fluor. det. Expts in space Cerenekov telecopes EUSO or OWL Ice cerenkov James Pinfold Prague June 2004

Sensitivity of Future Detectors James Pinfold Prague June 2004

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  t of 20 minutes, a concentration of directions in the galactic plane is evident – the chance probability is The Swiss array ( ) – 4 detectors enclosing 5K km 2. –An excess of events in which each detector was hit within 0.62 ms was observed with a significance of 4.8  (prob ). 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 The Manitoba Air Shower Array (1980) – consists of three 1m 2 plastic scintillators enclosing an area ~60 m 2. –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. ~ !! James Pinfold Prague June 2004

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 (  X 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 tt James Pinfold Prague June 2004

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 ±2 o 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

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

The LAAS Array Typically very small air showers arrays (10x10 m 2 ) with about 8 detectors (0.25 m 2 ) at each site. Typically very small air showers arrays (10x10 m 2 ) with about 8 detectors (0.25 m 2 ) at each site. Okiyama University (First results 1999) James Pinfold Prague June 2004

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

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

~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 ALTA The 1 st Example of a Sparse Large Area “Educational” Array Network James Pinfold Prague June 2004

0.5 m 2 Scint. The ALTA Detector Systems GPS The electronics readout James Pinfold Prague June 2004

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 GPS Receiver & electronics 1 x Readout Electronics Data acquistion computer 1 x

Properties of the Detector LOCAL COINCIDENCE obtained using local system and hardwired electronics. Allows pointing of shower direction to  2- >3 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 eV (from Corsika) OFFLINE “TRIGGER” timed stamped local coincidences, or events, are stored centrally for various offline studies. 10m Average size Of a ev shower James Pinfold Prague June 2004

First Data is Being Analyzed 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 Local coincidence rate ( James Pinfold Prague June 2004

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

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

Let’s Network the Cosmic Rays Experiments Worldwide “ALTA” type projects in; 1) Czeck Republic (planning) 2) Germany, 3) Italy (planning) 4) Denmark NALTA ALTA Internet based “ALTA” arrays in schools could be networked with the World’s largest Cosmic Ray detector system CANALTA James Pinfold Prague June 2004

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

ALTA “Hand on” Workshop Nov 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

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

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

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

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