extreme energy events (eee)

EXTREME ENERGY EVENTS (EEE) –
THE SCIENCE IN THE SCHOOLS
________________________________________________
Project leader: Prof. Antonino Zichichi
General Background
The Centro Fermi has established an effective contact with the world of schools, opening a
debate on the teaching of physics in secondary school, to create physics laboratories for advanced
teaching, where teachers and students are protagonists.
To do this, in the last three years the Extreme Energy Events (EEE) Project, of which Centro
Fermi and in particular its first President, A. Zichichi, are initiators and propagators, has been
definitively established.
For its implementation and funding, agreements have been signed or are being signed with:
- the Ministry of Education, University and Research (MIUR),
- the Istituto Nazionale di Fisica Nucleare (INFN),
- the European Organization for Nuclear Research (CERN),
- the Foundation-"Ettore Majorana" Centre for Scientific Culture (FEMCCS),
- various high schools and technical institutes, involved in the Project.
The Project stems from the following considerations. On the Earth we live immersed in a flow
of "rays", called cosmic because they come from the farthest reaches of outer space, far beyond the
Moon, the Sun and the same stars visible to the naked eye. These rays, which travel for millions and
millions of years, are essentially made of protons and constitute the "ash" of the Big Bang. Arriving
near our planet, cosmic protons meet the highest layers of our atmosphere. When a proton
encounters a layer of matter, it interacts with the nuclei of which matter itself is made. In the
interaction, other subnuclear particles are produced but they live very shortly (billionths of a
second). In their short life they are transformed into other particles whose last stage are muons. At
sea level the bulk of cosmic rays is made of muons.
Muons are particles identical to electrons that are part of atoms and molecules familiar to us.
The unique diversity of muons is to be 200 times heavier than electrons. The reason for this
difference is still one of the unsolved problems in physics today. Another open question is about the
origins: where, when and how the cosmic protons originate. Here, then, the interest in studying high
energy cosmic events: Extreme Energy Events (EEE).
In each school of the Project, a "telescope" is constructed, made with the most modern and
advanced particle detectors, to be in coincidence with the telescopes of other schools in order to
reveal the cosmic muons and extensive air showers (also wide as entire towns) produced by cosmic
rays of the highest energy. The students have the important task of the construction of the detectors,
starting from poor material and realizing high-precision instruments.
Cosmic rays may have significant implications in our lives, with effects ranging from climate
change to genetic mutations, to mention only a few examples of the problems related to their study.
The data that are collected in each school are an original contribution to the study of cosmic rays
belonging to the EEE class. Having to do with cosmic rays, in the students and their teachers a
direct interest arises in the new problems related to particle physics and high technology.
The Project is structured on a modular basis, because in each participating school a telescope is
built and then managed, but at the same time a national network is set-up, connecting all the schools.
The goal of EEE Project is therefore to bring science into the heart of young people, even the
very young, through a direct action that begins when students feel they have become protagonists in
the construction of an instrument, and continues with the elaboration of data that are at the frontiers
of scientific thought.
The realization of a network, which in general permits the exchange of scientific information at
this level, is in itself a goal of great importance that can be exploited for additional applications
(seismography, environmental pollution control, etc..), always related to the diffusion of scientific
culture. In this perspective, the Project for the construction of a network able to detect cosmic
particles should be considered as a first step.
Figure 1. Scheme of the detectors – electronics- data acquisition and distribution system.
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Since 2006, the Centro Fermi has actively worked to develop the project, first proposed in 2004:
the type of detector was chosen: Multigap Resistive Plate Chamber (MRPC), also adopted in
ALICE experiment at the Large Hadron Collider (LHC) at CERN, in a suitably simplified
version. Three detectors for each telescope are used in the schools, in order to accurately
measure the direction of origin of muons and their time of arrival. The scheme of the system
"telescope" is shown in Figure 1.
At the beginning, a pilot group of schools, 20 institutes grouped in different cities spread across
the country, was involved.
Every year new schools have been added, and their number in 2012 has grown up to 36 (see
Table 1).
The construction of the MRPC detectors is carried out by the students and teachers involved in
the Project, assisted by staff of the Centro Fermi and INFN, at the CERN laboratories in
Geneva.
The necessary equipment, namely the mechanical structure, PC, oscilloscope, GPS system and
readout electronics of the signals, is usually bought by Centro Fermi, but often the school
contributes to the purchase of a part of it.
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The detectors built at CERN are then transported to the school.
The detectors’ performances are tested on site at the telescope, measuring space and time
resolution.
A successful process of collecting data for the study of cosmic rays and the search for
similarities between the telescopes in different schools is running continuously.
Main results
At present all the built stations are fully operational and continuously in data taking, in order to
look for coincident events among close and distant stations.
Table 1 lists the high schools involved in the Project, including those where the telescopes are
already operational and those where the installation of the telescopes is in progress. Additional
telescopes not mentioned in this list are installed in research laboratories at CERN and at INFN
Bologna Section.
In 2012 three groups of students and teachers, from Liceo Scientifico Scorza (Cosenza), Liceo
Scientifico Gandini (Lodi), and Liceo Scientifico Fardella (Trapani), respectively, have attended the
stage at CERN to take part in the construction of the MRPC chambers.
The EEE Project activity resulted in publications, talks at international congresses and degree
theses. The publications and additional material, multimedia as well, are available on the EEE
Project web page: http://www.centrofermi.it/eee.
As an example, we mention three publications of particular importance:
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“First detection of extensive air showers with the EEE experiment”
EEE Collaboration (M.Abbrescia et al.)
Il Nuovo Cimento B 125 (2010) 243.
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“Observation of the February 2011 Forbush decrease by the EEE telescopes”
EEE Collaboration (M. Abbrescia et al.)
The European Physical Journal EPJ Plus 126 (2011) 61.
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“The EEE Project: cosmic rays, multigap resistive plate chambers and high school students”
EEE Collaboration (M. Abbrescia et al.)
JINST (accepted for publication – 2012 October).
Other two manuscripts are under preparation in order to be submitted to The European Physical
Journal EPJ Plus; they are:
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“The EEE experiment: status and first physics results”.
“Cosmic rays Monte Carlo simulations for the EEE (Extreme Energy Events) project”.
The 2nd Conference of the Centro Fermi Projects was held at the Viminale Conference Room on
April 19 and 20, 2012; during the second day, the afternoon session was devoted to the EEE Project
and to the presentation of the activities done in several high schools, with the participation of many
students and teachers belonging to schools involved in the Project.
Table 1: High Schools involved in the EEE Project
with operational (or working soon) telescopes.
Istituto Scolastico
1. Liceo Cagnazzi
2. Liceo Scacchi
3. Liceo Sabin
Città
Altamura (BA)
Bari
Bologna
4. Liceo Fermi
5. Liceo Galvani
6. Liceo Pacinotti
7. Liceo Alberti
8. Liceo Michelangelo
9. ITIS Cannizzaro
10. Liceo Fermi
11. Liceo Scientifico Scorza
12. Istituto Villa Sora
13. ITIS Fermi
14. Rete Scuole della Cittadella dello Studente
15. Liceo Touschek
16. ITIS Amedeo d’Aosta
17. Liceo Bafile
18. Liceo Palmieri
19. Liceo Banzi Bazoli
20. ITIS Fermi
21. Liceo Scientifico Gandini
22. Liceo Marconi
23. ITIS Nobili
24. Liceo Da Procida
25. Liceo Chiabrera
26. Liceo Grassi
27. ITIS Ferraris
28. ITIS Alessandrini
29. Liceo Galileo Ferraris
30. Liceo Giordano Bruno
31. Liceo Volta
32. Liceo D’Azeglio
33. Liceo Fardella
34. Liceo Staffa
35. Liceo Barsanti
36. Istituto Nautico Artiglio
Bologna
Bologna
Cagliari
Cagliari
Cagliari
Catania
Catanzaro
Cosenza
Frascati (RM)
Frascati (RM)
Grosseto
Grottaferrata (RM)
L’Aquila
L’Aquila
Lecce
Lecce
Lecce
Lodi
Parma
Reggio Emilia
Salerno
Savona
Savona
Savona
Teramo
Torino
Torino
Torino
Torino
Trapani
Trinitapoli (BT)
Viareggio
Viareggio
The analysis of time correlations for the detection of muons belonging to extensive air showers
was successfully performed on data acquired with telescope clusters installed in Bologna, Cagliari,
L’Aquila, Frascati (Roma).
Figure 2 illustrates the first results of the time coincidence analysis performed on data acquired
with two EEE telescopes in L’Aquila, installed at the ITIS "Amedeo di Savoia" and Liceo
Scientifico "Andrea Bafile", respectively. It is the first detection of extensive air showers ever done
with MRPC detectors installed at schools, outside research laboratories.
Distribution of the arrival time difference
of cosmic muons detected in two different
telescopes. The peak of the coincidence
events due to muons belonging to the same
shower clearly stands out against the flat
background.
Difference of muons arrival time as a
function of the incident direction of the
shower.
Distribution of the arrival time difference
of cosmic muons, once corrected for the
spreading effect due to the shower
inclination angle.
The data indicate a coincidence rate of 7.6
events/hour, for telescopes placed 180
meters apart.
Figure 2: First coincidences observed by two EEE telescopes.
On February 2011, an important effect connected to the solar activity was observed with the
EEE telescopes. For the first time a sudden decrease of the cosmic ray flux, known as Forbush
decrease, was observed for the muon component by the EEE telescopes and this variation was
compared with what measured by the Oulu Cosmic Ray Station in Finland, which is devoted to the
measurement of the neutron component of the comic ray flux: the phenomenon was observed by
two different EEE telescopes, one installed in Catania and the other in Altamura (Figure 3). This is
another result absolutely original in terms of detection setup.
ge 6 of 7
The European Physical Journal Plus
g. 4. Time variation
of thevariation
measured
cosmic-ray
flux in the
two
telescopes,
foratmospheric
atmospheric
pressure variati
Figure 3: Time
of the
measured cosmic-ray
flux
in EEE
two EEE
telescopes,corrected
corrected for
pressure
variation.
In the same plot the
corresponding
neutron
flux, as by
measured
by theneutron
Oulu neutron
station
is also
the same plot
the corresponding
neutron
flux, as
measured
the Oulu
station
[14]
is shown.
also shown.
Figure 4 shows another result of the time correlation analysis, which was performed on data
acquired by two telescopes placed 520 m apart, installed in Cagliari, respectively at the Liceo
"Michelangelo" and Liceo "Pacinotti". The coincidence peak is clearly visible. The analysis was
done implementing a software code to correlate muon events within a delay time window of 10 µs,
over a period of 10 days of data taking.
g. 5. Correlation plot between the counting rate measured by the Oulu neutron monitor and the EEE telescopes, during t
riod spanning the Forbush decrease following the mid-February solar flare.
fferent muon energy thresholds for the two detectors, the threshold for the Catania telescope being larger than
e Altamura telescope.
3 Angular dependence of the amplitude variation
he possibility to measure, event by event, the orientation of each incoming muon, allows to investigate in princip
e dependence of the Forbush effect upon the zenithal angle of the muons. In the case of very intense solar flares it w
scussed [4] that a reduction of the Forbush amplitude could be evidenced for muons arriving with a larger zenith
gle, since they
are supposed to be associated to higher-energy primaries, due to the atmospheric thickness th
Figure 4. Preliminary analysis of time correlation between muons detected by two EEE telescopes in Cagliari. The time
averse, whiledifference
the amplitude
of abscissa
the Forbush
decrease
should
be larger
verticalof muons.
However, the da
reported on the
axis is measured
with the
GPS units,
which arefor
partnearly
of the electronics
the telescopes.
ncerning these findings are very sparse, since the statistics usually required to evidence such effect is very large. In
ries of Forbush decreases following solar flares of various intensities [4] only in a few cases was this trend observed.
vestigate this aspect, we also extracted the muon counting rate variation during the Forbush decrease for differe
ervals of the muon zenithal angle. Data were classified into four classes, according to the value of the zenithal an
–10◦ , 10◦ –16◦ , 16◦ –22◦ and larger than 22◦ ). The intervals were chosen so as to have nearly the same number
ents in each class. The time dependence of the counting rate was then extracted for each class, after correcting t
ta for pressure variations. The results are presented in fig. 6, which shows how the effect is clearly visible at
gles, almost with comparable intensity, which does not allow at the moment to extract a reliable dependence of t
rbush amplitude as a function of the zenithal angle, due to large fluctuations and systematic uncertainties given