CRESCERE

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CRESCERE
COSMIC RAYS IN A EUROPEAN SCHOOL ENVIRONMENT A
REMOTE EXPERIMENT
COLEGIUL NATIONAL Mihai Viteazul, Sf.
Gheorghe, ROMANIA
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THAT REACHED VARIOUS CORNERS OF THE CONTINENT
PORTUGAL, ITALY AND
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ROMANIA
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In the following, we will show you some pictures
from our country
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MEASUREMENT OF COSMIC RAYS FLOW
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The team Aralda Chirita Anda Panaitiu Adriana
Oltean Alin Iordache Adriana Nichitoiu Oana
Muntean Laurentiu Gavrila Bogdan Ciambur Anca
Lacatusu Bogdan Stînga Stefan Gradinar Cristian
Buceceanu coordinated by prof. Luminita
Curceanu
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AND THE TEAMS HEADQUARTERS
COLEGIUL NATIONAL
MIHAI VITEAZUL
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The cosmic rays are particles coming from every
corner of the Universe, generating a shower of
many other particles that eventually reach the
Earths surface. The most numerous of the latter
are called muons which have the same electric
charge as the electron but are 210 times heavier.
The so-called shower forms due to the very high
energy of the initial particle.
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• The aim of the experiment from LIP is the
  measurement of the flow of cosmic rays at the
  earths surface. This is done with the help of
  the Cosmic Rays Telescope (CRT), by using the
  detectors it is composed of, which have the
  following components
• two detection modules, made of
• - a plastic scintillator block
  of the following dimensions 1 x 0,5 x 0,01
• - a light guide
• - a photomultiplier
• a data acquisition board installed into a PC

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The cosmic rays flow is defined as expressed in
the formula
Dtf dead time fraction Eff efficiency S
scintillator surface t time
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• Dtf represents the time fraction in which the
  equipment does not acquire data due to the fact
  that it is processing the data provided by the
  last particle that hit the scintillator, Eff
  represents the efficiency for the selected
  threshold and high voltage, and the surface ( of
  the scintillator) is equal to 0.5 m2.
• The equipment is handled through a LabView
  interface, via web.
• At the beginning of the data acquisition, the
  school in possession of the red code needs to
  select values for the number of events that will
  be acquired, the threshold, the high voltage and
  the Trigger Type button must be set to Muon.
• Based on the acquired data and on the
  acquisition conditions, the following must be
  performed
• the measurement of the cosmic rays flow
• the measurement of the energy deposited in the
  scintillator
• the study of the flow-threshold dependence
• the study of the signal amplitude - high voltage
  dependence.

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• The measurement of the cosmic rays flow

The error of the flow is expressed by the formula
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• Between 105447 - 110610, with a total number
  of 500 events throughout a time period of 683s,
  for the selected threshold of 80mV and a high
  voltage of 1441 V, with dtf 0.04 and Eff 0.01
• Between 112111 - 115359, with a total number
  of 1500 events throughout a time period of
  1968s, for a selected threshold of 80mV and a
  high voltage of 1441 V, with dtf 0.07 and Eff
  0.01
• 3. Between 115726 - 122018, with a total
  number of 1000 events throughout a time period of
  1372s, for a selected threshold of 60mV and a
  high voltage of 1441 V, with dtf 0.06 and Eff
  0.01

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The value of the flow obtained from the data in
the first flow is F1 152.51342
6.820607 ev./(sm2) The value of the flow
obtained from the data in the second file is
F2 163.91293 4.232213 ev./(sm2) The value
of the flow obtained from the data in the third
file is F3 155.07723 4.903972 ev./(sm2)
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The average value of the flow can be determined
according to the formula
The error for the average flow can be determined
according to the formula

• The average value of the flow is
• lt F gt 158.681195 2.899984 ev./sm2

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(2) The measurement of the energy deposited in
the scintillator The energy of a particle,
corresponding to one event, is determined by
using the formula
The average value of the energies corresponding
to the events found in one set of data is
determined according to the formula
The average value of the energy deposited in the
first scintillator can be determined by using the
formula
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• For the first file, the average value of the
  energy deposited in the first scintillator is
• ltEgt1 2,645838 MeV 4,2333 10-13 J

• For the second file, the average value of the
  energy deposited in the first scintillator is
• ltEgt1 3,020358 MeV 4,8325 10-13 J
• For the third file, the average value of the
  energy deposited in the first scintillator is
• ltEgt1 2,8495571 MeV 4,5592 10-13 J

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We can also introduce the variation of the energy
Thus, the error of the average value of the
energy can be determined as follows
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The variation of the energy deposited in the
first scintillator can be written as follows

• For the first file, the variation of the energy
  is
• V(E) 52.6303 MeV2
  134.7335 10-26 J2
• For the second file, the variation of the energy
  is
• V(E) 55.6536 MeV2
  142.4732 10-26 J2
• For the third file, the variation of the energy
  is
• V(E) 55.0641 MeV2
  140.964 10-26 J2

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For the first file, the error of the average
energy deposited in the first scintillator is
DltEgt 0.3244 MeV 0.519
10-13 J
For the second file, the error of the average
energy deposited in the first scintillator is
DltEgt 0.1926 MeV 0.3081 10-13 J
For the third file, the error of the average
energy deposited in the first scintillator is
DltEgt 0.2346 MeV 0.3753 10-13 J
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(3) The study of the flow-threshold dependence
In order to perform this experiment, different
values of threshold (between 30mV and 80mV) need
to be selected.
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( 4 ) The study of the amplitude of the
signals-high voltage dependence In order to
realize this study, different high voltage values
need to be selected, by varying by 50 V, so that
the values are no higher than 1500 V and no lower
than 1200 V. Also, in order to accomplish this,
the threshold value needs to be maintained the
same.
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When we deal with two sets of data that have
identical acquisition conditions threshold and
high voltage the compatibility can be
determined. The latter is defined by the
following formula
where F1 and F2 represent the flows determined
based on the two data sets, and DF1 and DF2 are
the corresponding errors.
If the determined value is between 1 and 3, the
two data sets are compatible.
The value obtained is 1.42015
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Before concluding, we wish to express a few of
our thoughts and feelings in that which concerns
the CRESCERE project, in general, and this
experiment in particular. Thus, before anything
else, we would like to mention that we are
thankful for having been part of this project and
for having had the chance of getting a closer
view on the world of research. We are very
grateful for the opportunity we have been given.
This project has meant a lot to us because we
found out what research in physics and in general
means and what it implies. We have worked in
teams and learned how to complete, to understand
and help each other, it has made us bond and
understand what team work is really all about.
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Because this project has been a gateway to the
world, we also communicated with most of the high
schools in Romania and kept in touch. Nothing
would have been possible if the initiators of the
CRESCERE project wouldnt have thought that if
young students are not implied in research in
physics during their studies in high school, they
cannot chose to study and involve themselves
later in this extremely interesting scientific
area. This is why we have to thank PEDRO ABREU,
our online teacher, who guided us throughout this
project and the entire team from Portugal. We are
thankful, and hope that this initiative will
continue and that its results will be noticed,
even later on, when the next generations of
physicists, who took part to these ambitious
project, will continue to discover what is still
unknown our days.