On PRISMA project (proposal)

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On PRISMA project (proposal)

• Yuri V. Stenkin
• INR RAS

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The Project aims

• Why PRISMA?
• PRImary Spectrum Measurement Array
• The main aim is TO SOLVE THE KNEE PROBLEM
• Other aims
• cosmic rays spectra and mass composition
• cosmic ray sources
• applied Geophysical measurements

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History Motivation
Why we need a new project? 1. The knee problem
is a milestone of cosmic ray physics. 2. Very
few experiments have been designed specially for
that and KASCADE (KArlsruhe Shower Core and Array
DEtector) is the best one. 3. The problem still
exists.
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EAS method
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1. The knee problem
The problem is exactly 50-years old! In 1958
there was published a paper (G.V. Kulikov G.B.
Khristiansen) claiming the knee existence in
cosmic ray energy spectrum. They observed a
sharp change of slope in EAS size spectrum and
proposed a model describing this effect as an
evidence of existence of 2 sources of c. r.
Galactic and Metagalactic ones.
But, from the beginning and up to now there exist
alternative explanations of this effect
(S.I.Nikolsky, Kazanas Nikolaidis,
A.A.Petrukhin, Yu.V. Stenkin).
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Examples of alternative explanations
Petrukhin
Stenkin
New processes
EAS method systematic
knee
knee
Primary energy
EAS energy
Primary energy
E
Primary energy
Missing energy
Missing energy
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EAS components equilibrium
No of particles
Break of equilibrium
Break in attenuation
knee in Ne spectrum
Depth in atmosphere
From Hayakawa manual on cosmic ray physics
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When the break occurs?

• At E100 TeV / nucleon
• For p 100 TeV
• For Fe 5 PeV (just the knee region)

This figures are sequences of Lint 90 g/cm2 in
air the Earths atmosphere thickness 1030 g/ cm2
(depending on altitude)
For details see Yu.Stenkin, Yadernaya Phys., 71
(2008), 99
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2. Existing experiments

• KASCADE
• It gave many interesting results.
• BUT, it did not answer the question on the knee
  origin and thus,
• It has not solved the knee problem!
• Moreover, the problem became even less
  clear.(see G. Schatz. Proc. 28th ICRC, Tsukuba,
  (2003), 97
• or Yu. Stenkin. Proc. 29th ICRC, Pune (2005),
  v.6, 621)

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KASCADE -gt KASCADE-Grande
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KASCADE hadronic calorimeter
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KASCADE group connected visible knee in PeV
region with c. r. protons.
Tibet AS experiment results contradict this
hypothesis they connect the knee with iron
primary.
In this case there should be the iron knee at
E1017 eV.
- Nobody saw this.
C. R. should consist only of heavy nuclei at
Egt1017 eV or one has to adjust many parameters to
make full compensation.
- Nobody saw this. It contradicts emulsion
chamber experiments (Pamir) and air luminescence
data (Hi Res).
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Compilation of experimental data
(astro-ph/0507018)
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KASCADE EAS h-size spectra
knee???
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A. Haungs, J. Kempa et al. (KASCADE) Report
FZKA6105 (1998) Nucl. Phys. B (Proc. Suppl.)
75A (1999), 248
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to make a device based on new principles
(asymmetrical answer)
KASCADE is very precise classical instrument for
EAS study. It would be difficult and useless to
try to make better array.
On my opinion the only way is
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PRISMA would be the answer.
PRISMA
Prism
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New principles
The main EAS component is hadrons
Therefore, let us concentrate mostly on the
hadronic component
Bun, instead of huge and expensive hadron
calorimeter of fixed area, let us make simple,
inexpensive and of unlimited area detector.
How this could be done?
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New Methods
2 new methods have been developed in our
Lab. 1st method is based on thermal neutrons
vapour accompanying EAS
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(No Transcript)
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en-detector design
PMT
plastic
housing
ZnS(Ag) is a unique scin- tillator for heavy
particles detection
6Li(n,a)3H4.8 MeV
Scintillator ZnS(Ag)6LiF
Similar to that using in neutron imaging technique
160,000 photons per capture
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The detector is almost insensitive to single
charged particles. But, it can measure the number
N of charged particles if Ngt5.
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Thermal neutron time distributions
Multicom Prototype, Baksan
Prisma prototype, Moscow
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Another advantage of this detector is a
possibility to measure thermal neutron flux of
low intensity and its variations
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2d new method
The Muon Detector as a 1-layer hadronic
calorimeter
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This picture represents a density map as measured
by Carpet (left, shown in LOG scale) and by MD
(right, linear scale in relativistic particles).
(Detector in the center show a particle density
of ?c81.1252/0.55800 m-2. jet of
(2617)/221.5 particles per m2 in MD. Jet size
is very narrow (1 m) with normal rather low
density around it and second the distance from
the EAS core is large enough and equal to 48 m.
r jet 21.5 /m2
r core 5800 /
m2
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Preliminary Baksan data hadrons at R47m
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Muon/hadron ratio distribution
Preliminary data
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Carpet 4001m2 en-detectors grid with spacing of
5 m Central muon detector 4001m2 plastic
scinillators Muon detector tunnels 12001m2
plastic scintillators Outer trigger
detectors 4251m2 plastic scintillators
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M-C simulations. CORSIKA 6.501 (HDPM, Gheisha6)
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M-C simulations. CORSIKA 6.501 (HDPM,
Gheisha6)array
A map of an event in neutrons
Ne 407158 Nmu 794 E0/1TeV
355.0245 x0 -4.448307 y0 -27.31079 TETA
13.80 FI 161.49 Z 3094504.
Part_type 5626
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M-C
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Main features

• Range in primary energy from 10 TeV to
  30 PeV
• energy resolution 10
• angular resolution 1o
• core location lt 2.5 m
• capability to measure independently Ne, Nh, Nm

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Location
It depends on

• Collaboration Institutions
• budget
• altitude (high altitude is preferable)

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Involved Institutions
1. Institute for Nuclear Research, Moscow 2.
MEPhI, Moscow 3. Skobeltsyn Institute, MSU,
Moscow 4. 5.
To be continued... The collaboration is open for
other participants. You are welcome!
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Thank you!