Yu. Stenkin, UHECR'2008 1
On PRISMA project (proposal)On PRISMA project (proposal)
Yuri V. Stenkin
INR RAS
Yu. Stenkin, UHECR'2008 2
The Project aimsThe Project aims
Why PRISMA?PRImary Spectrum Measurement ArrayThe 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 & MotivationHistory & 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 andKASCADE (KArlsruhe Shower Core and Array DEtector) is the best one. 3. The problem still exists.
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EASmethod
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1. The “knee problem”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 explanationsExamples of alternative explanations
энергияШ АЛ
первичнаяэнергия
E 2 E 1недост ающ ая
энергия
E
"и злом "
N
E 0E
Petrukhin StenkinNew processes
knee
Primaryenergy
EASenergy
Missing energy Missing energyPrimaryenergy
Primaryenergy
kneeEASmethodsystematic
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Depth in atmosphere
No of particles
From Hayakawa manual on cosmic ray physics
EAS components equilibrium
Break of equilibrium
Break in attenuation
“knee” in Ne spectrum
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When the break occurs?When the break occurs?
At E~100 TeV / nucleonFor p: 100 TeVFor Fe: 5 PeV (just the knee region)
For details see: Yu.Stenkin, Yadernaya Phys., 71 (2008), 99
This figures are sequences of : Lint= 90 g/cm2 in airthe Earth’s atmosphere thickness =1030 g/ cm2 (depending on altitude)
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2. Existing experiments2. 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 -> KASCADE-GrandeKASCADE -> 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.
- Nobody saw this.
C. R. should consist only of heavy nuclei at 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).
Tibet AS experiment results contradict this hypothesis: they connect the knee with iron primary.
In this case there should be the iron knee at E~1017 eV.
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Compilation of experimental data (astro-ph/0507018)
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KASCADE EAS h-size spectraKASCADE 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 to make a device based on new principles (asymmetrical answer)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 would be the answer.
PRISMAPrism
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New principlesNew 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 MethodsNew Methods
2 new methods have been developed in our Lab.
1st method is based on thermal neutrons “vapour” accompanying EAS
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en-detector designen-detector designPMT
housing
6Li(n,a)3H+4.8 MeV
160,000 photons per capture
ZnS(Ag) is a unique scin-tillator for heavy particlesdetection:
plastic
Scintillator: ZnS(Ag)+6LiF
Similar to that using in neutronimaging technique
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The detector is almost insensitive to single charged particles.But, it can measure the number N of charged particles if N>5.
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Thermal neutron time distributionsThermal neutron time distributionsMulticom Prototype, Baksan Prisma prototype, Moscow
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Another advantage of this detector is a possibility to Another advantage of this detector is a possibility to measure thermal neutron flux of low intensity and its measure thermal neutron flux of low intensity and its variationsvariations
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2d new method:2d new method:The Muon Detector as a 1-layer hadronic calorimeter:The Muon Detector as a 1-layer hadronic calorimeter:
Yu. Stenkin, UHECR'2008 26corem2
jet m2This picture represents a density map as measured by Carpet (left, shown in LOG 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 scale) and by MD (right, linear scale in relativistic particles). (Detector in the center show a particle density of show a particle density of ρρc=8*1.1252/0.5=5800 mc=8*1.1252/0.5=5800 m-2-2. . jet of (26+17)/2=21.5 particles per mjet of (26+17)/2=21.5 particles per m22 in MD. Jet size is very narrow (~1 m) with 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 normal rather low density around it and second: the distance from the EAS core is large enough and equal to 48 m.large enough and equal to 48 m.
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Preliminary Baksan data: hadrons at R=47m
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Preliminary data
Muon/hadron ratio distribution
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Carpet: 400*1m2 en-detectorsgrid with spacing of 5 m
Central muon detector:400*1m2 plastic scinillators
Muon detector tunnels:1200*1m2 plastic scintillators
Outer trigger detectors:4*25*1m2 plastic scintillators
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M-C simulations. CORSIKA 6.501 (HDPM, Gheisha6)
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neutrons: . . . . . . . . . . . . . . . . . . 12 . . . . . 4 . . . . . . . . . . . . . . . . . . . * . . . . . . . . . . . . . . . . . 5 * 21 . . . . . . . . . . . . . . . . . . . . . . . . 4 . . 4 . . . * . . . . . . . . . . . 8 * . . . 4 . 17 7 . . . . . . . . . . . . . . . * . . . . . . . . . . . 10 . . . . . . . . . . . . . . . . . . . . . . 25 . 36 12 . . . 5 . . . . . . . . 7 . . . . 9 5 . . . . . * 14 . . . . . . . . . 5 8 22 * 4 . . . . . . . . . . . . . * 11 17 11 * . . 12 . . . . . . . 16 . . . * . . . 16 * . . . . 4 * . . . . . . . . 19 8 9 12 35 13 13 5 7 . 7 . . . * 14 . 9 . . . . . 13 12 24 25 . 23 11 . . . . . . . . 4 . . . . 17 15 22 29 27 19 4 10 * . . . . . 13 . . 7 15 . . 23 11 25 11 7 . 16 14 . . * . . . . 5 . . . 9 . 13 20 . 5 * . 5 7 . . . . . . . . 4 . . 4 . 10 10 19 . . . . . . . . . . . . 11 . . . 12 . . 7 . . . . . . 18 .
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
M-C simulations. CORSIKA 6.501 (HDPM, Gheisha6)+array
A mapof an eventin neutrons
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M-C
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Main features:Main features:
•Range in primary energy: from ~10 TeV to ~30 PeV•energy resolution: ~ 10%•angular resolution: ~ 1o
•core location: < 2.5 m•capability to measure independently: Ne, Nh, N
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LocationLocation
Collaboration Institutions budget altitude (high altitude is preferable)
It depends on:
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Involved Institutions:Involved Institutions:
1. Institute for Nuclear Research, Moscow2. MEPhI, Moscow3. Skobeltsyn Institute, MSU, Moscow4.5.
To be continued...
The collaboration is open for other participants.
You are welcome!
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Thank you!Thank you!