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EUSO Shower PhenomenologyCosmic Rays detection history:

From golden leaf electroscope to detection from space

EUSO detection of showers: End2End simulation:

First interactionShower developmentFluorescence and Cherenkov signalAtmosphere responseDetector response

Key uncertaintes and Atmosphere Sounding:Benefits from ASDASD domain of applicability

Autonomous Method

Cosmic Rays detection history:

What are cosmic rays?

A short history

What are Extensive Air Showers?

EUSO energy spectrum domain

What are Cosmic Rays?Cosmic Rays (CR) are high-energyparticles of extraterrestrial origin

The astrophysical filed of activityfor particle and nuclear physics

Secondary CR (produced by the primaries in the Earth’s atmosphere) consist of essentially allelementary particles and nulei (both stable and unstable). The most important are

• nucleons, nuclei & nucleides,• (hard) gammas,

• mesons (π±,π0,K±, …, D±,…),• charged leptons (e±, µ±, τ±),• neutrinos & antineutrinos (νe, νµ, ντ).

However the above definition is much wider and includes in fact all stable and quasistableparticles:

• neutrons,• antiprotons & (maybe) antinuclei,• hard gamma rays (λ < 10−12 cm),• electrons & positrons,• neutrinos & antineutrinos,• esotheric particles (WIMPs,

magnetic monopoles, mini blackholes,...).

“Classical” CR are nuclei or ionized atomsranging from a single proton up to an ironnucleus and beyond, but being mostlyprotons (~90%) and α particles (~9%).

Courtesy by V.Naumov

A gold-leaf Bennet-type electroscope(ca. 1880s) manufactured by Ducretet.

Even very well isolated gold-leaf electroscopes are discharged at a slow rate.

… observed by scientists before 1900

J.Elster, H. F.Geitel, C.Wilson investigated this phenomenon and concluded that some unknown source of ionizing radiation existed. Wilson even surmised that the ionization might be

“…due to radiation from sources outside our atmosphere, possibly radiation like Röntgen rays or like cathode rays, but of enormously greater penetrating power.”

1900-1901

Soon after, two Canadian groups, Ernst Rutherford and H. Lester Cooke(1903) at McGill University, and J. C. McLennan and E. F. Burton (1902) at theUniversity of Toronto showed that 5 cm of lead reduced this mysterious radiationby 30%. An additional 5 t of pig lead failed to reduce the radiation further.


1911–1913

Von Victor Franz Hess, studying at the Radium Inst.,Vienna, decided to take the experiment a step furtherand a few thousand meters higher. In 10 balloonascents (with open gondola) reaching altitudes of17,500 ft (about 5.3 km), he found that radiationslowly decreased with height (up to about 700 m) butthen at about 1.5 km it began to rise, until at 5 km itwas over twice the surface rate. Hess concluded:

"The results of the present observations seem to be most readily explained by the assumption that a radiation of very high penetrating power enters our atmosphere from above, and still produces in the lowest layers a part of the ionization observed in closed vessel."

Hess also found that the ionization was similar for day and nigh t time and did not decrease on his flight during a solar eclipse on April 12, 1912; he concluded the sun could not be the main source of the radiation.


Victor Hess won The Nobel Prize in Physics 1936"for his discovery of cosmic radiation" .

Classic references:

• V.F. Hess, Physik. Zeitschr. 12 (1911) 998.• V.F. Hess, Physik. Zeitschr. 13 (1912) 1084.• V.F. Hess, Physik. Zeitschr. 14 (1913) 610.

Background of the slide:

H.E.S.S. (High Energy Stereoscopic System) a next-generation system of Imaging Atmospheric Cherenkov Telescopes for the investigation of cosmic gamma rays in the 100 GeV energy range.


EAS

1938: Pierre Victor Auger, Raymond Maze, Roland Maze and Thérèse Grivet-Meyer positioned their particle detectors high in the Alps. They obtained that two detectors distanced many meters one from another detected the arrival of particles at exactly the same time.

Thus Pierre Auger and collaborators discovered the extensive air showers(EAS), the cascades of secondary particles and nuclei produced by the collision of primary high-energy particles with air molecules. In this way, changing the distance between detectors, Auger could observe particles with energies of about 1 PeV(1015 eV) - ten million times higher than reached so far. *)

________________________________________

*)Of course, this is the today’s estimaton. Auger was not able to estimate the primary energy. Courtesy by V.Naumov

Up to now EAS are detected on the Earth ground

Today the largest ground detector Pierre Auger in Argentina camps will cover ~3000 km2 surface and detect both:

✗Charged particles✗Fluorescent light

A lower energy data suggests a dominance of the protons… •The AGASA data seems to conflict to both Hires and GZK prediction.•There is also a 2 times difference in the flux measurement between Hires and AGASA at low energies!

Hires is a fluorescent detectorAGASA is a charge track detector

Courtesy by C.Lauchaud

Concept ofTUS/TUS2 space free flyer

16x16

PMTs

Fresnel mirror10 rings

Focal distance is 1.5 mField of View is 7.3o

D.V.Skobe lts yn INP Mos cow State Un ive rs ity

Energia Korolev(Rocket Space Corporation)

Luch Syzran SCTB, Russia

JINR, Dubna, Russia

Mexico University , Mexico

Ew ha Womans University Seoul, South Korea

UHECRs measurements fromSpace via detection of fluorescent and Cherenkov light produced by EAS

TUS:

Goal:

1.5 m diameter Fresnel MirrorBackground measurement dozens events per year with E>1020 eV

TUS2: Double TUS

KLYPVE:3.5 m diameter Fresnel Mirror#103 events per year#102 events with E>1020 eV

V. Alexandrov, D. Bugrov, G. Garipov, N.Kalmykov,B.Khrenov, M.

Panasyuk, S.Sharakin, A. Silaev, I. Yashin

V. Grebenyuk,M. Finger, A. Zhuchkova, D. Naumov, Nguen Man

Sat, A. Olshevsky, B. Sabirov,L. Tkatchev, N. Zaikin

O. Saprykin, V. Syromyatnikov

E. Bitkin, S. Eremin, A. Matyushkin, F. Urmantsev

A. Cordero, O. Martinez, E. Morena, C. Robledo,H. Salazar, L. Villaseeor,

A. Zepeda

I. Park NIO KOMPAS, Czech Republic

M. ShonskyTechnical University, Prague, Czech

RepublicJ. Zicha

Even

ts p

er y

ear

TUS

KLYPVE

(1) Double TUS is approved by RosAviaKosmos to fly as a free flyer in 2007.(2) Its mission is basically to test the approach, measure the background and collect a dozen of events per year!(3) We are looking to for a ground based tests/calibration of the detector now.

Mirror moldsection

mold production in JINR/DubnaSpace qualified carbon-plastic Fresnel mirror to be produced@ “Luch” (Syzran)

Orbiting Wide Angle Light-collector (OWL)

Original concept AirWatch (1996)

Improved every year

Two satellites flying in formation

Angular Resolution: 0.2° Energy Resolution: 14%

Aperture: 2X106 km2 ster

Duty Cycle ~12%

Eff. Aperture: 2.3X105 km2 ster

http://owl.gsfc.nasa.gov

EUSO: ISS stationed optics 2 m diameter

Fresnel lenses ±30o FoV 3 years data taking Now end of Phase A


First Interaction Point(anti) neutrinos first depth is about 1.e7 g/cm2 thus the neutrino first interaction point is proportional to the air density

Direct simulation for hadrons according to hadron-air cross-section


Proton 1.e20 eV

Iron 1.e20 eV

Shower developmentCORSIKA QGSJET parametrization called GIL (Greizen-Ilyina-Linsley)

Hybrid MC (UNISIM)


Proton 1.e20 eV

Iron 1.e20 eV

Shower developmentCORSIKA QGSJET parametrization called GIL (Greizen-Ilyina-Linsley)

Hybrid MC (UNISIM)

Energy distribution of charged particles is of importance for both fluorescence anc cherenkov (Varius parametrizations of CORSIKA and like packages)


Fluorescence and Cherenkov signals

Nitrogen excitations studied in past:

Guner, 1964/Buner, 1967Davidson & O’Neil, 1964Kakimoto et al 1996

Is a very exciting topic today:

Nagano et al, 2000 ONLY (Palermo,Paris) Paris low energy spectrometr AIRFLY (Rome) FLASH(SLAC) SLAC MACFLY(CERN) Medium energy (Campaninas) Karlsrhue Cofin (Italy)

( ) ( )TBFATg

11

11 1

, ρρρ += ( ) ( )TBF

ATg

21

22 1760,2

,ρ

ρρ+⋅

=

( ) ( ) ( )0

/)),(),((/,; 21

EEE dxdE

TgTgdxdETEN=

+⋅= ρρργ



Fluorescence energy dependence is reflected into shower age dependence



refractive index as a function of the atmosphere state (T,P,water content, etc)

energy distribution of electrons in showerBack-Scattered in EUSO direction

Both fluoresent and cherenkov signals are delayed due to refractive index… few nsec

( )( )

2

1

22 2

12 1pdN E dzdx n

λ

λ

λπα λβ λ = − ∫

( ) ∫∞=thE

p dEdxEdNXEfdx

XdN )(),(



refractive index as a function of the atmosphere state (T,P,water content, etc)

energy distribution of electrons in showerBack-Scattered in EUSO direction

Both fluoresent and cherenkov signals are delayed due to refractive index… few nsec

© E.Plagnol


Atmosphere response

Light absorbtion/reflectionRayleigh scattering

Mie scattering

Ozone layer absorbtionLowtran7.1 code handles all these and many other effects for us h=0 km

h=100 km

An example from LOWTRAN7.1: a vertical transmission from h to ∞


Detector response

Buffle/Detector GeometryOptics Transport

Focusing

Absorbtion/ReflectionPMT simulation

AFEE

Triggering

EUSO Frequently Used Software

UNISIM PARIS SLASTS.Bottai E.Plagnol D.NaumovS.Bottai

HYBRID METHODS : FULL MC SIMULATION FOR E>Eth , PARAMETRIZATION FOR E<Eth. Good reproduction of fluctuations with Eth=1017eV.

LPM EFFECT INCLUDED

NEUTRINO SIMULATION OF EHE NEUTRINO INTERACTIONS CC+NC

Single cherenkov scattering Clouds simulation

Common features:3D Geometry and Earth Curvature hadron-air initial interactionProduction of fluorescent and cherenkov lightAtmosphere response

Energy distribution of electrons in shower (impact on both fluorescent and cherenkov light)

Easy configurable atmosphere profiles, attenuation, detector parameters

Neurino CC +NC interactions

ESAF light production engine

D.Naumov, EUSO-SDA-015

ESAF reads UNISIM generated files with photons on entrance pupil ESAF is able to read

UNISIM generated files with a shower track

Key uncertaintes and ASD

Key uncertaintes:

Theory of showers @ UHEFluorescence production

Atmosphere Status

Clouds, Earth reliefCherenkov albedo

Detector aging


Key uncertaintes:


Atmosphere Status


Detector aging

(1) Models implemented in CORSIKA give Ne(x) with 20-25% difference(2) Experimental measurements at accelerators are restricted to high Pt while UHECR interact mainly with small Pt


Key uncertaintes:


Atmosphere Status


Detector aging

(1) Precise measurements @ 50-100 MeV energy of electrons is desired (2) The experiments are VERY difficult. Need to measure the spectrum, yield in presence of varius contaminations, its dependence on T,P(3)Today 20-30% are likely to be reduced to 7.5% with forthcoming years


Key uncertaintes:


Atmosphere Status


Detector aging

(1) Need to know the air density, pressure, temperature, attenuation


Key uncertaintes:


Atmosphere Status


Detector aging

(1) Clouds effects are manifold: (2) reflect Cherenkov light(3) absorb and distort the fluorescence light (4) Increase the fluorescence background(5) Earth relief (mountains, hills, holes etc) even in absence of clouds can mimic a different reflection surface


Key uncertaintes:


Atmosphere Status


Detector aging(1) Depends on the scattering surface: Earth or clouds(2) Is about 3-7% over Earth(3) Enhanced up to 60% over clouds


Key uncertaintes:


Atmosphere Status


Detector aging (1) Optics, PMT, filters are aging, loosing their performance(2) Need constantly to monitor the overall detector performace(3) A special monitor device is needed


What do we need to reconstruct energy and Xmax?

Need to know Hmax: two ways

Time difference between photons from the shower maximum and Cherenkov echo (need an external control for scattering surface)

Use the shower signal to decode its development altitude

Fluorescence yield (H)

Atmosphere (+cloud) attenuation (H)


Atmosphere Sounding Device

Purpose and requirements:

Measure atmosphere transparency profile

Detect clouds: their altitude and position, optical depth

3 Options are available:

Lidar typeVisible (opaque)cloud: Detectionof presence

(Integration time)

Sub-visible cloud:Presence detectionminimum OD value(Integration time)

Sub-visible cloud:Min. measurableOD value

(Integration time)

Sub-visible cloud:OD resolution(integration time)

AltitudeResolution(m)

ASD1: PRN-cw lidar Yes (0.01 sec) 0.2 N.A. N.A. 150ASD2: 1-wavelength lidarYes (0.01 sec) 0.05 (max 5 sec) 0.12 (max 5 sec)25% (max 5 sec) 150ASD3: 3-wavelength lidarYes (0.01 sec) 0.05 (max 5 sec) 0.12 (max 5 sec)10% (max 5 sec) 150


Atmosphere Sounding Device

What we could gain with ASD:

Recover that there is 30% of clear sky (no correction)

Try to recover showers with no maximum detected (due to clouds)

Apply corrections for showers impacting on the clouds

h>10 km 1.9%17.9%3.3%4.8%7< h < 10 0.5% 4.2% 3.8%4.2%3 < h < 7 0.7%2.43%3.21%4.9%h < 3 km 29.5%6.6% 5.8%14.1%TOVs+ OD < 0.1 0.1<OD<2 1<OD<2 OD > 2

ASD (LIDAR) difficulties: Precise pointing device:

EUSO Triggers ASD and reports microcell triggeredEUSO or ASD electronics solves X,Y ambiguity of microcell output (reads X, Y or 4 PMT)

100 shots in 1 secondSearch for a cone around the shower track, thus sensitive to homogenous wide coverage of clouds

70% of cloudy sky DOES NOT MEAN the same fraction of showers impacting clouds:

Dense clouds are lowlying and affect only vertical showers

Shower autonomous method

Use only fluorescence

5km

20 km

Time development of two horizonthal showers. Nmax/Ntot ~ ρ(h)

Shower autonomous method

Rec vs Sim Correlations Relative error

Altitude of Shower Maximum Reconstruction

Next talk is devoted to EUSO Reconstruction

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