Air Cherenkov Methods in Air Cherenkov Methods in Cosmic Rays: A Review and Cosmic Rays: A Review and

Some HistorySome History

A.S. Lidvansky,A.S. Lidvansky,

Institute for Nuclear Research, Institute for Nuclear Research, MoscowMoscow

The Vavilov-Cherenkov radiation The Vavilov-Cherenkov radiation of high energy cosmic rays in air:of high energy cosmic rays in air:

Only extensive air showers (EAS) can Only extensive air showers (EAS) can produce sufficient signal to be observed produce sufficient signal to be observed against the night sky background against the night sky background

Observations are possible only in clear Observations are possible only in clear moonless nights (no more than 10% of moonless nights (no more than 10% of calendar time) calendar time)

There are three different lines of research There are three different lines of research in this field differing in both energy range in this field differing in both energy range and instrumentation and instrumentation

All these three lines of research were All these three lines of research were initiated by a single man! initiated by a single man!

(A.E. Chudakov) (A.E. Chudakov)

Air Cherenkov Methods

1. Investigations of Extensive Air Showers

(> 1015 eV)

2. Very High Energy Gamma Ray Astronomy

(1011-1013 eV)

3. Experiments with Reflected

CherenkovLight (>1018 eV)

Two outstanding “CH”sTwo outstanding “CH”s

P.A. Cherenkov (1904-1990) A.E. Chudakov (1921-2001)

A.E. Chudakov about A.E. Chudakov about P.A. Cherenkov:P.A. Cherenkov:

““Always a modest individual, he was Always a modest individual, he was extremely scrupulous not to pretend to be extremely scrupulous not to pretend to be involved in the developing applications just involved in the developing applications just because of his contribution to the effect’s because of his contribution to the effect’s discovery…”discovery…”

A.E. Chudakov, A.E. Chudakov, Pavel Alexeevich Cherenkov (Obituary), Pavel Alexeevich Cherenkov (Obituary),

Physics Today, December 1992 Physics Today, December 1992

““He even may have been avoided using He even may have been avoided using the Cherenkov technique in his own the Cherenkov technique in his own experiments…”experiments…”

A.E. Chudakov, A.E. Chudakov,

Pavel Alexeevich Cherenkov (Obituary), Pavel Alexeevich Cherenkov (Obituary), Physics Today, December 1992 Physics Today, December 1992

However, in developiong the air Cherenkov However, in developiong the air Cherenkov technique Chudakov had some predecessors:technique Chudakov had some predecessors:

P. Blackett in 1948 first discussed the P. Blackett in 1948 first discussed the possibility to detect the Cherenkov possibility to detect the Cherenkov radiation of extensive air showers radiation of extensive air showers It was first detected by Galbraith and Jelly It was first detected by Galbraith and Jelly in 1952: in 1952:

1.1. W. Galbraith and J. V. Jelley, Nature, W. Galbraith and J. V. Jelley, Nature, 171171, 349 (1953)., 349 (1953).

2.2. J. V. Jelley and W. Galbraith, Phil. J. V. Jelley and W. Galbraith, Phil. Mag., Mag., 4444, 619 (1953)., 619 (1953).

Chudakov's experimental setup in Pamirs Chudakov's experimental setup in Pamirs experimentsexperiments (1953-1957)(1953-1957)

Investigations of Extensive Air Investigations of Extensive Air ShowersShowers

In these experiments, carried out in the In these experiments, carried out in the Pamirs Mountains, the idea of calorimetric Pamirs Mountains, the idea of calorimetric measurements of the cascade energy by measurements of the cascade energy by recording its Cherenkov radiation was recording its Cherenkov radiation was realized. Experimental ratio between the realized. Experimental ratio between the cascade energy and the observed number cascade energy and the observed number of particles was measured for the first of particles was measured for the first time. The energy spectrum of primary time. The energy spectrum of primary cosmic rays was measured in a wide cosmic rays was measured in a wide range.range.

Modern Cherenkov Air Shower Array (Tunka)

Remote Detector

Basic Integral Detectors

Pulse Shape Detectors

Panorama of the Tunka array Panorama of the Tunka array (675 m above sea level)(675 m above sea level)

Pulse shape detector of Cherenkov lightPulse shape detector of Cherenkov light

QUASAR-370 light receiver

Some results of the Tunka arraySome results of the Tunka array

pp

Fe

Shower maximum depth Differential energy spectrum

CASA-BLANCACASA-BLANCA: : Cherenkov array Cherenkov array

BLANCABLANCA(144 detectors with an(144 detectors with an average separation average separation

of 35-40 m) and CASA of 35-40 m) and CASA air shower array (a air shower array (a

lattice of 900 scintillation lattice of 900 scintillation detectors with a step detectors with a step

of 15 m ).of 15 m ).

Cherenkov and fluorescence data on cosmic ray composition

A A Station of Station of the the Yakutsk EAS ArrayYakutsk EAS Array

1 .5 m to C en tre r

5 5

C eren k o v lig h td e tec to r

S c in tilla tio nd e tec to r 2 m 2

S in ch r. re c iv.

A plan of the location of detector stations of the Yakutsk EAS Array

The Cherenkov Light Detector of Yakutsk EAS array

Estimation of shower energy E0

The calorimetric method The relation between parameters S300 or S600 and primary particle energy E0 for showers close to the vertical has been determined by the calorimetric method. For the average showers with different S300 or S600 E0 is estimated as the sum separate a components:

E0 = Ei + Eel + Eμ+ Eμi + Eν + Eh

Ei = k is the energy lost by a shower over the observation level. It is

estimated by measurements of total Cerenkov light flux , and

k = 2.16104 / (0.37 + 1.1(Xm /1000) in the interval of waves 300-

800nm In view of mean atmospheric transmittance

Eel = 2.2106NsN is the energy conveyed below the array level. It is

estimated by the attenuation length N of the number of charged particles Ns through the atmosphere depth

E = N is the energy of the muon component. It is estimated by the total

number of muons N and average energy on one muon = 10.6109 eV

Ei + E = 0.76E are the energy of muons losses on ionization and the

neutrino

Eh = 0.06Ei is the energy on nuclear reactions in the atmosphere.

Red components are added on the basis of model calculation results.

For E0 1019 eV : Ei / E0 74%; Eel / E0 15%; Eμ / E0 3.6%;

(Eμi + Eν + Eh) / E0 7.4%

Lateral distribution of EAS Cerenkov light, <30, 1015 <E0 < 31019 eV

RRQR )(2

Q(R) = Q150((62+R)/212)-1((200+R)/(350))1-m,

m = (1.150.05) + (0.300.06)log(Q150)

10 1001E17

1E18

1E19

E0=(5.66 + 1.4)*1017

*(S300/10)(0.94 + 0.02)

E0,

eV

S300

(0o), m-2

Ratio between shower energy E0 and S300(0º) determined by the calorimetric method

EO = (5.66 1.4)1017(S300(0)/10)0.94 0.02

VHE Gamma Ray AstronomyVHE Gamma Ray Astronomy

The gamma ray telescope constructed by The gamma ray telescope constructed by Chudakov was the first instrument ever Chudakov was the first instrument ever specially designed for observations of specially designed for observations of gamma rays from space. The method was gamma rays from space. The method was suggested in a paper by suggested in a paper by G.T. Zatsepin and G.T. Zatsepin and A.E. ChudakovA.E. Chudakov, «On the methods of , «On the methods of searching for local sources of high energy searching for local sources of high energy photons», photons», J. Exp. Theor. Phys.,J. Exp. Theor. Phys., vol. 41 vol. 41 (1961), p. 655 (In Russian).(1961), p. 655 (In Russian).

First Gamma-Ray TelescopeFirst Gamma-Ray Telescope

Katsively, Katsively, CrimeaCrimea

(1960- (1960- 1963)1963)

One Cherenkov light receiver of the first One Cherenkov light receiver of the first gamma ray telescopegamma ray telescope

Four mirrorsFour mirrors

were installed inwere installed in

the season 1960,the season 1960,

and all twelveand all twelve

mirrors weremirrors were

used in the used in the

remainingremaining

seasons 1961, seasons 1961,

1962, and 1963. 1962, and 1963.

Crab Nebula is the first detected object and the Crab Nebula is the first detected object and the ‘standard candle’ of‘standard candle’ of

the VHE gamma ray astronomythe VHE gamma ray astronomy

First Gamma-Ray TelescopeFirst Gamma-Ray Telescope

The negative result of Chudakov’s The negative result of Chudakov’s experiment was important in one respect:experiment was important in one respect:

It was generally believed at that time that the It was generally believed at that time that the synchrotron radiation in the Crab Nebula is due synchrotron radiation in the Crab Nebula is due to electrons of secondary origin (produced by to electrons of secondary origin (produced by pions generated in proton-proton collisions via pions generated in proton-proton collisions via

e decay). e decay). If so, one would expect a significant gamma ray If so, one would expect a significant gamma ray flux from decays of neutral pions. flux from decays of neutral pions. The upper limit obtained by Chudakov was a The upper limit obtained by Chudakov was a proof of direct acceleration of electrons in proof of direct acceleration of electrons in the Crab Nebula (and other sources).the Crab Nebula (and other sources).

The idea of air fluoresence experiments was also put The idea of air fluoresence experiments was also put forward by A.E. Chudakovforward by A.E. Chudakov

V.A.Belyaev &V.A.Belyaev &

A.E. Chudakov, A.E. Chudakov,

Ionization glow of airIonization glow of air

and its possible use forand its possible use for

air shower detection, air shower detection,

Bulletin of USSRBulletin of USSR

Academy ofAcademy of

Sciences, Phys.Sciences, Phys.

Ser.,Ser., 1966, vol. 30, 1966, vol. 30,

no. 10, p. 1700no. 10, p. 1700

EUSO: Extreme Universe Space ObservatoryEUSO: Extreme Universe Space Observatory

Accommodation onboard the ISS

Multiple mirror-telescopes

Stereoscopic observations Stereoscopic observations in VHE astronomyin VHE astronomy

French telescope CAT French telescope CAT (Perinei mountains)(Perinei mountains)

TelescopeTelescopeHegra at Canary Hegra at Canary

IslandsIslands

CT-3CT-3

CT-4CT-4

Australian-Australian-Japanese Japanese telescope telescope Cangaroo IICangaroo II

Stereoscopic CANGAROO III Stereoscopic CANGAROO III telescope (Project)telescope (Project)

CANGAROO III under construction CANGAROO III under construction (July 2003)(July 2003)

HESSHESS ( (HHigh igh EEnergy nergy SStereoscopic tereoscopic SSystem) ystem) air Cherenkov telescope in Namibiaair Cherenkov telescope in Namibia

One HESS reflectorOne HESS reflector

VERITASVERITAS ( (VVery ery EEnergetic nergetic RRadiation adiation IImaging maging TTelescope elescope AArray rray SSystem)ystem)

An array of sevenAn array of seven

10m - 12m optical10m - 12m optical

reflectors forreflectors for

gamma-raygamma-ray

astronomy in theastronomy in the

GeV - TeV energyGeV - TeV energy

range range

One Veritas reflectorOne Veritas reflectorThe new arrayThe new arraydesign will bedesign will bebased on thebased on thedesign of thedesign of theexisting 10mexisting 10mgamma-raygamma-raytelescope of telescope of the Whipple the Whipple Observatory.Observatory.

PM tube camera of Veritas PM tube camera of Veritas (499 pixels)(499 pixels)

The fullThe full

field offield of

view is 3.5view is 3.5°. °.

New 17 m MAGIC telescope. New 17 m MAGIC telescope. Plans…Plans…

… … and realityand reality

MAGIC MAGIC under under constructionconstruction

MAGIC siteMAGIC site

Magic I is operational, Magic I is operational, Magic II is planned Magic II is planned

Global coverage of most powerful VHE Global coverage of most powerful VHE Cherenkov telescopesCherenkov telescopes

VERITAS

MAGIC

HESSCANGAROO-3

TeV Gamma Ray Sky: ~ 10 galactic TeV Gamma Ray Sky: ~ 10 galactic and 8 extragalactic sourcesand 8 extragalactic sources

Almost all sources are identified, their number increases every year

Classes of objects in TeV Catalog:Classes of objects in TeV Catalog:

AGNAGN

Radio GalaxyRadio Galaxy

Starburst GalaxyStarburst Galaxy

Supernova RemnantsSupernova Remnants

Binary Source Binary Source

OB AssociationOB Association

Multi-wave observations of Mrk 421 Multi-wave observations of Mrk 421

AGN jet emission

adopted from:K. Mannheim(1998)

Cherenkov astronomy at solar Cherenkov astronomy at solar power plantspower plants

An example of solar power plant used as an air An example of solar power plant used as an air Cherenkov telescope (STACEE)Cherenkov telescope (STACEE)

STACEESTACEE: : SSolar olar TTower ower AAtmospheric tmospheric CCherenkov herenkov

EEffect ffect EExperimentxperiment (New Mexico)(New Mexico)

Secondary mirror Secondary mirror and detecting and detecting systemsystem

Solar II experiment (Barstow, CA)Solar II experiment (Barstow, CA)

CheSS Project: Japanese telescope CheSS Project: Japanese telescope SUBARU (Hawaii)SUBARU (Hawaii)

Optical-infrared Optical-infrared telescope with a 8.3 m telescope with a 8.3 m mirror at 4000 m a.s.l.mirror at 4000 m a.s.l.CheSSCheSS ( (CheCherenkov renkov light detecting light detecting SSystem ystem on on SSubaru) is aimed to ubaru) is aimed to detect 10 GeV gamma detect 10 GeV gamma rays rays

Chudakov’s suggestion of experiments with Chudakov’s suggestion of experiments with snow-reflected Cherenkov radiation:snow-reflected Cherenkov radiation:

A.E. Chudakov, A possible method to A.E. Chudakov, A possible method to detect EAS through Cherenkov radiation detect EAS through Cherenkov radiation reflected from snowy ground surface,reflected from snowy ground surface,

in in ““Experimental methods of studying Experimental methods of studying cosmic rays of ultra-high energies”, cosmic rays of ultra-high energies”, Proc. Proc. of All-Union Symposium, Yakutsk, 1of All-Union Symposium, Yakutsk, 1972, 972, pp. . 69.69.

Original Chudakov’s suggestion was Original Chudakov’s suggestion was never implementednever implemented

Chudakov in his suggestion had in mind Chudakov in his suggestion had in mind the airplane experiment during polar nightthe airplane experiment during polar night

Some attempts were made to observe Some attempts were made to observe reflected EAS signal in mountainsreflected EAS signal in mountains

Now the idea of a fixed balloon is realized Now the idea of a fixed balloon is realized and the project of an experiment with a and the project of an experiment with a high-altitude balloon is under development high-altitude balloon is under development

Experiment SPHERE-1 with a Experiment SPHERE-1 with a fixed balloonfixed balloon

SPHERE-2 design and operationSPHERE-2 design and operation

Results of the SPHERE-1 detectorResults of the SPHERE-1 detector

BACH: BBACH: Balloonalloon A Airir CH CHerenkoverenkov experiment experiment

Direct measurements of the flux ofiron nuclei with energy threshold of 2.2.1013 eV

New ideas in air Cherenkov technique application: New ideas in air Cherenkov technique application: Neutrino physics and astronomyNeutrino physics and astronomy

Earth-skimming and Earth-skimming and mountain-traversing mountain-traversing neutrinos neutrinos

NuTel collaboration prepares NuTel collaboration prepares an experiment at Hawaii an experiment at Hawaii

Window of opportunityWindow of opportunity

Conventional detector UHECR detector?

NuTel

Combination of Cherenkov and Combination of Cherenkov and fluorescence techniquesfluorescence techniques

Two outstanding “CH”sTwo outstanding “CH”s

P.A. Cherenkov (1904-1990) A.E. Chudakov (1921-2001)

Conclusions:Conclusions: The radiation first discovered by P.A. The radiation first discovered by P.A. Cherenkov serves as a basis for a variety Cherenkov serves as a basis for a variety of methods in cosmic ray studiesof methods in cosmic ray studies

Among them, air Cherenkov methods form Among them, air Cherenkov methods form a separate area with several lines of a separate area with several lines of researchresearch

Nearly all of the latter were first developed Nearly all of the latter were first developed or suggested by A.E. Chudakov whose or suggested by A.E. Chudakov whose ideas and experimental skill laid the ideas and experimental skill laid the foundation for present-day progress foundation for present-day progress