particle physics with space detectorspeople.roma2.infn.it/~morselli/astroparticelleroma1.pdf ·...

Aldo Morselli INFN, Sezione di Roma 2 & Università di Roma Tor Vergata 1

Particle Physics withSpace Detectors

Aldo MorselliINFN, Sezione di Roma 2 &

Università di Roma Tor Vergata

Roma, 18 Marzo 2004

Corso di Astroparticelle Anno 2003-2004

Cosa si vuole studiare?• Cielo nei raggi gamma• Antimateria nell'Universo• Brillamenti e tempeste solari• …….

Gamma ray attenuation

Gamma rayattenuation (2)

Relation between the temperatureof a black body and the frequencyat which most of the energy isemitted

Transparency of the atmospherefor radiation of differentwavelengths.The solid line show the heightabove sea-level at which theatmosphere becomes tranparent.

EGRET:the detector

Energy range: 20 MeV - 30 GeVWeight: 1820 KgPower: 160 WField of view: 0. 5 srDead Time: 100 msEffective Area (@1GeV) 1200 cm2

Angular resolution 5.8o

(@100MeV)

Sensitivity 0.1 GeV 5x10-8

for point 1 GeV 1x10-8

sources 10 GeV 2x10-8

(ph cm-2 s-1)*

EGRET – Principle ofgamma ray detection

A γ_ray which enters the top of the EGRETinstrument will pass undetected through the largeanticoincidence scintillator surrounding the sparkchamber and has a probability 33% of convertinginto an electron_positron pair in one of the thintantalum (Ta) sheets interleaved between the 28closely spaced spark chambers in the upper portionof the instrument.Below the conversion stack are two 4 x 4 arrays ofplastic scintillation detector tiles spaced 60 cm apartwhich register the passage of charged particles. If thetime_of_flight delay indicates a downward movingparticle which passed through a valid combination ofupper and lower scintillator tiles, and theanticoincidence system has not been triggered by acharged particle, the track information is recordeddigitally. In this manner, a three dimensional pictureof the path of the electron_positron pair is measured.The energy deposition in the NaI(Tl) Totalabsorption Shower Counter (TASC) locateddirectly below the lower array of plastic scintillatorsis used to estimate the photon energy.

Elements of a pair-conversion telescope

• photons materialize into matter-antimatter pairs: Eγ --> me+c2 + me-c2

• electron and positron carry information about the direction, energy and polarization of the γ-ray

(energy measurement)

Energy loss mechanisms:

Fractional energy loss for e+ and e- in leadPhoton total cross sections

Interaction of electrons and photons with matter

MultipleScattering

0.1 1 10

0.15Xo(deg)0.07Xo(deg)0.05Xo(deg)

r dist

)E(GeV)

0.1 1 10

0.15Xo(deg)0.07Xo(deg)0.05Xo(deg)

r dist

E(GeV)

the deep sky

EGRET All Sky Map (>100 MeV)CygnusRegion

Geminga

CosmicRay

InteractionsWith ISM

LMCPKS0528+13

4PKS 0208-

PSRB1706-

Third EGRET Catalog

Binary system formed by a black hole and a companion star

Aldo Morselli INFN, Sezione di Roma 2 & Università di Roma Tor Vergata 18a rotating black hole in an accretion disk

Aldo Morselli INFN, Sezione di Roma 2 & Università di Roma Tor Vergata 19Models for High Energy Emission: A cartoon

Astroparticelle :Usare la fisica delle particelle per capire la struttura ed evoluzione dell'Universo(e/o viceversa)

What is the Universe made of ?observed

expectedfromluminous disk

M33 rotation curve

5 10 R(kpc)

v (km/s)

What is the Universe made of ?We know that there isdark matter, which isneeded to explain thedynamics of stars inGalaxies and of galaxiesin clusters. This darkmatter does notinteract with light, andwe do not know wichparticles is made of.

• The peripheral stars of the galaxy M63 rotate around the center so fastthat they would fly away in space without the presence of additional massinside the galaxy. This is indirect evidence for the presence of dark matter

Dark matter problemThe LSP can be a good candidate also for the solution of the Dark Matter Problem.

Experimentally in spiral galaxies the ratio between the matter density and the Critical densityΩ=ρ/ρcrit is : (ρcrit~1.5 g cm-2 )

Ω lum ≤ 0.01but from rotation curves must exist a galactic dark halo of mass at least:

Ω halo ≥ 0.1

from gravitational behavior of the galaxies in clusters the Universalmass density is : Ω halo ≅ 0.2 ÷ 0.3from structure formation theories and analyses of the CMB:

Ω halo ≥ 0. 3

but from big bang nucleosinthesis and analyses of the CMB the Barionic matter cannot be more

then: 0. 03 ≤ Ω B ≤ 0. 05 (astro-ph/0106035)

So the best candidate seems to be a Weakly Interacting Massive Particles (WIMP), but neutrinoswith mass less then 30 eV do not reproduce well the observed structure of the Universe, so theLSP is a good candidate to solve the Dark matter problem.

What is the Universe made of ? Bright stars: 0.5% Baryons (total): 4.4% ± 0.4% Matter: 27% ± 4% Cold Dark Matter: 22.6% ± 4% Neutrinos: < 0.15% Dark Energy: 73% ± 6% h=0.71 + 0.04 - 0.03

WMAP+SN+HSTastro-ph/0302209

astro-ph 0007333

Dark Energy

BaryonsCold Dark Matter

Candidates for Galactic Dark Matter• Massive Compact Halo Objects (MACHOs)

• Low (sub- solar) mass stars. Standard baryonic composition.• Use gravity microlensing to study.• Could possibly account for 25% to 50% of Galactic Dark Matter.

• Neutrinos• Small contribution if atmospheric neutrino results are correct, since mν< 1eV.• Large scale galactic structure hard to reconcile with neutrino dominated dark matter

• Weakly Interacting Massive Particles ( WIMPs)• Non- Standard Model particles, ie: supersymmetric neutralinos• Heavy (> 10GeV) neutrinos from extended gauge theories.

SupersymmetryParticle Sparticle

For unbroken supersymmetry they shoul be degenerate in mass

Sparticle have not be found at accelerators so far

Supersymmetry is brokenSupersymmetry breaking schemes:1) gravity-mediated scenarios2) Gauge mediated scenarios3) Anomaly mediated scenarios

Andamento delle Costanti di Accoppiamento

Andamento delle costanti di accoppiamento in funzione dell'energia per il modello Standard delleparticelle elementari e per il Minimo Modello Supersimmetrico Minimale

Neutralino WIMPs

Assume χ present in the galactic halo• χ is its own antiparticle => can annihilate in galactic haloproducing gamma-rays, antiprotons, positrons….• Antimatter not produced in large quantities through standard processes(secondary production through p + p --> p + X)• So, any extra contribution from exotic sources (χ χ annihilation) is aninteresting signature• ie: χ χ --> p + X• Produced from (e. g.) χ χ --> q / g / gauge boson / Higgs boson andsubsequent decay and/ or hadronisation.

Supersymmetry introduces free parameters:In the MSSM, with Grand Unification assumptions, the masses and couplings of the SUSY particles as

well as their production cross sections, are entirely described once 5 parameters are fixed:

• M1/2 the mass parameter of supersymmetric partners of gauge fields (gauginos)

• µ the higgs mixing parameters that appears in the neutralino and chargino mass matrices

• m0 the common mass for scalar fermions at the GUT scale

• A the trilinear coupling in the Higgs sector

• tang β = v2 / v1 = <H2> / <H1> the ratio between the two vacuum expectation values of theHiggs fields

LEPExperimental

lower limit on themass of the

lightest neutralinoassuming MSSM

(Minimal StandardSupersymmetric Model)

Mχ > 50 GeV

Limits on Supersymmetry already established

hep-ph/0004169

SuperSymmetric Dark MatterPossible signature:Gamma Rayfrom NeutralinoAnnihilation

Annihilation at rest:bump around Neutralino mass

10 GeV 100 GeV

Diffuse background

A=pseudoscalarχ±=charginoχ0 =neutralinoH=Higgs boson

Total photon spectrum from the galactic center from χχ ann.

γ lines50 GeV

300 GeV

Bergstrom et al.

Infinite energy resolution

With finite energy resolution

• Two-year scanning mode

HALO SUBSTRUCTURE

A.Font and J.Navarro, astro- ph/ 0106268

600 kpc

Milky Way

Contours of photons intensity in units of 10-5 ph cm-2 sec-1 sr-1 for Eγ>1GeV, after subtraction of “best estimate of Galactic Diffuse model. Data indicates presence of a galactic halo (Dixon et al. 1998).

Search for the Nature of Dark Matter

Search for the Nature of Dark Matter• The EGRET team (Mayer-Hasselwander et al, 1998) have seen a convincing signal for a strong excess ofemission from the galactic center, with I(E) x E2 peaking at ~ 2 GeV, and in an error circle of 0.2 degreeradius including the position l = 0o and b = 0o. In their paper it was speculated that among other possiblecauses, this excess could be due to the continuum γ-ray spectrum from Wimp annihilation. With thedramatically improved angular resolution and effective area of GLAST, this effect should become both morelocalized and pronounced if it is a Galactic Center phenomenon.

EGRET Map ofGalactic Center

Region

EGRET data & Susy models

~2 degrees around the galactic center

EGRET dataA.Morselli, A.Lionetto, A.Cesarini, F.Fucito, P.Ullio, 2002

Annihilation channel b-bbarMχ =50 GeV

background model(Galprop)WIMP annihilation (DarkSusy)Total Contribution

Nb=1.82 1021

Nχ=8. 51 104

Typical Nχ values:NFW: Nχ = 104

Moore: Nχ = 9 106

Isotermal: Nχ = 3 101

~2 degrees aroundthe galactic center,2 years data

(Galprop)(one example from DarkSusy)

GLAST Expectation & Susy models

astro-ph/0305075

Differential yieldfor each annihilationchannel

WIMP mass=200GeV

total yields

yields not due to π0decay

Differential yieldfor b bar

neutralino mass

region where0.13 < ΩCDM.h2 < 1

GLAST sensitivity (5 σ) for aneutralino density Nχ of 104 ina ΔΩ=10-5 sr region around thegalactic center

Minimal Supersymmetric Standard Model with:A0 = 0, µ > 0, mt =174 GeV

Typical Nχ values for ΔΩ=10-5 sr :NFW: Nχ = 104

Moore: Nχ = 9 106

A.Cesarini, F.Fucito, A.Lionetto, A.Morselli, P.Ullio, astro-ph/0305075 v.2

Estimated reaches with GLAST

region where0.09 < ΩCDM.h2 < 0.13

if GLAST do not see Supersymmetrythis region is excluded for a NFW halo mh0 <114.3 GeV GeV

region where0.13 < ΩCDM.h2 < 1

GLAST sensitivity (5 σ) for aneutralino density Nχ of 104

in a ΔΩ=10-5 sr region aroundthe galactic center

Minimal Supersymmetric Standard Model with:A0 = 0, µ > 0, mt =174 GeV

Typical Nχ values for ΔΩ=10-5 sr :NFW: Nχ = 104

Moore: Nχ = 9 106

updated from A.Cesarini, F.Fucito, A.Lionetto, A.Morselli, P.Ullio, astro-ph/0305075

Estimated reaches with GLAST

region where0.09 < ΩCDM.h2 < 0.13

if GLAST do not see Supersymmetrythis region is excluded for a NFW halo mh0 <114.3 GeV GeV

Positron Ratio

(Phys.Rev. D59 (1999) astro-ph 98008243)

•Background from normal secondary production

•Signal from ~ 300 GeV neutralino annihilations

Caprice94 data from ApJ , 532, 653, 2000

(ApJ 493, 694, 1998)

• Caprice98 data from XXVI ICRC, OG.1.1.21, 1999

Signal from neutralino annihilations

Background from normal secondary production

PAMELAPOSITRONSexpectation

Secondary production

‘Leaky box model’Secondary production‘Moskalenko + Strongmodel’ withoutreacceleration

Primary productionfrom χ χannihilation

(m(χ) = 336 GeV)Primary production

for 3 years of operation

Secondary production

Background from normal secondary production

Signal from 964 GeVneutralino annihilations ( astro-ph 9904086)

Mass91 data from XXVI ICRC, OG.1.1.21 , 1999

Caprice94 data from ApJ, 487, 415, 1997

Caprice98 data fromApJ, 561, (2001), 787. astro-ph/0103513

Distortion of the secondary antiproton flux induced by a signal from a heavy Higgsino-like neutralino.

Particles and photons aresensitive todifferent neutralinos.Gaugino-like particles aremore likely to produce anobservable flux of antiprotonswhereas Higgsino-likeannihilations are more likely toproduce an observablegamma-ray signature

∆ BESS data from Phys.Rev.Lett, 2000, 84, 1078

AMS data : preliminary

BESS 00

PAMELA: Cosmic-Ray AntiparticleMeasurements: Antiprotons

Secondary production(upper and lower limits)Simon et al.

Secondary production(CAPRICE94-based)Bergström et al.

Primary productionfrom χχ annihilation(m(χ) = 964 GeV)

RaggiCosmici

MASS Matter Antimatter Space Spectrometer

The CAPRICE 94 flight

48 cmThe TS93 and CAPRICE silicon-tungsten imaging calorimeter.

CAPRICE 94

CAPRICE98

Proton energyspectrumat the top ofatmosphere

The heliumenergyspectrum atthe top ofatmosphere

CAPRICE98

SilEye on MIR Space Stationwizard.roma2.infn.it

The complete detector

NINA 2 on MITA

Launch of NINA 1 : 10/8/1998Launch of NINA 2 : 15/7/2000More info: http://wizard.roma2.infn.it

The basic silicon detectorThe basic silicon detector

The NINA instrumentNINA2-MITALaunch

a silicon wafer 6x6 cm2 , 380 µm thick with 16 strips, 3.6 mm wide in two orthogonal views X -Y

Sampex, Imp 8, NINA

GOES 7, 8,

PAMELA

RESURS-DK1 SatelliteMass: 10500 KgElliptical Orbit 70.4° incl.300-600 Km altitudeLaunch: December 2002Mission Life > 3 Yr.Launcher : Soyuz-TM

Physics Objectives♦ AntiProton spectrum : 80 MeV - 180 GeV♦ Positron spectrum : 50 MeV - 200 GeV♦ Search for Antinuclei♦ e+ + e- up to 1 TeV

♦ Multi TeV electrons♦ Solar and Trapped Cosmic Rays♦ Solar Energetic Particles♦ Long Term Solar Modulation♦ Radiation Belts Transient Phenomena

Bare Mass: 450 KgTotal Mass: ~750 KgPower: 350 WGF: 21 cm2srMDR: 740 GV/c

Separating pfrom e-

TOF : Time of Flight (S1) Pamelaantiproton

TRD : Transition Radiation Detector

TOF : Time of Flight (S2)

Magnetic Spectrometer

TOF : Time of Flight (S2)

Silicon Calorimeter

positron

S4 and Neutron detectors

Tracker(s)SiliconStripDetectors

PamelaTRDTRD

TRKTRK

TOFTOF

ANTIANTI

CALOCALOMassa del rivelatore 440 KgPotenza 355 WMDR – 770 GV

Protoni 80 MeV – 700 GeVAntiprotoni 80 MeV –190 GeVElettroni 50 MeV – 2 TeVPositroni 50 MeV - 270 GeVNuclei < 700 GeV/nLimite per Antinuclei 10-8

TRDTRD

• Threshold detector.

• 9 radiator planes (carbon fiber)and straws tubes (4mm diameter)filled with Xe-CO2 mixture.

• e/p separation (E > 1 GeV/c) atlevel of 10-2.

TRKTRKSi Tracker + magnet

• Permanent magnet B=0.4T

• 6 planes double sided Si strips300 µm thick

• Spatial resolution ~3µm

• MDR = 740 GV/c

TOFTOF

Time-of-flight

• Level 1 trigger

•Albedo discrimination

• dE/dx (Z)

• particle identification (up to1GeV/c)

• Plastic scintillators + PMTs

• Time Resolution ~ 110 ps

ANTIANTI

Anticoincidence system

• Defines tracker acceptance

• off-line or on-line veto

• Plastic scintillators + PMTs

S4 S4 NDND

S4 and Neutron detectors

• Extend the energy range forprimary protons and electronsup to 10 TeV

•Plastic Scintillator. Trigger forneutron detector

• 36 3He counters in apolyetilen moderator

PAMELA DETECTOR

CALOCALO

Si-W Calorimeter

• Imaging Calorimeter :reconstructs shower profile.

Si-X / W / Si-Y structure

22 W planes 16.3 X0 / 0.6 l0

• rejection power e+/p and p/e-

at level of 10-4 ~ 10-5

• Energy Resolution for e±

ΔE/Emeasured < 5% ( 20-200 GeV )selftriggeringG.F.~ 470 cm2 srElectrons up to 2 TeV

New Detector Technology• Silicon strip detector

Strip-shapedPN diode

50-500micron wide

300-500micron thick

VLSI amplifier

Stable particle tracker that allows micron-level tracking of gamma-rays

Well known technology in Particle Physics experiments.Used by our collaboration in balloon experiments (MASS, TS93, CAPRICE),on MIR Space Station ( SilEye) and on satellite (NINA)

Silicon Strip Detector Principle

CALORIMETER

SPECTROMETER

ANTICOINCIDENCE

MASS THERMAL MODELMASS THERMAL MODELFLIGHT MODEL FLIGHT MODEL (CERN TEST BEAM)(CERN TEST BEAM)

10 GeV e-

10 GeV p

The Resurs-DK1 satelliteCarrier rocket: SOYUZ

PAMELA Launch

Presurizedcontainer withPAMELAin operatingpositionPAMELA in

launchingposition

field of view

Expected Date of launch :end of 2004

ANTIPROTON

AMSLancio: 2007Durata: 3 anni

Protoni fino ad alcuni TeVAntiprotoni fino a 200GeVElettroni fino al TeVPositroni fino a 200 GeVNuclei fino ad alcuni TeVAntiNuclei fino al TeVγ fino a 100 GeVIsotopi leggeri fino a 20GeV

Altezza: 320-390 KmAltezza: 320-390 KmInclinazione 51.7Inclinazione 51.7°°

Aldo Morselli INFN, Sezione di Roma 2 & Università di Roma Tor Vergata 71AGILE

AntiCoincidence PhotomultipliersTop: 0.5cm plastic scintillatorLateral: 12 panels 0.6 cm

1.5 X0 CsI Calorimeter1.4*2*40 cm3 bars

X/Y plane, 121 mm pitchdistance between planes 1.6cm

W 0.07 X0

Super Agile Mask Super Agile Silicon plane

Tracker , 14 X/Y planes

Calorimeter

AntiCoincidence Top: 0.5cm plastic scintillatorLateral: 12 panels 0.6 cm

1.5 X0 CsI Calorimeter1.4*2*40 cm3 bars

X/Y plane, 121 µm pitchdistance between planes 1.6cm

W 0.07 X0

Super Agile Mask

Super Agile Silicon plane

Tracker , 14 X/Y planes

Cos-B 8/1975-4/1982

SAS-2 11/1972-7/1973

Energy Calorimeter

Spark ChamberTrigger Telescope

Cerenkov Counter

Anti-Coincidence Dome

AGILE2002-

EGRET4/19911999

AGILE Silicon Tracker prototype ladder

5 8x8 cm**2 CANBERRA silicon detectors with 195um strip pitch. The detectors aremechanical samples. The mechanical assembly and bonding hasbeen done by Mipot SPA. The procedure is as follows:-> the detectors are aligned one at a time and glued head on with non conductive expoxy gluewhich is made to polimerize with an infrared lamp for 20 minutes.

AGILE Silicon Tracker prototype

TA1Silicon wafer

AGILE Silicon Tracker beam test prototype

Three dimensional PSF as a function of photon energy for AGILE and EGRET.

GRB studies with AGILE

• Expected detection rate (above 50 MeV): 5-10 yr-1• Broad band spectral information: ~ 200 keV - 30 GeV• Rapid communication of GRB quicklook results

GRB 930131 • Study of the initial impulsive phase: Δt< 1 ms• Expected detection rate (above 50 MeV): 5-10 yr -1

More information on AGILE :

please visit us:

http://www.ifctr.mi.cnr.it/agile/ http://www.roma2.infn.it/infn/agile/

GLASTScheme

Gamma-RayLarge Area SpaceTelescope

Gamma-Ray Large Area Space Telescope

AnticoincidenceShield

Imaging calorimeter tower ( 8.5 Rad.Length)

Silicon Tracker tower18 planes of X Y silicon detectors + converters12 trays with 2.5% R.L. of Pb , 4 trays with 25% ,2 trays without converters

1.68 m

4*4 array of towers

GLAST Instrument Description

EGRET GLAST simulation

Geminga

IC 443

General Characteristics: imaging, wide field-of-view, pair-conversion telescope, backed by EMcalorimetry using modern HEP technology:

energy range: 10 MeV to 300 GeVenergy resolution: 10%effective area: > 8,000 cm2 (above 1 GeV)field-of-view: ~2π sr

point source sensitivity: 2 x 10-9 ph cm-2 s-1 (@ 100 MeV) 10-10 ph cm-2 s-1 ( > 1 GeV)

source location determination: 30 arcsec - 5 arcmincosmic ray/γ rejection > 105 to 1

EGRET(Spark Chamber) VS. GLAST(Silicon Strip Detector)

EGRET on Compton GRO(1991-2000)

GLAST Large Area Telescope(2006-2015)

Detector Technology: X-ray vs. Gamma-ray

X-ray (0.5 - 10keV)Focusing possible

Large effective areaExcellent energy resolutionVery low backgroundNarrow view

Gamma-ray(0.1-500GeV)No focusing possible

Wide field of viewLimited effective areaModerate energy resolutionHigh background

GLAST Large Area Telescope (LAT) DesignInstrument

Pair-conversion telescope

16 towers ⇒ modularity

height/width = 0.4 ⇒ large field-of-view

Tracker ModulesSi-strip detectors: fine pitch: 236 µm, high efficiency

12 front tracking planes (x,y): 0.45 Xo

reduce multiple scattering 4 back tracking planes (x,y): 1.0 Xo increase sensitivity > 1 GeV

One of 18Tracker trays(detectors top &

bottom)

GLAST Large Area Telescope (LAT) DesignInstrument

Pair-conversion telescope

Calorimeter Modules

Mechanical Prototype ofCarbon Cell Design

8.5 rl

Compression Cell Design

Hodoscopic Imaging Array of CsI crystals: ~ 8.5 rl depth PIN photodiode readout from both ends: 2 ch/xtal x 80 xtals/mod = 2,560 ch

segmentation allows pattern recognition (“imaging”) and leakage correction

GLAST Large Area Telescope (LAT) DesignInstrumentPair-conversion telescope

Anticoincidence ShieldSegmented, plastic scintillator tile array: high efficiency, low-noise, hermetic;

segment ACD sufficiently and only veto event if a track points to hit tile

ACD tile readoutwith Wavelength

Shifting Fiber

GLAST Performance

200 γ bursts per year

⇒ prompt emission sampled to > 20 µs

AGN flares > 2 mn

⇒ time profile + ΔE/E

⇒ physics of jets and acceleration

γ bursts delayed emission

GLAST LAT Strength-Large Field of View-

GLAST LAT Strength- Continuous All-sky Monitoring -

In scanning mode, the LAT will achieve after one daysensitivity sufficient to detect (5σ) the weakest EGRETsources

All 3EG sources + ~ 80 new in 2days

⇒ periodicity searches

(pulsars, X-ray binaries)

⇒ pulsar beam, emission vs.

luminosity, age, B

GLAST LAT Strength- New EGRET Catalog Every 2 days -

One year All-Sky Survey Simulation, Eγ > 100 MeV

All-sky intensity map based on five years EGRET data.

All-sky intensity map from a GLAST one year survey, based on the extrapolation of the number of sourcesversus sensitivity of EGRET

Active Galactic Nuclei (AGN) γ-ray emission:

Unanswered questions• What are the “primary particle in the γ-ray emitting beam?

• How are particles accelerated….. And where ?

• What is the highest energy the particles are accelerated to ?

( TeV- 107 - 108 TeV ?? )

• What causes AGN γ-ray flares?

Flux absorption due to the interaction with the infrared and microwave background

γ ray source

Microwave and infrared background

Ε=ω2

Ε=ω1

if the center of mass energy is:

photons interactions produce electron positron pairs

Flux absorption due to the interaction with the infrared and microwave background (2)

Ε=ω1

Ε=ω2

ϑ ω1 and ω1 are respectively the energies of the low and the high energies gamma ray and ϑ is their angle of incidence.

The cross section of the process γγ −> e+e- is:

where re is the classical radius of the electron and:

Flux absorption due to the interaction with the infrared and microwave background (3)

Ε=ω1

Ε=ω2

the ratio between the flux I(L) at a distance L from the sourceand the initial flux I can be written as:

I(L)/Io=exp(-kγ L)

where kγ is the absorption coefficient:

that contains the cross section and the low energy photon distribution.For the microwave spectrum:

10-2 100 102 104 106 108

Total Absorption ( microwave + infrared)

E(TeV)

Z=1 (high)

Z=0.03 (high)

Z=0.03 (low)

infrared only

Z=0.03 (high)

Ratio between surviving flux and initial flux versus photon energiesfor two different distances due to the sum of the infrared and black-body background

Transparency of the Universe

100 GeV

2.7 kOur galaxy

Super Cluster

γ γ e+ e-

p γ e+ e-

p γ π + π -Z~1 ~ 2 1028 cm

Z~0.03 ~2 1026 cm

1010 1012 1014 1016 1018 1020 1022 1024

10 TeV

(Mrk521)

Z~0.53, 2C279

Z~10-6 cm

Andromeda(700 kpc, 2.9Mly)LMC(50 kpc, 179kly)

Virgo Cluster 60mly, 18mpc

Flux absorption due to the interactionwith the infrared and microwave

background

an example on 3C279:• fixed background• different values of the Hubble constant

101 102 103

-2 s-1

E(GeV)

Fb=1.52 10-3 E-2.55

Ho=100 km s -1 Mpc -1

Ho=75 km s -1 Mpc -1

Ho=50 km s -1 Mpc -1

-2 s-1

GRB studies with GLAST

EGRET observed delayed GeV emission from the GRB of February 17, 1994, including a 20 GeV photon that arrived 80 minutes after the burst began. GLAST will make the definitive measurements of the high-energy behaviour of GRBs and GRB afterglows.

GRB studies with GLAST (2)

• Broad band spectral information: ~ 200 keV - 30 GeV• Rapid (few seconds) communication of GRB quicklook results• Single γ angular resolution ~10 arcmin at high energies for good source localization.

• Study of the initial impulsive phase: Δt< 1 ms• Expected detection rate (above 50 MeV): 50-100 yr -1

Gamma ray missions deadtimeGamma -ray mission deadtime

Test of Quantum Gravity(1q)

Candidate effect:

c2 P2 = E2 ( 1+ f(E/EQG ))E=photon energy EQG =effective quantum gravity energy scale

Deformed dispersion relation with function f model dependent function of E/EQG

if E<< EQG series expansion is applicablec2 P2 = E2 ( 1+ α(E/EQG )+ Ο(E/EQG ) 2)

v = δE/δP ~ c ( 1+ α(E/EQG ))vacuum as quantum-gravitational medium which respond differently to the propagation of particle

of different energies.(analogous to propagation through an electromagnetic plasma)Medium fluctuation at a scale of the order of Lp~10-33 cm

Δt = ~ α E/EQG D/c

Test of Quantum Gravity (2) Δt = ~ α E/EQG D/c

D ~ 2 1028 cm EQG ~1019 GeV c~3 1010 cm Δt(ms) ~ 60 ΔE(GeV)

Δti=0 Δtf=0t=ti

t=tfE1

even at pulsars distance: • D ~ 6 1021 cm Δt(µs) ~ 100 EQG ~1014 GeV

Cerenkov and Extensive air shower (EAS) gamma ray telescope concepts

Cerenkov

shower~8.5km

~ 40.000 m^2 , but no anticoincidence shield !

Optical detector

Particle detectors

Development of vertical 1-TeV proton and γ-ray showerProton γ-ray

Positions in the atmosphere of all showerelectrons above the Cerenkov threshold

Resulting Cerenkov images in the focal plane of a 10-m reflecting mirror .

Proton γ-ray

Whipple

Supernova remnants

MHK501

10 m telescopesE = >350 GeV

Location: Mt.Hopkinsin operation

“Solar Farm” Cerenkov gamma ray telescope concept

CELESTELocation: Thémis , France

STACEELocation: Albuquerque

~40 m2 mirror areaE =20 GeV - 200 GeV

Schedule: in test

Gamma-ray

heliostats

Secondary reflector

Camera boxWith PMT’s

Solartower

Hegra Telescope CT2car

220 m2 mirror areaE =10 GeV- 300 GeVLocation: La Palma(Canary Islands)Scheduled June 2004

7 Whipple like 10 mtelescopesE = 50 GeV -50TeVLocation: southern ArizonaScheduled 2005?

Whipple

Veritas

HESS Phase 2four 110m2 telescopesField of view 5 degDetection capabilityat E > 40 GeVSpectroscopy at E > 100 GeVLocation: NamibiaScheduled 2004

(artistic composition) (not yet real ! )

MILAGROArea 5000 m2

Field of view ~ 1 srE = 250 GeV - 50 TeVLocation: New Mexico2600m alt.Started June ‘99

ARGOArea 5.200 m2 (full coverage)(10.000 m2 with guard ring)Field of view ~ 1 srE = 50 GeV - 50 TeVLocation: Tibet 4300m alt.Scheduled 2002 (final conf.)

17400 Pads 56 by 60 cm2 each of ResistivePlate Chamber (RPC).Each pad subdivided in pick-up strips 6 cmwide for the space pattern inside the pad. The CLUSTER is made of 12 RPCs Pads

Test Carpetin Tibet

High voltage 8 kV

Resistive electrode plates Pick-up X strips

Pick-up Y stripsGRD

PVC Spacers

2 mm2 mm2 mm

The detector structure

Longitudinal development of the electron component of photon initiated shower( with electron threshold energy of 5 MeV and fluctuations superimposed )

16 X0 Yanbajiging

Number of electrons in the shower

Relation between altitude, number of Radiation Length and g/cm2 traversed

16 X0 Yanbajiging

Sky coverage of “all sky “ and Cerenkov telescopes in 2002

High galactic latitudes(Φb=2 10-5 γ cm-2 s-1 sr -1 (100 MeV/E)1.1). Cerenkov telescopes sensitivities(Veritas, MAGIC, Whipple, Hess, Celeste, Stacee, Hegra) are for 50 hours of observations.Large field ofview detectors sensitivities (AGILE, GLAST, Milagro, ARGO, AMS) are for 1 year of observation.

Sensitivity of γ-ray detectors

X and Gamma-ray detectors INFNgroundbased

INFN-ASISpace borne

Gamma-Ray Astronomy Long Term PlanUltimate Objective: To image the particle accelerator near the event

2005 2015 2025

Energy resolution

Angular resolution

Sensitivity

5 arc min

10 arc sec

0.03 arc sec

10-10 cm-2 s-1

10-12 cm-2 s-1

10-14 cm-2 s-1

creationaccelerationinjection

Underground, Under-ice, Underwater

Extensive Air ShowerDetectors

Direct detection

ParticleAstrophysicsExperiments

Modulation

furtheracceleration?

PropagationCosmic rays:about 10 Myears in the Galaxy(6-7 g/cm2)

Cosmic Rays

Atmosphere

Balloons ~ 40 km~3 g/cm2 residual atmosphere

Space experiments ~ 400 km

High MontainDetectors

Source

Cherencov Detectors

Particle Accelerators

il file PDF inhttp://people.roma2.infn.it/~aldo/

L'immagine seguente è stata usata per studiare i livelli di stress al CNR.Guarda i due delfini che saltano fuori dall'acqua.I due delfini sono identici.I ricercatori che hanno condotto lo studio sono giunti alla conclusione che una persona è ad un livello di stress troppoelevato se trova che i due delfini sono differenti. Il livello di stress è proporzionale alla quantità di differenze trovate,per cui più i due delfini sembrano differenti, più è elevato il livello di stress.Se vedete molte differenze tra i duedelfini, siete consigliati di smettere subito di studiare e fare immediatamente qualcosa di piacevole.

particle physics with space detectorspeople.roma2.infn.it/~morselli/astroparticelleroma1.pdf ·...

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