C. De Marzo, Dottorato in Fisica - 7 giugno 2005iaselli/Fisica dei rivelatori/rivel_astropart... ·...

C. De Marzo, Dottorato in Fisica - 7 giugno 2005

Apparati per Fisica Astroparticellare- i telescopi per neutrini di AE -C. N. De Marzo, Dip Fisica e INFN, Bari


Sommario

•preistoria dei telescopi per ν (NT)

• rivelatori a luce Čerenkov in acqua

•regole per un telescopio sott’acqua

•panorama internazionale dei telescopi

•cosa c’è e che cosa serbirebbe per un

buon NT


• dal 1930: lo studio dei raggi cosmici realizza un lunga tradizione di ricerche sotterranee e subacquee

• laboratori in Italia:- Monte dei Cappuccini (Torino)

- Monte Bianco (tunnel autostradale)- Lab. del Gran Sasso (da fine ‘80)


• fine anni ‘70: le teorie di Grande Unificazione prevedono il decadimento del protone (tprev ≈ 1031 y)

• alcuni laboratori sotterranei a ciò dedicati:- Soudan, Minnesota - IMB, Ohio- Kamioka, Giappone- NUSEX traforo del Monte Bianco- Frejus francese, nel traforo


• il decadimento del p non si vede !

• si vedono tanti µ della rad. cosmicaed anche neutrini atmosferici

(cioè µ provenienti dal basso)


distribuzione dei muoni nel lab. del Frejus in funzione dell’angolo (l’ordinata moltipl. x cosθ)

in ascissa la ‘slanth depth’

∝ cos(θ)


atmosphericMuons

AtmosphericNeutrinos

dΦ/dΩ cm-2 s-1 sr-1

cosθν

10-9

10-11

10-13

10-15

10-17

2400 m depthE > 1 TeV

Spettro dei µ in un laboratoriosotterraneo

(simulato)


reazioni base di produzione dei neutrini atmosferici

p + N p + N + π+ + π- + π° + . . .

π± µ± + νµ

µ± e± + νµ + νe

τπ = 2.6 10-8 s τµ = 2.2 10-6 s


meccanismo detto “beam dump”


tipi di sorgenti• Galattiche (SNR, micro-quasar, centro galattico)

• Extra-galattiche (AGN, fondo µ-onde,. . ., GRB)

• Esotiche (difetti topologici, . . .)


Throughgoing

Internal Down

Internal Up

µ stop

Throughgoing: Emedian∼50 GeV 180/yrInternal Up: Emedian∼3.5 GeV 50/yrInternal Down+Stopping µ:Emedian∼4.2 GeV 35+35/yr (expected)


distribuzione del tempo di volo dei muoni in MACRO


psf di MACRO∆θ = 0.6°(dall’analisi

di 106 coppie di muoni)


l’ombra della Luna in MACRO

(PRD59 (1999)).


Mappa dei 1356 νµ di MACRO

previsioni di vari modelli del flusso diffusoLearned Mannheim

AGNGZK

pγ AGN corespp AGN cores

pγ blazar

GRB

WB Limit

Stecker

Nellen

Mannheim

Bierman

Waxman


Macro: ≈ 103 m2

≈ 104 m3

per fare astronomia dei neutrini almeno 1 km3 = 109 m3

un volume 5 ordini di grandezza maggiore


Conteggi da flusso diffuso in 1 km3

Guaranteed (GZK): 0.5/year Diffuse GRB: Waxman 50/yearDiffuse AGN (thin): Mannheim few/year

(thick): >100/year


In conclusione:- occorrono rivelatori con Aeff. ≈ km2

e volumi ≈ km3 impossibili con tecniche ‘a la MACRO’

- difficoltà tecniche a scavare sale sotteranee ed elevato costo del rivelatore


Per ciò l’unica soluzione praticabile sono gli apparati basati sulla rivelazione di

luce Čerenkov ed immersi in acqua a grande profondità


Detecting neutrinos

ν

µ

γč

43°In ANTARES2400 m depth

Cherenkov light from µ induced by ν interaction detected by 3D PMT arrayTime & position of hits allow the reconstruction of the µ (~ ν) trajectoryinteraction

νµ µ

N X

W

Both σνN & µ range ∝ Eν


la catena di cause ed effetti è:

ν + leptone hνČerenkov

in definitiva si misurano ampiezze e tempi dei segnali ai Moduli Ottici (OM)

codice di ricostruzione delle tracce


Ricostruzione:- traccia (6 param.) = in base alle

misure di tempo di arrivo dei fotoni e posizione dei relativi OM

- energia = in base alla luce totale raccolta


risoluzione angolare in ANTARES

Reconstruction resolution limited by light diffusion in water and phototube TTs


Requested Physics Performancefor a Neutrino Telescope - I

• Critical issues:• effective area

(determines muon rate)• angular resolution

(for point source searches)• energy resolution

(diffuse flux searches)• background rejection

(rejects mis-reconstructed cosmic muons)


NT Requested Performance - II

- High depth- for background reduction (cosmic ray muons, bioluminescence, . . .)

- Good environmental parameters- high water trasparency

- reduced bio-luminescence

- reduced sedimentation and bio-fouling- low sea-water current


proprietà del mezzo:lung. di assorbimento: La = 1/a (trasp.)

lung. di scattering: Lb = 1/b (scatt.)

lungh. di attenuazione: c = a + b

fondi: potassio (40K)

bio-luminescenza


Confronto: liquido vs ghiaccio

λa = 40÷70 m λa = 200 mλsc ≈ 75 m λa = 25 m

40K ~ 40 kHz (mare) = 0bio-lumin. variabile assente app. riconfigurabile non riconfig.


Telescopi per neutrini nel mondo

• BAIKAL, lago in Siberia prototipo (192 OM)

• AMANDA, Polo Sud presa dati

• ANTARES, Marsiglia in costruzione

• NEMO, Capo Passero (Sicilia) progetto, test di

prototipi

• NESTOR, Pylos (GR) prototipo (12 OM)


Lago Bajkal

Bajkal


The first running detector: Baikal192 OM arranged in 8 strings, 72 m heighteffective area >2000 m2 (Eµ>1 TeV)

3600 m

1366

m

• Successfully running since 10 years• Atmospheric neutrino flux measured• Further upgrades planned, but km3 hardly reachable


NESTOR a Pylos, Peloponneso

NESTORNEMO


NESTOR• Tower based detector• Up- and downward looking PMTs• 3800 m deep• Dry connections• First floor (reduced size) with

12 PMTs deployed and operated in 2003


The ANTARES Collab.

University of SheffieldUniversity of Leeds

CPPM, Marseille DSM/DAPNIA/CEA, SaclayC.O.M. MarseilleIFREMER, Toulon/BrestLAM, MarseilleIReS, StrasbourgUniv. de H.-A., MulhouseObservatoire de la Côte

d’Azur

INFN andUniversity of Bari University of Bologna University of Catania University of GenovaLNS – CataniaUniversity of PisaUniversity of Rome

IFIC, Valencia

NIKHEF,Amsterdam

ITEP, Moscou

Universitat, Erlangen

Particle physicists, oceanographers, astronomers

180 physicists, engineers and sea scientists from 24 European institutes:


ANTARES Site

Submarine Cable -2475m

La Seyne sur Mer

Institut Michel Pacha

Shore Station

C. De Marzo, Dottorato in Fisica - 7 giugno 2005Glass sphere (Nautillus)

Photomultiplier: 10 inch Hamamatsu

Mu metal magnetic shield Active PMT base (ISEG)

The Optical Module

LED pulser


Profiler for Sea currant

(ADCP)

Probe for salinity and temperature (CTD)

Probe for Sound velocity

Junction Box

LED Beacon

Laser Beacon

Seismograph

hydrophones hydrophone

5 Storeys of Optical Modules

Anchor with electronics containers Link Cables

Prototype Linesoperated in 2003Prototype

SectorLine (PSL)

Dec 2002

MiniInstrumentation

Line (MIL)

Feb 2003

Dec2002

March2003

C. De Marzo, Dottorato in Fisica - 7 giugno 2005© F. Montanet

• 12 lines• 25 storeys / line• 3 PMTs / storey• 900 PMTs

~70 m

100 m

350 m14.5 m

Submarine links

JunctionBox

40 km toshore

Anchor/line socket

to be deployed by 2005-2007

a storey

2500m depth


100m

100m

LASER Beacon

LED beacon

MILPSL

10m

100m

Calibrations with laser and LED


Acoustic Positioning

~ 1 cmInter-transponder≤ 6 cm Rang.Transpond.

< 6 mm Inter-rangemeter

precision (σ)Devices

Triangulation → ~5 cm final precision

10 cm

10 cm

Hydrophone positionmeasured every 10 secvariation < 1 cm within 10 s

Displacement < 70 cmduring one night

Energy & angular resolution

Energy resolutionlg(Erec/EMC)

Factor 3

Factor 2

Resolution dominated byreconstructonLimiting value ~0.15°

ν

µ

Resolution dominated by kinematicangle θνµ

Reconstruction resolutionlimited by phototube TTSand light diffusion in water


Calibrazione angolare

- µ dall’alto

- ombra della Luna

- ombra della costa


Cable deployment Oct. 2001


il Nautile


Il ROV VICTOR

il ROV VICTOR


2000-2003 AMANDA sky plot: 3369 events

sigma

No evidence for point-like sources with an Eν-2 energy

spectrum based on the first four years of AMANDA-II. The strongest excess was observed from the direction of the Crab nebula, with 10 events where 5 are expected.


Observation time for up-going neutrino events

TeV sourcesµQSO

Galactic centre

Galactic coordinatesMediterranean km3

ICECUBE

1.5 π sr common view per day


Perciò occorrono due telescopi per esplorare tutto il Cielo

• Torniamo nel Mediterraneo:• ANTARES: 0.1 km2, 0.03 km3 (Marsiglia)

• NEMO: 1.5 km2, 1 km3 (Sicilia)


the NEMO CollaborationINFNBari, Bologna, Catania, Genova, LNF, LNS, Napoli, Pisa, RomaUniversitàBari, Bologna, Catania, Genova, Napoli, Pisa, Roma “La Sapienza”

CNRIstituto di Oceanografia Fisica, La SpeziaIstituto di Biologia del Mare, VeneziaIstituto Sperimentale Talassografico, Messina

Istituto Nazionale di Geofisica e Vulcanologia (INGV)

Istituto Nazionale di Oceanografia e Geofisica Sperimentale (OGS)

Istituto Superiore delle Comunicazioni e delle Tecnologie dell’Informazione (ISCTI)

More than 60 researchers from INFN and other italian institutes


Nemo site exploration activities

• Since 1998 continuous monitoring of a deep sea site located in a wide abyssal plain close (≈80 km) to the coast of Sicily (Capo Passero) at about 3500 m

• More than 20 sea campaigns on the site to measure:– water optical properties– optical background– deep sea currents– nature and quantity of sedimenting material


Comparison of NEMO and Antares dataon water optical properties

• Absorption lengths measured in Capo Passero are compatible with optically pure sea water data

• Large differences between Toulon and Capo Passero are observed in the blue region

• Values measured with the Antares Test 3’ setup are in good agreement with the AC9 data

Optical water properties have been mesured in the summer 2002 in Capo Passero and Toulon in two joint NEMO-ANTARES campaigns


Optical backgroundLight produced by biological entities(bioluminescence) → random bursts with very high counting rateDecay of radioactive elements (mainly40K) → stable frequency noise (≈30 kHzon a 8” PMT at 0.3 p.e. threshold)

No luminescent bacteria have been observedin Capo Passero below 2500 m

Data taken by Istituto Sperimentale Talassografico, CNR, Messina


Optical background at Capo PasseroMeasurements

performed with the device developed by

ANTARES

Dead time:Fraction of time with

Rate > 200 kHz

PMT: 10”

Thres: ~.5 SPE


the NEMO towerHeight:compacted 15:20 mtotal 750 minstrumented 600 mn. beams 16 to 20n. PMT 64 to 80

The NEMO tower is a semi-rigid 3D structure designed to allow easy deployment and recovery. High local PMT density is designed to perform local trigger.

The NEMO tower is a semi-rigid 3D structure designed to allow easy deployment and recovery. High local PMT density is designed to perform local trigger.

Beams:length 20mspacing 40 m

A 1:5 scale model of the tower (4 floors)tested in shallow water on April 2004

floor

Tower compacted

Tower unfolded


electro optical cable from shore

140÷300m

secondary JBs

primary JB

towers

• 1 main Junction Box

• 8 ÷ 10 secondary Junction Boxes

• 60 ÷ 80 towers

• 140 ÷ 300 m between each tower• 16 ÷ 18 floors for each tower • 64 ÷ 72 PMT for each tower

• 4000 ÷ 6000 PMTs

• 1 main Junction Box

• 8 ÷ 10 secondary Junction Boxes

• 60 ÷ 80 towers

• 140 ÷ 300 m between each tower• 16 ÷ 18 floors for each tower • 64 ÷ 72 PMT for each tower

• 4000 ÷ 6000 PMTs

NEMO will be modular detectorGreat advantage in terms of reconfigurability

Main JB

1st Secondary JB……

Nst Secondary JB 8 ÷10 towers

8 ÷10 towers

Data transmission system: Mostly passive component, Low power consumptionBased on DWDM technique

First Multiplation Stage at tower base.

Second multiplation stage at secondary JB.

Signals from primary JB go directly to shore

Data transmission system: Mostly passive component, Low power consumptionBased on DWDM technique

First Multiplation Stage at tower base.

Second multiplation stage at secondary JB.

Signals from primary JB go directly to shore


Cable features:Cable features:

10 Optics Fiber standard ITU- T G-652

6 Electrical Conductors Φ 4 mm2

2.330 mDouble Armed Cable

20.595 m Single Armed Cable

Drop cable 2Drop cable 25.220 m5.220 m

Drop cable 1Drop cable 15.000 m5.000 m

joint

BU

joint

joint

GEOSTAR

NEMO Phase 1 Lab

Layout of the installation

LNS test site in Catania


a multidisciplinary laboratory

Sperm whale clicks (echo localization)GEOSTAR SN-1 deep sea station

First data from 2000 m• GEOSTAR SN-1, a deep sea station for on-line seismic and environmental monitoring by INGV. The NEMO test site is the Italian site for ESONET (European Seafloor Observatory NETwork);• OνDE, for on-line deep sea acoustic background monitoring.


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C. De Marzo, Dottorato in Fisica - 7 giugno 2005iaselli/Fisica dei rivelatori/rivel_astropart... ·...

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