Download PPT - IN2P3

Instrumentation for
Astroparticle Physics
W. Hofmann
MPI für Kernphysik
Heidelberg

Neutrinos
(MeV: sun, SN
GeV: atmosphere
PeV: CR accerators)
Dark
matter

Monopoles
Axions
Cosmic ray
particles -> 1020 eV
Electromagnetic
radiation -> 100 TeV

Grav.
waves

State of the field: a charming infant
Optical
100000000
1000000
Astrophysics
with gamma rays
and neutrinos
Radio
X-Ray
IR
10000
UV
Gamma
100
100000
R osat
G L AS T
G ing a
Eins tein
1000
Gamm a (GeV)
CG R O
100
U huru
C O S -B
Gam m a (TeV)
Energy [eV]
1
X-Ray (keV)
10000
Num ber of sources
Peak detected flux
Detection threshold
10
C h ere nkov
te le sco pes
S A S-2
10-6
100
106
1012
1
1960
Neutrinos (?)
Flux
sensitivity
1970
1980
1990
Year
Angular resolution [degr.]
Neutrinos
100
Gamma
10-2
10-4
Angular
resolution
10-6
Optical
X-Ray
Radio
10-6
Energy [eV]
100
106
1012
2000
2010
Number
of sources
Gamma rays and cosmic rays
Cosmic ray
particles -> 1020 eV
Electromagnetic
radiation -> 100 TeV

The big issues in cosmic-ray physics
eV
• at low (GeV – TeV) energy:
antiparticles in cosmic rays?
AMS
• at medium (PeV) energy
elemental composition, change in
composition at knee?
(KASKADE,…)
• at high (EeV) energy
spectrum, particles beyond
GKZ cutoff?
AUGER
• Sources of cosmic rays
traced in the light of
(secondary) gamma rays
g-yield = CR density x target density
EGRET
~ 100 MeV
In the Earth’s
atmosphere
Radio
Infrared
Ultraviolet
Visible
X-Ray
Gamma ray
Propagation of electromagnetic radiation
In space
500 km
10
100 km
Sea
level
Air shower
Fluorescence light
Radio waves
Cherenkov light
Particles at ground level
Range [kpc]
10 km
10
10
10
10
10
10
10
10
8
7
6
5
Horizon
due to gg
interactions
M kn 501
4
3
2
1
Nearest galaxy
Size of Milky W ay
0
10
10
10
11
10
12
10
13
10
14
E [eV]
similar effect:
Cosmic-ray propagation
cuts off at 1020 eV
10
15
10
16
10
17
GeV/TeV CR: Alpha Magnetic Spectrometer
AMS-01 (1998)
AMS-02 on ISS
GLAST: g-rays in the GeV energy range
VHE air shower detectors: Cherenkov telescopes
Effective
detection area:
~ 50000 m2
~ 120 m
~ 1o
100 photons/m2 TeV
within a few ns
~ 120 m
Image of the shower
in the PMT camera
Image
Orientation
 shower direction
Intensity
 energy of primary
Shape
 type of primary
Telling g-rays from hadronic cosmic rays
z
z
g
x
y
y
x
p
g (?)
x
x
p (?)
The imaging atmospheric Cherenkov technique
Pioneered by the
WHIPPLE group
Perfectioned in
CAT telescope
Stereoscopy
with HEGRA
WHIPPLE
490 PMT
camera
Four eyes see better than one: H.E.S.S.
(and VERITAS, CANGAROO, …)
12 m Cherenkov telescopes
under construction in Namibia
Combine
Stereoscopy from HEGRA telescopes
• improved angular resolution
• enhanced background suppression
Trigger and fine pixels from CAT telescopes
Monitoring from Durham telescopes
•
•
•
•
•
•
100 m2 mirror
15 m focal length
960 PMT camera
1 GHz analog pipeline
50 GeV threshold
10 times improved
sensitivity cf. HEGRA
Source hunting with MAGIC
•
•
•
•
•
17 m dish, 220 m2 active mirror
low weight  fast positioning
high-speed optics and electronics
initial PMT camera
later GaAsP and APD detectors
 10 GeV threshold
Aluminum mirrors
PMT with hemispherical window
and optical signal transmission
Sensitivity and limitations of the technique
Angular resolution,
cosmic-ray rejection limited by
• Shower fluctuations
• Earth magnetic field
Also, light yield depends on height!
Side view of
shower
Hard to go beyond mCrab
sensitivities with the
imaging Cherenkov technique …
Angular resolution
for “ideal” detector
Irreducible background
• Cosmic-ray electrons
can only be discriminated on the
basis of shower direction.
Better vision – novel photon detectors
2500
C ost of dish
e ~ 62%
Cost [Euro]
2000
e ~ 22%
1500
1000
500
0
e ~ 15%
Cost of
cam era
0
5
10
15
20
25
D ish diam eter [m]
Better photon detectors
for Cherenkov telescopes
• allow large savings
• improve performance
need m2 cathode area …
• Hybrid PMTs
• GaAsP limited to few 100 mm2
• Si (APD) even smaller, QE below CCD
An alternative approach: non-imaging detectors
STACEE
CELESTE secondary
reflector and PMTs
Large mirror area and hence
low energy threshold
Poor cosmic-ray rejection
Significant learning curve
CELESTE sees Crab at 50 GeV
Competitive in the long run?
Tail catchers: particle detectors
Tibet air
shower array
(Scintillators)
Milagro, Los Alamos
(Water Cherenkov)
High altitude and
large area coverage
Avantages
• large solid angle
• 100% duty cyle
Disadvantages
• TeV+ threshold
• marginal (Crab-level) sensitivity
Complementary to Cherenkov telescopes
ARGO,Tibet
(RPC array)
planned
The ultimate experience: AUGER
Air shower detector
• 3000 km2 area
• two detector technologies
particle detectors
fluorescence telescopes
• ~ 20000 events > 1019 eV
• ~ 100 events > 1020 eV
1600 detectors
1.5 km spacing
AUGER fluorescence detectors
AUGER performance
Detection area
Simulated spectrum
The view from above: OWL
CR
n
106 pixel focal plane
flat panel PMTs ?
> 50o field of view
Threshold: 1019-1020 eV
Eff. area: few 106 km2sr
Neutrinos
(MeV: sun, SN
GeV: atmosphere
PeV: CR accerators)

High-Energy Neutrino Astrophysics
Proton accelerators
generate roughly equal numbers
of gamma rays and neutrinos !
• Neutrinos are not absorbed in
sources; they escape even from
strong sources
• Neutrinos do not interact
during propagation
Background:
atmospheric neutrinos
Signal from cosmic
accelerators
Scientific American
Extreme Engineering Issue
Seven wonders of modern astronomy
•
•
•
•
•
•
•
4 strings
The sharpest
The biggest
The farthest flung
The most extensive
The swiftest
The deadliest
The weirdest:
AMANDA at the south pole
10 strings
AMANDA II (2000)
19 strings, eff. area ~ 5x104 m2
Detection: Cherenkov light in water / ice
ICE CUBE,
ANTARES:
1000000000 m3
~ 5000 PMTs
Threshold ~ 1 TeV
Key difference:
1 km deep under water / ice
m
Ice / AMANDA II:
~ 100 m absorption length,
~ 20 m scattering length
 diffusive component
 angular resolution 1.2o
Water / ANTARES, NESTOR
~ 60 m absorption length,
~ 200 m scattering length
 angular resolution 0.2o
n
Instrument R&D
•
•
•
•
•
ANTARES
Demonstrator
Optical module design
Deployment schemes
PMTs
Signal transmission
Digital modules
Module with
optical signal
transmission
(AMANDA)
ARS 1 GHz analog
ring sampler ASIC
with digital signal
procession
(ANTARES)
AMANDA at the South Pole
n-Sky (AMANDA ’97)
ICECUBE
80 “Strings” of 60 PMTs
in 1400 – 2300 m depth
Physics issues (ICECUBE,
-
ANTARES, NESTOR):
neutrinos from CR accelerators
neutrinos from DM annihilation
atmospheric neutrinos, oscillations
magnetic monopoles
galactic supernovae
-…
Solar neutrinos
n
Super-Kamiokande:
the neutrino image of the sun
Detectors for solar (MeV) neutrinos
SuperKamiokande
Water Cherenkov
SNO: HeavyWater Cherenkov
BOREXINO,
LENS:
KAMLAND(2):
Liquid Scintillator
Liquid Scintillator with “Tag”
pp
n
Be
pep
n
e
n
e
n-flavor
no (NC)
n-energy res. poor
threshold
4-5 MeV
ne
e
D
pp
yes (CC)
good
4-5 MeV
n
e
n
e
no (NC)
poor
1 MeV
ne
e
Yb
Lu*
g
50 ns
yes (CC)
good
0.3 MeV
Alternative techniques
ICARUS: liquid argon DC
air
shower
HELLAZ: TPC
delta-ray
HERON: superfluid He;
evaporation by photons/rotons
and scintillation
Dark
matter

The dark side of the universe
CMB (Boomerang, Maxima)
High-z Supernovae, BBN
 ~ 1.0
M ~ 0.2-0.3
B ~ 0.03 – 0.05
 most matter is dark,
nonbaryonic
Particle physics candidates, e.g.
WIMPs, accumulate in the halo of
galaxies (local density 0.3 GeV/cm3)
Searching for WIMPs
Principle: elastic scattering on nuclei
mW M
2

m
v
(1  cos )
ER
W
2
(mW  M )
Typ. recoil: a few 100 eV / GeV WIMP mass
Typ. rate: a few events / kg / day
WIMP Signature:
7% annual modulation
Peak velocity
June 2nd
Light Recoil
Phonons
WIMP
Earth
v  30 km/s
Sun
Ionization
Cu
Pb
Dark matter halo
<v>  300 km/s
v  230 km/s
Galactic
centre
The classical approach: DAMA
9 NaI dectors, total ~100 kg
Threshold ca. 1-2 keV (equiv. Energy)
Background ca. 1.5-2 /kg keV Day
Similar:
UKDMC,
…
Deviation from average rate, 2 – 6 keV
+3%
0
-3%
Significance of modulation: 4 s
near threshold rate saturated by dark matter!
Mind over matter: cryogenic detectors
Ionisation
Phonons
CDMS (Si, Ge)
Thermometer: superconducting
film near transition (20 mk);
Ionisation
(and Edelweiss, …)
Light
Phononen
Phonons
CRESST (CaWO4)
Thermometer: superconducting
film (15 mK)
Detection of light using absorber
with thermometer
Reach of cryogenic detectors
Romani et al.
Spectroscopy of
single photons
from the Crab
pulsar
Transition edge
sensor coupled to
W detector
(18m x 18m x 40 nm)
DE < 0.15 eV
Challenges:
Size
Resolution
Speed (usually limited to kHz)
CDMS vs. DAMA … and the future
R. Gaitskill, V. Mandic
http://cdms.berkeley.edu/limitplots/
Heidelberg-Moskau
DAMA (3 s)
CDMS
DAMA
58000 kg-days
3800 m water equiv.
CDMS:
11 kg-days
16 m water equiv.
CDMS Stanford
CDMS Soudan
CRESST
CDMS Soudan
GENIUS
GENIUS
GENIUS: the simpler the better ?
Germanium detectors (100 kg)
supended in ultra-pure liquid nitrogen
~ 12 m
Test facility under construction
at LNGS
Bubble chamber revival: Picasso
Rate
dE/dx
threshold
adjusted
by detector
temperature
20o C
15o C
10o C
The Picasso
detectors:
superheated droplets
in a polymerized gel.
Detection via noise
(piezo transducer)
En
First results –
not yet competitive,
but in the right
ballpark
Astroparticle Physics
- a fascinating application of
particle physics instrumentation
to new questions
- numerous interesting and
challenging developments, both
in physics and instrumentation
- impossible to do
the field justice
in 45 min. !