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Detector and detector systems for particle and nuclear physics I
E-mail: [email protected]
Detector 1
Friday 9.1.2015
PARTICLE DETECTION
2
Particle cannot be seen or measured „directly“
Only the result of an interaction with matterwill be observed.
In the end, everything is converted to optical pictures electric signals
Particle Detection Principle
The detection of particles happens via theirenergy loss in the material it traverses ...
Charged particles Ionization, Bremsstrahlung, Cherenkov ...
Hadrons Nuclear interactions
Photons Photo, Compton effect, pair production
Neutrinos Weak interactions
3
Measurement of Particle Properties
• Charge– direction
• Momentum B, radius
• Lifetime– measurement of path length
• Velocity time of flight (TOF)
LB
NL I
mage L
ibra
ry
Discovery of the Positron1932 Carl Anderson,
Noble Prize 1936
4
pvmRBq
DETECTOR TYPES
Scintillation detectors
Semiconductor detectors
Gaseous detectors
Calorimeter
ECAL: Electromagnetic calorimeter
HCAL: Hadronic calorimeter
Tracking detectors
(tracks momentum, charge, decay)
Multipurpose detectors / high precision experiments
combination of different detectors
(FAIR PANDA)5
Detector 6
coverage of full solid angle (no cracks, fine segmentation)
measurement of momentum and/or energy
detect, track and identify all particles (mass, charge)
fast response, no dead time
practical limitations (technology, space, budget) !
end products
charged particles
neutral particles
photons
The ‘ideal’ particle detector should provide…
Detector 7
• number of particles
• event topology
• momentum / energy
• particle identity
cannot be achieved
with a single detector
detector
system
Detector systems
GEOMETRY
Magnet concepts
Imagnet
B
coil
Imagnet
B
µ
µ
Solenoid (air-core) Toroid
CMS, KLOE, FOPI, PANDA ATLAS
+ strong and homogeneous field
- massive iron return yoke
- limited in size (cost)
- solenoid thickness (radiation length)
+ large air core, no iron, less material
- additional solenoid in the inner parts
-- inhomogeneous field
- complex structure
8
ATLAS and CMS magnet coils
ATLAS toroid coils
Autumn 2005
CMS solenoid(5 segments)
9
CMS: SC, 4.0T, Ø5.9m, L 12.5mAtlas: D=9m; L=24m
Exploded View of CMS
MUON BARREL
CALORIMETERSECAL
PbWO4
crystals
Cathode Strip Chambers
Resistive Plate Chambers Drift Tube
Chambers Resistive Plate
Chambers
SUPERCONDUCTING
COIL
IRON YOKE
TRACKER
Silicon micro-strips
pixles
MUON
ENDCAPS
Total weight : 12,500 t
Overall diameter : 15 m
Overall length : 21.6 m
Magnetic field : 4 Tesla
HCAL
Plastic scintillator/brass
sandwich
10
Slice through the CMS detectorParticle interaction and reconstruction
different detectors for different particles
11
12
CMS
Detectors interleaved with the magnet yoke steel layers
13Detector
Collider versus fixed target
14Detector
Detector parameters
• solid angle
• granularity
• dead time / rate capability
• resolution
• efficiency
• material budget
• radiation tolerance
• COST !!
Example for a collider and a fixed target experiment
KLOE at DANE
PANDA at FAIR
15Detector
16
DANE
e+-e-
collider
Accu.
Hadron 2013
K+
K-
e
e ee
ee
e
e
e
e
e+
e+
e+
e+
e+
e+e+
e+
DANE principle
• operates at the centre-of-mass energy of the mesonmass m = 1019.413 ± .008 MeVwidth = 4.43 ± .06 MeV
• produced via e+e- collision with(e+e- → ) ~ 5 µb
production rate 2.5 x 103 s-1
monochromatic kaon beam (127 MeV/c) bremsstrahlung loss per turn ~ 14 keV
17
About strange particles…
The quark eigenstates are:
The CP eigenstates are:2
KKK ,
2
KKK
00
2
00
1
+
00 K ,K
M. Gell-Mann A. Pais
19Detector
The KLOE Detector
20Detector
The KLOE Detector
Electromagnetic
calorimeter
Interaction
region
Drift
chamber
Iron
yoke
Superconducting
coils
21Detector
22Detector
KLOE calorimeter
KLOE calorimeter
density ~ 5.0 g/cm3
total length of fibres ~ 15000 kmread out by ~ 5000 mesh PM SiPMs
Photon energy resolution (E)/E = 5.7%xE(GeV)-1/2
time resolution t/t = 54 [ps]xE(GeV)-1/2
+
+
0
000
sK
Determination of the neutral kaon mass, by measuring 4 gammas
Neutron detection efficiency
Threshold at 1 MeV
Threshold at 3 MeV
MC simulation, confirmed with measurements at TSL (Uppsala)
PANDA Detector @ FAIR
27Detector
Anti-Proton
ANnihilation at
DArmstadt
Facility for Antiproton and Ion Research
28Detector
Particle physics
Hadron physics
Nuclear physics
Study the strong interaction with antiprotons
Questions ...
Mechanism of confinement ?
Inner structure of hadrons ?
Origin of mass and spin (macroscopic properties) ?
Exotic colour neutral objects?
Physics goals of PANDA
29Detector
Hadron SpectroscopyExperimental Goals: mass, width & quantum numbers of
resonances
Charm Hadrons: charmonia, D-mesons, charm baryons
to understand new XYZ states, Ds(2317) and others
Exotic QCD States: glueballs, hybrids, multi-quarks
Spectroscopy with Antiprotons:
Production of states of all quantum numbers
Resonance scanning with high resolution
Physics goals of PANDA
30Detector
31
Nuclear Physics
Charm in the MediumMesons in nuclear matterMasses change in nuclei
D-mass lowerLower D D threshold
J/ψ absorption in nuclei
Hypernuclei3rd dimension in nuclear chartDouble hypernucleiproduction via Ξ- capture Λ Λ interaction in nucleus
Other topicsShort range correlationsColor transparency
Physics goals of PANDA
Detector
Detector 32
33Detector
Physics goals of PANDA
Hadron StructureGeneralized Parton Distributions
➔ Formfactors and structure functions
Timelike Nucleon Formfactors
Drell-Yan Process
full PWA or polarized beam/target
PANDA Physics Report www-panda.gsi.de
34Detector
35Detector
PANDA - detection concept
Detector 36
Stochastic cooling
Stochastic cooling
Injection
Electroncooler
High Energy Storage Ring
Up to 1011 stored antiprotons
Beam momentum: (1.5 ... 15) GeV/c
Phase-space cooling
Fixed internal target
Operation modes
a) High luminosity: L = 2 · 1032 cm-2 s-1 p/p 10-4
b) High resolution: L = 1031 cm-2 s-1 p/p 4 · 10-5
PANDA @ HESR
Detector 37
TARGET SPECTROMETER FORWARD SPECTROMETER
DipoleMuon ID
RICHVertex
Central TrackerElectromag.
Calorimeters
Muon
Range System
Drift ChambersSolenoid
Target
DIRC
The PANDA Spectrometer
38
Superconducting magnet Central field: |B| = Bz = 2 T
High field homogeneity: 2%
Dimensions inner bore: 1.9 m / length: 2.7 m
Coil and cryostate
zbeam axis
Target pipewarm hole
Outer yoke dimension: 2.3 m / length: 4.9 m
Total weight: ~ 300 t
Iron flux
return yoke
Laminated layers for
muon range system
PANDA - Solenoid
39
Superconducting magnet
Field integral (bending power): 2 Tm
Deflection of antiprotons with p =15 GeV/c: 2.2°
Bending variation: 15%
Vertical acceptance: 5°
Horizontal acceptance: 10°
Total weight: 200 t
Forward tracking detectors partly integrated
PANDA – Dipole magnet
40
Beam pipe
Target pipe
Target dumping
system
Target production
Vacuum pumps(VP)
(VP)
(VP)
(VP)
~ 2
m
Injectionpoint
• Primary target setup
Appropriate cut-outs
in solenoid magnet
Beam-target cross
Design compatible
with all different options
PANDA – Target system
The new INFN-SMI-GSI cluster jet
Cluster-jet nozzle at GSI
max = 1,4·1015 atoms/cm2
(29,7 K and 15 bar)
43
Forward
spectrometerTarget spectrometer
Micro-Vertex
Detector
Central tracking (Helix fit)
Forward tracking(Straight lines)
Straw-tube
layers
Outer
tracker
GEM
stations
PANDA – Tracking
44PhiPsi2011 BINP, Novosibirsk
Design of the MVD
4 barrels and 6 disks
Continuous readout
Inner layers: hybrid pixels
(100x100 µm2)
Outer layers:
double sided strips:
Rectangles & trapezoids
NXYTER readout
Mixed forward disks
(pixel/strips)
Challenges
Low mass supports
Cooling in a small volume
Radiation tolerance
PANDA – Micro Vertex Detector
45
Central Tracker σrφ~150µm , σz~1mm
δp/p~1% (with MVD)
Material budget ~1% X0
Straw Tube Tracker
27 µm thin mylar tubes, 1 cm Ø
Stability due to 1 bar overpressure
GEM Time Projection Chamber
Continuous sampling
GEMs to reduce ion feedback
Online track finding
Forward GEM Tracker Large area GEM foils Ultra thin coating
PANDA – Central tracker
46
Detector Layout 4500 straws in 20-26 layers
Tube made of 27 µm thin
Al-mylar, Ø=1cm
Rin= 150 mm, Rout= 420 mm
l=1500 mm
Self-supporting straw double
layers at ~1 bar overp.(Ar/CO2)
Material BudgetMax. 26 layers,
0.05 % X/X0 per layer
Total 1.3% X/X0
Detector performance r/ resolution: 130 µm
z resolution: ~ 1 mm
Prototype test at COSY-TOF
PANDA – Straw tubes
47Detector
The PANDA Detector - GEM-TPC
48
PANDA PID Requirements:
Particle identification essential
Momentum range 200 MeV/c – 10 GeV/c
Different processes for PID needed
PID Processes:
Cherenkov radiation: above 1 GeV
Radiators: quartz, aerogel, C4F10
Energy loss: below 1 GeV
Best accuracy with TPC
Time of flight
Problem: no start detector
Electromagnetic showers:
EMC for e and γ
PANDA – Particle IDentification
49PhiPsi2011 BINP, Novosibirsk
Forward spectrometerTarget spectrometer
Barrel DIRC RICH
D etection of I nternally R eflected C herenkov
light
Radiator material: Fused silica 3 /K separation
0.8 GeV/c p 5 GeV/c
Radiator materials: Aerogel / C14F10
/K separation2 GeV/c p 15 GeV/c
R ingI magingCH erenkov
detector
Disc DIRC
PANDA – Cherenkov detectors
50
Forward spectrometerTarget spectrometer
Barrel EMC Shashlyk
calorimeter
Endcap
structures
Operated at -25°C
Cristal: PbWO4
~ 15,000 cristals
Lead-scintillator sandwiches351 modules
(13 rows / 27 columns)
PANDA – Calorimeter
51PhiPsi2011 BINP, Novosibirsk
Barrel Calorimeter
11000 PWO Crystals
LA-SiPM readout, 2x1cm2
σ(E)/E~1.5%/√E + const.
End cap
4000 PWO crystals
High occupancy in center
LA-SiPM or VPT
PANDA PWO Crystals
PWO is dense and fast
Low γ threshold
Increase light yield:
- operation at -25°C (4xCMS)
Challenges:
- temperature stable to 0.1°C
- control radiation damage
- low noise electronics
Delivery of crystals started
PANDA – Calorimeter
52
Forward spectrometerTarget spectrometer
Barrel tile hodoscope
Time resolution: (50...100) psScintillator slabs or
pads of multigap resistive plate chambers (RPC)
Scintillator wall
Scintillator slabsTime resolution: ~ 50 ps
Quad module
Scintillator
SiPM
PANDA – Time-of-flight systems
Detector 53
Detector arrangement
54Detector
Cross section
55Detector
Cross section
56Detector
Luminosity
Interaction with matter
hadroncomptonphotoeffpairradcolltot dx
dE
dx
dE
dx
dE
dx
dE
dx
dE
dx
dE
dx
dE
57
58
Interaction of particles with matter
hadroncomptonphotoeffpairradcolltot dx
dE
dx
dE
dx
dE
dx
dE
dx
dE
dx
dE
dx
dE
som
e ex
amp
les
Bethe-Bloch Formula
Z
C
I
Tvmz
A
ZcmrN
dx
dE eeea 22
2ln2 2
2
max
22
2
222
][1535.02 1222 gMeVcmcmrN eea
222
222
max
)(121
2
M
m
M
m
cmT
ee
e
+++
Tmax head-on or knock-on collisions
59Detector
ZeVI )10(
mean excitation potential
Hans Bethe Felix Bloch
(Relativistic) charged particles other than electrons lose energy in matter
primarily by ionization and atomic excitation. The mean rate of energy loss
(or stopping power) is given by the Bethe-Bloch equation:
Mean excitation energies
60Detector
ICRU - International Commission on
Radiation Units and Measurements
Energetic knock-on electrons ( - rays):
The distribution of secondary electrons with kinetic energies T >> I
is given by:
22
22 )(1
2
1
T
TF
A
ZKz
dTdx
Nd
for I<<T≤Tmax
For example:
for a 500 MeV pion on a silicon detector with thickness x = 0.3mm,
on average one -ray (with 12 keV) is produced per particle crossing
integrating above Eq. from Tcut(=12 keV) toTmax
on average 0.0475 - ray (with 116 keV) are produced per particle
integrating Tcut (=116 keV) to Tmax
(116 keV is the mean energy loss in 0.3mm silicon for MIPs)61Detector
Mean energy loss rate
kinematical term 1/β2
MIPs ~3-4
relativistic rise ln(β22)
Z/A=1
Z/A~0.5
62Detector
Detector 63
Energy loss of muons
Fermi-plateau
Detector 64
Summary Bethe-Bloch
• BB valid for “heavy” particles ( m>~mµ)
• mean energy loss dE/dx normally given in MeVcm2/g
• dE/dx independent of the mass of the projectile
• Energy transfer within I < dE < Tmax
(I...mean excitation energy ~ 10·Z eV)
Detector 65
Mean range - range straggling
The range can be determine by passing a beam of particle with the
desired energy through different thicknesses of the material in question
and measure the ratio of transmitted to incident particles.
Detector 66
Bragg curve and mean range
intensity as
function of x
Energy loss
per length unit
Bragg peak
The energy loss of a charged particle passing an absorber is rising, most
of the energy is deposited at the “end” (important for radiotherapy)
Integration of the Bethe-Bloch formula gives
the mean range <R>:dE
dE
dxR
E0
Range of charged particles in matter
67DetectorR....mean range
M...mass of projectile
68Detector
For thin layers or low density materials:
Few collisions, some with high energy transfer
Energy loss distributions show large
fluctuations towards high losses:
”Landau tails”
For thick layers and high density materials:
Many collisions
Central Limit Theorem , Gaussian shaped
distributions
• Real detectors (limited granularity) can not measure <dE/dx> !
• In a detector the deposited energy ΔE in a layer of finite thickness x
is measured.
Interaction of charged particles
69Detector
Energy loss of electrons and positrons
Like heavy particles electrons and positrons also suffer collisional
energy loss when passing through matter.
But also, because of their small mass, an additional energy loss
mechanism comes into play: the emission of electromagnetic radiation
arising from scattering in the electric field of the nucleus
(bremsstrahlung).
collradtot dx
dE
dx
dE
dx
dE
+
Classically: bremsstrahlung can be explained as deviation of the
electron from its straight-line caused by the electric attraction of the
nucleus field.
Detector 70
Collision loss
For electrons the Bethe-Bloch formula has to be modified:
• the assumption that the incident particle remains un-deflected during
the collision process is not valid (due to the small e mass)
• for electrons the collisions appear between identical particles,
therefore their indistinguishability has to take into account
+
+
Z
CF
cmIA
ZcmrN
dx
dE
e
eea 2)()/(2
)2(ln
12
22
2
2
22
with the kinetic energy of the incident electron/positron in units mec2
))2(
4
)2(
10
)2(
1423(
122ln2)(
)1(
2ln)12(8/1)(
32
2
2
22
++
++
++
+
++
ßF
rßF for electrons
for positons
71
Energy loss by radiation - Bremsstrahlung
At energies below a few hundred GeV electrons and positrons are the
only particles for which radiation contributes substantially to the
energy loss of the particle.
e.g. for muons (m = 106 MeV) the radiation loss is ~ 40000 times
smaller than for electrons
Detector 72
Energy loss of electrons in copper
Detector 73
Radiation length
Is defined as the distance over which the electron energy is reduced
by a factor 1/e due to radiation loss:
0/
0
XxeEE
dxNE
dErad
x....travelled distance
X0..radiation length
74
Interaction of photons
The behaviour of photons in matter is quite different from
that of charged particles, as photons have no electric
charge there are no inelastic collisions with atomic
electrons.
The main interactions of X-rays and -rays in matter are:
• photoelectric effect
• Compton scattering
• pair production
Detector 75
Photoelectric effect
Photoelectric cross
section for lead
The photoelectric effect involves the absorption of a photon by an atomic
electron and the subsequent ejection of the electron from the atom.
The energy of the outgoing electron is : E = h - B.E.
Detector 76
scattering on a quasi-free e-
Compton scattering
Klein-Nishina formula used to
calculate Compton scattering
cross section
Energy distribution of Compton recoil electrons
Compton edge
W.R. Leo, Techniques for Nuclear andParticle Physics Experiments
Detector 77
Pair productionThe process of pair production involves the
transformation of a photon into an electron-positron pair.
In order to conserve momentum, this can occur only in
the presence of a third body (e.g. nucleus).
54
1
Z
183ln
9
7Zr4
3/1
22
enucl,pair
22 cmE epair production
cross section in
lead
W.R. Leo, Techniques for Nuclear andParticle Physics Experiments
54
109
cm
E2ln
9
7Zr4
2
e
22
enucl,pair
3/12
e Z
1
cm
E:for
3/12
e Z
1
cm
E:for
Photoelectric effect
→ Z4 to Z5 → E-3.5 to E-1
Compton scattering
→ Z → E-1
Pair production
→ Z2 → ln E
78Detector
photoelectric
Compton
pair
Total photon absorption cross section in lead
W.R. Leo, Techniques for Nuclear andParticle Physics Experiments
79Detector
The photon mass attenuation length
)/exp(0 tII
80Detector
Interaction of neutrons
81
Interaction of neutrons
