Transcript Solid State Detectors - Laboratoire de Physique des Hautes

Solid State
Detectors
T. Bowcock
Schedule
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Time and Position Sensors
Principles of Operation of Solid State
Detectors
Techniques for High Performance
Operation
Environmental Design
Measurement of time
New Detector Technologies
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Time and Position
Sensors
• History and Application to Particle
Physics
• Aim
– Background
– Basic Detector Concepts
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Chronology of Discoveries
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1900
Electron (1897)
J.J. Thompson
Cloud Chamber(1912)
C.T.R.Wilson
Cosmic Rays(1913) V.F.Hess &C.Anderson
Discovery of Proton(1919)
E. Rutherford
Compton Scattering (1923)
C.T.R.Wilson
Waves nature of e’s(1927)
C. Davisson
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Beginning...
Geiger&Marsden
source
Zinc Sulphide Screen
E. Rutherford
1927, Rutherford, as President of the Royal Society, expressed a wish
for a supply of "atoms and electrons which have an individual energy far
transcending that of the alpha and beta particles from radioactive
bodies..."
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Cross-Section
1 barn=10-24 cm2
approximately the area of
a proton
Distribution of scattering
angles tell us about the
force/particles
Precision required
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Accelerator technology
The first successful
cyclotron, built by
Lawrence and his
graduate student M.
Stanley Livingston,
accelerated a few
hydrogen-molecule ions
to an energy of 80,000
electron volts. (80KeV)
1932- 1MeV
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1932-1947
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1900
Neutron(1932)
J. Chadwick
Triggered Cloud Chamber(1932) P.Blackett
Muon(1937)
S.H. Neddermeyer
Muon Decay(1939)
B.Rossi, Williams
Kaon(1944)
L. Leprince-Ringuet
Pion(1947)
.H.Perkins,G.P.S.Occialini
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1947-1953
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1900
Scintillation Counters(1947)
F. Marshall
pion decay(1947)
C. Lattes
Unstable V’s(1947)
G.D.Rochester
SemiConductor Detectors(1949) K.G.McKay
SparkChambers(1949)
J.W.Keuffel
K Meson(1951)
R. Armenteros
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1953-1968
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1900
Neutrino (1953)
Bubble Chamber(1953)
K+ Lifetime(1955)
Flash Tubes(1955)
Spark Chamber(1959)
Streamer Chambers(1964)
MWPC(1968)
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F. Reines
D.A. Glaser
L.W.Alvarez
M. Conversi
S. Fukui
B.A.Dolgoshein
G. Charpak
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1980
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CERN
LEP-1984-1999
SC 1957-1990
Synchrotron
Radiation
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1968-1999
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1900
J/ (charm) (1974) J.J, Aubert, J.E. Augustin
t lepton(1975)
M.Perl et al
B-mesons(1981)
CLEO
W,Z(1983)
UA1
number of n (1991)
L3
t-quark(1994) First major discovery with Solid CDF
State Detectors
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Detector Technology
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Emulsion
Cloud Chambers
Spark Chambers
MWPC
Drift Chambers
Bubble Chambers
Solid State
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Cloud Chamber
• Supersaturated
Gas
• Cloud formation
• Used until 1950’s
• Build your own…
• Properties
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Ionisation
• Charged particles
– interaction with
material
-+
+-+
-+
-+
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-+
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+ -+
-+
+
+-“track of ionisation”
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Cloud Chamber
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Emulsion
• Dates back to Bequerel (1896)
• Three components
– silver halide (600mm thick)
– plate
– target
• Grain diameter 0.2mm
– Still the highest resolution device
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Emulsion
m
First s event
Scale 100mm
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Emulsion
• Still used
– developed
– scanned
• computers help
– very accurate
– very slow
• Needs to be combined with active
spectrometer
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Bubble Chamber
• Superheated
Liquid e.g. H2
– -253C
– 1954 d=3.4cm
– 1957 d=180cm
• Bubbles form
around ions
• 10mm in O(ms)
sketch dated January 25th, 1954
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Bubble Chamber
• Gargamelle
– late 1960’s
• Volume=12m3
• magnet field
– measure p
• 4p acceptance!
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Bubble Chamber
• First Neutral
Current Event (Z0)
seen in Gargamelle
• Bubble density
measures velocity
– b <0.8
• Use limited...
Physics Letters, 46B, 138 (1973)
– Cannot use in a storage ring
– slow cycle time and difficult to trigger
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Ionisation
Density of electrons
• Important for all
charged particles
dE Dne   2mc2 b 2 2 
 ( ) 
2



 2 ln 
b  2 
dx
b  
I


• Bethe-Bloch Equation
velocity
Mean ionisation potential
(10ZeV)
Problem: Program this
yourselves!
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Ionisation
• Most of our discussion on minimum
ionising paritcles (MIPS)
• Note essentially the same process in
gas, liquid or solid
• Using ions to “nucleate”
physics/chemical changes
– need to observe these changes
• however...
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Ionisation
• In low fields the ions eventually
recombine with the electrons
• However under higher fields it is
possible to separate the charges
-+------------------------+-+- -- -- --- ----+------------------------+-+- -- -- --- ----+----- ---- ---------------+
E
Note: e-’s and ions
generally move at a
different rate
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Spark Chambers
• Gas
– see into it
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Particle tracking
Cheap
Fast(Pestov)
Large Signal
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Spark Chamber
HT
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Spark Chamber
• Highly efficient 95%
• High electron multiplication
– low electron affinity (Noble gases)
– high field
• Problems
– 30 ns pulses(high voltage spikes)
– resolution 300 mm
– long memory while ions clear (ms)
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Streamer Chamber
• “Electrical Bubble Chamber”
• Plasma forms along path of
particle
– streamers move at high velocity
– sort pulse leaves visible streamer
suspended
• 40-300 mm resolution
– triggerable
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Streamer Chamber
• 1991
– ions
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Proportional Tubes
E (r )  V0 /( r ln( ra / ri ))
• Cylindrical tube
and wire
• Near the anode
wire large field
• Run below Geiger
Threshold
– signal proportional
to initial ionisation
V (r )  ln r / ri 
ra
+
ri
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Multiwire Proportional
Chamber (MWPC)
• Charpak discovered if you put many wires
together act as separate detectors ..
anodes
Cathode plane
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Signal Generation
 
   qE.dr  q1   2 
2
• Note
1
• Change in energy is source of signal
• Most electrons produced close to
anode
– form of voltage means electrons do not
drop much voltage compared with ions
that see almost all!
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Ramo’s Theorem(1939)
i , 0
• quasistatic calculation
k
V1
1
i
Vk
 
v  Ei ( x1 )
I i  q
Vi
q
Problem for Students:
prove Ramo’s
Theorem<1 page
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Gas Detectors….
• Many different kinds of gas detectors
– in use
– large volume
– cheap
– high resolution (down to diffusion levels)
– lots of experimental results
• Why do we want Solid State
Detectors?
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Detectors
• Many mature technologies
– emulsions
– bubble chambers
– gas chambers
• Where next?
Question: what are
the advantages and
disadvantages of
each technology?
– High resolution
– reliable
• 50 years later Si!
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Summary Lecture 1
• Many types of detectors
• Use of ionisation from charged
particles
– nucleation
– separation of charge
• Signal Generation
– ideas we will use next lecture
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High Spatial Resolution
Detectors
• Solid State Detectors
– principles of operation
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strip detectors
drift detectors
pixel detectors
CCD’s
– advantages and shortcomings
– methods of fabrication
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