Solid State Detectors

1
Solid State Detectors

• T. Bowcock

2
Schedule

• 1 Time and Position Sensors
• 2 Principles of Operation of Solid State
• Detectors
• 3 Techniques for High Performance Operation
• 4 Environmental Design
• 5 Measurement of time
• 6 New Detector Technologies

3
Time and Position Sensors

• History and Application to Particle Physics
• Aim
• Background
• Basic Detector Concepts

4
Chronology of Discoveries

• 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 es(1927) C. Davisson

1900 1910 1920 1930 1940 1950
1960 1970 1980 1990 2000
5
Beginning...
GeigerMarsden
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..."
6
Cross-Section
1 barn10-24 cm2 approximately the area of a
proton
Distribution of scattering angles tell us
about the force/particles Precision required
7
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

• 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
  

1900 1910 1920 1930 1940 1950
1960 1970 1980 1990 2000
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1947-1953

• Scintillation Counters(1947) F. Marshall
• pion decay(1947) C.
  Lattes
• Unstable Vs(1947) G.D.Rochester
• SemiConductor Detectors(1949) K.G.McKay
• SparkChambers(1949) J.W.Keuffel
• K Meson(1951) R.
  Armenteros

1900 1910 1920 1930 1940 1950
1960 1970 1980 1990 2000
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1953-1968

• Neutrino (1953) F. Reines
• Bubble Chamber(1953) D.A. Glaser
• K Lifetime(1955)
  L.W.Alvarez
• Flash Tubes(1955) M.
  Conversi
• Spark Chamber(1959) S. Fukui
• Streamer Chambers(1964) B.A.Dolgoshein
• MWPC(1968) G.
  Charpak

1900 1910 1920 1930 1940 1950
1960 1970 1980 1990 2000
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CERN
LEP-1984-1999
SC 1957-1990
Synchrotron Radiation
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1968-1999

• 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)
  CDF

First major discovery with Solid State Detectors
1900 1910 1920 1930 1940 1950
1960 1970 1980 1990 2000
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Detector Technology
1900 1910 1920 1930 1940 1950
1960 1970 1980 1990 2000
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Cloud Chamber

• Supersaturated Gas
• Cloud formation
• Used until 1950s
• Build your own
• Properties

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Ionisation

• Charged particles
• interaction with material

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 d3.4cm
• 1957 d180cm
• Bubbles form around ions
• 10mm in O(ms)

sketch dated January 25th, 1954
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Bubble Chamber

• Gargamelle
• late 1960s
• Volume12m3
• 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 lt0.8
• 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

• Bethe-Bloch Equation

velocity
Problem Program this yourselves!
Mean ionisation potential (10ZeV)
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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

Note e-s and ions generally move at a different
rate


E






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Spark Chambers

• Gas
• see into it
• 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

• Cylindrical tube and wire
• Near the anode wire large field
• Run below Geiger Threshold
• signal proportional to initial ionisation

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

• Note
• 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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Ramos Theorem(1939)

• quasistatic calculation

k
Vk
V1
q
1
Problem for Students prove Ramos Theoremlt1 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?
• High resolution
• reliable
• 50 years later Si!

Question what are the advantages and
disadvantages of each technology?
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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 ResolutionDetectors

• Solid State Detectors
• principles of operation
• strip detectors
• drift detectors
• pixel detectors
• CCDs
• advantages and shortcomings
• methods of fabrication