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Solid State Detectors. T. Bowcock. 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. Schedule. Time and Position Sensors.
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Solid State Detectors T. Bowcock
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 Schedule
Time and Position Sensors • History and Application to Particle Physics • Aim • Background • Basic Detector Concepts
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 e’s(1927) C. Davisson 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
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..."
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
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
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
1947-1953 • 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 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
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
CERN LEP-1984-1999 SC 1957-1990 Synchrotron Radiation
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
Cloud Chambers Emulsion Solid State Spark Chambers MWPC Bubble Chambers Drift Chambers Detector Technology 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Cloud Chamber • Supersaturated Gas • Cloud formation • Used until 1950’s • Build your own… • Properties
+ - - + - + + + - - - + - + - + - + + - - + + - - - + Ionisation • Charged particles • interaction with material “track of ionisation”
Emulsion • Dates back to Bequerel (1896) • Three components • silver halide (600mm thick) • plate • target • Grain diameter 0.2mm • Still the highest resolution device
Emulsion m First s event Scale 100mm
Emulsion • Still used • developed • scanned • computers help • very accurate • very slow • Needs to be combined with active spectrometer
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
Bubble Chamber • Gargamelle • late 1960’s • Volume=12m3 • magnet field • measure p • 4p acceptance!
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
Ionisation Density of electrons • Important for all charged particles • Bethe-Bloch Equation velocity Problem: Program this yourselves! Mean ionisation potential (10ZeV)
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...
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 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 + + + + + +
Spark Chambers • Gas • see into it • Particle tracking • Cheap • Fast(Pestov) • Large Signal
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)
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
Streamer Chamber • 1991 • ions
Proportional Tubes • Cylindrical tube and wire • Near the anode wire large field • Run below Geiger Threshold • signal proportional to initial ionisation ra + ri -
Multiwire Proportional Chamber (MWPC) • Charpak discovered if you put many wires together act as separate detectors .. anodes Cathode plane
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!
Ramo’s Theorem(1939) • quasistatic calculation k Vk V1 q 1 Problem for Students: prove Ramo’s Theorem<1 page
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?
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?
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
High Spatial ResolutionDetectors • Solid State Detectors • principles of operation • strip detectors • drift detectors • pixel detectors • CCD’s • advantages and shortcomings • methods of fabrication