Detectorsdetectors

Detectorsdetectors

HistoryHistory ofof InstrumentationInstrumentation Artist's View of a Bubble Chamber by a CERN physicist 1st EIROForum School on Instrumentation – History of Instrumentation Michael Hauschild - CERN, 11-May-2009, page 1 TimelineTimeline ofof ParticleParticle PhysicsPhysics andand InstrumentationInstrumentation 1895 1911 1932 1947 1960ies 1975 X-rays Atomic Nucleus Neutron Pion El.-weak Th. Tau W. C. Röntgen E. Rutherford J. Chadwick C. Powell S.L. GlashowM. Perl Positron Kaon A. Salam C. D. Anderson G. Rochester S. Weinberg 1896 1920 1936 1950 1973 1982/83 Radioactivity Isotopes Muon QED Neutral W/Z Bosons H. Becquerel E.W. Aston C. D. Anderson R. Feynman Currents C. Rubbia J. Schwinger S. Tomonaga 1899 1920ies 1956 1974 Electron Quantum Mechanics Neutrino J/y J. J. Thompson W. Heisenberg F. Reines B. Richter E. Schrödinger S.C.C. Ting P. Dirac 1934 1900 Photomultiplier 1950 1968 1983 H. Iams MWPC Silicon Strip Det. B. Salzberg C. Charpak J. Kemmer R. Klanner B. Lutz 1911 1929 1952 1974 Cloud Chamber Coincidences Bubble Chamber TPC C. T. R. Wilson W. Bothe D. Glaser D. Nygren 1928 1971 Geiger-Müller Drift Chamber 1903 tube 1937 A. H. Walenta Spinthariscope H. Geiger Nuclear Emulsion J. Heintze W. Crookes W. Müller M. Blau B. Schürlein 1st EIROForum School on Instrumentation – History of Instrumentation Michael Hauschild - CERN, 11-May-2009, page 2 EarlyEarly ImageImage DetectorsDetectors Second half of 19th century growing interest in meteorological questions climate, weather phenomenon, cloud formation people started to study condensation of water vapour in the lab also motived by raising use of steam engines John Aitken built a “Dust Chamber” 1888 water vapour mixed with dust in a controlled way Dust Chamber 1888 result: droplets are formed around dust particles further speculations electricity plays a role (from observations of steam nozzels) Charles T. R. Wilson became interested first ideas to build a cloud chamber 1895 to study influence of electricity/ions also to solve question why air shows natural slight conductivity 1st EIROForum School on Instrumentation – History of Instrumentation Michael Hauschild - CERN, 11-May-2009, page 3 CloudCloud ChamberChamber II Cloud chamber (1911 by Charles T. R. Wilson, Noble Prize 1927) chamber with saturated water vapour charged particles leave trails of ions water is condensing aound ions m u e s visible track as line of small water droplets u M e c n e i c S K U Also required Charles T. R. Wilson high speed photographic methods invented by Arthur M. Worthington 1908 to investigate the splash of a drop ultra short flash light produced by sparks First photographs of a-ray particles 1912 1st EIROForum School on Instrumentation – History of Instrumentation Michael Hauschild - CERN, 11-May-2009, page 4 X-ray 1 st EIROForum School EIROForum on InstrumentationHistory – of Instrumentation Michael Hauschild 11-May-2009,- CERN, page (Nobel Prize 1927together with Charles T. R. Wilson) (Compton effect) electrons on of photons scattering to discover 1922 in chamber Arthur cloud the ComptonH. used original photograph photograph original g X-rays emitted into cloud chamber effect again effect effect Compton or photo visible by angle certain under energy with reduced photon chamber) cloud in seen electron (recoiling electrons on scattered photon g + e + e g ' ® g ' + e Cloud Chamber II Cloud Chamber II ' γ e – Nobel Lecture 1927 Arthur H. Compton Compton H. Arthur 5 Nobel Lecture 1927 CloudCloud ChamberChamber IIIIII Paul Dirac Was also used for the discovery of the positron predicted by Paul Dirac 1928 (Nobel Prize 1933) found in cosmic rays by Carl D. Anderson 1932 (Nobel Prize 1936) Anderson also found the muon in 1936, downward going positron, 63 MeV the first 2nd generation particle in the Standard Model Isidor Isaac Rabi said: Carl D. Anderson “Who ordered that?” 6 mm lead plate positron is loosing 1.5 T magnetic field energy in lead, 23 MeV at exit ® smaller radius, this defines the track direction! 1st EIROForum School on Instrumentation – History of Instrumentation Michael Hauschild - CERN, 11-May-2009, page 6 NuclearNuclear EmulsionEmulsion II Pioneered by Marietta Blau between Marietta Blau 1923 – 1938 (no Nobel Prize) photographic emulsion layer, 10 – 200 µm thick, uniform grains of 0.1 – 0.3 µm size very high resolution for particle tracks analysis of developed emulsion by microscope nuclear disintegration from cosmic rays, observed1937 for the first time Since early 20th century important role of photography to study radioactivity but capability to make individual tracks visible not seen until nuclear emulsion technique was developed 1st EIROForum School on Instrumentation – History of Instrumentation Michael Hauschild - CERN, 11-May-2009, page 7 NuclearNuclear EmulsionEmulsion IIII Cecil Powell Discovery of the pion in cosmic rays by Cecil Powell 1947 (Nobel Prize 1950) Discovery of the kaon 1949 (G. Rochester) electron pion stops and decays muon muon stops pion and decays pion 100 µm other pion decays, kaon muon has always same length (energy) ® 2-body decay p ® m nm pion pion 1st EIROForum School on Instrumentation – History of Instrumentation Michael Hauschild - CERN, 11-May-2009, page 8 NuclearNuclear EmulsionEmulsion IIIIII CNGS beam Still used in actual experiments with highest precision requirements over a large volume nm beam sent from CERN to Gran Sasso Underground lab in Italy (732 km) OPERA experiment is searching for nt appearance after neutrino oscill. nm ® nt - need to reconstruct t decays (nt + N ® t + X) (few ~100 µm track length) 235'000 “bricks” (1.7 ktons) of lead + emulsion sheets t decay single brick bricks OPERA at Gran Sasso automatic emulsion scanning nm interaction 1st EIROForum School on Instrumentation – History of Instrumentation Michael Hauschild - CERN, 11-May-2009, page 9 BubbleBubble ChamberChamber II Donald Glaser Intented 1952 by Donald Glaser (Noble Prize 1960) similar to could chamber y r a r (“superheated”) b chamber with liquid (e.g. H ) at boiling point i 2 L e g a m I charged particles leave trails of ions L N B formation of small gas bubbles around ions L nm nm was used at discovery of the “neutral current” (1973 by Gargamelle Collaboration, no Noble Prize yet) Z0 e- e- 400 MeV electron nm N N R R E Gargamelle bubble chamber E C NOT this track... C 1st EIROForum School on Instrumentation – History of Instrumentation Michael Hauschild - CERN, 11-May-2009, page 10 BubbleBubble ChamberChamber IIII BEBC (Big European Bubble Chamber) at CERN, 1973 – 1984 largest bubble chamber ever built (and the last big one...), Æ 3.7 m 6.3 million photographs taken, 3000 km of developed film now displayed in permanent exhibition at CERN BEBC BEBC piston production of D* meson with long decay chain 1st EIROForum School on Instrumentation – History of Instrumentation Michael Hauschild - CERN, 11-May-2009, page 11 BubbleBubble ChamberChamber IIIIII Advantages of bubble chambers Mirror liquid is BOTH detector medium AND target high precision Disadvantages SLOW!!! Table event pictures taken with cameras on film Films (multiple views) film needs to be developed, shipped to institutes and projection system N and optically scanned for interesting events R E C Need FASTER detectors (electronic!) Scanning table (1972) However: Some important social side effects of bubble chamber era... scanning was often done by young “scanning girls” (students)... ...who later got married with the physicists... 1st EIROForum School on Instrumentation – History of Instrumentation Michael Hauschild - CERN, 11-May-2009, page 12 EarlyEarly “Electronic”“Electronic” DetectorsDetectors -- SpinthariscopeSpinthariscope 1911: Ernest Rutherford + studied (elastic) scattering of a particles on gold atoms (famous Rutherford experiment) discovery of atomic nucleus: small (heavy) positively charged nucleus orbited by electrons Zinc sulfide screen with microscope Hans Geiger Ernest Rutherford (spinthariscope by William Crookes 1903) m u e was used to detect scattered particles s a u M e c n e i light flash was observed by eye c S K to increase light sensitivity, “bella donna” U (from the deadly night shade plant = Tollkirsche) was often used to open eye's pupil deadly night shade 1st EIROForum School on Instrumentation – History of Instrumentation Michael Hauschild - CERN, 11-May-2009, page 13 EarlyEarly ElectronicElectronic DetectorsDetectors -- ElectroscopeElectroscope Gold-leaf electroscope already invented 1787 by Abraham Bennet End of 19th century raising interest on electricity in gases cathode ray tubes, glow discharges observation: early cathode ray tube charged electroscope is loosing its charge in dry air after some time source of conductivity? ionisation by recently discovered radioactivity? Victor Hess discovered cosmic rays 1912 (Nobel Prize 1936) used calibrated string electrometer Victor Hess by Theodor Wulf in balloon found increasing ionisation at higher altitudes at a series of balloon ascents not related to sun radiation! pair of wires 1st EIROForum School on Instrumentation – History of Instrumentation Michael Hauschild - CERN, 11-May-2009, page 14 Geiger-MüllerGeiger-Müller TubeTube The Geiger-Müller tube (1928 by Hans Geiger and Walther Müller) Tube filled with inert gas (He, Ne, Ar) + organic vapour Central thin wire (20 – 50 µm Æ) , high voltage (several 100 Volts) between wire and tube Strong increase of E-field close to the wire - electron gains more and more energy above some threshold (>10 kV/cm) + electron energy high enough to ionize other gas molecules newly created

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