Detectors for Particle Physics

Transcription

1 Introduction Dtctors for Particl Physics DESY Summr Studnt Lcturs 2004 Carstn Nibuhr CMB: T = 2.72 K, T=3mK n γ = 4 x 10 8 m -3 carstn.nibuhr@dsy.d 1 Particl Dtctors 1 carstn.nibuhr@dsy.d 2 Particl Dtctors 1 Litratur Txtbooks: K.Klinkncht: Dtctors for Particl Radiation Cambridg Univrsity Prss, 1998 W.R. Lo: Tchniqus for Nuclar and Particl Physics Exprimnts Springr 1994 G.F.Knoll: Radiation Dtction and Masurmnt Wily, 3rd dition D.Grn: Th Physics of Particl Dtctors Cambridg Univrsity Prss, 2000 C.Grupn: Particl Dtctors Cambridg Univrsity Prss, 1996 W.Blum, L.Rolandi: Particl Dtction with Driftchambrs Springr, 1994 Ovrviw articls: T.Frbl: Exprimntal Tchniqus in High Enrgy Physics Addison-Wsly 1987 Othr sourcs: Particl Data Group: Rviw of Particl Physics Eur. Phys. J. C15, (2000) R.K.Bock, A.Vasilscu: Th Particl Dtctor BrifBook Springr, 1998 and //physics.wb.crn.ch/physics/particldtctor/brifbook/ Furthr Sourcs on th Wb DETECTOR PHYSICS and APPLICATIONS CENTER - DPAC CERN Summr Studnt Lctur Programm Lctur Nots by Hlmuth Spilr Vorlsungsskript D.Wgnr Dortmund (in grman) Transprancis of Dtctor Lctur C.N. (in grman) carstn.nibuhr@dsy.d 3 Particl Dtctors 1 carstn.nibuhr@dsy.d 4 Particl Dtctors 1

2 Topics of th Lctur What ar th Objcts? Part I Introduction Exampls Part II Us of Track Dtctors for Momntum Masurmnt Part III Scintillation Countrs Photodtctors Gnral Concpts Intraction of Chargd Particls with Mattr - Enrgy Loss: Bth Bloch Formula - Multipl Scattring Gas Dtctors Chrnkov Countrs - Proportional Chambr - Drift Chambr Transition Radiation - TPC - MSGC, GEM Calorimtrs - Showr Dvlopmnt Silicon Dtctors - lctromagntic - Strip Dtctors - hadronic - Pixl Dtctors not covrd - Triggr - DAQ and many mor... carstn.nibuhr@dsy.d 5 Particl Dtctors 1 carstn.nibuhr@dsy.d 6 Particl Dtctors 1 Fundamntal Intractions Rcntly obsrvd Rsonanc at HERA Pntaquark Candidat: θ 0 c D * p K π + π p minimal quark contnt: uuddc sofar only sn by H1... Exampl ρ 0 π + π π 0 γγ K 0 π + π Liftim [s] cτ [mm] 3x x carstn.nibuhr@dsy.d 7 Particl Dtctors 1 carstn.nibuhr@dsy.d 8 Particl Dtctors 1

3 Dtction of Particls and Radiation Th goal of xprimntal particl physics: masurmnt of - particl proprtis - raction probabilitis ( cross sctions) This rquirs dtrmination of: - particl typ (mass, charg, spin tc) - momntum / nrgy of particl - mission angls Elmnts contributing to such masurmnts : position snsitiv dtctors position, dirction dflction in magntic fild p calorimtry: total nrgy absorption and masurmnt E tot mass dtrmination m Chrnkov radiation or tim of flight β transition radiation γ Critria for Idal Dtctor Bcaus in gnral thr can b vry complx vnt topologis on oftn nds: rconstruction of full vnt kinmatics (background rjction) Most important: high fficincy high rsolution high accptanc covrag of full solid angl (4π) also vry important (partly conflicting dmands): particl idntification capability fast rspons high rat capability no dad tim hrmticity no aging high rliability good accssibility low cost carstn.nibuhr@dsy.d 9 Particl Dtctors 1 carstn.nibuhr@dsy.d 10 Particl Dtctors 1 Modrn Collidr Dtctors Som Particl Physics Exprimnts Bsids th larg collidr dtctors thr ar many othr xpts: in opration LHC Dtctors: undr construction TESLA dtctor: undr R&D Bats Linar Acclrator (MIT) BLAST, OOPS, SAMPLE Bijing IHEP ARGO-YBJ, BES, Tibt ASgamma Brookhavn BRAHMS, Crystal Ball (E913/914), E787, E821/muon g-2, E850, E852, E863/ EMU01, E864, E865, E869, E877, E881, E885, E890, E891, E895, E905, E906, E907, E909, E910, E913/914 (Crystal Ball), E917, E923, E926, E927, E949, E953, EIC, EMU01/E863, High Gain Harmonic Gnration FEL, ICAE, IFEL, IMB, LEGS, MECO, Microundulator FEL, NuMass/E952, PHENIX, PHOBOS, pp2pp, Smith-Purcll, STAR, Zro Dgr Calorimtr CERN ALEPH, ALICE, AMS, ANTARES, ASACUSA, ATHENA, Atlas (Europan), ATRAP, CDHS nutrino xprimnt/wa1, CERES/NA45, CHORUS, CMS, CosmoLEP, CPLEAR/PS195, Crystal Barrl/PS 197, Crystal Clar/RD18, DELPHI, EMU01, FELIX, HARP, ICANOE, ISOLDE, L3, LHC-B, MISTRAL, NTOF1, NTOF2, NTOF3, NA45.2/IONS/EL.PAR, NA47/SMC, NA48, NA48.1, NA48.2, NA49, NA50, NA51, NA52/ Nwmass, NA56/SPY, NA57, NA58/COMPASS, NA59, NA60, NOMAD, OBELIX/PS201, OPAL, OPERA, PAMELA, PS185, PS205/HELIUMTRAP, PS210, PS212/DIRAC, PS214/HARP, RD8, RD11, RD12/TTC, RD13, RD27, RD39/SMSD, RD41/ MOOSE, RD42, RD44/Gant 4, RD45, RD46, RD48/ ROSE, RD49/RADTOL, TOSCA, TOTEM, WA85, WA92 (Batric), WA94, WA97, WA98, WA102 DESY H1, HERA-B, Hrms, TESLA, ZEUS Frmilab Antihydrogn/E862, APEX/E868, Augr Projct, BooNE/E898, BTEV/C0, CDF/E830, CDMS/E981, CEX/E853, Charmonium/E835, CMS (US Srvr), COSMOS/E803, D0 (DZro)/E823, Donut/E872, E665, E771, E789, Frmi III Projct, FOCUS/E831, HyprCP/E871, KTEV/E799/E832, MINOS/E875, NuMI, NUSEA/E866, NuTV/E815, SDSS, SELEX/ E781, Zro Dgrs/C0 Gran Sasso BOREXino, CRESST, CUORICINO, DAMA, EASTOP, GALLEX(finishd), GENIUS, GNO, Hidlbrg Dark Mattr Sarch (HDMS), Hidlbrg-Moscow Exprimnt, ICARUS, LUNA, LVD, MACRO, MONOLITH, NOE, OPERA, USA carstn.nibuhr@dsy.d 11 Particl Dtctors 1 carstn.nibuhr@dsy.d 12 Particl Dtctors 1

4 Sarch for Rar/Forbiddn Dcays Exprmimnt in prparation at Paul Schrrr Institut (Switzrland): Sarch for lpton-numbr violating procss: µ γ nds xcllnt nrgy rsolution, small track multiplicitis ALICE at LHC Havy Ion Physics: this simulation shows 1/10 of all xpctd tracks in a typical vnt. Th sparation of all ths tracks puts high dmands on th position rsolution of th dvic Liq. X Scintillation Dtctor Liq. X Scintillation Dtctor Thin Suprconducting Coil Muon Bam? Stopping Targt? + Timing Countr + Drift Chambr Drift Chambr 1m carstn.nibuhr@dsy.d 13 Particl Dtctors 1 carstn.nibuhr@dsy.d 14 Particl Dtctors 1 Supr-Kamiokand (Japan) Satllit basd Dtctors Sarch for proton-dcay and for nutrino oszillations tons of watr photo tubs Launch schduld for 2006 GLAST Gamma-Ray obsrvatory for high nrgy photons in th rang 20MV to >300 GV Astro particl physics acclration mchanism of AGN s idntification of sourcs Ractions : ν µ N µn Chrnkov ν N N showr Componnts (highst rliability!) prcision trackr (Si-strips) calorimtr (CsI(Tl)) data acquisition systm anticoincidnc dtctor carstn.nibuhr@dsy.d 15 Particl Dtctors 1 carstn.nibuhr@dsy.d 16 Particl Dtctors 1

5 Applications in Mdicin Intrplay btwn Physics and Tchnology Imaging microgap dtctor: Photon rats 10 6 mm -2 s -1 Almost all ffcts usd in particl dtctors ar basd on th lctromagntic intraction only. Most modrn dtctors convrt th absorbd nrgy into an lctrical signal. Th dtction snsitivity and prformanc dpnds on fluctuations in th dtctor fluctuations in th lctronics Undrstanding of.g. a modrn tracking dtctor in high-nrgy physics or a mdical imaging systm thus rquirs knowldg of solid stat physics smiconductor dvic physics smiconductor fabrication tchnology NIKOS Non-invasiv Koronary Angiography using synchrotron radiation To maximiz dtction snsitivity and rsolution on must considr signal formation in th dtctor coupling of th dtctor to th radout lctronics fluctuations in th lctronics low-nois lctronics tchniqus analog and digital microlctronics high-spd data transmission computr-basd data acquisition systms carstn.nibuhr@dsy.d 17 Particl Dtctors 1 carstn.nibuhr@dsy.d 18 Particl Dtctors 1 Intraction of Radiation with Mattr Chargd Particls Nutral Particls havy chargd particls nutrons Cross Sction of Typical Collidr Dtctor Particl typ: - nutrinos (missing nrgy) - muons µ - hadrons: p, π, K... [quarks, gluons jts] absorbr (mostly F) flux rturn yok havy mdium (F, Cu, U) + activ matrial lctrons gamma radiation - lctrons, photons - chargd particls Coulomb-Intraction with lctrons of mdium nutrinos Mainly singular intractions, rsulting in nrgy transfr to chargd particls Rough classification track dtctors for chargd particls: - gas dtctors - solid stat dtctors calorimtr for nrgy masurmnt - lctromagntic - hadronic masslss dtctors magnt coil (solnoid, fild bam axis) high Z matrial (Pb) carstn.nibuhr@dsy.d 19 Particl Dtctors 1 carstn.nibuhr@dsy.d 20 Particl Dtctors 1

6 Exampl 1: HERA p Evnt Exampl 2: Muons p Jt 1 Jt 2 Jt 3 hadronic calorimtr lctromagn. calorimtr track dtctor transvrs viw: Bcaus of thir larg mass (compard to lctrons) muons can pntrat calorimtr and iron yok µ µ 27.5 GV 920 GV p p trans = 0 i almost hrmtic dtctor dtction of narly all producd particls sid viw xploit nrgy- and momntum consrvation µ µ carstn.nibuhr@dsy.d 21 Particl Dtctors 1 carstn.nibuhr@dsy.d 22 Particl Dtctors 1 Exampl 3: Nutrinos Exampl 4: Scondary Vrtics ν p Msons containing havy quarks (charm or bauty) can dcay via th wak intraction. xampl: D K + π π Rsulting liftims ar rlativly long: Missing transvrs nrgy and transvrs momntum: i p trans = 43GV 2 m K + π π D 50 cm τ O(10-12 s) or cτ µm With th hlp of high prcision track dtctors on can distinguish if particls originat from scondary or primary vrtx: carrid away by nutrino? 5 cm 5 mm vrtx dtctors [in most cass basd on silicon] carstn.nibuhr@dsy.d 23 Particl Dtctors 1 carstn.nibuhr@dsy.d 24 Particl Dtctors 1

7 Intraction of Chargd Particls Thr ar two principal ffcts which charactriz th passag of chargd particls through mattr: - nrgy loss - chang of dirction both ffcts rsult from th following lctromagntic procsss: - inlastic collisions with shll lctrons of mdium - lastic scattring off nucli rlvant is th statistical sum of many such intractions. In addition thr ar th following procsss: - brmsstrahlung - mission of Chrnkov radiation - nuclar ractions - mission of transition radiation which howvr in gnral occur much lss frqunt than atomic collisions. For chargd particls on must distinguish light particls ( +, ) and havy particls (i.. all th rst: µ, π,p, α, light nucli) Enrgy loss by ionisation: de πN dx A r 2 m c 2 z 2Z Ā -- 1 = Bth-Bloch Formula incidnt particl - β = v c vlocity of particl - z charg of particl mdium - Z, A of mdium - I 16 Z 0.9 avrag ionisation potntial in [V] - δ dscribs dnsity ffct du to polarisation of mdium ( saturation of rlativistic ris) othr constants - N A Avogadro s numbr - r = 2.8 fm classical lctron radius - m lctron mass β 2 2m c 2 β 2 γ 2 ln β I 2 δ -- 2 Proprtis: [MV/cm] dpndnc only on particl vlocity not on particl mass at small nrgis - drops lik 1 β 2 at rlativistic nrgis i.. - logarithmic ris lnβγ = E fild βγ» 1 lne at rst γ > 1 approximat rang of validity: 10MV/c p 50GV/c carstn.nibuhr@dsy.d 25 Particl Dtctors 1 carstn.nibuhr@dsy.d 26 Particl Dtctors 1 Matrial Dpndnc de/dx Application for Dtctors 10 8 Enrgy loss is a function of Z/A, I, and th dnsity ρ. Hnc us instad : Gas de/dx (MV g 1 cm 2 ) βγ = p/mc Muon momntum (GV/ c) 0.1 H 2 liquid H gas Al F Sn Pb Pion momntum (GV/ c) C de 1 de X = x ρ = [MV g - 1 cm 2 ]. dx ρ dx de/dx ssntially a function of Z/A de/dx min (MV g 1 cm 2 ) H 2 gas: 4.10 H 2 liquid: 3.97 Solids Gass "Stopping Powr" log 10 (Z) ionisation proportional/drift chambr Liquid local hating bubbl chambr ionisation (LAr, LKr) calorimtr Solid Stat xcitation of lctrons convrsion into light scintillators Proton momntum (GV/ c) logarithmic ris mor pronouncd for gass (H) 0.5 H H Li BB CNON F Sn Z cration of lctron-hol pairs solid stat dtctors carstn.nibuhr@dsy.d 27 Particl Dtctors 1 carstn.nibuhr@dsy.d 28 Particl Dtctors 1

8 de/dx for diffrnt Particl Spcis Proprtis of som Matrials (PDG) de/dx (kv/cm) Masurmnts in PEP4/9-TPC (Ar-CH 4 = 8.5atm) µ π K p D Momntum (GV/c) If de/dx is plottd vrsus momntum of particl th curvs ar shiftd for diffrnt masss Application: if also th momntum of th particl is known th masurmnt of th spcific ionisation can b usd for particl idntification In this xampl ach dot rprsnts 185 singl masurmnts in a drift chambr Matrial Z A Z/A Nuclar a Nuclar a de/dx b min Radiation lngth c { } collision intraction X MV 0 lngth λ T lngth λ I {g/cm 2 } {g/cm 2 g/cm 2 {g/cm 2 }{cm} } Dnsity {g/cm 3 } ({g/l} for gas) Liquid Rfractiv boiling indx n point at ((n 1) atm(K) for gas) H 2 gas (4.103) d (731000) (0.0838)[0.0899] [139.2] H 2 liquid d D (2.052) [0.179] [138] H (1.937) [0.1786] [34.9] Li B C N (1.825) [1.250] [298] O (1.801) [1.428] [296] F (1.675) [1.696] [195] N (1.724) [0.9005] [67.1] Al Si Ar (1.519) [1.782] [283] Ti F Cu G Sn X (1.255) [5.858] [701] W Pt Pb U Air, (20 C, 1atm.), [STP] (1.815) [30420] (1.205)[1.2931] 78.8 (273) [293] H 2O CO 2 gas (1.819) 36.2 [18310] [1.977] [410] carstn.nibuhr@dsy.d 29 Particl Dtctors 1 carstn.nibuhr@dsy.d 30 Particl Dtctors 1 Multipl Scattring Summary z,β log scal! θ Scattring of chargd particls off th atoms in th mdium causs a chang of dirction: th statistical sum of many such small angl scattrings rsults in a gaussian angular distribution with a width givn by: θ 0 = 13.6MV z βpc x X 0 ln x xampl: p = 1 GV/c, d = 300µm Si, X 0 =9.4cm θ mrad for 10cm distanc this mans 80µm! th lss likly scattring off th atomic nucli causs larg scattring angls rsulting in a dviation from a gaussian distribution at larg angls X 0 proprtis of diffrnt particls rquirs many diffrnt typs of dtctors rough classification - track/position dtctors (non dstructiv) Part II - calorimtrs (dstructiv) Part III basically all dtctors basd on lctromagntic intraction dtctors also mor and mor usd for othr applications (.g. mdical appl.) nrgy loss of chargd particls: Bth Bloch - z 2 β 2 lne Frmiplatau - minimum at βγ 3: 1-2 MV pr gcm -2 multipl scattring 1 x - gaussian distribution: angular sprad θ p X 0 - dviation du to larg angl scattring (nucli) carstn.nibuhr@dsy.d 31 Particl Dtctors 1 carstn.nibuhr@dsy.d 32 Particl Dtctors 1