Detectors for Particle Physics

Transcription

1 Introduction Dtctors for Particl Physics DESY Summr Studnt Lcturs 2003 Carstn Nibuhr CMB: T = 2.72 K, T=3mK n γ = 4 x 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 carstn.nibuhr@dsy.d 3 Particl Dtctors 1 carstn.nibuhr@dsy.d 4 Particl Dtctors 1

2 Fundamntal Intractions Modrn Collidr Dtctors LHC Dtctors: undr construction TESLA dtctor: undr R&D in opration 5 Particl Dtctors 1 carstn.nibuhr@dsy.d 6 Particl Dtctors 1 Slction of Particl Physics Exprimnts Sarch for Rar/Forbiddn Dcays Bsids th larg collidr dtctors thr ar many othr xpts: 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, E9, 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, PS2, 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, WA2 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 Exprmimnt in prparation at Paul Schrrr Institut (Switzrland): Sarch for lpton-numbr violating procss: µ γ nds xcllnt nrgy rsolution, small track multiplicitis Thin Suprconducting Coil Muon Bam Drift Chambr? + Stopping Targt Liq. X Scintillation Dtctor Timing Countr 1m? Liq. X Scintillation Dtctor + Drift Chambr carstn.nibuhr@dsy.d 7 Particl Dtctors 1 carstn.nibuhr@dsy.d 8 Particl Dtctors 1

3 ALICE at LHC Havy Ion Physics: this simulation shows 1/0 of all xpctd tracks in a typical vnt. Th sparation of all ths tracks puts high dmands on th position rsolution of th dvic Sarch for proton-dcay and for nutrino oszillations tons of watr photo tubs Supr-Kamiokand (Japan) Ractions : ν µ N µn Chrnkov ν N N showr carstn.nibuhr@dsy.d 9 Particl Dtctors 1 carstn.nibuhr@dsy.d Particl Dtctors 1 Satllit basd Dtctors Applications in Mdicin 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 Imaging microgap dtctor: Photon rats 6 mm -2 s -1 Componnts (highst rliability!) prcision trackr (Si-strips) calorimtr (CsI(Tl)) Data acquisition systm Anticoincidnc dtctor NIKOS Non-invasiv Koronary Angiography using synchrotron radiation carstn.nibuhr@dsy.d 11 Particl Dtctors 1 carstn.nibuhr@dsy.d 12 Particl Dtctors 1

4 Intrplay btwn Physics and Tchnology Dtction of Particls and Radiation 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 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 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 low-nois lctronics tchniqus analog and digital microlctronics high-spd data transmission computr-basd data acquisition systms 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 carstn.nibuhr@dsy.d 13 Particl Dtctors 1 carstn.nibuhr@dsy.d 14 Particl Dtctors 1 Intraction of Radiation with Mattr Intraction of Chargd Particls Chargd Particls havy chargd particls (R -5 m) lctrons (R -3 m) [R = Rang: nrgy dpndnt indication of ordr of magnitud only] Coulomb-Intraction with lctrons of mdium Nutral Particls nutrons (R -1 m) gamma radiation (R -1 m) nutrinos (R 16 m) Mostly singular intractions, rsulting in nrgy transfr to 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: 1. inlastic collisions with shll lctrons of mdium 2. lastic scattring off nucli rlvant is th statistical sum of many such intractions. In addition thr ar th following procsss: 3. Brmsstrahlung 4. mission of Chrnkov radiation 5. nuclar ractions 6. 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 (all th rst: µ, π,p, α, light nucli) carstn.nibuhr@dsy.d 15 Particl Dtctors 1 carstn.nibuhr@dsy.d 16 Particl Dtctors 1

5 Critria for idal Dtctor Bcaus in gnral thr can b vry complx vnt topologis nd: rconstruction of full vnt kinmatics (background rjction) Cross Sction of Typical Collidr Dtctor Particl typ: - nutrinos (missing nrgy) - muons µ absorbr (mostly F) flux rturn yok havy mdium (F, Cu, U) + activ matrial Idal dtctor (partly conflicting dmands): covrag of full solid angl (4π) continuous snsitivity masur and idntify particls (trackr, calorimtr, Chrnkov dt. tc) xcllnt rsolution fast rspons, high rat capability no dad tim no aging high rliability good accssibility low cost - hadrons: p, π, K... [quarks, gluons jts] - lctrons, photons - 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 17 Particl Dtctors 1 carstn.nibuhr@dsy.d 18 Particl Dtctors 1 Exampl 1: HERA p Evnt Exampl 2: Muons p Jt 1 Jt 2 Jt 3 hadronic calorimtr lctromagn. calorimtr track dtctor transvrsal viw: Bcaus of thir larg mass (compard to lctrons) muons pass through 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 19 Particl Dtctors 1 carstn.nibuhr@dsy.d 20 Particl Dtctors 1

6 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 rathr long: Missing transvrs nrgy and transvrs momntum: i p trans 43GV carrid away by nutrino = 2 m 50 cm K + π π D 5 cm 5 mm τ O( -12 s) or cτ µm With th hlp of high prcision track dtctors on can distinguish if particls originat from scondary or primary vrtx: vrtx dtctors most frquntly basd on silicon carstn.nibuhr@dsy.d 21 Particl Dtctors 1 carstn.nibuhr@dsy.d 22 Particl Dtctors 1 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 [MV/(g/cm 2 )] Proprtis: 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 approximat rang of validity: MV/c p 50GV/c carstn.nibuhr@dsy.d 23 Particl Dtctors 1 lne at rst γ > 1 de/dx (MV g 1 cm 2 ) βγ = p/mc Muon momntum (GV/ c) Pion momntum (GV/ c) Proton momntum (GV/ c) logarithmic ris mor pronouncd for gass (H) Matrial Dpndnc H 2 liquid H gas Al F Sn Pb C Enrgy loss is a function of Z/A, I, and th dnsity ρ. Hnc us instad : 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 ) "Stopping Powr" carstn.nibuhr@dsy.d 24 Particl Dtctors H 2 gas: 4. H 2 liquid: 3.97 Solids Gass log (Z) H H Li BB CNON F Sn Z

7 de/dx Application for Dtctors de/dx for diffrnt Particl Spcis Gas ionisation proportional/drift chambr Liquid Masurmnts in PEP4/9-TPC (Ar-CH 4 = 8.5atm) µ π K p D If de/dx is plottd vrsus momntum of particl th curvs ar shiftd for diffrnt masss local hating bubbl chambr ionisation (LAr) calorimtr Solid Stat de/dx (kv/cm) Application: if also th momntum of th particl is known th masurmnt of th spcific ionisation can b usd for particl idntification xcitation of lctrons convrsion into light scintillators cration of lctron-hol pairs solid stat dtctors Momntum (GV/c) In this xampl ach dot rprsnts 185 singl masurmnts in a drift chambr carstn.nibuhr@dsy.d 25 Particl Dtctors 1 carstn.nibuhr@dsy.d 26 Particl Dtctors 1 Proprtis of som Matrials (PDG) 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) 6 1atm(K) for gas) H 2 gas (4.3) d (7300) (0.0838)[0.0899] [139.2] H 2 liquid d D (2.052) [79] [138] H (1.937) [786] [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 [183] [1.977] [4] carstn.nibuhr@dsy.d 27 Particl Dtctors 1 Th distribution of nrgy loss is in gnral not symmtric du to: rar nrgy transfrs with larg E (> ionisation potntial) which lad to δ-lctrons for lctrons: brmsstrahlung avrag nrgy loss > most probabl nrgy loss dscription by Landau distribution Landau Tail carstn.nibuhr@dsy.d 28 Particl Dtctors 1

8 Enrgy Loss of Elctrons Intraction of Photons with Mattr In addition to nrgy loss by ionisation high nrgy particls also loos nrgy du to intraction with th Coulomb fild of th nucli: Brmsstrahlung Du to thir small mass this ffct is spcially prominnt for lctrons (positrons): de dx Z 2 E it is usful to introduc radiation lngth x nrgy attnuation: E = E xp approx.: critical nrgy : approximatly: 716g cm X 2 A 0 = Z( Z + 1) ln( 287 Z) E c de Brms dx E c de = collision dx 6MV = Z Exampl: Cu E c αlne σ 1 1Mb Cross sction (barns/atom) 1kb 1 mb Cross sction (barns/atom) 1b 1 b 1 Mb σ p.. σ cohrnt 1 kb σ incoh 1 b (a) Carbon ( Z = 6) xprimntal σ tot Kohlnstoff (licht) σ p.. σ cohrnt κ N σ σ incoh nuc κ (b) Lad ( Z = 82) xprimntal σ tot Bli (schwr) κ N κ σ nuc mb V 1 kv 1 MV 1 GV 0 GV Photon Enrgy C Pb V 1kV 1MV 1GV 0GV E γ Thr ffcts ar important: Photoffct: γ + atom + atom + Z σ Ph E 3.5 Comptonffct: γ + atom γ + + atom + lne σ Compton Z E Pairproduction: γ + nucl nucl. σ Pair Z 2 für E γ» 2m c 2 carstn.nibuhr@dsy.d 29 Particl Dtctors 1 Intnsity Attnuation Intnsity attnuation: I( x) = I 0 xp( µx), N with mass absorption cofficint µ A σ = [cm -1 ] A strongly nrgy dpndnt carstn.nibuhr@dsy.d 30 Particl Dtctors 1 Photon Absorption Lngth λ 1 Dfinition of mass absorption cofficint: λ = [g cm -2 ] ( µ ρ) Z σ 5 lne Ph E 3.5 σ Compton Z σ E Pair Z 2 0 connction btwn radiation lngth and high nrgy limit for pair production: 7 σ E» 1 GV 9 --4αr 2Z A 1 = ln N A Z 1 3 I( x) = I 0 xp 7 probability for pair production aftr x travrsing on is 54%. Absorption lngth λ (g/ cm 2 ) H C Si F Sn Pb 5 6 V 0 V 1 kv kv 0 kv 1 MV MV 0 MV 1 GV GV 0 GV Photon nrgy E γ carstn.nibuhr@dsy.d 31 Particl Dtctors 1 carstn.nibuhr@dsy.d 32 Particl Dtctors 1

9 λ I λ I Hadronic Intractions For high nrgis th hadronic cross sction is σ [mb] 200 constant as function of nrgy 0 indpndnt of hadron typ Matrial dpndnc of total cross sction is givn by: σ A = σ p A Charactriz hadronic intractions by hadronic A intraction lngth λ I = [cm] N A ρ σ A in tabl: = ρ A 1 3 [g/cm 2 ] λ I, (cm) 3 λ I Z 2 1 πp πd Cntr of mass nrgy (GV) carstn.nibuhr@dsy.d 33 Particl Dtctors 1 Cross sction (mb) Cross sction (mb) π + p π + p total π + p lastic σ T pp pp σ T total lastic Cntr of mass nrgy (GV) Proprtis of som Matrials (PDG) 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) 6 1atm(K) for gas) H 2 gas (4.3) d (7300) (0.0838)[0.0899] [139.2] H 2 liquid d D (2.052) [79] [138] H (1.937) [786] [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 [183] [1.977] [4] carstn.nibuhr@dsy.d 34 Particl Dtctors 1 Multipl Scattring Scattring of chargd particls off th atoms in th mdium causs a chang of dirction: z,β 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 ln x log scal! th lss likly scattring off th atomic nucli causs larg scattring angls rsulting in a dviation from a gaussian distribution at larg angls θ xampl: p = 1 GV/c, d = 300µm Si, =9.4cm θ mrad for cm distanc this mans 80µm! carstn.nibuhr@dsy.d 35 Particl Dtctors 1