Hadronic Calorimeters Strong nuclear interaction cascade Similar to

Hadronic Calorimeters • Strong (nuclear) interaction cascade • Similar to EM shower hadronic interaction length • Energy Resolution • shower fluctuations hadronic calorimeter nearly always sampling calorimeters • Shower length R. S. Orr 2009 TRIUMF Summer Institute • leakage of energy • invisible energy loss mechanisms

Sampling Calorimeter R. S. Orr 2009 TRIUMF Summer Institute

Hadronic Lateral Shower Profile • Hadronic shower much broader than EM Fe • Mean hadronic versus MCS Fe R. S. Orr 2009 TRIUMF Summer Institute

Hadronic Shower Longitudinal Development ZEUS Uranium/Scint R. S. Orr 2009 TRIUMF Summer Institute

Lateral Scaling with Material 90% containment does not scale core scales R. S. Orr 2009 TRIUMF Summer Institute

Calorimeter Energy Resolution sampling and shower fluctuations number of samples energy deposited in a sampling step stochastic term R. S. Orr 2009 TRIUMF Summer Institute

Calorimeter Energy Resolution counting statics in sensor system e. g. # of photo-electrons in PM, ion pairs in liquid argon mean # of photo-electrons in PM per unit of incident energy this term is usually negligible shower leakage fluctuations – make calorimeter as deep as $$ allow R. S. Orr 2009 TRIUMF Summer Institute

Calorimeter Energy Resolution noise - detector or electronics - important for low level signal - liquid argon electronics - detector capacitance N channels with some intrinsic noise (energy) deposited energy behaviour increases with number of channels summed over R. S. Orr 2009 TRIUMF Summer Institute

Calorimeter Energy Resolution inter - calibration uncertainty of channels - constant in E • fractional channel to channel gain uncertainty • spatial in-homogeneity of detector energy response • dead space • temperature variation • radiation damage • all these influence spatial variation of effective energy response constant R. S. Orr 2009 TRIUMF Summer Institute

Calorimeter non-uniformity R. S. Orr 2009 TRIUMF Summer Institute

Generic Detector Layers of Detector Systems around Collision Point R. S. Orr 2009 TRIUMF Summer Institute

Semi-empirical model of hadron shower development electromagnetic part hadronic part radiation length interaction length - significant amount of material in front of calorimeter (magnet coil etc. ) R. S. Orr 2009 TRIUMF Summer Institute

More Rules of Thumb for the Hobbyist • Mixtures in sampling calorimeters • Shower maximum active + passive material • 95% Longitudinal containment • 95% Lateral containment R. S. Orr 2009 TRIUMF Summer Institute

Typical Calorimeter Resolutions • Homogeneous EM (crystal, glass) CLEO, Crystal Ball, Belle, CMS. . . • Sampling EM (Pb/Scint, Pb/LAr) CDF, ZEUS, ALEPH, ATLAS. . . • Non-compensating HAD (Fe/Scint, Fe/LAr) CDF, ATLAS, H 1, LEP = everyone • Compensating HAD (DU/Scint) ZEUS, HELIOS R. S. Orr 2009 TRIUMF Summer Institute

Invisible Energy in Hadronic Showers R. S. Orr 2009 TRIUMF Summer Institute

Difference in Response to Electrons and Hadrons R. S. Orr 2009 TRIUMF Summer Institute

Effect of e/h on Energy Resolution tail Fe/Scint DU/Scint R. S. Orr 2009 TRIUMF Summer Institute

Effect of e/h on Linearity Fe/Scint DU/Scint R. S. Orr 2009 TRIUMF Summer Institute

R. S. Orr 2009 TRIUMF Summer Institute

Weighting to Correct for e/h Energy resolution does not improve Weight down EM part of shower tune R. S. Orr 2009 TRIUMF Summer Institute

Jet Energy Resolution Jet-jet Mass Resolution Fluctuations between EM and Hadronic component in jets will degrade the energy resolution for jets Effects other than e/h dominate the 2 jet mass resoluton R. S. Orr 2009 TRIUMF Summer Institute

Jet-Jet Mass Resolutions R. S. Orr 2009 TRIUMF Summer Institute

Conceptual Readout Schemes R. S. Orr 2009 TRIUMF Summer Institute

ZEUS Forward Calorimeter R. S. Orr 2009 TRIUMF Summer Institute

R. S. Orr 2009 TRIUMF Summer Institute

Generic Detector Layers of Detector Systems around Collision Point R. S. Orr 2009 TRIUMF Summer Institute

LAr Calorimetry • Five different detector technologies • Calorimetry coverage to SM Higgs Discovery Potential EM Calorimeter WW Fusion Tag jets in Forward Cal Hadronic & Forward Calorimeters

LAr Calorimeter Technology Overview Design Goals • EM Calorimeters ( Technology ) and Presampler ( ) Lead/Copper-Kapton/Liquid Argon Accordion Structure • Hadronic Endcap ( ) Copper/Copper-Kapton/Liquid Argon Plate Structure • Forward Calorimeter ( ) Tungsten/Copper/Liquid Argon Paraxial Rod Structure

LAr and Tile Calorimeters Tile barrel Tile extended barrel LAr hadronic end-cap (HEC) LAr EM end-cap (EMEC) LAr EM barrel LAr forward calorimeter (FCAL)

Electromagnetic Barrel Module Schematic with presampler • 64 gaps /module • 2. 1 mm gap • 2 x 3100 mm long Half Barrel Assembly • 2 x 16 modules • I. R/O. R 1470/2000 mm • 22 - 33 • 3 longitudinal samples • • presampler R. S. Orr 2009 TRIUMF Summer Institute

Electromagnetic Endcap • 2 x 8 modules • Diam. 4000 mm • 22 - 37 • 3 longitudinal samples • 96 gaps /module outer wheel 32 gaps/module inner wheel • 2. 8 - 0. 9 mm gap outer 3. 1 -1. 8 mm inner • • Front sampling of 6 for , - strips. R. S. Orr 2009 TRIUMF Summer Institute

Accordion Structure Pb Absorber • Honeycomb spacer & • Cu/Kapton electrode R. S. Orr 2009 TRIUMF Summer Institute

Prototype of EM endcap Detail of Kaptons R. S. Orr 2009 TRIUMF Summer Institute

ATLAS FCAL R. S. Orr 2009 TRIUMF Summer Institute

Pictures of assembly process

LAr Forward Calorimeters • FCAL C assembly into tube – Fall 2003

Liquid Argon Gap Tungsten Rod

ATLAS HEC Structure R. S. Orr 2009 TRIUMF Summer Institute

• Transformer matching • Does not work in magnetic field. Long readout cables slow down signal • Large capacitance, large noise • EST • Works in magnetic field • Low capacitance

Hadronic Endcap Calorimeter (HEC) Front Wheel Rear Wheel Assembly Composed of 2 wheels per end Front wheel: 67 t 25 mm Cu plates Back wheel: 90 t 50 mm Cu plates

Oct 2002

Electromagnetic Endcap

Hadronic Endcap

HEC – FCAL Assembly

Test Beam Single Particle Energy Resolution Noise subtracted energy resolution

Noise Level in LAr Calorimeters Since the FCal is in the very forward region, these noise levels are OK

Signal Shape before startup

Lar Endcap Installed in ATLAS