Calorimeters/Calorimetry in Particle and Nuclear Physics

1. Calorimeters/Calorimetry in Particle and Nuclear Physics Roman Pöschl LAL Orsay ILC School on Calorimetry Beijing/China April 2009

2. Curriculum of the Lecture 1) General Introduction on Calorimeters 2) Interactions of Electrons 3) Interactions of Photons 4) Electromagnetic Showers 5) Hadronic Showers 6) Signal Generation/Response of Calorimeters 7) Readout Devices 8) Layout of Calorimeters 9) Energy, Spatial Resolution Fluctuations and all that ... 10) Calibration of Calorimeters 11) Overview of recent Calorimeters employed in experiments Appendix A: Atom in a Radiation Field - The Photoeletric Effect

3. Calorimeters Chapter 1 - XVIII Heidelberger Graduiertentage Literature used for the Lecture R. Wigmans: Calorimetry D. Wegener: Detektoren in der Teilchenphysik - Lecture Uni Dortmund W.R. Leo: Techniques for Nuclear and Particle Phyisics Experiment C. Grupen: Teilchendetektoren Sitar et al.: Ionization measuremens in High Energy Physics + Lots of Material ‘stolen’ from presentations,articles found in the Web. If you find that I have used your material without a citation please write me and I will include the reference Thanks to Hengne Li from LAL for producing several figures for this lecture

4. Chapter 1 General Introduction on Calorimeters

5. Fachhochschule Flensburg - Institut für Physik  Heat Calorimetric techniques do have their origin in thermodynamics - Evaporation heat of a liquid - Specific heat of a substance - Heating of environment by radioactive substances

6. Typical Scales in Thermodynamics and (Sub-)Atomic Physics Unit in Thermodynamics: 1 J/1 Calorie It takes 1 Calorie (=4.18 Joule) to heat up 1g of water from 14.5 oC to 15.5 oC Unit in (Sub-)Atomic Physics: 1 eV = 1.6 10-19 J (Nowadays) Typical Energies in Nuclear and Particle Physics: 106 – 1012 eV = MeV - TeV Even the highest energetic particles would deposit only ~ 10-12 J in a given quantity of Water (Need lots of water to absorb such a particle, see later) High Energetic Particle DT » 0 Thermodynamic methods are not suited for our purposes !!!! Macroscopic observables O(1023) particles involved What else ???

7. How to detect the presence of a small particle??? ... and there was light!!! (Charged) Particles create (visible) light when passing through material Ionization (Here) Excitation (more important) Light is emitted when excited atoms fall back into ground state Amount of light ~ Energy of primary particle Ion beam passing through air Adapt measurement technique to microscopic size of particles to be detected Light creation is a quantum, i.e. microscopic phenomenon

8. + What kind of particles do we want to measure ? De-excitation of a Nucleus: Detect radiated photon Nucleus A Photon Nucleus A* High energetic collision in Particle Physics Experiment Plethora of particles in final state: Subject to a)electromagnetic interaction g, e b) strong interaction charged neutral h Calorimeters

9. V(r) V0 ~ (ma2)-1»40 MeV for m=mproton and a=1 fm = 5 GeV-1 r a -V0 Energy Range to be covered by Calorimetric Measurements 60Co Decay Spectrum with two prominent lines at 1.1 and 1.3 MeV Nuclear Decays: Energy range gouverned by typical nuclear potential (e.g. Schwabl, p.299) KeV Scattered Electron in Deep Inelastic ep Reaction Probing the Proton Structure Proton Radius 5 GeV-1 DRDQ » 1 Need O(10-100) GeV for deep insight into the proton

10. Energy Range to be covered by Calorimetric Measurements – cnt'd Smashing particles – High energetic final state in Collider Experiments Energy of final state particles only limited by power of accelerator Higgs Production in e+e- Collisions at the ILC Several hundreds of GeV Energy deposition Expect O(TeV) at the LHC

11. Dimensions of Calorimeters ATLAS TileCal Barrel Calorimeter 4p 'Germanium Ball' of AGATA Experiment 1m ~10m Calorimeters are employed in 'table top' experiments and in huge experimental apparatuus