Calorimeters for the linear collider detector

1. I. A. Savin 80 Calorimeters for the linear collider detector Introduction CALICE collaboration Calorimeter test beam results Summary Jaroslav Cvach, Institute of Physics ASCR, Prague

2. 1. Introduction • I.A. Savin and Prague physics: • 1964-70 πp scattering • 1969-79 BIS • 1977-92 NA4 • 1988-90 tagged ν at UNK • 1992 Compass • NA4 experiment: • Important school for experimentalists from • Institute of Physics ASCR • Faculty of Mathematics and Physics, CU • J. Žáček, J. Cvach, J. Strachota, P. Reimer, S. Němeček, J. Hladký, R. Lednický, P. Závada From nucleon structure functions to calorimeters • NA4 (BCDMS) – mainly data analysis • 1986  H1 at HERA – read-out electrodes for LAr calorimeters (ECAL, HCAL) • Slow control • Spacal electronics • Data analysis • 2001  Calorimeters for ILC • Scintillator tile hadron (electronics, data analysis) • SiWelmg. (Si pad sensors) JC, I.A.Savin, 80

3. 2. CalorimetryforLCs • CALICE Collaboration – worldwide calorimeter R&D effort • EUDET – European grant under 6th FP, I3 (2006-10) AIDA – European grant under 7th FP, INFRA (2011-14) • Electromagnetic Calorimeter with W absorber • Silicon pads 1 x 1 cm2 0.5 x 0.5 cm2 • Scintillator strips 1 x 4 x 0.35 cm3 with MPPC readout • Hadron Calorimeter with steel (W) absorber • Scintillator tiles with analogue readout • RPC / Micromegas / GEM – with digital readout • Muon Tail Catcher – steel absorber and scintillator strips • Coordinated test beam programme to combine different technologies at the same time and prove Particle flow paradigm JC, I.A.Savin, 80

4. Particle Flow paradigm •  Reconstruct every particle in the event • up to ~100 GeV - tracker is superior to calorimeter  • use tracker to reconstruct e±,m±,h± (<65%> of Ejet ) • use ECAL for greconstruction (<25%>) • (ECAL+) HCALforh0 reconstruction (<10%>) • HCAL E resolution still dominates Ejet resolution • But much improved resolution (only 10% of Ejet in HCAL) PFLOW calorimetry =Highly granular detectors(CALICE) + Sophisticated reconstruction software

5. Jet energy resolution Partons are reconstructed as Jets q̄ q Jet Energy Resolution s/Ejet (%) ALEPH measured CDF measured ATLAS simulation H1 measured DREAM measured ILC goal PFA simulation Jet Energy (GeV)

6. The technology tree Calorimeter ZOO      JC, I.A.Savin, 80

7. CALICE Test Beam Program Muon trigger 17648 read-out channels • Data recorded: • 2006 – DESY, 2006-7 - CERN • 2008-9 – Fermilab • Si-W and Scint-Fe ECAL, AHCAL, TCMT • e± 1-50 GeV, ±, ±2 - 80 GeV • Various impact points & angles of incidence 0°, 20°, 30°, 45° • Envisaged tests: • 2010-11 – Fermilab, Digital HCAL • 2010-11 – CERN, AHCAL with W absorber + 1 plane with Micromegas JC, I.A.Savin, 80

8. Silicon-Tungsten ECAL • Absorber • 30 layers of W: 1.4, (0.4 X0), 2.8 and 4.2mm thick • 24 X0 in total • Active Element • 30 layers of Si diode pads • 1cm2, 525 µm thickness • 6480 channels • ~ ½ sensorsfromCzechRep. – Praguemaincontribution • Read-out by ASIC • Large dynamic range • Auto-trigger on ½ MIP • On chip zero suppress • Ultra-low power « 25µW/ch • In beam 2006 - 8 JC, I.A.Savin, 80

9. Si-W ECAL, results Measured linearity and resolution of energy as response to electrons Detector performs as expected from simulations nonlinearity<1% Longitudinal shower profiles Energy resolution = 16.5%/sqrt(E)+1.1% JC, I.A.Savin, 80

10. Analogue HCAL • Absorber • 38 layers of steel, 2 cm thick • 4.5 λint in total • Active element • Scintillator tiles 3x3 – 12x12 cm2 with embedded WLS fibres • Multi-pixel Geiger mode photo-diodes (SiPM, MPPC), B-field proof, small, affordable, integrated • Read-out by ASIC • 2 gains (normal, calibration) • HV settings for SiPMs • Shaping and multiplexing • Power consumption 200 mW/5 V • Calibration and monitoring by LED flashes, temperature rec. • In beam 2006-9 JC, I.A.Savin, 80

11. Calibration and monitoring systemPrague main contribution Functionalities of the LED system: 1) gain calibration at low intensity light 2) provide reference pulses monitored by PIN diodes 3) provide full dynamic range for checking the SiPM response function Temperature monitored by temperature sensors ∆G/G ∆ T ~ -1.7%/K

12. SiPM response to low LED light 1 LED illuminates 18 SiPM

13. 3. Energy reconstruction by software compensation Cluster finding in HCAL to determine properties of the shower (global) (total energy, volume, longitudinal structure … ) Used as input to neural net, training with the MC simulation Non-weighted distribution - larger response at higher energies. Sw compensation – linearity back to ~ 2% Resolution improved by ~ 25 % JC, I.A.Savin, 80

14. Physics lists in Geant 4.9.3 (2009) outdated – Geant 3 • Composition of the Geant4 physics lists for pions • All physics lists combine at least two models • The high granularity of the calorimeter allows detailed studies of the substructure of hadron showers in the energy range 10 – 80 GeV prefered by LHC test beam data open to CALICE test beam data JC, I.A.Savin, 80

15. Less short tracks in models, E< 20 GeV (E = 25 GeV) JC, I.A.Savin, 80

16. JC, I.A.Savin, 80

17. 1 m3 – Digital Hadron Calorimeter Physics Prototype Description Readout of 1 x 1 cm2 pads with one threshold (1-bit) →Digital Calorimeter 40 layers each ~ 1 x 1 m2 Each layer with 3 RPCs, each 32 x 96 cm2 ~350,000 readout channels Layers to be inserted into the existing CALICE Analog (scintillator) HCAL structure Purpose Validate DHCAL concept Gain experience running large RPC systems Measure hadronic showers in great detail Validate hadronic shower models Status Construction in 2008 – 09 Tests 2010 - 11 Square meter plane with readout boards JC, I.A.Savin, 80

18. 1 m3 calorimeterin beam „Several years of work by a group led by Argonne Physicist Jose Repond (HEP) are paying off, as the Digital Hadron Calorimeter at the International Linear Collider produces incredible detail of hadron showers. For the first time, researchers can measure individual particles in a hadronic jet.“ Argonne today, November 4, 2010 π+ shower

19. HCAL 1.5m ECAL Si-W sandwich 29 layers Each active layer equipped with readout electronics  Power pulsing Extreme integration Next challenge: ‣ Demonstrate feasibility and scalability of imaging calorimeters with fully integrated electronics in a real collider detector ‣ Meet the space constraints in a real collider detector ‣ Minimize amount of cables leaving the detector/cracks = Maximize hermeticity Design of a multi-layers barrel ECAL and HCAL JC, I.A.Savin, 80

20. 4. Summary • Testing the new calorimeter concept • Operation of a 8000 channel system with a novel photodetector SiPM successful • Calibration established • Systematic established • AHCAL prototype – a new tool for hadron shower physics • Methods developed to identify the first hadron interaction • Methods developed to estimate and correct longitudinal leakage • Several simulation models compared to test beam data • SS absorber replaced by W – new data are coming now • WHCAL π beam tests November 2010, January-February 2011 • Main task – time development of hadronic shower from W JC, I.A.Savin, 80