Toward a scintillator-based Digital Hadron Calorimeter and Tail-catcher for the LC

1. Toward a scintillator-based Digital Hadron Calorimeter and Tail-catcher for the LC XI International Conference on Calorimetry in High Energy Physics Perugia, Italy, March 29 – April 2, 2004 Manuel I. Martin Northern Illinois University NICADD formed 2001 employees 25 people

2. Goals for a Hadron Calorimeter Design • To design a hadron calorimeter with jet resolution better than a conventional caloriemter at reduced cost. • The HC must be: • Finely Segmented for shower separation inside jets • Hermetic • Reliable • Capable of working in a 5 Tesla magnetic field • Inexpensive Detector under investigation: A finely segmented hadron calorimeter optimized for Energy Flow Algorithms and cost.   Both performance and cost are driven by the degree of segmentation and the number of thresholds (1,2,3..)  and we have studied both with simulations and prototypes.    Although we have done a great deal of R&D only a few highlights will be presented today. Manuel I. Martin

3. Further Comments Hadron Calorimeter Design Finely segmented Analog HC Finely segmented Digital HC • PROS • Well understood response • High Dynamic Range • ‘Direct’ measure of Energy • CONS • High segmentation implies high cost • Probably segmentation limited to 5x5 cm sections • Cost dominated by electronics • PROS • Very low cost of electronics • Can reach very fine segmentation • Ideal for shower resolution • CONS • Required extensive research to show proof of principle • Will require development of new algorithms • Will need fine tuning Our Preferred Solution Trading dynamic range for finer segmentation allows one to see the shower structure inside a jet. The HC acquires tracking capabilities. The Energy Flow algorithm translates into a Particle Flow algorithm. The cost of extra channels is offset by the lower cost of front end electronicsas well ascables and infra-structure for the electronics. The Digital HC can have a dynamic range of 2 bits maintaining all the advantages mentioned and improving the relationship between Energy deposit and the number of hits above 3 different thresholds. Manuel I. Martin

4. DHC Proof OF PRINCIPLE Digital vs. Analog Hits ECAL E ECAL EM .25cm2 Tile Sizes HC 9cm2 10,50 GeV p Hits HCAL E HCAL Both hits and energy have the same distributions in the calorimeters, plausible to expect energy-based and hit-based resolutions to be similar Manuel I. Martin

5. DHC Proof OF PRINCIPLE Single Particles Number of Cells vs. Pion Energy For a 0.25 MIP threshold, the # of hits increases monotonically with energy for a wide range of cell sizes. Single Particle Energy Resolution For lower energy particles the digital approach has excellent resolution! Manuel I. Martin

6. DHC Proof OF PRINCIPLE Jets • Determine resolution independent of algorithm • For ZZ events PT order stable MC particles, ignore n’s • For charged hadrons assume perfect energy (from tracker) • Smear the energy of other particles • For neutral hadrons use resolutions for charged pions presented in the previous slide. • For photons use s ~ 17%/sqrt(E) • Start with highest pT particle and cluster in 0.7 cone • Repeat for remaining particles • Add individual energies to get jet energy Toy Simulation: “Recipe” for a Jet So the idea holds water: At all energies 3x3 single threshold resolution comparable to analog! Manuel I. Martin

7. Energy (Particle) Flow Algorithms Jet Erec/Egen Energy Flow algorithms offer the most promising way, to date, of achieving the unprecedented jet energy resolutions required to fully exploit the physics program of a Linear Collider Detector (LCD). NICADD has been pursuing the development of algorithms suitable to use in a DHC and preliminary results show compatible performance to those used in analog HC. Although not shown the inclusion of additional thresholds to compensate for cell saturation also improves response. We have dubbed this a “semi-digital” approach. Digital (2x2) Analog Manuel I. Martin

8. Digital Hadron Calorimeter Design Hardware Prototypes: Stack, Layer, & Unit Cell MAPTM Manuel I. Martin

9. Digital Hadron Calorimeter Design Cosmic Data with PMT Readout • CELLS • Cast, Hexagonal, 9.4cm2, • TREATMENT • Acrylic Paint, Sigma Groove • WLSF • Bicron • PMT • Hamamatsu 16 ch. • SIGNAL • ~13 p.e. peak = 1MIP* • ABSORBER • ~1”/Layer Brass Manuel I. Martin

10. Digital Hadron Calorimeter Design Uniformity within Cell ~ 3% Cell-to-Cell Dispersion ~7% Dispersion is dominated by the fiber treatment. Cell boundaries 0.25 MIP threshold: efficient, quiet Manuel I. Martin

11. Our Extrusion Facility at FNL NICADD owns a double screw extruder intended to develop inexpensive extruded scintillator bars of different shapes and characteristics. The extruder is maintained and run by NICADD in collaboration with FNAL and is a resource for the scientific community. Manuel I. Martin

12. Put table of light yields here         *  Extruded material is a low cost, viable alternative to cast material        *  The ALICE experiment has determined this as well for their EMCAL. Manuel I. Martin

13. Digital Hadron Calorimeter Design PHOTO_DETECTORS Representative Spectra Si-PMs (PULSAR/MEPHI) mounted on cell Metallic Resistive Silicon (CPTA)        * Measurements made at NICADD       *  Devices perform similarly PMTs - a viable solution       *Fibers internal to tiles will ease manufacturing/assembly/cost. Manuel I. Martin

14. A first look at structure support Support structure: we know how to build it! WLSF Bar Cross-section Bar length 6m 2mmGAP Brass Cylinder Max Deflection: .023149 mm Absorber Scintillating Tile • Cylinder of Tungsten • 29 Cylinders of Brass • All made of identical interlocking bars and two “end collars” also made of interlocking parts Mechanical Engineering School of Northern Illinois University Manuel I. Martin

15. Scintillator DHC Conclusions Simulations indicated that the approach taken is competitive with an analog HC. Measurements with our prototypes indicate that we have enough sensitivity and linearity. Although time did not allow presentation, the semi-digital (use of more than one threshold) permits a linearization of the E/Tiles Hit up to ~50GeV. SiPM and MRS are very promising. Preliminary prototypes and structure studies show we can control costs. USING • Hexagonal or Square Cells 4 - 9 cm2 • Straight Groove • High yield fiber • Glued Fiber and Painted Surface • Extruded (cut costs) @ 5mm • Custom Charge Amplifier/Discriminator All-in-all it looks like a competitive option…. We’ll be moving towards the next prototype tower (and a test beam DHC and Tail Catcher) Manuel I. Martin

16. Test Beam Efforts • NICADD is collaborating with CALICE & DESY to study the DHC at a test beam • Contributing hardware and personnel • Primary goal is to study segmentation and response. • We are also constructing a combined hadronic tail catcher/muon tracking. Manuel I. Martin

17. TestBeamMokka • Based on Mokka v02-03 • Currently maintained at NICADD • Actively working with Mokka development team • Available for community use Manuel I. Martin

18. Tail-catcher Test beam event display Goals for the TC/Muon System charged • Provide a reasonable snapshot of the tail-end of the shower for simulation validation • Prototype detector with high-fidelity to what is imagined for a generic LCD • correcting for leakage • understanding the impact of coil • muon reconstruction + e-flow • reduce fake rate of muons EM charged TC/ HC neutrals Manuel I. Martin

19. Tail-catcher/Muon System Tail-catcher Why is it needed ? How to implement it ? 20GeV p A.Raspereza • Details are important! • Due to physical restrictions the HC for the proposed LC is very thin! • Leakage is inevitable. • We must recover as much information as possible. NICADD proposes to use the Muon System as Tail-Catcher Tracker Manuel I. Martin

20. Tail-catcher Erec/Egen 50 GeV p Manuel I. Martin

21. Conclusions • Calorimetry • DHC Simulations indicate approach competitive with analog calorimetry • DHC Prototypes indicate there is sufficient sensitivity (light x efficiency), uniformity, and costs can be controlled • Tail-Catcher/Muon tracker design/prototype underway • Simulations • Supports design/prototype work • Support of TB and event generation (not mentioned) for community • Test Beam • Looking forward to collaboration with CALICE/DESY to study prototypes! Manuel I. Martin