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

2. Manuel I. Martin Friday, April 2, 2004Manuel I. Martin 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.

3. Manuel I. Martin Friday, April 2, 2004Manuel I. Martin 3 Further Comments Hadron Calorimeter Design Our Preferred Solution Finely segmented Analog HCFinely 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 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 electronics as well as cables 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.

4. Manuel I. Martin Friday, April 2, 2004Manuel I. Martin 4 DHC Proof OF PRINCIPLE Digital vs. Analog Both hits and energy have the same distributions in the calorimeters, plausible to expect energy-based and hit-based resolutions to be similar Hits ECALE ECAL Hits HCALE HCAL 10,50 GeV  EM.25cm 2 HC 9cm 2 Tile Sizes

5. Manuel I. Martin Friday, April 2, 2004Manuel 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. For lower energy particles the digital approach has excellent resolution! Single Particle Energy Resolution

6. Manuel I. Martin Friday, April 2, 2004Manuel I. Martin 6 DHC Proof OF PRINCIPLE Determine resolution independent of algorithm For ZZ events P T order stable MC particles, ignore ’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  ~ 17%/sqrt(E) Start with highest p T 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 ! Jets

7. Manuel I. Martin Friday, April 2, 2004Manuel I. Martin 7 Energy (Particle) Flow Algorithms 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. Jet E rec /E gen Digital (2x2) Analog

8. Manuel I. Martin Friday, April 2, 2004Manuel I. Martin 8 Digital Hadron Calorimeter Design Hardware Prototypes: Stack, Layer, & Unit Cell MAPTM

9. Manuel I. Martin Friday, April 2, 2004Manuel I. Martin 9 Digital Hadron Calorimeter Design Cosmic Data with PMT Readout CELLS Cast, Hexagonal, 9.4cm 2, TREATMENT Acrylic Paint, Sigma Groove WLSF Bicron PMT Hamamatsu 16 ch. SIGNAL ~13 p.e. peak = 1MIP* ABSORBER ~1”/Layer Brass

10. Manuel I. Martin Friday, April 2, 2004Manuel I. Martin 10 Digital Hadron Calorimeter Design 0.25 MIP threshold: efficient, quiet Uniformity within Cell ~ 3% Cell-to-Cell Dispersion ~7% Dispersion is dominated by the fiber treatment. Cell boundaries

11. Manuel I. Martin Friday, April 2, 2004Manuel 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.

12. Manuel I. Martin Friday, April 2, 2004Manuel 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.

13. Manuel I. Martin Friday, April 2, 2004Manuel 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.

14. Manuel I. Martin Friday, April 2, 2004Manuel I. Martin 14 A first look at structure support Support structure: we know how to build it! 2mm GAP Absorber Scintillating Tile WLSF 1Cylinder of Tungsten 29 Cylinders of Brass All made of identical interlocking bars and two “end collars” also made of interlocking parts Bar Cross- section Bar length 6m Mechanical Engineering School of Northern Illinois University Brass Cylinder Max Deflection:.023149 mm

15. Manuel I. Martin Friday, April 2, 2004Manuel I. Martin 15 Scintillator DHC Conclusions 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) 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) 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.

16. Manuel I. Martin Friday, April 2, 2004Manuel 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.

17. Manuel I. Martin Friday, April 2, 2004Manuel I. Martin 17 TestBeamMokka Based on Mokka v02-03 Currently maintained at NICADD Actively working with Mokka development team Available for community use

18. Manuel I. Martin Friday, April 2, 2004Manuel I. Martin 18 Tail-catcher Test beam event display neutrals charged EMEM HCHC TC/TC/ Goals for the TC/Muon System 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

19. Manuel I. Martin Friday, April 2, 2004Manuel I. Martin 19 Tail-catcher Why is it needed ? How to implement it ? 20GeV p  Tail-catcher/Muon System NICADD proposes to use the Muon System as Tail-Catcher Tracker 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.

20. Manuel I. Martin Friday, April 2, 2004Manuel I. Martin 20 Tail-catcher Erec/Egen 50 GeV p 

21. Manuel I. Martin Friday, April 2, 2004Manuel 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!