CALICECALICE

Toward a scintillator-based Digital Hadron Calorimeter and Tail-catcher

for the LC

Toward a scintillator-based Digital Hadron Calorimeter and Tail-catcher

for the LC

Manuel I. MartinNorthern Illinois University

XI International Conference on Calorimetry in High Energy Physics

Perugia, Italy, March 29 – April 2, 2004

NICADD formed 2001 employees 25 people

Manuel I. Martin

Friday, April 2, 2004

Manuel I. Martin

2Goals for a Hadron Calorimeter DesignGoals 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

Friday, April 2, 2004

Manuel I. Martin

3Further Comments Hadron Calorimeter DesignFurther Comments Hadron Calorimeter Design

Our Preferred Solution

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

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.

Manuel I. Martin

Friday, April 2, 2004

Manuel I. Martin

4DHC Proof OF PRINCIPLEDHC Proof OF PRINCIPLEDigital vs. AnalogDigital 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 ECAL E ECAL

Hits HCAL E HCAL

10,50 GeV

EM .25cm2

HC 9cm2Tile Sizes

Manuel I. Martin

Friday, April 2, 2004

Manuel I. Martin

5DHC Proof OF PRINCIPLEDHC Proof OF PRINCIPLE

0

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Incident Energy (GeV)

Nu

mb

er o

f C

ells

Ab

ove

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resh

old

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4cm^2

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16cm^2

2cm^2

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! 0

0.05

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s/E

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2cm^2 Digital

4cm^2 Digital

6cm^2 Digital

9cm^2 Digital

12cm^2 Digital

16cm^2 Digital

Analog

Single Particle Energy Resolution

Manuel I. Martin

Friday, April 2, 2004

Manuel I. Martin

6DHC Proof OF PRINCIPLEDHC Proof OF PRINCIPLE

• Determine resolution independent of algorithm

• For ZZ events PT 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 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!

Jets

Manuel I. Martin

Friday, April 2, 2004

Manuel I. Martin

7Energy (Particle) Flow AlgorithmsEnergy (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 Erec/Egen

Digital (2x2) Analog

Manuel I. Martin

Friday, April 2, 2004

Manuel I. Martin

8Digital Hadron Calorimeter DesignDigital Hadron Calorimeter DesignHardware Prototypes: Stack, Hardware Prototypes: Stack, Layer, & Unit CellLayer, & Unit CellHardware Prototypes: Stack, Hardware Prototypes: Stack, Layer, & Unit CellLayer, & Unit Cell

MAPTM

Manuel I. Martin

Friday, April 2, 2004

Manuel I. Martin

9Digital Hadron Calorimeter DesignDigital Hadron Calorimeter DesignCosmic Data with PMT Readout

•CELLS Cast, Hexagonal, 9.4cm2, TREATMENTAcrylic Paint, Sigma Groove•WLSF Bicron•PMT Hamamatsu 16 ch.•SIGNAL~13 p.e. peak = 1MIP*•ABSORBER~1”/Layer Brass

Manuel I. Martin

Friday, April 2, 2004

Manuel I. Martin

10Digital Hadron Calorimeter DesignDigital Hadron Calorimeter Design

Efficiency and Noise Rejection

0%

20%

40%

60%

80%

100%

120%

Number of MIPs

Pe

rce

nt

Efficiency

Noise Rejection

0

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1

1.2

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POSITION OF Sr-90, MM

NO

MA

LIZE

D R

ESPO

NSE

0.25 MIP threshold: efficient, quiet

Uniformity within Cell ~ 3%

Cell-to-Cell Dispersion ~7%

Dispersion is dominated by the fiber treatment.

Cell boundaries

Manuel I. Martin

Friday, April 2, 2004

Manuel I. Martin

11Our Extrusion Facility at FNLOur 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

Friday, April 2, 2004

Manuel I. Martin

12Put table of light yields herePut 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

Friday, April 2, 2004

Manuel I. Martin

13Digital Hadron Calorimeter DesignDigital Hadron Calorimeter Design

LED signal

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1 33 65 97 129

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ADC counts

Eve

nts

PHOTO_DETECTORS Representative Spectra

Ru106, Si-PMT, 51 Volts, ~6 PE

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1 56 111 166 221 276 331 386 441 496 551 606 661 716 771 826 881 936A D C C HA N N EL

MEPHI sample, Courtesy of B.Dolgoshein

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

Friday, April 2, 2004

Manuel I. Martin

14A first look at structure supportA first look at structure supportSupport structure: we know how to build it!

2mmGAP

Absorber Scintillating Tile

WLSF

1 Cylinder of Tungsten

29 Cylinders of Brass

All made of identical interlocking bars and two “end collars” also made of interlocking parts

Bar Cross-sectionBar length 6m

Mechanical Engineering School of Northern Illinois University

Brass CylinderMax Deflection: .023149 mm

Manuel I. Martin

Friday, April 2, 2004

Manuel I. Martin

15Scintillator DHC ConclusionsScintillator 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….All-in-all it looks like a competitive option….We’ll be moving towards the next prototype towerWe’ll be moving towards the next prototype tower

(and a test beam DHC and Tail Catcher)(and a test beam DHC and Tail Catcher)

All-in-all it looks like a competitive option….All-in-all it looks like a competitive option….We’ll be moving towards the next prototype towerWe’ll be moving towards the next prototype tower

(and a test beam DHC and Tail Catcher)(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.

Manuel I. Martin

Friday, April 2, 2004

Manuel I. Martin

16Test Beam EffortsTest 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

Friday, April 2, 2004

Manuel I. Martin

17TestBeamMokkaTestBeamMokka• Based on Mokka v02-03• Currently maintained at

NICADD• Actively working with

Mokka development team

• Available for community use

Manuel I. Martin

Friday, April 2, 2004

Manuel I. Martin

18Tail-catcherTail-catcher

Test beam event display

neutrals

charged

charged

EM

HC

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

Manuel I. Martin

Friday, April 2, 2004

Manuel I. Martin

19Tail-catcherTail-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.

Manuel I. Martin

Friday, April 2, 2004

Manuel I. Martin

20Tail-catcherTail-catcher

Erec/Egen 50 GeV p

Manuel I. Martin

Friday, April 2, 2004

Manuel I. Martin

21ConclusionsConclusions• 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!