MICE EmCal

Overview of Design and Construction Technique

Hardware and Software activities

Ludovico TortoraINFN - Roma III

CERN - 29 March 2003

NIM A 482 (2002) 363-385

Density ≈ 5 g/cm3

Sampling fraction for mip ≈ 15%Radiation length ≈ 1.5 cm

The construction technique consists in embedding 1 mm diameterpolystyrene based blue scintillating fibers between thin grooved lead plates,obtained by plastic deformation of 0.5 mm thick lead foil.

Fibers are glued to the lead plates and run parallel to each other with apitch of 1.35 mm and are mostly orthogonal to the entering particles.

Fine Grained Calorimeter Option for Electron Identifier

The Construction Technique of KLOE EmCal

fiber

T.O.F. IIIT.O.F. IIIPrecise timingPrecise timing

Electron IDElectron IDEliminate muons that decEliminate muons that dec

Tracking devices: Tracking devices: He filled TPC-GEM (similar to TSLA R&D)He filled TPC-GEM (similar to TSLA R&D)and/or and/or scisci-fi-fiMeasurement of momentum, angles and positionMeasurement of momentum, angles and position

T.O.F. I & IIT.O.F. I & IIPion Pion /muon ID/muon IDprecise timingprecise timing

10% cooling of 200 MeV muons requires ~ 20 MV of RF single particle measurements => measurement precision can be as good as ∆ ( ε out/ε in ) = 10-3

201 MHz RF cavities

Liquid H2 absorbersor LiH ?

SC Solenoids;Spectrometer, focus pair, compensation coil

muons defocused by fringe field

and

EmCal

…omissis … we decided in Chicago in February 02 that : the useful spectrometer field region should be 100 cm long and 30 cm diameter the inner bore should be 40 cm

KLOE Construction Techniques

• Pb sheet swaging machine (large & small)• Precision growing of layers• Scintillating fibers• Optical epoxy• Pressure application• Accurate machining of module• Winston cones & light guides

Small Swaging Machine @Regina

Zisis PapandreouDept. of Physics

University of Regina

Zisis PapandreouDept. of Physics

University of Regina

Big Swaging Machine @ LNF

The grooving rollers result by theassembling of 13 disk-like pieces,50 mm thick and 400 mm in diametermade of hardened steel and ground toshape by a sintered diamond tool;the rollers are fixed by means of ballbearings on a very rigid frame and arealigned and checked with a set ofmicrometers.

The achievable thickness uniformity isaround few tens of µm and the groovescan deviate from a straight line by lessthan 0.1 mm per foil length.

The AMS option for a “KLOE_like” Electromagnetic Calorimeter

• www.pi.infn.it• The Electromagnetic Calorimeter is built of layers of 1.5 mm lead and 1 mm scint. fibers.• The granularity for readout is 2x2 cm2 (about 1 radiation lenght x 1 rad.l.).• In this way is possible to study the longitudinal and the lateral shape of the e. m. showers.• The cell length is 65 cm and the readout of this system is only on one side.• To have the information about the coordinate along the fiber, each superlayer has fibers

oriented perpendicularly to the next.

Scintillating Fibers

• Kuraray (SCSF-81 type) 1 mm fibers• PolHiTech (0046 or 0044 type) 1 mm fibers• Both emit in blue-green region• Have 3-4 m attenuation length and 2.5 ns decay

constants• Kuraray are sensitive to UV light

Optical Fiber Tests with 100MeV pions

• Properties:– Light collection efficiency

(cladding)– Scintillation light production

(doping)– Light attenuation

coefficient– Timing resolution

• Fibers Types (single-,double-clad)– Kuraray SCSF-81– Pol.Hi.Tech. 0046– Bicron (too expensive) M11 Experimental Area at TRIUMF

August 2001

Zisis PapandreouDept. of Physics

University of Regina

Zisis PapandreouDept. of Physics

University of Regina

Spectrum and Attenuation Length

Optical Epoxy

• UHU industrial epoxy to glue to Al plate• Bicron-600 optical glue

– 28:100 hardener to epoxy– Curing time 1.5-2.5 hrs– Application: Glue-fibers-glue; teflon clamps– Requires proper training, suites, masks, gloves,

ventillated and dust-free room…• Pressure application (pistons or vacuum)• 150 µm Al tape; care to avoid delamination

Pisa Pistons – Front and Side Views

Prototype Module Construction

96 x 13 x 10 cm3

70 kg

B. Klein, J. Kushniryk,T.Summers, G. WilliamsLead Sheet Swaging

Matrix gluing & pressing

Inspection and cleaning

Prototype Pb/SciFi Modules

Build in May 2002with help from

KLOE Folks

KLOE Winston cone light guide

[cell dimension : 3,5×3,5×200 cm3]

How visible energy looks like

LADON Test @ LNF - 1993 Test @ PSI - 1994

electronsphotons

The KLOE experienceshows that the visible energy isa linear function of the kineticenergy of the electrons in therange 20 ÷ 300 MeV.

Defining 1 MIP as thevisible energy deposited by aminimum ionizing particle in aread out element, the slope is≈ 37 MIP/GeV

Linearity

4%

1 %

Electrons 00 ≤ θ ≤ 400

MIP and Muons in KLOE

Energy response for muons

Pµ (MeV/c) 150 200 240 280

Energy response for muons and pions[cell dimension : 3,5×3,5×200 cm3]

P= 200 MeV/c P = 250 MeV/c

∑∑=

i i

i ii

EEX

X distribution for 3.5 cm granularity

NIM A 354 (1995) 352-363

Electrons and Muons impacting the Calorimeter

by P. Janot

The momentum distribution (upper plot) and the directionality distribution(lower plot) of the electrons (histogram) and muons (shaded histogram).

The angle θ is the angle between the particle momentum and the z axis

Electrons and Muons in MICE

KLOE-like Electron Identifier is characterized by :

- Radiation length ≈ 1.5 cm - Density ≈ 5 g/cm3

- Moliere radius ≈ 3 cm

From P. Janot simulation :

Muons (150 ÷ 350) MeV/c quite collimated (0 ÷ 0.2 ) rad Electrons ( 0 ÷ 300 ) MeV broad angular spread ( 0 ÷ 1.2 ) rad

With a EmCal depth 12÷15 cm (8÷10 X0) :

Muons (mostly) punching through for Pµ > 200 MeV/c ( tagged by a “ aligned sequence of MIP signals ” )

Enough containment for electron showers (300 MeV electrons have the maximun of shower ≈ 3.5 cm after conversion point and are tagged by cluster of cells)

eIt’s possible to distinguish electronsfrom muons by means of :

⇒ path reconstruction based

on the energy released inside

the calorimeter’s elements

⇒ combination of cluster length, total energy, energy per plane …

Pattern of visible energy

KLOE EmCal : NIM A 482 (2002) 363-385[cell dimension : 4,4×4,4×400 cm3]

15.000 Km of fibres (Kurarary & Pol. Hi. Tech) Average attenuation length ≈ 400 cm

Number of PhotoElectrons NPE = (AMIP × GADC) / GPM - Cosmic Ray ⇒ 35 PE/MIP - exp. energy scale ⇒ 40 MeV /MIP (obtained from showering particles of known energy like Bhabha at φ peak…)

Light yield ≈ 1 PE/MeV deposit at 200 cm far from PM

KLOE is operating with hardware electronics threshold ≈ 4mV corresponding to ≈ 3 MeV energy deposit at calorimeter center

As Electron Identifier for MICE ( length ≈ 60 cm ) we estimate to collect 70÷90 photoelectrons per MIP

hardware threshold ≤ 2 MeV

Energy and Timing Resolutions

• In KLOE the EmCal is made of 5000 elements, most of them 4 meterlong and 4.3x4.3 cm2 of section, we find :- energy resolution

- timing resolution• In MICE these features have to be taken into account as reference for

possible contributions to :⇒ the system of time of flight⇒ the trigger⇒ impact point reconstruction (≈ 2 cm)

• As Electron Identifier in a MICEwe expect (even) better resolutions(because we collect more photoelectrons per MIP)

)(%7.5 GeVE

)(54 GeVEpsNIM A 482 (2002) 363-385

Conclusions

•A possible design for the MICE Electron Identifier is a calorimeter (60x60 cm2 , 12÷15 cm thick) made of lead-scintillating fibers composite built as described above.

•A first evaluation suggests a read out granularity of 3.75x3.75 cm2

- to have a very high efficiency (≥ 99%) in electron tagging over all the energy range- a µ misidentification factor ≈ 10-3

•The proposed segmentation requires, in case of double side read out, to manage 128 electronics channels.

STEP I: we get the muon beam

In this first phase we define the beam tunings, composition,settings for both mu+ and mu- as a function of momentum.

needed:beam (!)

TOF,trigger

some DAQtwo SCI FI arrays or beam chambers

PID

10 m

EmCal Module and PMs Readout

… resuming KLOE EmCal prototype @ Roma III ….

cut-out of KLOE EmCalPrototype 0 (LNF twin)

≈ 200 lead/scintillating fiberslayers corresponding to ≈ 15 X0

12 cells 44 × 44 mm2 each

light collected by a gluedWinston cone guide

only one side readout byHamamatsu R1398

Schematic view of the 14-cells

KLOE Calorimeter prototype 0

230 mm ≈ 15 X0

132

mm

≈ 8

X0

470 m

m

44 × 44 mm2

LNFbeam

Low energy electrons

… some background ….

Energy range

≈ 75 % ≈ 16 %

≈ 5%≈ 2%

Longitudinal and Transverse Shower Profile

ROWS1 2 3 4

COLUMNS

2

ETOT (MIPs)

BEAM

Shower transverse profile (Calorimeter 1)

e+e- → Φ→ KS KL with KS→ π0π0 and KL→ πeνγ

.. some K± KLOE events...

e+e- → Φ → K+ K-

K- → π-π0 , K+ → µ+ν

e+e- → Φ → K+ K-

K+ → µ ν , K- → π0 e ν

+

-

K-

+

Muons from charged Kaons decay in KLOE

(Alessandra Tonazzo)

Muons from charged Kaons decay in KLOE

(Alessandra Tonazzo)

… KLOE published data on KS semileptonic decays ….

π−

e+

ν

ΚL

e+e- → Φ → KL KS

KL crash , KS → π e ν

MX (e+e−→x+x-γ)

π+π−γ

π+π−π0

e+e−γ

before likelihood

after likelihood

µ+µ−γ

…. from KLOE analysis of e+e-→π+π-γ events ….

(selection by ToF + EmCal likelihood) backgrounds : e+e- → µ+µ- γ , e+e- → e+e-γ

(Anna Ferrari)

Sample of Electrons and Muons

(Anna Ferrari)

electrons

muons

Energy deposition per layer

Electrons Muons

Eplan (1) Eplan (2)

Eplan (3) Eplan (4)

( Anna Ferrari )

Barycentre of the visible energy

Electrons

Muons

∑∑=

i i

i ii

EEX

X

Electron and Muon identification

XCUT = 8.5 cm

% IN OUT

µ 99.87 0.13e 0.85 99.15

electrons

muons

( Anna Ferrari )

∑∑=

i i

i ii

EEX

X

X

Electron and Muon identification

XCUT = 8.0 cm

% IN OUT

µ 100.00 0.00e 1.4 98.6

electrons

muons

( Anna Ferrari )

∑∑=

i i

i ii

EEX

X

X

EmCal : homogeneity of response and µ/e identification

The EmCal structure is intrinsically homogenous; so his response doesn’tdepend on kinematic parameters of impinging particles (except for thresholdeffect on the energy deposition).High efficiency in detection is guaranteed if enough active material is fired,that is the EmCal has adequate transversal dimensions which allow fullsampling, even for strongly divergent particles.As far µ/e identification concerns, the ”KLOE-like” EmCal shows a tagefficiency greater than 99%. To reach 1 0/00 of misidentification, the simplevisible energy measurement is not enough; some pattern recognition - alreadyexperimented in KLOE - has to be implemented to distinguish electrons fromstopping muons. Therefore we need adequate readout granularity.“ the tail of the high energy muon spectrum could generate some light in theCerenkov and be counted as an electron” ; (apparently) no problem for EmCalthanks to the peculiar and very clean pattern shape of a minimum ionizingparticle.

Info on MICE EmCal

Construction schedule : 1 year for a detector 60x60x15 cm3

but :pending technical decision about final layout and dimensions, major involvement of LNF infrastructures and external firms have to be consideredSpending profile :ready to place 90% of ordersneeded to do asap (procurements will take lot time) but pending financial approval

Work going on and planes

- recovery of equipments & tools

- “prototype” test @BTF

- look at KLOE data analysis for MICE goals(reproducibility of simulations)

e/µ simulations in spaghetti

e/µ simulations in tiles

…. downstream Cerenkov…. … KLOE calorimeter ……