NA62, 21 October 2010V.Polyakov, Shashlik calorimeter1 Radiation hard Shashlik calorimeter for COMPASS experiment Vladimir Polyakov Institute for High

NA62, 21 October 2010 V.Polyakov, Shashlik calorimeter

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Radiation hard Shashlik calorimeter for COMPASS

experiment

Vladimir Polyakov Institute for High Energy Physics, Protvino


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Outline

1. The COMPASS experiment

2. Requirement and motivation

3. Design of spiral Shashlik module

4. MC and beam test results of the

Shashlik prototype

5. Mass production of Shashlik

modules

6. Conclusion


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The COMPASS experimentCommon Muon Proton Apparatus for Structure and

Spectroscopy

2nd spectrometer

1st spectrometer

SM1 magnet

SM2 magnet

50 m

ECAL1

ECAL2

First electromagnetic calorimeter• dimension: 4.0 x 2.9 m2,; 1500 channels, • three types of lead glass blocks 38x38 mm2, 75x75 mm2, 142x142 mm2;• central hole 1.1x0.6 m2;• angular acceptance 180x130 mrad

Second electromagnetic calorimeter(GAMS-4000 detector, since 1980 at

CERN, NA12 and WA102)

• dimension: 2.6 x 2.0 m2,; 3000 channels;• Spiral Shashlik and lead glass blocks, 38x38 mm2;

Muon beam: data taking 2002-2007 Intensity 2x108 spill-1

Hadron beam: data taking 2008-2009 Intensity 5x107 spill-1


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Limitation for ECAL2: Radiation dose

350 days running, 190 GeV hadrons, 5x107/spill, maximal dose – 40 krad

ECAL2 before 2008

Total number of channels – 3068, 38.2x38.2mm lead glass blocks ~800 radhard blocks

Radiation thickness – ~16 X0

Radiation hardness – 400 rad for lead glass blocks 3 krad for radhard lead glass blocks

Energy resolution – 6%/√(E) 2% for lead glass blocks 6%/√(E) 4% for radhard lead glass blocks

Minimal angle – 0mradMaximal angle – 40mrad (horiz.) and 30mrad ( vert.)


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350 days running, hadron beam 190 GeV, 5.0107/spill

Rad

4000

400

40

Need additional 900 rad hard blocks

2 krad

400rad


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Radiation hardness 500 krad

Energy range 1÷190 GeV

Energy resolution

Radiation thickness 23 X0

Uniformity 1÷2% for angular range 0-40mrad

Module size 38.2x38.2 mm2

Module length 450 mm

COMPASS requirements for radhard calorimeter:

%5.0E

%5.5

1. PWO crystals – very high price, radiation instability for low dose;

2. Shashlik calorimeter – bad energy resolution and uniformity for small angles (up to 50mrad)


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ZEUS Shashlik EM-calorimeter;NIM A: 450 (2000) no. 2-3, pp.235-252.

~25% ~15%

e±, p,n


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Spiral Shashlik module

Dimensions 38.2x38.2 mm2

Radiation length 17.5mm Moliere radius 36mm Radiation thickness 22.5 X0

Scintillator thickness 1.5mm Lead thickness 0.8mm Radiation hardness 0.5 Mrad Energy resolution 6.5%/√E 1%

Calo meeting, 26 October 2010 V.Polyakov, Shashlik beam tests

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Spiral Shashlik

1mm

1.4mm

2mm

22.50

Sampling – 0.8 mm lead and 1.5 mm scintillator; 4x4 fibers, 4 steel rods; 155 layers

4 types of scintillators and 2 types of lead plates


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ECAL2, Run 2003 1000 blocks remove780 radiation hard blocks installECAL2, Run 2008, 6448 GAMS lead glass blocks, 22 blocks central hole

864 Shashlik modules

768 radhard GAMS blocks

GAMS blocks

GAMS blocks

1440 GAMS blocks


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ECAL2, Run 2003 1000 blocks remove780 radiation hard blocks install3 types of modules that are used in ECAL2 calorimeter

Shashlik modules

radhard GAMS lead

glass blocks

GAMS lead glass blocks


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Energy resolution (T9 and H4 beam tests)

σE/E = a/√E b c/E

σE/E = a/√E b


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Uniformity, 4GeV electrons


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Uniformity, 70GeV electrons


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Profile for 10 GeV photons

RM = 36 mm

TB, February 2011 VP, Shashlik 16

∏0 from real data; Shashlik shows 30% better resolution compared to lead glass


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Mass production

Radiation hardness of scintillators was measured up to 250 krad

Loading test No changes in light yield and attenuation after 4 month of loading

with 120 kg

Online control: The spread of light yield for scintillators is less than 3% The spread of the thickness of lead is less than 80μk ( 10%) Measurements of light yield and attenuation length for each spiral

Shashlik modules Attenuation length > 1.7m Light yield > 400 photoelectrons per MIP

Production speed – 200 modules per month


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IHEP Scintillator Fasilitieswww.ihep.ru/scint/index-e.htm


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Mould

Scintillators


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Scintillators


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Conclusion

The new type of the Shashlik calorimeter were design and developed;

900 spiral Shashlik modules for upgrade of second electromagnetic calorimeter of COMPASS experiment are produced;

Spiral Shashlik calorimeter is adequate the requirements of COMPASS;

Documents

NA62, 21 October 2010V.Polyakov, Shashlik calorimeter1 Radiation hard Shashlik calorimeter for COMPASS experiment Vladimir Polyakov Institute for High