Calorimetry: a new design

2004/Sep/15K. Kawagoe / Kobe-U

Introduction

• Our previous studies– Pb/Scinti optimized for compensation– ~45%/sqrt(E) resolution for single hadrons– ~15%/sqrt(E) resolution for electrons/photons– Fine granularity ECAL (strip-array & small tile)

• New design– To be optimized for Particle Flow Algorithm (PFA) aimin

g at 30%/sqrt(E) resolution for jets– ECAL: W/Scinti with SiPM analog readout– HCAL: Pb(Fe)/Scinti with SiPM (semi-)digital readout– Other options ?

Typical “Huge” models under consideration

SiVTX pixel (cold version)

HCAL(Pb(Fe)/scinti or digital)

W/Scinti ECAL

TPC(Jet chamber as option)

Si intermedi.-Trk

SC-coil

SiVTX pixel

Pb/scinti HCAL

Pb/Scinti ECAL

Jet chamber

Si intermedi.-Trk

SC-coil

“GLC” design (ACFA) “Huge” (world-wide)

• Area of EM CAL (Barrel + Endcap)– SD: ~40 m2 / layer– TESLA: ~80 m2 / layer– Huge: ~100 m2 / layer– (GLC: ~130 m2 /layer)

Huge

~2.1m

Comparison of size of EM CAL surface

Layout of scintillators• We have an experience of strip-array ECAL.• Array of 1cmx20cmx2mm-thick strips• Advantages :

– Fine granularity (1cmx1cm effective cell size)– Reasonable cost– No WLS fiber bending

• Disadvantages :– Ghost rejection needed

New: Strip & Tile CAL

• We have an experience of small tile ECAL, too.

• Ghost clusters would be easily removed with additional small-tile layers.

• This idea SHOULD be well confirmed by full simulation studies.

• Strip & Tile CAL can be achieved with SiPM readout (directly attached to WLS fibers) .

Common layout for ECAL and HCAL

ECAL structure

• An ECAL super-layer consists of– W 3mm + X-strips 2mm +cable 1mm– W 3mm + Y-strips 2mm +cable 1mm– W 3mm + small tiles 2mm + cable 1mm

• Effective Moliere radius 18mm• 10 super-layers (30 layers)

– Total thickness 18cm (r=210-228cm).– Total radiation length ~26X0.

• Dimensions (to be optimized)– Strips (1cm x 20cm)– Small tiles (4cm x 4cm)

HCAL structure

• An HCAL super-layer consists of– Pb 20mm + X-strips 5mm +cable 1mm– Pb 20mm + Y-strips 5mm +cable 1mm– Pb 20mm + small tiles 5mm + cable 1mm

• Pb is good for compensation, but may be replaced by Fe.

• Is this sampling fine enough ? (need simulation)• 15 super-layers (45 layers)

– Total thickness 117cm (r=230-347cm).– Total Pb thickness 90cm ~ 5.3I.– Add ECAL (1.0I) 6.3I (thick enough?)

• Dimensions (to be optimized for PFA)– Strips (1cm x 20cm)– Small tiles (4cm x 4cm)

Number of readout channels

• With 20cm x 1cm strips and 4cm x 4cm tiles

• ECAL prototype– 650 analog readout channels

• Calorimetry for the real detector– ECAL: ~2.0M analog readout channels.– HCAL: ~5.5M (semi-)digital readout channels– A big challenge !!

• Number of channels could easily change the order depending on the strip/tile size.

SiPM next talk by T. Takeshita• Micro-APD cells in Geiger-mode.• Developed in Russia.• Good for fiber readout

– Gain~106 (No amplifier needed)– ~1000 pixels in small area (~1mm x 1mm)

• Further R&D is needed for– Better quantum efficiency (now: ~20%)– Lower noise rate (now: ~1MHz)– Larger effective area (now: ~1mm2) for other applications

• CALICE Analog HCAL will use ~8000 Russian SiPMs.• Hamamatsu started to develop a similar device.

W plates

• Contact with a Japanese company (A.L.M.T. corp.)– W alloy is easier to handle than pure W.– W:Ni:Cu=95:3.4:1.6, density=18g/cm3, no magnetism.

• For ECAL prototype– We need 30 W plates (20cm x 20cm x 3mm-t) .– Rough cost estimate ~1.5MYen (or ~25Yen/g).

• For real ECAL detector– We need ~200ton W plates.– Mass production may reduce the cost: ~10Yen/g.– Very rough cost estimate ~ 2 BYen.– Production in 3 years is possible.

R&D issues

• Design optimization (scintillator shape and size)– to remove “ghost” clusters– to match tracks and clustersfor particle flow algorithm

• Photo-sensors (SiPM)• Readout electronics• Gain monitoring system • Mechanical structure

Possible schedule (very very preliminary)

• 2004-2005 – Design optimization– R&D of SiPM (DPPD)– R&D of readout electronics

• 2005-2006– Construction of an ECAL test module– Tests with cosmic-rays

• 2006-2008– Test beam studies of the ECAL test module

“standalone”– Test beam studies in combination with CALICE

HCAL

Institutes/staffs• Japan

– KEK (J. Kanzaki)– Kobe U. (K. Kawagoe)– Konan U. (F. Kajino)– Niigata U. (H. Miyata)– Shinshu U. (T. Takeshita)– Tsukuba U. (S. Kim, H. Matsunaga)

• Korea– Kyungpook National U. (D. Kim)

• Russia– Joint Institute for Nuclear Research (D. Mzhavia, P. Evtukhovitch,

et al.) • Good relation with CALICE, especially with Analog HCAL gr

oup at DESY (V. Kobel et al.).

Conclusions

• New calorimeter design– ECAL W+Scinti+SiPM, analog readout– HCAL Pb(Fe)+Scinti+SiPM, (semi-)digital readout

• R&D issues– Design optimization– SiPM– Readout electronics– Gain monitoring– Mechanical structure

• Schedule– Test beam for ECAL prototype in 2006 ?

• Of course, any other ideas / activities are welcome !!