5 November 2004CBM-Russia meeting Proposal for IHEP participation in CBM ECAL Yuri Kharlov Institute for High Energy Physics Protvino

5 November 2004 CBM-Russia meeting

Proposal for IHEP participation in CBM ECAL

Yuri KharlovInstitute for High Energy Physics

Protvino


Outline

• Scintillator sampling calorimeters manufactured in IHEP

• IHEP plastic scintillator facility• Simulations and data analysis


Scintillator calorimeters• IHEP has a long history of electromagnetic and hadron

calorimetry contributed to many of HEP-experiments.• Different types of e.m. calorimeters were manufactured in

IHEP:– Cherenkov calorimeters (lead glass)– Scintillator sampling calorimeters– Scintillating crystal calorimeters (PbWO4)

• Scintillator sampling calorimeters:– 1985: invention of the molding technology– 1988: first “shashlyk” R&D with INR– 1992: PHENIX ECAL (BNL, RHIC)– 1993-1995: HERA-B ECAL (DESY, with ITEP)– 1994: DELPHI STIC (CERN, LEP)– 2000: COMPAS HCAL (CERN, SpS)– 2001: ATLAS HCAL (CERN, LHC)– 2004: LHCb HCAL (CERN, LHC)– 2000-200?: KOPIO (BNL, AGS)


E.M. calorimeter in PHENIX

R&D: 1994

Typical sampling lead-scintillator calorimeter of 15,552 channels

66 sampling layers

E/E=8% at 1 GeV

Time resolution = 100 ps

36 fibers of WLS-doped polysterene penetrate the modules

Modules are assembled into 6x6-array supermodules

PHENIX Tech. Note 236, 06/96


E.M. calorimeter STIC in DEPLHI

NIM A 425 (1999) 106

Small angle Tile Calorimeter for luminosity monitoring

47 Pb(3mm)-Sci(3mm) layers

2 Si strip detectors inserted after 7 and 13 sampling layers to measure shower development

1600 WLS fibers (0.79 fiber/cm2)

E/E=3% at 45 GeV

=1.5

r=0.3-1 mm


E.M. calorimeter in KOPIO

Contributions to the energy resolution:Contributions to the energy resolution:

To achieve the energy resolution of 3%E(GeV) the sampling, photo-statistics and light collection uniformity have to be improvedTest beam results and the simulation Test beam results and the simulation

model is described in model is described in NIM A 531 (2004) 476NIM A 531 (2004) 476

First prototype for KOPIO (First prototype for KOPIO (INR, TroitskINR, Troitsk):):240 240 (0.35 mm lead + 1.5 mm scint.) (0.35 mm lead + 1.5 mm scint.)Energy resolution 4%E(GeV). (for 1 GeV/c positron)

E865E923

KOPIO prototype

Economy: adequate performance for ~1/10 cost of crystals


KOPIO: 3%/ELateral segmentation 110110 mm2

Scintillator thickness 1.5 mm

Gap between scintillator tiles 0.300 mm

Lead absorber thickness 0.275 mm

Number of the absorber layers (Lead / Scint) 300

WLS fibers per module 72 1.6 m = 115 m

Fiber spacing 9.3 mm

Holes diameter in Scintillator / Lead 1.3 mm / 1.4 mm

Diameter of WLS fiber (Y11-200MS) 1.0 mm

Fiber bundle diameter 14.0 mm

External wrapping (TYVEK paper) 150

Effective Xo 34.0 mm

Effective RM 59.8 mm

Effective density 2.75 g/cm3

Active depth 540 mm (15.9 Xo)

Total depth (without Photodetector) 650 mm

Total weight 18.0 kG

CALOR 2004, Perugia, Italy, March 29-April 2, 2004


KOPIO: Calorimeter moduleKOPIO: Calorimeter moduleThe design innovations:•New scintillator tile (BASF143E + 1.8%pTP + 0.04%POPOP produced by IHEP) with improved optical transparency and improved surface quality. The light yield is now ~ 60 photons per 1 MeV of incident photon energy. Nonuniformity of light response across the module is <2.3% for a point-like light source, and < 0.5% if averaged over the photon shower.. •New mechanical design of a module has four special "LEGO type" locks for scintillator’s tiles. These locks fix the position of the scintillator tiles with the 300-m gaps, providing a sufficient room for the 275 m lead tiles without optical contact between lead and scintillator. The new mechanical structure permits removing of 600 paper tiles between scintillator and lead, reduces the diameter of fiber’s hole to 1.3 mm, and removes the compressing steel tape. The effective radiation length X0 was decreased from 3.9 cm to 3.4 cm. The hole/crack and other insensitive areas were reduced from 2.5 % up to 1.6 %. The module’s mechanical properties such as dimensional tolerances and constructive stiffness were significantly improved.•New photodetector Avalanche Photo Diode (630-70-74-510 produced by Advanced Photonix Inc.) with high quantum efficiency (~93%), good photo cathode uniformity (nonuniformity 3%) and good short- and long-term stability. A typical APD gain is 200, an excess noise factor is ~ 2.4. The effective light yield of a module became ~24 photoelectrons per 1 MeV of the incident photon energy resulting in negligible photo statistic contribution to the energy resolution of the calorimeter.


KOPIO: light yield in scintillatorScintillator: PS+Fluor1+Fluor2,

Manufacturer

Light yield

(% of Anthracene)

Attenuation

Length (cm)

Light yield of MIP,

p.e. per tile

Simulated light collection efficiency

PSM115+1.5%pTP+0.04%POPOP,

TECHNOPLAST, 1998

53 6 4.0 0.3 4.4 0.3,

100%

0.134 0.013,

100%

BASF158K+1.5%pTP+0.04%POPOP,

IHEP, 2001

56 6 4.9 0.4 5.6 0.3,

(127 10)%

0.170 0.017,

(127 13)%

BASF165H+1.5%pTP+0.04%POPOP,

IHEP, 2001

56 6 6.1 0.5 6.4 0.3

(145 10)%

0.191 0.019,

(143 14)%

BASF143E+1.5%pTP+0.04%POPOP,

IHEP, 2002

54 6 6.8 0.5 7.1 0.3,

(161 10)%

0.215 0.021,

(160 16)%

Light yield variation over tile’s samples


KOPIO: light collection in the tile

Tile (face view)


KOPIO: energy resolution

Energy resolution for 220-370 MeV photons:

(GeV)/)%05.074.2()%1.096.1(/

(GeV)/)%05.079.2()%1.098.1(/

(GeV)/)%05.006.3()%1.003.2(/

WFDAPD

QDCAPD

PMT

EE

EE

EE


KOPIO: time resolution

Time difference in two modules was measured


KOPIO: photon detection inefficiency

Simple estimate of Inefficiency (due to holes):

Effect of holes is negligible if incident angle > 5 mrad


Calorimeter readout

•Readout systems (photo-multipliers and high-voltage system) were provided by IHEP for PHENIX (16 000 channels), HERA-B (6000 channels); LHCb (6500 ECAL+1800 HCAL channels);

•IHEP together with MELZ is working on modernization of the photo-multipliers PMT115M with low rate effect. First prototypes with stability 1% at I=20A were produced.


Plastic scintillator facility in IHEPhttp://www1.ihep.su/ihep/ihepsc/index.html

The research and development program of plastic scintillators started in IHEP morethan 20 years ago. The works were concentreted in the following directions:1. the production of polysterene scintillators using the process of styrene

polymerization in blocks;2. the extrusion of bulk-polymerized scintillators from blocks;3. the production of molded scintillators by the injection molded technique.

Scintillators manufactured be methods 1 and 2 were tested and used in domestic experiments at IHEP as well as some experiments abroad

With the help of method 3, large volumes of scintillators for several experiments in IHEP (~3 tons) and for hadron calorimeters Hcal1 and Hcal2 of experiment in COMPASS (~2 tons) were manufactured.

During the last decade the demand on molded scintillators for various projects (PHENIX, HERA-B, ATLAS, LHC-b) have inceased up to several tens of tons per year.

Production time scale: 15 tons of scintillators (>750,000 plates) for KOPIO could be manufactures in 1.5 years.


Plastic scintillator facility in IHEP

Injected mold scintillator production facility

Injected mold machime in automatic processing of the tiles.

3x3 module for KOPIO

Plates for KOPIO


ECAL simulations and data analysis

IHEP group has experience in e.m. calorimeters simulations and data analysis, particularly in heavy-ion experiments (PHENIX, STAR, ALICE) which should be similar to CBM in complexity.

•Calibration

•Shower shape measurements

•Shower reconstruction

•Particle identification (photons, electrons, hadrons)

•Physics analysis


ECAL calibration

Before calibration After calibration

Calibration by wide electron beam with minimization of the mean quadratic deviation


Shower shape measurement(PbWO4 calorimeter)


Particle identification

PID in ECAL based on:

•Shower shape

•TOF

•Charge track matching

Good identification of photons, electrons, charged and neutral hadrons, (anti)nucleons.

GEANT3 simulation for PHOS, ALICE

e-

- anti-n


0 spectrum and background subtraction (Pb-Pb at 5.5 ATeV)


IHEP contribution to CBM ECAL• Participating together with other member institutes in

– Defining physics motivation for ECAL in CBM;– Conceptual desing of ECAL;– R&D:

• Detailed simulation to optimize ECAL parameters;• Beam-tests of the prototypes in IHEP and GSI;

– ECAL readout (PMT+HV system);– Monitoring system;– Data analysis;

• Full responsibility for manufacturing of the ECAL modules (Pb-Sci sampling).

Documents

5 November 2004CBM-Russia meeting Proposal for IHEP participation in CBM ECAL Yuri Kharlov Institute for High Energy Physics Protvino