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

2. Outline Scintillator sampling calorimeters manufactured in IHEP
IHEP plastic scintillator facility
Simulations and data analysis
5 November 2004
CBM-Russia meeting

3. 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)
: 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)
?: KOPIO (BNL, AGS)
5 November 2004
CBM-Russia meeting

4. E.M. calorimeter in PHENIX
PHENIX Tech. Note 236, 06/96
R&D: 1994
Typical sampling lead-scintillator calorimeter of 15,552 channels
66 sampling layers
DE/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
5 November 2004
CBM-Russia meeting

5. 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)
DE/E=3% at 45 GeV
Df=1.5
Dr=0.3-1 mm
5 November 2004
CBM-Russia meeting

6. E.M. calorimeter in KOPIO
First prototype for KOPIO (INR, Troitsk):
240  (0.35 mm lead mm scint.)
Energy resolution 4%E(GeV).
(for 1 GeV/c positron)
Contributions to the energy resolution:
E865
E923
KOPIO prototype
To achieve the energy resolution of 3%E(GeV) the sampling, photo-statistics and light collection uniformity have to be improved
Test beam results and the simulation model is described in
NIM A 531 (2004) 476
Economy: adequate performance for ~1/10 cost of crystals
5 November 2004
CBM-Russia meeting

7. KOPIO: 3%/E CALOR 2004, Perugia, Italy, March 29-April 2, 2004
Lateral segmentation
110110 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
5 November 2004
CBM-Russia meeting

8. KOPIO: Calorimeter module
The design innovations:
New scintillator tile (BASF143E + 1.8%pTP %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 ( 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.
5 November 2004
CBM-Russia meeting

9. KOPIO: light yield in scintillator
Scintillator: PS+Fluor1+Fluor2,
Manufacturer
Light yield
(% of Anthracene)
Attenuation
Length (cm)
Light yield of MIP,
p.e. per tile
Simulated light collection efficiency
PSM %pTP+0.04%POPOP,
TECHNOPLAST, 1998
53  6
4.0  0.3
4.4  0.3,
100%
0.134  0.013,
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,
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
5 November 2004
CBM-Russia meeting

10. KOPIO: light collection in the tile
Tile (face view)
5 November 2004
CBM-Russia meeting

11. KOPIO: energy resolution
Energy resolution for MeV photons:
5 November 2004
CBM-Russia meeting

12. KOPIO: time resolution
Time difference in two modules was measured
5 November 2004
CBM-Russia meeting

13. KOPIO: photon detection inefficiency
Simple estimate of Inefficiency (due to holes):
Effect of holes is negligible if incident angle > 5 mrad
5 November 2004
CBM-Russia meeting

14. Calorimeter readout
Readout systems (photo-multipliers and high-voltage system) were provided by IHEP for PHENIX ( 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=20mA were produced.
5 November 2004
CBM-Russia meeting

15. Plastic scintillator facility in IHEP http://www1. ihep
The research and development program of plastic  scintillators started in IHEP more than 20 years ago. The works were concentreted in the following directions:
the production of polysterene scintillators using the process of styrene polymerization in blocks;
the extrusion of bulk-polymerized scintillators from blocks;
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.
5 November 2004
CBM-Russia meeting

16. Plastic scintillator facility in IHEP
Plastic scintillator facility in IHEP
Injected mold machime in automatic processing of the tiles.
Injected mold scintillator production facility
3x3 module for KOPIO
Plates for KOPIO
5 November 2004
CBM-Russia meeting

17. 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
5 November 2004
CBM-Russia meeting

18. ECAL calibration Before calibration After calibration
Calibration by wide electron beam with minimization of the mean quadratic deviation
Before calibration
After calibration
5 November 2004
CBM-Russia meeting

19. Shower shape measurement (PbWO4 calorimeter)
5 November 2004
CBM-Russia meeting

20. 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- p-
anti-n
5 November 2004
CBM-Russia meeting

21. p0 spectrum and background subtraction (Pb-Pb at 5.5 ATeV)
5 November 2004
CBM-Russia meeting

22. 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).
5 November 2004
CBM-Russia meeting