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Technology Choices for the sPHENIX Calorimeter Systems. C.Woody For the PHENIX Collaboration. CALOR12 Santa Fe, NM June 5, 2012. 4.65 m. 70 cm. 9 5 cm. 210 cm. Detector R equirements that Determine Technology Choices. Detector Requirements
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Technology Choices for the sPHENIX Calorimeter Systems C.Woody For the PHENIX Collaboration CALOR12 Santa Fe, NM June 5, 2012
4.65 m 70 cm 95 cm 210 cm C.Woody, CALOR12, 6/5/12
Detector Requirements that Determine Technology Choices • Detector Requirements • Large solid angle coverage (± 1.1 in h, 2p in f) • Moderate energy resolution • EMCAL ~ 15%/√E • HCAL ~ 50-100 %/√E (single particle) • Compact (for EMCAL small RM, short X0) • Hermetic • Projective (approximately) • Readout works in a magnetic field • Low cost • Technology Choices: • EMCAL → Tungsten Scintillating Fiber Accordion • HCAL → Iron Scintillating Tile with WLS Fiber • Readout → SiPMs C.Woody, CALOR12, 6/5/12
Optical Accordion Accordion design similar to ATLAS Liquid Argon Calorimeter Layered accordion of tungsten plates and scintillating fibers • Volume increases with radius • Scintillator thickness doesn’t increase with • radius, so either tungsten thickness must • increase or the amplitude of the oscillation • must increase, or both • Plate thickness cannot be totally uniform • due to the undulations • Small amplitude oscillations minimize both • of these problems Want to be projective in both r-fand h C.Woody, CALOR12, 6/5/12
Sintered Tungsten Plates Variable thickness W-plates Scintillating fibers in between Density r ~ 17.5 g/cm3 Problem is that cannot make sintered plates larger than ~ 20 cm Phase I SBIR with C.Woody, CALOR12, 6/5/12
Tungsten-SciFi Epoxy Sandwich Uniform thickness, thin pure tungsten metal sheets with wedge shaped SciFi + tungsten powder epoxy layer in between Can be made into larger modules (> 1m) Fabricate in industry 2 W plates/layer 0.6 X0 sampling Pure tungsten metal sheet (r ~ 19.3 g/cm3) Thickness: 2x1.0 mm Tungsten powder epoxy (r ~ 10-11 g/cm3) 0.08-0.2 mm Scintillating fibers 1.0 mm X0 = 5.3 mm RM = 15.4 mm C.Woody, CALOR12, 6/5/12
Effect of Glue on Light Yield • Gluing fibers reduces light output due to loss of cladding light • Depends on glue • Does not seem to depend on whether glue contains tungsten powder or not 100 p.e./MeV Direct fiber readout on PMT With a sampling fraction of 4% and 100 p.e./MeV in scintillator 4000 p.e./GeVin the calorimeter C.Woody, CALOR12, 6/5/12
Light Yield and Readout Devices Want to have small photostatistics contribution to the energy resolution Need sufficient light output from fibers to allow randomizing and collecting the light onto a small readout device Possible Readout Schemes Small reflecting cavity or wavelength shifting block SiPM Scintillating Fibers 21 mm 21 mm Need to match ~126 1 mm diameter fibers onto a 3x3 mm2 SiPM with good efficiency and uniformity (earea ~ 2%) C.Woody, CALOR12, 6/5/12
Module Construction Tungsten-SciFi “sandwiches” are cast together in 6 layers to form a module ~ 2 cm “tower” in r-f, ~ 9.5 cm depth, ~ 1.4 m long (L/2) Modules assembled in groups of 4 to form sectors (~ 400 lb each) 64 sectors arranged azimuthally to cover 2p (x2 for both sides) C.Woody, CALOR12, 6/5/12
Hadron Calorimeter 60 cm 3.5 labs 30 cm 1.5 labs 4 inner and 4 outer plates joined together to form one section • Steel plates with scintillating tiles parallel to beam direction • Tapered steel plates sampling fraction changes with depth • Divided into two longitudinal sections • Measure longitudinal center of gravity correct for longitudinal fluctuations • Plates tilted ± 5o in opposite directions to avoid channeling • Iron in steel serves as flux return C.Woody, CALOR12, 6/5/12
HCAL Readout Similar to T2K: Scintillating tiles with WLS fibers embedded in serpentine grooves (Scint:extruded polystyrene made in Russia, WLS:Kuraray Y11) Fibers embedded in grooves on both sides of tile Expect ~ 12 p.e./MIP/tile (T2K) ~ 400 p.e./GeV in HCAL T 2x11 scintillator tile shapes 8 readout fibers per tower Outer readout SiPMs + mixers 2x11 segments in h (Dh =0.1) 64 segments in f (Df=0.1) 1408 x 2(inner,outer) = 2816 towers Inner readout (~10x10 cm2) Outer Inner C.Woody, CALOR12, 6/5/12
Testing HCAL Scintillator Components University of Colorado BNL Groved tiles Mixer and SiPM readout Russia Extruded scintillator with WLS readout C.Woody, CALOR12, 6/5/12
SiPM Readout Common readout for both EMCAL and HCAL EMCAL segmentation ~ .025 x .025 (h x f) ~ 25K channels HCAL segmentation ~ 0.1 x 0.1 ~ 3K channels Considering various devices: Hamamatsu, AdvanSiD, Zecotek,… Also considering APDs 3x3 mm2,14.4K pixels (25 mm) G ~ 2 x 105, peak PDE ~ 25% @ 440 nm S10362-33-25C • Want dynamic range ~ few x 103 • 10 MeV – 20 GeV per tower • Due to saturation, must tune light levels to give ~5 – 10,000 p.e. • Avoid noise a 1 p.e. level • Requires temperature compensation • and control • dVbr/dT ~50 mV/°C dG/dT ~ 10% /°C Zecotek MAPD-3N 3x3 mm2, 135K pixels C.Woody, CALOR12, 6/5/12
Readout Electronics Large signals don’t need ultra low noise electronics Can use a conventional voltage/current amplifier Dynamic range essentially determined by SiPM ORNL VBAdj SiPM preamp with differential output Readout will use either a derivative of an existing PHENIX ADC system from the Hadron Blind Detector or the CERN SRS system interfaced through the Beetle chip SiPM preamp impulse response (SPICE) C.Woody, CALOR12, 6/5/12
Summary • The upgrade from PHENIX to sPHENIX will require the design and construction of two new major calorimeter systems: • W-SciFi Optical Accordion EMCAL • Iron Scintillating Tile WLS Fiber HCAL • Both will implement new technologies made possible through the development of new materials, photodetectors and construction techniques. • Both calorimeters will build on existing and proven designs, but will also incorporate several newand novel designs features that need to be thoroughly understood and tested. • We feel we have a good, sound basic design concept, but we have a lot of work to do to insure that these detectors will work as we hope. C.Woody, CALOR12, 6/5/12
Backup Slides C.Woody, CALOR12, 6/5/12
HCAL Outer HCAL Inner EMCAL Solenoid VTX C.Woody, CALOR12, 6/5/12
EMCAL Energy Resolution GEANT4 Simulation • Accordion Layers: • Tungsten metal: 2x1 mm • Scintillating fiber: 1 mm • Tungsten-epoxy: 0.08 – 0.20 mm sE/E ~ 14%/√E Sampling frequency: 0.6 X0 Sampling fraction: 4.2% Total layers: 30 Total depth: 17.4 X0 Total thickness: 9.5 cm C.Woody, CALOR12, 6/5/12
Single Particle Energy Resolution No CoG weighting No CoG or E/H weighting C.Woody, CALOR12, 6/5/12
Total Calorimeter Jet Resolution Single jet resolution in p+p collisions Central Au+Au events (HIJING) w/o detector resolution but including underlying events PYTHIA + Full GEANT4 simulation Recon: FastJet anti-kT, R=0.2 PYTHIA + FastJet + jet energy smearing C.Woody, CALOR12, 6/5/12
Origin of the Optical Accordion E. Kistenev and colleagues from IHEP circa ~2005 Pb+ Scintillator Plate + WLS Fiber C.Woody, CALOR12, 6/5/12