Transcript No Slide Title

ALCPG Calorimetry:
Hardware Aspects of ECAL and HCAL Options
• ECAL R/D
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–
–
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Si-W
Scintillator-W
Hybrids
crystals
• HCAL R/D
– Scintillator
– RPC
– GEM
Acknowledgement: these slides from Jose Repond, David Strom, Graham Wilson
Mark Oreglia, ACFA-6, December 2003
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US R&D Context
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•
Growing number participating in LC related R&D -- funding improving
Calorimetry – regular phone/video meetings every other week with
emphasis on
– ECAL, HCAL and simulation
– http://www.slac.stanford.edu/xorg/lcd/calorimeter/
• No “baseline” detector concept, rather 2 main concepts :
– Large detector – large R (1.9m) , gaseous (TPC) tracking, B=3T
– SD (Silicon detector) – smaller R (1.25m), B=6T, silicon tracker
• ECAL design should be compatible with either X-band or TESLA
• The ECAL R&D is investigating several approaches.
– Cross-fertilization from different perspectives
• Some convergence
– Opportunities for strengthening international collaboration
Mark Oreglia, ACFA-6, December 2003
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Energy resolution for sampling W
calorimeters
Photons
Si-W design (SLAC/Oregon) =>
cost and minimal RM require
compromise on E resolution by
minimizing Si area (30 layers)
and (Si thickness (300 mm))
Scint-W design (Colorado) =>
inexpensive, more samples – but
poor granularity and larger RM
Si-W-Scint. Hybrid (Kansas, KGWW State)=> thin Scint. layers,
cheaper, more samples (incl. Si),
retain granularity, keep RM small
Mark Oreglia, ACFA-6, December 2003
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Si-W geometry
6-inch f
hexagonal
Si wafers
DC coupled
Read out 1000 pads
power challenge
• can dynamic
range be realized?
(0.1-2000 MIP)
•
Mark Oreglia, ACFA-6, December 2003
Transverse
segmentation
of 5mm x 5
mm possible
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Heat flow
Longest path = 1.4 m
Physical model tests in progress –
prefer to avoid adding Cu
Mark Oreglia, ACFA-6, December 2003
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Si-W imaging calorimeter
• SLAC: M. Breidenbach, D. Freytag, N. Graf, G.
Haller, O. Milgrome
– Electronics, Mechanical Design, Simulation
• Oregon: R. Frey, D. Strom
– Si Detectors, Mechanicl Design, Simulation
• BNL: V. Radeka
– Electronics
• 10 wafers due from Hamamatsu soon
– Readout chip in spring ??? (No GLAST delays!)
• 30 layer prototype in 3 years
Mark Oreglia, ACFA-6, December 2003
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Colorado work
Uriel Nauenberg, Choi, Dobos, Dorland, Erdos, Goodson, Gray,
Hahn, Martinez, Proulx
Scintillating tile with fiber
readout.
Can afford to build at
higher radius
Try to address granularity
issues with offset tile
geometry per layer
Considering pixels of 50mm x
50 mm area to allow 1mm fiber
curving
Mark Oreglia, ACFA-6, December 2003
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Simulation results
1.75 mm W; 2mm Sc ; 1mm gap
40 GeV
photons
Offset helps – but
position resolution at
low energy ??
Mark Oreglia, ACFA-6, December 2003
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Iowa Crystal effort
Usha Mallik, Matt Charles, & student
(U. Iowa) – Pb WO4 crystals from
Caltech (Zhu). Touted to have 10
light-yield of CMS. Exploring whether
crystals make sense for a LC detector
Group also working on reconstructing
muons in SD Si-W simulations to
develop expertise on p-flow issues
Mark Oreglia, ACFA-6, December 2003
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Hybrid Si-W-Scint. Calorimeter
• Kansas: G. Wilson, C. Hensel, E. Benavidez, D. Gallagher, J. Robbins,
P. Baringer, A. Bean, D. Besson
• Kansas-State: T. Bolton, E. von Toerne, Y. Fu, … getting started
Concept : Develop a cost-optimized
ECAL with most of the advantages of
the Si-W concept, but finer sampling,
excellent time resolution and cost which
permits placement at larger R.
Mark Oreglia, ACFA-6, December 2003
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HY75
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1.4mm W plates
15 layers Si
60 layers of
1.5mm Scint.
4 layers ganged
(30 pe/mip) ( if
5pe/mip/mm)
15 super-layers each
with mip-detection
E res :
HY135
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•
•
•
HY42
0.778mm W plates
15 layers Si
120 layers of 1mm Sc
8 layers ganged (40
pe/mip)
• 15 super-layers
• 2.5 mm W plates
• 14 layers Si
• 28 layers of 2 mm
Sc
• 2 layers ganged
(20 pe/mip)
• 14 super-layers
10.4%/E
7.7%/E
14.3%/E
Moliere radius : 19.3 mm
21.4 mm
16.5 mm
33% of the
Silicon
cost
(SDMar01 30X0 W : 15.4%/E, 15.5 mm)
Mark Oreglia, ACFA-6, December 2003
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Emerging Case for Digital HCAL
Optimize application of Energy Flow Algorithms
Separation of different components of jets
Extremely fine segmentation of readout
Readout pads of order of 1 cm2
Layer-by-layer readout
But we still need to verify
this in a test beam!
Readout
Digital (1 bit resolution)
Semi-digital (say 2 bit resolution)
Energy resolution preserved in MC simulation studies
Mark Oreglia, ACFA-6, December 2003
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Challenges
Develop active medium with required granularity in readout
Reduce cost of electronic readout to O($1/channel)
Intermediate goal
Construction of 1 m3 prototype section
400,000 readout channels
Ongoing R&D efforts
Scintillator
Gas Electron Multipliers (GEMs)
Resistive Plate Chambers (RPCs)
Mark Oreglia, ACFA-6, December 2003
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Scintillator DHCAL
Concept
Northern Illinois University
Scintillator thickness 5 mm
Hexagons of 9.4 cm2 area
Trade-off segmentation with readout resolution
Considering 2 – bit readout (= 3 thresholds)
Non-projective geometry
Mark Oreglia, ACFA-6, December 2003
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Prototype stack
20 mm steel plates
12 active layers with 7 tiles each
→ 7 layers instrumented
Tests with cosmic rays
Mark Oreglia, ACFA-6, December 2003
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Readout with Silicon-PM
Light Collection
Has to work in B-field
Tests with Photomultipliers
Silicon Photomultipliers
Avalanche Photodiodes
Readout with PM
Readout with APDs: Hamamatsu S8550
~ 11 p.e./MIP
Mark Oreglia, ACFA-6, December 2003
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GEM DHCAL
University of Texas at Arlington
Concept
Gas volume for
ionization
GEM foils for
multiplication
→ perforated
Pads for signal pickup
9 channel GEM prototype
using electronics developed
for silicon readout (FNAL)
32 channel boards
3 mm gas gap
Mark Oreglia, ACFA-6, December 2003
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Mechanical studies
Build jig (thin side walls) to stretch foils
Develop procedure to glue spacers
Investigate use of absorber plates as mechanical structure for GEMs
Develop sliding techniques to insert GEMs in active gap
Electronic readout
Collaborate with FNAL (R Yerema) on front-end ASIC
- To be located on GEM
- 100 channels/chip
- Single readout cable/layer
Foil production
Collaboration with 3M corporation
in Austin, Texas
Production of 500 feet foils, 16” wide
Affordable: $2/GEM + overhead
Mark Oreglia, ACFA-6, December 2003
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RPC DHCAL
Argonne, Boston, Chicago, FNAL
Pick-up pads
Major effort to:
• prove reliable operation
• vindicate simulation work
• build cubic meter prototype for 2005
Mylar
Graphite
Signal
HV
Gas
Resistive plates
Both groups agree
Glass as resistive plates (NO permanent ageing ever observed)
Work in avalanche mode (reduced cross talk, higher rate capability)
Mark Oreglia, ACFA-6, December 2003
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US chamber tests
Two gas gaps of 0.64 mm each
Gas Freon:Argon:Isobutane = 62:30:8 (in the past)
Freon:Isobutane: SF6 = 94.5:5:0.5 (now)
Readout pads of 1 cm2
High efficiency, wide HV plateau
Little charge outside pad hit
Mark Oreglia, ACFA-6, December 2003
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Immediate plans
VME based multi-channel readout
6U x 160mm VME board
Contains 64 inputs
- shaper, amplifier, discrimintator
Records time-stamps of hits and hit patterns
Being commissioned
Measure efficiency, cross talk, noise rate…
More chamber tests
Comparison of two gaps with single gap
Design of larger chambers
for 1m3 prototype
Minimize dead area
Mechanical tests
3.0
Aluminum 0.2
5.0
(2.0)
Readout 2.5
3.0
Mylar 0.1
Graphite 0.1
Glass 1.1
1.1
Gas gap 0.65
0.65
Glass 0.85
0.85
Gas gap 0.65
0.65
Glass 1.1
Graphite 0.1
Mylar 0.5
Mylar 0.5
1.1
1.5
Aluminum 0.2
Mark Oreglia, ACFA-6, December 2003
Total 9.15 mm
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DHCAL Scorecard
Scintillator
• Proven technology
• Readout gaps of 6 mm possible
• Semi-digital readout applicable
• Larger tiles of ~10 cm2
GEMs
• Lower HV than RPC
• Segmentation of readout of 1 cm2 possible
• New technology
• Delicate technology
• Tiny signals
RPCs
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•
•
•
• Newer technology
• High HV of O(8-9 kV)
Cheap, simple, robust
Reliable
Segmentation of readout of 1 cm2 possible
Signals of O(1 – 3 pC)
Mark Oreglia, ACFA-6, December 2003
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