SCINTILLATING DIGITAL HADRON CALORIMETER

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SCINTILLATING DIGITAL HADRON CALORIMETER STATUS
AND PLANS
ALEXANDRE DYCHKANT FOR NICADD/NIU AND UIC
Northern Illinois University (DeKalb, IL 60115)
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CONTENTS
INTRODUCTION PLOT 1. AN ENERGY RESOLUTION
PLOT 2. NUMBER OF HITS VS. ENERGY
PICTURE 1. A PROTOTYPE
OF SDHCAL PICTURE 2. AN EXTRUDER
AND DIE COSMIC STAND SCHEMATIC
PICTURE 3. COSMIC STAND PICTURE 4.
AN ARRAY ASSEMBLY WITH HOUSING PLOT
3. A DISTRIBUTION OF OUTPUT SIGNAL
COSMIC MEASUREMENTS WITH
H8711 PROTOTYPE OF SDHCAL PICTURE
5. A STACK ASSEMBLY AND ARRAYS VIEWS
PLOT 4. QUALITY CONTROL FOR STACK CELLS
COATING/WRAPPING OF CELLS, GEOM ETRY
PLOT 5. CELLS RESPONSES TABLE 1.
CELLS RESPONSES OPTICAL CROSSTALK BETWEEN CELLS
PICTURE 6. CELLS SCANNER
VIEWS PLANS SUMMARY.
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INTRODUCTION
In order to get the most out of the potential
anticipated from a future ee- Linear Collider
(LC) the di-jet mass must be measured to a
precision of about 3 GeV, or, in terms of jet
energy resolution, s(E)0.3vE, E in GeV. Now
the most promising way to achieve such
resolution is through energy flow algorithms
(EFA). Excellent energy flow calorimeter must be
finely segmented both transversely and
longitudinally for 3D shower reconstruction, so
in strong magnetic field hits initiated by
charged particles can be separated from those
initiated by neutral particles. As a possible
solution, our group at the Northern Illinois
Center for Accelerator and Detector Development
(NICADD) has undertaken a comprehensive
feasibility study of a finely segmented
scintillating sampling hadron calorimeter. The
very large number of readout channels pose a
significant challenge in the form of complexity
and cost. Reducing the dynamic range of readout
is a potential solution. At the extreme, it can
be a digital calorimeter with a one bit readout
for each cell, with the threshold set to detect
the passage of a minimum ionizing particle.
Optical part of scintillating digital hadron
calorimeter includes scintillating cells,
optical fibers, and photo detectors. We are
going to use an extruded scintillator to reduce
the price. Fibers and photo detectors can be the
most costly part of a project.
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Energy Resolution
single threshold
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N vs. E
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PROTOTYPE OF SDHCAL READY
FOR COSMIC TEST ARRAY OF CELLS
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Note Die provides exact shape and dimensions of
product
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COSMIC STAND
TRIGGER COUNTER 1
THIS COUNTER IS UNDER INVESTIGATION
A BIG BLOCK OF PASSIVE MATERIAL (STEEL, BRASS,
LEAD)
TRIGGER COUNTER 2
TRIGGER COUNTER 3
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COSMIC STAND VIEW
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ARRAY ASSEMBLY OF COSMIC STAND WITH H8711 HOUSING
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DISTRIBUTION OF OUTPUT SIGNALS FROM H8711
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MEASUREMENTS WITH H8711
COSMIC STAND PROVIDES TRIGGER OF PARTICLES WITH
TRACKS PERPENDICULAR TO ARRAY OF CELLS 1.5 ? OF
MATERIAL CAN BE INSTALLED BETWEEN THE COUNTERS
WE USE VME CRATE WITH QDC V792 WITH LABVIEW
DAQ EACH CELL, MADE FROM 5 MM THICK
BC408 SCINTILLATOR , HAD A HEXAGONAL SHAPE WITH
3 MM DEEP SIGMA GROOVE, 9.4 CM² KURARAY Y-11
WLS FIBER WITH MIRROR END WAS GLUED INSIDE AND
SPLICED TO 2 M LONG CLEAR FIBER Ø 0.94
MM, TOP CHART SHOWS A MIP RESPONSE, MIDDLE AND
BOTTOM CHARTS SHOW THE RESPONSE OF LED SIGNALS
SIGNIFICANTLY ATTENUATED WITH FILTER TO GET
SES USING THE POISSON DISTRIBUTION THE
ESTIMATED AMOUNT OF PE ARE 0.95 AND 0.6
ACCORDINGLY, MPMT SHOWS APPROXIMATELY 10 PE.
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PROTOTYPE OF SDHCAL FOR 3D MEASUREMENTS WITH
COSMIC RAYS
CELL ARRAY
MATERIAL SCINTILLATOR BC408, THICKNESS 5
MM, SHAPE HEXAGON, LENGTH OF SIDES- 19
MM, AREA- 9.4 CM²,
GROOVE SIGMA SHAPE, RADIUS 12 MM, 25º
OF CIRCLE WITHOUT GROOVE,
RECTANGULAR CROSSECTION, DEPTH 4 MM, WIDTH
1 MM, DEPTH TAPERED
TO EXIT,
WLS FIBER BCF92, DIAMETER 0.8 MM, LENGTH- 1
M, FINISHED ENDS
WITH FLY DIAMOND TECHNIQUE, ONE END AL
MIRRORED, EMBEDDED AND THEN GLUED
INTO THE GROOVE USING BC600
7 CELLS IN EACH, EMBEDDED INTO PLASTIC BOX WITH
LID, 125 MM X 125 MM X 9MM EACH OF THEM, TWO
ARRAYS CONNECTED TO ONE CMS TYPE OPTICAL
CONNECTOR, FINISHED WITH FLY DIAMOND TECHNIQUE,
STACK 12 ARRAYS, 6 CMS TYPE OPTICAL
CONNECTORS, 6 HAMAMATSU H8711 MPMTs, 84
CHANNELS CONNECTED TO QDC, 13 LAYERS OF
PASSIVE MATERIAL, 125 MM X 125 MM X 25 MM,
WEIGHT 100 POUNDS
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CALORIMETER PROTOTYPE ASSEMBLY AND ARRAYS VIEW
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STACK CELLS QUALITY CONTROL
FIRST MEASUREMENT OF RESPONSE OF EACH CELL WAS
PERFORMED BEFORE GLUING FIBERS INTO OPTICAL
CONNECTOR IT WAS DONE AT FERMILAB SECOND
MEASUREMENT OF RESPONSE OF EACH CELL WAS
PERFORMED USING SCANNER IT WAS DONE AT NIU
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CELLS RESPONSE OF DIFFERENT COATING/WRAPPING
THE REASON FOR CARRYING OUT THESE MEASUREMENTS
WAS THE LACK OF DATA ON RESPONSE OF A SMALL
SCINTILLATING CELL WITH POLISHED EDGES COMPARED
TO THE RESPONSE OF CELL WITH NON-POLISHED OR
JUST MACHINED EDGES AND HOW ARE THESE RESPONSES
SENSITIVE TO A DIFFERENT WRAPPING OR COATING
MATERIALS.
GEOMETRY, MATERIALS, AND TOOLS
CELL MATERIAL SCINTILLATOR BC408,
THICKNESS 5 MM, SHAPE HEXAGON, AREA-
9.4 CM², 5 CELLS HAVE FINISHED EDGES
ALL TOTAL-11 CELLS.
GROOVE SIGMA SHAPE, RADIUS 12 MM, 25º OF
CIRCLE WITHOUT GROOVE, RECTANGULAR
CROSSECTION, DEPTH 4 MM, WIDTH 1
MM, DEPTH TAPERED TO EXIT.
WLS FIBER BCF92, SQUARE, SIDE 0.8 MM, LENGTH- 1
M,FINISHED ENDS, ONE END MIRRORED,
EMBEDDED AND GLUED INTO THE GROOVE
USING BC600.
WRAPPING MATERIALS TYVEK, 3M CM500, 3M CM590,
3M VM2002, ALUMINIZED MYLAR,
TITANIUM WHITE ACRYLIC PAINT FROM LIQUITEX
ENGLAND, (ALUMINUM FOIL).
PHOTOMULTIPLIER TUBE HAMAMATSU R580, HIGH
VOLTAGE 1300V, DARK CURRENT
LESS THAN 0.07
NA, OR LESS THAN 0.1 WITH Sr90 (2 mC) Note
Painting is the most attractive solution because
of high productivity.
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A FULL SET OF MEASUREMENTS FOR EACH CELL
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TABLE 1. RATIO OF CELL RESPONSE TO TYVEK (IN
PERCENTAGES)
Cell type Tyvek Paint VM 2002 Mylar CM590 CM500 Alum Foil
Polish Edges 100 64 107 81 31 46 67
Mach. Edges 100 66 108 83 28 44 63
Mach./ Polish 127 130 128 130 114 119
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OPTICAL CROSSTALK BETWEEN CELLS
ARRAY OF 7 CELLS CONNECTED TO ONE PMT R580
VIA SQUARE LIGHT GUIDE, DARK CURRENT WAS 0.4 nA
OR LESS THAN 0.2 OF OUTPUT CURRENT WITH Sr90 (5
mC), THE TOP CONFIGURATION OF CELLS CAN PROVIDE
AN ADDITIONAL LIGHT OF CENTRAL CELL TO ALL SIX
NEIGHBOURS THROUGH SIDES, IN THE BOTTOM
CONFIGURATION THE CENTRAL CELL STILL CONNECTED
TO PMT, BUT CANNOT PROVIDE THE ADDITIONAL LIGHT
TO NEIGHBOURS, FOR CELLS PAINTED IN WHITE
ACRYLIC ONLY, THE TOP CONFIGURATION PROVIDES 5
LARGER RESPONSE THAN THE BOTTOM ONE, OPTICAL
CROSSTALK IS 5 PER CELL.
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SCANNER VIEW WITH PMT AND RADIOACTIVE SOURCE
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P L A N S
GET FIRST RESULTS WITH COSMIC RAYS USING
PROTOTYPE OF SDHCAL AS A 84-CHANNELS-3D
TRACKER, GET FIRST RESULTS WITH H7546B, APD
S8550, SiPM, ETC PHOTO DETECTORS, MEASURE THE
CELL RESPONSE WITH DIFFERENT DIAMETER OF FIBERS
AND DIFFERENT THICKNESS OF SCINTILLATOR IN ORDER
TO GET A THICKNESS OF ACTIVE LAYER LESS THAN 6
MM, DESIGN, BUILD AND TEST FULL SCALE MODULES OF
16 (32) CELLS FOR TEST BEAM MEASURE THE PMT R580
UNIFORMITY RESPONSE WITH AND WITHOUT THE LIGHT
GUIDE, MEASURE THE MPMT H8711 UNIFORMITY
RESPONSES, BUILD A NEW SCANNER, WITH REFERENCE
CELL AND WELL DEFINED HOME POSITION FOR THE
RADIOACTIVE SOURCE IT SHOULD PROVIDE ON-LINE
SCAN OF CELL ARRAY(S) USING A PREDEFINED
COORDINATE FILE OF POINTS OF MEASUREMENTS, DEVELO
P A PHOTOGRAMMETRIC METHOD OF SURVEYING
SCINTILLATING CELLS ON LINEAR COLLIDER
DETECTOR WITH A PRECISION OF 0.1 MM IN ALL
DIMENSIONS.
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SUMMARY
NICADD-FERMILAB EXTRUDER HAS PRODUCED FIRST
SCINTILLATING STRIPS SMALL SCINTILLATING CELLS
ARE A REASONABLE APPROACH FOR DHCAL TODAYS
DESIGN OF OPTICAL ELEMENTS PROVIDES 10 PE THE
3M SUPERREFLECTIVE FILM VM2002 PROVIDES THE
BRIGHTEST RESPONSE. A PAINTED CELL PROVIDES 2/3
RESPONSE OF CELL WRAPPED IN TYVEK, BUT PAINTING
IS MORE PRODUCTIVE THAN WRAPPING OPTICAL
CROSSTALK BETWEEN WHITE PAINTED CELLS IS
SMALL PROTOTYPE OF SDHCAL IS ALMOST READY FOR
COSMIC TEST DIGITAL HADRON CALORIMETER WITH
SMALL SCINTILLATING CELLS IS A ROBUST SOLUTION
FOR THE FUTURE LINEAR COLLIDER DETECTOR.