1. SCINTILLATING DIGITAL HADRON CALORIMETER
STATUS AND PLANS
ALEXANDRE DYCHKANT
FOR NICADD/NIU AND UIC
Northern Illinois University (DeKalb, IL 60115)
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2. CORNELL LINEAR COLLIDER WORKSHOP
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. CELL’S SCANNER VIEWS
PLANS
SUMMARY.
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3. CORNELL LINEAR COLLIDER WORKSHOP
INTRODUCTION
In order to get the most out of the potential anticipated from a future e+e- Linear Collider (LC) the di-jet mass must be measured to a precision of about 3 GeV, or, in terms of jet energy resolution, σ(E)=0.3√E, [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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4. CORNELL LINEAR COLLIDER WORKSHOP
Energy Resolution
single threshold
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5. CORNELL LINEAR COLLIDER WORKSHOP
N vs. E
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6. CORNELL LINEAR COLLIDER WORKSHOP
PROTOTYPE OF SDHCAL READY
FOR COSMIC TEST
ARRAY OF CELLS
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7. CORNELL LINEAR COLLIDER WORKSHOP
Note: Die provides exact shape and dimensions of product
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8. A BIG BLOCK OF PASSIVE MATERIAL (STEEL, BRASS, LEAD)
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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9. CORNELL LINEAR COLLIDER WORKSHOP
COSMIC STAND VIEW
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10. ARRAY ASSEMBLY OF COSMIC STAND WITH H8711 HOUSING
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11. CORNELL LINEAR COLLIDER WORKSHOP
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 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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16. 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 66
108 83 28 44 63
Mach./ Polish
127
130
128
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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20. CORNELL LINEAR COLLIDER WORKSHOP
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,
DEVELOP 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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22. CORNELL LINEAR COLLIDER WORKSHOP
SUMMARY
NICADD-FERMILAB EXTRUDER HAS PRODUCED FIRST SCINTILLATING STRIPS
SMALL SCINTILLATING CELLS ARE A REASONABLE APPROACH FOR DHCAL
TODAY’S 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.
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