Sarah Minson Caltech February 22, 2011LLNL. Mark Simons (Caltech) James Beck (Caltech)
NO n A at Caltech
description
Transcript of NO n A at Caltech
NOA at Caltech
Leon Mualem
DOE Review
July 25, 2007
The NOA Detector~80 m
15.7 m
~16 kT total mass “Totally Active” granular
design Outstanding e pattern
recognition & measurement
Alternating X and Y views12 Extruded PVC Modules
per plane32 Individual cells per Module,
so 384 Cells per plane
Working to fit 260M AY$ TPC cap
NOA Tasks
Caltech Initiated or Responsible for many aspects of NOA
Hardware DAQ/Electronics Management APD Testing PVC Testing Fiber Testing Vertical Slice Tests
Software Framework Development Subshower Package Photon Transport simulation Supernova Sensitivity
Overview of Detector R&D
NOA Perform light output tests to understand the
components of the scintillator system [Ongoing] PVC extrusions, liquid scintillator, WLS fiber
Verification of scintillator system performance using a NOA APD [Ongoing]
Photon production and transport Monte Carlo [Ongoing]
Personnel – Jason Trevor, Leon Mualem + undergraduate
NOA Scintillator System Each cell an extruded TiO2 loaded PVC tube
with ID 60mm x 39mm x 15.7m long Cells are filled with mineral oil scintillator
which is read out at one end with a U-loop WLS fiber running to a multi-pixel APD
Kuraray 0.7 mm WLS Fiber Light output requirement determined by
achievable noise on the APD amplifier. The current estimate of minimum required Light Output is ~20-25 photoelectrons
One Cell
0.7mm WLS Fiber
R&D at Caltech Composition of the PVC cell walls Liquid scintillator composition Fiber diameter and dye concentration Fiber position Integration testing
Interface and Readout
Electronics Box
32 Pixel APD Photodetector Array
ManufacturerPixel Active Area 1.95 mm × 1.0 mmPixel Pitch 2.65 mmArray Size 32 pixelsDie Size 15.34mm × 13.64mmQuantum Efficiency (>525 nm) 85%Pixel Capacitance 10 pFBulk Dark Current (IB) at 25 C 12.5 pABulk Dark Current (IB) at -15 C 0.25 pAPeak Sensitivity 600 nmOperating Voltage 375 ± 50 voltsGain at Operating Voltage 100Operating Temperature (with Thermo-Electric Cooler)
-15ºC
Expected Signal-to-Noise Ratio (Muon at Far End of Cell)
10:1
APD channels per plane 384APD arrays per plane 12
APD Photodetector
Si Avalanche Photodiode
Custom design to match two-fiber aspect ratio
Bare die mounted to PCB via gold bump thermo-compression
Scintillator System R&D
Liquid Scintillator
Two competing mineral oil vendors (Parol, Ren) Competing vendors for additives Concentration of additives (pseudocumene,
PPO, Bis-MSB)
PVC Extrusions Three competing PVC formulations
(Prime, Aurora, NOvA collaboration) Two types of TiO2 (Anatase, Rutile)
Competing factors (extrudability, reflectivity, structural issues)
Test Setup
PMT
M16 PMT Box
“ Cell”
Lead
Scintillating Disc
1.2mm Clear Fiber
We are currently using a “NOA Cell” with internal dimensions 38.5mm x 60mm x 85cm.
Each end of the fiber “U” is connected to an individual pixel on an M16 phototube by 3.5m of 1.2mm clear fiber.
Fibers are held in a fixed position inside the cell by a pair of acrylic “spiders.” (More on this later)
For testing purposes I am using vertical muons from cosmic rays.
The cosmic ray muon telescope consists of two circular discs (~4 cm diam) separated by 14 cm and 1 inch of lead.
The “NOA Cell”
PVC
60mm
“NOA Cell”
38.5mm
The “NOA Cell” is actually a rectangular aluminum tube which is lined on the inside with the PVC we are testing.
More “NOvA Cell” Pictures
DataData from each fiber end is
collected and plotted separately
Because the rate is low (one event every 150 seconds), data is acquired over a long period of time (>72 hours) in order to obtain a statistically significant sample
Results: Scintillator Samples
Three scintillator samples, RenDix 517p, ParDix 517p, and RenAld517p.
Results show a 20% difference in light output between scintillators made with oil from Ren Oil and those made with oil from Parol.
Pseudocumene from different suppliers appear to perform similarly.
Measurements are highly repeatable.
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ParDix517P1
ParDix517P2
RenDix 517P RenAld 517P
Summed Light Output(PE)
Results: Extrusions We have tested several extrusion
samples. Shown here are our baseline extrusion, our best extrusion made with rutile Ti02, and our best Anatase extrusion.
We have also included two other samples for reference: A MINOS Strip The duplicate “NOA Cell”
painted on the inside with BC-620, an acrylic based paint loaded with TiO2(Anatase).
All measurements were performed with RenDix 517P
Initial results show we can do better that the minimum light output specification.
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Minos Strip Pet B(Baseline)
BB15R AnatasePaint
BB18A
Summed Light Output (PE)
Minimum Spec.
Upgraded Test SetupPMT
M16 PMT Box
Actual Cell
Lead
Scintillating strip
1.2mm Clear Fiber
Increased trigger sizes.More than triple the rate, no effect on precision.
Testing apparatus is otherwise unchanged
Increased throughput of system; limited by sample preparation time,instead of trigger rate.
Extrusion tests
More Extrusion Results Tests of recent
extrusions show high and consistent light output compared to previous recipes.
Recent extrusions have also extruded well mechanically.This is CRITICAL to integrity of the detector:
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60Series BSeries CSeries D
Caltech Mini Mini Tracker
Minos Scintillator
Trigger
Minos Scintillator
Trigger
FRONTVIEW
SIDEVIEW
16.4 cm 30 cm
60cm
40c
m
150ppm1 2 3 4
300ppm
250ppm N N
1” Lead
“N” = Near length fibers
Actual Device
Not as photogenic, but: Uses prototype APD 33.4m fiber
(Actual length) It works
300 ppm results
Far Light Output vs. Concentration
Measurement Summary
150 ppm 24 pe’s Significant spread, 20-35
250 ppm 22 pe’s Very small spread (only 2 samples)
300 ppm 35 pe’s Range: 30-40 3 with ~10% spread
NOA Software at CaltechWe developed a set of light weight libraries
(“SoCal”) to allow people to access NOA data and information in C++/ROOT.
SoCal consists of:Data format for NOνANOvA geometry and electronics connection mapEvent display packageDetector & Electronics response simulation toolsFull (and up to date) documentation.Tools to help people write further packages.
Used by the collaboration to develop reconstruction and analysis used for TDR
SoCal
Caius Howcroft
Caius Howcroft
Decay chain
BrandingEvent Source
Reco'ed event
True Hits e/μπp
Colour = energy deposited
Event Display
Caltech Reconstruction:“Subshower” Code [HZ, CH]
3D shower & Track-like feature reco.
Now the standard in MINOS
Has been applied to NOA
Preliminary use by Bob Bernstein at Fermilab shows significant signal/background separation
Needs to be carried through to a complete analysis [e.g. Patterson]
“Raw Data”
Sub Showers
Caius Howcroft
Detector Simulation Detector simulation code that models the light output
of the scintillator, the collection of WLS fiber and the propagation to the APD, “PhotonTransporter”
Tracks individual photons and correctly deals with wavelength dependent absorption, reflection and emission coefficients.
Has been used to understand results from the Caltech test-stand and in production MC.
Accurately reproduces features of measured light collection in a cell
Caius Howcroft
Charged Particle
Simulated Cell
WLS FibersPhoton
Simulations of Light Output vs. Position
Fiber Position Results Light Yield Simulation
suggests light output decreases as fibers approach walls
Effect seen in test stand data, but magnitude smaller than predicted
Tune simulations with data to reproduce changes quantitatively
Background Studies
NOA is a search for a small signal
Understanding and correctly modeling the background is important
Work at Minnesota demonstrated the need for an overburden
This work also showed potential for Supernova detection with the overburden
Additional effort needed to determine sensitivity, and computing requirements to search for small signal events
Find the SuperNOvA
31Leon MualemNOvA Electronics
~15min of data With typical ~10s supernova signal
1s time binsNO OVERBURDEN
Find the SuperNOvA
~15min of data With typical ~10s supernova signal100ms time bins
1m OVERBURDEN
Software / AnalysisCreated the Framework used for NOvA software
development and TDR analysisThis base now being expanded to add features
Created the Subshower analysis package for MINOS, ported to NOvA frameworkShowing promising results by Bernstein@FNALNeeds to be carried through to a complete
analysisCreated Photon propagation code
Generally useful for understanding light collection and detector performance
Validation with actual test data continues
Caltech Work on NOA WLS Fiber R&D
Examined the effect of fiber diameter on light collection in the NOA geometry (The reduction to 0.7mm WLS Fiber saved $3 million+)
Measured light output for fibers with varying fluor concentration, ongoing optimization
Examine the effect of fiber position inside the NOA cell on light collection, ongoing input to simulation
Optical Readout System Verify scintillator system performance using the NOA
APD, original and prototype versions Quantify results of production variability using different
plastic samples, many cells and fibers Gain experience using the new NOA APD in small scale
prototype modules
SummaryNOA
Caltech has taken a leading role in NOA detectorhardware R&D Measurements done thus far at Caltech have
been, and continue to be instrumental in the detector design process
We will continue to make contributions central to the detector development effort throughout the next year
We will continue to define the detector performance and identify unique capabilities, such as supernova detection
The arrival of Ryan Patterson will add considerable strength, allowing us to build on our founding roles in NOA software and analysis