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BLAND. Particle Physics Design Group Studies. Big Liquid Argon Neutrino Detector Subgroup. The BLAND Group. Patrick Owen Resolution and Efficiency Laurie Hudson General design and Charge readout Stewart Hawkley Triggering and Event reconstruction - PowerPoint PPT Presentation
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Particle Physics Design Group Studies
Big Liquid Argon Neutrino DetectorSubgroup
Particle Physics Design Group Studies: The BLAND Subgroup
BLAND
The BLAND Group
• Patrick Owen – Resolution and Efficiency
• Laurie Hudson– General design and Charge readout
• Stewart Hawkley– Triggering and Event reconstruction
• Cheryl Shepherd and James Mugliston– Magnetics and Cryogenics
• Oliver Cartz and Jeanette Avon– Calibration and Background
• Dee Campbell-Jackson– Avalanche Photodiodes and Purification
Particle Physics Design Group Studies: The BLAND Subgroup
Introduction• General Setup and Material Choice• Collection Plate• Magnetisation• Photomultipliers• Electronics• Calibration • Background and Location• Purification• Triggering• Simulations• Sensitivity & Resolution• Cost• Summary
Particle Physics Design Group Studies: The BLAND Subgroup
General Setup
Particle Physics Design Group Studies: The BLAND Subgroup
-Tank has cylindrical geometry
- Gaseous argon at the top for bi-phase LEM that will used in charge readout.
- Non-magnetic tank and dome.
- Anti-coincidence shield
- This will all be contained within a cryostat. (Liquid Nitrogen)
- Magnet & a return yoke to provide a uniform B field.
Near Detector
• Exactly the same (except size)
• Cylindrical shape
• 6m diameter, 5m height
• Identical in functionality -
• Used for measuring cross sections and initial energy spectrum
Particle Physics Design Group Studies: The BLAND Subgroup
Material Choice
Particle Physics Design Group Studies: The BLAND Subgroup
• $0.6 kg-1 ≈ $10 million (for 1 detector)
• High density (1.4 gcm-3) and stability.
• εr = 1.6
• μ = 475 cm2V-1s-1
• High scintillation yield; 40,000 γ per MeV
• Background rejection of NC and junk CC interactions
Collection Plate
Particle Physics Design Group Studies: The BLAND Subgroup
• Far detector - magnetises ~ 17 kTonnes of liquid argon• Solenoid produces a uniform field of 0.55 T • Correction currents with a return yoke• Total coil ~ 5.5 kTonnes• Iron yoke ~ 16.1 kTonnes• Magnet Cooling system• Feasible power consumption of 19.2MW
Magnet
Particle Physics Design Group Studies: The BLAND Subgroup
BLAND magnet demonstration
Particle Physics Design Group Studies: The BLAND Subgroup
Simulation result
Particle Physics Design Group Studies: The BLAND Subgroup
Photomultipliers• Avalanche photodiodes (APD)– Small size– Low dead time
• Low temperatures• High B-field• Gain 106
Electronics
Particle Physics Design Group Studies: The BLAND Subgroup
• Current collected is of order pC.• Install pre-amps inside cryostat to reduce capacitance.• Extended lifetime of electronics• High signal: noise ratio• 4 bytes per digitisation, 2.5MHz.• Bandwidth distributed around PC farm.
Pre-amplifier ADC
Collection Plate
Cryostat
Calibration
• Why calibrate?• Initial– Signal Level-> Energy– Test beam– Cosmic ray muons (anti-coincidence shield)– Electronics
• Ongoing calibration– Constantly changing variables– Correction factors– Cosmic ray muons
Particle Physics Design Group Studies: The BLAND Subgroup
Before
After
Background
• Projected direction• Known energy range• Location• Expected background:– 10-8 s-1 neutrinos– 1s-1 cosmic ray muons at 1km underground
Particle Physics Design Group Studies: The BLAND Subgroup
Location
• Underground• Low background radiation• Few nuclear power plants• High available energy• Existing underground facilities
Particle Physics Design Group Studies: The BLAND Subgroup
Particle Physics Design Group Studies: The BLAND Subgroup
• Average data rate ~45MB/s.• Trigger above background pedestal.• Scintillation light detected by PMTs used to trigger for 'interesting'
events.• Effectively segments detector, only reading out locally active regions.• An anti-coincidence shield is used to reject background.
Triggering
Purification of LAr
Particle Physics Design Group Studies: The BLAND Subgroup
• Electron drift ~ 25m• Minimisation of
recombination• Purity of <0.1ppb
– Monitor contact materials– Hermetic system– Continual purification
• 100Watts
Purity Testing
Particle Physics Design Group Studies: The BLAND Subgroup
Schematics Signals
Simulations
Particle Physics Design Group Studies: The BLAND Subgroup
Particle Physics Design Group Studies: The BLAND Subgroup
Particle Physics Design Group Studies: The BLAND Subgroup
Charged current muon production
Charged current electron production
Incident neutrinos
Sensitivity
Particle Physics Design Group Studies: The BLAND Subgroup
The QECC cross section (red line) is found to be 7.5x10-43 m2 and 6x10-43 m2 for the far detector and middle detector respectively (Half these values for antineutrinos).
http://www.fnal.gov/directorate/DirReviews/Neutrino_Wrkshp_files/Fleming.pdf
Sensitivity
Particle Physics Design Group Studies: The BLAND Subgroup
1310)42.01.2(tnW QECCFar
1310)34.07.1(MiddleW
The average active thickness for the detector, t = 2d/π =14.1m
The number density under the average pressure, n = 2.0x1028
d =22m
Again these values are halved for antineutrinos
Energy Resolution• A 1GeV electron will ionise 1.45x107 atoms• The contribution from quantum fluctuations is
• Another contribution is from the time resolution which is a systematic error.
• Noise and avalanche variation is expected to be negligible.• Other effects such as electronics and dead zones.• These values are best estimates.
)(
%026.0)(
GeVEE
E
E
E stochastic
Particle Physics Design Group Studies: The BLAND Subgroup
%02.0)()()(
t
Q
Q
E
E syst
Momentum Resolution• Spatial resolution arises from diffusion and channel size• Total spatial resolution is 6.7mm• Momentum resolution:
• Radiation length calculated to be 5.6km – multiple scattering contribution is negligible.
• Heavily dependent on path length, L – not constant.
4
720
cos3.0
)()(2
NBL
pr
p
p
i
Particle Physics Design Group Studies: The BLAND Subgroup
Particle Physics Design Group Studies: The BLAND Subgroup
Average fractional momentum resolution is 1% and 3% for the middle and far detectors respectively (worse than energy resolution).
Momentum Resolution
0 5 10 15 20 250.0001
0.001
0.01
0.1
1Fractional Momentum Resolution vs Path Length
Middle DetectorFar Detector
Path Length (m)
Fractional Momentum Resolu-tion
Cost
Particle Physics Design Group Studies: The BLAND Subgroup
Equipment Number Cost ($)
Liquid Argon 2x17KT + small 25 mil
Magnet & Yoke 2 24 mil
PMs (1/m2 ) ~4000 120 k
Liquid Nitrogen 2x104 m3 2 mil
LEM Channels + E-field 12x106 12 mil
Underground factor n/a 2
PC Farm 1 10 mil
Contingency n/a 80 mil
Engineers & Scientists 200 48 mil (over 6 years)
Total 264 mil + running costs
Summary…• Liquid Argon Time Projection Chamber• LEM readout• Uniform 0.55T B-field• Triggering using APDs• Calibration using test beams• Underground• Data Rate 45MB/sec• Purity < 0.1ppb• Great energy resolution, good momentum
resolution• Cost ~ $264 mil + running costs
Particle Physics Design Group Studies: The BLAND Subgroup
References
• Neutrino Scattering in Liquid Argon TPC Detectors, Fleming.
• Radiation Detection and Measurement; 2nd ed, Knoll.
• Measurement of the muon decay spectrum with the ICARUS liquid Argon TPC, ICARUS Collaboration.
• Detectors for particle radiation, Kleinknecht.
• Calorimetry, Wigmans.
Particle Physics Design Group Studies: The BLAND Subgroup
Questions?
Particle Physics Design Group Studies: The BLAND Subgroup