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DRIFT-III Proposal for a Large Scale Directional Dark Matter detector @ SNOLAB Sean Paling - Sheffield University For the DRIFT Collaboration: Occidental College, University of New Mexico, Boston University, Imperial College, RAL, Sheffield, Edinburgh (UK Dark Matter Collaboration - UKDMC). - PowerPoint PPT Presentation
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SNOLAB-2005 Sean Paling - DRIFT
DRIFT-IIIProposal for a Large Scale
DirectionalDark Matter detector @ SNOLAB
Sean Paling - Sheffield University
For the DRIFT Collaboration: Occidental College, University of New Mexico, Boston University, Imperial College, RAL, Sheffield, Edinburgh (UK Dark Matter Collaboration - UKDMC)
SNOLAB-2005 Sean Paling - DRIFT
DRIFT-III: Phase ONE
Extension of current DRIFT-II programme @ Boulby mine.
An array of 10 low-pressure Negative Ion DRIFT TPC modules (≤10 kg target
mass, 10-8pb raw sensitivity)
DRIFT-II@Boulbymine
DRIFT-III phase ONE
Proposal: House phase ONE of DRIFT-III
@ SNOLAB
1st step & test-bed for scale-up to DRIFT-III - a 100+ module 100kg directional detector 10-9pb (raw) and 10-7/8 (directional) sensitivity
Will discuss:
• Motivation & concept
• Progress so far (DI/DII)
• DIII-phase ONE details &
requirements
SNOLAB-2005 Sean Paling - DRIFT
Why a Directional Detector?
12:00h
42o
0:00h
WIMP Wind
Galactic WIMPHalo
To provide THE most powerfulsignature of the existence WIMPs in the
galaxy - through unambiguous measurement of the WIMP wind.
SNOLAB-2005 Sean Paling - DRIFT
Moore et al.....Clumps
Tidal disruption streamsStiff et al..Freese, Gondolo et al.
Sun’s influenceFu-sin Ling et al.Sikivie, Wick et al
Sagittarius Stream - Freese et al.
No longer just the simple spherical, Isothermal Halo...• velocity space anisotropy• bulk rotation• substructure, clumps• triaxality, oblate vs. prolate• late accreted sub-halos• sub-structure on sub-pc scales• spikes and caustics
Later - WIMP Halo studies
Study the structure & dynamics of the Dark Matter Halo
WIMP arrival distributions
Spherical Isothermal
Tidal StreamLogarithmic Ellipsoidal
Different models produce different WIMP arrival directions/velocities
(B. Morgan, A. Green, N. Spooner - Astro-ph/040804)
SNOLAB-2005 Sean Paling - DRIFT
How to build a directional How to build a directional detector?detector?
DRIFT: A Low Pressure Negative Ion Drift TPC
(NITPC)Low Pressure TPC:• Low pressure target extends range of
WIMP nuclear recoils to a few mm.• 3D reconstruction possible by
combining 2D readout with signal timing analysis.
Negative Ion DRIFT:• Electron capture by electronegative
gas reduces track diffusion.• Diffusion of <0.5mm at 0.5m drift
length (1000v/cm)Electric Field
Scattered WIMP
Recoil Atom
Drift direction
MWPC Readout
Plane
Cathode
CSCS22
Problem: In solid or liquid targets <100keV recoil tracks ~ 1-100nm long
The DRIFT Concept
(Rediscovered by Martoff - Temple)
SNOLAB-2005 Sean Paling - DRIFT
DRIFT Backgrounddiscrimination• Based on signal ENERGY and
RANGE.• Nuclear recoils have a higher dE/dx
than background electrons or alphas.Gammas
Alphas
Nuclear Recoils
• Little / no gamma shielding!
• Competitive as hi-sensitivity, limit-setting detector.
The DRIFT Concept
Gamma discrimination of >106 so far demonstrated.
(Snowden-Ifft et al. NIM A 498 (2003), & - Kirkpatrick et
al, in preparation)
SNOLAB-2005 Sean Paling - DRIFT
167g Target (1m3, 40 Torr) (20 keV threshold)
Scale up: 100kg (10keV theshold)
Xe Enhancement: (50% Xe/CS2) (10keV threshold)
How Sensitive?
61 kg.d no events
36,500 kg.d no even
ts
36,500 kg.d no even
ts
Single DII module1 year
100kg DIII 1 year
(Preliminary)
100kg DIII 1 year50% Xe:CS2
Adding Xe potentially…• Increases sensitivity by factor ≤5• Greatly assists verification of +ve wimp signal (proprotion of Xe to C/S recoils) (P.F.Smith et al, Astroparticle Phys 22, 2005)
SNOLAB-2005 Sean Paling - DRIFT
Simulations for realistic (advanced) NITPC Detectors…• 40 Torr CS2, 1 kVcm-1 drift field• 200 mm resolution, 10 cm drift• SRIM2003 - recoil scattering and diffusion
40 keV S recoil in 40 Torr CS2 (SRIM)
Results depend on: (1) Halo Model(2) Reconstruction accuracy
(Can we tell the ‘sense’ of the track? - Head or Tail?)
IF recoil sense known 10-20 events needed, if unknown 100-400 events needed - to reject isotropy at 95% confidence in 95% of experiments.
What about ‘Halo’ Sensitivity?
How many WIMPs to verify directionalHalo signature?
(B. Morgan, A. Green, N. Spooner - Astro-ph/040804,also: B. Morgan, A. Green - in preparation).
‘Halo sensitivity’ is between factor 10 & 100 behind raw detection sensitivity (depending on halo model and detector technology).
SNOLAB-2005 Sean Paling - DRIFT
DAMA
1000 GeV100 GeV
mssmRoszkowski et al.
Edel II, CDMS II, Zep II, DRIFT-II..
scale-ups
1 ton
100 ton
~1 event/100kg/year
~1 event/10ton/year
2003
2006
2010
2020
Edel I, CDMS I, Zep I, DRIFT-II..
No signal Signal found
10-6
10-7
10-8
10-9
10-10
10-11
10-5
10-12
Pb
100kg DRIFT & the World DM Search
Next Steps:Galactic confirmation- directionalityhalo studies
DRIFT-III
Detectionsensitivity
Halosensitivity
DRIFT-IIIPhase ONE
SNOLAB-2005 Sean Paling - DRIFT
The DRIFT Programme
2000 2001 2002 2003 2004 2005 2006 2007
1997-2002: Concept development, gas tests,
simulations 1ft3 NITPC prototype studies.
DRIFT-I: 1m3 (167g) NITPC.
Development, installation/operation
@ Boulby
DRIFT-II: 3(+) 1m3 (0.5-2kg) NITPC
Development, installation/ operation
@ Boulby
Scale-up R&D: Simulations, readout,
reconstruction, cost, engineering.
Surf commission - Sheffield
Install (May 05))
Operation
Surf commission - Oxy
Install (Jan 02))
Operation
Boulby Mine (UK)2805 mwe
DRIFT-II, Phase ONE (10 modules): Installation
2007/8
SNOLAB-2005 Sean Paling - DRIFT
DRIFT-I
• 1m3 Dual Negative Ion DRIFT TPC• 1.4m3 vac vessel - 40 Torr CS2 (167g fiducial)• Back-to-back 0.5m3 DRIFT regions.• MPWC readout (512 20m anodes, 2mm pitch)• DAQ: 2512 chan 1S sampling.
Installation 2001/2, Operation 20022004
DRIFT I: 1st large-scale DRIFT detector.
MW
PC
layout
DR
IFT-I @
Boulb
y
UKDMC, Occidental, Temple
SNOLAB-2005 Sean Paling - DRIFT
DRIFT-I
Outcomes• Demonstration of safe, stable, long-term operation UG .• Demonstration of event characterisation/discrimination.• Measurement of rock neutrons• Early verification of high gamma discrimination (>106)
Alner et al, NIMA, 535 (2004), Kirkpatrick et al (2005) - in preparation
Status• Some technical/engineering difficulties (DAQ, MWPCs, Fatigue). Moved on to apply numerous design/engineering lessons learned to DRIFT-II
SNOLAB-2005 Sean Paling - DRIFT
DRIFT II
Advanced, multi-module (3+) detector with sensitivityof ~10-7pb. Using lessons from DI and R&D.
• Aim:
(Factor 5 cost-reduction per module vs. DRIFT-I)
DR
IFT
-IIa @
Bo
ulb
y
1st step toward large scale multi-module upgrade
• Basic Design
• 3(+) 1m3 fiducial vol, NITPCs
• Back-to-back drift vols, dual MWPC readout
• Vertical planes, Warp adjust strongback MWPCs
• Improved (3d) track reconstruction (anode, grid and z-drift) (resolution: 2mm(x), 0.1mm(y), 0.1mm (Z))
• Low noise / cost 0.5S sampling (grouped) DAQ
• Improved vessel design (<10-8T.L.s-1) .
• Improved gas system (varied gas pressure & mixtures)
Robust, simple, reproducible & cost-reduced…
SNOLAB-2005 Sean Paling - DRIFT
DIIa - Construction & Commissioning
Side-oriented back-to-back field cages with rigid Cu piping.
1.5m3 cubed stainless steel vacuum vessel (UK/USA)
MWPCs, 512 20um anode wires: lucite frame with warp-adjust bars
Grid amplification & grouping, prior testing.
Inner detector stack
November 2004
SNOLAB-2005 Sean Paling - DRIFT
Boulby Mine - The JIF Area
Dark Matter ‘JIF’ Area
Stub BStub A
Low BGLab
>2.0m
ZEPLIN - II
>2.0m
123
ZEPLIN - III
Exhaust CS2 sensor Data acquisitionsystem
Detectors / VacuumChambers
gas systems, fume hood & extraction hose
DRIFT-I Lab
Mess
Gas/fire sensorcontrol
Entrancecorridor
CS2sensor
Late 2004
~100m
>1500m2 floor space (5m3.5m cross section)2T full XY craneCommunications, workshopStorage, clean room
DRIFT-IZEPLIN-II
DRIFT-II
Boulby Mine (UK)2805 mwe
SNOLAB-2005 Sean Paling - DRIFT
DRIFT II Status (July-Aug 05)
Construction/installation of modules b & c underway (full operation early 2006)
Next steps: - erect 40g.cm-2 neutron shielding (Polypropylene pellets in wooden support structure).
(Completion this week - followed by start of running shielded)
DIIb
DIIa
Gas / vacuum system tests. Neutron, alpha, gamma/X-ray calibrations, directed neutrons (directionality).• Demonstrated long term operation & stability (5 weeks continuous running - for pre-shielded data).
DIIa - fully installed, underground commissioning complete.
SNOLAB-2005 Sean Paling - DRIFT
Towards DRIFT-III (100kg)
Phase ONE (2006/7):1st 10 detectors:101m3 (fiducial), 40-240Torr (up to 10kg), 10-8pb raw sensitivity per yr.- forerunner to full extension of array.
This proposal
• Site/technology constraints on size.• Allows staged construction/installation• Minimises down time• Module comparisons (diagnostic. array)• Variable configuration/siting.• Cost (etc) benefits of mass production.
Why multi-module?
DRIFT-III Concept:
• Mass Production of 100(+) advanced, robust, reliable, stable & safe, NITPC modules. • 100kg total fiducial mass, 10-9pb (10-7/8pb) raw (directional) sensitivity (per yr).• High resolution 3d readout, high pressure (≤240 Torr) CS2 (or other).• Time-scale: Installation 2010?
DRIFT-III
SNOLAB-2005 Sean Paling - DRIFT
Scale up R&D
Minimize costs
‘head-tail’ discrimination
Improved resolution readout.
10(+) better directionality
higher pressure - lower volume
‘Z fiducialisation’
Alternative gases/mixture Increased sensitivity, WIMP signal verification
Specific technical R&D issues:
Improved track resolution, BG rejection.
Optimizedesign /
performance
DRIFT-III R&DReduceBackgrounds
(Micromegas? GEMs? <50µm? - UKDMC, UNM)
(Cathode readout, diffusion - Oxy)
(Xe:CS2 mixture, CF4, etc - UKDMC/Oxy)
(Bragg curve of recoiling ions? - Boston, UNM, UKDMC)
SNOLAB-2005 Sean Paling - DRIFT
Costs
AIM: further reduce costs (through MASS PRODUCTION) to ~£20K (<$40) per unit inc. shielding
If successful: <£2-10M (material/equipment) for 100kg.(~£0.2M for DRIFTIII-phase ONE)
SNOLAB-2005 Sean Paling - DRIFT
Background reduction
M. J. Carson et al. Astropart. Phys. 21 (2004)J. Davies et.al, NIMA, 546 (2005)
DRIFT-III Neutron Background Simulations
Neutron background source excluding muons
Recoil yr-1
(10-50 keV)
Rock unshielded, and shielded by 60 g/cm2 CH2
1.6106, 0.03
Stainless vessel, and after internal 10 g/cm2 CH2
25, 0.4
All internal components (resistors etc.)
0.2
CH2 shielding itself 0.2
Total expected in detector with shielding
<1
GEANT4 (FLUKA & SOURCES)
Neutron (excluding muon-induced)For 100kg DRIFT @ Boulby
Muon-induced Neutrons @ Boulby ( 2805 MWE) n >50
DRIFT-III needs greater depth to avoid costly muon-veto...
@ SNOLAB (~6010mwe) n <1
SNOLAB-2005 Sean Paling - DRIFT
Size/space needed?
10 1m3 (fiducial) detectors (1.5m3 vessels), 50-60gcm-2 CH shielding,
Need ≤30m of tunnel - 3.3m cross section (inc gas system, staging, storage & control)
DRIFT-III phase ONE
Size/arrangement dependent on location.
Size dependent on technology and location.e.g: in a large hall - stacked design, ~2000(+)m3 needed.e.g: In a ‘corridor’ - linear design : ~300(+)m of tunnel with 3.3m cross section…
D-III could be split - more than one lab or UG site!
NEW areas dug? - cost of excavation @ Boulby estimated
>£1.M for 200m tunnel
Later scale-up: DRIFT-III (100+ detectors)
Is size a problem long term? - Not necessarily:
SNOLAB-2005 Sean Paling - DRIFT
EmergencyEgress
Large ExperimentalSpace
Utility Area
Smaller Drifts
DIII Phase ONE
SNOLAB Ladder Labs…
<30m
2 banks of 5 shieldeddetectors, gas system,
DAQ,storage/staging30m (3.3m2 cross sec)
SNOLAB-2005 Sean Paling - DRIFT
General facilities: • Transportation:10 detectors + vessels, support apparatus, 100T PP shielding.• 2T lifting capacity (crane/forks?)• ≤ 30m2 staging/material storage space. Moderate class clean room (<class 2000).• Power: 500W single phase per module (>10kW for 10 & support apparatus).• Light use of mechanical & electrical workshop• Moderate temperature stability (+/-2C)
Special requirements:• No cryogenics, vibration control, laser & optics, water purifcation. • Radioactive sources: Small (C) neutron. gamma & Alpha calibration sources.• Gases/Chemicals: Reduced CS2 quantity (sealed?). <15kg max.
Health & Safety:Main issues = CS2 target gas (100kg) and use of High Voltage.
By necessity for scale up (mass production / installation)DRIFT- III phase ONE = robust, stable, safe, low maintenance, low cost - low demand on infrastructure/services
Other Facility Issues
Proven safety record: No incidents in over 3 years operation @ Boulby
Fully compliant with stringent Boulby safety system (PIP). Comprehensive risk assessments, procedures, change control documentation produced & maintained.
DII safety documentation
SNOLAB-2005 Sean Paling - DRIFT
Funding & Schedule
Schedule:2005-7 DRIFT-II operation and scale-up R&D2006/7 Design development / review. Site preparation, 2007/8 Staged construction, installation, operation.2008+ Full operation, evaluation/R&D for upgrade to DIII2010? Staged installation of DRIFT-III.
Funding:• Estimated total cost. ≤£1M (eqpt, staff, R&D) - over 3-4 years.• DRIFT program currently funded by NSF (in US) & PPARC (in UK). European funding also becoming available.• Specific applications for DIII phase ONE will be submitted 2005/2006
DRIFT III phase ONE
SNOLAB-2005 Sean Paling - DRIFT
QuickTime™ and aYUV420 codec decompressor
are needed to see this picture.
A directional detector could provide THE most powerful signature for existence of WIMPs in the galaxy - DRIFT is far ahead of the pack in developing directional detector technology.
Now looking towards extending current programme to produce a large-scale 100kg detector (DRIFT-III) - giving 10-9pb (raw) sensitivity per year. Complement & compete with next non-directional detectors.
Phase ONE @ SNOLAB? - a REALISTIC 1st step in this upgrade: 10 modules with mass of up to 10kg and raw detection sensitivity 10-8pb per year. Forerunner to later upgrade.
DRIFT Technology = low maintenance, low impact on facility requirements. Low risk - proven record of safety & delivery at Boulby mine.
Summary
SNOLAB-2005 Sean Paling - DRIFT
DRIFT-IIIProposal for a Large Scale
DirectionalDark Matter detector @ SNOLAB
Sean Paling - Sheffield University
For the DRIFT Collaboration: Occidental College, University of New Mexico, Boston University, Imperial College, RAL, Sheffield, Edinburgh (UK Dark Matter Collaboration - UKDMC)
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