Update of DRIFT-I r&d & status of DRIFT-II
Transcript of Update of DRIFT-I r&d & status of DRIFT-II
IDM2004
Update of DRIFT-I r&d& status of DRIFT-II
Sean paling-->Tim Lawson-->Neil Spooner
For the DRIFT Collaboration: (UKDM) Imperial College, RAL, Sheffield, Edinburgh, Occidental College, Temple, University of New Mexico*, Boston University*, Thessaloniki(+), Darmstadt(+)
*new, +new for KK axions
Objective: can we build a directional WIMP detector?
IDM2004
Electric Field
Cathode
Scattered WIMP
Recoil Atom
Drift direction
Readout
CSCS22
DRIFT: A Directional Dark Matter Detector
12:00h
42o
0:00h
WIMP Wind
Why?
• Provide the most powerful evidence for the existence of WIMPs in the galaxy.
• Allow study of structure & dynamics of the Halo
DRIFT Approach: Low-Pressure Negative Ion Drift TPC (NITPC).
-> Excellent BG rejection potential via range-ionization discrimination.
WIMP flux
Isotropic Maxwellian halo, v0=220kms-1
IDM2004
Directional sensitivity - 10-6 - 10-10pb
preliminary
perfect PSD with straggling
DRIFT I type with sense DRIFT I type
with no sense DRIFT II type
M-BTriaxial Osipkov-Merritt
technology
halo model
B. MorganA. Green
IDM2004
(UKDMC, Temple University, Occidental College)• 1m3 Dual Negative Ion DRIFT TPC• Back-to-back 0.5m3 DRIFT regions.• 1.4m3 vac vessel - 40 Torr CS2• Aim -> 10-6pb
Constructed 2000, Installed 2001/2Currently underground and taking data.
DRIFT I: - underground
Multi-module advanced detector incorporatingimprovements / upgrades from D-I.Target sensitivity (x 20) over DRIFT IInstallation: 1st stage Nov 04 → end 2005
DRIFT II: - 2004/5
The DRIFT Programme
Scale-up of DRIFT-IIIncorporating further technology upgrades.Towards design for 10-9pb
DRIFT III r&d: - 2006+
DRIFT-I @
Boulby
IDM2004
DRIFT-I Jan 2004Early data Analysis>1500hrs data acquired
Demonstrated:• Response to neutrons/alphas/gammas• Gamma rejection >106
• Fe55 calibration - stability• Early directionality demonstration• Towards neutron BG measurement
Cf252 Neutron
Fe55 GammaAlpha Sparks
IDM2004
Change software threshold25 DFNIPS 50 DFNIPS 75 DFNIPS
100 DFNIPS 150 DFNIPS 200 DFNIPS413 -> 0 reduction in gamma events
10% reduction in neutron events
ft3 test detector
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DI - Comparison with Cf-252
• 37.25 days of live time• 1.67 kg-days• 47 events• Rate = 28 events / kg / day• Unshielded!
prelim
IDM2004
Predictions - observations• U/Th levels measured in the DRIFT
lab using an unshielded Ge detector.
• Two neutron MCs agree onrate in detector.
• Detector MC used to predict detector response to software cuts and analysis procedure
• Predicted rate = 12.6 events / kg / day compared to observed rate = 28 events / kg / day
• Gamma simulation => rejection factor of >106
(if remaining events assumed gammas, else >105)
GEANT IV
IDM2004
DRIFT-I operationsOperational Issues 2002-2003
DAQ related:- Complex readout channel errors in slac-daq- Out of spec noise- Edge-alpha veto not fully operational - Difficulties with wire termination and
current limiting -> solved.- Misc DAQ, vessel & gas circulation issues
MWPC related:stable operation for 9-12 months but then..- Numerous ‘disconnected’ wires on MWPCs- Series of wire breakages- Difficulties with wire replacement -> solved
Jan 2004 - MWPC current stability issues Cause: Warping, HHV feed fatigue
IDM2004
DRIFT-I Since Jan 2004
MWPC current stability problem SOLVED!
Findings / modifications:MWPC Warping (up to 5mm across length).-> Counter-tension warping adjustments now installed. Warping now <1mmGas contamination - vessel leak around signal feedthrough plate.-> Leak now reduced from 0.1 to 0.02T/hr (acceptable contamination ~2%).
- New alpha veto hardware installed.- Shielding successfully erected
IDM2004
DRIFT-I neutron shieldingBeforeBefore
AfterAfter
8T polypropylene pellets inplywood jacket…- flexible, tolerant to floor movement- Fast Easy to install (without
XY crane).- 1/5th cost of wax or poly
sheet- Fast removable front door.
IDM2004
DRIFT-I
Shielding door OFF
(‘DRIFT-I Design, Installation & Operation’ J. Alner et al. ACCEPTED NIMA June 04)
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Import lessons for DRIFT-II
General:• No need for complex multi-wire daq - use grouping• Make robust, transportable, flexible, easy to handle & adaptable on-site.
Inner detector:• Vertical mounting of planes• Grid readout (3d)• Ensure adequate current limiting resistors.• Thicker wire field cage• Guard against warping in MWPCs & field cage.• Consider dirt accumulation and cleaning.• Consider accessibility and handling of MWPC planes. • Understand & control wire tensions.
Vessel / Gas Handling:• Improve gas circulation & collection (sealed operation)• Simpler vessel - use O rings and clamps for door• Consider alterative door system• Reduce leak rate -> contamination <
DRIFT-I Summary
IDM2004
DRIFT II
• Basic Design
Modular… n (3-4) × 1m3 fiducial vol, NITPCs• Back-to-back drift vols & dual MWPC readout• Vertical planes, Warp adjust strongback MWPCs• 3d track reconstruction (anode, grid and z-drift)(Improved resolution: ∆x = 2mm, ∆ y = 0.1mm,∆ z = 0.1mm)
• Lower noise DAQ (few keV S-recoil threshold)• Improved vessel design (<10-5T.L.s-1) .• Improved gas system (various pressure & gas mixtures)
• Aim
x 20 improvement in sensitivity of D-IScaleable for D-III
first steps to cheap modules
IDM2004
Front View
1.9m
1.5m
1.5m
1.00m
Skate plate
0.5m 0.5m0.135.m
0.09m
1.8m1.1
2m
1.22m
1.23m
0.135.m
0.14m
20cm widthSide walls forDoor hinge
E drift E drift
Design & Dimensions
(~170g target module @ 40 Torr, 680g @ 160 Torr, add Xe for higher mass)
Vessel (UKDM)MWPCs (Oxy)Field cage / Cathode (UKDM)Gas System (UNM)Grid DAQ (UKDM)Anode DAQ (Oxy)Boulby/installation (UKDM)Simulations (Boston)KK axions (Thessaloniki)Analysis (all)
~Who’s doing what?
IDM2004
4 DRIFT-II units:
= 4 × 2.5m+ 0.5 at end
+ 2.5m for gas sys & DAQ &end space
= 13m
DRIFT-II in JIF
5.06m
2.6m
2.5m
0.5m
Why Modular?
• Module comparisons - diagnostic array• Reduce risks of long down-time• Allows experimentation / development• Scale up = mass production issue. • etc…
• Smaller = easier to build (MPWCs, vessel)= easier to commission & install
• Constraints of available space
From Side
2.6m
= 2.26m
~2.2m
Hook height= 2.26m
Beam height= 2.7m
0.3m
0.15m
MWPC
5.06m
0.3m
- 2.15m
- 2.45m
3.24
m
IDM2004
MWPCsStrong-back MWPCs with warp adjustment
Anodes: 512 20µm wires, Grids 2×512 100µm wires (all 2mm pitch)
Wire winding @ Oxy
10 completed by Aug. 2004
1 produced every 3 days at the end
20 km wire wound
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
IDM2004
Grid & Anode DAQGRID: 12bit 5MHz sampling PCI ADCs.
Internal 64 fold grouping & Amptek pre-amplification - 8 channels per MWPC
X & Y alpha vetos read into GRID DAQ
ANODE: ASIC hit registers only (4*128)
Slow Control: 120 chan Agilent data acq unit.
1 DAQ PC per moduleAnode DAQ
Grid DAQ
tested on DRIFT I
IDM2004
Field Cage, Gas System
Ultra-torr sealed, flexible connection
Field cage: High purity Cu rod & Lucite frame
HHV Feed-through
Aim:1000V.cm-1
(50kV input)
IDM2004
Field-cages partially assembled (Aug 2004)
Field Cage
IDM2004
Vacuum VesselOut-sourced to Royal Welding (USA)& Wessington Cryogenics (UK)
(1.5m)3 int. dimensions8mm plate with support struts ~1.5 TLeak rate < 10-5 T.l/sSimple, functional, cost effective, mass-producible - and low background
~£12K per vessel.
IDM2004
Vessel construction
IDM2004
Module 1 vessel operating at Occidental Collage, US. Module 2 vessel under construction in UK.
Vessel construction
IDM2004
Successful acquisition of Fe-55 data in CS2 from 1st DRIFT-II module. Left: Fe-55 spectrum; right: typical Fe-55 event.
Initial tests of D-II hardware
Fe-55
IDM2004
Boulby JIF lab in 2005
JIF areanow
19.94m
5.76
Stub B
11.96m
5.93m
5.6
Stub A
Low BGLab
DRIFT
Area
26m (8 modules)10m 10m
LN Generator
2.01.5
>2.0m
ZEP - II ZEP - III
>2.0m
DRIFT Modules:1 - end 20043-4 - end 2005More? - 2005/6
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DRIFT in JIF
IDM2004
The Future: DRIFT III-IVAIM: reduce cost to ~£/$/20K per unit inc shielding
• Sensitivity potential: 10-8 pb over 1 yr (10-9 pb over 10yr), assuming zero B/G, 100+ unit array [see neutron background talks...]
• High-multiplicity array of 1.5 x 1.5 x 1.5 m3 vessels.• Coded-grouping on front-end electronics to reduce cost/complexity.• Sealed operation / high-spec vacuum vessels (leak-rate < 10-7 Torr.l/hr)• Alternative gases (CS2-Xe, CS2-CF4, …)
DRIFT III
DRIFT IV (more DRIFT III)• Effectively an expansion of DRIFT III up to ~1 ton target.• Sensitivity: 10-10 pb/yr.• e.g. sensitive to Sagittarius CDM stream[1]?• higher resolution readout technologies.• Other rare event searches: KK-axions, Universal Extra Dimensions …[1] K. Freese et al, Phys. Rev. Lett. 92 (2004), p. 111301.
IDM2004
DRIFT R&D
High resolutionreadouts
Also…• ‘Fiducialization’ - Cathode readout…• Alternative gases (or mixtures - eg. Xe)• Mass production engineering towards D-III → 10-
9pb
Simulations
(5 cm micromegas)
Concept by: Y. Giomataris etcCS2Fe55 5.9keV
spectrum
Halo Models & detector response
GEANT4 Simulation
(T.Lawson)
IDM2004
Other Readout- MICROMEGAS
prototype 25 x 25 cm2 CERN micromesh for testing of
Micromegas as an alternative readout technology.
can we mass produce sheets of GEM/micromegas+2d strip?
3M, TechEtch.....
IDM2004
Conclusions - DRIFT visionA directional signal - definitive, SEE THE WIMP HALO!
DRIFT technology - needs space, but:
no cryogenics neededno complex underground infrastructureno complex servicingno expensive target materialsno major problems (down time) with power outagesno levelling
modules potentially cheap (20K/Kg?)