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

IDM2004

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)

IDM2004

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

IDM2004

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?)