darkside a two-phase depleted argon tpcsnolab2009.snolab.ca/snolab-workshop-09/galibiati-dark... ·...

DarkSide-

a Two-Phase Depleted Argon

TPC

Cristiano GalbiatiPrinceton University

for the DarkSide Collaboration

SNOLAB Workshop 2009Lively, ON

Aug 28, 2009

Friday, August 28, 2009

DarkSide

UMass AmherstArizona State University

Augustana CollegeBlack Hills State University

FermilabUniversity of Houston

University of Notre DamePrinceton UniversityTemple University

UCLA


Past and Current Efforts• WARP 3.2-kg• funded by INFN, construction at Pavia, operation at

LNGS with participation from Princeton• completed 2006 - first and so far only dark matter

result with argon - Astropart. Phys. 28, 495 (2008)

• WARP 140-kg [NSF PHY-0603376]• funding from INFN and NSF (through Princeton)• installation completed; commissioning ongoing

• Investigation of depleted argon from underground wells [PHY-0704220] [Princeton U. Seed Fund]• demonstrated availability of large quantity of

depleted argon, 39Ar reduced by >25Friday, August 28, 2009

Short- and Long-Term Future• DUSEL (2013 and beyond) [NSF PHY-0919363]• MAX - Multi-ton Argon and Xenon• 20 institutions, 5-t DAr and 2.5-t Xe TPCs• NSF announced intention to fund S4 proposal

• Depleted Argon Production [NSF PHY-0811186]• funded from NSF through Princeton• 2 kg/day, depletion >25, by end of 2009

• DarkSide Detector (2009-2012)• first depleted argon TPC• demonstration of key features• competitive dark matter search


M. Attisha

e,γχ,n


• Pulse shape discrimination of primary scintillation (S1) based on the difference in decay times between singlet (≈ 7 ns) and triplet (1.6 µs) components of the emitted UV light

Minimum ionizing: triplet/singlet ~ 3/1Nuclear recoils: triplet/singlet ~ 1/3Theoretical Identification Power exceeds 108 for > 60 photoelectrons (Boulay & Hime 2004)

• Difference in ratio of the prompt scintillation (S1) to the drift time-delayed ionization (S2)

• Precise determination of events location in 3D

• Up-front reduction os large 39Ar cosmogenic rate

Discrimination in Depleted Argon TPC


PMTs

Field Shaping

Rings

Gaseous Ar

Volume

Liquid Ar

Volume

Extraction and

Multiplication

Two-Phase Ar/Xe Drift Chamber


Energy Deposit

PMTs

Field Shaping

Rings

Gaseous Ar

Volume

Liquid Ar

Volume

Extraction and

Multiplication


Primary ScintillationPhotons (S1)

PMTs

Field Shaping

Rings

Gaseous Ar

Volume

Liquid Ar

Volume

Extraction and

Multiplication


Electrons SurvivingRecombination

Drift Towards AnodePMTs

Field Shaping

Rings

Gaseous Ar

Volume

Liquid Ar

Volume

Extraction and

Multiplication


Multiplication in GasSecondary Scintillation

Photons (S2)PMTs

Field Shaping

Rings

Gaseous Ar

Volume

Liquid Ar

Volume

Extraction and

Multiplication


Argon recoil(B) S2S1

S1

Electron(A) S2S1

S1

Drift time

Events are characterized by:the ratio S2/S1 between the primary (S1) and secondary (S2)the rising time of the S1 signal

Minimum ionizing particles: high S2/S1 ratio (~100) and by slow S1 signal

Ar recoils: low (≤10) S2/S1 ratio and fast S1 signal

First Two Discrimination Methods


First Dark Matter Results


Astropart. Phys. 28, 495 (2008)Zero Background Above 60 keVnr Threshold

First Dark Matter Results


The WARP 140-kg detector, currently under commissioning at LNGS

140 kg active target, to reach into 5x10-45 cm2 and cover critical part of SUSY

parameter space

Complete neutron shield!

4π active neutron veto (9 tons Liquid Argon, 300 PMTs)

Active control on nuclide-recoil background, owing to unique feature (LAr

active veto)

3D Event localization and definition of fiducial volume for surface background

rejection

Detector designed for positive confirmation of a possible WIMP discovery

Cryostat designed to allocate a possible 1400 kg detector

WARP 140-kg Detector

Passive neutron and gamma shield

Active Veto100 liters Chamber


101 102 103 104

Cross Section [pbarn]

(normalized to nucleon)

10-4

10-9

10-14

10-18

WIMP Mass [Gev/c2]

Excluded by Direct

Detection

R. Schnee

Current Limit

100 kg Ge/Xe - 400 kg Ar

5 t Ge/Xe - 20 t Ar

250 t Ge/Xe - 1 kt Ar

SUSY Exploration


• Radioactive 39Ar produced by cosmic rays in atmosphere

• beta decays, Q = 565 keV, t1/2 = 269 years

• In atmospheric argon:

• 39Ar/Ar ratio 8×10-16

• specific activity 1 Bq/kq

• Limits size (and sensitivity) of argon detectors to 500-1000 kg due to 39Ar events pile-up

Why is underground argon desirable?


• 39Ar-depleted argon available via centrifugation or thermal diffusion, but expensive at the ton scale!

• 39Ar production by cosmic rays strongly suppressed underground

• Motivated by success in Borexino• Low background from 14C crucial for observation

of low energy neutrinos with organic liquid scintillators.

• Hydrocarbons in deep underground reservoirs results in low cosmogenic 14C

Why is underground argon desirable?


Sources Viable for Large Scale Production

National Helium Reserve

Doe Canyon Complex

39Ar <50 mBq/kg <40 mBq/kg

Depletion >20 >25

Production capacity 30 tons/yr >10 tons/yr


Princeton Prototype Plant for Industrial Scale Production: Achieved 0.5 kg/day


Purification by cryogenic distillation

Cryogenic distillation column designed at

Princeton, to be commissioned

Summer-Fall 2009

Performance:purification of 20 kg

per day of argon to 4-5 nines of purity

26.00

186.38114.00

34.13

36.00

A

A

129.00 127.00

24.00

62.50

62.50

23.75

10.381.00

19.7532.00

SECTION A-A SCALE 1 : 24

Bottom Dewar

Reboiler Volume

Lift Points

Packing Material

Stripping Column

Vacuum Walled Section

Top Vacuum Walled SectionCondensing VolumeHeater Blocks

2x AL600 Cryocoolers

Two Of The Three Vacuum WalledSections Will Be Supplied Along With The 2 AL600 Cryocoolers AndThe Three Heater Blocks.

WEIGHT:

3cryostripping column revised 3

Drawn By: Tristen Hohman

TH 4/13/09

Main View of CryostrippingColumn

PROPRIETARY AND CONFIDENTIALTHE INFORMATION CONTAINED IN THISDRAWING IS THE SOLE PROPERTY OFPRINCETON UNIVERSITY. ANY REPRODUCTION IN PART OR AS A WHOLEWITHOUT THE WRITTEN PERMISSION OFPRINCETON UNIVERSITY IS PROHIBITED.

COMMENTS:

Any Questions Call Tristen Hohman:

Office # - 609-258-6761

Cell # -908-399-0783SHEET 1 OF 1

Q.A.

MFG APPR.

ENG APPR.

CHECKED

DRAWN

DATENAMEDIMENSIONS ARE IN INCHESTOLERANCES:FRACTIONALANGULAR: MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL

DO NOT SCALE DRAWING

FINISH

MATERIAL Mostly 304 Stainless Steel

REV.

ADWG. NO.SIZE

SCALE:1:48


• R&D completed this summer with deployment of cryogenic distillation

• First stage upgrade to 2-kg per day in 2009

• Second stage upgrade to 20-kg per day in 2010

• Production costs below $400/kg

• Includes capital and consumables

Depleted Ar Prodution Outlook


A

A

736.60

1524.29

152.40

184.66

6.35


Level Sensor Array

Level Sensor (5)Spring LoadedPositioning Ring

Condensing Volume

Fill Line

Internal Detector

Support Structure

PT-90 Coldhead

Heater BlockLevel Probe Positions(From top flange)

1 - 454.12 mm

2 - 477.52 mm

3 - 774.70 mm

4 - 944.88 mm

5 - 1231.9 mm

D

C

B

AA

B

C

D

1245678

8 7 6 5 4 3 2 1

3

64 kg LAr6.7 kg active mass

Light Yield: 5 pe/keV

6-kg Detector


118.46

40

13.34

Cartridge Heater

Reboiling Arm

Flexible Metal Bellows

Level Sensor Array14 Pt1000 Sensors

8" PMT

InnerVolumeLAr Line

PT90 Coldhead

Inner Volume GArReturn Port

Electrical Feedthrough ForCartridge Heater

Dual Volume CondensingChambers

Nylon Rod For Support Cage

Main NylonSupport Rods

7 3" PMT's

Large Diameter HalfNipple For DewarExtension

20.20

A

Inner Detector GAr Fill LineBuffer GAr Fill Li ne

Buffer Region LAr Fill Line

All Steel Fill Lines Must Incorporate Flexible SectionsTo Alleviate Any Stresses On The Inner Detector Due to Contraction On Cooling.

Inner Detector LAr Level

Approximate Buffer LAr Level

168.24

136.21

47.63

DETAIL A SCALE 1 : 2

Steel To Acrylic FlangeWith Teflon Gasket

GAr Region RecirculationLine. (2cm Inner Gar Region)

ALL UNITS ARE INCENTIMETERS

D

C

B

AA

B

C

D

12345678

8 7 6 5 4 3 2 1

THE INFORMATION CONTAINED IN THISDRAWING IS THE SOLE PROPERTY OFPRINCETON UNIVERSITY. ANY REPRODUCTION IN PART OR AS A WHOLEWITHOUT THE WRITTEN PERMISSION OFPRINCETON UNIVERSITY IS PROHIBITED.

PROPRIETARY AND CONFIDENTIAL

NEXT ASSY USED ON

APPLICATION

DIMENSIONS ARE IN CENTIMETERSTOLERANCES:FRACTIONALANGULAR: MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL

INTERPRET GEOMETRICTOLERANCING PER:

MATERIAL

FINISH

DRAWN

CHECKED

ENG APPR.

MFG APPR.

Q.A.

COMMENTS:

DATENAMEDrawn By: Tristen Hohman

TITLE:

SIZE

BDWG. NO. REV

WEIGHT: SCALE: 1:16

UNLESS OTHERWISE SPECIFIED:

1

TH 2/26/2009

Layout Of Internal DetectorAnd Recirculation Lines

SHEET 1 OF 1

Internal Layout


20-kg Detector


V1

V2

V3

V4

V5

V6

V7

V8

V9

V10

V11

PV1

PV2

PV3

PurifierFlowmeter

Pump

Sampling Port 1

Sampling Port 2

Filling Port

Ar CondensingVolumes

Fermilab Dewar

4-Pin 2kV High Voltage FeedthroughFor PMT's

4-Pin 2kV High Voltage FeedthroughFor PMT's

Feedthrough For Gas Region Recirculation

Feedthrough For Gas Region Recirculation

Feedthrough For Buffer Ar Insertion

Feedthrough For Active Ar Insertion

Vacuum Port

32-Pin Component FeedthroughFor PMT Signal And Grounds

50kV High Voltage FeedthroughFor Cathode

15kV High Voltage Feedthrough For Anode, Grid, And First Shaping Ring32-Pin Component Feedthrough ForLevel Sensors 8-Pin Electrical Feedthrough For Active Ar Reboiling Heater

Feedthrough for Active ArRecirculation

D

C

B

AA

B

C

D

12345678

8 7 6 5 4 3 2 1



NEXT ASSY USED ON

APPLICATION

DIMENSIONS ARE IN CENTIMETERSTOLERANCES:FRACTIONALANGULAR: MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL


MATERIAL

FINISH

DRAWN

CHECKED

ENG APPR.

MFG APPR.

Q.A.

COMMENTS:

DATENAMEDrawn By: Tristen Hohman

TITLE:

SIZE

BDWG. NO. REV

WEIGHT: SCALE: 1:16


1

TH 2/26/09

External Detector AndRecirculation System Layout

SHEET 1 OF 1

External Layout


20-kg Detector


DarkSide




University of Notre DamePrinceton UniversityTemple University

UCLAFriday, August 28, 2009

DarkSide: First DAr TPC

• Key features• low background from 39Ar (aim at 1 mBq/kg)• breakthrough photosensors• QUPIDs, <1 mBq/unit• Much increased QE and CE at 86K

• low background from construction materials• Ti cryostat• sealed PMMA vessel for DAr• gas-, liquid-based purification systems (Fermilab)

• Competitive dark matter search• Discovery potential ~5×10-46 cm2


QUPIDs

0.1

1

10

100

1000

10000

-200 -175 -150 -125 -100 -75 -50 -25 0 25

Cu

rren

t w

ith

-5%

No

n-L

ineari

ty (

nA

)

Temperature (C)

Bialkali-LT vs. Standard Bialkali

DC Linearity

BIALKALI-LT

R8778

R8520

!"#$%& '(%$%&

BIALKALI-LT

R8520

R8778

0

5

10

15

20

25

30

35

40

150 200 250 300 350 400 450 500 550 600 650 700

Quantum

Efficiency [%

]

Wavelength [nm]

R3998 with Quartz/Borosilicate Window Spectral Response Characteristics

Type: R3998 with Quartz Serial No.: BA193 SK: 160uA/lm SKb: 12.2 Q.E. at 175nm: 29% Q.E. at 420nm: 29%

small discrepancy due to the different test setup

Type: R3998 with Borosilicate Serial No.: BA194 SK: 160uA/lm SKb: 12.2 Q.E. at 420nm: 33%


Top Plate (3” QUPID x 127)

1 m


Bottom Plate (8” PMT x 19)

1 m


229.

38

172

A

A

125

14

85.5

05

97

92.20

128

19.7

9

SECTION AA SCALE 1 : 12

500 kg LAr Volume

GAr Layer

127 3" PMT's Top

19 8" PMT's Bottom

All Units Are In Centimeters

D

C

B

AA

B

C

D

12345678

8 7 6 5 4 3 2 1



DIMENSIONS ARE IN CMTOLERANCES:FRACTIONALANGULAR: MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL


MATERIAL

FINISH

DRAWN

CHECKED

ENG APPR.

MFG APPR.

Q.A.

COMMENTS:


Office # 6092586761

Cell # 9083990783

DATENAME Drawn By: Tristen Hohman

TITLE:

SIZE

BDWG. NO. REV

WEIGHT: SCALE: 1:50


1

TH 8/21/09

Conceptual Layout of 500kg LArDetector and Cryostat

SHEET 1 OF 1

500kg detector



A

A

500.74

370.23


30 cm HDPE

5 cm Steel

20 cm Lead

Cart On Rails To Open Door

Steel I-Beam Support Frame

B

B

914.40

381

304.80

182.88

172

229.38

SECTION B-B SCALE 1 : 57

WEIGHT:

1500kg detector with shielding


TH 8/21/09

Shielding ConstructionFor

500 kg LAr Detector


COMMENTS:


Office # - 609-258-6761

Cell # - 908-399-0783SHEET 1 OF 1

Q.A.

MFG APPR.

ENG APPR.

CHECKED

DRAWN

DATENAMEDIMENSIONS ARE IN CENTIMETERSTOLERANCES:FRACTIONALANGULAR: MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL


FINISH

MATERIAL

REV.

ADWG. NO.SIZE

SCALE:1:128


370.23

500.74

High Load Cart For Door Opening

Steel Support Frame

20 cm Lead Shielding

5 cm Steel Shielding

30 cm HDPE Shielding

WEIGHT:

1500kg detector with shielding open


TH 8/21/09

Shielding ConstructionFor

500 kg LAr Detector


COMMENTS:


Office # - 609-258-6761

Cell # - 908-399-0783SHEET 1 OF 1

Q.A.

MFG APPR.

ENG APPR.

CHECKED

DRAWN

DATENAMEDIMENSIONS ARE IN CENTIMETERSTOLERANCES:FRACTIONALANGULAR: MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL


FINISH

MATERIAL

REV.

ADWG. NO.SIZE

SCALE:1:128


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./0((%1+23405%1+5(4346437

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: -

B'/C14D+.B#1""%*+%.0&E45+DFGHIH=89%:99@J%KG$L"H="""!MN$=;O:%CP%Q>>%C+,R


Milestones• 6-kg Detector• completed

• 20-kg Detector• to be completed in 2009• underground operation Spring 2010

• 500-kg Detector• proposal fall 2009• operation 2012

• Depleted Argon Production• 2 kg/day demonstrated by Feb 2010• schedule for 20 kg/day t.b.d.


MAX - Multi-ton Argon & Xenon

WESTFÄLISCHE

WILHELMS-UNIVERSITÄT

MÜNSTER



Coimbra UniversityColumbia University


INAFLNGS

MITUniversity of Münster

University of Notre DamePrinceton University

Rice UniversityTemple University

UCLAUnivesity of VirginiaWaseda University

University of ZürichFriday, August 28, 2009

5 ton DAr TPC 2 ton Xe TPC


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The End

Like the jelly beans in this jar, the Universe is mostly dark: 96 percent consists

of dark energy (about 70%) and dark matter

(about 26%). Only about four percent (the same proportion as the lightly colored jelly beans) of

the Universe - including the stars, planets and us -

is made of familiar atomic matter.


darkside a two-phase depleted argon tpcsnolab2009.snolab.ca/snolab-workshop-09/galibiati-dark... ·...

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