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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
Friday, August 28, 2009
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
Friday, August 28, 2009
M. Attisha
e,γχ,n
Friday, August 28, 2009
• 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
Friday, August 28, 2009
PMTs
Field Shaping
Rings
Gaseous Ar
Volume
Liquid Ar
Volume
Extraction and
Multiplication
Two-Phase Ar/Xe Drift Chamber
Friday, August 28, 2009
Energy Deposit
PMTs
Field Shaping
Rings
Gaseous Ar
Volume
Liquid Ar
Volume
Extraction and
Multiplication
Friday, August 28, 2009
Primary ScintillationPhotons (S1)
PMTs
Field Shaping
Rings
Gaseous Ar
Volume
Liquid Ar
Volume
Extraction and
Multiplication
Friday, August 28, 2009
Electrons SurvivingRecombination
Drift Towards AnodePMTs
Field Shaping
Rings
Gaseous Ar
Volume
Liquid Ar
Volume
Extraction and
Multiplication
Friday, August 28, 2009
Multiplication in GasSecondary Scintillation
Photons (S2)PMTs
Field Shaping
Rings
Gaseous Ar
Volume
Liquid Ar
Volume
Extraction and
Multiplication
Friday, August 28, 2009
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
Friday, August 28, 2009
First Dark Matter Results
Friday, August 28, 2009
Astropart. Phys. 28, 495 (2008)Zero Background Above 60 keVnr Threshold
First Dark Matter Results
Friday, August 28, 2009
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
Friday, August 28, 2009
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
Friday, August 28, 2009
• 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?
Friday, August 28, 2009
• 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?
Friday, August 28, 2009
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
Friday, August 28, 2009
Princeton Prototype Plant for Industrial Scale Production: Achieved 0.5 kg/day
Friday, August 28, 2009
Princeton Prototype Plant for Industrial Scale Production: Achieved 0.5 kg/day
Friday, August 28, 2009
Princeton Prototype Plant for Industrial Scale Production: Achieved 0.5 kg/day
Friday, August 28, 2009
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
Friday, August 28, 2009
• 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
Friday, August 28, 2009
A
A
736.60
1524.29
152.40
184.66
6.35
SECTION A-A SCALE 1 : 7
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
Friday, August 28, 2009
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
DO NOT SCALE DRAWING
20-kg Detector
Friday, August 28, 2009
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
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 2/26/09
External Detector AndRecirculation System Layout
SHEET 1 OF 1
External Layout
DO NOT SCALE DRAWING
20-kg Detector
Friday, August 28, 2009
DarkSide
UMass AmherstArizona State University
Augustana CollegeBlack Hills State University
FermilabUniversity of Houston
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
Friday, August 28, 2009
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%
Friday, August 28, 2009
Top Plate (3” QUPID x 127)
1 m
Friday, August 28, 2009
Bottom Plate (8” PMT x 19)
1 m
Friday, August 28, 2009
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
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
DIMENSIONS ARE IN CMTOLERANCES:FRACTIONALANGULAR: MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL
INTERPRET GEOMETRICTOLERANCING PER:
MATERIAL
FINISH
DRAWN
CHECKED
ENG APPR.
MFG APPR.
Q.A.
COMMENTS:
Any Questions Call Tristen Hohman:
Office # 6092586761
Cell # 9083990783
DATENAME Drawn By: Tristen Hohman
TITLE:
SIZE
BDWG. NO. REV
WEIGHT: SCALE: 1:50
UNLESS OTHERWISE SPECIFIED:
1
TH 8/21/09
Conceptual Layout of 500kg LArDetector and Cryostat
SHEET 1 OF 1
500kg detector
DO NOT SCALE DRAWING
Friday, August 28, 2009
A
A
500.74
370.23
SECTION A-A SCALE 1 : 57
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
Drawn By: Tristen Hohman
TH 8/21/09
Shielding ConstructionFor
500 kg LAr Detector
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 CENTIMETERSTOLERANCES:FRACTIONALANGULAR: MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL
DO NOT SCALE DRAWING
FINISH
MATERIAL
REV.
ADWG. NO.SIZE
SCALE:1:128
Friday, August 28, 2009
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
Drawn By: Tristen Hohman
TH 8/21/09
Shielding ConstructionFor
500 kg LAr Detector
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 CENTIMETERSTOLERANCES:FRACTIONALANGULAR: MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL
DO NOT SCALE DRAWING
FINISH
MATERIAL
REV.
ADWG. NO.SIZE
SCALE:1:128
Friday, August 28, 2009
!"#$%&'((%)*+,-
./0((%1+23405%1+5(4346437
89 89: 89; 89<
89=<9
89=<8
89=<:
89=<;
89=<<
89=<>
89=<?
89=<@
89=<A
./0((%1+23405%)2&
: -
B'/C14D+.B#1""%*+%.0&E45+DFGHIH=89%:99@J%KG$L"H="""!MN$=;O:%CP%Q>>%C+,R
Friday, August 28, 2009
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.
Friday, August 28, 2009
MAX - Multi-ton Argon & Xenon
WESTFÄLISCHE
WILHELMS-UNIVERSITÄT
MÜNSTER
UMass AmherstArizona State University
Augustana CollegeBlack Hills State University
Coimbra UniversityColumbia University
FermilabUniversity of Houston
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
Friday, August 28, 2009
!"#$%&'((%)*+,-
./0%1$2%345%6789:0%';6+0%;<=>%'8=%?@6(A%B+%1$2%%34%678C:0%%';6+0%;<=>%'8=%?@6(A2.#D""%*+%27&E<8+=BFGHG94I%5IIJ!/K$9L>5%MN%3OO%M+,A
207((%D+?6<78%D+8(<6<P<6:
4I 4I5 4IL 4IQ
4I9QI
4I9Q4
4I9Q5
4I9QL
4I9QQ
4I9QO
4I9QR
4I9QJ
4I9QS
207((%D+?6<78%)?&
5 -
Friday, August 28, 2009
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.
Friday, August 28, 2009