SNOLab-Majarana Aug. ‘05 Overview: Phased approach and scientific reach Funding and schedule ...

SNOLab-Majarana Aug. ‘05

Overview:

Phased approach and scientific reach

Funding and schedule

Experimental layout and detailed infrastructure needs

Change in strategy and schedule given LAr option

Majarana double beta decay program

Peter Doe, on behalf of the Majorana collaboration


Phased approach and scientific reach

Scalable 3 phases:M180… 180 kg, 86% enriched 76Ge,

60 kg 120 kg 180 kg

“conventional” technology

m≥ 120 meV (degenerate

hierarchy)

M500/M1000… 500-1000 kg,

LAr/LN2 collaboration with GERDA?

m≥ 50 meV (inverted hierarchy)

MX000… Technology unknown?

m≥ 10 meV (normal hierarchy)


Funding

Expect NuSAG response at end of August

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture. QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.?Possibility of early activity U/G in FY-06

Funding from Majorana institutional support

No federal funding before FY-07


Year 0 Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Year 11

Proposal/CD-0 Package

CD-0/Approve Mission Need

R&D module

Conceptual Design

Site Selection

CD-1/Approve Preliminary Baseline Range

Preliminary Design (PED)

CD-2/3a/Approve Baseline/Long-Lead Procurement

3a: Prepare and Ship Ge

Site Preparation

CD-3 Start Construction

Receive Ge

Fabricate Detectors

Electroforming Production Cryostats

Assemble Experimental Apparatus/Shielding

Assemble Detectors into Cryostat/Shield

Pre-Operational Testing

CD-4/Start of Operations

Full Detector Operations

Decommissioning

R&D Module

EnrichedGe

1st 60 kgrunning

2nd 60 kgrunning

3rd 60 kgrunning

M180 Operating Phase

Construction

2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

Schedule


Majorana modular approach• 57 crystal module (60 kg)

– Conventional vacuum cryostat made with electroformed Cu.– Three-crystal stack are individually removable.

Cold Plate

1.1 kg Crystal

ThermalShroud

Vacuum jacket

Cold Finger

Bottom Closure 1 of 19 crystal stacks

CapCap

Tube (0.007” wall)

Tube (0.007” wall)

Ge(62mm x 70 mm)

Ge(62mm x 70 mm)

Tray(Plastic, Si, etc)

Tray(Plastic, Si, etc)


Majorana shield - conceptual design– Allows modular deployment, early operation– contains up to eight 57-crystal modules

(M180 populates 3 of the 8 modules)– four independent, sliding units– 40 cm bulk Pb, 10 cm ultra-low background shield– active 4 veto detector

Top view

57 Detector Module

Veto Shield

Sliding Monolith

LN Dewar

Inner Shield


Experimental layout/infrastructure - M180

Three areas of underground activity:1. Fabrication

Electroforming copper parts

2. Assembly

Putting it together

Making it work

3. Data taking - staged by module

60 kg

120 kg

180 kg


Layout - Fabrication areas

Dimensions in meters


Layout - Detector area

Dimensions in meters


2 crystal thermal shroud, 250 m wall thickness

Low background electroformed copper

Component Mass

Inner mount 2 kg

Cryostat 38 kg

Copper shield 310 kg

Small parts 1 gm/crystal

Mass, M180 copper components

Electroformed cold finger and signal wires for MEGA


• Semiconductor-grade acids• Copper sulfate purified by

recrystallization• Baths circulated with continuous

microfiltration to remove oxides and precipitates

• Continuous barium scavenge removes radium

• Cover gas in plating tanks reduces oxide formation

• Periodic surface machining during production minimizes dendritic growth

• H2O2 cleaning, citric acid passivation

Electroforming copper - key elements

Electroforming copper

A B

C

A B

C

CuSO4

Current density ~ 40mA/cm2

Plating rate ~ 0.05 mm/hr

232Th<8Bq/kg


Electroforming copper - Infrastructure

• HEPA-filtered air supply• Radon-scrubbed air for lowest-level

work• Fume extractor for etching• Flammable and hazardous gas

sensors• Radon-proof storage lockers with

purge gas and vacuum capability• Etching and acid storage• Spill containment lining• Milli-Q water system w/DI supply

water• Air-lock entry, washable walls• Air-conditioning to ~ 20 C• 10-6 Torr dry vacuum system

Cold plate for the MEGA feasibility study at WIPP, NM.


Location Space (m)

Power (kW)

Air Quality Occupancy(People/shift)

control room 5x4x3 30 (ups) regular lab 2

detector 5x5x3 2 (ups) class 100, radon free 0-2

assembly 5x5x3 8 (ups) class 100, radon free 0-4 (2 shifts)

entry 4x4x3 1 HEPA -

storage (dirty) 4x4x3 1 regular lab -

storage (clean) 4x4x3 1 class 100, radon free -

electroforming 4x10x3 40 class 2,000, radon free 0-4 (2 shifts)

shop 4x10x3 24 class 2,000, radon free 0-4 (2 shifts)

entry 4x10x3 1 HEPA -

Total 214 m3 108 9

Infrastructure (continued)


M180 - Special considerations

•Cryogens (1000 liters)•Waste gasses (electroforming, etching)•Acids (electroforming)•Solvents (alcohol, acetone…)

•Oxidizers (dilute H2O2 cleaner)

•Lead (shielding)•Flammable plastics (veto)•Compressed gasses

•Radon-free inert cover gasses (LN2?)

•Radioactive sources


LAr option - strategy change and schedule

• 2 year LArGe R&D - Crystal, light stability in Lar- Detector Monte Carlo studies- Detector design- Engineering design

•Estimate 3m Ø cryogenic vessel (~20 ton LAr)•Requires underground fabrication of dewar ( schedule)•Less electroformed copper parts ( schedule)•Would not change enrichment schedule•Would not change staging plan (~60120180 kg)•Would need higher overhead clearance (≥8 m ?)

Decision


Summary

•Majorana is modular, 60120180 500X,000 kg

•M180 employs demonstrated, “conventional” technology

•Material purity is critical, but achievable

•Significant underground fabrication, assembly

•Optimistically, enrichment late 2007, first data 2009/10

•LAr option being investigated, little schedule impact(?)



Electroforming numbers

Bath size:Cryostat 40 cm high x 40 cm Tank 50cm x 75cm x 50cm 225 liters

x 8 tanks 1800 liters

Plating time:Cryostat 3mm / 0.05 mm hr-1 = 60 hr

@50% efficiency, 12 hr/day = 10 days (2 weeks)

Bath power:Cryostat Area = x 202 x 40 = 5030 cm2

power = 5030 cm2 x 40 mA cm-2 2 kAAssume 4 kW/bath 32 kW total


Cu parts count

Part type module M180 +30% Bath-weeks

cold finger 1 3 4 8

cold plate 1 3 4 8

caps 19 57 171 6

cryostat top 1 3 4 8

cryostat bottom 1 3 4 8

cryostat wall 1 3 4 8

thermal shroud 1 3 4 4

suspension tube 57 171 228 4

54 bath weeks, 100% contingency, 8 baths 4 months electroforming @ 2 shifts/day, 5 days/week


Plating Bath Process Parameters Plating Bath Process Parameters

Constituent Concentration

CuSO4 188 g/l

H2SO4 75 g/l

HCl 30 mg/l

Thiourea 3 mg/l

CoSO4 1 mg/l

BaSo4 ~1 mg/l

Plating is done onto polished, cleaned, stainless steel mandrels in the shape of the desired parts

Current density is ~40 mA/cm2

Plating rate is ~0.05 mm/hBaSO4 collects in the micro-

filtration stage and acts as radium scavenge

CoSO4 was added as a holdback carrier for the cosmogenic 56,57,58,60Co present in the starting copper

HCl and Thiourea affect copper crystal nucleation and grain size



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SNOLab-Majarana Aug. ‘05 Overview: Phased approach and scientific reach Funding and schedule ...

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