ANGRA Neutrino Detector:

Preliminary Design

Main Concepts and Ideas (and some alternatives)

Ernesto Kemp

State University at Campinas – UNICAMPGleb Wataghin Physics Institute – IFGW

Cosmic Rays and Chronology Department – DRCC

kemp@ifi.unicamp.br

Topics

The Detector Set (VND, ND and FD): clear purposes and goals

Main Concepts Geometry PMTs distribution Electronics Optics Mechanics Operation Deployment Strategies

The Detector Set: VND, ND and FD

VND: Test and Prototype for Theta-13 ND and FD Safeguard Tools development

ND: VND in a bigger scale (?)

FD: VND in a bigger scale and

different geometry (sphere) ?

As long as detectors grow in side their concepts can diverge to reach optimal configuration.

How should we get far from “identical” ND&FD concept ?

Small Term

Medium to Long Term

Geometry: guide lines

Monolitic 3-Volume Design Cilyndrical Shape

Alternatives: should be adopted under consistent criteria

Lab tests Simulation

Geometry Alternatives

Why ? Compact design to save space

operational conditions Cost reduction

3V vs. 2V different designs 2005 California discussion Buffer + Catcher Integration

2005 California Round:Working Concepts for a very near detector (Slides © ® by Nathaniel Bowden – SANDIA)

Preliminary discussions involving SNL/LLNL, ANL, Saclay and Brazil

Goals Work towards a compact detector design for deployment at

SONGS, Chooz?, Angra?... Determine tradeoffs for safeguards vs theta13

efficiency vs systematic error, energy resolution size, cost, etc

Have developed several concepts to study in more detail

Target (1 m)3

Target PMTs/air

Water Shielding ~80 cm

Plastic scintillator veto (3 cm)

Target -> (PMT + Air) -> Shield -> Veto radius: 50 cm +20 cm + 80 cm + 3 cm ~ 150 cm volume ~ (300 cm)3 ~ 27 m3

Current SONGS detector

Target (1 m)3

Steel 15 cm(6 sides)

PMTs on 6 sides20 cm air gap

A) Target -> (PMT + Air) -> Shield -> Veto 50 cm +20 cm +15 cm +3 cm = 88 cm volume = (176 cm)3 = 5.5 m3

Plastic scintillator veto (3 cm), 6 sides

Center to edge distance = 88 cm

Concept 1

Replace water with much denser shield

Target (1 m)3

Steel15 cm

Target PMTs/air on 20 cm

Plastic scintillator gamma catcher 60 cm

Veto PMTs/air 20 cm

Plastic scintillator veto (3 cm)

B) Target -> (PMT + Air) -> GammaCatcher -> (PMT + Air) -> Shield -> Veto 50 cm +20 cm + 60 cm +20 cm + 15 cm + 3 cm = 168 cm volume = (336 cm)3 = 38 m3

Concept 2 Add independent catcher

Target (1 m)3

Steel15 cm

Scintillator gamma catcher 60 cm

Veto PMTs/air 20 cm

Plastic scintillator veto (3 cm)

C) Target -> GammaCatcher -> (PMT + Air) -> Shield -> Veto 50 cm + 60 cm +20 cm + 15 cm + 3 cm = 148 cm volume = (296 cm)3= 26 m3

Concept 3 Add integrated catcher

1.00E-01

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

1.00E+07

1.00E+08

0.00 50.00 100.00 150.00 200.00

SONGS

No Catcher

IndependentCatcher

IntegratedCatcher

Radius, cm

Hz,

to

tal

Lower rates

target

Would likely add a layer of neutron moderator in addition…

Comparison

Questions: Better for safeguards to replace catcher with active volume? Minimum feasible overburden? Minimum systematic error to be useful for helping theta13?

Detector Volume (m3)

Singles rate (Hz) (%)

Efficiency (per vol)

SONGS

27 ~10,000 10 1

Simple InefficientLargeHigh singles

Concept 1

Steel Shield,

no catcher6 ~500 ~20 9

SimpleSmall

Low shower eff.

Concept 2

Steel Shield,

independent

catcher

38 ~200 ~30 2

Good shower eff.Use solid catcher?Catcher as fast neutron veto?

Very largeMany PMTs

Concept 3

Steel Shield,

integrated

catcher

27

~200

(2000 incl. catcher)

~30 3

Good shower eff.Efficient use of PMTs

LargeLarger active area for singles

Buffer+Catcher Integration

Concept: have both in a more compact way

B+C

T

By weighting and imposing spatial cuts:

selection between catcher and buffer events

Needs at least 10 cm of spatial resolution

Questions:

Does it work well in a small detector?

PMTs (detailled discussion on Laudo´s talk) Spatial Distribution

Question: do we really need the cap´s PMTs? Assembling method

External PMT easy maintenance optical window interfaced

reduce light collection efficiency Potential liquid leakage

lots of holles in the external container Partial PMT Immersion

neck outside the detection volume No optical interface , but the holles are still there

Full PMT immersion Electronics

Custommized Front-End integration and sealling:Vendor vs. Angra team ?

PMTs alternative orientation

Tank Center

Virtual

Spheres

Tank wall

Electronics (also in Laudo´s talk)

Custommized Front-End: Integration with PMTs HV divider Pre-Amplifier and shaper Signal Driver

Required by cable lengths ! Continuous DAQ Basic Trigger Levels implemented on-board

Event tagging and selection

Optics: matching properties among volumes

Volumes separation: acrylic vessels

Mechanical and chemical properties have to be studied

T

C

B

fotons

pmt

Mechanics

Volumes structure Cable paths Calibration tools : lasers, leds

Internal vs. External access PMT structure

All under preliminary discussions

Operation

VND First step: LVD tank and Prototype

“container” laboratory Remote + Minimal Local Intervention

Deployment Strategy

We have to make a smooth and very well planned transition from external measurements (LVD tank and Prototype) Underground measurements (Prototype and VND)

Reduce at maximum the impact and support needs from Eletronuclear people

Project modifications is slow and difficult

Present configuration :

Hybrid of DC technology at SONGS scale !

Future:

Well defined tasks and teams to efficient progress

Preliminary Definitions: At this WorkShop?