ANGRA Neutrino Detector: Preliminary Design Main Concepts and Ideas (and some alternatives) Ernesto Kemp State University at Campinas – UNICAMP Gleb Wataghin Physics Institute – IFGW Cosmic Rays and Chronology Department – DRCC

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 m 3 Current SONGS detector

Target (1 m) 3 Steel 15 cm (6 sides) PMTs on 6 sides 20 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 m 3 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 Steel 15 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 m 3 Concept 2 Add independent  catcher

Target (1 m) 3 Steel 15 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 m 3 Concept 3 Add integrated  catcher

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? DetectorVolume (m 3 ) Singles rate (Hz) (%) Efficiency (per vol)   SONGS 27~10, Simple Inefficient Large High singles Concept 1 Steel Shield, no catcher 6~500~209 Simple Small Low  shower eff. Concept 2 Steel Shield, independent catcher 38~200~302 Good  shower eff. Use solid catcher? Catcher as fast neutron veto? Very large Many PMTs Concept 3 Steel Shield, integrated catcher 27 ~200 (2000 incl. catcher) ~303 Good  shower eff. Efficient use of PMTs Large Larger 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?