SINP MSUSINP MSU, , July 7, July 7, 201 20122

I.Belolaptikov behalf BAIKAL I.Belolaptikov behalf BAIKAL collaborationcollaboration

Depth – 1360 m with flat bed at distance > 3 km from the shore allows > 250 km3 instrumented volume !

>250 km3

Winterexpedition

Summer expedition

Day temperature

Site properties

Strong ice cover during ~2 months:- Telescope installation, maintenance, upgrade and rearrangement

- Installation & test of a new equipment

- All connections are done on dry

- Fast shore cable installation (3-4 days)

Water optical properties:- Absorption length – 22-24 m

- Scattering length – 30-50 m

- Moderately low background in fresh water

Water properties allow detection of all flavor neutrinos with high direction-energy resolution!

Site properties

ice slot

cable

tractor with ice cutter

cable layer

Shore cable deployment

March 2011

NT200: 8 strings (192 OMs)Height x = 70m x 40m, Vinst=105m3

Effective area: 1 TeV~2000m² Eff. shower volume: 10 TeV~ 0.2 Mton

Quasar photodetect

or (=37cm)

NT200+ = NT200 + 3 outer strings (192+36 OMs)Height x = 210m x 200m, Vinst = 5106m3

Eff. shower volume: 104 TeV ~ 10 Mton

1998 - NT2002005 - NT200+

~ 3.6 km to shore, 1070 m depth

Gigaton Volume Detector (GVD) in Lake BaikalR&D status

Objectives: - km3-scale 3D-array of photodetectors - flexible structure allowing an upgrade and/or a rearrangement of the main building blocks (clusters) - high sensitivity and resolution of neutrino energy, direction and flavor content

Central Physics Goals: - Investigate Galactic and extragalactic neutrino “point sources” in energy range > few TeV - Diffuse neutrino flux – energy spectrum, local and global anisotropy, flavor content - Transient sources (GRB, …) - Dark matter – indirect search - Exotic particles – monopoles, Q-balls, nuclearites, …

Str

ing

secti

on

, 12

OM

s

R ~ 60 m

L~

705

m

OM

12-16 OM 2-4 Sections 8 Strings To the shore

Section String Cluster

Structure elements of the detector

GVD desing Configuration10368 Optical modules, 216 Strings: 48 OM/Str., 4 Sec./Str. 27 Clusters: 8 Str/ClusterGeometry:Z = 15 m – distance between ОМ on stringR = 60 m – cluster radiusH = 300 m – distance between clustersInstrumented volume: ~1.5 km3

Depth: 600-1300 m Muons: (E>1 TeV):

Seff ~ 0.3–1.8 km2 ; δθmed < 0.5o ; δlg(E/E) ~0.4

10368 OMs

2304 OMs

10368 OMs

2304 OMs

Cascades: (E>10 TeV): Veff ~0.4–2.4 km3; δ(E/Esh) ~25%; δθmed~ 5o

In-situ tests of basic elements of GVD with

prototypes strings (2009...2010)

Investigation and tests of new optical modules, DAQ system, cabling system, triggering approaches

( LED Laser Muons)

NT200+

Prototype string 2009

Prototype string 2010

PMT: Photonis XP1807 6 OM Hamamatsu R8055

6 OM

PMT: Hamamat

su R7081HQ

E7 OM

Hamamatsu R8055

3 OM

GVD prototype strings 2009 - 2010

Zenith angular distributions of experimental and MC-simulated

events after cuts

- Performance of time measuring systems. - Reliability of calibration methods.- Efficiency of background suppression.

Selected sample of 2010 string data:

- Trigger condition: >3 hit OMs

- PMT noise: ~15kHz

Noise suppression procedure:The time difference between the pulses of any pair of OMs should be smaller than the light propagation time.

Muon track reconstruction:

Prototype string: muon reconstruction

Cluster 2011 technical designOptical modulesThe OMs house photomultipliers of different types:16 PMT R7081HQE (Hamamatsu, 10 inch) 5 PMT R8055 (Hamamatsu, 13 inch) 3 PMT XP1807 (Photonis, 12 inch

Strings• Size reduced section:8 optical modules, CM and SM.• CM (Central module): 2ADC board (8 chan.), Master .• SM (Service module): Control and connection to the cluster DAQ center. • Acoustic positioning system, 3 modules on each string. (accuracy ~2 cm, measurements each 30 sec)

Cluster DAQ centerCluster DAQ center provides the string triggering, power supply, and communication to shore.

Communication linesConnection between the strings and cluster DAQ center: 1.2 km copper cable. Connection to shore – optical cable 6 km.

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BAIKAL-GVD prototype cluster: 2011

In April 2011, a prototype cluster of GVD was installed in Lake Baikal.− 3 vertical strings with 8 optical modules each.− Vertical spacing between OMs is 10 m.− Horizontal distance between strings is 40 m.− Depths is 1205 – 1275 m.

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Sketch of prototype cluster, neutrino telescope NT200+, and communication lines locations.

NT200+ communication

lines

NT200+

Op

tica

l cab

le 2

011

248 “live” days

Present and nearest future

20123-strings, first fullscale GVD string

(24 ОМ)Data taking since

April 2012

2013 Detector with 3 full scale

GVD strings

2014-2015 Cluster (8 strings)

4106 м3106 м3

DAQ

DAQ DAQ

DAQ DAQ DAQ

Preproduction:

2014–2015. Full scale GVD cluster, 8 strings (192 Oms)

Production (preliminary)

2014–2018: 12-14 Clusters

2018–2020: Full scale detector ( 27 clusters )

Plans

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Summary1. Preparation towards a km3-scale Gigaton Volume Detector in

Lake Baikal is currently a central activity:

- In-situ tests of the prototype string shows good performance of basic string elements (2009-2010).

- A prototype GVD cluster with 3 strings was installed (2011) and shows stable work for whole year.

- New technology underwater optical cable was mounted (2011). - Full scale GVD string(24 OMs) with 2 “short” strings(6 OM)

taking data since April 2012.

2. Full scale GVD cluster (~200 OMs) is expected at 2014-2015.

GVD Technical Design Report was prepared (2011): http://baikalweb.jinr.ru/GVD/

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