sinp msu, july 7, 2012 i.belolaptikov behalf baikal collaboration
TRANSCRIPT
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.
11
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.
12
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
14
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/
15
16