Gigaton Volume Detectorin Lake Baikal: status of the

project

 

Zh.-A. Dzhilkibaev (INR, Moscow)Zh.-A. Dzhilkibaev (INR, Moscow) for the Baikal Collaborationfor the Baikal Collaboration

QUARKS-2010, Kolomna, 6-12 June, 2010

1. Institute for Nuclear Research, Moscow, Russia.

2. Irkutsk State University, Russia.

3. Skobeltsyn Institute of Nuclear Physics MSU, Moscow, Russia.

4. DESY-Zeuthen, Zeuthen, Germany.

5. Joint Institute for Nuclear Research, Dubna, Russia.

6. Nizhny Novgorod State Technical University, Russia.

7. St.Petersburg State Marine University, Russia.

8. Kurchatov Institute, Moscow, Russia.

Telescope (E,)

input

water, ice Physics (E,)

Targetmuon ()

cascade(e)

output

muon cascade

E,

muons (long tracks) - ~ 0.3o – 1o, ~ 0.3logE cascades – > 30o (ice); ~ 3o – 6o (water) !

Cherenkov radiation

cascades

muon

Absorption

Scattering

Detection Principle – M. Markov 1960

energy, direction resolution

Ls < 3 m

Ls ~ 30-50 m

42o

A

NT200+/Baikal-GVD (~2017)

N N

KM3NeT(~2017)

Amanda/IceCube/IceCube(~2011)(~2011)

ANTARES

73 Strings in operation

Precursors of km3-scale neutrino telescopes: NT200 AMANDA ANTARES (Baikal) (South Pole) (Mediterranean Sea) Results:

Astrophysics HE-neutrinos

WIMPs in the Sun & the Earth

Neutrinos from GRB

Atm. neutrino flux

Magnetic monopoles etc.

Obtained results prove the detection principle and motivate the requirements of km3-scale facilities

IceCube(South Pole)

GVD(Lake Baikal)

KM3NeT(Mediterranean Sea)

MACRO

Limits on all flavor HE neutrino flux

IceCube (South Pole)

4800 Optical Modules80 Strings1500-2500 m depth ~1 km3 instrumented volume

Ice-Top – shower detection

Deep Core – low-energy neutrinos6 additional strings with dense OM spacing

2009-2010 yr.

73 + 6(Deep Core) – installed

IceCube will be completed in 2011/2012

2006-2007:

13 Strings

2005-2006:

8 Strings

2004-2005 :

1 String

2007-2008:18 Strings

1450 m

2450 m

2008-2009:

18+1 Strings

KM3NeT (Mediterranean Sea – TDR 2010)

8-inch PMT 31 3-inch PMTsOptical Module ?Research Infrastructure

Detection Unit (DU) ?Buoy

OM

OM

OM

OM

OM

Slender String 300 DU

SITE ?

Flexible tower 127 DU

Next Steps and Timeline

Next steps: Prototyping and design decisions- organised in Preparatory Phase framework- final decisions require site selection- expected to be achieved in ~18 months

Timeline:

CDR:TDR:

Mar

201

2

Design decision

Construction

2013

2017

2011

Data taking

2015

4км from the shore

1366 м depth

Shore Station

Location of the BAIKAL neutrino telescope

Location: - Northern hemisphere – GC (~18h/day) and Galactic Plane survey

- Flat 1350 m depth Lake bed (>3 km from the shore) – allows ~ 30 km3 Instr. Volume!

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

Since 1980 Site tests and early R&D started

1990 Technical Design Report NT200

1993 1993 NT36NT36 started: - the first underwater array - the first neutrino events.

1998 1998 NT200 commissioned:NT200 commissioned: start full physics program.

2005 NT200+ commissioned (NT200 & 3 outer strings).NT200+ commissioned (NT200 & 3 outer strings).

2006 Start R&D toward the Gigaton Volume Detector (GVD)

2008 2008 In-situ test of GVD electronics: 6 new technology optical In-situ test of GVD electronics: 6 new technology optical modulesmodules

2009-10 2009-10 Prototype strings for GVDPrototype strings for GVD

2010-112010-11 GVD cluster (3 strings), Technical Design ReportGVD cluster (3 strings), Technical Design Report

NT200: 8 strings (192 optical modules )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 (36 optical modules)Height x = 210m x 200m, Vinst = 5106m3

Eff. shower volume: 104 TeV ~ 10 Mton

Status of NT200+

LAKE BAIK

AL

~ 3.6 km to shore, 1070 m depth

NT200+ is operating now in Lake Baikal (~10 months/yr. persistent data taking)

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 > 10 TeV - Diffuse neutrino flux – energy spectrum, local and global anisotropy, flavor content - Transient sources (GRB, …)

Claster Str. section

315

- 460

m

GVD - Preliminary design

Layout:

~2300 Optical Modules, 96 Strings, 12 Clusters String comprises 24 OMs, which are combined in 2 independent SectionsCluster contains 8 strings

Instrumented volume: 0.4 – 0.6 km3

Detection Performance

Cascades: (E>100 TeV): Veff ~0.3–0.8 km3

δ(lgE) ~0.1, δθmed~ 3o-6o

Muons: (E>10 TeV): Seff ~ 0.2 – 0.5 km2

δθmed~ 0.3o-0.5o

Cable communication to shore

• 1370 m maximum depth • Distance to shore 4 … 5

km• 12 clusters × 192 OM• 12 cables ~ 6 km

GVD cluster

12 Shore cables

~6 km

1350…1370 m

Shore Center

12 GVD clusters

NT200+

Optimisation of GVD configuration (preliminary)

Parameters for optimization:Z – vertical distance between OMR – distance between string and cluster centreH – distance between cluster centres

Muon effective area

R=80 m

R=100 m

R=60 m

The compromise between cascade detection volume and muon effective area:

H=300 mR = 60 mZ = 15 m

Trigger: coincidences of any neighbouring OM on string (thresholds 0.5&3p.e.)

PMT: R7081HQE,10”, QE~0.35

GVD – R&D (2006-2010)

GVD - Key Elements and Systems:

- Optical Module- FADC-readout system- Section Trigger Logics - Calibration- Data Transport- Cluster Trigger System, DAQ - Data Transport to Shore

OM

12 OMs 2 Sections 8 Strings to Shore

Section String Cluster

Optical module

XP1807(12”), R8055(13”), R7081HQE(10”)

QE ~0.24 QE ~0.2

QE~0.35

HV unit: SHV12-2.0K,TracoPowerOM controllerAmplifier: Kamp = 10LED calibration system (2 LEDs)

Functional scheme of the optical module electronics

XP1807 R8055 R7081HQE

2008-2009 20102008-2010

0 1 2 3 4 5 60,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

XP1807 #1026

XP1807 #1006 R8055

#186 R8055 #314

R8055 #228

Rel

ativ

e P

M s

ensi

tiviti

es

PMT number

Relative sensitivities of large area PMs R8055/13” and

XP1807/12”

Measuring channels

BEGPMT1

Amplifier

FADC 1 90 m coax.cable

OM

PMT12

Amplifier

FADC 12

90 m coax. cable

…

BEG (FADC Unit) -3 FADC-board: 4-channel, 12 bit, 200 MHz;-OM power controller;-VME controller: trigger logic, data readout from FADC, connection via local Ethernet

Section – basic detection unitSection:

- 12 Optical Modules - BEG with 12 FADC channels and trigger unit- Service Module (SM): LEDs for OM calibration, OM power supply, acoustic positioning system.Basic trigger: coincidences of nearby OM (threch. ~0.5&3 p.e.) expected count rate < 100 HzCommunications: BEG cluster centre: DSL-modem, expected dataflow < 1Mbit/sBEG OMs: RS-485 Bus (slow control)

Cluster DAQ center

Cluster of strings

8 Strings

String consists of 2 sections

(2×12 OM)

Cluster DAQ Centre (4 modules)1.PC-module with optical Ethernet communication to shore (data transmission and synchronization) 2.Trigger module with 8 FADC channels (time mark of string trigger)3.Data communication module (8 DSL-modems for communication to strings, ~10 Mbit/s for 1 km )4.Power control system

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

R7081HQE

R8055

Prototype string deployment: April 2010

PC BEG1

SM

BEG2

Time resolution of measuring channels (in-situ tests with LED)

LED flasher produces pairs of delayed pulses. Light pulses are transmitted to each optical module (channel) via individual optical fibers. Delay values are calculated from the FADC data.

0 2 4 6 8 10 12

492

496

500

504

508 Expected dT = 497.5

dTLE

D ,

ns

# Channel

Measured delay dT between two LED pulses

0 2 4 6 8 10 120

50

100

150

200 A (LED1) p.e. A (LED2) p.e.

A, p.e.

#Channel

LED1 and LED 2 pulse amplitude

Example of a two-pulse LED flasher event (channel

#5)

LED1

LED2

(dT) 1.6 ns

Time accuracy (in-situ test with Laser)

LASER

11

0 m

OM#7OM#8

OM#9

OM#10

OM#11

OM#12

OM#1OM#2

OM#3

OM#4

OM#5

OM#6

97 m

r1

r2

10 20 30 40 50-8

-6

-4

-2

0

2

4

6

8

dTLA

SE

R

- dT

GE

OM

, n

s

dR, m

Differences between dT measured with Laser and

expected dT in dependence on distances between

channels dr

T < 3 ns

Test with LASER

T = <dTLASER – dTEXPECTED>

dTEXPECTED = (r2-r1)cwater

dTLASER - time difference

between two channels measured for Laser pulses (averaged on all channel

combinations with fixed (r2-

r1))

Distribution of time difference T between muon pulses for two up-ward looking PMTs:

experiment and expectation from atm. muons.

T between muon pulses

detected with different

channels are studied and

compared with simulation of

the string response to the

atmospheric muon flux.

Trigger: 3-fold OM

coincidences

Muon detection

MC

Schedule:

>2006 Activity towards the Gigaton Volume Detector

2008-10 Prototype Strings ( test of GVD key elements and systems)

2010-11 Technical Design Report

2010-12 Preparatory Phase, Prototype of Cluster (in-situ test) 2011-16 Fabrication (OMs, cables, connectors,

electronics)

2012-17 Construction (0.2 0.4 0.6 0.8 1.0) GVD