Baikal-GVD: status and plans

 

Denis Kuleshov Denis Kuleshov INR, Moscow, Oct 28, 2015

1. Project overview and detector design

2. GVD DAQ architecture 3. Current status and plans

4. Summary

OUTLINE

Primary objectives

Galactic and extragalactic neutrino “point sources” in energy range > 1 TeV Diffuse neutrino flux – energy spectrum, local and global anisotropy, flavor content Dark matter – indirect search

Telescope (E,)

input

water, ice

Targetmuon ()

cascade(e)

muon cascade

Detection principle

e

Large Volume Neutrino Telescopes

The Baikal Collaboration

• Institute for Nuclear Research, Moscow, Russia.• Joint Institute for Nuclear Research, Dubna, Russia.• Irkutsk State University, Irkutsk, Russia.• Skobeltsyn Institute of Nuclear Physics MSU, Moscow, Russia.• Nizhny Novgorod State Technical University, Russia.• St.Petersburg State Marine University, Russia.• Institute of Experimental and Applied Physics, Czech Technical • University, Prague, Czech Republic.• Comenius University, Bratislava, Slovakia.• EvoLogics Gmb., Berlin, Germany.

The Baikal-GVD Project

Winterexpedition

Summer expedition

Day temperature

• Distance to shore ~4 km• 1370 m maximum depth.• No high luminosity bursts from biology.• No K40 background.• Deployment simplicity: ice is a natural

deployment platform

Baikal

Baikal

, nm , nm

Ab s

orpt

ion

cros

s se

c tio

n , m

-1

Scat

terin

g cr

oss

sect

ion,

m-1

Baikal water properties:

Abs. Length: 22 ± 2 m Scatt. Length: 30-50 m

Irkutsk

GVD

Detector design

Basic principles of GVD design:-Simplicity of all elements;-Deployment convenience from the ice cover;-Detector extensibility and configuration flexibility.

Basic GVD elements-Optical module (OM);-Section: 12 OM (spaced by 15m) & Section electronic module (12 FADCs)-String: 3 (±1) Sections & String electronic module-Cluster: 8 strings & DAQ center.

Volume: 0.4 km3

Cluster with 8 two-section strings

GVD Optical module

Φ220 mm

Angular sensitivity

OM electronics

Mu-metal cage

PMT

Optical gel

Glass pressure-resistant sphere VETROVEX (17”)

R7081-100 Hamamatsu D=10 inch. SBA photocathode QE ≈ 35% @ 400nm; Gain ~107, dark count ~8 kHz

Quantum efficiency

PMT: nominal gain: 1107; Amplifier: kamp=14; Cable: ~0.7: 108 in total Cable: 50, 90 m, non coaxial underwater connectors; Pulse after cable: ~20 ns FWHM, A1E ~40 mV; FADC: 12 bit 200 MHz; range ± 2V, waveform stamp up to 5 mks; Count rate (0.3 PE) 20 … 40 kHz, max. electronics noise ~10mV.

Measuring channel

PMT: 107 Amplifier: 14 FADC: ± 2V 90 m coax.cable

OM Section electronic module

A1E distribution on all channels<A1E> = 30 ch A1E ~ 10%

PMT HV: 1250 – 1650 VWaveform stamp example: (5 mks)

Single PE pulses Reflected pulse

GVD Section

12-channel ADC unit: PMTs analog pulse conversion, time synchronization, data processing, local trigger. FPGA (Xilinx Spartan 6)Data transmission: Two outputs of ADC board: optical output (for future detector extension) and 100 BASE-TX (present stage).shDSL modem: Extending the Ethernet line up to 1 km.Slow control board: OM power on/off and control of OM operation (RS485).

SeMM

OX

A I

EX

-402

-SH

DS

L

Section (basic DAQ cell) – 12 OM and Section electronics module (SeM).

FADC

MASTER

SLOW CONTROL

Inte

rfac

e ADC boardADC board

Master board

300 VDC commutator

300 VDC In

To shore

8 ADC channels

Data, Requests

8

8

8

300 VDC Out

Data

Reguests

String1 String 8- - -

DSL-modem

DSL-modem

DSL-modem

DSL-modem

DSL-modem

DSL-modem

DSL-modem

DSL-modem

Global trigger

8E

th

com

mut

ato

r

SFP module

SFP module

Optical ch 1

Optical ch 2

Cluster DAQ center

Trigger Module:2 ADC board (8 channels) and Master board ADC inputs: 8 string trigger requests; Master output: global trigger for 8 strings. Power Module:300VDC 12-ch manageable commutator.Optical module: conversion 1000 BASE FX to 100 BASE TX.

Cluster – 8 strings and DAQ center DAQ center: trigger logic, string power supply, communication to shore.Cluster center electronics located in 3 glass sphere and metallic box for optical cable attachment “optical box”.

Data module:-8 DSL-modems for transmission the string data.-8-channel COM-server for DSL speed control.

Particle registration

Deployment procedure

Current status of the “DUBNA”

• Operation: 206 Days• Total: 425 Runs• Data : 4 10∙ 8 events• Monitoring: 1.3 10∙ 6 events

String 5, Section 2 (Up)

20123 strings (36 OMs),

First full-scale GVD string Launch: April 2012 yr.

2013 3 full-scale strings (72 OMs) Section electronics updated

Launch: April 2013 yr.

Previous stages of “DUBNA”

DAQ

DAQ DAQ

DAQ DAQDAQ

2014 5 strings (120 OMs)

Launch: April 2014

2015 8 strings (192 OMs)

Launch: April 2015

Previous stages of “DUBNA”

Year 2015 2016 2017 2018 2019 2020

Cluster192 OM

1192

1192

3576

5960

71344

101920

2015-2016: organization of mass production

GVD Timeline

Assuming IC flux, 1 cluster ~ 1 event with E > 100 TeV/year

Conclusion

• Baikal Collaboration has more than 30 yers of an extensive positive experience of development, construction and operation of underwater facilities in Lake Baikal.

• The key elements and systems of the GVD have been developed, produced and tested in Lake Baikal. Scientific-Technical Report (STR) has been prepared.

• Prototyping & Early Construction Phase of Project was concluded with construction and commission of the first GVD cluster “DUBNA” in April 2015.

http://baikalweb.jinr.ru/GVD

19

Triggering and Data Transmission

CLUSTERSECTION

Amplitude calibration

LED1

Low Int.

LED2

high Int.

Calibration methods:

1 – two LEDs with high and low (~10% OM detection probability) intensities

2 – analysis of noise pulses

1 ph.el.

Code/charge

Code/ampl.

Time calibration – two methods

PMT signal delay = dt-dt0

Measurement of signal delay of each channel

Signal delay in cable (~90 m)is measured in lab.

LED15 m- distance between OMsdT0 = 64.9 ns – expected time difference

two LEDs

dT

reflected pulse

Time differenceof two channels

dt

Cable delay = dt/2

dt0=500 ns

Atmospheric

muon

detection

TriggerCoincidence of neighboring OM

Selection – Q > 2 p.e.

Time calibration: LED

Data consistent with expectation

dt distribution between neighboring channels

GVD PerformanceCascades: (E>10 TeV):

Veff ~0.4–2.4 km3

Muons: (E>1 TeV): Seff ~ 0.3–1.8 km2

10368 OMs

2304 OMs

10368 OMs

2304 OMs

Direction resolution - 0.25oDirection resolution: 3.5o - 5.5o

IC-target mass for cascades