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
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Ab s
orpt
ion
cros
s se
c tio
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Scat
terin
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oss
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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