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 Target muon (  ) cascade ( e     ) muoncascade 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 Winter expedition Summer expedition Day temperature Distance to shore ~4 km 1370 m maximum depth. No high luminosity bursts from biology. No K 40 background. Deployment simplicity: ice is a natural deployment platform Baikal, nm Absorption cross section, m -1 Scattering cross section, m -1 Baikal water properties: Abs. Length: 22 ± 2 m Scatt. Length: 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 km 3 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”) R Hamamatsu D=10 inch. SBA photocathode QE ≈ 400nm; Gain ~10 7, dark count ~8 kHz Quantum efficiency

 PMT: nominal gain: 1  10 7 ; Amplifier: k amp =14; Cable: ~0.7: 10 8 in total  Cable: 50 , 90 m, non coaxial underwater connectors;  Pulse after cable: ~20 ns FWHM, A 1E ~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: 10 7 Amplifier: 14FADC: ± 2V 90 m coax.cable OM Section electronic module A 1E distribution on all channels = 30 ch  A 1E ~ 10% PMT HV: 1250 – 1650 V Waveform stamp example: (5 mks) Single PE pulsesReflected 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). SeM MOXA IEX-402-SHDSL Section (basic DAQ cell) – 12 OM and Section electronics module (SeM). FADC MASTER SLOW CONTROL

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)

strings (36 OMs), First full-scale GVD string Launch: April 2012 yr full-scale strings (72 OMs) Section electronics updated Launch: April 2013 yr. Previous stages of “DUBNA” DAQ

strings (120 OMs) Launch: April strings (192 OMs) Launch: April 2015 Previous stages of “DUBNA”

Year Cluster 192 OM : 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

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Triggering and Data Transmission CLUSTER SECTION

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-dt 0 Measurement of signal delay of each channel Signal delay in cable (~90 m) is measured in lab. LED 15 m- distance between OMs dT 0 = 64.9 ns – expected time difference two LEDs dT reflected pulse Time difference of two channels dt Cable delay = dt/2 dt 0 =500 ns

Atmosphericmuondetection Trigger Coincidence of neighboring OM Selection – Q > 2 p.e. Time calibration: LED Data consistent with expectation dt distribution between neighboring channels

GVD Performance Cascades: (E>10 TeV): V eff ~0.4 – 2.4 km 3 Muons: (E>1 TeV): S eff ~ 0.3 – 1.8 km OMs 2304 OMs OMs 2304 OMs Direction resolution o Direction resolution: 3.5 o o IC-target mass for cascades