1. Status of the Baikal-GVD experiment - 2017
35th ICRC July 14
Vladimir Aynutdinov, INR RAS

2. Gigaton Volume Detector in Lake Baikal (Baikal-GVD)
9 institutes
~60 physicists and engineers
Gigaton Volume Detector in Lake Baikal (Baikal-GVD)
IIrkutsk Univ
St-Petersburg
Marin Tech. U
INR
N-Novgorod
Tech. U
JINR
EvoLogics, Germany
MSU
Czech Technical U
Comenius U, Slovakia.
baikalweb.jinr.ru

3. Baikal-GVD Site: 1370 m maximum depth Eff. volume 1.5 км3
Baikal water
Abs.Length: 22 ± 2 m Scatt.Length: m
Eff. volume 1.5 км3
104 optical modules
Site:
1370 m maximum depth
Distance to shore ~4 km
No high luminosity bursts from biology.
No K40 background.
Central Physics Goals
Galactic and extragalactic neutrino “point sources”
Diffuse neutrino flux: spectrum, anisotropy, …
Transient sources: GRB, …
Dark Matter (indirect search)
Exotic particles: monopoles, …

4. Baikal-GVD phase 1 (GVD-1)
525 m
120 m
700 m
Optical module
one fourth of
String: 36 OMs
Cluster: 8 strings
GVD-1: 8 clusters
GVD-1
GVD-4
OMs
2304
10368
Clusters (8 Strings) 8 27
Depths, m
750 – 1275
600 – 1300
Eff. Volume (ESH > 100 ТeV)
0.4 km3
1.5 km3
Directional resolution
Cascades: 3 – 5
Muons: 0.25

5. The Optical Module OM electronics Mu-metal cage PMT Optical gel
Hamamatsu R =10 inch
QE ≈ 400nm
Gain ~107,
Dark current ~8 kHz
OM electronics
Mu-metal cage
PMT
Optical gel
Pressure-resistant
glass sphere
VITROVEX (17”)

6. DAQ system Channel OM: analog output, gain ~108
GVD Section: 12 channels
Channel
OM: analog output, gain ~108
ADC: 12-bit 200 MSPS (waveform)
Section: 12 optical modules
Trigger: coin. any pairs of nearby OMs
Master records: waveforms of 12 channels
Data transmitting: 2-wire Eth. Extenders
(time intervals without pulses are clipped)
String: 3 strings
Section power control
Cluster: 8 strings
Data transmitting: optical line
Event rate: 50 – 250 Hz

7. Assembling the detector
Detector deployment from the ice.
Deployment period:~20 February … ~10 April
A conditions for the installation of two clusters in the season are prepared.

8. Stages of deployment of the Baikal-GVD
Configuration
2015
2016
2017
The number of OMs
192 (8str24)
288 (8str36)
576
Geometric sizes
80m×345m
120m×525m
2×120m×525m
Eff. Vol. (E > 100TeV)
0.03 km3
0.05 km3
0.1 km3
Cluster-2016 operation
Live time
Full time
Eff %
Master Records
235d 0h
302d 15h
77.7
1,796,646,941

9. Detector operation -2017 13 April – 15 Jun 2017
Cluster 1
Statistic of two clusters operation since April 13 up to June 15 of 2017
Full time
days
Eff., %
Master records
Cluster-1
64d 7h
84.4
1.87×108
Cluster-2
64d 0h
87.6
1.45×108
Cluster 2

10. Deep-water pulsed laser
Wavelength: 532 nm
Pulse energy: 0.37 mJ (~1015 photons)
Flash duration ~1 ns
Purposes:
- inter-cluster calibration
- cascade emulation
LASER
Depth: ~1200 m
Distance to the nearest strings:
64 m: Cluster 1, m: Cluster 2
Poster: Kirill Golubkov

11. The first tests of the laser operation
Amplitude
Q, pe S6 S7 S8 S5 S4 S3 S1
64 m
LASER
Time
Check up of main parameters of the detector:
Uncertainties of the timing calibration
Precision of the OMs positioning.

12. Cascade showers detection
Poster: Bair Shaybonov
The first GVD cluster:
data sample:
24 Oct - 17 Dec 2015
41.6 days of live time
4.4×108 events.
1192 events were reconstructed as a cascade-like events with energy E >102 TeV
Distribution of events on multiplicity of the triggered channels (Nhit) in comparison with background from atm
One event with Nhit =17: E ~102 TeV,  = 56.6
Probability Nhit >16 : 5% (E-2.46)
Further investigations of atm background for large Nhit are in progress now.

13. Summary
Prototyping & Early Construction Phase of Baikal-GVD project is concluded with construction and commission of the first GVD Cluster “DUBNA” in 2015
Array “DUBNA” was upgraded to baseline configuration of GVD cluster with 288 OMs in 2016.
The second full-scale GVD cluster was installed and commissioned in April 2017.
Completion of the GVD-1 is expected in 2020.
Year
2016
2017
2018
2019
2020
Cluster OM
Eff. vol, km3 1
288
0.05 2
576
0.1 4
1152
0.2 6
1728
0.3 8
2304
0.4

14. Thank you for your attention