data acquisition system for the baikal-gvd neutrino telescope denis kuleshov valday, february 3,...
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Data acquisition system for the Baikal-GVD neutrino telescope
Denis KuleshovDenis Kuleshov Valday, February 3, 2015
1. GVD DAQ architecture
2. Basic elements of the telescope: - Optical module and measuring channel - OM Section and String - GVD Cluster - Underwater Cluster network
3. Reliability
Summary
OUTLINE
GVD DAQ architecture
Cluster DAQ center
Section electronic module
Optical module
String electronic module
SE
CT
ION
SE
CT
ION
ST
RIN
G
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 15 m) Section electronic module (12-ch FADC)
-String: 2 or 3 Sections & String electronic module
-Cluster: 8 strings & DAQ center.
R ~ 60 mH
~ 35
0 m
Cluster with 8 two-section strings
Optical module and measuring channel
HV converter: SHV 12-2.0 K 1000 P 0 …+ 2000 VDC, stability 0.05% ripple and noise 8 mVpk-pk
Passive divider: 18 M2-channel amplifier: Output channel and PMT noise monitoring channel.
2 LEDs L7113: 470 nm, 5-7 ns- regulation of intensities in the range 1…~108 photons (100m Baikal water)- LED pulse delay regulation: 0 … 1000 ns
Slow control board: SiLabs C8051F121Control of electronics operation and monitoring of PMT parameters via RS485 interface.
OM electronics
Mu-metal cage
PMT
Optical gel
Glass sphere VETROVEX (17”)
Optical module design: as simple as possible.
OMSEM
PMT: 107 Ampl. ADC Board
90 m coax. cable
GVD Section
12-channel ADC unit: PMTs analog pulse conversion, time synchronization, data processing, local trigger.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 (RS-485).
Flash ADC (AD9430) 12bit, 200 MSPS
FPGA (Xilinx Spartan 6) Enable to on-line data filtration. Cut the pulses from data frame and paste to output data stream. Rejection factor : 50-100
Section electronic module
Optical output
Section (basic DAQ cell) – 12 OM and Section electronics module (SeM).
Functional scheme of one FADC channel
ADC 200 MSPS
Duble-buffered memory,
30 mks WF data
Datatransmitter
Data control
Peak detectorAmplitude analyser
Smoothing2-level
comparator
Inte
rface
Trigger/Stop
Waveform, 5 mks
Histogram
Request builder
Channel request
L
H
Smoothing level 1...8
Accumulation time
Waveform interval
Thresholds
PMTpulse
FPGAFADC (AD9430) 12bit, 200 MSPS FPGA (Xilinx Spartan 6) - Trigger logic: 2-level adjustable digital comparator forms low threshold L and high threshold H channel requests (section trigger is L&H coincidence of neighboring channels). - Data channel (triggered) consists of double-buffered memory and data transmitter.- Monitor channel (non-triggered) includes peak detector and amplitude analyzer.
LED pulse
Noise
Waveform stamp example (5 mks)
Single PE pulses
Monitor histogram examples
Monitor channelData channel
ADC channel
Trigger Commutator: splits for the section acknowledges & combines requests.
Data transmission: DSL line.
Power Commutator: Controls power to the SEM, OMs and peripherals.
String communication module combines 2 or 3 sections.
Functions:
GVD String
Functional scheme of Power Commutator
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GVD ClusterCluster - a full functional detection system, working both independently and as a part
of the full detector.Cluster – 8 strings and DAQ center. DAQ center: trigger logic, string power supply, communication to shore.Cluster center electronics is located in 3 glass spheres and metallic box for optical cable attachment “optical box”.
Optical boxCluster DAQ center
Cluster DAQ center
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GVD Cluster
Power Module:300VDC 12-ch manageable commutator.
Optical Box: conversion 1000 BASE-FX to 100 BASE-TX.
Data module:8 DSL-modems for transmission the string data.8-channel COM-server for DSL speed control.
Trigger Module:12-channel ADC unit: 8 string trigger requests, global trigger for 8 strings.
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Cluster underwater network
Segments of underwater network:1. Section electronics module – String module2. String module – Cluster DAQ center3. Cluster DAQ center – Optical box4. Optical box – Shore DAQ center
100…200 Hz data event rate are expectedfor the basic trigger L×H.
Section Line speed, Кbit/s SNR, dB
String 1 7040 11
String 2 7552 12
String 3 10048 11
String 4 10048 10
String 5 10048 12
Segment Length Data rate
Line speed Technique
1 100…300 m
1 Mbit ~10 Mbit shDSL
2 ~1000 m 3 Mbit ~10 Mbit shDSL
3 3 m 25 Mbit 100 Mbit 100 BaseTX
4 ~6000 m 25 Mbit 1000 Mbit 1000 BaseFX
(1) Slow data transmission (triggered mode):OM coincidences produce a trigger that rejects the
PMT noise.
(2) Fast data transmission*: optical line from ADC module to Shore Center (all data to shore).
Possibility to use two modes of operation:
Data line speed in 2014
1. Optical modules:The OM electronics failure rate: 3 OM / 140 / Year - 1 OM: HV control system. Failure of the OM controller. - 2 OM: not connection via RS485 bus (out of operation at April 2014). Probable reason is transient error of the slow control board (it was modernized in late 2014). 2. Cable communications: 2 cables are out of operation. Reason - old technology of the sealing (cables of 2011). New sealing technology is applied after 2012.3. Network devices a) Industrial devices (Switches, Eternet-RS485 converters, IEX-402 DSL) – no failure b) Non-industrial DSL-modems: - Unreliable connection to 1 string at 2013 and 1 Section at 2014. We plan to use industrial IEX-402 shDSL, that were presented by MOXA firm at 2013.4. ADC boards - no failure.5. Glass sphere and Connectors - no failure.6. Power supply units (300 VDC commutators, DC/DC converters) - no failure
Reliability
(without long-term laboratory tests and stress tests)
Results from 2011 up to end of 2014
Summary
1. DAQ system was tested with 5-strings engineering array and will be applied
for GVD-Baikal full functional Cluster in this year.
2. Baikal-GVD technical design is basically finalized.
3. Next step of the DAQ development is investigation the possibility to use optical
connections with sections. - Optical hybrid cable is designed (connection between Cluster Center and
Shore)- Optical output of ADC board (SEM) is foreseen.- Optical connectors ???
Backup slides
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FADC (AD9430) 12bit, 200 MSPS FPGA (Xilinx Spartan 6) - Trigger logic: 2-level adjustable digital comparator forms low threshold L and high threshold H channel requests- Data channel (triggered) consists of double-buffered memory and data transmitter.- Monitor channel (non-triggered) includes peak detector and amplitude analyzer.
ADC board12-ch 200 MSPS
ADC
- Trigger logic(L&H coincidence of neighboring channels- Data readout from ADC buffer - Control of OM mode of operation - Connection via local Ethernet to the cluster DAQ center
Triggering and Data Transmission
SECTION CLUSTER
Prototype arrays: 2012: 36 OM, 2013: 72 OM, 2014: 120 OM
A summarized time of the OMs operation is ~170 years
3 OM failures during this period:
- 1 OM: HV control system out of operation (2013).
- 2 OM: not reliable connection via RS485 bus (2014).
The OM electronics failure rate ~2% / year
Repairing possibility: 8% / year for 100 strings installation (GVD Phase 1).
OM reliability
(without stress tests of electronics during prototyping phase )
Results from 2012 to 2014