Commit c7815469 authored by Maciej Lipinski's avatar Maciej Lipinski

WIP: article

parent 77b72b16
all : wrApplicationsOverview.pdf
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@misc{biblio:whiteRabbit,
title = "{White Rabbit Project}",
howpublished = {\url{http://www.ohwr.org/projects/white-rabbit}}
}
@misc{biblio:whiteRabbitCERN,
title = "{White Rabbit}",
howpublished = {\url{http://www.cern.ch/white-rabbit}}
}
@ARTICLE{biblio:802.1Q,
journal="{IEEE Std 802.1Q-2014}",
title={{IEEE} {Standard} for {Local} and {Metropolitan} {Area} {Networks--Bridges} and {Bridged} {Networks}},
year={2014},
month={Dec},
keywords={IEEE standards;access protocols;local area networks;metropolitan area networks;IEEE standard;MAC service;VLAN bridges;bridged networks;local area networks;media access control service;metropolitan area networks;Bridged circuits;IEEE standards;Local area networks;Media Access Protocol;Metropolitan area networks;Protofcols;Virtual environments;Bridged Network;IEEE 802.1Q(TM);LAN;MAC Bridge;MSTP;Multiple Spanning Tree Protocol;PBN;Provider Bridged Network;RSTP;Rapid Spanning Tree Protocol;SPB Protocol;Shortest Path Bridging Protocol;VLAN Bridge;Virtual Bridged Network;local area network;metropolitan area networks;virtual LAN},
doi={10.1109/IEEESTD.2014.6991462},}
@online{biblio:allan90,
author = {D.B. Sullivan and D.W. Allan and D.A. Howe and F.L. Walls},
title = {{Characterization of Clocks and Oscillators}},
url = {http://tf.nist.gov/general/pdf/868.pdf},
note = "{NIST Technical Note 1337}",
urldate = {1990},
}
@article{biblio:IEEE802.3,
journal="{IEEE 802.3-2012}",
title = {{IEEE Standard for Ethernet}},
doi = {10.1109/IEEESTD.2012.6419735},
abstract = {Ethernet local area network operation is specified for selected speeds of operation from 1 Mb/s to 100 Gb/s using a common media access control ({MAC}) specification and management information base ({MIB}). The Carrier Sense Multiple Access with Collision Detection ({CSMA}/{CD}) {MAC} protocol specifies shared medium (half duplex) operation, as well as full duplex operation. Speed specific Media Independent Interfaces ({MIIs}) allow use of selected Physical Layer devices ({PHY}) for operation over coaxial, twisted-pair or fiber optic cables. System considerations for multisegment shared access networks describe the use of Repeaters that are defined for operational speeds up to 1000 Mb/s. Local Area Network ({LAN}) operation is supported at all speeds. Other specified capabilities include various {PHY} types for access networks, {PHYs} suitable for metropolitan area network applications, and the provision of power over selected twisted-pair {PHY} types.},
date = {2012-12},
keywords = {1000BASE, 100BASE, 100GBASE, 100 Gigabit Ethernet, 10BASE, 10GBASE, 10 Gigabit Ethernet, 40GBASE, 40 Gigabit Ethernet, attachment unit interface, {AUI}, Auto Negotiation, Backplane Ethernet, bit rate 1 Mbit/s to 100 Gbit/s, carrier sense multiple access, carrier sense multiple access with collision detection, coaxial cable, coaxial cables, computer network management, {CSMA}-{CD}, data processing, {DTE} Power via the {MDI}, {EPON}, Ethernet, Ethernet in the First Mile, Ethernet networks, Ethernet passive optical network, Fast Ethernet, formal specification, full duplex operation, Gigabit Ethernet, {GMII}, {IEEE} standards, {IEEE} Std 802.3-2008 Revision, {IEEE} Std 802.3-2012, information exchange, local area network, {MAC} protocol specification, management, management information base, {MDI}, media access control, media independent interface, medium dependent interface, metropolitan area network, Metropolitan area networks, {MIB}, {MII}, multisegment shared access network, network interfaces,
optical fibre {LAN}, optical repeaters, Passive optical networks, {PHY}, physical coding sublayer, Physical layer, physical layer device, physical medium attachment, {PMA}, Power over Ethernet, repeater, twisted pair cable, twisted pair cables, type field, {VLAN} {TAG}, {XGMII}}
}
@article{biblio:IEEE1588,
journal = "{IEEE 1588-2008}",
title = "{IEEE} {Standard} for {Precision}
{Clock} {Synchronization} {Protocol} for {Networked} {Measurement} and {Control} {Systems}",
organization = "IEEE",
address = "New York",
}
@Misc{biblio:WRPTP,
author = "E.G. Cota and M. Lipi\'{n}ski and T. W\l{}ostowski and E.V.D. Bij and J. Serrano",
title = "{White Rabbit Specification: Draft for Comments}",
note = "CERN Document, v2.0",
month = "July",
year = "2011",
howpublished = {\url{http://www.ohwr.org/documents/21}}
}
@inproceedings{biblio:ISPCS2011,
author = "M. Lipi\'{n}ski and T. W\l{}ostowski and J. Serrano and P. Alvarez",
title = "{White Rabbit: a PTP application for robust sub-nanosecond synchronization}",
booktitle = "Proceedings of International IEEE Symposium on Precision Clock Synchronization for Measurement, Control and Communication (ISPCS)",
address = "Munich, Germany",
year = "2011",
}
@Inproceedings{biblio:WRproject,
author = "J. Serrano and P. Alvarez and M. Cattin and E. G. Cota and J. H. Lewis, P.
Moreira and T. W\l{}ostowski and others",
title = "{The White Rabbit Project}",
booktitle = "Proceedings of International Conference on Accelerator and Large Experimental Physics Control Systems (ICALEPCS)",
address = "Kobe, Japan",
year = "2009",
}
@mastersthesis{biblio:TomekMSc,
author = "T. W\l{}ostowski",
title = "Precise time and frequency transfer in a {White} {Rabbit} network",
month = "May",
year = "2011",
address ="Warsaw, Poland",
school = "Warsaw University of Technology",
howpublished = {\url{http://www.ohwr.org/documents/80}}
}
@thesis{biblio:MaciekPhD,
author = "Lipinski, Maciej",
title = "{Methods to Increase Reliability and Ensure
Determinism in a White Rabbit Network}",
year = "2016",
reportNumber = "CERN-THESIS-2016-283",
url = "http://cds.cern.ch/record/2261452",
note = "Presented 04 Apr 2017",
}
@thesis{biblio:CesarPhD,
author = "Prados, Cesar",
title = "{Rock Solid WR Network for GSI/FAIR Control System}",
year = "Unpublished doctoral thesis",
school = "Technische Universität Darmstadt",
address = "Darmstadt, Germany"
}
@ARTICLE{biblio:JosePhD,
author={F. Ramos and J. L. Gutiérrez-Rivas and J. López-Jiménez and B. Caracuel and J. Díaz},
journal={IEEE Transactions on Industrial Informatics},
title={Accurate Timing Networks for Dependable Smart Grid Applications},
year={2018},
volume={14},
number={5},
pages={2076-2084},
keywords={clocks;electrical safety;power system interconnection;power system security;satellite communication;smart power grids;substation automation;complex system;deterministic timing reference;interconnected system;satellite clock;smart grid applications;substation automation system;system reliability;timing networks;timing signal;Protocols;Safety;Security;Smart grids;Substations;Synchronization;Dependability;White Rabbit (WR);high-availability seamless redundancy protocol (HSR);safety-critical;scalability;smart grid;synchronization},
doi={10.1109/TII.2017.2787145},
ISSN={1551-3203},
month={May},}
@online{biblio:CERN,
title = {{European Organization for Nuclear Research (CERN)}},
url = {www.cern.ch/},
howpublished = {\url{https://www.cern.ch/}},
abstract = {{CERN}, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works.},
urldate = {2014-06-17},
keywords = {{CERN}, high-energy physics, Large Hadron Collider, {LHC}, particles, physics, science},
}
@inproceedings{biblio:GMT,
author = "J.Serrano and P.Alvarez and D.Dominguez, J.Lewis",
title = "{Nanosecond} {Level} {UTC} {Timing} {Generation} and {Stamping} in {CERN}'s {LHC}",
booktitle = "Proceedings of International Conference on Accelerator and Large Experimental Physics Control Systems (ICALEPCS)",
address = "Gyeongju, Korea",
year = "2003",
}
@misc{biblio:GMTJavierPres,
title = {{CERN} {General} {Machine} {Timing} {System}: status and evolution},
author = {{J. Serrano}},
date = {2008-02-15},
note={CERN Presentation},
year=2008,
file = {CERN-GMT.pdf:/home/mlipinsk/.mozilla/firefox/64taeemp.default-1397950810482/zotero/storage/F3RGN3RC/CERN-GMT.pdf:application/pdf},
howpublished = {\url{https://indico.cern.ch/event/28233/contribution/1/material/slides/1.pdf}},
}
@electronic{biblio:P1588WG,
title = "{IEEE P1588 Working Group}",
howpublished = {\url{ieee-sa.centraldesktop.com/1588public}}
}
@Inproceedings{P1588-HA-enhancements,
author={O. Ronen and M. Lipinski},
booktitle={2015 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS)},
title={Enhanced synchronization accuracy in IEEE1588},
}
@electronic{biblio:fmc-dio-5cha,
title = "{FMC 5-channel Digital I/O module}",
howpublished = {\url{https://www.ohwr.org/projects/fmc-dio-5chttla/wiki/wiki}}
}
@electronic{biblio:fmc-dio-del,
title = "{MC DEL 1ns 4cha delay module }",
howpublished = {\url{https://www.ohwr.org/projects/fmc-delay-1ns-8cha/wiki/wiki}}
}
@electronic{biblio:fmc-tdc-5cha,
title = "{FMC TDC 1ns 5cha}",
howpublished = {\url{https://www.ohwr.org/projects/fmc-tdc/wiki/wiki}}
}
@misc{biblio:WR@LIST,
title = {{LHC} {Instabilities} {Trigger} {Distribution}},
url = {https://indico.cern.ch/event/295937/contribution/1/material/slides/0.pdf},
author = {T. Wlostowski},
note="{CERN Presentation}",
howpublished = {\url{https://indico.cern.ch/event/295937/contribution/1/material/slides/0.pdf}},
date ="2014"
}
@inproceedings{biblio:WR-LIST,
author = "T. Wlostowski and J. Serrano and G. Daniluk and M. Lipinski and F. Vaga",
title = "{Trigger and RF distribution using White Rabbit}",
booktitle = "{Proceedings of International Conference on Accelerator and Large Experimental Physics Control Systems (ICALEPCS)}",
year = "2015",
URL = {http://icalepcs.synchrotron.org.au/papers/wec3o01.pdf},
howpublished = "{\url{http://icalepcs.synchrotron.org.au/papers/wec3o01.pdf}}"
}
@electronic{biblio:wr-streamers,
title = "{White Rabbit Streamers IP Core}",
howpublished = {\url{https://www.ohwr.org/projects/wr-cores/wiki/wr-streamers}}
}
@INPROCEEDINGS{biblio:wr-cngs,
author={M. Lipinski and T. Wlostowski and J. Serrano and P. Alvarez and J. David Gonzalez Cobas and A. Rubini and P. Moreira},
booktitle={2012 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control and Communication Proceedings},
title={Performance results of the first White Rabbit installation for CNGS time transfer},
year={2012},
volume={},
number={},
pages={1-6},
keywords={Global Positioning System;computerised instrumentation;local area networks;sensors;time measurement;ADEV;Allan deviation;CERN Neutrino to Gran Sasso project;CNGS time transfer;GPS receiver;Global Positioning System receiver;Gran Sasso National Laboratory;IEEE 1588-2008 standard;MTIE;UTC;WR installation;climatic chamber testing;coordinated universal time;data collection;frequency transfer system;maximum time interval error;synchronous Ethernet-based network;time receiver;time reference;time transfer evaluate;time transfer system;underground extraction-detection point;white rabbit installation;Accuracy;Delay;Global Positioning System;Liquefied natural gas;Monitoring;Synchronization;Temperature measurement},
doi={10.1109/ISPCS.2012.6336610},
ISSN={1949-0305},
month={Sept},}
@Misc{biblio:PolaRx4e,
title = "{PolaRx4/PolaRx4TR: Multi-frequency GNSS Reference Station}",
howpublished = {\url{www.chronos.co.uk/files/pdfs/sep/PolaRx4.pdf}}
}
@Misc{biblio:CS4000,
title = "{Symmetricon frequency standards, Symmetricom, Time and Frequency Systems}",
howpublished = {\url{http://www.symmetricom.com/products/frequency-references/cesium-frequency-standard/Cs4000/}},
}
@online{biblio:WR-Btrain-MM,
title = "{Real-Time Distribution of Magnetic Field Measurements Over White-Rabbit}",
year = "2016",
author = "M. Roda",
urldate = "2016-03-16",
}
@Misc{biblio:WR-Btrain,
title = "{{BTrain} over White Rabbit}",
howpublished = "{\url{https://gitlab.cern.ch/BTrain-TEAM/Btrain-over-WhiteRabbit/wikis/home}}"
}
@Misc{biblio:WR-Btrain-status,
title = "{Real-Time distribution of magnetic field values using White Rabbit the FIRESTORM project}",
howpublished = "{\url{https://indico.cern.ch/event/640522/contributions/2597939/attachments/1472607/2279328/BE-CO-TM-WR-BTrain.pdf}}"
}
@techreport{biblio:FAIRtimingSystem,
author = "T. Fleck and C. Prados and S. Rauch and M. Kreider",
title = "{FAIR Timing System}",
institution = "GSI",
address = "Darmstadt, Germany",
year = "2009",
note = "v1.2",
}
@Misc{biblio:GSI,
title = "{GSI Helmholtz Centre for Heavy Ion Research}",
howpublished = "{\url{https://www.gsi.de/en/about\_us.htm}}"
}
@inproceedings{biblio:WR-GSI,
author = "C.Prados and A.Hahn and J.Bai and A.Suresh",
title = "{A Reliable White Rabbit Network for the FAIR General Machine Timing}",
booktitle = "{Proceedings of International Conference on Accelerator and Large Experimental Physics Control Systems (ICALEPCS)}",
year = "2017",
howpublished = "{\url{http://accelconf.web.cern.ch/AccelConf/icalepcs2017/papers/tupha091.pdf}}"
}
@thesis{biblio:MathiasPhD,
author = "Kreider, Mathias",
title = "{On Time, in Style: Nanosecond Accuracy in Network Control Systems}",
year = "2017",
school = "University of Wales",
howpublished = "{\url{https://www-acc.gsi.de/wiki/pub/Timing/TimingSystemDocuments/kreiderPhdwiki.pdf}}"
}
@Misc{biblio:GSI-schedule,
title = "{GSI - General Plan of Accelerator Operation 2018}",
}
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\documentclass[conference]{IEEEtran}
\usepackage{listings}
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\title{Overview of White Rabbit Applications and Status}
\author{
\IEEEauthorblockN{Maciej Lipi\'{n}ski, Erik Van Der Bij, Javier Serrano, Tomasz Wlostowski, Grzegorz Daniluk, Adam Wujek,}
\IEEEauthorblockN{Mattia Rizzi, Dimitrios Lapridis}
\IEEEauthorblockA{CERN, Geneva, Switzerland}
}
\begin{document}
\maketitle
\begin{abstract}
%\boldmath
White Rabbit (WR) extends the Precision Time Protocol (PTP)
\end{abstract}
\section{Introduction}
White Rabbit (WR) \cite{biblio:whiteRabbitCERN}\cite{biblio:whiteRabbit} is a
multilaboratory, multicompany and multinational collaboration to
develop new technology providing a versatile solution for control and data acquisition
systems. This new technology is also called White Rabbit and provides sub-nanosecond
accuracy and picoseconds precision of synchronization, as well and deterministic and
reliable data delivery, for large distributed systems.
WR is based on well-established networking standards, extending them if needed,
to meet the requirements of WR applications. A WR network, depicted in Figure~\ref{fig:WRN},
is a Bridged Local Area Network (IEEE 802.1Q \cite{biblio:802.1Q}) that uses Ethernet
(IEEE 802.3 \cite{biblio:IEEE802.3}) to interconnect network elements and
Precision Time Protocol (PTP, IEEE 1588-2008 \cite{biblio:IEEE1588}) to synchronize
these network elements. A WR network consists of two types of network elements
that implement WR enhancements: WR switches and WR nodes. Network elements that
do not implement WR enhancements, non-WR switches and nodes, can be connected
to the WR network and they will see it as a standard PTP Ethernet LAN. WR switches
and nodes, on the other hand, can benefit from the following enhancements:
\begin{enumerate}
\item Sub-ns accuracy and picoseconds precision of synchronization between all
WR switches and WR nodes provided by the WR extension PTP (WR-PTP,
\cite{biblio:WRPTP}) and its supporting hardware, described in
\cite{biblio:ISPCS2011}\cite{biblio:TomekMSc}\cite{biblio:WRproject}.
\item Deterministic and low-latency communication between WR nodes provided by
a purposely customized and open design of the WR switch, described in
\cite{biblio:MaciekPhD}.
\end{enumerate}
Studies \cite{biblio:MaciekPhD}\cite{biblio:CesarPhD}\cite{biblio:JosePhD} has shown
that both of the above enhancements can be further extended to operate in highly reliable
manner ensuring maximum a single failure per year for a network of 2000 WR nodes.
\begin{figure}[!ht]
\centering
% \vspace{0.1cm}
\includegraphics[width=0.4\textwidth]{network/wr_network-enhanced_pro.pdf}
\caption{White Rabbit Network.}
\label{fig:WRN}
\end{figure}
Since its conception in 2008, the number of WR applications has grown beyond
any expectations. The reasons for such a proliferation of applications
are the open nature of the WR project and the fact that the WR technology is based
on well-know and well-established standards. The former encourages collaboration,
reuse of work, adaptations and prevents vendor locking. The latter allows to use
of of-the-shelf solutions (hardware/software) with WR networks and catalyzes
collaboration with companies.
What started as a project to renovate one of the most critical systems at CERN,
GMT \cite{biblio:GMT}\cite{biblio:GMTJavierPres}, is now a multilaboratory,
multicompany and multinational collaboration developing a technology that is
commercially available, used all over the world, and being incorporated into
the original PTP standard \cite{biblio:P1588WG}\cite{P1588-HA-enhancements}.
\section{Types of White Rabbit Applications}
This section describes different ways in which WR is used in end-
applications. Such applications are described in the subsequent sections and
include:
accelerators, synchrotrons and spallation sources (Section~\ref{sec:accelerators}),
detectors of cosmic rays and neutrinos (Section~\ref{sec:detectors}),
extreme laser experiments (Section~\ref{sec:lasers}),
national metrology institutes (Section~\ref{sec:timelabs}), and
power industry (Section~\ref{sec:power}.
\subsection{Time and Frequency Transfer}
\label{sec:time-and-freq}
The most basic application of WR is a transfer of time and/or frequency. The time
is provided as an output Pulse Per Second (PPS) signal and an information about the
number of seconds since the epoch. The frequency is provided as an output clock
signal (CLK) with the frequency of either 10 MHz or one of the WR base frequencies:
62.5MHz or 125MHz. The source of time and frequency in a WR network is the
Grandmaster (WR switch or node). Such Grandmaster is usually connected to a Cesium
or Rubidium frequency standard and Global Positionig System (GPS), thus providing
International Atomic Time (TAI) and frequency traceable to a
standard, both transferred from the Grandmaster to all the WR switches and WR
Nodes. The PPS and CLK can be provided to applications by WR switches
(via front panel outputs) and WR node (via output signals of an FMC
\cite{biblio:fmc-dio-5cha}\cite{biblio:fmc-dio-del}) . All of WR applications are
based on the precise transfer of time and
frequency. Yet, in practice mostly national time laboratories
(see Section~\ref{sec:timelabs}) use these signals directly. Most of the applications benefit
from functionalities that are built using the transferred time and/or frequency.
Such functionalites are described in the following subsections.
\subsection{Time-Triggered Control (TC)}
\label{sec:time-triggered-ctrl}
Many accelerators, synchrotrons and spallation sources are controlled by triggering
events in a pre-configured sequence of actions. In fact, it is a very convenient
way to control beams of particle that move at very large speeds, often close
to the speed of light. In the accelerator timing systems based on WR (Sections
\ref{sec:CERN-GMT-BST},\ref{sec:GSI-GMT},\ref{sec:JINR-GMT},\ref{sec:ESFR-GMT},
\ref{sec:CSNS-GMT}), such actions are scheduled at a particular TAI time. These
systems take advantage of both WR enhancements: synchronization and determinism.
By knowing the upper-bound latency through the WR network, the controler knows the
minimum advance with which an event can be scheduled. By having precise time
and frequency, events can be scheduled with sub-ns accuracy and picoseconds
precision.
\subsection{Precise Timestamping (TS)}
\label{sec:timestamping}
In a great numbers of applications, time and frequency are transferred in order
to timestamp accurately and/or precisely incoming signals. Such incoming signals
can be either discrete pulses timestamped with time-to-digital converters
or analogue signals that are sampled (digitized) with the distributed frequency
and associated with the distributed time.
The most demanding applications in terms of timestamping are cosmic ray array
detectors (Section~\ref{sec:detectors}) that record the time of arrival of
chaged particles in individual detector units distributed over tens of meters to tens
of kilometers. Based on the difference in the time of arrival, the trajectory of
particles are detected. In accelerators, synchrotrons and spallation sources
(Section~\ref{sec:accelerators}), timestamping are used for diagnostics and in
experiments. Being able to collerate signals in accelerators allows to recreate
the sequence of events when something goes wrong. Correlating samples in detectors
allows to coherently recreate experimental data.
\subsection{Triggers Distribution (TD)}
\label{sec:triggers-distribution}
Triggers distribution combians time-triggered control and precise timestamping
described above. In this application, an input trigger is timestamped, sent over
WR network to many WR nodes that act upon the received message simultaneously, at
a precise delay with respect to that timestamp.
The input trigger can be either a pulse or an analogue signal exceeding a treshold.
The information about the trigger, along with the timestamp, is sent over WR network
to other WR nodes, usually as a broadcast. Thanks to the deterministic characteristics
of the WR network, an upper-bound latency of the transmitted message is known for
the given hierarchy and configuration of the network. In order to generate
the trigger simultaneously in the WR nodes, the worst case latency with some
margin of error is applied. Such trigger distribution has been used to diagnose
LHC since \cite{biblio:WR-LIST} since 2013, see Section~\ref{sec:CERN-LIST}.
\subsection{Fixed-Latency Data Transfer (FL)}
\label{sec:fixed-latency}
Fixed-latency data transfer provides a well-know and precise latency of data
transfer between WR nodes in the WR network. It uses very similar
principles to the trigger distribution in Section~\ref{sec:triggers-distribution}.
In this schema, the time of data transmission is timestamped and this timestamp
is sent in the Ethernet frame with the data. When the data is received, a programmable
delay is added to the transmission timestamp and the associated data is is provided
to an application precisely at the delayed time. Such a functionality is implemented
by the so-called "WR Streamers" IP Core \cite{biblio:wr-streamers} which add a
transmission layer on top of WR and act as an fixed-latency FIFO over Ethernet.
By providing such functionality to the application, the application does not need
to be aware of time but rather process the data as it comes, knowing that all the
WR nodes in the WR network will the execute the same action at the same time.
The "WR Streamers" are used at CERN in the WR-BTrain system
(Section~\ref{sec:CERN-wr-btrain}) that distributes the value of magnetic field
in real-time.
\subsection{Radio-Frequency Transfer (RF)}
Radio-frequency (RF) transfer allows to digitize periodic signals in a WR node, send
their digital form over WR network to other WR nodes, and then regenerate them
coherently in many WR nodes with a fixed delay. Such schema is depicted in
Figure~\ref{fig:RFoverWR} and described in \cite{biblio:WR-LIST}.
\begin{figure}[!ht]
\centering
\vspace{0.5cm}
\includegraphics[width=0.4\textwidth]{applications/CERN/RF-over-WR.jpg}
\caption{Radio-frequency transmission over White Rabbit.}
\label{fig:RFoverWR}
\end{figure}
In this schema, A didigatal direct synthesis (DDS) based on the WR frequency (125MHz)
is used to generate an RF signal that is compared with a phase detector to the
input RF signal. The error measured by the phase detector is an input to an
Integral-Proportional (PI) controller that steers the DDS to produce signal identical
to the RF input. The tuning words of the DDS are the digital form of the RF input
that is sent over WR network. Each of the receiving WR Nodes uses the tuning
words to recreate the RF input by controlling their local DDS with a fixed delay.
In such way, all the WR nodes produce RF outputs that are phase-aligned with sub-ns
accuracy and picoseconds precision and that are delayed with respect to the RF
input. This schema is used currently tested in ESRF (Sectoin~\ref{sec:ESFR-GMT})
and at CERN (Section~\ref{sec:CERN-RF})
\section{Applications in Accelerators, Synchrotrons and Spallation Sources}
\label{sec:accelerators}
\subsection{European Organization for Nuclear Research (CERN)}
\label{sec:CERN}
While it was initiated within the framework of renovating CERN's General
Machine Timing \cite{biblio:GMTJavierPres}, WR found many other applications
and it is one of recommended fieldbuses at CERN.
\subsubsection{CERN Neutrinos to Gran Sasso (CNGS)}
\label{sec:CERN}
The first operational application of WR was in the second run of the
CERN Neutrinos to Gran Sasso (CNGS) experiment \cite{biblio:wr-cngs}. Two WR
networks were installed in parallel with the initial timing system, one WR
network at CERN and one in Gran Sasso. Each WR network consisted of a Grandmaster
WR Switch connected to the time reference (Septentrio PolaRx4TR
\cite{biblio:PolaRx4e} and Symmetricom Cs4000 \cite{biblio:CS4000}), a WR
switch in the underground cavern and a number of SPEC boards with FMC-DEL that
performed timestamping of inputs signal. The measured performance of the deployed
system over 1 month of operation was 0.517 ns accuracy and 0.119 ns precision with
MTIE below 1.05 ns and only 0.0003\% of values exceeding the ±0.5 ns range.
\subsubsection{BTrain over White Rabbit (WR-BTrain)}
\label{sec:CERN-wr-btrain}
In circular accelerators, the acceleration of beam by radio-frequency (RF) cavities
needs to be synchronized with the increase of magnetic field (B-field) in the
bending magnets. At CERN, BTrain is a system that measures and distributes the
value of the magnetic field (B-value) in real-time to the RF cavities,
power converters and beam instrumentation, as depicted in Figure~\ref{fig:WR-BTrain}.
While the RF cavities
simply follow the ramp of magnetic field, the power converters adjust the current
of the magnets such that the intended B-value is obtained and closing a control
loop. BTrain is essential to the operation of most of CERN accelerators, i.e.
Booster, PS, SPS, LEIR, AD, and ELENA.
\begin{figure*}[!ht]
\centering
\vspace{0.5cm}
\includegraphics[width=0.9\textwidth]{applications/CERN/BTrainUpgrade.jpg}
\caption{BTrain over White Rabbit.}
\label{fig:WR-BTrain}
\end{figure*}
The original BTrain system uses coaxial cables to distribute pulses which indicate
increase or decrease of magnetic filed. This old-BTrain is now being upgraded to
use WR network \cite{biblio:WR-Btrain-MM} for distribution of the absolute value of the
magnetic field (i.e. B-value) and other additional information. This upgraded system
is called WR-BTrain \cite{biblio:WR-Btrain}. In WR-BTrain, the B-values are transmitted
at 250kHz
(every $4\mu s$) from the measurement WR node to all the other nodes. In the most
demanding accelerator, SPS, the data must be delivered over 2 hops (WR switches)
with latency of $10\mu s\pm 8ns$.
The WR-BTtrain has been succesfully evaluated in the PS accelerators where it has
been running operationally since 2017. It is now being installed in the remaining
accelerators. By 2021, all the accelerators should be running WR-BTrain operationally
\cite{biblio:WR-Btrain-status}.
For each WR-BTrain, a separated WR network is installed that consists of 1-2
WR switches and 2-5 WR nodes.
\subsubsection{Trigger Distribution for LIST and OASIS}
\label{sec:CERN-OASIS}
\subsubsection{RF distribution at SPS}
\label{sec:CERN-RF}
\subsubsection{General Machine Timing (GMT) and Beam Synchronous Timing (BST)}
\label{sec:CERN-GMT-BST}
\subsection{GSI Helmholtz Centre for Heavy Ion Research (GSI)}
\label{sec:GSI-GMT}
White Rabbit (WR) is used as the basis for timing system at GSI Helmholtz Centre
for Heavy Ion Research (GSI)\cite{biblio:GSI}. GSI is a heavy ion
laboratory that performs basic
and applied research in physics and related science disciplines. It is located in
Darmstadt, Germany. GSI’s complex of accelerators is being extended with a new
Facility for Antiproton and Ion Research (FAIR) \cite{biblio:FAIRtimingSystem}.
FAIR will be one of the
largest and most complex accelerator facilities in the world with its biggest
accelerator of 1100m circumference. The operation of the FAIR facility requires
time-triggered actions in different sub-systems of its accelerators. This is the
responsibility of a timing system called General Machine Timing (GMT). Operation
of FAIR requires that a central controller triggers within 500us an action in any of
the 2000-3000 sub-systems. While the vast majority requires only about 1us accuracy,
many subsystems like RF, beam instrumentation and experiments require 1-5 ns accuracy
and 10 ps precision. This is achieved using WR network \cite{biblio:WR-GSI}\cite{biblio:MathiasPhD}
that consists of 300
WR switches in 5 layers and 2000 WR nodes integrated with accelerator sub-system.
The WR nodes and WR switches are connected with fibers of up to 2km length. The
required reaction time of the system is 1ms which translates into an upper-bound network
latency of 500us from the central controller to any node. The WR-based GMT timing
system already replaced the old timing system at the existing GSI facility and has
started operation in 2017. The first major beam time using the new timing system
starts in June 2018 \cite{biblio:GSI-schedule}.
\subsection{Joint Institute for Nuclear Research (JINR)}
\label{sec:JINR-GMT}
\subsection{European Synchrotron Radiation Facility (ESRF)}
\label{sec:ESFR-GMT}
\subsection{China Spoliation Neutron Source (CSNS)}
\label{sec:CSNS-GMT}
\section{Detectors of Cosmic Rays and Neutrinos}
\label{sec:detectors}
\subsection{CERN Neutrinos to Gran Sasso (CNGS)}
\label{sec:}
\subsection{Cubic Kilometre Neutrino Telescope (KM3NeT)}
\label{sec:}
\subsection{Cherenkov Detectors in Mine PitS (CHIPS)}
\label{sec:}
\subsection{Deep Underground Neutrino Experiment (DUNE)}
\label{sec:}
\subsection{Short Baseline Neutrino Physics program (SBN)}
\label{sec:}
\subsection{Large High Altitude Air Shower Observatory (LHAASO) }
\label{sec:}
\subsection{Hundred Square km Cosmic ORigin Explorer (HiSCORE)}
\label{sec:}
\subsection{The German Aerospace Center (DLR)}
\label{sec:}
\subsection{Cherenkov Telescope Array (CTA) }
\label{sec:}
\subsection{Square Kilometre Array (SKA)}
\label{sec:}
\section{Extereme Laser Experiments}
\label{sec:lasers}
\subsection{ELI Attosecond Light Pulse Source (ELI-ALPS) }
\label{sec:}
\subsection{ELI Beamline Facility (ELI-BEAMS) }
\label{sec:}
\section{National Metrology Institutes}
\label{sec:timelabs}
\subsection{Finland (MIKES)}
\label{sec:}
\subsection{Netherlands (VSL)}
\label{sec:}
\subsection{France (LNE-SYRTE)}
\label{sec:}
\subsection{UK (NLP)}
\label{sec:}
\subsection{Italy (INFRIM)}
\label{sec:}
\subsection{White Rabbit Industrial Timing Enhancement (WRITE))}
\label{sec:}
\section{Power Industry and Smart Grid}
\label{sec:power}
\begin{table*}[!t]
\caption{White Rabbit Applications}
\centering
\scriptsize
\begin{tabular}
{| p{1.15cm} | c | c | c | p{1.3cm} | p{1.3cm} | p{1.2cm} | c | c | c | p{1.2cm} |} \hline
\textbf{System} &\textbf{Facility}&\textbf{Location}&\textbf{Type}&\textbf{Reqirements}&\textbf{Status} &\textbf{Performance} &\textbf{Link lenght} & \textbf{ $<$ Sept 2018} & ~2020 &\textbf{Remarks} \\
\textbf{Name} & & & & & & &(Total distance)& \textbf{WRN/WRS/WRL} &\textbf{WRN/WRS/WRL} & \\
& & & & & & & & & & \\ \hline
CNGS & CERN & Switzerland & TS & ~1ns & Operated successfully & A:0.517ns, P:0.119ns & $<$10km (16km) & 10 / 4 / 2 & & Dismantled \\ \hline
WR-BTrain & CERN & Switzerland & FL & latency $10\mu s\pm 8ns$ & Operational (PS,ELENA) & & $<$1km & 6 / 2 / 1 & ~20 / 8 / 1 & 6 WR networks \\ \hline
Trigger distribution & CERN & Switzerland & TD & & & & & & & \\ \hline
RF & CERN & Switzerland & RF & & & & & & & \\ \hline
GMT & CERN & Switzerland & TC & & & & & & & \\ \hline
& & & & & & & & & & \\ \hline
GMT & GSI & Germany & TC & A: 1-5ns P:$<$10ps & First Beam in June 2018 & & $<$1km & & & \\ \hline
& & & & & & & & & & \\ \hline
& & & & & & & & & & \\ \hline
\end{tabular}
\label{tab:rawData}
\end{table*}
\section{Performance Enhancements}
\label{sec:}
\subsection{Temperature Compensation}
\label{sec:}
\subsection{Accuracy and Precision}
\label{sec:}
\subsection{Link Lenght}
\label{sec:}
\subsection{Link Asymmetry}
\label{sec:}
\subsection{Absolute Calibration}
\label{sec:}
\section{New Developments and Outlook}
\label{sec:}
\section{Conclusions}
\label{conclusions}
\bibliographystyle{IEEEtran}
% \bibliography{IEEEabrv,./wrApplicationsOverview}
\bibliography{wrApplicationsOverview}
\end{document}
% LocalWords: PPSi picoseconds SyncE CERN WRPTP Kconfig struct TimeInternal
% LocalWords: tstamp recv send init
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