Grounding & EMC : Status and Plans
Belle II Focused Review

Dr. F. Arteche
Instituto Tecnológico de Aragon (ITA)Max Planck Institute für Physik (MPI)

On behalf of Belle II EMC (Grounding) working group

Outline• 1.Introduction• 2. GND & EMC strategy• 3.Grounding issues• 4.Cabling issues• 5.EMC issues• 6.Future plans• 7.Conclusions
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Belle II Focused Review
September 9-10, 2013, KEK, Japan1. Introduction• During last one and a half years a lot of activities havebeen carried out in order to ensure the correct integrationof Belle II electronics.
• A working group has been created to coordinate thisactivities– Grounding & EMC working group• We usually meet during Belle II general meetings in order
to coordinate and follow up these activities.
– 1st meeting Nov 2011
– 2nd meeting Jul 2012
– 3rd meeting March 2013
– 4th Meeting - July 2013

• They have been very good and useful meetings– All sub-detectors have participated
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Belle II Focused Review
September 9-10, 2013, KEK, Japan1. Introduction• During the last meeting we have organized a review ofthe grounding and EMC activities in order to verify– Grounding topologies - Belle II grounding policy– Cable layout – Cable Installation– EMC plans - Control noise issues• The review committee was created with Belle II
members and external reviewers (EMC experts)– Manobu Tanaka– C.Rivetta– G.Varner– H.G. Moser / C.Kiesling– C. Irmler / K. Hara
– Suji Uno– S. Korpar– I.Adachi– A. Kuzmin– P.Pakhlov/L.Pillonen– Yutaka Ushiroda– F.Arteche• Many thanks to all of them
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Belle II Focused ReviewSeptember 9-10, 2013, KEK, Japan1. Introduction• The review was a very good overview of sub detectors
activities on these topics.
• We have made a lot of progress since first meeting– Big effort from everybody• It has helped us to detect first incompatibilities before
installation and commissioning.
• This is only one more step to full system integration– The discussion has only started .......

• The review committee has prepared a report withthe most important issues of the meeting• During the next slides I will summarize:– Grounding and EMC activities.
– Main topics and conclusions from this review
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Belle II Focused Review
September 9-10, 2013, KEK, Japan2. GND & EMC strategy
CsI EM calorimeter (ECL)

RPC μ & KL counter:
scintillator + Si-PM (forend-caps) (eKLM-bKLM)

Solenoid
SVD (Silicon VertexDetector)

PXD (DEPFET),
PI barrel / PI Endcap
TOP+A-RICH
Central Drift Chamber(CDC)

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Belle II Focused Review
September 9-10, 2013, KEK, Japan2. GND & EMC strategy• The main goal of Grounding & EMC integration
strategy is to ensure the correct performance of BelleII experiment.
– Ensure the compatibility in each sub-system– Ensure the compatibility among units – sub-systems• It establishes a safety margin• EMC integration strategy has three parts:– Grounding issues– Cabling issues– EMC issues

Compatibility

Compatibility

SUB1
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SUB2

Belle II Focused Review
September 9-10, 2013, KEK, Japan

Compatibility

3. Grounding• What is a ground ?
– It is a reference : Uniform reference voltage at any frequency– It is a structure to bypass currents• Fault (short circuits ..)• Noise• Reasons for Grounding– Safety– Equipment protection– Equipment performance• Golden rule:– “Make the system safe and then make it work ”• Several recommendations were made.
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Belle II Focused Review
September 9-10, 2013, KEK, Japan

3.1 Grounding Topologies• Most of the grounding topologies has been presented– Multipoint ground– Floating PS units (LV)• It is time to define a common topology for all subdetectors• First “hot” areas have arisen– Grounded vs Floating (FEE)– Performance vs Safety (HV)

• Safety issues have become a priority concern– Belle II electrical safety requirements• KEK electrical safety rules (Coordination)– They may have an impact on the design
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Belle II Focused Review
September 9-10, 2013, KEK, Japan

3.1 Grounding Topologies
PXD• Multipoint GND using
cooling blocks• LV floating power
supply– DC-DC converters• Multipoint GND at DOCK box– DOCK connected to CDC(detector structure)• Isolated LV – DC-DC• Non Isolated HVSVD– Gnd via resistors• FDAC – Differential Transmi.
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Belle II Focused ReviewSeptember 9-10, 2013, KEK, Japan

3.1 Grounding Topologies• Multipoint GND• Isolated LV• Non-isolated HVTOP– 100/200 ohms
common ground atFEE• LV shields connected
locallyARICH
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• Plan to ground at the detector
side – support structure• LV, HV, Bias, DAQ cables
connected to the detector• Signal processing done at thefront-end board shielded.
• Pick-up noise not observed

Belle II Focused Review
September 9-10, 2013, KEK, Japan

3.1 Grounding Topologies
bKLM
Groundingtopology“Single-point” at eachdetector module(multipoint)

Groundingconnections

AC ground at detector,
DC ground at readoutcrate; HV DC ground atpower supply– It is planned to use the same gnd
scheme as for Belle. (good results)– No connect:– Mech.structure - FE board– Connection: FE amp gnd frame– Shield connected 1s
Belle II Focused Review
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September 9-10, 2013, KEK, JapanECL

3.1 Grounding Topologies• It proposes an isolation groundphilosophy.
CDC• It required to be separated from BelleII structure, BPID, SVD and others.
• Signal ground connected to:– The backward end plate in the CDC– Through the power modules in theelectronics hut.

• High voltage ground may bedisconnected from the forward endplate.

• Grounding topology still open
• Some test set-up are ready fornoise measurements:• They plan to study several
ground topologies.
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Belle II Focused Review
September 9-10, 2013, KEK, JapaneKLM

3.2 Grounding summary• The sub-detectors have presented different gnd strategies••••– Locally , floating, multipoint ,…
A general grounding policy should be defined.
Even in sub-detectors that are intrinsically immune to noise,grounding should be coordinated in order to avoid EM radiation toneighbors.
– Special attention should be paid to large floating system
due to the creation of uncontrolled noise paths.
A detailed definition of electrical schematics and grounding
techniques may be used to start coordinating the installationof sub-systems– These activities will be carried out by a group of people (Belle II)
It is recommended to evaluate the grounding technique at
prototype level before installation– It will help to take corrective actions in advance

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Belle II Focused Review
September 9-10, 2013, KEK, Japan

4. Cabling issues• There are two elements that play an important role in
the electromagnetic noise level of any experiment:– Cables– Racks• They may cause many EMC problems:– Cable radiation– Cable susceptibility– Malfunctions due to high electronics density• The EMC effects of this type of elements may bedecreased by design ( layout and connectivity)– Some recommendations were presented– They may be implemented wherever possible.
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Belle II Focused Review
September 9-10, 2013, KEK, Japan

4. Cabling issues• Cables and racks components of different EMC
categories should be laid separately whereverpossible

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Belle II Focused Review
September 9-10, 2013, KEK, Japan

4.1 Sub-detector cabling• The cable layout and power levels of each subdetector have been discussed during the meetings.
• There is a wide variability of different options– Type of cable• Some of them are new• In some cases it is planned to use Belle I cables– Power levels• KV, V, Signal , power …

• Common cable channels have been shown– There are some areas that need to be analyzed indetail to avoid interference problems• Some cables are shielded and others not at all
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Belle II Focused Review
September 9-10, 2013, KEK, Japan

4.1 Sub-detector cabling

PXD

SVD
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Belle II Focused Review
September 9-10, 2013, KEK, Japan

4.1 Sub-detector cabling

CDC• Definition of cable power
levels– +5.5, +3.8, +2.0,+1.5

ARICH
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Belle II Focused Review
September 9-10, 2013, KEK, Japan

4.1 Sub-detector cablinglayoutExit radially from the magnet
to readout crates nearby on
perimeter of magnet

levels

12V, 5V, 6kV , -3.5kV

Types

Unshielded twist-n-flat signal
cable, RG-59 HV cable

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Belle II Focused Review
September 9-10, 2013, KEK, JapaneKLM

4.2 Cabling summary• The cable layout and power levels of each sub-detector havebeen partially presented• Some areas are common to different sub-detectors and mix
different types of cables – Detail analysis is required• Attention should be paid to cable shield as well as noise
sources.
– Interference evaluation: Noise sources vs type of cable• A collection of safety rules beyond the ampacity of the cables
should be defined and communicated to all sub-detectors– Noise & Transients– fuse coordination , electronic protection, de-rating cable ampacity
for cable bundles• It is recommended to create a committee that reviews andenforces that the cable and wire layout complies with rules– Belle II and KEK members
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Belle II Focused Review
September 9-10, 2013, KEK, Japan5. EMC issues• Analysis & tests to ensure the compatibility level
among noise sources and victims have started• This noise control is being tackled at two levels– Noise emissions analysis• Noise emission test (conducted and radiated)– Noise immunity analysis• Signal circuit analysis– It will help to define grounding topologies• Noise Immunity test
– Evaluate grounding topologies– Ensure the compatibility of the FEE

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• Subsystem evaluation: Signal to noise
quantification Belle II Focused Review
September 9-10, 2013, KEK, Japan

5.1 EMC issues - Emissions• One of the most important noise sources in Belle II are thepower supplies.
– Several of them have been developed with DC-DC• They have EM emissions– Radiated– Conducted Emissions• The spectra content is very closely related to :– Switching frequency - Topology– Few kHz up to MHz• The emission level of the power supply has to becoordinated:– Sub-detector level– Experiment level
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Belle II Focused Review
September 9-10, 2013, KEK, Japan

5.1 EMC issues - Emissions
60
CM DCDC5
DIF Steering ST4V35040dBA

3020100-10-20
410PXDRadiated - H60dBA / m40

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510610Frequency

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Belle II Focused Review
September 9-10, 2013, KEK, Japan

510610Frequency710

5.2 EMC unit analysis: Noise immunity• Are the PS noise emissions (or other) compatible with the FEE ??
– Do we have enough safety margin ?

• Noise sources that deteriorate the FEE performance are:– Intrinsic thermal noise– EM contribution detector – FEE – PS - others

na(t)  nth(t)  nin(t)  n ps(t)  • This noise defines the minimum signal level that the FEE canprocess – Thermal noise dominant effect• EMI contribution characterization important• The characterization of EMI contributions may be carried out via :– Modeling and simulation of system– Immunity tests on prototypes• The main goals of this EM characterization are:– Evaluate grounding topologies– Ensure the compatibility of the FEE– Subsystem evaluation : Signal to noise quantification
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Belle II Focused Review
September 9-10, 2013, KEK, Japan

5.2 EMC issues - Immunities

ECL
System Verification

PXDbKLM
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Signal circuit analysis
Belle II Focused Review
September 9-10, 2013, KEK, Japan

5.3 EMC summary• Analysis and test to ensure the compatibility level amongnoise sources and victims has started .
• The noise control is tackled at two levels– Noise emissions– Noise immunities• Some subsystems have presented EMC plans and tests
but it is still necessary to prepare a detailed global plan.
• This plan will help to define sensitive frequencies that
may interfere among sub-detectors• Some of the immunity tests will be very useful for final
grounding topology of each sub-detector– Still under development
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Belle II Focused Review
September 9-10, 2013, KEK, Japan6. Future Plans• Electrical safety rules for Belle II need to be clarified.
• An overall "Belle II" grounding diagram and moredetailed EMC plan should be prepared.
– Each sub-detector system will provide a very detailed/grounding overview (simplified schematic) & EMC plans• It will be necessary to establish a grounding and EMC
responsible at KEK in order to follow the indications.
– This person may act now as a link person Belle II - KEK• It is planned to follow up all plans in order to define
global aspects of the Belle II integration– Cabling (Short term)– Grounding (Short-medium term)– EMC (long term)
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Belle II Focused Review
September 9-10, 2013, KEK, Japan

7. Conclusions• A general overview of the status and plans of thegrounding and EMC issues has been presented• EMC & grounding activities started one and a halfyears ago
– All sub-detectors have been involved– Several meetings were held

• On July , we had a GND & EMC review at VPI, USA• This review has produced a significant step forward– Groundings configuration– Cables layout– EMC issues• This is only the beginning of a long work.
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Belle II Focused Review
September 9-10, 2013, KEK, Japan