atlas itk electronics specification component or facility ... · crate. the lv power supply...

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Specification for LV PS for ITk Strip Detector

ATLAS ITk Electronics Specification

Component or Facility Name: The Low Voltage Power Supply system for

ITk Strip Detector

Preliminary Design Report

Version: V 0.1

Abstract

This document describes preliminary technical specifications for the low voltage power

supply system providing power for the on-detector electronics of ITk strip. The

proposed power and current requirements were based on the thermo-electrical module

simulations. Note that these estimates are subject to changes as ASICs will be prototyped

and characterized.

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Revision History

Rev.

No.

Proposed

Date__

Approved

Date

Description of Changes

(Include section numbers or

page numbers if appropriate)

Proposed By:

___author___

Approved By:

reviewer

0.1 P: 10.10.2018

A:

Initial draft P:Ewas Stanecka

A:

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Table of Contents

1 CONVENTIONS AND GLOSSARY ........................................................................................................... 4

2 RELATED DOCUMENTS ........................................................................................................................... 4

3 DESCRIPTION OF COMPONENT OR FACILITY ................................................................................. 4

3.1 GENERAL CONTEXT .................................................................................................................................... 4 3.2 LV POWER SUPPLY SYSTEM DESCRIPTION ............................................................................................... 5

4 INTERFACES ............................................................................................................................................... 5

5 PHYSICAL DESCRIPTION ........................................................................................................................ 5

6 MANUFACTURER ...................................................................................................................................... 6

7 POWER ......................................................................................................................................................... 6

8 INPUT/OUTPUT ........................................................................................................................................ 6

9 DETAILED FUNCTIONAL DESCRIPTION AND SPECIFICATION .................................................. 6

9.1 SUMMARY OF THE REQUIREMENTS ........................................................................................................... 6 9.2 TECHNICAL REQUIREMENTS FOR THE PS CRATES .................................................................................. 7 9.3 TECHNICAL REQUIREMENTS FOR THE LV MODULE ................................................................................ 7

10 RADIATION TOLERANCE AND ENVIRONMENTAL CONDITIONS, OTHER SPECIAL REQUIREMENTS .............................................................................................................................................. 8

11 TESTING, VALIDATION AND COMMISSIONING ............................................................................ 9

11.1 TEST TO BE PERFORMED BY SUPPLIER .................................................................................................. 9 11.2 PROTOTYPE VALIDATION ....................................................................................................................... 9

12 RELIABILITY MATTERS ..................................................................................................................... 10

12.1 CONSEQUENCES OF FAILURES................................................................................................................ 10 12.2 PRIOR KNOWLEDGE OF EXPECTED RELIABILITY ................................................................................ 10 12.3 MEASURES PROPOSED TO INSURE RELIABILITY OF COMPONENT AND/OR SYSTEM ........................ 10 12.4 QUALITY ASSURANCE TO VALIDATE RELIABILITY OF DESIGN AND CONSTRUCTION OR

MANUFACTURING TECHNIQUES ........................................................................................................................ 10 12.5 QUALITY CONTROL TO VALIDATE RELIABILITY SPECIFICATIONS DURING PRODUCTION ............... 11

13 REFERENCES .......................................................................................................................................... 11

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1 Conventions and Glossary

PP#

Patch Panel followed by a number from 1 to 3.

Stave An assembly of several detector modules that forms one stave of a barrel for

the barrel part of the ITk Strips detector.

Petal An assembly of several detector modules that forms one wedge shaped segment

of a disk for the end-cap part of the ITk Strips detector

PS Power Supply

LV Low Voltage

HV High Voltage

EoS End of Stave card

2 Related Documents

The High Voltage Power Supply system for ITk Strip Detector

PP2 Specifications - to be prepared

3 Description of Component or Facility

3.1 General context

The ATLAS collaboration will replace the existing Inner Detector by an all-silicon detector

named the Inner Tracker (ITk) [1] for the High Luminosity LHC upgrades. The

commissioning of the new detector is foreseen for 2025-2026 and the expected lifetime of the

experiment is about 15 years from the commissioning date.

The basic unit of the ITk Strips detector is a module. Modules are mounted on bigger

structures: barrel staves and end-cap petals. Power for the modules is conditioned by power

boards mounted on each one. The End-Of-Substructure (EoS) card sitting at the end of each

stave and petal, also has a power board for its power requirements. The EoS distributes low

voltage and high voltage power from PP1 to the bus tapes. Power is then bused to each

module along the staves and petals.

The modularity of the external power supplies is driven by modularity of the detector and its

services. A unit is one side of the barrel stave or one side of the end-cap petal. Each of these

units contains one bus tape. There is one LV power supply channel for each bus tapes.

The low voltage power is supplied at 48 V from the power supplies located in the service

caverns US15 and USA15. Then the voltage is stepped down by a DC-DC converter placed

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in the Patch Panel 2 (PP2) inside ATLAS detector, to deliver 11V as measured and

monitored at the load (EoS of stave or petal). The voltage drops in the cable run from PS to

PP2 are below 1.5 V, so that main LV power supplies could be operated without remote

sensing.

3.2 LV power supply system description

There will be 1552 48 V supplies, a half of them located in each of two service caverns. 272

of these channels, serving inner barrel staves, will require twice the power of the remaining

1280 channels serving outer barrel staves and petals.

Taking into account the cables grouping as well as the grounding and shielding aspects of the

powering chain, the LV and HV Power Supplies corresponding to the same cable bundle

serving two staves or petals, must be installed in the same rack, and preferably in the same

crate.

The LV power supply requirements described in this document are based on the thermo-

electrical module simulations, and are determined for the worst case scenario conditions,

namely at the radiation induced current peak of the readout ASICs, and at the end-of-life bias

leakage current for the sensors, see [2] . Note that these estimates are subject to changes as

ASICs will be prototyped and characterized.

4 Interfaces

This component interfaces to other components listed in Table 4.1.

Table 4.1: Components which Interface to LV PS system

Name of Component Name of Component Specification

Patch Panel 4

SCT Cable type IV

Patch Panel 2

Power Supply Crate

ITk Strip Interlock system

5 Physical Description

The LV PS system will comprise LV multichannel modules installed in crates suitable for

standard 19” ATLAS 52U Racks.

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6 Manufacturer

Commercial or semi-customized commercial LV PS are considered. The specifications were

discussed with typical HEP vendors with positive feedback. Final manufacturer selection will

be done in course of Market Survey process, after prototypes validation.

7 Power

TBC: Power supplied to the LV PS crate will be determined once the module granularity

is known.

Table 7.1: Power Requirements

Name Max/Nom/Min

Vout

Nom/MaxIout

SS stave

Max/Min V for

Current Source

Other

Requirements

8 Input/Output

Table 8.1: Input and Output Signals

Name In, Out

or I/O

Type of Signal

or Max/Min

Input or Output

Impedance

Description

Interlock In TTL Signal provided by the

external ITk interlock system

9 Detailed Functional Description and Specification

9.1 Summary of the requirements

The nominal output voltage of LV channels is 48 V and maximum current is 2 A for Outer

Barrel staves and End-cap petal and 4 A for Inner Barrel staves. The LV channel have

voltage and current monitoring (1% accuracy and 8-bit resolution). Each voltage channel

contains the hardware protection that limits a maximum output current, as well as against an

over-voltage at the output of PS. No automatic measure to recover the voltage drop along the

cable (like sensing at the load or current-monitored line drop recovery) is required.

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The external interlock signals will be distributed to LV channel. The interlock signals are

TTL levels with active low (LV PS enabled) and inactive high (LV PS disabled). If the high

TTL level is missing (connection is broken) then LV PS will be disabled.

Each LV channel’s OFF-ON is controlled remotely via DCS and it’s status and diagnostics

parameters can be monitored via DCS.

9.2 Technical Requirements for the PS Crates

The LV power supply modules will be installed in crates suitable for standard 19” ATLAS

52U Racks with cooling system, located in the ATLAS service rooms USA15/US15. The

crate must fit the 19” standard in width and must have not more than 9U in height. The flow

direction of forced air cooling through the modules housed in rack-mounted crates must be

vertical upwards.

The crates must be mountable on rails in the racks, such that the position of the connector

front of the modules allows routing of the cables within the rack from the top or the bottom

of crate (closed door scenario).

A primary power supply needed within the crate to drive the modules must be modular and

exchangeable in situ.

9.3 Technical Requirements for the LV Module

The LV module has 4 or 8 channels to match granularity of the detector structures and

services. Each LV module is equipped with one (or more) microcontroller(s), providing

communication interface to the DCS via OPC UA server1 and respond to interlocks. The

power input for the power supply system is specified in Table 9.3.1, as well as compliance

with relevant regulation and electrical standards. In Table 9.3.2 detailed requirements for the

LV PS channels are shown.

Table 9.3.1:

Table 9.3.1: Power input requirements the PS System

Input voltage 240 or 400Vac

Input frequency 50 Hz, single or three phase

Power factor > 0.9 Compliant with EN61000-3-2 or similar

Inrush current < 20x In for 1ms Compliant with ETSI ETS 300 132-1 or similar

EMC compliance Compliant with EN55022 B, EN55024

1 Detailed requirements concerning PS to DCS Communications and interfaces should be prepared in close

collaboration with ATLAS DCS.

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Table 9.1.2: Technical Requirements for LV PS channels

OUTPUT

Reference potential floating relative to chassis ground for individual channels

Isolation withstand voltage 100 V +dynamic TBD

Voltage 48 ±0.5V

Voltage ramp 1 ms fixed

Maximum current 2 A, 4 A

Efficiency > 90% above 40% nominal load

Ripple and noise for f <20MHz and >10 Hz

<50 mV pp

Max power 100 W, 200 W

REGULATION, SENSING AND MONITORING ACCURACY

Remote sensing no (TBD)

Line regulation 1%

Load regulation 1%

Remote ON/OFF control yes

Voltage monitoring Yes

Current monitoring Yes

Voltage measurement resolution 8-bit resolution, 1% accuracy

Current measurement resolution 8-bit resolution, 1% accuracy

Remote interlock yes, active low , 1 channel granularity

PROTECTION

Over temperature protection yes (adjustable or fixed TBD)

Over voltage protection yes (adjustable or fixed TBD)

Over current protection yes (adjustable or fixed TBD)

10 Radiation Tolerance and Environmental Conditions, Other Special Requirements

The LV power supply system will operate in service caverns with controlled environment, at

temperatures of 20 C ± 5oC and humidity of < 70%, in normal magnetic (< 50 Gauss) and

normal radiation environment. The system will be installed in a closed racks operating with a

controlled, forced airflow cooled by heat exchangers. The maximum cooling capacity per

rack is 10 kW2. In the set-ups for the detector tests and integration, the PS system will be

2 NOTE: The SCT racks will be re-used for ITk PS system. Actual rack configuration is the following: Max.

rack power = 10kW per phase; cooling capacity= 10kW.

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operated in a normal laboratory environment. The requirements concerning environmental

conditions are summarized in Table 10.1.

Table 10.1: Environmental conditions requirements for LV PS system

11 Testing, Validation and Commissioning

All components of the LV PS system must be tested and certified by the supplier. The ITk

Strip group will perform validation and reception tests at CERN and components will be

accepted only if they pass all tests.

11.1 Test to be Performed by Supplier

All mechanical, electrical and functional tests necessary to declare component compliance to

the requirements required standards must be performed by the supplier. All tests must

comply with the approved Quality Assurance Plan prepared by supplier and approved by ITk

Strips. All equipment necessary to perform the above mentioned tests, including software,

must be procured by the supplier.

11.2 Prototype Validation

The supplier selected in course of the of Market Survey procedure will be asked to provide

prototypes. Validation tests on each individual prototyped component, will be done by ITk

Strips group. The series production can start only if all provided prototype components pass

the validation tests.

The validation tests will include:

Mechanical and electrical tests on the PS Crate (dimensions, electrical performance,

grounding and connectivity, electrical safety);

Mechanical and electrical tests on LV PS modules (dimensions, insertion/extraction

of modules, insertion of power/control/interlock connectors);

Functional tests of the LV PS system:

o Test switch on procedure, recovery from the trip;

o Efficiency measurement at no load, 50 % load, 100% load;

o Power delivery tolerance;

o Protections: over current, over voltage;

o Test with transient loads;

o AC noise measurement;

o Interlock functionality;

o Noise output from the PS;

o Noise radiation from the chassis;

o Full chain tests;

o Etc.

Operating humidity 10% to 80% RH, Non-condensing

Operating temperature 0°C to 40°C

Storage humidity 10%-80% RH Non-condensing

Storage temperature -20°C to 60°C

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12 Reliability Matters

The LV power supply system will be in service for at least fifteen years starting from the

installation in 2025/2026. LV system will be operational for more than 50% of this time.

The calculated MTTF for the HV system parts must be 100.000 hours or more.

The system tests, planned for 2022 and following years require delivery of 8% of the total

number of HV channels. All parameters of this part must be identical to these specified for

the full production.

The two years warranty is required for all system component, default for CERN purchase

(possible warranty extension options to be considered). The supplier is required to provide

long term maintenance (software updates, repairs etc.) via dedicated maintenance contract.

In case of replacement of critical components with other ones of different producers or

different types, the supplier must guarantee the same performance of the system as it was

before the replacement.

12.1 Consequences of Failures

In case of failure of LV PS system component(s) corresponding detector part will be

temporarily unpowered, until replacing broken power supply equipment.

12.2 Prior Knowledge of Expected Reliability

TBC

12.3 Measures Proposed to Insure Reliability of Component and/or System

Based on past experience with power supplies, around 10% of spares will be manufactured

for the PS changes to allow for failures during the commissioning of the system and

operations. The LV PS modules will be simply exchangeable, without special tools.

12.4 Quality Assurance to Validate Reliability of Design and Construction or Manufacturing Techniques

Components of the LV PS system specified in the this document must conform to all

specified requirements and to CERN safety instructions IS N. 23 (electrical cables), IS N.

28 (dangers due to electricity) and IS N. 41 (plastic materials), available at

https://hse.cern/content/safety-rules

Selected vendor will be asked to provide Quality Assurance Plan (QAP), reporting all

tests performed on the blocks composing the system, test methodology and conformity to

International Standards (ISO, IEC, etc.), within [TC] months from notification of contract.

https://hse.cern/content/safety-rules

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12.5 Quality Control to Validate Reliability Specifications during Production

TBC

13 References

[1] C. ATLAS, "Technical Design Report for the ATLAS Inner Tracker Strip Detector,"

2017.

[2] G. Viehhauser, " Thermo-electrical model. EDMS

https://edms.cern.ch/document/1966661/1.," 2018.