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The sROD Module for the ATLAS Tile Calorimeter

Phase-2 Upgrade Demonstrator

The ATLAS Tile Calorimeter

Introduction

The LHC is a particle accelerator designed to handle

proton-proton collisions at up to a center of mass energy

of 14 TeV (center of mass). ATLAS is one of its main

experiments. Being a general purpose particle detector, it

is composed of various sub-systems: the inner detector for

tracking the particles, the calorimeters for measuring their

energy and position and the muon spectrometer for the

detection of muons.

TileCal is the hadronic barrel calorimeter for ATLAS and it

provides accurate energy and position measurements for,

hadrons, jets, taus and missing transverse energy.

ATLAS TDAQ

The Trigger and Data Acquisition System (TDAQ)

manages the hardware resources for the read-out of the

detector. It defines three domains in the dataflow, called

levels of trigger, which establish different methods and

rates for the selection of events,

Front-end electronics

TileCal is built in steel as absorber medium and

scintillating plastic tiles as active material. The tiles are

arranged in cells that produce light in the interaction with

the particles. The light produced in a cell is converted to

an electrical pulse in a photomultiplier tube (PMT), and

digitized on a subsequent step, forming a TileCal read-out

channel.

Tilecal is divided in four cylindrical partitions: EBA, LBA,

LBC, EBC which are azimuthally segmented in 64

instrumented modules each hosting up to 48 PMTs. The

complete read-out of the calorimeter is formed by 9856

channels which are serialized and transmitted at 640

Mbps to the back-end electronics located in a separated

cavern.

Back-end electronics

The Read-Out Driver (ROD) plays a key role in the data

acquisition chain. It is responsible of the deployment of

first processing algorithms to data in real time (online

algorithms). It receives the data from the front-end links

deserializes and routes them to its two Processing Unit

(PUs) daughter-cards that are populated with commercial

DSPs. These DSPs compute the reconstruction of the

energy and the time as well as a quality factor, with a

maximum latency defined by the Level 1 trigger rate (100

KHz). The Output Controller FPGAs receive the

processed events and packages them into ROD data

fragment format. Finally, the resulting data fragments are

serialized and transmitted to the Read-Out Buffers,

located on the Level 2 trigger.

F. Carrió1, A. Ferrer1,V. Castillo1, Y. Hernández1, E. Higón1, L. Fiorini1, B. Mellado2, L. March1, P. Moreno2, R. Reed2, C. Solans3 A. Valero1, J. A. Valls1

On behalf of the Tile Calorimeter System

1- IFIC (Spain) , 2- University of the Witwatersrand (South Africa), 3 - CERN (Switzerland)

Poster presented on the TWEPP 2013 Topical Workshop on Electronics for Particle Physics

TileCal Upgrade Demonstrator ProgramTileCal Phase II Upgrade

In order to cope with the luminosity increase by a factor of ten

on the LHC at 2022, an upgrade is foreseen for the most part

of the readout electronics. The new architecture will provide:

• Full digital L1 trigger

• Complete detector data sent to back-end every bunch

crossing (25 ns)

• Redundant data links to back-end

• Redundant power supplies

• Higher radiation tolerance

A remarkable difference resides in the fact that the L1 trigger

decision will be made upon data stored in the ROD. This

change on the L1 boundary, together with the added

redundancy on the data links, imply a considerable increase

of the detector output bandwidth.

sROD Demosntrator

TileCal Upgrade Electronics Demonstrator

In order to test the future architecture, a demonstrator

program is being developed for its installation at the end of

2013 shutdown. It comprises all the front-end and back-end

electronics needed for the readout of 1 module. Electronics

within this module will be hybrid in order to maintain

compatibility with the present system, and will provide both

analog and digital trigger signals.

The sROD demonstrator requires:

• Reception of data from 48 PMTs@40 MHz

• Pipeline and de-randomizer memories

• Reconstruction algorithms

• Data transmission to ROS

• Control and configuration of front-end electronics

• Trigger preprocessing and transmission for L1 Calo

sROD Demonstrator Board Design

The LHC

ATLAS

The ATLAS Trigger System

Present architecture

DAQ

Future architecture

Virtex7XC7VX485T-2FFG1558

Kintex7XC7K420T-2FFG901

Parallel Flash

DDR3 512 MB

Power Modules

Front-End LinksQSFP+

QSFP+

QSFP+

QSFP+

ETH

USB-UART

MMC

SFP+

CLOCKUNIT

Input

MiniPOD

Output

MiniPOD

AM

C co

nn

ector

Parallel Flash

DDR3 512 MB

IPMI JTAG

12V

1.0 V

1.5 V

1.8 V

1.2 V

3.3 V

sROD block diagram

Optical Connectors

Four QSFP connectors, an input and an

output MiniPOD and an extra SFP+

provide the board with a total input and

output bandwidth of 290 Gbps.

FPGAs

Present Upgrade

Total BW 165 Gbps 20 Tbps

Nb fibers 256 4096

Fiber BW 640 10 Gbps

ATCA framework

The sROD demo board will be working in an ATCA

equipment framework. The Chassis is a SYS6000

platform, with six horizontal slots and a dual star

topology backplane. The data transfers between

blades through the backplane are managed by a shelf

manager integrated in a switch. The 4500 is an ATCA

computer module allows the user direct access to the

backplane. Besides, there is a ATCA-1200 carrier,

which provides mechanical support for AMC

modules. It also provides power distribution and high-

speed communication to the RTM, to the backplane

and between AMCs.

Mechanical design

The sROD demo board is AMC

standard compliant with a double mid-

size AMC form factor (180.6 mm x

148.5 mm). It can be plugged as a

mezzanine into an ATCA carrier or

directly to the back plane in a uTCA

crate. An integrated edge connector

has been chosen to achieve a more

compact design.

Double-mid size AMC

Layout and PCB Design

This is a real size picture of the

layout of the PCB. The design is

now in routing process. The sROD

includes around 1200 components,

requiring high integration levels. The

critical areas are the FMC HPC

connector with 400 pins and the two

high density package FPGAs: the

Kintex-7 with 900 pins and the Virtex-

7 with 1556 pins. Also on the power

section six 144 LGA packages are

used for the DC/DC μModule

regulators.

The stack-up has been carefully

selected to fulfill the high-speed

design requirements. A special

dielectric (NELCO 4000-13 SI) has

been chosen for optimal values of

dielectric constant (3.2 @ 10 GHz)

and dissipation factor (0.008 @ 10

GHz). Using 8 layers for power and

grounding and 6 layers for signals,

the PCB has a total thickness of 1.6

mm, making it this way AMC

standard compliant.

IPMI Tools and TileIpmiGUI

The IPMI is a microcontroller board that

establishes connection between the

ATCA modules and the shelf manager for

providing basic services as power and

monitoring functionalities. The OpenIpmi

is an open-source library that interfaces

software to the IPMI. A specific graphical

interface for the demonstrator has been

designed based on OpenIpmi and Qt.

tools

IPMI

module

Virtex-7 Kintex-7

LEs 485 k 480 k

MGTs .. 48 24

DSPs 2800 1920

BRAM 37,080 kb 34,380 kb

Quad-QSFP caseMiniPODs

ROD board

Mezzanine PU

ATCA Carrier

ATCA System

sROD board layout sROD stack-up