GTS, Global Trigger and Synchronization system

Orsay, 10 december 2009, for the selection process of the trigger and synchronization system for nuclear physics experiments in GANIL (SPIRAL2) Joël Chavas

GTS

Trigger and synchronize : AGATA + ancillaries

Outline

• GTS – Main features • GTS – Hardware / software • GTS – Status and characteristics

The DAQ in AGATA

GTS – Function

• Provides the global clock • Handles centrally all trigger requests • Transport medium for trigger activity • Equalizes downlinks

– No calibration run required • Provides the absolute time (48-bit counter)

GTS – Structure

Trigger processor Root

Leaf

Leaf

Fanin- fanout

Leaf

Leaf

GTS – AGATA requirements

• Individual trigger requests – 50 kHz • Trigger validation – 1 MHz (Mult. 1) • Trigger validation – 300kHz (Mult. 30) • Repeatability of the phase skew on the sub-ns

scale

GTS – Originality and novelty

• Digital trigger system • Replaces analog triggers – without dead-time • Optical fibers, to transmit clock and trigger events • Modularity

Hardware

• Trigger processor : – a commercial card inside a PCIexpress slot of the computer

• GTS card : – Mezzanine – ATCA card in development

• Links : – Optical links – Mezzanine connectors

GTS card

FPGA

PLL

TDC

mux

DELAY

MGT optic M

trigger bus

GTS mezzanine

XXX

GTS mezzanine

GTS mezzanine – on LLP carrier GTS

GTS

GTS mezzanine – On LLP carrier

GTS

Firmware / software

• Trigger processor : – edk project, home made slow control through

PCIexpress • GTS :

– edk project, embedded software (vxWorks) – slow control through udp/ip

How it works : a modular approach

GTS tree

Trigger processor

vhdl trigger cores

Trigger processor – structure

Online sorter

Multiplicity Partition 0

Multiplicity Partition 1

Multiplicity Partition 4

Multiplicity Partition 5

Multiplicity Partition 2

Multiplicity Partition 3

Multiplicity Partition 6

Coincidence Validation broadcast

Multiplicity Partition 7

Trigger processor

• Partition coincidence – Ex : Mult(Ge) ≥ 4 and Mult(Ancillary) ≥ 1 after 5µs – Delayed multiplicity window : clock precision

GTS tree – General

• A unique hardware for all nodes • A unique firmware for all leaves • A unique embedded software for all nodes

GTS tree – Clocks

• Clock recovered from gigabit optical links • Clock cleaned by external PLL • Downlink times are measured • Downlink times are equalized through a FIFO and

an external delay line

GTS tree – Alignment

combinatorial

combinatorial t1

combinatorial

clocked t2

downlink

tdownlink = t2 – 1/2 × t1

GTS – Communication with carriers

Trigger cores

• Handle all trigger activity • Purely vhdl • Uplink :

– Trigger requests – Periodic idles

• Downlink : – Trigger validation – Absolute time – Synchronous command

• No dead-time

Root

Leaf

Leaf Leaf

Leaf uplink

downlink

Measurements – Jitters

p-p jitter (ps)

clk 70

leaf-leaf 200

leaf-root 170

Measurements – Skews

Max (ps)

phase alignment +/- 250

phase repeatability +/- 50

Measurements – latencies

• Local latency : hundreds of ns • No dead-time, except for a technical 2 µs one • GTS tree latencies :

– Max = 12 µs (4-layer tree) with trigger processor • Depends on idle rate and delayed coincidence

– 7 µs without trigger processor – 2 µs added at each FANIN-FANOUT layer

GTS commissioning : november 2009

• 4-layer GTS tree • 7 leaves (6 for germanium detectors, 1 for

ancillary detectors) • 2 partitions (germanium detectors and ancillary

detectors) with two decision equations used : – Mult(Ge, 3,+0) – Mult(Ge,2,+0) + Mult(Anc,1,+2µs)

• Technical trigger validation rate : 2 MHz

Trigger processor -- Status

• 2 multiplicity partitions implemented on a FX100 • Firmware done for 8 partitions – to be

implemented on a more powerful hardware • On-line reconfiguration through a pseudo-C

configuration file • GUI based on ncurses library

GTS tree -- Status

• Done : firmware, embedded software, host server software

• Under development : python-based GUI • ATCA card development

GTS hardware – Status

• V2 : 4 complete GTS cards + 1 GTS that can be used only as root

• V3 : 20 produced and tested • V3 : 10 under production for june 2009 • Comments :

– Production is not the problem : testing and support are the problem

– Stand-alone GTS card : no support is needed – GTS tree : support is needed

Discussion and future needs

• Ancillaries and the GTS tree latency • Feeding the root and the leave with an external

clock – links with BUTIS? • Customization (software) of the trigger processor

– Physics is done on the trigger processor

Work load

• Roberto Isocrate (hardware) • Damiano Bortolato (firmware/software GTS tree

prototype) • Joël Chavas (firmware/software/commissioning GTS tree,

testing) • Luciano Berti (trigger processor) • Marco Bellato (trigger cores, conception, organization) • Dino Bazzacco (validation)

Conclusion

• GTS : an innovative digital trigger system • Successful commissioning with the ancillary

detectors included : november 2009