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