Jefferson Laboratory Hall A SuperBigBite Spectrometer Data Acquisition System

Alexandre CamsonneAPS DNP 2013

October 24th 2013 Hall A

Jefferson Laboratory

SuperBigbite Spectrometer Data Acquisition 2

Outline

• SuperBigbite Spectrometer• Experiments• Shower trigger• Hadron calorimeter digital trigger• GEM• Fastbus • Conclusion

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SuperBigbite Spectrometer Data Acquisition 3

SuperBigBite Spectrometer (SBS)48D48 dipole

• Large dipolemagnet

• Installation inHall AJeffersonLaboratory

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SuperBigbite Spectrometer Data Acquisition 4

SuperBigBite experiments• 4 approved experiments

• GEp5 : Proton Form FactorSBS used as proton focal planewith Hadron calorimeter as polarimeter

• Neutron form factor GEn and GMnSBS used as sweeper magnet for Hadron Calorimeter as neutron detector

• TransversitySBS usedto detectpions

Hadron calorimeteras neutron detector

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SuperBigbite Spectrometer Data Acquisition 5

SuperBigbite Spectrometer GEp 5 Focal Plane Polarimeter setup

Most demanding experiment in terms of rate and background ~ 1039 cm2.s-1

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SuperBigbite Spectrometer Data Acquisition

6

Background rate vs. cut on deposited energy (MC studies in progress)

Calorimeter Rates

HCAL ECAL

Electron rate estimate w/2.5 GeV threshold (73% of Eelas): ≈ 200 kHz

Hadron rate estimate using SLAC & DESY data, Wiser code:w/4.5 GeV threshold: ≈ 1.5 MHz

≈ 9 kHz coincidence ratew/ 30 ns window

NB: Goodresolution≈ 16%/ÖE

From Hall A Real Compton Scattering experiment

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SuperBigbite Spectrometer Data Acquisition 7

DAQ concept• Hybrid Fastbus and pipelined electronics• Level 1

– ≈100 ns latency by analog summing and discrimination– Generated by electron arm (≈200 kHz rate)– Gate for Fastbus & non-pipelined VME for BigCal

• Level 2 : coincidence proton in HCAL triggered by ECAL– Assume up to ≈1.8 μs latency ( L2 800 ns max + Fast Clear 1 μs)– 9 KHz with 30 ns coincidence windows– FPGA-based coincidence logic using geometrical constraints reduction by

factor 5 ≈ 2 kHz physics DAQ rate

– Fast Clear FB & VME after L2 timeout

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SuperBigbite Spectrometer Data Acquisition

8

First level electron trigger from Shower

Sum of 8

Summing modules 8 to 1 and linear fan 4 to 1 = sum of 32

Threshold on

group of 32

Split signals to have overlapping

sums

Trigger is OR of allgroups of 32

BigCal trigger

200 KHz10/24/2013

SuperBigbite Spectrometer Data Acquisition 9

L2 Hadron calorimeter proton trigger

• New Hall D type JLAB Electronics– Under development by JLab Electronics and DAQ group– Fully pipelined– 200 kHz L1 trigger rate capability– Synchronous trigger distribution, 250 MHz ref. clock– VME64x front-end crates with support for

• High-speed readout modes (2eVME, 2eSST) up to 200 MB/s• On-module event buffering - up to 200 events• Gigabit uplinks to event builder

– CODA 3 software– Will use some of this technology + custom modules

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SuperBigbite Spectrometer Data Acquisition

10

Digital Hadron Calorimeter HCAL Trigger

12-bit pipelinedFADCs

CPU

TI

SMART

TRIG

12-bit pipelinedFADCs

.

.

.

11 x22 modules242 blocks

• All channels continuously digitized at 250 MHz

• Compute all 4x4 sums• Generate trigger if sum above threshold

Electron trigger

Coincidence Electron protonWith geometrical correlation

~2KHz10/24/2013

11

e’-p Kinematic Correlation11 x 22 HCAL blocks 20 x 76 ECAL blocks

(CDR section F.3)

SuperBigbite Spectrometer Data Acquisition

Using geometric correlations from elastic kinematic one can reduce final rate by a factor of 5 and

tracker data by at least a factor of 3

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SuperBigbite Spectrometer Data Acquisition 12

FPP Tracker layout512

2560

2048

128 channels

25 ns25 ns

• APV25 40 MHz sampling pipeline chip

• 192 samples memory depth

• 128 channels per chip• Can transfer 1 or 3 samples

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SuperBigbite Spectrometer Data Acquisition 13

MPD APV25 INFN readout• Multi Purpose Digitizer• FADC• GEM readout• Up to 16 APV by board

2048 channels / board• Latency :tAPV = 141 x number_of_sample / 40 MHz = 11 us

• Buffered• VME320 board• Adapted software with JLAB Intel VME

controller• Start optimizing for performance

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SuperBigbite Spectrometer Data Acquisition 14

Fastbus

• Reuse older available electronics for rest of detectors– Limitation : • encoding 9 us for 1881M ADC, 7.6 for 1877S• 40 MB/s

– Use several crates to readout modules in parallel• Poor man’s pipeline– Use several modules to reduce encoding dead

time

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SuperBigbite Spectrometer Data Acquisition 15

Module flippingTrigger

SupervisorTrigger

PMT

L2

L1A

Front End Busy

Fast Clear

Shift register

Signal is split analog signal

and sent several boards.Readout and trigger

are interleaved

Fast

Cle

ar

L2A

L2A

Shift register

ADCs or TDCs

Up to 200 KHz L1A rate = 5us

• Fastbus– ECal

• 1800 calorimeter channels

– BigBite• 550 Cerenkov channels• 243 Shower/preshower• 180 timing scintillators

– 3328 scintillator channels

– 16 crates– 6 Power Supply

New CODA 3 electronics improve deadtime by 30%

19 controller, 28 crates, 12 PS on hand

22528 TDC and 6208 ADC channels tested

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SuperBigbite Spectrometer Data Acquisition 16

Conclusion

• SuperBigBite DAQ is designed to handle up the rates for Gep 5 :– 200 KHz electron rate– 2 MHz of hadron rate in HCAL– Coincidence and geometrical correlation gives ~2 KHz of

trigger rates• Readout with GEM with multiple samples allow to

clean up background offline in trackers• Reuse of Fastbus allows to be ready to run early at

reduced cost with reasonable performance

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