BB / SBS Front-Tracker GEM & Electronics E. Cisbani / INFN-RM-Sanità P. Musico / INFN-GE and the other JLab12 members of Catania, Bari, Genova ed Rome-Sanità involved in the Front-Tracker GEM Project SBS Collaboration Meeting 7-8/July/2014 - JLab 7 J u l y 2 0 1 4 - J L a b S B S C o l l . M e e t i n g - F r o n t T r a c k e r G E M 1 • Overview • Production, latest improvements • Analysis of DESY test beam data • Tracking algorithm and first simulated results • Project status • MPD Electronics status
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BB / SBS Front-Tracker GEM & Electronics E. Cisbani / INFN-RM-Sanità P. Musico / INFN-GE and the other JLab12 members of Catania, Bari, Genova ed Rome-Sanità.
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SB
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EM
BB / SBS Front-Tracker GEM & Electronics
E. Cisbani / INFN-RM-Sanità
P. Musico / INFN-GE
and the other JLab12 members of Catania, Bari, Genova ed Rome-Sanità
involved in the Front-Tracker GEM Project
SBS Collaboration Meeting
7-8/July/2014 - JLab
7 July 2014 - JL
ab
1
• Overview
• Production, latest improvements
• Analysis of DESY test beam data
• Tracking algorithm and first simulated results
• Project status
• MPD Electronics status
SuperBigbite Spectrometer in Hall A
Background:
photon (250-500 MHz/cm2)
charged (160-200 kHz/cm2)
7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM 2
Large luminosity
Moderate acceptance
Forward angles
Reconfigurable detectors
Large luminosity
Moderate acceptance
Forward angles
Reconfigurable detectors
Front tracker reused in BigBite
Physics:Nucleon Form FactorsSIDIS – TMD’s... Nucleon structure
Workforce and funding
*) one mechanical engineer
**) electronic engineer
INFN/Funding:
• Prototyping and Production (2008-2014): 800 kUSD
• Production and Maintainance (2015-2017): ~50 kUSD/year
7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM 9
AIDA-EUDET support
Spacers shadow
Spacer shadow of ≈ 2 mm
→ 2.2% of total dead area of a single GEM module
(Cluster finding not optimized for spacer border)
7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM 10
Maskedchannels
Spacer
Spacer
Cluster distributions of 9 cumulated runs
SBS GEM Test: typical event (single module)
y - Strip
x - Strip
T0 (A0)T0+125ns
T0+25ns(A1)
Combination of T0,
T0+25ns, T0+50 ns
Fit of hitsignal
evolution
cluster
Readout dual layer(x bottom and y top) strip plane
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T0+50ns(A2)
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x
y
x/y
clustercharge
max stripcharge
beamposition
clusterwidth
max peaksample
#clusters
SBS GEM Test: measured quantities (run 499)
Note: beam cross-section ≈ 3x2 mm2, approx. 30% with 2 or 3 hits in beam pulse
7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM 13
x
y
x/y
Integral Start time (t0) Leading Const. Trailing Const. Chi2
SBS GEM Test: signal evolution fit (run 499)
6 sample fit!
tau0 ≈ 20 ns, tau1 ≈ 90 ns, RMS(t0) ≈ 4-5 ns
SBS Coll. Meeting - Front Tracker GEM
Time spread < 5 ns!
GEM Beam Test / Time resolution• Excellent (surprising ?) start time spread (from fit) < 5 ns• expected at the level of 25/sqrt(12) ≈ 4 ns (in case of negligible
contribution from electron drifting in GEM)• x/y start time reasonably correlated• no apparent effect of MPD clock synch• time spread depends on choice of APV latency (see next slide)
147 July 2014 - JLab
Test beam pulse period 160 ms,multiple of APV clock period
Simulated Start Time Reconstruction
7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM 15
Reconstructed Start Time (t0)
Error on t0
Chi2 of the fit
Zoom
Use double exponential function to fit 6 samples extracted with uniform random jitter (±12.5 ns) and poissonian amplitude distribution + gaussian noise.
Optimal latency setting:
first sample around the beginning of the signal
GEM Beam Test: Spatial Scan – Start Time
Gas flow rate: 54.3 ccm (0.5V/h)
• Peak Sample• Start Time (fit)
Look reasonably consistent
7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM 16
Peak Sample vs V/h:
2 V/h: 1.2 ±0.4
1 V/h: 1.2 ±0.4
0.5 V/h: 1.3 ±0.5
7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM 17
GEM Beam Test: Spatial Scan – Start Time
Start time increase slightly(but within uncertienties)
Start time basically constant or sligtly decreasing (opposite to y ?)
GEM Test Beam: spatial uniformity – Charge Sharing
Charge asymmetry = 2 (Cx-Cy)/(Cx+Cy) ≈ 0.4÷0.5
7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM 18
y
x
HV=4100Ar/CO2=70/30
→ x/y Charge Sharing ≈ 1.5-1.6
Charge asymmetry spread ≈ 0.3
NOTE: some x/y hits can be not correcly associated or have pileup due to events with 2 or 3 particles/pulse
7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM 19
GEM Test Beam: spatial uniformity – Hit Cahrge
Reconstruction Efficiency vs #Event
7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM 20
Efficiency holes in some of the runs: beam instability ?
Lost synch with trigger ?
Good run
Analysis work in progress, recently master student from Catania joint.
TBD◦Multiboard block transfer◦Analyze use of fiber optic protocol
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MPD v 4.0 VME interface testing2eSST cycles tested with STRUCK
SIS-3104◦2eSST supported by new firmware
release◦Readout speed measured by software:
100 transfer 4MB each. Data integrity checked for each block.Speed limited by SIS3104 2Gb/s fiber connection
◦Bus speed is measured directly on VME bus
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CYCLE DATA period Bus Speed Readout Speed
2eSST160 6 ck = 54 ns (3s/3h)
142 MB/s 117 MB/s
2eSST267 4 ck = 36 ns (2s/2h)
213 MB/s 124 MB/s
2eSST320 3 ck = 27 ns (2s/1h)
284 MB/s 124 MB/s
Event Builder Implemented multi event block structure as
suggested by DAQ people.Native data width: 24 bit, packed to 32 bit on 64
bit boundary for efficiency. Implemented 128MB FIFO data buffer using DDR2
SDRAM.Quite complicate machinery used to arbiter read
and write to/from DDR2.Output can be read in 32/64 bit format in any of
the supported VME cycles, including 2eSST.Performed functional simulation (FPGA + DDR2 +
ADC) of quite simple events to follow all the signals.
Some effort has to be put in DAQ driver to recover packed data.S
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Next StepsAnalyze a possible implementation
of fiber optic data link to be connected to the SSP
Implement Multi Board block transfer (some hints needed)
Deep debug and test (implies rewriting of some DAQ code)
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Support Slides
SBS Coll. Meeting - Front Tracker GEM 387 July 2014 - JLab
“Residual Noise” on first APV channels
Pedestal
RMS of Pedestal
Card + Flat Adapter
Condition:4 cards connected to chamber (one by flat adapter)
Cards connected to VME by 20 m long HDMI cables
Evident noise on first few (up to 8) channels of each card;
This noise is somehow masked in the card with adapter (this is way we never put great attention to it in the past)
Baseline noise at the level of 7 ADC channel.
VMEGEMHDMI cable
MP
D
Strips, physics order
SBS Coll. Meeting - Front Tracker GEM 397 July 2014 - JLab
Electronics Misconfiguration Issue
Small current drop during APV configuration; the “normal” level must restore In case of proper configuration; otherwise the electronics does not work properlyChamber appears inefficient → this likely explain the gain issue in 2013 DESY test
Electronics Low Voltage monitor
2 power lines for 2 groups of cards
BARI Gas System w/Humidity Sensor and Absorber
7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM 40