bb / sbs front-tracker gem & electronics e. cisbani / infn-rm-sanità p. musico / infn-ge and...

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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

INFN GroupResearcher(Unit / FTE)

Tech.(Unit / FTE) Role

Bari 2 / 0.5 Gas system and beam test

Catania 3* / 1.5 3 / 2 GEM module assembling, mechanics, beam test, analysis

Genova 1** / 0.5 Electronics design and test

Rome/Sanità 1 / 0.5 3 / 2 Coordination, design, test, chamber integration, analysis, DAQ and reconstruction

Total 7 / 3.0 6 / 4

Other support: CERN / UVa / JLab


Main Technical solutions

40x50 cm2

module

Front Tracker Chamber: 40x150 cm2

Use the COMPASS approach: 3xGEM, 2D readout - one significant difference: use new

single mask GEM foil (instead of double mask) – cheaper and faster production

Modular design: chambers consists of 3 independent GEM modules (40x50 cm2) with thin

dead area

Electronics around the module, direct connection; 90 degree bending between modules

External support frame in carbon fiber (long bars) to minimize thermal deformation


Gluing

Finalization(solder resistor, check HV)

Stretching

Electronics integrationTest and characterization by rad.

source and cosmics

Permaglas FramesVisual InspectionUltrasound bath

cleaning

GEM FoilsHV curing and

quality test

Put together(align on reference pins)

Glue Curing(>24 h)

Assemblinggas lines

ElectronicsTest


Clea

n ro

om

Module production fully established in INFN-Catania

Electronics preliminary QA in Genoa

Module integration and characterization in INFN-Sanità

GEM Module construction process

Production rate2 module in 3 months

Assembling Improvements in CataniaSeveral small but effective impromevents during last 2 years; one of

the most relevent is the compression system during glue curing--- From Lead to vacuum ---


Old System based on Lead BricksCurrent System based on vacuum bagVery uniform pressure for glue degassing

Original idea from LNF- Bencivenni Group

HV divider and new GEM foils


Protective SMD

resistors

HV connector«spike» signal output

HV Divider and spike monitor circuit

Reasonably compact,

Easy to change

Include output signal for «spike» detection

Test and characterization setupAlmost finalized

Use small 10x10 GEM as «reference» (in series)

Large scintillation pads for cosmic

Test up to 3 large GEM simultaneously


SBS GEM Tracker - Test Beam / Jan 2014

ReferenceSmall GEM

3 Big GEMs DESY/EUDETPixel Telescope

Small scale final system (gas, LV, HV monitored)

Main Goals: Characterize

chambers in terms of charge sharing, efficiency and spatial resolution at different HV, gas mixture.

Figure out the gain variation of the previous test

→ Got lot's of good data with high spatial resolution information from pixel telescope

→ Stable performance (“all” conditions carefully monitored)

1-4 GeVElectronBeam


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)


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


T0+50ns(A2)


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


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


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


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


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


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


GEM Test Beam: spatial uniformity – Hit Cahrge

Reconstruction Efficiency vs #Event


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.

Several data to be analyzed

• Background level of:– 400 MHz/cm2 photons– 200 kHz/cm2 charged

• Signal width ≈ 250 ns

→ Hits/cm2/trigger ≈ 0.1

→ Ghosts/cm2/trigger ≈ 10-20 !


Three steps track reconstruction:

• Suppress accidentals and ghost

with time and charge correlation

• Associate hits with global

analysis (neural network

approach)

• Precise track reconstruction on

remaining candidate tracks by

Kalman filter method


Sij – neuron (0 or 1) – connection between two points(to be minimized)

Track Association by NN / Simulation


Energy

Neuron changing rate

Vij

Kalman Filter Reconstruction: simulation


Residues

Material Procurement Status

7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

Front Tracker Module Chamber Front Tracker In house OrderedChamber 1 6Module 1 3 18 3GEM Foils (CERN)Drift Foil 1 3 18 18GEM foils 3 9 54 51Readout 1 3 18 15Honeycomb 1 3 18 18Mechanics (RESARM)Frame 0 – Cover 1 3 18 20Frame 1 – Top 1 3 18 20Frame 2 – Drift 1 3 18 20Frame 3 – GEM 2 6 36 40Frame 4 – Readout 1 3 18 20External Frame (Plyform) 1 6 1*Electronics (EES)FE 18 54 324 250 100MPD 4 24 26Backplane 4 12 72 80Patch Panel (digital + analog) 8 48 50Electronics Cabling (LINDY)HDMI 3m cable 8 24 144 80HDMI 20m cable 5 15 90 45LV cable 4 12 72 **HV cable 7 21 126 **HV Divider 1 3 18 40LV Power Supply (6Vx20 Amp) 1 6 8HV Power Supply 1 3 18 24Gas SystemController + Flowmeters (MKS) 1 1Connectors (Legris) 10 36 212 250Patch Panel Gas 1 6 4General Patch Panel 1 2

Most of the material already in house or procured

Remaining parts will be procured in 2014

Assembling line operational

Testing line under finalization

*) Design completed, waiting first proto

**) 2014 funding

25

GEM Production and Test StatusProduced or Assembled

Tested NOT Accepted Degradation after first test

GEM foils 51 25 7

Readout+Honeycomb 15 / 18 7 1

GEM Module 5+ 3 0 2

Front End Electronics 250* 50 2 -

VME Modules 26 5+ 0 -

Backplane 80 12+

Patch Panel 50 many many returned to company***


• The very first 4 GEM foils did not pass the original quality checks, 3 recent GEM foils of

the same bunch did not pass the quality check

• One readout + honeycomb suffered bad gluing (probably still usable)

• 2 of the GEM modules passed preliminary tests but then degraded significiantly (large

dark current due to (? gas contamination ?); still chance to fix them.

• *** soldering problem, bug fixed

2009 2010 2011 2012 2013 2014 2015

Preliminary design (include MC study)

Prototyping

Procurement

Pre-Production(1st chamber)

Production

Beam Test DecDESY

SeptMainz

JuneCERN

MayDESY

JanDESY


Development phases in part affected by constraints in the flow of funding

Delivery delay of the GEM foils from CERN for prototyping and pre-production

(no significant impact in SBS, we started erlier)

During pre-production we made some fine optimization:

• GEM foil, details in construction procedure;

• one drastic change in foil quality check.

Development includes: GEM chambers, readout electronics (and related software)

Schedule and Status

Main Open Issues

1. Long cable noise

• If no fix available: change cabling topology

2. Readout plane manufacturing

• Test in high bck needed !

3. GEM modules «aging»

• To be investigated

4. Data rate / VME Crates (?)

• Implement optical fiber and SSP communication (?)


GEM Tracker Activity 2014-2015

• Continue Production

• Test, Characterization and Calibration of GEM and electronics

• Fix damaged modules/material, replace if no fix possible

• Finalization of a rubust and efficient track reconstruction

algorithm

• Complete and test the complex firmware of the DAQ

• Study (and solve) open issues


Working Space @Jlab needed

GEM chamber assembling and testing need space at JLab (layout sent in 2010)


GEM Electronic System Status

Production status of electronic boards

Firmware Update on MPD v 4.0◦VME intrerface◦Event Builder

Paolo Musico and Evaristo Cisbani

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Production StatusS

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APV Front-End cards210 delivered (some used for DESY test)140 in progress (SMD ok, to be bonded)

Backplanes74 delivered (some tested)

MPD28 delivered and tested: 2 with marginal

problems (to be fixed)Patch Panels

25 Analog Patch Panels delivered35 Digital Patch Panels delivered

MPD v 4.0 firmware updateRevised memory mappingD64 read only cycle implemented:

MBLT, 2eVME, 2eSST◦2eSST simulated peak speed: 148, 222, 296

MB/sEvent builder implemented and

simulated

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


orGEM_50x40

Series operation

~ 20 m long pipe

~ 20 m long pipe

~10 m

orGEM_50x40

Series operation

~10 m

0 20 40 60 80 100 120 140 1600

1

2

3

4

5

6

7

Plastic Tube

Inox Tube

Gas Flow (ccpm)

Hu

mid

ity

(RH

%)

< 100 ppM of H2O

bb / sbs front-tracker gem & electronics e. cisbani / infn-rm-sanità p. musico / infn-ge and...

Documents

tracker gem electronics

tracker gem6 old system

new gem foils7

quality test

electronics design

new single mask gem

spike detection test

gas system