Front GEM Chambers

Front GEM Chambers

• Design concepts– Foils– Mechanics

• Electronics and DAQ• Performance

• Current activity and plan

Evaristo Cisbani / INFN-Rome Sanità group

2012 May 25 / A1n Meeting / JLab E. Cisbani 1

People

V. Bellini coordination

E. Cisbani montecarlo, analysis, daq, test, coordination

M. Capogni digitization, montecarlo, test

S. Colilli tech

V. De Smet gas simulation, assembling procedure, test

R. Fratoni tech

F. Giuliani tech

M. Gricia tech

F. Librizzi tech

M. Lucentini tech

F. Mammoliti analysis

S. Minutoli electronics

P. Musico electronics, daq, test

F. Noto mechanics

R. Perrino gas system, test

G. Ruscica analysis

F. Santavenere tech

C. Sutera assembling, testMost of the material presented at the SBS meeting in Feb and May/2012

Chamber design Reqs and Guidelines

• Hit spatial resolution ~70 mm

• Stand large background flux (~250 MHz/cm2 g and

~1/1000 charged particles)

• Active area 120x40 cm2

• Event acquistion rate ~20 kevt/s

Minimize R&D (follow COMPASS main design)

Reconfigurability (to some extend)

Reuse solutions for SBS rear tracker


SBS Tracker GEM Chambers configuration

Chambers are made of smaller modules

Electronics along the borders and behind the frame (at 90°) – cyan and blue in drawing

Carbon fiber support frame around the chamber (cyan in drawing); dedicated to each chamber configuration

Front TrackerGeometry

x6

Back Trackers Geometry

x(4+4)

GEp(5) SBS


Foils


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Drfit, GEM and Readout foils

20 HV sectors on one side of the GEM

2012 May 25 / A

1n Meeting / JLab

E. C

isbani

5

40x50 cm2

• Large GEM module with small dead area

• Low material budget/Light Structure

• Modular design

• Flexible configuration

• Balanced weight

Improvements after first prototype• Protection resistors on the border

of the module frame (accessible)• Balance strips capacity (larger

strips are now the shortest, smaller are the longest)

• Replaced ZIF terminals (from 4 to 2 – more robust, easer to plug)

• Thanks to Kondo suggestions:– Added ring of grounding

around the readout foil (connected to the front end card GND)

– Corrected a trivial (but essential) bug in the readout layers order


Mechanics


Inner FrameGas Flow

Outer Service Frames

Inner Frame• Permaglas, 8 mm

width, 2 or 3 mm

thick

• 21 slots for

protection resistors

• 3 Gas In/ 3 Out-lets

• 10 Reference holes

• Internal spacers (3

vertical 2 horizontal)


F. Noto

Gas Flow / COMSOL MultiPhysics Simulation

V. De Smet + F. Noto

COMSOL/Thin-Film Flow ModelMaximize uniformity and steady fluxMinimize spacer apertures

Final design

2012 May 25 / A

1n Meeting / JLab

E. C

isbani

9

Flow:

60 cm3/m = 2 Vol/h

Pressure drop (Pa):

Inlet: 0.0590

Spacers: 0.0015

Module: 0.0462

Outlet: 0.0575

Total: 0.1642(underestimated)

Gas / Current solutions under testingRILSAN

pipe

GEM

10 mm

In 4 mm

Out 6 mmIn 4 mm

«Side» view

Top view →

No metallic partsCustom and commercial jointsCommercial joints are rather large (13 mm!)

Glued Permaglas

IN or OUT

SMC/KR

2012 May 25 / A1n Meeting / JLab

E. Cisbani 10

Pressure drop: 3.16 Pa/m

Out 13 mm

11

Assembling the first 40x50 cm2 module

Stretching

Gluing the nextframe with spacers

Foil Tension: T = 1 kg/cmSpacer Sector: S = 170 cm2Expected maximum pressure on foil P 10 N/m2

Maximum foil deformation:u 0.0074 * P * S / T = 12 mm

Use stretching and spacersto keep foil flat

Stretcher design from LNF / Bencivenni et al.

2012 May 25 / A

1n Meeting / JLab

E. C

isbani

12

Outer service frame 2012 May 25 / A

1n Meeting / JLab

E. C

isbani

Mechanical support of:• GEM modules• Electronics (PCBs + cables)• Additional services (gas system ...)

Carbon fiberLong bars made by 3 piecesDesign is in progressFirst prototype beginning of summer

FE cards between frame and backplanes

F. Noto

1650 mm

780

mm

13

E. C

isbani

Service Frame / Detail 2012 May 25 / A

1n Meeting / JLab

Reference pin as small mechanical support

FE Cards

Backplane

Eye bold hole

23x100 mm2

30x100 mm2

14

Material WeightGEM Chamber Weight

Module Chamber Unit WeightModule Weight

Chamber Weight

g g gFrame Honeycomb 1 3 112,09224 112,09224 336,27672Frame GEM Gap 3 9 57,4832 172,4496 517,3488Frame Drift 1 3 86,2248 86,2248 258,6744Frame Window 2 6 57,4832 114,9664 344,8992GEM foil 3 9 35,704 107,112 321,336Readout Foil 1 3 71,408 71,408 214,224Drift Foil 1 3 24,952 24,952 74,856Mylar Foil 1 3 5,68 5,68 17,04

Electronics: FE 18 54 11,92 214,56 643,68Electronics: Backplanes 4 12 150,74 602,96 1808,88Electronics: Patch Panels 0 2 150,74 0 301,48Elettronics: 3-meter HDMI-A cables 8 24 240 1920 5760FE-Backplane screws 72 216 1,5 108 324

Gas: 3 m pipes 6 18 43,3333333 260 780Gas: Patch panel 0 1 301,48 0 301,48Gas: Connectors 6 27 10 60 270

HV: cabling 2 6 100 200 600HV: Voltage Divider 1 3 150,74 150,74 452,22HV: Patch Panel 0 1 150,74 0 150,74

LV: 3m cables 8 24 100 800 2400LV: Patch Panel 0 1 150,74 0 150,74

"Fascette" 38 mm 50 200 4,5 225 900Screws 0 100 2 0 200

Total (g) 5236,15 17127,88

2012 May 25 / A

1n Meeting / JLab

E. C

isbani

15

E. C

isbani

Max deformation 2012 May 25 / A

1n Meeting / JLab

New

Material Short side (vertical)

Long side (Horizontal)

Carbon Fiber

0.004 0.081

Aluminium 0.018 0.330

Assume 20 kg of

payload

Weight applyed in the

center of the beam

Two points support

mm

16

Electronics and DAQ

2012 May 25 / A

1n Meeting / JLab

E. C

isbani

APV25 Front-End cardBackplane

MultiPurposeDigitizer (VME module)

17

Electronics Components

GEM FEC MPD DAQ

Main features:• Use analog readout APV25 chips• 2 “active” components: Front-End card and VME64x custom module • Copper cables between front-end and VME• Optional backplane (user designed) acting as signal bus, electrical

shielding, GND distributor and mechanical support

2D R

eado

ut

75 mm

49.5

mm

8 mm

Up to 10mtwisted,shielded

copper cable(HDMI)

Passive backplane(optional)

2012 May 25 / A

1n Meeting / JLab

E. C

isbani

18

E. C

isbani

Readout Electronics / FE v4

• Front-end cards: first 25 samples of revision 4 under testing

New connector: sligtly different connection scheme (middle spare pins are connected to ground)

Old connectors

2012 May 25 / A

1n Meeting / JLab

19

E. C

isbani

Readout Electronics / MPD v4

• Design of v4 under finalization

– Move to HDMI type B only

– Remove 2 Lemo connectors and

USB (more space and firmware

resources)

– Add piggy back connector for

future extension

– Trigger sampling at maximum

clock speed (240 MHz), time

resolution expected at the level of

few ns

2012 May 25 / A

1n Meeting / JLab

20

E. C

isbani

20

2012 May 25 / A

1n Meeting / JLab

(128+12)x25 ns

(2x128+7)x20 ns

+ VME64x spare readout

FEMPD transfer/processing time: ~9 ms/sample

APV long analog pipeline (>4 us): use second level trigger

Zero suppressed data

21

E. C

isbani

DAQ

Bus Interface

Generic Model(virtual class)

MPDLibrary

Low Level

I2C

Trigger

ADC

Other

High Level

Initialize

Configure

Discovery

Read

WrapperDB

Module

Structured text file for

configuration

Based on libconfig++

Main

Implemented on C++

• Run on Linux

• MPD as independent library• One configuration file (text

format)

• Use open source libconfig++

• Self consistent output binary

raw data

DAQ Software 2012 May 25 / A

1n Meeting / JLab

Analysis software:

• Based on C++/Root

• One geometry configuration file (text)

• Ingest raw data and fill a Root tree for

further analysis

Largely rewritten in the past few weeksBug fixing in progress

22

Some performance

2012 May 25 / A

1n Meeting / JLab

E. C

isbani

Desy – Mainz Test beam

23

Beam test @ DESY / Full Module Size 40x50 cm2 2012 May 25 / A

1n Meeting / JLab

E. C

isbani

One 40x50 GEM moduleOne 10x10 GEM chamberAn ustrip Si telescopeSmall scintillators for trigger

Low intensity electron beam 2-6 GeV(few KHz trigger rate)

24

Different event patternsWe extracted «good events» and measured:• Cluster charge, and x-y

correlation and ratio• Cluster size• Noise (RMS)• Selection Efficiency

2012 May 25 / A

1n Meeting / JLab

E. C

isbani

Bad event

Good event

Standard processing:

• Hot channels masking

• Common noise suppression (median)

• Pedestal subtraction

25

Cluster charge, size and noise 2012 May 25 / A

1n Meeting / JLab

E. C

isbani

Charge distribution and cluster size consistent with COMPASS data

We do not expect dramatic difference respect to COMPASS

26

Charge correlation, beam spot and SNR

Pretty good run (011)

2012 May 25 / A

1n Meeting / JLab

E. C

isbani

?

27

Noise (RMS pedestal) vs capacitance

Progress since DESY/2010:better grounding, stable firmware

2012 May 25 / A

1n Meeting / JLab

E. C

isbani

Runs differ for different GND connection

28

Latest Test under intense beam (Mainz/MAMI)12-16/09/2011

2012 May 25 / A

1n Meeting / JLab

E. C

isbani

29

Online monitor / Mainz test

Low beam current

2012 May 25 / A

1n Meeting / JLab

E. C

isbani

Event

x1

x2

x3

y2

30

Online monitor / Mainz test

High beam current

2012 May 25 / A

1n Meeting / JLab

E. C

isbani

See Vahe analysis report at SBS meeting

x1

x2

x3

y2

Event

31

Real Experiment: Olympus, Feb/2012

From Jürgen Diefenbach

The APV electronics has been installed on the Olympus 3xGEM tracker made of 6 10x10 chambers with 2D readout (pad/strip – about 2500 chs), operating in a magnetic field at the level of few kG.

Two events with opposite magnet polarity; particles bend left o right in the x-histogram

(Red triangles show hit candidates)

2012 May 25 / A

1n Meeting / JLab

E. C

isbani

32

Current activity and Plan

2012 May 25 / A

1n Meeting / JLab

E. C

isbani

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33

What we have 2012 May 25 / A

1n Meeting / JLab

E. C

isbani

Electronics:

All readout electronics ordered (order in standby); samples of the latest

(final?) FE/backplane version produced

Low Voltages and High Voltage power supplies in hands

GEM and readout foils:

About 1/3 ordered, only small part delivered

About another 1/3 funded in 2012

Mechanics:

All inner frames ordered, about ½ delivered

Outer frame prototype ordered

About 2/3 outer frames funded in 2012

Gas system:

Mostly funded and procured

Assembling:Everything ready (or under minor improvement)

34

• Electronics and DAQ:– production and test– complete firmware implementation / improve software library– optmimize readout performance– (additional user: ATLAS group working on mMeGas prototype)

• Mechanics– finalize outer service frame design and produce first prototype

• HV– Final decision on HV divider to be taken

• Gas– Near chamber configuration to be finalized

• GEM modules– assembling and test (as soon as possible)

Working on / Open activities 2012 May 25 / A

1n Meeting / JLab

E. C

isbani

35

• As soon as possible:– When the readout foils will arrive (few days ?) start assembling the first

40x50 module (about 1 module/month-> 0.5 module/week)– latest FE electronics version release for 1 module (on hand)

• July-Sept. 2012:– test the module and electronics with rad. source; if fine aks CERN form

production• July 2012:

– get outer service frame / electronics review at JLab (?)• Sep 2012:

– start mass productions of electronics• Dec 2012:

– 1st chamber completed (?)– Electronics available, ready for testing

• Dec 2013 (+2M): 4 chambers completed (?)

Plan 2012 May 25 / A

1n Meeting / JLab

E. C

isbani

Documents

Front GEM Chambers