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A First Application for the Scalable Readout System: Muon Tomography with GEM Detectors RD51 Collaboration Meeting WG5 - May 25, 2010. Marcus Hohlmann with Kondo Gnanvo, Lenny Grasso, J. Ben Locke, and Amilkar Quintero Florida Institute of Technology, Melbourne, FL, USA.

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Slide1 l.jpg

A First Application for the Scalable Readout System:Muon Tomography with GEM DetectorsRD51 Collaboration Meeting WG5 - May 25, 2010

Marcus Hohlmann

with Kondo Gnanvo, Lenny Grasso, J. Ben Locke, and Amilkar Quintero

Florida Institute of Technology, Melbourne, FL, USA


Muon tomography principle l.jpg
Muon Tomography Principle

Note: angles are exaggerated !

Incoming muons (μ±)

(from natural cosmic rays)

Q=+92e

μ

μ

Cargo container

Q=+26e

Θ

235U

92

Θ

hidden &

shielded

high-Z

nuclear

material

56Fe

26

HEU: Big

scattering angles!

μ

Θ

Regular material:

small scattering angles

Θ

Approx. Gaussian distribution

of scattering angles θ withwidth θ0:

Tracking Detector

  • Main ideas:

  • Multiple Coulomb scattering is ~ prop. to Z and could discriminate materials by Z

  • Cosmic ray muons are ubiquitous; no artificial radiation source or beam needed

  • Muons are highly penetrating; potential for sensing shielded high-Z nuclear contraband

  • Cosmic Ray Muons come in from many directions allowing for tomographic 3D imaging

μ tracks

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany


Fl tech concept mt w mpgds l.jpg
Fl. Tech Concept: MT w/ MPGDs

Use Micro Pattern Gaseous Detectors for tracking muons

μ tracks

  • ADVANTAGES:

  • small detector structure allows

  • compact, low-mass MT station

    • thin detector layers

    • small gaps between layers

    • low multiple scattering in

    • detector itself

  • high MPGD spatial resolution (~ 50 m)

  • provides good scattering angle

  • measurement with short tracks

  • high tracking efficiency

  • CHALLENGES:

  • need to develop large-area MPGDs

  • large number of electronic

    readout channels needed (→ SRS)

Cargo container

MPGD Tracking Detector (GEMs)

Small triple-GEM under assembly

hidden &

shielded

high-Z

nuclear

material

GEM

Detector

μ

Θ

Θ

MPGD, e.g. GEM Detector

~ 1.5 cm

e-

Gas

Electron

Multiplier

Detector

Readout electronics

F. Sauli

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany


General strategy l.jpg
General Strategy

  • Build first prototype of GEM-based Muon Tomography station & evaluate performance (using ten 30cm  30cm GEM det.)

    • Detectors

    • Mechanics

    • Readout Electronics → SRS !

    • HV & Gas supply

    • Data Acquisition & Analysis

  • Help develop large-area (1m  0.5m) Triple-GEMsand SRS electronics within RD51

  • Build final 1m1m1m GEM-based Muon Tomography prototype station

  • Measure performanceon shielded targets and “vertical clutter” with both prototypes

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

4


2009 10 strategy l.jpg
2009/10 Strategy

Two-pronged approach:

Build and operate minimalfirst GEM-based Muon Tomography station:

only four Triple-GEM detectors (two at top and two at bottom)

temporary GASSIPLEX electronics (~800 ch., borrowed from Saclay – THANKS !!!)

minimal coverage (read out only 5cm  5cm area in each detector)

preliminary data acquisition system (LabView; modified from MAMMA – THANKS !!!)

Objectives:

take real data as soon as possible and analyze

demonstrate that GEM detectors work as anticipated for cosmic ray muons

→ produce very first experimental proof-of-concept for GEM MT

Simultaneouslyprepare for 30cm  30cm  30cm Muon Tomography Station:

Top, bottom, and side detectors (10 detectors)

Mechanical stand with flexible geometry, e.g. variable gaps b/w detectors

Final SRS front-end electronics (15,000 ch.) with RD51

Final data acquisition with RD51 & analysis

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

5


Hardware progress l.jpg
Hardware Progress

  • Detector Assembly:

    • 7 30cm  30cm Triple-GEM detectors assembled in CERN clean rooms

    • 1 30cm  30cm Double-GEM detector assembled in CERN clean rooms (b/c one foil was lost)

    • 2 30cm  30cm Triple-GEM detectors awaiting assembly at Fl. Tech

    • 2 10cm  10cm Triple-GEM detectors assembled at Fl. Tech (for R&D purposes)

  • Basic performance parameters of triple-GEM detectors tested with X-rays and mips:

    • HV stability, sparks

    • Gas gain

    • HV plateau

    • Rate capability

    • 55Fe and mip (cosmics) pulse height spectra

  • => Six Triple-GEM detectors at CERN show good and stable performance

    One Triple-GEM detector has bad HV section; to be fixed

  • Built minimal prototype station for Muon Tomography; operated 2 weeks at CERN

    • Designed and produced adapter board for interfacing detector r/o board with Panasonic connectors to preliminary “GASSIPLEX” frontend electronics with SAMTEC connectors (Kondo Gnanvo)

    • Used 8 GASSIPLEX frontend r/o cards electronics with ~800 readout channels for two tests (Dec ’09 - Jan ’10 and April ’10, Kondo Gnanvo)

    • Developed LabView DAQ system for first prototype tests – lots of debugging work (Kondo Gnanvo)

  • Developed GEANT4 simulation for minimal MT prototype station

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

6


Triple gem detector l.jpg
Triple-GEM Detector

On X-ray bench

at GDD

terminators

Gas

outlet

768 y-strips

768 x-strips

Gas

inlet

Triple-GEM pulses

under 8 keV X-rays

Argon

escape

HV sections

Gate pulse

for ADC

High voltage board (voltage divider)

Single channel meas.

with ORTEC pre-amp

Photo peak

HV input (4kV)

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

7


Basic detector performance l.jpg
Basic Detector Performance

Results from commissioning test of Triple-GEM detectors using single-channel amp. & 8 kV Cu X-ray source at GDD

At this high voltage, the

transfer gap becomes

efficient for X-ray detection adding some pulses from the “double-GEM” structure.

(Not discharges !)

MTGEM-7

Rate plateau

Detector efficient

2104

Gas gain vs. HV

(lower threshold)

Applied Chamber HV [V]

Anode

current

vertical

strips

[nA]

Pulse height spectra

equal sharing

8 keV

X-rays

Mips

(cosmic

ray muons)

Argon

escape

peak

Charge sharing

b/w x- and y-strips

Anode current – horizontal strips [nA]

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

8


Pulse height distribution l.jpg
Pulse height distribution

Landau Fit

Minimum Ionizing Particles

(Cosmic Ray Muons)

[ADC counts]

Distribution of total strip cluster charge follows Landau distribution as expected

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

9


Minimal mt station l.jpg
Minimal MT Station

Setup of first cosmic ray muon run at CERN with four Triple-GEM detectors

Event Display: Tracking of a cosmic ray muon traversing minimal GEM MT station

Top 1

Top 2

Bottom 1

Bottom 2

3-GEM

Top 1

x

3-GEM

Top 2

Pb target

3-GEM

Bottom 1

y

3-GEM

Bottom 2

Strip Position [mm]

Preliminary

Electronics

(GASSIPLEX)

  • Pulse heights on x-strips and y-strips recorded by all 4 GEM detectors using preliminary electronics and DAQ

  • Pedestals are subtracted

  • No target present; Data taken 4/13/2010

FIT interface board

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

10


First data strip clusters l.jpg
First Data: Strip Clusters

Sharingof deposited charge among adjacent strips is important for high spatial resolution by using the center-of-gravity of charge deposition when calculating the hit position:

All recorded strip clusters

centered on highest

bin & added together

Width of Gaussian fit

to 855 measured

individual strip clusters

=> Charge is shared between up to 5 strips

=> On the average, strip cluster is 3.2 strips wide (1)

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

11


Mt targets l.jpg
MT Targets

triggered

triggered

triggered

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany


Minimal mts with pb target l.jpg
Minimal MTS with Pb target

Event recorded with Pb target present in center of minimal MTS:

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

13


Hits tracking l.jpg
Hits & Tracking

Empty Station

Real Data

Y-Z projection

X-Z projection

Station with Pb target

X-Z projection

Y-Z proj.

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany


Basic scattering reconstruction l.jpg

μ track direction

a

a

MT station

Scattering

Object

Scattering

angle

b

b

Basic Scattering Reconstruction

  • Simple 3D reconstruction algorithm using Point of Closest Approach (POCA) of incoming and exiting 3-D tracks

  • Treat as single scatter

  • Scattering angle:

    (with >0 by definition)

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany


Muon tomography with gems l.jpg

Mean scattering angles  in x  y  z = 2mm  2mm  20mm voxels (x-y slices taken at z = 0mm)

Muon Tomography with GEMs !

First-ever experimental GEM-MT Data

empty

Fe

Muons reconstructed:

Empty 558

Fe 809

Pb 1091

Ta 1617

Nominal target position

It works !!!

Pb

Ta

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

16


Mt front view x z l.jpg
MT Front View (x-z)

Fe

Pb

Ta

Empty

<> [deg]

<> [deg]

<> [deg]

<> [deg]

Imaging in the vertical not as good as imaging in x-y because triggered muons are close to vertical

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany


3d target imaging l.jpg
3D Target Imaging

Fe

Pb

Ta

Empty

 [deg]

Scattering points (POCA) colored according to measured scattering angle

(Points with  < 1o are suppressed for clarity)

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany


Comparison data vs mc l.jpg
Comparison Data vs. MC

Mean scattering angles  in x  y  z = 2mm  2mm  20mm voxels (x-y slices taken at z = 0mm)

Data

Monte Carlo (~ 20 times data)

empty

empty

Fe

Fe

Nominal target position

Pb

Ta

Ta

Pb

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

19


Comparison data vs mc cont d l.jpg
Comparison Data vs. MC cont’d

  • Only data for which the POCA is

  • reconstructed within the MTS volume are used for comparison.

  • For measurements at small angles ( < 1o), MC and data do not agree that well, yet.

  • This is presumably due to:

    • the fact that the GEM detectors in the MTS have not yet been aligned with tracks. For now, we are solely relying on mechanical alignment.

    • Any misalignment increases the angle measurement because the scattering angle is by definition positive.

    • the fact that the GEANT4 description of the materials used in the station itself is not yet perfect

Fe

Empty

Ta

Pb

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany


Slide21 l.jpg

Next steps…

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany


30cm 30cm 30cm prototype l.jpg
30cm30cm30cm Prototype

Planned Geometry & Mechanical Design:

?

31.1cm

31.7cm

“Cubic-foot” prototype

?

Maximizes geometric acceptance

GEM support

(with cut-out)

Front-end cards

GEM detector

active area

Target plate

HV board

All designs by Lenny Grasso; under construction at Fl. Tech

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

22


30cm 30cm 30cm prototype23 l.jpg
30cm30cm30cm Prototype

APV25 readout chip

  • originally developed for

  • CMS Si-strip detector by ICL

  • production in 2003/04

  • yield of 120,000 good chip dies

  • 128 channels/chip

  • preamplifier/shaper with

  • 50ns peaking time

  • 192-slot buffer memory

  • for each channel

  • multiplexed analog output

  • integrated test pulse system

  • runs at 40 MHz

  • used e.g. by CMS, COMPASS,

  • ZEUS, STAR, Belle experiments

  • MOST IMPORTANT:

  • Chip is still available

  • “Cheap” ! (CHF28/chip)

  • We have procured 160 chips

  • for our ten 30cm × 30cm detectors

  • (min. 120 needed)

HEP group, Imperial College, London

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

23


Front end hybrid card l.jpg
Front-end hybrid card

  • 128 channels/hybrid

  • Integrated diode protection

  • against sparks in GEM detector

  • Estimated cost: EUR55/card

  • Plan to get 160 cards for MT

  • 8 Prototype boards made at CERN

  • First on-detector tests performed

  • with MT-GEMs at CERN by Sorin,

  • Hans, Kondo (→ Sorin’s next talk):

Connector

to chamber

Diode

protection

for chip

APV

25

HM

HM

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

24


30cm 30cm 30cm prototype25 l.jpg
30cm30cm30cm Prototype

Electronics & DAQ under development

Est. cost per electronics channel: $1-2

Prototypes of basically all

components exist by now

and are under test at CERN

by RD51 electronics group

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

25


Plans for 2 nd half of 2010 l.jpg
Plans for 2nd half of 2010

  • Analyze data for minimal station

    • Measure performance: resolution, efficiency, muon tomography

    • Test other reconstruction methods (EM, Clustering) besides POCA on real data

    • Publish results

  • Build & operate 30cm  30cm  30cm MT prototype with SRS

    • Help develop DAQ for SRS (→ software!)

    • Commission all GEM detectors with final SRS electronics & DAQ at CERN

    • Develop offline reconstruction

    • Get experimental performance results on muon tracking

    • Take and analyze lots of Muon Tomography data at CERN

    • Test performance with shielded targets in various configurations

    • Ship prototype to Florida and install in our lab; continue MT tests there

  • Development of final 1m  1m 1m MT station

    • Prepare for using large-area GEM foils (~100cm  50cm):

      Adapt thermal stretching technique to large foils

    • Try to simplify construction technique:

      Build small Triple-GEM detectors without stretching GEM foils

      (using our standard CERN 10cm  10cm detectors, going on now)

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany


Towards 1m 1m 1m mt station l.jpg
Towards 1m  1m 1m MT station

New infrastructure for stretching GEM foils:

  • Thermal stretching method (plexiglas frame)

  • Heating with infrared lamps (40-80oC)

  • On flat metallic optical bench ( = heat bath)

  • Everything inside large mobile clean room

  • Potentially scalable to 1-2 m for large GEMs

New grad students: Mike & Bryant

2m optical bench

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany


Funding situation l.jpg
Funding situation

  • Good news:

    • Substantial progress with hardware in 2009/10 and strong support from RD51 have convinced Dept. of Homeland Security to continue project for one more year

    • Funding action for June ’10 – May ’11 in progress

    • Funds for full SRS readout system (15k ch.) for “cubic-foot” station expected to be available in ‘10

    • Continuing to fund post-doc (Kondo) and one grad student (Mike) to work on project

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany


Acknowledgments l.jpg
Acknowledgments

A big to RD51:

  • Rui, Miranda for support w/ building the detectors

  • Esther, Fabien, Maxim, (Saclay) for lending us the GASSIPLEX cards – twice…

  • Theodoros (Demokritos) & MAMMA for getting us started on the LabView DAQ system

  • Leszek, Serge, Marco & Matteo (GDD) for all the help with setting up various tests in the GDD lab

  • Hans & Sorin for all the design, development, and testing work on the SRS

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany


Slide30 l.jpg

Backup Slides

M. Hohlmann, Fl. Inst. of Technology - DNDO review #7, Washington, D.C.

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

4/16/2010

30


Triple gem design l.jpg
Triple-GEM design

}

Top honeycomb plate

Follows original

development for

COMPASS exp.

& further develop-

ment for TERA

}

Drift cathode and spacer

}

}

3 GEM foils

stretched & glued

onto frames/spacers

}

2D Readout Foil

with ~1,500 strips

}

}

Bottom honeycomb base plate

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany


Minimal mt station32 l.jpg
Minimal MT station

Setup at GDD in April 2010

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

32


Beyond fy10 l.jpg
Beyond FY10…

Muon Tomography

with

integrated -detection ?

Large photosensitive GEM Detector (100-200 keV ’s) ?

Fl. Tech – U. Texas, Arlington planned joint effort (Physics & Material Science Departments)

M. Hohlmann, Fl. Inst. of Technology - DNDO review #7, Washington, D.C.

M. Hohlmann, Florida Institute of Technology - RD51 Coll. Meeting, Freiburg, Germany

4/16/2010

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