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A First Application for the Scalable Readout System: Muon Tomography with GEM Detectors RD51 Collaboration Meeting WG5 - May 25, 2010

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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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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
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
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
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
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
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
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
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
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
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
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
MT Targets

triggered

triggered

triggered

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

minimal mts with pb target
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
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

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

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
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
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
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
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
Next steps…

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

30cm 30cm 30cm prototype
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
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
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
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
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
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
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
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
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
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
Minimal MT station

Setup at GDD in April 2010

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

32

beyond fy10
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

33

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