detecting nuclear contraband with cosmic ray muons or “how to thwart nuclear terrorists with...

Detecting nuclear contraband Detecting nuclear contraband with cosmic ray muonswith cosmic ray muons

oror“How to thwart nuclear terrorists“How to thwart nuclear terrorists

with subatomic particles”with subatomic particles”

Marcus Hohlmann

High Energy Physics Group, P/SS Dept.

P/SS Freshman Seminar, Sep 19, 2012

Sep 19, 2012 M. Hohlmann - Detecting nuclear contraband with cosmic ray muons 2

Nightmare ScenariosNightmare Scenarios• Terrorist smuggle highly

enriched uranium (HEU) or plutonium across borders and destroy a city by detonating a nuclear bomb, or

• Terrorists smuggle highly radioactive material into a city and disperse it with a conventional explosion (“dirty bomb”) making portions of the city uninhabitable.

T.B. Cochran and M.G. McKinzie, Scientific American, April 2008


Challenge in Detecting Nuclear ContrabandChallenge in Detecting Nuclear Contraband

HEU can be hidden from conventional radiation monitoring because emanating radiation (,) is easy to shield in regular cargo (few mm Pb)

~ 800 Radiation Portal Monitors (n,) in U.S.

Scientific American, April 2008Sci. Am., 4/2008

• In 2002, reporters managed to smuggle a cylinder of depleted uranium shielded in lead in a suitcase from Vienna to Istanbul via train and in a cargo container through radiation monitors into NY harbor. Cargo was flagged for extra screening, but DU was not sensed.• In 2003, used route Jakarta – LA, same result!

6.8 kg DU

• IAEA: During 1993-2006, 275 confirmed incidents with nuclear material and criminal intent; 14 with HEU, 4 with Pu.

Sci. Am.,4/2008

!

Fe U

A Potential Solution: Muon Tomography - ConceptMuons are subatomic particles that come from cosmic rays and pass through us all the time.

Detectors locate muons, giving us an incoming vector.

Detectors locate muons, giving us an outgoing vector.

Muons are scattered more by higher-Z materials, e.g. uranium.

The location and angle of scattering are reconstructed using the incoming and outgoing vectors.

Muons are scattered less by lower-Z materials, e.g. iron.

μ

Uranium

μμ-

μ-

Iron

LargeScattering

Small Scattering

LargeScattering

Small Scattering

4

WIRED magazine articleWIRED magazine article


WIRED online magazine, front-page, July 1, 2010

Article on fir

st

Florida Tech

MT resu

lts


• Elementary particle (point particle)

• Carries one ele-mentary charge ±e: + and -

• Very similar to an electron, but ~200 times more massive

• Unstable ( = 2.2 s):

• Gets continuously produced in cosmic ray air showers

What’s a muon (What’s a muon () ?) ?Elementary Particles in the Standard Model of Particle Physics

me = 0.511 MeV/c2

m = 105.658 MeV/c2

Cosmic Ray Air ShowersCosmic Ray Air Showers


Credit: CROP, Creighton U.


Useful Muon PropertiesUseful Muon Properties• Muons produced in the atmosphere by cosmic rays

can easily pass through 8 ft. of solid steel before being absorbed. Hard to shield against!

• In fact, they are coming through the ceiling and all the floors and the concrete roof above it and are entering into our classroom (and you) RIGHT NOW!

• Even though muons do not get absorbed easily, they DO scatter in the strong electric field of the nuclei that make up all objects.

• The additional radiation exposure during scans, e.g. passenger vehicles with people inside, is zero because muons are natural background radiation.


Why use cosmic ray muons ?Why use cosmic ray muons ?CR Muons don’t lose much energy due to ionization when passing through matter:

Muons producedby cosmic rays

Stoppingpower


How a GEM detector worksHow a GEM detector works

1cm

detects an electronic pulse

e-

Detector volume filled with Ar/CO2 70:30 gas mixture

Ar+

CO2+

±

Micro-pattern gas detector (MPGD)

Anode strips

+- 300 – 500 V (on each of 3 GEMs)

Florida Tech triple-GEM

128 el. channels (400 m pitch)

~ 30 cm

Objective: Understandingthe gain in standard GEM

• ANSYS: model & mesh the GEM• Magboltz 8.9.6: relevant cross sections of electron-gas interactions• Garfield++: simulate e- avalanches

• Animation of the avalanche process (electrons are blue, ions are red, the GEM is orange)• Simulation → keep track of electron and ion drifting and ion losses at the upper GEM electrode

Courtesy:Courtesy: Sven Dildick, Sven Dildick, Heinrich Schindler,Heinrich Schindler,

Rob VeenhofRob Veenhof

Developed within the framework of the RD51 WG4 Software Activities

http://garfieldpp.web.cern.ch/garfieldpp/examples/gemgain

Electron Multiplication Electron Multiplication M

. Tito

v (S

acla

y), C

ER

N D

etec

tor S

emin

ar, 4

/12

• Edrift = 1 kV/cm (above GEM)• Einduc = 3 kV/cm (below GEM)• VGEM = 400 V (across GEM)

A voltage of 400V is applied between the two GEM electrodes. The primary electrons created by the ionizing particle drift towards the GEM holes where the high electric field triggers the electron multiplication process.

• Single electron-ion pair created• Ar/CO2 70:30

Sep 19, 2012 11M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

http://garfieldpp.web.cern.ch/garfieldpp/examples/gemgain


Full 30cm30cm30cm Prototype

31.1cm

31.7cm

All designs by Lenny Grasso; constructed at Fl. Tech

Target plate

GEM su

pport

(with

cut-o

ut)Front-end ca

rds

GEM detector

active area

HV board

Maximizes geometric acceptance

?

? Geometry & Mechanical Design (Student Project):

“Cubic-foot” prototype

Muon Tomography Station upstairs


12,288readoutchannels

HEP-A Lab(tour after talk)

8 GEM Detectors

Targets

Custom Electronics DevelopmentCustom Electronics Development


Diode

protection

HDMI

connector

APV25 Hybrid (128 ch.)

Panasonic

connector

Slave card

connector

Bonded

APV25

chip

30cm × 30cm

(1536 strips)

12,288 readout channels

(for 8 GEM Detectors)

ADC

in coll.with

CERN

Typical 2D Muon “Hit” in GEM det.Typical 2D Muon “Hit” in GEM det.


X-Strip Number

Y-Strip Number

X-Strip Cluster

Y-Strip Cluster

pulseheight(ADC counts)

pulseheight(ADC counts)

Strip

gives position measurement in x and y with 100-200 µm precision

10 Muon Tracks in Empty Tomography Station10 Muon Tracks in Empty Tomography Station

Sep 19, 2012 M. Hohlmann - Detecting nuclear contraband with cosmic ray muons 16This event display UG project Real Data

1000 Muon Tracks in Empty Tomography Station1000 Muon Tracks in Empty Tomography Station

Sep 19, 2012 M. Hohlmann - Detecting nuclear contraband with cosmic ray muons 17This event display UG project Real Data


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

• Treat as single scatter• Scattering angle:

Scattering ReconstructionScattering Reconstruction

a

b

U

WPb

FeSn

MT Image Reconstruction MT Image Reconstruction Top View

Point-of-closest-approach reconstruction for incoming & exiting track

(performed by UG and grad students)Sep 19, 2012 19M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

MT Image Reconstruction MT Image Reconstruction

Side views Point-of-closest-approach reconstruction for incoming & exiting track

Sep 19, 2012 20M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

U

WPb

FeSn

Sn Fe U Pb W

Uranium Shielded w/ BronzeUranium Shielded w/ Bronze

• Mixed track selection• 187,731 reconstructed tracks• NNP cut = 10• 2 mm x 2 mm x 40 mm voxels

40 mm XY slices descending in Z by 5 mm per frame


Tin-bronze shielding (83% Cu, 7% Sn, 7% Pb, 3% Zn) with X0 = 1.29 cm & 1.7 cm walls

.

1.7cm

DU

With Lead ShieldingWith Lead Shielding

LeadTantalum

Tungsten

UraniumTin Iron


Lead box with 3.4mm thick walls

inside

Muon TomogramMuon Tomogram

The shielded targets are clearly visible in the reconstruction

LeadTantalum

Tungsten

UraniumTin Iron

• Combinatoric track selection• 292,555 reconstructed tracks• NNP cut = 5• 2 mm x 2 mm x 40 mm voxels


40 mm XY slices descending in Z by 5 mm per frame


Past UG Research StudentsPast UG Research Students• Georgia Karagiorgi, Ph.D. (HEP), MIT, 2010; now Research

Scientist, Nevis Labs, Columbia U. *• Julian Spring, Ph.D. cand. (HEP), Boston U.• Nick Leioatts, Ph.D. cand. (Biophysics), Rochester U. *• Jen Helsby, Ph.D. cand. (Astrophysics), U. Chicago• Patrick Ford, Ph.D. stud. (EE), Texas Tech• Mike Abercrombie, Ph.D. stud. (physics), Wash. U., St. Louis • Xenia Fave, Ph.D. stud. (medical physics), U. Texas• Richie Hoch, software engineer, General Dynamics Corp. • Ben Locke, software engineer, Harris Corp. *• Will Bittner, software engineer, IBM Linux Research Center• Jeremy Janney, Navy officer (nuclear submarines)

and many others… * started during freshman year

Northrop-Grumman Science ChampionsNorthrop-Grumman Science Champions


Ben Locke receiving awardfrom NG officials

(April 2011)

Also got to present hisresearch to

members of Congress(“Posters on the Hill”)


Current UG Research StudentsCurrent UG Research Students• Kim Day, Grid Monitoring & Muon Tomography Analysis *• Liz Esposito, GEM Detector Testing • Johanna-Laina Fischer, Cluster Computing & Grid, Web *• Eric Hansen, Muon Tomography Hardware *• Michael Kane, Cluster Computing & Grid *• Swapnil Kumar, MT Upgrade Mechanics• Erik Maki, 3D Visualization of Muon Tomography Data *• Ankit Mohapatra, Gaseous Detector Simulations• Mike Phipps, Muon Tomography Analysis • Jessie Twigger, GEM Detector Construction & Test *• Kimberly Walton, Altium printed circuit board Design for GEM Readout• Jake Wortman, Muon Tomography Hardware *• Christian Zelenka, Muon Tomography Analysis & Operations

* started during freshman year


Interested ?Interested ?• My group is always hiring good UG

students – even freshmen!• Come “ask and you shall research”:

– Talk to me after this presentation or any time during my office hours

• TR4-5, W11-12, in Rm. 343 (go through my lab 341)– Send email: [email protected]

mailto:[email protected]

See us at…http://research.fit.edu/hep_labA/

θFIT


Thank you !

Tour of my labTour of my lab

• For those interested, I will guide a brief tour of my research lab NOW !• Feel free to talk to the research students

in the lab afterwards


BACKUP MATERIALBACKUP MATERIAL


Simulation: “FIT” ScenarioSimulation: “FIT” Scenario


“FIT” is made of

2 cm thick uranium blocks

detecting nuclear contraband with cosmic ray muons or “how to thwart nuclear terrorists with...

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