Marcus Hohlmann High Energy Physics Group, P/SS Dept.

1. Detecting nuclear contraband with cosmic ray muonsor“How to thwart nuclear terroristswith subatomic particles” Marcus Hohlmann High Energy Physics Group, P/SS Dept. P/SS Freshman Seminar, Sep 19, 2012

2. Nightmare 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 M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

3. Sci. Am., 4/2008 Challenge in Detecting Nuclear Contraband ~ 800 Radiation Portal Monitors (n,) in U.S. • In 2002, reporters managed to smuggle a cylinder of depleted uraniumshielded 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! Sci. Am.,4/2008 6.8 kg DU • IAEA: During 1993-2006, 275 confirmed incidents with • nuclear material and criminal intent; 14 with HEU, 4 with Pu. HEU can be hidden from conventional radiation monitoring because emanating radiation (,) is easy to shield in regular cargo (few mm Pb) Scientific American, April 2008 ! M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

4. A Potential Solution: Muon Tomography - Concept Muons are subatomic particles that come from cosmic rays and pass through us all the time. μ μ Detectors locate muons, giving us an incoming vector. μ- Uranium Large Scattering μ- Fe U Muons are scattered more by higher-Z materials, e.g. uranium. Large Scattering Small Scattering Iron Small Scattering Muons are scattered less by lower-Z materials, e.g. iron. Detectors locate muons, giving us an outgoing vector. The location and angle of scattering are reconstructed using the incoming and outgoing vectors.

5. WIRED magazine article Article on first Florida Tech MT results WIRED online magazine, front-page, July 1, 2010 M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

6. What’s a muon () ? • 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 Elementary Particles in the Standard Model of Particle Physics me = 0.511 MeV/c2 m = 105.658 MeV/c2 M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

7. Cosmic Ray Air Showers Credit: CROP, Creighton U. M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

8. Useful 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. M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

9. Why use cosmic ray muons ? CR Muons don’t lose much energy due to ionization when passing through matter: Stopping power Muons produced by cosmic rays M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

10. How a GEM detector works ± Detector volume filled with Ar/CO2 70:30 gas mixture e- Ar+ CO2+ Micro-pattern gas detector (MPGD) - 300 – 500 V (on each of 3 GEMs) 1cm + 128 el. channels (400 m pitch) Florida Tech triple-GEM Anode strips ~ 30 cm detects an electronic pulse M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

11. Electron Multiplication • 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 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. • Objective: Understanding • the gain in standard GEM • ANSYS: model & mesh the GEM • Magboltz 8.9.6: relevant cross • sections of electron-gas interactions • Garfield++: simulate e- avalanches • Single electron-ion pair created • Ar/CO2 70:30 • Edrift = 1 kV/cm (above GEM) • Einduc = 3 kV/cm (below GEM) • VGEM = 400 V (across GEM) Courtesy: Sven Dildick, Heinrich Schindler, Rob Veenhof M. Titov (Saclay), CERN Detector Seminar, 4/12 Developed within the framework of the RD51 WG4 Software Activities http://garfieldpp.web.cern.ch/garfieldpp/examples/gemgain M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

12. Full 30cm30cm30cm Prototype Geometry & Mechanical Design (Student Project): ? 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; constructed at Fl. Tech M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

13. Muon Tomography Station upstairs HEP-A Lab (tour after talk) Targets 8 GEM Detectors 12,288 readout channels M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

14. Custom Electronics Development 30cm × 30cm (1536 strips) HDMI connector 12,288 readout channels (for 8 GEM Detectors) APV25 Hybrid (128 ch.) Diode protection ADC in coll. with CERN Panasonic connector Bonded APV25 chip Slave card connector M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

15. Typical 2D Muon “Hit” in GEM det. pulse height (ADC counts) X-Strip Cluster X-Strip Number pulse height (ADC counts) gives position measurement in x and y with 100-200 µm precision Y-Strip Cluster Strip Y-Strip Number M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

16. 10 Muon Tracks in Empty Tomography Station Real Data This event display  UG project M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

17. 1000 Muon Tracks in Empty Tomography Station Real Data This event display  UG project M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

18. Simple reconstruction algorithm using Point of Closest Approach (“POCA”) of incoming and exiting 3-D tracks Treat as single scatter Scattering angle: Scattering Reconstruction M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

19. MT Image Reconstruction Top View W Pb U Fe Sn Point-of-closest-approach reconstruction for incoming & exiting track (performed by UG and grad students) M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

20. MT Image Reconstruction Fe Sn W Pb U Side views Point-of-closest-approach reconstruction for incoming & exiting track W Pb U Fe Sn M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

21. Uranium Shielded w/ Bronze 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 . DU 1.7cm • Mixed track selection • 187,731 reconstructed tracks • NNP cut = 10 • 2 mm x 2 mm x 40 mm voxels M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

22. With Lead Shielding Lead box with 3.4mm thick walls Tantalum inside Lead Tungsten Tin Uranium Iron M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

23. Muon Tomogram 40 mm XY slices descending in Z by 5 mm per frame The shielded targets are clearly visible in the reconstruction Tantalum Lead Tungsten Tin Uranium Iron • Combinatoric track selection • 292,555 reconstructed tracks • NNP cut = 5 • 2 mm x 2 mm x 40 mm voxels M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

24. Past 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 M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

25. Northrop-Grumman Science Champions Ben Locke receiving award from NG officials (April 2011) Also got to present his research to members of Congress (“Posters on the Hill”) M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

26. Current 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 * • AnkitMohapatra, 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 M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

27. 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: hohlmann@fit.edu M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

28. m See us at… http://research.fit.edu/hep_labA/ θFIT Thank you ! M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

29. Tour 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 M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

30. BACKUP MATERIAL M. Hohlmann - Detecting nuclear contraband with cosmic ray muons

31. Simulation: “FIT” Scenario “FIT” is made of 2 cm thick uranium blocks M. Hohlmann - Detecting nuclear contraband with cosmic ray muons