Accelerators in Homeland Security William Bertozzi Wilbur Franklin

Accelerators in Homeland Security William Bertozzi Wilbur Franklin, Alexei Klimenko, Steve Korbly Robert Ledoux, Rustam Niyazov, Dave Swenson Consultants: Fred Mills, Martin Berz, Kyoko Makino

Introduction - Outline n What are the events that Homeland Security is trying to prevent? n What are the Dangers we want to discover? n What processes are used to discover these dangers? n Radiography (photon and neutron) n Neutron induced reactions n Photon induced reactions n The role that accelerators play n Neutron generation n Reactions used n Intensities required n Photon generation n Hadron induced reactions n Bremsstrahlung n Monochromatic photon sources n Important characteristics of electron accelerators n Novel approaches to accelerators

Some Important Dangers n Explosives n Examples of extensive damage n Oklahoma, Lebanon, Lockerbie, Halifax (1917) n Important elements: N, O, Cl, Na, S, K, P (and fulminates) n Toxic Substances n Mustard gas (C 4 H 8 Cl 2 S), Sarin (C 4 H 10 FO 2 P), Phosgene (CCl 2 O), etc. n Dirty Bombs n 137 Cs, 60 Co, etc. n Shielding materials: Pb, W, Fe, etc. n Special Nuclear materials n 235 U, 239 Pu, 237 Np n Weapons of Mass Destruction n 235 U, 239 Pu, 237 Np, Explosives, Tamper materials, etc.

Detection: Possible Nuclear Pathways Beam Measured Particle Neutrons: Scattering, Fission (Neutrons) Photons: Capture, Scattering Photons: Nuclear Resonance Fluorescence Effective Z (EZ-3 DTM) Neutrons: Fission (Prompt Neutrons)

The Roles that Neutrons Play n Transmission radiography n Capture reactions leading to specific decays n Example: Many, but not ubiquitous if speed is needed, (even-even small cross sections) n Inelastic scattering leading to specific decays n Example: Many, but energetic neutrons produce backgrounds. n Induced fission n Thermal capture and fast capture n Others

Neutron Generators n Accelerator-based fusion: n D-D: ~2. 5 Me. V 2 H + 2 H → 3 He + n n D-T: ~14. 1 Me. V 3 H + 2 H → 4 He + n n Adelphi Technology n DD 109 n/s n DD 1010 n/s n DT 1014 n/s n DU amplifier n 60 k. W n Stripping reactions – example: 9 Be(D, n)10 B; Controllable energy, Van de Graaff, RFQ, Cyclotrons

Detection Processes that Use Photons n Transmission Radiography n Density dependence of penetration n Nuclear Resonance Fluorescence n Scattering from nuclear states n Transmission absorption n Effective –Z determination n Multiple processes yielding strong Z-dependence n Photon Induced Fission n Distinctive properties of Prompt neutron energy spectra

NRF and EZ-3 D with 3 D Voxels, 2 -D NRF Transmission Detection and Prompt Photofission Neutrons

Radiography with Photons Pictures courtesy Australian Customs and Border Protection Service

Nuclear Resonance Fluorescence

Analogy: NRF to Optical Spectrometry Optical Spectroscopy NRFI Spectroscopy “Bremsstrahlung” Spectrum 3 -D Imaging of Back-angle High-Energy Photons 2 -D Isotope Specific Transmission Imaging

Nuclear Resonance Fluorescence Physics Doppler broadened width: ~ 12 e. V (N), ~ 3 e. V (U) ~~ Incident Photons Resonant Photon Nitrogen (14 N) 7. 029 Me. V Oxygen (16 O) 7. 117 Me. V Natural width: ~ 100 me. V Carbon (12 C) E Carbon (13 C) 6. 917 Me. V Recoil Shift 5. 691 Me. V 4. 915 Me. V 4. 439 Me. V 3. 685 Me. V 3. 089 Me. V 2. 313 Me. V NRF Emitted Photons n Energy Range 1 -8 Me. V n Nearly Isotropic n Downshifted (Doppler recoil) ~ 1 ke. V n No self absorption

Alcohol NRF Spectrum

NRF Spectrum from 235 U Ebeam = 2. 1 Me. V Measurements performed with PNNL

Effective – Z Determination

NRF Spectrum from 239 Pu Ebeam = 2. 8 Me. V Measurements performed with LLNL

EZ-3 D™ Technology Summary Compton Pair Production Coulomb Scattering Beam e. Photon Back-Angle Photon Z n EZ-3 D™ effect ~ n Detection is automated n Rapidly identifies high-Z anomalies Single Compton Scatter with Ebeam = 5 Me. V • Ephoton (120 o) = 320 ke. V • Ephoton (180 o) = 240 ke. V Pair Production → e+e- annihilation (~Z 2) • Ephoton = 511 ke. V

Tests @ UCSB Low Z Materials Beam §Truck engine with various Pb Sn materials embedded. §Pb §Sn §C 4 Engine C 4 §Density reconstruction §Two points of high density material: Pb, Sn §One point with low Z eff §Effective Z identification § Two points with high Z §One point with low Z eff 18 eff: Pb, Sn

Prompt Neutrons from Photon Induced Fission

Prompt Neutrons from Photon Induced Fission n C. P. Sargent, W. Bertozzi, P. T. Demos, J. L. Matthews, and W. Turchinetz, Prompt Neutrons from Thorium Photofission, Phys. Rev. 137, B 89 - B 101 (1965) n Time-of- Flight Measurement of Neutron Energy Spectra and Angular Distribution n Less than 7% of prompt neutrons come from scission at separation n Prompt neutrons from photon induced fission result from fully accelerated fragments (velocity boost) n Energy distribution of prompt neutrons extends past 8 Me. V n Energy distribution independent of photon energy below 10 Me. V

Prompt Photofission Neutrons n n n Prompt, high energy neutrons provide unique signal for fissile material Neutron energy distribution independent of incident photon energy Minimal background contamination above threshold Significant neutron yield for E > 3 Me. V → highly transmissive Relative to Prompt n Delayed Photons ~1/10 n Delayed Neutrons ~1/200 Ebeam = 9 Me. V Photon events Neutron events 3 Mev 6 Mev Lead HEU

Important Properties of Photon Beams n Energy n n Radiography: ≤ 9 Me. V NRF: 1. 5 – 7. 1 Me. V; energy of states Effective – Z : E ~ 9 Me. V (but lower energy is effective) Photon induced fission: 5. 3 Me. V < E < ~9 Me. V n Intensity: Depends on cargo attenuation, speed of detection, and counting system n n Radiography: presently use linear accelerators at < 100 μA NRF: ~ 108 γ/s/e. V Effective – Z: Intensities similar to NRF Photon Induced fission: As much as possible for dense cargoes, but very effective at intensities similar to NRF n Duty Cycle n Radiography: Linacs at 10 -3 duty; ion integration; (photon counting) n All other techniques count individual events with spectral information n High duty cycle is a premium for event counting at high intensities

Electron Accelerators For Inspection n Electron accelerators are important tools for inspection applications n Important criteria for accelerators n Energy: ~ 3, 6, 9 Me. V n Intensity: several m. A n Duty cycle: As large as possible n Continuous time distribution (high duty cycle) desirable n Discrete event counting enhanced n Improves detector performance n Improves Signal to Noise, S/N n Existing technology for these applications is limited n Duty cycle limited in prevailing technology (RF linacs) n Large spatial profile for electrostatic machines n High initial and operating costs for commercial high duty cycle machines (e. g. IBA Rhodotron) n Need for new technology providing high duty cycle beams at low cost, small spatial profile and portable design for widespread adoption

Passport Compact Accelerator Objectives n Passport Systems has received SBIR funding to demonstrate a new type of compact, cost efficient electron accelerator n Phase II - Design, build and demonstrate an operational prototype n n High duty cycle, variable intensity Accelerate electrons to energies for scanning applications Significantly lower cost, spatial requirements vs. existing technology Prototype product for demonstration to customers

The FFAG Induction Accelerator n Simple concept of induction with static guide magnetic fields n Simple power supply consideration n Simple pulsed mode n No radiofrequency power n Induction Core requirements n High permeability n High saturation field n Low losses n High duty ratio possible: to 50% (Kerst) n Dynamic beam current modalities easily achieved

Types of FFAG Electron Accelerators n Scaling Accelerators n Radial sector n Inventors: Kieth Symon, Andre Kolominsky, Andre Lebedev, Tihiro Ohkaiwa n Spiral sector n Inventor: Donald W. Kerst n Non Scaling n Linear field with edge modifications n Inventor: C. Johnstone n Others to be invented

Theoretical Model n Spiral ridge model “Flutter”

A Spiral Sector FFAG (~ 125 ke. V) Inventor: Donald W. Kerst “Innovation Was Not Enough”: Jones, Mills, Sessler, Symon and Young; World Scientific, Singapore, To be published

Theoretical Model n Radial sector model “Flutter”

A Radial Sector FFAG (~ 425 ke. V) Inventors: Kieth Symon, Andre Kolominsky, Andre Lebedev, Tihiro Ohkaiwa “Innovation Was Not Enough”: Jones, Mills, Sessler, Symon and Young; World Scientific, Singapore, To be published

50 Me. V Radial Sector Electron Accelerator Two-Way Model at the Stoughton site, 1961 MURA “Innovation Was Not Enough”: Jones, Mills, Sessler, Symon and Young; World Scientific, Singapore, To be published

CAP Acceleration Mechanism - Simplified Top View V time Induction Core ~10 -4 s I T time Side View Accelerating Gap Imparts V = ΔE On Each Turn t Time for full acceleration di/dt = V / L DC = [(T - t)/T] x 0. 5 For symmetric square pulse V = E·dl

Tools Used in Design n Opera from Vector fields n FFAG Guide fields and relation to magnetic geometry n Electron gun and injection optics integrated to FFAG guide orbits n Omnitrak n Electron gun and injector optics n n Cathode parameters Thermal effects Electrode parameters Emittance n Cosy n n n Tracking orbits through fields Establishing dynamic apertures Extension for tracking each orbit with energy gain during each orbit Establishing injection parameters to miss gun on first few turns Establishing likely resonances Establishing tunes

Tracking Examples n Mechanical Models n Opera derived Magnetic Fields n COSY tracking n n n Dynamic apertures Tunes Orbit by orbit tracking Transmission through mechanical model Establish resonance examples n Two emittance examples at injection n Injection example n Tunes and resonances

Acceptances Horizontal acceptance Vertical acceptance 50 ke. V 150 500 6000 1500 3000 4000 5000 7300 8500 9000 ke. V

Particle Tracking 1. 0 x 1. 0 mm-mrad Horizontal Vertical 50 ke. V 150 500 6000 1500 3000 4000 5000 7300 8500 9000 8000 7500 ke. V

Emittance in X and Y 1. 0 x 1. 0 mm-mrad Company Proprietary

Transmittance 1. 0 x 1. 0 mm-mrad

Particle Tracking 0. 5 x 2 mm-mrad Horizontal Vertical 50 ke. V 150 500 7300 7500 8000 8500 9000 ke. V

Emittance in X and Y 0. 5 x 2. 0 mm-mrad

Transmittance 0. 5 x 2. 0 mm-mrad

Tune Calculations

Horizontal Tunes and Amplitude Dependant Tune Shift

Vertical Tunes and Amplitude Dependant Tune Shift

COSY Particle Tracking in Phase Space 0 injection Orbit 2 Orbit 1 Orbit 3 inflector

Understanding One 50 ke. V Acceptance Vertical acceptance Amplitude dependant tune shift � y=8 p mm mr 4 X fold symmetry 1. 80=9/5 1. 75=7/4 � y=17 p mm mr 5 X fold symmetry

Conclusions n Importance of High Duty Cycle n Feasibility of Induction Accelerator Modality n n n Large momentum range acceptance Good transmission Small footprint High intensities Duty cycle approaching 50%

Thank You