UNCLASSIFIED Helium-3 Alternative Technologies Dr. Hank Zhu Program Manager U.S. Defense Threat Reduction Agency Email: [email protected] NuSec, April 15-16, 2019 Approved for public release, distribution is unlimited UNCLASSIFIED UNCLASSIFIED Background Information 3He is a rare isotope with important uses in: . Neutron detection . Lung imaging science oil/gas exploration . Missile guidance national security construction . safeguards industrial applications Laser research . Low-temperature physics . Fusion U.S. Tritium production ended in 1988, with 200,000 liters of 3He stockpile by end of 1990s In 2008, the projected 3He supply is 10-20 kL/y, v.s. demand 65 kL/y: Canberra built SRNL “WAS” contains > 1,400 liters of 3He In 2009, NSS setup an interagency policy committee to address supply shortage and restrict distributions In 2009, IPT for 3He alternative technologies includes DHS/DNDO, DTRA, DOE/NNSA UNCLASSIFIED UNCLASSIFIED DTRA-Sponsored Neutron Detection Technologies * Technology * Low-Cost/Mass Manufacturing * Applications Proportional Counter: • Boron-Coated Straw (BCS) • Li-6 Foil Multi-Wire Proportional Counter Semiconductor: • Microstructured Semiconductor Neutron Detector (MSND) Scintillators: • Cs-Li- Elpasolites: • Organic Scintillators: Cs2LiYCl6:Ce (CLYC) Tin-loaded PSD Plastics Cs2LiLaCl6:Ce (CLLC) Boron-loaded PSD Plastics Cs2LiLaBr6:Ce (CLLB) • Tl-Li-Elpasolites: Cs2LiLa(Br,Cl)6 (CLLBC) Tl2LiYCl6:Ce (TLYC) Tl2LiLaBr6 (TLLB), Tl2LiLa(Br,Cl)6 (TLLBC) UNCLASSIFIED UNCLASSIFIED Boron-Coated Straws (BCS) Small-diameter Proportional Counter ← Thermal neutron by Proportional Technologies Inc. detection efficiency of dense array of round straws (any diameter, unmoderated) By comparison, the efficiency of a 1-inch 3He tube at 5-atm is 73%. Straws can assume different configurations (tube shape & diameter) and lengths, as pictured, for thermal and fast neutron detection. Corrugated walls (star shapes) and inner septa achieve higher efficiencies than round straws. Straws embedded in polyethylene for fast Individually sealed Straw bundles Straws with inner coated septa neutron detection UNCLASSIFIED UNCLASSIFIED BCS Production Low-Cost, Continuous Mass Manufacturing: 2 1 Boron-coated copper film Automatic straw winding/welding/cutting Finished straws 3 Nonstop reel-to-reel boron coating Wiring and sealing inside aluminum tube UNCLASSIFIED UNCLASSIFIED BCS Applications in Nuclear Security Personal Monitor / Dosimeter Direction-finding/ Spectroscopic monitor Portable fission counter Coincidence counter Backpack / Vest Monitor Portal Monitor Vehicle-Mounted UNCLASSIFIED UNCLASSIFIED BCS Applications in Neutron Science Neutron imaging panel (5-layer) tested at the China Spallation Spallation Neutron Neutron Source (CSNS) Source (Oak Ridge purchased 5-layer National Lab) panel and completed acceptance testing (Jan 2019) Annular counter beam (1152 straws, 1-m long) for tomographic imaging of nuclear fuel assemblies (Oak Ridge National Lab) UNCLASSIFIED UNCLASSIFIED Microstructured Semiconductor Neutron Detector (MSND) • State-of-the-art micropatterned silicon 6 diodes backfilled with LiF neutron α conversion material by: Neutron- Conversion t Kansas State University α Silicon Mateiral 2 • 1-cm area, 0.5- to 1.5-mm thick Silicon α t Silicon t detectors MSND • Single-Sided MSND DS-MSND • 35% intrinsic thermal neutron detection efficiency • >1:106 gamma-ray rejection ratio • Dual-Sided MSND • >60% intrinsic thermal neutron detection efficiency • 69.2±0.8% highest detection-efficiency achieved • 1:106 gamma-ray rejection ratio 3 *Assumes 100-keV LLD for He Detectors UNCLASSIFIED UNCLASSIFIED MSND Manufacturing • Mass producible with common semiconductor processing equipment • Cost-effective via large Si VLSI industry • Up to 50 wafers processed simultaneously • 50 wafers yields ~ 2100 MSNDs • Made from readily available materials • Silicon, 6LiF, common discrete electronics • MSNDs can operate individually or arrayed into larger detector packages • MSND cost-to-consumer ~$80/MSND-cm2, commercialized by: Radiation Detection Technologies, Inc. UNCLASSIFIED UNCLASSIFIED MSND Applications • Modular Neutron Detector (MND) • 24 MSNDs or DS-MSNDs in cell-phone-sized package • Wireless or wired operation • Operate standalone or 16-MND wearable detector system • Portable Imaging Neutron Gamma Spectrometer PINGS • PINGS – high fidelity instrument for search, locate, identify, and dosimetry missions • DOMINO® Neutron Detector • 4-cm2 active area detectors with active-readout electronics, that can be chained to form long strips up to 1-m long • Direct 3He replacement modules • Swap-in replacements for 2-in. dia., 4-atm 3He and 0.75-in. dia., 10-atm 3He detectors • Other Customers • Have supplied MSNDs for DoD, NASA, DOE, NSF, etc. • International Industry: homeland security, health, fusion, etc. Contact: Steven Bellinger, [email protected], (785)-532-7087 UNCLASSIFIED UNCLASSIFIED Cs-Li-Elpasolite Scintillators 3+ 3+ - - - Cs2Li(RE)X6:Ce: RE – Rare Earth Ions (e.g. Y , La ), X – Halide Ions (Cl , Br , I ) Cs2LiYCl6:Ce (CLYC), Cs2LiLaCl6:Ce (CLLC), Cs2LiLaBr6:Ce (CLLB), Cs2LiLa(Br,Cl)6 (CLLBC) Radiation Monitoring Devices, Inc. Scintillator CLYC CLLC CLLB CLLBC Density 3.3 3.4 4.2 >4 Zeff 45 46 47 47 Light Yield (γ-ray) (ph/MeV) 18,000 35,000 45,000 42,000 Light Yield (neutron) (ph/neutron) 70,000 110,000 135,000 130,000 Emission Wavelength (nm) 370 390 410 400 Decay Times (ns) 60-5500 90-1500 55-1500 115-1500 ER (at 662keV) 4-5% 4% 3% 3% GEE for Thermal Neutron (MeV) 3.2 3.1 3 3 n0 Efficiency (at 1.5 cm) 80% 80% 90% 85% -n PSD FOM >4 >3 ~2 >3.3 Fast Neutron Spectroscopy Yes Yes No Yes UNCLASSIFIED UNCLASSIFIED Cs-Li-Elpasolite Scintillation Properties Non-Proportionality Energy Resolution 1.2 NaI:Tl LaBr :Ce 3 1.1 CLYC:Ce CLLBC:Ce Cs Am Co 1.0 Co Na Cs Na 0.9 All crystals are 1”x1” right cylinders Relative light yield 10 100 1000 Energy, keV Pulse-Shape Discrimination 1.2 window 1 window 2 neutron 1.0 gamma windows 0.8 0.6 neutron 0.4 counts, arb. units 0.2 gamma 0.0 0 200 400 600 time, ns UNCLASSIFIED UNCLASSIFIED Fast Neutron Detection with 35Cl: Tri-Mode Detector • Linear function of 1n energy 35 1 1 35 Cl + n p + S + energy • Clear full energy peaks • Possible spectroscopy 600 893 keV 500 1202 keV 1508 keV C 400 o 1913 keV u 300 n t 200 s 100 0 2 0 0 400 600 800 1000 Channel C 600 h a 6 400 Li(nth,a) – Region B n n 35 e 200 Cl(nf,p) – Region C l 0 6Li/35Cl(n ,a) – Region D 0 500 1000 1500 2000 f Energy (keV) UNCLASSIFIED UNCLASSIFIED Elpasolites Production Facility Production furnaces Larger furnaces Up to 3” dia. Crystals up to 4.5” dia. Crystals Additional furnaces can be added with 4-month lead time to support increased demand Glove boxes for loading and packaging Dry Room for crystal cutting and lapping UNCLASSIFIED UNCLASSIFIED CLYC-based Products CLYC 3” CLYC + PMT Products SPRD Detectors with CLYC + SiPM Product launch Jan. 2013 Product launch Aug. 2016 Non-spectroscopic RIIDEye RadEye GN+ RadEye SPRD-GN UNCLASSIFIED UNCLASSIFIED CLYC-based He-3 Replacement Detector Specifications: Size: 1” x 1” x 9.0” Weight: 250 g Neutron efficiency >30 cps/nv (3 x modules) Power supply: 50mA @ 3 to 6V Technology: Array of Cs2LiYCl6:Ce (CLYC) scintillators packaged in aluminum tubes to retrofit high pressure He-3 tubes • Sensitivity comparable to 20 atm He-3 tubes with similar dimensions • Full solid state construction: CLYC with SiPMs • High neutron GEE = 3.4 MeV, i.e. effective PHD Centronic 3He Tube vs. Dimensions Sensitivity • PSD for gamma discrimination > 107 CLYC Replacement • Modular design, configurable sensitivity to 15He3/1520/25HS (20 atm) Ø 1” × 8.67” 28 cps/nv meet the requirements RMD-3 sub-modules, 1” × 9.00” 30 cps/nv • Configurable output – USB / SPI / TTL 14cc each UNCLASSIFIED UNCLASSIFIED Successful Scale-Up of CLLBC 2.0 Ø1inch CLLBC:Ce 137 Ø1.5inch Cs spectra 1.5 Ø2inch R ~ 3.0% 1.0 0.5 Intensity (arb. units) 0 200 400 600 800 Energy (keV) UNCLASSIFIED UNCLASSIFIED 1.5” CLLBC with SiPMs 3 137 CLLBC Ø1.5inch Cs spectrum Detector packaged with SiPMs R ~ 3.5% 2 1 Intensity (counts/s) 0 0 200 400 600 800 Energy (keV) UNCLASSIFIED UNCLASSIFIED From CLYC to TLYC Tuning: Cs2Li(RE)X6 Tl2Li(RE)X6 Considerable increase in gamma-ray stopping power 662 keV 662 keV Density Attn. Material Z photo- eff (g/cc) Length fraction (cm) NaI:Tl 50 3.67 0.1 3.6 LaBr3 47 5.1 0.08 2.6 Cs2LiYCl6 45 3.3 0.08 3.9 Tl2LiYCl6 69 4.5 0.25 2.4 UNCLASSIFIED UNCLASSIFIED TLYC Performance: 1”x1” Crystals 1.2 PSD FOM ~ 2.4 1.1 Co Na Am NaCs 1.0 Cs TLYC:Ce 0.9 NaI:Tl LaBr :Ce Relative light yield 3 0.8 100 1000 Energy, keV UNCLASSIFIED UNCLASSIFIED Comparison of CLYC, CLLBC, TLYC Scintillator CLYC CLLBC TLYC Density 3.31 4 4.58 Zeff 45 47 69 Photo-fraction at 662 keV 0.08 0.09 0.25 Light Yield (γ-ray) 18,000 42,000 ~30,000 (ph/MeV) Emission Wavelength (nm) 370 410 440 Decay Times (ns) 60-5500 115-1500 57-1171 Energy Resolution 4-5% 3% 3-4% (at 662keV) GEE for thermal n (MeV) 3.2 3.1 2 n0 Efficiency (at 1.5 cm) 80% 85% 82% -n PSD FOM >4 3.5 ~2 Fast Neutron Spectroscopy Yes Yes Yes UNCLASSIFIED UNCLASSIFIED Tin-loaded Plastic Scintillator 3” x 3” Plastic Scintillator Light yield ~ 12,000 ph/MeV, Energy resolution ~ 10% loaded with Organometallic Tin T ~ 25C 280 260 252 moderated - Cf neutron 252Cf source gamma 260 n: 240 Gamma 240 220 ratio PSD 220 Fast neutrons 200 window 2 / window 1 Tin-loaded plastic FOM ~ 1.5 @ 1 MeVee 180 200 0 100 200 300 0 1000 2000 3000 4000 5000 full integral Counts UNCLASSIFIED UNCLASSIFIED Summary • DTRA