Author Institution: Los Alamos National Laboratory, Physics DivisionSlides presented at the 2016 Photonic Doppler Velocimetry (PDV) unclassified program, Bankhead Theater, Livermore, California, June 7 - 9, 2016. Morning program, June 7, 2016

Holtkamp, David

Neukirch, Levi

Rae, Philip

Tainter, Amy

Tupa, Dale

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PDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthThe Los Alamos Proton Radiography Facility (pRad) employs a high-energy proton beam to image the properties and behavior of materials driven by high explosives. We will discuss features of pRad and describe some recent experiments, highlighting optical diagnostics for surface velocity measurements.Dale Tupa, Amy Tainter, Levi Neukirch, Philip Rae, David HoltkampPhysics Division, Los Alamos National LaboratoryPDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthLANSCE:Los Alamos Neutron Science CenterPDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthIsotope Production FacilityMedical radioisotopesLujan CenterNational security researchMaterials, bio-science, and nuclear physics National user facilityWNRNational security researchNuclear Physics Neutron IrradiationProton RadiographyNational security researchDynamic Materials scienceHydrodynamicsPDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth PDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth PDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth PDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth PDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthPDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthDetectorObjectMagnetic LensSimple “shadow” image – results are substantially blurred.Magnetic imaging of the protons preserves high resolution.  (Los Alamos 1995)PDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthHigh-speed radiographic movies!Proton pulse timing sequences can be specified by the experimenterExperiment Principal Investigator: Billy ButtlerPDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthPDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthExperiment Principal Investigator: Russ OlsonPDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthmoviePDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthPDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthPDV: Photon Doppler VelocimetryPDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthNew hardware implementations towards several goals:(1) Miniaturize PDV hardware(2) Reduce total cost per channel (3) Reduce digitizer bandwidth requirementsPDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth(1) Miniaturize PDV hardwareReplace rack-mounted EDFA lasers with single frequency laser diodes and tapered amplifiers.Goal: “Small as a deck of cards”(2) Reduce total cost per channelAdd a 1310nm-based PDV; overlay signal with 1550nm PDVPDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthDemonstration that dual-wavelengths and tapered amplifier technologies work for PDV applicationPDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth(3) Reduce digitizer bandwidth requirements. For 1550 nm, PDV signal is 1.3 GHz per km/s speedElectrical heterodyning produces signal at fLO ± fsigPDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth(3) Reduce digitizer bandwidth requirements:Electrical heterodyning produces signal at fLO ± fsigPDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth(3) Reduce digitizer bandwidth requirements:Electrical heterodyning produces signal at fLO ± fsigNormal PDV on Ch. 1Down-mixed PDV on Ch 2PDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth(3) Reduce digitizer bandwidth requirements:Electrical heterodyning requires recording multiple bands of frequency offset. Alternative approach: reduce constant for velocity/GHzNormal PDV on Ch. 1PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth(3) Reduce digitizer bandwidth requirements:Reduce signal frequency per given speedNormal PDV on Ch. 1Δf1550 ≈ 1.3 GHz/km/sΔf1310 ≈ 1.5 GHz/km/s(Δf1310 - Δf1550) ≈  237 MHz/km/sPDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth(3) Reduce digitizer bandwidth requirements:Reduce signal frequency per given speedNormal FFT1310 signal1550 signalFFT of signal squared Beat signal(Δf1310 - Δf1550) ≈  237 MHz/km/sPDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth(3) Reduce digitizer bandwidth requirements:Decode digitizer “alias” with two laser frequenciesUndersampling a periodic function produces aliasingTrue SignalAliased MeasurementPDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth(3) Reduce digitizer bandwidth requirements:Decode digitizer “alias” with two laser frequenciesSampled at 312 MS/s Sampled at 100 MS/sNyquist frequencyPDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthfsignal = Nfs ± fMN = ???Measured spectrumamplitudefrequencyamplitudefsfN = 0.5 fsfsignal = fMfsignal = fs - fMfsignal = fs + fMfsignal = 2fs - fM1.5 fsfMfMfMMultiple spectra can result in a single measured spectrumfM = Measured spectrumfS = Scope bandwidthfN = Nyquist frequencyPDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth(3) Reduce digitizer bandwidth requirements:Decode digitizer “alias” with two laser frequencies1310 signal1550 signalPDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth(3) Reduce digitizer bandwidth requirements:Decode digitizer “alias” with two laser frequencies1310 signal1550 signaldigitizer aliasingPDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth(3) Reduce digitizer bandwidth requirements:Decode digitizer “alias” with two laser frequenciesPDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth(3) Reduce digitizer bandwidth requirements:Decode digitizer “alias” with two laser frequencies1310 nm signal reflects six times, therefore using 7*BW1550 nm signal reflects five times, using 6*BWPDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidth(3) Reduce digitizer bandwidth requirements:Decode digitizer “alias” with two laser frequenciesKnowing that both signals represent the same velocity yields one unique solution for any given timePDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthOZ Optics MEMS-based voltage controlled attenuatorsSingle-channel Eight-channelPDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthOZ Optics MEMS-based voltage controlled attenuators→ Low voltage, 0-6V→ Low power electrical power consumption (<10 mW)→ High optical power handling, up to 500 mW→ Repeatable (negligible hysteresis)→ Available with built in power monitoring→ No new optical noisePDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthConclusions: There is ongoing development on PDV at the LANL Proton Radiography facility to make the diagnostic:(1) Smaller(2) Lower cost, for opto/electronics(3) Available at digitizer bandwidths attainable on a university budgetPDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthPDV Workshop 2016PDV development at the LANL Proton Radiography Facility: smaller, cheaper, lower bandwidthVelocimetry contributions: Dale Tupa, Amy Tainter, Levi NeukirchPhilip Rae, David Holtkamp, Brian Glover, Jake GundersonProton Radiography team: M. Freeman, B. J. Hollander, J. D. Lopez, F. G. Mariam, M. J. Martinez, J. J. Medina, P. V. Medina, D. Morley, C. L. Morris, M. M. Murray, L. Neukirch, A. Saunders, T. Schurman, T. Sisneros, A. Tainter, F. Trouw, D. Tupa, A. Vera, J. Goett, F. E. Merrill, P. Nedrow, R. Simpson, J. Tybo, C. J. Wilde, J. C. Allison, W. V. McNeil, P. D. Scott, C. R. Valdez, S. W. Vincent, J. Strotman, C. R. LopezExperiment P.I.s: B. Buttler, R. Olson

PDV Development at the LANL Proton Radiography Facility: Smaller, Cheaper, Lower Bandwidth

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PDV Development at the LANL Proton Radiography Facility: Smaller, Cheaper, Lower Bandwidth

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