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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,351 records · Page 75
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Muon flux measurement at China Jinping Underground Laboratory

China Jinping Underground Laboratory (CJPL) is ideal for studying solar, geo-, and supernova neutrinos. A precise measurement of the cosmic-ray background is essential in proceeding with R&D research for these MeV-scale neutrino experiments. Using a 1-ton prototype detector for the Jinping Neutrino Experiment (JNE), we detected 264 high-energy muon events from a 645.2-day dataset from the first phase of CJPL (CJPL-I), reconstructed their directions, and measured the cosmic-ray muon flux to be $(3.53\pm0.22_{\rm{stat.}}\pm0.07_{\rm{sys.}})\times10^{-10}$ cm $^{-2}$s $^{-1}$. The observed angular distributions indicate the leakage of cosmic-ray muon background and agree with simulation data accounting for Jinping mountain's terrain. A survey of muon fluxes at different laboratory locations, considering both those situated under mountains and those down mine shafts, indicates that the flux at the former is generally a factor of $(4\pm2)$ larger than at the latter, with the same vertical overburden. In conclusion, this study provides a convenient back-of-the-envelope estimation for the muon flux of an underground experiment.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2023

Measurement of the top quark-antiquark pair charge asymmetry in events with highly boosted top quarks in proton-proton collisions at 13 TeV with the CMS detector

The top quark is the heaviest elementary particle, making it a unique tool to search for new physics. In this talk, I will present a new measurement of the top quark pair charge asymmetry for highly boosted top quarks decaying to a single lepton, missing transverse momentum and jets. The analysis is performed on 13TeV proton-proton collision data recorded by the CMS experiment during Run 2. We have defined a dedicated phase space that selects top quark-antiquark pairs with invariant mass greater than 750GeV in a semileptonic final state where the lepton is not necessarily isolated. This highly boosted sample is enhanced in valence quark production and thus expected to be more sensitive to deviations in the charge asymmetry caused by BSM processes. Dedicated tagging techniques are used to identify the decay products of hadronic top quarks and W bosons. An unfolding procedure is used to correct for detector resolution and acceptance, and inefficiencies in the event reconstruction. The result is presented in the full phase space at parton level and can be used as input to global EFT interpretations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Screening and Spectral Summing of LANL Empty Waste Drums - 13226

Empty 55-gallon drums that formerly held transuranic (TRU) waste (often over-packed in 85- gallon drums) are generated at LANL and require radiological characterization for disposition. These drums are typically measured and analyzed individually using high purity germanium (HPGe) gamma detectors. This approach can be resource and time intensive. For a project requiring several hundred drums to be characterized in a short time frame, an alternative approach was developed. The approach utilizes a combination of field screening and spectral summing that was required to be technically defensible and meet the Nevada Nuclear Security Site (NNSS) Waste Acceptance Criteria (WAC). In the screening phase of the operation, the drums were counted for 300 seconds (compared to 600 seconds for the typical approach) and checked against Low Level (LL)/TRU thresholds established for each drum configuration and detector. Multiple TRU nuclides and multiple gamma rays for each nuclide were evaluated using an automated spreadsheet utility that can process data from up to 42 drums at a time. Screening results were reviewed by an expert analyst to confirm the field LL/TRU determination. The spectral summing analysis technique combines spectral data (channel-by-channel) associated with a group of individual waste containers producing a composite spectrum. The grouped drums must meet specific similarity criteria. Another automated spreadsheet utility was used to spectral sum data from an unlimited number of similar drums grouped together. The composite spectrum represents a virtual combined drum for the group of drums and was analyzed using the SNAP{sup TM}/Radioassay Data Sheet (RDS)/Batch Data Report (BDR) method. The activity results for a composite virtual drum were divided equally amongst the individual drums to generate characterization results for each individual drum in the group. An initial batch of approximately 500 drums were measured and analyzed in less than 2 months in 2011. A second batch of approximately 500 more drums were measured and analyzed during the following 2 1/2 months. Four different HPGe detectors were employed for the operation. The screening and spectral summing approach can reduce the overall measurement and analysis time required. However, developing the technical details and automation spreadsheets requires a significant amount of expert time prior to beginning field operations and must be considered in the overall project schedule. This approach has continued to be used for characterizing several hundred more empty drums in 2012 and is planned to continue in 2013. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Constraints on neutrino oscillation parameters with the NOvA experiment

NOvA is a long-baseline neutrino oscillation experiment, which consists of two finely-segmented liquid-scintillator detectors operating 14 mrad off-axis from the NuMI muon neutrino beam. With an 810 km baseline, the combined measurements of muon neutrino disappearance and electron neutrino appearance allow the determination of neutrino oscillation unknowns, namely the mass hierarchy, the octant of the largest neutrino mixing angle, and the CP violating phase. In this dissertation I present the joint analysis of $\nu_\mu \to \nu_\mu$ and $\nu_\mu \to \nu_e$ oscillation data with an exposure of $8.85\times10^{20}$ protons on target on the 14 kton detector. It includes the estimation of neutrino energy distributions in the far detector using near detector data constraints, details of the implementation of the simultaneous fit of \numu and \nue samples, and the effect of systematic uncertainties on the measurement of oscillation parameters. I also discuss NOvA's projected sensiti vity to determine the mass hierarchy and discover CP violation in future analyses with increased exposure and the addition of antineutrino datasets. With 66 electron neutrino and 126 muon neutrino candidates, the best fit to the data corresponds to the normal mass hierarchy, $\Delta m^2_{32}=2.44\times 10^{-3} eV^2/c^4$, $\sin^2 \theta_{23}=0.56$, and $\delta_{CP} = 1.21\pi$, with the allowed regions $\Delta m^2_{32} \in [2.37,2.52]\times 10^{-3} eV^2/c^4$, $\sin^2 \theta_{23} \in [0.43,0.51] \cup [0.52,0.60]$ and $\delta_{CP} \in [0,0.12\pi] \cup [0.91\pi,2\pi]$ at the 68.3\% C.L. Our data disfavor maximal mixing by 0.8$\sigma$, $\delta_{CP} = \pi/2$ in the inverted hierarchy at higher than 3$\sigma$, and the entire inverted mass hierarchy at the 95\% confidence level. % By increasing the size of the samples and adding anti-neutrino data, \nova can potentially resolve the neutrino mass hierarchy at 4$\sigma$ C.L. or higher for some combinations of oscillation parameters. Im provements to the sensitivity to the determination of the ma! ss hierarchy and CP violation in the neutrino sector can be achieved through gains in the NuMI beam intensity, the inclusion of external data, and refinements in the analysis methodology.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2026

Lunar accelerometer network gravitational observatory (LANGO)

With ground-based interferometers detecting hundreds of gravitational-wave (GW) events, GW astronomy has continued to blossom. U.S. and European scientists are developing plans to construct third-generation ground-based interferometers. ESA has proceeded through the mission formulation phase of space-based interferometer in a lower-frequency band, 10 –4 –0.1 Hz. Despite all these exciting developments, there is still a missing frequency band, 0.1–10 Hz. This mid-frequency band is rich with interesting astrophysical events. Coalescence and merger of intermediate-mass black holes (IMBHs) will occur in this frequency band. Coalescing stellar-mass BHs will pass through this frequency band days before they reach the frequency band of LIGO and Virgo. Detection of such signals would enable a mid-frequency detector to issue an advance notice to the high-frequency GW detectors, as well as to optical, x-ray and γ-ray telescopes. We propose Lunar Accelerometer Network Gravitational Observatory (LANGO) to detect GWs in this frequency band. In the first phase (LANGO 1), we propose to deploy four ambient-temperature (250 K) accelerometers in the tetrahedral or in a square configuration on the hemisphere facing the Earth. After successful operation at 250 K, LANGO would be upgraded to a cryogenic (4 K) version with over two orders of magnitude increased sensitivity (LANGO 2), with coherent rejection of seismic noise implemented. LANGO is a full-tensor detector, capable of determining the source direction and wave polarization. Each test mass (TM) is suspended as a pendulum with resonance frequency ∼ 0.01 Hz, thus is only weakly coupled to the lunar surface horizontally. LANGO is designed to detect the relative motion of globally separated, nearly free, TMs by using the Moon as a large quiet platform. LANGO 1 and 2 accelerometers aim at sensitivities ⩽ 10 –11 m s –2 Hz –1/2 and ⩽ 10 –13 m s –2 Hz –1/2 in the horizontal axes over the frequency band of 1 mHz–10 Hz, which yield GW sensitivities 1.1 x 10 -21 Hz -1/2 and 3.8 x 10 -24 Hz -1/2 at 1 Hz, respectively. The LANGO accelerometers will be 10 3 –10 5 times more sensitive than Apollo seismometers. With such sensitivity, LANGO will also make great contribution to the advancement of lunar geophysics.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Measurement of the integrated luminosity of the Phase 2 data of the Belle II experiment

From April to July 2018, a data sample at the peak energy of the Υ(4S) resonance was collected with the Belle II detector at the SuperKEKB electron-positron collider. This is the first data sample of the Belle II experiment. Using Bhabha and digamma events, we measure the integrated luminosity of the data sample to be (496.3±0.3±3.0)pb –1 , where the first uncertainty is statistical and the second is systematic. This work provides a basis for future luminosity measurements at Belle II.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Three-dimensional Image Fusion Guidance for Transjugular Intrahepatic Portosystemic Shunt Placement

IntroductionTo assess the safety, feasibility and effectiveness of image fusion guidance with pre-procedural portal phase computed tomography with intraprocedural fluoroscopy for transjugular intrahepatic portosystemic shunt (TIPS) placement.Materials and methodsAll consecutive cirrhotic patients presenting at our interventional unit for TIPS creation from January 2015 to January 2016 were prospectively enrolled. Procedures were performed under general anesthesia in an interventional suite equipped with flat panel detector, cone-beam computed tomography (CBCT) and image fusion technique. All TIPSs were placed under image fusion guidance. After hepatic vein catheterization, an unenhanced CBCT acquisition was performed and co-registered with the pre-procedural portal phase CT images. A virtual path between hepatic vein and portal branch was made using the virtual needle path trajectory software. Subsequently, the 3D virtual path was overlaid on 2D fluoroscopy for guidance during portal branch cannulation. Safety, feasibility, effectiveness and per-procedural data were evaluated.ResultsSixteen patients (12 males; median age 56 years) were included. Procedures were technically feasible in 15 of the 16 patients (94%). One procedure was aborted due to hepatic vein catheterization failure related to severe liver distortion. No periprocedural complications occurred within 48 h of the procedure. The median dose-area product was 91 Gy cm{sup 2}, fluoroscopy time 15 min, procedure time 40 min and contrast media consumption 65 mL. Clinical benefit of the TIPS placement was observed in nine patients (56%).ConclusionThis study suggests that 3D image fusion guidance for TIPS is feasible, safe and effective. By identifying virtual needle path, CBCT enables real-time multiplanar guidance and may facilitate TIPS placement.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
NASA NTRS1992

Onset of dispersion in Nb microstrip transmission lines at submillimeter wave frequencies

We have measured the dispersion in phase velocity of a Nb-SiO(x)-Nb microstrip transmission line resonator over a frequency range from 50 GHz to 800 GHz. A submicron Nb/Al-AlO(x)/Nb Josephson junction was used as a voltage-controlled oscillator to excite the high order modes in the resonator. The same junction is used as a direct detector resulting in a series of step-like structures in the DC current-voltage characteristic at the position of each mode frequency. The transmission line is dispersionless up to about 500 GHz where the phase velocity begins to decrease. This is well below the gap frequency f(sub g) approx. equals 700 GHz. Results agree qualitatively with the expected theoretical behavior near f(sub g). This onset of dispersion and loss in Nb transmission lines will have a significant impact on the design of submillimeter wave RF circuits.

Javadi, H. H. S.↗
DOE OSTI2013

The Design of an Ultra-Low Background Thermosyphon for the Majorana Demonstrator

The MAJORANA DEMONSTRATOR (MJD) is an ultra-low background neutrinoless double-beta decay (0νββ) experiment that will deploy up to 40 kg of high purity germanium detectors (HPGe). The goal of this experiment is to demonstrate the feasibility of building a detector array with less than 1 event/ton-year in a 4 keV region of interest around the 0νββ signal. HPGe diodes, when used as ionizing radiation detectors, need to be maintained at a temperature close to that of liquid nitrogen (77 K). This work describes the R&D results of a cryogenic system capable of meeting the requirements of low background and the cooling capacity required to successfully operate such a detector system. The MJD germanium detector modules will operate at liquid nitrogen temperature to provide adequate cooling for a full range of HPGe impurity concentrations. This paper shows the experimental results obtained using a two-phase horizontal thermosyphon using liquid nitrogen as the MJD’s cooling system. The cold test shows that the proposed thermosyphon has sufficient cooling power to handle the heat load of an MJD module. Results for the temperature gradient across the thermosyphon, cooling capacity, and design considerations demonstrate that the thermosyphon can effectively remove the calculated heat load of each module of the experiment. The thermosyphon will be bolted to a cold plate from which detector strings will hang. The thermal conductivity of a mockup of the MJD bolted thermal joint is experimentally determined to be below 0.1 K/W.

Detector arrays↗
DOE OSTI2024

A novel high frequency, high bandwidth, three phase Mach–Zehnder optical data link

In inertial confinement fusion, hydrogen isotopes are fused together under high pressures and temperatures. Typically, the duration of these experiments is incredibly short, on the order of around 60–150 ps. Due to the high radiation environment, a detector’s signal is typically data linked far distances to a protected location. The diagnostic challenge for fusion reaction history measurements is to measure signals of interest maximizing dynamic range while also maintaining time resolution on the order of 10 ps. In this work, we present a new experimental optical data link used to efficiently transport diagnostic signals over great distances to the recording system while not restricting the dynamic range. The concept of a three phase Mach–Zehnder modulator system is introduced as well as a description of the physical prototype. The initial results from testing at the OMEGA facility show that this system is a viable method for signal transportation.

47 OTHER INSTRUMENTATION↗
DOE OSTI2016

Experimental particle physics research at Texas Tech University

The high energy physics group at Texas Tech University (TTU) concentrates its research efforts on the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) and on generic detector R&D for future applications. Our research programs have been continuously supported by the US Department of Energy for over two decades, and this final report summarizes our achievements during the last grant period from May 1, 2012 to March 31, 2016. After having completed the Run 1 data analyses from the CMS detector, including the discovery of the Higgs boson in July 2012, we concentrated on commissioning the CMS hadron calorimeter (HCAL) for Run 2, performing analyses of Run 2 data, and making initial studies and plans for the second phase of upgrades in CMS. Our research has primarily focused on searches for Beyond Standard Model (BSM) physics via dijets, monophotons, and monojets. We also made significant contributions to the analyses of the semileptonic Higgs decays and Standard Model (SM) measurements in Run 1. Our work on the operations of the CMS detector, especially the performance monitoring of the HCAL in Run 1, was indispensable to the experiment. Our team members, holding leadership positions in HCAL, have played key roles in the R&D, construction, and commissioning of these detectors in the last decade. We also maintained an active program in jet studies that builds on our expertise in calorimetry and algorithm development. In Run 2, we extended some of our analyses at 8 TeV to 13 TeV, and we also started to investigate new territory, e.g., dark matter searches with unexplored signatures. The objective of dual-readout calorimetry R&D was intended to explore (and, if possible, eliminate) the obstacles that prevent calorimetric detection of hadrons and jets with a comparable level of precision as we have grown accustomed to for electrons and photons. The initial prototype detector was successfully tested at the SPS/CERN in 2003-2004 and evolved over the last decade. In 2012-2015, several other prototypes were built to further reduce leakage fluctuations, improve Cherenkov light yield, increase fiber attenuation length, and other related phenomena. During this grant period, we graduated two students with Ph.D. degrees, and five undergraduate students from our labs went on to prestigious graduate programs in the US and Europe. Also, the TTU HEP team has participated in the QuarkNet program every year since 2001. We are dedicated to working with area teachers and students at all levels and to training the next generation of scientists. Over 20 high school teachers have participated in our program since its inception.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2022

Measurement and QCD analysis of double-differential inclusive jet cross sections in proton-proton collisions at $\sqrt{s}$ = 13 TeV

A measurement of the inclusive jet production in proton-proton collisions at the LHC at $ \sqrt{s} $ = 13 TeV is presented. The double-differential cross sections are measured as a function of the jet transverse momentum p$_{T}$ and the absolute jet rapidity |y|. The anti-k$_{T}$ clustering algorithm is used with distance parameter of 0.4 (0.7) in a phase space region with jet p$_{T}$ from 97 GeV up to 3.1 TeV and |y| < 2.0. Data collected with the CMS detector are used, corresponding to an integrated luminosity of 36.3 fb$^{-1}$ (33.5 fb$^{-1}$). The measurement is used in a comprehensive QCD analysis at next-to-next-to-leading order, which results in significant improvement in the accuracy of the parton distributions in the proton. Simultaneously, the value of the strong coupling constant at the Z boson mass is extracted as α$_{S}$(m$_{Z}$) = 0.1170±0.0019. For the first time, these data are used in a standard model effective field theory analysis at next-to-leading order, where parton distributions and the QCD parameters are extracted simultaneously with imposed constraints on the Wilson coefficient c$_{1}$ of 4-quark contact interactions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Amplitude analysis and branching fraction measurement of $D_s^+$ →$K^–K^+π^+π^+π^–$

Using $e^+e^–$ annihilation data corresponding to a total integrated luminosity of 6.32 fb –1 collected at the center-of-mass energies between 4.178 and 4.226 GeV with the BESIII detector, we perform an amplitude analysis of the decay $D_s^+$ →$K^–K^+π^+π^+π^–$ and determine the relative fractions and phases of different intermediate processes. Absolute branching fraction of $D_s^+$ →$K^–K^+π^+π^+π^–$ decay is measured to be (6.60 ± 0.47 stat. ± 0.38 syst. ) x 10 –3 . The dominant intermediate process is $D_s^+$ → $a_1$(1260) + $\phi, \phi$ → $K^–K^+ a_1$(1260) + → $ρπ^+$, $ρ → π^+π^–$, with a branching fraction of (5.15 ± 0.41 stat. ± 0.32 syst. ) x 10 –3 .

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Investigation of structure, morphology and orientation of precipitates in Mg−Bi alloy

Highlights: • Rod-shaped, cuboid-shaped and polyhedral α-Mg{sub 3}Bi{sub 2} are found in MgBi alloy. • The two orientation relationships between Mg{sub 3}Bi{sub 2} and Mg matrix are confirmed. • Growth of rod-shaped Mg{sub 3}Bi{sub 2} is fast along 〈10 1-bar 0〉 direction of precipitate. • Interfacial matching between polyhedral Mg{sub 3}Bi{sub 2} and Mg matrix is the best. - Abstract: In Mg−0.8 at.% Bi binary alloys,the structure, the morphology and the orientation of precipitates were characterized by high-resolution transmission electron microscopy (HRTEM) and high-angle annular dark detector field scanning transmission electron microscopy (HAADF−STEM) techniques. The main precipitate is the α-Mg{sub 3}Bi{sub 2} phase with hexagonal structure (P 3-bar m1). The morphology of α-Mg{sub 3}Bi{sub 2} precipitate is classified into three types, rod-shaped, cuboid-shaped and polyhedral, which are related closely with orientation relationships (ORs) between α-Mg{sub 3}Bi{sub 2} precipitate and αMg matrix. For the first two types of morphologies, precipitate and αMg matrix can maintain the following ORs: [11 2-bar 0]{sub Mg{sub 3Bi{sub 2}}}//[0001]{sub Mg} and (1 1-bar 00){sub Mg{sub 3Bi{sub 2}}}//(1 1-bar 00){sub Mg}. In contrast, another set of ORs between polyhedral α-Mg{sub 3}Bi{sub 2} and αMg matrix can be determined as: [11 2-bar 0]{sub Mg{sub 3Bi{sub 2}}}//[11 2-bar 0]{sub Mg} and (0003){sub Mg{sub 3Bi{sub 2}}}//(1 1-bar 01){sub Mg}. The morphology of α-Mg{sub 3}Bi{sub 2} precipitates is discussed particularly based on the interfacial misfit mechanism.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Measurement of cross sections for production of a $Z$ boson in association with a flavor-inclusive or doubly $b$-tagged large-radius jet in proton-proton collisions at $\sqrt{s}$ = $13$ $\mathrm{TeV}$ with the ATLAS experiment

We present measurements of cross sections for production of a leptonically decaying $Z$ boson in association with a large-radius jet in 13 TeV proton-proton collisions at the LHC, using 36 fb –1 of data from the ATLAS detector. Integrated and differential cross sections are measured at particle level in both a flavor inclusive and a doubly $b$-tagged fiducial phase space. The large-radius jet mass and transverse momentum, its kinematic relationship to the Z boson, and the angular separation of $b$-tagged small-radius track jets within the large-radius jet are measured. This measurement constitutes an important test of perturbative quantum chromodynamics in kinematic and flavor configurations relevant to several Higgs boson and beyond-Standard-Model physics analyses. The results highlight issues with modeling of additional hadronic activity in the flavor-inclusive selection, and a distinction between flavor-number schemes in the $b$-tagged phase space.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Linear polarization–direction correlations in $\gamma $-ray scattering experiments

Scattering measurements with incident linearly polarized γ rays provide information on spins, parities, and γ-ray multipolarity mixing coefficients, and, therefore, on the nuclear matrix elements involved in the transitions. Here, we present the general formalism for analyzing the observed angular correlations. The expressions are used to compute three-dimensional radiation patterns, which are important tools for optimizing experimental setups. Frequently, γ-ray transitions can proceed via two multipolarities that mix coherently. In such cases, the relative phases of the nuclear matrix elements are important when comparing results from different measurements. We discuss different phase conventions that have been used in the literature and present their relationships. Finally, we propose a basic experimental geometry consisting of detectors located at four different spatial locations. For this geometry, we present the measured anisotropies of the emitted γ rays in graphical format as an aid in the data analysis.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Radiological Scouting, Monitoring and Inspection Using Drones

Human populations and natural ecosystems are bound to be exposed to ionizing radiation from the deposition of artificial radionuclides resulting from nuclear accidents, nuclear devices or radiological dispersive devices (“dirty bombs”). On the other hand, Naturally Occurring Radioactive Material industries such as phosphate production or uranium mining, contribute to the on site storage of residuals with enhanced concentrations of natural radionuclides. Therefore, in the context of the European agreements concerning nuclear energy, namely the European Atomic Energy Community Treaty, monitoring is an essential feature of the environmental radiological surveillance. In this work, we obtain 3D maps from outdoor scenarios, and complete such maps with measured radiation levels and with its radionuclide signature. In such scenarios, we face challenges such as unknown and rough terrain, limited number of sampled locations and the need for different sensors and therefore different tasks. We propose a radiological solution for scouting, monitoring and inspecting an area of interest, using a fleet of drones and a controlling ground station. First, we scout an area with a Light Detection and Ranging sensor onboard a drone to accurately 3D-map the area. Then, we monitor that area with a Geiger–Müller Counter at a low-vertical distance from the ground to produce a radiological (heat)map that is overlaid on the 3D map of the scenario. Next, we identify the hotspots of radiation, and inspect them in detail using a drone by landing on them, to reveal its radionuclide signature using a Cadmium–Zinc–Telluride detector. We present the algorithms used to implement such tasks both at the ground station and on the drones. The three mission phases were validated using actual experiments in three different outdoor scenarios. We conclude that drones can not only perform the mission efficiently, but in general they are faster and as reliable as personnel on the ground.

Pinto, Luís Ramos (ORCID:0000000319975484)↗
NASA NTRS1991

Open-loop frequency acquisition for suppressed-carrier biphase signals using one-pole arm filters

Open loop frequency acquisition performance is discussed for suppressed carrier binary phase shift keyed signals in terms of the probability of detecting the carrier frequency offset when the arms of the Costas loop detector have one pole filters. The approach, which does not require symbol timing, uses fast Fourier transforms (FFTs) to detect the carrier frequency offset. The detection probability, which depends on both the 3 dB arm filter bandwidth and the received symbol signal to noise ratio, is derived and is shown to be independent of symbol timing. It is shown that the performance of this technique is slightly better that other open loop acquisition techniques which use integrators in the arms and whose detection performance varies with symbol timing.

Shah, B.↗