Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “PHASE DETECTOR”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,135 records · Page 63
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Development of a tagged source of Pb-206 nuclei

There is a particular class of unavoidable backgrounds that plague low-background experiments and rare event searches, particularly those searching for nuclear recoil event signatures: decaying daughters of the 238 U nuclear decay chain, which result from radon plate-out on detector materials. One such daughter isotope, 210 Po, undergoes α-decay and produces a recoiling 103 keV 206 Pb nucleus. In this study, to characterize this important background in the context of noble element detectors, we have implemented a triggered source for these 206 Pb recoils in a dual-phase xenon time projection chamber (Xe TPC) within the Davis Xenon R&D testbed system (DAX). By adhering 210 Po to the surface of a PIN diode and electrically floating the diode on the cathode of the TPC, we tag the α signals produced in the PIN diode and trigger on the correlated nuclear recoils in the liquid xenon (LXe). Lastly, we discuss our methods for 210 Po deposition, electronic readout of the PIN diode signals at high voltage, and analysis methods for event selection.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

Monte Carlo simulations of trapped ultracold neutrons in the UCN τ experiment

We report that in the UCNτ experiment, ultracold neutrons (UCN) are confined by magnetic fields and the Earth's gravitational field. Field-trapping mitigates the problem of UCN loss on material surfaces, which caused the largest correction in prior neutron experiments using material bottles. However, the neutron dynamics in field traps differ qualitatively from those in material bottles. In the latter case, neutrons bounce off material surfaces with significant diffusivity and the population quickly reaches a static spatial distribution with a density gradient induced by the gravitational potential. In contrast, the field-confined UCN—whose dynamics can be described by Hamiltonian mechanics—do not exhibit the stochastic behaviors typical of an ideal gas model as observed in material bottles. In this report, we will describe our efforts to simulate UCN trapping in the UCNτ magnetogravitational trap. We compare the simulation output to the experimental results to determine the parameters of the neutron detector and the input neutron distribution. The tuned model is then used to understand the phase-space evolution of neutrons observed in the UCNτ experiment. Lastly, we will discuss the implications of chaotic dynamics on controlling the systematic effects, such as spectral cleaning and microphonic heating, for a successful UCN lifetime experiment to reach a 0.01% level of precision.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

Measurement of C P Violation Observables in D + → K − K + π + Decays

A search for violation of the charge-parity ( C P ) symmetry in the D + → K − K + π + decay is presented, with proton-proton collision data corresponding to an integrated luminosity of 5.4 fb − 1 , collected at a center-of-mass energy of 13 TeV with the LHCb detector. A novel model-independent technique is used to compare the D + and D − phase-space distributions, with instrumental asymmetries subtracted using the D s + → K − K + π + decay as a control channel. The p value for the hypothesis of C P conservation is 8.1%. The C P asymmetry observables A C P | S ϕ π + = ( 0.95 ± 0.4 3 stat ± 0.2 6 syst ) × 10 − 3 and A C P | S K ¯ * 0 K + = ( − 0.26 ± 0.5 6 stat ± 0.1 8 syst ) × 10 − 3 are also measured. These results show no evidence of C P violation and represent the most sensitive search performed through the phase space of a multibody decay. © 2024 CERN, for the LHCb Collaboration 2024 CERN

Aaij, R. (ORCID:0000000305331952)↗
DOE OSTI2015

Report of improved performance in Talbot–Lau phase-contrast computed tomography

Purpose: Many expectations have been raised since the use of conventional x-ray tubes on grating-based x-ray phase-contrast imaging. Despite a reported increase in contrast-to-noise ratio (CNR) in many publications, there is doubt on whether phase-contrast computed tomography (CT) is advantageous in clinical CT scanners in vivo. The aim of this paper is to contribute to this discussion by analyzing the performance of a phase-contrast CT laboratory setup. Methods: A phase-contrast CT performance analysis was done. Projection images of a phantom were recorded, and image slices were reconstructed using standard filtered back projection methods. The resulting image slices were analyzed by determining the CNRs in the attenuation and phase image. These results were compared to analytically calculated expectations according to the already published phase-contrast CT performance analysis by Raupach and Flohr [Med. Phys. 39, 4761–4774 (2012)]. There, a severe mistake was found leading to wrong predictions of the performance of phase-contrast CT. The error was corrected and with the new formulae, the experimentally obtained results matched the analytical calculations. Results: The squared ratios of the phase-contrast CNR and the attenuation CNR obtained in the authors’ experiment are five- to ten-fold higher than predicted by Raupach and Flohr [Med. Phys. 39, 4761–4774 (2012)]. The effective lateral spatial coherence length deduced outnumbers the already optimistic assumption of Raupach and Flohr [Med. Phys. 39, 4761–4774 (2012)] by a factor of 3. Conclusions: The authors’ results indicate that the assumptions made in former performance analyses are pessimistic. The break-even point, when phase-contrast CT outperforms attenuation CT, is within reach even with realistic, nonperfect gratings. Further improvements to state-of-the-art clinical CT scanners, like increasing the spatial resolution, could change the balance in favor of phase-contrast computed tomography even more. This could be done by, e.g., quantum-counting pixel detectors with four-fold smaller pixel pitches.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2020

Holotomography Phase-Retrieval

Holotomography is a non-destructive x-ray imaging technique which allows to visualize the interior morphology of object without damaging them. It is similar to x-ray computed tomography (CT), but unlike conventional CT, which is based on the attenuation of x-rays passing through the object, holotomography exploits the phase shift caused by the sample. This phase-contrast imaging allows to increase image contrast by recovering refractive index of materials and is proven to be more sensitive to density variations than conventional absorption-based X-ray imaging when applied to low-Z materials. In holotomography, the phase is retrieved by measuring the variations in intensity of the object at different sample to detector distances. Several algorithms exist to perform this task such as, contrast transfer function (CTF), transport of intensity equation (TIE), and a mixed approach which combine both TIE and CTF.

Forien, Jean-Baptiste↗
DOE OSTI2018

Muon Beam Dynamics and Spin Dynamics in the g-2 Storage Ring

The goal of the new g-2 experiment at fermilab is a measurement of the anomalous magnetic moment of the muon, with uncertainty of less than 140 ppb. The experimental method is to store a beam of polarized muons in a storage ring with pure vertical dipole field and electrostatic focusing, and to measure the precession frequency. Control of the systematics depends on unprecedented knowledge of the details of the phase space of the muon distribution. That knowledge is derived from direct measurements with scintillating fiber detectors that are inserted into the muon beam for diagnostic measurements, traceback straw tube tracking chambers, as well as the calorimeters that measure energy, time and position of the decay positrons. The interpretation of the measurements depends on a detailed model of the storage ring guide field. This invited talk presents results of studies of the distribution from the commissioning run of the experiment.

43 PARTICLE ACCELERATORS↗
DOE OSTI2018

Design and Test of the Mu2e Undoped CsI + SiPM Crystal Calorimete

The talk focused on the Charged Lepton Flavor Violation (CLFV) part of the Mu2e project, including an introduction of the concept and the experimental layout and detectors. Calorimeter requirements were also discussed, including components, single channel tests, prototypes' performance, and the production phase.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

An Introduction to Radiation Damage in Minerals and Ceramics [Slides]

Radiation effects in minerals and ceramics are quite distinct from effects observed in metals. This is largely due to interactions between radiation and the electronic structure of insulating materials that are unique compared to metallic conductors. Most notably, insulators exhibit property changes when energetic particles lose energy to electrons in the solid, whereas metals are unaffected by electronic energy losses. In addition, displacive radiation damage effects (atoms being knocked off their lattice sites by energetic particles) are much more complex in insulators, due to the complexities of their crystal structures (multiple cation and anion sublattices). In this presentation, we will focus on the atomistic mechanisms responsible for radiation damage in minerals and ceramics, when energetic particles lose energy while penetrating a solid. We will consider several examples, including (i) irradiation induced color center formation in gemstones; (ii) latent defects in alkali halides (relevance to thermoluminescent detectors); (iii) radioactive decay-induced amorphization of natural minerals; and (iv) extended defect formation and phase stability in complex oxides.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Methodology of the Extraction of Multi-Differential Cross Sections of Charged-Current $\nu_\mu$-Argon Interactions in MicroBooNE Using Wire-Cell $\nu_\mu$CC Selection

Neutrino physics experiments rely on accurate nuclear-interaction models that are in part guided by experimental observations. Multi-differential cross section measurements are particularly valuable for exploring the underlying physics described in these models, making them a significant step forward in the field. This note presents methodology in preparation to unfold neutrino flux-averaged double and triple-differential cross sections of the inclusive muon neutrino charged-current interaction on Argon. This work builds upon the existing framework and methodology presented in recent energy dependent cross section measurements at MicroBooNE using the Wire-Cell tomographic event reconstruction. The signal definition, choice of binning, and handling of estimated detector uncertainties are discussed, and the MicroBooNE simulation model is validated over the multi-dimensional phase space of muon momentum, muon polar angle, and visible hadronic energy.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS1990

DS/LPI autocorrelation detection in noise plus random-tone interference

An analysis is presented of a frequency-noncoherent, two-lag autocorrelation statistic for the wideband detection of random binary phase-shift keying (BPSK) signals in noise plus random multitone interference. It is shown that this detector is quite robust to the presence or absence of interference and its specific parameter values contrary to an energy detector. The rule assumes knowledge of the data rate and the active scenario under H0. The purpose of the paper is to promote the real-time autocorrelation domain and its samples (lags) as a viable approach for detecting random signals in dense environments.

Hinedi, Sami↗
NASA NTRS1992

X ray observations of late-type stars using the ROSAT all-sky survey

The ROSAT mission made the first x ray survey of the entire sky using an imaging detector. Although ROSAT is a joint NASA/German project and involves direct American participation during its second phase of pointed observations, the all-sky survey remains the sole property of the German investigators. NASA grant represented the first use of ROSAT data analysis funds to support direct American participation in the ROSAT all-sky survey. The project involved a collaborative agreement between the Joint Institute for Laboratory Astrophysics (JILA) and the Max-Planck-Institut fur Extraterrestrische Physik (MPE) where JILA supplied MPE with a post-doctoral research associate with experience in the field of stellar (coronal) x ray emission to work within their ROSAT group. In return, members of the cool star research group at JILA were given the opportunity to collaborate on projects involving ROSAT all-sky survey data. Both sides have benefitted (and still benefit) from this arrangement since MPE suffers from a shortage of researchers who are interested in x ray emission from 'normal' stars and white dwarfs. MPE has also drawn upon experience in optical identification of x ray sources from the Einstein Extended Medium Sensitivity Survey in planning their own identification strategies for the ROSAT all-sky survey. The JILA cool stars group has benefitted since access to all-sky survey data has expanded the scope of their already extensive research programs involving multiwavelength observations of late-type stars. ROSAT was successfully launched on 1 June 1990 and conducted the bulk of the survey from 30 July 1990 to 25 January 1991. Data gaps in the survey have subsequently been made up. At the time of this writing (February 1992), the survey data have been processed once with the Standard Analysis Software System (SASS). A second processing will soon begin with improvements made to the SASS to correct errors and bugs found while carrying out scientific projects with data from the first processing. We outline the major research activities of Dr. Fleming over the past year (detailed accounts of his activities during the first two years of this grant can be found in the first-year and second-year status reports on this grant). Regarding the three specific projects which were proposed in the original proposal, two of them (White Dwarfs and Late M Dwarfs) are near completion. The results are described in two conference proceedings which are appended.

Linsky, Jeffrey L.↗
NASA NTRS1993

Plasma waves observed at low altitudes in the tenuous Venus nightside ionosphere

The Pioneer Venus (PV) Orbiter Electric Field Detector (OEFD) measured many plasma wave bursts throughout the low altitude ionosphere during the final entry phase of the spacecraft. Apart from 100 Hz bursts observed at very low altitudes (approx. 130 km), the bursts fall into two classes. The first of these is a wideband signal that is observed in regions of low magnetic field, but average densities, in comparison to the prevailing ionospheric condition. This wideband signal is not observed in the 30 kHz channel of the OEFD, but is resricted to the 5.4 kHz channel and lower. Since these bursts are observed with roughly constant burst rate above 160 km altitude, we attribute them to ion acoustic mode waves generated by precipitating solar wind electrons. The second type of signal is restricted to 100 Hz only, and is observed in the regions of low electron beta, consistent with whistler-mode waves. These waves could be generated by lightning in the Venus atmosphere if the vertical component of the magnetic field greater than 3.6 nT. Because the ionosphere is very different during the entry phase, compared to the ionosphere as observed early in the Pioneer Venus mission, any conclusions regarding the source of the plasma waves detected during entry phase cannot be applied directly to the earlier observations.

Strangeway, R. J.↗
NASA NTRS1993

Plasma Waves Observed at Low Altitudes in the Tenuous Venus Nightside Ionosphere

The Pioneer Venus Orbiter Electric Field Detector (OEFD) measured many plasma wave bursts throughout the low altitude ionosphere during the final entry phase of the spacecraft. Apart from 100 Hz bursts observed at very low altitudes (approx. 130 km), the bursts fall into two classes. The first of these is a wideband signal that is observed in regions of low magnetic field, but average densities, in comparison to the prevailing ionospheric condition. This wideband signal is not observed in the 30 kHz channel of the OEFD, but is restricted to the 5.4 kHz channel and lower. Since these bursts are observed with roughly constant burst rate above 160 km altitude, we attribute them to ion acoustic mode waves generated by precipitating solar wind electrons. The second type of signal is restricted to 100 Hz only, and is observed in regions of low electron beta, consistent with whistler-mode waves. These waves could be generated by lightning in the Venus atmosphere if the vertical component of the magnetic field greater than 3.6 nT. Unfortunately, the spacecraft spin axis is mainly horizontal, and only that component of magnetic field can be measured. Alternatively, the 100 Hz bursts could be generated locally through gradient drift instabilities, provided the ambient magnetic field is horizontal. Because the ionosphere is very different during the entry phase, compared to the ionosphere as observed early in the Pioneer Venus mission, any conclusions regarding the source of the plasma waves detected during entry phase cannot be applied directly to the earlier observations.

Strangeway, R. J.↗
NASA NTRS2007

GIFTS SM EDU Level 1B Algorithms

The Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) SensorModule (SM) Engineering Demonstration Unit (EDU) is a high resolution spectral imager designed to measure infrared (IR) radiances using a Fourier transform spectrometer (FTS). The GIFTS instrument employs three focal plane arrays (FPAs), which gather measurements across the long-wave IR (LWIR), short/mid-wave IR (SMWIR), and visible spectral bands. The raw interferogram measurements are radiometrically and spectrally calibrated to produce radiance spectra, which are further processed to obtain atmospheric profiles via retrieval algorithms. This paper describes the GIFTS SM EDU Level 1B algorithms involved in the calibration. The GIFTS Level 1B calibration procedures can be subdivided into four blocks. In the first block, the measured raw interferograms are first corrected for the detector nonlinearity distortion, followed by the complex filtering and decimation procedure. In the second block, a phase correction algorithm is applied to the filtered and decimated complex interferograms. The resulting imaginary part of the spectrum contains only the noise component of the uncorrected spectrum. Additional random noise reduction can be accomplished by applying a spectral smoothing routine to the phase-corrected spectrum. The phase correction and spectral smoothing operations are performed on a set of interferogram scans for both ambient and hot blackbody references. To continue with the calibration, we compute the spectral responsivity based on the previous results, from which, the calibrated ambient blackbody (ABB), hot blackbody (HBB), and scene spectra can be obtained. We now can estimate the noise equivalent spectral radiance (NESR) from the calibrated ABB and HBB spectra. The correction schemes that compensate for the fore-optics offsets and off-axis effects are also implemented. In the third block, we developed an efficient method of generating pixel performance assessments. In addition, a random pixel selection scheme is designed based on the pixel performance evaluation. Finally, in the fourth block, the single pixel algorithms are applied to the entire FPA.

Tian, Jialin↗
DOE OSTI2018

Light Dark Matter eXperiment (LDMX)

We present an initial design study for LDMX, the Light Dark Matter Experiment, a small-scale accelerator experiment having broad sensitivity to both direct dark matter and mediator particle production in the sub-GeV mass region. LDMX employs missing momentum and energy techniques in multi-GeV electro-nuclear fixed-target collisions to explore couplings to electrons in uncharted regions that extend down to and below levels that are motivated by direct thermal freeze-out mechanisms. LDMX would also be sensitive to a wide range of visibly and invisibly decaying dark sector particles, thereby addressing many of the science drivers highlighted in the 2017 US Cosmic Visions New Ideas in Dark Matter Community Report. LDMX would achieve the required sensitivity by leveraging existing and developing detector technologies from the CMS, HPS and Mu2e experiments. In this paper, we present our initial design concept, detailed GEANT-based studies of detector performance, signal and background processes, and a preliminary analysis approach. We demonstrate how a first phase of LDMX could expand sensitivity to a variety of light dark matter, mediator, and millicharge particles by several orders of magnitude in coupling over the broad sub-GeV mass range.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

Commissioning Trigger for the SpinQuest/E1039 Experiment

The SpinQuest experiment at Fermilab aims to measure the Sivers asymmetry for the light antiquarks in the nucleon using the Drell-Yan process. If the Sivers asymmetry is not zero, we will have found evidence for non-zero orbital angular momentum of light antiquarks. The commissioning of the SpinQuest experiment has two phases. First, we will trigger on cosmic ray muons to understand the performance of the SpinQuest detector which comprises hodoscopes, wire chambers, and proportional tubes. Second, we will use the 120 GeV Main Injector proton beam to test all the detectors more thoroughly and analyze the data to get prepared for physics running. This poster will present the structure of the commissioning trigger, the timing calibration, and the measured performance of the hodoscopes using cosmic rays.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

CdZnTeSe: Recent advances for radiation detector applications

The quest for cost-effective, high performing room temperature semiconductor detector (RTSD) materials for high energy gamma rays has been continuing for more than three decades. The requirements for RTSD materials, however, are more stringent as compared to other applications unrelated to detection of X- and gamma-rays, mainly due to the requirement of thick detectors for sufficient absorption of high-energy electromagnetic radiation and excellent charge-transport properties. The II-VI compound CdZnTe (CZT) with the composition of 10 atomic % Zn (Cd0.9Zn0.1Te) has been the material of choice over the past several years, and it has dominated the commercial market for RTSD materials and detectors. Despite its commercial success as a room temperature radiation detection material, CZT suffers from a lack of compositional homogeneity on both a micro- and macro-scale and the presence of high concentrations of sub-grain boundary (dislocation walls) networks and secondary phases (Te-rich inclusions). This chapter focuses on the presence of performance-limiting defects in CZT that hinder the yield and elevate the cost of high-quality detectors. The presence of such performance-limiting defects has restricted widespread deployment of CZT for a variety of potential applications, particularly for uses of relatively large detectors where the demands on material perfection are significantly greater. In the recent past, replacing some of the tellurium with selenium in the CZT matrix was found to be very effective in drastically reducing the Te-rich secondary phases and dislocation networks, plus

Roy, Utpal N.↗