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At least 361 records · Page 20

Neutrino Induced Charged Current Coherent Pion Production for Constraining the Muon Neutrino Flux at DUNE

We study neutrino induced charge current coherent pion production (νμ CC-Coh π) as a tool for constraining the neutrino flux at the Deep Underground Neutrino Experiment (DUNE). The neutrino energy and flavor in the process can be directly reconstructed from the outgoing particles, making it especially useful to specifically constrain the muon neutrino component of the total flux. The cross section of this process can be obtained using the Adler relation with the π-Ar elastic scattering cross section, taken either from external data or, as we explore, from a simultaneous measurement in the DUNE near detector. We develop a procedure that leverages νμ CC-Coh π events to fit for the neutrino flux while simultaneously accounting for relevant effects in the cross section. We project that this method has the statistical power to constrain the uncertainty on the normalization of the flux at its peak to a few percent. This study demonstrates the potential utility of aνμ CC-Coh π flux constraint, though further work will be needed to determine the range of validity and precision of the Adler relation upon which it relies, as well as to measure the π-Ar elastic scattering cross section to the requisite precision. We discuss the experimental and phenomenological developments necessary to unlock the νμ CC-Coh π process as a "standard candle'' for neutrino experiments.

Putnam, Gray [Fermilab]↗

Fast-, Light-Cured Scintillating Plastic for 3D-Printing Applications

Additive manufacturing techniques enable a wide range of possibilities for novel radiation detectors spanning simple to highly complex geometries, multi-material composites, and metamaterials that are either impossible or cost prohibitive to produce using conventional methods. The present work identifies a set of promising formulations of photocurable scintillator resins capable of neutron-gamma pulse shape discrimination (PSD) to support the additive manufacturing of fast neutron detectors. The development of these resins utilizes a step-by-step, trial-and-error approach to identify different monomer and cross-linker combinations that meet the requirements for 3D printing followed by a 2-level factorial parameter study to optimize the radiation detection performance, including light yield, PSD, optical clarity, and hardness. The formulations resulted in hard, clear, PSD-capable plastic scintillators that were cured solid within 10 s using 405 nm light. The best-performing scintillator produced a light yield 83% of EJ-276 and a PSD figure of merit equaling 1.28 at 450–550 keVee.

Frandsen, Brian G. (ORCID:0000000319964320)↗

Gamma-ray fluxes

The design and development of detectors to analyze gamma rays greater than 20 MeV are reported. Efforts were made to identify and verify the existence of galactic gamma radiation from the galactic disc, provide information on its spectral and spatial distribution, and determine the source of gamma ray emission from the galactic plane in the direction of the galactic center. Results verify the existence of gamma radiation from the galactic disc, indicate that limits are placed on the angular width of observed line intensity, and indicate a probable flattening of the energy below 100 MeV.

Kniffen, D. A.↗

Apollo light flash investigations

The visual phenomenon of light flashes resulting from high energy, heavy cosmic rays penetrating the command module structure and crewmembers' eyes is investigated. Light flash events observed during dedicated sessions on Apollo 15, 16, 17 are described along with a Monte Carlo simulation of the exposure of an astronaut to cosmic radiation during a mission. Results of the Apollo Light Flash Moving Emulsion Detector experiment developed for Apollo 16 and 17 to obtain a direct record of incident cosmic ray particles are correlated with crewmembers' reports of light flashes.

W. Zachary Osborne↗

A large cooled infrared telescope facility for Spacelab

An optimized cooled IR telescope of 1 m aperture diameter will offer sensitivities over the 1 micron to 1 mm spectrum at least 1000 times greater than can be achieved from the ground in the atmospheric windows, and comparable sensitivities at wavelengths that are outside the windows. A study has shown that a cryogenically-cooled telescope of up to 1.6 m aperture diameter for Spacelab is feasible without new technology, although some development of detectors and scientific instruments to take advantage of the extreme sensitivity is indicated.-

Mccarthy, S. G.↗

Self-scanned anode array with a microchannel plate electron multiplier - The SSANACON

A photoelectron counting detector utilizing a 128-element linear self-scanned anode array to collect the output of a dual microchannel plate electron multiplier is described. The operation of the detector, its spatial resolution and detection efficiency, and radiation behavior are discussed. The low-noise detector was developed for the Mariner Jupiter/Saturn mission UV spectrometer, and offers a large dynamic range and count rate of 0.003 per anode-sec. It can measure simultaneously two spatially separated signals differing by more than six orders of magnitude in count rate.

Broadfoot, A. L.↗

Application of a flight-line disk crack detector to a small engine

A disk crack detector was developed and applied to a small military engine for use as a flight-line turbine crack monitor. The system consists of an eddy current type sensor and its cables within the engine, external connecting cables, and a remotely located electrical capacitance-conductance bridge and signal analyzer. As the turbine spins, the rotor is monitored by the sensor for radial surface cracks emanating from the interblade region of the rotor.

Barranger, J. P.↗

A quantitative study of the orientation bias of some edge detector schemes

The article discusses the orientational biases of various edge detection methods. On the basis of ERTS satellite images, three methods are compared: (1) Heuckel's local visual operator (1973), (2) Macleod's Gaussian edge mask detector (1972), and (3) Rosenfeld's local difference calculations (1971). The results yielded by these techniques are compared to the method for quantifying edge detector performance developed by Herskovits (1970).

Deutsch, E. S.↗

Sensor/actuator failure detection for turbofan engines

A procedure for sensor/actuator failure detection using a generalized likelihood ratio (GLR) test is described. The GLR concept can provide a reliable evaluation of failure occurence when associated with a feedback control design which does not require sensor outputs to provide data estimates. A GLR detector was developed and tested.

Behbehani, K.↗

Gasification of carbon fiber composites for the alleviation of electrical hazards

A mixture of calcium acetate and lithium acetate applied to the surface of carbon fibers caused the fibers to gasify in a simulated airplane-crash fire. Tests conducted with a JPL-developed electrical detector showed the catalyst-modified composites to release few fibers during burning, while state-of-the-art composites released several hundred. Mechanical property tests demonstrated nearly identical behavior of catalyst-modified and state-of-the-art composites. Aging tests also showed little difference in the composite strength except for a severe reduction when soaked in water. Several promising new concepts resulted from the project, including catalytic elimination of carbon particulates from diesel exhaust, catalytic improvement of coal combustion, and electrical destruction of carbon particulates in combustion systems.

Hull, G.↗

Self-heated thermocouples for far-infrared detection

A novel self-heated Bi-Sb thermocouple for far-infrared detection has been developed. The detector is suitable for integration with monolithic antennas and imaging arrays. The device is fabricated in a single photolithography masking step using a photoresist-bridge technique. This bridge technique has also been used to make microbolometers with lower 1/f noise than those made by two conventional masking steps. The thermocouples have a noise equivalent power of 7 x 10 to the -10th W/sq rt of Hz and a 3-dB frequency response of 150 kHz.

Neikirk, D. P.↗

Observational evidence for solar wind acceleration at the base of coronal holes

An EUV spectrometer with a microchannel plate detector was developed to measure Doppler shifts of coronal and transition region lines. The results of three sounding rocket fights of this instrument indicate that EUV resonance emission lines are systematically shifted toward shorter wavelength within coronal holes. This "blue-shift" signature, first identified within compact low latitude holes, was also observed in a well developed polar coronal hole. The maximum measured shift within these coronal holes corresponds to a velocity relative to the remaining solar disc of 12 km/s in lambda 625 Mg X T to the approximately 10 to the 6.15 K power and 7 km /s/ in lambda 629 OV (T to the approximately 10 to the 5.4 K power). The existing data indicate that these blue-shifts are a common (and possibly universal) signature of coronal holes. These data provide important information on the acceleration of coronal plasma in open magnetic field regions, although the interpretation of observed Doppler shifts to derive a systematic mass flux is to some extent model dependent. A straightforward hypothesis is that the blueshift signature is a direct manifestation of the high speed solar wind deep within the transition region and inner corona.

Rottman, G. J.↗

Application of photodiodes to the detection of electromagnetic bursts

A new type of photodiode + scintillator (1 m2 x 1 cm) detector is developed to detect the large electro-magnetic burst under an EX-chamber. The threshold burst size is found to be 4.3 x 10 the 5 particles at the center of the scintillator. Therefore a gamma-ray family of 10 TeV is detectable by it, when it is set under 14 r.1. of iron. In addition, a very fast (2.4 nsec width) and very bright (correspond to 10 to the 6 particles) scintillation pulse has become avarable for this study.

Fukushima, Y.↗

Nd:YAG and ruby based lidar systems for remote sensing of atmospheric aerosols

The application of solid-state lasers to the study of stratospheric and tropospheric aerosols is analyzed. A 48-inch mobile lidar which operates in the 0.6943, 1.06, 0.3472, and 0.5300 micron ranges is utilized to monitor the stratosphere. The detectors of the system consist of photomultipliers, and the dual-channel, computer-based data-acquisition-system which provides on-line plotting of scattering ratio profiles. The components of the 14-inch aperture, dual-wavelength airborne lidar system that operates with ruby and Nd:YAG transmitters are described. An 8-inch, down-looking airborne lidar with silicon diode or photomultiplier detectors was developed. The capabilities of the system alone and when combined with the 14-inch lidar are discussed. Examples of the data provided by the three lidar systems are presented, revealing the reliability and operational efficiency of the systems.

Fuller, W. H., Jr.↗

Self-Aligned Guard Rings For Schottky-Barrier Diodes

Proposed self-aligned guard ring increases active area of Schottky-barrier infrared detector. Concept developed for silicide Schottky-barrier diodes in which platinum silicide or iridium silicide Schottky-contacts provide cutoff wavelengths of about 6 or 10 micrometers. Grid of silicon dioxide doped with phosphorus etched on silicon wafer, and phosphorus from grid diffused into substrate, creating n-type guard rings. Silicide layers formed in open areas of grid. Overlap of guard rings and silicide layers small.

Lin, True-Lon↗

Microcontrollers Generate Timing Signals For CCD Arrays

Microcontrollers generate timing signals for charge-coupled-device array detectors in electronic system developed to test such detectors. With microcontroller, one changes timing signals via software, without changes in wiring. Approach more flexible, timing signals changed easier and quicker.

Hostetter, Marilyn K.↗

Solar maximum mission/ultraviolet spectrometer and polarimeter studies

This final report for NASA Contract No. NAS8-35921 describes various studies performed for the Ultraviolet Spectrometer and Polarimeter (UVSP) experiment, one of several instruments on the Solar Maximum Mission (SMM) satellite which was launched on 14 February 1980. The UVSP consisted primarily of a Gregorian telescope and an Ebert-Fastie spectrometer with a polarimeter that could be inserted into the light path. The spacecraft and most of the instruments, including the UVSP, operated successfully until 23 November 1980, when part of the SMM attitude control system (fine pointing control) failed. The UVSP was then unable to observe the Sun until 18 April 1984, when the SMM was visited by the space shuttle and the attitude control module was replaced by astronauts. The SMM mission ended when the spacecraft reentered the atmosphere of the Earth and was thereby destroyed on 2 December 1989. The topics covered in this report include the following: (1) ultraviolet stellar polarimetry (probably the first such attempted measurement); no polarization as detected and the upper limits, based on the sensitivity as determined by the observed count rate, are rather high; (2) an investigation into the possible position of the UVSP wavelength drive after it became stuck on 26 April 1985; (3) fast timing tests for sit-and-state observations involving one or two detectors; (4) development of computer subroutines to allow the calculation of the component of the SMM spacecraft orbital velocity along the line of sight to the Sun at any desired time during the 1984/1985 period when the UVSP wavelength drive was operating properly; (5) listing of published research papers; (6) description of the UVSP catalog of observations; and (7) description of UVSP calibration report and data users guide.

Henze, William, Jr.↗