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Thomas, M.

Publications and source records attributed to Thomas, M..

16 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Project 8 apparatus for cyclotron radiation emission spectroscopy with 83m Kr and tritium

Cyclotron Radiation Emission Spectroscopy (CRES) is a novel technique for the precise measurement of relativistic electron energy. This technique is being employed by the Project 8 collaboration for measuring a high-precision tritium beta decay spectrum to perform a frequency-based measurement of the neutrino mass. In this work, we describe the Project 8 Phase II apparatus, used for the detection of the CRES signal from the conversion electrons of 83m Kr and the first CRES measurement of the beta-decay spectrum of molecular tritium.

Neutrino detectors↗
DOE OSTI2024

Deep learning based event reconstruction for cyclotron radiation emission spectroscopy

The objective of the cyclotron radiation emission spectroscopy (CRES) technology is to build precise particle energy spectra. This is achieved by identifying the start frequencies of charged particle trajectories which, when exposed to an external magnetic field, leave semi-linear profiles (called tracks) in the time–frequency plane. Due to the need for excellent instrumental energy resolution in application, highly efficient and accurate track reconstruction methods are desired. Deep learning convolutional neural networks (CNNs) - particularly suited to deal with information-sparse data and which offer precise foreground localization—may be utilized to extract track properties from measured CRES signals (called events) with relative computational ease. In this work, we develop a novel machine learning based model which operates a CNN and a support vector machine in tandem to perform this reconstruction. A primary application of our method is shown on simulated CRES signals which mimic those of the Project 8 experiment—a novel effort to extract the unknown absolute neutrino mass value from a precise measurement of tritium β - -decay energy spectrum. When compared to a point-clustering based technique used as a baseline, we show a relative gain of 24.1% in event reconstruction efficiency and comparable performance in accuracy of track parameter reconstruction.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS2000

Radar observations and physical model of asteroid 6489 Golevka

We report 8510-MHz (3,5-cm) radar observations of the Earth crossing asteroid (ECA) 6489 Golevka (1991 JX) obtained between June 3 and June 15, 1995, at Goldstone, the Very Large Array and the Evpatoria (Ukraine) and Kashima (Japan) radio antennas.

Astroids orbits 6489 Golevka toutatis↗
NASA NTRS1999

Radar and Optical Observations of Asteroid 1998 KY26

Observations of near-Earth asteroid 1998 KY26 shortly after its discovery reveal a slightly elongated spheroid with a diameter of about 30 m, a composition analogous to carbonaceous chondritic meteorites, and a rotation period of 10.7 minutes, which is an order of magnitude shorter that that measured for any other solar system object.

radar asteroids near-Earth Asteroid 1998 KY26↗
NASA NTRS1998

Radar Observations of Asteroid 2063 Bacchus

We report Doppler-only (cw) and delay-Doppler radar observations of Bacchus obtained at Goldstone at a transmitter frequency of 8510 MHz (3.5 cm) on 1996 March 22, 24, and 29.

delay-Doppler radar observations asteroid Bacchus ↗
NASA NTRS1998

Radar Observations of Asteroid 7822 (1991 CS)

We report Doppler-only (cw) radar observations of 1991 CS obtained at Goldstone at a transmitter frequency of 8510 MHz (3.5 cm) on 1996 August 26, 27, 28, and 29.

Asteroids radar 1991 CS asteroid 7822↗
NASA NTRS1994

Static Shape Control of Inflatable Structures

Inflatable structural concepts have been proposed for numerous applications such as antennas for microwave remote sensing, space-based interferometry, solar concentrators, and for dual purposes (e.g. concentrator for power/antenna for communication). In comparison to other mechanically deployable systems, inflatable structures have significant advantages of a much lower cost, weight, and packaging volume, but higher deployment reliability and damping properties.

Inflatable structures↗
NASA NTRS1989

Advances in large inflatable reflectors

For most applications in space for which they were tried, inflatable structures show a significant weight reduction when compared to mechanical structures. Inflatables are unmatched when compared to mechanical structures when packaged volume is considered. The reliability of deployment of inflatable structures was known for years. When properly designed, such a system is inherently more reliable because it has very few points of failure. Fully inflatable vs. rigidized inflatable structures are discussed. The L'Garde solar concentrator experience is described. Reflector surface and cylinder rigidization, improvement in gore design tools, and expected advances in rigidization schemes with near future are examined.

Thomas, M.↗
NASA NTRS1983

Inflated antennas

Inflatable space antennas are discussed. A brief history of inflatable structures is given. Several antenna configurations are described. The antenna configuration consisting of a thin film cone and parabolic held to the proper shape by internal pressure is discussed in detail.

Friese, G. J.↗
NASA NTRS1983

Initial '80s Development of Inflated Antennas

State of the art technology was considered in the definition and documentation of a membrane surface suitable for use in a space reflector system for long durations in orbit. Requirements for a metal foil-plastic laminate structural element were determined and a laboratory model of a rigidized element to test for strength characteristics was constructed. Characteristics of antennas ranging from 10 meters to 1000 meters were determined. The basic antenna configuration studied consists of (1) a thin film reflector, (2) a thin film cone, (3) a self-rigidizing structural torus at the interface of the cone and reflector; and (4) an inflation system. The reflector is metallized and, when inflated, has a parabolic shape. The cone not only completes the enclosure of the inflatant, but also holds the antenna feed at its apex. The torus keeps the inflated cone-reflector from collapsing inward. Laser test equipment determined the accuracy of the inflated paraboloids.

Friese, G. J.↗
NASA NTRS1978

Chemisorption of CO on Pd particles supported on mica

A UHV technique is presented for evaluating the adsorption-desorption properties of UHV vapor-deposited metal particles supported on insulating substrates. Desorption studies of CO from particulate and continuous Pd films supported on mica were performed. The desorption results indicate that: the CO desorption energies from the deposited metals are much lower than those from bulk single crystals; two desorption states exist for the vapor-deposited films; and the lower energy desorption peak of the vapor-deposited films is coverage dependent. Possible reasons for the difference between previously reported CO desorption studies on bulk substrates and the present results are discussed.

Thomas, M.↗