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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 1,153 records · Page 64
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Collapse to the Center and Ambiguity in the Asymptotic Behavior of the Off-Shell Scattering Amplitude in Singular Three-Body Problems

Some examples of equations for the there-body problem where there is an oscillating high-momentum behavior are discussed. Specifically, these are (i) the equation in the fixed-center approximation; (ii) the unitarized equation in the fixed-center approximation; (iii) the Skornyakov–Ter-Martirosyan equation; and (iv) equations involving operators that are used in effective field theory—that is, those that are expandable in positive-power series in momentum. It is shown that, in such problems, there arises a situation analogous to a collapse to the center—that is, an infinite number of bound states. The energy of these states is unbounded from below. In this sense, the situation in the models being considered is close to a collapse to the center in the two-body problem.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

Waveform dependence on signal amplitude in the RHIC H-Jet polarimeter

A simulation of the signal waveform in the H-Jet polarimeter is discussed. The simulation includes a model of charge collection in the silicon detector and a response functions of the H-Jet front end electronics. Results of the simulation are compared with experimental data. It is shown that an analysis of the signal shape may help to suppress background in the H-Jet polarization measurements.

43 PARTICLE ACCELERATORS↗
NASA NTRS2004

Phase-Noise and Amplitude-Noise Measurement of Low-Power Signals

Measuring the phase fluctuation between a pair of low-power microwave signals, the signals must be amplified before detection. In such cases the phase noise of the amplifier pair is the main cause of 1/f background noise of the instrument. this article proposes a scheme that makes amplification possible while rejecting the close in 1/f (flicker) noise of the two amplifiers. Noise rejection, which relies upon the understanding of the amplifier noise mechanism does not require averaging. Therefore, our scheme can also be the detector of a closed loop noise reduction system. the first prototype, compared to a traditional saturated mixer system under the same condition, show a 24 dB noise reduction of the 1/f region.

phase noise↗