Author: G. W. HartPublisher:
ISBN:
Category :
Languages : en
Pages : 10
Book Description
A Study of the Effects of Photon Statistics on Thomson Scattering Data
Author: G. W. HartStudy of the Effects of Photon Statistics on Thomson Scattering Data
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
A computer code has been developed which simulates the counting statistics of a Thomson scattering measurement. The scattered and background signals in each of the wavelength channels are assumed to obey Poisson statistics, and the spectral data are fitted to a Gaussian curve using a nonlinear least-squares fitting algorithm. This method should be applicable to Thomson scattering measurements in which the signal-to-noise ratio is low due to low signal or high background. Thomson scattering data from the S-1 Spheromak have been compared to this simulation, and they have been found to be in good agreement. This code has proved to be useful assessing the effects of counting statistics relative to shot-to-shot variability in producing the observed spread in the data. It was also useful for designing improvements for the S-1 Thomson scattering system, and this method would be applicable to any measurements affected by counting statistics. 5 refs., 1 fig.
Study of the Effects of Photoelectron Statistics on Thomson Scattering Data
Author: G. W. HartPublisher:
ISBN:
Category : Thomson scattering
Languages : en
Pages : 3
Book Description
Energy Research Abstracts
Author: Fusion Energy Update
Author: Photon Counting Spectroscopy as Done with a Thomson Scattering Diagnostic
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 48
Book Description
The measurement and reduction of photon counting spectral data is demonstrated within the context of a Thomson scattering diagnostic. This diagnostic contains a microchannel plate (MCP) photomultiplier tube (PMT) as the photon sensing device. The MCP PMT is not an ideal photon sensor, the loss of photoelectrons at the MCP input and the broad charge pulse distribution at the output add to the uncertainty in recorded data. Computer simulations are used to demonstrate an approach to quantification of this added uncertainty and to develop an understanding of its source; the methodology may be applicable to the development of an understanding of photon detectors other than an MCP PMT. Emphasis is placed on the Poisson statistical character of the data, because the assumption that a Gaussian probability distribution is a reasonable statistical description of photon counting data is often questionable. When the count rate is low, the product the possible number of photon counts and the probability of measurement of a single photon is usually not sufficiently large to justify Gaussian statistics. Rather, because probabilities of measurement are so low, the Poisson probability distribution best quantifies the inherent statistical fluctuations in such counting measurements. The method of maximum likelihood is applied to derive the Poisson statistics equivalent of {sub X}2. A Poisson statistics based data fitting code is implemented using the Newton-Raphson method of multi-dimensional root finding; we also demonstrate an algorithm to estimate the uncertainties in derived quantities.
Physics Briefs
Author: An Energy Confinement Study of the MST Reversed Field Pinch Using a Thomson Scattering Diagnostic
Author: Daniel John Den HartogPublisher:
ISBN:
Category :
Languages : en
Pages : 590
Book Description
Author: 
Author: