First Full Six-Dimensional Phase Space Measurement of a Hadron Beam

A significant limitation for accelerator physics simulation tools is the inability to accurately predict the distribution of particles in a linear accelerator hadron beam. Even state-of-the-art particle-in-cell codes that contain all the relevant physics are only able to reproduce the beam\u27s measured root-mean-square (RMS) parameters. However, characterizing the beam at several standard deviations beyond RMS is necessary to predict beam loss, one of the limiting factors for achievable beam power and performance in high power, high intensity accelerators. The accelerator community agrees that the discrepancy between measurement and simulation stems from a poor understanding of the initial particle phase space distribution entering the linac. This can be credited to the fact that no complete six dimensional measurement of the initial beam distribution entering a linac has ever been accomplished.This dissertation presents the first complete six-dimensional phase space measurement of a particle beam in a hadron accelerator [1]. The measurement was completed at Spallation Neutron Source Beam Test Facility, a functional duplicate of the SNS front-end capable of producing a pulsed 2.5 MeV H- ion beam. The technique coordinated six movable slits to isolate small, specified volumes systematically over the full six-dimensional phase space and measure the charge inside each volume. The measurement revealed previously unknown, intensity dependent correlations in the phase space distribution that are not visible in lower dimensional measurements. Results will also serve as a full and accurate particle distribution for bench-marking simulations and predicting beam dynamics at the level which relates to beam loss

First Results of the IOTA Ring Research at Fermilab

The IOTA ring at Fermilab is a unique machine exclusively dedicated to accelerator beam physics R&D. The research conducted at IOTA includes topics such as nonlinear integrable optics, suppression of coherent beam instabilities, optical stochastic cooling and quantum science experiments. In this talk we report on the first results of experiments with implementations of nonlinear integrable beam optics. The first of its kind practical realization of a two-dimensional integrable system in a strongly-focusing storage ring was demonstrated allowing among other things for stable beam circulation near or at the integer resonance. Also presented will be the highlights of the world’s first demonstration of optical stochastic beam cooling and other selected results of IOTA’s broad experimental program

The ChatGPT artificial intelligence chatbot: How well does it answer accounting assessment questions?

ChatGPT, a language-learning model chatbot, has garnered considerable attention for its ability to respond to users’ questions. Using data from 14 countries and 186 institutions, we compare ChatGPT and student performance for 28,085 questions from accounting assessments and textbook test banks. As of January 2023, ChatGPT provides correct answers for 56.5 percent of questions and partially correct answers for an additional 9.4 percent of questions. When considering point values for questions, students significantly outperform ChatGPT with a 76.7 percent average on assessments compared to 47.5 percent for ChatGPT if no partial credit is awarded and 56.5 percent if partial credit is awarded. Still, ChatGPT performs better than the student average for 15.8 percent of assessments when we include partial credit. We provide evidence of how ChatGPT performs on different question types, accounting topics, class levels, open/closed assessments, and test bank questions. We also discuss implications for accounting education and research