This dissertation discusses several recently developed experimental techniques for controlling the motion of neutral atoms. While laser cooling and evaporative cooling have been extremely successful and have been in widespread use for many years, these techniques are only applicable to a few atomic species. Supersonic beams provide a general method of producing cold atoms in the co-moving frame, but their speeds are typically several hundreds of meters per second in the lab frame. Methods to slow and control atoms cooled by supersonic expansion are detailed. A method for controlling the velocity of a cold beam of ground state helium using specular reflection from single crystal surfaces is demonstrated. The velocity of the beam is shown to be continuously tunable, and beam velocities as slow as 265m/s are created from an initial beam speed of 511 m/s. Magnetism is a nearly universal atomic phenomenon, making magnetic control of atomic motion a very general technique. Magnetic stopping of supersonic beams of metastable neon and molecular oxygen is demonstrated using a series of pulsed electromagnetic coils. Neon is slowed from 446 m/s to 56 m/s, and oxygen is slowed from 389 m/s to 83 m/s, removing over 95% of the kinetic energy. The experimental technique is described in detail, and the theory and principle are discussed. An experiment for slowing and trapping of atomic hydrogen isotopes at around 100 mK using a room temperature apparatus is described. A method for further cooling of magnetically trapped hydrogen ensembles, single-photon cooling, is proposed. / text

Orientador: Prof. Dr. Marcelo Bender Perotoni / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2017. / Nos últimos anos, estudos e pesquisas relacionados à substituição de armas convencionais que tem como princípio de funcionamento a combustão da pólvora ou de outros produtos químicos explosivos vem se tornando mais frequente. Nesse contexto as armas eletromagnéticas ganham destaque, visto que se utilizam da eletricidade como fonte de energia e o eletromagnetismo como princípio para lançamento de projéteis em velocidades muito mais elevadas do que aquelas alcançadas normalmente via explosivos. Este trabalho descreve a teoria, a construção e modelagem de um protótipo de pequenas dimensões de um coilgun ¿ propulsor eletromagnético que dispara um projétil metálico ferromagnético, cuja operação se assemelha aos motores elétricos lineares, que acionam fechaduras magnéticas e atuadores. O projeto apresenta baixo custo, envolve construção com elementos que podem ser facilmente encontrados, contudo, envolve conceitos relativamente sofisticados de eletromagnetismo. São discutidos os modelos de circuito do coilgun, análise da força magnética exercida no projétil e representações gráficas dos campos produzidos a partir de um simulador eletromagnético via software. A instrumentação usada para medida da velocidade do projétil também é apresentada, com dados de medições. Por fim, como principal objetivo do trabalho, é proposta uma solução inovadora ao problema da desaceleração do projétil no interior do coilgun, sendo implementado um circuito eletrônico com corte do pulso de corrente, o qual permite melhores índices de eficiência. / Recent investigations have been focused on the substitution of conventional powder-based weapons. In this context electromagnetic weapons get prominence, which use electricity as the energy source and electromagnetism as launching principle for projectiles at much higher speeds than those normally achieved via explosives, resulting, among other benefits in a much lower explosion risks. This work describes the theory and prototyping of a small-size coilgun ¿ an electromagnetic propellant device that shots a metal projectile whose operation is similar to the linear electric motors that usually drive magnetic locks and actuators. This project has low cost, it is based on easily available parts, nevertheless, relies on sophisticated concepts of electromagnetism. In this work, proper coilgun circuit models are presented, as well as the analysis of the exerted magnetic force on the projectile with images of the electromagnetic fields provided by an electromagnetic simulator via software. Instrumentation for the muzzle velocity is also presented, along with all the measurement data. Lastly, as the main objective of this work, it is proposed a novel solution to the coilgun velocity optimization by switching off the current, which allows improved efficiency levels of the device.

This master thesis focuses on literature research of problematics linked to power actuators working on electromagnetic principle to accelerate metal projectiles. It’s goal is mathematical analysis and constuction of selected type of electromagntic power actuator – induction coilgun

This master thesis focuses on literature research of problematics linked to power actuators working on electromagnetic principle to accelerate metal projectiles. It’s goal is mathematical analysis and constuction of selected type of electromagntic power actuator – induction coilgun