O PROGRAMA DE PÓS-GRADUAÇÃO EM FÍSICA convida para o seminário:
Virtual-Slit Focusing in a Cycloidal Mass Spectrometer – A Proof of Concept*
Dr. Rafael Bento Serpa
Postdoctoral Associate | Duke University Nanomaterials and Thin Films Lab
*Evento de presença obrigatória da disciplina seminários
Resumo:
This work demonstrates a novel approach to mass spectrometry using the “virtual-slit” created by the small, spatial volume from which ions are generated by localized ionization techniques (e.g., laser ionization of particles and surfaces, and spark ionization). That is, the volume in which the ions are generated creates a localized source of ions in much the same way as a slit that allows only ions from a specific cross-sectional area to pass. As demonstrated in this work, the unique perfect focusing properties of a cycloidal mass analyzer can enable the localized ionization volume to function as a virtual slit. In this manuscript, we provide a proof-of-concept (POC) demonstration of a virtual-slit cycloidal mass spectrometer (VS-CyMaS) consisting of a cycloidal mass analyzer, a laser ionization source, and an ion array detector. The laser is used to ionize either bulk or thin-film samples of Cu, Ti, Ni, and Cr. Results indicate that the width of the peaks at the detector is the same as the laser spot size, validating the concept of virtual-slit focusing. Furthermore, the material ablated with each laser pulse for Ti and Cu is estimated at 60 and 140 fg, respectively, indicating that a very low detection limit is possible given the ability of the cycloidal mass analyzer to collect ions generated by laser ionization that have wide energy and angular dispersions.
Data: 29 de outubro de 2021 – (sexta-feira) – Horário: 10h15min
Link de acesso ao canal do programa no youtube: https://youtu.be/t75RNYAdy1s
Defesa de Tese*
Everton Botan
IDENTIFICAÇÃO DE ESTRELAS VARIÁVEIS NO VVV E INVESTIGAÇÃO DE ESTRUTURAS NO BOJO GALÁCTICO
*(evento de reposição da disciplina seminários)
Banca Examinadora:
Prof. Dr. Roberto Kalbusch Saito – (presidente) – UFSC
Prof. Dr. Jacques Raymond Daniel Lepine – (membro externo) – IAG/USP
Prof. Dr. Helio Jaques Rocha-Pinto – (membro externo) – Observatório do Valongo – UFRJ
Prof. Dr. Daniel Ruschel Dutra – (membro titular) – UFSC/FSC
Prof. Dr. Antônio Nemer Kanaan Neto – (membro titular) – UFSC/FSC
Data: 29 de outubro de 2021 – sexta-feira – Horário: 9h30min – Local: vídeoconferência
Link de acesso a sala virtual: https://meet.google.com/dof-hsws-ezf
O PROGRAMA DE PÓS-GRADUAÇÃO EM FÍSICA convida para o seminário:
Aberration and Doppler effect on the CMB: kinematical and intrinsic contributions*
Dr. Omar Roldán
Pós-doutorando – UFRJ
*Evento de presença obrigatória da disciplina seminários
Resumo:
The aberration and Doppler coupling effects of the Cosmic Microwave Background (CMB) were measured by the Planck satellite. The most straightforward interpretation leads to a direct detection of our peculiar velocity, consistent with the measurement of the well-known dipole. We show however, that in some cases a primordial dipolar potential can also produce such effects. But in addition it produces other signatures due to integrated terms which we will discuss in some detail. We also discuss how aberration measurements can be used to constraint some models which introduce super-horizon perturbations to explain the hemispherical asymmetry. This work has also been used to infer the Intrinsic Dipole. Finally we also discuss about CMB anisotropies at all orders and the non-linear Sachs-Wolfe formula.
Most of the seminar is based on the paper:
https://arxiv.org/abs/1603.02664
https://arxiv.org/abs/1706.08428
Other References:
https://arxiv.org/abs/1708.00441
https://arxiv.org/abs/2011.08385
Data: 22 de outubro de 2021 – (sexta-feira) – Horário: 10h15min
Link de acesso ao canal do programa no youtube: https://youtu.be/sqea8-jX35Q
