@InProceedings{OliveiraAgSoMeBaMi:2020:EvQfNi,
               author = "Oliveira, Rog{\'e}rio de Moraes and Aguiar, Odylio Denys de and 
                         Souza, Renata Lopes Gon{\c{c}}alves de and Mello, Carina Barros 
                         and Baldan, Maur{\'{\i}}cio Ribeiro and Miranda, Edson Luiz de",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)}",
                title = "Evaluation of the Q-factor of niobium superconducting reentrant 
                         cavities treated by nitrogen plasma based ion implantation",
                 year = "2020",
         organization = "Encontro de Outono Sociedade Brasileira de F{\'{\i}}sica",
             abstract = "Surface treatment is a mandatory stage to enhnace the performance 
                         (Q-factor) of the niobium superconducting cavities, which play the 
                         role of parametric transducers at the Mario Schenberg 
                         gravitational wave detector, located in the astrophsical 
                         department at INPE. In this work the respective cavities were 
                         treated by electropolishing (EP) and Plasma Based Ion Implantation 
                         (PBII), leading to an increase of the Q-factors by up two orders 
                         of magnitude. While EP is responsible for chemically removing the 
                         outer layer of the machined cavities, N-PBII is employed to 
                         implant nitrogen ions into Nb. In addition, Ar-PBII performed 
                         afterwards at high temperature (substrate heated) is a fundamental 
                         step used to remove contaminants (C and O) from the surface of Nb. 
                         A systematic investigation has been performed by strictly 
                         adjusting the parameters of the processes in order to reduce at 
                         maximum the amount of contaminants on the surfaces and to control 
                         the nitrogendoping, an important impurity to avoiod the formation 
                         of niobium hydrides, compounds with very low critical 
                         temperatures, as previously reported by experiments performed in 
                         Fermilab with Nb superconducting cavities1 . A set of 
                         characterization methods involving MEV/EDS, XRD and XPS were used 
                         to monitoring the morphology/elemental analysis, phase phormation 
                         and the chemical state of the elements, respectively. A 
                         correlation of the Q-factors (measured at 4k) with the chemical 
                         composition of the elements present on the surface of Nb is 
                         demonstrated, indicating a clear path to attain high performance 
                         of the cavities, helping with the enhancement of the sensitivity 
                         of the Mario Schenber detector.",
  conference-location = "Online",
      conference-year = "23 a 26 nov.",
        urlaccessdate = "10 maio 2024"
}