The creation of the LNLS Users Group (LNLSUG) began during the 28th Annual Users Meeting (RAU), held in 2018 under the coordination of Leopoldo Suescun (Udelar, Uruguay). During the closing session, the formation of a Users Group was proposed by Eduardo Granado (UNICAMP) and promptly accepted by the community. It was then established that a working group would be formed with the mission of drafting a set of bylaws to be presented at the following year’s RAU. Members involved in organizing the 28th and 29th RAU were invited to join this initial group.
Between 2018 and 2019, this group conducted discussions, primarily via electronic communication, to prepare the LNLSUG bylaws. The process involved Eduardo Granado, Leopoldo Suescun (Udelar, Uruguay), Maria Luiza Rocco (UFRJ), Felix G. Requejo (INIFTA, Argentina), Roberto Magalhães Paniago (UFMG), Maria do Carmo Martins Alves (UFRGS), Flávio Garcia (CBPF), Regina Cély Barroso (UERJ), Rafael V. C. Guido (IFSC-USP), and Mário E. G. Valerio (UFS).
The bylaws were presented during the 29th RAU in 2019, under the coordination of Maria Luiza Rocco, and were approved by the Users Assembly. The document provided for the creation of a provisional committee composed of three members appointed by the LNLS management, responsible for organizing the first elections of the Users Committee, to be held prior to the 2020 RAU.
In the period from 2019 to 2020, the provisional committee was established, consisting of Eduardo Granado, Maria Luiza Rocco, and Regina Cély Barroso.
The first elections of the LNLS Users Group Committee took place during the 30th RAU in 2020, held virtually and coordinated by Regina Cély Barroso. Exceptionally, six positions were opened, with staggered terms as defined in the bylaws: Gustavo Azevedo (UFRGS) and Claudia Rodriguez Torres (UNLP, Argentina) were elected for one-year terms (2020–2021); María Fernanda Mera (CEPROCOR, Argentina) and Hudson W. Carvalho (USP), for two-year terms (2020–2022); and Eduardo Granado (UNICAMP) and Daniela Zanchet (UNICAMP), for three-year terms (2020–2023). Regina Cély R. Barroso (UERJ) and Maria Luiza Rocco (UFRJ) remained on the committee, due to their roles as coordinators of the 29th and 30th RAU.
Since then, the LNLSUG Committee has been renewed annually during the RAU, with the following composition over the years: