Development of aluminum ultrahigh vacuum chambers for optical elements at Sirius beamlines

• Grant number: 16/50041-3
• Support Opportunities: Research Grants - Innovative Research in Small Business - PIPE
• Start date: June 01, 2018
• End date: February 28, 2021
• Field of knowledge: Physical Sciences and Mathematics - Physics - General Physics
• Agreement: FINEP - PIPE/PAPPE Grant
• Principal Investigator: Osmar Roberto Bagnato
• Grantee: Osmar Roberto Bagnato
• Company: FCA Brasil Indústria, Comércio e Usinagem de Peças Ltda. EPP
• City: Campinas

Abstract

The design and construction of Sirius will increase the possibilities and quality of synchrotron research in Brazil. The entire synchrotron radiation production and most of the experiments performed with it, occur in ultra-high vacuum (UHV) systems. Nowadays, most of the UHV chambers are built of stainless steel, and the FCA Brazil has all the know-how and manufactures such chambers. However, in the light of modern knowledge, we observed that in several aspects the stainless steel is not the best option. As an example, we have aluminum, which among other characteristics presents an outgassing rate an order of magnitude lower than that of stainless steel. Additionally aluminum also has much lower hydrogen permeability than stainless steel, is non-magnetic, its thermal conductivity is ten times higher, is lighter and can be machined up to ten times faster. These last two features, along with the lower cost of raw materials, further reduces the cost of production and transportation of UHV chambers that are produced in aluminum. Other advantages could also be presented such as the case of optical elements: Reduction of Sirius beam size compared to LNLS will result in a reduction in size of optical elements, which together with the lower weight of aluminum chambers will allow the placement of the positioning system of the optical elements outside the chambers, simplifying its maintenance. For these, among other reasons, we propose to develop UHV aluminum chambers for optical elements of Sirius. The challenges that lies before us are mainly the quality of the welds and bonds needed to achieve UHV and the compatibility of these chambers connections with the rest of the system. To overcome both challenges we will promote systematic studies of TIG (Tungsten Inert Gas) welding on aluminum and diffusion bonding of aluminum and stainless steel for the development of bi-metallic flanges. Achieved the objectives, FCA Brazil besides being the Brazilian pioneer in providing stainless steel UHV chambers will also fabricate aluminum UHV chambers, contributing to the scientific and technological autonomy of the country in the sector and enabling the national industry enter this market currently explored only by a few international industries. (AU)