Sirius has in its heart particle accelerators responsible for accelerating electron beams to very high speeds, very close to the speed of light, and for keeping them circulating in stable orbits for several hours in ultra-high vacuum, while producing synchrotron light. Each of these electron bunches has, in some sections of the accelerator, only 1.5 micrometers of vertical size, that is, about 50 times smaller than a strand of hair.
These tiny bunches must travel a circular path of 500 meters in circumference, 600,000 times every second, for hours, without their position oscillating more than a tenth of their size. This is important because the more stable and focused the electron beams circulating in the particle accelerators, the better and brighter the synchrotron light produced and delivered to the researchers.
There were many challenges for the construction of the facilities that house Sirius, from the stability of the floor against deformations and the isolation of internal and external vibrations to the thermal stability of the environments and components. All construction aspects, from the foundation to the roof, had to consider unprecedented mechanical and thermal stability requirements.
Hence, the building is an essential part for the operation of this complex machine, which is why it is one of the most advanced civil constructions ever made in Brazil.
The foundation of the building is divided into two sections totally independent from each other: the first supports the building structure and the second supports the floor of the accelerator and experimental areas. The foundation of the accelerator area consists of around 1300 concrete piles, 15 meters long, carefully placed under almost three meters of modified soil with a high degree of compaction.
The floors that support the accelerator area and the beamline region are made of reinforced concrete, 90 and 60 centimeter thick, respectively. The floors are extremely flat: throughout its area, of 17 thousand square meters, the difference in height between the lowest point and the highest point of the floor is less than two centimeters.
The tunnel that houses the electron accelerators has a length of more than 500 meters, built as a monolithic piece of reinforced concrete. The accelerator tunnel has walls and roof between 80 centimeters and 1.5 meters thick.
The temperature inside the accelerator tunnel must be very well controlled with a maximum variation of plus or minus 0.1 °C. Also in the experimental area, good temperature control is required, with a maximum variation of plus or minus 0.5 °C.
Utility pipes are oversized, reducing fluid transport the speeds and the generation of vibrations during their propagation. Utility pipes are also suspended by springs to dampen the vibrations.
Covering a floor area of 68,000 square meters, the main Sirius building have four floors with capacity for up to 620 people, including employees and visitors. The predominantly circular shape of the building is a result of the geometry of the particle accelerators where electrons are stored, and synchrotron light is produced.
In 2013, an area of 150 thousand square meters, adjacent to CNPEM, was expropriated by the State Government of São Paulo to build Sirius. In the same year, the earthworks began, completed in 2014. On December 19, 2014, the contract was signed with the construction company and the cornerstone of the construction works was laid.
In January 2015, the construction works began. By the end of that year, almost 20% of construction works were completed. In 2017, construction works reached 75% completion, with the successful execution of the most critical phase of construction: the implementation of the special floor on which accelerators and beamlines were later installed. In 2018, civil works were completed, and the installation of equipment began.