LNLS, Campinas, Brazil
LNNano, Campinas, Brazil
Sirius, the new Brazilian fourth-generation synchrotron light source, is currently under construction. Due to the high brilliance and low emittance of its source, the pho-ton beam on each undulator beamline can have power densities as high as 55 W/mrad². To protect the compo-nents downstream, the Front-End power absorbers need to manage this power in a limited space, but also having precision in alignment and being reliable all over their lifetime. To achieve this behaviour, the selected alloy was the copper-chromium-zirconium (CuCrZr, commercially known as C18150) because of improved thermal and mechanical properties. In order to seal the vacuum cham-ber (path on which the cooling water flows), friction stir welding was the selected joining method. During the welding process, the material passes through a grain re-finement process which results in a high-resistance joint. The manufacturing process could also result on a reduc-tion of costs and lead times. Finally, it will be presented the final versions of the component with its support and the characterizations done to validate the welded joint under vacuum and water pressure requirements.
LNLS, Campinas, Brazil
The first set of Sirius beamlines is expected to start operating in early 2019. Regarding X-ray mirror sys-tems, a single design concept has been possible thanks to the standardization of side-bounce fixed-shape mirrors. To preserve the extreme quality of both the mirror figures and the source, the main design targets were minimizing mechanical and thermal distortions in the mirrors while maximizing mechanical and thermal stabilities. A deterministic high-resolution exactly-constrained flexure-based mirror support provides pitch tuning within 100 nrad and resonances above 150 Hz, while dealing with clamping and thermal ex-pansion effects. The adopted cooling strategy was indirect cryocooling via cryostats, drastically minimiz-ing thermal gradients and distortions in the mirrors, decoupling vibration sources and simplifying cooling circuits. Finally, a 5-degree-of-freedom granite bench, based on high-resolution levellers and air-bearing solutions, support the vacuum chamber, on which the internal mechanics is stiffly mounted. The specifica-tions, design and partial results are presented.
LNLS, Campinas, Brazil
The mirrors for Sirius, the new 4th-generation synchrotron at the Brazilian Synchrotron Light Laboratory (LNLS), have strict requirements regarding thermo-mechanical stability and deformations, with figure height and slope errors limited to a few nanometers and tens of nanoradians, respectively. Therefore, fixed-shape mirrors have been defined with horizontally-reflecting orientation (except for vertically-reflecting mirrors of KB systems), whereas their cooling schemes (namely, air, water or liquid nitrogen cooling) depend on the particular power load. A thermal and mechanical optimization method was developed to guide the design of mirrors through the evaluation of deformations caused by power load, cooling, gravity, tightening of the fastening screws, manufacturing errors and modal analyses. Up to now, this method was already used to define the mirrors of Sirius' beamlines, which include plane, cylindrical, elliptical and ellipsoidal mirrors, as well as KB systems for microprobe and nanoprobe stations. Two examples are presented to illustrate the method.
LNLS, Campinas, Brazil
A Front End (FE) prototype for a 19-mm period length Adjustable Phase Undulator (APU19) beamline of the new Brazilian 4th-generation synchrotron, Sirius, was assembled in the LNLS metrology building in January 2017 to validate main design concepts. Regarding stability, flow-induced vibration (FIV) investigations were carried out on the water-cooled components, and modal analyses were made on the X-Ray Beam Position Monitor (XBPM) support. As for the vacuum system, final pressure levels were investigated and a vacuum breach was intentionally provoked to verify the performance of the equipment protection system (EPS). In addition, cycling tests of the Photon and Gamma shutters were conducted to verify the FE reliability. Moreover, the three-layer protection system, developed to limit the maximum aperture for the high-power slits, was functionally evaluated. Finally, the results were used to improve the FE to its final design. This paper describes the tests setups and results obtained during the validations.