LNLS, Campinas, Brazil
MI-Partners, Eindhoven, The Netherlands
LNLS, Campinas, Brazil
MI-Partners, Eindhoven, The Netherlands
The monochromator is known to be one of the most critical optical elements of a synchrotron beamline, since it directly affects the beam quality with respect to energy and position. The new 4th generation machines, with emittances in the range of order of 100 pm rad, require even higher stability performances, in spite of the still conflicting factors such as high power loads, power load variation, and vibration sources. A new high-dynamics DCM (Double Crystal Monochromator) is under development at the Brazilian Synchrotron Light Laboratory for the future X-ray undulator and superbend beamlines of Sirius. Aiming at an inter-crystal stability of a few tens of nrad (even during the Bragg angle motion for flyscans) and considering the limitations of current DCM implementations, several aspects of the DCM engineering are being revisited. In order to achieve a highly repeatable dynamic system, with a servocontrol bandwidth in the range of 200 Hz to 300 Hz, solutions are proposed for a few topics, including: actuators and guides, metrology and feedback, LN2 indirect cooling, crystal clamping, thermal management and shielding. The concept of this high-dynamics DCM will be presented.
LNLS, Campinas, Brazil
MI-Partners, Eindhoven, The Netherlands
The monochromator is known to be one of the most critical optical elements of a synchrotron beamline, since it directly affects the beam quality with respect to energy and position. Naturally, the new 4th generation machines, with their small emittances, start to bring about higher stability performance requirements, in spite of factors as high power loads, power load variation, and vibration sources. A new high-dynamics DCM (Double Crystal Monochromator) is under development at the Brazilian Light Source for the Sirius EMA beamline (Extreme Condition X-ray Methods of Analysis). In order to achieve high-bandwidth control and stability of a few nrad, as well as to prevent unpredicted mounting and clamping distortions, new solutions are proposed for crystal fixation and thermal management. Since the design is based on flexural elements, it should be indeed highly predictable, so that the work was developed using mechanical and thermal FEA, including CFD. Efforts were made to predict thermal boundaries associated with the synchrotron beam, including incident, diffracted and scattered power, for which the undulator spectrum was employed in the Monte Carlo simulation package - FLUKA *.
* "FLUKA: a multi-particle transport code", A. Ferrari, P.R. Sala, A. Fasso‘, and J. Ranft, CERN-2005-10 (2005), INFN/TC05/11, SLAC-R-773
LNLS, Campinas, Brazil
Currently under construction on Brazilian Synchrotron Light Laboratory Campus, Campinas/SP, Sirius is a 3GeV, 4th Generation Synchrotron Light Source. In this paper we describe the Front End that has been designed to transmit the intense synchrotron radiation generated by the insertion devices that will generate the most critical thermal stress, with a peak power density of 55.7 kW/mrad² and a total power of 9.3kW at 500mA in the storage ring. The functions of the main components and their location in the layout are described. Computational fluid dynamics (CFD) and structural simulations, that have been carried out to verify the performance under the high heat loads generated by Sirius, are also detailed along with the limits of temperature and stress that have been employed in the design.