BM18, the New ESRF-EBS Beamline for Hierarchical Phase-Contrast Tomography
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F. Cianciosi, A.-L. Buisson, P. Tafforeau, P. Van Vaerenbergh
ESRF, Grenoble, France
BM18 is an ESRF-EBS beamline for hierarchical tomography, it will combine sub-micron precision and the possibility to scan very large samples. The applications will include biomedical imaging, material sciences and cultural heritage. It will allow the complete scanning of a post-mortem human body at 25 µm, with the ability to zoom-in in any location to 0.7 µm. BM18 is exploiting the high-energy-coherence beam of the new EBS storage ring. The X-ray source is a short tripole wiggler that gives a 300mm-wide beam at the sample position placed 172m away from the source. Due to this beam size, nearly all of the instruments are devel-oped in-house. A new building was constructed to ac-commodate the largest synchrotron white-beam Experi-mental Hutch worldwide (42x5-6m). The main optical components are refractive lenses, slits, filters and a chop-per. There is no crystal monochromator present but the combination of the optical elements will provide high quality filtered white beams, as well as an inline mono-chromator system. The energy will span from 25 to 350 keV. The Experimental Hutch is connected by a 120m long UHV pipe with a large window at the end, followed by a last set of slits. The sample stage can position, rotate and monitor with sub-micron precision samples up to 2,5x0.6m (H x Diam.) and 300kg. The resulting machine is 4x3x5m and weighs 50 tons. The girder for detectors carries up to 9 detectors on individual 2-axis stages. It moves on air-pads on a precision marble floor up to 38m behind the sample stage to perform phase contrast imag-ing at a very high energy on large objects. The commissioning is scheduled for the beginning of 2022; the first ’friendly users’ are expected in March 2022 and the full operation will start in September 2022.
Development of a Linear Fast Shutter for BM05 at ESRF and BEATS at SESAME
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C. Muñoz Pequeño, J.M. Clement, P. Thevenau, P. Van Vaerenbergh
ESRF, Grenoble, France
This paper presents the design of a new linear fast shutter for topography and tomography. A prototype will be assembled and tested at the BM05 beamline at ESRF, and another unit will be installed in the future BEATS beamline at SESAME. The application of the shutter in X-ray diffraction topography allows performance of long exposure cycles of monochromatic beam on crystal samples while preventing irradiation of the detector during readout. It can be also used during sample alignment and acquisition of X-ray tomography scans. Particularly for white-beam tomography, which uses a very high photon flux, minimizing exposure is critical to protect the sample and detector from radiation damage. This highlights the importance of obtaining a short and uniform exposure time over the beam aperture. To fulfill this objective, a new shutter based on the synchronization of two tantalum blades driven by linear brushless DC motors is under development. This versatile design can be used with both monochromatic and white-beam, and it can achieve exposure times ranging from 50 ms to 60 s for a beam size of H 80 mm x V 20 mm. The linear motors allow for a much smoother operation, preventing vibration issues reported with the old shutter. In addition, the use of linear motors rather than solenoids allows an unlimited exposure time, where the previous version used solenoids that could overheat if kept open for too long. A test bench has been constructed for the characterization of the sequence produced by the linear motors, and exposure times of 50 ms with a maximum error of 1 ms have been measured. This article describes the main features of the shutter prototype and its associated motion control system, and the results of the measurements with the motor test bench are discussed as well.
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Design and Ray-Tracing of the BEATS Beamline of SESAME
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G. Iori, M.M. Al Shehab, M.A. Al-Najdawi, A. Lausi
SESAME, Allan, Jordan
M. Altissimo, I. Cudin
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
A. Kaprolat, J. Reyes-Herrera, P. Van Vaerenbergh
ESRF, Grenoble, France
T. Kolodziej
NSRC SOLARIS, Kraków, Poland
Funding:EU H2020 framework programme for research and innovation. Grant agreement n°822535. The BEAmline for Tomography at SESAME (BEATS) will operate an X-rayμtomography station providing service to scientists from archaeology, cultural heritage, medicine, biology, material science and engineering, geology and environmental sciences*. BEATS will have a length of 45 m with a 3-pole-wiggler source (3 T peak magnetic field at 11 mm gap). Filtered white and monochromatic beam (8 keV to 50 keV, dE/E: 2% to 3% using a double-multilayer-monochromator) modalities will be available. In this work we present the beamline optical design, verified with simulation tools included in OASYS**. The calculated flux through 1 mm2 at the sample position will be as high as 8.5×109 Ph/s/mm2 in 0.1% of the source bandwidth, for a maximum usable beam size of 70×15 mm2. Beam transverse coherence will be limited to below 1 µm by the horizontal size of the X-ray source (~2 mm FWHM). For phase contrast applications requiring enhanced coherence, front end slits can be closed to 0.5 mm horizontally, with a reduction of the available beam size and photon flux. The BEATS beamline will fulfill the needs of the tomography community of SESAME. * H2020 project BEATS, Technical Design Report (July 2020). ** L. Rebuffi and M. Sanchez del Rio, Proc. SPIE 10388: 130080S (2017).
An FEA Investigation of the Vibration Response of the BEATS Detector Stage
T.F. Mokoena, A. Kaprolat, P. Van Vaerenbergh
ESRF, Grenoble, France
M. Bhamjee, S.H. Connell
University of Johannesburg, Johannesburg, South Africa
G. Iori
SESAME, Allan, Jordan
As for all Synchrotron Radiation based installations, floor vibrations lead to unreliable results if transmitted to sensible equipment like sample environment and detection systems. It is important to design the optical and experimental equipment of a beamline in a way to minimize the effect of the vibrations. This project investigates the design of the detector stage in SESAME’s tomography beamline BEATS by using random vibration analysis to determine the rigidity of the structure. The design analysis of the detector stage takes the approach of using an existing installation at beamline ID28 of the European Synchrotron Radiation Facility by measuring the power spectrum density of the floor on which the structure is mounted on as well as the response of the structure stage as it is subjected to an excitation from ambient floor noise. A finite element analysis numerical model was established and validated against the experimental data. Once the model is validated within acceptable range, the technique will be applied to the BEATS detector stage design by applying the floor power spectrum density of the SESAME synchrotron and calculating the response of the structure. It is assumed that the random vibration process in this case follows a Gaussian normal distribution. The response power spectrum density Root Mean Square value at the location of interest should be at least 6 times less than the pixel size of the camera that will be used in detector. For the ID28 case, the model was validated by comparing the natural frequency measured and the experimental output RMS value against the model output RMS value. The model natural frequencies deviated from the experimental results by 4.53% and the model RMS values deviated from the experimental results by 1.91%.
