The diffraction-limited Montel mirrors, equipped at the X-ray Nanoprobe (XNP) at Taiwan Photon Source (TPS), provide a 40 nm focal spot and working distance 55 mm under the total beamline length of 69 m. The underneath holder supporting for the Montel mirrors is a 12 axes flexure based manipulators in which 10 out of the 12 axes are motorized. To monitor the position and stability of individual holder motion, a monitoring system consisted of three optical encoders and three- axes laser interferometers for angle movement is implemented. The gap width between the two mirrors and their orthogonality can be adjusted by a tilting sensor and a high magnification optical microscope. The focusing properties, phase and amplitude, after the Montel mirrors will be investigated by means of coherent Ptychography, as well as by zone plate imaging. An SEM in close cooperation with laser interferometers is equipped to precisely position the samples and conduct the on-the-fly scan. A high speed FPGA based circuit is developed to address signal from XRF, XAS, XEOL and XRD. Data is in tag with position and time information and been processed by computers to allow 5nm precision stage scanning free from mechanical feedback. The XNP at TPS is under commissioning since February 2017. The commissioning result, particularly the performance of the Montel mirrors will be reported in this presentation.
This on-the-fly scanning control system is for the x-ray nanoprobe endstation at Taiwan Photon Source(TPS) and built base-on the high speed Hardware (H/W), high throughput data stream and multi-channel control interfaces. The main idea is to tag each data with information of time and position, which generates by circuit and laser interferometer. The data is then processed by a computer to be analyzed and visualized.
By using high speed FPGA with embedded processer to process the input and output data which includes the DAC, ADC, Gigabit Ethernet (GbE), X-ray fluorescence (XRF) and laser interferometer control interfaces. Three DAC control the X,Y and Z axes of the flexure stage, four ADCs and sensor interfaces gather the data and packet it into data packet. GbE send data back to computer to do image processing then reconstruct the scanning image. The numerous data not only for rebuild the image but also good for information analysis. Including the vibration, time slide analysis.
Our demo system is built by an e-beam source, flexure stage and laser interferometer. The current maximum scanning speed is up to 5 lines/sec which is limited by the mechanical, the sample rate can be as high as 20M samples/sec which limited by laser interferometer, and the maximum data rate is close to 100M bytes/sec which is limited by the GbE. Interferometer information combine with position data in data packet, makes easy for data analysis and also for image stitching. The system is going to commission on beamline at March, 2017. The commission result for this system will be presented.
The hard X-ray nanoprobe at Taiwan Photon Source (TPS) makes use of the large numerical aperture obtained by nested Montel mirrors. To fully uptake the focusing power and flux, these mirrors requires the surface slope error no less than 0.05 μrad and are symmetrically placed with a 45 degrees cut for perfect surface matching. The beamline optics is designed to take the advantage of the symmetry of mirrors such that a round focal spot is accomplished. The final size of the focus spot are simulated below 40 nm at 9-15 keV. The whole facility including the beamline and the stations will be operated under vacuum to preserve photon coherence as well as to prevent the system from unnecessary environmental interference. The station equips with multimodal x-ray probes, including XRF, XAS, XEOL, projection microscope, CDI, etc. A SEM in close cooperation with laser interferometers is equipped to precisely locate the position of the sample. The beamline and the station are scheduled to be in commissioning phase in 2016.