NSRRC Activity Report 2022

104 NSRRC ACTIVITY REPORT 2022 The DCM mode provides a source for stable and clean images, as well as higher-energy resolution. However, the X-ray intensity provided by the DMM mode is approximately 20 times stronger than that provided by the DCM mode, which is in line with the calculations. The research team conducted experiments using both DCM and DMM and found that, by using the beam provided by DCM, it was possible to achieve approximately 20 ms per image, whereas by using the beam provided by DMM, it was possibly to achieve approximately 1 ms per image. Using DCM mode, it was also possible to complete full- resolution X-ray tomography, including 1440 projection images of 2560 × 2180 pixels and two reference images with the same pixel resolution. This was tested using a weak absorption sample and found to reach approximately 2/3rds of the maximum counts of the detector. To take a complete tomography data set requires a certain degree of overhead for speeding up the rotation stage, slowing down the stage, removing the sample, and taking the reference images. This process takes approximately 75 s to complete, or an average of 50 ms per image. To achieve the aforementioned resolution for a tomography scan, currently the DMM mode takes approximately 45 s to complete. The average time per image is approximately 31 ms, which is significantly different to the previous time of 1 ms per image. The main reason for this is that the currently used light detector (Andor Zyla) has a maximum frame rate of only 100 images per second. Therefore, if using a faster detector (such as NAC-ACS1 m60) is expected to improve the current time of 45 s to approximately 2 s without reference images. Automation Integration of the Experimental Station The sample automatic exchange system 4 of the experimental station is built on the automatic loading of multiple samples on a sample tray and the use of a robotic arm to place the sample holders on the sample tray onto the test position of the experimental station, as shown in Fig. 2 . To fully automate the process, the research team first places the sample holders on the pre- designed sample tray and uses an automated program on a 2D contour measuring instrument to locate the samples in 3D space. After the samples are positioned, the tray is placed into a conveyor box (magazine) located in the experimental station and then placed onto the test position by the robotic arm. An online video can be found via the reference. 5 At this time, the three-dimensional positioning data on the 2D contour measuring instrument will be transmitted to the computer controlling the experimental station, which enables the tomography scan to be performed directly without consuming valuable time for beamline alignment. In this automated system, the sample tray is a 5 × 8 sample space and each conveyor box can hold eleven trays. The system contains two transport boxes and the system can store up to 880 sample seats. Currently, the estimated time for each sample is up to one minute minus the time for the robotic arm to pick it up, which is approximately 1.5 minutes. Therefore, a storage capacity of 880 samples can last for approximately 24 hours. If it remains possible to simultaneously use the 2D contour measuring instrument to make measurements, then it will be possible to continue to perform tomography scanning work. Processing of the Tomography Data Due to the fast pace of the experiments, the system’s corresponding data storage system is 1.0 PB and each set of data was calculated at approximately 10 GB, which is sufficient for approximately 100,000 sets of data. With 500 sets of data per day, this is approximately 200 days, or almost one year of data storage capacity. After the data was acquired, a self-made program was used to perform the tomography reconstruction. For a full data set of 1440 projection images of 2560 × 2180 pixels, it takes around two minutes to complete the reconstruction calculation for a typical personal computer. Thus, this program can be installed on a general user’s Fig. 2 : (a) Schematic drawing of the automatic sample loading/unloading system. (b,c) Photographs of the automatic sample loading/unloading system.