Micro nano CT machineMicro nano computed tomography (CT) is an advanced imaging device that combines micro nano focal X-ray sources with high-precision detection systems. Its core breakthrough lies in increasing the resolution of traditional CT to the micrometer to nanometer level, becoming a key tool for microstructure analysis in fields such as materials science, biomedical science, and geological archaeology. It penetrates the sample by emitting X-ray beams with micro nano focal points (usually less than 1 micron in diameter), uses detectors to receive transmission signals from different angles, and combines computer tomography reconstruction algorithms to generate three-dimensional images.
Micro nano CT machineOperation process:
1、 Preparation before operation
Environmental inspection:
Confirm that the operating environment of the equipment meets the requirements: temperature (usually 20-25 ° C), humidity (40-60%), no vibration, and no strong electromagnetic interference.
Ensure that the equipment (especially the X-ray source and detector) is in a stable state (preheating).
Sample preparation:
Size and weight: Confirm that the sample size and weight are within the load-bearing range of the equipment sample stage.
Fixation: use appropriate clamps (such as double-sided adhesive tape, foam, special sample clamp) to firmly and stably fix the sample on the sample table. The sample must remain absolutely stationary during the scanning process, as any slight movement can cause image blurring.
Cleaning: Ensure that the sample surface is clean, free of dust, oil stains, etc.
Safety: Confirm that the sample is non radioactive, non corrosive, non-volatile (or sealed), and will not damage equipment or harm operators.
Personal protection:
Wear necessary personal protective equipment (such as lead aprons, lead goggles, according to the radiation level requirements of the equipment).
Confirm that the scanning room door is closed and the safety interlock device is effective.
2、 Sample loading and positioning
Open the scanning room: According to the regulations, open the protective door or hatch of the equipment.
Installation of sample table: Carefully install the sample table containing the sample onto the rotating table (turntable) and ensure that it is installed in place and locked.
Close the scanning room: Carefully close and lock the protective door/hatch.
3、 Software startup and system initialization
Startup control software: Open the computer and start the device specific CT control and reconstruction software (such as Zeiss Scout and Scan, Bruker CTVox, Nikon CT Pro, etc.).
System connection: After software startup, check if it successfully connects to hardware such as X-ray sources, detectors, and rotating tables.
System preheating/stabilization (if necessary): Some devices may require a brief preheating or stabilization time.
4、 Scanning parameter settings and preview
X-ray source settings:
Voltage (kV): Select based on the material and thickness of the sample. High density/thick samples require higher voltage.
Current (μ A): Affects X-ray intensity and image signal-to-noise ratio. The power is determined jointly with the voltage.
Focus size: Choose micro focus or nano focus to affect resolution.
Detector settings:
Integral time/exposure time: affects image brightness and signal-to-noise ratio. The longer the time, the better the signal-to-noise ratio, but the longer the scanning time.
Resolution mode: Select the pixel binning mode of the detector (such as 1x1, 2x2), which directly affects the image resolution and field of view (FOV).
Scanning geometry settings:
Magnification factor: controlled by adjusting the distance between the sample and the X-ray source (SOD) and the sample and detector (SDD). Magnification factor=SDD/SOD. Higher magnification brings higher resolution, but smaller field of view.
Scanning angle range: usually 180 ° or 360 °. 360 ° can obtain more complete data and reduce artifacts.
Projection count: The number of two-dimensional images collected. The more quantity, the higher the reconstruction quality, but the longer the scanning time (usually 500-3000 images).
Preview/Live View:
Activate low-dose real-time imaging mode.
Observe the position and brightness of the sample on the detector.
Adjust sample position: Use software controlled XYZ translation stage to precisely move the region of interest (ROI) of the sample to the center of rotation (axis).
Adjust focus position: Ensure that the sample is located at the center of the X-ray beam and in the optimal focal plane.
Optimize contrast: Fine tune kV, μ A, and exposure time to make the image grayscale distribution reasonable (avoid overexposure or underexposure).
5、 Formal scan
Confirm parameters: Check again if all scanning parameters are correct.
Start Scan: Click on "Start Scan" or a similar button.
Monitoring process: During the scanning process, observe the software interface to monitor the scanning progress, X-ray source, and detector status. It is strictly prohibited to open the scanning room door.
Scan completed: After the scan is completed, the software usually prompts. The X-ray source automatically shuts down.
6、 Image reconstruction
Choose reconstruction algorithm: Typically, the Filter Back Projection (FBP) algorithm is used. For low-dose or sparse data, iterative reconstruction algorithms can be chosen.
Set reconstruction parameters:
Reconstruct volume size: determines the resolution (voxel size) of 3D volume data.
Filter: Choose appropriate convolution kernels (such as Hanning and Hamming filters) to optimize image quality and reduce artifacts.
Center position correction (optional): If the axis is not fully aligned, fine adjustments can be made.
Start rebuilding: Start the rebuilding program. The reconstruction time depends on the amount of data and computer performance, and may range from a few minutes to several hours.
View results: After the reconstruction is completed, load the 3D data and view the cross-sectional, coronal, and sagittal images in the software to check the image quality (clarity, artifacts, noise).
7、 Post processing and analysis
Image processing:
Noise reduction: Apply Gaussian filtering, median filtering, etc. to remove noise.
Enhancement: Adjust window width and level to optimize contrast.
Segmentation: Using methods such as thresholding and region growth to separate different phases (such as pores, matrix, inclusions).
3D visualization: rendering the segmented data in 3D to generate intuitive stereoscopic images.
Quantitative analysis:
Measure volume, surface area, porosity, pore size distribution, wall thickness, crack length, etc.
Perform particle analysis (particle size, shape).
Data export: Export reconstructed volume data, analysis results, images or videos to the desired format (DICOM, TIFF, STL, CSV, etc.).
8、 End operation
Unloading samples: After opening the scanning room door, carefully remove the samples and sample table.
Cleaning: Clean the sample table and keep the equipment clean.
Shut down software and devices: Turn off control software and device power according to regulations (if necessary).
Record: Detailed records of the parameters, sample information, operators, and results of this experiment, forming an experimental log.