Beamline 1.2W (BL1.2W) is a new beamline dedicated to X-ray imaging and computed microtomography (commonly referred to as Micro-CT; µCT). The experiments at the BL1.2W will be carried out based on the “Synchrotron radiation X-ray tomographic microscopy (SRXTM)” technique, which is a non-destructive technique for visualization and analysis of the internal features of solid opaque objects.
Beamline BL1.2W layout:
BL1.2W is designed to utilize hard X rays from a 2.4 Tesla multipole wiggler (MPW) to generate X-ray images. From the MPW, polychromatic X-ray beam will be optimized with white-beam slits (WB slit) and toroidal focusing mirror (FM), respectively. Altogether, these will define the X-ray beam up to 8 x 4 mm (H x V) at the sample position. Low energy X rays (<4 keV) are filtered by the beryllium window (Be window) allowing high energy X rays to enter the experimental hutch for X-ray imaging and microtomography experiments. The X-ray intensity can be further adjusted by an attenuator, which consists of a series of aluminum foils. At BL1.2W, X-ray images are generated with a microscopic lens system and recorded by an sCMOS camera. Hypothetical specification of BL1.2W is listed in the table below.
Figure 1 Beamline BL1.2W layout and technical specification.
Figure 2 Beamline BL1.2W structure.
Figure 3 Experimental hutch of BL1.2W (commissioning mode).
X-ray imaging and SRXTM experiment
When an object is exposed to X rays, the differences in the effects on the passage of waves of energy reacting with its internal structures will be collected and converted to visible light by a scintillator. Then it will pass through a microscopic lens system and will be recorded as digital signals by the sCMOS camera. X-ray images can be produced up to 5.5 megapixels (2560 x 2160). With this system, BL1.2W is able to bring X-ray imaging a resolving power of 1 µm (1/1000 mm) as maximum resolution. Contrast of resulting images depends on attenuation coefficient of the object matters according to Lambert Beer's law (the transmitted intensity formula below). At BL1.2W, users will opt for better magnification and resolution with 2X, 5X, and 10X objective lens. A dataset of X-ray images will be processed into ‘sinograms’, which will be used in the reconstruction of CT slices. Stack of these resulting CT slices will make 3D of the object allowing for investigation and visualization of matters inside.
Lambert Beer’s law
Figure 4 Tomographic reconstruction procedure
X-ray image of a random bug
3D tomography of human bone
3D tomography of bamboo toothpick
Figure 5 Examples of x-ray image and reconstructed 3D tomography obtained from BL1.2W (commissioning mode).
Catleya Rojviriya, Ph.D.
Tel: 1431, 1690
Phakkhananan Pakawanit, Ph.D.