MicroCT Imaging Consortium for Research and Outreach

The UArk microCT system is optimized for imaging of a variety of different materials of a range of different densities and sizes. The specific system at the heart of MICRO is a Nikon X TH 225 ST µCT system. This system comes equipped with a 225 kV X-ray tube with a fixed reflection target, which can generate 225 watts (W) of power with a minimum focal spot size of 3 microns (µm). The addition of a 180 kV transmission target (i.e., nano-focus tube) further allows this system to generate a focal spot size of 1 µm and image objects down to the sub-micron level. The MICRO equipment also has a 225 kV rotating target, which makes this system capable of generating up to 450 W of power that can penetrate exceptionally dense materials. With these three interchangeable X-ray sources, this system has the flexibility to image items with voxel resolutions from ~1 µm to 225 µm. The 2000 x 2000 active pixels of the detector panel allow for the examination of objects up to 21 cm in diameter and 50 cm in height, and the maximum sample weight of the system is 50 kg. A motorized detector (i.e., focal spot to imager distance [FID]) enables the rescaling of the system for objects of different sizes in a minimum amount of time, maximizing workflow and reducing individual user costs. The system is fully radiation shielded and generates less than 1 microSievert (µSv) per hour on all external surfaces of the equipment. UAF has a current X-ray license (# CU00004, type XRA11) issued by the Arkansas Department of Health, all µCT users receive X-ray training, and radiation signage is posted in the vicinity of the µCT equipment.

The MICRO system is fully radiation shielded and certified by Nikon, the University of Arkansas, and the Arkansas Department of Health (X-ray license # CU00004, type XRA11). The system includes multiple interlocks to ensure that x-rays are not produced when the cabinet door is open. According to the radiation survey conducted in April 2018 (upon installation of the equipment) all radiation readings on the surface of the equipment when the equipment was at full power are <0.03 milliRoentgen per hour, which is roughly equal to 0.026 millirem per hour.