The imaging instrument at DanMAX has been designed to offer maximum flexibility across a wide spectrum of experimental types and modalities, accommodating a diverse range of samples and sample environments. To facilitate in situ and in operando measurements, the instrument offers a relatively high temporal resolution. Specifically, the DanMAX imaging instrument is engineered to execute a tomography scan in under one second, a feat achieved through a judicious compromise among factors like spatial resolution, dynamic range, signal-to-noise ratio, and temporal resolution.
Installation and Experimental Capacity
Anticipated for installation in October/November 2023, this cutting-edge instrument will initially support parallel beam projection medium-resolution tomography, encompassing both absorption and phase contrast techniques. As the facility evolves, additional modalities, such as higher-resolution holography and X-ray microscopy, will become available at a later stage.
The DanMAX’s full field imaging system relies on an indirect X-ray to light conversion optical microscope system. In this setup, X-rays traverse the sample and hit a thin, transparent scintillator screen, thereby generating an image within the visible spectrum. This image is subsequently captured by an sCMOS camera. The microscope adopts a “white beam” geometry, with only the scintillator screen and a right-angle mirror intercepting the X-ray beam. All other optical components, including x5, x10, and x20 objectives, remain outside the beam to shield them from X-ray exposure.
The effective pixel size spans a selection of 1.1 µm, 550 nm or 275 nm, with an initial field of view limited to the natural beam size at the sample position, approximately 1.2 x 1.2 mm². Larger field of view at the moment can be achieved with raster scanning of a sample and further images stitching.
The primary camera utilized in this imaging instrument is the Orca Lightning by Hamamatsu. It has a resolution of 4608 x 2592 pixels (12 Mpx) and has the capability to record up to 120 frames per second at full resolution in a full 16 bits dynamic range. For applications where a higher frame rate is desired, the camera can be configured for a lower dynamic range (12 bits) and a smaller region of interest (ROI). For instance, using a 2000×64 pixel ROI, a readout speed of 8000 frames per second can be achieved. The broadband multilayer monochromator plays a pivotal role in ensuring an ample supply of X-ray photons, facilitating high-speed tomography.
DanMAX’s primary sample goniometer is built around the LAB Motion Systems air-bearing rotary stage RT150U, offering an exceptional level of precision with 20 nm radial and axial error motion. A synchronous slave motor, in conjunction with a rotary union for fluid transmission, is employed to drive this goniometer. The rotary union serves a dual purpose: it not only connects the XY alignment stages atop the rotary stage but also provides essential electrical connections for user-specific sample environments, encompassing small motors, trigger signals, and high-voltage supplies. Moreover, two rotary unions offer the flexibility to deliver high-pressure gases, fluids, or create a vacuum environment as required. The maximum supported weight for both samples and sample environments is 5 kg.