Fig. 1: Instrument design for automated liquid-jet fluorescence dosimetry and sample exposure.

a Block diagram showing system architecture of integrated components operated by a LabVIEW-based controller. The critical components include: high-pressure pump, polished microcapillary jet nozzle, fraction collector (FC), wavelength-specific LED, filters (excitation and emission), dichroic mirror, objective lens, a photomultiplier tube (PMT), data acquisition (DAQ), and imaging camera (Cam). b Computer-aided design of the physical setup at the beamline showing critical modules and components–beam alignment module (BAM), liquid jet module (LJM), fluorescence imaging module (FIM), and laser assisted pre-alignment unit (LAPU). c Top view of the instrument assembly, which is under operation at the beamline 5.3.1 at the Advanced Light Source. Original photograph taken by author S. Gupta. d Side view of the instrument showing how the LAPU assists in focusing the microfocused X-rays on the sample before the Alexa fluorescence data collection by the FIM. e, f Position of microfocused X-ray beam, and fluorescence excitation on the path of a 75 μm liquid jet captured by the BAM at low magnification. Original photograph taken by author S. Gupta. g X-ray beam size was determined from the image analysis using ImageJ (https://imagej.nih.gov/ij). h Camera inline view of fluorescence emitted from the 75 μm sample jet capture by the FIM during automated Alexa DR analysis (Fig. 3). i Camera inline view of a visible image of 75 μm sample jet captured by the FIM during sample exposure.