Scintillator-based Timepix3 detector for neutron spin-echo techniques using intensity modulation.

A scintillator-based Timepix3 (TPX3) detector was developed to resolve the high-frequency modulation of a neutron beam in both spatial and temporal domains, as required for neutron spin-echo experiments. In this system, light from a scintillator is manipulated with an optical lens and is intensified using an image intensifier, making it detectable with the TPX3 chip. Two different scintillators, namely, 6LiF:ZnS(Ag) and 6LiI:Eu, were investigated to achieve the high resolution needed for spin-echo modulated small-angle neutron scattering (SEMSANS) and modulation of intensity with zero effort (MIEZE). The methodology for conducting event-mode analysis is described, including the optimization of clustering parameters for both scintillators. The detector with both scintillators was characterized with respect to detection efficiency, spatial resolution, count rate, uniformity, and γ-sensitivity. The 6LiF:ZnS(Ag) scintillator-based detector achieved a spatial resolution of 200 µm and a count rate capability of 1.1 × 105 cps, while the 6LiI:Eu scintillator-based detector demonstrated a spatial resolution of 250 µm and a count rate capability exceeding 2.9 × 105 cps. Furthermore, high-frequency intensity modulations in both spatial and temporal domains were successfully observed, confirming the suitability of this detector for SEMSANS and MIEZE techniques, respectively.

Design, characterization, and performance of a hard x-ray transmission microscope at the National Synchrotron Light Source II 18-ID beamline.

A transmission X-ray microscope has been designed and commissioned at the 18-ID Full-field X-ray Imaging beamline at the National Synchrotron Light Source II. This instrument operates in the 5-11 keV range, and, with the current set of optics, is capable of 30 nm spatial resolution imaging, with a field of view of about 40 µm. For absorption contrast, the minimum exposure time for a single projection image is about 20 ms and an entire 3D tomography data set can be acquired in under 1 min. The system enables tomographic reconstructions with sub-50 nm spatial resolution without the use of markers on the sample or corrections for rotation run-outs.

Using sound pulses to solve the crystal-harvesting bottleneck.

Crystal harvesting has proven to be difficult to automate and remains the rate-limiting step for many structure-determination and high-throughput screening projects. This has resulted in crystals being prepared more rapidly than they can be harvested for X-ray data collection. Fourth-generation synchrotrons will support extraordinarily rapid rates of data acquisition, putting further pressure on the crystal-harvesting bottleneck. Here, a simple solution is reported in which crystals can be acoustically harvested from slightly modified MiTeGen In Situ-1 crystallization plates. This technique uses an acoustic pulse to eject each crystal out of its crystallization well, through a short air column and onto a micro-mesh (improving on previous work, which required separately grown crystals to be transferred before harvesting). Crystals can be individually harvested or can be serially combined with a chemical library such as a fragment library.