Activiteit

In rural Bangladesh, the ASQI, adapted for local use, presents a cost-effective approach for child development assessment, exhibiting a moderate correlation with the Bayley-III, making it useful in settings with limited human, time, or financial resources.

A low-cost, Bangladeshi-tailored ASQI tool proves practically applicable in the rural Bangladeshi setting, displaying a moderate correlation with the Bayley-III scale and offering a means to measure child development where human, time, or financial resources are scarce.

Techniques of high-energy resolution core-level spectroscopy, providing element-specific insight into electronic structure around absorption regions, have become critical in examining chemical states, local geometric arrangements, and the nature of chemical bonds. The effectiveness of high-resolution x-ray absorption and x-ray emission spectroscopies, though established, is nonetheless limited by the quantity of emitted photons, constrained solid angle coverage, and the high degree of energy stability and repeatability needed throughout the entire experimental system. Employing flexible HAPG (highly annealed pyrolitic graphite) mosaic crystals, a full-cylindrical x-ray spectrometer offers an effective remedy for the stated issues. Unfortunately, large-area HAPG is usually expensive and not easily obtainable. Instead of the HAPG, we introduce a different approach that uses segmented single crystals (silicon and germanium), each with a unique orientation, to act as the dispersive element. In the energy range of 2-10 keV, the proposed method produced a dramatic improvement in energy resolution, reaching a value of 0.2 eV. The instrument’s capabilities are demonstrated through the presentation of high-pressure x-ray emission and resonant x-ray emission spectra. The new design is notably well-suited to high-resolution spectroscopy experiments at the cutting-edge of fourth-generation synchrotron radiation facilities or free-electron laser systems.

High-resolution photon-counting detector (PCD) computed tomography (CT) imaging is experiencing a rise in use across a range of applications. Technological progress in CT scanning equipment has resulted in the proliferation of varied radiation detection approaches. This project’s focus is on the evaluation of lutetium-yttrium oxyorthosilicate (LYSO) scintillator’s capabilities as a component in PCD CT detectors. In order to achieve this, a mini-CT prototype was meticulously designed and constructed, utilizing pixelated LYSO blocks. The detector’s components include four 10×10 LYSO blocks, arranged linearly, and four position-sensitive photomultiplier tubes that are coupled to them. The prototype’s functionality relies on a point gamma-ray source and a cone-beam collimator assembly. To accommodate in-home data handling, a MATLAB-based data processing package was created. This software manages list-mode data, event positioning, and energy windowing. Investigations were carried out to determine the efficacy of the developed energy-selective LYSOCe detector for use in mini-CT imaging. Crystal identification in all blocks exhibits strong performance, as evidenced by the results, with a maximum peak-to-valley ratio of 348. In conjunction with other results, the findings indicate the detector’s positional sensitivity. Good crystal identification and a 0.71 scatter removal factor, when combined within the 20% energy window, yield optimal performance. Irradiating the detector with a uniform light field led to an observed uniformity of 96%. The mini-CT prototype’s spatial resolution, corrected for a 25x magnification factor, was determined to be 0.09 mm and 0.093 mm in the x- and y-directions, respectively. The pixelated LYSO crystal is determined to be a promising alternative to current detectors, effectively establishing it as the preferred scintillator for high-resolution PCD CT imaging.

A new, compact Thomson parabola ion spectrometer is described, designed to characterize the energy spectra of diverse ion species at multi-MeV energies, sourced from plasmas created by lasers of greater than 10^20 W/cm^2, its operation mirroring the fastest rates available from contemporary and future petawatt-class laser systems. This diagnostic utilizes a fast plastic scintillator (EJ-260), consisting of polyvinyl toluene, and collects emitted light using an optical imaging system, coupled to a thermoelectrically cooled scientific complementary metal-oxide-semiconductor camera. This solution, enabling high-repetition-rate data acquisition, is robust, differing markedly from the increased complications and non-linearity associated with micro-channel plate-based systems. An array of ion energy ranges can be studied with the help of a configurable magnetic assembly, a variable electric field, and a customizable drift-distance mechanism. Our system successfully operated and gathered data from plasmas generated through solid target irradiation, achieving a rate of up to 0.02 Hz; this is purely limited by the targeting apparatus. On-the-fly ion spectral analysis, facilitated by the necessary software, will enable real-time experimental control at multi-Hz repetition rates.

Accurate and swift wind speed and direction measurement is a critical research subject. While current ultrasonic array measurement algorithms rely on spectrum peak identification, the substantial computational cost associated with this process obstructs the broader use and development of ultrasonic array wind parameter measurement technology. This research utilizes an intelligent optimization algorithm coupled with a co-prime arc ultrasonic array to determine wind speed and direction. The methodology bypasses the high computational cost associated with conventional spectrum peak finding algorithms. The propagator method algorithm’s spatial-spectral function is incorporated into the particle swarm optimization algorithm as its fitness function. By transforming the wind parameter estimation problem into a function optimization task, swift and accurate measurements of wind speed and direction become possible. Finally, the artificial bee colony algorithm is applied for the assessment of wind speed and direction, effectively diminishing the calculation intensity of the wind parameter measurement. Comparative experiments and design simulations confirm the performance and speed advantages of the proposed methodology, culminating in a 90% reduction in time complexity. Hardware experiments serve to validate the practicality of the proposed method.

Accurate current readings are crucial for understanding the polydispersity in the beam of charged particles that arise from an electrospray device. Secondary species emission (SSE), caused by high-velocity impacts of nanodroplets or molecular ions on surfaces, substantially affects the precision of current measurements. Positive and negative species are components of SSE; therefore, plasma diagnostic techniques alone are insufficient for mitigating measurement uncertainty. Primary species, positive SSE, and negative SSE’s current contributions are differentiated by the presented probe and analysis methodologies. The separation of each contribution results in positive and negative SSE yield metrics and corrected current readings, mirroring the true primary current. This paper explores the sources of uncertainty in probe design, alongside the corresponding mitigation strategies. The probe and analysis techniques are shown applied to an ionic liquid electrospray in droplet emission mode to obtain an angular distribution of positive and negative SSE yields for the ionic liquid electrospray.

Laser light scattering systems utilizing volume Bragg grating (VBG) filters, functioning as spectral and angular filters, frequently serve as point measurement tools, offering spatial resolutions as low as a few hundred micrometers, determined by the beam waist. This study demonstrates the utility of VBG filters for spatially-resolved measurements, achieving a resolution of several millimeters across a few millimeters along the beam’s propagation direction. The angular acceptance criteria of the filter dictate the rejection ring, which is derived analytically, and its application in 1D laser line rejection is detailed. pcna signal For the cases presented, specifically for a focused probe beam waist with a diameter of 150 meters, the rejection ring permits resolution up to several millimeters along the beam propagation axis for a one-dimensional measurement, and this is further controllable. Further, techniques to amplify the measurable region are demonstrated and introduced using a collimation lens with a distinct focal length or by employing multiple VBG filters. Minimizing scattering signal loss in the latter scenario avoids compromising the solid angle. Employing multiple VBGs expands the measurable region along the beam axis, a departure from conventional multiple filter applications, which are designed to reduce elastic interferences. 1D rotational Raman and Thomson scattering measurements, conducted on pulsed and DC discharges, serve to validate this method. Compactness, straightforward implementation, high performance, and adaptable design define the system’s capacity to handle various experimental scenarios.

With sub-micrometer spatial resolution, angle-resolved photoemission spectroscopy (ARPES) has established itself as an essential tool for exploring quantum materials. The key to achieving sub-micrometer or even nanometer-scale spatial resolution is the concentration of the incident light beam, usually originating from synchrotron radiation, using x-ray optics, including zone plates and ellipsoidal capillary mirrors. Our team recently achieved the development of a laser-based spin-resolved ARPES technique and named it LMS-ARPES. Frequency doubling of a 355 nm beam, facilitated by a KBBF crystal, generates a 177 nm laser beam, subsequently focused by an optical lens with a focal length of approximately 16 mm. By employing diverse methodologies for assessing the focused spot size, in conjunction with spatial-scanning photoemission measurements, we verify the system’s sub-micron spatial resolution.