Kaplanstafford9767

5. In addition to the aspects mentioned above, a possibility to manipulate the aggregation downstream of the reactor is to be presented as well. We found that applying electrical charges to the aerosol particles (in opposite polarity) can significantly foster aggregation.A single crystal chemical vapor deposition diamond-based microdosimeter prototype featuring an array of micro-sensitive volumes (μSVs) and surrounded by a so-called guard ring (GR) electrode has been fabricated using various microfabrication techniques available at Diamond Sensors Laboratory of CEA, Saclay. find more The GR microdosimeter was irradiated by a raster scanning method with 2 MeV proton microbeams. The charge transport properties of the GR sensor were determined with sub-micron spatial resolution by measuring the charge collection efficiency (CCE), the μSV geometry, and the pulse-height spectra. The response of the microdosimeter showed a well-defined and homogeneously active μSV. Appropriate biasing of the μSV structures led toward a full CCE for protons with lineal energies of ∼46 keV/μm. This shows the GR microdosimeter's great potential for applications in microdosimetry in clinical beam conditions.We have designed and prototyped the process steps for the batch production of large-area micro-channel-plate photomultipliers (MCP-PMT) using the "air-transfer" assembly process developed with single LAPPDTM modules. Results are presented addressing the challenges of designing a robust package that can transmit large numbers of electrical signals for pad or strip readout from inside the vacuum tube and of hermetically sealing the large-perimeter window-body interface. We have also synthesized a photocathode in a large-area low-aspect-ratio volume and have shown that the micro-channel plates recover their functionality after cathode synthesis. These steps inform a design for a multi-module batch facility employing dual nested low-vacuum and ultra-high-vacuum systems in a small-footprint. The facility design provides full access to multiple MCP-PMT modules prior to hermetic pinch-off for leak-checking and real-time photocathode optimization.High temperature solids and liquids are becoming increasingly important in next-generation energy and manufacturing systems that seek higher efficiencies and lower emissions. Accurate measurements of thermal conductivity at high temperatures are required for the modeling and design of these systems, but commonly employed time-domain measurements can have errors from convection, corrosion, and ambient temperature fluctuations. Here, we describe the development of a frequency-domain hot-wire technique capable of accurately measuring the thermal conductivity of solid and molten compounds from room temperature up to 800 °C. By operating in the frequency-domain, we can lock into the harmonic thermal response of the material and reject the influence of ambient temperature fluctuations, and we can keep the probed volume below 1 µl to minimize convection. The design of the microfabricated hot-wire sensor, electrical systems, and insulating wire coating to protect against corrosion is covered in detail. Furthermore, we discuss the development of a full three-dimensional multilayer thermal model that accounts for both radial conduction into the sample and axial conduction along the wire and the effect of wire coatings. The 3D, multilayer model facilitates the measurement of small sample volumes important for material development. A sensitivity analysis and an error propagation calculation of the frequency-domain thermal model are performed to demonstrate what factors are most important for thermal conductivity measurements. Finally, we show thermal conductivity measurements including model data fitting on gas (argon), solid (sulfur), and molten substances over a range of temperatures.We present a novel and thorough simulation technique to understand image charge generated from charged particles on a printed-circuit-board detector. We also describe a custom differential amplifier to exploit the near-differential input to improve the signal-to-noise-ratio of the measured image charge. The simulation technique analyzes how different parameters such as the position, velocity, and charge magnitude of a particle affect the image charge and the amplifier output. It also enables the designer to directly import signals into circuit simulation software to analyze the full signal conversion process from the image charge to the amplifier output. A novel measurement setup using a Venturi vacuum system injects single charged particles (with diameters in the 100 s of microns range) through a PCB detector containing patterned electrodes to verify our simulation technique and amplifier performance. The measured differential amplifier presented here exhibits a gain of 7.96 µV/e- and a single-pass noise floor of 1030 e-, which is about 13× lower than that of the referenced commercial amplifier. The amplifier also has the capability to reach a single-pass noise floor lower than 140 e-, which has been shown in Cadence simulation.We report a novel experimental technique to investigate ultrafast dynamics in photoexcited molecules by probing the 3rd-order nonlinear optical susceptibility. A non-collinear 3-pulse scheme is developed to probe the ultrafast dynamics of excited electronic states using the optical Kerr effect. Optical homodyne and optical heterodyne detections are demonstrated to measure the 3rd-order nonlinear optical response for the S1 excited state of liquid nitrobenzene, which is populated by 2-photon absorption of a 780 nm 40 fs excitation pulse.A new variant of the Laser-Induced Pressure-Pulse (LIPP) method for repeatable, time-resolved space-charge profile measurements is proposed and demonstrated. Automated deposition of a fresh laser-target film before each illumination leads to good repeatability of the LIPP and thus allows for the detection of time-resolved changes in the space-charge distribution over many hours. We describe and discuss the experimental setup and its features, compare the repeatability of the LIPP measurements on the same sample without and with re-preparation of the test cell, and present the time-resolved evolution of the space-charge profile in a two-layer arrangement of a silicone-grease and a silicone-elastomer film as an example. Finally, the temperature dependence of the space-charge evolution during polarization under high voltage and during depolarization in short circuit is shown. Possible uses and future developments of the new LIPP approach are also discussed.