MRI: Development of a High Pressure Laser Heating System

0923166WrobelU.技术摘要：由于技术原因，以及物理学、材料科学、微物理学和化学的基础研究，正在探索将高压和高温同时应用于材料。激光加热的金刚石压砧是在实验室中实现这些极端条件的一种方法。 目前的激光加热技术使用CW红外激光器来照射在金刚石压砧单元内加压的样品。 该技术仅限于~ 7，000 K的温度;限制由激光器的功率施加。 我们建议开发一个紫外脉冲激光加热系统，追求激光加热的样品，是在高压下，而在金刚石砧单元。 所提出的系统将允许样品经受高压和大于20，000 K的温度。 使用紫外激光器将达到的显著更高的温度是由于脉冲系统中可用的更大功率的组合，并且大多数材料在紫外线中的吸收系数高于红外线。 样品温度和温度演变将通过使用门控CCD测量发射的黑体辐射来确定。 最初的激光加热系统将用于合成新的氮化物化合物，预计将具有独特的性能，如高硬度的情况下，WN 2和？-C3N4拟议中的系统，其三倍的可达温度比目前的技术，也将允许前所未有的进展，熔化研究，相图和状态方程。 这将影响物理学、材料科学、化学和地球科学领域。该仪器的建造和研究将为研究生和本科生提供先进仪器和科学研究方面的培训，并将产生广泛的社会影响。Layman摘要：高压和高温的同时应用已被证明会影响许多材料的性能。 最著名的例子之一是石墨向金刚石的转化。 这发生在地球内部，产生天然金刚石，从1955年开始，研究人员已经能够通过在实验室中创造必要的高压高温条件从石墨中生产金刚石。 除了有利的结构变化（如石墨到金刚石）外，高压和高温也会改变材料的化学性质。 例如，可以使通常不结合的元素进行联合收割机，产生新的和潜在有用的化合物。 拟议中的仪器将使人们有可能研究在高达一百万个大气压的压力下放置的材料，同时温度比传统方法高出三倍。 允许如此高温的主要创新是使用紫外光的短激光脉冲，该脉冲将被压缩材料吸收并加热它们。在拟议的仪器完成后，最初的实验将是合成新的有用的化合物。 这项技术将被更广泛地用于确定各种材料在极端条件下的变化，这将推动物理学、材料科学、化学和地球科学领域的发展。 建设和研究，拟议的仪器将培养研究生和本科生在先进的仪器，科学研究，并将产生广泛的社会影响。

0923166WrobelU. of Missouri-Kansas CityTechnical Summary: The simultaneous application of high pressures and temperatures to materials is being explored for technological reasons, and for basic research in physics, materials science, geophysics and chemistry. A laser heated diamond anvil cell is one way to achieve these extreme conditions in the laboratory. Current laser heating technology uses CW infrared lasers to irradiate samples that are pressurized inside of a diamond anvil cell. This technology is limited to temperatures of ~ 7,000 K; the limitation being imposed by the power of the lasers. We propose to develop a UV pulsed laser heating system to pursue laser heating of samples that are under high pressures while in a diamond anvil cell. The proposed system will allow for samples to be subjected to high pressures, and temperatures of greater than 20,000 K. The substantially higher temperature that will be reached with the UV laser is due to the combination of greater power available in a pulsed system, and that most materials have higher absorption coefficients in the UV than in the infrared. Sample temperatures and the temperature evolution will be determined by using a gated CCD to measure the emitted blackbody radiation. Initially the laser heating system will be used for synthesis of new nitride compounds which are expected to have unique properties, such as high hardness for the cases of WN2 and ?Ò-C3N4. The proposed system, with its three-fold increase in accessible temperatures over current technology will also allow unprecedented advances in melting studies, phase diagrams, and equations of state. This will impact the fields of physics, materials science, chemistry and geoscience. Construction of, and research with, the proposed instrument will train graduate and undergraduate students in advanced instrumentation, scientific research, and will have broad societal impact.Layman Summary: The simultaneous application of high pressures and high temperatures, has been shown to impact the properties of many materials. One of the best known examples of this is the conversion of graphite to diamond. This occurs inside the earth, producing natural diamonds, and beginning in 1955 researchers have been able to produce diamond from graphite by creating the necessary high pressure-high temperature conditions in the lab. In addition to advantageous structural changes (such as graphite to diamond), it has been shown that high pressures and high temperatures also change the chemistry of materials. For example, elements that do not normally bond can be made to combine, resulting in novel and potentially useful compounds. The proposed instrument will make it possible to study materials placed under pressures of up to one million atmospheres while at temperatures three times greater than has been achieved with conventional methods. The main innovation that will allow for such high temperatures is the use of short laser pulses of ultraviolet light which will be absorbed by the compressed materials and heat them. Upon completion of the proposed instrument, the initial experiments will be to synthesize new, useful compounds. The proposed technology will be used more broadly to determine how a variety of materials change under extreme conditions, which will advance the fields of physics, materials science, chemistry and geoscience. Construction of, and research with, the proposed instrument will train graduate and undergraduate students in advanced instrumentation, scientific research and will have broad societal impact.