MRI: Development of a High Pressure Laser Heating System

0923166 WrobelU.密苏里州-堪萨斯市技术概述：出于技术原因以及物理、材料科学、地球物理和化学的基础研究，正在探索将高压和高温同时应用于材料。激光加热的钻石压腔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连续波红外激光照射样品，这些样品被加压在钻石顶头单元内。这项技术被限制在~7000K的温度；这一限制是由激光器的功率施加的。我们建议开发一种紫外光脉冲激光加热系统，用于对在金刚石顶压室中处于高压下的样品进行激光加热。建议的系统将允许样品经受高于20,000 K的高压和温度。使用UV激光将达到显著更高的温度是由于脉冲系统中可获得的更大功率的组合，以及大多数材料在UV中的吸收系数高于在红外中的吸收系数。样品的温度和温度的演变将通过使用选通的CCD测量发射的黑体辐射来确定。最初，激光加热系统将用于合成新的氮化物化合物，这些化合物有望具有独特的性能，如WN_2和-C_3N_4的高硬度。拟议中的系统，其可到达的温度比目前的技术提高了三倍，也将使熔化研究、相图和状态方程取得前所未有的进展。这将对物理、材料科学、化学和地球科学领域产生影响。建议的仪器的建造和研究将培训研究生和本科生先进的仪器设备和科学研究，并将产生广泛的社会影响。莱曼摘要：高压和高温的同时应用，已被证明影响许多材料的性能。最著名的例子之一就是将石墨转化为钻石。这发生在地球内部，产生天然钻石，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-高温条件来从石墨中生产钻石。除了有利的结构变化(如石墨向金刚石)外，已有研究表明，高压和高温也会改变材料的化学成分。例如，通常不成键的元素可以组合在一起，产生新的和潜在有用的化合物。拟议中的仪器将使研究置于高达100万大气压的压力下的材料成为可能，而温度却比传统方法高出三倍。允许如此高温的主要创新是使用短激光脉冲的紫外光，这些紫外光将被压缩的材料吸收并加热。在拟议的仪器完成后，初步实验将是合成新的有用的化合物。这项拟议的技术将被更广泛地用于确定各种材料在极端条件下如何变化，这将推动物理、材料科学、化学和地球科学领域的发展。该仪器的建造和研究将对研究生和本科生进行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。

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.