Pb-Qdot Direct Gamma Detectors

描述（由申请人提供）：辐射探测器的一个关键特性是阻止本领，它描述了探测器收集辐射的效率。为了最小化患者剂量，增加阻止本领是有帮助的，因为阻止本领与获得高质量患者图像所需的剂量成反比。阻止本领与探测器材料的有效原子序数密切相关。放射性设备的设计者更喜欢用具有非常高的有效原子序数的材料（例如铅）来构建辐射探测器。不幸的是，大多数具有较高阻止能力的元素不是作为辐射检测器材料的良好候选者，因为电荷（由检测器中的辐射产生）不能容易地从检测器材料中移出。因此，放置在探测器外部的仪器无法测量由探测器材料中的辐射引起的电荷。将电荷从探测器内部转移到外部世界（在那里它可以被测量）的过程称为“电荷传输”。在第一阶段，我们表明，通过将创建高阻止功率的目标与有利的电荷传输的挑战分开，可以切断探测器规格的戈尔迪结。这种分离是通过创建一个矩阵来实现的，在该矩阵中，由高原子序数材料制成的量子点（即，硫化铅）散布在硅基质中。量子点是原子的小集合，其具有与这些原子的体版本不同的电学性质。我们利用硫化铅的高阻止能力特性和量子点的良好电学特性，以高效率将辐射转化为电荷。我们使用硅基质将电荷从量子点有效地传输到硅基质的表面，这样电荷就可以被放大并向外部仪器提供强信号。使用硅作为基质的另一个好处是，我们证明了我们可以构建电路元件（例如，放大器组件）在与辐射检测器相同的材料上。在证明了可行性之后，我们的下一个目标是通过优化探测器质量为产品的商业化做好准备。该项目代表了纳米技术首次成功应用于直接转换辐射探测。它有望减少患者的辐射剂量，降低医疗保健成本。除了诊断放射学市场外，该平台技术还将用于消费者和国防市场的国土安全和广谱监控，并可能与太阳能行业交叉施肥。 公共卫生相关性：该项目代表了纳米技术首次成功应用于直接转换辐射检测。它有望减少收集高质量图像所需的辐射剂量，并降低放射学仪器的成本。除了诊断放射学市场外，该平台技术还将用于国土安全和消费者和国防市场的广谱监控，并可能与太阳能行业交叉施肥。

DESCRIPTION (provided by applicant): A critical property of radiation detectors is stopping power, which describes the efficiency of the detector in collecting radiation. In order to minimize patient dose, it is helpful to increase stopping power, since stopping power is inversely related to the dose required for obtaining high-quality patient images. Stopping power is strongly related to the effective atomic number of the detector material. Designers of radiological devices would prefer to build radiation detectors from materials with very high effective atomic numbers, such as lead. Unfortunately, most elements with higher stopping powers are not good candidates as radiation detector materials, because electrical charges (created by radiation in the detector) cannot be easily moved out of the detector material. As a result, instruments placed outside the detector are unable to measure the charges caused by radiation in the detector material. The process of removing charge from the inside of the detector into the outside world (where that it can be measured) is called "charge transport". In Phase I, we showed that it was possible to cut the Gordian knot of detector specification, by separating the goal of creating high stopping power from the challenge of favorable charge transport. This separation was accomplished by creating a matrix in which quantum dots made of high-atomic- number material (i.e., lead sulfide) were interspersed within a silicon matrix. Quantum dots are small collections of atoms that have different electrical properties than the bulk versions of these atoms. We used the high stopping power property of the lead sulfide, and the favorable electrical properties of the quantum dots, to convert radiation into charge with high efficiency. We used the silicon matrix to transport the charges effectively from the quantum dots to the surface of the silicon matrix, so that the charges could be amplified and provide strong signals to outside instruments. An additional benefit of using silicon as the host matrix was that we showed we could build circuit elements (e.g., amplifier components) on the same material as the radiation detector. Having demonstrated feasibility, our next goal is to ready the product for commercialization by optimizing detector quality. This project represents the first successful application of nanotechnology to direct-conversion radiation detection. It promises to reduce radiation dose to patients and to lower health care costs. In addition to the diagnostic radiology market, the platform technology will be useful for homeland security and broad-spectrum surveillance for the consumer and defense markets, with potential cross-fertilization to the solar power industry. PUBLIC HEALTH RELEVANCE: This project represents the first successful application of nanotechnology to direct-conversion radiation detection. It promises to reduce the radiation doses required to collect high quality images, and to reduce the costs of radiology instrumentation. In addition to the diagnostic radiology market, the platform technology will be useful for homeland security and broad- spectrum surveillance for the consumer and defense markets, with potential cross-fertilization to the solar power industry.