A Novel Ultra-Wideband Gyrotron for DNP-NMR Research

产品说明：我们建议开发一个可调谐振器/腔的25 W，395 GHz的回旋管与超宽带调谐超过6 GHz（1.5%），在整个频带的近恒定功率。回旋管将用于动态核极化（DNP）增强固态和溶液态NMR光谱。使用DNP，NMR实验中固有的小信号强度可以增强几个数量级。这种显着提高的总体灵敏度对于核磁共振光谱学的分析应用以及生物大分子的结构测定非常有益。 目前可用的回旋管，无论是商业的还是在研究实验室中开发的，都具有< 0.1%的有限调谐范围，在较高频率下功率至少有10倍的滚降。因此，具有这种回旋管的系统需要具有昂贵的扫描线圈的NMR磁体，以允许使用不同的偏振剂进行DNP研究，因为在固定的NMR场，用于最高增强的最佳频率可以跨越远超过1%的带宽。具有超宽带调谐能力的回旋管具有几个优点，即，它将（1）消除昂贵的NMR扫描线圈和与在宽范围上扫描场相关联的风险，（2）使标准频率回旋管能够升级当前部署的NMR磁体（没有扫描线圈和稍微不同的场值）在具有DNP升级的场中，而不需要对它们进行再充电，以及（3）允许研究新的偏振剂。 这种新颖的可调谐谐振器/腔将不涉及任何传统的调谐技术，例如机械可移动部件或腔变形，其通常将回旋管的寿命限制为数万小时的操作并且仅允许几百个调谐周期。此外，这种新颖的腔体不需要额外的温孔空间的回旋磁铁，是与目前的DNP回旋架构兼容。因此，这种新颖的概念确保调谐带宽可以增加>15倍，而系统成本的增加可以忽略不计。 在第一阶段，我们将设计，建造和冷测试的新型回旋腔，以证明这一先进的调谐概念。我们还将完成一个可调谐的395 GHz回旋管的设计，在600 MHz的DNP调谐带宽超过6 GHz的至少25 W的功率。在第一阶段的冷态测试中成功验证了创新的调谐概念，这将使第二阶段的原型回旋管的成功开发成为可能。作为该项目的最终成果，我们预计Bridge 12将提供超宽带可调谐陀螺仪，其调谐率大于1.5%，以太赫兹频率为中心，对应于400 MHz（263 GHz）至900 MHz（593 GHz）的NMR光谱仪，用于DNP-NMR光谱学。这将极大地促进利用核磁共振技术确定与人类疾病研究相关的生物大分子的结构。

DESCRIPTION: We propose to develop a tunable resonator/cavity for a 25 W, 395 GHz gyrotron with an ultra-wideband tuning of more than 6 GHz (1.5%) with near-constant power across the band. The gyrotron will be used for Dynamic Nuclear Polarization (DNP) enhanced solid-state and solution-state NMR spectroscopy. With DNP, the inherently small signal intensities in an NMR experiment can be enhanced by several orders of magnitude. This significantly increased overall sensitivity will be highly beneficial for analytical applications o NMR spectroscopy as well as the structure determination of bio-macromolecules. Currently available gyrotrons, either commercial or under development in research labs, have a limited tuning range of < 0.1% with at least a factor of 10 roll-off in power at the higher frequencies. Hence, systems with such gyrotrons need NMR magnets with expensive sweep coils to allow DNP studies with different polarizing agents because at a fixed NMR field, the optimal frequency for highest enhancement can span well over 1% bandwidth. A gyrotron with an ultra-wide band tuning capability has several advantages, namely, it will (1) eliminate the expensive NMR sweep coil and the risk associated with sweeping the field over wide ranges, (2) enable a standard frequency gyrotron for upgrading currently deployed NMR magnets (without sweep coils and slightly different field values) in the field with a DNP upgrade without the need for recharging them and (3) allow investigation of novel polarizing agents. This novel tunable resonator/cavity will not involve any of the traditional tuning techniques such as mechanically movable parts or cavity deformation which, typically limit the lifetime of the gyrotron to a few tens of thousands o hours of operation and allow only a few hundred tuning cycles. Also, this novel cavity does not require additional warm-bore space in the gyrotron magnet and is compatible with current DNP gyrotron architecture. Hence, this novel concept ensures that the tuning bandwidth can be increased by a factor >15 without a negligible increase in system cost. In Phase I, we will design, build and cold test the novel gyrotron cavity to prove this advanced tuning concept. We will also complete the design of a tunable 395 GHz gyrotron with at least 25 W of power over 6 GHz of tuning bandwidth for DNP at 600 MHz. The successful verification of the innovative tuning concept with the cold test in Phase I will enable the successful development of a prototype gyrotron in Phase II. As an ultimate result of this project, we expect Bridge12 to deliver ultra-broad band tunable gyrotrons with >1.5% tuning centered around terahertz frequencies corresponding to NMR spectrometers in the 400 MHz (263 GHz) to 900 MHz (593 GHz) for DNP-NMR spectroscopy. This will greatly accelerate structure determination of bio- macromolecules of relevance to human disease research by NMR techniques.