95 GHZ SPECTROMETER PULSE TIMING SYSTEM UPGRADE

95 GHZ 光谱仪脉冲计时系统升级

• 批准号: 8172182
• 负责人: CURT R DUNNAM
• 金额: $ 1.1万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8172182
• 关键词: Address; Computer Retrieval of Information on Scientific Projects Database; Computer software; Funding; Generations; Grant; Institution; Linux; Minor; Modification; Operating System; Output; Pattern; Physiologic pulse; Process; Relative (related person); Research; Research Personnel; Resolution; Resources; Source; System; Technology; Time; Uncertainty; United States National Institutes of Health; Width; Work; base; instrument; millimeter; research study

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. A centerpiece instrument at ACERT is our millimeter-wave c.w./pulse spectrometer operating at 95GHz. In pulse mode, this instrument is capable of producing precisely-defined 1.2KW r.f. pulses down to 2ns widths and 1 ns absolute resolution. In its current configuration, the spectrometer utilizes a PulseBlaster ESR-300 (SpinCore Technologies, Inc.) with a proprietary high resolution broadside-parallel to time-serial converter card (ACERT-PBHR) to create an interim timing system producing r.f. control pulses with 1ns resolution. However, there are several undesirable operational tradeoffs which have been necessarily accepted in originally adapting the existing commercial timing card to our HFHF use. These drawbacks include the relatively coarse (3.2 ns) relative timing between control channels and the undesirably long delay time (16 ns) needed between programmable transitions on any one timing line. These limitations add unnecessary complexity to the pattern generation software and, to a minor extent, constrain the timing patterns actually available for the experiment. There is also an approx. 300 ps peak-to-peak timing uncertainty in the high resolution channel, which becomes consequential once other deadtime contributing factors in the spectrometer have been corrected. We are in the process of addressing these issues with a spectrometer control system upgrade incorporating a high resolution timing card (Chase Scientific DWG-1000) that outputs 12 channels with intrinsic 1ns resolution. Because the spectrometer operating system is Linux based, and suitable drivers are not yet available, some additional work will be required to incorporate the timing upgrade hardware. Presently, we are completing EIK h.v. modulator modifications which will result in a significant reduction of deadtime with the existing timing system still in place. Soon after completion and qualification of the modulator upgrades with the present timing hardware, we expect to install the new Chase Scientific timing card and modify the spectrometer control software as necessary to fully utilize its capability for additional deadtime reduction.

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。子项目和 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以在其他 CRISP 条目中表示。列出的机构是 对于中心来说，它不一定是研究者的机构。 ACERT 的核心仪器是我们的毫米波连续波/脉冲光谱仪，工作频率为 95GHz。在脉冲模式下，该仪器能够产生精确定义的 1.2KW 射频。脉冲宽度低至 2ns，绝对分辨率为 1ns。在当前配置中，光谱仪利用 PulseBlaster ESR-300 (SpinCore Technologies, Inc.) 和专有的高分辨率宽边并行时间串行转换器卡 (ACERT-PBHR) 来创建临时定时系统，产生射频信号。控制脉冲分辨率为1ns。然而，在最初使现有的商业定时卡适应我们的 HFHF 使用时，存在一些不希望的操作权衡，这些权衡是必须接受的。这些缺点包括控制通道之间的相对时序相对粗糙（3.2 ns），以及任何一根时序线上的可编程转换之间所需的不合需要的长延迟时间（16 ns）。这些限制给模式生成软件增加了不必要的复杂性，并且在较小程度上限制了实验实际可用的计时模式。还有一个大约。高分辨率通道中存在 300 ps 峰峰值定时不确定性，一旦校正了光谱仪中的其他死区时间影响因素，该不确定性就会变得严重。 我们正在通过光谱仪控制系统升级来解决这些问题，该系统升级包含高分辨率定时卡（Chase Scientific DWG-1000），该卡输出具有固有 1ns 分辨率的 12 个通道。由于光谱仪操作系统是基于Linux的，并且还没有合适的驱动程序，因此需要一些额外的工作来合并定时升级硬件。 目前，我们正在完成 EIK h.v.调制器的修改将导致在现有计时系统仍然存在的情况下显着减少死区时间。在完成当前定时硬件的调制器升级并鉴定后不久，我们预计将安装新的 Chase Scientific 定时卡，并根据需要修改光谱仪控制软件，以充分利用其额外减少死区时间的功能。