X-Ray Detectors for Synchrotron-Based Structural Biology

用于基于同步加速器的结构生物学的 X 射线探测器

• 批准号: 6643800
• 负责人: RONALD C HAMLIN
• 金额: $ 184.08万
• 依托单位: AREA DETECTOR SYSTEMS CORPORATION
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-03-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6643800
• 关键词: X ray crystallography; biomedical equipment development; data collection; digital imaging; electrical potential; method development; radiation detector; structural biology; synchrotrons; time resolved data

DESCRIPTION (provided by applicant): Development is proposed of an x-ray Pixel Array Detector (PAD) consisting approximately of 2,000 x 2,000 pixels to enhance macromolecular crystallographic data collection at synchrotron sources. A PAD consists of an x-ray sensing integrated circuit layer bonded to a pixel electronics layer such that each pixel has its own processing electronics. PADs promise to reduce data collection time by up to a factor of 40 relative to existing detectors while improving data quality. They will have specific capability to: 1) Collect a set of monochromatic data (90 degree rotation) in 18 seconds using the standard oscillation method (0.5 degrees per frame, with exposure time of 100 ms per frame) 2) Collect a set of fine-slice data in 90 seconds with a rotation of 0.05 degrees per frame and with an exposure of 50 ms per frame 3) Collect frames at microsecond exposure time for time-resolved protein Laue diffraction. Research during Phase I of this proposal was successful in identifying a mixed-mode analog/digital pixel architecture best suited for the crystallographic application, as well as demonstrating ways of resolving radiation damage concerns. The input signal is analog integrated onto a capacitor, C(int), by a charge to voltage converter in the charge integrator stage using a structure very similar to the one in the existing APAD designs. The voltage on the capacitor is constantly compared to an external reference voltage, V(ref), via a voltage comparator in the threshold detector stage. When the integrated voltage level reaches the reference voltage, a bit is generated and added into an in-pixel digital counter. The threshold detector then also resets the integration capacitor in the charge integrator stage. Thus, each analog cycle of filling C(int) results in an additional digital "count" in the high-order word stored in the in-pixel digital counter. At the end of the exposure frame, the voltage level remaining on C(int) is digitized, if desired, by an analog-to-digital converter (ADC) at the end of each row of pixels. This digitized value is thus the low-order digital word of the exposure Phase II will involve finalization of the specific pixel layout, fabrication of suitably large-area integrated circuits, assembly and application testing of a full-scale PAD.

描述（由申请人提供）：提出开发一种由大约2，000 x 2，000像素组成的X射线像素阵列探测器（PAD），以增强同步加速器源处的大分子晶体学数据收集。PAD由结合到像素电子器件层的X射线感测集成电路层组成，使得每个像素具有其自己的处理电子器件。PAD有望将数据收集时间减少到现有探测器的40倍，同时提高数据质量。他们将具备以下具体能力：1）收集一组单色数据（90度旋转）在18秒内使用标准振荡方法（每帧0.5度，曝光时间为每帧100 ms）2）在90秒内收集一组精细切片数据，每帧旋转0.05度，曝光时间为每帧50 ms 3）以微秒曝光时间收集帧，用于时间分辨蛋白质劳厄衍射。 该提案第一阶段的研究成功地确定了最适合晶体学应用的混合模式模拟/数字像素架构，并展示了解决辐射损伤问题的方法。输入信号通过电荷积分器级中的电荷-电压转换器模拟积分到电容器C（int）上，电荷积分器级中的电荷-电压转换器使用与现有APAD设计中的结构非常相似的结构。电容器上的电压通过阈值检测器级中的电压比较器不断地与外部参考电压V（ref）进行比较。当积分电压电平达到参考电压时，产生一个位并将其添加到像素内数字计数器中。然后，阈值检测器还复位电荷积分器级中的积分电容器。因此，填充C（int）的每个模拟周期导致存储在像素内数字计数器中的高阶字中的附加数字“计数”。 在曝光帧结束时，如果需要，则通过每行像素结束处的模数转换器（ADC）将C（int）上剩余的电压电平数字化。因此，该数字化值是曝光的低阶数字字。第二阶段将涉及特定像素布局的最终确定、适当大面积集成电路的制造、全尺寸PAD的组装和应用测试。