8BM OPTICS UPGRADE CHARACTERIZATION AND ANALYSIS

8BM 光学升级表征和分析

• 批准号: 7721219
• 负责人: Craig Ogata
• 金额: $ 6.82万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-15 至 2009-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7721219
• 关键词: Back; Computer Retrieval of Information on Scientific Projects Database; Decompression Sickness; Elements; Financial compensation; Funding; Grant; Height; Institution; Lead; Measures; Motion; Motor; Optics; Performance; Range; Reproducibility; Research; Research Personnel; Resources; Solutions; Source; Time; Torque; Travel; United States National Institutes of Health; Water; Yaws; beamline; improved; radius bone structure; size

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. The decision has been made that the re-commissioning and characterization of the 8BM optics would lead to upgrades in the current monochromator. This was to be carried out while the beamline is still at 8-BM so as to reduce the commissioning time after the move to the Sector 24 bending magnet source. Characterization of the optics has identified several elements of the current monochromator that could benefit from upgrades. The first was discovered early on. There were problems in the direct cooling of the first crystal that has led to the possibility of a bulge in the first crystal. A possible solution to this problem is the replacement of the first monochromator crystal by a newer, micro-finned, direct, water-cooled crystal that can be retrofitted into the Oxford Danfysik double crystal monochromator. This new first crystal was installed in December 2005 in conjunction with Oxford Danfysik. The horizontal focusing that is accomplished by the sagittal second crystal has never reached full potential. The difficulty of separating the problems in the first crystal and that of the second has slowed the redesign in the second crystal bender. As a first step in the direction of improving the performance of the second crystal, we have decided to reduce the step size of the motors used to bend the crystal and to install Linear Variable Differential Transformers (LVDT) to measure the displacement directly. The combination of gear reducers and LVDT's will increase the reproducibility of this motion. The added torque from the gear reduced motors will be able to accommodate the smaller radii that are possible after the relocation of the beamline to Sector 24. The new sagittal bender assembly was installed in December 2005 with the first crystal installation. The majority of the early commissioning and characterization has been restricted to overcoming the changes introduced by the installation of a new first crystal and the change in the bending motors of the second crystal. Recurring problems with restrictions in the Yaw motor have been overcome and compensation for the slight changes in the height of the new and re-installed crystals along with a recalibration of the Bragg angle has been accomplished. It is clear that the vertical focusing performance is not satisfactory. The measured flux is similar to the one prior to the upgrade. Further characterization will be performed when the beam comes back in June. Finally, a combination of a 4.7 mrad tilt angle of the mirrors and artificial restrictions in the travel of the second crystal have limited the current energy range of the monochromator to 14.5 keV. This will be resolved after further characterization.

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。 已决定 8BM 光学器件的重新调试和表征将导致当前单色仪的升级。 这是在束线仍处于 8-BM 时执行的，以便减少移动到第 24 区弯曲磁体源后的调试时间。 光学器件的特性确定了当前单色仪的几个可以从升级中受益的元件。 第一个很早就被发现了。 第一个晶体的直接冷却存在问题，导致第一个晶体可能出现凸起。 解决此问题的一个可能的解决方案是用更新的微翅片直接水冷晶体替换第一个单色仪晶体，该晶体可以改装成 Oxford Danfysik 双晶单色仪。 这个新的第一块晶体于 2005 年 12 月与 Oxford Danfysik 联合安装。 由矢状第二晶体实现的水平聚焦从未充分发挥潜力。 区分第一个晶体和第二个晶体中的问题的难度减缓了第二个晶体弯曲机的重新设计。 作为提高第二个晶体性能的第一步，我们决定减少用于弯曲晶体的电机的步长，并安装线性可变差动变压器（LVDT）来直接测量位移。 齿轮减速器和 LVDT 的组合将提高该运动的再现性。 齿轮减速电机增加的扭矩将能够适应光束线重新定位到第 24 区后可能出现的更小的半径。新的矢状弯曲器组件于 2005 年 12 月与第一个晶体安装一起安装。 大部分早期调试和特性描述仅限于克服因安装新的第一晶体和第二晶体弯曲电机的变化而带来的变化。 偏航电机中反复出现的限制问题已经得到解决，并且已经完成了对新的和重新安装的晶体高度的轻微变化的补偿以及布拉格角的重新校准。显然，垂直对焦性能并不令人满意。 测得的通量与升级前相似。 当光束在六月返回时，将进行进一步的表征。 最后，镜子的 4.7 mrad 倾斜角和第二晶体行进中的人为限制相结合，将单色仪的当前能量范围限制为 14.5 keV。 这将在进一步表征后得到解决。