MICRODIFFRACTION AT THE NE-CAT BEAMLINES

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。对于配备用于对小于20-30微米的晶体进行衍射实验的同步加速器光束线的需求不断增加。Ne-CAT？S一期束线已经证明了束线组件的稳定性，可以为常规尺寸晶体的结晶学实验提供稳定、聚焦的X射线束。I相光束线不是为显微衍射量身定做的。然而，NE-CAT用户经常携带小晶体，最大尺寸小于30微米。其中一些晶体会产生衍射数据/结构，而另一些则不会。我们预计，很快将有越来越多的用户常规地将这种较小的晶体带到NE-CAT光束线上。通过优化光束线组件，可以极大地提高对较小晶体的这种实验的成功，从而a)可以容易地观察到较小的样品，b)可以制作与样品大小相匹配的小光束，以及c)可以减少背地散射。考虑到这些事实，我们使用APS设计的不确定度球大大小于2微米的测角仪，开发了高倍率同轴样品成像仪，并升级了光束光学系统，以提供干净的微焦点，从而评估了室内微衍射能力的发展。虽然这是可行的，但这可能是一项耗时的工作，因为我们的技术人员正专注于第二期梁线的建设。因此，为了在尽可能早的时间尺度上向NE-CAT用户提供微衍射能力，我们决定购买一台商业设备。我们已经授予Accel购买由Maatel制造的MD2微衍射仪。这种微型衍射仪的设计源自欧洲分子生物学实验室(EMBL)，其单元正成功地用于ESRF和SLS。有了这种微衍射仪，我们希望能够常规地研究尺寸为几微米的晶体，使用为类似尺寸量身定做的光束，以减少散射污染和背景。我们将是第一个在美国运营的这样的部门。预计在2006年9月交付，也就是APS预定的维护停运期。MD2最初将安装在二期梁线上，以便梁线和MD2可以同时投入使用，而不会影响一期用户程序。我们希望在2006年末提供MD2的早期用户时间。

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. There is increasing demand for synchrotron beam lines equipped for carrying out diffraction experiments with crystals smaller than 20-30 microns. NE-CAT¿s phase I beam line has demonstrated the stability of the beam line components to provide stable, focused X-ray beam for crystallographic experiments with routine size crystals. The phase I beam line is not custom-made for microdiffraction. However, often NE-CAT users bring small crystals, with maximum dimension less than 30 microns. Some of these crystals result in diffraction data/structure and some do not. We foresee that soon an increasing number of our users will be routinely bringing such smaller crystals to the NE-CAT beam lines. The success of such experiments with smaller crystals could be greatly enhanced by optimizing the beam line components so that, a) smaller samples could be easily visualized, b) small beam could be crafted to match the size of sample and c) back ground scatter could be reduced. With these facts in mind, we have assessed development of a microdiffraction capability in house using a APS designed goniometer with a sphere of uncertainty of substantially less than 2 microns, developing a high-magnification co-axial sample imager, and upgrading the beam optics to provide a clean micro focus. Though it is feasible, it could be time consuming undertaking as our technical staff is focusing on construction of Phase II beam line. Therefore, in order to provide microdiffraction capability to NE-CAT users on the earliest time scale possible, we have decided to purchase a unit commercially. We have made an award to ACCEL to acquire the MD2 microdiffractometer manufactured by Maatel. The design for this microdiffractometer originates from the European Molecular Biology Laboratory (EMBL), units of which are being successfully used at the ESRF and SLS. With this microdiffractometer, we expect to be able to routinely study crystals with dimensions of a few microns using beams tailored to similar dimensions in order to reduce scattering contamination and backgrounds. Ours will be the first such unit operating in the US. Delivery is expected during September 2006, the scheduled APS maintenance shut down period. The MD2 will be initially installed on the Phase II beam line so that both the beam line and the MD2 can be commissioned at the same time, not impacting the Phase I user program. We expect to offer early user time on MD2 during late 2006.