Nanofocusing optics for synchrotron radiation instrumentation

该提案要求人力和设施来开发一种新型x射线透镜，这将对纳米级材料的研究产生重大影响。第三代同步加速器源所取得的前所未有的辉煌为纳米尺度材料的研究开辟了新的机会。它将对包括环境科学、催化和生物学在内的广泛研究领域产生巨大影响。开发改进光源的关键是开发新型光学元件，使窄光束聚焦而不损失其亮度和相干性。掠掠角反射镜的应用非常广泛，但由于掠掠角很小（毫弧度），光子光束对斜面误差和粗糙度特别敏感。超越当前最先进技术的发展是有限和昂贵的。人们提出了依靠折射和衍射的新装置。这些包括复合折射透镜（CRL’s）和kinoform透镜。CRL是通过用非常坚硬的抛物工具压制材料，然后将几个透镜组装在一起以达到所选能量的所需焦点来获得的。铝和铍CRL通常用于其他同步加速器，并且使用Be CRL获得的良好横向分辨率使它们甚至适合成像。用新型的折射率微晶硅平面透镜可以得到几十纳米的聚焦光斑，其形状比简单的压铝或be透镜更精确。Diamond的光学小组和这个项目的合作者旨在提高和扩大英国在纳米聚焦透镜设计和制造方面的专业知识，并以比镜子更低的成本常规提供微聚焦透镜。该小组利用仪器中心的一笔适度拨款，制造并成功测试了硅平面低吸收kinoform透镜。在光子能量为12kev的情况下，获得了微聚焦光斑。数据显示短聚焦尾和缺乏背景。还有很多改进的空间，我们相信，如果这个项目成功，英国同步加速器用户将有机会获得最好的在线聚焦光学。在此建议下，我们请求资源以提高微聚焦透镜的接受度并实现纳米聚焦。除了硅单晶外，我们希望使用CVD金刚石、锗和镍等其他透镜材料。事实上，需要不同的材料来覆盖较大的光子能量范围。此外，CVD金刚石在功率负载和低吸收方面具有最佳性能。这些透镜在光束线上的实际应用需要特殊的安排。单平面折射透镜产生线焦点：为了产生点焦点，两个晶圆必须保持在正确的位置和相互方向，因此必须设想特殊的支架和机动平台。监测和校准仪器与纳米精度将开发和测试同步加速器光束线。最后，我们希望回复董事会的要求，即“完整的提案应包括有多少用户将从这项开发中受益，以及新设备与其他地方正在开发的类似设备有何不同，例如在ESRF”。我们在支持案例中强调，ESRF已经开发出基于反射镜和多层的聚焦和准直光学系统。这里提出的折射光学已经由其他实验室（亚琛大学，保罗谢勒研究所）开发，只在ESRF进行了测试。纳米聚焦透镜已被证明，但尚未得到充分利用。50纳米的光束是在非常少的光束线的特殊条件下实现的。这些实验室制造的镜片将在很长一段时间内无法向英国用户提供，因为它们是不可购买的（除了be和Al镜片，它们不是纳米聚焦设备）。我们的目标是每天为50%的英国用户提供这些服务。

This proposal requests manpower and facilities to develop a novel type of X-ray lens that will have a major impact in the study of nano-scale materials. The unprecedented brilliance achieved by 3rd generation synchrotron sources has opened up new opportunities for the study of materials at the nanometre scale. It will have a huge impact on a wide area of research including environmental science, catalysis and biology. The key to the exploitation of the improved sources is the development of novel optics that focus the narrow beams without loss of their brilliance and coherence. Grazing angle mirrors are widely used, but because of the grazing angle (few milliradians) the photon beam is particularly sensitive to slope errors, and roughness. Developments beyond current state-of-the-art are limited and expensive. New devices have been proposed that rely on refraction and diffraction. These include compound refractive lenses (CRL's) and kinoform lenses. CRL's are obtained by pressing the material with very hard parabolic tools, and then assembling several lenses together to reach the desired focus at the chosen energy. Aluminium and beryllium CRL's are routinely used in other synchrotrons and the good lateral resolution obtained with Be CRL's makes them even suitable for imaging. Focused spots of few tens of nanometers have been demonstrated with new refractive micro fabricated silicon planar lens, which can be more accurate in shape than simple pressed Al or Be lenses. The Optics Group at Diamond and the collaborators in this project aim at improving and enlarging the UK know-how on design and fabrication of nanofocusing lenses and routinely provide microfocusing lenses at lower cost than mirrors. Silicon planar low absorption kinoform lenses have been fabricated and successfully tested by the group, using a modest grant from the Centre for Instrumentation. A microfocused spot was obtained with these lenses at a photon energy of 12 keV. The data show short focus tails and absence of background. There is much scope for improvement and we believe that if this project is successful, UK synchrotron users will have access to the best in-line focusing optics. With this proposal we request resources for improving acceptance of the microfocus lenses and to achieve nanofocusing. In addition to silicon single crystal, we wish to use other lens materials like CVD diamond, germanium and nickel. Different materials are infact needed to cover a large photon energy range. CVD diamond, moreover, has the best performance in terms of power load and low absorption. Practical exploitation of these lenses in beamlines will require special arrangements. A single planar refractive lens produces a line focus: in order to produce a point focus two wafers have to be held at the right positions and mutual orientation, therefore special holders and motorised stages have to be envisaged. Monitoring and alignment of instrumentation with nanometre precision will be developed and tested on synchrotron beamlines. Finally, we wish to reply to the board request that 'The full proposal should include how many users will benefit from this development and how the new equipment differs from similar equipment being developed elsewhere e.g. at the ESRF'. We highlight in the support case that the ESRF has developed focusing and collimating optics based on mirrors and multilayers. The refractive optics proposed here have been developed by other laboratories (Aachen University, Paul Scherrer Institute) and only tested at the ESRF. Nanofocusing lenses have been demonstrated but not brought to full exploitation. Beams of 50 nm are achieved under special conditions at very few beamlines. Lenses fabricated in these laboratories will not be available to UK users for a long period because they are not for purchase (apart from the Be and Al lenses which are not nanofocusing devices).We aim at providing these on a daily basis to the 50% of UK users.