Kudo Togo, Suzuki Shinji, Sano Mutsumi, Itoga Toshiro, Masunaga Hiroyasu, Goto Shunji, Takahashi Sunao
Japan Synchrotron Radiation Research Institute, Sayo-cho 1-1-1, Sayo-gun, Hyogo 679-5198, Japan.
J Synchrotron Radiat. 2025 May 1;32(Pt 3):622-628. doi: 10.1107/S1600577525002838. Epub 2025 Apr 22.
Contamination from nearby bending magnet radiation hinders precise and accurate determination of the true beam center of undulator radiation. To solve this problem, a semi-nondestructive method was developed to visualize the detailed profile of a synchrotron radiation beam by using a thin diamond film as a scatterer. As the beam passed through the diamond film, scattered X-rays were imaged using a pinhole camera and measured with a two-dimensional silicon drift detector (SDD) scan. With this configuration, the beam center was accurately determined by visualizing the radiation pattern distribution for each energy level of a pink X-ray beam within an aperture size of 1.5 mm × 1.5 mm, shaped by a front-end slit (FES) positioned upstream of the monochromator. Additionally, by scanning the FES in two dimensions with a reduced aperture of 0.4 mm × 0.4 mm, energy-resolved images were successfully obtained using the SDD at a fixed position. These images revealed the profile of undulator radiation over a broad area (with an aperture extending up to 4 mm) in a pre-slit positioned upstream of the FES, demonstrating good alignment with SPECTRA calculations. This method effectively eliminates contamination from nearby bending magnet radiation, a significant issue in previous approaches, enabling a direct and highly accurate determination of the true beam center.
来自附近弯曲磁铁辐射的污染阻碍了对波荡器辐射真实束心的精确测定。为了解决这个问题,开发了一种半无损方法,通过使用薄金刚石膜作为散射体来可视化同步辐射束的详细轮廓。当光束穿过金刚石膜时,散射的X射线用针孔相机成像并用二维硅漂移探测器(SDD)扫描进行测量。采用这种配置,通过在由位于单色仪上游的前端狭缝(FES)形成的1.5 mm×1.5 mm孔径内可视化粉色X射线束每个能级的辐射图案分布,精确确定了束心。此外,通过用0.4 mm×0.4 mm的缩小孔径在二维方向上扫描FES,在固定位置使用SDD成功获得了能量分辨图像。这些图像揭示了在FES上游的预狭缝中大面积(孔径扩展到4 mm)上的波荡器辐射轮廓,与SPECTRA计算结果显示出良好的一致性。该方法有效消除了附近弯曲磁铁辐射的污染,这是先前方法中的一个重大问题,能够直接且高精度地确定真实束心。