P03, the microfocus and nanofocus X-ray scattering (MiNaXS) beamline of the PETRA III storage ring: the microfocus endstation

Abstract

The P03 beamline, also called the microfocus and nanofocus X-ray scattering (MiNaXS) beamline, exploits the excellent photon beam properties of the low-emittance source PETRA III to provide a microfocused/nanofocused beam with ultra-high intensity for time-resolved X-ray scattering experiments. The beamline has been designed to perform X-ray scattering in both transmission and reflection geometries. The microfocus endstation started user operation in May 2011. An overview of the beamline status and of some representative results highlighting the performance of the microfocus endstation at MiNaXS are given.

Figure 1

Sketch of the MiNaXS beamline optics. FS stands for fast shutter, Abs for Absorber, CRL for compound refractive lens, Q-bpm for quad beam position monitor and Exp for experiment. The distance from the undulator source is indicated in meters. Two lasers are available at the beamline. They are used for pre-alignment of the monochromator and the sample, respectively.

Figure 2

Calculated normalized intensity after the second mirror when using SiO₂ coating (red continuous line), Mo coating (green dashed line) or Pd coating (blue dotted line). The X-ray beam is reflected by the mirrors under a grazing incident angle of 2.27 mrad. The gray box indicates the X-ray energy range provided by the large offset monochromator at P03.

Figure 3

Drawing of a transfocator chamber and photograph of a transfocator at P03. The transfocator consists of eight blocks of Be lenses which can be moved either in or out of the monochromatic X-ray beam.

Figure 4

Beam size as a function of the lens-to-sample distance D _LS (N = 16 CRLs): horizontal FWHM (red squares), vertical FWHM (green circles). The error bars are shown below the symbol size. A parabolic approximation of the data is indicated by the lines. It can be used to determine the optimal focus position in the vertical (green dashed line) and horizontal (red solid line) directions.

Figure 5

Illustration of the microfocus endstation at MiNaXS: standard sample environment. The adaptive flight tube, detector device, optical microscope (a), and Pilatus 300k detector (b) are indicated.

Figure 6

Drawing of the in-vacuum beamstop device. Zoom-in: drawing of a 5 mm-diameter diode beamstop.

Figure 7

(a) Two-dimensional µSAXS data of a polyethylene (LUPOLEN) calibration sample. (b) Azimuthal integrated intensity. The vertical arrows highlight the positions of the first-order and second-order maxima of the LUPOLEN calibration sample. The SAXS resolution is imposed by the beamstop size as indicated by the star (*) at q = 0.05 ± 0.01  nm⁻¹.

Figure 8

(a) Photograph of the RF sputter deposition experiment set-up at MiNaXS. (b) Detector cut I[q _z(t)] at q _y = 0 nm⁻¹. The black areas correspond to the shadow of the specular beamstop and to the gaps in between modules of the Pilatus 300k detector. The curves are shifted for clarity. Resonant diffuse scattering stemming from the thin polymer film is indicated by the stars (***). (c) Out-of-plane cut I[q _y(t)] at α_f = α_c(Au). The curves are shifted for clarity. (d) µGISAXS data recorded at the MiNaXS beamline at an X-ray energy of 13.0 ± 0.1 keV, an incident angle of 0.435 ± 0.005°, a sample-to-detector distance of 4823 ± 2 mm and with an exposure time of 95 ms (exposure period 100 ms). The arrows indicate the positions of the detector (vertical arrow) and out-of-plane cuts (horizontal arrow) shown in (b) and (c), respectively. In this configuration the resolution limit is imposed by the beam divergence as indicated by the vertical dashed line at q _y = 0.005 ± 0.001 nm⁻¹ in (c).

Figure 9

Combined µGISAXS and imaging ellipsometry at MiNaXS. (a) Photograph of the experiment set-up (sample environment): (*) needle, highlighted by the red line; (1) ellipsometer laser arm; (2) ellipsometer detector arm; (3) optical microscope; (4) diode beamstop; (5) sample stage; (6) flight tube entrance window. (b) Ellipsometer data: delta (Δ) and psi (Ψ) as a function of time. (c) Out-of-plane cuts I[q _y(t)] at α_f = α_c(Si) as indicated by the arrows in the two-dimensional GISAXS data shown in (d): (A) t < 0 s, (B) t = 0 s, (C) t = 366 s, (D) t = 452 s and (E) t = 513 s. The time that a droplet of the gold nanoparticle solution was deposited onto the polymer template defines t = 0 s.