Linearly graded GeSi beam-expanding/compressing X-ray monochromator

Korytár, D.; Ferrari, C.; Mikulı́k, Petr; Vagovič, Patrik; Dobročka, Edmund; Áč, V.; Konopka, Piotr Jan; Erko, A.; Абросимов, Н. В.

doi:10.1107/s0021889809048109

Cited by 4 publications

(2 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Possible ways to compensate for the refractive angular shift of about 15 00 and thereby to increase the intensity throughput were summarized by Korytá r et al (2010); this paper also presented a preliminary study of a linearly graded GeSi V21 channel monochromator with both asymmetry angles of 15 . An intensity gain by a factor of more than six can be obtained compared with that of a reference pure Ge monochromator.…”

Section: Figurementioning

confidence: 99%

Potential use of V-channel Ge(220) monochromators in X-ray metrology and imaging

et al. 2013

Self Cite

View full text Add to dashboard Cite

While channel-cut crystals, in which the diffracting surfaces in an asymmetric cut are kept parallel, can provide beam collimation and spectral beam shaping, they can in addition provide beam compression or expansion if the cut is V-shaped. The compression/expansion ratio depends in this case on the total asymmetry factor. If the Ge(220) diffraction planes and a total asymmetry factor in excess of 10 are used, the rocking curves of two diffractors will have a sufficient overlap only if the second diffractor is tuned slightly with respect to the first one. This study compares and analyses several ways of overcoming this mismatch, which is due to refraction, when the Cu K 1 beam is compressed 21-fold in a V21 monochromator. A more than sixfold intensity increase was obtained if the matching was improved either by a compositional variation or by a thermal deformation. This provided an intensity gain compared with the use of a simple slit in a symmetrical channel-cut monochromator. The first attempt to overcome the mismatch by introducing different types of X-ray prisms for the required beam deflection is described as well. The performance of the V-shaped monochromators is demonstrated in two applications. A narrow collimated monochromatic beam obtained in the beam compressing mode was used for high-resolution grazing-incidence small-angle X-ray scattering measurements of a silicon sample with corrupted surface. In addition, a two-dimensional Bragg magnifier, based on two crossed V15 channel monochromators in beam expansion mode and tuned by means of unequal asymmetries, was successfully applied to high-resolution imaging of test structures in combination with a Medipix detector.

show abstract

Section: Figurementioning

confidence: 99%

Potential use of V-channel Ge(220) monochromators in X-ray metrology and imaging

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…The refraction effect reduces considerably the overlap of the rocking curves of the two diffractors (channel walls) and the output photon flux when the total compression (expansion) factor m = m 1 Â m 2 exceeds 10. Several solutions of this problem have been proposed (Servidori, 2002;Koryta ´r et al, 2010;A ´c ˇet al, 2010) and tested in the beam expansion mode for X-ray imaging (Koryta ´r et al, 2005;Ferrari et al, 2011;Vagovic ˇet al, 2013Vagovic ˇet al, , 2015. Here, the expansion of the beam after it has passed through an object reduces the apparent pixel size of a two-dimensional detector, enhancing the resolution of the object image.…”

Section: Introductionmentioning

confidence: 99%

Towards high-flux X-ray beam compressing channel-cut monochromators

et al. 2016

View full text Add to dashboard Cite

The issue of a high‐flux X‐ray beam compressing channel‐cut monochromator for applications in X‐ray metrology is addressed. A Ge(111) compressor with compression ratio 20.3 was designed on the principle of a combination of symmetric and highly asymmetric diffractions. A pilot application of the single‐point diamond technology (SPDT) to finish active surfaces of X‐ray optics was tested, providing 50% flux enhancement as compared to a Ge(220) counterpart prepared by traditional surface treatment. This is much more than the theoretical 22% forecast and shows the potential of SPDT for preparation of high‐flux X‐ray compressors with a high compression ratio, where highly asymmetric diffraction with a very low exit angle is inevitable. The implications for efficient collection of X‐rays from microfocus X‐ray sources are discussed. A comparison of Ge compressors with Ge parallel channel‐cut monochromators combined with a 50 µm slit shows the several times higher flux of the former, making them applicable in X‐ray diffraction experiments at medium resolution. Furthermore, the Ge(111) compressor was tested as a collimator in high‐resolution grazing‐incidence small‐angle X‐ray scattering (GISAXS) measurements of surface gratings, providing experimental resolution close to 400 nm. This is ∼100 nm smaller than that achieved with the Ge(220) compressor but still approximately twice that of commercial SAXS/GISAXS laboratory setups.

show abstract

Extreme X-ray beam compression for a high-resolution table-top grazing-incidence small-angle X-ray scattering setup

et al. 2013

View full text Add to dashboard Cite

The application of V-shaped channel-cut GeSi(220) and Ge(220) monochromators for one-dimensional extreme X-ray beam compression was tested on a table-top setup for grazing-incidence small-angle X-ray scattering (GISAXS) with a microfocus source. A lattice constant gradient and different asymmetry angles of the diffractors were employed to enhance the compression factor to 21 and 15, respectively. It was demonstrated that the output beam parameters in terms of the size, divergence, photon flux and spectral bandwidth surpass those of the slit collimators used traditionally in GISAXS. A beam size far below 100 mm allows a high-resolution spatial GISAXS mapping, while the reciprocal space resolution of $500 nm approaches the level of synchrotron measurements and allows a fast one-shot detection of high-resolution GISAXS patterns. An oversampling shifts the detection limit up to $1 mm. The very short design of the compact high-resolution table-top GISAXS setup is another advantage of the extreme beam compression. Benefits of V-shaped monochromators for mediumresolution X-ray diffraction experiments as a bonus application are demonstrated by a comparison with parallel channel-cut monochromators combined with a slit.

show abstract

Linearly graded GeSi beam-expanding/compressing X-ray monochromator

Cited by 4 publications

References 9 publications

Potential use of V-channel Ge(220) monochromators in X-ray metrology and imaging

Potential use of V-channel Ge(220) monochromators in X-ray metrology and imaging

Towards high-flux X-ray beam compressing channel-cut monochromators

Extreme X-ray beam compression for a high-resolution table-top grazing-incidence small-angle X-ray scattering setup

Contact Info

Product

Resources

About