B16-Test Beamline
Optics
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Yuanze
Xu
,
Vishal
Dhamgaye
,
Hongchang
Wang
,
Oliver
Fox
,
Futing
Yi
,
Ming
Li
,
Weiwei
Zhang
,
Junliang
Yang
,
David
Laundy
,
Dongni
Zhang
,
Kawal
Sawhney
,
Jing
Liu
,
He
Lin
Diamond Proposal Number(s):
[34816]
Open Access
Abstract: A novel aberration-free X-ray compound refractive kinoform lens design based on the Cartesian oval curve is presented, designated as the OVAL-OK (OVAL Overlap Kinoform) lens. Material infilling of the kinoform step structure maintains focal spot dimensions while reducing focal intensity and reproducibility of structures. A SU-8 OVAL-OK lens fabricated through X-ray lithography achieved vertical focal sizes of 70.8 nm (knife-edge scanning) and 56 nm (wavefront propagation analysis) under 15 keV X-ray illumination, using a 120 μm × 200 μm (horizontal × vertical) aperture and 40.8 mm working distance. The lens exhibits a horizontal structural depth of 170 μm and a minimum feature size of 5 μm. The observed discrepancy between direct knife-edge measurements and wavefront-derived values is attributable to the combined effects of geometric, diffraction, coherence, instrumental instability, etc. These results demonstrate the potential for achieving sub-50 nm 2D focusing in future iterations through enhanced structural depth and expanded aperture dimensions.
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Apr 2026
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B16-Test Beamline
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S.-X.
Wang
,
Z.-Q.
Zhao
,
X.-Y.
Wang
,
T.-J.
Li
,
Y.
Su
,
Y.
Uemura
,
F.
Alves Lima
,
A.
Khadiev
,
B.-H.
Wang
,
J. M.
Ablett
,
J.-P.
Rueff
,
H.-C.
Wang
,
O. J. L.
Fox
,
Wenbin
Li
,
L.-F.
Zhu
,
X.-C.
Huang
Diamond Proposal Number(s):
[31397]
Open Access
Abstract: X-ray cavity quantum optics with inner-shell transitions has been limited by the spectral overlap between resonant and continuum states. Here, we report the first experimental demonstration of cavity-controlled core-to-core resonant inelastic x-ray scattering (RIXS). We suppress the absorption-edge effects by monitoring the RIXS profile, thereby resolving the resonant state from the overlapping continuum. We observe distinct cavity-induced energy shifts and cavity-enhanced decay rates in the 2𝑝3𝑑 RIXS spectra of WSi2. These effects, manifesting as stretched or shifted profiles in the RIXS planes, enable novel spectroscopic applications via cavity-controlled core-hole states. Our results establish core-to-core RIXS as a powerful tool to manipulate inner-shell dynamics in x-ray cavities, offering new avenues for integrating quantum optical effects with x-ray spectroscopy.
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Feb 2026
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B16-Test Beamline
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B.
Cline
,
D.
Banks
,
M.
Bishop
,
A.
Davis
,
J.
Harris
,
M.
Hart
,
S.
Knowles
,
T.
Nicholls
,
J.
Nobes
,
S.
Pradeep
,
M.
Roberts
,
M. C.
Veale
,
M. D.
Wilson
,
V. P.
Dhamgaye
,
O. J. L.
Fox
,
K. J. S.
Sawhney
,
S.
Scully
Diamond Proposal Number(s):
[36472]
Open Access
Abstract: In this paper, results are presented from the characterisation of a 2 mm thick Redlen Technologies high-flux-capable Cadmium Zinc Telluride (HF-CZT) sensor hybridised to the small-pixel, spectroscopic-imaging HEXITEC_MHz ASIC. Dynamic datasets were taken on the B16 Test Beamline at the Diamond Light Source to study a previously-identified 'excess-leakage-current' phenomenon in HF-CZT, where additional leakage current was temporarily generated upon the application of an X-ray flux. A study of the response of the detector as a function of X-ray intensity demonstrated a measurable excess leakage current signal above 105 ph s-1 mm-2. At a 20 keV flux of 7.81 × 106 ph s-1 mm-2, this effect contributed a signal equivalent to 3.79 ± 1.59 nA mm-2in addition to the expected photocurrent. On removal of X-rays at this flux, this excess leakage current took ∼ 10 s to decay below the noise floor of the detector. This long lifetime has implications for detectors required to operate at high frame rates and fluxes. The use of a small-pixel detector also allowed the spatial variation of this effect to be studied. A per-pixel comparison between the magnitude of the excess leakage current and the spectroscopic performance of the pixel showed no correlation. This suggests that the phenomenon is less likely to be a bulk-crystal effect and more likely the result of the properties of the CZT surface or metal/semiconductor interface. An Arrhenius analysis of the temperature-dependence of the dark and excess leakage currents in the detector yielded values of 0.69 ± 0.04 eV and 0.13 ± 0.01 eV respectively. The change in dark current with temperature is consistent with deep levels pinning the Fermi level close to the mid band gap, whilst the activation energy of the excess leakage current suggests shallower defects at the metal-semiconductor interface are responsible.
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Oct 2025
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B16-Test Beamline
Optics
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Open Access
Abstract: For monochromators and phase retarders designed for X-rays of energy over 4 keV, diffracting crystals are the material of choice. However, the cleanliness of the diffracted beam and the achievable energy resolution can be degraded by defects introduced into the bulk during growth, by scratches and pits left on the surface by polishing, and by poor clamping that deforms the crystal lattice. Diamond Light Source now has a procedure for inspecting such crystals before beamline installation, and within this, X-ray topography is a critical tool. New crystal optics are examined at the versatile bending-magnet test beamline B16, which is designed to apply topographic techniques using both white and monochromatic X-ray beams to crystals mounted in any orientation. Rocking curve imaging has been performed with a range of fields of view and spatial resolutions down to 2 µm using a set of digital detectors. Maps of defects over large surfaces have been collected using both on-the-fly scans and stitching techniques, and methods to automate stitching are being developed. Monochromator crystals, including some that were fabricated using new methods or mounted in innovative ways, have been successfully tested for strain under realistic cryocooling, and the results are helping to further improve the crystal mount and cooling. Results provided by X-ray topography are being combined with visible-light measurements made at Diamond's Optical Metrology Laboratory into a full package of techniques for determining whether a new crystal optic should be accepted. Not only Diamond's own beamlines, but also industrial users and other X-ray synchrotron facilities, have profited from this combination of capabilities.
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May 2025
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B16-Test Beamline
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Diamond Proposal Number(s):
[28722]
Open Access
Abstract: This paper presents a novel method of using cumulative integrated intensity (CII) to analyse rocking curve x-ray diffraction imaging (RC-XRDI) data. This method overcomes several limitations of traditional complex non-ideal curve fitting, which often results in inaccurate peak detection and full width at half maximum (FWHM) extraction. These complex non-ideal rocking curves arise in cases where additional features are present, such as peak splitting and multiple peaks. The application of the method also avoids the need for curve fitting and time-consuming calculations, allowing the extraction of peak widths at various normalized height-intensities (FWxM) and revealing extra information about defects. By analysing the broadening and peak position of the rocking curves for different defects, RC-XRDI provides insights into the nature and distribution of these defects within the material. Applied to RC-XRDI of a 4H-SiC 10 μm-thick homo-epitaxial layer on a substrate, the CII method was used to detect shifts in peak position and generate maps of full width at 1%, 10%, and 50% of maximum intensity, offering a detailed view of defect-induced broadening. Our results demonstrate that the CII method provides improved accuracy and requires fewer computations compared to curve-fitting techniques, making it particularly useful where precise defect characterization is critical. Moreover, background intensity was detected pixel-by-pixel using cubic smoothing splines, and the CII method provided robust validation for the precision of this background detection.
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May 2025
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B16-Test Beamline
Optics
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Xujie
Tong
,
Vishal
Dhamgaye
,
Qiucheng
Chen
,
Qingxin
Wu
,
Biao
Deng
,
Ling
Zhang
,
Oliver
Fox
,
Hongchang
Wang
,
Jun
Zhao
,
Yifang
Chen
,
Zijian
Xu
,
Peng
Li
,
Kawal
Sawhney
Diamond Proposal Number(s):
[32834]
Open Access
Abstract: Hard X-ray microscopes with 20–30 nm spatial resolution ranges are an advanced tool for the inspection of materials at the nanoscale. However, the limited efficiency of the focusing optics, for example, a Fresnel zone plate (ZP) lens, can significantly reduce the power of a nanoprobe. Despite several reports on ZP lenses that focus hard X-rays with 20 nm resolution – mainly constructed by zone-doubling techniques – a systematic investigation into the limiting factors has not been reported. We report the structural effects on the focusing and imaging efficiency of 20–30 nm-resolution ZPs, employing a modified beam-propagation method. The zone width and the duty cycle (zone width/ring pitch) were optimized to achieve maximum efficiency, and a comparative analysis of the zone materials was conducted. The optimized zone structures were used in the fabrication of Pt-hydrogen silsesquioxane (HSQ) ZPs. The highest focusing efficiency of the Pt-HSQ-ZP with a resolution of 30 nm was 10% at 7 keV and >5% in the range 6–10 keV, whereas the highest efficiency of the Pt-HSQ-ZP with a resolution of 20 nm was realized at 7 keV with an efficiency of 7.6%. Optical characterization conducted at X-ray beamlines demonstrated significant enhancement of the focusing and imaging efficiency in a broader range of hard X-rays from 5 keV to 10 keV, demonstrating the potential application in hard X-ray focusing and imaging.
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Nov 2024
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B16-Test Beamline
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B. D.
Cline
,
D.
Banks
,
S.
Bell
,
I.
Church
,
A.
Davis
,
T.
Gardiner
,
J.
Harris
,
M.
Hart
,
L.
Jones
,
T.
Nicholls
,
J.
Nobes
,
S.
Pradeep
,
M.
Roberts
,
D.
Sole
,
M. C.
Veale
,
M. D.
Wilson
,
V.
Dhamgaye
,
O.
Fox
,
K.
Sawhney
Diamond Proposal Number(s):
[32772]
Open Access
Abstract: In this paper, results are presented from the characterisation of Redlen Technologies high-flux-capable Cadmium Zinc Telluride (HF-CZT) hybridised to the HEXITECMHz ASIC, a novel 1 MHz continuous X-ray imaging system. A 2 mm thick HF-CZT HEXITECMHz detector was characterised on the B16 Test Beamline at the Diamond Light Source and displayed an average FWHM of 850 eV for monochromatic X-rays of energy 20 keV. Measurements revealed a shift in the baseline of irradiated pixels that results in a movement of the entire spectrum to higher ADU values. Datasets taken to analyse the effect's dynamics showed it to be highly localised and flux-dependent, with the excess leakage current generated equivalent to per-pixel shifts of ∼ 543 pA (8.68 nA mm-2) at a flux of 1.26×107 ph s-1 mm-2. Comparison to results from a p-type Si HEXITECMHz device indicate this `excess leakage-current' effect is unique to HF-CZT and it is hypothesised that it originates from trapping at the electrode-CZT interface and a temporary modification of the potential barrier between the CZT and metal electrode.
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Apr 2024
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B16-Test Beamline
Optics
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Diamond Proposal Number(s):
[32391, 30943, 20983, 19945]
Open Access
Abstract: Diffracting crystals are extensively used at synchrotron beamlines as x-ray monochromators and phase retarders. Imperfect growth processes, surface damage occurring during fabrication, and strain caused by poor clamping methods can all degrade the quality of these crystals and the x-ray beams diffracted by them. Because x-ray topography of these crystals can reveal both the location and the magnitude of these defects, it is now regularly used as an acceptance test for diffracting crystal optics at the Diamond Light Source synchrotron. Before installation on beamlines, crystal optics are inspected at the versatile bending-magnet B16 Test Beamline, where a variety of topographic techniques have been implemented with both white and monochromatic x-ray beams. A set of digital detectors permits rocking curve imaging with a choice of fields of view and spatial resolution down to 2 μm. Test crystals may be mounted in a variety of geometries according to need. For inspecting monochromator crystals fabricated for imaging applications, both on-the-fly scans and stitching techniques have been used to compose maps of surface defects. First crystals of multi-crystal monochromators have been tested under realistic cryocooled conditions, and their design has been improved to minimize strain. The Diamond Light Source’s x-ray topography program serves not only its own beamlines, but also industrial users and other x-ray synchrotron facilities.
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Oct 2023
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B16-Test Beamline
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B. D.
Cline
,
D.
Banks
,
S.
Bell
,
I.
Church
,
S.
Cross
,
A.
Davis
,
C.
Day
,
M.
French
,
T.
Gardiner
,
N.
Ghorbanian
,
J.
Harris
,
M.
Hart
,
J.
Holden
,
J.
Lipp
,
T.
Nicholls
,
J.
Nobes
,
S.
Pradeep
,
M.
Prydderch
,
M.
Roberts
,
A.
Schneider
,
P.
Seller
,
D.
Sole
,
M. C.
Veale
,
M. D.
Wilson
,
W.
Helsby
,
V.
Dhamgaye
,
O.
Fox
,
K.
Sawhney
Diamond Proposal Number(s):
[32772]
Abstract: Spectroscopic X-ray imaging techniques including Compton X-ray Imaging, X-ray Fluorescence Imaging and Hyperspectral X-ray Tomography require energy-resolving detectors capable of operating at high incident X-ray fluxes to make time resolved measurements. HEXITECMHz, operates at a continuous 1 MHz frame rate and can make fully spectroscopic measurements at >106 ph s−1 mm−2. This is enabled by an integrating Front End, in-pixel digitisation and high-speed serialisers. A 300 μm thick p-type Si HEXITECMHz detector was characterised on the B16 Test Beamline at the Diamond Light Source and are the first measurements taken at a 1 MHz frame rate. At 10 keV and 15 keV) the device displayed average FWHM of 656 eV and 682 eV respectively, with minimal changes in spectroscopic performance over ∼8 h. Analysis of charge-sharing events show low charge loss and a linear energy-signal response. Higher-flux measurements illustrated the capability of the ASIC to operate as a photon-counting device.
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Sep 2023
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B16-Test Beamline
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Diamond Proposal Number(s):
[29861]
Open Access
Abstract: Confocal micro-X-ray fluorescence analysis (CMXRF), using polycapillary optics, is a powerful technique for the non-destructive investigation of the three-dimensional elemental distribution of samples from many different research areas, including biology, cultural heritage and material science. To solve the problem of the quantitative interpretation of CMXRF measurements, voxTrace introduces a new fundamental Monte-Carlo ray-tracing approach, to simulate the measured spectra. This enables the consideration of effects such as secondary excitation, elastic and inelastic scattering. Furthermore, measurements with step sizes between measurement points smaller than the average confocal volume can be interpreted without complicated sample reconstruction algorithms. Solving this problem of high computational effort, in reasonable timescales, is made feasible by the effective use of graphics processing units (GPU) with CUDA.
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Jul 2023
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