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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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
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
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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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M. C.
Veale
,
S.
Bell
,
B. D.
Cline
,
I.
Church
,
S.
Cross
,
C.
Day
,
M.
French
,
T.
Gardiner
,
N.
Ghorbanian
,
M. D.
Hart
,
L. L.
Jones
,
J.
Lipp
,
T.
Nicholls
,
J.
Nobes
,
M.
Prydderch
,
A.
Schneider
,
P.
Seller
,
D.
Sole
,
M. D.
Wilson
,
V.
Dhamgaye
,
O.
Fox
,
K.
Sawhney
Diamond Proposal Number(s):
[32491]
Open Access
Abstract: The HEXITECMHz ASIC is the next generation of the STFC's High Energy X-ray Imaging Technology (HEXITEC). With a ×100 increase in the camera frame rate to 1 MHz, the new ASIC is capable of delivering fully spectroscopic X-ray imaging at photon fluxes of 2×106 photons s-1 mm-2. The improved flux capability ensures the relevance of the technology at a new generation of difraction-limited storage ring (DLSR) synchrotrons as well as enabeling dynamic spectroscopic imaging with sub-keV energy resolution to be carried out on millisecond timescales. In this paper preliminary results from X-ray testing of a 0.3 mm thick p-type Si sensor and 2.0 mm thick HF-CdZnTe sensor at the Diamond Light Source Synchrotron are presented for the first time. Each module consists of 80 × 80 pixels on a 250 μm pixel pitch operated at a temperature of 20°C and a frame rate of 1 MHz. For these preliminary measurements, testing was completed using a prototype test system which limited readout to a portion of the 1 MHz output sampled over an SPI test interface at ∼50 Hz. Despite this limitation these measurements allow the spectroscopic performance of the ASIC to be characterised ahead of the full DAQ system. The prototype detectors were characterised using monochromatic X-rays with energies 12–35 keV at fluxes of (0.6 – 2.5) × 106 photons s-1 mm-2. At an X-ray energy of 12 keV, the energy resolution of the p-type Si and HF-CdZnTe detectors were measured to be 1.0 keV and 1.1 keV respectively. At the higher energies of 20 keV and 35 keV the energy resolution in the HF-CdZnTe was measured to be 1.2 keV and 1.4 keV respectively.
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Jul 2023
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B16-Test Beamline
Optics
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Diamond Proposal Number(s):
[28044, 33737]
Open Access
Abstract: Visible light optical elements such as lenses and mirrors have counterparts for X-rays. In the visible regime, a variable focusing power can be achieved by an Alvarez lens which consists of a pair of inline planar refractors with a cubic thickness profile. When the two refractors are laterally displaced in opposite directions, the parabolic component of the wavefront is changed resulting in a longitudinal displacement of the focus. This paper reports an implementation of this concept for X-rays using two planar microfabricated refractive elements. The Alvarez X-ray lens can vary the focal distance of an elliptical X-ray mirror or a planar compound X-ray lens over several millimetres. The study presents the first demonstration of an Alvarez X-ray lens which adaptively corrects defocus and astigmatism aberrations of X-ray optics. In addition, the Alvarez X-ray lens eliminates coma aberration in an elliptical mirror, to the lowest order, when combining the lens with an adjustment of the pitch angle of the mirror.
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Jul 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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B16-Test Beamline
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Open Access
Abstract: Alanine pellets with a nominal thickness of 0.5 mm and diameter of 5 mm were irradiated with monoenergetic x-rays at the Diamond Light Source synchrotron, to quantify their response in the 8 to 20 keV range relative to 60Co radiation. The absorbed dose to graphite was measured with a small portable graphite calorimeter, and the DOSRZnrc code in the EGSnrc Monte Carlo package was used to calculate conversion factors between the measured dose to graphite and the absorbed dose to water delivered to the alanine pellets. GafChromic EBT3 films were used to measure the beam profile for modelling in the MC simulations. The relative responses measured in this energy range were found to range from 0.616 to 0.643, with a combined relative expanded uncertainty of 3.4% to 3.5% (k = 2), where the majority of the uncertainty originated from the uncertainty in the alanine readout, due to the small size of the pellets used. The measured values were in good agreement with previously published data in the overlapping region of x-ray energies, while this work extended the dataset to lower energies. By measuring the response to monoenergetic x-rays, the response to a more complex broad-spectrum x-ray source can be inferred if the spectrum is known, meaning that this work supports the establishment of alanine as a secondary standard dosimeter for low-energy x-ray sources.
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Feb 2023
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