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Abstract: The first operational prototype of a high-purity germanium (HPGe) detector developed within the European LEAPS-INNOV project is presented in this work. This prototype features a monolithic, multi-element sensor optimized for high-resolution X-ray spectroscopy in the hard X-ray regime, intended for handing high count rates of 30 Mcps, across a broad energy range (5–100 keV). The present prototype demonstrates a throughput of about 150–200 kcps/pixel, corresponding to a total count rate of about 1.5–2 Mcps for the full 10 element detector. We discuss here a complete laboratory-based characterization of the detector’s performance, as well as an on-beam evaluation at the BM05 beamline of the ESRF synchrotron facility, using monochromatic X-rays in the 20–50 keV energy range. We provide a detailed performance assessment that also includes a phenomenological defect-depth estimation model.

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Abstract: This study presents a comprehensive investigation of the dosimetric characteristics and sensitivity mapping of a CVD diamond radiation detector (VS-Pt) fabricated with platinum metal contacts. The detector’s performance was evaluated through a series of measurements, including I–V characteristics, signal-to-noise ratio, dose rate dependence, linearity, photoconductive gain, sensitivity, rise time, and reproducibility, using an X-ray tube source. The device underwent annealing, which led to improvements in sensitivity, with a linear response and increased photoconductive gain. The reproducibility of the device was found to be slightly higher than the IAEA’s recommended limit. Following this, a comparative sensitivity mapping study was performed using two synchrotron micro-beam facilities—NSLS and DLS—employing different micro-beam sizes. The investigation explored the effects of beam size, bias polarity, and step displacement on the spatial resolution and sensitivity of the device. Results showed that sensitivity was influenced by beam size, with smaller beam and step sizes yielding higher sensitivity, likely due to the priming effect. Bias polarity also played a significant role, with negative bias producing higher photocurrents, particularly near nitrogen lines in the diamond. Additionally, the annealed sample exhibited better homogeneity and faster rise times compared to the un-annealed version. The findings highlight the optimal conditions for synchrotron-based dosimetric measurements, providing valuable insights for improving detector performance in applications such as radiotherapy dosimetry, radiobiology, and beam monitoring at synchrotron facilities.

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Abstract: A Jungfrau-1M detector has undergone testing at Diamond Light Source. The Jungfrau series of detectors from PSI use integration and adaptive gain, to offer very high frame rate and dynamic range, suitable for high-flux and time-resolved measurements. They are becoming more widely used, to take advantage of increasing light source brightness. We report on our experiences in testing the performance of a Jungfrau-1M without illumination, with a laboratory X-ray tube and on a microfocus beamline. The Jungfrau-1M was found to be able to resolve single photons in the laboratory and on the beamline. It was confirmed that range switching from high to intermediate gain is associated with a discontinuity in the detector response. Two methods of dark frame subtraction were compared for their effect on minimizing this discontinuity. The Jungfrau-1M was found to be very effective for recording macromolecular crystallography diffraction patterns, with no apparent detriment from the discontinuity. The Diamond machine will be upgraded in 2028–9 and will operate at significantly higher flux than at present, necessitating increased use of integrating detectors, such as Jungfrau, in the future.

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Abstract: The JUNGFRAU detector is a charge integrating, high-frame-rate, imaging detector developed by the PSI detector group, originally to support the SwissFEL Aramis beamline. The detector includes adaptive gain switching to give single photon sensitivity whilst also allowing sufficient analogue dynamic range to record ∼10,000 12keV photons. The use of adaptive gains requires a multi-stage data correction procedure, factoring in the pedestal and gain value for each pixel for each gain mode: at 2kHz frame rate this makes for a non-trivial undertaking. At the SLS a data capture system for this has been developed, JUNGFRAUJOCH which uses a number of Xilinx FPGA boards to read the UDP data stream and perform the correction and the initial stage of data compression, before reading out to the CPU for compression. Whilst this is an effective solution, the technology choice of FPGA high level synthesis for programming has a very high barrier to entry. Some kind of hardware acceleration is however critical to ensure the correction and compression keep up with the data acquisition rate over the long term. At Diamond we are also acquiring a JUNGFRAU 9M detector, to use for rotation and serial crystallography on beamline I24. This brings us to the challenge: adopt JUNGFRAUJOCH or develop an alternative system, since the wider view of high throughput computing has changed over the last few years. Here we present an alternative system build around the NVIDIA Grace Hopper Superchip (GH200) which includes a 72 ARM NEOVERSE v2 CPU cores, an NVIDIA H100 GPU and high bandwidth memory (Figure 1). The capabilities of this system allow us to consider building a data capture, correction and initial analysis system to support the JUNGFRAU 9M detector at Diamond Light Source, using far more mainstream technologies (CUDA for the accelerator programming, SLS detector for the front-end data capture) and offering the opportunity to tailor the system to fit in with the use cases being developed at Diamond Light Source beamline I24. This development also takes the opportunity to explore alternative methods for representing the data, keeping the data from modules separated allowing parallelism in data capture and analysis.

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Abstract: In this project sensitivity mapping using a source of focused X-ray microbeam was performed on three fabricated samples (VS-Pt, HPS-Pt and HPS-Al/Pt). The VS-Pt sample was chosen due to its special features such as thin nitrogen lines and substrate area. The source of focused X-ray beam (from synchrotron micro-beam called Diamond Light Source, DLS) was investigated in order to choose the optimum conditions to obtain high resolution images of the nitrogen lines within the sample. Additionally the sensitivity mapping of HPS-Pt and HPS-Al/Pt was investigated to study the effect of beam size, step displacement, bias polarity, annealing, and electrical contact were studied on the homogeneity of current response in order to choose optimum conditions for synchrotron measurements. High spatial resolution maps obtained for VS-Pt sample with a micro step displacement of 10 μm or less. Photocurrent is affected by bias polarity; current at negative bias is higher than at positive bias. There are regions with high current thus taking more time to restore to baseline value. Time rises slowly near nitrogen line with stabilization time increasing with bias. For HPS-Al/Pt, as bias increases, homogeneity of current response does not improve. At different negative biases, HPS-Al/Pt exhibits high dark current, unstable signals, and very low photocurrent. For HPS-Pt, at a bias of +50 and –50 V, current response is uniform becoming more homogenous at 100 V, and improving further as the bias increases up to +200 V; making it the most suitable choice for synchrotron measurements.