| 1. |
- Pinaroli, G., et al.
(författare)
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PERCIVAL : Possible applications in X-ray micro-tomography
- 2020
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 15:2
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Tidskriftsartikel (refereegranskat)abstract
- X-ray computed micro-tomography (μCT) is one of the most advanced and common non-destructive techniques in the field of medical imaging and material science. It allows recreating virtual models (3D models), without destroying the original objects, by measuring three-dimensional X-ray attenuation coefficient maps of samples on the (sub) micrometer scale. The quality of the images obtained using μCT is strongly dependent on the performance of the associated X-ray detector i.e. to the acquisition of information of the X-ray beam traversing the patient/sample being precise and accurate. Detectors for μCT have to meet the requirements of the specific tomography procedure in which they are going to be used. In general, the key parameters are high spatial resolution, high dynamic range, uniformity of response, high contrast sensitivity, fast acquisition readout and support of high frame rates. At present the detection devices in commercial μCT scanners are dominated by charge-coupled devices (CCD), photodiode arrays, CMOS acquisition circuits and more recently by hybrid pixel detectors. Monolithic CMOS imaging sensors, which offer reduced pixel sizes and low electronic noise, are certainly excellent candidates for μCT and may be used for the development of novel high-resolution imaging applications. The uses of monolithic CMOS based detectors such as the PERCIVAL detector are being recently explored for synchrotron and FEL applications. PERCIVAL was developed to operate in synchrotron and FEL facilities in the soft X-ray regime from 250 eV to 1 keV and it could offer all the aforementioned technical requirements needed in μCT experiments. In order to adapt the system for a typical tomography application, a scintillator is required, to convert incoming X-ray radiation (∼ tens of KeV) into visible light which may be detected with high efficiency. Such a taper-based scintillator was developed and mounted in front of the sensitive area of the PERCIVAL imager. In this presentation we will report the setup of the detector system and preliminary results of first μCTs of reference objects, which were performed in the TomoLab at ELETTRA.
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| 2. |
- Wunderer, C. B., et al.
(författare)
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The Percival 2-Megapixel monolithic active pixel imager
- 2019
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- The peak brilliance reached by today's Free-Electron Laser and Synchrotron light sources requires photon detectors matching their output intensity and other characteristics in order to fully realize the sources' potential. The Pixellated Energy Resolving CMOS Imager, Versatile And Large (Percival) is a dedicated soft X-ray imager (0.25-1 keV) developed for this purpose by a collaboration of DESY, Rutherford Appleton Laboratory/STFC, Elettra Sincrotrone Trieste, Diamond Light Source, and Pohang Accelerator Laboratory. Following several generations of prototypes, the Percival "P2M" 2-Megapixel imager - a 4.5x5 cm monolithic, stitched sensor with an uninterrupted imaging area of 4x4 cm(2) (1408x1484 pixels of 27x27 mu m - was produced and has demonstrated basic functionality with a first-light image using visible light. It is currently being brought to full operation in a front-illuminated configuration. The readout system being commissioned in parallel has been developed specifically for this imager which will produce - at full 300 Hz frame rate - data at 20 Gbit/s. A first wafer with eight Percival P2M chips has undergone backthinning to enable soft X-ray detection. It has been diced and chips are currently being wirebonded. We summarize here the P2M system, the project status, and show the P2M sensor's first response to visible light.
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| 3. |
- Correa, J., et al.
(författare)
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On the Charge Collection Efficiency of the PERCIVAL Detector
- 2016
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Ingår i: Journal of Instrumentation. - : IOP. - 1748-0221. ; 11:12
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Tidskriftsartikel (refereegranskat)abstract
- The PERCIVAL soft X-ray imager is being developed by DESY, RAL, Elettra, DLS, and PAL to address the challenges at high brilliance Light Sources such as new-generation Synchrotrons and Free Electron Lasers. Typical requirements for detector systems at these sources are high frame rates, large dynamic range, single-photon counting capability with low probability of false positives, high quantum efficiency, and (multi)-mega-pixel arrangements. PERCIVAL is a monolithic active pixel sensor, based on CMOS technology. It is designed for the soft X-ray regime and, therefore, it is post-processed in order to achieve high quantum efficiency in its primary energy range (250 eV to 1 keV) . This work will report on the latest experimental results on charge collection efficiency obtained for multiple back-side-illuminated test sensors during two campaigns, at the P04 beam-line at PETRA III, and the CiPo beam-line at Elettra, spanning most of the primary energy range as well as testing the performance for photon-energies below 250 eV . In addition, XPS surface analysis was used to cross-check the obtained results.
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| 4. |
- Correa, J., et al.
(författare)
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The PERCIVAL detector : first user experiments
- 2023
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Ingår i: Journal of Synchrotron Radiation. - 0909-0495 .- 1600-5775. ; 30, s. 242-250
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Tidskriftsartikel (refereegranskat)abstract
- The PERCIVAL detector is a CMOS imager designed for the soft X-ray regime at photon sources. Although still in its final development phase, it has recently seen its first user experiments: ptychography at a free-electron laser, holographic imaging at a storage ring and preliminary tests on X-ray photon correlation spectroscopy. The detector performed remarkably well in terms of spatial resolution achievable in the sample plane, owing to its small pixel size, large active area and very large dynamic range; but also in terms of its frame rate, which is significantly faster than traditional CCDs. In particular, it is the combination of these features which makes PERCIVAL an attractive option for soft X-ray science.
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| 5. |
- Correa, J., et al.
(författare)
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The PERCIVAL soft X-ray Detector
- 2018
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Ingår i: 2018 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2018 - Proceedings. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538684948
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Konferensbidrag (refereegranskat)abstract
- The PERCIVAL collaboration to develop a soft X-ray imager able to address the challenges of high brilliance light sources, such as new-generation synchrotrons and Free Electron Lasers, has reached one of its major milestones: a full 2-MegaPixel (P2M) system (uninterrupted 4 × 4 cm2 active area) has already seen its first light.Smaller prototypes of the device, a monolithic active pixel sensor based on CMOS technology, have already been fully characterised, and have demonstrated high frame rate, large dynamic range, and relatively high quantum efficiency.The PERCIVAL modular layout allows for clover-leaf like arrangement of up to four P2M systems. Moreover, it will be post-processed in order to achieve a high quantum efficiency in its primary energy range (250 eV to 1 keV).We will present the P2M system, its status and newest results, bring these in context with achieved prototype performance, and outline future steps.
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| 6. |
- Graafsma, Heinz, et al.
(författare)
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PERCIVAL soft X-ray imager
- 2013
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Ingår i: IEEE Nuclear Science Symposium Conference Record. - : IEEE conference proceedings. - 9781479905348 ; , s. Art. no. 6829506-
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Konferensbidrag (refereegranskat)abstract
- Our goal is to provide the scientific community with a large (10cm × 10cm) pixellated detector featuring a large dynamic range (1-105 photons), good spatial resolution (27μm), good Quantum Efficiency (QE) in the low energy range (250eV-1keV), variable readout speed (up to 120 frames/s), i.e. with characteristics compatible with user needs at today's of low-energy Free Electron Lasers (FEL) and synchrotron sources. © 2013 IEEE.
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| 7. |
- Khromova, A., et al.
(författare)
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Report on recent results of the PERCIVAL soft X-ray imager
- 2016
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Ingår i: Journal of Instrumentation. - : IOP. - 1748-0221. ; 11:November
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Tidskriftsartikel (refereegranskat)abstract
- The PERCIVAL (Pixelated Energy Resolving CMOS Imager, Versatile And Large) soft X-ray 2D imaging detector is based on stitched, wafer-scale sensors possessing a thick epi-layer, which together with back-thinning and back-side illumination yields elevated quantum efficiency in the photon energy range of 125–1000 eV. Main application fields of PERCIVAL are foreseen in photon science with FELs and synchrotron radiation. This requires high dynamic range up to 105 ph @ 250 eV paired with single photon sensitivity with high confidence at moderate frame rates in the range of 10–120 Hz. These figures imply the availability of dynamic gain switching on a pixel-by-pixel basis and a highly parallel, low noise analog and digital readout, which has been realized in the PERCIVAL sensor layout. Different aspects of the detector performance have been assessed using prototype sensors with different pixel and ADC types. This work will report on the recent test results performed on the newest chip prototypes with the improved pixel and ADC architecture. For the target frame rates in the 10–120 Hz range an average noise floor of 14e− has been determined, indicating the ability of detecting single photons with energies above 250 eV. Owing to the successfully implemented adaptive 3-stage multiple-gain switching, the integrated charge level exceeds 4 centerdot 106 e− or 57000 X-ray photons at 250 eV per frame at 120 Hz. For all gains the noise level remains below the Poisson limit also in high-flux conditions. Additionally, a short overview over the updates on an oncoming 2 Mpixel (P2M) detector system (expected at the end of 2016) will be reported.
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| 8. |
- Marras, A., et al.
(författare)
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Experimental characterization of the PERCIVAL soft X-ray detector
- 2016
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Ingår i: 2015 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2015. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781467398626
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Considerable interest has been manifested for the use of high-brilliance X-ray synchrotron sources and X-ray Free-Electron Lasers for the investigation of samples.
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| 9. |
- Marras, A., et al.
(författare)
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Percival P2M-FSI detector : First test at a Synchrotron Ring beamline with tender x-ray photons
- 2019
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Ingår i: 2019 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2019. - : IEEE. - 9781728141640
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Konferensbidrag (refereegranskat)abstract
- In this paper, we are presenting the results of the first test of the Percival P2M-FSI detector with tender x-rays photons at a synchrotron beamline. Percival is a monolithic CMOS Imager for detection of x-rays in Synchrotron Rings and Free Electron Lasers: the Front-Side-Illuminated (FSI) version of the detector has been proven able to successfully distinguish tender (2keV) x-ray single photons.
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| 10. |
- Sedgwick, I., et al.
(författare)
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P2M : First Optical Characterisation Results of a 2MPixel CMOS Image Sensor for Soft X-Ray Detection
- 2019
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Ingår i: 2019 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE (NSS/MIC). - : IEEE. - 9781728141640
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Konferensbidrag (refereegranskat)abstract
- High brilliance synchrotrons and FELs require high performing detector systems to realise their full potential. High dynamic range, low noise and high frame rate are all of great importance. In this paper we present first optical characterization results of the P2M CMOS sensor, designed for soft X-ray detection at such facilities. Previous work is summarised and an overview of the sensor is presented. Test results for the sensor's column-parallel ADC and readout chain are presented, and first test results for the pixel acquired using the Photon Transfer Curve (PTC) method are shown. Finally, an outline of future work is provided.
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