Periodic Reporting for period 2 - FleX-RAY (Inherently Flexible X-Ray Imaging Detector using Single Photon Avalanche Photodiodes and Scintillating Fibres)
Reporting period: 2021-09-01 to 2024-01-31
Radiographic imaging is applied to various fields such as medicine, industrial non-destructive testing (NDT), experimental physics and nuclear monitoring so the need for continuous advancements and targeted research seems imperative. The H2020 FleX-RAY project has at its core the multifaceted science of radiographic imaging and aims at developing an inherently flexible radiographic imaging detector using Single Photon capable Avalanche Photodiodes and scintillating fibres.
In simple terms, Project FleX-RAY sought to rethink the existing detector architecture and evolve beyond its present-day rigidity. The current norm in radiography positions the readout electronics behind a scintillator in the beam path. However, FleX-RAY proposes to move the electronics and hardware to the side, outside the beam path resulting in reduced material and manufacturing costs while allowing for field maintenance.
As expected, the project’s concept required achieving several breakthroughs. Thus, the FleX-RAY consortium developed a repeatable method for manufacturing a new type of scintillating fibre that can allow the flexible detector to go beyond the state of the art in terms of resolution. A high-accuracy 3D shape sensor was also developed to accurately measure the shape of the flexible detector area to enable a spatial correction of the distorted x-ray image. In turn, this newly introduced fibre arrangement required new image reconstruction algorithms. A new custom fibre coupling system was also developed to enable high-density fibre readout. Scalable photodetector analogue front ends allowing for direct integration with FPGA electronics with high-speed event counting was implemented in an expandable IP core based architecture.
In simple terms, Project FleX-RAY sought to rethink the existing detector architecture and evolve beyond its present-day rigidity. The current norm in radiography positions the readout electronics behind a scintillator in the beam path. However, FleX-RAY proposes to move the electronics and hardware to the side, outside the beam path resulting in reduced material and manufacturing costs while allowing for field maintenance.
As expected, the project’s concept required achieving several breakthroughs. Thus, the FleX-RAY consortium developed a repeatable method for manufacturing a new type of scintillating fibre that can allow the flexible detector to go beyond the state of the art in terms of resolution. A high-accuracy 3D shape sensor was also developed to accurately measure the shape of the flexible detector area to enable a spatial correction of the distorted x-ray image. In turn, this newly introduced fibre arrangement required new image reconstruction algorithms. A new custom fibre coupling system was also developed to enable high-density fibre readout. Scalable photodetector analogue front ends allowing for direct integration with FPGA electronics with high-speed event counting was implemented in an expandable IP core based architecture.
During theFleX-RAY project, the consortium focused on a variety of concrete objectives and goals that led to achieving specific innovations necessary for the fulfillment of the project. The partners, having well-delineated responsibilities, engaged in extensive technical and scientific research, dove into simulations while tackling risks and challenges that could impact the project’s future. More specifically, initial focus was put on building a simulation framework for all involved parties to collect valuable information that could prove useful for subsequent tasks. By project end, several prototypes of several geometries for the scintillating fibres were developed and were experimentally tested using a variety of sources such as X-rays, beta-particles and gamma rays. The results gathered exhibit great potential for the FleX-RAY solution in a variety of applications ranging from X-Ray non-destructive testing to gamma radiography and muography.
On the coupling methodology front, a coupling system that could achieve minimal optical power loss was developed and used in multiple experiments. Concerning the FleX-RAY algorithms, image reconstruction saw substantial progress through the development of two different methods that can simultaneously achieve noise rejection as well as image enhancement through sensor gain equalization.
Regarding the 3D shape sensing development, a high accuracy sensor was developed and tested within a radiation environment for stability. Multiple small-scale prototypes were developed to showcase the capabilities of the overall concept.
Last but not least, on the hardware side, photon-counting sensor electronics were developed and readout ASICs were evaluated, whilst a TDC architecture capable of <5ps resolution was implemented and tested in FPGA hardware.
On the coupling methodology front, a coupling system that could achieve minimal optical power loss was developed and used in multiple experiments. Concerning the FleX-RAY algorithms, image reconstruction saw substantial progress through the development of two different methods that can simultaneously achieve noise rejection as well as image enhancement through sensor gain equalization.
Regarding the 3D shape sensing development, a high accuracy sensor was developed and tested within a radiation environment for stability. Multiple small-scale prototypes were developed to showcase the capabilities of the overall concept.
Last but not least, on the hardware side, photon-counting sensor electronics were developed and readout ASICs were evaluated, whilst a TDC architecture capable of <5ps resolution was implemented and tested in FPGA hardware.
After having concluded its course, the FleX-RAY project offered valuable scientific and technological progress to accommodate the implementation of flexible digital radiography in various industries. The principal targeted innovations of the project and their future applications are:
- The construction of a scintillating fibre-based radiography detector capable of being utilized in X-Ray, Gamma-Ray and cosmic particle based imaging.
- The development of flexible glass foils with optically integrated sensors fit for 3D shape sensing.
- The production of scalable, configurable & parallel Time to Digital Converters for multi-channel timing applications that can be implemented in scalable single-photon experiments and quantum applications.
- The concretisation of a repeatable and leak free hollow optical fibre infiltration process with potential applications in optics, radiation detection and sensing.
- The formulation of low-temperature capable optical fiber-photodetector quick coupling design and process that can be applied in waveguide optical solutions.
- The development of real-time calculation of the point spread function of scintillating fibre-based imaging detectors and fast image deconvolution algorithms suitable for ionising radiation or particle detectors.
- The construction of a scintillating fibre-based radiography detector capable of being utilized in X-Ray, Gamma-Ray and cosmic particle based imaging.
- The development of flexible glass foils with optically integrated sensors fit for 3D shape sensing.
- The production of scalable, configurable & parallel Time to Digital Converters for multi-channel timing applications that can be implemented in scalable single-photon experiments and quantum applications.
- The concretisation of a repeatable and leak free hollow optical fibre infiltration process with potential applications in optics, radiation detection and sensing.
- The formulation of low-temperature capable optical fiber-photodetector quick coupling design and process that can be applied in waveguide optical solutions.
- The development of real-time calculation of the point spread function of scintillating fibre-based imaging detectors and fast image deconvolution algorithms suitable for ionising radiation or particle detectors.