Browsing by Author "Bizarri, Gregory"

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    Advances in design of high-performance heterostructured scintillators for time-of-flight positron emission tomography
    (Wiley, 2023-10-10) Krause, Philip George; Rogers, Edith; Bizarri, Gregory
    Core to advancing time-of-flight positron emission tomography (ToF-PET) toward a less invasive, more flexible procedure with a higher diagnostic power is the development of enhanced radiation detector materials. One promising avenue is the development of heterostructured scintillators where multiple materials work in synergy to exceed the performance of each individual component. Applied to ToF-PET detectors, one component contributes predominantly to the absorption of gamma rays and the other to the creation of ultra-fast photons. Whilst other authors have proposed various concepts, heterostructured scintillators are still in their infancy and scientifically guiding their development remains a challenge. Toward this aim and based on simulation and modeling developments, heterostructure properties are directly linked to ToF-PET performance. This is made possible by redefining the notions of detector photo-peak efficiency and timing response, as defined for monolithic detectors, in the context of heterostructured scintillators. Their overall potential is then discussed as a function of the materials and design used. This provides a quantitative framework to rapidly and efficiently support the advancement of heterostructured detectors for ToF-PET technology.
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    Cryogenic scintillation properties of n-type GaAs for the direct detection of MeV/c2 dark matter
    (AIP Publishing, 2018-03-20) Derenzo, S.; Bourret, Edith D.; Hanrahan, S.; Bizarri, Gregory
    This paper is the first report of n-type GaAs as a cryogenic scintillation radiation detector for the detection of electron recoils from interacting dark matter (DM) particles in the poorly explored MeV/c2 mass range. Seven GaAs samples from two commercial suppliers and with different silicon and boron concentrations were studied for their low temperature optical and scintillation properties. All samples are n-type even at low temperatures and exhibit emission between silicon donors and boron acceptors that peaks at 1.33 eV (930 nm). The lowest excitation band peaks at 1.44 eV (860 nm), and the overlap between the emission and excitation bands is small. The X-ray excited luminosities range from 7 to 43 photons/keV. Thermally stimulated luminescence measurements show that n-type GaAs does not accumulate metastable radiative states that could cause afterglow. Further development and use with cryogenic photodetectors promises a remarkable combination of large target size, ultra-low backgrounds, and a sensitivity to electron recoils of a few eV that would be produced by DM particles as light as a few MeV/c2.
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    Data supporting 'Two-dimensional perovskite functionalized fiber-type heterostructured scintillators'
    (Cranfield University, 2023-02-22 12:04) Rogers, Edith; Danang Birowosuto, Muhammad; Maddalena, Francesco; Dujardin, Christophe; Pagano, Fiammetta; Kratochwil, Nicolaus; Auffray, Etiennette; george Krause, Philip; Bizarri, Gregory
    Data used to produce the article "Two-dimensional perovskite functionalized fibre-type heterostructured scintillators" Data used to create the 2D histograms of charge (fig 2) and the CTR plots (fig 3)
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    Design rules for time of flight Positron Emission Tomography (ToF-PET) heterostructure radiation detectors
    (Elsevier, 2022-06-27) Krause, Philip George; Rogers, Edith; Birowosuto, Muhammad Danang; Pei, Qibing; Auffray, Etiennette; Vasil'ev, Andrey N.; Bizarri, Gregory
    Despite the clinical acceptance of ToF-PET, there is still a gap between the technology's performance and the end-user's needs. Core to bridging this gap is the ability to develop radiation detectors combining a short attenuation length and a sub-nanosecond time response. Currently, the detector of choice, Lu2SiO5:Ce3+ single crystal, is not selected for its ability to answer the performance needs, but as a trade-off between requirements and availability. To bypass the current performance limitations, in particular restricted time response, the concept of the heterostructured detector has been proposed. The concept aims at splitting the scintillation mechanisms across two materials, one acting primarily as an absorber and one as an ultra-fast emitter. If the concept has attracted the interest of the medical and material communities, little has been shown in terms of the benefits/limitations of the approach. Based on Monte Carlo simulations, we present a survey of heterostructure performance versus detector design. The data allow for a clear understanding of the design/performance relationship. This, in turn, enables the establishment of design rules toward the development and optimization of heterostructured detectors that could supersede the current detector technology in the medical imaging field but also across multiple sectors (e.g. high-energy physics, security).
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    Enhancing large-area scintillator detection with photonic crystal cavities
    (American Chemical Society, 2022-12-02) Ye, Wenzheng; Bizarri, Gregory; Birowosuto, Muhammad Danang; Wong, Liang Jie
    Scintillators are materials that emit visible photons when bombarded by high-energy particles (X-ray, γ-ray, electrons, neutrinos, etc.) and are crucial for applications, including X-ray imaging and high-energy particle detection. Here, we show that one-dimensional (1D) photonic crystal (PhC) cavities, added externally to scintillator materials, can be used to tailor the intrinsic emission spectrum of scintillators via the Purcell effect. The emission spectral peaks can be shifted, narrowed, or split, improving the overlap between the scintillator emission spectrum and the quantum efficiency (QE) spectrum of the photodetector. As a result, the overall photodetector signal can be enhanced by over 200%. The use of external PhC cavities especially benefits thick and large-area scintillators, which are needed to stop particles with ultrahigh energy, as in large-area neutrino detectors. Our findings should pave the way to greater versatility and efficiency in the design of scintillators for applications, including X-ray imaging and positron emission tomography.
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    Fast emitting nanocomposites for high-resolution ToF-PET imaging based on multicomponent scintillators
    (Wiley, 2024-02-28) Orfano, Matteo; Pagano, Fiammetta; Mattei, Ilaria; Cova, Francesca; Secchi, Valeria; Bracco, Silvia; Rogers, Edith; Barbieri, Luca; Lorenzi, Roberto; Bizarri, Gregory; Auffray, Etiennette; Monguzzi, Angelo
    Time-of-Flight Positron Emission Tomography (ToF-PET) is a medical imaging technique, based on the detection of two back-to-back γ-photons generated from radiotracers injected into the body. Its limit is the ability of employed scintillation detectors to discriminate in time the arrival of γ-pairs, that is, the coincidence time resolution (CTR). A CTR < 50 ps will enable fast imaging with ultralow radiotracer dose. Monolithic materials do not have simultaneously the required high light output and fast emission characteristics, thus the concept of scintillating heterostructure is proposed, where the device is made of a dense scintillator coupled to a fast-emitting light material. Here a composite polymeric scintillator loaded with hafnium oxide nanoparticles is presented. This enhanced by +300% its scintillation yield, by surpassing commercial plastic scintillators. The nanocomposite is coupled to bismuth germanate oxide (BGO) realizing a multilayer metascintillator. The energy sharing between its components is observed, which activates the nanocomposite's fast emission enabling a net CTR improvement of 25% with respect to monolithic BGO. These results demonstrate that a controlled loading with dense nanomaterials is an excellent strategy to enhance the performance of polymeric scintillators for their use in advanced radiation detection and imaging technologies.
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    Feasibility study of composite and multi-modality detector materials surface functionalisation requirements.
    (2018-09) Mazidi, Aimal; Bizarri, Gregory
    Reaching social limits within health care, security and energy physics, a demand for development of current technologies in radiation detection is becoming more urgent. A proposition is to develop a multi-modality heterostructure radiation detectors with ability to bypass performance of the current technological limitations. With successful results in this multi-disciplinary research project involving, material processing, computer simulation and manufacturing we impact greatly the social challenges we are facing today such as need for better health care system, safer social security, cleaner and more efficient energy as well as enhancing modern physics. Global aim of the project is to demonstrate heterostructure radiation detector to have high performance, being ultra-fast, with high stopping power with comparison to the current time of flight positron emission tomography detectors. My part within the project is to improve light transport within the heterostructure by functionalisation all the heterostructure surfaces (Lu2SiO5/ZnO interfaces and outer surfaces).
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    Horizons of modern molecular dynamics simulation in digitalized solid freeform fabrication with advanced materials
    (Elsevier, 2020-09-22) Goel, Saurav; Knaggs, Michael; Goel, Gaurav; Zhou, Xiaowang W.; Upadhyaya, Hari M.; Thakur, Vijay Kumar; Kumar, Vinod; Bizarri, Gregory; Tiwari, Ashutosh; Murphy, Adrian; Stukowski, Alexander; Matthews, Allan
    Our ability to shape and finish a component by combined methods of fabrication including (but not limited to) subtractive, additive, and/or no theoretical mass-loss/addition during the fabrication is now popularly known as solid freeform fabrication (SFF). Fabrication of a telescope mirror is a typical example where grinding and polishing processes are first applied to shape the mirror, and thereafter, an optical coating is usually applied to enhance its optical performance. The area of nanomanufacturing cannot grow without a deep knowledge of the fundamentals of materials and consequently, the use of computer simulations is now becoming ubiquitous. This article is intended to highlight the most recent advances in the computation benefit specific to the area of precision SFF as these systems are traversing through the journey of digitalization and Industry-4.0. Specifically, this article demonstrates that the application of the latest materials modelling approaches, based on techniques such as molecular dynamics, are enabling breakthroughs in applied precision manufacturing techniques.
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    Influence of process parameters on the morphology of spray-dried BaCl2 powders
    (Wiley, 2015-09-24) Taylor Shoulders, W.; Bizarri, Gregory; Bourret, Edith D.; Gaume, Romain M.
    Spray‐drying is an effective method for producing powder aggregates with controlled size and morphology. Here, we report on a systematic study aimed at determining how spray‐drying parameters such as nozzle temperature, gas flow, salt concentration and solution feed rate, influence the characteristics of BaCl2 granules prepared from aqueous solutions. We correlate the granule characteristics to these conditions through the use of processing maps and modeling. It is found that well‐dispersed, high density and spherical aggregates, which are favorable for subsequent powder compaction and sintering, can be obtained within a limited range of processing conditions.
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    Scintillation of tantalate compounds
    (Elsevier, 2018-05-25) Bourret, Edith D.; Smiadak, David M.; Borade, Ramesh B.; Ma, Yunfeng; Bizarri, Gregory; Weber, Marv J.; Derenzo, Stephen E.
    A screening of 63 metal-tantalate-oxides was conducted in search of heavy scintillator materials operating at ambient temperature. While tantalates are known to have slow scintillation decay times, the high atomic number of tantalum (73) provides good stopping power for gamma rays. Screened samples were synthesized by solid state reactions. Scintillation properties of these materials were evaluated by X-ray diffraction, X-ray excited luminescence and pulsed X-ray luminescence. Of the 63 synthesized tantalates examined only 12 had luminosity values greater than 1000 ph/MeV at room temperature. From these, ScTaO4, YTa3O9, and Zn3Ta2O8 have greater than 40% of their emission in the first μs. The brightest and fastest compound of those tested was Zn3Ta2O8 with an estimated luminosity of 26,000 ph/MeV and a main decay time of 600 ns from its crystalline powder. Further attention is given to Zn3Ta2O8 and Mg4Ta2O9 scintillation properties, demonstrating their potential for scintillation applications.
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    Simulation data for heterostructured scintillator development
    (Cranfield University, 2023-03-10 11:17) Bizarri, Gregory; Rogers, Edith; george Krause, Philip; Pei, Qibing; Auffray, Etiennette; Danang Birowosuto, Muhammad; Vasil’ev, Andrey
    Simulation datasets underlying the study 'Design rules for time of flight Positron Emission Tomography (ToF-PET) heterostructure radiation detectors'
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    Supporting data for the article: Advances in design of high-performance heterostructured scintillators for Time-of-Flight Positron Emission Tomography
    (Cranfield University, 2024-04-25 09:12) Bizarri, Gregory
    Data associated with Advances in design of high-performance heterostructured scintillators for Time-of-Flight Positron Emission Tomography
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    Towards the development of Molecularly Imprinted Polymer (MIP) for lineage specific cell surface antigens used in cancer diagnosis.
    (Cranfield University, 2019-10) Sivakumaran, Muttuswamy; Chianella, Iva; Tothill, Ibtisam E.; Bizarri, Gregory
    Immunohistochemistry using antibodies plays a pivotal role in the diagnosis of various solid cancers and haematological malignancies such as leukaemias, lymphomas and myelomas. However, antibodies have a number of disadvantages including its high cost, requirement for refrigeration for transport and storage and its limited shelf life. Hence, the search for a sensitive and specific diagnostic platform that is robust and reproducible and one that utilises a capture ligand which is easy and cheap to manufacture and is stable at room temperature with a long shelf life. Such diagnostic platform would be particularly useful in developing countries, where facilities for storage and transportation at sub-zero temperatures are limited. Molecularly Imprinted Polymers (MIPs), one of the rapidly advancing technologies for nanodiagnostics, may offer such a solution in cancer diagnostics. This exploratory study was undertaken to investigate whether MIP nanoparticles synthesised using the solid-phase approach and epitope imprinting method have potential to replace antibodies in cancer diagnosis. The common leucocyte antigen or CD45 protein which is universally expressed on haemopoietic cells was chosen as the candidate for molecular imprinting because the expression of this antigen can differentiate blood cancers from other neoplasia. In order to make the process cost-effective, a custom-made peptide template with the amino acid sequence that is widely used for anti-CD45 antibody production was used for imprinting. A modification to the amino acid sequence of the template was made by adding the amino acid cysteine which has a thiol group, to the carboxyl end of the CD45 template peptide and anchored to silica nanoparticles to improve the homogeneity of the imprinted polymers. Synthesis of MIPs was carried out using two different compositions of functional monomers, one with a 'standard' mix of monomers and the other one containing a fluorinated monomer. The characterisation of the synthesised nanoMIPs and the binding of the target protein to the MIPs were studied using dynamic light scattering (DLS) and tunable resistive pulse sensing (TRPS). The results of this study prove that the solid-phase synthesis using a custom made polypeptide as the template (segment imprinting) is a logical approach. One important technical refinement is the immobilisation of the template protein to the silica beads in a single orientation via the amino acid cysteine. This modification resulted in the production of more uniform nanoMIPs with low polydispersity. Another significant observation of this study is that the use of fluorinated monomer in combination with the 'standard functional monomers' for the MIP synthesis has improved the quality of the nanoMIPs produced. Furthermore, this study has successfully explored, for the first time, the usefulness and applicability of the technique of tunable resistive pulse sensing (TRPS) for the characterisation of nanoMIPs. The preliminary results obtained in this study indicates that this technique may be superior to dynamic light scattering (DLS) for not only measuring the size and size distribution of the particles but also to study MIP-target interactions. The TRPS analysis of the changes in the zeta potential of the nanoMIPs has shown that the CD45 epitope imprinted nanoMIPs bind to the CD45 protein.
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    Two-dimensional perovskite functionalized fiber-type heterostructured scintillators
    (AIP Publishing, 2023-02-21) Rogers, Edith; Birowosuto, Muhammad Danang; Maddalena, Francesco; Dujardin, Christophe; Pagano, Fiammetta; Kratochwil, Nicolaus; Auffray, Etiennette; Krause, Philip George; Bizarri, Gregory
    A fiber-type heterostructured scintillator based on bismuth germanate (Bi4Ge3O12) functionalized with the 2D-perovskite butylammonium lead bromide ((BA)2PbBr4) has been fabricated, and its scintillation performance analyzed toward its use for fast timing applications such as time-of-flight Positron Emission Tomography. The pixel shows energy sharing between the matrix and filler component, confirming that the two components are in synergy.