3-D localization of radioactive hotspots via portable gamma cameras Paradiso, V.; Amgarou, K.; de Lanaute, N. Blanc ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2018, Letnik:
910
Journal Article
Recenzirano
A portable stereo gamma camera has been built, based on two hybrid pixelated detectors, each of them comprising a 1 mm thick CdTe substrate bump-bonded to the Timepix readout chip, a pixelated CMOS ...ASIC consisting of 256 × 256 pixels with 55µm pitch.
The technique described in this paper allows the automatic estimation of the distances between the prototype and the located radioactive sources by using triangulation based on epipolar geometry. The 3-D Cartesian coordinates of the sources are provided even when they are hidden behind an occluding material, such as a wall, or inside a barrel. Furthermore, the combination of the prototype with a depth sensor enables a wide range of applications, including the 3-D volumetric reconstruction of the scene under study as well as the capability of autonomously determining if an object is occluding the located radioactive sources.
We discuss here the main features of the whole methodology developed and we also present the experimental results obtained at laboratory scale.
The Short-Baseline Near Detector time projection chamber is unique in the design of its charge readout planes. These anode plane assemblies (APAs) have been fabricated and assembled to meet strict ...accuracy and precision requirements: wire spacing of 3 mm ± 0.5 mm and wire tension of 7 N ± 1 N across 3,964 wires per APA, and flatness within 0.5 mm over the 4 m × 2.5 m extent of each APA . This paper describes the design, manufacture and assembly of these key detector components, with a focus on the quality assurance at each stage.
A known disadvantage of the coded aperture imaging approach is its limited field-of-view (FOV), which often results insufficient when analysing complex dismantling scenes such as post-accidental ...scenarios, where multiple measurements are needed to fully characterize the scene. In order to overcome this limitation, a panoramic coded aperture γ-camera prototype has been developed. The system is based on a 1 mm thick CdTe detector directly bump-bonded to a Timepix readout chip, developed by the Medipix2 collaboration (256×256 pixels, 55 μm pitch, 14.08×14.08 mm2 sensitive area). A MURA pattern coded aperture is used, allowing for background subtraction without the use of heavy shielding. Such system is then combined with a USB color camera. The output of each measurement is a semi-spherical image covering a FOV of 360 degrees horizontally and 80 degrees vertically, rendered in spherical coordinates (θ,φ). The geometrical shapes of the radiation-emitting objects are preserved by first registering and stitching the optical images captured by the prototype, and applying, subsequently, the same transformations to their corresponding radiation images. Panoramic gamma images generated by using the technique proposed in this paper are described and discussed, along with the main experimental results obtained in laboratories campaigns.
The ICARUS collaboration employed the 760-ton T600 detector in a successful 3-year physics run at the underground LNGS laboratory, performing a sensitive search for LSND-like anomalous
ν
e
appearance ...in the CERN Neutrino to Gran Sasso beam, which contributed to the constraints on the allowed neutrino oscillation parameters to a narrow region around 1 eV
2
. After a significant overhaul at CERN, the T600 detector has been installed at Fermilab. In 2020 the cryogenic commissioning began with detector cool down, liquid argon filling and recirculation. ICARUS then started its operations collecting the first neutrino events from the booster neutrino beam (BNB) and the Neutrinos at the Main Injector (NuMI) beam off-axis, which were used to test the ICARUS event selection, reconstruction and analysis algorithms. ICARUS successfully completed its commissioning phase in June 2022. The first goal of the ICARUS data taking will be a study to either confirm or refute the claim by Neutrino-4 short-baseline reactor experiment. ICARUS will also perform measurement of neutrino cross sections with the NuMI beam and several Beyond Standard Model searches. After the first year of operations, ICARUS will search for evidence of sterile neutrinos jointly with the Short-Baseline Near Detector, within the Short-Baseline Neutrino program. In this paper, the main activities carried out during the overhauling and installation phases are highlighted. Preliminary technical results from the ICARUS commissioning data with the BNB and NuMI beams are presented both in terms of performance of all ICARUS subsystems and of capability to select and reconstruct neutrino events.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The Short-Baseline Near Detector time projection chamber is unique in the design of its charge readout planes. These anode plane assemblies (APAs) have been fabricated and assembled to meet strict ...accuracy and precision requirements: wire spacing of 3 mm ± 0.5 mm and wire tension of 7 N ± 1 N across 3,964 wires per APA, and flatness within 0.5 mm over the 4 m × 2.5 m extent of each APA . This paper describes the design, manufacture and assembly of these key detector components, with a focus on the quality assurance at each stage.
ATLAS is one of the four large experiments at the Large Hadron Collider at CERN. The detector itself and the surrounding structures in the cavern of the experiment are accessible for people during ...maintenance periods. People can easily be isolated and difficult to localize in which case their safety may be compromised in this very complex environment. Therefore a dedicated system called ¿Finding Persons Inside ATLAS Areas¿ has been designed and implemented to track persons in the experimental cavern. It is based on a network of passive infrared sensors which are read out by specific front-end electronics. A complex software architecture provides active tracking of people in the cavern with the possibility to detect abnormal situations where people are possibly in danger. This paper describes the technological choices which have been made for this monitoring system and explains the implementation of the software components. This provides a tool for the operation in the control room of ATLAS to actively follow people in the cavern underground. As the system is data-driven, it can be easily adapted to other environments where similar safety problems exist.
The Short-Baseline Near Detector time projection chamber is unique in the design of its charge readout planes. These anode plane assemblies (APAs) have been fabricated and assembled to meet strict ...accuracy and precision requirements: wire spacing of 3 mm +/- 0.5 mm and wire tension of 7 N +/- 1 N across 3,964 wires per APA, and flatness within 0.5 mm over the 4 m +/- 2.5 m extent of each APA. This paper describes the design, manufacture and assembly of these key detector components, with a focus on the quality assurance at each stage.
Background and purpose
Biomarkers support the aetiological diagnosis of neurocognitive disorders in vivo. Incomplete evidence is available to drive clinical decisions; available diagnostic algorithms ...are generic and not very helpful in clinical practice. The aim was to develop a biomarker‐based diagnostic algorithm for mild cognitive impairment patients, leveraging on knowledge from recognized national experts.
Methods
With a Delphi procedure, experienced clinicians making variable use of biomarkers in clinical practice and representing five Italian scientific societies (neurology – Società Italiana di Neurologia per le Demenze; neuroradiology – Associazione Italiana di Neuroradiologia; biochemistry – Società Italiana di Biochimica Clinica; psychogeriatrics – Associazione Italiana di Psicogeriatria; nuclear medicine – Associazione Italiana di Medicina Nucleare) defined the theoretical framework, relevant literature, the diagnostic issues to be addressed and the diagnostic algorithm. An N–1 majority defined consensus achievement.
Results
The panellists chose the 2011 National Institute on Aging and Alzheimer's Association diagnostic criteria as the reference theoretical framework and defined the algorithm in seven Delphi rounds. The algorithm includes baseline clinical and cognitive assessment, blood examination, and magnetic resonance imaging with exclusionary and inclusionary roles; dopamine transporter single‐photon emission computed tomography (if no/unclear parkinsonism) or metaiodobenzylguanidine cardiac scintigraphy for suspected dementia with Lewy bodies with clear parkinsonism (round VII, votes (yes‐no‐abstained): 3‐1‐1); 18F‐fluorodeoxyglucose positron emission tomography for suspected frontotemporal lobar degeneration and low diagnostic confidence of Alzheimer’s disease (round VII, 4‐0‐1); cerebrospinal fluid for suspected Alzheimer’s disease (round IV, 4‐1‐0); and amyloid positron emission tomography if cerebrospinal fluid was not possible/accepted (round V, 4‐1‐0) or inconclusive (round VI, 5‐0‐0).
Conclusions
These consensus recommendations can guide clinicians in the biomarker‐based aetiological diagnosis of mild cognitive impairment, whilst guidelines cannot be defined with evidence‐to‐decision procedures due to incomplete evidence.
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