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The intrinsic radiation spectra of LYSO scintillators are investigated through detailed GEANT4 and SimSiPM simulations, focusing on how changes in configuration and size influence the radiation characteristics. Using these simulation packages together, a comprehensive simulation of the physical processes as well as a detailed simulation of the photodetector response, including factors such as dark count rate, optical crosstalk, afterpulse, noise, and saturation effects, was performed. The results of the simulations indicate that the primary factor affecting the intrinsic radiation pattern is the total volume of the crystal, rather than surface treatments or minor geometric variations. The consistency between GEANT4 and SimSiPM simulations confirms the validity of using these simulation methods to analyze the spectral behavior of LYSO scintillators detailed in various applications such as positron emission tomography and nuclear spectroscopy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Although porous anodized aluminum oxide layer can be used to extract scintillation light from a LYSO scintillator, the low refractive index contrast of porous AAO layer obtains a moderate enhancement. In this investigation, we have designed and fabricated a modified porous anodized aluminum oxide layer with conformal deposition layer of high refractive index material of TiO 2 on the surface of LYSO scintillator, achieving a significant enhancement by 60% with wavelength- and angle-integrated emission intensity. The fabrication method of the present study is simple and low-cost for the large area applications in the field of radiation detection. [ABSTRACT FROM AUTHOR]

As a promising scintillator in the field of medical imaging systems, LYSO with its high refractive index suffers from a low light extraction efficiency due to the total internal reflection. Here, we demonstrate that a photonic structure formed by an anodized aluminum oxide layer can enhance the light extraction efficiency by the outcoupling the light trapped in the crystal. An enhancement of light output by 25% can be achieved by an AAO layer covered on the surface of LYSO. The imperfect periodicity of AAO can lead to a consistent enhancement for the entire range of emission wavelength and directionality. Such enhanced light output is practical and attractive for use in the scintillation detection systems. It is important to note that the fabrication method of AAO is simple and low-cost for the large area applications, which is obviously advantageous over the expensive traditional methods such as electron beam lithography. [ABSTRACT FROM AUTHOR]

Abstract: AX-PET stands for a new geometrical concept for a high resolution and high sensitivity PET scanner, based on an axial arrangement of long scintillating crystals in the tomograph, for a parallax free PET detector. Two identical AX-PET modules – consisting of matrices of LYSO crystals interleaved with WLS strips – have been built. They form the AX-PET Demonstrator, which has been extensively characterized and successfully used for the reconstruction of images of several phantoms. In this paper we report on the current status of the project, with emphasis on the most relevant results achieved both in terms of detector characterization and image reconstruction. We also discuss the recent preliminary results obtained with the digital SiPM from Philips (dSiPM), which are currently being tested as a possible alternative photodetector for AX-PET. With their very good intrinsic time resolution, dSiPM could add Time of Flight capability to the AX-PET concept. [Copyright &y& Elsevier]

One of the main factors limiting the precision of timing measurements with silicon photomultipliers coupled to scintillators is the dark noise, especially in the case of large devices. In order to cope with it, a suitable signal processing should be employed. The method we propose is called differential leading edge discriminator (DLED) and allows an effective compensation of the baseline fluctuations due to the dark counts of the detector. In this paper we show a comparison between the measurements obtained using the traditional Leading Edge Discriminator technique and the DLED. The improvement we observe is remarkable. Combining this baseline correction algorithm with low temperatures, we were able to reach a coincidence resolving time of 180 ps FWHM, using 4 mm \times\,4 mm SiPMs produced at FBK coupled to 3.8 mm \times\,3.8 mm \times\,5 mm Teflon-wrapped LYSO crystals. [ABSTRACT FROM AUTHOR]

Abstract: The use of Silicon Photo-Multipliers (SiPMs) as photon detectors in Positron Emission Tomography (PET) modules offers significant advantages over conventional light sensors, including application in a magnetic field, better resolution and easier operation. Different types of SiPMs have been tested: Photonique, 2.1×2.1mm2, Hamamatsu 3×3mm2 and STMicroelectronics 3.5×3.5mm2. Dark noise, surface sensitivity, photon detection efficiency and linearity at low light intensities have been measured. A LYSO crystal was coupled to a SiPM to test the performance as a photon detector for PET. We will present the results of the measurements for different samples and types. [ABSTRACT FROM AUTHOR]

Abstract: The possibility of background suppression by spatial and time discrimination of events stipulates the potentialities of the nanosecond tagged neutron technology (NTNT) for neutron analysis. For practical application of NTNT, the multi-detector systems and high intensity (up to 1×108 1/s) neutron generator should be used. The total intensity of signals can exceed 1×106 1/s from all gamma-detectors and 1×107 1/s from all alpha-detectors. A preliminary “on-line” data processing by hardware sufficiently facilitates the data transmission interface and computer equipment. The basic criteria of processing (selection of useful events) are the presence of signals from alpha- and gamma-detectors in the certain time interval (tracking interval), range of gamma-ray energy and absence of foldover of the signals. The suggested architecture of data acquisition and control system is discussed. The basic components of background and factors affecting the total time resolution are examined. The preliminary results demonstrate high efficiency of NTNT for suppression of background by spatial and time discrimination of events. [Copyright &y& Elsevier]

Abstract: A novel photon detector, the Silicon Photomultiplier (SiPM), has been tested in view of a photosensitive device for Positron Emission Tomography (PET), which is one of the most important non-invasive methods for in-depth and in vivo imaging of tissue. Such a device offers advantages over existing ones, including application in a magnetic field, better resolution and easier operation. Two PET modules have been constructed by coupling an array of Hamamatsu 3mm×3mm Multi-pixel photon Counters (MPPCs) and Photonique 2.2mm×2.2mm Solid-state Photomultipliers (SSPMs) to LYSO scintillation crystals. The results of studies of the two module prototypes are presented. [ABSTRACT FROM AUTHOR]

Abstract: The AX-PET is a new geometrical concept for a high resolution 3D PET scanner, based on matrices of axially oriented LYSO crystals interleaved by stacks of WLS, both individually read out by G-APDs. A PET demonstrator, based on two detector modules used in coincidence, is currently under construction. [Copyright &y& Elsevier]