8 research outputs found
Multi-component low and high entropy metallic coatings synthesized by pulsed magnetron sputtering
This paper presents the findings of the synthesis of multicomponent (Al, W,
Ni, Ti, Nb) alloy coatings from mosaic targets. For the study, a pulsed
magnetron sputtering method was employed under different plasma generation
conditions: modulation frequency (10 Hz and 1000 Hz), and power (600 W and 1000
W). The processes achieved two types of alloy coatings, high entropy and
classical alloys. After the deposition processes, scanning electron microscopy,
X-ray diffraction, and energy-dispersive X-ray spectroscopy techniques were
employed to find the morphology, thickness, and chemical and phase compositions
of the coatings. Nanohardness and its related parameters, namely H3.Er2, H.E,
and 1.Er2H ratios, were measured. An annealing treatment was performed to
estimate the stability range for the selected coatings. The results indicated
the formation of as-deposited coatings exhibiting an amorphous structure as a
single-phase solid solution. The process parameters had an influence on the
resulting morphology-a dense and homogenous as well as a columnar morphology,
was obtained. The study compared the properties of high-entropy alloy (HEA)
coatings and classical alloy coatings concerning their structure and chemical
and phase composition. It was found that the change of frequency modulation and
the post-annealing process contributed to the increase in the hardness of the
material in the case of HEA coatings
Overview of the software architecture and data flow for the J-PET tomography device
Modern TOF-PET scanner systems require high-speed computing resources for efficient data processing, monitoring and image reconstruction. In this article, we present the data flow and software architecture for the novel TOF-PET scanner developed by the J-PET Collaboration. We discuss the data acquisition system, reconstruction framework and image reconstruction software. Also, the concept of computing outside hospitals in the remote centers such as Świerk Computing Centre in Poland is presented
Multiple scattering and accidental coincidences in the J-PET detector simulated using GATE package
Novel Positron Emission Tomography system, based on plastic scintillators, is developed by the J-PET collaboration. In order to optimize geometrical configuration of built device, advanced computer simulations are performed. Detailed study is presented of background given by accidental coincidences and multiple scattering of gamma quanta
Sampling FEE and trigger-less DAQ for the J-PET scanner
In this paper, we present a complete Data Acquisition System (DAQ) together with the readout mechanisms for the J-PET tomography scanner. In general, detector readout chain is constructed out of Front-End Electronics (FEE) measurement devices such as Time-to-Digital or Analog-to-Digital Converters (TDCs or ADCs), data collectors and storage. We have developed a system capable for maintaining continuous readout of digitized data without preliminary selection. Such operation mode results in up to 8 Gbps data stream, therefore, it is required to introduce a dedicated module for on-line event building and feature extraction. The Central Controller Module, equipped with Xilinx Zynq SoC and 16 optical transceivers, serves as such true real time computing facility. Our solution for the continuous data recording (trigger-less) is a novel approach in such detector systems and assures that most of the information is preserved on the storage for further, high-level processing. Signal discrimination applies a unique method of using LVDS buffers located in the FPGA fabric
Preliminary studies of J-PET detector spatial resolution
The J-PET detector, based on long plastic scintillator strips, was recently constructed at the Jagiellonian University. It consists of 192 modules axially arranged into three layers, read out from both sides by digital constant-threshold front-end electronics. This work presents preliminary results of measurements of the spatial resolution of the J-PET tomograph performed with ²²Na source placed at selected position inside the detector chamber
Influence of generation control of the magnetron plasma on structure and properties of copper nitride layers
Application of WLS strips for position determination in strip PET tomograph based on plastic scintillators
A method of the determination of a γ-quantum absorption point in a plastic scintillator block using a matrix of wavelength-shifting (WLS) strips is proposed. An application of this method for the improvement of position resolution in newly proposed positron emission tomography (PET) detectors based on plastic scintillators is presented. The method enables to reduce parallax errors in the reconstruction of images, which occurs in the presently used PET scanners