The TexAT (Texas Active Target) detector is a new active-target time projection chamber (TPC) that was built at the Cyclotron Institute Texas A&M University. The detector is designed to be of general ...use for nuclear structure and nuclear astrophysics experiments with rare isotope beams. TexAT combines a highly segmented Time Projection Chamber (TPC) with two layers of solid state detectors. It provides high efficiency and flexibility for experiments with low intensity exotic beams, allowing for the 3D track reconstruction of the incoming and outgoing particles involved in nuclear reactions and decays.
The effect of temperature and degree of deformation upon severe plastic deformation by torsion under a high pressure on the structure, phase composition, and microhardness of the industrial zirconium ...Zr–1% Nb alloy (E110) has been studied. The high-pressure torsion (HPT) (with
N
= 10 revolutions) of the Zr–1% Nb alloy at room temperature results in the formation of grain–subgrain nanosize structure with an average size of structural elements of 65 nm, increase in the microhardness by 2.3–2.8 times (to 358 MPa), and α-Zr → β-Zr and α-Zr → ω-Zr phase transformations. The increase in the HPT temperature to 200°C does not lead to a decrease in the microhardness of alloy owing to the increase in the fraction of ω-Zr phase, though the average size of structural elements increases to 125 nm. The increase in the temperature to 400°C during HPT with
N
= 10 revolutions leads to the grain growth in the α-Zr grain structure (~90%) to 160 nm and a decrease in the microhardness to 253–276
HV
.
Deep learning has been employed in various scientific fields and has provided promising results. In this study, a deep learning classifier was implemented to improve the quality of data obtained from ...a time projection chamber. Digital waveforms of the detected signals were classified into the following three categories: particles, noises, and particles piled up with noises. A simple 1-dimensional convolutional neural network was developed for the classification. The model demonstrated an excellent performance on the test dataset. Its practical performance was also examined using track images and particle identification plots by comparing the original and clean data without the noise signals. The comparison clearly showed that the deep learning model improved the quality of data. The current study presents an effective application of the deep learning model for the time projection chamber data.
A spray solution combustion synthesis method has been developed to produce hollow spherical metal nanostructured particles. In this approach, combustion reactions in the liquid solution contribute ...100% of the overall energy released during the synthesis process without the involvement of an external gaseous flame. It has been shown that this method is effective for the synthesis of spherical hollow particles of metals (Ni, Cu) with an average diameter of about 3 μm and wall thicknesses of about 20 nm.
Restoring original signals from pile-up using deep learning Kim, C.H.; Ahn, S.; Chae, K.Y. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
October 2023, 2023-10-00, 2023-10-01, Letnik:
1055, Številka:
C
Journal Article
Recenzirano
Pile-up signals are frequently produced in experimental physics. They create inaccurate physics data with high uncertainties and cause multiple problems. Therefore, the correction of pile-up signals ...is crucially required. In this study, we implemented a deep learning method to restore the original signals from signals piled up with unwanted signals. We showed that a deep learning model could accurately reconstruct the original signal waveforms from the pile-up waveforms. By substituting the pile-up signals with the original signals predicted by the model, the energy and timing resolution of the data are notably enhanced. The model implementation significantly improved the quality of the particle identification plot and particle tracks. This method is applicable to similar problems, such as separating multiple signals or correcting pile-up signals with other types of noises and backgrounds.
The nuclear structure of 19F and 19Ne is important for understanding of α clustering in the A=20 mass region and in questions related to astrophysics. However, the only high-resolution broad angular ...and energy range study of the 19F resonance structure in α+15N scattering was published over 60 years ago, and a detailed analysis of complex excitation functions of overlapping resonances with several decay channels was simply impossible at that time. We performed a modern R-matrix analysis of these old data to assign spins and specify resonant parameters of levels up to excitation energy of 8.2 MeV in 19F. We successfully tested our R-matrix parameters in a fit of the recent data on α+15N obtained by thick target inverse kinematics (TTIK) method at 180 degrees. We used the new parameters for 19F to fit TTIK data for α+15O, the mirror resonant reactions. The comparison of the data for isobaric mirror resonant reactions provides an interesting insight into the nuclear structure.
A position and pulse shape discriminant p-terphenyl detector module Scriven, D.P.; Christian, G.; Rogachev, G.V. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2021, Letnik:
1010
Journal Article
Recenzirano
Odprti dostop
We present the development of a neutron detector array module made with para-terphenyl, a bright, fast, n/γ discriminating crystalline organic scintillator. The module is comprised of 2 cm × 2 cm × ...2 cm p-terphenyl crystals that have been optically coupled together to create a pseudo-bar module. While only relying on two photo detectors, the module is capable of distinguishing interactions between up to eight crystals. Furthermore, the module retains the p-terphenyl’s pulse shape discrimination (PSD) capability. Together this makes the pseudo-bar module a promising position-sensitive neutron detector. Here we present characteristics of the pseudo-bar module — its timing resolution as well as its pulse shape and position discrimination capabilities, and briefly discuss future plans for utilizing an array of pseudo-bar modules in a useful neutron detector system.
The structure of the Hoyle state, a highly α -clustered state at 7.65 MeV in 12C, has long been the subject of debate. Understanding if the system comprises of three weakly interacting α particles in ...the 0s orbital, known as an α-condensate state, is possible by studying the decay branches of the Hoyle state. The direct decay of the Hoyle state into three α particles, rather than through the 8Be ground state, can be identified by studying the energy partition of the three α particles arising from the decay. This paper provides details on the breakup mechanism of the Hoyle stating using a new experimental technique. Method: By using β-delayed charged-particle spectroscopy of 12N using the Texas active target time-projection chamber, a high-sensitivity measurement of the direct 3α decay ratio can be performed without contributions from pileup events. A Bayesian approach to understanding the contribution of the direct components via a likelihood function shows that the direct component is <0.043% at the 95% confidence level. This value is in agreement with several other studies, and, here, we can demonstrate that a small nonsequential component with a decay fraction of about 10–4 is most likely. Here, the measurement of the non-sequential component of the Hoyle state decay is performed in an almost medium-free reaction for the first time. The derived upper limit is in agreement with previous studies and demonstrates sensitivity to the absolute branching ratio. Further experimental studies would need to be combined with robust microscopic theoretical understanding of the decay dynamics to provide additional insight into the idea of the Hoyle state as an α condensate.
Results of experiments aimed at amplification of the pressure of laser-induced shock wave on the passage from low- to high-density target material via vacuum gap are presented. During the action of ...nanosecond laser pulse of terawatt power on plane composite targets comprising a layer of laser radiation absorber of low-density (0.01–0.025 g/cm
3
) spaced by vacuum gap from a layer of aluminum, the shock-wave velocity in aluminum reached 25–29 km/s and a pressure jump at the aluminum layer boundary was 1.2–1.5 times as large as that observed in experiments on the cumulative transition of laser-induced shock wave into a solid. The obtained experimental data are compared to results of the numerical calculations performed using hydrodynamic programs in which the shock-wave generation and propagation was modeled with allowance for the interaction of laser pulses with partly homogenized plasma of the porous material. Based on the results of experiments, numerical calculations, and their theoretical analysis, the efficiency of using low-density porous media in the targets intended for their equation of state investigations and inertial confinement fusion ignition is considered.
We report on the results of experiments performed on the Iskra-5 laser facility for studying the effect of the polydeuteroethylene (CD
2
)
n
working layer thickness on the operation parameter of an ...inverted-corona target. In all experiments of this series, the neutron yield at a level of 10
7
–3 × 10
8
DD neutrons per shot was detected for the total laser radiation energy supplied to the target by 12 second-harmonic beams in the range of 1.6–2.2 kJ. Using the neutron time-of-flight technique, we have detected an increase in the ion temperature from approximately 6.4 to 14 keV upon a decrease in the (CD
2
)
n
layer thickness from 1 to 0.1 μm.
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