Ex) Article Title, Author, Keywords
pISSN 0374-4914
eISSN 2289-0041
pISSN 0374-4914
eISSN 2289-0041
Ex) Article Title, Author, Keywords
Abstract : In this study, we explore the spectral discrimination of fluorescence images of liquid scintillators acquired by complementary metal oxide semiconductor (CMOS) image sensors using the discriminative ability of deep convolutional neural networks without requiring any special effort. With the continuous advancement of semiconductor fab-processing technology, the processing technology of optical elements in image sensors has also advanced. However, there exists a trade-off between the pixel size of an image sensor, signal noise ratio, and high color reproduction. Furthermore, commercial CMOS image sensor manufacturers typically do not provide users with spectral response data for their CMOS sensors. To address these challenges, we generated training images using a light-emitting diode module programmable on a single-board computer and demonstrated the feasibility of inferring the spectral response backward from the discriminant values of a deep convolutional neural network. Building on the previous study and considering the operational characteristics of neutrino experiments, we evaluated the feasibility of employing a deep convolutional neural network for monitoring the attenuation distance and spectral response of light in a liquid scintillator through supervised learning. In future, we aim to optimize transformer implantation that is efficient with limited required computational resources for the characteristics of the Internet of Things.
Abstract : The optical properties of white light-emitting diodes (LEDs) with a yellow phosphor plate and a red quantum dot film applied sequentially on top of a blue LED chip were investigated as a function of phosphor thickness, quantum dot concentration, and the presence or absence of the microprism film. It was found that an excessively thick yellow phosphor plate leads to an increased absorption of the blue LED, resulting in a higher proportion of yellow light and deviation from the Planckian locus. This deviation arises due to the absence of long-wavelength red component in the emitting spectrum of yellow phosphor plates. Particularly, the application of one-dimensional microprism film to the quantum dot film demonstrates notable enhancement. The reflection at the prism interface facilitates the reciprocating motion of light within the vertical cavity formed by the prism film and the bottom reflector. This phenomenon considerably increases the color conversion efficiency of the red quantum dot film, resulting in improved on-axis brightness and color rendering index. This study provides insights into improving the color rendering performance of lighting with remote color-changing components.
Abstract : The structure of physics education research papers was explored by analyzing and comparing empirical research papers from academic fields closely related to physics education research. A total of 100 papers were studied, including 20 studies each in physics, chemistry, education, and psychology, all of which were recently published in Korean journals. According to the results, IM[RD]C for physics and chemistry, ILMR[DC] for education, and IMRD for psychology were the most common. However, structural patterns in physics education were found to be diverse. Moreover, titles such as “Conclusions and suggestions” toward the end of the paper was identified as a characteristic trait of physics education papers as it was rarely observed in other fields. As in education, tables were used more often than pictures and the characteristics of natural and social science research articles appeared complex in physics education papers. Furthermore, some characteristics were unique to physics education papers.
Abstract : We provide an intuitive illustration of the working principle of fiber-optic optical delay lines constructed with linearly chirped fiber gratings (LCFBG). We accomplish this by employing reflected-wavelength characteristic graphs. This graph depicts the reflected wavelength based on the internal position of the LCFBG. The LCFBG is an optical device used for dispersion compensation in optical communication and it features optical delay characteristics that rely on the reflected wavelength. By utilizing the reflected-wavelength characteristic graph, we can visually explain the amplification effect of the optical path difference caused by stretching one of the two LCFBGs in the optical delay line. Additionally, the dependence of the amplification effect on the center wavelength and reflected spectral bandwidth of the LCFBG was also understood using the reflected-wavelength characteristic graph. The proposed method aims to aid in comprehending the characteristics of fiber-optic optical delay lines using LCFBGs, as well as the operating principles and features of various LCFBGs-based applications.
Abstract : This study aims to prove six figures and equations presented in Newton's and to analyze their meaning. Newton's figures of refraction (equations) can be divided into three parts. The first is a situation where light rays parallel to the optical axis converge at a point after refraction. If the refractive index of the medium before refraction is greater than the refractive index of the medium after refraction, it becomes a hyperbolic surface; in the opposite case, it turns out to be an ellipsoid surface. This situation represents a lens with no spherical aberration. The second is the refraction of a ray traveling at an arbitrary angle, which can be interpreted in relation to `exact ray tracing'. The third shows that a ray departing from a point on the optical axis travels to a point on the optical axis after being refracted; when paraxial ray conditions are applied, it can be expressed as the `Gauss formula for a single refracting surface'. Additionally, this study discusses potential applications to university optics education.
Abstract : In this study, hexagonal Cd1-xMnxS (h-CdMnS) thin films with different Mn compositions were grown on GaAs(111) substrates using hot-wall epitaxy. The energy gap of the grown films was obtained through the reflection spectrum, and the crystal structure and quality were examined through X-ray diffraction (XRD) and high-resolution XRD. To obtain insights into the spectroscopic characteristics of the grown films, spectroscopic ellipsometry (SE) was employed, and the critical structures were identified. The pseudodielectric constants ε1(E) and ε2(E) were derived from the obtained critical structures. Additionally, using the second derivatives of the pseudodielectric constants, the variation of critical structures was analyzed as a function of Mn composition. In particular, the energy bandgap (Eg) obtained from the reflection spectrum and the energy bandgap (E0) obtained from SE measurements were compared and analyzed for the h-CdMnS/GaAs(111).
Abstract : Compared to bulk Si, Si quantum dots (SiQDs)-embedded SiO2 (SiQDs:SiO2) is a promising material for photodetector (PD) devices owing to its exceptional light absorption and fast light response properties in the visible region. In this study, we successfully fabricated PDs by inserting a hexagonal boron nitride (h-BN) interlayer into (trifluoromethanesulfonyl)-amide (TFSA)-doped graphene/SiQDs:SiO2/n–Si heterojunction structure. The TFSA-doped graphene/SiQDs:SiO2/n–Si PD exhibits a broadband photoresponse behavior at 0 V. The insertion of the h-BN layer between TFSA-doped graphene and SiQDs:SiO2 effectively suppressed carrier recombination at the interface, leading to a significant reduction in the dark current. Consequently, the detectivity of the h-BN-based PD increased by four times compared to the device without h-BN.
Abstract : In this study, we examined the magnetic field–induced dynamic change of magnetic domains in Co/Ni nanomagnetic wires, focusing on the effects of the underlayer type and thickness. Real-time domain observation was performed using a magneto-optic Kerr effect microscope, enabling the analysis of the changes in domain dynamics. The underlayers of Co/Ni magnetic wires were composed of Pt and Au with varying thicknesses. The Pt thickness was varied from 2.5 Å to 10 Å, and the thickness of Au was varied from 15 Å to 50 Å. First, the magnetization reversal of all samples exhibited a tendency of domain wall movement, with increasing coercivity for increasing underlayer thickness. Furthermore, by analyzing the domain wall velocity data for the magnetic field magnitude, it was confirmed that the domain wall movement in all samples could be effectively explained by the thermal activation model based on the domain wall creep motion. Additionally, we found that the magnetic field strength required magnetic domain wall movement increased with increasing underlayer thickness.
Abstract : In this study, we developed two types of electroluminescent (EL) devices. One type was made solely of ZnS:(Cu, Al, Mn) composite and the other type was a mixture of the ZnS:(Cu, Al, Mn) and ZnS:(Cu, Cl) composites. The light-emitting device was fabricated by mixing ZnS phosphor and polydimethylsiloxane between two indium tin oxide glasses. When the ZnS:(Cu, Cl) composites were added to the ZnS:(Cu, Al, Mn) composites, the intermixed EL device emitted brighter light than the device fabricated with only the ZnS:(Cu, Al, Mn) composite at the same bias and frequency. The International Commission on Illumination color coordinates of the EL devices produced with only the ZnS:(Cu, Al, Mn) composites and with the intermixed ZnS:(Cu, Al, Mn) phosphors and ZnS:(Cu, Cl) composites were (0.30, 0.40) and (0.24, 0.42), respectively, at 100 Hz. These values changed to (0.28, 0.31) and (0.23, 0.32), respectively, at 500 Hz. We believe that the ZnS EL device composed of the two mixed composites could be utilized as an illumination light source for large-area displays, which, in turn, require active color expression.
Abstract : The development and application of kinematic variables for studying the decay of particle pairs into partially undetected final states are not limited to high-energy collider experiments. Similar challenges may arise in flavor physics experiments such as Belle and LHCb. In scenarios where the signal and tag parent particles decay semi-invisibly, identifying the signal becomes challenging because of the lack of knowledge of the signal-parent boost. To address this problem, kinematic variables such as M2 have been specifically designed for pairwise decays into visible and invisible particles and can be effectively used. Based on this observation, several kinematic quantities have been developed to separate the signal from background and tested in benchmark searches for τ and B decays at Belle and Belle II.
Abstract : It is crucial to verify the beam trajectory in various particle accelerators used in experiments and diagnostics, both domestically and internationally, to determine whether the beam has reached the intended location. In this study, a prototype beam drift chamber (pBDC) was designed and manufactured using a gaseous drift chamber-type detector to reconstruct the beam trajectory. The pBDC will be used for the performance testing of real BDC for reconstructing the beam trajectory irradiated from the front of the beam line toward the target of the Large Acceptance Multi-Purpose Spectrometer (LAMPS). LAMPS is currently under construction for nuclear symmetry energy research at the Rare Isotope Accelerator complex for ON-line experiments in Daejeon, Republic of Korea. This paper describes the pBDC structure and performance test results obtained by measuring the drift velocity of the pBDC using 100-MeV proton beam produced by the HIMAC facility located in Japan.
Abstract : We address a subtle confusion that may arise when dealing with two-dimensional elastic collision problems in college-level physics education as the problem apparently provides fewer equations than the number of unknowns. We point out that the confusion originates from the misconception that this collision problem involving two mass points is similar to that involving several bulky objects. In addition, the relevant chapter in most textbooks is presented before introducing the concept of angular momentum and its conservation law. Nevertheless, we address and clarify this confusion by showing that the exact solutions to the problem can be obtained by considering the impact parameter in the collision process.
Abstract : In this study, we explore the spectral discrimination of fluorescence images of liquid scintillators acquired by complementary metal oxide semiconductor (CMOS) image sensors using the discriminative ability of deep convolutional neural networks without requiring any special effort. With the continuous advancement of semiconductor fab-processing technology, the processing technology of optical elements in image sensors has also advanced. However, there exists a trade-off between the pixel size of an image sensor, signal noise ratio, and high color reproduction. Furthermore, commercial CMOS image sensor manufacturers typically do not provide users with spectral response data for their CMOS sensors. To address these challenges, we generated training images using a light-emitting diode module programmable on a single-board computer and demonstrated the feasibility of inferring the spectral response backward from the discriminant values of a deep convolutional neural network. Building on the previous study and considering the operational characteristics of neutrino experiments, we evaluated the feasibility of employing a deep convolutional neural network for monitoring the attenuation distance and spectral response of light in a liquid scintillator through supervised learning. In future, we aim to optimize transformer implantation that is efficient with limited required computational resources for the characteristics of the Internet of Things.
Abstract : The ALICE (A Large Ion Collider Experiment) pixel detector is a silicon detector based on the Monolithic Active Pixel Sensor technology specifically designed for use in the Inner Tracking System of the ALICE and other collider experiments. A charge threshold scan over whole pixels with varying radiation doses is a standard procedure for the total ionizing dose effect study to assess the radiation hardness of the sensor. This procedure was performed using the Korea Multi-purpose Accelerator Complex proton beam. During the charge threshold scan procedure, some anomalous reading failures are observed depending on the positions of the pixels within a chip. In this study, we examine the underlying reasons for these failures under various conditions, which involve using a radiation source and modifying the scan procedures. This paper presents comprehensive results and discusses the possible failures caused by incident particles from radiated materials near the pixels.
Abstract : The optical properties of white light-emitting diodes (LEDs) with a yellow phosphor plate and a red quantum dot film applied sequentially on top of a blue LED chip were investigated as a function of phosphor thickness, quantum dot concentration, and the presence or absence of the microprism film. It was found that an excessively thick yellow phosphor plate leads to an increased absorption of the blue LED, resulting in a higher proportion of yellow light and deviation from the Planckian locus. This deviation arises due to the absence of long-wavelength red component in the emitting spectrum of yellow phosphor plates. Particularly, the application of one-dimensional microprism film to the quantum dot film demonstrates notable enhancement. The reflection at the prism interface facilitates the reciprocating motion of light within the vertical cavity formed by the prism film and the bottom reflector. This phenomenon considerably increases the color conversion efficiency of the red quantum dot film, resulting in improved on-axis brightness and color rendering index. This study provides insights into improving the color rendering performance of lighting with remote color-changing components.
Geun Taek YU, Geun Hyeong PARK, Eun Been LEE, Min Hyuk PARK*
New Phys.: Sae Mulli 2021; 71(11): 890-900
https://doi.org/10.3938/NPSM.71.890
Aekyung Shin, Donggeul Hyun, Jeongwoo Park
New Phys.: Sae Mulli 2023; 73(1): 37-43
https://doi.org/10.3938/NPSM.73.37
Chang Won AHN, Jin San CHOI, Muhammad SHEERAZ, Hwan Min KIM, Ill Won KIM, Tae Heon KIM*
New Phys.: Sae Mulli 2021; 71(12): 991-1003
https://doi.org/10.3938/NPSM.71.991
pISSN 0374-4914
