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Gravitoelectromagnetism, Cherenkov radiation at finite temperature
摘要： Gravitoelectromagnetism (GEM) is a gravitational theory similar to electromagnetism. The GEM Lagrangian formalism is used to consider a study of the Cherenkov radiation. This allows us to consider the interaction between gravitons and particles that are fermions. The Thermo Field Dynamics (TFD) formalism is used to introduce the temperature effects. The production rate for Cherenkov radiation at finite temperature is calculated.
关键词： finite temperature,Gravitoelectromagnetism,Cherenkov radiation
更新于2025-09-23 15:22:29
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[IEEE 2018 Second International Conference on Electronics, Communication and Aerospace Technology (ICECA) - Coimbatore (2018.3.29-2018.3.31)] 2018 Second International Conference on Electronics, Communication and Aerospace Technology (ICECA) - Patterns Generation of Horizontal Dipole Array Embedded in Different Dielectric Slabs
摘要： A number of papers are available on the analysis of dipole arrays in free space. But the work on embedded dipoles in dielectric media is limited in open literature. The behavior and characteristics are completely changed when the dipoles are embedded in dielectric slab. In this paper horizontal dipole array embedded in different dielectric slabs and different slab thickness is considered. Based on which, and radiation patterns are generated. Such patterns are used in point-to-point communications, scan, and non-scan radar applications.
关键词： Antenna Arrays,Radiation Patterns,Embedded Antennas
更新于2025-09-23 15:22:29
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Solmap: Project In India's Solar Resource Assessment
摘要： India launched Jawaharlal Nehru National Solar Mission in 2009, which aims to set up 20 000 MW of grid connected solar power, besides 2 000 MW equivalent of off-grid applications and cumulative growth of solar thermal collector area to 20 million m2 by 2022. Availability of reliable and accurate solar radiation data is crucial to achieve the targets. As a result of this initiative, Ministry of New and Renewable Energy (MNRE) of Government of India (GoI) has awarded a project to Centre for Wind Energy Technology (C-WET), Chennai in the year 2011 to set up 51 Solar Radiation Resource Assessment (SRRA) stations using the state-of-the-art equipment in various parts of the country, especially the sites with high potential for solar power. The GoI project has synergy with SolMap project, which is implemented by the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) in cooperation with the MNRE. SolMap project is contributing to SRRA project in establishing quality checks on the data obtained as per International protocols and helping data processing to generate investment grade data. The paper highlights the details of SRRA stations and an attempt has been made to present some of the important results of quality control and data analysis with respect to GHI and DNI. While our analysis of the data over one year finds that intensity and profile of the insolation are not uniform across the geographic regions, the variability in DNI is particularly high. Strong influence of monsoon is also identified. SRRA infrastructure aims to develop investment grade solar radiation resource information to assist project activities under the National Solar Mission of India.
关键词： DNI,solar radiation,pyrheliometer,GHI,resource assessment,India
更新于2025-09-23 15:22:29
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Randomized prospective phase III trial of 68Ga-PSMA-11 PET/CT molecular imaging for prostate cancer salvage radiotherapy planning [PSMA-SRT]
摘要： Background: Salvage radiotherapy (SRT) for prostate cancer (PCa) recurrence after prostatectomy offers long-term biochemical control in about 50–60% of patients. SRT is commonly initiated in patients with serum PSA levels < 1 ng/mL, a threshold at which standard-of-care imaging is insensitive for detecting recurrence. As such, SRT target volumes are usually drawn in the absence of radiographically visible disease. 68Ga-PSMA-11 (PSMA) PET/CT molecular imaging is highly sensitive and may offer anatomic localization of PCa biochemical recurrence. However, it is unclear if incorporation of PSMA PET/CT imaging into the planning of SRT could improve its likelihood of success. The purpose of this trial is to evaluate the success rate of SRT for recurrence of PCa after prostatectomy with and without planning based on PSMA PET/CT. Methods: We will randomize 193 patients to proceed with standard SRT (control arm 1, n = 90) or undergo a PSMA PET/CT scan (free of charge for patients) prior to SRT planning (investigational arm 2, n = 103). The primary endpoint is the success rate of SRT measured as biochemical progression-free survival (BPFS) after initiation of SRT. Biochemical progression is defined by PSA ≥ 0.2 ng/mL and rising. The randomization ratio of 1:1.13 is based on the assumption that approximately 13% of subjects randomized to Arm 2 will not be treated with SRT because of PSMA-positive extra-pelvic metastases. These patients will not be included in the primary endpoint analysis but will still be followed. The choice of treating the prostate bed alone vs prostate bed and pelvic lymph nodes, with or without androgen deprivation therapy (ADT), is selected by the treating radiation oncologist. The radiation oncologist may change the radiation plan depending on the findings of the PSMA PET/CT scan. Any other imaging is allowed for SRT planning in both arms if done per routine care. Patients will be followed until either one of the following conditions occur: 5 years after the date of initiation of randomization, biochemical progression, diagnosis of metastatic disease, initiation of any additional salvage therapy, death. Discussion: This is the first randomized phase 3 prospective trial designed to determine whether PSMA PET/CT molecular imaging can improve outcomes in patients with PCa early BCR following radical prostatectomy. Acronym: PSMA-SRT Phase 3 trial.
关键词： Randomized phase 3 trial,PET/CT,Prostate cancer,PSMA,Salvage radiation therapy
更新于2025-09-23 15:22:29
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Optical diffraction radiation from a dielectric and a metal nanowire excited by a modulated electron beam
摘要： The optical diffraction radiation that accompanies the motion of a modulated beam of electrons near a dielectric and silver nanowire scatterers is investigated in the two-dimensional formulation. Our goal is to compute the field in the near and far zones and analyze how it depends on electron beam parameters. We demonstrate the excitation of internal resonances of such a scatterer that can be useful in the design of nanoscale non-invasive beam position monitors.
关键词： Plasmon resonance,Diffraction radiation,Nanowire scatterers,Total scattering cross-section,Absorption cross-section,Smith–Purcell effect,Surface wave
更新于2025-09-23 15:22:29
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Equivalent-Circuit Model with Retarded Electromagnetic Coupling for Meta-Atoms of Wired Metallic Spheres
摘要： This paper describes the equivalent-circuit model of a metamaterial composed of conducting spheres and wires. This model involves electromagnetic coupling between the conductors, with retardation. The lumped-parameter equivalent circuit, which imports retardation to the electromagnetic coupling, is developed in this paper from Maxwell’s equation. Using the equivalent-circuit model, we clarify the relationship between the retardation and radiation loss; we theoretically demonstrate that the electromagnetic retardation in the near-field represents the radiation loss of the meta-atom in the far-field. Furthermore, this paper focuses on the retarded electromagnetic coupling between two meta-atoms; we estimate the changes in the resonant frequencies and the losses due to the distance between the two coupled meta-atoms. It is established that the dependence characteristics are significantly affected by electromagnetic retardation.
关键词： meta-atom,equivalent-circuit model,metamaterial,electromagnetic coupling,radiation,retardation
更新于2025-09-23 15:22:29
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The effects of heating on BaSO4 powders' diffuse reflectance spectra and radiation stability
摘要： BaSO4 powders demonstrate high reflecting capacity in the UV, visible, and near infrared regions of the spectrum and appear to be promising pigments for thermal control coatings of space vehicles and household paints. Their application in a wide range of fields is due to the constant impact of ionizing radiation. In the experiment under study, BaSO4 powders were heated in the atmosphere at T = 100, 400, and 800 °C for the purpose of increasing their radiation stability. It has been established that the highest resistance to accelerated electrons corresponds to the powders preheated at 400 °C. The reflecting capacity of BaSO4 powders after heating at 100 and 400 °C decreases insignificantly. Warming at 800 °C leads to a deterioration in both reflecting capacity and radiation stability compared with the initial powder.
关键词： Barium sulphate,Heating,Radiation stability,Optical properties
更新于2025-09-23 15:22:29
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The CMS Beam Halo Monitor electronics
摘要： The CMS Beam Halo Monitor has been successfully installed in the CMS cavern in LHC Long Shutdown 1 for measuring the machine induced background for LHC Run II. The system is based on 40 detector units composed of synthetic quartz Cherenkov radiators coupled to fast photomultiplier tubes (PMTs). The readout electronics chain uses many components developed for the Phase 1 upgrade to the CMS Hadronic Calorimeter electronics, with dedicated firmware and readout adapted to the beam monitoring requirements. The PMT signal is digitized by a charge integrating ASIC (QIE10), providing both the signal rise time, with few nanosecond resolution, and the charge integrated over one bunch crossing. The backend electronics uses microTCA technology and receives data via a high-speed 5 Gbps asynchronous link. It records histograms with sub-bunch crossing timing resolution and is read out via IPbus using the newly designed CMS data acquisition for non-event based data. The data is processed in real time and published to CMS and the LHC, providing online feedback on the beam quality. A dedicated calibration monitoring system has been designed to generate short triggered pulses of light to monitor the efficiency of the system. The electronics has been in operation since the first LHC beams of Run II and has served as the first demonstration of the new QIE10, Microsemi Igloo2 FPGA and high-speed 5 Gbps link with LHC data.
关键词： Cherenkov and transition radiation,Front-end electronics for detector readout,Beam-line instrumentation (beam position and profile monitors; beam-intensity monitors; bunch length monitors)
更新于2025-09-23 15:22:29
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Fast global orbit feedback system in PLS-II
摘要： The transverse position of the electron beam in the Pohang Light Source-II is stabilized by the global orbit feedback system. A slow orbit feedback system has been operating at 2 Hz, and a fast orbit feedback (FOFB) system at 813 Hz was installed recently. This FOFB system consists of 96 electron-beam-position monitors, 48 horizontal fast correctors, 48 vertical fast correctors and Versa Module Europa bus control system. We present the design and implementation of the FOFB system and its test result. Simulation analysis is presented and future improvements are suggested.
关键词： Instrumentation for particle accelerators and storage rings - high energy (linear accelerators, synchrotrons),Instrumentation for synchrotron radiation accelerators,Accelerator Subsystems and Technologies
更新于2025-09-23 15:22:29
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Generation of High-Power, Reversed-Cherenkov Wakefield Radiation in a Metamaterial Structure
摘要： We present the first demonstration of high-power, reversed-Cherenkov wakefield radiation by electron bunches passing through a metamaterial structure. The structure supports a fundamental transverse magnetic mode with a negative group velocity leading to reversed-Cherenkov radiation, which was clearly verified in the experiments. Single 45 nC electron bunches of 65 MeV traversing the structure generated up to 25 MW in 2 ns pulses at 11.4 GHz, in excellent agreement with theory. Two bunches of 85 nC with appropriate temporal spacing generated up to 80 MW by coherent wakefield superposition, the highest rf power that metamaterial structures ever experienced without damage. These results demonstrate the unique features of metamaterial structures that are very attractive for future high-gradient wakefield accelerators, including two-beam and collinear accelerators. Advantages include the high shunt impedance for high-power generation and high-gradient acceleration, the simple and rugged structure, and a large parameter space for optimization.
关键词： high-power microwaves,reversed-Cherenkov radiation,wakefield acceleration,electron bunches,metamaterial structure
更新于2025-09-23 15:22:29