Synchrotron Radiation Spectrum Research Articles

Aharonov-Bohm experiments in magnetic field without the Landau levels

We discuss the two-slit experiment and the Aharonov-Bohm (AB) experiment in the magnetic field, where an electron produces so called synchrotron radiation. In other words, the photons are emitted from the points of the electron trajectory and it means that the trajectory of electron is visible in the synchrotron radiation spectrum. The axiomatic system of quantum mechanics does not enable to define the trajectory of the elementary particle. The two-slit experiment and the AB experiment in magnetic field are the missing experiments of quantum mechanics. The extension of the discussion to the cosmical rays moving in the magnetic field of the Saturn magnetosphere and its rings is mentioned. It is related to the probe CASSINI.

Non-Destructive Single-Revolution Electron Beam Profilometer based on a CCD Camera

CCD cameras are easy to use and are quite widespread in the optical diagnostics of beams in particle accelerators. The exposure time of these cameras is milliseconds, so they are usually used in a cumulative mode to monitor the circulating beams. The images from the cameras contain information about the transverse distribution of particles in the beam and the position of the center of mass of the beam. In this paper, using the example of CCD cameras installed on the electron-positron collider VEPP-2000, the possibility of their use in the mode of a single beam flight through the observation site is investigated. The intensity of the luminous flux of the optical part of the synchrotron radiation spectrum of the beam was estimated and an image of the transverse distribution of particles in the beam in a single-span mode was experimentally obtained, which confirms the potential for expanding the scope of this diagnostic system. A trial signal processing was done as a demonstration of the determination of the beam parameters by the method under study.

CLASS Angular Power Spectra and Map-component Analysis for 40 GHz Observations through 2022

Measurement of the largest angular scale (ℓ < 30) features of the cosmic microwave background (CMB) polarization is a powerful way to constrain the optical depth to reionization and search for the signature of inflation through the detection of primordial B-modes. We present an analysis of maps covering 73.6% of the sky made from the 40 GHz channel of the Cosmology Large Angular Scale Surveyor (CLASS) from 2016 August to 2022 May. Taking advantage of the measurement stability enabled by front-end polarization modulation and excellent conditions from the Atacama Desert, we show this channel achieves higher sensitivity than the analogous frequencies from satellite measurements in the range 10 < ℓ < 100. Simulations show the CLASS linear (circular) polarization maps have a white noise level of 125(130)μKarcmin . We measure the Galaxy-masked EE and BB spectra of diffuse synchrotron radiation and compare to space-based measurements at similar frequencies. In combination with external data, we expand measurements of the spatial variations of the synchrotron spectral energy density (SED) to include new sky regions and measure the diffuse SED in the harmonic domain. We place a new upper limit on a background of circular polarization in the range 5 < ℓ < 125 with the first bin showing D ℓ < 0.023 μKCMB2 at 95% confidence. These results establish a new standard for recovery of the largest-scale CMB polarization from the ground and signal exciting possibilities when the higher sensitivity and higher-frequency CLASS channels are included in the analysis.

High accuracy synchrotron radiation interferometry with relativistic electrons

A high-precision hypernuclear experiment has been performed at the Mainz Microtron (MAMI) to determine the hypertriton Λ binding energy via decay-pion spectroscopy. A key element of this measurement is an accurate calibration of the magnetic spectrometers with the MAMI beam. For such an absolute calibration with small statistical and systematic uncertainties the undulator light interference method will be applied. In this contribution the basic principle of this method is discussed and the analysis status of the measured synchrotron radiation spectra is presented.

3R-IrO2 Two-Dimensional Nanosheets with Varying Layer Spacing and [IrO6] Distortion for OER

Here, two iridium-based crystal structures, K0.3IrO2·xH2O and Rb0.3IrO2·xH2O, have been synthesized for application in the oxygen evolution reaction (OER). The 3R-type layered IrO2 structures with different lattice parameters were successfully obtained from the two Ir structures by the hydrogen ion exchange method. According to synchrotron radiation spectra and the theoretical calculation of density functional theory (DFT), the increase of oxygen vacancy concentration caused by lattice distortion in the 3R-IrO2 crystal is negatively correlated with the activity of OER. A high concentration of oxygen vacancies will reduce Ir–O hybridization, which is not conducive to the balance between the adsorption and desorption of intermediate products. The higher OH adsorption energy barrier and band gap of the 3R-IrO2 crystal limited the improvement of electrochemical performance. In addition, through the analysis of the bonding orbitals and antibonding orbitals of the two structures, we concluded that 3R-IrO2 belongs to the nonthermodynamically stable structure and is not suitable for hydrogen production by electrolysis of water.

A Spear and Shield-Inspired Ar Plasma Safeguard Few-Layer Black Phosphore with Firefighting of Epoxy Resin.

Appearing as an innovative and efficient strategy, a facile strategy of a plasma ball mill is carried out to prepare few-layer black phosphorus nanosheets (BPNSs), for abating the fire risk of epoxy resin (EP). A spear and shield-inspired Ar plasma emergeed through a plasma ball mill to prevent Ar@BP nanosheets from oxidation compared with the preparation of BP nanosheets (MBPNSs) in a mechanical ball mill. The absorption coefficient in the synchrotron radiation spectrum is increased by 16.91%, indicating that BP is effectively protected by Ar proof. The Vienna ab initio simulation reveals that the combination of Ar@BP with oxygen cannot proceed spontaneously with the binding energy of 4.44eV. With the introduction of 1.5 wt% Ar@BP, the total heat release (THR), total smoke release (TSR), total smoke production(TSP), CO, and CO2 yield, compared with that of EP, are descended by 30.40%, 24.41%, 24.10%, 33.23%, and 37.60%, respectively, indicating excellent flame retardancy property. It is attributed to the condensed and gas phase function. Meanwhile, the tensile strength and elongation at break increase by 27.92% and 56.04%, respectively, with the incorporation of 1.5 wt% Ar@BP.

High Field Hybrid Permanent Magnet Wiggler Optimized for Tunable Synchrotron Radiation Spectrum

Synchrotron radiation provides a powerful tool of high brightness and tunable energy range for scientific applications in different domains such as chemistry, biology, material science and many others. The scientific community has recently shown a great interest in high-energy photons for other applications such as archaeological studies. To meet different demands, this study gives two proposals: called proposal 1: wiggler of 164 mm period and proposal 2: wiggler 98 mm period. Each proposal provides a single insertion device that can operate in the wiggler regime at high-energy range and in the undulator regime at low-energy range by simple gap adjustment. It develops the concept of insertion devices, gives a detailed study of the possible technologies, provides a simulation of the emitted photon flux by the proposed insertions, and compares the emitted radiation of each of them. It is found that proposal 1 provides 10^5 more flux in the undulator regime and 10 times more flux in the wiggler regime

The FCC-ee vacuum system, from conceptual to prototyping

The FCC-ee is a very challenging accelerator project from the point of view of vacuum. Apart from the sheer size of the machine, a twin-ring of 100 km circumference, the vacuum system design must be capable of dealing with the low-energy 45.6 GeV, high-current version of the machine (the Z-pole) as well as the higher energy, lower current versions. The main difficulty is related to the very much different synchrotron radiation (SR) spectra of the Z-pole vs the other energies, in particular the ttbar at 182.5 GeV. The critical energy of the SR spectrum of the Z-pole is 19.5 keV, while the ttbar exceeds 1.2 MeV. It is particularly challenging in terms of shielding the beryllium chamber in the detectors, for the Machine Detector Interface (MDI) area. We discuss the evolution of the vacuum system design for the arc sections, and some new ideas on NEG-coating, SR absorbers, and pumping system, with the aim to build prototypes soon, in the framework of the FCC Innovation Study program. The design of the vacuum hardware depends on the choices made for the magnets, and the required shielding from high-energy radiation generated by the circulating beam interacting with the residual gas and the interaction of the intense SR fans with the photon. There is also an important collaboration with the engineering integration of the vacuum system in the tunnel, particularly considering the full-energy booster injector, which is not detailed here. We also briefly describe the raytracing montecarlo modelling efforts carried out in the MDI area, and its pumping configuration.

Very high-resolution Synchrotron radiation far infrared spectrum of C-13 methanol arising from the ground torsional vibrational state and evidence of avoided crossing due to ΔK = 4 interaction

In this work, very high-resolution far-infrared (FIR) and infrared (IR) Synchrotron Radiation spectra of C-13 substituted methanol species have been recorded with very high signal-to-noise (S/N) ratio in the entire region from 40 to 5000 cm−1. High resolution allowed the recording to be done with an unprecedented resolution of about 0.0014 cm−1 which is on the order of the doppler width of the lines. The peak of the spectral lines could be obtained with an estimated accuracy of ± 5 KHz. Analysis of the spectra has been performed for quantum numbers associated with the torsional ground state. Assignments have been obtained for K- values up to about 15 and J- values of about 35 for the three symmetry species. Asymmetry splitting has been observed for low K transitions and accurate asymmetry splitting constants have been obtained. Including the available microwave (MW) and millimeter-wave (MMW) measurements, a complete set of spectral line assignments have been obtained for the ground torsional state of the vibrational state. Following J.K. Watson’s method [1] all the spectral lines have been fitted to the exact term values of the energy levels. Localized perturbation has been observed for K = 9 A and state mixing resulted in forbidden transitions through intensity borrowing. A complete atlas has been presented for all possible quantum numbers for the ground state levels and the accurate term values have been obtained for all possible states. According to our knowledge, this atlas represents the most accurate line positions for this species reported so far. In addition, the results have been applied to confirm and obtain very accurate wavenumbers for several FIR laser lines pumped by CO2 lasers. The present atlas may be useful as a secondary wavenumber standard in the FIR region and should be useful for astrophysical detection.

STOCHASTIC MECHANISM OF BROADENING SPECTRAL DENSITY OF SYNCHROTRON RADIATION OF RELATIVISTIC ELECTRON

The consideration is based on the study of the spectral profile of the synchrotron radiation (SR) line of a relativistic electron orbiting in a circular orbit in the uniform magnetic field. Fast stochastic fluctuations accompanying the motion of the electron during emission of SR quanta lead to the formation of spectral contour of each SR harmonic and it’s broadening. It is shown that the joint broadening of the set of harmonics causes broadening of the SR spectrum as the whole. The results of numerical calculations on the formation of the final SR spectral density of a relativistic electron are presented. In order to obtain precision characteristics, the formation of SR density in the frequency range exceeding the critical frequency has been studied.

Principles and applications of a comprehensive characterization method combining synchrotron radiation technology, transmission electron microscopy, and density functional theory

<p indent="0mm">Synchrotron radiation and transmission electron microscopy (TEM) technologies are important characterization methods of materials and are widely used in the frontier research fields of physics, chemistry, materials, environment, and energy. Both methods exploit the interaction of photons and electrons with materials, including the scattering and absorption of photons in the material and the diffraction and energy loss of electrons. Through these techniques, various specific characterization methods have evolved. In the density functional theory (DFT) which is based on quantum mechanics, the eigenfunction can be related to the charge density obtained from the synchrotron radiation X-rays diffraction and electron diffraction in TEMs, and the eigenvalue corresponds to the energy level or band structure obtained from the photoelectron emission spectra/absorption spectra of synchrotron radiation and the electron energy loss spectra of TEM. With these corresponding relations, the two techniques and theoretical calculations can verify and/or complement each other, providing detailed analyses of the structure and electronic information of materials. This article reviews the progress of synchrotron radiation and transmission electron microscopy technologies and their applications to typical material characterization. The article emphasizes how the spatial and temporal resolutions of both technologies have advanced through nanotechnology and quantum mechanics developments. Such cutting-edge technology will promote the discovery of new functional materials.

Systematic Study of Acceleration Efficiency in Young Supernova Remnants with Nonthermal X-Ray Observations

Abstract Cutoff energy in a synchrotron radiation spectrum of a supernova remnant (SNR) contains a key parameter of ongoing particle acceleration. We systematically analyze 11 young SNRs, including all historical SNRs, to measure the cutoff energy, thus shedding light on the nature of particle acceleration at the early stage of SNR evolution. The nonthermal (synchrotron) dominated spectra in filament-like outer rims are selectively extracted and used for spectral fitting because our model assumes that accelerated electrons are concentrated in the vicinity of the shock front owing to synchrotron cooling. The cutoff energy parameter (ε 0) and shock speed (v sh) are related as ε 0 ∝ v sh 2 η − 1 with a Bohm factor of η. Five SNRs provide us with spatially resolved ε 0–v sh plots across the remnants, indicating a variety of particle acceleration. With all SNRs considered together, the systematic tendency of η clarifies a correlation between η and an age of t (or an expansion parameter of m) as η ∝ t −0.4 (η ∝ m 4). This might be interpreted as the magnetic field becomes more turbulent and self-generated, as particles are accelerated at a greater rate with time. The maximum energy achieved in SNRs can be higher if we consider the newly observed time dependence on η.

Electron injection induced phase transition of 2H to 1T MoS2 by cobalt and nickel substitutional doping

The semiconducting to metallic phase transition mechanism of MoS2 has gained immense attention due to the excellent electrocatalytic activity seen in catalysts and energy storage devices. However, the harsh conditions required for effective phase transition limits the applications of these materials. Compared with using flammable reductants, obtain metallic phase MoS2 by a chimie-douce route is widely expected. Herein, we synthesized high-1T phase-ratio MoS2 through a mild hydrothermal method with assistance of cobalt and nickel. The microstructure and composition of the Co,Ni-MoS2 material were detailed explored by cs-corrector transmission electron microscopy and synchrotron radiation spectrum. The process of phase transition was simulated by density functional theory calculation. We found that the phase transition was induced by electron injection during cobalt and nickel co-doping. Owing to abundant 1T-phase and smaller hydrogen adsorption/desorption energy, the prepared Co,Ni-MoS2 shows excellent hydrogen evolution reaction performance in alkaline solution.

A novel experimental method in connecting the trans- and gauche-states of Ethanol to high accuracy using synchrotron radiation spectrum through torsionally excited state transitions

In this report the initial results of a breakthrough and novel method to energetically connect the lowest-lying trans- (e0) and the gauche- (e1 and o1) states of Ethyl Alcohol. It is well known that the transitions between the trans- and gauche states in the ground internal rotational levels for OH torsion are forbidden due to symmetry considerations. This presented a considerable challenge to model the Hamiltonian for this molecule on a global basis and the most successful model required these two states to be treated separately as if the trans- and gauche- states represent two different molecules. The present communication reports for the very first time the method to energetically connect the trans- sub-states and the gauche sub-states with experimental accuracy. This would open a new vista to theoretical spectroscopists for a global model with both types of symmetry. The novel method has been conceived recently with the availability of high-resolution far-infrared (FIR) with very little noise. The spectroscopic idea behind the approach is presented here using a few representative states in the form of a rapid publication. The details are in progress and will be commutated in a future report.

Spectral Signatures of PeVatrons

Abstract We analyze the energy distributions of final (stable) products—gamma rays, neutrinos, and electrons—produced in inelastic proton–proton collisions in the PeV energy regime. We also calculate the energy spectrum of synchrotron radiation from secondary electrons, assuming that these are promptly cooled in the surrounding magnetic field. We show that the synchrotron radiation has an energy distribution much shallower than that of primary protons, hence we suggest taking advantage of such a feature in the spectral analysis of the highest-energy (cutoff) emission region from particle accelerators. For a broad range of energy distributions in the parent protons, we propose simple analytical presentations for the spectra of secondaries in the cutoff region. These results can be used in the interpretation of high-energy radiation from PeVatrons—cosmic-ray factories accelerating protons to energies up to 1 PeV.

Electron beam and betatron x-ray generation in a hybrid electron accelerator driven by high intensity picosecond laser pulses

We experimentally studied electron beams and synchrotron x-ray radiation generated from the interaction of high-intensity picosecond laser pulses of 1–3 × 1019 W/cm2 with underdense plasmas of 1–8 × 1019 cm−3. Electron beams with maximum energy over 120 MeV, hundreds mrad divergence and tens of nC charge were generated in the experiments. The measured x-ray spectra were fit well with a synchrotron radiation spectrum combination with a bremsstrahlung spectrum. When laser pulses with intensity of 2.38 × 1019 W/cm2 interacting with pure Nitrogen gas with density of 2.35 × 1018 cm−3, we obtained betatron x-ray radiation with critical energy 3–4 keV and photon number up to 1013 photons/Sr per shot, the energy conversion efficiency is about 3 × 10−5. The high photon yield and large energy conversion efficiency are due to large amounts of electrons trapped by self-modulated laser wakefield and mainly accelerated by direct-laser-acceleration mechanism. Such high yield betatron x-ray sources have widely application prospect as backlight or probe in large scale of laser facilities used for high energy density or fusion sciences.

Gamma-Ray Burst Spectrum with a Time-dependent Injection Rate of High-energy Electrons

Abstract Although the physical origin of prompt emission in gamma-ray bursts (GRBs) remains inconclusive, previous studies have considered the synchrotron radiation of relativistic electrons as a promising mechanism. These works usually adopted an invariable injection rate of electrons (Q) which may be discordant with that in a Poynting-flux-dominated jet. In a Poynting-flux-dominated jet (e.g., internal-collision-induced magnetic reconnection and turbulence model), the number of magnetic reconnections occurring simultaneously may grow rapidly with time and result in an increase of Q with time. This paper is dedicated to studying the synchrotron radiation spectrum in this scenario. It is found that the radiation spectrum would obviously get harder if an increasing Q is adopted and a Band-like radiation spectrum can be obtained if the increase of Q is fast enough. The latter is related to the fact that a bump shape rather than a power-law spectrum appears in the low-energy regime of the obtained electron spectrum. This effect can strongly harden the low-energy radiation spectrum. It indicates that an increasing Q can help to alleviate the “fast-cooling problem” of synchrotron radiation for GRBs. Our studies also reveal that a Poynting-flux dominated jet with a large emission radius, a short magnetic reconnection region length, or an injected electron with low minimum energy would prefer to form a Band-like radiation spectrum. We suggest that the Band spectrum found in GRBs may be the synchrotron emission of the electrons with a bump-shape distribution in its low-energy regime.

Review of Transverse Beam Profile Measurements Using Synchrotron Radiation

Abstract –Synchrotron radiation (SR) is a tool for non-destructive beam diagnostics since its characters are substantially related to those of the source beam. The spectrum of SR is extremely intense and extends over a broad energy range from the infrared through the visible and ultraviolet, into the soft and hard X-ray regions of the electromagnetic spectrum. The visible light (400 – 800 nm) and X-ray (0.05 – 0.3 nm) regions are used in the beam instrumentation. In the visible light region, transverse beam profile or size diagnostics can be done by an interferometer (light is observed as a wave). Meanwhile, in the submicron beam size measurements, the X-ray SR monitor is commonly used. This paper reports the review of transverse beam profile measurements using SR covering principles and practical experiences with the technique at some accelerator facilities such as Photon Factory, Diamond Light Source, CesrTA, and SuperKEKB. Key words: accelerator, beam instrumentation, transverse beam profile, synchrotron radiation, X-ray, visible light

Exact Analytical Expression for the Synchrotron Radiation Spectrum in the Gaussian Turbulent Magnetic Field

Abstract We demonstrate that the exact solution for the spectrum of synchrotron radiation from an isotropic population of monoenergetic electrons in a turbulent magnetic field with a Gaussian distribution of local field strengths can be expressed in the simple analytic form: , where We use this expression to find the approximate synchrotron spectra for power-law electron distributions with -type high-energy cutoff; the resulting synchrotron spectrum has the exponential cutoff factor with a frequency raised to the 2β/(3β + 4) power in the exponent. For the power-law electron distribution without a high-energy cutoff, we find the coefficient a m as a function of the power-law index, which results in the exact expression for the synchrotron spectrum when using the monochromatic (i.e., each electron radiates at the frequency ) approximation.

Commissioning of a beam screen test bench experiment with a future circular hadron collider type synchrotron radiation beam

Coping with synchrotron radiation (SR) that originated at superconducting bending magnets is one of the major challenges in the design of the vacuum beam pipes of hadron colliders. In the case of the Future Circular hadron Collider (FCC-hh), similarly as for the LHC, a beam screen, operating at higher temperatures than the cold mass, has been designed in order to preserve the superconducting magnet cold bores from direct synchrotron irradiation. The quality of the beam screen vacuum can be severely compromised by the absorption of SR into its walls, enhancing the risk for numerous beam detrimental effects to arise. In order to experimentally study such effects and develop strategies for their minimization, a beam screen test bench experiment (BESTEX) has been conceived and installed in the Karlsruhe Research Accelerator storage ring at the Karlsruhe Institute for Technology. The BESTEX has been designed to explore photon stimulated desorption, photon reflectivity, photon heat loads, and photoelectron generation originated on beam screen prototypes under irradiation of the FCC-hh-like SR spectrum. A detailed description of the BESTEX, its commissioning, and its functionality is hereby presented.