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Design, development and use of the spectrometer for investigating coherent THz radiation produced by micro-bunching instabilities at Diamond Light Source
摘要： Schottky barrier diodes (SBDs) are known for their low noise, ultra-fast response and excellent sensitivity. They are often implemented as detectors in the millimetre wavelength regime. Micro-bunch instabilities (MBI) have been detected at many light sources around the world including the Diamond Light Source, UK. These MBI can result in bursts of coherent synchrotron radiation (CSR) with millimetre wavelengths. More research needs to be carried out with regards to the dynamics of MBI in order to con?rm the simulations and to eventually harness the power of the CSR bursts. A single shot spectrometer has been designed and is under operation at the Diamond Light Source (DLS). It is composed of eight SBDs ranging from 33-1000 GHz. Unlike previous measurements carried out, each of the SBDs has been individually characterised thus making the results obtained comparable to simulations. In this paper, we present the assessment of each SBD in the spectrometer and the ?rst results of the spectrometer’s use in the beam.
关键词： Schottky barrier diodes,micro-bunch instabilities,spectrometer,coherent synchrotron radiation,Diamond Light Source
更新于2025-09-09 09:28:46
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Reference Module in Materials Science and Materials Engineering || Compton Scattering
摘要： Compton effect which was invented by Arthur Holly Compton (Compton, 1923a,b) was a milestone in the development of quantum mechanics. In 1929, DuMond and collaborators (DuMond, 1929) firstly explained the shape of Compton profile of beryllium within the Fermi–Dirac statistics. After that a couple of basic studies on Compton profiles and the electron momentum densities were performed in the 1930s (DuMond and Kirkpatrick, 1930). With the development of new generation of photon detectors, this technique was re-established in the mid-1960s. Several reviews on development of this technique are available in literature (Williams, 1977; Cooper, 1985; Lovesey and Collins, 1995; Cooper et al., 2004; Schülke, 2007; Ahuja, 2010). With the advent of third generation synchrotron radiation (SR) sources along with the further improvement in the detector technology, Compton scattering (CS) is now established as a well recognized tool to study electronic properties of variety of materials. Even CS is being employed to study the magnetic behavior of materials using circularly polarized SRs.
关键词： electronic properties,Compton Scattering,synchrotron radiation,magnetic behavior
更新于2025-09-04 15:30:14
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Cr/C Reflective Multilayer for Wavelength of 44.8 ?
摘要： The working wavelength of Ni-like, Ta soft X-ray laser is 44.8 ?, just near the “water window.” High re?ection multilayers are required for this kind of laser in China. In this work, we design and fabricate carbon-based multilayer re?ective samples. The Cr/C multilayer was selected from proposed candidates such as Co/C, Ni/C, and CoCr/C material combinations. The period thickness is only 22.6 ?. Cr/C multilayers were deposited by the magnetron sputtering method. Multilayers with bi-layer numbers of 150, 200, 250 and 300 were deposited onto super polished silicon wafers. All multilayers have been characterized by grazing incidence X-ray re?ectance (GIXRR). Then, near-normal incidence re?ectance measurements were performed at beamline 3W1B, Beijing synchrotron radiation (BSRF). The highest re?ectance of 13.2% is achieved with the bi-layer number of 300. Transmission electron microscopy measurements also clearly show the sharp Cr–C interfaces in the multilayer.
关键词： Multilayer,Soft X-ray Laser,Re?ectance,Magnetron Sputtering,Synchrotron Radiation
更新于2025-09-04 15:30:14
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Separation and Pre–Concentration of Metal Cations – DNA/RNA Chelates Using Molecular Beam Mass Spectrometry with Tunable Vacuum Ultraviolet (VUV) Synchrotron Radiation and Various Analytical Methods
摘要： Separation and pre–concentration procedures such as Liquid–Liquid Extraction (LLE), Solid Phase Extraction (SPE) and Homogenous Liquid–Liquid Extraction (HLLE) make it feasible to determine the trace of metal cations such as Mg2+, Ca2+, Cr3+, Mn2+, Fe3+, Co2+, Co3+, Ni2+, Cu2+, Zn2+, Se2+, Mo6+, Ru4+, Rh3+, Pd2+, Ag+, Cd2+, Sn2+, Te2+, Te4+, Hg2+ and Pb2+ in natural samples using molecular beam mass spectrometry with tunable Vacuum Ultraviolet (VUV) synchrotron radiation (Figure 1) and various analytical methods [1-21]. Pre–concentration methods generally improve sensitivity and selectivity of the analysis with the additional advantage of isolation the analyte from the interfering compounds [22,23]. In the recent years, Homogenous Liquid– Liquid Extraction (HLLE) using molecular beam mass spectrometry with tunable Vacuum Ultraviolet (VUV) synchrotron radiation and various analytical methods has been extensively used in sample preparation due to speed, suitable performance, higher concentration factor and less solvent consumption in comparison with Liquid–Liquid Extraction (LLE) and Solid Phase Extraction (SPE) [24-44]. In the present editorial, an effective method is presented for pre–concentration of Mg2+, Ca2+, Cr3+, Mn2+, Fe3+, Co2+, Co3+, Ni2+, Cu2+, Zn2+, Se2+, Mo6+, Ru4+, Rh3+, Pd2+, Ag+, Cd2+, Sn2+, Te2+, Te4+, Hg2+ and Pb2+ by Homogenous Liquid–Liquid Extraction (HLLE) and using molecular beam mass spectrometry with tunable Vacuum Ultraviolet (VUV) Synchrotron radiation and various analytical methods.
关键词： Separation,Pre–Concentration,Vacuum Ultraviolet (VUV) Synchrotron Radiation,Molecular Beam Mass Spectrometry,DNA/RNA Chelates,Metal Cations,Analytical Methods
更新于2025-09-04 15:30:14
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Infrared microscopy in the study of cellular biochemistry
摘要： This is a personal overview of the background, motivation and objectives in the application of infrared spectromicroscopy techniques to the study of cellular biochemistry, as detailed in a presentation given at WIRMS2017. It was not the aim of the presentation, nor is it the aim of the present article, to be a systematic review of the field of biological IR microscopy. Rather, it highlights the motivation for the author to use IR microscopy in biological research, with an emphasis on experiments that address specific questions in biochemical and cellular research. It also comments on the role of conventional light sources and synchrotron radiation in these experiments and justifies the use of synchrotron light in their implementation. The synchrotron advantage for experiments on live cells is reassessed in view of recent developments in the technology of IR light sources, in particular the introduction of novel designs of mid-infrared lasers. Finally, future applications of synchrotron IR light to the field are discussed with respect to the introduction of near-field techniques for IR imaging and spectroscopy of cellular samples, such as sSNOM and AFM-IR.
关键词： Metabolism,Infrared microscopy,Tomography,Synchrotron radiation,Live cells
更新于2025-09-04 15:30:14
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Detection of high flux synchrotron radiation based on diamond detector for HEPS
摘要： High Energy Photon Source (HEPS) with a beam energy of 6 GeV and emittance less than 1.0 nm rad will be constructed in China, which can provide high-brightness hard X-ray in the order of 1022 (phs/s/mm2/mr2/0.1%B.W.). The broadband and high-brightness monochromatic beam flux and white beam flux need new detector other than the ion chambers for measurement in case of saturation under high-flux conditions. The Diamond X-ray detector for the beam position monitoring and high brightness X-ray detection is developing for High Energy Photon Source in China. The diamond detector has advantages over other detector materials: a low atomic number resulting in a low absorption cross-section when used as beam position monitor and a high radiation and wide linear range when used as beam intensity measuring. In this paper, the polycrystalline chemical-vapour-deposition diamond detectors with an aluminium contact have been tested at 1W2B beamline at Beijing Synchrotron Radiation Facility (BSRF). A transmission-mode diamond X-ray detector is designed to simultaneously measure the X-ray flux, beam position in real time.
关键词： HEPS,High brightness synchrotron radiation,Beam position,Diamond detector
更新于2025-09-04 15:30:14
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Characterisation of sensor kinase by CD spectroscopy: golden rules and tips
摘要： This is a review that describes the golden rules and tips on how to characterise the molecular interactions of membrane sensor kinase proteins with ligands using mainly circular dichroism (CD) spectroscopy. CD spectroscopy is essential for this task as any conformational change observed in the far-UV (secondary structures (α-helix, β-strands, poly-proline of type II, β-turns, irregular and folding) and near-UV regions [local environment of the aromatic side-chains of amino acid residues (Phe, Tyr and Trp) and ligands (drugs) and prosthetic groups ( porphyrins, cofactors and coenzymes (FMN, FAD, NAD))] upon ligand addition to the protein can be used to determine qualitatively and quantitatively ligand-binding interactions. Advantages of using CD versus other techniques will be discussed. The difference CD spectra of the protein–ligand mixtures calculated subtracting the spectra of the ligand at various molar ratios can be used to determine the type of conformational changes induced by the ligand in terms of the estimated content of the various elements of protein secondary structure. The highly collimated microbeam and high photon flux of Diamond Light Source B23 beamline for synchrotron radiation circular dichroism (SRCD) enable the use of minimal amount of membrane proteins (7.5 mg for a 0.5 mg/ml solution) for high-throughput screening. Several examples of CD titrations of membrane proteins with a variety of ligands are described herein including the protocol tips that would guide the choice of the appropriate parameters to conduct these titrations by CD/SRCD in the best possible way.
关键词： high-throughput screening,circular dichroism,synchrotron radiation circular dichroism,membrane sensor kinase,ligand-binding interactions
更新于2025-09-04 15:30:14