Existing copper-coated carbon fibers used in wire scanners to measure the transverse beam profile in the accelerators at CERN are approaching material limits. A new instrument design has showed that ...the main limitation now comes from the centerpiece of the instrument: the wire. Large amplitude vibrations increase the risk of failure during scans. New required specifications concerning the beam measurements for the Future Circular Collider (FCC) project cannot be met. Fortunately, the commercial development of long microscopic yarns made of spun carbon nanotubes has paved the way for possible alternatives. The objective of this study is to determine if those Carbon NanoTube Yarns (CNTY) could replace the current carbon fibers (CF) for beam instrumentation, and if so, to determine the best configuration in terms of diameters and mounting system. To do so, we have made extensive testing and microscopy on CNT yarns with diameters of 10, 20 and 30 μm, with two different mounting systems, the Paper Frame conditioning (PF) or partial Copper-Coated conditioning (CC). A Weibull approach was used to extrapolate our results to the real length of the wires used in operational instruments. This study shows that considering the Weibull criteria, the best configuration to increase the accuracy of the beam profile measurement is to use a not copper-coated 20 μm diameter CNTY.
The LHC Injectors Upgrade (LIU) program included new fast beam wire scanners (BWS) to meet the requirements of the higher brightness and intensity High Luminosity LHC (HL-LHC) beams. Seventeen LIU ...BWS have been installed during the LHC second long shutdown (LS2) and they are currently used in the daily operations of the LHC injectors. After giving an overview of the LIU project and the general beam instrumentation upgrades associated with it, this paper presents a short review of the mechanical design and layout of the LIU BWS, the electronics involved, and then focuses on the first results obtained during their commissioning.
•Development of two non-invasive beam profile monitors.•Key features of both profile monitors.•Experimental results for the beam profile measurements using helium, nitrogen and neon gases.•Density ...measurements for the gas jet.•Ongoing development of Quantum gas jet system and for optimization of gas jet density.
A beam profile monitor based on a supersonic gas-curtain is currently under development for transverse profile diagnostics of electron and proton beams in the High Luminosity LHC. This monitor uses a thin supersonic gas curtain that crosses the primary beam to be characterized under an angle of 45 degrees. The fluorescence caused by the interaction between the beam and gas-curtain is detected using a specially designed imaging system to determine the 2D transverse profile of the primary beam. Another prototype monitor based on beam induced ionization is installed at The Cockcroft Institute. This paper presents the design features of both the monitors, the gas-jet curtain formation and various experimental tests, including profile measurements of an electron beam, using helium, nitrogen and neon as gases. Such a non-invasive online beam profile monitor would be highly desirable also for medical LINAC’s and storage rings as it can characterize the beam without stopping machine operation. The paper discusses opportunities for simplifying the monitor design for integration into a medical accelerator and expected monitor performance.
Fifty‐one essential oils extracted from plants of known origin were tested for their antimicrobial activity against three bacteria, Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and ...four yeasts, Torulopsis utilis, Schizosaccharomyces pombe, Candida albicans and Saccharomyces cerevisiae using the drop diffusion method. All showed antimicrobial activity against at least one of the micro‐organisms. Following this preliminary screening, 13 essential oils showing antimicrobial activity against at least five of the micro‐organisms were tested in the range 50 μg ml−1 to 500 μg ml−1 using broth micro dilution techniques with dimethylsulphoxide (DMSO) as a dispersing solvent. The concentration of most of the oils required for total inhibition of growth was >500 μg ml−1. Further studies on the antimicrobial action of cinnamon oil in the range 10–150 μg ml−1 showed that 50‐fold higher activity was found when no dispersing solvent was used.
The beam-gas vertex (BGV) detector is an innovative instrument measuring noninvasively the transverse beam size in the Large Hadron Collider (LHC) using reconstructed tracks from beam-gas ...interactions. The BGV detector was installed in 2016 as part of the R&D for the High-Luminosity LHC project. It allows beam size measurements throughout the LHC acceleration cycle with high-intensity physics beams. A precision better than 2% with an integration time of less than 30 s is obtained on the average beam size measured, while the transverse size of individual proton bunches is measured with a resolution of 5% within 5 min. Particles emerging from beam-gas interactions in a specially developed gas volume along the beam direction are recorded by two tracking stations made of scintillating fibers. A scintillator trigger system selects, on-line, events with tracks originating from the interaction region. All the detector elements are located outside the beam vacuum pipe to simplify the design and minimize interference with the accelerated particle beam. The beam size measurement results presented here are based on the correlation between tracks originating from the same beam-gas interaction vertex.
The essential oil extracted from palmarosa (
Cymbopogon martinii) has proven anti-microbial properties against cells of
Saccharomyces cerevisiae. Low concentrations of the oil (0.1%) inhibited the ...growth of
S. cerevisiae cells completely. The composition of the sample of palmarosa oil was determined as 65% geraniol and 20% geranyl acetate as confirmed by GC–FTIR. The effect of palmarosa oil in causing K
+ leakage from yeast cells was attributed mainly to geraniol. Some leakage of magnesium ions was also observed. Blocking potassium membrane channels with caesium ions before addition of palmarosa oil did not change the extent of K
+ ion leakage, which was equal to the total sequestered K
+ in the cells. Palmarosa oil led to changes in the composition of the yeast cell membrane, with more saturated and less unsaturated fatty acids in the membrane after exposure of
S. cerevisiae cells to the oil. Some of the palmarosa oil was lost by volatilization during incubation of the oil with the yeast cells. The actual concentration of the oil components affecting the yeast cells could not therefore be accurately determined.
Geraniol in palmarosa oil led to changes in composition of the yeast cell membrane, with leakage of K
+ and Mg
2+ ions from cells.
Electron microscopic and biochemical studies of lignocellulose degradation by wood-rotting fungi have shown that enzymes such as lignin peroxidases, manganese dependent peroxidases, laccases and ...cellulases are too large to penetrate undegraded secondary wood cell walls. Degradation occurs by surface interaction between cell wall and enzymes, but initiation of decay at a distance from the fungal hyphae must involve diffusible low-molecular mass agents. The roles of hydrogen peroxide, veratryl alcohol, oxalate, Fe2(+)-Fe3(+) and Mn2(+)-Mn3(+), as such agents in lignocellulose degradation are discussed.
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