Pulsed Ion Research Articles

Pulsed Nano-Electrospray Ionization Applied to Solutions of Angiotensin II, Bradykinin, and Gramicidin S in Water/Acetonitrile (1/1) with the Addition of 1% Acetic Acid and 10 mM Ammonium Acetate

Pulsed Nano-Electrospray Ionization Applied to Solutions of Angiotensin II, Bradykinin, and Gramicidin S in Water/Acetonitrile (1/1) with the Addition of 1% Acetic Acid and 10 mM Ammonium Acetate

Deposition of thin refractory-metal-films onto glasses through diaphragms at plasma focus facility

The results of experiments are presented on the deposition onto silicate glasses of thin refractorymetal- films: molybdenum, tantalum and tungsten. The technique used for manufacturing films was based on the deposition of metal-containing plasma formed when exposing the surface of foils made of refractory metals to high-power plasma and ion pulses. For generation of such pulses, the facility of plasma focus type was used, which makes it possible to obtain ion beams and plasma flows with the energy flux density in the range of 1010—1012 W/cm2. The most intense central part of the ion-plasma flow was separated using metal diaphragms with aperture diameters of 2.5, 3.5, and 4.5 mm. Metal Mo, Ta and W films with dimensions of ∅ 3—5 mm were obtained on the surfaces of glasses. Metal films are characterized by good adhesion, since they coalesce with the glass surface. It was discovered that the planarity of films becomes violated due to the drift of molten metal particles under the glass surface. The relief of films is non-uniform, which can be explained by the presence of micrometer-sized metal particles in the plasma flow.

Detection of Veterinary Drugs in Food Using a Portable Mass Spectrometer Coupled with Solid-Phase Microextraction Arrow.

A portable mass spectrometer (PMS) was combined with a mesoporous silica material (SBA-15) coated solid-phase microextraction (SPME) Arrow to develop a rapid, easy-to-operate and sensitive method for detecting five veterinary drugs-amantadine, thiabendazole, sulfamethazine, clenbuterol, and ractopamine-in milk and chicken samples. Equipped with a pulsed direct current electrospray ionization source and a hyperboloid linear ion trap, the PMS can simultaneously detect all five analytes in approximately 30 s using a one-microliter sample. Unlike traditional large-scale instruments, this method shows great potential for on-site detection with no need for chromatographic pre-separation and minimal sample preparation. The SBA-15-SPME Arrow, fabricated via electrospinning, demonstrated superior extraction efficiency compared to commercially available SPME Arrows. Optimization of the coating preparation conditions and SPME procedures was conducted to enhance the extraction efficiency of the SBA-15-SPME Arrow. The extraction and desorption processes were optimized to require only 15 and 30 min, respectively. The SBA-15-SPME Arrow-PMS method showed high precision and sensitivity, with detection limits and quantitation limits of 2.8-9.3 µg kg-1 and 10-28 µg kg-1, respectively, in milk. The LOD and LOQ ranged from 3.5 to 11.7 µg kg-1 and 12 to 35 µg kg-1, respectively, in chicken. The method sensitivity meets the requirements of domestic and international regulations. This method was successfully applied to detect the five analytes in milk and chicken samples, with recoveries ranging from 85% to 116%. This approach represents a significant advancement in food safety by facilitating rapid, in-field monitoring of veterinary drug residues.

Synergy of high-intensity chromium ion implantation and ion beam energy impact on the zirconium alloy surface

The peculiarities and modes of material modification with high-intensity, high-power density ion beams on the irradiated surface are studied for the first time. Chromium ions are implanted into a zirconium alloy using a 25 kW/cm2, 450 μs beam at the pulse repetition rates within 8–35 pps. Every high-energy ion pulse impact is followed by ultrafast cooling of the surface due to heat removal into the target material. Three modes are studied at the temperatures of 580, 700, and 900 °C with an additional pulsed heating. An increase in the average target temperature from 580 to 700 °C within 1 h at the same pulse power density allows increasing the depth of chromium ion alloying from 1.5 to more than 7 μm. The use of ultrafast cooling of the Zr1%Nb alloy surface offers a grain size reduction from a few μm to approximately 50–250 nm, without any microstructural changes throughout the sample volume. An inhomogeneous chromium ion distribution over the target surface and depth is observed.

Generation of ultrashort ion pulses from ultrafast electron-stimulated desorption

We present an efficient method to produce laser-triggered proton pulses well below 500 ps pulse width at keV energies. We use femtosecond photoelectron pulses emitted from a cathode to enable ultrafast electron-stimulated desorption of adsorbates on a stainless steel plate under ultrahigh vacuum conditions. While direct photoionization of atoms to form well-timed ion pulses can suffer from a laser-focus-limited large starting volume, in our method the two-dimensional starting plane of the ions is defined with nanometer precision at a solid surface. We clearly outline how the method could be used in the future to efficiently produce ion beam pulses in the (sub)picosecond range for pump-probe experiments with ions. Published by the American Physical Society 2024

Comment on "Ultracold plasma expansion in quadrupole magnetic field".

Bronin etal. [Phys. Rev. E 108, 045209 (2023)2470-004510.1103/PhysRevE.108.045209] recently reported molecular-dynamics simulations of ultracold neutral plasmas expanding in a quadrupole magnetic field. While the main results are in agreement with prior experimental measurements, we present data showing oscillations not captured in the simulations of Bronin etal. Plasmas formed using pulsed or continuous-wave ionization processes have similar confinement times.

Deciphering the role of three-color synthesized laser pulse parameters in N2 ionization and attosecond pulse shaping

Photoionization of atoms or molecules is a fundamental process in strong-field physics, essential for generating high-order harmonics and producing attosecond pulses. Here, we investigate how a three-color laser field, consisting of wavelengths at 800 nm and its second and third harmonics, photoionizes N2 molecules and evaluates its effect on the properties of attosecond pulses. It has been discovered that by altering the relative phase, these harmonics periodically influence molecular ionization, increasing the discreteness and strength of the attosecond pulse trains. Three-color field driving dramatically raises the pulse peak while decreasing the width of the strongest peak pulse, whereas two-color field driving just slightly enhances the pulse intensity and duration. Furthermore, the effectiveness of harmonic production is significantly increased by varying the laser intensity ratios. Even though the efficiency and pulse intensity of the three-color field are limited by conversion efficiency, attosecond pulses with higher intensities can be produced with proper parameter tuning at lower ionization rates. These findings offer a significant foundation for precisely controlling attosecond pulse generation. Ocis codes320.7110; 320.7120.

Development of an Ion Mobility Spectrometer Based on a Pulsed Photoelectric Effect Ionization Source.

Ion mobility spectrometry (IMS) is a compact and sensitive trace gas analysis instrument that ionizes the sample into ions for detection. Typically, an ion gate is used to cut the continuous ion beam into ion packets for separation and detection. However, commonly used ion gates suffer from complex structures or low ion transmission rates, making the gateless IMS a viable alternative. In this study, an IMS based on a pulsed photoelectric effect ionization source was designed. The photoelectrons were generated by irradiating a photoelectric material with a back-illuminated pulsed xenon lamp. This allows for low-energy photoelectron generation and the production of simple reactant ions (O2-(H2O)n) and thus negative product ions. The photoelectron current generated by this ionization source was analyzed, which can reach an intensity of a few microamperes and can be converted into an ion signal exceeding 10 nA. The introduction of the pulsed photoelectric effect ionization source makes it possible to generate separate ion packets and complete ion injection when a constant electric field is maintained in the ionization region. And with an assisted pulsed electric field in the ionization region, the resolving power of the system can be effectively improved to 1.85 times that of the constant electric field. The IMS developed in this study was used for the detection of common volatile hazardous chemicals, yielding effective results. The detection limit for phenol was below 1 ppb, and the dynamic response range exceeded 1 order of magnitude, which implies the potential applications of this IMS to detect substances with high electron affinity, such as explosives detection in public safety.

Guided Mode Evolution and Ionization Injection in Meter-Scale Multi-GeV Laser Wakefield Accelerators.

We show that multi-GeV laser wakefield electron accelerators in meter-scale, low density hydrodynamic plasma waveguides operate in a new nonlinear propagation regime dominated by sustained beating of lowest order modes of the ponderomotively modified channel; this occurs whether or not the injected pulse is linearly matched to the guide. For a continuously doped gas jet, this emergent mode beating effect leads to axially modulated enhancement of ionization injection and a multi-GeV energy spectrum of multiple quasimonoenergetic peaks; the same process in a locally doped jet produces single multi-GeV peaks with <10% energy spread. A three-stage model of drive laser pulse evolution and ionization injection characterizes the beating effect and explains our experimental results.

Realizing laser-driven deuteron acceleration with low energy spread via in situ D2O-deposited target

Generation of quasi-monoenergetic ion pulse by laser-driven acceleration is one of the hot topics in laser plasma physics. In this study, we present a new method for the in situ deposition of an ultra-thin D2O layer on the surface of an aluminum foil target utilizing a spherical D2O capsule. Employing a 1019 W/cm2 laser, we achieve the acceleration of 10.8 MeV deuterons with an energy spread of ΔE/E = 4.6% in the most favorable shot. The energy spread depends on the exposure time of the D2O capsule in the vacuum chamber. This method has the potential to extend its applicability to other ion species.

Temperature and structure measurements of heavy-ion-heated diamond using in situ X-ray diagnostics

We present in situ measurements of spectrally resolved X-ray scattering and X-ray diffraction from monocrystalline diamond samples heated with an intense pulse of heavy ions. In this way, we determine the samples’ heating dynamics and their microscopic and macroscopic structural integrity over a timespan of several microseconds. Connecting the ratio of elastic to inelastic scattering with state-of-the-art density functional theory molecular dynamics simulations allows the inference of average temperatures around 1300 K, in agreement with predictions from stopping power calculations. The simultaneous diffraction measurements show no hints of any volumetric graphitization of the material, but do indicate the onset of fracture in the diamond sample. Our experiments pave the way for future studies at the Facility for Antiproton and Ion Research, where a substantially increased intensity of the heavy ion beam will be available.

Research on the minimum detection limit for measuring high-purity gases by gas chromatography

Abstract At present, the application fields of high-purity gases (purity reached 99.999% and above) include the semiconductor manufacturing industry, chemical analysis, fuel cells, aerospace, medicine, etc., and the quality and purity requirements of high-purity gases are also getting higher and higher. As the only detector that can detect ppb-level trace impurities, the pulsed discharge helium ionization detector (PDHID) is the most used detector in the field of high-purity gases. The minimum detection limit of existing PDHID-related analysis methods is usually calculated theoretically. In order to verify the actual minimum detection limit of PDHID, a multi-group gas distribution system was used in this paper to dilute the permanent gas components in the high-purity gas, and the gas chromatograph with pulsed discharge helium ionization detector (GC-PDHID) was used to detect the obtained different concentrations of standard gases. The experimental results showed that PDHID possessed high sensitivity, good linearity, and a wide linear range. The actual minimum detection limit for the permanent gas components in the high-purity gas could reach the ng/g (ppb) level, which could realize the detection of ultra-low concentration samples, and further verify the actual minimum detection limit of PDHID. This experiment provides a reference basis for the analysis of trace gases in the gas industry, especially in industries such as high-purity and ultra-high-purity gases and gas for the electronics industry, and is of great significance in actual production work.

Development of an online hydrogen fuel quality analyzer with gas chromatography-pulsed discharge helium ionization detector for applying hydrogen infrastructures.

Hydrogen fuel, which is essential for the hydrogen economy, including hydrogen cell vehicles, must be of high quality for optimal hydrogen cell use. Currently, hydrogen fuel quality control is mainly done by offline analysis with periodic sampling. However, with the anticipated surge in hydrogen charging stations, there's a pressing need for cost-effective, high-throughput online analysis systems. Additionally, the miniaturization of these analytical instruments for field application is also a challenge. In this study, we present a compact, real-time hydrogen fuel analyzer based on gas chromatography with a pulsed discharge helium ionization detector. Its dual-column system efficiently analyzes major impurities in hydrogen fuel in less than 30 min. Indicator species (CO, CO2, CH4, O2, N2, and additional hydrogen sulfide [H2S]) are determined by examining hydrogen production and supply processes. The analyzer's measurement capability is consistent with µmol/mol-level analysis, providing valuable real-time information for hydrogen infrastructure managers. Additionally, it can analyze H2S, a crucial marker of sulfur compounds acting as catalytic poisons in fuel cells. This real-time analyzer offers efficient, informed decision-making support for hydrogen infrastructure managers, enhancing the overall reliability of hydrogen fuel in fuel-cell electric vehicles.

Triboelectric Nanogenerators for the Masses: A Low-Cost Do-It-Yourself Pulsed Ion Source for Sample-Limited Applications.

Triboelectric nanogenerators (TENG) are useful devices for converting mechanical motion into electric current using readily available materials. Though the applications for these devices span across many fields, TENG can be leveraged for mass spectrometry (MS) as inexpensive and effective power supplies for pulsed nanoelectrospray ionization (nESI). The inherently discontinuous spray provided by TENG is particularly useful in scenarios where high sample economy is imperative, as in the case of ultraprecious samples. Previous work has shown the utility of TENG MS as a highly sensitive technique capable of yielding quality spectra from only a few microliters of sample at low micromolar concentrations. As the field of miniaturized, fieldable mass spectrometers grows, it remains critical to develop advanced ion sources with similarly small power requirements and footprints. Here, we present a redesigned TENG ion source with a sub-1000 USD material cost, lower power consumption, reduced footprint, and improved capabilities. We validate the performance of this new device for a diverse set of applications, including lipid double bond localization and native protein analysis.

Pulsed Direct Current Arc-Induced Nanoelectrospray Ionization Mass Spectrometry.

This study explores the innovative field of pulsed direct current arc-induced nanoelectrospray ionization mass spectrometry (DCAI-nano-ESI-MS), which utilizes a low-temperature direct current (DC) arc to induce ESI during MS analyses. By employing a 15 kV output voltage, the DCAI-nano-ESI source effectively identifies various biological molecules, including angiotensin II, bradykinin, cytochrome C, and soybean lecithin, showcasing impressive analyte signals and facilitating multicharge MS in positive- and negative-ion modes. Notably, results show that the oxidation of fatty acids using a DC arc produces [M + O - H]- ions, which aid in identifying the location of C═C bonds in unsaturated fatty acids and distinguishing between isomers based on diagnostic ions observed during collision-induced dissociation tandem MS. This study presents an approach for identifying the sn-1 and sn-2 positions in phosphatidylcholine using phosphatidylcholine and nitrate adduct ions, accurately determining phosphatidylcholine molecular configurations via the Paternò-Büchi reaction. With all the advantages above, DCAI-nano-ESI holds significant promise for future analytical and bioanalytical applications.

Characteristic Evaluation of Gas Chromatography with Different Detectors for Accurate Determination of Sulfur Hexafluoride.

Sulfur hexafluoride (SF6), which survives in the atmosphere for an extremely long period of time, is the most potent greenhouse gas regulated under the Kyoto Protocol. So, the accurate monitoring of atmospheric SF6 plays an important role in the study of the control policies for reducing greenhouse gas emissions. The instruments for SF6 measurement are typically calibrated using certified reference materials. The concentrations of the commercially available SF6 reference materials usually have a broad range, from 1 μmol/mol to 6000 μmol/mol. Some characteristics including sensitivity, linear range, relative standard deviation, and accuracy are crucial for the determination of SF6 in such a broad concentration range. Therefore, the selection of a proper detector for the accurate determination of SF6 with such a broad range is extremely important to establish a gas chromatography (GC) method for developing SF6 reference materials. In this paper, several typical GC methods with different detectors, including a thermal conductivity detector (TCD), a pulsed discharge helium ionization detector (PDHID), and a flame photometric detector (FPD), were carefully established for the accurate determination of SF6 with different concentrations. The results show that an FPD detector has a relatively narrow linearity range, thus a quadratic equation should be established for building a calibration curve. The PDHID and TCD have good linearity with coefficients of 1.0000 in the concentration range of 10-100 μmol/mol (using a PDHID), and 100-1000 μmol/mol (using a TCD), respectively. Further considering the measurement errors of indication results, the PDHID is suitable for SF6 measurement when the concentrations are below 100 μmol/mol, whereas the TCD is suitable for SF6 measurement when the concentrations are over 100 μmol/mol. These results provide useful guidance in choosing an appropriate GC detector for the accurate determination of SF6, which are especially very helpful for developing SF6 reference materials.

Disorder-induced heating as a mechanism for fast neutral gas heating in atmospheric pressure plasmas

Recent findings suggest that ions are strongly correlated in atmospheric pressure plasmas if the ionization fraction is sufficiently high ( ≳10−5 ). A consequence is that ionization causes disorder-induced heating (DIH), which triggers a significant rise in ion temperature on a picosecond timescale. This is followed by a rise in the neutral gas temperature on a longer timescale of up to nanoseconds due to ion–neutral temperature relaxation. The sequence of DIH and ion–neutral temperature relaxation suggests a new mechanism for ultrafast neutral gas heating. Previous work considered only the case of an instantaneous ionization pulse, whereas the ionization pulse extends over nanoseconds in many experiments. Here, molecular dynamics simulations are used to analyze the evolution of ion and neutral gas temperatures for a gradual ionization over several nanoseconds. The results are compared with published experimental results from a nanosecond pulsed discharge, showing good agreement with a measurement of fast neutral gas heating.

Super-heavy ion beams generated by a multi-PW femtosecond laser

The numerical investigations into the acceleration of superheavy ions driven by a multi-PW, 30 fs laser pulse with a peak intensity from 5 × 1022 to 2 × 1023 W/cm2 were carried out using an advanced 2D3V particle-in-cell code. The properties of laser-accelerated Au, Pb, Bi, and U ion beams, such as ionization and ion energy spectra, ion beam energies, angular distributions of the beam fluence, the ion pulse shapes, and peak intensities, were examined and compared. It was found that for a laser intensity of 1023 W/cm2, a common feature of the Au, Pb, Bi, and U ion beams was the dominance in the beam of Ne-like ions that carry the vast majority (≥90%) of the energy of all accelerated ions and have by far the highest mean and maximum ion energy. The Ne-like ion beams for Au, Pb, Bi, and U have almost identical angular fluence distributions and ion pulse shapes, as well as peak fluencies and intensities. However, the dependence of the parameters of the Ne-like ion beam on the laser intensity is different for ions with different masses. In the considered laser intensity range, the heaviest ions (U ions) ensured the achievement of the highest beam parameters, such as the mean and maximum ion energy, the ion beam energy, or the laser-to-ions energy conversion efficiency. The mono-charge superheavy ion beams demonstrated in this paper open the prospect for novel applications of heavy ions in high energy-density physics, nuclear physics, and possibly in other fields.

Laser isotope separation of 203Tl through pulsed laser optical pumping

Isotope separation of 203Tl through pulsed laser optical pumping into the 6s26p2P3/2∘ meta-stable state, followed by pulsed laser ionization, has been theoretically studied through density matrix formalism. The efficiency of the isotope separation process has been compared with the cw laser optical pumping followed by pulsed laser photoionization reported earlier. The effect of peak power density, bandwidth and number density of atoms on the degree of enrichment and the production rate has been systematically studied. The optimum parameters for the efficient laser isotope separation 203Tl have been derived. It has been shown that using this method, it is possible to produce about 1.5 kg/y of 203Tl isotope enriched to 90%.

Calcium Signal Analysis in the Zebrafish Heart via Phase Matching of the Cardiac Cycle.

Calcium signalling in the endocardium is critical for heart valve development. Calcium ion pulses in the endocardium are generated in response to mechanical forces due to blood flow and can be visualised in the beating zebrafish heart using a genetically encoded calcium indicator such as GCaMP7a. Analysing these pulses is challenging because of the rapid movement of the heart during heartbeat. This protocol outlines an imaging analysis method used to phase-match the cardiac cycle in single z-slice movies of the beating heart, allowing easy measurement of the calcium signal. Key features • Software to synchronise and analyse frames from movies of the beating heart corresponding to a user-defined phase of the cardiac cycle. • Software to measure the fluorescence intensity of the beating heart corresponding to a user-defined region of interest.