Pulsed Trigger Research Articles

Study of trigger mechanisms of a pseudospark switch configuration with a steady-state auxiliary glow discharge

This paper presents data on investigation of the pseudospark switch whose trigger unit uses a low-current auxiliary glow discharge with hollow cathode and hollow anode. The electrode system of this unit communicates with the main high-voltage gap of the switch due to the aperture in the flat part of one of the trigger electrodes. It is shown that when the electrode with the aperture plays of role of the hollow cathode of the auxiliary discharge, a low parasitic current through the aperture is provided by the ion flow. This ion current does not practically influence on the static breakdown voltage of the main gap. Applying the trigger pulse between the trigger electrodes leads to the pulsed trigger discharge with an enhanced current. At a negative polarity of the trigger pulse, the cavity with aperture turns out into the hollow anode so that the current is able to be intercepted through the aperture to the grounded cavity of the main gap. The plasma is generated in the cavity and the switch is triggered. With the proper selection of the geometry of the trigger electrodes, the delay time to trigger at a level of several tens of nanoseconds is achievable.

Inkjet‐Printed Ag/a‐TiO2/Ag Neuromorphic Nanodevice Based on Functionalized Ink

This study aims to contribute to the burgeoning field of brain‐inspired computing by expanding it beyond conventional fabrication methods. Herein, the obstacles toward the effective inkjet printing process are encountered and the electrical characteristics are explored, providing new insights into the reliability aspects of fully printed Ag/a‐TiO2/Ag electronic synapses. The versatility of the approach is further enhanced by the highly stable in‐house‐developed a‐TiO2 ink, exhibiting optimal shelf life of five months and repeatable jetting, producing layers with nanoscale thickness resolution. Most importantly, device electrical characterization reveals synaptic dynamics, leading to activity‐dependent conductance state retention and adaptation characteristics, implying inherent learning capabilities. The synaptic dynamics are attained by solely adjusting the duty cycle of the applied pulsed voltage trigger, while keeping amplitude and polarity fixed, a method readily compatible with realistic applications. Furthermore, I–V analysis demonstrates a dynamic range dependence on a‐TiO2 layer thickness and conduction mechanism that is akin to the conventionally developed electronic TiO2 synapses. The developed devices provide a time‐ and cost‐effective ecologically benign alternative toward biomimetic signal processing for future flexible neural networks.

Deterministic generation of single soliton Kerr frequency comb in microresonators by a single shot pulsed trigger.

Kerr soliton frequency comb generation in monolithic microresonators recently attracted great interests as it enables chip-scale few-cycle pulse generation at microwave rates with smooth octave-spanning spectra for self-referencing. Such versatile platform finds significant applications in dual-comb spectroscopy, low-noise optical frequency synthesis, coherent communication systems, etc. However, it still remains challenging to straightforwardly and deterministically generate and sustain the single-soliton state in microresonators. In this paper, we propose and theoretically demonstrate the excitation of single-soliton Kerr frequency comb by seeding the continuous-wave driven nonlinear microcavity with a pulsed trigger. Unlike the mostly adopted frequency tuning scheme reported so far, we show that an energetic single shot pulse can trigger the single-soliton state deterministically without experiencing any unstable or chaotic states. Neither the pump frequency nor the cavity resonance is required to be tuned. The generated mode-locked single-soliton Kerr comb is robust and insensitive to perturbations. Even when the thermal effect induced by the absorption of the intracavity light is taken into account, the proposed single pulse trigger approach remains valid without requiring any thermal compensation means.

Investigation of high-voltage pulse trigger generator based on photo-conductive semiconductor switch

The trigger to generate high-voltage pulse is one of the most important parts in a pulsed-power system, especially for the conduction characteristics of the main switch. However, traditional triggers usually have the drawbacks of large structure and worse long-term working stability, which goes against the demands of pulsed-power system miniaturization and stability. In the paper, a pulse trigger using photo-conductive semiconductor switch was developed, which is of small size, stable performance and steep leading edge of the output pulse rise. It is found that the output trigger pulse rise time is 14 ns, and the jitter of 20 shots is 330 ps. Applying the designed pulsed trigger in a field distortion switch and a triggered vacuum switch, experiments show that the switches could be triggered stably with reduced jitter.

低抖动快前沿重复频率高压脉冲触发源研制

低抖动快前沿重复频率高压脉冲触发源研制

多间隙气体开关触发放电过程及击穿抖动

多间隙气体开关触发放电过程及击穿抖动

六间隙串联气体开关触发放电过程

六间隙串联气体开关触发放电过程

High power repetitive TEA CO2 pulsed laser

A high power repetitive spark-pin UV-preionized TEA CO2 laser system is presented. The discharge for generating laser pulses is controlled by a rotary spark switch and a high voltage pulsed trigger. Uniform glow discharge between two symmetrical Chang-electrodes is realized by using an auto-inversion circuit. A couple of high power axial-flow fans with the maximum wind speed of 80 m/s are used for gas exchange between the electrodes. At a repetitive operation, the maximum average output laser power of 10.4 kW 10.6 μm laser is obtained at 300 Hz, with an electro-optical conversion efficiency of 15.6%. At single pulsed operation, more pumping energy and higher gases pressures can be injected, and the maximum output laser energy of 53 J is achieved.

Characteristics and diagnostics of an ultrahigh vacuum compatible laser ablation source for crossed molecular beam experiments

We present the design and the characteristics of an ultrahigh vacuum compatible laser ablation source which can be operated in a crossed molecular beam machine at pressures as low as 10−9Torr. This unit provides intense supersonic beams of up to 3×1013cm−3 reactant species (carbon atoms, dicarbon, and tricarbon) in the interaction region of a crossed molecular beam machine. Practical delay time windows between the pulsed valve releasing the seeding gas and the laser have been determined to be between 16 630 and 16645μs, i.e., firing the laser 150–165μs after the 80μs pulsed valve trigger. The concentration of the dicarbon and tricarbon clusters can be maximized/minimized by adjusting the laser focus (a tighter laser focus leads to an enhanced atomic carbon component) and the laser power (multiphoton dissociation). We achieved stable peak velocities between 800 and 3800ms−1 and speed ratios S of up to 6.

The characteristics of pulsed hollow cathode discharges used for pseudospark switch triggering

The complex interaction between the trigger discharge and the main switch discharge in high-power gas discharge switches influences both the switching characteristics, and the switch and trigger lifetime. Any attempts to improve either of these parameters has to take into account the pressure and geometry dependence of a particular trigger geometry. Yet, although not very intensely investigated in detail for this particular purpose, pulsed hollow cathode discharges are commonly used for low-pressure gas discharge triggering as in pseudospark switches. Measurements of the electron current flowing to the cathode backplane of a pseudospark switch from the pulsed hollow cathode trigger discharge show that maximum current densities are peaked around the symmetry axis of the trigger electrode, an effect which is more pronounced at low pressures. Delayed (and slowed-down) increase of the current density at larger radii leads to increasing delay and jitter, provided the trigger coupling holes in the cathode backplane are located off-axis. The electron current density increases with decreasing diameter of the trigger electrode, and with increasing pressure of the working gas. In addition, it is shown that a preionization (keep-alive) current in the trigger electrode region shows a distinct influence on the trigger current distribution, proving that there exists an optimum keep-alive current depending on the geometry and gas pressure.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A self-crowbar switch for a gas-puff z-pinch driven by a pulsed power generator

A self-crowbar switch for a gas-puff z-pinch, driven by a pulsed power generator with output voltage 600 kV, pulse width 70 ns, and characteristic impedance of 3 Ω, has been built and tested successfully. Discharges with pulsed gas injection are placed into four groups dependent on the delay between the pulsed power generator trigger time and the gas-puff trigger time. For short delay times (&amp;lt;2.8 ms), vacuum discharge occurs. For moderate delay times (2.8–3.8 ms), a z-pinch plasma is produced without using the self-crowbar switch, and the plasma exists for a much longer time than the voltage pulse, that is, 700 ns compared to 70 ns. For relatively longer delay times (3.8–6 ms), the self-crowbar switch operates, and the decay time of the current becomes approximately 2.5 μs. Moreover, a z-pinch occurs after self-crowbarring. For long delay times (&amp;gt;6 ms), a z-pinch does not occur. The self-crowbar switch is believed to operate by photoionization of puffed gas which has reached the switch region.