Investigation of the electrical properties of standard and low-gas-flow ICPs using novel probes for the direct measurements of RF voltage and current in the load coil and the corresponding calculation of the ICP power

Abstract

New probes for the direct measurement of high radio-frequency (RF) voltage and current in the load coil of an inductively coupled plasma (ICP) are presented. Based on these measurements, a method for the calculation of power in the ICP is developed. Electrical parameters of the ICP are measured for a wide range of operational conditions in a standard ICP torch with wet aerosol introduction. Further, changes of the electrical parameters are monitored when operating the ICP with a very low argon flow rate of only 0.6 L min À1 using a so-called "Static High-Sensitivity ICP" (SHIP) torch. Direct measurements with the new RF probes allow following the evolution of plasma properties as a function of time. Noteworthy, it is found that there is a strong correlation between the plasma power and temperature changes in the RF generator itself. Depending on the plasma parameters, the measured plasma power was shown to differ significantly from the applied power (in the vendor software settings).

Force-based analysis of vortexes in atmospheric pressure ICPs

“…In the present paper a 2D model developed earlier [22] was used for the plasma simulations. It was successfully applied for simulations of SICPs and is in good agreement with experimentally measured electrical current, plasma power [20][21][22] and plasma temperatures [21] over a wide range of geometries and operational conditions of the SICPs.…”

“…Among other plasma sources, atmospheric pressure inductively coupled plasmas (ICPs) are characterized by high enthalpy and plasma density, an absence of electrodes resulting in a high purity of the plasma, and flexibility of parameters. Because of this the ICPs have found strong practical applications in the processing of various substances, namely in the spheroidization of powder particles ([1-8] and references therein), the production of nanoparticles ( [9][10][11][12][13][14][15][16] and references therein), and as a source for atomic analysis ( [17][18][19][20][21][22][23][24][25][26][27] and references therein). The first two types are denoted here as technological ICPs (TICPs) while the last type is a spectroanalytical ICP (SICP).…”

Conical Torch: The Next-Generation Inductively Coupled Plasma Source for Spectrochemical Analysis

“…Instead, some researchers tried building the torch from other materials (mostly h-BN) instead of quartz. , However, these materials contaminate the plasma at high temperatures and are not transparent as required for OES. Alternatively, other researchers used water/air to cool the torch wall. ,− , Water cooling was very soon rejected because it lowers the sensitivity of plasma and has possible disastrous consequences in case of malfunction. Air-cooled torches, on the other hand, suffer from plasma contamination due to entrapment of air.…”

“…Alternatively, other researchers used water/air to cool the torch wall. 17,[19][20][21][22][23][24][25][26][27][28]34 Water cooling was very soon rejected because it lowers the sensitivity of plasma and has possible disastrous consequences in case of malfunction. Air-cooled torches, on the other hand, suffer from plasma contamination due to entrapment of air.…”

“…The popularity of the Fassel torch over similar torches − is due to its lower consumption of argon gas and radio frequency (RF) power, which are both considered favorable economic factors. The same factors later encouraged many researchers to improve the Fassel torch through various optimization procedures, , building the torch with materials other than quartz, , using alternative gases such as helium or nitrogen, − external cooling with air/water, ,− enhancing the swirling flow pattern inside the torch, ,− and size reduction. , …”