Abstract. In this study the charging efficiency of a radioactive and a non-radioactive plasma bipolar diffusion charger (Gilbert Mark I plasma charger) for sub-12 nm particles has been investigated at various aerosol flow rates. The results were compared to classic theoretical approaches. In addition, the chemical composition and electrical mobilities of the charger ions have been examined using an atmospheric pressure interface time-of-flight mass spectrometer (APi-TOF MS). A comparison of the different neutralization methods revealed an increased charging efficiency for negatively charged particles using the non-radioactive plasma charger with nitrogen as the working gas compared to a radioactive americium bipolar diffusion charger. The mobility and mass spectrometric measurements show that the generated bipolar diffusion charger ions are of the same mobilities and composition independent of the examined bipolar diffusion charger. It was the first time that the Gilbert Mark I plasma charger was characterized in comparison to a commercial TSI X-Ray (TSI Inc, Model 3088) and a radioactive americium bipolar diffusion charger. We observed that the plasma charger with nitrogen as the working gas can enhance the charging probability for sub-10 nm particles compared to a radioactive americium bipolar diffusion charger. As a result, the widely used classical charging theory disagrees for the plasma charger and for the radioactive chargers with increased aerosol flow rates. Consequently, in-depth measurements of the charging distribution are necessary for accurate measurements with differential or scanning particle sizers for laboratory and field applications.

Performing propagating spin-wave spectroscopy of thin films at millikelvin temperatures is the next step toward the realization of large-scale integrated magnonic circuits for quantum applications. Here, we demonstrate spin-wave propagation in a [Formula: see text]-thick yttrium-iron-garnet (YIG) film at temperatures down to [Formula: see text], using stripline nanoantennas deposited on YIG surface for electrical excitation and detection. The clear transmission characteristics over the distance of [Formula: see text] are measured and the extracted spin-wave group velocity and the YIG saturation magnetization agree well with the theoretical values. We show that the gadolinium-gallium-garnet (GGG) substrate influences the spin-wave propagation characteristics only for the applied magnetic fields beyond [Formula: see text], originating from a GGG magnetization up to [Formula: see text] at [Formula: see text]. Our results show that the developed fabrication and measurement methodologies enable the realization of integrated magnonic quantum nanotechnologies at millikelvin temperatures.

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Abstract. In this study the charging efficiency of a radioactive and a non-radioactive plasma neutralizer (Gilbert Mark I plasma charger) have been investigated at various aerosol flow rates. The results were compared to classic theoretical approaches. In addition, the chemical composition and electrical mobilities of the charger ions have been examined using an atmospheric pressure interface – time-of-flight mass spectrometer (APi-TOF MS). A comparison of the different neutralization methods revealed an increased charging efficiency for negatively charged particles using the non-radioactive plasma charger with nitrogen as working gas. The mobility and mass spectrometric measurements show that the generated neutralizer ions are of the same mobilities and composition independent of the charging mechanism. It was the first time that the Gilbert Mark I plasma charger was characterized in comparison to the standard TSI X-Ray (TSI Inc, Model 3088) and a radioactive americium neutralizer. We observed that the plasma charger with nitrogen as working gas can enhance the charging probability for sub-10 nm particles. Consequently, the limit of detection of differential or scanning mobility particle sizers can be increased down towards to smaller sizes with the Gilbert Mark I plasma charger.

List of Tables S1 Aerosol flow dependent charging efficiency measurements for different neutralizers with negatively (-) and positively (+) charged silver (Ag) seeds. In addition the investigated working gas and aerosol flow conditions for the Plasma charger