High voltage amplifier

Ting, Joseph W.; Peng, Wen-Ping; Chang, Hsiu-Chen

doi:10.1109/nssmic.2003.1351918

Cited by 2 publications

(1 citation statement)

References 2 publications

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“…A frequency-doubled pulsed Nd:YAG laser (532 nm and 30 mJ/pulse) irradiated the sample from the backside of the wafer. Desorbed charged particles were captured by the ion trap driven by a home-built audio frequency power amplifier (in a bipolar mode with voltage stability better than 100 ppm) and damped to the trap center by helium buffer gas (∼1 mTorr). The typical laser power density used was ∼1 × 10 8 W/cm 2 , which created a visible laser-ablated spot on the Si wafer.…”

Section: Methodsmentioning

confidence: 99%

Molar Mass and Molar Mass Distribution of Polystyrene Particle Size Standards

et al. 2005

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Monodisperse polystyrene microspheres and nanospheres are often used as particle size standards for calibration of size-measuring instruments. They are potentially useful as the mass standards for particle mass spectrometry as well. We demonstrated in this work that it is possible to achieve high-precision mass determination for single polystyrene spheres using a quadrupole ion trap. We introduced the particles into the trap by laser-induced acoustic desorption and probed them with light scattering. Mass-to-charge ratios of the individual particles were determined from applied trap-driving frequencies, voltage amplitudes and the observed starlike oscillatory trajectories projected on the radial plane. Creation of one-electron differentials through charge-state changes by electron bombardment allowed determination for the absolute mass of a single trapped particle to a precision better than 0.1%. Both molar mass and molar mass distribution were deduced from a large number of measurements for NIST polystyrene particle size standards (SRMs 1690 and 1691). Our results are in excellent agreement with the size measurement for the 0.895-microm spheres (NIST SRM 1690), but a small discrepancy (4%) in number-average mass was found for the 0.269-microm spheres (NIST SRM 1691).

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Section: Methodsmentioning

confidence: 99%