title: Application of the double paddle oscillator for quantifying environmental, surface mass variation.
abstract: Sub-monolayer sensitivity to controlled gas adsorption and desorption is demonstrated using a double paddle oscillator (DPO) installed within an UHV (ultra-high vacuum) environmental chamber equipped within situfilm deposition, (multi)gas admission and temperature control. This effort is intended to establish a robust framework for quantitatively comparing mass changes due to gas loading and unloading on different materials systems selected or considered for use as mass artifacts. Our apparatus is composed of a UHV chamber with gas introduction and temperature control andin-situmaterials deposition for future materials testing enablingin situpreparation of virgin surfaces that can be monitored during initial exposure to gasses of interest. These tools are designed to allow us to comparatively evaluate how different materials gain or lose mass due to precisely controlled environmental excursions, with a long term goal of measuring changes in absolute mass. Herein, we provide a detailed experimental description of the apparatus, an evaluation of the initial performance, and demonstration measurements using nitrogen adsorption and desorption directly on the DPO.
authors.affiliation: Quantum Measurement Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA ; Joint Quantum Institute, University of Maryland, College Park, MD 20742, USA.
authors.forename: Haoyan
authors.initials: H
authors.lastname: Wei
authors.affiliation: Quantum Measurement Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
authors.forename: Joshua
authors.initials: J
authors.lastname: Pomeroy
keywords: Double paddle oscillator; gas adsorption and desorption; instability of mass artifacts; microbalance