arXiv subjects

Jennifer Wenzl

Publications and source records attributed to Jennifer Wenzl.

3 recordsLinked to original sources

arXiv2020

Demonstration of variable angle Super-Heterodyne Dynamic Light Scattering for measuring colloidal dynamics

We demonstrate a prototype light scattering instrument combining a frequency domain approach to the intermediate scattering function from Super-Heterodyning Doppler Velocimetry with the versatility of a standard homodyne Dynamic Light Scattering goniometer setup for investigations over a large range of scattering vectors. Comparing to reference experiments in correlation-time domain, we show that the novel approach can determine diffusion constants and hence hydrodynamic radii with high precision and accuracy. Possible future applications are discussed shortly.

cond-mat.soft↗

arXiv2019

Detection of atomic nuclear reaction products via optical imaging

In this paper we propose a new method for measuring the cross section of low yield nuclear reactions by capturing the products in a cryogenically frozen noble gas solid. Once embedded in the noble gas solid, which is optically transparent, the product atoms can be selectively identified by laser induced fluorescence and individually counted via optical imaging to determine the cross section. Single atom sensitivity by optical imaging is feasible because the surrounding lattice of noble gas atoms facilitates a large wavelength shift between the excitation and emission spectrum of the product atoms. The tools and techniques from the fields of single molecule spectroscopy and superresolution imaging in combination with an electromagnetic recoil separator, for beam and isotopic differentiation, allow for a detection scheme with near unity efficiency, a high degree of selectivity, and single atom sensitivity. This technique could be used to determine a number of astrophysically important nuclear reaction rates.

physics.ins-det↗

arXiv2018

Colloidal electro-phoresis in the presence of symmetric and asymmetric electro-osmotic flow

We characterize the electro-phoretic motion of charged sphere suspensions in the presence of substantial electro-osmotic flow using a recently introduced small angle super-heterodyne dynamic light scattering instrument (ISASH-LDV). Operation in integral mode gives access to the particle velocity distribution over the complete cell cross-section. Obtained Doppler spectra are evaluated for electro-phoretic mobility, wall electro-osmotic mobility and particle diffusion coefficient. Simultaneous measurements of differing electro-osmotic mobilities leading to asymmetric solvent flow are demonstrated in a custom made electro-kinetic cell fitting standard microscopy slides as exchangeable sidewalls. Scope and range of our approach are discussed demonstrating the possibility of an internal calibration standard and using the simultaneously measured electro-kinetic mobilities in the interpretation of microfluidic pumping experiment involving an inhomogeneous electric field and a complex solvent flow pattern.

cond-mat.soft↗