Measuring the mutual diffusion coefficient of heavy water in normal water using a double liquid-core cylindrical lens

Weidong Meng,Yan Xia,Xiaoyun Pu,Yan Chen

doi:10.1038/s41598-018-30650-z

Abstract

The mutual diffusion coefficient of heavy water in normal water is measured over a temperature range of 20 to 40 °C using a novel method called the shift of equivalent refractive index slice (SERIS). The measured values range from 1.9086 × 10−5 to 3.0860 × 10−5 cm2/s and fit the Arrhenius equation well, and the calculated data from the equation are consistent with the literature values obtained by the interference method. The SERIS method is based on a double liquid-core cylindrical lens (DLCL); the front liquid core of the DLCL is used as both a liquid diffusion cell and a key imaging lens, and the resolvable minimum of liquid refractive index is δn = 6.15 × 10−5. The rear liquid core is used as an aplanatic lens, and the transversal spherical aberration is less than 1 μm. The SERIS method provides a new way to measure mutual diffusion coefficients of liquid and has the following advantages: visual measurement, use of a simplified device, and easy operation.

Highlights

Heavy water, which is used as a moderator and coolant in nuclear reactors, plays an important role in the production of nuclear energy[1]; as an isotope tracer material, heavy water is used to detect changes in chemical and physiological activities[2]
For the double liquid-core cylindrical lens (DLCL) used, Δf ≥ 306.9 μm in the range of n = 1.3282 to 1.3330 when n′ is fixed at 1.3990, δf < 99.3 μm, and δn is smaller than 6.15 × 10−5 and is satisfied fully in terms of the experimental requirement
The first question is how should the liquid that fills the rear liquid core of the DLCL be chosen? The rear liquid core is used to eliminate the spherical aberration (SA) caused by the front liquid core, which is the main aberration in the measurement

Summary

Introduction

Heavy water (deuterium oxide, D2O), which is used as a moderator and coolant in nuclear reactors, plays an important role in the production of nuclear energy[1]; as an isotope tracer material, heavy water is used to detect changes in chemical and physiological activities[2]. The traditional methods for measuring the D value of heavy water in normal water include interferometry[7], a diaphragm cell[8], Taylor dispersion[9] and nuclear magnetic resonance (NMR)[5]. NMR can only measure certain substances[5] To overcome these disadvantages, we have designed and fabricated a non-symmetrical liquid-core cylindrical lens[12,13] that can be used to measure the liquid diffusion coefficient quickly and accurately and can observe dynamic diffusion processes directly[12,13]. Using the DLCL, the D values of heavy water in normal water at a temperature range from 20 to 40 °C have been measured by a novel method called the shift of equivalent RI slice (SERIS), and the measured D values are fitted by the Arrhenius equation[15]. Using the DLCL and a CMOS camera, the entire diffusion process is visualized and displayed in the attached Visualization file

Methods

Results

Conclusion