| 摘要 |
PROBLEM TO BE SOLVED: To accurately measure the density of a very low temperature fluid without generating an error even in narrow electrode spacing, in an electrostatic capacity type density measuring device arranged with electrodes facing in a very low temperature fluid, such as slush hydrogen, for measuring a dielectric constant of the fluid based on a change of an electrostatic capacity between the electrodes, and for measuring a density of the fluid based on the resulting dielectric constant. SOLUTION: A plate electrode and cylindrical electrode are arranged facing inside a slush hydrogen tank 2. A change of an electrostatic capacity between these electrodes is measured by an LCR meter 8. The temperature of liquid hydrogen is reduced by evacuating the gas inside the vessel 2 by a vacuum pump 7 to generate slush hydrogen 3. A dielectric constant of the slush hydrogen 3 is measured, based on the change of the electrostatic capacity caused by existence of the slush hydrogen 3 between the electrodes, and a density of the slush hydrogen 3 is measured based on the resulting dielectric constant.
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