The formation of titanium nanoparticles (NPs) in a high-voltage electric discharge between titanium electrodes in liquid xenon at a temperature of –105°C has been observed. It has been shown that these titanium nanoparticles have a spherical shape with an average diameter of <50 nm and they possess high chemical activity. This makes it possible when a relative mass concentration of NP reaches ~10 –6 to efficiently purify xenon from electronegative impurities for its use as a working medium for a new generation of high-efficiency nuclear radiation detectors.

AbstractThe formation of titanium nanoparticles (NPs) in a high-voltage electric discharge between titanium electrodes in liquid xenon at a temperature of –105°C has been observed. It has been shown that these titanium nanoparticles have a spherical shape with an average diameter of <50 nm and they possess high chemical activity. This makes it possible when a relative mass concentration of NP reaches ~10^–6 to efficiently purify xenon from electronegative impurities for its use as a working medium for a new generation of high-efficiency nuclear radiation detectors.

A procedure for spark-discharge purification of a liquid xenon sample with a mass of 55 kg is described. The average lifetime of ionization electrons before capture by electronegative impurities in liquid xenon increased from ≤ 0.1 μs to ≥ 50 μs for an electric field of 50–500 V/cm as a result of the procedure. The xenon purified with this method is intended for use in the RED-100 detector for observation of the process of coherent elastic neutrino scattering off xenon nuclei.

Results are provided for a study in a laboratory test unit of the adsorption dynamics for krypton, xenon, ethane and nitrogen hemioxide (lower oxide) from air in two-layer equipment simulating an industrial adsorber of a combined purification unit (CPU) of a contemporary air separation unit (ASU). As a result of the studies, it is established that the loss of krypton in a CPU is insignificant (about 0.25%) and it is mainly determined by the presence of this component in the gas phase (air) at the end of the purification stage before the start of switching over adsorbers. The loss of xenon is more marked and it depends on the ratio of the calculated adsorber operating time (before the start of the breakthrough carbon dioxide) to the actual adsorber operating time in the purification stage. According to experimental data, the maximum loss of xenon is about 8%. The data obtained point to a marked reduction in the loss of gases in a CPU compared with regenerators used in old ASU schemes within which the losses were about 10–11% for krypton and 25–30% for xenon. It has been established by experiment that during operation of adsorbers of an industrial CPU about 18% of nitrogen hemioxide and 10% ethane is retained within them, but methane is hardly retained. The data obtained may be used in designing units for primary enrichment of krypton and xenon in an ASU.