Related papers: Reducing the hydrogen content in liquid helium
Liquid Helium is used widely, from hospitals to characterization of materials at low temperatures. Many experiments at low temperatures require liquid Helium, particularly when vibration isolation precludes the use of cryocoolers and when…
We have investigated the adsorption and desorption of helium near its liquid-vapor critical point in silica aerogels with porosities between 95% and 98%. We used a capacitive measurement technique which allowed us to probe the helium…
Recent helium shortages and helium price increases have lead to an increased emphasis being placed on conserving helium. The need to conserve helium must be balanced with need to maintain the high levels of purity necessary to prevent…
Recent experiments have suggested that, at low enough temperature, the homogeneous nucleation of bubbles occurs in liquid helium near the calculated spinodal limit. This was done in pure superfluid helium 4 and in pure normal liquid helium…
Equilibrium properties of hydrogen-helium mixtures under conditions similar to the interior of giant gas planets are studied by means of first principle density functional molecular dynamics simulations. We investigate the molecular and…
Helium Purification System is an important sub-system in the Accelerator Driven Subcritical System of the Institute of High Energy Physics(IHEP ADS). The purifier is designed to work at the temperature of 77K. The purifier will work in a…
We describe a helium source cell for use in cryogenic experiments that is hermetically sealed $in$ $situ$ on the cold plate of a cryostat. The source cell is filled with helium gas at room temperature and subsequently sealed using a cold…
It is generally assumed that solid hydrogen will transform into a metallic alkali-like crystal at sufficiently high pressure. However, some theoretical models have also suggested that compressed hydrogen may form an unusual two-component…
Cryogenic transmission electron microscopy has revolutionized structural biology and materials science, but achieving temperatures below the boiling point of liquid nitrogen remains a long-standing aspiration. We introduce an ultra-cold…
Alkali atoms trapped in solid hydrogen matrices have demonstrated ultralong electron spin coherence times, and are promising as quantum sensors. Their spin coherence is limited by magnetic noise from naturally-occurring orthohydrogen…
The properties of liquid helium have always been a fascinating subject to scientists. The phonon theory of liquids taking into account liquid non-static shear rigidity is employed here for studying internal energy and heat capacity of…
The solubility of helium in liquid metals is a knowledge of fundamental importance in the design of the future nuclear fusion reactors, since the formation of helium bubbles inside the breeding blankets of the reactors can be a threat to…
We describe a set-up for studying adsorption of helium in silica aerogels, where the adsorbed amount is easily and precisely controlled by varying the temperature of a gas reservoir between 80 K and 180 K. We present validation experiments…
We have investigated the formation of helium droplets in two physical situations. In the first one, droplets are atomised from superfluid or normal liquid by a fast helium vapour flow. In the second, droplets of normal liquid are formed…
Next-generation gravitational wave observatories are expected to use cryogenically cooled, pendulum-suspended 200 kg test mass mirrors from a crystalline material such as crystalline silicon. During operation of the observatories, these…
In laboratory experiments we observe that ice particles (\leq100 \mu m) entrained in a low pressure atmosphere (~1 mbar) get trapped by temperature gradients between three reservoirs at different tempertature. Confining elements are a…
Liquid helium under negative pressure represents a unique possibility for studying the macroscopic quantum nucleation phenomena in condensed media. We analyze the quantum cavitation rate of single electron bubbles at low temperatures down…
Equilibrium properties of hydrogen-helium mixtures under thermodynamic conditions found in the interior of giant gas planets are studied by means of density functional theory molecular dynamics simulations. Special emphasis is placed on the…
The extremely low solubility of helium in liquid metals may lead to rapid supersaturation, promoting spontaneous formation of helium bubbles by nucleation. Once nucleated, the stability of these bubbles is governed by the properties of the…
Next-generation cryogenic transmission electron microscopes (TEM) aim to achieve high-resolution imaging at ultracold sample temperatures (< 90 K) and over extended hold times. Lower temperatures enable atomic-scale characterization with…