The Kelvin temperature scale is the principal temperature scale used in cryogenics and science. The kelvin is also one of the seven base units in the Système International d’Unités (SI) and is the unit of thermodynamic temperature. Thermodynamic temperature is a fundamental physical quantity (like mass, length or electrical current) and must equal zero at … Continue reading Kelvin Temperature Scale
Month: September 2011
The Joule-Thomson (JT) effect is a thermodynamic process that occurs when a fluid expands from high pressure to low pressure at constant enthalpy (an isenthalpic process). Such a process can be approximated in the real world by expanding a fluid from high pressure to low pressure across a valve. Under the right conditions, this can … Continue reading Joule-Thomson Effect
One of the challenges of using superconducting magnets is the connection of the magnet to a room temperature power supply. This is accomplished via current leads. The trick is that current leads should ideally have a low heat leak, since they connect room temperature to cryogenic temperature, while at the same time they should have … Continue reading Current Leads
Multilayer insulation (also referred to as superinsulation) is a key component in the reduction of heat leak to cryogenic systems due to thermal radiation. MLI consists of a series of uncooled reflective surfaces placed in the vacuum space between two surfaces, one warmer than the other. Generally speaking, for ideal systems the reduction in thermal … Continue reading Multilayer Insulation
Transfer lines may in some real sense be thought of as the cryogenic fluid analogy of current leads. While current leads carry electrical power to where it’s required in a cryogenic system, transfer lines do the same with cryogenic fluids. Transfer lines range in complexity from very simple U-tubes containing only one fluid line to … Continue reading Transfer Lines
Zero Boil Off cryostats are those that contain liquid cryogens but are designed to eliminate or vastly reduce the boil off of the liquid. These cryostats combine some of the advantages of Cryogen-Free systems (e.g. ease of use and long operational lifetime) with the advantages associated with a reservoir of liquid cryogens. Such a reservoir can … Continue reading Zero Boiloff
Cryomodule is a term that is most commonly used to refer to cryostats that contain superconducting radio frequency (SRF) cavities. Such cavities are used to accelerate charged particle beams and are a major component of modern particle accelerators. Using the term cryomodule to refer to cryostats containing SRF cavities appears to stem from the original … Continue reading Cryomodule
Adiabatic Demagnetization Refrigeration
Reaching temperatures below 1K requires different techniques than the various helium gas cycles found in large scale refrigeration plants and small cryocoolers. One of these techniques is Adiabatic Demagnetization Refrigeration (ADR). This technique takes advantage of the fact that the entropy of paramagnetic materials in a magnetic field is lower than when no field is present. … Continue reading Adiabatic Demagnetization Refrigeration
A cryogen is any fluid that operates at cryogenic temperatures (below roughly 150K – 120K). Using this definition, helium gas at 40K is a cryogen. Another more restrictive definition is to use cryogen to refer specifically to liquids at cryogenic temperatures. This is generally how it is used in the term cryogen-free. Thus, a cryogen-free … Continue reading Cryogen-Free
Cryostats and Cryocoolers
A cryostat is any device designed to maintain things (including fluids) at cryogenic temperatures. In general usage, cryostats tend to be passive devices rather than providing active cooling. In this usage, cryostats keep things cold by thermally isolating them from room temperature. This generally is accomplished by a combination of vacuum insulation, thermal radiation shields … Continue reading Cryostats and Cryocoolers
Helium II (He II) refers to the second liquid phase of the most abundant helium isotope (4He). Helium II is also referred to as superfluid helium. Helium II occurs once the temperature of the liquid helium drops below 2.17K. The phase transition between the first liquid phase of Helium (referred to as Helium I) and … Continue reading Helium II
AMSC filing criminal and civil complaints against Sinovel
American Superconductor Corporation has announced that it is taking a series of legal actions against Sinovel Wind Group Co. Ltd. (Sinovel).
GE to develop wind turbine generator based on MRI magnet technology
With the wind industry moving toward larger wind turbine platforms in the future, GE Global Research, the technology development arm of the General Electric Company, has announced it has begun work on the first phase of a 2-year, $3 million project from the US Department of Energy to develop a next generation wind turbine generator that could support large-scale wind applications in the 10-15MW range.
Air Products participates in international research for food freezing, chilling
Air Products and the Grimsby Institute have announced a collaborative international research program to support the creation of best practice guidelines for food freezing and chilling.
Naji Skaf appointed CEO of Gulf Cryo
Naji Skaf has been appointed as Chief Executive Officer of Gulf Cryo.
Webb Telescope’s MIRI flight instrument completes cryogenic testing
A pioneering camera and spectrometer that will fly aboard NASA's James Webb Space Telescope has completed cryogenic testing designed to mimic the harsh conditions it will experience in space.
Novel magnetic, superconducting material opens new possibilities in electronics
Scientists have reached a crucial milestone that could lead to a new class of materials with useful electronic properties.
CRESST uncovers hint of dark matter
Physicists are finally closing in on dark matter, the elusive substance thought to make up most of the matter in the universe. Either that, or they’re being misled by some unknown source of error.
New superconductor fibers carry 40 times more electricity
Wiring systems powered by highly efficient superconductors have long been a dream of science, but researchers have faced such practical challenges as finding pliable and cost-effective materials. Now researchers at Tel Aviv University (TAU) have found a way to make an old idea new with the next generation of superconductors.