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Physicists Discover Flaws in Bean’s Superconductor Theory

University of Houston physicists report finding major theoretical flaws in the "Bean" or "Critical State Model," a generally accepted theoretical explanation of how a superconductor traps and holds a magnetic field. The team's research, published in the Journal of Applied Physics, reveals unexpected new behaviors favorable to practical applications, including...

LHC Restarted, Researchers Eye 2,700 Bunches per Beam

The Large Hadron Collider (LHC) resumed operations on March 25 when CERN researchers opened its doors to allow particles to travel around the ring for the first time since the year-end technical stop (YETS) began in December 2015. Several updates and interventions took place in LHC accelerators and beamlines during...

LCLS-II Upgrade Will Boost Power of World’s Brightest X-ray Laser

Construction is underway on a major upgrade to LCLS (Linac Coherent Light Source), a unique X-ray laser at the Department of Energy’s SLAC National Accelerator Laboratory. The project, known as LCLS-II, will add a second X-ray laser beam that’s 10,000 times brighter, on average, than the first one and fires...

NASA Completes JWST Cryogenic Testing

NASA researchers have completed cryogenic testing on the science instruments module for the James Webb Space Telescope (JWST). The module contains JWST's science cameras and spectrographs, and had been undergoing four months of monitoring inside a giant thermal vacuum chamber called the Space Environment Simulator (SES) at NASA's Goddard Space...

NASA Scientists Prepare Cold Atom Laboratory for ISS Mission

On a sun-drenched hill in Southern California's San Gabriel Mountains, researchers at NASA's Jet Propulsion Laboratory in Pasadena are making progress on an experimental facility that could create the coldest known place in the universe. It's called the Cold Atom Laboratory (CAL) and is expected to probe the wonders of...

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Mixed Refrigerant Cycles

Most cryogenic refrigeration systems, both large scale systems and cryocoolers, use helium as a working fluid. There are a number of advantages to helium, not the least of which is that helium remains a fluid down to the lowest achievable temperatures. In order to freeze helium, pressures of over 20...

Fountain Pumps and He II Phase Separators

Helium II (He II), the second liquid phase of the 4He isotope described in this column in Cold Facts Spring 2010 (http://2csa.us/he2), can be modeled as consisting of two interpenetrating fluids. One, the superfluid component, has zero viscosity and entropy and the other, the normal fluid component, has nonzero viscosity...

Turboexpanders

A vital technology in the refrigerators and liquefiers described in Cold Facts Volume 31 Number 3 is that of turboexpanders. These devices are rotating machines in which the process fluid (e.g., helium) does work against the turboexpander while moving from high pressure to a lower pressure and thus is cooled....

Primary Standards

Elie K. Track Hypres, Inc. elie@hypres.com http://www.hypres.com/ Primary standards involve the exact definition and realization of units of measurement for various quantities, time, length, mass, voltage, resistance, current, etc. International agreements based on the latest scientific knowledge define those units, and their realizations vary depending on the unit itself. For...

Shrink Fitting

Robin A. Rhodes Cryogenic Institute of New England, Inc. rrhodes@nitrofreeze.com Shrink fitting, (or “compression fitting” as it is sometimes called), is a method used to insert a pin or bushing into a housing or other assembly requiring an extremely tight tolerance fit. It can be used as an alternative to...

Telecommunications

From the Winter 2004 issue of Cold Facts magazine The recent M-Calc IV — 4th Industry Assessment workshop discussing military and commercial applications for low-cost cryocoolers, held in November in San Diego, highlighted progress being made in cryogenics as applied in telecommunications. The reliability and long lifetime of projects now...

Wind Tunnels

Dr. Robert Kilgore The development of the cryogenic wind tunnel is one of many significant breakthroughs in both cryogenics and wind-tunnel technology made during the past millennium. Interest in the development of high-speed commercial and military aircraft resulted in a review of problems of flow simulation in transonic wind tunnels...

An Issue of Pressure and Flow Rate in a Supply Tank

Please help solve this problem: A supply tank requires a vaporizer to generate sufficient pressure to pump stored fluid up into a vehicle or tank. The available head is limited as the tank level falls and it is important to minimize the system pressure drop to maintain the desired flow...

Using MLI on VJ Line Joints or Cryo Storage Tanks

When installing Multi Layer Insulation (MLI) blankets on VJ line joints or cryo storage tanks should they be wrapped and tied down tight or loose? These are usually pre-cut to size. Also should they have an access hole at the point of where the molecular sieve is installed to help...