helium cooling
1.It consists of a 5T-138mm bore, superconducting background magnet, a pair of pulsed superconducting solenoids which can superimpose a dB/dt up to 10T/s during their discharge to the tested samples and a supercritical helium cooling system. This facility will be used to simulate the operating condition of CICC in tokamak S.C. magnet system which are subjected to the disturbances due to the poloidal field magnet pulsed and plasma disruption.
4.This paper introduces the method of how to simulate calculations for the current lead cooled down by helium gas, yielding some profitable results, including the minimum cooling power of liquid helium required per ampere for the current lead, the temperature distribution on it with various p(0), the optimum condition between the current I, the dimension of the lead L/S and the residual resistance ratio p(0), etc.
5.The big bang model, which states that almost 14 billion years ago the universe started expanding from a state of extremely high density and temperature, is able to explain galaxy motions, the abundance of hydrogen and helium, and the properties of the cosmic microwave background (CMB), the remnant heat from the expanding and cooling gas.
8.Consequently, the first chip-trap proposal, put forward by a group at the California Institute of Technology in 1995, involved cooling the entire chip to near absolute zero using a bulky and expensive liquid-helium refrigerator.
9.For our system, the magnet is immerged in a dewer and the upper surface of the dewer is thermally anchored to the second cold end of a two-stage pulse tube cooler with cooling power of 0.6W at 4.2K. During the cool-down process, helium gas is first liquefied by the pulse tube cooler and filled into the dewer.
