He II heat exchanger test unit for the LHC inner triplet
The Inner Triplet Heat Exchanger Test Unit (IT-HXTU) is a 30-m long thermal model designed at Fermilab, built in US industry, fully automated and tested at CERN as part of the US LHC program to develop the LHC Interaction Region quadrupole system. The cooling scheme of the IT-HXTU is based on heat exchange between stagnant pressurized He II in the magnet cold mass and saturated He II (two-phase) flowing in a heat exchanger located outside of and parallel to the cold mass. The purposes of this test are, among others, to validate the proposed cooling scheme and to define an optimal control strategy to be implemented in the future LHC accelerator. This paper discusses the results for the heat exchanger test runs and emphasizes the thermal and hydraulic behavior of He II for the inner triplet cooling scheme.
Production status of the LHC inner triplet magnet system
The inner triplet magnet systems for the LHC provide the final focus of the two proton beams immediately before collision at the four interaction points in the machine. At both the high and low luminosity interaction regions, the quadrupole magnets composing the Q1 through Q3 optical elements are capable of operation at 215 T/m when cooled to 1.9 K, and subjected at the high luminosity interaction points to significant beam heating. The design and production of the system is the result of several years of international collaboration between laboratories and industries on three continents.
Spin label motion in fatty acids.
Spin labels dissolved in highly purified fatty acid systems exhibit nearly identical tumbling rates in liquid and solid phases. Even though the spin labels do not have the same molecular geometry as the lipid matrix the melting point of the matrix can be inferred by measurements of the temperature dependency of molecular motion.