Experimental Study of Cooldown and Warmup of a UNK Superconducting Dipole
A number of calculational and experimental studied of cooldown to 4.5 K and warmup processes of the UNK superconducting dipoles have been carried out at IHEP. This paper presents some results on the experimental study of these processes, obtained for a 6-m cold-iron superconducting dipole. 232 temperature-sensitive elements arranged in 14 cross sections of the dipole were used to measure the temperature fields. Both routine technological processes and modes related to quenches were studied. Using the data on the detailed temperature distributions and the duration of the processes we could also conclude on the thermodynamic stresses in the helium cryostat pipes. The experimental results also made it possible to calibrate the three-dimensional model for calculational analysis of the thermal processes in the dipole.
For the model with the pipes connected to the cryostat flanges rigidly it took 12 hours to cool down the dipole and 24 hours to warm up it due to thermodynamic limitations. For the model with the aperture pipe having no such connections these times were 8.5 and 10 hours, respectively. This means that elimination of rigid connections, i.e. application of flexible compensating elements, allows one to avoid the inevitable adjustment of technological modes and to provide the required performance time both with the unit for mass calibration of dipoles and in a string of 110 dipoles of the UNK. The cooldown time of a SC dipole after an intentional quench at the experimental test facility did not exceed 10 minutes.
KeywordsTest Facility Technological Mode Helium Cryostat Dipole Cross Section Rigid Coupling
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- 1.A. G. Abramov et al. Simulation of Cooldown and Warmup Processes of SC UNK Dipoles //Proceed, of X Al-Union High Energy Charged Part. Accel. — Dubna, 1986. — V. 2. -P. 296–299.Google Scholar
- 2.A.I.Ageyev et al. Test Facility for Full-Scale SC UNK Magnets // ICEC–10.–Finland, 1984.– P. 742–745.Google Scholar
- 3.V. I. Datskov. Technical Thermometers Based on Serial TBO — Type Resistors. -Dubna, 1983. — 8 p. (Preprint) JINR, 8–83–717.Google Scholar