Experimental study on heat transfer through a few layers of multilayer insulation from 300 K to 4.2 K

26th International Cryogenic Engineering Conference & International Cryogenic Materials Conference 2016

材料科学;物理学

Zong, Zhanguo^1 ; Ohuchi, Norihito^1 ; Tsuchiya, Kiyosumi^1 ; Arimoto, Yasushi^1 ; Yamaoka, Hiroshi^1

High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki

305-0801, Japan^1

关键词: Correction coil;    Cryogenic measurement;    Interaction region;    Multi-layer insulation;    Operation temperature;    Quadrupole magnets;    Space constraints;    Thermal conduction;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/171/1/012089/pdf
DOI  :  10.1088/1757-899X/171/1/012089

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The final focusing magnet system at the SuperKEKB interaction region has been designed under stringent space constraints and consists of 8 main Superconducting (SC) quadrupole magnets, 4 compensation SC solenoids, and 43 SC correction coils. SC correction coils are directly wound on the inner containment tubes of liquid helium (LHe) vessels, which serve as support bobbins for SC cables. Beam pipes, which are kept at room temperature (∼300 K), are inserted into the cold bores of the vessel inner tubes. Between them, the minimal radial gaps are only 3.5 mm. Heat transfer from the warm beam pipes causes the raised operation temperatures of SC cables and increases heat leaks into cryostats. Multilayer insulation (MLI) is adopted to reduce heat flux in the narrow gaps. MLI performance as a function of the layer number was studied with a vertical anti-cryostat of dedicated design. The measurements were carried out by a calorimeter of thermal conduction and a modified LHe boil-off method. This paper presents the cryogenic measurement system and discusses the experimental results for the cryostats of the SuperKEKB final focusing SC magnets.