Design and optimisation of low heat load liquid helium cryostat to house cryogenic current comparator in antiproton decelerator at CERN

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

材料科学;物理学

Lees, A.^1 ; Koettig, T.^1 ; Fernandes, M.^1 ; Tan, J.^1

CERN, Accelerator Technology Department, Geneva 23

CH-1211, Switzerland^1

关键词: Absolute measurements;    Antiproton decelerator;    Continuous liquefaction;    Cryogenic current comparator;    Design challenges;    Liquid helium cryostats;    Magnetic field components;    Support systems;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/171/1/012033/pdf
DOI  :  10.1088/1757-899X/171/1/012033

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The Cryogenic Current Comparator (CCC) is installed in the low-energy Antiproton Decelerator (AD) at CERN to make an absolute measurement of the beam intensity. Operating below 4.2 K, it is based on a superconducting quantum interference device (SQUID) and employs a superconducting niobium shield to supress magnetic field components not linked to the beam current. The AD contains no permanent cryogenic infrastructure so the local continuous liquefaction of helium using a pulse-tube is required; limiting the available cooling power to 0.69 W at 4.2K. Due to the sensitivity of the SQUID to variations in magnetic fields, the CCC is highly sensitive to mechanical vibration which is limited to a minimum by the support systems of the cryostat. This article presents the cooling system of the cryostat and discusses the design challenges overcome to minimise the transmission of vibration to the CCC while operating within the cryogenic limits imposed by the cooling system.