CRYOGENIC LOOP HEAT PIPES FOR THE COOLING OF SMALL PARTICLE DETECTORS AT CERN

Abstract

The loop heat pipe (LHP) is among the most effective heat transfer elements. Its principle is based on a continuous evaporation/condensation process and its passive nature does not require any mechanical devices such as pumps to circulate the cooling agent. Instead a porous wick structure in the evaporator provides the capillary pumping forces to drive the fluid [1]. Cryogenic LHP are investigated as potential candidates for the cooling of future small‐scale particle detectors and upgrades of existing ones. A large spectrum of cryogenic temperatures can be covered by choosing appropriate working fluids. For high luminosity upgrades of existing experiments installed at the Large Hadron Collider (LHC) (TOTEM) and planned ones (FP420) [2–3] being in the design phase, radiation‐hard solutions are studied with noble gases as working fluids to limit the radiolysis effect on molecules detrimental to the functioning of the LHP. The installation compactness requirement of experiments such as the CAST frame‐store CCD detector cooling system impels also the design of a compact shaped LHP [4]. This paper reports on the design and experimental results of a general purpose LHP for temperatures as low as 110 K, for which the performances were measured using a Gifford‐McMahon (GM) cooler as the cold source, combination envisaged for the cooling of future particle detectors.