Design and prototype studies of the TOTEM Roman pot detectors

The Roman pots of the TOTEM experiment at LHC will be equipped with edgeless silicon micro-strip detectors. A detector package consists of 10 detector planes cooled at - 15 ∘ C in vacuum. The detector resolution is 20 μ m , the overall alignment precision has to be better than 30 μ m . The detector planes are composed of a kapton hybrid glued on a substrate made of low expansion alloy, CE07 with 70% Si and 30% Al. An evaporative cooling system based on the fluorocarbon C 3 F 8 with oil-free compressors has been adopted. The throttling of the fluid is done locally through capillaries. A thermo-mechanical prototype has been assembled. The results fully match the requirements and the expectations of calculations. They show a low thermal gradient on the cards and a uniform temperature distribution over the 10 planes.