The LHCb Inner Tracker

1. The LHCb Inner Tracker LHCb: is a single-arm forward spectrometer dedicated to B-physics acceptance: 15-300(250)mrad: The LHCb Inner Tracker covers the high particle density region near the beam pipe and the bending plane of the magnet in the tracking stations behind the magnet with Silicon Strip detectors. The total area of Silicon is ~4.3m2 • The Challenges • Unlike vertex detectors we have: • moderate spatial resolution requirement (~60mm) • moderate radiation environment. After 10 years: • 1 Mrad or 9·1012cm-2 of 1 MeV Neutron equiv. in IT • But we need to cover a large detector area: • minimize: R/O channels  large pitch O(200mm) • (limits charge collection) •  long strips 22cm(noise) • 40MHz, fast readout  (noise) • minimize material  “thin” sensors • (limits amount of charge) The Outer Tracker: covers the large surface area with straw tube detectors • The Inner Tracker Layout • The Inner Tracker consists of • 4 individual boxes per station • 4 layers per station: (2 stereo layers) 336 modules: 11 and 22cm long 129k readout channels on 4.3m2 silicon • The Inner Tracker: • silicon strip detectors • 1.3% of the acceptance • 20% of the tracks The Inner Tracker Silicon Module Carbon Fibre (CF) support produced out of high thermal conductive fibre used to cool the sensors and the detector box cooling “balcony” for mounting and positioning of the ladder on the supporting cooling rod which is connected to the liquid cooling system • Sensors • Kapton • Carbon Fibre • AIREX faom • Carbon Fibre • operation at ~5°C • liquid C6F14 cooling system for cooling readout hybrid and sensors • thermally conductive CF support • box enclosure lightweight isolation foam + Al foil for electrical shielding • the analog signals from the readout hybrids are sent via 5m copper cables to the service boxes outside of the acceptance where they are digitised readout hybrid with 3 Beetle chips in 0.25mm CMOS technology operating at 40MHz. The 128 channel front-end signals are pipelined for 160 bunch crossings. The output data are multiplexed on 4 readout ports allowing for a readout in 900ns after a trigger. p-n silicon micro-strip Hamamatsu sensors 384 AC coupled readout strips 108 mm long strips, 197mm pitch, w/p=0.25 320(410)mm thickness The Inner and Outer Tracker Support The Inner and Outer Trackers have individual rail systems on a common support structure. This allows individual access to both sub-detectors and their electronics Outer Tracker Inner Tracker box rail system Production of Inner Tracker Modules the readout hybrid is glued together with the pitch-adapter to the CF-support sensors are positioned according to their edges on a special jig, picked up by a vacuum tool and placed on the CF-support, where glue is applied using a glue dispenser bonding machine used to make the electrical connection between readout hybrid, pitch-adapter and sensors CF support bars Service boxes where the analog signals from the readout chip are digitised and then optically transmitted to the counting house where they are further processed  TELL1