Speaker
Description
The LHCb experiment is designed to study B-decays at the LHC, and as such is constructed as a forward spectrometer. The large particle density in the forward region poses extreme challenges to the subdetectors, in terms of hit occupancies and radiation tolerance.
To accurately and efficiently detect the charged decay particles in the high-density particle environment of the LHC the Outer Tracker (OT) has been constructed. The OT is a gaseous straw tube detector, consisting of 53,760 straw tubes, covering an area of 360 m2 of double layers.
A the time of detector construction in the years 2004-2006, worrying ageing effects were observed. The results of extensive studies performed between 2005 and 2012 regarding the ageing phenonemon, the underlying cause and the mitigation methods will be discussed.
A remarkable radiation resistance of this sensitive gas detector is reported. Unlike most other subdetectors in LHCb, constructed with various technologies, no sign of ageing was finally observed after having received a total dose corresponding to about 400 mC/cm in the hottest region.
References:
[1] S. Bachmann, N. Tuning, et al.,
"Ageing in the LHCb Outer Tracker: Phenomenon, culprit and effect of oxygen", Nucl. Instrum. Meth. A617, 202 (2010).
[2] N. Tuning, S. Bachmann, et al.,
"Ageing in the LHCb Outer Tracker: Aromatic hydrocarbons and wire cleaning", Nucl. Instrum. Meth. A656, 45 (2011).
