Trench-MWPC 3He Detector for XtremeD Neutron Diffraction Instrument

The XtremeD instrument will be dedicated to neutron diffraction by powder and crystal samples under extreme conditions of temperature, pressure, magnetic field and chemical environment. In order to fulfil the requirements of the instrument, a Trench Multi-Wire-Proportional-Chamber (Trench-MWPC) was developed with a wide angular coverage (130° horizontally and 24° vertically), and an angular resolution of 0.15° horizontally and 0.19° vertically. Nine detector modules have been assembled and mounted inside a single pressure vessel. The technical challenges and solutions regarding the different parts of the detector are discussed and preliminary experimental results obtained during the characterization of the detector are presented.