JEM-X: Joint European X-ray monitor

JEM-X is the X-ray monitor for INTEGRAL. It is being built by a large Europ ean consortium led by the Danish Space Research Institute. It consists of t wo identical, independent coded mask X-ray telescopes with an energy span f rom 3 keV to 60 keV. Each system has a microstrip gas detector and a mask w ith a 25% transparent hexagonal uniformly redundant pattern based on a bi-q uadratic residue set situated 3.4 m above the detector. The fully illuminat ed field-of-view is circular and 4.8 degrees across. The mechanical propert ies and source detection sensitivities are reviewed.