The INTEGRAL X-ray monitor, JEM-X, (toghther with the two gamma ray instruments, SPI and IBIS) provides simultaneous imaging with arcminute angular resolution in the 3-35 KeV band. The good angular resolution and low energy response of Jem-X plays an important role in the detection and identification of gamma ray sources as well as in the analysis and scintific interpretation of the combined X-ray and gamma ray data. Jem-X is a coded aperture X-ray telescope consisting of two identical detectors. Each detector has a sensitive area of 500 cm^2, and views the sky through its own coded aperture mask. The coded mask are located 3.4 m above the detecor windows. The detector field of view is constrained by X-ray collimator
