In this paper, we apply the direct demodulation technique to analyse simulated data of a rotating modulation collimator telescope for the first time. The direct demodulation method has already been applied successfully to image analysis for various kinds of data in high energy-astronomy, e.g. for data of -ray imaging telescope COS-B (Li & Wu 1990), for scan observation data of slat collimator telescopes: the scan imaging for CygX-1 by the balloon-borne hard X-ray collimated telescope HAPI-4 (Lu et al. 1995) and for EXOSAT-ME data of the galactic plane survey (Lu et al. 1996), for data from the Compton scatter telescope COMPTEL/CGRO (Zhang et al. 1996). Simulation results show that the direct demodulation technique can significantly improve imaging quality of the coded mask aperture telescope (Li 1995). As seen in this paper, the application of this method to telescopes based on a rotating modulation collimator is also feasible. Images from RMC with the direct demodulation technique have much higher angular resolution than those with cross-correlation analysis. The direct demodulation images have almost no sidelobes and can represent both discrete and extended structures. After considering the improved performance with the direct demodulation method, the RMC technique might be more competitive for future imaging instrumentation in high-energy astronomy.
The authors thank Dr. F.J. Lu and Y.X. Feng for helpful discussions. This work was supported by the National Natural Science Foundation of China.