Monte Carlo Method is used to simulate a double layer gadolinium-amorphous silicon thermal neutron detector. The detector fabricated in pixel array configuration has various applications including neutron imaging. According to the simulation results, a detector consisting of a gadolinium (Gd) film with thickness of 2-4 ~m, sandwiched properly with two layers of sufficiently thick (-30 ?µm) hydrogenated amorphous silicon (a-Si:H) diodes would have the optimum characteristics. At a threshold setting of ~7000 electrons, the detectors would have efficiency of about 42%. The expected average signal size is about 12000 electrons, which is well above the noise. These neutron detectors have very low gamma sensitivity and are very well suited to real time neutron imaging applications. A
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