Temporal Resolution of X-ray Detector for Pulsar Navigation

Pulsar navigation is a promising new technique for space exploration because of its autonomous and deep space capability. Since the baseline of pulsar navigation approach is to observe the X rays (0.2 similar to 20keV) emitted from pulsars, a compact high temporal resolution X-ray detector is needed. In this paper an micro-channel plate(MCP) photon counting detector sensitive to X-rays is proposed. The detection system consists of a CsI photocathode, a 50mm diameter micro-channel plate (MCP) stack, a collection anode, a preamplifier, a constant fraction discriminator(CFD) and data acquisition(DAQ). The incident X-rays photons are absorbed by CsI and converted to photoelectrons, the electrons are multiplied by MCP and collected by the anode. Anode output signal is a fast pulse which need to be amplified by preamplifier and then fed to CFD circuit and DAQ for a precise timing. The total temporal resolution(Delta T) of the entire detection system could be determined by Delta t(D), the intrinsic temporal resolution of cathode-MCP-anode, and Delta t(E) the resolution of electronic system including preamplifier and CFD. The resolution of the detection system is tested to be 18.4ns in experiment.