We measure electron-hole recombination rate in low-temperature pure silicon using the photo-MuSR technique. The previous works have measured the recombination rate down to -30 C, and there is no experiment below this temperature. The low T experiments are important not only for the industrial applications but also for the semiconductor physics. In low-T pure silicon the Auger recombination becomes the predominant process. Little is known about how the Auger recombination depends on the temperature in the low-T regime. We have recently observed the photoinduced electrons in Si depolarising the muon asymmetry, which is described by the cyclic charge exchange process. Therefore the muon spin relaxation rate can be utilised to measure the photoinduced electron density. By making a delay between the muon and light pulse we can observe its dynamics.