  We describe an optical near shot-noise limited time-resolved circular
dichroism (TRCD) pump-probe spectrometer capable of reliably measuring {\mu}deg
circular dichroism signal with nanosecond time resolution. Such sensitivity is
achieved through a modification of existing TRCD designs and introduction of a
new data processing protocol that eliminates approximations that have caused
substantial nonlinearities in past measurements and allows the measurement of
absorption and CD transients simultaneously with a single pump pulse. The
exceptional signal-to-noise ratio of the described setup makes TRCD technique
applicable to a large range of non-biological and biological systems. The
spectrometer was used to record, for the first time, weak TRCD kinetics
associated with triplet state energy transfer in the photosynthetic
Fenna-Matthews-Olson antenna pigment-protein complex.
