We have utilized rf glow discharge hydrogenated amorphous silicon (a‐Si:H) to build detectors in sandwich geometry with response times in the ps region. Analyzing the shape of the pulses recorded with a sampling head, carrier relaxation times and drift times were obtained. A transition from relaxation time limited to drift time limited response was observed by increasing the bias voltage. Carrier relaxation times and drift mobilities were determined as 460 ps and 0.2 cm2/V s, respectively, the shortest drift time limited response was below 80 ps.