Organic semiconductors have been of major interest in recent years. Amplified by the transition from fundamental physics to new commercial products and technologies, this new class of materials has the potential to replace current technologies based on conventional electronics. We have recently performed a longitudinal field repolarisation measurement of tetracene polycrystals, where a crossover from band to thermally assisted transport has been observed. This phenomena, first predicted in 1959, has not to our knowledge been experimentally verified before. Muons are able to measure it due to the local nature of the probe. We wish to measure the electric field dependence to the crossover temperature.