Scintillation yields in liquid argon are found to increase in the presence of external electric fields (≤6 kV/cm) by 4%, 9%, 12%, and 15% for He ions with energies of 5.5, 10, 15, and 20 MeV, respectively. Comparative studies with α particles of 5.305 MeV found very little effect on the magnitude of the scintillation increase with orientation of the incident particle. The increase in scintillation was not associated with an observable decrease in charge collected and it may be due to a decrease of quenching in the track core of the incident particle.

• Received 13 April 1992

DOI:https://doi.org/10.1103/PhysRevB.46.540