Measurement of the drift field in the ARGONTUBE LAr TPC with 266~nm   pulsed laser beams
  ARGONTUBE is a liquid argon time projection chamber (LAr TPC) with a drift field generated in-situ by a Greinacher voltage multiplier circuit. We present results on the measurement of the drift-field distribution inside ARGONTUBE using straight ionization tracks generated by an intense UV laser beam. Our analysis is based on a simplified model of the charging of a multi-stage Greinacher circuit to describe the voltages on the field cage rings. 
A. Ereditato, D. Goeldi, S. Janos, I. Kreslo, M.Luethi, C. Rudolf von   Rohr, M. Schenk, T. Strauss, M. S. Weber and M. Zeller
physics.ins-det hep-ex