Development of an ultrathin liquid sheet target for laser ion acceleration at high repetition rates in the kilohertz range

Abstract

A colliding microjet liquid sheet target system was developed, and tested for pairs of round nozzles of 10, 11, and 18µm in diameter. The sheet's position stability was found to be better than a few micrometers. Upon interaction with 50mJ laser pulses, the 18µm jet has a resonance amplitude of 16µm at a repetition rate of 33Hz, while towards 100Hz it converges to 10µm for all nozzles. A white-light interferometric system was developed to measure the liquid sheet thickness in the target chamber both in air and in vacuum, with a measurement range of 182 nm -1µm and an accuracy of ±3%. The overall shape and 3D shape of the sheet follow the Hasson-Peck model in air. In vacuum versus air, the