  High repetition rate gas targets constitute an essential component in intense
laser matter interaction studies. The technology becomes challenging as the
repetition rate approaches kHz regime. In this regime, cantilever based gas
valves are employed, which can open and close in tens of microseconds,
resulting in a unique kind of gas characteristics in both spatial and temporal
domain. Here we characterize piezo cantilever based kHz pulsed gas valves in
the low density regime, where it provides sufficient peak gas density for High
Harmonic Generation while releasing significantly less amount of gas reducing
the vacuum load within the interaction chamber, suitable for high vacuum
applications. In order to obtain reliable information of the gas density in the
target jet space-time resolved characterization is performed. The gas jet
system is validated by conducting interferometric gas density estimations and
high harmonic generation measurements at the Extreme Light Infrastructure
Attosecond Light Pulse Source (ELI ALPS) facility. Our results demonstrate that
while employing such targets for optimal high harmonic generation, the high
intensity interaction should be confined to a suitable time window, after the
cantilever opening. The measured gas density evolution correlates well with the
integrated high harmonic flux and state of the art 3D simulation results,
establishing the importance of such metrology.
