  We report the development and first results of an instrument called Low Layer
Scidar (LOLAS) which is aimed at the measurement of optical-turbulence profiles
in the atmospheric boundary layer with high altitude-resolution. The method is
based on the Generalized Scidar (GS) concept, but unlike the GS instruments
which need a 1- m or larger telescope, LOLAS is implemented on a dedicated
40-cm telescope, making it an independent instrument. The system is designed
for widely separated double-star targets, which enables the high
altitude-resolution. Using a 20000-separation double- star, we have obtained
turbulence profiles with unprecedented 12-m resolution. The system incorporates
necessary novel algorithms for autoguiding, autofocus and image stabilisation.
The results presented here were obtained at Mauna Kea Observatory. They show
LOLAS capabilities but cannot be considered as representative of the site. A
forthcoming paper will be devoted to the site characterisation. The instrument
was built as part of the Ground Layer Turbulence Monitoring Campaign on Mauna
Kea for Gemini Observatory.
