The Barcelona Raman LIDAR for the CTAO-North

The Barcelona Raman LIDAR (BRL) project is developing a LIDAR for online aerosol characterization of the northern site of the Cherenkov Telescope Array Observatory (CTAO-N). Such telescopes observe Cherenkov light emitted throughout the lower stratosphere and the troposphere, the aerosol and cloud profiles of which must be continuously monitored. Requirements include the ability to take aerosol extinction profiles to distances of more than 30 km and time scales of less than a minute after pointing to any target in the sky down to 25° altitude. The BRL consists of a 1.8 m parabolic mirror and a pulsed Nd-YAG laser. A liquid light guide collects the light at the focal plane and transports it to an in-house built polychromator unit. A prototype of the device was brought to the site and tested, the experience of which has resulted in a few improvements to the system.