Multi-wavelength scanning Raman lidar simulations for the Cherenkov telescope array observatory

Abstract

This paper discusses the multi-wavelength scanning Raman lidar being built at Lidar Division, CEILAP (CITEDEF-CONICET) in the frame of the Argentinean CTA (Cherenkov Telescope Array) collaboration. CTA is an initiative to build the next generation of ground-based instruments to collect very high energy gamma-ray radiation (greater than a few tens of GeV). The atmospheric conditions are of major interest to CTA, and lidars are requested to acquire atmospheric profiles fast, accurately and in the line of sight of the event. Due to the expected low aerosol optical depth of the future site, the short observation period as well as the extension of the observation, an enhanced collection area is required. Based on this constraints, and energy laser pulse, a backscatter lidar signal simulation was performed to estimate the main characteristics of the system. To derive these features, a SNR (signal-to-noise ratio) was also simulated to derive the total number of mirrors to achieve a good quality signal over the whole tropopause. Raman capabilities were added in the UV and VIS wavelengths to retrieve the spectral characteristics of the aerosol extinction and the water vapor profile. The results of the simulation, and the main characteristics derived are shown.

En este trabajo se describe la simulación del lidar Raman multiángulo que se está desarrollando en la división lidar del CEILAP (CITEDEF-CONICET), en el marco de la colaboración argentina del observatorio CTA (Cherenkov Telescope Array). Este Observatorio es una iniciativa para construir una nueva generación de instrumentos para detectar radiación gamma de muy altas energías (superior a 10 GeV). En base a restricciones de construcción y de parámetros atmosféricos, se realizó la simulación de la relación S/R (señal/ruido) para obtener el área total de colección del sistema lidar. Este sistema está planeado para medir señales Raman de nitrógeno y vapor de agua provenientes de las líneas de 355 nm y 532 nm.