Sites

Medellin

Sites.Medellin History

Hide minor edits - Show changes to output

September 11, 2012, at 10:54 PM by 143.107.134.147 -
Added lines 1-8:
(:Title Medellin:)

The lidar system, operated in the city of Medellín, (tropical valley situated at the Andes in South America (6° 13´ 55" N, 75° 34´ 05" W, 1538 m asl), has a coaxial configuration with two wavelengths backscatter system pointing vertically to the zenith. The light source is a pulsed Nd:YAG laser, donated by the IFAC, Italy, operating, by means of frequency doubling using KD*P crystals, are obtained two wavelengths simultaneously (1,064 and 532 nm). The energy per pulse is 400 mJ at 1,064 nm and 200 mJ at 532 nm, respectively. The emitted laser beam to the atmosphere, it has been expanded from 6 to 12 mm of diameter, reducing the divergence to 0.3 mrad. The emitter system is a modified Newtonian telescope of 1.2 m focal length. The light backscattered from the close-range altitudes (0.2-3.0 km) are received by a 20.32 cm diameter Newtonian telescope. Currently, in virtue to one narrow-band interference filter (1.0 nm FWHM at 532 nm) the system operates with singular lidar signal to 532 nm, blocking the background skylight during daytime operation. The lidar signal in this wavelength is detected using a H6780 photo-multiplier module (Hamamatsu), and the signal acquisition in an analog mode is made with a one-channel Digitizing Oscilloscope, which acts both as a 11-bit analog-to-digital converter (ADC) and as a waveform recorder.

A complete overlap between the laser beam and the telescope's field-of-view is obtained at a range above of 200 m, as has been estimated by geometrical form factor calculations performed according to Dho, Park and Kong.

*Coming soon will be operated remotely.
*The system is covered (rain proof).