National Center for Atmospheric Research
ATD... Airborne Excimer UV-DIAL

Description

The optical design of the lidar is based on a krypton fluoride laser with subsequeent Raman shifting in hydrogen and in deuterium. The output of the laser is split into two Raman cells in a ratio of approcimately 33% to 67% respectively. The output of the Raman cells that are used in this system are at 277 nm, 292 nm, 313 nm, 319 nm, and 360 nm with pulse energies ranging from 5 mJ to 15 mJ. The beams from each cell are collimated and transmitted off-axis of the receiving telescope. The collected light is separated into five wavelength channels by a grating spectrograph and detected by photomultiplier tubes that are mounted at the exit of the specrograph. This system is unique in its numer of wavelenghts available. Because of this, it is possible to use different combinations of these wavelenghts to calcuate the ozone concentration and aerosol backscatter profiles as well as check that they are all consistent with each other.

The UV-DIAL has been specifically designed for airborne operation and profiling of the lower troposphere, typically flown on a small cargo type aircraft and used in a nadir looking configuration.

System Parameters

Laser Type and Wavelength Krypton fluoride, 248 nm
Transmit Wavelengths after Raman shifting 277, 292, 313, 319, 360 nm
Transmit Energy 5 - 15 mJ per pulse per wavelength
Beam Divergence 0.5 mrad (full angle)
Pulse Repetition Frequency 20 Hz
Telescope Type and Diameter Newtonian, 0.5 m
Telescope Field of View 1.5 mrad (full angle)
Detector Type Photomultiplier tubes
Digitizer Resolution on all Channels 12 bits
Digitizer Sample Rates 5 MHz all channels except 360 nm at 10 MHz
Data Storage 8 mm magnetic tape
Real Time CPU Micro VAX II
Data Acquisition DSP Technology 2012 digitizers in a CAMAC crate
Lidar Size 42" wide, 108" long, 50" tall
System Weight 2200 lbs including computer and operators
Power Requirement 150 amps of 28 VDC (4200 watts)

The information was extracted from Airborne Excimer UV-Dial Results from the 1995 Southern Oxidant Study by Mayer et al. 1996. For more information, contact Mike Hardesty at hardesty@ucar.edu

Brigitte Baeuerle <baeuerle@ucar.edu>
Last modified: Thu Sep 5 14:11:45 1996