Spectrophotometric system employing 110m and 30m long multipass cells

The spectrophotometric system is intended for:
  • absolute measurements of absorption coefficients of the atmosphere and its gaseous constituents separately with the sensitivity up to 10-8cm-1;
  • investigation of continuum absorption at long paths imitating real atmospheric paths at pressure, temperature, and humidity variations;
  • investigation of the dynamics of the radiation from any cw or pulsed lasers operating in the IR, visible, and UV regions at long paths in air and molecular gases;
  • calibration of laser spectrometers of other types and local and remote gas analyzers.

This system can be used for solution of principal problems on atmospheric spectroscopy and propagation of laser radiation through the atmosphere.

Additional information is available on request: yupon@iao.ru.

Specifications of the system

Parameters of multipass gas cells

.
Spectroscopic cell 
length, m 30
diameter, m 1.1
pressure, mm Hg 5 10-5 - 103
temperature, K 288 - 350
Atmospheric cell 
length, m110
diameter, m 0.7
pressure, mm Hg 5 10-4 - 103
temperature, K 288 - 330

Parameters of lasers

Alexandrite laser 
tuning range, nm 720 - 780
band width, cm-15 10-3
pulse repetition frequency, Hz < 10
pulse duration, ns 180
pulse energy, J > 10-3
YAG:Nd laser 
wavelength, nm 1064
band width, cm-1 < 0.05
pulse repetition frequency, Hz < 50
pulse duration, ns2 - 2.5
divergencediffraction-limited
pulse energy, J > 1
Nd-glass laser 
tuning range, nm 1.045 - 1.065
band width, cm-15 10-3
pulse duration, s 6 10-8
pulse energy, J0.2
YAG:ТmСrНо laser 
wavelength, nm 2080
band width, cm-1< 0.01
pulse repetition frequency, Hz < 10
pulse duration in free lasing mode, s< 4 10-4
pulse duration in the Q-switching mode, s5 10-8
energy, J0.3
YAG:Er laser3Y3Al5O12 
wavelength, nm3000
band width (averaged), cm-1< 8
pulse repetition frequency, Hz< 50
pulse energy, J< 1
tuning range, nm 10

Parameters of the recording system

ParameterValie
error in determination of line positions, cm-1< 5 10-3
error in measurement of gas transmittance 0.1 - 1
error in pressure, mm Hg< 0.1
threshold sensitivity, cm-110-8