DE29715915U1 - Device for an open flight diode laser spectrometer - Google Patents

Description

•« ·

Dipl.-Geophys.

Joachim Laudam 2.9.97 / 1

Soorstr. 74

14 050 Berlin

To the

German Patent Office

80 297 Munich

Short description for an open flight DLS in the M-55 Geophysica aircraft

Device for an open flight diode laser spectrometer for extending from the fuselage of the M-55 Geophysica. A utility model for my patent DE 43 09 417 C2 dated 21.7.94 from the German Patent Office in Munich.

The open flight DLS offers the possibility of in-situ measurements of strongly polar gases, short-lived radicals, reservoir and tracer gases in ozone chemistry in the stratosphere, which until now could only be measured simultaneously and continuously with difficulty or not at all (e.g. H ₂ O / NO, NO ₂ , HNO ₃ , ClO, BrO / HCl, HOCl, BrCl, ClONO ₂ / CFC-F12, N ₂ O, CO ₂ , CH ₄ , HF). On the other hand, these measured values are urgently needed for model calculations in order to be able to better predict the global, profound changes in the atmosphere. The flight DLS can take unadulterated and continuous measurements when extended outside the aircraft and can be calibrated when retracted in the aircraft. When retracted, it is also better protected against icing during takeoff and landing and offers no air resistance to reach a maximum altitude of over 20 km. The accommodation in the aircraft fuselage outside the pressurized cabin provides the possibility of a slow temperature adjustment of the flight DLS to below -80 ⁰ C in the ozone hole.

Compared to the drawings in my patent application, filed on 24.3.93, the present design has the following advantages:

1. The mirrors of the multi-reflection cell (Herriott cell) are supported twice on the left and right and are therefore less sensitive to vibrations.

2. This mount also allows for parallel mounting of several Herriott cells, e.g. 3 in the drawing. Since the current state of the art allows up to 4 trace gases to be measured simultaneously per Herriott cell, 3 Herriott cells result in a maximum of 12 trace gases. This is a long-sought requirement for stratospheric ozone research, as can be read in the new book of the European Commission (Luxembourg, 1997) "European Research in the Stratosphere" on page 90 and page 239.

3. Since the supports (3) of the mirror holder (2) are now attached to the side (previously to the rear), the open air flow through the Herriott cell is now also undisturbed at the rear, and the measurement is no longer negatively influenced.

Joachim Laiidam 2.9.97 / 3

Explanations for the drawing of open flight DLS

1 extendable device from the aircraft fuselage outside the pressurized cabin for max. 3 Herrriott cells measuring in parallel and thus simultaneously for up to 12 trace gases

2 Aerodynamically designed mirror mount

3 Aerodynamic carrier

4 Clearance space for boundary layer flow outside the aircraft (approx. 10 cm)

5 Aircraft opening (max. 0 44 cm)

6 containers for diode lasers and optics

6' " (position when retracted)

7 Four slide rails at the corners of the container (6), which are attached to the top and bottom of the aircraft fuselage

8 Spindle for extending the Herriott cells

9 Electric drive motor for the spindle (8)

10 calibration tubes that are simultaneously inserted into the Herriott cells (1) in the retracted state and sealed. Calibrations can then be carried out in the laser beam with zero and test gases in the tubes during the flight in 2 to 3 minutes.

11 Control electronics and computers in the payload compartments A and/or B of the M-55 Geophysica ( ^f- 4-J

Approximate dimensions max. min.

H Length of extendable device

h Length of open Herriott cells

1 => optical absorption path

r => number of reflections t measuring time (integration time)

G Number of trace gases that can be measured simultaneously and continuously

d Diameter of the concave mirrors &eegr; Number of parallel Herriott cells D => Diameter of the aircraft opening

1.80m 1.10m 1.00m 0.30m 80m 25m 80 83 Is 30s 12 4 0 10cm 0 7 cm 3 1 0 44cm 0 17cm

Claims (3)

Joachim Laudam 2.2.98 / 2 Protection claims 1. The device for an extendable open flight diode laser spectrometer is characterized in that it can be extended from the aircraft fuselage with a double bearing of the mirror holder and is aerodynamically designed. The optical axis is perpendicular to the direction of flight and in the free air flow. 2. The device in claim 1 is characterized in that the mirror holder can accommodate several parallel multi-reflection cells (e.g. 3 Herriott cells of approx. 1 m length and with 12 different diode lasers).