1. ExoMars UV Laser diode thermal vacuum test Alex Rousseau

2. Test setup Used ExoMars CCD test vacuum chamber. LN2 cooling with heaters backing off LN2. Fully automated thermal control system. Rotary vacuum pumped chamber (5x10 -3 mBar). Photodiode fixed to chamber viewport to measure UV laser diode output. Temperatures and photodiode output logged at 1 minute intervals.

3. Test equipment

4. Test setup (Cont.) UV laser diode assembly installed between two cold fingers and PID closed control loop temperature sensor installed on the laser diode mount (as close as possible to diode). Two temperature logging sensor installed on laser diode mount. Bench PSU connected through vacuum feed through for PCB V & I supply.

5. Laser diode installation in TV chamber

6. Test profile Cold non operational T: -150°C Hot non operational T: +50°C Hot operational T: +25°C Cold operational T: ≥60°C

7. Test results – thermal profile

8. Test results – UV Laser diode output vs temperature

9. Test results – UV Laser diode output at test points

10. Test results – UV Laser diode temperature transition rates