ExoMars UV Laser diode thermal vacuum test

Alex Rousseau

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.

Test equipment

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.

Laser diode installation in TV chamber

Test profile

• Cold non operational T: -150°C• Hot non operational T: +50°C• Hot operational T: +25°C• Cold operational T: ≥60°C

Test results – thermal profile

Test results – UV Laser diode output vs temperature

Test results – UV Laser diode output at test points

Test results – UV Laser diode temperature transition rates