LESIA - Observatoire de Paris

OBAMA test facility

Monday 7 January 2019, by Jérôme Parisot

The OBAMA test facility offers the next functions:

  • Simulate and control the environment conditions of an IR detector, mainly regarding vacuum and thermal conditions and its optics.
  • Allow its calibration.

OBAMA is located in a 40m2 cleanroom (TITAN cleanroom, class 1000 or ISO 6 under flux) equipped with a dissipative floor.

OBAMA bench
OBAMA bench

Overview of the cleanroom

OBAMA (Optical Bench for Analysis of MAtrix) has been developed for the calibration of the IR detector of the VIHI instrument (BepiColombo mission). The installation has been conceptualized with the idea of being used for other future projects, so with a certain degree of flexibility. The setup consists of:

  • A vertical cylindrical vacuum chamber DN250, height 416 mm.
  • A pump system (primary + secondary) including:
    • A primary diaphragm pump (dry, oil-free)
    • A turbomolecular pump DN63 ISO-K
  • A cryogenerator RICOR K535 with a cooling power of 14W @120K
  • A window Ø 3 inches in CaF2
  • Hermetic mechanical passages: rotation + translation
  • Hermetic mechanical passages: SubD-44HD, SubD-37, SubD-9
  • An optical bench (1200x2400 mm2) carrying optical stimuli (integrating sphere, monochromator, halogen source…).

3D view of the assembly
3D view of the assembly

The OBAMA bench is entirely automatized by the software LabVIEW. The command PC allows to pilot:

  • The pumping + pressure reading
  • The cryogenerator
  • The reading of the temperature probes
  • The movement of an obturator (stepper motor)
  • The movement of a blade with steps of 2µm (DC motor)
  • The acquisition of the reference detectors (on the integrating sphere)
  • The monochromator
  • The power supplies (LEDs + heaters)
  • The acquisition of the detector (integration time & polarization)
  • The acquisition of the temperature + humidity of the cleanroom
  • The recording of all the data to .fits files
  • The management of all the users (login, access rights, history …)

The calibration consists of determining the characteristic magnitudes of the detector by exploring the results of the following measurements :

  • Response as a function of the load ;
  • Dark current ;
  • Read-out noise ;
  • Response as a function of the photon flux ;
  • Flat fields as a function of the wavelength;
  • Remanence & saturation.

Vacuum chamber opened
Vacuum chamber opened

View from the entry

Vacuum chamber opened
Vacuum chamber opened

View from the top