Detector arrays:

• six arrays of photoconductive detectors used in SWS:
  ­ 4 arrays with 12 detectors each in the grating sections
  ­ 2 arrays with 2 detectors each in the Fabry-Pérot section

• arrays arranged in the direction of dispersion
• they define the SWS band structure (band 1 - 6)
• cover the SWS spectral range 2.38 - 45.2 µm

• detector size determines FOV perpendicular to dispersion
• relative detector size:   d _LW ~ 1.5 d _SW   and   d _FP ~ 2 d _SW

• heaters are provided for all detector arrays (FPU at ~ 2 K)
• Si:Sb array is heated to an optimum temperature of 10 K
• Ge:Be array is connected to a cryogenic 2 K heat sink

Read-out electronics:

• cold read-out electronics:
  ­ integrating pre-amplifiers with non-destructive read-out,
    employing heated JFET's
  ­ read-out at a rate of 24 Hz
  ­ signal of all 52 detectors
  ­ part of Focal Plane Unit (FPU)

• warm amplifier electronics:
  ­ 52 identical main amplifiers
  ­ multiplexer and ADC circuitry
  ­ outside cryo-harness

• 3 reset intervals: tr = 1 and 2 sec, also 4 sec for band 1
  ­ determined from observer's input
  ­ longer reset intervals for faint sources
  ­ reset pulse discharges capacitor (basically short-circuited)

• 3 gain settings: 1x, 4x or 16x
  ­ determined from observer's input
  ­ no saturation, if source flux density < 50,000 - 100,000 Jy
    and flux density estimate accurate to a factor of four

Instrumental/environmental effects:

• pointing jitter
• detector signal jumps
• glitches / glitch tails
• memory effects (esp. band 2, 4, 5 and 6)
• fringes (esp. band 2C and 3)