The effects of cryocooler microphonics, EMI and temperature variations on bolometric detectors Original Research Article

The use of mechanical coolers for space-based infrared telescopes is becoming a reality with the development of the Planck spacecraft, which will obtain full sky maps of the temperature anisotropy and polarisation of the cosmic microwave background (CMB). The High Frequency Instrument is one of two instruments aboard Planck and will use 48 bolometric detectors operating at 0.1 K. We summarise the performance of the RAL 4 K Joule–Thomson (J–T) system which will precool these detectors, and describe integration aspects of the sensitive bolometric detectors with cryocoolers at system level, in particular the effects of cryocooler vibration, EMI and thermal fluctuations. Full understanding of these systematic sources of noise is critical to enable the microkelvin level scientific signals to be cleanly extracted from the raw data.