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10.12.2018 10:41

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Криогенный радиометр CryoRad II



The CryoRad II is the first universal cryogenic electrical substitution radiometer, designed for convenient detector calibrations with both laser, lamp or monochromator illumination. It’s novel cavity design enables use with beams as fast as f/8 without changing or moving the receiver. Its fast cavity response removes background drifts and provides noise thresholds below 2 nW, even with an f/8 entrance aperture and viewing an ambient-temperature window. The highest accuracy (0.005 %) is achieved in laser beam measurements with a Brewster-angled window. In monochromator measurements, the sensitivity and accuracy are a factor 5 – 10 better than achieved with room temperature ESR’s. The CryoRad II is now in use at metro-logy laboratories throughout the world, for a wide range of photo-detector calibrations. CryoRad versions available for laser, monochromatic, synchrotron, or low background IR applications.


  • Accepts laser, lamp or monochromator sources – no need to change receivers
  • Absolute accuracy 0.005 % with laser illumination and ~0.01 % with incoherent sources
  • Active receiver response increases measurement speed and helps to remove drift in lamp & monochromator inputs
  • Low-noise AC-bridges for high signal to noise operation
  • Germanium resistance thermometry (GRT) for superior sensitivity
  • ASCII command control via 100 MBaud Ethernet interface
  • Modular electronics for easy in-house calibration


Spectral Range 0.25 – 50 µm
Receiver Thermal Response Time (1/e) (1/e) < 8 seconds
Servo Settling Time (to 0.01 % of signal) 40 seconds
Receiver Responsivity 2 ±0.25 K/mW
Dynamic Range to 1 mW
Noise (rms) < 2 nW (varies with operating power)
Absolute Accuracy  < 0.005 %
Cryostat Dimensions 27 cm (D) × 55 cm (H)
Cavity absorptance > 0.9999 (at 632.8 nm)
LHe hold time > 72 hrs

* nominal values — modifications upon request to meet other requirements