A streaked pyrometer has been designed to measure the temperature of ≈100 µm diameter heated
targets in the warm dense matter region. The diagnostic has picosecond time resolution. Spatial
resolution is limited by the streak camera to 4 µm in one dimension; the imaging system has
superior resolution of 1 µm. High light collection efficiency means that the diagnostic can transmit
a measurable quantity of thermal emission at temperatures as low as 1 eV to the detector. This is
achieved through the use of an f/1.4 objective, and a minimum number of reflecting and refracting
surfaces to relay the image over 8 m with no vignetting over a 0.4 mm field of view with
12.5× magnification. All the system optics are highly corrected, to allow imaging with minimal
aberrations over a broad spectral range. The detector is a highly sensitive Axis Photonique streak
camera with a P820PSU streak tube. For the first time, two of these cameras have been absolutely
calibrated at 1 ns and 2 ns sweep speeds under full operational conditions and over 8 spectral bands
between 425 nm and 650 nm using a high-stability picosecond white light source. Over this range the
cameras had a response which varied between 47 ± 8 and 14 ± 4 photons/count. The calibration of
the optical imaging system makes absolute temperature measurements possible. Color temperature
measurements are also possible due to the wide spectral range over which the system is calibrated;
two different spectral bands can be imaged onto different parts of the photocathode of the same streak
camera.