Planar Detectors

A planar detector is usually a disk with the electrical contacts covering all or a part of the flat surfaces. The ratio of the capacitance to volume is poor for planars compared with coaxial detectors. However, HPGe planar detectors are rugged and have high efficiency in the lower energy ranges. The capacitance of PGT n-type semi-planar germanium detectors, with a wrap-around P+ contact and a small center N+ contact, is much less than that of a true planar of similar size. This results in lower noise and better resolution than achieved by any other detector geometry at energies of 3 keV to 1 MeV. Lithium-drifted silicon, Si(Li), planar detectors are used mainly for X-ray spectroscopy. They are suitable for energies from ~100 eV to 60 keV.

Planar Detectors

Planar and Semi-Planar HPGe Detectors

X-ray Detectors