EG&G
EG&G ORTEC 934 CFD Quad Constant Fraction Discriminator
Using the HBN 0.5microns version has made a noticeable difference in air quality.
EG&G 1412XR Detector Head w/ ORIEL 11026 & 11824 & 13870 Stand
You will find that the ULTRA-2 runs quietly, which is a big plus in a busy shop.