Two fast photodiodes for use in pulse radiolysis

In this paper we describe the characteristics of two photodiodes which make them very useful for pulse radiolysis studies. These detectors are the EG & G SHS-100 Si photodiode and the Barnes room temperature A-100 InAs photodiode. The former has a linear output up to at least 6·5 mA, has a 0–98% response time ≌ 15 ns and is distinguished from Si photodiodes previously described by having no detectable slow component to its response. The 0–98% response time of the A-100 photodiode and the circuit developed for it is about 60 ns, and it also shows no detectable slow response component. The output of the A-100 is linear up to at least 2 mA, and we have used it for absorption measurements between 450 and 3200 nm.