Objective
PROJECT MTR00085 PROJECT DEFINITION Silicon photodiodes have replaced other types of photodetectors such as photocells in a wide range of optical radiation measurements. They possess many qualities which make them ideally suited for many applications (high quantum efficiency over a wide range of wavelength from 200 nm to over 1000 nm), uniform response over their sensitive area and very good linearity. For accurate work there remain difficulties regarding stability. As the demand for calibration of photodiodes as transfer standards is increasing considerably, it was the objective of this project to share the work of evaluating in well defined conditions the stability of a number of the best photodiodes from various manufacturers. RESULTS Devices manufactured by 5 different companies (Centronic, UK, model OSD100-S - AEG, D, model BPW35 - UDT, USA, model PIN-10DPSB-EG & G, USA, model UV444BQ - Hamamatsu, Japan, model S1227-101OBQ) have been tested over a period of five years. All these photodiodes met the following criteria :
- photovoltaic (unbiased) type
- spectral response ranging from 200 to 1000 nm
- commercial availability with active area of 100 mm2 The data base consisted of 4000 results, obtained by the 4 participating laboratories testing 100 devices, 10 times each. The Centronic and Hamamatsu devices have been identified as extremely stable (change in response 1%), and well suited to act as transfer standards.