Search

In a recent paper, it was described how semi-insulating (SI) liquid encapsulated Czochralski (LEC) gallium arsenide particle detectors made by Alenia SpA have been tested and found to be understandable in terms of one function: the local charge collection efficiency. We have now measured, always within the context of the RD8 experiment, the local charge collection efficiency for these diodes using a technique called OBIC (optical beam induced current) and derived the active region width ( W ) as a function of bias in a range of values lower than those obtainable with particles. Using data both from OBIC and from the previous paper, W is found to behave approximately linearly as a function of bias larger than about 50 V. Below this value, W follows a square root law as a function of bias.

Gallium arsenide particle detectors made by Alenia SpA have been tested within the context of the RD-8 project and found to have a high charge-collection efficiency (75%). We have analysed the data and found the overall behaviour of these detectors to be coherent and understandable in terms of one function: the local charge-collection efficiency. Two ways have been used to measure the width of the active region and the increase of such a width as a function of bias is found not to be consistent with a simple square-root law.