(1) University of Glasgow, Kelvin Building, Glasgow G12 8QQ, Scotland.
(2) Department of Medical Physics + Bioengineering, UCL, UK
(3) Instrumentation Department, STFC (RAL), UK
Despite the continuing success of the charge couple device (CCD), the last 2 decades have seen APS devices become increasingly popular in their use as portable, low cost imagers. Despite suffering from higher readout noise than the CCD, APS have a number of advantages. These include lower power consumption, lower cost, random access and selective readout. The possibility to incorporate on-chip functionality such as analogue-to-digital conversion (ADC), timing logic for thresholding and gain adjustment is driving an increased interest in these devices from the scientific community. In 2004, A UK consortium (MI3) was formed under an RC-UK Basic Technology Programme to develop CMOS active pixel sensors for a broad range of scientific applications including space science, particle physics and medical imaging. During the programme 6 APS' were designed, fabricated and tested. Highlights from the project include: the LAS (Large Area Sensor), a novel stitched sensor designed for use in medical imaging; eLeNA (Low Noise), a test structure which develops a range of low noise pixels and OPIC (On Pixel Intelligent CMOS), a test structure designed for in-pixel intelligence including sparse read-out, ADC and storage in each pixel and thresholding.
11th International Workshop on Radiation Imaging Detectors
28 June - 2 July 2009, Prague, Czech Republic