High Speed, High Throughput Two Dimensional Direct Electron Detector Based on the Concept of pnCCDs

Abstract

Two dimensional direct detection electron imaging solid state sensor systems, subject to intense radiation, suffer from charge overflow to neighbouring pixels. This not only affects the dynamic range and linearity, but also the position precision of e.g. the electron impinging on the detector. Various techniques have been proposed to overcome the problem of charge overflowing the pixels. Several sensors are able to cope with up to a few million signal charges per pixel. In many scientific applications, e.g. in free electron laser science and electron detection in TEMs, this is by far not sufficient. We have developed a technique to handle 1 billion signal charges per pixel without charge spilling over to neighbouring pixel within one readout frame of typically 1 ms. The quality of the point spread function remains unchanged but amplitude information may be degraded. We call this mode of operation: controlled charge extraction (CE) mode.