ABSTRACT Accreting supermassive black holes (SMBHs), also known as active galactic nuclei (AGN), are generally surrounded by large amounts of gas and dust. This surrounding material reprocesses the primary X-ray emission produced close to SMBH gives rise several components in broadband spectra AGN, including a power-law possibly associated with Thomson-scattered radiation. In this work, we stud...

This article deals with the enhancement of accuracy in CT by just-in-time correction of artefacts (beam hardening, scattered radiation) caused by the interaction of X-rays with matter. The so called EAR method needs for simulation a registration of the object. Therefore the article presents two different registration concepts.

The polystyrene based scintillator SCSN38, pure polystyrene and pure polymethyl-methacrylate have been irradiated with a beam of fast neutrons and with reactor neutrons. The radiation induced permanent optical absorption coeecients after total annealing in air are compared with data for irradiations. The strong diierences might be due to the high LET of the recoil protons elastically scattered ...

I propose to use as a window the dark core of an optical vortex to examine a weak background signal hidden in the glare of a bright coherent source. Applications such as the detection of an astronomical object, forward-scattered radiation, and incoherent light are described whereby signal enhancements of at least 7 orders of magnitude may be achieved.