Sep 3 – 8, 2017
The Open University, Milton Keynes, UK.
Europe/London timezone

Simulated spectrum of the OGRE X-ray camera system

Sep 7, 2017, 12:40 PM
1h 50m
Hub Theatre (OU)

Hub Theatre (OU)

The Open University, Walton Hall, Milton Keynes, MK7 6AA


Matthew Lewis (The Open University)


The X-ray astronomical telescopes in use today, such as Chandra and XMM Newton, use X-ray grating spectrometers to probe the high energy physics of the Universe. These instruments typically use reflective optics for focussing onto gratings that disperse incident X-rays across a detector, often a Charge-Coupled Device (CCD). The X-ray energy is determined from the position that it was detected on the CCD. Improved technology for the next generation of X-ray grating spectrometers has been developed and will be tested on a sounding rocket experiment known as the Off-plane Grating Rocket Experiment (OGRE).
OGRE aims to capture the most accurate soft X-ray spectrum of Capella, a well-known astronomical X-ray source, during an observation period of approximately 5 minutes whilst proving the performance and suitability of three key components. These three components consist of a telescope made from Iridium coated silicon mirrors, gold coated silicon X-ray diffraction gratings and a camera that comprises of four Electron-Multiplying (EM)-CCDs that will be arranged to observe the soft X-rays dispersed by the gratings.

EM-CCDs have an architecture similar to standard CCDs, with the addition of an EM gain register where the electron signal is amplified so that the effective signal-to-noise ratio of the imager is improved. On OGRE, this improved detector performance allows for easier identification of low energy X-rays and fast readouts due to the amplified signal charge making readout noise almost negligible.

A simulation that applies the OGRE instrument performance to the Capella soft X-ray spectrum has been developed that allows the distribution of X-rays onto the EM-CCDs to be predicted. The pixelated X-ray events will be simulated according to the detector architecture to demonstrate the order separation capabilities of the instrument and produce sample images expected from in-flight operation on which X-ray event identification algorithms can be developed.

Primary author

Matthew Lewis (The Open University)


Matthew Soman (Open University) Prof. Andrew Holland (The Open University) Mr James Tutt (Pennsylvania State University) Mr Randall McEntaffer (Pennsylvania State University) Mr Ted Schultz (Pennsylvania State University) Mrs Karen Holland (XCAM Limited)

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