Andrew Holland (The Centre for Electronic Imaging, Open University and XCAM Ltd, UK)

Title : Development of High Performance Silicon X-ray Photon-Counting with Spectroscopy Detectors for Space and Synchrotron Science using CCD and CMOS Technology

In the late 1980's and early 1990's CCD technology was being developed for imaging X-ray spectroscopy for space telescopes, including ESAs XMM and NASAs Chandra observatories. In Europe, the MOS CCD developments were conducted with what is now Teledyne e2v UK (formerly EEV and e2v Technologies). High purity epitaxial and float zone silicon were explored to increase the high energy detection QE, whilst a variety of techniques; thin electrode, open electrode and back-illumination, were explored to increase the soft X-ray QE. These developments will be discussed which led to the creation of high performance focal plane arrays with "fano-limited" energy resolution. The space environment is harsh (and inaccessible) providing damage by space radiation and even micrometeorites. The performance of the XMM EPIC MOS cameras will be reviewed over their 25 years of operation in space. The CCD technologies developed have found many applications in other terrestrial and space applications, particularly in synchrotron research, and results of camera developments for FELs and RIXS will be covered. However, the detector technology has more-recently been moving toward CMOS image sensors. We are now developing advanced CMOS image sensors for the ESA Theseus mission concept which is (currently) one of 3 candidates for ESAs M7 opportunity. Here we are adapting many of the techniques applied to CCDs some decades earlier toward the development of new large area, high frame rate direct detection X-ray sensors, whilst retaining the goal of achieving near "Fano-limited" performance. Results of this exciting new development from the existing Phase 1 detector will be presented, with measurements achieving 127 eV FWHM at Mn-K operating at 20 fps, including space radiation damage assessments, where performance can be achieved at -40 degrees C compared to -100 degrees C for the CCD technology. At the time of writing this abstract, the work is about to enter its 2nd phase of development towards a 3-sides buttable device of 45x90 mm2 which should find many applications in coming years beyond that of the ESA candidate mission Theseus.

Anton S. Tremsin (Space Sciences Laboratory, University of California at Berkeley, USA)

Title : Recent progress in high resolution photon counting detectors with Microchannel Plates

Detectors with Microchannel Plates have found niche applications in soft X-ray UV and sometimes visible photon detection where event counting with high spatial and timing resolution is needed. Different types of readouts for these detectors have been developed over last several decades. The Timepix readout ASIC placed directly below MCP in the vacuum is one of the possible readout options. The capability of pixelated Timepix readout to detect many simultaneous events substantially increases the count rate capabilities of these devices to GHz levels. In this talk, we review the possible readout configurations for the MCP detectors and present the recent developments of this photon counting technology and present the results obtained with an MCP detector coupled to a quad Timepix/Timepix3 and a single-chip Timepix4 readouts. The spatial resolution of this detector can routinely reach ~6 µm values (the size of the MCP pores). This resolution is achieved in real time through the event cenrtoiding. Optimization of detector characteristics need to be performed in order to achieve such a high spatial resolution. Timing resolution of 1.6 ns with Timepix3 readout and is expected to be better than 200 ps with the latest generation Timepix4 readout. A couple of application examples of these detectors at Resonance Inelastic X-ray Scattering (RIXS) and X-ray Photon Correlation Spectroscopy demonstrate the unique capabilities of such devices for certain synchrotron-based experimental studies. Same MCP/Timepix detectors can be very attractive for the applications where the photon/electron/ion/neutron counting with high spatial and temporal resolution is required, such as Time of Flight experiments in energy-resolving neutron imaging at spallation neutron sources, fluorescence lifetime imaging and, if adapted for the electron detection, experiments on photoelectron spectroscopy.