The next generation of soft X-ray telescopes plan to push the boundaries of X-ray astronomy by featuring large increases in effective area. The most difficult observations, such as will be required to fully explore the low-luminosity and high-redshift X-ray Universe, will need to couple this high throughput with very fine angular resolution -- as is currently being studied for the Lynx mission concept. At the focal planes of instruments equipped to carry out this work will be arrays of small pixels (to oversample the telescope point spread function) that are capable of low-noise, rapid readout (to avoid pile-up of X-ray photons). While traditional X-ray charge-coupled devices (CCDs) have now been the workhorse imaging sensors in X-ray astronomy for ~ 25 years, these requirements -- specifically low-noise, rapid readout -- are outside their capabilities. Active pixel sensors (APSs) are a natural alternative due to their highly parallel readout. They also offer several other advantages, including less susceptibility to radiation damage, low power consumption, and nondestructive and windowed readout. Several APS technologies are currently under development; this work focuses on hybrid complementary metal-oxide-semiconductor (CMOS) detectors, with additional smaller-scale discussion of depleted p-channel field-effect transistors (DePFETs). Through detailed characterization of these technologies, this dissertation aims to demonstrate the advancement of hybrid CMOS detectors (HCDs) and DePFETs towards future flagship X-ray space telescopes like Lynx. After briefly reviewing the history and current state of X-ray astronomy, the dissertation continues with a discussion of the physics of soft X-ray detection, along with details on the operation of CCDs, HCDs, and DePFETs. Following this is a description of the design, testing, and full characterization results of prototype small-pixel HCDs -- which have been specifically developed to meet the needs of a Lynx-class observatory. Results include measurements of the read noise, dark current, pixel well capacity, pixel crosstalk, charge diffusion, pixel-to-pixel gain variation, and spectral resolution. The subsequent section features initial testing results from prototype DePFETs sensors, along with a discussion of their possible development path. Finally, the dissertation closes with an exploration of the exciting novel X-ray astronomy that will be possible with future instruments that may utilize these technologies.

Hybrid CMOS detectors (HCD) have provided great benefit to the infrared and optical fields of astronomy, and they are poised to do the same for X-ray astronomy. Infrared HCDs have already flown on the Hubble Space Telescope and the Wide-Field Infrared Survey Explorer (WISE) mission and are slated to fly on the James Webb Space Telescope (JWST). Hybrid CMOS X-ray detectors offer low susceptibility to radiation damage, low power consumption, and fast readout time to avoid pile-up. The fast readout time is necessary for future high throughput X-ray missions. The Speedster-EXD X-ray HCD presented in this dissertation offers new in-pixel features and reduces known noise sources seen on previous generation HCDs. The Speedster-EXD detector makes a great step forward in the development of these detectors for future space missions.This dissertation begins with an overview of future X-ray space mission concepts and their detector requirements. The background on the physics of semiconductor devices and an explanation of the detection of X-rays with these devices will be discussed followed by a discussion on CCDs and CMOS detectors. Next, hybrid CMOS X-ray detectors will be explained including their advantages and disadvantages. The Speedster-EXD detector and its new features will be outlined including its ability to only read out pixels which contain X-ray events. Test stand design and construction for the Speedster-EXD detector is outlined and the characterization of each parameter on two Speedster-EXD detectors is detailed including read noise, dark current, interpixel capacitance crosstalk (IPC), and energy resolution. Gain variation is also characterized, and a Monte Carlo simulation of its impact on energy resolution is described. This analysis shows that its effect can be successfully nullified with proper calibration, which would be important for a flight mission. Appendix B contains a study of the extreme tidal disruption event, Swift J1644+57, to search for periodicities in its X-ray light curve.

This final report summarizes our past activities and discusses the work performed over the period of 1 April 1990 through 1 April 1991 on x-ray optics, soft x-ray (0.1 - 10 KeV) imaging detectors, and hard x-ray (10 - 300 KeV) imaging detectors. If microchannel plates (MCPs) can be used to focus x-rays with a high efficiency and good angular resolution, they will revolutionize the field of x-ray optics. An x-ray image of a point source through an array of square MCP pores compared favorably with our ray tracing model for the MCP. Initial analysis of this image demonstrates the feasibility of MCPs for soft x-rays. Our work continues with optimizing the performance of our soft x-ray MCP imaging detectors. This work involves readout technology that should provide improved MCP readout devices (thin film crossed grid, curved, and resistive sheets), defect removal in MCPs, and photocathode optimization. In the area of hard x-ray detector development we have developed two different techniques for producing a CsI photocathode thickness of 10 to 100 microns, such that it is thick enough to absorb the high energy x-rays and still allow the photoelectrons to escape to the top MCP of a modified soft x-ray imaging detector. The methods involve vacuum depositing a thick film of CsI on a strong back, and producing a converter device that takes the place of the photocathode. Murray, S. S. and Schwartz, D. A. NASA-CR-193653, NAS 1.26:193653 NAG5-605...

This book provides readers a good overview of some of most recent advances in the field of hybrid pixelated detectors for X-ray imaging. Coverage includes both technology and applications, with an in-depth review of the research topics conducted at leading research institutions in the world. The conversion of the X-ray signal into an analogue/digital value is discussed, as well as a review of CMOS chips used for X-ray image sensors. Applications of hybrid pixel detectors are discussed, such as medical imaging, high energy physics, space, non-destructive testing and security. Provides coverage of a broad range of topics, from international experts in academia and industry; Includes in-depth analysis of how to optimize X-ray detection and electronics for X-ray detection; Covers both technology and applications in a number of different domains.

This book offers readers an overview of some of the most recent advances in the field of detectors for X-ray imaging. Coverage includes both technology and applications, with an in-depth review of the research topics from leading specialists in the field. Emphasis is on high-Z materials like CdTe, CZT and perovskites, since they offer the best implementation possibilities for direct conversion X-ray detectors. Authors discuss material challenges, detector operation physics and technology and readout integrated circuits required to detect signals processes by high-Z sensors.