SEARCH · Search NASA
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
This GUI explores various whether various adaptive optics control-related parameter can reach NASA's Habitable Worlds Observatory mission requirement of 10 pm rms over 10 minutes, building off of Fig. 4 in Douglas et al. 2019 (DOI: 10.3847/1538-3881/aaf385).
Multiple-Amplifier Sensing (MAS) charge-coupled devices (CCDs) have recently been shown to be promising silicon detectors that meet noise sensitivity requirements for next generation Stage-5 spectroscopic surveys and potentially, future space-based imaging of extremely faint objects on missions such as the Habitable Worlds Observatory. Building upon the capability of the Skipper CCD to achieve deeply sub-electron noise floors, MAS CCDs utilize multiple floating-gate amplifiers along the serial register to increase the readout speed by a factor of the number of output nodes compared to a Skipper CCD. We introduce and experimentally demonstrate on a 16-channel prototype device new readout techniques that exploit the MAS CCD’s floating-gate amplifiers to optimize the correlated double sampling by resetting once per line instead of once per pixel. With this new mode, we find an optimal filter to subtract the noise from the signal during read out. We also take advantage of the MAS CCD’s structure to tune the read time by independently changing integration times for the signal and reference level. Together with optimal weighted averaging of the 16 outputs, these approaches enable us to reach a sub-electron noise of 0.9 e − rms pix −1 at 19 μs pix −1 for a single charge measurement per pixel—simultaneously giving a 30% faster readout time and 10% lower read noise compared to performance previously evaluated without these techniques.
We present a candidate sensor for future spectroscopic applications, such as a Stage-5 Spectroscopic Survey Experiment or the Habitable Worlds Observatory. This type of charge-coupled device (CCD) sensor features multiple in-line amplifiers at its output stage allowing multiple measurements of the same charge packet, either in each amplifier or in the different amplifiers. Recently, the operation of an eight-amplifier sensor has been experimentally demonstrated, and we present the operation of a 16-amplifier sensor. This new sensor enables a noise level of ∼1 erms− with a single sample per amplifier. In addition, it is shown that sub-electron noise can be achieved using multiple samples per amplifier. In addition to demonstrating the performance of the 16-amplifier sensor, we aim to create a framework for future analysis and performance optimization of this type of detectors. New models and techniques are presented to characterize specific parameters, which are absent in conventional CCDs and Skipper CCDs: charge transfer between amplifiers and independent and common noise in the amplifiers and their processing.
This document is a summary of work completed in June through July 2024 to assess the feasibility of implementing non-coronagraphic pupil chopping (PC) for Habitable Worlds Observatory (HWO) primary mirror segment stabilization with an on- and/or off-axis Natural Guide Star (NGS) or Laser Guide Star (LGS). This work considers three different PC configurations: (1) a non-common path (NCP) continuous low-order Deformable Mirror (DM), (2) using the telescope’s primary mirror (M1) segment(s), and (3) using a NCP low-order segmented DM. We show that option 2 likely needs a LGS for guiding, while options 1 and 3 may be able to guide on NGSs. We also separately evaluate spectral bandwidth limitations in the absence of photon noise, showing that the technique is limited to Δλ/λ ≲ 25% in a standard imaging configuration but Δλ/λ ≲ 150% when using a NCP Wynne corrector.