Commentary: JWST near-infrared detector degradation— finding the problem, fixing the problem, and moving forward (original) (raw)

JWST near infrared detectors: latest test results

SPIE Proceedings, 2009

The James Webb Space Telescope, an infrared-optimized space telescope being developed by NASA for launch in 2013, will utilize cutting-edge detector technology in its investigation of fundamental questions in astrophysics. JWST's near infrared spectrograph, NIRSpec utilizes two 2048 x 2048 HdCdTe arrays with Sidecar ASIC readout electronics developed by Teledyne to provide spectral coverage from 0.6 microns to 5 microns. We present recent test and calibration results for the NIRSpec flight arrays as well as data processing routines for noise reduction and cosmic ray rejection.

Independent testing of JWST detector prototypes

Focal Plane Arrays for Space Telescopes, 2004

The Independent Detector Testing Laboratory (IDTL) is jointly operated by the Space Telescope Science Institute (STScI) and the Johns Hopkins University (JHU), and is assisting the James Webb Space Telescope (JWST) mission in choosing and operating the best near-infrared detectors. The JWST is the centerpiece of the NASA Office of Space Science theme, the Astronomical Search for Origins, and the highest priority astronomy project for the next decade, according to the National Academy of Science. JWST will need to have the sensitivity to see the first light in the Universe to determine how galaxies formed in the web of dark matter that existed when the Universe was in its infancy (z~10-20). To achieve this goal, the JWST Project must pursue an aggressive technology program and advance infrared detectors to performance levels beyond what is now possible. As part of this program, NASA has selected the IDTL to verify comparative performance between prototype JWST detectors developed by Rockwell Scientific (HgCdTe) and Raytheon (InSb). The IDTL is charged with obtaining an independent assessment of the ability of these two competing technologies to achieve the demanding specifications of the JWST program within the 0.6-5 µm bandpass and in an ultra-low background (<0.01 e − /s/pixel) environment. We describe results from the JWST Detector Characterization Project that is being performed in the IDTL. In this project, we are measuring first-order detector parameters, i.e. dark current, read noise, QE, intra-pixel sensitivity, linearity, as functions of temperature, well size, and operational mode.

The Mid-Infrared Instrument for JWST , II: Design and Build

Publications of the Astronomical Society of the Pacific, 2015

The Mid-InfraRed Instrument (MIRI) on the James Webb Space Telescope (JWST) provides measurements over the wavelength range 5 to 28.5 µm. MIRI has, within a single 'package', four key scientific functions: photometric imaging, coronagraphy, single-source low-spectral resolving power (R ∼ 100) spectroscopy, and medium-resolving power (R ∼ 1500 to 3500) integral field spectroscopy. An associated cooler system maintains MIRI at its operating temperature of <6.7 K. This paper describes the driving principles behind the design of MIRI, the primary design parameters, and their realisation in terms of the 'as-built' instrument. It also describes the test programme that led to delivery of the tested and calibrated Flight Model to NASA in 2012, and the confirmation after delivery of the key interface requirements.

NIRCam: development and testing of the JWST near-infrared camera

Space Telescopes and Instrumentation 2010: Optical, Infrared, and Millimeter Wave, 2010

The Near Infrared Camera (NIRCam) is one of the four science instruments of the James Webb Space Telescope (JWST). Its high sensitivity, high spatial resolution images over the 0.6 − 5 µm wavelength region will be essential for making significant findings in many science areas as well as for aligning the JWST primary mirror segments and telescope. The NIRCam engineering test unit was recently assembled and has undergone successful cryogenic testing. The NIRCam collimator and camera optics and their mountings are also progressing, with a brass-board system demonstrating relatively low wavefront error across a wide field of view. The flight model's long-wavelength Si grisms have been fabricated, and its coronagraph masks are now being made. Both the short (0.6 − 2.3 µm) and long (2.4 − 5.0 µm) wavelength flight detectors show good performance and are undergoing final assembly and testing. The flight model subsystems should all be completed later this year through early 2011, and NIRCam will be cryogenically tested in the first half of 2011 before delivery to the JWST integrated science instrument module (ISIM).

Characterization of JWST science performance from commissioning

2022

performance Wavefront error and angular resolution Comparison to optical budget for the telescope and science instruments Shape of the point spread function Transmission and contamination Optical stability on different timescales Routine Wavefront Sensing and Control Micrometeoroids Backgrounds, stray light, and scattered light Near-infrared stray light Mid-infrared thermal self-emission Scattered light features from the rogue path Science instrument performance NIRCam performance NIRCam imaging NIRCam grism time-series NIRCam photometric time-series NIRCam wide field slitless spectroscopy NIRCam coronagraphy NIRCam stray light: Wisps, Claws, and other effects NIRISS performance NIRISS imaging (parallel only) NIRISS single object slitless spectroscopy NIRISS wide field slitless spectroscopy NIRISS aperture masking interferometry NIRISS stray light: the Lightsaber NIRSpec performance Detector noise levels Benefits of a good telescope for NIRSpec: decreased slit losses in the MOS and FS modes Efficiency of the telescope and the instrument: MOS and FS modes Efficiency of the telescope and the instrument: IFS mode NIRSpec fixed slit spectroscopy (FS) Performance Summary NIRSpec integral field spectroscopy (IFS) Performance Summary NIRSpec multi-object spectroscopy NIRSpec bright object time series MIRI performance MIRI imaging MIRI low resolution spectroscopy MIRI medium resolution spectroscopy MIRI coronagraphic imaging Using two science instruments in parallel Coordinated parallels Pure parallels Cross-instrument detector topic: cosmic rays Science Operations Status JWST User Documentation System (JDox) Updates Closing thought