Smartphone scene generator for efficient characterization of visible imaging detectors

Full characterization of imaging detectors involves subjecting them to spatially and temporally varying illumination patterns over a large dynamic range. Here we present a scene generator that fulfills many of these functions. Based on a modern smartphone, it has a number of good features, including the ability to generate nearly arbitrary optical scenes, high spatial resolution (13 um), high dynamic range (~10^4), near-Poisson limited illumination stability over time periods from 100 ms to many days, and no background noise. The system does not require any moving parts and may be constructed at modest cost. We present the optical, mechanical, and software design, test data validating the performance, and application examples.Comment: 14 pages. This version includes code, available here: https://github.com/Leo-Nea

Vacuum-Compatible Wideband White Light and Laser Combiner Source System

For the Space Interferometry Mission (SIM) Spectrum Calibration Development Unit (SCDU) testbed, wideband white light is used to simulate starlight. The white light source mount requires extremely stable pointing accuracy (<3.2 microradians). To meet this and other needs, the laser light from a single-mode fiber was combined, through a beam splitter window with special coating from broadband wavelengths, with light from multimode fiber. Both lights were coupled to a photonic crystal fiber (PCF). In many optical systems, simulating a point star with broadband spectrum with stability of microradians for white light interferometry is a challenge. In this case, the cameras use the white light interference to balance two optical paths, and to maintain close tracking. In order to coarse align the optical paths, a laser light is sent into the system to allow tracking of fringes because a narrow band laser has a great range of interference. The design requirements forced the innovators to use a new type of optical fiber, and to take a large amount of care in aligning the input sources. The testbed required better than 1% throughput, or enough output power on the lowest spectrum to be detectable by the CCD camera (6 nW at camera). The system needed to be vacuum-compatible and to have the capability for combining a visible laser light at any time for calibration purposes. The red laser is a commercially produced 635-nm laser 5-mW diode, and the white light source is a commercially produced tungsten halogen lamp that gives a broad spectrum of about 525 to 800 nm full width at half maximum (FWHM), with about 1.4 mW of power at 630 nm. A custom-made beam splitter window with special coating for broadband wavelengths is used with the white light input via a 50-mm multi-mode fiber. The large mode area PCF is an LMA-8 made by Crystal Fibre (core diameter of 8.5 mm, mode field diameter of 6 mm, and numerical aperture at 625 nm of 0.083). Any science interferometer that needs a tracking laser fringe to assist in alignment can use this system

Electron multiplication CCD detector technology advancement for the WFIRST-AFTA coronagraph

The WFIRST-AFTA (Wide Field InfraRed Survey Telescope-Astrophysics Focused Telescope Asset) is a NASA space observatory. It will host two major astronomical instruments: a wide-field imager (WFI) to search for dark energy and carry out wide field near infrared (NIR) surveys, and a coronagraph instrument (CGI) to image and spectrally characterize extrasolar planets. In this paper, we discuss the work that has been carried out at JPL in advancing Electron Multiplying CCD (EMCCD) technology to higher flight maturity, with the goal of reaching a NASA technology readiness level of 6 (TRL-6) by early-to-mid 2016. The EMCCD has been baselined for both the coronagraph's imager and integral field spectrograph (IFS) based on its sub-electron noise performance at extremely low flux levels - the regime where the AFTA CGI will operate. We present results from a study that fully characterizes the beginning of life performance of the EMCCD. We also discuss, and present initial results from, a recent radiation test campaign that was designed and carried out to mimic the conditions of the WFIRST-AFTA space environment in an L2 orbit, where we sought to assess the sensor's end of life performance, particularly degradation of its charge transfer efficiency, in addition to other parameters such as dark current, electron multiplication gain, clock induced charge and read noise

WFIRST coronagraph detector trap modeling results and improvements

The WFIRST coronagraph is being designed to detect and characterize mature exoplanets through the starlight reflected from their surfaces and atmospheres. The light incident on the detector from these distant exoplanets is estimated to be on the order of a few photons per pixel per hour. To measure such small signals, the project has baselined the CCD201 detector made by e2v, a low-noise and high-efficiency electron-multiplying charge-coupled device (EMCCD), and has instituted a rigorous test and modeling program to characterize the device prior to flight. An important consideration is detector performance degradation over the proposed mission lifetime due to radiation exposure in space. To quantify this estimated loss in performance, the project has built a detector trap model that takes into account detailed trap interactions at the sub-pixel level, including stochastic trap capture and release, and the deferment of charge into subsequent pixels during parallel and serial clocking of the pseudo-two-phase CCD201 device. This paper describes recent detector trap model improvements and modeling results

Technology advancement of the CCD201-20 EMCCD for the WFIRST coronagraph instrument: sensor characterization and radiation damage

The Wide Field InfraRed Survey Telescope-Astrophysics Focused Telescope Asset (WFIRST-AFTA) mission is a 2.4-m class space telescope that will be used across a swath of astrophysical research domains. JPL will provide a high-contrast imaging coronagraph instrument—one of two major astronomical instruments. In order to achieve the low noise performance required to detect planets under extremely low flux conditions, the electron multiplying charge-coupled device (EMCCD) has been baselined for both of the coronagraph’s sensors—the imaging camera and integral field spectrograph. JPL has established an EMCCD test laboratory in order to advance EMCCD maturity to technology readiness level-6. This plan incorporates full sensor characterization, including read noise, dark current, and clock-induced charge. In addition, by considering the unique challenges of the WFIRST space environment, degradation to the sensor’s charge transfer efficiency will be assessed, as a result of damage from high-energy particles such as protons, electrons, and cosmic rays. Science-grade CCD201-20 EMCCDs have been irradiated to a proton fluence that reflects the projected WFIRST orbit. Performance degradation due to radiation displacement damage is reported, which is the first such study for a CCD201-20 that replicates the WFIRST conditions. In addition, techniques intended to identify and mitigate radiation-induced electron trapping, such as trap pumping, custom clocking, and thermal cycling, are discussed

Differences in the carcinogenic evaluation of glyphosate between the International Agency for Research on Cancer (IARC) and the European Food Safety Authority (EFSA)

The International Agency for Research on Cancer (IARC) Monographs Programme identifies chemicals, drugs, mixtures, occupational exposures, lifestyles and personal habits, and physical and biological agents that cause cancer in humans and has evaluated about 1000 agents since 1971. Monographs are written by ad hoc Working Groups (WGs) of international scientific experts over a period of about 12 months ending in an eight-day meeting. The WG evaluates all of the publicly available scientific information on each substance and, through a transparent and rigorous process,1 decides on the degree to which the scientific evidence supports that substance's potential to cause or not cause cancer in humans. For Monograph 112,2 17 expert scientists evaluated the carcinogenic hazard for four insecticides and the herbicide glyphosate.3 The WG concluded that the data for glyphosate meet the criteria for classification as a probable human carcinogen. The European Food Safety Authority (EFSA) is the primary agency of the European Union for risk assessments regarding food safety. In October 2015, EFSA reported4 on their evaluation of the Renewal Assessment Report5 (RAR) for glyphosate that was prepared by the Rapporteur Member State, the German Federal Institute for Risk Assessment (BfR). EFSA concluded that ?glyphosate is unlikely to pose a carcinogenic hazard to humans and the evidence does not support classification with regard to its carcinogenic potential?. Addendum 1 (the BfR Addendum) of the RAR5 discusses the scientific rationale for differing from the IARC WG conclusion. Serious flaws in the scientific evaluation in the RAR incorrectly characterise the potential for a carcinogenic hazard from exposure to glyphosate. Since the RAR is the basis for the European Food Safety Agency (EFSA) conclusion,4 it is critical that these shortcomings are corrected

Measurement of the W-boson mass in pp collisions at √s=7 TeV with the ATLAS detector

A measurement of the mass of the W boson is presented based on proton–proton collision data recorded in 2011 at a centre-of-mass energy of 7 TeV with the ATLAS detector at the LHC, and corresponding to 4.6 fb−1 of integrated luminosity. The selected data sample consists of 7.8×106 candidates in the W→μν channel and 5.9×106 candidates in the W→eν channel. The W-boson mass is obtained from template fits to the reconstructed distributions of the charged lepton transverse momentum and of the W boson transverse mass in the electron and muon decay channels, yielding mW=80370±7 (stat.)±11(exp. syst.) ±14(mod. syst.) MeV =80370±19MeV, where the first uncertainty is statistical, the second corresponds to the experimental systematic uncertainty, and the third to the physics-modelling systematic uncertainty. A measurement of the mass difference between the W+ and W−bosons yields mW+−mW−=−29±28 MeV

Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018.

Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field