Search NASA⌕ Search

SEARCH · Search NASA

Results for “Photodetectors”

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.

At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Air-transfer production method for large-area picosecond photodetectors

We have designed and prototyped the process steps for the batch production of large-area micro-channel-plate photomultipliers (MCPPMT) using the “air-transfer” assembly process developed with single LAPPD TM modules. Results are presented addressing the challenges of designing a robust package that can transmit large numbers of electrical signals for pad or strip readout from inside the vacuum tube and of hermetically sealing the large-perimeter window–body interface. We have also synthesized a photocathode in a large-area low-aspect-ratio volume and have shown that the micro-channel plates recover their functionality after cathode synthesis. These steps inform a design for a multi-module batch facility employing dual nested low-vacuum and ultra-high-vacuum systems in a small-footprint. The facility design provides full access to multiple MCP-PMT modules prior to hermetic pinch-off for leak-checking and real-time photocathode optimization.

47 OTHER INSTRUMENTATION↗
DOE OSTI2023

Effects of 63 MeV proton irradiation on the performance of MWIR InGaAs/InAsSb nBn photodetectors

An investigation into the effects of 63 MeV proton irradiation on high-sensitivity mid-wave infrared InGaAs/InAsSb nBn devices is performed. Three different structures with various absorber region doping profiles are irradiated and characterized to assess their impact on performance degradation. Minority carrier lifetime is measured using time-resolved photoluminescence and lifetime damage factors are assessed. The majority carrier concentration is determined via capacitance–voltage measurements and dopant introduction rates are calculated. An analysis of dark current density is performed using these material parameters, revealing a reduction in mobility with proton fluence and the emergence of a proton-induced trap energy level. Quantum efficiency is calculated at each proton fluence, and quantum efficiency damage factors show that the graded doping structure exhibits the least reduction of quantum efficiency with dose, attributed to its effective mobility enhancement. Conclusively, detector sensitivity, assessed via shot-noise limited noise-equivalent irradiance, shows that the graded doping structure is the least susceptible to high energy proton irradiation-induced performance degradation.

Physics↗
DOE OSTI2021

Characterization of the DUNE photodetectors and study of the event burst phenomenon

The Deep Underground Neutrino Experiment (DUNE) is an upcoming neutrino physics experiment that will answer some of the most compelling questions in particle physics and cosmology. The DUNE far detectors employ silicon photomultipliers (SiPMs) to detect light produced by charged particles interacting in a large liquid argon time projection chamber (LArTPC). The SiPMs are photosensors consisting of an array of single-photon avalanche diodes (SPAD) operating in Geiger mode. Their high sensitivity and dynamic range, as well as the possibility to fill large surfaces with high-granularity sensors, makes them an ideal choice for DUNE. An international consortium of research groups is currently engaged in a systematic comparison of the performances of the SiPM models that have been custom developed for DUNE by two manufacturers. Such detailed studies, which include gain measurements and a structure study of the dark count rate at 77 K, are meant to determine the best choice of the photodetection system for DUNE, as well as characterize the response of the chosen detectors for the DUNE simulation. Moreover, an investigation of a newly observed phenomenon, in which quick bursts of tens of events at close range are collected in individual SiPMs, is being carried out, which potentially impacts the design of future models and their implementation in particle physics experiments.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2025

Spectral kernel machines with electrically tunable photodetectors

Spectral machine vision collects spectral and spatial information as three-dimensional hypercubes and digitally processes them, which causes a data bottleneck, limiting power efficiency, frame rate, and spectral-spatial resolution. This work introduces spectral kernel machines (SKMs) to overcome these bottlenecks. SKM directly compresses spectral analysis through the output photocurrent and learns from example objects to identify and classify new samples in a "sniff-and-seek" mode. We experimentally demonstrated SKMs with electrically tunable bipolar black phosphorus-molybdenum disulfide (bP-MoS2) photodiodes in the near- and mid-infrared band and silicon photoconductors in the visible band, performing versatile intelligent tasks from chemometrics to semiconductor metrology. This architecture consumed substantially less power and was more than an order of magnitude faster than existing solutions for hyperspectral image analysis, defining an intelligent imaging and sensing paradigm with intriguing possibilities.

Zhang, Dehui↗
DOE OSTI2023

Large Area Picosecond PhotoDetector (LAPPD) definitive tests

The goal of the project was to determine the optimal functional parameters for a new LAPPD, determine the cloud charge radius and test for gain variation due to pore sharing. Also, cosmics tests with C4F8 heavy gas of the new LAPPD were planned.

43 PARTICLE ACCELERATORS↗
NASA NTRS1973

Investigation of responsivity and noise in a direct-coupled photodetector-preamplifier for facsimile cameras

The direct-coupled (DC) mode of detector operation is evaluated for use in a facsimile camera. Photodiode-preamplifier sensitivity is described in terms of photodiode responsivity and possible noise sources resulting from the photodiode and preamplifier. Responsivity and noise limitations are experimentally verified and used to predict photodiode-preamplifier sensitivity under a wide range of operating conditions. Results demonstrate that the DC mode offers advantages in sensitivity and reduced mechanical complexity for facsimile cameras over the more common technique of chopping the radiation and ac amplifying the resultant signal.

Kelly, W. L., IV↗
NASA NTRS1975

Heterojunction III-V alloy photodetectors for high-sensitivity 1.06-micrometers optical receivers

It is pointed out that currently promising technical developments related to the Nd-YAG laser technology at 1.06 micrometers cannot be implemented because of the absence of a suitable detector. Such a detector could possibly be provided in connection with new advances related to the development of the heterojunction III-V alloy photodiode. Details of detector requirements for the considered applications are discussed along with approaches to satisfy these requirements by an appropriate detector design.

Eden, R. C.↗