scholarly journals A SOLAR MID-INFRARED TELESCOPE

2019 ◽  
Vol 55 (1) ◽  
pp. 11-16
Author(s):  
J. E. Mendoza-Torres ◽  
J. S. Palacios-Fonseca ◽  
M. Velázquez-de-la-Rosa ◽  
P. Rodríguez-Montero ◽  
A. De-Roa-Campoy ◽  
...  
Keyword(s):  
Control Systems ◽  
Focal Plane ◽  
Angular Resolution ◽  
Signal To Noise Ratio ◽  
Black Body ◽  
Field Of View ◽  
Solar Telescope ◽  
Signal To Noise ◽  
Mid Infrared ◽  
Infrared Telescope

We developed a mid infrared (MIR) solar telescope, centered at 10 µm. Various optical layouts were analyzed based on computer simulations and a RitcheyChretien 6-inches telescope was selected with a plate scale of 2.5′′/mm using a pyroelectric 4 × 16 pixels detector. The angular resolution is 36′′/pixel with a field of view of 9.6′×2.4′. Two germanium filters are used, one at the aperture of thetelescope and another near its focal plane. The detector was characterized with alaboratory black-body. The count values follow a linear relation with the blackbody temperature. The control systems for both the telescope and the detectorwere developed. Proper mechanical supports were designed for the filters, detectorand electronics. The system has been integrated and a user interface was developed. Preliminary observations have been made giving a signal-to-noise ratio of ≈ 1000.

Fourier Transform Infrared Spectrochemical Imaging: Review of Design and Applications with a Focal Plane Array and Multiple Beam Synchrotron Radiation Source

2012 ◽  
Vol 66 (5) ◽  
pp. 475-491 ◽  
Author(s):  
Carol J. Hirschmugl ◽  
Kathleen M. Gough
Keyword(s):  
Synchrotron Radiation ◽  
Focal Plane ◽  
Signal To Noise Ratio ◽  
Focal Plane Array ◽  
Quality Data ◽  
Small Scale ◽  
Signal To Noise ◽  
High Quality ◽  
Mid Infrared ◽  
Noise Ratio

The beamline design, microscope specifications, and initial results from the new mid-infrared beamline (IRENI) are reviewed. Synchrotron-based spectrochemical imaging, as recently implemented at the Synchrotron Radiation Center in Stoughton, Wisconsin, demonstrates the new capability to achieve diffraction limited chemical imaging across the entire mid-infrared region, simultaneously, with high signal-to-noise ratio. IRENI extracts a large swath of radiation (320 hor. × 25 vert. mrads 2 ) to homogeneously illuminate a commercial infrared (IR) microscope equipped with an IR focal plane array (FPA) detector. Wide-field images are collected, in contrast to single-pixel imaging from the confocal geometry with raster scanning, commonly used at most synchrotron beamlines. IRENI rapidly generates high quality, high spatial resolution data. The relevant advantages (spatial oversampling, speed, sensitivity, and signal-to-noise ratio) are discussed in detail and demonstrated with examples from a variety of disciplines, including formalin-fixed and flash-frozen tissue samples, live cells, fixed cells, paint cross-sections, polymer fibers, and novel nanomaterials. The impact of Mie scattering corrections on this high quality data is shown, and first results with a grazing angle objective are presented, along with future enhancements and plans for implementation of similar, small-scale instruments.

scholarly journals High Signal-to-Noise Ratio Mid-Infrared Quasar Spectral Templates

2013 ◽  
Vol 9 (S304) ◽  
pp. 315-318
Author(s):  
Allison R. Hill ◽  
S. C. Gallagher ◽  
R. P. Deo ◽  
E. Peeters ◽  
Gordon T. Richards
Keyword(s):  
Star Formation ◽  
Signal To Noise Ratio ◽  
Host Galaxy ◽  
High Signal ◽  
Host Galaxies ◽  
Signal To Noise ◽  
Mid Infrared ◽  
High Ionization ◽  
Noise Ratio ◽  
Luminous Objects

AbstractMid-infrared (MIR) quasar spectra exhibit a suite of emission features including high ionization coronal lines from the narrow line region (NLR) illuminated by the ionizing continuum, and hot dust features from grains, as well as polycyclic aromatic hydrocarbons (PAH) features from star formation in the host galaxy. Few features are detected in most spectra because of typically low signal-to-noise ratio (S/N) data. By generating spectral composites in three different luminosity bins from over 180 Spitzer Ifnfrared Spectrograph (IRS) observations, we boost the S/N and reveal important features in the complex spectra. We detect high-ionization, forbidden emission lines in all templates, PAH features in all but the most luminous objects, and broad silicate and graphite features in emission whose strength increases relative to the continuum with luminosity. We find that the intrinsic quasar spectrum for all luminosity templates is consistent, and the differences in the spectra can be explained by host galaxy contamination in the lower luminosity templates. We also posit that star formation may be active in most quasar host galaxies, but the spectral features of star formation are only detectable if the quasar is faint.

scholarly journals Analysis of Signal to Noise Ratio in Coronagraph Observations of Coronal Mass Ejections

2020 ◽  
Author(s):  
Johannes Hinrichs ◽  
Jackie A. Davies ◽  
Matthew J. West ◽  
Volker Bothmer ◽  
Bram Bourgoignie ◽  
...  
Keyword(s):  
Coronal Mass Ejections ◽  
Signal To Noise Ratio ◽  
European Space Agency ◽  
Leading Edge ◽  
Outer Edge ◽  
Field Of View ◽  
Signal To Noise ◽  
Space Agency ◽  
Noise Ratio ◽  
Improved Performance

<p>Aims. We analyse the Signal-to-Noise Ratio (SNR) requirements of the European Space Agency (ESA)-funded Solar Coronagraph for OPErations (SCOPE) instrument with respect to the manual and automatic detection of Coronal Mass Ejections (CMEs) in its field of view of 2.5 to 30 solar radii.<br />Methods. For our analysis, SNR values are estimated from observations made by the C3 coronagraph on the Solar and Heliospheric Observatory (SOHO) spacecraft for a number of di erent CMEs. Additionally, we generate a series of artificial coronagraph images, each consisting of a modelled coronal background and a CME, the latter simulated using the Graduated Cylindrical Shell (GCS) model together with the SCRaytrace code available in the Interactive Data Language (IDL) SolarSoft library. Images are created with CME SNR levels between 0.5 and 10 at the outer<br />field of view (FOV) edge, generated by adding Poisson noise, and velocities between 700 km s-1 and 2800 kms-1. The images are analysed for the detectability of the CME above the noise with the automatic CME detection tool CACTus.<br />Results. We find in the analysed C3 images that CMEs near the outer edge of the field of view are typically 2%of the total brightness and have an SNR between 1 and 4 at their leading edge. The automated detection of CMEs in our simulated images by CACTus succeeded well down to SNR = 1 and for CME velocities up to 1400 kms-1. At lower SNR and higher velocity of 2100 kms-1 the detection started to break down. For SCOPE, the results from the two approaches confirm that the initial design goal of SNR = 4 would, if achieved, deliver improved performance over established data used in operations today.</p>

scholarly journals Impact of Micro-, Mini- and Multi-Electrode Mapping on Ventricular Substrate Characterisation

2020 ◽  
Vol 9 (3) ◽  
pp. 128-135
Author(s):  
Benjamin Berte ◽  
Katja Zeppenfeld ◽  
Roderick Tung
Keyword(s):  
Ventricular Tachycardia ◽  
Cardiac Arrhythmias ◽  
Signal To Noise Ratio ◽  
Near Field ◽  
Field Of View ◽  
Ablation Catheter ◽  
Signal To Noise ◽  
Voltage Mapping ◽  
Practice Variations ◽  
Catheter Technology

Accurate substrate characterisation may improve the evolving understanding and treatment of cardiac arrhythmias. During substrate-based ablation techniques, wide practice variations exist with mapping via dedicated multi-electrode catheter or conventional ablation catheters. Recently, newer ablation catheter technology with embedded mapping electrodes have been introduced. This article focuses on the general misconceptions of voltage mapping and more specific differences in unipolar and bipolar signal morphology, field of view, signal-to-noise ratio, mapping capabilities (density and resolution), catheter-specific voltage thresholds and impact of micro-, mini- and multi-electrodes for substrate mapping. Efficiency and cost-effectiveness of different catheter types are discussed. Increasing sampling density with smaller electrodes allows for higher resolution with a greater likelihood to record near-field electrical information. These advances may help to further improve our mechanistic understanding of the correlation between substrate and ventricular tachycardia, as well as macro-reentry arrhythmia in humans.

The effect of activity outside the field-of-view on image signal-to-noise ratio for 3D PET with15O

2011 ◽  
Vol 56 (10) ◽  
pp. 3061-3072 ◽  
Author(s):  
Masanobu Ibaraki ◽  
Shigeki Sugawara ◽  
Kazuhiro Nakamura ◽  
Fumiko Kinoshita ◽  
Toshibumi Kinoshita
Keyword(s):  
Signal To Noise Ratio ◽  
Field Of View ◽  
Signal To Noise ◽  
Noise Ratio ◽  
3D Pet

scholarly journals Sensitivity of edge illumination X-ray phase-contrast imaging

2014 ◽  
Vol 372 (2010) ◽  
pp. 20130128 ◽  
Author(s):  
P. C. Diemoz ◽  
M. Endrizzi ◽  
A. Bravin ◽  
I. K. Robinson ◽  
A. Olivo
Keyword(s):  
Theoretical Model ◽  
Phase Contrast ◽  
Angular Resolution ◽  
Signal To Noise Ratio ◽  
Phase Contrast Imaging ◽  
High Angular Resolution ◽  
Contrast Imaging ◽  
Signal To Noise ◽  
X Ray ◽  
Set Up

Recently, we developed a theoretical model that can predict the signal-to-noise ratio for edge-like features in phase-contrast images. This model was then applied for the estimation of the sensitivity of three different X-ray phase-contrast techniques: propagation-based imaging, analyser-based imaging and grating interferometry. We show here how the same formalism can be used also in the case of the edge illumination (EI) technique, providing results that are consistent with those of a recently developed method for the estimation of noise in the retrieved refraction image. The new model is then applied to calculate, in the case of a given synchrotron radiation set-up, the optimum positions of the pre-sample aperture and detector edge to maximize the sensitivity. Finally, an example of the extremely high angular resolution achievable with the EI technique is presented.

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