Wavelength dependence on the space charge collection in CdZnTe detectors

2012 ◽  
Vol 111 (11) ◽  
pp. 113715 ◽  
Author(s):  
Aaron L. Washington ◽  
Lucile C. Teague ◽  
Martine C. Duff ◽  
Arnold Burger ◽  
Michael Groza ◽  
...  
Keyword(s):  
Space Charge ◽  
Wavelength Dependence ◽  
Charge Collection ◽  
Cdznte Detectors

Charge collection in multielectrode CdZnTe detectors

1999 ◽  
Author(s):  
Thomas H. Prettyman ◽  
Morag K. Smith ◽  
Paul N. Luke ◽  
Mark S. Amman ◽  
Julie S. Lee
Keyword(s):  
Charge Collection ◽  
Cdznte Detectors

scholarly journals The mini-JPAS: A Study of the Wavelength Dependence of the Photon Response Nonuniformity of the JPAS-Pathfinder Camera

2021 ◽  
Vol 257 (2) ◽  
pp. 31
Author(s):  
Kai Xiao ◽  
Haibo Yuan ◽  
J. Varela ◽  
Hu Zhan ◽  
Jifeng Liu ◽  
...  
Keyword(s):  
Collection Efficiency ◽  
Wavelength Dependence ◽  
Effective Area ◽  
Photon Absorption ◽  
Charge Collection ◽  
Small Scale ◽  
Model Parameters ◽  
Absorption Length ◽  
Charge Collection Efficiency ◽  
Simple Physical Model

Abstract Understanding the origins of small-scale flats of CCDs and their wavelength-dependent variations plays an important role in high-precision photometric, astrometric, and shape measurements of astronomical objects. Based on the unique flat data of 47 narrowband filters provided by JPAS-Pathfinder, we analyze the variations of small-scale flats as a function of wavelength. We find moderate variations (from about 1.0% at 390 nm to 0.3% at 890 nm) of small-scale flats among different filters, increasing toward shorter wavelengths. Small-scale flats of two filters close in central wavelengths are strongly correlated. We then use a simple physical model to reproduce the observed variations to a precision of about ±0.14% by considering the variations of charge collection efficiencies, effective areas, and thicknesses between CCD pixels. We find that the wavelength-dependent variations of the small-scale flats of the JPAS-Pathfinder camera originate from inhomogeneities of the quantum efficiency (particularly charge collection efficiency), as well as the effective area and thickness of CCD pixels. The former dominates the variations in short wavelengths, while the latter two dominate at longer wavelengths. The effects on proper flat-fielding, as well as on photometric/flux calibrations for photometric/slitless spectroscopic surveys, are discussed, particularly in blue filters/wavelengths. We also find that different model parameters are sensitive to flats of different wavelengths, depending on the relations between the electron absorption depth, photon absorption length, and CCD thickness. In order to model the wavelength-dependent variations of small-scale flats, a small number (around 10) of small-scale flats with well-selected wavelengths are sufficient to reconstruct small-scale flats in other wavelengths.

Identification of single-pixel incomplete charge collection events by using cathode waveform in pixelated CdZnTe detectors

2020 ◽  
Vol 15 (09) ◽  
pp. P09017-P09017
Author(s):  
J. Yang ◽  
Y.L. Li ◽  
Y. Tian ◽  
L. Xu ◽  
Y.M. Cai ◽  
...  
Keyword(s):  
Charge Collection ◽  
Cdznte Detectors ◽  
Single Pixel

A Study Of The Composition Uniformity, Electrical And Spectroscopic Properties Of CdZnTe Detectors

1997 ◽  
Vol 487 ◽  
Author(s):  
M-A. Gagliardi ◽  
S. Nenonen ◽  
T. Gagliardi ◽  
K. T. Hjelt ◽  
M. Juvonen ◽  
...  
Keyword(s):  
Spectroscopic Properties ◽  
Test Methods ◽  
Charge Collection ◽  
Test Results ◽  
Cdznte Detector ◽  
Final Performance ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Cdznte Detectors ◽  
Selection Of

AbstractThe electrical and charge collection properties of a semiconductor detector play an important role in a spectrometer's final performance. However, the studies of these properties often concentrate on only a few samples. In this work over 100 CdZnTe detectors from 12 different growth boules were characterized with one of the following test methods. The composition uniformity was evaluated with low temperature photoluminescence (PL) measurements. From the current-voltage characteristics the differences in CdZnTe detector resistivities were investigated. Charge collection properties, μτ-products, and energy resolutions were characterized with spectroscopic methods using an alpha and isotopic sources. A wide selection of test results are presented indicating the variety of CdZnTe material.

Evaluation of Indium Diffused M-i-n CdZnTe Detectors

1997 ◽  
Vol 487 ◽  
Author(s):  
M-A. Gagliardi ◽  
S. Nenonen ◽  
T. Gagliardi ◽  
L. Aleksejeva ◽  
V. Ivanov ◽  
...  
Keyword(s):  
Leakage Current ◽  
Spectroscopic Properties ◽  
Charge Collection ◽  
Noise Sources ◽  
Junction Formation ◽  
Detector Structure ◽  
Junction Type ◽  
Cdznte Detectors ◽  
Type Detector ◽  
Indium Diffusion

AbstractOne of the main electronic noise sources of a room temperature spectroscopy system is the leakage current of a detector. It can be reduced with a pn-junction type detector structure such as a M-i-n configuration, and with cooling. In this work eight CdZnTe detectors with a M-i-n structure were fabricated by indium diffusion. The junction was characterized by a currentvoltage technique. Detector electrical, charge collection and spectroscopic properties were compared to the ones received with the traditional electroless Au contacts, before the junction formation. As a result of the indium diffusion an improved detector leakage current performance was achieved. However, a corresponding improvement in the detector energy resolution was not always observed due to the CdZnTe charge collection properties and process variables.

Photoinduced Space Charge Effects in a-Si:H Solar Cells

1999 ◽  
Vol 557 ◽  
Author(s):  
T. Unold ◽  
T. Binnewies ◽  
R. Brüggemann ◽  
G.H. Bauer
Keyword(s):  
Numerical Simulation ◽  
Solar Cells ◽  
Space Charge ◽  
Probe Beam ◽  
Defect Density ◽  
Photon Flux ◽  
Charge Collection ◽  
Small Signal ◽  
Charge Effects ◽  
Signal Probe

AbstractWe have investigated charge collection in thin amorphous silicon solar cells under light bias illumination, both experimentally and by numerical simulation. In such charge collection experiments, space charge due to trapped bias-light generated carriers leads to an enhancement of a small signal probe beam charge collection. It is found that this enhancement of the small signal charge collection is strongly dependent on the diode thickness and the defect density in the samples. In particular for thin diodes (d < 0.5 microns) the charge collection enhancement can be shown to increase with light-induced degradation of the devices. The effect of these material parameters as well as other experimental parameters, such as light bias and probe beam photon flux, will be demonstrated by means of numerical simulation.

Polarimetric Observations of Red Variables: A Study of Gas and Particle Interactions

1979 ◽  
Vol 46 ◽  
pp. 386-408 ◽  
Author(s):  
G. V. Coyne ◽  
I. S. McLean
Keyword(s):  
Wavelength Dependence ◽  
Stellar Atmosphere ◽  
Molecular Absorption ◽  
Absorption Bands ◽  
Absorption And Emission ◽  
Mira Variables ◽  
Stellar Photosphere ◽  
Regular Variable ◽  
Red Supergiants ◽  
Balmer Lines

AbstractIn recent years the wavelength, dependence of the polarization in a number of Mira variables, semi-regular variables and red supergiants has been measured with resolutions between 0.3 and 300 A over the range 3300 to 11000 A. Variations are seen across molecular absorption bands, especially TiO bands, and across atomic absorption and emission lines, especially the Balmer lines. In most cases one can ignore or it is possible to eliminate the effects due to interstellar polarization, so that one can study the polarization mechanisms operating in the stellar atmosphere and environment. The stars Omicron Ceti. (Mira), V CVn (semi-regular variable) and Mu Cephei (M2 la), in addition to other stars similar to them, will be discussed in some detail.Models to explain the observed polarization consider that the continuum flux is polarized either by electron, molecular and/or grain scattering or by temperature variations and/or geometrical asymmetries over the stellar photosphere. This polarized radiation is affected by atomic and molecular absorption and emission processes at various geometric depths in the stellar atmosphere and envelope. High resolution spectropolarimetry promises, therefore, to be a power-rul tool for studying stratification effects in these stars.

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