Multiplier Photo-Tube Characteristics: Application to Low Light Levels*

Engstrom, R. W.

doi:10.1364/josa.37.000420

Cited by 206 publications

(23 citation statements)

References 22 publications

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“…Also the area of saturation in the upper right corner retreated to some extent, which is likely to be caused by shorter decays limiting the space charge build-up time at the end of the dynode chain. [16][17][18] The lifetime gradient for low light intensities (present in Figure 8) has vanished and some elements at low gains and intensities remained empty due to signal-to-noise (S/N) issues at shorter decays.…”

Section: Resultsmentioning

confidence: 99%

Comparison of photo detectors and operating conditions for decay time determination in phosphor thermometry

Knappe

Nada

Richter

et al. 2012

Review of Scientific Instruments

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M. (2012). Comparison of photo detectors and operating conditions for decay time determination in phosphor thermometry. Review of Scientific Instruments, 83(9), [094901]. DOI: 10.1063/1.4746990 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal This work compares the extent of linear response regions from standard time-resolving optical detectors for phosphor thermometry. Different types of photomultipliers (ordinary and time-gated) as well as an avalanche photodiode were tested and compared using the phosphorescence decay time of cadmium tungstate (CdWO 4 ). Effects originating from incipient detector saturation are revealed as a change in evaluated phosphorescence decay time, which was found to be a more sensitive measure for saturation than the conventional signal strength comparison between in-and output. Since the decay time of thermographic phosphors is used for temperature determination systematic temperature errors in the order of several tens of Kelvins may be introduced. Saturation from the initial intensity is isolated from temporally developed saturation by varying the CdWO 4 decay time over the microsecond to nanosecond range, resultant of varying the temperature from 290 to 580 K. A detector mapping procedure is developed in order to identify linear response regions where the decay-to-temperature evaluations are unbiased. In addition, this mapping procedure generates a library of the degree of distortion for operating points outside of linear response regions. Signals collected in the partly saturated regime can thus be corrected to their unbiased value using this library, extending the usable detector operating range significantly.

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Section: Resultsmentioning

confidence: 99%

Comparison of photo detectors and operating conditions for decay time determination in phosphor thermometry

Knappe

Nada

Richter

et al. 2012

Review of Scientific Instruments

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“…With a photodiode detector, the electrical noise is usually a parameter of the diode or its associated amplifier and is not greatly dependent upon the level of illumination. For a photomultiplier, however, the noise is mainly due to the photoelectric emission process and is proportional to the square root of the illumination [16,17].…”

Section: Photoelectric Detectionmentioning

confidence: 99%

Signal Strength in Two-beam Interferometers with Laser Illumination

Rowley

1969

Optica Acta: International Journal of Optics

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“…If we assume that our receiver has a 1 .& filter before the detector, we find [from (8)] that it receives 2.4X1O-l1 W of noise from the background.…”

Section: System Bandwidth and Noisementioning

confidence: 99%

Some parameters of a laser-type beyond-the-horizon communication link

King

Kainer²

1965

Proc. IEEE

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This paper discusses beyond-the-horizon propagation of laser beams by means of scattering from clouds and hazes as applied to communication systems. Expressions for the information capacity of such a communication link are derived from consideration of the scattering properties of such clouds and hazes and from other system parameters. A more detailed investigation of the properties and potentialities of such a communication system seems warranted.T GENERAL HE TECHNIQUE of tropospheric scatter propagation has been applied to microwave communication links with considerable success. Over-thehorizon links operating on the common carrier bands with information bandwidths of about 10 Mc/s have been operated reliably. Microwave links of this type have reached an accommodation with the problems of diffraction loss, scatter loss, fading, noise, etc.What we will discuss here are the parameters of a laser-type beyond-the-horizon scatter communication link. The scattering medium will be atmospheric water in the form of clouds and hazes. Clouds in the earth's atmosphere are quite abundant. At any given time, about 50 per cent of the earth's surface is under cloud cover. In this paper we will use the term optical transmitter to imply a coherent or laser-type optical source, such as a gaseous or semiconductor laser. DETAILED DISCCSSION OF AN OPTICAL SCATTER PROPAGATION LINK Scatter From Clouds and HazesConsider a beam of light impacting upon a scattering medium consisting of spherical water droplets of various sizes. As the beam progresses through the medium, more and more of its energy is scattered in all directions by the water droplets. The angular distribution of the scattered light is a complicated function of the wavelength of the light and the size distribution of the water droplets.Statistics have been compiled on the size distribution of water drops in two types of haze and one type of cloud [l]. Figure 1 shows the absolute droplet distribution n ( r ) (units of ~m -~ p-l) as a function of radius r for three different atmospheric conditions.That is, the number of droplets per cubic centimeter of radius r to r+dr is given by n(r)dr. Curve HI shows a distribution M. King is presently with the Department of Electrical EngiManuscript received June 29; revised October 13, 1964.. neering, Columbia University, New York, N. Y., on leave from I T T Federal Labs., Nutley, N. J. S. Kainer is with ITT Federal Labs., Nutley, N. J. Io+ t I O ' w ) , cmJ$ IO' IO" Id' 0.01 0. I I .o IO r 1 P Fig. 1. Droplet distributions (after Deirmendjian [l]).for a haze indigenous to coastal areas, curve Hz shows the distribution for a typical continental haze, and curve Cl shows the density function for a cumulus cloud having a depth of 230 to 2100 m. To get the total scattering and absorption cross sections per unit volume of the cloud or haze, one has to integrate the single-particle cross sections of the M e scattering theory with respect to the appropriate distribution. The resultant cross section will be characteristic of singly scattered ra...

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Multiplier Photo-Tube Characteristics: Application to Low Light Levels*

Cited by 206 publications

References 22 publications

Comparison of photo detectors and operating conditions for decay time determination in phosphor thermometry

Comparison of photo detectors and operating conditions for decay time determination in phosphor thermometry

Signal Strength in Two-beam Interferometers with Laser Illumination

Some parameters of a laser-type beyond-the-horizon communication link

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