An Improved Approach To Characterizing And Presenting Streak Camera Performance

Wiedwald, J. D.; Jones, Bobby A.

doi:10.1117/12.949884

Cited by 3 publications

(1 citation statement)

References 1 publication

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“…Tests have shown that the intensity of the halo is two to four orders of magnitude below the peak. 4 Reducing the gap will reduce the halo diameter and increase its brightness. Using a collimator at the screen is a likely method of controlling this problem.…”

Section: Screen Elastic Scatteringmentioning

confidence: 99%

<title>Unique microchannel plate process doubles MCPI resolution</title>

Thomas

Power

1995

SPIE Proceedings

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Applying a dielectric layer to the output of a microchannel plate (MCP) has allowed the screen voltage of a sealed microchannel-plate intensifier tube (MCPI) to be raised to over 10 kV, producing a field strength of 36 kV/mm without any detectable field emission or breakdown of the MCP/screen gap. Tube resolution exceeded 16 lp/mm at 50% modulation.Breakdown is higher in a dieleciric than in a vacuum. In a concept being patented by Gary Power, a few-rim-thick layer of a dielectric was sputtered onto the output surface ofan 18-mm MCP, which was incorporated into a tube under a contract for four tube starts. This process is applicable to any device incorporating a proximity-focused MCP and screen, including streak tubes and gated MCP x-ray imagers.Other improvements discussed include a patented use of a collimator for eliminating the electrons that are elastically scattered from the screen. This methodalsoprovides forfurther improvementin screen gaplimitedresolution to any desired degree by eliminating electrons with high transverse energy. This occurs at the expense of output brightness, which can be recovered through an appropriate increase in screen voltage.

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Section: Screen Elastic Scatteringmentioning

confidence: 99%

<title>Unique microchannel plate process doubles MCPI resolution</title>

Thomas

Power

1995

SPIE Proceedings

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Resolution characteristics of Lawrence Livermore National Laboratory soft x-ray streak cameras

Glendinning

Medecki

1986

Review of Scientific Instruments

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Eight Lawrence Livermore National Laboratory (LLNL) x-ray streak cameras have been characterized for spatial resolution and for the line spread function contribution to the temporal resolution. The contrast transfer function of a gold resolution grid of varying spatial frequency was measured for each camera. In addition, the image intensifier tube normally used for LLNL streak cameras (ITT 4113) was characterized separately. Limiting visual resolution for the system was found at 10 line pairs/mm (lp/mm) at camera photocathode with a corresponding temporal line spread function of 440 μm FWHM. Limiting visual resolution for the intensifier was found at 14 lp/mm at intensifier photocathode. Comparisons to commerical streak camera models are underway.

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Time-resolved spectrofluorometer for clinical tissue characterization during endoscopy

Glanzmann

Ballini

Bergh

et al. 1999

Review of Scientific Instruments

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Time-resolved fluorescence spectroscopy has the potential to provide more information for the detection of early cancer than continuous wave spectroscopy. A new optical fiber-based spectrofluorometer for time-resolved fluorescence spectroscopy of biological tissue during clinical endoscopy is presented. The apparatus is based on a nitrogen laser pumping a dye laser as excitation source and a streak camera coupled with a spectrograph as time-resolved spectrometer. The excitation and fluorescence light is carried by an optical fiber to the tissue under investigation and back to the detector, respectively. This optical fiber can be inserted into the biopsy channel of a conventional endoscope. Hence, the apparatus can be used to perform in situ tissue characterization during endoscopy. The instrument enables the measurement of the decays of entire fluorescence spectra within 15 s with a dynamic range of the spectro-temporal images of up to three orders of magnitude. Luminescence lifetimes from the sub ns up to the ms range can be measured. Spectral and temporal resolution, sensitivity, and dynamic range of the instrumentation were determined. The accuracy of the apparatus was checked by the measurement of the fluorescence lifetimes of various fluorophores with known lifetimes. For the first time, two-dimensional time-resolved spectra with sub-ns temporal resolution of tissue fluorescence of the human bladder, the bronchi, and the esophagus taken during endoscopy are presented as a demonstration of performance of the instrumentation. The excitation wavelengths were 337 nm in the case of the bladder and the esophagus and 480 nm in the case of the bronchi. Lifetime contrasts between normal and neoplastic tissue were found in all three organs. The spectral analysis of the fluorescence decays showed that the fluorescence between 370 and 490 nm, excited at 337 nm, consisted in several overlapping spectra. In the case of the esophagus, the contrast between normal and tumoral tissue was inverse in two different spectral bands proving the importance of the choice of the appropriate spectral range for time-resolved autofluorescence measurements for an optimal contrast. The in vivo fluorescence decay of the photosensitizers 5-aminolevulinic acid hexylester hydrochloride-induced protoporphyrin IX was measured in the human bladder and found to be mono-exponential with a lifetime of 15.9 (±1.2) ns. An in vivo fluorescence lifetime of 8.5 (±0.8) ns was found in the case of the photosensitizer 5, 10, 15, 20-tetra(m-hydroxyphenyl)chlorin (mTHPC) in the esophagus.

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An Improved Approach To Characterizing And Presenting Streak Camera Performance

Abstract: This is a preprint of a paper intended for publication in a journal or proceedings. Since changes may be made before publication, this preprint is made available with the un derstanding that it will not be cited or reproduced without the permission of the author.

Cited by 3 publications

References 1 publication

<title>Unique microchannel plate process doubles MCPI resolution</title>

<title>Unique microchannel plate process doubles MCPI resolution</title>

Resolution characteristics of Lawrence Livermore National Laboratory soft x-ray streak cameras

Time-resolved spectrofluorometer for clinical tissue characterization during endoscopy

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