scholarly journals Parallelized Integrated Time-Correlated Photon Counting System for High Photon Counting Rate Applications

2018 ◽  
Author(s):  
Imane Malass ◽  
Wilfried Uhring ◽  
Jean-Pierre Le Normand ◽  
Norbert Dumas ◽  
Foudil Dadouche
Keyword(s):  
Counting Rate ◽  
Photon Counting ◽  
Counting System

Compact, Low-Power and Fully Reconfigurable 10 ps Resolution, 160 Range, Time-Resolved Single-Photon Counting System

2016 ◽  
Vol 16 (10) ◽  
pp. 3827-3833 ◽  
Author(s):  
Davide Tamborini ◽  
Mauro Buttafava ◽  
Alessandro Ruggeri ◽  
Franco Zappa
Keyword(s):  
Low Power ◽  
Single Photon ◽  
Photon Counting ◽  
Counting System ◽  
Time Resolved ◽  
Single Photon Counting

Intracellular free calcium oscillations in normal and cleavage-blocked embryos and artificially activated eggs of Xenopus laevis

1994 ◽  
Vol 107 (8) ◽  
pp. 2229-2237 ◽  
Author(s):  
T.J. Keating ◽  
R.J. Cork ◽  
K.R. Robinson
Keyword(s):  
Xenopus Laevis ◽  
Photon Counting ◽  
Calcium Oscillations ◽  
Intracellular Free Calcium ◽  
Free Calcium ◽  
Counting System ◽  
Normal Medium ◽  
Sinusoidal Oscillations ◽  
Cyclic Changes ◽  
Xenopus Laevis Embryos

We have measured levels of intracellular free calcium ([Ca2+]i) in albino Xenopus laevis embryos using recombinant aequorin and a photon-counting system. We observed sinusoidal oscillations in [Ca2+]i that had the same frequency as cleavage, with cleavage occurring when [Ca2+]i was lowest. An increase in calcium was seen to precede first cleavage. The cyclic changes in calcium were superimposed on a secondary pattern that increased, peaked between third and fifth cleavages and then slowly declined to a level similar to that measured before first cleavage. The amplitude of the oscillations was small during the first few cleavages but became larger with each cycle, with the largest oscillations occurring when the secondary pattern peaked (between third and fifth cleavage). As the secondary pattern declined, the amplitude of the oscillations also became smaller. The oscillations are due to release of calcium from intracellular stores, since the signal was the same in calcium-free solution as in normal medium. When cleavage was blocked with the microtubule-disrupting drugs colchicine or nocodazole, the [Ca2+]i oscillations persisted. Calcium oscillations of a similar magnitude and frequency were also present in artificially activated eggs. The secondary pattern was different in cleavage-blocked embryos and artificially activated eggs, the baseline increasing until about the third cycle and then remaining elevated for the rest of the recording (> 8 hours). By fixing embryos at various points in the calcium cycle, we determined that mitosis began shortly after calcium levels reached their peak and was complete before the calcium level dropped to its lowest point.(ABSTRACT TRUNCATED AT 250 WORDS)

Error Theory Research and Correction on Depth Acquisition Photon Counting System

2017 ◽  
Vol 46 (12) ◽  
pp. 1203001
Author(s):  
沈姗姗 SHEN Shan-shan ◽  
叶荣诚 YE Rong-chen ◽  
陈艳 CHEN Yan
Keyword(s):  
Photon Counting ◽  
Error Theory ◽  
Counting System ◽  
Theory Research

scholarly journals Stellar Atmospheres and Chemical Compositions of Galaxies

1980 ◽  
Vol 5 ◽  
pp. 811-815
Author(s):  
Lawrence H. Aller
Keyword(s):  
Los Angeles ◽  
Photon Counting ◽  
Stellar Atmospheres ◽  
Balmer Line ◽  
Chemical Compositions ◽  
Energy Distributions ◽  
Counting System ◽  
Theoretical Predictions ◽  
External Galaxies ◽  
The University

AbstractThe chemical compositions of external galaxies are usually found from their HII regions or composite absorption line spectra of their nuclei. In the Magellanic Clouds, however, individual stars are observable, but objects heretofore studied necessarily have been luminous la supergiants which border on the brink of instability. The image photon counting system on the Anglo-Australian Telescope makes it possible to observe fainter, more stable Ib supergiants. Energy distributions and Balmer line profiles for these stars can be fitted with theoretical predictions by Kurucz. A joint effort by J.E. Ross and B.J. O’Mara of the University of Queensland, Bruce Peterson of the Anglo-Australian Observatory, and a group at the University of California, Los Angeles to analyze three lb supergiants suggests that metals of the iron group are depleted by a factor of 2-3.5 with respect to the normal chemical composition of our own galaxy.

Single‐photon counting system for measuring laser parameters

1979 ◽  
Vol 50 (8) ◽  
pp. 1013-1017
Author(s):  
T. G. Miller ◽  
D. R. Womack ◽  
J. R. Williams ◽  
M. J. Monahan ◽  
Q. C. Murphree
Keyword(s):  
Single Photon ◽  
Photon Counting ◽  
Counting System ◽  
Single Photon Counting ◽  
Laser Parameters
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