scholarly journals Performance of CsI:Tl Cyrstal with a Spectrum Matching Photomultiplier Tube.

2020 ◽  
Author(s):  
Pin Yang ◽  
Carolina Gomez ◽  
Charles Harmon
Keyword(s):  
Photomultiplier Tube ◽  
Spectrum Matching

Laser-Excited Fluorescence of Dityrosine

1995 ◽  
Vol 49 (11) ◽  
pp. 1669-1676 ◽  
Author(s):  
Sahar F. Mahmoud ◽  
Stephen E. Bialkowski
Keyword(s):  
Ferrous Iron ◽  
Ferric Iron ◽  
Iron Concentration ◽  
Fluorescence Emission ◽  
Fluorescence Yield ◽  
Photomultiplier Tube ◽  
Alkaline Solutions ◽  
Array Detector ◽  
Fluorescence Maximum ◽  
Fluorescence Efficiency

In this research, laser-excited fluorescence was examined for sensitive detection of aqueous dityrosine. Samples were excited with a 6.3-mW, 325-nm helium-cadmium laser focused into a small volume-fluorescence cell with a 10-cm lens. The resulting fluorescence emission was collected perpendicular to the excitation and detected with two different schemes. An optical bandpass filter was used with a photomultiplier tube for sensitive quantitative measurement, while a photodiode array detector was used in conjunction with a spectrograph for qualitative characterization of fluorescence emission spectra. Dityrosine detection on the order of 2 × 10−11 M was obtained with the use of the photomultiplier tube with bandpass optical filter. The dityrosine fluorescence yield is found to vary with the solution pH, the relative concentrations of ferric and ferrous iron, and the amount of dissolved oxygen. A maximum fluorescence yield is observed for iron-free, oxygen-free alkaline solutions. Fluorescence quenching by oxygen is a cumulative photolysis effect that diminished fluorescence yield with increased irradiation time. Flowing the solutions minimized photolysis effects in oxygenated solutions. Quenching by ferrous and ferric iron is found to be due primarily to complex formation. The ferrous iron complex appears to have a fluorescence efficiency of ∼20% of the free dityrosine. The ferric iron dityrosine complex appears to have two ferric ions per molecule at low iron concentration. Other complexes may form at different concentrations. Solvent effects on dityrosine absorption and fluorescence spectra were also investigated. A red shift in dityrosine fluorescence maximum was observed in 1 M trichloroacetic acid and in N, N-dimethylformamide. The fluorescence emission maximum was shifted to the blue in acetonitrile and glacial acetic acid. These shifts were attributed to typical solvochromic behavior.

scholarly journals Setup of a photomultiplier tube test bench for LHAASO-KM2A

2016 ◽  
Vol 40 (8) ◽  
pp. 086003 ◽  
Author(s):  
Xu Wang ◽  
Zhong-Quan Zhang ◽  
Ye Tian ◽  
Yan-Yan Du ◽  
Xiao Zhao ◽  
...  
Keyword(s):  
Test Bench ◽  
Photomultiplier Tube ◽  
Tube Test

Determination of Polymer Type and Content in Concrete Materials by FTIR and TGA

2015 ◽  
Vol 1129 ◽  
pp. 151-158
Author(s):  
Takako Tokura ◽  
Joyce Lim ◽  
Ai Ming Chua ◽  
Wey Liang Lee ◽  
James Wong
Keyword(s):  
Construction Materials ◽  
Attenuated Total Reflection ◽  
Polymer Materials ◽  
Accurate Information ◽  
Fine Aggregate ◽  
Group Information ◽  
Concrete Materials ◽  
Spectrum Matching ◽  
Polymer Type

Polymers are commonly used in concrete materials. The type and concentration of polymer are important information for stakeholders, because they have a critical impact on the properties of concrete materials. Therefore, reliable and accurate information is highly desirable. To this end, Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA) are used to analyze polymer contents in construction materials.FTIR spectroscopy is a suitable technique to identify the polymer type using IR spectrum matching. Additionally, functional group information can be easily obtained from each peak. Attenuated Total Reflection (ATR) method can be used to measure extracted polymers from construction materials to obtain IR spectra, and match against the library database to identify the polymer materials. TGA is one of the common thermal analysis methods. It measures the weight loss or gain of sample due to chemical reactions such as vaporization, decomposition and oxidation as a function of temperature. In this paper, we will discuss development of reliable analytical methods with which mixtures of polymer, fine aggregate and cement with different percentages of polymer content were prepared and evaluated.

Some results on the sensitivity of the RCA 4522 photomultiplier tube

1977 ◽  
Vol 146 (2) ◽  
pp. 389-390 ◽  
Author(s):  
K.J. Orford ◽  
R.J. Stubbs ◽  
W.D. Waddoup
Keyword(s):  
Photomultiplier Tube
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