A laser-photolysis fragment-fluorescence (LPFF) method for the detection of gaseous nitric acid in ambient air

1990 ◽  
Vol 10 (4) ◽  
pp. 451-469 ◽  
Author(s):  
Th. Papenbrock ◽  
F. Stuhl
Keyword(s):  
Nitric Acid ◽  
Ambient Air ◽  
Laser Photolysis

scholarly journals Radon daughter removal from PTFE surfaces and its application in liquid xenon detectors

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
S. Bruenner ◽  
D. Cichon ◽  
G. Eurin ◽  
P. Herrero Gómez ◽  
F. Jörg ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Lead Isotopes ◽  
Ambient Air ◽  
Low Energy ◽  
Small Scale ◽  
Liquid Xenon ◽  
Radon Daughters ◽  
Radon Daughter ◽  
Cleaning Procedures ◽  
The Impact

AbstractLong-lived radon daughters are a critical background source in experiments searching for low-energy rare events. Originating from radon in ambient air, radioactive polonium, bismuth and lead isotopes plate-out on materials that are later employed in the experiment. In this paper, we examine cleaning procedures for their capability to remove radon daughters from PTFE surfaces, a material often used in liquid xenon TPCs. We find a large difference between the removal efficiency obtained for the decay chains of $$^{222}$$ 222 Rn and $$^{220}$$ 220 Rn. This indicates that the plate-out mechanism has an effect on the cleaning success. While the long-lived $$^{222}$$ 222 Rn daughters can be reduced by a factor of  2, the removal of $$^{220}$$ 220 Rn daughters is up to 10 times more efficient depending on the treatment. Furthermore, the impact of a nitric acid based PTFE cleaning on the liquid xenon purity is investigated in a small-scale liquid xenon TPC.

A comparison of filter, denuder, and real-time chemiluminescence techniques for nitric acid determination in ambient air

1989 ◽  
Vol 23 (10) ◽  
pp. 2213-2222 ◽  
Author(s):  
Roger L. Tanner ◽  
Thomas J. Kelly ◽  
Derek A. Dezaro ◽  
Joseph Forrest
Keyword(s):  
Nitric Acid ◽  
Real Time ◽  
Ambient Air ◽  
Acid Determination

scholarly journals Investigation of potential interferences in the detection of atmospheric RO<sub><i>x</i></sub> radicals by laser-induced fluorescence under dark conditions

2015 ◽  
Vol 8 (11) ◽  
pp. 12475-12523
Author(s):  
H. Fuchs ◽  
Z. Tan ◽  
A. Hofzumahaus ◽  
S. Broch ◽  
H.-P. Dorn ◽  
...  
Keyword(s):  
Direct Detection ◽  
Experimental Studies ◽  
Chemical Conversion ◽  
Ambient Air ◽  
Laser Induced Fluorescence ◽  
Laser Photolysis ◽  
Interference Signal ◽  
Nitrate Radical ◽  
Peroxy Radicals ◽  
Atmospheric Conditions

Abstract. Direct detection of highly reactive, atmospheric hydroxyl radicals (OH) is widely accomplished by laser-induced fluorescence (LIF) instruments. The technique is also suitable for the indirect measurement of HO2 and RO2 peroxy radicals by chemical conversion to OH. It requires sampling of ambient air into a low pressure cell, where OH fluorescence is detected after excitation by 308 nm laser radiation. Although the residence time of air inside the fluorescence cell is typically only on the order of milliseconds, there is potential that additional OH is internally produced, which would artificially increase the measured OH concentration. Here, we present experimental studies investigating potential interferences in the detection of OH and peroxy radicals for the LIF instruments of Forschungszentrum Jülich for nighttime conditions. For laboratory experiments, the inlet of the instrument was overflown by excess synthetic air containing one or more reactants. In order to distinguish between OH produced by reactions upstream of the inlet and artificial signals produced inside the instrument, a chemical titration for OH was applied. Additional experiments were performed in the simulation chamber SAPHIR where simultaneous measurements by an open-path differential optical absorption spectrometer (DOAS) served as reference for OH to quantify potential artifacts in the LIF instrument. Experiments included the investigation of potential interferences related to the nitrate radical (NO3, N2O5), related to the ozonolysis of alkenes (ethene, propene, 1-butene, 2,3-dimethyl-2-butene, α-pinene, limonene, isoprene), and the laser photolysis of acetone. Experiments studying the laser photolysis of acetone yield OH signals in the fluorescence cell, which are equivalent to 0.05 × 106 cm−3 OH for a mixing ratio of 5 ppbv acetone. Under most atmospheric conditions, this interference is negligible. No significant interferences were found for atmospheric concentrations of reactants during ozonolysis experiments. Only for α-pinene, limonene, and isoprene at reactant concentrations which are orders of magnitude higher than in the atmosphere artificial OH could be detected. The value of the interference depends on the turnover rate of the ozonolysis reaction. For example, an apparent OH concentration of approximately 1 × 106 cm−3 is observed, if 5.8 ppbv limonene reacts with 600 ppbv ozone. Experiments with the nitrate radical NO3 reveal a small interference signal in the OH, HO2 and RO2 detection. Dependencies on experimental parameters point to artificial OH formation by surface reactions at the chamber walls or in molecular clusters in the gas expansion. The signal scales with the presence of NO3 giving equivalent radical concentrations of 1.1 × 105 cm−3 OH, 1 × 107 cm−3 HO2, and 1.7 × 107 cm−3 RO2 per 10 pptv NO3.

scholarly journals Investigation of potential interferences in the detection of atmospheric RO<sub><i>x</i></sub> radicals by laser-induced fluorescence under dark conditions

2016 ◽  
Vol 9 (4) ◽  
pp. 1431-1447 ◽  
Author(s):  
Hendrik Fuchs ◽  
Zhaofeng Tan ◽  
Andreas Hofzumahaus ◽  
Sebastian Broch ◽  
Hans-Peter Dorn ◽  
...  
Keyword(s):  
Direct Detection ◽  
Experimental Studies ◽  
Chemical Conversion ◽  
Ambient Air ◽  
Laser Induced Fluorescence ◽  
Laser Photolysis ◽  
Interference Signal ◽  
Nitrate Radical ◽  
Peroxy Radicals ◽  
Atmospheric Conditions

Abstract. Direct detection of highly reactive, atmospheric hydroxyl radicals (OH) is widely accomplished by laser-induced fluorescence (LIF) instruments. The technique is also suitable for the indirect measurement of HO2 and RO2 peroxy radicals by chemical conversion to OH. It requires sampling of ambient air into a low-pressure cell, where OH fluorescence is detected after excitation by 308 nm laser radiation. Although the residence time of air inside the fluorescence cell is typically only on the order of milliseconds, there is potential that additional OH is internally produced, which would artificially increase the measured OH concentration. Here, we present experimental studies investigating potential interferences in the detection of OH and peroxy radicals for the LIF instruments of Forschungszentrum Jülich for nighttime conditions. For laboratory experiments, the inlet of the instrument was over flowed by excess synthetic air containing one or more reactants. In order to distinguish between OH produced by reactions upstream of the inlet and artificial signals produced inside the instrument, a chemical titration for OH was applied. Additional experiments were performed in the simulation chamber SAPHIR where simultaneous measurements by an open-path differential optical absorption spectrometer (DOAS) served as reference for OH to quantify potential artifacts in the LIF instrument. Experiments included the investigation of potential interferences related to the nitrate radical (NO3, N2O5), related to the ozonolysis of alkenes (ethene, propene, 1-butene, 2,3-dimethyl-2-butene, α-pinene, limonene, isoprene), and the laser photolysis of acetone. Experiments studying the laser photolysis of acetone yield OH signals in the fluorescence cell, which are equivalent to 0.05 × 106 cm−3 OH for a mixing ratio of 5 ppbv acetone. Under most atmospheric conditions, this interference is negligible. No significant interferences were found for atmospheric concentrations of reactants during ozonolysis experiments. Only for propene, α-pinene, limonene, and isoprene at reactant concentrations, which are orders of magnitude higher than in the atmosphere, could artificial OH be detected. The value of the interference depends on the turnover rate of the ozonolysis reaction. For example, an apparent OH concentration of approximately 1 × 106 cm−3 is observed when 5.8 ppbv limonene reacts with 600 ppbv ozone. Experiments with the nitrate radical NO3 reveal a small interference signal in the OH, HO2, and RO2 detection. Dependencies on experimental parameters point to artificial OH formation by surface reactions at the chamber walls or in molecular clusters in the gas expansion. The signal scales with the presence of NO3 giving equivalent radical concentrations of 1.1 × 105 cm−3 OH, 1 × 107 cm−3 HO2, and 1.7 × 107 cm−3 RO2 per 10 pptv NO3.

Tungstic acid technique for monitoring nitric acid and ammonia in ambient air

1982 ◽  
Vol 54 (3) ◽  
pp. 365-369 ◽  
Author(s):  
W. A. McClenny ◽  
P. C. Gailey ◽  
R. S. Braman ◽  
T. J. Shelley
Keyword(s):  
Nitric Acid ◽  
Ambient Air ◽  
Tungstic Acid

Excitation mechanism for hydroxyl(A) in the argon fluoride excimer laser photolysis of nitric acid

1986 ◽  
Vol 90 (7) ◽  
pp. 1294-1299 ◽  
Author(s):  
R. D. Kenner ◽  
F. Rohrer ◽  
T. Papenbrock ◽  
F. Stuhl
Keyword(s):  
Nitric Acid ◽  
Excimer Laser ◽  
Laser Photolysis ◽  
Excitation Mechanism ◽  
Argon Fluoride

Determination of nitric acid in ambient air using diffusion denuder tubes

Talanta ◽  
1992 ◽  
Vol 39 (11) ◽  
pp. 1463-1469 ◽  
Author(s):  
G.B. Marshall ◽  
N.A. Dimmock
Keyword(s):  
Nitric Acid ◽  
Ambient Air
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