Measurements of Raman scattering in the middle ultraviolet band from persistent chemical warfare agents

Kullander, Fredrik; Landström, Lars; Lundén, Hampus; Mohammed, Abdesalam; Olofsson, G.; Wästerby, Pär

doi:10.1117/12.2049815

Cited by 7 publications

(14 citation statements)

References 10 publications

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“…The corresponding radiant exposure (for 200 pulses of 10m J/cm 2 @ 270 nm) was around 2 J/cm 2 . This is less than what we have applied in previous measurements [4] and should be low enough to avoid photo degradation in the deep UV (wavelength scans down to 210 nm). Such effects have previously been observed for some of the tested substances, e.g.…”

Section: Experimental Methodsmentioning

confidence: 77%

“…of SPIE Vol. 9455 94550S-7 Figure 8 shows the differential Raman scattering cross section obtained by applying equation (4). The estimated cross sections appear to rise monotonically with decreasing laser excitation wavelength for all of the depicted lines.…”

Section: Resultsmentioning

confidence: 98%

“…The UV Raman scattering from the persistent agents tabun, mustard gas, VX and relevant simulants in the form of liquid surface contaminations has previously been measured using a laboratory experimental setup with a standoff distance of 1.4 meters [4]. Droplets having a volume of 1 µl were deposited on clean silicon wafers and irradiated with a tunable pulsed laser swept within the middle UV band.…”

Section: Introductionmentioning

confidence: 99%

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Experimental examination of ultraviolet Raman cross sections of chemical warfare agent simulants

et al. 2015

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Laser induced Raman scattering from the commonly used chemical warfare agent simulants dimethyl sulfoxide, tributyl phosphate, triethyl phosphonoacetate was measured at excitation wavelengths ranging from 210 to 410 nm using a pulsed laser based spectrometer system with a probing distance of 1.4 m and with a field of view on the target of less than 1mm. For the purpose of comparison with well explored reference liquids the Raman scattering from simulants was measured in the form of an extended liquid surface layer on top of a silicon wafer. This way of measuring enabled direct comparison to the Raman scattering strength from cyclohexane. The reference Raman spectra were used to validate the signal strength of the simulants and the calibration of the experimental set up. Measured UV absorbance functions were used to calculate Raman cross sections. Established Raman cross sections of the simulants make it possible to use them as reference samples when measuring on chemical warfare agents in droplet form.

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Section: Experimental Methodsmentioning

confidence: 77%

Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Experimental examination of ultraviolet Raman cross sections of chemical warfare agent simulants

et al. 2015

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“…Previous studies have shown that the Raman scattering strength reaches a peak in the middle ultraviolet region (MUV=200nm to 300nm) and may become substantially higher than the NIR Raman strength for many of the low volatile CWA of interest to this study [3]. The Raman cross section increases with laser excitation frequency but the apparent signal strength is countered by absorption that typically results in a maximum signal strength in the MUV.…”

Section: Introductionmentioning

confidence: 79%

Ultraviolet Raman scattering from persistent chemical warfare agents

2016

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Laser induced Raman scattering at excitation wavelengths in the middle ultraviolet was examined using a pulsed tunable laser based spectrometer system. Droplets of chemical warfare agents, with a volume of 2 µl, were placed on a silicon surface and irradiated with sequences of laser pulses. The Raman scattering from V-series nerve agents, Tabun (GA) and Mustard gas (HD) was studied with the aim of finding the optimum parameters and the requirements for a detection system. A particular emphasis was put on V-agents that have been previously shown to yield relatively weak Raman scattering in this excitation band.

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“…The availability of high peak-power laser systems capable of delivering intense deep-UV pulses has brought renewed interest into using Raman spectroscopy as an analytical technique for stand-off detection. [1][2][3][4][5] Given that Raman scattering cross-sections are one billion times smaller than typical fluorescence cross-sections, overcoming the nine orders of magnitude decrease in sensitivity is a daunting challenge that remains to be addressed. [7][8][9][10] One strategy to increase Raman scattering cross-sections is to use UV photons as the scattering source.…”

Section: Introductionmentioning

confidence: 99%

Deep-UV standoff Raman spectroscopy

Arnold

Bowman

Scheurer

2019

Next-Generation Spectroscopic Technologies XII

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The availability of high peak-power laser systems capable of delivering intense deep-UV pulses has brought renewed interest in using Raman spectroscopy as both a selective and sensitive analytical technique for stand-off detection. Our approach uses a high power pulsed-laser as the excitation source, specifically the fourth and fifth harmonics of a Nd:YAG laser. One of the hurdles to be overcome to allow deep-UV Raman spectroscopy to become accessible is a direct method of calibrating both the observation frequency and detector response of the spectrograph being used. This report outlines our efforts to understand the photochemical and photophysical consequences of high-peak power excitation of cyclohexane for potential use as a secondary Raman standard in the deep-UV. Evaluation of the photochemical stability, both from multi-photon absorption and in the presence or absence of dissolved oxygen as well as the possibility of (near) resonance enhancement of the C-H stretching region will be described.

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Measurements of Raman scattering in the middle ultraviolet band from persistent chemical warfare agents

Cited by 7 publications

References 10 publications

Experimental examination of ultraviolet Raman cross sections of chemical warfare agent simulants

Experimental examination of ultraviolet Raman cross sections of chemical warfare agent simulants

Ultraviolet Raman scattering from persistent chemical warfare agents

Deep-UV standoff Raman spectroscopy

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