title: CO2 laser photoacoustic measurements of ethanol absorption coefficients within infrared region of 9.2-10.8 μm.
abstract: Absorption coefficients of the ethanol vapors at atmospheric pressure and room temperature were measured by photoacoustic technique using a cw, line-tunable, frequency-stabilized CO2 laser as radiation source. The spectrum of the employed CO2 laser includes 54 lines with wavelengths in the infrared region of 9.2-10.8μm and power levels up to 4.7W. Measurements revealed a predominant absorption for ethanol within 9.4μm band of the CO2 laser spectrum, where the highest values of the absorption coefficients were recorded: 3.68cm(-1)atm(-1) at 9R(20) line and 3.65cm(-1)atm(-1) at 9R(22) line. The estimated detection range covers six orders of magnitude, from a minimum of 30ppbV to a maximum of 4% concentration of ethanol in nitrogen, which proves the suitability of the photoacoustic technique for accurate measurements of the ethanol concentration in various applications.
authors.affiliation: Department of Lasers, National Institute for Laser, Plasma, and Radiation Physics, 409 Atomistilor St., PO Box MG-36, 077125 Magurele, Bucharest, Romania; Physics Department, Faculty of Applied Sciences, University "Politehnica" of Bucharest, 313 Splaiul Independentei, Bucharest 060042, Romania. Electronic address: ioana.ivascu@inflpr.ro.
authors.forename: I R
authors.initials: IR
authors.lastname: Ivascu
authors.affiliation: Department of Lasers, National Institute for Laser, Plasma, and Radiation Physics, 409 Atomistilor St., PO Box MG-36, 077125 Magurele, Bucharest, Romania.
authors.forename: C E
authors.initials: CE
authors.lastname: Matei
authors.affiliation: Department of Lasers, National Institute for Laser, Plasma, and Radiation Physics, 409 Atomistilor St., PO Box MG-36, 077125 Magurele, Bucharest, Romania.
authors.forename: M
authors.initials: M
authors.lastname: Patachia
authors.affiliation: Department of Lasers, National Institute for Laser, Plasma, and Radiation Physics, 409 Atomistilor St., PO Box MG-36, 077125 Magurele, Bucharest, Romania.
authors.forename: A M
authors.initials: AM
authors.lastname: Bratu
authors.affiliation: Department of Lasers, National Institute for Laser, Plasma, and Radiation Physics, 409 Atomistilor St., PO Box MG-36, 077125 Magurele, Bucharest, Romania; Physics Department, Faculty of Applied Sciences, University "Politehnica" of Bucharest, 313 Splaiul Independentei, Bucharest 060042, Romania.
authors.forename: D C
authors.initials: DC
authors.lastname: Dumitras
keywords: Absorption spectrum; CO(2) laser; Ethanol; Photoacoustic technique