TY - GEN
T1 - Standoff Detection of Solid Materials Using Laser Induced Fluorescence of Laser-Produced Plasmas
AU - Harilal, S. S.
AU - Brumfield, B. E.
AU - Phillips, M. C.
N1 - Funding Information:
________________________________ * Pacific Northwest National Laboratory is operated for the U.S. Department of Energy by the Battelle Memorial Institute under Contract No. DE-AC05-76RLO1830.
Publisher Copyright:
© 2018 IEEE.
PY - 2018/6/24
Y1 - 2018/6/24
N2 - Selective and sensitive detection technologies for rapid identification of substances at standoff distances are ultimately important for a large number of applications. For example, standoff, rapid detection is the most desired capability for an analytical tool for identifying dangerous substances in the field such as high-energy explosives and radioactive nuclear materials. Currently extensive efforts are going on to use emission spectroscopy of laser-produced plasma (LPP) or Laser-induced breakdown spectroscopy (LIBS) for standoff detection. However, the sensitivity of LIBS is poorer compared to sampling based detection techniques (eg. mass-spectroscopy). In addition to this, the spectral resolution available for all emission based methods are limited to instrumental broadening of the detection system. Laser-induced fluorescence (LIF) of LPPs can address these limitations.1 In LIF, a second laser is used to excite the lower-level or ground state population which exists during the entire lifespan of LPP even when the plasma is cooler in comparison with LIBS where hotter conditions are prerequisite for thermal excitation. By monitoring the plasma conditions at later times of its evolution there is a significant reduction in line broadening mechanisms in the plasma. The instrumental broadening with the LIF method is dictated by the linewidth of the probe laser, which for CW laser sources is very small ( a few femtometers).
AB - Selective and sensitive detection technologies for rapid identification of substances at standoff distances are ultimately important for a large number of applications. For example, standoff, rapid detection is the most desired capability for an analytical tool for identifying dangerous substances in the field such as high-energy explosives and radioactive nuclear materials. Currently extensive efforts are going on to use emission spectroscopy of laser-produced plasma (LPP) or Laser-induced breakdown spectroscopy (LIBS) for standoff detection. However, the sensitivity of LIBS is poorer compared to sampling based detection techniques (eg. mass-spectroscopy). In addition to this, the spectral resolution available for all emission based methods are limited to instrumental broadening of the detection system. Laser-induced fluorescence (LIF) of LPPs can address these limitations.1 In LIF, a second laser is used to excite the lower-level or ground state population which exists during the entire lifespan of LPP even when the plasma is cooler in comparison with LIBS where hotter conditions are prerequisite for thermal excitation. By monitoring the plasma conditions at later times of its evolution there is a significant reduction in line broadening mechanisms in the plasma. The instrumental broadening with the LIF method is dictated by the linewidth of the probe laser, which for CW laser sources is very small ( a few femtometers).
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U2 - 10.1109/ICOPS35962.2018.9575329
DO - 10.1109/ICOPS35962.2018.9575329
M3 - Conference contribution
AN - SCOPUS:85118956900
T3 - IEEE International Conference on Plasma Science
BT - ICOPS 2018 - 45th IEEE International Conference on Plasma Science
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 45th IEEE International Conference on Plasma Science, ICOPS 2018
Y2 - 24 June 2018 through 28 June 2018
ER -