TY - JOUR
T1 - Multichannel emission spectrometer for high dynamic range optical pyrometry of shock-driven materials
AU - Bassett, Will P.
AU - Dlott, Dana D.
N1 - The research described in this study is based on work supported by the US Army Research Office under Award No. W911NF-13-1-0217, the US Air Force Office of Scientific Research under Awards Nos. FA9550-14-1-0142 and FA9550-16-1-0042, and the Defense Threat Reduction Agency under Award No. HDTRA1-12-1-0011. Will P. Bassett acknowledges support from the Stewardship Sciences Academic Alliance Program from the Carnegie-DOE Alliance Center, under Grant No. DE-NA20002006.
PY - 2016/10/1
Y1 - 2016/10/1
N2 - An emission spectrometer (450-850 nm) using a high-throughput, high numerical aperture (N.A. = 0.3) prism spectrograph with stepped fiberoptic coupling, 32 fast photomultipliers and thirty-two 1.25 GHz digitizers is described. The spectrometer can capture single-shot events with a high dynamic range in amplitude and time (nanoseconds to milliseconds or longer). Methods to calibrate the spectrometer and verify its performance and accuracy are described. When a reference thermal source is used for calibration, the spectrometer can function as a fast optical pyrometer. Applications of the spectrometer are illustrated by using it to capture single-shot emission transients from energetic materials or reactive materials initiated by km's-1 impacts with laser-driven flyer plates. A log (time) data analysis method is used to visualize multiple kinetic processes resulting from impact initiation of HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) or a Zr/CuO nanolaminate thermite. Using a gray body algorithm to interpret the spectral radiance from shocked HMX, a time history of temperature and emissivity was obtained, which could be used to investigate HMX hot spot dynamics. Finally, two examples are presented showing how the spectrometer can avoid temperature determination errors in systems where thermal emission is accompanied by atomic or molecular emission lines.
AB - An emission spectrometer (450-850 nm) using a high-throughput, high numerical aperture (N.A. = 0.3) prism spectrograph with stepped fiberoptic coupling, 32 fast photomultipliers and thirty-two 1.25 GHz digitizers is described. The spectrometer can capture single-shot events with a high dynamic range in amplitude and time (nanoseconds to milliseconds or longer). Methods to calibrate the spectrometer and verify its performance and accuracy are described. When a reference thermal source is used for calibration, the spectrometer can function as a fast optical pyrometer. Applications of the spectrometer are illustrated by using it to capture single-shot emission transients from energetic materials or reactive materials initiated by km's-1 impacts with laser-driven flyer plates. A log (time) data analysis method is used to visualize multiple kinetic processes resulting from impact initiation of HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) or a Zr/CuO nanolaminate thermite. Using a gray body algorithm to interpret the spectral radiance from shocked HMX, a time history of temperature and emissivity was obtained, which could be used to investigate HMX hot spot dynamics. Finally, two examples are presented showing how the spectrometer can avoid temperature determination errors in systems where thermal emission is accompanied by atomic or molecular emission lines.
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U2 - 10.1063/1.4964386
DO - 10.1063/1.4964386
M3 - Article
C2 - 27802768
AN - SCOPUS:84991577807
SN - 0034-6748
VL - 87
JO - Review of Scientific Instruments
JF - Review of Scientific Instruments
IS - 10
M1 - 103107
ER -