Direct measurement of near-infrared (NIR) luminescence around 1270 nm is the golden standard of singlet
oxygen (1O2)
identification. In this study, the influence of pulse-height discrimination threshold on measurement accuracy
of the 1O2
luminescence that is generated from the photoirradiation of meso-tetra (N-methyl-4-pyridyl) morphine tetra-tosylate (TMPyP) in aqueous solution was
investigated by using our custom-developed detection system. Our results indicate
that the discrimination threshold has a significant influence on the absolute 1O2
luminescence counts, and the optimal threshold for our detection system is found to be about − 41.2 mV for signal discrimination. After optimization, the derived triplet-state and
1O2
lifetimes of TMPyP in aqueous solution are found to be
1.73 ± 0.03 and
3.70 ± 0.04 µs, respectively, and the accuracy of measurement was further independently demonstrated
using the laser flash photolysis technique.
The radiation temperature T R and M-band fraction f M inside the vacuum Au hohlraum have been experimentally determined by a shock wave technique and a broadband soft x-ray spectrometer (SXS) on the SGIII-prototype laser facility. From the results of the shock wave technique, T R is about 202 eV, and f M is about 9% for the hohlraums driven by a 1 ns flattop pulse of 6 kJ laser energy. The Continuous Phase Plate (CPP) for beam smoothing is applied in the experiment, which increases T R to 207 eV while has almost no influence on f M . Comparisons between the results from the two kinds of technologies show that T R from the shock wave technique is lower than that from SXS whether with CPP or not. However, f M from the shock wave technique is consistent with that from SXS without CPP, but obviously lower than the SXS's result with CPP. The preheat effect on exterior surface of witness plate is reduced by thicker thickness of witness plate designed for higher laser driven energy. V C 2014 AIP Publishing LLC. [http://dx.
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