The radiation temperature and M -band fraction inside hohlraum on the SGIII-prototype laser facility

The radiation temperature T{sub R} and M-band fraction f{sub 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{sub R} is about 202 eV, and f{sub 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{sub R} to 207 eV while has almost no influence on f{sub M}. Comparisons between the results from the two kinds of technologies show that T{sub R} from the shock wave technique is lower than that from SXS whether with CPP or not. However, f{sub 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.