A neutron time-of-flight (nTOF) system has been implemented at the largest laser facility in China. The nTOF system is used to measure neutron spectra in inertial confinement fusion experiments. The nTOF system consists of 11 fast plastic scintillation detectors.
View Article and Find Full Text PDFThe first octahedral spherical hohlraum energetics experiment is accomplished at the SGIII laser facility. For the first time, the 32 laser beams are injected into the octahedral spherical hohlraum through six laser entrance holes. Two techniques are used to diagnose the radiation field of the octahedral spherical hohlraum in order to obtain comprehensive experimental data.
View Article and Find Full Text PDFThe accuracy of the determination of the burn-averaged ion temperature of inertial confinement fusion implosions depends on the unfold process, including deconvolution and convolution methods, and the function, i.e., the detector response, used to fit the signals measured by neutron time-of-flight (nToF) detectors.
View Article and Find Full Text PDFOctahedral spherical hohlraums with a single laser ring at an injection angle of 55^{∘} are attractive concepts for laser indirect drive due to the potential for achieving the x-ray drive symmetry required for high convergence implosions. Laser-plasma instabilities, however, are a concern given the long laser propagation path in such hohlraums. Significant stimulated Raman scattering has been observed in cylindrical hohlraums with similar laser propagation paths during the ignition campaign on the National Ignition Facility (NIF).
View Article and Find Full Text PDFThe first spherical hohlraum energetics experiment is accomplished on the SGIII-prototype laser facility. In the experiment, the radiation temperature is measured by using an array of flat-response x-ray detectors (FXRDs) through a laser entrance hole at four different angles. The radiation temperature and M-band fraction inside the hohlraum are determined by the shock wave technique.
View Article and Find Full Text PDFA neutron bang time (NBT) diagnostic system has been implemented on Shenguang-III prototype. The bang time diagnostic system is based on a sensitive fusion neutron detector, which consists of a plastic scintillator and a micro-channel plate photomultiplier tube (PMT). An optical fiber bundle is used to couple the scintillator and the PMT.
View Article and Find Full Text PDFA type of low-pass filter devices for soft x rays is investigated by using a microchannel plate (MCP) of small channels with square cross section. The measured transmission spectra on the Beijing Synchrotron Radiation Facility showed that the MCP has excellent bandpass effects below 1.5 keV by grazing incidence and internal multireflections.
View Article and Find Full Text PDFThe proposal of simultaneously determining the hohlraum peak radiation temperature T(R) and M-band fraction f(M) by shock velocity measurement technique [Y. S. Li et al.
View Article and Find Full Text PDFIn the test run of Shenguang III laser prototype facility, under the low density condition, the yield ratio method was used to measure the fuel areal density. Considering the uncertainty of the neutron yield, detectors with different efficiencies were used. The clear secondary-neutron signals in inertial confinement fusion experiments were obtained for the first time in China, and the values of the areal density were deduced.
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