Real-time wide-range neutron flux monitor for thorium-based molten salt reactor

A novel full-digital real-time neutron flux monitor(NFM) has been developed for thorium-based molten salt reactor(TMSR).The system is based on the highspeed,parallel,and pipeline processing of the field programmable gate array as well as the high-stability controller area network platform.A measurement range of 10~8 counts per second is achieved with a single fission chamber by utilizing the normalization of the count and Campbell algorithms.With the advantages of using the measurement range,system integrity,and real-time performance,digital NFM has been tested in the Xi'an pulsed reactor fission experiments and was found to exhibit superior experimental performance.

Testing the first law of black hole mechanics with gravitational waves

The successful observation of gravitational waves has provided humanity with an additional method to explore the universe,particularly black holes.In this study,we utilize data from LIGO and Virgo gravitational wave observations to test the first law of black hole mechanics,employing two different approaches.We consider the secondary compact object as a perturbation to the primary black hole before the merger,and the remnant black hole as a stationary black hole after the merger.In the pre-merger and post-merger analysis,our results demonstrate consistency with the first law,with an error level of approximate 25%at a68%credibility level for GW190403051519.In the full inspiral-merger-ringdown analysis,our results show consistency with the first law of black hole mechanics,with an error level of about 6%at a 68%credibility level and 10%at a 95%credibility level for GW191219163120.Additionally,we observe that the higher the mass ratio of the gravitational wave source,the more consistent our results are with the first law of black hole mechanics.Overall,our study sheds light on the nature of compact binary coalescence and their implications for black hole mechanics.

Dynamics of High-Order Spin-Orbit Couplings about Linear Momenta in Compact Binary Systems

This paper relates to the post-Newtonian Hamiltonian dynamics of spinning compact binaries, consisting of the Newtonian Kepler problem and the leading, next-to-leading and next-to-next-to-leading order spin-orbit couplings as linear functions of spins and momenta. When this Hamiltonian form is transformed to a Lagrangian form, besides the terms corresponding to the same order terms in the Hamiltonian, several additional terms, third post-Newtonian(3 PN),4 PN, 5 PN, 6 PN and 7 PN order spin-spin coupling terms, yield in the Lagrangian. That means that the Hamiltonian is nonequivalent to the Lagrangian at the same PN order but is exactly equivalent to the full Lagrangian without any truncations. The full Lagrangian without the spin-spin couplings truncated is integrable and regular. Whereas it is non-integrable and becomes possibly chaotic when any one of the spin-spin terms is dropped. These results are also supported numerically.