Irradiation effects in Ni-17Mo-7Cr alloy, which is an newly developed structural material for molten salt reactor (MSR), have been systematically investigated by using 3MeV Au ions at different fluences, corresponding to dpa number (displacement per
atom) of 1~ 30. GIXRD measurement indicates that the microstrain of the irradiated samples increased from 0.14% to 0.22% as dpa increased from 1 to 30. In the meanwhile, nanoindentation results reveal the Ni-17Mo-7Cr alloy underwent radiation-induced hardening first and then softening at dpa of 30. The swelling rate of Ni-17Mo-7Cr alloy was found around 1.3% at 30 dpa, which means only 0.04% per dpa. Besides, Raman spectra shows that carbon segregation appeared after Au ions irradiation. Our results are very helpful for understanding irradiation damages in Nickel-base alloys, especially for those in purpose of being used in future MSR nuclear energy system.
For the purpose to produce high intensity, multiply charged metal ion beams, the DUHOCAMIS (dual hollow cathode ion source for metal ions) was derived from the hot cathode Penning ion source combined with the hollow cathode sputtering experiments in
2007. It was interesting to investigate the behavior of this discharge geometry in a stronger magnetic bottle-shaped field. So a new test bench for DUHOCAMIS with a high magnetic bottle-shaped field up to 0.6 T has been set up at Peking University, on which have been made primary experiments in connection with discharge characteristics of the source. The experiments with magnetic fields from 0.13 T to 0.52 T have shown that the magnetic flux densities are very sensitive to the discharge behavior: discharge curves and ion spectra. It has been found that the slope of discharge curves in a very wide range can be controlled by changing the magnetic field as well as regulated by adjusting cathode heating power. On the other hand, by comparison of discharge curves between dual hollow cathode discharge (DHCD) mode and PIG discharge mode, it was found a much stronger magnetic effect occurred on DHCD mode. In this paper, the new test bench with ion source structure is described in detail; and main experimental results are presented and discussed, including the effects of cathode heating power and magnetic flux density on discharge characteristics, also the ion spectra. The effects of the magnetic field on the source operating are emphasized, and a unique behavior of the DUHOCAMIS operating in the high magnetic field is expected and discussed especially.
Using the non-relativisitc reduction of Coulomb gauge QCD we compute spectrum of the low mass hybrid mesons containing a heavy quark-antiquark pair. The gluon degrees of freedom are treated in the mean field approximation calibrated to the gluelump s
pectrum. We discuss the role of the non-abelian nature of the QCD Coulomb interaction in the ordering of the spin-parity levels.
We compute the energy spectrum of gluelumps defined as gluonic excitations bound to a localized, static octet source. We are able to reproduce the nontrivial ordering of the spin-parity levels and show how this is related to the non-abelian part of the Coulomb interaction between color charges.
