Residual nuclide production is studied experimentally by bombarding a Cu target with a 250 MeV proton beam. The data are measured by the off-line gamma-spectroscopy method. Six nuclides are identified and their cross sections are determined. The corresponding calculated results by the MCNPX and GEANT4 codes are compared with the experimental data to check the validity of the codes. A comparison shows that the MCNPX simulation has a better agreement with the experiment. The energy dependence of residual nuclide production is studied with the aid of MCNPX simulation, and it is found that the mass yields for the nuclides in the light mass region increase significantly with the proton energy.

T he liquid metal loop is an essential experimental facility for carrying out key technological and experimental verifications of liquid metal spallation target . Gallium has lower melting point and very high boiling point ,and is non-toxicity ,so it could be used as a simulation medium in experiments of liquid metal loop .The design idea ,struc-tural component ,basic function and operation process of a small-scale liquid metal galli-um loop were described .The liquid gallium is driven by a variable frequency centrifugal pump to generate forced convection , simultaneously , the flow , pressure , differential pressure in the loop ,and the position and shape of the free surface in the windowless target were measured .Finally ,the changes of the pressure ,differential pressure ,and free surface position with the flow were analyzed .The results show that the free surface position depends on pressure and flow velocity .

Because of the existence of supercooling in a droplet formation chamber,the hydrogen micro-spheres are still in liquid phase even though their temperature is lower than the triple-point temperature.This may cause the droplets to shatter in the vacuum injection capillary.Based on the knowledge about supercooling of liquid hydrogen,we have done a thermodynamic simulation of the droplets in the droplet formation chamber,and theoretically suggested the optimal working conditions under which the droplets will most properly nucleate to solid pellets.The suggested working conditions are that the helium-gas pressure and the hydrogen vapor pressure in the droplet formation chamber are kept as low as possible,and thedroplet formation chamber should be no-less than 6 cm in the length.

The testing of a doubled-sided multi-strip silicon detector manufactured by Institute of Modern Physics of CAS and Peking University were introduced.The electrical characteristics and energy resolution,two-dimensional spectrum,crosstalk were presented.The reverse leak current of each strip is smaller than 10 nA under bias voltage of 25 V.The energy resolution of strips on the front side is about 1.5%,but a little worse for the backside strips,about 3%.The level of crosstalk is about 6% for the front side,1% for the backside.Same tests were carried out on the commercial Micron BB1 detector and a comparison was presented.