The

147

Pm-excited ZnS:Cu

Cl luminescence powders are the important radioactive luminescence materials. They are used widely in the feeble illumination. Now they are investigated and produced only at Tsinghua University in China. The preparation and the luminescence properties of

147

Pm-excited ZnS:Cu

Cl luminescent powders are investigated in this paper. The ZnSpowders with high pureness were used as the matrices. It is a direct bandgap semiconductor. Firstly the ZnSpowders were mixed with CuCl

2

and the flux uniformly. Then the homogeneous mixtures were calcinated in the furnace for 1.5 hours at 1150℃ to make the ZnS:Cu

Cl powders. At the same time it changed to the hexagonal crystals. Finally the ZnS:Cu

Cl powders were coated with SiO

2

Na

2

SiO

3

and

147

Pm

2

O

3

. So the

147

Pm-excited ZnS:Cu

Cl luminescent powders were prepared. We detected the excitation spectrum and the emission spectrum of ZnS:Cu

Cl. The excitation spectrum of the ZnS:Cu

Cl tells that the maximal excitation intensity is at 341 nm. On the basis of that

we calculated the bangap energy of ZnS. It is about 3.64 eV. The emission spectrum of the ZnS:Cu

Cl tells that the maximal emission intensity is at 513 nm. The maximal brightness of the

147

Pm-excited ZnS:Cu

Cl is 312 mcd/m

2

. The analyses tell that the luminescence lifetime of this phosphor is longer than

5

years. The luminescence mechanism of the

147

Pm-excited ZnS:Cu

Cl is discussed in this paper too. The stable luminescence of the

147

Pm-excited ZnS:Cu

Cl is based on the quasi-equilibrium between the excitation and the recombination processes. The green luminescence of ZnS:Cu

Cl comes from the deep donors to the deep acceptors recombination emission. We calculated the energy level between the deep donors and the deep acceptors of ZnS:Cu

Cl according to the experiment results. It is about 2.42 eV.