The cryostat system consists of a vacuum system

a temperature control set and a cryostat device. The performance of the system is as follows; Range of temperature adjustable

-187—500℃; Time of temperature equilibrium

1-5 min

longer for very low temperature; Vacuum

133.3-13.33 Pa; Resolution (FMHM) increase of the positron lifetime system

~10ps; Energy resolution of the

γ

-ray spectrometer

no change. No leakage of the radiation source was found. The cover

cooled by water

keeps nearly room temperature. The system has been used successfully for experiments of positron annihilation and annealing of ion-implanted semiconductor samples.