The V- centre (a hole trapped on a sulphide ion near an isolated cation vac
ancy) is studied by EPR in CaS polycrystals irradiated with reactor neutron
s. Its properties are compared with those of the V- centre in plastically d
eformed samples. The g(perpendicular to) value of V- differs only slightly
(2.1244 in irradiated samples versus 2.1240 in deformed ones), and the corr
esponding EPR line is wider in plastically deformed CaS. Holes are released
in both cases in a wide temperature range of 120-285 K, Ionic processes ar
e studied up to 1000 K. Processes of lattice damage and restoration are sim
ilar both in neutron-irradiated and plastically deformed CaS. (C) 1999 Else
vier Science Ltd. All rights reserved.