We investigate particle detector responses in some topologically non-trivial
spacetimes. We extend a recently proposed regularization of the massless scalar
field Wightman function in 4-dimensional Minkowski space to arbitrary
dimension, to the massive scalar field, to quotients of Minkowski space under
discrete isometry groups and to the massless Dirac field. We investigate in
detail the transition rate of inertial and uniformly accelerated detectors on
the quotient spaces under groups generated by $(t,x,y,z)\mapsto(t,x,y,z+2a)$,
$(t,x,y,z)\mapsto(t,-x,y,z)$, $(t,x,y,z)\mapsto(t,-x,-y,z)$,
$(t,x,y,z)\mapsto(t,-x,-y,z+a)$ and some higher dimensional generalizations.
For motions in at constant $y$ and $z$ on the latter three spaces the response
is time dependent. We also discuss the response of static detectors on the RP^3
geon and inertial detectors on RP^3 de Sitter space via their associated global
embedding Minkowski spaces (GEMS). The response on RP^3 de Sitter space, found
both directly and in its GEMS, provides support for the validity of applying
the GEMS procedure to detector responses and to quotient spaces such as RP^3 de
Sitter space and the RP^3 geon where the embedding spaces are Minkowski spaces
with suitable identifications.Comment: 47 pages, 9 figure