  We investigate the Unruh effect on entanglement taking into account the spin
degree of freedom of the Dirac field. We analyze spin Bell states in this
setting, obtaining their entanglement dependance on the acceleration of one of
the partners. Then, we consider simple analogs to the occupation number
entangled state |00>+|11>, but with spin quantum numbers for |11> showing that,
despite their apparent similitude, while the spinless case is always qubit x
qubit, for the spin case acceleration produces a qubit x qu4it state. We also
introduce a procedure to consistently erase the spin information from our
setting preserving occupation numbers. We show how the maximally entangled
state for occupation number emerges from our setting, we also analyze its
entanglement dependance on acceleration, obtaining a greater entanglement
degradation than in the spinless case.
