1. Brucites exhibit the pyroelectric effect

2. Surface acoustic wave component on a monocrystal substrate which is also pyroelectric

3. The absorber layer (2) is advantageously also electroconductive in order to be able to divert pyroelectric charges.

4. A signal processor which only amplifies AC signals included in input signals (Vin) inputted from a pyroelectric infrared sensor (1) at a prescribed amplification factor.

5. The present invention relates to an apparatus for generating neutrons by accelerating ionized gas using the potential difference between surface charges induced on cross-sections of both ends of a pyroelectric crystal by applying radiant heat to the crystal, and a neutron target.