Thermal-imaging camera tubes with pyroelectric targets

Pyroelectric targets for thermal television can have broad spectral bandwidth, fast response to chopped signals and can operate uncooled. Analysis shows that targets of triglycine sulphate (TGS) are capable of good spatial resolution and high responsivity in practical thicknesses. The noise sources and constraints for electron beam readout in both cathode-potential and anode-potential stabilized modes are discussed, and favourable values of target resistivity and beam conductance have been measured. Predicted performance has been confirmed in demountable and sealed-off tubes working at standard television frame rates. The techniques described have also been used to make novel observations of the dynamics of domain growth in TGS.